Screening and determination of sulphonamide residues in bovine milk samples using a flow injection system

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Effect of grinding with diamond-disc and -bur on the mechanical behavior of a Y-TZP ceramic

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Voltammetric sensor for simultaneous determination of p-phenylenediamine and resorcinol in permanent hair dyeing and tap water by composite carbon nanotubes/chitosan modified electrode

p-Phenylenediamine (PPD) and resorcinol (RSN) are hair dye precursors of permanent dyeing more used worldwide. The present work describes a simple and economic voltammetric sensor for simultaneous determination of both components in commercial hair dyeing and tap water at low concentrations. PPD and RSN are oxidized at + 0.17 and + 0.61 V vs. Ag/AgCl at glassy carbon electrode coated by composites of multiwall carbon nanotubes with chitosan (MWNTs-CHT/GCE), which anodic currents density normalized are 10% and 70% higher in relation to the unmodified electrode, respectively. The calibration curve for simultaneous determination of PPD and RSN showed linearity between 0.55 and 21.2 mg L-1 with detection limits of 0.79 and 0.58 mg L-1 to PPD and RSN, respectively. The relative standard deviations found for ten determinations were of 0.73 and 2.35% to 2.70 mg L-1, and 0.87 and 1.08% to 15.96 mg L-1 to PPD and RSN, respectively. The voltammetric sensor was applied to determination of PPD and RSN in tap water and commercial hair dyeing samples and the average recovery for these samples was around 97%. The products generated from PPD and RSN reaction such as was p-quinonediimine and bandrowski base were detected by LC-MS/MS and UV-vis spectrophotometry. (C) 2014 Published by Elsevier B.V.

Sensitive flow-injection spectrophotometric analysis of bromopride

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Method validation using weighted linear regression models for quantification of UV filters in water samples

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Simultaneous determination of epinephrine and dopamine by electrochemical reduction on the hybrid material SiO2/graphene oxide decorated with Ag nanoparticles

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

Electroanalytical determination of bumetanide employing a biomimetic sensor for detection of doping in sports

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Multielemental evaluation of garbage bags by EDXRF

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Optimized design of substrate-integrated hollow waveguides for mid-infrared gas analyzers

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Effect of platelet-rich plasma on the healing of mandibular defects treated with fresh frozen bone allograft: a radiographic study in dogs

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Controle de qualidade em equipamentos mamográficos

Nowadays the mammography is the most effective way of revealing early breast cancer. The image in this kind of exam is gotten trough a x-ray sheaf of low energy, however, the suitable visualization of the interesting structures by the radiologist is not always possible due several factors that appears since the mamma composition until the equipments limitation. The regulation 453/98 sets quality control tests and limits of acceptation that guarantee a good development of the mammographys. The purpose of this study is the 3D principle ( Diagnostic, Dose and Dollar), that means, an improved diagnosis, a dose reduction in the patient and a cost decrease for the Institution. In this study was made the quality control tests set by the Regulation in two mammography equipments from Hospital das Clínicas da Faculdade de Medicina de Botucatu (HCFMB - UNESP). The results reached in this research were used in the renovation process of quality stamp in mammography granted by Colégio Brasileiro de Radiologia (CBR) to the diagnosis by image from the HCFMB – UNESP

Development and application of a screen-printed electrode modified with MWCNT for the electrocatalytic detection of thiram

