Search Results (413)

Bacterial contamination remains a challenge for multiple facets of modern life. While antibiotics are a primary tool for bacterial control, their overuse has accelerated the appearance of multidrug-resistant bacteria and raises global health concerns. In swine, semen is stored at 17 °C in extenders that contain antibiotics to prevent bacterial growth. Apart from the potential consequences for the female, the proliferation of bacteria in liquid-stored semen is associated with a decline in sperm quality, ultimately reducing farrowing rates and litter sizes. With the aim of reducing the use of antibiotics while keeping bacterial growth under control, we herein investigated whether metal ions could exert an antimicrobial effect without impairing sperm quality. Separate metal ions (Ag, silver sulfadiazine; Al, aluminum chloride; Zn, zinc chloride; and Cu, and cooper chloride) were added at different concentrations (100 μM, 300 μM, 500 μM, 1 mM, and 10 mM) to seminal doses, which were stored at 17 °C for 48 h. Motility, viability, and the intracellular levels of reactive oxygen species (ROS) were tested to determine their effects on sperm quality maintenance. In addition, ions were added to bacterial strains and to extended seminal samples to assess the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Results showed that, although silver sulfadiazine exerted an antimicrobial effect at all the concentrations tested, it also affected sperm quality negatively (p < 0.05). In contrast, aluminum chloride did not impair sperm quality but failed to inhibit bacterial growth at any of the tested concentrations (p > 0.05). Finally, 1 mM concentrations of copper and zinc chloride reduced microbial growth (p < 0.05) without affecting sperm quality. In spite of this, the inhibition of bacterial growth was not complete, thus suggesting that these two ions could contribute to reducing bacterial growth but should be combined with other strategies, such as a lower storage temperature and a decreased concentration of antibiotics. Further research is warranted to address whether copper and zinc chloride could have a synergistic effect when added together. Full article

Background: Effective cetylpyridinium chloride (CPC)-based mouthwashes critically depend on maintaining maximum levels of bioavailable CPC to deliver optimum antimicrobial benefits. While this is traditionally assessed using cellulose-based methods, from economic and efficiency perspectives, there remains a need to identify other potential methods of assessing bioavailable CPC. Here, we explored whether quaternary ammonium compound (QAC) test strips are sensitive to CPC-based formulations, and if so, whether there might exist a possible correlation with glycolysis outcomes. Methods: Quantitative color parameters were obtained using spectrophotometric assessments of QAC test strips immersed in simple CPC solutions and eight commercial CPC-based mouthwashes available in the USA. Then, using our established glycolysis model, we assessed the glycolytic response of both the simple CPC solutions and commercial CPC-based mouthwashes, and compared these data sets. Results: Significant differences (p < 0.05) among the CPC simple solutions were found. Importantly, spectrophotometric assessments and glycolysis trials produced good correlations. Evaluations of the commercial mouthwashes further underlined this correlation, even though those that comprise zinc salts may impact QAC-based color. Conclusions: Based on these results, we believe the use of QAC test strips provides an attractive option to formulators and brands specializing in the development and/or testing of CPC-based oral care formulations. Full article

Background: Colorectal cancer (CRC) is a malignancy that ranks among the top three in terms of both global mortality and incidence. Although numerous studies have demonstrated that gut microbes are implicated in CRC pathogenesis, the precise mechanisms underlying host–microbiota metabolic crosstalk remain poorly understood. Objective: This study aims to identify and delineate key co-metabolites and their associated metabolic pathways that modulate the biomass of CRC-related gut bacteria within healthy individuals, through the construction of host–gut microbiota co-metabolic network models. We seek to elucidate the underlying mechanisms of metabolic interplay between the host and CRC-related gut microbiota, thereby offering novel perspectives on the microbial involvement in the initiation and progression of CRC. Methods: We coupled a colon tissue-specific host Genome-Scale Metabolic Model (GEM), which utilized transcriptomic data from healthy human colon tissues, with 12 CRC-associated pro-/anti-carcinogenic gut bacterial GEMs to construct a co-metabolic network. Through a comparative analysis of the network structure and systemic methods (including Flux Sampling and metabolic difference analysis), we simulated scenarios of constrained host co-metabolite supply. Finally, metabolic subsystem enrichment analysis was employed to elucidate the specific molecular mechanisms by which key co-metabolites affect microbial function. Results: The 17 key co-metabolites identified include chloride ions, zinc ions, and acetate. Among these, thirteen metabolites (e.g., ferric iron, succinate, and acetate) were confirmed by literature to be associated with CRC. All 17 key co-metabolites were found to significantly modulate the biomass of CRC-associated gut bacteria. These regulatory effects primarily influence microbial function through core pathways such as glycerophospholipid metabolism and folate metabolism. Conclusion: This research provides a systemic perspective for elucidating the mechanisms of host–gut microbiota metabolic interplay in CRC, thereby complementing the existing theoretical framework concerning microbial regulation by the host genetic background. Full article

