Search Results (700)

Acute ischemic stroke is one of the leading causes of mortality and disability globally, characterized by a complex and temporally structured cascade of cellular and molecular events. Although reperfusion therapies have improved outcomes, their narrow therapeutic window and limited availability leave many patients without effective treatment, highlighting the need for effective neuroprotective strategies capable of targeting multiple interconnected pathways. Melatonin has been proposed as a potential adjunctive neuroprotective agent based on its pleiotropic properties, modulating cellular signaling networks including antioxidant, anti-inflammatory, mitochondrial stabilizing, and BBB-preserving effects. Melatonin regulates key signaling pathways, thereby coordinating cellular responses to injury in multiple stages of ischemic pathophysiology, positioning it as a potential adjunctive therapy. Preclinical studies consistently demonstrate reductions in infarct volume, preservation of neuronal architecture, and improvements in neurological outcomes. However, clinical evidence remains limited to a small number of clinical trials, which suggest safety and possible early neurological benefit but are underpowered to determine long-term efficacy. Importantly, translational gaps persist regarding optimal dosing, duration of administration, and alignment with the temporal dynamics of post-ischemic injury. This review integrates current knowledge on the cellular and molecular mechanisms underlying the potential neuroprotective actions and its role as a pleiotropic modulator of ischemic injury. Full article

We review the structure of pseudoscalar mesons within an algebraic model formulated in the light-front framework. The approach provides a unified description of leading-twist parton distribution amplitudes, light-front wave functions, generalized parton distributions, parton distribution functions, elastic electromagnetic form factors, charge radii, and impact-parameter space distributions, all obtained from the same underlying Bethe–Salpeter wave-function representation. The analysis covers light mesons $(\pi ,K)$, the mixed $\eta$–${\eta }^{\prime }$ system, heavy–light states $(D,D_s,B,B_s,B_c)$, and heavy quarkonia $({\eta }_c,{\eta }_b)$, thereby enabling a systematic study of quark-mass effects, flavor-symmetry breaking, and the transition from emergent hadronic mass to heavy-quark dynamics. Where available, results are compared with experimental measurements, functional methods such as lattice-QCD calculations and Dyson–Schwinger Equation formalism, and other phenomenological approaches. The algebraic model thus offers a transparent, symmetry-preserving, and analytically tractable framework for connecting the longitudinal, transverse-momentum, and spatial structure of pseudoscalar mesons across all quark-mass regimes. Full article

This paper presents the mechatronic design, mathematical modeling, parameter identification, and nonlinear position control of an open-architecture biaxial shake table capable of generating base acceleration along two orthogonal horizontal directions. The shake table is tailored for engineering research and education. Addressing the limitations of proprietary “black-box” systems, the platform is constructed using standard industrial components (HLTNC-CNC modules and NEMA 23 BLDC motors) to ensure reproducibility. A core contribution is the characterization of the system’s nonlinear dynamics to enhance tracking fidelity. The mathematical model, derived via the Euler–Lagrange formulation, incorporates viscous and Coulomb friction phenomena, which are critical for accurately reproducing zero-velocity crossings in seismic signals. System parameters are identified using the Recursive Least Squares (RLS) algorithm combined with State Variable Filters (SVFs) to process the regression vector. To enable precise closed-loop performance, a nonlinear state observer incorporating the identified friction dynamics is designed for velocity estimation. Furthermore, a Computed Torque Control (CTC) strategy is synthesized and compared against a conventional Proportional-Velocity (PV) controller. Experimental validations using historical ground motions, including the 1986 Colima earthquake, confirm that the CTC strategy reduces the maximum absolute tracking error by more than 75% compared to the PV approach, bounding the peak error to $0.36\mathrm{mm}$ across both axes. Furthermore, in high-amplitude scenarios, the proposed model-based approach achieved an RMS tracking error reduction of more than 83%. These results validate the proposed platform as a reliable and accessible tool for structural dynamics testing. Full article

