Browsing by Author "Chen B.-H."

Biodiesel production from transesterification of vegetable oils in excess methanol was performed by using as-prepared catalyst from low-cost kaolin clay. This effective heterogeneous catalyst was successfully prepared from natural kaolin firstly by dehydroxylation at 800. ¢XC for 10. h and, subsequently, by NaOH-activation hydrothermally at 90. ¢XC for 24. h and calcined again at 500. ¢XC for 6. h. The as-obtained catalytic material was characterized with instruments, including FT-IR, XRD, SEM, and porosimeter (BET/BJH analysis). The as-prepared catalyst was advantageous not only for its easy preparation, but also for its cost-efficiency and superior catalysis in transesterification of vegetable oils in excess methanol to produce fatty acid methyl esters (FAMEs). Conversion efficiencies of soybean and palm oils to biodiesel over the as-prepared catalysts reached 97.0. ¡Ó. 3.0% and 95.4. ¡Ó. 3.7%, respectively, under optimal conditions. Activation energies of transesterification reactions of soybean and palm oils in excess methanol using these catalysts are 14.09. kJ/mol and 48.87. kJ/mol, respectively. ? 2012 Elsevier Ltd.

In this work, biodiesel production from catalyzed transesterification of triglycerides with excess methanol was studied by using ion-exchanged Zeolite Beta and MCM-22 as heterogeneous catalysts. Zeolite Beta and MCM-22 were synthesized with hydrothermal processes and, subsequently, modified by ion-exchanged with alkali ions. These as-obtained zeolite catalysts could yield a high conversion of triglycerides to biodiesel. The conversion efficiency was largely affected by crystallinity and frameworks of zeolite support, pH value of alkali ion-exchange solutions and alkali loadings onto the zeolite support. Furthermore, the effects of the duration of the sodium ion-exchange process on the final conversion efficiency of triolein to biodiesel, both the as-prepared Zeolite MCM-22 and Zeolite Beta catalysts were used. The effect of the duration of the sodium ion-exchange process is insignificant in transesterification using Na-ion-exchanged Zeolite MCM-22 catalysts from 0.5 to 4 h. In contrast, the conversion efficiency of triolein to biodiesel reached ca. 95% in 0.5 hours of transesterification using Zeolite Beta ion-exchanged with 3 mmol-eq. Na+/g cat for 0.5 hours. ? 2014 The Authors.

Human hepatocellular carcinoma (HCC) often arises from a background of liver cirrhosis. Therefore, in order to develop therapeutic strategies for HCC, an animal model bearing multifocal liver tumors accompanied by liver cirrhosis is a preferred experimental setting. In this study, we developed a rapid and reproducible method for generating such a model in rats by weekly administration of diethylnitrosamine (DEN) at doses based on body weight (BW). By adjusting the duration of administration of DEN, the animals could be induced to develop HCC alone, or HCC and liver cirrhosis simultaneously. The latter model was used for evaluating the therapeutic effects of adenoviral delivery of interferon-α (IFN-α). Our results demonstrated that targeting of IFN-α expression to the liver significantly reduced liver tumor volume and ameliorated liver cirrhosis. Mechanistic studies revealed that IFN-α gene therapy induced immunomodulatory, antiproliferative, and proapoptotic activities that were effective in the control of tumor growth, and reduced the expressions of transforming growth factor-β (TGF-β) and tissue inhibitor of metalloproteinase-1 (TIMP-1), leading to amelioration of liver cirrhosis. These results suggest that IFN-α gene therapy is a promising strategy to treat HCC patients who have concomitant liver cirrhosis.

In Taiwan, enterovirus 71 (EV71) has played an important role in severe enterovirus-related cases every year since the devastating outbreak in 1998. Three genogroups A, B, C occur worldwide; with the B and C genogroups being subdivided into B1-B4 and C1-C4 subgenogroups respectively. To understand the mutation of the EV71 genogroup in Taiwan before and after 1998, a total of 54 worldwide strains were studied including 41 Taiwanese strains obtained in 1986 and 1998-2004. A fragment of 207 bp of the VP4 region was amplified and sequenced. Genetic analysis was performed using MEGA software (version 3.0) for the nucleotide sequence alignment and phylogenetic analysis. In Taiwan, the subgenogroup B1 was predominant before 1998 while subgenogroup C2 was the major etiologic group in 1998 outbreak. A minor etiologic group outbreak in 1998, subgenogroup B4, became predominant during the period from 1999 to 2003. In this study, subgenogroup C4 emerged and became predominant in 2004 in Taiwan. The nucleotide differences between B1 and C2, C2 and B4, B4 and C4 were 20%-26%, 19%-27%, 18%-22%, respectively. Nucleotide sequence alignment revealed 67 substitutions. Most of the substitutions (62/67) were silent mutations. This is the first report about the emergence of EV71 subgenogroup C4 in Taiwan. ? 2005 Wiley-Liss, Inc.

