心电、呼吸信号采集分析系统的研制

设计一种用于移动监护系统的生理信息采集及预处理装置。该装置以ARM为核心,包括低功耗的双路心电信号放大、滤波、抗基线漂移电路。实现了心电信号的采集、预处理、简单分析及从心电信号中提取呼吸信号等功能。     

早期心电异常检测系统的研制——心电积分图

心电积分图是对心电信号进行一系列积分转换，是分析心电信号早期变化的一种无创性方法，能把ＥＣＧ的相对面积和间变化放大，用于冠状动脉疾病引起的心电信号早期的检测。     

基于小波变换的心电信号去噪综合算法

目的：研究去除心电信号中的基线漂移、工频干扰和肌电干扰等噪声,提高心电信号的自动识别和诊断精度。方法：利用Coif4小波对心电信号进行8尺度分解,采用小波分解重构法去除基线漂移,然后利用改进的小波闽值算法去除工频干扰和肌电干扰。结果：利用Matlab仿真工具,选择MIT-BIH心率失常数据库中信号进行验证,能有效去除这三种噪声,并且很好的保持R波的信息。结论：本算法在不丢失心电信号有用信息的前提下,可以较好的去除三种常见的噪声,可以用于心电信号自动分析之前的预处理。     

心电信号的采集及R波同步检测

心电信号的R波识别在室速和房颤的同步除颤中具有十分重要的意义。传统的软件识别往往不能达到实时效果,而硬件识别则可以有效解决这一难题。本研究主要包括应用硬件电路构成的心电信号的采集系统和R波同步检测。硬件部分设计采用胸部双电极单导联输入心电信号,放大后再经微分电路和全波整流电路的处理,最后通过可选择的电压窗口比较器输出最终的R波信号检测结果。     

基于小波变换的心电信号去噪算法

目的:去除在心电信号采集过程中混入的肌电干扰、工频干扰、基线漂移等噪声信号,避免噪声对心电信号特征点的识别和提取造成误判和漏判。方法:首先利用coif4小波对心电信号按Mallat算法进行分解,然后采用软、硬阈值折衷与小波重构的算法进行去噪。结果:采用MIT/BIH Arrhythmia Database中的心电信号进行仿真、验证,有效去除了三种常见的噪声信号。结论:本方法实时性好,为临床分析与诊断奠定了基础。     

高频心电图检测与分析方法的研究

前言 用普通热笔式心电图机记录下的常规心电图,其最高频率分量为100Hz左右,心电信号小许多幅度小、时程短的高频成份因被衰减而不能记录下。采用频率响应宽的高灵敏度的检测系统即可检测显示100Hz以上的高频成份(100Hz～2KHz)。我们把含有100Hz以上频率成份的心电信号称为高频心电图(High Frequency Electrocardiogram,     

基于MIT-BIH心律失常数据库的医用生理信号系统的设计

目的:设计一个心电信号研究系统,该系统是远程心电监护仪器研制中的重要组成部分.方法:先用高性能的PC机和高性能的DA转换器搭建一个硬件平台,再以Visual C++6.0为平台,利用面向对象语言编程建立MIT-BIH心电数据库.结果:系统可以对MIT-Bill心电数据库中的心电和呼吸数据进行管理和回放,并建立实验数据平台,来产生模拟的心电、呼吸等生理信号,可用于研发远程心电监护仪器调试使用.结论:可为以后心电信号的研究分析和相关仪器的开发提供了一个优秀的研究平台.     

基于Visual C++的MIT-BIH心电数据管理系统的设计

目的:识读MIT-BIH心电数据库格式,为研究心电监护系统提供信号源,为心电算法的仿真打好了基础.方法:以VC++6.0为平台,利用面向对象语言编程读取心电数据,经过D/A转换输出到心电监护系统,仿真验证心电算法.结果:心电信号输出与回放同步,可有效控制信号源.实现截取、保存、回放任一段心电波形.结论:系统平台可作为心电信号软件管理平台,提供给心电监护系统进行仿真试验.     

基于SOPC技术的多路并行ECG实时检测分析系统的设计

针对目前心电监护设备微型化、实时性、高采样率、存储量大等实际需求,采用了一种基于最新的SOPC（System On a Programmable Chip）技术的心电检测系统的设计。将DSP和MCU的功能集成在一块FPGA上,在FPGA内部实现多路心电信号的并行处理,由SD卡记录较长时间的连续心电信号,并实现心电信号的实时分析和心律失常的预警等扩展功能。     

基于心电信号的飞行员应激评价模型的研究

本文基于教练机飞行员训练期间的心电信号,以人体瞬间应激水平为评价依据,通过采集特殊的飞行作业期间的飞行员的心电信号,计算心率以及心率变异性的相关指标,对个体产生瞬间应激的心电信号进行心率相关指标分析以及心率变异性的时域指标分析.同时对应激反应下心率曲线面积变化进行分析,采用多尺度算法,构建了应激强度随训练次数变化的函数关系,揭示了飞行训练应激强度变化的规律,提出了飞行训练及应激阶段的划分方法,建立了基于心电信号的飞行员应激评价的模型.     

