超高压处理对牡蛎中GII.4型诺如病毒的消减控制

诺如病毒（NoVs）是世界范围内引起非细菌性胃肠炎的主要病原体。为研究不同压力条件的超高压处理对牡蛎中NoVs消减控制的影响,将GⅡ.4型NoVs分别置于牡蛎消化腺匀浆和PBS缓冲液中,采用压力分别为200,300,400,500MPa,加压初始温度5℃,保压时间5 min进行处理,并以常压（0.1 MPa）处理为对照组。采用PMAxx-RT-qPCR与透射电子显微镜检测超高压处理后的NoVs,评价不同压力对牡蛎消化腺匀浆和PBS缓冲液中GⅡ.4型NoVs的消减效果;测定超高压处理后牡蛎丙二醛含量和蛋白质巯基含量,评价超高压处理对牡蛎中脂肪和蛋白质的影响。研究结果显示：PMAxx可有效区分感染性NoVs;qPCR检测发现经不同压力的超高压处理后,牡蛎消化腺匀浆和缓冲液中NoVs的RNA拷贝数均显著减少,当压力为500 MPa时,牡蛎和缓冲液中的RNA拷贝数减少量分别>3.49 lg(copies/μL)和>3.61 lg(copies/μL),均降至检测限以下;超高压处理对PBS缓冲液中NoVs的消减效果优于牡蛎消化腺匀浆,还可使牡蛎中脂肪氧化和蛋白质变性,然而,改变程度小...     

Preparation and optimisation of liposome‐in‐alginate beads containing oyster hydrolysate for sustained release

Oyster (Crassostrea gigas) hydrolysate shows antihypertensive effect in our previous study. Oral administration of oyster hydrolysate can loss bioactive peptides due to enzymatic degradation in vivo. To maximise its bioavailability, liposome‐in‐alginate (LA) beads were used to encapsulate the oyster hydrolysates to protect from degradation and obtain sustained release. The preparation conditions of the LA beads were optimised by response surface method using a model peptide of tyrosylalanine (YA). Their characterisation, swelling and release properties were investigated. The optimised conditions for the concentration of calcium chloride, sodium alginate and the amount of ethanol‐dissolved lecithin (EDL) were 0.5 m , 3% and 95.4 mg, respectively. The encapsulation efficiencies of YA and the oyster hydrolysate in the optimised condition were 74.9% and 84.3%, respectively. The release time of the oyster hydrolysate in the simulated gastrointestinal fluid was up to 16 h. The LA beads can be recommended to encapsulate oyster hydrolysate for bioavailability improvement.     

粉末冶金法制备SiC颗粒增强AZ81镁基复合材料性能研究

研究了粉末冶金法制备SiC颗粒增强AZ81镁基复合材料的力学性能及力学性能变化的机理。实验结果表明，与AZ81基体相比，通过加入一定合适体积的SiC颗粒，SiCp／AZ81复合材料的拉伸强度、断裂韧性、硬度均有了较大提高，其最大值分别达到271．61MPa，5．96MPa·m^1/2，2．52GPa。     

Antibacterial activity of shrimp chitosan against Escherichia coli

The effects of cell age, reaction temperature, pH value, and salts on the inhibitory activity of shrimp chitosan (98% deacetylated) against Escherichia coli were investigated. The age of a bacterial culture affected its susceptibility to chitosan, with cells in the late exponential phase being most sensitive to chitosan. Higher temperature (25 and 37 degrees C) and acidic pH increased the bactericidal effects of chitosan. Sodium ions (100 mM Na+) might complex with chitosan and accordingly reduce chitosan's activity against E. coli. Divalent cations at concentrations of 10 and 25 mM reduced the antibacterial activity of chitosan, in the order of Ba2+ > Ca2+ > Mg2+. Chitosan also caused leakage of glucose and lactate dehydrogenase from E. coli cells. These data support the hypothesis that the mechanism of chitosan antibacterial action involves a cross-linkage between the polycations of chitosan and the anions on the bacterial surface that changes the membrane permeability.     

