200 research outputs found

    Enzyme Attached on Polymeric Micelles as a Nanoscale Reactor

    Get PDF
    Similar to what lipase does, a surface-active enzyme was developed by attaching peroxidase on combshaped polymaleic anhydride-alt-1-tetradecene (PMA-TD) in a microemulsion system composed of n-butyl acetate and buffer solution, and its catalytic characteristics of polyphenol synthesis were investigated in an aqueous solution. The modified peroxidase with PMA-TD tended to form self-assembled aggregates like micelles in the aqueous solution and could be concentrated at solvent/water interfaces without unfolding of the enzyme. The efficiency of conversion of 2,4-dichlorophenol to phenolic oligomers was approximately 2-fold improved with the modified peroxidase compared to native peroxidase. The K m and V max values for the modified peroxidase were 1.5-fold lower and 2-fold higher, respectively. The hydrodynamic diameter of the micelle on the modified peroxidase increased with the reaction time, indicating that phenolic products were accumulated in the hydrophobic interior of micelles. In addition, the molecular weight (MW) of phenolic polymers was much larger in the system with the modified peroxidase. These observations implied that the modified peroxidase with hydrophobic side chains formed micellar structures by solubilization of phenolic products and further polymerization reaction could occur in the hydrophobic interior of the micelles

    Enzyme Attached on Polymeric Micelles as a Nanoscale Reactor

    Get PDF
    Similar to what lipase does, a surface-active enzyme was developed by attaching peroxidase on combshaped polymaleic anhydride-alt-1-tetradecene (PMA-TD) in a microemulsion system composed of n-butyl acetate and buffer solution, and its catalytic characteristics of polyphenol synthesis were investigated in an aqueous solution. The modified peroxidase with PMA-TD tended to form self-assembled aggregates like micelles in the aqueous solution and could be concentrated at solvent/water interfaces without unfolding of the enzyme. The efficiency of conversion of 2,4-dichlorophenol to phenolic oligomers was approximately 2-fold improved with the modified peroxidase compared to native peroxidase. The K m and V max values for the modified peroxidase were 1.5-fold lower and 2-fold higher, respectively. The hydrodynamic diameter of the micelle on the modified peroxidase increased with the reaction time, indicating that phenolic products were accumulated in the hydrophobic interior of micelles. In addition, the molecular weight (MW) of phenolic polymers was much larger in the system with the modified peroxidase. These observations implied that the modified peroxidase with hydrophobic side chains formed micellar structures by solubilization of phenolic products and further polymerization reaction could occur in the hydrophobic interior of the micelles

    Efficient terahertz generation in highly nonlinear organic crystal HMB-TMS

    Get PDF
    We report on generation of strong and broadband terahertz (THz) pulses via collinearly phase-matched optical rectification of near-infrared femtosecond pulses in the organic nonlinear optical HMB-TMS (2-(4-hydroxy-3-methoxystyryl)-3-methylbenzo[d]thiazol-3-ium 2,4,6-trimethylbenzenesulfonate) single crystals which exhibit optimal molecular orientation and large macroscopic optical nonlinearity for efficient THz wave generation. Single-cycle THz pulses with a peak electric field strength of 0.66 MV/cm and a bandwidth from 0.1 to 5.4 THz are achieved from an HMB-TMS crystal with only a 2-mm clear aperture pumped by 1350 nm pulses at moderate fluences. The generated THz energy is about 1 µJ and the corresponding pump-to-THz energy conversion efficiency reaches 0.23%.United States. Office of Naval Research (N00014-13-1-0509)United States. Office of Naval Research. Defense University Research Instrumentation Program (N00014-15-1-2879)Samsung Global Research Outreach ProgramNational Research Foundation of Korea (No. 2016R1A2B4011050National Research Foundation of Korea (No. 2014R1A5A1009799)National Research Foundation of Korea (No. 2015K1A3A1A14004646)National Research Foundation of Korea (No. 2009-0093826

    The Korean Mistletoe (Viscum album coloratum) Extract Has an Antiobesity Effect and Protects against Hepatic Steatosis in Mice with High-Fat Diet-Induced Obesity

    Get PDF
    This study investigates the inhibitory effects of Korean mistletoe extract (KME) on adipogenic factors in 3T3-L1 cells and obesity and nonalcoholic fatty liver disease (NAFLD) in mice fed a high-fat diet. Male C57Bl/6 mice fed a high-fat diet were treated with KME (3 g/kg/day) for 15 weeks for the antiobesity and NAFLD experiments. Body weight and daily food intake were measured regularly during the experimental period. The epididymal pad was measured and liver histology was observed. The effects of KME on thermogenesis and endurance capacity were measured. The effects of KME on adipogenic factors were examined in 3T3-L1 cells. Body and epididymal fat pad weights were reduced in KME-treated mice, and histological examination showed an amelioration of fatty liver in KME-treated mice, without an effect on food consumption. KME potently induces mitochondrial activity by activating thermogenesis and improving endurance capacity. KME also inhibited adipogenic factors in vitro. These results demonstrate the inhibitory effects of KME on obesity and NAFLD in mice fed a high-fat diet. The effects appear to be mediated through an enhanced mitochondrial activity. Therefore, KME may be an effective therapeutic candidate for treating obesity and fatty liver caused by a high-fat diet

    Multidisciplinary approach for hepatocellular carcinoma arising from cirrhotic liver with Budd-Chiari syndrome: a case report

    Get PDF
    Budd-Chiari syndrome (BCS) is defined by the obstruction of the hepatic venous outflow between the small hepatic veins and the junction of the inferior vena cava (IVC) with the right atrium. BCS with IVC obstruction occasionally progresses to hepatocellular carcinoma (HCC). Here, we report the case of a patient with HCC arising from a cirrhotic liver with BCS, in whom the hepatic portion of the IVC was obstructed, and who had a favorable outcome with a multidisciplinary approach and IVC balloon angioplasty

    Torsion of the Gallbladder: Report of a Case

    Get PDF
    Torsion of the gallbladder is a rare entity that is difficult to diagnose preoperatively. The condition occurs most often in the elderly. Although its etiology is unknown, a constant finding is the presence of the gallbladder on a mobile mesentery (floating gallbladder). Torsion, or volvulus, of the gallbladder occurs when it twists axially, with the subsequent occlusion of bile and/or blood flow. Herein, a case of torsion of the gallbladder is presented where preoperative computed tomographic scan and laparoscopy were successfully used to diagnose and treat this condition without the usual requirement of open exploration. Given the possibility of laparoscopic cholecystectomy and the increasing incidence with which torsion of the gallbladder is being witnessed today, the importance of a preoperative computed tomographic scan is emphasized when there is a high index of clinical suspicion

    A case of hemolytic uremic syndrome preceded by intussusception

    Get PDF
    Hemolytic-uremic syndrome (HUS) is the most common cause of acute renal failure in young children. It is classically characterized by the triad of microangiopathic hemolytic anemia, thrombocytopenia, and uremia. Further, not only is intussusception one of the differential diagnoses of HUS but it may also become a complication during disease progression. We report a case of HUS preceded by intussusception in a previously healthy 17-month-old boy. The patient presented at the emergency department with bloody stools that developed the day after reduction of intussusception. HUS was diagnosed 4 days after the reduction of intussusception. The patient was provided only supportive care and his laboratory test findings were normal at discharge
    • …
    corecore