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Cover Crop and Irrigation Effects on Soil Microbial Communities and Enzymes in Semiarid Agroecosystems of the Central Great Plains of north America

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Pedosphere 2016年第2期26卷 192-205页

作者： Francisco J. CAlDEROn David nIElSEn Veronica ACOSTA-MARTInEZ Merle F. VIGIl drew lYOn usDA-ARS Central Great Plains Research Station Akron CO 80720 USA usDA-ARS Cropping Systems Research Laboratory Wind Erosion and Water Conservation Unit Lubbock TX 79415 USA Department of Crop and Soil Sciences Washington State University Pullman WA 99164-6420 USA

Cover crops can have beneficial effects on soil microbiology by increasing carbon （C） supply, but these beneficial effects can be modulated by precipitation conditions. The objective of this study was to compare a fallow-winter wheat （Triticum aestivum l.） rotation to several cover crop-winter wheat rotations under rainfed and irrigated conditions in the semiarid us High Plains. Experiments were carried out at two sites, Sidney in nebraska, and Akron in Colorado, usA, with three times of soil sampling in 2012--2013 at cover crop termination, wheat planting, and wheat maturity. The experiments included four single-species cover crops, a 10-species mixture, and a fallow treatment. The variables measured were soil C and nitrogen （n）, soil community structure by fatty acid methyl ester （FAME） profiles, and soil β-glucosidase,β-glucosaminidase, and phosphodiesterase activities. The fallow treatment, devoid of living plants, reduced the concentrations of most FAMEs at cover crop termination. The total FAME concentration was correlated with cover crop biomass （R = 0.62 at Sidney and 0.44 at Akron）. by the time of wheat planting, there was a beneficial effect of irrigation, which caused an increase in myeorrhizal and protozoan markers. At wheat maturity, the cover crop and irrigation effects on soil FAMEs had subsided, but irrigation had a positive effect on the β-glucosidase and phosphodiesterase activities at Akron, which was the drier of the two sites. Cover crops and irrigation were slow to impact soil C concentration. Our results show that cover crops had a short-lived effect on soil microbial communities in semiarid wheat-based rotations and irrigation could enhance soil enzyme activity. In the semiarid environment, longer time spans may have been needed to see beneficial effects of cover crops on soil microbial community structure, soil enzyme activities, and soil C sequestration.

关键词： crop rotation enzyme activity FAME profile fatty acid methyl ester winter wheat

Effects of amendments of paper mill sludge and nutrients on soil surface CO2 flux in northern hardwood forests

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Journal of Forestry Research 2005年第4期16卷 265-269页

作者： WAnG Chuan-kuan drew C. Feldkirchner Stith T. Gower Jim Ferris Eric l. Kruger College of Forestry Northeast Forestry University Harbin 150040 China Department of Forest Ecology and Management University of Wisconsin 1630 Linden Dr. Madison WI53706 USA Champion International Corporation W6852 Hwy. US2 HCR Box 121A Norway MI49870 USA

Safe and economical disposal of paper mill sludge is a key consideration for forest products industry. A study was conducted to examine the effects of amendments of sludge and nutrients on soil surface CO2 flux （Rs） in northern hardwood forests and to quantify the relationship among Rs, soil temperature, and moisture in these stands. The experiment was a randomized complete block design that included sludge-amended, fertilized, and control treatments in sugar maple （Acer saccharum Marsh） dominated hardwood forests in the Upper Peninsula of Michigan, usA. Results showed that Rs was positively correlated to soil temperature （R^2 = 0.80, p 〈 0.001）, but was poorly correlated to soil moisture. Soil moisture positively affected the Rs only in the sludge-amended treatment. The Rs was significantly greater in the sludge-amended treatment than in the fertilized （p = 0.033） and the control （p = 0.048） treatments. The maximum Rs in the sludge-amended treatment was 8.8 μmol CO2 · m^ 2. s^-1, 91% and 126% greater than those in the fertilized （4.6 μmol CO2 · m^-2· s^-1） and control （3.9 μmol CO2· m^- 2· s^-1） treatments, respectively. The Rs did not differ significantly between the fertilized and control treatments. The difference in Rs between sludge-amended and the other treatments decreased with time following treatment.

关键词： Paper mill sludge Fertilization Soil surface CO2 flux Environmental factor

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CDC专题会诊：预防青少年暴力

上海预防医学 2017年第10期29卷 819-821页

作者： Corinne David-Ferdon Thomas R.Simon Howard Spivak Deborah Gorman-Smith sheila.b.Savannah Robert l.listenbee John Iskander 苏慧佳(译) 陆仁敏(审校) Division of Violence Prevention National Center for Injury Prevention and ControlCDC national Institute of Justice US Department of Justice University of Chicago Houston Department of Health and Human Services Office of Juvenile Justice and Delinquency Prevention US Department of Justice Office of the Director CDC 不详

青少年暴力是指发生在10-24岁人群中的,故意以个人体力或能力威胁、伤害他人的事件,这些参与其中的年轻人或是受害者,或是侵犯者,或是目击者。典型的青少年暴力表现为年轻人伤害其他年轻人,且表现形式多有不同。可以举出的例子有：打架... 详细信息

青少年暴力是指发生在10-24岁人群中的,故意以个人体力或能力威胁、伤害他人的事件,这些参与其中的年轻人或是受害者,或是侵犯者,或是目击者。典型的青少年暴力表现为年轻人伤害其他年轻人,且表现形式多有不同。可以举出的例子有：打架、欺凌、武器威胁,以及帮派有关的暴力。不同形式的青少年暴力导致的伤害形式也有不同,包括身体的伤害,例如伤残或死亡;

