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HyperalgesiaStress, MechanicalMechanical ProcessesBiomechanical PhenomenaMechanical PhenomenaRespiration, ArtificialMechanotransduction, CellularElasticityPhysical StimulationTensile StrengthElastic ModulusVentilators, MechanicalIsraelEritreaMotorcyclesUnited StatesFatsTooth PreparationWireless TechnologyPublicationsComputer Communication NetworksTelemetryCongresses as TopicSemiconductorsSodium HypochloritePatents as TopicColloidsSilicon DioxideCrystallizationIron Carbonyl CompoundsCytoskeletonCell NucleusModels, BiologicalSignal TransductionYogaChromatinStress, PhysiologicalStress, PsychologicalMortality, PrematureRestraint, PhysicalSyndecan-4MyofibroblastsSyndecan-1Cell DifferentiationSyndecan-2FibroblastsFinite Element AnalysisMicrotechnologyMicro-Electrical-Mechanical SystemsNanowiresEpithelioid CellsComputer Simulation
Hyperalgesia: An increased sensation of pain or discomfort produced by mimimally noxious stimuli due to damage to soft tissue containing NOCICEPTORS or injury to a peripheral nerve.Stress, Mechanical: A purely physical condition which exists within any material because of strain or deformation by external forces or by non-uniform thermal expansion; expressed quantitatively in units of force per unit area.Mechanical Processes: The behaviors of materials under force.Biomechanical Phenomena: The properties, processes, and behavior of biological systems under the action of mechanical forces.Mechanical Phenomena: The properties and processes of materials that affect their behavior under force.Respiration, Artificial: Any method of artificial breathing that employs mechanical or non-mechanical means to force the air into and out of the lungs. Artificial respiration or ventilation is used in individuals who have stopped breathing or have RESPIRATORY INSUFFICIENCY to increase their intake of oxygen (O2) and excretion of carbon dioxide (CO2).Mechanotransduction, Cellular: The process by which cells convert mechanical stimuli into a chemical response. It can occur in both cells specialized for sensing mechanical cues such as MECHANORECEPTORS, and in parenchymal cells whose primary function is not mechanosensory.Elasticity: Resistance and recovery from distortion of shape.Physical Stimulation: Act of eliciting a response from a person or organism through physical contact.Tensile Strength: The maximum stress a material subjected to a stretching load can withstand without tearing. (McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed, p2001)Elastic Modulus: Numerical expression indicating the measure of stiffness in a material. It is defined by the ratio of stress in a unit area of substance to the resulting deformation (strain). This allows the behavior of a material under load (such as bone) to be calculated.Ventilators, Mechanical: Mechanical devices used to produce or assist pulmonary ventilation.IsraelEritrea: A country of eastern Africa, west of the Red Sea, bordered west and northwest by SUDAN, and south by ETHIOPIA. Its capital is Asmara.Motorcycles: Two-wheeled, engine-driven vehicles.United StatesFats: The glyceryl esters of a fatty acid, or of a mixture of fatty acids. They are generally odorless, colorless, and tasteless if pure, but they may be flavored according to origin. Fats are insoluble in water, soluble in most organic solvents. They occur in animal and vegetable tissue and are generally obtained by boiling or by extraction under pressure. They are important in the diet (DIETARY FATS) as a source of energy. (Grant & Hackh's Chemical Dictionary, 5th ed)Tooth Preparation: Procedures carried out with regard to the teeth or tooth structures preparatory to specified dental therapeutic and surgical measures.Wireless Technology: Techniques using energy such as radio frequency, infrared light, laser light, visible light, or acoustic energy to transfer information without the use of wires, over both short and long distances.Publications: Copies of a work or document distributed to the public by sale, rental, lease, or lending. (From ALA Glossary of Library and Information Science, 1983, p181)Computer Communication Networks: A system containing any combination of computers, computer terminals, printers, audio or visual display devices, or telephones interconnected by telecommunications equipment or cables: used to transmit or receive information. (Random House Unabridged Dictionary, 2d ed)Telemetry: Transmission of the readings of instruments to a remote location by means of wires, radio waves, or other means. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Congresses as Topic: Conferences, conventions or formal meetings usually attended by delegates representing a special field of interest.Semiconductors: Materials that have a limited and usually variable electrical conductivity. They are particularly useful for the production of solid-state electronic devices.Sodium Hypochlorite: It is used as an oxidizing and bleaching agent and as a disinfectant. (From Grant & Hackh's Chemical Dictionary, 5th ed)Patents as Topic: Exclusive legal rights or privileges applied to inventions, plants, etc.Colloids: Two-phase systems in which one is uniformly dispersed in another as particles small enough so they cannot be filtered or will not settle out. The dispersing or continuous phase or medium envelops the particles of the discontinuous phase. All three states of matter can form colloids among each other.Silicon Dioxide: Transparent, tasteless crystals found in nature as agate, amethyst, chalcedony, cristobalite, flint, sand, QUARTZ, and tridymite. The compound is insoluble in water or acids except hydrofluoric acid.Crystallization: The formation of crystalline substances from solutions or melts. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Iron Carbonyl Compounds: Complex of iron atoms chelated with carbonyl ions.Cytoskeleton: The network of filaments, tubules, and interconnecting filamentous bridges which give shape, structure, and organization to the cytoplasm.Cell Nucleus: Within a eukaryotic cell, a membrane-limited body which contains chromosomes and one or more nucleoli (CELL NUCLEOLUS). The nuclear membrane consists of a double unit-type membrane which is perforated by a number of pores; the outermost membrane is continuous with the ENDOPLASMIC RETICULUM. A cell may contain more than one nucleus. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)Models, Biological: Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.Signal Transduction: The intracellular transfer of information (biological activation/inhibition) through a signal pathway. In each signal transduction system, an activation/inhibition signal from a biologically active molecule (hormone, neurotransmitter) is mediated via the coupling of a receptor/enzyme to a second messenger system or to an ion channel. Signal transduction plays an important role in activating cellular functions, cell differentiation, and cell proliferation. Examples of signal transduction systems are the GAMMA-AMINOBUTYRIC ACID-postsynaptic receptor-calcium ion channel system, the receptor-mediated T-cell activation pathway, and the receptor-mediated activation of phospholipases. Those coupled to membrane depolarization or intracellular release of calcium include the receptor-mediated activation of cytotoxic functions in granulocytes and the synaptic potentiation of protein kinase activation. Some signal transduction pathways may be part of larger signal transduction pathways; for example, protein kinase activation is part of the platelet activation signal pathway.Yoga: A major orthodox system of Hindu philosophy based on Sankhya (metaphysical dualism) but differing from it in being theistic and characterized by the teaching of raja-yoga as a practical method of liberating the self. It includes a system of exercises for attaining bodily or mental control and well-being with liberation of the self and union with the universal spirit. (From Webster, 3d ed)Chromatin: The material of CHROMOSOMES. It is a complex of DNA; HISTONES; and nonhistone proteins (CHROMOSOMAL PROTEINS, NON-HISTONE) found within the nucleus of a cell.Stress, Physiological: The unfavorable effect of environmental factors (stressors) on the physiological functions of an organism. Prolonged unresolved physiological stress can affect HOMEOSTASIS of the organism, and may lead to damaging or pathological conditions.Stress, Psychological: Stress wherein emotional factors predominate.Mortality, Premature: Deaths that occur before LIFE EXPECTANCY is reached within a given population.Restraint, Physical: Use of a device for the purpose of controlling movement of all or part of the body. Splinting and casting are FRACTURE FIXATION.Syndecan-4: A ubiquitously expressed syndecan that is found in all stages of embryonic development and in most adult tissues. Syndecan-4 is found localized to focal adhesion sites in fibronectin-adherent cells and may play a role the process of CELL MIGRATION and CELL PROLIFERATION.Myofibroblasts: Spindle-shaped cells with characteristic CONTRACTILE PROTEINS and structures that contribute to the WOUND HEALING process. They occur in GRANULATION TISSUE and also in pathological processes such as FIBROSIS.Syndecan-1: A syndecan that interacts with EXTRACELLULAR MATRIX PROTEINS and plays a role CELL PROLIFERATION and CELL MIGRATION.Cell Differentiation: Progressive restriction of the developmental potential and increasing specialization of function that leads to the formation of specialized cells, tissues, and organs.Syndecan-2: A syndecan that is predominantly expressed during EMBRYONIC DEVELOPMENT. It may play a role in mediating cellular interactions with the EXTRACELLULAR MATRIX and may modulate the signaling activity of certain INTERCELLULAR SIGNALING PEPTIDES AND PROTEINS.Fibroblasts: Connective tissue cells which secrete an extracellular matrix rich in collagen and other macromolecules.Finite Element Analysis: A computer based method of simulating or analyzing the behavior of structures or components.Microtechnology: Manufacturing technology for making microscopic devices in the micrometer range (typically 1-100 micrometers), such as integrated circuits or MEMS. The process usually involves replication and parallel fabrication of hundreds or millions of identical structures using various thin film deposition techniques and carried out in environmentally-controlled clean rooms.Micro-Electrical-Mechanical Systems: A class of devices combining electrical and mechanical components that have at least one of the dimensions in the micrometer range (between 1 micron and 1 millimeter). They include sensors, actuators, microducts, and micropumps.Nanowires: Nanometer-scale wires made of materials that conduct electricity. They can be coated with molecules such as antibodies that will bind to proteins and other substances.Epithelioid Cells: Characteristic cells of granulomatous hypersensitivity. They appear as large, flattened cells with increased endoplasmic reticulum. They are believed to be activated macrophages that have differentiated as a result of prolonged antigenic stimulation. Further differentiation or fusion of epithelioid cells is thought to produce multinucleated giant cells (GIANT CELLS).Computer Simulation: Computer-based representation of physical systems and phenomena such as chemical processes.

Insulin-like growth factor-1 induces Mdm2 and down-regulates p53, attenuating the myocyte renin-angiotensin system and stretch-mediated apoptosis. (1/9460)

Insulin-like growth factor (IGF)-1 inhibits apoptosis, but its mechanism is unknown. Myocyte stretching activates p53 and p53-dependent genes, leading to the formation of angiotensin II (Ang II) and apoptosis. Therefore, this in vitro system was used to determine whether IGF-1 interfered with p53 function and the local renin-angiotensin system (RAS), decreasing stretch-induced cell death. A single dose of 200 ng/ml IGF-1 at the time of stretching decreased myocyte apoptosis 43% and 61% at 6 and 20 hours. Ang II concentration was reduced 52% at 20 hours. Additionally, p53 DNA binding to angiotensinogen (Aogen), AT1 receptor, and Bax was markedly down-regulated by IGF-1 via the induction of Mdm2 and the formation of Mdm2-p53 complexes. Concurrently, the quantity of p53, Aogen, renin, AT1 receptor, and Bax was reduced in stretched myocytes exposed to IGF-1. Conversely, Bcl-2 and the Bcl-2-to-Bax protein ratio increased. The effects of IGF-1 on cell death, Ang II synthesis, and Bax protein were the consequence of Mdm2-induced down-regulation of p53 function. In conclusion, the anti-apoptotic impact of IGF-1 on stretched myocytes was mediated by its capacity to depress p53 transcriptional activity, which limited Ang II formation and attenuated the susceptibility of myocytes to trigger their endogenous cell death pathway.  (+info)

Fibrocartilage in tendons and ligaments--an adaptation to compressive load. (2/9460)

Where tendons and ligaments are subject to compression, they are frequently fibrocartilaginous. This occurs at 2 principal sites: where tendons (and sometimes ligaments) wrap around bony or fibrous pulleys, and in the region where they attach to bone, i.e. at their entheses. Wrap-around tendons are most characteristic of the limbs and are commonly wider at their point of bony contact so that the pressure is reduced. The most fibrocartilaginous tendons are heavily loaded and permanently bent around their pulleys. There is often pronounced interweaving of collagen fibres that prevents the tendons from splaying apart under compression. The fibrocartilage can be located within fascicles, or in endo- or epitenon (where it may protect blood vessels from compression or allow fascicles to slide). Fibrocartilage cells are commonly packed with intermediate filaments which could be involved in transducing mechanical load. The ECM often contains aggrecan which allows the tendon to imbibe water and withstand compression. Type II collagen may also be present, particularly in tendons that are heavily loaded. Fibrocartilage is a dynamic tissue that disappears when the tendons are rerouted surgically and can be maintained in vitro when discs of tendon are compressed. Finite element analyses provide a good correlation between its distribution and levels of compressive stress, but at some locations fibrocartilage is a sign of pathology. Enthesis fibrocartilage is most typical of tendons or ligaments that attach to the epiphyses of long bones where it may also be accompanied by sesamoid and periosteal fibrocartilages. It is characteristic of sites where the angle of attachment changes throughout the range of joint movement and it reduces wear and tear by dissipating stress concentration at the bony interface. There is a good correlation between the distribution of fibrocartilage within an enthesis and the levels of compressive stress. The complex interlocking between calcified fibrocartilage and bone contributes to the mechanical strength of the enthesis and cartilage-like molecules (e.g. aggrecan and type II collagen) in the ECM contribute to its ability to withstand compression. Pathological changes are common and are known as enthesopathies.  (+info)

Receptor mechanisms underlying heterogenic reflexes among the triceps surae muscles of the cat. (3/9460)

The soleus (S), medial gastrocnemius (MG), and lateral gastrocnemius (LG) muscles of the cat are interlinked by rapid spinal reflex pathways. In the decerebrate state, these heterogenic reflexes are either excitatory and length dependent or inhibitory and force dependent. Mechanographic analysis was used to obtain additional evidence that the muscle spindle primary ending and the Golgi tendon organ provide the major contributions to these reflexes, respectively. The tendons of the triceps surae muscles were separated and connected to independent force transducers and servo-controlled torque motors in unanesthetized, decerebrate cats. The muscles were activated as a group using crossed-extension reflexes. Electrical stimulation of the caudal cutaneous sural nerve was used to provide a particularly strong activation of MG and decouple the forces of the triceps surae muscles. During either form of activation, the muscles were stretched either individually or in various combinations to determine the strength and characteristics of autogenic and heterogenic feedback. The corresponding force responses, including both active and passive components, were measured during the changing background tension. During activation of the entire group, the excitatory, heterogenic feedback linking the three muscles was found to be strongest onto LG and weakest onto MG, in agreement with previous results concerning the strengths of heteronymous Ia excitatory postsynaptic potentials among the triceps surae muscles. The inhibition, which is known to affect only the soleus muscle, was dependent on active contractile force and was detected essentially as rapidly as length dependent excitation. The inhibition outlasted the excitation and was blocked by intravenous strychnine. These results indicate that the excitatory and inhibitory effects are dominated by feedback from primary spindle receptors and Golgi tendon organs. The interactions between these two feedback pathways potentially can influence both the mechanical coupling between ankle and knee.  (+info)

Glycoprotein (GP) Ib-IX-transfected cells roll on a von Willebrand factor matrix under flow. Importance of the GPib/actin-binding protein (ABP-280) interaction in maintaining adhesion under high shear. (4/9460)

Adhesion of platelets to sites of vascular injury is critical for hemostasis and thrombosis and is dependent on the binding of the vascular adhesive protein von Willebrand factor (vWf) to the glycoprotein (GP) Ib-V-IX complex on the platelet surface. A unique but poorly defined characteristic of this receptor/ligand interaction is its ability to support platelet adhesion under conditions of high shear stress. To examine the structural domains of the GPIb-V-IX complex involved in mediating cell adhesion under flow, we have expressed partial (GPIb-IX), complete (GPIb-V-IX), and mutant (GPIbalpha cytoplasmic tail mutants) receptor complexes on the surface of Chinese hamster ovary (CHO) cells and examined their ability to adhere to a vWf matrix in flow-based adhesion assays. Our studies demonstrate that the partial receptor complex (GPIb-IX) supports CHO cell tethering and rolling on a bovine or human vWf matrix under flow. The adhesion was specifically inhibited by an anti-GPIbalpha blocking antibody (AK2) and was not observed with CHO cells expressing GPIbbeta and GPIX alone. The velocity of rolling was dependent on the level of shear stress, receptor density, and matrix concentration and was not altered by the presence of GPV. In contrast to selectins, which mediate cell rolling under conditions of low shear (20-200 s-1), GPIb-IX was able to support cell rolling at both venous (150 s-1) and arterial (1500-10,500 s-1) shear rates. Studies with a mutant GPIbalpha receptor subunit lacking the binding domain for actin-binding protein demonstrated that the association of the receptor complex with the membrane skeleton is not essential for cell tethering or rolling under low shear conditions, but is critical for maintaining adhesion at high shear rates (3000-6000 s-1). These studies demonstrate that the GPIb-IX complex is sufficient to mediate cell rolling on a vWf matrix at both venous and arterial levels of shear independent of other platelet adhesion receptors. Furthermore, our results suggest that the association between GPIbalpha and actin-binding protein plays an important role in enabling cells to remain tethered to a vWf matrix under conditions of high shear stress.  (+info)

Cloning of a stretch-inhibitable nonselective cation channel. (5/9460)

A homologue of the capsaicin receptor-nonselective cation channel was cloned from the rat kidney to investigate a mechanosensitive channel. We found this channel to be inactivated by membrane stretch and have designated it stretch-inactivated channel (SIC). SIC encodes a 563-amino acid protein with putative six transmembrane segments. The cDNA was expressed in mammalian cells, and electophysiological studies were performed. SIC-induced large cation currents were found to be regulated by cell volume, with currents being stimulated by cell shrinkage and inhibited by cell swelling. Single channel analysis showed a conductance of 250 pS with cation permeability (PCl/PNa < 0.1), and the channel possessed some of the characteristics of a stretch-inactivated channel in that it was permeable to calcium, sensitive to membrane stretch, and blocked by Gd3+. Therefore, we cloned one of the mechanosensitive cation channels of mammals, which is considered to regulate Ca2+ influx in response to mechanical stress on the cell membrane.  (+info)

