• KSBB Journal
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• 제13권4호
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• pp.369-377
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• 1998

To analyze the unique aspects of biomolecular processing for monoclonal antibody (MAb) production and secretion, the simple working model based on 3-compartment (endoplasmic reticulum, Golgi apparatus, and extracellular medium) was developed. Based on in vitro MAb assembly experimental results, the kinetic model for MAb assembly in the endoplasmic reticulumn was proposed. The dynamics of MAb assembly and secretion was simulated using methematica program. According to the simulation results, the proposed 3-compartment model provides an efficient means to predict the specific MAb productivity as well as intracompartmental concentrations of MAb in endoplasmic reticulum, Golgi apparatus, and extracellular compartment model. In vivo profiles of MAb intermediates gave good agreements with the simulation profiles predicted by the intracellular compartment model. Furthermore, results of such analysis can help in directing the control strategy for optimum biomolecular processing in a mammalian cell culture system.

• Korea-Australia Rheology Journal
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• 제18권4호
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• pp.191-197
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• 2006

The measurement of the compressional rheological parameters for an aggregated particulate suspension is described. The parameters include the compressive yield stress and hindered settling function, describing the extent and rate of dewatering respectively. The variation of these parameters with shear rate and time of shear is also considered in the light of their sensitivity to low shear rates, with particular reference to the case of flocculated particulate suspensions. The latter is seen to be important in the future development of a comprehensive understanding of compressive rheology of aggregated particulate suspensions in industrial applications such as thickening, filtration and centrifugation.

• Korea-Australia Rheology Journal
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• 제20권4호
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• pp.235-243
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• 2008

The aim of this study is to explore the possibility of incorporating supercritical carbon dioxide ($scCO_2$) into twin screw extrusion process for the production of polypropylene-clay nanocomposite (PPCN). The $CO_2$ is used as a reversible plasticizer which is expected to rapidly transport polymeric chains into the galleries of clay layers in its supercritical condition inside the extruder barrel and to expand the gallery spacings in its sub-critical state upon emerging from die. The structure and properties of the resulting PPCNs are characterized using wide-angle X-ray diffraction (WAXD), transmission electron microscopy (TEM), rheometry, thermogravimetry and mechanical testing. In the processing of the PPCNs with $scCO_2$, optimum $scCO_2$ concentration and screw speed which maximized the degree of intercalation of clay layers were observed. The WAXD result reveals that the PP/PP-g-MA/clay system treated with $scCO_2$ has more exfoliated structure than that without $scCO_2$ treatment, which is supported by TEM result. $scCO_2$ processing enhanced the thermal stability of PPCN hybrids. From the measurement of linear viscoelastic property, a solid-like behavior at low frequency was observed for the PPCNs with high concentration of PP-g-MA. The use of $scCO_2$ generally increased Young's modulus and tensile strength of PPCN hybrids.

• KSBB Journal
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• 제31권4호
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• pp.246-255
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• 2016

Co-production of 3-hydroxypropionic acid (3-HP) and 1,3-propanediol (1,3-PDO) was suggested as an innovative strategy to overcome several limitations occurring in the single production of 3-HP from glycerol. In this study, two new isolates of Klebsiella pneumoniae, which produce less lipopolysaccharide (LPS) thus considered less pathogenic than K. pneumoniae DSM 2026, were compared and evaluated for their potential for the co-production of 3-HP and 1,3-PDO. The newly isolated strains showed significantly faster sedimentation rate than DSM, which should be beneficial for downstream processing. Analysis of genome sequences of the isolates confirmed the presence of all genes necessary for glycerol assimilation, 1,3-PDO production and biosynthesis of coenzyme $B_{12}$. Co-production yield was highest under anaerobic condition while cell growth was highest under aerobic condition. Both strains showed similarly good performance for the co-production although J2B gave the slightly higher co-production yield of 0.80 mol/mol than GSC021 (0.75 mol/mol). The evaluation of the newly developed strains presented here should be useful in designing similar evaluation experiments for other microorganisms.

• 한국정보과학회논문지:소프트웨어및응용
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• 제34권12호
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• pp.1056-1064
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• 2007

생체분자 컴퓨팅은 DNA와 같은 생체 분자를 이용하여 정보를 표현하고 처리하는 새로운 컴퓨팅 패러다임이다. 작은 부피에 존재하는 무수히 많은 분자와 화학 반응에 내재된 대규모 병렬성은 새로운 개념의 고성능 계산 기법에 영감을 주었고 이를 바탕으로 다양한 계산 모델 및 문제 해결을 위한 분자알고리즘이 개발되었다. 한편 생체 분자를 이용한 정보처리라는 특징은 생물학 문제에 적용될 수 있는 가능성을 시사한다. 유전자 발현 패턴과 같은 생화학적 분자 정보의 분석을 위한 도구로서의 가능성을 가지고 있는 것이다. 이러한 맥락에서 DNA 컴퓨팅 기반의 생체분자 퍼셉트론 모델이 제안되었고 그 실험적 구현 결과가 제시된 바 있다. 생체분자 퍼셉트론의 핵심인 가중치 표현 및 가중치-합 연산은 입력 분자와 가중치를 표현하는 프로브 분자간의 경쟁적 혼성화 반응에 기반하고 있다. 그러나 그 혼성화 반응에서 열역학적 대칭성을 가정하고 있기 때문에 사용하는 프로브에 따라 가중치 표현의 오차가 있을 수 있다. 본 논문에서는 비대칭적인 열역학적 특성을 고려하여 일반화된 혼성화 반응 모델을 제시하고, 이를 바탕으로 신뢰성 있는 생체 분자 퍼셉트론의 구현을 위한 가중치 코딩 방법을 제안한다. 그리고 본 논문에서 제시한 가중치 표현 방법의 정확성을 이전 모델과 컴퓨터 시뮬레이션을 통해 비교하고 한계 오차를 만족하기 위한 조건을 제시한다.

