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Traditionally, direct‐reading instruments have been used to directly determine the concentrations of indoor air pollutants that may exceed the regulation limits. However, these instruments cannot directly assess the potential health hazards of these pollutants to humans. In this study, we developed and improved a bacterial reverse mutation assay (Ames test) by using a direct gas exposure module to directly determine the mutagenicity of indoor air quality using five tester bacterial strains (TA98, TA100, TA102, TA1535, and TA1537). Thereafter, the module was used to evaluate the effects of exposure time, different concentrations of HCHO or toluene, and mutagenic activities. We found that TA100 was the most sensitive strain and was reverted by relatively lower concentrations of 0.035 ppm HCHO. Furthermore, 50 ppm of toluene exposures caused a significant increase in the number of revertant colonies of TA100 without S9 activation at the 1.5–8‐h exposure time intervals. Our findings provide new evidence that gaseous HCHO exposure could display weak but direct, time‐dependent, and dose‐dependent mutagenic activities. The weak, direct‐acting, indirect‐acting, and time‐dependent mutagen of 50 ppm toluene was also confirmed. Moreover, our improved Ames module and the exposure conditions provided in this study can be further applied to evaluate the mutagenicity of indoor air quality.
Po‐Wen Chen; Tai‐Chen Kuo; Zhen‐Shu Liu; Hung‐Fu Lu. Assessment of the mutagenicity of two common indoor air pollutants, formaldehyde and toluene. Indoor Air 2021, 31, 1353 -1363.
AMA StylePo‐Wen Chen, Tai‐Chen Kuo, Zhen‐Shu Liu, Hung‐Fu Lu. Assessment of the mutagenicity of two common indoor air pollutants, formaldehyde and toluene. Indoor Air. 2021; 31 (5):1353-1363.
Chicago/Turabian StylePo‐Wen Chen; Tai‐Chen Kuo; Zhen‐Shu Liu; Hung‐Fu Lu. 2021. "Assessment of the mutagenicity of two common indoor air pollutants, formaldehyde and toluene." Indoor Air 31, no. 5: 1353-1363.
Lactoferrin (LF) is a multifunctional protein found in mammals, and it shows broad-spectrum antimicrobial activity. To improve the functional properties of specific probiotics in order to provide both the beneficial characteristics of lactic acid bacteria and the biological activity of LF, cDNAs of bovine LF (BLF), human LF (HLF), or porcine LF (PLF) were cloned into a nisin-inducible plasmid. These were then transformed into the selected eight probiotics, which are LF-resistant hosts. Expression of recombinant LFs (rLFs) was analyzed via SDS-PAGE and Western blot analysis. Although the selected host strains may not contain the nisRK genes (NisK, the sensor kinase; NisR, the regulator protein), the components of autoregulation, a low level of LFs expression can be successfully induced by using nisin within bacterial cells in a time-dependent manner in three engineered clones, including Lactobacillus delbrueckii/HLF, L. delbrueckii/BLF, and L. gasseri/BLF. Lactobacillus delbrueckii and Lactobacillus gasseri originate from yogurt and human milk, respectively, and both strains are functional probiotic strains. Therefore, we further compared the antibacterial activities of disrupted recombinant probiotic clones, conventional strains (host control), and vector control ones by using agar diffusion and broth inhibition analysis, and the expression of rLFs in the above three clones considerately improved their antibacterial efficacies against four important food-borne pathogens, namely, Escherichia coli, Staphylococcus aureus, Enterococcus faecalis, and Salmonellaenterica. In conclusion, this study provides a simple strategy for the production of functional LFs (BLF and HLF) in both functional and LF-resistant hosts for applications in the field.
Zhen-Shu Liu; Chuen-Fu Lin; Chung-Pei Lee; Min-Chi Hsieh; Hung-Fu Lu; Ying-Fang Chen; Yu-We Ku; Po-Wen Chen. A Single Plasmid of Nisin-Controlled Bovine and Human Lactoferrin Expressing Elevated Antibacterial Activity of Lactoferrin-Resistant Probiotic Strains. Antibiotics 2021, 10, 120 .