Distinct structural attributes regulating von Willebrand factor A1 domain interaction with platelet glycoprotein Ibalpha under flow. (6/9460)

We have used recombinant von Willebrand factor (vWF) fragments to investigate the properties regulating A1 domain interaction with platelet glycoprotein (GP) Ibalpha. One fragment, rvWF508-704, represented the main portion of domain A1 (mature subunit residues 497-716) within the Cys509-Cys695 disulfide loop. The other, rvWF445-733, included the carboxyl-terminal region of domain D3, preceding A1, and corresponded to the proteolytic fragment originally identified as the GP Ibalpha-binding site (residues 449-728). Conformational changes were induced by reduction and alkylation of the Cys509-Cys695 bond and/or exposure to acidic pH. The cyclic rvWF445-733 fragment exhibited the function of native vWF A1 domain. When immobilized onto a surface, it tethered platelets at shear rates up to 6,300 s-1 mediating low velocity translocation but not stable attachment; in solution, it exhibited limited interaction with GP Ibalpha. In contrast, fragments with perturbed conformation could not tether platelets at high shear rates but promoted stable adhesion at lower shear and bound tightly to GP Ibalpha. Only in the presence of the exogenous modulator, botrocetin, did cyclic rvWF445-733 mediate irreversible adhesion. Thus, conformational transitions in the vWF A1 domain may influence differentially the efficiency of bond formation with GP Ibalpha and the stability of binding.  (+info)

Calculation of a Gap restoration in the membrane skeleton of the red blood cell: possible role for myosin II in local repair. (7/9460)

Human red blood cells contain all of the elements involved in the formation of nonmuscle actomyosin II complexes (V. M. Fowler. 1986. J. Cell. Biochem. 31:1-9; 1996. Curr. Opin. Cell Biol. 8:86-96). No clear function has yet been attributed to these complexes. Using a mathematical model for the structure of the red blood cell spectrin skeleton (M. J. Saxton. 1992. J. Theor. Biol. 155:517-536), we have explored a possible role for myosin II bipolar minifilaments in the restoration of the membrane skeleton, which may be locally damaged by major mechanical or chemical stress. We propose that the establishment of stable links between distant antiparallel actin protofilaments after a local myosin II activation may initiate the repair of the disrupted area. We show that it is possible to define conditions in which the calculated number of myosin II minifilaments bound to actin protofilaments is consistent with the estimated number of myosin II minifilaments present in the red blood cells. A clear restoration effect can be observed when more than 50% of the spectrin polymers of a defined area are disrupted. It corresponds to a significant increase in the spectrin density in the protein free region of the membrane. This may be involved in a more complex repair process of the red blood cell membrane, which includes the vesiculation of the bilayer and the compaction of the disassembled spectrin network.  (+info)

The forward rate of binding of surface-tethered reactants: effect of relative motion between two surfaces. (8/9460)

The reaction of molecules confined to two dimensions is of interest in cell adhesion, specifically for the reaction between cell surface receptors and substrate-bound ligand. We have developed a model to describe the overall rate of reaction of species that are bound to surfaces under relative motion, such that the Peclet number is order one or greater. The encounter rate between reactive species is calculated from solution of the two-dimensional convection-diffusion equation. The probability that each encounter will lead to binding depends on the intrinsic rate of reaction and the encounter duration. The encounter duration is obtained from the theory of first passage times. We find that the binding rate increases with relative velocity between the two surfaces, then reaches a plateau. This plateau indicates that the increase in the encounter rate is counterbalanced by the decrease in the encounter duration as the relative velocity increases. The binding rate is fully described by two dimensionless parameters, the Peclet number and the Damkohler number. We use this model to explain data from the cell adhesion literature by incorporating these rate laws into "adhesive dynamics" simulations to model the binding of a cell to a surface under flow. Leukocytes are known to display a "shear threshold effect" when binding selectin-coated surfaces under shear flow, defined as an increase in bind rate with shear; this effect, as calculated here, is due to an increase in collisions between receptor and ligand with increasing shear. The model can be used to explain other published data on the effect of wall shear rate on the binding of cells to surfaces, specifically the mild decrease in binding within a fixed area with increasing shear rate.  (+info)

