• Journal of Bio-Environment Control
• /
• v.20 no.4
• /
• pp.406-411
• /
• 2011

This study was conducted to find out the effect of cut-off period (0 hour, 3 hours, 6 hours, 12 hours, and 24 hours) to supply nutrient solution for chicon forcing at that was predrying treatment on the storability of chicon. The cut-off treatment increased dry matter rate, respiration rate, and ethylene production rate. The dry matter rate of chicon increased, as the cut-off period increased, but the respiration rate and ethylene production rate of chicon was highest in 12 hours and 6 hours cut-off treatment, respectively, and then their rates decreased, as the cut-off period prolonged. The weight loss at cut-off 6 hours treatment was lower than other treatments during $10^{\circ}C$ storage temperature. The cut-off 6 hours treatment showed higher carbon dioxide and oxygen concentration in 10,000 cc/$m^2$/day/atm oxygen permeability film package during storage period than control and showed a little predrying effect but was not statistically significant. At $4^{th}$ day, the ethylene concentration reached higher than other storage day and after that decreased but was not statistically significant. The quality of chicon for 3 hours, 6 hours, 24 hours cut-off treatments on storability showed higher than other treatments, accordingly. The 6 hours cut-off treatment showed the inhibited effect of the degree of browning of chicon cutting plane. The effect of 6 hours cut-off treatment on storability of chicon showed proper predrying effect, reduced moisture loss and browning inhibition apparently during $10^{\circ}C$ storage.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.39 no.5
• /
• pp.776-781
• /
• 2010

The properties and bactericidal activities of strongly acidic electrolyzed water (SEW) against food-borne pathogenic bacteria, vegetables and kitchen apparatuses were investigated. The available chlorine concentration, pH and oxidation reduction potential (ORP) of SEW were $35{\pm}1.2\;ppm$, $2.3{\pm}0.2$, and $1,140{\pm}20.4\;mV$, respectively. Five strains of food-borne bacteria with initial cell number of 7.00 log CFU/mL were not detected except Bacillus cereus after treatment with SEW for 60 sec. The numbers of Bacillus cereus were reduced to 2.08{\pm}1.00 log CFU/mL at the same condition. In vegetables, SEW treatment after washing strongly in alkalic electrolyzed water (AEW) showed better bactericidal effects than SEW only. The viable cell on stainless steel bowl ($3.86{\pm}2.49\;\log\;CFU/100\;cm^2$) and cup for water ($2.40{\pm}1.80\;\log\;CFU/100\;cm^2$) were not detected by SEW treatment (35 ppm of available chlorine concentration) for 30 sec, but survival of more than 1.00 log CFU/$100\;cm^2$ of viable cell was shown by washing of sodium hypochlorite solution at the same condition. On the other hand, the coliform group bacteria ($5.08{\pm}4.00\;CFU/100\;cm^2$) were detected on rubber globe only, and more than 2.00 log CFU/$100\;cm^2$ of viable cell and coliform group bacteria on it survived, though it was washed with flowing SEW for 30 sec.

• Microbiology and Biotechnology Letters
• /
• v.37 no.2
• /
• pp.118-124
• /
• 2009

Esterase EM2L8 gene isolated from deep sea sediment was expressed in Escherichia coli BL21 (DE3) and the esterase activity of the cell-free extract was assayed using p-nitrophenyl butyrate-spectrophotometric method. Its optimum temperature was $40-45^{\circ}C$ and 45% activity of the maximum activity was retained at $15^{\circ}C$. The activation energy at $15-45^{\circ}C$ was calculated to be 4.9 kcal/mol showing that esterase EM2L8 was a typical cold-adapted enzyme. Enzyme activity was maintained for 6 h and 4 weeks at $30^{\circ}C$ and $4^{\circ}C$, respectively. When each ethanol, methanol, and acetone was added to the reaction mixture to 15% concentration, enzyme activity was maintained. In the case of DMSO, enzyme activity was kept up to 40% concentration. (S)-4-Chloro-3-hydroxy butyric acid is a chiral intermediate for the synthesis of Atorvastatin, a hyperlipemia drug. When esterase EM2L8 (40 U) was added to buffer solution (1.2 mL, pH 9.0) containing ethyl-(R,S)-4-chloro-3-hydroxybutyrate (38 mM), it was hydrolyzed into 4-chloro-3-hydroxy butyric acid with a rate of $6.8\;{\mu}mole/h$. The enzyme hydrolyzed (S)-substrate more rapidly than (R)-substrate. When conversion yield was 80%, e.e.s value was 40%. When DMSO was added, hydrolysis rate increased to $10.4\;{\mu}mole/h$. The plots of conversion yield vs e.e.s in the presence or absence of DMSO were almost same, implying that the reaction enantioselectivity was not changed by the addition of DMSO. Taken together, esterase EM2L8 had high activity and stability at low temperatures as well as in various organic solvents/aqueous solutions. These properties suggested that it could be used as a biocatalyst in the synthesis of useful pharmaceuticals.

