Condition of having pores or open spaces. This often refers to bones, bone implants, or bone cements, but can refer to the porous state of any solid substance.
A circular structural unit of bone tissue. It consists of a central hole, the Haversian canal through which blood vessels run, surrounded by concentric rings, called lamellae.
The testing of materials and devices, especially those used for PROSTHESES AND IMPLANTS; SUTURES; TISSUE ADHESIVES; etc., for hardness, strength, durability, safety, efficacy, and biocompatibility.
The maximum compression a material can withstand without failure. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed, p427)
Cell growth support structures composed of BIOCOMPATIBLE MATERIALS. They are specially designed solid support matrices for cell attachment in TISSUE ENGINEERING and GUIDED TISSUE REGENERATION uses.
Microscopy in which the object is examined directly by an electron beam scanning the specimen point-by-point. The image is constructed by detecting the products of specimen interactions that are projected above the plane of the sample, such as backscattered electrons. Although SCANNING TRANSMISSION ELECTRON MICROSCOPY also scans the specimen point by point with the electron beam, the image is constructed by detecting the electrons, or their interaction products that are transmitted through the sample plane, so that is a form of TRANSMISSION ELECTRON MICROSCOPY.
Polymers of organic acids and alcohols, with ester linkages--usually polyethylene terephthalate; can be cured into hard plastic, films or tapes, or fibers which can be woven into fabrics, meshes or velours.
Generating tissue in vitro for clinical applications, such as replacing wounded tissues or impaired organs. The use of TISSUE SCAFFOLDING enables the generation of complex multi-layered tissues and tissue structures.
Synthetic or natural materials, other than DRUGS, that are used to replace or repair any body TISSUES or bodily function.
Material from which the casting mold is made in the fabrication of gold or cobalt-chromium castings. (Boucher's Clinical Dental Terminology, 4th ed, p168)
Production of a radiographic image of a small or very thin object on fine-grained photographic film under conditions which permit subsequent microscopic examination or enlargement of the radiograph at linear magnifications of up to several hundred and with a resolution approaching the resolving power of the photographic emulsion (about 1000 lines per millimeter).
Synthetic or natural materials for the replacement of bones or bone tissue. They include hard tissue replacement polymers, natural coral, hydroxyapatite, beta-tricalcium phosphate, and various other biomaterials. The bone substitutes as inert materials can be incorporated into surrounding tissue or gradually replaced by original tissue.
Substances made up of an aggregation of small particles, as that obtained by grinding or trituration of a solid drug. In pharmacy it is a form in which substances are administered. (From Dorland, 28th ed)
Characteristics or attributes of the outer boundaries of objects, including molecules.
X-RAY COMPUTERIZED TOMOGRAPHY with resolution in the micrometer range.
A biocompatible polymer used as a surgical suture material.
Artificial substitutes for body parts and materials inserted into organisms during experimental studies.
The species Balaena mysticetus, in the family Balaenidae, found in the colder waters of the Northern Hemisphere. The common name is derived from the extreme arching of the lower jaw.
Calcium salts of phosphoric acid. These compounds are frequently used as calcium supplements.
The longest and largest bone of the skeleton, it is situated between the hip and the knee.
The mineral component of bones and teeth; it has been used therapeutically as a prosthetic aid and in the prevention and treatment of osteoporosis.
A specialized CONNECTIVE TISSUE that is the main constituent of the SKELETON. The principle cellular component of bone is comprised of OSTEOBLASTS; OSTEOCYTES; and OSTEOCLASTS, while FIBRILLAR COLLAGENS and hydroxyapatite crystals form the BONE MATRIX.
Solid dosage forms, of varying weight, size, and shape, which may be molded or compressed, and which contain a medicinal substance in pure or diluted form. (Dorland, 28th ed)
Compounds formed by the joining of smaller, usually repeating, units linked by covalent bonds. These compounds often form large macromolecules (e.g., BIOPOLYMERS; PLASTICS).
The mechanical property of material that determines its resistance to force. HARDNESS TESTS measure this property.
Adhesives used to fix prosthetic devices to bones and to cement bone to bone in difficult fractures. Synthetic resins are commonly used as cements. A mixture of monocalcium phosphate, monohydrate, alpha-tricalcium phosphate, and calcium carbonate with a sodium phosphate solution is also a useful bone paste.
Products made by baking or firing nonmetallic minerals (clay and similar materials). In making dental restorations or parts of restorations the material is fused porcelain. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed & Boucher's Clinical Dental Terminology, 4th ed)
A group of thermoplastic or thermosetting polymers containing polyisocyanate. They are used as ELASTOMERS, as coatings, as fibers and as foams.
Relating to the size of solids.
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.
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.
The continuous turnover of BONE MATRIX and mineral that involves first an increase in BONE RESORPTION (osteoclastic activity) and later, reactive BONE FORMATION (osteoblastic activity). The process of bone remodeling takes place in the adult skeleton at discrete foci. The process ensures the mechanical integrity of the skeleton throughout life and plays an important role in calcium HOMEOSTASIS. An imbalance in the regulation of bone remodeling's two contrasting events, bone resorption and bone formation, results in many of the metabolic bone diseases, such as OSTEOPOROSIS.
A plant genus of the family OLEACEAE. Members contain secoiridoid glucosides.
Nanometer-scale composite structures composed of organic molecules intimately incorporated with inorganic molecules. (Glossary of Biotechnology and Nanobiotechology Terms, 4th ed)
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)
A group of phosphate minerals that includes ten mineral species and has the general formula X5(YO4)3Z, where X is usually calcium or lead, Y is phosphorus or arsenic, and Z is chlorine, fluorine, or OH-. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
Submicron-sized fibers with diameters typically between 50 and 500 nanometers. The very small dimension of these fibers can generate a high surface area to volume ratio, which makes them potential candidates for various biomedical and other applications.
Renewal or repair of lost bone tissue. It excludes BONY CALLUS formed after BONE FRACTURES but not yet replaced by hard bone.
Physical reactions involved in the formation of or changes in the structure of atoms and molecules and their interactions.
The shaft of long bones.
Property of membranes and other structures to permit passage of light, heat, gases, liquids, metabolites, and mineral ions.
The family of carnivorous or omnivorous bears, having massive bodies, coarse heavy fur, relatively short limbs, and almost rudimentary tails.
The preparation, mixing, and assembling of a drug. (From Remington, The Science and Practice of Pharmacy, 19th ed, p1814)
A polymer prepared from polyvinyl acetates by replacement of the acetate groups with hydroxyl groups. It is used as a pharmaceutic aid and ophthalmic lubricant as well as in the manufacture of surface coatings artificial sponges, cosmetics, and other products.
Deacetylated CHITIN, a linear polysaccharide of deacetylated beta-1,4-D-glucosamine. It is used in HYDROGEL and to treat WOUNDS.
The properties, processes, and behavior of biological systems under the action of mechanical forces.
The evaluation of incidents involving the loss of function of a device. These evaluations are used for a variety of purposes such as to determine the failure rates, the causes of failures, costs of failures, and the reliability and maintainability of devices.
The outer shorter of the two bones of the FOREARM, lying parallel to the ULNA and partially revolving around it.
Materials which have structured components with at least one dimension in the range of 1 to 100 nanometers. These include NANOCOMPOSITES; NANOPARTICLES; NANOTUBES; and NANOWIRES.
Process by which unwanted microbial, plant or animal materials or organisms accumulate on man-made surfaces.
