2,648 research outputs found

    Longtitudinal electron beam diagnostics via upconversion of THz to visible radiation

    Get PDF
    Longitudinal electro-optic electron bunch diagnostics has been successfully applied at several accelerators. The electro-optic effect can be seen as an upconversion of the Coulomb field of the relativistic electron bunch (THz radiation) to the visible spectral range, where a variety of standard diagnostic tools are available. Standard techniques to characterise femtosecond optical laser pulses (auto- and cross-correlators) have led to the schemes that can measure electron bunch profiles with femtosecond resolution. These techniques require, however, well synchronized femtosecond laser pulses, in order to obtain the desired temporal resolution. Currently, we are exploring other electro-optic variants which require less advanced laser systems and will be more amenable to beam based longitudinal feedback applications. The first results of one such new scheme will be presented in this paper

    Dynamics of vibrofluidized granular gases in periodic structures

    Full text link
    The behavior of a driven granular gas in a container consisting of MM connected compartments is studied employing a microscopic kinetic model. After obtaining the governing equations for the occupation numbers and the granular temperatures of each compartment we consider the various dynamical regimes. The system displays interesting analogies with the ordering processes of phase separating mixtures quenched below the their critical point. In particular, we show that below a certain value of the driving intensity the populations of the various compartments become unequal and the system clusterizes. Such a phenomenon is not instantaneous, but is characterized by a time scale, τ\tau, which follows a Vogel-Vulcher exponential behavior. On the other hand, the reverse phenomenon which involves the ``evaporation'' of a cluster due to the driving force is also characterized by a second time scale which diverges at the limit of stability of the cluster.Comment: 11 pages, 17 figure

    Anti-thymocyte globulin with CsA and MMF as GVHD prophylaxis in nonmyeloablative HLA-mismatched allogeneic HCT

    Get PDF
    Nonmyeloablative regimens are used for allogeneic hematopoietic cell transplantation (HCT) of older or medically unfit patients, but successful outcome is still hindered by graft-versus-host disease (GVHD), especially in the setting of HLA-mismatched HCT. New GVHD prophylaxis strategies are emerging, including the triple drug strategy, that improve the GVHD-free and relapse-free survival (GRFS). Because the impact of ATG in HLA-mismatched Flu-TBI-based nonmyeloablative HCT has not been investigated, we did a retrospective analysis in three Dutch centers. 67 patients were evaluable, with a median age of 56 years. Overall survival, relapse-free survival and GRFS at 4 years were 52%, 43%, and 38%, respectively. NRM findings and cumulative incidence of relapse at 4 years were 26% and 31%, respectively. At 1-year grade II-IV had occurred in 40% of the patients, and the incidence of moderate-severe chronic GVHD incidence was 16%. Acknowledging the limitations of retrospective analyses, we conclude that the use of ATG for HLA-mismatched truly nonmyeloablative Flu-TBI HCT is feasible and results in acceptable long term outcomes, especially with regards to GRFS. We consider ATG in combination with cyclosporin and mycophenolate mofetil as an alternative for the triple drug strategy that uses sirolimus for GVHD prophylaxis in this particular setting

    Reduced chance of hearing loss associated with Therapeutic Drug Monitoring of Aminoglycosides in the treatment of Multidrug Resistant Tuberculosis

    Get PDF
    Item does not contain fulltextHearing loss and nephrotoxicity are associated with prolonged treatment duration and higher dosage of amikacin and kanamycin. In our tuberculosis center, we used therapeutic drug monitoring (TDM) targeting preset pharmacokinetic/pharmacodynamic (PK/PD) surrogate endpoints in an attempt to maintain efficacy while preventing (oto)toxicity. To evaluate this strategy, we retrospectively evaluated medical charts of tuberculosis (TB) patients treated with amikacin or kanamycin in the period from 2000 to 2012. Patients with culture-confirmed multiresistant or extensively drug-resistant tuberculosis (MDR/XDR-TB) receiving amikacin or kanamycin as part of their TB treatment for at least 3 days were eligible for inclusion in this retrospective study. Clinical data, including maximum concentration (Cmax), Cmin, and audiometry data, were extracted from the patients' medical charts. A total of 80 patients met the inclusion criteria. The mean weighted Cmax/MIC ratios obtained from 57 patients were 31.2 for amikacin and 12.3 for kanamycin. The extent of hearing loss was limited and correlated with the cumulative drug dose per kg of body weight during daily administration. At follow-up, 35 (67.3%) of all patients had successful outcome; there were no relapses. At a median dose of 6.5 mg/kg, a correlation was found between the dose per kg of body weight during daily dosing and the extent of hearing loss in dB at 8,000 Hz. These findings suggest that the efficacy at this lower dosage is maintained with limited toxicity. A randomized controlled trial should provide final proof of the safety and efficacy of TDM-guided use of aminoglycosides in MDR-TB treatment

