• Journal of Korean Society on Water Environment
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• v.29 no.2
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• pp.196-203
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• 2013

Seungchon Weir was constructed in 2010 on the downstream region of Yeongsan River watershed for four major river projects. The purpose of our study was to determine whether fish compositions and distributions differ between the upper ($U_w$) and lower regions ($L_w$) of Seungchon Weir during May - December 2011 along with hydroacoustic fish surveys using Eco-Sounder monitoring ($E_SM$) technique. Total number of fish species sampled by conventional fish sampling at all sites was 29, and 21 and 24 species occurred in the $U_w$ and $L_w$, respectively. Most dominant species was Hemiculter eigenmanni (43%) in the $U_w$ and Opsaiichthys uncirostris amurensis (21%) in the $L_w$, indicating a distinct differences of the species composition. According to hydroacoustic approach of ESM, fish density was significantly higher (p < 0.05) in the $L_w$ section of 250 m than any other sections, This outcome indicates that fishes moving toward the upstream were blocked by weir construction. According to analysis of tolerance guilds, tolerant species (TS) were made of 88% and 79% in the $U_w$ and $L_w$ region, respectively, while the proportions of sensitive species were < 0.1% of the total in the both regions. Trophic guild analysis showed that the proportion of omnivore species were 58% and 40% in the $U_w$ and $L_w$ region, respectively, while insectivores were made of 16% and 21% in the $U_w$ and $L_w$ region, respectively. Both analyses of tolerance guilds and trophic guilds indicate the biological degradation of the waterbody. Fish community structure analysis, based on species diversity, dominance, and evenness indices, showed higher community stability in the $L_w$ region than $U_w$ region. Exotic species of largemouth bass were largely increased in this survey (14%), compared to the past (< 1%), indicating a modification of fish trophic structure.

• Restorative Dentistry and Endodontics
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• v.24 no.1
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• pp.88-99
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• 1999

The purpose of this study was to investigate the physical properties of experimental composite resins made with the spherical and crushed fillers. The 14 experimental composite resins containing 0, 5, 10, 15, 20 and 25%(w/w) in spherical filler group and 0, 10, 20, 30, 40, 50, 60 and 70%(w/w) in crushed filler group, incorporated in a Bis-GMA matrix (Aldrich Co., USA), were made with 1% ${\gamma}$-methoxy silane treated fillers. The polymer matrix was made by dissolving 0.7%(w/w) of benzoyl peroxide(Janssen Chemical Co. Japan) in methacrylate monomer, whereupon 0.7%(v/v) N,N-dimethyl-p-toluidine(Tokyo Kasei Co. Japan) was added to the monomer. The weight percentage of each specific particle size distribution could be determined from a knowledge of the specific gravity, the weight(w/w), and corresponding volume %(v/v) of the filler sample in resin monomer. In crushed silica group and spherical silica group, the diametral tensile strengths and compressive strengths were measured with Instron Testing Machine(No.4467), and analyzed in 14 experimental composite resins made by filler fractions. The shear bond strength of 14 experimental composite resins to bovine enamel was measured with universal testing machine(Instron No.4467). The fracture surfaces were sputter-coated with a gold film and investigated by SEM. The results were as follows; 1. The diametral tensile strength was tendency to increase in crushed silica group, but not in spherical silica group. The highest diametral tensile strength was found in 20% filler fractions of two groups. 2. The compressive strength was higher in 15%(w/w) and 20%(w/w) in spherical silica group than in crushed silica group, but not in spherical silica group. 3. The significant correlation was noticed in increase in shear bond strength in crushed silica group, but not in spherical silica group. 4. The significantly highest shear bond strength was noticed in 50% filler concentration in crushed silica group, and in 15% filler concentration in spherical silica group, it was not significant in relation. 5. In crushed silica group, cut surface of resin matrix and the interface between resin and filler is obvious. In spherical silica group, fractures that occurred through the filler particles were round in shape.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.9
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• pp.1268-1273
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• 2011

