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Impacts of PI3K/protein kinase B pathway activation in reactive astrocytes: from detrimental effects to protective functions

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Neural Regeneration Research 2025年第4期20卷 1031-1041页

作者： Ramón Pérez-Núñez María Fernanda González Ana María Avalos Lisette Leyton Cellular Communication laboratory Programa de Biología Celular y MolecularCenter for Studies on ExerciseMetabolism and Cancer(CEMC)Instituto de Ciencias Biomédicas(ICBM)Facultad de MedicinaUniversidad de ChileSantiagoChile Advanced Center for Chronic Diseases(ACCDiS) Faculty of Chemical and Pharmaceutical Sciences&Faculty of MedicineUniversidad de ChileSantiagoChile Instituto de Ciencias Biomédicas Facultad de Ciencias de la SaludUniversidad Autónoma de ChileSantiagoChile

Astrocytes are the most abundant type of glial cell in the central nervous *** injury and inflammation,astrocytes become reactive and undergo morphological and functional *** on their phenotypic classification as A1 or A2,reactive astrocytes contribute to both neurotoxic and neuroprotective responses,***,this binary classification does not fully capture the diversity of astrocyte responses observed across different diseases and *** analysis has revealed that reactive astrocytes have a complex landscape of gene expression profiles,which emphasizes the heterogeneous nature of their *** actively participate in regulating central nervous system inflammation by interacting with microglia and other cell types,releasing cytokines,and influencing the immune *** phosphoinositide 3-kinase(PI3K)/protein kinase B(AKT)signaling pathway is a central player in astrocyte reactivity and impacts various aspects of astrocyte behavior,as evidenced by in silico,in vitro,and in vivo *** astrocytes,inflammatory cues trigger a cascade of molecular events,where nuclear factor-κB serves as a central mediator of the pro-inflammatory ***,we review the heterogeneity of reactive astrocytes and the molecular mechanisms underlying their *** highlight the involvement of various signaling pathways that regulate astrocyte reactivity,including the PI3K/AKT/mammalian target of rapamycin(mTOR),αvβ3 integrin/PI3K/AKT/connexin 43,and Notch/PI3K/AKT *** targeting the inactivation of the PI3K/AKT cellular signaling pathway to control reactive astrocytes and prevent central nervous system damage,evidence suggests that activating this pathway could also yield beneficial *** dual function of the PI3K/AKT pathway underscores its complexity in astrocyte reactivity and brain function *** review emphasizes the importance of employing astrocyte-exclusive models to underst

关键词： inflammation integrins neuroprotective neurotoxic phosphatidylinositol 3-kinase reactive astrocytes signal transduction Thy-1(CD90)

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Electronic structure of the rare-earth superstoichiometric dihydride GdH_(2.25)

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Rare Metals 2022年第8期41卷 2794-2799页

作者： Zahia Ayat Aomar Boukraa Abdelouahab Ouahab Bahmed Daoudi Fac.des Mathématiques et des sciences de la Matière Lab.Développement desénergies nouvelles et renouvelables dans les zones arides et sahariennesUniversity of Ouargla30000OuarglaAlgeria Département des sciences de la Matière Facultédes Sciences Exactes et des Sciences de la Nature et de la VieUniversitéMohamed Khider Biskra07000BiskraAlgeria

With the WIEN2 k simulation code,ab initio calculations of electronic structure and of equilibrium properties for the superstoichiometric rare-earth dihydride GdH_(2.25)using the full-potential linearized augmented plane-wave(FP-laPW)method within density functional theory(DFT)in generalized gradient approximation(GGA)were *** lattice parameter,bulk modulus,pressure derivative,density of states(DOS)and energy band structures were *** GGA-optimized lattice parameter agrees much better with the experimental findings than the local density approximation(LDA)*** non-negligible electronic DOS at Fermi level confirms that GdH_(2.25)has a metallic *** Fermi energy(E_(F))falls at a level where most of the states are rare-earth 5 d conduction states while negligible contributions of both interstitial(tetrahedral and octahedral)H s states are observed near *** is found that hybridization exists between s electronic orbital of both interstitial H atoms and d electronic orbitals of Gd.

