Search Results (7,364)

In this investigation, the local mode model for C-H overtone transitions in hydrocarbons and the thermal lens (TL) technique are used to obtain vibrational overtone spectra and subsequent analysis of hydrocarbon impurities in liquid solutions. The experimental thermal lens design enables the detection of hydrocarbon solutes in trace amounts within a hydrocarbon solvent by exciting two distinct vibrational overtones. To exemplify the method, we present the thermal lens signal corresponding to the (Δυ = 6) overtone of benzene or naphthalene as impurities in solvents such as n-hexane or iso-octane. The lowest composition recorded for benzene in n-hexane was 0.005%, while for naphthalene in n-hexane it was 0.001%. Additionally, we explore more sensitive experiments where the (Δυ = 5) transition of the impurity is detected concurrently with the (Δυ = 6) transition of the solvent. This analytical method can also be adapted for use with saturated alcohols in solution contaminating hydrocarbon solvents. Full article

Interfacial coupling between CoFe₂O₄ (CFO) nanoparticles and oxidatively functionalized multi-walled carbon nanotubes (MWCNTs) enables controlled modulation of structural, optical, and spin dynamic properties in CFO–MWCNT nanocomposites. The solvothermal synthesis promotes nucleation of CFO on –COOH/–OH functional groups, ensuring uniform anchoring along the nanotube surface. X-ray diffraction confirms a cubic spinel phase with lattice expansion from 8.385 Å to 8.410 Å and crystallite growth from 18 nm to 25 nm, reflecting strain transfer and partial nanoparticle coalescence at the carbon interface. The observed bandgap narrowing from 2.72 eV to 2.50 eV, confirmed via Tauc plot analysis, is attributed to localized defect states induced by charge delocalization and orbital hybridization at the interface of the CFO–MWCNT boundary. DC magnetometry reveals a reduction in saturation magnetization from 46 emu/g to 35 emu/g due to diamagnetic dilution and interfacial spin canting, while coercivity decreases from 852 Oe to 841 Oe, indicating modified pinning and domain-wall dynamics associated with exchange-coupled interfaces. Ferromagnetic resonance measurements show a resonance field shift from 3495 G to 3500 G and an increase in the Landé g-factor from 1.97 to 2.00, signifying altered spin–orbit coupling and enhanced local magnetic perturbations. The spin–lattice relaxation time increases from 1.41 ns to 1.59 ns, demonstrating suppressed phonon-mediated relaxation and improved spin coherence across the hybrid network. Spin density rises from 3.72 × 10²² to 4.58 × 10²² spins/g, confirming an increase in unpaired electrons generated by orbital asymmetry at the interface. The anisotropy field and effective magnetocrystalline anisotropy constant exhibit pronounced modulation, evidencing strengthened exchange stiffness and altered Co²⁺/Fe³⁺ superexchange pathways. These results establish CFO-MWCNT nanocomposites as tuneable platforms for spintronic logic elements, high-frequency microwave attenuation, and magneto-optical device architectures. Full article

Microplastics (MPs) and microcystins (MCs) frequently occur together in eutrophic environments. However, their interaction in aquatic systems is poorly understood. This study aimed to examine how MP particle size and salinity influence the adsorption behaviour of the cyanotoxin MC-LR onto polystyrene MPs (PS-MPs). Two particle size groups (180–500 µm and 700–1000 µm diameter) were mixed with a microcystin-LR (MC-LR) producing Microcystis aeruginosa lysate in either freshwater (salinity ≤ 0.05 g L⁻¹) or brackish water (salinity 16.00 g L⁻¹) and incubated at 25 °C in an orbital shaker for 48 h. MC-LR bound to PS-MPs was extracted and measured using triple quadrupole LC-MS/MS. The MC-LR adsorption rate exhibited a degree of oscillation throughout time, with peak adsorption observed for the smaller-sized PS-MPs at 1.60% in freshwater after 4 h and 4.60% in brackish water after 6 h. For the larger particle size of PS-MPs, peak adsorption occurred after 4 h, reaching 0.1% in freshwater and 1.3% in brackish water. This study provides evidence that PS-MPs have limited potential as vectors of MC-LR in eutrophic freshwater and brackish environments. Full article

