Search Results (10,591)

Rapid, low-cost ethanol quantification is vital for beverage quality control, biofuel production, and pharmaceutical applications, yet current approaches are costly, reagent- or label-dependent, or rely on spectroscopy with substantial sample preparation. We introduce a purely cell-based, label-free biosensor that exploits temperature-gradient-induced spontaneous detachment of Saccharomyces cerevisiae from a chip surface. The readout is the detachment half-time, t_d50, derived from time-resolved changes in interfacial thermal resistance, R_th, at the solid–liquid interface. Cells were pre-exposed to ethanol (0–70% v/v) and the detachment kinetics monitored using the heat transfer method (HTM). Under these conditions, cells display a pronounced non-monotonic t_d50 response with a peak around 20% v/v ethanol. Overall, the t_d50 rises from ~45 min (0% ethanol) to ≳10 h (20%) and then decreases, with no detachment at 60% and beyond. Critically, cell quality gates the detachment window. Fresh yeast responds up to ~50%, whereas aged yeast ceases to detach above ~8%, demonstrating a dual-function assay. Complementary measurements show that ethanol decreases surface tension monotonically, as expected, while optical/SEM imaging reveals aggregation above the detachment window. Requiring only a heater and a temperature probe, this platform offers a compact and low-cost strategy for ethanol sensing. Its applicability in a complex matrix is further demonstrated using whiskey diluted to selected alcohol concentrations, which produced responses consistent with the ethanol calibration trend. Potentially, it also offers a thermal assay for real-time monitoring of microbial cell quality across biotechnology and bioengineering applications. Considering ethanol as a proxy for drugs, the strategy may also support label-free drug screening on cells. At a fundamental level, the non-monotonic effect of ethanol, and especially the sharp maximum at 20%, remains unresolved and invites further studies. Full article

This study investigates the mechanical properties and corrosion behavior of a Co-free Fe₄₀Ni₃₀Cr₂₀V₈Mo₂ (at.%) multi-principal elements alloy (MPEA) designed for potential applications in aggressive environments. The alloy exhibits a balanced combination of strength and ductility, with a yield strength of approximately 258 MPa, an ultimate tensile strength of about 647 MPa, and a fracture elongation of around 52%, of which deformation is primarily governed by dislocation-mediated plasticity. In terms of corrosion performance, the alloy demonstrates excellent resistance in chloride-containing environments. Potentiodynamic polarization tests reveal a wide and stable passive region of approximately 1.28 V_SCE and a high pitting potential of about 0.975 V_SCE, indicating exceptional stability of the passive film. Electrochemical impedance spectroscopy (EIS) further confirms the high impedance and protective nature of the surface layer. X-ray photoelectron spectroscopy (XPS) analysis reveals that the superior anti-corrosion property is attributed to the formation of a passive film enriched with protective Cr₂O₃ and V, Mo oxides, which collectively construct an effective barrier against chloride-induced attack by reducing donor density. This work provides valuable insights for the development of alternative alloys to replace Co-containing systems in demanding corrosive applications. Full article

