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On the Features of thermal Convection in a Compressible Gas

Fluid Dynamics & Materials Processing 2024年第5期20卷 957-974页

作者： Igor b.Palymskiy Physics Department Siberian State University of Telecommunications and Information SciencesNovosibirsk City630102Russia Physics Department Siberian State University of Geosystems and TechnologiesNovosibirsk City630108Russia

the fully nonlinear equations of gas dynamics are solved in the framework of a numerical approach in order to study the stability of the steady mode of Rayleigh-bénard convection in compressible,viscous and heat-conducting gases encapsulated in containers with no-slip boundaries and isothermal top and bottom *** initial linear temperature profile is assumed.A map of the possible convective modes is presented assuming the height of the region and the value of the temperature gradient as influential *** a relatively small height,isobaric convection is found to take place,which is taken over by an adiabatic mode when the height exceeds the critical value,or by a super-adiabatic mode in case of a relatively high temperature *** the adiabatic mode,convective flow develops due to adiabatic processes given a stable initial *** analytic formula for the critical height of the region is derived taking into account and neglecting the dependence of the gas viscosity on the ***,an analytic formula is obtained for the upper boundary of the region of applicability of the boussinesq approximation for incompressible *** models for compressible gases are relevant to practical situations such as the study of convective flows in spatially extended gas mixtures when dealing with safety issues related to hydrocarbons stored in gas stations.A dangerous situation arises when the tank is almost empty but some hydrocarbon is left at the bottom of the *** the presence of convective flows,the vaporized fuel is mixed with the oxidizer(air)forming a gas-vapor ***,if the volumetric concentration of fuel vapor(hydrocarbon)is in the interval between the lower and upper concentration limits of ignition,then the gas-vapor mixture becomes explosive and any accidental spark is sufficient to cause an emergency.

关键词： Rayleigh-bénard convection gas stable stratification unstable stratification temperature gradient

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Storylines of family medicine Ⅰ:framing family medicine–history,values and perspectives

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Family Medicine and Community Health 2024年第S3期12卷 2-11页

作者： William b Ventres Leslie A Stone Kathleen t Rowland Richard H Streiffer Michael D Macechko Julia A Roulier Jeffrey M borkan Larry A Green Family and Preventive Medicine University of Arkansas for Medical Sciences College of MedicineLittle RockArkansasUSA Family and Preventive Medicine Rush Medical College of Rush UniversityChicagoIllinoisUSA College of Community Health Sciences University of AlabamaTuscaloosaAlabamaUSA UAMS Northwest Regional Campus Family Medicine Residency Program FayettevilleArkansasUSA UAMS North Central Regional Campus Family Medicine Residency Program BatesvilleArkansasUSA Family Medicine Brown University Warren Alpert Medical SchoolProvidenceRhode IslandUSA University of Colorado School of Medicine AuroraColoradoUSA

Storylines of Family Medicine is a 12-part series of thematically linked mini-essays with accompanying illustrations that explore the many dimensions of family medicine,as interpreted by individual family physicians and medical educators in the USA and elsewhere around the ***‘Ⅰ:framing family medicine—history,values,and perspectives’,the authors address the following themes:‘Notes on Storylines of Family Medicine’,‘Family medicine—the generalist specialty’,‘Family medicine’s achievements—a glass half full assessment’,‘Family medicine’s next 50 years—toward filling our glasses’,‘Four enduring truths of family medicine’,‘Names matter’,‘Family medicine at its core’and‘the ecology of medical care.’May readers find much food for thought in these essays.

关键词： glasses illustration Notes

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Epidemiologic investigation of pediatric distal humerus fractures: An American insurance claims database study

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World Journal of Orthopedics 2024年第1期15卷 52-60页

