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Duchenne and Becker muscular dystrophy (D/BMD) are usually problematical when trying to determine the carrier status of at-risk women, which usually has to be based on haplotype or dosage analysis on Southern blots. Using multiplex polymerase chain reaction (PCR) analysis, we have detected deletions in 20 out of 44 D/BMD families with living affected members (45·5 per cent), more often in sporadic cases of DMD (14/22 with detectable deletion) than in familial ones (4/15), the majority (15/20) occurring in the distal region of the D/BMD gene. Four highly informative short tandem repeat polymorphisms (STRPs), which lie within the distal deletion hot spot of the D/BMD gene, can show loss of heterozygosity in carrier females, providing direct evidence of their carrier status. These STRPs greatly improve informativity, with a combined heterozygosity of 100 per cent and with the majority of families informative for three of the four STRPs. In 14/15 (93 per cent) of the families with distal deletions, the STRPs provided direct information on carrier status, and in some cases, they provide valuable information on recombination breakpoints and non-paternity.  相似文献   
124.
The exposure of paving workers to polycyclic aromatic hydrocarbons (PAH) during stone mastic asphalt (SMA) paving and remixing was evaluated. The effects on the workers' PAH exposure were also evaluated during the use of an industrial by-product, coal fly ash (CFA), instead of limestone as the filler in the SMA. The PAH exposure was measured by personal air sampling and by analysing the levels of urinary naphthols, phenanthrols and 1-hydroxypyrene (1-OHP) in the workers' pre- and post-shift urine samples. The respiratory PAH exposure of the paving workers (geometric mean (GM) 5.7 microg m(-3)) was about ten-fold that of the traffic controllers (GM 0.43 microg m(-3)). The levels of PAH metabolites were significantly higher (p < 0.05) in the post-shift urine samples than in the pre-shift urine samples, and the levels of metabolites in the post-shift urine of paving workers were significantly higher than in that of the controls (p < 0.01). Urinary 1-naphthol correlated well with the airborne concentrations of the two- to three-ring PAHs (r = 0.544, p = 0.003) and naphthalene (r = 0.655, p < 0.001), when non-smoking paving workers were tested. A good correlation was observed between urinary 1-OHP and the airborne concentrations of the four- to six-ring PAHs (r = 0.524, p = 0.003) as well as total PAHs (r = 0.575, p = 0.001). The concentrations of 1-OHP and phenanthrols in the urine of the pavers were significantly higher (p < 0.01) during remixing than during SMA paving. The CFA in the asphalt had no effect on the airborne PAH exposure or on the concentrations of the PAH metabolites in the paving workers' urine.  相似文献   
125.
Forests cover approximately one‐third of Central Europe. Oak (Quercus) and European beech (Fagus sylvatica) are considered the natural dominants at low and middle elevations, respectively. Many coniferous forests (especially of Picea abies) occur primarily at midelevations, but these are thought to have resulted from forestry plantations planted over the past 200 years. Nature conservation and forestry policy seek to promote broadleaved trees over conifers. However, there are discrepancies between conservation guidelines (included in Natura 2000) and historical and palaeoecological data with regard to the distribution of conifers. Our aim was to bring new evidence to the debate on the conservation of conifers versus broadleaved trees at midelevations in Central Europe. We created a vegetation and land‐cover model based on pollen data for a highland area of 11,300 km2 in the Czech Republic and assessed tree species composition in the forests before the onset of modern forestry based on 18th‐century archival sources. Conifers dominated the study region throughout the entire Holocene (approximately 40–60% of the area). Broadleaved trees were present in a much smaller area than envisaged by current ideas of natural vegetation. Rather than casting doubt on the principles of Central European nature conservation in general, our results highlight the necessity of detailed regional investigations and the importance of historical data in challenging established notions on the natural distribution of tree species.  相似文献   
126.
The objective of this study was to evaluate the performance of handheld XRF analyzers on wood that has been treated with a preservative containing arsenic. Experiments were designed to evaluate precision, detection limit, effective depth of analysis, and accuracy of the XRF arsenic readings. Results showed that the precision of the XRF improved with increased sample concentration and longer analysis times. Reported detection limits decreased with longer analysis times to values of less than 1mg/kg or 18 mg/kg, depending on the model used. The effective depth of analysis was within the top 1.2 cm and 2.0 cm of sample for wood containing natural gradients of chemical preservative and concentration extremes, respectively. XRF results were found to be 1.5-2.3 times higher than measurements from traditional laboratory analysis. Equations can be developed to convert XRF values to results which are consistent with traditional laboratory testing.  相似文献   
127.
