Precise determination of the lithium isotope ratio in geological samples using MC-ICP-MS with cool plasma

Choi, Min Seok,Ryu, Jong-Sik,Park, Ha Yan,Lee, Kwang-Sik,Kil, Youngwoo,Shin, Hyung Seon The Royal Society of Chemistry 2013 Journal of analytical atomic spectrometry Vol.28 No.4

<P>Lithium has two naturally occurring isotopes, <SUP>6</SUP>Li and <SUP>7</SUP>Li, with approximate relative abundances of 7.5% and 92.5%, respectively. Due to large Li isotope variations in nature, lithium isotopes have the potential to reveal important information relevant to nuclear technology, biomedicine, astrophysics, and geochemistry. With the advent of multi-collector inductively coupled mass spectrometry (MC-ICP-MS), studies of Li isotopes have largely focused on the analysis of geological materials, with varying degrees of accuracy. However, this technique has often been affected by either baseline interferences or isobaric interferences on mass 6 and 7 during ionization in Ar plasma, which is mainly due to the Li compound with hydrogen gas, and double-charged nitrogen and carbon ions at higher levels of RF power. In this study, we reduced baseline interferences in Ar plasma using a cool plasma (∼800 W) technique with a X-type cone. Lithium was separated using a cation exchange column (BioRad AG50W-X8, 200–400 mesh) with a mixture of 6 N HNO<SUB>3</SUB> and 80% methanol at <0.2 mL min<SUP>−1</SUP> elution speed. The short-term reproducibility of <I>δ</I><SUP>7</SUP>Li values of the NASS-5 seawater standard was 30.55 ± 0.45‰ (2<I>σ</I>, <I>n</I> = 15). Measured <I>δ</I><SUP>7</SUP>Li values of rock and seawater standards ranged from 2.48 to 30.55‰, in good agreements with reported values.</P> <P>Graphic Abstract</P><P>Average <I>δ</I><SUP>7</SUP>Li values of a pure L-SVEC Li solution and one passed through the column were 0.00 ± 0.23‰ (2<I>σ</I>, <I>n</I> = 26) and ¬0.01 ± 0.20 ‰ (2<I>σ</I> , <I>n</I> = 9), respectively, indicating that our chemical separation procedure for Li induces no mass fractionation. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c2ja30293d'> </P>

간헐식 흐름방식을 활용한 수직 · 수평 습지의 정화효율 평가

주광진(Kwang Jin Joo),이동민(Dong Min Lee),김기중(Ki Jung Kim),조용철(Yong Chul Cho),장광현(Gwang Hyeon Jang),최이송(I Song Choi),오종민(Jong Min Oh) 응용생태공학회 2017 Ecology and resilient infrastructure Vol.4 No.3

