Search Results (357)

Lotus stems contain cellulose, which can be utilized as a base material for producing green products, specifically degradable plastics. This research investigates the effect of polylactic acid (PLA) blends on cellulose degradable plastics from the lotus stem (Nelumbo nucifera). The mechanical characteristics are as follows: tensile strength of 0.7703–3.3212 MPa, elongation of 0.58–1.16%, Young’s modulus of 78.7894–364.6118 MPa. Compound analysis showed the presence of O-H, C-C, and C=O groups, and the presence of microbial activity in the soil can also lead to the degradation of these groups due to their hydrophilic nature, which allows them to bind water. Thermal analysis within a temperature range of 413.24 °C to 519.80 °C, shows that significant weight loss begins with the formation of crystalline structures. The degradable plastic exhibiting the lowest degree of swelling consists of 1 g of cellulose and 8 g of PLA, resulting in a swelling value of 6.25%. The degradable plastic is anticipated to decompose most rapidly after 52 days, utilizing 2 g of PLA and 7 g of cellulose. This complies with standard requirement, which sets a maximum degradation period of 180 days for polymers. Full article

The search for novel natural resources, such as extracts from algae and plant for use as reductants and capping agents for the synthesis of nanoparticles, may be appealing to medicine and nanotechnology. This study aimed to use Malva parviflora fruit extract as a novel source for the green synthesis of silver nanoparticles (AgNPs) and to evaluate their characterization. The results of biosynthesized AgNP characterization using multiple techniques, such as UV–Vis spectroscopy, scanning electron microscopy (SEM), FTIR analysis, and zeta potential (ZP), demonstrated that M. parviflora AgNPs exhibit a peak at 477 nm; possess needle-like and nanorod morphology with diameters ranging from 156.08 to 258.41 nm; contain –OH, C=O, C-C stretching from phenyl groups, and carbohydrates, pyranoid ring, and amide functional groups; and have a zeta potential of −21.2 mV. Moreover, the antibacterial activity of the M. parviflora AgNPs was assessed against two multidrug-resistant strains, including Staphylococcus aureus MRSA and Escherichia coli ESBL, with inhibition zones of 20.33 ± 0.88 mm and 13.33 ± 0.33 mm, respectively. The minimum bactericidal concentration (MBC) was 1.56 µg/mL for both. SEM revealed structural damage to the treated bacterial cells, and RAPD-PCR confirmed these genetic alterations. Additionally, M. parviflora AgNPs showed antioxidant activity (IC₅₀ = 0.68 mg/mL), 69% protein denaturation inhibition, and cytotoxic effects on MCF-7 breast cancer cells at concentrations above 100 µg/mL. These findings suggest that M. parviflora-based AgNPs are safe and effective for antimicrobial and biomedical applications, such as coatings for implanted medical devices, to prevent biofilm formation and facilitate drug delivery. Full article

Pyridyl-thiourea complexes of formula [(Cym)MCl(κ²N_py,S-H₂NNS)][SbF₆] (Cym = η⁶-p-MeC₆H₄iPr; H₂NNS = N-(p-tolyl)-N′-(2-pyridylmethyl)thiourea); M = Ru (1), Os (2)) were synthesized by reacting the corresponding metal dimers [{(Cym)MCl}₂(μ-Cl)₂] with H₂NNS in the presence of NaSbF₆. Subsequent chloride abstraction with AgSbF₆, followed by NH deprotonation using NaHCO₃, afforded the cationic complexes [(Cym)M(κ³N_py,N_amide,S-HNNS)][SbF₆] (M = Ru (5a), (5c); M = Os (6a, 6c)) and [(Cym)M(κ²N_amide,S-HNNS)][SbF₆] (M = Ru (5b); M = Os (6b)). The proposed structures for the prepared compounds are based on NMR data. Complexes 5a, 5b, and 6a, 6b evolve to the thermodynamically more stable species 5c and 6c, respectively, in which the deprotonated ligand HNNS adopts a κ³N_py,N_amide,S coordination mode. Complexes 5c and 6c activate H₂, behaving as frustrated Lewis pair (FLP) species, and catalyze (5c and/or 6c) the hydrogenation of polar multiple bonds, including the C=N bonds of N-benzylideneaniline and quinoline, the C=C bond of methyl acrylate, and the C=O bond of 2,2,2-trifluoroacetophenone. Full article