Background/objectives: A rise in infections associated with carbapenem-resistant Providencia species (CRPS) has been observed worldwide. This study presents a genomic analysis of CRPS isolates from four hospitals in Croatia and the outpatient setting, in order to determine the extent of the spread of CRPS in Croatia. In the present study, we applied a combination of phenotypic characterization and molecular analysis of resistance traits to determine the mechanisms and the routes of spread of CRPS. Material and methods: The antibiotic susceptibility testing was performed using disk-diffusion and broth dilution methods. The nature of extended-spectrum β-lactamases (ESBLs), carbapenemases, and fluoroquinolone resistance determinants was investigated by polymerase chain reaction (PCR). In order to obtain an insight into the whole resistome, selected isolates were subjected to the Interarray Genotyping Kit CarbaResist and whole genome sequencing (WGS). Results: In total, 30 isolates were collected from four centers, located in different geographic regions of Croatia. There was uniform resistance to piperacillin-tazobactam, cefuroxime, expanded-spectrum cephalosporins (ESCs), imipenem, ertapenem, meropenem, and ciprofloxacin. Immunochromatographic testing and PCR revealed OXA-48 and NDM carbapenemase in 15 isolates, respectively. Phenotypic tests for ESBLs were positive in all OXA-48 and one NDM-positive organism (16 isolates). The isolates were categorized as extensively drug-resistant (XDR). OXA-48-producing isolates were susceptible only to ceftazidime-avibactam, whereas NDM producers were susceptible to cefiderocol and, in the majority of cases, also to amikacin. WGS identified a plethora of genes encoding resistance to aminoglycosides, such as aadA1 and aadA2, (aph(3″)-Ib and aph(6)-Id, sulfonamides sul1 and sul2, trimethoprim dfrA1, dfrA10, and dfrA12, tetracyclines tet(A) and tet(B), and chloramphenicol catA3 and catA5. Conclusions: Providencia spp., in spite of being a rare pathogen, should be included in the surveillance studies across the medical centers in Croatia. Full article

Accurate estimation of aboveground dry matter accumulation and plant nitrogen content in summer maize is essential for optimizing both yield and nitrogen-use efficiency. Exclusive reliance on two-dimensional multispectral imagery results in data saturation and elevated estimation errors. This study proposes an integrated approach utilizing UAV-based multispectral data, SPAD index, and plant height index, employing deep learning algorithms to develop a precise model for inferring aboveground dry matter accumulation and plant nitrogen content. A field experiment incorporating five nitrogen application levels (N0: 0 kg·ha⁻¹; N1: 120 kg·ha⁻¹; N2: 240 kg·ha⁻¹; N3: 300 kg·ha⁻¹; N4: 360 kg·ha⁻¹) and four summer maize varieties was conducted in the Huanghuaihai region. The results demonstrated that the aboveground dry matter accumulation and plant nitrogen content of the four maize varieties consistently followed a critical nitrogen dilution curve (CNDC) pattern (R² ≥ 0.88), yielding a unified CNDC model (Nc = 34.92 ± 0.64DM^{−0.35±0.01}, R₂ = 0.94). The random forest (RF) model demonstrated exceptional precision in predicting aboveground dry matter accumulation (R² = 0.94, RMSE = 1.56 t ha⁻¹) and plant nitrogen content (R² = 0.92, RMSE = 1.98 g/kg). This method exhibits higher accuracy compared to using vegetation index alone for predicting aboveground dry matter (R² = 0.92, RMSE = 1.56) and plant nitrogen concentration (R² = 0.91, RMSE = 2.49). Its performance significantly surpassed that of the support vector machine (SVM) and partial least squares regression (PLSR) models. This study indicates that the incorporation of SPAD_i and plant height index enhances the accuracy of drone multispectral-based random forest inversion models for nitrogen concentration and aboveground dry matter accumulation in summer maize throughout its growth period. Furthermore, when combined with key nitrogen dilution curves, this approach enables non-destructive and precise detection of nitrogen status in summer maize, thereby providing a scientific basis for nitrogen management and yield prediction. Full article

