• Journal of Ecology and Environment
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• v.39 no.1
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• pp.71-80
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• 2016

The main goal of this study is to develop a multi-metric fishway assessment model (M_m-FA) and evaluate the efficiency of fishway. The M_m-FA model has three major fishway components with nine metrics: structural characteristics, hydraulic/hydrologic features, and biological attributes. The model was developed for diagnosing and assessing fishway efficiency and tested to Juksan Weir at the Yeongsan River Watershed. Structural characteristics of fishway included slope of the fishway (M₁), ratios of fishway width to stream width (M₂), and the proportion of orifice clogging and orifice size (M₃). Hydraulic/hydrologic characteristics included depth of fishway entrance head (M₄), depth of exit tail (M₅), and current velocity of inner fishway (M₆). Biological characteristics included fish species ratio of inner fishway to upper-lower weir (M₇), fish length distribution (M₈), and the proportion of migratory fish species to the total number of species (M₉). Overall, the assessment of fishway efficiency showed the total score of the M_m-FA model was 25 in the Juksan Weir, indicating "good condition" by the criteria of the five-level classification system. The M_m-FA model may be used as a key tool for the assessment of fishway efficiency, especially on the 16 weirs constructed for the "Four Rivers Restoration Project" after a partial calibration of M_m-FA model.

• Journal of Periodontal and Implant Science
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• v.31 no.1
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• pp.135-148
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• 2001

Gingival fibroblasts are major cellular component of gingiva. However, the molecular mechanisms of senescence of human gingival fibroblasts are unknown. Human fibroblasts undergo replicative senescence in vitro after a limited number of population doublings. A reduced rate of proliferation is a prominent phenomenon observed in senescent fibroblasts. This phenomenon is controled by cell cycle regulatory proteins. The purpose of present study was to investigate the effect of replicative senescence on cell cycle progression and to find out its molecular mechanisms in human gingival fibroblasts. Replicative senescence of gingival fibroblasts were induced by subsequent cultures that were repeated up to 18 passage. In the present study, I examined change of cell proliferation, cell activity, cell viability and cell cycle progression during the replicative process. Also, I examined expression of cell cycle regulatory proteins which was estimated by western blot analysis. Cell proliferation, cell activity and cell viability of gingival fibroblasts were notably decreased with increase of population doubling level(PDL). S phase was decreased and G1 phase was increased with increase of PDL. Western blot analysis showed that levels of P16, p21 and p53 of senescent gingival fibroblasts(PDL41, PDL58) were higher than young fibroblasts(PDL27) and cdk4 were lower than young fibroblasts(PDL27). In conclusion, these results suggest that proliferative function of human gingival fibroblasts may be decreased by replicative senescence and its molecular mechanisms may be activatied with p16, p21, p53 and pRB, and repressed wtih cdk4.

• Transactions of the Korean hydrogen and new energy society
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• v.29 no.4
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• pp.401-409
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• 2018

A numerical investigation has been conducted to find the effects of pressure losses by struts and rakes, and averaging methods on the performance of a multi-stage axial fan and a multi-stage axial compressor. Struts and rakes which produce pressure losses are installed upstream of the aerodynamic inlet plane in the fan and the compressor rigs. Some of normal stator vanes are substituted with thick vanes with total pressure probes to measure total pressure between stages. Three-dimensional Reynolds-averaged Navier- Stokes equations with $k-{\omega}$ SST turbulence model were applied to analyze the pressure losses by the struts, inlet rakes, and thick instrumented vanes. The hexahedral grids were used to construct computational domain. Inlet pressure losses were evaluated for the compressor as a function of Mach number. The passage pressure losses due to the instrumented vanes were evaluated at the two speed lines in the fan. Total properties, such as pressure and temperature, were evaluated at the exit of the fan and the compressor with two different averaging methods which are area-averaging and mass-averaging, respectively.

