3,607 research outputs found

    Search for the Higgs Boson in the Channel H->ZZ*->4l with the ATLAS Detector

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    The decay channel H->ZZ*->4l provides a clean signature for the Higgs boson in the mass range between ~120 GeV and 2MZ, above which the "gold-plated" channel with two real Z bosons in the final state opens up. The signal cross section is several orders of magnitude smaller than those for the backgrounds, therefore a thorough understanding of the multi-lepton processes is needed to obtain a high background rejection. Crucial for this channel is also a very good knowledge of the trigger and detector response for lepton identification and reconstruction. The observability of the signal on top of the reducible tt, Zbb and of the irreducible ZZz backgrounds with the ATLAS Detector is discussed in the following, with particular emphasis on lepton reconstruction. The ATLAS discovery potential for the H->4l, including the most realistic and up-to-date description of the detector performance, is presented

    Search for the Higgs Boson in the Channel H→ZZ(*)→4l with the ATLAS Detector

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    The decay channel H→ZZ(∗)→4ℓ provides a clean signature for the Higgs boson in the mass range between ∌120 GeV/c2 and 2MZ, above which the gold-plated channel with two real Z bosons in the ïŹnal state opens up. The signal cross section is several orders of magnitude smaller than those for the backgrounds, therefore a thorough understanding of the multi-lepton processes is needed to obtain a high background rejection. Crucial for this channel is a very good understanding of the trigger and detector response for lepton identiïŹcation and reconstruction. In order to compute an exclusion limit, a good knowledge of the back- grounds as well as of the signal selection efficiency after all analysis cut is needed. The observability of the signal on top of the reducible tÂŻt, ZbÂŻb and W Z and of the irreducible Z Z backgrounds is discussed in detail, with particular emphasis on the lepton reconstruction. We evaluate the ATLAS discovery potential for the H → 4ℓ channel, including the most realistic and up-to-date description of the detector performance

    Multimodal treatment for local recurrent malignant gliomas: resurgery and/or reirradiation followed by chemotherapy

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    The therapeutic management of recurrent malignant gliomas (MGs) is not determined. Therefore, the efficacy of a multimodal approach and a combination systemic therapy was investigated. A retrospective analysis of 26 MGs patients at first relapse treated with multimodal therapy (chemotherapy plus surgery and/or reirradiation) or chemotherapy alone was performed. Second-line chemotherapy consisted of fotemustine (FTM) in combination with bevacizumab (BEV) (cFTM/BEV) or followed by third-line BEV (sFTM/BEV). Subgroup analyses were performed. Multimodal therapy provided a higher overall response rate (ORR) (73 vs. 47%), disease control rate (DCR) (82 vs. 67%), median progression-free survival (mPFS) (11 vs. 7 months; P=0.08) and median overall survival (mOS) (13 vs. 8 months; P=0.04) compared with chemotherapy. Concomitant FTM/BEV resulted in higher ORR (84 vs. 36%), DCR (92 vs. 57%), mPFS (10 vs. 5 months; P=0.22) and mOS (11 vs. 5.2 months; P=0.15) compared with sFTM/BEV. Methylated patients did not experience additional survival benefits with multimodality treatment but had higher mPFS (10 vs 7.1 months; P=0.33) and mOS (11 vs. 8 months; P=0.33) with cFTM/BEV. Unmethylated patients experienced the greatest survival benefit with the multimodal approach (mPFS: 10 vs. 5 months; mOS 11 vs 6 months; both P=0.02) and cFTM/BEV (mPFS: 5 vs. 2 months; mOS 6 vs. 3.2 months; both P=0.01). In conclusion, in recurrent MGs, multimodal therapy and cFTM/BEV provide survival and response benefits. Methylated patients benefit from a cFTM/BEV but not from a multimodal approach. Notably, unmethylated patients had the highest survival benefit with the two strategies

    Imaging of the Unstable Shoulder

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    Unstable shoulder can occur in different clinical scenarios with a broad spectrum of symptoms and presentations: first-time (or recurrent) traumatic acute shoulder anterior dislocation or chronic anterior instability after repeated dislocations.Imaging in unstable shoulder is fundamental for choosing the right treatment preventing recurrence.The goal of imaging depends on clinical scenario and patient characteristics

