一种基于Z-Curve映射下DNA序列信噪比的快速算法研究

DNA序列信号频谱3-周期特性被认为是用来区分编码区和非编码区的一个重要特征.针对信噪比计算量大的问题,给出基于Z-Curve映射下快速计算信噪比的方法,该方法有效避开计算离散傅立叶变换(DFT),从序列本身直接得到信噪比.实验结果表明,快速算法计算效率是DFT方法的百倍之上,极大减小基因的信噪比计算时间.     

基于指标自动筛选的新疆开孔河流域生态健康评价

生态健康评价对了解区域生态健康状况和促进区域可持续发展具有重要意义,如何自动筛选出能反映生态系统特性的重要指标,是生态健康定量评估的关键问题。基于压力-状态-响应(PSR,Press-State-Response)框架和生态等级网络框架(EHN,Ecological Hierarchy Network),通过文献调研和因果分析建立要素层与指标层之间的交叉联系,构建了生态健康评价"网状"指标体系;在保证指标体系完备性基础上,通过结合主成分分析和熵权法的候选指标权重的客观计算,基于目标优化理论构建了评价指标的自动筛选模型,并基于中选指标计算了新疆开孔河流域2001—2017年生态健康指数(EHCI,Ecological Health Comprehensive Indexes),分析其空间分异和时间变化特征。结果表明:利用所建立的评价指标自动筛选模型,开孔河流域生态健康评价指标由31个候选指标自动筛选出了17个中选指标,用54.8%的指标表达了85.98%的信息,中选的17个指标在干旱/半干旱区域有关文献中应用较多,使用频次比例都在20%以上,其中归一化植被指数(NDVI,Normalized Difference Vegetation Index)、年降水量和植被覆盖度(FVC,Fractional Vegetation Coverage)3个指标的使用频次百分比均超过了50%,说明指标自动筛选模型的合理性;开孔河流域空间分布差异显著,总体上西北高、东南低,东南部和中部绿洲区外围生态健康状况较差,西北部河谷地带和中部两大绿洲区生态健康状况较好;17年来,流域生态质量整体趋于改善,显著改善区域占10.26%,远高于显著退化的1.61%,显著改善区域以孔雀河绿洲最为明显。开孔河流域生态健康的总体好转趋势说明区域生态综合治理取得一定成效。     

SP(0《p《1)上的Ces(a)ro算子是有界的

对0＜p＜1,记SP为具有HP导数的解析函数空间,即SP={f:f∈H(D),f′∈HP},定义f的SP范数为f P = |f(0)| + ‖f′‖P.本文证明了SP(0＜p＜1)上的Ces(a)ro算子的有界性.     

细菌RNA分离试剂盒

Bioscience Technology 2003年7月31页报道：美国Amersham Biosciences公司最近推出GenomiPhi^TM DNA扩增试剂盒。利用这种试剂盒可从有限的生物材料制备高质量的DNA。这是一种简单的等温扩增技术，它不需要使用热循环器。原材料可以是来自全血、颊面拭子、细胞印迹纸、     

Immunological Properties of Recombinant Mycobacterium bovis Bacillus Calmette-Guérin Strain Expressing Fusion Protein IL-2-ESAT-6

The live vaccine Mycobacterium bovis bacillus Calmette-Guérin (BCG) provides variableefficacy against adult pulmonary tuberculosis (TB).Recombinant BCG,expressing either immunodominantantigens or Th1 cytokines,is a promising strategy for developing a new TB vaccine.However,not much isknown about whether the introduction of cytokine and specific antigen genes concurrently into the BCGstrain could improve the immunogenicity of BCG.In this study,a recombinant BCG strain (rBCG) expressingthe fusion protein human interleukin (IL)-2 and ESAT-6 (early secreted antigenic target-6 kDa) antigen ofMycobacterium tuberculosis was constructed.Six weeks after BALB/c mice (H-2~d) were immunizedwith 10~6 colony forming units (CFUs) BCG or rBCG,splenocyte proliferation was determined with MTT[3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide] assay,IL-4 and interferon (IFN)-γproducedby splenocytes were tested by enzyme linked immunosorbent assay (ELISA,) and the cytotoxicity ofsplenocytes from immunized mice to P815 cells (H-2~d) expressing ESAT-6 protein was measured usingCytoTox 96 Non-Radioactive Cytotoxicity Assay.Compared with native BCG-vaccinated mice,rBCG inducedstronger Th1 responses that were confirmed by high lymphoproliferative responses and IFN-γproductionto culture filtrate protein (CFP) or ESAT-6 protein.Moreover,rBCG induced significant enhanced CTLresponses against P815-ESAT-6 cells.Results from rBCG-immunized mice demonstrated that introducingthe il-2 and esat-6 genes into BCG could enhance Th1 type immune responses to ESAT-6.Further investigationis needed by introducing other Th1 cytokines and antigens into BCG to optimize the protective efficacyagainst TB.