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Segmental closure of the Mongol-Okhotsk Ocean:Insight from detrital geochronology in the East Transbaikalia basin

Geoscience Frontiers 2022年第1期13卷 15-27页

作者： Anastasia V.Arzhannikova Elena I.Demonterova Marc Jolivet Ekaterina A.Mikheeva Alexei V.Ivanov Sergey G.Arzhannikov valentin b.khubanov Vadim S.Kamenetsky Institute of the Earth’s Crust Russian Academy of SciencesSiberian BranchIrkutskRussia Laboratoire Géosciences Rennes CNRS-UMR6118Universitéde RennesRennesFrance Geological Institute Russian Academy of SciencesSiberian BranchUlan-UdeRussia

The Late Paleozoic–Early Mesozoic Mongol-Okhotsk Ocean extended between the Siberian and Amur–North China *** timing and modalities of the oceanic closure are widely *** is largely accepted that the ocean closed in a scissor-like manner from southwest to northeast(in modern coordinates),though the timing of this process remains *** studies have shown that both western(West Transbaikalia)and eastern(Dzhagda)parts of the ocean closed almost simultaneously at the Early–Middle Jurassic ***,little information on the key central part of the oceanic suture zone is *** performed U-Pb(LA-ICP-MS)dating of detrital zircon from wellcharacterized stratigraphic sections of the central part of the Mongol-Okhotsk suture *** include the initial marine and final continental sequences of the East Transbaikalia basin,deposited on the northern Argun-Idemeg terrane *** provide new stratigraphic ages for the marine and continental *** revised chronostratigraphy allows assigning an age of~165–155 Ma,to the collisionrelated flexure of the northern Argun-Idemeg terrane and the development of a peripheral foreland *** collisional process took place 5 to10 million years later than in the western and eastern parts of the *** demonstrate that the northern Argun-Idemeg terrane was the last block to collide with the Siberian continent,challenging the widely supported scissor-like model of closure of the MongolOkhotsk *** segments of the ocean closed independently,depending on the initial shape of the paleo continental margins.

关键词： Detrital zircon U-Pb geochronology Mongol-Okhotsk collision East Transbaikalian basin

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Late Mesozoic topographic evolution of western Transbaikalia:Evidence for rapid geodynamic changes from the Mongol-Okhotsk collision to widespread rifting

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Geoscience Frontiers 2020年第5期11卷 1695-1709页

作者： A.V.Arzhannikova E.I.Demonterova M.Jolivet S.G.Arzhannikov E.A.Mikheeva A.V.Ivanov V.b.khubanov L.A.Pavlova Institute of the Earth’s Crust Russian Academy of SciencesSiberian BranchIrkutskRussia Laboratoire Geosciences Rennes CNRS-UMR6118Universite de RennesRennesFrance Geological Institute Russian Academy of SciencesSiberian BranchUlan-UdeRussia A.P.Vinogradov Institute of Geochemistry Siberian Branch of the Russian Academy of SciencesIrkutskRussia

The Mesozoic geodynamic evolution of Transbaikalia has been largely controlled by the scissors-like closure of the Mongol-Okhotsk Ocean that separated Siberia from Mongolia-North China *** the oceanic closure,the tectonic evolution of that region was characterized by collisional uplift and subsequent extension that gave rise to the formation of metamorphic core *** complex tectonic setting prevailed simultaneously between 150 Ma and 110 Ma both in Transbaikalia,North Mongolia,and within the North China *** paleobotanical and paleontological data show that the oldest Mesozoic basins had formed in western Transbaikalia before the estimated age of extension *** no precise geochronological age is available for the onset of extension in *** Tugnuy basin,as probably the oldest Mesozoic basin in western Transbaikalia,is a key obj ect to date the onset of extension and following changes in tectonic *** this study,U-Pb(LA-ICP-MS)dating of detrital zircons from three key Jurassic sediment formations of the Tugnuy basin are used to identify the potential source areas of the sediments,understand the changes in sediment routing and provide insights on the topographic evolution of western *** results show several significant changes in tectonic regime after the closure of the Mongol-Okhotsk Ocean.A wide uplifted plateau formed during the closure of the Mongol-Okhotsk Ocean,determining the Early Jurassic drainage system reaching the AngaraVitim batholith to the north and shedding sediments to the continental margin to the *** following collisional event at the end of the Early Jurassic led to the uplift of the collision zone,which partially inverted the drainage system toward the North.A strike-slip displacement induced by the oblique collision initiated some of the early Transbaikalian depressions,such as the Tugnuy basin at about 168 Ma.A phase of basin inversion,marked by folding and ero

