Method extension study to validate applicability of AOAC Official Method 996.14 Assurance polyclonal enzyme immunoassay for detection of Listeria monocytogenes and related Listeria spp. from environmental surfaces: collaborative study

Test portions from 3 environmental surface types, representative of typical surfaces found in a food production facility, were analyzed by the Assurance Listeria Polyclonal Enzyme Immunoassay (EIA) and the U.S. Department of Agriculture/Food Safety and Inspection Service (USDA/FSIS) culture method for Listeria monocytogenes and related Listeria species. In all cases, naturally contaminated environmental test samples were collected from an actual food production facility by sponge or swab. Test samples from concrete surfaces were collected by both swab and sponge; sponge test samples were collected from rubber surfaces, and swabs were used to sample steel surfaces. Test portions from each surface type were simultaneously analyzed by both methods. A total of 23 collaborators, representing government agencies, as well as private industry in both the United States and Canada, participated in the study. During this study, a total of 550 test portions and controls was analyzed and confirmed, of which 207 were positive and 336 were negative by both methods. Six test portions were positive by culture, but negative by the EIA. Three test portions were negative by culture, but positive by the EIA. Two test portions were negative by EIA and by culture, but confirmed positive when EIA enrichment broths were subcultured to selective agars. The data reported here indicate that the Assurance Listeria EIA method and the USDA/FSIS culture method are statistically equivalent for detection of L. monocytogenes and related Listeria species from environmental surfaces taken by sponges or swabs.     

Method extension study to validate applicability of AOAC Official Method 997.03 visual immunoprecipitate assay (VIP) for Listeria monocytogenes and related Listeria spp. from environmental surfaces: collaborative study

Test portions from 3 environmental surface types, representative of typical surfaces found in a food production facility, were analyzed by the Visual Immunoprecipitate assay (VIP) and the U.S. Department of Agriculture/Food Safety and Inspection Service (USDA/FSIS) culture method for Listeria monocytogenes and related Listeria species. In all cases, naturally contaminated environmental test samples were collected from an actual food production facility by sponge or swab. Test samples from concrete surfaces were collected by both swab and sponge; sponge test samples were collected from rubber surfaces, and swabs were used to sample steel surfaces. Test portions from each surface type were simultaneously analyzed by both methods. A total of 27 laboratories, representing government agencies as well as private industry in both the United States and Canada, participated in the study. During this study, a total of 615 test portions and controls was analyzed and confirmed, of which 227 were positive and 378 were negative by both methods. Nine test portions were positive by culture, but negative by the VIP. Five test portions were negative by culture, but positive by the VIP. Four test portions were negative by VIP and by culture, but confirmed positive when VIP enrichment broths were subcultured to selective agars. The data reported here indicate that the VIP method and the USDA/FSIS culture method are statistically equivalent for detection of L. monocytogenes and related Listeria species from environmental surfaces taken by sponges or swabs.     

Synthesis, properties, and applications of urethane-modified acrylated poly(ester-amide)s

Epoxy resin-based unsaturated poly(ester-amide) resins (UPEAs) were treated with acryloyl chloride to afford acrylated UPEAs resins (AUPEAs). Urethane-based acrylated poly(ester-amide)s prepared by reaction with diisocyanate were characterized by elemental analysis, by molecular weight determination (by vapour pressure osmometry), by IR spectral study, and by thermogravimetry. The curing of interacting blends was monitored by differential scanning calorimetry (DSC). On the basis of DSC data in-situ glass-reinforced composites were prepared from the resulting materials and their mechanical, electrical, and chemical properties were characterized. Unreinforced blends were characterized by thermogravimetry.     

Preparation and properties of polyurethane networks based on α,ω-difunctional poly(hexafluoropropylene oxide)

Poly(hexafluoropropylene oxide), poly(HFPO), networks were prepared from functional polymers by end linking via urethane groups. The prepolymers were characterized by NMR spectroscopy and GPC. The networks were characterized by determination of the number of network chains from the shear modulus, and were snown to contain both trifunctional crosslinks and difunctional links. The properties of the networks were investigated by a range of techniques. Compared with fully-fluorinated networks formed via triazine cross-links, investigated previously, the urethane-linked networks were more readily prepared but were poorer elastomers, were less thermally stable, and were less resistant to swelling by common polar solvents. © 1995 John Wiley & Sons, Inc.     

