A change of a substance from one form or state to another.

An order of large, long-necked, long-legged, flightless birds, found in South America. Known as rheas, they are sometimes called American ostriches, though they are in a separate order from true OSTRICHES.

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)

Fractionation of a vaporized sample as a consequence of partition between a mobile gaseous phase and a stationary phase held in a column. Two types are gas-solid chromatography, where the fixed phase is a solid, and gas-liquid, in which the stationary phase is a nonvolatile liquid supported on an inert solid matrix.

Liquid chromatographic techniques which feature high inlet pressures, high sensitivity, and high speed.

Miniaturized methods of liquid-liquid extraction.

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)

The mixture of gases present in the earth's atmosphere consisting of oxygen, nitrogen, carbon dioxide, and small amounts of other gases.

A phase transition from liquid state to gas state, which is affected by Raoult's law. It can be accomplished by fractional distillation.

A group of compounds with the general formula M10(PO4)6(OH)2, where M is barium, strontium, or calcium. The compounds are the principal mineral in phosphorite deposits, biological tissue, human bones, and teeth. They are also used as an anticaking agent and polymer catalysts. (Grant & Hackh's Chemical Dictionary, 5th ed)

Calcium salts of phosphoric acid. These compounds are frequently used as calcium supplements.

Process that is gone through in order for a device to receive approval by a government regulatory agency. This includes any required preclinical or clinical testing, review, submission, and evaluation of the applications and test results, and post-marketing surveillance. It is not restricted to FDA.

Salts that melt below 100 C. Their low VOLATILIZATION can be an advantage over volatile organic solvents.

The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.

The motion of phospholipid molecules within the lipid bilayer, dependent on the classes of phospholipids present, their fatty acid composition and degree of unsaturation of the acyl chains, the cholesterol concentration, and temperature.

The homogeneous mixtures formed by the mixing of a solid, liquid, or gaseous substance (solute) with a liquid (the solvent), from which the dissolved substances can be recovered by physical processes. (From Grant & Hackh's Chemical Dictionary, 5th ed)

Layers of lipid molecules which are two molecules thick. Bilayer systems are frequently studied as models of biological membranes.

Chromatographic techniques in which the mobile phase is a liquid.

Synthetic phospholipid used in liposomes and lipid bilayers to study biological membranes. It is also a major constituent of PULMONARY SURFACTANTS.

The study of CHEMICAL PHENOMENA and processes in terms of the underlying PHYSICAL PHENOMENA and processes.

The scattering of x-rays by matter, especially crystals, with accompanying variation in intensity due to interference effects. Analysis of the crystal structure of materials is performed by passing x-rays through them and registering the diffraction image of the rays (CRYSTALLOGRAPHY, X-RAY). (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)

A water-soluble, colorless crystal with an acid taste that is used as a chemical intermediate, in medicine, the manufacture of lacquers, and to make perfume esters. It is also used in foods as a sequestrant, buffer, and a neutralizing agent. (Hawley's Condensed Chemical Dictionary, 12th ed, p1099; McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed, p1851)

Liquids that dissolve other substances (solutes), generally solids, without any change in chemical composition, as, water containing sugar. (Grant & Hackh's Chemical Dictionary, 5th ed)

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.

Materials in intermediate state between solid and liquid.

Derivatives of phosphatidic acids in which the phosphoric acid is bound in ester linkage to a choline moiety. Complete hydrolysis yields 1 mole of glycerol, phosphoric acid and choline and 2 moles of fatty acids.

The physical phenomena describing the structure and properties of atoms and molecules, and their reaction and interaction processes.

The characteristic three-dimensional shape of a molecule.

Methods of creating machines and devices.

Lipids, predominantly phospholipids, cholesterol and small amounts of glycolipids found in membranes including cellular and intracellular membranes. These lipids may be arranged in bilayers in the membranes with integral proteins between the layers and peripheral proteins attached to the outside. Membrane lipids are required for active transport, several enzymatic activities and membrane formation.

