Corrosion protection of stainless steel by polysiloxane hybrid coatings prepared using the sol-gel process

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Characterization of nanosized ZnAl2O4 spinel synthesized by the sol-gel method

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Thermo-reversible sol-gel transition of TiO2 nanoparticles with surface modified by p-toluene sulfonic acid

In this paper an unprecedent thermo-reversible sol-gel transition for titania nanoparticles dispersed in a solution of p-toluene sulfonic acid (PTSH) in isopropanol is reported. The sol formed by the thermo-hydrolysis at 60 degrees C of titanium tetraisopropoxide (Ti((OPr)-Pr-i)(4)) reversibly changes into a turbid gel upon cooling to room temperature. Turbidimetric measurements performed for samples containing different nominal acidity ratios (A = [PTSH]/[Ti]) have evidenced that the gel transformation temperature increases from 20 to 35 degrees C as the [PTSH]/[Ti] ratio increases from 0.2 to 2.0. SAXS results indicate that the thermo-reversible gelation is associated to a reversible aggregation of a monodisperse set of titania nanoparticles with average gyration radius of approximate to 2 nm. From the different PTSH species evidenced by Raman spectroscopy and TG/DTA of dried gels we proposed that the then-no-reversible gelation in this systems is induced by the formation of a supramolecular network, in which the protonated surface of nanoparticles is interconnected through cooperative hydrogen bonds between -SO3 groups of p-toluene sulfonic acid. (C) 2009 Elsevier Ltd. All rights reserved.

Zirconia foams prepared by integration of the sol-gel method and dual soft template techniques

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Use of Saccharomyces cerevisiae immobilized in agarose gel as a binding agent for diffusive gradients in thin films

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Characterization of Staphylococcus aureus isolates in milk and the milking environment from small-scale dairy farms of São Paulo, Brazil, using pulsed-field gel electrophoresis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Sol-gel synthesis of mesoporous CaCu3Ti4O12 thin films and their gas sensing response

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Use of Pyrosequencing and Denaturing Gradient Gel Electrophoresis to Examine the Effects of Probiotics and Essential Oil Blends on Digestive Microflora in Broilers Under Mixed Eimeria Infection

A protective digestive microflora helps prevent and reduce broiler infection and colonization by enteropathogens. In the current experiment, broilers fed diets supplemented with probiotics and essential oil (EO) blends were infected with a standard mixed Eimeria spp. to determine effects of performance enhancers on ileal and cecal microbial communities (MCs). Eight treatment groups included four controls (uninfected-unmedicated [UU], unmedicated-infected, the antibiotic BMD plus the ionophore Coban as positive control, and the ionophore as negative control), and four treatments (probiotics BC-30 and Calsporin; and EO, Crina Poultry Plus, and Crina PoultryAF). Day-old broilers were raised to 14 days in floor pens on used litter and then were moved to Petersime batteries and inoculated at 15 days with mixed Eimeria spp. Ileal and cecal samples were collected at 14 days and 7 days postinfection. Digesta DNA was subjected to pyrosequencing for sequencing of individual cecal bacteria and denaturing gradient gel electrophoresis (DGGE) for determination of changes in ileal and cecal MC according to percentage similarity coefficient (%SC). Pyrosequencing is very sensitive detecting shifts in individual bacterial sequences, whereas DGGE is able to detect gross shifts in entire MC. These combined techniques offer versatility toward identifying feed additive and mild Eimeria infection modulation of broiler MC. Pyrosequencing detected 147 bacterial species sequences. Additionally, pyrosequencing revealed the presence of relatively low levels of the potential human enteropathogens Campylobacter sp. and four Shigella spp. as well as the potential poultry pathogen Clostridiun perfringens. Pre- and postinfection changes in ileal (56%SC) and cecal (78.5%SC) DGGE profiles resulted from the coccidia infection and with increased broiler age. Probiotics and EO changed MC from those seen in UU ilea and ceca. Results potentially reflect the performance enhancement above expectations in comparison to broilers not given the probiotics or the specific EO blends as feed supplements.

Small angle X-ray scattering study of structural changes in silica gel modified with organofunctional groups

Silica gel surfaces, organofunctionalized with 2-mercaptobenzimidazole, iminosalicylaldehyde and imidazole groups were examined using the small angle X-ray scattering technique (SAXS). From the scattering intensity data it was concluded that particles have a uniform size after the coupling reaction. The chemical treatment of the silica gel leads to an attachment of the organofunctional groups on the solid-pore interface of the silica with an increase of the mean size of the solid phase and some coalescence of the pores. © 1989.

Adsorption of Cu(II), Zn(II), Cd(II), Hg(II) and Pb(II) from aqueous solutions on a 2-mercaptobenzimidazole-modified silica gel

The chemically modified silica, obtained by reacting 2-mercaptobenz-imidazole with 3-chloropropyl silica gel, was used to adsorb Cu(II), Zn(II), Cd(II) and Pb(II) from aqueous solutions at various pH. Between pH 3-5, the order of selectivity was Hg(II) > Cd(II) ≫ Cu(II) ∼ Zn(II) ∼ Pb(II). Under batch conditions retentions of 100% were achieved for all metals except for Pb(II) where 93% was attained. Under column conditions recoveries of 100% were obtained for all metals. © 1990 Springer-Verlag.

Structural characterization of a tin oxyhydroxide gel and its precursor sol

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Pore size distribution of unsupported SnO2 membranes prepared by sol-gel process - Code: EP21

Unsupported SnO2 membranes were prepared by sol-gel process and characterized by N2 adsorption-desorption isotherms and X-ray diffraction. Results show that the texture of dried samples does not change appreciably with the concentration of electrolyte. All of the pore size range used in ultrafiltration process was screened using sintering temperature between 300 and 700°C. © 1994 Kluwer Academic Publishers.

Morphological characterization of aqueous tin oxyhydroxide gel

Light scattering, electron microscopy and X-ray diffraction are used to determine the morphology and size of particles in diluted aqueous gel of tin (IV) oxyhydroxide. Data show that the gel is composed of spherical 2-3 nm sized crystalline particles aggregated as rigid branched chains. It is suggested that stiffness of chains results from dissolution-precipitation equilibria and chemical bonding between particles within the chains. © 1994.

Evolution of the fractal structure during sintering of SnO2 compacted sol-gel powder

The structural evolution during sintering of compacted SnO2 sol-gel powder was investigated using nitrogen adsorption isotherm analysis. Results show that for sintering temperatures up to 400°C the samples have a fractal pore size distribution. As the sintering temperature increases, a structural rearragement occurs, allowing an increase of the efficiency of particle packing and the reduction of fractality. Above 400°C, the pore size growth associated with grain coalescence is the main structural change observed as the sintering temperature increases. © 1995.