期刊文献+
共找到4篇文章
< 1 >
每页显示 20 50 100
(Salen)Ti^ⅣCl2配合物催化环氧化物和环酸酐开环交替共聚 被引量:2
1
作者 李帅 王昱博 +4 位作者 季鹤源 陈崇民 陈晓璐 潘莉 王彬 《高分子学报》 SCIE CAS CSCD 北大核心 2020年第9期1039-1066,共28页
合成、表征了一类具有salen型配体骨架的Ti^Ⅳ配合物(Salen)Ti^ⅣCl2,并研究了它们在催化环酐/环氧开环交替共聚合时的催化性能与催化行为.这些配合物在结构上与传统的(Salen)M^ⅢCl配合物(M=Al,Co和Cr)不同,在配位平面的轴向有2个Cl^-... 合成、表征了一类具有salen型配体骨架的Ti^Ⅳ配合物(Salen)Ti^ⅣCl2,并研究了它们在催化环酐/环氧开环交替共聚合时的催化性能与催化行为.这些配合物在结构上与传统的(Salen)M^ⅢCl配合物(M=Al,Co和Cr)不同,在配位平面的轴向有2个Cl^-基团,不存在空的配位点.以双(三苯基膦)亚胺氯化物(PPNCl)为助催化剂,(Salen)Ti^ⅣCl2配合物可以有效催化常见环酸酐和环氧化物的开环交替共聚合,生成具有完美交替结构的聚酯.聚合活性取决于Salen-Ti^Ⅳ配合物路易斯酸性、配体骨架和单体结构.初步的链引发反应机理研究表明,(salen)Ti^ⅣCl2配合物中的轴向Cl^-基团可与助催化剂中的阴离子发生配体交换而引发聚合反应. 展开更多
关键词 开环交替共聚合 聚酯 钛(Ⅳ)配合物 环酐 环氧化物
原文传递
Isolation and Chemotaxonomic Significance of Chemical Constituents from Rubus parvifolius 被引量:10
2
作者 Quan-xi Mei xiao-lu chen +5 位作者 Xue Xia Zhi-jian Fang Hong-bo Zhou Yu-qiao Gao Wei-bo Dai Ren-wang Jiang 《Chinese Herbal Medicines》 CAS 2016年第1期75-79,共5页
Objective To study the chemical constituents from the roots of Rubus parvifolius. Methods The chemical constituents were extracted and purified by silica gel column chromatography. NMR spectra were used for structural... Objective To study the chemical constituents from the roots of Rubus parvifolius. Methods The chemical constituents were extracted and purified by silica gel column chromatography. NMR spectra were used for structural identification. Results Phytochemical study on the roots of R. parvifolius led to the isolation of one ceramide (1), two anthraquinones (2 and 3), four triterpenoids (4-7), two flavonoids (8 and 9), one fatty acid ester (10), and two sterols (1 1 and 12). Conclusion Compound 1 is isolated from the plants of family Rosaceae for the first time, and compounds 2-5 are isolated from genus Rubus for the first time. Though R. parvifolius shares the same major chemical types (triterpenoid, flavonoid, and anthraquinone) with those of R. alceaefolius, a substituent of R. parvifolius, their individual constituents are different. In addition, R. parvifolius contains ceramide (1) with high concentration, while caffeoylquinic acid reported in R. alceaefolius has not been found in R. parvifolius. Furthermore, the results from our phytochemical study are consistent with the DNA phylogenic relationship between R. parvifolius and R. alceaefolius (two separated subgenera), suggesting that the substitution of the former species with the latter one in folk medicine might not be suitable. 展开更多
关键词 chemical constituents Rubus alceaefolius Rubus parvifolius
原文传递
Cerebral palsy in children born after assisted reproductive technology: a meta-analysis 被引量:7
3
作者 Fang-Fang Wang Tao Yu +2 位作者 xiao-lu chen Rong Luo De-Zhi Mu 《World Journal of Pediatrics》 SCIE CAS CSCD 2021年第4期364-374,共11页
Background Several studies have assessed the association between cerebral palsy(CP)and assisted reproductive technology(ART),but the results remain controversial.We conducted a meta-analysis to evaluate the risk of CP... Background Several studies have assessed the association between cerebral palsy(CP)and assisted reproductive technology(ART),but the results remain controversial.We conducted a meta-analysis to evaluate the risk of CP after ART compared with natural conceptions and to examine CP risk separately in ART singletons,multiples and preterm births.Methods Web-based databases(PubMed,Embase,the Cochrane Library,and Web of Science)were searched until November 22,2020.Studies which compare CP rates after ART with natural conceptions were included.The Newcastle–Ottawa Scale was used to assess the quality of the included studies.Effect estimates were extracted and combined using the fixed-effects or random-effects model depending on the heterogeneity test.Results There were nine studies included in the meta-analysis.The included studies were of moderate or high quality.A significantly higher risk of CP[odds ratio(OR)=2.17,95%confidence interval(CI)1.72–2.74]was found in ART children(n=89,214)compared with naturally conceived children(n=4,160,745).The significantly higher risk decreased when data were restricted to singletons(OR=1.36,95%CI 1.16–1.59)and disappeared when data were restricted to multiples(OR=1.05,95%CI 0.86–1.29)or preterm births(OR=1.53,95%CI 0.66–3.56).Subgroup and sensitivity analyses indicated that the overall results were robust.Conclusions The risk of CP is increased more than two-fold after ART.This increased risk is largely due to increased rates of multiple birth and preterm delivery in ART children. 展开更多
关键词 Assisted reproductive technology Cerebral palsy META-ANALYSIS
原文传递
Polymerase chain reaction-based assays facilitate the breeding and study of mouse models of Klinefelter syndrome
4
作者 Hai-Xia Zhang Yu-Lin Zhou +6 位作者 Wen-Yan Xu xiao-lu chen Jia-Yang Jiang Xiao-Man Zhou Zeng-Ge Wang Rong-Qin Ke Qi-Wei Guo 《Asian Journal of Andrology》 SCIE CAS CSCD 2022年第1期102-108,共7页
Klinefelter syndrome(KS)is one of the most frequent genetic abnormalities and the leading genetic cause of nonobstructive azoospermia.The breeding and study of KS mouse models are essential to advancing our knowledge ... Klinefelter syndrome(KS)is one of the most frequent genetic abnormalities and the leading genetic cause of nonobstructive azoospermia.The breeding and study of KS mouse models are essential to advancing our knowledge of the underlying pathological mechanism.Karyotyping and fluorescence in situ hybridization are reliable methods for identifying chromosomal contents.However,technical issues associated with these methods can decrease the efficiency of breeding KS mouse models and limit studies that require rapid identification of target mice.To overcome these limitations,we developed three polymerase chain reaction-based assays to measure specific genetic information,including presence or absence of the sex determining region of chromosome Y(Sry),copy number of amelogenin,X-linked(Amelx),and inactive X specific transcripts(Xist)levels.Through a combined analysis of the assay results,we can infer the karyotype of target mice.We confirmed the utility of our assays with the successful generation of KS mouse models.Our assays are rapid,inexpensive,high capacity,easy to perform,and only require small sample amounts.Therefore,they facilitate the breeding and study of KS mouse models and help advance our knowledge of the pathological mechanism underlying KS. 展开更多
关键词 40 XXY^(*)mouse 41 XXY mouse Klinefelter syndrome mouse model
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部