The thermal reactivity of kerogen is primarily determined by skeletal bond strength and intermolecular interactions. To elucidate this, we established a multiscale framework integrating high-fidelity molecular modeling, Density Functional Theory (DFT), Reactive Molecular Dynamics (ReaxFF) simulations, and non-isothermal kinetic analysis. Three-dimensional molecular models for Type II1, II2, and III kerogens were constructed under rigorous experimental constraints. DFT calculations revealed significant electronic structural heterogeneity: Type III kerogen exhibited a high average skeletal bond order of 1.17 and a charge standard deviation of 0.0918, indicating pronounced structural rigidity and strong electrostatic polarization. In contrast, Type II1 kerogen was characterized by a flexible aliphatic content exceeding 54% and a radical attack index (f 0) more than four times that of Type III, implying abundant reactive sites. Iso-conversional kinetic analysis yielded systematically increasing pyrolysis activation energies (Ea) for Type II1, II2, and III kerogens, measured at 234.34, 240.67, and 247.10 kJ/mol, respectively. General correlation analysis indicates that macroscopic Ea scales positively with skeletal bond order and electrostatic polarization, while negatively with flexible domain abundance and radical initiation capacity. These findings indicate that thermal stability is dominated by skeletal rigidity and electrostatic confinement; conversely, reactivity is driven by aliphatic flexibility and radical generation potential. Guided by these electronic properties, strategies utilizing polarity-matched hydrothermal fluids and active hydrogen capping are proposed to overcome high energy barriers and suppress condensation, mechanisms further validated by ReaxFF simulations. These findings provide molecular-level insights for optimizing in-situ kerogen conversion.
Soils are essential for food production and environmental sustainability, yet agricultural practices can modify their physicochemical and biological properties and favor the accumulation of pesticide residues and transformation products. This study assessed agricultural soils from the Altiplano Potosino (Mexico) using an integrated approach that combined physicochemical characterization, enzymatic activity profiling, targeted multiresidue pesticide analysis, and high-resolution metabolomics. Four agricultural soils (SF, SI, LA, and EH) and one reference potting soil (M) were analyzed. Soil properties included pH, electrical conductivity, organic matter, cation exchange capacity, and nutrient content. Enzymatic activities associated with C, N, P, and S cycles (β-glucosidase, urease, leucine aminopeptidase, phosphatases, and arylsulfatase) were measured as indicators of functional soil health. Targeted GC–MS/MS and LC–MS/MS were used to screen for 430 pesticides, while suspect and nontarget high-resolution mass spectrometry was applied to detect potential transformation products. Parent pesticides were detected only in SF and SI; LA and EH showed no active ingredients. However, metabolomics revealed diverse pesticide-related metabolites in all soils, including LA and EH, indicating historical contamination and ongoing degradation. The detection of 4,4′-DDE in SI confirmed legacy DDT inputs. Transformation products of dimethoate, fluopyram, acetamiprid, and deltamethrin reflected different degradation stages. The potting soil (M) showed the highest enzymatic activities, whereas SI ranked highest among agricultural soils, consistent with greater nutrient availability and microbial activity. Overall, the absence of parent compounds did not indicate contaminant-free soils. Integrating soil indicators, enzymatic activities, and metabolomics provides a robust framework to evaluate soil health, legacy contamination, and degradation dynamics, with potential applications in improving soil monitoring programs and supporting evidence-based environmental management and policy decisions.
Jatropha vernicosa Brandegee, Euphorbiaceae, is an endemic plant used for its medicinal properties in Baja California Sur, Mexico. The sap is used for its wound-repairing effect by the native inhabitants. However, there are no scientific reports about its phytochemicals, cytotoxicity, and wound-healing properties of this important plant in México. The objective of this study is to evaluate J. vernicosa sap properties and wound-healing potential with three experiments: in vitro, in vivo, and ex vivo bioassays. Chemical, phytochemical, antioxidant potential, and cytotoxicity were analyzed in lyophilized J. vernicosa sap. Wound closure was analyzed using Detroit 548 cultured cells over time, and the wound-healing properties of J. vernicosa ointment were evaluated in vivo on Balb/c mice for 6 days. After 6 days, spleen leukocytes were isolated to analyze immunological parameters. Lyophilized J. vernicosa sap is rich in polyphenols such as flavonoids, tannins, and saponins, and has antioxidant properties. Its chemical composition is mainly composed of carbohydrates. Jatropha vernicosa sap is safe for cells at concentrations below 600 µg/ml. Interestingly, the cell culture experiment concluded that J. vernicosa sap extract induced a significantly higher rate of wound closure compared to the untreated control and the doxorubicin-treated group, particularly at 24 and 48 h post-scratch. The in vivo experiment showed that the wound area was smaller using J. vernicosa sap ointments compared with other treatments. Finally, immunological parameters after the ex vivo experiment show an anti-inflammatory or immunosuppressive effect. These results suggest that lyophilized J. vernicosa sap has biotechnological potential and wound-healing properties, and further studies are recommended to deepen the understanding of its biological activities and explore its possible applications.
The shrub oaks of Quercus section Quercus have been poorly studied in Mexico. Within these shrub oaks, Quercus microphylla and morphologically similar taxa (i.e., the Q. microphylla complex) still exhibit a great deal of taxonomic uncertainty related to species identity and delimitation. Quercus striatula is a name in this complex to which morphologically divergent population groups have been associated. Applying an integrative taxonomy approach, we used morphology and geometric morphometrics, genetic analyses with nuclear microsatellite markers, and ecological niche models, to establish the boundaries between morphologically different populations within Q. striatula, in conjunction with Quercus cordifolia, a morphologically close species. Our results support a clear separation of three taxa, which allowed us to propose Quercus oyamae as a new species for science, which corresponds to plants from the Mexican Plateau previously considered as Q. striatula. The new species is described and illustrated and a key for its identification is included.
Understanding the forces modulating the intraspecific correspondence between trophic niche and functional morphology is key to predicting how species may respond to climate change. Despite a strong diet–morphology correspondence being a common assumption of niche models, we still know little about how functional morphology predicts trophic niche within species. Here, we found that the relatively high and temporally consistent individual trophic specialization in Urotrygon rogersi was not driven by body size and sex. On the contrary, jaw shape and function were affected by sex and locality. These morphological changes occurred along the Z-axis, which underscores the importance of quantifying three-dimensional phenotypic variation within species. These morphofunctional differences could be driven by evolutionary and/or developmental constraints or represent advantages for both reproductive processes and the processing of prey items found in different substrates. Contrary to the diet-morphology correspondence found in fish species from species-poor communities and environments with relatively predictable prey dynamics, our results support theoretical expectations and findings of recent experimental studies suggesting that interindividual differences in digestive performance or behavior might have a more significant role than trophic morphology in driving patterns of intraspecific trophic variation in environments with high variability in prey dynamics and species-rich communities.
