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Acute and chronic excitotoxicity in ischemic stroke and late-onset Alzheimer's disease

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Neural Regeneration Research 2025年第7期20卷 1981-1988页

作者： shan Ping Yu Emily Choi Michael qJiang Ling Wei Department of Anesthesiology Emory University School of MedicineAtlantaGAUSA Center for Visual and Neurocognitive Rehabilitation Atlanta Veterans Affairs Medical CenterDecaturGAUSA

stroke and Alzheimer's disease are common neurological disorders and often occur in the same *** comorbidity of the two neurological disorders represents a grave health threat to older *** review presents a brief background of the development of novel concepts and their clinical *** activity of glutamatergic N-methyl-D-aspartate receptors and N-methyl-D-aspartate receptor-mediated Ca^(2+)influx is critical for neuronal *** ischemic insult induces prompt and excessive glutamate release and drastic increases of intracellular Ca^(2+)mainly via N-methyl-D-aspartate receptors,particularly of those at the extrasynaptic *** Ca^(2+)-evoked neuronal cell death in the ischemic core is dominated by necrosis within a few hours and days known as acute ***,mild but sustained Ca^(2+)increases under neurodegenerative conditions such as in the distant penumbra of the ischemic brain and early stages of Alzheimer's disease are not immediately toxic,but gradually set off deteriorating Ca^(2+)-dependent signals and neuronal cell loss mostly because of activation of programmed cell death *** on the Ca^(2+)hypothesis of Alzheimer's disease and recent advances,this Ca^(2+)-activated“silent”degenerative excitotoxicity evolves from years to decades and is recognized as a unique slow and chronic *** N-methyl-D-aspartate receptor subunit GluN3A,primarily at the extrasynaptic site,serves as a gatekeeper for the N-methyl-D-aspartate receptor activity and is neuroprotective against both acute and chronic *** stroke and Alzheimer's disease,therefore,share an N-methyl-D-aspartate receptor-and Ca^(2+)-mediated mechanism,although with much different time *** is thus proposed that early interventions to control Ca^(2+)homeostasis at the preclinical stage are pivotal for individuals who are susceptible to sporadic late-onset Alzheimer's disease and Alzheimer's disease-related

关键词： Ca^(2+)hypothesis cognitive deficits hyperactivity late-onset Alzheimer's disease neurodegeneration N-methyl-D-aspartate receptors N-methyl-D-aspartate receptor subunits pathogenesis preventive treatment

Tuning the microstructure for superb corrosion resistance in eutectic high entropy alloy

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Journal of Materials science & Technology 2022年第14期109卷 197-208页

作者： s.shuang q.Yua X.Gao q.F.He J.Y.Zhang s.q.shi Y.Yang Department of Mechanical Engineering City University of Hong KongKowloon TongKowloonHong KongChina Department of Mechanical Engineering Hong Kong Polytechnic UniversityHung HomKowloonHong KongChina Department of Materials science and Engineering City University of Hong KongKowloon TongKowloonHong KongChina

In this work,we demonstrate that the corrosion resistance of the FeCrNiCoNb_(0.5) eutectic high entropy alloy(EHEA)can be tuned by controlling the size of its eutectic *** microstructure refinement,the EHEA exhibits a superb corrosion resistance in 1 M NaCl in terms of a very low corrosion current density and an ultra-high transpassviation potential,which outperforms a variety of other HEAs and conventional metals and *** the fundamental level,the microstructure refinement results in a rapid formation of a thick and compact passive film with less Cl-adsorption on the EHEA,which results in significant enhancement in its corrosion *** outcome of our research provides important insights into the design of corrosion resistant chemically complex alloys.