Theoretical representations that simulate the behavior or activity of chemical processes or phenomena; includes the use of mathematical equations, computers, and other electronic equipment.

Characteristics or attributes of the outer boundaries of objects, including molecules.

The principal sterol of all higher animals, distributed in body tissues, especially the brain and spinal cord, and in animal fats and oils.

The ability of a substance to be dissolved, i.e. to form a solution with another substance. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)

Contraceptive devices placed high in the uterine fundus.

A type of stress exerted uniformly in all directions. Its measure is the force exerted per unit area. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)

Freedom of equipment from actual or potential hazards.

The tendency of a gas or solute to pass from a point of higher pressure or concentration to a point of lower pressure or concentration and to distribute itself throughout the available space. Diffusion, especially FACILITATED DIFFUSION, is a major mechanism of BIOLOGICAL TRANSPORT.

Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.

A rigorously mathematical analysis of energy relationships (heat, work, temperature, and equilibrium). It describes systems whose states are determined by thermal parameters, such as temperature, in addition to mechanical and electromagnetic parameters. (From Hawley's Condensed Chemical Dictionary, 12th ed)

Expendable and nonexpendable equipment, supplies, apparatus, and instruments that are used in diagnostic, surgical, therapeutic, scientific, and experimental procedures.

Removal of an implanted therapeutic or prosthetic device.

The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH = log 1/2[1/(H+)], where (H+) is the hydrogen ion concentration in gram equivalents per liter of solution. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)

Elements of limited time intervals, contributing to particular results or situations.

Lipids containing one or more phosphate groups, particularly those derived from either glycerol (phosphoglycerides see GLYCEROPHOSPHOLIPIDS) or sphingosine (SPHINGOLIPIDS). They are polar lipids that are of great importance for the structure and function of cell membranes and are the most abundant of membrane lipids, although not stored in large amounts in the system.

A CATHETER-delivered implant used for closing abnormal holes in the cardiovascular system, especially HEART SEPTAL DEFECTS; or passageways intentionally made during cardiovascular surgical procedures.

Methods utilizing the principles of MICROFLUIDICS for sample handling, reagent mixing, and separation and detection of specific components in fluids.

The rate dynamics in chemical or physical systems.

Devices, not affixed to the body, designed to help persons having musculoskeletal or neuromuscular disabilities to perform activities involving movement.

Products or parts of products used to detect, manipulate, or analyze light, such as LENSES, refractors, mirrors, filters, prisms, and OPTICAL FIBERS.

Artificial substitutes for body parts, and materials inserted into tissue for functional, cosmetic, or therapeutic purposes. Prostheses can be functional, as in the case of artificial arms and legs, or cosmetic, as in the case of an artificial eye. Implants, all surgically inserted or grafted into the body, tend to be used therapeutically. IMPLANTS, EXPERIMENTAL is available for those used experimentally.

Intrauterine contraceptive devices that depend on the release of metallic copper.

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.

A mass spectrometry technique using two (MS/MS) or more mass analyzers. With two in tandem, the precursor ions are mass-selected by a first mass analyzer, and focused into a collision region where they are then fragmented into product ions which are then characterized by a second mass analyzer. A variety of techniques are used to separate the compounds, ionize them, and introduce them to the first mass analyzer. For example, for in GC-MS/MS, GAS CHROMATOGRAPHY-MASS SPECTROMETRY is involved in separating relatively small compounds by GAS CHROMATOGRAPHY prior to injecting them into an ionization chamber for the mass selection.

Failure of equipment to perform to standard. The failure may be due to defects or improper use.

The statistical reproducibility of measurements (often in a clinical context), including the testing of instrumentation or techniques to obtain reproducible results. The concept includes reproducibility of physiological measurements, which may be used to develop rules to assess probability or prognosis, or response to a stimulus; reproducibility of occurrence of a condition; and reproducibility of experimental results.

