Search Results (507)

Existing colorimetric sensing strategies based on gold nanoparticles (AuNPs) are largely limited to the detection of free metal ions, leaving metal–organic complexes widely present in real water bodies undetectable. Herein, we develop a simple colorimetric method based on the anti-aggregation effect of bare AuNPs for the simultaneous detection of free Cr³⁺ and its organic complexes. Tetrabutylphosphonium bromide (TPB) dissociates into phosphonium cations ([P(C₄H₉)₄]⁺), which neutralize the negatively charged surface of AuNPs via electrostatic attraction, thereby inducing particle aggregation and a color change from wine-red to blue. Under strongly alkaline conditions, Cr³⁺ converts to negatively charged [Cr(OH)₆]³⁻ species. These anionic species then compete with the AuNPs for the phosphonium cations, blocking the aggregation process and preserving the wine-red color. This competitive mechanism is further extended to the detection of Cr³⁺-EDTA, Cr³⁺-tartrate, and Cr³⁺-oxalate complexes, as they also transform into [Cr(OH)₆]³⁻ under alkaline conditions. Without the need for tedious surface modification, the proposed method is simple to operate and exhibits excellent sensitivity and selectivity for both free and complexed Cr³⁺ in real water samples. It thus provides a reliable analytical tool for monitoring chromium pollution in environmental waters. Full article

Cement-based grouting materials with a high water-to-cement ratio are susceptible to connected pore development, chloride ingress, and mechanical degradation in chloride-bearing groundwater and marine environments. To improve resistance to NaCl attack, this study compared an unmodified cement-based grouting material (NC) with a polyacrylate-emulsion-modified material (PA). Mechanical properties, surface wettability, pore structure, phase assemblage, thermal behavior, functional groups, and microstructure were investigated under different NaCl concentrations (0%, 5%, 10%, and 15%) and immersion durations (28 and 90 d). This study systematically evaluates the coupled evolution of mechanical strength retention, surface wettability, pore structure, chloride-bearing phases, and microstructure in a bulk PA-emulsion-modified high-water-to-cement-ratio grouting material under graded NaCl exposure. The results showed pronounced concentration- and time-dependent effects. Low NaCl concentrations were associated with continued hydration and reaction-product filling, whereas higher concentrations and prolonged exposure led to pore coarsening and strength loss. PA modification improved the mechanical stability of the material in NaCl environments. After 90 d of immersion in 15% NaCl, the compressive and flexural strengths of the PA group were 23.60% and 22.53% higher than those of the NC group, respectively, while the corresponding strength-retention ratios were higher by 9.06 and 10.40 percentage points. Contact-angle and MIP results showed that PA reduced surface wettability and mercury-accessible porosity. After 15% NaCl exposure, the contact angle of the PA group remained 72.5°, compared with 40.1° for the NC group, while the porosity decreased from 38.11% in the NC group to 30.98% in the PA group. XRD, TG-DTG, and FTIR analyses indicated the formation and evolution of Friedel’s salt or other chloride-bearing AFm phases after NaCl exposure. Combined with SEM observations, the results indicate that PA mitigates NaCl-induced deterioration through reduced surface wettability, refined pore structure, regulated chloride-bearing product distribution, and improved matrix integrity. Overall, the findings establish a coupled surface–pore–phase–microstructure framework for understanding the enhanced NaCl resistance of PA-modified cement-based grouting materials. Full article