Kinetics and thermodynamics of the adsorption of some dyestuffs and p-nitrophenol by chitosan and MCM-chitosan from aqueous solution

The effect of initial concentration, temperature, and shaking rate on the adsorption of three dyestuffs [orange II (O-II), crystal violet (CV), and reactive blue 5 (RB5)] and an ideal adsorbate, p-nitrophenol (PNP), by chitosan (Sigma C-3646) and the effect of temperature on the adsorption of O-II and CV by monocarboxymethylated chitosan (MCM-chitosan) were investigated. Kinetic data obtained for the adsorption of each dyestuff and PNP by chitosan and of O-II and CV by MCM-chitosan at different temperatures were applied to the Lagergren equation, and adsorption rate constants (k(ads)) at these temperatures were determined. These rate constants related to the adsorption of O-II and RB5 by chitosan and of O-II by MCM-chitosan were applied to the Arrhenius equation, and activation energies (E(a)) were determined. In addition, the isotherms for adsorption, at different temperatures, of each dyestuff and PNP by chitosan and of O-II and CV by MCM-chitosan were also determined. These isothermal data were applied to linear forms of isotherm equations that they fit, and isotherm constants were calculated. Because the isotherm curves obtained for the adsorption of O-II and CV by chitosan and of CV by MCM-chitosan fit the Langmuir adsorption isotherm, b constants were applied to thermodynamic equations, and thermodynamic parameters (delta G, delta H, and delta S) were calculated. Lastly, chitosan and MCM-chitosan were compared with respect to the ability to take up the dyestuffs and PNP.     

系列甘露糖醛酸寡糖的制备与鉴定

用酸降解法制备了系列甘露糖醛酸寡糖(聚合度2～8),并分析测定了寡糖的结构. 褐藻胶经部分酸水解,于pH=2.85处分级获得聚甘露糖醛酸. 继续用酸降解法降解聚甘露糖醛酸,经凝胶柱层析分离纯化,获得系列甘露糖醛酸寡糖. 用荧光标记糖电泳(FACE)对寡糖进行了分析,并用电喷雾离子化质谱(ESI-MS)、 核磁共振波谱(NMR)及红外光谱(FTIR)进行了结构表征. 本研究用酸降解法制备饱和甘露糖醛酸寡糖,用凝胶柱层析法分离获得系列聚合度的寡糖,为褐藻胶大分子构效关系研究和药物的筛选与发现提供了重要的基础资料.     

对、间位卤代苯甲酸在水-乙醇混合溶剂中电离过程的焓、熵贡献

用LKB-2277Bioactivity Monitor测定了25℃时间氯、对氯和对氟苯甲酸在水-乙醇混合溶剂中的标准电离焓, 计算了相应体系的标准电离熵。利用Hammett方程对溶剂中酸的取代基常数σ进行了计算, 求取了对应的焓、熵取代基常数σH和σS值及熵反应常数ρS, 利用内部-环境模型和上述常数对溶剂效应和取代基效应进行了解释。     

污泥中常规生物指标的检测

介绍了污泥中三种常规生物检测指标,即细菌总数、粪大肠菌群和蛔虫卵的检测方法。污泥中细菌总数的检测采用平皿计数法,先将污泥样品稀释后选取2~3个适宜的稀释度进行培养;污泥中粪大肠菌群的检测采用多管发酵法,分别将稀释后的污泥混悬液接种于乳糖蛋白胨培养基和EC培养液中进行初发酵和复发酵实验;污泥中蛔虫卵的检测采用漂浮法,利用饱和硝酸钠溶液的比重大于蛔虫卵的原理,通过分离、离心、洗涤等步骤将样品中的蛔虫卵集中于载物玻片上镜检计数。文章对污水处理厂检测及排放污泥有一定的指导意义。     

Photophysical,Electrochemical, Thermal and Morphological Properties of Polyurethanes Containing Azomethine Bonding

