• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.6
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• pp.699-705
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• 1999

The effects of iron on gill tissue and metabolic rate represented by oxygen consumption of olive flounder, Paralichthys olivaceus were determined. The effects were further studied by means of survival rate of the fish exposed to a serial concentrations of iron. The olive flounder exposed to iron concentrations over 0.93 mg/$\ell$ showed curvature and terminal clubbing of gill lamellae at 2 weeks post-exposure. In iron concentration 4.89 mg/$\ell$, gill of the fish were seriously damaged just after 2 weeks, showing hyperplasia of filament epithelia, deformation of lamella epithelia, chloride cell damage, and separation of lamella epithelial layer, Gills exposed to 9.78 mg/$\ell$ iron concentration resulted in fusion and necrosis of the lamellae after 2 weeks. Significant decreases of metabolic rate of the fish were observed after 4 weeks at iron concentration 0,93 mg/$\ell$ and after 2 weeks at iron concentrations over 4.89 mg/$\ell$. Survival rate of the olive flounder decreased significantly after 4 weeks at the iron concentration over 4.89 mg/$\ell$. These results lead us to conclude that, as far as the iron effects are concerned, its concentrations should not exceed at least more than 0.93 mg/$\ell$ in the fish farm and coastal waters for normal growth of the olive flounder.

• The Journal of Korean Academy of Prosthodontics
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• v.36 no.2
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• pp.323-335
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• 1998

Clinically, the curve of Spee is widely applied as a determined level of the occlusal curvature when the oral rehabilitation and the reconstruction of the prosthesis is needed at the malalignment dentition due to the missing, extrusion, and the inclination of the teeth. The purpose of this study was to analyze the curve of Spee of the occlusal curvature which influences to the occlusal form and the location three dimensionally, and then was to measure the radius and the degree of curvature of the curve of Spee and also was to investigate the influence to the cuspal inclination according to the change of the inclination of the curve of Spee which was analyzed by AutoCAD R.13 program at the gnathological cast and the cephalometric radiograph. The following results were obtained : 1. The radius of the curve of Spee was the mean of $11.74{\pm}3.64cm$ in the model, $12.75{\pm}4.63cm$ in the radiograph and there was no significant difference statistically between the model and the radiograph(P>0.001). 2. The radius and the degree of curvature of the curve of Spee showed negative correlation(r=-0.80), while the radius and the degree of curvature of the curve of Spee in relation to the length of the curve of Spee did not show correlation. 3. The case of the curve of Spee inclined to the posterior, that is. $Post.M{\theta}$ group showed the mean of $4.73{\pm}3.64$, positive correlation to the P2m, M1mm, M1dm, M2dm, and especially the greatest correlation coefficient to the mesial inclination angle of the mesio-buccal cusp tip of the first molar(r=0.70). 4. The case of the curve of Spee inclined to the anterior, that is, $Ant.M{\theta}$ group showed the mean of $3.28{\pm}3.59$, positive correlation to the P2m, M1mm, and also the greatest correlation coefficient to the mesial inclination angle of the mesio-buccal cusp tip of the first molar(r=0.78

• The Journal of Engineering Geology
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• v.10 no.2
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• pp.52-74
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• 2000

The basement rock of upper stream of Keum River Valley consists of Precambrian gneiss which is resistant to weathering. That of mid and lower stream valley, however, is mainly composed of Mesozoic granites which are vulnerable to weathering. The upstream part of Geum River Basin is typified by the deeply-incised and steep meandering streams, whereas mid and lower part is characterized by wide floodplain and gently dipping river bottom toward the Yellow Sea. In particular flooding deposits, in which are imprinted a number of repetitions of erosion and sedimentation during the Holocene, are widely distributed in the lower stream of Geum River Basin. For understanding of erosions in the mid and lower stream of Geum River Basin, the rate of erosion of each small basins were estimated by using the data of field survey, erosional experiments and GIS ananlysis. It was revealed that erosion rate appeared highest in granite areas, and overall areas, in this field survey were represented by relatively high erosion rates. By implemeatation of remote sensing and imagery data, the temporal changes of river bed sediments for about last 11 years were successfully monitored. Observed as an important phenomenon is that the river bed has been risen since 1994 when an embankment (Dyke) was constructed in the estuarine river mouth. From the results derived from the detailed river bed topographical map made in this investigation, the sedimentation of the lower river basin is considered to be deposited with about 5 cm/year for the last 11 years. Based on this river bed profile analysis by HEC-6 module, it is predicted that Geum River bed of Ganggyeong area is continuously rising up in general until 2004. Although extraction of a large amount of aggregates from Gongju to Ganggyung areas, the Ganggyung lower stream shows the distinct sedimentation. Therefore, it is interpreted that the active erosions of tributary basins Geum drainage basins can affect general river bed rising changes of Geum River.

