The Use of Molecular Dynamics Simulation Method to Quantitatively Evaluate the Affinity between HBV Antigen T Cell Epitope Peptides and HLA-A Molecules

Chronic hepatitis B virus (HBV), a potentially life-threatening liver disease, makes people vulnerable to serious diseases such as cancer. T lymphocytes play a crucial role in clearing HBV virus, while the pathway depends on the strong binding of T cell epitope peptide and HLA. However, the experimental identification of HLA-restricted HBV antigenic peptides is extremely time-consuming. In this study, we provide a novel prediction strategy based on structure to assess the affinity between the HBV antigenic peptide and HLA molecule. We used residue scanning, peptide docking and molecular dynamics methods to obtain the molecular docking model of HBV peptide and HLA, and then adopted the MM-GBSA method to calculate the binding affinity of the HBV peptide–HLA complex. Overall, we collected 59 structures of HLA-A from Protein Data Bank, and finally obtained 352 numerical affinity results to figure out the optimal bind choice between the HLA-A molecules and 45 HBV T cell epitope peptides. The results were highly consistent with the qualitative affinity level determined by the competitive peptide binding assay, which confirmed that our affinity prediction process based on an HLA structure is accurate and also proved that the homologous modeling strategy for HLA-A molecules in this study was reliable. Hence, our work highlights an effective way by which to predict and screen for HLA-peptide binding that would improve the treatment of HBV infection.     

Characterisation of rare earth minerals with field emission scanning electron microscopy

Abstract

Rare earth elements are becoming increasingly in demand, due to their prevalence in both renewable energy devices and high end electronics. The characterisation of the composition and morphology of the various phases that have valuable rare earth elements in the ores are needed in conjunction with the study of their physicochemical properties to optimise industrial process to extract the minerals containing the rare earth elements. Rare earth bearing minerals contain many elements with overlapping X-ray peaks (L- and M-lines) with an energy dispersive spectrometry detector, requiring a high degree of X-ray energy resolution. A program was developed to obtain the intensity of each peak by deconvolution of the X-ray spectrum. Low accelerating voltage of less than 5 kV and small beam diameter of less than 10 nm of a cold field emission scanning electron microscope allow x-ray microanalysis on the nanometre scale. A 100 nm wide phase was observed at 4 kV on a backscattered electron micrograph. Furthermore, a small beam diameter of less than 10 nm was used for identification of small phases of a few micrometres.

Les éléments de terre rare sont de plus en plus en demande, grâce à leur prévalence tant dans les dispositifs d’énergie renouvelable que dans l’électronique de haute gamme. On a besoin de caractériser la composition et la morphologie des différentes phases qui contiennent des terres rares de valeur dans les minerais, en combinaison avec l’étude de leurs propriétés physico-chimiques, afin d’optimiser le procédé industriel d’extraction des minéraux contenant les terres rares. Les minéraux porteurs de terre rare contiennent plusieurs éléments ayant des pics de rayons x qui se chevauchent (lignes L et M) avec un détecteur de spectroscopie à dispersion d’énergie, nécessitant une haute résolution énergétique. On a développé un programme visant à obtenir l’intensité de chaque pic par déconvolution du spectre de rayons x. Un faible voltage d’accélération de moins que 5 kV et un faisceau à faible diamètre de moins que 10 nm d’un microscope électronique à balayage par cathode froide permettent la microanalyse des rayons x à l’échelle du nanomètre. On a observé une phase de 100 nm de largeur à 4 kV sur une micrographe d’électrons rétrodiffusés. De plus, on a utilisé un faisceau de faible diamètre de moins que 10 nm pour l’identification de petites phases de quelques μm.     

Study on electrothermally actuated cantilever array for nanolithography

Nanolithography is a patterning technique for the fabrication of nano-scale structures.A promising method of nanolithography known as scanning probe lithography has particularly extensive applications for its high resolution,high reliability,and simple operation.In this paper,a novel electrothermally actuated cantilever with integrated heater,thermal conductor and actuator for scanning probe lithography is proposed.Cantilevers are designed in an 8×4 array.Analytical models are presented to simulate the temp...     