作者： Kyle Jay Klahs Jake E Dertinger Grant t Mello Kevin thapa Alexis b Sandler E'Stephan J Jesus Garcia Nata Parnes Department of Orthopaedic Surgery Texas Tech University Health Sciences-El PasoEl PasoTX 79905United States Medical School California Health Sciences University College of Osteopathic MedicineClovisCA 93611United States Undergraduate School Binghampton UniversityVestalNY 13902United States Department of Orthopaedic Surgery William Beaumont Army Medical CenterFort BlissTX 79918United States Department of Orthopaedic Surgery Carthage Area HospitalCarthageNY 13619United States

bACKGROUND Distal humerus elbow fractures are one of the most common traumatic fractures seen in pediatric patients and present as three main types:Supracondylar(SC),lateral condyle(LC),and medial epicondyle(ME)*** to evaluate the epidemiology of pediatric distal humerus fractures(SC,LC,and ME)from an American insurance claims *** A retrospective review was performed on patients 17 years and younger with the ICD 9 and 10 codes for SC,LC and ME fractures based on the IbM truven MarketScan®Commercial and IbM truven MarketScan Medicare Supplemental *** from 2015 to 2020 were queried for treatments,patient age,sex,length of hospitalization,and *** A total of 1133 SC,154 LC,and 124 ME fractures were *** fractures had the highest percentage of operation at 83%,followed by LC(78%)and ME fractures(41%).Male patients were,on average,older than female patients for both SC and ME *** In the insurance claims databases used,SC fractures were the most reported,followed by LC fractures,and finally ME *** was identified to be a factor for how a pediatric distal humerus fractures,with patients with SC and LC fractures being younger than those with ME *** peak age per injury per sex was similar to reported historic central tendencies,despite reported trends for younger physiologic development.

关键词： Supracondylar humerus fracture Lateral condyle fracture Medial epicondyle fracture Pediatric elbow truven Epidemiology

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basis for the diversity and extent in loss of digestible nutrients created by dietary phytin: Emphasis on fowl and swine

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Animal Nutrition 2024年第1期16卷 422-428页

作者： Edwin t.Moran Michael R.bedford Poultry Science Department Auburn University Ab Vista Woodstock Court Blenheim Road

Phytin is the Ca2+-Mg2+-K+salt of phytic acid that is created and deposited in the aleurone layer and/or germ of grains and legumes. Its high presence in feedstuffs for fowl and swine diets results in it being a universal and significant impediment to optimum performance. Phytin impairs gastrointestinal recovery of a wide array of nutrients, the effect varying with the nutrient concerned. On exposure to low pH during gastric digestion, phytin dissociates into phytic acid and solubilized Ca2+. Even at low gastric pH,phytic acid is negatively charged which forms the basis of its anti-nutritive behavior. Pepsinogen has extensive basic amino acids on its activation peptide that are presented as cations at low pH which are targeted by pepsin for activation. Partially crystalized Ca2+near the enzyme?s active site further stabilizes its newly formed structure. thus, phytic acid appears to interfere with gastric digestion by several mechanisms; interfering with pepsinogen activation by binding to the polypeptide?s basic amino acids;coordinating free Ca2+, destabilizing pepsin; binding some dietary proteins directly, further compromising gastric proteolysis. Upon digesta attaining neutrality in the duodenum, Ca2+and other cations rebind with accessible anions, phytic acid being a significant contender. Phytate not only binds free cations but can also strip them from enzymes(e.g. Ca2+, Zn2+) which reduces their structural resistance to autolysis and ability as co-factors(e.g. Zn2+) to increase enzyme activity. Goblet cells initially employ Ca2+as an electronic shield between mucin layers enabling granule formation and cell storage. After mucin granule release, Ca2+is progressively displaced by Na+to free the viscous mucins enabling its translocation. Mucin entangles with the glycocalyx of adjacent enterocytes thereby constructing the unstirred water layer（USWL）. Excessive removal of Ca2+from mucin by phytic acid increases its fluidity facilitating its loss from the USWL with

关键词： Digestive enzyme Calcium Endogenous protein Mucin Phytin

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the bumpy road of purinergic inhibitors to clinical application in immune-mediated diseases

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Neural Regeneration Research 2024年第6期19卷 1206-1211页

作者： Matthias t.Wyss Christine Heuer Marina Herwerth Institute of Pharmacology and toxicology University of ZurichZürichSwitzerland Neuroscience Center Zurich(ZNZ) University of Zurich and ETH ZurichZürichSwitzerland Neurology Department University Hospital of ZurichZürichSwitzerland

