• 천문학회보
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• 제41권2호
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• pp.62.3-63
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• 2016

We studied the young stellar populations of star-forming (SF) regions in M33 based on the Galaxy Evolution Explorer (GALEX) ultraviolet (UV) imaging data. The SF regions are defined from far-UV data with various thresholds. We examined the reddening and spatial distribution of hot massive stars within SF regions from Hubble Space Telescope multi-band survey and Local Group Galaxy Survey (LGGS) data. The H-alpha sources from the LGGS are used for comparing with the spatial distribution of SF regions. The GALEX UV flux measurements of SF regions are used to derive their ages and masses. We also estimated the size and density of SF regions. The younger and compact SF regions are often arranged within older and sparser SF complexes. The results allow us to understand the hierarchical star formation and recent evolution of M33.

• 한국재료학회지
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• 제19권2호
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• pp.68-72
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• 2009

This study investigated dry etching of acrylic in capacitively coupled $SF_6$, $SF_6/O_2$ and $SF_6/CH_4$ plasma under a low vacuum pressure. The process pressure was 100 mTorr and the total gas flow rate was fixed at 10 sccm. The process variables were the RIE chuck power and the plasma gas composition. The RIE chuck power varied in the range of $25{\sim}150\;W$. $SF_6/O_2$ plasma produced higher etch rates of acrylic than pure $SF_6$ and $O_2$ at a fixed total flow rate. 5 sccm $SF_6$/5 sccm $O_2$ provided $0.11{\mu}m$/min and $1.16{\mu}m$/min at 25W and 150W RIE of chuck power, respectively. The results were nearly 2.9 times higher compared to those at pure $SF_6$ plasma etching. Additionally, mixed plasma of $SF_6/CH_4$ reduced the etch rate of acrylic. 5 sccm $SF_6$/5 sccm $CH_4$ plasma resulted in $0.02{\mu}m$/min and $0.07{\mu}m$/min at 25W and 150W RIE of chuck power. The etch selectivity of acrylic to photoresist was higher in $SF_6/O_2$ plasma than in pure $SF_6$ or $SF_6/CH_4$ plasma. The maximum RMS roughness (7.6 nm) of an etched acrylic surface was found to be 50% $O_2$ in $SF_6/O_2$ plasma. Besides the process regime, the RMS roughness of acrylic was approximately $3{\sim}4\;nm$ at different percentages of $O_2$ with a chuck power of 100W RIE in $SF_6/O_2$ plasma etching.

• 대한의생명과학회지
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• 제11권3호
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• pp.327-332
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• 2005

Sf21 cells become popular as the host permissive cell line to support the baculovirus AcNPV replication and protein synthesis. The cells grow well on TC-100 medium that contains $0.1\%$ D-glucose as the major carbon source, strongly suggesting the presence of endogenous glucose transporters. However, unlike human glucose transporters, very little is known about the characteristics of the endogenoussugar transporter(s) in Sf21 cells. Thus, some kinetic properties of the sugar transport system were investigated, involving the uptake of 2-deoxy-D-glucose (2dG1c). In order to obtain a true measure of the initial rate of uptake, the uptake of $[^3H]2dGlc$ from both low $(100{\mu}M)$ and high (10 mM) extracellular concentrations was measured over periods ranging from 30 sec to30 min. The data obtained indicated that the uptake was linear for at least 2 min at both concentrations, suggesting that measurements made over a 1min time course would reflect initial rates of the jexpse uptake. To determine $K_m\;and\;V_{max}$ of the endogenous glucose transporter(s) in Sf21 cells, the uptake of 2dG1c was measured over a range of substrate concentrations $(50{\mu}M\~10mM)$ 2dG1c uptake by the Sf21 cells appeared to involve both saturable and non-saturable (or very low affinity) components. A saturable transport system for 2dG1c was relatively high, the $K_m$ value for uptake being < 0.45 mM. The $V_{max}$ value obtained for 2dG1c transport in the Sf21 cells was about 9.7-folds higher than that reported for Chinese hamster ovary cells, which contain a GLUT1 homologue. Thus, it appeared that the transport activity of the Sf21 cells was very high. In addition, the Sf21 glucose transporter was found to have very low affinity for cytochalasin B, a potent inhibitor of human erythrocyte glucose transporter

• 대한의생명과학회지
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• 제12권1호
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• pp.17-22
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• 2006

