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On the Navier-Stokes Equations for Exothermically reacting Compressible Fluids

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Acta Mathematicae Applicatae Sinica 2002年第1期18卷 15-36页

作者： david Hoff Konstantina Trivisa Department of Mathematics Indiana University BloomingtonIN 47405-4301USADepartment of Mathematics University of MarylandCollege Park MD 20742-4015USA

We analyze mathematical models governing planar flow of chemical reaction from unburnt gases to burnt gases in certain physical regimes in which diffusive effects such as viscosity and heat conduction are significant. These models can be then formulated as the Navier-Stokes equations for exothermically reacting compressible fluids. We first establish the existence and dynamic behavior, including stability, regularity, and large-time behavior, of global discontinuous solutions of large oscillation to the Navier-Stokes equations with constant adiabatic exponent γ and specific heat Cv. Our approach for the existence and regularity is to combine the difference approximation techniques with the energy methods, total variation estimates, and weak convergence arguments to deal with large jump discontinuities; and for large-time behavior is an a posteriori argument directly from the weak form of the equations. The approach and ideas we develop here can be applied to solving a more complicated model where γand cv vary as the phase changes; and we then describe this model in detail and contrast the results on the asymptotic behavior of the solutions of these two different models. We also discuss other physical models describing dynamic combustion.

关键词： Global discontinuous solutions discontinuous initial data large oscillation evolution of large jump discontinuities asymptotic behavior combustion Navier-Stokes equations difference approximations energy estimates total variation estim

Elucidating the impact of the ionomer equivalent weight on a platinum group metal-free PEMFC cathode via oxygen limiting current

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SusMat 2023年第1期3卷 72-90页

作者： HaoWang Luigi Osmieri Haoran Yu Michael J.Zachman Jae Hyung park Nancy N.Kariuki Firat C.Cetinbas Sunilkumar Khandavalli Scott Mauger Deborah J.Myers david A.Cullen Kenneth C.Neyerlin Chemistry and Nanoscience Center National Renewable Energy LaboratoryGoldenColoradoUSA Center for Nanophase Materials Sciences Oak Ridge National LaboratoryOak RidgeTennesseeUSA Chemical Sciences and Engineering Division Argonne National LaboratoryLemontIllinoisUSA Nuclear Science and Engineering Division Argonne National LaboratoryLemontIllinoisUSA

Leveraging the interactions between ionomer and catalyst can increase the performance of proton exchangemembrane fuel *** impacts of the equivalent weight(EW)of perfluorosulfonic acid-based ionomers on the platinum group metal-free electrode structure and fuel cell performance have not been fully *** membrane electrode assemblies(MEAs)were prepared by using a commercial Fe-N-C catalyst,two perfluorosulfonic acid ionomers with different EWs,that is,Aquivion 720(A720)and Nafion 1100(N1100),and two ionomer-tocatalyst(I/C)*** four MEAswere characterized to understand the impact of the ionomer EW and content on the capacitance,proton conductivity,and mass transport on the *** mass transport resistance was measured for the first time using a new oxygen reduction reaction limiting current method enabling to couple the effects of oxygen diffusion with liquid water *** EW ionomer combined with a moderate I/C results in improved performance due to its enhanced proton ***,when used at high I/C,it can cause severewater flooding at high current density due to the enhanced liquid water uptake,especially at high relative humidity,resulting in lower catalyst utilization and higher mass transport resistance.

关键词： ionomer equivalent weight limiting current mass transport oxygen reduction reaction PGMfree catalyst proton exchange membrane fuel cell

Suitability of the woodchuck HCC as a preclinical model for evaluation of intra-arterial therapies

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Animal Models and Experimental Medicine 2020年第1期3卷 98-102页

作者： Alexander Y.Kim Joseph H.Yacoub david H.Field Byoung Uk park Bhaskar Kallakury Kyle E.Korolowicz Stephan Menne Department of radiology Medstar Georgetown University HospitalWashingtonDistrict of Columbia Department of Pathology and Laboratory Medicine Medstar Georgetown University HospitalWashingtonDistrict of Columbia Department of Microbiology and Immunology Georgetown University Medical CenterWashingtonDistrict of Columbia

