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171.
Abstract

The in vitro enzyme activity of head homogenates of Coccinella septempunctata from different habitats (wheat, barley, rye and set‐aside fields in Belgium and Hungary) and the effect of in vivo surface contact treatments with organophosphorous active ingredients on the same species were investigated. The in vitro studies indicated that the acetylcholinesterase (AChE) of C. septempunctata was less sensitive to inhibition by paraoxon than by malaoxon in the case of each population. The differences found between parathion and malathion treatments in in vivo testing were not significant. The inhibition process of paraoxon suggests that the seven‐spot ladybird may have at least two AChEs responding differently for the paraoxon inhibition.  相似文献   
172.
Mechanical friction and impacts is still today a main cause of ignition of explosive atmospheres (ATEX) in the industry and this trend seems to be stable in time. This situation certainly results from a significant gap of knowledge in the underlying mechanisms so that the parameters to play on are not precisely identified. In this programme of European dimensions, the process of degradation of the mechanical energy into heat during friction and impacts have been studied.

An extensive experimental programme is presented to this end. The mechanisms of dissipation of the mechanical energy into heat during friction has been studied with rubbing machines in which a slider equipped with temperature sensors rubs against a rotating wheel. For impacts, a new device has been developed using a special “air driven cannon” to propel a projectile accurately up to 50 m/s onto an inclined target. A very significant effort has been reserved to the investigation of the ignition mechanisms, not only for ATEX but also for dust accumulations.

Some “simple” modelling is proposed on purpose of practical applications. For frictional situations, a critical rubbing power is calculated without any limitations about any lower boundary concerning the rubbing velocity. For “impacts”, the relevant parameter for ignition is not the kinetic energy of the projectile but its velocity and the nature of the materials.  相似文献   

173.
174.
In a retrospective analysis of 28 cases of fetal diaphragmatic hernia, overall mortality was 86 per cent, but fell to 70 per cent when multiple anomalies were excluded. Congenital heart disease constituted the majority of associated anomalies. The incidence of an abnormal karyotype was 10·5 per cent, but rose to 20 per cent when only fetuses with multiple anomalies were included. Polyhydramnios, which occurred in 75 per cent, was a poor predictor of fetal outcome. The same applied to the intrathoracic position of the fetal stomach. In all four survivors, diaphragmatic hernia was diagnosed beyond 32 weeks of gestation.  相似文献   
175.
The reuse of wastewater for irrigation of agricultural land is a well established practice but introduces many contaminants into the terrestrial environment including pharmaceuticals and personal care products. This study reports the persistence and leaching potential of a group of acidic pharmaceuticals, carbamazepine, and three endocrine disruptors in soils from the Tula Valley in Mexico, one of the largest irrigation districts in the world that uses untreated wastewater. After irrigation of soil columns with fortified wastewater over the equivalent of one crop cycle, between 0% and 7% of the total added amounts of ibuprofen, naproxen, and diclofenac and between 0% and 25% of 4-nonylphenol, triclosan, and bisphenol-A were recovered from the soil profiles. Carbamazepine was more persistent, between 55% and 107% being recovered. Amounts in leachates suggested that movement through the soil was possible for all of the analytes, particularly in profiles of low organic matter and clay content. Analysis of soil samples from the Tula Valley confirmed the general lack of accumulation of the acidic pharmaceuticals (concentrations from below the limit of detection to 0.61 μgkg(-1)) and endocrine disruptors (concentrations from below the limit of detection to 109 μgkg(-1)) despite continual addition through regular irrigation with untreated wastewater; there was little evidence of movement through the soil profiles. In contrast, carbamazepine was present in horizon A of the soil at concentrations equivalent to several years of additions by irrigation (2.6-7.5 μgkg(-1)) and was also present in the deeper horizons. The persistence and mobility of carbamazepine suggested a potential to contaminate groundwater.  相似文献   
176.
A novel microbiological mutagenicity assay, based on bioluminescence of a marine bacterium Vibrio harveyi mutant strain, potentially suitable for monitoring and assessment of mutagenic pollution of marine environment, has been described recently. Here, we tested the use of this assay, in combination with either mussels (Mytilus sp.) or semipermeable membrane devices (SPMDs), in assessment of accumulation of mutagens in marine water (samples of Baltic Sea water were tested). Either similar results were obtained in both systems or higher signals in the SPMD-based system were detected, depending on the tested water samples. We conclude that the use of both mussels and SPMDs in combination with the V. harveyi bioluminescence mutagenicity assay is a method suitable for monitoring and assessment of accumulation of mutagenic pollutants in marine environment, but in some cases the SPMD-based system may provide a more sensitive test.  相似文献   
177.
178.
Several on-site studies have been conducted on rock formations and soils where gases were collected into boreholes. The equipment consisted of packers isolating a chamber for gas collection. A pump allows gas transfer towards FT-IR sensors located at the surface. Such analytical approach shows several advantages for gas monitoring in boreholes: it allows variation detection with time of the partial pressure of gases; detection and evolution with time of the concentration of annex gases or markers; application to the injection and post-injection periods to determine possible deviations from a previously recorded baseline; and possible use of several boreholes in networks.  相似文献   
179.
180.
Journal of Material Cycles and Waste Management - The aim of this study was to analyze the efficiency of a system of treatment of organic swine waste as a management tool in the transformation of...  相似文献   
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