用PowerPoint XP设计幻灯片元素动画效果的实践

PowerPoint XP新特性中突出的就是其动画设计功能的加强。文中对新增加的与动画没计相关的功能使用要点结合实际作了较详细的叙述。     

手部创伤性骨关节缺损的处理

治疗手部骨关节缺损常采用植骨内固定、关节融合、关节成形及关节置换等方法．为总结经验，对１９８９年以来１０１例手部创伤性骨与关节缺损进行分析。单纯掌、指骨缺损３９例，行直接短缩对位，克氏针内固定６例，１例发主骨不连；对３３例缺损较大者用自体骨块植入克氏针交叉内固定，部分病例同时植人ＲＢＸ或异体骨粒，１０例发生延迟愈合，余全部正常愈合。骨与关节部分或完全缺损６２例，采用关节成形术４６例，其中以肋软骨移植效果最好，骨膜移植次之，筋膜衬垫或硅胶膜植入法较差；行关节融合术１１例．均达顺利融合；采用自体关节置换５例，均成活，术后关节活动度均＞７０°。我们认为：自体骨块植入克氏针交叉内固定，必要时植入ＲＢＸ骨粒．是治疗手部创伤性骨缺损的有效方法。关节缺损应按关节的重要性，分别采用关节融合术、关节成形术或关节置换术。     

Effects of posts on dentin stress distribution in pulpless teeth.

A finite element analysis was carried out to study the roles of posts in reducing dentin stress in pulpless teeth. Two-dimensional plane strain models of the midlabiolingual section of a human maxillary central incisor were first analyzed. The results showed that the gold alloy post reduced maximal dentin stress by as much as 30%. However, the integrity of the dentin was compromised and the effects of the post were likely to be exaggerated in such models. In an effort to correct for these problems, plane stress models with side plates and axisymmetric models were analyzed. Posts were found to reduce maximal dentin stress by only 3% to 8% when the teeth were subjected to masticatory and traumatic loadings in these latter models. Although posts reduced maximal dentin stress by as much as 20% when the teeth were loaded vertically, teeth such as incisors and canines normally are not subjected to vertical loadings. Thus the reinforcement effects of posts seem to be doubtful in these teeth.     

硫酸多糖对体外人脐静脉内皮细胞损伤的保护作用

研究表明,硫酸多糖体外对多聚阳离子和氧自由基损伤的人脐静脉内皮细胞有保护作用。肝素、硫酸软骨素A抗多聚阳离子损伤作用比同浓度低分子肝素和甘糖酯强。肝素、硫酸软骨素A、甘糖酯抗氧自由基损伤作用优于同浓度低分子肝素。结果显示硫酸多糖有保护血管内皮的作用,其作用可能与所带阴离子基团有关。     

Laparoscopic nephrectomy in a porcine model.

Laparoscopic nephrectomy was performed in 15 male pigs, the procedure was successful in 14. Extraction of the intact kidney through a 5-cm lower abdomen incision was done in 7 animals; complete destruction and evacuation of the kidney was accomplished by a round-knife suction device through a 1-cm port in another 7 pigs. Grossly, the specimen consisted of sausage-like tubular renal tissue and a small amount of tissue debris. Pathology revealed that the glomerular and tubular structures were well preserved, no interstitial hematoma could be found. Four ports were usually used, one 1-cm umbilical camera port, one 0.5-cm port for ureter traction, and two 1-cm working ports along the midclavicular line. All the pigs recovered uneventfully. The average operation time was 3 h 20 min. The application of endo-GIA (United States Surgical Corporation) for renal hilum reduced the operative time to 2 h 20 min. Complications included renal vein tear during endoclip application and cutting in the first case, mild subcutaneous emphysema in 2 cases. This first pig received exploratory laparotomy for the repair and ligation of the renal vein. No more major complications occurred with increasing experience. From this porcine experiment, we conclude that the combination of laparoscopy, a tissue destroyer and an endobag for the entrapment of kidney seem to be a promising technique for clinical nephrectomy.     

凋亡敏感基因在短暂性缺氧再复氧复注血清后的大鼠星形胶质细胞中的表达及其意义

目的研究一种新发现的抗氧化蛋白质--凋亡敏感基因(SAG)在短暂性缺氧再复氧复注血清诱导的细胞坏死和凋亡中的作用.方法用短暂性缺氧再复氧复注血清来诱导原代培养的大鼠大脑皮质星形胶质细胞损伤,用免疫细胞化学方法检测凋亡敏感基因的表达,并作图像分析;用流式细胞仪检测胶质细胞在短暂缺氧再复氧复注血清后不同时间点的凋亡率.结果凋亡敏感基因在缺氧15 min再复氧复注血清5 h后表达最高,在复氧复注血清16 h后恢复至对照组水平;细胞凋亡率在缺氧15 min再复氧复注血清1h时达到最高,而在再复氧复注血清5 h后降至对照组水平.结论凋亡敏感基因具有抗凋亡的作用,可减轻星形胶质细胞的缺血再灌注损伤.     

Visual completion processing in human face perception.

Subjects discriminated whether two sequentially presented human face pictures (S1 and S2) were identical while event-related potentials were recorded to explore the neural basis of visual completion for occluded objects. Four kinds of stimulus trials were employed: S2 and S1 were identical (match-complete); S2 and S1 were identical, but S2 was partially occluded (match-incomplete); S2 was a different face from S1 (mismatch-complete); S2 was different from S1, and was partially occluded (mismatch-incomplete). Incomplete faces enhanced the amplitude of N1 compared with complete faces. The peak latency of N2 elicited by incomplete faces was delayed about 20 ms compared with complete faces. The enhancement of N1 is related to visual completion processing that requires additional time.     

Differential binding kinetics of cholera toxin to intestinal microvillus membrane during development

A complete randomized block design was used to compare the binding kinetics of cholera toxin to developing rat enterocyte microvillus membranes prepared from newborn, 2-week-old, 4-week-old, and adult animals. Saturation-binding isotherms were generated on 16 independent samples (four blocks) under steady-state and reversible conditions. Scatchard analyses suggested positive cooperative binding to a single class of receptors, and the isotherms were analyzed by both the Hill-Waud and Michaelis-Menten functions. Receptor density varied significantly with age (P = 0.013). An abrupt rise in receptor density occurred after the neonatal period and normalized in the adult animal. The half-dissociation constant also varied significantly with age (P = 0.019). Microvillus membranes from suckling animals had a slightly higher apparent affinity than those from weaned animals. Neither receptor concentration nor membrane purity confounded these observations. Whereas age-related changes in apparent affinity correlated with cellular responses, changes in receptor density did not. This study suggests that developmental changes in membrane structure which influence binding affinity but not receptor density may, in part, contribute to the increased sensitivity of suckling rats to cholera toxin exposure.     

Post-synthetic modification in vivo of the major hemoglobin beta chain in the rat

Rat hemoglobins are unusually heterogeneous among mammals. This heterogeneity provides multiple opportunities for asynchronies in synthesis and degradation. We have examined rat hemoglobin turnover after an intravenous injection of 2-14C-glycine. After analyzing incorporation into the seven nonallelic globin chains of adult rats, we found the percentage of the major beta chain decreases over the red cell lifespan while the percentage of one of the minor beta chains increases. This suggests that a post-synthetic modification event converts a portion of the latter into the former.