Artificial respiration (RESPIRATION, ARTIFICIAL) using an oxygenated fluid.

Microdevices that combine microfluidics technology with electrical and/or mechanical functions for analyzing very small fluid volumes. They consist of microchannels etched into substrates made of silicon, glass, or polymer using processes similar to photolithography. The test fluids in the channels can then interact with different elements such as electrodes, photodetectors, chemical sensors, pumps, and valves.

An analytical method used in determining the identity of a chemical based on its mass using mass analyzers/mass spectrometers.

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.

Laws and regulations pertaining to devices used in medicine, proposed for enactment, or enacted by a legislative body.

An agency of the PUBLIC HEALTH SERVICE concerned with the overall planning, promoting, and administering of programs pertaining to maintaining standards of quality of foods, drugs, therapeutic devices, etc.

The study, control, and application of the conduction of ELECTRICITY through gases or vacuum, or through semiconducting or conducting materials. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)

Silicone polymers which consist of silicon atoms substituted with methyl groups and linked by oxygen atoms. They comprise a series of biocompatible materials used as liquids, gels or solids; as film for artificial membranes, gels for implants, and liquids for drug vehicles; and as antifoaming agents.

Intrauterine devices that release contraceptive agents.

The plan and delineation of prostheses in general or a specific prosthesis.

Surgical insertion of a prosthesis.

A mass spectrometry technique used for analysis of nonvolatile compounds such as proteins and macromolecules. The technique involves preparing electrically charged droplets from analyte molecules dissolved in solvent. The electrically charged droplets enter a vacuum chamber where the solvent is evaporated. Evaporation of solvent reduces the droplet size, thereby increasing the coulombic repulsion within the droplet. As the charged droplets get smaller, the excess charge within them causes them to disintegrate and release analyte molecules. The volatilized analyte molecules are then analyzed by mass spectrometry.

Evaluation undertaken to assess the results or consequences of management and procedures used in combating disease in order to determine the efficacy, effectiveness, safety, and practicability of these interventions in individual cases or series.

Determination, by measurement or comparison with a standard, of the correct value of each scale reading on a meter or other measuring instrument; or determination of the settings of a control device that correspond to particular values of voltage, current, frequency or other output.

Vascular filters or occlusive devices that provide mechanical protection of the distal end organ from blood clots or EMBOLISM-causing debri dislodged during ENDOVASCULAR PROCEDURES.

The design or construction of objects greatly reduced in scale.

Techniques for controlling bleeding.

Apparatus used to support, align, prevent, or correct deformities or to improve the function of movable parts of the body.

Devices designed to provide personal protection against injury to individuals exposed to hazards in industry, sports, aviation, or daily activities.

Binary classification measures to assess test results. Sensitivity or recall rate is the proportion of true positives. Specificity is the probability of correctly determining the absence of a condition. (From Last, Dictionary of Epidemiology, 2d ed)

The research and development of ELECTRICAL EQUIPMENT AND SUPPLIES for such medical applications as diagnosis, therapy, research, anesthesia control, cardiac control, and surgery. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)

Nonexpendable items used in examination.

Devices that cause a liquid or solid to be converted into an aerosol (spray) or a vapor. It is used in drug administration by inhalation, humidification of ambient air, and in certain analytical instruments.

A device designed to stimulate, by electric impulses, contraction of the heart muscles. It may be temporary (external) or permanent (internal or internal-external).

The shifting in position or location of an INTRAUTERINE DEVICE from its original placement.

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.

Hand-held tools or implements used by health professionals for the performance of surgical tasks.

A basis of value established for the measure of quantity, weight, extent or quality, e.g. weight standards, standard solutions, methods, techniques, and procedures used in diagnosis and therapy.

