A Simple,Rapid Technique for the Study of the Action of Hydrolytic Enzymes on Insoluble Substrates

A rapid, simple, quantitative technique has been developed for the study of the action of hydrolytic enzymes on certain insoluble substrates. The end point of digestion is indicated by the release of a glass bead, when two pieces of lens paper sealed together by the substrate separate due to its digestion by the enzyme.     

大型油罐环焊缝自动清根方法

目前，在大型油罐焊接施工过程中，对环焊缝初次焊接进行清根，主要有人工方法和自动化机械方法。介绍了自动碳弧气刨、自动砂轮磨削机构、电火花切削机构进行清根的方法；并指出了各种自动清根方法的特点和自动清根所必需的一些辅助装置。自动清根机的使用对大型油罐施工速度的提高起到一定作用。     

循环水工厂化养殖系统中浮球式生物滤器在不同工况下的水处理效果

本试验对浮球式生物滤器在不同工况下的水处理效率进行比较,结果表明:(1)无曝气条件下,随着水流量的降低,滤器的硝化效率呈增加趋势;NH4-N转化率和NO2--N转化率分别由水流量8 m3/h时的15.87%和23.84%增加到水流量2 m3/h时的38.85%和71.37%;COD去除率在4 m3/h的水流量下最高,达到10.33%;另外,不曝气各工况下出水溶氧和pH有所下降。(2)有曝气条件下,滤器水处理效率随水流量降低而增加;NH4-N转化率和NO2--N转化率分别由水流量8 m3/h时的6.45%和51.45%增加到水流量2 m3/h时的32.67%和93.36%;COD去除率在水流量4 m3/h下最高,为12.20%;有曝气各工况下出水溶氧和pH都有所增加。(3)对无曝气和有曝气各工况进行比较,结果显示有曝气组各工况水处理效率优于无曝气组。(4)对试验中各工况的日水处理效果进行比较,认为有曝气条件下水流量维持在6 m3/h为适合生产的最佳工况。     

Force fluctuations in bead packs

Experimental observations and numerical simulations of the large force inhomogeneities present in stationary bead packs are presented. Forces much larger than the mean occurred but were exponentially rare. An exactly soluble model reproduced many aspects of the experiments and simulations. In this model, the fluctuations in the force distribution arise because of variations in the contact angles and the constraints imposed by the force balance on each bead in the pile.     

Lunar sample 14425: characterization and resemblance to high-magnesium microtektites

Measurements by energy-dispersive x-ray analysis of the surface of lunar sample 14425, a large glass bead, yield a noritic composition enriched in aluminum and magnesium and, as compared with other norites, depleted in iron and especially calcium. The sample is close in composition to the most basic microtektites. Spherical inclusions of nickel-iron, flattened where they protrude, are found to be enriched in sulfur and phosphorus, at least at the surface. The inclusions form approximately 1 percent of the volume.     

循环水工厂化养殖系统中浮球式生物滤器在不同工况下的水处理效果

本试验对浮球式生物滤器在不同工况下的水处理效率进行比较,结果表明:(1)无曝气条件下,随着水流量的降低,滤器的硝化效率呈增加趋势;NH4-N转化率和NO2--N转化率分别由水流量8 m3/h时的15.87%和23.84%增加到水流量2 m3/h时的38.85%和71.37%;COD去除率在4 m3/h的水流量下最高,达到10.33%;另外,不曝气各工况下出水溶氧和pH有所下降。(2)有曝气条件下,滤器水处理效率随水流量降低而增加;NH4-N转化率和NO2--N转化率分别由水流量8 m3/h时的6.45%和51.45%增加到水流量2 m3/h时的32.67%和93.36%;COD去除率在水流量4 m3/h下最高,为12.20%;有曝气各工况下出水溶氧和pH都有所增加。(3)对无曝气和有曝气各工况进行比较,结果显示有曝气组各工况水处理效率优于无曝气组。(4)对试验中各工况的日水处理效果进行比较,认为有曝气条件下水流量维持在6 m3/h为适合生产的最佳工况。     

Middle Paleolithic shell beads in Israel and Algeria

Perforated marine gastropod shells at the western Asian site of Skhul and the North African site of Oued Djebbana indicate the early use of beads by modern humans in these regions. The remoteness of these sites from the seashore and a comparison of the shells to natural shell assemblages indicate deliberate selection and transport by humans for symbolic use. Elemental and chemical analyses of sediment matrix adhered to one Nassarius gibbosulus from Skhul indicate that the shell bead comes from a layer containing 10 human fossils and dating to 100,000 to 135,000 years ago, about 25,000 years earlier than previous evidence for personal decoration by modern humans in South Africa.     

