Konkuk University

About: Konkuk University is a education organization based out in Seoul, South Korea. It is known for research contribution in the topics: Population & Apoptosis. The organization has 13405 authors who have published 27027 publications receiving 506313 citations.

PPAR agonists treatment is effective in a nonalcoholic fatty liver disease animal model by modulating fatty-acid metabolic enzymes

Abstract: Background and Aims: In a previous study, the authors found that reduced expression of peroxisome proliferator-activated receptor (PPAR)-α might play an important role in developing nonalcoholic fatty liver disease (NAFLD). The aim of this study was to analyze the effects of PPAR-α and -γ agonists on NAFLD and verify the mechanisms underlying the PPAR-α and -γ agonist-induced improvements by evaluating the hepatic gene expression profile involved in fatty-acid metabolism, using the Otsuka–Long Evans–Tokushima fatty (OLETF) rat. Methods: Rats were assigned to a control group (group I), fatty liver group (group II), PPAR-α agonist treatment group (group III), or PPAR-γ agonist treatment group (group IV). Fasting blood glucose, total cholesterol, and triglycerides were measured. Liver tissues from each group were processed for histological and gene expression analysis. mRNAs of enzymes involved in fatty-acid metabolism and tumor necrosis factor (TNF)-α were measured. Results: After 28 weeks treatment with PPAR-α or -γ agonist, steatosis of the liver was improved in groups III and IV compared with group II. Fasting blood glucose levels were significantly lower in groups III and IV than in group II. In group III, mRNA expression of fatty-acid β-oxidation enzymes, such as fatty-acid transport protein (FATP), fatty-acid binding protein, carnitine palmitoyltransferase II, medium-chain acyl-CoA dehydrogenase (MCAD), long-chain acyl-CoA dehydrogenase, and acyl-CoA oxidase, was significantly increased. However, the treatment-induced modulation of fatty-acid β-oxidation enzymes was confined to FATP and MCAD in group IV. TNF-α tended to be reduced in groups III and IV compared with group II. Conclusions: Treatment with PPAR agonists, especially a PPAR-α agonist, improved the histological and biochemical parameters in the OLETF rat model by inducing fatty-acid metabolic enzymes.

Estrogen and Exercise May Enhance β-Cell Function and Mass via Insulin Receptor Substrate 2 Induction in Ovariectomized Diabetic Rats

Abstract: The prevalence and progression of type 2 diabetes have increased remarkably in postmenopausal women. Although estrogen replacement and exercise have been studied for their effect in modulating insulin sensitivity in the case of insufficient estrogen states, their effects on β-cell function and mass have not been studied. Ovariectomized (OVX) female rats with 90% pancreatectomy were given a 30% fat diet for 8 wk with a corresponding administration of 17β-estradiol (30 μg/kg body weight) and/or regular exercise. Amelioration of insulin resistance by estrogen replacement or exercise was closely related to body weight reduction. Insulin secretion in first and second phases was lower in OVX during hyperglycemic clamp, which was improved by estrogen replacement and exercise but not by weight reduction induced by restricted diets. Both estrogen replacement and exercise overcame reduced pancreatic β-cell mass in OVX rats via increased proliferation and decreased apoptosis of β-cells, but they did not exhibit an a...

Solution-Processible Crystalline NiO Nanoparticles for High-Performance Planar Perovskite Photovoltaic Cells

Abstract: In this work, we report on solution-based p-i-n-type planar-structured CH3NH3PbI3 perovskite photovoltaic (PV) cells, in which precrystallized NiO nanoparticles (NPs) without post-treatment are used to form a hole transport layer (HTL). X-ray diffraction and high-resolution transmission electron microscopy showed the crystallinity of the NPs, and atomic force microscopy and scanning electron microscopy confirmed the uniform surfaces of the resultant NiO thin film and the subsequent perovskite photoactive layer. Compared to the conventional poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) HTL, the NiO HTL had excellent energy-level alignment with that of CH3NH3PbI3 and improved electron-blocking capability, as analyzed by photoelectron spectroscopy and diode modeling, resulting in Voc ~0.13 V higher than conventional PEDOT:PSS-based devices. Consequently, a power conversion efficiency (PCE) of 15.4% with a high fill factor (FF, 0.74), short-circuit current density (Jsc, 20.2 mA·cm−2), and open circuit voltage (Voc, 1.04 V) having negligible hysteresis and superior air stability has been achieved.