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研究表明,微量元素对人体健康有重要的作用。硒是人体中必需的微量元素。由于地壳表面含硒量不同,人类在不同地区生活,血液内硒值不一致。血硒水平低易发生缺硒引起的疾病,过量则发生中毒症状。因此,有必要了解各地正常人群血硒的水平。我们于1986年9月对杭州市224例健康成年人进行了血硒水平的调查。 相似文献
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贵港市富硒农产品发展现状及开发策略研究 总被引：1，自引：0，他引：1
目的:提出有利于贵港富硒农产品开发的规划建议。方法:研究贵港市耕地土壤硒资源的分布规律,实验测定了贵港市耕地土壤的含硒量,得出贵港市耕地土壤的硒含量、分布情况。实验还测定了贵港市主要农作物的含硒量。结果:富硒土壤资源是贵港农业待开发的天然"金矿",开发优质天然富硒农产品是贵港农业转型升级的最佳选项,加快挖掘利用开发富硒农业产业资源,更是促进贵港农业提质增效,促进农民增收的最佳途径。存在问题:认知度不够、投入财力缺乏、品牌标准意识不强、监督机制未形成、产业规划未形成。建议:形成共识、制定规划、打造品牌、宣传推介、加大投入、强化认证与监管。 相似文献
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农作物“增硒增产”技术是一项集增硒与增产为一体的适用新技术，它是发展“两高一代”农业，开发绿色食品的有力措施。在农作物上大面积应用开发研究增硒增产技术，对于增加粮食产量、提高其品质，开发绿色食品形成国内外市场上具有竞争力的名牌产品，发展优质家禽畜牧业，防治缺硒而引起的多种疾病，增强免疫力，防癌、抗癌，提高中华民族健康水平，有着十分重要的意义。 相似文献
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为探讨富硒带蔬菜对硒的富集效果,在青海省乐都县富硒带进行了试验。结果表明：试验区土壤含硒量处于富硒水平,试验作物硒积累结果都是富硒产品。 相似文献
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选取迄今世界上唯一发生过人群硒中毒爆发性流行的地区———湖北恩施渔塘坝为研究区.研究结果表明,在渔塘坝废弃的 石煤堆"和富硒岩段,首次发现了多形态、多成因的自然硒和硒铜蓝、水硒铁石等硒的独立矿物,证实了富硒岩石中自然硒的存在.富硒岩石中硒主要以有机结合态和残渣态硒为主.元素硒的形成过程是影响风化岩石硒释放、转化和迁移的重要因素.富硒岩石是渔塘坝高硒区形成的直接因素.硒中毒的高风险主要受玉米硒(主食)的控制,渔塘坝目前依然是硒中毒可能发生的高风险区. 相似文献
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渔塘坝黑色富硒岩石中硒的赋存状态及其对局域环境的效应研究 总被引：1，自引：0，他引：1
选取迄今世界上唯一发生过人群硒中毒爆发性流行的地区--湖北恩施渔塘坝为研究区.研究结果表明,在渔塘坝废弃的"石煤堆"和富硒岩段,首次发现了多形态、多成因的自然硒和硒铜蓝、水硒铁石等硒的独立矿物,证实了富硒岩石中自然硒的存在.富硒岩石中硒主要以有机结合态和残渣态硒为主.元素硒的形成过程是影响风化岩石硒释放、转化和迁移的重要因素.富硒岩石是渔塘坝高硒区形成的直接因素.硒中毒的高风险主要受玉米硒(主食)的控制,渔塘坝目前依然是硒中毒可能发生的高风险区. 相似文献
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荞麦富硒试验研究及其开发前景 总被引：7，自引：0，他引：7
刘湘元张宏志王建立管正学 《资源科学》1998,20(6):61-66
微量元素硒是人体必需的生命元素。我国72%的地区处于缺硒、低硒带,约有3×108人口受到缺硒威胁。因此,开发富硒食品是关系到我国人民健康的重要课题。本文详细报道了荞麦作物富硒试验研究的方法和结果。研究结果表明,通过拌种和花期叶面喷施亚硒酸钠,荞麦富硒效果十分明显荞麦、富硒试验、开发利用 相似文献
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本文综述了微量元素硒在人体的存在形式及分布情况,探讨了硒对人体的生理保健功能,分析了人体硒的需求量以及缺乏、过量对人体的影响,并对亚硒酸钠、富硒酵母、硒蛋白及硒化卡拉胶四种硒营养强化剂的特征及其在食品生产中的应用进行了介绍。 相似文献
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阐明了分级萃取过程中存在萃取剂的非选择性及痕量金属元素在萃取过程中的再吸附与再分配问题。实验证明了不同土壤类型与不同元素形态决定不同的生物可给性。采用植物根际分泌的低分子量有机酸作萃取剂 ,可较好地预测金属形态与生物可给性的关系。基于腐殖酸的结构柔性、多官能团性与聚电解质性 ,发展了多配位体表面络合模型 ,并用于研究界面反应。建立了新的青海湖菌Q6 7生物毒性测试方法 ,可应用于淡水体系。根据硒在环境 (水、土壤、植物、动物 )中的不同形态 ,较好地解释了中国低硒带大骨节病人缺硒的原因 相似文献
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采用廉价的催化剂代替昂贵的金属,低成本的一氧化碳代替氢气乃至光气,一直是人们追求的目标.综述了非金属硒在含碳、氮、氧、硫类有机化合物中的催化羰基化反应,以及在Se/CO/H2 O体系中一些有机化合物的高选择性还原反应,介绍了近期的一些新进展.催化剂量的硒在温和条件下,即可活化一氧化碳而直接进行羰基化和还原反应,特别是发展了将硝基化合物的还原羰基化与胺的氧化羰基化相结合,合成一系列精细化学品和生物化学品.催化剂硒在催化反应中表现出反应过程相转移的特性,兼具了多相催化与均相催化的优点,是反应过程相转移概念中的典型实例.硒催化反应的特点是反应物转化率高,反应选择性专一,原子经济性高,对环境友好,且可部分替代光气合成法 相似文献
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Milne R 《Social studies of science》2012,42(2):290-306
The paper explores the role of imagined geographies in the shaping of new technologies. I argue that the role of place in future-oriented visions of technoscience is a neglected topic in studies of the social shaping of technology. The paper proposes an approach that combines the sociology of expectations with the geography of science. It focuses on the interplay between envisaged and current geographies to highlight the recursive dynamics of place and imagination. To illustrate this approach, the paper discusses the example of biopharming, the production of biopharmaceuticals using genetically modified crops. I argue that expectations for biopharming bear the imprint of place, or rather of the places in which they are imagined, as well as those they imagine, and ultimately those they produce. I use this example to suggest how social studies of science and technology can usefully investigate the spaces, places and scales of technological development. 相似文献