The baculovirus expression system is a powerful method for producing large amounts of the human erythrocyte-type glucose transport protein, heterologously. Characterization of the expressed protein is expected to show its ability to transport sugars directly. To achieve this, it is a prerequisite to know the properties of the endogenous sugar transport system in Spodoptera frugiperda Clone 21 (Sf21) cells, which are commonly employed as a host permissive cell line to support the baculovirus replication. The Sf21 cells can grow well on TC-100 medium that contains 0.1% D-glucose as the major carbon source, strongly suggesting the presence of endogenous glucose transport system. However, unlike the human glucose transport protein that has a broad substrate and inhibitor specificity, very little is known about the nature of the endogenous sugar transport system in Sf21 cells. In order to characterize further the inhibitor recognition properties of the Sf21 cell transporter, the ability of phloretin, cytochalasin B and D-fructose to inhibit 2-deoxy-D-glucose (2dGlc) transport was examined by measuring inhibition constants $(K_i)$. The $K_i's$ for reversible inhibitors were determined from plots of uptake versus inhibitor concentration. The 2dGlc transport in the Sf21 cells was very potently inhibited by phloretin, the aglucone of phlorizin with a $K_i$ similar to the value of about $2{\mu}M$ reported for inhibition of glucose transport in human erythrocytes. However, the Sf21 cell transport system was found to differ from the human transport protein in being much less sensitive to inhibition by cytochalasin B (apparent $K_i$ approximately $10\;{\mu}M$). In contrast, It is reported that the inhibitor binds the human erythrocyte counterpart with a $K_d$ of approximately $0.12\;{\mu}M$. Interestingly, the Sf21 glucose transport system also appeared to have high affinity for D-fructose with a $K_i$ of approximately 5mM, contrasting the reported $K_m$ of the human erythrocyte transport protein for the ketose of 1.5M.

• 한국지형학회지
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• 제25권1호
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• pp.67-80
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• 2018

This study used aerial and terrestrial images to build a three-dimensional model of cliffs located in Pado beach using SfM (Structure from Motion) techniques. Using both images, the study purposed to reduce the shadow areas that were found when using only aerial images. Accuracy of the two campaigns was assessed by root mean square error, and monitored by M3C2 (Multiscale Model to Model Cloud Comparison) method. The result of the M3C2 in closed areas such as sea cave and notch did not express the landforms partly. However, eroded debris on sea cliffs were detected as eroded area by M3C2, as well as in captured pictures by multi-camera. The result of this study showed the applicability of multi-camera and SfM in monitoring changes of sea cliffs.

• Asian-Australasian Journal of Animal Sciences
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• 제32권12호
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• pp.1844-1853
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• 2019

Objective: We investigated how pituitary adenylate cyclase-activating polypeptide (PACAP) affects embryonic development during pre-in vitro maturation (pre-IVM) using porcine oocytes isolated from small follicles. Methods: We divided the follicles into the experimental groups by size (SF, small follicles; MF, medium follicles) and treated with and without PACAP and cultured for 18 hours (PreSF[-]PACAP; without PACAP, Pre-SF[+]PACAP; with PACAP) before undergoing IVM. The gene expression related to extracellular matrix formation (amphiregulin, epiregulin, and hyaluronan synthase 2 [HAS2]) and apoptosis (Bcl-2-associated X [BAX], B-cell lymphoma 2, and cysteine-aspartic acid protease 3) was investigated after maturation. The impact on developmental competence was assessed by the cleavage and blastocyst rate and total cell number of blastocysts in embryos generated from parthenogenesis (PA) and in vitro fertilization (IVF). Results: Cleavage rates in the Pre-SF(+)PACAP after PA were significantly higher than SF and Pre-SF(-)PACAP (p<0.05). The cleavage rates between MF and Pre- SF(+)PACAP groups yielded no notable differences after IVF. Pre-SF(+)PACAP displayed the higher rate of blastocyst formation and greater total cell number than SF and Pre-SF(-)PACAP (p<0.05). Cumulus cells showed significant upregulation of HAS2 mRNA in the Pre-SF(+)PACAP compared to the SF (p<0.05). In comparison to other groups, the Pre-SF(+)PACAP group displayed a downregulation in mRNA expression of BAX in matured oocytes (p<0.05). Conclusion: The PACAP treatment during pre-IVM improved the developmental potential of porcine oocytes derived from SF by regulating cumulus expansion and apoptosis of oocytes.

