• Title/Summary/Keyword: Single-molecule

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A Theoretical Study of CO Molecules on Metal Surfaces: Coverage Dependent Properties

  • Sang -H. Park;Hojing Kim
    • Bulletin of the Korean Chemical Society
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    • v.12 no.5
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    • pp.574-582
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    • 1991
  • The CO molecules adsorbed on Ni(111) surface is studied in the cluster approximation employing EH method with self-consistent charge iteration. The effect of CO coverage is simulated by allowing the variation of valence state ionization potentials of each Ni atom in model cluster according to the self-consistent charge iteration method. The CO coverage dependent C-O stretching frequency shift, adsorption site conversion, and metal work function change are attributed to the charge transfer between metal surface and adsorbate. For CO/Ni(111) system, net charge transfer from Ni surface to chemisorbed CO molecules makes surface Ni atoms be more positive with increasing coverage, and lowers Ni surface valence band. This leads to a weaker interaction between metal surface valence band and Co $2{\pi}^{\ast}$ MO, less charge transfer to a single CO molecule, and the bule shift of C-O stretching frequency. Further increase of coverage induces the conversion of 3-fold site CO to lower coordination site CO as well as the blue shift of C-O stretching frequency. This whole process is accompanied by the continuous increase of metal work function.

The Crystal Structure of Cinmetacin ($C_{21}H_{19}NO_4$), A Non-steroidal Antiinflammatory Agent

  • Kim, Yang-Bae;Park, Il-Yeong;Park, Yang-Hwan
    • Archives of Pharmacal Research
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    • v.12 no.1
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    • pp.52-57
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    • 1989
  • The structure of cinmetacin was determined by single crystal X-ray diffraction analysis. The compound was recrystallized from a mixture of acetone and water in orthorhombic, space group $P2_12_12_1$, with Z=4, a=35.681(8), b=9.482(2), c:5.071(1) ${\AA}$, $D_x=1.352 g/cm^3$, and $D_m=1.35g/cm^3$. The structure was solved by direct method and refined by least-squares procedure to the final R value of 0.036 for 1441 observed reflections ($F{\geq}3{\sigma}(F)$). The carboxyl group of the molecule is nearly perpendicular to the indole ring. The dihedral angle between indole ring and phenyl group is $64.5^{\circ}$. The molecules are linked together via O(1)-H ----O(3) hydrogen bonds, and arranged along 2-fold screw axis in the crystal. The intermolecular contacts are the normal van der Waals' forces.

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The Structure and Ab Initio Studies of Thiourea Dioxide

  • 송진수;김은희;강성권;윤석성;서일환;최성산;이삼근;William P. Jensen
    • Bulletin of the Korean Chemical Society
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    • v.17 no.2
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    • pp.201-205
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    • 1996
  • The crystal and molecular structure of thiourea dioxide, (NH2)2CSO2, was determined by x-ray single crystal diffraction techniques. Lattice constants are a=10.669(2), b=10.119(2), and c=3.9151(5) Å with the space group Pnma and Z=4. The thiourea portion of the molecule has a planar conformation. When the two oxygen atoms are included, the sulfur atom is at the apex of a trigonal pyramid formed with the two oxygen atoms and the carbon atom as the base. The crystal structure is stabilized by strong intermolecular hydrogen bonds. Ab initio calculations were performed to investigate the bonding features and reactivity of thiourea dioxide. The calculated bond order of S-C is only 0.481. The hydrogen bond energy was computed to be 22.3 kcal/mol for dimer. MEP analysis reveals that the sites on nucleophilic reactions are S and C atoms.

Draft Genome Sequence of the White-Rot Fungus Schizophyllum Commune IUM1114-SS01

  • Kim, Da-Woon;Nam, Junhyeok;Nguyen, Ha Thi Kim;Lee, Jiwon;Choi, Yongjun;Choi, Jaehyuk
    • Mycobiology
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    • v.49 no.1
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    • pp.86-88
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    • 2021
  • The monokaryotic strain, Schizophyllum commune strain IUM1114-SS01, was generated from a basidiospore of dikaryotic parental strain IUM1114. It even showed the decolorizing activities for several textile dyes much better than its parental strain. Based on the results of a single-molecule real-time sequencing technology, we present the draft genome of S. commune IUM1114-SS01, comprising 41.1 Mb with GC contents of the genome were 57.44%. Among 13,380 protein-coding genes, 534 genes are carbon hydrate-active enzyme coding genes.

