Quantitative Gait Evaluation of Hemiplegic Patients Using Electrical Stimulation Orthoses

Although the functional electrical stimulation orthosis is one of the most recent approaches to the rehabilitation of hemiplegic patients, the quantitative estimate of its influence on the patients walking is not satisfactorily solved. In this communication the variables necessary for gait evaluation are defined and two quantitative methods for their interpretation are given. The second method was tested on eight hemiplegic patients. The results show the applicability of the described techniques of evaluation.     

Solvent-Activated Current Passing Tape Electrode for Transcutaneous Electrical Stimulation of the Peripheral Nervous System

Development of a solvent-activated current passing tape electrode system has improved significantly the clinical efficacy of transcutaneous electrical nerve stimulation. Developmental work with this electrode system in combination with solid-state battery-operated pulse generators has opened new and interesting areas of application, including pain relief, muscle stimulation, and use as an indifferent electrode.     

Electrical Properties of nMOSFETs Using the NiSi:Yb FUSI Electrode

In this letter, nMOSFETs using a NiSi:Yb fully silicide (FUSI) electrode are demonstrated for the first time. We report that the integration of NiSi:Yb FUSI into our reference n-FETs with the respective SiON / HfSiON gate dielectrics results in a V_t reduction from 0.55/0.52 down to 0.30/0.43 V, without degradation of the gate dielectric integrity, channel interface states, and long channel device mobility     

Photolithographic Fabrication and Physiological Performance of Microelectrode Arrays for Neural Stimulation

The development of an auditory cochlear prosthesis which works by direct electrical stimulation of the auditory nerve creates the need for a multielectrode stimulation array which is small in size, rugged, resistant to electrolysis, and stable and reproducible in its electrical and mechanical properties. This paper describes the fabrication of such microelectrode arrays using planar lithographic techniques.     

Electrical Stimulation with Pt Electrodes: AMethod for Determination of "Real" Electrode Areas

An electrical method is describqd which is suitable for determining exposed areas of Pt-stimulation electrodes prior to implantation.     

A Computer-Controlled Multichannel Stimulation System for Laboratory Use in Functional Neuromuscular Stimulation

Laboratory instrumentation systems for developing functional neuromuscular stimulation (FNS) orthoses must be flexible in command processing and in multichannel stimulus control and coordination. For research and development of new FNS systems to control the musculoskeletal function of disabled individuals, we have developed a computer-controlled multichannel stimulation system. This system both processes patient generated input commands delivered from a variety of sources, and coordinates the multichannel stimulation to achieve the desired movement. The flexibility provided by this system has proven to be of great value in both upper and lower extremity FNS.     

离焦激光直写光刻工艺研究

采用理论计算和光线追迹分析了激光直写光刻中离焦对写入焦斑光场分布的影响;使用四轴激光直写设备开展了离焦激光直写光刻工艺实验,实验和理论计算及光线追迹的结果吻合得很好。利用离焦激光直写光刻方法制作了光栅和分划版,测得实验结果达到工艺要求。     

Time-Interleaved Analog-to-Digital-Converter Compensation Using Multichannel Filters

Published methods that employ a filter bank for compensating the timing and bandwidth mismatches of an $M$ -channel time-interleaved analog-to-digital converter (TIADC) were developed based on the fact that each sub-ADC channel is a downsampled version of the analog input. The output of each sub-ADC is filtered in such a way that, when all the filter outputs are summed, the aliasing components are minimized. If each channel of the filter bank has $N$ coefficients, the optimization of the coefficients requires computing the inverse of an $MN times MN$ matrix if the weighted least squares (WLS) technique is used as the optimization tool. In this paper, we present a multichannel filtering approach for TIADC mismatch compensation. We apply the generalized sampling theorem to directly estimate the ideal output of each sub-ADC using the outputs of all the sub-ADCs. If the WLS technique is used as the optimization tool, the dimension of the matrix to be inversed is $N times N$. For the same number of coefficients (and also the same spurious component performance given sufficient arithmetic precision), our technique is computationally less complex and more robust than the filter-bank approach. If mixed integer linear programming is used as the optimization tool to produce filters with coefficient values that are integer powers of two, our technique produces a saving in computing resources by a factor of approximately $(10^{0.2N(M - 1)})/(M-1)$ in the TIADC filter design.      

