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421.
Freitas CS Baggio CH Mayer B dos Santos AC Twardowschy A Santos CA Marques MC 《Natural product communications》2011,6(9):1253-1254
H+, K(+)-ATPase enzyme is a therapeutic target for the treatment of gastric disturbances. Several medicinal plants and isolated compounds inhibit the acid gastric secretion through interaction with the proton pump. In order to add new properties to some natural constituents, five compounds, a benzylated derivative of vincoside, a diterpene (abietic acid) and three alkaloids (cephaeline, vinblastine and vindoline), were tested for their activities on gastric H+, K(+)-ATPase isolated from rabbit stomach. All the compounds inhibited H+, K(+)-ATPase activity with varied potency. The IC50 value for benzylvincoside was 121 (50-293) microM, and for abietic acid 177 (148-211) microM. The alkaloids cephaeline, vinblastine and vindoline inhibited the H+, K(+)-ATPase activity with IC50 values of 194, 761 and 846 microM, respectively. The results suggest that benzylvincoside, abietic acid and cephaeline can be important sources for the development of anti-secretor agents. 相似文献
422.
Felipe A. Santos Paula M. Lima Renato C. F. Neves Paula M. Moraes Carlos A. P��rez Marcelo O. A. Silva Marco A. Z. Arruda Gustavo R. Castro Pedro de Magalh?es Padilha 《Mikrochimica acta》2011,173(1-2):43-49
An investigation was made on plasma samples obtained after protein separation. The proteome of the plasma of Nile tilapia (Oreochromis niloticus) was separated by 2D PAGE, and manganese and zinc in protein spots was qualitatively and quantitatively determined by synchrotron radiation X-ray fluorescence (SR-XRF) and graphite furnace atomic absorption spectrometry (GFAAS). Manganese and zinc are present in four and six plasma protein spots, respectively. These ions are bound to proteins with molecular weights ranging from 19 to 70?kDa and with isoelectric point (pI) ranging from 4.7 to 6.3. The concentrations of manganese and zinc bound to these proteins as determined by GFAAS following acid digestion of the spots range from 0.8 to 2.6?mg of manganese, and from 1.0 to 6.3?mg of zinc, respectively, per g of protein. Figure
2D-Page Plasma 相似文献
423.
Ivana Cesarino Fernando C. Moraes Sergio A. S. Machado Juliano PassarettiFilho Arnaldo A. Cardoso 《Electroanalysis》2011,23(6):1512-1517
A new electrochemical methodology has been developed for the detection of ozone using multiwalled carbon nanotubes (MWCNT). The method presented here is based on the reaction of ozone with indigo blue dye producing anthranilic acid (ATN). The electrochemical profile of ATN on an electrode of glassy carbon (GC) modified with MWCNT showed an oxidation peak potential at 750 mV vs. Ag/AgCl. An analytical method was developed using differential pulse voltammetry (DPV) to determine ATN in a range of 50–400 nmol L?1, with a detection limit of 9.7 nmol L?1. Ozonated water samples were successfully analyzed by GC/MWCNT electrode and the recovery procedure yielded values between of 96.5 and 102.3 %. 相似文献
424.
Caroline Costa Moraes Joana da Costa Ores Jorge Alberto Vieira Costa Susana Juliano Kalil 《Chromatographia》2011,73(3-4):307-312
In order to study the relationship between spinal cord injury and the change of nerve growth factor (NGF), an analytical method for NGF by capillary electrophoresis-based immunoassay (CEIA) with laser-induced fluorescence (LIF) was developed. Having been dissolved in phosphate buffer solution and concentrated with vacuum freeze-drying, NGF in spinal cord of rat was allowed to react with NGF monoclonal antibody labeled with fluorescence isothiocyanate (FITC). Then the immuno-complex, FITC-labeled anti-NGF and FITC were separated and determined by LIF-CEIA using Kiton red as the internal standard. The linear range of the method was 2?C30?ng?mL?1 and the limit of detection was 0.35?ng?mL?1. The relative standard derivations for relative migration time and relative fluorescence intensity ratio were 7.98% and 6.52%, respectively. The contents of NGF from spinal cord of rat were determined by both the proposed method and Western blotting. The results with the two methods agreed well. The spiked recoveries of the samples were 88.5?C116.3%. The proposed method was rapid, precise and inexpensive. 相似文献
425.
Alex Neves Junior Mariana Santos Lemos Romildo Dias Toledo Filho Eduardo de Moraes Rego Fairbairn Jo Dweck 《Journal of Thermal Analysis and Calorimetry》2013,113(2):659-665
This work complements a quantitative thermogravimetric study of the first 24 h of hydration of a high initial strength and sulphate resistant Portland cement (HS SR PC) using non-conventional differential thermal analysis (NCDTA) and Vicat needle method. Different water/cement (W/C) ratios from 0.35 to 0.85 were used to evaluate the most indicated operating conditions to maximize calcium hydroxide production for further use in CO2 capture. Thermogravimetric analysis data performed at 4 and 24 h of hydration were also compared to the NCDTA and Vicat data for each kind of paste, to analyze the influence of the W/C ratio on the simultaneous hydration and setting process. The increase of the W/C ratio increases the induction time retards the solidification and setting processes but increases the hydration degree as the W/C ratio is increased from 0.45. At 24 h, products prepared with 0.35 W/C ratio present a little higher hydration degree than those prepared with W/C = 0.45, because of the highest level of temperature in the reacting mixture in the former case, during the first 8 h. There is a practical limit of W/C = 0.66 to prepare the pastes, due to a limit of the miscibility between HS SR PC and water, above which, the excess of water forms a separated phase that does not interfere in the hydration process. 相似文献
426.
