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Can inhibition of telomerase increase pancreatic cancer cell's susceptibility to chemotherapeutic reagents?

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Hepatobiliary & Pancreatic Diseases International 2002年第1期1卷 155-160页

作者： thomas j.Ⅲ Fahey Department of Surgery Cornell University Medical College New York NY USA

Objectives: To clarify the inhibition of pancreatic can-cer cells by interference with the hTR component of thetelomerase reverse transcriptase enzymatic complexand evaluate susceptibility of antisense hTR pancreaticcancer cells to chemotherapeutic ***: A 593 bp of full length hTR cDNA was sub-cloned into a mammalian expression vector pcDNA3.1(-) in antisense orientation to construct an antisensehTR expression plasmid. The plasmids were introducedinto Pancl cells, a human pancreatic carcinoma cellline, by lipofectin, and G418-resistant stable trans-formants were expanded. Resulting stable clones werescreened for the presence of hTR insert by PCR withT7 and BGH reverse primers located on the flanks ofthe multiclonal site of pcDNA3.1 vector. Cell growth rate,hTR expression, telomerase activity, and anchorage-in-dependent growth property were analyzed. Finally, sus-ceptibility of antisense hTR cells to chemotherapeuticreagents was ***: Significant downregulation of endogenous hTRwas evident in the antisense-hTR transformed cells,and telomerase activity was markedly decreased com-pared to control cells in standard TRAP assays. Fur-thermore, the proliferation and the anchorage-inde-pendent growth ability in antisense-hTR expressingcells were significantly decreased compared with thecontrol parental cells. However, no crisis or senescencephenomena was observed. Antisense hTR appears toincrease Pancl cell's susceptibility to chemotherapeuticreagent cDDP, but not to differentiation reagent DM-SO, COX2 inhibitor sulinbac, NS-398, curcumin, andchemotherapeutic reagent adriamycin(ADM).Conclusions: These data indicate that hTR is probablya critical component of human telomerase activity andthat downregulation of the RNA component of humantelomerase is an effective target for anticancer strategyand antisense hTR can increase Pancl cell's susceptibilityto cDDP.

关键词： Telomerase hTR Antisense Pancreatic carcinoma cellline chemotherapeutic reagents

The impact of vitamin D deficiency on neurogenesis in the adult brain

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Neural Regeneration Research 2017年第3期12卷 393-394页

作者： Natalie j.Groves thomas H.j.Burne Queensland Brain Institute The University of QueenslandSt.LuciaAustralia Queensland Centre for Mental Health Research The Park Centrefor Mental HealthWacolAustralia

There is increasing evidence from epidemiological studies indicating that vitamin D deficiency during adulthood is associated with adverse brain outcomes in humans（Ginde et al.,2009）and rodents（Groves et al.,2014）... 详细信息

关键词： The impact of vitamin D deficiency on neurogenesis in the adult brain GAD

Multiscale Domain Decomposition Methods for Elliptic Problems with High Aspect Ratios

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Acta Mathematicae Applicatae Sinica 2002年第1期18卷 63-76页

作者： jφrgAarnes thomas Y.Hou Department of Mathematics University of BergenJohs.Brunsgt.125008 BergenNorwayApplied Mathematics217-50CaltechPasadenaCA 91125

In this paper we study some nonoverlapping domain decomposition methods for solving a class of elliptic problems arising from composite materials and flows in porous media which contain many spatial scales. Our preconditioner differs from traditional domain decomposition preconditioners by using a coarse solver which is adaptive to small scale heterogeneous features. While the convergence rate of traditional domain decomposition algorithms using coarse solvers based on linear or polynomial interpolations may deteriorate in the presence of rapid small scale oscillations or high aspect ratios, our preconditioner is applicable to multiple-scale problems without restrictive assumptions and seems to have a convergence rate nearly independent of the aspect ratio within the substructures. A rigorous convergence analysis based on the Schwarz framework is carried out, and we demonstrate the efficiency and robustness of the proposed preconditioner through numerical experiments which include problems with multiple-scale coefficients, as well problems with continuous scales.

