42,772 articles
Enzymatic recycling of polyethylene terephthalate
Enzymatic recycling of polyethylene terephthalate (PET) is a chemical recycling method in which enzymes break PET plastic into its monomers at mild temperatures, with the first commercial plant planned in France by Carbios.
Enzymatic ring-opening polymerization
Enzymatic ring-opening polymerization, or eROP, is a polymerization method in which a lipase enzyme, usually Candida antarctica lipase B, builds biodegradable polyesters from cyclic monomers under mild, metal-free conditions.
Enzyme electrode
An enzyme electrode is an electrochemical sensor in which an immobilized enzyme layer on an electrode lets reaction products be measured, the core of biosensors like blood glucose meters.
Enzyme-assisted extraction
Enzyme-assisted extraction (EAE) is a green extraction method that uses hydrolytic enzymes such as cellulases and pectinases to degrade plant cell walls, improving yields of bioactive compounds.
Eoarchean
The Eoarchean is the earliest era of the Archean eon, spanning 4031 to 3600 million years ago, containing Earth's oldest dated rocks and oldest contested evidence for life.
Eocene
The Eocene is a geologic epoch from 56 to 33.9 million years ago, the second epoch of the Paleogene Period and the longest warm interval of the Cenozoic.
Eosin
Eosin is a family of red xanthene dyes derived from fluorescein, best known as the pink counterstain in H&E histology, named for the Greek goddess of dawn.
Eosin Y organophotoredox catalysis
Eosin Y organophotoredox catalysis is the use of the organic dye eosin Y as a cheap, metal-free photocatalyst that absorbs visible light to drive organic reactions.
Eötvös experiment
The Eötvös experiment is a class of physics tests, first performed by Loránd Eötvös with a torsion balance from 1888, comparing the gravitational and inertial mass of different materials.
EPA Greenhouse Gas Reporting Program
The EPA Greenhouse Gas Reporting Program is a mandatory US system under which large emitters and fossil fuel suppliers report greenhouse gas data annually, established in 2009.
Epact
An epact is the age of the Moon in days on the first day of the calendar year, used since antiquity to calculate the date of Easter.
EPDM rubber
EPDM rubber (ethylene propylene diene monomer) is a widely used synthetic rubber of ethylene, propylene, and a small diene fraction, known for heat, ozone, and weather resistance in roofing, weatherstripping, and hoses.
EPED model
The EPED pedestal model, developed by Philip B. Snyder and colleagues at General Atomics, predicts the height and width of the H-mode pedestal in tokamak plasmas.
Ephedrine
Ephedrine, from Ephedra sinica (ma huang, Mahuang), is a sympathomimetic plant alkaloid isolated by Nagai in 1885, rediscovered by Chen and Schmidt, once a leading oral asthma drug, now restricted as a methamphetamine precursor.
Ephemeris
An ephemeris (plural: ephemerides), also called astronomical tables, is a table of computed positions and velocities of an orbiting body, such as a planet, asteroid, or spacecraft, at specific times.
Ephemeris time
Ephemeris time was a theoretically uniform time scale adopted by the International Astronomical Union in 1952; its ephemeris second was the SI second from 1960 until atomic time replaced it.
Epicatechin
Epicatechin is a flavan-3-ol (catechin) plant polyphenol, C₁₅H₁₄O₆, the most abundant monomeric flavan-3-ol in cocoa, abundant also in tea, and a likely candidate behind cocoa's cardiovascular effects.
Epicenter
The epicenter, also spelled epicentre, is the point on the Earth's surface directly above the hypocenter, where an earthquake's rupture begins at depth. It is located by triangulation among seismographs.
Epichlorohydrin
Epichlorohydrin, also called glycidyl chloride or chloropropylene oxide, is a colorless, flammable epoxide liquid used chiefly to make epoxy resins and synthetic glycerine, and classified as a probable human carcinogen.
Epigallocatechin
Epigallocatechin (EGC) is a flavan-3-ol catechin polyphenol with six hydroxyl groups and the formula C15H14O7, the second predominant catechin in green tea, first isolated in 1948.
Epikarst
Epikarst is the uppermost, intensely weathered zone of karstified carbonate rock, also called the subcutaneous zone, acting as a perched aquifer that stores rainwater and regulates recharge to deeper karst.
Epilimnion
The epilimnion is the warm, well-mixed upper layer of a stratified lake, holding the warmest water and mixed by wind, typically 10 to 40 feet thick.
Epilithon
Epilithon is the community of algae, bacteria, fungi, and protozoa that grows attached to rocks and stones in streams and lakes, forming the familiar slimy biofilm.
Epimenides paradox
The Epimenides paradox, also called the Cretan paradox, is a self-reference puzzle from the saying "all Cretans are liars" by Epimenides of Crete, quoted at Titus 1:12.
Epimer
An epimer is one of a pair of diastereomers that differ in configuration at only one of two or more stereogenic centers, like D-galactose versus D-glucose.
Epimetheus (moon)
Epimetheus is a small, cratered moon of Saturn, about 116 km across, that shares its orbit with Janus; the two swap places roughly every four years.
Epiphenomenalism
Epiphenomenalism, also called Type-E dualism, is a position in philosophy of mind holding that brain processes cause conscious mental states, which are real but causally inert.
Epirubicin
Epirubicin, also known as 4′-epidoxorubicin and marketed in the United States as Ellence, is an anthracycline chemotherapy drug, an isomer of doxorubicin, used mainly to treat breast cancer.
Episodic accretion
Episodic accretion is the growth of a forming star through short, intense accretion bursts from its circumstellar disk, separated by long quiet intervals, as seen in the FU Orionis objects.
Epistemic cultures
Epistemic cultures are the distinct arrangements and mechanisms by which an expert community creates and warrants knowledge, a concept introduced in 1999 by the sociologist Karin Knorr Cetina.