心电信号预处理方法研究

目的该文以临床心电信号和合成心电信号为数据样本,应用心电信号预处理方法在Matlab中进行数据仿真分析,以提高心电信号的信噪比。方法首先设计梳状滤波器消除工频干扰和基线漂移,再应用低通滤波器滤除频率大于200 Hz的高斯白噪声,最后进行合成心电信号和临床心电信号仿真测试。结果在合成心电信号仿真测试中,位于0 Hz和50 Hz的幅度得到较大的抑制;在临床心电信号仿真测试中,工频干扰和基线漂移的幅度由10×10~5变为2×10~5;经过低通滤波,高斯白噪声进一步被抑制。结论心电信号预处理方法能够较好地滤除心电信号中的干扰信号,提高了心电信号的信噪比,进而提高识别胎儿心电信号的准确率。     

1/fα噪声对计算混沌动力系统最大Lyapunov指数的影响

最大Lyapunov指数是诊断和描述动力系统混沌的重要参数。本文在仿真计算的基础上,发现1/fα噪声对计算混沌动力系统最大Lyapunov指数具有显著影响。在同一噪声水平下,白噪声的影响最为显著,随功率谱指数α的增大,其影响逐渐减弱;随着噪声水平的增加,1/fα噪声对计算混沌动力系统最大Lyapunov指数的影响越显著。当α≥2.0时,在噪声水平为0.2的情况下,计算得到的最大Lyapunov指数的误差小于10%。     

白噪声对听觉脑干电反应(ABR)和耳蜗电图(ECochG)的影响

本文通过20例听力正常人和10例听力正常豚鼠研究了白噪声对耳蜗电图(ECochG)和听觉脑干电反应(ABR)的干涉作用。实验结果表明,白噪声比短声(信号)的声强级低30dB(SL)以上时,     

小波变换方法检测胃动力

目的：研究胃动力检测的小波变换新方法。方法：用小波变换的方法对实测的胃运动信号根据需要进行低通或带通滤波。结果：比较精确地计算出进食后胃的半排空时间,检测出空腹胃运动信号的三相特征,从而可以判别被测对象是否为胃病患。结论：在应用小波变换处理胃电信号过程中,只要适当选取变换尺度就可以有效地消除原信号中高频噪声和基线漂移的影响。     

动态心电信号干扰的识别研究

目的研究能够有效滤除动态心电信号各种噪声和干扰,使有效信号得以突出的算法.方法分析动态心电信号干扰的形态特点及统计特点,针对不同种类的干扰提出识别办法,估算信噪比.结果本算法能有效估计信噪比的大小,有助于在心电监护中抛弃计算错误的导联,减小有效信号值估的偏差.结论本文算法具有较强的抗干扰能力,可靠性高,使监护系统能够有效地利用多导联的信息得到准确的分析诊断结果.     

基于HKY06A心音传感器的心音信号提取

目的:实现心音信号提取.方法:使用HKY06A心音传感器提取心音信号,使用双向检波及低通滤波实现心音包络的提取.结果:心音与心电的同步采集信号的对照显示该方法能够有效提取心音信号.     

基于独立分量分析的脉搏波信号的降噪处理

在血氧饱和度的无创监测过程中,由于采样得到的脉搏波信号信噪比较低,这给血氧饱和度的准确测量带来了困难,所以对于噪声干扰的去除是准确计算血氧饱和度的关键前提.本文利用基于信息极大判据的独立分量分析方法处理受白噪声干扰的脉搏波信号,实验证明该方法可以有效地分离脉搏波信号和噪声,为准确监测血氧饱和度奠定了基础.     

