(n.) An important ore of iron, the sesquioxide, so called because of the red color of the powder. It occurs in splendent rhombohedral crystals, and in massive and earthy forms; -- the last called red ocher. Called also specular iron, oligist iron, rhombohedral iron ore, and bloodstone. See Brown hematite, under Brown.
Example Sentences:
(1) The third aerosol, "gamma-oxide," has a MMAD of 0.73 micrometer and has crystalline subunits 0.2 micrometer in diameter; it is a magnetic form of hematite, gamma-Fe2O3.
(2) This case-control (case-referent) study concerns a worker population with high exposure to dust of iron oxides, particularly hematite, and with some impurities of pentavalent arsenic and other metals.
(3) The iron-oxides (superfine hematite) are eroded from the Peron Sandstone exposed in some coastal cliffs and constitute up to 2% of substrate sediments near these cliffs.
(4) Inside the molluscs, lower pH conditions cause reversal of the hematite charge and the cadmium is released and accumulated by the organism.
(5) These fungi were incubated with the following iron-containing minerals: augite, hornblende, biotite, magnetite, hematite, and the igneous rock granodiorite.
(6) The "feathers" hematite has a man median aerodynamic diameter (MMAD) of 0.17 micrometer and a large surface area because it is an agglomerate of units 0.005 micrometer in diameter.
(7) Slate is a metamorphic rock comprising silica, aluminum silicates, and small amounts of chlorite, hematite, magnetite, and various carbonates.
(8) In a retrospective cohort mortality study of 10,403 Minnesota iron-ore (hematite) miners no excesses of lung cancer mortality were found among either underground (Standardized mortality ratio [SMR] = 100) or above ground (SMR = 88) miners.
(9) The "birdshot" hematite has a MMAD of 0.31 micrometer, but has a smaller surface area because the subunits are 0.03 micrometer in diameter.
(10) Fibrous dusts (chrysotile, glass fibers, nemalite, palygorscite, and gypsum) and granular dusts (actinolite, biotite, hematite, pectolite, sanidine, and talcum) were injected intraperitoneally into rats.
(11) The mortality risk of nonmalignant respiratory disease among hematite workers in the Longyan and Taochong mines of China was investigated in a retrospective cohort study covering the period 1970-1982.
(12) No direct link between the cadmium loads in molluscs and its concentration in the water or substrate sediment is evident, but the cadmium load in molluscs is usually highest where turbulence is high and the substrate sediment contains fine hematite.
(13) Iron oxides, particularly hematite, have been suspected for carcinogenic properties based on epidemiological observations and experimental data.
(14) This study reveals that cadmium in the water adsorbs extremely efficiently onto the surface of the hematite, which is negatively charged at the prevailing seawater pH of 8.15, and that suspended hematite particles are ingested by the molluscs.
Peroxide
Definition:
(n.) An oxide containing more oxygen than some other oxide of the same element. Formerly peroxides were regarded as the highest oxides. Cf. Per-, 2.
Example Sentences:
(1) The hypothesis that proteins are critical targets in free radical mediated cytolysis was tested using U937 mononuclear phagocytes as targets and iron together with hydrogen peroxide to generate radicals.
(2) The data indicate that ebselen is likely to be useful in the therapy of inflammatory conditions in which reactive oxygen species, such as peroxides, play an aetiological role.
(3) Furthermore, high-density catalase-positive--but not catalase-negative--E. coli can survive and multiply in the presence of competitive, peroxide-generating streptococci.
(4) Studies were conducted in isolated, buffer-perfused rat lungs to determine if prostaglandin (PG) E1 attenuated pulmonary edema provoked by hydrogen peroxide (H2O2).
(5) Spontaneous lipid peroxidation in washed human spermatozoa was induced by aerobic incubation at 32 C and measured by malonaldehyde production; loss of motility during the incubation was determined simultaneously.
(6) Changes in the plasma lipid composition are observed in patients and animals with malignancy and certain other diseases that are consistent with peroxidation of plasma lipoprotein lipids.
(7) Phenobarbital pretreatment increased peroxidation due to exposure of the cells to CCl4 but not that associated with NADPH addition.
(8) Both fatty acid composition and the degree of lipid peroxidation were measured in this study in 23 OTC fish oil preparations.
(9) With the use of two methods, measurement of conjugated dienes and thiobarbituric acid reactivity, brain lipid peroxidation could be documented as a result of exposure to CO at a concentration sufficient to cause unconsciousness.
(10) In the cytochrome P-450-reconstituted system, CCl4 stimulated NADPH-dependent lipid peroxidation of the system containing the P-450 form to a much greater extent than that of the system containing the P-448 form.
(11) The in vivo hepatic lipid peroxide content of rats was increased by aspirin or 4-pentenoic acid (4-PA) administration but was decreased by clofibrate (CPIB) administration.
(12) A water based 5% benzoyl peroxide gel (Benzac W5) was compared with topical 1% clindamycin phosphate solution (Cleocin T) in the treatment of acne vulgaris using a randomized, investigator blind study design.
(13) M & B 22948, a guanosine 3',5'-cyclic monophosphate (cGMP)-selective phosphodiesterase inhibitor, enhanced the vasodilation or relaxation to the peroxide in both preparations.
(14) Accordingly, the 30-fold differences in aging rate among the mammalian species could be determined in part by peroxidation defense processes.
(15) Hence, the 2-NOF:N-acetoxy-N-2-fluorenylacetamide ratios reflect the relative contributions of the two peroxidative pathways to the metabolism of N-OH-2-FAA.
(16) Vanadate-dependent oxidation of either pyridine nucleotide was inhibited by the addition of either superoxide dismutase or catalase, indicating that both superoxide and hydrogen peroxide may be intermediates in the process.
(17) Compared with 39 control subjects, 39 antioxidant-supplemented men experienced the following net reductions during the double-blind period: 20% (P = 0.012) in serum lipid peroxides, 24% (P = 0.035) in ADP-induced platelet aggregation, 42% (P = 0.040) in the rate of ATP release during aggregation, 51% (P = 0.018) in serum (platelet-produced) thromboxane B2, and 29% (P = 0.024) in plasma beta-thromboglobulin concentration.
(18) Protection against O2 toxicity was assessed in terms of lethality and pulmonary edema and of lung lipid peroxidation (assessed by measuring malondialdehyde).
(19) Serum GSSRase activity, however, was significantly decreased while serum vitamin E, and lipid peroxidation levels were significantly increased.
(20) From these results it is suggested that the lipid peroxidation of the brush-border membranes by addition of dithiothreitol plus Fe2+ is sensitively changed with change in ionic strength.