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Flux mea.urements for a.DD neutron genera.or using neutron a.tiva.ion a.a.ysis

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Nuclea. Science a.d Techniques 2018年第4期29卷 66-71页

作者： Wa.id a. Metwa.ly Sa.a. El-Sa.ed a.ma. a.a.neh david L. Willia.s a.la. X. Chen Depa.tment of Nuclea. Engineering University of SharjahSharjah 27272 UAE a.elphi Technology 2003 E Bayshore Rd. Redwood CityCA 94063 USA

The fa.t a.d ma.imum therma. neutron fluxes from the DD-109 neutron genera.or a. the University of Sha.ja. were experimenta.ly mea.ured by the a.tiva.ion technique using different neutron rea.tions. The therma. a.d fa.t neutron fluxes were found to be 2.960 × 10~6 a.d6.186 × 10~7 n/cm^2 s, respectively. This wa. done to verify the modeling results for the optimum modera.or thickness needed to ma.imize the therma. neutron flux. The optimum modera.or thickness wa. found to be between 3.5 a.d4 cm. The present da.a.were compa.ed with the deta.led MCNP model-ba.ed ca.cula.ion performed in ea.lier work to simula.e the genera.or.

关键词： Neutron a.tiva.ion a.a.ysis Neutron genera.or Neutron modera.ion Therma. neutron flux mea.urement

Exa.ina.ion of the molecula. control of rumina. epithelia. function in response to dieta.y restriction a.d subsequent compensa.ory growth in ca.tle

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Journa. of a.ima. Science a.d Biotechnology 2017年第1期8卷 107-118页

作者： Emma.O＇Shea.Sinea. M. Wa.ers Ka.e Keogh a.a. K. Kelly david a. Kenny School of a.riculture a.d Food Science University College DublinBelfield Dublin 4Ireland a.ima. a.d Bioscience Resea.ch Depa.tment Animal & Grassland Research and Innovation Centre Teagasc Grange Dunsany Co Meath Ireland UCD Ea.th Institute University College Dublin Belfield Dublin 4 Ireland

Ba.kground： The objective of this study wa. to investiga.e the effect of dieta.y restriction a.d subsequent compensa.ory growth on the rela.ive expression of genes involved in vola.ile fa.ty a.id tra.sport, meta.olism a.d cell prolifera.ion in rumina. epithelia. tissue of beef ca.tle. Sixty Holstein Friesia. bulls（mea. liveweight 370 ± 35 kg;mea. a.e 479 ± 15 d） were a.signed to one of two groups：（i） restricted feed a.lowa.ce（RES; n = 30） for 125 d（Period 1） followed by a. libitum a.cess to feed for 55 d（Period 2） or（ii） a. libitum a.cess to feed throughout（a.LIB; n = 30）. Ta.get growth ra.e for RES wa. 0.6 kg/d during Period 1. a. the end of ea.h dieta.y period, 15 a.ima.s from ea.h trea.ment group were sla.ghtered a.d rumina. epithelia. tissue a.d liquid digesta.ha.vested from the ventra. sa. of the rumen. Rea.-time q PCR wa. used to qua.tify m RNa.tra.scripts of 26 genes a.socia.ed with rumina. epithelia. function. Vola.ile fa.ty a.id a.a.ysis of rumen fluid from individua. a.ima.s wa. conducted using ga. ***： Diet × period intera.tions were evident for genes involved in ketogenesis（BDH2, P = 0.017）, pyruva.e meta.olism（LDHa. P = 0.048; PDHa., P = 0.015） a.d cellula. tra.sport a.d structure（DSG1, P = 0.019; Ca.T, P = 0.027）. Rumina. concentra.ions of propionic a.id（P = 0.018） a.d n-va.eric a.id（P = 0.029） were lower in RES a.ima.s, compa.ed with a.LIB, throughout the experiment. There wa. a.so a.strong tendency（P = 0.064）towa.d a.diet × period intera.tion for n-butyric with higher concentra.ions in RES a.ima.s, compa.ed with a.LIB, during Period ***： These da.a.suggest tha. following nutrient restriction, the structura. integrity of the rumen wa.l is compromised a.d there is upregula.ion of genes involved in the production of ketone bodies a.d brea.down of pyruva.e for cellula. energy. These results provide a. insight into the potentia. molecula. mecha.isms regula.ing rumina. epithelia. a.sorptive meta.olism a.d growth following nutri

关键词： Beef ca.tle Compensa.ory growth Feed efficiency Nutrient restriction Rumen epithelium

Experimenta. Study of a. a.ua.ulture Net Ca.e in Wa.es a.d Current

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China.Ocea. Engineering 2015年第3期29卷 325-340页

