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Cytoprotective effect of Eriobotrya japonica L. against the iron-induced oxidative stress through AMPK activation (AMPK 활성화를 통한 중금속 유발 산화적 스트레스에 대한 비파엽의 세포 보호 효과)

  • Min-Jin Kim;Young-Eun Kim;Seon Been Bak;Su-Jin Bae;Kwang-Il Park;Sun-Dong Park;Young Woo Kim
    • Herbal Formula Science
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    • v.32 no.1
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    • pp.99-109
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    • 2024
  • Objectives : In this study, we investigated the cytoprotective effect of Eriobotrya japonica L. (EJ) extract against Arachidonic acid (AA)+iron-induced oxidative stress. Methods : To confirm the cytoprotective effect of EJ against AA+iron-induced oxidative stress in HepG2 cells, it was evaluated by MTT assay, immunoblot anaylsis, and Calcein-AM/propidium iodide (PI) staining. Additionally, the mechanism of action of the cytoprotective effect was evaluated through molecular mechanisms. Results : EJ (100 ㎍/mL) inhibited Arachidonic acid (AA)+iron-induced cell death in a concentration-dependent manner. It also inhibited AA+iron-induced mitochondrial dysfunction and ROS production. EJ activated the LKB1-AMPK signaling pathway. Conclusions : In conclusion, EJ has the ability to protect liver cells from oxidative stress, indicating that it is related to AMPK-LKB1 signaling pathways.

The preparation of $YBa_2Cu_3O_x$ superconducting thin film using rf - magnetron sputtering system (Rf - magnetron sputtering system을 사용한 $YBa_2Cu_3O_x$ 초전도 박막의 제조)

  • Park, S.J.;Kim, M.K.;Choi, S.H.;Choi, H.S.;Hwang, J.S.;Han, B.S.
    • Proceedings of the KIEE Conference
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    • 1992.07b
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    • pp.717-720
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    • 1992
  • Since the discovery of High-Tc superconducting Y-Ba-Cu-O ceramics with critical temperature of about 90K, numerous efforts to prepare supercond ucting thin films with excellent qualities such as High-Tc and critical current density have been made. The samples were deposited onto $SiO_x$ substrates heated at 540$^{\circ}C$ - 600$^{\circ}C$ in a single target rf - magnetron sputtering system. The film thickness has 2000$\AA$ - 5000 $\AA$ with a rate of 16 $\AA$/min. and distance between target and substrate was 50 mm. The films were characterized by X - ray diffraction, scanning electron microscopy and critical temperature.

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Different Functional and Structural Characteristics between ApoA-I and ApoA-4 in Lipid-Free and Reconstituted HDL State: ApoA-4 Showed Less Anti-Atherogenic Activity

  • Yoo, Jeong-Ah;Lee, Eun-Young;Park, Ji Yoon;Lee, Seung-Taek;Ham, Sihyun;Cho, Kyung-Hyun
    • Molecules and Cells
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    • v.38 no.6
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    • pp.573-579
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    • 2015
  • Apolipoprotein A-I and A-IV are protein constituents of high-density lipoproteins although their functional difference in lipoprotein metabolism is still unclear. To compare anti-atherogenic properties between apoA-I and apoA-4, we characterized both proteins in lipid-free and lipidbound state. In lipid-free state, apoA4 showed two distinct bands, around 78 and $67{\AA}$ on native gel electrophoresis, while apoA-I showed scattered band pattern less than $71{\AA}$. In reconstituted HDL (rHDL) state, apoA-4 showed three major bands around $101{\AA}$ and $113{\AA}$, while apoA-I-rHDL showed almost single band around $98{\AA}$ size. Lipid-free apoA-I showed 2.9-fold higher phospholipid binding ability than apoA-4. In lipid-free state, $BS_3$-crosslinking revealed that apoA-4 showed less multimerization tendency upto dimer, while apoA-I showed pentamerization. In rHDL state (95:1), apoA-4 was existed as dimer as like as apoA-I. With higher phospholipid content (255:1), five apoA-I and three apoA-4 were required to the bigger rHDL formation. Regardless of particle size, apoA-I-rHDL showed superior LCAT activation ability than apoA-4-rHDL. Uptake of acetylated LDL was inhibited by apoA-I in both lipid-free and lipid-bound state, while apoA-4 inhibited it only lipid-free state. ApoA-4 showed less anti-atherogenic activity with more sensitivity to glycation. In conclusion, apoA-4 showed inferior physiological functions in lipid-bound state, compared with those of apoA-I, to induce more pro-atherosclerotic properties.

