Browsing by Author "Chen, Pei-Chung"

Now showing 1 - 9 of 9

Chemical structures of extra- and intra-cellular algogenic organic matters as precursors to the formation of carbonaceous disinfection byproducts
(2017-11-15)
Hua, Lap-Cuong
;
Lin, Jr-Lin
;
Chen, Pei-Chung
;
Huang, Chihpin
;
環境工程研究所
Algal eutrophication in reservoirs is frequently accompanied by a remarkable increase in the concentration of algogenic organic matter (AOM). Because AOM is well-known as an important precursor to disinfection by-products (DBPs) in drinking water, algal eutrophication poses severe concerns for public health. This study aimed to characterize the chemical properties of AOM from two major origins, i.e. extra-(EOM) and intracellular organic matter (IOM), of a commonly found green alga Chlorella sp. as precursors to trihalomethanes (THMs) and haloacetic acids (HAAs). Particularly, the corresponding relation between the chemical functional structure of EOM and IOM and their THM and HAA formation potential (THMFP and HAAFP) was comprehensively investigated. Results show that IOM chiefly comprised of aromatic and other aliphatic protein-like materials (high organic nitrogen content) those have high activity for chlorine substitution (high UV253/UV203 value) due to the high hydroxyl and amide contents in its chemical structures. EOM alternatively exhibited the characteristics of humic-and fulvic-like materials accompanying with high DOC/DON ratio and aromaticity. However, the chemical structure of EOM had a low tendency for chlorine substitution (low UV253/UV203 value); it was also accompanied by a considerable content of carboxylic moisture, which likely resulted in an unfavorable substitution reaction of EOM with chlorine. As a result, the carbonaceous DBP formation potential (C-DBPFP) showed that IOM yielded higher levels of both THMFP and HAAFP than that yielded by EOM.
Effects of C/N ratio on nitrate removal and floc morphology of autohydrogenotrophic bacteria in a nitrate-containing wastewater treatment process
(2018-07-01)
Tran Ngoc Phu Nguyen
;
Chao, Shu-Ju
;
Chen, Pei-Chung
;
Huang, Chihpin
;
環境工程研究所
The effects of C/N ratio of a nitrate-containing wastewater on nitrate removal performed by autohydrogenotrophic bacteria as well as on the morphological parameters of floc such as floc morphology, floc number distribution, mean particle size (MPS), aspect ratio and transparency were examined in this study. The results showed that the nitrate reduction rate increased with increasing C/N ratio from 0.5 to 10 and that the nitrogen removal of up to 95% was found at the C/N ratios of higher than 5 (between 0.5-10). Besides, high C/N ratio values reflected a corresponding high nitrite accumulation after 12-hr operation, and a fast decreasing rate of nitrite in the rest of operational time. The final pH values increased with the C/N ratio increasing from 0.5 to 2.5, but decreased with the C/N ratio increasing from 2.5 to 10. There were no significant changes in floc morphology with the MPSs ranging from 35 to 40 mu m. Small and medium-sized flocs were dominant in the sludge suspension, and the number of flocs increased with the increasing C/N ratios. Furthermore, the highest apparent frequency of 10% was observed at aspect ratios of 0.5 and 0.6, while the transparency of flocs changed from 0.1 to 0.7. (C) 2017 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V.