The present study was conducted to determine a feasible method of protein concentrate extraction from rice bran (RBPC) and its effect as a substitution for skim milk in early weaning pig diets. An investigation to extract protein concentrate from full fat rice bran was undertaken to determine the best ratio of water and rice bran, the amount of NaOH and a HCl solvent to use in a simple paddle-type mixer with modified spinning to produce RBPC. The results stated that the best ratio for water mixing in the RBPC extraction process was 1:5 with 20 g NaOH and 30 min in a paddle-type mixer at 300 rpm. A mix of 250 ml 0.2 N HCl was optimum for neutralization and protein precipitation. After the fluid was spun out with a washing machine, the sediment was left for 12-14 hours to complete the filtration. One kilogram of rice bran could produce an average of 324.5 gram RBPC and it contained 3.40% ash, 496.48 kcal of GE/100 gram, 1.94% crude fiber, 28.20% ether extract, 7.64% moisture and 16.66% crude protein, respectively. A total of 45 crossbred piglets, weaned at 3 weeks of age were allotted into control diet (A) and dietary treatments formulated with a four different rates of RBPC substitution for skim milk at a percentage of 25 (B), 50 (C), 77 (D) and 100 (E) respectively, in a randomized complete block (RCB) design. All piglets had free access to feed and water until 8 week of age when the experiment ended. Feed intake, average daily gain, growth rate and feed efficiency were not affected by dietary treatments. Blood test parameters after completion of the growth trial indicated normal health. Even though the mean of cell hemoglobin concentration was significantly different between treatments (p<0.05) it was still within the normal range. The cost difference for BW gain of 100% RBPC substituted for skim milk in the weaning diet was approximately 35% lower than that of the control and the relative cost of production was 96.67, 92.85, 70.75 and 64.48% lower for the replacement of 25, 50, 75 and 100% of skim milk respectively. These results implied that this technology is feasible for use by small scale farmers to improve their self-reliance.

• Journal of Korean Neurosurgical Society
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• v.29 no.8
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• pp.1008-1018
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• 2000

Objective : Glutamate induced excitotoxicity is one of the leading causes of cell death under pathologic condition. However, there is controversy whether excitotoxicity may also participate in the neuronal death under low intensity insult such as simple hypoxia or hypoglycemia. To investigate the role of NMDA receptor in low intensity insult, we chose anoxia as the method of injury and used organotypically cultured hippocampal slice as the material of experiment. Materials & Methods : The hippocampal slices cultured for 2-3 weeks were exposed to 60 minutes of complete oxygen deprivation(anoxia). Neuronal death was assessed with Sytox stain. Corrected optical density of fluorescence in gray scale, used as cellular death indicator, was obtained from pictures taken at 24 and 48 hours following the insult. The well-known in vivo phenomenon of regional difference in susceptibility of hippocampal sub-fields to ischemic insult was reproduced in HOSC(hippocampal organotypic slice culture) by complete oxygen deprivation injury. Results : $CA_1$ was the most vulnerable to complete oxygen deprivation in hippocampus while $CA_3$ was resistant. Oxygen deprivation for 10 and 20 minutes with glucose(6.5g/l) present was insufficient to induce neuronal death in the cultured hippocampal slice. However, after 30 minutes exposure under anoxic condition, neuronal death was able to be detected in the center of $CA_1$ area. The intensity and area of fluorescence indicating cell death correlated with the duration of oxygen deprivation. NMDA receptor and non-NMDA receptor blocking with MK-801(30 & $60{\mu}M$) and CNQX($100{\mu}M$) did not provide cellular protection to HOSC against damage induced by oxygen deprivation, but increased intracellular calcium buffering capacity with BAPTA-AM($10{\mu}M$) was effective in preventing neuronal death (p=0.01, Student's t-test). Cycloheximide($1{\mu}g/ml$, $10{\mu}g/ml$) provided no protection to HOSC against insult of complete oxygen deprivation for 60 minutes and combined therapy of MK-801(30 & $60{\mu}M$) and cycloheximide(1 & $10{\mu}g/ml$) was also ineffective in preventing neuronal death. Conclusion : The results of this study show that the another mechanism not associated with glutamate receptor(NMDA & non NMDA) may play major role in cell death mechanisms induced by complete oxygen deprivation and increased intracellular calcium during anoxia may participate in the neuronal death mechanism of oxygen deprivation. Further investigation of the calcium entry channel activated during oxygen deprivation is necessary to understand the neuronal death of anoxia.

• Ocean and Polar Research
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• v.30 no.4
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• pp.453-466
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• 2008