Structures and N→Si Bond Characters of 1-Fluorosilatrane and the Silatranyl Cation

  • Lee, Hyo-Sug;Bae, Cheol-Beom;Do, Young-Kyu;Lee, Yoon-Sup
    • Bulletin of the Korean Chemical Society
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    • v.23 no.2
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    • pp.215-220
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    • 2002
  • The structures of 1-fluorosilatrane and the silatranyl cation were calculated by Hartree-Fock (HF), Mofller-Plesset second order (MP2), and various density functional theory (DFT) methods using many different basis sets, demonstrating that the Si-N bonds in two species are quite different. The N${\rightarrow}$Si bond distance of 1-fluorosilatrane from the hybrid DFT calculations $({\sim}2.32{\AA})$ using the Perdew-Wang correlation functional agrees with the gas phase experimental value $(2.324{\AA})$, while other functionals yield larger distances. The MP2 bond distance (2.287${\AA}$ with 6-311$G^{\ast}$) is shorter, and the HF one (2.544 ${\AA}$ with 6-311$G^{\ast}$) larger than those of DFT calculations. The MP2 bond distance is in good agreement with experiment indicating that the electron correlations are crucial for the correct description of the N${\rightarrow}$Si interaction. The silatranyl cation is a stable local minimum on the potential energy surface in all methods employed suggesting that the cation could be a reaction intermediate. The Si-N bond length for the cation is about 1.87 ${\AA}$ for all calculations tested implying that the Si-N bond is mainly conventional. Bonding characteristics of the Si-N bond in two species derived from the natural bond orbital analysis support the above argument based on calculated bond lengths.

Orthodontic bracket bonding to glazed full-contour zirconia

  • Kwak, Ji-Young;Jung, Hyo-Kyung;Choi, Il-Kyung;Kwon, Tae-Yub
    • Restorative Dentistry and Endodontics
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    • v.41 no.2
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    • pp.106-113
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    • 2016
  • Objectives: This study evaluated the effects of different surface conditioning methods on the bond strength of orthodontic brackets to glazed full-zirconia surfaces. Materials and Methods: Glazed zirconia (except for the control, Zirkonzahn Prettau) disc surfaces were pre-treated: PO (control), polishing; BR, bur roughening; PP, cleaning with a prophy cup and pumice; HF, hydrofluoric acid etching; AA, air abrasion with aluminum oxide; CJ, CoJet-Sand. The surfaces were examined using profilometry, scanning electron microscopy, and electron dispersive spectroscopy. A zirconia primer (Z-Prime Plus, Z) or a silane primer (Monobond-S, S) was then applied to the surfaces, yielding 7 groups (PO-Z, BR-Z, PP-S, HF-S, AA-S, AA-Z, and CJ-S). Metal bracket-bonded specimens were stored in water for 24 hr at $37^{\circ}C$, and thermocycled for 1,000 cycles. Their bond strengths were measured using the wire loop method (n = 10). Results: Except for BR, the surface pre-treatments failed to expose the zirconia substructure. A significant difference in bond strengths was found between AA-Z ($4.60{\pm}1.08MPa$) and all other groups ($13.38{\pm}2.57-15.78{\pm}2.39MPa$, p < 0.05). For AA-Z, most of the adhesive remained on the bracket. Conclusions: For bracket bonding to glazed zirconia, a simple application of silane to the cleaned surface is recommended. A zirconia primer should be used only when the zirconia substructure is definitely exposed.