• Journal of Microbiology and Biotechnology
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• 제34권5호
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• pp.987-993
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• 2024

Campylobacteriosis is a significant foodborne illness caused by Campylobacter bacteria. It is one of the most common bacterial causes of gastroenteritis worldwide, with poultry being a major reservoir and source of infection in humans. In poultry farms, Campylobacters colonize the intestinal tract of chickens and contaminate meat during processing. Vaccines under development against Campylobacters in poultry showed partial or no protection against their cecal colonization. Therefore, this review will elaborate on campylobacteriosis and emphasize the control strategies and recent vaccine trials against Campylobacters in poultry farms. The epidemiology, diagnosis, and treatment of Campylobacter infection, along with specific mention of poultry Campylobacter contamination events in Malaysia, will also be discussed.

• Korea-Australia Rheology Journal
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• 제20권2호
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• pp.51-58
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• 2008

This paper describes a two-step Tikhonov regularization procedure for converting the steady shear data generated by parallel-disk viscometers, in the presence of wall slip, into a shear stress-shear rate function and a wall shear stress-slip velocity functions. If the material under test has a yield stress or a critical wall shear stress below which no slip is observed the method will also provide an estimate of these stresses. Amplification of measurement noise is kept under control by the introduction of two separate regularization parameters and Generalized Cross Validation is used to guide the selection of these parameters. The performance of this procedure is demonstrated by applying it to the parallel disk data of an oil-in-water emulsion, of a foam and of a mayonnaise.

• Korea-Australia Rheology Journal
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• 제19권1호
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• pp.1-5
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• 2007

By combining ultrasonic energy which is essential for the chain scission of polymer molecules and a multifunctional agent (MFA) having double bonds at its ends, we were able to modify the molecular structure of polycarbonate (PC) from linear to a branched structure during melt processing. The three double bonds in chain ends of MFA were expected to act as sites for trapping macroradicals of PC during the course of ultrasound-assisted mixing process. The transformation of molecular structure of PC was confirmed by the measurements of rheological properties of the modified PC. After the ultrasonic irradiation of PC together with MFA, increase in complex viscosities and shear-thinning behavior were observed. The Cole-Cole plot and measurement of extensional viscosities revealed the characteristic features of branched structure with well-defined extensional behavior which is comparable to that of a commercial branched PC.

• 공업화학
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• 제26권6호
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• pp.640-647
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• 2015

투명 전극의 응용분야가 확대되고 시장의 규모가 커짐에 따라 기존 투명 전극 재료인 ITO (Indium Tin Oxide)를 대체할 차세대 투명전극의 개발에 관심이 집중되고 있다. 다양한 후보군 중에서도 대표적인 전도성 고분자인 PEDOT : PSS [poly(3,4-ethylenedioxythiophene) : poly(styrene sulfonate)]는 기계적 유연성을 갖고 있으면서도 소재와 공정 상의 가격 경쟁력이 크기 때문에 미래 소자 구현을 위한 투명전극 재료로 주목을 받고 있으며, 현재 PEDOT : PSS의 전기전도도 수준을 ITO나 금속의 수준으로 향상시키기 위해 다양한 화학적/물리적 처리를 통한 기능성 향상에 많은 연구가 진행 중이다. 본 총설에서는 전도성 고분자의 전기 전도도를 향상시키기 위한 다양한 공정 기술에 대한 연구 현황을 짚어보고자 한다. 대표적으로 유기용매, 이온성 액체, 계면활성제 등과 같은 첨가제와 박막에 대한 산 처리 공정, 물리적 인장을 통한 전기전도도 향상 연구를 들 수 있다. 또한 이러한 공정을 적용하여 전도성 고분자 투명 전극을 전자 및 에너지 소자에 응용한 사례도 간략히 소개하고자 한다.

• Journal of Microbiology
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• 제43권3호
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• pp.295-300
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• 2005

In the present study, the performances of conventional purification methods, packed bed adsorption (PBA), and expanded bed adsorption (EBA) for the purification of the nucleocapsid protein (NP) of Newcastle disease virus (NDV) from Escherichia coli homogenates were evaluated. The conventional methods for the recovery of NP proteins involved multiple steps, such as centrifugation, precipitation, dialysis, and sucrose gradient ultracentrifugation. For the PBA, clarified feedstock was used for column loading, while in EBA, unclarified feedstock was used. Streamline chelating immobilized with $Ni^{2+}$ ion was used as an affinity ligand for both PBA and EBA. The final protein yield obtained in conventional and PBA methods was $1.26\%$ and $5.56\%$, respectively. It was demonstrated that EBA achieved the highest final protein yield of $9.6\%$ with a purification factor of 7. Additionally, the total processing time of the EBA process has been shortened by 8 times compared to that of the conventional method.