关键词： U–Pb detrital zircons dating Topographic evolution Mongol–Okhotsk collision Transbaikalia

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The role of tangential velocity in explosive initiation by fragment impact

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Defence Technology（防务技术） 2022年第12期18卷 2190-2197页

作者： Vitaly Leus Roy Ceder valentin Ognev Meir Mayseless RAFAEL ballistic Center P.O.Box 2250HaifaIsrael Faculty of Engineering Sciences Ben-Gurion University of the NegevBeer-Sheva84105Israel

An initiation study is presented in which we examine the effect of the normal and the tangential velocity components of a fragment that impacts a covered and a bare Comp-b explosive. The study is based on calibrated numerical Lagrangian simulations using the LS-Dyna hydrocode. A special procedure was developed to present the estimated initiation point and the shock wave transition into detonation for various impact angles. The influence of the fragment strength and the steel cover thickness on the detonation threshold were also examined. The velocity threshold results are presented and used to modify the Jacobs-Roslund initiation model.

关键词： High explosive initiation Lee-tarver Jacobs-roslund Fragment

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Non-Adiabatic Phonon Dispersion of Metallic Single-Walled Carbon Nanotubes

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Nano Research 2010年第11期3卷 822-829页

作者： valentin N.Popov Philippe Lambin Faculty of Physics University of SofiaBG-1164 SofiaBulgaria Research Center in Physics of Matter and Radiation Facultés Universitaires Notre Dame de la PaixB-5000 NamurBelgium

Non-adiabatic effects can considerably modify the phonon dispersion of low-dimensional metallic ***,these effects are studied for the case of metallic single-walled carbon nanotubes using a perturbative approach within a density-functional-based non-orthogonal tight-binding *** adiabatic phonon dispersion was found to have logarithmic Kohn anomalies at the brillouin zone center and at two mirror points inside the *** obtained dynamic corrections to the adiabatic phonon dispersion essentially modify and shift the Kohn anomalies as exemplified in the case of nanotube(8,5).Large corrections have the longitudinal optical phonon,which gives rise to the so-called G-band in the Raman spectra,and the carbon hexagon breathing *** results obtained for the G-band for all nanotubes in the diameter range from 0.8 to 3.0 nm can be used for assignment of the high-frequency features in the Raman spectra of nanotube samples.

关键词： Nanotube phonons G band tight-binding model

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busting the efficiency of SAPO-34 catalysts for the methanol-to-olefin conversion by post-synthesis methods

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Chinese Journal of Chemical Engineering 2020年第8期28卷 2022-2027页

作者： Guoju Yang Ji Han Yujun Huang Xiaoxin Chen valentin Valtchev State Key Laboratory of Inorganic Synthesis and Preparative Chemistry College of ChemistryJilin University2699 Qianjin StreetChangchun 130012China International Center of Future Science Jilin University2699 Qianjin StreetChangchun 130012China Normandie Univ ENSICAENUNICAENCNRSLaboratoire Catalyse et Spectrochimie6 Marechal Juin14050 CaenFrance

As an effective non-petroleum based process for producing light olefins, the methanol-to-olefin(MTO) route has become an indispensable alternative to the industrial production of light olefins. The silicoaluminophosphate SAPO-34 zeolite(CHA-type structure) has proven to be an efficient industrial catalyst for the production of ethylene and propylene by the MTO reaction. However, the inherent structure and related diffusion limitations of SAPO-34 limit the mass transport and thus cause rapid deactivation of the catalyst. Fabrication of hierarchical SAPO-34 zeolite is one of the most effective strategies to address the intrinsic diffusion limitation. As simple, inexpensive, and efficient approach, the post-synthetic route has attracted considerable attention and widely used to introduce secondary meso-/macropores into the microporous SAPO-34 material. Significant effort has been dedicated to the development of post-synthesis strategies to prepare hierarchical SAPO-34 zeolite, thereby enhancing its catalytic performance in the MTO process. This mini-review addresses the post-synthesis preparation of hierarchical SAPO-34 catalysts and their MTO performance. Furthermore, some current problems and prospects of the post-synthesis route to hierarchical SAPO-34 catalysts are also revised. We expect this minireview to inspire the more efficient preparation of hierarchical SAPO-34 catalysts for the MTO process.

