102 research outputs found
Room temperature near-ultraviolet emission from In-rich InGaN/GaN multiple quantum wells
We grew In-rich InGaNGaN multiple quantum wells (MQWs) using growth interruption (GI) by metalorganic chemical vapor deposition. The quality of overgrown InGaNGaN QW layers in MQWs was largely affected by the crystalline quality and interfacial abruptness of the underlying QW layer. Introduction of 10 s GI was very effective in improving the crystalline quality and interfacial abruptness of InGaN QW layers, and we grew a ten periods of 1-nm -thick In-rich InGaNGaN MQW with 10 s GI and obtained a strong near-ultraviolet (UV) emission (~390 nm) at room temperature. We believe that use of less than 1-nm -thick In-rich InGaN MQW can be a candidate for near-UV source, which might replace the conventional low-indium content (<10%), thicker InGaN QW layer.open313
Self-activated ultrahigh chemosensitivity of oxide thin film nanostructures for transparent sensors
One of the top design priorities for semiconductor chemical sensors is developing simple, low-cost, sensitive and reliable sensors to be built in handheld devices. However, the need to implement heating elements in sensor devices, and the resulting high power consumption, remains a major obstacle for the realization of miniaturized and integrated chemoresistive thin film sensors based on metal oxides. Here we demonstrate structurally simple but extremely efficient all oxide chemoresistive sensors with similar to 90% transmittance at visible wavelengths. Highly effective self-activation in anisotropically self-assembled nanocolumnar tungsten oxide thin films on glass substrate with indium-tin oxide electrodes enables ultrahigh response to nitrogen dioxide and volatile organic compounds with detection limits down to parts per trillion levels and power consumption less than 0.2 microwatts. Beyond the sensing performance, high transparency at visible wavelengths creates opportunities for their use in transparent electronic circuitry and optoelectronic devices with avenues for further functional convergence.open181
Alcohol use behaviors and risk of metabolic syndrome in South Korean middle-aged men
<p>Abstract</p> <p>Background</p> <p>It is thought that small volumes of alcohol may have positive effects on health. However, excessive drinking results in serious health problems. An accurate method to determine individual alcohol use behaviors are needed to assess objectively the extent to which drinking affects health. This study investigated the association between risk of metabolic syndrome (MetS) and alcohol use behaviors in middle-aged South Korean men using the Alcohol Use Disorders Identification Test.</p> <p>Methods</p> <p>This study used data from the South Korea National Health and Nutrition Examination (KNHANES) IV (2008), which extracted the standard survey household by using the proportional systematic sampling method. Data of 714 participants from KNHANES IV, 2008 were analyzed using Surveyfreq and Surveylogistic regression to investigate the association between MetS and alcohol use behaviors in middle-aged South Korean men.</p> <p>Results</p> <p>After adjustment for education, smoking, and physical activity, alcohol use behaviors were significantly associated with an increased risk of hypertension [odds ratio (OR) = 2.54, 95% confidence interval (CI) = 1.5-4.06 in the hazardous group; OR = 2.99, 95% CI = 1.84-4.92 in the problem group]; impaired fasting glucose (OR = 2.15, 95% CI = 1.16-3.99 in the hazardous group; OR = 2.48, 95% CI = 1.42-4.33 in the problem group); dyslipidemia (OR = 2.19, 95% CI = 1.38-3.47 in the problem group); abdominal obesity (OR = 1.93, 95% CI = 1.17-3.19 in the hazardous group; OR = 1.85, 95% CI = 1.17-2.92 in the problem group); and MetS (OR = 2.16, 95% CI = 1.24-3.77 in the hazardous group; OR = 2.54, 95% CI = 1.41-4.58 in problem group).</p> <p>Conclusions</p> <p>This study found that excessive alcohol use behaviors increased the risk of hypertension, diabetes, dyslipidemia, abdominal obesity, and MetS. Considering the rising rate of alcohol consumption and heavy drinking at single sittings, a culture of less risky alcohol consumption must be established to promote health among middle-aged men.</p
Análisis de las Estrategias Metodológicas implementadas por el docente en el desarrollo del proceso de enseñanza- aprendizaje en la disciplina de Geografía e Historia de Nicaragua y su Didáctica en los alumnos/as de Primer año “B” del turno regular de Formación Inicial Docente en la Escuela Normal Central de Managua Alesio Blandón Juárez durante el I semestre del Curso Escolar 2016
El presente trabajo de investigación tiene como finalidad analizar la efectividad que tienen las Estrategias Metodológicas implementadas por el docente en el desarrollo del proceso de enseñanza- aprendizaje en la disciplina de Geografía de Nicaragua y su Didáctica en los alumnos/as de Primer año “B” del turno regular de Formación Inicial Docente en la Escuela Normal Central de Managua Alesio Blandón Juárez durante el I semestre del Curso Escolar 2016. Dicho trabajo de investigación tiene un enfoque naturista o cualitativo, es una vía de transformación social, a través de la cual el ser humano descubre la realidad que le rodea, determina los medios y procedimientos para actuar sobre ella y transformarla de acuerdo a una intensión social. Los procesos de investigación cualitativa, tienen como finalidad primordial la generación y construcción de conocimientos que contribuyen al desarrollo social y personal de cada uno de los miembros de una comunidad. La fase de recolección de los datos de la investigación desarrollada, se realizó de dos formas: una información que se recogió mediante la observación directa del comportamiento de los informantes claves y una información que se obtuvo mediante la interrogación de algunos informantes claves. Para ello, primeramente el investigador realizo una inmersión en el campo de trabajo, con el propósito de identificar los lugares adecuados para recoger y producir la información necesaria y requerid
