• Korean Journal of Environmental Biology
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• v.36 no.1
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• pp.90-97
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• 2018

This study assessed the effect of ozone to control pathogenic bacteria in inlet water flowing to flounder farms, establishing operational parameters of ozonation at seawater conditions. Hydraulic retention time in a reaction pipeline after ozonation was fixed at 3 minutes in a flow through system. Concentrations of total residual oxidant (TRO) by ozonation were measured according to different ozonation intensities. The oxidant reduction potential (ORP), which is indirect but enables real-time measurement, was measured in relation to TRO values. TRO values were $0.01{\pm}0.01mg\;L^{-1}$ at an ORP range of 320-410 mV, $0.07{\pm}0.02mg\;L^{-1}$ at 600 mV, and $0.16{\pm}0.03mg\;L^{-1}$ at 700 mV. A heterotrophic marine bacteria colony was reduced by 80.6-97.9%, showing the suppression effect of ozonation on total bacteria in inlet water. At an ORP range of 400-500 mV, colonies of heterotrophic marine bacteria, Vibrio spp., and gram negative bacteria were significantly reduced in outlet water from a culture tank with ongrowing flounder (230 g) at a stocking density of $8kg\;m^{-2}$. Especially, Vibrio spp. and gram negative bacteria were seldom found at 400-500 mV. The daily feeding rate was from over 0.7% to total body weight at 300-500 mV, showing better performance than that in the control. The pathogenic bacteria entering the flounder farm were effectively removed when the ORP range to 400 mV or less.

• The Korean Journal of Pharmacology
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• v.18 no.1
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• pp.65-72
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• 1982

It has been known that retinoids are intrinsically of critical importance for control of premalignant epithelial cell differentiation. In the absence of retinoids, normal cellular differentiation and growth does not occur in epithelia such as those of trachea and bronchi. Furthermore, it was also reported that retinoid deficiency enhanced susceptibility to chemical carcinogenesis in the respiratory system, in the bladder, and in the colon of the experimental animal. In 1974, Bollag examined the effects of synthetic retinoids in prevention of development of cancer and demonstrated synthetic retinoids to have more favorable therapeutic index than retinoic acid for causing regression of skin papilloma in mice. Therefore, it was assumed that this anticarcinogenic effect of vitamin A derivatives could be due to modification of the metabolism of the carcinogenic polycyclic hydrocarbon, which must first be activated to exert their effect. Hill and Shih reported that vitamin A compounds and analogs had inhibitory effect on drug metabolizing enzyme from liver and lung tissue of mouse and hamster. Lucy suggested that the chemoprevention effect of vitamin A derivatives is due to reaction with molecular oxygen, and it is possible that inhibition of hydroxybenzpyrene formation is a result of this property. On the other hand, butylated hydroxytoluene which is a potent antioxidant strongly inhibited the formation of mammary tumor induced by dimethylbenranthracene. Also, it was observed that this antioxidant inhibited cancer induction in rats by N-2-fluo-renylacetamide. The purpose of this experiment was to investigate the effect of vitamin A derivatives such as retinoic acid and retinoid on drug-metabolizing enzyme and to determine whether riboflavin tetrabutylate or vitamin E could prevent of modify any changes induced by vitamin A delivatives in the rats. The results obtained were as followings. 1) Body weight was significantly reduced by retinoic acid, but not by retinoid. 2) Retinoic acid markedly increased liver weight while retincid showed no effect on liver weight. Treatment of riboflavin tetrabutylate did not affect retinoic acid-induced change in both body weight and liver weight. 3) Both retinoic acid and retinoid remarkably decreased the activity of aminopyrine demethylase. Pretreatment of riboflavin tetrabutylate, however, prevented inhibitory effect of retinoic acid on the enzyme activity. 4) No significant effect of vitamin E on aminopyrine demethylase was observed in both groups treated with retinoic acid and retinoid.

• Journal of Food Hygiene and Safety
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• v.19 no.3
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• pp.126-131
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• 2004

This study was conducted to investigate of inhibition activity of yuza (Citrus junos) extracts and juice on nitrite scavenging and N-nitrosodimethylamine (NDMA) formation in model system. Yuza juice was separated into organic acid, ascorbate and phenolic portion using sep-pak $C_{18}$ cartridge, respectively. Nitrite scavenging activity and inhibition of NDMA formation from yuza extract has shown higher inhibition with pH of reaction condition lower and amount of added sample more. And peel extract of yuza was higher than those of flesh extract. Nitrite scavenging activity was excellent juice portion rather that 3 portions. Of the 3 portions, it activity was the highest in the organic acid portion, and decreased in the following order; phenolic acid, ascorbate portion. Therefore, organic acid of yuza was suggested to expect effective ihhibitor of NDMA formation.

