• Journal of Korean Society on Water Environment
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• v.26 no.1
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• pp.35-43
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• 2010

This experimental design and response surface methodology (RSM) have been applied to the investigation of the electrocoagulation/flotation of dye wastewater. The electrocoagulation/flotation reactions were mathematically described as a function of parameters current (A), NaCl concentration (B), initial RhB concentration (C) and time (D) being modeled by use of the central composite design (CCD). The application of RSM using the CCD yielded the following regression equation, which is an empirical relationship between the RhB removal (%) and test variables in RhB removal (%) = $-300.42+129.21{\cdot}Current+46.99{\cdot}NaCl-0.11{\cdot}RhB-+43.71{\cdot}Time-5.67{\cdot}Current{\cdot}NaCl-3.18{\cdot}Current{\cdot}Time-2.41{\cdot}NaCl{\cdot}Time-19.79{\cdot}Current^2-2.27{\cdot}NaCl^2-1.59{\cdot}Time^2$. the model predictions agreed well with the experimentally observed result ($R^{2}=0.9728$). The estimated ridge of maximum response and optimal conditions for RhB removal (%) using canonical analysis was 99.4% (A: 1,77 A, NaCl concentration: 2.23 g/L, RhB concentration: 56.12 mg/L, Time: 9.98 min). To confirm this optimum condition, three additional experiments were performed and RhB removal (%) were within range of 86.87% (95% PI low)~111.93% (95% PI high) obtained.

• Fisheries and Aquatic Sciences
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• v.1 no.1
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• pp.42-47
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• 1998

The chemiluminescent (CL) response of phagocytes from juvenile rockfish, Sebastes schlegeli, which were administered orally with levamisole was investigated. The fish intubated with doses of levamisole either at 0.5mg $kg^-$ or 1 mg $kg^-$body weight showed significant increase in CL responses at two weeks after the administration. The increased extent of CL in the fish exposed to 0.5 mg $kg^-$ body weight was considerably lower than that in the fish exposed to 1 mg $kg^-$. The fish exposed to 5 mg $kg^-$ body weight showed a steady and significant increase of CL response after the intubation. The fish intubated with 10 mg of levamisole $kg^-$ body weight, however, showed no significant differences in CL response after the administration. In the experiment of feeding experimental diet, a lower dose of levamisole induced immunostimulation of phagocytes, but higher doses of levamisole induced immunosuppression of phagocytes. At one week after marking and blood sampling, plasma glucose level was significantly increased in the control group and the group intubated 0.5 mg levamisole/kg body weight. However, the fish in another groups, which were administered higher levels of levamisole, showed no significant difference in glucose level after marking and blood sampling. The result of the present study suggests that levamisole can be used as a potent immunostimulator in rockfish by oral administration, and the immunomodulating activity of levamisole depends on the dosage used.

• Food Science of Animal Resources
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• v.35 no.6
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• pp.815-823
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• 2015

This study developed probabilistic models to describe Listeria monocytogenes growth responses in meat products with low concentrations of NaNO₂ and NaCl. A five-strain mixture of L. monocytogenes was inoculated in NBYE (nutrient broth plus 0.6% yeast extract) supplemented with NaNO₂ (0-141 ppm) and NaCl (0-1.75%). The inoculated samples were then stored under aerobic and anaerobic conditions at 4, 7, 10, 12, and 15℃ for up to 60 d. Growth response data [growth (1) or no growth (0)] for each combination were determined by turbidity. The growth response data were analyzed using logistic regression to predict the growth probability of L. monocytogenes as a function of NaNO₂ and NaCl. The model performance was validated with the observed growth responses. The effect of an obvious NaNO₂ and NaCl combination was not observed under aerobic storage condition, but the antimicrobial effect of NaNO₂ on the inhibition of L. monocytogenes growth generally increased as NaCl concentration increased under anaerobic condition, especially at 7-10℃. A single application of NaNO₂ or NaCl significantly (p<0.05) inhibited L. monocytogenes growth at 4-15℃, but the combination of NaNO₂ or NaCl more effectively (p<0.05) inhibited L. monocytogenes growth than single application of either compound under anaerobic condition. Validation results showed 92% agreement between predicted and observed growth response data. These results indicate that the developed model is useful in predicting L. monocytogenes growth response at low concentrations of NaNO₂ and NaCl, and the antilisterial effect of NaNO₂ increased by NaCl under anaerobic condition.