    Electro-optic techniques for longitudinal electron bunch diagnostics

    Get PDF
    Electro-optic techniques are becoming increasingly important in ultrafast electron bunch longitudinal diagnostics and have been successfully implemented at various accelerator laboratories. The longitudinal bunch shape is directly obtained from a single-shot, non-intrusive measurement of the temporal electric field profile of the bunch. Further- more, the same electro-optic techniques can be used to measure the temporal profile of terahertz / far-infrared opti- cal pulses generated by a CTR screen, at a bending magnet (CSR), or by an FEL. This contribution summarizes the re- sults obtained at FELIX and FLASH

    Fetal loss in women with hereditary thrombophilic defects and concomitance of other thrombophilic defects:a retrospective family study

    Get PDF
    Objective To assess the absolute risk of fetal loss associated with hereditary deficiencies of antithrombin (AT), protein C (PC) and protein S (PS), and the contribution of additional thrombophilic defects to this risk. Design A retrospective family cohort study. Setting A tertiary referral teaching hospital. Population Women from families with hereditary deficiencies of AT, PC and PS, and their non-deficient relatives. Methods We assessed the absolute risk of fetal loss, comparing deficient women with non-deficient female relatives. Main outcome measures Early, late and total fetal loss rates; odds ratios of fetal loss. Results We evaluated 289 women, who had 860 pregnancies. The total fetal loss rates were 23% (AT deficient), 26% (PC deficient), 11% (type-I PS deficient) and 15% (type-III PS deficient), compared with 11, 18, 12 and 13% in non-deficient women, respectively. Odds ratios were 2.3 (95% CI 0.9-6.1), 2.1 (95% CI 0.9-4.7), 0.7 (95% CI 0.2-1.8) and 1.1 (95% CI 0.6-2.0), none of which reached statistical significance. Differences were mainly the result of higher late fetal loss rates in women deficient in AT (OR 11.3, 95% CI 3.0-42.0) and PC (OR 4.7, 95% CI 1.3-17.4). The concomitance of factor-V Leiden and prothrombin G20210A was observed in 19% of women, and did not increase the risk of fetal loss. Conclusions Although absolute risks of fetal loss were high, odds ratios of total fetal loss were not statistically significant in deficient versus non-deficient women. However the higher absolute risks appeared to reflect higher late fetal loss rates as opposed to early fetal loss rates. An additional effect of concomitance of factor-V Leiden and prothrombin G20210A was not demonstrated, which may result from the exclusion of women at highest risk of venous thromboembolism, or from the small numbers sampled in the study

    The Active Recovery Triad (ART) model:A new approach in Dutch long-term mental health care

    Get PDF
    Unlike developments in short-term clinical and community care, the recovery movement has not yet gained foothold in long-term mental health services. In the Netherlands, approximately 21,000 people are dependent on long-term mental health care and support. To date, these people have benefited little from recovery-oriented care, rather traditional problem-oriented care has remained the dominant approach. Based on the view that recovery is within reach, also for people with complex needs, a new care model for long-term mental health care was developed, the active recovery triad (ART) model. In a period of 2.5 years, several meetings with a large group of stakeholders in the field of Dutch long-term mental health care took place in order to develop the ART model. Stakeholders involved in the development process were mental health workers, policy advisors, managers, directors, researchers, peer workers, and family representatives. The ART model combines an active role for professionals, service users, and significant others, with focus on recovery and cooperation between service users, family, and professionals in the triad. The principles of ART are translated into seven crucial steps in care and a model fidelity scale in order to provide practical guidelines for teams implementing the ART model in practice. The ART model provides guidance for tailored recovery-oriented care and support to this “low-volume high-need” group of service users in long-term mental health care, aiming to alter their perspective and take steps in the recovery process. Further research should investigate the effects of the ART model on quality of care, recovery, and autonomy of service users and cooperation in the triad

    Coarsening of Sand Ripples in Mass Transfer Models with Extinction

    Full text link
    Coarsening of sand ripples is studied in a one-dimensional stochastic model, where neighboring ripples exchange mass with algebraic rates, Γ(m)mγ\Gamma(m) \sim m^\gamma, and ripples of zero mass are removed from the system. For γ<0\gamma < 0 ripples vanish through rare fluctuations and the average ripples mass grows as \avem(t) \sim -\gamma^{-1} \ln (t). Temporal correlations decay as t1/2t^{-1/2} or t2/3t^{-2/3} depending on the symmetry of the mass transfer, and asymptotically the system is characterized by a product measure. The stationary ripple mass distribution is obtained exactly. For γ>0\gamma > 0 ripple evolution is linearly unstable, and the noise in the dynamics is irrelevant. For γ=1\gamma = 1 the problem is solved on the mean field level, but the mean-field theory does not adequately describe the full behavior of the coarsening. In particular, it fails to account for the numerically observed universality with respect to the initial ripple size distribution. The results are not restricted to sand ripple evolution since the model can be mapped to zero range processes, urn models, exclusion processes, and cluster-cluster aggregation.Comment: 10 pages, 8 figures, RevTeX4, submitted to Phys. Rev.
    corecore