98 research outputs found

    Antarctic primitive achondrites Yamato-74025, -75300, and -75305:Their mineralogy, thermal history and the relevance to winonaite

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    Three Antarctic primitive achondrites, Yamato (Y)-74025,-75300,and -75305 were mineralogically and chemically studied. They consist of anhedral to subhedral silicate and opaque minerals. The major constituent minerals are typical of equilibrated ordinary chondrites. However, they do not have any relic of chondrule, and the presence of various accessory minerals, such as K-feldspar, schreibersite, daubreelite, phosphate, Nb-bearing rutile, and magnesiochromite, characterizes these meteorites. Y-75305 has a composite grain containing Cu, Mn, and S, probably consisting of alabandite, an unknown Mn-bearing Cu-sulfide, and digenite. Y-74025 has a REE pattern typical of chondrite. Siderophile elements in Y-74025 are depleted relative to Cl chondrites, which is consistent with poor abundance of Fe-Ni metal in Y-74025. Holocrystalline texture, homogeneous mineral compositions, and high equilibration temperatures for pyroxenes, suggest that these primitive achondrites experienced high-temperature metamorphism. Mineralogical and chemical characteristics suggest that they resemble Winona-like meteorites (winonaites). The compositions of pyroxene and olivine, and accessory minerals suggest that winonaites formed under an intermediate redox condition between E-chondrites and Acapulco-like primitive achondrites. The abundance of troilite and Fe-Ni metal varies widely. The metal-sulfide fractions of winonaites probably melted and fractionated, although silicate fractions of winonaites do not have any evidence for melting

    Experimental Studies on an Embedded Structure-Soil Interaction

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    This paper describes the results of experimental studies performed the evaluation of the embedment effects on the dynamic characteristics of the structure and the correlation anlayses between the test results and the calculated results. The vibration tests of large scale models constructed on actual soil are carried out with the purpose of obtaining the basic data for verification study on analysis codes. In the correlation analyses, the methods used here are the sway-rocking model and the axisymmetric finite element method. These methods are confirmed to be applicable to analyse the response or the embedded structures

    Negotiating uneven terrain by a simple teleoperated tracked vehicle with internally movable center of gravity

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    We propose a mechanical design for a simple teleoperated unmanned ground vehicle (UGV) to negotiate uneven terrain. UGVs are typically classified into legged, legged-wheeled, wheeled, and tanked forms. Legged vehicles can significantly shift their center of gravity (COG) by positioning their multi-articulated legs at appropriate trajectories, stepping over a high obstacle. To realize a COG movable mechanism with a small number of joints, a number of UGVs have been developed that can shift their COG by moving a mass at a high position above the body. However, these tend to pose a risk of overturning, and the mass must be moved quite far to climb a high step. To address these issues, we design a novel COG shift mechanism, in which the COG can be shifted forward and backward inside the body by moving most of its internal devices. Since this movable mass includes DC motors for driving both tracks, we can extend the range of the COG movement. We demonstrate that a conventional tracked vehicle prototype can traverse a step and a gap between two steps, as well as climb stairs and a steep slope, with a human operating the vehicle movement and the movable mass position

    Rover wheel assistive grouser shape effects on traction force in flat soft terrain

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    This paper presents the study of different grouser shapes on the performance of the assistive grouser wheel travelling on a flat surface loose soil terrain. This work is an extension from our previous work exploring the rover wheel assistive grouser angle of attack effects on traction force in soft terrain. Therefore, a new experiment involving the different grouser shapes on the assistive grouser wheel must be conducted to comprehend the interactions between the grouser and loose soil. From observation, the bulldozing effect of the assistive grouser is also influenced by the grouser shapes. Further understanding of the soil flow also effect of the grouser shape design in general. Hence, we have developed 4 different grouser shapes to be attached to the single wheel rover testbed to evaluate the effects of the shape to the performance of the assistive grouser wheel on a 0-degree slope loose soil surface. The grouser shapes consisted of Inverse Parallel, C-Shape, Inverse C-Shape and Inverse Chevron Shape. The average total traction force and current consumption was examined. It was observed during the grouser entering the sand surface, the sand piled up onto the grouser surface effecting the value of average total traction force. This was caused by surface area of the grouser. The more surface area of the assistive grouser, the more traction force generated to push the wheel forward. Based on the experimental results, it was concluded that Inverse Parallel is the optimal grouser design for use as assistive grouser in wheeled rover on soft sand, as it has the lowest surface area and the lowest average total traction force. However, Inverse Chevron generated the least current consumption by the half-wheel rover. These results indicate that the traction force of the assistive grouser is not affected by shape, but the width and depth of the assistive grouser

