40 research outputs found

    Origin of micro-scale heterogeneity in polymerisation of photo-activated resin composites

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    Photo-activated resin composites are widely used in industry and medicine. Despite extensive chemical characterisation, the micro-scale pattern of resin matrix reactive group conversion between filler particles is not fully understood. Using an advanced synchrotron-based wide-field IR imaging system and state-of-the-art Mie scattering corrections, we observe how the presence of monodispersed silica filler particles in a methacrylate based resin reduces local conversion and chemical bond strain in the polymer phase. Here we show that heterogeneity originates from a lower converted and reduced bond strain boundary layer encapsulating each particle, whilst at larger inter-particulate distances light attenuation and monomer mobility predominantly influence conversion. Increased conversion corresponds to greater bond strain, however, strain generation appears sensitive to differences in conversion rate and implies subtle distinctions in the final polymer structure. We expect these findings to inform current predictive models of mechanical behaviour in polymer-composite materials, particularly at the resin-filler interface

    The Compact Linear Collider (CLIC) - 2018 Summary Report

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    The Compact Linear Collider (CLIC) - 2018 Summary Report

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    The Compact Linear Collider (CLIC) is a TeV-scale high-luminosity linear e+ee^+e^- collider under development at CERN. Following the CLIC conceptual design published in 2012, this report provides an overview of the CLIC project, its current status, and future developments. It presents the CLIC physics potential and reports on design, technology, and implementation aspects of the accelerator and the detector. CLIC is foreseen to be built and operated in stages, at centre-of-mass energies of 380 GeV, 1.5 TeV and 3 TeV, respectively. CLIC uses a two-beam acceleration scheme, in which 12 GHz accelerating structures are powered via a high-current drive beam. For the first stage, an alternative with X-band klystron powering is also considered. CLIC accelerator optimisation, technical developments and system tests have resulted in an increased energy efficiency (power around 170 MW) for the 380 GeV stage, together with a reduced cost estimate at the level of 6 billion CHF. The detector concept has been refined using improved software tools. Significant progress has been made on detector technology developments for the tracking and calorimetry systems. A wide range of CLIC physics studies has been conducted, both through full detector simulations and parametric studies, together providing a broad overview of the CLIC physics potential. Each of the three energy stages adds cornerstones of the full CLIC physics programme, such as Higgs width and couplings, top-quark properties, Higgs self-coupling, direct searches, and many precision electroweak measurements. The interpretation of the combined results gives crucial and accurate insight into new physics, largely complementary to LHC and HL-LHC. The construction of the first CLIC energy stage could start by 2026. First beams would be available by 2035, marking the beginning of a broad CLIC physics programme spanning 25-30 years

    Orbital abscess: Visual loss following extraction of a tooth - Case report

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    Objective. It is the purpose of this article to alert the general practitioner to the severe consequences that may result from a tooth extraction, including the loss of vision, despite the use of antibiotics. Conclusions. Early and aggressive treatment is critical in obstructing the spread of infection toward the orbits, the eyes, and eventually the brain. © 2005 Mosby, Inc. All rights reserved

    Chordomas of the upper cervical spine: radiographic evaluation. Study of two cases and review of the literature

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    Chordomas are rare bony tumors, usually involving the skull base and sacrococcygeal spine, while least presented in cervical and thoracic spine. Chordomas of the cervical spine may cause variable neurological symptoms. Adult patients presenting with neck pain, paresthesias or limb paresis are further investigated. The history of progressive tetraparesis, however, implies a long-standing disease. Clinical presentation and imaging investigation of the cervical spine chordoma aims to alert the physicians for its early detection. Herein is reported the clinical presentation of two chordomas with progressive tetraparesis in two patients involving in both cases the third cervical vertebra. Plain radiographs, bone scintigraphy, CT and MR scanning were the imaging modalities depicting the mass, its prevertebral and intraspinal extension

    Ocular flutter as presenting manifestation of pediatric MOG antibody–associated demyelination: A case report

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    A 13-year-old girl presented with a 5-day history of oscillopsia. On examination, ocular flutter and mild cerebellar signs were found. Brain magnetic resonance imaging (MRI) revealed four periventricular and subcortical non-enhancing lesions. Cerebrospinal fluid (CSF) oligoclonal bands were negative. Neuroblastoma or other malignancies were not found. She responded well to a corticosteroid–intravenous immunoglobulin (IVIG) combination and remained symptom-free for 3 years until presenting again with isolated ocular flutter. Brain MRI at this time remained atypical for classic multiple sclerosis (MS) with a predominance of juxtacortical demyelinating lesions. CSF was positive for oligoclonal bands. Serum myelin oligodendrocyte glycoprotein (MOG) antibodies were present. Ocular flutter can be the presenting feature of MOG antibody–associated pediatric demyelination. © The Author(s), 2018

    Brucella spondylitis complicated by an infected abdominal aortic aneurysm and deep venous thrombosis: case report and review of the literature

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    Brucellosis is a common zoonosis, which still remains as a major health problem in certain parts of the world. Spondylodiscitis is the most frequent osteoarticular complication of brucellosis. Herein is reported an uncommon case of a middle-aged male treated for brucellosis who developed 2 years after the treatment brucellar spondylo-discitis complicated by a psoas muscle abscess, an infected abdominal aorta aneurysm and deep venous thrombosis of IVC, common iliac, external iliac and common femoral veins. CT and CT angiography were the imaging modalities depicting the findings. After an endovascular stent graft placement in abdominal aorta aneurysm, a CT guided drainage of retroperitoneal abscess revealed Brucella melitensis as the pathogen microorganism. Diagnosis of spondylodiscitis and contiguous psoas abscess is usually simple but aortic involvement is difficult to identify and can be easily overlooked. A high degree of suspicion is essential to reduce the delay for the treatment
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