丁基

We screened a set of Lewis base organocatalysts derived from chiral pipecolinic acid and tert-butanesulfinamide for the reduction of-N-Cbz-1- phenylpropenamine, including newly designed ones and some of those previously developed in our lab. However, only moderate stereoselectivities, albeit high yields were obtained.

在本课题组前期研究的基础上，我们筛选并设计了一系列以手性哌啶酸和叔丁基亚磺酰胺为母体的有机小分子路易斯碱催化剂，它们能催化三氯氢硅对-N-苄氧羰基-1-苯基丙烯胺的不对称还原，获得很高的收率和中等的对映选择性，并且具有很好的底物普适性。

First, the preconcentration method of butyltin compounds using sulhydryl cotton was developed, and desorption methods were discussed.

首先研究了疏基棉预富集测定水样中丁基锡化合物的方法。

First, the preconcentration method of butyltin compounds using sulhydryl cotton was developed, and desorption met...

首先研究了疏基棉预富集测定水样中丁基锡化合物的方法。

Expanded MSCs were induced to differentiate into nerve cells withthree different treatment protocol in the prensent study . On the following day, the medium was replaced with preinduction medium consisting of DMEM, 20% FCS, and 10 ng/ml basic fibroblast growth factor. After 24 h, the preinduction medium was removed, the cells were washed twice with PBS, and neuronal induction medium containing DMEM supplemented with 2% DMSO and200 m bu-tylated hydroxyanisole was added. In later experiments, we used DMEM with 5 mM p - mercaptoethanol or sulfo - glycerine as an alternative neuronal induction medium for the same incubation.

将待诱导分化的MSCs按0.4x10~6／ml接种于事先放置有消毒盖玻片的六孔板内制备细胞爬片，分别采用三种不同的方法诱导第2代至10代的MSCs向神经细胞分化，即方法1先用含bFGF的培养基进行预诱导，之后再用含叔丁基对羟基茴香醚，和二甲亚砜的无血清培养基进行诱导；方法2和方法3用B-巯基乙醇和硫代甘油进行预诱导，然后不同浓度的上述物质进行正式诱导。

Two kinds of new intermolecular complex antioxidants 3-(3, 5-di-butyl-4-hydroxyphenyl) propionyl pentaerythritol phosphate and octstearic pentaerythritol tetra- phosphite were synthesized by one-pot and two steps transesterification.

分别采用一锅法和两步酯交换法合成了两种新型分子内复合型抗氧剂，即3-(3，5-二叔丁基-4-羟基苯基)丙酰亚磷酸季戊四醇酯和八硬脂基季戊四醇四亚磷酸酯。

A novel macromonomer,polystyrene capped with thienyl group,which can undergos oxidation coupling polymerization,has been synthesized by anionic polymerization of styrene with butyl lithium as the initiator and 3-bromo-thiophene as the terminator.

以丁基锂为引发剂、四氢呋喃为溶剂，在氮气气氛和-78℃下进行苯乙烯阴离子聚合，并加入 3-溴噻吩作为终止剂，从而合成出末端含噻吩基的聚苯乙烯，它可以进行氧化偶联聚合，是一类新的大分子单体。

Objective: To evaluate the value of double-phase 99Tc-MIBI tomographic imaging and mammography in diagnosis of breast lesions.

目的：分析比较卿99Tc-甲氧基异丁基异腈双时相断层显像与铝靶X线摄影法对乳腺肿块的临床诊断价值。

It was found that the introduction of t-butyl or methoxy group in the triphenylamine subunit could lead to more efficient photoinduced intramolecular charge transfer, thus improving the overall photoelectric conversion efficiency of the resultant DSSC.

研究结果表明叔丁基或甲氧基取代三苯胺基团能够促进分子内电子转移，进而提高染料分子的敏化效率。

The PS-b-PNIPAM-b-PDMA and PS-b-PDMA-b- PNIPAM triblock copolymers can self-assemble into PS-core micelles, which possess a three layer \'onion-like\' structure, with PDMA and PNIPAM blocks forming the inner layers or outer coronas. Using above measurements, we can concluded that PS-b-PNIPAM-b-PDMA triblock copolymer micelles have the double phase transition behavior, while PS-b-PDMA-b-PNIPAM have only one phase transition behavior.2. We synthesized poly(ethylene glycol-b-methacrylic acid)diblock copolymers with three different polymerization degree of PMAA blocks.

但是对于PS-b-PDMA-b-PNIPAM胶束，由于中间亲水嵌段的作用，使PNIPAM的相转变温度提高，且PDMA由于靠近PS内核以及随着外壳PNIPAM的水溶性变差其相转变点降低，因此我们只能看到一个转变过程。2、通过原子转移自由基聚合，我们合成了三种不同PtBMA长度的PEG-b-PtBMA二嵌段聚合物，将叔丁基水解后得到了三种PEG-b-PMAA二嵌段聚合物。

Apple polyphenol extracts had stronger deoxidizing capacity, antioxidant activity and scavenging effects on superoxide an...

苹果多酚提取物具有较强的还原能力和抗氧化活性，对脂质过氧化产生的超氧阴离子自由基具有较强的抑制作用，且在试验浓度范围内其最大抑制率优于同浓度二丁基羟基甲苯的效果。

By the time of its fall, most of the prisoners were writers who had written against the corruptions of the government.

到它被攻陷的时候，里面多数的犯人是写了反对政府贪污文章的作家。

The most obvious variation to ovum morphological character was that the color was changed from light green to sepiaceous in embryonic development, and all the ovums were almost hatched after 96h.

在胚胎发育过程中卵的形态特征最明显的变化是颜色从淡绿到深褐色，卵在发育96h后卵基本全部孵化。