oalib
Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
恒定低温对不同品系关玉竹组织抗冷性的影响  [PDF]
王二欢,许永华,张忠宝,徐殿文,奚广生,张连学
中国中药杂志 , 2015,
Abstract: 文章以5种关玉竹为试验材料,对其不同部位过冷点、冰点、过冷度、过渡阶段时间、冷却时间及水分组成进行测定。运用灰色关联度法综合分析其组织抗冷性。结果表明,不同玉竹品系及部位的组织抗冷性有所差异;关玉竹组织含水量与冰点、过冷点有一定相关性,但含水量过低时无法测出过冷点和冰点;不同品系关玉竹组织抗冷性强弱顺序为紫茎长叶>大圆叶>小圆叶>长叶>吉竹1号。
VARIATION IN THE YAK CALPASTATIN GENE (CAST)  [cached]
Yang G., Zhou H., Hu J., Luo Y. and Hickford J.G.H.
International Journal of Genetics , 2012,
Abstract: Calpastatin (CAST) is a specific inhibitor of calpain (calcium-dependent cysteine protease). This study investigated the potential for variation in yak (Bos grennies) CAST. PCR-SSCP analysis of exon 6 of yak CAST revealed three unique patterns (named A-C). Sequencing of the amplicons revealed two nucleotide substitutions. One substitution (c.398G/C) would nominally change the amino acid sequence (p.S133T) of yak calpastatin. The variant sequence A which carried c.398C was the most common in the yaks tested (95.1%). This is the first report that found yak CAST is variable, and as in pigs, sheep and cattle, this variation may affect animal production traits.
Characterization of Interferon-α1 of Yak
GuoHua Chen,HuaiJie Jia,YaDong Zhen,Shuang Zeng,YongXiang Fang,XiaoBing He,ZhiZhong Jing,XuePeng Cai
Journal of Animal and Veterinary Advances , 2012, DOI: 10.3923/javaa.2012.3978.3983
Abstract: The yak (Bos grunniens) is an important grazing livestock in Western of China. In this study, the full length of yIFN-a1 gene was cloned then the recombinant yIFN-a1 was expressed in yeast expression system. In vitro bioactivity of IFN-α1 was determined by inhabition infection BHK cell against Vesicular Stomatitis Virus (VSV). The results showed that cDNA contains an Open Reading Frame (ORF) of 570 base pairs encoding a protein of 189 amino acid (aa) precursor with a signal peptide of 23 aa. The homology of the yIFN-a1 was up to 65.3~94.4% with other species at the amino acid levels. The recombinant yIFN-a1 was recognized in Western blot by mAb against human IFN-α1. The activity unit of the purified recombinant yIFN- a1 protein was 1.16×105 IU mg-1 by against Vesicular Stomatitis Virus (VSV) antiviral assay in vitro. This made a basis for the development of anti-virus medicine of yak in the future.
