• Journal of the Korean GEO-environmental Society
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• v.13 no.7
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• pp.49-54
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• 2012

This study focuses on the decomposition of pentachlorophenol(PCP) by an electron beam (E-beam) process. To attain this objective, we investigated the reactive species generated from E-beam process during irradiation (reaction time 0.6 s) and G-values of PCP decomposition and effects of pH and $H_2O_2$ as an additive. The effect of pH values was independent on the decomposition of PCP. However, during E-beam irradiation a scavenging effect of added $H_2O_2$ (> 1mM) for the decomposition of PCP was shown, which was supported by the decreased amounts of $Cl^-$ produced by the decomposition of PCP. Meanwhile, oxalic acid and unidentified organic chlorine compounds as by-products were increased by the addition of $H_2O_2$. Thus, in order to enhance the efficiency of PCP decomposition, the E-beam process has to consider a proper concentration of $H_2O_2$ as a well-known source of strong oxidant hydroxyl radical.

• Journal of the Korean GEO-environmental Society
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• v.13 no.10
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• pp.69-76
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• 2012

This study focuses both on the quantitative measurement of hydroxyl radicals formed by an electron beam (E-beam) process and on the decomposition of pentachlorophenol(PCP) in the presence of $H_2O_2$ and $Fe^{3+}-EDTA$ as additives. To attain this objective, the quantitative measurement of hydroxyl radical was performed with the hydroylation of benzoic acid (BA), producing hydroxybenzoic acid (OHBA). As a result, the concentrations of hydroxyl radical measured were lower than those of hydroxyl radical predicted. Probably, it indicates that the reactive species generated during E-beam irradiation are able to scavenge the hydroxyl radicals. In particular, the degradation of PCP was promoted by the addition of $H_2O_2$ (< 1mM). On the other hand, its degradation as well as the generation of chloride ions as a by-product was inhibited by the addition of $H_2O_2$ (> 1mM), and thus carbon yield(%) of oxalic acid as a by-product was increased. During E-beam irradiation the addition of $Fe^{3+}-EDTA$ effectively decomposed the PCP, thus increasing the G-values. Considering the formation of OHBA and the decomposition of PCP, these results suggest that the addition of $Fe^{3+}-EDTA$ in the E-beam process can produce the further hydroxyl radicals and enhance the efficiency of PCP decomposition at low dose.

• Applied Biological Chemistry
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• v.35 no.4
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• pp.242-247
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• 1992

Twenty strains of pentachlorophnol (PCP) resistant bacteria were isolated from activated sludge of the sewage treatment plant of Jung Lang Chun, Seoul. The predominant strains were Bacillus spp. including B. sphaericus and E. schlegelii. The other strains were identified as Corynebacterium spp., Staphylococcus aureus, Arthrobacter spp. and Aeromonas spp. The resistant strains could be grouped into two categories; PCP-degrading and PCP-adsorbing/absorbing ones. PCP-degrading strains degraded $75{\sim}90%$ of PCP in the medium containing 100 ppm PCP during the first 24 hours of growth. At the initial period the PCP-adsorbing/absorbing strains removed PCP from the medium but started to release PCP after 24 or 72 hours of growth. PCP degradation products from the culture broth of PCP-degrading strains were identified by comparing their $R_f$ values with those of the reference compounds. 2-chlorophenol and 2.4-dichlorophenol were presumed to be the intermediate products of PCP degradation.

• The Korean Journal of Applied Statistics
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• v.21 no.6
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• pp.911-921
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• 2008

Visualization of the gene expression data on a low-dimensional graph is helpful in uncovering biological information contained in the data. In this study, we focus on two modified versions of the parallel coordinate plot. First one is the ePCP(enhanced parallel coordinate plot) which shows "near smooth" connecting curves between axes spaced proportionately to the proximity of re-ordered variables. Second one is APCP(Andrews' type parallel coordinate plot) which is obtained by rotating Andrews' plot that has a form of the parallel coordinate plot. Visualization procdures using ePCP and APCP are given for the lymphoma data case.

• Journal of Korean Society on Water Environment
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• v.20 no.6
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• pp.577-582
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• 2004

The photocatalytic degradation of atrazine and PCP, a endocrine disruptors, has been investigated over $TiO_2$ photocatalysts under ultraviolet (UV) light irradiation. The effect of operational parameters, i.e., pH, light intensity and persulphate concentration on the degradation rate of aqueous solution of atrazine and PCP has been examined. The results presented in this work demonstrate that, as pH and the light intensity increased, the photocatalytic reaction rates were enhanced. Individual use of $TiO_2$-persulphate was far more effective than using only $TiO_2$ in atrazine and PCP removal. Based on the overall experimental results, the photocatalytic oxidation of atrazine and PCP with the coated $TiO_2$ photocatalyst is found to be very effective under the operational conditions delineated in this study.

• Journal of Microbiology and Biotechnology
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• v.28 no.11
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• pp.1908-1915
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• 2018

Upon viral infection, the host cell recognizes the invasion through a number of pattern recognition receptors. Melanoma differentiation associated gene 5 (MDA5) and retinoic acid-inducible gene-I (RIG-I) recognize RNA molecules derived from invading viruses, activating down-stream signaling cascades, culminating in the induction of the type I interferon. On the other hand, viruses have evolved to evade type I interferon-mediated inhibition. Hepatitis E virus has been shown to encode a few antagonists of type I interferon and it is not surprising that viruses encode multiple mechanisms of viral evasion. In the present study, we demonstrated that HEV PCP strongly down-regulates MDA5-mediated activation of interferon ${\beta}$ induction in a dose-dependent manner. Interestingly, MDA5 protein expression was almost completely abolished. In addition, polyinosinic polycytidylic acid (poly(I:C))- and Sendai virus-mediated activation of type I interferon responses were similarly abrogated in the presence of HEV PCP. Furthermore, HEV PCP down-regulates several molecules that play critical roles in the induction of type I IFN expression. Taken together, these data collectively suggest that HEV-encoded PCP is a strong antagonist of type I interferon.

