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World Journal of Gastroenterology 2010年第5期16卷 531-537页

作者： Cameron M smith david I Watson Michael Z Michael damian J Hussey department of Surgery Flinders University Room 3D211 Flinders Medical Centre Bedford Park South Australia 5042 Australia department of Gastroenterology & Hepatology Flinders University Bedford Park South Australia 5042 Australia

Barrett's esophagus is a premalignant condition caused by gastroesophageal reflux. Once developed, it can progress through varying grades of dysplasia to esoph-ageal adenocarcinoma. Whilst it is well accepted that Barrett's esophagus is caused by gastroesophageal reflux, the molecular mechanisms of its pathogenesis and progression to cancer remain unclear. MicroRNAs (miRNAs) are short segments of RNA that have been shown to control the expression of many human genes. They have been implicated in most cellular processes, and the role of miRNAs in disease development is be-coming increasingly evident. Understanding altered miRNA expression is likely to help unravel the molecular mechanisms that underpin the development of Barrett's esophagus and its progression to cancer.

关键词： Barrett’s esophagus MicroRNA Esophageal adenocarcinoma Transdifferentiation Tumour suppressor

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从心脏移植术看经验对成本费用的影响作用

国外医学（卫生经济分册） 1991年第2期8卷 43-46页

作者： smith d B 刘江红

以心脏移植术来评价经验的积累对结果的影响作用.以前从外科手术的研究发现,在经验和质量(即死亡率和并发症)之间有明显的一致关系,但关于经验和成本费用关系的研究甚少.传统的手术研究或经营管理模式用于设计经验对累计平均资源消耗的... 详细信息

以心脏移植术来评价经验的积累对结果的影响作用.以前从外科手术的研究发现,在经验和质量(即死亡率和并发症)之间有明显的一致关系,但关于经验和成本费用关系的研究甚少.传统的手术研究或经营管理模式用于设计经验对累计平均资源消耗的四个测定值(死亡率、住院时间、财会单位和费用)的影响,现将此模式进行修饰,用于心脏移植术经验的研究。所得数据与此模式吻合。该经验曲线最陡处是死亡率、最平坦处是费用。本文以此讨论了在研究机构和卫生服务设施的计划和管理的总体考虑方面可能得到的启示。

关键词：心脏移植术经验费用手术成本

Integrating Biodegradable 3-dimensional-Printing into Tracheal Reconstruction

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Open Journal of Regenerative Medicine 2015年第3期4卷 27-33页

作者： Todd A. Goldstein Lee P. smith Benjamin d. smith daniel A. Grande david Zeltsman Orthopedic Research Laboratory Feinstein Institute of Medical Research Manhasset USA Hofstra North Shore-LIJ School of Medicine Hempstead USA division of Pediatric Otolaryngology Steven and Alexandra Cohen Children’s Medical Center New Hyde Park USA department of Orthopedic Surgery North Shore-LIJ Manhasset USA department of Cardiovascular and Thoracic Surgery Long Island Jewish Medical Center New Hyde Park USA

Background: Currently, there is no set standard treatment for long-segment tracheomalacia and stenosis. In this study we set out to explore the potential to create a tissue engineered, biodegradable and three-dimensionally (3d) printed tracheal ring as a first step towards bioengineering a long segment tracheal replacement. Method of Approach: A 3d-Computer aided design (CAd) model was produced with multiple channels to allow for cellular growth while mimicking the native anatomy. The design was optimized to allow for printability, cellular expansion, and integration and 3d printed using a modified commercial 3d printer. Results: The cells grown in the scaffold demonstrated a similar proliferation trend compared to control. Chondrocytes within the 3d printed ring retained their phenotypic properties and did not infer any significant change in flexibility, contour and strength to the scaffold. Conclusion: The combination of living cells and a 3d modeled patient specific graft may address some of the unmet clinical needs in the field of tracheal reconstruction. This proof of concept study represents a first step towards producing a 3d printed and tissue engineered long segment tracheal replacement graft for airway surgery.