• Microbiology and Biotechnology Letters
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• v.48 no.1
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• pp.48-56
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• 2020

This study aimed to optimize the culture conditions to improve the crude biosurfactant activity of Bacillus pumilus IJ-1, using a 3³ full-factorial design of response surface methodology (RSM). It was found that submerged fermentation of B. pumilus improved the activity of the crude biosurfactant. The factors selected for optimization were NaCl concentration, temperature, and tryptone concentration. Response surface analysis revealed that the fitted quadratic model was statistically significant and produced an adequate R² value (0.9898) and a low probability value (<0.0001). The optimum level for each factor was found to be 0.567% (w/v) NaCl, 21.851℃ and 0.765% (w/v) tryptone, respectively. Crude biosurfactant activity was found to be most affected by tryptone concentration; then temperature, and finally NaCl concentration. Our results may potentially facilitate large-scale biosurfactant production from B. pumilus IJ-1.

• Journal of fish pathology
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• v.17 no.3
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• pp.217-222
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• 2004

This study was performed to investigate the immunological side effects of chloramphenicol (CAP) on olive flounder, Paralichthys olivaceus. To investigate immunological effects on olive flounder, we determined the changes of chemiluminescence (CL) response of flounder kidney-derived leucocyte after the treatment of CAP in vivo and in vitro. The CL activity was significantly decreased in a dose-dependent manner during the treatment of CAP in vitro. Similarly, a dose-dependent reduction of CL response, although not significant, were observed during the treatment of CAP in vivo. The results suggest that CAP reduced the function of flounder phagocytosis in vivo and in vitro, indicating the immunosuppressive ability of CAP.

• Korean Journal of Medicinal Crop Science
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• v.28 no.1
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• pp.1-8
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• 2020

Background: This study was conducted to investigate the effects of NaCl concentration on the photosynthetic parameters, chlorophyll fluorescence and growth characteristics of Crepidiastrum sonchifolium. Methods and Results: As treatments, we subjected C. sonchifolium plants to four different concentrations of NaCl (0, 50, 100 and 200 mM). We found that the photosynthetic parameters maximum photosynthesis rate (P_{N max}), net apparent quantum yield (Φ), maximum carboxylation rate (V_cmax), and maximum electron transport rate (J_max) were significantly reduced at an NaCl concentration greater than 100 mM. In contrast, there was an increase in water-use efficiency with increasing NaCl concentration, although in terms of growth performances, leaf dry weight, root dry weight, stem length, and total dry weight all decreased with increasing NaCl concentration. Furthermore, leakage of electrolytes, as a consequence of cell membrane damage, clearly increased in response to an increase in NaCl concentration. Analysis of the polyphasic elevation of chlorophyll a fluorescence transients (OKJIP) revealed marked decrease in flux ratios (Φ_PO, Ψ_O and Φ_EO) and the PI_abs, performance index in response to treatment with 200 mM NaCl, thereby reflectings the relatively reduced state of photosystem II. This increase in fluorescence could be due to a reduction in electron transport beyond Q^-_A. We thus found that the photosynthetic parameters, chlorophyll fluorescence and growth characteristics of C. sonchifolium significantly increased in response to treatment with 200 mM NaCl. Conclusions: Collectively, the findings of this study indicate that C. sonchifolium shows relatively low sensitivity to NaCl stress, although photosynthetic activity was markedly reduced in plants exposed to 200 mM NaCl.

• Proceedings of the KIEE Conference
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• 1990.11a
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• pp.139-142
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• 1990

A gas sensor, comprised of both ZnO and $PdCl_2$ powders, has been developed to sense the CO gas of low concentration (100 ppm). When the weight ratio of ZnO/$PdCl_2$ element sintered at $600^{\circ}C$ was 99.5/0.5, the maximum sensitivity to CO gas was obtained at the operating temperature of $200^{\circ}C$. Also, the response characteristics of this element were examined, and then the response time was decreased from 90 to 45 sees, with operating temperature increase in the range of $100-400^{\circ}C$.

