• Polymer(Korea)
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• v.33 no.2
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• pp.118-123
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• 2009

Keratin contains regulatory molecules that can enhance neuronal cell activity. We fabricated keratin/ PLGA films using 0, 10, 20, and 50 wt% of keratin using solvent casting method. We measured the contact angle of each film and cell proliferation was assayed by counting the cells attached on the film. Adhered cell morphology was confirmed by scanning electron microscope. RT-PCR was conducted to evaluate the gene expression of NF, NSE, and S-100, the Schwann cell markers. The keratin content of 20 and 50 wt% provided higher wettability than PLGA. The 20 wt% keratin was better in cell adhesion and proliferation of SCs than other keratin/PLGA films. The phenotypic stability of SC was maintained with the keratin content of 10 and 20 wt%.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.9 no.7
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• pp.707-722
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• 2019

The concept of neighborhood parks has been used as the principle of forming a community in our society going through modern and contemporary times. The concept of neighborhood parks equipped with physical facilities has been discussed constantly regarding the roles and meanings of them. This study focuses on pocket parks which have been playing roles in improving environment through regeneration and forming regional communities based on that as neighborhood facilities. This author carried out field investigation on total 72 Hanpyeong Park and Hanpyeom Parks formed in the capital area and examined the significance of planning them and also their utility and residents and users' attachment to them through a survey. In this process, this researcher has been able to draw following conclusions. First, according to the demographic characteristics of users, there is significant difference found by groups in terms of their place attachment to the parks. This implies that difference in the major types of residences supplied these days influences their intention to experience ecological space. Second, according to their educational background, there is significant difference found by groups regarding their place attachment to the parks. Third, according to user behavior, there are differences found in their place attachment to the parks and also detailed differences found by groups in terms of the frequency of use and duration of stay.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.1
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• pp.28-34
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• 2019

Solar energy is one of the most abundant renewable energy sources on Earth but there are restrictions on the use of solar thermal energy due to the time-discrepancy between the solar-rich season and heating demand. In Europe and Canada, a seasonal solar thermal energy storage (SSTES), which stores the abundant solar heat in the summer and uses the heat for the winter heating load, is used. Recently, SSTES has been introduced in Korea and empirical studies are actively underway. In this study, a $2,000m^2$ flat plate type solar collector and $20,000m^2$ of borehole thermal energy storage (BTES) were studied for a greenhouse in Hwaseong City, which has a heating load of 2,164 GJ/year. To predict the dynamic performance of the system over time, it was simulated using the TRNSYS 18 program, and the solar fraction of the system with the control conditions was investigated. As a result, the solar BTES system proposed in this study showed an average solar fraction of approximately 60% for 5 years when differential temperature control was applied to both collecting solar thermal energy and discharging BTES. The proposed system simplified the configuration and control method of the solar BTES system and secured its performance.

• Applied Chemistry for Engineering
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• v.22 no.6
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• pp.599-604
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• 2011

In this study, we investigated the efficacy of ${\beta}$-cyclodextrin (${\beta}CD$) hydrorogel containing silk fibroin (SF) on healing burnt wound. Tosyl ${\beta}CD$ was conjugated to polyethyleneimine (PEI) using epichlorohydrin (EPI) as a cross-linker. The ${\beta}CD/PEI/SF$ hydrogel was applied on the back of mouse and then the efficacy of hydrogel was compared with both positive control group and negative control group. There was no wound healing efficacy showed neither in the drug loaded ${\beta}CD/PEI/SF$ hydrogel group nor in the drug unloaded ${\beta}CD/PEI/SF$ hydrogel group. On the other hand, in the positive control group, a significant reduction of the wound size after the usage of OTC hydrorogel was obtained. The burn-healing histological result showed a similar phenomenon. After hematoxylin-eosin staining the skin induced by burning, and the epithelial growth observed in the dermis, the efficacy of ${\beta}CD/PEI/SF$ hydrogel in healing burnt wound could not be clearly identified.

• Korean Chemical Engineering Research
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• v.60 no.3
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• pp.386-391
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• 2022

This study is about a technique for obtaining collagen by extracting fat by treating collagen-containing liposuction effluent in the presence of supercritical fluid. Using a supercritical solvent, a collagen extract could be obtained from animal-derived fat in a short time (about 6 hours), and about 2-3% of collagen by mass compared to the raw material could be obtained. The presence of collagen in the extract obtained by supercritical extraction was confirmed by SDS-PAGE, and it was confirmed that it was type 1 collagen having a relatively large molecular weight. In addition, the growth factors of IGF-1, bFGF, VEGF and NGF were analyzed to find out which growth factors were present in the collagen obtained by supercritical extraction, and it was found that these growth factors were contained in the extract. There was no significant difference in DNA content per mg of sample before and after supercritical treatment. Further in-depth studies are likely to be needed on decellularization technology using the supercritical process. In conclusion, the extracellular matrix obtained through the solvent extraction process using a supercritical fluid contains growth factors above a certain amount even after decellularization and removal of fat, so that it was found that not only biocompatibility is greatly increased, but also tissue regeneration can be rapidly induced.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.2
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• pp.307-313
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• 2022

