Search Results (2,074)

Graphene oxide (GO) was prepared by a waterless synthesis route to generate GO sheets, which were then applied to coat calcined oyster shell with fertilizer (OSF) pellets, resulting in the creation of an OSF-GO particle. The GO sheets (ID/IG = 0.86) were characterized by Raman spectroscopy, which showed that the GO-coated OSF pellet features a compact coating approximately 13.68 μm thick. SEM and AFM analyses revealed that the GO sheets displayed a monolayer configuration with a crinkled topography (about 0.91 nm). The EDS analysis confirmed that the core was primarily composed of Ca, K, P, O, N, and C elements. The hydroponic experiment results showed that a GO concentration of 80 mg/L significantly enhanced plant height, stem thickness, and root length in loose-leaf lettuce, while higher concentrations induced oxidative stress. In pot experiments, the OSF-GO composite effectively raised the soil pH from 5.38 to 6.41 and improved nutrient availability. OSF-GO composite functions effectively as both a soil conditioner and slow-release fertilizer (SRF), simultaneously remediating degraded soils and optimizing nutrient delivery. Full article

Background/Objectives: We compared the efficacy of audiovisual sexual stimulation (AVSS) using 3D virtual glasses with a desktop monitor. Methods: In this randomized crossover study, 60 patients with ED underwent two penile duplex Doppler ultrasound sessions 1 week apart, each after intracavernosal prostaglandin E1 injection. Patients were randomly assigned to receive AVSS via 3D virtual glasses or a desktop monitor in the first session, with crossover in the second. We measured the resistive index (RI), erectile hardness score (EHS), peak systolic velocity (PSV), anxiety (State-Trait Anxiety Inventory), and satisfaction (visual analog scale). Results: 3D virtual glasses were associated with superior outcomes. The linear mixed models analysis showed higher adjusted mean RI (p < 0.001), PSV (p < 0.001), and satisfaction (p < 0.001) for 3D glasses. Generalized estimating equations analysis showed patients were 6.68 times more likely to achieve functional erection (EHS ≥ 3) with 3D glasses (odds ratio 6.68, 95% confidence interval [2.54, 17.55], p < 0.001). Anticipatory anxiety before subsequent examinations was lower with virtual glasses (p < 0.001). Conclusions: AVSS with 3D virtual glasses is associated with superior hemodynamic parameters and clinical responses consistent with reduced false-positive diagnoses. It also lowers anticipatory anxiety for subsequent procedures, enhancing patient experience. Full article

The present work investigated the effect of different storage temperatures (10 °C, 30 °C, and 50 °C) on the mechanical, structural, chemical, and microstructural properties of a set of sustainable mortars with gray waste. Three types of mortar were investigated: (1) Type A, prepared from a proportion of 1 part cement: 1 part hydrated lime: 6 parts sand; (2) Type B, prepared from a proportion of 1 part cement: 1 part hydrated lime: 6 parts sand: 0.1 part waste; and (3) Type C, prepared from a proportion of 0.9 part cement: 1 part hydrated lime: 6 parts sand: 0.1 part waste. The waste incorporation reduced compressive strength by 8%, while partial cement replacement reduced by 33%. The cement storage at 10 °C preserved the compressive strength, whereas storage at 50 °C increased it by 8.8%. In type B mortar, the waste incorporation improved compressive strength by 19% at 50 °C. The most substantial enhancement occurred in type C mortar, where cement replacement with residue and storage at 50 °C led to a 27% increase. These results highlight the potential of higher storage temperatures to mitigate cement degradation in humid environments. Furthermore, XRD analysis revealed that cement storage temperature did not affect the formation of primary cement phases, as degradation products were chemically similar to hydration products. However, sustainable mortars exhibited changes in the C-S-H phase signal when the cement is stored for 90 days at 30 °C. Finally, SEM and EDS analyses identified variations in Ca, Si, and O proportions depending on storage conditions. Full article

