Search Results (45,074)

This research analyzes the wavy, axisymmetric flow of a Ree–Eyring non-Newtonian nanofluid, infused with motile microorganisms, within a porous, tapered cylindrical channel under a transverse magnetic field. This investigation presents a theoretical framework that may inform the improvement of energy efficiency and thermal management in biomedical engineering applications, such as drug delivery systems and microfluidic biosensors. The work provides an extended insight by a contribution to the evaluation of entropy generation, explicitly considering the influence of motile microorganisms, thereby bridging a gap in the existing literature. The comprehensive physical model further incorporates the combined effects of Joule heating, viscous dissipation, nonlinear thermal radiation, and chemical reactions. Methodologically, the governing nonlinear equations of the system were rendered tractable under long-wavelength and low-Reynolds-number assumptions and subsequently solved using the numerical Runge–Kutta–Fehlberg technique. The key conclusion is that, based on the present numerical model, careful selection of magnetic field strength and microorganism motility parameters may reduce irreversible energy losses, potentially improving the net usable work in advanced nanofluid transport systems for biomedical applications, subject to experimental validation. The most significant finding reveals that the magnetic field serves as a dual-purpose control parameter: increasing its strength boosts total entropy generation by 20–30% while simultaneously raising the Bejan number, confirming heat transfer as the dominant irreversibility mechanism in the system. Additionally, nanoparticle concentration diminishes substantially with elevated chemical reaction rates and Schmidt numbers, while microorganism density is highly sensitive to the Péclet number, which causes flow disruptions. Full article

Background: Osteochondral lesions of the talus (OLT) remain a challenging condition due to the limited regenerative potential of articular cartilage. Conventional bone marrow stimulation (BMS) techniques often result in fibrocartilage formation with inferior biomechanical properties. This study aimed to evaluate the safety and preliminary clinical efficacy of an arthroscopically assisted, single-stage injection of a heparin-conjugated fibrin hydrogel (HCFH) for OLT treatment. Methods: Twelve patients with symptomatic OLT underwent arthroscopic debridement, microfracturing, and HCFH injection containing autologous mesenchymal stromal cells (MSCs) and growth factors. Safety was assessed through systematic monitoring of adverse events (graded according to Common Terminology Criteria for Adverse Events criteria), wound healing, and serial laboratory inflammatory markers (leukocytes, erythrocyte sedimentation rate, C-reactive protein) during early and late follow-up. Clinical outcomes were evaluated using the Visual Analog Scale (VAS) and American Orthopedic Foot and Ankle Society score (AOFAS) preoperatively and at 6 and 12 months. Morphological assessment was performed using magnetic resonance imaging (MRI) with the modified Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) scoring system, evaluated independently by two blinded musculoskeletal radiologists. Results: No serious adverse events (Grade III–IV) were observed during the 12-month follow-up. All adverse events were mild (Grade I) and self-limited. A transient postoperative elevation in inflammatory markers was observed, returning to clinically acceptable levels by day 14. Significant improvements were noted in pain (VAS decreased from 6.0 to 2.0) and ankle function (AOFAS increased from 70.0 to 90.6) (p < 0.001). MRI demonstrated progressive morphological improvement, with the MOCART score increasing from 34.16 ± 17.1 at 6 months to 75 ± 5.43 at 12 months (p < 0.001). This increase corresponded with imaging features consistent with tissue maturation over time. The favorable MOCART outcomes observed in this study may be explained by the regenerative properties of heparin-conjugated fibrin hydrogels; however, larger randomized controlled trials with longer follow-up are needed to confirm the durability of the regenerated tissue. Interobserver agreement was substantial to almost perfect for MOCART scoring (κ = 0.68–0.84), with perfect agreement observed for surface assessment, bony defect/overgrowth, and cysts. Conclusions: Within the limitations of this study, single-stage HCFH injection demonstrated an acceptable safety profile and favorable preliminary clinical and radiological outcomes at 12 months. These findings suggest potential regenerative capability; however, controlled studies with larger cohorts and longer follow-up are required to determine comparative efficacy and long-term durability. Full article

This study investigated the covalent grafting of ferulic acid (FA) onto high-amylose corn starch (HACS) through controlled moist heat treatment as a strategy to regulate starch structure and digestibility. Fourier transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance (¹H NMR) analyses confirmed the formation of ester linkages between HACS and FA. Scanning electron microscopy (SEM) revealed that FA grafting induced a rougher granule surface and increased porosity, while differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) indicated altered gelatinization behavior and thermal stability. In vitro digestion analysis showed that the rapidly digestible starch content decreased from 23% to 15%, whereas the resistant starch (RS) content increased to 48% after FA grafting. Molecular docking suggested that FA could interact with α-amylase and that covalent modification may reduce enzyme accessibility to starch chains, thereby limiting starch hydrolysis. These findings demonstrate that FA grafting effectively reshapes the structural and digestive properties of HACS and provides a promising approach for developing resistant starch-rich functional food ingredients. Full article

