基于高阶累计量的肺音信号AR模型参数和双谱估计

根据肺音信号的非高斯随机特性,建立了肺胞系统非高斯ＡＲ模型。应用高阶累积量技术对肺音信号进行参数化双谱估计,并提取肺音源特征和肺胸系统传递函数。实验结果证实：肺音源由非高斯白噪声、周期脉冲序列和间歇性随机脉冲组成,肺胸系统相当于声低通滤波器,不同病理情况下的肺音双谱结构存在明显差异。该方法克服了肺音信号功率谱分析和经典双谱分析的缺陷与不足,可以为肺部疾病诊断提供更多和更客观的内在信息。     

基于高阶累计量的肺音信号AR模型参数和双谱估计

根据肺音信号的非高斯随机特性,建立了肺胸系统非高斯AR模型.应用高阶累积量技术对肺音信号进行参数化双谱估计,并提取肺音源特征和肺胸系统传递函数.实验结果证实:肺音源由非高斯白噪声、周期脉冲序列和间歇性随机脉冲组成,肺胸系统相当于声低通滤波器,不同病理情况下的肺音双谱结构存在明显差异.该方法克服了肺音信号功率谱分析和经典双谱分析的缺陷与不足,可以为肺部疾病诊断提供更多和更客观的内在信息.     

两种分形维数在颞下颌关节音分析中的应用

颞下颌关节（TMJ）是人体最复杂的关节之一,有着复杂的生理功能,颞下颌关节音（颚开合时TMJ产生的声音）含有丰富的有关TMJ状态的信息。利用非线性动力学的混沌与分形理论对健康人和颞下颌关节内紊乱（TMD）患者的TMJ音信号进行了分析。分别计算其波形维和相关维。结果表明,健康人TMJ音信号的两种分形维数值都明显高于TMD患者。提示,以TMJ音信号的分形维数值作为TMJ损伤及病变的一个指标是有意义的。     

基于柯氏音识别法的自动血压测量系统

市场上的电子血压计一般均采用示波法,采用间接测量原理,其准确性难以提高。柯氏音法是血压测量的金标准,有望提高自动血压测量准确性,但柯氏音的降噪和识别是难题。因此,提出了基于柯氏音识别法的自动血压测量系统,该系统解决了降噪和识别的难题,通过对实时柯氏音信号的测试表明该系统可以有效地识别出柯氏音,得出收缩压和舒张压,识别精度高。且该系统成本低廉,测试实验均造作于Android系统的手机上,易于实现社区血压的健康管理和远程监控。     

豚鼠大脑皮层听区的撤声诱发电位

本工作在除去了声音信号終止时所产生的有效瞬时声的条件下,研究了豚鼠大脑皮层听区的撤声誘发电位。給予的声音信号(主要为1000周/秒純音及白噪声)終止时的消减时間常数約为10毫秒。在戊巴比妥鈉麻醉的情况下,对純音的撤声誘发电位是明显地存在的。在不麻醉及用乙醚或氯醛醣麻醉的情况下,对純音的撤声誘发电位較不明显,但用亮度調制扫描同步积累的記录方法仍然能确定它的存在。声音信号的时程长短对撤声誘发电位的出現甚为重要;純音信号要长达130—180毫秒时,撤声誘发电位才开始出現,在信号时程长达220—400毫秒时电位达到最大的振幅(約为100微伏)。在同样情况下对白噪声的撒声誘发电位未能記录到。     

中国肺音蛛属2种记述（蜘蛛目：皿蛛科）

记述我国皿蛛科微蛛亚科新纪录属:肺音蛛属Latithorax Holm,1943;1新种:栖霞肺音蛛L.qixeiensis sp.nov。和1新纪录种:窄缝肺音蛛L.faustus (O.P.—Cambriage,1900)。     

