Search Results (325)

Background: Critical illness is frequently accompanied by dysregulated glucose homeostasis, resulting in increased glucose variability (GV). Beyond absolute hyperglycemia or hypoglycemia, early glycemic instability may reflect disease severity and metabolic stress in critically ill children. Objective: To evaluate the prognostic value of early GV indices during the first 72 h of pediatric intensive care unit (PICU) admission and to examine their association with organ dysfunction and adverse outcomes. Methods: This retrospective observational study included children admitted to the PICU between October 2022 and July 2024 with a length of stay greater than 72 h. Clinical and laboratory data were extracted from electronic health records. GV indices were calculated from glucose measurements obtained during the first 72 h after admission and included mean absolute glucose change (MAG), glycemic lability index (GLI), standard deviation (SD), coefficient of variation (CV), and average consecutive absolute change percentage (ACACP). Associations with severity of illness and outcome were assessed using correlation analysis, exploratory multivariable logistic regression, and receiver operating characteristic (ROC) analysis. Results: A total of 248 patients were included (mean age 7.1 ± 5.9 years; 143 [57.7%] male; mortality 7.3%), with a mean of 15.9 ± 4.0 glucose measurements per patient during the first 72 h. GV indices were strongly intercorrelated (all p < 0.001) and were associated with PELOD-2 and/or lactate levels (p < 0.05). Non-survivors had higher GV values than survivors. In exploratory multivariable logistic regression, SD (OR 4.82, 95% CI 2.2–10.4, p < 0.001) and PELOD-2 score (OR 1.68, 95% CI 1.3–2.2, p = 0.004) were associated with mortality. In ROC analysis, SD and PELOD-2 showed similarly strong discrimination for PICU mortality, with no significant difference by DeLong testing. GLI (AUROC 0.70, p = 0.004), ACACP (AUROC 0.68, p = 0.005), and CV (AUROC 0.66, p = 0.027) showed fair discrimination, whereas MAG and lactate were not significant predictors. Conclusions: In this single-center retrospective PICU cohort, early glucose variability during the first 72 h of admission was associated with illness severity and PICU mortality. Among the evaluated indices, SD showed the strongest association with mortality and remained associated with outcome together with PELOD-2 in an exploratory model. These findings should be interpreted as associative and hypothesis-generating; prospective multicenter studies with standardized glucose monitoring and formal incremental prediction analyses are required before GV can be incorporated into routine prognostic assessment. Full article

The present study introduces a novel two-step multi-analytical approach for studying lustre ceramics, aiming to minimize damage to valuable artifacts. The method combines a completely non-destructive preliminary micro-X-ray fluorescence (micro-XRF) analysis, providing semi-quantitative information and elemental mapping, with micro-destructive transmission electron microscopy (TEM) for detailed nanoparticle (NP) morphology studies on selected areas. Diffuse reflectance spectroscopy (DRS) is also employed as a non-destructive method to quantify lustre colour. This approach was applied to 20 samples of 9th- to 12th-century AD lustre ceramics from the Deraheib site in Northern Sudan. The research aimed to verify the lustre technique, characterize lustre properties (nanoparticle size, colour), and identify the ceramic production center based on glaze composition. The results from micro-XRF and TEM confirmed the presence of silver (Ag) and copper (Cu) in the lustre, with Ag NPs having a median size of 8 nm. Semi-quantitative micro-XRF analysis of the glaze indicated a composition rich in lead and tin oxides (PbO and SnO₂, 5%–15%) and magnesium oxide (MgO, 3%). This composition strongly correlates with published data for lustre ceramic production in Basra, Iraq, suggesting it as the likely origin, and ruling out Fustat, Egypt. Full article