    Interstitial pneumonia associated with MPO-ANCA: Clinicopathological features of nine patients

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    SummaryMyeloperoxidase anti-neutrophil cytoplasmic autoantibody (MPO-ANCA) is a well known marker for small vessel vasculitis. Recent reports have demonstrated that interstitial pneumonia (IP) may rarely be associated with serum MPO-ANCA. Yet, little is known about the histological features.We reviewed surgical lung biopsy from nine patients with IP of uncertain etiology with serum MPO-ANCA.There was a male predominance (6:3) with a median age of 62.1. Histologically, eight patients presented with a usual interstitial pneumonia (UIP) pattern of pulmonary fibrosis, frequently accompanied by areas of nonspecific interstitial pneumonia (NSIP) pattern. One patient showed diffuse alveolar damage (DAD), and two patients showed mixture of UIP and DAD reflecting acute exacerbation of UIP. Microscopic honeycomb cysts were common, but fibroblastic foci were inconspicuous. The most frequent additional findings were small airway disease (9/9), and lymphoid follicles (7/9). Neither capillaritis nor vasculitis was seen in any of our cases. Three patients had microscopic hematuria, but none progressed to microscopic polyangiitis during the follow up. Mortality rate was 44% (median follow up 39.1 months).IP associated with MPO-ANCA showed characteristic histology dominated by UIP pattern. Vasculitis was not identified in our cohort, but small airways disease and lymphoid follicles were present in most cases. IP associated with MPO-ANCA may be a histologically distinctive disease from idiopathic pulmonary fibrosis. Mortality was relatively high and life threatening acute exacerbation may occur

    Pace running of a quadruped robot driven by pneumatic muscle actuators : An experimental study

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    Our goal is to design a neuromorphic locomotion controller for a prospective bioinspired quadruped robot driven by artificial muscle actuators. In this paper, we focus on achieving a running gait called a pace, in which the ipsilateral pairs of legs move in phase, while the two pairs together move out of phase, by a quadruped robot with realistic legs driven by pneumatic muscle actuators. The robot is controlled by weakly coupled two-level central pattern generators to generate a pace gait with leg loading feedback. Each leg is moved through four sequential phases like an animal, i.e., touch-down, stance, lift-off, and swing phases. We find that leg loading feedback to the central pattern generator can contribute to stabilizing pace running with an appropriate cycle autonomously determined by synchronizing each leg’s oscillation with the roll body oscillation without a human specifying the cycle. The experimental results conclude that our proposed neuromorphic controller is beneficial for achieving pace running by a muscle-driven quadruped robot

    Influenza H1N1 virus-associated pneumonia often resembles rapidly progressive interstitial lung disease seen in collagen vascular diseases and COVID-19 pneumonia; CT-pathologic correlation in 24 patients

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    To describe computed tomography (CT) findings of influenza H1N1 virus-associated pneumonia (IH1N1VAP), and to correlate CT findings to pathological ones. The study included 24 patients with IH1N1VAP. Two observers independently evaluated the presence, distribution, and extent of CT findings. CT features were divided into either classical form (C-form) or non-classical form (NC-form). C-form included: A.) broncho-bronchiolitis and bronchopneumonia type, whereas NC-forms included: B.) diffuse peribronchovascular type, simulating subacute rheumatoid arthritis-associated (RA) interstitial lung disease (ILD) and C.) lower peripheral and/or peribronchovascular type, resembling dermatomyositis-associated ILD and COVID-19 pneumonia. In 10 cases with IH1N1VAP where lung biopsy was performed, CT and pathology findings were correlated. The most common CT findings were ground-glass opacities (24/24, 100 %) and airspace consolidation (23/24, 96 %). C-form was found in 11 (46 %) patients while NC-form in 13 (54 %). Types A, B, and C were seen in 11(46 %), 4 (17 %), and 9 (38 %) patients, respectively. The lung biopsy revealed organizing pneumonia in all patients and 6 patients (60 %) showed incorporated type organizing pneumonia that was common histological findings of rapidly progressive ILD. In almost half of patients of IH1N1VAP, CT images show NC-form pneumonia pattern resembling either acute or subacute RA or dermatomyositis-associated ILD and COVID-19 pneumonia