Cyclic mechanical stretch promotes energy metabolism in osteoblast-like cells through an mTOR signaling-associated mechanismCyclic mechanical stretch promotes energy metabolism in osteoblast-like cells through an mTOR signaling-associated mechanism
Studies have demonstrated the role mechanical stress plays in regulating osteoblastic functions, such as cellular proliferation, osteogenic differentiation, signal transduction and apoptosis (14-16,26). Energy metabolism is essential to maintaining the biological activities of osteoblasts (17). In the present study, we revealed a novel mechanism in osteoblastic mechanobiology, through which cyclic stretch promotes osteoblastic energy metabolism by increasing the expression of enzymes associated with energy metabolism, partially through the Akt/mTOR/p70s6k signaling pathway. Firstly, cyclic mechanical stretch promoted energy metabolism in the MG-63 cells, which was evidenced by the increased glucose consumption, and the increased levels of lactate, intracellular ATP, and energy metabolism-related genes (ATP5B, ATP5F1, ATP5J, F1-ATPase Ī±, LDHA and enolase 1), and ATP5B and ATP5J proteins. Secondly, cyclic mechanical stretch stimulated the activation of the Akt/mTOR/p70s6k pathway by prompting the ...
Experimental Methodology Using Digital Image Correlation to Assess Ballistic Helmet Blunt Trauma | Journal of Applied Mechanics...Experimental Methodology Using Digital Image Correlation to Assess Ballistic Helmet Blunt Trauma | Journal of Applied Mechanics...
As modern helmets have become quite capable of defeating the penetration capabilities of ballistic threats, Soldiers may experience head injuries due to blunt trauma caused by helmet back face deformation (BFD). Possible resulting injuries include skull fracture, hematoma, concussion, contusion, diffuse axonal injury, etc. Some of these injuries have been associated with traumatic brain injury. In order to assess potential injury mechanisms prior to fielding new helmets, we have developed a means to experimentally replicate and measure helmet BFD that can be correlated to injury criteria. In this study, helmet performance test methodology is developed using a digital image correlation (DIC) technique. DIC provides the capability to measure dynamic displacements, thereby providing the ability to calculate deformation, velocity, and acceleration rates. We have shown that digital image correlation is an experimentation technique that accurately captures BFD area and rate of deformation for impacts ...
Endothelial cell cytoskeletal alignment independent of fluid shear stress on micropatterned surfaces<...Endothelial cell cytoskeletal alignment independent of fluid shear stress on micropatterned surfaces<...
TY - JOUR. T1 - Endothelial cell cytoskeletal alignment independent of fluid shear stress on micropatterned surfaces. AU - Vartanian, Keri B.. AU - Kirkpatrick, Sean J.. AU - Hanson, Stephen R.. AU - Hinds, Monica. PY - 2008/7/11. Y1 - 2008/7/11. N2 - Endothelial cells (ECs) in athero-protective regions are elongated with actin and microtubule fibers aligned parallel to the direction of blood flow. Fluid shear stress (FSS) affects EC shape and functions, but little is known about shape-dependent EC properties that are independent of FSS. To evaluate these properties, ECs were elongated on micropatterned (MP) 25 Ī¼m wide collagen-coated lanes (MPECs) and characterized by cell shape index, actin and microtubule alignment, and polarization of the microtubule-organizing center (MTOC). ECs on non-patterned surfaces were also exposed to FSS. MPEC elongation was microtubule-dependent (and actin-independent); shape indices and cytoskeletal alignment were comparable to FSS-elongated ECs. Cytoskeletal ...
Arterial Remodeling Associates with CKD Progression | American Society of NephrologyArterial Remodeling Associates with CKD Progression | American Society of Nephrology
We showed that arterial remodeling evolutes overtime with an enlargement and a thinning of the carotid artery, leading to an increased carotid circumferential wall stress. This kind of arterial remodeling evolution is unusual in this high cardiovascular risk population. The pathophysiology of increased carotid circumferential wall stress is not obvious. In response to increased BP, in particular, the pulsatile component, degenerative changes, and fractures of the extracellular matrix component occur in the arterial wall, leading to arterial enlargement.14 The response to dilation is a thickening of the arterial wall, generally considered as adaptive, aiming at normalizing circumferential wall stress. We have previously shown in hypertensive patients that local pulse pressure was associated with increased diameter and intima-media thickness; however, circumferential wall stress was not fully normalized.15 In this study, we showed that this response does not occur in CKD patients and instead we ...
Effects of the local mechanical environment on vertebrate tissue differentiation during repair: does repair recapitulate...Effects of the local mechanical environment on vertebrate tissue differentiation during repair: does repair recapitulate...
The local mechanical environment is a crucial factor in determining cell and tissue differentiation during vertebrate skeletal development and repair. Unlike the basic response of bone to mechanical load, as described in Wolffs law, the mechanobiological relationship between the local mechanical environment and tissue differentiation influences everything from tissue type and molecular architecture to the formation of complex joints. This study tests the hypothesis that precisely controlled mechanical loading can regulate gene expression, tissue differentiation and tissue architecture in the adult skeleton and that precise manipulation of the defects local mechanical environment can initiate a limited recapitulation of joint tissue development. We generated tissue type predictions using finite element models (FEMs) interpreted by published mechanobiological fate maps of tissue differentiation. The experiment included a custom-designed external fixator capable of introducing daily bending, ...
Cytosolic Alkalinization of Vascular Endothelial Cells Produced by an Abrupt Reduction in Fluid Shear Stress | Circulation...Cytosolic Alkalinization of Vascular Endothelial Cells Produced by an Abrupt Reduction in Fluid Shear Stress | Circulation...
The acute and chronic adaptation to changes in blood flow occur as a result of endothelium-dependent responses that regulate vascular tone and the organization of the blood vessel wall. Among the most rapid responses of vascular endothelial cells to changes in fluid shear stress are K+ channel activation,2 generation of inositol trisphosphate,3 an increase in [Ca2+]i,23 24 and changes in pHi.4 5 The present study shows that an abrupt decrease in fluid shear stress produces cytosolic alkalinization of vascular endothelial cells by affecting membrane ion transporters that contribute to pHi regulation. After a period of exposure to continuous fluid shear stress at 2.7 dyne/cm2, the abrupt reduction of fluid shear stress from 2.7 to 0.3 dyne/cm2 produced a bicarbonate-dependent increase in pHi of 0.27 pH unit, which was not affected by prior inhibition of the Na+-H+ exchanger alone. Recovery from an NH4Cl prepulse-induced acid load occurred more rapidly when fluid shear stress was abruptly reduced ...
Regulation of Vascular Smooth Muscle Cells and Mesenchymal Stem Cells by Mechanical StrainRegulation of Vascular Smooth Muscle Cells and Mesenchymal Stem Cells by Mechanical Strain
Vascular smooth muscle cells (SMCs) populate in the media of the blood vessel, and play an important role in the control of vasoactivity and the remodeling of the vessel wall. Blood vessels are constantly subjected to hemodynamic stresses, and the pulsatile nature of the blood flow results in a cyclic mechanical strain in the vessel walls. Accumulating evidence in the past two decades indicates that mechanical strain regulates vascular SMC phenotype, function and matrix remodeling. Bone marrow mesenchymal stem cell (MSC) is a potential cell source for vascular regeneration therapy, and may be used to generate SMCs to construct tissue-engineered vascular grafts for blood vessel replacements. In this review, we will focus on the effects of mechanical strain on SMCs and MSCs, e.g., cell phenotype, cell morphology, cytoskeleton organization, gene expression, signal transduction and receptor activation. We will compare the responses of SMCs and MSCs to equiaxial strain, uniaxial strain and mechanical strain
Shear stress activation of SREBP1 in endothelial cells is mediated by integrins<...Shear stress activation of SREBP1 in endothelial cells is mediated by integrins<...
TY - JOUR. T1 - Shear stress activation of SREBP1 in endothelial cells is mediated by integrins. AU - Liu, Yi. AU - Chen, Benjamin P C. AU - Lu, Min. AU - Zhu, Yi. AU - Stemerman, Michael B.. AU - Chien, Shu. AU - Shyy, John Y J. PY - 2002/1/29. Y1 - 2002/1/29. N2 - We investigated the effect of shear stress on the sterol regulatory element-binding protein 1 (SREBP1) in vascular endothelial cells (ECs) and the mechanotransduction mechanism involved. Application of a shear stress (12 dyn/cm2) caused the proteolytic cleavage of SREBP1 and the ensuing translocation of its transcription factor domain into the nucleus. As a result, shear stress increased the mRNAs encoding the low density lipoprotein receptor (LDLR), as well as the binding of 125I-LDL. Using a step flow channel, we showed that SREBP1 activation in ECs under laminar flow is transient, but disturbed flow causes sustained activation. In studying the shear stress-elicited molecular signaling that activates SREBP1, we found that blocking ...
Mechanical regulation of macrophage function - Cyclic tensile force inhibits NLRP3 inflammasome-dependent IL-1Ī² secretion in...Mechanical regulation of macrophage function - Cyclic tensile force inhibits NLRP3 inflammasome-dependent IL-1Ī² secretion in...
TY - JOUR. T1 - Mechanical regulation of macrophage function - Cyclic tensile force inhibits NLRP3 inflammasome-dependent IL-1Ī² secretion in murine macrophages. AU - Maruyama, Kentaro. AU - Nemoto, Eiji. AU - Yamada, Satoru. PY - 2019/2/7. Y1 - 2019/2/7. N2 - Mechanical stress maintains tissue homeostasis by regulating many cellular functions including cell proliferation, differentiation, and inflammation and immune responses. In inflammatory microenvironments, macrophages in mechanosensitive tissues receive mechanical signals that regulate various cellular functions and inflammatory responses. Macrophage function is affected by several types of mechanical stress, but the mechanisms by which mechanical signals influence macrophage function in inflammation, such as the regulation of interleukin-1Ī² by inflammasomes, remain unclear. In this review, we describe the role of mechanical stress in macrophage and monocyte cell function.. AB - Mechanical stress maintains tissue homeostasis by regulating ...
Faculty Collaboration Database - Revealing the role of phosphatidylserine in shear stress-mediated protection in endothelial...Faculty Collaboration Database - Revealing the role of phosphatidylserine in shear stress-mediated protection in endothelial...
Previous studies have demonstrated that endothelial cells exposed to laminar shear stress are protected from apoptotic stimuli such as tumor necrosis factor (TNF)-alpha. The authors investigated the role of phosphatidylserine (PS) in this phenomenon. Western blot analysis of cleaved caspase 3 was used as an indicator of apoptosis and revealed that in the absence of serine, endothelial cells exposed to laminar shear stress were unable to protect against TNF-alpha-induced apoptosis, in contrast to sheared cells grown in regular medium. It was also found that shear-induced activation of the Akt pathway was significantly decreased in cells grown without serine. In addition, quantitation of PS using a novel isotopic labeling technique involving the use of formalin revealed that stearoyl-oleic PS (18:0/18:1) did not increase during shear treatment. These findings suggest that basal levels of PS are required to activate survival pathways in endothelial cells and thereby contribute to the overall ...
Abstract 588: Cap Inflammation Leads to Large Plaque Cap Stress Decrease and Strain Increase: MRI-PET/CT-Based FSI Modeling |...Abstract 588: Cap Inflammation Leads to Large Plaque Cap Stress Decrease and Strain Increase: MRI-PET/CT-Based FSI Modeling |...
Introduction: Recent studies indicated that plaque rupture may be associated with: a) extreme mechanical stress/strain conditions; b) large lipid-rich necrotic core; c) thin and weakening fibrous cap; d) cap inflammation; e) intraplaque hemorrhage. Fayad et al and others have been developing multi-modality imaging technology using PET/CT (Positron Emission Tomography/ Computed Tomography) and MRI (magnetic resonance imaging) to identify inflammation in arteries. The goal of this paper is to investigate possible impact of cap inflammation on plaque stress/strain and flow shear stress conditions.. Method: An MRI-PET/CT-based modeling approach is proposed to develop fluid-structure interaction (FSI) models for human carotid plaque assessment and quantify the effect of inflammation on plaque stress/strain conditions. The combined PET/CT and MRI data was acquired from a 74 year old male patient (with informed consent) to assess arterial inflammation. The patient was imaged with dark blood ...
E-GEOD-58389 - Cyclic mechanical stretch-induced gene expression - OmicsDIE-GEOD-58389 - Cyclic mechanical stretch-induced gene expression - OmicsDI
With gene expression profiling it was aimed to identify the differentially expressed genes associated with the regulation of the cytoskeleton to investigate the stretch-induced cell alignment mechanism. A whole genome microarray based analysis of the stretch-induced gene expression changes was done. Gene expression was measured at the beginning of the alignment process showing first reoriented cells after 5 h stretching and at the end after 24 h, where nearly all cells are aligned. Cyclic mechanical stretching of cells results in cellular alignment perpendicular to the stretch direction regulating cellular response. This stress response is assumed to be an adaptation mechanism to reduce extensive stretching but also acts as architectural restructuring changing performance and biomechanics of the tissue. Gene expression profiling of control vs. stretched primary human dermal fibroblasts after 5 h and 24 h demonstrated the regulation of differentially expressed genes associated with metabolism,
Fluid shear stress-induced reorganization of adherens junctions in hum by Jon A. Ukropec"Fluid shear stress-induced reorganization of adherens junctions in hum" by Jon A. Ukropec
Ukropec, Jon A., "Fluid shear stress-induced reorganization of adherens junctions in human endothelial cells" (1999). Theses. 24 ...
Phenotypic Changes in Rat Smooth Muscle Cells Exposed to Varying Amplitudes of Cyclic Equibiaxial Tensile StrainPhenotypic Changes in Rat Smooth Muscle Cells Exposed to Varying Amplitudes of Cyclic Equibiaxial Tensile Strain
Pattie Mathieu, Paul Cahill, Joseph Mackle, James King, Caitriona Lally, Phenotypic Changes in Rat Smooth Muscle Cells Exposed to Varying Amplitudes of Cyclic Equibiaxial Tensile Strain, UK Society of Biomaterials, Belfast, Ireland, 25th-26th June 2015 ...
Cyclic Strain Increases Protease-Activated Receptor-1 Expression in Vascular Smooth Muscle Cells | HypertensionCyclic Strain Increases Protease-Activated Receptor-1 Expression in Vascular Smooth Muscle Cells | Hypertension
Mechanical strain on the artery wall is increased up to 30% in hypertension and is postulated to play a role in vascular injury.2-5 Thrombin is concentrated in vivo at sites of vascular injury, and its effects are mediated chiefly through PAR-1.21 PAR-1 is expressed at very low levels in normal arteries but increases after vascular injury12,18,22 and is increased in the arteries of hypertensive rats.11 Thus, we hypothesized that cyclic strain administered to VSMCs in vitro would increase PAR-1 expression.. Cyclic strain increased PAR-1 mRNA and protein levels (Figures 1 and 2ā‡‘), and after 48 hours of cyclic strain, thrombin also produced a 50% increase in cell number (Figure 3). The significance of these findings is based on the opposite responses of PAR-1 expression to cyclic strain and shear stress. PAR-1 expression increases 2-fold under 20% cyclic strain for 24 hours, whereas it decreases by ā‰ˆ4-fold under shear stress (25 dyne/cm2) for 24 hours.14 Thus, mechanical forces regulate the ...
Abstract 768: Molecular Mechanism Of Inverse Agonism In Mechanical Stress-induced Activation Of Angiotensin II Type 1 Receptor ...Abstract 768: Molecular Mechanism Of Inverse Agonism In Mechanical Stress-induced Activation Of Angiotensin II Type 1 Receptor ...
The angiotensin II (AngII) type 1 (AT1) receptor is a G protein-coupled receptor that plays a crucial role in the development of load-induced cardiac hypertrophy. We previously reported that mechanical stress, the most important stimulus for cardiac hypertrophy, activates the AT1 receptor through an AngII-independent mechanism, and that this activation is inhibited by an inverse agonist candesartan. However, it remains unclear how mechanical stress activates AT1 receptor and how candesartan exerts inverse agonism. By serial studies using substituted cysteine accessibility mapping, we demonstrated that mechanical stress directly activates AT1 receptor by changing the conformation of AT1 receptor. Transmembrane (TM) VII of AT1 receptor showed a counterclockwise rotation and shift into the ligand-binding pocket in response to mechanical stretch, and candesartan suppressed this helical movement induced by stretch. Comparison of the inverse agonist activities of several AT1 receptor blockers (ARBs) ...
Influence of Turbulent Mechanical Stresses on Microorganisms | Applied Mechanics Reviews | ASME DCInfluence of Turbulent Mechanical Stresses on Microorganisms | Applied Mechanics Reviews | ASME DC
Many phenomena depend on the features of the fine-scale structure of turbulence, including its intermittency. This article discusses the problem of the turbulent "shear" in biotechnology including the effect of the shear stress on particles (cells, flocs, cells immobilized on microcarriers). Traditionally, the effect of intermittency has not been taken into account in the shear problem and the theory of isotropic turbulence introduced by Kolmogorov (1941) based on average values of the rate of kinetic energy dissipation, velocity fluctuactions, rates of strain, turbulent stresses etc. has been applied. In this paper a multifractal formalism is employed to describe intermittency; the results of multifractal approach are then compared with predictions of other models of intermittent and non-intermittent turbulence. The multifractal model of intermittent turbulence has been used to derive equations describing flow-particle interactions, including: equations describing turbulent stresses acting upon ...
Mechanical stimulation of human dermal fibroblasts regulates pro-inflammatory cytokines: potential insight into soft tissue...Mechanical stimulation of human dermal fibroblasts regulates pro-inflammatory cytokines: potential insight into soft tissue...
Soft tissue manual therapies are commonly utilized by osteopathic physicians, chiropractors, physical therapists and massage therapists. These techniques are predicated on subjecting tissues to biophysical mechanical stimulation but the cellular and molecular mechanism(s) mediating these effects are poorly understood. Previous studies established an in vitro model system for examining mechanical stimulation of dermal fibroblasts and established that cyclical strain, intended to mimic overuse injury, induces secretion of numerous pro-inflammatory cytokines. Moreover, mechanical strain intended to mimic soft tissue manual therapy reduces strain-induced secretion of pro-inflammatory cytokines. Here, we sought to partially confirm and extend these reports and provide independent corroboration of prior results. Using cultures of primary human dermal fibroblasts, we confirm cyclical mechanical strain increases levels of IL-6 and adding long-duration stretch, intended to mimic therapeutic soft tissue
3M 9920 Static Control Anti-Fatigue Mat3M 9920 Static Control Anti-Fatigue Mat
Static Control Anti-Fatigue Mat, 3M Static Control Anti-Fatigue Mats enable workers to stand comfortably for long periods while minimizing the fatigue associated with stand work. Manufacture from durable rubber, 3M Anti-Fatigue Mats consist of a
Hemodynamic Shear Stresses in Mouse Aortas. Implications for Atherogenesis | Arteriosclerosis, Thrombosis, and Vascular BiologyHemodynamic Shear Stresses in Mouse Aortas. Implications for Atherogenesis | Arteriosclerosis, Thrombosis, and Vascular Biology
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Atomistic simulation of amorphous solids and proteins at long time scalesAtomistic simulation of amorphous solids and proteins at long time scales
Although molecular dynamics (MD) simulation has been widely used to study of physical properties of nanomaterials, it suffers from a well-known time scale limitation where it cannot simulate processes that take longer than about hundreds of nanoseconds. However, many important processes in physics and materials science take place on time scales that cannot be reached by MD, and thus a key limitation of atomistic simulations is the ability to study the mechanical deformation of nanostructures at experimentally-relevant time scales. In this thesis, a new computational technique is proposed to overcome this issue. Specifically, a generic history-penalized self-learning metabasin escape (SLME) algorithm is developed which demonstrated high computational efficiency in potential energy surface exploration. The SLME method is then coupled, via transition state theory, to mechanical deformation, which enables a direct link between the externally applied strain rate and the energy barriers crossed on the ...
Upregulation of MMP-13 and TIMP-1 expression in response to mechanical strain in MC3T3-E1 osteoblastic cells | BMC Research...Upregulation of MMP-13 and TIMP-1 expression in response to mechanical strain in MC3T3-E1 osteoblastic cells | BMC Research...
