Purpose: To evaluate the influence of a 25% alpha-tocopherol antioxidant gel (AT) and a 50% DL-alpha-lipoic acid antioxidant solution (AL) on coronal fracture resistance and the integrity of the adhesive interface between coronal dentin and a universal adhesive system (Ambar Universal APS), compared with a 10% sodium ascorbate gel (AS), after internal bleaching with 35% or 40% hydrogen peroxide. Materials and methods: Two hundred bovine incisors were used: 80 teeth for fracture resistance and fracture pattern analyses, 80 crowns for resin tag evaluation, and 40 crowns for microtensile bond strength and failure mode analyses. Specimens were allocated according to hydrogen peroxide concentration (35% or 40%) and antioxidant protocol: control (CO), sodium ascorbate (AS), alpha-tocopherol (AT), and DL-alpha-lipoic acid (AL). Data were analyzed using appropriate statistical tests with a significance level of 5%. Results: Sodium ascorbate and alpha-tocopherol exhibited the highest fracture resistance and microtensile bond strength values, whereas sodium ascorbate promoted the greatest resin tag formation. The control groups showed the lowest values for the evaluated mechanical and adhesive properties. DL-alpha-lipoic acid demonstrated intermediate performance. No significant differences were observed between the 35% and 40% hydrogen peroxide protocols. Conclusion: The application of antioxidants after intracoronal bleaching resulted in higher fracture resistance and bond strength compared with the bleached control protocols. Under the experimental conditions evaluated, the sodium ascorbate and alpha-tocopherol protocols showed the most favorable overall performance.
Multicomponent (Sm,Nd)3(Nb,Ta)O7 was synthesized by high-energy mechanical milling and investigated from mechanochemical formation to compression up to 50 GPa. After 22 h of milling, X-ray diffraction reveals a highly nanocrystalline orthorhombic weberite described by the C2221 space group, with a mean crystallite size of approximately 20 nm. Annealing at 800 °C for 3 h increases the mean crystallite size to approximately 26 nm, enhances structural coherence, and sharpens the Raman response while preserving the average weberite structure. In situ synchrotron X-ray diffraction shows anisotropic compression of the C2221 phase, with the b axis more compressible than a and c, and a second-order Birch–Murnaghan bulk modulus B0 = 145(3) GPa up to 19.5 GPa. Above ∼21 GPa, weakening and broadening of characteristic weberite reflections, together with increasing peak overlap and diffraction-pattern simplification, mark a progressive structural reorganization extending to ∼31 GPa. The high-pressure state remains crystalline to 50 GPa and can be described by a Cmcm-compatible higher-average-symmetry orthorhombic metric, although the broadened diffraction patterns do not permit an unequivocal space-group assignment or a reliable high-pressure equation of state. Raman spectroscopy independently reveals progressive broadening and coalescence of framework-related bands, whereas high-frequency (Nb,Ta)–O stretching features remain detectable to 50 GPa. The combined results indicate pressure-induced structural symmetrization in which long-range weberite distortions are suppressed while local structural heterogeneity persists.
Anthracnose is the most devastating fruit disease affecting guava worldwide. The increasing restrictions on the use of synthetic fungicides, particularly during postharvest stages, call for innovative strategies to protect fruits and ensure global food security. Thus, this study aimed to compare pre- and post-inoculation vapor phase treatments of cinnamon (CIN) (Cinnamomum cassia), pepper rosemary (PEP) (Lippia sidoides), and clove (CLO) (Syzygium aromaticum) essential oils (EOs) with synthetic fungicide on guava anthracnose and postharvest quality. Additionally, in vitro assessments were made for EOs action on Colletotrichum siamense mycelial growth, conidial germination, hyphae morphology and membrane integrity, while monitoring the development of early infection structures on treated guava fruits 24 h after inoculation. PEP and CLO exhibited the strongest inhibitory effects on mycelial growth, whereas CIN was more effective in inhibiting conidial germination. While all EOs severely disrupted hyphae morphology, only PEP caused pronounced membrane damage. In contrast to CIN, CLO and PEP vapor phase reduced anthracnose severity in inoculated guavas after seven days of storage, although PEP also induced phytotoxic symptoms. Tebuconazole fungicide treatment showed the greatest reduction in lesion diameter and, together with CLO, delayed weight loss, softening, color change, soluble solids accumulation, and the decline in titratable acidity in guava. A higher rate of appressorial formation was observed in fruits treated with water and CIN compared to CLO and PEP. These findings demonstrate the promising potential of CLO vapor phase as an alternative strategy for postharvest management of guava anthracnose and provide new insights into the EOs antifungal modes of action.
