(n.) A certain property of a body, expressed as a measurable quantity, such that when there is no communication of heat the quantity remains constant, but when heat enters or leaves the body the quantity increases or diminishes. If a small amount, h, of heat enters the body when its temperature is t in the thermodynamic scale the entropy of the body is increased by h / t. The entropy is regarded as measured from some standard temperature and pressure. Sometimes called the thermodynamic function.
Example Sentences:
(1) This formalism allows resolution of the intrinsic protein folding-unfolding parameters (enthalpy, entropy, and heat capacity changes) as well as the ligand interaction parameters (binding stoichiometry, enthalpy, entropy, and heat capacity changes).
(2) Dictated by underlying physicochemical constraints, deceived at times by the lulling tones of the siren entropy, and constantly vulnerable to the vagaries of other more pervasive forms of biological networking and information transfer encoded in the genes of virus and invading microorganisms, protein biorecognition in higher life forms, and particularly in mammals, represents the finely tuned molecular avenues for the genome to transfer its information to the next generation.
(3) The Skilling maximum entropy method (MEM) algorithm is applied to in vivo spectra and provides an estimate of the spectrum that is operator-independent, although at the expense of some negative bias.
(4) The changes in E degrees' and the standard entropy (delta S degrees') and enthalpy (delta H degrees') of reduction in the mutant proteins were determined relative to values for wild type; the change in E degrees' at 25 degrees C was about -200 millivolts for the Glu and Asp mutants, and about -80 millivolts for the Asn mutant.
(5) It is shown that the invariant integral, viz., the Kolmogorov second entropy, is eminently suited to characterize EEG quantitatively.
(6) The thermodynamic quantities of change in free energy (delta G degree'), change in enthalpy (delta H degree') and change in entropy (delta S degree') were determined for the interaction of norepinephrine with the alpha-1 adrenoceptor of vascular smooth muscle.
(7) This paper is concerned with the connection between two classes of population variables: measures of population growth rate--the Malthusian parameter, the net reproduction rate, the gross reproduction rate, and the mean life expectancy; and measures of demographic heterogeneity--population entropy.
(8) Recent studies from this laboratory reveal distinct differences in the thermodynamic binding mechanisms between m-AMSA and o-AMSA (Wadkins & Graves, 1989), with the m-AMSA-DNA interaction being an enthalpy-driven process while the binding of o-AMSA to DNA is characterized by more positive entropy values.
(9) Such replacements are presumed to restrict the degrees of freedom of the unfolded protein and so decrease the entropy of unfolding [B. W. Matthews, H. Nicholson, and W. J. Becktel (1987) Proceedings of the National Academy of Science USA Vol.
(10) The overall enthalpy change is negative and the overall entropy change is positive for the simultaneous binding of AMP-PNP and L-glutamate or of AMP-PNP and L-Met-(S)-sulfoximine to the enzyme.
(11) The part of entropy depending on the number of elements of the system (cells, individuals, etc.)
(12) 2 orders of magnitude higher than that of free calmodulin; the latter is even more entropy driven (delta H0 = 7.2 kJ X site-1; delta S0 = 158 J X K-1 X site-1) than binding to free calmodulin (delta H0 = 4.7 kJ X site-1; delta S0 = 112 J X K-1 X site-1), thus underlining the importance of hydrophobic forces in the free energy coupling involved in the ternary complex.
(13) Thus, Ca2+ binding to the Ca2+-Mg2+ sites is driven by both enthalpy and entropy and the lower Ca2+ affinity for sites 3 and 4 is reflected in the lower entropy of Ca2+-binding.
(14) This paper presents a unified account of the properties of the measures, Malthusian parameter and entropy in predicting evolutionary change in populations of macromolecules, cells and individuals.
(15) The model stresses that solutes do not act at a single site, but on both states in an equilibrium, and that the perturbation is determined by the difference in entropy.
(16) The "entropy potential" of the membrane may have its molecular origin in the excitation of the hydrocarbon chains to a more disordered configuration and may play a more important role in membrane partition equilibria than the classical hydrophobic effect.
(17) The entropy of activation of kcat for the human enzyme was further decomposed into partially compensating electrostatic(es) (delta S*es = +15.1 cal mol-1 K-1) and nonelectrostatic(nes) (delta S*nes = -19.1 cal mol-1 K-1) terms.
