144 research outputs found

    Hybrid approach to calculating proton stopping power in hydrogen

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    Proton stopping power in hydrogen is calculated using a hybrid method. A two-centre convergent close-coupling method is used for calculations involving the proton fraction of the beam, while the Born approximation is used for the hydrogen fraction. For proton-hydrogen collisions rearrangement processes are explicitly included via a two-centre expansion. Hydrogen-hydrogen collisions are calculated including one- and two-electron processes. Despite using the first-order approximation in the hydrogen-hydrogen channel, overall reasonably good agreement with experiment is seen above 100 keV. © Published under licence by IOP Publishing Ltd

    Close-coupling approach to antiproton-impact ionisation of H2 with analytical spherical averaging

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    Integrated cross section for single ionisation of molecular hydrogen by antiproton impact has been calculated in a wide range of impact energies from 1 keV up to 2 MeV using a close-coupling approach. For the first time all possible orientations of the molecular target have been accounted for using an ab initio analytical spherical averaging technique. Obtained results are in good agreement with experiment

    ASSESSMENT OF BIODIVERSITY OF CARABID BEETLES (COLEOPTERA, CARABIDAE) OF THE TSHETSHEN ISLAND IN THE СASPIAN SEA

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    Aim, material. Biodiversity of carabid beetles (Coleoptera, Carabidae) is studied for the Tshetshen Island in the Caspean Sea based on examination of 32799 adults belonging to 123 species collected during two seasons.Results. Five collecting sites on the Tshetshen Island were sampled and compared with data from the Nordovyi and Tiulenyi islands as well as from coastal areas of Dagestan. Carabid species composition of the Tshetshen Island differs in having a higher fraction of desert taxa. In this respect, it resembles more that of the Middle Asia and Kalmykia. Some species, common in the mainland, are not found on the island. Rank-abundance distributions, biodiversity indices and effective numbers of species were used to quantitify differences among collecting sites. In most cases, the data obtained fit the best to the Zipf-Mandelbrot distribution. Numbers of carabid species in sites ranged from 45 to 89. Despite of variation, the richness indices are shown to be significantly lower for the Tshetshen Island. This conclusion was confirmed using rarefaction curves. Decomposition of γ-diversity into its α- and β- components in terms of effective numbers of species has shown that α-diversity of carabids in mainland areas exceeds that of the Tshetshen Island only marginally while β-diversity is significantly higher. Cluster analysys of distance matrices has shown that the carabid assemblages of the Tshetshen Island are the most poor and specific, those from the coastal areas – the most species-rich while those of the Tiulenyi and Nordovyi islands are intermediate.Conclusion. Carabid assemblages of each island in the Caspian Sea may be considered as a rather randomly impoverished subset from the regional species pool of the Middle Asia and Caspian lowland

    Fully quantum-mechanical treatment of proton-hydrogen scattering

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    © Published under licence by IOP Publishing Ltd. A fully quantum-mechanical convergent close-coupling approach to proton collisions with atomic hydrogen has been developed. Cross sections for target ionisation and electron capture by the projectile have been calculated in the energy range from 20 keV to 1 MeV. Calculated electron capture cross sections are in good agreement with the experiment, however for ionisation discrepancies between theory and experiment at intermediate energies still remain

    Ionisation of noble gas atoms and H2O by antiproton impact

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    © Published under licence by IOP Publishing Ltd. A time-dependent convergent close-coupling approach to antiproton collisions with noble gas atoms and H2O has been developed using a fully multielectron treatment of the targets. Integrated cross sections for single ionisation have been calculated in a wide range of impact energies from 5 keV up to 2 MeV. Obtained results are in good agreement with experiment

    Calculation of antihydrogen formation via antiproton scattering with excited positronium

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    Detailed presentation of results shown in the ealrier Phys. Rev. Lett. (114, 183201, (2015)).Shows all partial cross sections for antihydrogen formation in collisions of antiprotons with positronium in quantum states n = 1-3