ECONOMY OF YAK HERDERS
Pema Gyamtsho
Journal of Bhutan Studies , 2000,
Abstract: It is widely accepted that an understanding of theenvironmental and socio-economic conditions of an area is aprerequisite for the identification and formulation ofappropriate research and development strategies. It isimportant to know 'why people do what they do' especially intraditional societies which have remained relativelyunchanged by the forces of modern technologicaladvancement. The general belief that traditional pastoralpractices need to be improved has largely shaped pasturedevelopment policy throughout the world (Sanford, 1983).According to Miller (1995), agricultural policies in theHimalayan countries have generally ignored the role oflivestock in development, and failed to appreciate the efficacyof traditional pastoral systems. Ives and Messerli (1989) dweltat great length on the need to develop policies andprogrammes that are sensitively attuned to, and supportive ofthe local people who are the prime actors at the interface ofman-nature relationship. The need to conduct systematicresearch before introducing innovation in the name ofprogress is further stressed by Goldstein et al. (1990).Sustainable innovations for economic enhancement of thepeople or ecological improvement of the environment in whichthey live can only be introduced if there is a high degree ofrelevance to prevailing local cultural and production practicesand traditions.In the high altitude areas of Bhutan at elevations higher than3000 m above sea level, yak production has been andcontinues to be the main source of livelihood for peopleinhabiting this rugged landscape who are known as Brokpas in central and eastern Bhutan, Jops in Western Bhutan,Lakhaps in West-Central region and Dakpas in the remotegewogs of Merak and Sakteng under Trashigang Dzongkhag.All these names, in one way or other means 'pastoralists' andunderscores the dependence of the people on the pastures(known as Tsadrok and Tsabrok in Eastern and CentralBhutan or Tsamjo in western Bhutan) and the mountains(La). Yak rearing is practiced throughout the northern belt ofthe country extending from Haa in the west to Trashigang inthe east and the production systems vary considerably fromplace to place. Nevertheless, there is no denying that yak isthe lifeline of all these communities and is aptly referred to asthe 'camel of the snows'. It is a multi-purpose animalproviding milk, meat, draught and manure. It also adds to theaesthetic value of the Himalayas. Without it, one cannotimagine how humans could survive in this beautiful buthostile region.This paper describes the yak rearing and production systemprevailing
广西鹰扬关群基性火山岩的锆石U-Pb年龄?及其地质意义  [PDF]
周汉文,李献华,王汉荣,李江,李惠民
地质论评 , 2002,
Abstract: TIMS锆石U-Pb定年结果表明,广西贺州下龙地区鹰扬关群浅变质基性火山岩形成于819±11Ma,表明鹰扬关群火山岩是华南新元古代裂谷盆地中最早的火山活动,并确定了华南震旦系的底界年龄为819±11Ma。桂北地区震旦纪裂谷盆地底部火山岩与其不整合覆盖的花岗岩的年龄非常接近,表明区域在约820Ma经历了非常快速的大规模地壳抬升、去顶和裂谷盆地沉降,支持华南约825Ma地幔柱模式。
Dkk1 Regulates Ventral Midbrain Dopaminergic Differentiation and Morphogenesis  [PDF]
Diogo Ribeiro,Kristina Ellwanger,Désirée Glagow,Spyridon Theofilopoulos,Nina S. Corsini,Ana Martin-Villalba,Christof Niehrs,Ernest Arenas
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0015786
Abstract: Dickkopf1 (Dkk1) is a Wnt/β-catenin inhibitor that participates in many processes during embryonic development. One of its roles during embryogenesis is to induce head formation, since Dkk1-null mice lack head structures anterior to midbrain. The Wnt/β-catenin pathway is also known to regulate different aspects of ventral midbrain (VM) dopaminergic (DA) neuron development and, in vitro, Dkk1-mediated inhibition of the Wnt/β-catenin pathway improves the DA differentiation in mouse embryonic stem cells (mESC). However, the in vivo function of Dkk1 on the development of midbrain DA neurons remains to be elucidated. Here we examined Dkk1+/? embryos and found that Dkk1 is required for the differentiation of DA precursors/neuroblasts into DA neurons at E13.5. This deficit persisted until E17.5, when a defect in the number and distribution of VM DA neurons was detected. Furthermore, analysis of the few Dkk1?/? embryos that survived until E17.5 revealed a more severe loss of midbrain DA neurons and morphogenesis defects. Our results thus show that Dkk1 is required for midbrain DA differentiation and morphogenesis.
