The PPLA motif of glycogen synthase kinase 3beta is required for interaction with Fe65.

Lee, Eun Jeoung,Hyun, Sunghee,Chun, Jaesun,Shin, Sung Hwa,Lee, Kyung Eun,Yeon, Kwang Hum,Park, Tae Yoon,Kang, Sang Sun Korean Society for Molecular Biology 2008 Molecules and cells Vol.26 No.1

<P>Glycogen synthase kinase 3beta (GSK 3 beta) is a serine/ threonine kinase that phosphorylates substrates such as beta-catenin and is involved in a variety of biological processes, including embryonic development, metabolism, tumorigenesis, and cell death. Here, we present evidence that human GSK 3beta is associated with Fe65, which has the characteristics of an adaptor protein, possessing a WW domain, and two phosphotyrosine interaction domains, PID1 and PID2. The GSK 3beta catalytic domain also contains a putative WW domain binding motif ((371)PPLA(374)), and we observed, using a pull down approach and co-immuno-precipitation, that it interacts physically with Fe65 via this motif. In addition, we detected co-localization of GSK 3beta and Fe65 by confocal microscopy, and this co-localization was disrupted by mutation of the putative WW domain binding motif of GSK 3beta.Finally, in transient transfection assays interaction of GSK 3 beta (wt) with Fe65 induced substantial cell apoptosis, whereas interaction with the GSK 3beta AALA mutant ((371)AALA(374)) did not, and we noted that phosphorylation of the Tyr 216 residue of the GSK 3beta AALA mutant was significantly reduced compared to that of GSK 3beta wild type. Thus, our observations indicate that GSK 3beta binds to Fe65 through its (371)PPLA(374) motif and that this interaction regulates apoptosis and phosphorylation of Tyr 216 of GSK 3beta.</P>

Use of the reciprocity theorem for a closed form solution of scattering of the lowest axially symmetric torsional wave mode by a defect in a pipe

Lee, Jaesun,Achenbach, Jan D.,Cho, Younho Elsevier 2018 Ultrasonics Vol.84 No.-

<P><B>Abstract</B></P> <P>Guided waves can effectively be used for inspection of large scale structures. Surface corrosion is often found as major defect type in large scale structures such as pipelines. Guided wave interaction with surface corrosion can provide useful information for sizing and classification. In this paper, the elastodynamic reciprocity theorem is used to formulate and solve complicated scattering problems in a simple manner. The approach has already been applied to scattering of Rayleigh and Lamb waves by defects to produce closed form solutions of amplitude of scattered waves. In this paper, the scattering of the lowest axially symmetric torsional mode, which is widely used in commercial applications, is analyzed by the reciprocity theorem. In the present paper, the theorem is used to determine the scattering of the lowest torsional mode by a tapered defect that was earlier considered experimentally and numerically by the finite element method. It is shown that by the presented method it is simple to obtain the ratio of amplitudes of scattered torsional modes for a tapered notch. The results show a good agreement with earlier numerical results. The wave field superposition technique in conjunction with the reciprocity theorem simplifies the solution of the scattering problem to yield a closed form solution which can play a significant role in quantitative signal interpretation.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The scattering of the lowest torsional mode is analyzed by the reciprocity theorem. </LI> <LI> The solution of wave scattering amplitude ratio is presented in simple form. </LI> <LI> The presented method is simple to obtain the scattered amplitude compared to FEM. </LI> <LI> This results can play a significant role in quantitative signal interpretation. </LI> </UL> </P>

Genetic EBPylation as an Alternative to chemical PEGylation

JAESUN LEE,SUJIN JUNG,EUNKYU LEE 한국생물공학회 2016 한국생물공학회 학술대회 Vol.2016 No.4

Study on Anti-adipogenic and Antioxidant Potency of Erigeron annuus (L.) Pers. (EAP) Extract In vitro System

Jaesun Lee,Yoon-Hee Choi,Yulong Zheng,Eun-Hye Lee,Il-Jun Kang 한국식품영양과학회 2018 한국식품영양과학회 학술대회발표집 Vol.2018 No.10

In Situ Growth of Nanostructured BiVO₄-Bi₂O₃ Mixed-Phase via Nonequilibrium Deposition Involving Metal Exsolution for Enhanced Photoelectrochemical Water Splitting