关键词： Rare-earth dihydrides GdH_(2.25) density functional theory Ab initio calculations WIEN2k

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Influence of nitrogen sources on growth and mycotoxin production by isolates of Pyrenophora tritici-repentis from wheat

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The Crop Journal 2016年第2期4卷 119-128页

作者： Noureddine Bouras Michael D.Holtz Reem Aboukhaddour Stephen E.Strelkov department of Agricultural Food and Nutritional Science410 Agriculture/Forestry CentreUniversity of Alberta laboratoire de Biologie des Systemes Microbiens(LBSM) Ecole Normale Superieure de KoubaAlgiersAlgeria departement de Biologie Faculte des Sciences de la Nature et de la Vie et Sciences de la TerreUniversite de Ghardaia Field Crop development Centre Alberta Agriculture and Food

The fungus Pyrenophora tritici-repentis(Died.) Drechs. infects the leaves and kernels of wheat,causing tan spot and red smudge, respectively. Isolates of P. tritici-repentis have been reported to be both phytopathogenic and mycotoxigenic. This research investigates the influence of nitrogen sources on growth and production of mycotoxins by eight different isolates of P. tritici-repentis. A synthetic agar medium(SAM) was used with different nitrogen sources, both inorganic [(NH4Cl, NH4NO3and(NH4)2SO4)] and organic(L-alanine, L-histidine, and L-lysine), at a concentration of 37.5 mmol L-1. Individual isolates exhibited different growth rates that varied according to the nitrogen source added to the medium. The choice of nitrogen source also had a major effect on production of the mycotoxins emodin, catenarin and islandicin. The highest concentrations of emodin, 54.40 ± 4.46 μg g-1, 43.07 ± 23.39 μg g-1and28.91 ± 4.64 μg g-1of growth medium, were produced on the complex medium(V8-potato dextrose agar) by the isolates Alg-H2, 331-2 and TS93-71 B, respectively. A relatively high concentration of emodin also was produced by isolates Az35-5(28.29 ± 4.71 μg g-1of medium)and TS93-71B(27.03 ± 4.09 μg g-1of medium) on synthetic medium supplemented with L-alanine. The highest concentrations of catenarin(174.54 ± 14.46 μg g-1and 104.87 ±6.13 μg g-1of medium) were recorded for isolates TS93-71 B and Alg-H2 on synthetic medium supplemented with L-alanine and NH4 Cl, respectively. The highest concentration of islandicin(4.64 ± 0.36 μg g-1medium) was observed for isolate 331-2 in the presence of L-lysine. There was not a close relationship between mycelial growth and mycotoxin production by the fungal isolates. This is the first report on the influence of nitrogen sources on the production of mycotoxins by P. tritici-repentis.

关键词： Catenarin Emodin Islandicin Nitrogen source Tan spot Triticum aestivum

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Geodynamic evolution of the Earth over the Phanerozoic:Plate tectonic activity and palaeoclimatic indicators

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Journal of Palaeogeography 2015年第2期4卷 167-188页

作者： Christian Vérard Cyril Hochard Peter O.Baumgartner Gérard M.Stampfli Université de lausanne (UNIL) Institut des Sciences de la Terre (ISTE)

During the last decades, numerous local reconstructions based on field geol- ogy were developed at the University of lausanne （UNIL）. Team members of the UNIL partici- pated in the elaboration of a 600 Ma to present global plate tectonic model deeply rooted in geological data, controlled by geometric and kinematic constraints and coherent with forces acting at plate boundaries. In this paper, we compare values derived from the tectonic model （ages of oceanic floor, production and subduction rates, tectonic activity） with a combination of chemical proxies （namely CO2, 87Sr/86Sr, glaciation evidence, and sea-level variations） known to be strongly in- fluenced by tectonics. One of the outstanding results is the observation of an overall decreas- ing trend in the evolution of the global tectonic activity, mean oceanic ages and plate velocities over the whole Phanerozoic. We speculate that the decreasing trend reflects the global cooling of the Earth system. Additionally, the parallel between the tectonic activity and CO2 together with the extension of glaciations confirms the generally accepted idea of a primary control of CO2 on climate and highlights the link between plate tectonics and CO2 in a time scale greater than 107 yr. last, the wide variations observed in the reconstructed sea-floor production rates are in contradiction with the steady-state model hypothesized by some.

