704 research outputs found

    Hadronic Equipartition of Quark and Glue Momenta

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    If the ``glue'' which binds quarks within hadrons takes the form of strings, then a virial theorem may be derived which shows how the total hadron four momentum splits up into a quark contribution plus a glue contribution. The hadrons made up of light quarks exhibit an equipartion of four momentum into equal parts quarks and glue. The agreement with the experimental ``parton'' distribution four momentum sum rule is quite satisfactory as is the string fragmentation model.Comment: four pages, RevTeX format, one figure *.ep

    Analysis of patients' needs after liver transplantation in Tuscany: a prevalence study.

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    BACKGROUND: The reorganization of the healthcare system in Tuscany aims at characterizing the hospitals as a place for the treatment of acute patients. This event, together with the improvement of long-term survival after orthotopic liver transplantation (OLT), calls for a management network able to ensure effective continuity of care for patient needs in the posttransplantation period. MATERIALS AND METHODS: An observational study of prevalence has been carried out with the primary objective to evaluate patients' needs and criticalities both in routine daily life and in urgency in the posttransplantation period and the capacity of the regional health system to support them. A survey, using a semi-structured questionnaire consisting of 27 questions, was administered to all patients resident in Tuscany who underwent transplantation from 2000 to 2010. The survey tool assessed the following: socio-demographic data, personal, family and social difficulties, problems emerged in the clinical routine and urgency, resolution modality, relationships with the general practitioner and the referral specialist, and services the patients would appreciate receiving in their province of residence. RESULTS: In the study, 346 patients matched the inclusion criteria of the study, 324 gave telephone consent to participate in the survey, and 225 responded (69.4%). The most frequent difficulties were as follows: depression (39.5%), difficulty in returning to work (29.3%), low income (22.6%), lack of self-sufficiency (22.6%), addictions (19.1%) (cigarette smoking 16.4%), 12.4% eating disorders, and 18.9% other difficulties (social isolation, absence of a family network, and so on). The main reasons for dissatisfaction were as follows: difficulty to obtain the required laboratory tests and lack of a reference structure at the local health facility. Few patients have a referral specialists in their area and most of them primarily refer to the Transplant Center even late after the procedure. DISCUSSION: Early diagnosis of specific conditions (depression, addiction, and eating disorders) should be implemented in the follow-up period and services such as counselling, dietary support, rehabilitation, and social services should be provided locally. An integrated management system between the transplantation center and the local facilities (hospitals, general practitioners, primary care, and laboratories) should be implemented and referral specialized centers should be identified locally

    Role of the exchange and correlation potential into calculating the x-ray absorption spectra of half-metallic alloys: the case of Mn and Cu K-edge XANES in Cu2_2MnM (M = Al, Sn, In) Heusler alloys

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    This work reports a theoretical study of the x-ray absorption near-edge structure spectra at both the Cu and the Mn K-edge in several Cu2_2MnM (M= Al, Sn and In) Heusler alloys. Our results show that {\it ab-initio} single-channel multiple-scattering calculations are able of reproducing the experimental spectra. Moreover, an extensive discussion is presented concerning the role of the final state potential needed to reproduce the experimental data of these half-metallic alloys. In particular, the effects of the cluster-size and of the exchange and correlation potential needed in reproducing all the experimental XANES features are discussed.Comment: 15 pages, 5 figure

    Perfusion machines and hepatocellular carcinoma: a good match between a marginal organ and an advanced disease?

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    Abstract Hepatocellular carcinoma (HCC) accounts for 90% of primary liver cancers, is the second leading cause of cancer-related deaths and the leading cause of death in patients with cirrhosis. Liver transplantation (LT) represents the ideal treatment for selected patients as it removes both the tumor and the underlying cirrhotic liver with 5-year survival rates higher than 70%. Unfortunately, due to tumor characteristics, patient co-morbidities or shortage of organs available for transplant, only 20% of patients can undergo curative treatment. Ex situ machine perfusion (MP) is a technology recently introduced that might potentially improve organ preservation, allow graft assessment and increase the pool of available organs. The purpose of this review is to provide an update on the current role of ex situ liver MP in liver transplantation for HCC patients