Interest in the electronic properties of carbon nanotubes has increased in recent years. These materials can be used in the development of electrochemical sensors for the measurement and monitoring of analytes of environmental interest, such as pharmaceuticals, dyes, and pesticides. This work describes the use of homemade screen-printed electrodes modified with multi-walled carbon nanotubes (MWCNT) for the electrochemical detection of the fungicide thiram. The electrochemical characteristics of the proposed system were evaluated using cyclic voltammetry, with investigation of the electrochemical behavior of the sensor in the presence of the analyte, and estimation of electrochemical parameters including the diffusion coefficient, electron transfer coefficient (α), and number of electrons transferred in the catalytic electro-oxidation. The sensor response was optimized using amperometry. The best sensor performance was obtained in 0.1 mol L-1 phosphate buffer solution at pH 8.0, where a detection limit of 7.9 x 10-6 mol L-1 was achieved. Finally, in order to improve the sensitivity of the sensor, square wave voltammetry (SWV) was used for thiram quantification, instead of amperometry. Using SWV, a response range for thiram from 9.9 x 10-6 to 9.1 x 10-5 mol L-1 was obtained, with a sensitivity of 30948 µA mol L-1, and limits of detection and quantification of 1.6 x 10-6 and 5.4 x 10-6 mol L-1, respectively. The applicability of this efficient new alternative methodology for thiram detection was demonstrated using analyses of enriched soil samples.

Analysis of fluoxetine and norfluoxetine in human plasma by HPLC-UV using a high purity C18 silica-based SPE sorbent

This paper reports on the development and validation of a simple and sensitive method that uses solid phase extraction (SPE) and liquid chromatography with ultraviolet detection to analyze fluoxetine (FLX) and norfluoxetine (NFLX) in human plasma samples. A lab-made C18 SPE phase was synthesized by using a sol–gel process employing a low-cost silica precursor. This sorbent was fully characterized by nuclear magnetic resonance (NMR), Fourier-transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM) to check the particles' shape, size and C18 functionalization. The lab-made C18 silica was used in the sample preparation step of human plasma by the SPE-HPLC-UV method. The method was validated in the 15 to 500 ng mL 1 range for both FLX and NFLX using a matrix matched curve. Detection limits of 4.3 and 4.2 ng mL 1 were obtained for FLX and NFLX, respectively. The repeatability and intermediary precision achieved varied from 7.6 to 15.0% and the accuracy ranged from 14.9 to 9.1%. The synthesized C18 sorbent was compared to commercial C18 sorbents. The average recoveries were similar (85–105%), however the lab-made C18 silica showed fewer interfering peaks in the chromatogram. After development and validation, the method using the lab-made C18 SPE was applied to plasma samples of patients under FLX treatment (n ¼ 6). The concentrations of FLX and NFLX found in the samples varied from 46.8–215.5 and 48.0–189.9 ng mL 1 , respectively.

Simultaneous determination of chromium and nickel in medicinal plants by slurry sampling graphite furnace atomic absorption spectrometry

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

Two-and tridimensional analysis of periapical repair after endodontic surgery

Objective The aim of this study was to evaluate repair after endodontic surgery using two- and tridimensional imaging methods. Materials and methods Periapical radiographs and cone beam computed tomography (CBCT) were performed before the surgeries and after 48 h (baseline), 4 months, and 8 months. The area (square millimeters) of periapical lesions in CBCT and in radiographs was compared regarding the percentage of repair. In the CBCT, multiple areas were converted to volume. Repeated-measures analyses and paired t tests (α=0.05) were used to compare the methods. Correlation coefficients were calculated between the periods of evaluation within the CBCT volumetric analysis. Bland-Altman plots were used to compare the methods, based on the 95 % limits of agreement for the difference of the means. Results Baseline showed a larger lesion volume (192.54 mm3 ) than 4-month (79.79 mm3 ) and 8-month (47.51 mm3 ) periods. No differences were found in the percentage of repair in the first 4 months and after 8 months. The volumetric analysis showed a higher percentage of repair when the first and last 4 months were compared. No differences were found in the percentage of repair by area in the CBCTs. Repair of 73 % was obtained after 8 months. Similar results were observed by the Bland-Altman agreement analyses. Conclusions The percentage of repair varied after 8 months, when lower values were obtained by volumetric evaluation. Clinical relevance Considering the outcome at follow-up periods over 4 months, tridimensional evaluation by CBCT is more capable of determining the absence of periapical bone repair than conventional two-dimensional radiographs. Therefore, the use of CBCT would be suggested only for more complex cases with slower evolution of repair or for the association of factors that make prognosis difficult after surgery.