    Safety and on-treatment efficacy of telaprevir: the early access programme for patients with advanced hepatitis C

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    Background and aim Severe adverse events (AEs) compromise the outcome of direct antiviral agent-based treatment in patients with advanced liver fibrosis due to HCV infection. HEP3002 is an ongoing multinational programme to evaluate safety and efficacy of telaprevir (TVR) plus pegylated-interferon-alpha (PEG-IFN alpha) and ribavirin (RBV) in patients with advanced liver fibrosis caused by HCV genotype 1 (HCV-1).Methods 1782 patients with HCV-1 and bridging fibrosis or compensated cirrhosis were prospectively recruited from 16 countries worldwide, and treated with 12 weeks of TVR plus PEG-IFN/RBV, followed by 12 or 36 weeks of PEG-IFN and RBV (PR) alone dependent on virological response to treatment and previous response type.Results 1587 patients completed 12 weeks of triple therapy and 4 weeks of PR tail (53% cirrhosis, 22% HCV-1a). By week 12, HCV RNA was undetectable in 85% of naives, 88% of relapsers, 80% of partial responders and 72% of null responders. Overall, 931 patients (59%) developed grade 1-4 anaemia (grade 3/4 in 31%), 630 (40%) dose reduced RBV, 332 (21%) received erythropoietin and 157 (10%) were transfused. Age and female gender were the strongest predictors of anaemia. 64 patients (4%) developed a grade 3/4 rash. Discontinuation of TVR due to AEs was necessary in 193 patients (12%). Seven patients died (0.4%, six had cirrhosis).Conclusions in compensated patients with advanced fibrosis due to HCV-1, triple therapy with TVR led to satisfactory rates of safety, tolerability and on-treatment virological response with adequate managements of AEs.Janssen PharmaceuticsUniv Milan, Div Gastroenterol, Dept Med, Fdn IRCCS Ca Granda Osped Maggiore Policlin, Milan, ItalyHosp Univ 12 Octubre, Secc Aparato Digest, Madrid, SpainIM Sechenov First Moscow State Med Univ, EM Tareev Clin Nephrol Internal & Occupat Med, Moscow, RussiaUniversidade Federal de SĂŁo Paulo, Viral Hepatitis Div Infect Dis, Outpatient Clin HIV, SĂŁo Paulo, BrazilUniv Sydney, Royal Prince Alfred Hosp, AW Morrow Gastroenterol & Liver Ctr, Sydney, NSW 2006, AustraliaCharles Univ Prague, Fac Med 1, Dept Internal Med, Prague, Czech RepublicCent Mil Hosp Prague, Prague, Czech RepublicUniv Libre Brussels, Dept Gastroenterol Hepatopancreatol & Digest Onco, Erasme Univ Hosp, Liver Unit, Brussels, BelgiumCarol Davila Univ Med & Pharm, Natl Inst Infect Dis, Bucharest, RomaniaJanssen Pharmaceut, B-2340 Beerse, BelgiumJanssen Pharmaceut, Paris, FranceJanssen Res & Dev, Titusville, NJ USAJanssen Res & Dev, High Wycombe, Bucks, EnglandJanssen Cilag AG, Zug, SwitzerlandHannover Med Sch, D-30623 Hannover, GermanyUniversidade Federal de SĂŁo Paulo, Viral Hepatitis Div Infect Dis, Outpatient Clin HIV, SĂŁo Paulo, BrazilWeb of Scienc