Functional properties of coastal halophytes are important for development of salt-tolerant cash crop cultures. The study of salt tolerance in coastal dune-building grass Leymus arenarius holds significant importance for its application in land reclamation, soil stabilization, and enhancing crop resilience to salinity stress. We used two accessions (LA1 and LA2) of L. arenarius to compare effects of salinity caused by NaCl and NaNO₃ on growth, ion accumulation and mineral nutrition in controlled conditions. L. arenarius plants exhibited high tolerance to sodium salts, with distinct effects on growth and development observed between chloride and nitrate treatments. While both salts negatively impacted root biomass, nitrate treatment (50–100 mmol L⁻¹) increased leaf number and biomass in LA2 plants, whereas chloride treatment decreased tiller and leaf sheath biomass. Despite individual variations, salinity treatments showed comparable effects on traits like tiller and leaf count, as well as leaf blade and sheath biomass. Salinity increased water content in leaf blades, sheaths, and roots, with LA2 plants showing the most pronounced effects. Chlorophyll a fluorescence measurements indicated a positive impact of NaNO₃ treatment on photosynthesis at intermediate salt concentrations, but a decrease at high salinity, particularly in LA2 plants. The accumulation capacity for Na⁺ in nitrate-treated plants reached 30 and 20 g kg⁻¹ in leaves and roots, respectively. In contrast, the accumulation capacity in chloride-treated plants was significantly lower, approximately 10 g kg⁻¹, in both leaves and roots. Both treatments increased nitrogen, phosphorus, and manganese concentrations in leaves and roots, with varying effects on calcium, magnesium, iron, zinc, and copper concentrations depending on the type of salt and tissue. These findings highlight the potential of L. arenarius for restoring saline and nitrogen-contaminated environments and position it as a valuable model for advancing research on salt tolerance mechanisms to improve cereal crop resilience. Full article

To reduce CO₂ emissions into the environment, the automotive sector uses microalloyed structural steels coated with electrophoretic paint in various components, such as the chassis, to reduce weight and increase corrosion resistance. AHSSs are coated with electrophoretic paint (E-coat). Still, to improve adhesion, they undergo a pretreatment, such as zinc phosphate or zirconium oxide. This research will analyze the effects and behavior of these coatings during corrosion on a complex-phase (CP) 780 AHSS using different electrochemical techniques, including cyclic potentiodynamic polarization (CPP), electrochemical noise (EN), and electrochemical impedance spectroscopy (EIS). The CP 780 AHSS was immersed in a 3.5 wt. % sodium chloride solution. Results show that AHSS CP 780 presented a mixed corrosion mechanism due to the heterogeneity of the surface of the zinc phosphate and zirconium oxide pretreatments. On the other hand, the samples with an E-coat paint coating and pretreatment (Zn₃(PO₄)₂/E-coat and ZrO₂/E-coat) have the lowest current densities with values of 6.44 × 10⁻¹¹ 1.02 × 10⁻⁹ A/cm² and also do not show a tendency towards localized corrosion or negative hysteresis. Full article

This study evaluates an integrated approach for recovering lead and silver from lead cake through chlorination roasting followed by acid leaching. The lead cake originates from sulfuric acid leaching of zinc ferrite residues obtained during the hydrometallurgical processing of zinc calcine. The effects of roasting temperature, lead cake-to-NaCl mass ratio, and roasting duration on metal recovery were systematically examined to determine optimal process conditions. Based on the experimental results, roasting at 550 °C for 1.5 h with a lead cake-to-NaCl mass ratio of 1:3, followed by leaching in 1 M HCl, was selected as a representative and sufficiently effective condition for the combined process. Under these conditions, nearly complete dissolution of Pb and Ag was achieved, reducing their contents in the final solid residue to 0.90% and 0.0027%, respectively. Compared to direct chloride leaching, the combined process provided higher extraction efficiencies (Pb 98.67%, Ag 98.09%) and a lower final residue mass (34% vs. 45%). The roasting step enables the solid-state conversion of PbSO₄ into highly soluble chloride phases (PbCl₂ and Pb(OH)Cl), while ZnFe₂O₄, Fe₂O₃ and SiO₂ remain stable and form the inert matrix of the residue. Acid leaching at a lower solid-to-liquid ratio (1:10) ensures near-complete dissolution of Pb and Ag, whereas aqueous leaching at a high ratio (1:100) results in incomplete Pb removal. The compliance leaching test (EN 12457-2) confirmed that the residue produced after the optimized two-step treatment meets the EU criteria for inert waste. Overall, the proposed combined process enhances Pb and Ag recovery, minimizes environmental risk, and offers a technically robust and sustainable route for treating lead-containing industrial residues. Full article

