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Effects of second diffusing component and cross diffusion on primary and secondary thermoconvective instabilities in couple stress liquids

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Applied Mathematics and Mechanics(English Edition) 2017年第11期38卷 1579-1600页

作者： r.rAVI c.KANcHANA P.G.SIDDHESHWAr Department of Humanities and Sciences National Institute of Technology GoaGoa 403401India Department of Mathematics Jnana Bharathi CampusBangalore UniversityBangalore 560056India

Linear and weakly nonlinear analyses are made for the rayleigh-Benard convection in two-component couple-stress liquids with the Soret effect. conditions for pitchfork, Hopf, Takens-Bogdanov, and codimension-two bifurcations are presented. The Lorenz model is used to study the inverted bifurcation. Positive values of the Soret coefficient favor a pitchfork bifurcation, whereas negative values favor a Hopf bifurcation. Takens-Bogdanov and codimension-two bifurcations are not as much influenced by the Soret coefficient as pitchfork and Hopf bifurcations. The influence of the Soret coefficient on the inverted bifurcation is similar to the influence on the pitchfork bifurcation. The in- fluence of other parameters on the aforementioned bifurcations is also similar as reported earlier in the literature. Using the Newell-Whitehead-Segel equation, the condition for occurrence of Eckhaus and zigzag secondary instabilities is obtained. The domain of ap- pearance of Eckhaus and zigzag instabilities expands due to the presence of the Soret coefficient for positive values. The Soret coefficient with negative values enhances heat transport, while positive values diminish it in comparison with heat transport for the case without the Soret effect. The dual nature of other parameters in influencing heat and mass transport is shown by considering positive and negative values of the Soret coefficient.

关键词： codimension-two Eckhaus inverted Lorenz Newell-Whitehead-Segel,Nusselt number rayleigh-B^nard secondary instability Sherwood number Takens-Bogdanov zigzag

Inflammasome links traumatic brain injury, chronic traumatic encephalopathy, and Alzheimer's disease

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Neural regeneration research 2025年第6期20卷 1644-1664页

作者： Gabriela Seplovich Yazan Bouchi Juan Pablo de rivero Va.c.r. Jennifer c.Munoz Pareja Andrew reisner Laura Blackwell Yehia Mechref Kevin K.Wang J.Adrian Tyndall Binu Tharakan Firas Kobeissy Department of Surgery Morehouse School of MedicineAtlantaGAUSA Department of Neurobiology Center for NeurotraumaMultiomics&Biomarkers(CNMB)Neuroscience InstituteMorehouse School of MedicineAtlantaGAUSA Department of Neurological Surgery and the Miami Project to cure Paralysis University of Miami Miller School of MedicineMiamiFLUSA Division of Pediatric critical care Department of PediatricsUniversity of Miami Miller School of MedicineMiamiFLUSA Department of Pediatrics Emory UniversityAtlantaGAUSA Department of Neurosurgery Children’s Healthcare of AtlantaAtlantaGAUSA Department of chemistry and Biochemistry Texas Tech UniversityLubbockTXUSA Morehouse School of Medicine AtlantaGAUSA

Traumatic brain injury, chronic traumatic encephalopathy, and Alzheimer's disease are three distinct neurological disorders that share common pathophysiological mechanisms involving neuroinflammation. One sequela of neuroinflammation includes the pathologic hyperphosphorylation of tau protein, an endogenous microtubule-associated protein that protects the integrity of neuronal cytoskeletons. Tau hyperphosphorylation results in protein misfolding and subsequent accumulation of tau tangles forming neurotoxic aggregates. These misfolded proteins are characteristic of traumatic brain injury, chronic traumatic encephalopathy, and Alzheimer's disease and can lead to downstream neuroinflammatory processes, including assembly and activation of the inflammasome complex. Inflammasomes refer to a family of multimeric protein units that, upon activation, release a cascade of signaling molecules resulting in caspase-induced cell death and inflammation mediated by the release of interleukin-1β cytokine. One specific inflammasome, the NOD-like receptor protein 3, has been proposed to be a key regulator of tau phosphorylation where it has been shown that prolonged NOD-like receptor protein 3 activation acts as a causal factor in pathological tau accumulation and spreading. This review begins by describing the epidemiology and pathophysiology of traumatic brain injury, chronic traumatic encephalopathy, and Alzheimer's disease. Next, we highlight neuroinflammation as an overriding theme and discuss the role of the NOD-like receptor protein 3 inflammasome in the formation of tau deposits and how such tauopathic entities spread throughout the brain. We then propose a novel framework linking traumatic brain injury, chronic traumatic encephalopathy, and Alzheimer's disease as inflammasomedependent pathologies that exist along a temporal continuum. Finally, we discuss potential therapeutic targets that may intercept this pathway and ultimately minimize long-term neurological decline.