关键词：青少年暴力 CDC 伤害他人预防会诊专题受害者

Arctic ground squirrel neuronal progenitor cells resist oxygen and glucose deprivation-induced death

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World Journal of biological Chemistry 2016年第1期7卷 168-177页

作者： Kelly l drew Matthew Wells Rebecca McGee Austin P Ross Judith Kelleher-Andersson Institute of Arctic biology Univer-sity of Alaska neuronascent Inc. lifeline Cell Technology

AIM: To investigate the influence of ischemia/reperfusion on arctic ground squirrel(AGS) neuronal progenitor cells(nPCs), we subjected these cultured cells to oxygen and glucose ***: AGS nPCs were expanded and differentiated into nPCs and as an ischemia vulnerable control, commercially available human nPCs(hnPCs) were seeded from thawed nPCs. nPCs, identified by expression of TUJ1 were seen at 14-21 d in vitro(DIV). Cultures were exposed to control conditions, hypoxia, oxygen and glucose deprivation or glucose deprivation alone or following return to normal conditions to model reperfusion. Cell viability and death were assessed from loss of ATP as well as from measures of alamarb lue~ and lactate dehydrogenase in the media and from counts of TUJ1 positive cells using immunocytochemistry. Dividing cells were identified by expression of Ki67 and phenotyped by double labeling with GFAP, MAP2 ab or TUJ1. RESUlTS: We report that when cultured in neuralife^(TM), AGS cells remain viable out to 21 DIV, continue to express TUJ1 and begin to express MAP2 ab. Viability of hn PCs assessed by fluorescence alamarb lue(arbitrary units) depends on both glucose and oxygen availability [viability of hnPCs after 24 h oxygen glucose deprivation(OGD) with return of oxygen and glucose decreased from 48151 ± 4551 in control cultures to 43481 ± 2413 after OGD, P by contrast, when AGS nPCs are exposed to the same OGD with reperfusion at 14 DIV, cell viability assessed by alamar blue increased from 165305 ± 11719 in control cultures to 196054 ± 13977 after OGD. likewise AGS nPCs recovered ATP(92766 ± 6089 in control and 92907 ± 4290 after modeled reperfusion; arbitrary luminescence units), and doubled in the ratio of TUJ1 expressing neurons to total dividing cells(0.11 ± 0.04 in control cultures vs 0.22 ± 0.2 after modeled reperfusion, P ntaining AGS nPCs for a longer time in culture lowered resistance to injury, however, did not impair proliferation of

关键词： neurogenesis neuronal progenitor Hypoxia tolerance Hibernation

“黑暗”世界的别样解读——马克·吐温及其作品中的亚裔移民

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学习与探索 2018年第4期 144-150页

作者： Hsuan l.Hsu 尚菲菲美国加州大学戴维斯分校英语系加利福尼亚州戴维斯95616 沈阳工业大学外国语学院沈阳110870

马克·吐温的小说或显性或隐性地刻画了不同种族的群体,结合时代背景对这些作品进行上下文分析会促使我们运用更广泛的方法思考问题,例如他的文学中如何反映不同种族群体的紧张关系,如何评判、比较种族化过程,如何转换结构种族主义体系... 详细信息

马克·吐温的小说或显性或隐性地刻画了不同种族的群体,结合时代背景对这些作品进行上下文分析会促使我们运用更广泛的方法思考问题,例如他的文学中如何反映不同种族群体的紧张关系,如何评判、比较种族化过程,如何转换结构种族主义体系的解读,如何补充聚焦于种族偏见的研究成果等等。

关键词：马克.吐温(Mark Twain) 小说殖民文学种族主义亚裔移民

Effect of Androstenedione on Adipogenesis in Murine C3H10T1/2 Mesenchymal Cells

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Open Journal of Endocrine and Metabolic Diseases 2015年第2期5卷 9-18页

作者： Pandurangan ramaraj Jorge n. Artaza Indrani Sinha-Hikim Wayne E. Taylor Department of biochemistry Kirksville College of Osteopathic Medicine A.T. Still University of Health Sciences Kirksville MO USA Division of Endocrinology Charles R. Drew University of Medicine and Science Los Angeles CA USA Department of Health and life Sciences Charles R. Drew University of Medicine and Science Los Angeles CA USA

Clinical trials of weak androgen androstenedione (AD) administered at a high concentration, showed an increase in muscle mass in men like strong androgens testosterone (T) and dihydrotestosterone (DHT), but did not show any inhibitory effect on fat mass unlike strong androgens. This observation prompted us to check the in-vitro effect of AD on adipogenesis using mouse mesenchymal multipotent cells (C3H10T1/2), which can differentiate into both myoblasts and adipocytes. Results indicated that AD inhibited adipogenesis at 10 nM, 100 nM and 1 μM concentrations, but not at 10 μM concentration. AD did not inhibit adipogenesis at 10 μM concentration and also did not inhibitmyogenesis at 10 μM concentration. Addition of bicalutamide, an androgen receptor (AR) antagonist decreased myogenesis and increased adipogenesis, indicating that the effect of AD was mediated through AR. Another weak androgen dehydroepiandrosterone (DHEA) also showed the same pattern of adipogenesis in 10T1/2 cells. AD also showed a similar pattern of adipogenesis in 3T3-l1 preadipocyte cells. Thus, the in-vitro results of AD on adipogenesis correlated with the in-vivo results of AD on fat-mass from clinical trials and suggested a possible difference in biological action between weak androgens (AD, DHEA) and strong androgens (T, DHT) on adipogenesis. Since the biological action of AD was mediated through AR, this physiological difference onadipogenesis could be due to the nature (partial agonist/antagonist) of AD binding to AR.

关键词： Androstenedione Adipogenesis Myogenesis Androgen Receptor bicalutamide