Nonlinear optical (NLO) active chromophores and their applications in photothermal therapy (PTT) demonstrate great potential in modern theragnostics, owing to their efficient light–matter interactions. A recognized D–π–A chromophore, FTC-3f, which is reported to exhibit a high photothermal conversion efficiency (~51.11%), was structurally modified with various spacers and acceptors to elucidate enhanced PTT and NLO behavior through DFT and TD-DFT simulations. Molecular geometries were optimized at the B3LYP/6-31G (d, p) level. Their electronic properties, charge separation, and efficient transition pathways were analyzed using frontier molecular orbitals (FMOs), density of states (DOS), UV–visible spectroscopy, photon-induced electron transfer (PET), and transition density matrix (TDM) analysis. Among all the derivatives, D4 exhibited the smallest HOMO–LUMO energy gap (1.701 eV). The highest first-order hyperpolarizability (β) values are found for D4 (1.50 × 10⁵ in the gas phase, 7.40 × 10⁵ in water, 3.06 × 10⁵ in benzene solvent). The β_HRS is found to be in the range 5.11 × 10⁴ to 2.97 × 10⁴ and DR (3.65 × 10⁵ to 4.53 × 10⁴) supports the strong NLO response and strong synergistic donor–acceptor interactions. The designed chromophores exhibit much higher SHG and EOPE responses at 532, 1907.21, and 1064 nm than FTC-3F, indicating great potential for the synthesis of effective NLO nanomedicine. Molecular docking with bovine serum albumin (PDB ID: 4F5S) and Bcl-2 (PDB ID: 2W3L) suggested favorable binding conformations, consistent with a potential for transport and apoptotic-targeting behavior. All 3D molecular descriptor parameters indicate that the designed chromophores have potential for preferential targeting in PTT. This study investigates how structural modifications of donor–π–acceptor chromophores influence their electronic, optical, nonlinear optical, and theragnostic properties, providing insights into molecular design strategies for advanced NLO-based nanomedicine applications. Full article

Fever-range hyperthermia (38–41 °C) is a typical physiological response to infection, inflammation, and systemic stress. Although increased temperatures are known to affect blood rheology and erythrocyte activity, their comprehensive impact on red blood cell (RBC) structure, mechanics, and lifespan remains incompletely understood. This review summarizes current understanding of how moderate hyperthermia affects RBC membrane structure, internal behavior, mechanical properties, and clearance cues. Evidence shows that brief exposure to febrile temperatures primarily induces reversible biophysical modifications, including heightened membrane fluidity, increased membrane fluctuations, changes in hemoglobin–water interactions, and short-term improvements in deformability. These changes reflect adaptive adjustments within the membrane–cytosol–cytoskeleton system, potentially temporarily boosting microcirculatory flow. On the other hand, prolonged or repeated heat stress causes oxidative damage, hemoglobin auto-oxidation, accumulation of membrane-bound hemoglobin, band 3 clustering, cytoskeletal restructuring, calcium imbalance, and disruption of membrane lipid asymmetry. These effects weaken membrane stability and lead to vesiculation, shape changes, increased cell fragility, altered aggregation, enhanced adhesion, and activation of clearance mechanisms. A primary focus is the transition from reversible membrane softening to permanent structural damage over time. The research supports a model in which temperature affects RBC mechanics and related membrane, cytosolic, and signaling processes that influence RBC viability. We propose interpreting febrile hyperthermia as a dynamic factor that shifts RBCs from an adaptive phase to accelerated aging and removal during prolonged heat exposure. This perspective enhances our understanding of RBC behavior during fever and systemic inflammation and underscores the role of temperature in shaping erythrocyte function and lifespan. Full article

Soil salinity is an increasing constraint to crop production, yet little is known about the responses of culantro (Eryngium foetidum), a medicinal and culinary species of high economic value, to saline conditions. This study evaluated the effects of NaCl-induced salinity (0, 40, and 80 mM) on the growth, photosynthetic performance, pigment content, and vascular anatomy of E. foetidum cultivated in vitro. After 45 days, salinity significantly reduced shoot and root length, leaf number, chlorophyll fluorescence, net CO₂ assimilation, stomatal conductance, transpiration, carboxylation efficiency, and the contents of chlorophylls a and b, and carotenoids, with the strongest effects observed at 80 mM NaCl. In contrast, leaf area, biomass accumulation, specific leaf area, and intrinsic water-use efficiency were not significantly affected. Qualitative anatomical observations indicated apparent modifications in vascular organization under saline conditions, including narrower xylem vessels and phloem disorganization. Collectively, these findings demonstrate that salinity primarily impairs photosynthetic performance and vegetative growth while inducing morphological, physiological, and apparent anatomical responses in E. foetidum cultivated in vitro. This study provides the first integrated characterization of the responses of E. foetidum to in vitro salt stress, establishing a foundation for future investigations into the physiological mechanisms underlying salinity responses in this species. Full article

