• The korean journal of orthodontics
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• v.50 no.1
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• pp.63-71
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• 2020

Odontogenic keratocysts (OKCs) are one of the most aggressive cysts in the oral and maxillofacial area because of their high recurrence rate and infiltrative behavior. In growing patients with OKCs, a radical treatment approach might cause numerous complications, including the disturbance of jaw growth and loss of the involved tooth. This case report describes successful comprehensive orthodontic treatment combined with marsupialization of the cyst in a young girl who exhibited an OKC with impacted teeth. The 10-year-old girl presented with an OKC extending from the mandibular symphysis through the left mandibular body, with ectopic impaction of the mandibular left canine and first premolar, as well as congenitally missing bilateral mandibular second premolars. Interestingly, spontaneous improvement of the positions of the ectopic impacted teeth, along with a reduction in the size of the cyst, occurred during marsupialization. The sequential use of removable and fixed appliances enabled orthodontic traction of the impacted teeth. The treatment outcome was stable at 2.5 years after the end of the treatment. We speculate that comprehensive orthodontic treatment combined with marsupialization can be an effective treatment strategy for patients with OKCs, especially when they are encountered in young, growing patients with impacted teeth.

• Journal of the Korean Institute of Landscape Architecture
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• v.24 no.4
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• pp.123-131
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• 1997

Since the industrial revolution. the growth of cities has been especially apid and the rate of ulbanization has been high. This urban development is encroaching on the natural environment because the cities are developed with not only residential estates, industrial area and buildings but also with infrastructure. The surface area of the city is sealed ,with pavement whereas nature is disturbed and modified. The hydrological cycle in the city is inf1uenced by the change of land use I. e., from forest to agricultural land, talc draining of wetlands and above all the increase of built-up areas. The surface retention and interception of precipitation in the city is reduced. because the surface area is now smooth and solid. The characteristics of the hydrological cycle in the city are increased runoff, reduced evapotranspiration and infiltraction . We have too much faith in technology although it may cause more unforseen problems. We build more river banks and 'emulation dams and straighten rivers and streams in order to protect ourselves from disasters.. However. the results of hose developments are often higher$.$ water levels, the disturbance of aquatic ecosystems and the reduction of biodiversity. Therefore, we should examine problems from the hydrological cycle in cities and study a natural system as close cities to nature as possible. This paper shows the problems caused by the hydrological cycle in the city. The ecology-oriented method and design must be used in order to protect our environment from dicturbance.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.6
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• pp.23-29
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• 2003

Transonic two-phase flow of Saturated humid air, in which relative humidity is 100%, with various condensation processes around thin airfoils is investigated. The study uses an extended transonic small-disturbance(TSD) model of Rusak and Lee [11, 12] which includes effects of heat addition to the flow due to condensation. Two possible limit types of condensation processes are considered. In the nonequilibrium and homogeneous process, the condensate mass fraction is calculated according to classical nucleation and droplet growth rate models. In the equilibrium process, the condensate mass fraction is calculated by assuming an isentropic process. The flow and condensation equations are solved numerical1y by iterative computations. Results under same upstream conditions describe the flow structure, field of condensate, and pressure distribution on airfoil's surfaces. It is found that flow characteristics, such as position and strength of shock waves and airfoil’s pressure distribution, are different for the two condensation processes. Yet, in each case, heat addition as a result of condensation causes significant changes in flow behavior and affects the aerodynamic performance of airfoils.

• The Korean Journal of Ecology
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• v.15 no.2
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• pp.103-115
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• 1992

This dissertation, which has been prepared in the region of cheju(33o31'N, 126o32'E) from may,1987 to appril, 1989, is to elucidate the dominant characteristics of early stages in secondary succession, by examining the life history of erigeron annuus for the seeding depth of a seed was dependent upon the degree of shading. That is, on the area of ocm,the more tense the shading was, the more germination percentage was increased, while, in the case of 1.5cm, it was somewhat increased, when shading bwcame ess and less tense. The rosette of e. annuus, through its relative light intensity was decreased by shading, up to 5% of natural light, showed some strong shade tolerance, which had no difficulty in matter production. The species diversity of mixed-species community was the highest in the middle of April, the lowest in the last of may. The dominance index was the highest in the late may, the lowest in the middle of April. Toward the end of may, the occupation rate of dominance species was the highest. There was a neutral relationship between intraspecific and interspecific, owing to the differentiation of its niche, temporally and spatially. Productive structure of the community revealed a narrow leaf type which was concentratively distributed in the mid part of community height. The relative light intensity of community ground surface was 6.1%, the leaf inclination 60o,the extinction coefficient(k) 0.4, biomass of community 1,045.6 g.d.w./m2,T/Rratio 9.3, C/Frate 7.0 and sumgermanition, shade toarance and community characteristics on erigeron annuus l.in chejumed leaf area index 3.88. through the various life cycles o e.annuus, we can say that it decreases mortality of seeding caused by some stress and disturbance, for germination lasts for a long time at any opportunity available, and it promotes population growth. The strong shade tolerance of a rosette and the variableness of a life from differentiate the niche between intraspecific and interspecific within the community, and avoid the direct competition between them, thus poromoting community growth.

