Browsing by Author "Chuang, Hung-Yi"

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Degradation induced variation of LC transition of poly(n-undecyl isocyanate)
(2008-05-01)
Hsieh, Bi-Zen
;
Chuang, Hung-Yi
;
Chao, Liang
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Huang, Ying-Jie
;
Tseng, Po-Hao
The first-order thermal transitions including side-chain melting, crystal-LC, biphasic chimney-like, and isotropic transitions of poly(n-undecyl isocyanate) (PUDIC) were investigated by varying its thermal history. After annealing at 140 degrees C for different periods of time, it leads to different degrees of backbiting degradation into n-undecyl isocyanurate trimer which behaves as a solvent for the rest non-degraded/rigid PUDIC to change into a lyotropic LC from thermotropic transition. Based on the degree of degradation, various amounts of trimers are present and the PUDIC demonstrates different types of thermal transitions found in DSC thermograms due to the variation of the non-degraded PUDIC concentration in solvent trimers. Finally, a phase diagram includes all types of crystallines, LC, and isotropic regions can be drawn according to the DSC thermograms. (C) 2008 Elsevier Ltd. All rights reserved.
Formation mechanism of a nanotubular polyanilines prepared by an emulsion polymerization without organic solvent
(2008-09-09)
Hsieh, Bi-Zen
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Chuang, Hung-Yi
;
Chao, Liang
;
Li, Yu-Jen
;
Huang, Ying-Jie
A nanotubular polyaniline (PANINT) was prepared from a simple emulsified polymerization method without oil solvent present. A mechanism of the formation of the nano-fibers/tubes was proposed to show that it started with the connecting arrangement of the neighboring anilinium micelles before and during polymerization, which resulted in the formation of the intermediate morphology of centipedes converting into rod-like nanofibers later. The obtained PANINTs displayed not only nanofibrous structure but owned an unusual dispersing behavior in toluene. SEM and TEM showed the dendrite-like networks of nanofibers connected and glued together by the free (not complexed to polyaniline backbone) n-dodecylbenzene sulfonic acid (DBSA) molecules. After removing the free DBSA by acetone, the clear/well-defined empty nanotubes can be seen from TEM in the magnified micrograph. The Atomic force microscopic (AFM) microgaphs demonstrated the cottage like surface morphology of the un-perturbed PANINTs and the morphology was converted to an anisotropic/oriented rods after rubbing on the wet/ cast PANINTs' dispersion of toluene before entire evaporation. (c) 2008 Published by Elsevier Ltd.
Higher NAFLD fibrosis score is associated with impaired eGFR
(2020-01-01)
Hsieh, Meng-Hsuan
;
Wu, Kuan-Ta
;
Chen, Yi-Yu
;
Yang, Jeng-Fu
;
Lin, Wen-Yi
Background/Purpose: Chronic kidney disease (CKD) has become a worldwide health problem, leading to high morbidity and mortality, and non-alcoholic fatty liver disease (NAFLD) is considered a risk factor for CKD. The aim of this study was to explore the relationship between NAFLD fibrosis score (NFS) and the estimated glomerular filtration rate (eGFR), and identify possible risk factors related to the NFS among Taiwanese subjects. Methods: Subjects were enrolled from the database of the Department of Preventive Medicine of Kaohsiung Municipal Hsiao-Kang Hospital. The eGFR was calculated according to the Taiwanese Modification of Diet in Renal Disease (TMDRD) equation, and the NFS was employed to evaluate the fibrotic level. Results: In total, 11,376 subjects were enrolled in this study, with a mean age of 52.0 +/- 6.81 years, including 4529 (39.8%) males. A fasting sugar level >= 100 mg/dL (OR = 1.70, 95% CI = 1.52-1.87) and an abnormal waist circumference (OR = 1.81, 95% CI = 1.65-1.99) were significant factors associated with NFS (p < 0.05). Trends of a decreasing TMDRD score and an increasing NFS with increasing age were noted (p < 0.05). The NFS was significantly negatively correlated with the TMDRD score (standard coefficients: -0.067, p < 0.001). Conclusion: A higher NFS is associated with an impaired eGFR in Taiwanese subjects. Controlling risk factors, especially fasting sugar level and waist circumference, may be useful in preventing NFS deterioration, which is negatively correlated with the eGFR. Copyright (C) 2019, Formosan Medical Association. Published by Elsevier Taiwan LLC.
