磁探测电阻抗成像及其在经络三维定位中的应用

目的:经络是中医理论基础的核心组成,而经络理论研究的关键是三维定位,成像是经络三维定位的一种科学且实用的方法。方法:通过讨论经络实质和经络定位的研究方法和现状,以及生物电阻抗成像(electrical impedance tomogra-phy,EIT)的各种方法,对比分析了应用于经络定位时各类方法的优缺点。结果:比较EIT的各种方法可得磁探测电阻抗成像(magnetic detection electrical impedance tomography,MD-EIT)具有明显的优势,适用于经络三维定位。结论:MD-EIT不仅应用于经络定位,还可应用于心肺检测和肿瘤诊断等,它在医学方面有广泛的应用,具有极大的发展空间。     

采用图像匹配和三维跟踪器的人体经络可视化方法**

背景：经络信息可视化技术采用图形图像与视觉的表现形式,将现实中不可见的人体经络显示于计算机屏幕上,使抽象的经络信息展现在人们面前,用以辅助经络定位和临床诊治。 目的：为更方便有效地提供人体经络可视化方法,基于磁场跟踪器和摄像机标定技术,开发一种基于电阻抗的人体经络检测和可视化系统。 方法：将多通道经络检测中各个通道的电阻抗与由磁场跟踪器所确定的相应通道电极探针触点的三维坐标进行配对,利用经络低电阻抗特性和代价函数从候选通道中选择准确的经络点并确定三维经络线;然后用“张正友”法和图形变换法进行优化,将经络线的三维坐标映射到人体皮肤表面的二维图像上;随着电极探头移动,整条经络线就可显示在皮肤表面的二维图像上。 结果与结论：研究和实验结果表明,系统的阻抗检测误差小于0.2%,并可实时地在现场人体体表图像上准确有效地显示人体经络。该方法实现了人体经络的可视化,可用于医生临床诊断治疗或中医教学。      

用于无创心功能检测的心阻抗微分信号处理

基于胸部生物阻抗技术开展对心脏血流动力学参数准确计算的前提是心阻抗微分信号特征点的准确识别。为提高心阻抗微分信号特征点识别的准确率,本文首先设计了自适应集合经验模态和小波阈值降噪技术相结合的信号预处理方法,然后根据自适应集合经验模态分解的结果,结合差分法和自适应分段技术定位了心阻抗微分信号中的A、B、C和X点。本研究以临床上采集到的30例病理性心阻抗微分信号为例,对本文所提算法的特征检测准确度进行检验。研究结果显示,本文所提算法对信号特征的准确识别率总体可达99.72%,进一步保证了基于胸部生物阻抗技术的心脏血流动力学参数的计算准确度。     

中医脉诊柔性阵列式压力传感器设计

目的 采集脉搏过程中的取脉点动态压力分布,用于对中医诊脉指端感受描述的客观化研究.方法 设计制作了柔性封装的中医脉诊压力传感器阵列,用于取脉点动态压力分布的采集.阵列单元采用硅压阻式压力传感器,以1.95 mm间距的等边三角形分布在直径为15mm的圆形基板上,共计37个.使用柔性树脂包覆阵列单元以模拟人体指端表皮包覆触觉小体的结构.各个阵列单元的压力信号经过差分放大后被采集和送往上位机处理,获得取脉点动态压力分布.结果 以阵列式压力传感器为核心搭建了取脉点动态压力分布采集系统,通过中医脉诊采集实验,证明该系统能够采集并绘制出取脉点动态压力分布.结论 阵列式压力传感器能够用于取脉点动态压力分布的采集,反映了中医脉诊时的指端触觉感受,为中医脉诊客观化研究提供了一种更为准确的依据.     

基于电阻抗技术的多通道呼吸监测系统

目的为及时检测到早期呼吸系统疾病引起的呼吸功能的改变,本研究开发了一套采用生物电阻抗技术同时监测胸部和腹部的呼吸电阻抗信号的多通道呼吸监测系统。方法本系统主要分为3个单元：电阻抗数据采集单元、多通道开关单元和控制单元。电阻抗数据采集单元完成生物电阻抗数据高精度的检测,多通道开关单元完成不同部位数据采集通道之间的转换,控制单元采用LabVIEW编程实现对电阻抗数据采集单元和多通道开关单元的控制、同步采集、数据的显示及存储。利用本系统采集5名健康人长跑5000m前后胸部和腹部的同步呼吸电阻抗信号,采用一种新的参数定量描述胸部和腹部的呼吸电阻抗信号的同步程度。结果长跑前后胸部和腹部同步呼吸电阻抗信号的同步程度具有显著差异（P〈0．01）。结论基于电阻抗技术的多通道呼吸监测系统能够有效用于多个部位呼吸电阻抗信号的同步监测,为早期呼吸系统疾病的检测提供辅助诊断信息。     