Polyolefin spheres from metallocenes supported on noninteracting polystyrene

To obviate the destructive interaction of highly reactive metallocene catalysts with classical silica-based supports while retaining the advantage of supported catalysts, a noninteracting polystyrene support was developed. Supported catalysts for the polymerization of alpha-olefins are prepared by treating lightly cross-linked, chloromethylated polystyrene beads consecutively with a secondary amine, an ammonium salt of a weakly coordinating anion, and a neutral dialkylmetallocene. Catalytic sites are distributed homogeneously throughout the support particle, and the polymerization occurs within the bead, in contrast to traditional surface-supported metallocene catalysts. The copolymerization of ethylene and 1-hexene at 40 degreesC affords discrete spherical polyolefin beads with a size (0.3 to 1.4 millimeters) that varies according to the polymerization time.     

丛枝菌根(AM)真菌扩繁方法的研究进展

结合最新研究成果论述了丛枝菌根(AM)真菌纯培养研究方法的概况.采用活体宿主植物盆钵培养法培养AM真菌的优点是操作方便、简单可靠,缺点是培养周期长、繁殖体的产量少,但目前它仍是AM真菌纯培养的主要方法.玻璃珠分室培养法的优点是能够将培养基质与AM真菌分开,获得纯净的AM真菌菌体;但是其技术含量较高,仅供科学研究和小规模接种剂的生产使用.目前较为理想的纯培养的方法是AM真菌单孢无菌的分室Ri-T-DNA转型胡萝卜根双重离体培养法,将这种方法加以改进,可获得目前最为高效安全的AM真菌孢子菌剂的生产方法.开发丛枝菌根真菌"生物肥料"首要解决的问题就是实现AM真菌的纯培养.     

瘤胃微生物总DNA提取方法的比较

目前如何获得完整的瘤胃微生物总DNA是对瘤胃微生物在分子水平研究中关键的一步。瘤胃微生物总DNA分子片段很大,大概在15kb￣20kb,因此需要选择一种合适的提取方法来获得完整的总DNA片段。笔者研究采用物理方法如玻璃珠研磨震荡法、反复冻融法、超声波破碎法、液氮研磨法等,化学方法如表面活性剂十二烷基磺酸钠(sodiumdodecylsulfate,SDS)、溴化十六烷三甲基铵(CetyltrimethylAmmoniumBromide,CTAB等),酶解法(溶菌酶、蛋白酶K等)相结合,并对其进行比较,选择最佳的提取方法,使其符合以后PCR扩增要求以及其它后续研究工作。试验结果表明用玻璃珠研磨震荡加CTAB提取液的方法、反复冻融加SDS提取液的方法提取的瘤胃微生物总DNA的效果高于其它方法,并且通过电泳以及PCR检测,所提取的DNA的量适于进一步的分子生物学研究。     

磁珠分离法快速提取大肠杆菌质粒DNA

以单分散羧基功能化纳米磁性粒子为固相载体,PEG/NaCl为结合液,对大肠杆菌(Escherichia coli)裂解液中的质粒DNA进行了纯化研究.结果表明:PEG8000质量分数7.5％,NaCl浓度1.25 mol/L,磁珠用量0.9 mg时,在室温下,从1.5 mL大肠杆菌菌液中提取到的质粒DNA量为8.3μg...     

优化金黄色葡萄球菌基因组DNA的提取方法

为提取金黄色葡萄球菌DNA,比较了酶解法、丙酮-酶解法、玻璃珠机械法等破壁方法,确定玻璃珠破壁法为最优提取方法。该方法无需对样品进行增菌,可直接从乳品中提取金黄色葡萄球菌DNA。     

平衡计分卡在图书馆绩效管理中的应用研究

平衡计分卡从财务、客户、内部流程和学习成长四个维度衡量和考核组织内各层次的绩效水平。作者通过例证,为图书馆建立了平衡计分卡的仿真模型,并对其进行了长短期的比较,探讨了图书馆利用平衡计分卡开展绩效管理和战略管理的方法,并讨论了图书馆使用平衡计分卡管理时应注意的一些问题。     

