Search Results (3,128)

Water quality assessment is crucial for the sustainable use and management of groundwater resources. This study was carried out in the irrigated plains of Vehari District, Punjab, Pakistan, to evaluate groundwater suitability for a managed aquifer recharge (MAR) project. Twenty groundwater samples were collected in June 2021 from an area of 1522 km² and analysed for major physicochemical parameters including electrical conductivity (EC), total dissolved solids (TDS), pH, turbidity, calcium (Ca), magnesium (Mg), chloride (Cl), alkalinity (Alk), bicarbonate (HCO₃⁻), hardness, potassium (K), sulphate (SO₄²⁻), sodium (Na), and nitrate (NO₃⁻). Water quality was assessed using WHO and PID standards, alongside derived hydrochemical indices such as sodium percentage (%Na), Kelly’s ratio (KR), sodium adsorption ratio (SAR), residual sodium carbonate (RSC), and the water quality index (WQI). The dataset was interpreted using geo-statistical, geospatial, multivariate, and correlation analyses. Cations and anion dominance followed the order Na⁺ > Ca²⁺ > Mg²⁺ > K⁺ and HCO₃⁻ > SO₄²⁻ > Cl⁻ > NO₃⁻. According to the WQI analysis, 35% of the water samples are classified as “poor,” half (50%) as “very poor,” and the remaining 15% as “unsuitable” for drinking purposes. However, irrigation suitability indices confirmed that groundwater is generally acceptable for agricultural use, though unfit for drinking. The outcomes of this study provide essential insights for groundwater management in the region, where the Punjab Irrigation Department (PID) has initiated a MAR project. Considering that the irrigation sector is the major groundwater consumer in the area, the compatibility of groundwater and surface water quality supports the implementation of MAR to enhance agricultural sustainability. Full article

This study developed a two-step conversion strategy for the efficient conversion of bamboo waste into 5-hydroxymethylfurfural (HMF). First, ultrasonic-assisted formic acid pretreatment was used at 80 °C for 3 h, removing approximately 83.7% of hemicellulose and 76.5% of lignin from the biomass, with a cellulose recovery of 93.5%. The ultrasonic step significantly enhanced the chemical action of formic acid through cavitation, allowing formic acid to penetrate deeper into the biomass, thereby more effectively removing hemicellulose and lignin. Subsequently, glucose was obtained through an enzymatic hydrolysis. In the second step of HMF preparation, citric acid in the hydrolysate was combined with ChCl to form an acidic deep eutectic solvent (DES), and metal chlorides were added as Lewis acid catalysts. Experiments results showed that when the ChCl–citric acid ratio was 2:1, and the Ca²⁺ concentration was 100 mM, an HMF yield of 51.9% was obtained at 220 °C for 1.5 h. This study provides an efficient, mild, and environmentally friendly method for the high-value valorization of waste bamboo. Full article

Background: Haemonchus contortus is a gastrointestinal nematode that affects small ruminants and exhibits widespread resistance to commercial anthelmintics. This has driven interest in natural compounds such as fatty acids and sterols; however, their biological relevance against resistant parasite strains remains insufficiently understood. Methods: The nematicidal potential of four fatty acids (palmitic, linoleic, pentadecanoic, and stearic acids) and two sterols (β-sitosterol and ergosterol), all of them commercially available in Mexico, was evaluated against infective L3 larvae of a benzimidazole-resistant H. contortus strain. In vitro larval mortality and migration inhibition assays were performed, and molecular docking analyses were conducted to explore interactions with the glutamate-gated chloride channel (GluCl) using AutoDock4. Statistical analyses were performed using ANOVA followed by Tukey’s post hoc test (p < 0.05). Results: Molecular docking indicated strong binding affinities of ergosterol and β-sitosterol to GluCl, comparable to that of ivermectin. In vitro assays showed that fatty acids, particularly linoleic acid, produced more pronounced effects on larval motility, suggesting predominantly nematostatic activity. No clear dose–response relationship was observed in migration assays, and in vitro mortality remained limited across treatments. Conclusions: The results highlight a disconnect between in silico binding affinity and in vitro biological activity, particularly in a drug-resistant H. contortus strain. Integrating in vitro bioassays with computational approaches provides valuable mechanistic insight but also underscores the limitations of affinity-based predictions for assessing anthelmintic efficacy. Full article

