• Environmental Analysis Health and Toxicology
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• v.3 no.3_4
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• pp.9-15
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• 1988

The word of stress crime from Latin language as stringere and it was used in medical fields from 1935. According to Selye, all the biological bodies reveal physilolgical changes when some stimulation exceed normal levels, and consequently the pituitary gland and adrenal systems are activated. Jacob expressed that stress is the loss of homeostasis by physical, chemical, and emotional stimulation. When biological organisms receive extreme stress the amount of catecholamine excretion are increase. Author investigated the catecholamine contents in rat urine after giving the low temperature stress, noise stress, and water immersion stress. The 24 hours rat urine was collected by adding 1 ml 6 N-HCl and the sample is passed through Bio-Rex 70 samples treatment column to extract catecholamine and detected the catecholamine with HPLC-fluorescence detetor. The highest epinephrine concentration was 67.14 ng in water immersion stress condition and the dopamine concentration of 221.37 ng was shown in the low temperature stress condition.

• Journal of Nutrition and Health
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• v.28 no.4
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• pp.291-297
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• 1995

This study aimed to verify the nutritional and curative effects of protein hydroysate in rats model with gastric ulcer induced by restraint and water-immersion stress. Sprague-Dawley, famale rats weighing approximtely 200g were forced in 5$\times$5$\times$15cm plexiglas cage. The restraint and water immersion stress was carried at 20$\pm$2$^{\circ}C$ for 8-hours. After stress 4 kinds of diets(10% casein, 20% casein, 10% casein hydrolysate, 20% casein hydrolysate) were given for 5 days. In the gastric ulcer rats model, the growth, gastric emptying rate, trypsin activity in gastrointestinal content, plasma total protein, albumin, $\alpha$-amino-N, UUN, creatinine and hydroxyproline of the urine and nitrogen retention were analyzed for nutritional effects of dietary nitrogen levels(10%, 20%) and sources (casein, casein hydrolysate). The results were as follows ; In gastric ulcer rats model, severeness of ulcer, plasma protein, gastric emptying rate, nitrogen retention rate were not different between 20% casein-fed group and 20% casein hydrolysatefed group. But 10% casein hydrolysate-fed group had more curative group. The casein hydrolysate diet-fed group was lower trysin activity in small intestianl content than the casein-fed group, at both casein level(10%, 20%). Finally at 20% levels, there was no difference between casein and casein hydrolysate diet, but 10% level, casein hydrolysate diet was more curative of ulcer than casein diet in gastric ulcer rat model. The results of this study provide useful information concerning diet therapy for the patients with gastrointestinal diseases and the field of enteral diet materials.

• Geomechanics and Engineering
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• v.38 no.1
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• pp.45-56
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• 2024

The weakening effect of water on rocks is one of the main factors inducing deformation and failure in rock engineering. To clarify this weakening effect, immersion tests and post-immersion triaxial compression tests were conducted on sandstone and mudstone. The results showed that the strength of water-immersed sandstone decreases with increasing immersion time, exhibiting an exponential relationship. Similarly, the strength of water-immersed mudstone decreases with increasing environmental humidity, also following an exponential relationship. Subsequently, a statistical damage model for water-weakened rocks was proposed, changes in elastic modulus to describe the weakening effect of water. The model effectively simulated the stress-strain relationships of water-affected sandstone and mudstone under compression. The R² values between the theoretical and experimental peak values ranged from 0.962 to 0.996, and the MAPE values fell between 3.589% and 9.166%, demonstrating the model's effectiveness and reliability. The damage process of water-saturated rocks corresponds to five stages: compaction stage - no damage, elastic stage - minor damage, crack development stage - rapid damage increase, post-peak residual stage - continuous damage increase, and sliding stage - damage completion. This study provides a foundational reference for researching the fracture characteristics of overlying strata during coal mining under complex hydrogeological conditions.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.6
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• pp.520-523
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• 2000