Reconfigurable intelligent surfaces (RISs) represent a paradigm shift in wireless communications, offering unprecedented control over electromagnetic wave propagation for next-generation 6G networks. This paper presents a comprehensive framework for high-precision indoor localization exploiting cooperative multi-RIS deployments. We introduce the adaptive multi-stage hybrid localization (AMSHL) algorithm, a novel approach that strategically combines fingerprinting-based and geometric time-difference-of-arrival (TDoA) methods through condition-aware adaptive fusion. The proposed framework employs a 4-RIS cooperative architecture with strategically positioned panels on room walls, enabling comprehensive spatial coverage and favorable geometric diversity. AMSHL incorporates five key innovations: (1) a hybrid fingerprint database combining received signal strength indicator (RSSI) and TDoA features for enhanced location distinctiveness; (2) a multi-stage cascaded refinement process progressing from coarse fingerprinting initialization through to iterative geometric optimization; (3) an adaptive fusion mechanism that dynamically adjusts algorithm weights based on real-time channel quality assessment including signal-to-noise ratio (SNR) and geometric dilution of precision (GDOP); (4) a robust iteratively reweighted least squares (IRLS) solver with Huber M-estimation for outlier mitigation; and (5) Bayesian regularization incorporating fingerprinting estimates as informative priors. Comprehensive Monte Carlo simulations at 3.5 GHz carrier frequency with 400 MHz bandwidth demonstrate that AMSHL achieves a median localization error of 0.661 m, root-mean-squared error (RMSE) of 1.54 m, and mean-squared error (MSE) of 2.38 m${}^2$, with 87.5% probability of sub-2m accuracy, representing a 4.9× improvement over conventional hybrid fingerprinting in median error and a 7.1× reduction in MSE (from 16.83 m${}^2$ to 2.38 m${}^2$). An optional sigmoid-based fusion variant (AMSHL-S) further improves sub-2m accuracy to 89.4% by eliminating discrete switching artifacts. Furthermore, we provide theoretical analysis including Cramér–Rao lower bound (CRLB) derivation with an empirical MSE comparison to quantify the gap between practical algorithm performance and theoretical bounds (MSE-to-CRLB ratio of approximately $4.0\times {10}^4$), as well as a computational complexity assessment. All reported metrics have been cross-validated for internal consistency across formulas, tables, and textual descriptions; improvement factors and error statistics are verified against primary simulation outputs to ensure reproducibility. The complete simulation framework is made publicly available to facilitate reproducible research in RIS-aided positioning systems. Full article

The rapid expansion of coastal dredging projects has resulted in the accumulation of large volumes of dredged sediments, creating significant environmental and land-use challenges. Conventional disposal methods, such as landfilling and marine dumping, not only waste valuable resources but also pose risks, including heavy metal contamination and excessive salinity. In this study, dredged sediment from the former sedimentation area of Huanghua Port was systematically examined for its potential reuse as greening soil through a three-stage approach: desalination, amendment with additives, and composting. Water-washing experiments were conducted to optimize desalination parameters, with a focus on the effects of solid-to-liquid ratios and washing solution concentrations on electrical conductivity reduction. Biochar, fly ash, and wood vinegar were then applied as amendments to evaluate their impacts on soil properties, including pH, organic matter, electrical conductivity, and cation exchange capacity. In addition, co-composting experiments with dredged sediment and crop straw were designed to investigate composting dynamics and changes in physicochemical characteristics under different mixing ratios. The results showed that two washes with a 0.3% NaCl solution effectively reduced electrical conductivity to acceptable levels. Subsequent amendment and composting treatments markedly enhanced soil fertility and ecological suitability. In particular, the combination of 1000-fold diluted wood vinegar and straw-to-sediment composting at a 1:3 weight ratio enabled the amended sediment to meet the Chinese standards for Planting Soil Green. Overall, this study establishes a scientific basis and practical strategy for the sustainable recycling of dredged sediments, supporting their application in urban greening and ecological restoration. Full article