Lead (Pb²⁺) and cadmium (Cd²⁺) are among the most hazardous heavy metal pollutants in wastewater owing to their high toxicity, environmental persistence, and detrimental impacts on human health and aquatic ecosystems. In this study, a novel ternary magnetic composite, SnFe₂O₄/activated carbon/polypyrrole (SnFe₂O₄/AC/PPy), was effectively synthesized and tested as an effective adsorbent in the removal of Pb²⁺ and Cd²⁺ from aqueous water. The composite was prepared by depositing spinel SnFe₂O₄ nanoparticles on activated carbon, followed by in situ polymerization of polypyrrole to enhance surface functionality and adsorption affinity. The successful fabrication of the porous SnFe₂O₄/AC/PPy hybrid composite was confirmed through FTIR, XRD, SEM–EDS, BET, XPS, and VSM characterization. The composite demonstrated a relatively high surface area (352.3 m²/g) and adequate magnetic responsiveness (12.33 emu/g), ensuring facile magnetic separation following wastewater treatment. Batch adsorption experiments showed great removal efficiency of 95.02 and 92.48% for Pb²⁺ and Cd²⁺ ions, respectively, at optimum conditions. The adsorption equilibrium data followed the Langmuir isotherm model with maximum adsorption capacities of 187.07 mg/g for Pb²⁺ and 96.45 mg/g for Cd²⁺ ions, which were attributed to monolayer adsorption on homogenous active sites. The kinetic and isothermal model indicated that the adsorption process was controlled by the combination of physical and chemical interactions. Thermodynamic parameters showed negative Gibbs free energy and enthalpy changes (ΔH° = −49.74 kJ/mol for Pb²⁺ and −38.82 kJ/mol for Cd²⁺ ions), confirming the spontaneous and exothermic nature of adsorption. Furthermore, the increasingly negative ΔG° values at lower temperatures indicated that the adsorption was thermodynamically more favorable under cooler conditions. According to the regeneration studies, the composite maintained a high removal efficiency after five consecutive cycles. In general, SnFe₂O₄/AC/PPy composite has good potential as a stable, reusable, and high-performance adsorbent to treat heavy metal wastewater. Full article

Ash-free net heat content (AF-NHC) represents the combustible heat content of plant biomass and is an important parameter in fire behavior and fire effects modeling. Despite its widespread use, little information exists regarding seasonal and regional variation in AF-NHC among common woody fuels of the southeastern US. This study quantified seasonal and regional variation in AF-NHC among five common woody species in eastern Texas: yaupon (Ilex vomitoria), greenbrier (Smilax spp.), eastern red cedar (Juniperus virginiana), Chinese privet (Ligustrum sinense), and escarpment live oak (Quercus fusiformis). Foliage samples were collected during the dormant and growing seasons across the Pineywoods, Post Oak Savannah, and Blackland Prairie ecoregions and were analyzed using oxygen bomb calorimetry. Linear mixed-effects models evaluated species, season, and species × season effects while accounting for regional variation. AF-NHC ranged from 17.35 to 19.92 MJ kg⁻¹ and differed significantly among species and seasons, with distinct species-specific seasonal trajectories (p < 0.05). Regional variation accounted for approximately 41% of total model variance, indicating that environmental conditions influence fuel thermal properties. AF-NHC was greatest in yaupon and red cedar, intermediate in privet and greenbrier, and lowest in live oak. Although AF-NHC likely exerts less influence on fire behavior than fuel consumption and the rate of spread, species-specific differences in combustible heat content may contribute to variation in potential heat release and fuel combustibility. These findings provide baseline AF-NHC values for common eastern Texas woody fuels and improve the understanding of spatial and temporal variation in fuel thermal properties relevant to fire effects and wildfire hazard assessment. Full article

Hands-free command interfaces are essential for users who cannot reliably operate joysticks or upper-limb myoelectric control. Neck–shoulder surface electromyography (sEMG) is a promising alternative; however, performance is often reported using window-level validation which can overestimate accuracy due to overlap and trial leakage, and false-trigger behavior is not always quantified when an idle REST state is included. This pilot study presents a motion-capture (MoCap)-referenced decoding framework that uses four bilateral upper trapezius (UT) and sternocleidomastoid (SCM) sEMG channels with integrated inertial measurement units (IMUs). Optical MoCap was used as an external kinematic reference to support baseline-posture assessment and movement-execution quality control. Seven commands were decoded (shrug L/R, double shrug, rotation L/R, rotation + shrug L/R). To enable an eight-class formulation, a REST class was defined using low-activity segments extracted from baseline recordings and included in the evaluation. Computationally efficient time-domain sEMG features, pattern/symmetry descriptors, and baseline-referenced IMU kinematics (including an SCM yaw-range indicator) were classified using linear discriminant analysis (LDA), k-nearest neighbors (kNN), and linear support vector machine (SVM), evaluated using within-subject testing, trial-wise grouped cross-validation, and leave-one-subject-out (LOSO) testing. Across six participants, within-subject mean best-per-subject accuracy was 96.02% (seven-class) and 96.35% (eight-class); and pooled trial-wise accuracy reached 92.1% and 90.5%, respectively. Under LOSO, best-configuration accuracy decreased to 60.4% and 63.8% for the seven-class and eight-class formulations, respectively. Across the top LOSO configurations, REST FAR ranged from approximately 9.8% to 25.6%. These findings demonstrate controlled offline pilot feasibility and quantify key generalization and REST false-activation trade-offs, providing a foundation for future validation in larger, more diverse, and clinically relevant populations. Full article

