459 research outputs found

    Next-to-Leading Order QCD Corrections to Spectator Effects in Lifetimes of Beauty Hadrons

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    Theoretical predictions of beauty hadron lifetimes, based on the heavy quark expansion up to and including order 1/mb^2, do not to reproduce the experimental measurements of the lifetime ratios tau(B+)/tau(Bd) and tau(Lambdab)/tau(Bd). Large corrections to these predictions come from phase-space enhanced 1/mb^3 contributions, i.e. hard spectator effects. In this paper we calculate the next-to-leading order QCD corrections to the Wilson coefficients of the local operators appearing at O(1/mb^3). We find that these corrections improve the agreement with the experimental data. The lifetime ratio of charged to neutral B mesons, tau(B+)/tau(Bd), turns out to be in very good agreement with the corresponding measurement, whereas for tau(Bs)/tau(Bd) and tau(Lambdab)/tau(Bd) there is a residual difference at the 1-sigma level. We discuss, however, why the theoretical predictions are less accurate in the latter cases.Comment: 29 pages, 7 figures, uses epsf. Misprints in eqs. (28) and (52) corrected. Results unchanged. Final version to appear on Nucl.Phys.

    Heterochromatin characterization and ribosomal gene location in two monotypic genera of bloodsucker bugs (Cimicidae, Heteroptera) with holokinetic chromosomes and achiasmatic male meiosis

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    Abstract Members of the family Cimicidae (Heteroptera: Cimicomorpha) are temporary bloodsuckers on birds and bats as primary hosts and humans as secondary hosts. Acanthocrios furnarii (2n = 12 = 10 + XY, male) and Psitticimex uritui (2n = 31 = 28 + X 1 X 2 Y, male) are two monotypic genera of the subfamily Haematosiphoninae, which have achiasmatic male meiosis of collochore type. Here, we examined chromatin organization and constitution of cimicid holokinetic chromosomes by determining the amount, composition and distribution of constitutive heterochromatin, and number and location of nucleolus organizer regions (NORs) in both species. Results showed that these two bloodsucker bugs possess high heterochromatin content and have an achiasmatic male meiosis, in which three regions can be differentiated in each autosomal bivalent: (i) terminal heterochromatic regions in repulsion; (ii) a central region, where the homologous chromosomes are located parallel but without contact between them; and (iii) small areas within the central region, where collochores are detected. Acanthocrios furnarii presented a single NOR on an autosomal pair, whereas P. uritui presented two NORs, one on an autosomal pair and the other on a sex chromosome. All NORs were found to be associated with CMA 3 bright bands, indicating that the whole rDNA repeating unit is rich in G + C base pairs. Based on the variations in the diploid autosomal number, the presence of simple and multiple sex chromosome systems, and the number and location of 18S rDNA loci in the two Cimicidae species studied, we might infer that rDNA clusters and genome are highly dynamic among the representatives of this family

    Postoperative Echocardiographic Reduction of Right Ventricular Function: Is Pericardial Opening Modality the Main Culprit?

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    Echocardiographic reduction of RV function, measured using TAPSE, is a well described phenomenon after cardiac surgery. The aim of the present study was to investigate the relation between the modality of pericardial opening (lateral versus anterior) and the postoperative right ventricular systolic function by comparing echocardiographic parameters in patients undergoing minimally invasive or traditional mitral valve repair. 34 patients with severe mitral regurgitation due to mitral valve prolapse underwent traditional (sternotomy) operation (Group A) or minimally invasive surgery with right anterolateral thoracotomy (Group B). A postoperative TAPSE fall was found in both groups. Group A experienced a significant postoperative TAPSE fall versus Group B with p<0.0001

    Measurement of the leptonic decay widths of the phi-meson with the KLOE detector

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    The phi-meson leptonic widths, Gee and Gmm, are obtained, respectively, from the e+e- forward-backward asymmetry and the muon cross section around the phi-mass energy. We find Gee=1.32&#8853;0.05&#8853;0.03 kev and sqrt(GeeGmm)= 1.320&#8853;0.018&#8853;0.017 kev. These results, compatible with Gee=Gmm, provide a precise test of lepton universality. Combining the two results gives G_lept=1.320&#8853;0.023 kev.Comment: 10 pages and 8 figures to be submitted to Phys.Lett.

