原发性单纯性脑干出血52例临床研究

目的研究原发性单纯性脑干出血的病因、诊断、治疗、预后及预防。方法对52例原发性单纯性脑干出血的临床资料进行回顾性分析。结果预后良好25例，优良率为48．1％；死亡21例，死亡率40．4％；出血量≤5．0ml死亡率21．9％（7／32），出血量≥5．1ml死亡率70．0％（14／20），出血量〉10.0ml 10例全部死亡。结论原发性单纯性脑干出血发病急，病情重，死亡率高，预后差；高血压为本病的主要发病原因；CT是原发性单纯性脑干出血的安全、可靠诊断方法；适时进行气管切开及亚低温治疗能有效提高疗效及降低死残率；严格控制血压是预防原发性单纯性脑干出血的重要措施。     

Performance in population models for count data,part II: A new SAEM algorithm

Analysis of count data from clinical trials using mixed effect analysis has recently become widely used. However, algorithms available for the parameter estimation, including LAPLACE and Gaussian quadrature (GQ), are associated with certain limitations, including bias in parameter estimates and the long analysis runtime. The stochastic approximation expectation maximization (SAEM) algorithm has proven to be a very efficient and powerful tool in the analysis of continuous data. The aim of this study was to implement and investigate the performance of a new SAEM algorithm for application to count data. A new SAEM algorithm was implemented in MATLAB for estimation of both, parameters and the Fisher information matrix. Stochastic Monte Carlo simulations followed by re-estimation were performed according to scenarios used in previous studies (part I) to investigate properties of alternative algorithms (Plan et al., 2008, Abstr 1372 []). A single scenario was used to explore six probability distribution models. For parameter estimation, the relative bias was less than 0.92% and 4.13% for fixed and random effects, for all models studied including ones accounting for over- or under-dispersion. Empirical and estimated relative standard errors were similar, with distance between them being <1.7% for all explored scenarios. The longest CPU time was 95 s for parameter estimation and 56 s for SE estimation. The SAEM algorithm was extended for analysis of count data. It provides accurate estimates of both, parameters and standard errors. The estimation is significantly faster compared to LAPLACE and GQ. The algorithm is implemented in Monolix 3.1, (beta-version available in July 2009).     

关于引进双源CT的可行性分析

本文就双源CT的市场需求、特点和用途进行了详细分析,为医院引进双源CT提供参考。     

先天性心脏病患儿术后多脏器功能障碍的预后分析

目的 探讨小儿先天性心脏病(先心病)术后多脏器功能障碍(MODS)预后情况及其影响因素,为对此类患儿进行针对性护理提供依据.方法 收集先心病术后并发MODS 77例患儿的临床资料.结果 11例放弃治疗出院,66例中44例救治存活,22例死亡.出现时间最早、累及最多的脏器为心脏;病死率最高的为累及中枢神经系统的患儿(57.69%),其次是累及血液系统的患儿(55.56%);患儿的病死率与累及脏器的数量呈显著正相关(P＜0.01).死亡患儿手术体外循环时间和主动脉阻断时间显著长于存活患儿(均P＜0.05),术中意外及术后心肺复苏发生率显著高于存活患儿(均P＜0.05).结论 先心病术后患儿应加强心功能监护,特别是体外循环时间＞120 min,主动脉阻断时间＞60 min及术中发生过意外情况、术后采取过心肺复苏术的患儿;尽早采取有利措施避免其他脏器功能受损是提高患儿存活率的关键.     

Open mesh versus non-mesh repair of groin hernia meta-analysis of randomized trials leased on individual patient data

Abstract Background. The EU Hernia Trialists Collaboration was established to provide reliable evaluation of newer methods of groin hernia repair. It involved 70 investigators in 20 countries. Materials and methods. Twenty eligible trials (5016 participants) of open mesh vs. non-mesh groin hernia repair were identified. Meta-analysis was performed using raw individual patient data where possible. Results. Fewer hernia recurrences were reported after mesh repair. There were no clear differences between mesh and non-mesh groups in complications. Overall, those in the mesh groups had a shorter hospital stay, quicker return to usual activities and less frequent persisting pain, but individual trial results varied. Conclusions. The review provides strong evidence that open mesh repair is associated with a reduction in the risk of recurrence of between 50% and 75%. There is also some evidence of quicker recovery and of lower rates of persisting pain following open mesh repair. Electronic Publication     

A slim needle-shaped multiwire microelectrode for intracerebral recording

The construction of a needle-shaped multiwire microelectrode is described. It can be made with simple mechanical tools. The presented electrode assembly consists of 12 insulated nichrome wires (core diameter 25 μm) which are embedded in epoxylite resin. The straight-cut wire tips are aligned lengthwise and have a relative spacing of 150 μm. Outer dimensions vary from 100 × 180 μm at the level of the 1st electrode channel, to 100 × 100 μm at the level of the 12th channel at the tip. The configuration of this electrode was determined by its application: the laminar analysis of evoked potentials in the cortex of the rat. However, the number of channels, the diameter of the (nichrome) wire which determines the surface area of these channels, and the channel spacing can be easily adjusted during construction to meet other experimental requirements, such as the recording of single-unit activity. The electrode which is composed of biocompatible materials is suited for the study of field potentials and multiple-unit activity, in both acute and chronic experiments, and can be used repeatedly. To demonstrate the performance of the electrode assembly, a depth profile of field potentials is presented, accompanied by the corresponding current source density distribution. The potentials were recorded in the somatosensory cortex of the rat following stimulation of the median nerve under ketamine anesthesia.     

云纹技术在断裂分析中的应用

改进了传统的云纹数据处理方法,提出用曲面拟合方法处理云纹数据,提高了计算机处理云纹数据的效率与质量。又提出用云纹法测量J积分的技术,可望解决实际工程构件的J积分测量问题。     

Cross-calibration of liquid and solid QCT calibration standards: Corrections to the UCSF normative data

Quantitative computed tomography (QCT) has been shown to be a precise and sensitive method for evaluating spinal bone mineral density (BMD) and skeletal response to aging and therapy. Precise and accurate determination of BMD using QCT requires a calibration standard to compensate for and reduce the effects of beam-hardening artifacts and scanner drift. The first standards were based on dipotassium hydrogen phosphate (K₂HPO₄) solutions. Recently, several manufacturers have developed stable solid calibration standards based on calcium hydroxyapatite (CHA) in water-equivalent plastic. Due to differences in attenuating properties of the liquid and solid standards, the calibrated BMD values obtained with each system do not agree. In order to compare and interpret the results obtained on both systems, cross-calibration measurements were performed in phantoms and patients using the University of California San Francisco (UCSF) liquid standard and the Image Analysis (IA) solid standard on the UCSF GE 9800 CT scanner. From the phantom measurements, a highly linear relationship was found between the liquid- and solid-calibrated BMD values. No influence on the cross-calibration due to simulated variations in body size or vertebral fat content was seen, though a significant difference in the cross-calibration was observed between scans acquired at 80 and 140 kVp. From the patient measurements, a linear relationship between the liquid (UCSF) and solid (IA) calibrated values was derived for GE 9800 CT scanners at 80 kVp (IA=[1.15×UCSF]-7.32). The UCSF normative database for women and men obtained with the liquid standard was corrected for use with the solid standard. Proper procedures for cross-calibrating QCT measurements and the appropriate uses of normative data are discussed.