Mechanical strain plays a significant role in the regulation of bone matrix turnover, which is mediated in part by matrix metalloproteinase (MMP)-13 and tissue inhibitors of matrix metalloproteinase (TIMP)-1. However, little is known about the correlation between mechanical strain and osteoblastic cell activities, including extracellular matrix (ECM) metabolism. Herein, we determined the effect of different magnitudes of cyclic tensile strain (0%, 6%, 12%, and 18%) on MMP-13 and TIMP-1 mRNA and protein expression in MC3T3-E1 osteoblasts. Furthermore, we employed specific inhibitors to examine the role of distinct signal transduction pathways known to mediate cellular responses to mechanical strain. We identified a magnitude-dependent increase in MMP-13 and TIMP-1 mRNA and protein levels in response to mechanical strains corresponding to 6%, 12%, and 18% elongation. The strain-induced increases in MMP-13 and TIMP-1 mRNA expression were inhibited by PD098059 and cycloheximide, respectively. Our results
Mechanical properties of Materials - TutionCentralMechanical properties of Materials - TutionCentral
1. Elasticity: The tendency of a material to regain its original dimensions (size and shape) upon the removal of load or force. Eg. Steel is more elastic than rubber. The ratio between tensile stress and tensile strain or Compressive stress and compressive strain is called youngs modulus of Elasticity.. Youngs Modulus of elasticity = E = Stress/Strain = Ļƒ / Īµ. Modulus of rigidity or shear modulus is the ratio of shear stress to the shear strain.. Modulus of Rigidity or Shear Modulus = Shear stress/shear strain Bulk or Volume modulus of elasticity is the ratio of normal stress to the volumetric strain.. Bulk Modulus = Normal stress/Volumetric strain 2. Plasticity: The tendency of a material to permanently deform when subjected to external load beyond the elastic limit. 3. Toughness: The ability of a material to absorb energy in plastic deformation till the point of fracture is known as toughness. Toughness is indicated by the total area under the stress strain curve up to the fracture point. ...
Tests to Evaluate the Mechanical Properties of the UreterTests to Evaluate the Mechanical Properties of the Ureter
In 1975, we started a research project for the development of microexplosion lith-otripsy. In this project, we investigated the mechanical properties of the urinary tract organs to clarify factors to prevent complications from the method. Tension and expansion tests were performed on the middle portion of the normal ureter taken from fresh cadavers in 1983.. A tension test was performed on eleven ureters in the longitudinal direction and seven in the transverse direction using a universal tensile tester. Tensile strength and maximum tensile stress in the transverse direction of the ureter were weaker than those in the longitudinal direction. Accordingly, it was presumed that ureteral injury first occurred in the transverse direction. The maximum tensile stress of the ureter was higher than that of the bladder, which was previously reported in another paper.. Expansive tests were performed on ten ureters. At the leakage point, the tensile strength and elongation ratio of the external diameter ...
Local Shear Stress and Brachial Artery Functions in End-Stage Renal Disease | American Society of NephrologyLocal Shear Stress and Brachial Artery Functions in End-Stage Renal Disease | American Society of Nephrology
This study is the first to analyze the relationship between in vivo measured shear rate and SS and structural and functional properties of a peripheral conduit artery in patients with ESRD. Patients with ESRD were characterized by outward remodeling of BA, with larger inner diameter and increased stiffness. The outward remodeling was not associated with higher blood flow but with an acceleration of age-associated changes. Whereas BA circumferential wall stress did not differ from that in control subjects, SS was reduced significantly in patients with ESRD as a result of lower shear rate and decreased WBV. Hand warming-induced SS augmentation was associated with FMD and enhanced BAC, which were significantly less pronounced in patients with ESRD, but dilation in response to GTN did not differ in control subjects and patients with ESRD. In patients with ESRD, the partial anemia correction increased SS as a result of enhanced WBV and was associated with an increased FMD and improved BAC.. Arterial ...
Mechanical deformation of vessel wall and shear stress determine the basal release of endothelium-derived relaxing factor in...Mechanical deformation of vessel wall and shear stress determine the basal release of endothelium-derived relaxing factor in...
We investigated the mechanisms that are responsible for the basal release of endothelium-derived relaxing factor (EDRF), which is likely to be identical with nitric oxide, in the intact coronary circulation. The increase in cGMP content of platelets passing through the coronary bed of the isolated rabbit heart was used as an index of EDRF release. Platelet cGMP content after passage through the heart under control conditions (flow rate of 20 ml/min) amounted to 0.50 +/- 0.10 pmol/mg protein. Inhibition of endothelial nitric oxide synthesis by 30 microM NG-nitro-L-arginine (L-NNA) reduced this amount by more than 60%. Increasing flow rate from 20 ml/min to 40 and 60 ml/min led to flow-dependent dilation as reflected by the subsequent drop in perfusion pressure after an initial rise. The flow-dependent dilation was associated with a significant increase in the normalized platelet cGMP content. L-NNA abolished completely both the flow-dependent dilation and the increase in platelet cGMP content. ...
CiteSeerX - Citation Query Focal contacts as mechanosensors: externally applied local mechanical force induces growth of focal...CiteSeerX - Citation Query Focal contacts as mechanosensors: externally applied local mechanical force induces growth of focal...
CiteSeerX - Scientific documents that cite the following paper: Focal contacts as mechanosensors: externally applied local mechanical force induces growth of focal contacts by an mDia1-dependent and ROCK-independent mechanism.
IUST.ORGIUST.ORG
The importance of fibre reinforced plastics continually increases due to the excellent mechanical properties, low material and manufacturing costs combined with significant weight reduction. Today, components are usually designed and calculated numerically by using finite element methods (FEM) to avoid expensive laboratory tests. These programs are based on material models including material specific deformation characteristics. In this research project, material models for short glass fibre reinforced plastics are presented to simulate the visco-elasto-plastic deformation behaviour. Prior to modelling specimens of the material EMS Grivory HTV-5H1, consisting of a Polyphthalamide matrix reinforced by 50wt.-% of short glass fibres, are characterized experimentally in terms of the highly time dependent deformation behaviour of the matrix material. To minimize the experimental effort, the cyclic deformation behaviour under tensile and compressive loading (R = āˆ’1) is characterized by isothermal ...
Patente US6540774 - Stent design with end rings having enhanced strength and radiopacity - Google PatentesPatente US6540774 - Stent design with end rings having enhanced strength and radiopacity - Google Patentes
An expandable stent having end rings with enhanced strength and radiopacity for implantation in a body lumen, such as an artery, is disclosed. The stent consists of a plurality of radially expandable cylindrical elements generally aligned on a common longitudinal stent axis and interconnected by one or more interconnecting members placed so that the stent is flexible in the longitudinal direction. The expandable cylindrical elements have regions which are subject to high stresses and regions subject to low stresses when the cylindrical elements are radially expanded. In order to increase the radiopacity of the stent, the width of the strut in the low stress region of the stent is designed to be wider than the width of the strut in the high stress regions. If a high radiopaque material is utilized and reduced radiopacity is desired, the width of the strut in the low stress region of the stent can be designed to be narrower than the strut width in the high stress regions. The end rings of the stent are
Mechanical Tension Modulates Local and Global Vesicle Dynamics in Neurons | SpringerLinkMechanical Tension Modulates Local and Global Vesicle Dynamics in Neurons | SpringerLink
Growing experimental evidence suggests that mechanical tension plays a significant role in determining the growth, guidance, and function of neurons. Mechanical tension in axons contributes to neurotr
On the influence of mechanical conditions on osteochondral healingOn the influence of mechanical conditions on osteochondral healing
In biomecanics the influence of mechanical conditions on healing of biological tissues as bones or soft tissues are analysed. In the frame of this work the mechanical behavior of intact and fractured bones with different bone qualities (osteoporotic versus normal) has been examined in a proximal humerus. Therefore a finite element model of the bone was constructed. It was found that the bone quality has a stronger impact on healing than the actual physiological loading condition does. Hence, for a future therapy of osteoporosis the precise density distribution of each individual bone must be considered. In a second step a biphasic, linear-elastic model for tissue differentiation was developed, where osteochondral healing was simulated by iterative calculation of the elastic modulus of Young within the joint region. By using this model it was possible to predict in which order in all regions of the joint the osteochondral healing took place. The stiffnesses of the newly differentiated tissues ...
On the influence of mechanical conditions on osteochondral healingOn the influence of mechanical conditions on osteochondral healing
In biomecanics the influence of mechanical conditions on healing of biological tissues as bones or soft tissues are analysed. In the frame of this work the mechanical behavior of intact and fractured bones with different bone qualities (osteoporotic versus normal) has been examined in a proximal humerus. Therefore a finite element model of the bone was constructed. It was found that the bone quality has a stronger impact on healing than the actual physiological loading condition does. Hence, for a future therapy of osteoporosis the precise density distribution of each individual bone must be considered. In a second step a biphasic, linear-elastic model for tissue differentiation was developed, where osteochondral healing was simulated by iterative calculation of the elastic modulus of Young within the joint region. By using this model it was possible to predict in which order in all regions of the joint the osteochondral healing took place. The stiffnesses of the newly differentiated tissues ...
The Detection of Compression-Induced Recrystallisation of Amorphous Indomethacin</em>...The Detection of Compression-Induced Recrystallisation of Amorphous Indomethacin</em>...
TY - CONF. T1 - The Detection of Compression-Induced Recrystallisation of Amorphous Indomethacin. AU - Craig, D.Q.M.. AU - Murphy, J.. AU - Kett, Victoria. AU - Reading, M.. PY - 2003/11. Y1 - 2003/11. M3 - Paper. SP - 1199. EP - 1199. T2 - AAPS Annual Meeting. Y2 - 1 November 2004 through 1 November 2004. ER - ...
Constitutive Equations for the Elastic Behavior of Polymers Based Upon Molecular Parameters.Constitutive Equations for the Elastic Behavior of Polymers Based Upon Molecular Parameters.
Using a free-energy approach introduced by Born and Huang in studying crystalline elasticity, molecular constitutive equations isothermal or adiabatic conditions were developed for elastic polymeric solids. The molecular model consists of non-spherical molecules which are dispersed throughout a random network of crosslinked chain molecules. The non-spherical molecules are assumed to possess an intramolecular separation potential involving the mean-square end-to-end chain distance and a torsional oscillation potential. These non-spherical molecules interact with each other and the network chains via physical physical entanglements and orientational-dependent secondary interactions. Explicit relationships for the number of such subchains were developed and depend upon the distribution, number functionality and chemical efficiency of the crosslink sites, and the functionality of the chain ends. The isothermal constitutive equations depend upon the statistical averages involving the various potentials and a
Shear Stress Downregulation of Platelet-Derived Growth Factor Receptor-Ī² and Matrix Metalloprotease-2 Is Associated With...Shear Stress Downregulation of Platelet-Derived Growth Factor Receptor-Ī² and Matrix Metalloprotease-2 Is Associated With...
The present study shows that SMC exposure to laminar flow, at arterial levels of shear stress, reduced PDGF-BB-directed cell migration and invasion. A major mechanism for this effect was the decrease in PDGF-RĪ² mRNA expression and protein levels, because shear-dependent inhibition of SMC migration was abolished in cells forced to overexpress PDGF-RĪ². It is of interest that diminished PDGF binding10 and mitogenic response to PDGF10 13 have also been observed in SMCs derived from the intima of injured carotid arteries, suggesting the possibility that SMC exposure to hemodynamic shear stress in vivo may be a mechanism for these effects.. A second mechanism that may contribute to the effect of shear stress to diminish SMC invasiveness across Matrigel is the decrease in MMP-2. MMPs are required for SMCs to invade a barrier constituted by ECM components,3 24 and lower MMP-2 levels without a change in TIMP-2, the main MMP-2 inhibitor,29 may account, at least in part, for the results shown in Figure ...
Processing, nanoindentation and scratch testing of alumina-coated YTZP | Boletƭn de la Sociedad EspaƱola de CerƔmica y VidrioProcessing, nanoindentation and scratch testing of alumina-coated YTZP | Boletƭn de la Sociedad EspaƱola de CerƔmica y Vidrio
High compressive stresses will be developed in the coatings while substrates will be subjected to very low tensile stresses (Table 2). In principle, compressive stresses would not lead to cracking of the coatings and the expected tensile stresses are not sufficient to originate cracking of the YTZP substrates. The observed delamination in the specimens with the thickest coatings (Fig. 1) can be attributed to the presence of high shear stresses at the interfaces. The non flat faces of the additional transverse and parallel cracks with large openings reveal that they were probably formed during sintering by a combination of stresses due to thermal expansion and sintering rate mismatches.. Cracks were not observed in the specimens with thinnest coatings (Fig. 2). Even though the necessary condition for delamination should be fulfilled due to the high shear stresses expected at the interfaces, the critical relationship to produce cracking between thickness and residual stresses proposed by Evans ...
Patient-specific three-dimensional simulation of LDL accumulation in a human left coronary artery in its healthy and...Patient-specific three-dimensional simulation of LDL accumulation in a human left coronary artery in its healthy and...
We calculate low-density lipoprotein (LDL) transport from blood into arterial walls in a three-dimensional, patient-specific model of a human left coronary artery. The in vivo anatomy data are obtained from computed tomography images of a patient with coronary artery disease. Models of the artery anatomy in its healthy and diseased states are derived after segmentation of the vessel lumen, with and without the detected plaque, respectively. Spatial shear stress distribution at the endothelium is determined through the reconstruction of the arterial blood flow field using computational fluid dynamics. The arterial endothelium is represented by a shear stress-dependent, three-pore model, taking into account blood plasma and LDL passage through normal junctions, leaky junctions, and the vesicular pathway. Intraluminal pressures of 70 and 120 mmHg are employed as the normal and hypertensive operating pressures, respectively. By applying our model to both the healthy and diseased states, we show that ...
The Response of Human Aortic Endothelial Cells in a Stenotic Hemodynamic Environment: Effect of Duration, Magnitude, and...The Response of Human Aortic Endothelial Cells in a Stenotic Hemodynamic Environment: Effect of Duration, Magnitude, and...
was observed. Intercellular adhesion molecule 1, vascular cell adhesion molecule 1, and E-selectin exhibited a sustained increase in protein expression with time. The mRNA levels of these molecules were transiently upregulated and this was followed by a decrease in expression to levels lower than static controls. Regionally, increased inflammatory marker expression was observed in regions of WSS gradients both proximal and distal to the stenosis when compared with the uniform flow regions, whereas the atheroprotective markers were expressed to a greater extent in regions of elevated WSS magnitudes. The results from the straight/tubular model cannot explain the regional variation seen in the stenosis models. This may help explain the localization of inflammatory cells at the shoulders of plaques in vivo.. ...
Wholesale and Distribution Static Control Tools and Equipment Production Equipment and MaterialsWholesale and Distribution Static Control Tools and Equipment Production Equipment and Materials
... : Germany. Manufacturer specializing in ionizing devices for wide range of industries. Products include equipment and systems
The Stats on Static Control - Paper, Film & Foil ConverterThe Stats on Static Control - Paper, Film & Foil Converter
When I was a kid, my father proved himself a powerful wizard when he magically stuck a balloon to the wall just by rubbing it on his head. Of course, I would later find out not only was it not magic, but the static electricity that was my childhood fascination can be a nightmarish problem for converters. The decision to purchase static control equipment and which equipment to purchase are choices
Effect of Mechanical Length Oscillations on Airways Smooth Muscle Reactivity and Crossbridge Cycling | Volume 2: Biomedical and...Effect of Mechanical Length Oscillations on Airways Smooth Muscle Reactivity and Crossbridge Cycling | Volume 2: Biomedical and...
Superimposition of length fluctuations on contracted ASM have shown to reduce active force and stiffness. This effect is usually attributed to disruption of the actomyosin crossbridge cycle; however no direct experimental data is available to support this hypothesis. This in vitro study investigated the effect of the mechanical strains on 1) the ASM reactivity and 2) on the actin-myosin crossbridges. Experiments were carried out on maximally contracted bovine ASM subjected to length strains at various frequency in the range from 10 to 100Hz, superimposed on normal tidal stretches (frequency 0.33Hz, amplitude 4%). An organ bath system was used to apply strains and measure the force; immunofluorescence technique was performed to assess the crossbridges. The results show that superimposed length strains increase breathing relaxation effect with an optimal effect obtained at 50Hz. The cholinergic stimulation promotes actin-myosin connection, and length stretches promote the detachment of those ...
EX-WIVES, CHEATERS, AND CRUSHING FASCIAL ADHESIONSEX-WIVES, CHEATERS, AND CRUSHING FASCIAL ADHESIONS
Ive talked at length on my site about DAVIS LAW of TISSUE DEFORMATION (HERE as well). H.G. Davis was a renowned Civil War-era surgeon who rightly realized, like Dr. Wolf did with bones before him (see links on Davis for info on Wolf), that soft tissues would remodel themselves in response to mechanical stresses put upon them. The problem is, if there arent enough of these mechanical stresses running around (or if the stresses never really change), then the tissues will inevitably shorten --- a common phenomenon that I refer to in my clinic as "TETHERING". What else do we know? If you are putting the kinds of mechanical stresses on MUSCLES and other connective tissues that Donnie and his crew are on a regular basis (LIGAMENTS, FASCIA, TENDONS, etc), said tissues are forced to adapt --- they have no choice. These adaptations are not anything novel and arent much different than the physical adaptations that occur from lifting weights or engaging in other forms of training (its known as getting ...
Crystallization of microlites and degassing during magma ascent : Constraint on fluid mechanical behavior of magma at Tenjo...Crystallization of microlites and degassing during magma ascent : Constraint on fluid mechanical behavior of magma at Tenjo...
Authors=NOGUCHI Satoshi ! TORAMARU Atsushi. Journal/Book_names=EOS ! Transactions, American Geophysical Union 2003 AGU Fall Meeting. Publish_Country=United States. volume=84. number=46 supplement. pages=F1615-F1615. Publish_year=2003. Publisher=American Geophysical Union. Language_of_Text=EN. Data_Type=SE!CO. ISSN=00963941. ID=200318352. ...
8-Mechanical Behavior - STRESS STRAIN RELATIONSHIPS IN MATERIALS Sequence of Steps to Produce Sheet Metal Giant Forge Press...8-Mechanical Behavior - STRESS STRAIN RELATIONSHIPS IN MATERIALS Sequence of Steps to Produce Sheet Metal Giant Forge Press...
View 8-Mechanical Behavior from NANO 108 at UCSD. STRESS - STRAIN ! RELATIONSHIPS! IN! MATERIALS! Sequence of Steps to Produce Sheet Metal Giant Forge Press Figure 5.4 Multi-Pass Rolling
British Library EThOS: Modelling the freezing and thawing behaviour of saturated soilsBritish Library EThOS: Modelling the freezing and thawing behaviour of saturated soils
This thesis presents an investigation of the thermo / hydro / mechanical behaviour of saturated soils with cryogenic suction effects. The flow relationships accommodate a number of mechanisms: i) heat transfer by conduction, convection, and latent heat transfer and ii) moisture transfer in the liquid phase due to pressure head, elevation head, and thermal gradients. The mechanical behaviour of the soil is modelled by an elasto-plastic work hardening modified Cam- Clay constitutive model. A numerical solution for the theoretical formulation is presented. Standard finite element methods are used for spatial discretisation and finite difference methods are used for temporal discretisation. Verification of the model is achieved by means of programme of tests to check the following cryogenic components i) coupled thermo-hydraulic response, ii) deformation behaviour of the fully coupled thermo-hydro-mechanical model, iii) transient coupled liquid flow and deformation behaviour, and iv) latent heat of ...
