超声乳化白内障吸除术后和囊外白内障摘除术后视功能比较

目的:本组资料比较白内障超声乳化吸除联合人工晶状体植入术(PHACO+IOL)和囊外摘除联合人工晶状体植入术(ECCE+IOL)这2种手术后患者视功能的变化。方法:作PHACO+IOL的患者98例,和作ECCE+IOL的患者77例,分别在手术前,手术后1周、1个月和3个月作眼科检查并完成视功能问卷。结果:在手术后1周,超声乳化组视功能得分及各指标得分均高于囊外摘除组(P<0.05);在术后1个月和3个月,超声乳化组视功能得分以及感觉适应和立体觉2个指标的得分高于囊外摘除组(P<0.05),对日常活动的限制和周边视野2个指标的得分2组差异无显著性意义(P>0.05)。结论:PHACO+IOL比ECCE+IOL有较大的视功能改善,特别是在感觉适应和立体觉方面,在对日常活动的限制和周边视野的改善方面,2种手术方式之间差异无显著性意义。     

基于配准方法的颅脑CT图像病变信息自动提取算法

医学图像中病变信息的计算机自动提取是实现计算机智能辅助诊断的关键与难点,本研究的目的就是提出一个解决该难题的算法,称之为PATHOINFER。该算法的基本过程是首先选择一幅具有代表性的模板图像帆和一系列与其相应的正常图像样奉Mi,利用非刚性配准分别建立表示“正常图像”灰度变化的灰度均值图谱,表示正常变异的统计概率图谱和反映其解剖结构空间关系的分割模板。以实现对“正常图像”的计算机描述。再通过M0与目标图像S的配准,达到“正常图像”与S在空间关系上的一致,然后通过S与“正常图像”的比较,利用模糊逻辑推理,自动检出S中的病变区域,并实现对其病变特征信息的自动提取。实验结果表明,PATHOINFER算法可自动地检出并分割病变区域,并能够自动地提取包括病变发生部位在内的特征信息。实现了计算机智能辅助诊断研究中病变信息自动提取的难胚。     

听觉诱发电位提取方法的研究与分析

论述了运用小波变换进行听觉诱发电佗单次提取的原理、方法和实验分析。结果表明，对单次试验信号，经小波变换及相关分析后，可从带自发脑电干扰的信号中提取诱发电位信号。小波变换分析方法与传统的叠加平均方法相比，可减少试验次数，缩短检测周期。     

Performance enhancement for audio-visual speaker identification using dynamic facial muscle model

Science of human identification using physiological characteristics or biometry has been of great concern in security systems. However, robust multimodal identification systems based on audio-visual information has not been thoroughly investigated yet. Therefore, the aim of this work to propose a model-based feature extraction method which employs physiological characteristics of facial muscles producing lip movements. This approach adopts the intrinsic properties of muscles such as viscosity, elasticity, and mass which are extracted from the dynamic lip model. These parameters are exclusively dependent on the neuro-muscular properties of speaker; consequently, imitation of valid speakers could be reduced to a large extent. These parameters are applied to a hidden Markov model (HMM) audio-visual identification system. In this work, a combination of audio and video features has been employed by adopting a multistream pseudo-synchronized HMM training method. Noise robust audio features such as Mel-frequency cepstral coefficients (MFCC), spectral subtraction (SS), and relative spectra perceptual linear prediction (J-RASTA-PLP) have been used to evaluate the performance of the multimodal system once efficient audio feature extraction methods have been utilized. The superior performance of the proposed system is demonstrated on a large multispeaker database of continuously spoken digits, along with a sentence that is phonetically rich. To evaluate the robustness of algorithms, some experiments were performed on genetically identical twins. Furthermore, changes in speaker voice were simulated with drug inhalation tests. In 3 dB signal to noise ratio (SNR), the dynamic muscle model improved the identification rate of the audio-visual system from 91 to 98%. Results on identical twins revealed that there was an apparent improvement on the performance for the dynamic muscle model-based system, in which the identification rate of the audio-visual system was enhanced from 87 to 96%.     