Acute Testis Toxicity of Bisphenol A Diglycidyl Ether in Sprague-Dawley Rats

  • Yang, Yun-Jung;Lee, Shin-Young;Kim, Kyung-Yong;Hong, Yeon-Pyo
    • Journal of Preventive Medicine and Public Health
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    • v.43 no.2
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    • pp.131-137
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    • 2010
  • Objectives: Bisphenol A diglycidyl ether (BADGE) is a liquid compound obtained by condensation of two molecules of epichlorohydrin with one molecule of bisphenol A. General and reproductive toxicity with BADGE has been reported higher than 1000 mg/kg/day. This study was performed to show the effects of acute exposure to BADGE below 1000 mg/kg/day on the testis in adult male rats. Methods: BADGE was administered by gastric lavage in a single dose of 500, 750, 1000, and 2000 mg/kg/day in 8-week old male SPF Sprague-Dawley rats. The right testis was processed for light microscopic analysis. The left testis was homogenized and spermatids were counted to determine the daily sperm production and daily abnormal sperm production. The sperm count, sperm motility, and incidence of abnormal sperm were estimated in the epididymis. In testicular sections, the seminiferous tubules were observed for qualitative changes. The progression of spermatogenesis was arbitrarily classified as full-matured, maturing, and immature. The specimen slide was observed at 3 points and 10 seminiferous tubules were evaluated at each point. Results: The male rats exposed to single oral dose of BADGE at 750, 1000, and 2000 mg/kg/day were significantly increased the number of immature and maturing sperm on the testis. There were no significant differences with respect to sperm head count, sperm motility, and sperm abnormality in the BADGE treatment groups. Conclusions: These results suggest that single oral exposure of BADGE 750 mg/kg/day can affect adult male testis development.

Expression and Characterization of a Single-Chain Variable Fragment against Human LOX-1 in Escherichia coli and Brevibacillus choshinensis

  • Hu, Wei;Xiang, Jun-Yan;Kong, Ping;Liu, Ling;Xie, Qiuhong;Xiang, Hongyu
    • Journal of Microbiology and Biotechnology
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    • v.27 no.5
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    • pp.965-974
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    • 2017
  • The single-chain variable fragment (scFv) against lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) is a promising molecule for its potential use in the diagnosis and immunotherapy of atherosclerosis. Producing this scFv in several milligram amounts could be the starting point for further engineering and application of the scFv. In this study, the abundant expression of the anti-LOX-1 scFv was attempted using Escherichia coli (E. coli) and Brevibacillus choshinensis (B. choshinensis). The scFv had limited soluble yield in E. coli, but it was efficiently secreted by B. choshinensis. The optimized fermentation was determined using the Plackett-Burman screening design and response surface methodology, under which the yield reached up to 1.5 g/l in a 5-L fermentor. Moreover, the properties of the scFvs obtained from the two expression systems were different. The antigen affinity, transition temperature, and particle diameter size were 1.01E-07 M, $55.2{\pm}0.3^{\circ}C$, and 9.388 nm for the scFv expressed by B. choshinensis, and 4.53E-07 M, $52.5{\pm}0.3^{\circ}C$, and 13.54 nm for the scFv expressed by E. coli. This study established an efficient scale-up production methodology for the anti-LOX-1 scFv, which will boost its use in LOX-1-based therapy.

Function of the Tethered rec-eCG in Rat and Equine Receptors

  • Park, Jong-Ju;Jargal, Naidansuren;Yoon, Jong-Taek;Min, Kwan-Sik
    • Reproductive and Developmental Biology
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    • v.33 no.4
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    • pp.229-236
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    • 2009
  • The glycoprotein hormone family represents a class of heterodimers, that includes the placental hormone equine chorionic gonadotropin (eCG) and the anterior pituitary hormones- follitropin (FSH), lutropin (LH), and thyrotropin (TSH). The 4 hormones are heterodimers, with a common $\alpha$-subunit and unique $\beta$-subunits. eCG is the most heavily glycosylated of the known pituitary and placental glycoprotein hormones. Recent observations using single chain glycoprotein hormone analogs in which, the $\beta$-and $\alpha$-subunits are linked, implied that heterodimeric-like quaternary configuration is not a prerequisite for receptor/signal transduction. To study the function and signal transduction of tethered rec-eCG, a single chain eCG molecule was constructed and rec-eCG protein was produced. Molecular mass of the single chain is about 45 kDa. All mice were ovulated by tethered rec-eCG treatment. The dual activity of tethered rec-eCG was determined in receptor cell lines of nonequid species; in fact, this dual activity was proven in species other than horse. Tethered rec-eCG in equids does not bind to FSH receptors, suggesting that eCG is primarily an LH-like hormone in the horse. Taken together, these data suggest that tethered rec-eCG has dual activity in nonequid species in vitro. However, it has only LH-like activity in equid species in vitro.

