High-throughput single-cell analysis for enzyme activity without cytolysis

A novel high-throughput method without cytolysis for determination of enzyme activity inside single cells was developed by a combination of chemical cell perforation and an intracellular enzyme-catalyzed reaction. Peroxidase (PO) inside human neutrophils was chosen as the model system. Cells were perforated with digitonin to form micropores on the cell membrane. The perforated cells, with physiological buffer saline of pH 7.4 containing hydroquinone (H2Q) and H2O2, were continuously propelled by pressure through a capillary as the microsampler and microreactor. Small molecules H2Q and H2O2 could diffuse into the cell interior through the micropores on the cell membrane, and the large molecule PO remained in the cell interior. Intracellular PO converted H2Q into benzoquinone (BQ). BQ diffused out from the cell interior to the cell surface through the micropores and formed a BQ zone around the cell. The process proceeded in the capillary during cell movement. The BQ zones around every moving perforated cell were continuously delivered to the capillary outlet by hydraulic flow and detected. An average detection rate of >1 cell/min was obtained.     

计算化学在化学化工中的应用（上）

计算化学在最近十年中是发展最快的化学研究领域之一,通过对具体的分子系统进行理论分析和计算,能比较准确地回答有关稳定性、反应机理等基本化学问题。如今计算化学已被广泛用于材料、催化和生物化学等研究领域。主要就计算化学的背景、计算化学常用的方法及其在化学化工中的应用等几个方面作一简单介绍。     

Multi-source data fusion for economic data analysis

Neural Computing and Applications - Economic data include data of various types and characteristics such as macro-data, meso-data, and micro-data. The source of economic data can be the data...     

Sex and Race-Related DNA Methylation Changes in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the sixth most common cancer and fourth leading cause of cancer-related death worldwide. The number of HCC cases continues to rise despite advances in screening and therapeutic inventions. More importantly, HCC poses two major health disparity issues. First, HCC occurs more commonly in men than women. Second, with the global increase in non-alcoholic fatty liver diseases (NAFLD), it has also become evident that HCC is more prevalent in some races and/or ethnic groups compared to others, depending on its predisposing etiology. Most studies on HCC in the past have been focused on genetic factors as the driving force for HCC development, and the results revealed that genetic mutations associated with HCC are often heterogeneous and involve multiple pathogenic pathways. An emerging new research field is epigenetics, in which gene expression is modified without altering DNA sequences. In this article, we focus on reviewing current knowledge on HCC-related DNA methylation changes that show disparities among different sexes or different racial/ethnic groups, in an effort to establish a point of departure for resolving the broader issue of health disparities in gastrointestinal malignancies using cutting-edge epigenetic approaches.     

Enhanced Thermoelectric Performance of n-Type Organic Semiconductor via Electric Field Modulated Photo-Thermoelectric Effect

Modulating photophysical processes is a fundamental way for tuning performance of many organic devices. However, it has not been explored as an effective strategy to manipulate the thermoelectric (TE) conversion of organic semiconductors (OSCs) owing to their critical requirement to carrier concentration (>10¹⁸ cm⁻³) and the fact of low exciton separation efficiency in single element OSCs. Here, an electric field modulated photo-thermoelectric (P-TE) effect in an n-type OSC is demonstrated to realize a significant improvement of TE performance. The electrical and spectroscopy characterizations reveal that the electric field gating generates combined modulation of exciton separation, charge screening, and carrier recombination, which produces a more than ten times improvement of photoinduced carrier concentration. These coupled processes contribute to the unconventional Seebeck coefficient (S)-electrical conductivity (σ) trade-off relationship of the photoexcited films, therefore leading to a more than 500% enhancement in the power factor for n-type OTE semiconductors. This work opens a unique way toward state-of-the-art organic P-TE materials for energy harvesting applications.     

智能合约安全漏洞及检测技术综述

智能合约是去中心化生态中的重要组件,它降低了多方合作的信任成本,因而广泛应用于数字货币和金融等领域。智能合约在区块链上自动执行,具有不可修改和不可中止的特性,合约常常持有大量数字资产,一旦存在漏洞就有可能会造成巨大损失。随着智能合约技术的发展,合约漏洞开始从简单的语法漏洞向复杂的逻辑漏洞转变,触发漏洞的条件也可能从单一的交易演变为特定的交易序列。目前,各种针对合约的攻击层出不穷,因此开发出有效的合约漏洞检测工具显得尤为重要。为此,首先介绍了11个著名的智能合约漏洞;然后从静态分析和动态分析2个方面介绍了21个合约漏洞检测技术和工具,并从检测方法、研究对象、检测能力等方面对比这些工具,讨论了它们的优点和不足;最后,结合当前合约的安全现状展望了未来的研究工作。     

基于注入锁定法布里-珀罗型激光二极管的超宽带信号产生技术

提出了一种基于三波长注入法布里-珀罗型激光二极管(FP-LD)产生超宽带(UWB)信号的方案。在FP-LD不同激射模式中注入一路信号光和两路直流探测光,实现多波长变换并得到两路反码输出和一路正码输出;再通过光纤进行色散走离,使不同波长信号之间产生时延,形成UWB脉冲,最后经过光电转换产生UWB信号。对所提出的UWB信号产生方案的原理进行分析,并对UWB信号的波形以及频谱特性进行了实验研究。在此基础上,进行了1.25Gb/s非归零码(NRZ)信号注入FP-LD产生差分编码UWB信号的实验。实验产生的UWB脉冲信号半峰全宽最小为83.3ps,10dB谱宽约为4.6GHz,其频宽比为107%。     

一种新型扫频仪的设计

选用了一种基于DSP与FPGA结构的新型射频扫频仪的设计方案,重点讨论了其扫频信号源的设计.分析了频率合成技术的发展趋势,介绍了PLL技术和DDS技术的原理,并在此基础上给出了以PLL+DDS方式实现的扫频信号源设计.     

基于相关变量分解的重要性测度分析新方法

为了清晰地掌握相关输入变量情况下响应量方差的来源,有必要将重要性测度分离为相关部分和独立部分。通过将相关变量构造为独立变量的线性组合,相关输入变量对功能响应的方差贡献可被分离为相关部分和非相关部分,提出线性响应量情况下基于相关变量分解的重要性测度分析方法。所提方法不仅能将某一相关变量对响应的方差贡献分解为独立部分和相关部分,还可将其相关贡献分离为其与每一相关变量间的相关贡献分量。在此基础上针对非线性响应量的情况建立了基于迭代一阶泰勒展开的重要性求解方法,该方法可在响应的一阶泰勒展开式的方差与原响应方差基本一致的情况下对相关变量进行重要性测度求解。采用所提方法,对文中数值算例和工程应用算例中各相关输入变量的相关部分和独立部分的重要性测度指标进行了求解,证明了文中提出的基于相关变量分解的重要性测度方法是合理、可行的。