This paper, a continuation of our previous work, is a presentation of the effect of the morphology and the average thickness of the deformed coating films on the slow diffusional release characteristics analyzed numerically under the constraints of the constant volume of the drug matrices and the coating films, if the films have the same average thickness. Increasing the average thickness of the coating films slows down the fractional release and the average release rate of the drug and smoothen the initial burst of the drug, as well as increase the initial lag time. The effect due to deformation of the coating films on these diffusional release characteristics are found to be less significant with the increasing average thickness of the coating films. Interestingly initial lag times are found to be the same for the coated particles having the same smallest thickness but different average thickness of coating films. The effect due to the change in the average thickness of the coating films on the characteristics of the slow controlled-release is discussed to shed light on the design of a better controlled-release device. ? 2002 Elsevier Science B.V. All rights reserved.

Lung cancer is a prevalent disease and is one of the leading causes of mortality worldwide. Despite the development of various anticancer drugs, the prognosis of lung cancer is relatively poor. Metastasis of lung cancer, as well as chemoresistance, is associated with a high mortality rate for patients with lung cancer. Camptothecin (CPT) is a well-known anticancer drug, which causes cancer cell apoptosis via the induction of DNA damage; however, the cytotoxicity of CPT easily reaches a plateau at a relatively high dose in lung cancer cells, thus limiting its efficacy. The present study demonstrated that CPT may induce autophagy in two human non-small cell lung cancer cell lines, H1299 and H460. In addition, the results of a viability assay and Annexin V staining revealed that CPT-induced autophagy could protect lung cancer cells from programmed cell death. Conversely, the cytotoxicity of CPT was increased when autophagy was blocked by 3-methyladenine treatment. Furthermore, inhibition of autophagy enhanced the levels of CPT-induced DNA damage in the lung cancer cell lines. Accordingly, these findings suggested that autophagy exerts a protective role in CPT-Treated lung cancer cells, and the combination of CPT with a specific inhibitor of autophagy may be considered a promising strategy for the future treatment of lung cancer. ? 2018 Spandidos Publications. All rights reserved.

Chemical hydride is one of the most potential hydrogen storage materials which can effectively increase hydrogen storage capacity. To meet the new goal of U.S. department of energy (DoE), 4.5wt% and 5.5 wt% of gravimetric hydrogen density capacity by 2010 and 2015, respectively, ammonia borane (AB) is an attractive material due to high intrinsic hydrogen density (i.e. 19.6 wt%). Such a high intrinsic hydrogen density increases the possibility to apply to be the on-board power source of vehicle system, not only for 3C electric product. In this study, hydrogen evolution from hydrolysis of ammonia borane in limiting water conditions is studied. The solid composite of ammonia borane hydrogen fuel is synthesized with pulverized catalyst through the high energy ball milling process. Various parameters such as the amount of water dosage, temperature, loading of catalysts, on hydrogen production characteristics will be discussed. Kinetic behavior of the hydrolysis reaction in such limiting water supply conditions will also be investigated. Based on experimental outcomes, optimal conditions on hydrogen production from this hydrogen storage system will be proposed.

Hydrogen, one of environmentally benign energies, has attracting more and more attention. Out of many hydrogen storage systems, chemical hydrides not only have a high hydrogen storage capacity, but also produce ultrapure hydrogen in presence of adequate catalysts at room temperature. Among many chemical hydrides, ammonia borane (NH3BH3) is one of the promising candidates because its intrinsic hydrogen content is as high as 19.6 wt%. Moreover, the spent products of ammonia borane are non-flammable and rarely toxic. The chemical hydride fuel system was prepared by pulverizing ammonia borane and Ni-Co/r-GO catalysts in a high-energy ball mill. The hydrogen was produced from catalyzed hydrolysis reaction of ammonia borane composite initiated with limited amount of water. Variable parameters such as the amount of water dosage and loading of catalysts will be discussed in this study. ? 2014 The Authors.

