Experimental evidence of hydrogen-oxygen decoupled diffusion into BaZr_0.6Ce_0.25Y_0.15O_3-δ

Lim, D.K.,Im, H.N.,Jeon, S.Y.,Park, J.Y.,Song, S.J. Elsevier Science 2013 ACTA MATERIALIA Vol.61 No.4

The electrical properties of BaZr<SUB>0.6</SUB>Ce<SUB>0.25</SUB>Y<SUB>0.15</SUB>O<SUB>3-δ</SUB> (BZCY) were studied as a function of both oxygen partial pressure (-2.65≤log(P<SUB>O'2</SUB>atm<SUP>-1</SUP>)≤-0.62) and water vapor activity (-3.33≤log(P<SUB>H'2O</SUB>atm<SUP>-1</SUP>≤-1.3)) in the temperature range of 973-1073K. The total conductivity slightly increased in reducing atmospheres with increasing water vapor activity because of the relative contribution to the total conductivity by the redox reaction at the given thermodynamic conditions. The partial conductivities of protons, holes and oxygen vacancies were successfully calculated, and the activation energy determined for proton transport was 0.3+/-0.1eV. The chemical diffusivity of oxygen at a fixed water vapor activity, D~<SUB>vO</SUB>, could only be evaluated from Fick's second law during oxidation and reduction at the fixed water vapor activity. However, twofold nonmonotonic conductivity relaxation behaviors were clearly confirmed in the temperature range investigated during hydration/dehydration. If P<SUB>O'2</SUB> represents the fixed oxygen partial pressure, D~<SUB>iH</SUB> is the hydrogen chemical diffusivity at P<SUB>O'2</SUB> and D~<SUB>vH</SUB> is the oxygen chemical diffusivity at P<SUB>O'2</SUB>, it was observed that D~<SUB>iH</SUB>>D~<SUB>vH</SUB> at all experimental conditions, suggesting that the hydrogen chemical diffusion is always faster than oxygen on hydration/dehydration in the temperature range studied.

Aqueous and dietary bioaccumulation of antibiotic tetracycline in D. magna and its multigenerational transfer

Kim, H.Y.,Jeon, J.,Hollender, J.,Yu, S.,Kim, S.D. Elsevier Scientific Pub. Co 2014 Journal of hazardous materials Vol.279 No.-

The potential bioaccumulation and distribution of antibiotics in non-target organisms have been inadequately studied in spite of their widespread occurrence in aquatic systems. We investigated the ability of tetracycline to bioaccumulate through aqueous and dietary routes in an aquatic organism, the freshwater crustacean Daphnia magna. D. magna was exposed to algal food (Pseudokirchneriella subcapitata) contaminated with tetracycline for dietary uptake. Tetracycline was transferred to D. magna more through aqueous uptake than through dietary uptake. The uptake rate constant of tetracycline for D. magna was k<SUB>in,water</SUB>=0.33+/-0.045 via the aqueous route and k<SUB>in,food</SUB>=0.16+/-0.012 via the dietary route for 1.0mgL<SUP>-1</SUP> tetracycline. Bioconcentration factors of 4.40+/-0.91Lkg<SUP>-1</SUP> and 3.66+/-0.50Lkg<SUP>-1</SUP> for 0.1 and 1.0mgL<SUP>-1</SUP> tetracycline were found for D. magna. The biomagnification factor of 0.19+/-0.04 indicates that magnification of tetracycline through the food web will not occur. The change in the internal concentration of the target compound was also studied for multigenerational (F1-F4) exposure. The internal concentration in D. magna showed a decreasing trend with increasing generations except for the parent generation. The bioaccumulation tendency showed a biphasic change in multigenerational exposure.

