Browsing by Author "Chang, Yi-Chun"

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Antioxidative and hepatoprotective effects of magnolol on acetaminophen-induced liver damage in rats
(2009-02-01)
Chen, Yung-Hsiang
;
Lin, Feng-Yen
;
Liu, Po-Len
;
Huang, Yi-Tsau
;
Chiu, Jen-Hwey
Acute liver failure (ALF), an often fatal condition characterized by massive hepatocyte necrosis, is frequently caused by drug poisoning, particularly with acetaminophen (N-acetyl-p-aminophenol/APAP). Hepatocyte necrosis is consecutive to glutathione (GSH) depletion and mitochondrial damage caused by reactive oxygen species (ROS) overproduction. Magnolol, one major phenolic constituent of Magnolia officinalis, have been known to exhibit potent antioxidative activity. In this study, the anti-hepatotoxic activity of magnolol on APAP-induced toxicity in the Sprague-Dawley rat liver was examined. After evaluating the changes of several biochemical parameters in serum, the levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and lactate dehydrogenase (LDH) were elevated by APAP (500 mg/kg) intraperitoneal administration (8 and 24 h) and reduced by treatment with magnolol (0.5 h after APAP administration; 0.01, 0.1, and 1 mu g/kg). Histological changes around the hepatic central vein, lipid peroxidation (thiobarbituric acid-reactive substance/TBARS), and GSH depletion in liver tissue induced by APAP were also recovered by magnolol treatment. The data show that oxidative stress followed by lipid peroxidation may play a very important role in the pathogenesis of APAP-induced hepatic injury; treatment with lipid-soluble antioxidant, magnolol, exerts anti-hepatotoxic activity. Our study points out the potential interest of magnolol in the treatment of toxic ALF.
Arginine-Assisted Formation of Hierarchical TiO2 Microspheres for Lithium-Ion and Sodium-Ion Battery Applications
(2016-12)
Chang, Yi-Chun
;
Wang, Yu-Xuan
;
Lee, Chi-Young
;
Chiu, Hsin-Tien
;
應用化學系
A facile route was established to synthesize hierarchically structured high specific surface area (122 m(2)g(-1)) TiO2 microspheres (diameter: 0.5-1 mu m). In a heated Teflon-coated stainless-steel autoclave, titanium tetrabutoxide Ti(OBu)(4), arginine, and absolute ethanol were reacted via the solvothermal reaction to generate the TiO2 precursor. The as-formed precursor solid was further processed at 673K under air to generate the TiO2 microspheres of nanosheets (thickness: 18 nm). The products were examined as potential anode materials for Li-ion and Na-ion batteries. After 100 cycles at 0.1 C (1C = 335 mAhg(-1)), the assembled batteries showed respectable specific capacity 241 mAhg(-1) and 145 mAhg(-1) for Li-ion and Na-ion batteries, respectively.
Bio-ingredient assisted formation of porous TiO2 for Li-ion battery electrodes
(2015-01-01)
Chang, Yi-Chun
;
Peng, Chih-Wei
;
Chen, Po-Chin
;
Lee, Chi-Young
;
Chiu, Hsin-Tien
Macroporous TiO2 was synthesized by using low-cost bio-ingredients as the pore forming templates. TiCl4 in C2H5OH(l) containing NH4OH(aq.) was polymerized in the presence of instant yeast and glucose. The organic-inorganic hybrid precursor was further processed to generate macroporous anatase TiO2 (pore size: 2.5-3 mu m) with mesopores (4-51 nm). The porous TiO2 was coated with a thin layer of carbon by chemical vapour deposition to generate the hierarchical C/TiO2 nanocomposite material. The porous products were investigated as anode materials for Li-ion batteries. The capacities of the hierarchical C/TiO2 electrode material remained 180 mA h g(-1) and 142 mA h g(-1) under high charge/discharge rates of 5 C and 10 C, respectively. It demonstrated good cycling stability of 318 mA h g(-1) at 0.1 C at various discharge-charge rates. The excellent performance is attributed to the high specific surface areas and open spaces of the C/TiO2 allowing effortless intercalation/deintercalation of Li ions.
