生物雷达技术的研究现状

利用生物雷达技术检测人体生命体征信号(呼吸、心率等)成为生物医学工程研究中产生的一个崭新的领域，其主要任务是间隔一定的距离、穿透一定厚度的介质对人体的生命体征进行非接触检测，该技术可以广泛应用于军事医学、灾害医学、城市反恐等领域。     

生物雷达信号处理方法研究进展

生物雷达是雷达技术与生物医学工程技术相融合、可在较远距离探测生命信号的特殊雷达,是近年来国外提出的一种新概念雷达.该技术可用于生命体征探测以及非接触临床监护领域.生物医学信号处理方法是该技术得以实现的重要条件.生物雷达信号容易受到检测对象及环境的干扰,特别是呼吸运动回波信号较强,对心搏信号产生混合干扰,使其无法独立检出.因此大量信号处理方法运用在该技术的各个方面.介绍了生物雷达技术进展,以及当前主流信号处理方法的应用情况.     

基于生物雷达的人体步态非接触检测技术研究进展

人体步态是一个全身肌肉骨骼协调运行的复杂机制,具有特异性,可作为身份识别或临床疾病诊断的依据,在灾害救援、战场救护、反恐安保及医疗卫生等领域有着广泛的应用价值.传统的步态非接触检测技术主要包括光学图像和超声等,其易受光线、能见度及障碍物等因素影响.近年来,生物雷达技术发展迅猛,基于生物雷达的人体步态信号非接触检测技术更具优势,主要表现在:不受光线影响,可全天候识别;可穿透衣物、伪装甚至墙壁;可在烟、尘、雾等能见度低的天气条件下使用等.论述了生物雷达技术非接触检测人体步态的技术原理和方法,综述其研究现状,并对其发展趋势进行展望.     

一种人体生命体征检测的新方法

本文首先给出人体生命体征的基本定义及其呼吸、心跳的标准参考值,然后讨论目前最常见的接触式检测人体生命体征方法的原理、优缺点,最后重点讨论一种检测人体生命体征新方法－－非接触检测的原理、理论、优缺点及实验室研究现状,并给出实验室中在自由空间和穿透模拟砖墙条件下检测到人体呼吸、心跳两路信号的时域、频域检测结果。     

呼吸信号检测技术研究现状

呼吸检测方法主要分为接触式和非接触式2大类.接触式检测方法包括容积式呼吸检测法、速度式呼吸检测法、温度检测法、位移检测法、阻抗检测法、可穿戴技术和睡眠床垫等.这些方法属于无创检测且技术成熟,但都需要电极或传感器直接或间接接触人体,使人体受到一定的约束或限制,不适合用于严重烧伤患者和新生儿的呼吸监测.非接触式检测利用电磁波、光等媒介,使用无需与人体接触的电极或传感器,可在人体自然状态下对呼吸信号进行非接触检测,特别是基于红外线和生物雷达的非接触检测方法,已成为国内外研究的热点,可用于临床、社区医疗及家庭监护.     

心冲击图的雷达式非接触检测技术研究

本文介绍了一种检测人体心冲击图的全新技术。该技术运用多普勒雷达原理 ,采用低功率 (P <1mW)毫米波 (λ =8mm)为探测信号 ,探测距离S >10m。在检测对象着各类衣服 ,处于不同姿势、不同的天线照射角度等情况下 ,该技术均可较高质量的非接触、无约束检测到人体心冲击图。该研究为临床监护、家庭保健监护、灾害救护提供了诱人的前景。     

呼吸频率检测技术研究现状

在机体代谢中,呼吸是至关重要的。定期监测呼吸情况,能尽早发现并预防呼吸系统以及心脑血管等方面的病变。目前,呼吸检测技术主要分为接触式和非接触式两大类。这两种检测技术各有优缺点,其中接触式检测方法能简单并快捷地测量数据,而非接触式检测方法则是利用某些技术手段通过无创测量获取人体的数据。本文对呼吸检测技术的研究现状进行了阐述,并结合各个新技术的现有产品,分析了呼吸检测技术的适用范围及未来的研究方向。     

一种生物雷达呼吸和心跳信号实时分离技术

目的 本研究旨在从雷达式生命参数检测平台的回波信号中分离出呼吸和心跳信号,提取呼吸、心跳特征参数.方法 分析回波信号的特征,改进算法,将呼吸信号的谐波组合作为自适应滤波器的参考输入信号进行回波信号滤波处理实验.结果 提出了一种基于自适应谐波抵消的呼吸和心跳信号分离算法.结论 该算法在生物雷达模拟人体平躺实验中能够有效地分离出呼吸和心跳信号.     