关键词： Trachea Tissue Engineering 3d Printing Three dimensional Printing Bioengineering

An Unsteady Two-dimensional Complex Variable Boundary Element Method

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Applied Mathematics 2017年第6期8卷 878-891页

作者： bryce d. Wilkins Joshua Greenberg Brittany Redmond Alan Baily Nicholas Flowerday Adam Kratch Theodore V. Hromadka Randy Boucher Howard d. McInvale Steve Horton department of Mathematics United States Military Academy West Point NY USA

The Complex Variable Boundary Element Method (CVBEM) procedure is extended to modeling applications of the two-dimensional linear diffusion partial differential equation (PdE) on a rectangular domain. The methodology in this work is suitable for modeling diffusion problems with dirichlet boundary conditions and an initial condition that is equal on the boundary to the boundary conditions. The underpinning of the modeling approach is to decompose the global initial-boundary value problem into a steady-state component and a transient component. The steady-state component is governed by the Laplace PdE and is modeled using the Complex Variable Boundary Element Method. The transient component is governed by the linear diffusion PdE and is modeled by a linear combination of basis functions that are the products of a two-dimensional Fourier sine series and an exponential function. The global approximation function is the sum of the approximate solutions from the two components. The boundary conditions of the steady-state problem are specified to match the boundary conditions from the global problem so that the CVBEM approximation function satisfies the global boundary conditions. Consequently, the boundary conditions of the transient problem are specified to be continuously zero. The initial condition of the transient component is specified as the difference between the initial condition of the global initial-boundary value problem and the CVBEM approximation of the steady-state solution. Therefore, when the approximate solutions from the two components are summed, the resulting global approximation function approximately satisfies the global initial condition. In this work, it will be demonstrated that the coupled global approximation function satisfies the governing diffusion PdE. Lastly, a procedure for developing streamlines at arbitrary model time is discussed.

关键词： Complex Variables diffusion Equation Laplace Equation Complex Variable Boundary Element Method (CVBEM) Numerical Techniques for Partial differential Equations

Regioselective Synthesis and Biological Evaluation of 1-Hydroxyl Modified Ailanthinone derivatives as Antimalarials

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Open Journal of Synthesis Theory and Applications 2013年第4期2卷 91-96页

作者： Mahendra d. Chordia William F. McCalmont Kirsten S. smith Philip L. smith division of Experimental Therapeutics Walter Reed Army Institute of Research Silver Spring USA

The triterpene quassinoid ailanthinone is a structurally intricate natural product possessing highly potent antimalarial activity against multidrug resistance plasmodium parasites. Although the mechanism of action of ailanthinone is not completely understood, it is presumed to disrupt regular ribosomal functions by inhibiting parasite protein synthesis. Natural scarcity and low solubility of many quassinoids have impeded their development as potential clinical candidates, but exquisite potency of ailanthinone against Plasmodium remains compelling in the global fight against malaria. Herein, we report the highly selective synthesis of 1-hydroxyl derivatives of ailanthinone, including ester, carbonate, carbamate and sulfonate derivatives. The key feature of the synthesis is a one-step regioselective modification of the 1-hydroxyl group in favor of two other hydroxyl groups at C12 and C13. derivatives were obtained via direct reaction with acyl/sulfonyl chlorides in the presence of a tertiary amine base without any protection-deprotection. In vitro antimalarial evaluations of these derivatives were compared with chloroquine and mefloquine against the Plasmodium falciparum clones, d6, W2, and TM91C235. The results demonstrate that modification of the 1-hydroxyl group is achievable, and the antimalarial activity of these derivatives relative to the parent product is significantly retained, thus paving the way for synthesis of derivatives with improved biological availability and/or increased potency.

关键词： Antimalarials Ailanthinone Triterpenoids Quassinoid Plasmodium Falciparum Multidrug Resistance

Modern Shale Gas Horizontal drilling： Review of Best Practices for Exploration Phase Planning and Execution

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中国石油勘探 2009年第3期14卷 41-50页

作者： Nathaniel Harding Stephen smith John Shelton Mike d. Burnaman Harding Shelton Group Oklahoma City Oklahoma 73102

