491 research outputs found

    Thermal Ageing of a Hybrid Composite Rod for Next Generation Overhead Power Lines

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    The thermal stability of a hybrid composite rod, made of epoxy-anhydride matrix reinforced with both unidirectional carbon and glass fibers, has been evaluated between 180 and 210 °C in different nitrogen/oxygen gas mixtures with several conventional but complementary laboratory techniques such as Fourier transform infrared spectrometry, thermogravimetry, differential calorimetry, optical microscopy, and three-point bending. Thermolysis predominates in the carbon-fiber core, where it induces an efficient chain scission process, leading to a decrease in the glass transition temperature and the formation of small macromolecular fragments, presumably diacids. These very polar fragments remain trapped in the carbon core, where they initiate micro-cavities when their concentration exceeds the solubility threshold. These micro-cavities accumulate in rich-matrix regions, where they coalesce to form apparent large cracks. They are thus responsible for the catastrophic decrease in elastic and fracture properties of the composite rod. In contrast, thermal oxidation affects a too thin superficial layer (typically 60 ”m) of the glass-fiber shell to change significantly the global mechanical behavior of the composite rod. Based on these experimental observations, a kinetic model has been proposed to predict the initiation and development of damage in the composite rod. Its validity is successfully checked by comparing its predictions with the experimental results

    Metastatic Rhabdomyosarcoma: Results of the European Paediatric Soft Tissue Sarcoma Study Group MTS 2008 Study and Pooled Analysis With the Concurrent BERNIE Study

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    Rabdomiosarcoma metastĂĄsico; Sarcoma de tejido blandoRabdomiosarcoma metastĂ tic; Sarcoma de teixit touMetastatic rhabdomyosarcoma; Soft tissue sarcomaPURPOSE Outcome for patients with metastatic rhabdomyosarcoma (RMS) is poor. This study presents the results of the MTS 2008 study with a pooled analysis including patients from the concurrent BERNIE study. PATIENTS AND METHODS In MTS 2008, patients with metastatic RMS received four cycles of ifosfamide, vincristine, and actinomycin D (IVA) plus doxorubicin, five cycles of IVA, and 12 cycles of maintenance chemotherapy (low-dose cyclophosphamide and vinorelbine). The BERNIE study randomly assigned patients to the addition or not of bevacizumab to the same chemotherapy. Local therapy (surgery/radiotherapy) was given to the primary tumor and all metastatic sites when feasible. RESULTS MTS 2008 included 270 patients (median age, 9.6 years; range, 0.07-20.8 years). With a median follow-up of 50.3 months, 3-year event-free survival (EFS) and overall survival (OS) were 34.9% (95% CI, 29.1 to 40.8) and 47.9% (95% CI, 41.6 to 53.9), respectively. In pooled analyses on 372 patients with a median follow-up of 55.2 months, 3-year EFS and OS were 35.5% (95% CI, 30.4 to 40.6) and 49.3% (95% CI, 43.9 to 54.5), respectively. Patients with ≀ 2 Oberlin risk factors (ORFs) had better outcome than those with ≄ 3 ORFs: 3-year EFS was 46.1% versus 12.5% (P < .0001) and 3-year OS 60.0% versus 26.0% (P < .0001). Induction chemotherapy and maintenance appeared tolerable; however, about two third of patients needed dose adjustments during maintenance. CONCLUSION Outcome remains poor for patients with metastatic RMS and multiple ORFs. Because of the design of the studies, it was not possible to determine whether the intensive induction regimen and/or the addition of maintenance treatment resulted in apparent improvement of outcome compared with historical cohorts. Further studies, with novel treatment approaches are urgently needed, to improve outcome for the group of patients with adverse prognostic factors

    A kinetic model for predicting the oxidative degradation of additive free polyethylene in bleach desinfected water