关键词： geodynamic plate tectonics plate model Phanerozoic palaeoclimate CO2,strontium glaciation

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Geodesic equation in non-commutative gauge theory of gravity

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Chinese Physics C 2022年第10期46卷 193-206页

作者： Abdellah Touati Slimane Zaim laboratoire de Physique des Rayonnements et de leurs Interactions avec la Matiere departement de Physique Faculte des Sciences de la Matiere Universite de Batna-1Batna 05000Algeria departement de Physique Faculte des Sciences de la Matière Universitéde Batna-1Batna 05000Algeria

In this study,we construct a non-commtative gauge theory of the modified structure of the gravitational field using the Seiberg-Witten map and the general tetrad fields of Schwarzschild space-time to show that the noncommutative geometry removes the singularity at the origin of the black hole,thus obtaining a non-singular Schwarzschild black *** geodetic structure of this black hole presents new types of motion next to the event horizon within stable orbits that are not allowed by the ordinary Schwarzschild *** noncommutative periastron advance of the Mercury orbit is obtained,and with the available experimental data,we find a parameter of non-commutativity on the order of 10^(-25)s·kg^(-1).This result shows that the new fundamental length,√h■,is on the order of 10^(-31)m.

关键词： non-commutative geometry gauge gravity Schwarzschild space-time geodesic equation

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On stability behaviors of 5D M-theory black objects

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Communications in Theoretical Physics 2024年第5期76卷 94-101页

作者： Adil Belhaj Abderrahim Bouhouch departement de Physique Equipe des Sciences de la matiere et du rayonnementESMaR Faculte des SciencesUniversite Mohammed V de RabatRabatMorocco

Using N=2 supergravity formalism,we investigate certain behaviors of five-dimensional black objects from the compactification of M-theory on a Calabi-Yau *** manifold has been constructed as the intersection of two homogeneous polynomials of degrees(ω+2,1)and(2,1)in a product of two weighted projective spaces given by WP^(4)(ω,1,1,1,1)×P^(1).First,we determine the allowed electric charge regions of the BPS and non BPS black holes obtained by wrapping M2-branes on appropriate two cycles in such a proposed Calabi-Yau *** that,we calculate the entropy of these solutions which takes a maximal value corresponding to ω=1 defining the ordinary projective space P^(4).For generic values of ω,we show that the non BPS states are ***,we conduct a similar study of five-dimensional black *** the allowed magnetic charge regions of the BPS and non BPS black stringy solutions derived from M5-branes on dual divisors,we calculate the tension taking a minimal value for P^(4).By determining the recombination factor,we show that the non-BPS black string states are stable in the allowed regions in the magnetic charge space.

关键词： M-theory Calabi-Yau manifolds black holes black strings stability behaviors

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Structural,electronic,optical,and magnetic properties of Co-doped Cu2O

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Chinese Physics B 2017年第2期26卷 387-391页

作者： I Djabri T Rezkallah F Chemam laboratoire de la Physique Appliquee et Theorique Departement des Sciences de la matiere Universite Laarbi tebessi tebessa Algeri

