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Magnetooptics of non-Kramers Eu^(3+) ions in garnets:analysis complemented by crystal-field splitting modeling calculations

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Journal of Rare Earths 2013年第9期31卷 837-842页

作者： Uygun V.Valiev john b.Gruber Anvar K.Mukhammadiev Vasiliy O.Pelenovich 付德君 Gary W.burdick Faculty of Physics National University of Uzbekistan Department of Physics and Astronomy The University of Texas at San Antonio School of Physics and Technology Wuhan University Department of Physics Andrews University

Spectra of absorption, luminescence, magnetic circular dichroism （MCD）, and magnetic circular polarization of lumines- cence （MCPL） in Gd3Ga5O12：Eu3＋ and Eu3Ga3O12 garnets were studied within the visible spectral range at 300 K. Analysis of the spectral and temperature dependences of the magnetooptical and optical spectra made it possible to identify the magneto-dipole （MD） and electro-dipole （ED） 4f→4f transitions occurring between Stark sublevels of the 7FJ （J=1, 2） and 5D0 multiplets in Eua＋-containing garnet structures. Quantum mechanical ＂mixing＂ had significant influence on quasi-degenerate states of the non-Kramers rare-earth Eu3＋ ion for Eu3GasOl2 in MCD due to forbidden MD transition 7F1→SD0 and for GdaGasOiE：EU3＋ in MCPL due to MD 4f→4f transition 5Do→7F1 and forced ED-transition 5Do→7F2. A parameterized Hamiltonian defined to operate within the entire 4f（6） ground electronic configuration of Eu3＋ ion was used to model the experimental Stark levels, including their irreducible rep- resentations and wavefunctions. The crystal-field parameters were determined through a Monte-Carlo method in which nine in- dependent crystal-field parameters, bkq, were given random starting values and optimized using standard least-squares fitting between calculated and experimental levels. The final fitting standard deviation between 57 calculated-to-experimental levels was 0.73 meV.

关键词： : magnetic circular dichroism magnetic circular polarization luminescence adsorption garnet non-Kramers ion rare earths

Visual Prostheses: Technological and Socioeconomic Challenges

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Engineering 2015年第3期1卷 288-291页

作者： john b.Troy biomedical Engineering Department Northwestern UniversityEvanston

Visual prostheses are now entering the clinical marketplace. Such prostheses were originally targeted for patients suff ering from blindness through retinitis pigmentosa(RP). However, in late July of this year, for the first time a patient was given a retinal implant in order to treat dry agerelated macular degeneration. Retinal implants are suitable solutions for diseases that attack photoreceptors but spare most of the remaining retinal neurons. For eye diseases that result in loss of retinal output, implants that interface with more central structures in the visual system are needed. The standard site for central visual prostheses under development is the visual cortex. This perspective discusses the technical and socioeconomic challenges faced by visual prostheses.

关键词： neuroprostheses vision eye disease restoration of function rehabilitation

Effects and mechanisms of silibinin on human hepatoma cell lines

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World Journal of Gastroenterology 2007年第40期13卷 5299-5305页

作者： john J Lah Division of Gastroenterology University of CaliforniaIrvine Medical Center101 The City DriveBuilding 53Suite 113OrangeCA 92868United States

AIM： To investigate in vitro effects and mechanisms of silibinin on hepatocellular carcinoma （HCC） cell growth, METHODS： Human HCC cell lines were treated with different doses of silibinin. The effects of silibinin on HCC cell growth and proliferation, apoptosis, cell cycle progression, histone acetylation, and other related signal transductions were systematically examined. RESULTS： We demonstrated that silibinin significantly reduced the growth of HUH7, HepG2, Hep3b, and PLC/PRF/5 human hepatoma cells. Silibinin-reduced HuH7 cell growth was associated with significantly up- regulated p21/CDK4 and p27/CDK4 complexes, down- regulated Rb-phosphorylation and E2F1/DP1 complex. Silibinin promoted apoptosis of HuH7 cells that was associated with down-regulated survivin and upregulated activated caspase-3 and -9. Silibinin＇s antiangiogenic effects were indicated by down-regulated metalloproteinase-2 （MMP2） and CD34. We found that silibinin-reduced growth of HuH7 cells was associated with increased activity of phosphatase and tensin homolog deleted on chromosome ten （PTEN） and decreased p-Akt production, indicating the role of PTEN/ PI3K/Akt pathway in silibinin-mediated anti-HCC effects. We also demonstrated that silibinin increased acetylation of histone H3 and H4 （AC-H3 and AC-H4）, indicating a possible role of altered histone acetylation in silibininreduced HCC cell proliferation. CONCLUSION： Our results defined silibinin＇s in vitro anti-HCC effects and possible mechanisms, and provided a rationale to further test silibinin for HCC chemoprevention.