Clay/natural rubber (Clay–NR) nanocomposites are a sustainable material class with a wide range of applications. The type and amount of the filler added to the rubber matrix promote significant changes in the matrix properties. Montmorillonitic clays (MMT) are mineral, natural fillers. This study investigates the effect of a modified Brazilian polycationic MMT on the nanocomposite rheology and mechanical properties. The MMT was incorporated into a NR matrix in its natural state, and after modification by cation exchange (MMT^Na) and organophilization (MMT^ORG), at concentrations of 2.5 and 5 phr (parts per hundred parts of rubber). The natural and modified clays were characterized by XRD, FTIR, BET, and SEM/EDS. Mechanical tests (tensile strength, elongation at break, and modulus at 100%) indicated that the use of MMT^Na led to increased strength and modulus, whereas a minor decrease in the elongation was observed. However, the use of MMT^ORG yielded the most significant improvements in the mechanical properties. The rheology tests indicated that the Payne effect was not observed, and the strain-dependent behavior arises from matrix-dominated mechanisms, rather than disruption of a filler network. Vulcanization curves showed that the NR-MMT^ORG composites exhibited higher torque values, corroborated by higher crosslink densities. These findings highlight the critical role of cation exchange modification in optimizing MMT dispersion and interfacial interactions within NR matrices, providing design principles for high-performance sustainable nanocomposites. Full article

Israeli higher education institutes are challenged by the growing number of ultra-orthodox students. This requires coping with novel aspects unfamiliar to participants, as students and as teachers in the education system, utilizing online learning as a lever for empowering this marginalized population. The aim of the proposed research was to explore perceptions of ultra-orthodox students studying in B.Ed. programs within a secular college of education towards online courses. Data included transcriptions from 68 narratives of interviews, which were analyzed using a mixed-methods approach, which helped us achieve an in-depth understanding of the difficulties and challenges of these higher education students. Altogether, five themes were identified, namely: technical challenges, ethical/religious challenges, academic challenges, engagement challenges, and aspects of availability. Statements referring to academic challenges and engagement challenges were the most frequent. The number of positive and negative statements was balanced. Also, distinct patterns of responses were identified for married vs. single ultra-orthodox women. Findings demonstrate the complexity of utilizing online learning among ultra-orthodox B.Ed. students, in a twofold manner: personally and community-wise. The study may shed light on online learning in additional marginal communities worldwide that are traditional in nature, and that may benefit from online courses. Full article

Geological Carbon Sequestration (GCS) plays a crucial role in addressing climate change, particularly in oil and gas development. Understanding the reaction of supercritical CO₂ under in situ conditions and its effects on minerals is essential for advancing GCS technology. This study investigates the reaction mechanisms of feldspar (potassium and sodium feldspar) and clay minerals (chlorite, illite, montmorillonite, kaolinite) in CO₂ environments. The impacts on mineral crystal structures, morphologies, and elemental compositions were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and ion concentration measurements (ICP-OES and ICP-MS). The results show that feldspar minerals exhibit lower reaction rates, with sodium feldspar dissolving faster than potassium feldspar, due to the higher solubility of sodium ions in acidic conditions. Chlorite showed significant crystal structure damage after 30 days, while montmorillonite underwent both dissolution and precipitation, influenced by interlayer cation dissociation. Kaolinite exhibited minimal reaction, primarily showing localized dissolution. Additionally, the formation of siderite (FeCO₃) was observed as Fe²⁺ substituted for Ca²⁺ in CaCO₃, highlighting the role of iron-bearing carbonates in CO₂ interactions. The study provides insights into the factors influencing mineral reactivity, including mineral structure, ion exchange capacity, and solubility, and suggests that chlorite, montmorillonite, and illite are more reactive under reservoir conditions, while kaolinite shows higher resistance to CO₂-induced reactions. These findings offer valuable data for optimizing GCS technologies and predicting long-term sequestration outcomes. Full article

The Ti6Al4V alloy is considered the most beneficial of the titanium alloys for use in biomedical applications. However, it corrodes when exposed to various biocompatible fluids. This investigation aims to evaluate the corrosion inhibition performance of the Ti6Al4V in a saline solution (SS) using thiocolchicoside (TCC) drug as an environmentally acceptable corrosion inhibitor. The corrosion assessments were conducted using potentiodynamic polarization curves (PPCs), open-circuit potential (OCP), and electrochemical impedance spectroscopy (EIS) methodologies, supplemented by scanning electron microscopy (SEM), energy-dispersive X-ray (EDS) analysis, atomic force microscopy (AFM), and contact angle (CA) measurements. The outcomes indicated that the inhibitory efficacy improved with higher TCC concentrations (achieving 92.40% at 200 mg/L of TCC) and diminished with an increase in solution temperature. TCC’s physical adsorption onto the surface of the Ti6A14V, which adheres to the Langmuir adsorption isotherm, explains its mitigating power. The TCC acts as a mixed-type inhibitor. The adsorption and inhibitory impact of TCC were examined at various temperatures using PPC and EIS. When TCC is present, the corrosion’s apparent activation energy is higher (35.79 kJ mol⁻¹) than when it is absent (14.46 kJ mol⁻¹). In addition, the correlation between the structural properties of thiocolchicoside (TCC) and its corrosion inhibition performance was systematically analyzed. Density Functional Theory (DFT) calculations were utilized to characterize the adsorption mechanism, supported by Natural Bond Orbital (NBO) analysis and Molecular Dynamics (MD) simulations. The combined computational and electrochemical findings confirm that TCC provides effective and enhanced corrosion protection for the Ti6Al4V alloy in a saline environment. These characteristics provide compelling evidence for the suitability of these pharmaceutical compounds as promising corrosion inhibitors. Full article

