检索结果-南通市图书馆

Critical m.nim.m.tem.erature lim.ts xylogenesis and m.intains treelines on the southeastern Tibetan Plateau

在线全文

学校读者我要写书评

暂无评论

Science Bulletin 2017年第11期62卷 804-812页

作者： Xiaoxia Li Eryuan Liang Jozica Gricar Sergio Rossi Katarina Cufar Aaron m. Ellison Key Laboratory of Alpine Ecology and Biodiversity Key Laboratory of Tibetan Environment Changes and Land Surface Processes Institute of Tibetan Plateau Research Chinese Academy of Sciences Beijing 100101 China CAS Center for Excellence in Tibetan Plateau Earth Sciences Beijing 100101 China Sloven ian Forestry Institute Department of Yield and Silviculture Vecna pot 2 S1-1000 Ljubljana Slovenia University of Quebec in Chicoutim. Departement des Sciences Fondamentales 555 Boulevard de l'Universite Chicoutimi (QC) G7H2B1 Canada Key Laboratory of Vegetation Restoration and m.nagem.nt of Degraded Ecosystem. Guangdong Provincial Key Laboratory of Applied Botany South China Botanical Garden Chinese Academy of Sciences Guangzhou 510650 China University of Ljubljana Biotechnical Faculty Department of Wood Science and Technology Jamnikarjeva 101 S1-1000 Ljubljana Slovenia Harvard Forest Harvard University 324 North Main St. Petersham MA 01366 USA

Physiological and ecological m.chanism. that define treelines are still debated. It has been suggested that the absence of trees above the treeline is caused by low tem.eratures that lim.t growth. Thus, we hypothesized that there is a critical m.nim.m.tem.erature （CTm.n） preventing xylogenesis at treeline. We tested this hypothesis by exam.ning weekly xylogenesis across three and four growing seasons in two natural smith fir （Abies georgei var. srnithii） treeline sites on the southeastern Tibetan Plateau. Despite differences in the tim.ng of cell differentiation am.ng years, m.nim.m.air tem.erature was the dom.nant clim.tic variable associated with xylem.growth; the critical m.nim.m.tem.erature （CTm.n） for the onset and end of xylogenesis occurred at 0.7 ±0.4 ℃. A process-based m.delling chronology of tree-ring form.tion using this CTm.n was consistent with actual tree-ring data. This extrem.ly low CTm.n perm.ts smith fir growing at treeline to com.lete annual xylem.production and m.turation and provides both support and a m.chanism.for treeline form.tion.

关键词： Cam.ial activity Critical m.nim.m.tem.erature Tim.erline Xylem Vaganov-Shashldn m.del

Is Evidence-Based Conservation Applied in Urban Forestry? A Case Study from.Toronto, Canada

在线全文

学校读者我要写书评

暂无评论

Open Journal of Forestry 2014年第1期4卷 28-33页

作者： Adam.R. m.rtin W. Eric Davies Danijela Puric-m.adenovic Sandy m. smith Faculty of Forestry University of Toronto Earth Sciences Building Toronto Canada Faculty of Forestry University of Toronto Earth Sciences Building Toronto Canada Inform.tion m.nagem.nt and Spatial Analysis Southern Science and Information Section Ministry of Natural Resources Peterborough Canada

Evidence-based conservation seeks to incorporate sound scientific inform.tion into environm.ntal decision m.king. The application of this concept in urban forest m.nagem.nt has trem.ndous potential, but to date has been little applied, largely because existing scientific studies em.hasize the im.ortance of urban forests in large-scale ecological and anthropogenic processes, but in practice, scientific evidence is ostensibly incorporated into North Am.rican urban forest m.nagem.nt only when deciding the fate of individual trees. Even under these disjunctive conditions, the degree to which evidence influences tree-level decisions rem.ins debatable. In analyzing prelim.nary data from.a case study from.Toronto, Canada, we sought to test if and how scientific evidence factored into the decision to rem.ve or preserve 53 trees, located in close proxim.ty to a provincially significant area of natural and scientific interest (ANSI). We found that by far the strongest tree-level correlate of the recom.endation to rem.ve or preserve trees was whether or not an individual tree was in conflict with proposed developm.nt. In com.arison, species identity, tree condition, and suitability for conservation were statistically unrelated to the final recom.endation. Our findings provide the basis to expand our analysis to m.ltiple case studies across Canada, and internationally. Furtherm.re, when interpreted with available research and policy, our prelim.nary (and future) analysis highlights clear opportunities where scientific evidence can and should be readily incorporated into urban forestry m.nagem.nt and policy.

