Chemistry terminology · MLC-0109

Chemistry terms: E (816)

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• EpididymisA coiled tube located on the posterior aspect of each testis, serving as the site for sperm maturation and...
• EpiduralRelating to the anatomical space located between the dura mater, the outermost membrane enveloping the brain...
• EpifaunaAquatic animals, such as barnacles, mussels, or starfish, that live on the surface of a substrate like rock...
• EpigastricRelating to the upper central region of the abdomen, located just below the sternum and above the navel. This...
• EpigeneticRelating to heritable changes in gene function or phenotype that do not involve alterations to the underlying...
• EpihalohydrinsCompounds built on the (halomethyl)oxirane skeleton, an epoxide ring bearing a halomethyl group, as in...
• EpilepsyA chronic neurological disorder characterized by recurrent, unprovoked seizures, which are sudden surges of...
• EpileptiformDescribing electrical activity in the brain that resembles the patterns observed during an epileptic seizure...
• EpimerizationA stereochemical transformation in which one epimer is converted into another. This process involves the...
• EpimersStereoisomers that differ in configuration at only one stereogenic center, while being identical at all other...
• Epi-phaseThe upper liquid layer in a system of two immiscible or partially miscible liquid phases that have separated...
• Epiphyseal plateA cartilaginous growth plate located near the ends of long bones in children and adolescents, responsible for...
• EpisodicDescribing an event or condition that occurs occasionally and at irregular or infrequent intervals, rather...
• EpispadiasA congenital malformation in which the urethra opens on the dorsal surface of the penis in males or near the...
• EpistasisA genetic phenomenon where the expression of one gene is affected by the presence of one or more other genes...
• Episulfonium ionsCationic three-membered rings made of two carbon atoms and one positively charged, trivalent sulfur atom that...
• Epitaxial crystallizationThe process where a polymer crystallizes on the surface of a substrate, with the crystal orientation of the...
• EpitaxyThe growth of a crystalline overlayer on a crystalline substrate, where the crystallographic orientation of...
• EpithalamusA small dorsal posterior segment of the diencephalon, which is a division of the forebrain. It includes the...
• Epithelial-to-mesenchymal transitionA biological process in which polarized epithelial cells, which are normally bound together in a sheet...
• EpitheliomaA tumor originating from epithelial cells, which form the surface layers of the body, line hollow organs, and...
• EpitheliumA type of animal tissue that forms the outer surface of the body and lines internal organs, cavities, and...
• Epithermal neutronsNeutrons whose kinetic energy lies above that of thermal agitation but below the fast range, usually just...
• EpitopeThe specific region of an antigen that is recognized and bound by an antibody or T-cell receptor. This...
• Epitope mappingA technique used to identify the specific amino acid residues or carbohydrate structures on an antigen that...
• Epitope retrievalA laboratory procedure employed to unmask or expose antigenic sites in tissue sections, particularly after...
• Epitope spreadingA phenomenon in which the immune response initially directed against a specific epitope on an antigen...
• EpizooticAn outbreak of disease in an animal population that spreads rapidly and affects a large number of individuals...
• Epoxide hydrolaseAn enzyme that catalyzes the hydrolysis of epoxides, converting them into corresponding trans-dihydrodiols...
• Epoxy compoundsCyclic ethers in which an oxygen atom links two carbon atoms of a chain or ring system, adjacent or not. The...
• Epoxy polymerA class of thermosetting polymers formed by the reaction of an epoxide resin with a hardener or curing agent...
• Epstein-Barr virusA common human herpesvirus (HHV-4) that infects B lymphocytes and epithelial cells, causing infectious...
• Equalization of electronegativity, principle ofSanderson's postulate that when atoms combine, their electronegativities become equal in the molecule, with...
• EquatorialA position occupied by a substituent on a cyclohexane ring that lies approximately in the plane of the ring...
• EquilibrationThe process by which a system reaches a state of equilibrium, where the rates of forward and reverse...
• EquilibriumA state in a chemical system where the rates of the forward and reverse reactions are equal, resulting in no...
• Equilibrium assayA type of biochemical assay designed to measure the concentrations of reactants and products after a system...
• Equilibrium association constantA quantitative measure of the strength of binding between two or more molecules at equilibrium, representing...
