360 research outputs found

    QCD Sum Rule Analysis of the Decays B→Kℓ+ℓ−B \to K \ell^+ \ell^- and B→K∗ℓ+ℓ−B \to K^* \ell^+ \ell^-

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    We use QCD sum rules to calculate the hadronic matrix elements governing the rare decays B→Kℓ+ℓ−B \to K \ell^+ \ell^- and B→K∗ℓ+ℓ−B \to K^* \ell^+ \ell^- induced by the flavour changing neutral current b→sb \to s transition. We also study relations among semileptonic and rare B→K(∗)B \to K^{(*)} decay form factors. The analysis of the invariant mass distribution of the lepton pair in B→K(∗)ℓ+ℓ−B \to K^{(*)} \ell^+ \ell^- and of the angular asymmetry in B→K∗ℓ+ℓ−B \to K^* \ell^+ \ell^- provides us with interesting tests of the Standard Model and its extensions.Comment: 26 pages REVTEX + 7 figures. Some typos corrected, figure 5 and 7 modified. This version will appear on Physical Review

    Can the Mechanism for π1→ηπ,η′π\pi_1\to \eta\pi,\eta'\pi Hybrid Decays be Detected?

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    Two mechanisms for the π1\pi_1 (JPC=1−+J^{PC}=1^{-+}) hybrid meson decay processes π1→ηπ,η′π\pi_1\to\eta\pi,\eta'\pi are investigated. These mechanisms are applied to ϕ→ηγ,η′γ\phi\to\eta\gamma,\eta'\gamma and J/ψ→ηγ,η′γJ/\psi\to\eta\gamma,\eta'\gamma decays to illustrate the validity of the decay mechanisms and to obtain independent information on the coupling of η,η′\eta,\eta' to quark and gluonic operators. From this information, we find that Γ(π1→ηπ)/Γ(π1→η′π)\Gamma(\pi_1\to\eta\pi)/\Gamma(\pi_1\to\eta'\pi) is substantially different in the two decay mechanisms, and hence future experimental measurements of this ratio will provide valuable information for substantiating the hybrid nature of these states and for determining the mechanism for these hybrid decays.Comment: 5 pages, revtex, 1 eps figure embedded in manuscript. Analysis and references extended in v

    Biochemical and molecular studies of 132 patients with galactosemia

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    We evaluated 132 galactosemia patients for the Q188R (glutamine-188 to arginine) mutation in the human galactose-1-phosphate uridyltransferase (GALT) gene and for GALT activity in their hemolysates by a sensitive radioisotopic method. In those without any detectable GALT activity (GG), the Q188R mutation constituted 67% of the alleles. In patients with detectable GALT activity (GV), only 16% of the alleles were accounted for by Q188R. In all patients who were homozygous for the Q188R mutation, no erythrocyte GALT activity could be demonstrated. There was an extensive variation in the amount of detectable GALT activity ranging from 0.1% to 5% of the normal values among the GV patients. There was a difference in the frequency of Q188R mutation in the GALT alleles among patients belonging to different racial and ethnic groups. In Caucasian and Hispanic patients, the frequency was not far different (64% and 58%, respectively). On the other hand, only 12% of the GALT alleles with Q188R were found in African-American patients.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47637/1/439_2004_Article_BF00201593.pd

    Intimate partner violence and oral HIV pre-exposure prophylaxis adherence among young African women

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    Objective: To estimate the effect of intimate partner violence (IPV) on oral pre-exposure prophylaxis (PrEP) adherence among adolescent girls and young women (AGYW). Design: We conducted a secondary analysis of data from HIV Prevention Trials Network 082 (HPTN 082), a multisite prospective study designed to assess oral PrEP adherence among AGYW in southern Africa. Methods: We estimated the relative prevalence of high PrEP adherence 3 and 6 months after initiation among AGYW 16 – 25 years who reported a history of any IPV in the past year at enrollment versus AGYW who did not, both overall and by age. High adherence was defined as an intracellular tenofovir-diphosphate concentration at least 700 fmol/ punch or more dried blood spots. Results: Among 409 PrEP-initiating AGYW, half (49%) reported experiencing any IPV by a current/recent partner in the year prior to enrollment. Overall, a similar proportion of AGYW who reported IPV had high PrEP adherence at months 3 and 6 as AGYW who did not report IPV. There was, however, evidence of effect modification by age at month 3: among AGYW less than 21 years old, those who reported IPV were less than half as likely to have high adherence [adjusted PR (aPR) = 0.43, 95% confidence interval (CI) 0.22– 0.86]; among AGYW aged 21 years or older, those who reported IPV were more than twice as likely to have high adherence (aPR = 2.21, 95% CI 1.34– 3.66). At month 6, effect estimates within each age stratum were consistent in direction to those at month 3. Conclusion: IPV events may either impede or motivate PrEP adherence among African AGYW, with age appearing to be an important consideration for IPV-related adherence interventions

    Demographics of sources of HIV-1 transmission in Zambia: a molecular epidemiology analysis in the HPTN 071 PopART study

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    BACKGROUND: In the last decade, universally available antiretroviral therapy (ART) has led to greatly improved health and survival of people living with HIV in sub-Saharan Africa, but new infections continue to appear. The design of effective prevention strategies requires the demographic characterisation of individuals acting as sources of infection, which is the aim of this study. METHODS: Between 2014 and 2018, the HPTN 071 PopART study was conducted to quantify the public health benefits of ART. Viral samples from 7124 study participants in Zambia were deep-sequenced as part of HPTN 071-02 PopART Phylogenetics, an ancillary study. We used these sequences to identify likely transmission pairs. After demographic weighting of the recipients in these pairs to match the overall HIV-positive population, we analysed the demographic characteristics of the sources to better understand transmission in the general population. FINDINGS: We identified a total of 300 likely transmission pairs. 178 (59·4%) were male to female, with 130 (95% CI 110-150; 43·3%) from males aged 25-40 years. Overall, men transmitted 2·09-fold (2·06-2·29) more infections per capita than women, a ratio peaking at 5·87 (2·78-15·8) in the 35-39 years source age group. 40 (26-57; 13·2%) transmissions linked individuals from different communities in the trial. Of 288 sources with recorded information on drug resistance mutations, 52 (38-69; 18·1%) carried viruses resistant to first-line ART. INTERPRETATION: HIV-1 transmission in the HPTN 071 study communities comes from a wide range of age and sex groups, and there is no outsized contribution to new infections from importation or drug resistance mutations. Men aged 25-39 years, underserved by current treatment and prevention services, should be prioritised for HIV testing and ART. FUNDING: National Institute of Allergy and Infectious Diseases, US President's Emergency Plan for AIDS Relief, International Initiative for Impact Evaluation, Bill & Melinda Gates Foundation, National Institute on Drug Abuse, and National Institute of Mental Health
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