Effect of thermal annealing on low-energy C-ion irradiated MgB₂ thin films

Jung, Soon-Gil,Son, Seung-Ku,Pham, Duong,Lim, W.C.,Song, J.,Kang, W.N.,Park, T. The Korea Institute of Applied Superconductivity a 2019 한국초전도저온공학회논문지 Vol.21 No.3

We investigate the effect of thermal annealing on $MgB_2$ thin films with thicknesses of 400 and 800 nm, irradiated by 350 keV C-ions with a dose of $1{\times}10^{15}atoms/cm^2$. Irradiation by low-energy C-ions produces atomic lattice displacement in $MgB_2$ thin films, improving magnetic field performance of critical current density ($J_c$) while reducing the superconducting transition temperature ($T_c$). Interestingly, the lattice displacement and the $T_c$ are gradually restored to the original values with increasing thermal annealing temperature. In addition, the magnetic field dependence of $J_c$ also returns to that of the pristine state together with the restoration of $T_c$. Because $J_c$(H) is sensitive to the type and density of the disorder, i.e. vortex pinning, the recovery of $J_c$(H) in irradiated $MgB_2$ thin films by thermal annealing indicates that low-energy C-ion irradiation on $MgB_2$ thin films primarily causes lattice displacement. These results provide new insights into the application of low-energy irradiation in strategically engineering critical properties of superconductors.

OBSERVATIONS OF THE $J=1{\rightarrow}0$ TRANSITIONS OF $^{12}CO,\;^{13}CO\;and\;C^{18}O$ TOWARD OMC-1

SONG H. J.,CHUN M. S.,MINH Y. C. The Korean Astronomical Society 1993 Journal of The Korean Astronomical Society Vol.26 No.1

Using the Daeduk Radio Telescope, we have observed $J=1\rightarrow0$ transitions of 1$^{12}CO,\;^{13}CO\;and\;C^{18}O$ toward OMC-l. The column densities of $1\~5\times10^{17}\;cm^{-2}\;and\;1\~3\times10^{16}\;cm^{-2}$ have been derived, for $^{13}CO$ and $C^{18}O$, respectively, in the $11'\times11'$ region centered at Orion - KL. The double isotope ratio $[^{13}CO]/[C^{18}O]$ was found to be larger than the cosmic abundance ratio by factors of $2\~10$ which may result from the chemical fractionation effect.

Enhanced adipogenic differentiation and reduced collagen synthesis induced by human periodontal ligament stem cells might underlie the negative effect of recombinant human bone morphogenetic protein‐2 on periodontal regeneration

Song, D‐,S.,Park, J‐,C.,Jung, I‐,H.,Choi, S‐,H.,Cho, K‐,S.,Kim, C‐,K.,Kim, C‐,S. Blackwell Publishing Ltd 2011 Journal of periodontal research Vol.46 No.2

<P> <I>Song D‐S, Park J‐C, Jung I‐H, Choi S‐H, Cho K‐S, Kim C‐K, Kim C‐S. Enhanced adipogenic differentiation and reduced collagen synthesis induced by human periodontal ligament stem cells might underlie the negative effect of recombinant human bone morphogenetic protein‐2 on periodontal regeneration. J Periodont Res 2011; 46: 193–203. © 2010 John Wiley & Sons A/S</I> </P><P><B>Background and Objective: </B> Recombinant human bone morphogenetic protein‐2 (rhBMP‐2) is a potent inducer for the regeneration of mineralized tissue, but has a limited effect on the regeneration of cementum and periodontal ligament (PDL). The aim of the present study was to determine the effects of rhBMP‐2 on the <I>in vitro</I> and <I>in vivo</I> biologic activity of well‐characterized human PDL stem cells (hPDLSCs) and to elucidate the underlying mechanism of minimal periodontal regeneration by rhBMP‐2.</P><P><B>Material and Methods: </B> hPDLSCs were isolated and cultured, and then transplanted into an ectopic subcutaneous mouse model using a carrier treated either with or without rhBMP‐2. Comprehensive histologic, histometric and immunohistochemical analyses were performed after an 8‐wk healing period. The effects of rhBMP‐2 on the adipogenic and osteogenic/cementogenic differentiation of hPDLSCs were also evaluated. The effect of rhBMP‐2 on both soluble and insoluble collagen synthesis was analyzed, and the expression of mRNA and protein for collagen types I, II, III and V was assessed.</P><P><B>Results: </B> In the present study, rhBMP‐2 promoted both adipogenic and osteogenic/cementogenic differentiation of hPDLSCs <I>in vitro</I>, and the <I>in vivo</I> potential of hPDLSCs to form mineralized cementum and organized PDL tissue was down‐regulated following treatment with rhBMP‐2. Collagen synthesis, which plays a crucial role in the regeneration of cementum and the periodontal attachment, was significantly reduced, with associated modification of the relevant mRNA and protein expression profiles.</P><P><B>Conclusion: </B> In summary, the findings of the present study suggest that enhanced adipogenic differentiation and inhibition of collagen synthesis by hPDLSCs appear to be partly responsible for the minimal effect of rhBMP‐2 on cementum and PDL tissue regeneration by hPDLSCs.</P>

