1,070 research outputs found

    Dissimilar Electron Beam Welding of Nickel Base Alloy 625 and 9% Cr Steel

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    AbstractTo improve the thermal efficiency of fossil running power plants increasing the live steam temperature is essential. In power plant construction, 9-12% chromium martensitic steels are widely used but if steam temperatures rise above 625°C there is no way around nickel base alloys.The scope of this study was to ascertain the weldability of cast nickel base alloy 625 with cast martensitic 9% chromium steel COST CB2, using electron beam welding (EBW). Similar (A625/A625) and dissimilar joint welding experiments on 50mm thick plates were executed. Microstructure of welded joints was investigated and mechanical-technological tests were carried out.Results show that work pieces were completely welded and the microstructure of the seam shows no problems except some δ-ferrite grains near the fusion line on the CB2 side. The joints exhibit good mechanical properties in spite of the presence of a thin layer with very high hardness in the heat affected zone (HAZ) on the CB2 steel side. [1]

    Variation in the cortical area map of C57BL/6J and DBA/2J inbred mice predicts strain identity

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    BACKGROUND: Recent discoveries suggest that arealization of the mammalian cortical sheet develops in a manner consonant with principles established for embryonic patterning of the body. Signaling centers release morphogens that determine regional growth and tissue identity by regulating regional expression of transcription factors. Research on mouse cortex has identified several candidate morphogens that affect anteroposterior or mediolateral cortical regionalization as well as mitogenesis. Inbred strains of laboratory mice can be exploited to study cortical area map formation if there are significant phenotypic differences with which to correlate gene polymorphism or expression data. Here we describe differences in the cortical area map of two commonly used inbred strains of laboratory mice, C57BL/6J and DBA/2J. Complete cortical hemispheres from adult mice were dissected and stained for the cytochrome oxidase enzyme in order to measure histochemically defined cortical areas. RESULTS: C57BL/6J has the larger neocortex, relatively larger primary visual cortex (V1), but relatively smaller posterior medial barrel subfield of the primary somatosensory cortex (PMBSF). The sample of C57BL/6J and DBA/2J mice can be discriminated with 90% accuracy on the basis of these three size dimensions. CONCLUSION: C57BL/6J and DBA/2J have markedly different cortical area maps, suggesting that inbred strains harbor enough phenotypic variation to encourage a forward genetic approach to understanding cortical development, complementing other approaches

    Wire-based additive manufacturing using an electron beam as heat source

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    Complete removal of heart-compressing large mediastinal lipoma : a case report

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    An 83-year-old man presented with worsening of respiratory discomfort and underwent close examination, which revealed a large mediastinal lipoma measuring 15 × 10 cm. The patient showed heart failure symptoms due to heart compression by tumor. The tumor was completely removed safely and reliably by cutting the ascending aorta, main pulmonary artery and superior vena cava. Although preoperative examination could not determine whether the tumor was lipoma or liposarcoma, we selected an invasive surgical therapy because neither radiation therapy nor chemotherapy was considered effective for either type of tumor. We report here a very rare case of heart-compressing mediastinal tumor

    Fibromatosis of the Plantar Fascia: Diagnosis and Indications For Surgical Treatment

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    Plantar fibromatosis is a rare, benign lesion involving the plantar aponeurosis. Eleven patients (13 feet) underwent 24 operations, including local excision, wide excision, or complete plantar fasciectomy. Clinical results were evaluated retrospectively. There were no differences among the subgroups in postoperative complications. Two primary fasciectomies did not recur. Three of six revised fasciectomies, seven of nine wide excisions, and six of seven local excisions recurred. Our results indicate that recurrence of plantar fibromatosis after surgical resection can be reduced by aggressive initial surgical resection

    Disability in multiple sclerosis is related to thalamic connectivity and cortical network atrophy.

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    BACKGROUND: Thalamic atrophy is proposed to be a major predictor of disability progression in multiple sclerosis (MS), while thalamic function remains understudied. OBJECTIVES: To study how thalamic functional connectivity (FC) is related to disability and thalamic or cortical network atrophy in two large MS cohorts. METHODS: Structural and resting-state functional magnetic resonance imaging (fMRI) was obtained in 673 subjects from Amsterdam (MS: N = 332, healthy controls (HC): N = 96) and Graz (MS: N = 180, HC: N = 65) with comparable protocols, including disability measurements in MS (Expanded Disability Status Scale, EDSS). Atrophy was measured for the thalamus and seven well-recognized resting-state networks. Static and dynamic thalamic FC with these networks was correlated with disability. Significant correlates were included in a backward multivariate regression model. RESULTS: Disability was most strongly related (adjusted R2 = 0.57, p < 0.001) to higher age, a progressive phenotype, thalamic atrophy and increased static thalamic FC with the sensorimotor network (SMN). Static thalamus-SMN FC was significantly higher in patients with high disability (EDSS ⩾ 4) and related to network atrophy but not thalamic atrophy or lesion volumes. CONCLUSION: The severity of disability in MS was related to increased static thalamic FC with the SMN. Thalamic FC changes were only related to cortical network atrophy, but not to thalamic atrophy

    Pitfalls in the diagnosis of a tumefactive demyelinating lesion: A case report

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    <p>Abstract</p> <p>Introduction</p> <p>In rare instances, demyelinating disorders manifest as tumefactive lesions that simulate brain tumors. We report a patient with a space-occupying lesion in the parietal lobe, which presented a serious diagnostic dilemma, between a rare tumefactive demyelinating disease, such as Balo concentric sclerosis and a glioma. This case report highlights important diagnostic clues in the differential diagnosis of Balo concentric sclerosis.</p> <p>Case presentation</p> <p>A 20-year-old Caucasian woman with acute onset of left-sided weakness and numbness was admitted to hospital with neurologic signs of left-sided hemiparesis and hypoesthesia. Brain magnetic resonance imaging showed a mass lesion of abnormal signal intensity with concentric enhancing rings in the right parietal lobe, without perifocal edema. The characteristic concentric pattern detected on the magnetic resonance images was highly suggestive of Balo disease, and corticosteroids were administered. Evoked potentials, cerebrospinal fluid analysis, and magnetic spectroscopy findings were not specific, and glioma was also included in the differential diagnosis. A stereotactic biopsy was not diagnostic.</p> <p>After one month the patient showed moderate clinical improvement, and during 12 months follow-up, no further relapses occurred. In the follow-up magnetic resonance imaging, the concentric pattern had completely disappeared, and only a low-signal, gliotic lesion remained.</p> <p>Conclusion</p> <p>We hope this case presentation will advance our understanding of clinical and radiologic appearance of Balo concentric sclerosis, which is a rare demyelinating disease. Although this is a specific entity, it has a broader clinical impact across medicine, because it must be differentiated from other space-occupying lesions in the central nervous system.</p

    Primary intra-abdominal malignant fibrous histiocytoma presenting as pyrexia of unknown origin – report of a case with review of literature

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    Primary intra-abdominal malignant mesenchymal tumours are very rare and there are not many cases of visceral malignant fibrous histiocytoma in the English literature. We report a new case of abdominal malignant fibrous histiocytoma presenting as abdominal pain and pyrexia of unknown origin in a 54 year old female followed by a brief review of literature. Presentation with pyrexia of unknown origin is extremely rare in this condition
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