Search Results (246)

Microbial exopolysaccharides (EPS) are structurally diverse biopolymers with ecological and biotechnological relevance due to their physicochemical and functional properties, including emulsification, metal chelation, and contributions to biofilm formation. In this study, an EPS-enriched extracellular fraction (EPS-EF) produced by Vreelandella zhaodongensis BS253, isolated from the Brazilian Pantanal, was characterized using an integrated approach combining microscopic, physicochemical, molecular, genomic, and transcriptomic analyses. Morphological and structural profiling by microscopy revealed a highly porous, reticulated web-like supramolecular network. The EPS-EF exhibited cation-dependent colloidal stability, with turbidity decreasing by approximately 95% after divalent-cation chelation. The emulsification index after 24 h (E24) against kerosene reached approximately 67%, and the surface tension of water was reduced to approximately 45 mN/m, with an apparent surface-tension inflection (STI) near 10.7 mg/mL. X-ray diffraction (XRD) revealed a predominantly amorphous profile with discrete crystalline reflections. Thermogravimetric analysis (TGA) demonstrated thermal stability with a multi-step degradation profile and a maximum decomposition rate centered at 280 °C. CHNS/O and FTIR were consistent with a carbohydrate-associated, nitrogen-poor molecular profile containing carbonyl/carboxylate and glycosidic functionalities. UHPLC–ESI–QTOF–MS/MS resolved a reproducible set of oligomeric features across four chromatographic zones, without establishing monosaccharide composition, together with minor hydrophobic features tentatively associated with lipid-related compounds. One-dimensional ¹H NMR provided complementary molecular-fingerprint information, but the primary structure remains unresolved. EPS-EF material analysis may also include contributions from co-extracted components because the analyzed material is an enriched extracellular fraction rather than a chemically homogeneous polysaccharide. Genome mining and targeted RNA-seq analysis of 47 EPS-associated genes identified candidate pathways for precursor metabolism, glycan assembly, and export. Collectively, these findings indicate that V. zhaodongensis BS253 produces an ionic-sensitive EPS-EF with emulsifying activity and support a working hypothesis for EPS-EF biosynthesis and export. Full article

Three series of benzylidene cinnamoylhydrazides (21 compounds) were synthesized and evaluated for cytotoxic activity against malignant and non-malignant cell lines. Among the compounds tested, 2d and 3c were the most active against Jurkat and CEM leukemia cells, with CC₅₀ values in the low micromolar range. Both compounds were more potent against these leukemia cell lines than the reference compounds 5-fluorouracil, curcumin, and melphalan. However, 2d and 3c showed only modest selectivity over non-malignant Hs27 fibroblasts, with selectivity index values of 2.50 and 2.09, respectively, in CEM cells. Further studies in CEM cells showed that treatment with 2d and 3c was associated with apoptosis, caspase activation, increased ROS accumulation, mitochondrial membrane depolarization, and changes in cell-cycle distribution, with the most notable change being an increase in the sub-G0-G1 population. The compounds also showed growth-inhibitory and cytotoxic activity against several cell lines in the NCI-60 panel. Semi-empirical PM3 calculations suggested possible relationships between cytotoxic activity, electronic polarization of the α,β-unsaturated carbonyl system, and molecular dimensions. However, these relationships were not consistent across the series and should be considered preliminary. Overall, 2d and 3c represent useful hit structures for further investigation, although additional structural optimization and biological studies will be needed to improve their selectivity and better define their mechanisms of action. Full article

