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641.
Novel bio-based green films were prepared using wheat protein isolate (WPI) by solution casting method using Propylene Glycol as a plasticizer for packaging applications. The effect of the plasticizer content (10, 15, 20 and 25 wt%) on mechanical properties (tensile strength, young’s modulus and  % of elongation) was investigated. A thermal degradation and phase transition of the prepared WPI was assessed by means of TGA and DSC analysis. The results showed that the tensile strength and young’s modulus decreased and  % of elongation increased with increasing PG content. The ATR-FTIR and SEM were used for structural characterization and morphology of the films, respectively. FTIR studies reveals that the intensity of the bands corresponding to the amide groups increases with increasing PG content tending to increase protein–PG interactions. Further, the glass transition temperature was decreased and the thermal stability of the WPI was found to be increased by plasticization. The overall thermal stability of the films was improved and is attributed to the increase in mobility of the polymer chains.  相似文献   
642.
The objective was to describe and model variation patterns in individual fish responses to contaminants among estuaries, season and gender. Two hundred twenty-seven adult European flounders were collected in two seasons (winter and summer) in four estuaries along the Bay of Biscay (South West France), focusing on a pristine system (the Ster), vs. three estuaries displaying contrasted levels of contaminants (the Vilaine, Loire and Gironde). Twenty-three variables were measured by fish, considering the load of contaminants (liver metals, liver and muscle persistent organic pollutants, muscle polycyclic aromatic hydrocarbons); the gene expression (Cyt C oxydase, ATPase, BHMT, Cyt P450 1A1, ferritin); the blood genotoxicity (Comet test); and liver histology (foci of cellular alteration–tumour, steatosis, inflammation, abnormal glycogen storage). Canonical redundancy analysis (RDA) was used to model these variables using gender, season and estuary of origin as explanatory variables. The results underlined the homogeneity of fish responses within the pristine site (Ster) and more important seasonal variability within the three contaminated systems. The complete model RDA was significant and explained 35 % of total variance. Estuary and season respectively explained 30 and 5 % of the total independent variation components, whilst gender was not a significant factor. The first axis of the RDA explains nearly 27 % of the total variance and mostly represents a gradient of contamination. The links between the load of contaminants, the expression of several genes and the biomarkers were analysed considering different levels of chemical stress and a possible multi-stress, particularly in the Vilaine estuary.  相似文献   
643.
Meta-analysis of environmental contamination by phthalates   总被引:1,自引:0,他引:1  
Phthalate acid esters (PAE), commonly named phthalates, are toxics classified as endocrine-disrupting compounds; they are primarily used as additives to improve the flexibility in polyvinyl chloride. Many studies have reported the occurrence of phthalates in different environmental matrices; however, none of these studies has yet established a complete overview for those compounds in the water cycle within an urban environment. This review summarizes PAE concentrations for all environmental media throughout the water cycle, from atmosphere to receiving waters. Once the occurrences of compounds have been evaluated for each environmental compartment (urban wastewater, wastewater treatment plants, atmosphere, and the natural environment), we reviewed data in order to identify the fate of PAE in the environment and establish whether geographical and historical trends exist. Indeed, geographical and historical trends appear between Europe and other countries such as USA/Canada and China, however they remain location dependent. This study aimed at identifying both the correlations existing between environmental compartments and the processes influencing the fate and transport of these contaminants into the environment. In Europe, the concentrations measured in waterways today represent the background level of contamination, which provides evidence of a past diffuse pollution. In contrast, an increasing trend has actually been observed for developing countries, especially for China.  相似文献   
644.
