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초고성능액체크로마토그래피-텐덤질량분석법에 의한 혈청 중스핑고신과 스핑고신-1-포스페이트의 동시 분석
나승훈(Seonghoon Na),윤혜란(Hye-Ran Yoon) 대한약학회 2021 약학회지 Vol.65 No.1
Sphingosine (SPH) and sphingosine-1-phosphate (S1P) are emerging as key players in asthma metabolism and in numerous cellular inflammation processes. To identify potential biomarkers of asthma and inflammatory therapeutics, it is essential to determine their levels. Herein, we developed a rapid and sensitive UHPLC-MS/MS method to simultaneously quantify SPH and S1P in human serum using C17-SPH and C17-S1P as internal standards. After methanol precipitation of serum proteins, the supernatants were analyzed by MS/MS performed in the positive ion mode by multiple reaction monitoring. UHPLC analysis (C18 column) was performed using two mobile phase systems (water containing 0.1% formic acid, and 85% acetonitrile containing 0.1% formic acid) within 5 min of the short run. The calibration curves were linear in the range of 0.002-1.5 µg/mL for S1P and SPH with an R 2 greater than 0.9999. The LOD and LOQ were 0.0002 and 0.0004 µg/mL for S1P, and 0.0005 and 0.001 µg/mL for SPH, respectively. The accuracy and precision of the method were in the range of 89.8-100.7% (RSD, 1.5-2.8%) for both SPH and S1P species. We were able to quantify both molecules in serum from healthy and asthmatic patients. These results suggest that SPH and S1P are promising potential biomarkers, and also contribute to the basic data for the construction of an omics-based platform for preventive index prior to asthma diagnosis.
초고성능액체크로마토그래피-탠덤매스에 의한 혈장과 담즙 중 콜릭산의 정량 분석에 관한 연구
나승훈(Seonghoon Na),윤혜란(Hye-Ran Yoon) 대한약학회 2019 약학회지 Vol.63 No.6
Bile acids are increasingly appreciated as bioactive molecules and important end products of cholesterol metabolism. While they have been identified as key factors in lipid emulsification and absorption due to their detergent properties. bile acids have also been shown to act as signaling molecules and intermediates between the host and the gut microbiota. To investigate bile acid functions in humans, an advanced platform for high throughput analysis is essential. Herein, we developed the analytical method of cholic acids following simple one step protein precipitation from biological sample by UPLC-MS/MS. MRM ions was m/z=407.2 for cholic acid. The R2 of calibration curves provided 0.9995 in the calibration range of 0.005~5 μg/mL. The quantification system was validated with excellent sensitivity that allows quantitative targeted analyses of bile acids. The LOD (0.001 μg/mL), LOQ (0.005 μg/mL), recoveries (96.8~101.3%± 2.7~4.0%) on intra-day assay, and (98.4~111.0%±2.3~3.4%) on inter-day assay achieved resonable validated data for bile acids analyses. The developed method was applied for drawing plasma and bile acid profile in both normal and disease status. Our study is characterized by rapid and simple sample preparation as well as successful application to plasma and bile. These results could be usable for routine diagnostic monitoring of bile acids on human biofluids.
