• The Korean Journal of Physiology and Pharmacology
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• v.21 no.2
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• pp.233-239
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• 2017

Intracellular calcium ($Ca^{2+}$) oscillation is an initial event in digestive enzyme secretion of pancreatic acinar cells. Reactive oxygen species are known to be associated with a variety of oxidative stress-induced cellular disorders including pancreatitis. In this study, we investigated the effect of hydrogen peroxide ($H_2O_2$) on intracellular $Ca^{2+}$ accumulation in mouse pancreatic acinar cells. Perfusion of $H_2O_2$ at $300{\mu}M$ resulted in additional elevation of intracellular $Ca^{2+}$ levels and termination of oscillatory $Ca^{2+}$ signals induced by carbamylcholine (CCh) in the presence of normal extracellular $Ca^{2+}$. Antioxidants, catalase or DTT, completely prevented $H_2O_2$-induced additional $Ca^{2+}$ increase and termination of $Ca^{2+}$ oscillation. In $Ca^{2+}$-free medium, $H_2O_2$ still enhanced CCh-induced intracellular $Ca^{2+}$ levels and thapsigargin (TG) mimicked $H_2O_2$-induced cytosolic $Ca^{2+}$ increase. Furthermore, $H_2O_2$-induced elevation of intracellular $Ca^{2+}$ levels was abolished under sarco/endoplasmic reticulum $Ca^{2+}$ ATPase-inactivated condition by TG pretreatment with CCh. $H_2O_2$ at $300{\mu}M$ failed to affect store-operated $Ca^{2+}$ entry or $Ca^{2+}$ extrusion through plasma membrane. Additionally, ruthenium red, a mitochondrial $Ca^{2+}$ uniporter blocker, failed to attenuate $H_2O_2$-induced intracellular $Ca^{2+}$ elevation. These results provide evidence that excessive generation of $H_2O_2$ in pathological conditions could accumulate intracellular $Ca^{2+}$ by attenuating refilling of internal $Ca^{2+}$ stores rather than by inhibiting $Ca^{2+}$ extrusion to extracellular fluid or enhancing $Ca^{2+}$ mobilization from extracellular medium in mouse pancreatic acinar cells.

• Korean Journal of Environmental Biology
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• v.35 no.2
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• pp.128-133
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• 2017

To determine the optimum water temperature (a temperature which minimizes metabolic activities and stress in fish) for long distance transportation of red-spotted grouper (Epinephelus akaara), by evaluating the behavior, survival and physiological and hematological responses to variable water temperature conditions (9, 12, 15, 18 and $21^{\circ}C$) for 48 hours. Fish exposed to $9^{\circ}C$ died at 48 hours exposure, but those exposed to 12, 15, 18 and $21^{\circ}C$ treatment groups all survived. Fish in the 15, 18 and $21^{\circ}C$ exposure groups exhibited normal swimming, while those exposed to $12^{\circ}C$ were observed to be stationary at the bottom of the tank. The plasma cortisol and glucose concentration were higher in fish exposed to $12^{\circ}C$ than at other temperature conditions. The fish in the 12 and $15^{\circ}C$ groups had significantly higher hematocrit (Ht) and hemoglobin (Hb) than those in the 18 and $21^{\circ}C$ groups (P<0.05). Levels of aspartate aminotransferase (AST), $NH_3$ and osmolality showed a pattern similar to the levels of plasma cortisol, while alanine aminotransferase (ALT) and total protein did not significantly vary among the experimental groups. These results indicate that the optimum water temperature for long distance transportation of the red-spotted grouper is $15^{\circ}C$.

• Journal of Life Science
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• v.18 no.8
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• pp.1173-1176
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• 2008

Individuals who regularly consume excessive quantities of alcohol are at a greater risk of developing various cancers such as esophageal, pharyngeal and lung cancers compared to normal populations if they are deficient in ALDH2 enzyme activity. We evaluated oxidative DNA damage in the liver, brain, and lung tissues of Aldh2 +/+ and Aldh2 -/- mice after they had been subjected to acute ethanol exposure. The 8-hydroxydeoxyguanosine (8-OHdG) level in each tissue was evaluated as a biomarker of oxidative DNA damage. The 8-OHdG level in the liver, brain, and lung tissues was significantly increased following ethanol treatment. In addition, the level of 8-OHdG in the liver and lung tissues was affected by ALDH2 enzyme activity. This result suggests that ALDH2-deficient individuals may be more susceptible than wild-type ALDH2 individuals to ethanol-mediated diseases, including cancer.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.27 no.3
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• pp.205-217
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• 2005

