检索结果-南通市图书馆

Gauging universe expansion via scalar fields

在线全文

学校读者我要写书评

暂无评论

Chinese Physics C 2023年第5期47卷 211-220页

作者： devanarayanan Rajeeb Kumar s.d.pathak Vikash Kumar Ojha department of Physics Lovely Professional UniversityPhagwara 144411PunjabIndia department of Physics SVNIT SuratIchchhanathSurat 395007GujaratIndia

In this study,we investigate the expansion of the FRLW universe in the open,closed,and flat *** universe is dominated by a scalar field(spatially homogeneous)as a source of dark *** consider the three different classes of scalar fields-quintessence,tachyonic,and phantom field-for our analysis.A mathematical analysis is carried out by considering these three scalar fields with exponential and power-law *** potentials give exponential expansion in the open,closed,and flat FRLW *** is found that quintessence,tachyonic,and phantom scalar fields are indistinguishable under the slow roll approximation.

关键词： quientessence tachyonic scalar field phantom field dark energy

同方期刊数据库

A comprehensive investigation on nonlinear vibration and bending characteristics of bio-inspired helicoidal laminated composite structures

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2025年第1期46卷 81-100页

作者： s.sAURABH R.KIRAN d.sINGH R.VAIsH V.s.CHAUHAN school of Mechanical and Materials Engineering Indian Institute of Technology Mandi

Bio-inspired helicoidal composite laminates, inspired by the intricate helical structures found in nature, present a promising frontier for enhancing the mechanical properties of structural designs. Hence, this study provides a comprehensive investigation into the nonlinear free vibration and nonlinear bending behavior of bio-inspired composite plates. The inverse hyperbolic shear deformation theory(IHsdT) of plates is employed to characterize the displacement field, with the incorporation of Green-Lagrange nonlinearity. The problem is modeled using the C0finite element method(FEM), and an in-house code is developed in the MATLAB environment to solve it numerically. Various helicoidal layup configurations including helicoidal recursive(HR), helicoidal exponential(HE), helicoidal semi-circular(Hs), linear helicoidal(LH), and Fibonacci helicoidal(FH)with different layup sequences and quasi-isotropic configurations are studied. The model is validated, and parametric studies are conducted. These studies investigate the effects of layup configurations, side-to-thickness ratio, modulus ratios, boundary conditions, and loading conditions at different load amplitudes on the nonlinear vibration and nonlinear bending behaviors of bio-inspired composite plates. The results show that the laminate sequence exerts a substantial impact on both nonlinear natural frequencies and nonlinear bending behaviors. Moreover, this influence varies across different side-to-thickness ratios and boundary conditions of the bio-inspired composite plate.

关键词：

Effect of austenitization temperature on microstructure and mechanical properties of low-carbon-equivalent carbidic austempered ductile iron

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2018年第7期25卷 770-778页

作者： vinayak dakre d.r.peshwe s.u.pathak ajay likhite department of Metallurgical ＆ Materials Engineering Visvesvaraya National Institute of TechnologyNagpur 440010India

The wear resistances of austempered ductile iron （AdI） were improved through intxoduction of a new phase （carbide） into the ma- txix by addition of chromium. In the present investigation, low-caxbon-equivalent ductile iron （LCEdI）（CE = 3.06%, and CE represents cax- bon-equivalent） with 2.42% chromium was selected. LCEdI was austeintized at two difl＇erent temperatures （900 and 975~C） a^ld soaked for 1 h and then quenched in a salt bath at 325~C for 0 to 10 h. samples were analyzed using optical microscopy and X-ray diffraction. Wear tests were carded out on a pin-on-disk-type machine. The efl＇ect of austenization temperature on the wear resistance, impact strength, and the mi- crostructure was evaluated. A stxucture-property correlation based on the observations is established.

关键词： low carbon equivalent ductile iron (LCEdI) caxbidic austempered ductile iron (CAdI) wear test austenitization temperature impact strength

Machine learning assisted design of shape-programmable 3d kirigami metamaterials

在线全文

学校读者我要写书评

暂无评论

npj Computational Materials 2022年第1期8卷 1817-1828页

作者： Nicolas A.Alderete Nibir pathak Horacio d.Espinosa Theoretical and Applied Mechanics Northwestern UniversityEvanstonIL60208USA department of Mechanical Engineering Northwestern UniversityEvanstonIL60208USA

Kirigami-engineering has become an avenue for realizing multifunctional metamaterials that tap into the instability landscape of planar surfaces embedded with ***,it has been shown that two-dimensional Kirigami motifs can unfurl a rich space of out-of-plane deformations,which are programmable and controllable across spatial *** Kirigami’s versatility,arriving at a cut layout that yields the desired functionality remains a ***,we introduce a comprehensive machine learning framework to shed light on the Kirigami design space and to rationally guide the design and control of Kirigami-based materials from the meta-atom to the metamaterial *** employ a combination of clustering,tandem neural networks,and symbolic regression analyses to obtain Kirigami that fulfills specific design constraints and inform on their control and *** systematic approach is experimentally demonstrated by examining a variety of applications at different hierarchical levels,effectively providing a tool for the discovery of shape-shifting Kirigami metamaterials.