Effects of electro-coagulation on fouling mitigation and sludge characteristics in a coagulation-assisted membrane bioreactor
(2015-12-01)
Hua, Lap-Cuong
;
Huang, Chihpin
;
Su, Yu-Chun
;
Tran-Ngoc-Phu Nguyen
;
Chen, Pei-Chung
Although much research effort has focused on methods to mitigate fouling of membrane bioreactors (MBRs), fouling is still inevitable. This paper aims to corroborate the roles of electro-coagulation approach within a coagulation-assisted MBR, termed electro-MBR. The effects of electro-coagulation on sludge characteristics and fouling behavior were investigated. A batch-scale experiment was carried out to identify an optimum electric current condition for electro-MBR study, in which the electro-MBR and a traditional MBR were identically set for numerous comparisons. The average fouling rate was substantially reduced 7.8 fold resulting in no chemical cleaning requirements during the entire operation of the electro-MBR. Enhanced sludge compressibility and controlled growth of filamentous bacteria positively affected by electro-coagulation were also obtained in the electro-MBR. This paper suggests that fouling mitigation in electro-MBR can be attributed to two mechanisms; (i) charge neutralization and adsorption for soluble foulants; (ii) electro-chemical oxidation for bound foulants. Furthermore, we conclude that electro-coagulation can simultaneously alter morphology and microbial structure of sludge flocs to become more compressible with lower fouling tendency, which would be beneficial for the mitigation of membrane fouling in electro-MBR. (C) 2015 Elsevier B.V. All rights reserved.
Effects of Selenium Yeast on Oxidative Stress, Growth Inhibition, and Apoptosis in Human Breast Cancer Cells
(2015-01-01)
Guo, Chih-Hung
;
Hsia, Simon
;
Shih, Min-Yi
;
Hsieh, Fang-Chin
;
Chen, Pei-Chung
Recent evidence suggests that selenium (Se) yeast may exhibit potential anti-cancer properties; whereas the precise mechanisms remain unknown. The present study was aimed at evaluating the effects of Se yeast on oxidative stress, growth inhibition, and apoptosis in human breast cancer cells. Treatments of ER-positive MCF-7 and triple-negative MDA-MB-231 cells with Se yeast (100, 750, and 1500 ng Se/mL), methylseleninic acid (MSA, 1500 ng Se/mL), or methylselenocysteine (MSC, 1500 ng Se/mL) at a time course experiment (at 24, 48, 72, and 96 h) were analyzed. Se yeast inhibited the growth of these cancer cells in a dose- and time-dependent manner. Compared with the same level of MSA, cancer cells exposure to Se yeast exhibited a lower growth-inhibitory response. The latter has also lower superoxide production and reduced antioxidant enzyme activities. Furthermore, MSA (1500 ng Se/mL)-exposed non-tumorigenic human mammary epithelial cells (HMEC) have a significant growth inhibitory effect, but not Se yeast and MSC. Compared with MSA, Se yeast resulted in a greater increase in the early apoptosis in MCF-7 cells as well as a lower proportion of early and late apoptosis in MDA-MB-231 cells. In addition, nuclear morphological changes and loss of mitochondrial membrane potential were observed. In conclusion, a dose of 100 to 1500 ng Se/mL of Se yeast can increase oxidative stress, and stimulate growth inhibitory effects and apoptosis induction in breast cancer cell lines, but does not affect non-tumorigenic cells.
Nitrate removal and extracellular polymeric substances of autohydrogenotrophic bacteria under various pH and hydrogen flow rates
(2018-01-01)
Tran-Ngoc-Phu Nguyen
;
Chen, Pei-Chung
;
Huang, Chihpin
;
環境工程研究所
;
Institute of Environmental Engineering
In recent years there has been an increasing interest in the use of autohydrogenotrophic bacteria to treat nitrate from wastewater. However, our knowledge about the characteristics of extracellular polymeric substances (EPS) releasing by these activities is not yet very advanced. This study aimed to investigate the change in EPS compositions under various pH values and hydrogen flow rates, taking into consideration nitrogen removal. Results showed that pH 7.5 and a hydrogen flow rate of 90 mL/min were the optimal operating conditions, resulting in 100% nitrogen removal after 6 hr of operation. Soluble and bound polysaccharides decreased, while bound proteins increased with increasing pH. Polysaccharides increased with increasing hydrogen flow rate. No significant change of bound proteins was observed at various hydrogen flow rates. (C) 2017 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V.
