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Effect of sodium modification on microstructure and mechanical properties of thick-walled AlSi6Cu2.5 rheocast component

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Transactions of nonferrous metals Society of China 2010年第9期20卷 1643-1648页

作者： m.wessn n.E.AnDE RSSOn O.GRAnATH School of Engineering Materials and Manufacturing-CastingJnkping University

The microstructure and tensile properties were investigated in a thick-walled section （approximately 45 mm×43 mm） of a rheocast component produced by the RheometalTm process. Due to the long solidification period of such components, it is expected that the A1-Si eutectic formed will be coarse. Therefore, sodium （na） was used as a modifying agent to reduce the coarseness of the eutectic. Tensile test bars were machined from three different sets of materials： 1） non-modified melt, 2） modified melt cast directly after na addition, and 3） modified melt cast 30 min after na addition. The alloy used was a secondary AlSi6Cu2.5 alloy （STEnAL Rheol）, specially developed for rheocasting. The material was studied in the as-cast condition as well as after a T6 heat treatment. The results show that the Al-Si eutectic is significantly refined by the na addition, even after a fading time of 30 min. However, it is observed that the na modification generally has a detrimental effect on the mechanical properties, despite the structure refinement. This is especially true in the T6 heat treated condition, where the yield strength is reduced by more than 30%. Some possible mechanisms for the degradation of mechanical performance are discussed.

关键词： rheocasting thick-walled component eutectic modification mechanical properties sodium Al alloys

neurocircuit regeneration by extracellular matrix reprogramming

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neural Regeneration Research 2025年第8期20卷 2300-2301页

作者： Shengzhang Su Ian n.Levasseur Kimberly m.Alonge Department of medicinal Chemistry University of WashingtonSeattleWAUSA Department of Chemistry University of WashingtonSeattleWAUSA Department of medicine University of Washington Medicine Diabetes InstituteSeattleWAUSA

The brain's extracellular matrix(ECm),which is comprised of protein and glycosaminoglycan(GAG)scaffolds,constitutes 20%-40% of the human brain and is considered one of the largest influencers on brain cell functioning(Soles et al.,2023).Synthesized by neural and glial cells,the brain's ECm regulates a myriad of homeostatic cellular processes,including neuronal plasticity and firing(miyata et al.,2012),cation buffering(moraws ki et al.,2015),and glia-neuron interactions(Anderson et al.,2016).Considering the diversity of functions,dynamic remodeling of the brain's ECm indicates that this understudied medium is an active participant in both normal physiology and neurological diseases.

关键词： matrix programming

Regulator of G protein signaling 6 mediates exercise-induced recovery of hippocampal neurogenesis,learning,and memory in a mouse model of Alzheimer’s disease

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neural Regeneration Research 2025年第10期20卷 2969-2981页

作者： mackenzie m.Spicer Jianqi Yang Daniel Fu Alison n.DeVore marisol Lauffer nilufer S.Atasoy Deniz Atasoy Rory A.Fisher Department of neuroscience and Pharmacology University of Iowa Carver College of MedicineIowa CityIAUSA Iowa neuroscience Institute University of Iowa Carver College of MedicineIowa CityIAUSA Interdisciplinary Graduate Program in molecular medicine University of Iowa Carver College of MedicineIowa CityIAUSA neural Circuits and Behavior Core University of Iowa Carver College of MedicineIowa CityIAUSA