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    The chemical interactions between additive free PE and bleach were investigated by FTIR spectrophotometry and viscosimetry in molten state after immersion (for a maximum duration of one hundred days) in bleach solutions maintained at a temperature of 60 °C, a free chlorine concentration of 100 ppm, and a pH = 4, 5 or 7. It was found that the polymer undergoes a severe oxidation from the earliest days of exposure in a superficial layer of about 50–100 ÎŒm thick, almost independent of the pH value. In this layer, oxidation leads to the formation and accumulation of various carbonyl products (mostly ketones and carboxylic acids) but also, after about 2–3 weeks of exposure, to a dramatic decrease in the average molar mass due to the large predominance of chain scissions over crosslinking. It was also found that the oxidation rate is maximum at pH = 5, and of the same order of magnitude at pH = 4 and 7. Based on the equilibrium diagram giving access to the relative predominance of the three main chemical species as a function of the pH value of the bleach solution, it was assumed that oxidation is initiated by radical species coming firstly from hypochlorous acid (ClOH) and secondarily from chlorine (Cl2), given that hypochlorite ions (ClO−) are totally insoluble into the PE matrix. In addition, for explaining the surprisingly large value of the oxidized layer thickness despite the high reactivity of the involved radicals, it was assumed that ClOH and Cl2 do not decompose into radicals in the water phase, but migrate deeply into the PE matrix prior to dissociating into Cl and HO radicals and then, initiating a radical chain oxidation. The validity of the kinetic model derived from this scenario was successfully checked by comparing the numerical simulations with all the experimental data collected in this study. This model predicts the general trends of the oxidation kinetics and its dependence on the pH value, but also gives access to the transport properties of the chlorinated disinfectants and their radical species, and the rate constants of the radical attack

    PAX3-NCOA1 alveolar rhabdomyosarcoma of the tongue: A rare entity with challenging diagnosis and management.

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    AbstractAlveolar rhabdomyosarcoma (ARMS) is associated with PAX3/PAX7‐FOXO1 fusion, which confers specific clinic and biologic characteristics with inferior outcomes. A minority of tumors still histologically classified as "true" ARMS lack the canonical PAX‐FOXO1 fusion but have new molecular alterations. We present the first case of PAX3‐NCOA1 ARMS with clinical data and follow‐up in a two‐year‐old girl with ARMS of the tongue and nodal extension, treated with chemotherapy, hemi glossectomy, lymph node dissection, and brachytherapy to conserve oral function and limit long‐term sequelae. Given the rarity of such variant fusion in ARMS, international collaboration is required to evaluate its prognostic value

    Non-Hodgkin Lymphoma in Children and Adolescents: Progress Through Effective Collaboration, Current Knowledge, and Challenges Ahead

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    Non-Hodgkin lymphoma is the fourth most common malignancy in children, has an even higher incidence in adolescents, and is primarily represented by only a few histologic subtypes. Dramatic progress has been achieved, with survival rates exceeding 80%, in large part because of a better understanding of the biology of the different subtypes and national and international collaborations. Most patients with Burkitt lymphoma and diffuse large B-cell lymphoma are cured with short intensive pulse chemotherapy containing cyclophosphamide, cytarabine, and high-dose methotrexate. The benefit of the addition of rituximab has not been established except in the case of primary mediastinal B-cell lymphoma. Lymphoblastic lymphoma is treated with intensive, semi-continuous, longer leukemia-derived protocols. Relapses in B-cell and lymphoblastic lymphomas are rare and infrequently curable, even with intensive approaches. Event-free survival rates of approximately 75% have been achieved in anaplastic large-cell lymphomas with various regimens that generally include a short intensive B-like regimen. Immunity seems to play an important role in prognosis and needs further exploration to determine its therapeutic application. ALK inhibitor therapeutic approaches are currently under investigation. For all pediatric lymphomas, the intensity of induction/consolidation therapy correlates with acute toxicities, but because of low cumulative doses of anthracyclines and alkylating agents, minimal or no long-term toxicity is expected. Challenges that remain include defining the value of prognostic factors, such as early response on positron emission tomography/computed tomography and minimal disseminated and residual disease, using new biologic technologies to improve risk stratification, and developing innovative therapies, both in the first-line setting and for relapse

    Treatment at Relapse for Synovial Sarcoma of Children, Adolescents and Young Adults:From the State of Art to Future Clinical Perspectives

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    While the overall prognosis is generally quite satisfactory in children, adolescents and young adults with localised synovial sarcoma at first diagnosis, the outcome remains poor for patients after relapse. Conversely to the front-line standardised treatment options, patients with relapse generally have an individualised approach and to date, there is still a lack of consensus regarding standard treatment approaches. Studies on relapsed synovial sarcoma were able to identify some prognostic variables that influence post-relapse survival, in order to plan risk-adapted salvage protocols. Treatment proposals must consider previous first-line treatments, potential toxicities, and the possibility of achieving an adequate local treatment by new surgery and/or re-irradiation. Effective second-line drug therapies are urgently needed. Notably, experimental treatments such as adoptive engineered TCR-T cell immunotherapy seem promising in adults and are currently under validation also in paediatric patients.</p
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