关键词： Alzheimer's disease caspase-1 chronic traumatic encephalopathy inflammasomes neurodegeneration neuroinflammation NLrP1 NLrP3 pyroptosis tauopathy traumatic brain injury

corrosion behavior of hypoeutectic Al-cu alloys in H_2SO_4 and Nacl solutions

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Acta Metallurgica Sinica(English Letters) 2009年第4期22卷 241-246页

作者： Wislei r.Osório Leandro c.Peixoto Leonardo r.Garcia Amauri Garcia Department of Materials Engineering University of Campinas-UNICAMP

The aim of this work was to evaluate the electrochemical behaviour of hypoeutectic Al-cu alloys immersed in two different solutions containing sulphate and chloride ions, respectively. The influence of Al2cu associated to the dendritic arm spacing on the general corrosion resistance of such alloys is analysed. The typical microstructural pattern was examined by using scanning electron microscope. The corrosion tests were performed in both 0.5 M sulphuric acid and 0.5 M Nacl solutions at 25℃ by using an electrochemical impedance spectroscopy （EIS） technique and potentiodynamic polarization curves. Equivalent circuits by using the ZView software, were also used to provide quantitative support for the discussions. It was found that as the cu content increased （i.e., increasing the Al2cu fraction）, a higher susceptibility to the corrosion action in the Nacl solution is detected. In contrast, the tests carried out in the H2SO4 solution resulted in similar corrosion,rates for the three different hypoeutectic alloys.

关键词： Al-cu alloys Al2cu corrosion Microstructure castings

MHD flow of a visco-elastic fluid through a porous medium between infinite parallel plates with time dependent suction

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Journal of Hydrodynamics 2015年第5期27卷 738-747页

作者： BAAG S. AcHArYA M.r. DASH G.c. MISHrA S.r. Department of Physics College of Basic Science and HumanitiesOUAT Department of Mathematics ITER SOA University

This work provides a comprehensive theoretical analysis of MHD unsteady free convection viscoelastic fluid flow through a porous medium. The medium is treated as incompressible and optically transparent. The flow of the fluid is initiated by shearing action of the moving wall with time dependent suction. radiative heat flow is considered in temperature equation. The coupled nonlinear problem has been solved asymptotically. Approximate solutions have been obtained for the mean velocity, mean temperature using multi parameter perturbation technique. The originality of the present study is to investigate the effect of viscoelastic property of the fluid（Walters B？ model） on the flow and heat transfer phenomena when the flow is permeated through a porous medium with uniform porous matrix subject to transverse magnetic field and time dependent fluctuative suction at the boundary surface. The case of viscous flow has been discussed as a particular case on comparison with the result reported earlier and it is in good agreement. Flow reversal is indicated incase of viscoelastic fluid with high heat capacity in the presence of magnetic field. The higher cooling of the plate in case of viscoelastic flow also causes a flow reversal.