基于小波变换的心阻抗微分信号去噪及特征点检测研究

利用心阻抗微分信号的特征点可计算出多个血流动力学参数,进而判别心功能状态,因此特征点的准确提取显得尤为重要。本文应用实验室自行设计开发的KF_ICG型无创心功能检测仪采集了健康人和重庆市大坪医院22例患者数据,应用小波阈值法对采集的数据进行降噪处理,对降噪后的信号采用bior3.7小波进行6层分解后定位特征点。结果表明,该法无论对健康人还是存在诸多噪声干扰的临床患者数据都能有效实现特征点的精确定位,有助于实现阻抗法无创检测血流动力学参数的临床应用。     

一种新型胃动力检测系统的设计与实现

目的 以生物阻抗技术为基础设计胃动力检测系统.方法 检测系统由采集平台和分析平台2部分构成.前者实现胃电和胃动力阻抗信号的同步采集和数据传输,后者对提取的胃动力阻抗信号和胃电运用小波多分辨分析进行处理,并提取信号的时域、频域和支配频率等参数完成统计分析.结果 实验结果表明功能性消化不良患者（病理组）的胃运动正常节律百分比（PNF）和正常功率百分比（PNP）明显小于健康大学生志愿者（对照组）,病理组的节律变异系数（FIC）和功率变异系数（PIC）大于对照组.结论 胃动力检测系统的实现不仅使胃电和胃阻抗信息得到同步获取,同时为胃动力研究和临床检测提供一种电-机复合过程的检测方法.     

一种新型胃动力检测系统的设计与实现

目的 以生物阻抗技术为基础设计胃动力检测系统.方法 检测系统由采集平台和分析平台2部分构成.前者实现胃电和胃动力阻抗信号的同步采集和数据传输,后者对提取的胃动力阻抗信号和胃电运用小波多分辨分析进行处理,并提取信号的时域、频域和支配频率等参数完成统计分析.结果 实验结果表明功能性消化不良患者(病理组)的胃运动正常节律百分比(PNF)和正常功率百分比(PNP)明显小于健康大学生志愿者(对照组),病理组的节律变异系数(FIC)和功率变异系数(PIC)大于对照组.结论 胃动力检测系统的实现不仅使胃电和胃阻抗信息得到同步获取,同时为胃动力研究和临床检测提供一种电-机复合过程的检测方法.     

基于因子分析的生物电阻抗技术的睡眠呼吸容积监测

目的 为了消除睡眠姿势变化对呼吸容积监测的影响,提出一种基于双通道生物电阻抗技术对左右肺呼吸阻抗信号进行数据融合实现呼吸容积监测的新方法。方法 本文搭建了一套基于双通道生物电阻抗技术的睡眠呼吸容积监测系统,用多导生理信号记录仪MP150(BIOPAC,美国)采集10名受试者依次保持仰卧、左侧卧和右侧卧3种睡眠姿势下平静呼吸时的呼吸流速信号以及左右肺和胸腔的呼吸阻抗信号。以呼吸流速信号为金标准,比较通过因子分析法得到的左右肺融合信号和单通道胸腔的呼吸阻抗信号。结果 相比于单通道阻抗方法,因子分析方法获得的左右肺融合的呼吸阻抗信号与金标准信号之间的平均误差值要更小,且一致性更好。结论 基于双通道阻抗技术结合因子分析的数据融合算法是一种可信的睡眠呼吸容积监测新方法。     

一种基于胸阻抗法的心功能无创检测分析仪

目的为了经济、快捷、全面地实现心功能的无创检测,基于胸阻抗法成功研发了一种心功能无创检测分析仪,可方便地实现胸阻抗信号、心电信号、心音信号的同步检测分析,从而实现对患者心功能的无创综合评价。该方法无毒无创,操作简单,完全可以实现家用化普及。方法本文首先描述了系统的硬件模块构成,说明了胸阻抗信号的采集过程。其次,使用FPGA芯片与DDS芯片构成系统的控制与信号发生核心,指出了恒流源的精度等性能指标。再次,指出了胸阻抗信号处理的要点,运用互感原理实现干扰信号的隔离。最后,介绍了仪器软件功能,并展示了仪器软件实测结果。结果通过临床试验,对胸阻抗法与超声多普勒法检测的数据结果进行t检验,结果表明二者具有一致性。结论由于采用了先进的特征点判别方法,该设备具有较高的临床检测精度和较好的临床适用性,可满足临床心功能无创检测和评估的要求。     

