Global Challenges最新文献

A study conducted in Egypt evaluated the effectiveness of chemical and microbial agents in enhancing sweet pepper (Capsicum annuum var. annuum) defenses against major pests Aphis gossypii and Thrips tabaci and their natural predators, Chrysoperla carnea and Orius insidiosus. Five foliar treatments were tested under greenhouse conditions during the 2022 and 2023 growing seasons: salicylic acid (SA), potassium phosphite (PK), effective microorganisms (EMs), insecticide imidacloprid (IMI), and a water-sprayed untreated check (control). In addition to monitoring pest and predator populations, several biochemical parameters were assessed in pepper leaves, including total chlorophyll, macronutrients (N, P, K), phenolic compounds, and total protein content. All treatments improved plant growth and enhanced physiological traits, promoting both vegetative development and fruit productivity. Salicylic acid was the most effective treatment, significantly increasing chlorophyll levels, nutrient uptake, phenolic content, and total proteins. Moreover, all agents led to a marked reduction in pest populations while preserving predator abundance, indicating strong plant defense activation and selectivity toward beneficial insects. These findings demonstrate that the tested agents, particularly salicylic acid, can serve as practical and sustainable alternatives to synthetic insecticides and are suitable for integration into environmentally friendly pest management strategies and Integrated Pest Management (IPM) programs.

Control of odor-active compounds in polymers is fundamental for both recycling and the circular economy. Among deodorization strategies for post-consumer plastics, washing plays a central role. This study focuses on the odor characterization of rigid polypropylene (PP) waste and the evaluation of different washing procedures for deodorization efficiency. Three washing regimes are tested, varying in temperature (25°C vs. 80°C) and medium (water vs. caustic soda with detergent). The resulting sample sets are classified as unwashed (UW), room temperature washed (RT), hot water washed (HW), and detergent washed (DW). Odor profiles are determined by descriptive sensory analysis, while odor-active compounds are identified using gas chromatography-olfactometry (GC-O). Ranking of odor contributions is performed through odor extract dilution analysis (OEDA). A total of 32 odorants are detected, of which 30 are identified via 2D gas chromatography–mass spectrometry/olfactometry (2D-GC-MS/O). Washed material exhibits flowery and soapy impressions, whereas unwashed PP is characterized by moldy notes. Hedonic ratings are lowest for UW, with statistically significant improvement observed in DW. Intensity ratings do not differ significantly across UW, RT, and DW, ranging from 7.5 to 5.5 on a 0–10 scale. These findings link chemo-sensory methods with odorant removal efficiency, advancing deodorization approaches for plastics.

The replacement of Portland clinker with supplementary cementitious materials is a key approach to reducing the embodied carbon content of concretes. In this context, a widely studied family is the "limestone calcined clay cements, LC³." Within this eco-friendly family of materials, one composition is gaining popularity, LC³-50, a blend of ~50% of Portland clinker, 30% of activated clay, 15% of limestone and 5% of gypsum. This interest is due to a ~40% reduction of CO₂ emissions compared to Portland clinker, together with high compressive strengths after 7 days and very good durability against chloride and sulfate attacks. However, limitations still exist, such as low strengths at 1 day, workability loss during the first 2 h and reduced carbonation resistance. These drawbacks are being overcome with tailored admixtures and curing approaches. Here, after introducing low-carbon cements, pozzolans, and pozzolanic reactions, as well as phyllosilicate minerals, attention is given to recent progress in thermal and mechanical, aka mechanochemical, activations. Then, general correlations are established to assist in predicting compressive strength. This work concludes by highlighting the challenges that must be overcome for the widespread adoption of these classic rocks processed to yield advanced materials with the highest possible pozzolanic reactivity.

The connectivity and interdependence of our world and its inhabitants’ health have come under increasing focus. Elucidation of the common and interdependent mechanisms of health and disease requires approaches that facilitate understanding of complex systems behavior and probing of both individual and collective system parameters. To this end, multiscale physical and computational modeling offers a particularly powerful tool to predict behavior over vast time and length scales. Other novel technologies, e.g., rapid isolation nanotechnology developed to analyze nanoscale small extracellular vesicles in ocular tears, enable tracking of “fingerprints” from diseases as diverse as ocular to neurodegenerative (e.g., dementia) and cancer. In the future, it will be possible to track the health and disease of ecosystems and their inhabitants, using geospatial and epidemiological approaches, as well as novel biotechnologies, to prevent and mitigate disease processes and enhance well-being. These concepts are applied by way of an exemplary approach to understand and address the impact of toxic, recalcitrant manmade chemicals (i.e., PFAS) on the health of ecosystems and their diverse inhabitants. Such convergent efforts will be necessary and a priority for solving the complex problems threatening the health of our planet and its inhabitants.

Bisphenol A (BPA), a widely used industrial chemical, persists in aquatic environments and poses serious endocrine-disrupting risks to ecosystems and human health. This study presents a highly sensitive, selective electrochemical sensor using lanthanum stannate (La₂Sn₂O₇), a rare-earth stannate, engineered for efficient BPA detection in real water matrices. The La₂Sn₂O₇ nanostructure was synthesized and employed as an electrocatalytic modifier, offering unique physicochemical properties that facilitate accelerated electron transfer kinetics and abundant electroactive surface sites. Systematic electrochemical characterizations confirmed the material's superior catalytic performance, attributable to its synergistic structural and electronic attributes. Under optimized pH and operating conditions, the La₂Sn₂O₇-modified electrode demonstrated exceptional analytical capability, exhibiting an ultra-low detection limit of 1.4 nM and a broad linear dynamic range spanning 0.001‒425.8 µM. These findings indicate remarkable sensitivity and reliability in quantifying trace BPA levels. Moreover, the sensor demonstrated excellent analytical recovery and reproducibility in diverse real-water samples, including lake, river, tap, and plastic-bottled water, underscoring its robustness and practical applicability in complex environmental matrices. La₂Sn₂O₇ shows strong promise as an electrocatalyst, enabling real-time BPA detection for enhanced environmental monitoring and public health protection in the field.