Worldwide, carbon fiber (CF) demand has been rising over the last decade, which contrasts with the fact that up to 30–50% of composite materials in aircraft production are scrapped. This situation highlights the increasing need for recycling methods to reduce fabrication costs and global warming potential. Emerging technologies focus on recovering long CFs, as they represent the most valuable form but are also the most difficult to reclaim using conventional recycling methods. Hydrothermal treatments offer a promising alternative to valorize this waste by decomposing the polymer matrix under subcritical and supercritical conditions without significantly damaging the fibers. Water, isopropanol, and mixtures of water/isopropanol or water/acetone were tested as solvents, with and without the addition of zinc chloride (ZnCl₂) as a homogeneous catalyst. The influence of temperature, pressure, and solvent composition on resin degradation was evaluated. In this work, degradation rates of up to 92% were achieved at 415 °C, 233 bar, 120 min, 5 wt.% IPA, and ZnCl₂ 0.1 M. It should be noted that ZnCl₂ caused reactor corrosion. Furthermore, the recovered fibers retained their morphology, including the sizing layer, and showed mechanical properties similar to the original material, while a small H₂-rich gaseous fraction was generated as a byproduct of the hydrothermal degradation. Using water–isopropanol solutions resulted in the reactor being significantly cleaner than when using water alone, which can be advantageous for future scale-up and for reducing maintenance requirements. These results confirm the potential of hydrothermal processing as an efficient and selective method for the recycling and valorization of carbon-fiber-reinforced composites from the aeronautical industry. Full article

This study investigates the atmospheric corrosion behavior of zinc in tropical marine environments affected by hydrogen sulfide (H₂S), particularly from the decomposition of stranded Sargassum algae. Four exposure sites in Martinique with varying levels of H₂S and marine chlorides were selected. Gravimetric analysis showed that zinc thickness loss reached up to 45 µm after one year at the most impacted site (Frégate Est), compared to only 3–10 µm at less contaminated locations. This degradation level classifies the site as “extremely corrosive” according to ISO 9223. Electrochemical impedance spectroscopy (EIS) and linear polarization measurements revealed distinct corrosion behaviors. After 12 months of exposure, the polarization resistance and corrosion current density reached R_p = 916 Ω·cm² and I_corr = 28 µA·cm² at the Frégate Est site and R_p = 1835 Ω·cm² and I_corr = 6 µA·cm² at the Vauclin site. In H₂S-poor environments (Diamant, Vert-Pré, Vauclin), corrosion resistance increased over time due to the formation of protective layers such as hydrozincite and simonkolleite. In contrast, H₂S-rich environments favored the formation of sulfur-based compounds like elemental sulfur and zinc sulfide (ZnS), which exhibit poor protective properties and result in lower polarization resistance and higher corrosion current densities. Polarization curves confirmed a general decrease in anodic and cathodic currents over time, with less significant improvements in passivation at H₂S-impacted sites. The corrosion mechanism is influenced by both pollutant type and exposure duration. Overall, this study highlights the synergistic effect of H₂S and chlorides on accelerating zinc corrosion and underscores the need for adapted protection strategies in tropical coastal zones affected by Sargassum proliferation. Full article

Intensive calcination, selection and metallurgical joint comprehensive utilization of solid waste blast furnace gas ash generated by a Chinese iron and steel plant. The main valuable elements in the gas ash are Fe, Pb, Zn, and C, with contents of 22.46%, 3.22%, 10.57%, and 27.02%, respectively. The iron minerals are mainly magnetite and hematite/limonite. Lead exists primarily in the form of lead vanadate and basic lead chloride. Zinc is associated with oxygen, sulfur, and iron in the form of zinc ferrite crystals. The effects of calcination temperature, calcination time, and reducing agent dosage on gasification and reduction indices were investigated. Results showed that using a gasification and reduction calcination–magnetic separation process with weak magnetism, at a calcination temperature of 1150 °C, with 20% anthracite as the reducing agent and a calcination time of 2 h, the volatilization rates of lead and zinc reached 96.70% and 98.26%, respectively. When the roasted ore was ground to a particle size of D₉₀ = 0.085 mm, high-quality iron concentrate with 65.61% iron grade and low lead and zinc contents of 0.08% and 0.17% was obtained, meeting the quality requirements for iron concentrate. The tailings from iron selection can be used as additives in cement and other construction materials. This integrated process combining pyrometallurgy and mineral processing enables the efficient and comprehensive utilization of blast furnace gas dust. Full article