基于小波变换的心电图信号特征点的检测分析

目的:总结小波变换理论在心电图信号特征点检测中的价值。方法:基于小波变换多分辨分析理论,对心电信号进行去噪处理及,通过小波变换逼近信号对基线漂移进行滤除,滤除高频噪声,心电信号平均值设为0。分别采用时间电压法、面积法以及幅值法对平均心电轴进行测算。结果:面积法精确度最佳,显著高于其他两种方法(P0.05)。结论:以小波变换理论作为基础,应用面积法能够显著提高心电图信号特征点检测的准确性。     

基于观测噪声实时估计的卡尔曼滤波车窗防夹系统研究

卡尔曼滤波可有效解决电机参数变化对车窗防夹控制性能的影响。然而,由于观测噪声往往是未知并且随时间变化,这对基于卡尔曼滤波的车窗防夹控制系统性能有着重要的影响。本文利用小波变换可以对信号和噪声进行分离的特性,提出了一种基于观测噪声实时估计的电动车窗防夹控制方法。在Matlab环境下进行了建模和仿真,结果表明本文算法可以有效实现对观测噪声的实时估计,在不同的噪声条件下都达到了较好的控制效果。     

基于互信息极小判据的脉搏波信号的去噪处理

目的探讨血氧饱和度的无创监测过程中去除噪声干扰的方法。方法应用基于互信息极小判据的独立分量分析技术处理被白噪声污染了的脉搏波信号结果实验证明该方法可以有效地分离脉搏波信号和噪声,得到了平滑的脉搏波信号。结论这一信号处理方法为准确监测血氧饱和度奠定了基础。     

Value of D-Dimers in patients with acute aortic dissection

Objective: To evaluatel the value of D-dimers in patients with acute aortic dissection (AAD). Methods: This study consisted of 16 patients with AAD and 27 non-AAD patients. Serum D-dimets were measured by Sta-Liatest D-DI immunoturbidimetric assay. Results: D-dimer level was higher (P ＜ 0.001) in patients with AAD(7.91 ± 5.52 μg/ml) than that in non- AAD group(1.57±1.24 μg/ml). D-dimer was positive (＞0.4 μg/ml) in all patients with AAD and in 10 control group patients (37%). Among patients with acute AAD, D-dimers tended to be higher in Stanford A than in Stanford B (8.67 ± 4.31 μg/ml vs. 3.24±1.27 μg/ml, P ＜0.01). D-dimer values tended to be higher in more extended disease(3.84 ± 1.65 μg/ml, 8.57 ± 3.58 μg/ml and 11.87 ± 5.69 μg/ml in thoracic aorta, thoracic and abdominal aorta, thoracic and abdominal aorta and iliacal arteries, respectively, P ＜ 0.05 for both 8.57 ± 3.58 and 11.87 ± 5.69 vs. 3.84 ± 1.65 ). Including the control group into the analysis, we found a sensitivity of 100%, a negative predictive value of 100%, and a specificity of 66% and a positive predictive value of 64% for D-dimer in diagnosis of AAD in our patients with suspected AAD. Conclusion: D-dimer was elevated in patients with AAD. A negative D-dimer test result could be useful in excluding AAD.     

Research of combined liver-kidney transplantation model in rats

Objective： To set up a simple and reliable rat model of combined liver-kidney transplantation. Methods： SD rats served as both donors and recipients. 4℃ sodium lactate Ringer＇s was infused from portal veins to donated livers,and from abdominal aorta to donated kidneys, respectively. Anastomosis of the portal vein and the inferior vena cava （IVC） inferior to the right kidney between the graft and the recipient was performed by a double cuff method, then the superior hepatic vena cava with suture. A patch of donated renal artery was anastomosed to the recipient abdominal aorta. The urethra and bile duct were reconstructed with a simple inside bracket. Results： Among 65 cases of combined liver-kidney transplantation, the success rate in the late 40 cases was 77.5%. The function of the grafted liver and kidney remained normal. Conclusion： This rat model of combined liver-kidney transplantation can be established in common laboratory conditions with high success rate and meet the needs of renal transplantation experiment.     