Lee, Seungchul,Song, Jaesun,Jo, Yong-Ryun,Choi, Kyoung Soon,Lee, Jongmin,Seo, Sehun,Kim, Taemin Ludvic,Jang, Ho Won,Jeon, Cheolho,Kim, Bong-Joong,Kim, Bongjae,Lee, Sanghan American Chemical Society 2019 ACS APPLIED MATERIALS & INTERFACES Vol.11 No.47

<P>Nonequilibrium deposition is a remarkable method for the in situ growth of unique nanostructures and phases for the functionalization of thin films. We introduce a distinctive structure of a mixed-phase, composed of BiVO<SUB>4</SUB> and β-Bi<SUB>2</SUB>O<SUB>3</SUB>, for photoelectrochemical water splitting. The mixed-phase is fabricated via nonequilibrium deposition by adjusted oxygen partial pressure. According to density functional theory calculations, we find that vanadium exsolution can be facilitated by introducing oxygen vacancies, enabling the fabrication of a nanostructured mixed-phase. These unique structures enhance charge migration by increasing the interfacial area and properly aligning the band offset between two crystalline phases. Consequently, the photocurrent density of the nanostructured mixed-phase thin films is about twice that of pristine BiVO<SUB>4</SUB> thin films at 1.23 V<SUB>RHE</SUB>. Our work suggests that nonequilibrium deposition provides an innovative route for the structural engineering of photoelectrodes for the understanding of fundamental properties and improving the photocatalytic performance for solar water splitting.</P> [FIG OMISSION]</BR>

Using Lamb Waves to Monitor Moisture Absorption in Thermally Fatigued Composite Laminates

Jaesun Lee,Younho Cho 한국비파괴검사학회 2016 한국비파괴검사학회지 Vol.36 No.3

Nondestructive evaluation for material health monitoring is important in aerospace industries. Composite laminates are exposed to heat cyclic loading and humid environment depending on flight conditions. Cyclic heat loading and moisture absorption may lead to material degradation such as matrix breaking, debonding, and delamination. In this paper, the moisture absorption ratio was investigated by measuring the Lamb wave velocity. The composite laminates were manufactured and subjected to different thermal aging cycles and moisture absorption. For various conditions of these cycles, not only changes in weight and also ultrasonic wave velocity were measured, and the Lamb wave velocity at various levels of moisture on a carbon-epoxy plate was investigated. Results from the experiment show a linear correlation between moisture absorption ratio and Lamb wave velocity at different thermal fatigue stages. The presented method can be applied as an alternative solution in the online monitoring of composite laminate moisture levels in commercial flights.

Using Lamb Waves to Monitor Moisture Absorption in Thermally Fatigued Composite Laminates

Lee, Jaesun,Cho, Younho The Korean Society for Nondestructive Testing 2016 한국비파괴검사학회지 Vol.36 No.3

Nondestructive evaluation for material health monitoring is important in aerospace industries. Composite laminates are exposed to heat cyclic loading and humid environment depending on flight conditions. Cyclic heat loading and moisture absorption may lead to material degradation such as matrix breaking, debonding, and delamination. In this paper, the moisture absorption ratio was investigated by measuring the Lamb wave velocity. The composite laminates were manufactured and subjected to different thermal aging cycles and moisture absorption. For various conditions of these cycles, not only changes in weight and also ultrasonic wave velocity were measured, and the Lamb wave velocity at various levels of moisture on a carbon-epoxy plate was investigated. Results from the experiment show a linear correlation between moisture absorption ratio and Lamb wave velocity at different thermal fatigue stages. The presented method can be applied as an alternative solution in the online monitoring of composite laminate moisture levels in commercial flights.

유도 초음파를 이용한 락 플레이트 물성 평가

이재선(Jaesun Lee),조윤호(Younho Cho),정경식(Kyoungsik Jeong) 대한기계학회 2009 大韓機械學會論文集A Vol.33 No.4

Presented in this paper is a new experimental technique to measure material properties of lock plate of gas turbine plants by using ultrasonic guided wave. In comparison with the mechanical destructive testings, material characterization of the Inconel x-750 was nondestructively carried out in a more efficient manner to discriminate the change in elastic moduli and the poisson's ratio attributed to the variation of heat treatment condition. The proposed technique shows a satisfactory feasibility via the comparative experiments with the imported lock plate specimens. It is also expected that the guided wave technique can cover a longer and wider range as a new cost-&-time-saving inspection tool due to the interaction with a greater part of specimen, compared to a conventional local point-by-point scheme.

