芦蒿总黄酮的提取工艺优化及抗炎活性研究

目的:优化芦蒿总黄酮(Artemisia selengensis Turcz. total flavonoids,ATTF)提取的工艺条件,并研究其提取物抗炎活性。方法:采用响应面分析法中的中心组合设计方法(central composite design,CCD),建立以复合酶用量、超声温度、乙醇体积分数和液料比对ATTF得率影响的二次回归模型。采用脂多糖(LPS)诱导RAW264. 7巨噬细胞分泌一氧化氮(NO)建立细胞炎症模型,加入不同浓度的ATTF提取物,用NO试剂盒测定NO的分泌量。结果:芦蒿总黄酮的最佳提取工艺条件为复合酶(纤维素酶与果胶酶)用量1.5%、超声温度50 ℃、乙醇体积分数70%、液料比40:1 (mL/g),在此条件下,ATTF的得率为13.09%±2.13%。ATTF提取物中、高剂量组能够明显抑制脂多糖(lipopolysaccharide,LPS)诱导的RAW264.7巨噬细胞NO的分泌。结论:该回归模型有极显著性,可以用来合理预测ATTF的得率;ATTF提取物可以通过抑制巨噬细胞NO的分泌而发挥抗炎作用。     

菊苣多糖对免疫抑制小鼠免疫功能的影响

目的：研究菊苣多糖（chicory polysaccharide,CP）对免疫抑制小鼠免疫功能的影响。方法：ICR小鼠随机分为空白组、模型组、药物组（脾氨肽）、CP低、中、高剂量组。除空白组外,其余各组用环磷酰胺造成免疫抑制小鼠模型。分别测定各组小鼠体质量、免疫器官指数、外周血白细胞和红细胞数量、迟发型超敏反应致小鼠足趾肿胀度、腹腔巨噬细胞吞噬能力、血清血溶素水平及血清中白细胞介素2（IL-2）、白细胞介素6（IL-6）以及肿瘤坏死因子α（TNF-α）的活性水平。结果：与模型组相比,CP高剂量组能显著提高免疫抑制小鼠的净体质量增率、免疫器官指数、巨噬细胞吞噬率和吞噬指数、白细胞和红细胞数量以及降低足趾肿胀度（P<0.05）。同时,CP高剂量组还能明显提高小鼠腹腔巨噬细胞吞噬能力、血清溶血素含量,调节免疫抑制小鼠的免疫细胞因子。结论：CP对免疫抑制小鼠具有增强免疫活性的作用。     

浅谈计算机病毒及其防范

计算机病毒可以渗透到信息社会的各个领域,给计算机系统带来了巨大的破坏和潜在的威胁。为了确保信息的安全与畅通,因此,研究计算机病毒的防范措施已迫在眉睫。本文从计算机病毒的特点入手,来初步探讨对付计算机病毒的方法和措施。     

POTDR振动传感系统的数据处理与分析方法

偏振敏感光时域反射仪(POTDR)可用于检测光纤中背向传输瑞利散射信号里由振动引起的偏振态变化信息。立足于将基于偏振敏感光时域反射仪的全分布式振动传感器开发成一个便捷的测量仪器,研究了偏振敏感分布式振动光纤振动传感实验系统的数据处理与分析方法,重点研究了数字平均降噪和小波降噪以提高系统的响应实时性和信噪比。研究上述方法下系统的信噪比、响应时间、振幅分辨率、频率分辨率等参数所能达到的精度。研究结果表明使用时域波形平均的方法和小波降噪的方法均可大幅提高系统信噪比。系统实现了14 km的分布式振动传感,在1.26 s的时间响应下达到1 Hz的频率分辨率,系统信噪比达10 d B。     

Effects of P-N and N-N heterostructures and band alignment on the performance of low-temperature solid oxide fuel cells

Reducing the operating temperature of solid oxide fuel cells (SOFCs) has attracted worldwide attention in recent years. This has prompted massive efforts in developing new electrolyte materials for low-temperature SOFCs, typically including heterostructure materials consisting of semiconductors and ionic conductors. In this study, a p-n heterostructure (LiZnO–SnO₂) and an n-n heterostructure (ZnO–SnO₂) are proposed and evaluated in SOFCs to tap further the potential of a heterostructure for low-temperature electrolyte use. The results show that the developed LiZnO–SnO₂ and ZnO–SnO₂ both capably play competent electrolyte roles in SOFCs with high ionic conductivities and promising fuel cell performance, achieving peak power outputs of 376 and 255 mW cm^?2 at 530 °C, respectively. To interpret the good performance of the two heterostructure electrolytes, energy band alignment mechanisms based on p-n hetero-junction and n-n heterostructure are employed to illustrate the ionic enhancement and electronic suppression processes of the materials. These findings reveal new insight into developing heterostructure electrolytes for low-temperature SOFCs.     

