Peak Identification in Visual Evoked Potentials

Waveform patterns evoked by 4 intensities of flash in normal subjects were studied in relation to intersubject variability. Time-frequency distribution curves of all peaks occurring between 11 and 280 msec after flash onset and meeting minimal criteria were obtained from 46 males. These distributions closely corresponded to similar data reported by others for single intensity stimulation. An algorithm was developed which identified in 67 to 100% of instances a single “peak event’ within the time ranges of each of 6 peak distributions. Many peak events appeared and disappeared within the 4 intensity sets of individuals. Latencies were obtained for these peak events. Application of the algorithm to a replicate sample of 29 Ss, which included 8 females, indicated generalizability. Test-retest data on 15 Ss showed its reliability. The data suggest that methodology significantly contributes to the variability of peak identification among subjects. This may be reduced by employing multiple intensities of stimulation.     

Cephalometric image analysis and measurement for orthognathic surgery

Automatic identification of landmarks in cephalometry is very important and useful for orthognathic surgery. A computerised automatic cephalometric analysis system (CACAS), based on image processing, is presented. For an original X-ray image, median filtering and histogram equalisation are used to improve image quality. The edge of an X-ray image is detected by a wavelet transform and Canny filter. Seventeen landmarks in cephalometry are successfully identified by knowledge-based edge tracing and changeable templates. Seventy-three measurements based on distances, angles and ratios between landmarks are computed automatically. The reliability of the landmarks and the validity of the measurements are compared for automatic and manual operation. The values of measurements obtained by CACAS are more precise and reliable: the mean error for linear measurements is less than 0.9 mm; the mean error for angular measurements is less than 1.2°. The rate of validity is over 80%, even if the image quality is poor. For an image with a high signal-to-noise ratio, the rate of validity of landmarking and measurements using the CACAS system is over 90%.     

Use of a multiplex PCR-based reverse line blot (mPCR/RLB) hybridisation assay for the rapid identification of bacterial pathogens.

The aim of this study was to develop a sensitive and reliable method for the molecular identification of pathogenic bacteria. A multiplex PCR-based reverse line blot (mPCR/RLB) hybridisation assay was developed and evaluated for the rapid identification of 24 systemic and respiratory bacterial pathogens in routine diagnosis. All species-specific probes designed for the RLB hybridised with amplified DNA only from the corresponding species. Sensitivity limits of the mPCR/RLB assay varied among the 24 target organisms from 0.05 pg to 0.5 ng of genomic DNA. The sensitivity of the assay was 2 x 10(2) CFU/mL for Streptococcus pneumoniae and 6 x 10(2) CFU/mL for Escherichia coli. The specificity of each probe was tested against 24 species. There were no cross-reactions among any of the 43 probes. The mPCR/RLB assay appeared to be a useful alternative tool for the molecular identification of common pathogens.     

Evolution, antimicrobial susceptibility and assignment to international clones of methicillin-resistant Staphylococcus aureus isolated over a 9-year period in two Spanish hospitals

Antimicrobial resistance profiles, restriction fragment length polymorphism of the coagulase gene and repetitive element sequence-based PCR were used to classify 210 methicillin-resistant Staphylococcus aureus isolates recovered between 1997 and 2005 in two hospitals in Vigo, north-west Spain. Representative isolates belonging to the epidemic clones were analysed by spa typing and multilocus sequence typing, and the staphylococcal chromosomal cassette (SCC)mec type was determined for all isolates. The New York/Japan clone (t002-ST5-II) was detected in Spain for the first time. However, the New York/Japan and the Brazilian (t037-ST239-IIIA) clones were replaced by EMRSA-16 (t018-ST36-II), which at present is the predominant clone.     

Extraction of organic acids by ion-pair extraction with tri-n-octylamine - VIII. Identification of synthetic dyes in pharmaceutical preparations

Synthetic dyes were extracted from syrups, oral suspensions, tablets, gelatin capsules, suppositories and granules by ion-pair formation with tri-n-octylamine (TnOA) and back-extracted with perchlorate ions. Identification was performed by TLC on cellulose layers and by reversed phase ion-pair HPLC.     