人音猬因子相互作用蛋白基因与慢性阻塞性肺疾病

慢性阻塞性肺疾病是呼吸系统常见慢性疾病。该疾病的发病与环境及多基因变异有关。近年的研究显示,人音猬因子相互作用蛋白基因参与多个系统疾病的发生发展,尤其对于呼吸系统该基因与慢性阻塞性肺疾病发病密切相关,该基因上某些单核苷酸多态性与慢性阻塞性肺疾病易感性相关,且在慢性阻塞性肺疾病患者肺组织内存在该基因低表达。另外,该基因与FEV1和FEV1/FVC关系密切,对肺功能有保护作用。目前的研究提示该基因和音猬信号通路在肺胚胎发育、基因表达调控、细胞增殖、细胞凋亡和平滑肌修复等方面发挥着重要调控作用,为慢性阻塞性肺疾病发病机制的研究指明了方向。本文就人音猬因子相互作用蛋白基因与慢性阻塞性肺疾病相关性的研究进展作一综述。     

喜炎平佐治小儿社区获得性肺炎86例临床疗效分析

目的：总结喜炎平辅助治疗小儿社区获得性肺炎的临床治疗效果。方法：选择小儿社区获得性肺炎86例,随机分为治疗组44例和对照组42例,两组均予抗生素及支持对症等治疗,治疗组在规范治疗基础上加用喜炎平注射液。观察并记录两组患儿发热、咳喘、肺部啰音消失时间及住院天数。结果：治疗组在退热、平喘、消散肺部湿啰音及住院天数方面与对照组比较有显著性差异（P〈0.05）。结论：喜炎平辅助治疗小儿社区获得性肺临床疗效肯定。     

喜炎平佐治小儿社区获得性肺炎86例临床疗效分析

目的:总结喜炎平辅助治疗小儿社区获得性肺炎的临床治疗效果。方法:选择小儿社区获得性肺炎86例,随机分为治疗组44例和对照组42例,两组均予抗生素及支持对症等治疗,治疗组在规范治疗基础上加用喜炎平注射液。观察并记录两组患儿发热、咳喘、肺部啰音消失时间及住院天数。结果:治疗组在退热、平喘、消散肺部湿啰音及住院天数方面与对照组比较有显著性差异(P<0.05)。结论:喜炎平辅助治疗小儿社区获得性肺临床疗效肯定。     

绵羊肺腺瘤病毒中国NM株部分gag基因的克隆与序列分析

参照GenBank中已发表的绵羊肺腺瘤病毒的基因序列,设计合成一对引物,对绵羊肺腺瘤病毒(Jaagsiekte sheep retrovirus,JSRV)内蒙株的gag基因中主要编码CA蛋白的基因段进行PCR扩增,产物经琼脂糖凝胶电泳分析,呈现一条约897bp的特异条带,将其回收后克隆入pMD-18 T载体中,并进行序列测定与分析.结果表明,与南非株(基因序列号NC-001494)的gag基因序列比较,核苷酸同源性为83%,推导出的氨基酸同源性为84%.与美国株(基因序列号AF105220)的gag基因序列比较,核苷酸同源性为81.5%,氨基酸同源性为83%.这是我国首次报道的绵羊肺腺瘤病毒的gag基因的一段序列,为我国科研工作者进行更深入的研究奠定基础.     

Parametric representation of normal breath sounds.

The spectral content of normal tracheal and chest wall breath sounds has been calculated using the fast Fourier transform (FFT) (J. Appl. Physiol. 50: 307-314, 1981). Parameter estimation methods, in particular autoregressive (AR) modeling, are alternative techniques for measuring lung sounds. The outcome of AR modeling of 38 complete breaths picked up simultaneously over the chest walls and tracheae of five normal males was evaluated. The sounds were treated as noise, bounded by a quasi-periodic envelope generated by the cyclic action of breathing, thus causing the sounds to become inherently nonstationary. Normalization of the sounds to their corresponding variance envelopes eliminated the nonstationarity, an important requirement for most signal-processing methods. Subsequently, the AR model order was sought using formal criteria. Orders 6-8 were found to be suitable for normal chest wall sounds, whereas tracheal sounds required at least orders 12-16. Using orders 6 and 12, we compared the prominent spectral features of chest wall and tracheal sounds calculated by AR with those found in the spectra calculated by FFT. The polar representation of the AR roots, calculated from the AR coefficients, showed that normal lung sounds from a group of individuals are characterized by a low variability, suggesting that this method may provide an alternative representation of the sounds. The data presented here show that normal lung sounds, when measured in the frequency domain by either FFT or AR modeling, have a characteristic pattern that is independent of the analysis method.     