Debate and literature on the link between degrading environments and human mobility has been increasing exponentially. There is little concrete evidence, however, of efforts or policies that support the management of environmentally influenced mobility. Through discourse analysis using Q-methodology, this research aimed to scrutinize the standoff between opposing views under a fresh lens. One-hundred and ninety-seven experts from 49 nations completed an on-line survey asking them to sort, by level of agreement, 42 statements gleaned from the literature concerning the environment-mobility nexus. Four very different discourses emerged: determined humanists, benevolent pragmatists, cynical protectionists, and critical realists. The complexity of these discourses helps explain the stalemate while confirming the inappropriateness of one-sided terminology and linear quantifications. Despite diametrically opposed viewpoints, experts unanimously agree that human mobility is connected to environmental change. Dissection of these social perspectives builds a new foundation for the Rio+20 analysis and policy deliberations related to environmentally influenced human mobility.  相似文献   
645.
Water samples from streams, brooks and storm sewer outfall pipes that collect storm waters across the Island of Montréal were analyzed for caffeine, carbamazepine and fecal coliforms. All samples contained various concentrations of these tracers, indicating a widespread sanitary contamination in urban environments. Fecal coliforms and caffeine levels ranged over several orders of magnitude with a modest correlation between caffeine and fecal coliforms (R2 value of 0.558). An arbitrary threshold of 400 ng caffeine L−1 allows us to identify samples with an elevated fecal contamination, as defined by more than 200 colony-forming units per 100 mL (cfu 100 mL−1) of fecal coliforms. Low caffeine levels were sporadically related to high fecal coliform counts. Lower levels of caffeine and fecal coliforms were observed in the brooks while the larger streams and storm water discharge points contained over ten times more. The carbamazepine data showed little or no apparent correlation to caffeine. These data suggest that this storm water collection system, located in a highly urbanized urban environment, is widely contaminated by domestic sewers as indicated by the ubiquitous presence of fecal contaminants as well as caffeine and carbamazepine. Caffeine concentrations were relatively well correlated to fecal coliforms, and could potentially be used as a chemical indicator of the level of contamination by sanitary sources. The carbamazepine data was not significantly correlated to fecal coliforms and of little use in this dataset.  相似文献   
646.
In the context of the Water Framework Directive (EP and CEU, 2000), management plans have to be set up to monitor and to maintain water quality in groundwater bodies in the EU. In heavily industrialized and urbanized areas, the cumulative effect of multiple contaminant sources is likely and has to be evaluated. In order to propose adequate measures, the calculated risk should be based on criteria reflecting the risk of groundwater quality deterioration, in a cumulative manner and at the scale of the entire groundwater body. An integrated GIS- and flux-based risk assessment approach for groundwater bodies is described, with a regional scale indicator for evaluating the quality status of the groundwater body. It is based on the SEQ-ESO currently used in the Walloon Region of Belgium which defines, for different water uses and for a detailed list of groundwater contaminants, a set of threshold values reflecting the levels of water quality and degradation with respect to each contaminant. The methodology is illustrated with first results at a regional scale on a groundwater body-scale application to a contaminated alluvial aquifer which has been classified to be at risk of not reaching a good quality status by 2015. These first results show that contaminants resulting from old industrial activities in that area are likely to contribute significantly to the degradation of groundwater quality. However, further investigations are required on the evaluation of the actual polluting pressures before any definitive conclusion be established.  相似文献   
647.
Biodiversity conservation decisions are difficult, especially when they involve differing values, complex multidimensional objectives, scarce resources, urgency, and considerable uncertainty. Decision science embodies a theory about how to make difficult decisions and an extensive array of frameworks and tools that make that theory practical. We sought to improve conceptual clarity and practical application of decision science to help decision makers apply decision science to conservation problems. We addressed barriers to the uptake of decision science, including a lack of training and awareness of decision science; confusion over common terminology and which tools and frameworks to apply; and the mistaken impression that applying decision science must be time consuming, expensive, and complex. To aid in navigating the extensive and disparate decision science literature, we clarify meaning of common terms: decision science, decision theory, decision analysis, structured decision-making, and decision-support tools. Applying decision science does not have to be complex or time consuming; rather, it begins with knowing how to think through the components of a decision utilizing decision analysis (i.e., define the problem, elicit objectives, develop alternatives, estimate consequences, and perform trade-offs). This is best achieved by applying a rapid-prototyping approach. At each step, decision-support tools can provide additional insight and clarity, whereas decision-support frameworks (e.g., priority threat management and systematic conservation planning) can aid navigation of multiple steps of a decision analysis for particular contexts. We summarize key decision-support frameworks and tools and describe to which step of a decision analysis, and to which contexts, each is most useful to apply. Our introduction to decision science will aid in contextualizing current approaches and new developments, and help decision makers begin to apply decision science to conservation problems.  相似文献   
648.