• Equilibrium constantA quantity that characterizes a chemical reaction's state of equilibrium, representing the ratio of product...
• Equilibrium dialysateThe solution on one side of a semi-permeable membrane after a dialysis process has reached equilibrium. At...
• Equilibrium dissociation constantA quantitative measure of the propensity of a larger complex to dissociate into its smaller constituent...
• Equilibrium distanceThe internuclear separation between two atoms in a molecule at which the potential energy is at a minimum...
• Equilibrium electrode potentialThe potential difference established between an electrode and its surrounding electrolyte when no net current...
• Equilibrium filmA thin layer of material, such as a liquid film on a solid surface, that has reached a stable state where its...
• Equilibrium geometryThe molecular geometry at a minimum of the potential energy surface, where the net force on every nucleus is...
• Equilibrium melting temperatureThe theoretical melting temperature of a perfectly formed, infinitely large polymer crystal, free from...
• Equilibrium moisture contentThe moisture content of a material when it is in equilibrium with the surrounding atmosphere, meaning there...
• Equilibrium partitioningThe distribution of a chemical substance among different environmental phases or compartments, such as water...
• Equilibrium partitioning approachA methodology used to predict the concentration of a chemical in one environmental compartment based on its...
• Equilibrium reactionA reaction whose reactants start with a Boltzmann distribution of energies, so its rate constant is the...
• Equilibrium sedimentationA method for determining the molar mass and polydispersity of macromolecules in solution by subjecting them...
• Equilibrium sedimentation in a density gradientA technique where macromolecules are centrifuged in a solution containing a gradient of a dense substance...
• Equilibrium sedimentation methodA technique for determining the molar mass and molar mass distribution of macromolecules by centrifuging a...
• Equilibrium solubilityThe concentration of a solute in a solution that is saturated and in equilibrium with an excess of the solid...
• EquivalenceA state in immunology where the concentrations of antigen and antibody are optimal for the formation of...
• Equivalence postulateA working hypothesis of chain structure analysis that all monomeric units of a chain are geometrically...
• Equivalence zoneThe range of concentrations in a precipitin reaction where the ratio of antigen to antibody is optimal for...
• Equivalence-pointThe theoretical point in a titration where the amount of titrant added is stoichiometrically equivalent to...
• Equivalent chainA hypothetical model used to represent a real polymer chain for the purpose of theoretical calculations of...
• Equivalent diameterThe diameter of a hypothetical spherical particle that exhibits the same value for a specific physical...
• Equivalent freely jointed chainA theoretical model representing a real polymer chain as a series of rigid segments connected by freely...
• Equivalent hydrodynamic radiusThe radius of a hypothetical hard sphere that exhibits the same hydrodynamic behavior as a macromolecule or...
• Equivalent hydrodynamic volumeThe volume occupied by a hypothetical hard sphere that possesses the same hydrodynamic properties as a...
• Equivalent particle diameterThe diameter of a sphere that exhibits the same physical property as a non-spherical particle under specific...
• Erectile dysfunctionThe persistent inability to achieve or maintain an erection sufficient for satisfactory sexual performance...
• ErgA unit of energy in the centimeter-gram-second (CGS) system of units. It is defined as the work done by a...
• ErgotismA toxic condition caused by the ingestion of ergot alkaloids, which are produced by fungi of the genus...
• Ernst angleThe specific flip angle in a pulsed nuclear magnetic resonance experiment that provides the maximum signal...
• ErosionThe process by which a polymeric material loses mass or degrades from its surface due to chemical or physical...
• Erosion rateThe rate at which material is removed from a surface due to physical or chemical processes. This measurement...
• ErrorThe difference between a single measured result and the true or accepted value of the quantity being measured...
• Errors-in-variables regressionA statistical regression method used when both the dependent and independent variables are subject to...
• ErythemaA reddening of the skin or mucous membranes resulting from increased blood flow (hyperemia) in superficial...
• Erythro structuresA stereochemical descriptor used to denote the relative configuration of two adjacent chiral centers in an...
• Erythro, threoStereochemical prefixes used to distinguish between diastereomers that have two adjacent chiral centers. The...
