• Title/Summary/Keyword: ACN

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Updates in postural tachycardia syndrome

  • Moon, Jangsup
    • Annals of Clinical Neurophysiology
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    • v.23 no.1
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    • pp.1-6
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    • 2021
  • Postural tachycardia syndrome (POTS) is the most common form of orthostatic intolerance in young people. However, it is still considered an underrecognized disorder and so deserves more attention from clinicians. This review covers the diagnostic challenges, correlations between the symptoms, evidence of autoimmune involvement in the pathogenesis, and treatment strategies in POTS.

Lithium Bis(oxalate)borate as an Electrolyte Salt for Supercapacitors in Elevated Temperature Applications

  • Madzvamuse, Alfred;Hamenu, Louis;Mohammed, Latifatu;Bon, Chris Yeajoon;Kim, Sang Jun;Park, Jeong Ho;Ko, Jang Myoun
    • Journal of Electrochemical Science and Technology
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    • v.8 no.4
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    • pp.314-322
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    • 2017
  • The electrolyte plays one of the most significant roles in the performance of electrochemical supercapacitors. Most liquid organic electrolytes used commercially have temperature and potential range constraints, which limit the possible energy and power output of the supercapacitor. The effect of elevated temperature on a lithium bis(oxalate)borate(LiBOB) salt-based electrolyte was evaluated in a symmetric supercapacitor assembled with activated carbon electrodes and different electrolyte blends of acetonitrile(ACN) and propylene carbonate(PC). The electrochemical properties were investigated using linear sweep voltammetry, cyclic voltammetry, galvanostatic charge-discharge cycles, and electrochemical impedance spectroscopy. In particular, it was shown that LiBOB is stable at an operational temperature of $80^{\circ}C$, and that, blending the solvents helps to improve the overall performance of the supercapacitor. The cells retained about 81% of the initial specific capacitance after 1000 galvanic cycles in the potential range of 0-2.5 V. Thus, LiBOB/ACN:PC electrolytes exhibit a promising role in supercapacitor applications under elevated temperature conditions.

Effect of centrifugation on tryptic protein digestion

  • Kim, Soohwan;Kim, Yeoseon;Lee, Dabin;Kim, Inyoung;Paek, Jihyun;Shin, Dongwon;Kim, Jeongkwon
    • Analytical Science and Technology
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    • v.30 no.2
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    • pp.96-101
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    • 2017
  • This study investigated the effect of centrifugation on tryptic digestion. This was done by applying different centrifugation speeds (6,000, 8,000, 10,000, 20,000, and $30,000{\times}g$) over various durations (0, 10, 20, 30, 40, 50, and 60 min) to digest two model proteins - cytochrome c and myoglobin. The intact proteins and resulting peptides were identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Centrifugation greatly improved the tryptic digestion efficiency of cytochrome c, where either an increase in centrifugation speed or in digestion duration significantly improved the digestion of cytochrome c. However, centrifugation did not noticeably improve the digestion of myoglobin; 16 h of centrifuge-assisted tryptic digestion at $30,000{\times}g$ barely removed the myoglobin protein peak. Similar results were also obtained when using conventional tryptic digestion with gentle mixing. When acetonitrile (ACN) was added to make 10% ACN buffer solutions, the myoglobin protein peak disappeared after 6 h of digestion using both centrifuge-assisted and conventional tryptic digestions.

Development of L-THIA sub-daily flow-water quality prediction system (L-THIA 시단위 유량-수질 예측 시스템 개발)

  • Gwanjae Lee;Yonghun Choi;Seoro Lee;Kyoung Jae Lim
    • Proceedings of the Korea Water Resources Association Conference
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    • 2023.05a
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    • pp.262-262
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    • 2023
  • 기후변화 및 도시화에 따른 강우 패턴의 변화는 수문 변화를 야기시키며, 이에 따른 영향을 평가하고 예측하기 위해서는 수문학적 모델을 통해 정량화하는 과정이 필요하다. 그러나 기존에 개발되어 사용되고 있는 대부분의 수문학적 모델은 해외에서 개발되어 국내 유역 특성을 반영하지 못하는 한계가 있다. 이러한 한계점을 극복하기 위해서 L-THIA ACN-WQ 2016과 2018 모델이 개발되어 적용성이 평가된 바 있다. 하지만 L-THIA ACN-WQ 모델의 경우 시단위 유량 및 수질 모의가 불가능한 한계점이 있다. 소규모 유역이나 도시화된 지역에서는 하루에 여러 번의 강우 이벤트가 발생하거나 단기간에 많은 양의 강우가 발생하는 경우가 많기 때문에, 이러한 강우-유출을 평가하기 위해서는 시단위 모의가 필요하다. 본 연구에서는 시단위 유량-수질 모의가 가능한 L-THIA sub-daily WQ 모델을 개발하였으며, 갑천 유역과 복하천 유역에서 적용성을 평가하였다. L-THIA sub-daily WQ 모델은 SCS-CN 방법과 Green-Ampt 방법을 함께 고려할 수 있도록 개발하였으며, 국내의 토지이용 및 강우 특성을 고려할 수 있도록 점근 CN과 강우 계급별 EMC를 활용하였다. 갑천 유역과 복하천 유역에서 시단위 유량 예측 결과 R2는 0.61~0.69, NSE는 0.61~0.65, PBIAS는 -4.0~-7.3으로 모의된 시단위 유량이 자연현상을 잘 모의하는 것으로 나타났으며, 수질 예측 결과 T-P와 SS가 자연현상을 잘 모의하는 것으로 나타났다. 따라서, 본 연구에서 개발된 L-THIA sub-daily WQ 모델은 점오염원을 포함하고 있는 도시유역에서 비점오염원에 평가에 활용될 수 있을 것으로 사료된다.