In this paper, three new low band gap Schiff bases were prepared by using 3-etoxy-4-hydroxybenzaldehyde and different o-phylene diamines. Then, these Schiff bases were converted to low band gap polyurethane derivatives, and their photophysical, electrochemical, thermal, mechanical and morphological properties were investigated. Photophysical properties of the compounds were investigated by using UV-Vis and photoluminescence (PL) spectroscopy. Electrochemical properties of Schiff bases and polyurethanes containing azomethine were investigated by using cyclic voltammetry (CV). Thermal decomposition and transitions were determined by using TG-DTA, DMA and DSC techniques, respectively. Morphological properties of the compounds were also determined by using scanning electron microscopy (SEM). SEM images showed that polyurethanes containing azomethine consist of semi-crystalline particles.     

电感耦合等离子体原子发射光谱法(ICP-AES)测定铜磁铁矿中铜、锰、铝、钙、镁、钛和磷的含量

通过样品处理、干扰实验、方法检出限、准确度和精密度实验,确定了最佳实验条件,建立了电感耦合等离子体-原子发射光谱法(ICP-AES)测定铜磁铁矿中铜、锰、铝、钙、镁、钛和磷含量的方法。试料经盐酸、硝酸、氢氟酸、高氯酸分解,用盐酸溶解盐类,过滤,采用电感耦合等离子体原子发射光谱法同时测定滤液中铜、锰、铝、钙、镁、钛和磷的含量。方法检出限为锰、钛和磷小于0.00085%,其它元素小于0.0054%,分析结果与分光光度法、X射线荧光光谱法(XRF)和原子吸收光谱法(AAS)分析结果一致,8个实验室对5个水平样品进行协同实验给出了方法的精密度。     

基于不同提取方法的水稻叶片蛋白质组的二维液相色谱分离及高分辨质谱分析

建立了酚法提取-二维液相色谱分离-高分辨质谱分析水稻叶片蛋白质组的方法。水稻叶片蛋白质经过酚法提取,酶解肽段脱盐后用离线反相-反相二维液相色谱分离,然后用线性离子阱/静电场轨道阱组合式高分辨质谱分析,共鉴定到2712种蛋白质。比较了液相色谱分离系统（一维液相色谱与二维液相色谱）和水稻叶片蛋白质提取方法（酚法、十二烷基硫酸钠法（SDS法）和三氯乙酸/丙酮法（TCA/丙酮法））对鉴定蛋白质数量的影响,结果表明：在二维液相色谱条件下,酚法、SDS法和TCA/丙酮法鉴定到的蛋白质数目为2712、2415和1914,分别是一维液相色谱条件下鉴定到的蛋白质数目的2.7、2.5和1.9倍。二维液相色谱条件下,酚法鉴定到的蛋白质数目比SDS法和TCA/丙酮法分别多297和798。与SDS法和TCA/丙酮法相比,酚法不但鉴定到的蛋白质数量多,而且能够鉴定到一些极端蛋白质,如酸性、碱性及高等电点的蛋白质。此外,对二维液相色谱条件下3种蛋白质提取方法提取到的蛋白质进行生物学功能分类,发现3种方法鉴定到的蛋白质的功能存在互补性,但酚法鉴定到的蛋白质功能种类最多。该法为水稻蛋白质组学研究提供了技术支撑,同时也为其他作物的蛋白质组学研究技术提供重要的借鉴。     

Evaluation of the BAX system for detection of Salmonella in selected foods: collaborative study

A multilaboratory study was conducted to compare the automated BAX System to the standard cultural methods for detection of Salmonella in selected foods. Five food types--frankfurters, raw ground beef, mozzarella cheese, raw frozen tilapia fish, and orange juice--at 3 inoculation levels, were analyzed by each method. A sixth food type, raw ground chicken, was tested using 3 naturally contaminated lots. A total of 16 laboratories representing government and industry participated. In this study, 1386 samples were analyzed, of which 1188 were paired samples and 198 were unpaired samples. Of the 1188 paired samples, 461 were positive by both methods and 404 were negative by both methods. Thirty-seven samples were positive by the BAX System but negative by the standard reference method, and 11 samples were positive by standard cultural method and negative by the BAX System. Of the 198 unpaired samples, 106 were positive by the BAX System and 60 were positive by the standard cultural method. A Chi square analysis of each of the 6 food types, at the 3 inoculation levels tested, was performed. For all foods, the BAX System demonstrated results comparable to those of the standard reference methods based on the Chi square results.     

