Brachycephalic syndrome (BS) in dogs is characterized by the combination of primary and secondary upper respiratory tract abnormalities and may result in significant upper airway obstruction. It can trigger inspiratory dyspnea, culminating in secondary respiratory distress, soft tissue edema, upper airway obstruction, turbulent airflow, inspiratory noise, and even death. These changes lead to increased resistance of the air passages, which can cause elevation of pulmonary pressure and clinical manifestations attributable to pulmonary hypertension. The consequence is right-sided cardiac remodeling (Cor pulmonale) with possible progression to right congestive heart failure. To investigate the effects of BS on the cardiovascular system, 28 animals were recruited for a prospective study and assigned to either the Brachycephalic Group (BG), composed of 22 French bulldogs with BS or the Control Group (CG), which was composed of 6 healthy Beagle dogs. All animals underwent a detailed physical examination, as well as laboratory analyses, electrocardiography, echocardiography, chest radiography and indirect measurement of systemic arterial blood pressure. The most relevant finding was a lower PaO2 (90.6±12.9mmHg) in BG as compared to CG (104.9±5.2), (p≤0.05), possibly attributable to hypoventilation due to anatomical alterations.

In this work, a thermal reduction method was developed to obtain reduced graphene oxide (rGO) with 2 or 3 layers from graphene oxide (GO). The GO X-ray diffraction (XRD) patterns presented diffraction peak at 2θ = 10°, which is related to (002) reflection. After heat treatment under nitrogen (N 2 (g)) atmosphere, this peak was shifted to 2θ = 25°, presenting an interlayer distance of 3.8 Å, associated to GO reduction. BET analysis of modified GO samples identified an average pore diameter of 45.38 Å and surface area of 23.06 m 2 /g. In the case of rGO 1 , rGO 2 and rGO 3 samples, they presented surface areas from 32.47 to 612.74 m 2 /g and an average pore diameter of 108.21-149.54 m 2 /g. Thermogravimetric analysis (TGA) indicated a higher mass loss between 150 and 230 °C. Raman spectra showed ID/IG ratios of rGO samples were higher than GO (1.36-GO; 1.45-rGO 1 , 1.87-rGO 3 ) due to reducing GO and increasing sp 2 clusters. XPS analysis revealed that the main carbon species in the samples were sp 2 -type bonds (14.99 at% for the GO and 47.85 at% for rGO 3 ). The FTIR spectra of rGO 1 , rGO 2 and rGO 3 samples presented peaks at 3454.22 cm −1 (hydroxyl) and 1077.43 cm −1 (C-O).

A redução térmica de óxido de grafeno (GO) para o óxido de grafeno reduzido (rGO) é um passo importante no processamento para fabricar muitos materiais e dispositivos à base de grafeno. Neste trabalho, o GO foi sintetizado a partir do método de Hummers modificado, e as amostras foram tratadas termicamente à temperatura de 200°C, com uma rampa de aquecimento de 10°/min, e pressão de 10 kPa, durante o tempo de 15 e 30 minutos. A caracterização de GO pelo DRX exibiu apenas um pico em 10°, do conjunto de planos GO (002), e a TGA demonstrou que o GO possui 10% de moléculas de água, voláteis e 26,77% de grupos com oxigênio. As amostras de rGO indicaram a perda de massa em 100 e 200°C na TGA e uma menor intensidade na absorção em 3489 cm-1 na FTIR.