Differential Stereocontrolled Formation of Tricyclic Triterpenes by Mutation of Tyrosine 99 of the Oxidosqualene-Lanosterol Cyclase from Saccharomyces cerevisiae
(2009-11-01)
Wu, Tung-Kung
;
Li, Wen-Hsuan
;
Chang, Cheng-Hsiang
;
Wen, Hao-Yu
;
Liu, Yuan-Ting
The function of the Tyr99 residue from Saccharomyces cerevisiae oxidosqualene-lanosterol cyclase (ERG7) was analyzed by constructing deletion and site-saturated mutants. Two truncated intermediates, (13 alpha H)-isomalabarica-14Z,17E,21-trien-3 beta-ol and (13 alpha H)-isomalabarica-14E,17E,21-trien-3 beta-ol, were isolated from the ERG7(Y99X) mutants. These results suggest that the functional role of ERG7(Y99) is to affect both chair-boat 6-6-5 tricyclic Markovnikov C-14 cation stabilization and the stereochemistry of the protons at the C-15 position for subsequent deprotonation. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Hemoglobin induced oxidative stress is associated with both endogenous peroxidase activity and H2O2 generation from polyunsaturated fatty acids
(2010-04-01)
Cheng, Tsai-Mu
;
Pan, Ju-Pin
;
Chen, Hong-Wei
;
Chang, Yi-Chun
;
Chang, Chia-Ching
Mutation of isoleucine 705 of the oxidosqualene-lanosterol cyclase from Saccharomyces cerevisiae affects lanosterol's C/D-ring cyclization and 17 alpha/beta-exocyclic side chain stereochemistry
(2011)
Wu, Tung-Kung
;
Chang, Yi-Chun
;
Liu, Yuan-Ting
;
Chang, Cheng-Hsiang
;
Wen, Hao-Yu
Site-saturated substitution in Saccharomyces cerevisiae oxidosqualene-lanosterol cyclase at Ile705 position produced three chair-boat-chair (C-B-C) truncated tricyclic compounds, two 17 alpha-exocyclic protosteryl intermediates, two protosteryl C-17 truncated rearranged intermediates and the normal biosynthetic product, lanosterol. These results indicated the importance of the Ile705 residue in affecting lanosterol's C/D ring stabilization including 6-6-5 tricyclic and protosteryl C-17 cations and 17 alpha/beta-exocyclic side chain stereochemistry.
Porous Inorganic Materials from Living Porogens: Channel-like TiO2 from Yeast-Assisted Sol-Gel Process
(2014-01-08)
Chang, Yi-Chun
;
Lee, Chi-Young
;
Chiu, Hsin-Tien
;
應用化學系
;
Department of Applied Chemistry
Vitality of yeast cells maintained in an aqueous sol-gel solution containing titanium tetraisopropoxide and glucose. The living cells and their metabolites acted as the porogens for a channel-like TiO2 precursor. Further processing of the precursor offered a channel-like meso/macroporous TiO2, a potential anode material for Li-ion battery.
Size-controlled wurtzite zinc oxide spheres with the characteristics of visible absorption and Mie scattering
(2014)
Chen, Ting-Ting
;
Chang, I-Chun
;
Tsai, Min-Chiao
;
Chang, Yi-Chun
;
Yang, Min-Han
The enhancement of the light harvesting efficiency over a metal oxide is crucial to optic-related applications which can convert solar energy into chemical energy. Here, we demonstrated a method to develop the characteristics of visible light absorption and visible Mie scattering over wurtzite ZnO microspheres. Size-controlled ZnO microspheres were successfully prepared in the thermal decomposition of amorphous/ layered basic zinc salt (LBZ) spheres. Firstly, trisodium citrate was employed as the chelating agent to synthesize amorphous/LBZ microspheres in a nucleation-controlled method. The sphere size was controlled by the nuclei number, which depends on the competition between hydroxyl ions and citrate to the ligand with Zn2+. Secondly, visible-active wurtzite ZnO spheres were obtained by thermal decomposition. The uniform sized microspheres exhibited Mie scattering in the visible range due to the interaction with specific incident electromagnetic radiation, and the full absorption spectrum was easily obtained by tuning the size of the spheres. Such uniform spheres exhibited superior visible absorption and scattering effects and thus are expected to be good candidates for the optic-related applications.
The "cascade effect" of nano/micro hierarchical structure: A new concept for designing the high photoactivity materials - An example for TiO2
(2013-10-01)
Chen, Po-Chin
;
Tsai, Min-Chiao
;
Yang, Min-Han
;
Chen, Ting-Ting
;
Chen, Huang-Chin
The chrysanthemum-like TiO2 (CT800) was synthesized. It exhibited excellent photoactivity, which greatly exceeded that of conventional P25. To discover the key factors that governed the photocatalytic properties, the specific reduction of Ag+ ions was carried out and EPR spectra of CT800 were obtained. Both an HADDF image and EDX mapping indicated that the Ag+ ions tended to be reduced close to the center of the micro matrix of CT800. Moreover, the EPR spectra strongly suggest that the excited electrons tended to migrate toward the center of the micro matrix, resulting from a multiple junction, cascade effect, which efficiently reduces the recombination of excited electrons and holes and greatly increases the photoactivity. Additionally, the special morphology of CT800 was responsible for the hot spots at the surface of nano sheets and then contributing to its outstanding photocatalytic activity. Furthermore, the unidirectional electron transfer, because of the cascade effect, by materials of different sizes provides a new avenue for the design of electronic and photoelectrochemical devices. (c) 2013 Elsevier B.V. All rights reserved.
Using Multi-Sensor System for Measuring Finger Trembling, and Applied to Neurodegenerative Disease
(2017-01-01)
Chang, Yi-Chun
;
Chen, Tzu-Pin
;
Yip, Bak Sau
;
Ching, Yu-Tai
;
資訊工程學系
Finger trembling is a feature for neurodegenerative diseases. Accessing the trembling of fingers can help diagnosis or monitoring of progression of the disease. Currently, tremogram is used in the hospital to measure the trembling of a finger. Tremogram is a single and uniaxial acceleration gauge. Using the tremogram, only the trembling direction of a finger can be measured. The direction and the finger are determined by the physician. This work studied the possibility to employ the Leap Motion and the G-sensor/gyro to access the trembling of the five fingers. Experimental results demonstrated positive answers that a G-sensor/gyro system can access not just only those information obtained from the tremogram, we can derive more information.