• Title, Summary, Keyword: bioactivity

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Effect of Some Factors on the Production of an Antifungal Compound KRF-001 from Bacillus subtilis subsp. krictiensis (Bacillus subtilis subsp. krictiensis로부터 항진균물질 KRF-001의 생산을 위한 발효조건 및 돌연변이 연구)

  • 손광희;권혜경;복성해;이항우
    • Microbiology and Biotechnology Letters
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    • v.19 no.6
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    • pp.614-618
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    • 1991
  • Antifungal compound, KRF-001, was produced by Bacillus subtilis subsp. krictiensis isolated from soil. Physico-chemical factors affecting cell growth and bioactivity were examined to improve the production yield. Nutrient composition, temperature, pH and phosphate ion concentration were proved to be important factors for the production of KRF-001. Mutation was performed to select high yielding strains. First, mutation was performed with ultra-violet light, and the second mutation process was conducted by MNNG (N-Methyl-N'-nitro-N-nitrosoguanidine) resulting in three high yielding strains.

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Effect of Surface Treatment on Bioactivity of Ti-Ni Shape Memory Alloys (Ti-Ni형상기억합금의 생체활성에 미치는 표면처리의 영향)

  • Choi, Mi-Seon;Nam, Tae-Hyun
    • Korean Journal of Metals and Materials
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    • v.47 no.12
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    • pp.881-886
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    • 2009
  • Research into the replacement of injured systems and tissue in the human body is advancing rapidly. Recently, Ti-Ni shape memory alloys have shown excellent biofunctionality related to their shape memory effect and superelasticity. In this study, the effect of an acid or an alkali treatment on the bioactivity in 49Ti-Ni and 51.5Ti-48.5Ni alloys is investigated in an effort to utilize Ti-Ni alloy as a biomaterial. In addition, the biocompatibility in a SBF solution is assessed through in vitro testing. A porous surface was formed on the surface of both alloys after a chemical treatment. According to the in vitro test, apatite formed on the surfaces of both alloys. The forming rate of apatite in the Ti-rich alloy was faster that in the Ni-rich alloy. The formation of apatite provided proof of the bioactivity of the Ti-Ni alloy. A small quantity of Ni was eluted at the initial stage, whereas Ni was not found for 12 days in the Ti-rich alloy and for 8 days in the Ni-rich alloy. In the case of the treated 51.5Ti-Ni alloy, the shape memory property was worsened but the biocompatibility was improved.

Long-acting Recombinant Human Granulocyte Colony Stimulating Factor (rhG-CSF) with a Trimer-Structured Polyethylene Glycol

  • Jo, Yeong-Woo;Lee, Mee-Yong;Choi, Yun-Kyu;Lee, Sung-Hee;Kang, Soo-Hyoung;Na, Kun;Youn, Yu-Seok;Choi, Eung-Chil
    • Journal of Pharmaceutical Investigation
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    • v.40 no.6
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    • pp.379-386
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    • 2010
  • Mono PEGylated rhG-CSF (PEG-G-CSF) prepared by utilizing unique PEG was purified and characterized by cation-exchange chromatography. A unique, trimer-structured PEG was chosen for PEGylation of rhG-CSF among various PEG moieties. The in-vitro bioactivity, stability, and pharmacokinetics of mono-PEG-G-CSF were examined and compared to those of native rhG-CSF. Mono PEG-G-CSF exhibited reduced in-vitro bioactivity to native rhG-CSF but showed an excellent in-vivo bioactivity and stability. Furthermore, it showed markedly reduced clearance in rats, thereby increasing the biological half-life by about 4.5-fold compared to that of native rhG-CSF. The results suggest that this unique, trimer-structured 23 kDa PEG can provide advantages to improve the bioactivity of therapeutic proteins in clinical use.

