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991.
A rapid, sensitive, accurate and reliable multiresidue method for the identification and quantification of 210 relevant pesticides in four representative fruit and vegetable commodities (tomato, potato, spring onion and orange) has been developed and validated by gas chromatography in tandem with triple quadrupole mass spectrometry. The method has been fully validated and applied to 292 samples from different countries. Prior to instrumental analysis, an extraction procedure based on a sample extraction of multiclass analytes, using the ethyl acetate method was employed. Mass spectrometric conditions were individually optimized for each compound in the selected reaction monitoring (SRM) mode to achieve maximum sensitivity. The pesticides were separated in less than 25 min. This was followed by an exhaustive control of the retention times. The Retention Time Locking Method was applied, working at a constant pressure throughout the analysis. System maintenance was reduced by using a purged capillary flow device that provided backflush capabilities by reversing column flow immediately after elution of the last compound of interest. Istotopically labelled internal standards were employed to improve the quality of the analytical results.  相似文献   
992.

Objective

Recent studies have integrated copy number variant (CNV) and gene analysis using target enrichment. Here, we transferred this concept to our routine genetics laboratory, which is not linked to centralized non-invasive prenatal testing (NIPT) facilities.

Method

From a cohort of 100 pregnant women, 22 were selected for the analysis of maternal genomic DNA (gDNA) along with fetal cell-free DNA. Using targeted enrichment, 135 genes were analyzed, combined with aberrations of chromosomes 21, 18, 13, X, and Y. The data were subjected to specificity and sensitivity analyses, and correlated with the results from invasive testing methods.

Results

The sensitivity/specificity was determined for the CNV analysis of chromosomes: 21 (80%/75%), 18 (-/82%), 13 (100%/67%), and Y (100%/100%). The gene detection was valid for maternal gDNA. However, for cell-free fetal DNA, it was not possible to determine the boundary between an artifact and a real sequence variant.

