Search Results (135)

This study investigates the effect of precursor pH (1.3, 2, 4, 6, 8, and 10) on the synthesis of gold nanoparticles (AuNPs) via a green synthesis approach using an aqueous extract of green tea (Camellia sinensis) leaves. The formation of AuNPs was monitored using UV-vis spectrophotometry and confirmed using transmission electron microscopy (TEM). The results confirmed that the morphology and size of the AuNPs are strongly dependent on the pH of the reaction medium. Based on spectral features, the color of the colloids, and TEM analysis, the synthesized samples were classified into three groups. The first (pH 8 and 10) contained predominantly spherical nanoparticles with an average diameter of ~18 nm, the second (pH 1.3 and 2) contained different shaped nanoparticles (20–250 nm in diameter), and the third (pH 4 and 6) contained flower-like nanostructures with a mean diameter of ~60 nm. UV-vis analysis revealed good stability of all AuNP colloids, except at pH 1.3, where a significant decrease in absorbance intensity over time was observed. These findings confirm that tuning the precursor pH allows for controlled manipulation of nanoparticle morphology and stability in green synthesis systems. Full article

(1) Background: Our study investigates the green synthesis of Ag₂O/Ag nanoparticles using the isoflavone Puerarin as a bioreductor. (2) Methods: The PUE@Ag₂O/Ag nanoparticles were characterized using various techniques, including X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), electronic microscopy (TEM, SEM), energy dispersive X-ray spectroscopy (EDX), and dynamic light scattering (DLS). Biological activities were assessed through antimicrobial testing, cytotoxicity assays on human keratinocytes and melanoma cells, and an in ovo screening using the HET-CAM assay. (3) Results: The formation of crystalline Ag₂O/Ag nanoparticles with sizes below 100 nm was accomplished with Puerarin. Despite their high cytotoxicity at all tested concentrations, the nanoparticles showed antioxidant activity with IC₅₀ 981.5 ± 94.2 μg/mL, antibacterial activity against several clinically relevant nosocomial strains (Streptococcus pyogenes, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa), and no local irritant effects or inhibition of angiogenesis in the HET-CAM assay. (4) Conclusions: This study provides insights into the synthesis, characterization, and biological profile of PUE@Ag₂O/Ag nanoparticles for potential biomedical applications. Full article

In the current context, where environmental concerns are gaining increased attention, the transition toward sustainable urban mobility stands out as a necessary and responsible step. Technological advancements over the past decade have brought private autonomous vehicles, particularly those defined by the Society of Automotive Engineers Levels 4 and 5, into focus as promising solutions for mitigating road congestion and reducing greenhouse gas emissions. However, the extent to which Autonomous Vehicles can fulfill this potential depends largely on user acceptance, patterns of use, and their integration within broader green energy and sustainability policies. The present paper aims to develop an integrated conceptual model that links behavioral determinants to environmental outcomes, assessing how individuals’ intention to adopt private autonomous vehicles can contribute to sustainable urban mobility. The model integrates five psychosocial determinants—perceived usefulness, trust in technology, social influence, environmental concern, and perceived behavioral control—with contextual variables such as energy source, infrastructure availability, and public policy. These components interact to predict users’ intention to adopt AVs and their perceived contribution to urban sustainability. Methodologically, the study builds on a narrative synthesis of the literature and proposes a framework applicable to empirical validation through structural equation modeling (SEM). The model draws on established frameworks such as Technology Acceptance Model (TAM), Theory of Planned Behavior, and Unified Theory of Acceptance and Use of Technology, incorporating constructs including perceived usefulness, trust in technology, social influence, environmental concern, and perceived behavioral control, constructs later to be examined in relation to key contextual variables, including the energy source powering Autonomous Vehicles—such as electricity from mixed or renewable grids, hydrogen, or hybrid systems—and the broader policy environment (regulatory frameworks, infrastructure investment, fiscal incentives, and alignment with climate and mobility strategies and others). The research provides relevant directions for public policy and behavioral interventions in support of the development of clean and smart urban transport in the age of automation. Full article