Objectives: The potential use of electron density (ED) and effective atomic number (Zeff) derived from dual-energy computed tomography (DECT) as novel quantitative imaging biomarkers for differentiating malignant brain tumors was investigated. Methods: Data pertaining to 136 patients with a pathological diagnosis of brain metastasis (BM), glioblastoma, and primary central nervous system lymphoma (PCNSL) were retrospectively reviewed. The 10th percentile, mean and 90th percentile values of conventional 120-kVp CT value (CTconv), ED, Zeff, and relative apparent diffusion coefficient derived from diffusion-weighted magnetic resonance imaging (rADC: ADC of lesion divided by ADC of normal-appearing white matter) within the contrast-enhanced tumor region were compared across the three groups. Furthermore, machine learning (ML)-based diagnostic models were developed to maximize diagnostic performance for each tumor classification using the indices of DECT parameters and rADC. Machine learning models were developed using the AutoGluon-Tabular framework with rigorous patient-level data splitting into training (60%), validation (20%), and independent test sets (20%). Results: The 10th percentile of Zeff was significantly higher in glioblastomas than in BMs (p = 0.02), and it was the only index with a significant difference between BMs and glioblastomas. In the comparisons including PCNSLs, all indices of CTconv, Zeff, and rADC exhibited significant differences (p < 0.001–0.02). DECT-based ML models exhibited high area under the receiver operating characteristic curves (AUC) for all pairwise differentiations (BMs vs. Glioblastomas: AUC = 0.83; BMs vs. PCNSLs: AUC = 0.91; Glioblastomas vs. PCNSLs: AUC = 0.82). Combined models of DECT and rADC demonstrated excellent diagnostic performance between BMs and PCNSLs (AUC = 1) and between Glioblastomas and PCNSLs (AUC = 0.93). Conclusion: This study suggested the potential of DECT-derived ED and Zeff as novel quantitative imaging biomarkers for differentiating malignant brain tumors. Full article

The objective of this study was to develop novel alloys of the Ti-15Nb-xTa system (x = 0, 10, 20, and 30 wt.%) and to evaluate the effect of tantalum addition on the structure, microstructure, hardness, and elastic modulus for biomedical applications. The ingots were produced using an arc melting furnace under a controlled argon atmosphere. Chemical composition analyses were performed using energy-dispersive spectroscopy (EDS) to determine the alloying element fractions and to conduct chemical mapping. The Thermo-Calc software (https://thermocalc.com/, 4 September 2024) was employed to predict the influence of Ta on the phase transformation temperatures. Structural and microstructural characterizations were performed using X-ray diffraction (XRD) and scanning electron microscopy (SEM). XRD patterns enabled the identification of the phases, the relative volume fractions, and the lattice parameters of the unit cells. As mechanical properties, Vickers microhardness and elastic modulus were measured. The results revealed that increasing Ta content decreased the β-transus temperature but increased the melting temperature of the alloys. Structural and microstructural characterizations indicated that the Ti-15Nb alloy consisted of α′ + α″ phases, Ti-15Nb-10Ta of α″ + β phases, Ti-15Nb-20Ta of α″ + β + ω phases, and Ti-15Nb-30Ta of metastable β phase. Hardness and elastic modulus results exhibited similar behavior: the alloy with the highest fraction of the α″ phase (Ti-15Nb-10Ta) displayed the lowest hardness and elastic modulus, whereas the alloy containing the ω phase (Ti-15Nb-20Ta) presented significantly higher values. Among the studied alloys, Ti-15Nb-10Ta stands out due to its low elastic modulus (57 GPa). In vitro cellular assays demonstrated that Ti-15Nb-Ta alloys promote osteoblast proliferation while exhibiting no cytotoxicity. Full article