Zn-based ternary deep eutectic solvents (TDESs) have attracted significant attention due to their good biodegradability, stability, and sustainability. In this work, TDESs composed of choline chloride:urea (ChCl:U) and zinc salts, ZnCl₂, Zn(CH₃COO)₂, and ZnSO₄ were synthesized and characterized by Fourier transform infrared (FTIR) spectroscopy and laser desorption ionization mass spectrometry (LDI MS). Their antibacterial activity against cariogenic Streptococcus species isolates was determined by microdilution assay, while their cytotoxic potential and effect on the intracellular reactive oxygen species (ROS) induction were analyzed on the MRC-5 fibroblast cell line by XTT, trypan blue, and DCF assays, respectively. FTIR confirmed that hydrogen bonds prevail in the molecular structure of ChCl:U:Zn salts, while LDI MS revealed the interactions between zinc salts and ChCl:U. The antibacterial TDES potential was high, especially against Streptococcus sanguinis, with ChCl:U:ZnCl₂ displaying the most promising effects (MICs 1.13–18.12 µg/mL). Cytotoxicity assessment showed that concentrations up to 100 µg/mL of all TDESs did not display significant cytotoxicity, while higher concentrations significantly reduced cell viability by increasing ROS production and cell membrane damage, outlining the safety window of up to 100 µg/mL. Strong antibacterial activity of low TDESs concentrations combined with their good biocompatibility highlights their potential as innovative candidates for biomedical application. Full article

The remediation of heavy metal-contaminated sediments is a significant environmental challenge. While cation effects are well studied, the influence of common co-existing anions on treatment efficiency remains poorly quantified. This study systematically investigates the effects of nitrate (NO₃⁻), chloride (Cl⁻), and sulfate (SO₄²⁻) ions on the flocculation and consolidation of copper (Cu)- and zinc (Zn)-contaminated sediments through settling column tests, turbidity measurements, and oedometer consolidation tests. Results demonstrated that NO₃⁻ achieved the highest flocculation efficiency, with a final settling height of 3.52 cm and a supernatant turbidity of 4.6 NTU, and the best consolidation performance, with a coefficient of 1.27 × 10⁻³ cm²/s. In contrast, SO₄²⁻ yielded the poorest outcomes. The superior performance of NO₃⁻ is attributed to its low charge density, which promotes the formation of denser flocs. These findings underscore that anion selection is a critical factor for optimizing sediment dewatering processes, suggesting that strategies favoring nitrate conditions can enhance the efficiency of techniques like pressure filtration and vacuum pre-compression. Full article

This study reports the synthesis of an activated nanoporous carbon material from Phyllanthus emblica (Amala)—a biomass material which is an eco-friendly, economical, and sustainable precursor used to prepare activated carbon using zinc chloride (ZnCl₂) activation at various temperatures (500–700 °C) under a nitrogen gas atmosphere. A sample that was carbonized at 700 °C (AmC_Z700) attained a high specific surface area of 1436 m² g⁻¹ and a total pore volume of 0.962 cm³ g⁻¹, and, when used in an electrode, showed excellent supercapacitance performance, attaining a high specific capacitance of 263 F g⁻¹ at a current density of 1 A g⁻¹, followed by 55% capacitance retention at 50 A g⁻¹. Additionally, the assembled symmetric supercapacitor cell, when operated at 1.2 V, delivered an energy density of 8.9 Wh kg⁻¹ at a power density of 300 W kg⁻¹ and exhibited an excellent cycle life of 95% after 10,000 successive charge/discharge cycles, demonstrating the substantial potential of Phyllanthus emblica seed-derived carbon materials for the creation of high-performance supercapacitors. Full article

