• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.9
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• pp.548-556
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• 2014

To cope with recently increasing demand for data traffics, heterogeneous networks have been actively studied, where small cells are deployed within a macro cell coverage with the same frequency band. To mitigate the interference from the macro cell to small cells, an enhanced Inter-cell Interference Coordination (eICIC) technique has been proposed, where ABS (Almost Blank Subframe) is used in time domain. However, there is a waste of resource since no data is transmitted in a macro-cell in ABS. In this paper, we propose a new interference management method by using a 3D sector beam based on Active Antenna System (AAS), where Genetic Algorithm (GA) is applied to reduce the antenna gain toward a small-cell. With the proposed scheme, the macro-cell and small cells can transmit data at the same time with the AAS antenna pattern generating reduced interference to small cells. The performance of the proposed scheme is evaluated by using an LTE-Advanced system level simulator.

• The Korean Journal of Zoology
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• v.38 no.3
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• pp.330-339
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• 1995

In Helice tridens tridens, hylaine cells, small granulocytes, and large granulocytes were identified. Features of hyaline cells include a large nucleus in proportion to the cytoiplasm, and weak electron-dense granules of oval shape and vesicles, and endoplasmic reticulum (ER) in the cytoplasm. Small granulocytes have smaller nucleus than that of the hyaline cells, well-developed ER, Golgi complex, and small, round and electron-dense granules in the cytoplasm. Large granulocytes contain large and electron dense granules (ahout 1 $\mu$m) that fused small granules. Hemocytes of Helice tridens tridens differentiated from hyaline cell to large granulocyte granules of hyaline cells have lysosome and make small vesicles from nuclear envelopes. While these vesicles pass through the Golgi complex, they are filled with electron dense matetials, and then fused with the small granules. They eventually matured into large granules. All of hemocytes have the glycogen particles. In the large granulocytes heterogeneouse granules were supposed to occur by disappearance of granules.

• ETRI Journal
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• v.40 no.1
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• pp.51-60
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• 2018

In Long Term Evolution (LTE) cellular networks, the transmit power control (TPC) mechanism consists of two parts: the open loop (OL) and closed loop. Most cellular networks consider OL/TPC because of its simple implementation and low operation cost. The analysis of OL/TPC parameters is essential for efficient resource management from the cellular operator's viewpoint. In this work, the impact of the OL/TPC parameters is investigated for homogeneous small cells and heterogeneous small-cell/macrocell network environments. A mathematical model is derived to compute the transmit power at the user equipment, the received power at the eNodeB, the interference in the network, and the received signal-to-interference ratio. Using the analytical platform, the effects of the OL/TPC parameters on the system performance in LTE networks are investigated. Numerical results show that, in order to achieve the best performance, it is appropriate to choose ${\alpha}_{small}=1$ and $P_{o-small}=-100dBm$ in a homogenous small-cell network. Further, the selections of ${\alpha}_{small}=1$ and $P_{o-small}=-100dBm$ in the small cells and ${\alpha}_{macro}=0.8$ and $P_{o-macro}=-100dBm$ in the macrocells seem to be suitable for heterogeneous network deployment.

• Electronics and Telecommunications Trends
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• v.37 no.2
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• pp.83-95
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• 2022

5G goes beyond people to serve indoor and outdoor companies and industries, as well as campuses such as halls, industrial complexes, educational institutions, stadiums, dense urban areas, rural areas, and government institutions. Therefore, a new approach to small cells is needed. Accordingly, 3GPP and Small Cell Forum are researching 5G small cell architecture; 3GPP, Small Cell Forum, and 5G Alliance for Connected Industries and Automation are also researching private networks tailored to meet the specific requirements of various companies and local governments. In particular, in the UK, a small cell-based technology is required for realizing the Joint Operator Technical Specifications-Neutral Host In-Building specification to cost-effectively secure indoor coverage. Further, the research on the SON(Self-Organizing Network) technology for small cells in 5G, where commercialization has begun, is required. The 5G-based small cell structure, private network, and Neutral Host In-Building and SON reviewed in this study are at the initial research stages; therefore, additional research is needed to secure the competitiveness of the small cell technology in 5G and Beyond 5G.

