• 대한수학회지
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• 제51권1호
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• pp.17-53
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• 2014

Let ${\gamma}$ be a hyperbolic closed orbit of a $C^1$ vector field X on a compact boundaryless Riemannian manifold M, and let $C_X({\gamma})$ be the chain component of X which contains ${\gamma}$. We say that $C_X({\gamma})$ is $C^1$ robustly shadowable if there is a $C^1$ neighborhood $\mathcal{U}$ of X such that for any $Y{\in}\mathcal{U}$, $C_Y({\gamma}_Y)$ is shadowable for $Y_t$, where ${\gamma}_Y$ denotes the continuation of ${\gamma}$ with respect to Y. In this paper, we prove that any $C^1$ robustly shadowable chain component $C_X({\gamma})$ does not contain a hyperbolic singularity, and it is hyperbolic if $C_X({\gamma})$ has no non-hyperbolic singularity.

• 한국음향학회지
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• 제34권3호
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• pp.240-246
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• 2015

본 논문은 시간 연속성을 갖는 비음수 행렬 분해(Nonnegative Matrix Factorization, NMF)를 이용하여 잡음에 열화된 음성 신호의 음질을 개선하는 문제를 다룬다. 음성과 잡음 신호는 포아송 분포로 모델되며, NMF의 기본 벡터와 이득 벡터는 감마 분포로 모델된다. 이득 벡터의 시간 연속성은 음질 개선에 중요한 영향을 미치는 것으로 알려져 있다. 본 논문에서 시간의 연속성은 이득 벡터를 감마-마르코프 연쇄(Gamma-Markov chain, GMC) 사전 분포로 모델함으로써 이루어진다. 실험 결과는 제안된 알고리즘이 잡음 신호의 시간 연속성을 효과적으로 모델하는 것을 보여준다.

• IMMUNE NETWORK
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• 제22권1호
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• pp.5.1-5.22
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• 2022

The approval of immunotherapies such as checkpoint inhibitors (CPIs), adoptive cell therapies and cancer vaccines has revolutionized the way cancer treatment is approached. While immunotherapies have improved clinical outcome in a variety of tumor types, some cancers have proven harder to combat using single agents, underscoring the need for multi-targeted immunotherapy approaches. Efficacy of CPIs and cancer vaccines requires patients to have a competent immune system with adequate cell numbers while the efficacy of adoptive cellular therapy is limited by the expansion and persistence of cells after infusion. A promising strategy to overcome these challenges is combination treatment with common gamma-chain cytokines. Gamma-chain cytokines play a critical role in the survival, proliferation, differentiation and function of multiple immune cell types, including CD8 T-cells and NK cells, which are at the center of the anti-tumor response. While the short halflife of recombinant cytokines initially limited their application in the clinic, advancements in protein engineering have led to the development of several next-generation drug candidates with dramatically increased half-life and bioactivity. When combining these cytokines with other immunotherapies, strong evidence of synergy has been observed in preclinical and clinical cancer settings. This promising data has led to the initiation of 70 ongoing clinical trials including IL-2, IL-7, IL-15 and IL-21. This review summarizes the recent advancements of common gamma-chain cytokines and their potential as a cancer immunotherapy.

• Management Science and Financial Engineering
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• 제19권2호
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• pp.37-42
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• 2013

This paper suggests a numerical method for valuation of European and American options under the two L$\acute{e}$vy Processes, Normal Inverse Gaussian Model and the Variance Gamma model. The method is based on approximation of underlying asset price using a finite-state, time-homogeneous Markov chain. We examine the effectiveness of the proposed method with simulation results, which are compared with those from the existing numerical method, the lattice-based method.

• Fibers and Polymers
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• 제5권3호
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• pp.225-229
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• 2004

The effect of UV and $^60{Co}$ gamma radiations on the physical and mechanical properties of nylon 6 mono-filaments with different draw ratios has been studied. Specimens were exposed to either up to 25 Mrad of gamma or up to 168 hrs of intense UV irradiation. The results show that nylon mono-filaments exposed to gamma rays, with much higher quantum energy than UV, undergo a larger extent of molecular chain scission. Higher irradiation dose also results in the production of insoluble, macroscopic three-dimensional cross-linked network structure. The amorphous regions with a lower density of cohesive energy (lower molecular orientation) show a higher extent of cross linking reaction whereas amorphous regions with a higher density of cohesive energy (higher orientation) show higher extent of chain scission reaction, irrespective of UV ray or gamma ray irradiation.