The most commonly used preclinical models of hepatocellular carcinoma(HCC)are limited for use in testing of intra-arterial therapies such as transarterial chemoembolization and *** encountered with the more commonly used animal models include dissimilarity in their disease development compared with humans and the size of the vasculature which can make intra-arterial therapy testing difficult or *** we describe the suitability of the woodchuck HCC model for testing of intra-arterial *** describe the techniques for pre-embolization imaging assessment using CT and MrI,technical tips on performing angiography and embolization,and pathological assessment of treated liver.

关键词： angiography animal model hepatocellular carcinoma woodchuck

Axial strain enhances osteotomy repair with a concomitant increase in connexin43 expression

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Bone research 2015年第2期3卷 83-91页

作者： rishi r Gupta Hyunchul Kim Yu-Kwan Chan Carla Hebert Leah Gitajn david J Yoo robert V O’Toole Adam H Hsieh Joseph P Stains Department of Orthopaedics University of Maryland Fischell Department of Bioengineering University of MarylandCollege Park

The mechanical environment is known to influence fracture healing. We speculated that connexin43 （Cx43） gap junctions, which impact skeletal homeostasis, fracture healing and the osteogenic response to mechanical load, may play a role in mediating the response of the healing bone to mechanical strain. Here, we used an established rat fracture model, which uses a 2 mm osteotomy gap stabilized by an external fixator, to examine the impact of various cyclical axial loading protocols （2%, 10%, and 30% strain） on osteotomy healing. We examined the presence of Cx43 in the osteotomy-healing environment and assessed how mechanical strain modulates Cx43 expression patterns in the callus. We demonstrated that increased cyclical axial strain results in increased radiographic and histologic bone formation. In addition, we show by immunohistochemistry that Cx43 is abundantly expressed in the healing callus, with the expression most robust in samples exposed to increased cyclical axial strain. These data are consistent with the concept that an increase in Cx43 expression by mechanical load may be part of the mechanisms by which mechanical forces enhances fracture healing.

关键词： connexin healing repair concomitant callus homeostasis assessed skeletal exposed stained

Data Center Power System Stability-Part II: System Modeling and Analysis

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CSEE Journal of Power and Energy Systems 2022年第2期8卷 420-438页

作者： Jian Sun Melaku Mihret Mauricio Cespedes david Wong Mike Kauffman rensselaer Polytechnic Institute-ECSE 1108th Street Room CII 8015Troy 12180United States Meta Platforms Inc. 1601 Willow RdMenlo ParkCalifornia 94025-1452United States

This is the second part of a two-part paper on stability study of data center power systems by impedance-based *** the basis for this application,Part I[1]developed new impedance models for power supplies that are the most dominant loads in data *** second part presents system modeling and analysis methods that can support practical data center power system design to ensure *** proposed methods comprise:1)building distribution network modeling by impedance scaling;2)system modeling and model reduction based on equivalent source impedance;3)system stability analysis in the sequence domain to include zero-sequence dynamics;and 4)expansion of system models and analyses to account for network asymmetry and uneven *** methods are used to characterize practical resonance problems observed in data centers,explain their root causes,and develop *** systems using Y-connected power supply units(PSUs),the zero sequence is identified as the weakest link and the first to become *** expanded system model and analysis reveal a new,differential-mode instability that is responsible for high frequency *** guarantee system stability,new impedance-based product and system design specifications are developed based on sufficient conditions derived from the Nyquist stability *** and field measurements are presented to substantiate the proposed methods and conclusions.

