• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.52.1-52.1
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• 2011

In this work, the effect of the addition of bioactive glass in the biocompatibility and mechanical behavior of conventional TTCP/DCPA based bone cement were investigated. The cement was initially modified with chitosan and HPMC which cross-linked with citric acid to improved mechanical properties.The injectable bone substitutes were further modified by adding varying amounts of bioactive glass (0%, 10%, 20% and 30%) and its effects on the biocompatibility of the material were studied. Afterbio-glass powders were mixed with the optimized composition for HPMC and citric acid content,the IBS was incubated at $37^{\circ}C$ at different time intervals and showed progressive formation of HAp with increasing time. Mechanical properties like Vickers hardness and compressive strength were found to increase with the increasing amount of bioactive glass addition and that setting time was shortened. The fabricated IBS morphologies were further characterized using SEM. MTT assay was performed to check the cell cytotoxicity and cell proliferation for 1, 3 and 5 days. Cell morphology, adhesion and proliferation behavior of cell in the IBS by culturing MG-63 cells on the IBS for 20, 60 and 90 mins and 1, 3 and 5 days was also investigated. All the results showed increasing biocompatibility as the bioglass content increased. MTT results found the materials to be cytocompatible and SEM images showed that cells attached and proliferated successfully.

• Journal of Technologic Dentistry
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• v.36 no.3
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• pp.179-184
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• 2014

Purpose: This study was performed to investigate the release behavior of bioactive materials as a BMP-2 embedding on the porous titanium implant. Methods: Porous Ti implant samples were fabricated by sintering of spherical Ti powders in a high vacuum furnace. Specimens diameter and height were 4mm and 10mm. Embedding materials were used to stamp ink. Sectional images, porosity and release behavior of porous Ti implants were evaluated by scanning electron microscope(SEM), mercury porosimeter and UV-Vis-NIR spectrophotometer. Results: Internal pore structure was formed fully open pore. Average pore size and porosity were $8.993{\mu}m$ and 8.918%. Embedding materials were released continually and slowly. Conclusion: Porous Ti implant was fabricated successfully by sintering method. Particles are necking strongly each other and others portions were vacancy. Therefore bioactive materials will be able to embedding to porous Ti implants. If the development of the fusion implant of the bioactive material will be able to have the chance to several patients.

• Bulletin of the Korean Chemical Society
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• v.35 no.7
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• pp.1979-1984
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• 2014

We have developed an efficient method to generate highly active Pd and PdO nanoparticles (NPs) dispersed on graphene and graphene oxide (GO) by an impregnation method combined with thermal treatments in $H_2$ and $O_2$ gas flows, respectively. The Pd NPs supported on graphene (Pd/G) and the PdO NPs supported on GO (PdO/GO) demonstrated excellent carbon-carbon cross-coupling reactions under a solvent-free, environmentally-friendly condition. The morphological and chemical structures of PdO/GO and Pd/G were fully characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). We found that the remarkable reactivity of the Pd/G and PdO/GO catalysts toward the cross-coupling reaction is attributed to the high degree of dispersion of the Pd and PdO NPs while the oxidative states of Pd and the oxygen functionalities of graphene oxide are not critical for their catalytic performance.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.3
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• pp.315-319
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• 2003

Bioactive organosulfur phytochemicals were isolated from fresh broccoli using methlylene chloride as an extract solvent and identified by GC/MSD analyses. Major organosulfur phytochemicals of broccoli extract were found to be isothiocyanates, which constitute 40.42% of total phytochemicals. The isothiocyanates from broccoli extract were identified to be 3-butenyl, 4-methyl thiobutyl, 4-methylthio-3-butenyl, 5-methylthiopentyl, 2-phenylethyl, 3-methyl sulfinyl propyl, and 4-methylsulfinylbutyl isothiocyanates, of which major isothio cyanates were 3 butenyl isothiocyanate and 4-methylsulfinylbutyl isothiocyanate, constituting about 38.55% of total isothiocyanates present in the solvent extract. Also, nitrites, corresponding to products from enzymatic hydrolysis of glucosinolates were identified as 4-methylthiobutyl, 5-methyl thiopentyl, 2-phenylethyl and 4-methylsulfinylbutyl nitrile. In addition, three sulfides were identified as dimethyl disulfide, dimethyl trisulfide and dimethyl tetrasulfide.

• Journal of Physiology & Pathology in Korean Medicine
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• v.18 no.1
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• pp.260-264
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• 2004

The effects of bioactive fractions from Brachyglottis monroi on biological activity were investigated. this bioactive subfraction 6-5 is the most cytotoxic to P388 murine leukaemia cell lines. A comparison of IC/sub 50/ values of these subfraction in cancer cell lines showed that their susceptibility to these subfractions decreased in the following order; Fr. 6-5 > Fr. 6-3 > Fr. 6-6 > Fr. 6-1 > Fr. 6-2 > Fr. 6-4 by the MTT method. Silica gel flash column chromatography concentrated the cytotoxic activity in subfraction 6-5 which eluted with 30% and 40% ethyl acetate : hexane gave a major bioactive (51 mg, P388 IC/sub 50/ 8,286 ng/mL at 7.5 ㎍/disc).

