Synchrony of hand-foot coupled movements: is it attained by mutual feedback entrainment or by independent linkage of each limb to a common rhythm generator?

BACKGROUND: Synchrony of coupled oscillations of ipsilateral hand and foot may be achieved by controlling the interlimb phase difference through a crossed kinaesthetic feedback between the two limbs, or by an independent linkage of each limb cycle to a common clock signal. These alternative models may be experimentally challenged by comparing the behaviour of the two limbs when they oscillate following an external time giver, either alone or coupled together. RESULTS: Ten subjects oscillated their right hand and foot both alone and coupled (iso- or antidirectionally), paced by a metronome. Wrist and ankle angular position and Electromyograms (EMG) from the respective flexor and extensor muscles were recorded. Three phase delays were measured: i) the clk-mov delay, between the clock (metronome beat) and the oscillation peak; ii) the neur (neural) delay, between the clock and the motoneurone excitatory input, as inferred from the EMG onset; and iii) the mech (mechanical) delay between the EMG onset and the corresponding point of the limb oscillation. During uncoupled oscillations (0.4 Hz to 3.0 Hz), the mech delay increased from -7° to -111° (hand) and from -4° to -83° (foot). In contrast, the clk-mov delay remained constant and close to zero in either limb since a progressive advance of the motoneurone activation on the pacing beat (neur advance) compensated for the increasing mech delay. Adding an inertial load to either extremity induced a frequency dependent increase of the limb mechanical delay that could not be completely compensated by the increase of the neural phase advance, resulting in a frequency dependent increment of clk-mov delay of the hampered limb. When limb oscillations were iso- or antidirectionally coupled, either in the loaded or unloaded condition, the three delays did not significantly change with respect to values measured when limbs were moved separately. CONCLUSION: The absence of any significant effect of limb coupling on the measured delays suggests that during hand-foot oscillations, both iso- and antidirectionally coupled, each limb is synchronised to the common rhythm generator by a "private" position control, with no need for a crossed feedback interaction between limbs

Classificação automática de inclusões em aços – preparação de amostras com diferentes tipos de inclusões

O desenvolvimento de aços avançados requer um controle bastante elaborado da etapa do refino, em particular para o controle da formação das inclusões, que ocorrem através da interação entre o metal líquido e as diversas superfícies do equipamento (inclusões exógenas) ou pela solubilização de gases e outros elementos de liga que posteriormente se precipitam durante o vazamento do metal (inclusões endógenas). Padrões internacionais definem normas para classificação destas inclusões, utilizando métodos clássicos de comparação de quadros – chart comparison e medidas utilizando análise de imagens. No entanto, o processo definido por estas normas ainda é caracteristicamente manual. Estas normas classificam as inclusões de acordo com o tipo de inclusão nas classes A (sulfetos), B (alumina), C (silicatos) e D (óxidos); espessura ou diâmetro; formação de “strings” – seqüências de inclusões alinhadas na direção de laminação; severidade – uma medida da densidade de inclusões. O presente projeto de pesquisa foi desenvolvido em parceria com o grupo de pesquisadores da PUC-Rio que desenvolveu um método automático de classificação de inclusões em aços, com alta confiabilidade estatística, minimizando a interferência do usuário ao longo de todo o procedimento inicialmente baseado nas imagens padrão. O presente trabalho colaborou com uma segunda fase do trabalho que consiste em aplicar a rotina computacional desenvolvida em imagens reais contendo inclusões. Para isso as amostras de aços contendo inclusões foram preparadas metalograficamente e analisadas em MO. Desta maneira será possível fazer uma comparação entre os resultados da rotina automática para separar inclusões das diferentes classes das imagens reais e das imagens de referência da norma

Fibra em Gramíneas Forrageiras Tropicais.

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RESVERATROL INCLUSION COMPLEX WITH β-CYCLODEXTRIN (RCD): CHARACTERIZATION AND EVALUATION OF TOXICITY IN WISTAR RATS

Objective: The aim of this study was to characterise the resveratrol inclusion complex with β-cyclodextrin (RCD) and evaluate their toxicity in wistar rats.Methods: The RCD were prepared in ultra-turrax. For characterization of the RCD were used: Fourier transform infra-red Spectroscopy, Nuclear Magnetic Resonance (NMR), Differential Scanning Calorimetry (DSC) and X-ray powder diffraction. The RCD and others 4 treatments were performed by the chronic oral administration in 35 rats during 60 ds. After the treatments they were euthanized and the serum blood were collected to analyzed some hemogram and biochemical parameters including aspartyl aminotransferase (AST); alanine aminotransferase (AST); phosphatase alkaline (ALP); total bilirubin (TB); direct bilirubin (DB); total protein (TP); total cholesterol (TC), triacylglycerol (TAG), very low-density lipoprotein (VLDL), high-density lipoprotein (HDL), calcium, iron and phosphate using fully automated biochemistry analyzer.Results: The characterization results indicated a successful formation of the RCD. All hematological parameters analysed were within the normal values in all the groups. Furthermore, the hemogram and biochemical parameters were significantly (P>0.05) similar to the control group.Conclusion: The daily oral administration during 60 d of RCD are not harmful on blood parameters of Wistar rats. Thus, RCD can be used safely for treatment of some metabolic diseases

Characterization of collagenase blend enzymes for human islet transplantation

BACKGROUND: Efficient islet isolation represents a necessary requirement for successful islet transplantation as a treatment for type 1 diabetes. The choice of collagenase for pancreas digestion is critical for the isolation outcome, and Liberase is the most widely used enzyme, although large intra-batched variability in activity and efficiency has been observed. METHODS: The aim of this study was to characterize Liberase components and their relative role in pancreas digestion. Liberase batches were characterized by microelectrophoresis. RESULTS: By means of microelectrophoresis, we identified three main proteins each with different prevalences between batches. Two proteins were found to correspond to class I (CI) and one to class II (CII) collagenase. In a series of 163 islet isolations, we observed that the CII correlated with islet yield (P50 percentile, 15 of 36 preparations were transplanted, with 27 of 127 transplanted in the other cases (P=0.013). CONCLUSION: These results represent an important step toward the characterization of enzymes, with the final aim of identifying key components for a standardized produc