This study examines the effect of annealing on 135 nm Fe₃O₄ nanospheres and establishes a direct correlation among particle shape, crystallite size, and magnetic properties. Polycrystalline nanospheres and highly crystalline nanocubes with an equivalent diameter/body diagonal of 135 nm were synthesized via solvothermal and thermal decomposition methods, respectively. Scanning electron microscopy (SEM) revealed that the nanospheres developed smoother surfaces and gradually transformed toward a cubic morphology upon annealing, with increasing temperature and duration. Vibrating sample magnetometry (VSM) measurements showed that both saturation magnetization and coercivity increased with annealing as the particles evolved toward cube-like morphology and larger crystallite size, indicating that the magnetic properties of Fe₃O₄ nanoparticles are strongly dependent on crystallite size and shape. Nanospheres annealed between 500 and 850 °C exhibited increases in both crystallite size and saturation magnetization; however, coercivity decreased at 850 °C, where the crystallite size was maximal. Annealing at 700 °C for 12 h resulted in enhanced crystallite size and improved magnetic properties. Prolonged annealing at 700 °C (24 h) yielded the largest crystallite size but led to a significant reduction in saturation magnetization. This study demonstrates a clear correlation between magnetic properties, crystallinity, and morphology in nanoparticles beyond the superparamagnetic size regime (e.g., 135 nm). It further provides a strategy for tuning structural parameters that govern magnetic behavior and establishes an alternative, more facile route to obtain Fe₃O₄ nanospheres with crystallite sizes and magnetic properties comparable to nanocubes obtained via direct synthesis. Full article

The hot deformation behavior of 7050 aluminum alloy was investigated by isothermal compression tests over a temperature range of 250 °C to 450 °C and a strain-rate range of 0.001 s⁻¹ to 1 s⁻¹. The flow stress was strongly dependent on both temperature and strain rate. At a strain rate of 0.1 s⁻¹, increasing the temperature from 250 °C to 450 °C reduced the peak stress by 72.7%. At 450 °C, decreasing the strain rate from 1 s⁻¹ to 0.001 s⁻¹ reduced the peak stress from 66.7 MPa to 14.6 MPa, corresponding to a decrease of 78.1%. Based on the peak stress, an Arrhenius-type constitutive equation was established, with a deformation activation energy of 179.35 kJ mol⁻¹. The predicted peak stresses agree well with the experimental values, giving a correlation coefficient (R²) of 0.98. The processing map indicates that the optimal hot working domain is located at 400–450 °C and 0.001–0.05 s⁻¹. Scanning electron microscopy (SEM) observations showed that increasing temperature promoted the reduction in second-phase particles, with their area fraction decreasing from 5.3% at 250 °C to 1.2% at 450 °C under 0.001 s⁻¹. In comparison, strain rate had a smaller effect on the particle area fraction at 450 °C. Electron backscatter diffraction (EBSD) analysis revealed that high temperature and low strain rate enhanced dynamic recovery and grain-boundary misorientation evolution. The fraction of low-angle grain boundaries (LAGBs) decreased from 71.5% to 38.8% as the temperature increased from 250 °C to 450 °C under 0.001 s⁻¹, and decreased from 48.2% to 38.8% when the strain rate decreased from 1 s⁻¹ to 0.001 s⁻¹ at 450 °C. Full article

High-strength nanofiber yarns exhibit pronounced nonlinear tensile responses arising from their hierarchical fibrous architecture, yet compact constitutive descriptions remain limited. Here, high-strength polyacrylonitrile nanofiber yarns were prepared by post-drawing as-spun yarns above the glass transition temperature, and their aligned, stacked morphology was confirmed by scanning electron microscopy. Monotonic tensile tests at different loading rates were used to quantify the rate-dependent stress–strain response. The tangent modulus derived from the tensile curve varied strongly with strain, confirming clear deviation from linear viscoelasticity. To capture this behavior, two effective models were established: a modified nonlinear three-element model and a structural four-element model incorporating a nonlinear elastic contribution. Closed-form stress–strain expressions were derived for constant strain-rate loading and fitted to experimental data using nonlinear regression. Both models reproduced the measured tensile curves with high accuracy over the investigated loading-rate range, with correlation coefficients close to unity and low fitting errors. The identified parameters were highly consistent between formulations, indicating functional equivalence for the present monotonic tensile dataset. These results provide a compact framework for characterizing and designing hierarchical polymer nanofiber yarns. Full article