Evaluation of Bioactivity of Ti-6Al-7Nb Alloys with Various Hydrothermal Treatment Times (열수처리 시간에 따른 Ti-6Al-7Nh 합금의 생체활성 평가)

  • Kwon O. S.;Choi S. K.;Park K. B.;Lee M. H.;Bae T. S.;Lee O. Y.
    • Korean Journal of Materials Research
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    • v.14 no.12
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    • pp.876-884
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    • 2004
  • This study was to investigate whether the bioactivity of the anodized and hydrothermally treated Ti-6Al-7Nb alloy were affected by the time of hydrothermal treatment. Anodizing was performed at current density 30 $mA/cm^2$ up to 300 V in electrolyte solutions containing $DL-{\alpha}-glycerophosphate$ disodium salt hydrate $(DL-{\alpha}-GP)$ and calcium acetate (CA). Hydrothermal treatment was done at $300^{\circ}C$ for 30 min, 1 hr, 2 hrs, and 4 hrs to produce a thin film layer of hydroxyapatite (HA). The bioactivity was evaluated from HA formation on the surfaces in a Hanks' solution with pH 7.4 at $36.5^{\circ}C$ for 10, 20, and 30 days. Anodic oxide films were porous with pore size of $1\sim4{\mu}m\;and\;3\sim4{\mu}m$ thickness. The anodic oxide films composed with strong anatase peak with presence of rutile peak, and showed the increase in intensity of anatase peak after hydrothermal treatment. It was shown that the intensity of anatase peak increased with increasing the time of hydrothermal treatment but was no difference in rutile peak. The corrosion voltage was the highest in the group of hydrothermal treatment for 2 hrs (Ecorr: -338.6 mV). The bioactivity in Hank's solution was accelerated with increasing the time of hydrothermal treatment.

Quantitative-Structure Activity Relationship (QSAR) Model for Abuse-liability Evaluation of Designer Drugs (합성마약류의 의존성 평가를 위한 구조활성상관(QSAR) 모델 적용)

  • Yun, Jaesuk
    • YAKHAK HOEJI
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    • v.58 no.1
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    • pp.53-57
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    • 2014
  • In recent, the abuse of newly-emerging psychoactive drugs, ('designer drugs') is a rapidly increasing problem in Korean society. Quantitative-structure activity relationship (QSAR) is an alternative method to predict bioactivities of new abused compounds. In this study, cathinone-related new designer drugs, 4-methylbuphedrone and 4-methoxy-N,N-dimethylcathinone were tested for prediction of the bioactivity with QSAR model. The bioactivity of 4-methylbuphedrone and 4-methoxy-N,N-dimethylcathinone was similar to those of methylone. These results suggest that the prediction with QSAR model may provide scientific evidences for regulatory decision.

Chemical Constituents of the Himalayan Yew, A Review

  • Das, Biswanath;Anjani, G.
    • Natural Product Sciences
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    • v.4 no.4
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    • pp.185-202
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    • 1998
  • A large number of chemical constituents have been reported from the Himalayan yew [Taxus baccata (Linn) or T. wallichiana (Zucc)]. These constituents are mainly taxoids and phenolics. Taxol, a lead anticancer agent, is the most important constituent. Other compounds have also been found to possess interesting biological properties. The literature concerning the chemistry and bioactivity of the constituents of the Himalayan yew has been briefly reviewed.

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Synthesis and Bioactivity of Quercetin Aspirinates

  • Lu, Chenjuan;Huang, Feng;Li, Zexin;Ma, Jinshuo;Li, Huanhuan;Fang, Lizhen
    • Bulletin of the Korean Chemical Society
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    • v.35 no.2
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    • pp.518-520
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    • 2014
  • Hybrids of some natural compounds are promising to obtain new leads with good biological activities for drug discovery. Three quercetin aspirinates were synthesized by esterification of the 3-and 7-hydroxyl groups of quercetin with aspirin. Biological activities of these quercetin aspirinates were initially screened and showed better cytotoxic activities against tumor cell lines HL-60 and HepG2 and less scavenging activity against DPPH than the quercetin respectively.

Change in concentration and bioactivity of soil-applied pretilachlor under various soil moisture conditions (다양한 토양수분조건에 처리한 pretilachlor의 농도 및 활성 변화)

  • Lee, Do-Jin
    • The Korean Journal of Pesticide Science
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    • v.3 no.2
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    • pp.81-85
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    • 1999
  • Concentration change of soil-applied pretilachlor (2-chloro-2',6'-diethyl- N-2-propoxyethyl)-actanilide) was investigated under upland condition with various soil moisture contents ranging from 50 to 80%(water content by weight). Following pretilachlor from each soil solution was extracted by centrifugation using double tubes, its concentration was determined by HPLC. Pretilachlor concentration in the soil solutions were almost the same under various soil moisture conditions. However, the total amount of pretilachlor increased as the soil moisture content increased. With increasing soil moisture content, the bioactivity of soil-applied pretilachlor on inhibiting the growth of Echinochloa ultilis Ohwi et Yabuno and the absorption of $^{14}C$-pretilachlor in its plants were also enhanced. Our results demonstrate that the absorption of pretilachlor in plants varies with soil moisture content and thus the bioactivity of soil-applied pretilachlor on inhibiting plant growth is different under various soil moisture conditions at the same dosage based on air-dried weight.

