[ $^1H$ ] Nuclear Magnetic Resonance Study of Ferroelectric $(NH_4)_3H(SO_4)_2$

Choi, S.H.,Han, K.S.,Kwon, S.K.,Nam, S.K.,Choi, H.H.,Lee, Moo-Hee,Lim, Ae-Ran Korean Magnetic Resonance Society 2007 Journal of the Korean Magnetic Resonance Society Vol.11 No.2

[ $^1H$ ] nuclear magnetic resonance (NMR) experiments have been performed at 30 - 300 K and 7 T to investigate dynamics of hydrogen bond network in the single crystal $(NH_4)_3H(SO_4)_2$. The two proton sites, ammonium proton and hydrogen-bond proton, are identified from the $^1H$ NMR MAS spectrum at 340 K. As temperature decreases, the $^1H$ NMR spectrum shifts to the higher frequency side with a larger linewidth. The spectrum at 65 K shows a distinctive change in line shape toward the ferroelectric transition at 63 K. The measured values of $T_1$ for ammonium and hydrogen-bond protons are similar in the whole range of temperature. $T_1$ of $^1H$ NMR shows a gradual decrease down to 120 K and starts to steeply increase below 100 K. Then $T_1$ shows abrupt decrease below 70 K with a sharp minimum at 63 K, where the ferroelectric transition occurs. This temperature dependence of spectrum and $T_1$ clearly prove that the large change in the dynamics of hydrogen bond network is associated with the ferroelectric phase transition at 63 K.

K - 통로개방제가 배양심근세포와 생쥐 체내의 Thallium - 201 역동학에 미치는 영향

이규보(Kyu Bo Lee),이재태(Jae Tae Lee),안병철(Byeong Cheol Ahn),김은지(Eun Ji Kim),손상균(Kang Kyun Sohn),하정희(Jeoung Hee Ha),김천기(Chun K . Kim) 대한핵의학회 1996 핵의학 분자영상 Vol.30 No.4

N/A Background: Potassium channel opener (K-opener) opens ATP-sensitive K+-channel located at membrane and induces potassium efflux from cytosol, resulting in intracellular hyperpolarization. Newly synthesized K-opener is currently examined for pharmacologic potency by means of rubidium release test from smooth muscle strip pre-incubated with Rb-86. Since in-vive behavior of thallium is similar to that of rubidium, we hypothesized that K-opener can alter T1-201 kinetics in vivo. Purpose: This study was prepared to investigate the effects of pinacidil (one of potent K-openers) on the T1-201 uptake and clearance in cultured myocyte, and in-vivo biodi- stribution in mice. Methods: Spontaneous contracting myocytes were prepared to imitate in-vivo condition from 20 hearts of 3-5 days old Sprague-Dawley rat and cultured for 3-5 days before use (5×105 cells/ml). Pinacidil was dissolved in 10% DMSO solution at a final concentration of 100nM or 10uM and was co-incubated with T1-201 in HBSS buffer for 20-min to evaluate its effect on cellular T1-uptake, or challenged to cell preparation pre-incubated with T1-201 for washout study. Two, 40 or 100μg of pinacidil was injected intravenously into ICR mice at 10 min after 5μCi T1-201 injection, and organ uptake and whole body retention rate were measured at different time points. Results: Co-incubation of pinacidil with T1-201 resulted in a decrease in T1-201 uptake into cultured myocyte by 1.6 to 2.5 times, depending on pinacidil concentration and activity of T1-201 used. Pinacidil enhanced T1-201 washout by 1.6-3.1 times from myocyte preparations pre-incubated with T1-201. Pinacidil treatment appears to be resulted in mild decreases in blood and liver activity in normal mice, in contrast, renal and cardiac uptake were mildly decreased in a dose dependent manner. Whole body retention ratios of T1-201 were lower at 24 hour after injection with 100μg of pinacidil than control. Conclusion: These results suggest that treatment with K-opener may affect the interpretation of T1-201myocardial images, due to decreasing thallium accumulation and enhancing washout from myocardium.

