• Title, Summary, Keyword: SiHa

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Microstructure and Biocompatibility of Ti-Nb-Si-HA Composites Fabricated by Rapid Sintering Using HEMM Powders

  • Woo, Kee-Do;Kim, Sang-Hyuk;Kang, Dong-Soo;Kim, Dong-Gun
    • Korean Journal of Materials Research
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    • v.23 no.7
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    • pp.353-358
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    • 2013
  • To improve coating ability and the life of the coating, Ti based composite materials with hydroxyapatite(HA) should be developed. The raw materials of Ti-26wt%, Nb-1wt%, and Si with 10wt% HA were mixed for 24 h by a mixing machine and milled for 1 h to 6 h by planetary mechanical ball milling. Ti-26%Nb-1%Si-(10%HA) composites, composed of nontoxic elements, were fabricated successfully by spark plasma sintering(SPS) at $1000^{\circ}C$ under 70MPa. The relative density of the sintered Ti-Nb-Si-HA composites using the 24 h mixed powder, and the 6 h milled powder, was 91% and 97 %, respectively. The effects of HA contents and milling time on microstructure and mechanical properties were investigated by SEM and hardness tester, respectively. The Vickers hardness of the composites increased with increasing milling time and higher HA content. The Young's modulus of the sintered Ti-26%Nb-1%Si-10%HA composite using the 6 h-milled powder was 55.6 GPa, as obtained by compression test. Corrosion resistance of the Ti-26wt%Nb-1wt%Si composite was increased by milling and by the addition of 10wt%HA. Wear resistance was improved with increasing milling time. Biocompatibility of the Ti-Nb-Si alloys was improved by the addition of HA.

Aerosol Deposition and Its Potential Use for Bioactive Ceramic Coatings

  • Hahn, Byung-Dong;Park, Dong-Soo;Lee, Jeong-Min;Choi, Jong-Jin;Ryu, Jung-Ho;Yoon, Woon-Ha;Lee, Byoung-Kuk;Choi, Joon-Hwan;Kim, Hyoun-Ee
    • Proceedings of the Materials Research Society of Korea Conference
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    • pp.41.1-41.1
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    • 2009
  • Aerosol Deposition (AD) is anovel way to fabricate bioactive ceramic coatings in biomedical implants and prostheses applications. In the present work, silicon-substituted hydroxyapatite (HA) coatings on commercially pure titanium were prepared by aerosol deposition using Si-HA powders. The incorporation of silicon in the HA lattice is known to improve the bioactivity of the HA, makingsilicon-substitute HA an attractive alternative to pure HA in biomedical applications. Si-HA powders with the chemical formula $Ca_{10}(PO_4)_6-x(SiO_4)x(OH)_2-x$, having silicon contents up to x=0.5 (1.4 wt%), were synthesized by solid-state reaction of $Ca_2P_2O_7$, $CaCO_3$, and $SiO_2$. The Si-HA powders were characterized by X-ray diffraction (XRD), X-ray fluorescence spectrometry (XRF), and Fourier transform infrared spectroscopy(FT-IR). The corresponding coatings were also analyzed by XRD, scanning electron microscopy (SEM), and electron probe microanalyzer (EPMA). The results revealed that a single-phase Si-HA was obtained without any secondary phases such as $\alpha$- or $\beta$-tricalcium phosphate (TCP) for both the powders and the coatings.The Si-HA coating was about $5\;{\mu}m$ thick, had a densemicrostructure with no cracks or pores. In addition, the proliferation and alkaline phosphatase (ALP) activity of MC3T3-E1 preosteoblast cells grown on the Si-HA coatings were significantly higher than those on the bare Ti and pure HA coating. These results revealed the stimulatory effects induced by siliconsubstitution on the cellular response to the HA coating.