• Journal of the Korean Institute of Gas
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• v.24 no.3
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• pp.33-39
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• 2020

In general, in a batch reaction process in which products are made using flammable liquids, splash filling is used to clean the walls of the reactor by spraying flammable liquids, which are raw materials used for product, during cleaning of the reactor after work. During this process, mist of flammable liquid is generated, the lower limit of explosion is lowered, and fire·explosion may occur due to discharges caused by various types of complex charges, such as flow charge, collision charge, and ejection charge. Therefore, based on the recent accident case, to identify the risk when working in the form of splash filling with toluene in a batch process and perform an explosion impact analysis using the TNT equivalent method After that, we will analyze the accident results and suggest preventive measures such as constant purge system, improvement of cleaning method, and use of tantalum to prevent such accident.

• Applied Chemistry for Engineering
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• v.16 no.1
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• pp.45-51
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• 2005

$K^+-{\beta}^{{\prime}{\prime}}-Al_2O_3$ in the $K_2O-Li_2O-Al_2O_3$ ternary system was synthesized using aluminum nitrate solution as a starting material. For the synthesis of pure $K^+-{\beta}^{{\prime}{\prime}}-Al_2O_3$, raw materials with chemical composition of $0.84K_2O{\cdot}0.082Li_2O{\cdot}5.2Al_2O_3$ were mixed in solution state. The effects of dispersant and solution-pH were investigated in minimizing the particle size and on the synthesis of pure $K^+-{\beta}^{{\prime}{\prime}}-Al_2O_3$. Ethanol was used for a dispersant, and $NH_4OH$ solution and nitric acid were added for pH adjustment. The solution pH was increased from 1.0 to 7.5 by 0.5 increments. Each sample was calcined at $1200^{\circ}C$ for 2 h and characterized with X-ray diffraction and particle size analyzer. The pH of solution significantly effected both particle size and phase formation, while the addition of ethanol only effected particle size. The synthesis of pure $K^+-{\beta}^{{\prime}{\prime}}-Al_2O_3$ was favored by addition of nitric acid (for pH control).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.8
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• pp.44-54
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• 2018

Stress and fatigue of the distributor, an equipment of the high-pressure evaporator for the HRSG, were evaluated according to ASME Boiler & Pressure Vessel Code Section VIII Division 2. First, from the results of the piping system analysis model, reaction forces of the tubes connected to the distributor were derived and used as the nozzle load applied to the detailed analysis model of the distributor afterward. Next, the detailed model to analyze the distributor was constructed, the distributor being statically analyzed for the design condition with the steam pressure and the nozzle load. As a result, the maximum stress occurred at the bore of the horizontal nozzle, and the primary membrane stress at the shell and nozzle was found to be less than the allowable. Next, for the transient operating conditions given for the distributor, thermal analysis was performed and the structural analysis was carried out with the steam pressure, nozzle load, and thermal load. Under the transient conditions, the maximum stress occurred at the vertical downcomer nozzle, and of which fatigue life was evaluated. As a result, the cumulative usage factor was less than the allowable and hence the distributor was found to be safe from fatigue failure.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.11
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• pp.1487-1494
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• 2009

The major histocompatibility complex (MHC) plays well-defined roles in eliciting immune responses and combating infectious diseases. The major histocompatibility complex of cattle is referred to as BoLA (Bovine Lymphocyte Antigen). This genetic system is among the most polymorphic. In the present study, polymorphism of the BoLA- DRB3.2 locus in three Bos indicus breeds viz., Sahiwal, Rathi and Hariana was studied by polymerase chain reaction restriction fragment length polymorphism technique using the enzymes RsaI, Bst Y1 and Hae III. Both Sahiwal and Rathi are good Indian dairy breeds and survive under tough tropical conditions, while Hariana is a prominent dual-purpose breed reared both as a dairy animal and for bullock production. A total of 30 different BoLADRB3.2 alleles were observed to be present in the 3 Bos indicus breeds. Certain alleles were common amongst the three breeds while there were others that were unique to each breed. Allelic distribution amongst the three breeds showed that each breed had a unique allelic distribution pattern that was different from each other and also different from the earlier breeds studied so far for the existence of allelic variation at this locus. A dendogram was constructed based on the frequencies of the BoLA-DRB3 alleles using the UPGMA method. The Rathi and Hariana animals were genetically the most apart. The Hariana animals clustered on a different branch from the other two breeds viz. the Rathi and the Sahiwal. The smallest genetic distances for the DRB3 alleles were those between Sahiwal and Rathi (0.5461) while genetic distance between Hariana and Sahiwal was 0.6123. A comparison of the allelic frequencies of the BoLADRB3.2 locus in these 3 breeds viz. Sahiwal, Hariana and Rathi with the allelic frequencies present in the previously characterized Bos indicus Kankrej breed, which is a dual purpose breed reared both as a draught and a dairy animal, showed that the Bos indicus Sahiwal and Rathi breeds clustered into one group while the Hariana and Kankrej breeds formed another group. The Rathi and Sahiwal showed the least genetic distance of 0.5461 amongst the breeds whereas the Rathi and Kankrej, with a Nei''s genetic distance of 1.1622, were genetically the most distant apart.