Melancholia remains a severe and complex form of depression. One possible avenue to a better understanding of melancholia and potentially improved methods of treating it, is via examination of the profiles of brain electrical activity of patients suffering from melancholia. However, apart from work using fMRI, relatively little is known about the electrophysiological basis of melancholia despite the potential for this to inform targeted effective treatments such as Transcranial Magnetic Stimulation. To better understand the state of research regarding EEG variables and melancholia, a systematic review was undertaken. Results indicated that there was a large degree of complexity in the association between melancholia and various EEG parameters, and that many specific aspects of brain electrical activity remain under-studied. Suggestions are made for future research. Full article

Calcium leaching increases the hydraulic concrete material’s porosity and the diffusion coefficient, thereby jeopardizing engineering safety. Fly ash and silica fume are commonly used mineral admixtures in hydraulic concrete, and their effects on the material’s leaching characteristics, especially its microstructural and transport properties, require further investigation. In this study, calcium leaching tests were conducted on cement paste (CP), silica fume–cement paste (SF), and fly ash–cement paste (FA) using a 6 mol/L ammonium chloride solution to accelerate the leaching process. Subsequently, a series of quantitative and qualitative analyses was performed on the deteriorated specimens, including phenolphthalein indicator spraying, X-ray diffraction (XRD), nuclear magnetic resonance (NMR), and scanning electron microscopy (SEM). Additionally, the diffusion coefficients of the material at different locations were calculated and analyzed. The results show that partially replacing cement with silica fume or fly ash increases the initial porosity, gel pore content, and initial diffusion coefficients. After 28 days of leaching, compared to the initial values, the porosity increases in the 0–4 mm layer from the leached surface were 83.6% for CP, 11.0% for SF, and 39.0% for FA. The diffusion coefficients increased by factors of 14.3 (CP), 6.1 (SF), and 13.6 (FA), indicating enhanced resistance to leaching. The primary reason for this is that the reactive silica in the admixtures undergoes a pozzolanic reaction with the calcium hydroxide generated by cement hydration, producing additional calcium silicate hydrate (C-S-H) gel, which reduces the capillary pores that would otherwise result from calcium hydroxide decomposition. Full article

Wireless power transfer (WPT) is increasingly used in smart manufacturing, unmanned platforms, and contactless power-supply applications. However, weak coupling, load-dependent impedance drift, and spatial misalignment can shift the resonant condition, leading to unstable output voltage and reduced transfer efficiency. This paper proposes a constant-voltage WPT method that combines a non-uniform winding coupler, parasitic coils, and dynamic capacitor compensation. A composite magnetic coupler with dense outer windings, loose inner windings, and parasitic coils is first developed, and a region-based electromagnetic model is established to characterise self-inductance, mutual inductance, and coupling coefficients. An improved LCC-S compensation network with a dynamic capacitor compensation matrix is then derived to keep the system close to resonant operation at the nominal 85 kHz operating point under load variation and coil-displacement-induced coupling changes. A zero-voltage-switching-angle tracking method with mutual-inductance correction is further introduced to compensate for phase deviation and maintain soft-switching operation through limited switching-frequency adjustment. Experimental validation demonstrates that the system maintains a stable constant-voltage output across a load range of 20–50 Ω and under 5 cm lateral and longitudinal offsets. The measured efficiency remains above 89% and reaches 93.7% under the optimal coupling and load-matching condition. Full article

Melittin (Mel) is a membrane-active peptide with potential anticancer activity, but its direct therapeutic application may be limited by nonspecific toxicity and delivery-related challenges. The study aimed to assess melittin-functionalized magnetic nanoparticles (MNPs-Mel) as a strategy to enhance antitumor activity in Caco-2 cells, with/without magnetic hyperthermia (MH) association. BJ fibroblasts were used as a normal human in vitro cellular model. The effects of free Mel (2.5 µg/mL), MNPs, and MNPs-Mel (50 µg/mL both) + MH (30 min at 355 kHz and 25 kA/m) were assessed using colorimetry (for viability), luminescence (ATP), and spectrophotometry (lactate) following different exposure conditions. The mechanism of apoptosis induction was evaluated by ELISA (caspase 8 and 9 levels). Transmission electron microscopy (TEM) was also used to evaluate nanoparticle morphology and treatment-associated cellular ultrastructural changes. Free Mel reduced viability in both cell lines, with Caco-2 cells showing greater sensitivity at lower concentrations. MNPs (with/without MH) produced limited and less consistent effects, whereas MNPs-Mel significantly reduced Caco-2 viability and ATP levels and increased LDH and caspase 9. MH further enhanced the effects of MNPs-Mel: reduced viability (57–58% of the control at 24 h and 72 h), decreased ATP levels (67% of the control at 24 h and 53% at 72 h), increased LDH levels (206% of the control at 24 h and 301% at 72 h), and induced the mitochondrial apoptotic pathway (caspase 9 increased with 2164% of the control at 72 h). TEM proved the internalization of both MNPs and MNPs-Mel and revealed extensive ultrastructural alterations concerning mitochondria and lysosomes produced by MNPs-Mel, particularly in the Caco-2 cells. These modifications were heavily increased by MNPs-Mel + MH exposure. Overall, these findings demonstrate that Mel functionalization increases the antitumor activity of Mel at lower doses and that MH further potentiates this effect in Caco-2 cells. Full article

