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Three-dimensional simulation of liquid injection,film formation and transport,in fluidized beds

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Particuology 2009年第5期7卷 337-346页

作者： Paul Zhao Peter J. O'Rourke Dale snider CPFD Software LLCAlbuquerqueNM 87111USA CFD d'OR Software and Consulting LLCLos AlamosNM 87544USA

Liquid injection, and film formation and transport in dense-phase gas-solids fluidized beds are numerically simulated in three dimensions using a collisional exchange model that is based on the mechanism that collisions cause transfer of liquid mass, momentum, and energy between particles. In the model, each of the particles is represented by a solid core and a liquid film surrounding the core. The model is incorporated in the framework of the commercial code Barracuda developed by CPFD Software. The commercial software is an advanced CFD-based computational tool where the particles are treated as discrete entities, calculated by the MP-PIC method, and tracked using the Lagrangian method. Details of the collisional liquid transfer model have been previously presented in O＇Rourke, Zhao, and snider （2009）; this paper presents new capabilities and proof-testing of the collision model and a new method to better quantify the penetration length. Example calculations of a fluidized bed without liquid injection show the expected effect of collisions on the reduction of granular temperature （fluctuational kinetic energy） of the bed. when applied to liquid injection into a dense-phase fluidized bed under different conditions, the model predicts liquid penetration lengths comparable to the experiments. In addition, the simulation reveals for the first time the dynamic mixing of the liquid droplets with the bed particles and the transient distribution of the droplets inside the bed.

关键词： MP-PIC Liquid injection Fluidized bed Particle collisions CPFD Jet penetration

Talin and kindlin： the one-two punch in integrin activation

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Frontiers of Medicine 2014年第1期8卷 6-16页

作者： Feng Ye Adam K. snider Mark H. Ginsberg Department of Medicine University of California San Diego La Jolla CA 92093 USA

Proper cell-cell and cell-matrix contacts mediated by integrin adhesion receptors are important for development, immune response, hemostasis and wound healing. Integrins pass trans-membrane signals bidirectionally through their regulated affinities for extracellular ligands and intracellular signaling molecules. Such bidirectional signaling by integrins is enabled by the conformational changes that are often linked among extracellular, transmembrane and cytoplasmic domains. Here, we review how talin-integrin and kindlin-integrin interactions, in cooperation with talin-lipid and kindlin-lipid interactions, regulate integrin affinities and how the progress in these areas helps us understand integrin-related diseases.

关键词： signal transduction transmembrane domain nanodisc integrin talin kindling cell adhesion

A Statistical Growth Property of Plant Root Architectures

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Plant Phenomics 2020年第1期2卷 367-377页

作者： Sam Sultan Joseph snider Adam Conn Mao Li Christopher N.Topp Saket Navlakha Cold Spring Harbor Laboratory Simons Center for Quantitative BiologyCold Spring HarborNYUSA University of California San Diego Institute for Neural ComputationLa JollaCAUSA Donald Danforth Plant Science Center St.LouisMOUSA

Numerous types of biological branching networks,with varying shapes and sizes,are used to acquire and distribute ***,we show that plant root and shoot architectures share a fundamental design *** studied the spatial density function of plant architectures,which specifies the probability of finding a branch at each location in the 3-dimensional volume occupied by the *** analyzed 1645 root architectures from four species and discovered that the spatial density functions of all architectures are *** means that despite their apparent visual diversity,all of the roots studied share the same basic shape,aside from stretching and compression along orthogonal ***,the spatial density of all architectures can be described as variations on a single underlying function:a Gaussian density truncated at a boundary of roughly three standard ***,the root density of any architecture requires only four parameters to specify:the total mass of the architecture and the standard deviations of the Gaussian in the threeðx,y,zÞgrowth *** shoot architectures also follow this design form,suggesting that two basic plant transport systems may use similar growth strategies.

