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An efficient bifunctional electrocatalyst derived from layer-by-layer self-assembly of a three-dimensional porous Co-N-C@graphene

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Science Bulletin 2019年第14期64卷 968-975页

作者： Shichang Cai Rui Wang william m. Yourey Junsheng Li Haining Zhang Haolin Tang State Key Laboratory of Advanced Technology for materials Synthesis and Processing Wuhan University of Technology Wuhan 430070 China College of Engineering Penn State University Hazleton PA 18202 USA

Three-dimensional (3D) porous carbon-based materials with tunable composition and microstructure are of great interest for the development of oxygen involved electrocatalytic reactions. Here, we report the synthesis of 3D porous carbon-based electrocatalyst by self-assembling Co-metal organic frameworks (mOF) building blocks on graphene via a layer-by-layer technique. Precise control of the structure and morphology is achieved by varying the mOF layer to tune the electrocatalytic properties. The as-produced electrocatalyst exhibits an excellent catalytic activity for the oxygen reduction reaction in 0.1molL^-1 KOH, showing a high onset potential of 0.963V vs. reversible hydrogen electrode (RHE) and a low tafel slope of 54mVdec^-1, compared to Pt/C (0.934V and 52mVdec^-1, respectively). Additionally, it shows a slightly lower potential vs. RHE (1.72V) than RuO2 (1.75V) at 10mAcm^-2 in an alkaline electrolyte. A rechargeable Zn-air battery based on the as-produced 3D porous catalyst demonstrates a high peak power density of 119mWcm^-2 at a cell voltage of 0.578V while retaining an excellent stability over 250 charge-discharge cycles.

关键词： Oxygen reduction reaction Cobalt Three-dimensional Oxygen evolution reaction Graphene

Leaf/shoot level ecophysiology in two broadleaf and two needle-leaf species under representative cloud regimes at alpine treeline

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Journal of Plant Ecology 2016年第6期9卷 762-772页

作者： Adriana Sanchez Nicole m.Hughes william K.Smith Programa de Biología Universidad del RosarioCarrera 24 No.63C-69BogotáDC 110011Colombia Department of Biology Wake Forest University136 Winston HallWinston-SalemNC 27106USA Department of Biology High Point UniversityUniversity Station 3591High PointNC 27262USA

Aims The effects of clouds are now recognized as critically important to the understanding of climate change impacts on ***,few studies have focused specifically on the ecophysiological responses of plants to *** continental mountain ranges are characterized by common convective cloud formation in the afternoons,yet little is known regarding this influence on plant water and carbon *** we compare the ecophysiology of two contrasting,yet ubiquitous growth forms,needle-leaf and broadleaf,under representative cloud regimes of the Snowy Range,medicine Bow mountains,southeastern Wyoming,*** Photosynthetic gas exchange,water use efficiency,xylem water potentials and micrometeorological data were measured on representative clear,overcast and partly cloudy days during the summers of 2012 and 2013 for two indigenous broadleaf(Caltha leptosepala and Arnica parryi)and two needle-leaf species(Picea engelmannii and Abies lasiocarpa)that co-occur *** Findings Reductions in sunlight with cloud cover resulted in more dramatic declines in photosynthesis for the two broadleaf species(ca.50-70%reduction)versus the two conifers(no significant difference).In addition,the presence of clouds corresponded with lower leaf conductance,transpiration and plant water status in all ***,the more constant photosynthesis in conifers under all cloud conditions,coupled with reduced transpiration,resulted in greater water use efficiency(ca.25%higher)than the broadleaf *** differences appear to implicate the potential importance of natural cloud patterns in the adaptive ecophysiology of these two contrasting,but common,plant growth forms.

关键词： gas exchange light response curves water use efficiency xylem water potential

Expansion properties for finite subdivision rules I Dedicated to the memories of william P. Thurston and Lei Tan

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Science China mathematics 2018年第12期61卷 2237-2266页

作者： william J.Floyd Walter R.Parry Kevin m.Pilgrim Department of mathematics Virginia Tech Department of mathematics and Statistics Eastern Michigan University Department of mathematics Indiana University

Among Thurston maps (orientation-preserving, postcritically finite branched coverings of the 2-sphere to itself), those that arise as subdivision maps of a finite subdivision rule form a special family. For such maps, we investigate relationships between various notions of expansion—combinatorial, dynamical, algebraic,and coarse-geometric.

