전남지역 일부 대학생 모발 중 수은 농도에 관한 연구

송미라,조태진,전혜리,김종오,손부순,Song, Mi-Ra,Cho, Tae-Jin,Jeon, Hye-Li,Kim, Jong-O,Son, Bu-Soon 한국환경보건학회 2009 한국환경보건학회지 Vol.35 No.4

This study analysed the mercury concentration in the hair of 62 students (male : 21, female : 41) of D university in Najusi, Jeon-Nam area. Also, questionnaire, which developed by NIES, were completed by the students. According to the questionnaire, most of the students had a higher intake of meat than that of fish. Also, among the students, there were many smokes and many had dental treatment with amalgam. Based on the gender, female showed 1.024 ${\mu}g/g$ and male showed 0.882 ${\mu}g/g$ of the mercury concentration. This means that female students had higher level of mercury in their hair, but it was not a significant statistic difference. Comparing by the intake frequency of meat, processed food stuffs, protein foods, it shows the more they at the higher mercury concentration was observed. According to the intake frequency of fish, when the number of times they intake increased, the mercury concentration was higher. Under one time was 0.857 ${\mu}g/g$ and twice or more times were 1.152 ${\mu}g/g$, which showed a significant statistical difference (p<0.05). Depending on the Life style, the mercury concentration in the hair was high with workout, outdoor activities, and direct smoking. The mercury concentration in the hair showed no difference for whether they received amalgam treatment but the personal dietary habit and the Living condition affects strongly on the mercury concentration level.

철근 이음형 PC 보-기둥 내부 접합부의 구조적 거동에 관한 실험적 연구

김승훈,하상수,문정호,이리형,이강철,전병갑 대한건축학회 2004 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.24 No.1(구조계)

In this study, new moment-resisting precast concrete beam-column joint is proposed for moderate seismic regions. It has the connection reinforcing bars, penetrated the joint and lap-spliced with the bottom bars of precast U-beam. An experimental study was carried out to investigate the joint behavior subjected to reverse cyclic loading and constant axial compressive load. Three precast beam-column interior were tested. The variables examined were the type of connection reinforcing bars and presence of transverse reinforcement in joint. Joint performance is evaluated on the basis of connection .strength, stiffness, energy dissipation, and drift capacity. Based on the test results, the precast connection is capable of matching or exceeding the performance of the monolithic connection and thereby provides the sufficient moment-resisting behavior to be applicable for moderate seismic regions.

Overproduction of recombinant <i>E. coli</i> malate synthase enhances <i>Chlamydomonas reinhardtii</i> biomass by upregulating heterotrophic metabolism

Paik, Sang-Min,Kim, Joonwon,Jin, EonSeon,Jeon, Noo Li Elsevier 2019 Bioresource technology Vol.272 No.-

<P><B>Abstract</B></P> <P>High uptake of malate and efficient distribution of intracellular malate to organelles contributed to biomass increase, reducing maintenance energy. In this study, transgenic <I>Chlamydomonas reinhardtii</I> was developed that stably expresses malate synthase in the chloroplast. The strains under glyoxylate treatment showed 19% more increase in microalgal biomass than wild-type. By RNA analysis, transcript levels of malate dehydrogenase (<I>MDH4</I>) and acetyl-CoA synthetase (<I>ACS3</I>), isocitrate lyase (<I>ICL1</I>) and malate synthase (<I>MAS1</I>), were significantly more expressed (17%, 42%, 24%, and 18% respectively), which was consistent with reported heterotrophic metabolism flux analysis with the objective function maximizing biomass. Photosynthetic F<SUB>v</SUB>/F<SUB>m</SUB> was slightly reduced. A more meticulous analysis is necessary, but, in the transgenic microalgae with malate synthase overexpression, the metabolism is likely to more rely on heterotrophic energy production via TCA cycle and glyoxylate shunt than on photosynthesis, resulting in the increase in microalgal biomass.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Chloroplastic transgenic <I>C. reinhardtii</I> was developed that stably expressed malate synthase. </LI> <LI> This transgenic strain showed a more 19% increase in dry cell weight than wild-type strain. </LI> <LI> Transcripts of <I>MDH4</I>, <I>ACS3</I>, <I>ICL1</I>, and <I>MAS1</I> were increased, and F<SUB>v</SUB>/F<SUB>m</SUB> was decreased. </LI> <LI> Upregulation of heterotrophic metabolism might be involved in biomass increase. </LI> <LI> This could serve as a valuable strain for treating wastewater containing acetate and glyoxylate. </LI> </UL> </P>

Microfluidic platform for single cell analysis under dynamic spatial and temporal stimulation