Traditional cement-based foamed lightweight soils suffer from high construction costs, poor durability, and low solid waste utilization efficiency, which severely restrict their engineering application. A novel polyvinyl alcohol (PVA)-reinforced solid waste-based foamed lightweight soil is fabricated using Bayer red mud, mineral powder, and fly ash. To clarify the durability evolution mechanisms, systematic freeze–thaw cycling, long-term water immersion, and sodium sulfate erosion tests were conducted on PVA-reinforced solid waste-based, unreinforced solid waste-based, and pure cement-based specimens. The results demonstrate that the PVA-reinforced specimen achieves optimal freeze–thaw resistance with only 17.10% strength loss after 50 cycles, owing to the internal three-dimensional fiber network that restrains crack propagation and enhances matrix toughness. It also exhibits excellent long-term water immersion stability, with a mild strength increment of 4.04–10.33% after 120 days. In contrast, the CN exhibited a strength increase of 43.62%, attributed to its lower initial strength caused by incomplete hydration; however, its final strength remained between those of the other two groups. In sulfate environments, unreinforced solid waste-based specimens present superior corrosion resistance, while PVA fiber-induced interconnected pores slightly weaken sulfate erosion resistance. Microscopic analysis confirms that the generation of alunite and gypsum hydration products fundamentally causes performance discrepancies among different specimens. Different from previous studies focusing on single fiber modification or single solid waste partial replacement of cement, this study innovatively adopts a composite modification strategy of “multi-solid waste alkali-activated matrix + PVA fiber toughening”, and systematically reveals the durability evolution mechanism under multiple harsh environments. Full article

Earthquake-induced fracturing and microcrack development in subsurface strata are widely recognized as important processes influencing seepage and the hydrological behaviour of surface water bodies, particularly in tectonically active mountainous terrains. However, the hydrogeological response to repeated low-magnitude (<4) seismic events remains poorly understood. This study presents an integrated geoelectrical and remote sensing investigation of the Nagi Lake region in the Sikkim Himalaya, India, based on Vertical Electrical Sounding (VES) surveys conducted in May 2022 and March 2026, following a seismic sequence of 74 low-magnitude earthquakes recorded during February 2026. Comparative analysis of four VES profiles (VES1–VES4), supported by validatory factor analysis, reveals spatially heterogeneous changes in subsurface electrical characteristics between the two survey periods. VES1, VES2, and VES3 indicate reduced signatures of pre-existing microcracks that are consistent with sediment densification and partial sealing, whereas VES4 suggests localized development or persistence of microfractures. Because the surveys span approximately four years, these changes likely reflect the combined influence of long-term hydrogeological, environmental, and geomorphic processes, with the February 2026 seismic sequence representing one potential contributing factor rather than the sole driver. To further evaluate ground deformation, Sentinel-1A Synthetic Aperture Radar (SAR) data acquired between January 2019 and March 2026 were analysed using Persistent Scatterer Interferometric SAR (PS-InSAR). The results indicate cumulative Line-of-Sight (LOS) displacements ranging from −17.9 cm (movement away from the satellite) to +3.5 cm (movement toward the satellite) in the vicinity of Nagi Lake, reflecting localized surface deformation with millimetre-scale precision. These observations provide complementary evidence of ongoing subsurface adjustment that may promote sediment compaction and microcrack modification. Overall, the study demonstrates measurable temporal changes in the subsurface structure of the Nagi Lake area and suggests that repeated low-magnitude seismicity may contribute to subsurface restructuring alongside other environmental processes. The findings highlight the value of integrating geophysical monitoring and satellite-based deformation analysis for understanding groundwater–surface water interactions and supporting the sustainable management of vulnerable Himalayan water bodies. Full article

