(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.
Nonmetal
Definition:
(n.) Any one of the set of elements which, as contrasted with the metals, possess, produce, or receive, acid rather than basic properties; a metalloid; as, oxygen, sulphur, and chlorine are nonmetals.
Example Sentences:
(1) For gas chromatographic eluents a microwave induced plasma (MIP) emission detector has two important features for a wide range of nonmetals.
(2) Thus, transient resistance to cis-DDP can be produced by a nonmetal inducer of metallothionein in nontransformed cells.
(3) A cross-sectional survey of Canadian hospitals carried out in 1984 revealed a large diversity of practices in the use of blood glucose meters and nonmeter blood glucose reagent strips and of providers of this service.
(4) Some of this heterogenous group of metals and nonmetals have been shown to be essential for life or for the well-being of animals, including man; others possess toxic properties, while yet others are probably there as contaminants.
(5) Patients receiving the unicompartmental arthroplasty were treated with nonmetal-backed polyethylene tibial components.
(6) Nonmetal materials are used for the instrument construction in order to eliminate potentially disturbing eddy currents.
(7) A postal questionnaire was sent to men employed in the metal industry, certain other types of nonmetal industries, and other types of employment in which the factors suspected to influence sperm quality were not present.
(8) Liquid Crystals having color play centered at different temperatures are arranged on metal coated and nonmetal coated dielectric substrates and used to monitor electromagnetic radiation.
(9) Potassium ferrate (K2FeO4) is shown in this work to be an effective means to remove toxic metals and nonmetals from aqueous solution.
(10) The nonmetal biomaterials were placed in glass tubes containing the different fluids at room temperature for 5 days.
(11) Among them there were 109 eyes with nonmetal foreign bodies, 55 eyes with metal foreign bodies and three eyes with foreign bodies of unknown nature.
(12) (v) Transport was temperature-dependent with a Q(10) of greater than 2 between 3 and 40 C. Transport decreased rapidly above 40 C. (vi) Ethylenediaminetetraacetate (sodium salts, pH 6) had no effect, nor was there any stimulation by metal or nonmetal ions.
(13) A large stent diameter and a large open or nonmetal surface may cause less intimal hyperplasia, but nonturbulent, fast arterial flow is probably the most important factor in ensuring long-term patency of the vessel.
(14) Thus, for example, L-Phe binds close to the metal ion to form a 1:1 complex, whereas D-Phe binds stepwise, first to a nonmetal site and then to the metal ion to form a 2:1 complex.
(15) Among factors affecting the reliability of heart valve prostheses (HVP) the following ones are of a great importance: the temperature and the duration of soldering a big clamp of the HVP, the occurrence of nonmetal inclusions in the original material (the alloy 45KXBH), etc.
(16) The estimated rate constants for the metal- and nonmetal-catalyzed sulfuryl transfers differ by less than an order of magnitude and are approximately 1000-fold slower than the corresponding phosphate transfers.
(17) Heavy metals caused the acute phase within 24 hr, nonmetals and Metacid-50 within 48 hr exposure.
(18) High-grade titanium ports reportedly produce minimal artifacts, and those of nonmetal materials reportedly produce no artifacts.