2.5%多杀菌素悬浮剂配方的研制

通过正交优化法得到2.5%多杀菌素悬浮剂的最佳配方:多杀菌素原药2.5%,D-425 1.83%,WP-003 6.17%,乙二醇4.5%,硅酸镁铝1.5%,消泡剂630 0.2%,蒸馏水补足至100%。加工工艺研究发现:使用立式砂磨机,锆珠的最佳用量(ml)是制剂体积(ml)的2.0倍,最佳研磨时间为1.5 h,得到的悬浮剂在pH值6.8~7.0条件下,(54±2)℃热贮14 d,无析水、分层现象,悬浮率85%,倾倒性合格,产品各项指标符合悬浮剂的要求。     

浮顶罐蒸汽除蜡装置失效原因分析及对策

浮顶罐蒸汽除蜡装置失效的原因是施工焊接缺陷和热应力破坏。造成焊接缺陷的原因除设备因素外,主要是施工焊接缺陷对蒸汽除蜡装置运行中产生的热应力未作周密考虑。由于除蜡装置的施焊空间狭窄,因此要强化施工现场和质量监督。在施工中还必须注意校核设计数据和加热盘管的热伸缩量,同时要作好蒸汽膨胀试验和水压试验,发现焊缝缺陷及时补救。     

贵州省林业可持续发展探索——以册亨县林业发展为例

林业的可持续发展关系到国民经济的发展。该文以贵州册亨县林业发展为例,提出了以珠防工程、退耕还林工程、石漠化治理工程和短周期速生丰产用材林建设工程等"四大工程"为发展目标,并阐释了林业可持续发展实施的重大意义。     

SHUTTLE-STREAMING: SYNCHRONIZATION WITH HEAT PRODUCTION IN SLIME MOLD

Two small blobs and a channel excised from a slime mold plasmodium were allowed to fuse into a dumbbell-shaped mass in a thermally insulated Kamiya double chamber equipped with naked bead thermistors in contact with the blobs. Cyclic temperature differences of from 1 X 10(-4) to 5 X 10(-2) deg Celsius were recorded by a sensitive lock-in amplifier method with a basal noise level of less than 2 X 10(-2)deg Celsius and a time constant of 0.5 second. The temperature differences were caused by periodic bursts of heat production synchronized perfectly with the shuttle-streaming cycle and invariably localized at the source rather than the destination of the streaming cytoplasm. The results support the theory that the motive force for cytoplasmic streaming in the slime mold is pressure, probably generated by contraction of elements in the channel walls.     

藏酋猴毛干DNA的3种提取方法

为寻求一种从藏酋猴毛干中提取总DNA的有效方法,从一藏酋猴个体背部剪取数量不等的毛干样品(不含毛囊),经蛋白酶K消化后,分别采用高盐沉淀抽提法、酚氯仿抽提法、纳米磁珠抽提法分离获得用于PCR扩增的模板DNA,通过紫外分光光度计测定OD值并计算出质量浓度,同时进行琼脂糖凝胶电泳和PCR扩增检测,分析3种方法提取藏酋猴毛干DNA的质量差异。每处理设置10个重复。结果表明,纳米磁珠法提取藏酋猴毛干中DNA是一种快捷、简便、经济、高效、安全的有效方法;进行毛发取样时以5～10根较为合适。     

Bioassay of solubilized Bacillus thuringiensis var. israelensis crystals by attachment to latex beads

Solubilized crystals of Bacillus thuringiensis var. israelensis were 7000 times less toxic to Aedes aegypti larvae than intact crystals, presumably because mosquito larvae are filter feeders and selectively concentrate particles while excluding water and soluble molecules. A procedure is described whereby soluble toxins are adsorbed to 0.8-micrometer latex beads, with retention of toxicity. The latex bead assay should make it possible to analyze the structure and mode of action of the mosquito toxin.     

X期鸡胚简易体外培养方法的探索

以原蛋壳为孵化蛋壳,利用塑料袋对鸡胚进行转壳,用保鲜膜或蛋壳皿和石蜡封口,分别对Ⅱ、Ⅱ两种简易方法的X期鸡胚体外培养进行了研究。实验结果表明,方法Ⅰ组鸡胚蚊虫珠期的发育率为72．7％(8／11);方法Ⅰ、Ⅱ组鸡胚8日龄存活率分别为0(0／11)和17．6％(3／17)。