Background: Physical inactivity is a major contributor to cardiometabolic disease and mortality. Although mitochondrial dysfunction characterizes overt pathology, whether sedentarism constitutes a distinct and measurable bioenergetic disease state, rather than simply reduced fitness, has not been established. Methods: Nine sedentary (SED) and ten physically active (AC) healthy males (42 ± 14 yr) were studied. Skeletal muscle bioenergetics were assessed using high-resolution respirometry, fluxomics, metabolomics, and protein expression analyses. Whole-body physiology was evaluated using cardiopulmonary exercise and lactate testing (CPELT). Results: At rest, SED exhibited marked reductions in mitochondrial capacity, including Complex I (−36%), Complex II (−28%), electron transport system capacity (−34%), and ATP-synthase-coupled respiration (−30%, all p < 0.01). The most pronounced alteration was a 49% reduction in mitochondrial pyruvate carrier (MPC1) expression, which closely correlated with reduced pyruvate oxidation (−37%, p = 0.006) and lower TCA intermediates. SED also showed reduced MCT1 abundance, impaired fatty-acid oxidation capacity (−32% to −35%), decreased CPT1 activity (−51%), altered cardiolipin composition, and elevated ROS/O₂ flux ratios. During exercise, SED demonstrated lower VO₂max (−38%), reduced fat oxidation (−35%), and higher blood lactate accumulation (>60%, p < 0.001). Mitochondrial function was strongly associated with exercise performance (r = 0.57–0.78, p < 0.01). Conclusions: Healthy sedentary adults displayed a coordinated reduction in tissue-level mitochondrial oxidative capacity, substrate-handling markers, cardiolipin abundance, and metabolic flexibility. These findings should be interpreted as an integrated per-mg skeletal-muscle bioenergetic phenotype in which lower mitochondrial density may account for much of the observed reduction. Within this phenotype, the 49% reduction in MPC1 alongside preserved GLUT4, LDHA, and LDHB abundance represents an outstanding differential observation that future studies with direct mitochondrial-content normalization should test. CPELT-derived fat oxidation and blood lactate responses reflected this tissue-level bioenergetic phenotype, providing candidate noninvasive physiological markers for future longitudinal and interventional studies. Full article

The increasing occurrence of pharmaceutical contaminants in aquatic environments has intensified the demand for sustainable and cost-effective water treatment technologies. This study investigated the conversion of potato peel waste into carbonaceous adsorbents through hydrothermal carbonization (HTC) and conventional pyrolysis (PRYR) for the removal of carbamazepine (CBZ) from synthetic wastewater. Hydrochars and biochars were synthesized under varying processing conditions and characterized using scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), elemental analysis, and Brunauer–Emmett–Teller (BET) surface area analysis. Adsorption experiments were conducted using a 50 mg/L CBZ solution at pH 6, room temperature, and an adsorbent dosage of 1 g/L. The adsorption performance was evaluated after short contact times to assess rapid-removal capability. HTC-derived hydrochars exhibited significantly superior performance compared with pyrolysis-derived biochars, achieving up to 97% CBZ removal and adsorption capacities approaching 50 mg g⁻¹ within 1 min of contact. In contrast, pyrolysis-derived biochars achieved removal efficiencies between approximately 7 and 55% under similar conditions. Correlation analysis between adsorption behaviour and physicochemical properties revealed that adsorption performance was more strongly influenced by surface chemistry, aromaticity, and mesoporosity than by BET surface area alone. FTIR analysis suggested that hydrogen bonding, π–π electron donor–acceptor interactions, and pore filling contributed to CBZ adsorption. HTC hydrochars retained abundant oxygen-containing functional groups that promoted rapid and stable adsorption, whereas pyrolysis-derived biochars exhibited weaker adsorption interactions despite possessing higher surface areas. The findings demonstrate that hydrothermal carbonization provides an effective low-temperature route for valorising potato peel waste into efficient adsorbents for rapid pharmaceutical removal from water and highlight the critical role of adsorbent surface chemistry in determining adsorption performance. Full article