Real-time Tumor Oxygenation Changes After Single High-dose Radiation Therapy in Orthotopic and Subcutaneous Lung Cancer in Mice: Clinical Implication for Stereotactic Ablative Radiation Therapy Schedule Optimization

Song, C.,Hong, B.J.,Bok, S.,Lee, C.J.,Kim, Y.E.,Jeon, S.R.,Wu, H.G.,Lee, Y.S.,Cheon, G.J.,Paeng, J.C.,Carlson, D.J.,Kim, H.J.,Ahn, G.O. Pergamon Press 2016 International journal of radiation oncology, biolo Vol.95 No.3

<P>Purpose: To investigate the serial changes of tumor hypoxia in response to single high-dose irradiation by various clinical and preclinical methods to propose an optimal fractionation schedule for stereotactic ablative radiation therapy. Methods and Materials: Syngeneic Lewis lung carcinomas were grown either orthotopically or subcutaneously in C57BL/6 mice and irradiated with a single dose of 15 Gy to mimic stereotactic ablative radiation therapy used in the clinic. Serial [F-18]-misonidazole (F-MISO) positron emission tomography (PET) imaging, pimonidazole fluorescence-activated cell sorting analyses, hypoxia-responsive element-driven bioluminescence, and Hoechst 33342 perfusion were performed before irradiation (day -1), at 6 hours (day 0), and 2 (day 2) and 6 (day 6) days after irradiation for both subcutaneous and orthotopic lung tumors. For F-MISO, the tumor/brain ratio was analyzed. Results: Hypoxic signals were too low to quantitate for orthotopic tumors using F-MISO PET or hypoxia-responsive element-driven bioluminescence imaging. In subcutaneous tumors, the maximum tumor/brain ratio was 2.87 +/- 0.483 at day -1, 1.67 +/- 0.116 at day 0, 2.92 +/- 0.334 at day 2, and 2.13 +/- 0.385 at day 6, indicating that tumor hypoxia was decreased immediately after irradiation and had returned to the pretreatment levels at day 2, followed by a slight decrease by day 6 after radiation. Pimonidazole analysis also revealed similar patterns. Using Hoechst 33342 vascular perfusion dye, CD31, and cleaved caspase 3 coimmunostaining, we found a rapid and transient vascular collapse, which might have resulted in poor intratumor perfusion of F-MISO PET tracer or pimonidazole delivered at day 0, leading to decreased hypoxic signals at day 0 by PET or pimonidazole analyses. Conclusions: We found tumor hypoxia levels decreased immediately after delivery of a single dose of 15 Gy and had returned to the pretreatment levels 2 days after irradiation and had decreased slightly by day 6. Our results indicate that single high-dose irradiation can produce a rapid, but reversible, vascular collapse in tumors. (C) 2016 Elsevier Inc. All rights reserved.</P>

Quantifying herbicide dose-response and resistance in <i>Echinochloa</i> spp. by measuring root length in growth pouches

Zhang, C. J.,Lim, S. H.,Kim, J. W.,Song, J. S.,Yook, M. J.,Nah, G.,Valverde, B. E.,Kim, D. S. Canadian Science Publishing 2015 Canadian journal of plant science. Revue canadienn Vol.95 No.6