As the development of renewable energy expands internationally to cope with global warming and climate change, the share of wind power generation has been gradually increasing. Although wind farms can produce electric power for 24 h a day compared to solar power plants, Their interfere with the operation of nearby radars or communication equipment must be analyzed because large-scale wind power turbines are installed. This study analyzed whether a land radio station can receive sufficient signals when a ship sailing outside the offshore wind farm transmits distress signals on the VHF band. Based on the geographic information system digital map around the target area, wind turbine CAD model, and wind farm layout, the area of interest and wind farm were modeled to enable numerical analysis. Among the high frequency analysis techniques suitable for radio wave analysis in a wide area, a dedicated program applying physical optics (PO) and shooting and bouncing ray (SBR) techniques were used. Consequently, the land radio station could receive the electromagnetic field above the threshold of the VHF receiver when a ship outside the offshore wind farm transmitted a distress communication signal. When the line of sight between the ships and the land station are completely blocked, the strength of the received field decreases, but it is still above the threshold. Hence, although a wind farm is a huge complex, a land station can receive the electromagnetic field from the ship's VHF transmitter because the wave length of the VHF band is sufficiently long to have effects such as diffraction or reflection.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2020.08a
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• pp.82-82
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• 2020

염증 (Inflammation)은 물리적인 상처나 세균감염이 되었을 때 손상된 조직을 재생하고 신체를 방어하기 위해 일어나는 선천성 면역반응으로 알려져 있다. 주로 선천면역을 담당하는 대식세포는 lipopolysaccharide, reactive oxygen species와 cytokine 등에 의해 활성화되어 tumor necrosis factor-α. interleukin-1β, interleukin-6 등 염증인자들의 생성에 관여한다. 특히, 산화질소는 superoxide 음이온과 쉽게 반응하고 peroxynitrite와 같은 독성이 강한 산화제를 생성하여 단백질 및 지질의 과산화를 유도하고 세포독성을 일으키는 것으로 보고되고 있다. 따라서 본 연구에서는 항산화 및 항염증 소재를 탐색하기 위해 오미자 (Schisandra chinensis), 꾸지뽕 (Cudrania tricuspidata)을 이용하여 항산화 활성을 평가하고자 하였으며, 세포주를 활용한 세포독성 및 항염증 활성을 확인하고자 하였다. 본 연구는 전북 순창군에서 재배된 오미자, 꾸지뽕을 열 건조(60℃) 통해 건조한 후 분말화하였다. 최적 추출 조건 선정을 위해 다양한 용매 (열수, 증류수, 주정 20, 40, 60%), 온도 (25, 40, 60, 80℃) 및 시간 (1, 2, 3, 4, 5 h) 조건에서 추출된 추출물의 총 폴리페놀 함량을 비교함으로써 최적 조건을 선정하였다. 오미자와 꾸지뽕의 DPPH 및 ABTS radical 소거 활성, 총 플라보노이드 함량을 확인하여 항산화능 및 기능성 성분 함량을 평가하였다. 또한 대식세포주인 Raw 264.7을 활용하여 MTT assay, 산화질소 생성 억제 활성을 확인하여 세포독성 및 항염증 활성을 평가하였다. 실험 결과, 오미자 및 꾸지뽕은 각각 주정 40%, 60℃ 그리고 증류수, 60℃에서 추출 시 가장 높은 총 폴리페놀 함량 (약 98.3 mg GAE/g 및 88.2 mg GAE/g)을 함유하며, DPPH 라디칼 소거 활성은 약 44.6% 및 24.4%, ABTS 라디칼 소거 활성은 약 30.3% 및 40.8%로 확인되었다. 총 플라보노이드 함량은 약 21.80 mg QE/g 및 35.68 mg QE/g으로 확인되었다. 또한 오미자 및 꾸지뽕 기능성 추출물을 100 ug/mL 처리 시 세포 독성이 나타나지 않는 것으로 확인되었으며, NO 생성량을 약 56.3% 및 21.7% 저감시켜 항염증 효능을 나타내는 것으로 확인되었다.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2020.08a
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• pp.84-84
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• 2020

