All articles starting with D
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Directed C–H functionalization
Directed C–H activation is a synthesis strategy in which a directing group on a substrate guides a metal catalyst to one specific carbon–hydrogen bond for selective functionalization.
Directed C–H trifluoromethylation
Directed C–H trifluoromethylation is the site-selective replacement of a carbon–hydrogen bond with a trifluoromethyl group, where a directing group positions a metal catalyst, such as palladium, at a chosen site.
Directed content analysis
Directed content analysis is a deductive qualitative research method that applies theory-derived coding categories to text to validate or extend the theory, one of three content analysis approaches.
Directed differentiation
Directed differentiation guides pluripotent stem cells (ESCs, iPSCs) through sequential cell-fate decisions using growth factors, small molecules, and morphogens to yield desired cell types for disease models, drug screening, organoids, and transplantation therapies.
Directed energy deposition
Directed energy deposition (DED) is a metal additive manufacturing process in which a laser, electron beam, or arc melts powder or wire as it is deposited.
Directed evolution
Directed evolution, also called directed protein evolution, is a protein engineering method that iteratively introduces mutations and selects improved variants, pioneered by Frances Arnold, who won the 2018 Nobel Prize in Chemistry.
Directed evolution of artificial metalloenzymes for abiological reactions
Directed evolution of artificial metalloenzymes optimizes by mutagenesis and screening hybrid catalysts that combine a synthetic metal cofactor with a protein scaffold to catalyze abiological reactions.
Directed evolution of carbene transferases
Directed evolution of carbene transferases is the laboratory practice of improving engineered heme proteins that catalyze carbene transfer reactions, a field begun at Caltech in 2013.
Directed evolution of cytochrome P450 for C–H amination
Directed evolution of cytochrome P450 for C–H amination turns P450 enzymes into catalysts that insert nitrogen into carbon–hydrogen bonds, first reported by the Arnold group in 2013.
Directed evolution of enzymes for the Diels–Alder reaction
Directed evolution of enzymes for the Diels–Alder reaction iteratively mutagenizes and screens proteins to create biocatalysts for the [4+2] cycloaddition of a diene and dienophile to a cyclohexene product.
Directed evolution of P411 carbene transferases
Directed evolution of P411 carbene transferases optimizes serine-ligated cytochrome P411 enzymes, begun in 2013 in Frances Arnold's group at Caltech, to catalyze non-natural carbene transfer reactions.
Directed graph
A directed graph, or digraph, is a graph whose edges are ordered pairs of vertices, drawn as arrows followed in one direction, modeling one-way streets, social networks, and dependencies.
Directed ortho metalation
Directed ortho metalation, also called ortho-lithiation, is an organic chemistry strategy in which a directing substituent guides strong bases to metalate the ortho position of aromatic rings regioselectively.
Directed percolation
Directed percolation is a nonequilibrium stochastic process in which activity spreads along a preferred direction, usually time, and it defines the principal universality class of continuous transitions into absorbing states.
Directed percolation transition in turbulence
The directed percolation transition in turbulence describes the onset of turbulence in shear flows as a non-equilibrium phase transition in the directed percolation class, proposed by Y. Pomeau in 1986.
Directed self-assembly
Directed self-assembly (DSA) is a nanofabrication technique in which block copolymers amplify lithographic guide patterns into finer nanostructures, used as a resolution-enhancement step in semiconductor patterning.
Directed-energy weapon
A directed-energy weapon (DEW) is a weapon using concentrated electromagnetic energy instead of kinetic energy to destroy targets. Types include high-energy lasers and high-power microwave weapons, first fielded by the US Navy in 2014.
Directia 5
Direcția 5 is a Romanian pop-rock band founded in 1991 in Bucharest by Marian Ionescu, one of Romania's best-known bands, famous for the 1993 hit "Seducție".
Directing Council of Transylvania
The Directing Council of Transylvania (Consiliul Dirigent al Transilvaniei) was the provisional government of Transylvania from 1918 to 1920, seated at Sibiu under President Iuliu Maniu.
DirectInput
DirectInput, also known as DInput, is a Microsoft DirectX API for reading input from the mouse, keyboard, joysticks, and force-feedback devices, built for Windows games and simulations.
Direction – Social Democracy
Direction – Social Democracy (Smer-SD) is Slovakia's principal social democratic party, led by Robert Fico. It returned to government in 2023, adopted conservative-national positions, and was expelled from the Party of European Socialists in October 2025.
Direction (geometry)
Direction, also called spatial direction or the direction of a line, is which way a line, ray, or displacement points, independent of position and often of length.
Direction cosines
Direction cosines are the cosines of the angles a directed line or vector in 3D space makes with the positive coordinate axes, equal to the components of the unit vector along it.
Direction finding
Direction finding (DF), also called radio direction finding or DFing, measures the bearing of an arriving radio signal; intersecting bearings from two or more stations locate a transmitter.
Direction générale de l'armement
The Direction générale de l'armement (DGA, Directorate General for Armament) is the French defense procurement agency, created by Charles de Gaulle in 1961 to equip the French armed forces.
Direction générale de l'Aviation civile
The Direction générale de l'Aviation civile (DGAC) is the French state administration responsible for civil aviation safety, air traffic management, and market regulation, created by decree in 1976.
Direction of arrival estimation
Direction of arrival (DOA) estimation determines the directions from which radio or acoustic signals arrive at a sensor array, underpinning radar, sonar, and wireless beamforming.
Directional array
A directional array combines the signals of two or more antenna elements with controlled amplitudes and phases to concentrate energy in some directions and suppress it in others.
Directional boring
Directional boring, also called horizontal directional drilling (HDD), is a trenchless method for installing underground pipes, conduits, and cables, used beneath rivers, roads, and railroads.
Directional dark matter detectors
A directional dark matter detector reconstructs the direction of nuclear recoils from galactic dark matter, typically using a low-pressure gaseous time projection chamber that images recoil tracks.