• Korean Journal of Microbiology
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• v.51 no.3
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• pp.241-248
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• 2015

Although studies on probiotics have been performed mostly with viable microbes, the beneficial functions of dead or heat-killed form of probiotic strains have also been examined. In this study, live and heat-killed forms of Lactobacillus acidophilus CBT LA1 were investigated in vitro and in vivo to evaluate the properties necessary for gut barrier protection. Cell surface hydrophobicity (CSH), autoaggregation (AA), cell adhesion, and lipopolysaccharide (LPS)-binding properties were evaluated. In addition, the suppressive effect on LPS-induced interleukin (IL)-8 expression was investigated in HT-29 cells. To identify optimal conditions for CBT LA1 to adhere to HT-29 cells, CBT LA1 cells were heat-treated at 80, 85, 90, 95, 100, or $121^{\circ}C$ for 10 min; cells treated at $80^{\circ}C$ for 10 min showed the highest adhesion. Heat-killed bacteria at $80^{\circ}C$ showed higher levels of LPS-binding, CSH, AA, adhesion to HT-29, and suppression of IL-8 expression than did live CBT LA1. In vivo imaging was performed to evaluate the ability of live or heat-killed CBT LA1 to remove LPS from the intestine in a rat model of infection. At 16 h after infection, fluorescence from FITC-conjugated LPS had mostly disappeared from the intestine of the rats administered with live or heat-killed CBT LA1; the effect was greater with heat-killed CBT LA1 at $80^{\circ}C$. These results suggest that heat-killed CBT LA1 as well as its live form can be applied as a pharmabiotic for protection of the gut barrier.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.15 no.1
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• pp.8-15
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• 2010

An experiment was conducted to evaluate the biologically adverse effect of increased carbon dioxide in seawater on marine bacteria, Vibrio fischeri. We measured the bioluminescence and cell density at every 6 hours for 24 hours of the whole incubation period after exposing test microbes to a range of $CO_2$ concentration such as 380(Control), 1,000, 3,000, 10,000 and 30,000 ppm, respectively. Significant effect on relative luminescence(RLU) of V. fischeri was observed in treatments with $CO_2$ concentration higher than 3,000 ppm at t=12 h. However, the difference of RLU among treatments significantly decreased with the incubation time until t=24 h. Similar trend was observed for the variation of cell density, which was measured as optical density using spectrophotometer. The results showed that a significant relationship between $CO_2$ concentration and bioluminescence of test microbes was observed for the mean time. However, the inhibition of relative bioluminescence and also cell density could be recovered at the concentration levels higher than 3,000 ppm. The dissolved $CO_2$ can be absorbed directly by cell and it can decrease the intracellular pH. Our results implied that microbes might be adversely affected at the initial growing phase by increased $CO_2$. However, they could adapt by increasing ion transport including bicarbonate and then could make their pH back to normal level. Results of this study could be supported to understand the possible influence on marine bacteria by atmospheric increase of $CO_2$ in near future and also by released $CO_2$ during the marine $CO_2$ sequestration activity.

• Journal of information and communication convergence engineering
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• v.4 no.4
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• pp.170-173
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• 2006

Recently, with increasing efficiency of DSC (photo-electrochemical using a nano-particle), The Performance of DSC solar generation system also needs improvement. The approach consists of a Fly-back DC-DC (transfer ratio 1:10) converter to boost the DSC cell voltage to 300VDC. The four switch (MOSFET) inverter is employed to produce 220V, 60Hz AC outputs. High performance, easy manufacturability, lower component count., safety and cost are addressed. Protection and diagnostic features form an important part of the design. Another highlight of the proposed design is the control strategy, which allows the inverter to adapt to the: requirements of the load as well as the power source. A unique aspect of the design is the use of the DSP TMS320LF2406 to control the inverter by current and voltage feed-back. Efficient and smooth control of the: power drawn from the DSC Cell is achieved by controlling the front end DC-DC converter in current mode.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.143.2-143.2
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• 2010

Therefore, with this development assignment we'd like to develop the hybrid system combining 800W DMFC (Direct Methanol Fuel Cell) and 1.6kW of Lithium secondary battery pack which can be applied to the most common small cart. a scooter, to secure the development capability of hundreds of Watts DMFC, the high-capacity Lithium secondary battery pack, the technology of BMS (Battery Management System) and the development technology of hybrid system. DMFC, in fact, has lower energy efficiency than PEMFC (Polymer Electrolyte Membrane Fuel Cell); however, it has several advantages in terms of fuel storage and use. It is pretty easy to be stored and used without any additional colling and heating devices because of its insensitive liquid methanol to temperature. In conclusion, DMFC system is the most suitable device for small mobile vehicles.

