185 research outputs found

    Space Dust Impacts Detector Development for the Evaluation of Ejecta

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    AbstractThis paper aims at a) introducing the space dust impacts detector developed at Kyushu Institute of Technology (KIT), b) presenting the detector utility for the evaluation of ejecta, and c) raising awareness of the space community regarding the risk represented by orbital debris. The space dust impacts detector introduced into this paper belongs to the in-situ detection systems and has for purposes to be a) light, 30g, b) low cost, about EUR200, c) low power consuming, 0.01W, d) easily adaptable on-board of spacecraft, and e) able to detect impacts of debris with a diameter ranging from 100μm to 600μm. The detector is mounted on the nano-satellite, Horyu-II, developed at KIT and launched on May 18, 2012. The data received will be very helpful to identify the detector's strengths and weaknesses to improve it and create a second version that will aim at evaluating ejecta fragments produced during hypervelocity impact testing. An accurate evaluation of ejecta is critical for orbital debris risk assessment and mitigation. If all space activities were stopped, debris will still be created by chain reaction. The number of debris could then become so large, that the access to certain LEOs will be quasi-impossible, which will jeopardize the space exploration as well as scientific, educational, and security missions that benefit to all mankind. Debris is therefore a serious issue that should be taken into consideration at every step of the development of a small or large spacecraft

    Hepatitis B Virus e Antigen Physically Associates With Receptor-Interacting Serine/Threonine Protein Kinase 2 and Regulates IL-6 Gene Expression

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    We previously reported that hepatitis B virus (HBV) e antigen (HBeAg) inhibits production of interleukin 6 by suppressing NF-κB activation. NF-κB is known to be activated through receptor-interacting serine/threonine protein kinase 2 (RIPK2), and we examined the mechanisms of interleukin 6 regulation by HBeAg. HBeAg inhibits RIPK2 expression and interacts with RIPK2, which may represent 2 mechanisms through which HBeAg blocks nucleotide-binding oligomerization domain-containing protein 1 ligand-induced NF-κB activation in HepG2 cells. Our findings identified novel molecular mechanisms whereby HBeAg modulates intracellular signaling pathways by targeting RIPK2, supporting the concept that HBeAg could impair both innate and adaptive immune responses to promote chronic HBV infectio

    Factors Associated with Inadequate Tissue Yield in EUS-FNA for Gastric SMT

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    Aims. Our aim was to identify the factors that made the specimens inadequate and nondiagnostic in endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) biopsy of suspected submucosal tumors (SMTs). Methods. From August 2001 to October 2009, 47 consecutive patients with subepithelial hypoechoic tumors originating in the fourth sonographic layer of the gastric wall suspected as GIST by standard EUS in Chiba University hospital underwent EUS-FNA for histologic diagnosis. We evaluated patient age, sex, location of lesion, size, pattern of growth in a stomach, and pattern of echography retrospectively. We defined a case of gaining no material or an insufficient material for immunohistological diagnosis as nondiagnostic. Results. The diagnostic yield of EUS-FNA for the diagnosis of gastric SMTs was 74.5%. Multivariate logistic regression analysis identified that age of under 60 years (compared with patients older than 60 years: odds ratio [OR] = 11.91, 95% confidence interval [CI] = 1.761–80.48) and location of SMT at lower third area (compared with upper or middle third area: OR = 10.62, 95% CI = 1.290–87.42) were the predictive factors for inadequate tissue yield in EUS-FNA. Conclusions. The factors associated with inadequate tissue yield in EUS-FNA were younger age and the location of lesion at lower third area in stomach

    Space Dust Impacts Detector Development for the Evaluation of Ejecta

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    This paper aims at a) introducing the space dust impacts detector developed at Kyushu Institute of Technology (KIT), b) presenting the detector utility for the evaluation of ejecta, and c) raising awareness of the space community regarding the risk represented by orbital debris. The space dust impacts detector introduced into this paper belongs to the in-situ detection systems and has for purposes to be a) light, 30 g, b) low cost, about EUR200, c) low power consuming, 0.01W, d) easily adaptable on-board of spacecraft, and e) able to detect impacts of debris with a diameter ranging from 100 μm to 600 μm. The detector is mounted on the nano-satellite, Horyu-II, developed at KIT and launched on May 18, 2012. The data received will be very helpful to identify the detector\u27s strengths and weaknesses to improve it and create a second version that will aim at evaluating ejecta fragments produced during hypervelocity impact testing. An accurate evaluation of ejecta is critical for orbital debris risk assessment and mitigation. If all space activities were stopped, debris will still be created by chain reaction. The number of debris could then become so large, that the access to certain LEOs will be quasi-impossible, which will jeopardize the space exploration as well as scientific, educational, and security missions that benefit to all mankind. Debris is therefore a serious issue that should be taken into consideration at every step of the development of a small or large spacecraft.2012 Hypervelocity Impact Symposium (HVIS 2012), September 16-20, 2012, Baltimore, Marylan

    Hepatitis C Virus Nonstructural 5A Protein Inhibits Lipopolysaccharide-Mediated Apoptosis of Hepatocytes by Decreasing Expression of Toll-Like Receptor 4

