Structural dynamics of keyword networks: Liquid crystal display and plasma display panel cases

Yang, H.,Jung, W.S. Elsevier Science Publishers 2016 Journal of Engineering and Technology Management Vol.40 No.-

<P>This study focuses on understanding scientific evolution by using keyword co-occurrence networks, where keywords appearing in a scientific article are linked with a weight equal to the number of co-occurrences. To characterize structural changes of the network, we examine distributions of sums of weights by node over time. In particular, a change of power-law behavior is utilized to explore scientific evolution, such as emerging scientific paradigms and advancing normal science. As an illustration of the method used, the development of Liquid Crystal Displays (LCDs) and Plasma Display Panels (PDPs) is tracked. We detect two-tiered power-law distributions in the initial stage of scientific growth in both technologies due to differences in research intensity between two groups. The groups of keywords more likely to attract researchers' interest than others are incrementally developed until the mid-2000s to overtake those prior. Finally, we can capture a merging point of the dichotomous structure of PDPs but LCDs maintain the structural separation throughout the adjustment area. We expect that this structural investigation of keyword co-occurrence networks provides an indicator to diagnose the research evolution in that field. (C) 2016 Published by Elsevier B.V.</P>

Identification of body fluid-specific DNA methylation markers for use in forensic science

Park, J.L.,Kwon, O.H.,Kim, J.H.,Yoo, H.S.,Lee, H.C.,Woo, K.M.,Kim, S.Y.,Lee, S.H.,Kim, Y.S. Elsevier Science 2014 FORENSIC SCIENCE INTERNATIONAL GENETICS Vol.13 No.-

DNA methylation, which occurs at the 5'-position of the cytosine in CpG dinucleotides, has great potential for forensic identification of body fluids, because tissue-specific patterns of DNA methylation have been demonstrated, and DNA is less prone to degradation than proteins or RNA. Previous studies have reported several body fluid-specific DNA methylation markers, but DNA methylation differences are sometimes low in saliva and vaginal secretions. Moreover, specific DNA methylation markers in four types of body fluids (blood, saliva, semen, and vaginal secretions) have not been investigated with genome-wide profiling. Here, we investigated novel DNA methylation markers for identification of body fluids for use in forensic science using the Illumina HumanMethylation 450K bead array, which contains over 450,000 CpG sites. Using methylome data from 16 samples of blood, saliva, semen, and vaginal secretions, we first selected 2986 hypermethylated or hypomethylated regions that were specific for each type of body fluid. We then selected eight CpG sites as novel, forensically relevant DNA methylation markers: cg06379435 and cg08792630 for blood, cg26107890 and cg20691722 for saliva, cg23521140 and cg17610929 for semen, and cg01774894 and cg14991487 for vaginal secretions. These eight selected markers were evaluated in 80 body fluid samples using pyrosequencing, and all showed high sensitivity and specificity for identification of the target body fluid. We suggest that these eight DNA methylation markers may be good candidates for developing an effective molecular assay for identification of body fluids in forensic science.

Parasitic robot system for waypoint navigation of turtle

Kim, Dae-Gun,Lee, Serin,Kim, Cheol-Hu,Jo, Sungho,Lee, Phill-Seung Elsevier Science B.V., Amsterdam 2017 JOURNAL OF BIONICS ENGINEERING Vol.14 No.2

<P>In research on small mobile robots and biomimetic robots, locomotion ability remains a major issue despite many advances in technology. However, evolution has led to there being many real animals capable of excellent locomotion. This paper presents a 'parasitic robot system' whereby locomotion abilities of an animal are applied to a robot task. We chose a turtle as our first host animal and designed a parasitic robot that can perform 'operant conditioning'. The parasitic robot, which is attached to the turtle, can induce object-tracking behavior of the turtle toward a Light Emitting Diode (LED) and positively reinforce the behavior through repeated stimulus-response interaction. After training sessions over five weeks, the robot could successfully control the direction of movement of the trained turtles in the waypoint navigation task. This hybrid animal-robot interaction system could provide an alternative solution to some of the limitations of conventional mobile robot systems in various fields, and could also act as a useful interaction system for the behavioral sciences.</P>

Orbital hybridization mechanism for the enhanced photoluminescence in edge-functionalized sp² carbon clusters

Kang, B.,Choi, Y.,Kim, B.S.,Youn, I.S.,Lee, G. Pergamon Press ; Elsevier Science Ltd 2016 Carbon Vol.109 No.-