AMA StyleZhen-Shu Liu, Chuen-Fu Lin, Chung-Pei Lee, Min-Chi Hsieh, Hung-Fu Lu, Ying-Fang Chen, Yu-We Ku, Po-Wen Chen. A Single Plasmid of Nisin-Controlled Bovine and Human Lactoferrin Expressing Elevated Antibacterial Activity of Lactoferrin-Resistant Probiotic Strains. Antibiotics. 2021; 10 (2):120.
Chicago/Turabian StyleZhen-Shu Liu; Chuen-Fu Lin; Chung-Pei Lee; Min-Chi Hsieh; Hung-Fu Lu; Ying-Fang Chen; Yu-We Ku; Po-Wen Chen. 2021. "A Single Plasmid of Nisin-Controlled Bovine and Human Lactoferrin Expressing Elevated Antibacterial Activity of Lactoferrin-Resistant Probiotic Strains." Antibiotics 10, no. 2: 120.
Zhen-Shu Liu; Hai-Ming Lan. Synthesis of Mesoporous Silica Materials from Incineration Bottom Ash for the Removal of Toluene. International Journal of Environmental Science and Development 2019, 10, 96 -99.
AMA StyleZhen-Shu Liu, Hai-Ming Lan. Synthesis of Mesoporous Silica Materials from Incineration Bottom Ash for the Removal of Toluene. International Journal of Environmental Science and Development. 2019; 10 (3):96-99.
Chicago/Turabian StyleZhen-Shu Liu; Hai-Ming Lan. 2019. "Synthesis of Mesoporous Silica Materials from Incineration Bottom Ash for the Removal of Toluene." International Journal of Environmental Science and Development 10, no. 3: 96-99.
Two incinerators in Taiwan have recently attempted to reuse the fly and bottom ash that they produce, but the mutagenicity of these types of ash has not yet been assessed. Therefore, we evaluated the mutagenicity of the ash with the Ames mutagenicity assay using the TA98, TA100, and TA1535 bacterial strains. We obtained three leachates from three leachants of varying pH values using the toxicity characteristic leaching procedure test recommended by the Taiwan Environmental Protection Agency (Taiwan EPA). We then performed the Ames assay on the harvested leachates. To evaluate the possible relationship between the presence of heavy metals and mutagenicity, the concentrations of five heavy metals (Cd, Cr, Cu, Pb, and Zn) in the leachates were also determined. The concentrations of Cd and Cr in the most acidic leachate from the precipitator fly ash and the Cd concentration in the most acidic leachate from the boiler fly ash exceeded the recommended limits. Notably, none of the nine leachates extracted from the boiler, precipitator, or bottom ashes displayed mutagenic activity. This data partially affirms the safety of the fly and bottom ash produced by certain incinerators. Therefore, the biotoxicity of leachates from recycled ash should be routinely monitored before reusing the ash.
Po-Wen Chen; Zhen-Shu Liu; Min-Jie Wun; Tai-Chen Kuo. Cellular Mutagenicity and Heavy Metal Concentrations of Leachates Extracted from the Fly and Bottom Ash Derived from Municipal Solid Waste Incineration. International Journal of Environmental Research and Public Health 2016, 13, 1078 .
AMA StylePo-Wen Chen, Zhen-Shu Liu, Min-Jie Wun, Tai-Chen Kuo. Cellular Mutagenicity and Heavy Metal Concentrations of Leachates Extracted from the Fly and Bottom Ash Derived from Municipal Solid Waste Incineration. International Journal of Environmental Research and Public Health. 2016; 13 (11):1078.
Chicago/Turabian StylePo-Wen Chen; Zhen-Shu Liu; Min-Jie Wun; Tai-Chen Kuo. 2016. "Cellular Mutagenicity and Heavy Metal Concentrations of Leachates Extracted from the Fly and Bottom Ash Derived from Municipal Solid Waste Incineration." International Journal of Environmental Research and Public Health 13, no. 11: 1078.