• Korean Journal of Environmental Agriculture
• /
• v.12 no.1
• /
• pp.51-57
• /
• 1993

Objective of this research was to assess the influence of reaction time on the heavy metal-organic ligand complexation by employing kinetic models. Aqueous solutions of humic (HA) or fulvic acid (FA) were reacted with metal solutions with 1:1 ratio to form complexes. Efficiency of organic ligand on metal removal was determined by separating the precipitates from solution using $0.45\;{\mu}m$ filter paper. Complexation between Cu or Pb and HA or FA followed the first- or multiple first order kinetics, largely depending on metal concentration and kind of organic ligand. Amounts of precipitates were increased proportionally with reaction time but reached to quasiequilibrium where rate of precipitate formation was not varied with time. Copper-ligand complexation was, irrespective of ligand, fitted to the single first order kinetics at Cu concentrations lower than $300{\mu}M$, but this was fitted to the multiple first order kinetics at Cu concentrations higher than $300{\mu}M$. As increasing Cu concentrations, the precipitates formed more readily, judging from the increased rate constants (${\kappa}$). In the multiple first order kinetics, ${\kappa}$ was decreased as reaction steps proceeded. Most of Cu-ligand precipitates were formed within 15 min. FA precipitated Cu more rapidly than HA did. ${\kappa}$ for Pb-HA complexation was decreased but that for Pb-FA reaction was increased, as increasing Pb concentration. Most of Pb-organic ligand complexation occurred within 30 min. Afterwards, ${\kappa}$ values were relatively small and not affected much by time. Pb was precipitated by humic acid more readily than Cu when metal concnetrations were $200{\sim}300{\mu}M$. However, when metal concentrations were in the ranges of $400{\sim}500{\mu}M$, a reversed tendency was observed.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.6
• /
• pp.527-535
• /
• 2020

The purpose of this study was to establish a simple vitrification protocols to preserve animal cell lines derived from tissues of livestock that could be recultured. Bovine oviduct epithelial cells (BOEC) were used for the vitrification process using a 0.25 ml straw to increase cryopreservation efficiency. BOEC was cultured from the oviduct of 3.5-day estrus state, and the commercially available polyampholyte StemCell Keep^TM was used as a cryoprotective agent. Using different concentrations, the viability rates of BOEC in 5, 10, 25, 50, 75, and 100% in freezing media were investigated. Survivability was determined using a differential staining technique using a trypan blue test and a CYTO-13/PI staining protocol. The viability rates of BOEC in the trypan blue test were 5.6±11.8, 12.5±7.2, 53.0±2.7, 85.1±6.9, 79.8±0.6, and 60.7±6.7% with a respective concentration of StemCell Keep^TM. The viability rates in CYTO-13/PI staining were 4.6±2.5, 30.8±12.1, 58.4±2.5, 85.5±1.2, 79.8±0.6, and 71.2±1.2%, respectively. These results indicate that BOEC could be preserved with StemCell Keep^TM without toxicity in a 0.25-ml straw. The optimal concentration of vitrification solution with StemCell Keep^TM was determined to be 50% and can be considered as a proper preservation method for cryobanking.

