Global Challenges最新文献

Dry eye disease (DED), a multifactorial ocular surface disorder characterized by tear film instability, is pathologically linked to oxidative damage. The accumulation of reactive oxygen species (ROS) across ocular tissues not only directly damages nucleic acids, proteins, and lipids, but also functions as an upstream driver of inflammation and tear hyperosmolarity, collectively disrupting cellular homeostasis. This review comprehensively delineates the mechanistic interplay between oxidative stress (OS) and DED pathogenesis, synthesizing evidence on enzymatic/ nonenzymatic antioxidant alterations in samples of corneal, lacrimal, conjunctival, meibomian gland, and tear tissues, alongside quantitative profiling of OS biomarkers, such as 4-hydroxynonenal (4HNE), malondialdehyde (MDA), 8-hydroxy-2′-deoxyguanosine (8-OHdG), and 3-nitrotyrosine (3-NT). Furthermore, the therapeutic mechanisms of clinically approved and investigational antioxidants, including SKQ1, rebamipide, mitoquinone, elamipretide, lactoferrin, nanozymes, graphene quantum dots, tetrahedral frame of nucleic acids, and Chinese medicine monomers are critically evaluated. With the changes in the modern social environment and lifestyle, the influence of OS on DED is gradually expanding. Antioxidant-based interventions are poised to become cornerstone components of multimodal DED management strategies.

Porous geopolymer materials can be used in various fields such as thermal insulation, filtration, catalyst, and building materials. In this study, open porous geopolymer-based cordierite materials are produced due to the porous structure, temperature resistance, and easy and low-cost applications of geopolymer structures, which are oxide ceramic materials that can act as natural catalysts for emission treatment of diesel engines. For the composition of cordierite, waste boron clay, metakaolin, fly ash, and magnesium carbonate are used, while keeping the geopolymerization temperature constant, sodium silicate, sodium hydroxide, polypropylene, and glass fiber, hydrogen peroxide are used to create an alkaline environment. These materials are tested in a 4-stroke 4-cylinder diesel engine's exhaust system at 50, 75, and 100 Nm engine torques and 1500, 1700, and 1900 rpm engine speeds. The use of open-cell geopolymer materials reduces CO emissions by 66%, NOx emissions by 25% and HC emissions by 68%. The open-cell geopolymer materials are found to be effective in treating over 95% of particulate matter. The chemical and microstructures of the obtained open-cell geopolymer structures are investigated. It is concluded that the developed products are useful tools for the emission treatments of diesel engines considering the oxidizing and filtering effects of the materials.

The direct utilization of metals from electronic waste (e-waste) in catalysis is a barely explored concept that, however, should be feasible for reactions where the catalytically active species can be formed in situ from the e-waste metal pieces. This approach circumvents any capture or isolation of particular metals, thus saving additional treatments (extractions, neutralization, separations, washings, …) and valorizing the e-waste in its own. Here, it is shown that a metallic contact (≈1 mg) of a computer´s random-access memory (RAM) catalyzes a variety of organic reactions in high yields. For instance, one RAM contact catalyzes the one-pot esterification-hydration reaction between acyl chlorides, propargyl alcohols, and water, at room temperature in 93–99% yields with turnover frequencies >0.5 million per hour. In this way, >50 kg of organic products could be prepared with just the RAM contacts discarded per year in the Institute´s recycling bin. These results open the way to directly use e-waste in catalysis for organic synthesis.

Urban wastewater treatment plants (WWTPs) generate sewage sludge, which retains ≈95% of the microplastics (MPs) processed in wastewater. The literature describes sewage sludges with MP concentrations ranging between 400 and 170,000 particles kg⁻¹ (dry weight) and when this sludge is applied to land, MPs spread into the environment. As a possible treatment for sewage sludge, this study aims to evaluate the effect of gamma-rays on the degradation of sludge MPs. The MPs utilized in the experiments are obtained from secondary sewage sludge provided by a municipal treatment facility and they are physic-chemically characterized (size, shape, composition). MPs are exposed to gamma radiation (γ-irradiation) at different time intervals and total doses to study the response process in sewage sludge. In particular, they are treated with γ-irradiation using cobalt-60 (⁶⁰Co) at doses ranging from 0 to 116 kGy. In this study, MP degradation can be achieved with a maximum degradation percentage of almost 70%. Concerning the specific degradation, research results show that both MP forms exhibit the same 35% degradation rate. This study not only advances the knowledge of how γ-irradiation affects MPs, but it also opens a new approach to fight against the global problem of environmental MPs.

