小儿医院感染率与医院感染平均暴露日实际意义的探讨

目的　提出医院感染平均暴露日的概念 ,并探讨其应用价值。方法　对小儿医院感染进行回顾性分析。结果　小儿医院感染率与住院天数成正相关 ,缩短住院天数主要通过减少暴露时间影响医院感染率 :医院感染率与医院感染天数无明显相关性 ,分组显示 ,住院时间长的医院感染天数较长 :小儿医院感染率明显低于同期成人 ,小儿医院感染平均暴露日短于成人。结论　医院感染平均暴露日是反映医院感染控制状况较好的指标之一 ,缩短平均住院日不宜作为提高医院感染控制质量的主要方法。     

La dimension de contact et les troubles esthéticophysiognomiques

Dimension of contact is the very moment when meeting with someone. The limits can be precisely defined as an aesthetic moment, i.e. the very moment when someone appears. That is an experience of one's expressivity. One can usually go through this ephemeral moment to reach simple self-continuity. Pathologies of contact may be described at different levels: neurosis, pathological personalities and psychosis.     

多功能验光试镜装置的研制

本文介绍了一种多功能验光试镜装置的设计和应用，通过比较，得出该试镜架比之传统器械具有的优势，在可调散光轴位、可调瞳距、可调镜腿、可调鼻托方面更方便、简捷，且重量轻更加契合人体生理特点，进一步满足临床对眼镜度数的检查需要。最后提出了一些改进意见。     

中长跑和芭蕾舞运动中胫骨应力骨折的比较

胫骨应力骨折（ＳＦ）在芭蕾舞和中长跑运动员中均有一定发病率，作者调查某部新兵２６５人每日５０００米跑步，其胫骨应力骨折病发率为１１．６８％（３１／２６５人），骨折部位多在胫骨中段中后侧。芭蕾舞演员胫骨应力骨折病发率为８％（１５／６０人），骨折部位在胫骨下段前侧。应用新鲜尸体标本作负荷下胫骨多处的应变测定模拟跑步和足跟垫高模仿芭蕾舞时下肢负重位置的应变变化，分别于胫骨中段后侧测得有高压应力和胫骨下段前方有高张应力，此结果与调查中Ｘ线片病变部位相符。作者认为不同的运动使负重时胫骨所处姿势各不相同，而造成胫骨最大应力集中点位置各异，是造成芭蕾舞运动和中长跑运动中应力骨折部位不同的主要原因，预防和治疗工作应根据各自的应力性质和集中点部位来进行防治。     

田径运动员心缩间期的研究

<正> 近年来在运动医学领域中,心缩间期(STI)被认为是评定运动员心脏功能状况的指标之一。为了进一步探讨STI对于评定田径运动员的心脏功能状况的意义,我们进行了下列研究。     

典型办公室内氡浓度水平的时间性变化

目的了解典型办公场所内氡浓度水平随时间变化规律,为开展办公室内氡浓度水平调查或评价提供有效方案。方法选取典型办公室1间,用脉冲电离室测氡仪AlphaGUARD～开展9个月的连续测量,通过对测量数据的统计,分析办公室内氡浓度水平的变化规律。结果在9个月内,办公室内氡浓度的最大日均值、周均值、月均值以及季度均值与相应的最小值比分别为6.27、2.63、1.41和1.09;周末与工作日平均氡浓度的比值为1.17,工作日中上、下班时间段的平均氡浓度比值为0.86。结论办公场所内氡浓度水平虽然随时间变化,但3个月的连续测量均值基本可反映办公室内氡浓度的年度均值。     

Michaelis—Menten兼有一级消除动力学模型平均稳态时的一些特性

本文将Rowland等人的二房室模型中的消除过程扩展成米氏兼一级消除过程。据此,推导出达到稳态浓度的时间、血药浓度-时间曲线下面积和生物利用度的公式;进而得到平均清除率和剂量间的关系以及剂量与平均清除率和血浆浓度呈线性关系的结论。     

水痘发病与季节关系初探

目的　探讨水痘发病与季节的关系。　方法　随机采集我院近 5年住院的 312例水痘患者 ,用圆形分布法统计分析其发病与季节的关系。　结果　 312例水痘患者好发于 4月 2 8日～ 9月 2 4日 ,集中于 7月 11日 ,各月之间比较差异显著 (r=0 .4 4 79,P<0 .0 1)。　结论　水痘好发于春末夏初     

Why do long-distance runners not have more bone? A vital biomechanical explanation and an estrogen effect

Inanimate structures cannot detect and repair their fatigue damage or microdamage, so to minimize it they need more structural material and strength. Living bone handles this matter differently. Bone modeling drifts adapt bone architecture and strength to the loads on bones in ways that tend to keep strains from exceeding a “modeling threshold” range. Strains (or equivalent features) above that threshold switch mechanically controlled modeling ON. Where strains stay below that threshold, this modeling goes OFF. Repeatedly loading-deloading a bone causes microdamage in it, and basic multicellular unit (BMU)-based bone remodeling normally repairs it. Where strains stay below an operational “microdamage threshold,” remodeling can repair whatever microdamage happens for as long as it happens. Strains above that threshold can cause too much microdamage to repair completely and lead to fatigue fractures of trabeculae or whole bones. The modeling threshold normally lies comforably below the microdamage threshold. Since modeling normally adjusts bone architecture to keep strains from exceeding the modeling threshold, this keeps strains below the microdamage threshold, too, and voluntary activities do not cause more microdamage than remodeling can repair. Therefore, long-distance runners do not need more bone mass and strength than nonrunners of comparable age, sex, and body size.     

Radiofrequency Current Ablation of Porcine Right Atrium: Increased Lesion Size with Bipolar Two Catheter Technique Compared to Unipolar Application In Vitro and In Vivo

Interruption of atrial flutter and fibrillation by RF catheter ablation may be favored by large, elongated lesions. We administered RF current in unipolar and bipolar mode in porcine right atrium. Bipolar ablation was performed between the tip electrodes of two serially coupled catheters. With 4-mm tip electrodes in vitro, lesion length increased from a mean (SD) of 7.9 (1.2) mm at 3 mm-interelectrode distance (IED) to 13.3 (3.3) mm at 9-mm IED, but decreased at 12-mm IED due to nonconfluent lesions (P < 0.0001), With 4 mm distal electrodes and 8 mm IED, bipolar lesions were 65% longer than corresponding unipolar ablations. Switching to bipolar mode increased the lesion length more than increasing electrode tip length to 6 mm in unipolar mode. Power and temperature controlled ablation created equally sized lesions. Twelve anesthetized pigs were randomized to unipolar or two catheter bipolar temperature controlled ablation of the right atrial free wall. Bipolar ablation created confluent lesions with endocardial length × width of 13.5 (5.8) × 7.3 (3.7) mm, unipolar ablation 6.4 (2.8) × 4.6 (1.4) mm (P < 0.001 when comparing length and P = 0.013 for lesion width). The atrial lesions in both groups were transmural and extended into hilar lung lesions with maximal depth of 3.0 (1.1) and 2.6 (1.0) mm, respectively (P = 0.44). Five bipolarly and four unipolarly ablated pigs developed right diaphragmal paresis. We conclude that bipolar ablation may be preferable in situations where large, elongated lesions are favorable. The two catheter technique is feasible in porcine right atrium. Both bipolar and unipolar ablation of the porcine right atrial free wall may frequently be complicated by injury to the phrenic nerve and adjacent lung tissue.