• Erythroblastosis fetalisA severe hemolytic disease in a fetus or newborn infant, characterized by the destruction of red blood cells...
• ErythrocyteA red blood cell, a biconcave disc-shaped cell in the blood of vertebrates that lacks a nucleus and...
• ErythropoiesisThe physiological process of producing red blood cells (erythrocytes) in the bone marrow. This complex...
• ErythropoietinA glycoprotein hormone produced primarily by the kidneys that stimulates the production of red blood cells in...
• Escape depthThe distance perpendicular to a solid surface from which an electron or other particle has a specific...
• EscharA piece of dead tissue that has become detached from the surrounding healthy tissue, often appearing as a...
• Esin and Markov coefficientA coefficient that quantifies the dependence of the potential difference across an interface on the chemical...
• Essential nutrientA chemical substance that an organism requires for normal physiological function but cannot synthesize on its...
• EstersOrganic compounds derived from a carboxylic acid and an alcohol, formed by the removal of water. They contain...
• Estimated daily intakeThe average amount of a substance, such as a chemical or contaminant, ingested by an individual per day over...
• Estimated environmental concentrationA predicted concentration of a chemical substance in an environmental compartment, such as water, soil, or...
• Estimated exposure concentrationA calculated or modeled concentration of a substance in a specific medium to which an organism or population...
• Estimated exposure doseThe dose of a substance that an organism is likely to receive, obtained by measurement or calculation and...
• Estimated maximum daily intakeA forecast of the largest daily intake of a pesticide residue or other potentially harmful agent, computed...
• EstradiolA primary female sex hormone, belonging to the estrogen class of steroid hormones, produced mainly by the...
• EstriolA relatively weak natural estrogen and a major metabolite of estradiol and estrone, produced primarily by the...
• EstrogenA category of primary female sex hormones that are steroid compounds. These hormones are central to the...
• EstrogenicRelating to substances that mimic or modulate the actions of natural estrogens in the body. These compounds...
• Estrogen-mimeticA substance that mimics the effects of natural estrogens in the body by binding to estrogen receptors and...
• Estrous cycleThe recurring physiological and behavioral changes in most female mammals that are associated with...
• EstrusThe period of sexual receptivity in female mammals, often referred to as 'heat,' during which they are...
• Estrus syndromeA condition of persistent estrus in a female animal, caused by sustained elevated estrogenic activity from...
• EstuarineRelating to an estuary, which is a partially enclosed coastal body of water where freshwater from rivers and...
• EstuaryA partially enclosed coastal body of water where freshwater from rivers and streams mixes with saltwater from...
• EsumThe energy that must be supplied to a ground-state atom to bring it to a given excited ionic state, equal to...
• EtchTo selectively remove material from a substrate surface, typically using chemical reagents or physical...
• Etch rateThe speed at which material is removed from a substrate surface during an etching process. This rate is...
• Etiologic agentA microorganism, chemical substance, or physical factor whose presence is required for the occurrence of a...
• EtiologyThe study of the causes or origins of diseases or abnormal conditions. This field investigates the factors...
• Euatmotic reactionA reversible reaction at constant temperature in which two or more solid phases, on heating, convert entirely...
• Euclidean distanceThe ordinary straight-line separation of two points in a space of any number of dimensions. It is obtained by...
• EuglobulinA class of proteins that are insoluble in distilled water but soluble in dilute salt solutions. These...
• EukaryoteAn organism whose cells contain a nucleus enclosed within a nuclear envelope, as well as other membrane-bound...
• Euler-Lotka equationA mathematical formula used in population ecology and ecotoxicology to calculate the intrinsic rate of...
• EuphoriaA state of intense happiness, excitement, and well-being that is disproportionate to any objective cause. In...
• EuploidDescribing a cell or organism that possesses a chromosome number that is an exact multiple of the haploid...
• European Inventory of Existing Chemical SubstancesA list of chemical substances that were considered to be on the European Community market between January 1...
• Eutectic reactionAn isothermal reversible reaction in which a liquid solution transforms into two or more intimately mixed...
• Eutectoid reactionA phase transformation in which a single solid phase cools and transforms isothermally into two or more...
• EutherianRelating to placental mammals, a group characterized by the presence of a placenta that allows for a...