关键词： Zeolites SAPO-34 Post-synthesis treatment Hierarchical MTO

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Antibacterial activity and characterization of secondary metabolites isolated from mangrove plant Avicennia officinalis

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Asian Pacific Journal of Tropical Medicine 2010年第7期3卷 544-546页

作者： valentin bhimba b J Meenupriya Elsa Lycias Joel D Edaya Naveena Suman kumar M Thangaraj Department of biotechnology Sathyabama University Rajiv Gandhi SalaiChennai-119Tamil naduIndia Institute for Environmental Research and Social Education Nagercoil Kanyakumari DistrictIndia Research Scholar Department of BiotechnologySathyabama UniversityRajiv Gandhi Salai.Chennai-119Tamil naduIndia CAS in Marine biology Annamalai UniversityParangipettai-608 502Cuddalore DistrictIndia

Objective:To explore antibacterial activity and characterization of secondary metabolites isolated from mangrove plant Avicennia officinalis(***).Methods:In the present study the leaf extracts of *** were examined for its antibacterial potential using five different solvents against some reference strains of human pathogenic bacteria for the crude *** activity was observed for ethyl acetate and hence different concentrations like 15μL,25μL,and 50μL of ethyl extracts was checked for its antibacterial *** purification of crude extract was carried by column chromatography and fractions were analyzed using gas chromatography-mass spectrometry(GC-MS) to identify ***:The crude ethyl acetate extracts of *** showed remarkable antibacterial activity with zones of inhibition of 13 mm against Eschericia coli(***) and 11 mm against Staphylococcus aureus (***).Fraction 13(ethyl acetate:methanol= 8:2) as the most potent one against with the minimal inhibitory concentration of 30 mm against *** and 25 mm against *** GCMS resultsof active column fraction(F13) revealed that the active principals were a mixture of hydroxy- 4 methoxybenzoic acid,diethyl phthalate,oleic ***:The leaf extracts with proven antibacterial effects can clearly be directed towards cancer treatment as to inhibiting cancer cell *** limited number of test organisms owes to a constraint of ***,the effect of strong bursts of leaf extracts on human pathogenic bacteria should further be tested on a wide range of test organisms.

关键词： Mangrove Avicennia officinalis Antibacterial GC-MS

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Ocular surface squamous neoplasia resistant to topical interferon alpha 2b in a patient with follicular lymphoma

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International Journal of Ophthalmology(English edition) 2021年第7期14卷 1122-1124页

作者： valentin Huerva Magi Vilaltella Department of Ophthalmology University Hospital Arnau de VilanovaLleida 25198Spain School of Medicine University of Lleida(UdL)Lleida 25198Spain biomedical Research Institute of Lleida(IRb) Lleida 25198Spain

Dear Editor,Treatment for ocular surface squamous neoplasia(OSSN)includes topical mitomycin C(MMC),5-fluorouracil(5-FU)and interferon(IFN)-alpha 2b eyedrops[1-2].Compared to other treatments,such as mitomycin C(MMC),I... 详细信息

关键词： interferon squamous neoplasia

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Adhesion and friction in hard and soft contacts: theory and experiment

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Friction 2021年第6期9卷 1688-1706页

作者： valentin L.POPOV Qiang LI Iakov A.LYASHENKO Roman POHRT Technische Universität berlin Berlin 10623Germany National Research Tomsk State University Tomsk 634050Russia Sumy State University Sumy 40007Ukraine

This paper is devoted to an analytical,numerical,and experimental analysis of adhesive contacts subjected to tangential *** particular,it addresses the phenomenon of instable,jerky movement of the boundary of the adhesive contact zone and its dependence on the surface *** argue that the"adhesion instabilities"with instable movements of the contact boundary cause energy dissipation similarly to the elastic instabilities *** leads to different effective works of adhesion when the contact area expands and *** effect is interpreted in terms of“friction”to the movement of the contact *** consider two main contributions to friction:(a)boundary line contribution and(b)area *** normal and rolling contacts,the only contribution is due to the boundary friction,while in sliding both contributions may be *** boundary contribution prevails in very small,smooth,and hard contacts(as e.g.,diamond-like-carbon(DLC)coatings),while the area contribution is prevailing in large soft *** suggest that the friction due to adhesion instabilities is governed by"Johnson parameter".Experiments suggest that for soft bodies like rubber,the stresses in the contact area can be characterized by a constant critical *** were carried out using a setup allowing for observing the contact area with a camera placed under a soft transparent rubber *** contacts show a great variety of instabilities when sliding with low velocity–depending on the indentation depth and the shape of the contacting *** instabilities can be classified as"microscopic"caused by the roughness or chemical inhomogeneity of the surfaces and"macroscopic"which appear also in smooth *** latter may be related to interface waves which are observed in large contacts or at small indentation *** simulations were performed using the boundary Element Method(bEM).