Type 1 diabetes is an autoimmune destruction of pancreatic islet beta cell disease, making it important to find a new alternative source of the islet beta cells to replace the damaged cells. hES (human embryonic stem) cells possess unlimited self-renewal and pluripotency and thus have the potential to provide an unlimited supply of different cell types for tissue replacement. The hES-T3 cells with normal female karyotype were first differentiated into EBs (embryoid bodies) and then induced to generate the T3pi (pancreatic islet-like cell clusters derived from T3 cells), which expressed pancreatic islet cell-specific markers of insulin, glucagon and somatostatin. The expression profiles of microRNAs and mRNAs from the T3pi were analysed and compared with those of undifferentiated hES-T3 cells and differentiated EBs. MicroRNAs negatively regulate the expression of protein-coding mRNAs. The T3pi showed very high expression of microRNAs, miR-186, miR-199a and miR-339, which down-regulated the expression of LIN28, PRDM1, CALB1, GCNT2, RBM47, PLEKHH1, RBPMS2 and PAK6. Therefore, these microRNAs and their target genes are very likely to play important regulatory roles in the development of pancreas and/or differentiation of islet cells, and they may be manipulated to increase the proportion of beta cells and insulin synthesis in the differentiated T3pi for cell therapy of type I diabetics. ? The Author(s) Journal compilation ? 2011 Portland Press Limited.

In this work microwave and reflux-assisted transesterification of triolein in methanol was carried out with alkaliloaded low-Al Zeolite Beta as catalyst. The results show that the alkali-T reated Zeolite Beta can effectively catalyze transesterification reaction of triglycerides to produce fatty acid ethyl esters (biodiesel), if Zeolite Beta has been properly modified with the alkali ion-exchange process. As a result, the final conversion yield over 90% could be obtained within an hour of reflux reaction. However, the durability of this Na-modified Zeolite Beta still has much room to be improved. In this work, this inferior catalytic durability is overcome by using the low-Al Zeolite Beta with a smaller particle size near 0.5μm. Consequently, for at least eight cycles, cyclic tests of these zeolite catalysts do not result in any significant decrease in catalysis in transesterification reaction. It is inferred that alkali cations existing in defect-sites of low-Al Zeolite Beta can be supplied to the surface of the catalysts during transesterification and enhance the catalysis. ? 2014 The Authors.

Inflammatory mediators such as TNF-α and interleukin (IL)-1β, and IL-8, which can enhance binding of low-density lipoprotein (LDL) to endothelium and upregulate expression of leukocyte adhesion molecules on endothelium during atherogenesis. Lycopene, a natural carotenoid from tomato and other sources, has been shown to prevent cardiovascular diseases in epidemiological studies. However, its anti-inflammatory action mechanism remains unclear. In the present study, we studied the effect of lycopene on TNF-α-induced signaling in human umbilical endothelial cells (HUVECs). We found that TNF-α-induced intercellular adhesion molecule-1 (ICAM-1) expression in HUVECs was inhibited by lycopene, whereas cyclooxygenase-2 (COX-2) and platelet-endothelial cell adhesion molecule (PECAM-1) expression were not affected. A further analysis indicated that lycopene attenuated TNF-α-induced IκB phosphorylation, NF-κB expression, and NF-κB p65 translocation from cytosol to nucleus. In line with this, TNF-α-induced NF-κB-DNA but not AP1-DNA complexes formation was inhibited by lycopene, as determined by the electrophoretic mobility shift assay (EMSA). On the other hand, lycopene did not affect TNF-α-induced p38 and extracellular matrix-regulated kinase1/2 (ERK1/2) phosphorylation and interferon-γ (IFN-γ)-induced signaling, suggesting that lycopene primarily affects TNF-α-induced NF-κB signaling pathway. In a functional study, lycopene dose-dependently attenuated monocyte adhesion to endothelial monolayer but not that adhesion to extracellular matrix. Taken together, we provided here the first evidence showing that lycopene is able to inhibit TNF-α-induced NF-κB activation, ICAM-1 expression, and monocyte-endothelial interaction, suggesting an anti-inflammatory role of lycopene and possibly explaining in part why lycopene can prevent cardiovascular diseases. ? 2008 Elsevier B.V. All rights reserved.

Optimization of esterification of palmitic acid in excess methanol by solid acid catalyst, viz. Amberlite? IR-120 (H) resin, is studied by combining backward stepwise regression technique with a 2 5-1 fractional factorial design. Optimum conditions are found as follows: 8:1 in the molar feed ratio of methanol to palmitic acid, a reaction temperature as 61.0 ¢XC, a reaction time of 10.5 h, catalyst loadings at 10 wt% of palmitic acid, and a stirring speed of 600 rpm. At this condition, conversion efficiency of palmitic acid to palmitic acid methyl ester reaction is near 98.9%.