关键词： viscoelastic liquid porosity radiation parameter time dependent suction

Influence of Heat Treatment on the Bond coat cyclic Oxidation Behaviour in an Air-plasma-sprayed Thermal Barrier coating System

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材料热处理学报 2004年第05B期25卷 923-929页

作者： W.r.chen X.Wu B.r.Marple P.c.Patnaik Structures MaterialsandPropulsionLaboratoryInstituteforAerospaceResearchNationalResearchCouncilCanadaOttawaOntarioCanadaK1AOR6 IndustrialMaterialsInstitute NationalResearchCouncilCanadaBouchervilleQuebecCanadaJ4B6Y4

It is generally believed that a thermally grown oxide (TOO) layer of alumina provides enhanced protection to the metallic bond coat in thermal barrier coating (TBc) systems at elevated temperatures. However, in an air-plasma-sprayed (APS) TBc system with co-32Ni-21cr-8Al-0.5Y (wt%) bond coat, the TGO layer formed upon thermal exposure in air was predominantly chromia and spinels, which would not effectively protect the bond coat at above 1000°c. In addition, mixed oxides of chromia, spinel and nickel oxide formed heterogeneously between the ceramic coating and coNicrAlY bond coat, which would promote crack initiation and lead to premature TBc failure. A heat treatment in a low-pressure condition was applied to the as-sprayed TBc system, with the aim to produce an alumina layer as well as reduce the amount of detrimental oxides. The influence of this low-pressure oxidation treatment (LPOT) on the bond coat cyclic oxidation behaviour of the TBc system was also investigated.

关键词：热处理 TGO TBc 低压氧化周期性氧化 coNicrAlY合金

Protozoan colonization on artificial substrates in relation to water quality in a tropical Indian harbour

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Journal of Environmental Sciences 2001年第2期13卷 143-147页

作者： V.r.Bharati r.N.Khan c.Kalavati A.V.raman Department of Zoology Andhra UniversityVisakhapatnam 530003India.

A field study was conducted to evaluate the protozoan colonization patterns on artificial substrates in relation to organic pollution within a tropical harbour. The composition of protozoans and their succession rates on artificial substrates(polyurethane foam units) were compared between two field stations(A and B), and their presence were considered with regards to the prevailing water quality conditions at the study sites. Altogether 44 genera of flagellates and ciliates were documented. The common genera of flagellates encountered included Monas, Polytoma, and chromalina. Among the ciliates, the predominant genera were Tetrahymena, Vorticella, Lagynophyra, and Heloiphyra. These groups exhibited characteristic successional patterns in relation to ambient water quality. At Station A, located close to the sewage outfall, the water quality parameters included poor Secchi disc transparency(0.48m), dissolved oxygen of 1.93 mg/ml, salinity of 18 psu, and temperature 31.3 ℃. Here, the nanoflagellates( spumella ) colonized first, followed by microcilliate( Tetrahymena ) and sessile form( Vorticella ). Station B, located on the seaward side, was characterized by relatively less stressed environmental conditions with transparency 1.85m and dissolved oxygen value of 6 04 mg/ml. Salinity of 27.27 psu, and mean temperature of 30 ℃ were recorded at “B'. At this station, the nanoflagellate Polytoma was first documented to colonize on the substrates, followed by microcilliate( Lagynophrya ) and suctorid( Heliophyra ). These findings support the use of protozoans as indicator species for evaluating the hazards posed by organic pollution to natural estuarine communities.

关键词： Protozoan colonization on artificial substrates in relation to water quality in a tropical Indian harbour

Antimicrobial activity of cotton and silk fabric with herbal extract by micro encapsulation

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Asian Pacific Journal of Tropical Medicine 2010年第2期3卷 128-132页

作者： Saraswathi r Krishnan PN Dilip c Al Shifa college of Pharmacy KizhatturPerinthalmannaKerala679325India

Objective:To explore the antimicrobial activity of microcapsules encapsulated with mixture of herbs like neem,tulsi and turmeric,and its application on cellulosic fabric in the form of ***:The microcapsules were prepared from the mixture of herbs by plain diffusion method,a natural encapsulation technique with yeast and applied on cotton and silk fabric by pad-dry-cure *** microcapsules were fixed on cotton and silk fabric using the binder UF Silpure FBr-5(PA)B at 120℃.The antimicrobial activities of the finished fabric were assessed by using three types of bacteria including Staphylococcus aureus,Escherichia coli and ***:The results of antimicrobial activity from the tests including parallel streak method and disc diffusion method showed that activity of the mixture of herbs was very effective among the three types of bacteria selected,and the antimicrobial activity of prepared microcapsule against Pseudomonas was very ***:The herbal microcapsule treated fabric could be applied in the field of *** scanning electron microscope photographs ensure the fixing of the microcapsules firmly in the yarn structure of plain woven cotton and silk fabric.