Song, Jiyoung,Ryu, Hyunryul,Chung, Minhwan,Kim, Youngtaek,Blum, Yannick,Lee, Sung Sik,Pertz, Olivier,Jeon, Noo Li Elsevier 2018 Biosensors & bioelectronics Vol.104 No.-

<P><B>Abstract</B></P> <P>Recent research on cellular responses is shifting from static observations recorded under static stimuli to real-time monitoring in a dynamic environment. Since cells sense and interact with their surrounding microenvironment, an experimental platform where dynamically changing cellular microenvironments should be recreated <I>in vitro</I>. There has been a lack of microfluidic devices to support spatial and temporal stimulations in a simple and robust manner. Here, we describe a microfluidic device that generates dynamic chemical gradients and pulses in both space and time using a single device. This microfluidic device provides at least 12h of continuous stimulations that can be used to observe responses from mammalian cells. Combination of the microfluidic de­vice with live-cell imaging facilitates real-time observation of dynamic cellular response at single cell level. Using stable HEK cells with biosensors, ERK (Extracellular signal-Regulated Kinase) activities were observed un­der the pulsatile and ramping stimulations of EGF (Epidermal Growth Factor). We quantified ERK activation even at extremely low EGF concentration (0.0625µg/ml), which can not be observed using conventional techniques such as western blot. Cytoskeleton re­arrangement of the 3T3 fibroblast (stable transfection with Lifeact-GFP) was compared under abrupt and gradually changing gradient of PDGF.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A long-term live cell monitoring was performed under the spatial and temporal dynamic stimulations. </LI> <LI> Versatile stimulation profiles were generated in a single device without further modification. </LI> <LI> Quantitative observation of the persistent ERK activation with the increasing concentrations of EGF was made initially. </LI> <LI> Prior to the development of our device, ramping down stimulation of certain matters was unable to be achieved. </LI> <LI> Dynamically changing gradients were proposed and can be applied in directed cell migration. </LI> </UL> </P>

Investigation of natural convection heat transfer around a radial heat sink with a perforated ring

Li, Bin,Jeon, Sora,Byon, Chan Elsevier 2016 INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER - Vol.97 No.-

<P><B>Abstract</B></P> <P>Numerical studies were performed on natural convection heat transfer from radial heat sinks with perforated ring. The effects of perforation number (0–6), perforation diameter (0–3mm), and perforation length (1.5–6mm), and orientations angle (0–180°) on the thermal performance were investigated. The results show that radial heat sinks with a perforated ring obviously have better thermal performance than that with imperforated ring. Upwardly oriented radial heat sinks have the best thermal performance while sideward oriented radial heat sinks yield worst thermal performance. The geometric parameters of perforation is shown to affect the thermal performance of heat sink significantly at relatively higher heat transfer rate, especially for upward and sideward orientations. The thermal resistance of the radial heat sink with optimized perforated ring was shown to be less than that of imperforated ring by 17%, while reducing the mass of ring by up to 37%. This can be attributed to the unhindered natural convective flow through the perforation.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The radial heat sink with concentric ring is considered. </LI> <LI> The effect of the perforation and orientation on the thermal performance is investigated numerically. </LI> <LI> The optimized perforated heat sink can reduce the thermal resistance and mass significantly. </LI> <LI> The performance enhancement is shown to be attributed to the unhindered natural convective flow. </LI> </UL> </P>

Zeolitic imidazolate frameworks derived novel polyhedral shaped hollow Co-B-O@Co₃O₄ electrocatalyst for oxygen evolution reaction

Kim, Dongwon,Kim, Daekyu,Jeon, Youngmoo,Li, Yong,Lee, Jeongyeon,Kang, Jeongmin,Lee, Lawrence Yoon Suk,Piao, Yuanzhe Elsevier 2019 ELECTROCHIMICA ACTA Vol.299 No.-