Comparison of anterior maxillary and mandibular alveolar parameters in African American and Caucasian women: A retrospective pilot study

  • Renaud, Lauren;Gandhi, Vaibhav;West, Cailynn;Gudhimella, Sudha;Janakiraman, Nandakumar
    • Imaging Science in Dentistry
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    • v.51 no.2
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    • pp.175-185
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    • 2021
  • Purpose: The primary objective of this study was to analyze the thickness and height of alveolar bone around the maxillary and mandibular incisors. Additionally, this study aimed to compare bone parameters between Caucasian (CC) and African American (AA) female patients. Materials and Methods: In this retrospective pilot study, 50 female subjects(25 CC and 25 AA) were included. The inclusion criteria were AA or CC women between the ages of 18 and 50 with a normo-divergent facial pattern and Angle's class I, end-on class II, or mild class III malocclusion. The distance from the cementoenamel junction (CEJ) to the buccal and lingual alveolar crest; the alveolar ridge thickness at the mid-root and apex; and the buccal and lingual bone thickness at 3, 6, and 9mm from the CEJ were measured. Results: No significant difference was found (P>0.05) in the cortical bone thickness at 3mm, 6mm, or 9mm from the alveolar crest between CC and AA populations for most measurements. A significant difference in bone thickness was found (P<0.05) for the lingual surface of the central incisor, with maxillary bone thickness found to be higher than mandibular bone thickness. The measurements of lingual thickness were larger than those of buccal thickness for both races. Conclusion: There were no differences in maxillomandibular anterior alveolar bone measurements between normo-divergent adult AA and CC women, except for a few parameters at varying locations. However, future studies can be planned based the current pilot study data, which may provide valuable information.

Study on Optical Characteristics of Organic Light-emitting Diodes Using Two Fluorescence Dopants in Single Emissive Layer (2개의 형광 도판트를 적용한 단일발광층 유기발광소자의 광학적 특성 연구)

  • Kim, Tae-Gu;Oh, Hwan-Sool;Kim, You-Hyun;Kim, Woo-Young
    • Journal of the Korean Vacuum Society
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    • v.19 no.3
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    • pp.184-189
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    • 2010
  • Organic light-emitting diodes (OLEDs) with single emissive layer structures using two fluorescent dopants were fabricated and the device was composed of ITO / NPB ($700{\AA}$) / MADN : C545T - 1.0% : DCJTB - 0.3% ($300{\AA}$) / Bphen ($300{\AA}$) / LiF ($10{\AA}$) /Al ($1,000{\AA}$). C545T and DCJTB were functioned as green fluorescent dye and red fluorescent dye under MADN as host material. Concentrations of C545T and DCJTB was changed in emissive layer of MADN. Optimized OLED device using two fluorescence dopants shows emission efficiency of 8.42 cd/A and luminescence of 3169 cd/$m^2$at 6 V with CIE color coordinate, (0.43, 0.50). Electroluminescence of optimized OLED showed two peak at 500 and 564 nm according to C545T and DCJTB. These results indicate that F$\ddot{o}$ster energy transfer energy transfer was from MADN to C545T and rather than to DCJTB continuously.

Intake, Digestibility, Nitrogen and Energy Utilization by Korean Native Goats Consuming Alfalfa and Birdsfoot Trefoil (Alfalfa와 Birdsfoot Trefoil의 급여가 산양의 섭취량, 소화율과 질소 및 에너지 이용성에 미치는 영향)

