81 resultados para Lead zirconate-titanate


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Cadmium and lead were determined in fruit and vegetable produce (~1300 samples) collected from a field and market basket study of locally grown produce from the South-West of Britain (Devon and Cornwall). These were compared with similarly locally grown produce from the North-East of Britain (Aberdeenshire). The concentrations of cadmium and lead in the market basket produce were compared to the maximum levels (ML) set by the European Union (EU). For cadmium 0.2% of the samples exceeded the ML, and 0.6% of the samples exceeded the ML for lead. The location of cadmium and lead in potatoes was performed using laser ablation ICP-MS. All tested samples exhibited higher lead concentrations, and most exhibited increased concentrations of cadmium in the potato skin compared to the flesh. The concentrations of cadmium and lead found in fruits and vegetables sampled during this study do not increase concern about risk to human health.

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Raptors that consume game species may ingest lead fragments or shot embedded in their prey's flesh. Threatened Spanish imperial eagles Aquila adalberti feed on greylag geese in southern Spain in winter, and often ingest lead shot. We analysed bone and feather samples from 65 Spanish imperial eagle museum specimens collected between 1980 and 1999, to investigate the prevalence of elevated lead concentrations. Four of 34 birds (12%) had very elevated bone lead concentrations. All four birds were young and the concentrations were outliers to the distribution, suggesting probable exposure to lead gunshot. Excluding these elevated lead outliers, bone lead concentrations were correlated with the bird's age at death. Three of 41 feathers (7%) had elevated lead concentrations, indicative of high exposure during feather formation. When these outliers were omitted, feather lead concentration was correlated with the age of museum specimens, suggesting that a high proportion of feather lead was exogenous, deposited after specimen collection. Therefore, careful interpretation of feather lead concentrations is required to separate endogenous and exogenous lead. We discuss the potential significance of lead poisoning in Spanish imperial eagles and other raptors, and recommend measures for its reduction. © 2004 Elsevier Ltd. All rights reserved.

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In order to investigate the compatibility of candidate structural materials with liquid metals, two kinds of ferritic/martensitic steels were chosen to contact with lead–bismuth eutectic in sealed quartz–glass tubes. The corrosion exposures were for 500 and 3000 h. Results showed that the oxidation layer and carbide dissolution layer on the two steels grew with contact time under oxygen unsaturated condition. Short-term corrosion behavior of a newly developed steel showed better lead–bismuth eutectic corrosion resistance than T91 at 873 K.

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Purpose: Researchers have demonstrated associations between trauma and psychosis. Childhood trauma, in particular, appears to be an important determinant. Recently, bullying has become considered a traumatic experience in its own right. This review aims to analyse research with prospective designs, which will enable conclusions about whether or not bullying causes psychosis.

Methods: A systematic review of the literature was carried out independently by two reviewers. Eligibility and quality assessment criteria were applied. A meta-analysis and narrative synthesis were then completed.

Results: Ten studies met inclusion criteria. Four used data from the same large database, and were combined as one. The majority provided confirmation that bullying appears to cause later development of psychosis. A meta-analysis yielded an unadjusted odds ratio (OR) of 2.148 [95% confidence interval (CI) 1.140–4.044].

Conclusions: The studies reviewed here suggest that bullying does predict the later development of psychotic symptoms. What is lacking from the literature is adequate investigation into other potential mediating factors. The current review highlights the significant role of bullying within this complex interaction. Potential mediating variables are explored, including a dose–response effect for the severity and frequency of victimization. Suggestions for targeting intervention are also suggested alongside clinical implications and recommendations for future research.

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In order to assess the susceptibility of candidate structural materials to liquid metal embrittlement, this work investigated the tensile behaviors of ferritic-martensitic steel in static lead bismuth eutectic (LBE). The tensile tests were carried out in static lead bismuth eutectic under different temperatures and strain rates. Pronounced liquid metal embrittlement phenomenon is observed between 200 °C and 450 °C. Total elongation is reduced greatly due to the liquid metal embrittlement in LBE environment. The range of ductility trough is larger under slow strain rate tensile (SSRT) test.