• The Korean Journal of Rheology
• /
• v.10 no.4
• /
• pp.234-246
• /
• 1998

The objective of this study is to investigate the correlation between steady shear flow (nonlinear behavior) and dynamic viscoelastic (linear behavior) properties for concentrated polymer solutions. Using both an Advanced Rheometic Expansion System(ARES) and a Rheometics Fluids Spectrometer (RFS II), the steady shear flow viscosity and the dynamic viscoelastic properties of concentrated poly(ethylene oxide)(PEO), polyisobutylene(PIB), and polyacrylamide(PAAm) solutions have been measured over a wide range of shear rates and angular frequencies. The validity of some previously proposed relationships was compared with experimentally measured data. In addition, the effect of solution concentration on the applicability of the Cox-Merz rule was examined by comparing the steady flow viscosity and the magnitude of the complex viscosity Finally, the applicability of the Cox-Merz rule was theoretically discussed by introducing a nonlinear strain measure. Main results obtained from this study can be summarized as follows : (1) Among the previously proposed relationships dealt with in this study, the Cox-Merz rule implying the equivalence between the steady flow viscosity and the magnitude of the complex viscosity has the best validity. (2) For polymer solutions with relatively lower concentration, the steady flow viscosity is higher than the complex viscosity. However, such a relation between the two viscosities is reversed for highly concentrated polymer solutions. (3) A nonlinear strain measure is decreased with increasing stran magnitude, after reaching the maximum value in small strain range. This behavior is different from the theoretical prediction demonstrating the shape of a damped oscillatory function. (4) The applicability of the Cox-Merz rule is influenced by the $\beta$ value, which indicates the slope of a nonlinear stain measure (namely, the degree of nonlinearity) at large shear deformations. The Cox-Merz rule shows better applicability as the $\beta$ value becomes smaller.

• Journal of Yeungnam Medical Science
• /
• v.8 no.2
• /
• pp.128-137
• /
• 1991

Peritoneal dialysis has been widely considered to be the dialytic treatment of choice for acute renal failure in infants and young children, because the technique is simple, safe and easily adapted for these patients. Also peritoneal dialysis in infants might have more effective ultrafiltration and clearance than in adults. In certain circumstances associated with hemodynamic instability, ordinary volume peritoneal dialysis(30-50 ml/kg body weight per exchange) or hemodialysis may not be suitable unfortunately. But frequent cycled, low volume, high concentration peritoneal dialysis may be more available to manage the hemodynamically untable acute renal failure of newborns and infants. Seven infants underwent peritoneal dialysis for hemodynamically unstable acute renal failure with low exchange volume($14.2{\pm}4.2ml/kg$), short exchange time(30 to 45 minutes) and hypertonic glucose solution(4.25% dextrose). Age was $1.9{\pm}1.3$ months and body weight was $4.6{\pm}1.6kg $. Etiology of acute renal failure was secondary to sepsis with or without shock(5 cases) and postcardiac operation(2 cases). Catheter was inserted percutaneously with pigtail catheter or Tenkhoff catheter by Seldinger method. Dialysate was commercially obtained Peritosol which contained sodium, chloride, potassium, magnesium, lactate and calcium. Net ultrafiltration(ml/min) showed no difference between low volume dialysis and control($0.27{\pm}0.09$ versus $0.29{\pm}0.09$) Blood BUN decreased from $95.7{\pm}37.5$ to $75.7{\pm}25.9mg/dl$ and blood pH increased from $7.122{\pm}0.048$ to $7.326{\pm}0.063$ after 24 hours of peritoneal dialysis. We experienced hyperglycemia which were controlled by insulin(2 episodes), leakage at the exit site(2), mild hyponatremia(1) and Escherichia coli peritonitis(1). Two children of low volume dialysis died despite the treatment. In our experience, low volume and high concentration peritoneal dialysis with frequent exchange may have sufficient ultrafiltration and clearance without significant complications in the certain risked acute renal failure of infants.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.38 no.3
• /
• pp.267-273
• /
• 2009

Antioxidative, antimicrobial activities and Raw 264.7 cell viability as cytotoxicity of various solvent extracts from leaf of Eriobotrya japonica Lindl. dried by different methods were investigated for processing as functional ingredient. In DPPH radical scavenging activity, RLE (80% EtOH extract of raw leaf) and FLE (80% EtOH extract of freeze-dried leaf) exhibited strong scavenging effect on $300{\mu}M$ DPPH radical solution (1.71 mg/mL and 2.11 mg/mL for RLE $SC_{50}$ and FLE $SC_{50}$). Also in nitric oxide scavenging activity, RLE and FLE showed strong activities (83.9% and 82.2% in 5 mg/mL sample concentration). Total phenolic compound contents of each extracts were found to be $73.7{\sim}215.4$ mg/g and RLE was showed the highest phenolic compound content. Also, total flavonoid contents were found to be $24.85{\sim}110.3$ mg/g and RLE was showed the highest flavonoid content. In antimicrobial activity, RLE was showed higher growth inhibition effect against all microbial strains. RLE, RLW (hot water extract of raw leaf), and FLW (hot water extract of freeze-dried leaf) exhibited strong antimicrobial activities against MRSA and S. aureus. In measurement of cytotoxicity by MTT assay, Raw 264.7 cell viabilities of 80% EtOH extracts showed better effect than water extracts. Especially viability of RLE was found be over 100% in every tested sample concentration.