<P><B>Abstract</B></P> <P>The development of highly effective and low-cost non-noble metal electrochemical catalysts for oxygen evolution reactions (OER) is a major challenge for overall water splitting and rechargeable metal-air batteries. In this study, we develop a novel hollow cobalt-borate modified cobalt oxide composite (denoted by Co-B-O@Co<SUB>3</SUB>O<SUB>4</SUB>) catalyst derived from zeolitic imidazolate framework-67 (ZIF-67) for electrochemical OER. The Co-B-O@Co<SUB>3</SUB>O<SUB>4</SUB> was easily synthesized via pyrolysis of ZIF-67 in Ar and air to produce hollow Co<SUB>3</SUB>O<SUB>4</SUB> (denoted by h-Co<SUB>3</SUB>O<SUB>4</SUB>), followed by simple NaBH<SUB>4</SUB> treatment at ambient temperature for 4 h. The unique polyhedral morphology was well preserved during the NaBH<SUB>4</SUB> treatment. Benefiting from its structural and compositional merit, the as-synthesized Co-B-O@Co<SUB>3</SUB>O<SUB>4</SUB> exhibit excellent electrocatalytic activity and long-term stability for OER. Also, we conducted the OER test using a Co-B-O@Co<SUB>3</SUB>O<SUB>4</SUB> catalyst in a neutral pH environment for further investigation. Our study can provide an insight into catalyst modification step to enhance the overall performance while keeping its physical structure simultaneously. using metal-organic framework for the electrochemical catalyst thus can be recognized as a method for producing a highly active, long-term working and novel engineered electrocatalyst for OER applications.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Co-B-O@Co<SUB>3</SUB>O<SUB>4</SUB> was prepared using calcination-NaBH<SUB>4</SUB> treatment strategy with a facile and energy efficient method. </LI> <LI> A distinctive polyhedral morphology of Co-B-O@Co<SUB>3</SUB>O<SUB>4</SUB> was well preserved after the NaBH<SUB>4</SUB> treatment of its precursor material. </LI> <LI> Co-B-O@Co<SUB>3</SUB>O<SUB>4</SUB> was employed for the electrochemical oxygen evolution reaction. </LI> <LI> Co-B-O@Co<SUB>3</SUB>O<SUB>4</SUB> showed excellent catalytic performance and long-term durability for oxygen evolution reaction in basic media. </LI> </UL> </P>

Microfluidic perfusion bioreactor for optimization of microalgal lipid productivity

Paik, Sang-Min,Sim, Sang-Jun,Jeon, Noo Li Elsevier 2017 Bioresource technology Vol.233 No.-

<P><B>Abstract</B></P> <P>Nutrient deprivation in a batch process induces microbes to produce secondary metabolites while drastically constraining cellular growth. A microfluidic continuous perfusion system was designed and tested to culture microalgae, <I>Chlamydomonas reinhardtii</I>, under constant nutrient concentration slightly lower than normal condition. When cultured in 7.5%/7.5% of NH<SUB>4</SUB> <SUP>+</SUP>/PO<SUB>4</SUB> <SUP>2</SUP> <SUP>−</SUP>, <I>C. reinhardtii</I> showed a 2.4-fold increase in TAG production with a 3.5-fold increase in biomass compared to level obtained under an only NH<SUB>4</SUB> <SUP>+</SUP> depleted condition. The microfluidic continuous perfusion bioreactor with steady continuous nutrient flow can be used to optimize conditions for enhancing secondary metabolite production and increasing microbial biomass.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Microfluidic perfusion bioreactor is designed for secondary metabolite production. </LI> <LI> Continuous supply of low concentration of nutrient permits microbes to grow at a minimum rate. </LI> <LI> Low nutrient allows same level of metabolite production compared to depleted condition. </LI> <LI> Stable feed of low level of nutrient is an effective way to enhance total TAG yield. </LI> </UL> </P>

Vibration-induced stress priming during seed culture increases microalgal biomass in high shear field-cultivation

Paik, Sang-Min,Jin, EonSeon,Sim, Sang Jun,Jeon, Noo Li Elsevier Applied Science 2018 Bioresource technology Vol.254 No.-

<P><B>Abstract</B></P> <P>Vibrational wave treatment has been used to increase proliferation of microalgae. When directly applied at large scale, however, turbulence can offset positive effects of vibration on microalgae proliferation. Moreover, severe hydrodynamic shear fields in the bioreactor decrease cell viability that detrimentally influence maximum yieldable biomass. In this study, vibration pretreatment (between 10–30 Hz and 0.15–0.45 G) was used to prime the cells for enhanced biomass. When exposed to 10 Hz at 0.15 G for 72 h and inoculated in baffled flasks of large shear fields (0.292 Pa for the average wall shear force (aveWSF) and 184 s<SUP>−1</SUP> for the average shear strain rate (aveSSR)), microalgae showed 27% increase in biomass as well as 39% increase in corresponding amount of heterologous protein (i.e. GFP-3HA). Our results show that stress primed microalgae with vibrations can lead to improved proliferation that results in increased biomass production at industrial scale bioprocesses.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Vibration put microalgal cells into a primed state where to endure severe stresses. </LI> <LI> Primed microalgal cells grew more in harsh shear field-cultivation. </LI> <LI> Stress-priming can contributes to biomass increase and efficient large-scale bioprocess. </LI> <LI> TRP11 was cross-activated linking stresses from mild vibration and harsh shaking. </LI> </UL> </P>

