广东地区副溶血性弧菌暴发分离优势血清型菌株的分子特征

目的 研究广东地区多宗副溶血性弧菌暴发分离的优势血清型(O3:K6、O1:Kut、O4:K8)株的毒素基因携带情况、“大流行群”株分布特征以及不同血清型株之间的相关性.方法 对2008-2010年23起副溶血性弧菌暴发患者临床样本和当餐食品分离的62株优势血清型进行tdh、trh基因检测及“大流行群”鉴定(GS-PCR...     

电子病历辅助临床诊断系统研究

为共享医生诊疗经验,从相似电子病历检索的角度探讨辅助诊断系统的建设,介绍系统功能模块组成和理论算法,包括主诉相似度、诊疗模式相似度、图像相似度、综合相似度计算算法。此方法能够较为全面地根据电子病历的内容计算相似度,检索出的电子病历为医生制订诊疗计划提供参考。     

当归药材中水溶性成分指纹图谱的分析

目的:本文收集22个不同产地、不同批次的当归,经形态学鉴定均为正品。建立了当归药材中水溶性成分的HPLC指纹图谱。实现了对当归中29个化学成分色谱峰的分离,获取了反映该药材整体的化学数据。方法:将所获化学数据进行化学模式识别研究。用系统聚类分析将当归样品分为两类,以夹角余弦或相关系数为测度,进行相似度计算。结果:以相似度0.80为限度,即相似度在0.80～1.00为第1类,相似度在0.80以下为第2类,与聚类分析结果一致,两种不同测度的相似度趋势一致。结论:在分析未知样品时,只需计算未知样品与标准样本间的相似度,即可对未知样品进行鉴定、分类和评价。     

Human visual object categorization can be described by models with low memory capacity

Studies of high-level models of visual object categorization have left unresolved issues of neurobiological relevance, including how features are extracted from the image and the role played by memory capacity in categorization performance. We compared the ability of a comprehensive set of models to match the categorization performance of human observers while explicitly accounting for the models' numbers of free parameters. The most successful models did not require a large memory capacity, suggesting that a sparse, abstracted representation of category properties may underlie categorization performance. This type of representation--different from classical prototype abstraction--could also be extracted directly from two-dimensional images via a biologically plausible early-vision model, rather than relying on experimenter-imposed features.     

Neural substrates for visual perceptual grouping in humans

Two experiments investigated the neural mechanisms of Gestalt grouping by recording high-density event-related brain potentials (ERPs) during discrimination tasks. In Experiment 1, stimulus arrays contained luminance-defined local elements that were either evenly spaced or grouped into columns or rows based on either proximity or similarity of shape. Proximity grouping was indexed by a short-latency positivity (110-120 ms) over the medial occipital cortex and a subsequent right occipitoparietal negativity. Grouping by similarity was reflected only in a long-latency occipitotemporal negativity. In Experiment 2, proximity grouping was examined when local elements were defined by motion cues, and was again associated with a medial occipital positivity. However, the subsequent long-latency negativity was now enhanced over the left posterior areas. The implications of these results to the neural substrates subserving different grouping processes are discussed.     

An alternative method to the evaluation of similarity factor in dissolution testing

This paper addresses an alternative method to the evaluation of similarity factor f₂ as a criterion for assessment of similarity between two in-vitro dissolution profiles as proposed in the SUPAC-IR Guidance (1995). Diltiazem hydrochloride Sustained-Release (SR) tablets were tested and the following independent-model dissolution parameters were used: t_10% dissolution time, t_25% dissolution time, t_50% dissolution time, mean dissolution time (MDT), dissolution efficiency (DE) at t₁₂₀, and at t₃₆₀. To compare the dissolution profiles, several release models were tested such as Higuchi, zero order, first order, Baker-Lonsdale, Hixson-Crowell, Weibull and Korsmeyer-Peppas. The similarities between two in-vitro dissolution profiles were assessed by pair-wise independent-model procedures such as difference factor (f₁), similarity factor (f₂) and Rescigno index (ξ₁ and ξ₂). The in vitro release kinetics of diltiazem hydrochloride sustained release tablets were evaluated using USP apparatus 2.     

