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Nanostructured 3-D Collagen/Nanotube Biocomposites for Future Bone Regeneration Scaffolds

Nano Research 2009年第6期2卷 462-473页

作者： Edelma E.da Silva Heloisa H.M.Della Colleta Andre S.Ferlauto Roberto L.Moreira Rodrigo R.Resende Sergio Oliveira gregory t.kitten Rodrigo G.Lacerda Luiz O.Ladeira Universidade Federal de Minas Gerais Departamento de FísicaLaboratório de NanomateriaisAv.Antônio Carlos662730123-970Belo HorizonteMGBrazil Universidade Federal de Minas Gerais Departamento de MorfologiaAv.Antônio Carlos662730123-970Belo HorizonteMGBrazil

the fi eld of bionanotechnology has been rapidly growing during the last few years and we can now envision a controllable integration between biological and artificial matter,where new biomimetic structures with a wide range of chemical and physical properties will promote the development of a novel generation of medical *** this work we describe a collagen/carbon nanotube composite which has the potential to be used as a scaffold for tissue *** this biocomposite incorporates the advantageous properties of both collagen and carbon nanotubes,it has most of the characteristics that an ideal biomaterial requires in order to be used as an osteoinductive *** biocomposite is bioresorbable and biodegradable and has the desired mechanical rigidity while maintaining a three-dimensional(3-D)nanostructured *** stability and swelling were achieved under fluid environments by varying the amount of carbon nanotubes(CNts)incorporated into the *** variations can dictate the degree of interaction between fibroblastic cells and the ***-of-concept was shown by performing an in vitro induced mineralization of hydroxylapatite crystals under physiological ***,the ability to attach biofunctional groups to the CNt walls can open a new road for tissue regeneration since the combination of CNts with specific growth factors or cellular ligands can create an environment capable of signaling and infl uencing specifi c cell *** observations suggest that collagen/carbon nanotube biocomposites will have important uses in a wide range of biotechnological areas.

关键词： Biomaterials carbon nanotubes collagen tissue engineering biocompatibility

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A numerical model to simulate the transient frictional viscoelastic sliding contact

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Friction 2024年第2期12卷 319-339页

作者： Dongze WANG gregory de BOER Anne NEVILLE Ali GHANBARZADEH School of Mechanical Engineering University of LeedsLeeds LS29JTUK

Sliding motion has always been one of the major concerns when it comes to the analysis of viscoelastic contact problems.A new model simulating the transient sliding contact of smooth viscoelastic surfaces is developed in this *** taking the dry contact friction and the coupling between shear tractions and normal pressure into account,the effect of the early partial slip period,which is often neglected in the study of viscoelastic sliding contact problems,is investigated *** with solutions based on the frictionless assumption,the steady-state pressure profile is found to be slightly different under the effect of the partial slip regime,including a lower peak pressure and the shift of the contacting region in the direction opposite to the sliding ***,the time required for the viscoelastic contact to reach its steady state is delayed owing to the partial slip period preceding the global sliding motion.

关键词： contact mechanics frictional sliding viscoelasticity viscoelastic friction

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Applying Earth Observation technologies to Economic Consequence Modeling:A Case Study of COVID‑19 in Los Angeles County,California

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International Journal of Disaster Risk Science 2024年第1期15卷 18-31页

作者： Fynnwin Prager Marina t.Mendoza Charles K.Huyck Adam Rose Paul Amyx gregory Yetman Kristy F.tiampo California State University Dominguez HillsCarsonCA 90747USA ImageCat Inc.Long BeachCA 90802USA University of Southern California Los AngelesCA 90015USA CIESIN–Center for International Earth Science Information Network Columbia UniversityPalisadesNY 10964USA Cooperative Institute for Research in Environmental Sciences(CIRES) University of Colorado BoulderBoulderCO 80309USA

