Disappearance of acetic acid from the bovine reticulorumen at basal and elevated concentrations of acetic acid.

Disappearance of acetic acid was quantified to determine whether removal of this acid from the reticulorumen is altered when ruminal acetic acid concentrations are elevated. Ruminally fistulated beef steers (n = 3 per experiment; BW = 320 +/- 9 kg) were fed eight times daily a 46% corn-based concentrate:54% mixed hay diet to meet maintenance energy requirements (3.5 kg of DM/d). In situ production of acetic acid, determined by pulsed-continuous infusion of [1-14C]acetic acid, was 530 mmol/h (CV = 12%). Disappearance from the reticulorumen (i.e., presumed absorption) was 460 mmol/h (CV = 2%) or 87% (CV = 2%) of ruminal production. Variation is described within an operational steady state. Acetic acid concentrations were increased by continuous infusion of unlabeled acetic acid into the reticulorumen. Ruminal disappearance (mmol/h) increased when this simulated production was elevated up to and exceeding in situ rates reported previously (530 to 2,700 mmol/h). These data suggest that two-thirds to three-fourths of ruminal acetate production disappeared across the reticuloruminal wall when concentration was elevated; the complement exited from the rumen with the liquid phase. The reticulorumen has an additional capacity to remove acetic acid; however, it does so with an apparent reduced efficiency at higher production rates. Liquid out-flow may affect the efficiency of reticuloruminal disappearance. Sites distal to the rumen become quantitatively important when ruminal acetic acid concentrations are increased.     

花生区组间杂种二代性状鉴定

花生区组四粒红与根茎区组Arachis glabrata杂交果针经离体培养克服了不亲和性,获得杂种。杂种二代性状出现疯狂分离,但有些性状仍分别倾向双亲。经叶片过氧化物同工酶分析,酶带的条数、宽窄、活性强弱及迁移率,杂种与双亲有明显差异,也有共同之处,初步证明了杂种的真实性。     

分子标记用于赤眼蜂分子监测的研究

通过对松毛虫赤眼蜂（Trichogramma dedrolimi Matsumura）以及玉米螟赤眼蜂（Trichogramma ostriniae Pang et Chen）rDNA-ITS2基因的克隆测序，并联机检索GenBank核酸序列库中其它赤眼蜂的相关序列，利用核酸分析软件找到松毛虫赤眼蜂和玉米螟赤眼蜂ITS2序列中一段有鉴别意义的标志，并据此设计出蜂种的特异PCR引物，实现了松毛虫赤眼蜂和玉米螟赤眼蜂rDNA特异区带的PCR扩增。研究表明该特异区带具有种的特异性。我们认为该分子标记技术可用于目前我国生防中常用的松毛虫赤眼蜂和玉米螟蒌眼蜂的分子监测，如田间种群动态监控和寄生效果评估。     

蚕沙中黄酮类化合物的提取工艺

采用L9(3^4)正交试验设计对浙江海宁蚕沙中黄酮类化合物的热回流提取工艺进行了优化，所得出最佳工艺条件为；乙醇浓度为30％，料液比1：30，提取时间3h。     

隔膜压滤机在制糖工业中的应用

本文从技术和经济两方面简要介绍了隔膜滤板在制糖行业中的应用，叙述了隔膜板的优点。     

提高苹果外观质量技术要点

通过深翻改土，增施有机肥，使土壤有机质含量达到1％以上。但要防止氮素过多。     

混合变元中立型微分方程的解的振动准则：献给李森林教授八十寿辰

本文得到了两类混合变元中立型微分方程的解的某些新的振动准则,大大改进了〔[5,7-9〕的结果.并推出了变系数的混合中立型方程.     

如何加强市场经济条件下工程造价管理

本文根据目前工程造价管理的实践，指出了存在的问题，并提出了如何加强市场经济条件下建设工程造价管理的四点具体意见，很有现实意义和指导意义。     

Cloning of plasma membrane H-ATPase gene in Populus euphratica Oliv.

For this paper, the plasma membrane (PM) H -ATPase gene has been cloned from Populus euphratica Oliv. through a homology based strategy. The isolated 3,210 bp cDNA contains a single 2,862 bp open reading frame (ORF) which encodes a putative H -ATPase protein of 953 amino acid residues, with a significant homology to plasma membrane H -ATPase of Primus persica, Phaseolus vulgaris, Sesbania rostrata and Daucus carota. The predicted protein has a molecular weight of 104,553 Da. The copy number analysis revealed multiple copies of the PM H -ATPase in the P. euphratica genome after digestion of their genomic DNA by the restriction enzymes EcoRI, NdeⅠ, FbaⅠand BglⅡ, and Southern blot.     

吃水果也有小学问

生活中人们吃水果一般比较随便，不会做过多的考虑。受传统观念或媒体的影响，大多人只知道吃水果对身体有好处，一般很少有吃水果方面的知识。可吃水果也有些小学问，水果性有寒热，对不同人群有不同的适合。不同水果有不同的营养元素，有时会和其他食物产生营养低消作用。所以科学地吃水果，对我们的健康也很重要，作为一名搞食物营养方面的人有义务让人们多了解一下这方面的知识。