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关键词： lipid oxidation   malondialdehyde   4-hydroxy-nonenal   xCelligence   gamma-H2AX assay  

摘要： We studied the formation of malondialdehyde, 4-hydroxy-nonenal, and hexanal (lipid oxidation products, LOP) during in vitro digestion Of a cooked low-fat and high-fat beef product in response to the addition of reducing compounds. We also investigated whether higher LOP in the digests resulted in a higher cyto- and genotoxicity in Caco-2, HT-29 and HCT-116 cell lines. High-fat compared to low-fat beef digests contained approximately 10-fold higher LOP concentrations (all P < 0.001), and induced higher cytotoxicity (P < 0.001). During digestion of the high-fat product, phenolic acids (gallic, ferulic, chlorogenic, and caffeic acid) displayed either pro-oxidant or antioxidant behavior at lower and higher doses respectively, whereas ascorbic acid was pro-oxidant at all doses, and the lipophilic reducing compounds (alpha-tocopherol, quercetin, and silibinin) all exerted a clear antioxidant effect. During digestion of the low-fat product, the hydrophilic compounds and quercetin were antioxidant. Decreases or increases in LOP concentrations amounted to 100% change versus controls.

关键词： Glycoform   Glycoprotein species   N-glycosylation   Microheterogeneity   Protein species   Recombinant glycoprotein  

摘要： Glycosylation is the most complex post-translational modification. Thus, it contributes to versatile chemical compositions of proteins, leading to high amounts of protein species. The structural heterogeneity of glycoproteins was also described by the definition of glycoforms. We therefore introduced a new term called "glycoprotein species" to join the two concepts from different fields of biology. In this study, we further determined the theoretical numbers of glycoprotein species of two recombinant glycoproteins a therapeutical antibody and the human protease inhibitor alpha-1-antitrypsin (A1AT) - based on structural analysis of their N-glycans. Moreover, we showed that variations in the used cell lines and their cultivation conditions strongly influence the number of glycoprotein species in case of recombinant A1AT production. (C) 2015 Elsevier B.V. All rights reserved.

关键词： Amorphous magnetic wires   Magnetic domains   Magneto-optic Kerr effect  

摘要： The influence of temperature on surface magnetic structure has been studied in Co- and Fe-rich magnetic glass covered microwires. The investigations have been performed using magneto-optical Kerr effect technique with a thermo-controlled system. It was found different types of domain structures depending on the temperature and the microwire composition. These types are characterised by the different domain period and the angle of the inclination of domain walls. It was established the direct correlation between surface domain structures and hysteresis loops. The coexistence of domain walls with different value of mobility has been found. It was observed original mechanism of the domain structure transformation: sharp change in the domain structure without movement of the domain walls. (C) 2015 Elsevier B.V. All rights reserved.

关键词： Pb   Isotope ratios   Organic soil   Mineral soil   Scotland  

摘要： Some 644 individual soil horizons from 169 sites in Scotland were analyzed for Pb concentration and isotopic composition. There were three scenarios: (i) 36 sites where both top and bottom(i.e. lowest sampled) soil horizons were classified as organic in nature, (ii) 67 with an organic top but mineral bottom soil horizon, and (iii) 66 where both top and bottom soil horizons were mineral. Lead concentrations were greater in the top horizon relative to the bottom horizon in all but a few cases. The top horizon Pb-206/Pb-207 ratio was lesser (outside analytical error) than the corresponding bottom horizon Pb-206/Pb-207 ratio at (i) 64%, (ii) 94% and (iii) 73% of sites, and greater at only (i) 8%, (ii) 3% and (iii) 8% of sites. A plot of Pb-208/Pb-207 vs. Pb-208/Pb-206 ratios showed that the Pb in organic top (i, ii) and bottom (i) horizons was consistent with atmospherically deposited Pb of anthropogenic origin. The Pb-206/Pb-207 ratio of the organic top horizon in (ii) was unrelated to the Pb-206/Pb-207 ratio of the mineral bottom horizon as demonstrated by the geographical variation in the negative shift in the ratio, a result of differences in the mineral horizon values arising from the greater influence of radiogenic Pb in the north. In (iii), the lesser values of the Pb-206/Pb-207 ratio for the mineral top horizon relative to the mineral bottom horizon were consistent with the presence of anthropogenic Pb, in addition to indigenous Pb, in the former. Mean anthropogenic Pb inventories of 1.5 and 4.5 g m(-2) were obtained for the northern and southern halves of Scotland, respectively, consistent with long-range atmospheric transport of anthropogenic Pb (mean Pb-206/Pb-207 ratio similar to 1.16). For cultivated agricultural soils (Ap), this corresponded to about half of the total Pb inventory in the top 30 cm of the soil column. (C) 2015 Elsevier B.V. All rights reserved.

