• Investigative Magnetic Resonance Imaging
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• v.17 no.4
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• pp.275-285
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• 2013

Purpose : The objective of this study was to investigate effects of different smoothing kernel sizes on brain tissue-masked susceptibility-weighted images (SWI) obtained from normal elderly subjects using voxel-based analyses. Materials and Methods: Twenty healthy human volunteers (mean $age{\pm}SD$ = $67.8{\pm}6.09$ years, 14 females and 6 males) were studied after informed consent. A fully first-order flow-compensated three-dimensional (3D) gradient-echo sequence ran to obtain axial magnitude and phase images to generate SWI data. In addition, sagittal 3D T1-weighted images were acquired with the magnetization-prepared rapid acquisition of gradient-echo sequence for brain tissue segmentation and imaging registration. Both paramagnetically (PSWI) and diamagnetically (NSWI) phase-masked SWI data were obtained with masking out non-brain tissues. Finally, both tissue-masked PSWI and NSWI data were smoothed using different smoothing kernel sizes that were isotropic 0, 2, 4, and 8 mm Gaussian kernels. The voxel-based comparisons were performed using a paired t-test between PSWI and NSWI for each smoothing kernel size. Results: The significance of comparisons increased with increasing smoothing kernel sizes. Signals from NSWI were greater than those from PSWI. The smoothing kernel size of four was optimal to use voxel-based comparisons. The bilaterally different areas were found on multiple brain regions. Conclusion: The paramagnetic (positive) phase mask led to reduce signals from high susceptibility areas. To minimize partial volume effects and contributions of large vessels, the voxel-based analysis on SWI with masked non-brain components should be utilized.

• Journal of Science Education
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• v.38 no.3
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• pp.718-736
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• 2014

This study was intended to determine PCK of the middle school science teachers on Mendelian genetics and factors influenced to form their PCKs. Two science teachers with biology major with a teaching experience over 5 years were chosen as the subject. Data were collected by class observation, semi-structured interview, teacher questionnaire survey, Content Representation and Pedagogical and Professional-experience Repertoire. The collected data were analyzed based on Magnusson's PCK for science teaching consisting of five components: (a) the orientation toward teaching science, (b) the knowledge of science curriculum, (c) the knowledge of students' understanding, (d) the knowledge of assessment, and (e) the knowledge and belief in the instructional strategies to teach science. Teachers could have the orientation toward teaching science served as an assisting role to support students' abilities. Both subject teachers seemed to focus on giving lectures. Their efforts to improve students' exploration methods and abilities were not expressed enough in their real classes and they found that students struggled to understand Mendelian genetics. Therefore, they should have explained them in an easier way and worked harder to make their students understood accurately and applied basic and advanced concepts of Mendelian genetics. They found students' preconception and misconception regarding Mendelian genetics and wished to enhance their learning effects by various teaching strategies such as correcting misconception, adding the history of science and simply assessing students' affirmative domains. It was also found that factors influenced to form PCK regarding Mendelian genetics by both teachers were as follows: teacher's personality and endeavor, textbooks and guidance books, schools and their circumstances, teaching experience, experience as a learner, interaction with their colleagues, and university curriculum. Both teachers said that it was important for teachers to make every efforts to give better classes.

• Korean Journal of Ecology and Environment
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• v.39 no.4 s.118
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• pp.462-470
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• 2006

The zooplankton community dynamics and grazing experiments was evaluated along a 40 km section of the lower Seomjin river system. Zooplankton was sampled twice a month from January 2005 to June 2006 at three sites (River mouth; RKO, Seomjin bridge: RK12 and Gurae bridge: RK36) in the main river channel. During the study period, the values of most limnological parameters in the three sites were fairly similar, except for conductivity. Annual variation of conductivity in River mouth and Seomjin bridge was more dramatic than which of the other site. There were statistically significant spatial and seasonal differences in zooplankton abundance (ANOVA, P<0.01). Total abundance of major zooplankton groups at both stations was much higher than in Gurae bridge. Among the macrozooplankton, cladocerans abundance was negligible in study sites during study periods. Community filtering rates (CFRs) for phytoplankton and bacteria varied from 0 to 50 mL $L^{-1}\;D^{-1}$ and from 0 to 45 mL $L^{-1}\;D^{-1}$, respectively. The spatial variation of CFRs for phytoplankton was significant (ANOVA, P<0.05). The CFRs of copepods for phytoplankton and bacteria was much higher than that of cladocerans at study sites. Total zooplankton filtering rates on bacteria were slightly lower than filtering rates on phytoplankton. The CFRs of microzooplankton (MICZ) for bacteria were much higher than for macrozooplankton (MACZ) at all sites. Considering the total zooplankton community, MICZ generally were more important than MACZ as grazers of bacteria and phytoplankton in freshwater zone, while MACZ were more important than MICZ as grazers of phytoplankton in brackish zone.