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Evalution of Input and Output Amount of Silica in Sandy Paddy Soil during Growing Periods of Rice Plant (벼 재배과정중 사질답에서 규소의 유, 출입량 평가)

  • Seo, Young-Jin;Kim, Jong-Su;Kim, Chang-Bae;Park, Man;Lee, Dong-Hoon;Choi, Choong-Lyeal;Choi, Jung
    • Korean Journal of Soil Science and Fertilizer
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    • v.35 no.3
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    • pp.162-168
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    • 2002
  • The silica uptake of rice plant(Oryza sativa L.) and a potential capacity of paddy soil as a source of silica supply for rice plant was studied under field experimental condition. Amount of Si from irrigation water, rainfall, which was a source of silica supply, and percolating rate of water through paddy soil profile as a source of silica loss from paddy soil, was investigated. Rice plants were grown in three different conditions, which included Control as non-fertilized, RDA's recommandation(NPK, Urea-Fused phophate-Potassium chloride=$110-45-57kg\;ha^{-1}$) and RDA's recommandation with supplement of silicate fertilizer(NPK+Si, Urea-Fused phosphate-Potassium chloride+Si=$110\;N-45\;P_2O_5-57\;K_2O+267.2\;Si\;kg\;ha^{-1}$). An amount of silica supply from rainfall was $0.5kg\;ha^{-1}$ and average amount of silica supplied from irrigation water $42.5kg\;ha^{-1}$, ranging from $28.1kg\;ha^{-1}$ to $58.8kg\;ha^{-1}$. Silica amount percolated through the soil profile have uniform trend comparatively showing $62.9kg\;ha^{-1}$ in Control, $64.8kg\;ha^{-1}$ in NPK treatment and $62.9kg\;ha^{-1}$ in NPK+Si treatment. Silica uptaked by Rice plant was $335.6kg\;ha^{-1}$ in Control, $406.6kg\;ha^{-1}$ in NPK+Si treatment and $471.1kg\;ha^{-1}$ in NPK+Si treatment. The difference between an amount of Si input(from rainfall, irrigation water and silicate fertilizer) and an amount of Si output(percolated Si in soil, uptaked Si by rice plant) was $357.4kg\;ha^{-1}$ in control, $412.1kg\;ha^{-1}$ in NPK treatment and $238.2kg\;ha^{-1}$ in NPK+Si treatment. Results of our study imply that paddy soil is a potential pool as a source of Si supply during growing periods of rice plant.

Effect of EB-PVD Coated Si/HA Film Thickness on Surface Characteristics of Ti-35Nb-10Zr Alloy

  • Jeong, Yong-Hoon;Eun, Sang-Won;Choe, Han-Cheol
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • pp.213-213
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    • 2012
  • In this study, effect of EB-PVD coated Si/HA film thickness on surface characteristics of Ti-35Nb-10Zr alloy was investigated. The Ti-35Nb-10Zr alloy was fabricated by arc melting method. The Si/HA layers were coated with 0.8 wt.% of Si in pure HA by EB-PVD method. The coating thickness was consisted with 100 - 300 nm for each group, the surface characteristics was analyzed by FE-SEM, EDS, XRD, XRF and corrosion test. The Si/HA coating layer was well deposited on the alloy surface by EB-PVD, the thickness was correlative factor with HA peaks and corrosion resistance value.

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Reversal of Resistance towards Cisplatin by Curcumin in Cervical Cancer Cells

  • Roy, Madhumita;Mukherjee, Sutapa
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.3
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    • pp.1403-1410
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    • 2014
  • Epigenetic regulators like histone deacetylases (1 and 2), and viral onco-proteins (E6/E7) are known to be overexpressed in cervical cancer cells. The present study was designed to investigate the effect of curcumin on HDACs (1 and 2) and HPV E6/E7 in the cervical cancer cell line SiHa and a drug resistant clone $SiHa^R$ (derived from SiHa). It was further intended to investigate whether curcumin could sensitize the cells towards cisplatin induced cell killing by modulation of multi drug resistant proteins like MRP1 and Pgp1. Curcumin inhibited HDACs, HPV expression and differentially increased acetylation and up-regulation of p53 in SiHa and $SiHa^R$, leading to cell cycle arrest at G1-S phase. Up-regulation of pRb, p21, p27 and corresponding inhibition of cyclin D1 and CDK4 were observed. Cisplatin resistance in $SiHa^R$ due to over-expression of MRP1 and Pgp1 was overcome by curcumin. Curcumin also sensitized both the cervical cancer cells towards cisplatin induced cell killing. Inhibition of HDACs and HPVs led to cell cycle arrest at G1/S phase by alteration of cell cycle regulatory proteins. Suppression of MRP1 and Pgp1 by curcumin resulted in sensitization of cervical cancer cells, lowering the chemotherapeutic dose of the drug cisplatin.

