218 research outputs found

    Impact of off-shell dynamics on the transport properties and the dynamical evolution of Charm Quarks at RHIC and LHC temperatures

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    We evaluate drag and diffusion transport coefficients comparing a quasi-particle approximation with on-shell constituents of the QGP medium and a dynamical quasi-particles model with off-shell bulk medium at finite temperature T. We study the effects of the width γ\gamma of the particles of the bulk medium on the charm quark transport properties exploring the range where γ<Mq,g\gamma < M_{q,g}. We find that off-shell effects are in general quite moderate and can induce a reduction of the drag coefficient at low momenta that disappear already at moderate momenta, p≳2−3 GeVp \gtrsim 2-3\, \rm GeV. We also observe a moderate reduction of the breaking of the Fluctuation-Dissipation theorem (FDT) at finite momenta. Moreover, we have performed a first study of the dynamical evolution of HQ elastic energy loss in a bulk medium at fixed temperature extending the Boltzmann (BM) collision integral to include off-shell dynamics. A comparison among the Langevin dynamics, the BM collisional integral with on-shell and the BM extension to off-shell dynamics shows that the evolution of charm energy when off-shell effects are included remain quite similar to the case of the on-shell BM collision integral.Comment: 13 pages, 14 figure

    "Chemical" composition of the Quark Gluon Plasma

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    In this article we discuss the issue of the quark to gluon ratio in the Quark Gluon Plasma (QGP). Our model to describe the QGP evolution is based on transport theory including the mean field dynamics described by a quasi-particle model.The last is able to take into account for the lattice QCD thermodynamics and implies a "chemical" equilibrium ratio between quarks and gluons strongly increasing as T approaches to the temperature of the phase transition Tc. We present first the tests performed in a fixed box to check that our code is able to reproduce the equilibrium ratio and then the results obtained for the simulations of ultra-Relativistic Heavy Ion Collisions (uRHIC's) at RHIC and LHC energies. We observe a rapid evolution from a gluon dominated initial state to a quark dominated plasma and we see that near Tc almost 80% of the particles composing the plasma are quarks. This has potentially a strong impact on several quantitative aspects of QGP probes and furnishes a justification to the coalescence hadronization model

    Quinine sulfate and bacterial invasion

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    BACKGROUND: As many patients who receive antimalarial drugs for treatment of noninfectious, inflammatory diseases are also immunosuppressed and might have a concomitant bacterial infection, we studied the effectiveness of these drugs against bacterial infections, to find out whether they could protect against (and even treat) such conditions and obviate the need for an additional antibiotic drug. METHODS: Effect of QS on bacterial growth: Escherichia coli (E. coli) HB101 pRI203 were cultured overnight at 37°C in TSB and inoculated (approx 1 × 10(7) cells /ml) in MEM in the presence of QS at various concentrations (0, 50 and 100 μM). The effect of QS at concentration of 50 and 100 μM on the entry process of E. coli HB101 pRI203 into HeLa cells was studied under different experimental conditions: 1. QS was incubated with 3 × 10(5) HeLa cells for 60 min at 37°C prior to infection. 2. QS was added to HeLa cell monolayers during the infection period. RESULTS: QS showed no antibacterial activity after 24 h of incubation. The invasive efficiency of the bacteria was significantly inhibited at a dose-dependent manner, when QS was added to HeLa cells for 60 min at 37°C prior to infection (condition 1), and to a lesser extent when added during the period of infection (condition 2). CONCLUSIONS: Although the antimalarials are generally regarded as being inactive against most extracellular bacterial species, our results indicate that QS significantly inhibited the internalization/invasion efficacy of E. coli in the host cells

    Shear viscosity and chemical equilibration of the QGP

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    We have investigated, in the frame work of the transport approach, different aspects of the QGP created in Heavy Ion Collisions at RHIC and LHC energies. The shear viscosity η\eta has been calculated by using the Green-Kubo relation at the cascade level. We have compared the numerical results for η\eta obtained from the Green-Kubo correlator with the analytical formula in both the Relaxation Time Approximation (RTA) and the Chapman-Enskog approximation (CE). From this comparison we show that in the range of temperature explored in a Heavy Ion collision the RTA underestimates the viscosity by about a factor of 2, while a good agreement is found between the CE approximation and Gree-Kubo relation already at first order of approximation. The agreement with the CE approximation supplies an analytical formula that allows to develop kinetic transport theory at fixed shear viscosity to entropy density ratio, η/s\eta/s. We show some results for the build up of anisotropic flows v2v_{2} in a transport approach at fixed shear viscosity to entropy density ratio, η/s\eta/s. We study the impact of a T-dependent η/s(T)\eta/s(T) on the generation of the elliptic flows at both RHIC and LHC. We show that the transport approach provides, in a unified way, a tool able to naturally describe the v2(pT)v_{2}(p_{T}) in a wide range of pTp_{T}, including also the description of the rise and fall and saturation of the v2(pT)v_{2}(p_{T}) observed at LHC. Finally, we have studied the evolution of the quark-gluon composition employing a Boltzmann-Vlasov transport approach that include: the mean fields dynamics, associated to the quasi-particle model, and the elastic and inelastic collisions for massive quarks and gluons. Following the chemical evolution from an initial gluon dominated plasma we predict a quark dominance close to TCT_{C} paving the way to an hadronization via quark coalescence.Comment: 15 pages, 10 figures, Invited Talk given by S. Plumari at the 11th International Conference on Nucleus-Nucleus Collisions (NN2012), San Antonio, Texas, USA, May 27-June 1, 2012. To appear in the NN2012 Proceedings in Journal of Physics: Conference Series (JPCS