Melanoidins, generated during the Maillard reaction in soy sauce fermentation, have potential health benefits due to its excellent bioactivity. This study aimed to investigate the antioxidant contributions and structural characteristics of melanoidins in soy sauce. Five molecular weight fractions (1–3 kDa, 3–10 kDa, 10–30 kDa, 30–50 kDa, and >50 kDa) were isolated and their composition was analyzed. Results showed that soy sauce melanoidins mainly comprised proteins, sugars, and phenolic compounds. Antioxidant activities of the melanoidins were influenced by their molecular weights and structures. The >50 kDa melanoidins fraction contributed the most to the overall antioxidant activities of soy sauce. The total contributions of melanoidins to the antioxidant activities of soy sauce ranged from 34.21% to 75.03%. Spectroscopic analyses indicated that the antioxidant activities were positively correlated with the presence of conjugated structures and active functional groups (i.e., C=C, C=O, N-H, O-H) in melanoidins. This study provides new insights into the health-promoting properties of soy sauce melanoidins and offers theoretical support for the development of soy sauce as a functional food. Full article

Laser cladding rapid solidification technique is an effective strategy for manufacturing ultra-high-strength martensitic stainless steels (UHS-MSS). Due to super-saturation solution strengthening of interstitial atoms (IAs), martensitic stainless steels containing IAs exhibit excellent ultra-high strength and toughness and have high tolerance for oxygen impurities. Hence, studying the specific speciation and structural characteristics of IAs is of great significance for guiding laser cladding of ultra-high-strength steels. Herein, we use density functional theory (DFT) computations to analyze the stable occupancies of IAs and their interactions in body-centered cubic iron (BCC Fe). The findings show that single IAs prefer to occupy octahedral sites over tetrahedral sites. Therefore, octahedral sites are selected as the optimal sites for the following double IAs study. For homo IAs, C-C and N-N configurations exhibit greater stability at long-range distances, whereas O-O demonstrate optimal stability at intermediate distances. Crucially, hetero IAs configurations are more stable compared to single IAs and homo IAs, exhibiting a synergistic effect. Especially, the C-O combination shows the highest stability and strongest bonding character. Meanwhile, the dissociation behavior of O indicates that C-O and N-O have higher dissociation temperatures than single O, further verifying the synergistic effect of hetero IAs. This provides a theoretical basis for understanding the interstitial solution strengthening of laser cladding UHS-MSS. Full article

Despite the significant advancements in treatment and prevention, the fight against cancer is ongoing worldwide. This study evaluated the pharmacological properties and anticancer activity of Afzelia quanzensis bark, traditionally used by the indigenous communities of KwaZulu Natal and Eastern Cape Provinces of South Africa to treat cancer and related illnesses. Phytochemical screening, high-performance liquid chromatography–diode array detection (HPLC-DAD), and Fourier-transform infrared spectroscopy (FTIR) analyses were carried out using established protocols. The antioxidant activity was assessed via the 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging capacity and nitric oxide radicals. The anticancer activity was evaluated using the MTT assay (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide). Phytochemical analysis revealed the presence of saponins, flavonoids, terpenoids, alkaloids, steroids, cardiac glycosides, and phlobatannins. The HPLC-DAD analysis detected seven distinctive peaks in the aqueous extract and three distinctive peaks in the methanolic extract. The FTIR spectra of the aqueous extract displayed characteristic peaks corresponding to O-H, C=O, C=C, and =C–H functional groups. Among the tested extracts, the methanol extract exhibited the strongest antioxidant activity, followed by the ethanolic extract, in both DPPH and nitric oxide. The methanol extract showed a higher cell proliferation inhibition against the DU-145 cancer cell line with the percentage of inhibition of 37.8%, followed by the aqueous extract with 36.3%. In contrast, limited activity was observed against PC-3, SK-UT-1, and AGS cell lines. The results demonstrated notable dose-dependent antioxidant and antiproliferative activities supporting the ethnomedicinal use of Afzelia quanzensis bark in cancer management. These findings warrant further investigation into its bioactive constituents and mechanisms of action. Full article