Nickel ferrite (NiFe₂O₄) is one of the most studied inverse-spinel ferrites because it combines moderate saturation magnetization, comparatively high electrical resistivity, chemical stability, and broad synthesis flexibility. Yet the literature shows that the measured structure and magnetism of NiFe₂O₄ are not intrinsic constants; they evolve strongly with dimensionality, size, thickness, strain state, cation distribution, surface spin disorder, and synthesis pathway. This review develops a unified theoretical and literature-based interpretation of how dimensionality reshapes the structural and magnetic behavior of NiFe₂O₄ across bulk ceramics, nanoparticles, one-dimensional nanostructures, polycrystalline thin films, and ultrathin epitaxial films. The review is anchored in the two uploaded nickel ferrite attachments and expanded using internet-sourced journal literature on spinel inversion, surface effects, mechanochemical synthesis, sputtered and pulsed laser deposited thin films, and epitaxial ultrathin-film anomalies. The central novelty of this article is the formulation of a dimensionality-dependent framework in which the observed magnetic response is governed by a competition among three coupled factors: (i) the cation-distribution function, which controls the A–B superexchange balance and therefore the net ferrimagnetic moment; (ii) the microstructural coherence function, which measures how crystallinity, strain, defects, and anti-phase boundaries preserve or degrade exchange continuity; and (iii) the surface/interface spin-order parameter, which quantifies the loss or reconfiguration of magnetic order at free surfaces and buried interfaces. Within this framework, bulk NiFe₂O₄ behaves as a near-equilibrium inverse spinel with relatively stable magnetization, whereas nanoscale NiFe₂O₄ experiences strong spin canting and finite-size suppression due to the growing fraction of disordered surface spins. Thin films introduce a distinct regime in which strain, texture, anti-phase boundaries, substrate mismatch, and growth kinetics determine both anisotropy and magnetization. In ultrathin epitaxial films, off-equilibrium cation redistribution and interface-controlled electronic reconstruction may even generate magnetization values far above bulk expectations. The review also compares major synthesis routes—solid-state reaction, sol–gel, co-precipitation, hydrothermal growth, reactive milling, combustion, pulsed laser deposition, and radio-frequency sputtering—and explains why each route biases the final dimensionality-dependent properties differently. A set of word-style equations is provided to formalize spinel inversion, finite-size suppression, anisotropy scaling, coercivity trends, and superparamagnetic crossover. Beyond summarizing the field, the review proposes a regime map linking dimensionality to characteristic structural defects and magnetic signatures, and it identifies unresolved questions concerning the true origin of enhanced magnetization in ultrathin NiFe₂O₄, the interplay between anti-phase boundaries and strain, and the distinction between intrinsic inversion changes and extrinsic substrate artifacts. The resulting article offers a submission-ready, originality-focused review that positions dimensionality as the master variable governing structure–magnetism correlations in nickel ferrite. Full article

The treatment of high-salinity, low-carbon marine aquaculture wastewater poses significant challenges for biological denitrification. This study systematically evaluated the performance of a polycaprolactone (PCL)-based aerobic denitrification biofilter under varying temperatures (15 °C and 25 °C) and PCL addition levels (282, 564, 846, 1128, and 1410 g). Optimal nitrogen removal, total nitrogen (TN) removal efficiency exceeding 92%, was achieved with 1128 g PCL at 15 °C (HRT 10 h) and 1410 g PCL at 25 °C (HRT 8 h), significantly outperforming the low-PCL baseline treatment. Microbial community analysis revealed that increased PCL dosage promoted the dominance of the hydrolytic genus Flavobacterium over Simplicispira, enhancing polymer degradation capacity and system stability. Metagenomic sequencing further elucidated the complete PCL degradation pathway, wherein hydrolysis products were oxidized to generate NADH and FADH₂, serving as electron donors for denitrification. Key functional genes (narG, nirK, nosZ) and enzymes associated with both PCL decomposition and nitrate reduction were significantly enriched in high-performance reactors (e.g., AT15H6, AT25H6, ET15H10, ET25H10), correlating strongly with observed nitrogen removal rates. By integrating reactor performance with microbial ecology and functional genetics, this work provides a comprehensive “material–microorganism–gene–performance” framework, offering both practical strategies and mechanistic insights for enhancing denitrification in saline aquaculture systems. Full article

The influence of suspension depth and pollutant concentration on the rate and efficiency of photocatalytic degradation was investigated in aqueous TiO₂ suspensions using methyl orange (MO) as a model pollutant. Both the reaction rate and the efficiency increased by more than one order of magnitude upon a relatively small decrease in suspension layer thickness. The reaction rate exhibited a complex N-shaped dependence on dye concentration, deviating from the monotonic behavior predicted by the Eley–Rideal and Langmuir–Hinshelwood mechanisms, as well as from the relationship derived in our previous study. To elucidate the origin of this behavior, nanoparticle aggregation was examined by sedimentation kinetics, low-acceleration centrifugation, and scanning electron microscopy (SEM). The results suggest that the interplay between enhanced dye adsorption and the reduction in the available photocatalyst surface area due to aggregation leads to the appearance of a maximum in the concentration dependence of the reaction rate. The relationship between reaction rate and photocatalytic efficiency was also analyzed. Although both parameters are correlated, efficiency values strongly depend on the selected reaction time interval, which complicates direct comparison between studies employing different experimental protocols. Consequently, the reaction rate appears to be a more reliable parameter for describing photocatalytic kinetics. Full article