    Circulating Levels of Ferritin, RDW, PTLs as Predictive Biomarkers of Postoperative Atrial Fibrillation Risk after Cardiac Surgery in Extracorporeal Circulation

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    Postoperative atrial fibrillation (POAF) is the most common arrhythmia after cardiac surgery in conventional extracorporeal circulation (CECC), with an incidence of 15-50%. The POAF pathophysiology is not known, and no blood biomarkers exist. However, an association between increased ferritin levels and increased AF risk, has been demonstrated. Based on such evidence, here, we evaluated the effectiveness of ferritin and other haematological parameters as POAF risk biomarkers in patients subjected to cardiac surgery. We enrolled 105 patients (mean age = 70.1 +/- 7.1 years; 70 men and 35 females) with diverse heart pathologies and who were subjected to cardiothoracic surgery. Their blood samples were collected and used to determine hematological parameters. Electrocardiographic and echocardiographic parameters were also evaluated. The data obtained demonstrated significantly higher levels of serum ferritin, red cell distribution width (RDW), and platelets (PLTs) in POAF patients. However, the serum ferritin resulted to be the independent factor associated with the onset POAF risk. Thus, we detected the ferritin cut-off value, which, when &gt;= 148.5 ng/mL, identifies the subjects at the highest POAF risk, and with abnormal ECG atrial parameters, such as PW indices, and altered structural heart disease variables. Serum ferritin, RDW, and PTLs represent predictive biomarkers of POAF after cardiothoracic surgery in CECC; particularly, serum ferritin combined with anormal PW indices and structural heart disease variables can represent an optimal tool for predicting not only POAF, but also the eventual stroke onset

    Immuno-Assessment of «Pseudomonas syringae» Lipodepsipeptides (Syringomycins and Syringopeptins)

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    Following a previous work on the immunological detection of syringopeptins (SPs), polyclonal antibodies with a high specificity for syringomycins (SRs) were raised in rabbits and purified. Assayed in a competitive ELISA, the most common forms of SR, i.e. SR-E and SR-G, were recognised with a detection limit of 0.1 mg per well, whereas other structurally related bacterial lipodepsipeptides (LDP), such as SPs, pseudomycins (PSs) and syringotoxins (STs) were not recognised. The immuno-assay (competitive ELISA) method developed in this work is about 100 times more sensitive than the current chromatographic (HPLC) method and requires no previous extraction of the toxin. The production of LDP in culture by strains of three pathovars of Pseudomonas syringae (pv. aptata, pv. lachrymans and pv. syringae) was found to range from 0.026 to 0.055 mg ml-1 for SRs and from 0.02 to 0.06 mg ml-1 for SPs. Both the concentration of LDP in aqueous extracts from zucchini cotyledons infected by P. syringae pv. lachrymans and the severity of symptoms were shown to increase progressively after infection. The immunologically estimated concentration of SRs in the infected cotyledons averaged 0.22 mg g-1 f wt after 12 hours, and 0.39 mg g-1 after 4 days. The corresponding values for SPs were 0.11 and 0.37 mg g-1. In a recovery experiment, solutions of pure toxins (0.22 mg SR-E and 0.14 mg SP25A g-1 f wt) were injected in healthy cotyledons. After 2 days, overestimation due to toxin complexing in planta was of 10% for (SR-E) and 40% for (SP25A). Applying these percentages to the values estimated for infected cotyledons, the net concentrations were as follows: 12 h after inoculation: 0.20 (SRs) and 0.07 (SPs) mg g-1 f wt; four days after inoculation: 0.35 (SRs) and 0.22 (SPs) mg g-1 f wt. The values obtained with aqueous extracts from infected plants are relatively high if compared to the figures of the in vitro experiments. It is assumed that the high reactivity of ELISA to the immune-LDP-related compounds present in the water extracts from infected plants is due to the presence of high molecular weight LDP complexes having a cross-reactivity with antibodies substantially higher than that of free toxins