Hippocampal neuronal loss causes cognitive dysfunction in Alzheimer’s *** hippocampal neurogenesis is reduced in patients with Alzheimer’s *** stimulates adult hippocampal neurogenesis in rodents and improves memory and slows cognitive decline in patients with Alzheimer’s ***,the molecular pathways for exercise-induced adult hippocampal neurogenesis and improved cognition in Alzheimer’s disease are poorly ***,regulator of G protein signaling 6(RGS6)was identified as the mediator of voluntary running-induced adult hippocampal neurogenesis in ***,we generated novel RGS6fl/fl;APP_(SWE) mice and used retroviral approaches to examine the impact of RGS6 deletion from dentate gyrus neuronal progenitor cells on voluntary running-induced adult hippocampal neurogenesis and cognition in an amyloid-based Alzheimer’s disease mouse *** found that voluntary running in APP_(SWE) mice restored their hippocampal cognitive impairments to that of control *** cognitive rescue was abolished by RGS6 deletion in dentate gyrus neuronal progenitor cells,which also abolished running-mediated increases in adult hippocampal *** hippocampal neurogenesis was reduced in sedentary APP_(SWE) mice versus control mice,with basal adult hippocampal neurogenesis reduced by RGS6 deletion in dentate gyrus neural precursor ***6 was expressed in neurons within the dentate gyrus of patients with Alzheimer’s disease with significant loss of these RGS6-expressing ***,RGS6 mediated voluntary running-induced rescue of impaired cognition and adult hippocampal neurogenesis in APP_(SWE) mice,identifying RGS6 in dentate gyrus neural precursor cells as a possible therapeutic target in Alzheimer’s disease.

关键词： adult hippocampal neurogenesis Alzheimer’s disease dentate gyrus exercise learning/memory neural precursor cells regulator of G protein signaling 6(RGS6)

Amyloid-beta pathology-induced nanoscale synaptic disruption:the case of the GABA_B-GIRK assembly

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neural Regeneration Research 2025年第5期20卷 1409-1410页

作者： Rafael Lujan Alejandro martín-Belmonte Sergi Ferré Francisco Ciruela Synaptic Structure Laboratory Instituto de Biomedicina de la UCLM(IB-UCLM)Departamento de Ciencias MédicasInstituto de Investigación en Salud de Castilla-La Mancha(IDISCAM)Facultad de MedicinaUniversidad Castilla-La ManchaCampus BiosanitarioC/AlmansaAlbaceteSpain Integrative neurobiology Section National Institute on Drug AbuseIntramural Research ProgramNational Institutes of HealthBaltimoreMDUSA Pharmacology Unit Department of Pathology and Experimental TherapeuticsSchool of Medicine and Health SciencesInstitute of NeurosciencesUniversity of BarcelonaNeuropharmacology&Pain GroupNeuroscience ProgramBellvitge Institute for Biomedical ResearchL’Hospitalet de LlobregatSpain

Alzheimer's disease (AD) is characterized by an imbalance between excitatory and inhibitory brain networks,leading to aberrant homeostatic synaptic *** has progressively been recognized as syna ptopathy and syna ptic dysfunction has been identified as a key component of its pathogenesis (Schirinzi et al.,2020).Syna ptic dysfunction is believed to precede synapse loss,a primary biological correlate of cognitive decline in AD,inevita bly associated with neuronal death.

关键词： Alzheimer pathology

The sexually dimorphic expression of glutamate transporters and their implication in pain after spinal cord injury

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neural Regeneration Research 2025年第11期20卷 3317-3329页

作者： Jennifer m.Colón-mercado Aranza I.Torrado-Tapias Iris K.Salgado Jose m.Santiago Samuel E.Ocasio Rivera Dina P.Bracho-Rincon Luis H.Pagan Rivera Jorge D.miranda Department of Physiology University of Puerto RicoMedical Sciences CampusSan JuanPRUSA national Institutes of Health National Human Genome Research InstituteBethesdaMDUSA Universidad Central del Caribe School of MedicineBayamónPRUSA University of Puerto Rico Carolina CampusCarolinaPRUSA Institute of neurobiology San JuanPRUSA