• Applied Chemistry for Engineering
• /
• v.34 no.3
• /
• pp.258-263
• /
• 2023

In this study, conductive polymers and the enzyme tyrosinase (Tyr) were deposited on the surface of a screen printed carbon electrode (SPCE), which can be fabricated as a disposable sensor chip, and applied to the detection of bisphenol F (BPF), an endocrine disruptor with proven links to male diseases and thyroid disorders, using electrochemical methods. On the surface of the SPCE working electrode, which was negatively charged by oxygen plasma treatment, a positively charged conductive polymer, poly(diallyldimethyl ammonium chloride) (PDDA), a negatively charged polymer compound, poly(sodium 4-styrenesulfonate) (PSS), and another layer of PDDA were layered by electrostatic attraction in the order of PDDA, PSS, and finally PDDA. Then, a layer of Tyr, which was negatively charged due to pH adjustment to 7.0, was added to create a PDDA-PSS-PDDA-Tyr sensor for BPF. When the electrode sensor is exposed to a BPF solution, which is the substrate and target analyte, 4,4'-methylenebis(cyclohexa-3,5-diene-1,2-dione) is generated by an oxidation reaction with the Tyr enzyme on the electrode surface. The reduction process of the product at 0.1 V (vs. Ag/AgCl) generating 4,4'-methylenebis(benzene-1,2-diol) was measured using cyclic and differential pulse voltammetries, resulting in a change in the peak current with respect to the concentration of BPF. In addition, we compared the detection performance of BPF using an ionic liquid electrolyte as an alternative to phosphate-buffered saline, which has been used in many previous sensing studies. Furthermore, the selectivity of bisphenol S, which acts as an interfering substance with a similar structure to BPF, was investigated. Finally, we demonstrated the practical applicability of the sensor by applying it to analyze the concentration of BPF in real samples prepared in the laboratory.

• Economic and Environmental Geology
• /
• v.36 no.5
• /
• pp.375-380
• /
• 2003

This study was carried out 1) to investigate the pH effect on solubilization of phenanthrene by biosurfactant in aqueous system and 2) to evaluate the pH effect on the biodegradation rate of phenanthrene in the presence and the absence of the biosurfactant by phenanthrene degraders. Tween 80, which is a chemically synthesized surfactant, showed greater solubilizing capacity than rhamnolipid. The solubilization capacity can be expressed as a MSR(molar solubilization ratio=moles of organic compounds solubilized per mole of surfactant). The calculated MSR of Tween 80 and rhamnolipid were 0.1449 and 0.0425 respectively. The kinetic study of phenanthrene solubilization by rhamnolipid showed that solubilization mechanism could reach equilibrium within 24 hours. Addition of 240 ppm rhamnolipid solution, which concentration is 4.3 times of Critical Micelle Concentration(CMC), caused 9 times solubility enhancement compared to water solubility. The highest solubilities were detected around a pH range of 4.5-5.5. Changes in apparent solubility with the changes in pH are possibly related to the fact that the rhamnolipid, an anionic surfactant, can form different structures depending on the pH. Two biodegradation experiments were performed in the absence and the presence of rhamnolipid, with the cell growth investigated using a spread plate method. The specific growth rates at pH 6 and 7 were higher than at the other pH, and the HPLC analysis data, for the total phenanthrene loss, confirmed the trends in the $\mu$(specific growth rate) values. In presence of rhamnolipid, maximum $\mu$ values shifted from around pH 5 which showed maximum enhancement of solubility in the abiotic experiment, compared to the $\mu$ values obtained without the biosurfactant. In this study, the increase in the observed specific grow rate(1.44 times) was not as high as the increase in solubilization(5 times). This was supported by the fact all the solubilized phenanthrene is not bioavailable to microorganisms.