Evaluation of Cytotoxicity, Antimicrobial and Antioxidant Enzyme Activity of Diploid and Tetraploid Platycodon grandiflorum

Hee-Ock Boo,Young-Sun Kim,Hag-Hyun Kim,Soo-Jeong Kwon,Sun-Hee Woo 한국작물학회 2015 Korean journal of crop science Vol.60 No.2

This experiment was conducted to obtain the have higher contents of pharmaceutical constituents as well as higher yield from colchicine induced diploid and tetraploid extracts of Platycodon grandiflorum. In order to determine the biological activity, this study was focused to evaluate the cytotoxicity, antimicrobial on the bronthus disease bacteria, antioxidant enzyme activity of diploid and tetraploid extracts in P. grandiflorum. The activities of antioxidant enzyme according to different solvent extracts were measured as superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and ascorbate peroxidase (APX). The cytotoxicity of methanol extracts of P. grandiflorum showed significant differences between tetraploid and diploid. That is, the cytotoxic effect against human cancer cell was higher in tetraploid than in diploid. At all extracts concentration, tetraploid samples showed high toxicity and the IC50 (concentration causing 50% cell death) value showed the highest on HCT-116 cell (105.91 μg/mL), and exhibited significant activity against the Hep 3B cell (140.67 μg/mL), SNU-1066 cell (154.01 μg/mL), Hela cell (158.37 μg/mL), SNU-601 cell (182.67 μg/mL), Calu-6 cell (190.42 μg/mL), MCF-7 cell (510.19 μg/mL). Antimicrobial activities of diploid P. grandiflorum were relatively low compared to tetraploid P. grandiflorum on most of the bacterial strains. In tetraploid P. grandiflorum, K. pneumoniae showed the clear zone formation (18~19 mm) of growth inhibition, followed by the clear zone formation of 13~15 mm on C. diphtheria and S. pyogenes. The antimicrobial activities in diploid P. grandiflorum were the highest on K. pneumonia (14~15 mm), and showed the clear zone formation of 11~12 mm on C. diphtheria and 12~13 mm on S. pyogenes. The antimicrobial activity is thought to look different depending on the bacterial strains and the polyploidy of P. grandiflorum. The root extract of P. grandiflorum had the highest (97.2%) SOD enzyme activity in ethyl acetate partition layer of tetraploid while water partition layer of diploid showed the lowest (48.6%) SOD enzyme activity. The activity of CAT showed higher values in the root of tetraploid than in the diploid of P. grandiflorum in all partition layers except butyl alcohol. The activities of APX and POD showed higher values in the root of tetraploid than in the diploid of P. grandiflorum in all fraction solvents except water layer. These results indicate that the tetraploid P. grandiflorum can be used as a source for developing cytotoxic agent and antimicrobials which can act against bronchus diseases bacterial strains.

Efficient long-term amplification of hepatitis B virus isolates after infection of slow proliferating HepG2-NTCP cells

Kö,nig, Alexander,Yang, Jaewon,Jo, Eunji,Park, Kyu Ho Paul,Kim, Hyun,Than, Thoa Thi,Song, Xiyong,Qi, Xiaoxuan,Dai, Xinghong,Park, Soonju,Shum, David,Ryu, Wang-Shick,Kim, Jung-Hee,Yoon, Seung Kew,P Elsevier 2019 Journal of hepatology Vol.71 No.2