Earth observation(EO) technologies,such as very high-resolution optical satellite data available from Maxar,can enhance economic consequence modeling of disasters by capturing the fine-grained and real-time behavioral responses of businesses and the *** investigated this unique approach to economic consequence modeling to determine whether crowd-sourced interpretations of EO data can be used to illuminate key economic behavioral responses that could be used for computable general equilibrium modeling of supply chain repercussions and resilience *** applied our methodology to the COVID-19 pandemic experience in Los Angeles County,California as a case *** also proposed a dynamic adjustment approach to account for the changing character of EO through longer-term disasters in the economic modeling *** found that despite limitations,EO data can increase sectoral and temporal resolution,which leads to significant differences from other data sources in terms of direct and total impact *** findings from this analytical approach have important implications for economic consequence modeling of disasters,as well as providing useful information to policymakers and emergency managers,whose goal is to reduce disaster costs and to improve economic resilience.

关键词： Computable general equilibrium models COVID-19 Disaster economic impacts Earth observation Economic consequence analysis Los Angeles County

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High temperature Iron Ethylene Polymerization Catalysts Bearing N,N,N'-2-(1-(2,4-Dibenzhydryl-6-fluorophenylimino)ethyl)-6-(1-(arylphenylimino)ethyl)pyridines

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Chinese Journal of Polymer Science 2024年第2期42卷 188-201,I0007页

作者： Chantsalnyam Bariashir Qiu-Yue Zhang Bayasgalan Ulambayar gregory A.Solan tong-Ling Liang Wen-Hua Sun Institute of Chemistry and Chemical technology Mongolian Academy of SciencesUlaanbaatar13330Mongolia Key Laboratory of Engineering Plastics and Beijing National Laboratory for Molecular Science Institute of ChemistryChinese Academy of SciencesBeijing100190China Department of Chemistry University of LeicesterUniversity RoadLeicesterLE17RHUK State Key Laboratory for Oxo Synthesis and Selective Oxidation Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou730000China

the N,N,N'-ferrous chloride complexes,[2-{CMeN(2,4-(CHPh)_(2)-6-FC_(6)H_(2))}-6-(CMeNAr)C_(5)H_(3)N]FeCl_(2)(Ar=2,6-Me_(2)C_(6)H_(3) Fe1,2,6-Et_(2)C_(6)H_(3)Fe2,2,6-^(i)Pr_(2)C_(6)H_(3) Fe3,2,4,6-Me_(3)C_(6)H_(2) Fe4 and 2,6-Et_(2)-4-MeC_(6)H_(2) Fe5),each possessing one N-2,4-dibenzhydryl-6-fluorophenyl group,were readily synthesized from their respective unsymmetrical bis(imino)pyridines,*** identification of Fe2 highlighted the variation in the steric properties provided by the dissimilar N-aryl *** pre-treatment with either MAO or MMAO,complexes Fe1-Fe5 all displayed,at an operating temperature of 80℃,high activities for ethylene polymerization with levels falling in the order:Fe4> Fe1> Fe5> Fe2> ***,Fe4/MAO displayed the highest activity of 1.94×10^(7) g_(PE)·mol_(Fe)^(-1)·h^(-1) of the study with only a modest loss in performance at 90℃.Generally,the resulting polyethylenes were highly linear(t_(m) range:122-132℃),narrowly disperse and of low molecular weight(M_(w) range:6.73-46.04kg·mol^(-1)),with the most sterically hindered Fe3 forming the highest molecular weight polymer of the ***-group analysis by ^(1)H-and ^(13)CNMR spectroscopy revealed saturated alkyl(n-propyl and i-propyl) and unsaturated vinyl chain ends indicative of the role of both β-H elimination and chain transfer to aluminum as termination *** comparison with previou sly reported iron precatalysts with similar tridentate ligand skeletons,it is evident that the introduction of a large benzhydryl group in combination with a fluorine as the ortho-substituents of one N-aryl group has the effect of enhancing thermal stability of the iron polymerization catalyst whilst maintaining appreciable polymer molecular weight.

