分离用无机膜及其在食品中的应用

概述了无机膜的种类、特点,同时介绍了无机膜在食品分离中的研究应用情况及今后的发展前景。     

Applicability assessment of a real-time PCR assay for the specific detection of bovine,ovine and caprine material in feedstuffs

A TaqMan real-time polymerase chain reaction (PCR) method was developed for specific detection of bovine, ovine and caprine processed animal protein (PAP) in industrial feedstuffs. The method uses species-specific primers and probes targeting short mitochondrial D-loop sequences, and a positive amplification control based on 18S rRNA gene. The applicability of the real-time PCR protocol was assessed through analysis of 126 industrial feed samples that were manufactured to reproduce rendering processes of commercial feeds destined for farmed animals. The assay successfully classified samples as positive or negative according to the ruminant composition, enabling qualitative detection of banned material in feeds at levels as low as 0.1%. Although the method provides quantitative potential, results suggest that the real quantitative capability of the assay is limited by the existing variability in terms of composition and processing treatments of the feeds, which affect the amount and quality of amplifiable DNA.     

人工蜂群算法研究综述

人工蜂群算法是近年来群智能方向的研究热点.首先介绍了蜂群算法的思想,然后从Markov链角度证明了蜂群算法的收敛性,从算法改进和算法应用两个方面对蜂群算法的研究现状进行了总结,与其他算法进行了优缺点的对比,最后指出了蜂群算法进一步研究的方向.     

Effects of Quillaja saponaria extract and Nα-lauroyl-l-arginine ethyl ester on reducing selected foodborne pathogens in vitro and maintaining quality of fresh-cut endive (Cichorium endivia L.) at pilot plant scale

The aim of the present study was to evaluate the applicability of Quillaja saponaria extract (QSE) and N^α-lauroyl-l-arginine ethyl ester (LAE) as antimicrobial wash water additives in fresh-cut lettuce processing. Antibacterial activities of LAE and QSE against selected strains of the foodborne pathogens Salmonella enterica, Bacillus cereus, Staphylococcus aureus, Pseudomonas aeruginosa, and Listeria monocytogenes were examined in vitro. Minimum inhibitory concentrations determined by broth microdilution assay demonstrated that LAE exhibited a strong antimicrobial activity with MICs between 4 and 32 μg/mL against all tested strains, whereas QSE showed a weaker antimicrobial activity with MICs >512 μg/mL. On a pilot-plant scale, the effects of warm water washing at 45 °C for 120 s with and without 40 mg/L QSE or 100 mg/L LAE as well as cold water washing at 4 °C for 120 s with QSE or LAE, respectively, of shredded endive (Cichorium endivia L.) were investigated regarding microbiological and sensory quality as well as physiological properties. Samples were analyzed for headspace O₂ and CO₂ levels, phenylalanine-ammonia-lyase activity and contents of nitrite and nitrate during nine days of cold storage at 4 °C. By analogy to its antimicrobial effect against the foodborne pathogens in vitro, LAE allowed up to 4 log₁₀ cfu/mL reduction of the microbial load in the washing water of the pilot plant, and might therefore reduce cross-contamination while saving water. The addition of LAE to warm washing water impaired sensory properties of fresh-cut endive during storage, which was predicted by chlorophyll fluorescence imaging analyses. QSE treatment combined with warm water washing best retained sensory appearance throughout our study, being possibly suitable for the production of premium products.     

Multifunctional π-conjugated poly (3-methylthiophene) nanotubes for optoelectronic and field emissive devices

Multifunctional properties of nanomaterials becomes a hot topic in nano research for the development of multifunctional devices, because modern devices need multifunctional platform for the high efficient plural performance on a single device. Here, we introduce a multifunctional π-conjugated poly (3-methylthiophene) (P3MT) nanotube (NT), showing controllable optical and electrical properties through the control of doping level. P3MT NTs were electrochemically synthesized in the low temperature (−40 °C) on the nanoporous template. The change of doping level by post cyclic voltammetry (CV) treatment on the P3MT lead the variance of polaron/bipolaron band, resulting into the drastic change of ultraviolet-visible absorption and photoluminescence properties. While P3MT NTs before CV treatment show an ohmic behavior in the current-voltage characteristics, those after CV treatment show high photocurrent. From the field emission experiment, the P3MT NTs before CV treatment have a relatively low turn-on electric field and stable electron emission property compared to the P3MT NTs after CV treatment. This shows that the π-conjugated polymers should be shed new light on their multifunctionality for the potential application to the multifunctional platform of opto-electronic nanodevices.     

A Kernel PCA Shape Prior and Edge Based MRF Image Segmentation

We introduce both shape prior and edge information to Markov random field (MRF) to segment target of interest in images.Kernel Principal component analysis (PCA) is performed on a set of training shapes to obtain statistical shape representation.Edges are extracted directly from images.Both of them are added to the MRF energy function and the integrated energy function is minimized by graph cuts.An alignment procedure is presented to deal with variations between the target object and shape templates.Edge information makes the influence of inaccurate shape alignment not too severe,and brings result smoother.The experiments indicate that shape and edge play important roles for complete and robust foreground segmentation.     

基于小波变换理论的电磁泄漏信号处理方法

在电磁泄漏信号检测的过程中,由于外部噪声和检测系统内部产生的噪声,使原始信号中含有了大量的电磁噪声,给信号检测和提取带来了困难,尤其是一些微弱信号,它们很容易混叠在噪声中,而导致检测错误。因此,对所获取到的原始信号进行噪声消除,是我们首先要完成的工作。该文针对上述问题提出小波变换理论来消除电磁泄漏信号的噪声,并通过具体...     

浅谈光盘保护中应注意的问题

目前,光盘作为一种广泛使用的存储介质,已成为信息存储的主要载体。然而,由于光盘组成材料成分的复杂性,光盘的寿命受外界因素的影响较大。本文从光盘的结构及其组成材料入手,分析了影响光盘寿命的主要因素,并且探讨了光盘在日常的保存和使用过程中,应注意的问题。     

响应面法优化沙苑子中黄酮类化合物超声辅助提取工艺

为了获得沙苑子黄酮类化合物的最佳提取工艺参数,选取液料比、超声温度、沙苑子粒度、超声时间作为实验因素,以提取物的吸光度为响应值,采用响应面实验设计法对工艺参数进行优化。结果表明：沙苑子黄酮类丙酮提取物在323nm处有最大吸光值;60%丙酮为最佳提取剂;最佳工艺参数为粒度120目,超声温度50℃,超声时间60min,液料比40：1（mL/g）,粗提率为16.19%。环境扫描电镜显示,超声处理后沙苑子粉的表面出现了蜂窝状形貌图,从而促使胞内物质溶出,提高了提取率。