青果微量元素的测定及其含量与功效的关系

用电感耦合等离子体发射光谱法(ICP—AES),同时测定了广州与潮州产青果中13种微量元素和宏量元素的含量,结果发现其含有多种人体必需和与乙型肝炎的发生发展有关的微量元素;初步讨论了它们与青果功效的关系。     

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.     

Otoconial alterations after embryonic development in hypergravity

The relation between prolonged hypergravity and structural adaptation of otoconia was studied in hamsters (n = 56). Three groups of hamsters (n = 27), were conceived and born in a centrifuge: group 1 (n = 10) 1 month under 2.5 G, group (2n = 9) 5 months under 2.5 G and 4 months under 1 G, group 3 (n = 8) 1 month under 2.5 G and 8 moths under 1 G. Control hamsters (n = 29) were conceived and born under 1 G (1 month old, n = 7; 9 months old, n = 22). Histological study of the otoconial layers (energy dispersive x-ray element analysis and scanning electron microscopy) showed similar calcium content, size, and shape in utricular and saccular otoconia in all groups. Different were the utricular otoconial size classes, large, medium-sized, a and small. The area with small otoconia increased in group 1 (p = 0.002). In group 2, the large otoconial area decreased (p < 0.001) and the medium-sized one increased (p < 0.001). In group 3, the large otoconial area decreased (p = 0.003) and the medium-sized one increased (p = 0.007). For age-related effects we found group 1 with an increased area of large otoconia (p = 0.001) and a decreased medium-sized one compared to groups 2 (p < 0.001) and 3 (p = 0.02). Hypergravity during formation of otoconia does not affect calcium content, size, or shape, but changes relative size of the areas with large, medium-sized, or small otoconia and the development of these areas. This resulted in a structural adaptation to hypergravity.     

新生鼠和成年鼠脑7种微量元素含量的比较

利用高频电感耦合等离子体原子发射光谱法（ICP－AES）测定Sprunge－Dawley大鼠新生期大脑皮层、海马、小脑、间脑和脑桥等部位的锌、铁、铜、锰、铬、锶、钼等7种微量元素的含量，并与成年动物做了比较。结果表明：（1）新生期大鼠全脑7种微量元素含量的多寡依次为：锌、铁、铬、锶、锰、铜、钼；成年期时钢跃居第四位，总含量低于新生期。（2）脑内不同部位微量元素的含量不同。新生大鼠海马和小脑内多数元素含量高于其他脑区，钼在间脑和海马中含量较高。成年鼠皮层、海马微量元素含量较高，皮层内铜、锶、钼含量最低。     

达格列净对2型糖尿病合并慢性心力衰竭患者微小RNA-423-5p的调控作用及心功能的影响研究

背景 糖尿病合并心力衰竭的患者数量庞大,达格列净作为新型降糖药物,目前已被指南推荐用于心力衰竭的治疗,但其改善心功能的作用机制还未完全明确。目的 研究达格列净对2型糖尿病（T2DM）合并慢性心力衰竭（CHF）患者血浆微小RNA-423-5p(miRNA-423-5p)表达的影响及其与心功能之间的相关性。方法 纳入2021-04-01至2021-11-30就诊于解放军第九六〇医院的T2DM合并CHF患者50例为研究对象,分为达格列净组（n=25）和对照组（n=25）,达格列净组给予达格列净10 mg/d,对照组给予其他降糖药物,余治疗原则相同,治疗6个月。另纳入同一时期于本院健康体检的心功能正常者为健康人群组（n=25）。通过数字病历系统收集患者的基本资料,包括年龄、性别、吸烟史、高血压史、血压水平、体质指数（BMI）、血脂、血糖、肌酐（Cr）、氨基末端脑钠肽前体（NT-proBNP）、丙氨酸氨基转移酶（ALT）、天冬氨酸氨基转移酶（AST）、纽约心脏病协会（NYHA）心功能分级、心脏彩超、合并用药情况,并留取血液标本进行miRNA-423-5p的检测。治疗4周进行门诊随访,收集患者心功...     

Kubicek每搏心输出量计算公式的三维有限元仿真研究

我们从 Kubicek模型三维有限元仿真的角度对 Kubicek每搏心输出量计算公式的临床应用价值进行了研究。在计算机仿真研究中 ,我们对比了模型仿真结果、具体采用 Kubicek每搏心输出量计算公式所得结果以及所设模型的理论计算结果。仿真结果表明 :模型中阻抗改变与主动脉中血液容积改变之间存在着近似的线性关系 ,证明了 Kubicek每搏心输出量计算公式具有一定的临床应用价值 ,同时也为心阻抗血流图基础理论提供了新的研究途径。     

基于图像的微阵列生物芯片分析

利用生物芯片的高通量特性，系统地研究生物体基因和蛋白质表达及其相互作用，在最近十几年迅速发展。以图像为基础的生物芯片分析是生物芯片技术的重要组成部分，对其方法进行研究已成为当前的热点之一。目前很多针对生物芯片的分析方法不断涌现，这些方法涉及网格定位、靶点分割、数据提取和表达、几何校正、噪声消除等生物芯片分析子过程。本研究对以上各类分析方法进行了综述，分析了各类方法的不同应用，比较了多种算法的分析结果，并提出当前在生物芯片分析研究领域需要解决的关键问题。     

Comparing non-hierarchical models: Application to non-linear mixed effects modeling

There is no method available to compare the fit of two non-hierarchical non-linear mixed effects models, although the common practice is to select the model with the lower objective function. Bootstrapping the log-likelihood differences (LLDs) of non-hierarchical models and constructing a bootstrap confidence interval on the LLDs is proposed for comparing the goodness-of-fit of such models. This is illustrated with different parameterizations of clearance models for an anti-infective agent in a longitudinal pharmacokinetic study which are compared. Additive and exponential models of creatinine clearance as a predictor of clearance are used as examples.     

Finite-element models of the human head

A review is presented of the existing finite-element (FE) models for the biomechanics of human head injury. Finite element analysis can be an important tool in describing the injury biomechanics of the human head. Complex geometric and material properties pose challenges to FE modelling. Various assumptions and simplifications are made in model development that require experimental validation. More recent models incorporate anatomic details with higher precision. The cervical vertebral column and spinal cord are included. Model results have been more qualitative than quantitative owing to the lack of adequate experimental validation. Advances include transient stress distribution in the brain tissue, frequency responses, effects of boundary conditions, pressure release mechanism of the foramen magnum and the spinal cord, verification of rotation and cavitation theories of brain injury, and protective effects of helmets. These theoretical results provide a basic understanding of the internal biomechanical responses of the head under various dynamic loading conditions. Basic experimental research is still needed to determine more accurate material properties and injury tolerance criteria, so that FE models can fully exercise their analytical and predictive power for the study and prevention of human head injury.