Model identification and estimation of organ-function parameters using radioactive tracers and the impulse-response function

Examination of the input-output events in functioning organs by the use of the impulse-response function (IRF) for a radioactive tracer is gaining more and more ground in nuclear medicine. This study summarizes the development of deconvolution analysis, laying special stress on the model-free approach. System linearity and time invariance are discussed, and means of eliminating noise in IRFs originating from the input and organ-time-activity curves are outlined. Typical IRFs are illustrated by flow diagrams, time-domain curves, and their representation by Laplace transforms. The cases of nondiffusible and diffusible tracers as well as parenchymally extracted and transported substances are discussed. Methods for the derivation of models and for the calculation of physiologically important parameters from theIRFs are suggested.At present, a guest scientist at the Institute for Medicine, Nuclear Research Center Jülich, Jülich, Federal Republic of Germany     

基于转录组数据的半夏AP2/ERF基因家族鉴定及逆境响应分析

目的：鉴定并研究半夏AP2/ERF转录因子的功能,为推进半夏品种的遗传改良提供理论依据。方法：该文基于半夏三代转录组数据鉴定了半夏中AP2/ERF家族成员,并对其进行系统的生物信息学分析,同时利用实时荧光定量聚合酶链式反应（Real-time PCR）检测半夏AP2/ERF在不同组织及不同胁迫条件下的表达情况。结果：通过转录组数据共筛选出8个全长AP2/ERF转录因子家族成员,归为AP2、ERF和DREB 3个亚家族;半夏AP2/ERF的氨基酸数目为251～512个,等电点为5.29～11.72,不稳定指数为45.90～82.41,且主要定位于细胞核中;半夏AP2/ERF基因的结构域和Motifs相对保守。组织特异性表达模式分析显示,半夏AP2/ERF基因在不同组织部位中具有不同的表达模式,且主要在叶中表达。逆境胁迫应答分析表明,PtERF1主要响应NaCl的胁迫诱导;PtERF2和PtERF4在低温和聚乙二醇（PEG）胁迫下表达量均有较大幅度的上调;PtERF3同时响应低温和NaCl两种逆境的诱导;PtERF5同时响应高温、低温、NaCl、PEG胁迫诱导;PtERF7在高温胁迫下表达...     

电子鼻技术应用于白及及其近似饮片快速辨识的可行性分析

目的：探讨电子鼻技术应用于白及及其近似饮片快速辨识的可行性。方法：收集134批白及及其近似饮片（白及45批、天麻30批、玉竹30批、黄花白及29批）作为待测样品,使用PEN3型电子鼻采集样品嗅觉感官数据作为自变量X,基于2020年版《中华人民共和国药典》和地方标准的鉴别结果,以及各饮片高效液相色谱法（HPLC）指纹图谱和原始采购信息,获得辨识模型的标杆数据Y,分别采用主成分分析-判别分析（PCA-DA）、偏最小二乘法-判别分析（PLS-DA）、最小二乘法-支持向量机（LS-SVM）及K-最近邻（KNN）4种化学计量学方法建立45批白及与89批非白及的二分类辨识模型和上述4种饮片的四分类辨识模型Y=F(X)。结果：经留一法交互验证,在二分类辨识中,上述4种模型分类正判率分别为97.01%、97.01%、98.51%和97.01%;在四分类辨识中,这4种模型分类正判率分别为97.76%、89.55%、98.51%和97.01%。二分类和四分类辨识模型的最高正判率均可达到98.51%,且均以LS-SVM算法为最优,最优核函数分别选择径向基核函数和线性核函数。最优模型判别结果良好,没有未分类样...     

MALDI-TOF MS在儿童血培养阳性病原菌快速鉴定中的应用

目的建立快速、准确的儿童血培养阳性病原菌鉴定方法,缩短血流感染鉴定时间,评估临床试验可行性。方法运用分离胶法提取阳性血培养瓶中富集的菌落,利用基质辅助激光解析电离飞行时间质谱分析(MALDI-TOF MS)对经过一系列前处理后的血培养阳性标本进行鉴定,并与病原菌纯培养鉴定后的结果对比,比较MALDI-TOF MS快速鉴定方法的符合率。结果100例血培养阳性样本中,除3例假阳性标本及3例混合感染标本外,以快速鉴定修正后的评分标准,MALDI-TOF MS快速鉴定方法与病原菌纯培养鉴定方法符合率达89.0%(81/91)。革兰阳性球菌、革兰阴性杆菌鉴定符合率分别为96.2%(50/52)、92.6%(25/27);而真菌的符合率不够理想,7株真菌中仅3株鉴定相符、符合率为42.9%。结论儿童血培养阳性标本的MALDI-TOF MS快速鉴定方法,对血流感染中致病菌的鉴定准确率高、耗时短,具有临床应用可行性,可满足临床早期、快速诊断血流感染致病菌的需求,但是对于真菌样本的前处理方法有待提高。     

新发传染病鉴定技术研究进展

近年来,人与野生动物日益频繁的接触,再加上病原微生物本身不断的变异和进化,导致新发传染病(emerging infectious diseases,EIDs)的发生呈持续增长态势,暴发频率不断增加,给全球公共卫生带来极大威胁与挑战。在下一次新发传染病暴发之际,希望能通过合理运用相关技术方法准确快速回答“病原体是什么”、“病原体来自哪”两大问题,从而及时有效预警并从源头控制新发传染病的大流行。对当前新发传染病病原体的鉴定技术进行归纳介绍,并探讨各种技术的优劣势以及各自应用领域。