In addition to the loss of motor function,~60% of patients develop pain after spinal cord *** cellular-molecular mechanisms are not well understood,but the data suggests that plasticity within the rostral,epicenter,and caudal penumbra of the injury site initiates a cellularmolecular interplay that acts as a rewiring mechanism leading to central neuropathic *** can lead to the formation of new connections triggering abnormal sensory *** excitatory glutamate transporters are responsible for the reuptake of extracellular glutamate which makes them a critical target to prevent neuronal hyperexcitability and *** previous studies showed a sexually dimorphic therapeutic window for spinal cord injury after treatment with the selective estrogen receptor modulator *** this study,we investigated the anti-allodynic effects of tamoxifen in male and female rats with spinal cord *** hypothesized that tamoxifen exerts anti-allodynic effects by increasing the expression of glutamate transporters,leading to reduced hyperexcitability of the secondary neuron or by decreasing aberrant *** and female rats received a moderate contusion to the thoracic spinal cord followed by subcutaneous slow-release treatment of tamoxifen or matrix pellets as a control(placebo).We used von Frey monofilaments and the“up-down method”to evaluate mechanical *** treatment decreased allodynia only in female rats with spinal cord injury revealing a sexdependent *** expression profile of glutamatergic transporters(excitatory amino acid transporter 1/glutamate aspartate transporter and excitatory amino acid transporter 2/glutamate transporter-1)revealed a sexual dimorphism in the rostral,epicenter,and caudal areas of the spinal cord with a pattern of expression primarily on *** rodents showed a significantly higher level of excitatory amino acid transporter-1 expression while male rodents showed increased

关键词： allodynia central neuropathic pain EAAT-1/GLAST EAAT-2/GLT-1 glutamate transporters selective estrogen receptor modulator sexual dimorphism spinal cord injury trauma

Brain-derived neurotrophic factor signaling in the neuromuscular junction during developmental axonal competition and synapse elimination

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neural Regeneration Research 2025年第2期20卷 394-401页

作者： Josep Tomàs Víctor Cilleros-mañé Laia Just-Borràs marta Balanyà-Segura Aleksandra Polishchuk Laura nadal marta Tomàs Carolina Silvera-Simón manel m.Santafé maria A.Lanuza Unitat d’Histologia i neurobiologia(UHneurob) Facultat de Medicina i Ciències de la SalutUniversitat Rovira i VirgiliReusSpain

During the development of the nervous system,there is an overproduction of neurons and *** competition between neighboring nerve endings and synapses performing different activity levels leads to their elimination or *** have extensively studied the involvement of the brain-derived neurotrophic factor-Tropomyosin-related kinase B receptor neurotrophic retrograde pathway,at the neuromuscular junction,in the axonal development and synapse elimination process versus the synapse *** purpose of this review is to describe the neurotrophic influence on developmental synapse elimination,in relation to other molecular pathways that we and others have found to regulate this *** particular,we summarize our published results based on transmitter release analysis and axonal counts to show the different involvement of the presynaptic acetylcholine muscarinic autoreceptors,coupled to downstream serine-threonine protein kinases A and C(PKA and PKC)and voltage-gated calcium channels,at different nerve endings in developmental *** dynamic changes that occur simultaneously in several nerve terminals and synapses converge across a postsynaptic site,influence each other,and require careful studies to individualize the mechanisms of specific *** describe an activity-dependent balance(related to the extent of transmitter release)between the presynaptic muscarinic subtypes and the neurotrophin-mediated TrkB/p75nTR pathways that can influence the timing and fate of the competitive interactions between the different axon *** downstream displacement of the PKA/PKC activity ratio to lower values,both in competing nerve terminals and at postsynaptic sites,plays a relevant role in controlling the elimination of supernumerary ***,calcium entry through L-and P/Q-subtypes of voltage-gated calcium channels(both channels are present,together with the n-type channel in developing nerve terminals)contributes to red

关键词： acetylcholine release adenosine receptors axonal competition brain-derived neurotrophic factor calcium channels motor end-plate muscarinic acetylcholine receptors postnatal synapse elimination serine kinases tropomyosin-related kinase receptorB

nonlinear forced vibration in a subcritical regime of a porous functionally graded pipe conveying fluid with a retaining clip

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Applied mathematics and mechanics(English Edition) 2025年第1期46卷 101-122页

作者： m.GHOLAmI m.EFTEKHARI Department of mechanical Engineering Shahid Bahonar University of Kerman

