标准化降水指数与有效干旱指数在新疆干旱监测中的应用

基于干旱监测理论,根据新疆测站1961—2010年逐日降水资料,对比分析了基于不同时间尺度(1、3、6、9、12、24个月)标准化降水指标(SPI)与有效干旱指数(EDI)对干旱监测的有效性与实用性。结果表明:不论针对短期干旱还是长期干旱,EDI监测能力均明显优于SPI。短时间尺度的SPI受短时间降水影响较大,能反映短时间新疆地区的干旱变化特征;随时间尺度的增加,SPI对短时间降水的响应能力较差,但仍可反映长时间序列下明显的干旱变化趋势。与SPI相比,EDI能够很好地反映出短期干旱和当时降水量的影响;同时能够随时间迁移,给每日降水量分配以不同权重,考虑前期降水量对当前干湿状况的影响。相关研究结果可为湿润区及其他气候区洪旱灾害监测提供重要理论依据。     

稀土元素Ce对热挤压变形Al-Mg合金组织与性能的影响

为了确定稀土元素Ce在Al-Mg系合金中的作用,向Al-4％Mg合金中加入不同含量的Ce,研究了Ce对合金显微组织和力学性能的影响。显微组织观察结果表明,加入0.3％～1．0％的Ce不仅可细化Al-4％Mg系合金的晶粒,同时也可改变合金中析出相的类型。拉伸试验结果表明,随着Ce的加入,挤压变形Al-4％Mg系金的室温抗拉强度和屈服强度均有所提高,其中当Ce的加入量为0．6％时,合金的强度最高,与未添加稀土元素的Al-4％Mg合金相比,可使抗拉强度提高近20％,屈服强度提高约16％。室温拉伸断口SEM分析结果表明,挤压变形Al-4％Mg系合金均表现出典型的韧性断裂特征。     

融合内容和服务的未来网络体系架构

互联网难以适应其通信模式由主机为中心向以内容和服务为中心的转变,从而提出了融合内容和服务的未来网络体系架构(Content and Service Aware Network:CoreNet)。CoreNet基于面向内容和服务的设计理念,并通过灵活的协议栈"腰"设计允许应用显式地表达它们的通信意愿,使得网络能感知不同应用模式并进行优化处理。同时,通过网络内置缓存和高效任播路由,提升内容分发和服务获取的效率,适应未来人机物三元融合创新应用的需求。     

Large scale identification of genes involved in cell surface biosynthesis and architecture in Saccharomyces cerevisiae

The sequenced yeast genome offers a unique resource for the analysis of eukaryotic cell function and enables genome-wide screens for genes involved in cellular processes. We have identified genes involved in cell surface assembly by screening transposon-mutagenized cells for altered sensitivity to calcofluor white, followed by supplementary screens to further characterize mutant phenotypes. The mutated genes were directly retrieved from genomic DNA and then matched uniquely to a gene in the yeast genome database. Eighty-two genes with apparent perturbation of the cell surface were identified, with mutations in 65 of them displaying at least one further cell surface phenotype in addition to their modified sensitivity to calcofluor. Fifty of these genes were previously known, 17 encoded proteins whose function could be anticipated through sequence homology or previously recognized phenotypes and 15 genes had no previously known phenotype.     

Apolipoprotein E*3-Leiden transgenic mice as a test model for hypolipidaemic drugs

PURPOSE: We report an investigation into the distribution of proteoglycans (PGs) in normal, organ-cultured and dextran-treated human corneas. METHODS: Immunogold labeling was carried out at the electron microscope level to localize keratan sulphate (KS), chondroitin sulphate (CS), and heparan sulphate (HS) PGs. RESULTS: High levels of labeling for CS was found in the epithelium, endothelium, and keratocytes, with light labelling present in the basement membranes and the corneal stroma. Labeling for HS was present in the epithelium, endothelium, and keratocytes, with intense labeling present at the endothelium/Descemet's membrane interface and the epithelium/Bowman's layer interface. Large filaments were also observed in these regions in cuprolinic blue-stained specimens. Keratan sulphate was present at high levels in the stroma and the basement membranes with low levels present within the keratocytes, epithelium, and endothelium. The pattern of KS labeling along the collagen fibrils in the stroma sometimes showed evidence of periodicity. Organ-cultured corneas had extensive collagen-free "lakes," the interior of which immunolabeled positively for KS and showed staining with cuprolinic blue. The lakes were greatly reduced in the dextran-treated samples. CONCLUSION: This investigation determined the ultrastructural distribution of KS, CS, and HS PGs in human cornea and showed that organ culture is associated with a change in distribution of stromal PGs.     

Paget''s disease of bone

The protein encoded by ras and src protooncogenes are frequently activated in a constitutive state in human colorectal cancer. In this study, we investigated the effect of oncogenic p21ras and Py-MT/pp60c-src on the synthesis of syndecan-1, a membrane anchored proteoglycan playing a role in cell-matrix interaction and neoplastic growth control. To this end, we used Caco-2 cells transfected with an activated (Val-12) human Ha-ras gene or the polyoma middle T (Py-MT) oncogene, a constitutive activator of pp60c-src tyrosine kinase activity. As compared to control vector-transfected Caco-2 cells, both oncogene-transfected cells exhibited: (1) a decrease in syndecan-1 specific activity; (2) a decrease in size and sulfation of syndecan-1 ectodomain glycosaminoglycan side chains; and (3) an active heparanase specifically degrading the heparan sulfate chains. In conclusion, the tumorigenic progression induced by oncogenic p21ras or Py-MT/pp60c-src is associated with marked alterations of syndecan-1 at the post-translational level.     

茶树菇与鸡腿菇原生质体融合及再生

研究茶树菇与鸡腿菇原生质体制备、融合及再生。以菌龄4d 的菌丝体为原料,采用1% 果胶酶和1% 蜗牛酶混合酶液(体积比1:1),酶解4h,酶解温度为30℃,pH6.0 的0.6mol/L 甘露醇溶液为渗透压稳定剂,制备得到茶树菇与鸡腿菇原生质体。两种原生质体融合的最佳条件为：使用35% 聚乙二醇(PEG4000)和0.2mol/L CaCl₂ 溶液(pH10)为助融剂,30℃融合30min。利用灭活原生质体作为标记筛选出融合子,融合的细胞在培养基中实现再生,通过菌落表型的比较和拮抗实验验证再生出的为融合子。