630 research outputs found

    An embedding technique for the solution of reaction-fiffusion equations on algebraic surfaces with isolated singularities

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    In this paper we construct a parametrization-free embedding technique for numerically evolving reaction-diffusion PDEs defined on algebraic curves that possess an isolated singularity. In our approach, we first desingularize the curve by appealing to techniques from algebraic geometry.\ud We create a family of smooth curves in higher dimensional space that correspond to the original curve by projection. Following this, we pose the analogous reaction-diffusion PDE on each member of this family and show that the solutions (their projection onto the original domain) approximate the solution of the original problem. Finally, we compute these approximants numerically by applying the Closest Point Method which is an embedding technique for solving PDEs on smooth surfaces of arbitrary dimension or codimension, and is thus suitable for our situation. In addition, we discuss the potential to generalize the techniques presented for higher-dimensional surfaces with multiple singularities

    HCV reinfection incidence and spontaneous clearance rates in HIV-positive men who have sex with men in Western Europe

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    BACKGROUND & AIMS: Moderate cure rates of acute hepatitis C virus (HCV) infections with pegylated interferon and ribavirin have been described in the last decade in men who have sex with men (MSM), who are also coinfected with the human immunodeficiency virus (HIV). However, a subsequent high incidence of HCV reinfections has been reported regionally in men who both clear the infection spontaneously or who respond to treatment. METHODS: Retrospective analysis of reinfections in HIV infected MSM in eight centers from Austria, France, Germany, and the UK within the NEAT network between May 2002 and June 2014. RESULTS: Of 606 individuals who cleared HCV spontaneously or were successfully treated, 149 (24.6%) presented with a subsequent HCV reinfection. Thirty out of 70 (43%) who cleared again or were successfully treated, presented with a second reinfection, 5 with a third, and one with a fourth reinfection. The reinfection incidence was 7.3/100 person-years (95% CI 6.2-8.6). We found a trend for lower incidence among individuals who had spontaneously cleared their incident infection than among individuals who were treated (Hazard ratio 0.62, 95% CI 0.38-1.02, p=0.06). Spontaneous clearance of reinfection was associated with ALT levels >1000IU/ml and spontaneous clearance of a prior infection. CONCLUSIONS: HCV reinfection is an issue of major concern in HIV-positive MSM. Prevention strategies are needed for high risk groups to reduce morbidity and treatment costs. HIV-positive MSM with a prior HCV infection should be tested every 3 to 6months for reinfection. Those who had achieved a reinfection should be tested every 3months. LAY SUMMARY: We evaluated the occurrence of HCV reinfection in HIV-positive men who have sex with men. We found an alarming incidence of 7.3/100 person-years. Prevention measures need to address this specific subgroup of patients at high risk for HCV

    Systematic review and meta-analysis of hepatitis C virus infection and HIV viral load: New insights into epidemiologic synergy

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    INTRODUCTION: Hepatitis C virus (HCV) and HIV infection frequently co-occur due to shared transmission routes. Co-infection is associated with higher HCV viral load (VL), but less is known about the effect of HCV infection on HIV VL and risk of onward transmission. METHODS: We undertook a systematic review comparing 1) HIV VL among ART-naïve, HCV co-infected individuals versus HIV mono-infected individuals and 2) HIV VL among treated versus untreated HCV co-infected individuals. We performed a random-effects meta-analysis and quantified heterogeneity using the I2 statistic. We followed Cochrane Collaboration guidelines in conducting our review and PRISMA guidelines in reporting results. RESULTS AND DISCUSSION: We screened 3925 articles and identified 17 relevant publications. A meta-analysis found no evidence of increased HIV VL associated with HCV co-infection or between HIV VL and HCV treatment with pegylated interferon-alpha-2a/b and ribavirin. CONCLUSIONS: This finding is in contrast to the substantial increases in HIV VL observed with several other systemic infections. It presents opportunities to elucidate the biological pathways that underpin epidemiological synergy in HIV co-infections and may enable prediction of which co-infections are most important to epidemic control

    Полифункциональность языковой единицы в формате двуязычного контекста

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    Предложенный материал показывает взаимосвязь функций языка на примере наименований предприятий конкретного профиля деятельности - кафе и ресторанов Томска. Показана их взаимосвязь, как основа полифункциональности языковой единицы. Интерпретированные языковые средства, которые использованы в названиях в формате двуязычного контекста

    Safety and Efficacy of Ombitasvir, Paritaprevir With Ritonavir ± Dasabuvir With or Without Ribavirin in Patients With Human Immunodeficiency Virus-1 and Hepatitis C Virus Genotype 1 or Genotype 4 Coinfection: TURQUOISE-I Part 2.