Anti-ulcer effects of depolymerized alginate (HAG-10, average molecular weight 10,000; HAG-50, average molecular weight 50,000; HAG-100, average molecular weight 100,000) obtained by hydrolysis of alginate by heating at $121^{\circ}C$, against $HCl{\cdot}ethanol$ and water-immersion stress in rats were investigated. The acute gastritis, induced by $HCl{\cdot}ethanol$, and the gastric ulcer, induced by water-immersion stress, were inhibited dose-dependently by administration of HAG-50, HAG-100 and alginate. Histopathological lesions of the gastritis and gastric ulcer in rats treated with HAG-50, HAG-100 and alginate were significantly lower than those in rats fed with HAG-10. The inhibition rates (${\%}$) on acute gastritis induced by $HCl{\cdot}ethanol$ and gastritis ulcer induced by water-immersion stress in rats, were $13.00{\%}\;and\;15.74{\%}$of HAG-10, $41.15{\%}\;and\;35.72{\%}$ of HAG-50, $41.58{\%}\;and\;35.37{\%}$ of HAG-100, and $45.17{\%}\;and\;41.11{\%}$ of alginate, respectively. These results suggested that HAG-50, HAG-100 and slginate had a protective effect against the gastritis and gastric ulcer. The effect was not as visible when using HAG-10 in rats. From the present results, it was suggested that HAG-50 was an effective anti-ulcer agent against $HCl{\cdot}ethanol$and water-immersion stress in rats.

• Journal of the East Asian Society of Dietary Life
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• v.7 no.1
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• pp.13-20
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• 1997

This study was designed to determine the effects of protein sources on the curation of gastric ulceration, protein metabolism, and nitrogen balance in rats with gastric ulcer induce by restraint and water immersion stress. After the rats were fed 10% casein diet for 3 weeks, four groups of the rats were forced in 5$\times$5$\times$15cm plexiglass cage. The restraint and water immersion stress was carried at 20$\pm$2$^{\circ}C$ for 8-hour. The other one group(control group) was not exposed to stress. After stress 4 kinds of different diets containing 20% protein were given for 5 days. The protein sources were casein, whey protein, soy protein, gluten. The control group was fed to 10% casein diet. The results were as follows ; the weights of rats were not different among the diet groups During the experiment period follows ; the weights of rats were not different among the diet groups during the experiment period (for 5 days). The ulcer index of rats fed 10% gluten and soy protein diet was significantly higher than those of casein and whey protein diet groups(p<0.05). The level of serum albumin was not significantly different among diet groups. But hematocrit and the level of $\alpha$-amino-N, BU and UUN of plant protein diet groups were higher than animal diet groups, the urinary hydroxyproline of soy protein group was the highest and the whey protein was the lowest. The digestibility and BV of nitrogen of gluten diet group were significantly higher than those of casein and whey protein diet groups(p<0.05). The animal proteins had more curative effects of ulcer than plant animals. The results of this study provide useful information concerning diet therapy for the patients with gastrointestinal diseases and the field of enteral diet materials.

• Natural Product Sciences
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• v.12 no.3
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• pp.150-152
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• 2006

The ethanol extract of Sida acuta Burm. (ALSA) whole plant was studied for its anti-ulcer activity against aspirin plus pylorous ligation induced gastric ulcer, HCl-ethanol induced ulcer, and water immersion stress induced ulcer (WISIU) in rats. We found that ALSA at a dose of 300 mg/kg, (orally) markedly decrease the incidence of ulcers in the first two models. ALSA showed reduction in gastric volume, free acidity, and ulcer index (53.69%). It has not reduced the total acidity significantly and no significant change in pH. It also showed 55.14% gastro protective activity, wheres standard drug sucralfate showed 94.85%. WISIU showed protection index 24.4%, whereas standard drug omeprazole (OMEZ) showed protection index 100%.

• Korean Journal of Veterinary Research
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• v.44 no.4
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• pp.607-613
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• 2004