High and large-spectrum antibacterial features and ROS scavenging properties are the most important requirements for efficient wound-dressing materials. A composite hydrogel was synthesized herein by a one-pot procedure embedding silver nanoparticles (AgNPs) covered with oxidized gum arabic (OGA) within gelatin (Gel) hydrogel. Small (2–20 nm), round-shaped AgNPs (ζ = −22 mV) were first obtained by green synthesis using OGA as a reducing and capping agent. Composite hydrogels, containing 0.6 and 1.3 wt.% Ag, were obtained by the covalent cross-linking (Schiff base reaction) of amine groups in gelatin with the dialdehyde groups located on the shell of the AgNPs. Thus, the uniform distribution of the AgNPs in the network contributed to the increased physicochemical and hydrolytic stability of the hydrogels. Moreover, the high swelling degree together with the good mechanical properties make them appropriate candidates for wound-healing materials. The hydrogels exhibited 80% scavenging activity of ABTS^●+ free radicals after 6 h of incubation and were effective against E. coli and S. aureus, achieving a 4% survival of bacteria within 3 h (E. coli) and 24 h (S. aureus). These results clearly indicate that the proposed hydrogels have potential in wound-dressing applications. Full article

The gas-liquid sulfonation of α-olefin sulfonate (AOS) in falling film reactors faces significant limitations, primarily due to poor mass transfer efficiency and excessive byproduct formation. To overcome these challenges, a novel cross-shaped microchannel reactor was developed for the continuous gas-liquid sulfonation of α-olefin (AO) with gaseous sulfur trioxide (SO₃). The influence of key process parameters, including gas-phase flow rate, reaction temperature, SO₃/AO molar ratio, and SO₃ volume fraction, on product characteristics and their interactions was systematically investigated using the single-factor experiment and response surface methodology (RSM). A high-precision empirical model (coefficient of determination, R² = 0.9882) to predict product content was successfully constructed. To achieve multi-objective optimization considering product active substance content and energy efficiency, a strategy combining a two-population genetic algorithm with the entropy-weighted TOPSIS (Technique for Order of Preference by Similarity to Ideal Solution) method was implemented. Optimal conditions were determined as follows: gas-phase flow rate of 228 mL/min, reaction temperature of 52 °C, SO₃/AO molar ratio of 1.27, and SO₃ volume fraction of 4%. Compared to conditions optimized solely by RSM, this multi-objective approach achieved a significant 10% reduction in energy efficiency, with only a marginal 3.8% decrease in active substance content. This study demonstrates the feasibility and advantages of microreactors for the efficient and green synthesis of AOS. Full article

Recently, attention has shifted towards the green synthesis of nanoparticles using plant extracts rich in phytochemicals like phenols and flavonoids, offering an alternative method that avoids harmful chemicals and enables large-scale, low-cost production. This study introduces a straightforward and eco-friendly approach to synthesizing hematite α-Fe₂O₃ nanoparticles utilizing an aqueous extract of Musa paradisiaca. The variation in the calcination temperature resulted in the formation of nanoparticles presented as Fe₂O₃ (1), Fe₂O₃ (2), and Fe₂O₃ (3), obtained at 650, 750, and 900 °C for 4 h, respectively. This variation allowed for an investigation into the impact of different reaction temperatures on the structural and optical properties of the nanoparticles. Structural analysis was conducted using X-ray diffraction (XRD), while scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were employed to examine morphology. Optical properties were assessed via UV-vis spectroscopy, revealing a reduction in the energy band gap (from 2.5 to 1.87 eV), attributed to an increase in crystallite size resulting from longer calcination temperatures (650–900 °C). A biological assay was carried out to evaluate the antioxidant and anticancer potentials of the nanoparticles. Both Fe₂O₃ (1) and Fe₂O₃ (2) with IC₅₀ values of 46.84 and 46.14 µg/mL, respectively, showed similar antioxidant potentials, while peel extract exhibited the least activity with an IC₅₀ of 79.26 µg/mL. The nanoparticles, peels, and 5-FU (used as standard) showed a stronger inhibitory effect on the Human Embryonic Kidney (HEK) 293 cells compared to the HeLa cells. This implies that the HEK 293 cells might be more susceptible to the drug samples and a lower concentration might even be sufficient to achieve the inhibition of normal cell proliferation. These results indicate a better therapeutic window with a lesser inhibitory effect compared to standard drugs used as controls. Full article