A clear, odorless, tasteless liquid that is essential for most animal and plant life and is an excellent solvent for many substances. The chemical formula is hydrogen oxide (H2O). (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
A plant genus of the family FABACEAE.
The second longest bone of the skeleton. It is located on the medial side of the lower leg, articulating with the FIBULA laterally, the TALUS distally, and the FEMUR proximally.
Water swollen, rigid, 3-dimensional network of cross-linked, hydrophilic macromolecules, 20-95% water. They are used in paints, printing inks, foodstuffs, pharmaceuticals, and cosmetics. (Grant & Hackh's Chemical Dictionary, 5th ed)
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.
A dark-gray, metallic element of widespread distribution but occurring in small amounts; atomic number, 22; atomic weight, 47.90; symbol, Ti; specific gravity, 4.5; used for fixation of fractures. (Dorland, 28th ed)
Chemistry dealing with the composition and preparation of agents having PHARMACOLOGIC ACTIONS or diagnostic use.
Quartz (SiO2). A glassy or crystalline form of silicon dioxide. Many colored varieties are semiprecious stones. (From Grant & Hackh's Chemical Dictionary, 5th ed)
The use of computers for designing and/or manufacturing of anything, including drugs, surgical procedures, orthotics, and prosthetics.
The amount of mineral per square centimeter of BONE. This is the definition used in clinical practice. Actual bone density would be expressed in grams per milliliter. It is most frequently measured by X-RAY ABSORPTIOMETRY or TOMOGRAPHY, X RAY COMPUTED. Bone density is an important predictor for OSTEOPOROSIS.
The joining of objects by means of a cement (e.g., in fracture fixation, such as in hip arthroplasty for joining of the acetabular component to the femoral component). In dentistry, it is used for the process of attaching parts of a tooth or restorative material to a natural tooth or for the attaching of orthodontic bands to teeth by means of an adhesive.
A cellulose derivative which is a beta-(1,4)-D-glucopyranose polymer. It is used as a bulk laxative and as an emulsifier and thickener in cosmetics and pharmaceuticals and as a stabilizer for reagents.
Mature osteoblasts that have become embedded in the BONE MATRIX. They occupy a small cavity, called lacuna, in the matrix and are connected to adjacent osteocytes via protoplasmic projections called canaliculi.
A generic grouping for dihydric alcohols with the hydroxy groups (-OH) located on different carbon atoms. They are viscous liquids with high boiling points for their molecular weights.
Salts and esters of the 10-carbon monocarboxylic acid-decanoic acid.
The growth action of bone tissue as it assimilates surgically implanted devices or prostheses to be used as either replacement parts (e.g., hip) or as anchors (e.g., endosseous dental implants).
Magnesium oxide (MgO). An inorganic compound that occurs in nature as the mineral periclase. In aqueous media combines quickly with water to form magnesium hydroxide. It is used as an antacid and mild laxative and has many nonmedicinal uses.
A process of separating particulate matter from a fluid, such as air or a liquid, by passing the fluid carrier through a medium that will not pass the particulates. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
The buckthorn plant family, of the order Rhamnales, includes some species with edible fruits and some that are medicinal.
A normal intermediate in the fermentation (oxidation, metabolism) of sugar. The concentrated form is used internally to prevent gastrointestinal fermentation. (From Stedman, 26th ed)
Small uniformly-sized spherical particles, of micrometer dimensions, frequently labeled with radioisotopes or various reagents acting as tags or markers.
Method of tissue preparation in which the tissue specimen is frozen and then dehydrated at low temperature in a high vacuum. This method is also used for dehydrating pharmaceutical and food products.
Polyester polymers formed from terephthalic acid or its esters and ethylene glycol. They can be formed into tapes, films or pulled into fibers that are pressed into meshes or woven into fabrics.
The process of bone formation. Histogenesis of bone including ossification.
A plant family of the order Violales, subclass Dilleniidae, class Magnoliopsida. Bixa contains bixin. Cochlospermum contains arjunolic acid and gum kondagogu (POLYSACCHARIDES).
The quality or state of being wettable or the degree to which something can be wet. This is also the ability of any solid surface to be wetted when in contact with a liquid whose surface tension is reduced so that the liquid spreads over the surface of the solid.
A polyester used for absorbable sutures & surgical mesh, especially in ophthalmic surgery. 2-Hydroxy-propanoic acid polymer with polymerized hydroxyacetic acid, which forms 3,6-dimethyl-1,4-dioxane-dione polymer with 1,4-dioxane-2,5-dione copolymer of molecular weight about 80,000 daltons.
Usually inert substances added to a prescription in order to provide suitable consistency to the dosage form. These include binders, matrix, base or diluent in pills, tablets, creams, salves, etc.
The process of producing a form or impression made of metal or plaster using a mold.
A network of cross-linked hydrophilic macromolecules used in biomedical applications.
Tantalum. A rare metallic element, atomic number 73, atomic weight 180.948, symbol Ta. It is a noncorrosive and malleable metal that has been used for plates or disks to replace cranial defects, for wire sutures, and for making prosthetic devices. (Dorland, 28th ed)
A space in which the pressure is far below atmospheric pressure so that the remaining gases do not affect processes being carried on in the space.
Resistance and recovery from distortion of shape.
The application of scientific knowledge or technology to pharmacy and the pharmaceutical industry. It includes methods, techniques, and instrumentation in the manufacture, preparation, compounding, dispensing, packaging, and storing of drugs and other preparations used in diagnostic and determinative procedures, and in the treatment of patients.
The dormant state in which some warm-blooded animal species pass the winter. It is characterized by narcosis and by sharp reduction in body temperature and metabolic activity and by a depression of vital signs.
Computer-assisted study of methods for obtaining useful quantitative solutions to problems that have been expressed mathematically.
Polymerized methyl methacrylate monomers which are used as sheets, moulding, extrusion powders, surface coating resins, emulsion polymers, fibers, inks, and films (From International Labor Organization, 1983). This material is also used in tooth implants, bone cements, and hard corneal contact lenses.
Implants constructed of materials designed to be absorbed by the body without producing an immune response. They are usually composed of plastics and are frequently used in orthopedics and orthodontics.
The largest of three bones that make up each half of the pelvic girdle.
Process by which organic tissue becomes hardened by the physiologic deposit of calcium salts.
A trace element that constitutes about 27.6% of the earth's crust in the form of SILICON DIOXIDE. It does not occur free in nature. Silicon has the atomic symbol Si, atomic number 14, and atomic weight [28.084; 28.086].
Hard, amorphous, brittle, inorganic, usually transparent, polymerous silicate of basic oxides, usually potassium or sodium. It is used in the form of hard sheets, vessels, tubing, fibers, ceramics, beads, etc.
Procedures for enhancing and directing tissue repair and renewal processes, such as BONE REGENERATION; NERVE REGENERATION; etc. They involve surgically implanting growth conducive tracks or conduits (TISSUE SCAFFOLDING) at the damaged site to stimulate and control the location of cell repopulation. The tracks or conduits are made from synthetic and/or natural materials and may include support cells and induction factors for CELL GROWTH PROCESSES; or CELL MIGRATION.
Dosage forms of a drug that act over a period of time by controlled-release processes or technology.
A polyvinyl polymer of variable molecular weight; used as suspending and dispersing agent and vehicle for pharmaceuticals; also used as blood volume expander.
A product formed from skin, white connective tissue, or bone COLLAGEN. It is used as a protein food adjuvant, plasma substitute, hemostatic, suspending agent in pharmaceutical preparations, and in the manufacturing of capsules and suppositories.
Tablets coated with material that delays release of the medication until after they leave the stomach. (Dorland, 28th ed)