Distraction osteogenesis is a technique of lengthening bone including soft tissue by gradual separation of surgically divided bone surfaces. Although the biomechanical, histological, and ultrastructural changes associated with distraction osteogenesis have been widely described, the molecular mechanisms governing the formation of new bone in distracted bone segments remain largely unclear. However, such information has significant clinical implications because it may enable targeted therapeutic manipulations designed to accelerate osseous regeneration. The purpose of this study was to evaluate the expression of TGF-$\beta$1, IGF-I and bFGF in distraction osteogenesis according to different distraction rates in a rabbit's mandible. When twenty-four adult rabbits underwent open osteotomy between the premolar and mental foramen, an external bilateral distraction device was applied. Latency was allowed for five days before distraction. Three different distraction rates were 0.7 mm/day (A, n=8), 1.4 mm/day (B, n=8) and 2.4 mm/day (C, n=8). The distraction device was activated with the same distraction rhythms of twice a day until 4.9 mm (A & B group) and 8.4 mm (C group) length gains was achieved. The animals were sacrificed at postoperative 3, 7, 14 and 28 days. The bony specimens were stained with H&E for histologic examination, and RT-PCR analysis was done for the identification of the expression of TGF-$\beta$1, IGF-I and bFGF. The results obtained from this study were as follows : The 0.7 mm/day and 1.4 mm/day distraction rate groups were shown to improve regenerative bone formation on radiographic and histologic examination. Also, TGF-$\beta$1, IGF-I and bFGF expression increased in the 0.7 mm/day and 1.4 mm/day distraction rate groups. But the 2.4 mm/day distraction rate group specimen was different with adjacent normal bone and hardly expressed of growth factors. These findings suggest that improved new bone formation in the 0.7 mm/day and 1.4 mm/day distraction rates is associated with enhanced expression of TGF-$\beta$1, IGF-I and bFGF by mechanical tension stress. Additionally, the 0.7 mm/day and 1.4 mm/day distraction rate groups were significantly different from the 2.4 mm/day distraction rate group in the expression of growth factors. According to the above results, it seems possible to apply a distraction rate of up to 1.4 mm/day a day in rabbit's mandible. And further studies are needed to evaluate growth factors of TGF-$\beta$1 and IGF-I, which are excellent in expression.

• Journal of the Korean GEO-environmental Society
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• v.14 no.12
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• pp.23-30
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• 2013

Bearing capacity of pile is governed by only skin friction in frozen ground condition, while it is generally governed both by skin friction and end bearing capacity in typically unfrozen ground condition. Skin friction force, which arises from the interaction between pile and frozen soils, is defined as adfreeze bond strength, and adfreeze bond strength is one of the most important key parameters for design of pile in frozen soils. Many studies have been carried out in order to analyze adfreeze bond strength characteristics over the last fifty years. However, many studies for adfreeze bond strength have been conducted with limited circumstances, since adfreeze bond strength is sensitively affected by various influence factors such as intrinsic material properties, pile surface roughness, and externally imposed testing conditions. In this study, direct shear test is carried out inside of large-scaled freezing chamber in order to analyze the adfreeze bond strength characteristics with varying freezing temperature and normal stress. Also, the relationship between adfreeze bond strength and shear strength of the frozen soil obtained from previous study was analyzed. The coefficient of adfreeze bond strength was evaluated in order to predict adfreeze bond strength based on shear strength, and coefficients suggested from this and previous studies were compared.

• Journal of the Korean GEO-environmental Society
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• v.18 no.3
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• pp.5-14
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• 2017

Experimental study on strength characteristics of frozen soils is necessary for the safety evaluation of design and construction in cold region. The objective of this study is to evaluate the direct shear strength of frozen soils obtained from traditional system (Type-1), system with roller on the upper shear box (Type-2), and system with fixed upper shear box separated from bottom shear box (Type-3). Specimens mixed with sand, silt, and water are frozen to $-5^{\circ}C$, and then direct shear tests are conducted under the normal stress of 5, 10, 25, and 50 kPa. Experimental results show that the upper shear box of Type-1 touches the bottom shear box due to the rotation of the upper shear box. The shear strength obtained from Type-2 is overestimated because the preventing rotation force is added to shear force. Type-3 may acquire the only strength of the specimen, and shear strain at peak shear strength is similar to that at the beginning of vertical displacement occurrence. In addition, internal friction angle and cohesion at both peak and residual stresses in Type-3 are smaller than those of Type-2. This study shows that high strength specimens including frozen soils can be effectively evaluated using improved shear box system such as Type-3.