通过离子选择电极法测定Fe3+和Al3+不同含量的土壤样品中水溶性氟化物试验,研究Fe3+和Al3+对测定的干扰与消除方法,证实了在总离子强度调节缓冲溶液共存下,Fe3+和Al3+对土壤提取液中水溶性氟化物检测结果存在不同程度的负干扰。选择6种代表性土壤样品,在水溶性氟化物提取液中加入20 mg/L的Al3+和100 mg/L的Fe3+做干扰试验,比较了分取不同体积土壤提取液对氟化物检测结果的影响,结果表明,对水溶性ρ(Fe3+)和ρ(Al3+)高的土壤样品,可选择减少提取液取样体积来消除干扰。选取的5种标准样品测试结果与标准值相符,干扰消除方法具有良好的适用性。  相似文献   
649.
The Biological Resource Centre for the Environment BRC4Env is a network of Biological Resource Centres (BRCs) and collections whose leading objectives are to improve the visibility of genetic and biological resources maintained by its BRCs and collections and to facilitate their use by a large research community, from agriculture research to life sciences and environmental sciences. Its added value relies on sharing skills, harmonizing practices, triggering projects in comparative biology, and ultimately proposing a single-entry portal to facilitate access to documented samples, taking into account the partnership policies of research institutions as well as the legal frame which varies with the biological nature of resources. BRC4Env currently includes three BRCs: the Centre for Soil Genetic Resources of the platform GenoSol, in partnership with the European Conservatory of Soil Samples; the Egg Parasitoids Collection (EP-Coll); and the collection of ichthyological samples, Colisa. BRC4Env is also associated to several biological collections: microbial consortia (entomopathogenic bacteria, freshwater microalgae…), terrestrial arthropods, nematodes (plant parasitic, entomopathogenic, animal parasitic...), and small mammals. The BRCs and collections of BRC4Env are involved in partnership with academic scientists, as well as private companies, in the fields of medicinal mining, biocontrol, sustainable agriculture, and additional sectors. Moreover, the staff of the BRCs is involved in many training courses for students from French licence degree to Ph.D, engineers, as well as ongoing training.  相似文献   
650.
探究复垦土壤微生物量碳与基础呼吸的特征及其演变归因,有助于监测复垦土壤质量演变,并为提高复垦土壤质量提供科学依据。利用“空间代替时间”的方法研究了邹城东滩矿区复垦土壤微生物量碳(MBC)与基础呼吸(SBR)随复垦年垦的变化及其与土壤环境因子的关系。结果表明:复垦土壤MBC和微生物熵(qSMBC)随复垦年限呈增加趋势;复垦土壤SBR均显著高于对照,土壤代谢熵(qCO2)随复垦年限趋于降低,复垦后土壤微生物量逐渐恢复,同时土壤微生物对碳源利用效率逐渐提高,说明土壤环境逐渐有利于土壤微生物的生长。土壤MBC与碱解氮、总氮和有机碳呈极显著正相关(p<0.01),反映土壤养分缺乏是复垦后土壤微生物生长的主要限制因素。土壤代谢熵(qCO2)与土壤碱解氮、速效磷和MBC均呈极显著负相关(p<0.01)与pH呈显著正相关(p<0.05),说明氮磷等元素的缺乏以及较高的土壤pH环境是限制微生物生长的重要因素。这些对全面监测复垦后土壤质量的演变,并指导今后的复垦工作具有重要理论与实践意义。 关键词: 采煤塌陷区;土壤微生物量碳;土壤微生物熵;基础呼吸  相似文献   
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