    High field MR microimaging investigation gives more insights on spongy bone characteristics

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    Spongy-bone is a porous system characterized by a solid trabecular network immersed in bonemarrow and characterized by a different relative percentage of water and fats. In our previous paper, we demonstrated using calf bone samples, that water is more prevalent in the boundary zone while fats are rearranged primarily in the central zone of each pore. Moreover we showed that water internal gradient (Gi) magnitude from the samples was directly proportional to their trabecular bone density. Using a 9.4T MR micro-imaging system, here we evaluated T2, T2*, apparent diffusion coefficient (ADC) and Gi parameters from in vitro calf samples in spatially resolved modality, for both water and fat components. Moreover, relative percentages of water and fats were quantified from spectra. T2, T2* and ADC values are higher in fat than in water component. Moreover, the differential effects of fat and water diffusion result in different T2 and Gi behaviours. Our results suggest that differently from fat parameters, water T2*, ADC and Gi, may be reliable markers to assess not only trabecular bone density but, more generally, the status of spongy bone

    Therapeutic approach in glioblastoma multiforme with primitive neuroectodermal tumor components: case report and review of the literature

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    Glioblastoma multiforme (GBM) is the most common and aggressive malignant glioma that is treated with first-line therapy, using surgical resection followed by local radiotherapy and concomitant/adjuvant temozolomide (TMZ) treatment. GBM is characterised by a high local recurrence rate and a low response to therapy. Primitive neuroectodermal tumour (PNET) of the brain revealed a low local recurrence rate; however, it also exhibited a high risk of cerebrospinal fluid (CSF) dissemination. PNET is treated with surgery followed by craniospinal irradiation (CSI) and platinum-based chemotherapy in order to prevent CSF dissemination. GBM with PNET-like components (GBM/PNET) is an emerging variant of GBM, characterised by a PNET-like clinical behaviour with an increased risk of CSF dissemination; it also may benefit from platinum-based chemotherapy upfront or following failure of GBM therapy. The results presented regarding the management of GBM/PNET are based on case reports or case series, so a standard therapeutic approach for GBM/PNET is not defined, constituing a challenging diagnostic and therapeutic dilemma. In this report, a case of a recurrent GBM/PNET treated with surgical resection and radiochemotherapy as Stupp protocol, and successive platinum-based chemotherapy due to the development of leptomeningeal dissemintation and an extracranial metastasis, is discussed. A review of the main papers regarding this rare GBM variant and its therapeutic approach are also reported. In conclusion, GBM/PNET should be treated with a multimodal approach including surgery, chemoradiotherapy, and/or the early introduction of CSI and platinum-based chemotherapy upfront or at recurrence

    Cantori and dynamical localization in the Bunimovich Stadium

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    Classical and quantum properties of the Bunimovich stadium in the diffusive regime are reviewed. In particular, the quantum properties are directly investigated using an approximate quantum map. Different localized regimes are found, namely, perturbative, quasi-integrable (due to classical Cantori), dynamical and ergodic.Comment: RevTeX, 8 pages, to be published in Physica

    Rationale, experimental data, and emerging clinical evidence on early and preventive use of levosimendan in patients with ventricular dysfunction

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    Acute ventricular dysfunction (AVD) is a complex condition with substantial morbidity and mortality, still featuring unique therapeutic challenges. Levosimendan is a calcium sensitizer and ATP-dependent potassium channel opener that was developed as an inodilating drug for the treatment of acute heart failure and cardiogenic shock. Differently from other more widely used inotropic agents, levosimendan has some exclusive characteristics, in terms of mechanisms of action, pharmacodynamic profile, and haemodynamic effects. This may have important clinical implications. In particular, in patients with AVD or in patients with pre-existing severe ventricular impairment undergoing planned myocardial stress, the administration of levosimendan before the onset of overt symptoms or before cardiovascular therapeutic procedures may have the potential to bridge the patient through the critical phase. In this review, we will focus on the rationale, the existing experimental data, and the emerging clinical experience supporting an early, even preventive use of levosimendan in severe ventricular dysfunction, beyond its recognized indications
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