分子性

For lactic acid has one asymmetric carbon atom, the mechanical, physical and biological properties of PLA are related to the stereochemistry of lactic acids.

合成聚乳酸的初始物质―乳酸是有手性的分子，使得聚乳酸的机械和物理性能以及生物学性质与乳酸单体的立体异构性有关。

These two series of probes differ in their mechanism of action. The first series exploits the concept of suicide substrate. When the probe is hydrolyzed by the target sulfatase, it will release an intermediate that undergoes elimination to form a reactive quinone methide which in turn reacts with nearby nucleophiles. The second series belongs to an electrophilic reagent which utilizes a cyclic sulfamate moiety serving both as the recognition unit and the trapping device.

这二系列标示分子的主要差异在於其标示机制，第一系列是源自於自杀性受质的概念，利用水解后的中间体会生成高反应性的quinone methide，来达到标示的效果；第二系列则是属於亲核性试剂型，采用环状胺基磺酸衍生物做为辨识端及捕捉机制，预期在其进入酵素的受质结合区后能与酵素催化中心形成共价键结。

The cloned BBE gene sequences were 94.84% identified with the reported BBE genes in GenBank previously. Based on the cDNA sequences of COR and BBE ,two fragments about 400～500 bp from each gene with lower identity among them were cloned. The fusion gene BC (744 bp) is fused by the PCR technique. Then the promoter CaMV 35S driven, containing'forward BC fusion fragments-reverse pdk intron-reverse BC fusion fragments', plant siRNA expression vector were constructed based on the vectors pHANNIBAL and pART27.The work will lay the foundation for breeding a low morphine and high thebaine poppy.

利用blast及分子生物学软件DNAStar对COR和BBE基因的cDNA序列同源性进行分析比较，分别从各基因中筛选和克隆了一段同源性极低、约400～500 bp的片段；并应用重叠PCR法将其拼接成744 bp的融合基因BC，以中间载体pHANNIBAL和植物表达载体pART27为基础，构建了以CaMV 35S启动子驱动的含有"正向BC融合片段- pdk内含子-反向BC融合片段"的ihRNAi植物表达载体，通过转化野生罂粟，初步研究了以COR和BBE基因为靶标的RNAi对内源吗啡合成的抑制效果，为进一步培育低吗啡高蒂巴因的罂粟种质提供了依据。

Interaction between vicinal supramolecules, distance of chiral centers between host and guest molecules and acetone molecule inclused are not important for the chiral recognition between host and guest molecules.

主客体之间手性中心距离的远近以及溶剂丙酮分子等因素，不是影响主客体之间的手性识别的关键因素。

Started from D-tyrosine, we obtained the tetramic acid 96 using Jouin reaction. The assembly of the second fragment 109 was stared from 1,4-butandiol,using asymmetric alkylation reaction developed by Oppolzer as a key step. Coupling of the tetramic acid 96 with 109 provided the key intermediate 110 according to Yoshii\'s procedure. After remove protective group and Sharpless epoxidation, we obtained the key intermediate 113. Its macrocyclization to form the final product is in progress.

本论文的第二章主要对Macrocidin A开展了合成工作，我们从D构型的酪氨酸出发，经过官能团转换；利用Jouin反应生成Tetramic acid 96，另外一个片断从1，4-丁二醇开始经过多步反应生成碘化物104，利用Oppolzer发展的手性樟脑磺酰胺为辅基参与的不对称烷基化反应，引入手性甲基，生成关键中间体109，接着通过Yoshii发展的方法连接96和109生成110，经过Sharpless不对称环氧化反应建立环氧化合物，然后脱去保护基得到关环前体113，分子内的Mitsunobu反应进行关大环反应正在进行之中。

The longer fluorinatd alkyl chain on the three-ring was advantageous to the formation of smectic phase. The mesogens with chiral center located between fluorinated tail and mesogenic core exhibited chiral smectic C phase and other smectic phases when the alkoxyl adhering to the other side of the mesogenic core was of intermediate length.

三环系液晶化合物中较长的氟烷基边链有利于近晶相的形成，且当液晶核另一端的烷氧基链的长度适中时，在氟烷基边链和液晶核之间具有手性中心的液晶分子显示了手性近晶C相和其它液晶相。

In chapter four, the chiral recognition properties of one chiral calix [4] crown ether toward amygdalic acid and dibenzoyl-tartaric acid were studied by 〓H NMR,〓C NMR and UV-vis spectroscopy.

研究结果表明，手性杯[4]氮杂冠醚对二者均有一定的手性识别能力，并发现针对不同的客体，主体以不同的构象与之相互作用，证实分子识别过程中存在构象的变化。

Results:The three groups of P77PMC rats which experienced 30 and less than 30 times of audiogenic seizure and the Wistar control group did not display MF sprouting in dentate gyrus, however, the group of P77PMC rats which experienced 50 times of AGS was found hippocampal MF sprouting into the inner molecular layer of dentate gyrus.

结果：在全身性强直阵挛性惊厥发作次数少于30次的P77PMC大鼠以及对照的Wistar大鼠海马内均未见到MF发芽表现；而在经历50次Ⅳ～Ⅴ级听源性惊厥发作的一组P77PMC大鼠海马内观察到了MF发芽的现象，在海马齿状回内分子层内见到Timm染色呈棕黑色颗粒异常分布的MF末梢。

In this study, nine aspects had been carried out, which included the condition optimization of inducing silkworm asexual reproduction; the effective technique of obtaining unfertilized eggs from virginal moth; the investigation of asexual reproductive genetic resources on bivoltine silkworm races; the creating of bivoltine female asexual reproductive lines; the genetic effect analysis of silkworm asexual reproductive character; the eggs protein study on different female lines; growing and developing comparison between asexual reproductive line and its sexual parent; RAPD study on asexual reproductive character; the utilization of asexual reproductive lines.

本论文主要研究内容包括：家蚕无性繁殖诱导条件的优化；从家蚕处女蛾获取未受精卵的实用技术研究；二化性家蚕品种无性繁殖特性的遗传资源调查；二化性雌蚕无性繁殖系的构建；家蚕无性繁殖性状的遗传效应分析；家蚕无性繁殖品种的蛋白质研究；家蚕无性繁殖品种与其两性亲本生长发育对比研究；控制家蚕无性繁殖性状的基因的RAPD分子标记探索以及家蚕无性繁殖系的利用研究等九个方面，取得的主要结果如下

Random amplified polymorphic DNA markers were used to measure genetic diversity and genetic structure of 150 individuals from 5 natural populations of Carya cathayensis. 252 loci were identified from 20 RAPD primers, out of which 168 loci were polymorphic and accounted for 66.7% of the total genetic diversity at species level.

利用随机扩增多态性DNA分子标记技术，分析了山核桃5个天然居群150个个体的遗传多样性和遗传结构，20条10bp的随机引物共扩增出252个位点，其中，多态性位点168个，多态位点百分率为66.7%。

The labia have now been sutured together almost completely.The drains and the Foley catheter come out at the top.

此刻阴唇已经几乎完全的缝在一起了，排除多余淤血体液的管子和Foley导管从顶端冒出来。

To get the business done, I suggest we split the difference in price.

为了做成这笔生意，我建议我们在价格上大家各让一半。