Search Results (109)

Green synthesis of gold nanoparticles (AuNPs) provides a significantly eco-friendly and low-impact counterpart to conventional chemical methods. In the present study, we synthesized gold nanoparticles using Schinus molle (P-AuNPs) aqueous extract as a reducing and stabilizing agent. The obtained nanoparticles were then stabilized by another biocompatible agent, the chiral amino acids L-cysteine (L-Cys-AuNPs) and D-cysteine (D-Cys-AuNPs), to estimate the potential of the surface modification for enhancing AuNPs surface chemistry and antimicrobial action. The synthesized gold nanoparticles were confirmed by UV-Vis spectroscopy, FTIR, XRD, and circular dichroism to validate their formation, crystalline structure, surface properties, and chirality. Physicochemical characterization confirmed the formation of crystalline AuNPs with size and morphology modulated by chiral functionalization. TEM and DLS analyses showed that L-cysteine-functionalized AuNPs were smaller and more uniform, while FTIR and circular dichroism spectroscopy confirmed surface binding and the induction of optical activity, respectively. L-Cys-AuNPs exhibited the highest antimicrobial efficacy against a broad spectrum of microorganisms, including Escherichia coli, Salmonella enterica, Listeria monocytogenes, Staphylococcus aureus, Staphylococcus epidermidis, and, notably, Candida albicans. L-Cys-AuNPs showed the lowest MIC and MBC values, highlighting the synergistic effect of chirality on biological performance. These findings suggest that L-cysteine surface engineering significantly enhances the therapeutic potential of AuNPs, particularly in combating drug-resistant fungal pathogens such as C. albicans. This research paves the way for the development of next-generation antimicrobial agents, reinforcing the relevance of green nanotechnology in the field of materials science and nanotechnology. Full article

Background: Breast cancer remains a major public health challenge in Latin America, where access to personalized risk assessment tools is still limited. This study aimed to evaluate the implementation of a polygenic risk score (PRS)-based stratification model combined with remote genomic counseling in Colombian women with sporadic breast cancer and healthy women. Methods: In 2023, an embedded mixed-methods observational study was conducted in Medellín involving 1997 women aged 40–75 years who underwent clinical PRS testing. The intervention integrated PRS-based risk categorization with individualized risk factor assessment and lifestyle recommendations delivered through a remote counseling platform. Results: PRS analysis classified 9.7% of women as high risk and 46% as low risk. Healthier lifestyle patterns were significantly associated with lower PRS categories (p = 0.034). Physical activity showed a protective effect (OR = 0.60, 95% CI: 0.5–0.8), while prior smoking, elevated BMI, and sedentary behavior were associated with higher risk. The counseling model achieved high delivery (93%) and satisfaction (85%) rates. Qualitative insights revealed improved understanding of genomic risk and greater engagement in preventive behaviors. Only one new case of breast cancer was detected among intermediate-risk participants, with a diagnostic lead time of 12 months. Conclusions: These findings support the feasibility, acceptability, and potential impact of integrating PRS and genomic counseling in cancer prevention strategies in middle-income settings. Full article

There is still a need to develop scenarios and models aimed at substituting fuelwood and reducing the use of fossil fuels such as liquefied petroleum gas (LPG), on which low-income rural households in the Global South often depend. The use of these fuels for cooking and heating in domestic and productive activities poses significant health and environmental risks. This study validated, in three different phases, the sustainability of a model for the production and use of biogas from the treatment of swine-rearing wastewater (WWs) on a community farm: (i) A Multi-Criteria Analysis (MCA), incorporating environmental, social/health, technical, and economic criteria, identified the main weighted criterion to C8 (use of small-scale technologies and low-cost access), with a score of 0.44 points, as well as the Tubular biodigester (Tb) as the most suitable option for the study area, scoring 8.1 points. (ii) Monitoring of the Tb over 90 days showed an average biogas production of 2.6 m³ d⁻¹, with average correlation 0.21 m³ Biogas kg Biomass⁻¹. Using the experimental biogas production rate (k = 0.0512 d⁻¹), the process was simulated with the BgMod model, achieving an average deviation of only 10.4% during the final production phase. (iii) The quantification of benefits demonstrated significant reductions in firewood use: in Scenario S1 (kitchen energy needs), biogas replaced 83.1% of firewood, while in Scenario S2 (citronella essential oil production), the substitution rate was 24.1%. In both cases, the avoided emissions amounted to 0.52 tons of CO_2eq per month. Finally, this study proposes a synthesised, community-based rural biogas framework designed for replication in regions with similar socio-environmental, technical, and economic conditions. Full article

