Isolation of Protoplast and Ion Channel Recording in Plasma Membrane of Suspension Cells of Populus euphratica

The authors used suspension cells of Populus euphratica to isolate protoplast in the present study. Protoplasts were successfully obtained after 4 hours incubation in enzyme solution containing 1 0% cellulase “onozuka” R\|10, 0\^01% pectolyase Y\|23,0\^15% macerozyme R\|10 and 0\^1% hemicellulase at 25℃. Outward and inward single channels in plasma membrane were observed using cell\|attached recording of patch\|clamp technique. In this study, single channel records showed that more than one species of channel were obtained. These attempts in protoplast isolation and ion channel recording offers the opportunity to characterize cellular mechanisms of salt tolerance in tree species.

The on-line direct fitting of low signal-noise ratio single ion channel recordings based on hidden Markov models

Many kinds of channel currents are especially weak and the background noise dominates in the patch clamp recordings. This makes the threshold detection fail during estimating of the transition probabilities. So direct fitting of the patch clamp recording, not of the histogram coming from the recordings, is a desirable way to estimate the transition probabilities. Iterative batch EM algorithm based on hidden markov model has been used in this field but which has the "curse of dimensionality" and besides cant keep tracking the varying of the parameters. A new on line sequential iterative one is proposed here, which needs fewer computational efforts and can adaptively keep tracking the varying of parameters. Simulations suggest its robust, effective and convenient.

Applicability of initial optimal maternal and fetal electrocardiogram combination vectors to subsequent recordings

A series of experiments are conducted to confirm whether the vectors calculated for an early section of a continuous non-invasive fetal electrocardiogram （fECG） recording can be directly applied to subsequent sections in order to reduce the computation required for real-time monitoring. Our results suggest that it is generally feasible to apply the initial optimal maternal and fetal ECG combination vectors to extract the fECG and maternal ECG in subsequent recorded sections.

Evolution and distribution of macroscopic gas channels in an overburden strata

The evolution of gas bearing channels in the roof,and their spatial distribution,was studied.A complete consideration of gas flow changes through the stress-strain changes in the roof near a working face is made.The theoretical abutment pressure distribution using displacement monitors and borehole visual recording instruments allow a theoretical analysis.Field test research determined the conditions for formation of macroscopic gas channels.These appear along the working face roof,normally distributed to it.These results show that the coal rock stratification becomes a macroscopic gas channel boundary if its deformation is less than the lower layer,or greater than the layer above it.At the same time the stability is greater than the distance from the roof for hanging dew conditions.The working face advances and the roof gas channels experience a cycle of development.Microscopic channels dominate the initial stage then macroscopic gas channels form,develop,and close.The evolution of the macroscopic channels depends on the ratio between the distances from the new compaction area in the goaf to the initial stress area in front of the working face.The amount of daily advance of the face also affects channel development.The experimental observations in one mining area showed that the main gas channels are located about 2 and 6.2 m above the lower surface of the roof and that they have an evolution period 7 to 11 days long.

Acetylcholine modulates transient outward potassium channel in acutely isolated cerebral cortical neurons of rats

