229 research outputs found

    An Analysis of Surface Properties of Hetero-Epitaxially Grown SiC Surface on Si Substrate

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    The molecular beam epitaxy process can produce single crystal and smooth surface at atomic level as well as synthesizing the desired material by supplying the multiple materials on substrates. This paper deals with an application of the hetero-epitaxial process of silicon carbide (SiC) on silicon (Si) substrate, and aims to make clear the attainable surface roughness and its properties. It was found that the steep pits were formed during the carbonization process before the epitaxy and that they strongly affected the final roughness. The attainable roughness was 0.4nm rms. Finally, the applicability to toroidal mirror optics was discussed

    Local Unfolding of Cu, Zn Superoxide Dismutase Monomer Determines the Morphology of Fibrillar Aggregates

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    Aggregation of Cu, Zn Superoxide Dismutase (SOD1) is often found in Amyotrophic Lateral Sclerosis (ALS) patients. The fibrillar aggregates formed by wildtype and various disease-associated mutants have recently been found to have distinct cores and morphologies. Previous computational and experimental studies of wildtype SOD1 suggest that the apo-monomer, highly aggregation-prone, displays substantial local unfolding dynamics. The residual folded structure of locally unfolded apoSOD1 corresponds to peptide segments forming the aggregation core as identified by a combination of proteolysis and mass spectroscopy. Therefore, we hypothesize that the destabilization of apoSOD1 caused by various mutations leads to distinct local unfolding dynamics. The partially unfolded structure, exposing the hydrophobic core and backbone hydrogen bond donors and acceptors, is prone to aggregate. The peptide segments in the residual folded structures form the “building block” for aggregation, which in turn determines the morphology of the aggregates. To test this hypothesis, we apply a multiscale simulation approach to study the aggregation of three typical SOD1 variants: wildtype, G37R, and I149T. Each of these SOD1 variants has distinct peptide segments forming the core structure and features different aggregate morphologies. We perform atomistic molecular dynamics simulations to study the conformational dynamics of apoSOD1 monomer, and coarse-grained molecular dynamics simulations to study the aggregation of partially unfolded SOD1 monomers. Our computational studies of monomer local unfolding and the aggregation of different SOD1 variants are consistent with experiments, supporting the hypothesis of the formation of aggregation “building blocks” via apo-monomer local unfolding as the mechanism of SOD1 fibrillar aggregation

    A silent gigantic solitary fibrous tumor of the pleura: case report

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    Solitary fibrous tumor of the pleura is a rare mesenchymal tumor, representing less than 5% of all neoplasms associated with the pleura. A 57-year-old man had general malaise without chest symptoms for 1 month. A chest roentgenogram and computed tomography showed a giant mass in the left thorax. Although the tumor compressed the descending aorta and other mediastinal structures strongly, thereby shifting them to the right side, the patient had no symptoms except malaise. The tumor was successfully resected via two separate thoracotomies. The tumor was measured (20 cm × 19 cm × 15 cm) and weighed (2150 g). The tumor was histologically and immunohistochemically diagnosed as benign. Although SFT is benign, a long follow-up period is essential as even patients with complete resection are at risk of recurrence many years after surgery

    Infrequent Mutation of Lysophosphatidic Acid Receptor-1 Gene in Hamster Pancreatic Duct Adenocarcinomas and Established Cell Lines

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    To evaluate the involvement of lysophosphatidic acid receptor-1 (LPA1) gene alteration in pancreatic carcinogenesis, we investigated mutations in the LPA1 gene in hamster pancreatic duct adenocarcinomas (PDAs) and established cell lines. Female Syrian golden hamsters received 30 mg/kg of N-nitrosobis(2-oxopropyl)amine (BOP) followed by repeated exposure to an augmentation pressure regimen consisting of a choline-deficient diet combined with DL-ethionine and then L-methionine and a further administration of 20 mg/kg BOP. A total of 10 PDAs obtained 10 weeks after beginning the experiment and three cell lines established from subcutaneously transplantable PDAs in syngeneic hamsters were examined for mutations using reverse transcription-polymerase chain reaction-single strand conformation polymorphism (RT-PCR-SSCP) analysis. A mutation was detected in only one PDA (1/10, 10%) in the form of a GGA to GTA (Gly to Val) transversion at codon 355, and no mutations were detected in the three cell lines. These results suggest that the LPA1 gene mutation may play roles in a limited fraction of BOP-induced pancreatic duct carcinogenesis in hamsters

    Reduced reactive hyperemia of the brachial artery in diabetic patients assessed by repeated measurements : The FMD-J B study

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    Type 2 diabetes mellitus (T2DM) is a major cause of microvascular dysfunction. However, its effect on blood flow patterns during ischemic demand has not been adequately elucidated. In this study, we investigated the hypothesis that microvascular dysfunction in patients with T2DM manifests as brachial reactive hyperemia (BRH), defined as the ratio of peak blood flow velocities in a brachial artery before and after forearm cuff occlusion. The study enrolled 943 subjects (men, n = 152 [T2DM] and n = 371 [non-T2DM]; women, n = 107 [T2DM] and n = 313 [non-T2DM], respectively) with no history of cardiovascular disease. Semiautomatic measurements were obtained three times at 1.5-year intervals to confirm the reproducibility of factors involved in BRH for each sex. An age-adjusted mixed model demonstrated attenuated BRH in the presence of T2DM in both men (p = 0.022) and women (p = 0.031) throughout the study period. Post hoc analysis showed that the estimated BRH was significantly attenuated in patients with T2DM regardless of sex, except at baseline in women. In multivariate regression analysis, T2DM was a negative predictor of BRH at every measurement in men. For women, BRH was more strongly associated with alcohol consumption. Repeated measurements analysis revealed that T2DM was associated with attenuated postocclusion reactive hyperemia
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