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Etching Anisotropy Depending on the SiO2 and Process Conditions of NF3 / H2O Remote Plasma Dry Cleaning (NF3 / H2O 원거리 플라즈마 건식 세정 조건 및 SiO2 종류에 따른 식각 이방 특성)

  • Hoon-Jung Oh;Seran Park;Kyu-Dong Kim;Dae-Hong Ko
    • Journal of the Semiconductor & Display Technology
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    • v.22 no.4
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    • pp.26-31
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    • 2023
  • We investigated the impact of NF3 / H2O remote plasma dry cleaning conditions on the SiO2 etching rate at different preparation states during the fabrication of ultra-large-scale integration (ULSI) devices. This included consideration of factors like Si crystal orientation prior to oxidation and three-dimensional structures. The dry cleaning process were carried out varying the parameters of pressure, NF3 flow rate, and H2O flow rate. We found that the pressure had an effective role in controlling anisotropic etching when a thin SiO2 layer was situated between Si3N4 and Si layers in a multilayer trench structure. Based on these observations, we would like to provide further guidelines for implementing the dry cleaning process in the fabrication of semiconductor devices having 3D structures.

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Simultaneous Determination of Quinolones in Flatfish and Egg Using liquid Chromatography with Fluorescence Detection (액체크로마토그래피를 이용한 광어 및 계란 중 퀴놀론계의 동시분석법 개발)

  • Lee, Sang-Hee;Shim, You-Shin;Kim, Hyun-Ju;Choi, Yoon-Hee;Shin, Dong-Bin
    • Journal of Food Hygiene and Safety
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    • v.23 no.4
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    • pp.324-329
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    • 2008
  • An analytical method for the simultaneous determination of nine quinolones (QNs) namely, marbofloxacin, norfloxacin(IS), ciprofloxacin, danofloxacin, enrofloxacin, sarafloxacin, difloxacin, oxolinic acid, and flumequine in flatfish and egg was developed and validated using liquid chromatography with fluorescence detection (LC-FD). The samples were extracted using a traditional liquid-liquid extraction process; deproteinization was accomplished by the addition of trichloroacetic acid and acetonitrile (ACN), and defatting was performed with hexane. Chromatographic separation was achieved on a reverse phase C8 column with gradient elution using a mobile phase of 200 mM ammonium acetate buffer (pH 4.5) and ACN. The proposed method was validated according to the CODEX guideline. Mean recoveries of QNs from flatfish and egg were 89.6-106.5% with relative standard deviations (RSDs) below 15% at three different concentrations of 50, 100 and $500{\mu}g/kg$. Linearity was obtained with a correlation coefficient ($r^2$) of 0.9989-1.0000. The LOD for the investigated QNs was $1-16{\mu}g/kg$ depending on flatfish and egg. The present method can be applied simultaneously to determine QNs in muscle of flatfish and egg.

Discrimination of Domestic Rice Cultivars by Capillary Electrophoresis (Capillary Electrophoresis를 이용한 국내산 쌀의 품종 판별)

  • Rhyu, Mee-Ra;Kim, Eun-Young;Ahn, Mee-Ok;Kim, Sang-Sook
    • Korean Journal of Food Science and Technology
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    • v.30 no.6
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    • pp.1252-1258
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    • 1998
  • Capillary electrophoresis (CE) with rice proteins was used to discriminate 10 domestic rice cultivars in less than 25 min. Most cultivars were differentiated quickly and easily using P-ACN buffer system. CE of rice prolamins allowed classifying ten varieties of Korean rice into three groups. Peak h was characteristic peak for Dongjinbyeo, Gaehwabyeo and Yongnambyeo which were classified into the group of Dongjinbyeo. Chuchungbyeo, Odaebyeo, Mangeumbyeo and Bonggwangbyeo easily differentiated from the group of Dongjinbyeo by the absence of peak h which were classified into the group of Chuchungbyeo. Peak g typical for Illpumbyeo, Hwaseungbyeo and Hwayoungbyeo accounted for 70% of total peak area. They belong to the group of Illpumbyeo. Some cultivars showed specific peak patterns among ten cultivars, Illpumbyeo was differentiated from others by several peaks between peak c and peak f, and the peak d was apparently detected in Odaebyeo not in others. Other minor differences were also found within each group. The result of the study showed that CE has potential for discrimination of rice cultivars. It also possesses the inherent advantages such as low mass requirements, fast seperations, and quantitative analysis through on-capillary UV detection.

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