Ivana Cesarino Heloisa V. Galesco Fernando C. Moraes Marcos R. V. Lanza Sergio A. S. Machado 《Electroanalysis》2013,25(2):394-400
A new biosensor has been developed by a simple electrocodeposition of multiwalled carbon nanotubes (MWCNT), polypyrrole (PPy) and laccase (Lac) on the platinum (Pt) electrode surface. The neurotransmitter biosensor was applied to the detection of dopamine in urine samples using differential pulse voltammetry (DPV). The Pt/MWCNT/PPy/Lac biosensor exhibited a detection limit of 0.14 µM, which is an adequate level for monitoring dopamine in urine. Reproducibility and repeatability values of 2.9 % and 1.7 %, respectively, were obtained compared to the conventional procedure. The proposed biosensor was successfully applied in the determination of dopamine in urine, and the obtained results were in full agreement with those from the HPLC procedure. 相似文献
427.
María D. Acosta Pablo Galindo Luiza A. Moraes 《Journal of Mathematical Analysis and Applications》2014
In this paper we introduce and study the notion of homogeneous Tauberian polynomial, aiming at extending the concept of Tauberian operator. Such notion is characterized in terms of the polynomial topology for which we prove a Banach–Alaoglu type theorem. A number of examples show that the behavior of Tauberian polynomials differs from that of Tauberian operators. 相似文献
428.
Dr. Fernando Henrique Cincotto Dr. Fernando Cruz Moraes Prof. Dr. Sergio Antonio Spinola Machado 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(16):4746-4753
A novel material for the electrochemical determination of endocrine disruptors using a composite based on graphene oxide modified with cadmium telluride quantum dots has been evaluated. The morphology, structure and electrochemical performance of the composite electrodes were characterised by transmission electron microscopy, dynamic light scattering, UV‐visible absorption spectra, fluorescence spectra, Raman spectra and cyclic voltammetry. The dynamic light scattering, transmission electronic microscopy and spectrophotometric measurements all showed good distribution of the quantum dots with a small particle size. The electrochemical measurements demonstrated the high performance of the composite response in the presence of a light source. Differential pulse voltammetry allowed the development of a method to determine 17β‐estradiol levels in the range from 0.2 to 4.0 μmol L ?1 with a detection limit of 2.8 nmol L ?1 (0.76 μg L ?1). 相似文献
429.
Trapped in Imidazole: How to Accumulate Multiple Photoelectrons on a Black‐Absorbing Ruthenium Complex
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Linda Zedler Dr. Stephan Kupfer Dr. Inês Rabelo de Moraes Dr. Maria Wächtler Prof. Dr. Rainer Beckert Prof. Dr. Michael Schmitt Prof. Dr. Jürgen Popp Prof. Dr. Sven Rau Prof. Dr. Benjamin Dietzek 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(13):3793-3799
Ruthenium dyes incorporating a 4H‐imidazole chromophore as a ligand exhibit a spectrally broad absorption in the UV/Vis region. Furthermore, they show the ability to store two electrons within the 4H‐imidazole ligand. These features render them promising molecular systems, for example, as inter‐ or intramolecular electron relays. To optimize the structures with respect to their electron‐storage capability, it is crucial to understand the impact of structural changes accompanying photoinduced charge transfer in the electronic intermediates of multistep electron‐transfer processes. The photophysical properties of these (reactive) intermediates might impact the function of the molecular systems quite substantially. However, the spectroscopic study of short‐lived intermediates in stepwise multielectron‐transfer processes is experimentally challenging. To this end, this contribution reports on the electrochemical generation of anions identical to intermediate structures and their spectroscopic characterization by in situ resonance Raman and UV/Vis spectroelectrochemistry and computational methods. Thereby, an efficient two‐electron pathway to the 4H‐imidazole electron‐accepting ligand is identified. 相似文献
430.
Ademar Wong Anderson M. Santos Tiago A. Silva Fernando C. Moraes Orlando Fatibello-Filho Maria D. P. T. Sotomayor 《Electroanalysis》2023,35(1):e202200165
This work reports the construction of screen-printed electrode (SPE) modified with carbon black (CB) and magnetic Fe3O4 nanoparticles coated with molecularly imprinted polymer (mag@MIP) based on an alternative low-cost approach. The proposed device was used for the sensitive and selective voltammetric determination of the antibiotic ciprofloxacin. The results obtained from cyclic voltammetry pointed to the improvement of the SPE response toward the irreversible oxidation of ciprofloxacin after the modification of the electrode surface with CB-based film and the magnetic preconcentration of mag@MIP containing adsorbed ciprofloxacin molecules. Compared to the non-molecularly imprinted sensor (mag@NIP), the presence of cavities selective for ciprofloxacin recognition in the mag@MIP nanoparticles accounted for the improvement in analytical signal of the molecularly imprinted sensor. The application of differential pulse voltammetry for ciprofloxacin determination yielded a linear response in the concentration range of 0.5 to 7.0 μmol L−1. The repeatability and interference tests results showed that the proposed electrochemical sensor has good measurement accuracy and selectivity. The proposed device was applied for the voltammetric determination of ciprofloxacin in river water and synthetic urine samples, where recovery rates close to 100 % were recorded for all the samples. The quantification data obtained from the application of the proposed voltammetric method were quite consistent with those of the HPLC reference method. 相似文献