This study investigated whether black soldier fly larvae meal (BSFL; Hermetia illucens L.) produced on polyphenol-rich agro-industrial by-products could enhance broiler meat lipid quality and oxidative stability during refrigerated storage. A total of 200 one-day-old Arbor Acres broilers were allocated to five dietary treatments: control diet, 5% standard full-fat BSFL meal, 10% standard full-fat BSFL meal, 10% full-fat BSFL meals produced on olive leaf and spent tea residues, and 10% defatted BSFL meal. Compared with standard full-fat BSFL meal, the olive leaf–spent tea BSFL meal showed markedly higher total phenolic content (6.74 vs. 1.82 mg GAE/g DM), DPPH radical-scavenging activity (54.80 vs. 22.40%) and ABTS antioxidant capacity (38.20 vs. 15.60 umol TE/g DM), together with lower peroxide value (1.46 vs. 2.38 meq O₂/kg lipid) and TBARS (0.24 vs. 0.39 mg MDA/kg meal). Also, when compared with 10% standard full-fat BSFL meal, the olive leaf–spent tea BSFL meal improved final body weight (2592.8 vs. 2511.6 g) and feed conversion ratio (1.53 vs. 1.58). Breast meat from this group contained higher oleic acid (40.52 vs. 37.48%) and a-linolenic acid (1.72 vs. 1.29%), while showing a lower n-6/n-3 ratio (11.81 vs. 14.49) and thrombogenicity index (0.78 vs. 0.92). After 10 days of refrigerated storage, breast meat from birds fed the polyphenol-enriched BSFL meal showed markedly lower oxidative deterioration, as indicated by reduced TBARS values (0.60 vs. 1.12 mg MDA/kg), protein carbonyl formation (2.16 vs. 3.35 nmol/mg protein) and hexanal abundance (5.10 vs. 11.90 a.u.; internal-standard-normalized peak area). This treatment also better-preserved redness, as reflected by higher CIE values (3.52 vs. 2.40), compared to the control group. Overall, these results suggest that substrate-tailored BSFL meal may serve as a functional feed ingredient for improving the lipid quality of broilers’ breast meat and delaying oxidation-driven quality deterioration during refrigerated storage. Full article

This study aimed to elucidate the characteristics of protein changes and their relationship with physicochemical properties during the quality deterioration of refrigerated Northern Pike (Esox lucius). We employed tandem mass tag (TMT)-based quantitative proteomics, combined with physicochemical indicators, including surface hydrophobicity, carbonyl content, sulfhydryl content, and myofibrillar fragmentation index (MFI), to systematically analyze protein alterations during cold storage. The results showed that with prolonged cold storage, the surface hydrophobicity, carbonyl content, and MFI of Northern Pike samples exhibited an increasing trend, whereas the sulfhydryl content decreased. Proteomic analysis identified a total of 563 differentially expressed proteins (DEPs) between fresh and cold-stored states, of which 293 were upregulated and 270 were downregulated. Furthermore, by integrating COG/KOG functional classification, subcellular localization, and GO enrichment analysis, the functional characteristics of the DEPs and their potential involvement in biological processes were systematically characterized. Correlation analysis revealed that six DEPs were significantly correlated with the changes in physicochemical indices of Northern Pike during cold storage, namely fructose-bisphosphate aldolase encoded by ALDOA, Nesh-SH3 domain-target protein, keratin, neurofilament heavy polypeptide, serine/arginine repetitive matrix protein 2-like, and asymmetrical bis(5′-nucleosidyl) tetraphosphatase. By integrating analyses of differentially abundant proteins and protein oxidation, this study suggests potential molecular mechanisms potentially responsible for quality loss in northern pike under chilled storage, offering a theoretical foundation for its preservation and quality assessment. Full article

Glycation and reactive carbonyl stress are protein-modifying processes associated with skin aging, but how they alter local tissue mechanics and deformation-prone behavior remains unclear. Here, reconstructed human epidermis (RHE) and three-dimensional (3D) collagen gels were used as epidermal-like and collagen-rich skin surrogate compartments. Nanoindentation mapping showed that accelerated glycation and carbonyl stress increased the effective Young’s modulus and stiffness heterogeneity in both models, with 2.34–5.85-fold increases in the mean modulus and 1.09–1.31-fold increases in normalized neighbor contrast across four treatment–model combinations: glycated RHE, glycated 3D collagen gel, carbonyl-stressed RHE and carbonyl-stressed 3D collagen gel. Nanoindentation-derived stiffness profiles were incorporated into reduced-order virtual bilayer nonlinear post-buckling simulations. Under imposed end-shortening strains of 1%, 5%, and 10%, glycation- and carbonyl-stress-informed bilayers showed increased predicted peak curvature and localized folding index values. Profile-control simulations were then used to separate average stiffening from spatial stiffness variation. Uniform-mean profiles failed to reproduce the curvature localization response, whereas heterogeneity-preserving mean-matched profiles retained elevated curvature-based outputs. These findings suggest that spatial stiffness heterogeneity, rather than stiffening alone, contributes to predicted curvature localization in skin surrogate bilayers. Beyond mechanistic insight, the nanoindentation–simulation workflow may provide a mechanics-based readout for evaluating prospective cosmetic interventions. Full article

