(n.) Formerly, the metallic base of a fixed alkali, or alkaline earth; -- applied by Sir H. Davy to sodium, potassium, and some other metallic substances whose metallic character was supposed to be not well defined.
(n.) Now, one of several elementary substances which in the free state are unlike metals, and whose compounds possess or produce acid, rather than basic, properties; a nonmetal; as, boron, carbon, phosphorus, nitrogen, oxygen, sulphur, chlorine, bromine, etc., are metalloids.
(a.) Having the appearance of a metal.
(a.) Having the properties of a nonmetal; nonmetallic; acid; negative.
Example Sentences:
(1) As with other elements, the interest here is the potential effect of environmental acidification on environmental behavior in ways that are relevant to human exposure to these metalloids.
(2) The effects of the well established carcinogenic metals or metalloids (As, Be, Cr, Ni), hypothetically carcinogenic but well-established cocarcinogenic metals (Cd, Pb, Co) and weak co-carcinogenic metals (Al, Cu, Fe, Zn) and the antagonism between Mg and these metals were studied on the ionic transfer through the isolated human amnion.
(3) New information about the toxic effect of some metals and metalloids and about their kinetics of absorption, distribution and excretion in experimental animals, and particularly in man, is necessary for elaborating suitable biological exposure tests.
(4) Selenium (Se) is a metalloid with chemical properties closed to those of sulfur, but they can not substitute for one another in vivo.
(5) In order to invalidate or confirm the affirmation that non antithyroid sulphide molecules alter the measure of the thyroid fixation rate of iodine 131 we undertook on the rat: on one hand a kinetic study of thyroid fixation of sodium thiosulfate labelled with sulphur 35, which showed a very low captation not exceeding 0,01% of injected radioactivity; on the other hand the study of the effects of some sulphide molecules on thyroid fixation of iodine 131 in the rat: sodium thiosulfate, association of sodium thiosulfate + metalloidal sulphur + methionine, carbutamide and dimethylsulfoxyde in various kinds of dose administration and periods.
(6) Main group metals and metalloids were surveyed for the identification of species that can either donate or accept methyl groups.
(7) Diethyl maleate, indocyanine green and sulfobromophthalein (BSP), which decreased biliary excretion of GSH, significantly diminished excretion of antimony and bismuth into bile indicating that hepatobiliary transport of these metalloids is GSH-dependent.
(8) In recent years, however, it has become clear that several metals and metalloids undergo transformations in mammalian tissues and that metabolism may have important implications in clinical pharmacology, toxicology, and environmental health.
(9) Proportionally to their biliary excretion rates, these metalloids generate increased biliary excretion of GSH probably because they are transported from liver to bile as unstable GSH complexes.
(10) The potential impact of acidic deposition on As and Se in soils cannot readily be assessed with respect to human exposure, but it would appear that the behavior of these metalloids in poorly buffered, poorly immobilizing soils, e.g., sandy soils of low metal hydrous oxide content, would be most affected.
(11) Biological monitoring of exposure to metals and metalloids involves not only determination of these elements in selected body fluids and tissues but, in some cases, also determination of a certain biochemical indicator which signalises the presence of the monitored element in the organism.
(12) Methylcobalamin (methyl-B12) has been implicated in the biomethylation of the heavy metals (mercury, tin, platinum, gold, and thallium) as well as the metalloids (arsenic, selenium, tellurium and sulfur).
(13) Details of the kinetics and mechanisms for biomethylation of arsenic are presented, with special emphasis on synergistic reactions between metal and metalloids in different oxidation states.
(14) The exchange rates for metals and metalloids between sediments, soils, water and aquatic biota are discussed in terms of normal and acidified ecosystems.
(15) The occupational history highlighted heavy exposure to inhalation of ash derived from mineral oil combustion and containing several elements, metals and metalloids, including vanadium and nickel.
(16) Available information on acid precipitation and the environmental behavior of these metalloids do, however, permit some preliminary conclusions to be drawn.
(17) Over the past 15 years, these methods have led to the establishment of causal factors in metal- and metalloid-induced toxicity.
(18) The present studies in rats aimed to determine whether antimony and bismuth, other metalloids in group Va of the periodic table, also possess similar properties.