Reinforced concrete structures in marine environments are subjected to severe deterioration, particularly in tidal zones. The development of intrinsically hydrophobic concrete through internal modification provides a promising strategy to mitigate this challenge. This study employed sodium methyl silicate (SMS) as a hydrophobic agent to prepare recycled fine aggregate concrete (RFAC), which was subsequently subjected to accelerated indoor chloride dry–wet cycling. The deterioration behavior of RFAC and the degradation mechanism of the SMS-induced hydrophobic film during dry–wet cycling were investigated through evaluations of mechanical performance, hydrophobicity, chloride resistance, microstructure, phase composition, pore structure, chemical bonding, and functional groups. The results show that SMS improves the hydrophobicity of RFAC but inhibits its hydration process. The optimal SMS dosage for RFAC under dry–wet cycling is 9‰, which achieves a balance between hydrophobicity enhancement and pore structure optimization. Compared with ordinary RFAC, the specimen exhibits 12.9‰ and 17.6% increases in compressive strength and RDEM, respectively, after 30 cycles, accompanied by reductions of 25.8%, 52.7%, and 80.0% in peak free chloride content, chloride erosion depth, and convection zone depth, respectively. RFAC with 9‰ SMS exhibits a denser matrix with lower porosity and fewer corrosion products. SMS enhances chloride resistance mainly by reducing water transport and chloride ion ingress through hydrophobic modification. Dry–wet cycling gradually deteriorates the SMS-induced hydrophobic film through the weakening of Si-C-related structures, while the Si-O-Si framework remains relatively stable. A quantitative correlation between the contact angle and free chloride ion content is established, and the modified Lucas–Washburn equation provides a reasonable description of chloride ion penetration depth. Full article

Beech (Fagus sylvatica L.) is a widely used hardwood species whose limited natural durability and dimensional instability under moisture restrict its outdoor applications. This study investigated the effect of vacuum impregnation with corn oil (Zea mays L.), a low-cost and underexplored vegetable oil, on the surface and hygroscopic properties of beech wood. Specimens were impregnated for 30 or 60 min and characterized, together with non-impregnated controls, for weight percentage gain (WPG), dimensional change, FTIR spectra, color, hardness, surface roughness, and contact angle, before and after accelerated artificial weathering in a Xenon chamber; hygroscopic behavior was further assessed through water absorption and dimensional swelling during 24 h of water immersion. FTIR analysis confirmed effective oil penetration into the wood structure through characteristic triglyceride absorption bands. Impregnation resulted in high oil uptake (WPG > 45%) at both durations without inducing substantial dimensional change and significantly increased the contact angle and reduced water absorption (by 65%–66%) and radial and tangential swelling relative to the controls (p < 0.05), while surface hardness remained unaffected (p = 0.263). Color difference (ΔE*) after artificial weathering was significantly higher in impregnated specimens than in the controls (p < 0.001), reflecting the natural yellowish hue of the oil rather than material degradation. Overall, corn oil impregnation, applied for as little as 30 min, improved the hydrophobicity and dimensional stability of beech wood without compromising its hardness, supporting its potential as a sustainable, bio-based wood modification medium. Full article

Apigenin (API) is a flavonoid compound widely distributed in nature. The global prevalence of asthma is increasing year by year, influenced by various factors and difficult to cure completely, and new drugs and therapies are constantly emerging. Although API is a low-toxicity flavonoid compound, its poor water solubility and low bioavailability present limitations in the treatment of asthma. In this study, the structure of API was chemically modified by introducing acyl and alkyl groups while preserving its original structure. The structures were identified using FT-IR, ¹H-NMR and ¹³C-NMR spectroscopy, yielding derivatives (A–J). To further investigate the effects of structural modifications on API’s biological activity, an ovalbumin (OVA)-induced asthma model was established in mice to evaluate the antioxidants’ activity. Hematoxylin-eosin staining was used to observe pathological changes in lung tissue, and oxidative stress-related parameters, including ROS, SOD, and MDA, were measured to assess the derivatives’ protective effects against oxidative damage. The results showed that the 10 synthetic derivatives exhibited varying degrees of oxidative stress during treatment. Compared with the model group, the API derivative treatment group significantly reduced ROS and MDA levels and increased SOD activity. Moreover, treatment with the compounds reduced the levels of pro-inflammatory cytokines, including TNF-α, IL-6, and IL-1β, and decreased serum IgE levels. Histopathological examination further demonstrated that the compounds alleviated inflammatory cell infiltration and tissue damage in the lungs. Structure-activity analysis indicated that, among the 10 derivatives, the tri-substituted API derivatives exhibited superior antioxidant activity compared to the di-substituted API derivatives. By modifying the chemical structure of API, its antioxidant activity in OVA-induced bronchial asthma was significantly enhanced. 5,7,4′-O-triethyl API and 5,7,4′-O-triacetyl API demonstrated therapeutic effects comparable to those of dexamethasone and show promise as lead compounds for the development of novel asthma treatments. Full article