关键词： Data center power systems frequency-domain methods impedance modeling system stability system resonance

rANKL-responsive epigenetic mechanism reprograms macrophages into bone-resorbing osteoclasts

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Cellular & Molecular Immunology 2023年第1期20卷 94-109页

作者： Seyeon Bae Kibyeong Kim Keunsoo Kang Haemin Kim Minjoon Lee Brian Oh Kaichi Kaneko Sungkook Ma Jae Hoon Choi Hojoong Kwak Eun Young Lee Sung Ho park Kyung-Hyun park-Min Arthritis and Tissue Degeneration Program David Z.Rosensweig Genomics Research CenterHospital for Special SurgeryNew YorkNY10021USA Department of Medicine Weill Cornell Medical CollegeNew YorkNY10065USA Department of Biological Science Ulsan National Institute of Science&Technology(UNIST)Ulsan44919Republic of Korea Department of Life Science College of Natural SciencesResearch Institute for Natural SciencesHanyang UniversitySeoulKorea Department of Microbiology Dankook UniversityCheonan3116Republic of Korea Department of Molecular Biology and Genetics Cornell UniversityIthacaUSA Division of rheumatology Department of Internal MedicineSeoul National University College of MedicineSeoulKorea BCMB Allied Program Weill Cornell Graduate School of Medical SciencesNew YorkNY10021USA

Monocyte/macrophage lineage cells are highly plastic and can differentiate into various cells under different environmental stimuli. Bone-resorbing osteoclasts are derived from the monocyte/macrophage lineage in response to receptor activator of NF-κB ligand (rANKL). However, the epigenetic signature contributing to the fate commitment of monocyte/macrophage lineage differentiation into human osteoclasts is largely unknown. In this study, we identified rANKL-responsive human osteoclast-specific superenhancers (SEs) and SE-associated enhancer rNAs (SE-erNAs) by integrating data obtained from ChIP-seq, ATAC-seq, nuclear rNA-seq and PrO-seq analyses. rANKL induced the formation of 200 SEs, which are large clusters of enhancers, while suppressing 148 SEs in macrophages. rANKL-responsive SEs were strongly correlated with genes in the osteoclastogenic program and were selectively increased in human osteoclasts but marginally presented in osteoblasts, CD4+ T cells, and CD34+ cells. In addition to the major transcription factors identified in osteoclasts, we found that BATF binding motifs were highly enriched in rANKL-responsive SEs. The depletion of BATF1/3 inhibited rANKL-induced osteoclast differentiation. Furthermore, we found increased chromatin accessibility in SE regions, where rNA polymerase II was significantly recruited to induce the extragenic transcription of SE-erNAs, in human osteoclasts. Knocking down SE-erNAs in the vicinity of the NFATc1 gene diminished the expression of NFATc1, a major regulator of osteoclasts, and osteoclast differentiation. Inhibiting BET proteins suppressed the formation of some rANKL-responsive SEs and NFATc1-associated SEs, and the expression of SE-erNA:NFATc1. Moreover, SE-erNA:NFATc1 was highly expressed in the synovial macrophages of rheumatoid arthritis patients exhibiting high-osteoclastogenic potential. Our genome-wide analysis revealed rANKL-inducible SEs and SE-erNAs as osteoclast-specific signatures, which may contribute to t

关键词： Osteoclasts super-enhancers enhancer rNAs rheumatoid arthritis

Karrikin and Cyanohydrin Smoke Signals Provide Clues to New Endogenous Plant Signaling Compounds

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Molecular Plant 2013年第1期6卷 29-37页

作者： Gavin r. Flematti Mark T. Waters Adrian Scaffidi david J. Merritt Emilio L. Ghisalberti' Kingsley W.Dixon Steven M. Smith School of Chemistry and Biochemistry University of Western Australia Crawley 6009 Western Australia Australia Centre in Plant Energy Biology University of Western Australia Crawley 6009 Western Australia Australia School of Plant Biology University of Western Australia Crawley 6009 Western Australia Australia Kings park and Botanic Garden Fraser Avenue West Perth 6005 Western Australia Australia

Two new types of signaling compounds have been discovered in wildfire smoke due to their ability to stimulate seed germination. The first discovered were karrikins, which share some structural similarity with the strigol- actone class of plant hormones, and both signal through a common F-box protein. However, karrikins and strigolactones operate through otherwise distinct signaling pathways, each distinguished by a specific a/13 hydrolase protein. Genetic analysis suggests that plants contain endogenous compounds that signal specifically through the karrikin pathway. The other active compounds discovered in smoke are cyanohydrins that release germination-stimulating cyanide upon hydrolysis. Cyanohydrins occur widely in plants and have a role in defense against other organisms, but an additional role in endogenous cyanide signaling should also now be considered.

