SqlServer数据库中聚集索引的用法

随着计算机网络的飞速发展,与数据库相关的系统住越来越多的领域被应用,数据库设计变的越米越重要起来。本文就针对数据库中的聚集索引进行阐述。通过对聚集索引的定义,它与非聚集索引的区别,以及如何选择设置聚集索引等问题,进行了逐一的说明。并列举出在相同的SQL语句下,不同的聚集索引设置,对数据库性能的影响。     

Amino Acid Export in Plants: A Missing Link in Nitrogen Cycling

T The export of nutrients from source organs to parts of the body where they are required (e.g. sink organs) is a fundamental biological process. Export of amino acids, one of the most abundant nitrogen species in plant long-distance transport tissues (i.e. xylem and phloem), is an essential process for the proper distribution of nitrogen in the plant. Physiological studies have detected the presence of multiple amino acid export systems in plant cell membranes. Yet, surprisingly little is known about the molecular identity of amino acid exporters, partially due to the technical difficulties hampering the identification of exporter proteins. In this short review, we will summarize our current knowledge about amino acid export systems in plants. Several studies have described plant amino acid transporters capable of bi-directional, facilitative transport, reminiscent of activities identified by earlier physiological studies. Moreover, recent expansion in the number of available amino acid transporter sequences have revealed evolutionary relationships between amino acid exporters from other organisms with a number of uncharacterized plant proteins, some of which might also function as amino acid exporters. In addition, genes that may regulate export of amino acids have been discovered. Studies of these putative transporter and regulator proteins may help in understanding the elusive molecular mechanisms of amino acid export in plants.     

氨基膦酸螯合树脂应用现状

介绍了氨基膦酸树脂的物理化学性质,综述了氨基膦酸树脂应用于吸附分离重金属,稀土金属及作为吸附剂的研究现状,并展望氨基膦酸树脂的应用前景。     

新疆迪西型鹰嘴豆中脂肪和蛋白质组分的研究

[目的]提取新疆产地的迪西型鹰嘴豆的油脂,测定脂肪酸含量及组分,并测定迪西型鹰嘴豆的分级蛋白和蛋白质氨基酸组成.[方法]以新疆产地的迪西型鹰嘴豆为试验材料,提取其种仁油脂.用气相色谱-质谱法测定脂肪酸的含量及组分;采用微量定氮法和分级提取法测定粗蛋白和分离蛋白,并对蛋白质中的氨基酸组成进行了分析.[结果]鹰嘴豆中油脂含量高(18.2%),油脂以不饱和脂肪酸油酸、亚油酸为主要成分,占脂肪酸总量80%以上,饱和脂肪酸含量较低.鹰嘴豆中粗蛋白质含量平均为23.71%,以球蛋白和清蛋白为主,占蛋白质总量的80%以上,而谷蛋白、醇溶蛋白含量较低.其蛋白质均含18种氨酸酸.属完全蛋白质.谷氨酸含量最高,占蛋白质的15.8%;天冬氨酸含量占10.7%;此外还有精氨酸(9.30%)、亮氨酸(7.56%)和赖氨酸(6.34%);其次为苯丙氨酸、丙氨酸、缬氨酸、异亮氨酸;色氨酸、蛋氨酸和胱氨酸含量最少.鹰嘴豆中必需氨基酸含量丰富.[结论]新疆迪西型鹰嘴豆是一种不饱和脂肪酸含量很高;氨基酸含量丰富的豆类作物.     

稀土氨基酸配合物的药学研究进展

近年来,稀土氨基酸配合物因其优异的物理化学性能被广泛的应用在光学、生物工程和医学等方面。稀土氨基酸配合物在药学中的应用极大地推进医学与农业的发展和创新。医药方面,大量实验研究证明稀土氨基酸配合物能抑制癌症、肿瘤细胞的生长,可以用作癌症肿瘤病人的化疗药物;稀土氨基酸配合物可以抑制细菌、真菌的生长,治疗某些细菌真菌引起的疾病;稀土氨基酸配合物可以针对性的选择、改变DNA结构,从而治疗某些基因问题产生的疾病。农业上,稀土氨基酸配合物作为农药,既可直接提高农作物的产量,同时也能抑制真菌类的生长,间接促进农作物生长。     

Synthesis and Characterization of Lanthanum Complexes with Amino Acid Schiff Base

Ｉｎｔｈｅｌｉｖｉｎｇｂｅｉｎｇｓ ,ｃａｌｃｉｕｍｉｏｎｐｏｓｓｅｓｓ ｅｓｍａｎｙｋｉｎｄｓｏｆｉｍｐｏｒｔａｎｔｂｉｏｌｏｇｉｃａｌｆｕｎｃｔｉｏｎ .Ｔｈｅｒａｄｉｕｓａｎｄｔｈｅｃｏｏｒｄｉｎａｔｅａｃｔｉｏｎｏｆｌａｎ ｔｈａｎｕｍｉｏｎａｒｅｓｉｍｉｌａｒｔｏｔｈａｔｏｆｃａｌｃｉｕｍｉｏｎ .Ｃｏｎｓｅｑｕｅｎｔｌｙ ,ｌａｎｔｈａｎｕｍｉｏｎ ,ｗｈｉｃｈｅｎｔｅｒｓｔｈｅｂｏｄｙ ,ｗｉｌｌｒｅｐｌａｃｅｃａｌｃｉｕｍｉｏｎａｎｄｓｈｏｗａｓｅｒｉｅｓｏｆｂｉｏｌｏｇｉｃａｌｅｆｆｅｃｔｓ…     

