Possible involvement of hippocampal immediate-early genes in contextual fear memory deficit induced by cranial irradiation

Son, Y.,Kang, S.,Kim, J.,Lee, S.,Kim, J.C.,Kim, S.H.,Kim, J.S.,Jo, S.K.,Jung, U.,Youn, B.,Shin, T.,Yang, M.,Moon, C. Academic Press, Inc 2016 INC. Vol.133 No.-

Cranial irradiation can trigger adverse effects on brain functions, including cognitive ability. However, the cellular and molecular mechanisms underlying radiation-induced cognitive impairments remain still unknown. Immediate-early genes (IEGs) are implicated in neuronal plasticity and the related functions (i.e., memory formation) in the hippocampus. The present study quantitatively assessed changes in the mRNA and protein levels of the learning-induced IEGs, including Arc, c-fos, and zif268, in the mouse hippocampus after cranial irradiation using quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) and immunohistochemistry, respectively. Mice (male, 8-week-old C57BL/6) received whole-brain irradiation with 0 or 10Gy of gamma-ray and, 2weeks later, contextual fear conditioning (CFC) was used to induce IEGs. In the CFC task, mice evaluated 2weeks after irradiation exhibited significant memory deficits compared with sham (0Gy)-irradiated controls. The levels of mRNA encoding IEGs were significantly upregulated in the hippocampus 10 and 30min after CFC training. The mRNA levels in the irradiated hippocampi were significantly lower than those in the sham-irradiated controls. The IEG protein levels were significantly increased in all hippocampal regions, including the hippocampal dentate gyrus, cornu ammonis (CA)1, and CA3, after CFC training. The CFC-induced upregulation of Arc and c-fos in 10Gy-irradiated hippocampi was significantly lower than that in sham-irradiated controls, although there were no significant differences in the protein levels of the learning-induced zif268 between sham-irradiated and 10Gy-irradiated hippocampi. Thus, cranial irradiation with 10Gy of gamma-ray impairs the induction of hippocampal IEGs (particularly Arc and c-fos) via behavioral contextual fear memory, and this disturbance may be associated with the memory deficits evident in mice after cranial irradiation, possibly through the dysregulation of neuronal plasticity during memory formation.

Bioaccessibility of AhR-active PAHs in sediments contaminated by the Hebei Spirit oil spill: Application of Tenax extraction in effect-directed analysis

Hong, S.,Yim, U.H.,Ha, S.Y.,Shim, W.J.,Jeon, S.,Lee, S.,Kim, C.,Choi, K.,Jung, J.,Giesy, J.P.,Khim, J.S. Pergamon Press 2016 CHEMOSPHERE - Vol.144 No.-

Bioaccessibility of toxic substances in sedimentary residual oil is a crucial factor that needs to be considered for accurate risk assessments posed by oil spills. However, information on oil weathering processes and bioaccessibility of residual oil is often not sufficient and clear. In the present study, bioaccessibility of aryl hydrocarbon receptor (AhR)-active polycyclic aromatic hydrocarbons (PAHs) in coastal sediments near the site of the Hebei Spirit oil spill (Korea, 2007) was assessed by Tenax extraction in effect-directed analysis (EDA). Sediment samples collected 6 years after the oil spill were extracted using Soxhlet or Tenax, and EDA was performed using a battery of H4IIE-luc bioassay and GC/MSD analysis. Concentrations of PAHs and alkyl-PAHs in Soxhlet extracts ranged from 210 to 53,000 μg kg<SUP>-1</SUP> dry mass. However, concentrations of PAHs and alkyl-PAHs in Tenax extracts were approximately 20-fold less compared to those in Soxhlet extracts. In Soxhlet and Tenax extracts, the major AhR-active PAHs were identified as C1-chrysene, C3-chrysene, and C4-phenanthrene. Concentrations of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) equivalents (TEQ<SUB>PAHs</SUB>) explained 31% and 60% of the bioassay-derived TCDD-EQ concentrations in Soxhlet and Tenax extracts, respectively. Overall, bioaccessibility of PAHs and alkyl-PAHs in sedimentary residual oils depended on hydrophobicity (log K<SUB>ow</SUB>) and degree of weathering of crude oil. The results of the present study provide further evidence in support of the biological and ecological recoveries of oil spill sites.

