The Effect of 50 Hz External Electrical Interference on Implanted Cardiac Pacemakers

The effects of injected 50 Hz alternating current on the function of cardiac pacemakers has been observed in 18 patients with implanted unipolar VVI units. Current, in the range 0-600 microA was applied via electrodes attached to the patients' upper body and feet and fed from a specially designed current injection unit at the bedside. Most implanted pacemakers reverted to interference mode in the current range 29-250 microA. At current levels just below the reversion current all units developed irregular and inappropriate pacing. This current level was pacemaker dependent and varied in the range 27-246 microA. The total reversion current depended on the location of the injecting electrodes and on the patients' posture. The sensitivity of the units to injected interference was increased by deep inspiration. Temporary pacing catheters fitted to an additional ten patients were used to monitor the interference voltage which would be sensed by an implanted unit. This voltage was similarly dependent on patient posture and on deep respiration. Current injection has proved to be a safe, controllable and reproducible method of testing the sensitivity of implanted pacemakers to 50 Hz external interference.     

912抗肿瘤作用机理的初步探讨

作者对912的抗肿瘤作用机理进行了初步探讨。观察到912对癌细胞的移植量以及不同的服用时间均表现出不同的抑瘤效应。将服用912后的小鼠的脾细胞与肿瘤细胞混合后再接种,肿瘤生长明显抑制。912对实验肿瘤动物的外周血白细胞分类、巨噬细胞的吞噬功能和E玫瑰花形成也有一定的影响。     

光固化复合树脂修补方法的比较研究

本研究评价了喷砂、氢氟酸(HF)、氢氟酸处理后涂KH-570乙醇液等方法时国产GD光固化复合树脂以及进口VIVADENT复合树脂的修补效果.结果表明:9.6%HF处理国产树脂、喷砂处理进口树脂均获得最大的修补强度,HF KH-570处理方法虽为每种材料中之最小者,但与其它修补方法间无显著性差异.     

Flecainide

Flecainide. Flecainide is a Class IC antiarrhythmic agent whose primary electrophysiologic effect is a slowing of conduction in a wide range of cardiac tissues. It is well absorbed and effective in suppressing isolated premature ventricular contractions (PVCs) or nonsustained ventricular arrhythmia but has only a modest efficacy when electrophysiologic testing is used as an endpoint. Us adverse effect on mortality in the CAST trial suggested a propensity to proarrhythmia-a phenomenon to which the Class IC agents appear particularly prone. Despite the applicability of the CAST study only to patients with a prior myocardial infarction, there has been a shift away from flecainide in ventricular arrhythmia, but the low noncardiac side effect profile of the agent allows for its continued use in a wide variety of supraventricular arrhythmias. ( J Cardiovasc Electrophysiol, Vol. 5, pp. 964–981. November 1994 )     

新螯合剂对铍中毒的解毒和促排效果

本文报道了新蟹合剂8102,S186对铍中毒动物的解毒和促排作用,并与811,DTPA 进行比较,大、小鼠BeSO_4中毒后,给予不同剂量的螯合剂解毒,结果表明,8102,S186对铍中毒动物的解毒效果均优于后两种,对大鼠的解毒作用8102优于S186,但S186对小鼠的解毒作用优于8102。螫合剂对大鼠BeSO_4染毒的排铍效果实验结果证明:各螫合剂的排铍效果强弱:8102>S186>811>DTPA。8102和S186对大鼠急性铍中毒有明显的排铍效果,若染毒前1h 或延迟4h 给药,仍有显著的排铍作用,但低于即刻用药组的效果。8102对亚急性染毒带铍状态亦有较高促排铍的作用。     

硝基化合物还原、氢化的研究 Ⅳ.用Fe~(3+)催化转移氢化3,3′-二硝基-4,4′-二氨基二苯醚

以Fe~(3+)代替Pd-C和Raney Ni为催化剂、水合肼为供氢体、3,3′-二硝基-4,4′-二氨基二苯醚为受氢体、甲醇为溶剂,进行催化转移氢化反应,产物3,3′,4,4′-四氨基二苯醚(TADPO)质量好,得率可达80%。此外,还对反应温度、时间、以及水合肼、催化剂、溶剂用量,水合肼浓度、催化剂重复使用等影响因素进行了研究,获得了较佳工艺条件。本法制得的TADPO与均苯四甲酸二酐缩聚可制得性能良好的聚眯唑吡咙。     

Respiratory symptoms associated with the use of azodicarbonamide foaming agent in a plastics injection molding facility

Respiratory health variables were studied cross-sectionally in 227 employees of a plastics molding facility where numerous complaints had been apparently associated with the use of azodicarbonamide foaming agent in injection molding. Pre- and postshift respiratory status measures and azodicarbonamide concentrations were also obtained for 17 employees. Cross-sectional pulmonary function differences by injection molding status were not observed. Modest decrements in pulmonary function measures were observed between start and end of shift but with no dose-effect relationship. A strong association was observed for injection molding workers for eye/nose/throat irritation, cough, and wheezing. Additionally, wheezing, chest tightness, and symptoms of chronic bronchitis were strongly associated with work in injection molding during periods in which azodicarbonamide was in use. These results suggest respiratory symptom causation by some combination of azodicarbonamide itself, reaction products of azodicarbonamide formed during injection molding, or other unidentified agents uniquely associated with the process of injection molding with azodicarbonamide foaming agent.     

流动注射分析法测定醋酸泼尼松片含量均匀度的研究

根据蓝四氮唑与泼尼松生成蓝色产物,并于525nm 波长处测定吸光度。测定条件为:反应管长度为3.8m(0.5mm id);流速为1.6ml/min;反应温度为55±0.5℃;注射样品溶液为100μl;本测定系统的测定速度可达100次/h;线性范围可达0.09mg/ml;检测限量为1.54μg/ml;测定结果的变异系数小于1%。     

曲肘式机构的优化设计

以功效系数为目标函数,相应地确定了设计变量和约束函数,对塑料注塑机合模机构的参数进行优化计算,提高了机构的综合性能。