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ME Farago P Kavanagh R Blanks J Kelly G Kazantzis I Thornton PR Simpson JM Cook HT Delves GE Hall 《Canadian Metallurgical Quarterly》1998,123(3):451-454
Increasing Pt concentrations from vehicle catalysts have been reported from a number of countries. Analysis of Pt and Pd in soils and road dusts taken from areas of high and low traffic flows in SE England show concentrations of Pt in the range < 0.30-40.1 ng g-1 and Pd in the range < 2.1-57.9 ng g-1. Higher concentrations of Pt are associated with high traffic densities. Samples taken from streets of lower traffic flows were found to contain the lower concentrations of the ranges. Pilot studies of Pt concentrations in blood and urine using ICP-MS have been carried out. Platinum concentrations in whole blood were: precious metal workers, 780-2170, mean 1263 pmol l-1 (0.152-0.423, mean 0.246 microgram l-1); motorway maintenance workers, 645-810, mean 744 pmol l-1 (0.126-0.158, mean 0.145 microgram l-1); Imperial College staff, 590-713, mean 660 pmol l-1 (0.115-0.139, mean 0.129 microgram l-1). Platinum concentrations in urine in pmol Pt per mmol creatinine were: precious metal workers, 122-682, mean 273 [0.21-1.18, mean 0.47 microgram Pt (g creatinine)-1]; motorway maintenance workers, 13-78, mean 33.7 [0.022-0.135, mean 0.058 microgram Pt (g creatinine)-1]; Imperial College staff, 28-130, mean 65.6 [0.048-0.224, mean 0.113 microgram Pt (g creatinine)-1]. Detection limits were 0.03 microgram l-1 for both blood and urine. The possible health effects of increasing Pt in the environment are discussed. Platinum provides an excellent example of the significance of speciation in metal toxicity. Platinum allergy is confined to a small group of charged compounds that contain reactive ligand systems, the most effective of which are chloride ligand systems. Metallic Pt is considered to be biologically inert and non allergenic and since the emitted Pt is probably in the metallic or oxide form, the sensitising potential is probably very low. Platinum from road dusts, however, can be solubilised, and enter waters, sediments, soils and the food chain. There is at present no evidence for any adverse health effects from Pt in the general environment, particularly allergic reactions. 相似文献
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The long-term corrosion rate of passive iron in anaerobic alcaline solutions Gas generation is an important issue in safety assessments of low and intermediate level radioactive repositories. In this connection the hydrogen production from corrosion of passive iron in saturated calcium hydroxide, in dilute alkali hydroxide and cement porewater solutions has been determined. The measurements were performed manometrically using fusion sealed glass cells, the measurement periods being between 275 and 560 days. In 0.1 M and 0.04 M alkali hydroxide solutions the initial hydrogen generation rate was 12 mmol/m2yr corresponding to a linear corrosion rate of 64 nm/yr. The reaction rate decreases with time. The smallest value obtained after 330 days is 0.3 mmol/m2yr corresponding to 1.5 nm/yr. The influence on iron of the saturated calcium hydroxide solution and the calcic porewater solutions differs from that of the alkali hydroxide solutions. At pH 12.5 the hydrogen generation rate remains practically constant up to breaking off the experiment, the value being about 1 mmol/m2yr corresponding to 5 nm/yr. 相似文献
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Simpson Jeffry A.; Rholes William S.; Nelligan Julia S. 《Canadian Metallurgical Quarterly》1992,62(3):434
Examined how adult attachment styles moderate spontaneous behavior between dating couples when 1 member of the dyad is confronted with an anxiety-provoking situation. 83 dating couples were unobtrusively videotaped for 5 min in a waiting room while the woman waited to participate in an "activity" known to provoke anxiety in most people. Independent observers then evaluated each partner's behavior on several dimensions. Results revealed that persons with more secure attachment styles behaved differently than persons with more avoidant styles in terms of physical contact, supportive comments, and efforts to seek and give emotional support. Findings are discussed in the context of theory and research on attachment. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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Backward priming was investigated under conditions similar to those used in lexical ambiguity research. Ss received prime-target word pairs that were associated either unidirectionally (BABY-STORK) or bidirectionally (BABY-CRY). In Exp 1, targets were presented 500 ms following the onset of visual primes, and Ss made naming or lexical decision responses to the targets. Forward priming was obtained in all conditions, while backward priming occurred only with lexical decision. In Exp 2, primes were presented auditorily, either in isolation or in a sentence. Targets followed the offset of the primes either immediately or after 200 ms. Backward priming occurred with both response tasks, but only when the prime was an isolated word. Backward priming decreased over time with the naming task, but not with lexical decision. These results suggest that the locus of the backward priming effect is different for the 2 response tasks. Results support a context-independent view of lexical access. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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We conducted a retrospective review of 155 spinal operations at our institution to determine the efficacy of intraoperative salvage. Addition of intraoperative salvage had little effect on the success of a preoperative autologous donation program. Only patients with operative blood loss > 2,000 ml (12% of patients) benefited from this expensive source of autologous blood. The technique tended to be most effective in children aged 16-18 years. Use of intraoperative salvage for all pediatric spinal procedures is neither necessary nor cost effective. 相似文献
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TI Lezhen SA Kramarev EA Dmitrieva LA Palatnaia VN Blagodatny? 《Canadian Metallurgical Quarterly》1996,68(6):104-108
Practical application of turbidimetrical method for the diagnosis of haemostasis disorders in babies with acute intestinal infections (AII) is described. The results of plasma biochemical analysis show that disturbances in balance between coagulation and fibrinolytic systems takes place in patients with this pathology. The correlation between biochemical parameters and clinical characteristics is observed. As follows from our data, the phase of the haemostasis disorders in babies with AII does not depend on etiology of the disease, but indicates its severity. 相似文献