한우 경제형질에 미치는 Mitochondrial DNA D-loop 영역의 염기서열 변이효과

오재돈,윤두학,공홍식,임현진,이학교,조병욱,홍기창,전광주 한국동물자원과학회 2003 한국축산학회지 Vol.45 No.6

This study was performed to analyse the sequences of variations of mtDNA D-loop and their effects on carcass traits in Hnawoo(Korean cattle). The resulting sequences were compared with perviously published sequences for other cattle breeds(GenBank J01394). The PCR was used to amplify a total of 964 bp between nucleotide 15758 and 383 within D-loop region of mtDNA using specific primers. Twenty five polymorphic sites by nucleotide substitution were found in mtDNA of Hanwoo. The frequencies of positions at 169, 16042, 16093. 16119, 16255 and 16302 nt with high levels of sequence polymorphism were 0.891, 0.117, 0.109, 0.182, 0.197 and 0.117, respectively. The substitution effect at 169 and 16119 nt was found significant on marbling score. Also substitution effect at 169 and 16042 nt was highly significant(p<0.01) on backfat, thickness. Polymorphisrn of mtDNA sequence in D-loop region could be useful for the analysis of cytoplasmic genetic variation and associations with the other economically important traits and maternal lineage analysis in Hanwoo.

Integrin αvβ3-mediated transcriptional regulation of TIMP-1 in a human ovarian cancer cell line

Kim, D.S.,Jeon, O.H.,Lee, H.D.,Yoo, K.H.,Kim, D.S. Academic Press 2008 Biochemical and biophysical research communication Vol.377 No.2

We have previously reported that a disintegrin inhibits solid tumor growth and metastasis in mouse model [I.C. Kang, Y.D. Lee, D.S. Kim, A novel disintegrin salmosin inhibits tumor angiogenesis, Cancer Res. 59 (1999) 3754-3760; S.I. Kim, K.S. Kim, H.S. Kim, D.S. Kim, Y. Jang, K.H. Chung, Y.S. Park, Inhibitory effect of the salmosin gene transferred by cationic liposomes on the progression of B16BL6 tumors, Cancer Res. 63 (2003) 6458-462]. In this study, we have investigated the modulatory effect of a disintegrin, saxatilin, on the balance between MMP-9 and tissue inhibitor of metalloproteinase-1 (TIMP-1) in human ovarian cancer cell line MDAH 2774. Functional mechanism of the disintegrin-mediated transcriptional regulation of MMP-9 and TIMP-1 was examined in the ovarian cancer cell line. Saxatilin strongly induced TIMP-1 expression in dose- and time-dependent manners, while the disintegrin suppressed MMP-9 expression. Further analyses clearly indicated that interaction of the disintegrin and integrin αvβ3 results in the TIMP-1 promoter activation via c-fos to suppress TNF-α-induced cancer cell invasion. These results demonstrate that integrin αvβ3-mediated transcriptional regulation of MMP-9 and TIMP-1 is critical for suppressing the ovarian cancer cell invasion.

손상된 부르크막에 이식된 망막색소상피세포의 재유착성에 대한 세포외기질 단백의 영향

김광수,김유철,전세진,Kwang Soo Kim,M,D,Yu Cheol Kim,M,D,Se Jin Jeon,M,D 대한안과학회 2007 대한안과학회지 Vol.48 No.11

Purpose: To evaluate the effect of adding exogenous extracellular matrix (ECM) proteins on the reattachment of retinal pigment epithelium (RPE) to the damaged surface of Bruch`s membrane (BM). Methods: Porcine BM explants were divided into six groups: BMs with an intact basal lamina (bl-BM) and five damaged BMs (d-BM: bare & four ECM-coated). The d-BM was coated with ECM proteins (either fibronectin, laminin, collagen IV, or all). Primary RPE sheets were plated and cultured for each group of BM explants. The attached live cells were counted and examined with a scanning electron microscope after three days, as well as at 1, 2 and 4 weeks. Results: The RPE reattachment rate was highest in bl-BM and lowest in uncoated d-BM. ECM-coated groups showed a lower reattachment rate than bl-BM, but when compared with the uncoated group, the reattachment rate was significantly increased (p<0.05). ECM-exposure time did not influence the reattachment rate of any of the groups. RPE cells plated on bl-BMs and ECM-coated d-BMs attached and proliferated well and achieved confluence over time. Even though most cells were flat and large in shape, some cells revealed a good morphology with microvilli on their surface. On the other hand, only some of the RPE sheets plated on the uncoated d-BM attached loosely and most cells remained round and clumped. Conclusions: These results show that the addition of ECM proteins may increase the ability of RPE cells to reattach to the damaged BM surface, which would likely create a good morphology.