Safety and Effectiveness of Transvenous Lead Extraction in Octogenarians

Transvenous Lead Extraction . Introduction: As the population ages, the number of elderly patients with implantable cardiac devices referred for transvenous lead extraction will dramatically increase in Western countries. The safety and effectiveness of lead extraction in elderly patients has not been well evaluated. We report the safety and effectiveness of transvenous lead extraction in octogenarians. Methods and Results: From January 2005 to January 2011, we reviewed data from consecutive patients ≥ 80 years referred to our institutions for transvenous lead extraction because of cardiac device infection or lead malfunction. Clinical characteristics, procedural features, and periprocedural major and minor complications were compared between octogenarians and younger patients. Out of 849 patients undergoing lead extraction in the participating institutions during the study period, 150 (18%) patients were octogenarians (mean age 84 years; range 80–96; 64% males). A significantly higher percentage of octogenarians presented with chronic renal failure (55% vs 26%; P < 0.001), history of malignancy (22% vs 6%; P < 0.001), and chronic obstructive pulmonary disease (46% vs 19%; P < 0.001). Complete lead extraction rates were similar in the 2 age groups (97% in octogenarians vs 96% in patients <80 years; P = 0.39). Periprocedural death occurred in 2 (1.3%) patients ≥80 years and in 5 (0.72%) patients <80 years (P = 0.45 for comparison). No differences in terms of other periprocedural major and minor complications were found between the 2 age groups. Conclusion: Despite presenting with a significantly higher rate of comorbidities, transvenous lead extraction can be performed safely and successfully in octogenarians. (J Cardiovasc Electrophysiol, Vol. 23 pp. 1103‐1108, October 2012)     

Development and validation of a quantitative real time PCR assay for BK virus

Several studies have shown that BK viral load in plasma and urine are reliable markers for the detection of BK virus associated nephropathy (BKVAN) in renal transplant patients. We developed a quantitative real time PCR assay based on TaqMan technology for the measurement of BK viral load in plasma and urine. Considering the high similarity of the nucleotide sequence of the BK virus (BKV) with the JC virus (JCV), we designed this assay to specifically amplify BKV. We determined the viral DNA recovery rate on manual (QIAGEN's QIAamp DNA Blood Mini Kit) and automated (BioMerieux's NucliSENS EasyMAG) extraction methods. The comparison showed a higher viral DNA recovery rate on the automated extraction (61–76% in plasma and 52–65% in urine) as compared to the manual method (49–52% in plasma and 33–56% in urine). Quantitation of the viral load was performed using an external standard curve that was constructed with serial dilution of a plasmid containing the full length of the BKV genome. Commercially available quantitative BKV standards showed good correlation with the plasmid standard. The reproducibility of the assay was determined based on the Ct values of the amplified products as well as in BK copies per milliliter of sample. This assay is linear over a 7 log range (10 to 1 × 10⁷ copies per reaction), no cross-reactivity was detected with the closest-related polyomavirus JCV, as well as other viruses that may be found in immunocompromised patients, and human genomic DNA. The limit of detection of the assay is 300 copies per milliliter in both plasma and urine and the limit of quantitation is 1000 copies per milliliter using the NATtrol BK Virus Linearity Panel (ZeptoMetrix). This real time PCR assay provides a reliable and sensitive method for the quantitation of BKV in plasma and urine samples.     

不同试剂盒对乙脑病毒RNA提取效能的比较

目的比较常见的3种商售RNA提取试剂对乙脑病毒检测的相对效率、耗时和成本,为实验室应用及检测结果的评价提供依据。方法对乙脑病毒参考株悬液作10^-1～10^-4系列稀释,选用QIAGEN公司的QIAamp Viral RNA Mini Kit、Sangon生物公司的RNA提取试剂盒和Invitrogen公司的Trizol试剂3种核酸提取方法提取上述样本RNA．用TaqMan实时荧光定量反转录聚合酶链反应对其提取效率进行评价,并比较3种试剂（盒）的耗费时间和价格。结果对不同稀释度乙脑病毒样本的检测,均以QIAGEN公司QIAamp Viral RNA Mini Kit检测的敏感度最高。以该试剂盒的提取效率为100％,则Invitrogen和Sangon生物公司RNA提取试剂（盒）的提取效率分别为77．4％～86．8％和64．2％～74．1％。3种试剂（盒）对cDNA起始模板量的估计也有明显的影响,差别达到1～3个数量级,以QIAGEN公司的试剂盒最敏感。3种试剂（盒）提取RNA耗时分别为60min、100min和70min,价格效率比分别为46元、23元和20元。结论RNA提取试剂可影响JEV荧光定量PCR检测的结果,各实验室应根据实验目的和实验室条件．合理选择病毒RNA提取试剂盒。     

基于多生理信号的情绪初步识别

以生理信号分析为主,表情行为观察和情绪主观感受评价为辅,对多名被试的情绪进行识别.60名大学女生接受恐惧-快乐-轻松的情绪诱发,有效数据55名,对应每个情绪片段,根据信号标记以及GSR微分,截取1min的生理信号进行处理和分析,应用SPSS对各生理参数进行情绪的单因素方差分析,然后采用逐步多类判别法,提取特征参数以识别情绪.结果表明HR、HRV、R波、T波各生理参数对情绪较敏感;提取出HFP,HR max,PNN50,LF/HF,Ratio,LFP,Mean NN 7个特征参数,构建情绪判别函数Fuction1,Fuction2和Z1、Z2,Z3;轻松的判别正确率为88.0%,快乐的为92.0%,恐惧的为80.0%,总体判别正确率为86.7%.以生理信号分析为主,辅助表情行为观察和情绪主观感受报告,是一种有效的情绪识别方法,所得数据客观、准确,提高了情绪识别率.