8279集成芯片在铝电解智能槽控机上的应用

8279芯片是专用数码显示器接口芯片,能对显示器自动扫描,并大大减轻CPU的负担。因此,在单片机应用系统中,获得了广泛的应用。主要阐述了8279芯片的主要结构、原理以及在铝电解智能槽控机的硬件组成、应用软件上的初始化、软件构成。     

超短脉冲激光对无机硅材料的损伤

通过控制作用于材料表面的激光能量和脉冲数量,实验研究了800nm,50fs,1kHz激光作用下融石英玻璃和硅片的破坏机制和损伤规律,计算了材料的损伤阈值与脉冲能量以及脉冲数量的依赖关系,并采用简化的理论模型计算了熔石英玻璃材料的损伤阈值与激光脉宽以及光子能量之间的依赖关系。对这两种无机硅材料在飞秒脉冲作用后的微区结构改变进行了扫描电子显微镜(SEM)测试,研究了其形貌特征。结果表明,硅片是由缺陷中的导带电子作为种子电子引发雪崩电离导致材料损伤,而熔石英玻璃是由多光子电离激发出导带电子引发雪崩电离导致材料损伤。     

新型光学成像技术及其在生物医学中的应用

本文介绍了在生物医学中有广泛应用前景的共焦扫描光学显微镜、扫描近场光学显微术和光学相干微术三种新型成像技术的基本原理和应用。     

扫描隧道显微镜中的扫描驱动器

概述了扫描隧道显微镜的工作原理,给出了采用压电材料的扫描控制方案及获取样品表面形貌信号的方法,介绍了系统中的ｚ扫描驱动器,ｘｙ扫描驱动器（扫描平台）及其非线性修正方法。     

基于超声扫描的塑封器件缺陷判定方法研究

超声扫描检测因为其灵敏度高、对样品没有损伤的特点,被广泛地应用到塑封器件的筛选和检测中,但是目前不存在一个完整的超声扫描检测方法。对塑封器件缺陷进行分析,提出一种塑封器件缺陷的超声扫描检测方法。该方法采用A扫描与C扫描检测塑封器件内部的缺陷,其过程为塑封体缺陷检测与重要界面缺陷检测。与现有GJB 4027A要求的聚焦6个重要界面的检测方法相比,本方法只需要聚焦两个界面即可观察到6个界面的情况,可以提升检测效率。     

完全基于边缘信息的目标靶快速分割算法

为了快速准确地分割提取目标靶,实现实时处理要求,提出了完全基于边缘信息的目标靶快速分割算法。首先采用基于邻域权值的非极大值抑制法细化Canny算子检测的边缘,并引入断点检测思想,通过构建追踪区域实现断点边缘追踪及连接,而后通过设置四向扫描长度总阈值,对边缘像点实行四向同步扫描填充,最终实现目标区域的准确分割。实验结果表明:相比其他分割算法,本文算法在分割正确率上具有较大优势,且采用较强的并行运行策略,提高了运行效率,达到了目标靶分割提取的实时性要求。     

基于面阵凝视扫描成像的声光光谱成像系统及其图像拼接验证试验

可见---近红外波段(400~1000 nm)成像光谱仪是光谱探测的重要组成部分。基于地基可见-近红外成像光谱仪的实际应用要求,提出了一种采用面阵探测器的凝视扫描成像光谱仪。该光谱仪还采用了一种新型分光器件声光可调谐滤波器(Acousto-optic tunable filter, AOTF)。其特点在于光谱的选择和施加在它上的射频信号频率相关;通过程序控制射频信号,就可以控制光谱。利用设计的光谱成像原理样机进行了地基月球观测实验。基于实验的特点,在光学设计的基础上增加了另一路共轴辅助光学,以进行粗定位。在获取成像结果之后,进行了辐射定标和尺度不变特征变换(Scale Invariant Feature Transformation, SIFT)图像拼接处理。结果表明,利用二维指向机构和面阵凝视成像系统,结合SIFT图像拼接算法,可有效获取宽幅高分辨率光谱图像。