This study investigates the effect of Arundodonax L.-derived lignin on the rheological behaviour, mechanical performance and oxidative ageing resistance of bitumen. Arundo donax is a fast-growing invasive grass with high lignin content, representing a promising sustainable biomass source for bitumen modification. Lignin was extracted via the Acid Detergent Lignin method, yielding a fine powder (50–300 μm). The incorporation of 6 wt% lignin into a 35/50 paving-grade bitumen induced significant changes in binder behaviour. Infrared spectroscopy (FTIR) confirmed the polyaromatic and oxygenated nature of lignin and indicated that its interaction with bitumen is primarily physical, involving polar intermolecular interactions rather than chemical bonding. Lignin modification significantly increased stiffness, elasticity, and rutting resistance, as evidenced by higher softening point, complex modulus, and recovery after creep loading. Furthermore, FTIR analysis confirmed a reduced susceptibility to oxidative ageing, demonstrated by lower increases in carbonyl and sulfoxide indexes after ageing. This suggests distinct antioxidant activity associated with the phenolic structures of lignin. Despite these benefits, severe long-term ageing led to a marked reduction in fatigue life, ductility, low-temperature cracking resistance, and adhesive properties. Overall, these results demonstrate that Arundo donax-derived lignin is a promising sustainable modifier for bitumen, though optimisation of the dosage and blending conditions is necessary to balance durability against long-term fracture performance. Full article

Oxidative stress is a major constraint limiting animal health and productive performance by disrupting redox homeostasis, mitochondrial function, intestinal integrity, and mineral metabolism. Agronomic biofortification of forage with essential trace minerals represents a promising nutritional strategy; however, its physiological and molecular mechanisms remain poorly understood. This study evaluated the effects of dietary zinc–iron (Zn–Fe) biofortified alfalfa on oxidative stress, antioxidant defense, mineral transport, mitochondrial bioenergetics, intestinal barrier integrity, inflammatory responses, tissue mineral deposition, and growth performance in guinea pigs. Forty-eight male guinea pigs were allocated to six experimental groups according to dietary treatment (control, Zn-biofortified alfalfa, or Zn–Fe biofortified alfalfa) and oxidative stress status. Oxidative biomarkers, antioxidant enzyme activities, inflammatory mediators, mineral concentrations, targeted RT–qPCR, mitochondrial function, intestinal histomorphology, and multivariate physiological analyses were performed. Zn–Fe biofortified alfalfa markedly reduced reactive oxygen species, malondialdehyde, protein carbonyls, 8-hydroxy-2′-deoxyguanosine, advanced oxidation protein products, and the oxidative stress index while significantly increasing superoxide dismutase, catalase, glutathione peroxidase, total antioxidant capacity, and the glutathione redox ratio. Targeted gene-expression analysis demonstrated coordinated upregulation of intestinal mineral transporters (ZIP4, DMT1, and MT1), activation of the Nrf2 antioxidant pathway, increased expression of mitochondrial regulatory genes, and suppression of inflammatory mediators. These molecular responses were accompanied by improved ATP production, mitochondrial membrane potential, respiratory-chain activity, preservation of intestinal villus architecture, enhanced expression of tight-junction proteins, increased tissue Zn and Fe deposition, superior feed efficiency, and greater body weight gain. Integrated physiological analyses consistently identified the Zn–Fe biofortified treatment as the highest-performing physiological phenotype, indicating coordinated adaptation across multiple biological systems. These findings demonstrate that Zn–Fe biofortified alfalfa enhances oxidative stress resilience through simultaneous regulation of mineral transport, antioxidant defense, mitochondrial bioenergetics, intestinal barrier integrity, and systemic physiological performance. Agronomic biofortification of forage therefore represents a promising nutritional strategy for improving animal health, mineral utilization, and productive efficiency under oxidative stress. Full article

