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异头效应与α.β—异头物的稳定性
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作者 曾启华 《遵义师范高等专科学校学报》 1999年第1期74-76,64,共4页
一、引言 D-葡萄糖存在着两种环式结构—α-D-吡喃葡萄糖和β-D-吡喃葡萄糖,两者为C-1差向异构体。吡喃环的C-1位也叫异头位,故这两种构象异构体又称α.β-异头物。当葡萄糖水溶液达到平衡时,α-异头物(以下简称α-体)约占37%,β-异头... 一、引言 D-葡萄糖存在着两种环式结构—α-D-吡喃葡萄糖和β-D-吡喃葡萄糖,两者为C-1差向异构体。吡喃环的C-1位也叫异头位,故这两种构象异构体又称α.β-异头物。当葡萄糖水溶液达到平衡时,α-异头物(以下简称α-体)约占37%,β-异头物(以下简称β-体)约占63%: 展开更多
关键词 效应 异头物 偶极相互作用 平伏键 溶剂化作用 优势构象 立体效应 介电常数 场效应 葡萄糖水溶液
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苷类化合物研究(Ⅰ)——天麻苷类似物的合成 被引量:5
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作者 彭师奇 李立朴 +3 位作者 吴建伟 郑晓敏 程铁明 蔡孟深 《高等学校化学学报》 SCIE EI CAS 1988年第1期47-51,共5页
本文合成了16种天麻苷类似物,测定了它们的^(13)C NMR和~1H NMR。依据NMR数据,这些化合物的端基构型指定为β构型。
关键词 化合 NMR 天麻苷 端基构体 异头物 类似 同型 苯甲醛
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Extraction and clipping repair of a chicken bone penetrating the gastric wall 被引量:1
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作者 Jin-Soo Kim Hyung-Keun Kim +5 位作者 Young-Seok Cho Hiun-Suk Chae Chang-Whan Kim Byung-Wook Kim Sok-Won Han Kyu-Yong Choi 《World Journal of Gastroenterology》 SCIE CAS CSCD 2008年第12期1955-1957,共3页
We report a case of gastric penetration caused by accidental ingestion of a chicken bone in a 42-year old woman with a partially wearing denture. Three days ago, she accidentally swallowed several lumps of poorly-chew... We report a case of gastric penetration caused by accidental ingestion of a chicken bone in a 42-year old woman with a partially wearing denture. Three days ago, she accidentally swallowed several lumps of poorly-chewed chicken. Physical examination disclosed mild tenderness in the periumbilical area. Abdominal Computed tomography (CT) showed a suspicious penetration or perforation of the stomach wall measuring about 3 cm, by a linear radiopaque material at the lesser curvature of the antrum. The end of a chicken bone was very close to but did not penetrate the liver. Endoscopic examination revealed a chicken bone that penetrated into the prepyloric antrum. The penetrating chicken bone was removed with grasping forceps. Five endoscopic clips were applied immediately at the removal site and the periumbilical pain resolved promptly. After removal of the chicken bone, the patient was treated with conservative care for three days, after which she was completely asymptomatic and discharged without complication. To treat gastric penetration by a foreign body, endoclipping can be a useful method in patients with no signs or symptoms of peritoneal irritation. 展开更多
关键词 Gastric penetration Chicken bone Hemoclip
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