152 research outputs found

    In-situ observation of twinning and detwinning in AZ31 alloy

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    Twinning and detwinning behavior of a commercial AZ31 magnesium alloy during cyclic compression–tension deformation with a total strain amplitude of 4% (±2%) was evaluated using the complementary techniques of in-situ neutron diffraction, identical area electron backscatter diffraction, and transmission electron microscopy. In-situ neutron diffraction demonstrates that the compressive deformation was dominated by twin nucleation, twin growth, and basal slip, while detwinning dominated the unloading of compressive stresses and subsequent tension stage. With increasing number of cycles from one to eight: the volume fraction of twins at -2% strain gradually increased from 26.3% to 43.5%; the residual twins were present after 2% tension stage and their volume fraction increased from zero to 3.7% as well as a significant increase in their number; and the twinning spread from coarse grains to fine grains involving more grains for twinning. The increase in volume fraction and number of residual twins led to a transition from twin nucleation to twin growth, resulting in a decrease in yield strength of compression deformation with increasing cycles. A large number of -component dislocations observed in twins and the detwinned regions were attributed to the dislocation transmutation during the twinning and detwinning. The accumulation of barriers including twin boundaries and various types of dislocations enhanced the interactions of migrating twin boundary with these barriers during twinning and detwinning, which is considered to be the origin for increasing the work hardening rate in cyclic deformation of the AZ31 alloy

    Male’s influence on the primary sex ratio bias in Ryukyu drywood termite

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    Selfish genetic elements (SGEs) increase their transmission efficiency relative to the rest of the individual genome, which is often deleterious to individual fitness. Theoretical studies have suggested that intragenomic conflict over the sex ratio distortion between SGEs and the rest of the genome should lead to the evolution of sex-determining systems. However, in insects, there are relatively few studies other than those on Dipterans, which makes it difficult to understand the role of SGEs in the evolution of insect sex determination. This is partially due to the difficulties in observing SGEs under field conditions. The effect of SGEs is often masked by the counter-evolution of the resistance genes. Interpopulation cross-breeding experiments are effective to detect the SGEs and their resistance genes. If these populations have different SGEs and resistance genes, cross-breeding experiments reveal their existence by collapsing the evolutionary antagonistic state. The Ryukyu drywood termites Neotermes sugioi, distributed in the Ryukyu Islands, show male-biased sex ratios in pseudergates, nymphs, alates and soldiers both in Okinawa and Ishigaki Islands, but different degrees of bias have been reported between the islands. Male-specific microsatellite alleles have been reported in this species, which allowed us to identify the sex of the eggs and young larvae. In this study, we used the microsatellite locus with male-specific alleles to investigate the primary sex ratio of field colonies on Okinawa and Ishigaki islands and the sex ratio of offspring obtained through cross-breeding experiments between the islands. The primary sex ratios of field colonies were male-biased in Okinawa but not in Ishigaki. Cross-breeding experiments showed that Okinawa males tend to have a male-biased sex ratio in their offspring, but Ishigaki males do not. This result is consistent with the hypothesis that the male bias in this species is caused by SGEs, even though termites are phylogenetically distant from Diptera. Accumulation of knowledge on genetic conflicts in a wide range of taxa might be an important step toward elucidating the mechanisms of diversification of sex determination systems in insects

    Dynamic Behavior of Pipe Inspection Robot Driven by Fluid Force

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    This paper discusses the dynamic behavior of a pipe inspection robot driven by fluid force. The robot is composed of an inspection part, insertion roller, floats and cables to connect the floats. The robot receives not only drag force but also lift force through each float implemented in every link unit. Through simulation, we found that according to the shape of the pipe, there exists an optimum fluid velocity which provides the inspection position at the center of the pipe. Such optimum velocity is a function of mechanical impedance existing in the robot itself and the radius of curvature. We show a method which keeps the inspection part parallel to the pipe axis irrespective of the position of the center of the radius of pipe. We also consider the dynamic behavior of the inspection part under various parameters, such as the radius of pipe curvature, mechanical impedance of the robot, and the fluid flow rate

    Advanced Laser Diagnostics for Electron Density Measurements

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    This paper describes innovative laser diagnostics under development at the National Institute for Fusion Science, aiming for the establishment of reliable density measurement techniques in the next step magneticallyconfined fusion devices. There are two approaches, interferometry and polarimetry. A new type of two color laser (47.6/57.2-μm CH3OD) interferometer has been developed and its original function, vibration subtraction,was confirmed in a test stand. The line integrated density measurement at Compact Helical System by using the polarimeter based on Cotton-Mouton effect was demonstrated by the use of a 337-μm HCN laser source

