检索结果-南通市图书馆

Targeting TrkB–pSD-95 coupling to mitigate neurological disorders

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3期20卷 715-724页

作者： Xin Yang Yu-Wen Alvin Huang john Marshall Department of Molecular Biology Cell Biology and BiochemistryBrown UniversityProvidenceRIUSA Department of Neurology Warren Alpert Medical School of Brown UniversityProvidenceRIUSA Center for Translational Neuroscience Robert J.and Nancy D.Carney Institute for Brain Science and Brown Institute for Translational ScienceBrown UniversityProvidenceRIUSA

Tropomyosin receptor kinase B(TrkB)signaling plays a pivotal role in dendritic growth and dendritic spine formation to promote learning and *** activity-dependent release of brain-derived neurotrophic factor at synapses binds to pre-or postsynaptic TrkB resulting in the strengthening of synapses,reflected by long-term ***,the association of postsynaptic density protein-95 with TrkB enhances phospholipase Cγ-Ca^(2+)/calmodulin-dependent protein kinaseⅡand phosphatidylinositol 3-kinase-mechanistic target of rapamycin signaling required for long-term *** this review,we discuss TrkB-postsynaptic density protein-95 coupling as a promising strategy to magnify brain-derived neurotrophic factor signaling towards the development of novel therapeutics for specific neurological disorders.A reduction of TrkB signaling has been observed in neurodegenerative disorders,such as Alzheimer's disease and Huntington's disease,and enhancement of postsynaptic density protein-95 association with TrkB signaling could mitigate the observed deficiency of neuronal connectivity in schizophrenia and *** with brain-derived neurotrophic factor is problematic,due to poor pharmacokinetics,low brain penetration,and side effects resulting from activation of the p75 neurotrophin receptor or the truncated TrkB.T1 *** TrkB agonists and antibodies that activate TrkB are being intensively investigated,they cannot distinguish the multiple human TrkB splicing isoforms or cell type-specific *** TrkB–postsynaptic density protein-95 coupling provides an alternative approach to specifically boost TrkB signaling at localized synaptic sites versus global stimulation that risks many adverse side effects.

关键词： Angelman syndrome autism brain-derived neurotrophic factor depression neurodegenerative disorder neurodevelopmental disorder postsynaptic density protein-95 synaptic plasticity TrkB

The effect of temperature on load partitioning evolution in magnesium metal matrix composite reinforced with Ti particles using in-situ synchrotron radiation diffraction experiments

在线全文

学校读者我要写书评

暂无评论

Journal of Magnesium and Alloys 2023年第2期11卷 706-719页

作者： G.Garces J.Medina p.perez A.Stark N.schell p.Adeva Department of physical Metallurgy CSICAvenida Gregorio del Amo 8Madrid E-28040Spain Institute of Materials physics Helmholtz-Zentrum HereonMax-Planck-Str.1Geesthacht 21502Germany

The load partitioning between the magnesium and titanium phases in an extruded Mg-15%Ti(vol.%) composite from room temperature up to 300 ℃ using synchrotron radiation diffraction during in-situ compression tests. During compression, the magnesium matrix composite deforms mainly by the activation of the extension twinning system up to 200 ℃. The volume fraction of twins increases with the plastic strain but decrease with the compression temperature. Hard titanium particles bear an additional load transferred by the soft magnesium matrix from room temperature up to 300 ℃. This effect is amplified after yield stress during plastic deformation. Additionally, twins within magnesium grains behaves as an additional reinforcement at low temperature(below 200 ℃) inducing an increase in the work hardening of the composite.

关键词： Magnesium alloys In-situ synchrotron radiationdiffraction plasticity precipitation Dislocationslip Twinning

High temperature mechanical behaviour of Mg-6Zn-1Y alloy with 1 wt.% calcium addition:Reinforcing effect due to I-(Mg3Zn6Yi)and Mg6Zn3Ca2 phases

在线全文

学校读者我要写书评

暂无评论

Journal of Magnesium and Alloys 2020年第4期8卷 1047-1060页

作者： J.Medina G.Garces p.perez A.Stark N.schell p.Adeva Department of physical Metallurgy National Center for Metallurgical Research(CENIM-CSIC)Avenida Gregorio del Amo 828040 MadridSpain Institute of Materials Research Helmholtz-Zentrum GeesthachtMax-Planck-Str.121502 GeesthachtGermany Structural Research on New Materials Helmholtz-Zentrum Geesthacht Outstation at DESYNotkestrafie 8522607 HamburgGermany

The infiuence of small calcium additions on the high-temperature mechanical behaviour in an extruded Mg-6Zn-l Y(wt.%)alloy reinforced by the I-phase has been *** promotes the formation of the intermetallic Mg6Zn3Ca2 phase instead of 1-phase,which results in a noticeable improvement of the yield strength and ultimate tensile strength of the alloy above 100℃.The strength of the alloys was analysed taking into account the contribution due to the grain size,the crystallographic texture and the volume fraction and nature of second phase *** situ synchrotron radiation diffraction experiments have been used to evaluate the load partitioning between the magnesium matrix and the second phase particles(1-and MgeZgCa?phases)in both *** load transfer from the magnesium matrix towards the MgeZihCa?phase is markedly more effective than that for the I-phase over the entire temperature range,especially at 200°C,temperature at which the reinforcement effect of the I-phase is null.

