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1.
During a 7-year period, 117 fetal karyotypes were available from 131 genetic amniocenteses. These procedures were performed between 14 and 37 weeks' gestation for the following abnormal ultrasound findings: (1) intrauterine growth retardation (IUGR)—61 cases; (2) fetal malformation—71 cases; and (3) amniotic fluid volume (AFV) abnormality—60 cases. Chromosomal abnormalities were identified in 19 cases (16.2 per cent). Aneuploidy was 2.5 times as frequent in the presence of malformations than in their absence. No correlation was demonstrated between specific fetal malformations and specific chromosomal abnormalities. Aneuploidy was also twice as frequent in the presence of symmetrical IUGR than in its absence. No chromosomal abnormalities were found among eight cases of asymmetrical IUGR. Four cases of aneuploidy presented with isolated IUGR, three of these involving the X chromosome. The frequency of aneuploidy was the same with or without abnormalities of AFV (14.3 versus 16.4 per cent). No chromosomal abnormality was found associated with isolated AFV abnormalities.  相似文献   
2.
Heat and free chlorine are among the most efficient and commonly used treatments to inactivate enteric viruses, but their global inactivation mechanisms have not been elucidated yet. These treatments have been shown to affect at least the capsid proteins of viruses and thus may affect the surface properties (i.e. electrostatic charge and hydrophobicity) of such particles. Our aim was to study the effects of heat and free chlorine on surface properties for a murine norovirus chosen as surrogate for human norovirus. No changes in the surface properties were observed with our methods for murine norovirus exposed to free chlorine. Only the heat treatment led to major changes in the surface properties of the virus with the expression of hydrophobic domains at the surface of the particles after exposure to a temperature of 55 °C. No modification of the expression of hydrophobic domains occurred after exposure to 60 °C, and the low hydrophobic state exhibited by infectious and inactivated particles after exposure to 60 °C appeared to be irreversible for inactivated particles only, which may provide a means to discriminate infectious from inactivated murine noroviruses. When exposed to a temperature of 72 °C or to free chlorine at a concentration of 50 mg/L, the genome became available for RNases.  相似文献   
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Decabromodiphenyl ethane (deBDethane) is an additive flame retardant marketed as a replacement for decabromodiphenyl ether (decaBDE). The structures of the two chemicals are similar, and hence deBDethane may also become an environmental contaminant of concern. Environmental data on deBDethane are scarce. Since sewage sludge is an early indicator of leakage of these chemicals into the environment, an international survey of deBDethane and decaBDE levels in sludge was conducted. Samples were collected from 42 WWTPs in 12 different countries and analyzed with GC/LRMS. DeBDethane was present in sludge from all countries and may therefore be a worldwide concern. The levels of deBDethane in sludge samples from the Ruhr area of Germany were the highest so far reported in the literature (216 ng g−1 d.wt.). The [deBDethane]/[decaBDE] quotient for the whole data set ranged from 0.0018 to 0.83. High ratios were found in and around Germany where deBDethane imports are known to have been high and substitution of decaBDE with deBDethane is likely to have occurred. Low ratios were found in the USA and the UK, countries that have traditionally been large users of decaBDE. An estimate of the flux of deBDEthane from the technosphere via WWTPs to the environment within the European Union gave 1.7 ± 0.34 mg annually per person. The corresponding value for decaBDE was 41 ± 22 mg annually per person.  相似文献   
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Soil contamination by metals engenders important environmental and health problems in northern France where a smelter (Metaleurop Nord) was in activity for more than a century. This study aims to look at the long-term effects of the smelter after its closedown by combining data on the degree of soil contamination and the quality of the crops grown (agricultural crops and homegrown vegetables) in these soils for a better assessment of the local population’s exposure to Cd, Pb, and Zn. Seven years after the Metaleurop Nord closedown, (1) the agricultural and urban topsoils were strongly contaminated by Cd, Pb, and Zn; (2) the kitchen garden topsoils were even more polluted than the agricultural soils, with great variability in metal concentrations within the gardens studied; (3) a high proportion of the agricultural crops for foodstuffs did not conform with the European legislation; (4) for feedstuffs, most samples did not exceed the Cd and Pb legislation limits, indicating that feedstuffs may be an opportunity for most agricultural produce; and (5) a high proportion of the vegetables produced in the kitchen gardens did not conform with the European foodstuff legislation. The high contamination level of the soils studied continues to be a risk for the environment and the population’s health. A further investigation (part 2) assesses the associated potential health risk for local inhabitants through consumption of homegrown vegetables and ingestion of soil particles by estimating the site-specific human health assessment criteria for Cd and Pb.  相似文献   
5.
A combined semi-distributed hydrological model (CASCADE/QUESTOR) is used to evaluate the steady-state that may be achieved after changes in land-use or management and to explore what additional factors need to be considered in representing catchment processes. Two rural headwater catchments of the River Derwent (North Yorkshire, UK) were studied where significant change in land-use occurred in the 1990s and the early 2000s. Much larger increases in mean nitrate concentration (55%) were observed in the catchment with significant groundwater influence (Pickering Beck) compared with the surface water-dominated catchment (13% increase). The increases in Pickering Beck were considerably greater than could be explained by the model in terms of land-use change. Consequently, the study serves to focus attention on the long-term increases in nitrate concentration reported in major UK aquifers and the ongoing and chronic impact this trend is likely to be having on surface water concentrations. For river environments, where groundwater is a source, such trends will mask the impact of measures proposed to reduce the risk of nitrate leaching from agricultural land. Model estimates of within-channel losses account for 15–40% of nitrate entering rivers.  相似文献   
6.
Dry deposition of semi-volatile organic compounds (SVOC) is not currently treated in most chemical transport models of air quality and this omission has been identified as a possible major source of uncertainty. The effect of dry deposition of SVOC on the concentration of secondary organic aerosols (SOA) is investigated in summertime with the chemical transport model CHIMERE that simulates SOA concentrations by means of molecular SOA surrogate species. Omitting dry deposition could overestimate SOA concentrations by as much as 50%. This overestimation is larger during nighttime due to higher relative humidity.  相似文献   
7.
Cyclic volatile methyl siloxanes (cVMS) are high volume production chemicals used in a wide range of industrial and consumer products. Three cVMS compounds (D4, D5, and D6) have and are undergoing environmental risk evaluations in several countries and have been proposed for legal regulation in Canada. As interest in monitoring concentrations of these chemicals in the environment increase, there is a need to evaluate the analytical procedures for cVMS in biological matrices in order to assess the quality of data produced. The purpose of this study was to determine laboratory testing performance for measuring residues of D4, D5, and D6 in a standard set of fish homogenate samples and to estimate limits of determination for each substance. The samples sent to each laboratory consisted of homogenized whole body tissues of hatchery raised rainbow trout which were fed food fortified with D4, D5, and D6 (dosed) and trout that were fed standard food rations (control). The participants analyzed each sample using their analytical method of choice using their own standards and procedures for quantification and quality control. With a few exceptions, participating laboratories generated comparable results for D4, D5, and D6 in both the dosed and control samples having z-scores between 2 and −2. Method detection limits for the whole fish matrix were on average 2.4 ng g−1 ww for D4, 2.3 ng g−1 ww for D5, and 1.8 ng g−1 ww for D6.  相似文献   
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Various analyses of an asphaltenic fraction of Asthart crude oil enabled us to show that it was partially degraded by a marine mixed bacterial population with saturated hydrocarbons as cosubstrate. We also gave evidence of its strong biotransformation rate and tried to correlate its evolution with the nature of the produced fractions.  相似文献   
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