In order to examine the generation mechanism of long ocean waves along the west coast of Korea and to understand the amplification process of the long ocean waves, sea level, atmospheric pressure and wind data observed every minute from 2007 March 29 to 2007 April 1 were analyzed and onedimensional numerical ocean model experiments were performed. An atmospheric pressure jump propagated southeastward from Backryungdo to Yeonggwang along the west coast of Korea with speed of $13{\sim}27\;m/s$ between 2007 March 30 23:00 and 2007 April 1 1:30. Average magnitude of pressure jump was 4.2 hPa. As a moving atmospheric jump propagated from north to south along the coast, long ocean waves were generated and the sea level abnormally rose or fell at Anheung, Kunsan, Wido and Yeonggwang. Average amplitude of sea level rise (or fall) was about 113.6 cm. In a one-dimensional numerical ocean model, nonlinear shallow water equations were numerically integrated and a moving atmospheric pressure jump with traveling speed of 24 m/s was used as an external force. While the atmospheric pressure jump travels over 60 m depth ocean, a long ocean wave is generated. Because the propagation speed of the atmospheric jump is almost equal to that of the long ocean wave, Proudman resonance occurs and the long ocean wave amplifies. As the atmospheric pressure jump moves into the coastal area shallower than 60 m, the speed of the long ocean wave decreases and Proudman resonance effect decreases. However, the amplitude of the long ocean wave increases and wave length becomes shorter because of shoaling effect. When the long ocean wave hits the land boundary, amplitude of the long ocean wave drastically amplifies due to reflection. Data analysis and numerical experiments suggest that the southeastward propagation of an atmospheric pressure jump over the shallow ocean, which is a necessary condition for Proudaman resonance, generated the long ocean waves along the west coast of Korea on 2007 March 31 and the ocean waves amplified due to shoaling effect in the coastal area and reflection at the shore.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.3 no.1
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• pp.68-77
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• 1993

To evaluate efficiencies of the local exhaust systems installed in chromiun and nickel eletroplating tanks, specifications of each tank and general performances of the local exhaust systems were measured in 16 electroplating plants from July 3 to November 24, 1992. Airborne concentrations of total chromium, hexa-chromium and nickel were also measured, Most of the local exhaust systems installed in electroplating plants were inadequately designed. Average capture velocities of local exhaust systems in chromium and nickel tanks were 0.45 m/sec and 0.29 m/sec. Average slot velocities in chromium and nickel tanks were 7.30 m/sec and 2.87 m/sec repectively. Both average capture and solt velocities were in noncompliance with the standards recommened by American Conference of Governmental Industrial Hygienists (ACGIH) and National Institute for Occupational Safety and Health (NIOSH), Exhausted air volume was insufficient in all local exhaust systems surveyed. Worker exposure levels to total chromium, hexa-chromium and nickel were $43.0{\mu}g/m^3$, $1.7{\mu}g/m^3$ and $9.3{\mu}g/m^3$, which were below the Korean Standard and U.S. Occupational Health and Safety Administration (OHSA) Permissible Exposure Limit(REL). However, Worker exposure level to hexa-chromium exceeded the NIOSH Recommended Exposure Limit(REL) of $1{\mu}g/m^3$. As the result of Scheffee's multiple comparions, worker exposure levels to all metals were significantly different between two groups by the management state of existing local exhaust systems (p<0.05). However, Difference between a group with local exhaust systems which were poorly managed and another group without local exhaust system was satatistically non-significant.

• Journal of Trauma and Injury
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• v.24 no.1
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• pp.1-6
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• 2011

Purpose: Even though traumatic pancreatic injuries occur in only 0.2% to 4% of all abdominal injuries, the morbidity and the mortality rates associated with pancreatic injuries remain high. The aim of this study was to evaluate the clinical outcomes of traumatic pancreatic injuries and to identify predictors of mortality and morbidity. Methods: We retrospectively reviewed the medical records of 26 consecutive patients with a pancreatic injury who underwent a laparotomy from January 2000 to December 2010. The data collected included demographic data, the mechanism of injury, the initial vital signs, the grade of pancreatic injury, the injury severity score (ISS), the revised trauma score (RTS), the Glasgow Coma Scale (GCS), the number of abbreviated injury scales (AIS), the number of associated injuries, the initial laboratory findings, the amount of blood transfusion, the type of operation, the mortality, the morbidity, and others. Results: The overall mortality rate in our series was 23.0%, and the morbidity rate was 76.9%. Twenty patients (76.9%) had associated injuries to either intra-abdominal organs or extra-abdominal organs. Two patients (7.7%) underwent external drainage, and 18 patients (69.3%) underwent a distal pancreatectomy. Pancreaticoduodenectomies were performed in 6 patients (23.0%). Three patients underwent a re-laparotomy due to anastomosis leakage or postoperative bleeding, and all patients died. The univariate analysis revealed 11 factors (amount of transfusion, AAST grade, re-laparotomy, associated duodenal injury, base excess, APACHE 11 score, type of operation, operation time, RTS, associated colon injury, GCS) to be significantly associated with mortality (p<0.05). Conclusion: Whenever a surgeon manages a patient with traumatic pancreatic injury, the surgeon needs to consider the predictive risk factors. And, if possible, the patient should undergo a proper and meticulous, less invasive surgical procedure.