Cu를 포함한 CrCoFeMnNi 용접재료를 적용한 GTA 용접부의 PWHT 온도의 영향
유성훈(Seonghoon Yoo),이유나(Yoona Lee),나영상(Youngsang Na),김형섭(Hyoungseop Kim),강남현(Namhyun Kang) 대한용접·접합학회 2021 대한용접학회 특별강연 및 학술발표대회 개요집 Vol.2021 No.11
최근 가혹한 환경에서 적용되는 구조용 재료의 수요가 증가함에 따라 재료의 고기능화가 요구되고 있다. 현재 극저온 환경에서 적용되는 구조용 재료는 FCC 결정구조를 갖는 오스테나이트계 스테인레스 강을 주로 사용하나, 이를 용접 재료를 사용할 경우 고온균열 및 입계 예민화 현상이 발생하게 된다. 따라서 이러한 대안으로 현재 고엔트로피 합금 (High Entropy Alloy, HEA)이 개발되었으며, 이를 상온 및 극저온용 구조재료로 적용하기 위한 연구가 활발히 진행되고 있다. 고엔트로피 합금이란, 여러 원소를 혼합하여 발생하는 배열 엔트로피 증가로 인한 hign-entropy effect, sluggish diffusion, lattice distortion, cocktail effect의 4가지 core 현상을 기반으로 기계적 특성이 우수한 합금이다. 특히 기존의 HEA 대비 가격 경쟁력 및 기계적 성질이 우수한 Fe-base 중엔트로피 합금(Medium Entropy Alloy, MEA)이 최근 개발되고 있으며, 이를 구조용 재료로 적용하기 위해 용접 기술을 최적화하는 연구가 활발히 진행하고 있다. 따라서 본 연구에서는 Fe-rich MEA에 적합한 HEA 용접재료 개발을 목표로 진행하였으며, 용접재료는 결정립 미세화, 석출강화 및 제 2상 FCC를 형성시키는 Cu를 소량 첨가하기 위해 FCC계 HEA인 Cantor alloy(CoCrFeMnNi)에 Cu를 코팅하여 (CoCrFeMnNi)99Cu1 용접재료를 개발하였으며, 이를 Fe-rich MEA 모재에 적용하였다. 또한 구조용 재료에 필요한 용접후열처리(Post Weld Heat Treatment, PWHT) 효과를 확인하기 위해 PWHT를 진행하였다. 본 연구에 사용된 모재는 1.5mm 두께의 Rolled Fe-rich MEA를 사용하였으며, V-groove에 언급한 (CoCrFeMnNi)99Cu1 용접재료를 적용하여 GTAW를 실시하였다. PWHT는 700, 800, 900℃에서 1시간 진행하였으며, As-welded 조건과 PWHT 온도에 따른 기계적 성질 및 미세조직 차이에 대해 검토하였으며, 인장 파단 위치에 영향을 미치는 인자에 대해 미세조직학적으로 고찰하였다.
급성 결핵성수막염의 양상을 보이는 속립성 결핵에 동반된 신경 베쳇증후군
은성훈(Seonghoon Eun),김영덕(Young Duck Kim),이대용(Dae Yong Yi),이나미(Na Mi Lee),윤신원(Sin Weon Yun),채수안(Soo Ahn Chae),임인석(InSeok Lim ),최응상(Eung Sang Choi) 대한소아신경학회 2016 대한소아신경학회지 Vol.24 No.1
A 14-year-old girl diagnosed with Behçet's disease 15 months previously presented at the emergency department with severe headache, fever, and vomiting. Chest radiographic and computed tomography findings were consistent with miliary tuberculosis, and pleocytosis and increased protein levels were found on examination of cerebrospinal fluid (CSF). Tuberculous meningitis associated with miliary pulmonary tuberculosis was suspected, and a four-drug regimen for tuberculosis plus intravenous dexamethasone was initiated. However, negative results of real-time polymerase chain reaction and CSF cultures led us to reconsider our initial diagnosis. On brain magnetic resonance imaging, the results supported neuro-Behçet's syndrome rather than tuberculous meningitis. However, it is unclear how miliary tuberculosis complicated neuro-Behçet's syndrome because the patient had no history of tuberculosis or contact with patients with tuberculosis, and had not used any immunosuppressive agents such as anti-tumor necrosis factor-alpha drugs. This is a very rare case of neuro-Behçet's syndrome associated with miliary tuberculosis. More commonly, cases of neuro-Behçet's syndrome presenting with features mimicking acute tuberculous meningitis have been reported. Neuro- Behçet's syndrome should be considered in patients with a history of Behçet's disease presenting with signs of meningeal irritation.