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Experimental and numerical evaluation of multidirectional compressive and flexure behavior of three-dimensional printed concrete

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Frontiers of Structural and Civil Engineering 2023年第11期17卷 1643-1661页

作者： Lalit KUMAR Dhrutiman DEY Biranchi PANDA nelson MUTHU Department of Mechanical Engineering Indian Institute of Technology GuwahatiAssam 781039India

Three-dimensional concrete printing(3DCP)can proliferate the industrialization of the construction sector,which is notoriously conservative and indolent toward ***,the mechanical behavior of 3DCP should be characterized and modeled considering the interfaces when its performance is thoroughly compared to that of the existing concrete construction *** study presents an experimental and numerical investigation of uniaxial compression and three-point bending(TPB)tests on extruded 3DCP beams in different loading *** orientation of translational and depositional interfaces with respect to the direction of loading influenced the *** the elastic and post-damage behavior of the 3DCP specimens were compared with those of the conventionally cast specimen under quasi-static loading *** the higher compressive strength of the casted specimen,the flexural strength of the 3DCP specimens was *** study employed the finite element and cohesive zone models of the appropriate calibrated traction-separation law to model fracture in the notched TPB ***,the real-time acoustic emission test revealed the nature of failure phenomenon of three-dimensional-printed specimens under flexion,and accordingly,the cohesive law was *** predicted load-displacement responses are in good agreement with the experimental ***,the effects of cohesive thickness and notch shape on the performance under bending were explored through parametric studies.

关键词： three-dimensional printing anisotropy flexure compression cohesive zone model finite element model

Carboxylesterases in lipid metabolism： From mouse to human

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Protein & Cell 2018年第2期9卷 178-195页

作者： Jihong Lian Randal nelson Richard Lehner Group on Molecular and Cell Biology of Lipids University of Alberta Edmonton Alberta Canada Department of Pediatrics University of Alberta Edmonton Alberta Canada Department of Cell Biology University of Alberta Edmonton Alberta Canada

Mammalian carboxylesterases hydrolyze a wide range of xenobiotic and endogenous compounds, including lipid esters. Physiological functions of car- boxylesterases in lipid metabolism and energy home- ostasis in vivo have been demonstrated by genetic manipulations and chemical inhibition in mice, and in vitro through （over）expression, knockdown of expression, and chemical inhibition in a variety of cells. Recent research advances have revealed the relevance of carboxylesterases to metabolic diseases such as obesity and fatty liver disease, suggesting these enzymes might be potential targets for treatment of metabolic disorders. In order to translate pre-clinical studies in cellular and mouse models to humans, dif- ferences and similarities of carboxylesterases between mice and human need to be elucidated. This review presents and discusses the research progress in structure and function of mouse and human car- boxylesterases, and the role of these enzymes in lipid metabolism and metabolic disorders.

关键词： carboxylesterase lipase lipid lipoprotein iver adipose intestine

Influence of PVD-duplex-treated, Bionic Surface Structures on the Wetting Behavior for Sheet-Bulk Metal Forming Tools

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Journal of Bionic Engineering 2017年第3期14卷 520-531页

作者： Wolfgang Tiilmann Dominic Stangier nelson Filipe Lopes Dias Institute of Materials Engineering TU Dortmund 44227 Dortmund Germany Leonhard-Euler-Strafle 2

Bionic surface structures, inspired by the flora, were developed for Sheet-Bulk Metal Forming （SBMF） in order to locally control the friction condition by adjusting the wetting behavior. Five bionic structures were micromilled on ASP 2023 in annealed as well as hardened and tempered conditions. Subsequently, the structured surfaces were plasma-nitrided and coated with a CrA1N thin film. The influence of the treatment method on the structural geometry was investigated with the aid of a scanning electron microscope and 3D-profilometer. The wetting behaviors of water and deep drawing oil （Berufluid ST6007） on bionic surfaces were evaluated using contact angle measurements. The resulting micro-milled structures exhibit an almost identical shape as their bionic models. However, the roughness of the structured surfaces is influenced by the microstructure. The combination of plasma-nitriding and Physical Vapor Deposition （PVD） leads to an increase in roughness. All bionic struc- tures possess higher contact angles than that of the unstructured surfaces when wetted by water. This can be explained by the fact that the structural elevations block the spreading. When the bionic surfaces are wetted by deep drawing oil, the lubricant spreads in the structural cavities, leading to smaller contact angles. Furthermore, the anisotropy of the structure has an influence on the wetting behavior.

关键词： bionic structures sheet-bulk metal forming CrA1N PVD-duplex treatment wetting behavior

Addressing nonresponse bias in forest inventory change estimation using response homogeneity classifications

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Forest Ecosystems 2023年第1期10卷 125-131页

作者： James A.Westfall Mark D.nelson U.S.Forest Service Northern Research StationYorkPAUSA U.S.Forest Service Northern Research StationSt.PaulMNUSA

Estimating amounts of change in forest resources over time is a key function of most national forest inventories(NFI). As this information is used broadly for many management and policy purposes, it is imperative that accurate estimations are made from the survey sample. Robust sampling designs are often used to help ensure representation of the population, but often the full sample is unrealized due to hazardous conditions or possibly lack of land access permission. Potentially, bias may be imparted to the sample if the nonresponse is nonrandom with respect to forest characteristics, which becomes more difficult to assess for change estimation methods that require measurements of the same sample plots at two points in time, i.e., remeasurement. To examine potential nonresponse bias in change estimates, two synthetic populations were constructed: 1) a typical NFI population consisting of both forest and nonforest plots, and 2) a population that mimics a large catastrophic disturbance event within a forested population. Comparisons of estimates under various nonresponse scenarios were made using a standard implementation of post-stratified estimation as well as an alternative approach that groups plots having similar response probabilities(response homogeneity). When using the post-stratified estimators, the amount of change was overestimated for the NFI population and was underestimated for the disturbance population, whereas the response homogeneity approach produced nearly unbiased estimates under the assumption of equal response probability within groups. These outcomes suggest that formal strategies may be needed to obtain accurate change estimates in the presence of nonrandom nonresponse.