Electrical Properties of SrRuO₃ Thin Films with Varying c-axis Lattice Constant

Young J. Chang,Jin I Kim,C. U. Jung 한국자기학회 2008 Journal of Magnetics Vol.13 No.2

We studied the effect of the variation of the lattice constant on the electrical properties of SrRuO₃thin films. In order to obtain films with different volumes, we varied the substrate temperature and oxygen pressure during the growth of the films on SrTiO₃(001) substrates. The films were grown using a pulsed laser deposition method. The X-ray diffraction patterns of the grown films at low temperature and low oxygen pressure indicated the elongation of the c-axis lattice constant compared to that of the films grown at a higher temperature and higher oxygen pressure. The in-plane strain states are maintained for all of the films, implying the expansion of the unit-cell volume by the oxygen vacancies. The variation of the electrical resistance reflects the temperature dependence of the resistivity of the metal, with a ferromagnetic transition temperature inferred form the cusp of the curve being observed in the range from 110 K to 150 K. As the c-axis lattice constant decreases, the transition temperature linearly increases.

Electrical and Magnetic Properties of <tex> ${\rm Sr}({\rm Ru},{\rm Cr}){\rm O}_{3}$</tex> Thin Films

Ramana, E. Venkata,Park, Hong Woo,Jung, C. U. IEEE 2010 IEEE transactions on magnetics Vol.46 No.6

<P> Cr-doped <TEX>${\rm SrRuO}_{3}$</TEX> (SRCO) thin films were grown on an <TEX>${\rm SrTiO}_{3}$</TEX> (STO) (001) substrate using a pulsed laser deposition method in order to study the effects of the Cr doping. Measurements of the out-of-plane lattice constant and the electrical and magnetic properties indicate that Cr is incorporated into the B-site of the SRO lattice. Magnetic hysteresis measurements reveal a ferromagnetic nature with a saturation magnetization of about 0.75 <TEX>$\mu_{\rm B}/{\rm Ru}$</TEX>. The magnetization measurement of <TEX>${\rm Sr}({\rm Ru}_{0.9}{\rm Cr}_{0.1}){\rm O}_{3}$</TEX> showed a ferromagnetic transition temperature <TEX>$T_{\rm C}=165\ {\rm K}$</TEX>. This <TEX>$T_{\rm C}$</TEX> value is about 13 K higher than that reported for <TEX>${\rm SrRuO}_{3}$</TEX> thin films. The <TEX>$T_{\rm C}$</TEX> enhancement due to Cr doping in <TEX>${\rm SrRuO}_{3}$</TEX> thin film was less than that observed for the bulk sample. Electrical resistivity measurements of the SRCO thin films reveal metallic behavior, with a much larger residual resistivity of <TEX>$\sim 260\ \mu\Omega\ {\rm cm}$</TEX> compared to 26 <TEX>$\mu\Omega$</TEX> cm for <TEX>${\rm SrRuO}_{3}$</TEX> thin films. </P>