Implantable devices which continuously monitor the electrical activity of the heart and automatically detect and terminate ventricular tachycardia (TACHYCARDIA, VENTRICULAR) and VENTRICULAR FIBRILLATION. They consist of an impulse generator, batteries, and electrodes.

Personal devices for protection of the ears from loud or high intensity noise, water, or cold. These include earmuffs and earplugs.

Determination of the spectra of ultraviolet absorption by specific molecules in gases or liquids, for example Cl2, SO2, NO2, CS2, ozone, mercury vapor, and various unsaturated compounds. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)

Types of artificial pacemakers with implantable leads to be placed at multiple intracardial sites. They are used to treat various cardiac conduction disturbances which interfere with the timing of contraction of the ventricles. They may or may not include defibrillating electrodes (IMPLANTABLE DEFIBRILLATORS) as well.

A mixture of metallic elements or compounds with other metallic or metalloid elements in varying proportions.

Spontaneous loss of INTRAUTERINE DEVICES from the UTERUS.

Concentration or quantity that is derived from the smallest measure that can be detected with reasonable certainty for a given analytical procedure.

Procedures in which placement of CARDIAC CATHETERS is performed for therapeutic or diagnostic procedures.

A chromatography technique in which the stationary phase is composed of a non-polar substance with a polar mobile phase, in contrast to normal-phase chromatography in which the stationary phase is a polar substance with a non-polar mobile phase.

Developmental abnormalities in any portion of the ATRIAL SEPTUM resulting in abnormal communications between the two upper chambers of the heart. Classification of atrial septal defects is based on location of the communication and types of incomplete fusion of atrial septa with the ENDOCARDIAL CUSHIONS in the fetal heart. They include ostium primum, ostium secundum, sinus venosus, and coronary sinus defects.

Migration of a foreign body from its original location to some other location in the body.

Materials that have a limited and usually variable electrical conductivity. They are particularly useful for the production of solid-state electronic devices.

Devices which are used in the treatment of orthopedic injuries and diseases.

Apparatus, devices, or supplies intended for one-time or temporary use.

The development and use of techniques to study physical phenomena and construct structures in the nanoscale size range or smaller.

Studies to determine the advantages or disadvantages, practicability, or capability of accomplishing a projected plan, study, or project.

Any of a variety of procedures which use biomolecular probes to measure the presence or concentration of biological molecules, biological structures, microorganisms, etc., by translating a biochemical interaction at the probe surface into a quantifiable physical signal.

Devices capable of receiving data, retaining data for an indefinite or finite period of time, and supplying data upon demand.

Electric conductors through which electric currents enter or leave a medium, whether it be an electrolytic solution, solid, molten mass, gas, or vacuum.

Electrical devices that are composed of semiconductor material, with at least three connections to an external electronic circuit. They are used to amplify electrical signals, detect signals, or as switches.

Devices to be inserted into veins or arteries for the purpose of carrying fluids into or from a peripheral or central vascular location. They may include component parts such as catheters, ports, reservoirs, and valves. They may be left in place temporarily for therapeutic or diagnostic purposes.

Nonexpendable items used in the performance of orthopedic surgery and related therapy. They are differentiated from ORTHOTIC DEVICES, apparatus used to prevent or correct deformities in patients.

Any device or element which converts an input signal into an output signal of a different form. Examples include the microphone, phonographic pickup, loudspeaker, barometer, photoelectric cell, automobile horn, doorbell, and underwater sound transducer. (McGraw Hill Dictionary of Scientific and Technical Terms, 4th ed)

Devices that control the supply of electric current for running electrical equipment.

A microanalytical technique combining mass spectrometry and gas chromatography for the qualitative as well as quantitative determinations of compounds.

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)

Laboratory and other services provided to patients at the bedside. These include diagnostic and laboratory testing using automated information entry.

Compounds formed by the joining of smaller, usually repeating, units linked by covalent bonds. These compounds often form large macromolecules (e.g., BIOPOLYMERS; PLASTICS).

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].