Germinal center B cell initiation,GC maturation,and the coevolution of its stromal cell niches

Throughout the developing GC response, B cell survival and fate choices made at the single cell level are dependent on signals received largely through interactions with other cells, often with cognate T cells. The type of signals that a given B cell can encounter is dictated by its location within tissue microarchitecture. The focus of this review is on the initiation and evolution of the GC response at the earliest time points. Here, we review the key factors influencing the progression of GC B cell differentiation that are both stage and context dependent. Finally, we describe the coevolution of niches within and surrounding the GC that influence the outcome of the GC response.     

基于摄动思想的中医处方模糊聚类分析

基于信息技术的中医方剂自动分析,对中医经验的挖掘和传承具有重要意义.本文采用基于摄动思想的模糊聚类方法,对中医方剂进行了聚类分析研究.其中首先对方剂各味药的性味归经毒性进行模糊化处理,然后将基于传递闭包的摄动思想应用到方剂药群的聚类分析.然后以小柴胡汤的聚类分析为例,将此方法与传统的传递闭包矩阵聚类方法进行了比较.实验结果表明,与传统的传递闭包矩阵的模糊聚类方法相比,基于摄动思想模糊的聚类方法效果更好,可以更加客观地反映中医处方组方原则,对于方剂分析具有较好的指导意义.     

针刺“足三里”对经络线上微循环血流量的影响

为探讨针刺“足三里”对位于经络线上和经络线外的微循环血流的可能的不同影响，选择１９名受试者，使用激光多普勒流量计测量在针刺“足三里”前后，围绕该穴４个位点和２个位于远端经线上的位点的皮下微循环血流量。结果显示针刺“足三里”时沿经络线上的微循环血流量有显著的增高，而非经络线的位置血流量没有显著的改变。这说明经络的传导机制在针刺“足三里”时对血液微循环改善有十分重要的作用。     

一种基于阵列传感器设计和双曲定位模型的心尖搏动信号获取技术

目的针对传统单一传感器采集心尖搏动信号时因传感器位置不易确定，信号可靠性受质疑的问题，提出一种新的心尖搏动信号获取技术。方法采用阵列传感器设计，将3片完全相同的压电传感器设计成等边三角形结构，同步采集3路心尖搏动信号，同时对心尖搏动信号在胸腔传播过程中衰减的幅值特性和频率特性进行分析，建立心尖搏动信号的双曲定位模型，然后依据该模型重建出真实的心尖搏动信号。同步采集20例受试者的3路心尖搏动信号，以传感器A为基准信号，统计分析传感器B和C信号的3个特征点（C点、E点和0点）与基准信号的偏差有无显著性差异，进而说明单一传感器信号的可靠性。结果t检验结果显示传感器B和C信号的3个特征点与基准信号的偏差均有显著的统计学差异，提示心尖搏动信号易受传感器放置位置的影响，信号可靠性不高。结论本文提出的心尖搏动信号获取技术解决了单一传感器放置位置不易确定的缺陷，利用双曲定位模型重建出可靠性更高的信号波形。     

Target similarity affects saccade curvature away from irrelevant onsets

Saccade curvature away from visual distractors is a measure of the salience of these distractors for the oculomotor system. Three experiments are reported in which the integration of luminance onset signals and target similarity signals is examined, using a saccade curvature paradigm. Observers made saccades to a no-onset colour target in one of two positions on the vertical meridian. On most trials, an abrupt onset distractor that was either similar or dissimilar to the target appeared left or right on the horizontal midline. Saccades curved away from the irrelevant onsets; however, the amount of curvature was modulated by target similarity only when the onset appeared before the target (experiment 2) or when saccade initiation was delayed (experiment 3). These results suggest that the initial response to the onset is stimulus-driven and mediated by its transient component. Over time, the response is integrated with and augmented by top-down inputs. Visual and non-visual signals converge onto a common motor map to determine an item's salience.     