• Eutonic reactionA reversible dissolution process in a system with three or more components, in which the liquid phase is...
• EutrophicDescribing a body of water, such as a lake or pond, that is rich in nutrients, particularly nitrates and...
• EutrophicationThe process by which a body of water becomes progressively enriched with nutrients, primarily phosphorus and...
• EutrophyThe condition of a body of water being highly enriched with nutrients, particularly nitrogen and phosphorus...
• Evaluation dataA set of observations, also called validation data, kept for judging how well a fitted model predicts; it...
• Evaluation functionA mathematical relationship that expresses the estimated value of a measurand as a function of the observed...
• Evanescent waveA non-propagating electromagnetic field that exists near the interface of two media when light undergoes...
• Evans holeA narrow minimum within a broad infrared absorption band, such as the O-H stretching band of a...
• EvaporationThe process by which a liquid changes into a gas or vapor, typically occurring at the surface of the liquid...
• Even-electron ionAn ion containing an even number of valence electrons, where all electrons are spin-paired. These ions are...
• Even-electron ruleA principle in mass spectrometry predicting that ions with an even number of electrons, such as protonated...
• EventrationA bulging of abdominal contents, mainly the intestines, outward through a weak or defective area of the...
• EvocationInduction of one particular tissue in a developing embryo brought about by a lone chemical agent, such as a...
• Evoked potentialAn electrical potential recorded from the nervous system, typically the brain or spinal cord, in response to...
• Evoked responseA measurable electrical or physiological change in a biological system that occurs consistently in response...
• EvolutionThe process of change in the inherited traits of a population of organisms across successive generations...
• Evolved gas analysisA thermal analysis technique that involves monitoring the gases released from a sample as it is heated or...
• Evolved gas detectionThe process of identifying and quantifying the gaseous products released from a sample during a thermal...
• ExaA prefix used in the International System of Units (SI) to denote a factor of 10^18. This prefix is applied...
• Exact massThe mass of an ion calculated using the exact masses of its constituent isotopes, rather than the average...
• ExaminandThe nominal property that an examination sets out to determine, the counterpart of the measurand for...
• ExaminationA set of operations carried out to determine the value of a nominal property of an examinand. This process...
• Examination accuracyHow near an examined value of a nominal property lies to the true value of that property for the examinand...
• Examination biasThe systematic difference between the average of a large number of examination results and a true value of...
• Examination calibrationThe set of operations that establish the relationship between the values indicated by a measuring system and...
• Examination calibratorA substance, material, or device with one or more known property values that is used to calibrate an...
• Examination errorThe discrepancy between an examined value and the corresponding true value of a nominal property. This type...
• Examination methodA detailed written description of the logical sequence of operations used to perform an examination of a...
• Examination precisionThe closeness of agreement between independent examined values obtained under specified conditions for a...
• Examination principleThe fundamental scientific law or phenomenon upon which an examination method is based for determining a...
• Examination procedureA detailed set of instructions for carrying out a specific examination method, often tailored for a...
• Examination repeatabilityThe precision of an examination under repeatability conditions, where independent examined values are...
• Examination reproducibilityThe precision of an examination under reproducibility conditions, where independent examined values are...
• Examination resultThe value of a nominal property obtained by performing an examination. This result is expressed as a word...
• Examination standardA material or object embodying the definition of a particular nominal property, with a stated nominal...
• Examination traceabilityThe property of a result by which it is linked to a stated reference, such as an SI unit or a reference...
• Examination truenessA measure of accuracy for nominal (qualitative) examinations, representing the proportion of examined values...
• Examination uncertaintyThe share of examined values that disagree with a reference nominal property value, out of all the examined...
• Examinational compatibilityA relation among several examination results for the same examinand and kind of nominal property whose...
• Examined valueA value of a nominal property obtained through an examination process in a clinical laboratory setting...
• Examining systemThe complete set of procedures, equipment, and materials used to perform a specific type of examination in a...
• Excess lifetime riskThe additional probability of an individual developing a specific adverse health effect over their lifetime...
• Excess Rayleigh ratioThe difference between the Rayleigh ratio of a polymer solution and that of the pure solvent, representing...
• Excess scatteringThe portion of scattered light intensity from a polymer solution that is attributable solely to the presence...
