Potential roles of D-serine and serine racemase in experimental temporal lobe epilepsy

Ryu, H.J.,Kim, J.-E.,Yeo, S.-I.,Kim, D.-S.,Kwon, O.-S.,Choi, S.Y.,Kang, T.-C. Wiley Subscription Services, Inc., A Wiley Company 2010 Journal of neuroscience research Vol.88 No.11

<P>To confirm the roles of D-serinergic gliotransmission in epilepsy, we investigated the relationship between spatiotemporally specific glial responses and the D-serine/serine racemase system in mesial temporal structures following status epilepticus (SE). In control animals, D-serine and serine racemase immunoreactivities were detected mainly in astrocytes. After SE, D-serine and serine racemase immunoreactivities were increased in astrocytes. Double-immunofluorescence study revealed that up-regulation of serine racemase immunoreactivity was relevant not to D-serine immunoreactivity but to nestin or vimentin immunoreactivity. Neither D-serine nor serine racemase was found in naïve or reactive microglia. In addition, phosphorylated N-methyl-D-aspartate (NMDA) receptor subunit 1 (pNR1-Ser896) immunoreactivity in the hippocampus was increased compared with controls. Increased D-serine immunoreactivity showed direct correlation with the phosphorylation of Ser896 of NR1. Given the findings of our previous study, these findings suggest that D-serine and serine racemase in astrocytes may play roles in neuronal hyperexcitability via a cooperative activation of NMDA receptors. Furthermore, serine racemase may be involved in migration and differentiation of immature astrocytes, which is relevant to reactive astrogliosis. © 2010 Wiley-Liss, Inc.</P>

Two NF-κB inhibitor-alpha (IκBα) genes from rock bream (Oplegnathus fasciatus): Molecular characterization, genomic organization and mRNA expression analysis after immune stimulation

Lee, Y.,Umasuthan, N.,Whang, I.,Revathy, K.S.,Lee, S.,De Zoysa, M.,Oh, C.,Kang, D.H.,Noh, J.K.,Lee, J. Academic Press 2014 FISH AND SHELLFISH IMMUNOLOGY Vol.41 No.2

IκBα is a member of IκB family, which sequesters NF-κB in an inactivate form in the cytoplasm and blocks the translocation of NF-κB to nucleus. The IκBα paralogs of rock bream (OfIκBα-A and OfIκBα-B) encoded IκBα proteins with typical features including, highly conserved IκB degradation motif, six ankyrin repeats and a PEST sequence. However, their amino acid identity and similarity were only 55.6 and 69.7%, respectively suggesting that these two genes could be the two different isoforms of IκBα. The number and size of the exons of OfIκBα-A and OfIκBα-B were conserved well with all the compared vertebrate species, although they have significantly different genomic sizes. Phylogenetic analysis revealed that OfIκBα-A and OfIκBα-B proteins cluster with IκBα family members; however, they were grouped with different subclades in IκBα family. Tissue specific expression of OfIκBα mRNA was constitutively detected in all the tested tissues, and they showed the higher transcription level in heart, liver, gill and peripheral blood cells, respectively. The injection of flagellin stimulated the mRNA expression of OfIκBα paralogs in head kidney and intestine. Moreover, the OfIκBα mRNA expression in gill and liver was significantly up-regulated by LPS, poly I:C and Edwardsiella tarda challenges. The transcription of OfIκBα was up-regulated in early-phase of injection and then rapidly restored. These results suggest that the OfIκBα paralogs might be involved in rapid immune responsive reactions in rock bream against bacterial and viral pathogens.

Electric Double Layer at the Interface of Ionic Liquid–Dielectric Liquid under Electric Field

Lee, D. W.,Im, D. J.,Kang, I. S. American Chemical Society 2013 Langmuir Vol.29 No.6