Series elastic actuators (SEAs) represent a key technological solution to enhance safety, performance, and adaptability in robotic devices for physical training. Their ability to decouple the rigid actuator’s mechanical impedance from the load, combined with passive absorption of external disturbances, makes them particularly suitable for pediatric applications. In children aged 2 to 5 years—where motor control is still developing and movements can be unpredictable or unstructured—SEAs provide a compliant mechanical response that ensures user protection and enables safe physical interaction. This study explores the role of SEAs as a central component for imparting compliance and backdrivability in robotic systems designed for upper-limb training. A dynamic model is proposed, incorporating interaction with the user’s limb, along with a computed torque control strategy featuring integral action. The system’s performance is validated through simulations and experimental tests, demonstrating stable trajectory tracking, disturbance absorption, and effective impedance decoupling. The results support the use of SEAs as a foundational technology for developing safe adaptive robotic solutions in pediatric contexts capable of responding flexibly to user variability and promoting secure interaction in early motor development environments. Full article

This work presents a comprehensive evaluation of the heat-sealability of films developed from chañar brea gum (CBG), a biopolymer with potential for packaging applications. Heat sealability is a critical property in the packaging industry, as it directly determines the integrity and functionality of the final product. The films were prepared by the 10% casting method with the addition of glycerin, and heat sealing was performed at 140 °C using a heat sealer. Heat sealing was performed on 2 cm × 10 cm strips of chañar gum in the horizontal (CBG-H) and vertical (CBG-V) directions. This study employs a joint determination to explore the fundamental properties of the films, including proximate analysis, antioxidant capacity, FTIR, DSC, TGA-DTGA, XRD, mechanical testing, water vapor permeability, sorption, and biodegradability. By integrating the results of all these determinations, this study seeks to evaluate and explain the “intimate relationships”—i.e., the complex interconnections among the molecular structure, composition, thermal behavior, mechanical properties, and barrier properties of channier gum films—and how these fundamental properties dictate and control their heat sealability. The thermal stability of CBG is up to 200 °C, with a melting point of 152.48 °C. The interstrand spacing was very similar at 4.88 nm for CBG and 4.66 nm for CBG-H. The SEM images of the heat seal show rounded shapes on the surface, while in the cross section, it is homogeneous and almost without gaps. The WVP decreased from 1.7 to 0.37 for CBG and CBG-H, respectively. The Young’s modulus decreased from 132 MPa for CBG to 96.5 MPa for CBG-H. The heat sealability is 656 N/m, with a biodegradability of 4 days. This comprehensive approach is crucial for optimizing the sealing process and designing functional and efficient biodegradable packages. Full article

Wildlife-vehicle collisions (WVCs) threaten biodiversity, particularly in the Gulf of Mexico, where road expansion increases habitat fragmentation. This research analyzes WVC patterns in southeastern Mexico, estimating collision rates across road types and assessing environmental factors influencing roadkill frequency. Field monitoring in 2016 and 2023 recorded vertebrate roadkills along roads in Campeche, Chiapas, and Tabasco. Principal Component Analysis (PCA) and Generalized Additive Models (GAM) evaluated landscape influences on WVC occurrences. A total of 354 roadkill incidents involving 73 species of vertebrates were recorded, with mammals accounting for the highest mortality rate. Hotspots were identified along Federal Highway 259 and State Highways Balancán, Frontera-Jonuta, and Salto de Agua. Road type showed no significant effect. Land cover influenced WVCs, with cultivated forests, grasslands, and savannas showing the highest incidences. PCA identified temperature and elevation as key environmental drivers, while GAM suggested elevation had a weak but notable effect. These findings highlight the risks of road expansion in biodiversity-rich areas, where habitat fragmentation and increasing traffic intensify WVCs. Without targeted mitigation strategies, such as wildlife corridors, underpasses, and road signs, expanding infrastructure could further threaten wildlife populations by increasing roadkill rates and fragmenting habitats, particularly in ecologically sensitive landscapes like wetlands, forests, and coastal areas. Full article