As food demand increases, agricultural practices have evolved, prompting increased exploration of sustainable ecological techniques and utilization of plant-associated microorganisms. In this context, plant fitness has been enhanced by plant growth-promoting microorganisms (PGPM), which stimulate growth through direct mechanisms, such as improved nutrient availability and phytohormone production, as well as indirect mechanisms, including protection against phytopathogens and suppression of soil-borne diseases. However, these innate capabilities of PGPM can be further improved through genomic modification or editing. This article reviews advances in the genomic engineering of plant-beneficial microorganisms as tools to enhance their positive effects on crop performance and environmental remediation. The genetic modification strategies analyzed here include random mutagenesis, targeted genome editing (such as CRISPR-Cas), gene over-expression, genome shuffling, RNA interference, metabolic pathway engineering, and synthetic biology approaches. These tools have enabled the optimization of functions, such as nitrogen fixation, phosphate solubilization, secondary metabolite production, biocontrol, stress tolerance, and bioremediation. However, we propose expanding the discussion of their regulation and use in various countries. Additionally, these modifications must be efficient and safe for the beneficial microbiota associated with the target crop, as well as for humans, animals, and the environment, all of which depend on sustainable agricultural practices. Full article

Biological invasions are among the main threats to freshwater biodiversity, yet ecological patterns associated with assemblage structure and high relative abundances of non-native fishes in spring ecosystems remain insufficiently documented. We evaluated seasonal variation in community composition, reproductive traits, and trophic interactions in La Zarcita springs, part of the Natural Protected Area Laguna de Zacapu, central Mexico. Bimonthly sampling was conducted, including stomach content analysis and reproductive trait assessment. A total of 14 fish taxa were recorded (seven native and seven non-native), with the assemblage numerically dominated by Oreochromis niloticus (30%), Pseudoxiphophorus bimaculatus (24%), and Xiphophorus hellerii (14%). Overall diet composition did not differ significantly between taxa classified as native and non-native (PERMANOVA, p > 0.05), consistent with overlap in resource use within the assemblage. Exploratory assemblage-level analyses detected differences in omnivory index values among taxa grouped according to species origin (LMM, p < 0.05). Reproductive analyses detected variation in fertility values (GLMM, p < 0.05), reproductive activity (Wilcoxon test, p < 0.05), gonadosomatic index values, and Fulton’s condition factor values (LMM, p < 0.01) among taxa within the assemblage. Physicochemical variables varied seasonally but were not significantly associated with trophic composition, condition factor values, or reproductive traits in the statistical analyses performed. Overall, the results document variation in reproductive characteristics and trophic patterns among taxa within this urbanized spring system and highlight the value of assemblage-level ecological studies for understanding fish community structure in small freshwater habitats. Full article

This study examines the impact of increasing photovoltaic (PV) penetration on the transient stability of the IEEE 9-bus power system. Synchronous machines are modeled with standard subtransient dynamics, while PV units are represented as current-limited grid-following inverters. Transient stability is assessed through the Critical Clearing Time (CCT) and the post-fault dynamic behavior, obtained from time-domain simulations carried out in MATLAB/Simulink^® R2023b. Two permanent three-phase faults are considered: a primary contingency on line 7–5 and a secondary contingency on line 9–6, introduced to assess the robustness of the observed trends across different fault locations. The results show an increase in CCT as PV generation progressively replaces the active power supplied by synchronous machines, whose inertia is therefore maintained: from 210 ms (0% PV) to 440 ms (25%)/1080 ms (40%) at bus 5, 410 ms (25%)/1130 ms (40%) and 290 ms (25%)/650 ms (40%) at buses 6 and 8, respectively, demonstrating that the penetration site is a key factor for system stability. For distributed penetration among the three buses, CCT values of 340 ms (25%) and 1020 ms (40%) highlight the significant influence of PV placement at bus 8. The fault on line 9–6 consistently yields higher CCT values across all scenarios, confirming the robustness of these trends independently of fault location. Although an overall increase in CCT was observed, higher PV penetration also led to more pronounced oscillations and operability issues after the fault. In particular, 75% of the penetration scenarios under the fault on line 9–6 do not meet the active power recovery requirements of IEEE 1547-2018 and IEEE 2800-2022, a result more severe than that observed for the fault on line 7–5. These results underscore that a higher CCT does not guarantee operational compliance, and that stability-oriented control strategies—such as grid-forming operation, fast active power support, and dynamic voltage control—remain essential. They also suggest that planning practices should favor interconnections electrically closer to the slack generator. Overall, a high PV penetration level—modifying only the operating point of synchronous machines—allows longer fault durations to be tolerated; however, appropriate siting of PV units and the adoption of advanced inverter controls could mitigate the observed oscillations and post-fault operability challenges. Full article