This study examines the nonlinear behaviors of a clamped-clamped porous pipe made of a functionally graded material(FGm) that conveys fluids and is equipped with a retaining clip, focusing on primary resonance and subcritical dynamics. The nonlinear governing equations for the FGm pipe are derived by the extended Hamilton's principle, and subsequently discretized through the application of the Galerkin *** direct method of multi-scales is then used to solve the derived equations. A thorough analysis of various parameters, including the clip stiffness, the power-law index, the porosity, and the clip location, is conducted to gain a comprehensive understanding of the system's nonlinear dynamics. Through the analysis of the first natural frequency, the study highlights the influence of the flow velocity and the clip stiffness, while the comparisons with metallic pipes emphasize the role of FGm composition. The examination of the forced response curves reveals saddle-node bifurcations and their dependence on parameters such as the detuning parameter and the power-law index, offering valuable insights into the system's nonlinear resonant behavior. Furthermore, the frequency-response curves illustrate the hardening nonlinearities influenced by factors such as the porosity and the clip stiffness, revealing nuanced effects on the system response and resonance characteristics. This comprehensive analysis enhances the understanding of nonlinear behaviors in FGm porous pipes with a retaining clip, providing key insights for practical engineering applications in system design and optimization.

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Influence of FCA Welding Process Parameters on Distortion of 409m Stainless Steel for Rail Coach Building

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Journal of Iron and Steel Research International 2013年第1期20卷 71-78页

作者： m V Venkatesan n murugan B m Prasad A manickavasagam Department of mechanical Engineering Coimbatore Institute of TechnologyCoimbatore 641014TNIndia Integral Coach Factory Indian RailwaysChennai 600038TNIndia

The influence of flux cored arc welding （FCAW） process parameters such as welding current, travel speed, voltage and CO2 shielding gas flow rate on bowing distortion of 409m ferritic stainless steel sheets of 2 mm in thickness was discussed. The bowing distortions of the welded plates were measured using a simple device called profile tracer. An experimental regression equation was developed to predict the bowing distortion and with this equation, it is easy to select optimized process parameters to achieve minimum bowing distortion. It is revealed that the FCAW process parameters have significant influence on bead profile and the bowing distortion.

关键词： bowing distortion ferritic stainless steel flux cored arc welding statistical model rail coach distortion measurement

Antimonene-based saturable absorber for a soliton mode-locked and Q-switched fiber laser in the 2 μm wavelength region

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Chinese Physics B 2023年第6期32卷 259-269页

作者： H Ahmad B nizamani m Z Samion n Yusoff m F Ismail Photonics Research Centre Universiti Malaya50603 Kuala LumpurMalaysia Physics Department Faculty of ScienceUniversiti Malaya50603 Kuala LumpurMalaysia Distinguished Visiting Professor Universiti Kuala Lumpur British Malaysian Institute(UniKL BMI)Batu 8Jln Sungai Pusu53100SelangorMalaysia

We demonstrate antimonene as a saturable absorber(SA) to generate an ultrafast mode-locked and Q-switched laser in the 2 μm wavelength region. The two antimonene-based SAs were prepared and inserted separately in a thulium–holmiumdoped fiber laser to produce the pulsed laser. Antimonene was coated onto a tapered fiber to generate soliton mode-locked pulses and used in thin-film form for the generation of Q-switched pulses. The mode-locking was stable within a pump power of 267 m W–511 m W, and the laser operated at a central wavelength of 1897.4 nm. The mode-locked laser had a pulse width of 1.3 ps and a repetition rate of 12.6 mHz, with a signal-to-noise ratio of 64 d B. Q-switched laser operation was stable at a wavelength of 1890.1 nm within a pump power of 312 m W–381 m W. With the increase in pump power from 312 m W to 381 m W, the repetition rate increased to a maximum of 56.63 k Hz and the pulse width decreased to a minimum value of 2.85 μs. Wide-range tunability of the Q-switched laser was also realized within the wavelength range of1882 nm–1936 nm.

关键词： mode-locking Q-switched fiber laser optical saturable absorber