• Korean Journal of Environmental Agriculture
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• v.20 no.3
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• pp.155-161
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• 2001

This study was carried out to investigate cytotoxicity of paraquat or bentazone on NIH 3T3 fibroblasts, toxicity of paraquat or bentazone, and compensatory effects of 3-Methylcholanthrene(3-MC) on the rat liver. In order to MTT assay, the $5.0{\times}10^4$ cell/mL of NIH 3T3 fibroblast in each well of 24 multidish were cultured. After 24 hours, the cells were treated with solution of paraquat or bentazone(1, 25, 50, 100 ${\mu}M$ respectively). After the NIH 3T3 fibroblast of all groups were cultured in same condition for 48 hours. MTT assay were performed to evaluate the cytotoxicity of cell organelles. Paraquat or bentazone $MTT_{50}$ were 1668.97 ${\mu}M$ and 1506.97 ${\mu}M$, respectively. These $IC_{50}$ of paraquat or bentazone were decided low cytotoxicity by Borenfreund. In order to observe the toxicity and compensatory effects of paraquat or bentazone on the rat liver, Sprague-Dawley male rats were used as experimental animals and divided into paraquat or bentazone only treated group and simultaneous application group of paraquat or bentazone and 3-MC. At 30 min and 1, 3, 6, 12, 24, 48 and 96 hrs interval after each treatment, the animals were sacrificed by decapitation and liver were immediately removed, immersed in fixatives, and processed with routine method for light microscopic study. Paraffin sections were stained with H-E, PAM and Best Carmine. Under the light microscope, degenerative changes of hepatic lobules were frequently observed in portal area from 3 hrs after paraquat or bentazone treatment. All hepatic cells were induced degenerative change at 12 hrs and more severe degenerative change at 48 hrs after paraquat or bentazone treatment. Especially, hepatic cells of bentazone only treated group were distinctly showed pyknotic. Glycogen granules were increased in portal area at 3 hrs, all hepatic cells at 12 hrs and remarkably increased at 48 hrs after paraquat or bentazone treated group. But hepatic cells of bentazone only treated group were regeneration at 48 hrs from portal area and glycogen granules of hepatic cells of paraquat or bentazone and 3-MC combination treated group showed in central area only at 48 hrs. The results indicate that 3-MC may be decrease paraquat or bentazone cytotoxicity on the rat liver.

• Journal of Bio-Environment Control
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• v.9 no.3
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• pp.171-178
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• 2000

Gross photosynthetic rats of leaves of hydroponically grown cucumber plants(Cucumis sativus L. cv. Guwoosalichungjang) were measured under various conditions of photosynthetic photon flux(PPF), ambient $CO_2$ concentration, air temperature and leaf nitrogen contents. Light compensation point of leaf photosynthesis appeared to be in the range of 10~20$\mu$mol.m$^{-2}$ .s$^{-1}$ and light saturation point be above 1000$\mu$mol.m$^{-2}$ .s$^{-1}$ . Gross photosynthetic rates increased persistently and asymptotically as air temperature rose from 12$^{\circ}C$ to 32$^{\circ}C$. However, there were only small differences in gross photosynthetic rates in the range of 24-32$^{\circ}C$, so that the range seemed to be optimal for photosynthesis of cucumber plants at the condition of $CO_2$ concentration of 400$\mu$mol.mol$^{-1}$ and PPF of around 400$\mu$mol.m$^{-2}$ .s$^{-1}$ . $CO_2$ compensation point of leaf photosynthesis appeared to be in the range of 20-40$\mu$mol.mol$^{-1}$ and $CO_2$ saturation point be above 1200$\mu$mol.mol$^{-1}$ . Gross photosynthetic rates increased sigmoidally as leaf nitrogen content increased. These environmental factors interacted synergistically to enhance gross photosynthetic rate, so that the rate increased multiplicatively s level of one factor increased progressively with higher levels of he other factors. Mathematical models wer developed to estimate the gross photosynthetic rate in accordance with the variations of these environmental factors. These modes can be used not only to explain he variation of growth or yield of cucumber plants under different environmental conditions but also as building blocks of plant growth model or expert system of cucumber plants.