关键词： networks Plant directions

Applying plant-based irrigation scheduling to assess water use efficiency of cotton following a high-biomass rye cover crop

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Journal of Cotton Research 2020年第2期3卷 134-145页

作者： MEEKS Calvin D snider John L CULPEPPER Stanley HAwKINS Gary Division of Plant Sciences University of MissouriPortagevilleMO 63873USA Department of Crop and Soil Sciences University of GeorgiaTiftonGA 31793USA Department of Crop and Soil Sciences University of GeorgiaWatkinsvilleGA 30677USA.

Background:This study addressed the potential of combining a high biomass rye winter cover crop with predawn leaf water potential(ΨPD)irrigation thresholds to increase agricultural water use efficiency(wUE)in *** this end,a study was conducted near Tifton,Georgia under a manually-controlled,variable-rate lateral irrigation system using a Scholander pressure chamber approach to measure leaf water potential and impose varying irrigation scheduling treatments during the growing season.ΨPDthresholds were-0.4 MPa(T1),-0.5 MPa(T2),and-0.7 MPa(T3).A winter rye cover crop or conventional tillage were utilized for T1-T3 as ***:Reductions in irrigation of up to 10%were noted in this study for the driest threshold(-0.7 MPa)with no reduction in lint yield relative to the-0.4 MPa and-0.5 MPa *** conditions during flowering(2014)limited plant growth and node production,hastened cutout,and decreased yield and wUE relative to ***:we conclude thatΨPDirrigation thresholds between-0.5 MPa and-0.7 MPa appear to be viable for use in aΨPDscheduling system with adequate yield and wUE for cotton production in the southeastern *** cover positively impacted water potential at certain points throughout the growing season but not yield or wUE indicating the potential for rye cover crops to improve water use efficiency should be tested under longer-term production scenarios.

关键词： Cotton Irrigation management water use efficiency Cover crops Cotton sustainability

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DTS中长距离输电线路的电磁暂态仿真

电网技术 2002年第7期26卷 7-10页

作者：戴仁昶 KevinK.w.Chan LaurenceA.snider 张伯明清华大学电机工程与应用电子技术系北京100084 香港理工大学电机工程系

提出了一种对高压交流长距离输电线路进行电磁暂态模拟的方法,并将其用于调度员培训仿真器(DTS)中。为保证DTS仿真的精度和速度,采用了对高压交流长距离均匀传输线采用电磁暂态模型、网络其他部分仍然采用常规机电暂态模型的混合暂态仿... 详细信息

提出了一种对高压交流长距离输电线路进行电磁暂态模拟的方法,并将其用于调度员培训仿真器(DTS)中。为保证DTS仿真的精度和速度,采用了对高压交流长距离均匀传输线采用电磁暂态模型、网络其他部分仍然采用常规机电暂态模型的混合暂态仿真方法。简单算例和实际算例结果证实了所提方法的正确性和有效性。

关键词： DTS 长距离输电线路电磁暂态仿真电力系统

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DTS中静止无功补偿器的电磁暂态仿真

电网技术 2002年第8期26卷 1-3页

作者：戴仁昶 KevinK.w.Chan LaurenceA.snider 张伯明清华大学电机工程与应用电子技术系北京100084 香港理工大学电机工程系

介绍了对静止无功补偿器的电磁暂态过程所进行的仿真,并将其嵌入调度员培训仿真器(DTS)中。为保证DTS仿真的精度和速度,采用对静止无功补偿器进行电磁暂态仿真,网络其他部分进行常规机电暂态仿真的综合暂态仿真方法,算例结果证实了静止... 详细信息

介绍了对静止无功补偿器的电磁暂态过程所进行的仿真,并将其嵌入调度员培训仿真器(DTS)中。为保证DTS仿真的精度和速度,采用对静止无功补偿器进行电磁暂态仿真,网络其他部分进行常规机电暂态仿真的综合暂态仿真方法,算例结果证实了静止无功补偿器可以有效地维持母线的电压水平提高系统的暂态稳定性。