关键词： adhesion friction adhesion hysteresis boundary Element Method(bEM) hard solids soft matter

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Therapeutic potential of mesenchymal stem cells in the treatment of acute liver failure

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World Journal of Gastroenterology 2022年第28期28卷 3627-3636页

作者： Carl Randall Harrell Dragica Pavlovic valentin Djonov Vladislav Volarevic Regenerative Processing Plant LLC Palm HarborFL 34176United States Department of Genetics Faculty of Medical SciencesUniversity of KragujevacKragujevac 34000Serbia Institute of Anatomy University of BernBern 3012Switzerland Department of Medical Genetics and Microbiology and Immunology Faculty of Medical SciencesUniversity of KragujevacKragujevac 34000Serbia

Acute liver failure(ALF)is a severe and life-threatening condition in which rapid deterioration of liver function develops in a patient who has no preexisting liver *** stem cells(MSCs)are immunoregulatory stem cells which are able to modulate phenotype and function of all immune cells that play pathogenic role in the development and progression of *** in juxtacrine and paracrine manner attenuate antigen-presenting properties of dendritic cells and macrophages,reduce production of inflammatory cytokines in T lymphocytes,suppress hepatotoxicity of natural killer T(NKT)cells and promote generation and expansion of immunosuppressive T,b and NKT regulatory cells in acutely inflamed *** to their nano-sized dimension and lipid envelope,intravenously injected MSC-derived exosomes(MSC-Exos)may by-pass all biological barriers to deliver MSC-sourced immunoregulatoy factors directly into the liver-infiltrated immune cells and injured *** obtained by us and others revealed that intravenous administration of MSCs and MSC-Exos efficiently attenuated detrimental immune response and acute inflammation in the liver,suggesting that MSCs and MSC-Exos could be considered as potentially new remedies in the immunotherapy of *** this review,we emphasize the current knowledge about molecular and cellular mechanisms which are responsible for MSC-based modulation of liver-infiltrated immune cells and we discuss different insights regarding the therapeutic potential of MSCs in liver regeneration.

关键词： Mesenchymal stem cells Acute liver failure Therapy Immunomodulation Regeneration

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Principal Denudation Processes and Their Contribution to Fluvial Suspended Sediment Yields in the Upper Yangtze River basin and Volga River basin

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Journal of Mountain Science 2015年第1期12卷 101-122页

作者： valentin Golosov ZHANG Xin-bao HE Xiu-bin TANG Qiang ZHOU Ping Key Laboratory of Mountain Surface Processes and Ecological Regulation Institute of Mountain Hazards and Environment Chinese Academy of Sciences Faculty of Geography Moscow State University Kazan (Volga region) State University State Key Laboratory of Urban and Regional Ecology Research Center for Ecoenvironment Sciences Chinese Academy of Sciences

This paper synthesized the principal land denudation processes and their role in determining riverine suspended sediment yields(SSY) in two typical geographical environments of the Upper Yangtze River basin in China and the Volga River basin in Eastern Europe. In the Upper Yangtze River basin, natural factors including topography, climate,lithology and tectonic activity are responsible for the spatial variation in the magnitude of denudation *** disturbances have contributed to the temporal changes of soil erosion and fluvial SSY during the past decades. On one hand, land use change caused by deforestation and land reclamation has played an important role in the acceleration of sediment production from the central hilly area and lower Jinsha catchment; On the other hand, diverse soil conservation practices(e.g., reforestation,terracing) have contributed to a reduction of soil erosion and sediment production since the late 1980 *** was difficult to explicitly decouple the effect of mitigation measures in the Lower Jinsha River basindue to the complexity associated with sediment redistribution within river channels(active channel migration and significant sedimentation). The whole basin can be subdivided into seven sub-regions according to the different proportional inputs of principal denudation processes to riverine SSY. In the Volga River basin, anthropogenic sheet, rill and gully erosion are the predominant denudation processes in the southern region, while channel bank and bed erosion constitutes the main source of riverine suspended sediment flux in the northern part of the basin. Distribution of cultivated lands significantly determined the intensity of denudation *** relief characteristics also considerably influence soil erosion rates and SSY in the southern Volga River basin. Lithology, soil cover and climate conditions determined the spatial distribution of sheet, rill and gully erosion intensity, but they play a secondary role in SSY s

关键词： Land denudation Anthropogenicdisturbance Suspended sediment yield UpperYangtze River Volga River

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