<P><B>Background & Aims</B></P> <P>As hepatitis B virus (HBV) spreads through the infected liver it is simultaneously secreted into the blood. HBV-susceptible <I>in vitro</I> infection models do not efficiently amplify viral progeny or support cell-to-cell spread. We sought to establish a cell culture system for the amplification of infectious HBV from clinical specimens.</P> <P><B>Methods</B></P> <P>An HBV-susceptible sodium-taurocholate cotransporting polypeptide-overexpressing HepG2 cell clone (HepG2-NTCPsec+) producing high titers of infectious progeny was selected. Secreted HBV progeny were characterized by native gel electrophoresis and electron microscopy. Comparative RNA-seq transcriptomics was performed to quantify the expression of host proviral and restriction factors. Viral spread routes were evaluated using HBV entry- or replication inhibitors, visualization of viral cell-to-cell spread in reporter cells, and nearest neighbor infection determination. Amplification kinetics of HBV genotypes B-D were analyzed.</P> <P><B>Results</B></P> <P>Infected HepG2-NTCPsec+ secreted high levels of large HBV surface protein-enveloped infectious HBV progeny with typical appearance under electron microscopy. RNA-seq transcriptomics revealed that HBV does not induce significant gene expression changes in HepG2-NTCPsec+, however, transcription factors favoring HBV amplification were more strongly expressed than in less permissive HepG2-NTCPsec−. Upon inoculation with HBV-containing patient sera, rates of infected cells increased from 10% initially to 70% by viral spread to adjacent cells, and viral progeny and antigens were efficiently secreted. HepG2-NTCPsec+ supported up to 1,300-fold net amplification of HBV genomes depending on the source of virus. Viral spread and amplification were abolished by entry and replication inhibitors; viral rebound was observed after inhibitor discontinuation.</P> <P><B>Conclusions</B></P> <P>The novel HepG2-NTCPsec+ cells efficiently support the complete HBV life cycle, long-term viral spread and amplification of HBV derived from patients or cell culture, resembling relevant features of HBV-infected patients.</P> <P><B>Lay summary</B></P> <P>Currently available laboratory systems are unable to reproduce the dynamics of hepatitis B virus (HBV) spread through the infected liver and release into the blood. We developed a slowly dividing liver-derived cell line which multiplies infectious viral particles upon inoculation with patient- or cell culture-derived HBV. This new infection model can improve therapy by measuring, in advance, the sensitivity of a patient’s HBV strain to specific antiviral drugs.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Cell culture system that mimicks complete HBV life cycle from entry to egress. </LI> <LI> Efficient <I>in vitro</I> infection with crude HBV patient sera. </LI> <LI> Up to 50- and 1,300-fold net amplification of patient- and cell culture-derived input HBV in the supernatant. </LI> <LI> Polyethylene glycol-independent HBV spread to adjacent cells, forming infected cell clusters. </LI> <LI> Evaluation of patient- and cell culture-derived HBV amplification w/wo antivirals over 8 weeks. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

공공정보의 이용활성화 현황분석과 정책제안

이회광(Hee-K때ng Lee),양제민(Jemin Yang),박재천(Jaechon Park) 한국통신학회 2006 한국통신학회 학술대회논문집 Vol.2006 No.11

A Study on Gas Adsorption on Microporous Carbons

( Hak Hee Kim ),( Joachim K. Floess ) 한국공업화학회 1993 한국공업화학회 연구논문 초록집 Vol.1993 No.0

A study of physical adsorption of gases by microporous carbons was carried out. A volumetric adsorption apparatus, which was designed to measure the pressure, temperature, and gas sample volume before and after contact with the adsorbent, was used in order to collect adsorption data. The analysis of adsorption data gave quantitative information on the specific surface area, pore volume, and micropore size using various adsorption models such as the Brunauer-Emmett-Teller, Dubinin- Radushkevich, Langmuir, and Volmer models, and also gave information on the thermodynamic data such as the isosteric heat of adsorption, differential energy of adsorption, and differential entropy of adsorption in order to characterize the degree of the surface heterogeneity for both microporous carbons. The isosteric heat of adsorption of nitrogen on Spherocarb was calculated to be 3.39 kcal/mol, and that of nitrogen on Sucrose Char was calculated to be 5.08 kcal/mol from the van't Hoff plots of the Henry's law constants at temperatures from 77 K to 184 K. These chars have a higher adsorption energy than graphite. Based on changes in the isosteric heat of adsorption with coverage, adsorption sites on the Spherocarb and Sucrose Char are energetically inhomogeneous, The Volmer model which is based upon the mobile adsorption was compared with the Langmuir model which is based upon the localized adsorption. At 77 K, the fractional coverage of adsorption sites of the Langmuir isotherm on both carbons with same adsorption energy is always larger than that of the Volmer isotherm, but at 113 K that of the Langmuir isotherm is smaller than that of the Volmer isotherm in the low pressure regime, while that of the Langmuir isotherm is larger than that of the Volmer isotherm in the high pressure regime. It was observed that for large d/rG there exist two minima in the potential energy curves and these curves become wide and shallow. Whereas, for small d/r_o there exists only one minimum in thepotential energy curves and these curves become narrow and deep. The potential energy profile for Sucrose Char is deeper and wider than that for Spherocarb when the 10:4 potential function was applied to slit shaped pores between single layer planes and the 9:3 potential function to slit shaped pores between slabs.