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Role of Ca in Modifying Corrosion Resistance and Bioactivity of Plasma Anodized AM60 Magnesium Alloys

  • Anawati, Anawati;Asoh, Hidetaka;Ono, Sachiko
    • Corrosion Science and Technology
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    • v.15 no.3
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    • pp.120-124
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    • 2016
  • The effect of alloying element Ca (0, 1, and 2 wt%) on corrosion resistance and bioactivity of the as-received and anodized surface of rolled plate AM60 alloys was investigated. A plasma electrolytic oxidation (PEO) was carried out to form anodic oxide film in $0.5mol\;dm^{-3}\;Na_3PO_4$ solution. The corrosion behavior was studied by polarization measurements while the in vitro bioactivity was tested by soaking the specimens in Simulated Body Fluid (1.5xSBF). Optical micrograph and elemental analysis of the substrate surfaces indicated that the number of intermetallic particles increased with Ca content in the alloys owing to the formation of a new phase $Al_2Ca$. The corrosion resistance of AM60 specimens improved only slightly by alloying with 2 wt% Ca which was attributed to the reticular distribution of $Al_2Ca$ phase existed in the alloy that might became barrier for corrosion propagation across grain boundaries. Corrosion resistance of the three alloys was significantly improved by coating the substrates with anodic oxide film formed by PEO. The film mainly composed of magnesium phosphate with thickness in the range $30-40{\mu}m$. The heat resistant phase of $Al_2Ca$ was believed to retard the plasma discharge during anodization and, hence, decreased the film thickness of Ca-containing alloys. The highest apatite forming ability in 1.5xSBF was observed for AM60-1Ca specimens (both substrate and anodized) that exhibited more degradation than the other two alloys as indicated by surface observation. The increase of surface roughness and the degree of supersaturation of 1.5xSBF due to dissolution of Mg ions from the substrate surface or the release of film compounds from the anodized surface are important factors to enhance deposition of Ca-P compound on the specimen surfaces.

Enhanced compatibility and initial stability of Ti6Al4V alloy orthodontic miniscrews subjected to anodization, cyclic precalcification, and heat treatment

  • Oh, Eun-Ju;Nguyen, Thuy-Duong T.;Lee, Seung-Youp;Jeon, Young-Mi;Bae, Tae-Sung;Kim, Jong-Gee
    • The korean journal of orthodontics
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    • v.44 no.5
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    • pp.246-253
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    • 2014
  • Objective: To evaluate the bioactivity, and the biomechanical and bone-regenerative properties of Ti6Al4V miniscrews subjected to anodization, cyclic precalcification, and heat treatment (APH treatment) and their potential clinical use. Methods: The surfaces of Ti6Al4V alloys were modified by APH treatment. Bioactivity was assessed after immersion in simulated body fluid for 3 days. The hydrophilicity and the roughness of APH-treated surfaces were compared with those of untreated (UT) and anodized and heat-treated (AH) samples. For in vivo tests, 32 miniscrews (16 UT and 16 APH) were inserted into 16 Wistar rats, one UT and one APH-treated miniscrew in either tibia. The miniscrews were extracted after 3 and 6 weeks and their osseointegration (n = 8 for each time point and group) was investigated by surface and histological analyses and removal torque measurements. Results: APH treatment formed a dense surface array of nanotubular TiO2 layer covered with a compact apatite-like film. APH-treated samples showed better bioactivity and biocompatibility compared with UT and AH samples. In vivo, APH-treated miniscrews showed higher removal torque and bone-to-implant contact than did UT miniscrews, after both 3 and 6 weeks (p < 0.05). Also, early deposition of densely mineralized bone around APH-treated miniscrews was observed, implying good bonding to the treated surface. Conclusions: APH treatment enhanced the bioactivity, and the biomechanical and bone regenerative properties of the Ti6Al4V alloy miniscrews. The enhanced initial stability afforded should be valuable in orthodontic applications.