Electrical and Thermal Characteristics of the Insulator-Metal Transition in Crystalline $$\hbox {V}_{2}\hbox {O}_{5}$$ V 2 O 5 Films

Kang, Manil,Kim, Sok Won Plenum Press 2017 International journal of thermophysics Vol.38 No.10

Neural correlates of bridging inferences and coherence processing.

Kim, Sung-il,Yoon, Misun,Kim, Wonsik,Lee, Sunyoung,Kang, Eunjoo Plenum Press 2012 JOURNAL OF PSYCHOLINGUISTIC RESEARCH Vol.41 No.4

<P>We explored the neural correlates of bridging inferences and coherence processing during story comprehension using Positron Emission Tomography (PET). Ten healthy right-handed volunteers were visually presented three types of stories (Strong Coherence, Weak Coherence, and Control) consisted of three sentences. The causal connectedness among sentences in the Strong Coherence story was strong that readers would not have to generate bridging inferences, whereas the causal antecedent of the last sentence in the Weak Coherence story was not explicitly stated so that readers should draw bridging inferences to fill the gap between sentences. It was found that the left middle temporal gyrus was activated while participants read the Weak Coherence stories. In contrast, the dorsomedial prefrontal cortex (dmPFC) and posterior cingulate cortex were activated only in the Strong Coherence condition. This suggests that the dmPFC was involved in coherence processing whereas bridging inference was mediated by the left middle temporal gyrus. It was also found that anterior temporal pole and the temporo-parietal junction mediated general semantic processing.</P>

Silver nanoparticle-enhanced chemiluminescence method for determining naproxen based on europium(III)-sensitized Ce(IV)-Na2S2O4 reaction.

Kamruzzaman, Mohammad,Alam, Al-Mahmnur,Kim, Kyung Min,Lee, Sang Hak,Kim, Young Ho,Kim, Sung Hong Plenum Press ; Springer 2012 Journal of fluorescence Vol.22 No.3

<P>A simple and sensitive chemiluminescence (CL) method coupled with flow-injection technique is proposed to determine naproxen (NAP). The method is based upon the enhancement of the weak CL signal arising from the reaction of Ce(IV) and Na(2)S(2)O(4) with Eu(3+) to form the Eu(3+)-Ce(IV)-Na(2)S(2)O(4) system. The CL intensity was significantly increased by the introduction of NAP into this system in the presence of silver nanoparticles (Ag NPs). Examination of the recorded UV-vis spectra and fluorescence spectra indicated that the energy of the intermediate SO(2)*, which originated from the redox reaction of Ce(IV) and Na(2)S(2)O(4), was transferred to Eu(3+) via NAP and that the process was accelerated by Ag NPs due to their catalytic activity. Under the optimum conditions, the CL intensity was increased with increasing NAP concentration and the correlation was linear (r = 0.9992) over the NAP concentration range of 1-420 ng mL(-1). The limit of detection (LOD) was 0.11 ng mL(-1) with a relative standard deviation (RSD) of 1.15% for 5 replicate determinations of 200 ng mL(-1) NAP. The method was successfully applied to determine NAP in pharmaceutical and biological samples.</P>

A validated spectrofluorimetric method for the determination of citalopram in bulk and pharmaceutical preparations based on the measurement of the silver nanoparticles-enhanced fluorescence of citalopram/terbium complexes.

Khan, Muhammad Naeem,Shah, Jasmin,Jan, Muhammad Rasul,Lee, Sang Hak Plenum Press ; Springer 2013 Journal of fluorescence Vol.23 No.1