Electrospun composites are desirable materials for drug delivery applications. Regarding microbial infections as a case study, the antibacterial effect is enhanced by physical attributes of electrospun meshes, namely, a high surface area-to-volume ratio and porosity, 3D topography, and customized surface functions. Beyond mimicking nanostructured fibers, the delivery of antibiotics from such composites enhances antibacterial efficacy, sustained release kinetics, and reduced wound infection while minimizing side effects. Concern over antibiotic resistance and the insufficient availability of pharmaceutical agents for effective infection treatment is increasing worldwide. A significant number of publications have reported the fabrication of electrospun composites to mitigate bacterial pathogenesis. However, from a structural and morphological perspective, the implications of electrospinning approaches for antibiotic delivery have not been reviewed. This proposal presents a comparative study of the different assemblies induced by electrospinning, enabling the development of platforms for administering antibacterial agents. The primary objective is to conduct a comprehensive examination of the considerations involved in electrospinning-based manufacturing of drug delivery systems and antibiotic loading, ensuring a thorough design process that accounts for composite processability, monitoring methods for kinetic behavior analysis and modeling, and biological considerations for pre-clinical in vitro characterization. Full article

The Spodoptera frugiperda multiple nucleopolyhedrovirus (SfMNPV) is an important pathogen of the fall armyworm and is used as the basis for biological insecticides. In this study, we examined the relationship between the size–frequency distribution of SfMNPV occlusion bodies (OBs) and their insecticidal characteristics when collected at the end of the replication cycle. Exposure of OBs to 40%, 70%, and 90% (wt/wt) glycerol had no effect on OB pathogenicity. Glycerol density gradient (50–100%) centrifugation was used to separate OBs into two fractions. OBs recovered from the upper fraction of the gradient had a significantly smaller median cross-sectional area than those harvested from the lower fraction. These fractions also differed significantly in their size–frequency distributions. The OB concentration–mortality response of S. frugiperda second instars did not differ significantly between the two fractions or with non-centrifuged OBs. The median survival time was similar for insects inoculated with OBs from the upper and lower fractions but was significantly shorter in insects inoculated with non-centrifuged OBs. The proportion of mature OBs (67–71%) and the number of viral genome copies (1.33–1.40 × 10⁸ copies/µL) did not differ significantly between the upper and lower OB fractions. These findings suggest that altering the size–frequency distribution by density gradient centrifugation is not a useful technique for selecting large OBs with high insecticidal activity as part of the baculovirus insecticide production process. Future studies should evaluate a range of OB size separation techniques to determine their effects on OB insecticidal characteristics. Full article

This article analyzes the information provided by the sedimentary sequences of 29 lakes in central Mexico, 10 of which are currently paleolakes. During the Late Quaternary, the lakes of central Mexico experienced environmental changes driven by global and local climatic and geological processes, showing regional trends of wet and dry periods. Paleoenvironmental reconstructions are based on the use of 20 indicators, including diatoms, pollen, geochemistry, mineralogy, granulometry, magnetic susceptibility, and isotopes. Seven major episodes are recognized in the historical evolution of the lakes of central Mexico: i. Late Miocene–Pliocene: A period that includes the formation of large lakes in central Mexico by volcano tectonic activity under a regime of continuous humidity. ii. Pleistocene–Drought and climatic variability of the interglacial period. iii. Drying and successive lacustrine transgression during the Last Glacial Maximum. iv. Spatial climate variability in the Heinrich 1 period. v. Lake regression and expansion of terrestrial vegetation in the Bølling–Allerød period. vi. Transgression of lakes of central Mexico during the Younger Dryas and mid-Holocene periods. vii. Late Holocene: A period that includes lake desiccation influenced by the impact of human activities. The analysis of the data allows us to propose six challenges for the scientific community in future research of central Mexico. Full article

