The moment of inertia, otherwise known as the angular mass or rotational inertia, of a rigid body is a quantity that determines the torque needed for a desired angular acceleration about a rotational axis; similar to how mass determines the force needed for a desired acceleration. It depends on the body's mass distribution and the axis chosen, with larger moments requiring more torque to change the body's rotation rate. It is an extensive (additive) property: for a point mass the moment of inertia is just the mass times the square of the perpendicular distance to the rotation axis. The moment of inertia of a rigid composite system is the sum of the moments of inertia of its component subsystems. Its simplest definition is the second moment of mass with respect to distance from an axis. For bodies constrained to rotate in a plane, only their moment of inertia about an axis perpendicular to the plane, a scalar value, matters. For bodies free to rotate in three dimensions, their moments can be described by a symmetric 3 × 3 matrix, with a set of mutually perpendicular principal axes for which this matrix is diagonal and torques around the axes act independently of each other.
Isobaric process is a thermodynamic process in which the pressure stays constant: ΔP = 0. The heat transferred to the system does work, but also changes the internal energy of the system. This article uses the physics sign convention for work, where positive work is work done by the system. Using this convention, by the first law of thermodynamics,
Ergoline derivatives comprise a diverse group of chemical compounds whose structural skeleton is the alkaloid ergoline. Ergoline derivatives are used clinically for the purpose of vasoconstriction (5-HT1 receptor agonists—ergotamine) and in the treatment and alleviation of migraines (used with caffeine) and Parkinson's disease. Some ergoline alkaloids found in ergot fungi are implicated in the condition ergotism, which causes convulsive and gangrenous symptoms. Others are psychedelic substances, including LSD and some alkaloids in Argyreia nervosa, Ipomoea tricolor and related species.
Lovastatin, sold under the brand name Mevacor among others, is a statin medication, to treat high blood cholesterol and reduce the risk of cardiovascular disease. It use is recommended together with lifestyle changes. It is taken by mouth.
In theoretical physics, the hierarchy problem is the large discrepancy between aspects of the weak force and gravity. There is no scientific consensus on why, for example, the weak force is 1024 times stronger than gravity.
The Tsiolkovsky rocket equation, classical rocket equation, or ideal rocket equation is a mathematical equation that describes the motion of vehicles that follow the basic principle of a rocket: a device that can apply acceleration to itself using thrust by expelling part of its mass with high velocity can thereby move due to the conservation of momentum.
Equivalent airspeed (EAS) is calibrated airspeed (CAS) corrected for the compressibility of air at a non-trivial Mach number. It is also the airspeed at sea level in the International Standard Atmosphere at which the dynamic pressure is the same as the dynamic pressure at the true airspeed (TAS) and altitude at which the aircraft is flying. In low-speed flight, it is the speed which would be shown by an airspeed indicator with zero error. It is useful for predicting aircraft handling, aerodynamic loads, stalling etc.
The Compton wavelength is a quantum mechanical property of a particle. It was introduced by Arthur Compton in his explanation of the scattering of photons by electrons. The Compton wavelength of a particle is equal to the wavelength of a photon whose energy is the same as the mass of that particle.
Beta Cassiopeiae, officially named Caph, is a Delta Scuti variable star in the constellation of Cassiopeia. It is a giant star belonging to the spectral class F2. The white star of second magnitude has an absolute magnitude of +1.16 mag.
Smith–Lemli–Opitz syndrome is an inborn error of cholesterol synthesis. It is an autosomal recessive, multiple malformation syndrome caused by a mutation in the enzyme 7-Dehydrocholesterol reductase encoded by the DHCR7 gene. It causes a broad spectrum of effects, ranging from mild intellectual disability and behavioural problems to lethal malformations.
Pregnenolone (P5), or pregn-5-en-3β-ol-20-one, is an endogenous steroid and precursor/metabolic intermediate in the biosynthesis of most of the steroid hormones, including the progestogens, androgens, estrogens, glucocorticoids, and mineralocorticoids. In addition, pregnenolone is biologically active in its own right, acting as a neurosteroid.
β-Sitosterol (beta-sitosterol) is one of several phytosterols with chemical structures similar to that of cholesterol. It is a white, waxy powder with a characteristic odor, and is one of the components of E499. Phytosterols are hydrophobic and soluble in alcohols.
The Delta baryons are a family of subatomic particle made of three up or down quarks.
Cholestane is a saturated tetracyclictriterpene. This carbon-27 biomarker is produced by diagenesis of cholesterol and is one of the most abundant biomarkers in the rock record. Presence of cholestane in environmental samples are commonly interpreted as an indicator of animal life and/or traces of O2, as animals are known for exclusively producing cholesterol, and thus has been used to draw evolutionary relationships between ancient organisms of unknown phylogenetic origin and modern metazoan taxa. Cholestane is made in low abundance by other organisms (e.g., rhodophytes), but because these other organisms produce a variety of sterols it cannot be used as a conclusive indicator of any one taxa. It is often found in analysis of organic compounds in petroleum.
Amorolfine, is a morpholine antifungal drug that inhibits Δ14-sterol reductase and cholestenol Δ-isomerase, which depletes ergosterol and causes ignosterol to accumulate in the fungal cytoplasmic cell membranes. Marketed as Curanail, Loceryl, Locetar, and Odenil, amorolfine is commonly available in the form of a nail lacquer, containing 5% amorolfine hydrochloride as the active ingredient. It is used to treat onychomycosis. Amorolfine 5% nail lacquer in once-weekly or twice-weekly applications has been shown in two studies to be between 60% and 71% effective in treating toenail onychomycosis; complete cure rates three months after stopping treatment were 38% and 46%. However, full experimental details of these trials were not available and since they were first reported in 1992 there have been no subsequent trials.
Hexachlorocyclohexane (HCH) is any of several polyhalogenated organic compounds consisting of a six-carbon ring with one chlorine and one hydrogen attached to each carbon. There are many isomers for this structure, differing by the stereochemistry of the individual chlorine substituents on the cyclohexane. It is sometimes erroneously called "benzene hexachloride" (BHC). They have been used as models for analyzing the effects of different geometric positions of the large atoms with dipolar bonds on the stability of the cyclohexane conformation. Some isomers are pesticides.
In enzymology, a cholestenol Delta-isomerase is an enzyme that catalyzes the chemical reaction
A steroidogenesis inhibitor, also known as a steroid biosynthesis inhibitor, is a type of drug which inhibits one or more of the enzymes that are involved in the process of steroidogenesis, the biosynthesis of endogenous steroids and steroid hormones. They may inhibit the production of cholesterol and other sterols, sex steroids such as androgens, estrogens, and progestogens, corticosteroids such as glucocorticoids and mineralocorticoids, and neurosteroids. They are used in the treatment of a variety of medical conditions that depend on endogenous steroids.
Cholestenol is a sterol that has been found in the skins of rats. It can be converted to cholesterol in mammals. Delta-7-cholestenol is also known as lathosterol.
