槐米提取物的抗氧化性能研究

采用Rancimat酸败仪研究了槐米提取物及其与增效剂协同作用的抗脂质氧化性能,结果表明:槐米提取物对猪油具有较强的抗氧化性能,与柠檬酸的协同抗氧化效应显著;采用DPPH法、水杨酸法研究了提取物对DPPH自由基、羟基自由基的清除效果,结果表明:槐米提取物具有较强的清除自由基的能力.     

QM基因研究进展

对QM基因的研究进展做了综述,希望为深入开展不同物种QM基因功能研究提供一些参考。     

链霉菌TD-1代谢产物对饲料中污染霉菌的抑制作用及稳定性

采用对峙培养法,检测分离于土壤中的链霉菌TD-1代谢产物对饲料中污染霉菌构巢曲霉（Aspergillus nidulans）、纯绿青霉（Penicillium verrucosum）、赭曲霉（Aspergillus ochraceus）、黄曲霉（Aspergillus flavus）、黑曲霉（Aspergillus niger）、米曲霉（Aspergillus oryzae）、茄腐镰刀菌（Fusarium solani）、桔青霉（Penicillum citrinum）、串珠镰刀菌（Fusarium moniliforme）的抑菌活性,结果表明：TD-1菌株代谢产物对以上霉菌具有较强的抑制作用,抑菌带宽度为10 mm左右.通过TD-1菌株的代谢过程曲线发现,该菌株发酵至第6 d抑菌率达90%左右.稳定性试验结果显示：该菌株所产生的活性物质具有较好的耐热性、耐酸碱性、抗紫外辐射能力.     

On a generalised plane strain crack problem for inhomogeneous anisotropic elastic materials

A generalised plane strain crack problem is considered for a class of inhomogeneous anisotropic elastic materials. The problem is reduced to a boundary integral equation involving hypersingular integrals. The boundary integral equation may be solved numerically using standard procedures. Some crack problems for a particular inhomogeneous material are considered in detail and the stress intensity factors are obtained in order to assess the effect of the anisotropy and inhomogeneity on the stress field near the crack tips.     

3种磷酸盐对冷藏牦牛肉中水分的调控作用

采用低场核磁共振(low-field nuclear magnetic resonance,LF-NMR)结合主成分分析,研究焦磷酸钠、六偏磷酸钠和三聚磷酸钠3种磷酸盐对牦牛肉冷(冻)藏过程中水分的调控作用。结果表明:牦牛肉经过4 ℃冷藏处理24 h,同时含有结合水和自由水;而经过-20和-70 ℃冷冻处理24 h后,结合水消失,且自由水含量显著减少(P＜0.05)。经3种磷酸盐分别腌渍24 h,其对牦牛肉的保水作用强度依次为:三聚磷酸钠>六偏磷酸钠>焦磷酸钠。当焦磷酸钠、三聚磷酸钠、六偏磷酸钠的质量分数分别在0.36%~0.41%、0.30%~0.45%和0.35%时,牦牛肉的保水性最佳。主成分分析结果进一步验证了磷酸盐对牦牛肉保水性存在显著影响,其中相对自由水峰面积RPA为主要影响指标。研究结果将为牦牛肉的贮藏保鲜技术提供科学依据。     

Fe<Subscript>3</Subscript>O<Subscript>4</Subscript>@PAM@NTA-Ni<Superscript>2+</Superscript> Magnetic Composite Nanoparticles for Highly Specific Separation of His-tagged Proteins

A facile approach has been developed to synthesize Fe₃O₄@PAM (polyacrylamide) nanoparticles (NPs) with carboxyl groups on the surfaces by copolymerization with acrylamide and acrylic acid in Fe₃O₄ NPs aqueous suspension. Nitrilotriacetic acid (NTA) was conjugated to the magnetic NPs via well-known carboniimide chemistry using EDC and NHS. The Ni²⁺ ions loaded on the surface of NPs provide abundant docking sites for immobilization of His-tagged green fluorescent proteins (His-tagged GFP). The high magnetic property of Fe₃O₄@PAM@NTA-Ni²⁺ allows an easy separation of the NPs from solution under an external magnetic field, with high His-tagged protein binding capacity (42 μg protein/mg of NPs). The NPs can be recycled for at least four times without significant loss of binding capacity to proteins. These materials show great potential to separate His-tagged protein with low-cost purification at industrial scale.     

不同蒸煮方式青蟹肌肉感官品质分析和比较研究

为研究热水上锅蒸(热蒸)、热水下锅煮(热煮)、冷水上锅蒸(冷蒸)和冷水下锅煮(冷煮)青蟹肌肉感官品质差异,对4种烹制方式下青蟹肌肉感官品质进行分析与比较.结果表明:冷蒸雄蟹和热蒸雌蟹肌肉的感官评价较好;利用游离氨基酸的味觉活度值进行滋味分析,发现肌肉整体滋味偏甜,甜味的主要来源为甘氨酸、丙氨酸和精氨酸,且冷蒸雄蟹肌肉和...     

4,4-二甲基甾醇生物活性研究进展

旨在为4,4-二甲基甾醇在功能食品、保健品和药品等领域的开发应用提供科学的理论参考,概述了4,4-二甲基甾醇的来源、提取与分离纯化方法、鉴定方法及吸收与代谢,在此基础上对4,4-二甲基甾醇的降血糖、抗炎、减肥降脂、抑菌、抗肿瘤及抗阿尔茨海默病等方面表现的潜在生物活性进行了归纳总结,并对目前存在的问题提出相应的对策。4,4-二甲基甾醇是一种重要的植物甾醇,具有多种生物活性,表现出较大的潜在应用价值。     

Performance of a high density projection chamber

The high density projection chamber (HPC) is a large volume gas sampling calorimeter. The highly granulated module allows a complete three-dimensional reconstruction of the shower and offers good energy resolution. We will present preliminary results from test runs and discuss operation in a magnetic field.