    Recognition of Connective Tissue Disease-Related Interstitial Pneumonia Based on Histological Score—A Validation Study of an Online Diagnostic Decision Support Tool

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    Objectives: to evaluate the number of cases of idiopathic pulmonary fibrosis (IPF) that included histological features of connective tissue disease (CTD) and to check whether they demonstrated the clinical features of CTD, using a previously reported CTD-interstitial pneumonia (IP) index that histologically differentiates CTD-associated and idiopathic IP. Methods: patients diagnosed with IPF following video-assisted thoracoscopic biopsy through multidisciplinary team diagnosis between 2014 and 2017 were selected. Pathological observation was made by four pathologists who scored eight observational items needed for the CTD-IP index. Cases determined as CTD, by the CTD-IP index, were extracted, and their clinical features were compared. Results: a total of 94 cases of IPF were identified, of which 20 were classified into the CTD group using the CTD-IP index with reasonable interobserver agreement (k = 0.76). Cases pathologically classified into the CTD group were significantly associated with female sex, non-smoking history, autoantibody positivity, and CTD symptoms (p = 0.01, 0.03, 0.01, and 0.04, respectively). Conclusions: patients with IPF with pathological findings of CTD showed clinical characteristics similar to those of patients with CTD

    Histologic factors associated with nintedanib efficacy in patients with idiopathic pulmonary fibrosis

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    Background Histopathologic factors predictive of nintedanib efficacy in idiopathic pulmonary fibrosis have not been studied. We aimed to describe the characteristics, focusing on histopathology, of idiopathic pulmonary fibrosis patients who did and did not respond to nintedanib. Methods This study retrospectively examined the clinicoradiopathologic features of 40 consecutive patients with surgical lung biopsy-confirmed idiopathic pulmonary fibrosis treated with nintedanib. Additionally, we compared the histopathologic scoring of 21 microscopic features between patients with functional or radiological progression and those with non-progression during 12 months of treatment. Results The histopathologic evaluation showed edematous changes in the interlobular septum as the only histologic finding observed more frequently in patients with both functional and radiological progression than in those without (58% vs. 14%, P = 0.007 and 50% vs. 0%, P = 0.003, respectively). Regarding per-year change, patients with edematous changes in the interlobular septum showed greater progression in median changes in spared area (-12%, interquartile range: [-25%-5%], vs. -3% [-7%-0%], P = 0.004) and reticular shadow (7% [3%-13%], vs. 0% [0%-5%], P = 0.041) on computed tomography. Functional and radiological progression-free survival were shorter in patients with edematous changes in the interlobular septum than in those without (6.6 months, 95% confidence interval: [5.9-25.3], vs. event <50%, [12.1-Not available], P = 0.0009, and 6.1 months, [5.2-6.6] vs. 14.5 months [7.8-not available], P<0.0001). Conclusions Edematous changes in the interlobular septum may indicate poor nintedanib efficacy in idiopathic pulmonary fibrosis. Further studies are needed to validate these findings and address the mechanism behind ECIS

    Preparation of Mesoporous and/or Macroporous SnO2-Based Powders and Their Gas-Sensing Properties as Thick Film Sensors

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    Mesoporous and/or macroporous SnO2-based powders have been prepared and their gas-sensing properties as thick film sensors towards H2 and NO2 have been investigated. The mesopores and macropores of various SnO2-based powders were controlled by self-assembly of sodium bis(2-ethylhexyl)sulfosuccinate and polymethyl-methacrylate (PMMA) microspheres (ca. 800 nm in diameter), respectively. The introduction of mesopores and macropores into SnO2-based sensors increased their sensor resistance in air significantly. The additions of SiO2 and Sb2O5 into mesoporous and/or macroporous SnO2 were found to improve the sensing properties of the sensors. The addition of SiO2 into mesoporous and/or macroporous SnO2 was found to increase the sensor resistance in air, whereas doping of Sb2O5 into mesoporous and/or macroporous SnO2 was found to markedly reduce the sensor resistance in air, and to increase the response to 1,000 ppm H2 as well as 1 ppm NO2 in air. Among all the sensors tested, meso-macroporous SnO2 added with 1 wt% SiO2 and 5 wt% Sb2O5, which were prepared with the above two templates simultaneously, exhibited the largest H2 and NO2 responses
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