본 연구에서는 부영양화의 원인이 되는 질소와 인의 제거 효율을 향상시킬 목적으로 광물질을 활용한 여재를 이용하여 호기, 혐기의 흐름조건을 만들어주기 위한 수직·수평 흐름 인공습지를 고안하여 아크릴 반응조로 제작한 후 성능평가를 진행하였다. 수직·수평 흐름형 인공습지의 경우 호기 및 혐기조건을 평가하기 위해서 반응조 내 용존산소(DO) 농도를 측정해본 결과 호기상태에서는 2.7 ㎎/L, 혐기상태에서는 N.D로 확인되어 목적에 부합된 결과가 확인되었다. 실험결과에서는 SS 저감효과가 140 min, 80 min, 60 min의 운전시간에서 각각 94%, 91%, 61%의 효율을 보였고, T-P의 경우 각각의 운전시간에 따라 84%, 71%, 63%의 저감효율을 보였다. 또한 T-N의 경우 각각의 운전시간에 따라 63%, 49%, 42%의 저감효율을 보여 기존의 습지가 12~24 hr 체류시간을 가지는 것에 비하여 짧은 운전시간에도 높은 처리효율을 보이는 것으로 확인되었다. 본 연구에서는 수직·수평 흐름 방식을 복합 적용하여 기존 인공습지의 단점을 보완하기 위해 기술개발을 진행한 것으로 어떠한 기능적 효과를 갖는지 확인하였고, 향후 이에 대한 현장적용을 위한 운영 및 관리적 차원의 메커니즘 연구가 추가로 진행 될 필요가 있다. Nitrogen and phosphorus are key factors in causing eutrophication of water body. In this study, ceramics media was selected to increase the removal efficiency of nitrogen and phosphorus. We designed vertical, horizontal flow constructed wetlands to create aerobic and anaerobic flow conditions by using the media, then proceeded to performance evaluations after acrylic reactors were produced. In the case of vertical and horizontal flow constructed wetlands, we measured oxygen concentrations to evaluate aerobic and anaerobic conditions. we got the result of 2.7 ㎎/L in the aerobic condition, N.D in the anaerobic condition respectively, which suited our purpose. The result of the combined vertical and horizontal flow condition showed that the removal efficiency of SS was 94%, 91%, 61% at 140 min, 80 min, 60 min of running times, respectively, and the removal efficiency of T-P was 84%, 71%, 63% during each running time. In case of T-N, the removal efficiency was 63%, 49%, 42% during each running time. We found that the reactor exerted better removal efficiency when in the short time compared to 12 - 24 hr residence time of existing wetlands. In this study, we conducted experiments to explore functional effects after applying combined vertical and horizontal flow methods in the field. Further study will be carried out to identify its mechanism and administrative perspective.

Studies on Lytic, Tailed Bacillus cereus-specific Phage for Use in a Ferromagnetoelastic Biosensor as a Novel Recognition Element

( In Young Choi ),( Joo Hyeon Park ),( Kyoung Min Gwak ),( Kwang-pyo Kim ),( Jun-hyun Oh ),( Mi-kyung Park ) 한국미생물생명공학회(구 한국산업미생물학회) 2018 Journal of microbiology and biotechnology Vol.28 No.1

This study investigated the feasibility of the lytic, tailed Bacillus cereus-specific phage for use in a ferromagnetoelastic (FME) biosensor as a novel recognition element. The phage was immobilized at various concentrations through either direct adsorption or a combination of 11-mercapto-1-undecanoic acid (11-MUA) and [N-(3-dimethylaminopropyl)-N’-carbodiimide hydrochloride and N-hydroxysuccinimide (EDC/NHS)]. The effects of time and temperature on its lytic properties were investigated through the exposure of B. cereus (4 and 8 logCFU/ml) to the phage (8 logPFU/ml) for various incubation periods at 22°C and at various temperatures for 30 and 60 min. As the phage concentration increased, both immobilization methods also significantly increased the phage density (p < 0.05). SEM images confirmed that the phage density on the FME platform corresponded to the increased phage concentration. As the combination of 11-MUA and EDC/NHS enhanced the phage density and orientation by up to 4.3-fold, it was selected for use. When various incubation was conducted, no significant differences were observed in the survival rate of B. cereus within 30 min, which was in contrast to the significant decreases observed at 45 and 60 min (p < 0.05). In addition, temperature exerted no significant effects on the survival rate across the entire temperature range. This study demonstrated the feasibility of the lytic, tailed B. cereus-specific phage as a novel recognition element for use in an FME biosensor. Thus, the phage could be placed on the surface of foods for at least 30 min without any significant loss of B. cereus, as a result of the inherent lytic activity of the B. cereus-specific phage as a novel recognition element.