Biodiesel was produced from transesterification of triolein with excess methanol using NaOH-treated kaolin clay as an active catalyst. The natural kaolin was first transformed into an efficacious catalyst under the conditions as (1) calcined kaolin/NaOH(aq ) = 1/2 (w/w), and (2) hydrothermal aging for 24 h at 90 ¢XC prior to calcination at 400 ¢XC for 6 h. Coincidently, these NaOH-treated kaolin catalysts possess characteristics of zeolite LTA. Subsequently, the Box¡VBehnken experimental design was applied to optimize the transesterification process of triolein in methanol. The optimal conditions are found as follows: (1) 36.6 as the mass ratio of methanol-to-triolein in the initial feed, (2) at 62.9 ¢XC as the reaction temperature, (3) 146 min for reaction time, and (4) a catalyst loading at 72 wt. % of triolein used. Under this optimal condition, the conversion efficiency of triolein to biodiesel is (92.8 ¡Ó 4.0)%. Furthermore, these as-synthesized zeolite LTA-kaolin catalysts could be reused at least for three consecutive reaction cycles. ? 2017 Taiwan Institute of Chemical Engineers

Optimization of sodium loading on zeolite HY for catalyzed transesterification of triolein in excess methanol to biodiesel was studied. Zeolite HY catalyst was activated by loading sodium ions to their surface via an ion-exchange method. The effects of ion-exchange process parameters, including the temperature, the process time, the pH value, as well as concentrations and sources of Na+ cations (NaOH, NaCl and Na2SO4), on the conversion yield of triolein to biodiesel were investigated. Most of these Na+-activated zeolite HY catalysts could really facilitate the catalyzed transesterification reaction of triolein to biodiesel at a lower temperature near 65¢XC. Consequently, a high conversion yield of triglycerides to biodiesel at 97.3% was obtained at 65¢XC. Moreover, the durability of zeolite catalysts was examined as well. Catalytic performance tests of these zeolite catalysts in transesterification did not show a significant decrease in catalysis at least for three batch cycles. ? 2013 Elsevier Ltd.

The rheological characteristics of the wastewater sludge were investigated by using a Haake Rheostress RS 75 rheometer. The shear creep compliance experiments and the dynamic viscosity measurements were conducted. The shear creep compliance experiments indicate the addition of polymer coagulants to the sludge samples will form more rigid structures. The elastic solid-like behaviors were always observed in the samples with polymers. The Voigt model was successfully employed in modeling the viscoelastic retardation behavior of sludge samples in the shear creep compliance tests. Moreover, the dynamic viscosity curves of the sludge samples with/without polymer could be described by the power law model of Ostwald and de Waele at the medium shear rates, ca. 100-300 s-1. Consequently, addition of polymer to the sludge tends to extend the applicable ranges of the shear rates for the power law model as well as to decrease the power law index.

The effects of the morphology and drug diffusivity in the coating film on the slow release characteristics have been analyzed numerically under the constraint that the volume of the coating film and the drug matrix is maintained constant. Two different systems of coated particles with deformed coating films were studied and their release characteristics compared with those of the coated particles having spherical coating films. The average release rate, fractional release, drug concentration profiles, and the initial burst of drug were found to be strongly influenced by the ratio of drug diffusivity in the coating film to that in the drug matrix Dr (i.e., dimensionless drug diffusivity in the coating film). Increasing Dr always increased the release rate, the fractional release, and the initial burst of drug, but reduced the initial lag times of drug release. The effect of shape deformation was very significant in the drug concentration profiles and the initial lag times; in contrast, it was not so substantial on the fractional release and the average release rates. The morphology difference in the deformed systems was also found to affect the release characteristics to different extents. Increasing the degree of the shape deformation, represented by the perturbation parameter £`, always reduced the effective surface area for the controlled release of drug. Because of the compensation effects between decreasing surface area and the non-uniform mass flux distribution, even though the heterogeneity of surface mass flux distribution would become more considerable, the effects of increasing shape deformation to the overall release rate would be less than expected unless the coating film was deformed significantly enough. The effect of the shape deformation and the morphology difference become less effective to differentiate the release characteristics with increasing Dr. ? 2001 Wiley-Liss, Inc.