622 research outputs found

    Charge Asymmetry and Photon Energy Spectrum in the Decay Bsl+lγB_s \to l^+ l^- \gamma

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    We consider the structure-dependent amplitude of the decay Bsl+lγB_s \to l^+ l^- \gamma (l=e,μ)(l=e,\mu) in a model based on the effective Hamiltonian for bsˉl+lb \bar{s} \to l^+ l^- containing the Wilson coefficients C7,C9C_7,C_9 and C10C_{10}. The form factors characterising the matrix elements <γsˉγμ(1γ5)bBˉs>< \gamma | \bar{s} \gamma_\mu (1 \mp \gamma_5) b | \bar{B}_s> and <γsˉσμν(1γ5)bBˉs>< \gamma | \bar{s} \sigma_{\mu\nu} (1 \mp \gamma_5) b | \bar{B}_s> are taken to have the universal form fVfAfTfBsMBsRs/(3Eγ)f_V \approx f_A \approx f_T \approx f_{B_s} M_{B_s} R_s / (3 E_\gamma) suggested by recent work in QCD, where RsR_s is a parameter related to the light cone wave function of the BsB_s meson. Simple expressions are obtained for the charge asymmetry A(xγ)A(x_\gamma) and the photon energy spectrum dΓ/dxγ(xγ=2Eγ/MBs)d \Gamma/ d x_\gamma (x_\gamma = 2 E_\gamma/M_{B_s}). The decay rates are calculated in terms of the decay rate of BsγγB_s \to \gamma \gamma. The branching ratios are estimated to be Br(Bse+eγ)=2.0×108Br(B_s \to e^+ e^- \gamma) = 2.0 \times 10^{-8} and Br(Bsμ+μγ)=1.2×108Br(B_s \to \mu^+ \mu^- \gamma) = 1.2 \times 10^{-8}, somewhat higher than earlier estimates.Comment: sign of fTf_T corrected; new table and figure

    Hydrodynamic condition and suspended sediment diffusion in the Yellow Sea and East China Sea

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    Based on monthly averaged current, temperature, and salinity, we analyzed the changes of suspended sediment concentration (SSC) and the relationship with the warm current, coastal current, and cold water mass (CWM) in the East China Seas (ECSs). The result shows that the coastal current and surface diluted water are the route for transporting suspended sediment. The Kuroshio and its derived warm current branches play the important role of the continental shelf circulation system and control the diffusion of suspended sediment. High SSC has been mainly concentrated in coastal current and CWM. Two sedimentary dynamic patterns have been identified. The winter‐half‐year pattern lasts almost 7 months. The coastal currents off the Shandong Peninsula, northern Jiangsu, Zhejiang‐Fujian coast are the main routes for diffusion and deposition of the suspended sediment from the Yellow River and Changjiang River. The summer‐half‐year pattern is characterized by the well‐developed CWM. All CWMs have a unique function to trap suspended sediment under the thermocline due to weakening tidal current and residual current there. These CWMs in the Yellow Sea (YS) and north ECS are connected together. The layer above the thermocline is characterized by diluted water with low salinity, high temperature. Suspended sediment can be transported into the Okinawa Trough and the South Korea coast during this period. A strong eddy always occur nearby the Kuroshio bend at northeast Taiwan, which has promoted the exchange between the ECS shelf and Okinawa Trough, and the development of the shelf edge current and Taiwan warm current (TWC)

    Adefovir Dipivoxil for the Treatment of Hepatitis B e Antigen–Positive Chronic Hepatitis B

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    BACKGROUND In preclinical and phase 2 studies, adefovir dipivoxil demonstrated potent activity against hepatitis B virus (HBV), including lamivudine-resistant strains. METHODS We randomly assigned 515 patients with chronic hepatitis B who were positive for hepatitis B e antigen (HBeAg) to receive 10 mg of adefovir dipivoxil (172 patients), 30 mg of adefovir dipivoxil (173), or placebo (170) daily for 48 weeks. The primary end point was histologic improvement in the 10-mg group as compared with the placebo group. RESULTS After 48 weeks of treatment, significantly more patients who received 10 mg or 30 mg of adefovir dipivoxil per day than who received placebo had histologic improvement (53 percent [P CONCLUSIONS In patients with HBeAg-positive chronic hepatitis B, 48 weeks of 10 mg or 30 mg of adefovir dipivoxil per day resulted in histologic liver improvement, reduced serum HBV DNA and alanine aminotransferase levels, and increased the rates of HBeAg seroconversion. The 10-mg dose has a favorable risk–benefit profile for long-term treatment. No adefovir-associated resistance mutations were identified in the HBV DNA polymerase gene