• Biotechnology and Bioprocess Engineering:BBE
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• v.11 no.5
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• pp.462-465
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• 2006

An important issue in the oxidation of pentachlorophenol (PCP) by the enzyme horseradish peroxidase (HRP) is enzyme inactivation during the reaction. This study was initiated to investigate the ability of two nonionic surfactants (Tween 20 and Tween 80) to mitigate HRP inactivation. The surfactants were tested at concentrations below and above their critical micelle concentrations (CMCs). Enhancement of PCP oxidation was observed at sub-CMCs, indicating effective protection of HRP by the two surfactants. Maximum levels of PCP removal were observed when the concentrations of Tween 20 and Tween 80 were 40 and 50% of the CMCs, respectively At supra-CMCs, both surfactants caused a noticeable reduction in the extent of PCP removal.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.8
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• pp.1104-1113
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• 2014

The effects of feeding pelleted citrus pulp (PCP) as a natural antioxidant source on the performance and milk quality of dairy cows fed highly polyunsaturated fatty acid (FA) diets were evaluated. Four lactating Holstein cows were assigned to a $4{\times}4$ Latinsquare. Treatments, on a dry matter (DM) basis, were i) control diet; ii) 3% soybean oil; iii) 3% soybean oil and 9% PCP and; iv) 3% soybean oil and 18% PCP. When cows fed on citrus pulp, the DM intake tended to decrease. The total tract apparent digestibility of DM and ether extract decreased when cows fed on the control diet compared to other diets. Cows fed PCP had higher polyphenols and flavonoids content and higher total ferric reducing antioxidant power (FRAP) in milk compared to those fed no pelleted citrus pulp. Cows fed 18% PCP showed higher monounsaturated FA and lower saturated FA in milk fat compared with cows fed the other diets. The lowest n-6 FA proportion was in milk fat from cows fed control. The present study suggests that pelleted citrus pulp added to 9% to 18% DM increases total polyphenols and flavonoids concentration, and the FRAP in milk.

• Atmosphere
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• v.18 no.4
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• pp.507-524
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• 2008

In this paper, future climate changes over East Asia($20^{\circ}{\sim}50^{\circ}N$, $100^{\circ}{\sim}150^{\circ}E$) are projected by anthropogenic forcing of greenhouse gases and aerosols using coupled atmosphere-ocean general circulation model (AOGCM) simulations based on Intergovernmental Panel on Climate Change (IPCC) Special Report on Emissions Scenarios (SRES) B1, A1B and A2 scenarios. Before projection future climate, model performance is assessed by the $20^{th}$ Century (20C3M) experiment with bias, root Mean Square Error (RMSE), ratio of standard deviation, Taylor diagram analysis. The result of examination of the seasonal uncertainty of T2m and PCP shows that cold bias, lowered than that of observation, of T2m and wet bias, larger than that of observation, of PCP are found over East Asia. The largest wet bias is found in winter and the largest cold bias is found in summer. The RMSE of temperature in the annual mean increases and this trend happens in winter, too. That is, higher resolution model shows generally better performances in simulation T2m and PCP. Based on IPCC SRES scenarios, East Asia will experience warmer and wetter climate in the coming $21^{st}$ century. It is predict the T2m increase in East Asia is larger than global mean temperature. As the latitude goes high, the warming over the continents of East Asia showed much more increase than that over the ocean. An enhanced land-sea contrast is proposed as a possible mechanism of the intensified Asian summer monsoon. But, the inter-model variability in PCP changes is large.

• Proceedings of the Korean Environmental Health Society Conference
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• 2004.06a
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• pp.146-150
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• 2004

Degradation efficiency of pentachlorophenol (PCP) by using direct UV photolysis and $TiO_2$ photocatalysis was evaluated with both chemical analyses and acute toxicity assessment employing luminescent bacteria Vibrio fischeri. PCP was chosen as a target compound in this study because of its wide application as fungicide, bactericide, insecticide and wood preservative in agriculture and many industries, in addition to its well-known environmental consequences. The acute toxicity to the microbe was reduced by >60% when applying UV alone, and was completely removed when treated with $UV-TiO_2$ combinations. Toxicity reduction pattern determined with the Microtox Assay generally corresponds with the chemistry data: However, it should be noted that toxicity was greater than expected by the chemistry data. Formation of TCBQ, a toxic byprodut, could not explain observed microbial toxicity. These observations are probably due to the presence of unidentified toxic PCP byproducts, which may include polychlorinated dibenzodioxins and polychlorinated dibenzofurans. When Microtox results were compared between different exposure time, i.e.,5 min and 15 min, an interesting pattern was noted with $UVA-\;TiO_2$ treatment. While no microbial toxicity was observed with 5 min exposure, an EC50 value of 45.4% was estimated with 15 min exposure, which was not observed in $UVB-\;TiO_2$ exposure. This result may suggest the presence of unidentified toxic degradation products generated in the later stage of treatment. Based on this study, $TiO_2$ photocatalyst, together with UVB photolysis could improve the removal of both PCP and its toxic derivatives in more efficient way. The Microtox Assay is promising and economical method for monitoring efficiency of wastewater treatment processes.