PCB118对GT1-7细胞GnRH分泌及Kisspeptin/GPR54信号通路蛋白表达的影响

为研究多氯联苯118(polychlorinated biphenyl 118,PCB118)对GT1-7细胞的毒性作用,探讨其对促性腺激素释放激素(gonadotropin-releasing hormone,GnRH)分泌的影响及相关机制,在PCB118作用GT1-7细胞后,分析了细胞存活率、GnRH分泌水平以及Kisspeptin/GPR54信号通路中关键蛋白的表达水平。结果表明,PCB118(0.05～50 000 nmol·L-1)分别作用GT1-7细胞6、12、24和48 h后,细胞存活率随PCB118浓度的增加和作用时间的延长而显著降低。但只有在高浓度(50 000nmol·L-1)条件下,PCB118才能显著促进GT1-7细胞释放乳酸脱氢酶(lactate dehydrogenase,LDH)。PCB118作用GT1-7细胞6 h后,5、500和50 000 nmol·L-1组能显著抑制GnRH的分泌,并降低Kisspeptin/GPR54信号通路中GnRH、G蛋白偶联受体54(G-protein-coupled receptor 54,GPR54)、磷脂酶C(phospholipase C,PLC)和蛋白激酶C(protein kinase C,PKC)等关键蛋白的表达水平;作用24 h,500和50 000 nmol·L-1PCB118能显著抑制GnRH的分泌,并降低GnRH、GPR54、PLC和PKC等关键蛋白的表达水平。研究表明:PCB118对GT1-7细胞具有细胞增殖毒性作用,呈现一定的剂量和时间效应; PCB118能在一定程度上抑制GT1-7细胞GnRH的合成与分泌,并下调Kisspeptin/GPR54信号通路中GnRH、GPR54、PLC和PKC等关键蛋白的表达水平,推测Kisspeptin/GPR54信号通路可能参与介导了PCB118对GT1-7细胞GnRH分泌的抑制作用。     

So animal a human ..., or the moral relevance of being an omnivore

It is argued that the question of whether or not one is required to be or become a strict vegetarian depends, not upon a rule or ideal that endorses vegetarianism on moral grounds, but rather upon whether one's own physical, biological nature is adapted to maintaining health and well-being on a vegetarian diet. Even if we accept the view that animals have rights, we still have no duty to make ourselves substantially worse off for the sake of other rights-holders. Moreover, duties to others, such as fetuses and infants, may require one to consume meat or animal products. Seven classes of individuals who are not required to be or become vegetarians are identified and their examption is related to nutritional facts; these classes comprise most of the earth's population. The rule of vegetarianism defines a special or provisional duty rather than any general or universal rule, since its observance it based upon the biological capacities of individual humans whose genetic constitution and environment makes them suitably herbivorous. It is also argued that generalizing the vegetarian ideal as a social goal for all would be wrongful because it fails to consider the individual nutritional needs of humans at various stages of life, according to biological differences between the sexes, and because it would have the eugenic effect of limiting the adaptability of the human species. The appeal to the natural interests of omnivores will not justify any claim that humans may eat amounts of meat or animal products in excess of a reasonable safety margin since animals have rights-claims against us.     

Amniotic fluid macrophages from normal and malformed fetuses

Amniotic fluid cells from normal and abnormal fetuses (neural tube defects and abdominal wall lesions) were examined uncultured and after short-term culture for macrophages. Morphology, adherence, phagocytosis, presence of Fc receptors and non-specific esterase were studied. The existence of macrophages in normal and abnormal fluids was confirmed, although the percentage and the absolute numbers varied greatly from specimen to specimen. The most marked increases in total macrophages were in cases of anencephaly. The significance of these macrophages and their value in prenatal diagnosis are discussed.     