돼지 대장에서 분리한 E.coli의 중금속 내성에 관한 연구

조창현,정욱진,이영수,최인실,강희옥,박남규,김명화,변미경,이현숙 경상대학교 환경보전연구소 1993 環境保全硏究所報 Vol.1 No.1

돼지의 대장에서 서식하는 466개의 대장균 균주들을 분리하여, 중금속인 Ag, Cd, Cu, Hg, Ni 및Pb에 대한 저항성을 조사 하였다. 거의 대부분의 균주들이 이들 여섯가지 중금속 모두에 강한 저항성을 보였다. 이것은 우리 주위환경의 중금속 오염 정도가 심각하다는 것을 간접적으로 나타내는 것이다. Ag, Pb 및 Hg를 함유하고 있는 고체 배지에서 균주를 성장시켰을때, colony 색깔이 중금속 자체의 광택과 같은 색깔을 나타내는 점으로 보아, 이들 중금속에 대한 저항기작은 유해한 중금속 이온을 세포내 에서 무해한 금속 형태로 전환시켜 세포내에 축적시키는 기작임을 시사하였다. 그 중 가장 높은 저항성을 나타내는 isolate 385를 Ag와 Pb를 함유한 액체배지에서 각각 배양한 뒤 세포내 Ag와 Pb 축적량을 조사한 결과, 건조세포 무게당 0.72g Ag 및 0.23g Pb를 세포내에 축적하고 있었다. 따라서, 이 균주를 유전자 조작 등의 방법으로 개발 한다면 산업 폐수내에 존재하는 이 중금속들의 제거에 효율적으로 사용할 수 있을 것이라 사료된다. We isolated E.coli from porcine intestines and examined the resistances to various heavy-metals, Ag, Cd, Cu, Hg, Ni, and Pb. The 466 isolates were resistant to the heavy-metals. Among them, 72.1% was survived in 1 mM AgNO₃, 9.3% in 80 mM AgNO₃, 95.9% in 0.6 mM Cd(NO₃)₂, 5.6% in 3 mN Cd(NO₃)₂. 95.9% in Cu(NO₃)₂, 48.5% in 0.2 mM HgCl₂, 3.4% in 0.6 mM HgCl₂, 64.4% in 5 mM NiCl₂ and 67.4% in 10 mM Pb(NO₃)₂. The isolate 385 was most resistant to silver and lead ions and the MICs of the ions were 80 mM and 11 mM, respectively. These resistances were inducible by Ag^+ and Pb^2+ ions. When isolate 385 grew in LB-agar plates containing AgNO₃ or Pb(NO₃)₂, the colony colors were changed from light yellow to deep brown. This change to brown color suggests that the resistances of 385 cells to Ag^+ and Pb^2+ ions were due to the reducing mechanism which converted them into the elementary metals(Ag^0, Pb^0) after the uptake of the ions into the cells. The resistant cells accumulated 0.72gr of Ag^0 and 0.23gr of Pb^0 per cells dry wt.

방향성 연속주조된 Al-Cu합금의 연화처리에 따른 미세조직과 기계적 성질의 변화

제창웅,윤재홍,정동석 國立 昌原大學校 産業技術硏究所 1997 産技硏論文集 Vol.11 No.-

Directionally continuous casted Al-Cu alloys used the components of electronic and electric equipment need to specify the properties of them and optimum drawing condition in order to manufacture a fine wire. Therefore, the present investigation has been carried out for clarifying the changes of macrostructure, microstructure, mechanical properties, and the interrelations of them during annealing heat treatment in order to manufacture a fine wire in directionally continuous casted Al-Cu alloys. Recrystalized grains were not observed at below 200˚C in Al-1%Cu and Al-28%Cu alloys annealed, however recrystalized grains were observed with increasing annealing temperature. Recrystalization was occurred at inclusion/matrix interfaces and also appeared at the inclusions of smaller radius with increasing reduction ratio.

Poster Electrical properties of SrRuO₃ thin films with varying c-axis lattice constant

Young J. Chang,C. U. Jung 한국자기학회 2008 한국자기학회 학술연구발표회 논문개요집 Vol.- No.-

Effect of Rb doping on ferroelectric and piezoelectric properties of Bi_0.5Na_0.5TiO₃-BaTiO₃ thin films

Acharya, S.K.,Ahn, B.G.,Jung, C.U.,Koh, J.H.,Choi, I.H.,Lee, S.K. Elsevier Sequoia 2014 JOURNAL OF ALLOYS AND COMPOUNDS Vol.603 No.-