In this study, composting as an alternative approach for managing mercury-contaminated biomass in water bodies affected by gold mining in the Choco department was evaluated. A single-factor experiment with three treatments containing varying amounts of Eleocharis interstincta biomass sourced from mercury-contaminated sites was designed. During the composting process, physicochemical parameters were monitored such as temperature, pH, and electrical conductivity, while analyzing the behavior of mercury through mass balance assessments. Additionally, we determined the bioavailability of mercury in the final compost and characterized the physicochemical parameters of each compost sample. The mercury mass balance indicated a decrease in the total mercury content in the initial biomass over the composting period of 170 days. However, the total mercury concentration in the final compost increased due to the transformation and subsequent reduction of the original biomass. Mercury speciation analysis revealed that mercury was predominantly associated with the less bioavailable fractions (F4 and F5), suggesting its stabilization and low availability to biota. Therefore, the final compost has the potential to restore degraded soils by improving moisture retention, porosity, and soil fertility, thereby promoting plant growth. However, it does not fully meet the national and international technical standards for solid organic fertilizers or compost. Full article

Food systems interact through multiple dimensions including food security, nutrition, and planetary health. This study aims to associate different dietary patterns with sustainable lifestyles in Latin America and Spain. This was an observational, analytical, multicenter, cross-sectional survey study, with a total of 6412 participants. A self-administered questionnaire was developed in an online format in the Google Docs interface. The questionnaire was divided into sections: (1) sociodemographic background: country of residence, age, sex, educational level, socioeconomic aspects, and place of residence; (2) body mass index classification; (3) dietary patterns (Western, vegetarian, vegan, ketogenic, Mediterranean, prudent, or paleolithic diets); and (4) the Sustainable Lifestyles Survey. Multivariate models were applied to adjust for potential confounding factors. The mean age of the participants was 35.2 years (SD 12.7). The majority of participants identified their dietary pattern as omnivorous (41.5%), followed by the Western diet (21.7%) and the Mediterranean diet (12.7%). Plant-based, vegan (β: 14.90; 95% CI: 9.75–20.05), and lacto egg (β: 12.08; 95% CI: 8.57–15.58) diets are significantly associated with a higher sustainability score compared to an omnivorous diet. In contrast, a Western diet is inversely associated (β: −5.63; 95% CI: −7.20 to −4.06). Finally, a vegan (Sub-score 1: β: 6.19; 95% CI: 4.43–7.96) diet is consistently associated with higher levels of sustainability in all areas assessed. In contrast, the Western diet shows a significant negative association with sustainability in all subcomponents assessed. Conclusions: Plant-based dietary patterns were shown to be associated with sustainable lifestyles, with the vegan diet having the greatest association, while the Western dietary pattern was inversely associated. Full article