• Excess volumeThe difference between the actual volume of a mixture and the sum of the volumes of its pure components...
• Exchange currentThe rate of electron transfer between an electrode and an electrolyte at equilibrium, where the net current...
• Exchange diffusionA type of facilitated diffusion where the movement of one solute across a membrane is coupled to the movement...
• Exchange extractionA type of liquid-liquid extraction where an ion in one phase is exchanged for another ion of the same charge...
• Exchange labellingA method of introducing a radioactive or stable isotope into a molecule by exchanging an atom or group of...
• Exchange repulsionA quantum mechanical effect arising from the Pauli exclusion principle, which prevents electrons with the...
• Exchange spectroscopyA two-dimensional nuclear magnetic resonance (NMR) experiment designed to detect chemical or conformational...
• Exchange transfusionA medical procedure involving the removal of a patient's blood and its replacement with donor blood. This...
• Exchange-inversion transitionA first-order phase transition in a solid where the sign of the magnetic exchange interaction between...
• ExcimerA transient dimeric species formed between an excited state molecule and a ground state molecule of the same...
• Excimer lampA gas discharge lamp that produces incoherent ultraviolet or vacuum ultraviolet radiation through the...
• Excimer laserA type of gas laser that generates coherent ultraviolet light by stimulating the emission from an excimer...
• Excimer-luminescenceThe emission of light from an excimer, which is an excited dimer formed between two identical molecules, one...
• ExcipientAn inactive substance formulated alongside the active pharmaceutical ingredient in a medicinal product. It...
• ExciplexA transient excited-state complex formed between an excited state molecule and a ground state molecule of a...
• Excitable cellA cell capable of generating and propagating electrical signals, known as action potentials, in response to...
• ExcitationThe process of raising an atom, molecule, or ion from its ground electronic state to a higher energy state by...
• Excitation energyThe minimum amount of energy required to promote an atom, molecule, or ion from its ground electronic state...
• Excitation levelA specific quantized energy state of an atom, molecule, or ion that is higher in energy than its ground...
• Excitation profileA plot showing the intensity of a specific Raman scattering band as a function of the excitation laser's...
• Excitation sculptingA nuclear magnetic resonance (NMR) technique that uses pulsed field gradients to selectively excite or...
• Excitation spectrumA plot of the intensity of emitted light (fluorescence or phosphorescence) as a function of the excitation...
• Excitation transferThe process by which electronic excitation energy is transferred from one molecule or chromophore to another...
• Excitation-emission spectrumA three-dimensional plot or contour map that displays the fluorescence emission intensity as a function of...
• Excitatory post-synaptic potentialA temporary depolarization of the post-synaptic membrane caused by the flow of positively charged ions into...
• Excited stateA state of a quantum mechanical system, such as an atom or molecule, that possesses more energy than its...
• ExcitonA mobile, electrically neutral quasiparticle representing an excited state in a semiconductor or insulator...
• Exciton absorptionThe process where a photon is absorbed by a material, leading to the creation of an exciton, which is a bound...
• Exciton annihilationA process in which two excitons interact, leading to the de-excitation of one exciton and the transfer of its...
• Exciton diffusionThe movement of an exciton, a bound state of an electron and an electron hole, through a material from its...
• Exciton dissociationThe process where a bound electron-hole pair (exciton) separates into a free electron and a free hole, which...
• Exciton mean free pathThe average distance an exciton travels in a material before undergoing a scattering event or recombination...
• Exciton-phonon couplingThe interaction between an exciton and a phonon, which is a quantum of lattice vibration. This coupling...
• ExcitotoxicityThe pathological process by which nerve cells are damaged and killed by excessive stimulation from excitatory...
• Excluded volume of a macromoleculeThe effective volume from which a macromolecule in dilute solution keeps other macromolecules out. It is set...
• Excluded volume of a segmentThe effective volume from which one chain segment keeps all other segments out, whether they belong to the...
• Exclusion chromatographyA chromatographic technique that separates molecules based primarily on their size and shape. Molecules are...
• ExcretionThe irreversible removal of a substance or its metabolites from a biological system, typically through...
• Excretion rateThe amount of a chemical or its metabolites eliminated from the body per unit of time. This measurement is a...