• Journal of Plant Biotechnology
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• v.44 no.3
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• pp.320-324
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• 2017

Development of modern agricultural machinery and accompanying agricultural development cause soil compaction and reduce growth by stressing roots. Kalanchoe pinnata was used to investigate the impact of stress on rooting and changes in plant growth and reproduction. K. pinnata forms somatic embryos capable of asexual reproduction at the edge of leaves. Impact of root pressurization of K. pinnata on somatic embryogenesis and organ differentiation according to external stress factors was investigated by using a high concentration of agar and this phenomenon was studied histologically. Agar concentration in culture media ranged from 0.5%-1.5% to induce a compression effect on roots. The stem and leaf of K. pinnata were subjected to a microtechnique process to study changes in tissue. In vivo, K. pinnata produced 2nd and 3rd plantlets at edges of leaves from lack of water and excessive lighting conditions. In in vitro culture studies, the lower the concentration of agar, the higher the population and the higher the biomass, but plantlet did not occur in leaf bends. Conversely, as concentration of agar increased, increase in the number of individuals was low. Plantlet development occurred only in agar 1.5% medium. The difference in agar concentration was a stressor in the root of K. pinnata, and thus the pattern of asexual reproduction changed from the division method in root to a plantlet generation in leaf. This suggests root pressurization may act as stress and change in the plant reproduction pattern.

• Journal of Korea Water Resources Association
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• v.49 no.8
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• pp.693-705
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• 2016

In this study, the effects of sediment supply on the downstream of a large dam are investigated using a numerical model. The model simulation shows a good agreement with laboratory experiment results of sediment transport and diffusion from sediment pulses. The water surface changes from the various sediment bed elevations are also simulated using the model. The site which has a relatively stiff bed slope and meandering of a channel is selected as an appropriate location for sediment supply because of its shear stress enough to supply the sediment downstream. The model simulation shows the decrease of channel bed elevation through the simulation period with time. The well-deposition of sediment supplied from the downstream of dam is found in the location where the flow rate is relatively low. A bed relief index is increased with time and it is relatively greater in downstream compared to upstream. The channel bed variability increases as flow rate increases with a greater bed relief index. The results of this study demonstrate the importance of increasing water discharge of a large dam to increase the dynamic of channel bed and thus to enhance the efficiency of channel bed restoration by sediment supply.

• Restorative Dentistry and Endodontics
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• v.30 no.3
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• pp.184-192
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• 2005

Intracanal separation of the rotary files is a serious concern in modern endodontic practice. The objective of this study was to compare the life span and fracture patterns of three NiTi rotary files in molar teeth Mesiobuccal roots of upper molar (n = 150) and mesial roots of lower molar (n = 150) were divided into three groups and each group was prepared with Profile, ProTaper, and K3 respectively. Every file was used until separation and/or deterioration of the cutting blade was happened, and then the number of canals to separation and/or unwinding were recorded. Radiographs and Scanning electon microscope (SEM) photographs were taken to evaluate the patterns of separation. The results were as follows: 1. There were no significant differences in numbers of canals to separation and/or unwinding among the groups. 2. Comparing between flaring files, K3 showed significant lower numbers of canals to separation and/or unwinding (p < 0.05), and there was no significant difference between shaping files 3. Separations of instruments were occurred at the midpoint of curvatures within the canals 4. In SEM observations, ductile fractures were seen in most of cases, characterized by shallow dimples. Additional researches is needed to provide a new guideline that informs the appropriate number of times to use NiTi files.