Coating titanium implants with bioglass and with hydroxyapatite. A comparative study in sheep. (1/1668)

This study compares the osteointegration of titanium implants coated with bioglass (Biovetro GSB formula) and with hydroxyapatite (HAP). Twenty-four bioglass-coated and 24 HAP-coated cylinders were implanted in the femoral diaphyses of sheep, and examined after 2, 4, 6, 8, 12, and 16 weeks. The HAP coating gave a stronger and earlier fixation to the bone than did bioglass. Bioglass formed a tissue interface which showed a macrophage reaction with little new bone formation activity. In contrast, HPA, showed intense new bone formation, with highly mineralised osseous trabeculae in the neighbourhood of the interface.  (+info)

Enthacrynic and acid effects on inner wall pores in living monkeys. (2/1668)

PURPOSE: The influence of the inner wall of Schlemm's canal on aqueous outflow facility remains poorly understood. We examined the relationship between inner wall pore characteristics and outflow facility in living primate eyes in which facility had been pharmacologically increased by ethacrynic acid (ECA) infusion and in contralateral control eyes. METHODS: Outflow facility (two-level constant pressure perfusion) was measured in eight pairs of living monkey eyes before and after administration of a bolus dose of either 0.125 mM ECA or vehicle. After exsanguination, eyes were fixed in situ under constant-pressure conditions (mean fixation pressure approximately 19 mm Hg). The density and diameter of inner wall pores and the number and area of platelet aggregates on the inner wall of Schlemm's canal were measured by scanning electron microscopy. RESULTS: In ECA-treated eyes, outflow facility increased 63% (P < 0.0001), intracellular pore density decreased 46% (P = 0.0094), intracellular pore size increased 27% (P = 0.049), platelet aggregate density increased 158% (P < 0.0001), and area covered by platelets increased 210% (P = 0.012) relative to contralateral controls. Although the average density and size of intercellular pores were essentially unaffected by ECA, an increased density of large (> or = 1.90 microm) intercellular pores was seen in ECA-treated eyes. The density of intracellular pores increased with the duration of fixative perfusion. Other than a weak negative correlation between outflow facility and intracellular pore density in ECA-treated eyes (P = 0.052), facility was not correlated with inner wall pore features. CONCLUSIONS: Our data are most consistent with a scenario in which ECA promotes formation of large intercellular pores in the inner wall of Schlemm's canal, which are then masked by platelet aggregates. Masking of intercellular pores, combined with fixation-induced alteration of inner wall pore density, greatly complicates attempts to relate facility to inner wall structure and suggests that in vivo pore density is smaller than in fixed tissue. Additionally, facility-influencing effects of ECA on the juxtacanalicular tissue cannot be excluded.  (+info)

Effects of ethacrynic acid on Schlemm's canal inner wall and outflow facility in human eyes. (3/1668)

PURPOSE: The role of the inner wall of Schlemm's canal in determining aqueous outflow facility is poorly understood. To quantify the relationship between inner wall pore characteristics and aqueous outflow facility in human eyes, both control eyes and eyes in which facility had been pharmacologically increased by ethacrynic acid (ECA) infusion were studied. METHODS: Outflow facility was measured in enucleated human eyes before and after delivery of 0.25 mM ECA (one eye of each of 6 pairs) or 2.5 mM ECA (one eye of each of 13 pairs). ECA, and vehicle in contralateral eyes, was delivered into Schlemm's canal by retroperfusion, thereby largely avoiding drug exposure to the trabecular meshwork. After facility measurement, eyes were fixed under conditions of either constant pressure (physiological intraocular pressure, 13 pairs) or "equal flow" (6 pairs) and were microdissected to expose the inner wall of Schlemm's canal. The density and diameter of intercellular and intracellular inner wall pores were measured using scanning electron microscopy. RESULTS: Retroperfusion with 2.5 mM ECA increased facility by 73% (P < 0.001), whereas 0.25 mM ECA increased facility by 19% (not statistically significant). The density of intercellular pores in the inner wall of Schlemm's canal was increased by 520% in 2.5 mM ECA-retroperfused eyes (P < 0.00004), whereas intracellular pore density remained approximately constant. Large pores (size > or = 1.1 microm) were particularly enhanced in ECA retroperfused eyes. The net change in facility due to ECA was not correlated with changes in pore density or other inner wall pore statistics. CONCLUSIONS: Our data are most consistent with a model in which pores in the inner wall of Schlemm's canal indirectly influence facility. However, measured changes in facility due to changes in inner wall properties did not agree with quantitative predictions of the pore funneling theory, suggesting that changes in facility may instead be due to gel leakage from the extracellular spaces of the juxtacanalicular tissue. More definitive experiments are required to confirm this hypothesis.  (+info)

Diffusion of macromolecules in agarose gels: comparison of linear and globular configurations. (4/1668)

The diffusion coefficients (D) of different types of macromolecules (proteins, dextrans, polymer beads, and DNA) were measured by fluorescence recovery after photobleaching (FRAP) both in solution and in 2% agarose gels to compare transport properties of these macromolecules. Diffusion measurements were conducted with concentrations low enough to avoid macromolecular interactions. For gel measurements, diffusion data were fitted according to different theories: polymer chains and spherical macromolecules were analyzed separately. As chain length increases, diffusion coefficients of DNA show a clear shift from a Rouse-like behavior (DG congruent with N0-0.5) to a reptational behavior (DG congruent with N0-2.0). The pore size, a, of a 2% agarose gel cast in a 0.1 M PBS solution was estimated. Diffusion coefficients of the proteins and the polymer beads were analyzed with the Ogston model and the effective medium model permitting the estimation of an agarose gel fiber radius and hydraulic permeability of the gels. Not only did flexible macromolecules exhibit greater mobility in the gel than did comparable-size rigid spherical particles, they also proved to be a more useful probe of available space between fibers.  (+info)

Molecular mechanism for pore-formation in lipid membranes by the hemolytic lectin CEL-III from marine invertebrate Cucumaria echinata. (5/1668)