위상배열 유도초음파 검사의 이론적 고찰

이재선(Jaesun Lee),조윤호(Younho Cho),Jan D. Achenbach 한국비파괴검사학회 2011 한국비파괴검사학회지 Vol.31 No.4

유도초음파를 활용한 진단 기술은 기존의 체적파를 이용한 진단 기법과 달리 장거리 진단의 장점 때문에 널리 사용된다. 대부분의 산업현장에서는 배관이 코팅되어 있거나 땅속이 묻혀있다. 이러한 경우 감쇠의 영향으로 기존의 방식으로는 진단에 어려움이 있다. 본 연구에서는 배관에서 전파되는 유도초음파 전파 모드별 음장을 직교모드확장기법을 이용하여 계산하였다. 단일 탐촉자에 의해 전파되는 유도초음파의 음장과 다중 탐촉자 모델링을 바탕으로 배관에서 전파되는 음장 특성을 해석하기 위해 유도초음파 모드별 집속 기술이 사용되었다. 추가적으로 배관에서 전파되는 유도초음파를 가진하는 탐촉자의 개수에 따른 집속 민감도가 종형 모드와 휨형 모드를 이용하여 계산되었다. 본 연구를 통하여 단일 탐촉자에 의해 가진된 유도초음파와 집속 알고리즘을 적용한 다중 탐촉자에 의해 가진된 음장을 비교하여 높은 에너지가 집속 되는 것을 확인 하였다. Guided waves inspection techniques that are different with inspection technique by bulk waves are widely used in pipe line evaluation due to advantages of long distance inspection. However, most of pipe lines at industrial fields are buried and/or coated. In this case, due to the attenuation effect from soil and/or coating material, there are a lot of difficulty on inspection by conventional ultrasonic technique. In this paper, guided waves propagating patterns are calculated with respect to excitation mode by Normal Mode Expansion(NME). Guided waves patterns based on excited by single transducer and guided wave focusing technique have employed to analyze focusing pattern on a pipe. A longitudinal mode and high order flexural modes are used with various number of transducers to determine sensitivity. Guided waves energy excited by multi transducer with focusing algorithm was successfully focused at a desired point.

Enhancement of Ferroelectric Properties of Superlattice-Based Epitaxial BiFeO₃ Thin Films via Substitutional Doping Effect

Song, Jaesun,Choi, Kyoung Soon,Yoon, Sejun,Sohn, Woonbae,Hong, Seung Pyo,Lee, Tae Hyung,An, Hyunji,Cho, Sam Yeon,Kim, So-Young,Kim, Do Hyun,Kim, Taemin Ludvic,Jeong, Sang Yun,Bark, Chung Wung,Lee, Byo American Chemical Society 2019 The Journal of Physical Chemistry Part C Vol. No.

<P>Although there is considerable interest in BiFeO<SUB>3</SUB> owing to its versatile physical properties, which make it suitable for a wide range of applications, its high leakage current is a significant limitation. Among various methods for reducing the leakage current, substitution with transition-metal or rare-earth elements is widely recognized as the most effective approach. Herein, to enable in-depth studies of the physical properties of BiFeO<SUB>3</SUB>, high-quality epitaxial BiFeO<SUB>3</SUB> thin films with a low leakage current must be formed. However, owing to the difficulty of controlling the element doping when pulsed laser deposition is used for epitaxial thin-film growth, studies on substitutional doping based on epitaxial BiFeO<SUB>3</SUB> thin films have not been systematically carried out. In this regard, we establish an innovative approach for overcoming the high leakage current of BiFeO<SUB>3</SUB> by fabricating artificially engineered superlattice-based epitaxial BiFeO<SUB>3</SUB> thin films in which there is a significant reduction of the leakage current. The control of the element doping in epitaxial BiFeO<SUB>3</SUB> thin films is easily regulated precisely at the atomic-scale level. The results of this study strongly suggest that superlattice-based epitaxial BiFeO<SUB>3</SUB> thin films can be a cornerstone for exploring the reliable fundamental physical properties of substitutional doping in epitaxial BiFeO<SUB>3</SUB> thin films.</P> [FIG OMISSION]</BR>