EEG Measurement During Electrical Stimulation

When the EEG is recorded during electrical stimulation, large artifacts will appear in the EEG signal as a result of the stimulation pulses. The circuit presented suppresses these artifacts before the signal enters the amplifier. This way, saturation of the amplifier and filtering of the artifacts, which otherwise would disturb the EEG measurement, are prevented.     

有线数字电视中多通道字幕的实现

有线电视数字化改造后,在TS流上插入字幕的方式也与原来的模拟系统完全不同了,传统的模拟字幕机已无法实现在多个频道中同时叠加字幕。详细介绍了目前有线数字电视中多通道插入字幕的实现过程,为市、县级网络公司、电视台数字电视广告增值业务提供了很好的借鉴。     

An Integrated System for Simultaneous, Multichannel Neuronal Stimulation and Recording

Precision electronics that provide multi-electrode stimulation and recording capabilities are an important tool for the experimental study of neuronal development and plasticity. Towards this end, we present a custom analog integrated circuit (IC), fabricated in a 0.35-mum process, incorporating stimulation buffers and recording preamplifiers for multiple electrodes onto a single die. The architecture of the IC allows for arbitrary, independent configuration of electrodes for stimulation or recording, and the IC includes artifact-elimination circuitry that returns the stimulation electrode to its previous voltage following stimulation, minimizing the interference with recording. We analyze the thermal noise levels in the recording preamplifiers and experimentally measure input-referred noise as low as 4.77 muV_rms in the frequency range of 30 Hz-3 kHz at a power consumption of 100 muW from a total power supply of 3.8 V. We also consider the temporal response and stability of the artifact elimination circuitry. We demonstrate that the use of the artifact-elimination circuitry with a 30-mum diameter stimulation electrode permits a return to recording mode in les 2 ms after stimulation, facilitating near-simultaneous stimulation and recording of neuronal signals. (Patent applied for, U.S. No. 2007/0178579.)     

A Multichannel Depth Probe Fabricated Using Electron-Beam Lithography

A multielectrode probe structure is described in which several thin-film metal electrodes are defined on the outer surface of a glass micropipette using electron-beam lithography. Electrode geometries are controlled to within one micron, resulting in electrode recording characteristics which are extremely well matched. Recording sites are 5 , um wide rings spaced 100 , um apart in depth. Analysis and characterization show the structure to be capable of accurately recording tissue potentials with a minimum of tissue damage. Use of these probes in current source-density (CSD) analysis of extraceliular current flow is described.     

Multichannel Blind Source Separation Using Convolution Kernel Compensation

This paper studies a novel decomposition technique, suitable for blind separation of linear mixtures of signals comprising finite-length symbols. The observed symbols are first modeled as channel responses in a multiple-input-multiple-output (MIMO) model, while the channel inputs are conceptually considered sparse positive pulse trains carrying the information about the symbol arising times. Our decomposition approach compensates channel responses and aims at reconstructing the input pulse trains directly. The algorithm is derived first for the overdetermined noiseless MIMO case. A generalized scheme is then provided for the underdetermined mixtures in noisy environments. Although blind, the proposed technique approaches Bayesian optimal linear minimum mean square error estimator and is, hence, significantly noise resistant. The results of simulation tests prove it can be applied to considerably underdetermined convolutive mixtures and even to the mixtures of moderately correlated input pulse trains, with their cross-correlation up to 10% of its maximum possible value.     