Devices used in the home by persons to maintain dental and periodontal health. The devices include toothbrushes, dental flosses, water irrigators, gingival stimulators, etc.

An extraction method that separates analytes using a solid phase and a liquid phase. It is used for preparative sample cleanup before analysis by CHROMATOGRAPHY and other analytical methods.

A broad family of synthetic organosiloxane polymers containing a repeating silicon-oxygen backbone with organic side groups attached via carbon-silicon bonds. Depending on their structure, they are classified as liquids, gels, and elastomers. (From Merck Index, 12th ed)

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)

Application of principles and practices of engineering science to biomedical research and health care.

Observation of a population for a sufficient number of persons over a sufficient number of years to generate incidence or mortality rates subsequent to the selection of the study group.

The application of electronic, computerized control systems to mechanical devices designed to perform human functions. Formerly restricted to industry, but nowadays applied to artificial organs controlled by bionic (bioelectronic) devices, like automated insulin pumps and other prostheses.

The use of computers for designing and/or manufacturing of anything, including drugs, surgical procedures, orthotics, and prosthetics.

The continuous measurement of physiological processes, blood pressure, heart rate, renal output, reflexes, respiration, etc., in a patient or experimental animal; includes pharmacologic monitoring, the measurement of administered drugs or their metabolites in the blood, tissues, or urine.

Any liquid or solid preparation made specifically for the growth, storage, or transport of microorganisms or other types of cells. The variety of media that exist allow for the culturing of specific microorganisms and cell types, such as differential media, selective media, test media, and defined media. Solid media consist of liquid media that have been solidified with an agent such as AGAR or GELATIN.

The chemical and physical integrity of a pharmaceutical product.

Apparatus and instruments that generate and operate with ELECTRICITY, and their electrical components.

Nonexpendable apparatus used during surgical procedures. They are differentiated from SURGICAL INSTRUMENTS, usually hand-held and used in the immediate operative field.

Any of various animals that constitute the family Suidae and comprise stout-bodied, short-legged omnivorous mammals with thick skin, usually covered with coarse bristles, a rather long mobile snout, and small tail. Included are the genera Babyrousa, Phacochoerus (wart hogs), and Sus, the latter containing the domestic pig (see SUS SCROFA).

Controlled operation of an apparatus, process, or system by mechanical or electronic devices that take the place of human organs of observation, effort, and decision. (From Webster's Collegiate Dictionary, 1993)

The use of electronic equipment to observe or record physiologic processes while the patient undergoes normal daily activities.

Machine readable patient or equipment identification device using radio frequency from 125 kHz to 5.8 Ghz.

Walking aids generally having two handgrips and four legs.

Procedures for collecting, preserving, and transporting of specimens sufficiently stable to provide accurate and precise results suitable for clinical interpretation.

A highly miniaturized version of ELECTROPHORESIS performed in a microfluidic device.

Small computers using LSI (large-scale integration) microprocessor chips as the CPU (central processing unit) and semiconductor memories for compact, inexpensive storage of program instructions and data. They are smaller and less expensive than minicomputers and are usually built into a dedicated system where they are optimized for a particular application. "Microprocessor" may refer to just the CPU or the entire microcomputer.

Surveillance of drugs, devices, appliances, etc., for efficacy or adverse effects, after they have been released for general sale.

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.

The study of chemical changes resulting from electrical action and electrical activity resulting from chemical changes.

A heterogeneous condition in which the heart is unable to pump out sufficient blood to meet the metabolic need of the body. Heart failure can be caused by structural defects, functional abnormalities (VENTRICULAR DYSFUNCTION), or a sudden overload beyond its capacity. Chronic heart failure is more common than acute heart failure which results from sudden insult to cardiac function, such as MYOCARDIAL INFARCTION.