    budget impact analysis of a biosynthetic mesh for incisional hernia repair

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    Abstract Purpose With the development of newer prostheses for hernia repair, it is nowadays difficult to understand the total cost of managing patients treated with these advanced medical devices, especially in the complex abdomen, in which various complications may occur. The aim of this study was to determine the economic implications of these prostheses in order to inform decision making in the management of incisional hernia repair. Methods A budget impact analysis model was developed to evaluate the economic consequences related to the management of patients undergoing complex (Centers for Disease Control and Prevention wound class II–III or Ventral Hernia Working Group grade 2/3) incisional hernia repair through biosynthetic, synthetic, or biological meshes, from the hospital perspective in Italy. The model was populated with complication rates mainly retrieved from the literature to compare the current scenario with 60%, 10%, and 30% rates of synthetic, biosynthetic, and biological mesh utilization, respectively, with future hypothetical scenarios that consider increasing rates of biosynthetic mesh utilization with respect to the other types of mesh in the next 5 years. Hospital costs of the different events were estimated based on health care resource consumption derived from an electronic survey addressed to key opinion leaders in the field. Findings The analysis compared the current scenario with future hypothetical scenarios that consider increasing utilization rates of biosynthetic meshes of 25%, 38%, and 44% in the next 1, 3, and 5 years, as estimated by clinicians. Considering 40,000 incisional hernia repairs per year, an increasing use of the biosynthetic meshes may result in a decrease in the total hospital budget of about €153 million in the next 5 years, with a savings per patient of about €770. Implications The findings of this study support the use of biosynthetic meshes for complex abdominal wall repairs in Italy, showing a potential decrease in the hospital budget in Italy after the diffusion of the new biosynthetic prostheses. Further studies and data from clinical practice would provide additional information to increase the understanding of the economic sustainability of these advanced devices

    Clinical Impact of Pretransplant Multidrug-Resistant Gram-Negative Colonization in Autologous and Allogeneic Hematopoietic Stem Cell Transplantation

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    Abstract Multidrug-resistant Gram-negative bacteria (MDR-GNB) are an emerging cause of morbidity and mortality after hematopoietic stem cell transplantation (HSCT). Three-hundred forty-eight consecutive patients transplanted at our hospital from July 2012 to January 2016 were screened for a pretransplant MDR-GNB colonization and evaluated for clinical outcomes. A pretransplant MDR-GNB colonization was found in 16.9% of allo-HSCT and in 9.6% of auto-HSCT recipients. Both in auto- and in allo-HSCT, carriers of a MDR-GNB showed no significant differences in overall survival (OS), transplant-related mortality (TRM), or infection-related mortality (IRM) compared with noncarriers. OS at 2 years for carriers compared with noncarriers was 85% versus 81% ( P  = .262) in auto-HSCT and 50% versus 43% ( P  = .091) in allo-HSCT. TRM at 2 years was 14% versus 5% ( P  = .405) in auto-HSCT and 31% versus 25% ( P  = .301) in allo-HSCT. IRM at 2 years was 14% versus 2% ( P  = .142) in auto-HSCT and 23% versus 14% ( P  = .304) in allo-HSCT. In multivariate analysis, only grade III to IV acute graft-versus-host disease was an independent factor for reduced OS ( P P P P  = .207). We conclude that in this extended single-center experience, a pretransplant MDR-GNB colonization did not significantly influence OS, TRM, and IRM both in auto- and allo-HSCT settings and that MDR-GNB attributed mortality can be controlled in carriers when an early pre-emptive antimicrobial therapy is started in case of neutropenic fever

    a new clinicobiological scoring system for the prediction of infection related mortality and survival after allogeneic hematopoietic stem cell transplantation

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    Abstract Infection-related mortality (IRM) is a substantial component of nonrelapse mortality (NRM) after allogeneic hematopoietic stem cell transplantation (allo-HSCT). No scores have been developed to predict IRM before transplantation. Pretransplantation clinical and biochemical data were collected from a study cohort of 607 adult patients undergoing allo-HSCT between January 2009 and February 2017. In a training set of 273 patients, multivariate analysis revealed that age >60 years ( P  = .003), cytomegalovirus host/donor serostatus different from negative/negative ( P P  = .004), and pretransplantation IgM level P  = .028) were independent predictors of increased IRM. Based on these results, we developed and subsequently validated a 3-tiered weighted prognostic index for IRM in a retrospective set of patients (n = 219) and a prospective set of patients (n = 115). Patients were assigned to 3 different IRM risk classes based on this index score. The score significantly predicted IRM in the training set, retrospective validation set, and prospective validation set ( P P P
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