<P>Using the first principles methods, we performed systematic study on the effect of edge-functional groups on the electronic energy levels and the optical properties of sp(2) carbon clusters. It is found that the intrinsic pi and pi* orbitals are weakly altered by oxygen-bearing functional groups, but it is significantly disrupted by pyrrolic groups. Thereby the oscillator strength of the lowest-energy transition is found to be much stronger for the pyrrolic group functionalized cluster than for the carboxyl group. From our results being consistent with the experimental reports, we suggest that the photoluminescence enhancement is caused by a perturbation of the intrinsic, frontier molecular orbitals by edge groups. (C) 2016 Elsevier. Ltd. All rights reserved.</P>

Effects of the degree of polymerization on the structure of sodium silicate and aluminosilicate glasses and melts: An ¹⁷O NMR study

Lee, S.K.,Stebbins, J.F. Pergamon Press ; Elsevier Science Ltd 2009 Geochimica et cosmochimica acta Vol.73 No.4

Revealing the atomic structure and disorder in oxide glasses, including sodium silicates and aluminosilicates, with varying degrees of polymerization, is a challenging problem in high-temperature geochemistry as well as glass science. Here, we report <SUP>17</SUP>O MAS and 3QMAS NMR spectra for binary sodium silicate and ternary sodium aluminosilicate glasses with varying degrees of polymerization (Na<SUB>2</SUB>O/SiO<SUB>2</SUB> ratio and Na<SUB>2</SUB>O/Al<SUB>2</SUB>O<SUB>3</SUB> ratio), revealing in detail the extent of disorder (network connectivity and topological disorder) and variations of NMR parameters with the glass composition. In binary sodium silicate glasses [Na<SUB>2</SUB>O-k(SiO<SUB>2</SUB>)], the fraction of non-bridging oxygens (NBOs, Na-O-Si) increases with the Na<SUB>2</SUB>O/SiO<SUB>2</SUB> ratio (k), as predicted from the composition. The <SUP>17</SUP>O isotropic chemical shifts (<SUP>17</SUP>O δ<SUB>iso</SUB>) for both bridging oxygen (BO) and NBO increase by about 10-15ppm with the SiO<SUB>2</SUB> content (for k=1-3). The quadrupolar coupling products of BOs and NBOs also increase with the SiO<SUB>2</SUB> content. These trends suggest that both NBOs and BOs strongly interact with Na; therefore, the Na distributions around BOs and NBOs are likely to be relatively homogenous for the glass compositions studied here, placing some qualitative limits on the extent of segregation of alkali channels from silica-enriched regions as suggested by modified random-network models. The peak width (in the isotropic dimension) and thus bond angle and length distributions of Si-O-Si and Na-O-Si increase with the SiO<SUB>2</SUB> content, indicating an increase in the topological disorder with the degree of polymerization. In the ternary aluminosilicate glasses [Na<SUB>2</SUB>O]<SUB>x</SUB>[Al<SUB>2</SUB>O<SUB>3</SUB>]<SUB>1-x</SUB>SiO<SUB>2</SUB>, the NBO fraction decreases while the Al-O-Si and Al-O-Al fractions apparently increase with increasing Al<SUB>2</SUB>O<SUB>3</SUB> content. The variation of oxygen cluster populations suggests that deviation from ''Al avoidance'' is more apparent near the charge-balanced join (Na/Al=1). The Si-O-Si fraction, which is closely related to the activity coefficient of silica, would decrease with increasing Al<SUB>2</SUB>O<SUB>3</SUB> content at a constant mole fraction of SiO<SUB>2</SUB>. Therefore, the activity of silica may decrease from depolymerized binary silicates to fully polymerized sodium aluminosilicate glasses at a constant mole fraction of SiO<SUB>2</SUB>.

A combined treatment of UV-assisted TiO₂ photocatalysis and high hydrostatic pressure to inactivate internalized murine norovirus

Kim, S.H.,Shahbaz, H.M.,Park, D.,Chun, S.,Lee, W.,Oh, J.W.,Lee, D.U.,Park, J. Elsevier Science 2017 Innovative food science & emerging technologies Vol.39 No.-

<P>Industrial relevance: HHP treatment of raw oysters has proved commercially successful, but there is a less evidence available regarding the potential of HHP for inactivation of localized viruses present inside foods. A sequential combination of UV-assisted TiO2 photocatalysis (UVTP) and high hydrostatic pressure (HHP) achieved significantly higher inactivation of localized virus compared to individual treatments due to a synergistic mechanism. An experimentally prepared model food system was found useful to simulate foods with morphological variations and unpredictable viral internalization patterns. This UVTP-HHP combined treatment for inactivation of localized MNV-1 can be useful for disinfection of raw oysters and other similar foods. (C) 2016 Elsevier Ltd. All rights reserved.</P>

The present status and analysis of Science & Technology Information (STI) service policy in Korea

Yun-Seok, L.,jae-sung, K. JAI Press ; Elsevier Science Ltd 2009 Government information quarterly Vol.26 No.3

National Science & Technology Information (STI) infrastructure of Korea has been independently developed as a decentralized system within the government ministry. In order to effectively establish the national STI infrastructure, it is essential to create a networked and integrated system in the domestic and foreign information infrastructure. This study aims to analyze current national STI infrastructure and to suggest specific ways in which domestic and foreign STI infrastructure may be utilized.

