检索结果-南通市图书馆

Tris(5-acetyl-3-thienyl)methane(TATM) forms 2/1(host/guest) inclusion compounds with cyclohexanone and cyclooctanone,but 1/1 inclusion compound with *** crystal structures of these compounds have been studied by X-ray crystallography. The cyclohexanone clathrate crystallizes in a triclinic unit cell of dimensions a = 8.6479(5),b = 10.2617(4),c = 12.8643(5) A,a = 78.925(3),β= 72.601(4),γ= 84.466(4)°,V = 1068.2(1) A,Z = 2,

关键词：

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

MR成像测量眼内肿瘤的大小在预测视网膜母细胞瘤筛板后视神经侵犯和广泛脉络膜浸润中的诊断准确性

引用

国际医学放射学杂志 2016年第4期 439-440页

作者： M.C.De jong F.j.S.van der Meer S.L.Gricke h.j.brisse P.Galluzzi P.Maeder 戴群瑶 Department of Radiology and Nuclear Medicine VU University Medical Center

摘要目的评估视网膜母细胞瘤MR成像测量眼内肿瘤的大小与预测组织病理学确定的转移危险因素(筛板后视神经侵犯和广泛脉络膜浸润)的相互关系。材料与方法本回顾性多中心研究获得伦理委员会批准并免除知情同意。连续纳入1993年—2014年期... 详细信息

摘要目的评估视网膜母细胞瘤MR成像测量眼内肿瘤的大小与预测组织病理学确定的转移危险因素(筛板后视神经侵犯和广泛脉络膜浸润)的相互关系。材料与方法本回顾性多中心研究获得伦理委员会批准并免除知情同意。连续纳入1993年—2014年期间370例视网膜母细胞瘤病人

关键词：视网膜母细胞瘤眼内肿瘤视神经脑神经脉络膜葡萄膜诊断准确性成像测量筛板塔板 MR

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Investigation of side chain liquid crystal polymers bearing cholesterol and bile acid derivatives

引用

合成化学 2004年第Z1期12卷 79-79页

作者： Stephen Freiberg Franεois brisse C. Géraldine Bazuin Département de chimie Université de Montréal C. P. 6128 succursale Centre-ville Montreal (QC) CanadaH3C 3J7. Département de chimie Université de Montréal C. P. 6128 succursale Centre-ville Montreal (QC) CanadaH3C 3J7. Département de chimie Université de Montréal C. P. 6128 succursale Centre-ville Montreal (QC) CanadaH3C 3J7.

Cholic acid (or 3a,7a,12a-trihydoxyl-5a-cholan-24-oic acid) and lithocholic acid (or 3a-hydroxyl-5a-cholanic-24-oic acid) are commonly occurring bile acids synthesized from cholesterol in the liver in mammals. They all possess a steroid skeleton containing four rings, three with six carbons and one with five carbons. The transformation of cholesterol to cholic acid results in two major structural changes that affect the steroid skeleton. The first is the hydrogenation of the double bond between C5 and C6 and the second is a conformational flip of ring A from the 5a-position to the 5a-position. In addition, one or more hydroxyl groups are added to the steroid skeleton. Outside of the ring system, C24 is converted from a saturated alkyl to a carboxylic acid *** chain polymers based on cholesterol moiety have been made as reported in the *** bile acids and cholesterol are all in the family of steroid molecules, it is of interest to investigate whether bile acids may also act as mesogenic ***, flexible spacer groups with 10 carbons are introduced between bile acid skeleton and the poymerizable double bonds. The monomers and polymers are compared with cholesterol and dihydrocholesterol monomers and polymers with the same spacers. Dihydrocholesterol is chosen to investigate the influence of the double bond in the formation of LC, given that both cholesterol and dihydrocholesterol have a planar structure but there is no double bond in the latter. These monomers and their corresponding polymers were characterized for their liquid crystalline (LC) properties by differential scanning calorimetry (DSC), polarizing optical microscopy (POM) and X-ray *** was found that only the compounds bearing the planar cholesterol moieties possess LC phases. It is concluded that the 5a-configuration between the first and second cycles on the steroid skeleton of bile acids does not favor proper alignment of the rigid part of the bile acid moieties.

关键词： bile acids, liquid-crystalline polymers, X-ray

来源：