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OSMI를 이용한 달 촬영 가능 시각 결정을 위한 고속 시뮬레이터 개발

  • Kang, Chi-Ho
    • Aerospace Engineering and Technology
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    • v.1 no.2
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    • pp.132-140
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    • 2002
  • By utilizing OSMI (Ocean Scanning Multi-spectral Imager) onboard KOMPSAT-1, the moon can be imaged. Because the moon has no atmosphere and reflects sun lights at a constant rate, it can be the radiance source for calibration of OSMI. But there are a lot of risks which made KOMPSAT-1 enter into safe-hold mode. So planning the imaging of the moon with OSMI should be determined seriously with consideration to information on KOMPSAT-1 operation, the moon, the sun, etc. But it takes a long time for determining the imaging time of the moon using MCE(Mission Control Element) simulator and there are operational problems to be solved. In this paper, fast simulator for determining imaging time for the moon with OSMI has been developed. The proper timeline for imaging the moon and the position of the moon image in OSMI image coordinates and the phase of the moon are determined. STK was used for acquiring information on KOMPSAT-1, the moon, the sun and the characteristitcs of OSMI are considered. As a result, we can determine imaging time of the moon with OSMI much faster and efficiently.

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Endometrial histology and predictable clinical factors for endometrial disease in women with polycystic ovary syndrome

  • Park, Joon-Cheol;Lim, Su-Yeon;Jang, Tae-Kyu;Bae, Jin-Gon;Kim, Jong-In;Rhee, Jeong-Ho
    • Clinical and Experimental Reproductive Medicine
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    • v.38 no.1
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    • pp.42-46
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    • 2011
  • Objective: This study was aimed to investigate endometrial histology and to find predictable clinical factors for endometrial disease (hyperplasia or cancer) in women with polycystic ovary syndrome (PCOS). Methods: We investigated the endometrial histology and analyzed the relationship between endometrial histology and clinical parameters, such as LH, FSH, estradiol, testosterone, fasting and 2 hours postprandial glucose and insulin, insulin resistance, body mass index, endometrial thickness, menstrual status from 117 women with PCOS. Statistical analysis was performed with chi square and t-test, p-value<0.05 was considered as statistically significant. And receiver operating characteristic curve was used to find predictable clinical factors for endometrial disease and to decide the cuff off values. Results: In 117 women with PCOS, endometrial histologic profiles are as follows: proliferative phase in 90 women (76.9%), endometrial hyperplasia in 25 women (21.4%), and endometrial cancer in 2 women (1.7%). Of 25 women with endometrial hyperplasia, simple hyperplasia without atypia, complex hyperplasia without atypia and complex hyperplasia with atypia were diagnosed in 15 (12.8%), 6 (5.1%), 4 (3.4%) women, respectively. Age and endometrial thickness were significantly related with endometrial disease, p=0.013 and p=0.001, respectively. At the cut off level of 25.5 years in age, sensitivity and specificity predicting for endometrial disease were 70.4% and 55.6%, respectively (p=0.023). At the cut off level of 8.5 mm in endometrial thickness, sensitivity and specificity were 77.8% and 56.7%, respectively (p=0.000). Conclusion: In women with PCOS, the incidence of endometrial hyperplasia and cancer were 21.4% and 1.7%. The age and endometrial thickness may be used as clinical determining factors for endometrial biopsy.

Molecular Dynamics (MD) Study of Proton Exchange Membranes for Fuel Cells (연료전지용 수소이온 교환막의 분자동역학 연구)

  • Park, Chi Hoon;Nam, Sang Yong;Hong, Young Taik
    • Membrane Journal
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    • v.26 no.5
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    • pp.329-336
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    • 2016
  • Proton exchange membrane (PEM) is one of the key components of membrane-electrode assembly (MEA), which plays important role in fuel cell performance together with catalysts. It is widely accepted that water channel morphology inside PEMs as a proton pathway significantly affects the PEM performance. Molecular dynamics (MD) simulations are a very useful tool to understand molecular and atomic structures of materials, so that many related researches are currently being studied. In this paper, we summarize the current research trend in MD simulations, present which properties can be characterized, and finally introduce the usefulness of MD simulations to the researchers for proton exchange membranes.