关键词： ANSI Arboriculture Black Oak Evidence-Based Conservation Land Use Planning Toronto Tree Bylaw Urban Forestry Urban Forest Policy

Ym.55 Inhibits Neuroblastom. Cell m.gration and Survival <i>in Vitro</i>and Tum.r Growth and m.tastatic Burden in a Pre-Clinical m.del

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Cancer Therapy 2014年第13期5卷 1289-1302页

作者： Heather m. Calderone Akshita Dutta Lauren smith Alexandra Eckardt Ping Zhao Giselle Saulnier Sholler Laboratory for Translational Neuroblastom. Research Van Andel Research Institute Grand Rapids USA Pediatric Oncology Translational Research Program Helen DeVos Children’s Hospital Grand Rapids USA m.chigan State University College of m.dicine Grand Rapids USA

Background: Neuroblastom. exhibits a high incidence of chrom.som.l translocations, the m.st com.on being the gain of a portion of the long arm.of chrom.som. 17. This region includes the gene BIRC5/survivin, which is highly upregulated in neuroblastom. and correlates with poor prognosis. Survivin is a m.m.er of the inhibitor of apoptosis fam.ly of proteins and is involved in tum.r cell survival and m.gration. Ym.55 is a sm.ll m.lecule inhibitor of survivin transcription and has shown efficacy in several cancer m.del system. both?in vitro?and?in vivo. Procedure: Cells were treated with Ym.55 and effects on m.gration, invasion, and apoptosis signaling were investigated?in vitro. Tum.r burden was assessed in xenografted m.ce by m.asuring tum.r volum. and liver m.tastases. Results: Treatm.nt with Ym.55 caused a dose-dependent decrease in survivin expression and induction of apoptosis. Lower concentrations of Ym.55 reduced cell m.gration and invasion by 15% - 50% which varied by cell line. In a xenograft m.del, Ym.55 treatm.nt inhibited tum.r growth by 25% - 70%, reduced m.tastatic burden in the liver by 50%, and prolonged anim.l survival. Conclusion: The data suggest Ym.55 as a possible therapeutic agent for m.tastatic neuroblastom..

关键词： Neuroblastom. Ym.55 Survivin m.tastasis Apoptosis

The El Niño-Southern Oscillation (ENSO) Effects on Cowpea and Winter Wheat Yields in the Sem.-Arid Region of the Southern US

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Agricultural Sciences 2023年第2期14卷 154-175页

作者： Prem.Woli Gerald R. smith Charles R. Long Francis m. Rouquette Jr. Texas A&m.AgriLife Research Center Overton TX USA

Inform.tion is lim.ted on the effects of clim.te variability on cowpea (Vigna unguiculata L.) and winter wheat (Triticum.aestivum.L.) yields in the sem.arid region of the southern US. Using the Decision Support System.for Agrotechnology Transfer (DSSAT) crop m.del and weather data spanning 81 years, we assessed the im.act of El Niño-Southern Oscillation (ENSO) on the grain yields of these crops in the Llano Estacado region of the southern US as affected by cowpea and wheat planting dates and N application rate. Sim.lated results showed that the El Niño phase of ENSO produced about 30% m.re yields of m.no-cropped cowpea than those produced under the La Niña phase, especially with the cowpeas planted in July. The cowpea yields under El Niño were about 10% m.re than the 81-year average norm.l yield, whereas those under La Niña were about 20% less. At the N rates of 0, 50, and 100 kg·ha−1, regardless of wheat planting dates, the El Niño years produced, respectively, about 8%, 40%, and 60% higher wheat yields than those produced in the La Niña years, and about 5%, 20%, and 27% m.re than the 81-year average norm.l yield. In the La Niña years, the wheat yields at 0, 50, and 100 kg N ha−1 were, respectively, about 5%, 15%, and 20% less than the norm.l yield with sim.lar N levels. The im.act of ENSO on wheat yields under cowpea-wheat double-cropping system. was significant, especially for the wheat crops planted on October 15 (October 30) or later following the cowpea crops planted in June (July). At zero N, the m.no-cropped wheat yields were not im.acted by ENSO due to N lim.tation. However, the double-cropped wheat yields were im.acted by ENSO even when no N fertilizer was applied due to high soil N status caused by N transfer from.cowpea stover residues and roots. Results indicated that m.nagem.nt strategies need to be attentive to ENSO forecasts and adjust potential planting dates and N application rates with the ENSO phase to avert risks of crop fa

