• Mass Spectrometry Letters
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• 제10권2호
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• pp.66-70
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• 2019

Rivaroxaban (RRN) is the first available active direct factor Xa inhibitor (anticoagulant) with oral administration. Due to its success in market, there have been efforts to develop various RRN formulations, and the development of good analytical methods for its in vivo evaluation is an essential prerequisite. Thus, here, a simple and efficient method to determine RRN in rat plasma using liquid-liquid extraction (LLE) and liquid chromatography and multiple reaction monitoring (LC-MRM) was presented. The use of ethyl acetate as the LLE solvent results appropriate extraction and purification of RRN and it also helps the significant reduction of rat plasma volume required for RRN quantitation. The developed method showed good analytical performance including specificity, linearity ($r^2{\geq}0.999$ within 0.5 - 500 ng/mL), sensitivity (the lower limit of quantitation at 0.5 ng/mL), accuracy (89.3 - 107.0%), precision (${\geq}12.7%$), and recovery (89.2 - 105.7%). Additionally, RRN in sample extracts showed good stability. Finally, the applicability of the validated method to the PK evaluation of RRN was confirmed after its oral administration to normal rats. The present method is the first analytical method employing LLE for the simple and efficient extraction and purification of RRN in rat plasma. Therefore, the present method can contribute to the development of new RRN formulations as well as to the monitoring of RRN in special clinical situations through its efficient determination in various samples with or without minor modification.

• Journal of Microbiology
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• 제45권6호
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• pp.593-596
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• 2007

In this study, we describe the development of a simple and efficient method for cell lysis via the insertion of a bacteriophage lambda lysis gene cluster into the pET22b expression vector in the following order; the T7 promoter, a gene for a target protein intended for production, Sam7 and R. This insertion of R and Sam7 into pET22b exerted no detrimental effects on cellular growth or the production of a target protein. The induction of the T7 promoter did not in itself result in the autolysis of cells in culture but the harvested cells were readily broken by freezing and thawing. We compared the efficiency of the cell lysis technique by freezing and thawing to that observed with sonication, and determined that both methods completely disintegrated the cells and released proteins into the solution. With our modification of pET22b, the lysis of cells became quite simple, efficient, and reliable. This strategy may prove useful for a broad variety of applications, particularly in experiments requiring extensive cell breakage, including library screening and culture condition exploration, in addition to protein purification.

• Biotechnology and Bioprocess Engineering:BBE
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• 제3권2호
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• pp.82-86
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• 1998

The maltose binding protein (MBP) fusion protein system is a versatile tool to express and isolate recombinant proteins in E. coli. In this system, MBP fusion proteins are efficiently isolated from whole cell lysate using amylose conjugated agarose beads and then eluted by competition with free maltose. Since MBP is a rather large molecule (∼42 kDa), for further experiments, the MBP part is usually proteolytically cleaved from the fusion protein and subsequently removed by ion-exchange chromatography or rebinding to amylose columns after washing out excess and MBP-bound maltose. In the present study, we have developed an improved method for the removal of cleaved MBP, which is advantageous over conventional methods. In this method, factor Xa cleaved MBP fusion proteins were incubated with Sepharose beads conjugated with MBP specific monoclonal antibodies and then precipitated buy centrifugation, resulting in highly purified proteins in the supernatant.

• Archives of Plastic Surgery
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• 제33권1호
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• pp.21-30
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• 2006

Alginate, a polymer of guluronic and mannuronic acid, is used as a scaffolding material in biomedical applications. The research was to produce highly-purified alginate from seaweeds and to evaluate the efficacy of alginate as dermal substrate. Our alginate purification method showed a production rate as high as 25%. The purified alginate contained little polyphenol contents and endotoxin, proteins. For study of wound healing, full thickness skin defects were made on the dorsal area of the animal models. And then alginate, fibroblast-growth-factor mixed alginate, alginate-collagen complex, vaseline gauze as control were applied on the wound, respectively, and were evaluated grossly and histopathologically. For biocompatibility test, alginate and alginate-collagen complex discs were implanted on the back of Sprague-Dawly rats. Four weeks after implantation, the animals were examined immunologically against alginate and collagen. Alginate and FGF-mixed alginate, alginate-collagen complex group showed statistically higher percentage of wound contraction and wound healing than control group(p<0.05). Alginate-collagen complex group and FGF-mixed alginate group showed statistically higher percentage of wound healing than alginate group. The experiment of biocompatibility and immunologic reaction against impanted alginate or collagen needs more investigation. Highly-purified alginate from seaweeds by our purification method, showed the effect of wound healing, and addition of FGF or collagen increases the alginate's wound healing effect. It shows the possibility of alginate as a dermal substrate.