Cloning and characterization of phospholipase D from olive flounder (Paralichthys olivaceus)

Jeon, S.J.,Kim, M.S.,Ahn, S.J.,Seo, J.S.,Lim, S.U.,Sung, J.H.,Kim, N.Y.,Jeong, H.D.,Lee, H.H.,Chung, J.K. Academic Press 2008 Fish & shellfish immunology Vol.24 No.5

The phospholipase D1 (PLD1) cDNA, designated PoPLD, encoding a predicted protein of 1053 amino acids in olive flounder (Paralichthys olivaceus) has been cloned. The deduced amino acid sequence shares high identity with that of PLD1s and PLD2 in human, rat and mouse. The phylogenic analysis and sequence comparison of PoPLD with other PLD isozymes were found to be closely related to the PLD1 isozyme in primary structure. The tissue expression analysis of PoPLD showed that the mRNA of PoPLD was predominantly expressed in the brain, gullet, muscle, stomach, head kidney, pyloric caeca, intestine and gill. The expression of the PoPLD gene was examined in various tissues of flounder by RT-PCR following stimulation with LPS and compared also with that of the inflammatory cytokines IL-1β and IL-8 in various tissues of the stimulated flounder. This provides indirect evidence that PLD1 might have a relevant role in immune responses against pathogens and in inflammation. In addition, the recombinant protein of PoPLD (GFP-PoPLD), which demonstrated a phosphatidylcholine (PC)-hydrolyzing activity, was partially localized as a distinct ring-shaped form surrounding the rim of the nucleus in EPC cells. Together, our results suggest that PoPLD is similar to the mammalian PLD1 isoform, is generally widespread within olive flounder tissue, might have a relevant role in the fish immune system against pathogens and specifically may be localized in the subcellular membranes of the nuclear rim in EPC cells.

Lipase-catalyzed enantioselective synthesis of (R,R)-lactide from alkyl lactate to produce PDLA (poly D-lactic acid) and stereocomplex PLA (poly lactic acid)

Jeon, B.W.,Lee, J.,Kim, H.S.,Cho, D.H.,Lee, H.,Chang, R.,Kim, Y.H. Elsevier Science Publishers 2013 Journal of biotechnology Vol.168 No.2

R-lactide, a pivotal monomer for the production of poly (D-lactic acid) (PDLA) or stereocomplex poly (lactic acid) (PLA) was synthesized from alkyl ®-lactate through a lipase-catalyzed reaction without racemization. From among several types of lipase, only lipase B from Candida antarctica (Novozym 435; CAL-B) was effective in the reaction that synthesized (R,R)-lactide. Enantiopure (R,R)-lactide, which consisted of over 99% enantiomeric excess, was synthesized from methyl ®-lactate through CAL-B catalysis. Removal of the methanol by-product was critical to obtain a high level of lactide conversion. The (R,R)-lactide yield was 56% in a reaction containing 100mg of Novozym 435, 10mM methyl ®-lactate and 1500mg of molecular sieve 5A in methyl tert-butyl ether (MTBE). The important monomer (R,R)-lactide that is required for the production of the widely recognized bio-plastic PDLA and the PLA stereocomplex can be obtained using this novel synthetic method.

Al, Ag 박막에서 Electromigration과 Adhesion에 관한 연구

김대일(D.I. Kim),전진호(J.H. Jeon),박영래(Y.R. Park),최재승(J.S. Choi),김진영(J.Y. Kim) 한국진공학회(ASCT) 1992 Applied Science and Convergence Technology Vol.1 No.2