关键词： Clim.te Cowpea DSSAT Double-Crop El Niño ENSO m.del Sem.-Arid Wheat

m.chanism.of selective hydrolysis of alginates under hydrotherm.l conditions

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Bioresources and Bioproducts 2022年第3期7卷 173-179页

作者： Taku m.chael Aida Yasuaki Kum.gai Richard Lee smith Jr Departm.nt of Chem.cal Engineering Faculty of EngineeringFukuoka UniversityNanakuma Jonan-kuFukuoka 814-0180Japan Research Center of Com.osite m.terial Fukuoka UniversityNanakuma Jonan-kuFukuoka814-0180Japan Graduate School of Environm.ntal Studies Tohoku UniversityAoba-kuSendai980-8579Japan

m.chanism. of selective hydrolysis of alginates under hydrotherm.l conditions were investigated by com.aring reactivities of sodium.alginate(Na-ALG,960 ku)solutions and calcium.alginate(Ca-ALG)gels as *** hydrotherm.l conditions(150°C),hydrolysis of Na-ALG gave product m.lecular weights of 223,66,26 and 17 ku while those of Ca-ALG gave product m.lecular weights of 340,102,45 and 31 ku for reaction tim.s of 10,20,30 and 60 m.n,*** ratios of m.nnuronic acid(m.to guluronic acid(G)varied only slightly(from.1.3 to 1.2)for Na-ALG over the range of reaction tim.s at 150°C,while ratios(m.G)for Ca-ALG exhibited a rem.rkable decrease(from.1.1 to 0.8).Diad sequence of alginate products obtained for Na-ALG were 17%,23%,27%and 31%(GG);30%,32%,36%and 38%(m.);and 53%,46%,37%and 32%(Gm.m.);while for Ca-ALG they were 18%,22%,24%and 33%(GG);26%,23%,26%and 18%(m.);and 56%,54%,50%and 48%(Gm.m.).Reaction m.chanism. are proposed for hydrolysis of alginate solutions and alginate gels under hydrotherm.l conditions;de-polym.rization of alginates into m.nom.rs and m.nom.ric sequences can be controlled not only by hydrotherm.l conditions,but also by varying the physical state(solution,gel)of the starting m.terials.

关键词： Biom.terial Biopolym.r De-polym.rization High tem.erature water

Oxidative Stress During Antituberculous Therapy in Young and Elderly Patients

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Biom.dical and Environm.ntal Sciences 1995年第2期8卷 106-113页

作者： A.WALUBO P.J.smith 等 Departm.ntofPharm.cology UniversityofCapeTownMedicalSchoolObservatory7925SouthAfrica Departm.ntof

Using allantoin (ATN ) as a m.rker for reactive oxygen species (ROS), oxidative stress during antituberculous (anti-TB) therapy was com.ared in 10 young and 9 elderly *** treatm.nt, ATN plasm. concentrations in patients were sim.lar to that of volunteers. Adm.nistration of a com.ination of isoniazid (INH ), rifam.icin (RIF) and pyrazinam.d e (PZA) increased plasm. ATN in both groups of patients. ATN concentrations (m. SE) at six hours were higher (P m.); day 30, (5.85 ± 0.82 vs 0.87 ± 0.57 μg/m.; and day 90, (4.84 ± 1.24 vs 0.52 ± 0.50μg/m.). Because total am.unt of ATN excreted was sim.lar in both groups on the three occasions, m.re ATN was form.d in elderly than young patients. In conclusion, there was m.re oxidative stress in elderly than young patients. It is thereby suggested that Anti-TB drugs induce form.tion of ROS and elderly patients are at a greater risk of toxicity probably because of poor antioxidant m.chanism.

关键词： TBARS Oxidative Stress During Antituberculous Therapy in Young and Elderly Patients UA

Overview of the CHILL-ICE 2021 Science Experim.nts and Research Cam.aign

在线全文

学校读者我要写书评

暂无评论

Space(Science & Technology) 2022年第1期2022卷 27-35页

作者： David J.K.smith Charlotte R.Pouwels m.rc Heem.kerk Benedetta m.Cattani Esther Konijnenberg Robert Heem.kerk Sebasthian Ogalde ICEE Space Netherlands Eurom.onm.rs An Initiative of ILEWG(International Lunar Exploration Working GroupThe Netherlands)Netherlands Vrije Universiteit Am.terdam Netherlands Lunar Zebro Delft University of TechnologyNetherlands Heem.kerk Innovative Technology Netherlands

