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Yeonkyeong Lee,Harry Jung,Jong-Ho Kim,Jong-Hee Sohn 한국실험동물학회 2021 한국실험동물학회 학술발표대회 논문집 Vol.2021 No.7
Introduction: Postoperative cognitive dysfunction (POCD) following anesthesia and surgery is a common and severe complication, especially in elderly patient. Several previous studies have suggested that anesthesia and surgery may increase the Alzheimer’s disease (AD) risk, although it is unknown whether anesthesia or surgery has more effects on cognition. Thus, we investigated the differences of cognition and neuropathology whether anesthesia only or surgery/anesthesia can have different effects in AD mouse model. Methods: The 5-month-old ApoE4 KI male mouse were randomly assigned to anesthesia/surgery group or anesthesia only group. We performed abdominal surgery under isoflurane anesthesia (2.5%) or only anesthesia during two hours. Morris water maze (MWM)and Y maze tests were conducted 2 days before and 2, 4, 7 days after anesthesia and surgery. The mean escape latencies and spontaneous alternation percentage were the major outcome. Neuron apoptosis in hippocampal sections was evaluated using the terminal d-UTP nick-end labeling (TUNEL) assay. Amyloid beta (Ab) level were assessed by quantitative immunohistochemistry (IHC). Results: The anesthesia/surgery group exhibited increased mean escape latencies of MWM at postoperative 2 day, whereas anesthesia only group exhibited such increases at postoperative 4 day. However, performance on a Y-maze test did not differ. More TUNEL-positive neurons were evident in the hippocampal CA3 region of anesthesia only group at postoperative days 2 and 4, but not at day 7 (P < 0.05). Also, IHC revealed significantly elevated Aβ deposition in the hippocampal CA3 and dentate gyrus region of anesthesia only group at postoperative days 2, 4 and 7 (P < 0.05). Conclusions: Isoflurane anesthesia induced pathological hippocampal changes in ApoE4 KI mice, but not in isoflurane anesthesia/surgery group. We suggest that isoflurane anesthesia itself has a more detrimental effect on cognition and neuropathology in AD mouse models than surgery.
Yeonkyeong Lee,Sooyeon Kim,Jihoon Wang,Wonmo Sung 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.88 No.-
This study investigates enhanced oil recovery (EOR) and CO2 storage efficiencies during low-salinitycarbonate waterflooding (LSCWF) in carbonate reservoirs containing “acid” formation water. In order toidentify the detailed geochemical reactions for acidic condition during LSCWF, simulational analysis wasperformed with “CMG-GEM”. After core-scaled model was constructed through history-matchingprocesses based on the coreflooding experimental results, primary mechanisms during LSCWF wereanalyzed for various levels of injection water salinity. From the results of this study, CO2 dissolved ininjected carbonate water yielded CaCO3 precipitation in acidic reservoirs, decreasing permeabilitysignificantly compared to in neutral reservoirs. In terms of wettability alteration and oil swelling by CO2mass transfer, their effects were almost similar regardless of the salinity for both acid and neutralreservoirs. In the aspects of EOR and CO2 storage efficiencies, they strongly depend on the salinity for bothacidic and neutral conditions. In the results of EOR–CO2 storage relationship, enhanced oil was smaller inacidic condition, while CO2 storage efficiency was not greatly related to acidity of the reservoir. Thefindings of this study can help for better understanding of smart water injection design into acidcarbonate reservoir for the optimal EOR and CO2 storage efficiencies.
