• Applied Microscopy
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• v.27 no.4
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• pp.433-452
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• 1997

Mongolian gerbil (Meriones unguiculatus) has been as an animal model for studing the neurological diseases such as stroke and epilepsy because of the congenital incompleteries in Willis circle, as well as the investigation of water metabolism because of the long time-survival in the condition of water-deprived desert condition, compared with other species animals. In order to accomplish the this research, first of all another divided the laboratory animals 5 groups of which each group include the 5 animals. In this study were investigated the histological structure in the kidney, measured the plasma osmolalities at the time of sacrifice of indivisual animals, and the body weights every day during water-deprived. The results obtained in this study were summarized as followings: 1. The body weights and decreasing rates of the body weight in water-deprived mongolian gerbil groups were continuosly decreased. 2. The plasma osmolalities were increased from the 5th water-deprived day, after then the gradually increasing reached nearly its equilibrium state at the 10th water-deprived day. 3. The urine volumes were abruptly decreased from the 2th water-deprived day, after then the gradually decreasing patterns were reached nearly its equilibrium state at the 10th day, and stopped the 11th day. 4. In the light microscopical observation of the kidney, glomerular capillary loop thickening, mesangial matrix increasing, sclerosis, glomerular cystic atrophy, interstitial fibrosis, tubular dilatation, mononuclear interstitial inflammation, interstitial mineralization, and hyperplasia of the collecting duct epithelium in the cortex area, were observed from the 10th water deprived day, and the lesions were gradually severe changed as the time lapse. 5. In the electron microscopical findings of the kidney, the degenerative changes of endothelial cell, podocyte and mesangial cell in glomeruli were initially observed on the 10th water-deprived day as well as the degeneration of microvilli and intracellular organelle in the renal tubules.

• Journal of Food Hygiene and Safety
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• v.13 no.2
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• pp.171-187
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• 1998

Garlic occupies a special position among the many foods of vegetable origin because it is the sole food for Koreans during the their lives. And vitamin A has been ingested by forms of food or additives. Cadmium has been described as one of the most dangerous trace elements in the food and environment of man and livestocks. Since the de novo synthesis of stress proteins can be detected early after exposure to some agents, analysis of cadmium-induced changes in gene expression , ie. alterations in patterns of protein synthesis, may be useful to develop as biomarkers of exposure and damage for food hygiene. He acute and chronic combine effects of cadmium (Cd, CdCl2 20mg/kg), garlic oil(Dds: diallyl disulfide 50mg/kg, 3 times a week) and vitamin A(Ra: retinol acetate 50,000 IU/kg, 3 times a week) on Wistar male rats were evaluated concerning cadmium contents, tissues enzyme activity, HSP expression histopathological and electron microscopical examinations. The results of the study are as follows ; 1. Less cadmium was absorbed through the digestive tracts, but the ratio of contents in tissue were not changed by the simultaneous adminstration of diallyl disufide or retinol acetate. 2. ALT(alanine aminotransferase) , AST(aspartate aminotransferase), glucose, BUN (blood urea nitrogen), creatinine, the key indices of the clinical changes in hepatic and renal function were significantly hanged by the cadmium treatment after 1 week in liver, after 4 weeks in kidney. 3. Histopathological changes in cadmium treated rats were appeared at 8 weeks age treatment in kidneys. Homogenous eosinophilic material was accumulated in cortical and collecting tubular lumens at 16 weeks. Degenerated or necrotized tubular cells were observed in cortex and medulla. Degenerated seminiferous tubules and homogeneous eosinophilic material was seen in interstitial tissue of rat treated with cadmium for 16 weeks. Calcium deposits were seen in degenerated seminiferous tubules and the tubules showed severe calcification of rat treated with cadmium for 16 weeks. Electron microscope changes in kidney were observed in rats treated with CdCl2 20 mg/kg. Proximal convoluted tubule cells showed selling of cytoplasm and narrow lumen. Capillary endothelial cells showed cytoplasmic vacuoles and swelling. Degenerated epithelial cells were accumulated in tubular lumen of kidney. 4. Enhanced synthesis of 70 KDa relateve molecular mass proteins were detected in 2 hours after cadmium, exposure, with maximum activity occurring at 8~48 hours. Induction of HSP 70 was evident at proximal tubules and glomeruli in kidney. Testicular cells produced enough HSP to be detected normally. From the above results, it could be concluded that HSP70 induction by the cadmium treatment was a rapid reaction to indicated the exposure of xenobiotics, and retinol acetate reduced the cadmium induced nephrotoxicity.

