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Dynamic stress concentration in an infinitely long cylindrical cavity due to a point spherical source embedded within a fluid-saturated poroelastic formation of infinite extent

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Applied Mathematics and Mechanics(english edition) 2025年第1期46卷 139-156页

作者： H.HoSSeINI o.BALILASHAKI Department of Mechanical engineering Faculty of EngineeringGolestan University

The effects of a harmonically exciting monopole source on an infinitely long cylindrical cavity embedded entirely within a fluid-saturated poroelastic formation of infinite extent are examined theoretically. It is assumed that the source is located outside the cavity at a specified distance from the borehole axis. The magnitudes of the hoop and radial stresses beside the pore pressures exerted on the interface and inside the porous medium surrounding the borehole are calculated and discussed. Biot's poroelastic modeling along with three types of boundary conditions for the cylindrical interface including the ideal fluid, empty borehole, and rigid inclusion with a hard boundary is employed for the analysis. Utilizing a proper translational addition theorem for expressing the incident spherical wave in terms of cylindrical wave expansions, the proposed boundary conditions at the interface are satisfied. Stresses are formulated by means of wave potential functions in a three-dimensional(3D) manner. The effects of the frequency and the radial distance between the source and borehole on the induced stresses are examined for the first cylindrical modes over frequency spectra. Two permeability conditions for the interface and three types of soils for the porous formation are considered throughout the analysis. To give an overall outline of the study, a numerical example is presented. The results clearly indicate that the distance is a key parameter and has considerable effects on the induced stress values. In addition, the interface permeability condition and soil characteristics play an important role in determining the dynamic response of the borehole. Finally,the obtained results are compared with the relevant analyses existing in the literature for some limit cases, and good agreement is achieved.

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Neuroinflammation revisited through the microglial lens

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Neural Regeneration Research 2025年第7期20卷 1989-1990页

作者： Renato Socodato João B.Relvas Institute of Research and Innovation in Health(i3S)and Institute for Molecular and Cell Biology(IBMC) University of PortoPortoPortugal Department of Biomedicine Faculty of Medicine of the University of Porto(FMUP)PortoPortugal

Neuroimmunology is emerging as a pivotal field,shedding light on the intricate dialogues between the central nervous system(CNS)and the immune *** exploration is particularly significant in understanding microglia,the CNS’s innate immune cells,beyond the conventional conflation of“neuroinflammation”and“microglial activation.”This conflation has clouded the true complexity of these processes,potentially stalling scientific progress and the development of new *** challenge the long-standing perspectives that have oversimplified these interactions,advocating for a deeper exploration of the dynamic relationship between neuroinflammation and microglial *** dissecting specific molecular pathways,we aim to illuminate their elaborate roles in neuroinflammatory responses,especially in the context of Alzheimer’s disease(AD).Here,neuroinflammation is not merely a passive observer or a direct antagonist but a complex agent in the disease’s *** article calls for a significant paradigm shift towards an integrative,multi-omics approach to *** such a comprehensive framework is crucial for advancing our understanding of neuroinflammatory conditions and paving the way for targeted therapeutic strategies for brain diseases.

关键词： inflammation simplified activation

Contribution of mechanical forces to structural synaptic plasticity:insights from 3D cellular motility mechanisms

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Neural Regeneration Research 2025年第7期20卷 1995-1996页

作者： Rita o.Teodoro Mafalda Ribeiro Ramos Lara Carvalho iNoVA4Health NOVA Medical School|Faculdade de Ciências MédicasNMS|FCMUniversidade Nova de LisboaLisboaPortugal

Cells,tissues,and organs are constantly subjected to the action of mechanical forces from the extracellular environment-and the nervous system is no ***-intrinsic properties such as membrane lipid composition,abundance of mechanosensors,and cytoskeletal dynamics make cells more or less likely to sense these *** and extrinsic cues are integrated by cells and this combined information determines the rate and dynamics of membrane protrusion growth or retraction(Yamada and Sixt,2019).Cell protrusions are extensions of the plasma membrane that play crucial roles in diverse contexts such as cell migration and neuronal synapse *** the nervous system,neurons are highly dynamic cells that can change the size and number of their pre-and postsynaptic elements(called synaptic boutons and dendritic spines,respectively),in response to changes in the levels of synaptic activity through a process called *** plasticity is a hallmark of the nervous system and is present throughout our lives,being required for functions like memory formation or the learning of new motor skills(Minegishi et al.,2023;Pillai and Franze,2024).

