Fishing Jacket

Youngah Kwon(권영아) 한국디자인학회 2020 한국디자인학회 국제초대전도록 Vol.2020 No.11

Complexation dynamics of CH₃SCN and Li⁺ in acetonitrile studied by two-dimensional infrared spectroscopy

Kwon, YoungAh,Park, Sungnam The Royal Society of Chemistry 2015 Physical chemistry chemical physics Vol.17 No.37

<P>Ion–molecule complexation dynamics were studied with CH<SUB>3</SUB>SCN and Li<SUP>+</SUP> in acetonitrile by vibrationally probing the nitrile stretching vibration of CH<SUB>3</SUB>SCN. The nitrile stretching vibration of CH<SUB>3</SUB>SCN has a long lifetime (<I>T</I><SUB>1</SUB> = ∼90 ps) and its frequency is significantly blue-shifted when CH<SUB>3</SUB>SCN is bound with Li<SUP>+</SUP> ions to form a CH<SUB>3</SUB>SCN⋯Li<SUP>+</SUP> complex in acetonitrile. Such spectral properties enable us to distinguish free CH<SUB>3</SUB>SCN and the CH<SUB>3</SUB>SCN⋯Li<SUP>+</SUP> complex in solutions and measure their dynamics occurring on hundred picosecond timescales. For the complexation between CH<SUB>3</SUB>SCN and Li<SUP>+</SUP> in acetonitrile, the change in enthalpy (Δ<I>H</I> = −7.17 kJ mol<SUP>−1</SUP>) and the change in entropy (Δ<I>S</I> = −34.4 J K<SUP>−1</SUP> mol<SUP>−1</SUP>) were determined by temperature-dependent FTIR experiments. Polarization-controlled infrared pump–probe (IR PP) spectroscopy was used to measure the population decay and orientational dynamics of free CH<SUB>3</SUB>SCN and the CH<SUB>3</SUB>SCN⋯Li<SUP>+</SUP> complex. Especially, the orientational relaxation of the CH<SUB>3</SUB>SCN⋯Li<SUP>+</SUP> complex was found to be almost 3 times slower than those of free CH<SUB>3</SUB>SCN because Li<SUP>+</SUP> ions strongly interact with the neighboring solvents. Most importantly, the complexation dynamics of CH<SUB>3</SUB>SCN and Li<SUP>+</SUP> in acetonitrile were successfully measured in real time by 2DIR spectroscopy for the first time and the dissociation and association time constants were directly determined by using the two-species exchange kinetic model. Our experimental results provide a comprehensive overview of the ion–molecule complexation dynamics in solutions occurring under thermal equilibrium conditions.</P> <P>Graphic Abstract</P><P>A chemical exchange 2DIR study of ion–molecule complexation dynamics in electrolyte solutions. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c5cp02833g'> </P>

Glass Particles II

권영아 (Youngah Kwon) 한국디자인학회 2016 한국디자인학회 국제초대전도록 Vol.2016 No.12

Fractal Particles I

권영아(Youngah Kwon) 한국디자인학회 2015 한국디자인학회 국제초대전도록 Vol.2015 No.10

Fractal Pattern X

권영아(Youngah Kwon) 한국디자인학회 2017 한국디자인학회 국제초대전도록 Vol.2017 No.12

Storage capacity of a committee machine with an overlapping hidden layer

Kwon, Chulan,Park, Youngah 명지대학교 자연과학연구소 1996 자연과학논문집 Vol.13 No.-

We present theoretical investigations of storage capacity of a committee machine that has an overlapping hidden layer. Because of the complicated architecture of the hidden layer, correlations of weights between different hidden units are important, unlikely for networks with a non-overlapping hidden layer, and exact calculation for large number M of hidden units using the replica theory has not been fulfilled. It is the difficulty in handling many order parameters comes from the permutation symmetry breaking and the replica symmetry breaking. In this paper we derive useful relations among order parameters that diminishes crucially the difficulty in determining all order parameters. We examine both the case of binary weights and the case of continuous weights.

Effects of genetic variations in NRG1 on cognitive domains in patients with schizophrenia and healthy individuals

Cho, Youngah,Ryu, Seunghyong,Huh, Iksoo,Cho, Eun Young,Oh, Hyeji,Lee, Yu-Sang,Lee, Woo Kyeong,Park, Taesung,Kwon, Jun Soo,Hong, Kyung Sue RAPID COMMUNICATIONS OF OXFORD LTD 2015 PSYCHIATRIC GENETICS Vol.25 No.4