Block of hERG K⁺ channel and prolongation of action potential duration by fluphenazine at submicromolar concentration

Hong, H.K.,Hoon Lee, B.,Park, M.H.,Ho Lee, S.,Chu, D.,Jin Kim, W.,Choe, H.,Hee Choi, B.,Jo, S.H. North-Holland ; Elsevier Science Ltd 2013 european journal of pharmacology Vol.702 No.1

Fluphenazine is a potent antipsychotic drug that can increase action potential duration and induce QT prolongation in several animal models and in humans. As the block of cardiac human ether-a-go-go-related gene (hERG) channels is one of the leading causes of acquired long QT syndrome, we investigated the acute effects of fluphenazine on hERG channels to determine the electrophysiological basis for its proarrhythmic potential. Fluphenazine at concentrations of 0.1-1.0μM increased the action potential duration at 90% of repolarization (APD<SUB>90</SUB>) and action potential duration at 50% of repolarization (APD<SUB>50</SUB>) in 5min when action potentials were elicited under current-clamp conditions in guinea pig ventricular myocytes. We examined the effects of fluphenazine on hERG channels expressed in Xenopus oocytes and HEK293 cells using two-microelectrode voltage-clamp and patch-clamp techniques. The IC<SUB>50</SUB> for the fluphenazine-induced block of hERG currents in HEK293 cells at 36<SUP>o</SUP>C was 0.102μM at +20mV. Fluphenazine-induced a concentration-dependent decrease of the current amplitude at the end of the voltage steps and hERG tail currents. The fluphenazine-dependent hERG block in Xenopus oocytes increased progressively relative to the degree of depolarization. Fluphenazine affected the channels in the activated and inactivated states but not in the closed states, and the S6 domain mutation from tyrosine to alanine at amino acid 652 (Y652A) attenuated the hERG current block. These results suggest that the antipsychotic drug fluphenazine is a potent blocker of hERG channels, providing a molecular mechanism for the drug-induced arrhythmogenic side effects.

Hexacoordinated Sn(IV) porphyrin-based square-grid frameworks exhibiting selective uptake of CO2 over N2

Shee Nirmal K.,Lee Chang‐Ju,Kim Hee‐Joon 대한화학회 2022 Bulletin of the Korean Chemical Society Vol.43 No.1

We prepared porphyrin metal–organic frameworks with hexacoordinated Sn(IV) porphyrin trans-SnX2(TPyP), where X = Cl, OH; TPyP = 5,10,15,20-tetra (4-pyridyl)porphyrinato dianion, and Cu(II) acetate, namely {[SnCl2(TPyP)][Cu (OAc)2]4}4DMF4H2O (1) and {[Sn(OH)2(TPyP)][Cu(OAc)2]4}xSolv (2). X-ray crystallographic analysis revealed that both materials consisted of the same square-grid two-dimensional (2D) sheet. The small difference in the trans-axial ligand coordinated to the Sn(IV) center creates distinctively different packing structures. As a consequence of the Cl π and Cl Cl interactions between the adjacent layers in 1, squares of stacked 2D layers are well aligned, giving a single type of ordered porous channel. In contrast, adjacent 2D layers in 2 are stacked along the c-axis with an ABAB sequence with an average delamination of 7.05 Å. The coordination network structures of both materials provide large free voids without interpenetration. Gas sorption studies showed that both porous materials exhibit 10 times higher CO2 adsorption than N2 at 273 K.