• Journal of Environmental Science International
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• v.19 no.7
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• pp.889-900
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• 2010

The experimental design and response surface methodology (RSM) have been applied to the investigation of the electro-UV complex process for the disinfection of E. coli in the water. The disinfection reactions of electro-UV process were mathematically described as a function of parameters power ($X_1$), NaCl dosage ($X_2$), initial pH ($X_3$) and disinfection time ($X_4$) being modeled by use of the Box-Behnken technique. The application of RSM using the Box-Behnken technique yielded the following regression equation, which is an empirical relationship between the residual E. coli number and test variables in actual variables: Ln (CFU) = 23.57 - 0.87 power - 1.87 NaCl dosage - 2.13 pH - 2.84 time - 0.09 power time - 0.07 NaCl dosage pH + 0.14 pH time + 0.03 $power^2$ + 0.47 NaCl $dosage^2$ + 0.20 $pH^2$+ 0.33 $time^2$. The model predictions agreed well with the experimentally observed result ($R^2$ = 0.9987). Graphical response surface and contour plots were used to locate the optimum point. The estimated ridge of maximum response and optimal conditions for the E. coli disinfection using canonical analysis was Ln 1.06 CFU (power, 15.40 W; NaCl dosage, 1.95 g/L, pH, 5.94 and time, 4.67 min). To confirm this optimum condition, the obtained number of the residual E. coli after three additional experiments were Ln 1.05, 1.10 and Ln 1.12. These values were within range of 0.62 (95% PI low)~1.50 (95% PI high), which indicated that conforming the reproducibility of the model.

• Food Science of Animal Resources
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• v.30 no.3
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• pp.359-364
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• 2010

Lactobacillus acidophilus A12 was isolated from chicken feces for use as an immunostimulating livestock probiotic. The purpose of this study was to optimize the production of L. acidophilus A12 using response surface methodology (RSM). Initially, the influence of growth medium was studied in terms of carbon sources (glucose, fructose, lactose, glycerol, sucrose, ethanol, and mannitol), nitrogen sources (beef extract, yeast extract, malt extract, and tryptone), and inorganic salts ($CaCl_2$, $MgSO_4$, $KH_2PO_4$, $(NH_4)_2SO_4$, $FeSO_4$, and NaCl). Through one factor-at-a time experiment, lactose, yeast extract, and $CaCl_2$ were determined to be the best sources of carbon, nitrogen, and inorganic salt, respectively. The optimum composition was found to be 17.7 g/L lactose, 18.6 g/L yeast extract, and 0.9 g/L $CaCl_2$. Under these conditions, a maximum cell density of 9.33 Log CFU/mL was produced, similar to the predicted value.

• Applied Biological Chemistry
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• v.40 no.6
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• pp.567-571
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• 1997

Numbers of chemical agents which have been shown to inhibit either auxin signal transduction pathway or ethylene formation in plant cells were applied to cut flower stems of snapdragon (Antirrhinum majus L.) and their effects on the postharvest gravitropic response were studied. The chemical treatments were done by submerging either the stem base or the top part of cut flower, which involves the gravistimulus-sensitive region, for 1 h at $25^{\circ}C$. When the chemicals were supplied from the cut stem base, the gravitropic upward bending of flower stalks kept horizontally after the treatments with 20 mM CDTA or 10 mM $CoCl_2$ was comparable to that of the untreated control, but o-vanadate showed a certain degree of effectiveness for suppressing the bending response. In contrast, the direct application of those agents to the gravitropically sensitive region of cut flowers in the presence of 0.01% Triton X-100 resulted in a substantial reduction of the gravitropic response. In the case of 20 mM $CoCl_2$ treatment, almost total elimination of gravitropism without any significant deterioration of flower quality was observed. The results indicate the possibility of preparation of a protocol involving $CoCl_2$ and a proper surfactant for commercial use to suppress the gravitropic response of cut flowers during postharvest storage and transportation.