• Journal of Microbiology and Biotechnology
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• 제25권4호
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• pp.459-463
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• 2015

This study evaluated the microbial conversion of coconut oil waste, a major agro-residue in tropical countries, into single cell oil (SCO) feedstock for biodiesel production. Copra cake was used as a low-cost renewable substrate without any prior chemical or enzymatic pretreatment for submerged growth of an oleaginous tropical mangrove fungus, Aspergillus terreus IBB M1. The SCO extracted from fermented biomass was converted into fatty acid methyl esters (FAMEs) by transesterification and evaluated on the basis of fatty acid profiles and key fuel properties for biodiesel. The fungus produced a biomass (8.2 g/l) yielding 257 mg/g copra cake SCO with ~98% FAMEs. The FAMEs were mainly composed of saturated methyl esters (61.2%) of medium-chain fatty acids (C12-C18) with methyl oleate (C18:1; 16.57%) and methyl linoleate (C18:2; 19.97%) making up the unsaturated content. A higher content of both saturated FAMEs and methyl oleate along with the absence of polyunsaturated FAMEs with ≥4 double bonds is expected to impart good fuel quality. This was evident from the predicted and experimentally determined key fuel properties of FAMEs (density, kinematic viscosity, iodine value, acid number, cetane number), which were in accordance with the international (ASTM D6751, EN 14214) and national (IS 15607) biodiesel standards, suggesting their suitability as a biodiesel fuel. The low cost, renewable nature, and easy availability of copra cake, its conversion into SCO without any thermochemical pretreatment, and pelleted fungal growth facilitating easier downstream processing by simple filtration make this process cost effective and environmentally favorable.

• 대한본초학회지
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• 제35권5호
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• pp.33-39
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• 2020

Objectives : Increasing evidence supports the biological and pharmacological activities of essential oils on the central nervous system such as pain, anxiety, attention, arousal, relaxation, sedation and learning and memory. The purpose of present work is to investigate the protective effect and molecular mechanism of cypress essential oil (CEO) against scopolamine (SCO)-induced cognitive impairments in C57BL/6 mice. Methods : A series of behavior tests such as Morris water maze, passive avoidance, and fear conditioning tests were conducted to monitor learning and memory functions. Immunoblotting and RT-PCR were also performed in the hippocampal tissue to determine the underlying mechanism of CEO. Results : SCO induced cognitive impairments as assessed by decreased step-through latency in passive avoidance test, relatively low freezing time in fear conditioning test, and increased time spent to find the hidden platform in Morris water maze test. Conversely, CEO inhalation significantly reversed the SCO-induced cognitive impairments in C57BL/6 mice comparable to control levels. To elucidate the molecular mechanisms of memory enhancing effect of CEO we have examined the expression of brain-derived neurotrophic factor (BDNF) in the hippocampus. CEO effectively elevated the protein as well as mRNA expression of BDNF via activation of cAMP response element binding protein (CREB). Conclusions : Our findings suggest that CEO inhalation effectively restored the SCO-impaired cognitive functions in C56BL/6 mice. This learning and memory enhancing effect of CEO was partly mediated by up-regulation of BDNF via activation of CREB.

• 청정기술
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• 제18권1호
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• pp.89-94
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• 2012

본 연구에서는 산성을 갖는 Fe-ZSM5를 담체로 활용하여 Pd, Pt 등 귀금속을 담지한 후, 제조 촉매의 암모니아의 선택적 산화반응 활성을 평가하였다. 이들 중 Pt/Fe-ZSM5가 Pd/Fe-ZSM5 보다 높은 활성을 나타냈다. 또한 Pt/Fe-ZSM5 촉매에서 ZSM5 구조체 내 Fe의 이온교환량을 달리한 촉매의 실험을 수행하여, 암모니아의 선택적 산화반응에 가장 우수한 활성을 보이는 최적 조성비를 탐색하였다. 그 결과, Fe의 이온교환량이 적을수록 반응 활성이 증가하는 경향을 보였고, 저온 영역인 $250^{\circ}C$에서 100%의 암모니아 전환율을 나타냈다. 이와 같이 암모니아의 선택적 산화반응에 효과적인 Fe-ZSM5 담체에 대하여, ICP-AES, BET, XRD, $NH_3$-TPD 등과 같은 특성 분석을 수행하여 제조 촉매의 구조와 물성이 반응활성에 미치는 영향을 검토해보았다.