• Journal of Environmental Health Sciences
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• v.27 no.1
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• pp.100-105
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• 2001

Microstructural examinations were performed on the anaerobic biofilm from reactor filled with PE support media. Optical microscope, SEM and fluorescent microscope were used for qualitative and morphological studies on the attached microorganism under anaerobic condition. Microorganisms were attached in crevices where protection from shear forces of surfaces where easy to contact with support media surface. A hypothesis for biofilm accumulation occurs on a surface such as polymer support media is presented schematically : 1st step ; cell-support media attachment, 2nd step ; cell-support media attachment and cell-cell attachment, 3rd step ; attached biofilm from neighboring crevices joins together and growing, 4th step ; mature and irregualar biofilm was formed. In SEM photographs, shape and structures of biofilm were observed, but microorganism species and methanogens were not identified. A large number of methanogenic bacteria were identified on the surface of PE substratum by fluorescence under 480nm of radiation and it was estimated that methanogenic bacteria was related to initial attachment of bacteria under anaerobic condition.

• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.3-12
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• 1991

Fuel cells are electrochemical devices that convert the chemical reaction energy directly into the electrical energy. In a typical fuel cell, gaseous fuel is fed continuously to the anode(negative electrode) compartment and the oxidant(i.e, oxygen from air) is fed continuously to the cathode(positive electrode) compartment; the electrochemical reactions take place at the electrodes to produce an electric current. Many of the operational characteristics of fuel cell systems are superior to those of conventional power generation system because of good efficiency, environmental protection, safty, modularity etc. From those reasons, the fuel cells are considered to be the solution to the future problem of energy conversion. The objective of this paper is to introduce the technical status of fuel cell technologies and our national project for the development of the phosporic acid fuel cell.

• The Journal of Korean Medicine
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• v.24 no.1
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• pp.190-201
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• 2003

Object : This study was designed to investigate the effects of Chungganhaeju-tang (Qingganjiejiu-tang) on cytotoxicity, growth inhibition, apoptosis and expression of cytokine in damaged HepG2 cells. Method : Toxicity on HepG2 cell induced by ethanol and acetaldehyde was measured for viability, cell growth, DNA replication and generation of apoptosis and cytokine. The recovery of the cell activity by Chungganhaeju-tang was estimated for the measured parameters using PCR with different cycle numbers, DNA gel-electrophoresis, and densitometric analysis, Results : Chungganhaeju-tang improves the recovery of HepG2 cells damaged by ethanol or acetaldehyde. The suppressed DNA synthesis of the cell damaged by ethanol or acetaldehyde is improved by Chungganhaeju-tang. A liver-protection effect was shown by the reduction of apoptosis and $TNF-{\alpha},{\;}IL-1{\beta}$ expressions that are induced by ethanol or acetaldehyde. Conclusion : The result indicates that Chungganhaeju-tang reduces toxicity induced by ethanol or acetaldehyde and recovers damaged liver function.

• Journal of Advanced Marine Engineering and Technology
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• v.31 no.8
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• pp.924-931
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• 2007

Now, there are two big issues threatening global society, which are the depletion of fossil fuels and the environmental disruption. Therefore, marine diesel engine, taking up over 95% share of the marine power market, has met the environmental and economical problems, too. These problems have caused a necessity of new, alternative power systems in ships and fuel cell systems has been playing a central role as one of the alternatives. This paper analyzes the characteristics of marine fuel cell systems, R&D trends of advanced countries, and mapping out R&D strategy of Korea.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1998.03a
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• pp.127-130
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• 1998

In this paper, we propose a method of cooperative control(T-cell modeling) and selection of group behavior strategy(B-cell modeling) based on immune system in distributed autonomous robotic system(DARS). Immune system is living body's self-protection and self-maintenance system. Thus these features can be applied to decision making of optimal swarm behavior in dynamically changing environment. For the purpose of applying immune system to DARS, a robot is regarded as a B cell, each environmental condition as an antigen, a behavior strategy as an antibody and control parameter as a T-call respectively. The executing process of proposed method is as follows. When the environmental condition changes, a robot selects an appropriate behavior strategy. And its behavior strategy is stimulated and suppressed by other robot using communication. Finally much stimulated strategy is adopted as a swarm behavior strategy. This control scheme is based of clonal selection and idiotopic network hypothesis. And it is used for decision making of optimal swarm strategy. By T-cell modeling, adaptation ability of robot is enhanced in dynamic environments.

• Journal of Microbiology and Biotechnology
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• v.7 no.6
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• pp.429-434
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• 1997

Macrolactin A, 24-membered macrolide, was isolated from the culture broth of Actinomadura sp. as a neuronal cell protecting substance. In the cell assay, this compound inhibited glutamate toxicity in N18-RE-105 cells with an $EC_50$ value of 0.5 ${\mu}g/ml.