关键词： Eutectic high entropy alloy Passivation Transpassivation potential Microstructure size

Deformation behavior of laser bending of circular sheet metal

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Chinese Optics Letters 2011年第5期9卷 47-51页

作者： q.Nadeem s.J.Na Department of Mechanical Engineering KAIST

The application of a thermal source in non-contact forming of sheet metal has long been used. However, the replacement of this thermal source with a laser beam promises much greater controllability of the process. This yields a process with strong potential for application in aerospace, shipbuilding, automobile, and manufacturing industries, as well as the rapid manufacturing of prototypes and adjustment of misaligned components. Forming is made possible through laser-induced non-uniform thermal stresses. In this letter, we use the geometrical transition from rectangular to circle-shaped specimen and ring-shaped specimen to observe the effect of geometry on deformation in laser forming. We conduct a series of experiments on a wide range of specimen geometries. The reasons for this behavior are also analyzed. Experimental results are compared with simulated values using the software ABAqUs. The utilization of line energy is found to be higher in the case of laser forming along linear irradiation than along curved ones. We also analyze the effect of strain hindrance. The findings of the study may be useful for the inverse problem, which involves acquiring the process parameters for a known target shape of a wide range of complex shape geometries.

关键词： Deformation behavior of laser bending of circular sheet metal

Axisymmetric wetting of a liquid droplet on a stretched elastic membrane

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Applied Mathematics and Mechanics(English Edition) 2023年第6期44卷 997-1006页

作者： C.q.RU Department of Mechanical Engineering University of AlbertaEdmontonAB T6G 2G8Canada

Wetting of a liquid droplet on another liquid substrate is governed by the well-known Neumann *** present work aims to develop an explicit modified version of the Neumann equations for axisymmetric wetting of a liquid droplet on a highly stretched elastic membrane of non-zero bending *** explicit modified form of the Neumann equations is derived to determine the two contact angles,which is reduced to Young's equation for a liquid droplet on a rigid membrane or to the Neumann equations for a liquid droplet on another liquid *** implications of the modified Neumann equations are examined by comparison with some previous results reported in the recent literature,particularly considering the ranges of material and geometrical parameters of the liquid droplet-membrane system which have not been recently addressed in the literature.

关键词： Neumann equation Young's equation liquid droplet membrane pretension

Mechanical properties of cocoons constructed consecutively by a single silkworm caterpillar,Bombyx mori

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Acta Mechanica sinica 2008年第2期24卷 151-160页

作者： s.q.Huang H.P.Zhao X.q.Feng W.Cui Z.Lin M.q.Xu Department of Engineering Mechanics FML Tsinghua University Beijing 100084 China Department of sericulture Shandong Agriculture University Tai'an 271018 China Department of Landscape Architecture Human Environment-Biological Polytechnic College. Hengyang 421005 China

Most animals have the ability to adapt, to some extends and in different ways, the variation or disturbance of environment. In our experiments, we forced a silkworm caterpillar to spin two, three or four thin cocoons by taking it out from the cocoon being constructed. The mechanical properties of these cocoons were studied by static tensile tests and dynamic mechanical thermal analysis. Though external disturbances may cause the decrease in the total weight of silk spun by the silkworm, a gradual enhancement was interestingly found in the mechanical properties of these thin cocoons. scanning electron microscopy observations of the fractured specimens of the cocoons showed that there exist several different energy dissipation mechanisms occurred simultaneously at macro-, meso-, and micro-scales, yielding a superior capacity of cocoons to adsorb the energy of possible attacks from the outside and to protect efficiently its pupa against damage. Through evolution of millions of years, therefore, the silkworm Bombyx mori seems to have gained the ability to adapt external disturbances and to redesign a new cocoon with optimized protective function when its first cocoon has been damaged for some reasons.

关键词： silk silkworm cocoon Mechanical property Biomimetics

Interfacial Instability of Two Bonded Elastic Bodies Driven by Interface or Bulk Residual stress

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Acta Mechanica solida sinica 2023年第6期36卷 914-920页

作者： C.q.Ru Department of Mechanical Engineering University of AlbertaEdmonton T6G 2G8Canada

Inspired by recent research interest in the interface wrinkling of bonded materials in diverse areas of 3D printing,the present work studies the interfacial instability of two bonded elastic bodies driven by negative interfacial tension or compressible bulk residual *** interfacial instability modes decaying exponentially with distance from the interface,the present model is formulated for two bonded elastic half-spaces with a planar interface under plane *** explicit expression is given for the wavenumber of interfacial instability driven by negative interfacial tension,and a critical condition is derived for interfacial instability driven by compressive bulk residual *** derived results are validated with comparison to known results on surface instability of an elastic half-space,and the role of shear modulus ratio and Poisson’s ratios of two bonded elastic bodies in interfacial instability,an issue to be addressed in literature,is studied with specific reference to material parameters used in some areas of 3D printing.