• 생명과학회지
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• 제6권1호
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• pp.14-26
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• 1996

In order to effectively utilize fish(Cod, Gadus macrocephalus) bone obtained as fish waste in fish manufactory, the preparation of the fish bone gelatin were attempted by heat extracting method from collagen protein contained in the fish bone. The methods of two kinds pretreatments (the B-type by alkali pretreatment and the E-type by enzyme pretreatment) for fish bone and the optimal extraction conditions to prepare gelatin from pretreated fish bone were investigated. Physical properties and functionalities of the two type fish bone gelatins obtained were compared with the commercial gelatin and the fish skin gelatin. The optimal extraction conditions of the B-type and the E-type gelatins were 5 folds of added water with material(w/w), pH 5.0, 3 hrs of extraction time and 60$\circ$C of extraction temperature. The yield of the B-type and the E-type gelatins were 32.6% and 28.1 %, respectively. The B-type gelatin was superior to the E-type un all physical properties. Molecular weight of the B-type was larger than that of the E-type due to its pretreatment method. Among the composition of amino acids, the amino acids such as glycine, alanine, glutamic acid and imino acids(proline and hydroxyproline) were responsible for 68$\sim$70% of the total amino acids. Functionalities of the fish bone gelatin were almost similar to commercial gelatin.

• International Journal of Automotive Technology
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• 제7권3호
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• pp.277-282
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• 2006

With the aim of achieving half the regulated value of EURO-3 Emission Regulations, an ultra low emission motorcycle has been developed based on a motorcycle with an 1800 $cm^3$, horizontal opposed 6-cylinder engine. For the fuel supply system, an electronically controlled fuel injection system was applied. For the emission purification system, three-way catalysts, a feedback control system with a LAF(Linear Air-Fuel ratio) sensor, and a secondary air induction system were applied. To reduce CO and HC emissions during cold starting, an early catalyst activation method combining RACV(Rotary Air Control Valve) and retarded ignition timing was applied. After the catalyst activation, air-fuel ratio was controlled to maximize the purification ratio of the catalyst according to vehicle speed. For the air-fuel ratio control system, the LAF sensor was used. Furthermore, fine adjustment by the LAF feedback control reduced torque fluctuation due to the air-fuel ratio change. As a result, smooth ride feeling was maintained. Owing to these technologies, half the regulated value of EURO-3 has been achieved without any negative impact to the large-scaled motorcycles' drivability. This paper presents the developed ultra low emission technologies including the control method using an LAF sensor.

• 분석과학
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• 제24권6호
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• pp.477-483
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• 2011

본 연구는 supercapacitor에 사용되는 전해액인 이온성 액체 EMI-$BF_4$ (1-ethyl-3-methyl imidazolium tetrafluoroborate)를 제조 한 다음 산화알루미늄과 활성탄 그리고 액체/액체 연속 추출방법을 이용하여 고순도의 이온성 액체를 얻기 위한 정제방법을 연구하였다. 산화알루미늄과 활성탄을 이용한 정제는 고순도 이온성 액체를 얻기에는 부적합 하였고 액체/액체 연속 추출을 통한 정제과정에서 용매제의 변화에 따른 전기적 용량을 비교한 결과 이온성 액체 대비 증류수 비율을 높게 할수록 불순물제거율이 높으며 또한 supercapacitor의 전기적 성능이 좋게 나왔다. 그리고 추출용매는 1,2-dichloroethane을 이용할 경우 methylene chloride으로 추출할 때 보다 고순도의 이온성 액체를 얻었으며 또한 전기적 용량이 높게 나왔다.

