• 한국미생물생명공학회:학술대회논문집
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• 한국미생물생명공학회 2000년도 Proceedings of 2000 KSAM International Symposium and Spring Meeting
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• pp.168-171
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• 2000

The thermal stability and catalytic activity of phospholipase A$_1$ from Serratia sp. MK1 were improved by an evolutionary molecular engineering. Two thermostable mutants were isolated after sequential rounds of error-prone PCR to introduce random mutations and filter-based screening of the resultant mutant library, and identified as having six (mutant TA3) and seven (mutant TA13) amino acid substitutions, respectively. Different types of the substitutions were found in two mutants, resulting in the increase of nonploar residues (mutant TA3) or changes between side chains within polar or charged residues (mutant TA13). The wild-type and mutant enzymes were purified, and the effect of temperature on their stability and catalytic activity was investigated. The T$\sub$m/ values of TA3 and TA13 were increased by 7 and 11$^{\circ}C$, respectively. Thus, evolutionary molecular engineering was found to be an effective and efficient approach to increasing thermostability without compromising enzyme activity.

• 한국지능시스템학회논문지
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• 제15권5호
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• pp.632-638
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• 2005

This paper describes a new data-handing, based on a Spatial Human Interface as human indicator, to the Spatial-Knowledge-Tags (SKT) in the spatial memory the Spatial Human Interface (SHI) is a new system that enables us to facilitate human activity in a working environment. The SHI stores human activity data as knowledge and activity history of human into the Spatial Memory in a working environment as three-dimensional space where one acts, and loads them with the Spatial-Knowledge-Tags(SKT) by supporting the enhancement of human activity. To realize this, the purpose of SHI is to construct new relationship among human and distributed networks computers and sensors that is based on intuitive and simultaneous interactions. In this paper, the specified functions of SKT and the realization method of SKT are explained. The utility of SKT is demonstrated in designing a robot motion control.

• KSBB Journal
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• 제13권1호
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• pp.38-43
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• 1998

Application of pervaporative extraction of ethanol to simultaneous saccharification and fermentation(SSF) of cellulose was investigated. From batch experiments, optimum cellulose substrate and enzyme loadings were found to be 10% and 15 IFPU/g cellulose, respectively. The cellulose conversion was lowered in fed-batch system due to the ethanol accumulation. The activity of the yeast Saccharomyces uvarum used in this study was significantly reduced at ethanol concentrations above around 40 g/L. From pervaporation experiments using PDMS membrane, ethanol was efficiently separated at 38$^\circ C$ and 10 mmHg of a down stream pressure. The pervaporation unit with 240 cm$^2$ of surface area was combined into the SSF reactor. The continuous removal of ethanol by pervaporation during SSF resulted in an improved cellulose conversion. Within the scope of this experiment, ethanol yields in the pervaporative SSF and simple SSF were 68.3% and 56.6%, respectively. The permeate flux for SSF broth pervaporation was about one-half that for the pervaporation of aqueous ethanol solution. Accordingly, the development of a membrane with higher ethanol selectivity and flux will increase the feasibility of this technology.

• 한국식품영양학회지
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• 제12권1호
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• pp.43-49
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• 1999

The effects of purine catabolites in growth media on the Serratia marcescens purine nucleoside phos-phorylase activity were examined. The enzyme activity was decreased above 60% by guanosine(5 to 15mM). The enzyme activity was not affected at low concentration of inosine (0.1∼1mM). The en-zyme activity was decreased approximately by 40∼50% in the presence of high concentrations of aden-osine hypoxanthine and xanthine (5∼15mM) but was not affected at low concentration of adenosine hypoxanthine and xanthine (0.1∼0.5mM). However the enzyme activity was increase by 20% with low concentrations of uric acid(0.5mN). but was decreased by 80% with high concentrations of same purine catabolite (15mM). Also the enxzyme activity was increased by 20% with low concentrations of glyoxylate (0.5mM) final degradative product of uric acid but was decreased by 30∼50% with high con-centrations of glyoxylate (3∼15mM). The enzyme activity was decreased approximately by 20% by the simultaneous addition of inosine hypoxanthine and uricacid at 5mM each whereas it was increased by 22 and 33% by the combination of inosine and uric acid three purine catabolites at 0.5mM respectively These data suggest that S. marcescens purine nucleoside phosphorylase is positively regulated by a glyox-ylate concentration and then may play a regulatory role in a purine catabolism.

• 생약학회지
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• 제44권4호
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• pp.362-367
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• 2013

Ojeok-san has been commonly used to treat low back pain disease. We performed the experiments on simultaneous analysis of 11 compounds and antioxidant effects of Ojeok-san. A HPLC method was established for simultaneous analysis of 11 compounds. The detection wavelengths were set at 230, 254, 280, 320, and 330 nm. The detected 11 compounds from Ojeok-san water extract showed good linearity($r^2{\geq}0.9997$). Limit of detection(LOD) and limit of quantification(LOQ) were 0.04-0.87 ${\mu}g/mL$ and 0.13-2.63 ${\mu}g/mL$, respectively. The antioxidant effects of Ojeok-san water extract were investigated by DPPH and ABTS assays. Ojeok-san water extract significantly increased the DPPH and ABTS radical scavenging effects in a dose-dependent manner. The $RC_{50}$ value of Ojeok-san on DPPH radical was 284.71 ${\mu}g/mL$ and that of ABTS radical was 96.16 ${\mu}g/mL$.