The pore-forming activity of CEL-III, a Gal/GalNAc specific lectin from the Holothuroidea Cucumaria echinata, was examined using artificial lipid membranes as a model system of erythrocyte membrane. The carboxyfluorescein (CF)-leakage studies clearly indicated that CEL-III induced the formation of pores in the dipalmitoyl phosphatidyl choline (DPPC)-lactosyl ceramide (LacCer) liposomes effectively but not in the DPPC-glucosyl ceramide (GlcCer) liposomes or DPPC liposomes. Such a leakage of CF was strongly inhibited by lactose, a potent inhibitor of CEL-III, suggesting that the leakage is mediated through the specific binding of CEL-III to the carbohydrate chains on the surface of the liposomes. The leakage of CF from the DPPC-lactosyl ceramide liposomes was pH-dependent, and it increased with increasing pH. The immunoblotting analysis and circular dichroism data indicated that upon interaction with liposomes, CEL-III associated to form an oligomer concomitantly with a marked conformational change. Furthermore, channel measurements showed that CEL-III has an ability to form small ion channels in the planar lipid bilayers consisting of diphytanoylphosphatidylcholine and human globoside (Gb4Cer)/LacCer.  (+info)

Heat stress and protective clothing: an emerging approach from the United States. (6/1668)

There is little doubt that heat stress affects many workers adversely and that protective clothing generally adds to the burden. The ACGIH threshold limit value for heat stress is the guiding document for evaluation of heat stress in the United States. Adjustment factors have been used to reflect the change in heat stress imposed by different clothing ensembles. While the first proposed factors started with limited experimental data and professional judgment, heat balance methods in the laboratory have yielded better estimates of adjustment factors and for a wider selection of ensembles. These same experiments have provided the starting point to accounting for nonporous clothing in heat balance evaluation schemes such as required sweat rate. Proposed changes to the ACGIH TLV have been mentioned and a framework for thinking about controls presented.  (+info)

Field testing of a personal size-selective bioaerosol sampler. (7/1668)

Existing samplers for the collection of bioaerosols have been designed with the aim of maintaining biological stability of the collected material, and in general do not select particles in accordance with international conventions for aerosol sampling. Many have uncharacterised sampling efficiencies and few are designed as personal samplers. If standard personal dust samplers are used for bioaerosols the viability of collected microorganisms may be compromised by dehydration. The objective of this study was to evaluate a novel personal bioaerosol sampler designed to collect the inhalable dust fraction and further subdivide the sample into thoracic and respirable fractions. The new sampler was tested to see whether it enhanced the survival of the collected microorganisms, and was assessed for ease of use in the field and in subsequent laboratory analyses. A number of occupation-related field sites were selected where large concentrations of bioaerosols were to be expected. The prototype sampler was found to be simple to use. Analysis could be carried out with similar efficiency either with all three fractions together for a total count, or separately for size selective data. The sampler performed at least as well as the standard IOM filter method but with the added advantage of size fractionation. The field trials showed that for sampling periods lasting several hours, microorganism survival within the sampler was adequate for culture and identification of the organisms present. This new sampler is now commercially available. In addition to bioaerosol sampling, the principle of size selective sampling using porous foams can be applied to other occupational hygiene problems, and also to indoor air monitoring of PM10 and PM2.5 concentrations.  (+info)

Molecular dynamics of synthetic leucine-serine ion channels in a phospholipid membrane. (8/1668)

Molecular dynamics calculations were carried out on models of two synthetic leucine-serine ion channels: a tetrameric bundle with sequence (LSLLLSL)(3)NH(2) and a hexameric bundle with sequence (LSSLLSL)(3)NH(2). Each protein bundle is inserted in a palmitoyloleoylphosphatidylcholine bilayer membrane and solvated by simple point charge water molecules inside the pore and at both mouths. Both systems appear to be stable in the absence of an electric field during the 4 ns of molecular dynamics simulation. The water motion in the narrow pore of the four-helix bundle is highly restricted and may provide suitable conditions for proton transfer via a water wire mechanism. In the wider hexameric pore, the water diffuses much more slowly than in bulk but is still mobile. This, along with the dimensions of the pore, supports the observation that this peptide is selective for monovalent cations. Reasonable agreement of predicted conductances with experimentally determined values lends support to the validity of the simulations.  (+info)

