Selective catalytic reductionSelective catalytic reduction (SCR) means of converting nitrogen oxides, also referred to as NOxNOx with the aid of a catalyst into diatomic nitrogen (N2), and water (H2O). A reductant, typically anhydrous ammonia (NH3), aqueous ammonia (NH4OH), or a urea (CO(NH2)2) solution, is added to a stream of flue or exhaust gas and is reacted onto a catalyst. As the reaction drives toward completion, nitrogen (N2), and carbon dioxide (CO2), in the case of urea use, are produced.
Synthetic geometrySynthetic geometry (sometimes referred to as axiomatic geometry or even pure geometry) is geometry without the use of coordinates. It relies on the axiomatic method for proving all results from a few basic properties initially called postulate, and at present called axioms. The term "synthetic geometry" has been coined only after the 17th century, and the introduction by René Descartes of the coordinate method, which was called analytic geometry.
Transformation geometryIn mathematics, transformation geometry (or transformational geometry) is the name of a mathematical and pedagogic take on the study of geometry by focusing on groups of geometric transformations, and properties that are invariant under them. It is opposed to the classical synthetic geometry approach of Euclidean geometry, that focuses on proving theorems. For example, within transformation geometry, the properties of an isosceles triangle are deduced from the fact that it is mapped to itself by a reflection about a certain line.
Synthetic biologySynthetic biology (SynBio) is a multidisciplinary field of science that focuses on living systems and organisms, and it applies engineering principles to develop new biological parts, devices, and systems or to redesign existing systems found in nature. It is a branch of science that encompasses a broad range of methodologies from various disciplines, such as biotechnology, biomaterials, material science/engineering, genetic engineering, molecular biology, molecular engineering, systems biology, membrane science, biophysics, chemical and biological engineering, electrical and computer engineering, control engineering and evolutionary biology.
Copper in architectureCopper has earned a respected place in the related fields of architecture, building construction, and interior design. From cathedrals to castles and from homes to offices, copper is used for a variety of architectural elements, including roofs, flashings, gutters, downspouts, domes, spires, vaults, wall cladding, and building expansion joints. The history of copper in architecture can be linked to its durability, corrosion resistance, prestigious appearance, and ability to form complex shapes.
DepressantDepressants, or central depressants, are drugs that lower neurotransmission levels, or depress or reduce arousal or stimulation in various areas of the brain. Depressants are also colloquially referred to as "downers" as they lower the level of arousal when taken. Depressants do not change the mood or mental state of others. Stimulants, or "uppers," increase mental or physical function, hence the opposite drug class from depressants are stimulants, not antidepressants.
HomographyIn projective geometry, a homography is an isomorphism of projective spaces, induced by an isomorphism of the vector spaces from which the projective spaces derive. It is a bijection that maps lines to lines, and thus a collineation. In general, some collineations are not homographies, but the fundamental theorem of projective geometry asserts that is not so in the case of real projective spaces of dimension at least two. Synonyms include projectivity, projective transformation, and projective collineation.
AntidepressantAntidepressants are a class of medications used to treat major depressive disorder, anxiety disorders, chronic pain, and addiction. Common side effects of antidepressants include dry mouth, weight gain, dizziness, headaches, sexual dysfunction, and emotional blunting. There is an increased risk of suicidal thinking and behavior when taken by children, adolescents, and young adults. Discontinuation syndrome, which resembles recurrent depression in the case of the SSRI class, may occur after stopping the intake of any antidepressant, the effects of which may be permanent and irreversible.
Self-medicationSelf-medication is a human behavior in which an individual uses a substance or any exogenous influence to self-administer treatment for physical or psychological conditions: for example headaches or fatigue. The substances most widely used in self-medication are over-the-counter drugs and dietary supplements, which are used to treat common health issues at home. These do not require a doctor's prescription to obtain and, in some countries, are available in supermarkets and convenience stores.
Artificial gene synthesisArtificial gene synthesis, or simply gene synthesis, refers to a group of methods that are used in synthetic biology to construct and assemble genes from nucleotides de novo. Unlike DNA synthesis in living cells, artificial gene synthesis does not require template DNA, allowing virtually any DNA sequence to be synthesized in the laboratory. It comprises two main steps, the first of which is solid-phase DNA synthesis, sometimes known as DNA printing. This produces oligonucleotide fragments that are generally under 200 base pairs.