BACKGROUND： The neuronal transient outward potassium channel has been shown to be highly associated with acetylcholine. However, the influence of acetylcholine on the transient outward potassium current in cerebral cortical neurons remains poorly understood. OBJECTIVE： To investigate acetylcholine modulation on transient outward potassium current in rat parietal cortical neurons using the whole-cell patch-clamp technique. DESIGN, TIME AND SETTING： A neuroelectrophysiology study was performed at the Department of Physiology, Harbin Medical University between January 2005 and January 2006. MATERIALS： Wistar rats were provided by the Animal Research Center, the Second Hospital of Harbin Medical University; PC-IIC patch-clamp amplifier and IBBClamp data collection analysis system were provided by Huazhong University for Science and Technology, Wuhan, China; PP-83 microelectrode puller was purchased from Narrishage, Japan. METHODS： The parietal somatosensory cortical neurons were acutely dissociated, and the modulation of acetylcholine （0.1, 1, 10, 100 μmol/L） on transient outward potassium channel was recorded using the whole-cell patch-clamp technique. MAIN OUTCOME MEASURES： Influence of acetylcholine on transient outward potassium current, potassium channel activation, and inactivation. RESULTS： The inhibitory effect of acetylcholine on transient outward potassium current was dose- and voltage-dependent （P 〈 0.01）. Acetylcholine was found to significantly affect the activation process of transient outward potassium current, i.e., the activation curve of transient outward potassium current was left-shifted, while the inactivation curve was shifted to hyperpolarization. Acetylcholine significantly prolonged the time constant of recovery from inactivation of transient outward potassium current （P 〈 0.01）. CONCLUSION： These results suggest that acetylcholine inhibits transient outward potassium current by regulating activation and inactivation processes of the transient outward potassium channel.

Effects of tetrodotoxin monoclonal antibody on the blocking action of tetrodotoxin on sodium channels

The effect of tetrodotoxin(TTX) monoclonal antibody (McAb) 8A5 on the blocking action of TTX on sodium channels was studied by using the electrophysiological technique of whole cell recording.We found the specific TTX McAb have the following characterizations: TTX sensitivity to NG108-15 cell was high , with sodium ion current of NG108-15 cell completely blocked by only 10-6 mol/L level of TTX; when the cell was treated with TTX McAb 8A5 for 1 min and 5min, after the sodium current was completely abolished by TTX, the sodium ion current was restored to 79. 44%?. 20% and 73. 89%?. 74% (n=5) of the control values respectively; when the cell was treated for 1 min with 8A5 and TTX which had been mixed for 1 h before added,the sodium ion current was maintained at 89. 21%?. 41% (n=4) of the control. These results indicated that TTX-induced blockage on the sodium ion current could be powerfully antagonized by TTX McAb 8A5 with two distinct administering ways.

Effects of antigliomatin from the scorpion venom of Buthus martensii Karsch on chloride channels on C6 glioma cells

Using whole-cell patch-clamp recordings, the effects of antigliomatin were observed on chloride channels on C6 glioma cells cultured in vitro. Antigliomatin was extracted from the venom of the scorpion Buthus martensii Karsch. Chloride channels are closed under normal osmotic pressure. When osmotic pressure was reduced to 120, 110 and 100 mV, the cell volume enlarged, chloride channels opened, and the chloride channel current increased. Three minutes after antigliomatin treatment, the chloride channel current decreased in a dose-dependent manner. These results show that antigliomatin extracted from the venom of the scorpion Buthus martensii Karsch diminishes chloride channel currents on C6 glioma cells.

基于正则表达式和Jaccard系数的智能变电站录波通道同源匹配

针对220kV及以上电压等级智能变电站双套录波通道同源匹配问题,提出一种基于正则表达式和Jaccard系数的智能变电站录波通道同源匹配方法。首先,针对录波通道命名不规范的问题,使用正则表达式对通道名称文本进行预处理,统一通道名称的表达形式;同时,使用jieba分词算法和去停用词操作,去除通道名称文本中可能存在的冗余信息。然后,使用Jaccard相似系数匹配算法计算录波通道名称文本之间的相似度,依据相似度大小筛选出同源通道。最后,基于电网实际的录波文件数据进行仿真分析。仿真结果表明:所提方法可有效实现智能变电站录波通道同源匹配。

基于最小二乘法的变电站故障录波测距系统设计

当前,变电站故障区域受录波器性能的影响,阻抗值获取难度较大,导致故障区域测距效率较低。为提高变电站故障区域的测距效率、确保变电站的供电稳定,设计了基于最小二乘法的变电站故障录波测距系统。在系统硬件部分,采用分布式的电力故障录波器装置,收集变电站电力数据,利用以太网后台机完成数据传输。在系统软件部分,凭借最小二乘法计算模拟量通道的变比参数,校正电力录波装置通道间的相位误差,以提高录波器模拟量的测量精度。通过故障相电流差与相电压差获得阻抗值结果,计算出变电站故障录波的准确距离。试验结果表明:所设计系统的步角误差与测距误差均较小,故障录波测距误差降到了1%以内。该系统可以有效完成变电站故障点的精准定位,具有较高的参考价值。

