212 research outputs found

    Solidification microstructures of the ingots obtained by arc melting and cold crucible levitation melting in TiNbTaZr medium-entropy alloy and TiNbTaZrX (X = V, Mo, W) high-entropy alloys

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    The solidification microstructures of the TiNbTaZr medium-entropy alloy and TiNbTaZrX (X = V, Mo, and W) high-entropy alloys (HEAs), including the TiNbTaZrMo bio-HEA, were investigated. Equiaxed dendrite structures were observed in the ingots that were prepared by arc melting, regardless of the position of the ingots and the alloy system. In addition, no significant difference in the solidification microstructure was observed in TiZrNbTaMo bio-HEAs between the arc-melted (AM) ingots and cold crucible levitation melted (CCLM) ingots. A cold shut was observed in theAMingots, but not in theCCLMingots. The interdendrite regions tended to be enriched in Ti and Zr in the TiNbTaZrMEAand TiNbTaZrX (X=V, Mo, and W) HEAs. The distribution coefficients during solidification, which were estimated by thermodynamic calculations, could explain the distribution of the constituent elements in the dendrite and interdendrite regions. The thermodynamic calculations indicated that an increase in the concentration of the low melting-temperature V (2183 K) leads to a monotonic decrease in the liquidus temperature (TL), and that increases in the concentration of high melting-temperature Mo (2896 K) and W (3695 K) lead to a monotonic increase in TL in TiNbTaZrXx (X = V, Mo, and W) (x = 0 - 2) HEAs.Nagase T., Mizuuchi K., Nakano T.. Solidification microstructures of the ingots obtained by arc melting and cold crucible levitation melting in TiNbTaZr medium-entropy alloy and TiNbTaZrX (X = V, Mo, W) high-entropy alloys. Entropy, 21, 5, 483. https://doi.org/10.3390/e21050483

    Development of General-Purpose Energy System Analysis Simulator "Energy Flow +M"? Static Analysis of Solar Collector

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    To solve current environmental problems such as global warming and declination of fossil fuels, use of less energy is essential, particularly in the fields of refrigeration and air conditioning. Thus, simulations using complex mathematical models become vital. Simulation technology faces a major challenge because the language of simulation codes varies depending on the programmer. Thereafter, others cannot duplicate the same simulation technology used by their predecessors. To address this, a modular analysis method that generalizes simulation code has been developed. With this method, the general-purpose software analyzing energy system called “ENERGY FLOW +M,” a software enabling analyses that can be conducted without having to specify the model or the method of analysis used, has also been created. The focus of this study was on the solar collector. As the solar collector uses energy from the sun, it is friendly to the global environment. In order to understand the performance of the solar collector, the construction of a simulation model was carried out. Moreover, models of the solar collector and solar radiation were loaded into “ENERGY FLOW +M” to verify their performance. Thus, this simulator allows us to execute simulations of the solar collector from anywhere via the Internet

    『子不語』妬鬼説話拾遺

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    Risk Factors for Fracture in Adult Patients with Cerebral Palsy

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    Most studies on risk factors for fracture in patients with cerebral palsy have been conducted in children. We examined the relationships between age, body mass, gender, osteoporosis, osteomalacia and mobility level with history of a previous fracture in adult patients with cerebral palsy. We studied 124 institutionalized adults (52 men, age: 21-56 years, and 72 women, age: 24-47 years) with cerebral palsy. Antero-posterior radiographs of the pelvis were examined for osteoporosis and graded using the Singh index. Serum calcium, phosphate and alkaline phosphatase were measured. Osteoporosis was defined as grade 1-4 in Singh index. Osteomalacia was defined as calcium 220 U/l. Body mass index (BMI) was calculated from body height and weight. Medical records were examined for history of previous fractures and mobility levels (ambulatory /nonambulatory). A history of previous fracture was noted in 17 patients (6 men and 11 women). The proportion of osteoporosis in non-ambulatory patients was higher than in ambulatory patients. Multiple logistic regression analysis showed that presence of osteoporosis and mobility level (ambulation) were two factors that significantly correlated with a history of fracture. The latter did not correlate with age, BMI, gender and osteomalacia. Our findings suggest that osteoporosis is an important risk factor for fracture in adults with cerebral palsy. Since falling is also a risk factor for certain fractures, fractures seem to be more likely to occur in ambulatory patients through falling despite the low prevalence of osteoporosis

