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A review of studies addressing anorexia nervosa and bulimia nervosa among Native Americans, African-Americans, Hispanics, Asians, Africans, and Middle Easterners yielded only 35 studies, of which 22 were qualitative case reports, three were clinical quantitative studies, and ten were non-clinical quantitative studies. The case studies reported symptoms similar to those of Caucasian patients, and eating disorders were reported in all SES classes. The clinical studies, all reported from Asian countries, described a number of cases for eating disorders quite different from one another. The non-clinical quantitative studies reported a number of cases consistent with the ranges previously reported for controlled samples of non-clinical Caucasian populations. We found few or no quantitative studies on eating disorders from Hispanic, Middle Eastern, African, or Asian countries other than Japan.  相似文献   

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This review on hygienic, toxicologic and ecologic aspects of environmental burden of lead deals with the following topics: occurrence, production and use of lead; metabolism of lead and experimental toxicology of lead; toxicity of lead to man; hygienic and ecologic aspects of lead pollution. Lead ore mining and processing, production of lead-acid batteries and combustion of gasoline containing tetraethyl-lead as an anti-knock ingredient constitute at present the most important sources of lead pollution. The last named source of lead pollution in urban atmosphere is most hazardous to human health. Attempts to reduce this health hazard include use of additive-free gasoline, or replacement of tetraethyl lead by other anti-knock agents, e. g. by tetraethylcopper. The experiments with the use of organic compounds of manganese have failed to succeed. The possibility of biological monitoring of occupational and nonoccupational exposures to lead is discussed in detail in this review.  相似文献   

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Protein function annotation and rational drug discovery rely on the knowledge of binding sites for small organic compounds, and yet the quality of existing binding site predictors was never systematically evaluated. We assess predictions of ten representative geometry-, energy-, threading-, and consensus-based methods on a new benchmark data set that considers apo and holo protein structures with multiple binding sites for biologically relevant ligands. Statistical tests show that threading-based Findsite outperforms other predictors when its templates have high similarity with the input protein. However, Findsite is equivalent or inferior to some geometry-, energy-, and consensus-based methods when the similarity is lower. We demonstrate that geometry-, energy-, and consensus-based predictors benefit from the usage of holo structures and that the top four methods, Findsite, Q-SiteFinder, ConCavity, and MetaPocket, perform better for larger binding sites. Predictions from these four methods are complementary, and our simple meta-predictor improves over the best single predictor.  相似文献   

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A review of proposed sites of the dipsogenic action of angiotensin II is presented. Techniques used for such localization are critically discussed, and it is suggested that convergence of evidence from several different experimental techniques is required for localization of dipsogenic receptors. Loci suggested as such sites of action include the preoptic regions, the subfornical organ, and the tissue proximal to the optic recess of the third ventricle, including the organum vasculosum laminae terminalis. Current evidence suggests that there are at least two loci within the forebrain that possess dipsogenic receptors for angiotensin II.  相似文献   

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白车轴草(Trifolium repens)植株抗病性和生长与植物病史的关系   总被引:36,自引:4,他引:36  
从白车轴草(Trifolium repens)自然种群中采集无白车轴草单孢锈菌病史的无性系(clones)17个,有白车轴草单孢锈菌病史的无性系14个,分别作为抗病型和感受型植物实验材料;采集白车轴草单孢锈菌(Uromyces trifolii-repentis)菌系(strains)10个,作为病菌实验材料.分别设置并进行了两个温室实验、一个田间盆栽实验和一个原生长地移栽实验,实验处理上分对照、单菌系接种和10个菌系接种等3种.实验结果表明,无论是用单菌系接种还是10个菌系接种,植株发病的概率和程度均与其抗病性有关,抗病型植株(无病史)发病的概率和程度显著低于感受型(有病史)植株.在相同处理的实验中(无论是田间实验还是温室实验),无病史植株和有病史植株的生长无显著差异;不同处理田间实验植株的生长有显著差异,病情愈重,生长愈差.无病史植株的抗病性明显强于有病史植株.但是,原生长地的移栽实验结果表明,在无病原菌存在的情况下,有病史植株的(叶)生长显著好于无病史植株.可以认为,研究生物个体对环境因子反应性差异的实验应当在自然条件下和自然梯度范围内进行.  相似文献   