氨基膦酸树脂对钇的吸附及机理

氨基膦酸树脂 (APAR)对钇 ( )的吸附在 p H=5 .0时最佳。静态饱和吸附容量为 14 3mg/ g树脂 ;用 2 .0～ 4 .0 m ol· L- 1 HCl作解吸剂 ,解析率为 90 % ;测得吸附速率常数 k2 98=1.81× 10 - 5s- 1 ;等温吸附服从 Fre-undlich经验式 ;吸附热力学函数△ H°=1.32 k J· m ol- 1 ;吸附机理表明 ,APAR功能基上的 N、 O与 Y3 发生配位键合。     

稀土氨基酸配合物的研究情况分析

系统分析了 1991～ 2 0 0 1年间发表的近百篇有关稀土与氨基酸配合物的文献 ,主要讨论作者国籍、刊物、机构、内容和方向等方面的问题。中国的科研人员对稀土氨基酸二元配合物的合成、性质、结构进行了系统的研究。从 90年代末开始 ,研究朝着稀土 氨基酸 过渡金属异核配合物和以氨基酸为配体的高pH值下镧系 羟基自组装配合物的方向发展     

氨基膦酸树脂吸附铈的研究

研究了铈(Ⅲ)在氨基磷酸树脂上的吸附行为。试验结果在pH5.0时,静态饱和吸附容量为197mg/g干树脂;用2mol.L-1HCl洗脱,洗脱率为98.1%;表观速率常数k298=2.71×10-5s-1;等温吸附服从Freundlich经验式;吸附反应中的△Ho=50.0kJ.mol-1,△So=286J.mol-1.K-1,△Go=-35.1kJ.mol-1。树脂功能基与Ce3+的配比为2∶1;并用红外光谱探讨了树脂与铈的成键。     

复合氨基酸稀土元素螯合物的生产和应用研究进展

本文总结了国内外复合氨基酸稀土元素螯合物生产工艺的研究和进展情况以及降本增效的综合利用措施,对农作物施用氨基酸稀土元素螯合物的方法作了阐述.使用结果表明复合氨基酸稀土元素螯合物具有用量少、成本低、回报率高的特点,不但能提高农作物的产量,改善品质,还能有效起到灭菌、杀虫、除草、降低农药残留量的作用,是很有发展前途的新型肥料.     

Studies on the Adsorption of Amino Methylene Phosphonic Acid Resin for Holmium（Ⅲ）

Chelateresincontainingoxygen ,nitrogen ,sul phurandphosphorusatomshasthecapabilityofcoordi natingdirectlywithmetalionsandithasbecomemoreandmoreactiveresearchareainrecentyears[1～ 8] .Aminomethylenephosphonicacidresin (APAR)isanovelchelateresinandcontainsafunctionalgroupof[-NH -CH2 -PO(OH) 2 ],whichpossessesnotonlyprotonthatcanexchangewithcation ,butalsooxygenandnitrogenatomsthatcancoordinatedirectlywithmetalions .Therefore ,ithasquitealotofadvantagessuchashighadsorptioncapacity ,easyregene…     

SGD: Saccharomyces Genome Database

OBJECTIVE: To determine prevalence of HIV infection and risk behaviors in commercial sex workers (CSWs), drug users, and prisoners in Sindh, Pakistan. METHODS: A medical clinic was established in a "red-light" district of Karachi. Eighty-one CSWs who registered at the clinic between November 1993 and June 1994 were provided HIV counseling and testing and administered a risk factor questionnaire. Next, 316 male drug users were tested for HIV-1 antibody from April to July 1994. Finally, a voluntary serosurvey of HIV-1 and HIV-2 and risk behaviors of 3525 prisoners in Sindh was conducted between July 1994 and December 1994. Abbott Recombinant HIV third-generation enzyme-linked immunosorbent assay (ELISA) and confirmatory testing with Western blot analysis were used in all three groups. RESULTS: None of 81 CSWs tested for HIV-1 antibody were positive. None of 316 drug users tested positive for HIV-1 antibody. Of 3441 male prisoners, 1 was HIV-1 infected, and of 84 female prisoners, 1 was HIV-1 infected. No prisoner was positive for HIV-2 antibody. DISCUSSION: The prevalence of HIV in CSWs, drug users, and prisoners in Sindh is low at present. Intervention programs implemented at this stage can make an impact in HIV prevention.     