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Jason W. Patton 《Ethics and Information Technology》2000,2(3):181-187
While maintaining the importance of privacy for critical evaluations of surveillance technologies, I suggest that privacy also constrains the debate by framing analyses in terms of the individual. Public space provides a site for considering what is at stake with surveillance technologies besides privacy. After describing two accounts of privacy and one of public space, I argue that surveillance technologies simultaneously add an ambiguityand a specificity to public places that are detrimental to the social, cultural, and civic importance of these places. By making public places accessible to other places and/or times, surveillance technologies make these social contexts ambiguous by blurring their spatial and temporal bounds. At the same time, surveillancetechnologies valence public places in functionally specificways that are detrimental to informal civic life. To complement defensive approaches to surveillance technologies based onindividual privacy, I conclude by suggesting how sociality as a relational value or an ethics of place as a contextual value could provide a proactive line of reasoning for affirming the value ofthat which is between people and places. 相似文献
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能源作物资源现状与发展前景 总被引：33，自引：0，他引：33
能源作物是生物质能源发展的基础环节,本文就国内外能源作物研究现状与前景进行综合述评。分析了能源作物的基本概念和分类,明确了适合中国国情的能源作物概念,归纳了当前淀粉与糖料作物、油脂作物和木质纤维素作物三类能源作物研究与应用现状。重点介绍了当前几种受国内外重视的新型能源作物甜高粱(Sorghum bicolor)、木薯(Manihot esculenta)、柳枝稷(Panicum virgatum)、芒属植物(Miscanthusspp.)和柳属植物(Salixspp.)的发展现状和前景。从土地的承载能力和对环境的影响方面分析了中国发展发展能源作物的存在的问题与前景,明确提出,中国要坚持利用边际性土地、与生态恢复相结合发展能源作物的原则。指出中国能源作物种类筛选及品种改良至关重要,选择目标上应重视高光效、多年生、以收获营养器官为收获对象和高度抗逆等特征,以期形成具有地区适应性且收获季节多样化的系列能源作物种类与品种。 相似文献
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Oudshoorn N 《Social studies of science》2012,42(1):121-142
Dominant discourses on telecare technologies often celebrate the erasure of distance and place. This paper provides a critical intervention into these discourses by investigating how spaces still matter, despite the move from physical to virtual encounters between healthcare professionals and patients. I argue that science and technology studies (STS) research on telecare, as well as other technologies, can be enriched by including a focus on place to understand the dynamic interactions between people and things. Adopting insights of human geographers, I show how places in which technologies are used affect how technologies enable or constrain human actions and identities. Whereas some spaces may facilitate the incorporation of technologies, others may resist technologies. A focus on how places matter is important for understanding how telecare technologies reorder and redefine healthcare. Although other healthcare technologies are also important actors in transforming healthcare, telecare technologies do this in a very specific way: they redefine the spatial dimensions of healthcare. To capture and further explore this