| 词条 | SDG |
| 释义 | 科学数据网格的简称，是在中国科学院科学数据库的基础上，利用数据网格技术连接分布在全国的四十多个研究所而建设的一个共享平台和应用环境。研制过程中，得到了中国科学院“十五”信息化建设专项、科技部863计划、科技部国家科技基础条件平台工作、自然科学基金重大研究计划等多项科研经费的支持。2003年12月发布了科学数据网格软件包的第一个版本（SDG1.0），2004年12月发布了第二个版本（SDG2.0），2005年8月发布了第三个版本，并已在科学数据库的建库单位进行了推广部署。截止目前，软件使用情况良好，得到用户的广泛好评。 科学依据科学数据网格软件的主要目标是建立科学数据库的统一安全体系，实现科学数据库分布式、异构资源的统一访问接口，由SDG中间件和SDG工具集构成。信息服务存储数据服务所需的核心目录信息，为数据访问服务提供目录服务；数据访问服务是SDG中间件的核心部分，它建立在由安全体系构建的安全环境下，对外提供统一的数据访问接口，屏蔽分布式环境中数据资源的多样性和异构性，消除数据孤岛和信息孤岛，实现科学数据库数据资源的集成与共享；存储服务为各建库单位提供数据存储、备份和网络服务；安全服务为SDG软件中其它模块提供认证和授权信息，确保数据访问的安全性。 核心服务SDG中间件的核心服务模块包括四个子系统。信息服务子系统是为网格中的数据资源提供统一的信息服务，包括数据资源的属性信息、状态信息和特有的元数据信息等，实现资源描述和资源发现等功能。数据访问服务子系统是为大规模、分布、自治、异构的数据资源提供统一的访问接口，以方便科学数据库数据资源的共享和集成。存储服务子系统提供具有数据传输、存储管理以及配额分配功能的存储服务，利用高速网络环境提供网络服务，从而更有效利用数据中心的海量存储资源，解决各建库单位数据存储、备份和开展网络服务的困难。安全体系子系统提供科学数据网格中的统一安全体系和相应服务，包括访问数据资源所需的单点登录、认证、访问控制和记账服务，实现对数据资源有控制、有保障、有效率的共享。 SDG中间件的应用服务模块是SDG中间件的基础上提供了一些管理和应用工具。包括数据量统计分析工具、通用元数据管理工具、科学数据库CA系统、网格门户、通用数据管理工具、数据目录管理工具、访问控制工具包和存储共享工具等 发展历史四百年前伽利略首次把望远镜指向天空，结束了人类一直用肉眼进行天文观测的历史。一百五十年前，照相技术和光谱技术开始在天文观测中应用，单纯以人眼作为天文探测器的时代结束，天体物理学诞生并发展成为现代天文学的主流。五十多年前，在第二次世界大战中得到蓬勃发展的无线电技术使得天文学家的视野超出了可见光，射电天文学诞生。此后不久宇航时代到来，空间天文学诞生，人类对宇宙的观测扩展到了伽马射线、X射线、紫外和红外波段。 从二十世纪九十年代开始，天文学正经历着革命性的变化。这一变化是由前所未有的技术进步推动的，即望远镜的设计和制造、大尺寸探测器阵列的开发、计算能力的指数增长以及互联网络的飞速发展。 望远镜技术的进步使得人类可以建造大型的空间天文台，为伽玛射线、X射线、光学和红外天文的发展开辟了新的前景，同时也推动了新一代的大口径地面光学望远镜和射电望远镜的建造。现在，天文学家们正在计划建造功能更好口径更大的空间和地面望远镜，并将配备尺寸更大象素更多的探测器。随着众多先进的地面与空间天文设备的投入使用，大规模的观测数据正在产生，例如目前哈勃空间望远镜每天大约产生50亿字节的数据，我国正在建造的LAMOST望远镜也将产生每天30亿字节的数据，美国计划建造的“大口径巡天望远镜”将会达到每天10万亿字节的量级！目前，世界天文学数据量增倍的周期已经缩短到一年以内。 使天文学研究发生重大变化的另一个技术进步是快速互联网技术，这使得异地天文数据的交换和处理成为可能，使得观测数据具有巨大的科学产出的潜在意义。 天文观测巡天，就是对整个天区进行观测、普查。如果利用伽马射线巡天、X射线巡天、紫外巡天、光学巡天、红外巡天和射电巡天所得到的观测数据，用适合的方法对数据进行统一规范的整理、归档，便可以构成一个全波段的数字虚拟天空；而根据用户要求获得某个天区的各类数据，就仿佛是在使用一架虚拟的天文望远镜；如果再根据科学研究的要求开发出功能强大的计算工具、统计分析工具和数据挖掘工具，这就相当于拥有了虚拟的各种研究设施。这样，由数字虚拟天空、虚拟天文望远镜和虚拟研究设施所组成的机构便是一个独一无二的虚拟天文台。 中医理论中医药虚拟研究院由全国20余家中医药大学、学院及研究院所的近300位中医药数据库建设工作者组成。包括：中国中医研究院中医药信息研究所、中国中医研究院医史文献研究所、上海中医药大学、成都中医药大学、广州中医药大学、北京中医药大学、黑龙江中医药大学、南京中医药大学、山东中医药大学、福建中医学院、湖北中医学院、辽宁中医学院、河南中医学院、山西中医学院、天津中医学院、陕西省中医药研究院、吉林省中医药研究院、江西省中医药研究院、河南省中医药研究院、浙江省中医药研究院、上海市中医药文献馆、重庆中药研究院、重庆中医研究院等单位。通过集成已开发的70多个中医药数据库，建立一个虚拟的支持中医药科学研究的应用网格环境，建设中医药虚拟研究院。 高能物理的研究与信息技术密切相关，无论是大规模实验数据的处理，还是科学计算，以及贵重设备的共享，都可以是网格技术的直接应用。事实上，网格的发展在很大程度上就是得益于高能物理研究的推动。目前，国际上有几个重要的网格项目都与高能物理有直接的关系，如EU DataGrid、GriPhyN、PPDG、GridPP、等等。因此，高能物理网格是一类最有代表性的网格应用。甚至可以说，网格计算将是近期解决高能物理实验这样的世界性合作的、数据量极大的科学工程计算问题的唯一途径。 2.亚麻木酚素 (SDG) 亚麻木酚素的英文名： Secoisolariciresinol Diglucoside；SDG; 2,3-Bis(3-methoxy-4-hydroxybenzyl)butane-1,4-diol 1,4-diglucoside 亚麻木酚素的分子式： C32H46O16亚麻木酚素的分子量： 686.71 亚麻木酚素的CAS No.： 148244-82-0 别名：亚麻木酯素，亚麻木脂素 纯度： 95%, 98%, 99% by HPLC 详细介绍物品介绍亚麻木酚素叫开环异落叶松酚二葡萄糖苷。这是与人体雌激素十分相似的植物雌激素。亚麻木酚素主要存在于亚麻籽中，其含量取决于亚麻品种、气候和生态条件，一般约占籽重量的0.9%～1.5%，比其它已知含木酚素的66种食品高100～800倍. 来源为亚麻科植物亚麻Linum usitatissimum L.的种子。 性状黄褐色粉末。 功能作用亚麻木酚素对雌激素依赖性疾病乳腺癌、前列腺癌、经期综合征、骨质疏松有预防作用。除此之外，临床研究显示亚麻木酚素对糖尿病、胃肠肿瘤、冠心病、肾脏病，抗氧化性都有有益的作用。 应用状况近年来，以加拿大、澳大利亚、英国和美国为主的西方发达国家，对亚麻籽作为功能食品的研究和开发作了大量的工作，以亚麻籽粉为代表的产品早已面市多年，成为中、老年人的常备保健品。最近，符合疗效性要求的高纯度、标准化木酚素提取物的产品也上市，可以广泛应用于胶囊、压片、谷物早餐和快餐食品的添加剂。