Ash formation characteristics of two Indonesian coals and the change of ash properties with particle size

Ke, Xiwei,Li, Dongfang,Zhang, Man,Jeon, Chung-hwan,Cai, Runxia,Cai, Jin,Lyu, Junfu,Yang, Hairui Elsevier Scientific Pub. Co. 2019 Fuel processing technology Vol.186 No.-

<P><B>Abstract</B></P> <P>It is difficult to maintain enough high circulating ash rate in circulating fluidized bed (CFB) boilers if they burn the Indonesian coals due to their low ash content. Hence, the ash formation data for these coals is of significance to assessing mass balance in CFB boilers. Two kinds of Indonesian coal that were burned in the 550 MW supercritical CFB boilers in Korea, Kideco and KCH, were tested with static combustion and cold sieving method to study their ash formation characteristics. Results showed that the average primary ash particle size of these two coals is quite fine overall and nearly no gangue exists. Besides, their attrition rate constant <I>K</I> <SUB>af</SUB> is much higher than that of some other bituminous or lean coals, and with the increase of particle size, the <I>K</I> <SUB>af</SUB> decays exponentially for Kideco, while it initially increases and then decreases for KCH. In addition, the physical and chemical properties of these two Indonesian coals' ash obviously change in particle size, including density, pore structure, chemical composition, etc. The larger ash particles are composed of some hard materials, such as quartz (SiO<SUB>2</SUB>) and mullite (Al<SUB>6</SUB>Si<SUB>2</SUB>O<SUB>13</SUB>). While some other materials with lower hardness value, like hematite (Fe<SUB>2</SUB>O<SUB>3</SUB>) and gehlenite (Ca<SUB>2</SUB>Al<SUB>2</SUB>SiO<SUB>7</SUB>), become major mineral components of smaller and softer ash particles. These results indicate that the difference of chemical compositions results in the discrepancy of attrition capability for different size ash particles.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Two kinds of Indonesian coal were tested to obtain their ash formation data. </LI> <LI> The ash properties obviously change in particle size. </LI> <LI> The difference of chemical compositions may result in the discrepancy of attrition rate for different size ash particles. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>The ash attrition rate of low-rank coals including these two Indonesian coals is much higher than that of some other bituminous or lean coals, and larger ash particles are more difficult to be worn.</P> <P>[DISPLAY OMISSION]</P>

Quantum-dot nanoprobes and AOTF based cross talk eliminated six color imaging of biomolecules in cellular system

Park, Solji,Arumugam, Parthasarathy,Purushothaman, Baskaran,Kim, Sung-Yon,Min, Dal-Hee,Jeon, Noo Li,Song, Joon Myong Elsevier 2017 Analytica chimica acta Vol.985 No.-

<P><B>Abstract</B></P> <P>Primary cell cultures mimic the physiology and genetic makeup of in-vivo tissue of origin, nonetheless, a complication in the derivation and propagation of primary cell culture limits its use in biological research. However, in-vitro models using primary cells might be a complement model to mimic in vivo response. But, conventional techniques such as western blot and PCR employed to study the expression and activation of proteins requires a large number of cells, hence repeated establishment and maintenance of primary culture are unavoidable. Quantum dot (Q-dot) and acousto-optic tunable filters (AOTF) based multiplex imaging system is a viable alternative choice to evaluate multiple signaling molecules by using a small number of cells. Q-dots have broad excitation and narrow emission spectra, which allows to simultaneously excite multiple Q-dots by using single excitation wavelength. The use of AOTF in the fluorescence detection system enables to scan the fluorescence emission intensity of a Q-dot at their central wavelength, this phenomenon effectively avoids spectral overlap among the neighboring Q-dots. When Q-dots are conjugated with antibodies it acts as effective sensing probes. To validate this, the expression pattern of p-JNK-1, p-GSK3β, p-IRS1ser, p-IRS1tyr, p-FOXO1, and PPAR-γ, involved in the insulin resistance were concurrently monitored in adipocyte and HepG2 co-cell culture model. The observed results clearly indicate that PPAR-γ is the critical component in the development of insulin resistance. Moreover, the results proved that developed Q-dot based AOTF imaging methodology is a sensible choice to concurrently monitor multiple signaling molecules with limited cell population.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Quantum dot (Q-dot) and acousto-optic tunable filters (AOTF) based six-colour imaging. </LI> <LI> Expression of PPAR-γ in adipocyte regulates insulin resistance in hepatic (HepG2) cells. </LI> <LI> Aspirin improved insulin sensitivity in adipocytes and HepG2 co-cell culture. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>