关键词： Deepwater Horizon spill   Deep-sea benthos   Sediment trap   Biomarkers   Gulf of Mexico   Biomass  

摘要： Deep-sea ecosystems encompass unique and often fragile communities that are sensitive to a variety of anthropogenic and natural impacts. After the 2010 Deepwater Horizon (DWH) oil spill, sampling efforts documented the acute impact of the spill on some deep-sea coral colonies. To investigate the impact of the DWH spill on quality and quantity of biomass delivered to the deep-sea, a suite of geochemical tracers (e.g., stable and radio-isotopes, lipid biomarkers, and compound-specific isotopes) was measured from monthly sediment trap samples deployed near a high-density deep-coral site in the Viosca Knoll area of the north-central Gulf of Mexico prior to (Oct-2008 to Sept-2009) and after the spill (Oct-10 to Sept-11). Marine (e.g., autochthonous) sources of organic matter (OM) dominated the sediment traps in both years, however after the spill, there was a pronounced reduction in marine-sourced OM, including a reduction in marine-sourced sterols and n-alkanes and a concomitant decrease in sediment trap organic carbon and pigment flux. Results from this study indicate a reduction in primary production and carbon export to the deep-sea in 2010-2011, at least 6-18 months after the spill started. Whereas satellite observations indicate an initial increase in phytoplankton biomass, results from this sediment trap study define a reduction in primary production and carbon export to the deep-sea community. In addition, a dilution from a low-C-14 carbon source (e.g., petro-carbon) was detected in the sediment trap samples after the spill, in conjunction with a change in the petrogenic composition. The data presented here fills a critical gap in our knowledge of biogeochemical processes and sub-acute impacts to the deep-sea that ensued after the 2010 DWH spill. Published by Elsevier Ltd.

关键词： 车辆   列车   阻力   线路坡度   标准   调速设备  

摘要： 根据车辆所受基本阻力、曲线阻力、坡道阻力、风阻力、道岔阻力,建立车辆单位基本阻力模型及数学表达式,运用车辆参数及风阻力参数,对车辆相关状态进行分析计算,研究表明:线路纵坡即使为平坡,亦存在溜逸安全隐患,必须采取措施才能保证安全;对《站规》站线纵坡标准,进行安全评估,提出利用停车顶改善车辆停放状态的措施意见及计算办法;利用减速顶做功耗能可以提高装车线线路纵坡,从而满足定量快速装车或轨道衡计量系统的技术要求,为线路纵坡设计提供依据,拓宽站场调速设备应用领域,创新工程设计方法,为工程综合优化设计提供理论基础,供设计分析及计算参考。

关键词： 高速列车   列车风   跨线天桥   列车风压力系数  

摘要： 采用计算流体力学软件Fluent和滑移网格技术,结合k-ε二方程湍流模型,对高速列车通过跨线天桥时作用在天桥表面的列车风压进行数值模拟,研究跨线天桥的高度和宽度对其表面列车风压的影响。结果表明:跨线天桥宽度对天桥表面列车风压的影响很小,而高度的影响显著,天桥表面列车风压随跨线天桥高度的升高呈指数降低,且列车运行速度越高天桥表面列车风压下降的速度越快,天桥高度由5m升至10m条件下,车头和车尾经过时天桥迎风面的列车正风压极值分别下降78%和80%,负风压极值分别下降88%和85%,负风压极值比正风压极值的衰减速度更快;天桥底面的列车风压变化规律与迎风面类似;不同列车运行速度下天桥表面列车风压力系数的变化规律基本一致,即列车运行速度不影响天桥表面的列车风压力系数,据此建议用不同高度跨线天桥表面的列车风压力系数与其到列车中心线水平距离的关系曲线对现行高速铁路设计规范进行补充。