关键词： Disturbance Post-stratification Land use conversion Sample bias

Temporal and spatial anti-aliasing for rendering reflections on water waves

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Computational Visual Media 2021年第2期7卷 201-215页

作者： Namo Podee nelson Max Kei Iwasaki Yoshinori Dobashi Hokkaido University Sapporo060-0814Japan University of California Davis95616USA Wakayama University Wakayama640-8441Japan

The reflection of a bright light source on a dynamic surface such as water with waves can be difficult to render well in real time due to reflection aliasing and *** this paper,we propose a solution to this problem by approximating the reflection direction distribution for the water surface as an elliptical Gaussian *** we analytically integrate the reflection contribution throughout the rendering interval *** method can render in real time an animation of the time integrated reflection of a spherical light source on highly dynamic waves with reduced aliasing and flickering.

关键词： real-time rendering anti-aliasing reflection water surface water waves elliptical Gaussian

Nanogenerator-based bidirectional pressure sensor array and its demonstration in underwater invasive species detection

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Nano Research 2023年第9期16卷 11822-11831页

作者： Yunqi Cao Hongyang Shi Xiaobo Tan nelson Sepúlveda State Key Laboratory of Industrial Control Technology College of Control Science and EngineeringZhejiang UniversityHangzhou 310027China Department of Electrical and Computer Engineering Michigan State UniversityEast LansingMichigan 48824USA

Lakes areas,which cause catastrophic damages in both commercial fishery and ecological ***,current assessment strategies may pose challenges for lake-wide abundance estimation and non-target anadromous species ***,we demonstrate an efficacious species-specific non-destructive sensing system based on porous ferroelectret nanogenerator for in-situ monitoring of lamprey spawning migration using their unique suction *** show that the porous structure enables a redistribution of surface charges under bidirectional deformations,which allows the detection of both positive and negative *** quasi-piezoelectric effect is further validated by quantitative analysis in a wide pressure range of−50 to 60 kPa,providing detailed insights into transduction working *** reliable lamprey detection,a 4×4-pixel sensor array is developed and integrated with a complementary metal-oxide-semiconductor(CMOS)based signal processing array thus constituting a sensing panel capable of recording oral suction patterns in an underwater environment.

关键词： bidirectional pressure sensing nanogenerators self-powered sensor array ferroelectret invasive species detection

Turning the corner from observation to intervention in human genetics

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Journal of Genetics and Genomics 2018年第2期45卷 57-59页

作者： David L.nelson Department of Molecular and Human Genetics Baylor College of Medicine Jan and Dan Duncan Neurological Research Institute

In the early 1990s,shortly after we identified the genetic defect in FMR1 that results in fragile X syndrome（Verkerk et al.,1991）,I attended a conference sponsored by the US National Fragile X *** biannual meeting m... 详细信息

关键词： Turning the corner from observation to intervention in human genetics

Animal behavior can inform conservation policy, we just need to get on with the jobor can it？

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Current Zoology 2014年第4期60卷 479-485页

作者： Ximena J. nelson, Editor School of Biological Sciences University of Canterbury Private Bag 4800 Christchurch New Zealand

1 Conservation Behavior as an Emerging Discipline on the Brink of Success, or Unrealistic Ideal？ It seems intuitively sensible that an understanding of the behavioral characteristics of animals, such as their home ranges, diets, mating systems, and dispersal me- chanisms, may be useful to inform conservation efforts in determining, for example, suitable reintroduction areas, or the design of dispersal corridors.

关键词：行为特征动物减排新兴学科活动范围交配系统疏散通道再引入

Fo screen or not to screen： the prostate cancer dilemma

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Asian Journal of Andrology 2015年第1期17卷 44-45页

作者： nelson N Stone E David Crawford Departments of Urology and Radiation Oncology The Icahn School of Medicine at Mount Sinai New York NY USA Department of Surgery Division of Urology and Radiation Oncology The Anschutz Cancer Center The University of Colorado Health Sciences Center. Aurora. CO. USA.

The European Randomized Study of Screening for Prostate （ERSPC） has updated their previous seminal report on prostate cancer mortality comparing screened men to controls. Now with 13 years follow-up, the rate ratio of prostate cancer mortality was 0.79 favoring the screened population. The authors concluded that there was a ＂substantial reduction in prostate cancer mortality attributable to testing with prostate-specific antigen （PSA）＂ but they also stated that a＂quantification of harms＂ needed to be addressed. The issue of harms was not addressed by the ERSPC （at least not in this report） and hence this additional statement most likely reflects the controversy currently surrounding the risks associated with over-diagnosis and treatment of indolent diseases inadvertently detected by a screening protocol, In addition, the positive results from this trial conflict with those of the prostate, lung, colorectal and ovarian （PLCO）2 study and reouire further elaboration.

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