关键词： Antimicrobial activity Herbs microencapsulation Ultra-fresh silpure

Investigating the use of an ionic liquid for rare earth mineral flotation

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Journal of rare Earths 2021年第7期39卷 866-874,I0004页

作者： r.Li c.Marion E.r.L.Espirtu r.Multani Xiaoqi Sun K.E.Waters Department of Mining and Materials Engineering McGill University3610 Rue University.MontrealQuebecH3A 0C5Canada Vale Ontario Operations(Base Metals)18 Rink St.Copper CliffOntario POM 1N0Canada Fujian Institute of research on the Structure of Matter Chinese Academy of Sciences155 Yangqiao Road WestFuzhou 350002China

common collectors for rare earth mineral(rEM) flotation,which include carboxylates and hydroxamates,face problems such as being non-selective and sensitive to impurity ions.A type of ionic liquid(IL),tetraethylammonium mono-(2-ethylhexyl)2-ethylhexyl phosphonate([N_(2222)][EHEHP]),has been investigated previously for rare earth elements(rEE) solvent extraction,and was proven to be selective and *** this work,[N_(2222)][EHEHP] was evaluated as a collector in bastnasite(a primary rEM source for rEE production) flotation for the first *** results were compared with quartz and hematite,two common gangue minerals in rEM *** potential measurements and Fouriertransform infrared spectroscopy(FT-Ir) were completed to investigate the surface chemical properties involved in the flotation of these minerals using this *** findings were compared with microflotation ***-Ir and zeta potential measurements suggest adsorption of the collector’s phosphonate group onto bastnäsite and hematite,likely through chemisorption;whereas for quartz,the minimum micro flotation recovery is likely due to no adsorption of IL on its *** flotation re sults show higher collectability of [N_(2222)] [EHEHP] for hematite than bastnasite,the latter only shows appreciable recovery at pH 5 with elevated dosage of IL(500 g/t).To achieve better separation,a two-stage flotation scheme was designed and evaluated by bench scale flotation on a synthetic mineral *** concentrates and tails were analyzed by magnetic separation,and it is found that bastnasite recovery over 90% with maximum upgrade ratio 1.7 can be achieved with elevated collector dosage.

关键词： Ionic liquid rare earth Bastnasite Flotation FT-Ir Zeta potential

Microstructural Evolution of Infrared Brazed cP-Ti Using Ti-cu-Ni Brazes

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Journal of Materials Science & Technology 2011年第2期27卷 131-138页

作者： c.T.chang T.Y.Yeh r.K.Shiue c.S.chang Department of Mechanical Engineering National Hualien Industrial Vocational Senior High SchoolHualien 970TaiwanChina Department of Materials Science and Engineering National Taiwan UniversityTaipei 106TaiwanChina Engineered Materials Solutions 39 Perry AvenueMS 4-1AttleboroMA 02703-2410USA

Microstructural evolution of infrared vacuum brazed cP-Ti using two Ti-based braze alloys,Ti-15cu-15Ni and Ti-15cu-25Ni,has been *** infrared brazed joint consisted of eutectic Ti 2 cu/Ti 2 Ni intermetallic compounds and Ti-rich *** eutectic Ti 2 cu/Ti 2 Ni intermetallic compounds disappeared from the joint after being annealed at 900 c for 1 *** contrast,the depletion rate of both cu and Ni from the braze alloy into cP-Ti substrate at 750 c annealing was greatly decreased as compared with that annealed at 900 *** Ti 2 cu/Ti 2 Ni phases were observed even if the specimen was annealed at 750 c for 15 *** the Ni content of the Ti-15cu-25Ni braze alloy is much higher than that of the Ti-15cu-15Ni alloy,the amount of eutectic Ti 2 cu/Ti 2 Ni phases in Ti-15cu-25Ni brazed joint is more than that in Ti-15ci-15Ni brazed ***,similar microstructural evolution can be obtained from the infrared brazed joint annealed at various temperatures and/or time for both filler metals.

关键词： Infrared Brazing cP-Ti Ti-cu-Ni fillers Microstructure