    The David procedure after the Ross operation: case series

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    Pulmonary autograft in the aortic position provides high survival rate and quality of life for patients, low incidence of valve-related complications, and excellent hemodynamic characteristics both in the early and long-term period. However, in some patients in the long-term period, pulmonary autograft may dilate, which in turn is one of the reasons for reoperations. In patients who require surgery for annuloaortic ectasia with aortic valve (AV) regurgitation or aortic root aneurysm (or both) with normal AV leaflets, David procedure is considered.Aim. To analyze results of David procedure after a prior Ross operation.Material and methods. From April 2009 to December 2020, 212 Ross operations were performed on patients 18 years of age and older. The median age of the operated patients was 34 (27-45) years. In the long-term period, 10 (4,7%) patients required a second AV operation and 7 (3,3%) of them required another intervention on the ascending aorta due to aortic dilatation. Four out of 10 patients underwent David procedure. The follow-up period for patients after David procedure ranged from 2 to 84 months.Results. The age of patients ranged from 23 to 45 years. Three patients had hypertension. The follow-up period from Ross's operation to David's one was 26 to 140 months. All patients had enlarged aortic annulus from 27 to 30 mm. The duration of myocardial ischemia ranged from 87 to 142 minutes, while the duration of artificial circulation — from 119 to 165 minutes. The graft diameter was 30 mm in two patients and 32 mm in the remaining ones. The length of stay in intensive care unit ranged from 16 to 23 hours. In the early postoperative period, no one had following postoperative complications: acute renal failure requiring hemodialysis, perioperative myocardial injury, stroke, sternal infection, respiratory failure requiring mechanical ventilation for ≥24 hours, resternotomy for bleeding and tamponade. In addition, there were no in hospital deaths. All patients had no aortic regurgitation at the time of discharge. All patients are alive and there were no reoperations. In one patient, in the long-term period, there was a mild aortic regurgitation, while in three patients — there is no regurgitation.Conclusion. The presented case series show that David procedure can be performed safely and effectively in a significant number of patients requiring a second autograft surgery due to neosinus dilatation. In the medium term, the David procedure has shown good outcomes in these patients with 100% survival and no aortic regurgitation and reoperation

    Final results of the telaprevir access program: Fibroscan values predict safety and efficacy in hepatitis c patients with advanced fibrosis or cirrhosis

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    Background: Liver stiffness determined by transient elastography is correlated with hepatic fibrosis stage and has high accuracy for detecting severe fibrosis and cirrhosis in chronic hepatitis C patients. We evaluated the clinical value of baseline FibroScan values for the prediction of safety and efficacy of telaprevir-based therapy in patients with advanced fibrosis and cirrhosis in the telaprevir Early Access Program HEP3002. Methods: 1,772 patients with HCV-1 and bridging fibrosis or cirrhosis were treated with telaprevir plus pegylated interferon-α and ribavirin (PR) for 12 weeks followed by PR alone, the total treatment duration depending on virological response and previous response type. Liver fibrosis stage was determined either by liver biopsy or by non-invasive markers. 1,282 patients (72%) had disease stage assessed by FibroScan; among those 46% were classified as Metavir F3 at baseline and 54% as F4. Results: Overall, 1,139 patients (64%) achieved a sustained virological response (SVR) by intentionto- treat analysis. Baseline FibroScan values were tested for association with SVR and the occurrence of adverse events. By univariate analysis, higher baseline FibroScan values were predictive of lower sustained virological response rates and treatment-related anemia. By multivariate analysis, FibroScan was no longer statistically significant as an independent predictor, but higher FibroScan values were correlated with the occurrence of infections and serious adverse events. Conclusions: FibroScan has a limited utility as a predictor of safety and efficacy in patients treated with telaprevir-based triple therapy. Nevertheless it can be used in association with other clinical and biological parameters to help determine patients who will benefit from the triple regiments. © 2015 Lepida et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

    The Hilbert-Schmidt Theorem Formulation of the R-Matrix Theory

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    Using the Hilbert-Schmidt theorem, we reformulate the R-matrix theory in terms of a uniformly and absolutely convergent expansion. Term by term differentiation is possible with this expansion in the neighborhood of the surface. Methods for improving the convergence are discussed when the R-function series is truncated for practical applications.Comment: 16 pages, Late
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