Rheology: The study of the deformation and flow of matter, usually liquids or fluids, and of the plastic flow of solids. The concept covers consistency, dilatancy, liquefaction, resistance to flow, shearing, thixotrophy, and VISCOSITY.Blood Viscosity: The internal resistance of the BLOOD to shear forces. The in vitro measure of whole blood viscosity is of limited clinical utility because it bears little relationship to the actual viscosity within the circulation, but an increase in the viscosity of circulating blood can contribute to morbidity in patients suffering from disorders such as SICKLE CELL ANEMIA and POLYCYTHEMIA.Erythrocyte Deformability: Ability of ERYTHROCYTES to change shape as they pass through narrow spaces, such as the microvasculature.Hemorheology: The deformation and flow behavior of BLOOD and its elements i.e., PLASMA; ERYTHROCYTES; WHITE BLOOD CELLS; and BLOOD PLATELETS.Viscosity: The resistance that a gaseous or liquid system offers to flow when it is subjected to shear stress. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Erythrocyte Aggregation: The formation of clumps of RED BLOOD CELLS under low or non-flow conditions, resulting from the attraction forces between the red blood cells. The cells adhere to each other in rouleaux aggregates. Slight mechanical force, such as occurs in the circulation, is enough to disperse these aggregates. Stronger or weaker than normal aggregation may result from a variety of effects in the ERYTHROCYTE MEMBRANE or in BLOOD PLASMA. The degree of aggregation is affected by ERYTHROCYTE DEFORMABILITY, erythrocyte membrane sialylation, masking of negative surface charge by plasma proteins, etc. BLOOD VISCOSITY and the ERYTHROCYTE SEDIMENTATION RATE are affected by the amount of erythrocyte aggregation and are parameters used to measure the aggregation.Elasticity: Resistance and recovery from distortion of shape.Hematocrit: The volume of packed RED BLOOD CELLS in a blood specimen. The volume is measured by centrifugation in a tube with graduated markings, or with automated blood cell counters. It is an indicator of erythrocyte status in disease. For example, ANEMIA shows a low value; POLYCYTHEMIA, a high value.Shear Strength: The internal resistance of a material to moving some parts of it parallel to a fixed plane, in contrast to stretching (TENSILE STRENGTH) or compression (COMPRESSIVE STRENGTH). Ionic crystals are brittle because, when subjected to shear, ions of the same charge are brought next to each other, which causes repulsion.Microfluidics: The study of fluid channels and chambers of tiny dimensions of tens to hundreds of micrometers and volumes of nanoliters or picoliters. This is of interest in biological MICROCIRCULATION and used in MICROCHEMISTRY and INVESTIGATIVE TECHNIQUES.Suspensions: Colloids with liquid continuous phase and solid dispersed phase; the term is used loosely also for solid-in-gas (AEROSOLS) and other colloidal systems; water-insoluble drugs may be given as suspensions.Gels: Colloids with a solid continuous phase and liquid as the dispersed phase; gels may be unstable when, due to temperature or other cause, the solid phase liquefies; the resulting colloid is called a sol.Hydrogels: 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)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.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.Erythrocyte Count: The number of RED BLOOD CELLS per unit volume in a sample of venous BLOOD.Factor XIIIa: Activated form of FACTOR XIII, a transglutaminase, which stabilizes the formation of the fibrin polymer (clot) culminating the blood coagulation cascade.Blood Physiological Phenomena: Physiological processes and properties of the BLOOD.Erythrocytes: Red blood cells. Mature erythrocytes are non-nucleated, biconcave disks containing HEMOGLOBIN whose function is to transport OXYGEN.Anemia, Sickle Cell: A disease characterized by chronic hemolytic anemia, episodic painful crises, and pathologic involvement of many organs. It is the clinical expression of homozygosity for hemoglobin S.Microscopy, Atomic Force: A type of scanning probe microscopy in which a probe systematically rides across the surface of a sample being scanned in a raster pattern. The vertical position is recorded as a spring attached to the probe rises and falls in response to peaks and valleys on the surface. These deflections produce a topographic map of the sample.Blood Flow Velocity: A value equal to the total volume flow divided by the cross-sectional area of the vascular bed.Phase Transition: A change of a substance from one form or state to another.Biomechanical Phenomena: The properties, processes, and behavior of biological systems under the action of mechanical forces.Emulsions: Colloids formed by the combination of two immiscible liquids such as oil and water. Lipid-in-water emulsions are usually liquid, like milk or lotion. Water-in-lipid emulsions tend to be creams. The formation of emulsions may be aided by amphiphatic molecules that surround one component of the system to form MICELLES.Biophysics: The study of PHYSICAL PHENOMENA and PHYSICAL PROCESSES as applied to living things.Surface Properties: Characteristics or attributes of the outer boundaries of objects, including molecules.Aphorisms and Proverbs as Topic: Short popular sayings effectively expressing or astutely professing general truths or useful thoughts. (From Random House Unabridged Dictionary, 2d ed, p97, p1556)Encyclopedias as Topic: Works containing information articles on subjects in every field of knowledge, usually arranged in alphabetical order, or a similar work limited to a special field or subject. (From The ALA Glossary of Library and Information Science, 1983)Aphorisms and ProverbsBodily Secretions: Endogenous substances produced through the activity of intact cells of glands, tissues, or organs.Silicates: The generic term for salts derived from silica or the silicic acids. They contain silicon, oxygen, and one or more metals, and may contain hydrogen. