运动试验Ptfv1异常与左室舒张功能的关系及临床意义

目的 :探讨运动试验诱发心电图 V1导联终末电势 (Ptfv1)异常的临床意义。方法 :以 Ptfv1<- 0 .0 3mm· s及超声心动图 E/ A<1为异常标准 ,对 2 0 5例运动试验 Ptfv1与 E/ A异常发生率的关系进行分析。结果 :在运动试验诱发 Ptfv1异常合并 ST异常组 (n=30 )及单纯 Ptfv1异常组 (n=4 2 )中 ,E/ A异常者高达 90 .0 %及 85.7% ,显著高于运动试验正常组 (n=75) (P<0 .0 0 5)及单纯 ST异常组(n=58) (P<0 .0 0 5)。结论 :运动试验 Ptfv1异常与 E/ A异常 (左心室舒张功能障碍 )有关 ,可作为反映早期左心室舒张功能异常的心电图指标。     

Efficacy of tilt training in the treatment of neurally mediated syncope. A randomized study.

Recurrent neurally mediated syncope represents a common clinical event and a therapeutic challenge. Recently tilt training has been proposed for the treatment of recurrent neurally mediated syncope. To evaluate the efficacy of tilt training in preventing tilt-induced syncope and its feasibility, this controlled, randomized study was undertaken. Sixty-eight consenting patients (25 males and 43 females, mean age 40 +/- 19) with recurrent neurally mediated syncope and 2 consecutive positive nitroglycerin-potentiated head-up tilt tests were randomized to tilt training (35 patients) or no treatment (controls, 33 patients). The tilt training programme consisted of daily 30-min sessions of upright standing against a vertical wall 6 days a week for at least 3 weeks, until a reevaluation tilt test (3 patients of both groups dropped out). On this third head-up tilt test, 19 (59%) of 32 tilt trained patients and 18 (60%) of 30 controls still had a positive test. Treated patients performed a mean number of 15 +/- 7 sessions (median 16) and only 11 patients (34%) did all the programmed sessions. Only 1 patient (3%) discontinued treatment because of intolerance, while all other patients did not perform tilt training adequately, because of poor compliance. Thus, in our study tilt training was not effective in reducing tilt testing positivity rate in patients with neurally mediated syncope. Because of poor compliance, tilt training appears to be a feasible treatment only for highly motivated patients, but not for the majority of patients with recurrent neurally mediated syncope.     

大学生预防性治疗的结核菌素反应强度标准研究

目的 探讨结核菌素反应强度与结核病发病的相关性;提出预防性治疗对象的结核菌素反应标准.方法 对不同结核菌素反应强度的新入学大学生进行4年的结核病发病观察,分析结核菌素反应强度与发病危险性、发病时间的关系,比较不同反应强度预防性治疗对象发病率的变化.结果 26 543名健康学生进行了结核菌素试验和4年的发病观察,反应强度为0～4、5～9、10～14、15～19和≥20 mm或水泡丘疹者的年均结核病发病率分别为12.97/10万、13.34/10万、50.32/10万、167.56/10万和250.21/10万;0～4和5～9 mm反应者头2年发病率很低,第3、4年有所增高,而15～19和≥20 mm或水泡丘疹者头2年发病率很高,随着时间推移有下降趋势.当逐个计算反应强度每增加1 mm及以上反应者的发病率时,15 mm以上的各反应强度者中结核病发病率相似,一直维持在较高水平.PPD反应标准15 mm及以上可以覆盖80.8%的病人,而且病人的发现效率也维持在一个高水平.结论 结核菌素反应强度与结核病发病存在明显正相关,特别在头2年危险比更大;PPD反应≥15 mm或有水泡丘疹阳性者的发病机会明显升高,PPD反应≥15 mm或有水泡丘疹阳性标准能够覆盖80%以上的病人,病人的发现效率也最高.因此以PPD反应≥15 mm或有水泡丘疹作为预防性治疗对象的结核菌素反应标准更为合理.     