The challenging characteristics of shale formations often require horizontal drilling to economically develop their potential. While every shale gas play is unique, there are several best practices for the proper planning and execution of a horizontal well. In planning a horizontal well, the optimal method and technology for building inclination and extending the lateral section must be determined. Properly specified logging-while-drilling tools are essential to keep the wellbore within the target formation. Planning must also focus on casing design. doing so will help ensure stability and enable reliable and productive completions. Shales pose a challenge for these elements of well planning due to their thin strata and potentially low mechanical competence when foreign fluids are introduced. Once a plan is developed, executing it is even more important to prove a viable exploration program. Fast, efficient drilling with wellbore control and minimal torque and drag should be the priority. This may be achieved by focusing on fluid hydraulics and rheology and bottom hole assembly. Managed pressure drilling (MPd) will help fast drilling, well control and stability. If MPd can be combined with new generation rotary steerable systems that allow the drill string to maintain rotation, impressive efficiencies are possible. Modern drilling parameter analysis represents the newest opportunity for executing shale gas horizontal wells. A method for ROP analysis to improve operational parameters and equipment selection is also proposed.

关键词：页岩天然气石油地质勘探

Assessment of ecosystem services of rice farms in eastern India

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Ecological Processes 2019年第1期8卷 435-450页

作者： A.K.Nayak Md Shahid A.d.Nayak B.dhal K.C.Moharana B.Mondal R.Tripathi S.d.Mohapatra P.Bhattacharyya N.N.Jambhulkar A.K.Shukla Nuala Fitton Pete smith H.Pathak ICAR-National Rice Research Institute CuttackOdisha 753006India Indian Institute of Soil Sciences NabibaghBhopalMadhya PradeshIndia Institute of Biological&Environmental Sciences University of Aberdeen23 St Machar DriveAberdeen AB243UUUK.

Background:Rice is a major cereal crop and staple food of eastern India,and most farmers depend solely on rice for their *** farming provides both tangible and non-tangible benefits to ecosystems which need to be maintained and *** benefits are provided through ecosystem services(ES)that include both marketable and ***:In this study,the rice farms in eastern India were valued by quantifying the economic value of the services under conventional method of rice cultivation and the gap of ecosystem services value and farm income per unit area were assessed.A stratified random sampling technique was used in this study for selection of agro-climatic zones,districts,blocks,gram panchayat,and study units(households).Soil sampling was also performed for assessing the regulating services(biocontrol of pests,carbon flow,soil erosion,nitrogen fixation),provisioning services(food and by-products),and supporting services(soil fertility,hydrological flow,nutrient cycling,and soil formation).Results:The results indicated that the total economic value of ecosystem services ranged from US$1238 to 1688 ha−1 year−*** marketed(primary production)and non-marketed ecosystem services values ranged from 66–89 to 11–34%of the total,*** of some of the ecosystem services such as cultural services,biodiversity,and gas regulation,which may play a significant role in total ecosystem services,has not been made due to non-availability of data and appropriate methodology for rice *** values of parameters can explain the variability in ecosystem services among the agro-climatic zones in eastern *** of locations based on variability of ecosystem services helps in identifying intervention points for sustaining and improving ecosystem services,while permitting sustainable agro-ecological *** highest total economic gap between ES value and farm income was found in the north central plateau zone(US$

关键词： Ecosystem services Rice farming Economic gap Payment for ecosystem services(PES)

A test of two mechanisms proposed to optimize grassland aboveground primary productivity in response to grazing

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Journal of Plant Ecology 2012年第4期5卷 357-365页

作者： A.K.Knapp d.L.Hoover J.M.Blair G.Buis d.E.Burkepile A.Chamberlain S.L.Collins R.W.S.Fynn K.P.Kirkman M.d.smith d.Blake N.Govender P.O'Neal T.Schreck A.Zinn Graduate degree Program in Ecology and department of Biology Colorado State UniversityFort CollinsCO 80526USA division of Biology Kansas State UniversityManhattanKS 66506USA department of Biological Sciences Florida International UniversityNorth MiamiFL 33181USA department of Biology MSC03-2020University of New MexicoAlbuquerqueNM 87131USA Okavango Research Institute University of BotswanaPrivate Bag 285MaunBotswana School of Biological and Conservation Science University of KwaZulu-NatalPrivate Bag X01Scottsville 3209PietermaritzburgSouth Africa department of Ecology and Evolutionary Biology Yale UniversityNew HavenCT 06520USA Scientific Services Kruger National ParkPrivate Bag X402Skukuza1350South Africa department of Ecology and Evolutionary Biology University of CaliforniaIrvineCA 92697USA