Optical properties of algogenic organic matter within the growth period of Chlorella sp and predicting their disinfection by-product formation
(2018-04-15)
Hua, Lap-Cuong
;
Lin, Jr-Lin
;
Syue, Ming-Yang
;
Huang, Chihpin
;
Chen, Pei-Chung
Algogenic organic matter (AOM) in eutrophic waters is a well-known precursor to disinfection by-product (DBP) formation in drinking water. This purpose of this study is (i) to characterize the optical properties of AOM origins, including intra- (IOM) and extra-cellular organic matter (EOM), derived from Chlorella sp. growth as precursors to two major carbonaceous DBPs (C-DBPs), trihalomethanes (THMs) and haloacetic acids (HAAs) and (ii) to correlate these optical properties with THM and HAA formation potential (FP) in order to predict DBP formation. The results show that both EOM and IOM had low UV254 and UV280 absorbance during their entire growth phase. While IOM chiefly comprised of aromatic proteins and soluble microbial products-like substances (80% of average fluorescent intensity-AFI), EOM spectra were rich in humic- and fulvic-like substances (60% AFI). However, its chemical nature likely differed from terrestrial humics. In DBPFP tests, IOM was a higher-yielding precursor of THMs and HAAs compared to EOM, regardless its growth status. Consequently, C-DBPFP of IOM was always higher than EOM during four growth phases. Results from DBP tests also showed insignificant variation of EOM-derived THMFP and HAAFP during the algal growth phase, while the algal growth status strongly influenced the yields of IOM-derived THMFP and HAAFP. From correlation analysis, our results showed no correlation between UV absorbance with THMFP and HAAFP. Conversely, the regional AFI showed a good correlation with HAAFP and C-DBPFP. Predicting models based on AFI for the formation of HAAs and C-DBPs consequently yielded great predictability for laboratory AOM-containing water samples, with a coefficient of determination R-2 = 0.879, p < 0.01 and R-2 = 0.846, p < 0.01. This study indicates a promising application of fluorescent spectra for predicting DBPs derived from algae-rich water sources. (c) 2017 Elsevier B.V. All rights reserved.
Supplementation with Selenium yeast on the prooxidant-antioxidant activities and anti-tumor effects in breast tumor xenograft-bearing mice
(2015-12-01)
Guo, Chih-Hung
;
Hsia, Simon
;
Hsiung, Der-Yun
;
Chen, Pei-Chung
;
工學院
Selenium (Se) is essential for antioxidant activity involved in immune function and anti-carcinogenic action, whereas at higher concentrations, Se may have pro-oxidant properties. The present study was aimed at determining the effects of Se supplementation, as Se yeast, on oxidative stress in non-tumor/tumor tissues, as well as regulation of the apoptotic process, and immune responses in mice-bearing breast tumor xenografts. Female BALB/cByJNarl mice were divided into control (CNL and CNL-con), Se-supplemented control (CNL-HS, given as a single oral dose of 912 ng Se daily), breast tumor-bearing (TB and TB-con), TB-LS (228 ng Se), TB-MS (456 ng Se) and TB-HS (912 ng Se) groups. All mice were treated with/without Se for 14 days. A number of variables were further measured. Compared with the TB groups, tumor bearing mice with Se supplement had increased plasma Se concentrations, reduced erythrocyte Se-dependent glutathione peroxidase (GPx) activity and malondialdehyde (MDA) products and inhibited tumor growth. They have also higher Se concentrations in non-tumor and tumor tissues. Significantly elevated concentrations of MDA and reduced GPx activities, as well as increased anti-apoptotic bcl-2 and tumor suppressor p53 concentrations in tumor tissues were observed as Se accumulated in tumor, whereas lower MDA products were found in various non-tumor tissues than did the corresponding values. Further, there were elevated concentrations of Th1-derived cytokines and decreased Th2-type interleukin (IL)-4 in tumor-bearing mice with the treatment of Se. In conclusion, accumulation of Se in tumors may induce oxidative stress and p53-dependent pro-oxidative apoptosis, thus inhibiting the growth of breast tumor. (C) 2015 Elsevier Inc. All rights reserved.