神经干细胞体外增殖分化的钙成像研究

神经干细胞具有广阔的应用前景,但对于其增殖和分化的内源机制、外部环境信号还并不十分了解。研究表明,钙信号很可能在其中起到了调控作用。利用钙离子成像技术,观察神经干细胞的单细胞体外增殖和分化过程,记录了在细胞分裂过程中钙信号变化的曲线。发现细胞增殖和分化过程中都会产生钙浓度的变化,但在细胞分裂后期两者钙信号的模式却存在差别。实验结果提示,胞内钙水平的波动只是细胞增殖的伴随产物,但却是细胞分化的必要条件。由此提出钙信号对神经干细胞分化调控机制的假设,并指出其对今后研究的意义。     

A new MSPQC system for rapid detection of pathogens in clinical samples

A new multi-channel series piezoelectric quartz crystal (MSPQC) system for detection of pathogens in clinical sample was proposed. Some factors, which affect the detection of pathogens by using MSPQC, were all investigated. A total of 650 clinical samples were detected by MSPQC and compared with licensed BACTEC 9120 system (Becton Dickinson Diagnostic Instrument Systems, Sparks, MD, USA) simultaneously in the Third Xiangya Hospital of Central South University, China. When the incubation period was 5 days, two systems had similar detected results: the MSPQC system detected 123 growth of 650 (18.92%) bottles while the BACTEC 9120 detected 125 growth of 650 (19.23%) bottles. The MSPQC had 2 false-positive signals and 2 false-negative signals. However, BACTEC 9120 had 3 false-positive signals and 0 false-negative signals. Further identifications of bacteria were run by VITEK-2 (bioMérieux China Ltd.), 5% sheep blood trypticase soy agar (SBA) and chocolate agar (CA). Comparing with BACTEC 9120, MSPQC system possesses following advantages: shorter average detection time, less blood volume needed, less false-positive results and low cost. It can also provide information in real time. So MSPQC has a wonderful perspective in clinical application.     

Effect of hyperhomocysteinemia on the protein kinase DYRK1A in liver of mice

Hyperhomocysteinemia due to cystathionine beta synthase (CBS)-deficiency confers diverse clinical manifestations, notably liver diseases. Even if hyperhomocysteinemia in liver of CBS-deficient mice, a murine model of hyperhomocysteinemia, promotes mitochondrial oxidative stress and pro-apoptotic signals, protective signals may counteract these pro-apoptotic signals, leading to chronic inflammation. As DYRK1A, a serine/threonine kinase, has been described as a candidate antiapoptotic factor, we have analyzed the expression of DYRK1A in liver of CBS-deficient mice. We found that DYRK1A protein level was reduced in liver of CBS-deficient mice, which was not observed at the gene expression level. Moreover, the use of primary hepatocytes/Kupffer cells co-culture showed that degradation of DYRK1A induced by hyperhomocysteinemia requires calpain activation. Our results demonstrate a deleterious effect of hyperhomocysteinemia on DYRK1A protein expression, and emphasize the role of hyperhomocysteinemia on calpain activation.     

Signalling Asymmetry in the Communication of the Water Strider Aquarius remigis in the Context of Dominance and Spacing in the Non-mating Season

The role of high-frequency ripple signals (HF signals) made by males of the water strider Aquarius remigis was studied in the contexts of competition for food and general spacing behaviour during the non-mating season. HF signals were played back through the ripple-producing legs of males during dyadic agonisdc encounters, using a signal-driven wire coil to oscillate a magnet glued to a leg. These signals were in addition to normal signals. The additional signals significantly increased the number of retreats by non-magneted males, showing that the signals increased the dominance of a non-territorial male. Hence, our results increase the number of contexts in which HF signals of A. remigis function. Males, but not females, avoided a site occupied by a magneted dead male through which HF signals were played. Thus, the communication system used by A. remigis males during competition for food seemed to be ignored by females, suggesting sex-specific signals even in a non-mating context. Evolutionary models of signalling often assume that contestants have evolved the same repertoire of signals in order to resolve conflicts peacefully. This water strider system thus poses an interesting challenge for future theoretical and empirical research on communication asymmetry.     

MR并行采集技术的临床应用

在MR技术被临床应用的数十年其间,不断出现的新技术使信号采集速度和图象质量得到了很大的提高,其中之一的并行采集技术对信号采集速度的提高起了十分重要的作用。介绍了MR并行采集技术研究现状及临床应用情况,并对其存在的问题和发展前景进行了探讨。     

The linear electrode array: a useful tool with many applications.