关键词： Multiscale elliptic problems Domain decomposition Schwarz methods Porous media

Particle flow simulations with homogenised lattice Boltzmann methods

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Particuology 2017年第5期15卷 1-13页

作者： Mathias j. Krause Fabian Klemens thomas Henn Robin Trunk Hermann Nirschl Institute for Applied and Numerical Mathematics Karlsruhe Institute of Technology 76021 Karlsruhe Germany Institute for Mechanical Process Engineering and Mechanics Karlsruhe Institute of Technology 76021 Karlsruhe Germany

An alternative approach to simulating arbitrarily shaped particles submersed in viscous fluid in two dimensions is proposed, obtained by adapting the velocity parameter of the equilibrium distribution function of a standard lattice Boltzmann method （LBM）. Comparisons of exemplifying simulations to results in the literature validate the approach as well as the convergence analysis. Pressure fluctuations occurring in Ladd＇s approach are greatly reduced. In comparison with the immersed boundary method, this approach does not require cost intensive interpolations. The parallel efficiency of LBM is retained. An intrinsic momentum transfer is observed during particle-particle collisions. To demonstrate the capa- bilities of the approach, sedimentation of particles of several shapes is simulated despite omitting an explicit particle collision model.

关键词： Particulate flow simulationsArbitrarily shaped particlesLattice Boltzmann methodsValidationSedimentation processes

Recent Increased Warming of the Alaskan Marine Arctic Due to Midlatitude Linkages

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Advances in Atmospheric Sciences 2018年第1期35卷 75-84页

作者： james E.OVERLAND Muyin WANG thomas j.BALLINGER NOAA/Pacific Marine Environmental Laboratory Seattle WA 98115USA joint Institute for the Study of Atmosphere and Oceans University of Washington Seattle WA 98115USA Department of Geography Texas State UniversitySan Marcos TX 78666USA

Alaskan Arctic waters have participated in hemispheric-wide Arctic warming over the last two decades at over two times the rate of global warming. During 2008–13, this relative warming occurred only north of the Bering Strait and the atmospheric Arctic front that forms a north–south thermal barrier. This front separates the southeastern Bering Sea temperatures from Arctic air masses. Model projections show that future temperatures in the Chukchi and Beaufort seas continue to warm at a rate greater than the global rate, reaching a change of +4℃ by 2040 relative to the 1981–2010 mean. Offshore at 74°N, climate models project the open water duration season to increase from a current average of three months to five months by 2040. These rates are occasionally enhanced by midlatitude connections. Beginning in August 2014, additional Arctic warming was initiated due to increased SST anomalies in the North Pacific and associated shifts to southerly winds over Alaska, especially in winter 2015–16. While global warming and equatorial teleconnections are implicated in North Pacific SSTs, the ending of the 2014–16 North Pacific warm event demonstrates the importance of internal, chaotic atmospheric natural variability on weather conditions in any given year. Impacts from global warming on Alaskan Arctic temperature increases and sea-ice and snow loss, with occasional North Pacific support, are projected to continue to propagate through the marine ecosystem in the foreseeable future. The ecological and societal consequences of such changes show a radical departure from the current Arctic environment.

关键词： Alaska North Pacific Arctic warm advection polar vortex

Microbial roles equivalent to geological agents of high temperature and pressure in deep Earth

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Science China Earth Sciences 2016年第11期59卷 2098-2104页

作者： XIE ShuCheng LIU Deng QIU Xuan HUANG XianYu thomas j.ALGEO State Key Laboratory of Biogeology and Environmental Geology China University of Geosciences Laboratory of Critical Zone Evolution School of Earth Sciences China University of Geosciences State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences Department of Geology University of Cincinnati

Microbes not only show sensitive responses to environmental changes but also play important roles in geochemical and geophysical systems. It is well known that microbes have caused major changes in surface environments and biogeochemical cycles through Earth history. Microbial processes can also induce the synthesis of certain minerals under Earth-surface conditions that previously were believed to form only under high temperatures and pressures in the deep Earth. For example, microbes can promote the conversion of smectite to illite, synthesis of authigenic plagioclase, precipitation of dolomite, and biotransformation of geolipids. These effects of microbes are due to their large surface/volume ratios, enzyme production, and abundant functional groups. Microbial catalyzation of chemical reactions proceeds through reaction-specific enzymes, a decrease in Gibbs' s free energy, and/or break through the dynamics reaction thresholds via their metabolisms and physiology. Microbes can lower the surface free energy of mineral nuclei via biophysical adsorption due to their large surface/volume ratios and abundant functional groups. The mineral precipitation and transformation processes induced by microbes are functionally equivalent to geological processes operating at high temperatures and pressures in the deep Earth, suggesting that microbial processes can serve as analogs to deep abiotic processes that are difficult to observe.