Background: Charcot–Marie–Tooth disease (CMT) is a genetically and phenotypically heterogeneous hereditary neuropathy. Axonal CMT type 2 (CMT2) subtypes often exhibit overlapping clinical features, which makes molecular genetic analysis essential for accurate diagnosis and subtype differentiation. Methods: This retrospective study included five pediatric patients who presented with gait disturbance, muscle weakness, and foot deformities and were subsequently diagnosed with axonal forms of CMT. Clinical data, electrophysiological studies, neuroimaging, and genetic analyses were evaluated. Whole exome sequencing (WES) was performed in three sporadic cases, while targeted CMT gene panel testing was used for two siblings. Variants were interpreted using ACMG guidelines, supported by public databases (ClinVar, HGMD, and VarSome), and confirmed by Sanger sequencing when available. Results: All had absent deep tendon reflexes and distal muscle weakness; three had intellectual disability. One patient was found to carry a novel homozygous frameshift variant (c.2568_2569del) in the IGHMBP2 gene, consistent with CMT2S. Other variants were identified in the NEFH (CMT2CC), DYNC1H1 (CMT2O), and MPV17 (CMT2EE) genes. Notably, a previously unreported co-occurrence of MPV17 mutation and congenital heart disease was observed in one case. Conclusions: This study expands the clinical and genetic spectrum of pediatric axonal CMT and highlights the role of early physical examination and molecular diagnostics in detecting rare variants. Identification of a novel IGHMBP2 variant and unique phenotypic associations provides new insights for future genotype–phenotype correlation studies. Full article

Papilloscopy, the science of human identification through fingerprints, has seen notable advancements in developing less toxic latent fingerprint developers (LFDs), especially from natural feedstock. Tannins, the second most abundant natural polyphenol, present a potential eco-friendly and cost-effective alternative, with no record of their use as LFDs in the existing literature. This study characterized four types of tannins from black wattle, using Fourier Transform Infrared Spectroscopy, revealing key functional groups like C=O, C=C, and O–H. Ultraviolet–visible absorption spectra showed similar behaviors for all tannins, indicating phenolic and benzenoid structures. Energy-dispersive X-ray Spectroscopy identified high concentrations of chlorine, sodium, potassium, and sulfur, naturally found in biomass and soil. Finally, elements in significant concentrations, such as sodium, potassium, iron, zinc, and copper, were found through the incineration of the spent bark. On the basis of these findings, the tannin with the highest potential for LFD was selected. Combining this tannin with spent bark ash resulted in a composite whose performance was evaluated using different methods, including depletion studies, tests with various donors, and assessments on different surfaces. The results demonstrated that this combination significantly enhanced the material’s efficiency by integrating organic and inorganic properties, which improved visual contrast and powder adhesion. Full article

Using optical spectroscopy methods including absorption in the UV-VIS, FTIR, Raman, and fluorescence, the spectra of 25 different Baltic amber samples were measured, and the ability of each method to distinguish between thermally modified and naturally aged material was analyzed. The natural ambers studied are characterized by a wide range of spectral properties: the position of the transmission edge in the UV-VIS spectra, the absorbance ratios of the C-H and C=O groups in the IR spectra, a difference of approximately 20% in the fluorescence intensity level, and differences in the band ratios in the C=C and C-H bonds in the Raman spectrum. Spectral studies were carried out on samples of natural and thermally modified amber at temperatures of 100, 150, and 200 °C for 2–8 h. Drastic changes occur at temperatures above 150 °C: the color changes to dark brown, the UV-VIS transmission edge shifts, the absorbance of the C=O group increases, the absorbance intensity of the C=C bond decreases, and fluorescence disappears. In some special cases, fluorescence methods allow for the unambiguous distinction of amber from different geographical regions (e.g., Baltic and Dominican). Spectroscopic methods can distinguish natural amber from thermally modified amber only for large changes in the spectrum at temperatures of 150–200; for smaller changes, the differences between individual samples of natural amber may be greater than in the case of thermal modification. Full article