Aims Mesic grasslands have a long evolutionary history of grazing by large herbivores and as a consequence,grassland species have numerous adaptations allowing them to respond favourably to *** empirical evidence has been equivocal,theory predicts that such adaptations combined with alterations in resources can lead to grazing-induced overcompensation in aboveground net primary production(ANPP;grazed ANPP>ungrazed ANPP)under certain *** tested two specific predictions from ***,overcompensation is more likely to occur in annually burned grasslands because limiting nutrients that would be lost with frequent fires are recycled through grazers and stimulate ***,overcompensation of biomass lost to grazers is more likely to occur in unburned sites where grazing has the greatest effect on increasing light availability through alterations in canopy *** We tested these nutrient versus light-based predictions in grazed grasslands that had been annually burned or protected from fire for>20 *** assessed responses in ANPP to grazing by large ungulates using both permanent and moveable grazing exclosures(252 exclosures from which biomass was harvested from 3192 quadrats)in a 2-year *** sites were located at the Konza Prairie Biological Station(KPBS)in North America and at Kruger National Park(KNP)in South *** KPBS,sites were grazed by North American bison whereas in KNP sites were grazed either by a diverse suite of herbivores(*** wildebeest,Burchell’s zebra,African buffalo)or by a single large ungulate(African buffalo).Important Findings We found no evidence for overcompensation in either burned or unburned sites,regardless of grazer ***,there was no support for either mechanism leading to ***,complete compensation of total biomass lost to grazers was the most common response characterizing grazing–ANPP relationships with,in some cases,undercompensation of grass ANPP being of

关键词： aboveground net primary production fire forbs herbivores savanna

Manufacture and characterization of graphene membranes with suspended silicon proof masses for MEMS and NEMS applications

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Microsystems & Nanoengineering 2020年第1期6卷 1050-1066页

作者： Xuge Fan Anderson d.smith Fredrik Forsberg Stefan Wagner Stephan Schroder Sayedeh Shirin Afyouni Akbari Andreas C.Fischer Luis Guillermo Villanueva Mikael Ostling Max C.Lemme Frank Niklaus division of Micro and Nanosystems School of Electrical Engineering and Computer ScienceKTH Royal Institute of TechnologySE-10044 StockholmSweden division of Integrated devices and Circuits School of Electrical Engineering and Computer ScienceKTH Royal Institute of TechnologySE-16440 KistaSweden Faculty of Electrical Engineering and Information Technology RWTH Aachen UniversityOtto-Blumenthal-Str.2552074 AachenGermany Advanced NEMS Group École Polytechnique Fédérale de Lausanne(EPFL)1015 LausanneSwitzerland Silex Microsystems AB 17526 JärfällaSweden AMO GmbH Advanced Microelectronic Center Aachen(AMICA)Otto-Blumnethal-Str.2552074 AachenGermany

Graphene’s unparalleled strength,chemical stability,ultimate surface-to-volume ratio and excellent electronic properties make it an ideal candidate as a material for membranes in micro-and nanoelectromechanical systems(MEMS and NEMS).However,the integration of graphene into MEMS or NEMS devices and suspended structures such as proof masses on graphene membranes raises several technological challenges,including collapse and rupture of the *** have developed a robust route for realizing membranes made of double-layer CVd graphene and suspending large silicon proof masses on membranes with high *** have demonstrated the manufacture of square graphene membranes with side lengths from 7µm to 110µm,and suspended proof masses consisting of solid silicon cubes that are from 5µm×5µm×16.4µm to 100µm×100µm×16.4µm in *** approach is compatible with wafer-scale MEMS and semiconductor manufacturing technologies,and the manufacturing yields of the graphene membranes with suspended proof masses were>90%,with>70%of the graphene membranes having>90%graphene area without visible *** measured resonance frequencies of the realized structures ranged from tens to hundreds of kHz,with quality factors ranging from 63 to *** graphene membranes with suspended proof masses were extremely robust,and were able to withstand indentation forces from an atomic force microscope(AFM)tip of up to~*** proposed approach for the reliable and large-scale manufacture of graphene membranes with suspended proof masses will enable the development and study of innovative NEMS devices with new functionalities and improved performances.

关键词： proof characterization hundreds