关键词： Iron catalyst Ethylene polymerization Linear polyethylene Fluoride effect thermal stability

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高温压缩变形Al-Zn-Mg-Cu合金动态再结晶后的{111}/{111}近奇异晶界

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金属学报 2024年第9期60卷 1165-1178页

作者：刘光辉王卫国 gregory S Rohrer 陈松林燕童芳冯小铮周邦新福建理工大学晶界工程研究所福州350118 福建理工大学材料科学与工程学院福州350118 Department of Materials Science and Engineering Carnegie Mellon UniversityPittsburghPA15213-3890USA 上海大学材料研究所上海200072

提高{111}/{111}近奇异晶界比例可增强Al-Zn-Mg-Cu合金晶界腐蚀抗力,为了解此类晶界形成机理并探索其调控方法,本工作将470℃、12 h和520℃、6 h双级固溶及冷轧后再结晶的Al-Zn-Mg-Cu合金样品分别在450、480和520℃进行应变速率为0.001 ... 详细信息

提高{111}/{111}近奇异晶界比例可增强Al-Zn-Mg-Cu合金晶界腐蚀抗力,为了解此类晶界形成机理并探索其调控方法,本工作将470℃、12 h和520℃、6 h双级固溶及冷轧后再结晶的Al-Zn-Mg-Cu合金样品分别在450、480和520℃进行应变速率为0.001 s^(-1)、真应变为1.20的压缩变形,压缩后立即水冷。采用电子背散射衍射和基于五参数分析的晶界界面匹配定量表征方法对上述3个样品的显微组织和晶界特征分布进行观察分析。结果表明,高温压缩后的显微组织不均匀,存在间隔分明的细晶组织和粗晶组织,其中细晶组织中的晶界以小角度晶界(LAGB)为主,粗晶组织中的晶界以大角度晶界(HAGB)为主;粗、细晶组织中的{111}/{111}近奇异晶界({111}/{111}-NSB)比例均随压缩温度的升高而增大,其中经520℃压缩的试样,其LAGB中的{111}/{111}-NSB占总晶界的比例为8.77%,HAGB中的{111}/{111}-NSB占总晶界的比例为4.53%。进一步考察各试样的应力-应变曲线以及450℃压缩30%时的显微组织特征可见,应变介于0.05~0.70为稳态流变阶段,主要发生初次动态再结晶(DRX),其主要由粗晶及其HAGB构成。应变介于0.70~1.20为二次硬化阶段,主要发生二次DRX,其中不连续DRX(DDRX)和连续DRX(CDRX)同时进行,且优先发生在某些微区;不论是DDRX因形核和核心长大生成的HAGB,还是CDRX因亚晶合并引入的LAGB,均使对应微区的晶粒细化,导致样品总体流变应力急剧上升。二次DRX阶段,CDRX行为随压缩温度的提高而增强,{111}/{111}-NSB比例也随之增加,特别是LAGB中的{111}/{111}-NSB比例快速增加。

关键词： Al-Zn-Mg-Cu合金近奇异晶界晶界界面匹配连续动态再结晶

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transcranial electrical stimulation in neurological disease

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Neural Regeneration Research 2022年第10期17卷 2221-2222页

作者： gregory L.Brown Michael t.Brown Neurished HersheyPAUSA

Increased lifespan is one of society’s greatest achievements,but this longevity increases the prevalence of diseases of aging,such as neurological ***,neurological disorders are the leading cause of disability and the second leading cause of deaths(Feigin et al.,2019).Furthermore,these diseases affect people in low-,medium-,and high-income countries(Feigin et al.,2019).Current technology to modify neurological burden is scarce,which poses numerous challenges for healthcare,global policy,and economic stability(Feigin et al.,2019).to face these challenges,brain stimulation technology,such as transcranial electrical stimulation(tES),has displayed exciting *** et al.(2017)provide a detailed overview of the safety and application of ***,electrodes are attached to the head and a weak current(e.g.,1-2 mA)is applied through the scalp,skull,and into the brain for 10-30 minutes to activate neurons(Antal et al.,2017).the technique is extremely safe with no serious adverse effects reported from thousands of sessions(Antal et al.,2017).the most common side effects are a tingling/itching sensation or redness at the stimulation site(Antal et al.,2017).However,these side effects can be minimized by reducing the electrode-skin impedance,slowly ramping up and ramping down tES,or using topical analgesics(Antal et al.,2017).the development of tES may repair neural dysfunction and stem the oncoming incidence of neurodegenerative disease.