A methodology for deriving high-resolution (5-km) surface shortwave radiative (SWR) fluxes over the Arctic was applied to observations acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS) during the spring and summer melt season (March–September) of 2007, when the Arctic experienced a historically significant and well-documented decline in sea ice extent. The derived SWR fluxes were used to estimate solar heat input into the Arctic Ocean during the melt season, a task that had not previously been undertaken at such high spatial resolution. According to the National Snow and Ice Data Center (NSIDC), Arctic sea ice extent reached a record minimum of 4.13 million km² on 16 September 2007, approximately 38% below the 1979–2000 climatological mean and 24% below the previous record minimum in 2005. This extreme reduction in sea ice resulted in several weeks of ice-free opening along portions of the ‘Northwest Passage’. Availability of high spatial resolution SWR fluxes in the Arctic is particularly important for improving estimates of solar heat input into the Arctic Ocean, especially within the highly heterogeneous marginal ice zone. To facilitate comparison with sea ice concentration products from NSIDC, the MODIS-derived 5-km SWR fluxes were aggregated to 0.25° equal-area grid cells (approximately 25 km resolution). Our results show that the abrupt increase in the open water fraction produced anomalies in solar heating to the upper ocean exceeding 300%, hereby enhancing the ice–albedo feedback mechanism and promoting further sea ice melt. The estimated monthly cumulative solar heat input to the ocean for a nominal 1° grid cell was 164.9 MJ m⁻² in May. In contrast, the corresponding four 0.25° sub-grid cells, resolved using the high-resolution MODIS data, exhibited cumulative heat inputs of 58.0, 93.0, 189.3, and 296.4 MJ m⁻², respectively. Although the average heat input for the 1° grid cell (165 MJ m⁻² was similar to the average value obtained from the four 0.25° grid cells (159 MJ m⁻² the substantial sub-grid variability is important because the oceanic and sea-ice responses to solar heating are highly nonlinear. Consequently, unresolved spatial variability can significantly affect the magnitude of derived quantities and associated feedback processes. These findings demonstrate the importance of high-spatial-resolution radiative flux information for accurately quantifying ocean heating and ice–ocean interactions in the Arctic. Full article

This paper presents a three-dimensional generalization of the M-integral, formulated as an interaction integral based on a bilinear strain energy density, for the mixed-mode decoupling of crack front energies in finite structural components. The proposed $M_{\theta }^{3D}$ integral combines real and virtual mechanical fields within a local spherical reference frame, enabling the separate evaluation of mode I (opening), mode II (in-plane shear) and mode III (out-of-plane shear) energy release rates along arbitrary crack front lines. The theoretical framework, derived from Noether’s theorem and the virtual work principle, is implemented in the Cast3M finite element code using a toroidal integration domain with a local theta weighting function. Numerical validations are conducted on the Mixed-Mode Crack Growth (MMCG) specimen, a geometry representative of structural components subjected to combined tension and shear. Three key findings are demonstrated: (i) practical domain independence is achieved for all three fracture modes; (ii) the three-dimensional approach converges to the plane-stress solution for thin specimens and reveals significant deviations from plane-strain assumptions; (iii) even under nominally mode I + II loading, a non-negligible mode III component emerges due to Poisson-induced out-of-plane effects, with magnitude increasing at free surfaces and for thicker geometries. These results indicate that finite-thickness and out-of-plane effects can significantly affect the partition of fracture energy between modes. For the MMCG configuration investigated here, the three-dimensional formulation shows the limitations of two-dimensional assumptions and provides an energetic basis for the analysis of mixed-mode fracture in finite-thickness components. Full article