The mechanical properties of the internal solid structure and the acoustic-mechanical interaction with a fluid determine the behaviour of porous materials when exposed to sound and vibration. Porous materials include foams, fibre materials and woven/unwoven fabrics, and have multiple applications in sound and vibration control. An elastic frame can provide them with mechanical stability when exposed to vibration. In this project you will acquire in-depth understanding of the vibroacoustic behaviour of porous materials used in hearing aids (HAs). You will explore alternative designs, materials, and fabrication techniques that can enhance their performance. You will benefit from the knowledge and tools available at CAMM to push the boundaries of this innovative research field. ...
Last week, I put up a post about good moisturizers for low porosity hair. This time, I want to talk about high porosity hair (you didnt think I would leave this out did you?). If you dont know how to test the difference, read this post. Unlike low porosity hair, high porosity hair absorbs moisture really well. However, it also loses moisture easily. Because the hair cuticles are often open, its hard for high porous hair to retain moisture. High porous hair can be attributed to heat damage, poor hair maintenance, harsh hair dyes or just good ole genes. Its usually thin and can break easily if not properly maintained. High porosity hair needs heavier products and sealants to aid in retaining moisture. Products that contain butters and thicker oils like shea butter, mango butter, babassu oil, olive oil and avocado oil can help to retain moisture high porosity hair. Also, protein-rich products aid in strengthen the hair. Proteins temporarily fill the porous gaps leaving the hair stronger and ...
A catalyst and a method of preparation of said catalyst is described herein. The catalyst includes one or more metals from Columns 6-10 of the Periodic Table and/or one or more compounds of one or more metals from Columns 6-10 of the Periodic Table, a pore size distribution with a median pore diameter ranging from 105 Å to 150 Å, with 60% of the total number of pores in the pore size distribution having a pore diameter within 60 Å of the median pore diameter, with at least 50% of its pore volume in pores having a pore diameter of at most 600 Å, and between 5% and 25% of its pore volume in pores having a pore diameter between 1000 Å and 5000 Å. Methods of producing said catalyst are described herein. Crude products and products made from said crude products are described herein.
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Dry, rough and unmanageable curls can turn the best of days into a bad hair day. Protect your hair with SheaMoistures High Porosity Moisture-Seal Masque formulated using ultra-hydrating Mongongo and Hemp Seed Oils to transform porous, over processed , damaged hair into soft, smooth, frizz-free curls and coils.High Porosity hair shaft cuticles are open causing the hair to lose moisture almost as soon as it is absorbed. Low moisture retention causes split ends, makes your curls rough, dry and prone to breakage. SheaMoistures High Porosity Moisture-Seal Masque is enriched with Mongongo and Hemp Seed Oils which seals in moisture by closing hair cuticles, forming a protective layer over your curls, leaving you hair bouncy, nourished and oh-so-amazing!SheaMoistures High Porosity Moisture-Seal Masque is fortified with natural ingredients like Baobab Proteins, Apple Cider Vinegar and certified organic Shea Butter which smooths down the cuticles of the hair shaft leaving you hair moisturized, smooth and
Swelling of Cellulosic Porous Materials - Mathematical Description and Verification. Anton Geffert,a,* Ondrej Vacek,b Andrej Jankech,b Jarmila Geffertová,a and Miloslav Milichovský c. The swelling of natural porous materials, including bleached pulp, as represented by mathematical descriptions, is influenced by a variety of different operating factors. The formerly used Generalised Hygroscopicity Model leads to either a disproportion between a model and a limit value of the sorption capacity or to noticeable deviation in the early swelling phase. Alternatively, the so-called Simple Bounded Growth model solely depends on the maximum sorption capacity, ignoring the physical properties that affect the fibre swelling rate. This research shows that the combination of the two models best describes the swelling process of bleached pulp - a rapid swelling phase and a slower swelling phase. The combined model was found to be useful in characterizing the well-known hornification process.. Contact ...
TY - GEN. T1 - The role of surface chemistry and porosity on the adsorption of inflammatory mediators. AU - Murphy, M. C.. AU - Phillips, G. J.. AU - Lloyd, A. W.. AU - Davies, J. G.. AU - Mikhalovsky, S. V.. PY - 2004/12/1. Y1 - 2004/12/1. N2 - The role of surface chemistry and porosity on the adsorption of inflammatory mediators was analyzed. It was found that the removal of lipopolysaccharide (LPS) and proinflammatory cytokines from the circulation was capable of providing a therapy to counteract sepsis. It was observed that all MAST carbons exhibited poor adsorption capability for LPS. The results show that porosity is helpful in the adsorption of LPS.. AB - The role of surface chemistry and porosity on the adsorption of inflammatory mediators was analyzed. It was found that the removal of lipopolysaccharide (LPS) and proinflammatory cytokines from the circulation was capable of providing a therapy to counteract sepsis. It was observed that all MAST carbons exhibited poor adsorption ...
Hair care tips for high porosity hair are very important. If your hair is low porosity, then its not going to have any problems with hair growth. However, if your hair is high porosity, then you need to take special measures to make sure that your hair grows properly. For example, if youre having trouble growing out your locks because theyre too coarse or thick and heavy, then there might be some things that can help you get rid of these issues.. The main thing is that you need to know what to do so that your hair doesnt become brittle or break off. Also, if you want to keep your hair healthy and strong, then you need to take proper care of it.. You dont want it breaking easily when doing physical activities like running around or working out.. There are various ways to deal with the problem of high porosity hair. Some of them include:. 1) Use a product containing proteins such as casein or soy protein.. These types of products will help your hair retain moisture better and prevent damage ...
Porous materials have application in adsorption based processes due to their high internal surface area and tailorable pore size. They find uses in fields such as catalysis, separation, biotechnology, and microelectronics. Fluids confined in such materials exhibit interesting behavior in regards to the condensation and evaporation mechanisms. Understanding study the behavior of fluids confined in these porous materials is necessary for the efficient design of these materials. The adsorption/desorption isotherm provides valuable information about the effect of network features like pore connectivity and pore size distribution on fluid behavior during pore condensation and evaporation. Such insight can be useful in the characterization of these porous materials. Three dimensionally ordered mesoporous (3DOm) carbon is a porous material that has recently emerged and is of interest. These porous structures are obtained from templating colloidal crystals formed from lysine-silica nanoparticles. The resulting
TY - JOUR. T1 - Molecular simulation study on adsorption of methanol/water mixtures in mesoporous silicas modified pore surface silylation. AU - Aoyama, Naoki. AU - Yoshihara, Tsukasa. AU - Furukawa, Shin ichi. AU - Nitta, Tomoshige. AU - Takahashi, Hideaki. AU - Nakano, Masayoshi. N1 - Funding Information: The research was partly supported by a Grant-in-Aid for Young Scientists (B) (No. 17760600) from the Ministry of Education, Science, Sports and Culture, Japan.. PY - 2007/8/25. Y1 - 2007/8/25. N2 - Two types of molecular simulation techniques have been utilized to investigate adsorption of methanol/water mixtures in a mesoporous silica with a hydrophobic pore surface: the NVT-ensemble Molecular Dynamics method with the melt-quench algorithm for modeling a fully-silylated mesoporous silica and the μVT-ensemble Orientaional-Biased Monte Carlo method for calculating adsorption isotherms. Adsorption isotherms of methanol and water at 333 K are calculated for an equi-relative-pressure mixture ...
Treat rough, unmanageable, damaged or dry hair with High Porosity Moisture-Seal Shampoo from SheaMoisture. This sulfate-free highly moisturizing shampoo is specially formulated for deep thorough cleansing of scalp and rough, damaged curls and coils prone to frizz, dryness and breakage.Dry hair, dehydrated and low moisture hair, feels rough, is frizzy or dull with split-ends and is shedding. This ultra-moisture rich shampoo wont strip, tangle or dry out your hair. SheaMoistures High Porosity Moisture-Seal Shampoo is enriched with Mongongo and Hemp Seed Oils, which repairs damage and seals moisture into your hair cuticles making your curls or coils feel smooth and nourished.Natural ingredients like Baobab Proteins and Apple Cider Vinegar have been blended together with certified organic Shea Butter to create a rich formula which gently smooths porous, rough or hair over-processed from color treatments or perms. SheaMoistures High Porosity Moisture-Seal Shampoo is formulated with ultra-hydrating