A method for computerized modification of certain natural animal sounds for communication study purposes

A new method for computerized modification of sound signals is presented. With digital signal processing in the time domain it is possible to alter the amplitude, the frequency and the time scale of natural sounds independently. The method can be applied to natural sounds with reasonably pure tonal quality.     

基于虚拟仪器技术的血管壁动态信息无创检测与辅助诊断系统

为了在体外无损地实现对血管壁动态信息、心电和心音信号等医学信息多参数的综合同步检测以及分析和处理,利用虚拟仪器技术设计了血管壁动态信息多参数的无创检测辅助诊断系统．该系统硬件平台由信号输入模块、信号调理模块以及采集卡等三大模块组成。软件系统由开发虚拟仪器的流行软件LabVIEW编写,实现了数据的采集、实时显示、分析处理和存储等。初步的临床检测结果证实了本无创检测系统的可行性和临床应用的前景,为功能性无创辅助诊断与血管壁弹性（硬化）程度有关的血管疾病提供了一种新的方法。     

Measurement and theory of wheezing breath sounds

We measured the time and frequency domain characteristics of breath sounds in seven asthmatic and three nonasthmatic wheezing patients. The power spectra of the wheezes were evaluated for frequency, amplitude, and timing of peaks of power and for the presence of an exponential decay of power with increasing frequency. Such decay is typical of normal vesicular breath sounds. Two patients who had the most severe asthma had no exponential decay pattern in their spectra. Other asthmatic patients had exponential patterns in some of their analyzed sound segments, with a range of slopes of the log power vs. log frequency curves from 5.7 to 17.3 dB/oct (normal range, 9.8-15.7 dB/oct). The nonasthmatic wheezing patients had normal exponential patterns in most of their analyzed sound segments. All patients had sharp peaks of power in many of the spectra of their expiratory and inspiratory lung sounds. The frequency range of the spectral peaks was 80-1,600 Hz, with some presenting constant frequency peaks throughout numerous inspiratory or expiratory sound segments recorded from one or more pickup locations. We compared the spectral shape, mode of appearance, and frequency range of wheezes with specific predictions of five theories of wheeze production: 1) turbulence-induced wall resonator, 2) turbulence-induced Helmholtz resonator, 3) acoustically stimulated vortex sound (whistle), 4) vortex-induced wall resonator, and 5) fluid dynamic flutter. We conclude that the predictions by 4 and 5 match the experimental observations better than the previously suggested mechanisms. Alterations in the exponential pattern are discussed in view of the mechanisms proposed as underlying the generation and transmission of normal lung sounds. The observed changes may reflect modified sound production in the airways or alterations in their attenuation when transmitted to the chest wall through the hyperinflated lung.     

Effect of subcutaneous fatty tissue on normal respiratory sounds]

Auscultation is an important, non-invasive and simple measure in the diagnosis of lung diseases that can detect sometimes pathological processes prior to radiography. Attempts have already been made to automatically detect characteristic pathological sounds, but a knowledge of potential influencing factors is a must for correct interpretation. In this study we have investigated the effect of the subcutaneous fat layer on normal lung sounds. This is of importance to determine corrective factors for the automatic detection of bronchial breathing in pneumonia. The lung sounds of 125 healthy people (55f, 70m) were digitally recorded at four different positions of the thorax (3. ICR paravertebral, 7. ICR medioscapular, all left and right). Evaluation was done separately for gender. The subcutaneous fat layer was measured with a Holtain Skinfold Caliper at the identical four recording positions. For a quantitative evaluation of the sounds we calculated the relative power of frequency bands 330-600 Hz and 60-330 Hz and their ratio. The relation between these parameters and the subcutaneous fat layer was analyzed with the Pearson correlation. The results of this study show that the influence of subcutaneous fat layer is negligible and can be ignored in the automatic detection of lung sounds.     

