245 research outputs found
Power counting with one-pion exchange
Techniques developed for handing inverse-power-law potentials in atomic
physics are applied to the tensor one-pion exchange potential to determine the
regions in which it can be treated perturbatively. In S-, P- and D-waves the
critical values of the relative momentum are less than or of the order of 400
MeV. The RG is then used to determine the power counting for short-range
interaction in the presence of this potential. In the P-and D-waves, where
there are no low-energy bound or virtual states, these interactions have
half-integer RG eigenvalues and are substantially promoted relative to naive
expectations. These results are independent of whether the tensor force is
attractive or repulsive. In the 3S1 channel the leading term is relevant, but
it is demoted by half an order compared to the counting for the effective-range
expansion with only a short-range potential. The tensor force can be treated
perturbatively in those F-waves and above that do not couple to P- or D-waves.
The corresponding power counting is the usual one given by naive dimensional
analysis.Comment: 18 pages, RevTeX (further details, explanation added
Scattering from Singular Potentials in Quantum Mechanics
In non-relativistic quantum mechanics, singular potentials in problems with
spherical symmetry lead to a Schrodinger equation for stationary states with
non-Fuchsian singularities both as r tends to zero and as r tends to infinity.
In the sixties, an analytic approach was developed for the investigation of
scattering from such potentials, with emphasis on the polydromy of the wave
function in the r variable. The present paper extends those early results to an
arbitrary number of spatial dimensions. The Hill-type equation which leads, in
principle, to the evaluation of the polydromy parameter, is obtained from the
Hill equation for a two-dimensional problem by means of a simple change of
variables. The asymptotic forms of the wave function as r tends to zero and as
r tends to infinity are also derived. The Darboux technique of intertwining
operators is then applied to obtain an algorithm that makes it possible to
solve the Schrodinger equation with a singular potential containing many
negative powers of r, if the exact solution with even just one term is already
known.Comment: 19 pages, plain Tex. In this revised version, the analysis of Eq.
(5.29) has been amended, and an appendix has been added for completenes
Risk factors for liver decompensation and hcc in hcv-cirrhotic patients after daas: A multicenter prospective study
Background: Prospective studies on predictors of liver-related events in cirrhotic subjects achieving SVR after DAAs are lacking. Methods: We prospectively enrolled HCV cirrhotic patients in four Italian centers between November 2015 and October 2017. SVR and no-SVR cases were compared according to the presence or absence of liver-related events during a 24-month follow-up. Independent predictors of liver-related events were evaluated by Cox regression analysis. Results: A total of 706 subjects started DAAs therapy. SVR was confirmed in 687 (97.3%). A total of 61 subjects (8.9%) in the SVR group and 5 (26.3%) in the no-SVR group had liver-related events (p < 0.03). The incidence rate x 100 p/y was 1.6 for HCC, 1.7 for any liver decompensation, and 0.5 for hepatic death. Baseline liver stiffness (LSM) ≥ 20 kPa (HR 4.0; 95% CI 1.1–14.1) and genotype different from 1 (HR 7.5; 95% CI 2.1–27.3) were both independent predictors of liver decompensation. Baseline LSM > 20 KPa (HR 7.2; 95% CI 1.9–26.7) was the sole independent predictor of HCC. A decrease in liver stiffness (Delta LSM) by at least 20% at the end of follow-up was not associated with a decreased risk of liver-related events. Conclusion: Baseline LSM ≥ 20 kPa identifies HCV cirrhotic subjects at higher risk of liver-related events after SVR
Effect of immunosuppressive therapy on patients with inflammatory bowel diseases and hepatitis B or C virus infection.
Viral hepatitis reactivation has been widely reported in patients undergoing immunosuppressive therapy; however, few data are available about the risk of HBV and HCV reactivation in patients with inflammatory bowel disease, receiving immunosuppressive drugs. The aim of our study was to assess the prevalence of HBV and HCV infection in a consecutive series of patients with inflammatory bowel disease and to value the effects of immunosuppressive therapy during the course of the infection. Retrospective observational multicenter study included all consecutive patients with inflammatory bowel disease who have attended seven Italian tertiary referral hospitals in the last decade. A total of 5096 patients were consecutively included: 2485 Crohn's disease and 2611 Ulcerative Colitis. 30.5% and 29.7% of the patients were investigated for HBV and HCV infection. A total of 30 HBsAg positive, 17 isolated anti-HBc and 60 anti-HCV-positive patients were identified. In all, 20 patients with HBV or HCV infection received immunosuppressive therapy (six HBsAg+; four isolated anti-HBc+ and 10 anti-HCV+). One of six patients showed HBsAg+ and one of four isolated anti-HBc+ experienced reactivation of hepatitis. Two of six HBsAg patients received prophylactic therapy with lamivudine. Only one of 10 anti-HCV+ patients showed mild increase in viral load and ALT elevation. Screening procedures for HBV and HCV infection at diagnosis have been underused in patients with inflammatory bowel disease. We confirm the role of immunosuppressive therapy in HBV reactivation, but the impact on clinical course seems to be less relevant than previous reported
Perspectives on climate action and the changing burden of infectious diseases among young Italian doctors and students: a national survey