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    Background. Hepatitis C virus (HCV) nonstructural protein 5A (NS5A) has been shown to modulate multiple cellular processes, including apoptosis. The aim of this study was to assess the effects of HCV NS5A on apoptosis induced by Toll-like receptor (TLR) 4 ligand, lipopolysaccharide (LPS). Methods. Apoptotic responses to TLR4 ligands and the expression of molecules involved in TLR signaling pathways in human hepatocytes were examined with or without expression of HCV NS5A. Results. HCV NS5A protected HepG2 hepatocytes against LPS-induced apoptosis, an effect linked to reduced TLR4 expression. A similar downregulation of TLR4 expression was observed in Huh-7-expressing genotype 1b and 2a. In agreement with these findings, NS5A inhibited the expression of numerous genes encoding for molecules involved in TLR4 signaling, such as CD14, MD-2, myeloid differentiation primary response gene 88, interferon regulatory factor 3, and nuclear factor-κB2. Consistent with a conferred prosurvival advantage, NS5A diminished the poly(adenosine diphosphate-ribose) polymerase cleavage and the activation of caspases 3, 7, 8, and 9 and increased the expression of anti-apoptotic molecules Bcl-2 and c-FLIP. Conclusions. HCV NS5A downregulates TLR4 signaling and LPS-induced apoptotic pathways in human hepatocytes, suggesting that disruption of TLR4-mediated apoptosis may play a role in the pathogenesis of HCV infectio

    Feasibility of Standardized Ejecta Evaluation for Spacecraft Surface Materials

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    Although a large spacecraft such as the International Space Station and other artificial satellites are thriving in the space environment due to the remarkable progress in the space development sector, their collisions with space debris are a growing concern. To examine the impact proof performance of spacecraft to space debris, hypervelocity impact experiments using a two-stage light gas gun and so on are necessary. However, space debris impact experiments are conducted in different manners dependent on the countries and the facilities. Therefore direct comparisons of the experimental results among different facilities are often difficult from the same viewpoint. In this study, the authors aim at assessment of international standardization of the hypervelocity impact experiments procedure. Projectiles with a diameter of 1 mm were used to simulate space debris impacting a target at 5 km/s. Copper witness plates were used to catch the secondary debris, namely ejecta, generated during the experiments. The size distributions of diameter of craters made by ejecta were measured on the witness plates, and they are compared one another among a solar array coupon, CFRP honeycomb and Aluminum honeycomb.2012 Hypervelocity Impact Symposium (HVIS 2012), September 16-20, 2012, Baltimore, Marylan

    Hepatic STAT1-Nuclear Translocation and Interleukin 28B Polymorphisms Predict Treatment Outcomes in Hepatitis C Virus Genotype 1-Infected Patients

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    We investigated associations between signal transducer and activator of transcription (STAT) 1 in pretreated liver tissues, interleukin (IL) 28B polymorphism and treatment response in hepatitis C virus (HCV)-infected patients treated with peginterferon and ribavirin.We performed immunostaining analysis of STAT1 in liver tissues and determined IL28B polymorphism at rs8099917. We then compared the results with treatment outcomes in HCV genotype 1 patients with high viral load who were receiving peginterferon plus ribavirin. In univariate analysis, younger age, white blood cell counts, virological responder, early virological responder (EVR), mild activity (A1) of liver inflammation grading, and lower STAT1 nuclear-stain of hepatocytes in zone 1, zone 2 and total zones of liver were associated with sustained virological responder (SVR). Multivariate analysis showed that EVR, age and hepatic STAT1 nuclear-stain in zone 2 of liver were independent predictors of SVR. It was also revealed that IL28B and STAT1-nuclear translocation in hepatocytes are independent predictors of response to treatment with peginterferon and ribavirin in chronic hepatitis C patients.Concomitant assessment of lower STAT1 nuclear-stain of hepatocytes and IL28B polymorphism is useful for prediction of SVR in HCV genotype 1 patients

    Assessment of Macrovascular Invasion in Advanced Hepatocellular Carcinoma: Clinical Implications and Treatment Outcomes with Systemic Therapy

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    Introduction: Macrovascular invasion (MVI) is a strong prognostic factor for advanced hepatocellular carcinoma (HCC). The current criteria for radiological assessment are unclear in evaluating the impact of MVI on systemic therapy. In this study, we standardized the assessment of MVI and validated its clinical relevance. Methods: Clinical data were collected from patients with advanced HCC and MVI who received first-line systemic therapy at four medical centers in Japan. First, we used macrovascular invasion progression disease (MVI-PD) to track MVI progression, and Response Evaluation Criteria in Solid Tumours version 1.1 progression disease (RECIST v1.1-PD) to evaluate tumor enlargement other than MVI and the appearance of new lesions. Next, we assessed the prognostic value of MVI-PD and RECIST v1.1-PD. Results: Of the 207 advanced HCC patients with MVI, 189 received appropriate imaging evaluation. 40 (21.2%) patients had MVI-PD and RECIST v1.1-PD, 51 (27.0%) had prior MVI-PD, and 61 (32.3%) had prior RECIST v1.1-PD. In a landmark analysis, the prognosis of 163 patients who survived more than three months was analyzed based on the assessment of imaging response during the first three months. The median overall survival (OS) was 5.4 months in those who had MVI-PD and RECIST v1.1-PD, 7.4 months in those who had RECIST v1.1-PD only, 7.2 months in those who had MVI-PD only, and 19.7 months in patients who had neither (p<0.001). The correlation coefficients between progression-free survival and OS in patients with appropriate imaging assessments were similar for MVI-PD (0.515) and RECIST v1.1-PD (0.498). Conclusion: Our findings demonstrate the link between MVI progression and poor OS in systemic therapy for advanced HCC, emphasizing the importance of an accurate method for assessing MVI progression
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