基于雷达式非接触生命参数检测中跟踪干扰谱峰的二次滤波算法研究

为了抑制雷达式非接触生命探测系统中的动目标干扰，提出可跟踪干扰谱峰的滤波算法，用于检测受到同频带干扰影响的呼吸信号。对信号一次滤波后．进行Yule—Walker功率谱估计，发现可能的同频带干扰谱峰．通过与标准呼吸信号进行归一化互相关系数计算，对干扰谱峰定位，从而进行二次滤波，提取呼吸信号。结果表明，经二次滤波算法处理后，呼吸信号中同频带干扰谱峰被识别并抑制。对于单一同频带干扰谱峰，该算法能有效抑制同频带干扰，提取呼吸信号。     

Current state of pneumococcal vaccines

Streptococcus pneumoniae is a leading cause of bacterial pneumonia, meningitis, and acute otitis media in children and adults worldwide. According to World Health Organization estimates, at least 1 million children under 5 years of age die each year from pneumococcal pneumonia. The emergence of resistant strains necessitates the development of an effective vaccine with a large serotype coverage. The 11 most common serotypes cause 72-83% of all serious pneumococcal diseases worldwide. Currently marketed 23-valent pneumococcal polysaccharide vaccine provides large serotype coverage and offers a less expensive option. However, it is efficacious only in adults but not in infants. Conjugate vaccines offer a solution by generating immunological memory already at early age. A recently licensed 7-valent conjugate vaccine is immunogenic and efficacious in infants. Its serotype coverage might be sufficient in Europe and North America, but not in Africa, Asia and Oceania. A need exists to develop pneumococcal vaccines with lower cost and larger serotype coverage. Several 11-valent pneumococcal conjugate vaccines are being evaluated in phase I-III trials. This study reviews the current state of pneumococcal problem and pneumococcal vaccines in clinical use.     

Current concept of schizophrenia: state of the art

Approaches to diagnosing schizophrenia are different. There is a distinct tendency either to narrow the limits of the disease or to expand it, which in some cases leads to a disagreement and even a tendency to disputes. The comprehensive studies conducted in the Mental Health Research Center, Russian Academy of Medical Sciences, have provided an overall notion of the disease in terms of its progression and outcome. The clinical picture of schizophrenia is characterized by obligatory specific disorders, such as autism, reduced energy potential, emotional thinking, and behavioral disorders. Personality changes may be seen as the smoothening of specific personality traits and the appearance of the features that are not inherent to the patients in the past. Schizophernia is also characterized by positive psychopathological syndromes: pseudoneurotic, affective, psychopathy-like, hallucinatory-paranoid and catatonic. A study of 7500 patients with schizophrenia demonstrated that there were clear-cut regularities in the development of the disease, which suggest that there are forms and types in its progression. The study identified 3 forms of development: continuous, recurrent, and attack-like progressive with varying degrees and rates of the process (severe, moderate, and mild). Genealogical and clinicogenetic studies demonstrated accumulation of psychoses and abnormal personalities in the families of probands, manifest and slowly progressive forms of schizophrenia and cases of schizoid psychopathy. Among the wide spectrum of pathogenetic concepts, priority should be given to the dopamine hypothesis, whose main point is accumulation of an excessive amount of dopamine in the brain tissue, especially in the nigrostriatal, mesocortical, and mesolimbic systems. This may lead to activation of dopaminergic brain structures with an increase of dopamine receptors. This hypothesis is confirmed by the neuropathological studies demonstrating a significant increase in the numerical density of the dendritic spines and dendritic trunks in the with layer of the prefrontal cortex. The highest index of the numerical density was observed in young patients with prevalent negative disorders. Inasmuch as there is no correlation of this index with the duration of the disease, it can be concluded that the abundance of synaptical connections is a result of disturbed brain development and a factor predisposing to severe progression of schizophrenia. Treatment modalities are determined by the form and rate of progression of and the pattern of the psychopathological syndrome. Of particular importance is the role of age, somatic state, and individual sensitivity to neuroleptic drugs. Another important factor in the treatment of schizophrenia is a simultaneous or consecutive impact on the psychopathological syndrome and the disease as a whole.     

Current state of the art in myocardial tissue engineering

Myocardial tissue engineering aims to repair, replace, and regenerate damaged cardiac tissue using tissue constructs created ex vivo. This approach may one day provide a full treatment for several cardiac disorders, including congenital diseases or ventricular dysfunction after myocardial infarction. Although the ex vivo construction of a myocardium-like tissue is faced with many challenges, it is nevertheless a pressing objective for cardiac reparative medicine. Multidisciplinary efforts have already led to the development of promising viable muscle constructs. In this article, we review the various concepts of cardiac tissue engineering and their specific challenges. We also review the different types of existing biografts and their physiological relevance. Although many investigators have favored cardiomyocytes, we discuss the potential of other clinically relevant cells, as well as the various hypotheses proposed to explain the functional benefit of cell transplantation.     

Covert cognition in the persistent vegetative state

Brain damage can sometimes render a patient persistently unresponsive and yet apparently awake, admitting the possibility that the absence of overt voluntary behaviour might conceal a retained capacity for covert cognition. When given instructions to perform a cognitive task, a minority of patients in such a so-called persistent vegetative state (PVS) has recently been found to exhibit patterns of brain activation closely matching those observed in normal subjects obeying the same instructions. These data have been widely interpreted as implying the detection of covert “consciousness”. Here we show that this inference is not supported by the extant data because it relies on critical assumptions, obscured by conceptual unclarities, that are either untested or untestable. We set out the proper grounds for ascribing psychological attributes to PVS patients from physiological evidence of any kind, and offer a perspicuous conceptual framework for future empirical studies in the field.