Purinergic signaling plays important roles throughout the body in the regulation of organ functions during and following the disruption of *** is also reflected by the widespread expression of two families of purinergic receptors(P1 and P2)with numerous *** the last few decades,there has been increasing evidence that purinergic signaling plays an important role in the regulation of immune ***,signals mediated by P2 receptors have been shown to contribute to immune system-mediated ***,interference with P2 receptors may be a promising strategy for the modulation of immune *** only a few clinical studies have been conducted in isolated entities with limited success,preclinical work suggests that the use of P2 receptor inhibitors may bear some promise in various autoimmune *** the association of P2 receptors with several disorders from this field,the use of P2 receptor antagonists in clinical therapy is still very *** this narrative review,we briefly review the involvement of the purinergic system in immunological responses and clinical studies on the effect of purinergic inhibition on autoimmune *** then open the aperture a bit and show some preclinical studies demonstrating a potential effect of purinergic blockade on autoimmune *** suramin,a non-specific purinergic inhibitor,as an example,we further show that off-target effects could be responsible for observed effects in immunological settings,which may have interesting ***,we believe that it is worthwhile to further investigate this hitherto underexplored area.

关键词： autoimmune diseases neurological disorders purinergic system P2 receptor inhibitors suramin

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Nonlinear-Optical Analogies in Nuclear-Like Soliton Reactions:Selection Rules,Nonlinear tunneling and Sub-barrier Fusion–Fission

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Chinese Physics Letters 2024年第8期41卷 1-7页

作者： t.L.belyaeva V.N.Serkin Universidad Autonoma del Estado de Mexico Av.Instituto Literario 100C.P.50000TolucaMexico benemerita Universidad Autonoma de Puebla Av.4 Sur 104C.P.72001PueblaMexico

the main goal of our study is to reveal unexpected but intriguing analogies arising between optical solitons and nuclear physics,which still remain hidden from *** consider the main cornerstones of the concept of nonlinear optics of nuclear reactions and the well-dressed repulsive-core *** the base of this model,we reveal the most intriguing properties of the nonlinear tunneling of nucleus-like solitons and the soliton selfinduced sub-barrier transparency *** describe novel interesting and stimulating analogies between the interaction of nucleus-like solitons on the repulsive barrier and nuclear sub-barrier *** main finding of this study concerns the conservation of total number of nucleons(or the baryon number)in nuclear-like soliton *** show that inelastic interactions among well-dressed repulsive-core solitons arise only when a“cloud”of“dressing”spectral side-bands appears in the frequency spectra of the *** property of nucleus-like solitons is directly related to the nuclear density distribution described by the dimensionless small shape-squareness *** the Fourier spectra of nucleus-like solitons are similar to the nuclear form *** show that the nuclear-like reactions between well-dressed solitons are realized by“exchange”between“particle-like”side bands in their spectra.

关键词： solitons soliton Nonlinear

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Distribution, health and ecological risk assessments of trace elements in Nigerian oil sands

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Acta Geochimica 2024年第1期43卷 59-71页

作者： Odunayo t.Ore Festus M.Adebiyi Department of Chemistry Obafemi Awolowo UniversityIle-Ife 220005Nigeria Department of Chemical Sciences Achievers UniversityOwoNigeria

the Nigerian oil sands represent the largest oil sand deposit in Africa, yet there is little published information on the distribution and potential health and ecological risks of trace elements in the oil resource. In the present study, we investigated the distribution pattern of 18trace elements(including biophile and chalcophile elements) as well as the estimated risks associated with exposure to these elements. the results of the study indicated that Fe was the most abundant element, with a mean concentration of 22,131 mg/kg while br had the lowest mean concentration of 48 mg/kg. the high occurrence of Fe and ti suggested a possible occurrence of ilmenite(Fe tiO_(3)) in the oil sands. Source apportionment using positive matrix factorization showed that the possible sources of detected elements in the oil sands were geogenic, metal production, and crustal. the contamination factor, geo-accumulation index, modified degree of contamination, pollution load index, and Nemerow pollution index indicated that the oil sands are heavily polluted by the elements. Health risk assessment showed that children were relatively more susceptible to the potentially toxic elements in the oil sands principally via ingestion exposure route(HQ > 1E-04). Cancer risks from inhalation are unlikely due to CR but ingestion and dermal contact pose severe risks(CR > 1E-04). the high concentrations of the elements pose serious threats due to the potential for atmospheric transport, bioaccessibility, and bioavailability.