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Anaerobic digestion is one way of handling biowaste and generating energy in the form of methane (biogas). The digested residue may be used as fertiliser on agricultural land. Biowaste is known to contain pathogenic bacteria such as Salmonella and other microorganisms that may be a health risk for both people and animals. The biosecurity risk associated with using digested residue as fertiliser is hard to assess, but this risk cannot be neglected. It is of greatest importance that the treatment in the biogas plants (BGPs) minimise the survival of pathogens. Temperature is the most important factor when considering the reduction of pathogens in BGP, but there are also other factors involved. Different indicator bacteria are used to evaluate the hygienic treatment, but an indicator that is good enough to give an overall picture has not yet been found.  相似文献   

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Olive mill wastes exacerbate environmental problems in Mediterranean countries. These wastes are highly phytotoxic and contain phenolic compounds, lipids and organic acids. They also contain high percentages of organic matter and a vast range of plant nutrients that could be reused as fertilizers for sustainable agricultural practices. In this paper, recent research on composting wastes of 2-phase and 3-phase olive mills is reviewed, concentrating on factors affecting composting such as bulking agents, aeration strategy, physicochemical characteristics (duration of the thermophilic phase, moisture content, organic matter, volatile solids, total organic carbon, water soluble carbon, total nitrogen, total phosphorus, potassium, C/N ratio, phenols and the humification process), and phytotoxicity. The review highlights the effects of composting operational factors (bulking agent, additives, and aeration strategy) on the physicochemical characteristics of the final compost, and the production of a good quality soil amender or fertilizer.  相似文献   

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In this opinion paper, we offer our perspective on our bioremediation research along with the methods to assess its effectiveness as a safe and beneficial technology to remediate selected soil sites. The isolation and characterization of bacterial isolates from chemically contaminated soils, their survival and catabolic activity in contaminated soil, toxicity testing in chemically contaminated soils, molecular‐based methods of detection such as the polymerase chain reaction (PCR) and DNA probing are discussed. By using numerous conventional microbiological, chemical techniques, and molecular based methods, bioremediation can be studied in a comprehensive manner and the technology transferred to the commercial sector.  相似文献   

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Synergy was found between sulphonamide and trimethoprim in ratios 1:1 and 20:1 against both trimethoprim-sensitive enterococci (17 strains) and trimethoprim-resistant enterococci (23 strains). Many of these strains were resistant to kanamycin, tetracycline, streptomycin and/or erythromycin. Resistance to kanamycin, but not to trimethoprim, was clearly associated with the presence of a plasmid of molecular weight 35-45 Md. Elimination of this plasmid in three out of four highly trimethoprim resistant strains brought about loss of resistance to both kanamycin and trimethoprim. Furthermore, it was possible to transfer trimethoprim resistance from three of five highly resistant strains, but not from three strains with low-grade resistance. It is concluded that resistance to trimethoprim in enterococci can be encoded on a plasmid, and that the gene responsible may be on a transposon. No significant differences were found between the specific activities of dihydrofolate reductase from trimethoprim-sensitive and -resistant strains. The enzyme from resistant strains was several orders of magnitude less susceptible to inhibition by trimethoprim than was the enzyme from sensitive strains.  相似文献   

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资源化利用是应对餐厨垃圾(Kitchen waste,KW)和剩余污泥(Excess sludge,ES)快速增加的有效方法,而厌氧发酵获得挥发性脂肪酸(Volatile fatty acids,VFAs)是其中的重要方式之一,但单一底物限制了VFAs的高效生产.近年来,不同底物厌氧共发酵产生VFAs被广泛研究与应用,...  相似文献   

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Given the scale of the contamination associated with 60 years of global nuclear activity, and the inherent high financial and environmental costs associated with invasive physical and chemical clean-up strategies, there is an unparalleled interest in new passive in situ bioremediation processes for sites contaminated with nuclear waste. Many of these processes rely on successfully harnessing newly discovered natural biogeochemical cycles for key radionuclides and fission products. Recent advances have been made in understanding the microbial colonization of radioactive environments and the biological basis of microbial transformations of radioactive waste in these settings.  相似文献   

14.
Quantitative aspects of reactive gliosis: A review   总被引:27,自引:0,他引:27  
Recent studies of gliosis in a variety of animal models are reviewed. The models include brain injury, neurotoxic damage, genetic diseases and inflammatory demyelination. These studies show that reactive gliosis is not a stereotypic response, but varies widely in duration, degree of hyperplasia, and time course of expression of GFAP immunostaining, content and mRNA. We conclude that there are different biological mechanisms for induction and maintenance of reactive gliosis, which, depending on the kind of tissue damage, result in different expressions of the gliotic response.Special issue dedicated to Dr. Alan N. Davison.  相似文献   

