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红树林真菌Hypocrea lixii Vb1的抗癌及抗菌活性(英文)

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中国天然药物 2012年第1期10卷 77-80页

作者： b.valentin bhimba D.A.Agnel Defora Franco Jibi Merin Mathew Geena Mary Jose Elsa Lycias Joel M.Thangaraj Department of biotechnology Sathyabama UniversityChennai-600 119India CAS in Marine biology Annamalai UniversityParangipettaiChidambaramTamilNaduIndia

AIM:Mangrove is one of the oldest living tree species and its leaves are among the most extensively studied botanicals in use *** research throughout the world has found evidence to support the fact that its foliar extracts have great potential against human microbial *** study highlights the isolation of foliar fungi from Rhizophora mucronata,Avicenna officialis and Avicenna ***:It was isolated in Sabouroud's Dextrose Agar and mass cultivation was done in Sabouroud's Dex-trose ***:The ethyl acetate extract showed maximum antibacterial activity which inturn checked for different concentra-tion against bacterial pathogens and anticancer activity for Hep2 and MCF7 cell line in *** DNA was isolated from the fungi and the ITS region of 5.8 s RNA was sequenced and assigned to new species as they are separated from the type strains phylogenetic neighbors by sequence ***:This preliminary screening of fungal endophytes revealed their potential to yield potent bioactive compounds for drug discovery programmes.

关键词：生物工程学仿生学基因工程酶工程

Isolation and characterization of secondary metabolites from the mangrove plant Rhizophora mucronata

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Asian Pacific Journal of Tropical Medicine 2010年第8期3卷 602-604页

作者： Elsa Lycias Joel valentin bhimba Institute for Environmental Research and Social Education(IERSE) NagercoilKanyakumari District Research Scholar Department of BiotechnologySathyabama UniversityRajiv Gandhi SalaiChennai-119 Department of biotechnology Sathyabama UniversityRajiv Gandhi SalaiChennai-119

Objective:To evaluate the antibacterial activity of foliar extracts of Rhizophora mucronnata(R. mucronata) against pathogens belonging to human origin and to identify the compound hitherto unprecedented in nature by GC-MS ***:Soxhlet extraction method was used to get the corresponding extracts of ethanol,petroleum ether,acetone,methanol and ethyl *** antimicrobial activities of the organic solvent extracts on the various test organisms using agar well diffusion technique were carried *** acetate extract exhibited promising antimicrobial activity and hence minimum inhibitory concentration(MIC) was performed for the *** chromatography was done for partial purification of crude extract and fractions were analyzed by ***:A column chromatographic fractionation of the extracts and further UV visible and GS-MS analysis suggested the active principle compound were a mixture of squalene(19.19%),n-Hexadecanoic acid(6.59%),phytol(4.74%).2-cyclohexane-l- one, 4-hydroxy-3,5,(4.20%) and oleic acid(2.88%).Conclusions:The results are good enough to serve to transform the practice of research in this sub field across a range of different benefit streams that include drug *** and large this type of structure analyses are most important as aids to more rational decision taking in safety models versus *** general,structural data provide prima facie support for drug hypothesis.

关键词： Antibacterial activity Secondary metabolite Rhizophora mucronata GC-MS

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

Antibacterial screening of silver nanoparticles synthesized by marine micro algae

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Asian Pacific Journal of Tropical Medicine 2010年第10期3卷 797-799页

作者： D Devina Merin S Prakash b valentine bhimba Department of biotechnology Udaya School of EngineeringUdaya NagarVellamodiAmmandivillai post-629204Kanyakumari DistrictTamil NaduIndia Department of biotechnology Sathyabama UniversityChennai-600 119TamilnaduIndia

Objective:To explore the biosynthesis of silver nanoparticles synthesized by marine microalgae. Methods:Marine microalgae was collected from Central Marine Fisheries Research Institute (CMFRI,tuticorin) and cultured in the *** nanoparticles synthesis were observed in normal and microwave irradiated microalgae and screened against human pathogens for the presence of ***:The presence of silver nanoparticle was confirmed by UV-Visible spectroscopy at 420 nm by the presence of plasmon *** confirmation was done by scanning electron microscope(SEM).Conclusions:These results not only provide a base for further research but are useful for drug development in the present and future.

关键词： Silver nanoparticle Marine microalgae Screening antimicrobials Synthesize

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

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

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

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

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