WITHDRAWN: Spectroscopic characterization of selected functionalized fullerenes - IR absorption and Raman scattering studies

Lewandowska, K.,Barszcz, B.,Graja, A.,Nam, S.Y.,Han, Y.S.,Kim, T.D.,Lee, K.S. Elsevier Science Publishers 2014 Materials chemistry and physics Vol.148 No.3

The Publisher regrets that this article is an accidental duplication of an article that has already been published in <Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 118, (2014) 204 - 209>, http://dx.doi.org/<10.1016/j.saa.2013.08.102>. The duplicate article has therefore been withdrawn. The full Elsevier Policy on Article Withdrawal can be found at http://www.elsevier.com/locate/withdrawalpolicy.

Tranexamic acid inhibits melanogenesis by activating the autophagy system in cultured melanoma cells

Cho, Y.H.,Park, J.E.,Lim, D.S.,Lee, J.S. Elsevier ; Elsevier Science Pub. Co 2017 JOURNAL OF DERMATOLOGICAL SCIENCE Vol.88 No.1

Background: As interest in skin beauty increases, the development of new skin whitening agents has attracted substantial attention; however, the action mechanism of the agents developed so far remains largely unknown. Tranexamic acid (TXA) is commonly being used to reduce melanin synthesis in patients with melasma and also used as a raw material for functional whitening cosmetics, although its action mechanism is poorly understood. Autophagy has been well known to be essential for tissue homeostasis, adaptation to starvation, and removal of dysfunctional organelles or pathogens. Recent studies have shown that autophagy regulators might have prominent roles in the initial formation stage of the melanosome, a lysosome-related organelle synthesizing melanin pigments. However, there is still no direct evidence showing a relationship between the activation of the autophagy system and the melanogenesis. Objective: To investigate whether TXA can inhibit melanogenesis through the activation of autophagy in a melanoma cell line. Methods: B16-F1 melanoma cells were treated with TXA and the levels of autophagy- and melanogenesis-related proteins were determined by Western blottings. The direct effect of TXA-mediated autophagy activation on melanin production was further evaluated by transfecting the cells with 60 pmols of small interfering RNAs (siRNAs)-targeting the mechanistic target of rapamycin (mTOR) and the autophagy-related protein 5 (Atg5). Results: The results of Western blottings showed that TXA enhanced the production of autophagy-related proteins such as mitogen-activated protein kinases (MAPKs), extracellular signal-regulated kinase (ERK)½, Beclin-1, Atg12, and light chain 3 (LC3) I-II, whereas it decreased the synthesis of the mTOR complex. Confocal microscopy clearly showed that TXA treatment resulted in the formation of autophagosomes in B16-F1 cells, as revealed by immunostaining with an anti-LC3 antibody. The production of melanogenesis-associated proteins, including microphthalmia-associated transcription factor (MITF), tyrosinase, and tyrosinase-related protein 1 and 2 (TRP½), were clearly downregulated by the treatments with TXA. These results suggest that TXA can mediate a decrease in melanin synthesis by alleviating the production of tyrosinase and TRP½, along with lowered MITF protein levels. Furthermore, after treatment with TXA, siRNAs- targeting to mTOR and Atg5 increased melanin synthesis by 20% and 40%, respectively, compared to that in non-transfected cells, in a dose-dependent manner. These results further confirmed that TXA can inhibit melanogenesis by activating the autophagy system. Conclusion: Collectively, the results demonstrate that TXA can reduce melanin synthesis in melanoma B16-F1 cells by activating the ERK signaling pathway and the autophagy system.

Two stage deformation modeling for DP 780 steel sheet using crystal plasticity

Verma, R. K.,Biswas, P.,Kuwabara, T.,Chung, K. Elsevier Science B.V., Amsterdam. 2014 Materials science & engineering. properties, micro Vol.604 No.-

Proper analysis of non-proportional plastic deformation is important for the successful prediction of failure and springback in sheet metal forming of ultra-high strength steels. In this work, a crystal plasticity finite element was applied to analyze the two-stage deformation behavior of a dual phase (DP 780) steel. It was found to be possible to predict the cross-effect observed during the two-stage deformation fairly accurately using the model. It was further felt that accounting for the path dependency of dislocation evolution would still improve the simulation accuracy. (C) 2014 Elsevier B.V. All rights reserved.