Conclusion

The target enrichment method combining CNV and gene detection seems feasible in a regular laboratory. However, this method can only be responsibly optimized with a sufficient number of controls and further validation on a strong bioinformatic background. The present results showed that NIPT should be performed in specialized centers, and that its introduction to isolated laboratories may not provide valid data.  相似文献   
993.
Three different sorbents based on hydrated ferric oxide (GEH, ArsenXnp and Lewatit FO 36) were compared from the viewpoints of their column operation. Particle size distribution, pressure drop across the column and ferric oxide content were measured. Sorption capacities under the presence of accompanying ions were measured in batch wise and column experiments.  相似文献   
994.
In this study we observed the production of volatile fatty acids (VFAs) during the composting process of compost heaps in two different bioreactors (open and closed) at three different depths (0, 40 and 80 cm). The compost was prepared as a mixture of bio-waste, horse manure, grass and sawdust to ensure sufficient pH conditions in compost heaps. VFA contents in the composting materials were analysed weekly over 14–119 d. The degradation process was monitored, along with temperature, pH, total organic carbon, oxidizable carbon and mono- and oligosaccharides. VFA contents were evaluated with regard to the depth of the sample site in the compost heap and to conditions in the bioreactors. The maximum VFA occurrence was observed during the first 35 d; acetic and propionic acids in particular were determined to occur in each sample. Considerable variations in their formation and elimination were observed in the two bioreactors as well as at the various depths in the compost heaps. Significant correlations were found between individual VFAs, as well as between VFA concentrations and organic carbon contents.  相似文献   
995.
With the worldwide intensification of agriculture, non-point source pollution of surface waters has become a pressing issue. Conventional river water quality models consider non-point sources as accumulated entries into the rivers and do not investigate into the processes generating the pollution at its source, thus preventing the determination of effective mitigation measures. The models require extensive data inputs, which is a deficiency in many developing and emerging countries with limited data availability. The current study applies a Material Flow Model as a complementary approach to quantify non-point source pollution from agricultural areas. Rice farming in the Thachin River Basin is presented as a case study, with a focus on nutrients. The total nitrogen and phosphorus flows from rice farming to the river system are quantified, the key parameters influencing these flows are determined and potential mitigation measures are discussed. The results show that rice contributes considerable nutrient loads to the Thachin River Basin. Scenario simulations demonstrate that a significant nutrient load reduction could be achieved by following the official recommendations for fertilizer application, thus confirming the local efforts to introduce best management practice. Our results underline the importance of non-point source pollution control in intensive agricultural areas, particularly of tropical lowland delta areas such as the Central Plains of Thailand. The specific benefit of applying a Material Flow Model in this context is that with limited data availability, one can reach an understanding of the system and gain a first overview over its key pollution problems. This can serve as supportive basis for determining consecutive in-depth research requirements.  相似文献   
996.
Biologically based wastewater treatment systems are considered a sustainable, cost-effective alternative to conventional wastewater treatment systems. These systems have been used and studied for the treatment of urban sewage from small communities, and recently, it has been reported that they can also effectively remove emerging organic contaminants (EOCs). EOCs are a new group of unregulated contaminants which include pharmaceutical and personal care products, some pesticides, veterinary products, and industrial compounds among others that are thought to have long-term adverse effects on human health and ecosystems. This review is focused on reporting the ability of biologically based wastewater treatment systems to remove EOCs and the main elimination mechanisms and degradation processes (i.e., biodegradation, photodegradation, phytoremediation, and sorption) taking place in constructed wetlands, ponds, and Daphnia and fungal reactors.  相似文献   
997.
基于徐州台和常熟台 2 套 VP 型宽频带倾斜仪记录到的 186 次同震形变波,统计分析其振幅-震级特征,分区对比研究其衰减关系,结合观测资料计算仪器特征参数,通过岩芯试验获取场地基岩性质,综合分析仪器观测效能。结果表明:(1)相比于常熟台,徐州台的 NS 向和 EW 向拟合均较为稳定,记震能力更好;(2)不同构造分区中拟合的振幅-震级关系,随着震中距增大,最大振幅幅值呈指数上升且拟合程度显著增强;(3)仪器基墩稳定性对同震响应存在一定的影响,基墩稳定性好,观测数据年零漂小,同震记录相对稳定;不同岩性的基墩对同震记录的敏感性存在差异,同震响应振幅与基墩弹性模量成反比。  相似文献   
998.
Contemporary reports on the energy and environmental benefits of bioethanol have suggested that the cellulosic ethanol is significantly more efficient. To understand the development potential of energy crops in Taiwan, the present study has assessed the resources and cost inputs for the planning, harvesting, transporting, and storing procedures of the first generation energy crops during 2007–2010 with the perspective of LCA. In addition, a field investigation focusing on rice straw, the largest agricultural waste in Taiwan, has been conducted since 2010 to obtain fundamental data.This study further analyzes the first and second-generation feedstocks from the perspective of LCA based on field investigated data. Taiwan has not yet established an ethanol plant; therefore, this study established production data by simulating the production efficiency of an economical scale using parameters obtained through production trials, and proposed an evaluation model for the energy input, GHG, and production costs of bioethanol in Taiwan. The results of this study were cross-compared with foreign literature to explore the development potential of bioethanol in Taiwan. The results indicate that based on the current cellulosic ethanol technology in Taiwan, regarding the energy balance, GHG, and production costs, is less efficient than that of the first generation bioethanol.  相似文献   
999.
New approaches to forest planning are needed to support the transition of European forests to sustainable management. The aim of this study is to review forest planning systems already in place throughout Europe by exploring a set of case-study countries reflecting the main silvicultural schools of Western Europe, including Belgium, Finland, France, Italy, Portugal, and Slovenia.

A literature review and case-study data were used to assess the scale factors (vertical logic) as well as the relationships between forest planning and other environmental/land-use planning sectors (horizontal logic). The influence of EU policy on the development of forest planning is also discussed. As assessed using the vertical logic, the multi-scale and multi-topic planning approaches adopted in the countries studied here are highly heterogeneous. The horizontal logic shows that despite the importance of an inter-sectoral and harmonic relational framework between forest planning and the planning efforts of other sectors such as landscape and urban planning, the various plans are barely consistent with each other across the European countries studied here. Although interest is growing in the multi-functionality of forests, their sustainable management calls for the development of better integrated planning approaches across Europe.  相似文献   

1000.
作为一种曾经广泛使用的氯化烃杀虫剂,DDT及其主要代谢产物DDE和DDD(合称为DDTs)是一类典型的具有持久性和生物累积性的有毒污染物。亲脂性和持久性使得DDTs可以通过食物链进行生物放大,从而对处于高营养级的水生哺乳动物造成严重的毒害作用。在综述DDTs对哺乳动物的毒性研究基础上,采用物种敏感度分布(species sensitivity distribution,SSD)和毒性百分数排序法(toxicity percentile rank method,TPRM)推导DDTs保护水生哺乳动物的组织残留基准(Tissue Residue Guideline,TRG)。使用SSD和TPRM得到的TRG分别为23.9和22.7 ng·g-1食物(湿重)。相应的,DDTs保护水生哺乳动物的水质基准分别为188.2和178.7 pg·L-1。依据研究得到的DDTs的组织残留基准及其在鱼类体内的含量评估对水生哺乳动物的风险。研究结果可用于评估DDTs对水生哺乳动物的生态风险,并为DDTs的风险管理提供理论依据。  相似文献   
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