硫酸钆与水杨醛氨基酸Schiff碱配合物的研究

用硫酸钆与水杨醛氨基酸Ｓｃｈｉｆ碱，在水溶液中反应，合成了五种新的配合物，通式为Ｇｄｍ（ＳａｌＡＡ）ｎ（ＳＯ４）ｐ·ｘＨ２Ｏ（式中Ｓａｌ＝水杨醛、ＡＡ＝甘氨酸、Ｌ谷氨酸、Ｌ蛋氨酸、Ｌ胱氨酸和Ｌ赖氨酸，ｍ＝１～４，ｎ＝１～２，ｐ＝０、１、２，ｘ＝３、８、１２）。通过元素分析、摩尔电导、红外光谱、荧光光谱、紫外－可见光谱、差热热重分析对合成配合物的组成、性质进行了研究。     

PEDB: the Prostate Expression Database

Naloxone is generally considered to be a pure antagonist, but it may produce several behavioral effects, such as hyperalgesia or stimulation of respiration. We studied the effect of naloxone on gastric emptying and gastrointestinal transit in rats. Six to eight Wistar rats (200-250 g) were used for each experiment. Either saline or naloxone (0.01-10 mg/kg) was injected intraperitoneally at 0 min. At 30 min, radiolabeled saline or milk 1 mL was infused into the stomach. At 60 min, gastric emptying and gastrointestinal transit were calculated by measuring the radioactivity in the gastrointestinal tract. Naloxone significantly inhibited gastric emptying of saline (P = 0.002) and of milk (P < 0.05), but not the gastrointestinal transit of either (P > 0.05). Gastric emptying of saline showed a significant peak (P < 0.05) in the dose-response curve at 0.7 mg/kg. Therefore, naloxone significantly inhibits gastric emptying of saline and milk, but not the gastrointestinal transit of either. IMPLICATIONS: Although naloxone is generally considered to be a pure opioid receptor antagonist, it delays gastric emptying of saline or milk, as does morphine in the rat. However, it is uncertain from our results whether naloxone inhibited gastric emptying by antagonizing the effects of endogenous opioids.     

氨基酸对La(Ⅲ)与黄河沉积物相互作用的影响

研究了La3+离子在黄河水中与沉积物的相互作用特性及谷氨酸和酪氨酸对吸附作用的影响。结果表明,黄河水中La3+与沉积物相互作用的吸附等温线是一种台阶型的二级交换等温线,用分级离子交换等温式求出了平衡常数K1和K2。氨基酸对La3+与沉积物相互作用有明显影响,低浓度的氨基酸使La3+与沉积物的交换吸附作用增强;酪氨酸对镧与沉积物的相互作用的促进较谷氨酸大。     

氨基膦酸螯合树脂离子交换色层法分离重稀土的研究

采用离子交换色层法用氨基膦酸螯合树脂对重稀土铥、镱、镥富集物进行动态吸附和淋洗分离研究,考察了淋洗剂浓度、酸度、淋洗液流速、温度等因素对分离的影响。结果表明,在吸附柱中,以0.1mL/(cm2.min)的流速进料时能得到较大的吸附率;在淋洗液流速为0.3mL/(cm2.min)、温度30℃的条件下,用pH=8.0、浓度0.02mol/L的EDTA淋洗重稀土富集物,可实现铥、镱、镥三者的完全分离。     

盐酸和硫酸再生D113树脂的技术指标分析

研究以周期制水量、工作交换容量和酸耗作为衡量指标时,分别用盐酸和硫酸再生D113树脂的最佳工艺条件和2种酸再生效果的比较.结果表明,用硫酸再生D113弱酸树脂比HCI再生有更好技术经济指标.     

WorkPlan: Constraint-Based Database for Work Package Scheduling

A database program called WorkPlan has been created to systematically develop weekly work plans. Such work plans are used by crew foremen in scheduling work packages and allocating available labor and equipment resources. WorkPlan adopts the Last Planner methodology, which implements several lean construction techniques. A week prior to conducting work, WorkPlan guides the user step by step through the process of spelling out work packages, identifying constraints, checking constraint satisfaction, releasing work packages, and allocating resources; then at the end of the week, collecting field progress data and reasons for plan failure. This systematic approach helps the user create quality work plans and learn from understanding reasons for failure. The lean planning philosophy underlying WorkPlan and the functionality of the computer program implementation are detailed in this paper. Various ways of displaying work package data are illustrated. WorkPlan's job-shop scheduling view complements the view traditionally adopted by project management, as is reflected in scheduling tools using the critical-path method.     

The Database of Ribosomal Cross-links: an update

The Database of Ribosomal Cross-links (DRC) was created in 1997. Here we describe new data incorporated into this database and several new features of the DRC. The DRC is freely available via World Wide Web at http://visitweb.com/database/ or http://www. mpimg-berlin-dahlem.mpg.de/ approximately ag_ribo/ag_brimacombe/drc/