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671.
Prenatal diagnosis choices were reviewed in 473 women who presented for genetic counselling prior to 11 weeks' gestation for the indication of advanced maternal age. Group A consisted of 336 patients who were unaware of a possible association between chorionic villus sampling (CVS) and limb defects. Group B consisted of 137 patients who were provided this information. Fifty-one per cent of patients in group A and 45 per cent of patients in group B chose CVS. This difference was not significant by χ2 analysis (P = 0·7). Patterns of prenatal diagnosis procedure utilization from 1987 to 1992 revealed a significant reduction in CVS utilization accompanied by a corresponding increase in amniocentesis after the association between CVS and limb defects was publicized. Referrals for CVS counselling also significantly declined. However, acceptance rates did not change for those patients who received genetic counselling. First-trimester genetic counselling, including a discussion regarding a possible association between CVS and limb defects, helps patients make informed decisions concerning prenatal diagnosis options, and, in our population, resulted in no change in CVS acceptance rates.  相似文献   
672.
From feathers to syngas - technologies and devices   总被引:1,自引:0,他引:1  
The poultry waste produced by industrial slaughterhouses typically contains not only feathers, but also a mixture of animal entrails, nails, blood, beaks and whole carcasses. Economical utilisation of this mixture, varying strongly in composition and moisture content, is, in general, difficult. We demonstrate that this awkward material can be successfully used for gasification in a simple, fixed-bed gasifier. The method of gasification, which we developed, enables control of the gasification process and ensures its stability in the operational regime of a working poultry processing plant. The installation, which has been working in Poland for 2 years, utilises 2 tons of feathers per hour and produces syngas of stable composition and fairly high quality. The syngas is burnt in the combustion chamber adjacent to the gasifier. Heat is recuperated in a boiler producing 3.5 tons per hour of technological steam continuously used for the operation of the slaughterhouse. The whole process complies with the stringent emission standards. In the paper we present the end-use device for feather utilisation and describe the underlying gasification and syngas combustion processes. Key elements of the whole installation are briefly discussed. The environmental impacts of the installation are summarized.  相似文献   
673.
Abstract

This paper summarizes information on the spatial and temporal variability of selected air toxics pollutants collected on a national basis primarily for a period encompassing 1990–2003. Spatial information on pollutant concentrations is characterized in terms of within-city and between-city variability. Temporal information is summarized as diurnal and seasonal variability and in multiyear trends. The information on variability is presented in the framework of a larger need for systematic documentation of information on air toxics pollutants to assess progress in air pollution control programs.  相似文献   
674.
In this study, we have examined the effects of synthetic medium ingredients and culture incubation conditions on growth and tributyltin chloride (TBT) degradation activity of the fungus Cunninghamella elegans. The best efficiency of TBT conversion to less toxic derivatives: dibutyltin and monobutyltin was noticed on media which contained glucose, NH(4)Cl, K(2)HPO(4) and MgSO(4). Next, the constructed M3 medium (with the above components) ensured vigorous growth of C. elegans and allowed the reduction of 80% of the initial TBT content (10 mg l(-1)), after 3d of biodegradation. The further acceleration of the biocide utilization by C. elegans was achieved by additional oxygen supply (pO(2) >or = 20%) to the growing fungus (89% after 2d of incubation in the BioFlo II bioreactor). The efficient xenobiotic biodegradation was related to the intensity of fungal growth. The obtained results suggest a cometabolic nature of TBT utilization by C. elegans.  相似文献   
675.
This paper presents the analysis of ambient air concentrations of 10 carbonyl compounds (aldehydes and ketones) measured in the yards of 87 residences in the city of Elizabeth, NJ, throughout 1999-2001. Most of these residences were measured twice in different seasons; the sampling duration was 48 hr each time. The authors observed higher concentrations for most of the measured carbonyl compounds on warmer days, reflecting larger contributions of photochemical reactions on warmer days. The estimated contributions of photochemical production varied substantially across the measured carbonyl compounds and could be as high as 60%. Photochemical activity, however, resulted in a net loss for formaldehyde. The authors used stepwise multiple linear regression models to evaluate the impact of traffic sources and meteorological conditions on carbonyl concentrations using the data collected on colder days (with lower photochemical activities). They found that the concentrations of formaldehyde, acetaldehyde, acrolein, propionaldehyde, crotonaldehyde, benzaldehyde, glyoxal, and methylglyoxal significantly decreased with increasing distance between a measured residence and one or more major roadways. They also found significant negative associations between concentrations for most of the measured carbonyl compounds and each of the following meteorological parameters: mixing height, wind speed, and precipitation.  相似文献   
676.
We studied the effect of chlorfenvinphos dermal absorption on the morphological picture of blood, on the histological and fine structure of tail skin, and on the histological structure of internal organs (lungs, heart, liver, spleen, and kidney) of rats. This study was conducted on 25 white Wistar rats, the tail skin of which was—or was not—hydrated before exposure. Rat tails were soaked in 0.5% or 0.05% chlorfenvinphos for 1 hr day for 3 months. Evident tendencies for a decrease in the absolute level of leukocytes and for an increase in the absolute level of erythrocytes in all experimental animals were observed. Histopathological changes in the internal organs were mildly manifested in only a few rats, mainly as liver and pulmonary hyperaemia. Rat tail skin at the direct exposure site showed hyperceratosis, intensive desquamation, and compensatory hyperplasia.  相似文献   
677.
A series of six large scale high pressure jet fires were conducted using natural gas and natural gas/hydrogen mixtures. Three tests involved natural gas and three involved a mixture of natural gas and hydrogen containing approximately 24% by volume hydrogen. For each fuel, the three tests involved horizontal releases from 20, 35 and 50 mm diameter holes at a gauge pressure of approximately 60 bar. During the experiments, the flame length and the incident radiation field produced around the fire were measured. The fires also engulfed a 1 m diameter horizontal pipe placed across the flow direction and about halfway along the flame. This pipe was instrumented to measure the heat fluxes to the pipe. The data obtained is compared with previous data obtained for various hydrocarbons at large scale.  相似文献   
678.
The aim of this study was to assess handgrip and 5 other types of force in 52 women and to determine if handgrip force reflected general upper limb force capabilities correlated with age. The women were divided into subgroups according to age: 20-25, 45-50 and 55-65 years. Maximum forces of the right upper limb were measured in 6 types of force activities. In most tests the values of force showed statistically significant differences between the 20-25 group and the groups aged 45-50 and 55-64 years. The results did not show any differences related to age or to force activities that involved the small muscles of the forearms and hands. Thus handgrip force cannot always be considered an indicator of total force capabilities.  相似文献   
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