changing spatial configuration of healthcare, I introduce the notion of technogeography of care. This concept provides a useful heuristic to study how places matter in healthcare. Although telecare technologies introduce virtual encounters between healthcare providers and patients, the use of telecare devices still largely depends on locally grounded, situated care acts. Based on interviews with users of several cardiac telecare applications, including healthcare professionals and patients in Germany and The Netherlands, the paper shows how patients' homes and public spaces are important for shaping the implementation and use of telecare technologies, and vice versa. Last, but not least, telecare devices are implicated as well. The paper emphasizes the place-dependency of the use and meaning of technical devices by showing how the same technological device can do and mean different things in different places. 相似文献
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Will synthetic biology elicit controversies similar to those of genetically modified crops before? Maybe, but where exactly are the analogies, and how can we gain substantial insights rather than mere guesses? We argue that as well as the intrinsic properties of the technologies at stake, the context of their implementation is decisive. To assess mechanisms of past and potential controversies, an investigative tool is presented. The Gate Resonance model, derived from older models of societal conflict, allows the identification of key elements of conflict generating processes. In monitoring the developing debate on synthetic biology using this model, analogies to the case of genetically modified crops appear less convincing. So far, there are only few indications that a controversy is imminent. 相似文献
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大城市郊区农户要素投入特征及差异分析——以北京市平谷区为例 总被引：3，自引：2，他引：3
农户生产要素投入的方向和强度不仅反映了农户的经济行为特征，也在一定程度上决定了区域农业的发展方向。本文以北京市平谷区2003年的116个农户调查问卷为基础，对大城市郊区农户生产要素投入特征及其差异进行了分析。结果表明，由于预期收益不同，农户在各产业的劳动力投入数量、质量、物质投入水平和组合结构具有很大差异。在劳动力质量和数量投入方面，根据建立的劳动力质量投入模型进行计算，平谷区农户劳动力质量投入水平非农产业要高于农业产业，经济作物要高于大田作物，具体从高到低的顺序依次是非农产业、其他经济作物、畜牧业、菜地、果园、大田作物，同时劳动力从农业向非农产业、在农业内部从大田作物向经济作物转移的趋势明显；在农户物质投入水平和组合结构方面，资本投入水平从高到低的顺序是：果园、菜地、大田，要素投入组合结构从好到差的顺序是：菜地、果园、大田，两个排序中经济作物都要高于或好于大田作物。分析认为稳定市场预期对于大城市郊区农业的健康发展具有十分重要的意义。 相似文献
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M. M. Goyal A. K. Kalwar R. K. Vyas A. Bhati 《Indian journal of clinical biochemistry : IJCB》2006,21(1):208-210
The association of serum trace elements like selenium, zinc and copper has been found in different types of cancer. This study
was conducted to see the serum level of these three trace elements in cancer esophagus patients. Biopsy confirmed cancer esophagus,
24 patients (12 males, 12 females, mean age 54.5±11.65 year with 23 healthy subjects (16 males, 7 females, mean age 44 ±13.82
years) were included in this study. Both control and study group patients were of same socio-economic status and dietary habits.
Serum zinc and copper level were estimated using standard absorption spectrometer technique and serum selenium by Hydride
generation method.
We observed significant low serum levels of zinc and selenium while high level of serum copper in carcinoma esophagus patients,
as compared with normal healthy controls. This shows an association of serum selenium zinc and copper with cancer esophagus. 相似文献