Indoor environmental quality directly affects public health and quality of life, among which odor pollution is one of the primary drivers of indoor environmental complaints. Traditional research and management approaches, which rely predominantly on mass concentrations of individual chemical compounds, are fundamentally inadequate for addressing the inherent sensory complexity, dynamic evolution, and subjective perception of indoor odors. Through a systematic literature review, this paper for the first time establishes an integrated research framework for indoor odor pollution across the whole-life-cycle management of the built environment, structured around “source–evolution–evaluation–control”. This framework systematically analyzes emission characteristics of building-related pollution sources, revealing the profound impact of indoor dynamic chemical and biological transformation processes on odor properties. Sensory analysis, instrumental measurements, and intelligent sensing approaches are critically compared in terms of their underlying principles and application boundaries. From an engineering perspective, the effectiveness and limitations of source prevention, ventilation dilution, and terminal purification strategies are comprehensively evaluated. The analysis demonstrates that effective indoor odor management must transcend passive and fragmented mitigation practices, and that its future development depends on the deep integration of environmental chemistry, sensory science, materials science, and artificial intelligence. Finally, this review proposes that by constructing regulation systems based on real-time sensing, digital twins, and intelligent decision-making, indoor odor management can fundamentally shift from reactive complaint-driven responses to proactive health-oriented protection. This paradigm transformation provides a systematic theoretical foundation and a technological roadmap for achieving healthy, comfortable, and sustainable building environments. Full article

Obesity is a major global health challenge that substantially affects vitamin D metabolism and status. Numerous studies have consistently demonstrated an inverse relationship between body fat and serum 25-hydroxyvitamin D [25(OH)D] concentrations. Emerging evidence suggests that lower serum 25(OH)D in obesity largely reflects altered distribution and metabolism rather than a uniform state of true functional deficiency. Adipose tissue functions both as a storage compartment and as a metabolically active organ capable of modulating vitamin D handling. Mechanisms include the sequestration of vitamin D in fat, volumetric dilution across a larger body mass, and the local expression of enzymes involved in vitamin D metabolism. As a result, obese individuals typically exhibit a blunted increase in serum 25(OH)D in response to supplementation, consistent with altered pharmacokinetics and increased distribution volume. Weight loss, particularly the reduction in visceral fat, is associated with modest increases in circulating 25(OH)D, further supporting a distribution-based mechanism. Although low 25(OH)D levels in obesity have been linked to insulin resistance, inflammation, and metabolic syndrome, randomized controlled trials have not consistently demonstrated that supplementation improves clinically relevant outcomes in this population. Meta-analyses confirm that the increase in serum 25(OH)D after supplementation is smaller in obese individuals, indicating that higher doses are often required to achieve comparable levels to those in normal-weight subjects. Obesity thus represents a major determinant of vitamin D deficiency, highlighting the need for individualized supplementation strategies alongside weight management. Understanding the mechanistic basis for low 25(OH)D in obesity is essential for distinguishing true deficiency from altered distribution, informing clinical decisions, and optimizing interventions to maintain adequate vitamin D status and support metabolic health. Full article