The Test: Many, many people on the internet have tried simple tests for porosity. Of all the methods I have seen, I think the following method gives you most accurate results. To determine your hair porosity level using water, spritz a small section of curls with water and watch how your hair reacts - does your hair absorb the water quickly (indicating high porosity) or does it remain on top (indicating a low porosity level).. Normal Porosity: These are the lucky curls. It accepts and retains moisture inside the cuticle. The curls are full of bounce and elasticity and hold styles well. This hair can be dyed easily, and usually requires very little maintenance. Avoid using heat styling tools. When you do use hot tools, use a thermal protectant. Natural or Sulfate-free shampoos and conditioners are good to use. Leave in conditioners can be used to cure fly-aways.. High porosity: I used to have highly porose hair. High porosity hair can be a real pain. Symptoms of high porosity hair could be that ...
Dupont, Thomas, Leclaire, Philippe et Panneton, Raymond. 2013. « Acoustic methods for measuring the porosities of porous materials incorporating dead-end pores ». Journal of the Acoustical Society of America, vol. 133, nº 4. pp. 2136-2145 ...
When a porosity problem occurs, you first need to determine the type of porosity. Porosity is symbolized in phi (Ï ) and its value is expressed in percentage. And that means that women with high porosity hair will find that their hair responds well to many different types and sizes of proteins. High porosity values indicate high capacities of the reservoir rocks to contain these fluids, while low porosity values indicate the opposite. Similarly, the definitions of the standard densities associated with rocks then follows: Typically porosity is a limited space devoid of metal where gas was trapped during solidification. Factors Affecting Porosity of Soil. Types of Pores in Soil 3. Unless otherwise ascribed many of the other diagrams and the photomicrographs were created by Christopher Kendall. The porosity classification guide can help you determine the porosity type. They can do protein treatments more often and see beautiful hair from it. The bulk of mineral content is made of clay, silt and sand,
You should also note that:. Even though your hair may be predominantly one type of porosity, some strands would be a different porosity. Secondly, one strand may be one porosity at the roots and another at the ends. For example, I think my hair is mostly high porosity but there might be some normal porosity strands. I have also noticed that my roots are normal porosity but my ends are high porosity. Hair care can be so confusing! In my next post, I will be talking more in-depth about determining your hair porosity and after that managing each of the porosity types. ...
In a disposable absorbent garment, an absorbent structure includes liquid absorbing material comprising an upper layer comprising preferably softwood fibers and having a density from about 0.03 to about 0.14 g/cc, a lower layer comprising preferably hardwood fibers, formed substantially separately from and underlying at least a portion of the upper layer, the second layer having top and bottom surfaces, a density from about 0.14 to about 0.3 g/cc, a total void volume greater than about 80%, an average pore size distribution generally less than the average pore size distribution of the upper layer. There is an overlap in the pore size distributions of the upper and lower layers such that the smallest pores in the upper layer are smaller than the largest pores in the lower layer and front and rear fluid storage pouches, preferably spaced from one another at the front one-third and rear one-third of the absorbent structure, respectively, each pouch comprise superabsorbent material disposed in a hydrophilic
In this communication, we present a novel approach for control of drug release from porous materials. The method is based on deposition of a plasma polymer layer with controlled thickness which reduces a pore diameter and, hence, defines the rate of drug release.
The transport of electrolytes across varying section channels or porous material is of paramount importance due to its relevance in diverse fields spanning from biology to oil extraction. Clearly in these scenarios the shape of the porous media or the ionic channel is crucial in determining the transport properties of the electrolyte, or viceversa, for every channel shape it is possible to identify an optimal protocol that maximizes the transport. In this seminar, we will present a simplified approach capable of capturing the role of the shape of the container in the overall transport. By means of our simplified approach we will show that novel dynamical regimes can be attained when the Debye length is comparable to the channel bottleneck. ...
The transport of electrolytes across varying section channels or porous material is of paramount importance due to its relevance in diverse fields spanning from biology to oil extraction. Clearly in these scenarios the shape of the porous media or the ionic channel is crucial in determining the transport properties of the electrolyte, or viceversa, for every channel shape it is possible to identify an optimal protocol that maximizes the transport. In this seminar, we will present a simplified approach capable of capturing the role of the shape of the container in the overall transport. By means of our simplified approach we will show that novel dynamical regimes can be attained when the Debye length is comparable to the channel bottleneck. ...
Porous Materials Incorporated has six product lines and manufactures over thirty different instruments. In addition, we hold several US and International patents on novel technology for characterization of pore structure. ...
Numerical simulation with progressive damage criterion is implemented to investigate the effect of porosity on the bending properties of 2D cross-ply carbon/carbon (C/C) composites. The mechanical properties of Pyrocarbon matrix regarding the change of porosity are calculated by using Mori-Tanaka approach. Combining with the stiffness degradation scheme, the ultimate bending strengths are calculated in Abaqus though a user-defined subroutine (USDFLD). Delamination is modelled by inserting cohesive elements between two adjacent plies. A good agreement is obtained when the FEM results are compared to three-point bending experiments. The FEM results show that the bending strength decreases greatly with the increase of porosity. When the porosity reaches up to 18%, the bending strength is decreased by 57%. The major fracture behaviors are interlamination delamination and continuous crack damage in 90° plies. With the increase of porosity, more severe interlamination delamination will be slightly ...
Summary: The aim of this paper was to investigate and analyze microwave and convection drying kinetics of porous materials on laboratory scale. A wet clay plate was chosen as a representative of porous materials. General statements as regards a drying process, whether on a theoretical or analytical level, phenomenological or empirical, still presents on open issue. This is specially true for microwave drying. Modelling was based on elementary layer theory adapted to practical cases of wet plates drying of porous materials both in a laboratory convection dryer and laboratory test apparatus for microvave drying. During the drying process of shaped porous materials, it is inevitable to have knowledge of maximum allowed drying rate curve which can be only obtained by experimentation. Taking this into account special attention was payed to finding out the maximum allowed drying rate curve both for convection and microwave drying. It is, thereby, necessary to have a model that can sufficiently ...
This innovative reference collects state-of-the-art procedures for the construction and design of nanoparticles and porous material while suggesting appropriate
Mercury intrusion porosimetry is a valuable method for characterizing relative pore space dimensions. This dynamic technique is based on the intrusion of mercury into a porous structure under stringently controlled pressures. Mercury intrusion porosimetry permits the calculation of numerous sample properties such as pore size distributions, total pore volume, total pore surface area, median pore throat diameter, and sample densities (bulk and skeletal).. Capillary behavior and permeability are critical to reservoir behavior. Porosimetry is among the few techniques capable of probing the fine connected pore space of shales. This method is particularly useful in evaluation reservoir quality variations within a shale play and in petrotyping shale (Kale et al., 2010, Society of Petroleum Engineer).Various empirical transforms can be applied to estimate permeability from mercury intrusion data. While not quantitative, these estimates can provide a relative assessment of the variation in permeability. ...
Finden Sie alle Bücher von Fleys Matthieu - Water Behavior in Hydrophobic Porous Materials. Bei der Büchersuchmaschine eurobuch.de können Sie antiquarische und Neubücher VERGLEICHEN UND SOFORT zum Bestpreis bestellen. 9783639091427