关键词： stimulation sensation electrical

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Angiographic evaluation and management of acute gastrointestinal hemorrhage

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World Journal of Gastroenterology 2012年第11期18卷 1191-1201页

作者： t gregory Walker Gloria M Salazar Arthur C Waltman Division of Vascular Imaging and Intervention Massachusetts General HospitalHarvard Medical SchoolBostonMA 02114United States

Although most cases of acute nonvariceal gastrointestinal hemorrhage either spontaneously resolve or respond to medical management or endoscopic treatment,there are still a significant number of patients who require emergency angiography and transcatheter *** with noninvasive imaging such as nuclear scintigraphy or computed tomography may localize the bleeding source and/or confirm active hemorrhage prior to *** angiographic evaluation should begin with selective catheterization of the artery supplying the most likely site of bleeding,as determined by the available clinical,endoscopic and imaging *** a hemorrhage source is identified,superselective catheterization followed by transcatheter microcoil embolization is usually the most effective means of successfully controlling hemorrhage while minimizing potential *** is now wellrecognized as a viable and safe alternative to emergency *** selected situations transcatheter intra-arterial infusion of vasopressin may also be useful in controlling acute gastrointestinal *** must be aware of the various side effects and potential complications associated with this treatment,however,and recognize the high re-bleeding *** this article we review the current role of angiography,transcatheter arterial embolization and infusion therapy in the evaluation and management of nonvariceal gastrointestinal hemorrhage.

关键词： Angiodysplasia Aneurysm Digital subtrac-tion angiography Contrast media Hemorrhage Radio-nuclide angiography therapeutic embolization

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Cool-season annual pastures with clovers to supplement wintering beef cows nursing calves

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Journal of Animal Science and Biotechnology 2012年第4期3卷 221-226页

作者： Stacey A Gunter Whitney A Whitworth t gregory Montgomery Paul A Beck United States Department of Agriculture Agricultural Research Service Southern Plains Range Research Station University of Arkansas at Monticello Division of Agriculture Southeast Research & Extension Center University of Arkansas Division of Agriculture Southwest Research & Extension Center University of Arkansas

In December of 3 years, 87 beef cows with nursing calves （.594 ± 9.8 kg; calving season, September to November） at side were stratified by body condition score, body weight, cow age, and calf gender and divided randomly into 6 groups assigned to 1 of 6 cool-season annual pastures （0.45 ha/cow） that had been interseeded into a dormant common bermudagrass （Cynodon dactylon [L.] Pers.）/bahiagrass （Paspalum notatum Flugge） sod. Pastures contained 1 of the following 3 seeding mixtures （2 pastures/mixture）： 1） wheat （triticum aestivurn L.） and ryegrass （Lofium multiflorum Lain., WRG）, 2） wheat and ryegrass plus red clover （trifolium pretense L, WRR）, or 3） wheat and ryegrass plus white （trifofium repens L.） and crimson clovers （trifolium incarnatum L., WRW）. All groups had ad libitum access to grass hay （12% crude protein; 58% total digestible nutrients）. the second week in December, cow estrous cycles were synchronized and artificially inseminated. In late December, a bull was placed with each group for 60-d. Data were analyzed with an analysis of variance using a mixed model containing treatment as the fixed effect and year as the random effect. Body weight and condition scores did not differ （P ≥ 0.27） among cows between February and June. Calf birth weights or average daily gain did not differ （P≥ 0.17） among treatments; however, calves grazing pastures with clovers did tend （P= 0.06） to weigh more than calves grazing grass only. Weaning weight per cow exposed to a bull was greater （P= 0.02） for WRR and WRW than WRG. Cows grazing winter-annual pastures containing clovers tended to wean more calf body weight per cow exposed to a bull than cows grazing the grass only pastures.