Optical imaging of breast tumor through temporal log-slope difference mappings

A novel optical temporal log-slope difference mapping approach is proposed for cancerous breast tumor detection. In this method, target tissues are illuminated by near-infrared (700-1000 nm) ultrashort laser pulses from various surface source points, and backscattered time-resolved light signals are collected at the same surface points. By analyzing the log-slopes of decaying signals over all points on the source-detection grid, a log-slope distribution on the surface is obtained. After administration of absorption contrast agents, the presence of cancerous tumors increases the decaying steepness of the transient signals. The mapping of log-slope difference between native tissue and absorption-enhanced cancerous tissue indicates the location and projection of tumors on the detection surface. In this paper, we examine this method in the detection of breast tumors in two model tissue phantoms through computer simulation. The first model has a spherical tumor of 6mm in diameter embedded at the tissue center. The second model is a large tissue phantom embedded with a non-centered spherical tumor 8mm in diameter. Monte Carlo methods were employed to simulate the light transport and signal measurement. It is shown that the tumor in both the tissue models will be accurately projected on the detection surface by the proposed log-slope difference mapping method. The image processing is very fast and does not require any inverse optimization in image reconstruction.     

Representation of eye position in primate inferior colliculus

We studied the representation of eye-position information in the primate inferior colliculus (IC). Monkeys fixated visual stimuli at one of eight or nine locations along the horizontal meridian between -24 and 24 degrees while sounds were presented from loudspeakers at locations within that same range. Approximately 40% of our sample of 153 neurons showed statistically significant sensitivity to eye position during either the presentation of an auditory stimulus or in the absence of sound (Bonferroni corrected P < 0.05). The representation for eye position was predominantly monotonic and favored contralateral eye positions. Eye-position sensitivity was more prevalent among neurons without sound-location sensitivity: about half of neurons that were insensitive to sound location were sensitive to eye position, whereas only about one-quarter of sound-location-sensitive neurons were also sensitive to eye position. Our findings suggest that sound location and eye position are encoded using independent but overlapping rate codes at the level of the IC. The use of a common format has computational advantages for integrating these two signals. The differential distribution of eye-position sensitivity and sound-location sensitivity suggests that this process has begun by the level of the IC but is not yet complete at this stage. We discuss how these signals might fit into Groh and Sparks' vector subtraction model for coordinate transformations.     

人体四肢经穴筋膜基础的医学影像学研究

目的:本研究尝试采用医学影像学方法,对人体四肢经穴的解剖结构加以观察,结合计算机三维重建技术,重点探索经络走行与筋膜分布密切相关的规律,为揭示经络的解剖学实质提供新的依据。方法:通过超声影像学观察、采用CT、MRI手段和把CT、MRI与三维重建技术相结合引进经络研究领域,为揭示经络与穴位的解剖学实质进行方法学上的创新性研究。结果:与传统中医记载的经络机理和走行线进行对比分析,发现有相似性。结论:中医经络的解剖学基础可能是分布于全身的筋膜结缔组织。     

人体双侧对称经络电阻抗失衡与疾病的相关研究

通过实验装置,分别测量人体双侧对称经络对称两穴位之间的电流波形,计算其电阻抗值,探讨经络的导电特性。证明了正常人双侧经络电阻抗的对称性、经络循行线的低阻性及双侧经络电阻抗失衡与其络属脏器病变的相关性等问题     

Distribution-based minimum-norm estimation with multiple trials

The goal of this study is to develop a source imaging method for electroencephalography and magnetoencephalography by analyzing a distance measure based on a Euclidean norm of difference between pre- and post-stimulus brain activities. Conventional source imaging techniques generally detect evoked responses by averaging multiple trials at each source point. These methods are limited in their ability to fully analyze complex brain signals with a mixture of evoked and induced activities because they compare means or variances. In this article, we propose a novel approach for eliciting significant evoked and induced activity. To this aim, response and baseline ranges from each trial are separately mapped in an anatomically constrained source space by minimum-norm estimation. The extent within a distribution and the distance between distributions of brain activities at each source point are estimated from the set of trials. Then, this distance analysis determines the degree of difference between the response and baseline activities. The statistical significance of the distance comparison was computed using a nonparametric permutation test. In the evaluation of simulated data sets, the proposed method provided robust images of the simulated location (p<0.05), whereas the average method did not detect the perturbed source. A total of 200 randomly selected locations were tested with a signal-to-noise ratio (SNR) of 2dB, and the error between simulated points and the maximum-value-points analyzed using this method was 9+/-15 mm.