论"风水"精华与生态环境保护

风水是人们追求理想生存环境的一门学科,它在中国传统文化中影响极大,其理论中体现了许多现代环境学的先进思想。通过对风水学的再研究,发现在很早以前的风水学中就有可持续发展的思想,本文从科学的角度对风水学中的“气”,“脉”,“形”进行重新诠释,并叙述了风水与生态环境保护密不可分的关系。     

北环铁路地质安全性研究

影响铁路工程安全的因素有很多,最基础的因素应是工程的地质安全性。针对北环铁路所处的特殊工程地质环境,分别从黄土特性、人类活动、地震液化和土动力学性质等几个方面,论述铁路的地质安全性,分析铁路工程与地质环境的相互作用,研究人类活动对工程地质环境的改变及其影响程度,可以认为:黄土对工程安全的影响不仅仅在于其湿陷性,更在于对其的认知和软化、触变特性;人类活动的负面作用也同样影响着地质的安全作用,不仅改变其原来地貌,也改良了土的安全性质,铁路附近的饱和软黄土就是人类活动改造地质环境的结果;土的动力学特性对工程安全起着潜移默化的作用;最后指出铁路工程的安全性是建立在地质安全性的基础上。     

试论公民环境权的性质

公民环境权是在环境危机产生后才愈加受人关注.本文通过对公民环境权的定义的探讨,对公民环境权的性质进行剖析,并且认为公民环境权是一项法定权利,它是由生存权发展而来的一项基本人权.但期待高位阶的法律做出更为明确的规定.     

对人的认识和假设是人机工程学的基石

人机系统是以人为中心的系统，对人的认识和假设是人机工程学的基石。本文提出了人是生物人、经济人、社会人的复合体的新观点。由于对人的特质的认识还存在着许多“盲区”和“误区”，这就给人机工程学的完善和发展带来了许多不定因素和困难     

Exposing violences: Using women's human rights theory to reconceptualize food rights

Exposing food violences – hunger,malnutrition, and poisoning from environmentalmismanagement – requires policy action thatconfronts the structured invisibility of theseviolences. Along with the hidden deprivation offood is the physical and political isolation ofcritical knowledge on food violences and needs,and for policy strategies to address them. Iargue that efforts dedicated on behalf of ahuman right to food can benefit from thetheoretical analysis and activist work of theinternational Women's Rights are Human Rights(WRHR) movement. WRHR focuses on women andgirls; the food rights movement operates onbehalf of all people, with an emphasis on thepoor. Both attend to the protection of bodilyintegrity against physical and psychicviolences. Both cope with bodily violences thatare socially privatized and spatiallysegregated from public institutions of relief,that is, they are tacitly omitted from publicdiscourse and purview. Most typically, but notexclusively, these violences unfold in privatehousehold space. Both rights movements mustmobilize political rights to demand economicand social rights and security. I introduce theUnited Nations' early Declaration (1948) andCovenant (1966) language on the human right tofood and review problems of household accessand grassroots engagement that are ``writteninto' this early documentation. An abbreviatedoverview of the WRHR movement describes how thepublic/private and economic/political rightsdichotomies have been critiqued andre-formulated. A case study set in Polandacross the transition from (more) communist to(more) capitalist political economies attemptsto illuminate the discussion through agrounded example.     

HYDROLOGIC STAGE PERIODICITY OF THE MISSISSIPPI RIVER BEFORE AND AFTER SYSTEMATIC CHANNEL MODIFICATIONS1

ABSTRACT: Periodic flood disturbance is a well known controlling factor of in channel and floodplain ecosystem function. However, channel manipulations during the last century have potentially altered hydrologic fluctuations, and thus ecosystem function. We examined temporal river stage hydrology, through autocorrelation analysis, at seven gauges along the Mississippi River to quantify flow periodicity and effects of systematic channel modifications on flow periodicity. Intraannual variation follows a strong one‐year cycle of six months higher flow and six months lower flow for the entire Mississippi River drainage, with precipitation as a driving force. Interannual hydrologic variation differs between the upper and lower river segments. A clear quasi‐biennial oscillation pattern was evident throughout the lower river section. The effect of channel alterations was a decreased magnitude of differences between lower and higher flows. The upper section, however, suggests a 12‐to 14‐year periodicity prior to alterations and a decreased duration of lower flow years following systematic modifications. Interannual variograms clearly depict very different temporal hydrology between the upper Mississippi River and the lower Mississippi River, suggesting the simple transfer of knowledge from one segment to the other oversimplifies the complexity of a large river system.     

一种人因可靠性分析(HRA)方法

从控制论角度说明人因可靠性分析方法，在分析现有两代人因可靠性分析方法不足的基础上，结合控制论，提出了一种新的人因可靠性分析方法的构想。