Hydrophilic polymer–osmium complexes enhance electron transfer between enzymes and electrodes in biosensors. In this study, hydrophobic poly(4-vinylpyridine) (PVP) was quaternized with 2-bromoethanol to synthesize water-soluble PVP(Q)-C₂H₄OH polymers (MW 60,000 and 160,000). The resulting PVP(Q)-C₂H₄OH-Os(dmo-bpy)₂Cl complexes were verified by UV-Vis, FT-IR, 1H NMR, SEM-EDS, and zeta potential analyses, confirming successful quaternization and osmium coordination with good dispersion stability. Electrochemical tests (cyclic voltammetry, multi-potential step, amperometry) demonstrated that electrodes with quaternized mediators showed greatly enhanced catalytic currents for glucose (0–20 mM), with sensitivities of 6.9791 (MW 60,000) and 6.6279 μA·mM⁻¹·cm⁻² (MW 160,000), respectively, which were 6.6–10.3 times higher than those of non-quaternized polymers. Selectivity tests showed negligible interference from common species such as ascorbic acid, dopamine, uric acid, and serotonin. Continuous glucose monitoring (CGM) electrodes were fabricated by immobilizing the mediator and glucose dehydrogenase on silanized Au electrodes. SEM, scan rate, and impedance analyses confirmed stable binding. The modified electrodes showed strong linearity (R² = 0.992) and high sensitivity (2.56 μA·mM⁻¹·cm⁻²), and good stability, maintaining ~82% activity for seven days. Human plasma testing validated accurate glucose detection (6.05 mM), consistent with physiological levels. Overall, quaternized PVP(Q) mediators significantly improved solubility and electron transfer, enabling the development of a stable, selective glucose sensor suitable for CGM applications. Full article

Background/Objectives: Atrial fibrillation (AF) is a prevalent cardiac arrhythmia associated with significant morbidity, including stroke, heart failure, and increased mortality, necessitating oral anticoagulant (OAC) therapy to reduce thromboembolic risk. However, OACs, including warfarin and non-vitamin K antagonist oral anticoagulants (NOACs), increase the risk of gastrointestinal (GI) bleeding, a serious complication requiring precise risk stratification in the emergency department (ED). Methods: This retrospective cohort study was conducted in the Emergency Department of Balikesir University Hospital in Turkey between 2019 and 2023 and evaluates systemic inflammatory markers as predictors of GI bleeding in AF patients receiving OACs. A total of 155 patients were divided into case (GI bleeding) and control (no GI bleeding) groups, comparing demographics, comorbidities, CHA₂DS₂-VASc and HAS-BLED scores, and inflammatory indices (uric acid/albumin ratio, neutrophil-to-lymphocyte ratio [NLR], platelet-to-lymphocyte ratio [PLR], systemic immune inflammation index [SII]). Results: For patients receiving NOACs, the case group exhibited significantly higher uric acid/albumin ratio, NLR, PLR, and SII (p < 0.05). For patients receiving warfarin, only the uric acid/albumin ratio was significantly elevated (p < 0.001). Hypolipidemia and elevated uric acid were associated with bleeding risk in patients receiving NOACs, while hypoalbuminemia and elevated urea predicted bleeding in patients receiving warfarin. HAS-BLED scores were significantly higher in bleeding groups, unlike CHA₂DS₂-VASc scores. Conclusions: These findings suggest that inflammatory indices, particularly in patients taking NOACs, are associated with GI bleeding risk stratification. Integrating these biomarkers into clinical practice could optimize personalized anticoagulation strategies, reducing morbidity and mortality in AF patients. Full article

Background: Borrelia burgdorferi, the causative agent of Lyme disease, releases outer membrane vesicles (OMVs) that may contribute to infection and modulate the host immune response. Although interest in OMVs is growing, few studies have systematically compared methods for isolating OMVs from B. burgdorferi. Methods: In this study, we evaluated two OMV isolation techniques—standard ultracentrifugation and an ion-exchange chromatography-based ExoBacteria™ kit—and examined how serum supplements (rabbit serum vs. exosome-depleted fetal bovine serum, ED-FBS) influence Bb-OMV yield and composition. Gene expression profiles were assessed using RT-PCR, and specific protein content was identified by Western blot analyses. To assess the ability of Bb-OMVs to interact with host cells, Bb-OMVs were co-cultured with MDA-MB-231 triple-negative breast cancer cells. Results: Transmission electron microscopy confirmed that both methods produced spherical Bb-OMVs with intact membrane bilayers. Ultracentrifugation generated larger vesicles (15–180 nm), while the ExoBacteria™ kit yielded smaller vesicles (<50 nm) with a higher double-stranded DNA (dsDNA) content, and protein levels were similar across samples. Cultures grown with rabbit serum produced more Bb-OMVs and had cleaner backgrounds in the TEM images than those grown with ED-FBS. All Bb-OMV samples lacked intracellular markers (DnaK and 16S rRNA) and consistently expressed the outer surface protein OspA, confirming high purity. All isolated Bb-OMVs were taken up by the cells, as indicated by OspA expression, without detectable 16S rRNA, confirming vesicle internalization without bacterial contamination. Conclusions: These findings indicate that isolated OMVs are biologically active and capable of interacting with mammalian cells, highlighting their potential role in host–pathogen interactions and the broader relevance of OMVs in studying bacterial modulation of mammalian cell behavior. Overall, both isolation methods produced high-quality OMVs, with ultracentrifugation yielding slightly more pure vesicles, emphasizing the importance of selecting appropriate isolation methods and culture conditions for functional OMV studies. Full article