탄산염암 저류층에 저염수주입공법과 폴리머공법의 복합 적용에 따른 오일 생산량 평가
이연경(Yeonkyeong Lee),김수연(Sooyeon Kim),이원석(Wonsuk Lee),장영호(Youngho Jang),성원모(Wonmo Sung) 한국가스학회 2018 한국가스학회지 Vol.22 No.5
저염수 기반 폴리머공법은 기존의 폴리머공법과 저염수주입공법의 시너지 효과를 통해 오일회수율을 더욱 증진시킬 수 있는 기술로서, 공법의 효율성을 극대화하기 위해서는 폴리머의 특성을 고려한 저염수 설계가 필수적이다. 이에 본 연구에서는 탄산염암 오일 저류층에 저염수 기반 폴리머공법 적용 시, 주입수의 pH와 주입수 내 PDI(Potential Determining Ion) 이온 중 SO₄<SUP>2-</SUP> 이온이 오일 생산량에 미치는 영향을 규명하고자 하였다. 우선, 주입수의 pH와 주입수 내 SO₄<SUP>2-</SUP>의 농도에 따른 폴리머 분자의 안정성 및 흡착 현상을 분석하였다. 그 결과, 주입수의 pH와 주입수 내 SO₄<SUP>2-</SUP>의 농도에 상관없이, 주입수 내 SO₄<SUP>2-</SUP>가 함유되어 있는 경우 폴리머 용액의 안정성이 확보되었다. 그러나, 폴리머 용액의 정체 현상 분석 결과, 주입수의 pH가 중성인 7일 때에는 SO₄<SUP>2-</SUP> 이온이 폴리머의 흡착을 방해하여 SO₄<SUP>2-</SUP>의 농도가 높을수록 폴리머 흡착층의 두께가 더 얇은 것으로 나타난 반면에, 주입수가 pH 4로 산성인 경우에는 폴리머 용액을 주입함에 따라 폴리머의 흡착량이 증가하여 폴리머 용액의 유동성이 크게 낮아졌다. 다음으로, 저염수 효과에 의한 습윤도 변환을 살펴본 결과, 주입수가 중성일 때에는 SO₄<SUP>2-</SUP>의 농도가 높을수록 탄산염암 표면에 흡착되어 있던 오일의 탈착이 증가하여 암석의 습윤도가 친유성에서 친수성으로 크게 변환되었다. 반면에, 주입수가 산성일 때에는 용해와 폴리머 흡착의 복합적 작용으로 인해 전체 코어 시스템의 습윤도는 중성일 때에 비해 비교적 덜 변환되는 것으로 나타났다. 이에 따라 SO₄<SUP>2-</SUP> 농도가 높은 중성의 저염수 기반 폴리머 용액을 주입할 경우 오일 생산량은 저염수주입공법에 비해 최대 12.3% 증진되어 보다 양호한 EOR(Enhanced Oil Recovery) 효과를 얻을 수 있는 것으로 평가되었다. Low-salinity water based polymerflooding (LSPF) is one of promising enhanced oil recovery (EOR) method that has the synergetic effect of combining polymer injection method and low-salinity water injection method. In order to maximize EOR efficiency, it is essential to design low-salinity water appropriately considering the properties of polymer. In this aspect, the main purpose of this study is to investigate the effect of pH and SO₄<SUP>2-</SUP><SUP></SUP> ion which one of PDI (Potential Determining Ion) on oil production when applying LSPF to carbonate oil reservoir. First, the stability and adsorption of polymer molecule were analyzed in different pH of injection water and SO₄<SUP>2-</SUP> concentration in injection water. As a result, regardless of pH and SO42- concentration, when SO₄<SUP>2-</SUP> ion was contained in injection water, the stability of polymer solution was obtained. However, from the result of polymer retention analysis, in neutral state of injection water, since SO₄<SUP>2-</SUP> interfered the adsorption of polymer, the adsorption thickness of polymer was thinner as SO₄<SUP>2-</SUP> concentration was higher. On the other hand, when injection water was acidic as pH 4, the amount of polymer adsorption increased with the injection of polymer solution, so the mobility of polymer solution was greatly lowered. From the results of wettability alteration due to low-salinity water effect, in the case of neutral injection water injected, as SO₄<SUP>2-</SUP> concentration was increased, more oil which attached on rock surface was detached, altering wettability from oil-wet to water-wet. On the other hand, in acidic condition, due to complex effect of rock dissolution and polymer adsorption, wettability of the entire core system was less altered relatively to neutral condition. Therefore, it was evaluated that better EOR efficiency was obtained when injecting low-salinity water based polymer solution containing high concentration of SO42- with neutral condition, enhancing the oil production up to 12.3% compared to low-salinity water injection method.