<P>A simple, sensitive, and accurate spectrofluorimetric method was developed for the determination of citalopram in bulk and pharmaceutical preparations. The method is based on the enhancement of the weak fluorescence signal (FL) of the Tb (III)-citalopram system in the presence of silver nanoparticles. Fluorescence intensities were measured at 555 nm after excitation at 281 nm. Prepared silver nanoparticles (AgNPs) were characterized by UV-Visible spectra and transmission electron microscopy (TEM). Various factors affecting the formation of citalopram-Tb (III)-AgNPs complexes were studied and optimized. The fluorescence intensity versus concentration plot was linear over the range 0.02-14 μg mL(-1), with an excellent correlation coefficient of 0.9978. The limit of detection (LOD) and limit of quantification (LOQ) were found to be 7.15 10(-6) μg mL(-1) and 2.38 10(-5) μg mL(-1) respectively. The proposed method was found to have good reproducibility with a relative standard deviation of 3.66% (n = 6). The interference effects of common excipients found in pharmaceutical preparations were studied. The developed method was validated statistically by performing recoveries studies and successfully applied for the assay of citalopram in bulk powder and pharmaceutical preparations. Percent recoveries were found to range from 98.98% to 100.97% for bulk powder and from 96.57% to 101.77% for pharmaceutical preparations.</P>

The role played by lipids unsaturation upon the membrane interaction of the Helicobacter pylori HP(2-20) antimicrobial peptide analogue HPA3.

Mereuta, Loredana,Luchian, Tudor,Park, Yoonkynung,Hahm, Kyung-Soo Plenum Press 2009 Journal of bioenergetics and biomembranes Vol.41 No.1

<P>The HPA3 peptide is an analogue of the linear antimicrobial peptide, HP(2-20), isolated from the N-terminal region of the Helicobacter pylori ribosomal protein, able to interact with zwitterionic lipid membranes and generate pores. Herein we focused on the importance of the degree of unsaturation of lipid acyl chains on HPA3 peptide-membrane interactions. Electrophysiology experiments carried out in reconstituted lipid membranes formed from phosphatidylcholines with one (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine - POPC) and two monounsaturated acyl chains (1,2-dioleoyl-sn-glycero-3-phosphocholine - DOPC) demonstrate that the lesser degree of the packing density of membrane lipids encountered in DOPC-based planar membranes greatly enhances the electric activity of pores created by the HPA3 peptide. Data derived from fluorescence spectroscopy experiments demonstrate that upon interaction with the bilayer, the HPA3 peptide translocates to the trans-side of the membrane. From the same experiments, we demonstrate that in the case of DOPC-based planar membranes, the net amount of HPA3 peptide which passes across the membrane and re-dissolves in the trans solution is almost 22% greater than POPC-based membranes. Such data further emphasize the modulatory role played by lipid acyl chain in determining antimicrobial peptides-lipids interactions, and demonstrate that small differences in unsaturation degree can impose a sizeable influence on HPA3 peptide activity.</P>

Persistence Length and Cooperativity Estimation of Single Stranded DNA using FCS Combined with HYDRO Program

Jung, S.,Lee, D.,Kim, S. W.,Kim, S. Y. Plenum Press 2017 JOURNAL OF FLUORESCENCE Vol.27 No.4

<P>Translational diffusion properties of single-stranded DNA (ssDNA) and G-quadruplexes were studied to determine the persistence length and cooperativity of G-quadruplex formation using FCS combined with HYDRO in which wormlike chain (WLC)-based Monte Carlo simulation are implemented. The presence of a guanine instead of a thymine shortened the contour length of nucleic acids and increased the vulnerability to ion screening. For cooperativity estimation, the telomeric sequence HT72 was assumed to undergo 27 intermediate states, which can be classified as ssDNA, single-G-quadruplex, double-G-quadruplex, and three consecutive G-quadruplexes. Each state type was modeled using a series of beads and appropriate bond lengths, which were obtained from the WLC model. Using the HYDRO program, we calculated diffusion times for each species, and these were used to calculate simulated HT72 diffusion times for mixtures of species in arbitrary KCl concentrations. By comparison between simulated and experimental diffusion properties, we obtained a positive cooperativity of C = 200 from FCS combined with HYDRO.</P>

Emergent Dynamics of a Generalized Lohe Model on Some Class of Lie Groups

Ha, Seung-Yeal,Ko, Dongnam,Ryoo, Sang Woo Plenum Press 2017 Journal of statistical physics Vol.168 No.1