Mechanical and optical characterization of an anelastic polymer at large strain rates and large strains | SpringerLinkMechanical and optical characterization of an anelastic polymer at large strain rates and large strains | SpringerLink
Two constitutive relations have been determined from test results that characterize, respectively, the uniaxial and photomechanical behavior of a polyester-styrene copolymer for strain rates from 10āˆ’5...
Radial vs Axial Turbine, diff in mechanical stress | Physics Forums - The Fusion of Science and CommunityRadial vs Axial Turbine, diff in mechanical stress | Physics Forums - The Fusion of Science and Community
I am a hobbyist and I have designed a radial turbine device for use in a tidal stream. I have conducted a couple of experiments to demonstrate that there is less mechanical stress in the radial approach as compared to the axial approach but I would like to prove this concept mathematically (at a basic level). I have been able to find references to Eulers equation but (not being an engineer or physicist) am unable to figure out how to use the formula to show the difference. Can someone out there please explain the basic math principles that show why an axial turbine will have more mechanical stresses than a radial turbine ...
Strain Magnitude and Strain Rate Influence Stretch-Induced Injury of PC12 Cells | springerprofessional.deStrain Magnitude and Strain Rate Influence Stretch-Induced Injury of PC12 Cells | springerprofessional.de
The acceleration-deceleration associated with external impact to head causes the mechanical deformation of brain tissue, resulting in neuronal
The effect of cyclic mechanical strain on the expression of adhesion-related genes by periodontal ligament cells in two...The effect of cyclic mechanical strain on the expression of adhesion-related genes by periodontal ligament cells in two...
Background and Objective: Cell adhesion plays important roles in maintaining the structural integrity of connective tissues and sensing changes in the biomechanical environment of cells. The objective of the present investigation was to extend our understanding of the effect of cyclic mechanical strain on the expression of adhesion-related genes by human periodontal ligament cells. Material and Methods: Cultured periodontal ligament cells were subjected to a cyclic in-plane tensile deformation of 12% for 5s (0.2Hz) every 90s for 6-24h in a Flexercell FX-4000 Strain Unit. The following parameters were measured: (i)cell viability by the MTT assay; (ii)caspase-3 and -7 activity; and (iii)the expression of 84 genes encoding adhesion-related molecules using real-time RT-PCR microarrays. Results: Mechanical stress reduced the metabolic activity of deformed cells at 6h, and caspase-3 and -7 activity at 6 and 12h. Seventy-three genes were detected at critical threshold values <35. Fifteen showed a ...
Validation of Digital Image Correlation Techniques for Strain Measurement in Biomechanical Test Models | Summer Bioengineering...Validation of Digital Image Correlation Techniques for Strain Measurement in Biomechanical Test Models | Summer Bioengineering...
Many previous biomechanical studies of bone and bone substitutes have estimated strains in these materials using strain gages. The purpose of this study was to compare digital image correlation (DIC) strain measurements to those obtained from strain gages in order to assess the applicability of DIC technology to common biomechanical testing scenarios. Compression and bending tests were conducted on aluminum alloy, polyurethane foam, and laminated polyurethane foam specimens. Results showed no significant differences in the principal strain values (or the variances) between strain gage and DIC measurements on the aluminum alloy and laminated polyurethane foam specimens. There were significance differences between the principal strain measurements of the non-laminated polyurethane foam specimens, but the deviation from the theoretical results was similar for both measurement techniques. In summary, DIC techniques provide similar results to those obtained from strain gages and also provide full ...
Longitudinal residual strain and stress-strain relationship in rat small intestine | BioMedical Engineering OnLine | Full TextLongitudinal residual strain and stress-strain relationship in rat small intestine | BioMedical Engineering OnLine | Full Text
To obtain a more detailed description of the stress-free state of the intestinal wall, longitudinal residual strain measurements are needed. Furthermore, data on longitudinal stress-strain relations in visceral organs are scarce. The present study aims to investigate the longitudinal residual strain and the longitudinal stress-strain relationship in the rat small intestine. The longitudinal zero-stress state was obtained by cutting tissue strips parallel to the longitudinal axis of the intestine. The longitudinal residual stress was characterized by a bending angle (unit: degrees per unit length and positive when bending outwards). Residual strain was computed from the change in dimensions between the zero-stress state and the no-load state. Longitudinal stresses and strains were computed from stretch experiments in the distal ileum at luminal pressures ranging from 0-4 cmH2O. Large morphometric variations were found between the duodenum and ileum with the largest wall thickness and wall area in the
Mechanical stress-induced apoptosis of nucleus pulposus cells: An in vitro and in vivo rat model<...Mechanical stress-induced apoptosis of nucleus pulposus cells: An in vitro and in vivo rat model<...
TY - JOUR. T1 - Mechanical stress-induced apoptosis of nucleus pulposus cells. T2 - An in vitro and in vivo rat model. AU - Kuo, Yi Jie. AU - Wu, Lien Chen. AU - Sun, Jui Sheng. AU - Chen, Ming Hong. AU - Sun, Man Ger. AU - Tsuang, Yang Hwei. PY - 2014. Y1 - 2014. N2 - Background: Un-physiological loads play an important role in the degenerative process of inter-vertebral discs (IVD). In this study, we used an in vitro and in vivo rat model to investigate the mechanism of nucleus pulposus (NP) cells apoptosis induced by mechanical stress. Methods: Static compressive load to IVDs of rat tails was used as the in vivo model. For the in vitro model, NP cells were tested under the physiological and un-physiological loading. For histological examination, apoptotic index study, and apoptotic gene expression, we also selected cytokines [bone morphogenetic protein (BMP)-2/7, insulin-like growth factor (IGF)-1, platelet-derived growth factor (PDGF)] to be analyzed. Results: Under mechanical loading, ...
Converging parallel plate flow chambers for studies on the effect of the spatial gradient of wall shear stress on endothelial...Converging parallel plate flow chambers for studies on the effect of the spatial gradient of wall shear stress on endothelial...
Lu, Yiling and Li, Wei-Qi and Oraifige, I. and Wang, Wen (2014) Converging parallel plate flow chambers for studies on the effect of the spatial gradient of wall shear stress on endothelial cells. Journal of Biosciences and Medicines, 2. pp. 50-56. ISSN 2327-5081 ...
Cyclic Mechanical Stress and Trabecular Meshwork Cell Contractility | IOVS | ARVO JournalsCyclic Mechanical Stress and Trabecular Meshwork Cell Contractility | IOVS | ARVO Journals
Purpose: : In the presence of ocular pulse (2.7 mmHg/sec), outflow facility of perfused anterior segments decreases. The exact mechanism by which conventional outflow tissues respond to cyclic pressure oscillations is unknown. The aim of the present study was to test the hypothesis that trabecular meshwork (TM) cell contractility mediates outflow facility responses to cyclic mechanical stress. Methods: : We modified an Ussing chamber perfusion system to deliver cyclic pressure oscillations while monitoring intrachamber pressure in real time (an inverse indicator of contraction-mediated changes in hydraulic conductivity). Mature human TM cell monolayers on polycarbonate filters were perfused at a constant flow rate of 2.5 Āµl/min until reaching a stable baseline pressure (5-20 mmHg). Chamber contents were exchanged using DMEM (control) or compounds known to affect cell contractility (isoproterenol, Y27632, pilocarpine and nifedipine). After reaching a new baseline, monolayers were subjected to ...
Effects of fluid dynamic shear stress on platelet aggregability under pathophysiologic conditionsEffects of fluid dynamic shear stress on platelet aggregability under pathophysiologic conditions
The objective of this work was to further our understanding of the influence hemodynamic forces have on the cardiovascular system. Specifically, the effect of shear stress on platelet aggregability under two pathophysiological conditions was studied. Elevated shear stress levels in stenosed vessels induce platelet aggregation. Increased plasma catecholamine concentrations have also been implicated in the onset of acute coronary ischemic syndromes. This first study was designed to examine the synergistic platelet activation by the interaction of shear stress and epinephrine. Platelets suspensions sheared at subthreshold levels in a cone and plate viscometer showed little or no aggregation unless pretreated with subthreshold concentrations of epinephrine. Monoclonal antibody blockade of glycoproteins (Gp) Ib and IIb/IIIa showed that the synergistic platelet aggregation required functional Gp IIb/IIIa but could partially bypass Gp Ib-von Willebrand factor (vWF) interaction. Binding studies ...
Fluid mechanical shear induces structural transitions in assembly of a peptide-lipid conjugate<...Fluid mechanical shear induces structural transitions in assembly of a peptide-lipid conjugate<...
TY - JOUR. T1 - Fluid mechanical shear induces structural transitions in assembly of a peptide-lipid conjugate. AU - Shimada, Tomoko. AU - Megley, Katie. AU - Tirrell, Matthew. AU - Hotta, Atsushi. PY - 2011/10/7. Y1 - 2011/10/7. N2 - Peptide amphiphiles (PA) can self-assemble into both spherical micelles and worm-like micelles. The control of worm-like micelle formation of PA is an area of active research, most often accomplished by modulating the temperature, salt content, or pH of the environment. In this work, we demonstrate the shear-induced formation of worm-like micelles in our designed peptide amphiphile C 16-W3K. Before adding shear, the peptide amphiphiles form spherical micelles in solution and exhibit little to no viscoelasticity. As the solution is subjected to simple shear flow, with increasing shear rate, spherical micelles form rapidly into elongated worm-like micelles up to microns in length. Though it has been reported that some dilute surfactant solutions exhibit shear-induced ...
Association of remodeling with endothelial shear stress, plaque elasticity, and volume in coronary arteries: A pilot coronary...Association of remodeling with endothelial shear stress, plaque elasticity, and volume in coronary arteries: A pilot coronary...
TY - JOUR. T1 - Association of remodeling with endothelial shear stress, plaque elasticity, and volume in coronary arteries. T2 - A pilot coronary computed tomography angiography study. AU - Katranas, Sotirios A.. AU - Kelekis, Anastasios L.. AU - Antoniadis, Antonios P.. AU - Chatzizisis, Yiannis S.. AU - Giannoglou, George D.. PY - 2014/5. Y1 - 2014/5. N2 - We sought to noninvasively assess the relationship between arterial remodeling, endothelial shear stress (ESS), and wall stiffness in coronary arteries. We studied 28 coronary arteries from 22 patients undergoing coronary computed tomography angiography (CCTA). The ESS was calculated in 2-mm long segments using computational fluid dynamics. Local remodeling, plaque dimensions, and local wall stiffness were assessed in each segment. The ESS was lower in the regions of excessive expansive remodeling versus compensatory expansive versus inadequate expansive versus constrictive remodeling. Areas of decreased wall stiffness more frequently ...
Interfacing fluid shear stress with vascular oxidative stress: application of nano and micro sensors :: University of Southern...Interfacing fluid shear stress with vascular oxidative stress: application of nano and micro sensors :: University of Southern...
Fluid shear stress is an important factor to consider when studying the behavior of endothelial cells in vascular system. The main focus of this study is to relate the spatial and temporal variations in shear stress with the extent of oxidative stress, specifically in arterial branching points in comparison with straight regions in the vessels. For this purpose, a micro shear stress sensor has been designed and fabricated with the backside wire binding feature. The sensors were flush mounted in a 3-D scaled up model of carotid arterial bifurcation to measure the spatial variations in shear stress. These measurements were validated by computational fluid dynamics simulations. Arteries with complex geometries develop a low profile and bidirectional type of shear stress, namely oscillatory however unidirectional and high profile of shear stress, namely pulsatile shear stress develops at straight regions of the vessels. We compared the extent of oxidative stress for the endothelial cells which were ...
Effects of mechanical stress and carvedilol in lamin A/C-deficient dilated cardiomyopathy | Garvan Institute of Medical ResearchEffects of mechanical stress and carvedilol in lamin A/C-deficient dilated cardiomyopathy | Garvan Institute of Medical Research
RATIONALE: Mutations in the LMNA gene, which encodes the nuclear lamina proteins lamin A and lamin C, are the most common cause of familial dilated cardiomyopathy (DCM). Mechanical stress-induced apoptosis has been proposed as the mechanism underpinning DCM in lamin A/C-deficient hearts, but supporting in vivo evidence has been lacking. OBJECTIVE: Our aim was to study interventions to modify mechanical stress in heterozygous Lmna knockout (Lmna(+/-)) mice. METHODS AND RESULTS: Cardiac structure and function were evaluated before and after exercise training, thoracic aortic constriction, and carvedilol treatment. Lmna(+/-) mice develop adult-onset DCM with relatively more severe disease in males. Lmna(+/-) cardiomyocytes show altered nuclear morphology and perinuclear desmin organization, with enhanced responses to hypo-osmotic stress indicative of cytoskeletal instability. Despite these structural defects that provide a template for mechanical stress-induced damage, young Lmna(+/-) mice ...
Role of miR-146a in the Regulation of Gene Expression Changes Induced by Mechanical Stress in Trabecular Meshwork Cells | IOVS ...Role of miR-146a in the Regulation of Gene Expression Changes Induced by Mechanical Stress in Trabecular Meshwork Cells | IOVS ...
Purpose: To investigate the involvement of miR-146a in the regulation of responses induced by cyclic mechanical stress (CMS) in human trabecular meshwork (HTM) cells and its effects on intraocular pressure in vivo.. Methods: Effects of miR-146a on the responses to CMS were evaluated in cells transfected with miR-146a mimic or controls transfected with scrambled microRNA. Two primary HTM cell culture lines were incubated in triplicate on flexible bottom plates and subjected to cyclic mechanical stress (20% stretching, 1 cycle per second, during 3 hours). Non-stress parallel control cultures were incubated in similar plates under identical conditions. The effects of miR-146 inhibitor were tested in one primary HTM culture. Changes in expression for miR-146a, IL6, IL8, IL1beta, BMP2, MMP3, HSP70, IRAK1, Serpin, COX1 and COX2 were analyzed by quantitative real time PCR. Three Sprague-dawley rats were injected into the anterior chamber with influenza virus (IAV) expressing miR-146a and the ...
OSA | 4D shear stress maps of the developing heart using Doppler optical coherence tomographyOSA | 4D shear stress maps of the developing heart using Doppler optical coherence tomography
Accurate imaging and measurement of hemodynamic forces is vital for investigating how physical forces acting on the embryonic heart are transduced and influence developmental pathways. Of particular importance is blood flow-induced shear stress, which influences gene expression by endothelial cells and potentially leads to congenital heart defects through abnormal heart looping, septation, and valvulogenesis. However no imaging tool has been available to measure shear stress on the endocardium volumetrically and dynamically. Using 4D structural and Doppler OCT imaging, we are able to accurately measure the blood flow in the heart tube in vivo and to map endocardial shear stress throughout the heart cycle under physiological conditions for the first time. These measurements of the shear stress patterns will enable precise titration of experimental perturbations and accurate correlation of shear with the expression of molecules critical to heart development.. Ā©2012 Optical Society of ...
A poroviscoelastic description of fibrin gelsA poroviscoelastic description of fibrin gels
The mechanical induction of specific cell phenotypes can only be properly controlled if the local stimuli applied to the cells are known as a function of the external applied loads. Finite element analysis of the cell carriers would be one method to calculate these local conditions. Furthermore, the constitutive model of the construct material should be able to describe mechanical events known to be responsible for cell stimulation, such as interstitial fluid flow. The aim of this study was to define a biphasic constitutive model for fibrin, a natural hydrogel often used for tissue engineering but not yet thoroughly characterized. Large strain poroelastic and poroviscoelastic constitutive equations were implemented into a finite element model of a fibrin gel. The parameter values for both formulations were found by either analytically solving equivalent low strain equations, or by optimizing directly the large strain equations based on experimental stress relaxation data. No poroelastic ...
Changes of intracellular free calcium following mechanical injury in a spinal cord slice preparation.Changes of intracellular free calcium following mechanical injury in a spinal cord slice preparation.
article{181863, author = {Leybaert, Luc and DEHEMPTINNE, A}, issn = {0014-4819}, journal = {EXPERIMENTAL BRAIN RESEARCH}, language = {eng}, number = {3}, pages = {392--402}, title = {Changes of intracellular free calcium following mechanical injury in a spinal cord slice preparation.}, volume = {112}, year = {1996 ...
Transduction of compressive stress by bronchial epithelium<...Transduction of compressive stress by bronchial epithelium<...
TY - JOUR. T1 - Transduction of compressive stress by bronchial epithelium. AU - Tschumperlin, D. J.. AU - Drazen, J. M.. PY - 2002/12/1. Y1 - 2002/12/1. N2 - The epithelial lining of the asthmatic airway is exposed to compressive stress as a consequence of smooth muscle constriction. We have shown previously that in vitro compression of bronchial epithelial cells stimulates extracellular signal-regulated kinase (ERK) phosphorylation and downstream gene expression. Here we show that inhibition of signaling through the epidermal growth factor receptor (EGFR) with a tyrosine kinase inhibitor (AG1478) or a neutralizing antibody to the ligand-binding domain of the EGFR blocks compression-induced ERK phosphorylation. A metalloprotease inhibitor (Galardin) and a neutralizing antibody to heparin binding epidermal growth factor (HB-EGF), but not EGF, also attenuates the compression-induced ERK activation. Our results demonstrate that compressive activation of the ERK signaling pathway requires signaling ...
CACHE . The Effects of Mechanical Strain on the Gene Expression of Na+K+ ATPase in Sprague-Dawley Rat Aortic Smooth Muscle...CACHE . The Effects of Mechanical Strain on the Gene Expression of Na+K+ ATPase in Sprague-Dawley Rat Aortic Smooth Muscle...
The relationship of Na+K+ATPase and hypertension has been a topic of concentrated study for the past twenty years. During the onset of hypertension, an increase in Na+K+ATPase in the cellular membranes of the aortic smooth muscle cells has been found to occur. The reason for this increased manifestation of Na+K+ATPase during the beginning stages of hypertension and how the cells regulate this mechanism are still unclear. An initial stage of hypertension is the increase in blood pressure, which contracts the aortic smooth muscle cell lining. Previous in vitro studies have shown the contraction of the aortic smooth muscle cells does demonstrate this increased expression of Na+K+ATPase. The objective of this study was to begin to understand the regulation of the increased expression by beginning with mRNAs control and regulation. Using a Flexercell Strain Unit which cyclically stretches cells, the mRNA expression during 20%, 10%, and non-stretch controls were measured by analysis of Northern ...
A comparison of hyperelastic constitutive models applicable to brain and fat tissues | Journal of The Royal Society InterfaceA comparison of hyperelastic constitutive models applicable to brain and fat tissues | Journal of The Royal Society Interface
In this study, we provide a set of model examples for which we compare the values of the shear modulus under increasing compression or tension with experimental data for brain and fat tissues. The viscoelasticity of brain and adipose tissues was measured following the protocol described in [4]. The dynamic shear storage modulus Gā€² was measured as a function of time for increasing tensile or compressive strain (from 0% to 40%). Details are given in appendix A.. A hyperelastic constitutive material has a unique stress-strain relationship, independent of strain rate. However, the stress-strain response for viscoelastic materials changes with strain rate, and a strain-energy density function does not exist for these materials. Nonetheless, for many soft tissues, the shape of the nonlinear stress-strain curve is typically invariant with respect to strain rate. In this case, at fixed strain rate, the shear modulus may be captured by a nonlinear hyperelastic model (an example of this approach for fat ...
Investigation of fundamental powder flow properties of fine lactose particles following mechanical surface modification</em>...Investigation of fundamental powder flow properties of fine lactose particles following mechanical surface modification</em>...