Disclosed herein are textured nonwoven wiper materials. The textured nonwoven wiper material includes a meltblown nonwoven web material that has a first exterior surface and a second exterior surface, and at least the first exterior surface of the meltblown nonwoven web is a three-dimensional textured surface. The textured meltblown nonwoven web has a multi-modal pore size distribution that includes at least two major pore size peaks.
INTENDED USE: Nanoil For High Porosity Hair is one of the three oils available in the range. The high porosity version is designed to rebuild, moisten, beautify and protect dry, damaged hair. Nanoil will also take care of the dry sensitive and irritated scalp. COMPOSITION AND EFFECTS: Nanoil nourishes the scalp and bulbs and the […]
Shape-Anchored Porous Polymer Monoliths for Integrated Online Solid-Phase Extraction-Microchip Electrophoresis-Electrospray Ionization Mass Spectrometry ...
S. Inagaki, Y. Fukushima, Hikaru Doi, O. Kamigaito; Pore size distribution and adsorption selectivity of sepiolite. Clay Minerals ; 25 (1): 99-105. doi: https://doi.org/. Download citation file:. ...
The effect of the pore size distribution on size-resolved filtration efficiency was investigated for two ceramic particulate filters using
Causse, P. et Trochu, F.. 2018. « Combined characterization of pore size distribution and permeability in fibrous textiles by capillary flow porometry ». In 14th International Conference on Flow Processing in Composite Materials (Lulea, Switzerland, May 30 - June 01, 2018 ...
The present invention provides a porous thermal regenerator apparatus and method of making a porous thermal regenerator comprised of metallic or intermetallic particles that are held together in a porous three dimensional network by a binding agent (such as epoxy). One aspect of the apparatus is that the porosity of the porous thermal regenerator is greater than the tapped porosity of the particles comprising the porous thermal regenerator; moreover, the high-porosity apparatus is durable, that is, it remains intact when exposed to strong time-varying magnetic forces while immersed in aqueous fluid. This high porosity, when combined with high strength and aqueous heat transfer fluid stability, leads to improved porous thermal regenerators and concomitantly to magnetic refrigerators with improved performance.
Porosity sealing , is the process of filling a porous substrate to make it airtight . Porosity is sealed through the process of vacuum impregnation . Vacuum impregnation is the preferred method for sealing parts to prevent fluids or gases from leaking under pressure. Vacuum impregnation seals porosity and leak paths that form during the casting or molding process. It does so without changing the castings' dimensional or functional characteristics and allows manufacturers to use parts that would otherwise be scrapped. There are three types of porosity; Flow Porosity, Gas Porosity and Shrink Porosity. Porosity is found in many cast metal components, but it commonly found in aluminium and magnesium die castings. Process Porosity sealing is a four-step process: In the impregnation chamber (also known as an autoclave, pressure vessel or vacuum vessel) air is evacuated from the leak path in the part by using a deep vacuum. The evacuated leak path is filled with sealant by covering the part with the
The influence of porosity on the superconducting properties have been investigated on YBa/sub 2/Cu/sub 3/O/sub 7/ thin films deposited on LaAlO/sub 3/ [100] substrates by the so-called Trifluoroacetate (TFA) route. Micro-Raman spectroscopy have been used to determine the concentration of c-axis grains /spl delta/ in different samples and their influence on the final film porosity as observed from SEM imaging. This has been compared with measurements of resistivity and critical currents in the same samples. We prove that this /spl delta/ fraction is the main parameter controlling the porosity and hence the normal-state resistivity of the thin films. The optimization of the microstructure of these YBa/sub 2/Cu/sub 3/O/sub 7/ TFA films allow to have high critical currents : J/sub c/ = 3 /spl times/ 10/sup 6/ A/cm/sup 2/ at 77 K ...
We present here some evidences that capillary liquid bridges are able to deform micrometric cylindrical pores by tensile stress. Brine-soaked filter membranes are submitted to drying conditions leading to NaCl precipitation inside the 5-10 μm pores. A close examination demonstrated that two forms of NaCl crystallites are successively generated. First, primary cubic crystals grow, driven by the permanent evaporation. When this angular primary solid gets near the pore wall, while the evaporation makes the pore volume to be partly invaded by air, capillary liquid can bridge the nowsmall gap between the halite angles and the pore wall. In a second step, these small capillary bridges are frozen by a secondary precipitation event of concave-shaped NaCl. The proposed interpretation is that the liquid capillary bridges deform the host matrix of the membrane, and the situation is fossilized by the growth of solid capillary bridges. A quantitative interpretation is proposed and the consequences towards the
Designed For High Porosity hair! Not sure if you have high porosity? Do the test! Take one strand of hair that has fallen out or from your brush and place in a glass of water. Wait a few minutes and if your hair floats you have low porosity hair. If it sinks to the bottom, you have high porosity hair and this product i
TY - JOUR. T1 - Controls on primary porosity and permeability development in igneous rocks. AU - Petford, Nick. PY - 2003. Y1 - 2003. N2 - Some of the more important processes leading to the development of primary igneous porosity due to the cooling and crystallization of magma are reviewed. A distinction is made between volcanic and plutonic rocks, and crystalline and granular volcanic material. Porosity in each rock type is classified according to a proposed effective length scale and geometry into diffusive (Class D) and macroscopic flow (Class F) features. Estimated ranges in values of porosity and permeability are given for a wide selection of igneous rock types, and comparison is made with permeability variations (Δk) derived for both the continental and oceanic crust. While fracture porosity is dominant in most crystalline materials, primary porosity development may play an important role in the final (total) porosity in igneous basement. Some types of primary porosity and permeability ...
Use of Capillary Pressure Data and Log Calculated Water Saturation for the Characterization of Dual Porosity, Dual Permeability Systems. This paper describes a simple method to divide the effective porosity values that can be calculated from log analysis into two flow media (fracture and matrix) pore volumes for use in numerical simulation models. The division of the porosity is based on the assumption that the total porosity of the system is made up from two contributing rock types or lithofacies that have distinct pore size and/or pore size distribution such that they can be represented by different capillary pressure functions. This assumption is applicable to the non-fractured as well as to the fractured systems.. When the method is used for the fractured systems, the fracture is typically represented by a zero capillary pressure value (gravity segregation). The matrix has its own laboratory measured capillary pressure curve. Based on a predetermined water-hydrocarbon contact and using the ...
American Society for Testing and Materials (1999) Standard Test Method for Determination of Pore Volume and Pore Volume Distribution of Soil and Rock by Mercury Intrusion Porosimetry, Designation D 4404-84 (Reapproved 1992). Annual Book of ASTM Standards, 04.08, 588-592.
A porous object includes a porous material having internal pore surfaces and external pore surfaces. Releasing material encapsulated biomolecules are immobilized on at least one of the internal pore surfaces, at least one of the external pore surfaces, or combinations thereof.
The present invention provides biosensor test devices for measuring the presence or amount of an analyte in a biological fluid. The devices have a base plate that has an electrode system embedded therein, and a hydrophilic porous material situated on the base plate. A hydrophobic protective layer is situated on the hydrophilic porous material, and a cover is placed on the hydrophobic protective layer to complete the device. Some embodiments also use an insulating layer, which can be situated between the base layer and the hydrophilic porous material. The cover of the device has an opening present therein, situated over the electrodes, so that the electrodes communicate with the exterior of the device through the groove. The insulating layer can also have a groove situated therein, which in one embodiment is placed to align with the groove in the cover. The invention also provides methods of manufacturing the devices, and methods of using them.
Summary: The development of new porous materials is critical to improving important gas storage and separations applications, and will have a positive impact on reducing greenhouse gases. This includes the deployment of methane and/or hydrogen gases as alternative fuels, development of new filters for removing trace gaseous contaminants from air, and separation of carbon dioxide from flue gas to mitigate greenhouse emissions from the burning of fossil fuels. Dr. Wilmers grant will enable his lab to utilize computational methods to probe the limits of material performance for physical adsorption to porous materials. Although past computational screening has suggested physical limits of adsorption capacity for metal-organic frameworks (MOFs), this project will explore the novel use of so-called pseudomaterials, which represent all potential atomistic arrangements of matter in a porous material ...