Risk of hepatitis C virus infection in injecting and noninjecting drug users receiving opioid substitution therapy
(2020-05-01)
Wang, Chih-Wen
;
Chuang, Hung-Yi
;
Chiang, Hung-Che
;
Huang, Po-Chin
;
Yu, Ming-Lung
Background: Hepatitis C virus (HCV) is the most common viral infection among illicit drug users in the world. Although intervention of needle and syringe program and opioid substitution therapy had engaged to prevent HCV infection, the prevalence of HCV infection does not seem to decline. The aim of this study was to estimate the risk of HCV infection in injecting drug users (IDUs) and noninjecting drug users (NIDUs) receiving opioid substitution therapy. Methods: We recruited 1179 heroin-dependent patients (age: 20-66 years) under opioid substitution therapy from 2012 to 2015 in a Psychiatric Center, Southern Taiwan. The data of HCV, hepatitis B virus and HIV infection and liver biochemical examination were obtained. We used multivariate logistic regression analysis to predict the risk of HCV infection. Results: There were 93.1% of IDUs and 68.1% of NIDUs positive for HCV infection. In IDUs, HIV infection, age of heroin initiation, duration and dose of heroin use, frequency of detoxification, and number of criminal conviction were significantly associated with HCV infection. In NIDUs, snort/sniff heroin exhibited a significantly increased risk of HCV infection. Intravenous injecting (odds ratio [OR] = 23.10, 95% CI = 8.04-66.40, p < 0.001), intravenous injecting combined snort/sniff (OR = 12.95, 95% CI = 3.90-42.97, p < 0.001), and snort/sniff (OR = 4.14, 95% CI = 1.30-13.18, p = 0.016) were significantly associated with increased risk of HCV infection compared with smoking. The trend was significant (p for trend <0.001). Conclusion: In Taiwan, IDUs had harmful characteristics compared with NIDUs and both had extremely high prevalence of HCV infection. We provided evidence that snort/sniff is a possible way of leak in HCV infection despite needle-syringes supplement program been provided. Opioid substitution therapy program should include HCV assessment and treatment in the new direct-acting antiviral therapy era.
Synthesis and characterization of a novel proton-exchange membrane for fuel cells operating at high temperatures and low Humidities
(2008-03-15)
Chaung, Ching-Nan
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Chao, Liang
;
Huang, Ying-Jie
;
Hsieh, Tar-Hwa
;
Chuang, Hung-Yi
The synthesis of a p-toluidine/formal dehyde (PTF) resin was performed, and the effects of the molar ratio of the individual monomers and the polymerization conditions on the structure of the PTF resin were studied. Fourier transform infrared and C-13-NMR spectra were used to characterize the PTF. Wide-angle X-ray diffraction patterns revealed the crystalline structures of various PTFs. Polarized optical microscopy revealed that the molar ratio of the monomers had a strong effect on the crystalline morphologies. A longer polymerization time turned out a polymer with a higher intrinsic viscosity and molecular weight, which led to differences in the proton conductivity. All of the PTFs showed a higher proton conductivity than a commercial Nafion membrane at 90-100 degrees C and 0% relative humidity. The proton conductivity of the PTF series could be improved by sulfonation with sulfuric acid and could be maintained after blending with polyurethane. Pure methanol could be used as a fuel source because of the insolubility and nonwetting properties of PTF in methanol to increase the output current density for a PTF membrane electrode assembly. (C) 2007 Wiley Periodicals, Inc.