• Korean Business Review
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• v.16
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• pp.77-97
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• 2003

The Korean government issues the policy that regional government mat change the regional tax rates for economic growth. On the ground that change in regional tax rate incurs the disturbance in regional economy and entails tax competition, regional government does not accept the proposal. The CGE simulation result shows that tax competition reveals the trade-off relation between efficiency, balanced national development, and equity. Thereby, the stance of regional government can be justified by the results. Therefore central government has to grope for some reconcile means that efficiency and equity can be harmonized. The proposal can be justified by the analyses.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.7
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• pp.3213-3222
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• 2016

Background: Methyl donor status influences DNA stability and DNA methylation although little is known about effects on DNA methyltransferases. The aim of this study was to determine whether methyl-donor status influences DNA methyltransferase (Dnmt) gene expression in cervical cancer cells, and if so, whether there are associated effects on global DNA methylation. Materials and Methods: The human cervical cancer cell line, C4-II, was grown in complete medium and medium depleted of folate (F-M+) and folate and methionine (F-M-). Growth rate, intracellular folate, intracellular methionine and homocysteine in the extracellular medium were measured to validate the cancer cell model of methyl donor depletion. Dnmt expression was measured by qRT-PCR using relative quantification and global DNA methylation was measured using a flow cytometric method. Results: Intracellular folate and methionine concentrations were significantly reduced after growth in depleted media. Growth rate was also reduced in response to methyl donor depletion. Extracellular homocysteine was raised compared with controls, indicating disturbance to the methyl cycle. Combined folate and methionine depletion led to a significant down-regulation of Dnmt3a and Dnmt3b; this was associated with an 18% reduction in global DNA methylation compared with controls. Effects of folate and methionine depletion on Dnmt3a and 3b expression were reversed by transferring depleted cells to complete medium. Conclusions: Methyl donor status can evidently influence expression of Dnmts in cervical cancer cells, which is associated with DNA global hypomethylation. Effects on Dnmt expression are reversible, suggesting reversible modulating effects of dietary methyl donor intake on gene expression, which may be relevant for cancer progression.

• Ecology and Resilient Infrastructure
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• v.9 no.3
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• pp.183-193
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• 2022

The growth inhibitory effect of Microcystis aeruginosa according to the ultrasonic irradiation time was evaluated using a large algae sample volume (10 L) for various ultrasonic irradiation times (0.5, 1, 1.5, 2, 2.5 and 3 hr) at a laboratory scale. Based on the analysis of Chl-a and cell number of M. aerginosa, algae growth inhibition was observed with the decrease in Chl-a and cell number in all experimental groups after the ultrasonic irradiation. For the experimental group (T_B, T_C, T_D) with an ultrasonic irradiation time of less than 2 hours, rapid regrowth of algae was observed after growth inhibition, but the experimental group (T_E, T_F, T_G) with an irradiation time of more than 2 hours successfully inhibited algal growth lasting one or two more days. Based on the comparison of the recovery time to initial cell number the experimental group (T_B, T_C, T_D) took less than 20 days whereas the experimental group (T_E, T_F, T_G) took about 30 days. Correspondingly, the experimental group showed a high first order decay rate (𝜅) in proportion to the ultrasonic irradiation time during the growth inhibition period. Additionally, the specific growth rates (𝜇) during regrowth in the experimental group with irradiation time of more than 2 hours were relatively low compared to those in the experimental group with less than 2 hours. Therefore, ultrasonic irradiation for more than 2 hours is required for long-term (30 days) inhibition of algal growth in stagnant waters. However, the appropriate ultrasonic irradiation time for algae growth inhibition should be determined according to various field conditions such as the volume of stagnant water, water depth, flow rate, algae concentration, etc. Finally, damages to the algal cell surface and cell membrane were clearly observed, and both destruction and disturbance of gas vesicles of M. aeruginosa in the experimental group were discovered, indicating the growth inhibitory effect of Microcystis aeruginosa according to the ultrasonic irradiation time was confirmed.

