• Title/Summary/Keyword: biomaterials

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Vibration Analysis of Gearbox for Agricultural UTV using a Reduced-Order Model (축소 모델 기법을 이용한 농업용 전동식 동력운반차 감속기의 진동 분석)

  • Kim, Beom-Soo;Cho, Seung-Je;Shin, In-Kyung;Chung, Woo-Jin;Han, Hyun-Woo;Kim, Ji-Tae;Park, Young-Jun
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.18 no.8
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    • pp.8-17
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    • 2019
  • In this study, a model reduction technique was used to develop a precise noise and vibration prediction model for the individual components of a driveline system. The dynamic reduced-order model generated by the Craig-Bampton method was applied to perform dynamic analysis of an electric agricultural power cart. The natural frequency and acceleration response results were analyzed according to the different number of dominant sub-structural modes contained in the reduced-order models. Through the analysis results, it was confirmed that a sufficient number of dominant sub-structures to satisfy the operating conditions should be selected to construct an optimal reduced-order model.

Acetate decreases PVR/CD155 expression via PI3K/AKT pathway in cancer cells

  • Tran, Na Ly;Lee, In Kyu;Choi, Jungkyun;Kim, Sang-Heon;Oh, Seung Ja
    • BMB Reports
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    • v.54 no.8
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    • pp.431-436
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    • 2021
  • In recent years, restoring anti-tumor immunity has garnered a growing interest in cancer treatment. As potential therapeutics, immune checkpoint inhibitors have demonstrated benefits in many clinical studies. Although various methods have been applied to suppress immune checkpoints to boost anti-tumor immunity, including the use of immune checkpoint inhibitors, there are still unmet clinical needs to improve the response rate of cancer treatment. Here, we show that acetate can suppress the expression of poliovirus receptor (PVR/CD155), a ligand for immune checkpoint, in colon cancer cells. We demonstrated that acetate treatment could enhance effector responses of CD8+ T cells by decreasing the expression of PVR/CD155 in cancer cells. We also found that acetate could reduce the expression of PVR/CD155 by deactivating the PI3K/AKT pathway. These results demonstrate that acetate-mediated expression of PVR/CD155 in cancer cells might potentiate the anti-tumor immunity in the microenvironment of cancer. Our findings indicate that maintaining particular acetate concentrations could be a complementary strategy in current cancer treatment.

Biodegradable sheath-core biphasic monofilament braided stent for bio-functional treatment of esophageal strictures

  • Han, Cheol-Min;Lih, Eugene;Choi, Seul-Ki;Bedair, Tarek M.;Lee, Young-Jae;Park, Wooram;Han, Dong Keun;Son, Jun Sik;Joung, Yoon Ki
    • Journal of Industrial and Engineering Chemistry
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    • v.67
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    • pp.396-406
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    • 2018
  • In this study, a polydioxanone (PDO) and poly(L-lactic acid) (PLLA) sheath-core biphasic monofilament was designed to develop an esophageal stent with improved mechanical properties and controlled biodegradability. The radial force of PDO/PLLA sheath-core stent was 10.24 N, while that of PDO stent was 5.64 N. Deteriorations of tensile strength, elastic modulus and elongation during degradation test were also delayed on PDO/PLLA group. Hyaluronic acid-dopamine conjugate and $BaSO_4/PDO$ conjugate coating layers provided improved tissue adhesion strength and reasonable X-ray contrast, respectively. Taken all together, the sheath-core filaments with tissue adhesive and radiopaque properties will be useful in designing esophageal stents.

The Electrochemical Characteristics of Anodized Ti-29Nb-xZr Alloys

  • Lee, Kang;Choe, Han-Choel;Ko, Yeong-Mu
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2009.05a
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    • pp.219-219
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    • 2009
  • In this study, electrochemical impedance characteristics of anodic oxide layer formed on titanium ternary alloy surface have been investigated, Titanium oxide layers were grown on Ti-29Nb-xZr(x=3, 5, 7, 10 and 15 wt%) alloy substrates using phosphoric acid electrolytes.

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Synthesis and in vitro Activity of Novel 1β-Methylcarbapenems Having Spiro[2,4]heptane Moieties. Part II

  • Park, Hyeong-Beom;Jung, Myung-Ho;Cho, Jung-Hyuck;Oh, Chang-Hyun
    • Bulletin of the Korean Chemical Society
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    • v.29 no.8
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    • pp.1472-1478
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    • 2008
  • The synthesis of a new series of 1$\beta$-methylcarbapenems having spiro[2,4]heptane moieties is described. Their in vitro antibacterial activities against both Gram-positive and Gram-negative bacteria were tested and the effect of substituents at the pyrrolidine ring was investigated. Most of the compounds were found to be more active compared to imipenem against Gram-negative bacteria. A particular compound (IIIc) having 7-oxo-5- azaspiro[2,4]heptane moiety showed the most potent antibacterial activity.