Titanium dioxide is attractive for energy storage due to its abundance, stability, non-toxicity, low cost, and favorable electronic/optical properties. Colossal permittivity (CP) in co-doped TiO₂ is mainly linked to defect structures rather than intrinsic bulk behavior. This work studies the dielectric properties of TiO₂ co-doped with niobium and magnesium, synthesized by solid-state reaction. Grain size effects were examined by varying ball milling parameters of (½Mg½Nb)_0.05Ti_0.95O₂ and then were correlated with structure, morphology, and dielectric response. X-ray diffraction (XRD), infrared spectroscopy (FTIR), scanning electron microscopy and energy-dispersive X-ray spectroscopy (SEM-EDS), X-ray photoelectron spectroscopy (XPS), and impedance spectroscopy (IS) (40 Hz–10⁶ Hz, 150–370 K) were employed for structural, morphological, and electrical characterization. XRD confirmed the rutile phase. For co-doped samples, larger grains yielded higher dielectric constants, reaching high permittivity (ε′ = 429, T = 300 K, f = 10 kHz at 500 rpm for 2 h). Lower loss tangent (tan δ = 0.11, T = 300 K, f = 10 kHz at 200 rpm for 2 h) is linked to Mg segregation at grain boundaries. The most conductive sample showed the highest dielectric constant, suggesting an IBLC polarization mechanism driven by grain boundary effects. XPS confirmed Nb and Mg incorporation, with Ti⁴⁺ dominant and minor Ti³⁺ from oxygen vacancies and surface hydroxylation/defects. Full article

This study presents a sustainable and time-efficient method for producing aerated lightweight concrete (ALC) by addressing two key challenges: long drying times and limited high-silica sand. The proposed approach combines rapid drying, reducing curing time from 24–48 h to less than one hour, with recycled glass powder to enrich locally available silica-poor sand. The concrete mixtures were characterized using scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS), along with experimentally determined key parameters such as compressive strength, dry density, porosity, and thermal conductivity. Comparative testing was conducted using sand samples from the UAE and UK to represent contrasting climatic and geological conditions, silica-poor desert versus silica-rich quartz, to evaluate adaptability and performance. Two mixes were tested: untreated and glass enriched. The modified mix achieved higher compressive strength, better thermal insulation, and lower environmental impact, while rapid drying maintained structural integrity. The method offers a scalable, low-carbon solution aligned with circular economic principles. Full article

Carbon-fiber-reinforced plastic (CFRP) machining by ultrashort-pulse lasers promises high precision but is limited due to the heterogeneous epoxy–carbon fiber structure, which creates heat-affected zones and variable kerf quality. This work investigates synthesized copper hydroxyphosphate as a laser-absorbing additive to improve femtosecond (1030 nm) laser ablation of CFRP. Copper hydroxyphosphate particles were synthesized hydrothermally and incorporated into an epoxy matrix to produce single-ply CFRP laminates. Square patterns (0.5 × 0.5 mm) were ablated with a pulse energy of 0.5–16 μJ. Then, ablated volumes were profiled and materials characterized by SEM and EDS. In neat epoxy the copper additive reduced optimum ablation efficiency and decreased penetration depth, while producing smoother, less porous surfaces. In contrast, CFRP with copper hydroxyphosphate showed increased efficiency and higher penetration depth. SEM and EDS analyses indicate more uniform matrix removal and retention of resin residues on fibers. These results suggest that copper hydroxyphosphate acts as a local energy absorber that trades volumetric removal for improved surface quality in epoxy and enhances uniformity and process stability in CFRP femtosecond laser machining. Full article