This study evaluated the effects of tamarind (Tamarindus indica L.) pulp as a marinade on the physicochemical quality (marinade liquid uptake, water-holding capacity, cooking loss, proximate composition, water activity, pH, color, and texture), oxidative stability (lipid oxidation), microbiological characteristics (mesophilic aerobic counts, Enterobacteriaceae, Gram-positive cocci, and molds and yeasts), and sensory attributes of eye of round beef (M. semitendinosus). Three treatments were compared: non-marinated control (C), brine (B; 2.5% NaCl), and NaCl with tamarind pulp (BPT; 2.5% NaCl + tamarind pulp). Tamarind incorporation significantly reduced pH and water-holding capacity, resulting in lower moisture content and higher ash and carbohydrate levels. BPT samples exhibited increased lightness (L*) and yellowness (b*) and reduced redness (a*), reflecting pigment contribution and acid-induced structural modifications. Texture profile analysis showed lower hardness and chewiness in BPT throughout storage, demonstrating improved tenderness. Lipid oxidation increased in B but remained controlled in BPT, highlighting the antioxidant potential of tamarind pulp. Tamarind selectively improved the microbiological profile by inhibiting Enterobacteriaceae and reducing mesophilic aerobic bacteria, although it was less effective in controlling molds and yeasts. Sensory evaluation showed that B treatment received the highest scores for flavor and overall acceptability, while BPT was characterized by fruity, acidic, and sweet notes, resulting in a distinctive sensory profile without reducing acceptability relative to the control. Overall, tamarind pulp substantially modulated the quality characteristics of marinated eye of round beef, providing advantages in oxidative stability, microbial control, and texture while also reducing water-holding capacity, altering color, increasing mold and yeast growth, and producing a distinctive sensory profile. These findings highlight both the potential and the limitations of tamarind pulp as a natural ingredient for clean-label meat products. Full article

The growing demand for natural aggregates and continued stockpiling of steel slag have increased interest in using steel slag aggregate (SSA) in road engineering. However, delayed hydration of free calcium oxide (f-CaO) and free magnesium oxide (f-MgO), porous and rough surfaces, and the potential release of hazardous elements constrain its long-term application. This review compares aging treatment, surface modification, direct carbonation, microbially induced calcium carbonate precipitation (MICP), and combined treatments from a raw-material heterogeneity and defect-oriented perspective. Their effectiveness is strongly condition-dependent. Aging treatment can control volume expansion, but reaction depth and treatment uniformity remain limited. Surface modification can reduce water absorption and improve interfacial performance but cannot eliminate internal expansive phases. Direct carbonation and MICP can stabilize reactive phases, refine pore structures, and reduce the mobility of some elements, but are limited by mass transfer and equipment requirements, and by mineralization uniformity and ammonium by-product management, respectively. Combined treatments can address multiple defects but increase process complexity, resource consumption, and quality-control requirements. Because material properties and evaluation methods vary among studies, reported performance gains should not be directly used for technology ranking. Instead, technology selection should follow the framework of “raw-material characteristics–dominant defects–preferred technology–engineering boundaries”. From a life-cycle perspective, sustainability depends on balancing resource and environmental benefits against additional treatment burdens. Near-term implementation should integrate raw-material classification, process monitoring, long-term durability and dynamic leaching verification, and the progressive incorporation of key performance and environmental indicators into road-material specifications and engineering acceptance criteria. Full article