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th Ed)Physics: The study of those aspects of energy and matter in terms of elementary principles and laws. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)BooksCosmetics: Substances intended to be applied to the human body for cleansing, beautifying, promoting attractiveness, or altering the appearance without affecting the body's structure or functions. Included in this definition are skin creams, lotions, perfumes, lipsticks, fingernail polishes, eye and facial makeup preparations, permanent waves, hair colors, toothpastes, and deodorants, as well as any material intended for use as a component of a cosmetic product. (U.S. Food & Drug Administration Center for Food Safety & Applied Nutrition Office of Cosmetics Fact Sheet (web page) Feb 1995)Interferometry: Measurement of distances or movements by means of the phenomena caused by the interference of two rays of light (optical interferometry) or of sound (acoustic interferometry).Lasers: An optical source that emits photons in a coherent beam. Light Amplification by Stimulated Emission of Radiation (LASER) is brought about using devices that transform light of varying frequencies into a single intense, nearly nondivergent beam of monochromatic radiation. Lasers operate in the infrared, visible, ultraviolet, or X-ray regions of the spectrum.Journal Impact Factor: A quantitative measure of the frequency on average with which articles in a journal have been cited in a given period of time.Fundus Oculi: The concave interior of the eye, consisting of the retina, the choroid, the sclera, the optic disk, and blood vessels, seen by means of the ophthalmoscope. (Cline et al., Dictionary of Visual Science, 4th ed)Polymers: Compounds formed by the joining of smaller, usually repeating, units linked by covalent bonds. These compounds often form large macromolecules (e.g., BIOPOLYMERS; PLASTICS).Axoneme: A bundle of MICROTUBULES and MICROTUBULE-ASSOCIATED PROTEINS forming the core of each CILIUM or FLAGELLUM. In most eukaryotic cilia or flagella, an axoneme shaft has 20 microtubules arranged in nine doublets and two singlets.Click Chemistry: Organic chemistry methodology that mimics the modular nature of various biosynthetic processes. It uses highly reliable and selective reactions designed to "click" i.e., rapidly join small modular units together in high yield, without offensive byproducts. In combination with COMBINATORIAL CHEMISTRY TECHNIQUES, it is used for the synthesis of new compounds and combinatorial libraries.Refrigeration: The mechanical process of cooling.Lubrication: The application of LUBRICANTS to diminish FRICTION between two surfaces.Lubricants: Compounds that provide LUBRICATION between surfaces in order to reduce FRICTION.Chlorofluorocarbons, Methane: A group of methane-based halogenated hydrocarbons containing one or more fluorine and chlorine atoms.Gas, Natural: A combustible, gaseous mixture of low-molecular weight PARAFFIN hydrocarbons, generated below the surface of the earth. It contains mostly METHANE and ETHANE with small amounts of PROPANE; BUTANES; and higher hydrocarbons, and sometimes NITROGEN; CARBON DIOXIDE; HYDROGEN SULFIDE; and HELIUM. (from McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Patents as Topic: Exclusive legal rights or privileges applied to inventions, plants, etc.Inventions: A novel composition, device, or process, independently conceived de novo or derived from a pre-existing model.Intellectual Property: Property, such as patents, trademarks, and copyright, that results from creative effort. The Patent and Copyright Clause (Art. 1, Sec. 8, cl. 8) of the United States Constitution provides for promoting the progress of science and useful arts by securing for limited times to authors and inventors, the exclusive right to their respective writings and discoveries. (From Black's Law Dictionary, 5th ed, p1014)Photoinitiators, Dental: Chemical compound used to initiate polymerization of dental resins by the use of DENTAL CURING LIGHTS. It absorbs UV light and undergoes decomposition into free radicals that initiate polymerization process of the resins in the mix. Each photoinitiator has optimum emission spectrum and intensity for proper curing of dental materials.Camphor: A bicyclic monoterpene ketone found widely in plants, especially CINNAMOMUM CAMPHORA. It is used topically as a skin antipruritic and as an anti-infective agent.Light: That portion of the electromagnetic spectrum in the visible, ultraviolet, and infrared range.