• 한국콘텐츠학회논문지
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• 제18권3호
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• pp.1-10
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• 2018

이 연구는 초고속 인터넷 환경에서 세계 최고 수준의 디지털 네이티브(digital native)세대를 형성하고 있는 한국적 현실에서 이들의 미디어 이용행태에 대한 종합적인 이해를 위해 시작됐으며, 미디어 동시이용행태에 대한 한국적 디지털 네이티브의 속성을 파악하고자 했다. 이를 위해 2015년도 <한국미디어패널> 데이터를 기반으로 디지털 네이티브 세대에 해당하는 10대 청소년들의 시간대에 따른 공간적 속성과 이용매체, 동시이용 형태 등에 대해 다중대응분석을 실시하였다. 연구결과 한국의 디지털 네이티브 세대라고 할 수 있는 10대 청소년의 경우, 시간적, 공간적 매체이용은 매우 균질한 형태를 띠고 있으며, 미디어 동시이용비율도 제한된 형태로 나타났다. 이 연구는 추후 다양한 세대 간 비교 연구를 통해 보다 총체적인 미디어 이용행태연구의 필요성을 제기하고 있다.

• 대한한의학회지
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• 제32권3호
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• pp.25-34
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• 2011

Objectives: We performed simultaneous determination of five constituents by HPLC in Samul-tang (SMT). Additionally, we investigated the immune-stimulatory potential of SMT on specific cellular and humoral immune responses in ovalbumin (OVA)-immunized mice. Methods: Reverse-phase chromatography using a Gemini C18 column operating at $40^{\circ}C$, and photodiode array (PDA) detection at 190-400 nm, were used for quantification of the five components of SMT. Mobile phase using a gradient flow consisted of two solvent systems. Solvent A was 1.0% (v/v) aqueous acetic acid and solvent B was acetonitrile with 1.0% (v/v) acetic acid. C57BL/6 mice were immunized intraperitoneally with OVA/alum ($100{\mu}g/200{\mu}g$) on days 1, 8, and 15. The extract of SMT (1000 mg/kg) was given to mice orally for 21 days (from day 1 to day 21). At day 22, OVA-, lipopolysaccharide (LPS)- and concanavalin A (Con A)-stimulated splenocyte proliferation and OVA-specific and total antibodies were measured in plasma. Results: Calibration curves were acquired with $r^2$>0.9999, and the relative standard deviation (RSD, %) for intra- and inter-day precision were both less than 3.5%. The recovery was in the range of 95.69-115.12%, with an RSD less than 6.0%. The contents of five components in SMT were 1.08-15.30 mg/g. SMT significantly enhanced Con A-induced splenocyte proliferation in OVA-immunized mice (p<0.01). Also, SMT significantly enhanced OVAspecific IgG, IgG1 and total IgM levels in plasma compared with the OVA-immunized group. Conclusions: The established method will be applied for the quantification of major components and immunestimulating activity in OVA-immunized mouse model of SMT.

• 공업화학
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• 제23권3호
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• pp.253-258
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• 2012

본 연구는 $Pd/TiO_2$ 촉매를 이용한 $CH_4$, CO 동시 산화반응에서 활성점 및 Pd의 산화 상태에 대한 영향을 조사하였다. Pd 함량이 증가할수록 Pd 종(PdO)의 결정성장을 야기시켜 $CH_4$ 산화반응 활성을 증진시켰다. 열처리를 통해 제조된 촉매표면의 Pd 산화상태에 따라 $CH_4$과 CO의 산화반응 활성이 상이한 결과를 나타내었다. XRD와 $H_2-TPR$ 분석으로 소성촉매는 $Pd^{2+}$종, 환원촉매는 $Pd^0$종이 우점하고 있음을 확인하였다. 또한, BET분석을 통해 촉매 활성인자인 비표면적 및 기공부피보다는 Pd의 산화상태가 촉매 활성에 미치는 중요한 인자임을 알 수 있었다. FT-IR 분석을 이용하여 Pd의 산화상태에 따른 $CH_4$과 CO의 반응 메커니즘을 확인할 수 있었다.

• 한국대기환경학회지
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• 제14권1호
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• pp.63-72
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• 1998

Simultaneous CO and $C_3H_6$ oxidation was carried out over noble metal supported monolith catalysts in a flow thorugh type reactor at the temperature ranging from room temperature to $500^\circ$C. Pt and Pd were selected as major active species, 10wt% of Ce was impregnated as an additive and alumina and silica were used as supports. The reactant gases were simulated and the reaction products were analyzed by on-line G.C.. EDX, SEM, TGA, XRD and optical microscope were used to analyze the characteristics of the prepared catalysts. Under the given conditions in this study, the catalysts supported on alumina showed better activity for CO oxidation, while Pd catalysts showed better activity for $C_3H_6$ oxidation. The improvement of conversion due to increase in thermal stability possibily by Ce addition was observed only for Pt catalysts.

• IMMUNE NETWORK
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• 제9권6호
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• pp.243-247
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• 2009

In this study, we report the development of a new dual reporter vector system for the analysis of promoter activity. This system employs green fluorescence emitting protein, EGFP, as a reporter, and uses red fluorescence emitting protein, DsRed, as a transfection control in a single vector. The expression of those two proteins can be readily detected via flow cytometry in a single analysis, with no need for any further manipulation after transfection. As this system allows for the simultaneous detection of both the control and reporter proteins in the same cells, only transfected cells which express the control protein, DsRed, can be subjected to promoter activity analysis, via the gating out of all un-transfected cells. This results in a dramatic increase in the promoter activity detection sensitivity. This novel reporter vector system should prove to be a simple and efficient method for the analysis of promoter activity.