BLOOD PRESSURE CHANGE WITH AGE IN SALT-SENSITIVE TEENAGERS

Objective To observe blood pressure change with age in salt-sensitive teenagers whose salt sensitivity were determined by repeated testing.Methods Salt sensitivity was determined through intravenous infusion of normal saline combined with volume-depletion by oral diuretic furosemide in 55 teenagers. After five years, salt sensitivity was re-examined and subject blood pressure was followed up. Blood pressure changes in salt-sensitive teenagers were compared to that of non-salt sensitive teenagers over five years.Results After 5 years, the repetition rate of salt sensitivity determined by intravenous saline loading is 92.7%. In teenagers with salt sensitivity on the baseline, both the systolic blood pressure increments and increment rates were much higher than non-salt sensitive teenagers (12.7±12.1 mmHg vs. 2.8±5.2 mmHg, P＜ 0.01; 12.2%± 12.0% vs. 2.5% ±4.4%, P＜ 0.001,respectively). There was a similar trend for diastolic blood pressure (8.4 ± 6.4 mmHg vs. 3.7 ± 6.4 mmHg, P = 0.052; 13.2% ±10.6 % vs. 6.8%± 10.1%, P = 0.053, respectively).Conclusions Salt sensitivity determined by intravenous saline loading showed good reproducibility. Blood pressure increments with age were much higher in salt-sensitive teenagers than non-salt sensitive teenagers, especially in terms of systolic blood pressure.     

安心颗粒对急诊经皮冠状动脉介入术后生活质量影响的研究

目的：评价使用安心颗粒对急诊经皮冠状动脉介入术（PPCI）术后生活质量的影响.方法：将160例接受PPCI的急性ST段抬高型心肌梗死患者随机分为安心颗粒组（术前顿服安心颗粒8.8g,术后安心颗粒4.4 g/次,每日2次）和对照组（仅接受基础药物治疗）.所有患者均服用阿司匹林、氯吡格雷和阿托伐他汀.分别在入院时、出院前1d、出院后180 d时,应用心肌梗死多维度量表（MIDAS）、中文版SF-36评价量表对患者生活质量评分.并观察术后30 d以内的出血并发症、血小板减少症发生情况.结果：入院时和出院前1d,两组患者的心肌梗死MIDAS、SF-36量表评分比较无差异（P＞0.05）;出院后180 d时,与对照组比较,安心颗粒组MIDAS、SF-36评分明显减低（P＜0.05）;组内与入院时比较,两组出院前1d、出院后180 d时,MIDAS、SF-36评分均降低（P＜0.05）.两组患者在随访期间均无大量出血、少量出血、重度和极重度血小板减少症发生,安心颗粒组有4例、对照组有7例发生不明显出血（P＞0.05）.两组发生轻度血小板减少症的患者数比较无差异（P＞0.05）.结论：PPCI使用安心颗粒,能改善急性ST段抬高型心肌梗死患者的生活质量,且不增加出血风险.     

The comparative studies of the influences of Urapidil and Nicardipine on sino-atrial node function, atrio-ventricular node function and hemodynamics

Objective:To investigate the influences of urapidil and nicardipine on rabbit sinus function,atrio-ventricular node function and hemodynamics.Methods:Thirty-two Angora's rabbits were selected and randomly divided into four groups.U1 group:urapidil 0.25 mg/kg;U2 group:urapidil 0.5 mg/kg;N1 group:nicardipine 10 μg/kg;N2 group:nicardipine 20 μg/kg.All these medicine were administrated within 30 seconds.Measurements were taken before and after the administration of urapidil or nicardipine for the following data:mean blood pressure(MAP),heart rate(HR),sino-atrial conduction time(SACT),maximal sinoatrial recovery time(SNRTmax)corrected sinus node recovery time(CSNRT),index of sinus node recovery time(SNRTI),Wenckebach A-V conduction frequency (WB),and P-R interval.Results:Significant MAP and HR changes were identified in all of the four groups before and after administration of both urapidil and nicardipine.No significant changes could be found in the rest of the parameters.Intergroup analysis showed that SACT and CSNRT of N1 and N2 groups were shorter than those of the U2 group(P＜0.01);the MAP decreased(P＜0.01)and the HR increased drastically(P＜0.01).Conclusions:Neither urapidil(0.25 mg/kg,0.5 mg/kg)nor nicardipine(10μg/kg,20μg/kg)has any significant influence on rabbit sinus function or rabbit atrio-ventricular node function.Nicardipine could be a better choice than urapidil for parafunctional sinus node patients.     