The mutagenic potential of leachates derived from the bottom ash of a municipal solid waste incinerator in Taiwan were evaluated using an Ames Salmonella mutagenicity assay with three standard tester strains, TA98, TA100, and TA1535. Three types of leachants, leachant A (pH 4.93), leachant B (pH 2.88), and leachant C (deionized water, pH 6.0), were carried out according to toxicity characteristic leaching procedure (TCLP). Moreover, two types of bottom ash, nonsieved and sieved bottom ash (particle size <4.75 mm), were analyzed with the TCLP and the Ames assay. The concentrations of five heavy metals (Cd, Cr, Cu, Pb, and Zn) in the leachates were also estimated with an ICP-OES. The results indicated that the metal concentrations in the TCLP leachates of bottom ash were all below the limits set by Taiwanese regulations. However, leachate A from nonsieved and <4.75-mm-sieved bottom ash showed mutagenicity. Moreover, leachate A from <4.75 mm-sieved bottom ash displayed stronger mutagenicity than that from nonsieved ash. The leachate A from <4.75-mm-sieved bottom ash, that were diluted by 100-fold showed no mutagenicity. In conclusion, our results suggested that the chemical composition and mutagenic potential of leachates should be monitored to evaluate the safety of bottom ash.
Po-Wen Chen; Zhen-Shu Liu; Min-Jie Wun; Cai-Ling Ran. Evaluating the mutagenicity of leachates obtained from the bottom ash of a municipal solid waste incinerator by using a Salmonella reverse mutation assay. Chemosphere 2015, 124, 70 -76.
AMA StylePo-Wen Chen, Zhen-Shu Liu, Min-Jie Wun, Cai-Ling Ran. Evaluating the mutagenicity of leachates obtained from the bottom ash of a municipal solid waste incinerator by using a Salmonella reverse mutation assay. Chemosphere. 2015; 124 ():70-76.
Chicago/Turabian StylePo-Wen Chen; Zhen-Shu Liu; Min-Jie Wun; Cai-Ling Ran. 2015. "Evaluating the mutagenicity of leachates obtained from the bottom ash of a municipal solid waste incinerator by using a Salmonella reverse mutation assay." Chemosphere 124, no. : 70-76.
Zhen-Shu Liu; Yu-Hui Peng; Chun-Yi Huang; Ming-Jui Hung. Application of thermogravimetry and differential scanning calorimetry for the evaluation of CO2 adsorption on chemically modified adsorbents. Thermochimica Acta 2015, 602, 8 -14.
AMA StyleZhen-Shu Liu, Yu-Hui Peng, Chun-Yi Huang, Ming-Jui Hung. Application of thermogravimetry and differential scanning calorimetry for the evaluation of CO2 adsorption on chemically modified adsorbents. Thermochimica Acta. 2015; 602 ():8-14.
Chicago/Turabian StyleZhen-Shu Liu; Yu-Hui Peng; Chun-Yi Huang; Ming-Jui Hung. 2015. "Application of thermogravimetry and differential scanning calorimetry for the evaluation of CO2 adsorption on chemically modified adsorbents." Thermochimica Acta 602, no. : 8-14.
Incineration flue gas contains polycyclic aromatic hydrocarbons (PAHs) and sulfur dioxide (SO2). The effects of SO2 concentration (0, 350, 750, and 1000 ppm), reaction temperature (160, 200, and 280 °C), and the type of activated carbon fibers (ACFs) on the removal of SO2 and PAHs by ACFs were examined in this study. A fluidized bed incinerator was used to simulate practical incineration flue gas. It was found that the presence of SO2 in the incineration flue gas could drastically decrease removal of PAHs because of competitive adsorption. The effect of rise in the reaction temperature from 160 to 280 °C on removal of PAHs was greater than that on SO2 removal at an SO2 concentration of 750 ppm. Among the three ACFs studied, ACF-B, with the highest microporous volume, highest O content, and the tightest structure, was the best adsorbent for removing SO2 and PAHs when these gases coexisted in the incineration flue gas.