TY - CONF. T1 - Investigation of fundamental powder flow properties of fine lactose particles following mechanical surface modification. AU - Zhou, Qi. AU - Roberts, Benjamin Armstrong. AU - Morton, David Alexander Vodden. AU - Stewart, Peter James. PY - 2008. Y1 - 2008. M3 - Other. SP - 49. EP - 51. ER - ...
Fully Coupled vs. Partially Coupled Fluid-Structure Interaction Methods for Patient-Specific Abdominal Aortic Aneurysm...Fully Coupled vs. Partially Coupled Fluid-Structure Interaction Methods for Patient-Specific Abdominal Aortic Aneurysm...
Primary among the mechanical factors linked with abdominal aortic aneurysm (AAA) rupture is peak wall stress, frequently quantified as either the maximum principal or Von Mises stress exerted along the diseased arterial wall. Intraluminal pressure, as an impinging normal force on the wall, has been hypothesized as the dominant influence on this stress and thus the majority of numerical modeling studies of AAA mechanics have focused on static computational solid stress (CSS) predictions [1,2]. Unfortunately, retrospective studies comparing the magnitude of wall stress with the failure strength of the aneurysmal wall have yet to consistently predict the outcome for patient-specific AAAs [3,4]. Previous studies have shown that hemodynamics also plays a significant role in both the biological and mechanical factors that exist within AAAs. In the present investigation, partially and fully coupled fluid-structure interaction (p-FSI and f-FSI, respectively) computations of patient-specific AAA models ...
Tensile stress evolution during the early-stage constrained sintering of Gadolinium-doped ceria films<...Tensile stress evolution during the early-stage constrained sintering of Gadolinium-doped ceria films<...
TY - JOUR. T1 - Tensile stress evolution during the early-stage constrained sintering of Gadolinium-doped ceria films. AU - Sheldon,Brian W.. AU - Nicholas,Jason D.. AU - Mandowara,Sunil. PY - 2011/1. Y1 - 2011/1. N2 - In situ measurements during the constrained sintering of Gd-doped ceria reveal tensile stresses up to āˆ¼250 MPa. These large tensile stresses are likely to contribute to the reduced densification (compared with freely sintered material) typically observed during constrained sintering. While existing models postulate that the tensile stress in a densifying constrained film cannot exceed the "sintering stress,"sigma;S, the observed tensile stresses are significantly larger than the estimated sigma;S for these materials. To explain this observation, we propose that the formation and extension of interparticle grain boundaries induce substantial tensile stresses in constrained films. A model of this phenomenon shows that converting excess surface energy to elastic strain energy can ...
Processes | Free Full-Text | A Multiwell Disc Appliance Used to Deliver Quantifiable Accelerations and Shear Stresses at Sonic...Processes | Free Full-Text | A Multiwell Disc Appliance Used to Deliver Quantifiable Accelerations and Shear Stresses at Sonic...
To mimic in vivo vibration of vocal fold cells, we studied the controllability and range of frequency, acceleration, duration, and shear stress in a new bioreactor attachment. The custom multiwell disc appliance fits into a commercially built rheometer, together termed a torsional rheometer bioreactor (TRB). Previous attachments to the TRB were capable of 50-100 Hz vibrations at relatively high strains but were limited to single-sample experiments. The TRB-multiwell disc system accommodates 20 samples in partially fluid-filled wells in an aseptic environment delivering three different acceleration conditions to different samples simultaneously. Frequency and amplitude used to calculate acceleration along with duration and shear stress were controllable and quantifiable using a combination of built-in rheometer sensors, manufacturer software, and smooth particle hydrodynamics (SPH) simulations. Computed shear stresses at the well bottom using SPH in two and three dimensions were verified with analytical
Response of mechanical properties of glasses to their chemical, thermal and mechanical histories - Aalborg Universitys...Response of mechanical properties of glasses to their chemical, thermal and mechanical histories - Aalborg University's...
TY - ABST. T1 - Response of mechanical properties of glasses to their chemical, thermal and mechanical histories. AU - Yue, Yuanzheng. N1 - An invited talk. PY - 2012. Y1 - 2012. N2 - Mechanical properties are a key factor to be considered when designing new glass compositions, optimizing glass processing parameters and defining the glass application fields. However, mechanical properties of glasses are complex values since they are influenced by many factors such as structure, surface, thermal history or excess entropy of the final glass state. Here I review recent progresses in understanding of the responses of mechanical properties of oxide glasses to the compositional variation, thermal history and mechanical deformation. The tensile strength, elastic modulus and hardness of glass fibers are dependent on the thermal history (measured as fictive temperature), tension, chemical composition and redox state. However, the fictive temperature affects the hardness of bulk glass in a complicated ...
Flow Shear Induced Changes in Membrane Fluidity: Dependence on Cell- Substrate Adhesion Strength | Bentham ScienceFlow Shear Induced Changes in Membrane Fluidity: Dependence on Cell- Substrate Adhesion Strength | Bentham Science
Title:Flow Shear Induced Changes in Membrane Fluidity: Dependence on Cell- Substrate Adhesion Strength. VOLUME: 9 ISSUE: 1. Author(s): Tamal Das, Tapas K. Maiti and Suman Chakraborty. Affiliation:Department of Mechanical Engineering, Indian Institute of Technology Kharagpur, Kharagpur-721302, India.. Keywords:Cell adhesion, Fluidization, Fluorescence recovery after photobleaching, Lipid raft, Membrane fluidity, Traction force microscopy. Abstract:Besides the internal genetic content and the chemical exchanges with external tissue environment, the physical interactions of cancer cells with its microenvironment also provide the guidelines for successful oncogenesis. During its metastatic journey from primary tumor to distant locations of body, a cancer cell is exposed to stresses of diverse origin and kind, of which fluid shear stresses of interstitial and haematogenic nature have been least studied in relation to their impact in cancer progression. Here, we have designed a biomicrofluidic system ...
The effects of mechanical stress and spectral shading on the growth and allocation of ten genotypes of a stoloniferous plantThe effects of mechanical stress and spectral shading on the growth and allocation of ten genotypes of a stoloniferous plant
Background and Aims Because plants protect each other from wind, stand density affects both the light climate and the amount of mechanical stress experienced by plants. But the potential interactive effects of mechanical stress and canopy shading on plant growth have rarely been investigated and never in stoloniferous plants which, due to ... read more their creeping growth form, can be expected to respond differently to these factors than erect plants. ā€  Methods Plants of ten genotypes of the stoloniferous species Potentilla reptans were subjected to two levels of mechanical stress (0 or 40 daily flexures) and two levels of spectral shading (15 % of daylight with a red : far red ratio of 0.3 vs. 50 % daylight and a red : far red ratio of 1.2). ā€  Key Results Mechanically stressed plants produced more leaves with shorter more flexible petioles, more roots, and more but less massive stolons. Responses to spectral shading were mostly in the opposite direction to thigmomorphogenesis, including ...
Biofilm FormationBiofilm Formation
Overview. Bacterial adhesion and subsequent colonization of surfaces are the first steps toward forming biofilms, which are a major concern for implanted medical devices and in many diseases. Biofilms are resistant to innate host defences, mechanical removal and antibiotic treatments. It is therefore important to understand the physiological environment and mechanisms that lead to the spread of bacteria. Experimental conditions of biofilm formation on cardiovascular stents, tubing, different surfaces and in the intestines can easily be studied using Cellixs microfluidic pumps and biochips. The dimensions of the biochips facilitate both high and low shear stress conditions. The microcapillary walls of Cellixs biochips may be pre-coated with proteins of interest to promote adhesion and culture of biofilms under different shear stress conditions. Once the biofilm is cultured, it is then possible to flow different substances (e.g. antibiotics) over the biofilm to investigate detachment. There are ...
Mechanical stress-induced mast cell degranulation activates TGF-Ī²1 signalling pathway in pulmonary fibrosis | ThoraxMechanical stress-induced mast cell degranulation activates TGF-Ī²1 signalling pathway in pulmonary fibrosis | Thorax
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nanoHUB.org - Resources: [Illinois] Peptide Release from the Cells of the Dorsal Root Ganglion upon Application of Tensile...nanoHUB.org - Resources: [Illinois] Peptide Release from the Cells of the Dorsal Root Ganglion upon Application of Tensile...
Morphological and electrophysiological studies have shown that neurons respond to specific mechanical environments. However, studies linking specific neuropeptide release based on changes in the mechanical environment are lacking. To further study the effect of mechanical stress on the cells of the nervous system, DRG cells isolated from Sprague-Dawley rats have been cultured on a mechanical stress platform which is then subjected to 20% tensile strain. To study the chemical peptide profile...
Evaluation of the Local Chloride Concentration and the Local Mechanical Stresses in Intergranular Damages Grown on a 2024...Evaluation of the Local Chloride Concentration and the Local Mechanical Stresses in Intergranular Damages Grown on a 2024...
The corrosion behavior of a 2024 T351 aluminum alloy exposed to a chloride solution was studied in the present paper. The work was focused on the effect of an environmental and thermal cyclic exposure to corrosive media and aimed to identify the main parameters explaining the changes observed between continuous and cyclic immersion tests. Optical and scanning electron microscope observations showed an increase of the intergranular corrosion damage with the extension of the corrosion from the grain boundaries to the subgrain boundaries for samples exposed to cyclic tests. An experimental set-up, including a laser beam, allowed mechanical stresses induced by the solidification of the electrolyte trapped in the corrosion damage during exposure to negative temperatures to be revealed and the chloride concentration of the electrolyte to be determined. Results were helpful in proposing corrosion mechanism during thermal and environmental cyclic exposure to chloride solutions. ...
Determine equivalent maximum shear stress in spring, Mechanical EngineeringDetermine equivalent maximum shear stress in spring, Mechanical Engineering
Mechanical Engineering Assignment Help, Determine equivalent maximum shear stress in spring, Determine equivalent maximum shear stress in spring: A close coiled helical spring contains a stiffness of 10 N/mm. Its length while fully compressed, with adjacent coils touching each other is 400 mm. G = 80 GPa. (a) Find out the wire diamet
Tensile response of ductile Ī±-titanium at moderately high strain rates | ScholarBank@NUSTensile response of ductile Ī±-titanium at moderately high strain rates | [email protected]
The tensile behavior of Grade 2 Ī±-titanium is characterized for static loading and at moderately high strain rates (200-1000 s-1). An experimental method is proposed to introduce sufficiently long tensile pulses to induce fracture in ductile specimens by incorporating a sacrificial fracture piece of adequately large diameter into a pendulum-driven tensile Kolsky bar. It is established that flow stress increases with strain rate. Necking in Ī±-titanium occurs much earlier at high strain rates compared to static loading and results in significantly smaller necking and fracture strains. An equation describing the influence of strain rate and temperature softening on necking (tensile instability) is derived. The true stress-strain response between necking and fracture is estimated by measuring the final reduction in cross-sectional area. Fracture in specimens was observed using an optical microscope, which revealed typical ductile fracture characteristics. Ā© 2001 Elsevier Science Ltd. All rights ...
Fachgebiet Bodenkunde: PublikationenFachgebiet Bodenkunde: Publikationen
Horn, R., Peth, S., & Baumgarten, W. 2012. Development of soil structure and functions: How can mechanical and hydraulic approaches contribute to quantify soil structure dynamics? Soil and Tillage Research 125, 1-2. Mordhorst, A., Zimmermann, I., Peth, S., & Horn, R. 2012. Effect of hydraulic and mechanical stresses on cyclic deformation processes of a structured and homogenized silty Luvic Chernozem. Soil and Tillage Research 125, 3-13. Baba, H.O., & Peth, S. 2012. Large scale soil box test to investigate soil deformation and creep movement on slopes by Particle Image Velocimetry (PIV). Soil and Tillage Research 125, 38-43. Holthusen, D., Haas, C., Peth, S., & Horn, R. 2012. Are standard values the best choice? A critical statement on rheological soil fluid properties viscosity and surface tension. Soil and Tillage Research 125, 61-71 Holthusen, D., Peth, S., Horn, R., & KĆ¼hn, T. 2012. Flow and deformation behavior at the microscale of soils from several longā€term potassium fertilization ...
Tectonic stress fieldTectonic stress field
We use a 2 dimensional finite element model with heterogeneous elastic strengths in continental areas to model the regional stress field orientation and relative magnitudes in and around India for 33 Ma, 20 Ma and the present day. The large-scale geological structure of India is embedded in our model by using published outlines of cratons, fold belts and basins, associated with estimates of their relative strengths, enabling the modelling of stress field deflections along interfaces between relatively strong and weak tectonic elements through time. ā€¦ Read moreā€¦. ...
Effects of the local mechanical environment on vertebrate tissue differentiation during repair: does repair recapitulate...Effects of the local mechanical environment on vertebrate tissue differentiation during repair: does repair recapitulate...
The results of this study confirm that an empirical relationship exists between the mechanical environment and gene expression, tissue formation and tissue architecture within a mechanically stimulated healing bone defect. The analyses of tissue types and their molecular architecture verify that mechanical intervention influences tissue repair and that some aspects of early development can be recapitulated within a healing adult defect. It also suggests that the repair process for virtually all skeletal tissues can be manipulated towards desirable outcomes based on precise mechanical intervention.. The FEMs accurately predicted the production and persistence of cartilage within the defects and went as far as to predict the presence of fibrous tissues in specific areas of both the bending and shear models. The mechanical stimulations created uniform cartilage bands across the entire defects that persisted well past the timeframe of bony bridging found in the controls. The bending model predicted ...
Patent US6086562 - Disposable automatic injection device - Google PatentsPatent US6086562 - Disposable automatic injection device - Google Patents
An automatic injection device includes a drug-filled vessel having a flexible membrane over a first opening thereof and a puncturable seal in a wall thereof, a hollow needle attached at a first end to the flexible membrane and having a sharp end positioned proximate the puncturable seal housing. A pressure source such as a combustible propellant provides a compressed gas above the flexible membrane to force the membrane into the drug-filled vessel, forcing the hollow needle through the puncturable seal and the drug contained in the vessel through the hollow needle. After the drug has been substantially evacuated from the vessel, the membrane is allowed to return to its pre-expanded state thus retracting the hollow needle into the vessel. Preferably, the flexible membrane is an elastomeric material having a plurality of concentrically configured corrugations to allow expansion of the membrane into the vessel. The inner surface of the vessel may have a dome-like shape such that expansion of the membrane
Cancer blog - Marc Lacroix - Le blogue du cancer: Focus: Causes, consequences, and remedies for growth-induced solid stress in...Cancer blog - Marc Lacroix - Le blogue du cancer: Focus: Causes, consequences, and remedies for growth-induced solid stress in...
The presence of growth-induced solid stresses in tumors has been suspected for some time, but these stresses were largely estimated using mathematical models. Solid stresses can deform the surrounding tissues and compress intratumoral lymphatic and blood vessels. Compression of lymphatic vessels elevates interstitial fluid pressure, whereas compression of blood vessels reduces blood flow. Reduced blood flow, in turn, leads to hypoxia, which promotes tumor progression, immunosuppression, inflammation, invasion, and metastasis and lowers the efficacy of chemo-, radio-, and immunotherapies. Thus, strategies designed to alleviate solid stress have the potential to improve cancer treatment. However, a lack of methods for measuring solid stress has hindered the development of solid stress-alleviating drugs. Here, we present a simple technique to estimate the growth-induced solid stress accumulated within animal and human tumors, and we show that this stress can be reduced by depleting cancer cells, ...
The role of ischemia and deformation in the onset of compression-induced deep tissue injury: MRI-based studies in a rat model -...The role of ischemia and deformation in the onset of compression-induced deep tissue injury: MRI-based studies in a rat model -...
A rat model was used to distinguish between the different factors that contribute to muscle tissue damage related to deep pressure ulcers that develop after compressive loading. The separate and combined effects of ischemia and deformation were studied. Loading was applied to the hindlimb of rats for 2 h. Muscle tissue was examined using MR imaging (MRI) and histology. An MR-compatible loading device allowed simultaneous loading and measurement of tissue status. Two separate loading protocols incorporated uniaxial loading, resulting in tissue compression and ischemic loading. Uniaxial loading was applied to the tibialis anterior by means of an indenter, and ischemic loading was accomplished with an inflatable tourniquet. Deformation of the muscle tissue during uniaxial loading was measured using MR tagging. Compression of the tissues for 2 h led to increased T2 values, which were correlated to necrotic regions in the tibialis anterior. Perfusion measurements, by means of contrast-enhanced MRI, ...
Patent US8043336 - Posterior vertebral support assembly - Google PatentsPatent US8043336 - Posterior vertebral support assembly - Google Patents
The invention concerns an assembly (1) comprising an interspinous wedge (5) configured to be inserted between the spinous processes (9) of two vertebrae (2) to be treated, whereof at least one zone designed to be placed between the spinous processes of the vertebrae is made of an elastically deformable material. The assembly (1) further comprises: two compressive lateral elements (6), designed to be placed on either side of the wedge (5) in the longitudinal direction, said compressive lateral elements (6) being deformable between releasing positions, wherein they are relatively spaced apart from the wedge (5) in the transverse direction, and compressive positions, wherein they are relatively close to the wedge (5) in the transverse direction; and two lateral transmission elements (7), placed between the compressive lateral elements (6) and the wedge (5), configured to press against the wedge (5) in the transverse direction thereof, at the interspinous zone (10) of the wedge (5).
Frontiers | Cyclic Stretch Alters Vascular Reactivity of Mouse Aortic Segments | PhysiologyFrontiers | Cyclic Stretch Alters Vascular Reactivity of Mouse Aortic Segments | Physiology
Large, elastic arteries buffer the pressure wave originating in the left ventricle and are constantly exposed to higher amplitudes of cyclic stretch (10%) than muscular arteries (2%). As a crucial factor for endothelial and smooth muscle cell function, cyclic stretch has, however, never been studied in ex vivo aortic segments of mice. To investigate the effects of cyclic stretch on vaso-reactivity of mouse aortic segments, we used the Rodent Oscillatory Tension Set-up to study Arterial Compliance (ROTSAC). The aortic segments were clamped at frequencies of 6-600 bpm between two variable preloads, thereby mimicking dilation as upon left ventricular systole and recoiling as during diastole. The preloads corresponding to different transmural pressures were chosen to correspond to a low, normal or high amplitude of cyclic stretch. At different time intervals, cyclic stretch was interrupted, the segments were afterloaded and isometric contractions by Ī±1-adrenergic stimulation with 2 Ī¼M phenylephrine in the
Finite Element Methods for Maxwells Equations - Oxford ScholarshipFinite Element Methods for Maxwell's Equations - Oxford Scholarship
Since the middle of the last century, computing power has increased sufficiently that the direct numerical approximation of Maxwells equations is now an increasingly important tool in science and engineering. Parallel to the increasing use of numerical methods in computational electromagnetism, there has also been considerable progress in the mathematical understanding of the properties of Maxwells equations relevant to numerical analysis. The aim of this book is to provide an up-to-date and sound theoretical foundation for finite element methods in computational electromagnetism. The emphasis is on finite element methods for scattering problems that involve the solution of Maxwells equations on infinite domains. Suitable variational formulations are developed and justified mathematically. An error analysis of edge finite element methods that are particularly well suited to Maxwells equations is the main focus of the book. The analysis involves a complete justification of the discrete de Rham