Background The eco-climatic crisis has been defined by the World Health Organization as the "single biggest health threat facing humanity," influencing both the emergence of zoonoses and the spread of vector-borne and water-borne diseases. The aim of this survey was to explore knowledge, eco-anxiety and attitudes toward the ecological and climate crisis among young Italian doctors and medical students.Methods A cross-sectional, multicenter survey was conducted from November 2022 to June 2023, by administering an anonymous questionnaire to Italian doctors and students of medicine. Endpoint of the study was a Knowledge, Attitudes and Practices (KAP) score on ecological and climate crisis (0-20 points). Association between variables and KAP score was assessed by Kruskal-Wallis' or Spearman's test, as appropriate, and significant variables were included into ordinal regression model and reported as adjusted odds ratio (aOR) with their 95% confidence intervals (CI).Results Both KAP and eco-anxiety scores showed acceptable levels of consistency with Cronbach's alpha. A total of 605 medical doctors and students living in 19 Italian regions were included in the study. Median age [Q1-Q3] was 27.6 [24.1-31.3] and females were 352 (58.2%). Despite showing good attitudes toward climate action, knowledge gap were found, with 42.5% (n = 257) of the respondents not knowing the temperature limits set by the Paris Agreements and 45.5% (n = 275) believing that climate change is caused by sunspots. Fears suggestive for eco-anxiety were common. At multivariable ordinal regression, high levels of eco-anxiety (aOR 1.29, p = 0.001) and low trust in government action (aOR 1.96, p = 0.003) were associated with a higher KAP score. Only one Italian medical school offered an educational module on climate change.Conclusion Young Italian doctors and medical students are concerned about the climate crisis but show poor knowledge of these topics. The Italian academic system should urgently respond to this need
Trends in prevalence of hepatitis B virus infection among Albanian blood donors, 1999-2009
<p>Abstract</p> <p>Background</p> <p>Hepatitis B virus (HBV) was among the first virus known to be transmitted by blood and blood productions. The objective of this study is to determine the trend of hepatitis B virus in blood donors.</p> <p>Materials and methods</p> <p>In this study 79274 blood donors were retrospectively evaluated for HBsAg. The donors were selected using personal questionnaire, physical examination and testing blood before donation. Blood banks records are used as source of information. The blood donors samples were analyzed for the presence of hepatitis B surface antigen (HBsAg) by commercial available kits ELISA method, third generation (from Abbott laboratory, Germany). A sample was considered as HBsAg positive when found twice repeatedly reactive. Reactive samples were not confirmed with addition tests.</p> <p>Results</p> <p>In the evaluation data, we found out that from 79274 of the total healthy blood donors, 15983 were voluntary donors, 52876 were family replacement donors and 10424 commercial blood donors. The prevalence of HBsAg in blood donors was 7.9%. It was increased steadily from 5.9% in 1999 to 9.1% in 2006 and decreased in 7.9% in 2009. According to blood donors status the HBsAg prevalence was 10.5% in commercial blood donors, 8.1% in voluntary donors and 8.6% in family replacement donors. The prevalence of anti-HBc in blood donors was 59.1%.</p> <p>Conclusion</p> <p>The prevalence of HBsAg was lower in voluntary non remunerate blood donors than commercial donors and family replacement blood donors. In FDs the prevalence was higher than VDs but lower than CDs. So, it is important to encourage the voluntary blood donors to become regularly blood donors.</p
The Medical Impact of Hepatitis D Virus Infection in Natives and Immigrants: The Italian Paradigm
Background and Aim: Ongoing migratory flows are reconstituting the hepatitis D virus (HDV) reservoir in Italy. We aimed to characterise the current clinical and virologic features of HDV infection in both native Italians and migrants. Methods: We enrolled 515 hepatitis B surface antigen (HBsAg)-positive patients with detectable anti-HDV antibodies from 32 Italian centres between August 2022 and July 2024; all patients underwent centralised virologic assessment. Results: Overall, 432 out of 515 (83.9%) patients were HDV-RNA-positive (4.39, 1.30–5.82 Log IU/mL; 99.0% HDV genotype-1). HDV-RNA levels correlated with ALT (rs = 0575, 0.514–0.630) and hepatitis B core-related antigen (rs = 0.521, 0.455–0.581). Native Italians (n = 317; 61.6%) were older than migrants (n = 198; 38.4%) (median age: 60, 55–65 vs. 46, 39–54 years; p < 0.001) and were more frequently male (68.1% vs. 49.5%; p < 0.001), with a higher prevalence of liver cirrhosis (70.3% vs. 50.5%; p < 0.001) and hepatocellular carcinoma (14.8% vs. 0.5%; p < 0.001). Among Italians, 223 (70.3%) had liver cirrhosis, 46 (14.5%) had chronic hepatitis D (CHD) without cirrhosis and 48 (15.1%) exhibited inactive/minimal disease with low viremia (≤ 3 Log IU/mL). Among migrants, 100 (50.5%) had liver cirrhosis, 58 (29.3%) had CHD and 40 (20.2%) showed inactive/minimal disease with low viremia (≤ 3 Log IU/mL). Conclusions: The current clinical landscape of chronic HDV infections in Italy is heterogeneous, changing the perspective of CHD as uniformly severe; although cirrhosis remains common, a substantial proportion of both native Italians and migrants present with milder forms of disease
Clinical associations and potential novel antigenic targets of autoantibodies directed against rods and rings in chronic hepatitis C infection
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