• Natural Product Sciences
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• v.20 no.3
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• pp.211-215
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• 2014

Opuntia humifusa, also called as Cheonnyuncho, is a cactus widely cultivated in southern regions of Korea. It has been known to have diverse biological activities, but most of the studies were performed with the MeOH extracts or solvent-partitioned fractions. Furthermore, the efforts to identify the responsible compounds for the biological activities are very limited. In this study, we tested the inhibitory effect of extracts and solvent-partitioned fractions of O. humifusa against LPS-induced nitric oxide (NO) production in Raw264.7 cells. The butanol fractions of O. humifusa efficiently inhibited the production of NO in Raw264.7 cells, but it was not due to the reduction of cell viability. Bioassay-guided isolation of butanol fractions of O. humifusa allowed the isolation of three flavonoids isorhamnetin 3-O-${\beta}$-$\small{D}$-galactosyl-4'-O-${\beta}$-$\small{D}$-glucoside (1), isorhamnetin 3,4'-di-O-${\beta}$-$\small{D}$-glucoside (2) and isorhamnetin 3-O-${\beta}$-$\small{D}$-(6-O-${\alpha}$-$\small{L}$-rhamnosyl)glucoside (3), and one lignan syringaresinol O-${\beta}$-$\small{D}$-glucopyranoside (4). Among them, isorhamnetin 3-O-${\beta}$-$\small{D}$-galactosyl-4'-O-${\beta}$-$\small{D}$-glucoside (1) and isorhamnetin 3,4'-di-O-${\beta}$-$\small{D}$-glucoside (2) exhibited the moderate inhibitory effects against LPS-induced NO production. This is the first time to report anti-inflammatory effects of these compounds.

• Journal of Microbiology and Biotechnology
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• v.16 no.3
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• pp.475-479
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• 2006

Gentisyl alcohol isolated from Penicillium sp. has an antioxidative activity, protecting cells from oxidative stresses. From our in vitro angiogenesis assays with bovine aortic endothelial cells (BAECs), gentisyl alcohol was newly identified as a pro-angiogenic small molecule that induces new blood vessel formation of the cells. Gentisyl alcohol stimulated the proliferation of BAECs in a dose-dependent manner. Moreover, it induced in vitro angiogenesis of BAECs such as invasiveness, migration, and tube formation of the endothelial cells. Effects of gentisyl alcohol on invasion and tube formation were also dose-dependent. These results demonstrate that gentisyl alcohol could affect the angiogenic phenotypes of endothelial cells and be developed as a new small molecule with pro-angiogenic activity.

• Applied Microscopy
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• v.29 no.1
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• pp.83-94
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• 1999

The ultrastructure of small arterioles and capillaries in the lumbrical muscles of rat digits were studied by electron microscopy and following results were obtained. 1. The diameter of small arterioles of rat digits were $12\sim20{\mu}m$, and it was relatively smaller than human $(30\sim35{\mu}m)$. 2. All the endothelial cells of small arterioles and capillaries in the lumbrical muscles of rat digits were continuous type, and they had typical morphological characteristics of continuous endothelial cells : numerous cytoplasmic pinocytic vesicles and many tight junctions between the endothelial cells. 3. In the small arterioles subendothelial layers were irregularly spaced beneath the basal lamina, and membrane to membrane contacts were found between the endothelial cells and smooth muscle cells. 4. Pericytes were often found nearby capillary endothelium, and their cytoplasmic processes surrounded part of endothelial cells. They were enclosed by basal lamina. 5. Smooth muscle cells in tunica media of small arterioles were only one layered, that is, they were terminal arterioles. Sarcoplasm of smooth muscle cell was divided to 2 areas; homogeneous or filamentous area and non-homogeneous perinuclear area. 6. The tunica adventitia contained fibroblasts with extremely attenuated cytoplasmic processes and collagen fibirls.