Substances used for the detection, identification, analysis, etc. of chemical, biological, or pathologic processes or conditions. Indicators are substances that change in physical appearance, e.g., color, at or approaching the endpoint of a chemical titration, e.g., on the passage between acidity and alkalinity. Reagents are substances used for the detection or determination of another substance by chemical or microscopical means, especially analysis. Types of reagents are precipitants, solvents, oxidizers, reducers, fluxes, and colorimetric reagents. (From Grant & Hackh's Chemical Dictionary, 5th ed, p301, p499)

Studies in which individuals or populations are followed to assess the outcome of exposures, procedures, or effects of a characteristic, e.g., occurrence of disease.

Systems for the delivery of drugs to target sites of pharmacological actions. Technologies employed include those concerning drug preparation, route of administration, site targeting, metabolism, and toxicity.

The preparation and analysis of samples on miniaturized devices.

A type of MICROCOMPUTER, sometimes called a personal digital assistant, that is very small and portable and fitting in a hand. They are convenient to use in clinical and other field situations for quick data management. They usually require docking with MICROCOMPUTERS for updates.

Use of a balloon CATHETER to block the flow of blood through an artery or vein.

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.

Colloids with a gaseous dispersing phase and either liquid (fog) or solid (smoke) dispersed phase; used in fumigation or in inhalation therapy; may contain propellant agents.

Control of bleeding during or after surgery.

Relating to the size of solids.

Instruments that generate intermittent forces, uniformed or graduated, to facilitate the emptying of VEINS. These devices are used to reduce limb EDEMA and prevent venous THROMBOEMBOLISM, such as deep vein thrombosis in the legs.

Surgical removal of an obstructing clot or foreign material from a blood vessel at the point of its formation. Removal of a clot arising from a distant site is called EMBOLECTOMY.

Studies used to test etiologic hypotheses in which inferences about an exposure to putative causal factors are derived from data relating to characteristics of persons under study or to events or experiences in their past. The essential feature is that some of the persons under study have the disease or outcome of interest and their characteristics are compared with those of unaffected persons.

Synthetic or natural materials, other than DRUGS, that are used to replace or repair any body TISSUES or bodily function.

Studies determining the effectiveness or value of processes, personnel, and equipment, or the material on conducting such studies. For drugs and devices, CLINICAL TRIALS AS TOPIC; DRUG EVALUATION; and DRUG EVALUATION, PRECLINICAL are available.

The utilization of an electrical current to measure, analyze, or alter chemicals or chemical reactions in solution, cells, or tissues.

Use or insertion of a tubular device into a duct, blood vessel, hollow organ, or body cavity for injecting or withdrawing fluids for diagnostic or therapeutic purposes. It differs from INTUBATION in that the tube here is used to restore or maintain patency in obstructions.

Production of an image when x-rays strike a fluorescent screen.

Liquid perfluorinated carbon compounds which may or may not contain a hetero atom such as nitrogen, oxygen or sulfur, but do not contain another halogen or hydrogen atom. This concept includes fluorocarbon emulsions and fluorocarbon blood substitutes.

Devices for continuously measuring and displaying the arterial blood pressure.

Liquids transforming into solids by the removal of heat.

A flexible, tubular device that is used to carry fluids into or from a blood vessel, hollow organ, or body cavity.

Removal of a MEDICAL DEVICE from the market due to a problem occurring in the manufacture or distribution of the product.

Liquid components of living organisms.

Instruments for measuring arterial blood pressure consisting of an inflatable cuff, inflating bulb, and a gauge showing the blood pressure. (Stedman, 26th ed)

The development and use of techniques and equipment to study or perform chemical reactions, with small quantities of materials, frequently less than a milligram or a milliliter.

Detection of drugs that have been abused, overused, or misused, including legal and illegal drugs. Urine screening is the usual method of detection.

Device constructed of either synthetic or biological material that is used for the repair of injured or diseased blood vessels.

Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.

Contraceptive devices used by females.

Insertion of a catheter into a peripheral artery, vein, or airway for diagnostic or therapeutic purposes.

