• Environmental Mutagens and Carcinogens
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• v.22 no.3
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• pp.175-182
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• 2002

Endocrine disruptors (EDs) are the chemicals that affect endocrine systems through activation or inhibition of steroid hormone response. It is necessary to have a good system to evaluate rapidly and accurately endocrine-disrupting activities of suspected chemicals and their degradation products. The key targets of EDs are nuclear hormone receptors, which bind to steroid hormones and regulate their gene transcription. We constructed a co-expression system of Gal4p DNA binding domain (DBD)- ligand binding domain of human estrogen receptor $\alpha$ or $\beta$, and Gal4p transactivation domain (TAD)-co-activator AIB-1, SRC-1 or TIF-2 in Saccharomyces cerevisiae with a chromosome-integrated lacZ reporter gene under the control of CYC1 promoter and Gal4p binding site (GAL4 upstream activating sequence, GAL4$_{UAS}$). Expression of this reporter gene was dependent on the presence of estrogen or EDs in the culture medium. We found that the two-hybrid system with combination of the hER$\beta$ LBD and co-activator SRC-1 was most effective in the xenoestrogen-dependent induction of reporter activity. The extent of transcriptional activation by those chemicals correlated with their estrogenic activities measured by other assay systems, indicating that this assay system is efficient and reliable for measuring estrogenic activity. The data in this research demonstrated that the yeast detection system using steroid hormone receptor and co-activator is a useful tool for identifying chemicals that interact with steroid receptors.s.

• Journal of the Korean Institute of Intelligent Systems
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• v.13 no.2
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• pp.175-179
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• 2003

Convergence condition determines performance of iterative learning control (ILC), for example, convergence speed, remaining error, etc. Hence, the performance can be elevated and a feasible set of learning controllers grows if a less conservative condition is obtained. In the frequency domain, the $H_{\infty}$ norm of the transfer function between consecutive errors has been currently used to test convergence of a learning system. However, even if the convergence condition based on the $H_{\infty}$ norm has a clear property about monotonic convergence, it has a few drawbacks, especially in MIMO plants. In this paper, the relation between the condition and the monotonicity of convergence is clarified and a modified convergence condition is found out using a frequency domain Lyapunov equation, which supersedes the conventional one in the frequency domain.

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.197-203
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• 2001

A fusion protein, consisting of human epidermal growth factor as a recognition domain and human angiogenin as a toxin domain, can be used as a targeted therapeutic against breast cancer cells among others. The fusion protein was expressed as inclusion body in recombinant E. coli, and when the conventional, solution-phase refolding process was used the refolding yield was very low due to severe aggregation, probably due to the opposite surface charge due to vastly different pI values of each domain. Solid-phase refolding process exploiting ionic interactions between the solid matrix and the protein was tried, but the ionic binding yield was very low regardless of the resins and pH conditions used. To provide higher affinity toward the solid matrix, six lysine residues were tagged to the N -terminus of the hEGF domain When the cation exchange resins such as heparin- or CM-Sepharose were used as the matrix, the adsorption capacity increased 2.5-3 times and the subsequent refolding yield increased nearly IS times compared to the conventional process.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.48 no.1
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• pp.23-32
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• 2011

In this paper, we develop a method for generating thumbnail images at hybrid domain combined the spatial domain and transform domain. The proposed method generates a pixel of a thumbnail image by adding a DC value of residual transform coefficients and an average value of an estimate block. For effectively calculating average values of estimate blocks, we propose a method for reconstructing the boundary pixels of a block. In comparison to the conventional method of decoding the bit stream then scaling down the decoded images, the developed method reduces the complexity by more than 60% while producing identical thumbnail images.

• Bulletin of the Korean Chemical Society
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• v.22 no.12
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• pp.1361-1365
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• 2001

Recombinant immunotoxins are hybrid cytotoxic proteins designed to selectively kill cancer cells. A divalent immunotoxins, [B3(FabH1)-PE38]2, was constructed by recombining Fab domain of B3 antibody as a cell-targeting domain and Pseudo monas exotoxin A (PE) as a cytotoxic domain. Monoclonal antibody, B3, is the murine antibody (IgG1k) directed against Lewis Y-related carbohydrate antigens, which are abundant on the surface of many carcinomas. Fab fragment of this antibody was used in this study with the modified hinge sequence where last two cysteines out of three were mutated to serine. PE is a 66 kDa bacterial toxin that kills eukaryotic cells by inhibiting protein synthesis with ADP ribosylation of ribosomal elongation factor 2 (EF2). Fc region of B3 antibody was substituted with the truncated form of PE (38 kDa, PE38) on DNA level. [B3(FabH1)-PE38]2 was formed by disulfide bond between cysteines in the modified hinge region of B3(FabH1)-PE38. Each polypeptide for recombinant immunotoxins was overexpressed in Escherichia coli and collected as inclusion bodies. Each inclusion body was solubilized and refolded, and cytotoxic effects were measured. Divalent immunotoxins, [B3(FabH1)-PE38]2, had ID50 values of about 10 ng/mL on A431 cell lines and about 4 ng/mL on CRL1739 cell lines. Control immunotoxins, B3(scFv)-PE40, had ID50 values of about 28 ng/mL on A431 cell lines and about 41 ng/mL on CRL1739 cell lines. Divalent immunotoxins, [B3(FabH1)-PE38]2, had higher cytotoxic effects than B3(scFv)-PE40 control immunotoxins.