대장직장 종양에 대한 내시경 점막하 절제술의 연대순 임상 결과와 학습 곡선

이상민 ( Sang Min Lee ),김은수 ( Eun Soo Kim ),박경식 ( Kyung Sik Park ),조광범 ( Kwang Bum Cho ),김동춘 ( Dong Choon Kim ),강유진 ( Yu Jin Kang ),이유진 ( Yoo Jin Lee ),이정민 ( Jung Min Lee ),최은성 ( Eun Sung Choi ),최재혁 ( Ja 대한소화기학회 2014 대한소화기학회지 Vol.64 No.4

Background/Aims: Endoscopic submucosal dissection (ESD) is an effective procedure for en-bloc curative resection of the colorectal tumor. As it requires high technical skills and experience in therapeutic endoscopy, it is important to understand learning curve of ESD technique. The aim of this study was to retrospectively describe the clinical results of ESD and to evaluate learning curve for the ESD of colorectal tumors. Methods: A total of 90 patients with 90 colorectal neoplasms, who had undergone ESD at a tertiary referral hospital from July 2009 to December 2012, were enrolled. The ESD was performed by a single endoscopist. All ESD cases were divided into three periods: first, cases 1-30; second, cases 31-60; and third, cases 61-90. Results: The en-bloc resection rates in third period (100%) was significantly higher than that of the first (93.3%) and second period (80%) (p=0.025). The perforation rate in third period (0%) also significantly decreased compared with that of the first (13.3%) and second period (20%) (p=0.032). To calibrate the difference of tumor size among periods, proficiency was calculated, as the procedure time per specimen area (min/cm2). The proficiency in third period (4.3) was significantly shorter than that of the first (16.8) and second period (10.2) (p=0.004). Conclusions: The learning curve of colorectal ESD in our study shows that at least 60 cases of ESD have to be conducted to acquire sufficient skill of degree without perforation. (Korean J Gastroenterol 2014;64:198-205)

열처리 방법에 따른 표고버섯의 이화학적 특성 및 영양학적 분석

이중규(Jung-Gyu Lee),김광일(Kwang-Il Kim),황인국(In-Guk Hwang),유선미(Seon-Mi Yoo),민상기(Sang-Gi Min),최미정(Mi-Jung Choi) 한국식품영양과학회 2015 한국식품영양과학회지 Vol.44 No.6

본 연구는 열수 침지, 증기 및 볶음 처리가 표고버섯에 미치는 이화학적 분석 및 영양성분 분석을 통해 최적 열처리 조건을 확립하고자 진행하였다. 소비자들이 상품을 평가할 때 1차적으로 먼저 관찰되는 색도와 경도를 측정하고 추가로 pH 측정 등으로 인한 이화학적 결과로 최적 조건을 선정한 뒤에 그 조건들에 대해서 영양학적 및 미생물 검사를 실시하였다. 색도는 열처리 시간이 길어질수록 색의 변색 정도가 증가하여 뚜렷한 차이를 나타내었다. pH 값은 열수 침지 처리의 경우 pH 증가량이 가장 높았으며 처리 시간이 지속될수록 pH가 증가하는 경향을 나타내었다. 다른 처리군의 경우 일정 시간의 처리 시간 이후에는 유의적인 차이를 보이지 않았다. 경도에서는 열수 침지와 볶음 처리의 경우 1분 이내의 열처리만으로도 경도가 감소하는 경향을 보였으며, 증기처리의 경우 1분 동안 경도가 유지되는 결과를 보였다. 일반성분 분석 결과는 증기 처리가 가장 원물에 가까운 결과를 나타냈다. 유기산 함량은 증기 처리에서 유기산 함량 감소율이 가장 낮았다. 또한 3분간 증기 처리를 하였을 때 미생물의 사멸 효과가 가장 높았다. 열수 침지 처리나 볶음 처리의 경우 전체적으로 증기 처리한 시료에 비해서 영양성분 함량이 줄어드는 경향을 나타냈다. 따라서 표고버섯을 증기 처리방법으로 열처리하는 것이 다른 열처리군에 비해서 최적으로 나타났다. 하지만 본 연구에서는 물리화학 및 영양학적 성분의 변화만을 분석하였기 때문에 실제 식품 산업이나 공정에 적용하기 위해서는 대용량 처리 시에 발생하는 문제들과 관련된 추가적인 연구를 필요로 할 것이다. In the food industry, thermal treatment is an important process for extending shelf-life of foods. However, heating process affects the physicochemical, nutritional, and microbial properties of foodstuff such as color, texture, pH, and proximate compositions. This study was conducted to select an optimal thermal treatment by observing physicochemical, nutritional, and microbial effects of shiitake mushrooms with different thermal treatment methods. Shiitake mushrooms were washed and sliced equally (5 cm×0.5 cm×0.5 cm) and then heat-treated by three methods. Samples were heated in 100°C boiling water, steamed for 10 min, or pan fried at 130°C for 4 min. Total color difference values showed significantly increasing tendency with treatment time. For pH values, boiling water-treated mushrooms showed increasing tendency according to increased thermal treatment. For the results of hardness, boiling water or pan frying-treated mushrooms showed reduced tendency within 1 min. In the case of steam-treated mushrooms, hardness values were maintained for 1 min. Organic acid contents of steam-treated sample showed the lowest value among treatments. For microbial counts, steam-treated samples for 3 min showed the lowest value. Consequently, the results of this study suggest that steam treatment could be the optimal thermal treatment to minimize quality loss of shiitake mushrooms.