The properties, processes, and behavior of biological systems under the action of mechanical forces.

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.

The study of MAGNETIC PHENOMENA.

Ultrasonic recording of the size, motion, and composition of the heart and surrounding tissues using a transducer placed in the esophagus.

Blocking of a blood vessel by an embolus which can be a blood clot or other undissolved material in the blood stream.

The location of the atoms, groups or ions relative to one another in a molecule, as well as the number, type and location of covalent bonds.

The term "United States" in a medical context often refers to the country where a patient or study participant resides, and is not a medical term per se, but relevant for epidemiological studies, healthcare policies, and understanding differences in disease prevalence, treatment patterns, and health outcomes across various geographic locations.

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)

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.

A system for verifying and maintaining a desired level of quality in a product or process by careful planning, use of proper equipment, continued inspection, and corrective action as required. (Random House Unabridged Dictionary, 2d ed)

The physical effects involving the presence of electric charges at rest and in motion.

Devices intended to replace non-functioning organs. They may be temporary or permanent. Since they are intended always to function as the natural organs they are replacing, they should be differentiated from PROSTHESES AND IMPLANTS and specific types of prostheses which, though also replacements for body parts, are frequently cosmetic (EYE, ARTIFICIAL) as well as functional (ARTIFICIAL LIMBS).

Techniques for securing together the edges of a wound, with loops of thread or similar materials (SUTURES).

Surgically placed electric conductors through which ELECTRIC STIMULATION is delivered to or electrical activity is recorded from a specific point inside the body.

Sharp instruments used for puncturing or suturing.

A procedure consisting of a sequence of algebraic formulas and/or logical steps to calculate or determine a given task.

The motion of fluids, especially noncompressible liquids, under the influence of internal and external forces.

The presence of an infectious agent on instruments, prostheses, or other inanimate articles.

Catheters designed to be left within an organ or passage for an extended period of time.

A type of oropharyngeal airway that provides an alternative to endotracheal intubation and standard mask anesthesia in certain patients. It is introduced into the hypopharynx to form a seal around the larynx thus permitting spontaneous or positive pressure ventilation without penetration of the larynx or esophagus. It is used in place of a facemask in routine anesthesia. The advantages over standard mask anesthesia are better airway control, minimal anesthetic gas leakage, a secure airway during patient transport to the recovery area, and minimal postoperative problems.

Controlled operations of analytic or diagnostic processes, or systems by mechanical or electronic devices.

Analog or digital communications device in which the user has a wireless connection from a telephone to a nearby transmitter. It is termed cellular because the service area is divided into multiple "cells." As the user moves from one cell area to another, the call is transferred to the local transmitter.

An allotropic form of carbon that is used in pencils, as a lubricant, and in matches and explosives. It is obtained by mining and its dust can cause lung irritation.

Malfunction of implantation shunts, valves, etc., and prosthesis loosening, migration, and breaking.

The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.

A small aerosol canister used to release a calibrated amount of medication for inhalation.

Separation of a mixture in successive stages, each stage removing from the mixture some proportion of one of the substances, for example by differential solubility in water-solvent mixtures. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)

A condition in which the FORAMEN OVALE in the ATRIAL SEPTUM fails to close shortly after birth. This results in abnormal communications between the two upper chambers of the heart. An isolated patent ovale foramen without other structural heart defects is usually of no hemodynamic significance.

Homogeneous liquid preparations that contain one or more chemical substances dissolved, i.e., molecularly dispersed, in a suitable solvent or mixture of mutually miscible solvents. For reasons of their ingredients, method of preparation, or use, they do not fall into another group of products.

Devices that help people with impaired sensory responses.

Infections resulting from the implantation of prosthetic devices. The infections may be acquired from intraoperative contamination (early) or hematogenously acquired from other sites (late).

Detection and counting of scintillations produced in a fluorescent material by ionizing radiation.

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.