Background: Climate change has contributed to the global resurgence of dengue, with a spike of more than 14.4 million dengue cases. This study aimed to analyze the association between dengue frequency with climatic factors, circulating serotypes, and disease severity in northwestern Mexico. Methods: A retrospective time-series study was conducted using dengue molecular diagnostic data reported between September 2017 and January 2025 by the Laboratorio de Apoyo a la Vigilancia e Investigación Epidemiológica del Centro de Investigación Biomédica de Occidente, Mexico. Data included dengue frequency, serotype distribution, and clinical severity across seven states in northwestern Mexico (Colima, Guanajuato, Jalisco, Michoacán, Nayarit, Sinaloa, and Sonora). Meteorological data were obtained from the Automatic Meteorological Stations of the National Water Commission. Associations between dengue frequency and climatic variables were evaluated using linear regression models. Statistical analyses were performed using SPSS v24 and R v3.5. Results: In Jalisco, minimum, mean and maximum temperatures, as well as precipitation, were significant predictors of dengue cases, explaining approximately 21.7% of the variance (adjusted R² = 0.217, p < 0.001). In Colima and Michoacán, precipitation showed no predictive value. In Guanajuato, the maximum temperature was excluded from the model (adjusted R² = 0.226). Models for Nayarit, Sinaloa, and Sonora excluded two or more climatic variables, with adjusted R² values of 0.111, 0.151, and 0.049, respectively. Conclusions: Climatic conditions and epidemiological time trends explain a modest proportion of dengue cases in northwestern Mexico, with the strongest association observed in Jalisco. Additional determinants, including vector ecology, host immunity, circulating serotypes, population mobility, and public health interventions, should be considered to better understand dengue dynamics. Full article

The ecological interaction between plants and herbivores has promoted the evolution of defense and offense characteristics of both parties. Specialized metabolites, including volatile organic compounds (VOCs), constitute a key defensive mechanism of plants, helping to reduce/prevent damage by herbivores and indirectly attracting their natural enemies. However, in the absence of herbivores, as occurs in invaded ranges, natural selection may favor the reduction in costly chemical defenses. Here, we assessed the production of VOCs in both damaged and undamaged leaves of plants of Datura stramonium from Mexico (native) and Spain (non-native). The emissions of VOCs were detected and compared, along with the induction extended to neighboring undamaged leaves. A total of 45 VOCs were detected and differences in chemical diversity and concentration between plants of different origin and between damaged and undamaged leaves. Notably, native populations exhibited greater VOCs diversity and higher emission levels than non-native populations, highlighting population-specific differences in both constitutive and induced chemical defenses. Expression analysis of the gene implicated in terpenoid biosynthesis (DsTPS10) demonstrated damage-induced upregulation. Gene expression patterns coupled with metabolic profiles suggest a potential defense capability of native populations as compared with non-native populations of recent evolution in the absence of the D. stramonium’s coevolved herbivores. Full article

Global population growth poses major challenges to agricultural systems, demanding more efficient strategies to secure food production. Conventional approaches have relied heavily on chemical inputs; however, their overuse disrupts ecosystems, threatens biodiversity, and undermines human and environmental health. To ensure sustainable productivity, it is essential to explore alternative approaches that leverage microbial functions to enhance plant growth and resilience. Bacteria are among the most abundant soil microorganisms, playing central roles in biogeochemical cycles and plant health. While well-studied phyla such as Pseudomonadota, Actinomycetota, and Bacillota have been widely applied as biofertilizers and biocontrol agents, members of the phylum Bacteroidota remain comparatively understudied despite being consistently abundant in plant-associated microbiomes. This review synthesizes current knowledge on Bacteroidota, highlighting their taxonomy, ecological diversity, contributions to nutrient cycling, and mechanisms that promote plant growth, as well as biotic and abiotic stress tolerance. We also discuss the limitations that hinder their application, particularly challenges in cultivation and isolation, and outline future research directions to harness their potential for sustainable agriculture. Full article