Cracking occurred in the surface coating of a screw rotor during shale gas well operations. To determine whether the coating cracks could contribute to the failure of the 42CrMo substrate, the microstructure and morphology of surface cracks and local corrosion pits were examined and analyzed using a metallographic microscope, an SEM, and an EDS. To investigate the cross-sectional morphology and elemental distribution of corrosion pits, EDS mapping was performed. The composition of the corrosion products was characterized using Raman spectroscopy and XPS. In addition, four-point bend stress corrosion tests were conducted on screw rotor specimens under simulated service conditions. The results indicate that the P and S contents in the screw rotor substrate exceeded the specified limits, whereas its tensile and impact strengths satisfied the standard requirements. The microstructure consisted of tempered sorbite and ferrite, along with a small amount of sulfide inclusions. The corrosion products on the fracture surface were primarily identified as FeOOH, Fe₃O₄, and Cr(OH)₃. All specimens failed during the four-point bend tests. The chlorine (Cl) content in the corroded regions reached up to 8.05%. These findings demonstrate that the crack resistance of the 42CrMo screw rotor was markedly reduced under the simulated service conditions of 130 °C in a saturated, oxygenated 25% CaCl₂ solution. The study concludes that stress concentration induced by sulfide inclusions in the screw rotor, together with the combined effects of chloride ions, dissolved oxygen, and applied load, promotes the initiation and propagation of stress corrosion cracking. Therefore, it is recommended to strictly control the chemical composition and inclusion content of the screw rotor material and to reduce the oxygen content of the drilling fluid, thereby mitigating the risk of corrosion-induced cracking of the rotor. Full article

Syringic acid (SA) is a natural derivative of syringaldehyde (SD), derived from lignin depolymerization. Its application in the food industry focuses on the properties of natural functional ingredients; it is mainly used as a food antioxidant and food preservative, but can also be used as an ingredient to enhance food flavor and functional foods. This compound exhibits a remarkable spectrum of biological activities, including potent antioxidant, anti-inflammatory, neuroprotective, hypoglycemic, detoxifying, and anti-cancer effects, positioning it as a highly promising candidate for pharmaceutical and nutraceutical applications. In this study, suitable sites were first screened through homologous sequence alignment, and a variant of aryl-alcohol oxidase (CgAAO) with high efficiency in catalyzing the conversion of SD to SA was obtained via site-directed mutagenesis. A deep eutectic solvent (DES) system based on choline chloride/urea (ChCl/UR) in water was developed to enhance SA production. Additionally, key parameters of the biological reaction were optimized, including temperature, pH, metal ions, as well as the type and dosage of DES. The optimal performance was achieved using recombinant E. coli pRSFDuet-CgAAO-Y335F whole-cell biocatalysts, yielding 75% and producing 0.75 g/L SA in 100 mM KPB buffer (pH 7.0) containing 5 wt% ChCl/UR and 1 mM Fe³⁺. This study established a novel biosynthetic pathway for SA that was efficient, mild, green, and environmentally friendly. Full article

The development of a metalloenzyme-like catalytic system for the efficient oxidation of olefins under a dioxygen (O₂) atmosphere at room temperature is of significant interest in the field of catalysis. Herein, we present a highly active and selective aerobic epoxidation of olefins using metalloenzyme-like catalysts based on a non-heme ligand, tris(2-pyridylmethyl)amine (TPA). Notably, manganese chloride complexed with TPA (Mn(TPA)Cl₂) demonstrated excellent activity for the epoxidation of trans-stilbene using O₂ as the oxidant in the presence of a co-reductant at 30 °C. A quantitative conversion of 99% and high yield of 98%, as determined by gas chromatography using an external standard method, were achieved under optimum reaction conditions. Furthermore, Mn(TPA)Cl₂ exhibited a good substrate tolerance to styrene derivatives with electron-withdrawing or electron-donating groups, cyclic olefins with different substituents and substitution degrees, as well as long-chain olefins. Coupled with a high turnover frequency (TOF) of up to 30,720 h⁻¹, these results underscore the potential of Mn(TPA)Cl₂ as a promising metalloenzyme-like catalytic platform for the aerobic synthesis of diverse epoxides from olefins under ambient conditions. 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

