The free radical oxidation of the tetrahydrocannabinols

Summary The free radical oxidation of ¹ and ⁶-tetrahydrocannabinol has been examined by spin trapping techniques and intermediates that would lead to cannabinol have been trapped. The 1st step in the oxidation of ¹-THC involves the removal of 3-H, while for ⁶-THC, either 2-H or 5-H. Intermediates were isolated which could be pyrolysed to the diene and cannabinol.     

基于Agent的农田生态细胞自动机模型

提出一种基于Agent的细胞自动机(CA)演化模型，并采用整体建模仿真的方法，对农田虫害的演化进行了模拟．它采用自底向上的建模思想，利用Agent的局部连接规则，建立复杂系统的整体模型．针对不同环境条件设定相应的仿真参数，可以得到恰当的害虫种群演化结果，有助于农田生态管理的科学决策．同时，农田虫害的管理是预测专家系统的重要应用领域，该模型与专家系统的最终集成，可以提高专家系统的预测能力．     

两种消除Klebsiella pneumoniae重组型质粒的方法

对于工业发酵菌种肺炎克雷伯氏菌(Klebsiella pneumoniae),研究发现有两种消除其重组型质粒的有效方法,一种是连续传代培养,另一种是使用消除剂十二烷基硫酸钠(SDS)。对K.pneumoniae重组菌连续20代传代培养后,发现其质粒具有较高的消除率;而以0.2%SDS复合Ca2+处理K.pneumoniae重组菌,也能有效消除其重组型质粒,且该方法省却了反复的传代培养,能快速得到质粒消除菌,更具简便易操作性。消除了质粒的K.pneumoniae能再次接纳新的质粒,有效避免了因质粒不相容性带来的转化不成功,进而可用作宿主菌积累更多的生理性状。     

高位钻孔瓦斯抽采参数优化设计

基于采空区覆岩裂隙分布规律、覆岩裂隙瓦斯流动规律和高位钻孔抽采技术研究现状,从覆岩"竖三带"、"O"形圈和U型通风条件下采动裂隙瓦斯流动规律出发,找出高位钻孔的理论合理布置区域,指出工作面后方50m范围内覆岩裂隙发育状况是高位钻孔层位设计的关键,针对祁南煤矿32煤层的特点,结合现场采用数值模拟方法模拟不同开采速度条件下覆岩裂隙发育规律,优化设计高位钻孔的抽采参数,在34下2工作面和3410工作面的现场试验中,高位钻孔抽采浓度和抽采率得到大大提高,取得了较好的抽采效果,验证了研究的正确性。     

非线性映象的Mann迭代的收敛性与不动点

在可度量化拓扑线性空间中，讨论一些非线性映象的不动点与Mann迭代序列的收敛性问题，在一定条件下，得到了一些新的结果，推广和发展了Khan,Ghosh及Rhoades等人的工作。     

Novel major archaebacterial group from marine plankton.

Marine bacteria often dominate the plankton biomass and are responsible for much of the cycling of organic matter, but bacterial diversity is poorly understood because conventional identification methods (requiring culturing) miss about 99% of the organisms. Recent advances permit characterization of microbial communities by analysis of 16S ribosomal RNA gene sequences directly from biomass without the need to culture the organisms; such studies from surface ocean samples have found only eubacteria, not archaebacteria (or Archaea), which are profoundly different. Here we report 16S rRNA sequences obtained from Pacific Ocean bacterioplankton samples collected from depths of 100 m and 500 m. Among these we found sequences only distantly related to those of any organisms previously characterized by 16S rRNA sequences, with similarities to the nearest such relatives (extreme thermophiles) approximately the same as those between animals and plants. We suggest that these sequences are from a previously undescribed archaebacterial group that may have diverged from the ancestors of characterized organisms very early in evolution.     

神经网络方法在胃收缩识别中的应用

胃收缩运动在消化过程中起着重要作用．传统的测量胃运动的方法是侵 袭性的．本文提出一种运用人工神经网络由体表胃电图（ｅｌｅｃｔｒｏｇａｓｔｒｏｇｒａｍ） 无损识别胃收缩运动的方法．以５个受试者的胃电图作为训练集，另５个受试 者的胃电图作为测试集．以同时检测的与每段胃电图对应的胃腔内压力记录 作为评价标准，运用经过优化的具有单个隐层的反向传播神经网络，以分段 后的每段胃电图的时－频表征作为网络的输入，实验结果表明：识别胃运动静 止期的准确度达９０呢，识别收缩运动期的准确度达９４％．     

导出矩阵与基底的正交化

给出导出矩阵的概念并利用它将Ｒｎ中任意一组基底正交化     

Cornelia de Lange syndrome is caused by mutations in NIPBL, the human homolog of Drosophila melanogaster Nipped-B

Cornelia de Lange syndrome (CdLS; OMIM 122470) is a dominantly inherited multisystem developmental disorder characterized by growth and cognitive retardation; abnormalities of the upper limbs; gastroesophageal dysfunction; cardiac, ophthalmologic and genitourinary anomalies; hirsutism; and characteristic facial features. Genital anomalies, pyloric stenosis, congenital diaphragmatic hernias, cardiac septal defects, hearing loss and autistic and self-injurious tendencies also frequently occur. Prevalence is estimated to be as high as 1 in 10,000 (ref. 4). We carried out genome-wide linkage exclusion analysis in 12 families with CdLS and identified four candidate regions, of which chromosome 5p13.1 gave the highest multipoint lod score of 2.7. This information, together with the previous identification of a child with CdLS with a de novo t(5;13)(p13.1;q12.1) translocation, allowed delineation of a 1.1-Mb critical region on chromosome 5 for the gene mutated in CdLS. We identified mutations in one gene in this region, which we named NIPBL, in four sporadic and two familial cases of CdLS. We characterized the genomic structure of NIPBL and found that it is widely expressed in fetal and adult tissues. The fly homolog of NIPBL, Nipped-B, facilitates enhancer-promoter communication and regulates Notch signaling and other developmental pathways in Drosophila melanogaster.     

导出矩阵与基底的正交化

给出导出矩阵的概念并利用它将Rn中任意一组基底正交化.