含有镍钛合金丝的PET纺织瓣膜有限元分析及体外流体力学测试

目的 利用有限元方法分析径向织入镍钛金属丝的涤纶(polyethylene terephthalate, PET)基纺织瓣膜力学性能,结合体外血流动力学测试,分析金属丝数量和分布形式对PET瓣膜流体动力学性能的影响。方法 使用建模软件构建在径向方向上具有不同数量和分布的金属丝PET瓣膜和无金属丝PET瓣膜三维几何模型;根据文献和实验数据给定PET瓣膜和金属丝的材料属性;使用体外脉动流实验得到PET瓣膜的跨瓣压差曲线作为边界条件;利用有限元分析软件研究瓣膜在心动周期内的应力分布;通过体外脉动流实验评估金属丝瓣膜的流体力学性能。结果 有限元分析结果表明,径向织入镍钛金属丝可以增强对PET纺织瓣膜的支撑作用,金属丝均匀分布的瓣膜在瓣叶腹部区域的支撑力及作用区域随着金属丝数量增加而增大,金属丝分布在两侧位置的情况类似。金属丝的织入一定程度上改善PET瓣膜上的应力集中。脉动流实验结果表明,织入金属丝PET瓣膜开闭形态的稳定性、有效开口面积、反流分数和跨瓣压差等指标均优于无金属丝的纯PET瓣膜。结论 在PET纺织瓣膜的径向方向织入金属丝可以有效减少心动周期内PET纺织瓣膜上的应力集中,降低PET纺...     

Eco-Friendly Incorporation of Crumb Rubber and Waste Bagasse Ash in Bituminous Concrete Mix

The consumption of waste materials in the construction sector is a sustainable approach that helps in reducing the environmental pollution and decreases the construction cost. The present research work emphasizes the mechanical properties of bituminous concrete mix prepared with crumb rubber (CR) and waste sugarcane bagasse ash (SCBA). For the preparation of bituminous concrete mix specimens with CR and SCBA, the effective bitumen content was determined using the Marshall Mix design method. A total of 15 bituminous concrete mix specimens with 4%, 4.5%, 5%, 5.5% and 6% of bitumen content were prepared, and the effective bitumen content turned out to be 4.7%. The effect of five different CR samples of 2%, 4%, 6%, 8% and 10% by weight of total mix and SCBA samples of 25%, 50%, 75% and 100% by weight of filler were investigated on the performance of bituminous concrete. A total of 180 samples with different percentages of CR and SCBA were tested for indirect tensile strength (ITS) and Marshall Stability, and the results were compared with conventional bituminous concrete mix. It was observed that the stability values rose with an increase in CR percentage up to 6%, while the flow values rose as the percentage of SCBA increased in the mix. Maximum ITS results were observed at 4% CR and 25% SCBA replacement levels. However, a decrease in stability and ITS result was observed as the percentages of CR and SCBA increased beyond 4% and 25%, respectively. We concluded that the optimum CR and SCBA content of 4% and 25%, respectively, can be effectively used as a sustainable alternative in bituminous concrete mix.     

904例荨麻疹患者常见过敏原流行特征分析

目的:了解本地区荨麻疹患者常见过敏原的流行情况及变化趋势.方法:对2013年2月1日至2020年3月31日在本院就诊的904例荨麻疹患者19种过敏原特异性IgE(sIgE)筛查结果进行回顾性分析.结果:①sIgE总阳性率74.78％;食物性sIgE阳性率明显低于吸入性(x2=32.50,P<0.01).②不同性别患者s...     

A Community Study of SARS-CoV-2 Detection by RT-PCR in Saliva: A Reliable and Effective Method

Efficient, wide-scale testing for SARS-CoV-2 is crucial for monitoring the incidence of the infection in the community. The gold standard for COVID-19 diagnosis is the molecular analysis of epithelial secretions from the upper respiratory system captured by nasopharyngeal (NP) or oropharyngeal swabs. Given the ease of collection, saliva has been proposed as a possible substitute to support testing at the population level. Here, we used a novel saliva collection device designed to favour the safe and correct acquisition of the sample, as well as the processivity of the downstream molecular analysis. We tested 1003 nasopharyngeal swabs and paired saliva samples self-collected by individuals recruited at a public drive-through testing facility. An overall moderate concordance (68%) between the two tests was found, with evidence that neither system can diagnose the infection in 100% of the cases. While the two methods performed equally well in symptomatic individuals, their discordance was mainly restricted to samples from convalescent subjects. The saliva test was at least as effective as NP swabs in asymptomatic individuals recruited for contact tracing. Our study describes a testing strategy of self-collected saliva samples, which is reliable for wide-scale COVID-19 screening in the community and is particularly effective for contact tracing.