Environmental enrichment and chronic restraint stress in ICR mice: Effects on prepulse inhibition of startle and Y-maze spatial recognition memory

In most studies regarding the improving or therapeutical effects induced by enriched environment (EE), EE was performed after the stress treatment or in patients with certain diseases. In the current study, the effects of chronic restraint stress (6 h/day) in mice living in an enriched environment or standard environment (SE) were tested. Mice were randomly divided into 4 groups: non-stressed or stressed mice housed in SE or EE conditions (SE, stress + SE, EE, stress + EE). Prepulse inhibition (PPI) of startle was tested after the 2 weeks or 4 weeks stress and/or EE treatment and 1 or 2 weeks withdrawal from the 4 weeks treatment. After the 4 weeks treatment, spatial recognition memory in Y-maze was also tested. The results showed that EE increased PPI in stressed and non-stressed mice after 2 weeks treatment. No effect of EE on PPI was found after the 4 weeks treatment. 4 weeks chronic restraint stress increased PPI in mice housed in standard but not EE conditions. Stressed mice showed deficits on the 1 h delay version of the Y-maze which could be prevented by living in an enriched environment. Our results indicated that living in an enriched environment reversed the impairing effects of chronic restraint stress on spatial recognition memory. However, EE did not change the effects of stress on PPI. (C) 2010 Elsevier B.V. All rights reserved.

Interaction of corticosterone and nicotine in regulation of prepulse inhibition in mice

The aim of the present Study was to investigate if different levels of circulating corticosterone (CORT) modulate the effect of nicotine on prepulse inhibition (PPI), a measure of sensorimotor gating that is disrupted in schizophrenia and other mental illnesses. Four groups of mice were investigated: sham-operated, adrenalectomized (ADX) and implanted with a cholesterol pellet, ADX and implanted with a 10 mg CORT pellet, or ADX and 50 mg, of CORT. Different CORT levels or doses of nicotine did not significantly affect startle responses. Baseline PPI was significantly reduced in mice implanted with the highest dose of CORT. In ADX mice implanted with cholesterol, nicotine treatment influenced PPI depending on the prepulse intensity. In ADX mice implanted with 50 mg of CORT, treatment with 10 mg/kg of nicotine caused a significant increase in PPI at all prepulse intensities. Binding studies showed that corticosterone treatment had significantly affected nicotinic acetylcholine receptor (nAChR) density in the mouse brain. Treatment with 50 mg CORT decreased I-125-epibatidine binding in the globus pallidus and I-125-alpha-bungarotoxin binding in the claustrum. These results suggest a possible interaction of corticosterone and nicotine at the level of the alpha4- and alpha7-type nAChR in the regulation of PPI. In situations of high circulating levels of corticosterone, nicotine may be beneficial to restore disruption of PPI. (C) 2004 Elsevier Ltd. All rights reserved.

Pool boiling heat transfer of ultra-light copper foam with open cells

High speed visualizations and thermal performance studies of pool boiling heat transfer on copper foam covers were performed at atmospheric pressure, with the heating surface area of 12.0 mm by 12.0 mm, using acetone as the working fluid. The foam covers have ppi (pores per inch) from 30 to 90, cover thickness from 2.0 to 5.0 mm, and porosity of 0.88 and 0.95. The surface superheats are from -20 to 190 K, and the heat fluxes reach 140 W/cm(2). The 30 and 60 ppi foam covers show the periodic single bubble generation and departure pattern at low surface superheats. With continuous increases in surface superheats, they show the periodic bubble coalescence and/or re-coalescence pattern. Cage bubbles were observed to be those with liquid filled inside and vented to the pool liquid. For the 90 ppi foam covers, the bubble coalescence takes place at low surface superheats. At moderate or large surface superheats, vapor fragments continuously escape to the pool liquid. Boiling curves of copper foams show three distinct regions. Region I and II are those of natural convection heat transfer, and nucleate boiling heat transfer for all the foam covers. Region III is that of either a resistance to vapor release for the 30 and 60 ppi foam covers, or a capillary-assist liquid flow towards foam cells for the 90 ppi foam covers. The value of ppi has an important effect on the thermal performance. Boiling curves are crossed between the high and low ppi foam covers. Low ppi foams have better thermal performance at low surface superheats, but high ppi foams have better one at moderate or large surface superheats and extend the operation range of surface superheats. The effects of other factors such as pool liquid temperature, foam cover thickness on the thermal performance are also discussed.