<P> Zhang, C. J., Lim, S. H., Kim, J. W., Song, J. S., Yook, M. J., Nah, G., Valverde, N. E. and Kim, D. S. 2015. Quantifying herbicide dose-response and resistance in Echinochloa spp. by measuring root length in growth pouches. Can. J. Plant Sci. 95: 1181-1192. The aim of the presented study was to develop a bioassay for rapid diagnosis of herbicide dose-response and resistance in Echinochloa. Pre-germinated seeds of Echinochloa spp. were incubated in growth pouches (18 cm×16.5 cm) containing herbicide solutions in a range of concentrations. Shoot and root lengths were measured after 6 d of incubation. Dose-responses estimated by measuring root lengths in the growth pouches were well-described by the log-logistic dose-response model and similar to those estimated by a whole-plant assay. Accurate dose-response curves were successfully generated for several herbicides with different modes of action, suggesting that the growth pouch method can be used for herbicide bioassays. The suitability of the growth pouch method for rapid diagnosis of acetyl coenzyme-A carboxylase (ACCase) and acetolactate synthase (ALS) inhibitor resistance in Echinochloa spp. was also tested. For cyhalofop-butyl, resistant and susceptible biotypes were discriminated at 180-300 mg a.i. L<SUP>−1</SUP> and 80-120 mg a.i. L<SUP>−1</SUP> for barnyardgrass (E. crus-galli) and late watergrass (E. oryzicola), respectively. For penoxsulam, the discriminatory dosage was 350-500 mg a.i. L<SUP>−1</SUP> for barnyardgrass and 650-1000 mg a.i. L<SUP>−1</SUP> for late watergrass. The method was further used to identify late watergrass biotypes resistant and susceptible to two other ALS inhibitors, azimsulfuron and bispyribac-sodium. Our results show that the growth pouch method can be reliably used in herbicide dose-response studies and to diagnose herbicide resistance in Echinochloa spp., with significant time and cost savings compared with conventional whole-plant assays. </P>

Synthesis and its characterization of pitch from pyrolyzed fuel oil (PFO)

Kim, J.G.,Kim, J.H.,Song, B.J.,Lee, C.W.,Im, J.S. Korean Society of Industrial and Engineering Chemi 2016 Journal of industrial and engineering chemistry Vol.36 No.-

<P>Pitch synthesis from pyrolyzed fuel oil (PFO) was conducted to understand the empirical synthesis tendency as a function of reaction temperature. Additionally, the chemical and physical characteristics of PFO and produced pitch are identified using X-ray diffraction analysis, thermogravimetric analysis, softening point analysis, and matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) analysis. The produced pitch exhibited an enhanced stacking height (L-C) value and C/H ratio, which is related to the formation of graphitic structure, according to the increased reaction temperature. The carbon residue yield obtained at 900 degrees C showed a gradually increased value of up to 42.58% in the sample synthesized at the temperature of 410 degrees C, depending on the increased reaction temperature. The molecular weight distribution of the produced pitches exhibited noticeable variation during the thermal reaction via MALDI-TOF analysis. The variation of the molecular weight fraction is assumed based on the pitch synthesis mechanism, e.g., polymerization, condensation and cracking reaction. (C) 2016 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.</P>

전주 근교 농장의 자돈에서 면역형광항체법을 이용한 돼지콜레라 혈청 중화항체가 조사

허창열,김영진,노수일,김진구,송희종,김종면 全北大學校 附設 畜産開發硏究所 1991 畜産開發硏究報告 Vol.4 No.-

In order to evaluate the effect of vaccinantion for hog-cholera virus, sera were collected from each 20 piglet out of 26-32 days old before vaccination, and then from the 14th and 28th day post-vaccination(PV) with LOM live virus vaccine at the J and C swine ranches in the suburbs of Chonju. Monoclonal antibody(MAb) against ALD strain of hog cholera virus(HCV) and goal antimouse FITC-conjugates were employed in indirect immunofluorescence(IF) test for the titration of HCV and neuralization IF test for serum neutralization(SN)-Ab-titers against HCV. SN-Ab-titers(M±S.D.) were <2±0 in all piglets before vaccination at the both swine ranches. Whereas SN-Ab-titers of the J and C swine ranches were 111.2±115.08 and 144±121.7 at the 14th day PV and were 361.6±279.6 and 723.2±966.2 at the 28th day PV, respectively. Compared with Duncan's test, SN-Ab-titers were not significantl difference between the H and C swine ranches of the 14th day PV, but were significantly difference at the 28th day PV (P<0.0009). Therefore, SN-Ab-titers were significantly difference between the 14th and 28th day at the J or C ranches, respectively(P<0.0007, P<0.0114). Excepting SN-Ab-titer was1:16 in one piglet of the 14th day PV at the J swine ranch, defensible levels of SN-Ab-titers could be detected in all piglets PV of the both swine ranches. It is suggested that varied dffect of vaccination against HCV may be depended by feed and mangement, enviroment, sanitary conditions, breed and pedigree or vaccination program, etc.