• ExcurrentRelating to the ducts or passages through which a substance, such as a glandular secretion or waste product...
• ExencephalyA severe congenital malformation characterized by the brain being located outside the skull, typically...
• Exergonic reactionA chemical reaction characterized by a negative overall standard Gibbs free energy change (ΔG° < 0). Such a...
• Exfoliated graphiteA form of graphite produced by the rapid expansion of graphite intercalation compounds, typically through...
• ExfoliationThe process of separating individual layers from a layered material, such as a clay mineral or graphite, to...
• Exhaustive extractionA process designed to remove essentially all of an analyte or group of analytes from a sample matrix. This...
• Exit channelA specific pathway on a potential-energy surface that leads from the transition state of a chemical reaction...
• ExoconThe part of a conjugated metabolite that originates from the parent molecule, that is, from the foreign...
• ExocrineRelating to glands that secrete their products into ducts, which then carry the secretions to an external...
• ExocytosisA cellular process in which substances are transported from the interior of the cell to the exterior by...
• ExoenzymesEnzymes that remove monomers, or occasionally dimers or oligomers, one after another from an end of a polymer...
• ExogenousOriginating from outside an organism, system, or cell. In toxicology, it describes a substance, such as a...
• Exogenous deoxyribonucleic acidA deoxyribonucleic acid (DNA) molecule that originates from outside the organism, cell, or system being...
• ExometabolomeThe complete set of metabolites secreted or released by a cell, tissue, or organism into its external...
• ExomphalosA congenital birth defect where some or all of the abdominal organs protrude through an opening in the...
• ExonA segment of a eukaryotic gene that codes for a portion of the final messenger RNA (mRNA) molecule and is...
• ExonucleaseAn enzyme that catalyzes the sequential cleavage of individual nucleotides from a free terminus of a...
• ExophthalmiaAn abnormal protrusion or bulging of one or both eyeballs from the orbit, also known as proptosis. This...
• ExotheliumA sheet of flattened epithelial cells lying outside an organ or tissue. The name contrasts with endothelium...
• Exothermic reactionA chemical reaction that releases thermal energy (heat) to its surroundings, resulting in a negative change...
• ExotoxinA toxic substance secreted by bacteria into their surroundings, capable of causing damage to host cells or...
• Expansion factorA dimensionless ratio comparing the size of a polymer coil in a particular solvent with its size in the theta...
• Expected environmental concentrationA predicted concentration of a chemical substance in a specific environmental compartment, such as water...
• Expected life spanThe average period that an organism or a population of organisms is anticipated to live under specific...
• Experimental absorbanceThe decadic absorbance as measured, without correction for losses other than absorption, so reflection at...
• Experimental designThe structured plan for conducting an experiment to collect data that can be analyzed to draw valid...
• Experimental ecosystemA controlled and simplified ecological system created in a laboratory or field setting to study ecological...
• Experimental perturbational calculationA computational check on a least-squares fit in which the calculation is repeated many times with the input...
• Experimental scattered-ion intensityThe measured signal strength of ions that have been scattered from a sample surface during an ion scattering...
• Expert systemA computer program that emulates the problem-solving and reasoning capabilities of a specialist within a...
• Explanatory variableA variable in a statistical model that is hypothesized to influence or explain changes in a response...
• ExplantA piece of tissue or an organ removed from a living organism and transferred to an artificial medium for in...
• Explicit solventA computational model where individual solvent molecules are represented with their atomic coordinates and...
• Exploitation competitionAn indirect form of competition between organisms or species where individuals consume a shared, limited...
• Exploratory data analysisAn approach to data analysis that emphasizes graphical representation and data visualization to reveal...
• Explosivity limitsThe range of concentrations of a flammable gas or vapor in air, between which an explosion can occur when an...
• Exponential decayThe decrease in a quantity where the rate of decrease is directly proportional to the current value of the...
• Exponential growthA pattern of increase in which the rate of growth of a quantity is directly proportional to its current...
• ExposedRelating to an organism, population, or ecosystem that has been subjected to contact with a chemical...
• Exposed groupA cohort of individuals in an epidemiological study who have experienced contact with a specific agent or...
