• 한국ITS학회 논문지
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• 제11권3호
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• pp.81-91
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• 2012

최근 기후변화에 따른 위기감으로 인해 세계 각국은 화석연료의 자동차를 전기자동차로 대체하기 위한 노력을 기울이고 있다. 정부는 2020년까지 소형차의 10% 이상을 전기자동차 보급 목표로 설정하였고 '주택건설 기준 등에 관한 규정'을 개정하여 전기자동차 충전설비를 공동주택의 부대설비에 포함시키는 등 충전 인프라 구축에도 노력하고 있다. 공동주택에서 전기자동차의 충전 인프라 및 주차 공간 등의 확보는 전기자동차 보급에 있어 핵심이 되지만, 이들에 대한 합리적 용량 산정 등에 필요한 전기자동차의 수요예측 연구는 미미한 상태이다. 이를 위해 본 연구는 수도권의 공동주택 거주자(분양과 임대 구분)를 대상으로, 통계자료의 시계열분석과 선호도 결과를 이용하여 전기자동차 수요를 예측하였다. 그 결과 2020년 공동주택 거주자의 전기자동차 비율은 임대아파트의 경우 6～21%, 분양아파트는 21～39% 수준이며, 이들의 사용을 지원할 최대전력량은 1,000가구 1일 기준으로 임대아파트 4,200kwh, 분양아파트 7,800kwh로 예측되었다.

• Journal of Electrical Engineering and Technology
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• 제9권2호
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• pp.452-460
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• 2014

Due to increased concerns for rising oil prices and environmental problems, various solutions have been proposed for solving energy problems through tightening environmental regulations such as those regarding $CO_2$ reduction. Among them, Electrical Vehicles (EVs) are evaluated to be the most realistic and effective approach. Accordingly, research and development on EVs and charging infrastructures are mainly proceeding in developed countries. Since EVs operate using electric energy form a battery, they must be connected to the power system to charge the battery. If many EVs are connected during a short time, power quality problems can occur such as voltage sag, voltage unbalance and harmonics which are generated from power electronics devices. Therefore, when EVs are charged, it is necessary to analyze the effect of power quality on the distribution system, because EVs will gradually replace gasoline vehicles, and the number of EVs will be increased. In this paper, a battery for EVs and a PWM converter are modeled using an ElectroMagnetic Transient Program (EMTP). The voltage sag and unbalance are evaluated when EVs are connected to the distribution system of the Korea Electric Power Corporation (KEPCO). The simulation results are compared with IEEE standards.

• 대한의용생체공학회:의공학회지
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• 제45권1호
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• pp.20-25
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• 2024

Extracellular vesicles (EVs) are nano-sized lipid bilayer vesicles released by cells. EVs act as messengers for cell-to-cell communication. Inside, it contains various substances that show biological activity, such as proteins, lipids, nucleic acids, and metabolites. The study of EVs extracted from terrestrial organisms and stem cells on inflammatory environments and tissue regeneration have been actively conducted. However, marine organisms-derived EVs are limited. Therefore, we have extracted EVs from sea urchins belonging to the Echinoderm group with their excellent regenerative ability. First, we extracted extracellular matrix (ECM) from sea urchin gonads treated with hypotonic buffer, followed by collagenase treatment, and filtration to collect ECM-bounded EVs. The size of sea urchin gonad-derived EVs (UGEVs) is about 20-100 nm and has a round shape. The protein content was higher after EVs burst than before, which is evidence that proteins are contained inside. In addition, proteins of various sizes are distributed inside. PKH-26 was combined with UGEVs, which means that UGEVs have a lipid membrane. PHK-26-labeled UGEVs were successfully uptaken by cells. UGEVs can be confirmed to have the same characteristics as traditional EVs. Finally, it was confirmed that Schwann cells were not toxic by increasing proliferation after treatment.