关键词： Magnesium alloys I-phase Synchrotron radiation diffraction High temperature mechanical properties.

Role of potassium in acid secretion

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2005年第34期11卷 5259-5265页

作者： john p Geibel professor of Surgery and Cellular and Molecular physiology Director of Surgical Research Yale University School of Medicine CT United States

potassium (K+) ions are critical for the activation and catalytic cycle of the gastric H+,K+-ATpase, resulting in the secretion of hydrochloric acid into the parietal cell canaliculus. As both symptom, severity and esophageal mucosal damage in gastro-esophageal reflux disease (GERD) are related to the degree of acid exposure, K+ is a logical target for approaches to inhibit acid *** probable K+ binding site on the gastric H+,K+-ATpase has recently been described and studies are elucidating how K+ activates the enzyme. K+ channels in the apical membrane of the parietal cell are implicated in the recycling of K+ and, to date, three potential K+ channels (KCNQ1, Kir2.1 and Kir4.1) have been identified. The channels represent theoretical sites for agents to control acid secretion but it will be difficult to develop selective blockers. An alternative strategy is to prevent K+ from activating gastric H+,K+-ATpase; the potassiumcompetitive acid blocker (p-CAB) class inhibits acidsecretion by binding at or near the K+ binding *** research is further defining the role of K+ in the functioning of the gastric H+,K+-ATpase, as well as determining the clinical utility of agents directed toward this important cation.

关键词： Gastric H%+,K^+-ATpase HCl parietal cell potassium potassium channel potassium channel blocker potassium-competitive acid blocker

The theory of interaction between wave and basic flow

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese physics B 2008年第3期17卷 1138-1146页

作者：冉令坤 john p.Boyd Laboratory of Cloud-precipitation physics and Severe Storms (LACS) Institute of Atmospheric PhysicsChinese Academy of Sciences Department of Atmospheric Oceanicand Space ScienceUniversity of MichiganAnn ArborMichiganUSA

This paper investigates the interaction between transient wave and non-stationary and non-conservative basic flow. An interaction equation is derived from the zonally symmetric and non-hydrostatic primitive equations in Cartesian coordinates by using the Momentum-Casimir method. In the derivation, it is assumed that the transient disturbances satisfy the linear perturbation equations and the basic states are non-conservative and slowly vary in time and space. The diabatic heating composed of basic-state heating and perturbation heating is also introduced. Since the theory of wave-flow interaction is constructed in non-hydrostatic and ageostrophic dynamical framework, it is applicable to diagnosing the interaction between the meso-scale convective system in front and the background flow. It follows from the local interaction equation that the local tendency of pseudomomentum wave-activity density depends on the combination of the perturbation flux divergence second-order in disturbance amplitude, the local change of basic-state pseudomomentum density, the basic-state flux divergence and the forcing effect of diabatic heating. Furthermore, the tendency of pseudomomentum wave-activity density is opposite to that of basic-state pseudomomentum density. The globally integrated basic-state pseudomomentum equation and wave-activity equation reveal that the global development of basic-state pseudomomentum is only dominated by the basic-state diabatic heating while it is the forcing effect of total diabatic heating from which the global evolution of pseudomomentum wave activity results. Therefore, the interaction between the transient wave and the non-stationary and non-conservative basic flow is realized in virtue of the basic-state diabatic heating.

关键词： wave flow interaction pseudomomentum wave activity diabatic heating Momentum Casimir method

Energy Gap Dependence on Mn Content in a Diluted Magnetic Quantum Dot

在线全文

学校读者我要写书评

暂无评论

Chinese physics Letters 2011年第4期28卷 201-204页

作者： p.Nalini A.john peter Department of physics Yadava College Govindarajan CampusThiruppalaiMadurai-625014India Department of physics Govt.Arts and Science CollegeMelur-625106MaduraiIndia

positively charged donor exciton binding energy is computed as a function of quantum-dot size within the single band effective mass approximation for different Mn contents in Cd_(1)−x_(𝑥in)Mn_(x𝑥in)Te/Cd_(1−xout)𝑥outMn_(xout)𝑥*** exciton bound polaron is computed for 0≤x𝑥≤0.08,on the Mn mole *** determine the energy gap using the mean field approximation and incorporate the exchange interaction between the carrier and the magnetic *** interband emission energy is studied with the height and radius of the cylindrical quantum ***-band anisotropy is included in our theoretical model using different hole masses in different spatial *** polaronic shifts as functions of quantum-dot radius and Mn concentration are estimated using the mean field *** is found that(i)the energy gap depends on the Mn mole fraction,(ii)it increases linearly with an increase in Mn content,and(iii)the effect is more pronounced for a narrow dot,showing the quantum size *** results are in good agreement with other recently published reports.