• Journal of the Korean Geotechnical Society
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• v.18 no.4
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• pp.339-347
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• 2002

An in-situ experiment was performed to evaluate the pullout resistance capacity of chains which is used as a reinforcement of reinforced earth wall. It was also considered that chain was combined with a bar or L-type steel angle by the transverse reinforcement member in the experiment. About 80 pullout tests were peformed with varying the lengths of chain(2.0m, 2.5m, and 3.0m), the combination of each transverse members(chain only, chain＋bar, or chain＋angle), and the vertical placement of reinforcements. In the case that uses a chain only and a chain combined with bar, the maximum displacement was about 150mm and load continuously increased to the ultimate tensile strength of chain, and then tension failure of chains occurred. But in the case of a chain combined with angle, the displacement decreased to about 100mm and so it was expected that this combination can constrain the displacement of chain. On the other hand, comparing the yielding pullout load measured in the field to that calculated by theoretical equation, it is shown that measured values are 1.2~3.0 times greater than those of calculated values according to the length of chain, normal vertical stress, and the combination of chain with transverse members. However, the difference in the increment of yielding pullout load between bar and angle is not clear but it appears almost the same increment. It is expected that chain can be safely used as reinforcements of reinforced earth wall, although a theoretical estimation of the pullout resistance capability of chain is too conservative.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.1
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• pp.57-65
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• 2005

This study was performed to investigate the effects of very low calorie diet (VLCD) using meal replacements that contain the wild grass extracts that are consisted of mainly Samul-tang ingredients on weight reduction and health promotion in the obese women (BMI$\geq$25 kg/$m^2$) for four weeks. Fifty six premenopausal women participated in this experiment. Each subject was either classified as part of the control group (C group, n=28) that consumed 3 regular meals a day or the meal replacement group (MR group, n=28) that consumed 1 regular meal and 2 meal replacements within 600 kcal/day. Anthropometric measurements, body composition, health related factors, and psychological factors were assessed before (the initial) and after (the 4$^{th}$ week) the study. Obesity was significantly decreased after the diet intervention. Anthropometric measurements such as weight, waist and hip circumference, and BMI and body composition such as body fat, and fat mass were significantly decreased in all groups after the diet intervention. Anthropometric measurements and body composition of the MR group were significantly decreased more than those of the C group. Serum total cholesterol was significantly decreased in the MR groups but not in the C group and serum triglyceride concentration was significantly decreased in all groups after the diet intervention. All the biochemical measurements were within normal ranges after the diet intervention. Psychological factors such as stress and depression were significantly decreased in two groups after the diet intervention. Therefore, VLCD using meal replacements is very effective for weight reduction in the obese premenopausal women.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.11
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• pp.1736-1743
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• 2013

The purpose of this study is to investigate the effects of 80% ethanol grape leaf extract (VGLE) and resveratrol (VGLR) from Vitis romaneti on antioxidant of red blood cells (RBC) of rat and efficacy of blood flow improvement in a rat model of topical ferric chloride ($FeCl_3$)-induced carotid artery damage. RBC oxidative hemolysis and plasma lipid peroxidation induced by the aqueous peroxyl radical generator 2,2'-azobis(2-amidinopropane) dihydrochloride were significantly suppressed by VGLE or VGLR in a dose-dependent manner. The $FeCl_3$ treatment seriously damaged the carotid artery: the walls of the artery and blood flow. However, VGLE or VGLR administration has ameliorated the blood flow and suppressed thrombus in blood vessels. These results suggest that VGLE or VGLR ameliorates the oxidative stress of RBC and thrombosis against blood vessel damage.

• Korean Journal of Biological Psychiatry
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• v.18 no.3
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• pp.148-158
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• 2011

Objectives The eye movement (EM) has been reported to play a role in enhancing the retrieval of episodic memories and reducing effects of fearful episodes in the past and worries for the futures. However, it is still unclear in the mechanism of EM in normal subjects. We examined the horizontal eye movement (HEM) effect using an aiding apparatus on mental health indices including negative and positive psychological factors, and psychophysiological measures such as heart rate variability and quantitative electroencepaholography (qEEG) in healthy subjects. Methods Twenty eight healthy subjects were recruited and randomly allocated into two groups : active HEM group and control group. The active HEM group conducted the HEM training with usual stress management audio-intervention using the apparatus inducing eye movement once a day for 14 days. The control group also conducted the same training once a day for 14 days, however, the saccadic eye movement was not included in this training. Psychological measurements, neurocognitive function tests, heart rate variability measurement and qEEG were conducted before and after the training in both groups. Results In the active HEM group, sleep status using Sleep Quality Scale (SQS) positive factors significantly increased after the training. By contrast, scores on the negative items of Psychological Well-Being Scale (PWBS), and negative items of the Life Orientation Test-Revised (LOT-R) were significantly decreased after the training. The percentage of delta amplitude (1-3 Hz) in qEEG significantly decreased after the HEM training. The percentage of alpha amplitude (8-12 Hz) significantly increased after HEM training. The change of delta amplitude in the active HEM group was positively correlated with the change of sleep satisfaction of Visual Analogue Scale (VAS), and the change of alpha amplitude was negatively correlated with depression of VAS, anxiety of VAS and Beck Anxiety Inventory (BAI). Conclusions The HEM training improved sleep quality and well-being, and sense of optimism. The HEM training also increased alpha amplitude and decreased delta amplitude in qEEG. The qEEG changes were well correlated with subjective improvement of mental health indices in healthy subjects. These results suggest some evidences that HEM training using the apparatus that induces EM would be helpful in improving subjective mental health in healthy subjects. Further study with larger samples size would be needed.