39 research outputs found
Formation of a novel polypyrrole porous phosphate glass ceramic nanocomposite
This work is concerned with evidences of a new composite system, formed by in situ polimerization of pyrrole moieties in the copper-exchanged pore surface of LiTi2(PO4)(3) glass ceramic.10216716
Thermal properties of metal-metal bonded Pd(I) complexes supported onto porous Vycor glass
Long-term (trophic) purinergic signalling: purinoceptors control cell proliferation, differentiation and death
The purinergic signalling system, which uses purines and pyrimidines as chemical transmitters, and purinoceptors as effectors, is deeply rooted in evolution and development and is a pivotal factor in cell communication. The ATP and its derivatives function as a 'danger signal' in the most primitive forms of life. Purinoceptors are extraordinarily widely distributed in all cell types and tissues and they are involved in the regulation of an even more extraordinary number of biological processes. In addition to fast purinergic signalling in neurotransmission, neuromodulation and secretion, there is long-term (trophic) purinergic signalling involving cell proliferation, differentiation, motility and death in the development and regeneration of most systems of the body. In this article, we focus on the latter in the immune/defence system, in stratified epithelia in visceral organs and skin, embryological development, bone formation and resorption, as well as in cancer. Cell Death and Disease (2010) 1, e9; doi:10.1038/cddis.2009.11; published online 14 January 201
A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)
Meeting abstrac
Optical sensor for sulfur dioxide determination in wines
A method for the determination of free and total sulfur dioxide in wines, based on the use of an optical sensor that employs a dichlorobis( diphenylphosphino) methane dipalladium I complex [Pd-2(dppm)(2)Cl-2] immobilized in a PVC membrane plasticized with o-nitrophenyloctylether (o-NPOE) is described. A sensing membrane [4.2% Pd-2(dppm)(2)Cl-2, 20.8% PVC, and 75% o-NPOE] was adapted to the tip of a bifurcated optical fiber bundle to perform reflectance measurements at 550 nm. The detection system consisted of two cells (40 mL), which hold the sample solution (plus reagents) and the optical sensor, respectively. For the determination of free SO2, a wine sample was mixed with H2SO4 solution in the sample cell, into which N-2 was bubbled, providing mixing of the solutions and conducting the SO2 formed toward the detection cell. For determination of total SO2, a KOH solution was mixed with the wine in the sample cell. Afterward, an H2SO4 solution was added to the cell, and then N-2 was bubbled to conclude the measurement. Linear responses up to 50 and 150 mg L-1 were obtained for free and total SO2, with detection limits of 0.37 and 0.70 mg L-1, respectively. The repeatability of the method was evaluated by carrying out 10 measurements using a single wine sample, providing relative standard deviation values of 2.2 and 2.5% for free and total SO2, respectively. The sensing membrane prepared from 10 mu L of the cocktail solution lasted for 80 measurements, whereas those prepared from 200 mu L can be used for 250 measurements. The method was applied to free and total SO2 determination in wines, and the results did not show significant difference from those obtained with the Ripper reference method at a confidence level of 95%.54238697870
Structural and theoretical-experimental physicochemical study of trimethoprim/randomly methylated-beta-cyclodextrin binary system
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Here we report the structural characterization, physicochemical study and molecular modeling of the inclusion complex of trimethoprim in randomly methylated beta-cyclodextrin. The phase-solubility diagram obtained at pH 7.0 exhibited a linear behavior for the RAMEB concentrations studied suggesting a 1:1 stoichiometry and absence of aggregation in solution. From stoichiometric determination by the continuous variation method we confirmed a 1:1 stoichiometry. To make a detailed characterization of the inclusion mode, spectroscopic measurements by infrared and 1D and 20 (1)H NMR spectroscopy provided evidence that the inclusion mode is characterized by inclusion of the trimethoxyphenyl ring in the cavity; interactions with methyl groups located in the border of the cavity were also detected. The structure proposed was also confirmed by semiempirical molecular modeling. (C) 2011 Elsevier Ltd. All rights reserved.3461727462751FinepCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FapitecCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq
Relation between acute and long-term cognitive decline after surgery: Influence of metabolic syndrome.
