The aim of this study was to evaluate the effects of sodium hyaluronate (HY), single-walled carbon nanotubes (SWCNTs) and HY-functionalized SWCNTs (HY-SWCNTs) on the behavior of primary osteoblasts, as well as to investigate the deposition of inorganic crystals on titanium surfaces coated with these biocomposites. Primary osteoblasts were obtained from the calvarial bones of male newborn Wistar rats (5 rats for each cell extraction). We assessed cell viability using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide assay and by double-staining with propidium iodide and Hoechst. We also assessed the formation of mineralized bone nodules by von Kossa staining, the mRNA expression of bone repair proteins, and the deposition of inorganic crystals on titanium surfaces coated with HY, SWCNTs, or HY-SWCNTs. The results showed that treatment with these biocomposites did not alter the viability of primary osteoblasts. Furthermore, deposition of mineralized bone nodules was significantly increased by cells treated with HY and HY-SWCNTs. This can be partly explained by an increase in the mRNA expression of type I and III collagen, osteocalcin, and bone morphogenetic proteins 2 and 4. Additionally, the titanium surface treated with HY-SWCNTs showed a significant increase in the deposition of inorganic crystals. Thus, our data indicate that HY, SWCNTs, and HY-SWCNTs are potentially useful for the development of new strategies for bone tissue engineering.

It has been demonstrated that carbon nanotubes (CNTs) associated with sodium hyaluronate (HY-CNTs) accelerate bone repair in the tooth sockets of rats. Before clinical application of HY-CNTs, it is important to assess their biocompatibility. Moreover, cardiac toxicity may be caused by the translocation of these particles to the blood stream. The aim of this study was to evaluate possible changes in cardiovascular function in male Wistar rats whose tooth sockets were treated with either CNTs or HY-CNTs (100 μg/mL, 0.1 mL). Blood pressure and heart rate were monitored in conscious rats 7 days after treatment. Cardiac function was evaluated using the Langendorff perfusion technique. The data showed no changes in blood pressure or heart rate in rats treated with either CNTs or HY-CNTs, and no significant changes in cardiac function were found in any of the groups. To confirm these findings, experiments were conducted in rats injected intraperitoneally with a high concentration of either CNTs or HY-CNTs (0.75 mg/kg). The same parameters were analyzed and similar results were observed. The results obtained 7 days following injection indicate that the administration of low concentrations of CNTs or HY-CNTs directly into tooth sockets did not cause any significant change in cardiovascular function in the rats. The present findings support the possibility of using these biocomposites in humans.

O objetivo do presente estudo foi verificar o efeito agudo do alongamento estático e facilitação neuromuscular propriocetiva (FNP) no desempenho do número de repetições máximas (RM) numa sessão de treino de força (STF). Seis visitas foram realizadas. Nas três primeiras adotou-se uma familiarização com os protocolos de alongamento e teste e reteste de 12RM. Os voluntários foram divididos aleatoriamente nas seguintes condições experimentais: a) protocolo de alongamento estático + STF; b) protocolo de alongamento FNP + STF; c) protocolo de aquecimento específico com 20 repetições a 30% da carga de 12RM + STF. Realizaram-se 3 séries de 12RM para cada exercício: leg press (LP), cadeira extensora (CE), mesa flexora (MF) e panturrilha (PT). Para o somatório do número de RM das 3 séries de cada exercício, diferenças significativas (p < .05) foram encontradas entre os métodos nos exercícios LP, CE e MF. Para o somatório do número de RM das três séries dos quatro exercícios encontraram-se diferenças significativas (p < .05) para EP vs. AE e FNP vs. AE. Ambos os métodos de alongamento diminuíram o desempenho, reduzindo os níveis de força. Desta forma, os alongamentos FNP e estático não devem ser recomendados antes de uma sessão de treino de força.

This study aimed to investigate the acute effect of static stretching (SS) and proprioceptive neuromuscular facilitation (PNF) in the performance of repetition maximum (RM) during a training session of force (TSF) for upper and lower limbs. Six sessions were conducted during the experiment period. At the first three sessions, a stretching protocol familiarization was adopted followed by 12 maximal repetitions test and retest. From the fourth session on, the following experimental protocols were applied: a) Static stretching + TSF; b) PNF stretching + TSF; c) specific warm-up with 20 repetitions (30% of 12 RM load) + TSF. The sessions included three sets of 12 RM for each exercise (leg press 45º, leg extension, leg curl and plantar flexion). It was observed significant differences (p< .05) between the stretching methods to the sum of (RM) of the three sets in leg press 45º, leg extension and leg curl. It was observed significant difference (p< .05) in the SRM on the three of four exercises at the EP vs. SS and PNF vs. SS situations. Both stretching methods decrease the subsequent strength performance, reducing its levels. Therefore, PNF and SS methods should not be recommended before a training session of force.

O conhecimento da erodibilidade dos solos (fator K) é de fundamental importância para a aplicação da equação universal de perdas de solo (EUPS). O objetivo deste trabalho foi verificar a adequação de diferentes métodos indiretos para estimativa da erodibilidade de solos com horizonte B textural (Bt) de várias regiões geográficas do Brasil. Coletaram-se amostras superficiais de 22 solos com Bt, cujo fator K foi determinado diretamente no campo. Realizaram-se diversas análises químicas e físicas, de modo que o fator K pudesse ser estimado por treze diferentes métodos indiretos. Correlacionaram-se os valores dos fatores K medidos no campo com os obtidos indiretamente. Verificou-se que nenhum dos métodos indiretos testados é adequado para a estimativa do fator K de todo o conjunto de solos com Bt estudados.

The assessment of the soil erodibility (K-factor) is essential for using the universal soil loss equation. The objective of this paper was to verify the adequacy of different indirect methods to estimate the K-factors of soils with argillic horizon from diverse geographic regions of Brazil. Superficial samples of 22 soils bearing argillic horizon were collected. The K-factors measured directly in the field of all these soils are already known. Several chemical and physical analyses were performed in order to calculate the K-factor by 13 indirect methods. The calculated K-factors were correlated with the direct K-factor value. It was verified that none of the indirect methods tested is suitable for estimating the K-factor of all studied soils with argillic horizon in Brazil.