<P>We introduce a Lohe group which is a new class of matrix Lie groups and present a continuous dynamical system for the synchronization of group elements in a Lohe group. The Lohe group includes classical Lie groups such as the orthogonal, unitary, and symplectic groups, and since Lohe groups need not be compact, global existence of ODEs may fail. The proposed dynamical system generalizes the Lohe model (Lohe in J Phys A 43:465301, 2010; Lohe in J Phys A 42:395101-395126, 2009) itself a nonabelian generalization of the Kuramoto model, and alongside we also generalize the analytical framework (Ha and Ryoo in J Stat Phys 163:411-439, 2016) of emergent and unique phase-locked states. For the construction of the phase-locked states, we introduce Lyapunov functions measuring the ensemble diameter and the dissimilarity between two Lohe flows, and derive Gronwall-type differential inequalities for them. The global existence of solutions then become a consequence of the boundedness of these Lyapunov functions. Our sufficient framework for the emergent dynamics is formulated in terms of coupling strength and initial states, and it leads to the global existence of solutions and the formation and uniqueness of a phase-locked asymptotic state. As a concrete example, we demonstrate how our theory can show emergent phenomenon on the Heisenberg group, where all initial configurations tend to a unique phase-locked state exponentially fast.</P>

In Vitro Biocidal Actions of <i>Rhus verniciflua</i> Bark Extract Wrapped Gold Nanoballs Against Biofilm-Forming Food-Borne Bacterial Pathogens

Vijayakumar, Sekar,Saravanakumar, Kandasamy,Hu, Xiaowen,Wang, Myeong-Hyeon Plenum Press 2019 Journal of cluster science Vol.30 No.6

<P> The research for innovative antibiofilm drugs is essential due to the increased microbial resistance to antibiotics presently in use. Now a day’s natural products wrapped nano biomaterial play an important role in the field of medicine. The aqueous bark extracts of <I>Rhus verniciflua</I> was used to synthesize gold nanoparticles (Rh-AuNPs) by green method. The synthesized nanoparticles were characterized (optical property, crystallinity, functional groups, size, shape and purity) by UV-vis spectroscopy (UV), X-ray diffraction (XRD), Fourier transform infrared (FTIR), Field emission transmission electron microscopy (FE-TEM) with Energy dispersive X-ray (EDX). An effective antioxidant activity was observed at 100 μg/ml of Rh AuNPs. The acridine orange, live and dead (PI-SYTO-9) staining assay using confocal laser scanning microscopic, results evidanced that the Rh-AuNPs (100 μg/ml) was effectively inhibited the biofilms of <I>Escherichia coli</I> and <I>Staphylococcus aureus.</I> In addition, Rh-AuNPs also significantly inhibited the cell surface hydrophobicity of both <I>E. coli</I> and <I>S. aureus</I> at 100 μg/ml. This study reports antibacterial potency of Rh-AuNPs and that have significant therapeutic properties. </P>

Syllable transposition effects in korean word recognition.

Lee, Chang H,Kwon, Youan,Kim, Kyungil,Rastle, Kathleen Plenum Press 2015 JOURNAL OF PSYCHOLINGUISTIC RESEARCH Vol.44 No.3

<P>Research on the impact of letter transpositions in visual word recognition has yielded important clues about the nature of orthographic representations. This study investigated the impact of syllable transpositions on the recognition of Korean multisyllabic words. Results showed that rejection latencies in visual lexical decision for syllable-transposed Korean nonwords were delayed as compared with matched Korean nonwords without syllable transpositions. These findings bolster the case that the syllable provides an important functional unit in Korean word recognition, and suggest a degree of position invariance in syllable representations.</P>

Mitochondria in relation to cancer metastasis.

Bhandary, Bidur,Marahatta, Anu,Kim, Hyung-Ryong,Chae, Han-Jung Plenum Press 2012 Journal of bioenergetics and biomembranes Vol.44 No.6

<P>Mitochondria, also known as 'Power House of cell,' are crucial organelles, regulating energy metabolism. Recently, an involvement of mitochondria in cancer occurrence and metastasis has been proposed. The roles of mitochondria in cancer progression/metastasis include alteration of glycolysis, regulation of ROS and suppression of intrinsic apoptosis. This mini-review explains the specific mitochondrial characteristics during cancer metastasis with past and recent findings. It may contribute to understanding mitochondria-related mechanisms of cancer metastasis.</P>