280 research outputs found
Novel twin-roll-cast Ti/Al clad sheets with excellent tensile properties
Pure Ti or Ti alloys are recently spot-lighted in construction industries because they have excellent resistance to corrosions, chemicals, and climates as well as various coloring characteristics, but their wide applications are postponed by their expensiveness and poor formability. We present a new fabrication process of Ti/Al clad sheets by bonding a thin Ti sheet on to a 5052 Al alloy melt during vertical-twin-roll casting. This process has merits of reduced production costs as well as improved tensile properties. In the as-twin-roll-cast clad sheet, the homogeneously cast microstructure existed in the Al alloy substrate side, while the Ti/Al interface did not contain any reaction products, pores, cracks, or lateral delamination, which indicated the successful twin-roll casting. When this sheet was annealed at 350 degrees C-600 degrees C, the metallurgical bonding was expanded by interfacial diffusion, thereby leading to improvement in tensile properties over those calculated by a rule of mixtures. The ductility was also improved over that of 5052-O Al alloy (25%) or pure Ti (25%) by synergic effect of homogeneous deformation due to excellent Ti/Al bonding. This work provides new applications of Ti/Al clad sheets to lightweight-alloy clad sheets requiring excellent formability and corrosion resistance as well as alloy cost saving.112Ysciescopu
A case of primary aldosteronism combined with acquired nephrogenic diabetes insipidus
AbstractAldosterone-producing adrenal adenoma can induce various clinical manifestations as a result of chronic exposure to aldosterone. We report a rare case of a 37-year-old man who complained of general weakness and polyuria. He was diagnosed with aldosterone-producing adrenal adenoma and nephrogenic diabetes insipidus. Aldosterone enhances the secretion of potassium in the collecting duct, which can lead to hypokalemia. By contrast, nephrogenic diabetes insipidus, which manifests as polyuria and polydipsia, can occur in several clinical conditions such as acquired tubular disease and those attributed to toxins and congenital causes. Among them, hypokalemia can also damage tubular structures in response to vasopressin. The patient’s urine output was >3 L/d and was diluted. Owing to the ineffectiveness of vasopressin, we eventually made a diagnosis of nephrogenic diabetes insipidus. Laparoscopic adrenalectomy and intraoperative kidney biopsy were subsequently performed. The pathologic finding of kidney biopsy revealed a decrease in aquaporin-2 on immunohistochemical stain
Development of Micro-Heaters with Optimized Temperature Compensation Design for Gas Sensors
One of the key components of a chemical gas sensor is a MEMS micro-heater. Micro-heaters are used in both semiconductor gas sensors and NDIR gas sensors; however they each require different heat dissipation characteristics. For the semiconductor gas sensors, a uniform temperature is required over a wide area of the heater. On the other hand, for the NDIR gas sensor, the micro-heater needs high levels of infrared radiation in order to increase sensitivity. In this study, a novel design of a poly-Si micro-heater is proposed to improve the uniformity of heat dissipation on the heating plate. Temperature uniformity of the micro-heater is achieved by compensating for the variation in power consumption around the perimeter of the heater. With the power compensated design, the uniform heating area is increased by 2.5 times and the average temperature goes up by 40 °C. Therefore, this power compensated micro-heater design is suitable for a semiconductor gas sensor. Meanwhile, the poly-Si micro-heater without compensation shows a higher level of infrared radiation under equal power consumption conditions. This indicates that the micro-heater without compensation is more suitable for a NDIR gas sensor. Furthermore, the micro-heater shows a short response time of less than 20ms, indicating a very high efficiency of pulse driving
Cause of Chest Pain in a Patient with Previous Myocardial Infarction: Look Outside the Heart for Extracardiac Mass
We report a case of thymic carcinoma that was initially detected by echocardiography in an 80-year-old male who visited the emergency room for chest pain and had a history of myocardial infarction and percutaneous coronary intervention. Transthoracic echocardiography showed a huge extracardiac mass that was located in the anterior mediastinum and was diagnosed as a thymic carcinoma by biopsy
Prognostic Implications of the NIH Consensus Criteria in Children with Chronic Graft-versus-Host Disease
Patterns of Post-thyroidectomy Hemorrhage
ObjectivesPostoperative hemorrhage is a potentially life-threatening complication in thyroid surgery. This study was performed to review the clinical patterns of post-thyroidectomy hemorrhage, and especially as they are related to the source of bleeding.MethodsWe performed a retrospective review of 10 patients (0.96%) with post-thyroidectomy hemorrhage that required surgical evacuation. The clinical patterns such as the time interval from surgery to hemorrhage and the signs and symptoms according to the bleeding focus were evaluated.ResultsThe mean time interval from surgery to symptom onset was 7 hr 52 min. Six cases showed bleeding deep to the strap muscles, while the other 4 cases showed bleeding superficial to the muscles. Ecchymosis was prominent and dark in color in 3 of the 4 cases (75%) of superficial bleeding, however it was identified in only 2 of the 6 cases (33%) of deep bleeding. Respiratory distress occurred in two cases of hematoma deep to the strap muscles, but in none of the cases with superficial bleeding.ConclusionThe post-thyroidectomy hemorrhage had some different clinical patterns between the superficial cases and the deep cases, showing that life-threatening airway obstruction occurred from the deep hematoma. A thorough understanding of the clinical patterns of post-thyroidectomy hemorrhage between the cases of superficial and those cases of deep hematoma may provide valuable surgical tips to manage this potentially lethal complication
Experimental infection of a newly emerging Korean type I porcine reproductive and respiratory syndrome virus isolate in colostrum-deprived pigs
Profiling age-related epigenetic markers of stomach adenocarcinoma in young and old subjects
The purpose of our study is to identify epigenetic markers that are differently expressed in the stomach adenocarcinoma (STAD) condition. Based on data from The Cancer Genome Atlas (TCGA), we were able to detect an age-related difference in methylation patterns and changes in gene and miRNA expression levels in young (n = 14) and old (n = 70) STAD subjects. Our analysis identified 323 upregulated and 653 downregulated genes in old STAD subjects. We also found 76 miRNAs with age-related expression patterns and 113 differentially methylated genes (DMGs), respectively. Our further analysis revealed that significant upregulated genes (n = 35) were assigned to the cell cycle, while the muscle system process (n = 27) and cell adhesion-related genes (n = 57) were downregulated. In addition, by comparing gene and miRNA expression with methylation change, we identified that three upregulated genes (ELF3, IL1??, and MMP13) known to be involved in inflammatory responses and cell growth were significantly hypomethylated in the promoter region. We further detected target candidates for age-related, downregulated miRNAs (hsa-mir-124-3, hsa-mir-204, and hsa-mir-125b-2) in old STAD subjects. This is the first report of the results from a study exploring age-related epigenetic biomarkers of STAD using high-throughput data and provides evidence for a complex clinicopathological condition expressed by the age-related STAD progression. © the authors, publisher and licensee Libertas Academica Limitedopen
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