成年大鼠肠系膜血管中CGRP免疫反应神经纤维的密度分布

用免疫组织化学ＡＢＣ法结合葡萄糖氧化酶ＤＡＢ－硫酸镍铵显色及交点计数法测量纤维密度的定量技术，研究了ＣＧＲＰ免疫反应神经纤维（ＣＧＲＰ－ＩＲＦ）在成年大鼠肠系膜上动脉和静脉中的密度分布规律。结果发现，成年大鼠肠系膜上动脉（ＳＭＡ）和静脉（ＳＭＶ）及其各级分支血管上含有较密集的呈网络状走行的ＣＧＲＰ－ＩＲＦ。ＳＭＡ中ＣＧＲＰ－ＩＲＦ的密度不随分支级别的增加而变化；而ＳＭＶ中ＣＧＲＰ－ＩＲＦ的密度随分支级别的增加呈指数曲线减少。此两种伴行血管之间ＣＧＲＰ－ＩＲＦ的密度在较细的血管分支中基本一致，而在较粗的血管分支中ＳＭＶ中ＣＧＲＰ－ＩＲＦ的密度大于ＳＭＡ中。     

干扰素调节因子-7对肿瘤细胞生长的影响

干扰素 (ＩＦＮ)调节因子 (ＩＦＮｒｅｇｕｌａｔｏｒｙｆａｃｔｏｒ ,ＩＲＦ)是一组通过与ＩＦＮ基因中顺式元件结合来调节ＩＦＮ及其诱导性基因表达的核因子。到目前为止 ,已发现至少有 9种ＩＲＦ ,以ＩＲＦ 1和ＩＲＦ 2的研究最多。基本明确ＩＲＦ 1是免疫上调因子 ,促进ＩＦＮ γ表达 ;ＩＲＦ 2是免疫负反馈调节因子 ,抑制ＩＲＦ 1的过度表达。近年发现 ,ＩＲＦ 1直接抑制肿瘤生长 ,上调ＭＨＣⅠ和ＭＨＣⅡ的表达。ＩＲＦ 3也是肿瘤细胞生长的强抑制因子 ,诱发肿瘤细胞凋亡。ＩＲＦ 7是 1998年发现的另一ＩＲＦ因子 ,与ＩＲＦ 3在氨基酸…     

在呼吸气流描记测量中利用自适应FIR滤波器对呼吸伪差的在线消除

在呼吸气流描记测量中利用自适应ＦＩＲ滤波器对呼吸伪差的在线消除［英］／ＹｅＪ…／／ＭｅｄＢｉｏｌＥｎｇＣｏｍｐｕｔ．—１９９４，３２．—６２０阻抗呼吸气流描记是一种简单的非创伤描记技术，该技术可以反映人体肺循环系统中血管的状况。但是，大量的、并且几乎...     

肝硬化患者联合检测AFP，β_2－MG，CA－50的结果分析

肝硬化患者联合检测ＡＦＰ，β_２－ＭＧ，ＣＡ－５０的结果分析韦振元，王洁ＡＦＰ、β２－ＭＧＲＩＡ、ＣＡ－５０ＩＲＭＡ目前已在肿瘤诊断中广泛应用，本文对５０例肝硬化病人的检测结果作一分析。５０例均为来自我院门诊及住院经其它检查确诊的肝硬化患者。ＡＦＰ、?..     

应用双脱氧指纹法检测苯丙氨酸羟化酶基因突变

目的提高苯丙氨酸羟化酶基因突变的检出效率，快速对苯丙酮尿症患儿进行产前诊断。方法采用双脱氧指纹（ｄｉｄｅｏｘｙｆｉｎｇｅｒｐｒｉｎｔｉｎｇ，ｄｄＦ）检测技术，ｄｄＦ法是将单链构象多态（ｓｉｎｇｌｅｓｔｒａｎｄｃｏｎ－ｆｏｒｍａｔｉｏｎｐｏｌｙｍｏｒｐｈｉｓｍ，ＳＳＣＰ）分析技术和双脱氧测序技术结合为一体的检测基因突变的方法，它能有效地检测基因突变而不受扩增片段长度的限制。用ｄｄＦ法鉴定了苯丙氨酸羟化酶基因上的突变Ｙ１６５Ｘ，Ｙ２０４Ｃ和Ｑ３５５Ｈ。结果有多条泳带不同于正常对照泳带。采用ＳＳＣＰ技术，也检测出突变Ｙ１６５Ｘ和Ｑ３５５Ｈ显示了不同于正常的泳带位移，而扩增片段较长的含突变Ｙ２０４Ｃ的样本却未显示异常泳带。结论ｄｄＦ检测技术对大片段基因的突变检测比ＳＳＣＰ法更为敏感，是检测基因突变切实可行的方法     