Preparation and Characterization of Nano-Structured SiO2 Thin Films on Carbon Steel

Nano-structured SiO2 thin films were prepared on the surface of carbon steel for the first time by LPD. The compositions of the films were analyzed by XPS, and the surface morphology of the thin films were observed by AFM. The thin films were constituted by compact particles of SiO2, and there was no Fe in the films. In the process of film forming, the SiO2 colloid particles were deposited or absorbed directly onto the surface of carbon steel substrates that were activated by acid solution containing inhibitor, and corrosion of the substrates was avoided. The nano-structured SiO2 thin films that were prepared had excellent protective efficiency to the carbon.     

CO2加氢合成二甲醚的催化剂的制备

先采用均匀沉淀法制备出CuO—ZnO催化剂,然后以CuO—ZnO催化剂作为晶核采用水热合成法制备出CuO—ZnO／HZSM-5（氢型ZSM-5分子筛）复合催化剂．利用X射线衍射和氨程序升温脱附手段对复合催化剂进行表征,并应用于CO2催化加氢合成二甲醚的反应．研究结果表明,在相同的反应条件下,这种CuO—ZnO／HZSM-5复合催化剂与采用物理混合法制备出的复合催化剂相比具有更好的催化效果,不但提高了CO2的转化率、二甲醚的选择性以及二甲醚和甲醇的总选择性,同时还改善了催化剂的稳定性．     

Amino acids and peptides. LV. Application of 2-adamantyl derivatives as protecting groups to the synthesis of peptide fragments related to Sulfolobus solifataricus ribonuclease. II.

Segment condensations were performed to construct peptide fragments related to Sulfolobus solifataricus Ribonuclease. At each condensation step, the new protecting groups were stable. The protected peptide fragments were treated with a low-high HF procedure to give the desired peptide fragments. These peptide fragments were also prepared by the solid-phase method, and the obtained peptides were compared with those obtained by the solution method. The peptide fragments obtained by the solution method were identical with those obtained by the solid-phase method on analytical HPLC, indicating that the new protecting groups could be easily removed by HF, and no racemization occurred during the synthesis of the protected peptides.     

蒸馏-萃取法与溶剂萃取法提取杏果实香气成分的比较

采用水蒸气蒸馏一萃取法和溶剂萃取法提取杏果香成分,用气相色谱一质谱联用测定其化学成分和质量分数,并对两种提取方法进行了比较。水蒸气蒸馏一萃取法提取的杏果香成分是74种,占总峰面积的73．604％;溶剂萃取法提取的杏果香成分是32种,占总峰面积的44．677％,两者相同的成分有21种。溶剂萃取法提取的主要是烷烃类化合物,水蒸气蒸馏萃取法提取的主要化合物为G醛类、C6醇类、内酯类、萜烯醇类、酮类、烷烃类等。结果表明：水蒸气蒸馏-萃取法能较好地提取杏果实香气成分。     

Fermented Oyster Extract Attenuated Dexamethasone-Induced Muscle Atrophy by Decreasing Oxidative Stress