    An informationally structured room for robotic assistance

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    The application of assistive technologies for elderly people is one of the most promising and interesting scenarios for intelligent technologies in the present and near future. Moreover, the improvement of the quality of life for the elderly is one of the first priorities in modern countries and societies. In this work, we present an informationally structured room that is aimed at supporting the daily life activities of elderly people. This room integrates different sensor modalities in a natural and non-invasive way inside the environment. The information gathered by the sensors is processed and sent to a centralized management system, which makes it available to a service robot assisting the people. One important restriction of our intelligent room is reducing as much as possible any interference with daily activities. Finally, this paper presents several experiments and situations using our intelligent environment in cooperation with our service robot. © 2015 by the authors

    Biologic markers in prostatic intraepithelial neoplasia: immunohistochemical and cytogenetic analyses

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    Objective:We evaluated the biological properties of High-grade prostatic intraepithelial neoplasia (PIN) by immunohistochemistry and fluorescence in situ hybridization (FISH) analysis in relation to normal tissue and carcinoma lesions. Materials and Methods:Immunohistochemical staining and FISH were performed on23formalin-fixed radical prostatectomy specimens taken from patients with PIN. Assays were performed using MIB-1, chromogranin A (CGA) and an anti-androgen receptor antibody (AR). A centromere probe for chromosome8was used to test for aneuploidy. Results:The MIB-1index of cancerous specimens (16.2±10.5%) was significantly higher than that of benign (1.9±1.6%, p<0.0001) or PIN (4.0±4.5%, p<0.0001) specimens. The percentage of CGA positive cells was significantly lower in normal tissue (1.2±1.8%) than in PIN (3.5±2.9%, p=0.012) or carcinoma (5.4±4.9%, p=0.005) lesions. Positive staining for AR was consistently observed in the nuclei of both benign and malignant epithelial cells, but positive cytoplasmic staining was also seen in PIN epithelial cells. No significant difference in FISH detected anomalies were found between PIN and carcinoma specimens. Conclusions:Our studies concerning proliferative activity, NE differentiation and chromosomal anomalies of prostatic specimens support the hypothesis that PIN is a biologically intermediate stage in the pathogenesis of prostatic carcinoma. The cellular distribution of AR was altered in PIN cells, but the role of AR in PIN is not yet clear

    Expression of interleukin-33 is correlated with poor prognosis of patients with squamous cell carcinoma of the tongue

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    Objective: The aim of this study was to clarify the role of IL-33 in tumor progression. Methods: Surgical specimens from 81 patients with squamous cell carcinoma of the tongue were studied using immunohistochemistry. Primary tumor sections were analyzed for IL-33 and ST2 expression. To examine the influence of IL-33 on the microenvironment of the tumor, we determined the mast cell density (MCD) and microvessel density of the stroma. Results: Patients with high IL-33 expression had a significantly worse prognosis (p = 0.004). IL-33 expression was significantly elevated in patients with local and nodal recurrence (p = 0.014 and p = 0.019). ST2 expression was also associated with a worse prognosis (p = 0.024) and was significantly elevated in patients with nodal recurrence (p = 0.004). MCD was associated with worse prognosis (p = 0.038) and correlated significantly with IL-33 expression (r = 0.626, p < 0.001). Micovessels in the stroma were significantly increased in the high IL-33 group (p < 0.001). Conclusion: These data suggest that the IL-33/ST2 axis contributes to tumor aggressiveness and affects the tumor microenvironment. Immunohistochemical evaluation of IL-33 and ST2 is useful for identifying patients at a high risk for poor prognosis. © 2014 Elsevier Ireland Ltd. All rights reserved

    Feasibility study of immediate pharyngeal cooling initiation in cardiac arrest patients after arrival at the emergency room

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    AIM: Cooling the pharynx and upper oesophagus would be more advantageous for rapid induction of therapeutic hypothermia since the carotid arteries run in their vicinity. The aim of this study was to determine the effects of pharyngeal cooling on brain temperature and the safety and feasibility for patients under resuscitation. METHODS: Witnessed non-traumatic cardiac arrest patients (n=108) were randomized to receive standard care with (n=53) or without pharyngeal cooling (n=55). In the emergency room, pharyngeal cooling was initiated before or shortly after return of spontaneous circulation by perfusing physiological saline (5 °C) into a pharyngeal cuff for 120 min. RESULTS: There was a significant decrease in tympanic temperature at 40 min after arrival (P=0.02) with a maximum difference between the groups at 120 min (32.9 ± 1.2°C, pharyngeal cooling group vs. 34.1 ± 1.3°C, control group; P<0.001). The return of spontaneous circulation (70% vs. 65%, P=0.63) and rearrest (38% vs. 47%, P=0.45) rates were not significantly different based on the initiation of pharyngeal cooling. No post-treatment mechanical or cold-related injury was observed on the pharyngeal epithelium by macroscopic observation. The thrombocytopaenia incidence was lower in the pharyngeal cooling group (P=0.001) during the 3-day period after arrival. The cumulative survival rate at 1 month was not significantly different between the two groups. CONCLUSIONS: Initiation of pharyngeal cooling before or immediately after the return of spontaneous circulation is safe and feasible. Pharyngeal cooling can rapidly decrease tympanic temperature without adverse effects on circulation or the pharyngeal epithelium
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