This study introduces a green synthesis strategy for producing high-purity alumina (≥99.99%) through the controlled hydrolysis of aluminum isopropoxide, coupled with a novel impurity removal protocol to address persistent challenges in conventional methods, such as residual silicon/iron impurities and particle agglomeration. The experimental results indicate that La₂O₃, 1-(2-pyridylazo)-2-naphthol (PAN), and phenolphthalein exhibit effective removal capabilities for silicon/iron impurities. The addition of 1 wt% La₂O₃ reduces silicon content from 99.7 ppm to 16.4 ppm, whereas 0.6 wt% PAN and 0.2 wt% phenolphthalein, employed as iron-binding agents, lower iron content from 66.4 ppm to 20.7 ppm and 9.7 ppm, respectively. Through optimized dropwise hydrolysis and subsequent calcination at 1200 °C for 4 h, nanosized alumina powders with uniform morphology and controlled particle sizes (274–832 nm) were successfully synthesized. The proposed method offers a scalable and efficient pathway for synthesizing high-purity alumina with tailored particle characteristics. Full article

In this study, the mitigating effects of CaO NPs obtained from pomegranate extract via environmentally friendly green synthesis on CdCl₂ stress in two varieties (Yolboyu and Kirac) of Turkish Kavilca wheat (Triticum dicoccum Schrank) under in vitro callus culture conditions were investigated. The calluses developed from embryos of both wheat varieties were exposed to either CaO NPs alone (1 and 2 mg/L), CdCl₂ alone (1 or 10 mM) or the different combinations of these two compounds in MS medium for 4 weeks. Changes in the expressions of two genes (Traes_5BL_9A790E8CF and Traes_6BL_986D595B9) known to be involved in wheat’s response to CdCl₂ stress were analyzed by qRT-PCR. Additionally, certain physiological parameters, such as lipid peroxidation (LPO), H₂O₂, proline and soluble sugar content, and SEM-EDX analysis were used to assess the response of calluses to the applications. The CaO NPs treatments alone generally upregulated the expression of the 5BL and 6BL genes, while the CdCl₂ applications decreased their expression in both cultivars. The CaO NPs reduced the proline content in both cultivars compared to the control. Co-treatment with CdCl₂ and CaO NPs increased the sugar content and decreased the MDA content, but did not cause a significant change in the H₂O₂ content. SEM analysis showed that when CdCl₂ and CaO NPs were applied to calluses together, the membranous and mucilaginous spherical structures were regained. The application of CaO NPs reduces the amount of cellular damage caused by CdCl₂ stress and improves gene expressions. Full article

The catalytic esterification of levulinic acid (LA) to methyl levulinate (ML) was investigated using copper molybdate (Cu₃(MoO₄)₂(OH)₂) as a heterogeneous catalyst. The catalyst, synthesized via chemical precipitation, exhibited a monoclinic structure with self-assembled nanoplates forming spherical mesostructures. Structural characterization confirmed its high crystallinity, while textural analysis revealed a BET surface area of 70.55 m² g⁻¹ with pore sizes in the nanometric range (1–6 nm). The catalytic performance was systematically evaluated under varying reaction conditions, including temperature, catalyst dosage, reaction time, methanol-to-LA molar ratio, alcohol type, and catalyst reusability. Optimal conversion of 99.3% was achieved at 100 °C, a 1:20 methanol-to-LA molar ratio, 5% catalyst loading, and a reaction time of 4 h. Comparative analysis with other heterogeneous catalysts demonstrated superior efficiency and stability of Cu₃(MoO₄)₂(OH)₂, with minimal activity loss over four reuse cycles (final conversion of 77.1%). Mechanistic insights suggest that its high activity is attributed to Lewis and Brønsted acid sites, facilitating efficient esterification. This study underscores the potential of copper molybdate as a sustainable and recyclable catalyst for biofuel additive synthesis, advancing green chemistry strategies for biomass valorization. Full article