• Applied Chemistry for Engineering
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• v.18 no.6
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• pp.643-649
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• 2007

Lipase-catalyzed esterification of structural butanol isomers and n-butyric acid was investigated in supercritical carbon dioxide. The experiments were performed in a high pressure cell for 5 hrs with a stirring rate of 150 rpm at 323.15 K and 130 bar. The Candida Antarctica lipase B (CALB) was used in whole system as a catalyst. The experimental results were analyzed by GC-FID using a INNOWax capillary column. The conversion yield and the tendency of the esterification in supercritical carbon dioxide were compared with estimated results by molecular dynamics simulation. Based on the Ping-Pong Bi-Bi mechanism with competitive inhibition, each step of the reaction was optimized; using this result the transition state was predicted. Conformational preference of isomers was also analyzed using molecular dynamics simulations. This kind of approach will be further extended to the prediction of enzyme-catalyzed reactions using computers.

• Korean Journal of Food Science and Technology
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• v.21 no.6
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• pp.815-819
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• 1989

Rheological properties of chestnut starch suspensions (3 and 4%, db) and gelatinized starch (4%, db) were investigated with a capillary and rotational viscometer, respectively. Starch suspensions had no yield stress and showed dilatant flow behavior in the temperature ranges of $30-65^{\circ}C$. However, starch suspension showed pseudoplastic flow behavior at $70^{\circ}C\; and\;above\; 65^{\circ}C$ for 3 and 4% concentration, respectively Flow activation energy below $50^{\circ}C$ was 0.56 kcal/mole but increased to 51.9-80.8 kcal/mole at $60-70^{\circ}C$. The behavior of gelatinized starch (4%) was pseudoplastic regardless of heating temperature $(65-80^{\circ}C)$ and time (15-60 min). The apparent viscosity of the starch remained constant after heating at $80^{\circ}C$ for 45 min. The swelling power and log apparent viscosity showed similar pattern. The activation energy of the apparent viscosity of the geletinized starch at $70-80^{\circ}C$ was 13.09kcal/mole. The apparent viscosity of thermal-gelatinized $(90^{\circ}C)$ starch was lower than that of 15 psi-gelatinized starch.

• Korean Journal of Environmental Agriculture
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• v.34 no.4
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• pp.309-317
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• 2015

BACKGROUND: An analytical method was developed using GC-ECD/MS to precisely determine the residue of fipronil, a phenylpyrazole insecticide used to control a wide range of foliar and soil-borne pests.METHOD AND RESULTS: Fipronil residue was extracted with acetone from representative samples of five raw products which comprised hulled rice, soybean, Kimchi cabbage, green pepper, and apple. The extract was diluted with saline water, and fipronil was partitioned into n-hexane/dichloromethane (20/80, v/v) to remove polar co-extractives in the aqueous phase. Florisil column chromatography was additionally employed for final purification of the extract. Fipronil was separated and quantitated by GC-ECD using a DB-17 capillary column. Accuracy of the proposed method was validated by the recovery from crop samples fortified with fipronil at 3 levels per crop in each triplication.CONCLUSION: Mean recoveries ranged from 86.6% to 106.0% in five representative agricultural commodities. The coefficients of variation were less than 10%. Limit of quantitation of fipronil was 0.004 mg/kg as verified by the recovery experiment. A confirmatory technique using GC/MS with selected-ion monitoring was also provided to clearly identify the suspected residue. Therefore, this analytical method was reproducible and sensitive enough to determine the residue of fipronil in agricultural commodities.

• Applied Chemistry for Engineering
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• v.7 no.6
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• pp.1043-1052
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• 1996

Supercritical fluid chromatographic method was recommended as an alternative separation method of fatty acids of the conventional method such as distillation or extraction. Although diffusion characteristics are varied by the carbon numbers and the degree of unsaturation of fatty acids, the quantitative data were so rare that the commercialization of supercritical fluid chromatographic method has been hindered. In this study, diffusion coefficients of fatty acids which are differently unsaturated are measured by CPB method in the range of 308.15K to 328.15K and 13MPa to 17MPa in supercritical carbon dioxide. A decrease in the binary diffusion coefficient was observed with an increase in temperature and pressure. Also, the decrease in the binary diffusion coefficient with increasing fluid density and viscosity. Wilke-Chang equation, Funazukuri empirical equation, and Matthews-Akgerman equation are used to correlate the experimental diffusion coefficients of fatty acids in supercritical carbon dioxide. Among the various theoretical equations, Matthews-Akgerman equation based on RHS theory was suggested as a more successful correlation model with experimental data.

