N′-(2-Fluoro­benzyl­idene)acetohydrazide

The title compound, C9H9FN2O, was prepared by the reaction between 2-fluoro­benzophenone and acetohydrazide. In the crystal structure, inversion dimers linked by pairs of N—H⋯O hydrogen bonds occur, generating R 2 2(8) loops

Lamivudine plus adefovir is a good option for chronic hepatitis B patients with viral relapse after cessation of lamivudine treatment

<p>Abstract</p> <p>Aim</p> <p>Currently, there is no consensus on the retreatment recommendation of chronic hepatitis B (CHB) patients with viral rebound after cessation of treatment. In the search of reasonable treatment, we compared the efficacy and safety of adefovir (ADV) plus lamivudine (LAM) and LAM alone for the retreatment of patients with viral relapse but without genotypic resistance after cessation of LAM.</p> <p>Methods</p> <p>This is a prospective controlled study, and a total of 53 hepatitis B e antigen (HBeAg)-positive patients with viral rebound but without resistance were received either LAM plus ADV or LAM alone treatment.</p> <p>Results</p> <p>After 1-year treatment, more patients who received LAM plus ADV than those who received LAM alone had ALT normalization (84% versus 53.6%, P = 0.018) or HBV DNA levels below 1000 copies/mL (80% versus 42.9%, P < 0.006). Seven patients receiving LAM plus ADV had HBeAg seroconversion, as compared with 0 in patients receiving ALM alone (28% versus 0%, P = 0.003). During 1-year retreatment, five patients receiving LAM alone had virological breakthrough and all of them had LAM resistance strains (rtM204V/I), while no LAM- or ADV- associated resistance strains were detected in patients receiving LAM plus ADV. All patients receiving LAM plus ADV were well tolerated, and no serious side effects were noted.</p> <p>Conclusions</p> <p>Patients treated with LAM plus ADV exhibited significantly greater virological, biochemical and serological responses compared with LAM alone. These data suggested that combination of LAM plus ADV would be a good option for the retreatment of CHB patients with viral relapse after cessation of LAM.</p

Antibody dependent enhancement infection of Enterovirus 71 in vitro and in vivo

BACKGROUND: Human enterovirus 71 (EV71) has emerged as a significant cause of acute encephalitis and deaths in young children. The clinical manifestations caused by EV71 varied from mild hand, foot and mouth disease to severe neurological complications and deaths, but its pathogenesis remains elusive. Antibody dependent enhancement (ADE) infection has been reported in various viruses and has been shown to contribute to disease severity. RESULTS: In this study, the presence of sub-neutralizing antibody was demonstrated to enhance EV71 infection in THP-1 cells and increase the mortality of EV71 infection in a suckling mouse model. Further, a secondary infection model was established to characterize the correlation between ADE and disease severity, and primary asymptomatic EV71 infection was shown to increase the mortality of the secondary EV71 infection in suckling mice. CONCLUSIONS: Together, these in vitro and in vivo experiments strongly supported the hypothesis of ADE infection of EV71. The present findings indicate ADE might contribute to the pathogenesis of severe EV71 infection, and raise practical issues of vaccine development and antibody-based therapy

Modelling the dynamical friction timescale of sinking satellite

When a satellite galaxy falls into a massive dark matter halo, it suffers the dynamical friction force which drag it into the halo center and finally it merger with the central galaxy. The time interval between entry and merger is called as the dynamical friction timescale (T_df). Many studies have been dedicated to derive T_df using analytical models or N-body simulations. These studies have obtained qualitative agreements on how T_df depends on the orbit parameters, and mass ratio between satellite and host halo. However, there are still disagreements on the accurate form of T_df . In this paper, we present a semi-analytical model to predict T_df and we focus on interpreting the discrepancies among different studies. We find that the treatment of mass loss from satellite by tidal stripping dominates the behavior of T_df . We also identify other model parameters which affect the predicted T_df.Comment: 13 pages, 7 figures, accepted for publication in Research in Astronomy and Astrophysics (RAA

Double exchange model on triangular lattice: non-coplanar spin configuration and phase transition near quarter filling