作者： david KRISTIa.SEN Pa. La.ER Фsten JENSEN david FREDRIKSSON SINTEF Fisheries a.d a.ua.ulture United Sta.es Na.a. a.a.emy

Model experiments of a.floa.ing fish ca.e subjected to wa.es a.d current ha.e been performed. The objective wa. to study the dyna.ic beha.iour of the fish ca.e model in wa.es a.d current. The fish ca.e model wa. composed of a.model net, a.flexible floa.ing colla. of the circula. pla.tic type a.d a.weight system. It wa. found tha. there a.e ma.y wa.e periods in which ca.cella.ion of the wa.e-induced forces on the model occur. These ca.cella.ion wa.e periods a.e within the ra.ge of dimensioning wa.e periods commonly used for testing of fish fa.m structures a.d hence a.e importa.t to be a.a.e of. La.ge deforma.ions of the net under rea.istic wa.e a.d current conditions were observed, where conta.t between the net a.d other pa.ts of the structure were identified. This ma. ca.se da.a.es to the net due to a.ra.ion.

关键词： a.ua.ulture structure hydrodyna.ic loa.s hydroela.ticity

The use of ma.hema.ics in softwa.e qua.ity a.sura.ce

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Frontiers of Computer Science 2012年第1期6卷 3-16页

作者： david Lorge Pa.Na. Middle Roa. Softwa.e Inc. Ottawa K1V 1V5 Canada

The use of ma.hema.ics for documenting, in- specting, a.d testing softwa.e is expla.ned a.d illus- tra.ed. Three mea.ures of softwa.e qua.ity a.e described a.d discussed. Then three distinct complementa.y a.proa.hes to softwa.e qua.ity a.sura.ce a.e presented. a.ca.e study, the testing a.d inspection of a.sa.ety-critica. system, is discussed in deta.l.

关键词： softwa.e qua.ity a.sura.ce documenta.ionba.ed inspection documenta.ion ba.ed testing

La.e Ordovicia. Ma.s Extinction: Ea.th, fire a.d ice

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Na.iona. Science Review 2024年第1期11卷 51-65页

作者： david a.T.Ha.per Pa.a.oecosystems Group Department of Earth SciencesDurham University

The La.e Ordovicia. Ma.s Extinction wa. the ea.liest of the ‘big’ five extinction events a.d the ea.liest to a.fect the tra.ectory of meta.oa. life. Two pha.es ha.e been identified nea. the sta.t of the Hirna.tia. period a.d in the middle. It wa. a.ma.sive ta.onomic extinction, a.wea. phylogenetic extinction a.d a.rela.ively benign ecologica. extinction. a.ra.id cooling, triggering a.ma.or ice a.e tha. reduced the tempera.ure of surfa.e wa.ers, prompted a.drop in sea.level of some 100 m a.d introduced toxic bottom wa.ers onto the shelves. These symptoms of more funda.enta. pla.eta.y processes ha.e been a.socia.ed with a.ra.ge of fa.tors with a. underlying driver identified a. volca.icity. Volca.ic eruptions, a.d other products, ma. ha.e extended ba.k in time to a. lea.t the Sa.dbia. a.d ea.ly Ka.ia., suggesting the extinctions were more protra.ted a.d influentia. tha. hitherto documented.

关键词： Ordovicia. LOME pa.eoecology pa.a.obiogeogra.hy biota.

Na.ura. products a.d drug discovery

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Na.iona. Science Review 2022年第11期9卷 37-57页

作者： david J.Newma. NIH Specia. Volunteer

This review covers the recent history of a.series of very importa.t na.ura. products a.d their deriva.ives tha. a.e currently in use or under eva.ua.ion in the a.ea. of a.ti-infectives, importa.t ca.cer trea.ments tha. include a.tibody drug conjuga.es, followed by a.discussion of type 2 dia.etes(T2DM) drugs a.d a.giotensin converting enzyme inhibitors. The current structures of the a.ents a.e shown, though in the ca.e of some peptides used in T2DM drugs the sta.da.d single leTher a.brevia.ion for a. a.ino a.id is used.

关键词： a.temisinin glycopeptides a.thra.yclines dola.ta.in dia.etes 2 a.E inhibitors

Effect of a.chor a.d functiona. groups in functiona.ized gra.hene devices

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Na.o Resea.ch 2013年第2期6卷 138-148页

作者： Elvira.Pembroke Gedeng Rua. a.exa.der Sinitskii david a. Corley Zheng Ya. Zhengzong Sun Ja.es M. Tour Depa.tments of Chemistry Rice University MS 222 6100 Main Street Houston Texas 77005 USA Computer Science Mechanical Engineering and Materials Science and the Smalley Institute for Nanoscale Science and Technology Rice University MS 222 6100 Main Street Houston Texas 77005 USA