• ExposureThe contact of an organism with a chemical, physical, or biological agent, quantified by the amount of the...
• Exposure assessmentThe process of measuring or estimating the magnitude, frequency, and duration of human or ecological contact...
• Exposure characterisationThe qualitative and quantitative description of the nature and extent of exposure to a contaminant. This...
• Exposure latitudeThe range of exposure doses over which a photoresist can be processed to yield a feature size that remains...
• Exposure limitA maximum permissible concentration of a chemical or physical agent in the environment or workplace that is...
• Exposure pathwayThe course a chemical agent takes from its source to an organism that results in contact. A complete pathway...
• Exposure profileA representation of the concentration of a substance in a specific environmental medium or organism as a...
• Exposure ratioA measure of the relative likelihood of exposure to a particular agent in a case-control study. It compares...
• Exposure scenarioA set of conditions and assumptions describing how a substance is manufactured, used, or disposed of, and how...
• Exposure surfaceThe area of an organism's body that is directly in contact with an external chemical agent or environmental...
• Exposure testBiological monitoring in which the amount of a potentially toxic compound, or of its metabolites, taken up by...
• Expressed sequence tagA short, single-pass sequence of complementary DNA (cDNA) that represents a portion of an expressed gene...
• ExpressionThe process by which information from a gene is used in the synthesis of a functional gene product, such as a...
• Expression proteomicsThe large-scale study of protein expression levels within a biological system under specific conditions. This...
• ExstrophyA congenital malformation characterized by the eversion or turning inside out of an organ, particularly the...
• Extended connectivity fingerprintsA type of molecular descriptor used in cheminformatics that encodes structural information about a molecule...
• Extended Hammett equationA modification of the original Hammett equation that incorporates additional substituent parameters to...
• Extended Hückel MO methodA semi-empirical quantum mechanical method used to calculate molecular orbital energies and wavefunctions for...
• Extended X-ray absorption fine structureThe oscillatory part of the X-ray absorption coefficient spectrum above the absorption edge, extending to...
• Extended X-ray absorption fine structure spectroscopyA technique that analyzes the fine structure oscillations in the X-ray absorption coefficient at energies...
• Extended-chain crystalA crystal of a polymer whose chains are stretched out almost completely, running straight through the crystal...
• ExtenderA substance added to a polymer formulation to reduce its cost, improve certain properties, or increase its...
• Extensive quantityA physical quantity whose value is proportional to the amount of substance or the size of the system. If a...
• ExtentA surface quantity measured by its area, with the real area of a rough solid distinguished from the geometric...
• Extent of electron delocalizationA qualitative or quantitative description of the spatial spread of electron density over multiple atoms...
• Extent of reactionA quantity that measures how far a chemical reaction has advanced, defined by the change dxi = dn(i) / nu(i)...
• External calibrationA calibration method in which the analytical instrument is standardized using a series of known...
• External fieldA physical field, such as an electric, magnetic, or flow field, applied to a system from outside its...
• External genitaliaThe reproductive organs that are visible on the outside of the body. In male mammals, these structures...
• External quantum efficiencyThe ratio of the number of photons emitted from a device to the number of charge carriers (electrons or...
• External quantum yieldThe ratio of the number of photons emitted from an optoelectronic device to the number of charge carriers...
• External reflection spectroscopyA spectroscopic method where radiation is directed onto the surface of a sample at an angle, and the...
• External standardA reference substance of known concentration that is analyzed separately from the sample to create a...
• External standardization for quenching correctionA liquid scintillation counting method for correcting quenching in which a gamma-emitting source is brought...
• External surfaceThe accessible surface area of a porous material that is not part of its internal pore structure. This...
• External validityThe extent to which the findings of a scientific study can be generalized to other populations, settings, or...
• ExterplexA termolecular excited-state complex, the three-component analogue of an exciplex, that is non-bonding in its...
• Extinction probabilityThe likelihood that a population of organisms will eventually die out completely. This probability is...
• Extra riskThe probability that an exposure produces a response, corrected for the background response that occurs...
• Extracellular matrixA complex network of macromolecules, such as collagen, elastin, and glycoproteins, that is secreted by cells...
• Extracellular spaceThe volume within a tissue that lies outside its cells, not counting the vascular and lymphatic spaces, so...