Gold is considered the most widely used surface for the development of aptamer-based layers. However, its high cost, laborious surface-cleaning protocols, and susceptibility of receptor layers to degradation in complex samples, including biological fluids, enforce the search for alternative transducers. One solution is the application of carbon materials, which are inexpensive and allow for the use of a wide potential range when electrochemical measurements are performed. Herein, we present studies on the elaboration of aptamer receptor layers formed on carbon macroelectrodes. To achieve this, a one-step procedure for aptamer molecules containing a pyrene or anthracene group at the 5′ end was used, with immobilization via adsorption facilitated by Π–Π interactions between the anchor group and the carbon surface. It was evidenced that using anthracene-modified aptamer and sodium anthraquinone-2-sulfonic acid (AQMS) redox indicator enabled the detection of a model analyte–vancomycin below the millimolar concentration range. It was also revealed that vancomycin can be successfully detected in serum samples, and the aptasensor exhibits good selectivity towards vancomycin. The latter was observed by comparison of responses in PBS containing solely vancomycin and a solution spiked with vancomycin and a mixture of antibiotics. Full article

The present study investigated the effect of liquid smoke (LS) on the physicochemical, structural, barrier, and functional properties of okra mucilage–corn starch (OMCS) films. Formulations containing varying concentrations of LS (0–3%) were prepared using the casting method. The incorporation of LS modified the rheological behavior of the film-forming dispersions, as evidenced by increased apparent viscosity and consistency index. In the films, water solubility increased from 43.6 to 53.2%, contact angle increased from 31.9° to 55.6°, and opacity increased from 4.73 to 8.83, while water vapor permeability decreased from 1.05 to 0.88 g·mm·m⁻²·h⁻¹·kPa⁻¹, indicating modifications in matrix organization and surface hydrophobicity. Tensile strength increased from 26.3 to 40.5 MPa at 3% LS, accompanied by a slight reduction in elongation, suggesting enhanced structural rigidity. Structural analyses revealed interactions between the LS phenolic compounds and the polysaccharide hydroxyl groups, resulting in a more cohesive polymeric network. LS was the main contributor to the film’s antioxidant activity owing to its elevated phenolic content and free radical scavenging capacity. The films also showed substantial degradation under soil burial conditions, with mass loss ranging from 61% to 96%. Overall, LS proved to be an effective functional additive, improving the structural and antioxidant performance of OMCS films and expanding their potential for active food packaging applications. Full article

Changes in wood moisture content significantly affect its dimensions, mechanical properties, and vibrational characteristics. Thermal treatment is one of the most convenient approaches for improving the moisture resistance of wood; however, the effects of treatment conditions on moisture content and vibrational characteristics after short-term cyclic moisture absorption have not been clearly investigated. In this study, dry thermal treatment at 160–220 °C for three different durations was applied to Japanese cedar specimens. Higher thermal treatment temperatures and longer treatment times decreased the equilibrium moisture content (EMC). The fundamental resonant frequency of the free–free flexural vibration (f₁) increased with increasing treatment temperature, whereas it decreased over a longer duration. All specimens were subjected to three cycles of moisture change tests from 60%RH to 98%RH at 40 °C to track the change in moisture content, f₁ and its loss tangent (tanδ). The specimens treated at higher temperatures maintained a lower moisture content and higher f₁. Under most treatment conditions, the moisture content at 98%RH increased from the first to the second cycle and remained constant in the third cycle. On the other hand, the resonant frequency at 98%RH remained unchanged from the first to the second cycle but increased in the third cycle. This indicates that the moisture surface became saturated in the second cycle, and moisture diffusion from the surface to the inside of the specimen increased with the number of cycles. Near-infrared absorption revealed that high-temperature treatment caused thermal decomposition of hemicellulose and an increase in apparent crystallinity due to a reduction in the amorphous region of cellulose. These changes enhance the hydrophobicity of the cell wall, contributing to moisture resistance and vibrational stability. Full article