音频混音技术在多声道录音中的应用

探讨音频混音技术在多声道录音中的应用,以提高音频制作的质量与效果。概述音频混音技术的基本概念和原理,具体分析声道同步、空间定位、频谱均衡、动态处理以及环境效果融合等关键技术在多声道混音中的应用,以期提升混音质量与效果。

在体多通道电生理记录技术在大鼠痛情绪研究中的应用

目的:通过已建立的完全弗氏佐剂(CFA)诱导的条件位置逃避(CPA)行为模型,利用在体多通道电生理学记录技术,结合行为观察研究大鼠发生CPA反应时前扣带皮层(ACC)脑区神经元的电活动。方法:电极制作,电极埋置,在体多通道技术记录清醒大鼠r ACC脑区神经元的电活动及其CPA行为记录。结果:1自制的多通道阵列电极可成功记录到ACC神经元的放电活动;2大鼠脚掌注射CFA前后分别与不同环境匹配后,大鼠处于"痛环境"与"非痛环境"时ACC神经元spike的发放频率分别为痛环境(0.85±1.38)imp/s,非痛环境(0.22±0.97)imp/s(P<0.05,n=26);3行为学分析痛环境适应前(303.55±61.77)s对比痛环境适应后(140.32±33.52)s(P<0.05,n=6)。上述结果显示,脚掌注射CFA的大鼠处于痛环境时诱发ACC神经元spike放电频率增强与行为上的逃避反应同步发生;脚掌注射生理盐水的对照组并无上述反应趋势。结论:大鼠r ACC脑区神经元电活动与疼痛所致的痛厌恶相关情绪的发生有着密切的联系。

肟硫磷中毒肌无力大鼠骨骼肌烟碱样乙酰胆碱受体通道特性

目的 探讨肟硫磷引起肌无力大鼠骨骼肌烟碱样乙酰胆碱受体 (nAChR)通道特性的改变 ,揭示其发生机制。方法 用ip 1 .1 5g·kg-1肟硫磷制作成年大鼠肌无力模型 ,同时ip 1 6mg·kg-1阿托品以对抗毒蕈碱样症状。染毒后 0 .5～ 2h,8只大鼠出现肌无力 ,7只大鼠肌力正常。将 3只肌无力大鼠于肌力恢复后 (染毒后 1 2～ 1 8h) ,其余大鼠于染毒2～ 3h后 ,断颈处死 ,取后肢趾短屈肌 ,酶解制备骨骼肌纤维 ,用膜片钳对肌纤维nAChR通道做单通道电流记录。结果 肌无力大鼠nAChR单通道开放频率、表观平均开放时间、平均开放时间和电导均显著低于对照组和肌力正常的染毒大鼠 ,且肌力恢复后 ,以上各参数均接近对照组。结论 肟硫磷中毒引起肌无力可能与肟硫磷导致或促进nAChR的脱敏 ,以及阻断nAChR通道的开放有关。

分布式继电保护与稳定控制系统通道录波装置

针对基于光纤通道的继电保护与稳定控制系统,开发了分布式通道录波装置,弥补了现有通 信网管系统只能监测通道连接状态不能记录通道通信内容的缺陷。装置采用电气全隔离高阻跨接 方式,跨接在保护装置与脉码调制(PCM)设备之间的通信电缆上,实时监测和分析通道状态及保 护控制装置之间的通信内容,并按指定的过滤条件记录通信报文,从而为事故分析提供准确依据。