The release of heavy metals into the environment, mainly as a consequence of anthropogenic activities, constitutes a worldwide environmental pollution problem. Unlike organic pollutants, heavy metals are not degraded and remain indefinitely in the ecosystem, which poses a different kind of challenge for remediation. It seems that the “best treatment technologies” available may not be completely effective for metal removal or can be expensive; therefore, new methodologies have been proposed for the detoxification of metal-bearing wastewaters. The present work reviews and discusses the advantages of using brewing yeast cells of Saccharomyces cerevisiae in the detoxification of effluents containing heavy metals. The current knowledge of the mechanisms of metal removal by yeast biomass is presented. The use of live or dead biomass and the influence of biomass inactivation on the metal accumulation characteristics are outlined. The role of chemical speciation for predicting and optimising the efficiency of metal removal is highlighted. The problem of biomass separation, after treatment of the effluents, and the use of flocculent characteristics, as an alternative process of cell–liquid separation, are also discussed. The use of yeast cells in the treatment of real effluents to bridge the gap between fundamental and applied studies is presented and updated. The convenient management of the contaminated biomass and the advantages of the selective recovery of heavy metals in the development of a closed cycle without residues (green technology) are critically reviewed.  相似文献   
128.
The reduction of organic and nitrogen pollution of wastewater was investigated in two hybrid reactors and compared with the reduction obtained by using a conventional activated sludge reactor (ASR) run as a control. Both HR-1 and HR-2 were activated sludge systems where a low-density carrier, P1 (polyethylene) for HR-1 and P2 (recycled plastics) for HR-2, was added. Firstly, the three reactors were operated at 10 days Suspended Solid Retention Time (SRT(SS)), leading to a complete nitrification. Secondly, the SRT(SS) for each reactor was lowered to 3 days. Nitrification was lost for the ASR but remained complete for HR's. Respirometric techniques were used to measure fixed or suspended biomass activities for heterotrophic and autotrophic biomass. More than 90% of the autotrophic activity was found on the supports whatever the SRT(SS) used. The results may underline the role of the carrier geometry or surface characteristics on the autotrophic/heterotrophic microorganism distribution.  相似文献   
129.
Methylation of mercury (Hg) to highly toxic methyl Hg (MeHg), a process known to occur when organic matter (OM) decomposition leads to anoxia, is considered a worldwide threat to aquatic ecosystems and human health. We measured temporal and spatial variations in sediment MeHg, total Hg (THg), and major elements in a freshwater lagoon in Sweden polluted with Hg-laden cellulose fibers. Fiber decomposition, confined to a narrow surface layer, resulted in loss of carbon (C), uptake of nitrogen (N), phosphorus (P), and sulfur (S), and increased MeHg levels. Notably, fiber decomposition and subsequent erosion of fiber residues will cause buried contaminants to gradually come closer to the sediment–water interface. At an adjacent site where decomposed fiber accumulated, there was a gain in C and a loss of S when MeHg increased. As evidenced by correlation patterns and vertical chemical profiles, reduced S may have fueled C-fixation and Hg methylation at this site.  相似文献   
130.
Aim of the study was to monitor changes of genotoxic activity of urban air caused by an incinerator and a petrochemical plant in Tradescantia micronucleus (Trad-MCN) and pollen fertility assays with wild plants (Chelidonium majus, Clematis vitalba, Cichorium intybus, Linaria vulgaris, Robinia pseudoacacia). While in the first sampling period (1997-2000) significantly (on average 80%) more MN were found at the polluted site in comparison to controls from a rural area, no significant effects were observed during a later period (between 2003 and 2005). A similar pattern was observed in the pollen abortion assays in which the most pronounced effects were found in chicory and false acacia. The differences of the results obtained in the two periods can be explained by a substantial reduction of air pollution by use of new technologies. In particular the decrease of SO(2) emissions may account for the effects seen in the present study.  相似文献   
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