Wastewater from food processing industries contains synthetic dyes and preservatives that may pose phytotoxic and genotoxic risks. The present work represents an exploratory study based on a wastewater source and sampling period. Wastewater was characterized by physicochemical analysis and high-performance liquid chromatography (HPLC). Onion seeds and bulbs were exposed to 0% (control), 20%, 40%, 60%, 80%, and 100% wastewater dilution. DNA was extracted from root cells using the cetyltrimethylammonium bromide (CTAB) method. The DNA damage was analyzed by the comet assay. HPLC analysis confirmed the presence of sorbic acid, citric acid, benzoic acid, butylated hydroxyanisole (BHA), and butylated Hydroxytoluene (BHT) by showing corresponding peaks. The mean root length in wastewater was significantly reduced by 55%, 50%, and 65% on days 3, 5, and 7, respectively, relative to the control. On day 3, the highest genotoxicity at 100% wastewater was indicated by 96.69% tail DNA, a tail moment of 108.3 a.u., an Olive tail moment of 58.01 a.u., and a comet length of 136 µm. Enhanced DNA damage persisted on days 5 and 7, with comet lengths reaching 127–149 µm and 111–182 µm, respectively. Although the observed effects may reflect general cytotoxicity arising from a complex wastewater mixture and showed that untreated food processing wastewater presents a significant genotoxic risk and requires effective treatment prior to reuse. Full article

The microbiological safety of whole wheat flour remains a critical issue due to its susceptibility to contamination by spore-forming thermophilic bacteria. In this study, two thermophilic species, Bacillus subtilis and Bacillus mesentericus, were isolated from locally produced wheat grains and used as target microorganisms to evaluate the antibacterial potential of freshly pressed cabbage juices. Juices obtained from five cabbage varieties—red cabbage, white cabbage, napa (Chinese) cabbage, broccoli, and cauliflower—were comparatively assessed using the broth dilution method to determine their minimum inhibitory and bactericidal effects (n = 3). The results revealed pronounced differences in antibacterial efficacy among the tested samples. White cabbage juice exhibited selective inhibitory activity against B. subtilis at a dilution of 1:4, whereas napa cabbage and broccoli juices demonstrated the highest antibacterial activity against both Bacillus species at a dilution of 1:3. Importantly, napa cabbage juice showed no inhibitory effect on Saccharomyces cerevisiae, indicating its compatibility with dough fermentation processes. Spectroscopic analysis of the bioactive fraction obtained from napa cabbage juice revealed characteristic absorption bands at 3422 cm⁻¹ (O–H stretching), 2907–2840 cm⁻¹ (aliphatic C–H stretching), 1740 cm⁻¹ (ester carbonyl group), and 1641 cm⁻¹ (C=C stretching). The predominance of lipophilic compounds, including fatty acid esters, terpenes, and sulfur-containing compounds (734 cm⁻¹), suggests a molecular basis for the observed antibacterial activity against Bacillus spp. Overall, these findings identify napa cabbage as a promising source of selective natural antimicrobial agents capable of enhancing the microbiological safety of whole wheat flour-based bakery products without compromising yeast activity. Full article

High-entropy alloys (HEAs) represent one of the most promising emerging material families, particularly for advanced surface engineering applications. In this work, a near-high-entropy alloy (near-HEA) coating was produced on a 316L stainless steel substrate using laser metal deposition (LMD) from a powder mixture of Inconel 625, Cr and Mo, without the intentional addition of Fe. Due to dilution from the substrate, the resulting alloy contained elevated Fe content while maintaining Cr, Ni and Mo concentrations within the generally accepted compositional range of HEAs. The deposited layer exhibited a dual-phase microstructure consisting of a face-centered cubic (FCC) phase and a highly distorted tetragonal phase forming a periodic network with a characteristic length scale of several hundred nanometers. The hardness of the coating increased to approximately three times that of the substrate, reaching values of 600–700 HV. To further modify the surface properties, laser-induced periodic surface structures (LIPSS) were generated on the polished coating using femtosecond pulsed laser irradiation at different energy densities. The morphology and subsurface structure of the resulting periodic patterns were investigated by scanning electron microscopy. LIPSS with characteristic dimensions ranging from the micrometer to nanometer scale were successfully produced. Cross-sectional analyses revealed that the underlying dual-phase microstructure remained continuous within the laser-structured regions, indicating that LIPSS formation occurred predominantly via metallic ablation without significant phase transformation or amorphization. These results demonstrate the combined applicability of LMD and femtosecond laser structuring for producing mechanically enhanced, micro- and nanostructured near-HEA coatings with potential for advanced surface-related functionalities. Full article