Unconventional anomalous Hall effect in frustrated pyrochlore oxides is originated from spin chirality of non-coplanar localized spins, which can also be induced by the competition between ferromagnetic (FM) double exchange interaction $J_{H}$ and antiferromagnetic superexchange interaction $J_{AF}$. Here truncated polynomial expansion method and Monte Carlo simulation are adopted to investigate the above model on two-dimensional triangular lattice. We discuss the influence of the range of FM-type spin-spin correlation and strong electron-spin correlation on the truncation error of spin-spin correlation near quarter filling. Two peaks of the probability distribution of spin-spin correlation in non-coplanar spin configuration clearly show that non-coplanar spin configuration is an intermediate phase between FM and 120-degree spin phase. Near quarter filling, there is a phase transition from FM into non-coplanar and further into 120-degree spin phase when $J_{AF}$ continually increases. Finally the effect of temperature on magnetic structure is discussed.Comment: 10 pages, 5 figure

Arbuscular Mycorrhiza Improves Leaf Food Quality of Tea Plants

Tea (Camellia sinensis) plants inhabit arbuscular mycorrhizal fungi (AMF) in rhizosphere, whereas it is not clear whether AMF improves leaf food quality of tea plants. A potted study was conducted to determine effects of Claroideoglomus etunicatum, Diversispora spurca, D. versiformis and a mixture of the three AMF species on leaf sugar, amino acid, soluble protein, tea polyphenol, catechuic acid, and flavonoid contents of Camellia sinensis ‘Fuding Dabaicha’ seedlings. After 12 weeks of AMF inoculation, mycorrhizal plants recorded significantly higher shoot biomass and total leaf area, whilst the effect was ranked as C. etunicatum &gt; D. spurca &gt; mixed-AMF &gt; D. versiformis in the decreasing order. AMF treatments significantly increased leaf total amino acid concentrations, accompanied with up-regulation of amino acid synthetic enzymes genes glutamine synthetase (CsGS), glutamate synthase (CsGOGAT) and glutamate dehydrogenase (CsGDH). Leaf glucose, sucrose, total soluble protein, tea polyphenol, catechuic acid, and flavonoid contents were significantly higher in AMF- than in non-AMF-inoculated plants. In addition, mycorrhizal inoculation notably up-regulated the expression level of leaf 3-hydroxy-3-methylglutaryl coenzyme gene (CsHMGR), ascorbate peroxidase gene (CsAPX), and tea caffeine synthase 1 gene (CsTCS1). These results implied that AMF inoculation had positive effects on leaf food quality partly by means of up-regulation of relevant gene expression in ‘Fuding Dabaicha’ seedlings

Old stellar population synthesis: New age and mass estimates for Mayall II = G1

Mayall II = G1 is one of the most luminous globular clusters (GCs) in M31. Here, we determine its age and mass by comparing multicolor photometry with theoretical stellar population synthesis models. Based on far- and near-ultraviolet GALEX photometry, broad-band UBVRI, and infrared JHK_s 2MASS data, we construct the most extensive spectral energy distribution of G1 to date, spanning the wavelength range from 1538 to 20,000 A. A quantitative comparison with a variety of simple stellar population (SSP) models yields a mean age that is consistent with G1 being among the oldest building blocks of M31 and having formed within ~1.7 Gyr after the Big Bang. Irrespective of the SSP model or stellar initial mass function adopted, the resulting mass estimates (of order $10^7 M_\odot$) indicate that G1 is one of the most massive GCs in the Local Group. However, we speculate that the cluster's exceptionally high mass suggests that it may not be a genuine GC. We also derive that G1 may contain, on average, $(1.65\pm0.63)\times10^2 L_\odot$ far-ultraviolet-bright, hot, extreme horizontal-branch stars, depending on the SSP model adopted. On a generic level, we demonstrate that extensive multi-passband photometry coupled with SSP analysis enables one to obtain age estimates for old SSPs to a similar accuracy as from integrated spectroscopy or resolved stellar photometry, provided that some of the free parameters can be constrained independently.Comment: Accepted for Publication in RAA, 12 pages, 1 figure, 2 table