Expression of OPGmRNA and ODFmRNA in the patients of hip fracture due to osteoporosis

Objective：To investigate the gene expression of osteoprotegerin（OPG） and osteoclast differentiation factor（ODF） in the bone tissue of patients with hip fracture due to osteoporosis. Methods：OPGmRNA and ODFmRNA in the bone tissue in 50 cases of osteoporosis sufferers（over 50 years old） with hip fracture（Observer Group） and 30 cases of hip facture sufferers with no osteoporosis（Control group） were analyzed with the Semi-Quantitative RT-PCR method. Results：The mRNA expressed of ODF, OPG were both high in the patients with hip fracture. In the control group, the expression of OPG mRNA was observed, while the expression of ODF mRNA was very slight. Conclusion：Aged patients contained all signals including OPG, ODF that are essential for inducing osteoclastogenesis and promoting bone resorption.     

Dynamic Changes in Serum Estradiol and Progesterone levels in Patients of Premenstrual Syndrome with Adverse Flow of Liver-qi

Objective:To probe into the influence of changes of ovarian hormones on the pathogenesis of the specific sub-type premenstrual syndrome(PMS)and reveal partial microcosmic mechanisms of adverse flow of liver-qi.Methods:Estradiol(E2)and progesterone(P)levels in serum were determined at different phases of menstrual cycle by radioimmunoassay.Results:In the group of PMS with adverse flow of liver-qi.the secretive peak value Of E2 and P at the follicular phase significantly decreased,and the secretive peak value at the luteal phase did not come into being.Conclusions:Low E2 and P secretive peak at the follicular phase and absence of secretive peak at the luteal phase is one of the microcosmic mechanisms of PMS with adverse flow of liver-qi.One of the pathophysiologic mechanisms of specific sub-type PMS is probably the continuous low level of E2and P.     

Real-time Three-dimensional Echocardiography in Assessment of Left Ventricular and Right Ventricular Volumes

Real-time three-dimensional echocardiography (RT3DE)is a new ultrasound technique that enables dynamic threedimensional visualization and quantification of the heart in real time. Investigation of feasibility and methodology of RT3DE in determining left ventricular (LV) and right ventricular (RV) volumes, RT3DE was performed in 35 normal adults using Philips SONOS 7500 system with a 2-4 MHz matrix array transducer. The 60°×60° "pyramid" volume database was obtained and analyzed on a TomTec echo workstation. Both LV and RV volumes were calculated with four 3DE methods (i.e. apical 2, 4, 8, and 16-plane) through manually tracing ventricular endocardial borders in end diastole and end systole. Stroke volumes were then calculated. LV volume was also measured by 2DE Simpson's rule using GE VIVID 7 ultrasound machine.     

SCREENING FOR A 21-CHROMOSOME ABNORMALITY IN PREIMPLANTED EMBRYOS OF ELDERLY WOMEN

Increasing maternal age is the only etiological factor unequivocally linked to Down's syndrome in humans. The occurrence rate of newborns with Down's syndrome is about 1/220 in women over 35 years old. However, the occurrence rate in embryos fertilized in vitro, of the elder woman is unclear. Using FISH we screened the number of chromosome 21 in preimplanted embryos of 5 elderly women (average age, 38.4 years) to study the feasibility and necessity of screening trisomy 21 in embryos in patients over 35 years old at the in vitro fertilization (IVF) center.     

Scientific principles and rigorous processes should be followed in developing clinical guidelines for therapeutic interventions of integrative medicine

A clinical guideline for the therapeutic interventions of integrative medicine may be defined as a written document which states a series of recommendations on therapeutic interventions of integrative medicine for a special disease or condition. The guideline may provide assistance to medical professionals in making clinical decisions aimed at improving the clinical outcome of patients and reducing the costs of medical care（~＇4~. Recommendations issued by a guideline should be based on the best available evidence in both Western and Chinese medicine. For fulfilling this purpose, the development of clinical guidelines for therapeutic interventions in the field of integrative medicine should follow scientific principles and undergo a rigorous processes.