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.

Electrical stimulation impairs early functional recovery and accentuates skeletal muscle atrophy after sciatic nerve crush injury in rats.

Abstract: Neuromuscular recovery after peripheral nerve lesion depends on the regeneration of severed axons that re-establish their functional connection with the denervated muscle. The aim of this study was to determine the effects of electrical stimulation (ES) on the neuromuscular recovery after nerve crush injury in rats. Electrical stimulation was carried out on the tibialis anterior (TA) muscle after sciatic nerve crush injury in a rat model. Six ES sessions were administered every other day starting from day 3 postinjury until the end of the experiment (day 14). The sciatic functional index was calculated. Muscle excitability, neural cell adhesion molecule (N-CAM) expression, and muscle fiber cross-sectional area (CSA) were accessed from TA muscle. Regenerated sciatic nerves were analyzed by light and confocal microscopy. Both treated (crush+ES) and untreated (crush) groups had their muscle weight and CSA decreased compared with the normal group (P < 0.05). Electrical stimulation accentuated muscle fiber atrophy more in the crush+ES than in the crush group (P < 0.05). N-CAM expression increased in both crush and crush+ES groups compared with the normal group (P < 0.05). Regenerated nerves revealed no difference between the crush and crush+ES groups. Nevertheless, functional recovery at day 14 post-injury was significantly lower in crush+ES group compared with the crush group. In addition, the crush+ES group had chronaxie values significantly higher on days 7 and 13 compared with the crush group, which indicates a decrease in muscle excitability in the crush+ES animals. The results of this study do not support a benefit of the tested protocol of ES during the period of motor nerve recovery following injury.

Controlled crystallization and ionic conductivity of a nanostructured LiAlGePO4 glass-ceramic

Abstract: A Li1.5[Al0.5Ge1.5(PO4)3] glass composition was subjected to several crystallization treatments to obtain glass–ceramics with controlled microstructures. The glass transition (Tg), crystallization onset (Tx) and melting (Tm) temperatures of the parent glass were characterized by differential scanning calorimetry (DSC). The glass has a reduced glass transition temperature Tgr = Tg/Tm = 0.57 indicating the possibility of internal nucleation. This assumption was corroborated by the similar DSC crystallization peaks from monolithic and powder samples. The temperature of the maximum nucleation rate was estimated by DSC. Different microstructures were produced by double heat treatments, in which crystal nucleation was processed at the estimated temperature of maximum nucleation rate for different lengths of time. Crystals were subsequently grown at an intermediate temperature between Tg and Tx. Single phase glass–ceramics with Nasicon structures and grain sizes ranging from 220 nm to 8 μm were then synthesized and the influence of the microstructure on the electrical conductivity was analysed. The results showed that the larger the average grain size, the higher the electrical conductivity. Controlled glass crystallization allowed for the synthesis of glass–ceramics with fine microstructures and higher electrical conductivity than those of ceramics with the same composition obtained by the classical sintering route and reported in literature.

Nanostructured carbon black for simultaneous sensing in biological fluids

Abstract: A novel material for the simultaneous electrochemical determination of ascorbic acid (AA), dopamine (DA), uric acid (UA) and paracetamol (PAR) using a composite based on carbon black film at glassy carbon electrode (CB/GC) has been evaluated. The morphology, structure and electrochemical performance of the composite electrodes were characterized by transmission electron microscopy, scanning electron microscopy, Raman spectra and cyclic voltammetry. The transmission electron microscopy and scanning electron microscopy images showed good distribution of the carbon black with a nanoscale particle size. The electrochemical measurements demonstrated the high-performance electrocatalytic of CB/GC electrode. Differential pulse voltammetry was applied to simultaneously detect AA, DA, UA and PAR levels in biological samples.