• Physical Therapy Korea
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• v.5 no.3
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• pp.72-87
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• 1998

This study examined the rates of spinal abnormal curvature and the correlation of the Body Mass Index (BMI), Low Back Pain (LBP) and spinal curvature by measuring scoliosis, kyphosis, and lordosis in university students. The study population included 67 male, 92 female university students, making a total of 159, in Wonju City. Spinal curvature was measured by an electrogoniometer in a computerized skeletal analysis system. Lateral curvature of spine of more than 10 degrees was considered as nonspostural scoliosis. The correlation of BMI, LBP and the spinal curvature was analysed by Pearson's correlation coefficient and t-test. The following results were obtained: 1. The overall incidence and rate of scoliosis in cases with a greater than 10 degree curve in males was an incidence of 8 and a rate of 11%. In females the incidence was 36 and the rate 39.2%. 2. The overall incidence and rate of kyphosis of less than 20 degrees in males was a rate of 9 and an incidence of 11.9%. In females, the rate was 5 and the incidence 5.4%. In kyphosis cases of more than 40 degrees, the male rate was 5 and the incidence 7.7%. For female the rate was 13 and the incidence 14.2%. 3. The overall incidence and rate of lordosis with curves of less than 20 degrees was a rate of 6 for males and an incidence of 9.0%. For females, the rate was 5 and the incidence 5.4%. In cases of more than 50 degrees lordosis, the female rate was 2 and the incidence 2.2%. There were no males in this category. 4. There was a negative correlation between kyphosis and BMI. The greater the kyphotic curve, the less the BMI in males (p<0.05). There was no significant BMI difference by gender in either scoliosis or lordosis. There was, however, a significantly decreased sacral angle in the female group with LBP. The results of this study cannot be generalized to the general population because the subjects were all from one university. The measurements were quite reliable because the angles determined by the Metrocom System were highly correlated with radiologic findings. This study shows the need for a regular screening system for spinal curvatures in university health examination procedures.

• Restorative Dentistry and Endodontics
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• v.26 no.5
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• pp.418-435
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• 2001

Root canal preparation process is of utmost importance in successful treatment of root canal. Also, one of the most important purpose of the root canal preparation is to enlarge the root canal three dimensionally without changing the curvature of the root canal However as the curvature of the root canal increases, there are many difficulties involved in formation of optimum root canal. Therefore in order to solve the above mentioned problems, new developments in methods of root canal preparation and equipments for such purposes were made. Recently, vigorous studies about newly introduced engine-driven nickel-ti-tanium rotary file are conducted. As shown in research results to dates, it is well established that the use of nickel-titanium file is better suited for curved root canal than stainless steel file in maintaining the curvature or root canal and reducing the deformation of root canal. However it is also acknowledged that there are a few discrepancies in research results according to protocol, due to failure to remove variables in experiments. In addition, although it is recommended by the manufacturer that the GT rotary file should maintain a low rotational speed of 150~350rpm and 'light pressure' as light as not to break the lead of a pencil, academic studies about the vertical force which is not yet standardized are not sufficiently explored. Therefore, this research devised and utilized a special research equipment to standardize the appropriate range of vertical force for GT rotary file through experiments by breaking of the lead of a pencil as expressed by the manufacturer and to accurately measure factors involved through repeating and recreating the environment of root canal preparation. Forming nine experimental groups by varying the vertical forces (150g. 220g, 300g) and rpm (150rpm, 250rpm, 350rpm), the effects of changing vertical forces and rpm on working efficiency were measured in terms of time expended in root canal preparation by crown-down method using a transparent resin block with 35 degree curvature and GT rotary file (z-test). The following research using this special research equipment that involved nine experimental groups and varying the vertical force for root canal preparation from 300g which is within the normal vertical force range to 700g and 1000g which fall outside the normal rpm range. The results were as follows : 1. Analysis of the experiment results revealed that the time spent in root canal preparation decreased as the vertical forces and rpm increased (p<0.05). Also, the effects of rpm were greater than those of the vertical forces within the normal vertical force range ($\beta$-weight test). 2. Observation of the deformation of GT rotary file revealed that deformation increases in a direct correlation with the vertical force increase and in a reverse correlation with the rpm decrease. In the case of the vertical forces close to the normal range, the probability of GT rotary file deformation were quite different depending on the rpm changes. In the case of greater vertical forces, the occurrences of deformation of the file were more frequent regardless of the rpm changes. 3. Deformation and breakage of file were also commonly observed in the expended time measurement experiments and GT rotary file deformation experiments in which low speed rpm (150rpm) was used and at the curved portion of the resin block.