(18) Basic free energy level differences are related to the first-order rate constants for transitions between states while gross free energy differences, along with the corresponding fluxes, determine the rate of entropy production in the system.
(19) Their high-affinity binding component was entropy driven at 2 degrees C and became enthalpy driven when the incubation temperature was increased.
(20) As far as information in nervous systems is connected with an element of energy normalization that is much greater than the scales of molecular energy of single atoms, physical and information self-organization can simultaneously either correlate or be sufficiently independent, because entropy corresponds to statically unstable point, with its output being natural in different ways.
Irreversible
Definition:
(a.) Incapable of being reversed or turned about or back; incapable of being made to run backward; as, an irreversible engine.
(a.) Incapable of being reversed, recalled, repealed, or annulled; as, an irreversible sentence or decree.
Example Sentences:
(1) The specific limited trypsinolysis of bacteriophage T7 RNA polymerase (T7RP) was performed in the presence of various components of the polymerase reaction and some GTP-analogs--irreversible inhibitors of the enzyme.
(2) At 24 or 48 hours after ischemia, 63Ni, 99TcO4, and 22Na were preferentially concentrated in the damaged striatum and hippocampus, whereas 65Zn, 59Fe, 32PO4, and 147Pm did not accumulate in irreversibly injured tissue.
(3) The illumination of the F1-ATPase complexes with NAB-ADP or NAB-GDP leads to the covalent binding of one nucleotide analogue molecule to the enzyme and to the irreversible inactivation of F1-ATPase.
(4) The inhibition was irreversible, as well as time and concentration dependent, which indicates a suicide-inhibition type of metabolism.
(5) It is unclear if the changes in high-energy phosphates during endotoxin shock cause irreversibility.
(6) These studies indicate that, in three models of acute liver injury, the net influx of calcium across the plasma membrane is increased early in the evolution of the injury before irreversible damage occurs.
(7) The kinetics of association of the radioligand suggested the presence of a rapidly associating, reversible binding site, and a slowly associating, apparently irreversible one.
(8) The high capacity of irreversible synthetic-state, smooth muscle cells to bind and accumulate beta-VLDL in contrast to the relative immunity of contractile cells may be relevant to the genesis of atherosclerosis in the rabbit and possibly also in humans.
(9) In the MVD, all esters appeared to irreversibly block the agonist effect of morphine, but none of the compounds irreversibly antagonized [D-Ala2,D-Leu5]enkephalin to a significant degree.
(10) The coronary vasoconstrictor response produced by ibopamine was inhibited completely by the irreversible alpha-adrenoceptor antagonist, phenoxybenzamine, whereas the response produced by epinine was transformed into relaxation which was inhibited by the beta-adrenoceptor antagonist, propranolol.
(11) It is concluded that vasectomy should no longer be considered an irreversible procedure.
(12) No correlation occurred between specific immunopatterns and irreversible brochopulmonary lesions.
(13) In patients under anti-epileptic therapy it is readily possible for the clinical picture to be concealed, and this may then result in irreversible damage due to the disturbance of metabolism remaining uninfluenced.
(14) When tissue metabolism was irreversibly inhibited by exposure to formaldehyde, hydrogen ion concentration and pCO2 were significantly decreased in the mucosal side of the chamber compared with the viable gall bladder.
(15) More than 20 years ago Olney and his colleagues described the 'Excitotoxic Hypothesis' which postulates that, in addition to its normal function in the healthy brain, glutamate can kill neurons by prolonged, receptor-mediated depolarization resulting in irreversible disturbances in ion homeostasis.
(16) Hypercalcaemia is a common disorder, which frequently requires specific treatment either to control symptoms, or to prevent the development of irreversible organ damage or death.
(17) The kinetics of inactivation of the Mg(2+)-containing enzyme in 8 M-urea at higher temperatures suggest a partially unfolded Mg-A-B* dimer intermediate with 50% activity, followed by irreversible inactivation coincident with the appearance of unfolded monomer.
(18) The rate of the irreversible damage to the reaction center II, caused by exposure of spinach thylakoids to high light was slowed down by anaerobic conditions and by lowering the temperature.
(19) Rheumatoid arthritis, a disease of unknown aetiology, has a multifactorial pathogenesis which may result in irreversible connective tissue destruction and loss of joint function.
(20) Although neither patient exhibited a toxic effect, these levels may be associated with an increased risk of thioridazine-induced irreversible pigmentary retinopathy, cardiac arrhythmias, and tardive dyskinesia.