Helicobacter pylori (H. pylori)-infection is an important pathogen of stomach cancer after chronic gastritis and ulceration in the stomach and duodenum. However, the virulences of H. pylori strains have not been well-defined between clinical isolates. This study was designed to establish water-immersion-restraint stress (WIRS) model in mongolian gerbil for comparison of pathogenicity of H. pylori strains. To determine an optimal duration time for WIRS model in gerbil, 5-week-old Mongolian gerbils were divided into different groups by WIRS duration time. After graded duration of WIRS, the macroscopic ulcer index (UI) was measured with the stomach and duodenum of sacrificed animal. There were no significant differences between male and female in same duration group. However, the UI increased significantly in a time-dependent fashion. The group of 6 hours-WIRS animals showed severe hemorrhage and ulceration in their stomach and duodenum. On the other hand, the very mild lesions induced in 2 hours-treated animals. Therefore, we determined an optimal duration time for WIRS model in gerbil as 4 hours. Thereafter, we evaluated whether this WIRS model in gerbil could be used as an useful tool for in vivo comparison of pathogenicity of H. pylori strains by enhancement of pathological severity in H. pylori-infected gerbils. Mongolian gerbils were divided into H. pyloriinfected and PBS-inoculated groups. Thereafter, they were divided again into 4 hours-WIRS and no WIRS subgroups. After treatment, the severity of pathological changes was evaluated in a same manner with previous duration-determining experiment. When the animals were exposed to WIRS, the UI was significantly higher in the infected group than in the uninfected group. These results suggested that the established gerbil-WIRS model in this study enhanced effectively the severity of pathogenic changes in the H. pylori-infected Mongolian gerbils and could be used as an useful tool for in vivo comparison of pathogenicity of H. pylori strains.

• Journal of the Korea Institute of Building Construction
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• v.14 no.2
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• pp.170-176
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• 2014

This study examined the effect of chemical attack on the stress-strain relationship of alkali-activated Hwangtoh concrete. Water-to-binder ratio and air content were selected as mixture parameters. The stress-strain relationship of concrete was measured at chemical immersion times of 0, 7, 28, 56, and 91 days from an age of 28 days. Based on the test results, the reduction in compressive strength of alkali-activated hwangtoh concrete owing to chemical attack was formulated. In sddition the present study demonstrated that the stress-strain behavior of concrete under chemical attack is significantly dependent on the air content and chemical immersion time, indicating the rate of decrease of modulus of elasticity was greater than that of compressive strength at the same immersion time. As a result, the stress-strain behavior of concrete under chemical attack was significantly inconsistent with the conventional models specified in the CEB-FIP provision.

• Corrosion Science and Technology
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• v.19 no.3
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• pp.138-145
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• 2020

Immersion tests of Alloy 600 were conducted in simulated primary water environments of a pressurized water reactor at 325 ℃ for 10, 100, and 1000 h to obtain insight into effects of surface deformation on internal and intergranular (IG) oxidation behavior through precise characterization using various microscopic equipment. Oxidized samples after immersion tests were covered with polyhedral and filamentous oxides. It was found that oxides were abundant in mechanically ground (MG) samples the most. The number density of surface oxides increased with time irrespective of the method of surface finish. IG oxidation occurred in mechanically polished (MP) and chemically polished (CP) samples with thin internal oxidation layers. However, IG oxidation was suppressed with relatively thick internal oxidation layers in MG samples compared to MP and CP samples, suggesting that MG treatment could increase resistance to primary water stress corrosion cracking (PWSCC) from the standpoint of IG oxidation. As a result, appropriate surface treatment for Alloy 600 could prevent oxygen diffusion into grain boundaries, inhibit IG oxidation, and finally induce its high PWSCC resistance.

• Journal of Nutrition and Health
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• v.30 no.8
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• pp.920-929
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• 1997

This study examined the effect of dietary salt levels on the incidence and cure of gastric ulcer in rats. Two sets of experiment were conducted . In the first experiment, the rats were divided into 3 groups. The 3 groups were fed 0%, 4%, and 8% NaCl diets respectively for 20days. The rats were given water -immersion restraint stress at the end of the dietary period , and sacrificed. The ulcer index by histological test was higher in rats fed the 8% NaCl diet than those in the other groups. The hexosamine and glutathione levels were significantly lower in the rats fed the 8% NaCl diet. Hematocrit and total iron binding capacity(TIBC) showed lower values caused by bleeding of gastric mucosa. The second experiment was designed to determine the effect of soldium concentration on the cure of gastric ulcer . As the gastric ulcer was recovered, ulcer length was gradually deceased in the control group but not changed in the 8% NaCl diet group. The gastric hexosamine and hepatic glutathione were increased in the control group but decreased in the 8% NaCl diet group. The hematologic indices of stressed rats showed the same tendency. As a result, dietary salt per se did not cause gastric ulcer . Once an ulcer is formed by stress or any other factor, higher levels of dietary salt may be detrimental to gastric mucosa, thereby delaying the healing of the ulcer. It is recommended that dietary salt intake be reduced in stress-prone people.