    Transcriptome analysis of differentiating spermatogonia stimulated with kit ligand

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    Kit ligand (KL) is a survival factor and a mitogenic stimulus for differentiating spermatogonia. However, it is not known whether KL also plays a role in the differentiative events that lead to meiotic entry of these cells. We performed a wide genome analysis of difference in gene expression induced by treatment with KL of spermatogonia from 7-day-old mice, using gene chips spanning the whole mouse genome. The analysis revealed that the pattern of RNA expression induced by KL is compatible with the qualitative changes of the cell cycle that occur during the subsequent cell divisions in type A and B spermatogonia, i.e. the progressive lengthening of the S phase and the shortening of the G2/M transition. Moreover, KL up-regulates in differentiating spermatogonia the expression of early meiotic genes (for instance: Lhx8, Nek1, Rnf141, Xrcc3, Tpo1, Tbca, Xrcc2, Mesp1, Phf7, Rtel1), whereas it down-regulates typical spermatogonial markers (for instance: Pole, Ptgs2, Zfpm2, Egr2, Egr3, Gsk3b, Hnrpa1, Fst, Ptch2). Since KL modifies the expression of several genes known to be up-regulated or down-regulated in spermatogonia during the transition from the mitotic to the meiotic cell cycle, these results are consistent with a role of the KL/kit interaction in the induction of their meiotic differentiation

    Use of Elderly Donors in Liver Transplantation: A Paired-match Analysis at a Single Center

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    OBJECTIVE: To evaluate the use of elderly donors in liver transplantation (LT) and identify risk factors associated with a worse outcome. SUMMARY BACKGROUND DATA: Use of livers from very old donors could expand the donor pool but is not universally implemented. METHODS: This is a retrospective, single-center medical record review. From January 2001 to December 2014, 1354 LTs were performed. After exclusion of donors <18 years, ABO-incompatible LT, re-LT and UNOS 1 status patients, LT recipients were stratified into 2 groups based on donor age: 18-69 (n=692) vs. ≥70 years (n=515) then matched using a propensity score approach. Two groups were finally matched (young group = 448 cases; old group = 515 cases). RESULTS: The median (interquartile range [IQR]) follow-up was 5.0 (2.0-8.4) years. Comparing the 2 identified groups, no differences were observed regarding early retransplants (1.8 vs. 2.9; P = 0.3), HCV-related death (7.6 vs. 8.7%; P = 0.6), vascular (5.8 vs. 5.0%; P = 0.7), and biliary complications (16.5 vs. 18.6%; P = 0.4). On multivariate analysis, independent risk factors for graft loss were: HCV-positive recipient (HR = 2.1; 95% CI = 1.6-2.7; P < 0.001), donor age (HR = 1.0; 95% CI = 1.0-1.0; P < 0.001), cold ischemia time (HR = 1.0; 95% CI = 1.0-1.0; P = 0.042), and donor history of diabetes mellitus (HR = 1.48; 95% CI = 1.03-2.13; P = 0.036). CONCLUSIONS: Use of elderly donors is not associated per se with an increased risk of vascular and biliary complications. In the presence of cold ischemia time and diabetes mellitus, appropriate donor-to-recipient matching is warranted

    High-pressure behaviour of GeO2: a simulation study

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    In this work we study the high pressure behaviour of liquid and glassy GeO2 by means of molecular dynamics simulations. The interaction potential, which includes dipole polarization effects, was parameterized from first-principles calculations. Our simulations reproduce the most recent experimental data to a high degree of precision. The proportion of the various GeOn polyhedra is determined as a function of the pressure: a smooth transition from tetrahedral to octahedral network is observed. Finally, the study of high-pressure, liquid germania confirms that this material presents an anomalous behaviour of the diffusivity as observed in analog systems such as silica and water. The importance of penta-coordinated germanium ions for such behaviour is stressed.Comment: 16 pages, 4 figures, accepted as a Fast Track Communication on Journal of Physics: Condensed Matte

    Abnormal hyperventilation in patients with hepatic cirrhosis: Role of enhanced chemosensitivity to carbon dioxide