Waste generated from agricultural activities is anticipated to increase in the future, especially in less developed countries, and this could cause environmental health risks if these wastes are not well managed. The anaerobic digestion (AD) by co-digesting organic waste is a technology used to produce biogas while utilizing biodigestate as a biofertilizer; however, AD requires a lot of water to be efficient, which could pose water challenges to arid areas. This study evaluated biogas production under semi-dry conditions by augmenting the process with a high-water content wild melon and determined the nutrient composition of the resultant biodigestate. Batch studies of AD were performed to evaluate methane potential of the different animal waste using an online and standardized Automatic Methane Potential Test System (AMPTS) II light for approximately 506 h (21 days) at 38 °C. The highest biomethane potential (BMP) determined for mono and co-substrate digestion was 29.5 NmL CH₄/g VS (CD) and 63.3 NmL CH₄/g VS (CMWM), respectively, which was calculated from AMPTS biomethane yield of 3166.2 NmL (CD) and 1480.6 NmL (CMWM). Water-displacement method was also used to compare biogas yield in wet and semi-dry AD. The results showed high biogas yield of 8480 mL for CM (mono-substrate) and 10,975 mL for CMCC in wet AD. Semi-dry AD was investigated by replacing water with a wild melon (WM), and the highest biogas production was 8000 mL from the CMCC combination augmented with WM. Generally, in wet AD, co-digestion was more effective in biogas production than mono-substrate AD. The biodigestate from different substrate combinations were also evaluated for nutrient composition using X-ray Fluorescence (XRF) analysis, and all the samples contained fair amount of essential nutrients such as calcium (Ca), phosphorus (P), potassium (K) and microelements such as chloride (Cl), magnesium (Mn), iron (Fe), zinc (Zn). This study successfully implemented semi-dry AD from co-digested animal wastes to produce biogas as an energy solution and biofertilizer for crop production, thereby creating a closed-loop system that supports a circular bioeconomy. In addition, the study confirmed that lowering the water content in the AD process is feasible without compromising substantial biogas production. This technology, when optimized and well implemented, could provide sustainable biogas production in areas with water scarcity, therefore making the biogas production process accessible to rural communities. Full article

Corrosion of steel structures remains a persistent challenge in construction, particularly in coastal and industrial environments where chloride-induced degradation accelerates structural failure. This study presents an eco-friendly approach to improve the corrosion protection of the steel by incorporating Lawsonia inermis (henna) leaf extract into zinc–aluminum silicate coatings. The henna extract was added at varying concentrations (0–12 wt%) to evaluate its influence on structure, adhesion, and electrochemical performance of the coating. Physicochemical characterizations including FTIR, XRD, XRF, and SEM revealed that a 5 wt% addition optimized pigment dispersion, resulting in a denser and more homogeneous coating microstructure. Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization tests after 35 days of immersion in 3.5 wt% NaCl solution demonstrated that this formulation achieved the highest impedance and polarization resistance, confirming enhanced corrosion resistance. The improvement was attributed to the dual action of the henna extract: (i) as a dispersant, promoting uniform Zn–Al pigment distribution and reducing porosity, and (ii) as a green corrosion inhibitor, forming an adsorbed protective film on the steel surface. This work highlights the potential of bio-derived additives to enhance the long-term durability of steel infrastructure and supports the development of sustainable protective materials for construction applications. Full article

The zinc complex of salicylaldehyde serine Schiff base (ZnL) was synthesized from serine, salicylaldehyde, and zinc diacetate and subsequently applied as a heat stabilizer in poly (vinyl chloride) (PVC). The structure of ZnL was determined using elemental analysis, crucible thermogravimetric method, infrared spectroscopy, thermogravimetric analysis and ¹H NMR spectra. The heat stability effect of ZnL for PVC was investigated using the Congo red and oven aging methods. The results indicated that PVC stabilized by ZnL exhibited a certain degree of original whiteness and long-term heat resistance. In contrast with PVC stabilized by ZnSt₂ and Ca/Zn, ZnL was found to be slightly inferior in terms of whiteness but superior in long-term heat resistance. It was observed that complexation of ZnL with CaSt₂ could enhance both the original whiteness and long-term heat resistance of PVC, while also alleviating the “zinc burning” phenomenon. In contrast, complexation with ZnSt₂ was found to promote “zinc burning” for PVC. Furthermore, the heat stability mechanism of ZnL for PVC was explored through experiments focusing on HCl absorption and active chlorine substitution. The results demonstrated that ZnL could replace active chlorine on the PVC molecule and absorb HCl gas. Finally, auxiliary heat stabilizers such as pentaerythritol (Pe), dibenzoyl methane (DBM), and epoxidized soybean oil (ESBO) were added to ZnL/CaSt₂ to evaluate their synergistic effects. It was found that ESBO in PVC exhibited the best synergistic effect with ZnL/CaSt₂ and was superior to those observed with DBM and Pe. When the ratio of ZnL/CaSt₂/ESBO was set at 0.6/2.4/0.9, PVC demonstrated the optimal thermal stability performance. Full article