• Journal of Periodontal and Implant Science
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• v.25 no.2
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• pp.181-191
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• 1995

The ability of fibroblasts attach to teeth is of paramount imporance in re-establishing the lost connective tissue attachment after periodontal therapy. Tobacco contains a complex mixture of substances including nicotine. various nitrousamines, trace elements. and a variety of poorly characterized substances. The effects of nicotine on fibroblasts have reported an altered morphology and attachment of fibroblasts to substrates and disturbances in protein synthesis and secretion. This study examined the effect of nicotine, a major component of the particulate phase of tobacco smoke, on human gingival fibroblasts and periodontal ligament cells attachment to tissue culture surfaces and cellular activity of human gingival fibroblasts and periodontal ligament cells. Pooled human gingival fibroblasts made from extraction of 3rd molar were utilized between passage 4 and 5 and plated in 96 well plate at 20,000 cells per well. Cell number were determined using 3-(4,5-dimethylthiazole-2-y)2,5-diphenyltetrazolium bromide(MTI) , which is reflection of mitochondrial dehydrogenase activity. The concentration of nicotine used were 0.025, 0.05, 0.1, 0.2 and $0.4{\mu}M$, the average serum concentration for a smoker being approximately $0.1{\mu}M$. The results were as follows : 1. Attachment effects of nicotine on human gingival fibroblasts and periodontal ligament cells Excepts of $0.4{\mu}M$, the effects on attachment with increasing numbers of cells attaching with increasing nicotine concentrations, compared to control group. But over the 60min, return to control value. 2. The effect of cellular activity on human gingival fibroblasts and periodontal ligament cells. The cellular activity of human gingival fibroblasts and periodontal ligament cells were similar or decrease to control value at 1st incubation day. At 2nd incubation day, 0.05, 0.1, 0.2, $0.4{\mu}M$ concentrations were statistically different from control value on gingival fibroblasts group. But at 3rd incubation day, cellular activities of all experimental group were significantly decrease than control group.

• Journal of Bio-Environment Control
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• v.12 no.2
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• pp.101-105
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• 2003

This experiment was conducted to find out the effect of day length on the production of high quality plug seedlings in onion (Allium cepa L.). Two cultivars, ‘Changnyongdaego’ and‘Wolryun’, were grown to seedlings in 200-cell plug trays under 11.5, 12.5, 13.5 hours and natural day length. These seedlings were transplanted to the pot (16 cm In diameter) and grown under 16 hours day length. Number of leaves and neck diameter showed better growth in the longer than shorter day length treatments, but plant height old sheath length were retarded in the longer day length treatments. Growth such as no. of leaves, neck diameter, plant height and sheath length increased with the passage of day, but plant height and neck diameter decreased by treatment over 20 days with 13.5 hours day length. Bulbing and bulb size of onion after transplanting were enhanced in the seedlings cultured under longer day lengths. From the above results, treatment of long day length during seedling culture in plug tray can control the overgrowth and produce high quality plug seedlings.

• Journal of the Korean Arthroscopy Society
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• v.15 no.2
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• pp.125-131
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• 2011

Optimal treatment of the torn posterior cruciate ligament (PCL) remains controversial. The type of tibial fixation (transtibial vs inlay), the femoral tunnel position within the femoral footprint (central, eccentric or isometric), and the number of bundles in the reconstruction (single-bundle vs double-bundle) are controversial issues. The PCL has a better chance of spontaneously healing than the anterior cruciate ligament (ACL) because of a rich blood supply (near the branch of the middle genicular artery) and coverage with a thicker synovium. In general, for easier passage of the graft and full visualization of the original ligament attachment site during the precise positioning of the tunnel, the remaining PCL fibers are usually debrided during reconstruction. However, the remaining remnant structures would significantly contribute to the posterior stability of the knee joint, the healing of the graft, preserving proprioceptive function of the mechanoreceptors in the PCL. Double bundle PCL reconstruction may result in some surgical complications because of increased complexity of making tunnel. Therefore, single bundle PCL reconstruction with remnant preservation seems to be an effective procedure.

• Journal of Fisheries and Marine Sciences Education
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• v.18 no.2
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• pp.137-149
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• 2006

The typhoon, heavy rain, blizzard, storm and heavy snowfall had the main caused of natural disasters occurred in Korea from 1993 to 2002. Among them, typhoon has responsible for biggest disaster, recording about 47.4% of total economic damage. Typhoons concentrated mostly in the months from June to October. The average occurrence number in those months ranged from 3.9 to 5.5 based on 30 years of record(1971-2000). However, the numbers increased from 4.0 to 6.2 during the most recent 10 years(1991-2000). Jeju province, among others in Korea, was most frequently affected by typhoon which occurred 23 times during the period of 1991-2000. Typhoons which occurred from July to early August have passed mostly through the west of Jeju, whereas, those of late August to September have passed through the center and eastern sea area of Jeju. The typhoons 'Ramasun' and 'Rusa' caused severe damage in Jeju area in September 2003 and the surge heights were +39cm and +77cm, respectively. The main cause of the damage was surge height which was highly associated with the tidal phase at the time of typhoon passage. The damage caused by typhoon on the aquaculture, fishing boat and harbor cosatline wall around Jeju Island which was amounted to be 417 billion won(\) during the recent 3 years(2002-2004)