Ultraviolet (UV) radiation in high-altitude regions critically accelerates asphalt aging by inducing surface oxidation, molecular chain scission, and loss of low-temperature crack resistance. However, systematic comparisons of the macro-rheological and micro-chemical evolution between base asphalt and SBS-modified asphalt under UV aging remain insufficient. In this study, two types of asphalt (virgin and SBS-modified) were subjected to three aging protocols, namely short-term thermal oxidation (RTFOT), long-term thermal oxidation (PAV), and equivalent UV radiation for 13 h, 26 h, and 37 h. Low-temperature rheological properties were evaluated using the bending beam rheometer (BBR), while atomic force microscopy (AFM) and Fourier transform infrared spectroscopy (FTIR) characterized the microstructural and chemical changes. The results show that long-term thermal oxidation causes the most severe deterioration of low-temperature rheological performance, whereas short-term thermal oxidation and 13 h UV aging exhibit comparable effects. For SBS-modified asphalt, extending UV exposure from 13 h to 37 h leads to progressive stiffening and loss of relaxation capacity at −12 °C and −18 °C. However, the m-value shows a non-monotonic response at −24 °C, indicating that the temperature dependence of UV aging is more complex at extremely low temperature. For base asphalt, aging promotes the formation and subsequent agglomeration of bee-like structures. For SBS-modified asphalt, the sulfoxide index increases monotonically, while the carbonyl index first increases and then decreases. Although 13 h UV aging and RTFOT produce similar macroscopic outcomes, their mechanisms differ fundamentally, where UV aging is hypothesized to act primarily via photon-induced bond scission, whereas thermal oxidation proceeds through radical chain reactions. Full article

Organic thin-film transistors based on dinaphtho[2,3-b:2′,3′-f]thieno[3,2-b]thiophene (DNTT) are attractive for low-cost, large-area electronics, but in unencapsulated devices, atmospheric oxidation generates charge traps whose electronic character—which product traps holes and which traps electrons—has not been mapped systematically. Here, 39 oxygen- and hydroxyl-related defect identities of DNTT are screened with the semi-empirical GFN2-xTB method, complemented by an a priori frontier reactivity index, and classified by the sign of the frontier-level shift. This sign obeys a simple rule: a net $\pi$-donating hydroxyl raises the HOMO and yields a hole trap, whereas a net $\pi$-accepting carbonyl or quinone lowers the frontier levels and yields a deep electron trap. Hybrid density-functional theory (B3LYP/def2-TZVP) confirms the sign rule and the ordering of the shifts across all closed-shell defect classes. The rule provides a compact, defect-level rationalisation of the well-known asymmetry whereby p-type acenes tolerate air far better than n-type ones. Finally, a hole trap of about 0.255 eV, measured by deep-level transient Fourier spectroscopy, is shown to be consistent with a hydroxyl-related origin, without claiming a unique microscopic assignment. Full article

This study provides an in-depth investigation of the influence of calcium carbonate (CaCO₃) filler on the mechanical performance and aging resistance of polyvinyl chloride (PVC)-based composites. PVC/CaCO₃ composites containing 2.5, 5, and 7.5 wt% of CaCO₃ were subjected to accelerated aging under combined ultraviolet (UV) irradiation and thermal stress for up to 1248 h. The key mechanical properties of specimens —tensile strength and elongation at break—were measured before and after aging. Changes in surface morphology, coloration, hydrophobicity, and chemical composition were characterized using scanning electron microscopy (SEM-EDS), X-ray spectroscopy, atomic force microscopy (AFM), contact angle measurements, and carbonyl index calculation to quantify relationships between the structural and physical properties of the specimens and aging conditions. The results reveal a significant correlation between filler content and the mechanical behavior of aged specimens, highlighting the potential of CaCO₃ reinforcement not only to improve the retention of mechanical properties but also to increase the service life of PVC-based insulation compounds. Full article