关键词： 地铁地下车站结构   反应位移法   反应加速度法   非线性时程分析法   对比分析  

摘要： 以典型的两层三跨地铁地下车站结构为研究对象,采用基于自由场位移场频域等效线性分析结果的反应位移法和反应加速度法分析地下结构的地震弯矩,并与基于ABAQUS软件的地下结构地震反应非线性时程分析的计算结果进行了比较,对比了不同地震动强度、结构刚度及顶板埋深对地下结构地震弯矩的影响。结果表明:输入地震动强度越大,拟静力法与动力非线性时程法计算结果之间的差异越大;地下结构刚度越大,两者之间的差异也越大;中等强度的地震动作用时,相对于动力非线性时程法的计算结果,浅埋结构的拟静力法结果偏大,深埋结构的拟静力法计算结果偏小;反应位移法和反应加速度法的计算结果差异很小。该研究结果对地下结构抗震设计方法的比选具有一定的指导意义。

关键词： 晚霜冻   产量   穗粒数   冬小麦   特征空间  

摘要： 晚霜冻是一种突发性的低温农业气象灾害,在我国黄淮小麦区几乎每年都有不同程度的发生,对冬小麦的稳产影响巨大。针对商丘市2013年发生的冬小麦严重晚霜冻,利用MODIS大气廓线产品分析晚霜冻对冬小麦产量要素的影响,以探究晚霜冻对冬小麦产量要素的影响特征。在获取MYD07_L2产品中的表面温度ST和低空可降水量WVL的基础上,分析晚霜冻过程与温湿度时间序列的关系,结合受冻小麦的实测数据,构建温湿度特征空间,分析低温低湿对产量要素的影响特征。结果表明:ST和WVL可以很好地反映研究区冬小麦生长的气象环境条件,其极端低温日期与实际的晚霜冻发生日期匹配良好,能很好地反映晚霜冻发生时冬小麦的低温低湿状态;晚霜冻发生过程中温湿度对穗粒数有显著的影响,最低温对穗粒数的影响明显,0℃以下的低温也呈现显著的叠加效应,对穗粒数影响显著;低温和低湿的共同作用对穗粒数有明显影响,小于0℃低温叠加与极端最低温对穗粒数的显著影响相似,能反映晚霜冻对穗粒数的明显影响。研究结果可对冬小麦拔节后晚霜冻造成产量影响的早期预判提供依据。

关键词： 饱和土   衬砌结构   浮置板轨道   动力响应   移动简谐荷载  

摘要： 采用解析法研究了移动简谐荷载作用下饱和土全空间中圆形衬砌隧道和轨道结构的动力响应,用无限长圆柱壳模拟衬砌,用Biot饱和多孔介质理论模拟土体,用Euler梁理论模拟钢轨、浮置板并组成周期性的两层叠合梁单元,结合轨道与衬砌仰拱处的力和位移连续条件,实现轨道结构与衬砌及周围饱和土体的耦合。通过算例分析了荷载移动速度、自振频率对轨道结构位移、饱和土体位移及孔压的影响,对比了连续浮置板轨道和离散浮置板轨道的动力特性。结果表明:离散浮置板轨道情形下,轨道结构和饱和土体响应频谱中存在由荷载周期通过不连续浮置板而引发的参数激励;荷载自振频率接近轨道结构固有频率时产生共振,对轨道结构和饱和土位移、孔压响应均有较大影响;离散浮置板轨道和连续浮置板轨道动力特性有显著差异,当荷载频率接近有限长浮置板形成驻波的频率时,二者对应的自由场响应区别明显;增大衬砌厚度可以显著减小饱和土位移响应。