Aquaporin 8 Involvement in Human Cervical Cancer SiHa Migration via the EGFR-Erk1/2 Pathway

  • Shi, Yong-Hua;Tuokan, Talaf;Lin, Chen;Chang, Heng
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.15
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    • pp.6391-6395
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    • 2014
  • Overexpression of aquaporins (AQPs) has been reported in several human cancers. Epidermal growth factor receptor (EGFR)-extracellular signal-regulated kinases 1/2 (Erk1/2) are associated with tumorigenesis and cancer progression and may upregulate AQP expression. In this study, we demonstrated that EGF (epidermal growth factor) induces SiHa cells migration and AQP8 expression. Wound healing results showed that cell migration was increased by 2.79-1.50-fold at 24h and 48h after EGF treatment. AQP8 expression was significantly increased (3.33-fold) at 48h after EGF treatment in SiHa cells. An EGFR kinase inhibitor, PD153035, blocked EGF-induced AQP8 expression and cell migration and AQP8 expression was decreased from 1.59-fold (EGF-treated) to 0.43-fold (PD153035-treated) in SiHa. Furthermore, the MEK (MAPK (mitogen-activated protein kinase)/Erk (extracellular signal regulated kinase)/Erk inhibitor U0126 also inhibited EGF-induced AQP8 expression and cell migration. AQP8 expression was decreased from 1.21-fold (EGF-treated) to 0.43-fold (U0126-treated). Immunofluorescence microscopy further confirmed the results. Collectively, our findings show that EGF induces AQP8 expression and cell migration in human cervical cancer SiHa cells via the EGFR/Erk1/2 signal transduction pathway.

Inhibition of Cervical Cancer Cell Growth by Gene Silencing of HPV16 E6 Induced by Short-interfering RNA

  • Park, Sang-Muk;Lee, Sun-Kyung;Kim, Yoon-Sik
    • Korean Journal of Clinical Laboratory Science
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    • v.43 no.3
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    • pp.89-97
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    • 2011
  • The Human Papilloma Virus (HPV) infection has been strongly associated with pathogenesis of uterine cervix carcinoma. HPV type 16, a causative agent of uterine cervix carcinoma, encodes the E6 and E7 oncogenes, expression of which is pivotal for malignant transformation and maintenance of malignant phenotypes. To develop a gene therapy for HPV-related carcinoma, We investigated the effect of E6 short-interfering RNA (E6 siRNA) on the expression of this oncogene and on the growth of HPV 16-related uterine cervix carcinoma cells. SiHa cells, a uterine cervix carcinoma cell line, which contain a single copy of HPV 16 integrated in the chromosome and express the E6 and E7 oncogenes. Before 24 hr of transfection, cells were seeded and transfected with control plasmid or E6 siRNA-expressing plasmid. The mRNA was analysed by reverse transcriptase polymerase chain reaction (RT-PCR). The cell growth rate was investigated by MTT method. The E6 mRNA level in SiHa cells was decreased in HPV 16 E6 siRNA-expression vector transfected cells and a decrease in the growth of these cells was also observed. From these results. it is evident that E6 siRNA played a role in suppression of growth of SiHa cells and has a fair chance as a candidate for gene specific therapy for HPV related uterine cervix carcinoma.