• Korean Journal of Microbiology
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• v.38 no.3
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• pp.153-161
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• 2002

Sox4, a transcription factor, consists of three functional domains: an HMG-box domain as a DNA binding domain, serine rich region as a transactivation domain and glycine rich region (GRR), an unknown functional domain. Although Sox4 is known to be functionally involved in heart, B-cell and reproductive system development, its physiological function remains to be elucidated. We used pGEX expression system to develop a simple and rapid method for purifying Sox4 protein in suitable forms for biochemical studies of their functions. Unexpectedly, we observed that full-length Sox4 appears to be protease-sensitive during expression and purification in E. coli. To map the protease-sensitive site in Sox4, we generated various constructs with each of functional domains of Sox4 and purified as the GST-Sox4 fusion proteins using glutathione beads. We found that the specific cleavage site for the proteolytic enzyme, which exists in E. coli, is localized within the novel GRR of Sox4. Our study suggest that the GRR of Sox4 may a target for the cellular protease action and this cleavage in the GRR may be involved in regulating physiological function of Sox4. Additionally, our study may provide a useful method for investigating the proteolytic cleavage of the target molecule in E. coli.

• 한국산학경영학회:학술대회논문집
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• 2004.11a
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• pp.101-123
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• 2004

This study examines empirically the significant changes in tax payments when the consolidated tax return is introduced in the future. We estimate the consolidated tax payments under the eight cases which are classified as such : whether only 100% ownership subsidiaries should be included or 80% and over, whether all subsidiaries should be included or only subsidiaries with loss, and whether unrealized profits from intercompany transactions should be excluded or not. After estimating the consolidated tax payments, we test the difference between the consolidated tax payments and the sum of the individual tax payments of the subsidiaries. The results of the test show that the consolidated tax payments are significantly less than the sum of the individual tax payments of the subsidiaries. We interpret that the inclusion of the losses of the subsidiaries in the consolidated tax base makes the tax payment decrease. Based on our analysis about 3.8 billion Won per each parent company would decrease due to the introduction of the consolidated tax return. And we find that under the mandatory consolidated tax return system the significant difference between the consolidated and individual tax payment exists except that the only 100% ownership subsidiaries are included and unrealized profits from intercompany transactions are not excluded. However, when the parent companies have the discretion to select the consolidated subsidiaries, the consolidated tax payments are significantly less than the sum of the individual tax payments of the subsidiaries regardless of the ownership percentage, inclusion of the loss of the subsidiaries and exclusion of the unrealized profits.

• Korea journal of population studies
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• v.21 no.2
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• pp.182-227
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• 1998

Korean government decided to adopt an explicit population control policy in 1961 and from the following year the establishment and operation of the national family planning programme was included in each of the Five-Year Economic Development Plans that began in 1962. This policy was pursued in the understanding that without proper population control measures korea could not be able to achieve economic development. Korean national family planning programme is characterized by contraceptive target system through public health network with distribution of free contraceptives by family planning field workers and clinical contraceptive services such as IUD, vasectomy and tubaligation at designated clinics by the government. In addition, IE&C activities by the Planned Parenthood Federation of Korea and programme evaluation and research by the Korea Institute for Health and Social Affairs contributed to the development of the government programme. Between 1960 and mid 1980s the nation's total fertility rate was reduced from 6.0 to population replacement level of 2.1 and thereafter it has been maintained at 1.6 to 1.7 of below replacement level. With a short period of less than three decades fertility transition was completed in Korea. It is estimated that if the current level of below replacement fertility continues, the population in Korea stabilize at around 52.78 million people by the year 2028, and it will begin to decrease thereafter. Under this circumstances, the government adopted new directions and strategies of the population policy in June 1996, focused primarily on population quality and social welfare than on demographic arenas. In spite of over 80 percent of high contraceptive prevalence among married women, high incidence of induced abortions is maintained. Moreover, the prevalence of sex selective induced abortions using procedures to determine the sex of the fetus has resulted in an imbalance in the sex ratio at birth. In order to overcome those problems associated with reproductive health new policy for population quality control and health promotion programme should be highly strengthened in the future.