How do muscle and tendon connections last a lifetime? | EurekAlert! Science NewsHow do muscle and tendon connections last a lifetime? | EurekAlert! Science News
Muscles are connected to tendons to power animal movements such as running, swimming or flying. During development, these muscle-tendon attachments must be established such that they resist high mechanical forces for the entire life of the animal. An international research team from Marseille (France), MĆ¼nster and Munich (both Germany) shows now in fruit flies how a protein controls mechanical stress on muscle-tendon connections. The study has been published in the journal PLOS Biology.
NAFEMS Practical Introduction to Finite Element Analysis engineering analysis and simulation - FEA, Finite Element Analysis,...NAFEMS Practical Introduction to Finite Element Analysis engineering analysis and simulation - FEA, Finite Element Analysis,...
Practical Introduction to Finite Element Analysis 3-Day Training Course An opportunity to ensure that your organization gets maximum benefit from using Finit Element Analysis. FEA has become widely used and universally accepted in many industry sectors. Finite Element Analysis is a powerful technique, able to produce solutions to challenging structural analysis problems. The technology and computational efficiency of the method, together with the rapid increases in computer processi
Biaxial Failure Behavior of Bovine Tibial Trabecular Bone | Journal of Biomechanical Engineering | ASME DCBiaxial Failure Behavior of Bovine Tibial Trabecular Bone | Journal of Biomechanical Engineering | ASME DC
The biaxial yield strains for two specimens of bovine tibial trabecular bone. The arrow represents the loading direction in strain space. The angle Īø was varied in increments of 22.5Ā° for specimen 1 and 45Ā° degrees for specimen 2. The out-of-plane strains were constrained to zero and there were no shear strains. For each angle, there are two yield points plotted, one from the on-axis stress-strain curve, and the other from the transverse stress-strain curve. Only one point is plotted along some loading directions because loading was stopped before reaching the second 0.2% offset point. The elliptical curves are least squares fits to the data for Specimen 1. The solid curve fits the on-axis yield points, and the dashed curve the transverse yield points. For both curves, the sum of squared errors was less than 0.5% of the total sum of squares (R2=0.99). Yielding occurs when the strain lies outside of either of the ellipses ...
Liverpool Life Sciences UTC Innovation Labs: Bouncing back to the UTC: rubber, early molecule for SeptemberLiverpool Life Sciences UTC Innovation Labs: Bouncing back to the UTC: rubber, early molecule for September
As a final point for discussion in a tutorial, one of the most familiar properties of rubber polymers is their elasticity: i.e. rubber can be reversibly stretched. When you stretch an elastic band it gets hot, when you let go, the rubber cools. The "ground state", or unstretched polymer chains, when relaxed are disordered (recall the second law of thermodynamics), however as they are stretched, the polymer chains align, becoming more organised, relative to the unstretched, ground state, thereby reducing entropy. As a result, heat is released. Stretching requires a physical input of energy and is a relatively slow process: snapping back to the ground state, on the other hand, is spontaneous. In kinetic terms, this provides a great example of the "power" of entropy, oh and it also provides food for kinetic thought too! Finally, the the sustainable and reversible elasticity of rubber is improved by vulcanisation: can this help us understand and explain the role of disulphide bonds in protein ...
All Faculty | Duke Mechanical Engineering and Materials ScienceAll Faculty | Duke Mechanical Engineering and Materials Science
Nitric oxide (NO) and leukotrienes regulate a variety of processes in joint tissues and are frequently elevated in arthritis. Mechanical stress can induce biochemical and functional changes in cartilage that may influence mediator production. To investigate the relationship between mechanical stress and the production of leukotriene B(4) (LTB(4)) and NO, explants of porcine articular cartilage were subjected to mechanical compression for 1 h followed by 23 h recovery in the presence or absence of the NOS2 inhibitor 1400W. Dynamic compression significantly increased LTB(4) and LOX protein production in the presence of 1400W. The induced LTB(4) was functional as evidenced by its ability to promote chemotaxis of RBL-2H3 cells expressing the LTB(4) receptor. Increased LOX protein but not LTB(4) occurred in response to compression alone. These findings provide a direct link between mechanical stress and inflammation in cartilage and may have implications in the pathogenesis and treatment of ...
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Hard disk drive failureHard disk drive failure
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HyperalgesiaStress, MechanicalMechanical ProcessesBiomechanical PhenomenaMechanical PhenomenaRespiration, ArtificialMechanotransduction, CellularElasticityPhysical StimulationTensile StrengthElastic ModulusVentilators, MechanicalIsraelEritreaMotorcyclesUnited StatesFatsTooth PreparationWireless TechnologyPublicationsComputer Communication NetworksTelemetryCongresses as TopicSemiconductorsSodium HypochloritePatents as TopicColloidsSilicon DioxideCrystallizationIron Carbonyl CompoundsCytoskeletonCell NucleusModels, BiologicalSignal TransductionYogaChromatinStress, PhysiologicalStress, PsychologicalMortality, PrematureRestraint, PhysicalSyndecan-4MyofibroblastsSyndecan-1Cell DifferentiationSyndecan-2FibroblastsFinite Element AnalysisMicrotechnologyMicro-Electrical-Mechanical SystemsNanowiresEpithelioid CellsComputer Simulation
Radial vs Axial Turbine, diff in mechanical stress | Physics Forums - The Fusion of Science and CommunityRadial vs Axial Turbine, diff in mechanical stress | Physics Forums - The Fusion of Science and Community
Abstract 768: Molecular Mechanism Of Inverse Agonism In Mechanical Stress-induced Activation Of Angiotensin II Type 1 Receptor ...Abstract 768: Molecular Mechanism Of Inverse Agonism In Mechanical Stress-induced Activation Of Angiotensin II Type 1 Receptor ...
8-Mechanical Behavior - STRESS STRAIN RELATIONSHIPS IN MATERIALS Sequence of Steps to Produce Sheet Metal Giant Forge Press...8-Mechanical Behavior - STRESS STRAIN RELATIONSHIPS IN MATERIALS Sequence of Steps to Produce Sheet Metal Giant Forge Press...
Mechanical deformation of vessel wall and shear stress determine the basal release of endothelium-derived relaxing factor in...Mechanical deformation of vessel wall and shear stress determine the basal release of endothelium-derived relaxing factor in...
Influence of Turbulent Mechanical Stresses on Microorganisms | Applied Mechanics Reviews | ASME DCInfluence of Turbulent Mechanical Stresses on Microorganisms | Applied Mechanics Reviews | ASME DC
Long-term stability of EAPs under high electrical and mechanical stress - PhDpositionLong-term stability of EAPs under high electrical and mechanical stress - PhDposition
Mechanical stress modulates bone remodeling signals | SpringerLinkMechanical stress modulates bone remodeling signals | SpringerLink
How cells protect themselves against mechanical stress | EurekAlert! Science NewsHow cells protect themselves against mechanical stress | EurekAlert! Science News
When mechanical stress alters developmental gene expressionWhen mechanical stress alters developmental gene expression
Endogenous patterns of mechanical stress are required for branching morphogenesis. - PubMed - NCBIEndogenous patterns of mechanical stress are required for branching morphogenesis. - PubMed - NCBI
Fat Cells and Their Response to Mechanical StressFat Cells and Their Response to Mechanical Stress
Analysis on thermo-mechanical stress of thermoelectric module - IEEE Conference PublicationAnalysis on thermo-mechanical stress of thermoelectric module - IEEE Conference Publication
From SmƩagol to Gollum: Mechanical Stress and Bone RemodellingFrom SmƩagol to Gollum: Mechanical Stress and Bone Remodelling
Patent US5137544 - Stress-free chemo-mechanical polishing agent for II-VI compound ... - Google PatentsPatent US5137544 - Stress-free chemo-mechanical polishing agent for II-VI compound ... - Google Patents
Cells | Free Full-Text | Under Pressure: Mechanical Stress Management in the NucleusCells | Free Full-Text | Under Pressure: Mechanical Stress Management in the Nucleus
Mechanical stress affects our chromatinMechanical stress affects our chromatin
NIOSHTIC-2 Publications Search - 00181265 - Back injuries: mechanical stresses in the human spine.NIOSHTIC-2 Publications Search - 00181265 - Back injuries: mechanical stresses in the human spine.
Abstract 10698: Syndecan-4 Regulates Myofibroblast Differentiation Following Mechanical Stress | CirculationAbstract 10698: Syndecan-4 Regulates Myofibroblast Differentiation Following Mechanical Stress | Circulation
Dynamics of mechanical signal transmission through prestressed stress fibers.Dynamics of mechanical signal transmission through prestressed stress fibers.
Mechanical and electromagnetic induction of protection against oxidative stressMechanical and electromagnetic induction of protection against oxidative stress
The Airways Mechanical Stress in Lung Disease: Implications for COPD Pathophysiology and Treatment EvaluationThe Airways' Mechanical Stress in Lung Disease: Implications for COPD Pathophysiology and Treatment Evaluation
Mechanical stress in Arabidopsis leaves orients microtubules in a continuous supracellular pattern. - PubMed - NCBIMechanical stress in Arabidopsis leaves orients microtubules in a 'continuous' supracellular pattern. - PubMed - NCBI
Mechanical Stress Downregulates MHC Class I Expression on Human Cancer Cell MembraneMechanical Stress Downregulates MHC Class I Expression on Human Cancer Cell Membrane
Reference] EFFECT OF OXIDATION STRESS ON THE MECHANICAL PROPERTY OF HUMAN HAIRReference] EFFECT OF OXIDATION STRESS ON THE MECHANICAL PROPERTY OF HUMAN HAIR
A parameterized analysis of the mechanical stress for co-ronary plaque fibrous capsA parameterized analysis of the mechanical stress for co-ronary plaque fibrous caps
Stresses in oxidized claddings and mechanical stability of oxide scales (Computer file, 2006) [WorldCat.org]Stresses in oxidized claddings and mechanical stability of oxide scales (Computer file, 2006) [WorldCat.org]
Ī²-Arrestin-Biased Agonism of the Angiotensin Receptor Induced by Mechanical Stress | Science SignalingĪ²-Arrestin-Biased Agonism of the Angiotensin Receptor Induced by Mechanical Stress | Science Signaling
Influence of photo-initiator concentration on residual mechanical stress in SU-8 thin filmsInfluence of photo-initiator concentration on residual mechanical stress in SU-8 thin films
Electrothermal mechanical stress reference design flow for printed circuit boards - The Engineer The EngineerElectrothermal mechanical stress reference design flow for printed circuit boards - The Engineer The Engineer
Immune response and mechanical stress susceptibility in diseased oysters, Crassostrea virginica | SpringerLinkImmune response and mechanical stress susceptibility in diseased oysters, Crassostrea virginica | SpringerLink
Epidermal-specific deletion of CD44 reveals a function in keratinocytes in response to mechanical stressEpidermal-specific deletion of CD44 reveals a function in keratinocytes in response to mechanical stress
Frontiers | Inflammation and Mechanical Stress Stimulate Osteogenic Differentiation of Human Aortic Valve Interstitial Cells |...Frontiers | Inflammation and Mechanical Stress Stimulate Osteogenic Differentiation of Human Aortic Valve Interstitial Cells |...
Mechanical Stress Effects on the Cardiovascular Adaptations of Peripheral Arterial Calcifications Among Athletes - Full Text...Mechanical Stress Effects on the Cardiovascular Adaptations of Peripheral Arterial Calcifications Among Athletes - Full Text...
Inventions | Free Full-Text | Influence of the Grinding Wheel Topography on the Thermo-Mechanical Stress Collective in GrindingInventions | Free Full-Text | Influence of the Grinding Wheel Topography on the Thermo-Mechanical Stress Collective in Grinding
AnatomyDiseasesChemicals and DrugsAnalytical, Diagnostic and Therapeutic Techniques and EquipmentPsychiatry and PsychologyPhenomena and ProcessesDisciplines and OccupationsAnthropology, Education, Sociology and Social PhenomenaTechnology, Industry, AgricultureHumanitiesInformation ScienceHealth CareGeographicals
HyperalgesiaStress, MechanicalMechanical ProcessesBiomechanical PhenomenaMechanical PhenomenaRespiration, ArtificialMechanotransduction, CellularElasticityPhysical StimulationTensile StrengthElastic ModulusVentilators, MechanicalIsraelEritreaMotorcyclesUnited StatesFatsTooth PreparationWireless TechnologyPublicationsComputer Communication NetworksTelemetryCongresses as TopicSemiconductorsSodium HypochloritePatents as TopicColloidsSilicon DioxideCrystallizationIron Carbonyl CompoundsCytoskeletonCell NucleusModels, BiologicalSignal TransductionYogaChromatinStress, PhysiologicalStress, PsychologicalMortality, PrematureRestraint, PhysicalSyndecan-4MyofibroblastsSyndecan-1Cell DifferentiationSyndecan-2FibroblastsFinite Element AnalysisMicrotechnologyMicro-Electrical-Mechanical SystemsNanowiresEpithelioid CellsComputer Simulation
StrainsStrainOrthodontic tooth movementBoneInducesRadialEffectCompressive residual stressesStimuliCyclic mechanical stressResidualShear stressesThermo-mechanical stressTissuesPiping DesignActivatesFinite elementLocal stressesInternal stressesExertInfluenceDifferentiationRelaxationElasticityMetabolismCellsGenesANSYS MechanicalContractilityMechanismsElasticVivoEndureMeasurementTemperatureDetrimentalArabidopsisEngineersTurbulentEmbryosTriggersSignificantlyEpithelialAdaptationResponsesTurbineCytoskeletonMediatesRatsLess mechanical stressSignaling
Strains1
Strain9
Orthodontic tooth movement1
Bone1
Induces1
  • Citation Query Focal contacts as mechanosensors: externally applied local mechanical force induces growth of focal contacts by an mDia1-dependent and ROCK-independent mechanism. (psu.edu)
Radial2
  • I have conducted a couple of experiments to demonstrate that there is less mechanical stress in the radial approach as compared to the axial approach but I would like to prove this concept mathematically (at a basic level). (physicsforums.com)
  • Can someone out there please explain the basic math principles that show why an axial turbine will have more mechanical stresses than a radial turbine? (physicsforums.com)
Effect1
Compressive residual stresses4
Stimuli13
  • A key player in this process is an ion channel in the skin's inner cell membranes that was only discovered seven years ago: Piezo2 responds to mechanical stimuli by opening when the cell membrane surrounding it expands. (eurekalert.org)
  • Until now, the assumption was that Piezo1 and Piezo2 reacted solely to mechanical stimuli - perhaps because of the unique structure of the two ion channels, which is fundamentally different to that of classical voltage-gated channels. (eurekalert.org)
  • When the membrane voltage is normal, which in most cells is ?60 mV, around 95 percent of all the Piezo channels are closed and remain closed even when exposed to mechanical stimuli," explains Lewin. (eurekalert.org)
  • This importance of voltage regulation is not only demonstrated by the fact that it has clearly existed for well over 100 million years, but Moroni also discovered a mutation in the Piezo1 channels of human blood cells that alters the voltage dependence of these ion channels, making them far more sensitive to changes in the membrane potential and thus more sensitive to mechanical stimuli. (eurekalert.org)
  • His new computer model takes slices of laser confocal microscopy images of cells and reconstructs a whole, virtual version of an individual cell, allowing researchers to evaluate how that cell will respond to different mechanical stimuli. (medindia.net)
  • This link between EM field exposures and mechanical vibration is consistent with the hypothesis that cells sense these stimuli via a similar mechanism involving counter ion displacement. (nih.gov)
  • The role of mechanical stimuli in airway remodelling has been hypothesized by Tschumperlin and Drazen more than a decade ago [ 2 ]. (hindawi.com)
  • The profibrotic environment produced by mechanical stress applied to the airway epithelial cells, in the absence of any inflammatory response, demonstrated the role of mechanical stimuli in airway remodelling [ 2 ]. (hindawi.com)
  • 1 2 The exact mechanism by which trabecular outflow tissues sense and respond to different types of mechanical stimuli (i.e., elevated intraocular pressure, circadian rhythm, ocular pulse, shear flow) is not well understood. (arvojournals.org)
  • The response of plants to mechanical stimuli can also be more discrete without any apparent overt changes. (biomedcentral.com)
  • This disparity has led to our hypothesis that chondrocyte proliferation is accelerated by mechanical stimuli above natural growth. (semanticscholar.org)
  • Although mechanical stimuli are essential for the chondrocyte metabolism, excessive mechanical force contributes to the release of inflammatory mediators leading the cartilage destruction under the arthritic condition. (biomedcentral.com)
  • According to our knowledge, this is the first comprehensive review on participation of plant GRPs in the response to diverse stress stimuli. (frontiersin.org)
Cyclic mechanical stress6
Residual24
Shear stresses2
  • The data indicate that there was not much difference in the damage levels between high and low metastatic sub-lines and that a considerable fraction of stressed cells were not lethally damaged even at bulk shear stresses as high as 900 dynes/cm$\sp2$ for 5 min. (rice.edu)
  • In particular, we show that the temporal correlation function of shear stresses can be used to define an effective tissue viscosity that diverges at the liquid-solid transition. (pnas.org)
Thermo-mechanical stress3
  • The state of the art shows a substantial knowledge deficit about the influence of the volumetric grinding wheel composition and the resulting grinding wheel topography on the thermo-mechanical stress collective acting on the workpiece external zone. (mdpi.com)
  • Therefore, the aim of the current research is an empirical-analytical model for the prediction of the thermo-mechanical stress collective as a function of the grinding wheel topography. (mdpi.com)
  • The obtained results are summarized and are used to explain the thermo-mechanical stress collective as a function of the grinding wheel topography. (mdpi.com)
Tissues13
  • Here we show that the pattern of branching morphogenesis of three-dimensional (3D) engineered epithelial tissues is controlled in part by gradients of endogenous mechanical stress. (nih.gov)
  • Branches initiated from sites of high mechanical stress within the tissues, as predicted numerically and measured directly using 3D traction force microscopy. (nih.gov)
  • These data suggest that the pattern and magnitude of mechanical stress across epithelial tissues cooperate with biochemical signals to specify branching pattern. (nih.gov)
  • According to Prof. Gefen, applying mechanical loads on tissues can affect many different cells within our bodies. (medindia.net)
  • When we stress our body in our yoga practice, we obviously stress our tissues. (yinyoga.com)
  • Our tissues are made up of cell, so we also stress the cells. (yinyoga.com)
  • Cells and tissues can be protected against a potentially lethal stress by first exposing them to a brief dose of the same or different stress. (nih.gov)
  • Tissues develop their shape through mechanical processes. (biologists.org)
  • Mechanical stress, the internal distribution of forces within cells and tissues, is what make cells move, change shape, or exchange neighbors. (biologists.org)
  • How growth impacts on the distribution of stress and subsequent shaping of tissues is not known. (biologists.org)
  • Our work provides a unifying framework for existing, seemingly distinct notions of stress in tissues and relates stresses to material properties. (pnas.org)
  • Using a self-propelled Voronoi (SPV) model that links cell mechanics to cell shape and cell motility, we formulate a generalized mechanical inference method to obtain the spatiotemporal distribution of cellular stresses from measured traction forces in motile tissues and show that such traction-based stresses match those calculated from instantaneous cell shapes. (pnas.org)
  • To make quantitative predictions for large-scale cell remodeling in tissues, we must understand their material properties, such as stiffness and viscosity, as well as the forces that build up inside them, characterized by local pressures and stresses. (pnas.org)
Piping Design8
  • How Mechanical Piping Design can Save You Time, Stress, and Money. (affiliatblogger.com)
  • Mechanical Piping Design is Among the many most highly regarded engineering, challenge management, and building corporations on the globe. (affiliatblogger.com)
  • The detailer will not be typically responsible for design, which include structural strength and integrity (which Mechanical Piping Design happen to be the duty of the structural engineer), key dimensions with the structure and compliance with suitable developing codes (which happen to be the duty of your architect). (affiliatblogger.com)
  • We at Mechanical Piping Design possess the know-how to investigate the design of failed equipment factors to find out whether or not the failure could possibly be attributed to shortcomings in design or manufacture, or whether it was due to misuse, insufficient upkeep, content decision, or other components involving the consumers or the ecosystem where it absolutely was used. (full-design.com)
  • The engineers at Mechanical Piping Design can offer you designs and development solutions involving CAD and CAE, notion generations, design briefs, evaluation and documentation, prototype development website and screening and manufacturing assistance. (full-design.com)
  • In addition, MPD's staff have performed Vitality Mechanical Piping Design management and utilized Strength conservation procedures which includes computerized Power Evaluation, daily life cycle costing. (full-design.com)