BACKGROUND: The neuregulin 1 (NRG1) gene has been investigated as a candidate susceptibility gene for schizophrenia. A number of studies have also explored the genetic effect of NRG1 on cognitive deficits related to schizophrenia, and thus far generated inconsistent results. The current study aimed to determine whether genetic variations in NRG1 are associated with cognitive domains in schizophrenic patients and healthy individuals. MATERIALS AND METHODS: Comprehensive neuropsychological tests composed of six cognitive domains were administered to 135 clinically stable patients with schizophrenia and 119 healthy individuals. On the basis of previous reports of positive association, a total of four single nucleotide polymorphisms were analyzed. In testing the genotype effect on cognitive domains, we used repeated-measure analysis for six cognitive domain scores of each individual as repeated measurements. RESULTS: An association of P-value less than 0.05 with at least one cognitive domain in patients and/or healthy individuals was observed for all of the single nucleotide polymorphisms. After applying the correction for multiple testing, the association remained statistically significant between rs6994992 and general cognitive ability (g) in the patient group and between rs2439272 and the ‘working memory’ domain in the group of healthy participants. CONCLUSION: This study suggests the involvement of NRG1 in the susceptibility for developing cognitive deficits in schizophrenic patients. For some cognitive domains, its genetic effect was also significant in generating interindividual variability within the normal functional range.

A new-mixed(flat-glass) phase in randomly polymerized membranes

Park, Youngah,Kwon, Chulan 명지대학교 자연과학연구소 1996 자연과학논문집 Vol.13 No.-

We study polymerized membrane with quenched disorder in the internal metric within the mean field approximation. We find a new mixed (flat-glass) phase, from the stability analysis of the replica-symmetric solution. This new phase is the frozen phase with a non-zero average tangent field but with broken replica-symmetry, which may correspond to the observed wrinkled phase of partially polymerized membrane.

Overexpression of Cell Cycle Proteins of Peripheral Lymphocytes in Patients with Alzheimer’s Disease

Hyeran Kim,YoungAh Kwon,InnSook Ahn,Sangha Kim,Seonwoo Kim,Sangmee Ahn Jo,DohKwan Kim 대한신경정신의학회 2016 PSYCHIATRY INVESTIGATION Vol.13 No.1

Objective-Biological markers for Alzheimer’s disease (AD) will help clinicians make objective diagnoses early during the course of dementia. Previous studies have suggested that cell cycle dysregulation begins earlier than the onset of clinical manifestations in AD. Methods-We examined the lymphocyte expression of cell cycle proteins in AD patients, dementia controls (DC), and normal controls (NC). One-hundred seventeen subjects (36 AD, 31 DC, and 50 NC) were recruited. The cell cycle proteins CDK2, CDK4, CDK6, cyclin B, and cyclin D were measured in peripheral lymphocytes. Cell cycle protein expression in the three groups was compared after adjusting for age and sex. Results-The levels of cell cycle proteins CDK2, CDK4, CDK6, cyclin B, and cyclin D were significantly higher in AD patients than in the NC subjects. The DC group manifested intermediate levels of cell cycle proteins compared with the AD patients and the NC subjects. The present study indicates that cell cycle proteins are upregulated in the peripheral lymphocytes of AD patients. Conclusion-Cell cycle dysregulation in peripheral lymphocytes may present a promising starting point for identifying peripheral biomarkers of AD.

Rotational Dynamics of Metal Azide Ion Pairs in Dimethylsulfoxide Solutions

Son, Hyewon,Kwon, YoungAh,Kim, Jinwoo,Park, Sungnam American Chemical Society 2013 The journal of physical chemistry. B, Condensed ma Vol.117 No.9

<P>Azide ion is an excellent vibrational probe for studying ion–ion and ion–dipole interactions in solutions because its frequency is sensitively dependent on its local environments. When azide ion forms contact ion pairs with cations in dimethylsulfoxide (DMSO), free azide ion and contact ion pairs are spectrally well distinguished in FTIR spectra. Here, we investigated vibrational population relaxation, <I>P</I>(<I>t</I>), and orientational relaxation dynamics, <I>r</I>(<I>t</I>), of free azide ion and contact ion pairs (LiN<SUB>3</SUB>, NaN<SUB>3</SUB>, NH<SUB>4</SUB>N<SUB>3</SUB>, MgN<SUB>3</SUB><SUP>+</SUP>, and CaN<SUB>3</SUB><SUP>+</SUP>) in DMSO by IR pump–probe spectroscopy. For metal azide ion pairs, the metal ion slowed down the vibrational relaxation of azide ion by acting like a thermal insulator. Biexponential behavior of <I>r</I>(<I>t</I>) was analyzed in the wobbling-in-a-cone model. The long time component of <I>r</I>(<I>t</I>) of free azide ion was found to be viscosity-dependent. The wobbling motion of azide ion within the frame of metal azide ion pairs was weakly dependent on the countercation. When the overall orientational relaxation of metal azide ion pairs was analyzed by the extended Debye–Stokes–Einstein equation, it was well described under stick or superstick boundary conditions due to a strong interaction between the metal ion and DMSO molecules. Our experimental results provide important insight in understanding the rotational dynamics of small ionic species in polar solvents when the size of the ionic species is smaller than or comparable to that of the solvent molecule.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jpcbfk/2013/jpcbfk.2013.117.issue-9/jp312055f/production/images/medium/jp-2012-12055f_0006.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/jp312055f'>ACS Electronic Supporting Info</A></P>