大鼠背根神经节分离细胞离子单通道记录技术

本文探讨了在大鼠背根神经节(DRG)细胞上记录离子单通道电流的方法,研究了膜片钳实验的各个环节,研究了提高封接电阻的方法。研究结果表明,单通道记录的背景噪声取决于电极与细胞的封接水平。文中还讨论了实验系统的组装,电极制备和细胞分离等技术。

一种基于TCP时间戳选项的时间隐蔽信道方法

为提高计算机网络的可靠性和抗检测性,提出了一种新型时间式隐蔽信道和一种新型的包间间隔描述方法,该描述方法称为记录式包间间隔。通过采用传输控制协议(TCP)时间戳选项构造记录式包间间隔,进而构造隐蔽信道,采用TCP的可靠交付服务和重传机制,提高信道在恶劣网络环境下的传输正确率,小幅改变时间戳并采用熵抚平方法,提高信道的抗检测性。在TCP/IP网络下实现了新型时间式隐蔽信道,并通过实验对比其与传统时间式隐蔽信道的可靠性和抗检测性。实验证明,提出的信道在恶劣网络环境下的传输正确率优于传统信道,且足以抵抗熵检测。

危重患者护理记录在绿色通道患者质量控制中的应用

目的 应用危重患者护理记录对急诊绿色通道救治缺陷进行分析,以期加强急诊质量控制.方法 收集天津市第五中心医院急诊科2011年6月1日至2015年5月31日绿色通道收治的严重创伤患者抢救记录共206份,其中2011年6月1日至2013年6月30日的抢救记录单104份为对照组,2013年7月1日至2015年5月31日危重患者护理记录102份为研究组.分析采用两种记录单后质量控制可利用率、不良事件发生率和患者满意率.结果 研究组临床质量控制可利用率明显高于对照组[80.0％（32/40）比57.5％（23/40）,P＜0.05],研究组不良事件发生率明显低于对照组[3.9％ （4/102）比8.7％ （9/104）,P＜0.05],患者满意率明显高于对照组[93.1％ （95/102）比83.7％ （87/104）,P＜0.05].结论 采用危重患者护理记录便于强化医护人员规范、熟练执行抢救流程,有利于临床质量控制的进一步完善.

记忆过程中海马CA1区神经元的集群放电特征

观察空间工作记忆过程中海马CA1区神经元群的放电特征。应用多通道神经元集群放电记录技术,同步观察和记录清醒大鼠在执行延迟选择任务时的行为轨迹以及海马CA1区神经元的放电活动。发现:海马CA1区位置细胞的位置野是在学习过程中逐渐形成并可消退;部分位置细胞的放电对未来目标定向性行为具有预测作用;在空间工作记忆过程中,神经元放电之间的相关性加强,神经元之间以及神经元与局部场电位之间存在相位编码方式。结果提示海马CA1区神经元参与对空间信息的初级编码和加工,并为未来行为决策提供有效信息,而且海马对信息的加工是通过局部神经网络进行,时间编码可能是海马信息加工的重要方式之一。

单通道和全细胞记录技术

离子通道的活动是可兴奋细胞传递信息的基础 ,膜片钳技术的发明导致了生命科学的一场革命。对膜片钳的工作模式、记录模式。

通道录波装置在电网安全稳定控制系统的应用

介绍通道录波技术和装置,并以南方电网罗平站为例介绍通道录波装置在现场实际运行厂站的应用。通道录波技术和装置在电网安稳系统的应用提供了一种可靠有效的方法监测通道,以及可信的证据来分析和评价设备状态。

离子通道电流虚拟仿真实验在生理教学中的应用

利用模拟离子通道电流仿真实验教学设备替代高成本的膜片钳-离子通道测量平台,以降低实验成本,满足更多学生进行科研实验的需要。通过虚拟仿真实验,能够观察到离子通道蛋白分子的电流记录曲线,通过分析处理得到电压-电流分析曲线和通道关闭时间统计曲线,从而帮助学生理解离子通道蛋白的开-关特性和电压依赖特性,同时培养学生在离子通道蛋白的电生理特性科研方面的实际操作能力。