Metallothionein in Yak Characterization of Metallothionein-III in Yak (Bos grunniens)
L. Yang,L.P. Zhang,J.P. Wu,M.A. Brown,B. Liu,B.Y. Ma,L. Wang
Journal of Animal and Veterinary Advances , 2012, DOI: 10.3923/javaa.2011.100.105
Abstract: Metallothionein-III (MT-III) as a new member of the Metallothionein (MT) family has specific physiological effects different from known MT-I and MT-II. In this study, the yak MT-III gene coding region was amplified and cloned by RT-PCR from brain tissue of yak using YMT-IIISP1 and YMT-IIISP2 as specific primers. The isolated cDNA sequence of MT-III was 207 bp in length (Genbank Accession, NO, DQ323545) and was subjected to BLASTn searching in NCBI. Results of the search indicate that nucleotide sequences of yak share 98, 97, 96, 92, 91, 90, 89, 88 and 86% sequence similarity with cattle, milk goat, hair goat, pig, sheep, chimpanzee, human, dog and house mouse, respectively. Comparing homologies of MT-III sequences with MT-I and MT-II in yak, we found 69 and 67% homologies, respectively. The MT-III protein was composed of 68 amino acids, including 19 cysteines, similar to the number of cysteines of sheep but not human and mouse which lack the conserved ninth cysteine and have no aromatic amino acids. There were conserved motifs of MTs, such as C-X-C, C-C-X-C-C, C-X-X-C and KKS and specific motifs including MDPE, CPCP in MT-III. This conservation of motifs suggests a conservation of MT-III in molecular evolution. The MT-III in yak had no signal peptide and represented a form of cytoplasmic protein similar to MT-I/II. There were few sheets in secondary protein structures, obvious helices in 39-46th AA and mainly irregular curling in the 2D-structure of MT-III protein. The lack of the conserved ninth cysteine in yak MT-III merits further research.
日粮组成对牦犊牛消化和能量代谢的影响  [PDF]
董全民,赵新全,施建军,王彦龙,盛丽,杨时海
草业学报 , 2012,
Abstract: 在海拔3980m的果洛州大武乡对3头牦犊牛分别饲喂100%的青贮披碱草(A)、40%精料+60%青贮披碱草(B)、60%精料+40%青贮披碱草(C)3种不同日粮,按3×3拉丁方设计了消化代谢试验。结果表明,1)日粮干物质、有机质、粗蛋白和能量消化率差异显著(P<0.05),粗灰分消化率差异不显著(P>0.05),且随日粮中精料比例的增加,各营养成分的消化率逐渐降低;2)日粮C的能量代谢率显著低于日粮A和日粮B(P<0.05),但消化能转化为代谢能的效率差异不显著(P>0.05),其平均转化效率为0.78;3)粪和尿中排出钙差异显著(P<0.05),粪中排出磷差异不显著(P>0.05),而尿中排出磷差异显著(P<0.05);钙存留量随日粮中精料比例的增加而减小,磷存留量在A日粮下最大。以上结果说明牦犊牛对日粮的消化和能量代谢与其组成密切相关,而且表观消化率随日粮水平的提高而降低,其能量转化率低于生长牦牛和成年牦牛。因此,该结果可为牦犊牛的补饲和快速育肥提供科学依据。
关附甲素对实验性心律失常和心肌收缩性的影响  [PDF]
董月丽,陈维洲
药学学报 , 1995,
Abstract: 关附甲素(gfa)浓度为20~3oμg·ml-1时,可以降低无k+高ca2+液灌流离体大鼠心脏诱发vt和vf的发生率。清醒大鼠ivgfa2.5~10mg·kg-1,可依剂量性显著增加北草乌头碱引起室性早搏的用量。清醒犬ivgfa10mg·kg-1,可逆转哇巴因引起vt,并对麻醉犬(10~20mg·kg-1),由ach诱发房颤有明显的抑制作用。gfa10mg·kg-1iv可明显减慢麻醉犬或清醒犬心率,对心肌收缩性(vmax和vpm)只有轻度而短暂的抑制,但对左室收缩压,心搏量和心输出量无明显影响。
一类变分条件下微分方程解的有界性关
刘坤会
自然科学进展 , 2001,
Abstract: 讨论了在某种变分条件下一类微分方程解的有界性,指出了它在随机控制理论中的应用.
Page 1 /100
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.