In this review we describe the basic principles of operation of linear electrode arrays for the detection of surface EMG signals, together with their most relevant current applications. A linear array of electrodes is a system which detects surface EMG signals in a number of points located along a line. A spatial filter is usually placed in each point for signal detection, so that the recording of EMG signals with linear arrays corresponds to the sampling in one spatial direction of a spatially filtered version of the potential distribution over the skin. Linear arrays provide indications on motor unit (MU) anatomical properties, such as the locations of the innervation zones and tendons, and the fiber length. Such systems allow the investigation of the properties of the volume conductor and its effect on surface detected signals. Moreover, linear arrays allow to estimate muscle fiber conduction velocity with a very low standard deviation of estimation (of the order of 0.1-0.2 m/s), thus providing reliable indications on muscle fiber membrane properties and their changes in time (for example with fatigue or during treatment). Conduction velocity can be estimated from a signal epoch (global estimate) or at the single MU level. In the latter case, MU action potentials are identified from the interference EMG signals and conduction velocity is estimated for each detected potential. In this way it is possible, in certain conditions, to investigate single MU control and conduction properties with a completely non-invasive approach. Linear arrays provide valuable information on the neuromuscular system properties and appear to be promising tools for applied studies and clinical research.     

Molecular pathogenesis of pancreatic cancer: advances and challenges

Pancreatic ductal adenocarcinoma (PDAC) is still a devastating and incurable disease with a median survival of 3-6 months and a 5-year survival rate of 1-4% when all stages are considered. Although crucial advances in our understanding of the molecular pathogenesis of the disease have been made, the exceptional aggressiveness of PDAC remains largely unexplained. Some key results will probably direct future PDAC research activities. For example, recent identification of pancreatic tumor stem cells has stimulated the debate over the cell of origin. Further, powerful new genetically engineered mouse models support the concept that stepwise progression of epithelial precursor lesions leads to invasive PDAC as a result of accumulating mutations in K-ras, INK4A/ARF, TP53 and DPC4; these models accentuate the initiating function of the K-ras mutation. Established PDAC exhibits all the classic hallmarks of cancer, including self-sufficiency in growth signals, insensitivity to anti-growth signals, evasion of apoptosis, limitless replicative potential, sustained angiogenesis, tissue invasion, and metastasis. This review provides an overview of the molecular machinery that PDAC utilizes to acquire these tumorigenic capacities. Moreover, recent advances have identified essential elements of key pathways partly recapitulating developmental signals, and of the tumor microenvironment that promotes tumor growth through the complex interplay of its different cellular components. In spite of progress in molecular research, there is still a dichotomy between the encouraging results obtained with targeted interference of numerous oncogenic pathways in vitro and a lack of significant improvement in clinical detection and survival. Thus our primary challenge remains to translate the solid knowledge of genetic and epigenetic alterations in PDAC into clinical tools which can be used for early diagnosis and effective therapy.     

Axon guidance: Robos make the rules

A central feature of the developing nervous system is the midline region, which guides growing axons with both short- and long-range signals. New research shows that a trio of receptors, the Robos, are crucial in allowing axons to interpret these signals, ensuring correct route-finding within the emerging axon scaffold.     

Metastasis-inducing S100A4 protein: implication in non-malignant human pathologies

The role of S100A4 in tumor progression and metastasis is well documented in numerous research articles and summarized in several reviews. Currently S100A4 is categorized as an essential metastasis-promoting factor whose production and secretion from "activated" stromal cells (fibroblasts, immunocytes and vascular cells) is initiated and stimulated by signals derived in tumor cells (cytokines, growth factors and others). However recent data gained from experimental and clinical studies significantly extend our knowledge on S100A4. Implications of S100A4 in various non-malignant pathological conditions have been demonstrated by number of research groups. In the mini-review we attempted to highlight the role of S100A4 in other than cancer important human pathologies, such as autoimmune inflammation (RA) and disorders in cardio-vascular, nervous and pulmonary systems. We suggest that diverse human diseases might have common molecular components and pathway(s). Possibly, inflammatory machinery and S100A4 as its intrinsic constituent could contribute to the pathogenesis of various disorders. Therefore, we presume that facts on S100A4 performance could be attractive for broad range of researchers and clinicians.     

检测A组轮状病毒的微阵列技术初探

采用荧光染料TAMRA标记上游引物,经RT semi nestedPCR扩增A组轮状病毒的保守区域,并将扩增产物与自行研制的玻片微阵列进行杂交。经杂交信号扫描分析,可简便快速地检出A组轮状病毒,并能达到高灵敏性,为下步进入临床打下了基础。