• KSBB Journal
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• 제14권1호
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• pp.9-16
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• 1999

Transforming growth factor $\beta$1(TGF-$\beta$1)은 여러 가지 생물학적 활성을 가지는 관계로 의학적 치료제로서 사용될 가능성이 크다. 본 연구에서는 혈소판추출, 젤여과, 양이온교환 크로마토그래피 및 역상 HPLC등 네 단계의 정제과정으로 이루어져 있는 정제공정을 이용한 TGF-$\beta$1을 값싸고 효울적으로 정제하였다. 이 과정을 거쳐 최종적으로 얻어진 TGF-$\beta$1은 비환원조건하에서 SDS-PAGE를 행한 결과 구매된 TGF-$\beta$1 표준품과 일치한 위치에서 한 개의 band가 관찰되어 순수하다는 것을 확인하였으며 또한 이것이 Westem blot를 통하여 TGF-$\beta$1 항체와 결합하는 것으로부터 TGF-$\beta$1임을 확인하였다 또한, mink lung epithelial cell line 을 이용한 성장저해 실험을 통해 정제된 TGF-$\beta$1이 구매되TGF-$\beta$1 표준품보다 조금 높은 활성을 가지는 것을 확인하였다 최종적으로 농축혈소판 10단위로부터 약 3.7$\mu$g의 정제된 TGF-$\beta$1이 얻어져 그 최종수율은 약 21%였다.

• Journal of Radiation Protection and Research
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• 제24권2호
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• pp.73-86
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• 1999

현재 경수로형 원자력발전소의 일차계통 냉각수 정화를 위해 사용되는 이온교환방법은 제염효과가 우수하고 공정이 단순하며 조작이 간편하기 때문에 광범위하게 활용되고 있으나 비금속성분도 함께 제거하여 수지의 수명이 단축되고 폐이온교환수지가 발생되는 단점이 있다. 본 연구에서는 일차계통 냉각수 정화를 위해 사용되는 이온교환수지의 대체공정으로서 전기투석과 이온교환이 결합된 전기탈이온법의 사용가능성을 조사하기 위해 모의 용액을 이용하여 다양한 실험조건하에서 수행하였다. 실험결과 유입유량이 증가할수록 제거율은 증가하고 전력소모는 감소하였다. 금속성분 제거율에서 제염계수 1000으로 일정한 경향을 나타내었으며 전력소모 면에서는 TDS 3 ppm이하를 기준으로 유입유량이 $2.0{\ell}/min$일 때 $40.3mWh/{\ell}$ 이었다. 유입유속이 동일한 조건에서는 희석실에 채운 이온 교환수지의 함량이 증가할수록 금속성분 제거율과 전력소모에서 효과적인 것으로 평가되었다. 이온 교환수지를 채운 전기탈이온 공정은 이온교환수지 자체에 의한 수리적 저항과 현탁질에 의한 수지의 오염으로 인해 운전이 계속될수록 유량이 감소하게 된다. 이러한 단점을 극복하기 위해 이온교환수지 대신 이온전도성 스페이서를 설치하여 실험한 결과 유입유량 문제는 해결할 수 있었으나 전력소모와 금속성분 제거율 및 전류효율 면에서 비효율적인 것으로 평가되었다. 전기탈이온 공정의 연속운전에서도 금속성분 제거율에서 제염계수가 1000으로 안정적인 수준을 유지하였다.

• 한국농공학회논문집
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• 제62권5호
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• pp.39-46
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• 2020

This study evaluated the nitrogen oxide (NO_x) removal efficiency by air purification concrete blocks with titanium dioxide (TiO₂). The concrete in the mixtures had a 30% water:cement ratio, to which TiO₂ was added at 0%, 5%, and 10% of cement weight. The compressive strength reduction rate and removal efficiency of NO_x were investigated. The result of the compressive strength test in the study indicated that addition rate of TiO₂ did not lead to signifcant effect. In terms of the average removal efficiency of NO_x, mix No. 1 using a TiO₂ mixing ratio of 0% had a removal efficiency of 0.57% on average; thus, the removal effect w as not significant. For the other samples prepared by mixing, the average removal efficiencies for mix No. 2 (5% TiO₂) were 58.86% and 62.05% for normal and washing surface treatments, respectively, and those of sample No. 3 (10% TiO₂) were 59.94% and 67.61%. mixs No. 4 (5%) and No. 5 (10%), in which TiO₂ diluted with distilled water was sprayed onto the block surface, had an average NO_x removal efficiency of 61.72% and 68.48%, respectively. In terms of NOx removal efficiency, Mixs No. 3 and No. 5 with 10% TiO₂ were better than Mixs No. 2 and No. 4 with 5% TiO₂. In addition, analyzing the NO_x removal efficiency results from the fixing method, it was capable to apply mixing (washing) and the diluted spray methods. Therefore, it was found that the diluted spray method applied in this study can be employed in any manufacture of air purification concrete blocks.