• 한국분말재료학회지
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• 제26권5호
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• pp.410-414
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• 2019

The hydrogen reduction behavior of the $CuO-SCo_3O_4$ powder mixture for the synthesis of the homogeneous Cu-15at%Co composite powder has been investigated. The composite powder is prepared by ball milling the oxide powders, followed by a hydrogen reduction process. The reduction behavior of the ball-milled powder mixture is analyzed by X-ray diffraction (XRD) and temperature-programmed reduction at different heating rates in an Ar-10%H2 atmosphere. The scanning electron microscopy and XRD results reveal that the hydrogen-reduced powder mixture is composed of fine agglomerates of nanosized Cu and Co particles. The hydrogen reduction kinetics is studied by determining the degree of peak shift as a function of the heating rate. The activation energies for the reduction of the oxide powders estimated from the slopes of the Kissinger plots are 58.1 kJ/mol and 65.8 kJ/mol, depending on the reduction reaction: CuO to Cu and $SCo_3O_4$ to Co, respectively. The measured temperature and activation energy for the reduction of $SCo_3O_4$ are explained on the basis of the effect of pre-reduced Cu particles.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2011년도 제37회 추계학술대회논문집
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• pp.352-358
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• 2011

본 논문은 우발적 화재에 노출되면 이상 온도를 감지하고, 자동으로 반응하여 추진제를 연소시킴으로써, 고체 추진기관의 위험 정도를 완화시키는 둔감 점화 장치의 반응을 연구한 결과이다. Kissinger 식으로 구한 둔감 점화 장치 신호 화약의 자동 점화 온도는 $165.5^{\circ}C$이었지만, 추진기관에 장착하고 MIL-STD-2105D의 규정에 따라 수행한 완속 가열 시험에서는 약 $140^{\circ}C$에서 연소 반응을 하였다.

• KSBB Journal
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• 제26권6호
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• pp.523-528
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• 2011

The objective of this study was to reduce negative elements such as volatile organic compounds (VOCs) from fulvic acid using supercritical carbon dioxide ($SCO_2$) and to measure concentration and chromaticity of fulvic acid before and after treatment of $SCO_2$. Fulvic acid was treated at different experimental conditions; pressures of 100, 120 and 150 bar at $40^{\circ}C$ for 2 h. The composition of VOCs from fulvic acid was evaluated by GC-MS analysis, and the concentration was quantitatively analyzed using UV-spectrometer from fulvic acid at different experimental conditions. Also, the chromaticity of fulvic acid was evaluated using spectrophotometer. Though concentration and chromaticity of fulvic acid were not nearly changed, the VOCs from fulvic acid was remarkably decreased at 150 bar, $40^{\circ}C$ and 2 h. Reduction of VOCs through the $SCO_2$ is expected to contribute to quality improvement of fulvic acid.

• 한국수산과학회지
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• 제45권3호
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• pp.201-206
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• 2012

Supercritical carbon dioxide ($SCO_2$) extraction was used to recover concentrated proteins and to remove lipids and odor causing compounds from anchovy. Engraulis japonicus $SCO_2$ was used as the solvent for extraction, which was performed in a semi-batch flow reactor. The experimental conditions used were pressure, 15-25 MPa; temperature, $40-60^{\circ}C$ and sample size, 500 ${\mu}m$. The proteins obtained under these conditions performed well in a sensory evaluation; moreover, effective lipids and odor removal was achieved. The stability and characteristics of the proteins recovered with different solvents were also evaluated. The samples were sterilized by processing with $SCO_2$. Escherichia coli was not detected after storage for several days. The sensory characteristics were found to be superior to those of a sample produced by hexane extraction. Thus, the protein concentrate was obtained at $60^{\circ}C$ and 25 MPa was deemed valuable as a foodstuff.