关键词： Hepatocellular carcinoma HuH7 cells Silibinin Chemoprevention Cell cycle Cell cycleprogression Apoptosis Acetylation of histone

Testing discrete symmetries at a super τ-charm factory

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Frontiers of physics 2016年第1期11卷 17-25页

作者： Adrian john bevan Particle Physics Research Centre Queen Mary University of London Mile End Road London E1 4NS UK

Tests of discrete symmetry violation have played an important role in understanding the structure of weak interactions in the Standard Model of particle physics. Historically, these measurements have been extensively performed in experiments with large samples of K and b mesons. A high luminosity τ-charm facility presents physicists with the opportunity to comprehensively explore discrete symmetry violation and test the Standard Model using τ leptons, charm mesons, and charmed baryons. This paper discusses several possible measurements for a future T-charm factory.

关键词： discrete symmetries P C T CP CPT violation

Simulation of the thermodynamics of folding and unfolding of the Trp-cage mini-protein TC5b using different combinations of force fields and solvation models

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Science China Chemistry 2010年第1期53卷 196-201页

作者： ZHANG john ZengHui State Key Laboratory of Precision Spectroscopy Department of PhysicsEast China Normal University Department of Chemistry New York UniversityNew YorkNew York 10003USA

Molecular dynamics simulations based on AMbER force fields(ff96 and ff03) and generalized born models(igb1 and igb5) have been carried out in order to study folding/unfolding of the Trp-cage mini-protein *** thermodynamic properties of TC5b were found to be sensitive to the specific version of the solvation model and force field *** the ff96/igb5 combination was used,the predicted melting temperature from unfolding simulations was in good agreement with the experimental value of 315 K,but the folding simulation did not *** most stable thermodynamic profile in both folding and unfolding simulations was obtained when the ff03/igb5 combination was employed,and the predicted melting temperature was about 345 K,showing over-stabilization of the *** using the igb1 version in combination with ff96 or ff03 were difficult to converge within the simulation time limit(50 ns).

关键词： Trp-cage TC5b folding and unfolding replica-exchange melting curve implicit solvation

bemisia tabaci Phylogenetic Groups in India and the Relative Transmission Efficacy of Tomato leaf curl bangalore virus by an Indigenous and an Exotic Population

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Journal of Integrative Agriculture 2012年第2期11卷 235-248页

作者： R V Chowda-Reddy M Kirankumar Susan E Seal V Muniyappa Girish b Valand M R Govindappa john Colvin Agriculture Health and Environment GroupNatural Resources InstituteUniversity of Greenwich at MedwayChatham MaritimeKentME4 4TBUnited Kingdom Southern Crop Protection and Food Research Centre London-N5V 4T3Canada Department of Plant Pathology University of Agricultural SciencesBangalore-560 065India Department of Plant Pathology Gujarat Agricultural UniversityAnand 388110GujaratIndia

bemisia tabaci adults from various host-plant species were collected from 31 regions across India.266 *** samples were first screened by RAPD-PCR to examine molecular variability and to select individuals with different ***-plant and region of collection were then used to select 25 individuals for PCR amplification and sequencing of their partial mitochondrial cytochrome oxidase subunit one（mtCOI）*** comparisons with mtCOI consensus sequences showed that the majority of these samples had 〈3.5% sequence divergence from groups currently termed Asia I,Asia II-5,Asia II-7,and Asia *** biotype-b *** from India clustered into the Middle East-Asia Minor 1 group.A new group of *** from Coimbatore,collected from pumpkin,was related most closely to the Asia I group（6.2% sequence divergence from the consensus Asia I sequence）.To increase our understanding of the epidemiology of tomato leaf curl disease（ToLCD）and the key *** genetic groups involved in virus spread,the indigenous Asia I and the exotic biotype-b population from South India were used to carry out transmission experiments using Tomato leaf curl bangalore virus（ToLCbV）.The acquisition access periods（AAP）,inoculation access periods（IAP）,latent periods（LP）,and ToLCbV transmission efficiencies of the two populations were compared and the biotype-b had the more efficient transmission *** results are discussed in relation to recent changes in the epidemiology of tomato leaf curl disease in South India.