Short communication: lack of stage-specific embryonic antigen-1 expression by bovine embryos and primordial germ cells

The objective of this study was to determine whether stage-specific embryonic antigen-1, a cellular marker commonly used to identify murine undifferentiated embryonic cells, is also a useful marker for bovine pluripotent cells. Expression of stage-specific embryonic antigen-1 was examined by indirect immunohistochemistry on bovine preimplantation embryos and on primordial germ cells contained in the genital ridge. Expression of stage-specific embryonic antigen-1 was not observed in any of the cleavage-stage bovine embryos examined, including one-cell, two-cell, four-cell, eight-cell, morula, and blastocyst stages, nor in tissue sections of bovine genital ridges collected from embryos on d 34, 37, and 40 of gestation. As expected, expression of stage-specific embryonic antigen-1 was detected on murine preimplantation embryos and on murine teratocarcinoma cells. Results of this study indicate that, unlike in the mouse, stage-specific embryonic antigen-1 is not a useful cellular marker for pluripotent bovine embryonic cells or bovine primordial germ cells.     

Two-stage Nested PCR Effectiveness for Direct Detection of Vibrio vulnificus in Natural Samples

The nested primers designed to amplify a 222-base pair portion of the hemolysin gene, vvhA, were specific for all V. vulnificus strains tested. The nested PCR amplification, coupled with direct extraction of template DNA, revealed improved sensitivity sufficient for detection of 1 to 10 CFU V. vulnificus in 1 mL of seafood homogenates, and eliminated the need for enrichment culturing. Thereby, the nested PCR method achieved a broader applicability, making it effective for extensive use in identification of the pathogen in natural samples such as raw seafoods, seawater and sediments.     

Structure and Composition of Mushrooms as Affected by Hydrogen Peroxide Wash

An experimental H₂O₂/browning inhibitor wash treatment and its effect on mushroom structure and composition were studied. Experimentally washed mushrooms ( Agaricus bisporus ) were compared with conventionally washed mushrooms and untreated controls. Examination by scanning electron microscopy showed damage to hyphae producing a matted appearance at the pileus surface with both experimental and conventional washed samples. Mushrooms after the experimental wash had an elevated sodium content from the sodium erythorbate browning inhibitor but contained no H₂O₂ residue. In pileus tissue, soluble phenol levels were higher and the content of free amino acids was lower in mushrooms after the experimental wash. No other notable compositional differences or adverse effects of treatment on quality were found.     

莲藕汁饮料的研制

本文对莲藕汁饮料研制过程中防褐变方法、酶法处理原汁等关键工艺、技术进行了研究,确定了科学的生产工艺、较好地解决了藕汁饮料生产过程中沉淀、褐变、涩味等突出问题,最大程度地保持了莲藕中原有的营养成份和药理功能。利用扬州地区白花莲藕研制出的天然莲藕汁饮料清雅爽口,藕香浓郁,风味独特,不含色素、香精和防腐剂。本产品为利用水生植物资源开发饮料食品开辟了新路。     

Verification of Authentication Protocols for Epistemic Goals via SAT Compilation

This paper introduces a new methodology for epistemic logic, to analyze communication protocols that uses knowledge structures, a specific form of Kripke semantics over hostile networks. The paper particularly focuses on automatic verification of authentication protocols. Our approach is based on the actual definitions of a protocol, not on some difficultto-establish justifications. The proposed methodology is different from many previous approaches to automatic verification of security protocols in that it is justification-oriented instead of falsification-oriented, i.e., finding bugs in a protocol. The main idea is based on observations： separating a principal executing a run of protocol from the role in the protocol, and inferring a principal＇s knowledge from the local observations of the principal. And we show analytically and empirically that this model can be easily reduced to Satisfiability （SAT） problem and efficiently implemented by a modern SAT solver.     

皮革手感的智能检测研究：Ⅱ人工神经网络在手感评定中的应用

人工神经网络具有较强的自适应模式识别能力和联想记忆能力。本文应用ＢＰ神经网络处理服装革的手感检测信号，为织物，皮革等服装材料的手感评定探索出一条新途径。