    Microbial Community Composition of Two Environmentally Conserved Estuaries in the Midorikawa River and Shirakawa River

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    To provide a general overview of the microbial communities in environmentally conserved estuaries, the top 5 cm of sediment was sampled from the sandy estuary of the Shirakawa River and from the muddy estuary of the Midorikawa River. Higher amounts of organic matter were detected in the Midorikawa estuary sample than in the Shirakawa estuary sample. Measurement of redox potential revealed that the Shirakawa estuary was aerobic and the Midorikawa estuary was much less aerobic. Clone analysis was performed by targeting partial 16S rRNA gene sequences and using extracted DNA from the samples as a template. Various bacteria were detected, among which Gammaproteobacteria was dominant at both estuaries. Unclassified clones were detected in the Gammaproteobacteria group, mainly among samples from the Midorikawa estuary. Other detected bacterial groups were Alphaproteobacteria, Deltaproteobacteria, Chloroflexi, Actinobacteria, and Bacteroidetes. All the Deltaproteobacteria clones were anaerobic sulfate-reducing bacteria. Those aerobic and anaerobic bacteria coexisted in the top 5 cm of the estuary sediments indicating the surface layer have active sulfur and carbon cycle. Abundance of aerobic Gammaproteobacteria may be an indicator for conserved estuaries

    Assessment of the intrapulmonary ventilation-perfusion distribution after the Fontan procedure for complex cardiac anomalies: Relation to pulmonary hemodynamics

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    AbstractIn 12 patients who underwent the Fontan procedure for complex cardiac anomalies, lung scanning with xenon-133 was performed to assess the intrapulmonary ventilation-perfusion distribution, and comparison was made with a control group. All data were then analyzed in relation to either pre- or postoperative pulmonary hemodynamic data. In ventilation scans, the intrapulmonary distribution in the right lung was almost normal.In perfusion scans, an abnormal increased upper to lower lobe perfusion ratio greater than the normal value found in the control group was noted in seven patients (58.3%). There was a significant correlation (p < 0.02) between the upper to lower lobe perfusion ratio and postoperative pulmonary vascular resistance. Furthermore, this perfusion ratio correlated inversely with the preoperative (p < 0.005) and postoperative (p < 0.02) right pulmonary artery area index, defined as the ratio of cross-sectional area to the normal value. Of five patients with < 90% arterial oxygen saturation, four showed an abnormal distribution of pulmonary blood flow greater than the normal perfusion ratio. No patient had evidence of a pulmonary arteriovenous fistula by the echocardiographic contrast study.These results suggest that abnormal distribution of pulmonary blood flow to the upper lung segment may develop in patients after the Fontan procedure, and that insufficient size of the pulmonary artery before operation and the consequent postoperative elevation of pulmonary vascular resistance may be responsible for this perfusion abnormality

    Periodontal Tissue as a Biomaterial for Hard-Tissue Regeneration following bmp-2 Gene Transfer

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    The application of periodontal tissue in regenerative medicine has gained increasing interest since it has a high potential to induce hard-tissue regeneration, and is easy to handle and graft to other areas of the oral cavity or tissues. Additionally, bone morphogenetic protein-2 (BMP-2) has a high potential to induce the differentiation of mesenchymal stem cells into osteogenic cells. We previously developed a system for a gene transfer to the periodontal tissues in animal models. In this study, we aimed to reveal the potential and efficiency of periodontal tissue as a biomaterial for hard-tissue regeneration following a bmp-2 gene transfer. A non-viral expression vector carrying bmp-2 was injected into the palate of the periodontal tissues of Wistar rats, followed by electroporation. The periodontal tissues were analyzed through bone morphometric analyses, including mineral apposition rate (MAR) determination and collagen micro-arrangement, which is a bone quality parameter, before and after a gene transfer. The MAR was significantly higher 3–6 d after the gene transfer than that before the gene transfer. Collagen orientation was normally maintained even after the bmp-2 gene transfer, suggesting that the bmp-2 gene transfer has no adverse effects on bone quality. Our results suggest that periodontal tissue electroporated with bmp-2 could be a novel biomaterial candidate for hard-tissue regeneration therapy.Kawai M.Y., Ozasa R., Ishimoto T., et al. Periodontal Tissue as a Biomaterial for Hard-Tissue Regeneration following bmp-2 Gene Transfer. Materials, 15, 3, 993. https://doi.org/10.3390/ma15030993

    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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