Co(II) complexes have shown promising applications as single-molecule magnets (SMMs) in quantum computing and structural biology. Deciphering the Co(II) complexes may facilitate the development of SMM materials. Structural optimizations and calculations of chemical and magnetic properties were performed for Co(II) complexes with a tripodal tetradentate phenolate-amine ligand using MP2/aug-cc-pvdz, MP2/Def2svp, and CASSCF/Def2svp methods. The Second Order Perturbation Theory Analysis of Fock Matrix in NBO Basis unravels that Co(II) ions form unusual coordinate quasi-double bonds with ligand oxygen donor atoms, and the bond strengths range from 142.01 kcal/mol to 167.36 kcal/mol but lack further spectrometric evidence. The average 151.70 kcal/mol of the Co(II-O coordinates quasi-double bonds are formed mainly by two lone pairs of electrons from the ligand phenolate donor oxygen atoms. Dispersion forces contribute 24%, 28%, 27%, and 31% to the Co(II)-ligand interaction. Theoretical results of ZFS D, transversal ZFS E, and g-factor agree well with the experimental values. Magnetic susceptibility parameters calculated based on 5 doublet roots account for 85% of results computed 40 doublet roots are specified. These insights may aid in the rational design of SMM materials and Co(II) porphyrin fullerene conjugate for CO₂ electroreduction with superior magnetic properties. Full article

Background/Objectives: Composite dental restorations are continuously exposed to dietary substances, which may compromise their structural integrity. This study aimed to assess the chemical and mechanical effects of coffee, red wine, and Coca-Cola on two widely used commercial resin composites, Herculite Ultra XRV and Omnichroma. Methods: Forty disk-shaped specimens (20 per material) were immersed for 10 days in the selected beverages. Changes in chemical composition were analyzed using Fourier Transform Infrared (FTIR) and Raman spectroscopy, while Vickers microhardness testing evaluated surface hardness. Results: FTIR and Raman analyses revealed that coffee and red wine caused the most substantial chemical degradation, particularly in carbonyl (C=O), aromatic (C=C), and siloxane (Si–O–Si) groups. Herculite XRV demonstrated higher chemical stability, while Omnichroma showed more pronounced molecular degradation. In contrast, microhardness testing indicated that Omnichroma maintained better surface hardness compared to Herculite XRV after exposure. Across all solutions, Coca-Cola induced the least effect. Conclusions: The tested beverages significantly affected both the chemical and mechanical properties of the resin composites. Omnichroma exhibited superior mechanical durability, while Herculite XRV showed greater resistance to chemical degradation. These results highlight the importance of material composition in restorative dentistry and support the development and selection of composites with improved resistance to acidic and staining agents to ensure long-term clinical performance. Full article

To tackle the degradation of sealing performance in nitrile butadiene rubber (NBR) seals due to material aging during long-term service, this study integrates experimental and molecular simulation methods to elucidate the aging mechanism. Experimental results reveal that the contents of C=C and C=O functional groups significantly decrease during aging, accompanied by enhanced hydrophobicity and increased crosslink density of NBR, indicating that crosslinking reactions dominate the aging process with the participation of C=C and C=O groups. Quantum mechanics (QM) and molecular dynamics (MD) simulations further demonstrate that α-H, C=C, and C≡N groups are preferentially oxidized due to their low bond energies. The oxidation of NBR generates unstable epoxy intermediates, which undergo chain scission to form ketones, aldehydes, and ultimately crosslinked structures. Using a multi-dimensional evaluation system based on bond dissociation energy (BDE), solubility parameter (Δδ), and migration coefficient (MSD), four antioxidants (4010NA, 4010, MC, and BHT) were screened. BHT emerges as the optimal choice, exhibiting superior free radical scavenging ability (BDE = 346.3 kJ/mol), good matrix compatibility (Δδ = 2.95), and anti-migration properties. The MD-based screening method established herein provides a theoretical basis for designing antioxidant systems in high-performance rubber materials, facilitating the development of advanced rubber products. Full article

A. dracunculus L., is a species of traditional Chinese medicine herbs, widely distributed northwestern China and used as antidiabetic, antibacterial etc., but the active compounds and their abundance have not been systematically investigated. This research focused on the following: (i) optimizing polyphenol extraction/purification from A. dracunculus; (ii) UPLC-QE-based profiling of polyphenolic composition; (iii) FT-IR-assisted structural elucidation; and (iv) functional assessment of antioxidant and antibacterial properties. The results showed that the highest extraction yield of crude polyphenols of A. dracunculus (CPA) reached 5.02 ± 0.04% at an ethanol concentration of 70% of 70 °C with a solid-to-liquid ratio of 1:20 (g/mL). The D101 macroporous resin is the best one for polyphenolpurification of A. dracunculus (PPA), with a purification efficiency of 60.48 ± 1.87%. UPLC-QE analysis identified 36 polyphenolic compounds in PPA, in whic the content of protocatechuic acid is the highest at 1338.05 ± 1.83 ng/mg. The absorption peaks at 1691 cm⁻¹ (carbonyl, C=O), 1605 cm⁻¹and 1518 cm⁻¹ (aromatic C=C), as well as 1275 cm⁻¹ and 1369 cm⁻¹ (C-O stretching), indicated the presence of phenolic acids, flavonoids and tannins in PPA by FT-IR. PPA exhibited significant antioxidant activity, which reached 81.73 ± 1.43% for DPPH, 87.11 ± 1.57% for hydroxyl and 85.74 ± 1.52% for ABTS+. It also demonstrated strong antibacterial activity against nine common pathogenic bacteria, but not to Escherichia coli. A. dracunculus polyphenols demonstrate potent bioactive properties, suggesting potential applications in functional foods and natural preservatives. Full article