关键词： DTS 静止无功补偿器电磁暂态仿真电力系统直流输电系统

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

^(99m)TC-Methylene diphosphonate uptake at injury site correlates with osteoblast differentiation and mineralization during bone healing in mice

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Bone Research 2015年第2期3卷 92-99页

作者： Zhendong A Zhong Anderson Peck Shihong Li Jeff Van Oss John snider Casey J Droscha Tingtung A Chang Bart O williams Center for Skeletal Disease Research Van Andel Research Institute Department of Internal Medicine Center for Musculoskeletal Health UC Davis Medical Center Small Animal Imaging Facility Van Andel Research Institute

99mTc-Methylene diphosphonate （99mTc-MDP） is widely used in clinical settings to detect bone abnormalities. However, the mechanism of 99mTc-MDP uptake in bone is not well elucidated. In this study, we utilized a mouse tibia injury model, single-photon emission computed tomography （gamma scintigraphy or SPECT）, ex vivo micro-computed tomography, and histology to monitor 99mTc-MDP uptake in injury sites during skeletal healing. In an ex vivo culture system, calvarial cells were differentiated into osteoblasts with osteogenic medium, pulsed with 99mTc-MDP at different time points, and quantitated for 99mTc-MDP uptake with a gamma counter. we demonstrated that 99mTc-MDP uptake in the injury sites corresponded to osteoblast generation in those sites throughout the healing process. The 99mTc-MDP uptake within the injury sites peaked on day 7 post-injury, while the injury sites were occupied by mature osteoblasts also starting from day 7. ~mTc-MDP uptake started to decrease 14 days post-surgery, when we observed the highest level of bony tissue in the injury sites. we also found that 99mTc-MDP uptake was associated with osteoblast maturation and mineralization in vitro. This study provides direct and biological evidence for 99mTc-MDP uptake in osteoblasts during bone healing in vivo and in vitro.

关键词： MDP bone TC-Methylene diphosphonate uptake at injury site correlates with osteoblast differentiation and mineralization during bone healing in mice SPECT

Towards estimating shade response of bermudagrass(Cynodon spp.)using field-based photosynthetic properties

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Grass Research 2022年第1期2卷 20-25,I0001-I0004页

作者： Jonathon L.Fox David Jespersen Lisa L.Baxter John L.snider Marc w.van Iersel Brian M.Schwartz Department of Crop and Soil Sciences University of Georgia2360 Rainwater Rd.TiftonGA 31794USA Department of Crop and Soil Sciences University of Georgia1109 Experiment St.GriffinGA 30223USA Department of Horticulture University of Georgia1111 Plant Science BuildingAthensGA 30602USA

Shade tolerance is a highly desirable trait when breeding new bermudagrass(Cynodon spp.)lines,but current screening methods can take many years to *** is a clear need for large-scale turfgrass breeding programs to reliably,accurately,and quickly predict shade tolerance in their *** objectives of this research were to:(i)build custom chambers to reproducibly estimate photosynthetic characteristics from turfgrass canopies at different light intensities and(ii)determine which photosynthetic characteristics are indicative of past shade performance.A custom-built chamber was constructed to determine average photosynthetic characteristics for the whole plant by studying the turfgrass canopy at natural leaf angles for light *** tolerant(11-T-56)and shade sensitive(Tifway)bermudagrass cultivars were used to examine the effectiveness of the chamber within an array of photosynthetic characteristics when the grasses were grown in full-sun and 73%shade *** compensation point,chlorophyll content,quantum yield,dark respiration rate,and maximum quantum yield of photosystem II were evaluated in this *** on the results of this study,the authors recommend that light compensation point or maximum quantum yield be further evaluated as an accurate indicator of shade tolerance when performed in the field on spring days with grasses grown in full sun or 73%shade *** Rd rates and ambient temperatures on spring days appear to minimize unexplained variance in the data,which would allow researchers to better detect genotypic differences during this season.

关键词： breeding field estimating