关键词： finite subdivision rule expanding map postcritically finite Thurston map

Application of SWAN model for storm generated wave simulation in the Canadian Beaufort Sea

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Journal of Ocean Engineering and Science 2020年第1期5卷 19-34页

作者： md.Azharul Hoque william Perrie Steven m.Solomon Natural Resources Canada Bedford Institute of OceanographyDartmouthNova Scotia B2Y 4A2Canada Fisheries and Ocean Canada Bedford Institute of OceanographyDartmouthNova Scotia B2Y 4A2Canada

The wave model SWAN(Simulating WAves Nearshore)is implemented for the Canadian Beaufort Sea and storm generated waves are investigated through comparisons between in situ buoy observations and numerical *** are performed for four storms using the SWAN wave *** specifically use SWAN’s non-stationary and two-dimensional modes in a fine resolution nested domain within a coarse resolution *** established whitecapping formulations in SWAN are examined;one is dependent on mean spectral wave steepness and the other is on local spectral *** simulations in the shallow fine resolution domain also consider the effects of bottom friction and nonlinear triad *** the Beaufort Sea study area,wave simulations in which the white capping formulation is dependent on local spectral steepness are better than those where the dependency is on mean spectral steepness;however implementation of bottom friction term and triad mechanisms in the present study does not lead to any notable enhancement in the simulations.

关键词： Arctic Ocean Beaufort Sea mackenzie delta Storm waves SWAN.

Chemoprevention of esophageal adenocarcinoma

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Gastroenterology Report 2020年第4期8卷 253-260,I0001页

作者： Erik J.Snider Andrew m.Kaz John m.Inadomi william m.Grady Division of Gastroenterology Department of Internal MedicineUniversity of Washington School of MedicineSeattleWAUSA Gastroenterology Section VA Puget Sound Health Care SystemSeattleWAUSA Clinical Research Division Fred Hutchinson Cancer Research CenterSeattleWAUSA

Esophageal adenocarcinoma(EAC)is a major cause of cancer-related death,particularly in Western populations,and is rapidly rising in Asian populations at this *** all EACs develop from the precursor lesion Barrett’s esophagus(BE),which is the most significant risk factor for ***,the rates of progression from BE to EAC are low and patients with BE are ***,any strategy for EAC prevention must carry a low risk of harm in order to be clinically *** current EAC-screening and BE-surveillance methods carry some procedural risk and are burdensome,there is an opportunity for chemoprevention,*** or dietary factors that may prevent BE from progressing to EAC.A variety of candidate chemoprevention therapies have been assessed to ***-pump inhibitors(PPIs)are the best studied and have modest EAC-chemoprevention efficacy in BE patients,with a recent randomized trial showing that high-dose PPI may be more effective than low-dose *** and other non-steroidal anti-inflammatory drugs have moderate quality observational and randomized-trial evidence for preventing progression of BE to EAC,but their risks for harm have precluded their routine clinical *** therapies(statins,metformin,female sex hormones)generally do not have strong evidence to support their use in EAC *** progress has been made in this field,there is still a need for more effective and safe chemoprevention therapies for EAC.

关键词： Barrett’s esophagus esophageal adenocarcinoma chemoprevention

Experimental and modeling Study of Forest Fire Effect on Soil Thermal Conductivity

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Pedosphere 2016年第4期26卷 462-473页

作者： Kathleen m.SmITS Elizabeth KIRBY william J.mASSmAN Larry Scott BAGGETT Center for the Experimental Study of Subsurface Environmental Processes Department of Civil and Environmental EngineeringColorado School of Mines USDA Forest Service Rocky Mountain Research Station

An understanding of soil thermal conductivity after a wildfire or controlled burn is important to land management and post-fire recovery efforts. Although soil thermal conductivity has been well studied for non-fire heated soils, comprehensive data that evaluate the long-term effect of extreme heating from a fire on the soil thermal conductivity are limited. The purpose of this study was to evaluate the long-term impact of fire on the effective thermal conductivity of soils by directly comparing fire-heated and no-fire control soils through a series of laboratory studies. The thermal conductivity was measured for ten soil samples from two sites within the manitou Experimental Forest, Colorado, USA, for a range of water contents from saturation to the residual degree of saturation. The thermal conductivity measured was compared with independent estimates made using three empirical models from literature, including the Campbell et al. （1994）, CSt~ and Konrad （2005）, and massman et al. （2008） models. Results demonstrate that for the test soils studied, the thermal conductivity of the fire-heated soils was slightly lower than that of the control soils for all observed water contents. modeling results show that the Campbell et al. （1994） model gave the best agreement over the full range of water contents when proper fitting parameters were employed. Further studies are needed to evaluate the significance of including the influence of fire burn on the thermal properties of soils in modeling studies.

