Cutaneous afferent activity in the median nerve during grasping in the primate

Neural activity was recorded from the median nerve of a monkey during grasping and lifting, using a chronically implanted cuff electrode. At the onset of lifting, there was an initial dynamic response during which the intensity of the neural signal increased rapidly. This neural response attained its peak value well before the displacement, the load force or the grip force. The time course and peak of the rectified, integrated neurogram were best correlated with the rate of change of grip force. The neural activity declined exponentially to a steady value following the initial peak. During steady holding the mean amplitude of the neurogram was best correlated with the mean grip force. At the end of the holding phase there was a short burst of neural activity as the monkey relaxed the grip force and released the object. During some blocks of trials pulse perturbations were applied to the object. When the monkey did not increase the grip force in advance of the perturbation, the perturbation produced a relatively large displacement of the object and a burst of neural activity whose onset coincided with the onset of displacement. When the monkey anticipated the perturbation by increasing the grip force during the holding period preceding the perturbation, the perturbation produced a relatively small displacement and relatively little increase in neural activity.     

使用新型倒刺电极的骶神经调节治疗神经源性膀胱的初步临床结果

目的探讨应用新型倒刺电极（Tined-lead）对神经源性膀胱患者行S骶神经调节（SNM）的初步疗效。方法对5例神经源性膀胱患者采用新型倒刺电极，在X线监测下将电极植入S3骶神经孔，进行SNM。术前、术后详细记录排尿日记，用影像尿动力学方法评估患者的膀胱尿道功能。结果患者1（隐性骶裂）术后排尿次数和排尿量分别改善22％和49％；患者2（隐性骶裂）术后排尿次数、排尿量和残余尿量分别改善0．7％、11％和46％；患者3（隐性骶裂）术后排尿次数、排尿量和残余尿量分别改善0．4％、18％和44％。患者4（脑外伤）术后漏尿次数和漏尿量分别改善36％和54％。患者5（高位截瘫）术后间歇导尿次数和导尿量分别改善42％和54％，尿动力学参数改善37％～45％。结论用新型倒刺电极进行SNM为神经源性膀胱的治疗提供了一条新的可供选择的微创方法。     

氨气敏电极法快速测定血氨

本文介绍使用氨气敏电极,采用标准曲线法简便、快速、准确测定血氨的方法。取空腹血1ml,用1M HClO_4沉淀蛋白,以0.1M NH_4Cl—0.6MNa_2SO_4作内充液,碱化后的上清液可在2～3min内测试完毕。40例正常成人血氨的测定结果:■=31.4μmol/L N;S=6.4μmol/L N;■±2S(正常值范围)为18.6～44.2μmol/L N。10份血样的平均回收率为100.4％。该法用血少、简便、快速;结果较稳定、准确,适用于临床检验。     

The growth of the second underpotentially deposited silver layer on Pt(100)

The electrodeposition of Ag on Pt(100)-(1 × 1) in perchlorate electrolyte was studied by means of time-resolved in situ scanning tunnelling microscopy (STM) and cyclic voltammetry. One monolayer of Ag is deposited underpotentially (upd) ca. 500 mV positive of the Ag⁺/Ag equilibrium potential. Several millivolts positive of the equilibrium potential, a second well defined upd layer forms. Its growth was observed to proceed via island formation and coalescence. This process occurs in two separate stages that manifest themselves in voltammetric peaks as well as in the STM images.     

用混合粘合剂碳糊电极测定丁螺环酮

用混合粘合剂碳糊电极测定丁螺环酮张正奇，曾鸽鸣，刘传桂，黎艳飞（湖南大学化学化工系，长沙４１００８２）碳糊电极无毒，制作方便，表面更新容易，应用电位范围广，在药物分析中已有应用［１～５］。我们在液体石腊中加入添加剂，组成混合粘合剂，可显著改善电极的检...     

植物神经癫痫52例脑电图分析

报道52倒6个类型植物神经癫痫,重点分析了脑电图的变化,脑电图异常率100％,69.4％的病例出现两侧阵发性4～7Hzθ节律及6和14Hz阳性棘波,提示中线深部有功能紊乱,亦支持丘脑及脑干部有病变。此外蝶骨电极能提高脑电图对本病的阳性诊断率,值得采用。本文证明脑电图对植物神经性癫痫与非癫痫的鉴别诊断,具有肯定的价值。     

铲状电极经尿道前列腺电汽化切割术120例报告

目的：探讨铲状电极经尿道前列腺电汽化切割术中的手术经验及疗效。方法：总结了120例经尿道前列腺电汽化切割手术的治疗资料。结果：术后随访1月～2年，120倒手术患者118例治愈，2例于术后出现急性肾衰，经保守对症治疗痊愈，2例出现压力性尿失禁，经对症治疗好转。结论：铲状电极行前列腺组织的汽化切割，优于滚轮汽化电极或电极弧，术中术后出血少，术中术野清晰，安全可靠。     

Thickness effects of a carbon-supported platinum catalyst layer on the electrochemical reduction of oxygen in sulfuric acid solution

The influence of the thickness of a carbon-supported platinum catalyst layer on the oxygen reduction reaction (orr) has been studied in sulfuric acid solution by means of a thin-film rotating disk electrode. Pronounced changes in the Pt utilization, electrode activity and the orr kinetics have been observed upon varying the catalyst layer thickness. The thicker film electrode exhibits a higher Pt utilization efficiency and higher activity, and promotes the orr kinetics at potentials relevant to fuel cell operations. The participation of Pt surfaces not in contact with the electrolyte solution in electrochemical reactions via the spillover of adsorbed hydrogen and oxygen species, is proposed to be responsible for the changes. The thicker catalyst layer is likely to modify the Pt particle–particle distance by providing shared Pt sites between adjacent carbon supports, to improve the surface density of active catalyst particles per single carbon support by sharing adjacent catalyst sites, and to increase the ratio of the particle surfaces free of blocking anions to the catalyst|electrolyte interface surfaces. The carbon-supported platinum catalyst layer becomes active at 0.90 V vs RHE only when the catalyst layer is thicker than 1 μm. To provide reasonable activity, the minimum catalyst layer thickness should be around 2–4 μm. These results should be considered in the design of the cathode catalyst layer of polymer electrolyte membrane fuel cells.     

ABL50血气分析仪电、液路故障维修

本文介绍ABL50型血气分析仪使用过程中遇到的电、液路故障处理方法。     

Nucleus24型人工耳蜗植入后的电极有效性

目的：随访耳蜗植入后出现蜗外电极或坏损电极的情况，评价人工耳蜗植入后电极的有效性。方法：1998年6月至2002年8月53例Nucleus CI24M型耳蜗植入者，在术中及术后映射调图时进行电极阻抗测试，确定有无电极坏损及其坏损时间。开机时拍摄耳蜗位X线平片，确定电极是否完全植入。分析手术过程和术者经验对电极有效性的影响。结果：电极出现坏损的比例为13．2％，电极在术中插拔两次以上而造成电极坏损的危险度为0．4656。4年累积生存率达96．2％。不完全植入的比例为15．1％，其中又以耳蜗形态异常者居多(7／11)。结论：Nucleus CI24M型植入体在开机1～4年内的可靠性较高。电极序列在术中插拔两次以上，是导致电极坏损的主要原因。患者耳蜗的纤维化、畸形以及术者经验等因素可能导致电极不完全插入。