关键词： fire smoke karrikins strigolactones cyanohydrins cyanide seed germination Arabidopsis thaliana.

Defence force activities in marine protected areas:environmental management of Shoalwater Bay Training Area,Queensland,Australia

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Chinese Journal of Oceanology and Limnology 2010年第3期28卷 667-676页

作者：武文王小华 david PAULL Julie KESBY School of Physical Environmental and Mathematical Sciences University of New South Wales at Australian Defence Force Academy College of Physical and Environmental Oceanography Ocean University of China

Environmental management of military activities is of growing global concern by defence forces. As one of the largest landholders in Australia, the Australian Defence Force （ADF） is increasingly concerned with sustainable environmental management. This paper focuses on how the ADF is maintaining effective environmental management, especially in environmentally sensitive marine protected areas. It uses Shoalwater Bay Training Area （SWBTA） as a research example to examine environmental management strategies conducted by the ADF. SWBTA is one of the most significant Defence training areas in Australia, with a large number of single, joint and combined military exercises conducted in the area. With its maritime component contained in the Great Barrier reef Marine park （GBrMP）, the Great Barrier reef World Heritage Area （GBrWHA）, and abutting Queensland＇s State Marine parks, it has high protection values. It is therefore vital for the ADF to adopt environmentally responsible management while they are conducting military activities. As to various tools employed to manage environmental performance, the ISO 14001 Environmental Management System （EMS） is widely used by the ADE This paper exanlines military activities and marine environmental management within SWBTA, using the Talisman Saber （TS） exercise series as an example. These are extensive joint exercises conducted by the ADF and the United States defence forces. The paper outlines relevant legislative framework and environmental policies, analyses how the EMS operates in environmental management of military activities, and how military activities comply with these regulations. It discusses the implementation of the ADF EMS, including risk reduction measures, environmental awareness training, consultation and communication with stakeholders. A number of environmental management actions used in the TS exercises are presented to demonstrate the EMS application. Our investigations to this point indicate that the ADF is co

关键词： Australian Defence Force marine protected areas Environmental Management System Shoalwater Bay Training Area

The biogeography of group sizes in humpback dolphins(Sousa spp.)

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Integrative Zoology 2021年第4期16卷 527-537页

作者： Mingming LIU Mingli LIN david LUSSEAU Songhai LI Marine Mammal and Marine Bioacoustics Laboratory Institute of Deep-sea Science and EngineeringChinese Academy of SciencesSanyaChina University of Chinese Academy of Sciences BeijingChina School of Biological Sciences University of AberdeenAberdeenUK National Institute of Aquatic resources Technical University of DenmarkLyngbyDenmark Tropical Marine Science Institute National University of SingaporeSingapore

Humpback dolphins(Sousa spp.)are obligate shallow-water and resident species,and they typically live in fission–fusion societies composed of small-sized groups with changeable ***,we have scant knowledge of their behavioral ecology,starting with potential factors influencing inter-population variability of their group ***,we compiled a new global dataset of humpback dolphin group sizes based on 150 published *** data indicated an inter-specific consistency of group-living strategy among the 4 species in the Sousa genus,as these species preferred living in small-sized groups with a mean size of mostly no more than 10,a minimum size of single individual or small pairs,and a maximum size of several tens or≈*** addition,we clearly showed the geographic variations in group sizes of humpback dolphins at a global *** found that the geographic variations in humpback dolphin group sizes were primarily associated with the latitude,sea surface temperature,and *** conclude,our findings provide insights into social dynamics and socioecological trade-offs of humpback dolphins,and help better understand how these resident animals adapted to their shallow-water habitats from the perspectives of biogeography and socioecology.

关键词： biogeography geographic variations group size habitat humpback dolphins social dynamics socioecology