Electron Exchange Process Control Between Silver Nanoparticles and Metal-Oxides for Highly Selective Gas Detection
A highly-selective gas detection strategy is described based on the continuous iteration method of various kinds of nanowires (WO3, TiO2, SnO2, CuO, and ZnO) growth at a wafer level and the catalytic functions of silver nanoparticles. The catalytic process occurring on the silver and the nanowires depended on the magnitude of barrier height at the interface. It determined the electron exchange rate across the interface and the resulting band bending was changed near the interface when it was exposed to gases, resulted in different gas responses among the nanowires. The sensor array with palladium and silver nanoparticles was tested for the ability to distinguish between the hydrogen, carbon monoxide, and nitric oxide with detection limits ranging from sub-ppm to ppm levels, enabled the gas responses to be separated into three classes using linear discriminant analysi
Comparison of ramosetron and ondansetron for the treatment of established postoperative nausea and vomiting after laparoscopic surgery: a prospective, randomized, double-blinded multicenter trial
Yong Seon Choi,1,* Hye-Min Sohn,2,* Sang-Hwan Do,2 Kyeong Tae Min,1 Jae Hee Woo,3 Hee Jung Baik3 1Department of Anesthesiology and Pain Medicine, Anesthesia and Pain Research Institute, Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea; 2Department of Anesthesiology and Pain Medicine, Seoul National University Bundang Hospital, Seongnam, Republic of Korea; 3Department of Anesthesiology and Pain Medicine, College of Medicine, Ewha Womans University, Seoul, Republic of Korea *These authors contributed equally to this work Background: Postoperative nausea and vomiting (PONV) is a common complication after surgery, which increases physical and psychological discomfort and delays recovery. The aim of this study was to test the hypothesis that ramosetron is comparable to ondansetron for the treatment of established PONV after laparoscopic surgery using a prospective, randomized, double-blinded, noninferiority study.Methods: Patients who had at least two risk factors of PONV and underwent laparoscopic surgery under general anesthesia were assessed for eligibility. Patients who developed PONV within the first 2 h after anesthesia received ondansetron (4 mg) or ramosetron (0.3 mg) intravenously in a randomized double-blind manner. Patients were then observed for 24 h after drug administration. The incidence of nausea and vomiting, severity of nausea, rescue antiemetic necessity, and adverse effects at 0–2 or 2–24 h after drug administration was evaluated. The primary endpoint was the rate of patients exhibiting a complete response, defined as no emesis and no further rescue antiemetic medication for 24 h after drug administration.Results: Among the 583 patients, 210 (36.0%) developed PONV and were randomized to either the ondansetron (n=105) or ramosetron (n=105) group. Patient’s characteristics were similar between the groups. The complete response rate was 44.1% in the ondansetron group and 52.9% in the ramosetron group after 24 h of initial antiemetic administration. The incidence of adverse events was not different between the groups.Conclusion: We found evidence to support the noninferiority of ramosetron (0.3 mg) compared to ondansetron (4 mg) for the treatment of established PONV in moderate to high-risk patients undergoing laparoscopic surgery. Keywords: laparoscopic surgery, ondansetron, postoperative nausea and vomiting, ramosetron, non-inferiority, antiemeti
Control of NOx emissions from diesel engine by selective catalytic reduction (SCR) with urea
Among the catalysts screened, Cu-ion exchanged ZSM5 zeolite exhibited the highest NO removal activity, particularly at low reaction temperatures below 200 degreesC, maintaining a wide operating temperature window. The hydrothermal stability of the CuZSM5 catalyst can be improved by the optimization of metal content of the catalyst. Through the variation of reactor operating conditions, NO conversion of better than 90% could be achieved with a minimum NH3 slip. The decomposition of urea was also examined and a kinetic model for both thermal and catalytic decomposition of urea was developed. Urea-SCR over the CuZSM5 catalyst exhibited that the NO removal activity is competitive to that by NH3-SCR, indicating urea can be effectively utilized in SCR reactor system as the reducing agent.X1184sciescopu
Preparation of Cucurbituril Anchored Silica Gel by Cross Polymerization and Its Chromatographic Applications
A new chromatographic stationary phase has been prepared by cross polymerization between allylsilica and perallyloxycucurbit[6]uril and characterized by elemental analysis and FT-IR spectroscopy. The double end-capping has been proven to improve the separation efficiency of the cucurbituril-based stationary phase material. The first end-capping was carried out when allylsilica was made. The second end-capping was done as the final step of the whole process, and the use of a mixture of hexamethyldisilazane (HMDS) and trimethylchlorosilane (TMCS) as an end-capping reagent was found better than the use of only HMDS or TMCS. Our stationary phase has shown generally good results in separation of nonpolar and polar analytes. This phase showed even better separation performance than the commercial C18 phase for the case where host-guest chemistry was properly incorporated in solute retention.X1119sciescopuskc
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