关键词： Annual ryegrass Beef cows Clovers Nitrogen Pasture 1

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Urban invaders are not bold risk-takers: a study of 3 invasive lizards in Southern California

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Current Zoology 2020年第6期66卷 657-665页

作者： Breanna J.Putman gregory B.Pauly Daniel t.Blumstein Department of Ecology and Evolutionary Biology University of CaliforniaLos AngelesCA90095-1606USA Department of Herpetology and Urban Nature Research Center Natural History Museum of Los Angeles County900 Exposition BoulevardLos AngelesCA90007USA Department of Biology California State UniversitySan BernardinoCA 92407USA

Biological invasions threaten biodiversity worldwide,and therefore,understanding the traits of successful invaders could mitigate their *** comm only invasive species do well in disturbed habitats,such as urban environments,and their abilities to effectively respond to disturbarices could con tribute to their ***,there are non invasive species that also do well in disturbed *** question remains whether urban invaders behave differently in urban environments than noninvaders,which could suggest an"urban-exploiting"*** Southern California,the co-occurrence of in vasive Italia n wall lizards Pod arc is siculus,brown anoles Anolis sagrei,and green anoles ***,and native western fence lizards Sceloporus occidentalis offers an opportunity to test whether invasives exhibit consistent differences in risk-taking within human-altered habitats compared with a native *** predicted that invasive lizards would exhibit more bold behavior by having shorter flight-initiation distances(FIDs)and by being found farther from a refuge(behaviors that would presumably maximize foraging in low-risk environments).Invasive populations had similar or longer FIDs,but were consistently found at distances closer to a ***,invasive lizards in urban habitats were not bolder than a native *** on nearby refuges might help species successfully invade urban habitats,and if a general pattern,may pose an added challenge in detecting or eliminating them.

关键词： antipredator boldness escape behavior invasion reptile urban ecology

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Remembering your A, B, C’s: Alzheimer’s disease and ABCA1

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Acta Pharmaceutica Sinica B 2022年第3期12卷 995-1018页

作者： Cutler t.Lewandowski Megan S.Laham gregory R.J.thatcher Department of Pharmaceutical Sciences University of Illinois College of PharmacyChicagoIL 60612USA Department of Pharmacology and toxicology University of Arizona College of PharmacyTucsonAZ 85721USA

the function of AtP binding cassette protein A1(ABCA1)is central to cholesterol *** ABCA1 expression or activity is implicated in Alzheimer’s disease(AD)and other *** approaches to boost ABCA1 activity have yet to be translated successfully to the *** risk factors for AD development and progression,including comorbid disorders such as type2 diabetes and cardiovascular disease,highlight the intersection of cholesterol transport and *** of ABCA1 can positively impact APOE lipidation,insulin sensitivity,peripheral vascular and blood-brain barrier integrity,and anti-inflammatory *** strategies towards ABCA1-boosting compounds have been described,with a bias toward nuclear hormone receptor(NHR)*** agonists display beneficial preclinical effects;however,important side effects have limited *** particular,ligands that bind liver X receptor(LXR),the primary NHR that controls ABCA1 expression,have shown positive effects in AD mouse models;however,lipogenesis and unwanted increases in triglyceride production are often *** longstanding approach,focusing on LXRβ*** selectivity,is over-simplistic and has *** approaches such as phenotypic screening may lead to small molecule NHR modulators that elevate ABCA1 function without inducing lipogenesis and are clinically translatable.

关键词： Alzheimer’s disease Cardiovascular disease Cholesterol Drug discovery Liver X receptor Nuclear hormone receptor type 2 diabetes

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