    Temporal Changes in Extracellular Vesicle Hemostatic Protein Composition Predict Favourable Left Ventricular Remodeling after Acute Myocardial Infarction

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    The subset of plasma extracellular vesicles (EVs) that coprecipitate with low-density lipoprotein (LDL-EVs) carry coagulation and fibrinolysis pathway proteins as cargo. We investigated the association between LDL-EV hemostatic/fibrinolysis protein ratios and post-acute myocardial infarction (post-AMI) left ventricular (LV) remodeling which precedes heart failure. Protein concentrations of von Willebrand factor (VWF), SerpinC1 and plasminogen were determined in LDL-EVs extracted from plasma samples obtained at baseline (within 72 h post-AMI), 1 month and 6 months post-AMI from 198 patients. Patients were categorized as exhibiting adverse (n = 98) or reverse (n = 100) LV remodeling based on changes in LV end-systolic volume (increased or decreased ≥15) over a 6-month period. Multiple level longitudinal data analysis with structural equation (ML-SEM) model was used to assess predictive value for LV remodeling independent of baseline differences. At baseline, protein levels of VWF, SerpinC1 and plasminogen in LDL-EVs did not differ between patients with adverse versus reverse LV remodeling. At 1 month post-AMI, protein levels of VWF and SerpinC1 decreased whilst plasminogen increased in patients with adverse LV remodeling. In contrast, VWF and plasminogen decreased whilst SerpinC1 remained unchanged in patients with reverse LV remodeling. Overall, compared with patients with adverse LV remodeling, higher levels of SerpinC1 and VWF but lower levels of plasminogen resulted in higher ratios of VWF:Plasminogen and SerpinC1:Plasminogen at both 1 month and 6 months post-AMI in patients with reverse LV remodeling. More importantly, ratios VWF:Plasminogen (AUC = 0.674) and SerpinC1:Plasminogen (AUC = 0.712) displayed markedly better prognostic power than NT-proBNP (AUC = 0.384), troponin-I (AUC = 0.467) or troponin-T (AUC = 0.389) (p \u3c 0.001) to predict reverse LV remodeling post-AMI. Temporal changes in the ratios of coagulation to fibrinolysis pathway proteins in LDL-EVs outperform current standard plasma biomarkers in predicting post-AMI reverse LV remodeling. Our findings may provide clinical cues to uncover the cellular mechanisms underpinning post-AMI reverse LV remodeling

    Transcriptomes of Mouse Olfactory Epithelium Reveal Sexual Differences in Odorant Detection

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    To sense numerous odorants and chemicals, animals have evolved a large number of olfactory receptor genes (Olfrs) in their genome. In particular, the house mouse has ∼1,100 genes in the Olfr gene family. This makes the mouse a good model organism to study Olfr genes and olfaction-related genes. To date, whether male and female mice possess the same ability in detecting environmental odorants is still unknown. Using the next generation sequencing technology (paired-end mRNA-seq), we detected 1,088 expressed Olfr genes in both male and female olfactory epithelium. We found that not only Olfr genes but also odorant-binding protein (Obp) genes have evolved rapidly in the mouse lineage. Interestingly, Olfr genes tend to express at a higher level in males than in females, whereas the Obp genes clustered on the X chromosome show the opposite trend. These observations may imply a more efficient odorant-transporting system in females, whereas a more active Olfr gene expressing system in males. In addition, we detected the expression of two genes encoding major urinary proteins, which have been proposed to bind and transport pheromones or act as pheromones in mouse urine. This observation suggests a role of main olfactory system (MOS) in pheromone detection, contrary to the view that only accessory olfactory system (AOS) is involved in pheromone detection. This study suggests the sexual differences in detecting environmental odorants in MOS and demonstrates that mRNA-seq provides a powerful tool for detecting genes with low expression levels and with high sequence similarities