This paper analyzes phytoplankton communities in the Eastern Tropical Pacific Ocean off Mexico (ETPOM) and the Southern Gulf of California (SGC) during the strong El Niño event of 2023/24. A multidisciplinary research cruise was conducted in the winter of 2024, during which high-resolution hydrographic data and water samples for phytoplankton cell determinations were collected at 33 sites. Additionally, satellite data were obtained to evaluate sea surface temperature and chlorophyll-a levels. A total of 269 phytoplankton species were identified, comprising one hundred and fifty diatoms, one hundred and twelve dinoflagellates, five silicoflagellates, one ciliate and one cyanobacteria. The dominant species included the diatom Pseudo-nitzschia pseudodelicatissima, the dinoflagellate Gyrodinium fusiforme, the silicoflagellate Octactis octonaria, and the ciliate Mesodinium rubrum. The cyanobacterium Trichodesmium hildebrandtii was also identified. In terms of total abundances, diatoms were the most prevalent, with 224,900 cells L⁻¹, followed by dinoflagellates at 104,520 cells L⁻¹, ciliates at 20,980 cells L⁻¹, cyanobacteria at 1760 cells L⁻¹, and silicoflagellates at 1500 cells L⁻¹. Notably, interesting differences emerged in species richness and abundance when comparing both regions. These results enhance our understanding of phytoplankton dynamics associated with strong El Niño events. The ETPOM remains a region that requires further monitoring through in situ observations. Full article

Modern power generation aims to maximize the extraction of thermal energy from fossil fuels to produce electricity. Combined cycle power plants, leaders in efficiency, sometimes require an additional steam generator to compensate for insufficient exhaust gas energy in the heat recovery steam generator (HRSG), leading to hybrid combined cycles. This study presents a comprehensive thermodynamic analysis of the hybrid combined cycle power plant located in the Valley of Mexico, operating under both full-load and partial-load conditions. The investigation begins with an energy analysis evaluating key performance parameters under real operating conditions, including the power generation, heat flow supply, thermal efficiency, fuel consumption rates, steam flow, and specific fuel consumption. Subsequently, the analysis examines the performance of the steam cycle using the β factor, which quantifies the relationship between heat flows in the steam generator and the HRSG, to maintain a constant steam flow. This evaluation aims to determine the potential utilization of exhaust gas residual energy for partial steam flow generation in the steam turbine. The study concludes with an exergy analysis to quantify the internal irreversibility flows within the system components and determine the overall exergy efficiency of the power plant. The results demonstrate that, under 100% load conditions, the enhanced utilization of exhaust gases from the HRSG leads to fuel savings of 33,903.36 tons annually and increases the exergy efficiency of the hybrid combined cycle power plant to 54.08%. Full article

Background: Breast-conserving surgery (BCS) is one of the major surgical advances in breast cancer treatment. This study evaluated the oncological outcomes of BCS in patients with non-metastatic breast cancer at a referral cancer center in a medium-resource country between 2013 and 2019. Methods: An observational, analytical, retrospective cohort study was conducted on patients with stage I–IIIC breast cancer treated at the Instituto Nacional de Cancerología (Bogotá, Colombia) from September 2013 to March 2019. Demographic data, tumor characteristics, treatment types, and survival outcomes were retrospectively collected. Results: A total of 409 patients were included. In 64.1% of cases, BCS was performed as the initial treatment and in 35.9%, after neoadjuvant chemotherapy (NACT). With a median follow-up of 85.2 months, tumor recurrence was documented in 9.04% of patients, local recurrence in 2.9%, regional in 2.2%, and distant in 5.6%. The identified risk factors for mortality were a locally advanced clinical stage (HR 5.13; p = 0.01), triple-negative subtype (HR 8.02; p < 0.01), and nodal involvement of more than four lymph nodes in the surgical specimen (HR 4.00; p < 0.01). Conclusions: Breast-conserving surgery is an oncologically safe procedure for patients with early and locally advanced breast cancer who respond to NACT. The time to recurrence and overall survival are determined by the clinical stage, axillary tumor burden, and biological subtype of the disease. Full article

As the demand for sustainable and environmentally friendly materials has increased, renewable resources have been explored for the development of biobased composites. Two biobased composite materials were developed from thermoplastic starch (TPS), short fibers from plantain pseudostems sheaths and the starch from the plantain pseudostem core, using twin-screw extrusion and compression molding. Based on the findings, there is evidence of a biobased composite material with reduced water absorption of up to 9.9%, keeping thermal stability at a degradation temperature between 300 and 306 °C and increasing tensile properties by over 506%, although hardness showed slight increases (4.6%). In addition, the capacity of the sheath to generate a water vapor barrier is highlighted by reducing the magnitude of losses in mechanical properties during storage for a period of 8 days. This study contributes to the use of agricultural residues to create sustainable products, offering a pathway toward reducing dependency on synthetic polymers and mitigating environmental impact. Full article