Low temperature stress represents a significant abiotic stress factor affecting rice yields. While the structure and some of the functions of cell cycle protein-dependent protein kinase inhibitor (CKI) family proteins have been the subject of study, their relevance to cold tolerance in rice has been less investigated. In this study, we cloned OsEL2 (LOC_Os03g01740) and constructed anti-expression lines of this gene. The resulting lines exhibited significant cold sensitivity and displayed greater oxidative damage than wild type Nippobare (Nip). However, the activities of antioxidant enzymes, such as catalase (CAT), were significantly elevated in OsEL2-AX plants in comparison to Nip following exposure to 4 °C stress. RNA sequencing revealed the presence of 18,822 differential genes, with the majority of them being expressed with temporal specificity. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis revealed that a considerable number of differentially expressed genes (DEGs) are involved in the metabolism of amino acids, lipids, and terpenoids. Weighted gene co-expression network analysis (WGCNA) revealed a close relationship between the genes in the turquoise and light green modules and rice cold tolerance traits. These genes were predominantly enriched in terpene metabolism and the metabolism of various plant secondary metabolites, suggesting that OsEL2 influences rice cold tolerance through the metabolism of these two classes of substances. An analysis of the genes within these two modules using transcription factor (TF) enrichment and KEGG enrichment revealed that they are predominantly regulated by mitogen-activated protein kinase (MAPK) and ethylene signaling pathways. Furthermore, we found that tryptophan metabolism, phenylalanine metabolism, and monoterpene synthesis were enriched in down-regulated pathway enrichment analysis. In addition, we also found that the MAPK signaling pathway was enriched in the KEGG enrichment analysis of AX2 with Nip. The results demonstrate that anti-expression of OsEL2 is associated with a notable decline in rice tolerance to cold stress. Full article

As the demand for high-performance polymers broadens, polyurethane (PU) polymers with various chemical modifications have attracted attention. This review explores the chemical structure and functional variations of PUs. PUs are used in a variety of fields, ranging from aerospace engineering to daily necessities, and show remarkable safety adaptability through designable synthesis processes. This study is divided into four main parts: (1) synthesis and structure, covering the synthesis of PU base and modification of additive compounds; (2) performance, studying physical properties and thermal degradation processes; (3) application, evaluating the commercial potential of PU polymers; and (4) flame retardancy, analyzing five established flame-retardant mechanisms. The last part discusses how PUs can meet sustainable development goals by replacing petroleum-based materials with green materials. By emphasizing non-petroleum resources and novel, sustainable modification strategies, this review conducts guidance for the safe and environmentally friendly application of PUs in the future. Full article

Nanoparticles play an important role in plant response to abiotic stresses including salt stress. In this study, the physiological and histological responses of CuO, ZnO, and CaO nanoparticle (NP) applications on callus tissues developed from two alfalfa lines (Erzurum and Muş) exposed to salt (NaCl) stress were evaluated. The NPs were synthesized from the extracts obtained from healthy walnut shells using the green synthesis approach and then characterized by Scanning Electron Microscopy (SEM) and X-ray diffraction analysis (XRD). The leaf explants were placed in an MS medium containing 4 mg L⁻¹ 2,4-D (2,4-dichlorophenoxyacetic acid), 50 mM NaCl, and 0.8 ppm of NPs for 1 month in the dark. CaO NP is determined to be more effective than CuO and ZnO in callus induction from leaf explants. Malondialdehyde (MDA) content was higher in the callus treated with 0.8 ppm CuO NP + 50 mM NaCl compared to other treatments. The callus induction stage, without salt treatments, showed the best results with 0.8 ppm CaO NPs for both H₂O₂ levels and peroxidase (POX) activity compared to the other NPs. The highest protein rate was obtained from the callus induction stage and callus formation stage after 50 mM treatment NaCl with 0.8 ppm CuO. The LCSM results displayed, under in vitro conditions, that the treatment of NPs can greatly suppress the negative effects of salt stress on calli samples. SEM analysis supported the results obtained by laser scanning confocal microscopy (LSCM) analysis. Our findings suggest that CuO, CaO, and ZnO NPs can offer a simple and effective method to protect alfalfa callus from NaCl stress severity. Furthermore, these NPs, particularly CaO, hold potential for broader application and should be evaluated under various abiotic conditions beyond salt stress. Full article