• Food Science and Biotechnology
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• 제18권3호
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• pp.788-792
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• 2009

Gamma $({\gamma})-irradiation$ can be used to control pathogens such as Vibrio vulnificus in seafood. The effects of irradiation on microbial cell populations (%) have been studied in order to develop detection methods for irradiated foods. The method used in this study was ethidium bromide monoazide (EMA) real-time polymerase chain reaction (PCR), using V. vulnificus specific primer, EMA, and $SYBR^{(R)}$ Green to discriminate between ${\gamma}-irradiated$ and non-irradiated cells. Confocal microscope examination showed that ${\gamma}-irradiation$ damaged portions of the cell membrane, allowing EMA to penetrate cells of irradidated V. vulnificus. ${\gamma}-Irradiation$ at 1.08 KGy resulted in log reduction ($-1.15{\pm}0.13$ log reduction) in genomic targets derived from EMA real-time PCR. The combination cold/heat shock resulted in the highest ($-1.74{\pm}0.1$ log reduction) discrimination of dead irradiated V. vulnificus by EMA real-time PCR.

• Current Applied Physics
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• 제18권11호
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• pp.1313-1319
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• 2018

The coil-to-globule behavior of poly{${\gamma}$-2-[2-(2methoxyethoxy)ethoxy]ethoxy-3-caprolactone} (PMEEECL) as a ${\gamma}$-substituted poly (${\varepsilon}$-caprolactone) was investigated via atomistic molecular dynamics (MD) simulation. For this purpose, radius of gyration, end-to-end distance and radial distribution function of the chain in the presence of water were calculated. Consequently, the lower critical solution temperature (LCST) of PMEEECL chain at which the coil-to-globule transition takes place, was determined in each calculated parameter curve. The simulation results indicated that the LCST of PMEEECL was occurred at close to 320 K, which is in a good agreement with previous experimental results. Additionally, the appearance of sudden change in both Flory-Huggins interaction parameter (${\chi}$) and interaction energy between the PMEEECL chain and water molecules at about 320 K confirmed the calculated LCST result. The radial distribution function (RDF) results showed that the affinity of the PMEEECL side chain to water molecules is lower than its backbone.

• KSBB Journal
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• 제21권3호
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• pp.204-211
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• 2006

IFN-${\gamma}$의 대량생산을 위한 기초연구로서 IFN-${\gamma}$의 아미노 말단에 glucagon과 ferritin을 융합파트너로 각각 결합시켜 재조합 IFN-${\gamma}$의 발현을 유도하였다. 대장균 내에서 발현되는 IFN-${\gamma}$는 그 자체로 매우 강한 소수성 결합의 양상을 나타내어 inclusion body 형태로 발현된다고 알려져 있으나 OrigamiTM(DE3) 균주로부터 50% 이상의 수용성 형태로 발현시켰다. IFN-${\gamma}$로부터 융합파트너를 제거할 수 있는 system을 개발하기 위해 융합파트너와 IFN-${\gamma}$ 사이에 enterokinase cleavage site를 도입하였으며, enterokinase에 의해 IFN-${\gamma}$에는 영향을 미치지 않고 효과적으로 융합파트너를 제거할 수 있었다. 재조합 IFN-${\gamma}$의 분리 및 정제를 위해 발현벡터상의 융합파트너와 IFN-${\gamma}$사이에 6X His-tag을 도입하였고 융합파트너의 N-말단에도 6X His-tag을 추가적으로 도입함으로써 융합파트너와 더불어 enterokinase에 의해 분해되지 않은 융합단백질을 Ni-NTA agarose column으로 제거함으로서 IFN-${\gamma}$를 완전 정제할 수 있었다. IFN-${\gamma}$의 발현을 유도하는 발현유도체로서 15 mM lactose를 이용하여 5 L 발효조에서 IFN-${\gamma}$의 발현을 검토한 결과, 재조합 균체의 단위 건조질량(dry cell weight, g)으로 약 11 g DCW/L 수준의 재조합 융합단백질을 얻을 수 있었다.

• Communications for Statistical Applications and Methods
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• 제6권1호
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• pp.267-274
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• 1999

We consider a doubly stochastically perturbed dynamical system {$X_n$} generated by $X_n\Gamma_n(X_{n-1})+W_n where \Gamma_n$ is a Markov chain of random functions and $W_n$ is i.i.d. random elements. Sufficient conditions for stationarity and geometric ergodicity of $X_n$ are obtained by considering asymptotic behaviours of the associated Markov chain. Ergodic theorem and functional central limit theorem are proved.

• 식물조직배양학회지
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• 제21권6호
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• pp.353-356
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• 1994

사람 B형 간염 바이러스의 pre-S2 표면항원에 결합하는 키메라 항체 유전자(카파 및 감마사슬의 cDNA클론)를 식물체에서 발현시키기 위해 식물체 발현벡터인 pBKS-1에 XbaI 자리를 이용하여 클로닝하였다. 이들 유전자를 포함하는 대장균의 플라스미드 핵산을 추출하여 아그로박테리움에 형질전환 시켰다. 다음 담배의 조직절편과 아그로박테리움을 공동배양함으로써 담배의 형질 전환을 시도하였다. 카나마이신이 포함된 신초유기배지에서 나온 신초를 시료로 하여 Western blot을 실시함으로써 이들 유전자가 형질전환 담배에서 안정하게 발현됨을 확인하였다.