The combined pretreatment of ultrasound irradiation, urea, and sodium hydroxide was explored to increase the extraction and delignification of cellulose from spent coffee grounds (SCGs), shortening the extraction time. The impacts of different experimental conditions, namely alkali concentration (5 vs. 10%), urea addition (0 vs. 3%), and ultrasound aid (30 min, 40 kHz, 150 W), on the physicochemical characteristics of the extracted cellulose were determined. The first characteristic of the raw biomass was its high lignin content (30.4%), necessitating a rigorous delignification process. To confirm this, samples were further analyzed by FTIR, XRD, TGA, and SEM. The successful elimination of non-cellulosic material, as indicated by the disappearance of the carbonyl stretch at 1730 cm⁻¹ and attributed to hemicellulose and pectin, was confirmed by FTIR. The XRD results revealed that while the individual application of ultrasound yielded the highest apparent crystallinity index (64.5% for sample B), the synergistic low-alkali combination with urea (sample F) resulted in a lower, controlled crystallinity index (56.2%). This indicated that the coexistence of urea and ultrasound induces significant fiber swelling and localized hydrogen-bond disruption, as well as highly efficient chemical purification. The thermal analysis revealed that all samples had high thermal stability with a maximum degradation temperature (T_max) between 316 and 322 °C, which can be used in composites. The process was visually confirmed by morphological analysis carried out under SEM, which revealed a progressive surface erosion of the compact lignocellulosic matrix into cellulose-rich samples treated with ultrasound. Full article

The qualitative evolution of SARA fractions during asphalt binder aging is well established, but further validation is needed to demonstrate whether automated HPLC-SARA analysis can provide repeatable compositional indicators for systematic aging studies. In this work, the applicability of a previously optimized automated high-performance liquid chromatography (HPLC) workflow for saturate, aromatic, resin, and asphaltene (SARA) fractionation was evaluated for the monitoring of thermo-oxidative aging. Four penetration-grade asphalt binders were subjected to short-term aging and multiple long-term aging cycles, and the resulting SARA distributions were used to calculate the colloidal instability index (I_c). Fourier-transform infrared spectroscopy (FTIR) was used as an independent reference technique to evaluate carbonyl and sulfoxide oxidation indices. The automated HPLC-SARA method provided repeatable compositional indicators across all asphalt binders and aging conditions. As expected, aromatics progressively decreased whereas asphaltenes increased, while saturates showed only limited variations and resins behaved as an intermediate operational fraction. More importantly, I_c increased consistently with aging and showed a strong correlation with the FTIR carbonyl index (R² = 0.84 when all asphalt binders and aging conditions were considered), whereas the sulfoxide index showed a more asphalt binder-dependent response. These results demonstrate that automated HPLC-SARA analysis can provide aging-sensitive compositional and colloidal indicators that are chemically consistent with independent FTIR oxidation markers. The proposed workflow represents a complementary tool for asphalt binder aging research and may support future studies aimed at linking compositional evolution with rheological and durability-related properties. Full article

Frozen storage is widely used to preserve shrimp products, but the multiscale mechanisms underlying quality deterioration in giant freshwater prawn remain insufficiently understood. This study investigated changes in water retention, oxidative stability, muscle structure, and protein conformation in Macrobrachium rosenbergii stored at −20 ± 2 °C for 0, 1, 3, and 5 months. Thawing and cooking losses, water-holding capacity, freshness and oxidation indices, texture, histology, low-field nuclear magnetic resonance, Fourier transform infrared spectroscopy, and intrinsic fluorescence were comprehensively evaluated. After 5 months, thawing loss increased from 8.21% to 12.51%, cooking loss increased by 55.0%, and water-holding capacity decreased from 85.45% to 68.46%. The total volatile basic nitrogen, protein carbonyl content, thiobarbituric acid reactive substances (TBARS; 0.186 to 0.528 mg MDA/kg), and myofibril fragmentation index increased progressively, while free sulfhydryl and salt-soluble protein contents declined. Shear force, hardness, cohesiveness, gumminess, and chewiness also decreased, accompanied by muscle fiber separation and an increase in white void area from 0.04% to 3.46%. Low-field nuclear magnetic resonance revealed decreases in the short-relaxation P₂b and P₂1 populations and an increase in the dominant P₂2 population, indicating relative water-population redistribution. Meanwhile, α-helix content decreased from 18.83% to 16.28%, β-sheet content increased from 25.05% to 28.22%, and maximum fluorescence intensity decreased by 31.9%. These coordinated changes suggest that prolonged frozen storage weakened the myofibrillar network through water redistribution, lipid and protein oxidation, protein fragmentation, conformational rearrangements, and tissue disruption. The findings provide a multiscale basis for developing water-retention and quality-control strategies for frozen giant freshwater prawn. Full article