Automated identification of field-recorded songs of four British grasshoppers using bioacoustic signal recognition

Recognition of Orthoptera species by means of their song is widely used in field work but requires expertise. It is now possible to develop computer-based systems to achieve the same task with a number of advantages including continuous long term unattended operation and automatic species logging. The system described here achieves automated discrimination between different species by utilizing a novel time domain signal coding technique and an artificial neural network. The system has previously been shown to recognize 25 species of British Orthoptera with 99% accuracy for good quality sounds. This paper tests the system on field recordings of four species of grasshopper in northern England in 2002 and shows that it is capable of not only correctly recognizing the target species under a range of acoustic conditions but also of recognizing other sounds such as birds and man-made sounds. Recognition accuracies for the four species of typically 70-100% are obtained for field recordings with varying sound intensities and background signals.     

Spectral content of forced expiratory wheezes during air, He, and SF6 breathing in normal humans.

The effect of gas density on the spectral content of forced expiratory wheezes was studied in the search for additional information on the mechanism of generation of respiratory wheezes. Five normal adults performed forced vital capacity maneuvers through four or five orifice resistors (0.4-1.92 cm ID) after breathing air, 80% He-20% O2, or 80% SF6-20% O2. Tracheal lung sounds, flow, volume, and airway opening (Pao) and esophageal (Pes) pressures were measured during duplicate runs for each orifice and gas. Wheezes were detected in running spectra of lung sounds by use of a frequency domain peak detection algorithm. The wheeze spectrograms were presented along side expiratory flow rate and transpulmonary pressure (Ptp = Pao - Pes) as function of volume. The frequencies and patterns of wheeze spectrograms were evaluated for gas density effects. We found that air, He, and SF6 had similar wheeze spectrograms. Both wheeze frequency and patterns (as function of volume) did not exhibit consistent changes with gas density. Speech tone, however, was substantially affected in the usual pattern. These observations support the hypothesis that airway wall vibratory motion, rather than gas phase oscillations, is the source of acoustic energy of wheezes.     

Early detection of pulmonary congestion and edema in dogs by using lung sounds

Five mongrel dogs (2 interstitial and 3 alveolar edema) were studied. Lung mechanics were measured by recording the flow, volume, and esophageal pressure according to the standard technique. Edema was produced by infusion of Ringer lactate solution. Lung sounds were recorded on tape from the dependent part of the chest wall. Lung sound signals were high-pass filtered at 100 Hz and subjected to fast Fourier transform. Samples of lung sounds were analyzed before (control) and at 5, 10, 20, 30, and 40 min after the infusion. The mean, median, and mode frequencies of sound power spectra at the control time were, respectively, 169.6 +/- 29.19, 129.6 +/- 29.81, and 136.0 +/- 29.87 (SD) Hz. These values increased significantly at 5 min after infusion to 194.0 +/- 26.08 (P less than 0.0037), 150.2 +/- 23.48 (P less than 0.0085), and 164.6 +/- 28.74 Hz (P less than 0.02), respectively. These values stayed significantly elevated at 10, 20, 30, and 40 min. The pulmonary wedge pressure, lung dynamic compliance, and pulmonary resistance were measured also at the same times. The mean, median, and mode frequencies correlated with pulmonary wedge pressure (P less than 0.00001, P less than 0.0001, P less than 0.0001), lung dynamic compliance (P less than 0.001, P less than 0.0001, P less than 0.0001), and pulmonary resistance (P less than 0.00001, P less than 0.00001, P less than 0.0001), respectively. There were no significant adventitious sounds up to 40 and 50 min after infusion. We concluded that pulmonary congestion and early edema alter the frequency characteristics of lung sounds early, before the occurrence of adventitious sounds. These altered lung sounds may be used as an index of pulmonary congestion and impending edema.