关键词： biophile Chalcophile Oil sand Risk assessment trace element

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Learning to become addicted,one synapse at a time

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Neural Regeneration Research 2024年第2期19卷 401-402页

作者： Alessio Attardo Sidney b.Cambridge Leibniz Institute for Neurobiology MagdeburgGermany Institute for Anatomy II Dr.Senckenberg AnatomyGoethe-University Frankfurt am MainFrankfurtGermany

Addiction has been extensively studied on many levels:from the molecular level,with various“omics”approaches(Natividad et al.,2018;Grecco et al.,2021),to the clinical level,with psychotherapy and MRI imaging(Ceceli ... 详细信息

关键词： clinical therapy

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Solvation Effects on the Dielectric Constant of 1 M LiPF6 in Ethylene Carbonate:Ethyl Methyl Carbonate 3:7

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Energy & Environmental Materials 2024年第1期7卷 253-256页

作者： Julian Self Nathan t.Hahn Kristin A.Persson Department of Chemical Engineering Polytechnique MontrealMontrealQC H3T 1J4Canada Department of Materials Science and Engineering University of CaliforniaBerkeleyCA 94720USA Energy technologies Area Lawrence Berkeley National LaboratoryBerkeleyCA 94720USA Material Physical and Chemical Sciences CenterSandia National LaboratoriesAlbuquerqueNM 87185USA

We report the dielectric constant of 1 M LiPF_(6)in EC:EMC 3∶7 w/w(ethylene carbonate/ethyl methyl carbonate)in addition to neat EC:EMC 3∶7 w/*** three Debye relaxations,the static permittivity value,or dielectric constant,is extrapolated to 18.5,which is compared to 18.7 for the neat solvent *** EC solvent is found to strongly coordinate with the Li^(+)cations of the salt,which results in a loss of dielectric contribution to the ***,the small amplitude and large uncertainty in relaxation frequency for EMC cloud definitive identification of the Li^(+)solvation ***,the loss of the free EC permittivity contribution due to Li^(+)solvation is almost completely balanced by the positive contribution of the associated LiPF_(6)salt,demonstrating that a significant quantity of dipolar ion pairs exists in 1 M LiPF_(6)in EC:EMC 3∶7.

关键词： batteries dielectric relaxation spectroscopy electrolytes

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Effects of layer interactions on instantaneous stability of finite Stokes flows

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Applied Mathematics and Mechanics(English Edition) 2024年第1期45卷 69-84页

作者： Chen ZHAO Zhenli CHEN C.t.MUtASA Dong LI School of Aeronautics Northwestern Polytechnical UniversityXi'an 710072China

the stability analysis of a finite Stokes layer is of practical importance in flow control. In the present work, the instantaneous stability of a finite Stokes layer with layer interactions is studied via a linear stability analysis of the frozen phases of the base flow. the oscillations of two plates can have different velocity amplitudes, initial phases, and frequencies. the effects of the Stokes-layer interactions on the stability when two plates oscillate synchronously are analyzed. the growth rates of two most unstable modes when δ t equal, and δ = δ*/h*, where δ*and h*are the Stokes-layer thickness and the half height of the channel, respectively. However, their vorticities are different. the vorticity of the most unstable mode is symmetric, while the other is asymmetric. the Stokes-layer interactions have a destabilizing effect on the most unstable mode when δ tabilizing effect when δ > 0.68. However, the interactions always have a stabilizing effect on the other unstable mode. It is explained that one of the two unstable modes has much higher dissipation than the other one when the Stokes-layer interactions are strong. We also find that the stability of the Stokes layer is closely related to the inflectional points of the base-flow velocity profile. the effects of inconsistent velocity-amplitude, initial phase, and frequency of the oscillations on the stability are analyzed. the energy of the most unstable eigenvector is mainly distributed near the plate of higher velocity amplitude or higher oscillation frequency. the effects of the initial phase difference are complicated because the base-flow velocity is extremely sensitive to the initial phase.

关键词： finite Stokes layer instantaneous stability Stokes-layer interaction asynchronous oscillation

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