One of the main technological challenges in plasma wakefield acceleration (PWFA) research and development is achieving stable and reproducible acceleration. In particular, for PWFA schemes based on particle-driven plasma wave excitation, beam stability and timing jitter are increasingly critical. In these configurations, magnetic or radio-frequency (RF) compression schemes are often used, and the beam time-of-arrival jitter at the end of the linear accelerator can be strongly correlated with the phase noise of RF accelerating structures operated off-crest. For this reason, since 2008, an RF phase fast-feedback system acting within each RF pulse has been successfully implemented at Laboratori Nazionali di Frascati, Istituto Nazionale di Fisica Nucleare (LNF-INFN) at the Sources for Plasma Accelerators and Radiation Compton with Laser And Beam (SPARC_LAB) facility, operating on both S-band ($2.856$ GHz) and C-band ($5.712$ GHz) klystrons. This paper presents the upgrade and optimization of the fast-feedback system for an S-band klystron powered by a pulse-forming network modulator. This technology introduces significantly higher intrinsic phase noise than, for instance, solid state-based modulators. It is therefore essential to minimize such phase fluctuations to keep the machine stability under control. Both the feedback hardware (electronic boards and RF circuitry) and the software (controller and user interface) have been upgraded. Tests performed at SPARC_LAB achieved a reduction in klystron-induced jitter of a factor of 30, reaching values below 15 fs rms on both power plants. Moreover, adding a remote control of the feedback loop enabled a straightforward optimization of the operating point, allowing the phase stability performance to be pushed close to its practical limits. A detailed analysis of RF phase noise measurements with the fast-feedback loop in operation is also presented. Full article

We investigate the time evolution of bipartite quantum correlations in the ground-state hyperfine manifold of the hydrogen atom subjected to an external magnetic field and independent Markovian dephasing. Treating the electron–proton spin pair as an effective two-qubit system, we derive the exact solution of the Lindblad master equation for an X-shaped initial state and quantify the dynamics using three complementary measures: entanglement of formation (through concurrence), quantum steering (through the CJWR inequality) and Bell nonlocality (through normalized CHSH violation). The dynamics are obtained within a unified open-system framework that combines hyperfine interaction, Zeeman splitting, and Markovian dissipation in a single analytically solvable Lindblad model, allowing a complete operator-level characterization of the correlation decay. This exact treatment provides a transparent link between the underlying spectral structure of the Hamiltonian and the observed hierarchy in the robustness of quantum correlations. Our results reveal that all three quantities exhibit damped oscillations whose frequency and decay rate are strongly tuned by the proton magnetic parameter through the Zeeman splitting. While entanglement decays relatively quickly, steering persists noticeably longer and Bell nonlocality proves to be the most fragile, confirming the expected hierarchy of quantum correlations under local dephasing. The external magnetic field emerges as a practical control knob that can extend the lifetime of these resources even in the presence of noise. These findings provide a clear physical picture of how hyperfine coupling, Zeeman effects, and environmental fluctuations jointly govern quantum coherence in atomic spin systems, with direct implications for spin-based quantum technologies and fundamental tests of nonlocality in realistic laboratory settings. Full article