比较两种去基线漂移的滤波算法

心电图中的低频干扰是影响心电图识别的一个重要因素。本文将介绍两种快速滤波器（小滤波器和ＦＩＲ滤波器），并从速度和滤波性能两方面对其进行比较。证明两种方法在Ｔ波正常的情况下，均可以光滑地跟踪基线漂移。在Ｔ波极端高大的情况下，小波滤波器受到的影响较小     

心室晚电位检测中消除振铃方法的研究

ＦＧＩＲ作者着重研究了心室晚电位（简称ＶＬＰ）检测中，进行带通滤波时，振铃现象对晚电位检测的影响及消除。我们采用双向滤波、最小相移滤波及ＦＩＲ滤波等方法探讨了振铃对ＶＬＰ的影响，比较了各种方法对振铃的抑制作用。为了考察各种方法对ＶＬＰ检出能力，作者采用了在相干平均后的心电波形上桑加与真实情况一致的仿真ＶＬＰ形的方法，比较了上述方法对ＶＬＰ的检出作用，并在证实了传统双向滤波对振铃作用的基础上，从理论     

心电信号处理中滤波器设计的研究

由体表电极(胸导联或肢导联)检测到的ECG心电信号常有不同的干扰,为了得到不失真的原始心电信号,在诊断分析前要进行必要的预处理--滤波.本文详细介绍了在处理动态心电图系统记录的ECG信号中各种滤波器的设计,包括去除各种噪声的低通、高通、带阻滤波器以及一次性滤波器.     

急性白血病患儿脑脊液PCR扩增HCMV－DNA的研究

应用多聚酶链式反应（ＰＣＲ）扩增和洋地黄探针杂交的方法，对５３例急性白血病（ＡＬ）患儿脑脊液（ＣＳＦ）样本进行了检测。经过ＰＣＲ扩增，可见明显的人巨细胞病毒ＤＮＡ（ＨＣＭＶ－ＤＮＡ）４００ｂｐ扩增带；经洋地黄探针特异性杂交鉴定，ＡＬ患儿ＣＳＦ标本ＰＣＲ扩增产物的ＨＣＭＶ－ＤＮＡ阳性检出率为８３．０２％。本实验为ＡＬ病人ＣＳＦ的ＨＣＭＶ检测提供了一个简便方法。     

急性白血病患儿脑脊液PCR扩增HCMV—DNA的研究

应用多聚酶链式反应（ＰＣＲ）扩增和洋地黄深针杂交的方法，对５３例急性白血病（ＡＬ）患儿脑脊液（ＣＳＦ）样本进行了检测，经过ＰＣＲ扩增，可见明显的人巨细胞病毒ＤＮＡ（ＨＣＭＶ－ＤＮＡ）４００ｂｐ扩增带，经洋地黄探针特异性杂交鉴定，ＡＬ患儿ＣＳＦ标本ＰＣＲ扩增产生的ＨＣＭＶ－ＤＮＡ阳性检出率为８３．０２％。本实验为ＡＬ病人ＣＳＦ的ＨＣＭＶ检测提供了一个简便方法。     

R wave detection using fractional digital differentiation

In this paper, a fractional digital differentiation-based algorithm for detecting R wave in QRS complex of electrocardiogram (ECG) is developed. A FIR bandpass filter, whose coefficients only depend on fractional orders, reduces various noises present in ECG signals and generates peaks corresponding to the ECG parts with high slopes. This filter is followed by nonlinear transforms and smoothing to enhance peaks corresponding to R waves. Algorithm tests on the Massachusetts Institute of Technology/Beth Israel Hospital (MIT/BIH) ECG database illustrate the capability of this novel approach to recognizing QRS complexes in very noisy ECG signals. The algorithm’s performances are comparable to those of the most efficient QRS detectors tested on this database.     

New algorithm for the detection of the ECG fiducial point in the averaging technique

The use of the coherent averaging technique applied to the electrocardiographic signal implies the location of a fiducial point as a synchronisation reference. An algorithm easily adaptable to a personal computer, operable in real time, insensitive to mains and to ECG-baseline fluctuations, with a low jitter value and the capacity to trigger any ECG signal wave or complex, has been developed. The algorithm detects those waveforms which, within certain confidence intervals, are morphologically equal to a reference wave. This wave is chosen by the user as the repetitive waveform within which the fiducial point is to be located. A two-window template and differential parameters are used. The possibility of building the template permits the user to adapt the algorithm to each patient's ECG. To evaluate its accuracy objectively, a software simulation was built of a generator capable of producing test signals as the sum of the 'useful' signal plus 'noise'. A jitter standard deviation of 1.65 ms was obtained in the worst test (SNR = 10 dB; noiseband = 0-50 Hz), which shows the excellent recognition accuracy of the algorithm.     

