نتایج جستجو برای: chromium plating
تعداد نتایج: 32212 فیلتر نتایج به سال:
Objectives. The main objective of this study was to assess the chromium exposure levels in printing workers. The study evaluated the airborne, serum, and urinary chromium levels and determines any correlation between level of chromium in specimen and airborne chromium levels. Material and Methods. A cross-sectional study was conducted with 75 exposed and 75 matched nonexposed subjects. Air brea...
The types of reactive intermediates generated upon reduction of chromium(VI) by glutathione or hydrogen peroxide and the resulting DNA damage have been determined. In vitro, reaction of chromium(VI) with glutathione led to formation of two chromium(V) complexes and the glutathione thiyl radical. When chromium(VI) was reacted with DNA in the presence of glutathione, chromium-DNA adducts were obt...
The interaction of chromium oxide with Alz03, TiOz and SiO? supports is investigated with Raman spectroscopy. The influence of the nature of the oxide support, calcination temperature and chromium oxide loading upon the molecular state of the supported chromium oxide is determined. The Raman studies reveal that the oxide supports stabilize the chromium oxide as Cr(V1) in tetrahedral coordinatio...
Basic chromium sulphate is the most versatile and common tanning agent in the leather industry. Under certain circumstances, the oxidation of the trivalent chromium salts into the hexavalent compounds, which are used in leather manufacture, is a crucial issue. In this study, different proportions of basic chromium sulphate were used in tanning and re-tanning processes according to a commonly us...
We previously showed that carcinogenic nickel, arsenic, and chromium(VI) compounds induced anchorage independence (AI) in diploid human fibroblastic cells (HFC) derived from foreskins (K. A. Biedermann and J. R. Landolph, Cancer Res., 47: 3815-3823, 1987). To elucidate the role of the valence state of chromium and solubility of chromium compounds in inducing AI, we studied the ability of solubl...
Chromium supplements are thought to be the second most commonly taken nutritional supplement, used by an estimated 10 million Americans (1). Chromium is an essential element in humans, and deficiency is associated with the development of diabetes, which was first noted in patients receiving long-term parenteral nutrition before the advent of routine chromium supplementation (2,3). In these pati...
Chromium is a naturally occurring, toxic heavy metal used in many industrial processes. The U.S. Department of Labor's Occupational Safety and Health Administration has established specific limits for occupational exposure levels of chromium and guidelines for medical surveillance of individuals who have been exposed to chromium. The author presents a case in which a 54-year-old man who had bee...
Mechanical damage to Gram-negative bacteria by surface plating with the Drigalski-spatula technique.
Colony counting by spreading bacterial suspensions on plating media by various techniques is of general concern. Comparative studies between hand plating (Drigalski-spatula technique) for different time intervals and spiral plating resulted in significant differences in colony counts. Lower counts of Gram-negative bacteria were obtained by using hand plating for more than 10s, compared with sho...
This study evaluated the toxicity of hexavalent and trivalent compounds of chromium to the pacu, Piaractus mesopotamicus, in acute exposures of 96 h through mortality and histopathological responses. Hexavalent potassium dichromate was more toxic than trivalent compounds of chromium chloride, chromium oxide and chromium carbochelate. Sufficient mortalities occurred only with potassium dichromat...
Many orthopaedic implants are composed of alloys containing chromium. Of particular relevance is the increasing number of Cobalt Chromium bearing arthroplasies being inserted into young patients with osteoarthritis. Such implants will release chromium ions. These patients will be exposed to the released chromium for over 50 years in some cases. The subsequent chromium ion metabolism and redistr...
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