    Markers of subclinical atherosclerosis in patients with aortic valve sclerosis : A meta-analysis of literature studies

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    Objective: Growing evidence suggested an association between aortic valve sclerosis (AVSc) and cardiovascular (CV) events. However, little is known about the association of AVSc with major markers of subclinical atherosclerosis. We performed a meta-analysis of literature studies to address this issue. Approach and Results: Studies on the relationship between AVSc and common carotid artery intima-media thickness (IMT), prevalence of carotid plaques (CPs), flow-mediated dilation (FMD), aortic pulse wave velocity (PWV) and augmentation index (AIx) were systematically searched in electronic databases. Thirteen studies enrolling 1086 AVSc patients and 2124 controls were included. Compared to controls, AVSc patients showed higher IMT (MD: 0.32 mm; 95%CI: 0.07, 0.58; p=0.014), and higher prevalence of CPs (OR: 4.06; 95%CI: 2.38, 6.93; p<0.001). Moreover, lower FMD (MD: -4.48%; 95%CI: -7.23, -1.74; p=0.001) and higher PWV (MD: 0.96%; 95%CI: 0.11, 1.81; p=0.027) were found in AVSc subjects than in controls, with no differences in AIx (MD: 0.76%; 95%CI: -0.97, 2.49; p=0.389). In Meta-regression analyses body mass index and triglycerides levels have an impact on the difference in IMT between cases and controls, while male gender and smoking habit were associated with the difference in the prevalence of CPs between the two groups. Conclusion: AVSc is significantly associated with altered markers of subclinical atherosclerosis, thus supporting the concept that AVSc and atherosclerosis share common etiopathological mechanism and/or risk factors. On this basis, an echocardiogram carried out to assess the state of the aortic valve would be desirable whenever an altered subclinical marker of atherosclerosis is found

    The impact of pericardial approach and myocardial protection onto postoperative right ventricle function reduction

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    Background The reduction of RV function after cardiac surgery is a well-known phenomenon. It could persist up-to one year after the operation and often leads to an incomplete recovery at follow-up echocardiographic control. The aim of the present study is to analyze the impact of different modalities of pericardial incision (lateral versus anterior) and of myocardial protection protocols (Buckberg versus Custodiol) onto postoperative RV dynamic by relating two- and three-dimensional echocardiographic parameters in patients undergoing mitral valve repair through minimally invasive or traditional surgery approach. Methods We have analyzed 44 consecutive patients with severe degenerative mitral regurgitation who underwent mitral reparation with different surgical approach and cardioplegia type: Group 1 (17 pts): sternotomy with Buckberg cardioplegia protocol; Group 2 (10 pts): sternotomy with Custodiol cardioplegia; Group 3 (17 pts): mini-invasive surgery with Custodiol cardioplegia. Two-dimensional transthoracic echocardiography was performed pre- and 6 months post-surgery to evaluate RV function by tricuspid annular plane systolic excursion (TAPSE). Results All patients underwent successful and uneventful. A postoperative TAPSE reduction was found in all groups. However, mini-invasive patients experienced a significant reduced variation versus traditional surgery. Conclusions Mini-invasive mitral repair, with lateral incision of pericardium, reduces postoperative TAPSE fall, while cardioplegia protocol fails to have an impact onto longitudinal RV function. In our study, the RV seems to experience a clinically irrelevant geometrical modification too, whose entity appears to be less evident in case of lateral pericardial approach. These results could strengthen the use of minimally invasive approach also to preserve RV function

    Excess of NPM-ALK oncogenic signaling promotes cellular apoptosis and drug dependency.