Application of a wet oxidation method for the quantification of ³H and ¹⁴C in low-level radwastes

Ahn, H.J.,Song, B.C.,Sohn, S.C.,Lee, M.H.,Song, K.,Jee, K.Y. Pergamon Press ; Elsevier Science Ltd 2013 Applied radiation and isotopes Vol.81 No.-

Wet oxidation methods are utilized to separate and quantify <SUP>3</SUP>H and <SUP>14</SUP>C radionuclides in inorganic and organic radwastes generated at nuclear facilities. Because <SUP>3</SUP>H and <SUP>14</SUP>C are pure beta emitters with half-lives of 12.3 and 5,730 years, respectively, these radionuclides should be chemically separated from other radionuclides present in radwastes for accurate quantification. In particular, a collection technique for <SUP>14</SUP>C radionuclide in radwastes is needed because it is converted into <SUP>14</SUP>CO<SUB>2</SUB> gas by an oxidation reaction. To confirm the recoveries of <SUP>3</SUP>H and <SUP>14</SUP>C, various standard radioactive sources were used to verify the proposed method. Because the majority of <SUP>3</SUP>H radionuclides are distributed in tritiated water (HTO), only tritiated water was used as a standard for <SUP>3</SUP>H radionuclides. Additionally, <SUP>14</SUP>C-labeled methanol (<SUP>14</SUP>CH<SUB>3</SUB>OH), lauric acid (<SUP>14</SUP>CH<SUB>3</SUB>(CH<SUB>2</SUB>)<SUB>10</SUB>COOH), sodium bicarbonate (NaH<SUP>14</SUP>CO<SUB>3</SUB>), and toluene (C<SUB>6</SUB>H<SUB>5</SUB><SUP>14</SUP>CH<SUB>3</SUB>) were used as <SUP>14</SUP>C standards. The compounds were oxidized with chemical oxidants and then separated. The individual species were mixed with a scintillation cocktail and counted using a liquid scintillation counter. The recoveries of <SUP>14</SUP>C and <SUP>3</SUP>H were 82-97% and 98%, respectively. The wet oxidation method will be applied to RI wastes for clearance.

Glycerol-fed microbial fuel cell with a co-culture of Shewanella oneidensis MR-1 and Klebsiella pneumonae J2B

Kim, C.,Song, Y. E.,Lee, C. R.,Jeon, B. H.,Kim, J. R. SPRINGER 2016 Journal of industrial microbiology & biotechnology Vol.43 No.10

<P>Glycerol is an attractive feedstock for bioenergy and bioconversion processes but its use in microbial fuel cells (MFCs) for electrical energy recovery has not been investigated extensively. This study compared the glycerol uptake and electricity generation of a co-culture of Shewanella oneidensis MR-1 and Klebsiella pneumonia J2B in a MFC with that of a single species inoculated counterpart. Glycerol was metabolized successfully in the co-culture MFC (MFC-J&M) with simultaneous electricity production but it was not utilized in the MR-1 only MFC (MFC-M). A current density of 10 mA/m(2) was obtained while acidic byproducts (lactate and acetate) were consumed in the co-culture MFC, whereas they are accumulated in the J2B-only MFC (MFC-J). MR-1 was distributed mainly on the electrode in MFC-J&M, whereas most of the J2B was observed in the suspension in the MFC-J reactor, indicating that the co-culture of both strains provides an ecological driving force for glycerol utilization using the electrode as an electron acceptor. This suggests that a co-culture MFC can be applied to electrical energy recovery from glycerol, which was previously known as a refractory substrate in a bioelectrochemical system.</P>

Ferroelectric properties of Mn-doped BiFeO₃ thin films

Lee, M.H.,Park, J.S.,Kim, D.J.,Cho, H.J.,Sung, Y.S.,Kim, M.H.,Cho, J.H.,Choi, H.I.,Do, D.,Kim, W.J.,Kim, S.S.,Choi, B.C.,Song, T.K. Elsevier 2011 CURRENT APPLIED PHYSICS Vol.11 No.3

Bi(Fe<SUB>0.99</SUB>Mn<SUB>0.01</SUB>)O<SUB>3</SUB> thin films were prepared on a Pt(111)/Ti/SiO<SUB>2</SUB>/Si(100) substrates by pulsed laser deposition at various deposition temperature, such as at 520 <SUP>o</SUP>C, 530 <SUP>o</SUP>C, and 540 <SUP>o</SUP>C, respectively. The film deposited at 540 <SUP>o</SUP>C exhibited better ferroelectric property such as large remnant polarization (2P<SUB>r</SUB> = 139 μC/cm<SUP>2</SUP>) and low coercive field (2E<SUB>c</SUB> = 630 kV/cm). However, high leakage current density was observed especially in a high electric field range. The improvements were attributed to the facts of highly (111)-preferred orientation and uniform large grain size when the film was deposited at 540 <SUP>o</SUP>C.