15.
The epsilon wave of the electrocardiogram (ECG) together with fragmented QRS (fQRS), the terminal conduction delay, incomplete right bundle branch block (IRBBB) and complete/advanced RBBB (CRBBB) of peripheral origin are part of a spectrum of ventricular depolarization abnormalities of arrhythmogenic cardiomyopathy (AC). Although the epsilon wave is considered a major diagnostic criterion for AC since 2010 (AC Task Force Criteria), its diagnostic value is limited because it is a sign of the later stage of the disease. It would be more appropriate to say that the epsilon wave is a “hallmark” of AC, but is of low diagnostic sensitivity. Although the epsilon wave has high specificity for AC, it can be present in other pathological conditions. In this update we will cover the nomenclature, association with disease states and electrocardiographic aspects of the epsilon wave.  相似文献   

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Summary The microbiological aspects of a novel process of grape marc composting have been investigated. It has been possible to determine the succession of populations during the process which are required to obtain the required final product. The initial population comprises exclusively yeasts which, by autolysis and subsequent binding of the residual alcohol by esterifying reactions, enable rapid appearance of a mixed population of bacteria. The temperature increase continued by this bacterial flora favours growth of a thermophilic fungal flora, which is mainly responsible for the microbial decomposition process. The most important organism is Thermomyces lanuginosus Tsiklinski. Final humification is effected by a mixed population of Streptomycetes.It was possible to optimize the process by installing heat exchangers, thereby creating optimum conditions for the most important organism, T. lanuginosus.  相似文献   

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With more and more plastics being employed in human lives and increasing pressure being placed on capacities available for plastic waste disposal, the need for biodegradable plastics and biodegradation of plastic wastes has assumed increasing importance in the last few years. This review looks at the technological advancement made in the development of more easily biodegradable plastics and the biodegradation of conventional plastics by microorganisms. Additives, such as pro-oxidants and starch, are applied in synthetic materials to modify and make plastics biodegradable. Recent research has shown that thermoplastics derived from polyolefins, traditionally considered resistant to biodegradation in ambient environment, are biodegraded following photo-degradation and chemical degradation. Thermoset plastics, such as aliphatic polyester and polyester polyurethane, are easily attacked by microorganisms directly because of the potential hydrolytic cleavage of ester or urethane bonds in their structures. Some microorganisms have been isolated to utilize polyurethane as a sole source of carbon and nitrogen source. Aliphatic-aromatic copolyesters have active commercial applications because of their good mechanical properties and biodegradability. Reviewing published and ongoing studies on plastic biodegradation, this paper attempts to make conclusions on potentially viable methods to reduce impacts of plastic waste on the environment.  相似文献   

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大气有机氮沉降研究进展   总被引:8,自引:5,他引:8  
郑利霞  刘学军  张福锁 《生态学报》2007,27(9):3828-3834
大气氮素沉降是全球氮素生物地球化学循环的一个重要部分,包括干?湿沉降两种,以无机态和有机态形式发生沉降。长期以来由于受研究方法的限制,国际上对大气氮素沉降的研究多集中在无机态氮的沉降上,忽视了对有机态氮形式发生的沉降,因而造成了人们对大气氮素沉降总量的低估。在全面总结国内外文献的基础上,综述了大气有机态氮沉降的研究进展,具体包括大气有机氮的来源、种类?雨水有机氮的测定方法?有机氮沉降对大气氮沉降总量(氮沉降总量=无机氮沉降 有机氮沉降)的贡献,以及有机氮沉降可能的生态效应等。最后,指出了今后我国大气有机氮沉降研究需要加强的主要方面。  相似文献   

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Many proposed examples of reciprocal altruism are either misidentified or involve questionable assumptions concerning the costs and benefits accruing to the interactors. Waltz's (Am. Nat. 118: 588–592, 1981) definition of reciprocal altruism as an interaction in which “one individual aids another in anticipation that the recipient will return the favor benefiting the actor in the future” is not sufficiently restrictive: there must also be a direct fitness cost to the individual performing the original beneficent act that is less than the fitness benefit received when the act is reciprocated (again at a cost) by the second individual.Several recurring problems in identifying potential examples of reciprocal altruism are discussed, including the assumption that restraint is an act of altruism and the misclassification of “generational mutualisms,” in which individuals helping to raise young are “repaid” one generation later by the offspring they assisted in raising. No definite case of reciprocal altruism is currently known in birds, but examples in which this phenomenon may be involved include helping behavior in a few cooperative breeders and communal feeding in several taxa including gulls, jays, and juncos.  相似文献   

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