This paper presents a sizing and optimization methodology for LCL filters tailored to high-capacity modular power systems. The approach prioritizes the strategic selection of the resonance frequency, an asymmetric inductance design, and strict harmonic current limits. The methodology is validated through a case study simulation of a 126 MW photovoltaic plant in a region of Mexico, analyzing its 2.34 MW inverter architecture. The simulations show that precise capacitor sizing for reactive power management, combined with a passive resistive damping strategy, ensures compliance with grid interconnection standards (IEEE 1547) and power quality standards (IEC 61000). This approach simplifies practical implementation by eliminating the need for complex active damping control algorithms. Additionally, dynamic decoupling is validated through time-domain step responses, and frequency-domain sensitivity analysis confirms robust stability margins even under ±20% variations in passive parameters. Ultimately, the system achieves voltage total harmonic distortion (THD) levels below 0.18%, demonstrating a scalable solution for maintaining grid stability. Full article

Ultraviolet (UV) radiation is a main environmental factor responsible for skin damage, leading to oxidative stress, inflammation, and impairment of the skin barrier function. Furthermore, many components in sunscreen may accumulate in aquatic systems, causing environmental pollution. Therefore, the identification of novel natural bioactives that counteract these effects and can be useful as effective adjuvants in sunscreen formulations is of particular interest. Morin (1), a natural flavonoid, represents an attractive scaffold for modifications to enhance its biological activity. Herein, we aimed to investigate the effects of combining the flavonoid 1 and its derivative, morin semicarbazone (2), with the carotenoid fucoxanthin (FX) on UVB-exposed HaCaT keratinocytes. All compounds exhibited higher radical scavenging activity compared to Trolox. In this cell model, the phenolic–carotenoid combinations provided greater photoprotection than individual compounds, significantly enhancing cell viability and reducing necrosis, FX-2 emerged as the most potent combination, as evidenced by a marked reduction in reactive oxygen species (ROS) and malondialdehyde (MDA) levels, likely mediated through the activation of the nuclear factor erythroid 2-related factor 2/Heme oxygenase-1 (Nrf2/HO-1) signaling pathway. Furthermore, the tested treatments exerted enhanced anti-inflammatory effects by significantly reducing interleukin-6 (IL-6), cyclooxygenase 2 (COX-2), and matrix metalloproteinase-9 (MMP-9) mediators, with FX-2 being the most active combination. In conclusion, our findings highlight the protective effects of the combinations of these phenolics with the carotenoid FX against UVB radiation and support their potential application as natural active ingredients in sunscreen formulations. Full article

Food safety systems are undergoing a profound and urgent transformation, shifting from traditional end-product inspection models toward integrated, preventive, and predictive approaches supported by digital, genomic and data-driven technologies. Conventional frameworks face increasing limitations in the context of globalized supply chains, climate variability, emerging hazards, and growing sustainability demands. This structured narrative review critically examines the technological and governance trends driving the transition toward digital and predictive food safety systems, with particular emphasis on their implications for sustainability. Key enabling technologies (including artificial intelligence (AI), whole-genome sequencing (WGS), Internet of Things (IoT)-based monitoring, blockchain-enabled traceability, and predictive analytics) are analyzed in terms of their capacity to enhance early hazard detection, real-time surveillance, and risk anticipation across the food supply chain. Beyond a descriptive overview, this review integrates technological, regulatory, and governance dimensions to identify convergence points, implementation barriers, and sustainability trade-offs, with particular attention to small and medium-sized enterprises and low- and middle-income countries. Furthermore, a four-level Digital Maturity Framework is proposed to conceptualize progressive stages of technological integration, providing a structured pathway for the evolution from reactive to predictive food safety systems. While digital and predictive approaches offer significant potential to reduce food losses, improve transparency, and strengthen evidence-based decision-making, their effective implementation remains constrained by infrastructure gaps, data governance challenges, regulatory fragmentation, and unequal access to digital capabilities. Achieving resilient and sustainability-oriented food safety systems will therefore require coordinated innovation, regulatory harmonization, and inclusive digital transformation strategies. Full article