• Bulletin of the Korean Chemical Society
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• v.31 no.11
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• pp.3123-3127
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• 2010

A highly sensitive electrochemical detection method for dopamine (DA) has been developed by relying on a multiwalled carbon nanotube (CNT)-sol-gel titania-Nafion composite film modified glassy carbon (GC) electrode. The CNT-titania-Nafion/GC electrode exhibited excellent electrocatalytic activity towards DA. Therefore, the CNT-titania-Nafion/GC electrode showed improved voltammetric and amperometric responses for DA compared to those obtained with both titania-Nafion/GC and Nafion/GC electrodes. The CNT-titania-Nafion/GC electrode gave a linear response ($R^2$ = 0.999) for DA from $0.5\;{\mu}M$ to 0.5 mM with a detection limit (S/N = 3) of $0.1\;{\mu}M$ and a good sensitivity of 150 mA/M while other electrodes such as CNT-Nafion/GC, titania-Nafion/GC, and a bare GC gave a sensitivity of 89, 39, and 36 mA/M, respectively. Besides, the CNT-titania-Nafion/GC electrode displayed very fast response time within 2 s. The modified electrode showed good selectivity against ascorbic acid. The modified electrode showed good stability and reproducibility. The CNT-titania-Nafion/GC electrode was applied to the determination of DA in urine and serum samples.

• Archives of Pharmacal Research
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• v.24 no.4
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• pp.270-275
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• 2001

Bioisostere approach has been shown to be useful to augment potency or to modify certain physiological properties of a lead compound. Based upon well documented bioisosterism, an isosteric replacement of benzene ring of 4-hydroxy-2-quinolone compound (L-695902) with a thiophene moiety was carried out to prepare the title compounds, 4-hydroxy-6-oxo-6,7-dihydro-thieno[2,3-b] pyrimidines 15. The resulting bioisosteric compounds 15 were evaluated for their antagonistic activity (birding assay) for NMDA receptor glycine site.

• Molecules and Cells
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• v.39 no.6
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• pp.484-494
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• 2016

Plant cells have a remarkable ability to induce pluripotent cell masses and regenerate whole plant organs under the appropriate culture conditions. Although the in vitro regeneration system is widely applied to manipulate agronomic traits, an understanding of the molecular mechanisms underlying callus formation is starting to emerge. Here, we performed genome-wide transcriptome profiling of wild-type leaves and leaf explant-derived calli for comparison and identified 10,405 differentially expressed genes (> two-fold change). In addition to the well-defined signaling pathways involved in callus formation, we uncovered additional biological processes that may contribute to robust cellular dedifferentiation. Particular emphasis is placed on molecular components involved in leaf development, circadian clock, stress and hormone signaling, carbohydrate metabolism, and chromatin organization. Genetic and pharmacological analyses further supported that homeostasis of clock activity and stress signaling is crucial for proper callus induction. In addition, gibberellic acid (GA) and brassinosteroid (BR) signaling also participates in intricate cellular reprogramming. Collectively, our findings indicate that multiple signaling pathways are intertwined to allow reversible transition of cellular differentiation and dedifferentiation.

• Journal of the Korean Ceramic Society
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• v.40 no.3
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• pp.255-261
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• 2003

Alumina glazed with a bioactive glass reacted in Simulated Body Fluids(SBF) to investigate the behavior of hydroxyapatite formation on the glass coat layer. Various crystalline phases were found depending on the firing temperatures when the bioactive glass coat was heat-treated. The glass coat was crystallized into ${\beta}$-wollastonite and apatite when fired at 1100$^{\circ}C$, and ${\alpha}$-wollastonite and apatite when fired at 1200$^{\circ}C$. Those samples reacted in SBF, and it is observed that hydroxyapatite developed on the surface of the crystallized glaze. Its formation was much easier in the sample with ${\alpha}$-wollastonite than with ${\beta}$-wollastonite. This is because that the ${\alpha}$-wollastonite dissolves more easily than ${\beta}$-wollastonite does in SBF.

• Toxicological Research
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• v.14 no.4
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• pp.541-545
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• 1998

This experiment carried out to compare the protective effects of some antioxidants to hydroxyl radicals in embryonic mouse whole brain tissue culture. The ICR mouse whole brain (13 embryonic day) was cultured in hydroxyl radical system in which radicals were generated by 20 mU / ml glucose oxidase (GO). In this experiment, to make ferrous iron from ferric iron, iron as an accelerator, and ascorbic acid as a reductant were used. For comparison of the protective effects to hydroxyl radicals, antioxidants such as desferrioxamine (DFX), laccase. water or ethanol extracts from Rhus Vemiciflua Stokes (RVS), and $\alpha$-tocopherol were used, because they relate to metal ion. The results of this experiment showed that all antioxidants protected effectively the cytotoxicity from hydroxyl radicals in the brain cultures. More than 70% of cell viabilities among different antioxidants was at 1 mM DFX, 1.43 $\mu\textrm{m}$ laccase, 12.5 $\mu\textrm{m}$ water extract, 12.5 $\mu\textrm{m}$ ethanol extract and 50 $\mu\textrm{m}$ $\alpha$-tocopherol individually, compared with 20 mU/ml GO alone. In comparison to the antioxidative activities of antioxidants, laccase and extracts from RVS showed strong antioxidative effects even at low concentration.