40 research outputs found

    Experimental study on the effect of initial liquid droplet size on the evaporation in a heterogeneous droplet

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    [EN] In the present work, we experimentally investigated the effect of initial liquid droplet size on the evaporation in the heterogeneous droplet. Spherical carbon and water were used for particle and liquid droplet comprising the heterogeneous droplet. four initial droplet volumes of 1, 2, 3 and 4 μl were considered when the diameter of the particle was 5 mm. The heterogeneous droplet was suspended with a rod at 20 cm away from the radiator which surface temperature was fixed to 473 K. Ambient temperature and relative humidity remained 296 K and 40 %, respectively, during the experiment. As the results, the evaporation rate of 4 μl case increased about 1.8 times compared with that of 1 μl case. The evaporation rate increased almost linearly with the volume ratio, and that is related closely with the contact surface between particle and water droplet. Contact surface area remained almost constantly with time, whereas it increased with the initial volume of water droplet. The energy from radiator can be accumulated at the contact surface at the side of particle, thereby intensifying the evaporation of water droplet because more heat transfers from particle to droplet through the contact surface. Consequently, the initial volume of liquid droplet is one of the influence factors on the evaporation rate in the heterogenous droplet.This research was supported by the Fire Fighting Safety & 119 Rescue Technology Research and Development Program funded by the Ministry of Public Safety and Security (NEMA-NG-2014-46) and Research Project of Air Sampling Detector funded by Alllitelife co. Inc..Sung, KH.; Nam, JS.; Hong, GB.; Ryou, HS. (2017). Experimental study on the effect of initial liquid droplet size on the evaporation in a heterogeneous droplet. En Ilass Europe. 28th european conference on Liquid Atomization and Spray Systems. Editorial Universitat Politècnica de València. 290-295. https://doi.org/10.4995/ILASS2017.2017.4744OCS29029

    Comparison of the Efficacy of Glimepiride, Metformin, and Rosiglitazone Monotherapy in Korean Drug-Naïve Type 2 Diabetic Patients: The Practical Evidence of Antidiabetic Monotherapy Study

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    BackgroundAlthough many anti-diabetic drugs have been used to control hyperglycemia for decades, the efficacy of commonly-used oral glucose-lowering agents in Korean type 2 diabetic patients has yet to be clearly demonstrated.MethodsWe evaluated the efficacy of glimepiride, metformin, and rosiglitazone as initial treatment for drug-naïve type 2 diabetes mellitus patients in a 48-week, double-blind, randomized controlled study that included 349 Korean patients. Our primary goal was to determine the change in HbA1c levels from baseline to end point. Our secondary goal was to evaluate changes in fasting plasma glucose (FPG) levels, body weight, frequency of adverse events, and the proportion of participants achieving target HbA1c levels.ResultsHbA1c levels decreased from 7.8% to 6.9% in the glimepiride group (P<0.001), from 7.9% to 7.0% in the metformin group (P<0.001), and from 7.8% to 7.0% (P<0.001) in the rosiglitazone group. Glimepiride and rosiglitazone significantly increased body weight and metformin reduced body weight during the study period. Symptomatic hypoglycemia was more frequent in the glimepiride group and diarrhea was more frequent in the metformin group.ConclusionThe efficacy of glimepiride, metformin, and rosiglitazone as antidiabetic monotherapies in drug-naïve Korean type 2 diabetic patients was similar in the three groups, with no statistical difference. This study is the first randomized controlled trial to evaluate the efficacy of commonly-used oral hypoglycemic agents in Korean type 2 diabetic patients. An additional subgroup analysis is recommended to obtain more detailed information

    Atrasentan and renal events in patients with type 2 diabetes and chronic kidney disease (SONAR): a double-blind, randomised, placebo-controlled trial