It is well known that oxidative stress induces muscle atrophy, which decreases with the activation of Nrf2/HO-1. Fermented oyster extracts (FO), rich in γ-aminobutyric acid (GABA) and lactate, have shown antioxidative effects. We evaluated whether FO decreased oxidative stress by upregulating Nrf2/HO-1 and whether it decreased NF-κB, leading to decreased IL-6 and TNF-α. Decreased oxidative stress led to the downregulation of Cbl-b ubiquitin ligase, which increased IGF-1 and decreased FoxO3, atrogin1, and Murf1, and eventually decreased muscle atrophy in dexamethasone (Dexa)-induced muscle atrophy animal model. For four weeks, mice were orally administered with FO, GABA, lactate, or GABA+Lactate, and then Dexa was subcutaneously injected for ten days. During Dexa injection period, FO, GABA, lactate, or GABA+Lactate were also administered, and grip strength test and muscle harvesting were performed on the day of the last Dexa injection. We compared the attenuation effect of FO with GABA, lactate, and GABA+lactate treatment. Nrf2 and HO-1 expressions were increased by Dexa but decreased by FO; SOD activity and glutathione levels were decreased by Dexa but increased by FO; NADPH oxidase activity was increased by Dexa but decreased by FO; NF-κB, IL-6, and TNF-α activities were increased by Dexa were decreased by FO; Cbl-b expression was increased by Dexa but restored by FO; IGF-1 expression was decreased by Dexa but increased by FO; FoxO3, Atrogin-1, and MuRF1 expressions were increased by Dexa but decreased by FO. The gastrocnemius thickness and weight were decreased by Dexa but increased by FO. The cross-sectional area of muscle fiber and grip strength were decreased by Dexa but increased by FO. In conclusion, FO decreased Dexa-induced oxidative stress through the upregulation of Nrf2/HO-1. Decreased oxidative stress led to decreased Cbl-b, FoxO3, atrogin1, and MuRF1, which attenuated muscle atrophy.     

苯丙烯类葡萄糖氧苷的合成及其抗缺氧活性

以取代苯甲醛(1a~1t)为原料,通过Knoevenagel缩合、酯化和LiAlH₄还原等反应制得苯丙烯醇衍生物(3a~3t);以取代肉桂醛(1u~1x)为原料,经NaBH₄还原制得苯丙烯醇衍生物(3u~3x); 3a~3x与全乙酰化溴代葡萄糖经Koenigs-Knorr偶联反应及MeONa/MeOH体系脱除乙酰保护基反应,合成了24个苯丙烯类葡萄糖氧苷(5a~5x),其中5c,5f ~ 5x为新化合物,其结构经¹H NMR和ESI-MS表征。采用MTT法测定了5对缺氧损伤的内皮细胞(EA.hy926)的抗缺氧活性。实验结果表明： 5b, 5e, 5g, 5p, 5q, 5s, 5t和5y对EA.hy926的抗缺氧活性均高于经景天苷。     

新型取代苯甲胺葡萄糖氮苷的合成及其抗缺氧活性

以取代苯甲醛(1a~1s)为原料,通过三条路线［A:1a~1o为起始原料,经硼氢化钠还原和溴代反应制得苄基溴衍生物(3a~3o); 3a~3f与邻苯丁二酰亚胺经Gabriel反应制得N-苯甲基邻苯丁二酰亚胺衍生物(4a~4f); 4a~4f与水合肼反应后与D-吡喃葡萄糖反应合成了N-β-D吡喃葡萄糖苯甲胺类化合物(6a~6f)。 B: 3g~3o与全乙酰化D-吡喃葡萄糖胺反应制得全乙酰化葡萄糖氮苷5g~5o; 5g~5o在MeONa-MeOH中脱除乙酰基合成了6g~6o。 C: 1p~1s与全乙酰化D-吡喃葡萄糖胺反应制得全乙酰化葡萄糖氮苷5p~5s; 5p~5s经MeONa-MeOH脱除乙酰基合成了6p~6s］合成了19个取代苯甲胺N-β-D吡喃葡萄糖氮苷类似物(6a~6s,其中6a, 6b, 6e, 6f, 6j, 6n~6q, 6s为新化合物),其结构经¹H NMR和ESI-MS表征。采用MTT法研究了6a~6s对缺氧内皮细胞代谢活力的影响。结果表明： 6a, 6g, 6h和6l的抗缺氧活性优于红景天苷。     

锂离子电池纳米N iO负极材料的研究

分别应用溶胶凝胶法和室温固相法合成纳米N iO材料,运用DSC、TG等热分析技术分析了合成的样品,通过选择不同的溶剂和调节溶液的pH值,优化溶胶凝胶法合成纳米N iO负极材料.XRD、TEM技术表征材料的结构和形貌,并对所得材料作了电化学性能测试.