关键词： plasticity structural mechanisms

Apples to oranges:environmentally derived,dynamic regulation of serotonin neuron subpopulations in adulthood?

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Neural Regeneration Research 2025年第9期20卷 2596-2597页

作者： Christopher J.o’Connell Matthew J.Robson Department of Genetics College of MedicineHarvard UniversityBostonMAUSA James L.Winkle College of Pharmacy Division of Pharmaceutical SciencesUniversity of CincinnatiCincinnatiOHUSA Neuroscience Graduate Program College of MedicineUniversity of CincinnatiCincinnatiOHUSA

Traumatic brain injury(TBI)is a public health problem with an undue economic burden that impacts nearly every age,ethnic,and gender group across the globe(Capizzi et al.,2020).TBIs are often sustained during a dynamic range of exposures to energetic environmental forces and as such outcomes are typically heterogeneous regarding severity and pathology(Capizzi et al.,2020).

关键词： sustained orange dynamic

Polyethylene glycol has immunoprotective effects on sciatic allografts, but behavioral recovery and graft tolerance require neurorrhaphy and axonal fusion

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Neural Regeneration Research 2025年第4期20卷 1192-1206页

作者： Tyler A.Smith Liwen Zhou Cameron L.Ghergherehchi Michelle Mikesh Cathy Z.Yang Haley o.Tucker JuliAnne Allgood Jared S.Bushman George D.Bittner Department of Molecular Biosciences University of Texas at AustinAustinTXUSA Department of Neuroscience University of Texas at AustinAustinTXUSA Division of Pharmaceutical Sciences University of WyomingLaramieWYUSA

Behavioral recovery using(viable)peripheral nerve allografts to repair ablation-type(segmental-loss)peripheral nerve injuries is delayed or poor due to slow and inaccurate axonal ***,such peripheral nerve allografts undergo immunological rejection by the host immune *** contrast,peripheral nerve injuries repaired by polyethylene glycol fusion of peripheral nerve allografts exhibit excellent behavioral recovery within weeks,reduced immune responses,and many axons do not undergo Wallerian *** relative contribution of neurorrhaphy and polyethylene glycol-fusion of axons versus the effects of polyethylene glycol per se was unknown prior to this *** hypothesized that polyethylene glycol might have some immune-protective effects,but polyethylene glycol-fusion was necessary to prevent Wallerian degeneration and functional/behavioral *** examined how polyethylene glycol solutions per se affect functional and behavioral recovery and peripheral nerve allograft morphological and immunological responses in the absence of polyethylene glycol-induced axonal ***-type sciatic nerve injuries in outbred Sprague–Dawley rats were repaired according to a modified protocol using the same solutions as polyethylene glycol-fused peripheral nerve allografts,but peripheral nerve allografts were loose-sutured(loose-sutured polyethylene glycol)with an intentional gap of 1–2 mm to prevent fusion by polyethylene glycol of peripheral nerve allograft axons with host *** to negative control peripheral nerve allografts not treated by polyethylene glycol and in contrast to polyethylene glycol-fused peripheral nerve allografts,animals with loose-sutured polyethylene glycol peripheral nerve allografts exhibited Wallerian degeneration for all axons and myelin degeneration by 7 days postoperatively and did not recover sciatic-mediated behavioral functions by 42 days *** morphological signs of rejection,such as col

关键词： allograft rejection axotomy macrophage myelin nerve repair polyethylene glycol(PeG) sciatic nerve T cell transplantation Wallerian degeneration

ANALYSIS MoDeL To SIMULATe THe CRACKeD PIPe BURIeD IN SoIL

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Acta Mechanica Sinica 1998年第2期14卷 147-156页

作者：庄茁 P.e.o’Donoghue Department of engineering Mechanics Tsinghua University Beijing China 100084 Department of Civil engineering University College Dublin Earlsfort Terrace Dublin 2 Ireland

The finite element method was used to simulate the crack propagation in a pipeline in the presence of soil backfill. Since typical values for soil modulus are known, a spring element can be used to simulate the effects of backfilled soil on crack propagation. This consists of the relationship between the soil property and the stiffness of the spring element, and the effect of backfill depth on the crack propagation in the pipes. By equating crack driving force, G, in the presence of soil, to the dynamic fracture toughness of the pipeline material, a theoretical predictive capability was obtained for the gas transmission and distribution pipelines. Numerical calculations had also been carried out for the cracked pipe with backfill and without backfill. (edited author abstract) 9 Refs.