Background/Objectives: The aim of current study was the significant improvement of both the flowability and the compressibility of mesoporous silica microparticles (MSMs), to enable the formulation a potential drug delivery system. MSMs are of emerging interest in the pharmaceutical industry, due to their numerous advantages and versatile applicability, such as improvement in aqueous solubility and epithelial permeability, thus enhancing the oral bioavailability of drugs. However, the formulation of these types of materials has been a major challenge. This problem originates from poor powder flow characteristics due to particle properties. Methods: A binder-free high-shear wet granulation (HSWG) process was performed to improve the flowability and compressibility of the model material, meanwhile preserving its porosity. The prepared granules were characterized by particle size, size distribution, yield percentage, particle morphology, porosity, powder flowability, crushing strength, and stability. Micro-CT measurements were performed to examine the structure of the granules and to see the internal segmentation resulted by the two-step granulation process. The granules were compressed into tablets to evaluate the compressibility behavior based on the models of Kawakita and Walker. The physical parameters of the compressed tablets, such as breaking hardness, tensile strength, and thickness, were tested. Results: The prepared granules were evaluated successfully according to the mentioned properties and found to be satisfactory compared to the raw materials. The binder-free method appeared to be effective, thus the use of binders may be avoided if the process is designed well and critical process parameters (CPPs) selected carefully. The granules showed good stability over a one-year testing period. The micro-CT test also verified the success of the initial concept of preparing core–shell structured granules, and enabled the determination of macropores. Nevertheless, the results were completed with BET measurements to determine specific surface area of the granules. Conclusions: The effect of the critical process parameters of the granulation process on all the mentioned attributes was investigated and since major differences were observed between the batches, the effect of the selected CPPs were also verified. Full article

This study investigated the valorization of agro-industrial by-products, namely Nigella sativa seed meal (BCSM) and whey, as functional ingredients to improve the quality of rice-based gluten-free bread. A Response Surface Methodology (RSM) approach was applied to optimize formulation parameters and evaluate their effects on physicochemical, rheological, nutritional, and sensory properties. The optimized formulations showed distinct performance profiles depending on the rice matrix and ingredient balance. The optimized brown rice bread (OBRB), characterized by the highest BCSM incorporation (10 g), showed the most relevant functional and nutritional improvements, including increased dietary fiber, enhanced antioxidant activity, and reduced hardness and chewiness compared with the corresponding control. In contrast, the optimized red rice bread (ORRB), characterized by low BCSM content and higher whey incorporation, mainly contributed to improved specific volume and crumb structure. Rheological analysis revealed distinct structural behaviors, with BCSM contributing to a more rigid and structured matrix, while whey promoted a softer and more compliant dough system. Sensory evaluation confirmed that the incorporation of these by-products did not negatively affect acceptability, with overall acceptability scores ranging between 5 and 6. Overall, these results indicate that OBRB was the most promising formulation for functional enrichment, whereas ORRB was mainly associated with structural optimization. This study demonstrates that BCSM and whey can be strategically used as formulation-dependent ingredients for developing nutritionally enhanced and structurally improved gluten-free bread, contributing to the sustainable valorization of food industry by-products. Full article