• Journal of Broadcast Engineering
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• v.14 no.4
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• pp.501-508
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• 2009

This paper proposes an efficient transform-domain noise reduction scheme in an H.264 video encoder, where the generalized Wiener filtering is performed in a quantization process by multiplying each transform block with its adaptive multiplication factor. In practice, the computational complexity of the proposed scheme is negligible by replacing the multiplication operation with a simple look-up table method. Also, experimental results show that the proposed scheme provides outstanding noise reduction performance in an H.264 video encoder.

• Proceedings of the Korean Information Science Society Conference
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• 2001.04a
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• pp.295-297
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• 2001

현재 인터넷 망에서 실시간 트래픽과 양 방향 전송을 실현하기 위한 인터넷 전화는 비용과 서비스측면에서의 장점을 바탕으로 많은 관심을 끌고 있다. 지금까지의 인터넷 전화 프로토콜의 대표적인 표준안은 ITU에서 제안된 H.323과 IETF에서 제안된 SIP(Session Initiation Protocol)이다. 그러나, 현재의 H.323 표준안은 유선망과 고정 호스트로 이루어진 패킷망에 적합하도록 설계되었기 때문에 이동 인터넷망의 특성을 고려하지 않고 있다. 본 논문에서는 이동환경에서 인터넷 전화 서비스를 제공하기 위한 Mobile IP와 H.323dml 통합 구조를 제안하였다. 현재 Mobile IP에서 제안된 표준안을 확장함으로써 인트라 도메인(intra-domain)에서의 IP 이동성을 제공하도록 하였으며, 인터 도메인(inter-domain)에서의 IP 이동성을 제공하기 위하여 게이트웨이에서의 다중 연결 유징 방법을 제안하였다. 따라서, 본 논문에서 제안한 방법은 기존의 H.323 표준의 최소 변경과 추가적인 새로운 개체의 정의가 필요 없으며, 기존의 H.323 시스템들과 호환성을 유지할 수 있다는 장점을 지니고 있다.

• Development and Reproduction
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• v.17 no.4
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• pp.299-309
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• 2013

Transforming growth factor (TGF) family is well known to induce the chondrogenic differentiation of mesenchymal stem cells (MSC). However, the precise signal transduction pathways and underlying factors are not well known. Thus the present study aims to evaluate the possible role of C2 domain in the chondrogenic differentiation of human mesenchymal stem cells. To this end, 145 C2 domains in the adenovirus were individually transfected to hMSC, and morphological changes were examined. Among 145 C2 domains, C2 domain of protein kinase C eta ($PKC{\eta}$) was selected as a possible chondrogenic differentiation factor for hMSC. To confirm this possibility, we treated $TGF{\beta}3$, a well known chondrogenic differentiation factor of hMSC, and examined the increased-expression of glycosaminoglycan (GAG), collagen type II (COL II) as well as $PKC{\eta}$ using PT-PCR, immunocytochemistry and Western blot analysis. To further evaluation of C2 domain of $PKC{\eta}$, we examined morphological changes, expressions of GAG and COL II after transfection of $PKC{\eta}$-C2 domain in hMSC. Overexpression of $PKC{\eta}$-C2 domain induced morphological change and increased GAG and COL II expressions. The present results demonstrate that $PKC{\eta}$ involves in the TGF-${\beta}3$-induced chondrogenic differentiation of hMSC, and C2 domain of $PKC{\eta}$ has important role in this process.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.11C
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• pp.917-924
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• 2008

Motion estimation and compensation in the spatial domain check the searching area of specified size in the previous frame and search block to minimize the difference with current block. When we check the searching area, it consumes the most encoding times due to increasing the complexity. We can solve this fault by means of motion estimation using shifting matrix in the transform domain instead of the spatial domain. We derive so the existed shifting matrix to a new recursion equation that we decrease more computations. We modify simply vertical shifting matrix and horizontal shifting matrix in the transform domain for motion estimation of half-pixel accuracy. So, we solve increasing computation due to bilinear interpolation in the spatial domain. Simulation results prove that motion estimation by the proposed algorithm in DCT-based transform domain provides higher PSNR using fewer bits than results in the spatial domain.

• Journal of Electrical Engineering and information Science
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• v.3 no.2
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• pp.193-201
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• 1998

In this paper, the standard Dole, Glover, Khargoneker, and Francis (abbr. : DGKF 1989) H\ulcorner controller (H\ulcornerC) is extended to the nonlinear feedback linearization-H\ulcorner/sliding mode controller (NFL-H\ulcorner/SMC), to tackle the problem of the unmeasurable state variables as in the conventional SMC, to obtain smooth control as the linearized controller in a linear system, and to improve the time-domain performance under a worst scenario. The proposed controller is obtained by combining the H\ulcorner estimator with the nonlinear feedback linearization-sliding mode controller (NFL-SMC) and it does not need to measure all the state variables as in the traditional SMC. The proposed controller is applied as a nonlinear power system stabilizer (PSS) for the improvement of the power system damping characteristics of an single machine infinite bus system (SMIBS) connected through a double circuit line. The effectiveness of the proposed controller is verified by nonlinear time-domain simulation in case of a 3-cycle line-to-ground fault and in case of the parameter variations for the AVR gain K\ulcorner and for the inertia moment M.