关键词： Interfacial tension surface tension Interfacial instability 3D printing Interface wrinkling

First-principles Investigation of Bi segregation at the solder Interface of Cu/Cu_3sn(010)

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Journal of Materials science & Technology 2010年第12期26卷 1057-1062页

作者： X.Y. Pang Z.q. Liu s.q. Wang J.K. shang shenyang National Laboratory for Materials science Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China Department of Materials science and Engineering University of Illinois at Urbana-Champaign IL 61801 USA

Density functional theory was employed to investigate the bismuth segregation at Cu/Cu3sn（010） interface. Five initial constructions were introduced by adopting the adhesion energy criterion. Among them, the so-called ＂between-Cu＂ construction in which the interface Cu atoms of Cu slab locate along Cu-Cu bond direction in Cu3sn slab was found to be the most energy-favored at an adhesion energy of 1.96 J/m^2. Based on this construction, five possible segregation sites were examined, and the most likely segregation site was determined with adhesion energy as low as 1.06 J/m^2, which was almost half of the initial one. Comparing with other sitest adhesion energies, it was concluded that size effect took a large part in embrittlement. The analyses of atomic structure and electronic density revealed that the slabs shifted away from interfaces due to bismuth segregation, and the atoms around Bi atom were Dressed away. This calculated work agreed aualitativelv with reported experimental results.

关键词： First-principles calculation segregation Bismuth Interface snBi solder

Electrostatic Nonlinear structures in Dissipative Electron-Positron-Ion quantum Plasmas

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Chinese Physics Letters 2008年第12期25卷 4329-4332页

作者： s. A. Khan q. Haque Department of Physics COMSATS Institute of Information Technology Islamabad Pakistan and Department of Physics Government College Bagh 12500 AJK Pakistan Theoretical Plasma Physics Division PINSTECH P. O. Nilore Islamabad Pakistan

Low frequency （in comparison to ion plasma frequency） ion-acoustic shocks and solitons in superdense electronpositron-ion quantum plasmas are studied. The quantum hydrodynamic model is used incorporating quantum Bohm forces and Fermi-Dirac statistical corrections to derive the deformed Korteweg de Vries-Burgers （dKdVB） equation in weakly nonlinear limit. The travelling wave solution of dKdVB equation is presented and results are discussed in different limits. It is found that shock height increases with increase of quantum pressure, positron concentration and dissipation. Further, it is seen that the width of soliton decreases with increase of quantum pressure

关键词： Nonlinear structure Ion quantum Plasmas

Damped electrostatic ion acoustic solitary wave structures in quantum plasmas with Bohm potential and spin effects

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Chinese Physics B 2019年第1期28卷 460-465页

作者： s Hussain H Hasnain Mahnaz q.Haseeb Theoretical Physics Division(TPD) Department of Physics COMSATS University

Nonlinear properties of ion acoustic solitary waves are studied in the case of dense magnetized plasmas. The degenerate electrons with relative density effects from their spin states in the same direction and from equally probable up and down spinning states are taken up separately. quantum statistical as well as quantum tunneling effects for both types of electrons are taken. The ions have large inertia and are considered classically, whereas the electrons are degenerate. The collisions of ions and electrons with neutral atoms are considered. We derive the deformed Korteweg de–Vries(DKdV)equation for small amplitude electrostatic potential disturbances by employing the reductive perturbation technique. The Runge–Kutta method is applied to solve numerically the DKdV equation. The analytical solution of DKdV is also presented with time dependence. We discuss the profiles for velocity, amplitude, and time variations in solitons for the cases when all the electrons are spinning in the same direction and for the case when there is equal probability of electrons having spin up and spin down. We have found that the wave is unstable because of the collisions between neutral gas molecules and the charged plasmas particles in the presence of degenerate electrons.

关键词： degenerate plasma collisions spin-up spin-down