Financial stability is essential for the sustainable operation of wastewater treatment plants (WWTPs), as they require substantial resources but generate minimal revenue. In Mexico, a lack of funding resources and supporting policies has resulted in inefficient treatment and extensive surface water degradation. This work examines the positive impacts of treated sewage-operated irrigation ponds equipped with floating photovoltaics on the WWTP's economic viability in central Mexico. These ponds will provide water for irrigation expansion in rainfed cornlands, and the harvested solar energy will be exported to the national grid to independently generate income. The turnover will cover capital and operational expenditures of WWTPs, irrigation ponds, FPV, and energy for irrigation. The proposal's performance is evaluated through techno-economic and Water-Energy-Food Nexus assessments on municipal level. It is projected that by in-situ recycling 35% of generated sewage, local corn growers could benefit from an additional 45 320 hectares (223%) of irrigated cornland, over 5 46 000 tons (132%) of corn grain production, and 139% more sales revenue. The overall power capacity of FPV units could reach 834 MW, and 1796 GWh of clean energy could be harvested annually. This example demonstrates the value proposition of irrigation ponds and FPVs on the sustainability of existing WWTPs globally.

Carbon nitride quantum dots (CNQDs) are emerging as versatile photocatalytic materials with promising applications in biomedicine and environmental remediation. In this study, we synthesized pristine and sulfur-doped CNQDs via a hydrothermal method, and characterized them using transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and UV–vis absorption spectroscopy. For the first time, the quantum yields of superoxide and singlet oxygen generation were measured for CNQDs. Sulfur doping was found to significantly enhance superoxide generation while concurrently suppressing singlet oxygen production, offering a powerful mechanism for tailoring reactive oxygen species (ROS) output. In addition, all CNQD samples produced hydrogen peroxide and hydroxyl radicals. The ability of these nanomaterials to produce multiple ROS types underscores their potential as hypoxia-resistant photosensitizers (PSs) for photodynamic therapy (PDT) and as efficient photocatalysts for pollutant degradation.

This study explores a dual-use CO₂-breathing plasma thruster capable of operating in very low Martian orbits (80–160 km), delivering electric propulsion and in situ oxygen generation. Experimental results demonstrate a thrust of over 1 N at input powers ranging from 0.1 to 1 kW across varying discharge frequencies. Optical emission spectroscopy reveals strong emission at 777.1 nm corresponding to atomic oxygen, along with spectral features of CO and CO₂, confirming the effective dissociation of CO₂ within the plasma. These findings support the viability of propulsion systems as multifunctional platforms for future Mars missions, enabling both aerial/ground mobility and human habitats without stored propellant gas.

Research in global health is often framed as centering health equity. However, research and programmatic partnerships are often relationships between institutions and researchers in high-income countries (HICs), and researchers and actors in low- and middle-income countries (LMICs), including many countries in Sub-Saharan Africa (SSA). Such relationships are rife with power dynamics that require thoughtful attention and solutions. Feminist research methods, including perspectives from intersectional and African feminist thinkers, as well as participatory approaches, may offer a means of engaging with power inequities and disrupting often taken-for-granted assumptions in the SSA context. Such epistemological perspectives and methods not only disrupt “traditional” research relationships and challenge unexamined assumptions about knowledge but are also driven by the lived experiences of health disparities in specific, formerly colonized contexts and can therefore lead to context-specific or localized solutions to complex health inequities. This paper explores how these specific feminist research perspectives and methods can challenge power dynamics that are often embedded in global health research and interventions in SSA.

Copper-based oxides, including Cu₂O, CuO, CuBi₂O₄, CuFeO₂ and CuFe₂O₄ have emerged as promising photocathode materials for solar-driven photoelectrochemical (PEC) reduction reactions such as hydrogen evolution (HER), carbon dioxide reduction (CO₂RR), and nitrogen reduction (NRR). Their appeal lies in the combination of their earth-abundance, low toxicity, and suitable optoelectronic properties. However, the practical deployment of these materials is hindered by their intrinsic instability under operating conditions, primarily due to photocorrosion, interfacial charge recombination, and limited carrier transport. This review provides a comprehensive overview of recent strategies developed to improve the stability of the most studied Cu-based photocathodes in relevant reported works. Specifically, seven key approaches are discussed: (i) optimization of electrical contact with the substrate, (ii) use of hole-selective layers, (iii) electron-extraction overlayers, (iv) protective coatings, (v) surface passivation strategies, (vi) integration of co-catalysts, and (vii) synergistic strategies. Particular emphasis is placed on how each strategy addresses specific degradation mechanisms, and how synergistic combinations can enable durable and efficient PEC operation. Finally, the present review outlines current challenges related to scalability, fabrication compatibility, and real-world durability, and highlights emerging directions in materials design and device integration. Unlike previous reviews that predominantly compare device efficiencies, this work places stability at its core, providing a strategy-oriented perspective on how Cu-based photocathodes can be made durable under operational conditions. By systematically connecting structure, interface, and function, this work aims to guide the development of robust Cu-based photocathodes for sustainable solar fuel production.