Identification of a Domain in Yeast Chitin Synthase 3 Required for Biogenesis of Chitin Ring, But Not Cellular Chitin Synthesis

  • Park Hyun-Sook;Park Mee-Hyun;Kim Chi-Hwa;Woo Jeeun;Lee Jee-Yeon;Kim Sung-Uk;Choi Wonja
    • Proceedings of the Microbiological Society of Korea Conference
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    • 2000.10a
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    • pp.39-45
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    • 2000
  • It hab been proposed that CHS3-mediated chitin synthesis during the vegitative cell cycle is regulated by CHS4. To investigate direct protein-protein interaction between their coding products, we used yeast two hybrid system and found that a domain of Chs3p was responsible for interaction with Chs4p. This domain, termed MIRC3-4 (maximum interacting region of chs3p with chs4p), spans from 647 to 700 residues. It is well conserved among CHS3 homologs of various fungi such as Candida albicans, Emericella nidulans, Neurospora crassa, Magnaporthe grisea, Ustilago maydis, Glomus versiforme, Exophiala dermatitidis, Rhizopus microsporus. A series of mutaion in the MIRC3-4 resulted in no appearance of chitin ring at the early G 1 phase but did not affect chitin synthesis in the cell wall after cytokinesis. Absence of chitin ring could be caused either by delocalization of Chs3p to the septum or by improper interaction with Chs4p. To discriminate those two, not mutually exclusive, alternatives, mutants cells were immunostained with Chs3p-specific antibody. Some exhibited localization of chs3p to the septum, while others failed. These results indicate that simultaneous localization and activation Chs3p by Chs4p is required for chitin ring synthesis.

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A Conceptual Model of Web-based VE Cost Model Analysis System (웹 기반 VE Cost모델 분석 시스템의 개념적 모형)

  • Lee, Chang-Hong;Oh, Chi-Don;Park, Chan-Sik
    • Proceedings of the Korean Institute Of Construction Engineering and Management
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    • 2007.11a
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    • pp.416-419
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    • 2007
  • In the case of domestic, related information of expenses in order to draw up cost model at the early stage haven't been stored systematically; moreover, similar projects which were accomplished in the past time have lacked data about actual results connected itself. Accordingly, a reliable object hasn't been selected because validity of cost comparing a main function is difficult to dearly decide. Consequently, This study Cost model who can procures and shares and utilizes, studies that is achieved past Cost information of similarity project and achieves in phase zero for target choice of VE activity to systematic and efficient analysis wishes to present conceptional pattern of available Web-Based VE 'Cost model analysis system (Cost Model Analysis System: CMAS)'.

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Antiproliferative Effect and Apoptotic Mechanism of Extract of Corydalis Yanhusuo on Human Hepatocarcinoma Cells (현호색(玄胡索)이 인체간암세포 증식억제 및 apoptosis 유발에 미치는 영향)

  • Oh, Myun- Taek;Eom, Hyun-Sup;Chi, Gyoo-Yong
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.21 no.6
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    • pp.1437-1449
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    • 2007
  • In this study, the effect of extract of Corydalis yanhusuo (ECT) used in Oriental medicine therapy was investigated on the cell growth and apoptosis of HepG2 human hepatoma cells. It was found that ECT could inhibit the cell growth effectively in a dose-dependent manner, which was associated with morphological change and apoptotic cell death such as formation of apoptotic bodies, DNA fragmentation and increased populations of apoptotic-sub G1 phase. And we observed the effects of ECT on loss of mitochondrial membrane potential (MMP), using the JC-1 probe by DNA flow cytometric analysis. Apoptosis of HepG2 cells by ECT was associated with a down-regulation of anti apoptotic Bcl-2 expression, inhibitor of apoptosis proteins (IAPs) expression and proteolytic activation of caspase-3 and caspase-9. However, ECT did not affect the pro-apoptotic Bax expression and activity of caspase-8. ECT treatment also concomitant degradation and /or inhibition of poly (ADP-ribose) polymerase (PARP), phospholipase C-1 ($PLC{\gamma}1$). Furthermore, ECT treatment caused a dose-dependent inhibition of iNOS and cyclooxygenase-2 (Cox-2). Additionally ECT have been implicated in the regulation of telomerase expression. ECT treatment induced the down-regulation of telomerase reverse transcriptase mRNA (hTERT) expression of HepG2 cells. Taken together, these findings suggest that ECT may be a potential chemotherapeutic agent for the control of HepG2 human hepatoma cells.

Analysis of Eddy Current Effect in Magnetic Resonance Imaging Using the Finite Element Method (유한요소법에 의한 자기공명영상시스템에서의 와전류 영향 분석)

  • Lee, Jeong-Han;Gang, Hyeon-Su;Jo, Min-Hyeong;Mun, Chi-Ung;Lee, Gang-Seok;Lee, Su-Yeol
    • Journal of Biomedical Engineering Research
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    • v.20 no.1
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    • pp.53-58
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    • 1999
  • Eddy current in MRI systems degrades gradient field linearity and distorts gradient waveform. When the waveform distortion is spatially variant, it is very difficult to perform special imaging techniques such as the echo planar imaging technique or the fast spin echo imaging technique. In this study, we have developed a new technique to estimate the distorted gradient waveforms at any points inside the imaging region using the finite element method. After obtaining the eddy-current-effect transfer function, which represents magnitude and phase characteristics of the gradient field at a particular point, we have used the transfer function to estimate the actual gradient waveforms at the point. To verify the proposed technique, we have compared the estimated gradient waveforms with the measured ones.