The disposition of polychlorinated biphenyls (PCBs) differs between germ-free and conventional mice

The disposition of toxicants, such as polychlorinated biphenyls (PCBs), in germ-free (GF) vs. conventional (CV) mice has received little attention to date. Here, we investigate PCB levels in three-month-old female CV and GF mice exposed orally daily for 3 days to 0, 6, or 30 mg/kg body weight of the Fox River Mixture (FRM), an environmental PCB mixture. We euthanized animals 24 h after the final dose. PCB profiles in tissues differed from the FRM profile but were similar in tissues across all 4 PCB exposure groups. PCB levels in CV but not GF mice followed the difference in PCB dose. Importantly, PCB levels were higher in CV than GF mice exposed to the same dose. Hepatic cytochrome P450 enzyme or lipid levels did not explain these trends in PCB tissue levels. Thus, toxicity studies with CV and GF animals need to assess the toxicokinetics of the toxicant investigated.CapsulePCB levels are typically higher in conventional than germ-free mice exposed to the same dose of PCBs.     

Disrupted small-world brain network in children with Down Syndrome

ObjectiveTo explore how the global organization or topology of the functional brain connectivity (FBC) is affected in Down Syndrome (DS).MethodsAs the brain is a highly complex network including numerous nonlinearly interacted neuronal areas, the FBCs of typically developing (TD) children and DS patients were computed using a nonlinear synchronization method. Then the differences in global organization of the obtained FBCs of the two groups were analyzed, in all electroencephalogram (EEG) frequency bands, in the framework of Small-Worldness Network (a network with optimum balance between segregation and integration of information).ResultsThe topology of the functional connectivity of DS patients is disrupted in the whole brain in alpha and theta bands, and especially in the left intra-hemispheric brain networks in upper alpha band.ConclusionsThe global organization of the DS brain does not resemble a Small-World network, but it works as a random network.SignificanceIt is the first study on global organization of the FBC in DS.     

基于相似性网络技术挖掘丁书文教授治疗冠心病的处方用药规律＊

目的 相似性网络能够有效的发现处方群中的高度相似处方模块，可用于名中医的处方用药数据挖掘研究。本研究将丁教授多年的处方数据，利用处方相似性网络技术进行分析，探讨丁教授治疗冠心病的处方用药规律。方法 收集来自山东中医药大学附属医院门诊系统的丁书文教授治疗冠心病的8689个处方，采用处方相似性网络等数据挖掘方法对丁教授的处方进行分析。结果 本研究利用复杂网络分析方法获得了丁教授治疗冠心病的主要处方，提示益气养阴、活血通络是其治疗冠心病的主要治法；利用处方相似性和社团分析方法，发现了丁教授治疗难治性心绞痛、冠状动脉痉挛等兼症以及合并快速性心律失常、高血压病的用药规律，反映了丁教授治疗冠心病的“常法”与“变法”的诊疗思路。结论 处方相似性网络技术能够从大量医案中挖掘名中医诊疗的处方规律，为名中医传承研究提供服务。     

探讨AI用于食管癌危及器官自动勾画的可行性

目的 探讨人工智能用于食管癌危及器官自动勾画的几何学和剂量学精度。方法 首先，选择100例食管癌患者基于连心人工智能平台建立图像数据库，每个患者包含5个已经手工勾画的危及器官。然后将其他20例患者CT图像传入人工智能平台，系统自动勾画危及器官作为目标图像，与手工勾画的危及器官进行几何学和剂量学比较。最后，分别比较两种勾画方式所需的时间、体积差异、重合度指标、相似性系数和剂量学差异。结果 自动勾画比手工勾画左肺、右肺、心脏、肝脏和脊髓分别节省时间98.83%、94.55%、84.9%、77.96%和94.15%，两者差异有统计学意义（t=2.27、3.28、4.92、-1.39、0.21，P<0.05）。左肺、右肺、心脏、肝脏和脊髓体积差异分别为（5.58±2.53）cm³、（8.57±4.36）cm³、（0.97±0.34）cm³、（1.47±0.65）cm³和（0.73±0.21）cm³，DSC值为0.78~0.96，DSC>0.7，OR值为0.84~0.97，重合度好。自动勾画与手工勾画危及器官剂量学对比中，各项剂量学指标均符合临床要求，除右肺V₅的剂量学指标的差异有统计学意义（t=0.41，P=0.04<0.05），左肺，右肺，肝脏，心脏和脊髓的其他剂量学指标的差异均无统计学意义（t=-1.23~3.11，P>0.05）。结论 食管癌危及器官的自动勾画几何精度高，剂量学差异小，时间短。AI在临床中的应用，可以大大提升医师的工作效率。