• Restorative Dentistry and Endodontics
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• v.24 no.3
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• pp.503-510
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• 1999

The purpose of this study was to evaluate the amount of transportation of original canal, zip formation, permanent deformation and fracture of instruments after canal enlargement. In this study, the 60 resin blocks that have curved canals were randomly divided into 3 experimental groups with 20 teeth each according to instrument types and filling methods for canal enlargement. The curved canals of each experimental groups were enlarged to No 40 ISO size with the K-flexo stainless steel file (Group 1), Engine-driven Ni-Ti Profile new series(Group 2) and Engine-driven Ni-Ti Quantec 2000 series(Group 3) according to the manufacturer's recommendation. Pre- and postoperative X-rays were taken at same position and the films were scanned and the canal images were traced to determine the canal curvature according to the method of Schneider. The amount of reduction in canal curvature were calculated between pre- and postoperative X-rays. In addition to zip formation, permanent deformation and fracture of instruments were examined after canal enlargement. The results were as follows : 1. All experimental groups showed some loss of canal curvature after instrumentation. There was a significant change in curvature between before and after instrumentation in each group(p<0.001). 2. Engine-driven Ni-Ti instrumentations resulted in an average loss of curvature of 2.36 degrees for Profile new series, 3.43 degrees for Quantec series, and hand instrumentation showed an average loss of curvature of 6.48 degrees for K-flexo file. There was a statistical significant difference between hand instrumentation and engine-driven Ni-Ti instrumentations(p<0.05). But there was no statistical difference between Profile new series and Quantec series. 3. There were many apical zip formations in group 1(Hand instrumentation). But there were no apical zip formations in group 2,3(Engine-driven Ni-Ti instrumentation). 4. The instrument deformation occured 9 cases in group 1(K-flexo file), 2 cases in group 2(Profile new series) and 3 cases in group 3(Quantec) after instrumentation. And the instrument fracture occured 1 case in each group. The results showed that the engine-driven Ni-Ti instruments, if we use carefully according to manufacturer's recommendations, can be use effectively for instrumenting the curved root canals in case of the MAF was over size 40.

• Journal of Life Science
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• v.19 no.8
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• pp.1112-1118
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• 2009

In the present study, the effects of muddy water were compared and examined on the fish inhabiting Imha reservoir, E. erythropterus, H. labeo and Z. platypus in Cypriniformes, S. asotus in Siluriformes and S. scherzeri in Perciformes. In the gills of fish in muddy water, the secondary lamellae of fish in Cypriniformes showed more irregular gaps and more winding than those in Siluriformes and Perciformes. Also, the edema and detachment of epithelial cells was more detected in the gills in Cypriniformes, but clubbing was frequently detected in Perciformes and Siluriformes. Also, we found that muddy debris and minute particles attached to lamellae were frequently detected in Perciformes and Cypriniformes. The glomerulus in the kidney was much more constricted in Z. platypus in Cypriniformes. As a result, it is proposed that fish in Cypriniformes are more affected by muddy water. In the changes of blood components, which might be affected by muddy water, the concentrations of TP, ALB, TG, CHOL and A/G ratio, were high in Cypriniformes, and inorganic matters were abundant in Siluriformes. In addition, AST activity was relatively higher than ALT and both activities were higher in Cypriniformes than in Siluriformes. Taken together, the change in blood plasma may be caused by the reduction in voracity in the wake of muddy water, which results in tissue damage.