Aromatic coconut (Cocos nucifera L.) is valued in the consumer market primarily for its distinctive fragrance, which is largely attributed to the compound 2-acetyl-1-pyrroline (2AP). The accumulation of 2AP has been observed in several crops, such as rice, when exposed to salt stress. In rice, exposure to salt stress influences the activity of enzymes, alters amino acid metabolism, and modulates the expression of genes associated with 2AP formation. Nevertheless, the processes responsible for 2AP biosynthesis in aromatic coconut under salt stress conditions are still not well clarified. In this study, five-month-old aromatic coconut seedlings were subjected to four distinct levels of sodium chloride (NaCl) treatment (0, 100, 200, and 300 mM). This experiment was conducted to investigate the mechanisms involved in salt-induced responses and the biosynthesis of 2AP in aromatic coconut. Although salt stress did not produce any apparent injury in the coconut seedlings, it led to a marked decline in chlorophyll content. Meanwhile, salt stress markedly enhanced the accumulation of betaine and boosted the activities of antioxidant enzymes such as superoxide dismutase and catalase. The aromatic coconut demonstrated a moderate level of salt tolerance. Salt stress also had a significant influence on 2AP biosynthesis. Under salt stress conditions, the 2AP content increased substantially, reaching its highest level with a 93.55% rise compared to the control. Furthermore, the synthesis of 2AP in aromatic coconut under salt stress appears to be primarily regulated through the metabolic pathways of proline and glutamate. Therefore, salt stress enhances 2AP production, with 200 mM NaCl identified as the optimal concentration for its accumulation. Full article

The pokeweed (Phytolacca americana L.) plant is native to North America and contains bioactive compounds with medicinal potential, particularly phenolics and saponins. This study enhanced the production of secondary metabolites in pokeweed callus cultures using sodium chloride (NaCl) and polyethylene glycol (PEG) as elicitors under aseptic conditions. Pokeweed seeds were cultured on Murashige and Skoog (MS) medium for 8 weeks. Fully expanded leaves from the second to third position from the shoot were excised and induced to form calli on MS medium supplemented with 2 mg/L 2,4-dichlorophenoxyacetic acid (2,4-D) for 5 weeks. Fully developed calli were elicited with PEG6000 at concentrations of 0, 1.25, 2.5, and 5% (w/v) in combination with NaCl at concentrations of 0, 100, 200, and 300 mM for 15 days. Callus growth was recorded, followed by drying and extraction using methanol (MeOH) for biochemical analysis. Calli elicited with 2.5% PEG and 300 mM NaCl exhibited the highest total phenolic content (TPC) (21.063 µg GAE/mg DW) and total flavonoid content (TFC) (1.927 µg QUE/mg DW). The highest antioxidant activities determined by the 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS), and ferric ion reducing antioxidant potential (FRAP) assays were 0.998, 1.574, and 0.998 µg TE/mg DW, respectively. The elicitation of pokeweed calli with 300 mM NaCl yielded the highest amount of Esculentoside A (EsA) (15.753 µg/mg DW). All the elicitor treatments significantly enhanced metabolite accumulation compared to the control group (p < 0.05). The findings indicated that elicitation with PEG and NaCl effectively enhanced the production of secondary metabolites in P. americana callus cultures. This study offers a promising alternative approach for utilizing P. americana in pharmaceutical and medicinal applications. Full article

This study aims to investigate the effects of Cr and Mo added to Fe-Al alloys on their corrosion behavior in acidic and chloride-containing environments. Corrosion tests were carried out in 0.5 M H₂SO₄ and 3.5 wt.% NaCl aerated aqueous solutions. X-ray diffraction analyses reveal that all alloys exhibited predominantly body-centered cubic structures in the homogenized states. In the 0.5 M H₂SO₄ solution, the addition of Cr can effectively reduce the critical current density; however, the anodic and cathodic polarization curves still intersected three times, similar to the alloy without the addition of Cr, resulting in three corrosion potentials. With the further addition of Mo, the critical current density became much lower, leading to a single corrosion potential. In the 3.5 wt.% NaCl solution, the addition of Cr alone markedly improved the pitting resistance of Fe-Al alloys, while the further addition of Mo broadened the passive region and increased the pitting potential. The analysis of ion concentrations was consistent with the potentiodynamic polarization results, verifying the stabilization of Mo on the passive film. It is evident that the addition of Cr promotes passivation of the Fe-Al alloy, and the further incorporation of Mo enhances this effect even more significantly. The related corrosion mechanisms are discussed with Nerst equations of metal–metal oxides and their solubility products (K_sp). Full article

Atomic layer deposition (ALD) was employed to fabricate single-layer Al₂O₃, single-layer ZrO₂, and Al₂O₃/ZrO₂ nanolaminate coatings on SUS304 to enhance corrosion protection in chloride-containing environments. All coatings were deposited at 250 °C using optimized self-limiting ALD processes, and the total film thickness was controlled at approximately 54 nm for a fair comparison. Structural characterization revealed that Al₂O₃ films remained amorphous, whereas ZrO₂ films exhibited a thickness-dependent transition from amorphous to crystalline phases. In the nanolaminate structures, thinner ZrO₂ sublayers (<9 nm) retained amorphous or locally nanocrystalline characteristics, while thicker ZrO₂ sublayers (15 nm) developed polycrystalline features with increased grain boundary density. Electrochemical corrosion tests conducted in 3.5 wt% NaCl solution demonstrated that the Al₂O₃/ZrO₂ nanolaminate coatings exhibited significantly lower corrosion current densities and delayed pitting corrosion compared to single-layer coatings. Among all samples, the [Al₂O₃ (15 nm)/ZrO₂ (3 nm)] × 3 nanolaminate showed the best corrosion resistance, with the lowest corrosion current density (I_corr = 6.20 nA/cm²) and the highest protective efficiency (98.34%). These results highlight the critical role of nanolaminate architecture and sublayer crystallinity in suppressing ionic diffusion and provide an effective strategy for designing ultrathin, high-performance corrosion barrier coatings for stainless steel. Full article

