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Ra-Yeong Choi,Ju Ri Ham,Jiyoung Yeo,Jae-Seoun Hur,Seok-Kyu Park,Myung-Joo Kim,Mi-Kyung Lee 한국식품영양과학회 2017 Preventive Nutrition and Food Science Vol.22 No.4
Thamnolia vermicularis (TV) is an edible lichen that is prevalent in the alpine zone of East Asia. This study evaluated the feasibility of using TV acetone extracts as a functional food based on experiments using cell line and obese mice. The cellular triglyceride levels and Oil red O staining of 3T3-L1 cells indicated that TV extracts (5 and 10 μg/mL) dose-dependently suppressed adipocyte differentiation and lipid accumulation compared with the control. The TV extract (0.4%, w/w) in a high-fat diet (HFD) was supplemented to C57BL/6N mice for 12 weeks, and TV extract supplement significantly reduced visceral fat mass and body weight compared with HFD feeding alone. The TV extract also induced significant decreases in serum and hepatic lipids, whereas it increased the serum high-density lipoproteins-cholesterol/total cholesterol ratio and fecal lipids levels. Moreover, the TV extract led to significantly lower homeostasis model assessment of insulin resistance in diet-induced obese mice. Taken together, these results suggest that the TV extract may have anti- obesity effects, including lipid-lowering, and it is a natural resource with the potential for use in obesity management.
GM-CSF Enhances Mobilization of Bone Marrow Mesenchymal Stem Cells via a CXCR4-Medicated Mechanism
Jiyoung Kim,Na Kyeong Kim,SO-RA PARK,Byung Hyune Choi 한국조직공학과 재생의학회 2019 조직공학과 재생의학 Vol.16 No.1
BACKGROUND: This study was conducted to investigate the effect of granulocyte–macrophage colony-stimulating factor (GM-CSF) on the mobilization of mesenchymal stem cells (MSCs) from the bone marrow (BM) into the peripheral blood (PB) in rats. METHODS: GM-CSF was administered subcutaneously to rats at 50 lg/kg body weight for 5 consecutive days. The BM and PB of rats were collected at 1, 3, and 5 days during the administration for analysis. RESULTS: Upon GM-CSF administration, the number of mononuclear cells increased rapidly at day 1 both in the BM and PB. This number decreased gradually over time in the BM to below the initial amount by day 5, but was maintained at a high level in the PB until day 5. The colony-forming unit–fibroblasts were increased in the PB by 10.3-fold at day 5 of GM-CSF administration, but decreased in the BM. Compared to GM-CSF, granulocyte-colony stimulating factor (G-CSF) stimulated lower levels of MSC mobilization from the BM to the PB. Immunohistochemical analysis revealed that GMCSF induced a hypoxic and proteolytic microenvironment and increased C-X-C chemokine receptor type 4 (CXCR4) expression in the BM. GM-CSF added to BM MSCs in vitro dose-dependently increased CXCR4 expression and cell migration. G-CSF and stromal cell derived factor-1 (SDF-1) showed similar results in these in vitro assays. Know-down of CXCR4 expression with siRNA significantly abolished GM-CSF- and G-CSF-induced MSC migration in vitro, indicating the involvement of the SDF-1–CXCR4 interaction in the mechanism. CONCLUSION: These results suggest that GM-CSF is a useful tool for mobilizing BM MSCs into the PB.