Coatings that provide effective anti-corrosion barriers are essential for protecting metal surfaces. However, over time, the coated substrate can become susceptible to localized corrosion, while physical damage, such as cracks and scratches, reduces the effectiveness of the protective coating. In this work, intelligent systems based on epoxy-silica coatings were developed to confer long-term protection against corrosion of the AA7075 aluminum alloy, using a strategy combining a dense and effective passive barrier against the permeation of oxidizing species, and active protection by incorporation of the inhibitors Ce(IV) and Ce(III). Different characterization techniques were used to identify structural changes in the modified epoxy-silica nanocomposites. Excellent long-term corrosion protection performance was obtained in 0.6 mol L−1 NaCl solution, with electrochemical impedance spectroscopy analysis showing that impedance modulus on the order of 10 MΩ cm2 was maintained over a period of 400 days. Detailed investigation of the modified coatings revealed their self-healing ability after film corrosion damage and exposure of artificially scratched coatings to accelerated corrosion and salt spray testing, confirming the effectiveness of the Ce(III) and Ce(IV) agents for the long-term protection of epoxy-silica coatings.
Preimplantation embryos display acute microenvironmental sensitivity, dynamically coordinating metabolic pathways and epigenetic remodeling to maintain homeostasis. However, because early chromatin-modifying enzymes are vulnerable to external fluctuations, abrupt environmental shifts across major cellular transitions risk disrupting the substrate availability and redox synchronization required for faithful reprogramming. To address this problem, this study investigated the biological significance of environmental continuity during the critical transitions of in vitro maturation (IVM) and in vitro fertilization (IVF), examining how oxygen tension shapes the interplay between embryonic redox balance and the epigenome. Using a bovine model across a 2 & times; 2 factorial design (5% vs. 20% O2), we demonstrate that oxygen tension during IVM and IVF affects blastocyst yield, redox balance, and epigenetic mark profiles as distinct, independently regulated outcomes. Maintaining a stable 20% O2 atmosphere (M20F20) maximized blastocyst yields (50.63 +/- 4.55%) and was associated with the highest intracellular glutathione (GSH) levels and lowest reactive oxygen species (ROS), indicating superior antioxidant capacity. Conversely, shifting from high-oxygen IVM to low-oxygen IVF (M20F5) resulted in the lowest blastocyst rates, elevated ROS, and reduced GSH, suggesting that an abrupt oxygen transition imposes a compounded redox burden that exceeds the embryo's antioxidant buffering capacity. At the molecular level, repressive histone marks (H3K9me2/3) were higher in groups with consistent oxygen environments across IVM and IVF (M5F5 and M20F20) than in mismatched groups, regardless of the absolute oxygen level. Global DNA methylation (5 mC) was primarily driven by IVM oxygen tension, whereas 5-hydroxymethylcytosine (5hmC) responded to both IVM and IVF conditions. Notably, the M20F5 group exhibited elevated 5hmC levels and the poorest developmental outcomes, a pattern consistent with 'epigenetic stalling', in which TET-mediated demethylation may be initiated but fails to proceed to completion under redox-imbalanced conditions. We crossvalidaed these oxygen-dependent epigenetic responses in a somatic bovine fibroblast model, where oxygen tension modulated KDM6A expression. Together, these findings demonstrate that oxygen tension during the IVM and IVF stages independently shapes embryonic redox balance and epigenetic mark profiles, outcomes that are not predicted by blastocyst yield alone, and that an abrupt downward oxygen transition at IVF represents a specific point of vulnerability for epigenetic fidelity.
