• 전기학회논문지P
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• 제52권2호
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• pp.81-84
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• 2003

This paper presents a proper rational transfer function synthesis in the continuous time system from noisy measurements. The proposed method identifies the coefficients vector of the transfer function from an overdetermined linear system that develops from rearranging the two dimensional system matrices and output vectors obtained from the observed frequency responses. By computer simulation, the performance improvement is verified.

• 대한의생명과학회지
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• 제9권2호
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• pp.67-74
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• 2003

Viral and non-viral vectors have been used in the delivery of genetic materials into animal cells and tissues, with each approach having pros and cons. Non-viral vectors have many useful merits such as easy preparation, low immunity and size tolerance of a transgene when compared to those of viral vectors. Delivery specificity may be achieved by complex formation between receptor ligands and a non-viral vector. In the present study, non-viral vector systems are investigated in an effort to find a practical delivery means for gene therapy, Receptor-ligand interaction between transferrin-receptor and transferrin was utilized for efficient gene transfer into cancer cells. A plasmid vector, pcDNA3 (LacZ) was ligated with a small duplexed oligo fragment in which a Biotin- VN$^{TM}$ phosphoramidite was placed in the middle of the oligo. The plasmid vector labeled by biotin was then conjugated with biotin-labeled transferrin via streptavidin. This trimeric conjugates were delivered to a hepatoma cell line, HepG2. The delivery efficiency of the trimeric conjugate was 2-fold higher than that of cationic liposomes used for transfection of a plasmid vector. These results demonstrate that a plasmid vector can be efficiently transferred into cells by forming a trimeric complex of plasmid vector-linker-ligand.

• 한국전자파학회논문지
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• 제25권4호
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• pp.476-482
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• 2014

본 연구에서는 위성 SAR 영상을 이용한 초목층 정보 예측을 위해 옥수수의 생육에 따른 후방 산란 계수 변화를 분석한다. 이를 위하여 지상형 산란계 시스템을 이용하여 옥수수 밭의 후방 산란 계수를 측정하였으며, 지표면 정보를 입력변수로 한 1차 VRT(Vector Radiative Transfer) 기법을 이용하여 후방 산란 계수를 계산하여 측정값과 비교/분석한다. 그 결과, 생육 초기에는 옥수수보다 토양에서의 산란이 지배적이었으며, 옥수수의 밀도가 증가하면서 잎의 분포의 영향으로 입사각이 증가하면서 후방 산란 계수가 점차 상승하는 특징을 보였다. 측정 데이터와 1차 VRT 계산 오차는 평균 RMSE (Root Mean Square Error)가 VV-편파에서 1.32 dB이었고, HH-편파에서 0.99 dB이었다. 또한, 1차 VRT 계산을 통해 LAI (Leaf Area Index) 변화에 따른 작물과 토양에서의 산란 영향을 분석하였다.

• 한국가축번식학회지
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• 제19권4호
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• pp.293-305
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• 1996

Retrovirus는 DNA가 아닌 RNA를 유전 물질로 갖고 있는 동물 virus인데 각 virus는 RNA와 함께 크게 gag, pol. 그리고 env 등의 3가지 단백질로 구성되어 있다. gag 단백질은 virus의 내부구조를 형성하는 단백질이고, pol단백질은 감염을 통해 표적 세포에 도입된 retrovirus의 RNA를 DNA로 역전사시키는 reverse transcriptase의 역할을 하며, env단백질은 virusdml 외부를 구성하는 단백질로써 이 단백질에 의해 각 retrovirus의 종류에 따른 감염이 가능한 표적세포의 종류가 결정된다(host cell specificity). 따라서 어떤 retrovirus의 envelope단백질과 표식세포에 있는 retrovirus의 envelope 단백질에 대한 특정 receptor와의 상호 작용에 의해 세포속으로 도입된 virus의 RNA는 reverse transcriptase에 의해 DNA로 역전사된 후 표적세포의 genomic DNA에 삽입되는 특징을 가진다. 이러한 특징을 가진 retrovirus vector system은 형질 전환 동물의 생산에 있어서 현재까지의 주된 방법인 수정란의 pronucleus에의 DNA microinjection방법 보다 여러 가지 면에서 우수함에도 불구하고 쥐 이외의 다른 동물에서는 거의 이용되고 있지 않는 실정이다. 주된 원인으로는 현재 사용되고 있는 대부분의 retrovirus vector system이 쥐의 백혈병 virus를 근간으로 하기 때문에 이 system에서 생산된 virus는 쥐 이외의 다른 동물, 특히 유제류의 세포에는감염성이 아주 약하기 때문이다. 이러한 결점을 해결하기 위하여 최근에 기존의 쥐 백혈병 virus의 envelope protein을 vesicular stomatitis virus의 G protein으로 대체한 hybrid retrovirus vector system이 개발되었다. 이러한 system에서 생산되는 virus는 조류를 포함한 거의 모든 종류의 동물세포를 감염시킬 수 있으며 몇몇 특정세포에 대해서는 기존의 retrovirus vector system에 비해 1,000배 이상의 높은 감염도를 나타내는데 그 특징이 있다. 따라서 이러한 새로운 virus vector system을 이용할 경우, 보다 다양한 종에 있어서 형질전환 동물을 효율적으로 생산할 수 있을 뿐만 아니라 형질전환 동물의 생산 방법 자체를 다양화 시킬 수 있다고 본다.