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    Background: Short-term treatment for people with type 2 diabetes using a low dose of the selective endothelin A receptor antagonist atrasentan reduces albuminuria without causing significant sodium retention. We report the long-term effects of treatment with atrasentan on major renal outcomes. Methods: We did this double-blind, randomised, placebo-controlled trial at 689 sites in 41 countries. We enrolled adults aged 18–85 years with type 2 diabetes, estimated glomerular filtration rate (eGFR)25–75 mL/min per 1·73 m 2 of body surface area, and a urine albumin-to-creatinine ratio (UACR)of 300–5000 mg/g who had received maximum labelled or tolerated renin–angiotensin system inhibition for at least 4 weeks. Participants were given atrasentan 0·75 mg orally daily during an enrichment period before random group assignment. Those with a UACR decrease of at least 30% with no substantial fluid retention during the enrichment period (responders)were included in the double-blind treatment period. Responders were randomly assigned to receive either atrasentan 0·75 mg orally daily or placebo. All patients and investigators were masked to treatment assignment. The primary endpoint was a composite of doubling of serum creatinine (sustained for ≥30 days)or end-stage kidney disease (eGFR <15 mL/min per 1·73 m 2 sustained for ≥90 days, chronic dialysis for ≥90 days, kidney transplantation, or death from kidney failure)in the intention-to-treat population of all responders. Safety was assessed in all patients who received at least one dose of their assigned study treatment. The study is registered with ClinicalTrials.gov, number NCT01858532. Findings: Between May 17, 2013, and July 13, 2017, 11 087 patients were screened; 5117 entered the enrichment period, and 4711 completed the enrichment period. Of these, 2648 patients were responders and were randomly assigned to the atrasentan group (n=1325)or placebo group (n=1323). Median follow-up was 2·2 years (IQR 1·4–2·9). 79 (6·0%)of 1325 patients in the atrasentan group and 105 (7·9%)of 1323 in the placebo group had a primary composite renal endpoint event (hazard ratio [HR]0·65 [95% CI 0·49–0·88]; p=0·0047). Fluid retention and anaemia adverse events, which have been previously attributed to endothelin receptor antagonists, were more frequent in the atrasentan group than in the placebo group. Hospital admission for heart failure occurred in 47 (3·5%)of 1325 patients in the atrasentan group and 34 (2·6%)of 1323 patients in the placebo group (HR 1·33 [95% CI 0·85–2·07]; p=0·208). 58 (4·4%)patients in the atrasentan group and 52 (3·9%)in the placebo group died (HR 1·09 [95% CI 0·75–1·59]; p=0·65). Interpretation: Atrasentan reduced the risk of renal events in patients with diabetes and chronic kidney disease who were selected to optimise efficacy and safety. These data support a potential role for selective endothelin receptor antagonists in protecting renal function in patients with type 2 diabetes at high risk of developing end-stage kidney disease. Funding: AbbVie

    Preoperative Diagnosis and Treatment Outcomes of Incarcerated Inferiorly Displaced Flap Tear of the Medial Meniscus: Comparison between Flap Tears with and without Incarcerated Fragment

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    The purpose of this study was to compare preoperative variables and postoperative outcomes between flap tears with and without incarceration of inferiorly displaced fragments of medial meniscus and find distinct features of incarcerated flap tear of medial meniscus to improve preoperative diagnosis. 79 patients who underwent partial meniscectomy for flap tear of medial meniscus were classified into two groups: group U, usual flap tear without incarcerated fragment; group I, flap tear with incarcerated inferiorly displaced fragment. Patient characteristics and preoperative variables including duration of symptom aggravation were investigated. A comprehensive physical examination including joint line tenderness was performed. Magnetic resonance imaging (MRI) examination was carried out on all patients. Clinical assessments were performed with functional scores including visual analogue scale (VAS), and radiologic evaluation was conducted. Preoperative values and postoperative outcomes measured at the minimum follow-up duration of 2 years were compared between the groups. The groups did not differ significantly regarding postoperative outcomes by functional and radiological evaluations (p>0.05). In making preoperative diagnosis, sensitivity of diagnosis based solely on MR images was significantly lower in group I (68.8%) than that in group U (90.5%) (p=0.040). The following clinical features differed significantly between the groups: Patients in group I had higher scores in preoperative VAS (group U = 6.6; group I = 7.7) (p=0.011) and shorter duration of symptom aggravation (group U = 13.8 weeks; group I = 3.9 weeks) (p<0.001). Joint line tenderness was positive more distinctly in group I (100%) than in group U (74.6%). If displaced flap tear was properly resected, improved outcomes did not differ regardless of incarceration of flap tear. In diagnosing incarcerated inferiorly displaced flap tear, sensitivity of diagnosis based solely on MR images could be low. Distinguishing clinical findings would be helpful in obtaining a more appropriate diagnosis

    The keys for effective distribution of intergranular voids of peapod-like MnO@C core-shell for lithium ion batteries

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    Conversion reaction-based transition metal oxides have shown high reversible capacity compared to conventional intercalation reaction-based materials. However, their practical applications have been impeded by a poor cycle life resulted from their low electrical conductivity and huge volume changes. During the past decade, remarkable advances have been achieved in the preparation of nanostructured transition metal oxides for conversion reaction anodes. Among the various shaped nanomaterials, core-shell structure with a carbon shell showed excellent electrochemical performance. Herein, we prepared peapod-like MnO@C nanowires as one special type of core-shell structure, and we elucidated the structure-properties relationship in peapod-like MnO@C nanowires for Li-ion batteries. The morphology of the manganese oxide particles inside the carbon layer could be simply controlled by adjusting the parameters in the carbonization process. The optimized composites exhibited excellent cycling performance without decreasing the capacity, and outstanding rate properties. The optimized structure can maximize the advantages such as structural durability against the stress involving huge volume changes, as well as minimize the side reaction at the surface. (C) 2019 Elsevier B.V. All rights reserved.11Nsciescopu