Zhen-Shu Liu; Wen-Kai Li; Ming-Jui Hung. Simultaneous removal of sulfur dioxide and polycyclic aromatic hydrocarbons from incineration flue gas using activated carbon fibers. Journal of the Air & Waste Management Association 2014, 64, 1038 -1044.
AMA StyleZhen-Shu Liu, Wen-Kai Li, Ming-Jui Hung. Simultaneous removal of sulfur dioxide and polycyclic aromatic hydrocarbons from incineration flue gas using activated carbon fibers. Journal of the Air & Waste Management Association. 2014; 64 (9):1038-1044.
Chicago/Turabian StyleZhen-Shu Liu; Wen-Kai Li; Ming-Jui Hung. 2014. "Simultaneous removal of sulfur dioxide and polycyclic aromatic hydrocarbons from incineration flue gas using activated carbon fibers." Journal of the Air & Waste Management Association 64, no. 9: 1038-1044.
Incinerator bottom ash contains a large amount of silica and can hence be used as a silica source for the synthesis of mesoporous silica materials. In this study, the conditions for alkaline fusion to extract silica from incinerator bottom ash were investigated, and the resulting supernatant solution was used as the silica source for synthesizing mesoporous silica materials. The physical and chemical characteristics of the mesoporous silica materials were analyzed using BET, XRD, FTIR, SEM, and solid-state NMR. The results indicated that the BET surface area and pore size distribution of the synthesized silica materials were 992 m2/g and 2-3.8 nm, respectively. The XRD patterns showed that the synthesized materials exhibited a hexagonal pore structure with a smaller order. The NMR spectra of the synthesized materials exhibited three peaks, corresponding to Q(2) [Si(OSi)2(OH)2], Q(3) [Si(OSi)3(OH)], and Q(4) [Si(OSi)4]. The FTIR spectra confirmed the existence of a surface hydroxyl group and the occurrence of symmetric Si-O stretching. Thus, mesoporous silica was successfully synthesized from incinerator bottom ash. Finally, the effectiveness of the synthesized silica in removing heavy metals (Pb2+, Cu2+, Cd2+, and Cr2+) from aqueous solutions was also determined. The results showed that the silica materials synthesized from incinerator bottom ash have potential for use as an adsorbent for the removal of heavy metals from aqueous solutions.
Zhen-Shu Liu; Wen-Kai Li; Chun-Yi Huang. Synthesis of mesoporous silica materials from municipal solid waste incinerator bottom ash. Waste Management 2014, 34, 893 -900.
AMA StyleZhen-Shu Liu, Wen-Kai Li, Chun-Yi Huang. Synthesis of mesoporous silica materials from municipal solid waste incinerator bottom ash. Waste Management. 2014; 34 (5):893-900.
Chicago/Turabian StyleZhen-Shu Liu; Wen-Kai Li; Chun-Yi Huang. 2014. "Synthesis of mesoporous silica materials from municipal solid waste incinerator bottom ash." Waste Management 34, no. 5: 893-900.
Few studies have investigated the use of activated carbon fibres (ACFs) impregnated with metal oxides for the catalytic oxidation of volatile organic compounds (VOCs). Thus, the effects of the ACF-supported metal oxides on toluene removal are determined in this study. Three catalysts, namely, Ce, Mn, and Cu, two pretreatment solutions NaOH and H2O2, and three reaction temperatures of 250 degrees C, 300 degrees C, and 350 degrees C, were employed to determine toluene removal. The composition and morphology of the catalysts were analysed using Brunauer-Emmett-Teller (BET), transmission electron microscope (TEM), inductively coupled plasma (ICP), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectrometer (FTIR), and thermo-gravimetric analyser (TGA) to study the effects of the catalyst's characteristics on toluene removal. The results demonstrated that the metal catalysts supported on the ACFs could significantly increase toluene removal. The Mn/ACFs and Cu/ACFs were observed to be most active in toluene removal at a reaction temperature of 250 degrees C with 10% oxygen content. Moreover, the data also indicated that toluene removal was slightly improved after pretreating the ACFs with NaOH and H2O2. The results suggested that surface-metal loading and the surface characteristics of the ACFs were the determinant parameters for toluene removal. Furthermore, the removal of toluene over Mn/ACFs-H202 decreased when the reaction temperature considered was > 300 degrees C.