The global proliferation of microplastics demands sustainable remediation alternatives to energy-intensive conventional disposal methods, shifting research focus toward polymer-degrading microbial communities within the “plastisphere.” The primary objectives of this study are twofold: first, to systematically decode the sequential biophysical mechanisms underlying microplastic colonization and enzymatic degradation; and second, to establish an empirically validated, scalable treatment framework that employs both a novel biological isolate and a hybrid engineering architecture. Experimentally, we investigate the multi-stage colonization process and demonstrate that “Phase Zero” conditioning films modulate the surface zeta potential (ζ) to anchor pioneer r-strategists. To evaluate degradative efficacy under accelerated conditions without abiotic pretreatment, the newly isolated carp gut strain Hafnia paralvei UUNT_MP29 was exposed to pristine low-density polyethylene (LDPE) and polystyrene (PS). Over a 16-day biotic incubation period, structural and chemical alterations were distinctly polymer-specific: bacterial action on the polyolefin LDPE yielded a Carbonyl Index of 0.4594 and a 10.95 °C reduction in thermal stability (T_max), whereas the aromatic PS matrix exhibited a Carbonyl Index of 0.3235 alongside a 10.80 °C decrease in T_max, with both substrates showing intense surface pitting. To standardize these complex tracking metrics across the field, a universal four-pillar Biodegradability Index (BI) was formulated. Based on these findings, we recommend an immediate transition from passive waste containment to a closed-loop engineering approach. Specifically, we propose integrating an artificial intelligence (AI)-managed hybrid bioprocess configuration that couples Advanced Oxidation Processes (AOPs) with Membrane Bioreactors (MBRs). This dual-stage configuration is recommended to overcome polyolefin crystallinity, accelerate stoichiometric mineralization, and actively mitigate additive-mediated toxicity at the industrial scale, providing a vital blueprint for the circular bio-economy. Full article

Aging of Styrene–butadiene–styrene (SBS)-modified asphalt accelerates the degradation of both the SBS polymer network and asphalt components, resulting in deterioration of the durability of asphalt concrete. This study investigates the use of zinc diethyldithiocarbamate (ZDC), a multifunctional antioxidant, in SBS-modified asphalt to improve its aging resistance. Physical property tests, dynamic rheological analysis, multiple stress creep recovery (MSCR) and Fourier transform infrared spectroscopy (FTIR) assays were conducted to evaluate the rheological and chemical properties of asphalt binders before and after thermo-oxidative and UV aging. The results indicate that the incorporation of ZDC improved the deformation resistance and elastic recovery of SBS-modified asphalt. After aging, the ZDC/SBS composite-modified asphalt exhibited lower performance change rate than conventional SBS-modified asphalt, indicating enhanced resistance to permanent deformation and aging-induced damage. FTIR analysis demonstrated that ZDC effectively inhibited the formation of oxygen-containing functional groups during aging, suggesting suppressed oxidative reactions within the asphalt binder. The 5% ZDC dosage reduces the carbonyl index of SBS-modified asphalt by 36.48% after thermo-oxidative aging, and by 21.89% after UV aging, showing a stronger chemical inhibition effect on thermo-oxidative reactions. From the perspective of rheological performance stability, ZDC lowers the variation amplitude of non-recoverable creep compliance by 35.32% before and after thermo-oxidative aging and 41.46% before and after UV aging, and delivers a more prominent mitigating effect on property fluctuations triggered by UV aging. This indicates that ZDC exerts differentiated anti-aging mechanisms on thermo-oxidative and UV aging, with considerable potential to improve the comprehensive aging resistance of polymer-modified asphalt binders. Full article