• Journal of Broadcast Engineering
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• v.8 no.4
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• pp.437-451
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• 2003

With the rapid growth of internet technologies and wide availability of multimedia computing facilities, the enforcement of multimedia copyright protection becomes an important issue. Digital watermarking is viewed as an effective way to deter content users from illegal distributions. In recent years, digital watermarking has been intensively studied to achieve this goal. However, when the watermarked media is transmitted over the channels modeled as the additive white Gaussian noise (AWGN) channel, the watermark information is often interfered by the channel noise and produces a large number of errors. So many error-correcting codes have been applied in the digital watermarking system to protect the embedded message from the disturbance of the noise, such as BCH codes, Reef-Solomon (RS) codes and Turbo codes. Recently, low-density parity-check (LDPC) codes were demonstrated as good error correcting codes achieving near Shannon limit performance and outperforming turbo codes nth low decoding complexity. In this paper, in order to mitigate the channel conditions and improve the quality of watermark, we proposed the application of LDPC codes on implementing a fairly robust digital image watermarking system. The implemented watermarking system operates in the spectrum domain where a subset of the discrete wavelet transform (DWT) coefficients is modified by the watermark without using original image during watermark extraction. The quality of watermark is evaluated by taking Into account the trade-off between the chip-rate and the rate of LDPC codes. Many simulation results are presented in this paper, these results indicate that the quality of the watermark is improved greatly and the proposed system based on LDPC codes is very robust to attacks.

• International Journal of Fluid Machinery and Systems
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• v.2 no.4
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• pp.439-448
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• 2009

Three inducers were designed to avoid cavitation instabilities. This was accomplished by avoiding the interaction of tip cavity with the leading edge of the next blade. The first one was designed with extremely larger leading edge sweep, the second and third ones were designed with smaller incidence angle by reducing the inlet blade angle or increasing the design flow rate, respectively. The inducer with larger design flow rate has larger outlet blade angle to obtain sufficient pressure rise. The inducer with larger sweep could suppress the cavitation instabilities in higher flow rates more than 95% of design flow coefficient, owing to weaker tip leakage vortex cavity with stronger disturbance by backflow vortices. The inducer with larger outlet blade angle could avoid the cavitation instabilities at higher flow rates, owing to the extension of the tip cavity along the suction surface of the blade. The inducer with smaller inlet blade angle could avoid the cavitation instabilities at higher flow rates, owing to the occurrence of the cavity first in the blade passage and its extension upstream. The cavity shape and suction performance were reasonably simulated by three dimensional CFD computations under the steady cavitating condition, except for the backflow vortex cavity. The difference in the growth of cavity for each inducer is explained from the difference of the pressure distribution on the suction side of the blades.

• Korean Journal of Environmental Agriculture
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• v.28 no.3
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• pp.243-248
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• 2009

Chinese cabbage cultivation has been typically practiced in alpine sloped farmland in Gangwon province, and caused severe soil erosion by soil disturbance like tillage. Cultivation of wild edible greens such as Aster scaber Thunb. and Ligularia fischeri Turcz. could be one of alternative ways to reduce soil erosion, because their residues become stubble mulch after harvest, and there is no need for tillage every year. Therefore, the objective of this research was to estimate the effect of nitrogen application rates for the maximum production of Aster scaber Thunb. and Ligularia fischeri Turcz. in the early cultivation stages. Total N contents of Aster scaber Thunb. and Ligularia fischeri Turcz. increased with the increment of fertilizer application rates. Maximum growth of Aster scaber Thunb. and Ligularia fischeri Turcz. was observed with the highest rates of fertilizer. We obtained the relationship between Aster scaber Thunb. and N application rate, as y = $-0.296x^2$ + 73.82x + 5246 (R = 0.998). There was no significant difference for Aster scaber Thunb production between N application rates for 120 and 160 kg/ha. Also, the relationship between Ligularia fischeri Turcz. and N application rate was y = $-0.135x^2$ + 32.86x + 1529 ($R^2$ = 0.965) in the first year trial after transplanting.