Efficient visible light driven 2,4,6-triaminopyrimidine modified graphitic carbon nitride for hydrogen evolution

Carbon doping has been proven to be an effective method for extending the light trapping of graphite carbon nitrides and improving its charge separation and transport, while the specific location of their doping has received little attention. Herein, using 2,4,6-triaminopyrimidine as the precursor of doped carbon, a simple, green and template-free method is applied to prepare carbon doping graphitic carbon nitride by supramolecular self-assembly techniques. In this process, the three precursors could be closely linked by hydrogen bonds because of the structural similarity between 2,4,6-triaminopyrimidine and melamine. Spectral and electrochemical tests demonstrated that the best carbon-doped samples owned narrow band gaps, longer carrier life and low photoelectron-hole recombination rate. Meanwhile, its hydrogen evolution rate reached 299.05  μmol h^?1, almost 25.89 times than that of pristine carbon nitride. This work provided new opportunities for the precise control of the heteroatoms in the carbon nitride structure and the accurate adjustment of its inherent band-gap structure.     

Event-triggering Consensus for Second-order Leader-following Multiagent Systems with Nonlinear Time-delayed Dynamics

International Journal of Control, Automation and Systems - This work focuses on the leader-following consensus problem for networks of dynamic agents, each of which has second-order nonlinear...     

Stability considerations of semiconductor ionic fuel cells from a LNCA (LiNi0.8Co0.15Al0.05O2-δ) and Sm-doped ceria (SDC; Ce0.8Sm0.2O2-δ) composite electrolyte

Recent advances in composite materials, especially semiconductor materials incorporating ionic conductor materials, have led to significant improvements in the performance of low-temperature fuel cells. In this paper, we present a semiconductor LNCA (LiNi_0.8Co_0.15Al_0.05O_2-δ) which is often used as electrode material and ionic Sm-doped ceria (SDC; Ce_0.8Sm_0.2O_2-δ) composite electrolyte, sandwiched between LNCA thin-layer electrodes in a configuration of Ni-LNCA/SDC-LNCA/LNCA-Ni. The incorporation of the semiconductor LNCA into the SDC electrolyte with optimized weight ratios resulted in a significant power improvement, from 345 mW cm^?2 with a pure SDC electrolyte to 995 mW cm^?2 with the ionic-semiconductor SDC-LNCA one where the corresponding ionic conductivity reaches 0.255 S cm^?1 at 550 °C. Interestingly, the coexistence of ionic and electron conduction in the SDC-LNCA membrane displayed not any electronic short-circuiting but enhanced the device power outputs. This study demonstrates a new fuel cell working principle and simplifies technologies of applying functional ionic-semiconductor membranes and symmetrical electrodes to replace conventional electrolyte and electrochemical technologies for a new generation of fuel cells, different from the conventional complex anode, electrolyte, and cathode configuration.     

Effects of ultrasound power on the properties of non-salt chicken myofibrillar protein emulsions

The present study was designed to investigate the effects of different ultrasonic powers (0–600 W) on the storage stability, rheological properties and microstructure of non-salt chicken myofibrillar protein (MP) emulsions. The Turbiscan stability index (TSI) values, storage modulus (G′) values, loss modulus (G″) values, viscosity values and droplet size of the MP emulsions first increased and then decreased with an increase in ultrasonic power. The results of the creaming index and TSI values showed that ultrasonic treatment effectively improved the storage stability of the emulsions compared with non-ultrasonic treatment. Meanwhile, sonication decreased the oil droplet size and the contact angles accompanied by an increase in G′ and G″ values and the viscosity. The oil droplets became smaller and more uniform distribution observed through the different kinds of microscopic analysis. The physical stability of non-salt MP emulsions treated with different ultrasonic powers was significantly enhanced, and ultrasonic treatment with 450 W power had the optimal efficiency for the stability of the emulsions.     

Treatment with hydrogen peroxide improves the physicochemical properties of dietary fibres from Chinese yam peel

Yam is a common ‘medicine food homology’ vegetable in Asia, and its peel is often considered a food residue during processing or cooking. In this work, the effects of hydrogen peroxide modification on the dietary fibres (DFs) from Chinese yam peel (CYP) were investigated. The structural characteristics of soluble dietary fibre (SDF), insoluble dietary fibre (IDF), modified soluble dietary fibre (MSDF) and modified insoluble dietary fibre (MIDF) were analysed using Fourier-transform infrared spectroscopy, X-ray diffraction, differential scanning calorimetry, granularity analysis, scanning electron microscopy and GC-MS (monosaccharide composition). As results, after modification with hydrogen peroxide, the sizes of the DFs were reduced and MIDF exposed more cellulose. Experiments on the physicochemical and functional properties of DFs showed that MSDF and MIDF obtained a better water holding capacity, oil absorption capacity, swelling capacity and absorption abilities with altered structures, which is of great importance in food processing and development.