分数阶广义二阶流体管内轴向流动的精确解

研究了分数阶广义二阶流体的管内轴向流动问题 .在欧氏测度下 ,应用R L分数阶微积分算子理论给出了上述问题的精确解 .同时也指出了已有文献结果的错误和不足之处 .结果表明 ,流体粘弹性特征越明显 ,其速度剖面及应力分布对分数阶导数的阶数依赖性越强     

Evaluation and characterization of an endosperm-specific sbeⅡa promoter in wheat

Hexaploid wheat (bread wheat) is widely grown all over the world. Wheat grain, which contains high levels of starch and protein located in the endosperm, is being developed as a 揵ioreactor?using the new gene transfor-mation technology[1]. Some new traits (such as virus and insect resistance) have been successfully introduced into key cereal crops using transgene technology, however, there are only a few reports on the studies of transgene expression in wheat because of technical difficulties…     

GALERKIN ALTERNATING-DIRECTION METHODS FOR NONRECTANGULAR REGIONS FOR THE TRANSIENT BEHAVIOR OF A SEMICONDUCTOR DEVICE

For the transient behavior of a semiconductor device, the modified method of characteristics with alternating-direction finite element procedures for nonrectangular region is put forward. Some techniques, such as calculus of variations, isoparametric transformation, patch approximation, operator-splitting, characteristic method, symmetrical reflection, energy method, negative norm estimate and a prior estimates and techniques, are employed. In the nonrectangular region case, optimal order estimates in L2 norm are derived for the error in the approximation solution. Thus the well-known theoretical problem has been thoroughly and completely solved.     

可溶性CD40配体与冠脉病变的相关性研究

目的：通过分析可溶性细胞表面分化抗原40配体（sCD40L）水平与冠脉病变的关系，探讨其在冠心病发病中的意义。方法：经冠脉造影确诊的冠心病患者，对冠脉病变程度进行分型，ELISA法检测血浆中sCD40L含量，分析sCD40L水平与冠脉病变程度的相关性。结果：CHD组与对照组相比，sCD40L明显增加，且随冠脉病变累计支数越多、病变越严重，sCD40L水平增高越明显。单因素相关分析显示sCD40L水平与病变支数、病变类型呈正相关关系。结论：sCD40L对ACS不稳定斑块有促进作用，通过检测其表达水平，可能对预测动脉粥样硬化的启动和进展、斑块的易损性等提供新的资料，最终可能指导治疗，     

L1Tc non-LTR retrotransposons from Trypanosoma cruzi contain a functional viral-like self-cleaving 2A sequence in frame with the active proteins they encode

A comparative analysis of 40 Trypanosoma cruzi L1Tc elements showed that the 2A self-cleaving sequence described in viruses is present in them. Of these elements, 72% maintain the canonical 2A motif (DxExNPGP). A high percentage has a conserved point mutation within the motif that has not been previously described. In vitro and in vivo expression of reporter polyproteins showed that the L1Tc2A sequence is functional. Mutations within certain L1Tc2A sequences affect the efficiency of the cleavage. The data indicate that the L1Tc2A sequence may be influencing the L1Tc enzymatic machinery determining the composition and level of the translated products. The residues located immediately upstream of the 2A consensus sequence increase the cleaving efficiency and appear to stabilize the relative amount of translated products. These authors contributed equally to this work. Received 26 January 2006; received after revision 11 April 2006; accepted 21 April 2006     

山东鼠尾草属花粉形态的研究及其在分类上的意义

利用扫描电子显微镜首次对山东鼠尾草属(Salvia L.)3种植物的花粉形态进行了观察和研究。结果显示该属花粉为长球形和扁球形，具6沟，外壁具网状雕纹。探讨了花粉形态特征的分类学意义。表明本属花粉粒形状、大小和外壁雕纹可以作为种间分类的依据。     

一种双种群协同多目标粒子群优化算法及应用

针对当前我国油田开采难度大、 经济效益较低等问题, 建立以利润最大化为优化指标, 以年度增油目标、 增液目标、 增注目标为约束条件的多目标油田开采优化模型, 并提出一种双种群协同多目标粒子群优化算法求解该优化模型. 该算法通过双种群协同进化策略扩大搜索空间, 提高算法的全局搜索能力, 并结合Lévy飞行保证种群多样性, 提高算法收敛效率. 实验结果表明, 该算法能有效求解油田开采优化模型, 可优选出满足目标和约束条件的结果.     

Molecular cloning, in vitro expression and enzyme activity analysis of violaxan-thin de-epoxidase from Oryza sativa L.

The violaxanthin de-epoxidase gene was cloned from rice (Oryza sativa subsp. japonica). The full length of the cDNA is 1887 bp, encoding a 446-amino acids protein with the transit peptide of 98 amino acids. The bacterial expression vector pET-Rvde was constructed and the expression quantity of the exogenous protein increased with the induction time by 0.4 mmol/L IPTG. Its molecular weight was similar with that of the native VDE. Western blotting indicated that the expressed protein has immunological reaction with the VDE polyclonal antibody. The absorbance spectrum together with xanthophyll pigments quantification by HPLC demonstrated that the expressed VDE has its enzyme activity, which can de-epoxidate violaxanthin into antheraxanthin and zeaxanthin in vitro.     

三碘苯甲酸和多效唑诱导黄瓜子叶节花分化临界时间的研究

7d龄黄瓜无菌苗完全切除全部下胚轴、1 / 2子叶和顶芽 ,取子叶节分别培养于诱芽和诱花培养基上 ,进行逐日更换培养基试验 .诱导营养芽培养基中培养 1～ 3 d,转入诱花培养基 ,成花率在 1 4%～ 40 % ;4d后再转入诱花培养基 ,成花率显著降低至 7%左右 .诱花培养基中培养 1～ 2 d后转入诱芽培养基 ,成花率仅 7%～1 4% ,培养 3 d或 3 d以上转入诱芽培养基 ,成花率显著升高至 2 7%以上 ,培养 6～ 7d后转入诱芽培养基 ,直接成花率则可达 60 % .结果表明三碘苯甲酸和多效唑诱导黄瓜子叶节花分化的临界时间是 3 d左右 .     

不同采收时间沙枣叶中矿物元素的含量测定

采用微波消解样品,以火焰原子吸收光谱法(FAAS)测定青海不同采收时间沙枣(Elaeagnus angustifolia L.)叶中Na、Mg、K、Ca、Mn、Cu、Fe、Zn 8种矿物元素的含量,为阐明其饲用价值和药理作用提供一定的理论依据.该方法用于沙枣叶样品分析,回收率为93.97%~104.56%.结果显示,青海沙枣叶中富含K、Ca、Mg三种矿物元素,沙枣叶中K、Mn、Mg和Fe的含量在不同采收时间差异明显.