关键词： begomoviruses mitochondrial cytochrome oxidase whitefly bemisia tabaci virus-vector relationships epidemiology

Guild composition and habitat use of voles in 2 forest landscapes in south-eastern Norway

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Integrative Zoology 2011年第4期6卷 299-310页

作者： Lucrezia GORINI john D.C.LINNELL Luigi bOITANI Ulrike HAUPTMANN Morten ODDEN Per WEGGE Erlend b.NILSEN Department of Animal and Human biology Sapienza University of RomeRomeItaly Faculty of Applied Ecology and Agricultural Sciences Hedmark University CollegeCampus EvenstadKoppangNorway Norwegian Institute for Nature Research TrondheimNorway Department of Ecology and Natural Resource Management Norwegian University of Life SciencesÅsNorway

It is widely believed that intensive forestry has influenced small mammal population dynamics,and thereby the entire mammalian community in Fennoscandian boreal *** nature of these impacts on the different species is subject to *** live-trapped voles between 2006 and 2009 in 2 commercially harvested forests in south-eastern *** investigated the variation in vole abundance among habitat types(*** forest and clear-cut)and the hypothesis that graminivorous species such as field voles(Microtus agrestis L.)benefit from clear-cuts at the expense of forest dwellers(*** bank vole,Myodes glareolus Schreb.),using fine-scale descriptors of the ground *** could not find support for the hypothesis that field voles show a preference for clear-cuts,and their overall abundance was low,while bank voles were the dominant species in all habitat types,including clear-cuts in the peak and pre-peak *** found a positive association between bank vole abundance and bilberry(Vaccinium myrtillus L.)availability rather than a specific habitat *** field vole density in clear-cuts might be due to variation in local productivity and ground vegetation as well as to large variation in the species temporal *** latter is particularly associated with the widespread decline of field voles in *** has the potential to negatively affect bank vole population dynamics because of the negative effect on bilberry development.

关键词： bank vole bilberry clear-cut field vole forestry

Cyclooxygenase-2 and epithelial growth factor receptor up-regulation during progression of barrett's esophagus to adenocarcinoma

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World Journal of Gastroenterology 2006年第6期12卷 928-934页

作者： Yan Li john M Wo Mukunda b Ray Whitney Jones Ruifeng R Su Susan Ellis Robert C G Martin Division of Surgical Oncology University of Louisville School ofMedicine Louisville KY 40202 United States Division of Gastroenterology/Hepatology University of Louisville School of MedicineLouisville KY 40202 United States Department of Anatomical Pathology University of Louisville School of Medicine Louisville KY40202 United States

AIM： To investigate the expression of cyclooxygenase-2 （COX-2） and epithelial growth factor receptor （EGFR） throughout the progression of barrett＇s esophagus （bE）. METHODS： COX-2 and EGFR protein expressions were detected by using immunohistochemical method. A detailed cytomorphological changes were determined. Areas of COX-2 and EGFR expression were quantified by using computer Imaging System. RESULTS： The expressions of both COX-2 and EGFR increased along with the progression from bE to esophagus adenocarcinoma （EAC）. A positive correlation was found between COX-2 expression and EGFR expression. CONCLUSION： COX-2 and EGFR may be cooperative in the stepwise progression from bE to EAC, thereby leading to carcinogenesis.

关键词： Cycloxygenase -2 (COX-2) Epithelial growth factor receptor (EGFR) barrett's esophagus Carcinogenesis

Two remarkable epimerizations imperative for the success of an asymmetric total synthesis of (+)-aigialospirol

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Science China Chemistry 2011年第1期54卷 31-42页

作者： FIGUEROA Ruth FELTENbERGER john b. GUEVARRA Christle C. HSUNG Richard P. Division of Pharmaceutical Sciences and Department of Chemistry University of Wisconsin School of Pharmaceutical Science and Technology Tianjin University

Two remarkable epimerization processes were uncovered during our pursuit of an enantioselective synthesis of(+)-aigialospirol featuring a cyclic acetal tethered ring-closing *** modeling,we were able to turn these two unexpected epimerizations to our advantage via modeling to ensure a successful and concise total synthesis,thereby firmly establishing cyclic acetal tethered RCM as a powerful strategy in natural product *** importantly,calculations allowed us to fully understand the nature and the mechanistic course of these two epimerizations that were imperative to the total synthesis efforts.

关键词： cyclic acetal tethered RCM (+)-aigialospirol anomeric effect and epimerization.