Zhen-Shu Liu; Yu-Hui Peng; Wen-Kai Li. Effects of activated carbon fibre-supported metal oxide characteristics on toluene removal. Environmental Technology 2014, 35, 1499 -1507.
AMA StyleZhen-Shu Liu, Yu-Hui Peng, Wen-Kai Li. Effects of activated carbon fibre-supported metal oxide characteristics on toluene removal. Environmental Technology. 2014; 35 (12):1499-1507.
Chicago/Turabian StyleZhen-Shu Liu; Yu-Hui Peng; Wen-Kai Li. 2014. "Effects of activated carbon fibre-supported metal oxide characteristics on toluene removal." Environmental Technology 35, no. 12: 1499-1507.
Few studies have investigated the use of activated carbon fibers (ACFs) impregnated with noble metals for the catalytic oxidation of volatile organic compounds (VOCs). This study determined the removal efficiency of toluene as a function of time over ACF-supported metal catalysts. Two catalysts (Pt and Pd), five reaction temperatures (120, 150, 200, 250, and 300 °C), and three oxygen contents (6%, 10%, and 21%) were investigated to determine the removal of toluene. To study the effects of the characteristics of the catalysts on toluene removal, the composition and morphology of the ACFs were analyzed using the BET, XPS, ICP, and FE-SEM. The results showed that the 0.42%Pd/ACFs showed greater activity for toluene removal than did 2.68%Pt/ACFs at a reaction temperature of 200 °C and an oxygen content of 10%. The main removal mechanism of toluene over the 2.68%Pt/ACFs at reaction temperatures less than 200 °C was adsorption. The long-term catalytic activity of the 2.68%Pt/ACFs for toluene removal at a reaction temperature of 250 °C and an oxygen content of 10% could be obtained. Furthermore, toluene removal over the 2.68%Pt/ACFs at 200 °C could be enhanced with increasing oxygen content.
Zhen-Shu Liu; Jian-Yuan Chen; Yu-Hui Peng. Activated carbon fibers impregnated with Pd and Pt catalysts for toluene removal. Journal of Hazardous Materials 2013, 256-257, 49 -55.
AMA StyleZhen-Shu Liu, Jian-Yuan Chen, Yu-Hui Peng. Activated carbon fibers impregnated with Pd and Pt catalysts for toluene removal. Journal of Hazardous Materials. 2013; 256-257 ():49-55.
Chicago/Turabian StyleZhen-Shu Liu; Jian-Yuan Chen; Yu-Hui Peng. 2013. "Activated carbon fibers impregnated with Pd and Pt catalysts for toluene removal." Journal of Hazardous Materials 256-257, no. : 49-55.
Many of the factors influencing the adsorption of volatile organic compounds by activated carbon fibers (ACFs) have been widely studied. However, most of them were investigated at low concentrations (500 ppm or less) and at low adsorption temperatures (lower than 100 °C). This study was to determine simultaneously the oxidation and adsorption of toluene onto activated carbon fibers (ACFs) at high concentration and high adsorption temperatures. We tested three ACFs, four inlet concentrations of toluene (700, 1,200, 1,600, and 2,000 ppm), and four adsorption temperatures (25, 50, 75, and 200 °C). The composition and morphology of the ACFs were also analyzed using BET, FTIR, EA, and FESEM. The results indicated that the best toluene adsorption capacity was for 569 mg/g ACFs at a toluene concentration of 1,200 ppm and at 25 °C. A combination of low O content and high mesopore volume was desirable for ACFs with a high toluene adsorption capacity at high toluene concentrations. Moreover, the breakthrough time decreased with increasing toluene concentration, and the adsorption capacity of toluene increased significantly when the inlet concentration of toluene increased to 1,200 ppm. The data also indicated that the breakthrough time and the adsorption capacity of toluene decreased with increasing adsorption temperature. The outlet concentration of toluene did not reach 1,200 ppm when adsorption was saturated at 200 °C, as the oxygen functional groups on the ACF surface had reacted with toluene to form other compounds.