• Advances in environmental research
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• v.8 no.1
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• pp.71-84
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• 2019

Effective waterproofing of structures was a compulsory constraint to avoid leaks and dampness or humidity in walls, ceilings, roofs underground tank and underground room. Traditionally used methods of roof waterproofing were bitumen with tinny seared clay tiles are very troublesome, overwhelming time and involving high labor cost. These waterproofing methods are not allocation the purpose due to their intrinsic disadvantages. Prepackaged polymer modified slurries (PPPMS) are now attainment the vogue and easy to use, easily available in the market, cheaper in cost and more workable than the traditional methods of waterproofing. An experimental study has shown that prepackaged polymer modified slurries (PPPMS) are superior in cost and performance to as a roof water proof coatings. Bituminous coatings were mixed with water and different combination of prepackaged polymer modified slurries and primer respectively, to find optimum coverage underneath worst atmospheric conditions. Every specimen of different proportioned was applied on plane roofs and through the passage of time, their performance was checked, assessed and associated with each other. The roof of approximately 40000 ft² area of prepackaged polymer modified slurries was used will give us hundred percent result (no water seepage or no water absorption) therefore no complaints as compare to roofs area of approximately 24000 ft² bituminous coating was used for waterproofing they have shown the result of 30 to 40 percent water seepage. This result shows that prepackaged polymer modified slurries were two times cheaper than bituminous coating. Comparing an equal number of surfaces coated with a polymer modified prepackaged mortar and bitumen the prepackaged polymer modified slurries (PPPMS) showed excellent performance, ease of application and low bitumen coating cost.

• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.6
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• pp.93-101
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• 2012

Bridge deck has a role in a comfortable and safe passage of vehicles. At the same time, it preserves upper structure against the abrasion and shearing due to impact of traffic loads in bridges or has a role to protect the plate from off adverse effect of climatic process as rain, chemicals. Currently, the total number of inspected bridges is 6,248 in the general national road and to maintain effectively, Introduction of GPR system mounted in the vehicle has been considered. In this research, the comparison and analysis of bridge deck condition on general national road has been performed with major variations of superstructure type, span lengths, located region and ages by using 'the current status of road bridge and tunnel' that is provided by MLTM(Ministry of Land, Transport and Maritime Affairs). As a result, Condition assessment grade, superstructure type, age and length were derived as a major factor to determine priority for the condition assessment.

• Journal of Korean Society of Water and Wastewater
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• v.29 no.1
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• pp.77-88
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• 2015

Soil column experiments were evaluated effects of silver nanoparticles (i.e., 0, 2.5, 5, and 10 mg/L) on the microbial viability which is strongly associated with the degradation of organic matter, pharmaceutically active compounds(PhACs) and biological oxidation of nitrogenous compounds during river bank filtration. The addition of silver nanoparticles resulted in almost no change in the aqueous matrix. However, the intact cell concentration decreased with addition of silver nanoparticles from 2.5 to 10 mg/L, which accounted for 76% to 82% reduction compared to that of control (silver nanoparticles free surface water). The decrease in adenosine triphosphate was more pronounced; thus, the number and active cells in aqueous phase were concurrently decreased with added silver nanoparticles. Based on the florescence excitation-emission matrix and liquid chromatograph - organic carbon detection analyses, it shows that the removal of protein-like substances was relatively higher than that of humic-like substances, and polysaccharide was substantially reduced. But the extent of those substances removed during soil passage was decreased with the increasing concentration of silver nanoparticles. The attenuation of ionic PhACs ranged from 55% to 80%, depending on the concentration of silver nanoparticles. The attenuation of neutral PhACs ranged between 72% and 77%, which was relatively lower than that observed for the ionic PhACs. The microbial viability was affected by silver nanoparticles, which also resulted in inhibition of nitrifiers.