<P>The structure of the electric double layer (EDL) is analyzed in order to understand the electromechanical behavior of the interface of ionic liquid-dielectric liquid. The modified Poisson–Boltzmann equation proposed by Bazant et al. is solved to see the crowding and the overscreening effects that are the characteristics of an ionic liquid (Bazant, M. Z.; Storey, B. D.; Kornyshev, A. A. Double layer in ionic liquids: Overscreening versus crowding. <I>Phys. Rev. Lett.</I><B>2011</B>, <I>106</I>, 046102.). From the simple one-dimensional (1-D) analysis, it is found that the changes of the composition and the material properties in the EDL are negligible except under some extreme conditions such as strong electric field over<I>O</I>(10<SUP>8</SUP>) V/m. From the electromechanical view points, an ionic liquid behaves like a pure conductor at the interface with a dielectric liquid. Based on these findings, three specific application problems are considered. In the first, a new method is suggested for measuring the interfacial tension of an ionic liquid-dielectric liquid system. The deformation of a charged ionic liquid droplet translating between two electrodes is used for this measurement. The second is for the Taylor cone problem, which includes an extreme electric field condition near the tip. The size of the critical region, where the EDL effect should be considered, is estimated by using the 1-D analysis result. Numerical computation is also performed to see the profiles of electric potential and the electric stress along the interface of the Taylor cone. Lastly, the electrowetting problem of the ionic liquid is considered. The discrepancies in the results of previous workers are interpreted by using the results of the present work. It is shown that all the results might be consistent if the leaking of the dielectric layer and/or the adsorption of ions is considered.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/langd5/2013/langd5.2013.29.issue-6/la3040775/production/images/medium/la-2012-040775_0013.gif'></P>

Exendin-4 induction of cyclin D1 expression in INS-1 beta-cells: involvement of cAMP-responsive element.

Kim, M-J,Kang, J-H,Park, Y G,Ryu, G R,Ko, S H,Jeong, I-K,Koh, K-H,Rhie, D-J,Yoon, S H,Hahn, S J,Kim, M-S,Jo, Y-H Journal of Endocrinology, Ltd. [etc.] 2006 The Journal of endocrinology Vol.188 No.3

<P>Glucagon-like peptide-1 (GLP-1) and its analog exendin-4 (EX) have been considered as a growth factor implicated in pancreatic islet mass increase and beta-cell proliferation. This study aimed to investigate the effect of EX on cyclin D1 expression, a key regulator of the cell cycle, in the pancreatic beta-cell line INS-1. We demonstrated that EX significantly increased cyclin D1 mRNA and subsequently its protein levels. Although EX induced phosphorylation of Raf-1 and extracellular-signal-regulated kinase (ERK), both PD98059 and exogenous ERK1 had no effect on the cyclin D1 induction by EX. Instead, the cAMP-elevating agent forskolin induced cyclin D1 expression remarkably and this response was inhibited by pretreatment with H-89, a protein kinase A (PKA) inhibitor. Promoter analyses revealed that the cAMP-responsive element (CRE) site (at position -48; 5'-TAACGTCA-3') of cyclin D1 gene was required for both basal and EX-induced activation of the cyclin D1 promoter, which was confirmed by site-directed mutagenesis study. For EX to activate the cyclin D1 promoter effectively, CRE-binding protein (CREB) should be phosphorylated and bound to the putative CRE site, according to the results of electrophoretic mobility shift and chromatin immunoprecipitation assays. Lastly, a transfection assay employing constitutively active or dominant-negative CREB expression plasmids clearly demonstrated that CREB was largely involved in both basal and EX-induced cyclin D1 promoter activities. Taken together, EX-induced cyclin D1 expression is largely dependent on the cAMP/PKA signaling pathway, and EX increases the level of phosphorylated CREB and more potently trans-activates cyclin D1 gene through binding of the CREB to the putative CRE site, implicating a potential mechanism underlying beta-cell proliferation by EX.</P>

청소년의 근로 여부에 따른 신체활동 및 스트레스 비교

강지은,김혜원,백다인,신지원,신혜진,심지선,윤도연,이규리,이보라,이혜민,최주연 이화여자대학교 간호과학대학 2014 이화간호학회지 Vol.- No.48

Purpose: The purpose of this study was to investigate the stress and the physical activity according to working in Korean adolescents. Methods: Data were collected from 3 high schools in Seoul and Gyeonggi-do. The total number of four hundred twenty subjects were participated and they completed general questionnaire, International Physical Activity Questionnaire (Korean version) and adolescents stress scale. Data were analyzed by descriptive statistics and t-test using SPSS 21.0 program. Results: The number of employed was 151 (45.2%) and the number of unemployed was 183 (54.8%). Reasons for working were to earn money (44.0%) and to purchase significant product (35.6%). Moderate physical activities of employed students were more than them of unemployed students and there was significant difference (t=3.261, p˂.001). There was no significant difference between employed and unemployed students in the total score of stress. However, there were significant differences on school stress (t=2.854, p=.005) and economical stress (t=3.959, p˂.001) in the subcategory. The stress of employed was higher than the stress of unemployed. Conclusion: As shown in the above result, employed adolescents reported higher levels of both physical activity and stress than unemployed adolescents, thus indicating that employment status of adolescents has a significant impact on physical and mental health. Nursing implications include developing quality care for employed adolescents based on the community health nursing, and providing health education at schools in terms of adolescent employment.