• 한국수소및신에너지학회논문집
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• 제28권1호
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• pp.56-62
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• 2017

Although most electricity production contributes to air pollution, the vehicle organizations and environmental agency categorizes all EVs as zero-emission vehicles because they produce no direct exhaust or emissions. Currently available EVs have a shorter range per charge than most conventional vehicles have per tank of gas. EVs manufacturers typically target a range of 160 km over on a fully charged battery. The energy efficiency and driving range of EVs varies substantially based on driving conditions and driving habits. Extreme outside temperatures tend to reduce range, because more energy must be used to heat or cool the cabin. High driving speeds reduce range because of the energy required to overcome increased drag. Compared with gradual acceleration, rapid acceleration reduces range. Additional devices significant inclines also reduces range. Based on these driving modes and climate conditions, this paper discusses the performance characteristics of EVs on energy efficiency and driving range. Test vehicles were divided by low / high-speed EVs. The difference of test vehicles are on the vehicle speed and size. Low-speed EVs is a denomination for battery EVs that are legally limited to roads with posted speed limits as high as 72 km/h depending on the particular laws, usually are built to have a top speed of 60 km/h, and have a maximum loaded weight of 1,400 kg. Each vehicle test was performed according to the driving modes and test temperature ($-25^{\circ}C{\sim}35^{\circ}C$). It has a great influence on fuel efficiency amd driving distance according to test temperature conditions.

• BMB Reports
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• 제53권2호
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• pp.118-123
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• 2020

Cardiac regeneration with adult stem-cell (ASC) therapy is a promising field to address advanced cardiovascular diseases. In addition, extracellular vesicles (EVs) from ASCs have been implicated in acting as paracrine factors to improve cardiac functions in ASC therapy. In our work, we isolated human cardiac mesenchymal stromal cells (h-CMSCs) by means of three-dimensional organ culture (3D culture) during ex vivo expansion of cardiac tissue, to compare the functional efficacy with human bone-marrow derived mesenchymal stem cells (h-BM-MSCs), one of the actively studied ASCs. We characterized the h-CMSCs as CD90^low, c-kit^negative, CD105^positive phenotype and these cells express NANOG, SOX2, and GATA4. To identify the more effective type of EVs for angiogenesis among the different sources of ASCs, we isolated EVs which were derived from CMSCs with either normoxic or hypoxic condition and BM-MSCs. Our in vitro tube-formation results demonstrated that the angiogenic effects of EVs from hypoxia-treated CMSCs (CMSC-Hpx EVs) were greater than the well-known effects of EVs from BM-MSCs (BM-MSC EVs), and these were even comparable to human vascular endothelial growth factor (hVEGF), a potent angiogenic factor. Therefore, we present here that CD90^lowc-kit^negativeCD105^positive CMSCs under hypoxic conditions secrete functionally superior EVs for in vitro angiogenesis. Our findings will allow more insights on understanding myocardial repair.

• Molecules and Cells
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• 제45권6호
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• pp.376-387
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• 2022

Extracellular vesicles (EVs) play an essential role in the communication between cells and the tumor microenvironment. However, the effect of tumor-derived EVs on the growth and metastasis of lung adenocarcinoma (LUAD) remains to be explored. This study aimed to elucidate the role of miR-153-3p-EVs in the invasion and migration capabilities of LUAD cells and explore its mechanism through in vivo and in vitro experiments. We found that miR-153-3p was specifically and highly expressed in LUAD and its secreted EVs. Furthermore, the expression of BANCR was negatively regulated by miR-153-3p and identified as a target gene of miR-153-3p using luciferase reporter assays. Through further investigation, we found that the downregulation of BANCR activates the PI3K/AKT pathway and accelerates the process of epithelial-mesenchymal transition (EMT), which ultimately leads to the aggravation of LUAD. The orthotopic xenograft mouse model was established to illustrate the effect of miR-153-3p-EVs on LUAD. Animal studies showed that miR-153-3p-EVs accelerated tumor growth in mice. Besides, we found that miR-153-3p-EVs could damage the respiratory ability of mice and produce a mass of inflammatory cells around the lung tissue of mice. Nevertheless, antagomir-153-3p treatment could inhibit the deterioration of respiratory function and inhibit the growth of lung tumors in mice. In conclusion, our study reveals the potential molecular mechanism of miR-153-3p-EVs in the development of LUAD and provides a potential strategy for the treatment of LUAD.