IntroductionThe relationship between persistent postoperative cognitive decline and the more common acute variety remains unknown; using data acquired in preclinical studies of postoperative cognitive decline we attempted to characterize this relationship.MethodsLow capacity runner (LCR) rats, which have all the features of the metabolic syndrome, were compared postoperatively with high capacity runner (HCR) rats for memory, assessed by trace fear conditioning (TFC) on the 7th postoperative day, and learning and memory (probe trial [PT]) assessed by the Morris water-maze (MWM) at 3 months postoperatively. Rate of learning (AL) data from the MWM test, were estimated by non-linear mixed effects modeling. The individual rat's TFC result at postoperative day (POD) 7 was correlated with its AL and PT from the MWM data sets at postoperative day POD 90.ResultsA single exponential decay model best described AL in the MWM with LCR and surgery (LCR-SURG) being the only significant covariates; first order AL rate constant was 0.07 s(-1) in LCR-SURG and 0.16s(-1) in the remaining groups (p<0.05). TFC was significantly correlated with both AL (R=0.74; p<0.0001) and PT (R=0.49; p<0.01).ConclusionSeverity of memory decline at 1 week after surgery presaged long-lasting deteriorations in learning and memory
One-step preparation of CdS nanocrystals supported on thiolated silica-gel matrix and evaluation of photocatalytic performance
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Here we report the use of a thiol-functionalized silica-gel to prepare supported CdS nanocrystals by a facile one-step procedure. Upon changing the relative proportion of the matrix we obtained nanocrystals with different average sizes and size distributions, as evidenced by spectroscopic measurements as well as TEM images. Photoluminescence spectra also indicated that the main effect of the matrix is related to the size control since the spectral profiles were found to be strongly dependent on the excitation wavelength. The performance of the material in the photocatalytic degradation of two commercial dyes (methylene blue and rhodamine 6G) has been tested under sunlight radiation, showing promising results. Almost complete decolorization has been observed after 80 min of exposure, with no adsorption on the silica surface. (C) 2011 Elsevier B.V. All rights reserved.203151157Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FapitecCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES
Cytotoxicity on V79 and HL60 Cell Lines by Thiolated-beta-Cyclodextrin-Au/Violacein Nanoparticles
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)In vitro cytotoxicity of a supramolecular system composed by violacein complexed by,beta-cyclodextrin-thiol-protected gold nanoparticles (violacein @ beta-CD-S(CH(2))(6)-S-Au) on V79 and HL60 cell lines is described. The gold nanoparticles were prepared and modified in a single step involving reduction of tetrachloroaurate ions with sodium borohydride in the presence of thiol derivatized beta-cyclodextrin. Inclusion complexation of violacein into cyclodextrin cavities occurred by mixing an aqueous solution of the gold nanoparticles with an acetone solution of violacein, being evidenced by UV/visible absorption spectroscopy According to cell viability measurements based on the MTT assay (3-(4,5-dimethylthiazole-2-yl)-2,5-biphenyl tetrazolium bromide) the supramolecular system was found to maintain the cytotoxic effects compared to free violacein on HL60 cells and in addition is less cytotoxic to normal (V79) cells.13352358Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP
Inclusion complexes of pyrimethamine in 2-hydroxypropyl-beta-cyclodextrin: Characterization, phase solubility and molecular modelling
The inclusion complexation of pyrimethamine in 2-hydroxypropyl-beta-cyclodextrin has been investigated by 2D H-1 NMR, FTIR and UV/visible spectroscopy and also by molecular modelling methods (AM1, PM3, MM3). From the phase-solubility diagram a linear increase was observed in pyrimethamine aqueous solubility in the presence of 2-hydroxypropyl-beta-cyclodextrin, evidencing the formation of a soluble inclusion complex. According to the continuous variation method (Job's plot) applied to fluorescence measurements, a 1:1 stoichiometry has been proposed for the complex. Concerning the structure of the complex, a Cl-in orientation of pyrimethamine in the 2-hydroxypropyl-o-cyclodextrin cavity has been proposed from the theoretical calculations, being confirmed by two-dimensional H-1 NMR spectroscopy (ROESY). The thermal behaviour has also been studied, providing complementary evidences of complex formation. (c) 2007 Elsevier Ltd. All rights reserved.15175752575