关键词： shape hierarchical shifting

Anti-amyloid antibodies in Alzheimer’s disease: what did clinical trials teach us?

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Neural Regeneration Research 2025年第4期20卷 1092-1093页

作者： danko Jeremic Lydia Jiménez-díaz Juan d.Navarro-López NeuroPhysiology&Behavior Lab University of Castilla-La ManchaBiomedical Research Center(CRIB)School of Medicine of Ciudad RealCiudad RealSpain

Although many causes of Alzheimer’s disease(Ad)may exist,both the original amyloid cascade and tau hypotheses posit that abnormal misfolding and accumulation of amyloid-β(Aβ)and tau protein is the central event causing the ***,that conclusion could be only partly true,and there is conflicting evidence about the role of both proteins in Ad,being able to precede and influence one *** researchers argue that these proteins are mere executors rather than primary causes of ***,there have been continuing refinements of both hypotheses,with alternative explanations proposed.Aβand tau proteins may be independently involved in specific neurotoxic pathways;yet there may be other crucial processes going on in early ***,accumulating evidence suggests that Aβand tau act synergistically,rather than additively in disease onset(Jeremic et al.,2021,2023a).

关键词： amyloid Alzheimer additive

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

在线全文

学校读者我要写书评

暂无评论

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

Revisiting cerebral endothelial cells in Alzheimer’s disease

在线全文

学校读者我要写书评

暂无评论

Neural Regeneration Research 2025年第10期20卷 2911-2912页

作者： Amira s.Hanafy department of Neurosurgery University Hospital BonnBonnGermany

Alzheimer’s disease(Ad)is the most common neurodegenerative disorder characterized by slow and progressive decline of cognitive and memory *** only approximately 5%of the cases,Ad is familial,as often predisposed by genetic mutations(Hoogmartens et al.,2021),while sporadic Ad accounts for approximately 95%of the *** amyloid cascade hypothesis is one of the fundamental hypotheses put out to explain Ad pathogenesis as dysregulated homeostasis of amyloid-β(Aβ)peptides that leads to the accumulation of Aβplaques in the parenchyma,an anatomical hallmark of Ad.

关键词： Alzheimer Aβ cerebral

A systematic review of progenitor survival and maturation in Parkinsonian models

在线全文

学校读者我要写书评

暂无评论

Neural Regeneration Research 2025年第11期20卷 3172-3178页

作者： Giulia Comini Eilís dowd Pharmacology&Therapeutics and Galway Neuroscience Center University of GalwayGalwayIreland

stem cell-based brain repair is a promising emergent therapy for Parkinson's disease based on years of foundational research using human fetal donors as a cell *** current therapeutic options for patients,this approach has the potential to provide longterm stem cell–derived reconstruction and restoration of the dopaminergic input to denervated regions of the brain allowing for restoration of certain functions to *** ultimate clinical success of stem cell–derived brain repair will depend on both the safety and efficacy of the approach and the latter is dependent on the ability of the transplanted cells to survive and differentiate into functional dopaminergic neurons in the Parkinsonian *** the pre-clinical literature suggests that there is considerable variability in survival and differentiation between studies,the aim of this systematic review was to assess these parameters in human stem cell-derived dopaminergic progenitor transplant studies in animal models of Parkinson's disease.A defined systematic search of the PubMed database was completed to identify relevant studies published up to March *** screening,76 articles were included in the analysis from which 178 separate transplant studies were *** these,graft survival could be assessed in 52 studies and differentiation in 129 ***,we found that graft survival ranged froms transplanted,with a median of 51%of transplanted cells surviving in the brain;while dopaminergic differentiation of the cells ranged from 0% to 46% of cells transplanted with a median of 3%.This systematic review suggests that there is considerable scope for improvement in the differentiation of stem cell-derived dopaminergic progenitors to maximize the therapeutic potential of this approach for patients.

关键词： cell replacement therapy differentiation embryonic stem cells graft induced pluripotent stem cells Parkinson's disease survival transplant

deciphering the mechanobiology of microglia in traumatic brain injury with advanced microsystems

在线全文

学校读者我要写书评

暂无评论

Neural Regeneration Research 2025年第8期20卷 2304-2306页

作者： Anthony Procès sylvain Gabriele Univ.Grenoble Alpes InsermU1216Grenoble Institut des NeurosciencesGrenobleFrance Mechanobiology&Biomaterials Group CIRMAPResearch Institute for BiosciencesUniversity of MonsMonsBelgium

Advanced microsystems in traumatic brain injury research:Traumatic brain injury(TBI)results from a mechanical insult to the brain,leading to neuronal and axonal damage and subsequently causing a secondary *** minutes ... 详细信息

关键词： traumatic injury damage