• 대한수의학회지
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• 제63권4호
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• pp.40.1-40.7
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• 2023

To optimize the most efficient method for porcine in vitro maturation (IVM), we compared the effects of supplementing extracellular vesicles (EVs) derived from porcine follicular fluid (pFF). The cumulus oocyte complexes were grouped into 4 groups with different supplementations as following: pFF (G1), pFF-depleted EVs (G2), EVs (G3) and control (G4) groups. After IVM with different supplementations, maturation rates and the developmental competences of porcine oocytes and blastocyst development were investigated. Additionally, glutathione (GSH) and reactive oxygen species (ROS) levels were measured in mature oocytes. The EVs were isolated and characterized with cryo-TEM and nanoparticle tracking analysis. The pFF significantly affected the maturation rate, whereas the presence of EVs did not show notable difference in the maturation rates. Although there were numerical increases in the measured parameters in EV and pFF-depleted EVs groups, no significant differences were observed between them. The EV group showed similar oocyte maturation rate for both positive and negative control groups. The GSH was not different among the groups, but ROS levels were significantly lower in pFF-supplemented group when compared with other groups with the highest level in the control group. G2 group wasn't significantly different G1 and G3 group. G3 group wasn't significantly different from G2 and G4 group. This suggests that EVs in IVM medium which probably effected partially to protect against oxidative stress and potentially enhance the quality of oocytes. This study indicates that the EVs in pFF play a significant role in improving the efficiency of oocyte maturation in porcine.

• 조명전기설비학회논문지
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• 제29권1호
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• pp.37-46
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• 2015

In order to charge EVs, they have to be connected to distribution system. Therefore, if unprecedented numbers of EVs are connected to power systems, it could result in deterioration of power quality, overload, and other system problems. In this paper, the effects of voltage sag on the distribution system due to the connection of EVs is evaluated by considering related field data of Republic of Korea such as the number of gasoline-fueled vehicles, seasonal load of power system and the monthly and daily real-time traffic volume. The distribution system and EVs are modeled using the Electro Magnetic Transients Program (EMTP).

• KEPCO Journal on Electric Power and Energy
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• 제6권3호
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• pp.315-319
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• 2020

The modern transportation and mobility sector is expected to encounter high penetration of Electric Vehicles (EVs) because EVs contribute to reducing the harmful emissions from fossil fuel-powered vehicles. With the prospective growth of EVs, sufficient and convenient facilities for fast charging are crucial toward satisfying the EVs' quick charging demand during their trip. Therefore, the Fast Electric Vehicle Charging Stations (FECS) will be a similar role to gas stations. In this paper, we study a charging scheduling problem for the FECS with solar photovoltaic (PV) and an Energy Storage System (ESS). We formulate an optimization problem that minimizes the operational costs of FECS. There are two cost and one revenue terms that are buying cost from main grid power, ESS degradation cost, and revenue from the charging fee of the EVs. Simulation results show that the proposed scheduling algorithm reduces the daily operational cost by effectively using solar PV and ESS.

• Molecules and Cells
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• 제45권11호
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• pp.771-780
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• 2022

The field of extracellular vesicles (EVs) has expanded tremendously over the last decade. The role of cell-to-cell communication in neighboring or distant cells has been increasingly ascribed to EVs generated by various cells. Initially, EVs were thought to a means of cellular debris or disposal system of unwanted cellular materials that provided an alternative to autolysis in lysosomes. Intercellular exchange of information has been considered to be achieved by well-known systems such as hormones, cytokines, and nervous networks. However, most research in this field has searched for and found evidence to support paracrine or endocrine roles of EV, which inevitably leads to a new concept that EVs are synthesized to achieve their paracrine or endocrine purposes. Here, we attempted to verify the endocrine role of EV production and their contents, such as RNAs and bioactive proteins, from the regulation of biogenesis, secretion, and action mechanisms while discussing the current technical limitations. It will also be important to discuss how blood EV concentrations are regulated as if EVs are humoral endocrine machinery.