Background/Objectives: Adolescents living with HIV (ALHIV) face compounded health and psychosocial challenges while managing lifelong antiretroviral therapy (ART). Mental health difficulties among ALHIV are strongly associated with suboptimal adherence and disengagement from care. While mental illness is well documented, limited empirical evidence exists on the influence of positive mental wellness on adherence self-efficacy among ALHIV. This study assessed mental wellness among ALHIV and identified key psychosocial predictors of adherence self-efficacy in public healthcare facilities in Cape Town, South Africa. Methods: A cross-sectional survey was conducted among ALHIV (N = 251) aged 10–19 years who were receiving ART at public healthcare facilities across the Cape Town metropole. Participants completed an electronic questionnaire that assessed ten mental wellness domains and adherence self-efficacy. Descriptive statistics were calculated to summarise participant characteristics and mental wellness scores, while Pearson correlations and multiple linear regression were done to identify associations and independent predictors of adherence self-efficacy using SPSS v29. Results: Most participants were aged 15–19 years (76.9%) and diagnosed with HIV at birth (68.9%). Mental wellness scores were high across all domains (M = 3.14–3.71). Hope (M = 3.71), spirituality (M = 3.58), and purpose in life (M = 3.52) were the highest-rated domains. All mental wellness domains were positively correlated with adherence self-efficacy (p < 0.001), with the strongest associations being purpose in life (r = 0.66), self-acceptance (r = 0.66) and resilience (r = 0.66). Hope (p < 0.001), resilience (p = 0.001), purpose in life (p = 0.03) and self-acceptance (p = 0.012) emerged as significant independent predictors. Conclusions: Positive mental wellness and adolescent-centred psychosocial support in routine HIV care may strengthen adherence self-efficacy and support adolescents’ confidence in managing treatment. Full article

Low temperature and low irradiance (LTLI) stress severely limits strawberry growth and productivity during winter protected cultivation. This study investigated the physiological responses of the short-day strawberry cultivar ‘Benihoppe’ to individual and combined LTLI stress and developed a quantitative damage evaluation index. Seedlings were exposed to four treatments for 20 d: control (25/15 °C, 600 μmol m⁻² s⁻¹), single low temperature (LT: 15/5 °C), single low irradiance (LI: 100 μmol m⁻² s⁻¹), and combined stress (LTLI: 15/5 °C, 100 μmol m⁻² s⁻¹). Compared to isolated stress factors, combined LTLI treatment exhibited a statistically verified synergistic damaging effect (two-factor ANOVA, LT × LI p < 0.01) on leaf structure and function. LTLI-treated plants showed severe reductions in leaf area, palisade tissue thickness, chlorophyll content, and net photosynthetic rate (Pn), alongside elevated malondialdehyde (MDA) accumulation. Chlorophyll a fluorescence (OJIP) analysis revealed that LTLI stress strongly blocked the electron transport chain at the PSII acceptor side, increasing the J-step relative variable fluorescence (Vj) and suppressing the performance index (PI). To quantify these impacts, a Low Temperature and Low Irradiance Damage Index (LTLDI) was derived from 12 core physiological and morphological variables. The LTLDI scores demonstrated that LTLI induced severe damage by day 10 (score: 0.69) and extremely severe damage by day 20 (0.87), which were substantially higher than the damage caused by LT (0.58 at 20 d) and LI (0.63 at 20 d) alone. The index reliability was confirmed by its strong correlation (r > 0.9) with key stress markers (Fv/Fm, Pn, and MDA). Overall, combined LTLI stress exacerbates structural degradation and PSII photoinhibition in strawberry leaves. The proposed LTLDI offers a practical, standardized tool for evaluating stress severity, facilitating timely environmental management in greenhouse strawberry production. Full article

High-temperature superconductivity in strongly correlated materials is often accompanied by pseudogap behavior, strange-metal transport, strong phase fluctuations, and reduced superfluid stiffness, particularly in quasi-two-dimensional systems. These features suggest that pairing alone may not determine the onset of global superconductivity. We develop a coordination-based framework in which superconductivity is promoted by the collective organization of internal electronic degrees of freedom coupled to a carrier phase. A minimal lattice model is introduced, combining a U(1) phase sector, an internal coordination field, and an inter-sector coupling. A Landau analysis shows that internal coordination enhances the effective phase stiffness and can destabilize the incoherent state once the coordination amplitude becomes sufficiently large. Monte Carlo simulations of the model confirm that increasing coordination strength enhances phase stiffness and shifts the onset of global coherence to higher temperature. The framework provides a possible organizing interpretation of the separation between pseudogap onset and superconducting coherence, as well as the sensitivity of layered superconductors to reduced dimensionality, competing orders, and vortex-core structure. It is not intended to replace BCS theory, but to extend phase-stiffness-based descriptions to regimes where pairing, local coordination, and global phase coherence are distinct. Full article