Aerosol delivery of urocanic acid-modified chitosan/programmed cell death 4 complex regulated apoptosis, cell cycle, and angiogenesis in lungs of K-ras null mice.

Jin, Hua,Kim, Tae Hee,Hwang, Soon-Kyung,Chang, Seung-Hee,Kim, Hyun Woo,Anderson, Hanjo K,Lee, Han-Woong,Lee, Kee-Ho,Colburn, Nancy H,Yang, Hsin-Sheng,Cho, Myung-Haing,Cho, Chong Su American Association for Cancer Research, Inc 2006 Molecular cancer therapeutics Vol.5 No.4

<P>The low efficiency of conventional therapies in achieving long-term survival of patients with lung cancer calls for development of novel treatment options. Although several genes have been investigated for their antitumor activities through gene delivery, problems surrounding the methods used, such as efficiency, specificity, and toxicity, hinder application of such therapies in clinical settings. Aerosol gene delivery as nonviral and noninvasive method for gene therapy may provide an alternative for a safer and more effective treatment for lung cancer. In this study, imidazole ring-containing urocanic acid-modified chitosan (UAC) designed in previous study was used as a gene carrier. The efficiency of UAC carrier in lungs was confirmed, and the potential effects of the programmed cell death protein 4 (PDCD4) tumor suppressor gene on three major pathways (apoptosis, cell cycle, and angiogenesis) were evaluated. Aerosol containing UAC/PDCD4 complexes was delivered into K-ras null lung cancer model mice through the nose-only inhalation system developed by our group. Delivered UAC/PDCD4 complex facilitated apoptosis, inhibited pathways important for cell proliferation, and efficiently suppressed pathways important for tumor angiogenesis. In summary, results obtained by Western blot analysis, immunohistochemistry, and terminal deoxynucleotidyl transferase-mediated nick end labeling assay suggest that our aerosol gene delivery technique is compatible with in vivo gene delivery and can be applied as a noninvasive gene therapy.</P>

Brillouin Light Scattering Study of the Magnetic Anisotropy in bcc-Fe(100) Ultrathin Films Grown on GaAs(100) Surfaces With Different Reconstructions

Seung-Seok Ha,Nam-Hee Kim,Chun-Yeol You,Sukmock Lee,Ohta, K.,Maruyama, T.,Konishi, K.,Nozaki, T.,Suzuki, Y.,Van Roy, W. IEEE 2009 IEEE transactions on magnetics Vol.45 No.6

<P>We investigated the magnetic anisotropy of ultrathin bcc-Fe (001) films with a fcc-Au(001) cover layer, grown onto GaAs (001) (4 times 1) and (2 times 6)/(3 times 6) reconstructed surfaces. The magneto-optical Kerr effect hysteresis loops revealed existence of a strong in-plane uniaxial magnetic anisotropy in the Fe films grown on both the surfaces. Details of the in-plane uniaxial anisotropy (K<SUB>U</SUB>), cubic anisotropy (K<SUB>C</SUB>), and effective demagnetization field (4piM<SUB>eff</SUB>) were studied by Brillouin light scattering method. We observed a stronger reduction of K<SUB>U</SUB>, K<SUB>C</SUB>, and 4piM<SUB>eff</SUB> in thinner Fe layers (below 1.3 nm) grown on both the surfaces. In the case of Fe films grown on GaAs (4 times 1) surface, anisotropies observed were smaller than that for the (2 times 6)/(3 times 6) surface. This reflects the role of surface structure in determining the magnetic anisotropies.</P>