• Tuberculosis and Respiratory Diseases
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• v.48 no.3
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• pp.324-330
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• 2000

Objective : Lung cancer arises after a series of morphological changes, which take several years to progress from normal epithelium to invasive cancer. Multiple molecular changes and growth factor production have been documented in lung cancers, both small cell and non-small cell types. Insulin-like growth factors(IGFs) are important mitogenic and anabolic peptides, both in vivo and in vitro, and are thought to be significant autocrine-paracrine factors involved in normal and malignant cell proliferation. In this study, the degree of expression of IGF-1 on the immunohistochemical staining in human non-small cell lung cancer(NSCLC) cells and small cell lung cancer (SCLC) cells were investigated. Methods : Immunohistochemical staining for IGF-1 was performed in 15 cases of small cell carcinoma, 15 cases of squamous cell carcinoma, 15 cases of adenocarcinoma, and 12 cases of bronchoalveolar carcinoma. Results : The expression of IGF-1 on the immunohistochemical staining significantly increased in NSCLC cells than in SCLC cells. Conclusion : These results suggest the expression of IGF-1 in human lung cancer cells. The immunohistochemical staining of IGF-1 in lung cancer cell lines may assist in the differentiation of NSCLC and SCLC.

• Proceedings of the KSAR Conference
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• 2001.03a
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• pp.69-69
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• 2001

The cell cycle phase in which donor nuclei exist prior to nuclear transfer is an important factor governing developmental rates of reconstituted embryos. It was suggested that quiescent G0 and cycling G1 cells could support normal development of reconstituted embryos. In a quest of optimized donor nuclei treatment prior to nuclear transfer, this study was undertaken to examine the cell cycle characteristics of bovine fetal and adult somatic cells when cultured under a variety of culture treatments and the cell cycle change with the lapse of time after trypsinization. This was archived by measuring the DNA content of cells using flow cytometry, Cultured fetal fibroblast cells, adult skin and muscle cells, and cumulus cells were divided by 3 culture treatments; 1) grown to 60-70% confluency (cycling), 2) serum starved culture, 3) culture to confluency. Trypsinized cells were fixed by 70% ethanol and stained with propidium iodide. For one experiment, trypsinized cells were resuspended in DMEM＋10% FBS and incubated for 1.5, 3 and 6 h with occasional shaking before ethanol fixation. Cell cycle phases were determined by flow cytometry enabling calculation of percentages of G0＋G1, S and G2＋M. The majority of cells were in G0＋Gl stage regardless of origin of cells. Cultures that were serum starved or cultured to confluency contained significantly (P<0.05) higher percentages of cells in G0＋G1 (89.5-95.4%). For every cell lines and culture treatments, percentages of cells in existing in G0＋G1 increased with decreasing of the cell size from large to small. In the serum starved and confluency groups, about 98% of small cells were in G0＋G1 Serum starved culture contained higher percentages of small-sized cells (38.5-66.9%) than cycling and confluent cultures regardless of cell lines (P<0.05). After trypsinization of fetal fibroblast and adult skin cells that were serum starved and cultured to confluency, the percentages of cells in G0＋G1 significantly increased by incubation for 1.5(95.7-99.5%) and 3.0 h (95.9-98.6%). The results suggest that the efficient synchronization of bovine somatic cells in G0＋G1 for nuclear transfer can be established by incubation for a limited time period after trypsinization of serum starved or confluent cells.

• Current Photovoltaic Research
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• v.2 no.2
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• pp.48-52
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• 2014

A photovoltaic cell of CuPc:P3HT:PCBM was introduced to extend the light absorption in the visible wavelength between 300~500 and 550~800 nm. By fabricating the photovoltaic cells of ITO / PEDOT:PSS / CuPc:P3HT:PCBM / BCP / Al with small-molecular and polymer donating materials blended layer, we demonstrated a high PCE of 4.20% with high Jsc of $10.05mA/cm^2$. This performance of photovoltaic cell with the blended layer of small-molecular and polymer can be competitive with that of tandem cells.