• 한국식품과학회지
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• 제40권1호
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• pp.96-100
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• 2008

향신성 식용유는 에너지원이나 대사조절물질로서뿐 아니라 식품의 맛이나 향 또는 포만감을 결정하는 지방이다. 본 연구는 0.12% 콜레스테롤 식이를 한 흰쥐에서 대두유를 대조로 하여 향신성 식용유(고추종실유, 산초유)에 의한 지질농도의 조절효과를 평가하였다. 사료중 n-6/n-3 지방산의 비는 8.8:1.2:70.1 (대두유:산초유:고추종실유)로 큰 차이가 있었다. 혈청콜레스테롤 농도는 고추종실유 섭취군에서 다른 군보다 높았으나, HDL-cholesterol/totalcholesterol 비는 고추종실유 섭취군에서 낮았다. 혈청중성지질 농도는 다른 군에 비하여 산초유 섭취군에서 낮았다. 반면에 간장 콜레스테롤 농도는 고추종실유 섭취군보다 산초유 섭취군에서 높았다. 이러한 응답은 식이지방에 의한 혈청 콜레스테롤 농도의 응답은 조직간 콜레스테롤 분배의 차이에 기인되는 듯하다. 결론적으로 본 연구는 콜레스테롤 함유식이를 한 흰쥐에서 고추종실유는 대두유에 비하여 콜레스테롤상승효과를 보여준 반면, 산초유는 중간적 효과를 보여주었다.

• KSBB Journal
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• 제24권3호
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• pp.259-266
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• 2009

AfsR2 과발현 S. lividans TK21을 이용하여 DNA microarray를 수행하였다. 그 결과, phosphate starvation과 관련 있는 42개의 유전자들이 up-regulated 되었으며, 특히 SCO4139 (pstB, phosphate ABC transport system ATP-binding protein)와 SCO4142 (pstS, phosphate-binding protein precursor)는 afsR2가 phosphate와 같은 nutrient starvation에 적극적으로 관여한다는 것을 나타내며, SCO4228 (putative phosphate transport system regulatory protein)은 기존에 수행되었던 2D-electrophoresis 연구나 afsS null S. coelicolor를 이용한 DNA microarray 연구에서도 공통적으로 보고되었던 유전자로서 phosphate lilitation에 대한 afsR2의 효과가 지속적으로 검증되고 있음을 뜻한다. 또한 afsR2 과발현을 통해서 sigma factor인 SCO2954 (sigL)과 SCO5147 (sigE)의 발현이 유도되었으며 두 유전자의 구조적인 특징을 고려해 보았을 때 afsR2가 RNA polymerase와의 linker로서의 역할을 추측해 볼 수 있다. 뿐만 아니라 whi 관련 유전자들의 발현 또한 afsR2에 의해 증가되었다. 이는 afsR2가 단순히 2차 대사물질 생합성 조절에만 관여하는 것이 아니라 형태적 분화에 작용함으로써 최종적으로 여러 2차 대사물질의 합성을 유도한다고 말할 수 있다. 이러한 결과들을 토대로 afsR2가 기존에 항생제 생합성에만 관여하는 global regulatory 조절인자가 아닌 방선균이 stationary phase로 전환되는 시점에서 형태적 분화에 영향을 미치고 phosphate limitation stress를 줄여주는 2차 대사의 key-factor regulatory 유전자임을 알 수 있다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 추계종합학술대회 논문집(1)
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• pp.57-60
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• 2000

본 논문은 블루투스 헤드셋의 구현에 대해 기술한다. 블루투스 헤드셋은 ACL 연결을 통하여 헤드셋과 오디오 게이트웨이 사이의 link를 선정하고, SCO 연결을 통하여 64kbps의 음성을 전송한다. 본 논문에서 구현한 블루투스 헤드셋은 HCI가 없는 구조로 설계되어 블루투스 모듈내에 모든 프로토콜 스택이 구현되었고, 헤드셋에 구현된 상위 프로토콜 및 응용 프로그램에 대해서 Unix 환경에서 C-language modeling을 통하여 검증하였다.