Effects of dihydrotestosterone on rat dermal papilla cells in vitro

Kang, J.I.,Kim, S.C.,Kim, M.K.,Boo, H.J.,Kim, E.J.,Im, G.J.,Kim, Y.H.,Hyun, J.W.,Kang, J.H.,Koh, Y.S.,Park, D.B.,Yoo, E.S.,Kang, H.K. North-Holland ; Elsevier Science Ltd 2015 european journal of pharmacology Vol.757 No.-

Androgenetic alopecia involves the action of dihydrotestosterone (DHT) on dermal papilla cells (DPCs) that line the base of the hair follicle. However, the mechanism of DHT action is not completely understood. The effects of DHT on DPCs, regulatory cells that function in follicle growth and the hair cycle, were examined in immortalized cells derived from rat vibrissa follicles. DHT did not affect the proliferation of immortalized DPCs. However, flow cytometry analysis revealed that DHT increased cell-cycle arrest in these cells, which was accompanied by an increase in the p27<SUP>kip1</SUP> level and by decreases in cyclin E, cyclin D1, and cyclin-dependent kinase 2 levels. DHT treatment resulted in the phosphorylation and nuclear translocation of Smad2/3, a mediator of the transforming growth factor-β (TGF-β) signaling pathway, which leads to the catagen phase of the hair cycle. DHT also induced the phosphorylation and nuclear translocation of heat shock protein 27 (HSP27). Moreover, DHT decreased the levels of total and nuclear β-catenin, an important regulator of hair growth and proliferation, while lithium chloride, a glycogen synthase kinase-3β inhibitor, attenuated the DHT-induced downregulation of the β-catenin level. On the other hand, DHT increased the phosphorylation of mammalian target of rapamycin (mTOR), a regulator of proliferation, in immortalized DPCs. These results illustrate that DHT could shorten the duration of the hair growth cycle by initiating cell-cycle arrest, downregulating the β-catenin level, and upregulating the TGF-β/Smad and HSP27 level, whereas activation of mTOR by DHT could attenuate the inhibition of hair growth cycle in immortalized DPCs.

Thermal effects on nonlinear vibration of a carbon nanotube-based mass sensor using finite element analysis

Kang, D.K.,Kim, C.W.,Yang, H.I. North-Holland 2017 Physica E, Low-dimensional systems & nanostructure Vol.85 No.-

In the present study we carried out a dynamic analysis of a CNT-based mass sensor by using a finite element method (FEM)-based nonlinear analysis model of the CNT resonator to elucidate the combined effects of thermal effects and nonlinear oscillation behavior upon the overall mass detection sensitivity. Mass sensors using carbon nanotube (CNT) resonators provide very high sensing performance. Because CNT-based resonators can have high aspect ratios, they can easily exhibit nonlinear oscillation behavior due to large displacements. Also, CNT-based devices may experience high temperatures during their manufacture and operation. These geometrical nonlinearities and temperature changes affect the sensing performance of CNT-based mass sensors. However, it is very hard to find previous literature addressing the detection sensitivity of CNT-based mass sensors including considerations of both these nonlinear behaviors and thermal effects. We modeled the nonlinear equation of motion by using the von Karman nonlinear strain-displacement relation, taking into account the additional axial force associated with the thermal effect. The FEM was employed to solve the nonlinear equation of motion because it can effortlessly handle the more complex geometries and boundary conditions. A doubly clamped CNT resonator actuated by distributed electrostatic force was the configuration subjected to the numerical experiments. Thermal effects upon the fundamental resonance behavior and the shift of resonance frequency due to attached mass, i.e., the mass detection sensitivity, were examined in environments of both high and low (or room) temperature. The fundamental resonance frequency increased with decreasing temperature in the high temperature environment, and increased with increasing temperature in the low temperature environment. The magnitude of the shift in resonance frequency caused by an attached mass represents the sensing performance of a mass sensor, i.e., its mass detection sensitivity, and it can be seen that this shift is affected by the temperature change and the amount of electrostatic force. The thermal effects on the mass detection sensitivity are intensified in the linear oscillation regime and increase with increasing CNT length; this intensification can either improve or worsen the detection sensitivity.