Investigating viable processes for the use of lignocellulosic biomass in clean fuels and high-value-added chemical products is essential for sustainable development. Large amounts of lignin are available every year as by-products of the paper and biorefinery industries, causing a series of problems, particularly environmental ones. Its structure and composition make lignin compatible with the concept of sustainability, since it can be used to produce new chemical products with high added value. As such, this study aims to extract lignin from green coconut fiber (LIG), with the subsequent impregnation of a sodium-octanoate-based surfactant (LIG-SUR), and determine its applicability as an adsorbent for removing copper ions from synthetic waste. To this end, the green coconut fiber lignocellulosic biomass was initially subjected to alkaline pre-treatment with 2% (w/v) sodium hydroxide in an autoclave. Next, the surface of the lignin was modified by impregnating it with sodium octanoate, synthesized from the reaction of octanoic acid and NaOH. The physical and chemical traits of the lignin were studied before and after surfactant impregnation, as well as after copper ion adsorption. The lignin was analyzed by X-ray fluorescence (XRF), Fourier transform infrared (FTIR) and scanning electron microscopy (SEM). The adsorption tests were carried out using lignin pre-treated with surfactant in a batch system, where the effects of pH and adsorbent concentration were investigated. XRF and SEM analyses confirmed surfactant impregnation, with Na₂O partially replaced by CuO after Cu²⁺ adsorption. FTIR analysis revealed shifts in O–H, C–H, C=O, and C=C bands, indicating electrostatic interactions with lignin. Adsorption kinetics followed the pseudo-second-order model, suggesting chemisorption, with equilibrium reached in approximately 10 and 60 min for LIG-SUR and LIG, respectively. The Langmuir model best described the isotherm data, indicating monolayer adsorption. LIG-SUR removed 91.57% of Cu²⁺ and reached a maximum capacity of 30.7 mg·g⁻¹ at 25 °C and a pH of 6. The results of this research showed that pre-treatment with NaOH, followed by impregnation with surfactant, significantly increased the adsorption capacity of copper ions in solution. This technique is a viable and sustainable alternative to the traditional adsorbents used to treat liquid waste. In addition, by using green coconut fiber lignin more efficiently, the research contributes to adding value to this material and strengthening practices in line with the circular economy and environmental preservation. Full article

Achieving efficient electrocatalytic oxidation of cellulose-derived biomass is a pivotal strategy for advancing bioenergy utilization and achieving carbon neutrality. This study addresses the challenges of low conversion efficiency caused by cellulose’s high crystallinity and excessive energy consumption in conventional processes by proposing a novel integrated system combining solid heteropoly acid catalytic pretreatment and electrocatalytic oxidation. By preparing the (C₁₆TA)H₂PW solid acid catalyst, we successfully achieved hydrolysis of microcrystalline cellulose under 180 °C for 60 min, attaining a glucose yield of 40.1%. Furthermore, a non-noble metal electrocatalyst system based on foam copper (CuF) was developed, with the Co₃O₄/CuF electrode material demonstrating a Faradaic efficiency of 85.3% for formate production at 1.66 V (vs. RHE) in 1 mol L⁻¹ KOH electrolyte containing the pretreated cellulose mixture, accompanied by a partial current density of 153.2 mA cm⁻². The mechanism study indicates that hydroxyl radical-mediated C-C bond selective cleavage dominates the formate generation. This integrated system overcomes the limitations of poor catalyst stability and low product selectivity in biomass conversion, offering a sustainable strategy for green manufacturing of high-value chemicals from cellulose. Full article