Comparison of phenolic profiles and antioxidant activities in skins and pulps of eleven grape cultivars(Vitis vinifera L.)

Eleven grape cultivars were analysed to explore the variety differences of fresh grape phenolic profiles. The results showed that free phenolics were predominant in grape skins and pulps, and showed the higher antioxidant activities than bound. In 11 cultivars, Muscat Kyoho extracts had the highest total phenolic content in skins(10.525 mg GAE g~(–1) FW) and pulps(1.134 mg GAE g~(–1) FW), and exhibited the highest DPPH radical scavening capacity(EC_(50)=11.7 μg mL~(–1)) and oxygen radical absorbance capacity(ORAC) value(190.57 μmol TE g~(–1) FW) of free phenolic in skin. In addition, the most abundant phenolics in grape skins were found to be flavonoids such as kaempferol in Kyoho skin(541.2 μg g~(–1) FW), rutin, catechin and epicatechin in Muscat Kyoho skin(262.3, 86.3 and 70.0 μg g~(–1) FW, respectively). Furthermore, the principal component analysis showed a strong difference of phenolic profiles with the cultivars, existing forms and distributions. Pearson correlation coefficient analysis showed a significant linear correlation between total phenolic content and antioxidant activity(P0.05). Therefore, both skins and pulps were rich sources of bioactive phenolic compounds, and Muscat Kyoho was the ideal source among all samples.     

基于Web of Science的五味子研究态势分析

基于Web of Science数据库,采用文献计量学方法,分析了2001—2014年10月10日全球发表的关于五味子研究的文献类型,年度发文量,居世界前10名的国家、机构、期刊和研究方向等情况。结果表明:2001—2014年10月10日全球发表的五味子文献共695篇,文献类型以学术论文为主;论文的产出量呈逐年上升趋势,2013年发文量最高,约是2001年的9倍;中国、韩国和美国发文量居世界前3位,中国发文量最多,为453篇;中国科学院和中国医学科学院论文数量多;最有学术影响力的发文期刊是《Organic Letters》,化学、药物药理及植物科学是五味子研究的重点领域。     

冻土帷幕界面设置加热限位管时温度场数值分析

为解决现有人工冻结法施工后周围地层产生冻胀融沉所引发不良后果的问题,可设置加热限位管对冻土帷幕的发展进行限制,从而达到控制冻胀融沉的目的。本文运用有限元软件研究在冻土帷幕界面上设置加热限位管时对冻土帷幕温度场发展的影响规律,主要得出:加热限位管盐水温度每升高5℃,冻土帷幕厚度就减小约0.2 m;在已冻结30 d,冻土厚度发展到1.6 m冻土上,加热限位管循环5℃盐水时,随着时间的增加冻土厚度慢慢变小,加热限位管作用效果明显;在限位管开始循环热水前期,各点温度都有明显上升,离限位管越近温度所受影响越大;随着时间的推移,各点温度趋于稳定,循环热盐水温度越高,趋于稳定的温度值也越高。所得结果可为今后类似工程设计提供参考依据。     

北京地区文献采购中招投标机制探究

招投标作为一种公开、公平、公正和竞争择优的市场交易方式,在当今社会经济活动中扮演着越来越重要的角色。论述了招投标机制的形成,图书馆文献采购中的招投标;研究分析了影响文献采购招投标工作的因素及对策;介绍了北京市评标专家库的建立。     

ABA、H_2O_2与NO供体硝普钠对基因表达以及枣果发育的影响

枣在成熟期间遇到连阴雨天气会发生严重的裂果现象,这种基于基因表达的生理病害的发生与非生物或生物胁迫有关。以吕梁当地木枣为试材,在木枣成熟期,采用改良CTAB法检测组织中DNA纯度及含量的变化,研究ABA、H2O2与NO供体硝普钠(SNP)在枣果发育中对基因表达的影响。结果表明:ABA、H2O2与NO供体硝普纳(SNP)对枣果发育中DNA纯度及含量的影响不一,差异较为明显。其中不同浓度的ABA处理枣果组织中DNA的OD260/OD280比值基本不在1.700~1.900范围内,DNA纯度差异明显。但样品DNA含量较高,其值在1 200ng/μL左右;H2O2和SNP处理样品DNA的OD260/OD280比值基本上在1.700~1.900之间,DNA纯度较高。样品DNA含量基本上小于或在1 000ng/μL左右。外源ABA较为明显地干扰了基因表达,诱导了新蛋白质、RNA和酚类物质等的生物合成,有促进木枣果发育的趋势;而H2O2和NO供体硝普钠(SNP)对基因表达或枣果发育的影响不十分明显。     

水肥一体化中水肥混合效果数值模拟研究

为研究水肥一体化技术中的水肥混合特性,以流体力学中的两相流理论为基础,针对水肥混合过程中混合时间、混合区间长度、流速及管径对其混合效果的影响进行相应的数值模拟研究。结果表明,混合时间及混合区间长度越长有利于提高水肥混合效果及最终水肥混合均匀性;水肥流速比较低时管内水肥混合的均匀性较好,且水肥流速越大则其混合效果及均匀性越好;水肥流速较低时输水管及输肥管的管径比对水肥混合均匀性的影响较大,两者管径比越小则混合效果越好,随着流速的提高两者管径比对其混合效果的影响逐渐减弱。     

Impact of fluxapyroxad on the microbial community structure and functional diversity in the silty-loam soil

The aim of this work was to assess the effect of applying three different doses of fluxapyroxad on microbial activity, community structure and functional diversity as measured by respiration, microbial biomass C, phospholipid fatty acid(PLFA) and community-level physiological profiles(CLPPs). Our results demonstrated that substrate-induced respiration(on day 15) and microbial biomass C(on days 7 and 15) were inhibited by fluxapyroxad, but stimulation was observed thereafter. In contrast, fluxapyroxad addition increased the basal respiration and metabolic quotients(q CO2) and respiratory quotients(QR). Analysis of the PLFA profiles revealed that the total and bacterial biomass(both Gram-positive bacteria(GP) and Gram-negative bacteria(GN)) were decreased within the initial 15 days, whereas those as well as the GN/GP ratio were increased at days 30 and 60. F luxapyroxad input decreased the fungi biomass but increased the bacteria/fungi ratio at all incubation time. Moreover, high fluxapyroxad input(75 mg fluxapyroxad kg–1 soil dry weight) increased the microbial stress level. A principal component analysis(PCA) of the PLFAs revealed that fluxapyroxad treatment s ignificantly shifted the microbial community structure, but all of the observed effects were transient. Biolog results showed that average well color development(AWCD) and functional diversity index(H′) were increased only on day 60. I n addition, the dissipation of fluxapyroxad was slow in soil, and the degradation half-lives varied from 158 to 385 days depending on the concentration tested.     

园林机械（以割草机为代表）用改性PP材料开发与应用

文章从PP材料的改性原理、园林机械用改性PP材料的性能要求出发,全面阐述了园林机械用改性PP材料的开发研制过程,开发出了一系列园林机械用改性PP材料并全面在ZS系列园林机械上得到了应用。     

立式无筛饲料超微粉碎机的研发及质量检测分析

介绍了我国立式无筛饲料超微粉碎机的发展,简述立式无筛饲料超微粉碎机的组成、工作原理和优越性,分析质量检测及立式无筛饲料超微粉碎机技术的发展,展望制定行业标准的预期效果。