关键词： Geobiology Microbial functional groups Illitization Plagioclase Dolomite Geolipids

Semi-transparent,flexible,and electrically conductive silicon mesh by capillarity-driven welding of vapor-liquid-solid-grown nanowires over large areas

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Nano Research 2020年第5期13卷 1465-1471页

作者： thomas A.Celano Seokhyoung Kim David j.Hill james F.Cahoon Department of Chemistry University of North Carolina at Chapel HillChapel HillNC 27599-3290USA

Bottom-up synthesis of semiconductor nanowires(NWs)by the vapor-liquid-solid(VLS)mechanism has enabled diverse technological applications for these *** metallic NWs,however,it has been challenging to form large-area interconnected NW ***,we generate centimeter-scale meshes of mechanically and electrically interconnected Si NWs by sequentially growing,collapsing,and joining the NWs using a capillarity-driven welding *** fabricate meshes from VLS-grown NWs ranging in diameter from 20 to 100 nm and find that the meshes are three-dimensional with a thickness ranging from^1 to^10 microns depending on the NW *** extinction measurements reveal that the networks are semi-transparent with a color that depends on the absorption and scattering characteristics of individual ***,active voltage contrast imaging of both centimeter-and micron-scale meshes reveals widespread electrical *** a sacrificial layer,we demonstrate that the mesh can be liberated from the growth substrate,yielding a highly flexible and transparent *** transport measurements both on the growth substrate and on liberated,flexible films reveal electrical conduction across a centimeter scale with a sheet resistance of^160-180 kΩ/square that does not change significantly upon *** the ability to encode complex functionality in semiconductor NWs through the VLS process,we believe these meshes of networked NWs could find application as neuromorphic memory,electrode scaffolds,and bioelectronic interfaces.

关键词： semiconductor nanowire conductive network flexible electronics welding thermal annealing active-voltage contrast

Use of Intermetallic Alloys as Reactive Materials for Warhead Applications

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火炸药学报 2015年第6期38卷 8-10页

作者： jürgen Evers thomas M.Klaptke Department of Chemistry Energetic Materials ResearchLMU Munich

With this communication we want to suggest the system ZrW2,a high-density and very hard intermetallic compound that reacts/burns highly exothermic with air at high *** intermetallic phase should provide a very suitabl... 详细信息

关键词： Cermisch metal intermetallic phase thermites reactive structure material warhead

Bemisia tabaci （Hemiptera： Aleyrodidae） nymphal feeding in cotton （Gossypium hirsutum） leaves

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Insect Science 2007年第5期14卷 375-381页

作者： CHANG-CHI CHU DENNIS A. MARGOSAN jAMES S. BUCKNER thomas P. FREEMAN thomas j. HENNEBERRY USDA ARS US Arid Land Agricultural Research Center Maricopa Arizona USDA ARS San Joaquin Valley Agricultural Science Center Parlier California Biosciences Research Laboratory Fargo North Dakota Electron Microscopy Center North Dakota State University Fargo North Dakota USA

We used brightfield electron microscopy （BEM）, differential interference contrast microscopy （DICM）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, and confocal laser scanning microscopy （CLSM） to investigate the stylet pathways of Bemisia tabaci during nymphal feeding behavior in cotton leaves beginning with penetration of the abaxial leaf surface and ending with stylets in sieve tubes in phloem tissues. Most nymphal stylets within salivary sheaths penetrating leaf tissues made complex turns and developed more than one salivary sheath branch before ending in sieve tubes. The external morphology of the salivary sheaths and their routes between and through leaf cells are described during the present study. Results showed the presence of the stylet within the sieve tubes. B. tabaci nymphs may remove stylets and feed in different sieve tubes. Ten short movies showing the progression of the stylet penetrations from adaxial surface to the sieve tubes are attached to Figures 8-15. The report and movies can be viewed from the internet. Download the movies to a local drive in your computer first for fast upload. The movies are posted on the website http：//***/Services/***？docid=14629. The movies can be used as a teaching aid in biology classes.

关键词： Bemisia tabaci microscopy nymphs feeding stylet sheath stylet