Federal University of São Carlos

About: Federal University of São Carlos is a education organization based out in São Carlos, Brazil. It is known for research contribution in the topics: Population & Microstructure. The organization has 16471 authors who have published 34057 publications receiving 456654 citations. The organization is also known as: UFSCar & Federal University of São Carlos.

Relationship between short-range order and ease of nucleation in Na2Ca2Si3O9, CaSiO3 and PbSiO3 glasses

Abstract: A relationship between the short-range order around the modifier cations and the crystal nucleation tendency in silicate glasses is demonstrated. New extended X-ray absorption fine spectroscopy (EXAFS) results on the local structure around calcium and lead atoms were obtained and analyzed for both vitreous and crystalline samples. Three different silicate systems were studied: wollastonite (CaSiO3) and soda-lime–silica (Na2Ca2Si3O9), for which volume nucleation is easily observed and lead metasilicate (PbSiO3) for which nucleation occurs only on the sample surfaces in typical laboratory conditions. In the glasses that have a high nucleation tendency (Na2Ca2Si3O9 and CaSiO3), the local structures of these modifier cations are similar to their short-range order in the isochemical crystalline phases, whereas the local structure in the glass that presents a low nucleation tendency (PbSiO3) is quite different from that of its isochemical crystal phase.

A Step Towards the Automated Diagnosis of Parkinson's Disease: Analyzing Handwriting Movements

Abstract: Parkinson's disease (PD) has affected millions of people world-wide, being its major problem the loss of movements and, consequently, the ability of working and locomotion. Although we can find several works that attempt at dealing with this problem out there, most of them make use of datasets composed by a few subjects only. In this work, we present some results toward the automated diagnosis of PD by means of computer vision-based techniques in a dataset composed by dozens of patients, which is one of the main contributions of this work. The dataset is part of a joint research project that aims at extracting both visual and signal-based information from healthy and PD patients in order to go forward the early diagnosis of PD patients. The dataset is composed by handwriting clinical exams that are analyzed by means of image processing and machine learning techniques, being the preliminary results encouraging and promising. Additionally, a new quantitative feature to measure the amount of tremor of an individual's handwritten trace called Mean Relative Tremor is also presented.

Electrocatalytic Behavior of Glassy Carbon Electrodes Modified with Multiwalled Carbon Nanotubes and Cobalt Phthalocyanine for Selective Analysis of Dopamine in Presence of Ascorbic Acid

Abstract: This work describes the development, electrochemical characterization and utilization of a cobalt phthalocyanine modified carbon nanotube electrode for the quantitative determination of dopamine in 0.2 mol L � 1 phosphate buffer contaminated with high concentration of ascorbic acid. The electrode surface was analyzed by cyclic voltammetry and electrochemical impedance spectroscopy which showed a modified surface presenting a charge transfer resistance of 500 W, against the 16.46 kW value found for the bare glassy carbon surface. A pseudo rate constant value of 5.4 � 10 � 4 cm s � 1 for dopamine oxidation was calculated. Voltammetric experiments showed a shift of the peak potential of DA oxidation to less positive value at 390 mV as compared with that of a bare GC electrode at 570 mV. The electrochemical determination of dopamine, in presence of ascorbic acid in concentrations up to 0.1 mol L � 1 by differential pulse voltammetry, yielded a detection limit as low as 2.56 � 10 � 7 mol L � 1