  • Lee, In Duk;Lee, Hyung Suk;Kim, Deuk Soo
    • Journal of The Korean Society of Grassland and Forage Science
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    • v.18 no.4
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    • pp.317-322
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    • 1998
  • This study was conducted to compare the DM intake, the digestibility, and the utilization of nitrogen and energy of Korean native goats, when fed on orchardgrass supplemented with alfalfa or birdsfoot trefoil. Experimental diets included three treatments: orchardgrass(OG) 100%, orchardgrass 6%+alfalfa(AA) 40%(OG+AA), and orchardgrass 60%+birdsfoot trefoil(BT) 40%(OG+BT). The CP content was higher for OG+AA and OG+BT diets than for OG diets(P<0.05). The NDF content was high in OG diets(P<0.05) and the lignin content was high in OG+BT diets(P<0.05), but the ADF content did not differ among all diets. The DM intake and the digestibility of OM and cellular constituents were higher for OG+AA diets than for OG diets(P<0.05), but the NDF and ADF digestibility were not significant difference among all diets. The apparently digested N was higher for OG+AA diets than for other diets(P<0.05). However, the retained N % and biological value were higher for OG+BT diets than for OG diets(P<0.05), but those were not differ between OG+AA and OG+BT diets. On the other hand, the utilization of DE and ME did not show the difference among all diets. Based on the results, the utilization of nitrogen and energy was more improved for legume supplemented diets(AA, BT) than for OG diets(P<0.05). Furthermore, the utilization of nitrogen was slightly more improved for OG+BT diets than for OG+AA diets, but the significantly difference was not observed.

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Thin Film Gas Sensors Based on Tin Oxide for Acetonitrile (산화주석 기반의 아세토니트릴 검지용 박막형 가스센서)

  • Choi, Nak-Jin;Ban, Tae-Hyun;Kwak, Jun-Hyuk;Lim, Yeon-Tae;Joo, Byung-Su;Kim, Jae-Chang;Huh, Jeung-Soo;Lee, Duk-Dong
    • Journal of Sensor Science and Technology
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    • v.13 no.3
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    • pp.218-223
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    • 2004
  • Thin film gas sensor based on tin oxide was fabricated and its characteristics were examined. Target gas is acetonitrile ($CH_{3}CN$) that is simulant gas of blood agent gas. Sensing materials are $SnO_{2}$, $SnO_{2}$/Pt, and (Sn/Pt)oxidation with thickness from $1000{\AA}$ to $3000{\AA}$. Sensor was consisted of sensing electrode with interdigit (IDT) type in front side and a heater in back side. Its dimension was $7{\times}10{\times}0.6mm^{3}$. Fabricated sensor was measured as flow type and monitored real time using PC. The optimal sensing material for $CH_{3}CN$ was {Sn($3000{\AA}$)/Pt($30{\AA}$)}oxidation and its sensitivity and operating temperature were 30%, $300^{\circ}C$ in $CH_{3}CN$ 3 ppm.

Deposition and Characteristics of TiN Thin Films by Atomic Layer Epitaxy (ALE 법에 의한 TiN 박막의 증착 및 특성)

  • Kim, Dong-Jin;Jung, Young-Bae;Lee, Myung-Bok;Lee, Jung-Hee;Lee, Yong-Hyun;Hahm, Sung-Ho;Lee, Jong-Hwa
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.37 no.6
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    • pp.43-49
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    • 2000
  • The TiN thin films were deposited by ALE(atomic layer epitaxy) on (100) silicon substrate. The TiN thin films were characterized by means of XRD, 4-point probe, AFM, AES and SEM. TEMAT(terakis(ethyl methy lamino)titanium) and $NH_3$ were injected into the reactor in sequence of TEMAT-$N_2-NH_3-N_2$ to ensure a saturated surface reaction. As a result, the depostion rate of the TiN film was controlled by self-limiting growth mechanism at temperature range form 150 to 220 $^{\circ}C$. Deposited TiN films, all of which show amorphous structure, had a fixed deposition rate of 4.5 ${\AA}$/cycle. The resistivity of 210 ~ 230 ${\mu}{\Omega}{\cdot}$cm and the surface r.m.s. roughness of 7.9 ~ 9.3 ${\AA}$ were measured. When TiN film of 2000 ${\AA}$ were deposited, a excellent step coverage were observed in a trench structure of 0.43${\mu}m$ contacts with 6:1 aspect ratio.

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