The spray pyrolysis deposition of nanostructured Pb_1−xSn_xSe alloy films, x = 0.0 to 1.0, from as-prepared Pb_1−xSn_xSe alloy colloids as the starting solution is reported. The colloidal dispersions were prepared by dissolving selenium in an amine–thiol mixture, reacted with the Sn and Pb precursors in propylene glycol, and subsequently sprayed onto glass substrates at 300 °C. Structural characterization indicated the formation of the alloyed rock-salt cubic phase for 0.0 ≤ x ≤ 0.75, oxidized Pb and Se phases produced during the deposition, and only orthorhombic SnSe for x = 1.0 with Se and SnSe₂ as impurities. Nanocrystalline films ranging from 16 to 16.5 nm in size were obtained. The films displayed a shift in their optical structure and a non-monotonic variation in the band gap energy, first a decrease, reaching the minimum at x = 0.30 and a further increase in the Sn content. The decrease in the optical band gap resembles that of a topological insulator behavior. The morphology of the alloyed films confirmed the large nanocrystal formation by self-assembly processes in both the PbSe and SnSe phases and segregated PbSnSe platelets for x ≥ 0.30. Seebeck coefficient revealed that a typical semiconductor behavior dominated by bipolar transport, and p-type conductivity, but only for x = 0.0 n-type conductivity was exhibited. The maximal Seebeck coefficient magnitude behaved similarly to the band gap energy, evidencing the influence of energy band structure and the topological character. Full article

This study analyzed the lead concentrations in fruit grown near tailings dams of a mine in Zacatecas (Mexico) using electrochemical techniques. A 3 × 4 factorial design, with three levels of apple tree distance (low, medium, and high) and four levels of apple tree part (stem, leaf, pulp, and peel), was performed to predict the pathway for contamination (foliar or radicular). Samples of each apple tree part, soil, and irrigation water were collected. The lead concentrations were determined by anodic stripping voltammetry. The results showed lead concentrations of 172 ppm and 0.012 ppm for the soil and irrigation water, which were discarded as sources of contamination since they were below the allowable limits by the Mexican standards (400 ppm and 2 ppm, respectively). However, lead concentrations in the stem and leaf ranged from 6.6 ppm to 30.7 ppm, and pulp and peel exceeded 300 times the allowable limit by the Codex Alimentarius (0.1 ppm). The apple tree part was a significant factor in the experimental design. Hence, it was predicted that the pathway for contamination is by foliar absorption. The fruit is highly contaminated by its proximity to the mine. Therefore, mitigation actions must be performed to avoid health risks for the consumers of this fruit. Full article

Lithium is a metal with a highly promising outlook for future global demand. Its industrial processing relies on two primary methods: production from brines through solar evaporation ponds and production from rock sources via flotation, roasting, and subsequent leaching. Chile is currently the world’s second-largest producer of lithium, surpassed only by Australia. However, Chile’s lithium production process is significantly advantaged by the exceptionally high lithium concentration in the Salar de Atacama—the highest in the world—and the region’s high solar radiation, which enables the most cost-effective solar evaporation process globally. Despite these comparative advantages, Chile’s lithium production has stagnated in recent years. This stagnation can be attributed to the need for more flexible legislation surrounding the lithium industry or an increase in the number of CEOLs (Lithium Exploitation Contracts) to regain its position as the leading global producer of lithium. Furthermore, increased investment in national universities and research centers is essential to foster the development and implementation of new, clean technologies for future projects. By addressing these challenges, Chile has the potential to solidify its role as a key player in the global lithium market while promoting sustainable industrial practices. Full article