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    BACKGROUND: Patients with hepatic cirrhosis frequently show idiopathic hyperventilation at rest, despite no concomitant cardiopulmonary disease. The aim of the study was to determine whether altered chemosensitivity either to hypoxia or hypercapnia could underlie inappropriate hyperventilation in cirrhotic patients. METHODS: We consecutively recruited 30 biopsy proven cirrhotic patients equally distributed in the three Child's classes A, B and C (age 54±8years, mean±SD). All patients underwent evaluation of chemosensitivity to hypoxia and to hypercapnia and blood sampling for brain natriuretic peptide, norepinephrine and progesterone, besides full clinical characterization. We also recruited 10 age- and gender-matched healthy controls (age 55±7years). RESULTS: Overall, 18 patients (60%) showed an increased chemosensitivity to carbon dioxide (CO(2)), while 8 patients (27%) showed enhanced chemosensitivity to hypoxia. Child's class C patients had lower arterial partial pressure of CO(2) (PaCO(2)), higher rest ventilation, increased chemosensitivity to hypercapnia, plasma level of norepinephrine and serum progesterone levels when compared to class A patients and controls (all p<0.05). Rest ventilation was positively related to pH (R=0.41, p=0.023), chemosensitivity to hypercapnia (R=0.54, p=0.002), and progesterone (R=0.53, p=0.016) and negatively to PaCO(2) (R=0.61, p<0.001), but not to hemoglobin level and chemosensitivity to hypoxia. Chemosensitivity to hypercapnia was positively related to PaCO(2) (R=0.74, p<0.001), serum progesterone (R=0.50, p=0.016), and to plasma norepinephrine (R=0.57, p=0.004). CONCLUSIONS: Enhanced chemosensitivity to hypercapnia was found in more decompensated cirrhotic patients and was associated with sympathetic overactivity and elevated serum progesterone, likely representing a key mechanism underlying the "unexplained" hyperventilation observed in such patients

    Transjugular intrahepatic portosystemic shunt for hepatitis C virus-related portal hypertension after liver transplantation.

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    hinolfi D, De Simone P, Catalano G, Petruccelli S, Coletti L, Carrai P, Marti J, Tincani G, Cicorelli A, Cioni R, Filipponi F. Transjugular intrahepatic portosystemic shunt for hepatitis C virus-related portal hypertension after liver transplantation. Clin Transplant 2012 DOI: 10.1111/j.1399-0012.2011.01595.x. © 2012 John Wiley & Sons A/S. Abstract:  This is a single center retrospective review of 19 consecutive liver transplant (LT) patients with hepatitis C virus (HCV)-related graft recurrent hepatitis who underwent transjugular intrahepatic portosystemic shunt (TIPS) at a median interval of 21 months (range: 5-50) from LT. Indications were refractory ascites in 11 patients (57.9%), hydrothorax in six (31.6%), and both in two (10.5%). TIPS was successful in 94.7% of cases (18/19) with only one procedure-related mortality (5.3%) owing to sepsis on day 35. At a median follow-up of 23 months (range: one month-nine yr), TIPS allowed for symptoms resolution in 16 patients (84.2%), with ascites resolving in all cases and hydrothorax persisting in 2. Post-TIPS patient survival at six months, one yr, and three yr was 84.2%, 73.7%, and 56.8%, respectively. We compared these results with a control group of 29 patients with HCV recurrence but without unresponsive ascites or hydrothorax. Patients in the control group had better survival than patients undergoing TIPS placement. However, survival of TIPS patients with a MELD score lower than or equal to 12 was similar to that of the control group. We conclude that TIPS may be used to treat complications secondary to HCV

    Post-transplant liver graft schistosomiasis in a migrant from sub-saharan africa.

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    We report a case of post-transplant liver graft infection with Schistosoma spp in a migrant from sub-Saharan Africa transplanted for HBV-related cirrhosis and with undiagnosed schistosomiasis pre-transplantation. The occurrence of tropical diseases in non-endemic areas warrants screening protocols for organ donors and recipients with a history of exposure in endemic areas
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