Structure analysis, and magnetic study of a new Gd-metal-organic framework single crystal grown by the slow-evaporation method (증발법으로 합성된 신규 가돌리늄 금속-유기골격체의 단결정 구조 분석 및 자성학적 특성 연구)

  • Song, Jeong Hwa
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.32 no.5
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    • pp.199-204
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    • 2022
  • A new three-dimensional Gd-MOF, [Gd(p-XBP4)4(H2O)]·W(CN)8; (1; p-XBP4 = N,N'-p-phenylenedimethylenbis (pyridin-4-one)) has been synthesized by slow-evaporation and its crystal structure was characterized by single-crystal X-ray diffraction (SCXRD) analysis. For each GdIII ion, there are seven coordination sites, which are occupied by six oxygen atoms of six p-XBP4 ligands and one oxygen atom from the water molecule. The [W(CN)8]3- anion exists for charge balance with cationic framework. The GdII ions are interconnected by the p-XBP4 ligand to form the three-dimensional structure. Considering the magnetic property of lanthanide ions, magnetic studies of Gd-MOF were investigated by direct-current (DC) magnetic susceptibilities measurements.

Intercellular Adhesion Molecule-1 Gene Polymorphism (K469E) in Korean Preeclamptic Women

  • Lim, Ji-Hyae;Park, So-Yeon;Kim, Shin-Young;Lee, Moon-Hee;Yang, Jae-Hyug;Kim, Moon-Young;Park, Hyun-Young;Lee, Kwang-Soo;Kim, Young-Ju;Ryu, Hyun-Mee
    • Journal of Genetic Medicine
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    • v.5 no.2
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    • pp.105-110
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    • 2008
  • Purpose: Preecalmpsia is a pregnancy-specific disorder that reflects widespread endothelial dysfunction resulting from increases of adhesion molecule expression. Intercellular adhesion molecule-1 (ICAM-1) is involved in the pathogenetic mechanisms responsible for preeclampsia, and ICAM-1 plasma levels and/or function is genetically influenced. Therefore, we evaluated the distribution of ICAM-1 gene K469E polymorphism in pregnant Korean women with preeclampsia and evaluated the association between this polymorphism and preeclampsia. Methods: The K469E polymorphism was analyzed in peripheral blood samples from 197 preeclamptic pregnancies and 193 normotensive pregnancies by a SNapShot kit and an ABI Prism 3100 Genetic analyzer. Results: Genotypic and allelic frequencies of ICAM-1 gene polymorphism (K469E) did not differ between preeclamptic and normotensive pregnancies. The distributions of the KK, KE, and EE genotypes were 40.6%, 43.7%, and 15.7%, respectively, in preeclamptic pregnancies and 38.9%, 45.1%, and 16.1%, respectively, in normotensive pregnancies. The frequencies of K and E alleles were 0.62 and 0.38, respectively, in preeclamptic pregnancies and 0.61 and 0.39, respectively, in normotensive pregnancies. By multiple logistic regression analysis, there was no increased risk of preeclampsia in subjects with ICAM-1 KE (OR, 1.08; P=0.74) or EE (OR, 1.07; P=0.88) genotypes. Conclusion: This study suggests that the ICAM-1 gene K469E polymorphism does not associate with an increased risk of preeclampsia in pregnant Korean women.

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Theoretical Study of Thiazole Adsorption on the (6,0) zigzag Single-Walled Boron Nitride Nanotube

  • Moradi, Ali Varasteh;Peyghan, Ali Ahmadi;Hashemian, Saeede;Baei, Mohammad T.
    • Bulletin of the Korean Chemical Society
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    • v.33 no.10
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    • pp.3285-3292
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    • 2012
  • The interaction of thiazole drug with (6,0) zigzag single-walled boron nitride nanotube of finite length in gas and solvent phases was studied by means of density functional theory (DFT) calculations. In both phases, the binding energy is negative and presenting characterizes an exothermic process. Also, the binding energy in solvent phase is more than that the gas phase. Binding energy corresponding to adsorption of thiazole on the BNNT model in the gas and solvent phases was calculated to be -0.34 and -0.56 eV, and about 0.04 and 0.06 electrons is transferred from the thiazole to the nanotube in the phases. The significantly changes in binding energies and energy gap values by the thiazole adsorption, shows the high sensitivity of the electronic properties of BNNT towards the adsorption of the thiazole molecule. Frontier molecular orbital theory (FMO) and structural analyses show that the low energy level of LUMO, electron density, and length of the surrounding bonds of adsorbing atoms help to the thiazole adsorption on the nanotube. Decrease in global hardness, energy gap and ionization potential is due to the adsorption of the thiazole, and consequently, in the both phases, stability of the thiazole-attached (6,0) BNNT model is decreased and its reactivity increased. Presence of polar solvent increases the electron donor of the thiazole and the electrophilicity of the complex. This study may provide new insight to the development of functionalized boron nitride nanotubes as drug delivery systems for virtual applications.