Chiou-Liang Lin; Yu-Hsiang Cheng; Zhen-Shu Liu; Jian-Yuan Chen. Adsorption and oxidation of high concentration toluene with activated carbon fibers. Journal of Porous Materials 2012, 20, 883 -889.
AMA StyleChiou-Liang Lin, Yu-Hsiang Cheng, Zhen-Shu Liu, Jian-Yuan Chen. Adsorption and oxidation of high concentration toluene with activated carbon fibers. Journal of Porous Materials. 2012; 20 (4):883-889.
Chicago/Turabian StyleChiou-Liang Lin; Yu-Hsiang Cheng; Zhen-Shu Liu; Jian-Yuan Chen. 2012. "Adsorption and oxidation of high concentration toluene with activated carbon fibers." Journal of Porous Materials 20, no. 4: 883-889.
This study focused on the effects of agglomeration/defluidization on the Cd, Pb and Cr distribution in bottom ash particles of different sizes. In this study we have incinerated artificial waste, which was a mixture of sawdust, polypropylene, selected metal solutions, and polyethylene. The experimental parameters included Na concentration, addition of Ca and Mg and operating temperature. The results indicated that particle size decreased by attrition and thermal impact in the absence of added Na. When Na was added to the system, this metal reacted with silica sand to form eutectics, which increased particle size. Further addition of Ca and Mg was found to prolong the operating time, with greater amounts of liquid eutectic accumulating, leading to increase particle size. The heavy metal concentrations in coarse and fine particles were greater than those present in particles of intermediate sizes over a range of experimental conditions. As the particle size decreased below 0.59 mm or increased above 0.84 mm, the heavy metal concentrations increased. As Ca and Mg were added, the heavy metal concentrations in particles of all sizes increased relative to those present in identical particles when no metals or only Na were added. Additionally, the ratio of Cd sorption to silica sand decreased with increasing Na concentration, but Cr sorption had the opposite tendency. Therefore, while the addition of Na tended to increase agglomeration, it also increased the tendency for heavy metals to remain in the sand bed of fluidized bed incinerators. Addition of Ca and Mg not only inhibited the agglomeration/defluidization process, resulting in increased operating time, but also enhanced the removal of heavy metals by silica sand, decreasing the concentration of heavy metals in reactor exhaust. Crown Copyright (C) 2010 Published by Elsevier B.V. All rights reserved
Zhen-Shu Liu; Chiou-Liang Lin; Jing-Dong Chou. Studies of Cd, Pb and Cr distribution characteristics in bottom ash following agglomeration/defluidization in a fluidized bed boiler incinerating artificial waste. Fuel Processing Technology 2010, 91, 591 -599.
AMA StyleZhen-Shu Liu, Chiou-Liang Lin, Jing-Dong Chou. Studies of Cd, Pb and Cr distribution characteristics in bottom ash following agglomeration/defluidization in a fluidized bed boiler incinerating artificial waste. Fuel Processing Technology. 2010; 91 (6):591-599.
Chicago/Turabian StyleZhen-Shu Liu; Chiou-Liang Lin; Jing-Dong Chou. 2010. "Studies of Cd, Pb and Cr distribution characteristics in bottom ash following agglomeration/defluidization in a fluidized bed boiler incinerating artificial waste." Fuel Processing Technology 91, no. 6: 591-599.