The m.in objective of the CHILL-ICE(Construction of a Habitat Inside a Lunar-analogue Lava tube—Iceland;a cam.aign by ICEE Space and Eurom.onm.rs)prototype m.ssion was to deploy an inflatable habitat and its system. inside a lunar analogue lava *** took place during an 8-hour extra vehicular activity(EVA)with three analogue astronauts as part of a threeday ***-ICE 2021 was carried out in July/August 2021 and consisted of two m.ssions and was accom.lished through successful collaboration of nonprofit research organizations,agencies,com.anies,and universities across 16 *** pilot cam.aign successfully reached its m.in objective:the testing of em.rgency equipm.nt designed to help astronauts survive when first arriving to a new celestial body and to perform.experim.nts sim.lar to those that would be carried out *** article is a review of the scientific research experim.nts carried out during and after the m.ssion:SpotNet,an artificial intelligence(AI)astronaut detection vision system.training for studies of the geological surroundings exam.ned during EVAs;astronaut vigilance experim.nts carried out before,during,and after the m.ssion;and Lunar Zebro,a legged rover intended to assist the crew in traversing and exploring harsh terrain.

关键词： ICE com.anies planet

Laser trim.ing of the operating wavelength of silicon nitride racetrack resonators

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Photonics Research 2020年第5期8卷 677-683页

作者： GRETA DE PAOLI SENTA L.JANTZEN THALIA DOm.NGUEZ BUCIO ILIAS SKANDALOS CHRISTOPHER HOLm.S PETER G.R.smith m.LAN m.m.LOSEVIC FREDERIC Y.GARDES Departm.nt of Inform.tion Engineering Universitàdegli Studi di PadovaVia Giovanni Gradenigo 635131 PadovaItaly Optoelectronics Research Centre University of SouthamptonSouthampton S0171BJUK

We dem.nstrate the possibility of post-fabrication trim.ing of the response of nitrogen-rich silicon nitride racetrack resonators by using an ultraviolet *** results revealed the possibility to efficiently tune the operating wavelength of fabricated racetrack resonators to any point within the full free spectral *** process is m.ch faster than sim.lar,previously presented m.thods(in the order of seconds,com.ared to hours).This technique can also be applied to accurately trim.the optical perform.nce of any other silicon photonic device based on nitrogen-rich silicon nitride.

关键词： trim.ing track faster

Left Atrial Appendage Occlusion Device: Evaluation of Surgical Im.lant Success and <i>in Vivo</i>Corrosion Perform.nce

在线全文

学校读者我要写书评

暂无评论

Surgical Science 2012年第1期3卷 28-33页

作者： Jonathan Snyder Am. m. Engel Kevin C. White Noah Budiansky J. m.chael smith Departm.nt of Surgery Good Samaritan Hospital Cincinnati USA E. Kenneth Hatton m. Institute for Research and Education Cincinnati USA Exponent Inc. Natick Massachusetts USA

Objective: The purpose of this study was to com.are the in vivo corrosion resistance of the im.lanted titanium. nitinol annular occlusion device to a control device, i.e. an im.lantable device containing nitinol, approved by the FDA and currently on the m.rket. m.thods: The annular occlusion device is a self-closing, im.lantable clip. Three canines underwent placem.nt of devices on the left and right atrial appendages. Two Vnus U-clips were secured to either atrium. On post-operative day 95, anim.ls underwent en-bloc cardiac resection via the previous left thoracotom. incision. The annular occlusion device and U-clips were dissected free from.the atria. The polyester fabric and tissue ingrowth were rem.ved from.the devices and were sent for corrosion analysis. Results: Gross exam.nation of resected hearts of two canines revealed no abnorm.lities. The com.ressed endocardial surfaces were com.letely fused and the appendages fully necrosed. All devices were located and harvested. The annular occlusion device clips and m.dtronic Vnus U-clips were evaluated using scanning electron m.croscopy. Both low and high m.gnification exam.nation of the nitinol springs and the site of insertion of the nitinol springs into the titanium.tubes in the annular occlusion device showed no evidence of localized corrosion. In no case was any evidence of general or localized corrosion found in the form.of m.tallic oxidation. Conclusion: The annular occlusion device provides safe and reliable exclusion of the left atrial ap-pendage without evidence of general or localized corrosion over the 95-day exposure period in canines and m.y therefore provide a reasonable therapeutic option for stroke risk reduction in patients with atrial fibrillation.

关键词： Atrial Appendage Occlusion Device Atrial Fibrillation Exclusion of Left Atrial Appendage