Teratogenic responses of zebrafish embryos to decabromodiphenyl ether (BDE-209) in the presence of nano-SiO2 particles
(2017-07-01)
Chao, Shu-Ju
;
Huang, Chin Pao
;
Chen, Pei-Chung
;
Huang, Chihpin
;
環境工程研究所
This study investigated the influence of nano-SiO2 particles (nSiO(2)) on the teratogenic responses of zebrafish embryos to decabromodiphenyl ether (BDE-209). Zebrafish embryos were exposed to BDE-209 in the absence and presence of nSiO(2) for 96 h post fertilization (hpf). Results showed that formation of nSiO(2)-BDE-209 associates promoted both extracellular and intracellular uptake of BDE-209 by zebrafish embryos, thereby increasing the bioconcentration of BDE-209 on the chorion surface and the embryos. Results also showed embryos delay hatching temporarily when co-exposure to BDE-209 and nSiO(2) at 60 hpf. Furthermore, there was heartbeat decline (28.3 beats/10s) and increase in irregular heartbeat (45.8%) in zebrafish larvae at 96 hpf, compared to the sole exposure to BDE-209 (32.7 beats/10s and 0%). Malformation in terms of spinal curvature (SC), pericardial edema (PE) and yolk sac edema (YSE) were observed on zebrafish larvae at 33.9, 23.4, and 18%, respectively. Overall, abnormal development of zebrafish was apparent when co-exposure to BDE-209 and nSiO(2). All relevant evidence considered, nSiO(2) could facilitate the transport of BDE-209 towards zebrafish embryos and negatively impact the development of zebrafish. (C) 2017 Elsevier Ltd. All rights reserved.
Uptake of BDE-209 on zebrafish embryos as affected by SiO2 nanoparticles
(2018-08-01)
Chao, Shu-Ju
;
Huang, C. P.
;
Chen, Pei-Chung
;
Chang, Shih-Hsien
;
Huang, Chihpin
It was hypothesized that interactions between emerging contaminants such as decabromodiphenyl ether (BDE-209) and nanoparticles (NPs) such as nano-SiO2 (nSiO(2)), can affect contaminant transport in the aquatic environment and its ecotoxicity. This study assessed the influence of nSiO(2) on the uptake of BDE-209 by zebrafish embryo. The distribution of BDE-209 and nSiO(2) on the external chorion and the internal embryo mass (i.e., dechorionated embryo) was measured. For single exposure of nSiO(2) to zebrafish embryo, separately, results showed that nSiO(2) accumulation on the chorion surface was higher than that in the dechorionated embryo. The nSiO(2) accumulation on the chorion surface was 129-200 mg-nSiO(2)/gchorion at 48 h post fertilization, hpf, of exposure time, whereas the equilibrium adsorption of nSiO(2) on the dechorionated embryo was ca. 0.42-0.54 mg-nSiO(2)/g-embryo at 6 hpf. Results showed that the formation of nSiO(2)-BDE-209 associates promoted both extracellular and intracellular uptake of BDE-209 by zebrafish embryo, thereby increasing the bioconcentration of BDE-209 on the chorion surface and in embryo. The results also revealed that the accumulation of BDE-209 on the chorion was remarkably greater than that on the dechorionated embryo at 48 hpf. The uptake of BDE-209 was 17.2 +/- 0.45 mg/g-chorion (or 86 ng-BDE-209/chorionated embryo) and 0.37 +/- 0.01 mg/g-embryo (or 18.6 ng-BDE-209/dechorionated embryo), respectively, when co-exposure of zebrafish embryos to BDE-209 and nSiO(2). Results from the SEM and EDS analysis revealed that nSiO(2) already passed through the chorion and adhered to the embryo surface/mass. (C) 2018 Elsevier Ltd. All rights reserved.