허혈성 심질환에 있어서 아데노신 급속 정맥투여후 관동맥압의 변화에 관한 연구

봉종대,오종용,배성한,신원용,김철현,이광희,최태명,현민수,김성구,권영주 순천향의학연구소 1998 Journal of Soonchunhyang Medical Science Vol.4 No.2

Background: Adenosine interacts with A1 receptors present on the extracellular surface of cardiac cells, activating K+channels in a fashion. It produces coronary vasodilatation and AV nodal block. The half-time is one to six second and has ultra-short action. In ischemic heart disease, fractional flow reserve(FFR) can be achieved safely with intravenous adenosine infusions at a rate of 150㎍/kg/min which cause maximal coronary hyperemia. Purpose: We investigated the patients who have had ischemic heart disease(n=8). After adenosine intravenous administration(150㎍/kg/min), the effect cause maximal hyperemia of coronary artery. During peak maximal hyperemia, we reported clinical findings, coronary hemodynamics and electrocardiogram findings. Methods: After diagnostic coronary angiography and left ventriculography, catheter was advanced into the ostium of coronary artery. We investigated coronary hemodynamics such as systolic coronary artery pressure, diastolic coronary artery pressure, mean coronary artery pressure and heart rate. To assess the use of adenosine for determination of fractional flow reserve, hemodynamics and electrocardiogram were measured at basal state and during peak maximal hyperemia. Results: Symptoms developed 1.5-2 minute after adenosine intravenous administration and each symptom disappeared 2-2.5 minute after adenosine administration. Two patients represented asymptomatic appearance and six patients complained of flushing, chest pain, palpitation and headache. In eight patients with ischemic heart disease, 1.5 minute after venous administration of 150㎍/kg/min of adenosine, coronary artery pressure decreased and heart rate increased significantly. Conduction abnormalities after administration of 150㎍/kg/min of adenosine were transient 2nd degree AV block 2 cases(25%). Conclusions: Adenosine is a potent ultra short-acting vasodilator. Although coronary artery pressure decreased and heart rate increased and mild cardiovascular symptoms occurred after continuous infusion of 150㎍/kg/min of adenosine, it is useful as an agent for determination of fractional flow reserve.

국산 Lidocaine 알칼리화를 위한 Bicarbonate 혼합시 침전유발 최소량에 대한 고찰

이선호,김현수,곽인숙,안원식,최관호,김광민,손민제 대한마취과학회 2000 Korean Journal of Anesthesiology Vol.39 No.5