We aimed to synthesize silver nanoparticles (AgNPs) using Elettaria cardamomum (cardamom) extracts and assess the cytotoxicity and genotoxicity of the cardamom extract, cardamom–AgNPs, and the insecticide ATCBRA—commonly used for pest control—on the root system of Vicia faba (broad bean). The chemical composition of the aqueous cardamom extract was identified and quantified using GC-MS, revealing a variety of bioactive compounds also present in cardamom essential oil. These included α-terpinyl acetate (21.3–44.3%), 1,8-cineole (10.7–28.4%), and linalool (6.4–8.6%). The successful green synthesis of AgNPs was confirmed through various micro-spectroscopic techniques, including UV-Vis spectroscopy, transmission electron microscopy (TEM), and energy-dispersive spectroscopy (EDS). UV-Vis analysis showed a strong peak between 420 and 430 nm, indicating the presence of AgNPs. TEM imaging revealed that the synthesized cardamom–AgNPs were monodispersed, primarily spherical, and semi-uniform in shape, with minimal aggregation. EDS analysis further confirmed the composition of the nanoparticles, with cardamom–AgNPs comprising around 60.5% by weight. Cytotoxicity was evaluated by measuring the mitotic index (MI), and genotoxicity was assessed by observing chromosomal aberrations (CAs). The roots of Vicia faba were treated for 24 and 48 h with varying concentrations of ATCBRA pesticide (0.1%, 0.3%, 0.5%, and 0.7%), aqueous cardamom extract (3%, 4%, 5%, and 6%), and green-synthesized cardamom–AgNPs (12, 25, and 60 mg). The cytogenetic analysis of MI and CA in the meristematic root tips indicated an improvement in the evaluated parameters with the cardamom extract. However, a marked reduction in mitotic activity was observed with both ATCBRA and cardamom–AgNP treatments across both time points, highlighting potential cytotoxic and genotoxic effects. Full article

The present research aims to valorize biofloc waste by extracting polyphenols via alkaline hydrolysis, utilizing them as reducing and stabilizing agents in the optimization of green synthesis of silver nanoparticles (BIOAgNPs). For the alkaline extractions, potassium hydroxide (KOH) concentrations of 0 to 4 M were used in combination with ultrasound. Total polyphenol content and antioxidant activity were evaluated. BIOAgNPs synthesis was optimized using the response surface methodology and central composite design. The parameters time, temperature, AgNO₃ concentration, and the percentage of the biofloc extract (2 M KOH), with measurements taken for the area under the curve (AUC) (400–500 nm) and the mean hydrodynamic diameter (DLS), were evaluated. Antibacterial activity was determined for Gram-negative and Gram-positive bacteria. Higher polyphenol content and antioxidant activity were observed using 2 M KOH. The optimized model for DLS and the AUC was obtained in 4 h, at 40 °C, using 2.4 mM AgNO₃ and obtaining 2.5% of extract. Optimized BIOAgNPs had a diameter of 22.4 nm, hydrodynamic diameter of 106.5 nm, zeta potential of −28 mV, and polydispersity index of 0.26. BIOAgNPs demonstrated bactericidal activities. This study enhanced the valorization of aquaculture residues through improved polyphenol extraction techniques and developed an effective methodology for synthesizing silver nanoparticles with antimicrobial activity. Full article

Testosterone (TS) and its 1(2)-dehydrogenated derivative boldenone (BD) are widely used in medicine, veterinary science and as precursors in organic synthesis of many therapeutic steroids. Green production of these compounds is possible from androstenedione (AD) enzymatically, or from phytosterol (PS) using fermentation stages. In this study, the ascomycete Curvularia sp. VKM F-3040 was shown to convert androstadienedione (ADD, 4 and 10 g/L) to yield 97% and 78% (mol/mol) of BD, respectively. Based on its high 17β-hydroxysteroid dehydrogenase (17β-HSD) activity, a novel cascade biotransformation of PS was developed for production of TS and BD. At the first stage, the strains of Mycolicibacterium neoaurum VKM Ac-1815D or M. neoaurum VKM Ac-1816D converted PS (5 or 10 g/L) into AD or ADD (each in a concentration of 2.5 or 5 g/L), respectively. At the second stage, mycelium of the fungus under the revealed optimal conditions reduced AD or ADD with more than 90% efficiency to form TS or BD, respectively. Based on transcriptome analysis, six candidate genes that might encode 17β-HSDs in the Curvularia sp. genome were revealed. Along with 17β-HSDs, the fungus possessed inducible P450_cur 7-monooxygenase, which led to the accumulation of 7α-hydroxytestosterone (7α-OH-TS) as a major product from AD (up to 83% within 24 h after mycelium addition at the second stage of cascade biotransformation). The presence of protein synthesis inhibitor cycloheximide (CHX) prevented 7α/β-hydroxylation due to inhibition of de novo synthesis of the enzyme in the fungal cells. The results demonstrate the high biotechnological potential of the Curvularia sp. strain and open up prospects for the synthesis of valuable 17β-reduced and 7-hydroxylated steroids by cascade biotransformations. Full article