• Journal of Microbiology and Biotechnology
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• v.15 no.6
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• pp.1286-1298
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• 2005

The genus Paenibacillus is a new group of bacilli separated from the genus Bacillus, and most of species have been isolated from soil. In the present study, we collected 450 spore-forming bacilli from the roots of winter crops, such as barley, wheat, onion, green onion, and Chinese cabbage, which were cultivated in the southern part of Korea. Among these 450 isolates, 104 Paenibacillus-like isolates were selected, based on their colony shape, odor, color, and endospore morphology, and 41 isolates were then finally identified as Paenibacillus spp. by 16S rDNA sequencing. Among the 41 Paenibacillus isolates, 23 were classified as P. polymyxa, a type species of the genus Paenibacillus, based on comparison of the 16S rDNA sequences with those of 32 type strains of the genus Paenibacillus from the GenBank database. Thirty-five isolates among the 41 Paenibacillus isolates exhibited antagonistic activity towards plant fungal and bacterial pathogens, whereas 24 isolates had a significant growth-enhancing effect on cucumber seedlings, when applied to the seeds. An assessment of the root-colonization capacity under gnotobiotic conditions revealed that all 41 isolates were able to colonize cucumber roots without any significant difference. Twenty-one of the Paenibacillus isolates were shown to contain the nifH gene, which is an indicator of $N_{2}$ fixation. However, the other 20 isolates, including the reference strain E681, did not incorporate the nifH gene. To investigate the diversity of the isolates, a BOX-PCR was performed, and the resulting electrophoresis patterns allowed the 41 Paenibacillus isolates to be divided into three groups (Groups A, B, and C). One group included Paenibacillus strains isolated mainly from barley or wheat, whereas the other two groups contained strains isolated from diverse plant samples. Accordingly, the present results showed that the Paenibacillus isolates collected from the rhizosphere of winter crops were diverse in their biological and genetic characteristics, and they are good candidates for further application studies.

• Journal of Biomedical Engineering Research
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• v.24 no.1
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• pp.1-8
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• 2003

The job of long distance driving is likely to be fatiguing and requires long period alertness and attention, which make considerable demands of the driver. Driving fatigue contributes to driver related with accidents and fatalities. In this study, we investigated the relationship between the number of hours of driving and driving fatigue using heart rate variability(HRV) signal. With a more traditional measure of overall variability (standard deviation, mean, spectral values of heart rate). Nonlinear characteristics of HRV signal were analyzed using Approximate Entropy (ApEn) and Poincare plot. Five subjects drive the four passenger vehicle twice. All experiment number was 40. The test route was about 300Km continuous long highway circuit and driving time was about 3 hours. During the driving, measures of electrocardiogram(ECG) were performed at intervals of 30min. HRV signal, derived from the ECG, was analyzed using time, frequency domain parameters and nonlinear characteristic. The significance of differences on the response to driving fatigue was determined by Student's t-test. Differences were considered significant when a p value < 0.05 was observed. In the results, mean heart rate(HRmean) decreased consistently with driving time, standard deviation of RR intervals(SDRR), standard deviation of the successive difference of the RR intervals(SDSD) increased until 90min. Hereafter, they were almost unchanging until the end of the test. Normalized low frequency component $(LF_{norm})$, ratio of low to high frequency component (LF/HF) increased. We used the Approximate Entropy(ApEn), Poincare plot method to describe the nonlinear characteristics of HRV signal. Nonlinear characteristics of HRV signals decreased with driving time. Statistical significant is appeared after 60 min in all parameters.

• Journal of Embryo Transfer
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• v.15 no.3
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• pp.231-236
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• 2000

This study was conducted to examine the effects of exogenous gonadotropins (PMSG+hCG) and an antioxidant (cysteine) on in vitro maturation of bovine follicular oocytes. Cumulus-oocyte complexes (COCs) aspirated from 2 to 5 mm ovarian follicles were cultured for 22 to 24 hours in a modified bovine embryo culture medium (mBECM) supplemented with 3 mg/mL bovine serum albumin, to which PMSG (10 IU/mL) + hCG (10 IU/mL) and/or cysteine (0.6 mM) were added. When examined the expansion of cumulus ce1ls at the end of maturation culture, greater (p<0.05) expansion was found after addition of PMSG+hCG (79 to 96%) to mBECM than after no addition (0%), regardless of the presence or absence of cysteine in the medium. The addition of cysteine did not stimulate cumulus expansion, but a high proportion (92%) of expansion was achieved when COCs were cultured after the addition of PMSG+hCG and cysteine to the medium. No difference in the proportion of oocytes underwent germinal vesicle breakdown (initiation of maturation) was found after the addition of PMSG+hCG and/or cysteine to mBECM. However, nuclear maturation (development to the metaphase-II stage) of oocytes was significantly stimulated by the combined addition of PMSG+hCG and cysteine, compared with no addition. In conclusion, both exogenous gonadotropins and an antioxidant are important for nuclear maturation of bovine immature oocytes and these factors have a cell-specific stimulatory action.