In this study, the photo/electrocatalytic and electrochemical properties of the composite structure formed by coating silver sulfide (Ag₂S) and polyaniline (PANI) on titanium nanotubes are investigated. Titanium nanotubes (TiO₂ NTs) are synthesized on the surface of titanium (Ti) sheets using the anodization method. Ag₂S is deposited on the surface of TiO₂ NTs through the successive ionic layer adsorption and reaction (SILAR) method, while PANI is coated via the chemical oxidative polymerization technique. SEM-EDS, XRD, FTIR, and electrochemical measurements are used to characterize the prepared nanotubes. The corrosion inhibitor performance of TiO₂ NTs is investigated by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDS) measurements. EIS measurements showed that the PANI layer decreased the resistance of the photoanodes, while the Ag₂S coating increased the resistance compared to PANI. It is determined that the semicircles in the Nyquist curves drawn using EIS measurements are formed due to the Warburg resistance in the low-frequency region and the high-frequency region caused by the charge transfer resistance. Corrosion parameters are measured using Tafel fitting curves. Overall, TiO₂ NTs grown by anodization effectively prevented the corrosion of the Ti photoelectrode, and the corrosion rate is calculated at 0.013 mm/year (mpy). In electrocatalytic (EC), photocatalytic (PC), and photoelectrocatalytic (PEC) activity experiments, PANI/Ag₂S/TiO₂ NT photoelectrode removed 13.775%, 37.71%, and 61.075% of methylene blue (MB) within 120 min under UV light irradiation.

Hydrogen is promising as an innovative energy vector beyond its conventional role and receiving international identification as a feasible fuel source. This review provides a concise examination of current advances in hydrogen production techniques employing renewable and conventional energy sources, as well as important difficulties in hydrogen production. Wind and solar are the two most promising sustainable energy sources for hydrogen manufacturing. The hydrogen production from renewable sources generated from undeveloped or other waste flows increases the affordability and flexibility of semi-centralized and distributed reforming while emitting no net or fewer greenhouse gases. Water electrolysis apparatus powered by wind energy or off-grid solar can also used in distant places away from the framework. Every hydrogen-producing technology presents technological obstacles. These obstacles include conversion efficiency, feedstock type, and the requirement to safely integrate the production of hydrogen systems with storage and purification technology.

This study investigates the groundwater potential zones in the Ziway Lake watershed of Ethiopia's rift valley using a GIS-based multi-criteria decision analysis within the Analytical Hierarchy Process (AHP). Environmental factors, including recharge, lithology, elevation, lineament density, and drainage density, are analyzed. The soil and water assessment tool (SWAT) model is applied to estimate groundwater recharge for the watershed. The performance of the SWAT model, evaluated based on observed streamflow at Katar and Meki stations, demonstrates good performance during the calibration and validation phases. The watershed's groundwater potential is classified as Very low (18.01%), Low (17.62%), Moderate (12.05%), High (28.34%), and Very High (23.98%). Groundwater potential zones are integrated with drinking water quality index zones using GIS, showing that (39.72%) of very high and high potential areas have good to excellent water quality. Results show that over half of the watershed has moderate to very high groundwater potential, identifying critical areas for sustainable water management. The findings provide useful guidance for identifying key areas for groundwater exploration and conservation, offering a practical approach that can be applied to other regions to ensure sustainable management.

The gradual ascent strategy, an effective measure to prevent acute mountain sickness by enabling the body to adapt to high–altitude hypoxia, has an unclear mechanism. This study explores controlled ascent rates' effects on autophagy, oxidative stress, inflammation, and lung injury in rats exposed to high-altitude hypoxia, hypothesizing that gradual ascent can activate autophagy, reduce oxidative stress and inflammation, and improve lung injury. 70 male Sprague-Dawley rats are divided into seven groups, including a normal control group and high-altitude hypoxia for 24, 72, and 120 h, with or without controlled ascent rates. Lung tissues are analyzed for the wet-to-dry weight ratio, histopathology, inflammatory cytokines, oxidative stress markers, and autophagy-related protein expression. Results show that controlled ascent rates reduced lung injury, oxidative stress, and inflammation in rats exposed to high-altitude hypoxia while increasing autophagy. This study indicates that gradual ascent can be an effective strategy for reducing lung injury in high-altitude areas by regulating autophagy and reducing oxidative stress and inflammation.

Metal-free g-C₃N₄ (graphitic carbon nitride) is a promising candidate for the next-generation visible light-responsive photocatalyst; however, the recombination and transfer of the photogenerated charge carriers restrict its photocatalytic performances. The exfoliated g-C₃N₄ sensitized with brominated perylenediimide (dBrPDI) and perylene tetraester (dBrPTE) enhances the photocatalytic performance due to improved charge separation, light absorption, charge transfer and, thereby, overall efficiency in pollutant degradation. The g-C₃N₄/dBrPTE hybrid composite exhibits the fastest photocatalytic degradation against rhodamine B (RhB) pollutants. The g-C₃N₄/dBrPTE hybrid composite degrades RhB with a 2.34-fold improvement over pure g-C₃N₄, while the g-C₃N₄/dBrPDI hybrid composite degrades with a 1.56-fold increase over pure g-C₃N₄. The g-C3N4/dBrPDI hybrid composite shows the highest photocatalytic efficiency against methyl orange (MO) pollutants. The g-C₃N₄/dBrPDI hybrid composite degrades MO with a 2.25-fold improvement over pure g-C₃N₄, while the g-C₃N₄/dBrPTE hybrid composite degrades with a 1.8-fold increase over pure g-C₃N₄. Unlike MO and RhB, the perylene dye sensitization does not enhance the photocatalytic degradation of 2,4-dichloro phenoxy acetic acid (2,4-D) and no sustained increase in efficiency is not observed. Overall, these results suggest that photocatalytic efficiency depends not only on the sensitized photocatalyst material but also on the interaction between the sensitized photocatalyst and the chemical and ionic properties of the pollutants in the aquatic media.