Background : When local anesthetics for regional anesthesia is used, usually small amounts of bicar-bonate are added for rapid onset. This addition gives the mixed solution a more alkaline pH. The following result is an increased unionized form of the local anesthetic and rapid penetration of the drug into tiissue. Unfortunately, no data about adequate mixing volumes of domestic lidocaine and bicarbonate is available. Methods : We examined six mixing pairs of two kinds of 2% lidocaines and three kinds of 8.4% bicarbonates for minimum volumes of bicarbonate to cause a precipitation of 2% 20 ml lidocaine. Results : The mean volumes of bicarbonate to cause precipitation were 1.54 ml for Kwang-Myung lidocaine with Kwang-Myung bicarbonate, 2.90 ml for Kwang-Myung lidocaine with Dae-Won bicarbonate, 2.73 ml for Kwang-Myung lidocaine with Je-Il bicarbonate, 0.97 ml for Je-Il lidocaine with Kwang-Myung bicarbonate, 1.26ml for Je-Il lidocaine with Dae-Won bicarbonate and 1.39 ml for Je-Il lidocaine with Je-Il bicarbonate. Conclusions : We conclude that the Kwang-Myung lidocaine and the Je-Il lidocaine could cause precipitation when mixing with a smaller bicarbonate volume than foreign textbook recommended. (Korean J Anesthesiol 2000; 39: 726-729)

알루미늄 PEO 코팅의 결정상에 미치는 공정 조건에 대한 연구 I. Unipolar 펄스와 코팅시간

김배연,함재호,이득용,김용남,전민석,김기윤,최지원,김성엽,김광엽,Kim, Bae-Yeon,Ham, Jae-Ho,Lee, Deuk Yong,Kim, Yong-Nam,Jeon, Min-Seok,Kim, Kiyoon,Choi, Ji-Won,Kim, Sung Youp,Kim, Kwang Youp 한국결정성장학회 2014 韓國結晶成長學會誌 Vol.24 No.2

전해질로 $Na_2SiO_3$을 사용하여 A1050 알루미늄 판재를 pulse 폭 $ 2000{\mu}sec$, impulse 420 V, 400 ${\mu}$sec의 unipolar pulse로 플라즈마 전해 산화 코팅(plasma electrolytic oxidation coating)을 하여 산화 피막을 2, 5, 15, 30분에 따라 형성시킨 다음 산화피막을 분석하였다. 표면에 형성된 산화물의 결정상은 ${\alpha}-alumina$와 ${\gamma}-Alumina$로서 시간에 따른 변화는 없었다. 반응 초반에는 ${\gamma}-Alumina$가 많이 생성되었지만 시간이 갈수록 ${\gamma}-Alumina$의 양에는 변화 없이 ${\alpha}-alumina$가 많이 생겨남을 알 수 있었다. 이런 결과는 micro plasma에 의해서 ${\gamma}-Alumina$가 우선 생성되고, 이후 계속되는 micro plasma의 열에 의해서 ${\alpha}-alumina$로의 전이가 일어나기 때문으로 판단된다. Crystallographic phases of Plasma electrolytic oxidized Al alloy, A1050, were investigated. The electrolyte of PEO was $Na_2Si_2O_3$ and KOH. Unipolar pulse, $ 2000{\mu}sec$ with $400{\mu}sec+420V$ impulse, were applied for 2 min, 5 min, 15 min, and 30 min. ${\gamma}-Alumina$, as well as ${\alpha}-alumina$, was main crystal phase. ${\gamma}-Alumina$ was appeared in the beginning, then the amount of ${\alpha}-alumina$ was increased with time, but the amount of ${\gamma}-Alumina$ remained constant without any increasing. So, it is concluded that plasma gas produce ${\gamma}-Alumina$ at the first, and then ${\gamma}-Alumina$ transform ${\alpha}-alumina$ finally. During the transformation, high temperature of micro plasma gives transformation energy.

한국인에서 구강상피세포를 이용한 발암물질 대사효소의 유전자 다형성에 관한 연구

최민아,박해준,정원윤,이재원,이정복,박광균 대한암예방학회 2002 Journal of cancer prevention Vol.7 No.3

ISI 프로토콜에서의 인증에 관한 연구

최길림,이재동,정광민 慶南專門大學 2000 論文集 Vol.28 No.1