• 한국농공학회논문집
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• 제66권3호
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• pp.1-14
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• 2024

Gaining an accurate 3D stream geometry has become feasible with Unmanned Aerial Vehicle (UAV), which is crucial for better understanding stream hydrodynamic processes. The objective of this study was to investigate series of filters to remove stream vegetation and propose the best method for generating Digital Terrain Models (DTMs) using UAV-based point clouds. A stream reach approximately 500 m of the Bokha stream in Icheon city was selected as the study area. Point clouds were obtained in August 1st, 2023, using Phantom 4 multispectral and Zenmuse L1 for Structure from Motion (SfM) and Light Detection And Ranging (LiDAR) respectively. Three vegetation filters, two morphological filters, and six composite filters which combined vegetation and morphological filters were applied in this study. The Mean Absolute Error (MAE) and Root Mean Square Error (RMSE) were used to assess each filters comparing with the two cross-sections measured by leveling survey. The vegetation filters performed better in SfM, especially for short vegetation areas, while the morphological filters demonstrated superior performance on LiDAR, particularly for taller vegetation areas. Overall, the composite filters combining advantages of two types of filters performed better than single filter application. The best method was the combination of Progressive TIN (PTIN) and Color Indicies of Vegetation Extraction (CIVE) for SfM, showing the smallest MAE of 0.169 m. The proposed method in this study can be utilized for constructing DTMs of stream and thus contribute to improving the accuracy of stream hydrodynamic simulations.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2001년도 학술대회논문집
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• pp.145-149
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• 2001

The most of faults in gas insulation of power facilities are caused by partial discharge. Therefore we simulated partial discharge and measured the radiated electromagnetic wave emitted from partial discharge in SF$_{6}$ gas by biconical antenna. This paper describes time delay and electric fields pulse characteristics of radiated electromagnetic waves with distance(1[m], 3[m], 5[m]) between antenna and discharge source.e.

• Tissue Engineering and Regenerative Medicine
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• 제15권6호
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• pp.781-791
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• 2018

BACKGROUND: Glucosamine hydrochloride (GlcN HCl) has been shown to inhibit cell growth and matrix synthesis, but not with N-acetyl-glucosamine (GlcNAc) supplementation. This effect might be related to an inhibition of critical growth factors (GF), or to a different metabolization of the two glucosamine derivatives. The aim of the present study was to evaluate the synergy between GlcN HCl, GlcNAc, and GF on proliferation and cartilage matrix synthesis. METHOD: Bovine chondrocytes were cultivated in monolayers for 48 h and in three-dimensional (3D) chitosan scaffolds for 30 days in perfusion bioreactors. Serum-free (SF) medium was supplemented with either growth factors (GF) $TGF-{\beta}$ ($5ng\;mL^{-1}$) and IGF-I ($10ng\;mL^{-1}$), GlcN HCl or GlcNAc at 1mM each or both. Six groups were compared according to medium supplementation: (a) SF control; (b) SF + GlcN HCl; (c) SF + GlcNAc; (d) SF + GF; (e) SF + GF + GlcN HCl; and (f) SF + GF + GlcNAc. Cell proliferation, proteoglycan, collagen I (COL1), and collagen II (COL2) synthesis were evaluated. RESULTS: The two glucosamines showed opposite effects in monolayer culture: GlcN HCl significantly reduced proliferation and GlcNAc significantly augmented cellular metabolism. In the 30 days 3D culture, the GlcN HCl added to GF stimulated cell proliferation more than when compared to GF only, but the proteoglycan synthesis was smaller than GF. However, GlcNAc added to GF improved the cell proliferation and proteoglycan synthesis more than when compared to GF and GF/GlcN HCl. The synthesis of COL1 and COL2 was observed in all groups containing GF. CONCLUSION: GlcN HCl and GlcNAc increased cell growth and stimulated COL2 synthesis in long-time 3D culture. However, only GlcNAc added to GF improved proteoglycan synthesis.

• 한국정보통신학회논문지
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• 제20권3호
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• pp.527-535
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• 2016

3차원 형상과 모션을 추정하기 위한 통계학적 최적화 알고리즘들이 다양하게 개발되고 있다. 그렇지만 통계적 접근은 카메라의 기하학적 위치나 관측시야각 등의 설정에 따른 SfM(Shape form Motion)의 민감한 영향을 분석하는데는 한계가 있다. 본 논문은 SfM의 모호성을 예측하기 위해 카메라 촬영 구성 요소를 이용하여 관측행렬의 불확실성을 정량적으로 추정할 수 있는 방법을 제안한다. 제안한 방법은 SfM 알고리즘의 최종적인 복원 성능을 예측하는데도 매우 효과적인 방법이다. 또한 합리적인 복원 결과를 기대할 수 있도록 카메라 촬영 구성을 설정하기 위한 직접적인 가이드라인을 제공할 수 있다는 점에서 중요하다. 실험결과는 이러한 카메라 촬영 구성을 이용하여 관측행렬의 불확실성에 대한 정량적 추정을 실험적으로 검증하고 본 알고리즘의 효율성을 확인한다.