Herein, we report the synthesis, characterization, and catalytic evaluation of cobalt hydroxide chloride [Co₂(OH)₃Cl] in the solvent-free synthesis of 2-substituted 2,3-dihydroperimidines. The presented method aligns with several green chemistry principles, offering operational simplicity, purification by recrystallization, no by-product formation, high yields (64–99%), and short reaction times. A total of 16 dihydroperimidines were synthesized to demonstrate substrate scope versatility. Additionally, the catalyst was successfully recycled and reused in multiple cycles without significant loss. Its robustness was further confirmed by gram-scale synthesis, achieving an 89% yield. Full article

Avicennia germinans, a representative of the marine coastal mangrove ecosystem, vital in the Colombian Caribbean, harbors a unique microbial diversity that could contain microorganisms with the potential to promote plant growth of agricultural species such as maize. The objective of this research was to evaluate A. germinans endophytes at different sampling sites and in diverse plant organs in order to identify the growth-promoting role of the most sodium chloride-tolerant endophyte found. These were then inoculated in maize seeds under drought stress conditions simulated by polyethylene glycol (PEG) in vitro. To this end, samples of adult A. germinans plants were collected from four mangrove ecosystems in the Colombian Caribbean. Several isolates were able to tolerate up to 15% NaCl (w/v), produce indole-3-acetic acid (IAA), show proteolytic activity, and inhibit phytopathogenic fungi. The best-performing strain, C1T-KM1901-B, was genomically identified as Bacillus paralicheniformis and evaluated as a bioinoculant in maize seeds under PEG-induced drought stress. Inoculation with B. paralicheniformis significantly increased germination potential and germination index of drought-resistant seeds compared to non-inoculated controls under severe drought stress conditions (40% PEG). In addition, inoculated seedlings exhibited significantly higher roots and shoot fresh and dry biomass at moderate to severe drought stress levels (15% and 20% PEG). These results are position B. paralicheniformis C1T-KM1901-B, isolated from Avicennia germinans, as a promising bioinoculant to enhance maize establishment under drought conditions. Full article

Heavy metals (arsenic, cadmium, and lead) remain one of the most common and complex environmental problems worldwide. Accordingly, there is a growing need for eco-friendly and affordable materials derived from agricultural waste for the removal of heavy metals from contaminated water. This study aims to demonstrate how biodegradable pineapple leaf cellulose (PLC) can be used effectively in the remediation of heavy metals. The PLC adsorbent was prepared by treating it with ethyl alcohol (EtOH, 99.5%), calcium chloride (CaCl₂), and 0.8 M sodium hydroxide. A scanning electron microscope equipped with energy-dispersive X-ray spectroscopy (SEM-EDS) and Fourier transform infrared spectroscopy (FT-IR) was used to investigate the surface of the adsorbent. Inductively coupled plasma mass spectrometry (ICP-MS) was employed to measure the concentration of metals before and after adsorption. Removal of metal ions (As⁵⁺, Cd²⁺, and Pb²⁺) by PLC was investigated under varying conditions, including pH, contact time, and adsorbent dosage. The analysis of cellulose composite revealed significant potential for adsorption of heavy metals such as As⁵⁺, Cd²⁺, and Pb²⁺. The highest removal efficiency of heavy metal ions was detected at a pH ranging from 3 to 7. The biosorption order of PLC at pH 6 was Pb²⁺ > Cd²⁺ > As⁵⁺ with 99.53% (63.45 mg/g), 98.44% (37.23 mg/g), and 42.40% (16.27 mg/g), respectively. After 120 min, the equilibrium of the adsorption process was reached for As⁵⁺, Cd²⁺, and Pb²⁺. FT-IR characterization discovered an increased abundance of functional groups on the adsorbent. The SEM-EDS analysis confirmed the occurrence of elements on the surface of PLC. The study revealed that the use of PLC is an innovative method for removing heavy metals from aquatic milieus, a potential resource for eco-friendly and affordable wastewater treatment. 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