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A Study on Improvement and Degradation of Si/SiO2 Interface Property for Gate Oxide with TiN Metal Gate

  • Lee, Byung-Hyun;Kim, Yong-Il;Kim, Bong-Soo;Woo, Dong-Soo;Park, Yong-Jik;Park, Dong-Gun;Lee, Si-Hyung;Rho, Yong-Han
    • Transactions on Electrical and Electronic Materials
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    • v.9 no.1
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    • pp.6-11
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    • 2008
  • In this study, we investigated effects of hydrogen annealing (HA) and plasma nitridation (PN) applied in order to improve $Si/SiO_2$ interface characteristics of TiN metal gate. In result, HA and PN showed a positive effect decreasing number of interface state $(N_{it})$ respectively. After FN stress for verifying reliability, however, we identified rapid increase of $N_{it}$ for TiN gate with HA, which is attributed to hydrogen related to a change of $Si/SiO_2$ interface characteristic. In contrast to HA, PN showed an improved Nit and gate oxide leakage characteristic due to several possible effects, such as blocking of Chlorine (Cl) diffusion and prevention of thermal reaction between TiN and $SiO_2$.

A Suitability Selection for Marine Afforestation with Physical Environments (바다숲 조성해역의 물리적 환경을 고려한 최적 적지선정)

  • Oh, Tae-Geon;Kim, Dae-Kweon;Kim, Chang-Gil;Lee, Moon-Ock;Cho, Jae-Kweon
    • Journal of the Korean Society of Marine Engineering
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    • v.34 no.1
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    • pp.183-194
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    • 2010
  • A suitability analysis for marine afforestation was carried out on physical items based on slop rate, bottom sediment, light intensity, velocity, and wave at north Geomoon waters in Korea. The data from each physical item were changed to a GSDM (Gridded Spatial Distribution Map) using Kriging interpolation. A GSDM grid includes information, and each grid was given a SI (suitability index) of 3 grades(SI of first suitability was 100, SI of second suitability was 50, and non-suitability had no SI). According to the analysis results of all overlaid GSDM, first suitability had 500 SI, and suitability area was 0.25ha. Second and third suitability had 400~450 SI, and suitability area was 2.36ha, 1.80ha, respectively. Therefore, the results suggest that reefs installed for marine afforestation should be anti-slip types against steep slope, and the target species need to include algae with low compensation light intensity in second and third suitability.

Antitumor Effects of Camptothecin Combined with Conventional Anticancer Drugs on the Cervical and Uterine Squamous Cell Carcinoma Cell Line SiHa

  • Ha, Sang-Won;Kim, Yun-Jeong;Kim, Won-Yong;Lee, Chung-Soo
    • The Korean Journal of Physiology and Pharmacology
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    • v.13 no.2
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    • pp.115-121
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    • 2009
  • Functional defects in mitochondria are involved in the induction of cell death in cancer cells. We assessed the toxic effect of camptothecin against the human cervical and uterine tumor cell line SiHa with respect to the mitochondria-mediated cell death process, and examined the combined effect of camptothecin and anticancer drugs. Camptothecin caused apoptosis in SiHa cells by inducing mitochondrial membrane permeability changes that lead to the loss of mitochondrial membrane potential, decreased Bcl-2 levels, cytochrome c release, caspase-3 activation, formation of reactive oxygen species and depletion of GSH. Combination of camptothecin with other anticancer drugs (carboplatin, paclitaxel, doxorubicin and mitomycin c) or signaling inhibitors (farnesyltransferase inhibitor and ERK inhibitor) did not enhance the camptothecin-induced cell death and caspase-3 activation. These results suggest that camptothecin may cause cell death in SiHa cells by inducing changes in mitochondrial membrane permeability, which leads to cytochrome c release and activation of caspase-3. This effect is also associated with increased formation of reactive oxygen species and depletion of GSH. Combination with other anticancer drugs (or signaling inhibitors) does not appear to increase the anti-tumor effect of camptothecin against SiHa cells, but rather may reduce it. Combination of camptothecin with other anticancer drugs does not seem to provide a benefit in the treatment of cervical and uterine cancer compared with camptothecin monotherapy.