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83.
LIAO Wen-long LIU Kun-ping HU Jian-ping GAN Ya LIN Qing-yu DUAN Yi-xiang 《光谱学与光谱分析》2021,41(8):2372-2377
病原菌检测对于保障饮用水和食品安全,应对突发公共卫生事件至关重要。现行检测标准或方法存在操作耗时费力,成本高等缺陷,难以满足现代社会高时效性要求,因此开发操作简单、低成本的病原菌快检技术迫在眉睫。近年来,随着激光技术和光电探测技术的高速发展,能够快速获取微生物指纹信息的激光光谱引起了研究者的广泛关注,其中表面增强拉曼光谱(SERS)和激光诱导击穿光谱(LIBS)由于具有快速、原位无损或微损检测等优点,在病原菌快速检测领域广受关注。SERS作为一种分子振动光谱技术,是在常规拉曼(Raman)光谱中引入具有光学信号放大作用的贵金属纳米结构,实现Raman信号数量级的提升同时能够猝灭荧光,因此可以快速获取目标分子的指纹光谱信息。然而受贵金属纳米粒子的材质、形貌、大小等自身属性,以及与待测物距离等多种因素的影响,重现性仍然是SERS在细菌检测中的一大瓶颈。LIBS作为一种新兴的原子发射光谱技术,具有多元素实时检测的能力,可以快速获取样品包括微量和痕量元素在内的所有元素信息。LIBS进行细菌分类和鉴别时,为了降低基底、共存基质的元素干扰,需采集大量纯培养细菌的光谱数据,不仅增加了检测周期,同时带来定性定量难两全的局面。结合SERS和LIBS技术在病原菌快检领域的研究现状,综述了两类方法各自的优势和局限性,并对其在病原菌快速检测领域的发展趋势进行了展望,为开发基于激光光谱的病原菌快检技术提供参考意见。 相似文献
84.
Agnieszka Jankowska Aleksandra Grześkiewicz Krystyna Wiśniewska Arnold Reps 《高压研究》2013,33(3):339-346
Natural yoghurt was subject to pressures of 200 and 250 MPa/4 and 18°C/15 min, after which milk-activated inocula of Lactobacillus acidophilus and Bifidobacterium sp. were added. The yoghurts were stored for 4 weeks at refrigeration temperature. After preparation and each week of storage, the count of bacteria, acidity, antibacterial property and an organoleptic assessment was determined. The highest survival rate was demonstrated by the bacteria of Lactobacillus delbrueckii ssp. bulgaricus, Streptococcus thermophilus and Bifidobacterium sp. in the yoghurt pressurised 200 MPa/15min at 4°C. Acidity increases in the control yoghurts were higher than in the pressurised ones. Pressurised yoghurts demonstrated weaker antibacterial effect in comparison to control yoghurts. Slight changes in the smell and taste were observed after pressurisation. Yoghurts pressurised at 18°C were characterised by more favourable organoleptic properties. Better conciseness of the curd and lower whey seep out were observed in pressurised yoghurt. 相似文献
85.
鲍根德 《中国科学B辑(英文版)》1989,(11)
The concentration, source of manganese and iron in ferromanganese nodules and therelation between nodules and sedimentary environments are discussed in detail by asynthetical study on chemical information of ferromanganese nodules and correspondingsediment, pore water and geological, biological (bacteria) information in 26 stations fromthe North Pacific region (7- 13°N, 178- 165°W). The result shows that (i) the concen-tration and distribution characteristics of magnese and iron in ferromanganese nod-ules differ in different types of nodules, however, the concentration decreases with theincrease in grain sizes of nodules; (ii) the source of iron in different types of nodulesis basically the same, i. e. the slow sedimentation of overlying water; (iii) manganesein nodules comes mainly from the diffusion of Mn~(2+) in the pore water, and Mn~(2+) fromthe reduction of Mn~(4+) in sediments by the medium of bacteria. As the distribution of bac-teria is believed to be strongly affected by the sedimentary envi 相似文献
86.
A new pyridine-based diacid containing ether and imide units was synthesized via reaction of 5-amino-1-naphthol with 2,6-dichloropyridine in the presence of potassium carbonate in N-methyl-2-pyrrolidone (NMP), and subsequent reaction of the obtained diamine with 2 mol of trimellitic anhydride. A series of poly(ether imide ester)s was synthesized by the polycondensation reactions of the prepared diacid with different diols via high temperature solution polycondensation reaction method. All the products were fully characterized by common spectroscopic methods. The polymers were examined by elemental analysis, IR and 1H NMR spectra, inherent viscosity, X-ray diffraction, DSC, TGA and DMTA and their properties were studied. Polymers showed high thermal stability and good solubility in polar aprotic solvents. The Structure-property relations of the polymers were also studied. 相似文献
87.
O.A. Shilova S.V. Hashkovsky E.V. Tarasyuk V.V. Shilov V.V. Shevchenko Yu.P. Gomza N.S. Klimenko 《Journal of Sol-Gel Science and Technology》2003,26(1-3):1131-1135
The approach for improving bending strength of temperature-resistant flexible ceramic electric insulating coatings prepared by sol-gel processing is considered. Starting suspensions, based on both tetraethoxysilane (TEOS)-derived modified sols and highly dispersed fillers such as Cr2O3, are used to deposit the coatings on metals and alloys. Some polymers and organic substances are tested as additives for improving flexibility of the ceramic coatings. The results of study of both bending strength and electrical strength of flexible hybrid organic-inorganic insulation formed on a nichrome wire are discussed. The data obtained on the chemical and phase structure of the coatings, which have been heat treated at temperatures from 95 to 1100°C, using DSC as well as X-ray scattering techniques are presented. 相似文献
88.
89.
Summary A gas chromatographic method is presented which distinguishes phosphine from hydrogen sulfide and other possible headspace gases of anaerobic microbial cultures. In anaerobic cultures spiked with phosphine, this gas is recovered in the liquid and gaseous phase down to 10 pg per ml of gas or liquid. No biogenically produced phosphine was found. Phosphine in amounts as small as 30 ng per 1 can be stored for several days in glass bottles covered with rubber septa, filled with nitrogen, in the presence or absence of water or of an anaerobic bacterial culture. Due to the selectivity of the detector and the retention characteristics of the porous layer open tubular polymer column alkanes, alkenes and organosulfur compounds routinely found in anaerobic bacterial headspaces do not interfere with the analytical quantification of phosphine. 相似文献
90.
甲基营养细菌No1甲胺脱氢酶是以色氨酸-色氨酰醌为辅基的一种特殊氧化还原酶.粗酶液经纯化后,其比活力和收得率分别为5.1nmol·g-1和28%.该酶的分子量为67000,等电点为8.3和8.5,组成它的大、小两个亚基的分子量分别为37000和15000.甲胺脱氢酶有较好的耐热性,它能催化包括一级甲胺和二胺在内的底物反应,与甲胺反应的Km值为26.6μmol·L-1,最适pH为8.0.其酶催化反应可被Cu2+抑制.该酶的吸收光谱是,在328nm和426nm呈现两个特征峰 相似文献