    Polymer strategies in perovskite solar cells

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    Since their emergence in 2013, perovskite solar cells have reached remarkable efficiencies exceeding 22%. Such rapid development of this technology has been possible, in part, due to the feed of ideas from previous research in organic photovoltaics (OPVs) and light emitting diodes (OLEDs). This comprehensive review discusses the various polymer strategies that have led to the success of perovskite devices: from hole and electron transporting materials to polymer templating agents. This review further covers how these strategies potentially serve to overcome the two major obstacles that stand in the way of global implementation of perovskite solar cells; stability and J-V curve hysteresis. Through reference and comparison of OPV, OLED, and perovskite technologies, we highlight the need for a unified approach to establish appropriate control systems and ageing protocols that are necessary to further research in this exciting direction. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017, 55, 549–568

    Security and privacy issues of physical objects in the IoT: Challenges and opportunities

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    In the Internet of Things (IoT), security and privacy issues of physical objects are crucial to the related applications. In order to clarify the complicated security and privacy issues, the life cycle of a physical object is divided into three stages of pre-working, in-working, and post-working. On this basis, a physical object-based security architecture for the IoT is put forward. According to the security architecture, security and privacy requirements and related protecting technologies for physical objects in different working stages are analyzed in detail. Considering the development of IoT technologies, potential security and privacy challenges that IoT objects may face in the pervasive computing environment are summarized. At the same time, possible directions for dealing with these challenges are also pointed out

    A diversity of uncharacterized reverse transcriptases in bacteria

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    Retroelements are usually considered to be eukaryotic elements because of the large number and variety in eukaryotic genomes. By comparison, reverse transcriptases (RTs) are rare in bacteria, with only three characterized classes: retrons, group II introns and diversity-generating retroelements (DGRs). Here, we present the results of a bioinformatic survey that aims to define the landscape of RTs across eubacterial, archaeal and phage genomes. We identify and categorize 1021 RTs, of which the majority are group II introns (73%). Surprisingly, a plethora of novel RTs are found that do not belong to characterized classes. The RTs have 11 domain architectures and are classified into 20 groupings based on sequence similarity, phylogenetic analyses and open reading frame domain structures. Interestingly, group II introns are the only bacterial RTs to exhibit clear evidence for independent mobility, while five other groups have putative functions in defense against phage infection or promotion of phage infection. These examples suggest that additional beneficial functions will be discovered among uncharacterized RTs. The study lays the groundwork for experimental characterization of these highly diverse sequences and has implications for the evolution of retroelements

    Primjena teorije sivih sustava na kvalitetu softverskih projekata

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    The aim of this work is the identification of software project quality performance measures that would enable valid comparison and ranking of the completed projects. Software projects can be characterized by a set of influence factors. A subset of the influence factors is relevant for software project quality. In order to predict and determine the ranking of software projects by their success, and thus present a valid software project quality performance measure, we employ Grey system theory. Grey relational analysis is a kind of method which enables determination of the relational degree of every factor in the system. The method can be used for systems that are incompletely described with relatively few data available, and for which standard statistical assumptions are not satisfied. Relational degree between seven relevant software project quality influence factors is calculated for a set of ten software projects. The results demonstrate the usefulness and applicability of the Grey system theory in software project quality assessment.Cilj rada je identifikacija mjera performanse kvalitete softverskog projekta koje bi omogućile usporedbu i rangiranje završenih projekata. Softverski projekti mogu se okarakterizirati skupom faktora utjecaja. Podskup tih faktora važan je za kvalitetu softverskih projekata. Da bi se predvidio i odredio poredak sofverskih projekata prema uspješnosti i na taj način predstavilo valjanu mjeru performanse kvalitete sofverskih projekata, koristi se teorija sivih sustava. Siva analiza odnosa je takva metoda koja omogućava određivanje stupnja odnosa svakog faktora u sustavu. Takva metoda koristi se za sustave koji su nepotpuno opisani s relativno malo podataka i za koje standardne statističke pretpostavke nisu zadovoljene. Stupanj odnosa između sedam bitnih faktora kvalitete softverskih projekata izračunat je na skupu od deset softverskih projekata. Rezultati pokazuju učinkovitost i primijenjivost teorije sivih sustava u ocjeni kvalitete softverskih projekata
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