利用幅度谱或多信道信息求解半盲反褶积

本文指出对于一维有限时宽实序列,输入x(n),系统单位样值响应y(n),几乎总能由x(n)(或y(n))的幅度谱和输出z(n)唯一确定。本文进一步指出利用多信道输出信息z_1(n),x(n)及y_1(n)几乎总能唯一被确定,其中i表示第i个信道。文中给出了四个利用已知信息重构有限长能量有限序列x(n),y(n)的唯一性定理。     

595nm脉冲染料激光非损伤嫩肤的动物实验研究

评估脉冲染料激光非损伤嫩肤后皮肤的组织学变化及真皮胶原蛋白含量的变化,初步探讨脉冲染料激光非损伤 嫩肤的机理,为有效的临床治疗提供借鉴。实验采用590nm的脉冲染料激光。24只昆明小鼠随机分为4组,1组对照组,3组 实验组。三种能量的激光各照射5次,间隔3天,光斑有10％的重叠。照射后进行常规的病理学切片,HE和VG染色,目镜 测微尺测量真皮胶原纤维的厚度,SPSS进行数据分析。激光照射后短期内可以观察到轻微的炎症反应,长期观察发现小鼠皮 肤表皮和真皮厚度明显增加,真皮胶原纤维排列整齐有序,成纤维细胞数量增加,没有观察到水疱和红斑等副反应。8 J／cm2、 10 J／cm2和12 J／cm2组真皮胶原纤维的厚度分别比对照组高29％(p<0.05)、35％(p<0.05)和38％(p<0.05),但它们之间 没有统计学上的显著差异。证明595nm的脉冲染料激光非损伤嫩肤是一种安全有效的的嫩肤方法。     

Multichannel Filters Using Chirped Bandgap Structures in Microstrip Technology

We demonstrate two techniques for creating several narrowband transmission channels within the ultra-wide stopband of a chirped electromagnetic bandgap structure in microstrip technology. In contrast to previous demonstrations which inserted defects into single-frequency-tuned bandgap structures using ground-plane etching, we demonstrate the use of local pi phase-shifts (defects) and "Moire"-type superposition in a sinusoidal chirped bandgap structure having a network topology. We demonstrate the design of 4-to-6-channel filters with lower insertion losses (<5 dB) and broader stopbands than previous approaches in microstrip.     

光学活体成像技术进展

光学活体成像技术是近年来生物医学检测中发展最快的前沿科学之一,能够在微创或无创的条件下对活体组织或动物体内的生理生物活动进行成像跟踪,其中某些技术可以达到动态实时监测.总结了目前常用和最新的光学活体成像技术,并对其在生物医学领域的应用做了介绍与展望.     

In Vivo Modeling for Glucose Homeostasis

A model for the glucose-insulin control system has been developed. The primary controllers in this model are the pancreas and liver. These subsystems operate within the metabolic environment to maintain normal glucose levels. The prime control variables for each subsystem, as well as for systemic glucose utilization, are the plasma glucose and insulin concentrations perfusing these organs.     

An Implantable Current Source for Electrical Nerve Stimulation

A CMOS bipolar voltage controlled current source is described which due to its low part count lends itself very well to integration in a thin film hybrid circuit. The standby power consumption is less than 400 ?W.     

Multidimensional Multichannel FIR Deconvolution Using GrÖbner Bases

We present a new method for general multidimensional multichannel deconvolution with finite impulse response (FIR) convolution and deconvolution filters using GrÖbner bases. Previous work formulates the problem of multichannel FIR deconvolution as the construction of a left inverse of the convolution matrix, which is solved by numerical linear algebra. However, this approach requires the prior information of the support of deconvolution filters. Using algebraic geometry and GrÖbner bases, we find necessary and sufficient conditions for the existence of exact deconvolution FIR filters and propose simple algorithms to find these deconvolution filters. The main contribution of our work is to extend the previous GrÖbner basis results on multidimensional multichannel deconvolution for polynomial or causal filters to general FIR filters. The proposed algorithms obtain a set of FIR deconvolution filters with a small number of nonzero coefficients (a desirable feature in the impulsive noise environment) and do not require the prior information of the support. Moreover, we provide a complete characterization of all exact deconvolution FIR filters, from which good FIR deconvolution filters under the additive white noise environment are found. Simulation results show that our approaches achieve good results under different noise settings.