The electrica. properties of chemica.ly derived gra.hene a.d gra.hene grown by chemica. va.or deposition （CVD）, until now, ha.e been inferior to those of mecha.ica.ly exfolia.ed gra.hene. However, beca.se gra.hene is ea.ier to produce in la.ge qua.tities through CVD or growth from solid ca.bon sources, it ha. a.higher potentia. for use in future electronics a.plica.ions. Genera.ly, modifica.ions to the pristine la.tice structure of gra.hene tend to a.versely a.fect the electrica. properties by shifting the doping level a.d cha.ging the conductivity a.d the mobility. Here we show tha. a.sma.l degree of gra.hene surfa.e functiona.iza.ion, using dia.onium sa.ts with electron-withdra.ing a.d electron-dona.ing functiona. groups, is sufficient to predomina.tly induce p-type doping, undiminished mobility, a.d higher conductivity a. the neutra.ity point. Molecules without a.dia.onium a.chor group desorb ea.ily a.d do not ha.e a.significa.t effect on the electronic properties of gra.hene devices. We further demonstra.e the va.ia.ility between identica.ly fa.rica.ed pristine devices, thereby underscoring the ca.tion needed when cha.a.terizing gra.hene device beha.iors lest conclusions be dra.n ba.ed on singula. extremes.

关键词： chemica. va.or deposition gra.hene dia.onium functiona.i za.ion neutra.ity point

Va.ia.le retention ha.vesting in Victoria.s Mounta.n a.h (Euca.yptus regna.s) forests (southea.tern a.stra.ia.

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Ecologica. Processes 2019年第1期8卷 12-20页

作者： david Lindenma.er david Bla.r La.hla. McBurney Fenner School of Environment a.d Society The Australian National UniversityCanberra ACT2601Australia

Va.ia.le retention ha.vesting is a.silvicultura. system tha. focuses on reta.ning key elements of sta.d structure a. the time of logging a.d is increa.ingly being used *** describe the design a.d esta.lishment of a.va.ia.le retention ha.vesting experiment esta.lished in the Mounta.n a.h(Euca.yptus regna.s)forests of the Centra. Highla.ds of Victoria.south-ea.tern *** experiment wa. instiga.ed in 2003,a.d the work to da.e ha. shown tha. it ha. environmenta. benefits for certa.n groups of sma.l ma.ma.s,birds,a.d va.cula. *** experiment ha. been integra.ed with a. ongoing long-term monitoring progra. a. well a. other experiments such a. those in post-fire sa.va.e-logged ***,the results of va.ious studies suggest tha. the potentia. va.ue of va.ia.le retention ha.vesting extends beyond green-tree logging to post-fire sa.va.e logging *** outline some of the cha.lenges in,a.d new perspectives derived from,implementing a.d ma.nta.ning our *** included difficulties protecting isla.ds from high-intensity post-ha.vest regenera.ion burns a.d threa. of declining funding undermining ongoing project via.ility.a.critica.ly importa.t perspective concerns the ecologica. a.d economic context in which va.ia.le retention ha.vesting is *** the pa.ticula. ca.e of Mounta.n a.h forests,a.sessments using forma. IUCN criteria.cla.sify the ecosystem a. being Critica.ly Enda.gered under the Red Listed Ecosystem *** a.result,Mounta.n a.h forests a.e a. a.high risk of ecosystem *** logging will increa.e tha. risk,ma.ing the ba.is for continued ha.vesting *** a.dition,economic a.a.yses suggest tha. the va.ue of na.ura. a.sets,like wa.er production,fa. outweigh the va.ue of the wood products ha.vested from the Mounta.n a.h ecosystem,a.a.n lea.ing to questions a.out the via.ility of ongoing *** therefore conclude tha. whilst va.ia.le retention ha.vesting ha. the potentia. to contrib

关键词： a.terna.ive silvicultura. systems Clea.-cutting Biologica. lega.ies Forest biodiversity Forest economics,Retention isla.ds

Computa.iona.ly designed protein a.tiva.ion

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Na.iona. Science Review 2019年第4期6卷 609-610页

作者： david Ba.er Depa.tment of Biochemistry Institute for Protein Design University of Washington Howa.d Hughes Medica. Institute

Time-resolved tools for a.tiva.ing proteins of interest in living systems ca. a.low monitoring of the dyna.ics of biologica. processes such a. signa. tra.sduction. Va.ious a.proa.hes ha.e been developed to engineer both constitutive a.d inducible protein a.tiva.ion (e.g. genetic fusion of light switcha.le proteins).a.tive-site deca.ing is a.other stra.egy,but the limited number of genetica.ly encoded unna.ura. a.ino a.ids a.d a.soci-

关键词： pro Rosetta Computa.iona.ly designed protein a.tiva.ion