NH₃/H₂O 혼합냉매를 사용한 압축/흡수식 히트펌프 시스템의 흡수기 최적화에 관한 실험적 연구
김지영(Jiyoung Kim),김민성(Minsung Kim),백영진(Young-Jin Baik),박성룡(Seong-Ryong Park),장기창(Ki-Chang Chang),나호상(Ho-Sang Ra),김용찬(Yongchan Kim) 대한기계학회 2011 大韓機械學會論文集B Vol.35 No.3
본 연구는 암모니아/물 혼합냉매를 이용한 압축/흡수식하이브리드 히트펌프 개발에 관한 연구이다. 히트펌프 사이클은 증기압축식과흡수식을 혼합한 개념으로 이단압축기, 흡수기, 재생기, 과열냉각기, 용액열교환기(SHX), 용액펌프, 정류기, 기액분리기 등으로 구성되어 있다. 압축/흡수식 히트펌프는 상변화열교환과정에서 높은 온도구배를 이용하여 90℃ 이상의 고온을 제조하기 위한 목적으로 고안되었다. 특히 흡수기에서의 응축과정은 비열변화로 인하여 온도변화에 비선형성이 뚜렷한데, 시스템 성능 최적화를 위하여는 흡수기의 설계가 중요하다. 본 연구에서는 다수의 판형열교환기로 흡수기를 구성하였는데 열교환기의 용량, 형태, 배치에 따른 성능특성을 실험적으로 관찰하였다. This research aims todevelopa compression/absorption hybrid heat pump system using an NH₃/H₂O as working fluid.The heatpump cycle is based on a combination of compression and absorption cycles. The cycle consists of two-stage compressors, absorbers, a desorber, a desuperheater, solution heat exchangers, a solution pump, a rectifier, and a liquid/vapor separator. The compression/absorption hybrid heat pump was designed to produce hot water above 90℃ using high-temperature glide during a two-phase heat transfer. Distinct characteristics of the nonlinear temperature profile should be considered to maximize the performance of the absorber. In this study, the performance of the absorber was investigated depending on the capacity, shape, and arrangementof the plate heat exchangers with regard tothe concentration and distribution at the inlet of the absorber.
천연혼합냉매를 이용한 압축/흡수식 고온히트펌프의 실험적 연구
김지영(Jiyoung Kim),김민성(Minsung Kim),백영진(Young Jin Baik),박성룡(Seong Ryong Park),장기창(Ki Chang Chang),나호상(Ho Sang Ra),김용찬(Youngchan Kim) 대한기계학회 2011 대한기계학회 춘추학술대회 Vol.2011 No.5
본 연구는 천연냉매를 적용한 압축/흡수식 고온히트펌프의 개발에 관한 것이다. 압축/흡수 히트펌프는 기존의 증기 압축 히트 펌프에 비해 넓은 온도범위 및 고온, 유연한 작동 범위, 용량 제어 등 매력적인 장점을 제공한다. 주요 연구 목표는 90℃ 이상의 고온수 생산 및 용량 10㎾ 급의 고온히트펌프 개발에 있으며 프로타입 하이브리드 시스템은 이단압축기, 업소버, 디소버, 과열냉각기, 용액 열교환기, 용액펌프, 정류기, 기액분리기 등으로 구성되어 있다. 시스템 운전 특성은 혼합냉매의의 구성에 따라 변화되며 본 연구에서는 압축/흡수 고온히트펌프의 작동 특성을 실험적으로 혼합냉매의의 조성을 변화시키면서 관찰하였고 실험 결과를 통해 다양한 시스템의 특성을 예측하는 연구를 수행하였다. This research is about developing a compression/absorption high temperature hybrid heat pump system using natural mixtures. The compression/absorption heat pump provides a number of attractive advantages in comparison with conventional vapor compression heat pump. Advantages large temperature glide, temperature lift, flexible operating range, capacity control, etc. This study main purpose is to produce hot water over 90 ℃ and heating capacity 10㎾. The prototype hybrid heat pump cycle consist of two-stage compressor absorber, desorber, de-superheat, solution heat exchanger, solution pump, rectifier, liquid/vapor separator, etc. Especially system operating characteristic are due to changes in the ammonia concentration. In this study, operating characteristic of compression/absorption heat pump was experimentally observed by ammonia concentration in solution. And the experimental results were predicting various system characteristics.
산업용 압축/흡수식 하이브리드 히트펌프 시스템의 운전특성에 관한 실험적 연구
김지영(Jiyoung Kim),박성룡(Seong-Ryong Park),김민성(Minsung Kim),백영진(Young-Jin Baik),장기창(Ki-Chang Chang),라호상(Ho-Sang Ra),김용찬(Yongchan Kim) 대한기계학회 2012 대한기계학회 춘추학술대회 Vol.2012 No.11
In industrial process plants, there is an large amount of waste heat that will not be utilized because the temperature is too low. The purpose of this study is the development of a heat pump system that can be upgraded post-processed waste heat into 90℃ of reheated water using low temperature industrial waste heat. This study, heat pump system is based on a combination of compression and absorption cycles. This compression/absorption hybrid heat pump provides a number of advantages over conventional vapor compression heat pumps. These include a large temperature glide, an improved temperature lift, a flexible operating range, and capacity control. In this study, the effect of the operation characteristics of the compression/absorption hybrid heat pump was experimentally observed.