还有含有ω-3脂肪酸、可溶性食物纤维和木酚素的营养功能性超浓乳状液和全乳饮料等多种产品不断出现在市场上。我国近几年一些工厂也开始研究亚麻木酚素的提取工作。 Lignans are naturally occurring chemicals widespread within the plant and animal kingdoms. Several lignans—with intimidating names such as secoisolariciresinol—are considered to be phytoestrogens, plant chemicals that mimic the hormone estrogen. These are especially abundant in flaxseeds and sesame seeds. Bacteria in our intestines convert the naturally occurring phytoestrogens from flaxseed into two other lignans, enterolactone and enterodiol, which also have estrogen-like effects. In this article, the term lignans refers to these two specific lignans as well as the phytoestrogen kind, but not to the wide variety of other lignans. Lignans are being studied for possible use in cancer prevention, particularly breast cancer. Like other phytoestrogens (such as soy isoflavones), they hook onto the same spots on cells where estrogen attaches. If there is little estrogen in the body (after menopause, for example), lignans may act like weak estrogen; but when natural estrogen is abundant in the body, lignans may instead reduce estrogen's effects by displacing it from cells. This displacement of the hormone may help prevent those cancers, such as breast cancer, that depend on estrogen to start and develop. In addition, at least one test tube study suggests that lignans may help prevent cancer in ways that are unrelated to estrogen.1 -------------------------------------------------------------------------------- Requirements/Sources The richest source of lignans is flaxseed (sometimes called linseed), containing more than 100 times the amount found in other foods! 11 Flaxseed oil, however, does not contain appreciable amounts of lignans.12 Sesame seed is an equally rich source.44 Other food sources are pumpkin seeds, whole grains, cranberries, and black or green tea.13 -------------------------------------------------------------------------------- Therapeutic Dosages Effective dosages of purified lignans have not been determined. In studies of flaxseed as a source of lignans, flaxseed has been taken at a dose of 5 to 38 g daily. Cooking flaxseed apparently does not decrease the amount of lignans absorbed by the body. -------------------------------------------------------------------------------- Therapeutic Uses A number of preliminary human and animal studies suggest that lignans may be helpful for cancer prevention , particularly of breast and colon cancer, as well reduction of cholesterol. Other highly preliminary research suggests that flaxseeds or lignans may decrease menopausal symptoms 16 and improve kidney function in various types of kidney disease (specifically, lupus nephritis and polycystic kidney disease).17,18 Warning: Flaxseed or other treatments for kidney disease should be taken only under a doctor's supervision, due to the serious nature of these disorders. Despite positive preliminary results in animal studies,14,15 studies in humans have yielded mixed results for improving cholesterol levels.45,46 -------------------------------------------------------------------------------- What Is the Scientific Evidence for Lignans? The most promising use for lignans is in cancer prevention. According to observational studies, people who eat more lignan-containing foods have a lower incidence of breast and perhaps colon cancer.19 This, however, does not prove that lignans are the cause of the benefit, for other factors in these foods, or in the characteristics of the people who consume these foods, may have been responsible. Double-blind, placebo-controlled studies are necessary to prove that a medical treatment provides benefits, and none have yet been reported for lignans. (For information on why this type of study is so important, see Why Does This Database Rely on Double-blind Studies?) Nonetheless, animal studies offer additional support for a potential cancer-preventive or even cancer-treatment effect. Several studies showed that lignan-rich foods or lignans found in flax inhibited breast and colon cancer in animals 20,21,22 and reduced metastases from melanoma (a type of skin cancer) in mice.23 Test tube studies have found that flaxseed or one of its lignans inhibited the growth of human breast cancer cells 24 and that the lignans enterolactone and enterodiol inhibited the growth of human colon tumor cells.25 In many of these studies, it isn't clear whether lignans are responsible for the benefit seen, as flaxseeds contain many other substances. Animal and human studies have begun to examine specific lignans, and results seem to confirm that at least some of the positive effects probably come from the lignans themselves;26,27,28 still, until more and better designed trials are done, we will not know lignans' precise effects on the human body, or the precise dose needed to prevent cancer. -------------------------------------------------------------------------------- Safety Issues Women who are pregnant or breastfeeding should avoid high intake of flaxseed or purified lignans. One study found that pregnant rats who ate large amounts of flaxseed (5% or 10% of their diet), or a purified lignan present in flaxseed, gave birth to offspring with altered reproductive organs and functions, and that lignans were also transferred to the baby rats during nursing.36 In humans, eating 25 g of flaxseed per day amounts to about 5% of the diet.37 High intake of lignans may not be safe for women with a history of estrogen-sensitive cancer, such as breast cancer or uterine cancer. A few test tube studies suggest that certain cancer cells can be stimulated by lignans such as those present in flaxseed.38 Other studies found that lignans inhibit cancer cell growth.39 As with estrogen, lignans' positive or negative effects on cancer cells may depend on dose, type of cancer cell, and levels of hormones in the body. If you have a history of cancer, particularly breast cancer, talk with your doctor before consuming large amounts of flaxseeds. Other potential concerns are discussed in the safety section of the Flaxseed article. |
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