Meso-Architecture Block Copolymers with High Surface Area Styrene-Bridged Organosilica Particles as Constituent for the Stimuli-Responsive Remediation of Water
The comparison of pore size distributions obtained with the use of two porosimetric methods: low temperature nitrogen sorption (LN2) and positron annihilation lifetime spectroscopy (PALS), was performed for porous silica monoliths. Four investigated samples were prepared under various synthesis conditions. Nitrogen sorption showed the presence of bottle-shaped pores in all investigated samples. In addition, it seems that the presence of methanol during synthesis influences porosity to a greater extent than organic additives. Quite good agreement between the LN2 and PALS results was observed only for the silica monolith synthesized with β-cyclodextrins as pore directing agent. The biggest discrepancy in the results obtained from these two techniques was observed for the silica gel synthesized with no additives. The origin of such discrepancies, taking into account the shape of pore size distribution and deficiencies of data analysis techniques, is discussed ...
The volume of the voids of a soil over the total volume of the sample defines the porosity of a soil. Used in geology, hydrogeology, soil science, and building science, the porosity of a porous medium (such as rock or sediment) describes the fraction of void space in the material, where the void may contain. Porosity is a fraction between 0 and 1, typically ranging from less than 0.01 for solid granite to more than 0.5 for peat and clay. It may also be represented in percent terms by multiplying the fraction by 100. Porosity is the ratio of pore volume to its total volume. Porosity is controlled by: rock type, pore distribution, cementation, diagenetic history and composition. Porosity is not controlled by grain size, as the volume of between-grain space is related only to the method of grain packing.
Hair that has a high porosity tends to have raised cuticles and the hair too-readily absorbs moisture. Overly-porous hair also releases moisture easily, thus; becoming dry and prone to damage. Perms and straighteners will process much faster in high-porosity hair. Having highly porous hair does not mean your hair is damaged, it just means you have to use different methods when taking care of it ...
Polymer-derived nanoporous carbon materials with high thermal stability, high surface area and narrow pore size distribution have been widely used as catalyst supports. Catalyst performance (activity and selectivity) is significantly affected by the pore size and porosity of the carbon support. Mass transfer limitation inside the pores and steric hindrance imposed by the pore walls can enhance catalyst selectivity and alter reaction kinetics. In this study, platinum embedded in nanoporous carbon spheres was used as a shape selective catalyst for liquid phase hydrogenation of alkenes. Experimental data obtained for different synthesized catalysts with different porosity and pore sizes were used to estimate kinetic parameters (Langmuir-Hinshelwood) and diffusion coefficients for different reactants and products inside the pores, using numerical solution of reaction-diffusion equation. It was shown that adsorption equilibrium constants and reaction rate constants are larger inside the nanopores of ...
The consolidation and permeability characteristics of high porosity surficial sediments from the Coastal Benthic Boundary Layer (Naval Research Laboratory) Special Research Program test site in the EckemfOrde Bay Baltic Sea were studied using a backpressured, constant rate of deformation (CRD) consolidation and permeability testing system driven by flow pumps The silty clay sediments from the Baltic test site are characterized by high void ratios (above 6), large organic content and dissolved or free methane gas bubbles. The high organic content (up to 17%) influences several of the unique features of these sediments including high water contents (up to 500%; porosities up to 93%), high consistency limits and high compressibility. The sediments are dominated by clay and silt size fractions (42% and 55% respectively) with a small percentage (3%) of sands. Organic content determinations performed on selected samples indicated a variation from 9% to 17% in the organic fraction (dry weight basis). Atterberg
PRO-MIX® HP, with its high perlite content, provides a growing environment which benefits growers looking for significant drainage capacity, increased air porosity and lower water retention. The added benefit of a fibrous peat moss and coarse perlite makes this formulation ideal for growers demanding a superior quality product adapted to their needs for watering flexibility and crop seasonality. HP=high porosity. ...
A matrix including: a) a polymeric base matrix including macropores (pore system 1) and b) an interior material, possibly porous (pore system 2), retained within the macropores. The matrix is characterized in that there is a continuous free volume between the interior material and the pore walls of the macropores. A method for manufacturing a matrix including a base matrix having macropores in which an interior material is located. The method is characterized in including the steps: (I) providing a base matrix having macropores; (ii) filling the macropores with a soluble form of the interior material; (iii) transforming the insoluble from to an insoluble form; (iv) shrinking the insoluble form; and (v) irreversibly stabilizing the material in its shrunken form. The matrix can be used in separation methods, cell culturing, solid phase synthesis of organic molecules, and in catalytic reactions (such as enzyme reactions) and other uses in which porous support matrices are used.
Foil Kite Coating - Improving Porosity Last post by kitexpert « Mon May 03, 2021 9:19 pm ...
Perhaps a lot of porosity? Looking forward to the return of the samples. ...
Associated knowledgebase article : Glass Fiber Filter Disc Porosity Chart InstathermInstructions.pdf (File Size : 204.1 KB, ...
Glass Fiber Filter Disc Porosity Chart. 82079. Stir Shaft Quick Reference Chart. 105165. ...
It does have a small leak through the block from porosity. I replaced the clutch and pressure plate while I had the engine out ...
Zero cell porosity in v5.0 =, modify array c_solid_flag Last post by C.FLAG. « Tue Oct 30, 2018 2:18 pm. Posted in code_saturne ...
I think Ive noticed some porosity in one plate, but I never etched it and checked under a microscope to be sure. Should have ...
... but dont try to explain porosity to a welder, if you know what I mean. And I think you do.. Which brings me to my next point. ...
In this context one must take note that, generally speaking, high porosity fabric makes for a more stable parachute and a lower ...
Soil porosity Last post by GES DISC - jimacker « Fri Apr 16, 2021 3:54 pm America/New_York ...
Soil porosity Last post by GES DISC - jimacker « Fri Apr 16, 2021 3:54 pm America/New_York ...
Soil porosity Last post by GES DISC - jimacker « Fri Apr 16, 2021 3:54 pm America/New_York ...
I believe the question at this point is: does the porosity or texture of a stone somehow improve the final product as compared ... I believe the question at this point is: does the porosity or texture of a stone somehow improve the final product as compared ...
Porosity analysis in advanced materials for aero engines. S.-M. Rauscher, A. Raina, I. Kaleel ...
Omega dual-porosity model water content mass transfer Last post by Jirka « Fri Aug 27, 2021 9:44 am ... dual porosity conc. flux bc Last post by Jirka « Fri Apr 30, 2021 8:25 pm ...
Mixing factor in dual porosity model Started by Olasz Tamas 0 Replies 418 Views April 21, 2020, 11:10:19 AM. by Olasz Tamas ...
of micro porosities ... Read More .... micro hot rod mill - miningbmw.com. Micro Hot Rod Mill For Sale - anooprchandra.in Oct. ...
Porosity Issues in High Pressure DieCasting of Engine Blocks Last post by Speeder « Fri Aug 03, 2018 4:43 pm. ...
BIO 1 is adapted to each surgery with several shapes and porosities. ...
  • Coverage depends on the porosity, type and texture of the surface. (uk.com)
  • and chalcocite, Cu2S) is a complex mineral replacement reaction where the reaction pathway is controlled by the interplay between evolving mineral make-up, texture/porosity, and solution chemistry. (amiminerals.it)
  • Hi Robin, to enter an intrinsic porosity of a material phase into a diffusivity simulation, use the Simulate Diffusion Experiment -option. (math2market.de)
  • Dec 14, 2019 · DIN 1.0037 (material St37-2 ) equivalent to US ASTM AISI SAE, European standard EN, British standard BSI, France standard NF, ISO standard, Japanese standard JIS, Chinese GB standard and Indian IS standard. (un-bonbon-sale-par-terre.fr)
  • St37-2 steel (1.0037 material) is an unalloyed structural steel grade complies with DIN 17100 1980 and has been discarded since 2004.According to German standard DIN 17100,St37 steel is divided into St37-2,USt37-2,RSt37-2 and St37-3.Material St 37 new designation is S235,and St37-2 new designation is S235JR (1.0038),the new standard is EN 10025-2 2004. (rotulosaviles.es)
  • In the Edit-menu you can now enter the effective values either in terms of effective diffusivity or in terms of effective porosity and tortuosity. (math2market.de)

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