• Microbiology and Biotechnology Letters
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• v.10 no.4
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• pp.267-273
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• 1982

Among 12 kinds of ginsenosides in ginseng saponin, ginsenoside-Rb$_1$was contained the most abundantly. But ginsenoside-Rd which is similar to ginsenoside-Rb$_1$in structure, was known to be superior to ginsenoside-Rb$_1$pharmaceutically. In order to convert ginsenoside-Rb$_1$into ginsenoside-Rd by microbial enzyme treatment, a Rhizopus sp. was selected among various strais of molds found in rotten ginseng roots. Enzyme was prepared from the extract of wheat bran koji culture by ammonium sulfate precipitation (1.0 sat'd) and succeeding ammonium sulfate fractionation method (0.6-0.9 sat'd). For the purpose of use as substrate, saponins were purified by the several purification steps from alcohol extract of red ginseng roots. We obtained the total saponin which was composed of 36.5% of ginsenoside Rb$_1$, 12.2% of ginsenoside-Rd and other ginsenosides. For increase of ginsenoside-Rb$_1$ component ratio, we also obtained further purified ginsenoside-Rb group saponin containing 54.5% of ginsenoside-Rb$_1$, 1.1% of ginsenoside- Rd and other ginsenosides from purified the total saponin. In the enzymatic reaction system including the total saponin or the ginsenoside-Rb group saponin, we confirmed the specific conversion of ginsenoside-Rb$_1$to ginsenoside-Rd proportionally and no change of any other ginsenoside patterns by thin layer chromatography and high performance liquid chromatography.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.9
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• pp.911-916
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• 2005

In this study, variations of water quality, sediment size and contaminant substances are analyzed at upstream and downstream in sewer systems in order to evaluate the characteristics of wastewater transformation by physico-chemical and biological reactions. The differences of DOC concentration between up and down stream showed the range of $-5.8{\sim}18.6$ from the result of continuous measurement at up and down stream. About 8.4% of DOC concentration was reduced and reduction rate was 2.3 mg/L/km. SS reduction rate was measured by 5.5 mg/L/km, 0.22 mg/L/min from upstream to downstream, which was twice than DOC reduction rate. When pollution load reduction was evaluated considering infiltration/inflow effect, DOC load was eliminated from 1,230 ka/d to 1,167 kg/d by physi-chemical and biological reaction in a sewer and 7.8% of the SS in upstream station was reduced under dry weather condition. The results showed that the characteristics of transformation process of wastewater in sewer should be considered for design and operation of wastewater treatment plant.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.7
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• pp.426-439
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• 2017

This review summarizes advantage and limitation in infrared spectroscopy and computational chemistry to understand rhizospheric interaction among organic acids, oxyanions and metal oxides. Since organic acids and metal oxides determine dynamics of oxyanions in the soil environment, knowledge of fundamental mechanisms is a prerequisite for understanding the interactions at soil-water interface. Attenuated total reflectance-fourier transform infrared spectroscopy (ATR-FTIR) is a powerful tool to measure the interfacial reactions. However, the ATR-FTIR measurements are abstruse, because the optical characteristics for measurements are variable depending on the experimental setup. In addition, spectral overlapping is a primary obstacle to the analysis of the interfacial reaction; thus, it is essential to detect and to deconvolute bands for signal interpretation. In this review, we expained the fundamental principle for spectrum processing, and four band identification methods, such as derivative spectroscopy, two-dimension correlation spectroscopy, multivariate curve resolution, and computational chemistry with example of aqueous phosphate speciation. As a result, spectrum processing and computational chemistry improved interpretation and spectral deconvolution of overlapped spectra in relatively simple systems, but it was still unsatisfactory for the problems in more complexed system like nature. Nevertheless, we believed that our challenge would contribute practically to develop adequate analytical procedure, signal processing and protocols that could help to improve interpretation and to understand the interfacial interactions of oxyanions in natural systems.