본 논문은 Al, Ag박막에서 엘렉트로마이그레이션 현상에 의한 힐록, 기공형성과 접착력에 대하여 연구하였다. Mo보트를 이용하여 1×10^(-7)Torr의 진공도에서 전자-빔 증착기로 현미경용 유리기판에 약 1000Å의 두께로 Al, Ag박막을 각각 증착하였다. Al, Ag박막에서 엘렉트로마이그레이션에 의한 결함을 연구하기 위하여 1×10^5(A/㎠) 의 d.c. 전류를 인가하였고 Scratch Method와 Tape Method로 Al과 Ag박막의 접착력을 측정하였다. 기공과 힐록, 그리고 스크레치 채널은 SEM과 광학현미경 사진을 이용하여 분석하였다. Al박막에서는 엘렉트로마이그레이션으로 힐록과 기공이 양극부분과 음극부분에서 각각 관찰되었다. 반면에 Ag박막에서는 Coulombic force에 의해 기공과 힐록이 양극부분과 음극부분에서 각각 형성되어 역엘렉트로마이그레이션 현상을 보였다. 접착력은 산소 친화력이 강한 Al박막에서 Ag박막 보다 크게 나타났다. The formation of hillocks and voids due to the electromigration and the adhesion force of Al and Ag thin films have been investigated. Thin films of 1000Å thickness were deposited onto slideglass substrates by electron-beam deposition system from Mo boats in a high vacuum in the range of 10^(-7)Torr. A constant d.c. current of 1×10^5(A/㎠) stressing has been stressed on Al and Ag thin films in order to observe the failures due to the electromigration. And the adhesion forces of Al and Ag thin films were measured by using scratch method and tape method. Hillocks and scratch channel were also characterized by utilizing scanning electron microscopy and optical microscope. In Al thin films, void formed near the negative region and hillocks formed near the positive region, which is mainly caused by the electron wind force. In contrast, Ag thin films resulted in the formation of voids near the positive region and hillocks near the negative region caused by Coulombic force. Al/glass showed stronger adhesion force than Ag/glass. This is believed to be due to the higher oxygen affinity of Al than that of Ag.

VDUP1 potentiates Ras-mediated angiogenesis via ROS production in endothelial cells.

Piao, Z H,Yoon, S R,Kim, M S,Jeon, J H,Lee, S H,Kim, T D,Lee, H G,Bae, K H,Min, J K,Chung, S J,Kim, M,Cho, Y S,Oh, D B,Park, S Y,Chung, J W,Choi, I R. Wegmann 2009 Cellular and molecular biology Vol.55 No.suppl

<P>Vitamin D3 up-regulated protein 1 (VDUP1) is a tumor suppressor of which expression is reduced in a variety of cancer cells, and enforced expression inhibits the tumor cell proliferation. It inhibits the activity of thioredoxin, thus contributing cellular ROS generation. Since ROS is a critical factor for angiogenesis, we investigated the role of VDUP1 in angiogenesis and endothelial proliferation. The expression of VDUP1 was upregulated by overexpression of an oncogene, Ras. Enforced expression of VDUP1 increases ROS production and proliferation of Ras-overexpressing endothelial cells. Overexpression of VDUP1 increases the resistance to the anchorage-dependent cell death and tube formation of the Ras-overexpressing endothelial cell. In addition, the removal of ROS by ROS scavenger attenuates the effect of VDUP1 on tube formation. These results suggest that VDUP1 is involved in Ras-mediated angiogenesis via ROS generation in endothelial cells.</P>

Tomographic 2-D X-ray imaging of toroidal fusion plasma using a tangential pinhole camera with gas electron multiplier detector

Song, I.,Jang, J.,Jeon, T.,Pacella, D.,Claps, G.,Murtas, F.,Lee, S.H.,Choe, W. Elsevier 2016 CURRENT APPLIED PHYSICS Vol.16 No.10

<P>A tangential X-ray pinhole camera based on a gas electron multiplier (GEM) detector was installed on KSTAR to study high temperature plasmas emitting X-ray photons in the energy band of 4-15 keV. The camera system consists of a triple-GEM gas chamber with a readout printed circuit board and a pinhole to image the plasma in two dimensions (2-D). The advantages of this tangential camera system include its compactness, high efficiency, energy discrimination in bands, and selectivity of the photon energy range etc. This camera system allows a selection of the viewing area through a remote control of the entire setup. The Philips-Tikhonov algorithm for tangential reconstruction was used to visualize the poloidal cross-sectional images. Phantom tests were performed with synthetic D-shaped plasma images and a comparison with the magnetic equilibrium flux surfaces from the real-time EFIT code obtaining a good agreement between each other. The 2-D X-ray images of the KSTAR plasma were successfully acquired during sawtooth crash, electron cyclotron heating, vertical displacement event, and emissivity from the injected trace Ar impurity. (C) 2016 Elsevier B.V. All rights reserved.</P>