Organic-inorganic hybrid photocatalyst for carbon dioxide reduction

Won, D. I.,Lee, J. S.,Cheong, H. Y.,Cho, M.,Jung, W. J.,Son, H. J.,Pac, C.,Kang, S. Royal Society of Chemistry 2017 Faraday discussions Vol.198 No.-

<P>Efficient hybrid photocatalysts for carbon dioxide reduction were developed from dye-sensitized TiO2 nanoparticles and their catalytic performance was optimized by ternary organic/inorganic components. Thus, the hybrid system consists of (E)-2-cyano-3-(5'(5 ''-(p-(diphenylamino)phenyl)thiophen-2 ''-yl)thiophen-2'-yl)-acrylic acid as a sensitizer and fac-[Re(4,4'-bis(diethoxyphosphorylmethyl)-2,2'-bipyridine)(CO)(3)Cl] as a reduction catalyst (ReP), both of which have been fixed onto TiO2 semiconductors (s-TiO2, h-TiO2, d-TiO2). Mott-Schottky analysis on flat-band potential (E-fb) of TiO2 mesoporous films has verified that Efb can be finely modulated by volume variation of water (0 to 20 vol%). The increase of added water resulted in substantial positive shifts of Efb from -1.93 V at 0 vol% H2O, to -1.74 V (3 vol% H2O), to -1.56 V (10 vol% H2O), and to -1.47 V (20 vol% H2O). As a result, with addition of 3-10 vol% water in the photocatalytic reaction, conversion efficiency of CO2 to CO increased significantly reaching a TON value of similar to 350 for 30 h. Catalytic activity enhancement is mainly attributed to (1) the optimum alignment of Efb by 3-10 vol% water with respect to the E-ox* of the dye and E-red of ReP for smooth electron transfer from photo-excited dye to ReP via the TiO2 semiconductor and (2) the water-induced acceleration of chemical processes on the fixed ReP. In addition, the energy level was further tuned by variation of the dye and ReP amounts. We also found that the intrinsic properties of TiO2 sources (morphology, size, agglomeration) exert a great influence on the overall photocatalytic activity of this hybrid system. Implications of the present observations and reaction mechanisms are discussed in detail.</P>

Analysis of Self-Heating Effects on vertical FET according to Shallow Trench Isolation

Myeong, I.,Son, D.,Kim, H.,Kang, M.,Shin, H. Pergamon Press ; Elsevier Science Ltd 2017 Solid-state electronics Vol.137 No.-

In this paper, Self-Heating Effect (SHE) according to depth of STI was analyzed and STI thickness optimization was performed in the plate-shaped vertical field effect transistor (VFET). In case of a VFET, the path of leakage current (I<SUB>off</SUB>) is different from that of a lateral FET (LFET). Asa result, I<SUB>off</SUB> of VFET is not influenced by STI depth. For this reason, the STI depth of the VFET is not needed as much as the depth needed to reduce I<SUB>off</SUB> in the LFET. Asa result, if the STI depth of the VFET is reduced from 100nm to 20nm, which is the drain region depth doped with Arsenic, thermal resistance (R<SUB>th</SUB>) is expected to be reduced by 32.19% and on current (I<SUB>on</SUB>) is expected to be increased by 1.54% without affecting the I<SUB>off</SUB> as compared with STI depth of 100nm in VFET.

Subnormal and quasinormal Toeplitz operators with matrix-valued rational symbols

Curto, R.E.,Hwang, I.S.,Kang, D.O.,Lee, W.Y. Academic Press ; Elsevier Science B.V. Amsterdam 2014 Advances in mathematics Vol.255 No.-

In this paper we deal with the subnormality and the quasinormality of Toeplitz operators with matrix-valued rational symbols. In particular, in view of Halmos's Problem 5, we focus on the question: Which subnormal Toeplitz operators are normal or analytic? We first prove: Let Φ@?L<SUB>M'n</SUB><SUP>~</SUP> be a matrix-valued rational function having a ''matrix pole'', i.e., there exists α@?D for which kerH<SUB>Φ</SUB>@?(z-α)H<SUB>C^n</SUB><SUP>2</SUP>, where H<SUB>Φ</SUB> denotes the Hankel operator with symbol Φ. If(i)T<SUB>Φ</SUB> is hyponormal; (ii)ker[T<SUB>Φ</SUB><SUP>@?</SUP>,T<SUB>Φ</SUB>] is invariant for T<SUB>Φ</SUB>, then T<SUB>Φ</SUB> is normal. Hence in particular, if T<SUB>Φ</SUB> is subnormal then T<SUB>Φ</SUB> is normal. Next, we show that every pure quasinormal Toeplitz operator with a matrix-valued rational symbol is unitarily equivalent to an analytic Toeplitz operator.