Vanadium–titanium magnetite is a strategically important resource for iron, vanadium, and titanium production, yet its utilization in conventional blast furnace–basic oxygen furnace routes is limited by the dilution of titanium into low-value slag. This study investigates an integrated process route combining pellet preparation, hydrogen-based shaft furnace reduction conducted in the temperature range of 800–1000 °C, and subsequent electric furnace smelting for efficient recovery of Fe, V, and Ti. Pellets prepared from 100 wt.% vanadium–titanium magnetite exhibited sufficient mechanical strength but showed poor reducibility and severe low-temperature reduction disintegration, rendering them unsuitable for hydrogen-based shaft furnace operation. To overcome these limitations, systematic ore blending was applied. An optimized pellet composition comprising 40 wt.% vanadium–titanium magnetite, 50 wt.% high-grade iron ore, and 10 wt.% titanium concentrate achieved reduction degrees above 90%, acceptable swelling and bonding behavior, and low reduction disintegration indices meeting industrial HYL requirements. Industrial trials in a hydrogen-based shaft furnace demonstrated stable operation and consistent product quality, producing direct reduced iron with controlled metallization and enrichment of titanium and vanadium. Subsequent electric furnace smelting achieved clear slag–metal separation, yielding hot metal with high iron and vanadium recovery and a TiO₂-rich slag containing approximately 45 wt.% TiO₂. Recovery rates of Fe, V, and Ti exceeded 90%, confirming the technical feasibility of the proposed process route. Full article

This study investigated the properties of red algae (RA) biocomposite films reinforced with natural sisal fibers and plasticized with glycerol. The polymer was extracted from locally sourced red seaweed and combined sisal fibers at varying fiber loadings (0–45 wt%) using the doctor blading technique. Composite films were analyzed using a variety of methods to evaluate the chemical composition, thermal behavior and mechanical performance. Infrared spectroscopy confirmed the presence of kappa-carrageenan as the dominant polysaccharide in the RA matrix, whereas elemental analysis verified the dilution of sulfur content and enrichment of carbon with increasing fiber incorporation. Thermal stability increased with fiber loading, peaking at 30 wt% sisal fiber before decreasing slightly at 45 wt% due to poor fiber dispersion. Mechanical testing demonstrated an optimal balance between strength and flexibility at 30 wt% sisal fiber, with a 37% increase in strength compared to the pure RA film. Overall, the findings demonstrate that sisal fiber reinforcement enhances the structural integrity and stability of RA-based films, supporting their potential as biodegradable alternatives to petroleum-based plastics. Full article

Ophidiomyces ophidiicola, the agent of ophidiomycosis, has recently been reported in wild snakes in Italy, but the status of captive populations remains unknown. We carried out an opportunistic survey of pet snakes from private collections and, in parallel, performed an exploratory evaluation of a droplet digital PCR (ddPCR) assay adapted from an established probe-based real-time PCR. Non-invasive skin swabs were collected by 32 private owners from 97 snakes, representing 31 species across ten Italian regions. All swabs tested negative for O. ophidiicola by both methods, including samples from four snakes that showed cutaneous lesions at the time of sampling. Both assays yielded consistent amplification up to the 1:1000 dilution (ddPCR 0.38 to 0.94 copies/µL for the culture-derived control and 0.24 to 0.33 copies/µL for the field-derived control at 1:1000), while ddPCR retained positive partitions in some replicates at higher dilutions (up to 1:8000). These results provide preliminary screening data for O. ophidiicola in an opportunistic sample of Italian pet snakes and suggest potential applicability of ddPCR as a complementary tool for low-template diagnostics, while highlighting the need for larger, standardised surveys and formal assay validation. Full article