耕作方式对土壤线虫群落组成及多样性的影响

对中国科学院沈阳生态实验站潮棕壤农田耕作方式对土壤线虫群落组成及多样性影响的研究表明，撂荒地和免耕玉米地土壤线虫总数有明显的季节变化，撂荒地土壤线虫总数显著高于常规耕作玉米地和免耕玉米地。撂荒地、常规耕作和免耕玉米地土壤线虫优势营养类群均为植物寄生线虫，而捕食-杂食线虫和食真菌线虫占线虫总数的比例相对较低。 本研究共观测到土壤线虫44个属，撂荒地、常规耕作和免耕玉米地分别观测到41、39和34个属。撂荒地线虫优势属为Helicotylenchus和Paratylenchus；常规耕作玉米地优势属为Pratylenchus、Helicotylenchu和Arobeloides；免耕玉米地优势属为Pratylenchus、Helicotylenchus和Filenchus。 常规耕作玉米地土壤食真菌线虫与食细菌线虫的比值（F/B）显著高于撂荒地和免耕玉米地，优势度（λ）显著低于撂荒地和免耕玉米地。撂荒地自由生活线虫成熟度指数（MI）显著高于常规耕作和免耕玉米地，撂荒地植物寄生线虫成熟度指数（PPI）显著低于常规耕作玉米地和免耕玉米地。常规耕作玉米地均匀度指数（J′）显著高于免耕玉米地。 以富集指数（EI）和结构指数（SI）为基础的土壤线虫区系分析表明，撂荒地受到人为干扰较轻，食物网结构较稳定；常规耕作玉米地食物网结构受到人为干扰较重；免耕玉米地介于二者之间。

CO2浓度升高和氮肥管理对土壤线虫群落的影响

大气CO2浓度升高能够对农田生态系统产生一系列的影响。土壤线虫在农田生态系统腐屑食物网中占有重要的地位，能够对外界环境变化作出较迅速的响应。本文利用江苏省江都市小记镇的稻-麦轮作FACE系统研究平台，在2007-2008年小麦生长季，研究了大气CO2浓度升高和不同氮肥处理（高N和低N）对农田土壤线虫群落的影响。 研究结果表明：高氮肥施用情况下, CO2浓度升高显著降低了麦田土壤铵态氮和硝态氮含量。不同氮肥处理中CO2浓度升高条件下土壤可溶性碳的含量显著低于对照，而土壤总有机碳和微生物量碳含量高于对照。 大气CO2浓度升高条件下，麦田土壤线虫群落组成和多样性与对照相比表现出显著差异。CO2浓度升高显著增加了麦田土壤线虫总数、食细菌线虫、食真菌线虫和植物寄生线虫数量。在小麦拔节期和成熟期，低N和高N施用条件下，FACE处理中土壤线虫多样性指数（H’）、成熟度指数（MI和PPI）均低于对照处理，而结构指数（SI）高于对照处理。线虫生态指数的结果表明，大气CO2浓度升高条件下，土壤线虫群落多样性降低，土壤环境受到一定的干扰，食物网趋于结构化。

施用生防颗粒剂对大豆田土壤线虫群落结构和生物多样性的影响

针对大豆生长期内土壤线虫的变化 ,利用自行研制的生防颗粒剂豆丰一号对大豆田土壤线虫的群落结构和生物多样性进行了研究 ,共鉴定出 5目 14科的土壤线虫 ,其中植物寄生线虫是大豆根际土壤线虫的优势营养类群。与对照相比 ,生防颗粒剂处理在大豆的整个生育期抑制了土壤线虫总量和植物寄生线虫群体数量 ,但在大豆生育末期促进了食细菌线虫和杂食 -捕食性营养类群的增加。应用多样性指数H′、成熟度指数MI、均匀度指数J′、丰富度指数SR、优势度指数l和植物寄生线虫成熟度指数PPI分析比较了处理区和对照区土壤线虫生物多样性变化规律 ,其中 ,多样性指数H′、丰富度指数SR和成熟度指数MI较好的反映了生防颗粒剂的施用对大豆田土壤线虫生物多样性的促进作用。

涕灭威对大豆田土壤线虫生物多样性的影响

利用涕灭威处理大豆田,研究土壤线虫群落结构和生物多样性的变化,共鉴定出7目12科17属的土壤线虫,其中植物寄生线虫是大豆根际土壤线虫的优势营养类群,短体属Pratylenchus,茎属Ditylenchus,小杆属Rhabditis和矛线属Dorylaimus是线虫优势属。与对照相比,除开花期因气候干旱外,涕灭威处理在大豆的各个生育期均抑制了土壤线虫总数和各营养类群的群体数量增长,尤其对植物寄生线虫抑制程度更为显著。应用多样性指数H′、成熟度指数MI、均匀度指数J′、丰富度指数SR、优势度指数l和植物寄生线虫成熟度指数PPI分析比较了处理区和对照区土壤线虫生物多样性变化规律,结果显示涕灭威处理显著降低了大豆田土壤线虫的多样性、增加了线虫的优势度指数,各生态指数较好地反映了涕灭威对大豆田土壤线虫生物多样性的干扰作用。