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Effect of Bevacizumab on Human Tenon's Fibroblasts Cultured from Primary and Recurrent Pterygium

  • Park, Young Min;Kim, Chi Dae;Lee, Jong Soo
    • The Korean Journal of Physiology and Pharmacology
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    • v.19 no.4
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    • pp.357-363
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    • 2015
  • The purpose of this study was to compare the inhibitory effect of bevacizumab on human Tenon's fibroblasts (HTFs) cultured from primary and recurrent pterygium. Cultured HTFs were exposed to 2.0, 5.0, 7.5, and 15.0 mg/mL concentration of bevacizumab for 24 hours. The 3-[4,5-dimethylthiazol- 2-yl]-2,5-diphenyl tetrazolium bromide and lactate dehydrogenase leakage assays were then performed to assess fibroblast metabolism and viability. The matrix metalloproteinase (MMP), procollagen type I C terminal propeptide (PIP), and laminin immunoassays were performed to examine extracellular matrix production. Changes in cellular morphology were examined by phase-contrast and transmission electron microscopy. Both metabolic activity and viability of primary and recurrent pterygium HTFs were inhibited by bevacizumab in a dose-dependent manner, especially at concentrations greater than 7.5 mg/mL. Both types of HTFs had significant decreases in MMP-1, PIP, and laminin levels. Distinctly, the inhibitory effect of bevacizumab on MMP-1 level related with collagenase in primary pterygium HTFs was significantly higher than that of recurrent pterygium. Significant changes in cellular density and morphology both occurred at bevacizumab concentrations greater than 7.5 mg/mL. Only primary pterygium HTFs had a reduction in cellular density at a bevacizumab concentration of 5.0 mg/mL. Bevacizumab inhibits primary and recurrent pterygium HTFs in a dose-dependent manner, especially at concentrations greater than 7.5 mg/mL. As the primary HTFs produces larger amounts of MMP-1 compared to recurrent HTFs, significant reduction in MMP-1 level in primary pterygium HTFs after exposure to bevacizumab is likely to be related to the faster cellular density changes in primary pterygium HTFs.

Leg Muscle Activity from the Perturbation of the Support during Gait (보행 시 지지 기반 급변에 대한 하지 근신경의 반응)

  • Shin, In-Sik;Chun, Young-Jin;Seo, Jung-Seok;Choi, Chi-Sun;Nam, Ki-Jung
    • Korean Journal of Applied Biomechanics
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    • v.17 no.3
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    • pp.147-154
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    • 2007
  • This study's purpose is to investigate the effects on leg muscle activity caused by perturbation, using a trapdoor system during the support phase of gait for healthy adults (n = 6, height $177.5{\pm}5.5cm$, weight $81.0{\pm}9.5kg$, age $30.0{\pm}3.3yrs$). The trapdoor had the functional ability of causing inversion or eversion. The release time for the trapdoor was specified for two times, 0.3 and 0.5 seconds after heel contact. While altering these variables, EMG was recorded for the leg muscles (rectus femoris, biceps femoris, vastus lateralis, tibialis anterior, gastrocnemius, soleus). The following conclusions were derived. The steptime was longer for the 0.5s eversion than 0.3s inversion condition. So in order to regain stability after the perturbation the unsupporting leg reached forward rapidly. This quick reflex can be observed through the center of pressure (COP) and its rapid change in direction. The gastrocnemius was activated throughout the total experiment. There was a low amount of activity recorded in the rectus femoris, vastus lateralis and tibialis anterior except for the condition of inversion 0.3s. For most of the conditions, the highest average EMG peak values were recorded during the condition of inversion 0.3s. The iEMG patterns were similar for the conditions of inversion 0.3s and eversion 0.3s. To cope with the rapid change in these conditions, the biceps femoris was activated. During the experiment except for the condition of normal gait, the activity of the soleus and gastrocnemius was relatively high. Therefore, to prevent injury from perturbation of the lower leg strengthening of the soleus and gastrocnemius is required. Likewise to prevent injury to the thigh strengthening for the biceps femoris.

On a Modified Structure of Planar Multiport Power Divider/Combiner at 2 GHz (평면 다수 입출력 전력 분배/결합회로의 2 GHz에서의 구조 수정 연구)

  • Han, Yong-In;Jo, Chi-Sung;Kim, Ihn-Seok
    • Journal of Advanced Navigation Technology
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    • v.6 no.4
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    • pp.279-290
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    • 2002
  • In this paper, tapered shape of multiport power divider/combiner modified for 2 GHz range from the model published by [10] is proposed. Parameters determining electrical property of the circuit structure have been analyzed by HFSS simulation. For input matching, balance of output signals and phase linearity at each output port, one circular hole has been etched out on the circuit surface. 1:2 and 1:3 power dividers/combiners designed by this study have been compared with the same circuits designed by the method of [10] in terms of S-parameters. As a result, it has been found that the modified structure of power divider/combiner have improved return loss more than 20 dB and another 18 dB, respectively, at 2 GHz.

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