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    Most of the anaplastic large-cell lymphoma (ALCL) cases carry the t(2;5; p23;q35) that produces the fusion protein NPM-ALK (nucleophosmin-anaplastic lymphoma kinase). NPM-ALK-deregulated kinase activity drives several pathways that support malignant transformation of lymphoma cells. We found that in ALK-rearranged ALCL cell lines, NPM-ALK was distributed in equal amounts between the cytoplasm and the nucleus. Only the cytoplasmic portion was catalytically active in both cell lines and primary ALCL, whereas the nuclear portion was inactive because of heterodimerization with NPM1. Thus, about 50% of the NPM-ALK is not active and sequestered as NPM-ALK/NPM1 heterodimers in the nucleus. Overexpression or relocalization of NPM-ALK to the cytoplasm by NPM genetic knockout or knockdown caused ERK1/2 (extracellular signal-regulated protein kinases 1 and 2) increased phosphorylation and cell death through the engagement of an ATM/Chk2- and γH2AX (phosphorylated H2A histone family member X)-mediated DNA-damage response. Remarkably, human NPM-ALK-amplified cell lines resistant to ALK tyrosine kinase inhibitors (TKIs) underwent apoptosis upon drug withdrawal as a consequence of ERK1/2 hyperactivation. Altogether, these findings indicate that an excess of NPM-ALK activation and signaling induces apoptosis via oncogenic stress responses. A 'drug holiday' where the ALK TKI treatment is suspended could represent a therapeutic option in cells that become resistant by NPM-ALK amplification.We thank Maria Stella Scalzo for technical support, Dr Emanuela Colombo for kindly providing MEFs that lack NPM1 (MEF NPM−/−p53−/−) and control fibroblasts (MEF p53−/−), Dr Guido Serini for the use of his confocal microscopy unit at the Candiolo Cancer Institute—IRCCS, Torino, Italy. We also thank Ariad Pharmaceutical, Pfizer, Astellas and Novartis that kindly provided all drugs used in this study. This work was supported by the Regione Lombardia (ID14546A) and Fondazione Berlucchi Onlus Grant 2014 (to CGP), and by grants FP7 ERC-2009-StG (Proposal No. 242965—‘Lunely’); Associazione Italiana per la Ricerca sul Cancro (AIRC) Grant IG-12023; Koch Institute/DFCC Bridge Project Fund; Ellison Foundation Boston; Worldwide Cancer Research Association (former AICR) grant 12-0216; the Grant for Oncology Innovation by Merck-Serono and R01 CA196703-01 (to RC).This is the author accepted manuscript. The final version is available from NPG via http://dx.doi.org/10.1038/onc.2015.45

    Years of life that could be saved from prevention of hepatocellular carcinoma

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    BACKGROUND: Hepatocellular carcinoma (HCC) causes premature death and loss of life expectancy worldwide. Its primary and secondary prevention can result in a significant number of years of life saved. AIM: To assess how many years of life are lost after HCC diagnosis. METHODS: Data from 5346 patients with first HCC diagnosis were used to estimate lifespan and number of years of life lost after tumour onset, using a semi-parametric extrapolation having as reference an age-, sex- and year-of-onset-matched population derived from national life tables. RESULTS: Between 1986 and 2014, HCC lead to an average of 11.5 years-of-life lost for each patient. The youngest age-quartile group (18-61 years) had the highest number of years-of-life lost, representing approximately 41% of the overall benefit obtainable from prevention. Advancements in HCC management have progressively reduced the number of years-of-life lost from 12.6 years in 1986-1999, to 10.7 in 2000-2006 and 7.4 years in 2007-2014. Currently, an HCC diagnosis when a single tumour <2 cm results in 3.7 years-of-life lost while the diagnosis when a single tumour 65 2 cm or 2/3 nodules still within the Milan criteria, results in 5.0 years-of-life lost, representing the loss of only approximately 5.5% and 7.2%, respectively, of the entire lifespan from birth. CONCLUSIONS: Hepatocellular carcinoma occurrence results in the loss of a considerable number of years-of-life, especially for younger patients. In recent years, the increased possibility of effectively treating this tumour has improved life expectancy, thus reducing years-of-life lost
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