    Effects of Variability in Blood Pressure, Glucose, and Cholesterol Concentrations, and Body Mass Index on End-Stage Renal Disease in the General Population of Korea

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    Aim: Metabolic parameters, such as blood pressure, glucose, lipid levels, and body weight, can interact with each other, and this clustering of metabolic risk factors is related to the progression to end-stage renal disease (ESRD). The effect of variability in metabolic parameters on the risk of ESRD has not been studied previously. Methods: Using nationally representative data from the Korean National Health Insurance System, 8,199,135 participants who had undergone three or more health examinations between 2005 and 2012 were included in this analysis. Intraindividual variability in systolic blood pressure (SBP), fasting blood glucose (FBG), total cholesterol (TC), and body mass index (BMI) was assessed by examining the coefficient of variation, variability independent of the mean, and average real variability. High variability was defined as the highest quartile of variability and low variability was defined as the lower three quartiles of variability. Results: Over a median (5&#8722;95%) of 7.1 (6.5&#8722;7.5) years of follow-up after the variability assessment period, 13,600 (1.7/1000 person-years) participants developed ESRD. For each metabolic parameter, an incrementally higher risk of ESRD was observed for higher variability quartiles compared with the lowest quartile. The risk of ESRD was 46% higher in the highest quartile of SBP variability, 47% higher in the highest quartile of FBG variability, 56% higher in the highest quartile of BMI variability, and 108% higher in the highest quartile of TC variability. Compared with the group with low variability for all four parameters, the group with high variability for all four parameters had a significantly higher risk for incident ESRD (hazard ratio (HR) 4.12; 95% CI 3.72&#8722;4.57). Conclusions: Variability in each metabolic parameter was an independent predictor of the development of ESRD among the general population. There was a composite effect of the variability in additional metabolic parameters on the risk of ESRD

    Bi-MOF derived micro/meso-porous Bi@C nanoplates for high performance lithium-ion batteries

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    © The Royal Society of Chemistry 2020. Micro/meso-porous Bi@C nanoplates are synthesized by pyrolyzing Bi-based metal-organic frameworks (MOFs) prepared by a microwave-assisted hydrothermal method to overcome huge volume expansion and pulverization of anode materials during battery operation. The Bi@C nanoplates are composed of ∼10-50 nm Bi nanoparticles in an amorphous carbon shell. The material shows very high capacity (556 mA h g-1) after 100 cycles at 100 mA g-1 and good cycling performance. Moreover, the Bi@C nanoplates perform well at high current densities and have excellent cyclic stability; their capacity is 308 mA h g-1 after 50 cycles and 200 mA h g-1 after 1000 cycles at 3000 mA g-1. The outstanding performance of this anode is due to the nanosized Bi and amorphous carbon shell. The nanosized Bi reduces the diffusion length of Li ions, while the amorphous carbon shell improves the electrical conductivity of the anode and also restrains the pulverization and aggregation of the metal during cycling. The proposed hierarchical micro/meso-porous materials derived from MOFs are a new type of nanostructures that can aid the development of novel Bi-based anodes for LIBs11sci

    Amorphous iron fluorosulfate as a high-capacity cathode utilizing combined intercalation and conversion reactions with unexpectedly high reversibility

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    To achieve the desirable dual characteristics of high-capacity performance and low-cost production for the batteries of tomorrow, leveraging of multi-redox reactions of Earth-abundant transition metals in electrodes is fundamentally important. Here we identify an amorphous iron fluorosulfate electrode, a-LiFeSO4F, that can exploit both the intercalation and conversion reactions with a stable reversibility. The a-LiFeSO4F electrode delivers a capacity of 360 mAh g(-1) with similar to 98.6% capacity retention after 200 cycles even at an elevated temperature (60 degrees C). In contrast to the conventional intercalation/conversion-type electrodes, the reversible cycle stability is attributed to the inherent amorphous structure of a-LiFeSO4F, whose structural integrity is not severely disturbed even after the conversion reaction, allowing its continuation as an intercalation host. We believe that this cycle stability of the intercalation/conversion reaction can be generally extended to various amorphous intercalation materials, offering new insights into the design of high-capacity electrodes through the exploitation of multi-mechanistic lithiation processes
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