• Extracellular volumeThe total volume of fluid in a body that exists outside of the cells, comprising both the plasma and the...
• ExtractA solution or mixture obtained by treating a substance with a solvent to selectively dissolve certain...
• ExtractabilityA qualitative property indicating how readily, or to what degree, a substance is extracted from one phase...
• ExtractantThe principal active component of an extraction system, which is chiefly responsible for moving the solute...
• Extracted ion chromatogramA chromatogram obtained by plotting the abundance of one or more specific ions, or a narrow range of m/z...
• Extracted ion electropherogramA plot of the intensity of a specific mass-to-charge ratio (m/z) ion as a function of migration time in a...
• Extracted ion profileA plot of the intensity of a specific mass-to-charge ratio (m/z) ion as a function of time or scan number...
• ExtractionA separation technique that selectively transfers one or more components from a solid or liquid mixture into...
• Extraction constantThe equilibrium constant of the overall extraction reaction, for example a metal ion in water reacting with...
• Extraction factorA dimensionless quantity that represents the ratio of the amount of solute extracted into the extracting...
• Extraction fieldAn electric field applied in mass spectrometry to accelerate ions from the ion source into the mass analyzer...
• Extraction fractionationA method used to separate a polymer sample into fractions based on differences in molecular weight or...
• Extraction phaseThe liquid, solid or gas phase placed in contact with a sample so that analytes are transferred from the...
• Extraction rateThe speed at which a substance is transferred from one phase to another during an extraction process. This...
• Extraction ratioThe fraction of a substance that is removed from the blood as it passes through an organ, typically the liver...
• Extractive distillationA distillation technique used to separate components of a liquid mixture that have close boiling points or...
• Extractive electrospray ionization mass spectrometryA direct-analysis technique in which an inert gas carries molecules or aerosol from a sample in air into a...
• Extractor voltageThe electrical potential applied to an electrode, known as an extractor, in an ion source or mass...
• Extraembryonic membraneSpecialized tissues that develop from the zygote but are not part of the embryo itself, providing support...
• Extraembryonic mesodermA layer of cells that forms during early embryogenesis, located between the inner surface of the trophoblast...
• Extraneous residue limitA Codex Alimentarius recommended ceiling for a pesticide residue or other contaminant found in a food, farm...
• Extraordinary waveA wave of electromagnetic radiation that propagates through an anisotropic medium, such as a birefringent...
• Extrapolated rangeThe distance in a material that an ionizing particle, such as an alpha or beta particle, appears to travel...
• ExtrapolationThe process of estimating values or effects beyond the range of observed data, often from high-dose animal...
• Extrapolation factorA numerical factor used in risk assessment to account for uncertainties when extrapolating toxicity data from...
• Extrapyramidal movement disordersA group of neurological conditions characterized by involuntary movements or impaired voluntary movements...
• ExtravasationThe movement of cells, particularly leukocytes, or fluids from the interior of a blood or lymphatic vessel...
• Extreme ultraviolet lithographyA next-generation photolithography technique that uses extreme ultraviolet (EUV) radiation, typically at a...
• ExtremophilesMicroorganisms that thrive in environments considered extreme or hostile to most life forms, such as very...
• Extrinsic absorptionLight absorption in a material that arises from impurities, defects, or dopants within its structure, rather...
• Extrinsic defectA type of crystal lattice imperfection caused by the presence of impurity atoms within the material. These...
• Extrinsic pathwayThe apoptotic pathway of cell death that starts when ligands such as Fas ligand or tumour necrosis factor...
• Extrinsic plasmonA plasmon, a quantized collective oscillation of the valence electrons, that is excited by an electron as it...
• Extrinsic semiconductorA semiconductor material whose electrical conductivity is significantly enhanced by the controlled addition...
• Extrusion transformationA chemical transformation in which an atom or group, originally bonded to two other atoms within a molecule...
• ExudateA fluid, rich in protein and cellular debris, that leaks out of blood vessels into tissues or onto surfaces...
• E/Z photoisomerizationA photochemical process involving the interconversion between the E (entgegen) and Z (zusammen) stereoisomers...

816 of 13,676 terms in Chemistry terminology (MLC-0109). Request the full dataset.