  • Mechanical Piping Design is among the most highly regarded engineering, project administration, and design corporations in the world. (full-design.com)
  • Mechanical Piping Design is here, with lots of expertise and experience to serve you in all kinds of back end engineering activities. (bloguetechno.com)
Activates5
Finite element2
  • The local distribution of near-surface stress in Si has been measured, in comparison with stress analysis of the TSV structure based on a semi-analytic approach and finite element analysis. (utexas.edu)
  • Stress concentration factors have been calculated using finite element analysis (FEA). (diva-portal.org)
Local stresses1
Internal stresses2
  • The finite element models of lumbar motion segments were useful in analyzing internal stresses, given segment geometry, material properties and applied loads. (cdc.gov)
  • It was found that the major parameters that influence the generation of internal stresses were the exposure time, the post-baking temperature and time and the concentration of the photo-initiator used (Cyracure UVI). (nsti.org)
Exert3
Influence7
  • This is the first time that a mechanical constraint has been shown to influence the genetic control of the development of Drosophila embryo. (innovations-report.com)
  • This aim of the present narrative review was to illustrate the current evidence on the importance of mechanical stress in the pathophysiology of lung diseases with a particular focus on chronic obstructive pulmonary disease (COPD) and to discuss how this may influence pharmacological treatment strategies. (hindawi.com)
  • This narrative review describes the current evidence on the importance of mechanical stress in the pathophysiology of lung diseases and chronic obstructive pulmonary disease (COPD) and discusses how this can influence treatment selection. (hindawi.com)
  • Richardson, P., Davies, M. and Born, G. (1989) Influence of plaque configuration and stress distribution of coronary atherosclerotic plaques. (scirp.org)
  • This is the first handbook containing extensive information on the influence of the stress on the material properties. (begellhouse.com)
  • The influence of the stress mode on the crack growth resistance has been covered in detail. (begellhouse.com)
  • The influence of mechanical forces has undergone minimal investigation to date: multicellular organisms are subject to significantly greater stress than single-celled organisms. (idw-online.de)
Differentiation5
Relaxation2
  • We show that divisions orient with the long cell axis rather than with the stress direction, and show how oriented divisions contribute to the restoration of cell packing and stress relaxation. (pnas.org)
  • To do this, we used suspended monolayers devoid of ECM, where divisions become oriented following a stretch, allowing the regulation and function of epithelial division orientation in stress relaxation to be characterized. (pnas.org)
Elasticity2
  • For transverse motion, mechanical signal transmission is dominated by prestress while fiber elasticity has a negligible effect. (biomedsearch.com)
  • A.N. Parbhu, W.G. Bryson, and R. Lal, Disulļ¬de bonds in theouter layer of keratin ļ¬bres confer higher mechanical rigidity:Correlative nano-indentation and elasticity measurement withan AFM, Biochemistry, 38, 1999, 11755-11761. (actapress.com)
Metabolism3
Cells37
  • Cells probably use this ability to protect themselves from mechanical overstimulation, as reported in an article published in the journal Nature Communications initiated and carried out by Dr. Mirko Moroni, the lead author, and other members of Lewin's research group. (eurekalert.org)
  • The mechanism seems to protect blood cells from the mechanical stress they would otherwise be permanently exposed to as they travel through narrow blood vessels. (eurekalert.org)
  • Here we examine how two different cell types, one that undergoes the stress and the other that primarily remodels the matrix, might communicate a mechanical stress by using airway cells as a representative in vitro system. (mendeley.com)
  • When mechanical pressure is applied to the embryo, Ɵ catenin enters the cell nucleus (on right), whereas to perform its role as an "adhesive" between cells it must be on the cell surface. (innovations-report.com)
  • But on applying mechanical pressure to the Drosophila embryo, Emmanuel Farge noted that the Twist gene was then expressed in all the embryo's cells. (innovations-report.com)
  • Henceforth it will be necessary to take into account the mechanical sensitivity of living cells. (innovations-report.com)
  • How fat cells respond to mechanical loads can be studied now through a new method developed by researchers at the Tel Aviv University. (medindia.net)
  • By recreating the structure of fat cells using a newly-developed computer method, Prof. Gefen and his team of researchers can determine how much mechanical load can be tolerated by fat cells, and at what point the cells will begin to disintegrate. (medindia.net)
  • He believes that, much like bone or muscle cells, fat cells are also affected by mechanical loads. (medindia.net)
  • After assembling their "virtual" fat cells, Prof. Gefen and his group found that fat cells or lipids have a point where mechanical loads can disintegrate them, as well as a point at which they are able to resist disintegration. (medindia.net)
  • Cells are constantly adjusting to the mechanical properties of their surroundings, operating a complex mechanochemical feedback, which hinges on mechanotransduction mechanisms. (mdpi.com)
  • This study shows how that stress on the cells can affect gene expression: turning on or off certain genes depending upon the direction and intensity of the stress. (yinyoga.com)
  • The age-effect is reasonable, since younger cells, which are actively shaping their cell walls, are more vulnerable to altered mechanical stresses while in leaves older than 19 DAS, the walls are more robust and therefore can sustain the applied forces. (nih.gov)
  • This process may be triggered by several factors including inflammation, mechanical stress or interaction of cells with certain components of extracellular matrix. (frontiersin.org)
  • The cells were stressed by suspending them in laminar simple shear flows. (rice.edu)
  • Stress effects on tumor cells were studied using high and low metastatic sub-lines of the B16 melanoma and the RAW117 large cell lymphoma. (rice.edu)
  • The cells were stressed at 0, 450 and 900 dynes/cm$\sp2$ at 37$\sp\circ$C for 5 min. (rice.edu)
  • The results could by modeled assuming that a subpopulation of stressed cells was lethally damaged and ultimately died while a second group of stressed cells were only sublethally damaged and grew normally after a brief lag-time. (rice.edu)
  • Although the stresses applied were higher than normally seen in vivo, the results are in contrast to the accepted view that mechanical stresses developed in the circulation directly cause the destruction of most of the tumor cells during blood-borne metastasis and that highly metastatic cells can resist these stresses more effectively than poorly metastatic cells. (rice.edu)
  • The opposite situation is that of loosely connected cells, which can make way for growth, resulting in an effective fluid flow where no mechanical stress is generated, as in cultured multicellular spheroids. (biologists.org)
  • The purpose of the present study was to examine responses of trabecular meshwork (TM) cells to cyclic biomechanical stress in the presence and absence of compounds known to affect cell contractility. (arvojournals.org)
  • Although mechanical stress appeared to have no effect, Y27632 decreased phosphorylated myosin light chain, filamentous/globular actin ratio, and stress fiber formation in TM cells. (arvojournals.org)
  • Mechanical forces exerted on cells impose stress on the plasma membrane. (semanticscholar.org)
  • Cells sense this stress and elicit a mechanoelectric transduction cascade that initiates compensatory mechanisms. (semanticscholar.org)
  • Effects of transient receptor potential canonical 1 (TRPC1) on the mechanical stretch-induced expression of airway remodeling-associated factors in human bronchial epithelioid cells. (semanticscholar.org)
  • In isolated adherent cells, the orientation of mitotic spindles is sensitive to interphase cell shape and the direction of extrinsic mechanical forces. (pnas.org)
  • This article discusses the problem of the turbulent " shear " in biotechnology including the effect of the shear stress on particles (cells, flocs, cells immobilized on microcarriers). (asme.org)
  • Among the bone cells, osteocytes act as a major role in bone remodelling during orthodontic tooth movement against mechanical stress. (elsevier.com)
  • however, is not clear how these cells sense and transmit mechanical signals. (jci.org)
  • A research project by scientists at Kiel University (CAU), the University of MĆ¼nster (WWU) and Cornell University, USA, is investigating how cells have learned to adapt to mechanical stress to avoid damage during the course of evolution. (idw-online.de)
  • Mechanical pressure on cells also plays a role in illnesses: genetic mutations that alter the mechanical load-bearing capacity of cells can, for example, lead to muscle weakness (muscular dystrophy) and heart disease. (idw-online.de)
  • The fact that cells react to mechanical influences is nothing new in research. (idw-online.de)
  • At the interface between biology and engineering, mechanobiology investigates the mechanical properties of cells and the physical forces at work there. (idw-online.de)
  • In addition to the cellular adaptation strategies that have possibly emerged during the course of evolution, they are also interested in how the mechanical forces in single-celled and multicellular organisms differ and how they are transferred from the surface of the cells to their nucleus. (idw-online.de)
  • Class I, II, and IV members are known to be involved in hormone signaling, stress acclimation, and floral development, and are crucial for regulation of plant cells growth. (frontiersin.org)
  • Fluorescent labeling of cysteines in living cells reveals how mechanical stress can cause force-induced conformational changes in cellular proteins. (sciencemag.org)
  • Mechanical interactions among cells provide an important regulatory mechanism to coordinate such collective motion. (pnas.org)
Genes7
  • Emmanuel Farge, a researcher at the Institut Curie, lecturer at the Paris VII University, and member of the Institut Universitaire de France, has just shown that mechanical pressure applied to a fly embryo influences the expression of its developmental genes. (innovations-report.com)
  • b catenin could be the link between mechanical pressure and genes. (innovations-report.com)
  • Inflammation and mechanical stress trigger expression of osteogenic genes in VICs in a side-specific manner, while inhibiting the myofibroblastic pathway. (frontiersin.org)
  • The results showed that the stressed plants had stronger antifungal activities and were 'primed' for defense with enhanced expression levels of defense-related genes following fungal inoculation. (hawaii.edu)
  • This was preceded by a rapid change in calcium concentration and a release of ROS, accompanied by changes in cuticle permeability, induction of the expression of genes typically associated with mechanical stress and release of biologically active diffusates from the surface. (biomedcentral.com)
  • Whereas the growth of the cranial base cartilage is thought to be regulated solely by genes, epiphyseal growth plates are known to respond to mechanical stresses. (semanticscholar.org)
  • The cDNA microarray analysis revealed that, of 1080 genes, 37 genes were upregulated and 46 genes were downregulated after mechanical stress. (biomedcentral.com)
ANSYS Mechanical2
  • The new and improved Second Edition contains additional chapters on APDL Math and APDL in ANSYS Mechanical. (padtinc.com)
  • This post shows how Ansys Mechanical does it and offers an alternative that is considered more accurate for some cases. (padtinc.com)
Contractility2
  • Mechanical stress profiles of tubules with increasing contractility: prestress (p t ) that yields prestrain (Īµ 0 ) of (A) 0.2 % (B) 0.6 % (C) 1% and (D) combined stress profiles. (nih.gov)
  • We identify a motility-induced swim stress that adds to the interaction stress to determine the global contractility or extensibility of epithelia. (pnas.org)
Mechanisms3
  • However, the mechanisms underlying channel activation in response to mechanical stress remain incompletely understood. (semanticscholar.org)
  • Although the participation of GRPs in plant stress response has been indicated in numerous model and non-model plant species, relatively little is known about the key physiological processes and molecular mechanisms in which those proteins are engaged. (frontiersin.org)
  • To understand the complex mechanisms affecting plant growth and development under stress-inducing conditions, a number of studies on economically and ecologically important species are currently underway. (frontiersin.org)
Elastic3
  • More interestingly, we succeeded in the demonstration of novel mechanical stress sensing by the elastic CLC films of crosslinked HPC derivatives, leading to the visualization of external mechanical stress as the changes in Bragg reflection color. (or.jp)
  • Using a physical model, we demonstrate that stress fibres behave elastic-like, even at timescales exceeding turnover of constituent proteins. (nature.com)
  • In liquids and gases, only deformations that change the volume generate persistent elastic stress. (wikipedia.org)
Vivo4
Endure3
  • In all this, bone must be as lightweight as possible to decrease the overall body mass yet have the mechanical ability to endure stresses whenever a force is loaded upon them. (scirp.org)
  • however, most modern portable electronic products used in automobiles, personal digital assistants (PDA), and aircraft have to endure extreme environments that involve not only thermal but also mechanical loading conditions. (smta.org)
  • To endure all these stresses, crystalline arrays of cellulose microfibrils are deposited into the wall. (biomedcentral.com)
Measurement1
  • Second, the limitation of conventional Raman measurement is discussed, and two different kinds of innovative Raman measurements have been developed and employed to study the normal stress components separately by taking advantages of different laser polarization configuration. (utexas.edu)
Temperature3
  • Nevertheless, the permeability changes observed during these tests seem to be directly connected to the nature and structure of the material sustains under changes of temperature and stress. (lyellcollection.org)
  • Direct the use of CAEPIPE piping system stress analysis software to determine weight, pressure, temperature, & earthquake. (indeed.com)
  • Direct the use of appropriate piping system stress analysis software (Autopipe, Caesar or similar)to determine weight, pressure, temperature, & earthquake. (indeed.com)
Detrimental1
Arabidopsis4
  • Mechanical stress in Arabidopsis leaves orients microtubules in a 'continuous' supracellular pattern. (nih.gov)
  • Confocal microscopy examination of transgenic plants bearing GFP-tagged TUA6 proteins led to the observation that application of an additional mechanical pressure on growing Arabidopsis leaves triggers an excessive bundling of microtubules within the individual cell. (nih.gov)
  • The capacity of the imposition of a mechanical stress (periodic brushing) to reduce the height of the inflorescence stem of Arabidopsis thaliana seedlings has been used to study the role of pectic arabinans in the mechanical properties and stress responsiveness of a plant organ. (whiterose.ac.uk)
  • Arabidopsis can detect and convert gentle forms of mechanical stimulation into a strong activation of defense against the virulent fungus B. cinerea . (biomedcentral.com)
Engineers6
Turbulent1
Embryos3
Triggers2
Significantly6
Epithelial1
Adaptation1
  • The object of this study is to provide evidence for new ways to explore bone's functional adaptation to mechanical stress made through the copious interpretation and integration of new and existing literature. (scirp.org)
Responses6
Turbine2
Cytoskeleton1
  • Here, we review recent advances demonstrating that mechanical stress emanating from the cytoskeleton can activate pathways in the nucleus which eventually impact both its structure and the transcriptional machinery. (mdpi.com)
Mediates1
  • The present results suggest that cytoskeletal prestress mediates rapid mechanical signal transmission and allows temporally oscillatory signals in the physiological frequency range to travel a long distance without significant decay due to material viscosity and/or cytosolic drag. (biomedsearch.com)
Rats3
  • Administration of stress levels of epinephrine to adrenal medullectomized rats reconstituted the pain phenotype. (pubmedcentralcanada.ca)
  • Based on our studies using a model of intermittent sound stress in rats, we have suggested that sound stress-induced enhancement of immune mediator hyperalgesia requires activity in both neuroendocrine stress axes: the sympathoadrenal (via release of epinephrine) and hypothalamic pituitary adrenal (HPA) (via release of corticosterone) 12 . (pubmedcentralcanada.ca)
  • Stress-induced long-lasting changes in the catecholamine-synthesizing enzymes may contribute to this prolonged elevation of plasma epinephrine levels in sound stressed rats 12 . (pubmedcentralcanada.ca)
Less mechanical stress4
Signaling1
Mechanical Stress Downregulates MHC Class I Expression on Human Cancer Cell Membrane
Mechanical Stress Downregulates MHC Class I Expression on Human Cancer Cell Membrane (journals.plos.org)
Rock | Definition, Characteristics, & Types | Britannica.com
Rock | Definition, Characteristics, & Types | Britannica.com (britannica.com)
An Implantable Micro-Caged Device for Direct Local Delivery of Agents | Scientific Reports
An Implantable Micro-Caged Device for Direct Local Delivery of Agents | Scientific Reports (nature.com)
Mechanical stress modulates bone remodeling signals | SpringerLink
Mechanical stress modulates bone remodeling signals | SpringerLink (link.springer.com)
How cells protect themselves against mechanical stress | EurekAlert! Science News
How cells protect themselves against mechanical stress | EurekAlert! Science News (eurekalert.org)
JCI - Welcome
JCI - Welcome (jci.org)
Table of Contents - August 07, 2007, 2007 (398) | Science Signaling
Table of Contents - August 07, 2007, 2007 (398) | Science Signaling (stke.sciencemag.org)
A close relationship: the brain and its blood vessels | Max-Planck-Gesellschaft
A close relationship: the brain and its blood vessels | Max-Planck-Gesellschaft (mpg.de)
NIOSHTIC-2 Publications Search - 00181265 - Back injuries: mechanical stresses in the human spine.
NIOSHTIC-2 Publications Search - 00181265 - Back injuries: mechanical stresses in the human spine. (cdc.gov)
Solder Alloy Creep Constants for Use in Thermal Stress Analysis - Journal of SMT
Solder Alloy Creep Constants for Use in Thermal Stress Analysis - Journal of SMT (smta.org)
Max Adaptation Upper Lower (MAUL) Workout
Max Adaptation Upper Lower (MAUL) Workout (muscleandstrength.com)
ED Pigments
ED Pigments (clariant.com)
Increasing carbon dioxide relieves drought stress in corn
Increasing carbon dioxide relieves drought stress in corn (innovations-report.com)
Fat Cells and Their Response to Mechanical Stress
Fat Cells and Their Response to Mechanical Stress (medindia.net)
Naked Ride organizers stress over costs (let's help them out!) - BikePortland.org
Naked Ride organizers stress over costs (let's help them out!) - BikePortland.org (bikeportland.org)
NIOSHTIC-2 Publications Search - 00057377 - Nonlinear behavior of the human intervertebral disc under axial load.
NIOSHTIC-2 Publications Search - 00057377 - Nonlinear behavior of the human intervertebral disc under axial load. (cdc.gov)
Control of Health and Safety Hazards in Commercial Dry Cleaners | NIOSH | CDC
Control of Health and Safety Hazards in Commercial Dry Cleaners | NIOSH | CDC (cdc.gov)
Engineering - Mechanical Jobs in Crystal City, VA - ClearanceJobs
Engineering - Mechanical Jobs in Crystal City, VA - ClearanceJobs (clearancejobs.com)
Stress Analysis of Multilayered Printed Circuit Board under Mechanical Loading - Journal of SMT
Stress Analysis of Multilayered Printed Circuit Board under Mechanical Loading - Journal of SMT (smta.org)
Electrothermal mechanical stress reference design flow for printed circuit boards - The Engineer The Engineer
Electrothermal mechanical stress reference design flow for printed circuit boards - The Engineer The Engineer (theengineer.co.uk)
2018 | Max Planck Institute of Biochemistry
2018 | Max Planck Institute of Biochemistry (biochem.mpg.de)
Timber Designers' Manual, 3rd Edition | Timber Construction | General & Introductory Civil Engineering & Construction |...
Timber Designers' Manual, 3rd Edition | Timber Construction | General & Introductory Civil Engineering & Construction |... (wiley.com)
Kombucha | Memorial Sloan Kettering Cancer Center
Kombucha | Memorial Sloan Kettering Cancer Center (mskcc.org)
Mechanical Link: Fundamental Principles, Theory, and Practice Following an ... - Paul Chauffour, Eric Prat - Google Books
Mechanical Link: Fundamental Principles, Theory, and Practice Following an ... - Paul Chauffour, Eric Prat - Google Books (books.google.com)
Soft Matter News - Soft matter, Soft condensed matter, Physics News
Soft Matter News - Soft matter, Soft condensed matter, Physics News (phys.org)
September-October 1997 - Volume 43 - Issue 5 : ASAIO Journal
September-October 1997 - Volume 43 - Issue 5 : ASAIO Journal (journals.lww.com)
Transfusion Related Acute Lung Injury - 899 Words | Bartleby
Transfusion Related Acute Lung Injury - 899 Words | Bartleby (bartleby.com)
Vibration of Continuous Systems | Mechanical Engineering - Design | General & Introductory Mechanical Engineering | Subjects |...
Vibration of Continuous Systems | Mechanical Engineering - Design | General & Introductory Mechanical Engineering | Subjects |... (wiley.com)
Journal of Applied Mechanics | ASME - ASME
Journal of Applied Mechanics | ASME - ASME (asme.org)
Crystal | physics | Britannica.com
Crystal | physics | Britannica.com (britannica.com)
Foundations for Guided-Wave Optics / Edition 1 by Chin-Lin Chen | 9780471756873 | Hardcover | Barnes & NobleĀ®
Foundations for Guided-Wave Optics / Edition 1 by Chin-Lin Chen | 9780471756873 | Hardcover | Barnes & NobleĀ® (barnesandnoble.com)