NH₃/H₂O 혼합냉매를 사용한 압축/흡수식 히트펌프 시스템의 흡수기 최적화에 관한 실험적 연구
김지영(Jiyoung Kim),김민성(Minsung Kim),백영진(Young-Jin Baik),박성룡(Seong-Ryong Park),장기창(Ki-Chang Chang),나호상(Ho-Sang Ra),김용찬(Yongchan Kim) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.5
본 연구는 암모니아/물 혼합냉매를 이용한 압축/흡수식 하이브리드 히트펌프 개발에 관한 연구이다. 히트펌프 사이클은 중기압축식과 흡수식을 혼합한 개념으로 이단압축기, 흡수기, 재생기, 과열냉각기, 용액열교환기, 용액펌프, 정류기, 기액분리기 등으로 구성되어 있다. 압축/흡수식 히트펌프는 상변화 열교환과정에서 높은 온도구배를 이용하여 90℃ 이상의 고온을 제조하기 위한 목적으로 고안되었다. 특히 흡수기에서의 응축과정은 비열변화로 인하여 온도변화에 비선형성이 뚜렷한데, 시스템 성능 최적화를 위하여는 흡수기의 설계가 중요하다. 본 연구에서는 다수의 판형열교환기로 흡수기를 구성하였는데 열교환기의 용량, 형태, 배치에 따른 성능특성을 실험적으로 관찰하였다. This research is about developing a compression-absorption hybrid heat pump system using NH₃/H₂O Mixtures. The heat pump cycle is based on combination of compression and absorption cycle. The cycle consist of two-stage compressors, absorbers, a desorber, a desuperheater, solution heat exchangers, a solution pump, a rectifier, and a liquid/vapor separator. The compression/absorption hybrid heat pump was designed to produce hot water over 90℃ using high temperature glide during two-phase heat transfer. Especially, distinct characteristics of a non-linear temperature profile should be considered for absorber design to maximize system performance. In this study, performance of the absorber was observed by the capacity, shape, and arrangement of plate heat exchangers with regard to concentration and distribution at the inlet of the absorber.
천연혼합냉매를 이용한 압축/흡수식 고온히트펌프의 실험적 연구
김지영(Jiyoung Kim),박성룡(Seong-Ryong Park),백영진(Young-Jin Baik),장기창(Ki-Chang Chang),나호상(Ho Sang Ra),김민성(Minsung Kim),김용찬(Yongchan Kim) 대한기계학회 2011 大韓機械學會論文集B Vol.35 No.12
본 연구에서는 천연냉매를 적용한 압축/흡수식 하이브리드 고온제조 히트펌프를 실험적으로 연구한 결과를 제시하였다. 압축/흡수식 히트펌프는 기존의 증기압축 히트펌프에 비해 고온영역을 포함한 넓은 생산온도범위, 높은 승온기능, 다양한 용량 제어방법 등 여러가지 장점을 가지고 있다. 제작된 하이브리드 히트펌프는 현재 실제 산업현장에 적용하기 이전의 초기 시제품 단계로 실험실에 설치하여 운전하였으며, 주요 구성부품으로는 이단압축기, 흡수기, 재생기, 과열냉각기, 용액 열교환기, 용액펌프, 기액분리기/정류기 등이다. 성능실험에서 50℃의 열원을 고온 및 저온열원으로 사용한 결과 90℃ 이상의 고온수 토출과 10 ㎾급의 난방용량을 얻을 수 있었다. 혼합냉매의 성분비 변화에 따른 압축기/펌프 유량의 순환비 변화 및 다양한 성능변화를 실험적으로 관찰하였으며, 시스템의 효율과 용량에 있어 최적 성분비가 존재함을 확인하였다. This research concerns the development of a compression/absorption high-temperature hybrid heat pump that uses a natural refrigerant mixture. Heat pumps based on the compression/absorption cycle offer various advantages over conventional heat pumps based on the vapor compression cycle, such as large temperature glide, temperature lift, flexible operating range, and capacity control. In this study, a lab-scale prototype hybrid heat pump was constructed with a two-stage compressor, absorber, desorber, desuperheater, solution heat exchanger, solution pump, liquid/vapor separator, and rectifier as the main components. The hybrid heat pump system operated at 10-㎾-class heating capacity producing hot water whose temperature was more than 90°C when the heat source and sink temperatures were 50℃. Experiments with various NH₃/H₂O mass fractions and compressor/pump circulation ratios were performed on the system. From the study, the system performance was optimized at a specific NH₃ concentration.