(19) The abnormal life--potentially the death--of the cell can be restored by a metalloid--lithium--which is nearly as common as sodium in the mineral world.
(20) In this report we present details of the mechanisms for biological methylation of certain metals and metalloids with special emphasis on those elements that are widely dispersed in the biosphere.
Sodium
Definition:
(n.) A common metallic element of the alkali group, in nature always occuring combined, as in common salt, in albite, etc. It is isolated as a soft, waxy, white, unstable metal, so readily oxidized that it combines violently with water, and to be preserved must be kept under petroleum or some similar liquid. Sodium is used combined in many salts, in the free state as a reducer, and as a means of obtaining other metals (as magnesium and aluminium) is an important commercial product. Symbol Na (Natrium). Atomic weight 23. Specific gravity 0.97.
Example Sentences:
(1) 5-Azacytidine (I) stability was increased approximately 10-fold over its stability in water or lactated Ringer injection by the addition of excess sodium bisulfite and the maintenance of pH approximately 2.5.
(2) The mobility on sodium dodecyl sulfate-polyacrylamide gel electrophoresis is anomalous since the undenatured, cross-linked proteins have the same Stokes radius as the native, uncross-linked alpha beta gamma heterotrimer.
(3) We report a series of experiments designed to determine if agents and conditions that have been reported to alter sodium reabsorption, Na-K-ATPase activity or cellular structure in the rat distal nephron might also regulate the density or affinity of binding of 3H-metolazone to the putative thiazide receptor in the distal nephron.
(4) In the fall of 1975, 1,915 children in grades K through eight began a school-based program of supervised weekly rinsing with 0.2 percent aqueous solution of sodium fluoride in an unfluoridated community in the Finger Lakes area of upstate New York.
(5) No statistically significant difference was found between sodium hyaluronate and hydroxypropylmethylcellulose (HPMC).
(6) Plasma membranes were isolated from rat kidney and their transport properties for sodium, calcium, protons, phosphate, glucose, lactate, and phenylalanine were investigated.
(7) These were an isotonic solution of sodium chloride (900 micrograms NaCl in 0.1 ml), histamine (100 mu g in 0.1 mu l), phytohaemagglutinin (200 mu g in 0.1 ml), and a staphylococcus lysate (STAVA).
(8) Sodium intake affects K excretion, increases in intake resulting in a higher rate of K excretion.
(9) Infusion of sodium lactate associated with isoproterenol could be used to combat the depressent effects of betablockers in patients with cardiac disorders.
(10) The influence of calcium ions on the electrophoretic properties of phospholipid stabilized emulsions containing various quantities of the sodium salts of oleic acid (SO), phosphatidic acid (SPA), phosphatidylinositol (SPI), and phosphatidylserine (SPS) was examined.
(11) Under these conditions, arterial pressure and sodium balance remained stable.
(12) Densitometric analysis of myofibrillar proteins separated with sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicated that troponin I and troponin T were degraded during 60 minutes of CGI.
(13) The sodium level of the ascitic fluid determined in 5 cases was higher than that of serum.
(14) These studies also suggest at least two mechanisms for uric acid reabsorption; one sodium dependent, the other independent of sodium and water transport.
(15) After local injection of sodium iodoacetate osteoarthritic reactions will progress within 2-4 months.
(16) The free nucleoside IV was obtained by removal of blocking groups by sodium methoxide catalyzed deacylation, deionization under reducing atmosphere, and chromatography on neutral alumina.
(17) L-Leucine-(14)C and sodium pyruvate-3-(14)C were employed to measure globin and heme synthesis, respectively.
(18) Defects of several membrane proteins were found with sodium dodecyl sulfate--polyacrylamide gel electrophoresis.
(19) PYY inhibited the reduction in net absorption of sodium chloride and water evoked by vasoactive intestinal peptide (VIP), but did not affect the VIP-evoked increase in net potassium secretion.
(20) Its metabolism was studied in the hamster in comparison with sodium 3 alpha, 7 alpha-dihydroxy-24-nor-5 beta-cholane-23-sulfonate and sodium taurochenodeoxycholate.