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Envenoming caused by snakebites is a very important neglected tropical disease worldwide. The myotoxic phospholipases present in the bothropic venom disrupt the sarcolemma and compromise the mechanisms of energy production, leading to myonecrosis. Photobiomodulation therapy (PBMT) has been used as an effective tool to treat diverse cases of injuries, such as snake venom-induced myonecrosis. Based on that, the aim of this study was to analyze the effects of PBMT through low-level laser irradiation (904 nm) on the muscle regeneration after the myonecrosis induced by Bothrops jararacussu snake venom (Bjssu) injection, focusing on myogenic regulatory factors expression, such as Pax7, MyoD, and Myogenin (MyoG). Male Swiss mice (Mus musculus), 6–8-week-old, weighing 22 ± 3 g were used. Single sub-lethal Bjssu dose or saline was injected into the right mice gastrocnemius muscle. At 3, 24, 48, and 72 h after injections, mice were submitted to PBMT treatment. When finished the periods of 48 and 72 h, mice were euthanized and the right gastrocnemius were collected for analyses. We observed extensive inflammatory infiltrate in all the groups submitted to Bjssu injections. PBMT was able to reduce the myonecrotic area at 48 and 72 h after envenomation. There was a significant increase of MyoG mRNA expression at 72 h after venom injection. The data suggest that beyond the protective effect promoted by PBMT against Bjssu-induced myonecrosis, the low-level laser irradiation was able to stimulate the satellite cells, thus enhancing the muscle repair by improving myogenic differentiation.

The notional area of field emission is an important parameter to correlate characteristic current density to the emission current, linking field emission theories to experimental observations. Recently, it has been reported that the notional area of emission contributes to the high brightness of large diameter emitters. Thus, it is necessary to understand how the notional area of emission depends on physical and geometrical parameters. In this work, we carried out numerical simulations to evaluate the notional area, A n, considering cold field electron emission from a hemisphere on a cylindrical post (HCP) emitter in an array. An HCP is suitable to model classically carbon nanotubes or carbon nanofibres-like emitters. We provide the dependence of A n on a wide range of physical and geometrical parameters, namely: the separation between the HCP emitters, the aspect ratio, radius, local work function and the macroscopic emission current. We explain the behavior of A n as a function of these parameters and show in which cases A n can be considered nearly constant. Our numerical results are within the framework of the standard Fowler-Nordheim (FN) theory and can simplify the modeling of the field emission phenomenon, because it directly relates simulation predictions to the currents observable experimentally. Also, this work provides information for experimentalists that can be useful to check the validity of the Schottky-Nordheim (SN) barrier upon the elementary FN theory.

The pathogenesis of myonecrosis caused by myotoxins from bothropic venom is associated with local extracellular matrix (ECM) disintegration, hemorrhage, and inflammation. Search for alternative methods associated with serum therapy is mandatory to neutralize the fast development of local damage following snakebites. The experimental use of photobiomodulation therapy (PBMT) in murine models has shown promising results relative to structural and functional recovery from bothropic snakebite-induced myonecrosis. This study pioneered in using Raman and Fourier transform infrared (FTIR) spectroscopies to characterize biochemical alterations in the gastrocnemius that had been injected with Bothrops jararacussu venom and exposed to local PBMT. Results show that vibrational spectra from lyophilized and diluted venom (1307 cm −1) was also found in the envenomed gastrocnemius indicating venom presence in the unirradiated muscle 48 h post-injection; but any longer visible after PBMT at this time exposure or 72 h post-injection regardless irradiated or not. Raman and FTIR analyses indicated that the bands with higher area and intensity were 1657 and 1547 cm−1 and 1667 and 1452 cm−1, respectively; all are assignments for proteins, especially collagen, and are higher in the PBMT-exposed gastrocnemius. The infrared spectra suggest that laser treatment was able to change protein in tissue and that such change indicates collagen as the main target. We hypothesize that the findings reflect remodeling of ECM with key participation of collagen and faster tissue recovery for an anabolic condition.

We report a technique of fabrication of Al nanoislands of dimensions as small as 3 nm. Thin Al foils were anodized from both the surfaces under conditions suitable for the growth of porous alumina. Unanodized Al nanoislands were thus formed at the interpore regions and characterized by transmission electron microscopy. The method allows control over the distribution and the size of the nanoscale islands through the parameters of the anodization process, and automatic passivation by surrounding alumina.

Foi desenvolvido um sistema automatico de aquisicao e controle de dados para viabilizar a caracterizacao da emissividade eletronica em catodos frios em câmara de ultra alto vacuo. O circuito desenvolvido conta com uma interface USB e porta de comunicacao RS-232 virtual, sendo comando programado em Matlab. A instrumentacao desenvolvida teve como motivacao: i) aumentar a confiabilidade dos procedimentos de leitura da corrente de emissao de campo em amostras de materiais nanoestruturados; ii) garantir a reprodutibilidade dos ensaios; iii) preservar a integridade das amostras e do proprio instrumento; iv) mitigar erros existentes no processo de aquisicao dos dados; v) prover uma familia de curvas de forma automatizada para diferentes regioes de amostra, assim estudar uniformidade. Os principais desafios encontrados durante os trabalhos relacionaram-se com a definicao da topologia do circuito de entrada, da forma da isolacao galvânica, interferencias e tratamento dos dados adquiridos. A instrumentacao desenvolvida foi testada e os resultados sao apresentados neste trabalho.

Results Histological data confirmed that the non-functionalized MWCTN had been absorbed and kept retained into the phagocytes of the peri-pancreatic lymph nodes, spleen and liver, causing a granulomatous inflammatory response. Even though no differences were found in the frequency of the development of clinical diabetes or in the morphological characteristics of the pancreatic insulitis, female NOD mice treated with MWCTN presented a significant higher fluctuation of the average glycaemia compared to the control group during the entire study (p