关键词： controlled burn degree of saturation empirical model water content wildfire

Choledochal cysts: Similarities and differences between Asian and Western countries

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World Journal of Gastroenterology 2019年第26期25卷 3334-3343页

作者： George N Baison morgan m Bonds william S Helton Richard A Kozarek Digestive Disease Institute Virginia Mason Medical Center

Choledochal cysts(CCs)are rare bile duct dilatations,intra-and/or extrahepatic,and have higher prevalence in the Asian population compared to Western *** of the current literature on CC disease originates from Asia where these entities are most *** are thought to arise from an anomalous pancreaticobiliary junction,which are congenital anomalies between pancreatic and bile *** similarities in presentation between Eastern and Western patients exist such as female predominance,however,contemporary studies suggest that Asian patients may be more symptomatic on *** though CC disease presents with an increased malignant risk reported to be more than 10%after the second decade of life in Asian patients,this risk may be overstated in Western *** this difference in cancer risk,management guidelines for all patients with CC are based predominantly on observations reported from Asia where it is recommended that all CCs should be excised out of concern for the presence or development of biliary tract cancer.

关键词： Choledochal cyst Cholangiocarcinoma Asian populations Western populations Anomalous pancreaticobiliary junction

Vampiristic behaviors in a patient with traumatic brain injury induced disinhibition

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World Journal of Clinical Cases 2016年第6期4卷 138-141页

作者： william m Hervey Glenn Catalano maria C Catalano mental Health and Behavioral Sciences Service James A. Haley Veterans Hospital Department of Psychiatry and Behavioral Neurosciences University of South Florida Morsani College of Medicine

Vampiristic behaviors are rarely seen clinically and less than 100 cases have been reported in the world literature to date. A distinction is usually made as to whether the patient drinks their own blood or the blood of others. We describe a 38-year-old patient who had vampiristic thoughts and fantasies that began in adolescence, but did not act on these thoughts until after she suffered a traumatic brain injury with a three-week loss of consciousness while serving in the military. Brain imaging showed focal damage to her bilateral frontal lobes. Psychological testing demonstrated impairment of executive function. We review the proposed diagnostic criteria for vampirism and discuss how behavioral disinhibition may have affected the emergence into behavior of her previously inhibited vampiristic thoughts.

关键词： Vamipirism Disinhibition Traumatic brain injury Hematophagia Blood

In situ measurement of ECm rheology and microheterogeneity in embedded and overlaid 3D pancreatic tumor stroma co-cultures via passive particle tracking

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Journal of Innovative Optical Health Sciences 2017年第6期10卷 26-34页

作者： Dustin P.Jones william Hanna Gwendolyn m.Cramer Jonathan P.Celli Department of Physics University of massachusetts Boston Boston MA 02215USA

Tumor growth is regulated by a diverse set of extraellular infuences,including paracrine crosstalk with stromal partners,and biophysical interactions with surrounding cells and *** elucidating the role of physical force and the mechanical properties of the extracellular matrix(ECm)itself as regulators of tumor growth and invasion have been greatly catalyzed by the use of in ritro three-dimensional(3D)tumor *** systems provide the ability to systematically isolate,manipulate,and evaluate impact of stromal components and extracellular mechanics in a platform that is both conducive to imaging and biologically ***,recognizing that mechanoregulatory crosstalk is bi-directional and fully utilizing these models requires complementary methods for in situ measurements of the local mechanical ***,in 3D tumor/fbroblast co-culture models of pancreatic canocer,a discase characterized by its prominent stromal involvement,we evaluate the use of particle-tracking microrhoology to probe dynamic mechanical *** videos of fuorescently labeled polystyrene micro-spheres embedded in ollagen I ECm,we measure spatiotemporal changes in the Brownian motion of probes to report local ECm shear modulus and *** approach reveals st ffening of collagen in fibroblast co-cultures relative to cultures with cancer cells only,which exhibit degraded ECm with heterogeneous *** further show that these effects are dependent on culture geometry with contrast ing behavior for embedded and overlay *** addition to potential application to screening stroma targeted therapeutics,this work also provides insight into how the compoition and plating geometry impact the mechanical propertios of 3D cell cultures that are increasingly widey used in cancer biology.

关键词： microrheology 3D tumor models matrix remodeling mechanobiology stromal depletion