Rb doped 0.94Bi<SUB>0.5</SUB>Na<SUB>0.5</SUB>TiO<SUB>3</SUB>-0.06BaTiO<SUB>3</SUB> (BNT-BT-Rb<SUB>x</SUB>) thin films with xmol% Rb (x=0, 2.5, 5, 7.5, 10) were deposited on Pt/Ti/SiO<SUB>2</SUB>/Si substrate by metal-organic solution deposition method. Experiments were conducted to investigate the effect of Rb doping on phase formation, microstructure, leakage current, and the resulting ferroelectric and piezoelectric property. It was found that substantial enhancement in structural, morphological and electrical properties can be achieved by Rb doping of BNT-BT thin films. Optimal electrical properties were obtained for 5mol% Rb doped BNT-BT thin films, with a dielectric constant, remnant polarization, and effective piezoelectric constant of ~681, ~28.9μC/cm<SUP>2</SUP> and ~86pm/V, respectively. It was suggested that the enhanced electrical properties in the case of 5mol% Rb BNT-BT thin films can be attributed to domain wall movement induced by A-site substitutions, large grain size, and lattice distortion.

Enhanced delivery of liposomes to lung tumor through targeting interleukin-4 receptor on both tumor cells and tumor endothelial cells

Chi, L.,Na, M.H.,Jung, H.K.,Vadevoo, S.M.P.,Kim, C.W.,Padmanaban, G.,Park, T.I.,Park, J.Y.,Hwang, I.,Park, K.U.,Liang, F.,Lu, M.,Park, J.,Kim, I.S.,Lee, B.H. Elsevier Science Publishers 2015 Journal of controlled release Vol.209 No.-

A growing body of evidence suggests that pathological lesions express tissue-specific molecular targets or biomarkers within the tissue. Interleukin-4 receptor (IL-4R) is overexpressed in many types of cancer cells, including lung cancer. Here we investigated the properties of IL-4R-binding peptide-1 (IL4RPep-1), a CRKRLDRNC peptide, and its ability to target the delivery of liposomes to lung tumor. IL4RPep-1 preferentially bound to H226 lung tumor cells which express higher levers of IL-4R compared to H460 lung tumor cells which express less IL-4R. Mutational analysis revealed that C1, R2, and R4 residues of IL4RPep-1 were the key binding determinants. IL4RPep-1-labeled liposomes containing doxorubicin were more efficiently internalized in H226 cells and effectively delivered doxorubicin into the cells compared to unlabeled liposomes. In vivo fluorescence imaging of nude mice subcutaneously xenotransplanted with H226 tumor cells indicated that IL4RPep-1-labeled liposomes accumulate more efficiently in the tumor and inhibit tumor growth more effectively compared to unlabeled liposomes. Interestingly, expression of IL-4R was high in vascular endothelial cells of tumor, while little was detected in vascular endothelial cells of control organs including the liver. IL-4R expression in cultured human vascular endothelial cells was also up-regulated when activated by a pro-inflammatory cytokine tumor necrosis factor-α. Moreover, the up-regulation of IL-4R expression was observed in primary human lung cancer tissues. These results indicate that IL-4R-targeting nanocarriers may be a useful strategy to enhance drug delivery through the recognition of IL-4R in both tumor cells and tumor endothelial cells.

Structural and Magnetic Properties of LaFeO₃-BaTiO₃ Solid Solutions

E. Venkata Ramana,O-Ung Kwon,Jin I Kim,C. U. Jung 한국자기학회 2009 Journal of Magnetics Vol.14 No.3

Polycrystalline samples of LaFeO3-BaTiO₃ were synthesized to examine the structural and magnetic behavior. X-ray diffraction confirmed that the ceramics had tetragonal symmetry with less tetragonal strain (c/a) than BaTiO₃. The magnetic hysteresis measured at room temperature suggested that the magnetic nature deviates from that of the parent LaFeO₃, which has antiferromagentic with a G-type spin structure. Improved magnetic behavior of the solid solution compound might be due to the increase in the canting angle of the spin. The presence of oxygen vacancies and fluctuating Fe valence, arising from the substitution of Ba<SUP>2+</SUP> and Ti<SUP>4+</SUP> at the A- and B-sites of the lattice, might contribute to bulk magnetization. The temperature dependent magnetization indicated that magnetization was higher at low temperatures and showed a decreasing trend with increasing temperature to room temperature. The magnetic transition temperature of these samples was 665 K and 743 K for the mixed system and LaFeO₃, respectively.