The State University of Minas Gerais. (Portuguese: Universidade do Estado de Minas Gerais, UEMG) is a Brazilian public university. It is the third largest university in the state of Minas Gerais, second only to the Federal University of Minas Gerais and the Federal University of Uberlândia. It was founded in 1989 in Belo Horizonte, Minas Gerais, Brazil. Besides Belo Horizonte, its campuses are distributed across several cities in the Minas Gerais states..
Hydrothermal humic acids (HHA) have attracted attention due to their redox-active properties and potential for lignocellulosic waste valorization. However, the effects of alkaline hydrothermal extraction temperature on their molecular organization and antioxidant activity remain poorly understood. This study investigated the influence of extraction temperature (120-200 degrees C) on the structural characteristics and antioxidant properties of HHA produced from sugarcane straw hydrochar, with humic acid obtained by conventional alkaline extraction at 90 degrees C (HA90) included for comparison. HHA were characterized by SEM/EDS, elemental analysis, TGA, FTIR, and one-and two-dimensional NMR spectroscopy, together with measurements of total acidity and carboxylic and phenolic hydroxyl groups. Total phenolic content was determined, and antioxidant activity was evaluated by DPPH radical scavenging. Extraction yields remained similar among treatments, whereas increasing temperature promoted changes in chemical composition, thermal stability, and the distribution of oxygen-containing functional groups. 1H NMR showed an increase in the relative contribution of the delta 1.6-3.0 region, from 13.35% in HA90 to 21.13% in HHA200. HSQC and HMBC analyses indicated the presence of methoxyl groups associated with lignin-derived oxygenated aromatic structures. Increasing extraction temperature enhanced total phenolic content from 85.32 to 146.56 mg GAE g-1 and improved antioxidant activity, with IC50 decreasing from 1.34 to 0.72 g L-1. Exploratory correlation analysis indicated significant associations between antioxidant activity, phenolic content, phenolic hydroxyl groups, and other chemical constituents. The alkaline hydrothermal extraction modified the molecular organization and antioxidant properties of HHA, supporting the valorization of sugarcane residues into redox-active humic materials.
Environmental disturbances may cause physiological, behavioral and demographic changes in wildlife populations, which may translate into changes in community structure and ecosystem functioning. Little is known about fire effects on physiological parameters, and their consequences for population dynamics and persistence. Due to ongoing climate change and anthropogenic pressures, fire has become more intense and frequent in several Brazilian biomes, including the Cerrado. This suggests an urgent need to assess fire’s impact on organism physiology, especially nutritional indicators. We used a longitudinal database (9 years) to test the effects of fire on the body condition of the long-tailed climbing mouse Rhipidomys macrurus at the Panga Ecological Station (Uberlândia/Brazil). The effects of sex and climatic season were also tested. Overall, we failed to corroborate our hypothesis, as body condition was not significantly affected by repeated fires. Several mechanisms may account for this result: (1) reduced intraspecific competition after repeated fire events, due to abrupt density changes, (2) fire acting as a selective agent, increasing mortality of individuals with lower body condition and nutritional reserves, and (3) behavioral strategies that may compensate for energy loss and reduce negative fire impacts on body condition. Furthermore, we cannot discard the possibility of a false negative, due to reduced statistical power resulting from low sample size after fire events. Finally, other fitness metrics may be more affected by fire than body condition. Our results support the theory that body condition may be an unreliable indicator of habitat quality, disturbance, and individual or population health.
Bovine mastitis is one of the major challenges in dairy production, causing significant economic losses and emphasizing the need for alternatives to the indiscriminate use of antibiotics. Palo Santo (Bursera graveolens) essential oil (BEO) presents recognized biological properties that can be enhanced through nanoengineered delivery systems. This study aimed to chemically characterize the BEO of B. graveolens, develop a nanoemulsion containing the essential oil (BEO-NE), and evaluate its toxicological, antinociceptive, and antimicrobial activities against bovine mastitis–associated pathogens. The chemical composition of the BEO was determined by gas chromatography–mass spectrometry (GC–MS), identifying D-limonene (38.70
Brazil is structuring a biochar value chain at the intersection of climate policy and industrial innovation. Although the deployment of this value chain remains at an early stage, recent regulatory advances, particularly the Brazilian Emissions Trading System (SBCE) and emerging technical standards, create new opportunities for biochar to be recognized as a carbon removal strategy. This Comment argues that Brazil’s current momentum represents a critical inflection point, but its success depends on resolving three key challenges: (i) scientific uncertainties and limitations in monitoring, reporting and verification (MRV); (ii) regulatory gaps in standardization and certification; and (iii) the economic mechanisms required to transform biochar into a credible climate asset. By examining recent technological developments, pilot-scale evidence, and institutional arrangements, we highlight both the potential and the constraints that will determine whether biochar can scale as a robust carbon removal solution and a multifunctional technological platform in tropical systems.
Rice (Oryza sativa L.) is an essential food crop, usually grown in flooded soils. However, these environments, especially with low pH, favor iron (Fe) toxicity due to the low redox potential, which increases the Fe2+ availability. Excessive Fe concentrations are highly detrimental, compromising the growth, physiology, and productivity of rice plants. In this context, dopamine has emerged as a bioactive molecule with the potential to mitigate stresses in plants. Therefore, the objective of this study was to evaluate whether the exogenous application of dopamine attenuates oxidative damage in the photosynthetic apparatus of rice leaves subjected to excess Fe, as well as to analyze anatomical changes, production of reactive oxygen species (ROS), activity of antioxidant enzymes, and the nutritional status of plants. Fe excess caused the accumulation of this element in roots and leaves, reducing the uptake of other essential nutrients. However, the application of dopamine significantly increased the nutritional status while reducing the accumulation of Fe in plants. In the anatomy, dopamine promoted improvements in root structures, primarily in the thickness of the root epidermis (21%), as well as enhancements in leaves, including an increase in chlorophyll parenchyma (11%). Exogenous dopamine also minimized damage to the photosynthetic apparatus, increasing the levels of photosynthetic pigments and significantly increasing the effective quantum yield of PSII photochemistry (13%) and electron transport rate (13%). In gas exchange, the dopamine application in plants under Fe excess promoted increases in the net photosynthetic rate and water use efficiency with increases of 14% and 25%, respectively. The antioxidant defense was intensified by dopamine, with increases in the activities of superoxide dismutase (33%), catalase (29%), ascorbate peroxidase (75%) and peroxidase (17%). In parallel, there was a reduction in the ROS accumulation, including superoxide (14%) and hydrogen peroxide (8%), as well as malondialdehyde (37%) and electrolyte leakage (4%). Finally, the biomass was negatively impacted by excess Fe; however, dopamine promoted increases in stem and root growth, proving its effectiveness in mitigating the toxic effects of Fe in rice.