In this study, pure ZnO and Ho-doped ZnO powders (1 and 2 mol % Ho) were synthesized via hydrothermal and sol–gel methods and evaluated for their tribocatalytic activity toward the degradation of paracetamol, an emerging pharmaceutical contaminant in aquatic environments. Structural, morphological, and optical properties of the obtained materials were investigated by X-ray diffraction (XRD), scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM/EDS), ultraviolet–visible (UV–Vis) spectroscopy, X-ray photoelectron spectroscopy (XPS), and electron paramagnetic resonance (EPR) spectroscopy. SEM observations revealed pronounced morphology differences between the synthesis routes, with hydrothermally prepared samples exhibiting well-defined rod-like structures. XPS and EPR analyses provided evidence for successful Ho modification of ZnO and the presence of defect-related electronic states associated with Ho doping. The tribocatalytic performance was examined in distilled, tap, and mineral water using friction rods with different geometries in order to assess the influence of synthesis route, Ho concentration, and water composition. Among all the investigated materials, hydrothermally synthesized ZnO doped with 2 mol % Ho exhibited the highest tribocatalytic activity, achieving 96.91% degradation of paracetamol at an initial concentration of 15 mg/L within 24 h. The enhanced performance was attributed to improved charge separation induced by Ho modification, combined with the favorable rod-like morphology of the particles. Higher degradation efficiencies were observed in distilled water compared to tap and mineral water, indicating the important role of dissolved ions during the tribocatalytic process. These findings demonstrate that the synthesis route, Ho doping, and water composition collectively govern the tribocatalytic performance of ZnO-based materials, highlighting their potential for water purification. Full article

Ultrasound technology has emerged as a promising non-thermal approach for modifying the structural and functional properties of food matrices. However, its impact on starch digestibility remains insufficiently understood, particularly in complex systems such as cereal, legume, and pseudocereal flours. This study evaluated the effect of power ultrasound on the functional properties and in vitro digestibility of durum wheat (DWF), chickpea (CF), and amaranth (AF) flours. Flours were treated using an ultrasonic probe (20 kHz, 60% amplitude) for 10 and 20 min while maintaining the sample temperature at 15 °C. Structural and functional properties were assessed, including color, morphology, water absorption, FT-IR spectra, pasting behavior, thermal properties, and starch fractions. Ultrasound induced structural modifications, including starch granule disruption and increased surface roughness. Lightness increased in DWF, CF, and AF, although the magnitude of the response differed among flour types. Water absorption improved in DWF but decreased in CF and AF. FT-IR spectra suggested molecular rearrangements, while viscoelastic and thermal analyses showed increased viscosity in DWF and CF and reduced viscosity in AF. Ultrasound also modified starch fractions and in vitro starch digestibility in a flour-dependent manner, reflecting the distinct structural responses of cereal, legume, and pseudocereal starches to acoustic cavitation. Overall, ultrasound modified the functionality of flour and starch digestibility in a matrix-dependent manner, supporting its potential as a clean-label technology for tailoring the functional properties of different flour matrices. Full article

Glow-discharge plasma (GDP) poling is revisited as an electrode-free method for activating piezoelectricity in poly(vinylidene fluoride) (PVDF) films. Although this method was proposed several decades ago, its effect on the properties of PVDF films has remained poorly understood. In this work, we demonstrate that GDP enables efficient poling of oriented PVDF films without pre-deposited electrodes and investigate the relationship between plasma treatment time, structural evolution, and piezoelectric response. Commercially available 25 μm-thick oriented PVDF films (PolyK) were treated in a DC glow discharge for 15 s to 15 min and characterized using FTIR, DSC, piezoresponse force microscopy, UV–Vis–NIR spectrophotometry, quasi-static d₃₃ measurements and water contact-angle measurements. GDP poling produced a side-averaged piezoelectric coefficient d₃₃ of up to ~25 pC/N within 1–5 min, with local maxima at approximately 1, 2.5, and 5 min. This behavior was accompanied by pronounced changes in the domain structure, including an increase in the ferroelectric domain size from 86 to 552 nm, while the crystallinity and electroactive phase fraction changed only moderately. Plasma treatment also increased the wettability of the plasma-facing surface, reducing the water contact angle from about 85° to 42° within 3 min. At longer treatment times (>5 min), however, the piezoelectric response decreased and the optical transparency deteriorated because of increased haze and turbidity, most likely associated with plasma-induced chemical modification of the surface layers. These results indicate that GDP poling has an effective processing window of 1–5 min. The proposed approach provides a vacuum-compatible and electrode-free route for preparing PVDF films with increased surface wettability for flexible piezoelectric sensors, wearable electronics, and integrated polymer-based devices, because it is compatible with electrode deposition on an already activated polymer surface within a single vacuum cycle. Full article