• 한국잠사곤충학회지
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• 제39권1호
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• pp.36-43
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• 1997

In order to express the FLP recombinase in B. mori cultured cell line, BmN-4, transient expression system using a heat shock protein gene (hsp70) promoter of Dorosophilla melnogaster was constructed. This vector was designated as pHsSV. Activity strength of the hsp70 promoter was compared with that of immediate early gene (IE-1) and polyhedrin gene of BmNPV employing the E. coli $\beta$-galactosidase gene as a reporter gene. The result showed that the pHs $\beta$-gal plasmid vector expressed the $\beta$-galactosidase at 2nd and 3rd day after the transfer of plasmid DNA into BmN-4 cells, which was similar to that of pIE1 $\beta$-gal vector, but different from that of a recombinant virus, vBm $\beta$-gal. For the construction of FLP recombinase transient expression vector, the FLP recombinase gene was cloned by polymerase chain reaction technique. To express the FLP recombinase, this gene was inserted into pHsSV plasmid vector, under the control of the hsp70 promotor, and tranfected in BmN-4 cells. The expressed FLP recombinase was estimated at 44kDa on a 12.5% SDS-PAGE.

• 한국가축번식학회지
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• 제19권2호
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• pp.89-93
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• 1995

In this study was demonstrate that retrovirus-mediated gene transfer is one of the promising alternatives to the conventional pronuclear DNA microinjection approach, especially in transferring the exogenous genes into the boving embryos. By co-culturing of zona of zona-free one-cell stage embryos with the retrovirus-producing cells for 24 hours followed by 6 days of culture in virus-free medium, we could get morulae and blastocysts expressing the E. coli LacZ genes which were transferred by our retrovirus vector. The results obtained in this study are summarized as follows : 1. Addition of 5$\mu\textrm{g}$/ml of polybrene in the embryo and virus-producing cell co-culture medium did not affect development of zona-free one-cell embryo. 2. Compared with the intact embryos removal of zona at one-cell stage before co-culturing with the virus-producing cells for one day caused only slight decrease of embryo develpment. 3. Co-culture of 625 zona-free one-cell stage embryos with the virus-producing cells resulted in 65(10.4%) morulae or blastocysts, and 12.3%(8/65) of the morulae or blastocysts were E. coli LacZ positive.

• Journal of Microbiology and Biotechnology
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• 제9권3호
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• pp.318-322
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• 1999

A new baculovirus transfer vector (pPGP404) was constructed to increase the expression level of human thrombopoietin (hTPO) in insect cells. In pPGP404, hTPO was cloned next to the AcNPV polyhedrin-gp64 dual promoter and the leader sequence of hTPO was substituted with that of gp64. A recombinant baculovirus, AcPGP404, was constructed by using pPGP404 as a transfer vector. hTPO was expressed in AcPGP404-infected TN5 cells and it was observed that the expression levels of hTPO in TN5 cells increased three-fold ($6.0 {\mu}g/ml^{-1}$) compared to the level expressed under the control of the polyhedrin single promoter. These results indicate that the polyhedrin-gp64 dual promoter system would be useful for expression in large quantities of recombinant proteins in insect cells.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2005년도 춘계 학술대회논문집
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• pp.79-84
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• 2005

The numerical solutions are examined on the effect of a centered heat conducting body on natural convection in a 2-D square cavity. The influences of the Rayleigh number, the dimensionless conducting body size, and the ratio of the thermal diffusivity of the body to that of the fluid have been investigated on the natural convection heat transfer in overall concerned region. The analysis reveals that the fluid flow and heat transfer processes are governed by all of them. Results for isotherms, vector plots and wall Nusselt numbers are reported for Pr = 0.71 and relatively wide ranges of the other parameters. Heat transfer across the cavity, in comparison to that in the absence of a body, are enhanced (reduced) in general by a body with a thermal diffusivity ratio less (greater) than unity. The heat transfer are also found to attain a minimum as the body size is increased.

• 한국동물번식학회:학술대회논문집
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• 한국동물번식학회 2004년도 춘계학술발표대회
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• pp.220-220
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• 2004

The purpose of this study was to development of transgenic cow using the nuclear transfer. To secrete hFSH in urea, the vector was constructed with UPII promoter. The fetal fibroblast cells (KbFF) were constructed from pregnant day 45 male fetus. The hFSH genes were cotransfected with pcDNA3 (neo) vector to KbFF cells by electroporation. (omitted)

• 한국초지조사료학회지
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• 제20권1호
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• pp.13-18
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• 2000

An efficient method for Agrobacterium-mediated transformation of forage crop alfalfa (Medicago sativa L.) was established using secondary somatic embryogenic calli. Agrobacterium tumefaciens strain EHAlOl and a binary vector pIG121-Hm which has selection markers for kanamycin and hygromycin have been shown to be an efticient materials for alfalfa transformation. The secondary somatic embryogenic calli originated from hypocotyl explants of alfalfa were efficient infection materials for Agrobacterium EHAlOl and normally germinated into plantlets. The introduced gene (GUS) was constitutively expressed in all tissues of transgenic alfalfa with different expression levels. These results indicate that the use of pIG121-Hm vector, Agrobacterium EHAlOl and improved culture system of callus facilitate the transformation of alfalfa. (Key words : Agrobacterium, Alfalfa, Gene transfer, Transformation)