一种基于自适应的新滤波技术

在心电信号的采集过程中,不可避免地会混入肌电噪声和各种干扰信号,为节获得含有较小噪声的ＥＣＧ信号,便于分析,需要对采集到的ＥＣＧ信号作消噪处理。     

自适应算法与小波变换在心电信号滤波中的应用

心电信号是一种基本的人体生理信号,具有重要的临床诊断价值。然而,体表检测人体心电信号中常带有工频干扰、基线漂移、肌电干扰等各种噪声,给临床对心血管疾病的诊断带来了障碍。为了消除心电信号检测过程中带有的上述三种噪声,采用LM S自适应算法及小波变换理论,有针对性的设计了自适应滤波器、小波变换滤波器和自适应信号分离器等三种数字滤波器来滤除相应干扰。结果表明,对心电信号中存在的这三种噪声具有很好的滤波效果。     

基于小波神经网络的心电信号滤波研究

针对心电(ECG)信号检测中存在的主要噪声,本文研究了基于小波神经网络(WNN)的ECG信号滤波理论。提出一种通过WNN非线性逼近能力构建的针对ECG信号的非线性滤波器算法和滤波策略,实现对ECG信号中基线漂移、肌电干扰、工频干扰噪声的滤除;给出了网络训练算法和滤波实验,滤波后信号与期望信号误差范围在微伏级,验证了本文提出的基于WNN的心电非线性滤波器对心电主要噪声快速滤波的良好效果,最后讨论了影响WNN用于心电滤波的几个关键问题。     

Noise and baseline wandering suppression of ECG signals by morphological filter

Electrocardiogram (ECG) signals describe the electrical activity of the heart, and are universally by physicists in the diagnosis of cardiac pathologies. However, during the acquisition of ECGs they are often contaminated with different sources of noise, making interpretation difficult. Different techniques have been used to filter the ECG signal, in order to optimize the signal to noise ratio (S/N). In this paper, an approach based on morphological filtering is developed in order to filter the ECG. Morphological filtering is concerned with the detection of the ECG morphology, therefore allowing the suppression of noises and particularly baseline wandering. The implemented filter is evaluated using signals taken from the MIT-BIH ECG universal database. The results show that the performance of this filter is good compared with other filtering techniques.     

基于FPGA的两种高速高阶FIR滤波器的设计与比较

目的 设计满足全数字眼科超声系统高速高性能信号处理需要的数字滤波器.方法 用加入流水线级的并行乘累加方式和基于分割表的并行分布式算法设计基于现场可编程门阵列(FPGA)的32阶高速FIR低通滤波器,并在Quartus Ⅱ开发平台及Modelsim仿真平台上进行仿真验证.结果 2种方式设计的FIR滤波器经仿真验证,均满足设计要求.结论 通过对设计结果的分析比较,基于分割表的并行分布式算法设计的滤波器能在灵活配置资源占用的情况下,实现高速数据处理,为全数字眼科超声系统中滤波器的实现方法提供了选择的依据.     

基于FPGA的数字滤波器在超声诊断设备中的应用进展

在超声诊断系统中,一个重要的环节就是实时处理庞大的超声信号,尤其是用数字硬件电路实时进行信号处理.信号处理的关键部分就是滤波器的设计,数字滤波器的设计会直接影响超声诊断设备的性能.简要介绍数字滤波器的分类,着重介绍近年来基于现场可编程门阵列（FPGA）的多种数字滤波器的硬件实现方法,尤其是经典数字滤波器中基于分布式算法实现有限脉冲响应（FIR）滤波器;分析了每种数字滤波器的优点及存在的问题;展望了超声诊断设备中现代数字滤波器的发展趋势.     

Optimal digital filters for long-latency components of the event-related brain potential

A fundamentally important problem for cognitive psychophysiologists is selection of the appropriate off-line digital filter to extract signal from noise in the event-related brain potential (ERP) recorded at the scalp. Investigators in the field typically use a type of finite impulse response (FIR) filter known as moving average or boxcar filter to achieve this end. However, this type of filter can produce significant amplitude diminution and distortion of the shape of the ERP waveform. Thus, there is a need to identify more appropriate filters. In this paper, we compare the performance of another type of FIR filter that, unlike the boxcar filler, is designed with an optimizing algorithm that reduces signal distortion and maximizes signal extraction (referred to here as an optimal FIR filter). We applied several different filters of both types to ERP data containing the P300 component. This comparison revealed that boxcar filters reduced the contribution of high-frequency noise to the ERP but in so doing produced a substantial attenuation of P300 amplitude and, in some cases, substantial distortions of the shape of the waveform, resulting in significant errors in latency estimation. In contrast, the optimal FIR filters preserved P300 amplitude, morphology, and latency and also eliminated high-frequency noise more effectively than did the boxcar filters. The implications of these results for data acquisition and analysis are discussed.