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Neuronal oscillations in the human brain   总被引:1,自引:0,他引:1  
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In this investigation the original observation of a correlation between the concentration of amniotic fluid albumin and maternal serum alpha fetoprotein (AFP), as a proof for amniotic fluid-derived AFP in the maternal compartment is confirmed at 15 and 16 weeks of gestation. In contrast to the earlier reported highly significant relation in this study the correlation is only weak, especially at 15 weeks. This might be in agreement with a more frequent absence of raised maternal serum AFP levels in cases of raised amniotic fluid AFP levels prior to 16 weeks of gestation. Transamniotic AFP transport contributes a minor part of the AFP present in the maternal compartment, as also indicated by the lack of correlation between AFP concentrations in amniotic fluid and maternal serum.  相似文献   

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 The heritability and evolvability of lifespan in two socioeconomically different groups of humans, including birth cohorts for 1600–1800s, were investigated. Among the aristocratic Europeans, the heritability estimates based on offspring–mother regressions ranged from 0.46 to 0.89, while the estimates based on offspring–father regressions varied from 0.23 to 0.59. However, the rural Finns possessed either no inheritable component or a clearly lower level of heritability than did the aristocrats, the estimates ranging from 0 to 0.40, depending on the method used. The additive genetic coefficients of variation and standardized evolvabilities were high in the aristocrats, especially in the data set including all data instead of limiting the data to the older age group. Among rural Finns, the values were considerably lower. Received: 1 September 2000 / Accepted in revised form: 6 November 2000  相似文献   

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A debate of the merits of human space travel as opposed to robots is presented. While robotic space travel would be considerably less expensive, the author takes the position that there are certain skills and research abilities that only humans possess. Human contributions to past lunar exploration are considered, along with a discussion of the interaction of humans with robotics or other artificial intelligence or computer driven technologies. The author concludes that while robots and machines are tools which should be incorporated into space travel, they are not adequate substitutes for people.  相似文献   

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The great majority of genetic defects underlying steroid 21-hydroxylase deficiency appear to result from intergenic recombinations between the homologous CYP21 and CYP21P genes. For a minority, novel sporadic point mutations have been detected. De novo mutations in CYP21 have also been reported, but only a few studies have systematically screened their occurrence. We here describe a population-based patient sample in order to estimate the rate of single-family (i.e. sporadic) and de novo germline mutations in the human CYP21 locus. Among 76 Finnish families were observed three single-family mutations and two de novo mutations in CYP21. The rates obtained, ∼5% and ∼2% for novel and de novo mutations, respectively, indicate that they are not rare and that their occurrence should not be ignored in genetic diagnostics of this disorder. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   

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We thank H. Thiel for technical help and Nicolet Instruments Company, especially M. Mosimann, Zürich, for the loan of a Nicolet Compact Four.  相似文献   

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取代苯对人体细胞的定量结构—遗传毒性研究   总被引:1,自引:1,他引:0       下载免费PDF全文
通过微核实验,测定了 36 种取代苯类化合物对人体外周血淋巴细胞的遗传毒性;并构建了遗传毒性与分子结构参数之间的 QSAR 模型.结果表明,有 34 种化合物显著地导致了微核的产生,具有明显的遗传毒性;遗传毒性的大小与分子结构描述符辛醇-水分配系数(MlogP)、x 轴主惯性矩(Principalx)、γ 极化率[Polar(γ)]等存在良好的结构-活性相关关系,所建模型的相关系数 R2 =0.718,具有较高的预测能力,可用来预测取代苯类化合物的遗传毒性.  相似文献   

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Six biochemical parameters and four enzyme activities were determined from the serum of 76 healthy and 56 pathological human fetuses between the 20th and 38th week of pregnancy. In the normal fetuses studied within that period, creatinine, immunoglobulin M, lactate dehydrogenase, and gamma-glutamyltransferase increased; haemoglobin F and glucose progressively decreased; and alkaline phosphatase was at a peak around the 26th week; cholesterol and triglycerides were always low. The same parameters were also measured in some of the pathological fetuses and compared with their normal counterparts.  相似文献   

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本文确认了全球社会-生态问题(过度消费,道德危机)的主要根源并提出了新的可持续发展的愿景,重点要关注精神、道德、心理、生理和人的智力开发(而代替以消费为导主的理念)。讨论了人类发展指标不足所涉及到的因素(寿命预期、人均国内生产总值),提出了测量人类可持续发展的替代指标,即:健康人口的比例。生态效率也被建议作为转化可持续发展的必要条件,人的精神,根据生态中心立场(社会-生态幸福)。通过适当的教育和体制政策而实现环境和人类健康、公平和整个人类的发展。  相似文献   

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<正>Introduction Cadmium is considered a human carcinogen by the International Agency for Research on Cancer(IARC,1993)and the US National Toxicology Program(NTP,1997).Cadmium contamination of food crops is a persistent issue for both the agricultural industry as well as consumers.This is an issue for agriculture because cadmium can be present in soils naturally or as a result of industrial processes and can contaminate foods that are consumed by humans.Industrial  相似文献   

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人类活动在武汉东湖沉积物中的记录   总被引:9,自引:0,他引:9       下载免费PDF全文
研究了武汉东湖Ⅰ站90cm和Ⅱ站150cm沉积物柱芯TOC、TN、TP和硅藻的垂向分布,探讨了在东湖的发展演化中尤其是富营养化的过程中人类活动的影响.在350aBP(清朝康熙雍正年间)和20世纪60年代,由于人口增长、农业耕作发展和湖泊富营养化使区域内TOC、TN等营养物质向湖内大量输入.东湖I站沉积物中TP在0~5cm的高值区主要与建国以来东湖周围的人类活动作用加强有关,是湖泊营养程度逐步提高的结果.随着湖泊富营养化的加剧,湖泊藻类大量繁衍,沉积物中保存的硅藻也相应大量增加.  相似文献   

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