关键词： theory quantum radius

A Method of Characterizing Radio Signal Space for Wireless Device Localization

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Tsinghua Science and Technology 2015年第4期20卷 385-408页

作者： john-Austen Francisco Richard p.Martin Department of Computer Science Rutgers University

In this work we present a novel approach for describing radio signal spaces for localization algorithms. We first introduce a new metric, the Discretely Distributed Log-H61der Metric （DDLHM）. The DDLHM is designed to characterize the type and degree of signal distortion relative to Iognormal signal-to-distance path models. We first show how the DDLHM can describe and discriminate distortions in an exhaustive set of synthetic signal spaces. We then determine a reduced set of maximally diagnostic distortion parameters. Using only 4% of the maximal set of DDLHMs, we found the reduced set matches with an acceptable degree of error 95% of the time. Using the synthetic reduced set, we characterized a variety of wireless localization algorithms＇ behaviors to attenuation, bias, and multipath. We found algorithms made much different tradeoffs between best case and average case error. We then use the DDLHM to identify distortion types in three different physical environments using measured 802.11 signal strengths, and predict the positioning performance of several localization algorithms. Our approach predicts average localization error to within 2 meters of the observed average error.

关键词： radio propgation 802.11 WiFi

Chebyshev Spectral Methods and the Lane-Emden problem

在线全文

学校读者我要写书评

暂无评论

Numerical Mathematics(Theory,Methods and Applications) 2011年第2期4卷 142-157页

作者： john p.Boyd Department of Atmospheric Oceanic and Space ScienceUniversity of Michigan2455 Hayward AvenueAnn ArborMI 48109-2143USA

The three-dimensional spherical polytropic Lane-Emden problem is yr r+(2/r)y_(r)+y^(m)=0,y(0)=1,y_(r)(0)=0 where m∈[0,5]is a constant *** domain is r∈[0,ξ]whereξis the first root of y(r).We recast this as a nonlinear eigenproblem,with three boundary conditions andξas the eigenvalue allowing imposition of the extra boundary condition,by making the change of coordinate x≡r/ξ:y_(xx)+(2/x)y_(x)+ξ^(2) y^(m)=0,y(0)=1,y_(x)(0)=0,y(1)=*** find that a Newton-Kantorovich iteration always converges from an m-independent starting point y^((0))(x)=cos([π/2]x),ξ^((0))=*** apply a Chebyshev pseudospectral method to discretize *** Lane-Emden equation has branch point singularities at the endpoint x=1 whenever m is not an integer;we show that the Chebyshev coefficients are a_(n)∼constant/n^(2m+5) as n→∞.However,a Chebyshev truncation of N=100 always gives at least ten decimal places of accuracy—much more accuracy when m is an *** numerical algorithm is so simple that the complete code(in Maple)is given as a one page table.

关键词： Lane-Emden Chebyshev polynomial pseudospectral

A Fourier Companion Matrix (Multiplication Matrix) with Real-Valued Elements: Finding the Roots of a Trigonometric polynomial by Matrix Eigensolving

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Numerical Mathematics(Theory,Methods and Applications) 2013年第4期6卷 586-599页

作者： john p.Boyd Department of Atmospheric Oceanic&Space ScienceUniversity of Michigan2455 Hayward AvenueAnn Arbor MI 48109USA

We show that the zeros of a trigonometric polynomial of degree N with the usual(2N+1)terms can be calculated by computing the eigenvalues of a matrix of dimension 2N with real-valued elements M_(jk).This matrix M is a multiplication matrix in the sense that,after first defining a vector φwhose elements are the first 2N basis functions,Mφ=2cos(t)φ.This relationship is the eigenproblem;the zeros tk are the arccosine function of λ_(k)/2 where theλk are the eigenvalues of *** dub this the“Fourier Division Companion Matrix”,or FDCM for short,because it is derived using trigonometric polynomial *** show through examples that the algorithm computes both real and complex-valued roots,even double roots,to near machine precision accuracy.

关键词： Fourier series trigonometric polynomial rootfinding secular companion matrix