• Korean Journal of Food Science and Technology
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• v.30 no.1
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• pp.6-12
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• 1998

Degummed and bleached soybean oil was deodorized at a temperature range of $220{\sim}280^{\circ}C$ under the vacuum (4-5 torr) for 1 or 2 hrs. Gas chromatography with SP-2560 100 m capillary column was used to separate and quantitate fatty acid methyl esters and their isomers. Fatty acids were identified by comparing retention time with standards and GC-MS spectrum. The isomers of linoleic acid and linolenic acid in deodorized soybean oils were identified to be $C_{18:2}\;{\Delta}9-cis,\;{\Delta}12-trans,\;C_{18:2}\;{\Delta}9-trans,\;{\Delta}12-cis,\;C_{18:2}\;{\Delta}9-cis,\;{\Delta}12-cis,\;C_{18:3}\;{\Delta}9-cis,\;{\Delta}12-cis,\;{\Delta}15-trans,\;C_{18:3}\;{\Delta}9-trans,\;{\Delta}12-cis,\;{\Delta}15-cis,\;C_{18:3}\;{\Delta}9-cis,\;{\Delta}12-trans,\;{\Delta}15-cis,\;and\;C_{18:3}\;{\Delta}9-cis,\;{\Delta}12-cis,\;{\Delta}15-cis$. The formation of trans-fatty acids by deodorization at $240{\sim}280^{\circ}C$ for 2 hrs was in the range of 1.78 to 5.74%. Conclusively, the deodorizing conditions of $240^{\circ}C$ for 2 hrs or $250^{\circ}C$ for 1 hr were suggested as the best conditions which could minimize the formation of trans isomers of fatty acids in soybean oils.

• Tuberculosis and Respiratory Diseases
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• v.59 no.5
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• pp.551-555
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• 2005

Hemangiopericytoma is a rare neoplasm that originates from small peri-capillary spindle shaped cells called pericytes. The most common sites of origin are the thigh, the pelvis and the retroperitoneum. A primary pulmonary hemangiopericytoma is particularly unusual. However, more than 50% of hemangiopericytoma cases metastasize to the lungs, the bone, and the liver. A long-term clinical and radiological follow up is recommended due to the high risk of recurrence of a potential malignancy. We report a case of a metastatic hemangiopericytoma in the lung that had initially developed in the thigh of a 53 year-old woman 6 years ago. The authors emphasize the long-term follow-up of this type of rare sarcoma.

• The Journal of the Korean bone and joint tumor society
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• v.8 no.3
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• pp.76-82
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• 2002

Purpose: Benign bone tumor of the talar body have rarely been evaluated according to the therapeutic methods because of the scarcity of their incidence. Here, we report our experience of 8 cases who were treated by using of posterior approach and curettage through the posterior process of the talus. Materials and Methods: Between February 1986 and October 2001, we experienced 8 cases of benign bone tumor occurring in the talar body. They included two osteoid osteomas, two giant cell tumors, one capillary hemangioma, one chondroblastoma, one simple bone cyst, and one osteochondroma. Their mean age was 22.1 years (ranging from 10 to 41 years). Mean follow-up period was 7.7 years (ranging from 1 to 16 years). All patients were treated by using of posterior approach. Two osteoid osteomas and one osteochondroma were treated by excision of tumors. Other cases were treated with curettage through the cortical window on the posterior process of the talus. Results: There was no recurrence during the follow-up period. one infection occurred. Except this case, all patients had no pain in weight-bearing, and complete range of movement at the ankle joint was reserved in each case. Conclusion: In this study, we suppose that posterior approach to the talar body may be a safe method with minimal damage of normal tissues and sufficient of curettage is capable through the cortical window on the posterior process of the talus.

• Polymer(Korea)
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• v.35 no.1
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• pp.23-29
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• 2011

We measured shear viscosity of polymeric particles, prepared by suspension polymerization with hydrophobic silica as a stabilizer at $75^{\circ}C$, by a capillary rheometer. Shear viscosity displayed a non-Newtonian behavior with an increase in weight average molecular weight. Measurement of shear viscosity at 170 and $190^{\circ}C$ with copoly(styrene/butyl methacrylate) (co-PSB) particles by varying the ratio between styrene (St) and butyl methacrylate (BMA) showed that shear viscosity was a function of molecular weight, temperature and compositional ratio. When the ratio was 7/3, 5/5 and 3/7, shear viscosity slightly reduced with an increase in BMA concentration despite similar weight average molecular weights. We found that shear viscosity of copolymers with BMA concentrations exceeding 70% displayed a sharp reduction at high shear rates. It is speculated that increased PBMA chain length contributes to enhanced flowability of copolymers. When carbon black was incorporated into co-PSB, shear viscosity progressively increased with increasing carbon black concentration. The increase in shear viscosity, however, was less pronounced compared to the cases of molecular weight increase.