关键词： fracture mechanics finite element simulation pipeline soil

Computer simulation of the cluster destruction of stratospheric ozone by bromine

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Chinese Physics B 2012年第11期21卷 198-207页

作者： A.e.Galashev o.R.Rakhmanova Institute of Industrial ecology Ural BranchRussian Academy of Sciences 620990

The interaction of （Br-）i（H2o）50-i, 0 ≤ i ≤ 6 clusters with oxygen and ozone molecules is investigated by the method of molecular dynamics simulation. The ozone molecules as well as the bromine ions do not leave the cluster during the calculation of 25 ps. The ability of the cluster containing molecular oxygen to absorb the infrared （IR） radiation is reduced in the frequency range of 0≤ w ≤ 3500 cm-1 when the number of the bromine ions in the cluster grows. The intensity of the Raman spectrum is not changed significantly when the Brions are added to the ozone- containing system. The power of the emitted IR radiation is increased when the number of bromine ions grows in the oxygen-containing system. The data obtained in this study on the IR and the Raman spectra of the water clusters that contain ozone, oxygen, and Br- can be used to develop an investigation of the mechanisms of ozone depletion.

关键词： bromine ion water cluster ozone infrared and Raman spectra

Thermodynamic second law analysis of magneto-micropolar fluid flow past nonlinear porous media with non-uniform heat source

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Propulsion and Power Research 2020年第3期9卷 281-288页

作者： e.o.Fatunmbi S.o.Salawu Department of Mathematics and Statistics Federal PolytechnicIlaroNigeria Department of Mathematics Landmark UniversityOmu-AranNigeria

This study analyzes the second law of thermodynamic for entropy generation in an irreversible hydromagneto-micropolar flow system with non-homogenous heat *** non-symmetric microstructure fluid flow past a stretching sheet with saturated porous nonlinear media under magnetic field *** the fluid particle deformation,the microstructure is assumed rigid with the viscous suspended *** reduced dimensionless nonlinear formulated model is computationally coded and solved to obtain solutions for the entropy volumetric production,Bejan number and heat transfer magneto-micropolar *** parameter dependent solutions for the flow characteristics and irreversibility processes are plotted and *** is revealed from the study that minimization of entropy generation in a magneto-micropolar flow system is possible by improving the thermodynamic equilibrium with low material variables,viscosity and hysteresis ***,it is seen that the terms that encourage internal heat generation reduces the micropolar fluid viscosity in the system.

关键词： Micropolar Non-Newtonian fluid entropy generation Stretching sheet Thermodynamic law

Approximate analytical solutions and mean energies of stationary Schrodinger equation for general molecular potential

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Chinese Physics B 2021年第7期30卷 116-131页

作者： eyube e S Rawen B o Ibrahim N Department of Physics School of Physical SciencesModibbo Adama University of TechnologyP M B 2076 YolaAdamawa StateNigeria Directorate of Basic and Remedial Studies Abubakar Tafawa Balewa University(ATBU)P M B 750001BauchiBauchi StateNigeria Department of Physics Faculty of ScienceP M B 1069MaiduguriBorno StateNigeria

The Schrodinger equation is solved with general molecular potential via the improved quantization *** for bound state energy eigenvalues,radial eigenfunctions,mean kinetic energy,and potential energy are obtained in compact *** modeling the centrifugal term of the effective potential,a Pekeris-like approximation scheme is ***,we use the Hellmann–Feynman theorem to derive the relation for expectation *** state energy eigenvalues,wave functions and meanenergies of Woods–Saxon potential,Morse potential,Mobius squared and Tietz–Hua oscillators are deduced from the general molecular *** addition,we use our equations to compute the bound state energy eigenvalues and expectation values for four diatomic molecules viz.H_(2),Co,HF,and o_(2).Results obtained are in perfect agreement with the data available from the literature for the potentials and *** also show that as the vibrational quantum number increases,the mean kinetic energy for the system in a Tietz–Hua potential increases slowly to a threshold value and then *** in a Morse potential,the mean kinetic energy increases linearly with vibrational quantum number increasing.

关键词： general molecular potential Schrodinger equation improved quantization rule