RESUMO
Cellulose and one dimensional nano-material composite has been investigated for various industrial applications due to their optical, mechanical and electrical properties. In present investigation, cellulose/silica and silica-gold hybrid biomaterials were prepared by sol-gel covalent cross-linking process. The tetraethoxysiliane (TEOS) and gold precursors and γ-aminopropyltriethoxysilane (γ-APTES) as coupling agent were used for sol-gel cross-linking process. The chemical and morphological properties of cellulose/silica and cellulose/silica-gold nano-materials via covalent cross-linking hybrids were confirmed by FTIR, XRD, SEM, and TEM analysis. In the sol-gel process, the inorganic particles were dispersed in the cellulose host matrix at the nanometer scale, bonding to the cellulose through the covalent bonds.
Assuntos
Materiais Biocompatíveis/química , Celulose/química , Eletrônica , Ouro/química , Nanoestruturas/química , Dióxido de Silício/química , Fenômenos Mecânicos , Fenômenos Ópticos , Propilaminas , Silanos/química , TemperaturaRESUMO
In eukaryotes, the activation of the prereplicative complex and assembly of an active DNA unwinding complex are critical but poorly understood steps required for the initiation of DNA replication. In this report, we have used bimolecular fluorescence complementation assays in HeLa cells to examine the interactions between Cdc45, Mcm2-7, and the GINS complex (collectively called the CMG complex), which seem to play a key role in the formation and progression of replication forks. Interactions between the CMG components were observed only after the G(1)/S transition of the cell cycle and were abolished by treatment of cells with either a CDK inhibitor or siRNA against the Cdc7 kinase. Stable association of CMG required all three components of the CMG complex as well as RecQL4, Ctf4/And-1, and Mcm10. Surprisingly, depletion of TopBP1, a homologue of Dpb11 that plays an essential role in the chromatin loading of Cdc45 and GINS in yeast cells, did not significantly affect CMG complex formation. These results suggest that the proteins involved in the assembly of initiation complexes in human cells may differ somewhat from those in yeast systems.
Assuntos
Proteínas de Ciclo Celular/química , Proteínas de Ciclo Celular/metabolismo , Proteínas de Ligação a DNA/química , Proteínas de Ligação a DNA/metabolismo , Proteínas Nucleares/química , Proteínas Nucleares/metabolismo , RecQ Helicases/química , RecQ Helicases/metabolismo , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Proteínas de Transporte/metabolismo , Ciclo Celular , Proteínas de Ciclo Celular/genética , Proteínas Cromossômicas não Histona/química , Proteínas Cromossômicas não Histona/genética , Proteínas Cromossômicas não Histona/metabolismo , Quinases Ciclina-Dependentes/metabolismo , Proteínas de Ligação a DNA/genética , Células HeLa , Humanos , Proteínas Luminescentes/química , Proteínas Luminescentes/genética , Proteínas Luminescentes/metabolismo , Componente 2 do Complexo de Manutenção de Minicromossomo , Componente 7 do Complexo de Manutenção de Minicromossomo , Proteínas de Manutenção de Minicromossomo , Complexos Multiproteicos , Proteínas Nucleares/genética , Proteínas Serina-Treonina Quinases/metabolismo , RecQ Helicases/genética , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismoRESUMO
We studied Al2O3-doped ZnO (AZO) thin film as a transparent conducting layer for photovoltaic cell operated in wide range of solar spectrum. Effects of substrate temperature on the optical, structural, and electrical properties of thin AZO film were investigated. AZO films were deposited on glass substrates by RF magnetron sputtering system using a 2 wt.% Al2O3 doped target at different temperature conditions. The grown AZO films at low deposition temperatures ranged from 100 degrees C to 300 degrees C show relatively low resistivity, while the samples deposited at 400 degrees C or room temperature are with higher resistivity of -8 x 10(-4) Ω x cm. The measurement by atomic force microscopy reveals that all AZO films possess very smooth surface morphologies with RMS values below 1 nm regardless of substrate temperature. Optical transmittance of the AZO films increases from 81% to 95% as the substrate temperature increases. The AZO films deposited at 200 degrees C condition shows the optimum value of figure-of-merit of 43.7 x 10(-3) Ω(-1), showing the resistivity of 3.4 x 10(-4) Ω x cm and the transmittance of 94%. Additionally, it is noted that the transmittance of the films at near infrared wavelength of 1250 nm exceeds 90%, demonstrating the feasibility as a transparent electrode for thin film solar cell with narrow band gap.