We investigate the magnetic properties of Co-doped Cu_2O. We studied first the electronic and structural properties of Cu_2O using the optimization of the lattice constant which is 4.18 . The calculated gap is found between 0.825 eV and1.5 eV, these values are in good agreement with the experimental results. The Co atoms are inserted in Cu_2O by means of the density functional theory（DFT） using LSDA, LSDA ＋U, and LSDA ＋ MBJ approximations in the WIEN2 k code, based on the supercell model by setting up 12, 24, and 48 atoms in（1×1 × 2）,（1 × 2 × 2）, and（2 × 2×2） supercells respectively with one or two copper atoms being replaced by cobalt atoms. The energy difference between the ferromagnetic and antiferromagnetic coupling of the spins located on the substitute Co has been calculated in order to obtain better insight into the magnetic exchange coupling for this particular compound. The studied compound exhibits stable integer magnetic moments of 2 μBand 4 μBwhen it is doped with 2 atoms of Co. Optical properties have also been worked out. The results obtained in this study demonstrate the importance of the magnetic effect in Cu_2O.

关键词： Cu2O electronic structure magnetic properties optical properties

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Soliton excitations in a polariton condensate with defects

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Chinese Physics B 2018年第1期27卷 278-283页

作者： Abderahim Mahmoud Belounis Salem Kessal SNIRM laboratory Faculty of Physics Universite des Sciences et de la Technologie Houari Boumediene (USTHB)

To study soliton excitations in a polariton condensate with defects, we use the Gross-Pitaevskii equation and its hydrodynamic form. An extra term is added to take into account the non-equilibrium nature of the polariton condensate and the presence of defects. The reductive perturbation method transforms these hydrodynamic equations into a modified Korteweg-de Vries equation in the long wavelength limit. We linearize this equation and study the soliton linear excitations. We give an analytic expression of traveling excitations using the variation of constants method. In the more general form, we show numerically that the excitations are oscillations simultaneously hut in an opposite way. i.e., the amplitude and the width of the dark soliton oscillate

关键词： solitons polariton condensates reductive perturbation method

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On M-theory on real toric fibrations

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Communications in Theoretical Physics 2021年第8期73卷 67-74页

作者： A Belhaj H Belmahi M Benali S-E Ennadifi Y Hassouni Y Sekhmani Equipe des sciences de la matière et du rayonnement ESMaRDépartement de Physique Facultédes SciencesUniversitéMohammed V de RabatMorocco LHEP-MS Département de PhysiqueFaculte des SciencesUniversitéMohammed V de RabatMorocco

Borrowing ideas from elliptic complex geometry, we approach M-theory compactifications on real fibrations. Precisely, we explore real toric equations rather than complex ones exploited in F-theory and related dual models. These geometries have been built by moving real toric manifolds over real bases. Using topological changing behaviors, we unveil certain data associated with gauge sectors relying on affine lie symmetries.

关键词： real fibrations M-theory toric real manifolds affine lie symmetries

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3D palaeogeographic reconstructions of the Phanerozoic versus sea-level and Sr-ratio variations

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Journal of Palaeogeography 2015年第1期4卷 64-84页

作者： Christian Vérard Cyril Hochard Peter O.Baumgartner Gérard M.Stampfli Université de lausanne (UNIL) Institut des Sciences de la Terre (ISTE)Geopolis Ch–1015 Lausanne Switzerland

A full global geodynamical model over 600 million years （Ma） has been de- veloped at the University of lausanne during the past 20 years. We show herein how the 2D maps were converted into 3D （i.e., full hypsometry and bathymetry）, using a heuristic-based approach. Although the synthetic topography may be viewed as relatively crude, it has the advantage of being applicable anywhere on the globe and at any geological time. The model allows estimating the sea-level changes throughout the Phanerozoic, with the possibility, for the first time, to flood accordingly continental areas. One of the most striking results is the good correlation with ＂measured＂ sea-level changes, implying that long-term variations are predominantly tectonically-driven. Volumes of mountain relief are also estimated through time and compared with strontium isotopic ratio （Sr-ratio）, commonly thought to reflect mountain belt erosion. The tectonic impact upon the general Sr-retio trend is shown herein for the first time, although such influence was long been inferred.

关键词： palaeogeography reconstruction hypsometry bathymetry sea-level Sr-ratio tectonic-climate relationship

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