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    BACKGROUND: Ombitasvir, paritaprevir with ritonavir, and dasabuvir (OBV/PTV/r ± DSV) ±ribavirin (RBV) are approved to treat hepatitis C virus (HCV) genotype 1 and 4 infection. Here, we investigate the safety and efficacy of OBV/PTV/r + DSV ±RBV for HCV genotype 1, and OBV/PTV/r + RBV for HCV genotype 4, in human immunodeficiency virus (HIV)-1 coinfected patients with or without compensated cirrhosis. METHODS: TURQUOISE-I, Part 2 is a phase 3 multicenter study. Patients with or without cirrhosis were HCV treatment-naive or -experienced, on an HIV-1 antiretroviral regimen containing atazanavir, raltegravir, dolutegravir, or darunavir (for genotype 4 only), and had plasma HIV-1 ribonucleic acid <40 copies/mL at screening. Patients received OBV/PTV/r ± DSV ±RBV for 12 or 24 weeks. RESULTS: In total, 228 patients were treated according to guidelines. Sustained virologic response at posttreatment week 12 (SVR12) was achieved by 194 of 200 (97%) and 27 of 28 (96%) patients with HCV genotype 1 and genotype 4 infection, respectively. There were 2 virologic failures: 1 breakthrough and 1 relapse in a cirrhotic and a noncirrhotic patient with genotype 1b and 1a infection, respectively. One reinfection occurred at posttreatment week 12 in a genotype 1a-infected patient. Excluding nonvirologic failures, the SVR12 rates were 98% (genotype 1) and 100% (genotype 4). Adverse events were mostly mild in severity and did not lead to discontinuation. Laboratory abnormalities were rare. CONCLUSIONS: The OBV/PTV/r ±DSV was well tolerated and yielded high SVR12 rates in patients with HCV genotype 1 or genotype 4/HIV-1 coinfection. The OBV/PTV/r ± DSV ±RBV is a potent HCV treatment option for patients with HIV-1 coinfection, regardless of treatment experience

    Hepatitis C virus (HCV) RNA profiles among chronic HIV/HCV-coinfected individuals in ESPRIT; spontaneous HCV RNA clearance observed in nine individuals.

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    OBJECTIVES: Studies have shown that hepatitis C virus (HCV) RNA levels remain stable over time in HIV/HCV-coinfected individuals taking combination antiretroviral therapy (cART), while spontaneous clearance of HCV RNA during the persistent infection phase has been documented only rarely among those with the CC interleukin (IL)-28B genotype. This study describes HCV RNA profiles and factors associated with changes over time in HCV RNA levels in the ESPRIT study. METHODS: HIV/HCV-coinfected individuals positive for HCV RNA were included in the study. Follow-up was counted from the first HCV RNA positive test and censored at the initiation of interferon-based treatment. HCV RNA and IL-28B measurements were performed in the same reference laboratory. Random effects mixed models were used to analyse changes over time in HCV RNA. RESULTS: A total of 312 ESPRIT patients were included in the study (151 in the arm receiving subcutaneous recombinant IL-2 and 161 in the control arm). Most of the patients were white (89%) and male (76%), and they had a median of 5 HCV RNA measurements per person [interquartile range (IQR) 3-6; range 1-9]. Median follow-up was 5 years (IQR: 2-6 years). At baseline, 96% of patients were taking cART and 93% had undetectable HIV RNA. Mean HCV RNA levels decreased by 13% per year over the study period [95% confidence interval (CI) 8-18%; P < 0.0001]. Baseline HCV RNA levels and the change over time in HCV RNA did not differ by randomization arm (P = 0.16 and P = 0.56, respectively). Nine individuals spontaneously cleared HCV RNA during follow-up [IL-28B genotypes: CC, five patients (56%); CT, four patients (44%)]. CONCLUSIONS: HCV RNA levels decreased over time in this population with well-controlled HIV infection. Spontaneous clearance of HCV RNA was documented in five individuals with IL-28B genotype CC and four with the CT genotype
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