Metal oxide nanomaterials tailored at the nanoscale are opening new avenues for advanced electroanalytical sensing devices with enhanced properties, including improved electrocatalytic activity. In this work, a novel Mn₂Mo₃O₈/MnO-MWCNT nanocomposite was employed to modify a screen-printed carbon electrode, enabling the fabrication of an amperometric sensor for H₂O₂ operating at relatively low applied potential due to the catalytic activity of the nanocomposite. Further functionalization of this nanostructured surface with glucose oxidase allowed the construction of an electrochemical glucose biosensor, where the Mn₂Mo₃O₈/MnO-MWCNT material acted as an efficient electrocatalyst for hydrogen peroxide detection. The H₂O₂ sensor exhibited a linear response from 0.06 mM to 3.00 mM, with a sensitivity of (2.22 ± 0.02) µA mM⁻¹ and a detection limit of 22 µM. The glucose biosensor showed a linear response in the range from 0.10 mM to 18.9 mM glucose, with a sensitivity of (0.345 ± 0.005) µA mM⁻¹, and a detection limit of 29 µM. The biosensor displayed excellent selectivity and high stability and was successfully applied to the determination of glucose in lactose-free skimmed milk. Full article

Fresh broccoli is highly perishable, exhibiting rapid yellowing and quality deterioration with a short shelf life. In this study, we investigated the effects of nanomaterial-modified atmosphere packaging (MAP) bags with different thicknesses, designated as 2.5C (25 μm) and 4C (40 μm), on the physiological and biochemical changes in broccoli were evaluated during storage at 20 ± 1 °C for 8 days. Results showed that both MAP treatments remarkably delayed floret senescence by inhibiting the rapid color transition from green to yellow, as indicated by alterations in L*, a*, b*, and hue angle values, as well as by suppressing chlorophyll degradation. The 2.5C treatment exhibited a more pronounced effect during storage. MAP treatments helped maintain commercial quality by preserving total phenols and vitamin C (Vc) content, retaining stem firmness and surface glossiness, regulating post-opening respiration rate and reducing water loss. MAP treatments also effectively suppressed the accumulation of superoxide anion (O₂•⁻) and hydrogen peroxide (H₂O₂). Furthermore, MAP treatments enhanced free radical scavenging capacity, as demonstrated by DPPH and ABTS assays and the O₂•⁻ scavenging rate in broccoli. These results indicate that MAP treatment with an appropriate thickness (e.g., 2.5C) effectively inhibits excessive ROS production and enhances antioxidant capacity, thereby delaying floret chlorophyll degradation and senescence. This study provides a foundation for developing effective and green preservation strategies using physical MAP treatments for fresh broccoli. Full article

In this study, we report the results of the structural characterization and electrochemical evaluation of novel cobalt-free layered Ruddlesden–Popper (RP) oxides, La₂SrFe₂O_7−δ and La₂SrFe_1.8Ga_0.2O_7−δ, as electrode materials for intermediate-temperature solid oxide cells. X-ray diffraction confirmed the formation of RP phases and phase stability after reducing treatment. The materials showed compatible thermal expansion behavior, with slightly lower thermal expansion coefficients for the Ga-doped composition. Oxygen pressure relaxation measurements demonstrated that the oxygen surface exchange coefficient increases with temperature and pO₂, while Ga substitution slightly reduces the O₂/oxide exchange rate, which may be associated with a lower concentration of oxygen vacancies. The electrical conductivity in air was higher for La₂SrFe₂O_7−δ than for the Ga-doped sample, while both compositions showed much lower conductivity under reducing conditions. Symmetrical cell impedance spectroscopy showed high polarization resistance for the electrodes, which was substantially reduced by applying a Ag current collector (0.43 Ω cm² for La₂SrFe₂O_7−δ and 0.73 Ω cm² for La₂SrFe_1.8Ga_0.2O_7−δ at 800 °C), consistent with the limited electronic conductivity of the oxide layers. Overall, both oxides exhibit structural stability, acceptable thermomechanical compatibility, and measurable oxygen exchange activity, making them promising candidates for further development as cobalt-free electrodes in solid oxide cells. Full article