염증 (Inflammation)은 병원체, 손상된 세포, 자극물질 등으로 인한 손상에 대해 작용하여 조직이나 장기의 손상을 재생하는 작용으로써 신체 방어 기전들 가운데 매우 중요한 역할을 하는 것으로 알려져 있다. 이러한 염증반응이 과다할 경우 각종 염증성 질환 혹은 암 등을 유발하는 원인으로 발전할 수 있어 항염증제의 개발은 전 세계적으로 중요시되고 있다. 선천적 면역을 담당하는 대식세포는 lipopolysaccharide(LPS), 활성산소 (ROS) 등에 의해 자극되어 염증인자 생성에 관여한다. 따라서 본 연구에서는 항염증 소재 개발을 목표로 하며, 국내 천연소재를 활용한 기능성 항염증 소재로 전북 순창군에서 재배된 초석잠(Stachys Sieboldii MIQ.)과 돼지감자 (Helianthus tuberosus L.)를 이용하여 항산화 활성을 평가하고자 하였으며, 대식세포주를 활용한 세포독성 및 항염증 활성에 대한 효능을 확인하고자 하였다. 본 연구는, 전북 순창 지역에서 재배 된 초석잠과 돼지감자를 사용하여 각 조건의 추출 용매, 온도, 시간별 추출물의 Total polyphenol 함량 평가를 통한 최적 추출조건 선정을 진행하고, 선정된 추출조건의 추출물의 항산화 활성을 측정하기 위해 DPPH & ABTS radical scavenging activity 분석 및 Total flavonoids 함량 분석을 통해 항산화 효능 평가를 진행하였다. 또한 항염증 소재로의 활용을 위해 대식세포인 Raw 264.7을 사용하여 농도별 MTT assay를 진행하여 세포독성 평가를 진행하였고, Nitric oxide (NO) 생성억제 효능을 확인하여 항염증 활성을 평가하였다. 실험 결과, Total polyphenol 함량 분석을 통해 최적 추출조건이 선정된 초석잠 (25℃, 주정 60%, 3 h), 돼지감자 (25℃, 주정 40%, 1 h)은 최적 조건에서 약 58 mg GAE/g 및 158 mg GAE/g의 총 폴리페놀 함량을 보였으며, DPPH & ABTS radical scavenging activity 및 Total flavonoids 함량 분석한 결과, 초석잠이 돼지감자보다 더 높은 항산화 활성을 나타내었다. 대식세포 실험에서의 추출물 처리군의 세포독성 측정 결과, 100 ug/mL 이내의 농도에서 독성활성이 나타나지 않음을 확인하였고, Nitric oxide (NO) 생성 억제활성 측정을 통해 LPS 처리군 대비 접종량 100 ug/mL 기준 각각 초석잠 약 47%, 돼지감자 약 49% 수준의 항염증 활성을 확인하였다.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.6
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• pp.1143-1150
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• 2023

The global climate crisis and the implementation of low-carbon policies have led to a growing interest in renewable energy and a growing number of related industries. Among them, solar power is attracting attention as a representative eco-friendly energy that does not deplete and does not emit pollutants or greenhouse gases. As a result, the supplement of solar power facility is increasing all over the world. However, solar power is easily affected by the environment such as geography and weather, so accurate solar power forecast is important for stable operation and efficient management. However, it is very hard to predict the exact amount of solar power using statistical methods. In addition, the conventional prediction methods have focused on only short- or long-term prediction, which causes to take long time to obtain various prediction models with different prediction horizons. Therefore, this study utilizes a many-to-many structure of a recurrent neural network (RNN) to integrate short-term and long-term predictions of solar power generation. We compare various RNN-based very short- and long-term prediction methods for solar power in terms of MSE and R² values.

• The Journal of the Acoustical Society of Korea
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• v.29 no.7
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• pp.458-467
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• 2010

In this paper, a new audio reproduction system was developed in which the cross-talk signals would be reasonably cancelled at an arbitrary listener position. To adaptively remove the cross-talk signals according to the listener's position, a method of tracking the listener position was employed. This was achieved using the two microphones, where the listener direction was estimated using the time-delay between the two signals from the two microphones, respectively. Moreover, room reverberation effects were taken into consideration where linear prediction analysis was involved. To remove the cross-talk signals at the left-and right-ears, the paths between the sources and the ears were represented using the KEMAR head-related transfer functions (HRTFs) which were measured from the artificial dummy head. To evaluate the usefulness of the proposed listener tracking system, the performance of cross-talk cancellation was evaluated at the estimated listener positions. The performance was evaluated in terms of the channel separation ration (CSR), a -10 dB of CSR was experimentally achieved although the listener positions were more or less deviated. A real-time system was implemented using a floating-point digital signal processor (DSP). It was confirmed that the average errors of the listener direction was 5 degree and the subjects indicated that 80 % of the stimuli was perceived as the correct directions.