• Korean Journal of Remote Sensing
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• v.36 no.5_1
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• pp.847-860
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• 2020

The 2-pass DInSAR (Differential Interferometric SAR) processing steps for DEM generation consist of the co-registration of SAR image pair, interferogram generation, phase unwrapping, calculation of DEM errors, and geocoding, etc. It requires complicated steps, and the accuracy of data processing at each step affects the performance of the finally generated DEM. In this study, we developed an improved method for enhancing the performance of the DEM generation method based on the 2-pass DInSAR technique of TanDEM-X bistatic SAR images was developed. The developed DEM generation method is a method that can significantly reduce both the DEM error in the unwrapped phase image and that may occur during geocoding step. The performance analysis of the developed algorithm was performed by comparing the vertical accuracy (Root Mean Square Error, RMSE) between the existing method and the newly proposed method using the ground control point (GCP) generated from GPS survey. The vertical accuracy of the DInSAR-based DEM generated without correction for the unwrapped phase error and geocoding error is 39.617 m. However, the vertical accuracy of the DEM generated through the proposed method is 2.346 m. It was confirmed that the DEM accuracy was improved through the proposed correction method. Through the proposed 2-pass DInSAR-based DEM generation method, the SRTM DEM error observed by DInSAR was compensated for the SRTM 30 m DEM (vertical accuracy 5.567 m) used as a reference. Through this, it was possible to finally create a DEM with improved spatial resolution of about 5 times and vertical accuracy of about 2.4 times. In addition, the spatial resolution of the DEM generated through the proposed method was matched with the SRTM 30 m DEM and the TanDEM-X 90m DEM, and the vertical accuracy was compared. As a result, it was confirmed that the vertical accuracy was improved by about 1.7 and 1.6 times, respectively, and more accurate DEM generation was possible with the proposed method. If the method derived in this study is used to continuously update the DEM for regions with frequent morphological changes, it will be possible to update the DEM effectively in a short time at low cost.

• The Journal of Korean Academy of Prosthodontics
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• v.50 no.2
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• pp.92-98
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• 2012

Purpose: The aim of this study was to evaluate the effects of different abutment materials on abutment screw loosening and settling-down effect in conical connection type implant system. Materials and methods: Three types of abutment, cementation, gold UCLA, and metal UCLA abutment were used. Two UCLA groups were fabricated in a similar pattern to cementation abutment. Type III gold alloy and Nickel-Chromium alloy was used for casting gold UCLA abutment and metal UCLA abutment, respectively. Fixture and abutment were tightened to 30 Ncm by using digital torque controller and re-tightening was conducted with same force after 10 minutes. Digital torque gauge was used to measure loosening torque and fixture/abutment length was measured by digital micrometer. Dynamic loads between 25 N and 250 N were applied with $0^{\circ}$ angle to the abutment axis. After loading, fixture/abutment length was re-measured and amount of settlement was calculated. Loosening torque value was also measured for comparison Results: All three groups showed significant differences of length when comparing before and after loading, but there was no significant difference of settling amount in all groups. Loosening torque values were significantly decreased when comparing before and after loading in all groups($P$<.05). However, there was no significant difference in loss of loosening torque values when compared to groups. Conclusion: In internal conical connection type implants, dynamic load affected on settlement and loosening torque of implant, but there was no differences between abutments materials. Likewise gold UCLA abutment, metal UCLA abutment might be able to withstand functional load.