• 제목/요약/키워드: Biomaterial science

검색결과 393건 처리시간 0.034초

Corrosion Behavior of Ti-13Nb-13Zr and Ti-6Al-4V Alloys for Biomaterial Application

  • Saji, Viswanathan S.;Jeong, Yong-Hoon;Yu, Jin-Woo;Choe, Han-Cheol
    • Corrosion Science and Technology
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    • 제9권1호
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    • pp.12-15
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    • 2010
  • Ti-13Nb-13Zr (TNZ) alloy has attracted considerable research attention in the last decade as a suitable substitute for the commercially used Ti-6Al-4V (TAV) alloy for orthopedic and dental implant applications. Hence, in the present work, a comparative evaluation has been performed on the electrochemical corrosion behavior of TNZ and TAV alloys in 0.9 wt.% NaCl solution. The result of the study showed that both the alloys had similar electrochemical behavior. The corrosion resistance of TAV alloy is found to be marginally superior to that of TNZ alloy.

국내 특수 생태환경의 탈질 저영양 세균의 종 다양성 및 생리적 특성 분석 (Analysis of Species Variety and Physiological Characteristics of Denitrifying Oligotrophic Bacteria Isolated from the Specific Environment in Korea)

  • 이창묵;원항연;권순우;강한철;구본성;윤상홍
    • 한국미생물·생명공학회지
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    • 제39권3호
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    • pp.210-217
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    • 2011
  • 국내의 대표적 섬이나 생태환경이 잘 보존된 토양으로부터 저영양세균 3,471주를 분리하였고 이로부터 질소발생 분석법에 의해 탈질균 135주를 최종 선발하였다. 이들 균주의 16S rDNA를 염기서열 분석한 결과 이들의 90% 가량이 Proteobacterium문에 속하였으며 다른 44속에 대부분 포함되었다. 대표적인 44속에 대해 분자생물학적 동정을 한 후 다양한 외부환경(온도, pH, 염, 무기질소염) 조건에 대한 이들의 생존성 범위를 조사한 결과, 넓은 온도($4^{\circ}C{\sim}42^{\circ}C$)와 pH(4~10)범위에서 자랄 수 있는 탈질균 12종을 최종 선발하였다.

열처리 온도가 Poly(trimethylene terephthalate)(PTT) 섬유의 역학적 성질과 미세구조에 미치는 효과 (The Effects of Annealing Temperature on The Physical Properties and Fine Structure of Poly(trimethylene terephthalate)(PTT) Fibers)

  • 정경희;이언필;이재호
    • 한국의류산업학회지
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    • 제15권6호
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    • pp.985-992
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    • 2013
  • Polytrimethylene terephthalate(PTT) offers several advantageous properties such as good tensile strength, uniformity, stiffness, toughness, UV stability, resilience, stain resistance, outstanding elastic recovery, and dyeability. The effects of annealing temperature on physical properties and the structure of PTT filaments and yarn were investigated by measuring wide-angle X-ray diffraction (WAXD), density, optical birefringence, dynamic visco elasticity, and tensile testing. The intensity of maximum tan ${\delta}$ decreased and the temperature of maximum tan ${\delta}$ shifted to a higher temperature as the annealing temperature of filaments increased; however, it shifted to a lower temperature when the annealing temperature exceeded $130^{\circ}C$. In addition, crystallinity, density and D-spacing of (010) crystal face increased as the annealing temperature increased. Optical birefringence and specific stress were almost constant up to $100^{\circ}C$ and then decreased above $130^{\circ}C$. The shrinkage of PTT filament is 0 in boiling water when annealed above $130^{\circ}C$; consequently, the use of annealed fiber above $130^{\circ}C$ can remove thermal instability when dyeing PTT fiber. In the case of yarns, the thermal stability and physical properties of yarns showed the best effect when the ply number is less than 5, twist number is less than 400tpm, and the annealing time is 20minutes.

Synthesis and Evaluation of F-18 Labeled 2'-Deoxy-2'-fluoro-5-methyl-1-β-L-arabinofuranosyluracil (L-[18F]FMAU)

  • Jo, Nam-Hyun;Moon, Byung-Seok;Hong, Su-Hee;An, Gwang-Il;Choi, Tae-Hyun;Cheon, Gi-Jeong;Cho, Jung-Hyuck;Yoo, Kyung-Ho;Lee, Kyo-Chul;Oh, Chang-Hyun
    • Bulletin of the Korean Chemical Society
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    • 제28권12호
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    • pp.2449-2453
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    • 2007
  • L-[18F]FMAU ([18F]1b) was prepared from the precursor 2-O-[(trifluoromethyl)-sulfonyl]-1,3,5-tri-Obenzoyl- α-L-ribofuranose, by coupling the radioactive fluoro-sugar with the corresponding silylated thymine in 4 steps. The final products, including the α and β anomers, were purified using reverse phase HPLC with an appropriate solvent (5% CH3CN/H2O) at a flow rate of 3.0 mL/min. The total elapsed time of synthesis was about 180-200 min from EOB. The α/β anomeric ratio of the compounds was about 1:9, and the radiochemical purity of the product (β-form) was >98% with decay-corrected yields of 25-35%. All radioactive samples were confirmed using co-injection with pure non-radioactive analogues in every step. In the cellular uptake in vitro test of herpes simplex virus-thymidine kinase (HSV1-TK) gene expressed cells, the percent uptake of injected dose (%ID) of L- and D-FMAU was 37.28 and 65.86, respectively after 240 min incubation. However, the relative uptake (MCA-TK/MCA cellular uptake ratio) of L-FMAU was higher than that of D-FMAU (%ID of L-FMAU, 0.36 and D-FMAU, 0.93 after 240 min incubation in MCA cells). This means that L-FMAU will show better specific HSV1-TK gene expressed cell uptake for selective HSV1-TK gene imaging.