Spontaneous imbibition modified by surfactants is a key technology for enhancing shale oil recovery. Currently, relevant studies mainly concentrate on marine shale worldwide, while the pore–fluid coupling characteristics of widely distributed medium-TOC terrestrial shale remain poorly understood. Against this background, this paper takes typical Paleogene terrestrial shale as the research object and integrates N₂/CO₂ adsorption and NMR T₂ spectroscopy to jointly characterize multiscale pore structures and dynamic fluid evolution during imbibition. The results show that the shale is dominated by mesopores in terms of pore volume, while micropores provide most of the specific surface area. The zwitterionic surfactant HPSB can greatly reduce oil–water interfacial tension and alter rock wettability, thereby breaking the high capillary resistance of micropores. During imbibition, water invades macropores first, followed by mesopores and micropores, and the entire process exhibits remarkable nonlinear dynamics controlled by multiscale pores. The 0.15% HPSB solution shows the best effect on activating micropores. This study innovatively quantifies the influence of surfactant concentration on fluid migration across different pore scales and reveals the internal mechanism of staged imbibition and micropore lag activation in terrestrial shale. It not only complements the global research system of shale imbibition theory but also offers practical guidance for the optimization of fracturing fluid systems in mesopore-dominated shale oil reservoirs. Full article

Robust age measurements for isolated neutron stars (NSs) are not easily available. That is why the characteristic age ${\tau }_{\mathrm{ch}}=P/2\dot{P}$ is often used as a proxy. Here, P is the spin period of the NS and $\dot{P}$ is the time derivative of P. Additional assumptions related to the initial properties and spin-down evolution are made to derive ${\tau }_{\mathrm{ch}}$. As a result, it is expected that ${\tau }_{\mathrm{ch}}$ is an upper limit for the real age ${\tau }_{\mathrm{real}}$. Recently, Chrimes et al. presented measurements of kinematic ages ${\tau }_{\mathrm{kin}}$ for several magnetars. Surprisingly, for the majority of these sources, ${\tau }_{\mathrm{kin}}>{\tau }_{\mathrm{ch}}$. We present a simple model that includes a realistic approximation for magnetic field decay in magnetars and a simple phenomenological description of field re-emergence following fallback after the birth of an NS. We demonstrate that this simple model can explain the observed relation ${\tau }_{\mathrm{kin}}>{\tau }_{\mathrm{ch}}$ for a realistic set of parameters. Full article

Florida mosquito control districts are increasingly confronted with severe Culicoides biting midge problems in coastal areas. Yet, there is no clear guidance for integrating Culicoides management into mosquito-focused operations. This study describes population abundance and distribution trends for the biting midge Culicoides furens on a residential island in Cedar Key, Florida. We use multi-year adult trapping data to help develop strategies that may be used by mosquito control districts to target C. furens populations where they are nuisance pests. Trap data from 2005 and 2007 identified seasonal peaks, high spatial heterogeneity, and substantial year-to-year variation, with an 88.3% reduction in trap captures between 2005 and 2007. These findings provide a foundation for integrated Culicoides management strategies where legal mandates, emerging pathogen risks, and taxpayer-driven nuisance complaints may justify expanded Culicoides control activities by Florida’s Mosquito Control Districts. Full article

Natural microbial pigments offer important advantages and are widely studied for food applications. We investigated the biosynthetic pathways, characteristics, and bioactivities of the orange–red pigment produced by Bacillus velezensis YM–3, a strain isolated from the traditional Pixian Douban condiment. Whole-genome sequencing revealed complete pathways for melanin, phytoene, and heme biosynthesis. The purified extracellular pigment was characterized using ultraviolet–visible spectroscopy, Fourier-transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, and ultra-performance liquid chromatography–high-resolution mass spectrometry; it was preliminarily characterized as melanin-like pigment. The pigment was highly soluble in alkaline solutions, moderately soluble in water, and insoluble in common organic solvents. It exhibited strong photostability and remained stable at low temperature, precipitated under acidic conditions, and showed high stability under alkaline environments. Furthermore, the pigment demonstrated in vitro free radical scavenging activity. Hence, this study provides a scientific foundation for exploring the potential utility of B. velezensis YM–3 and its pigment metabolites as functional agents. Full article

All rotating electrical machines are susceptible to vibrations arising from electromagnetic (EM) forces, electrical faults, mechanical defects, imbalance, and structural resonance. In Doubly Fed Induction Generators (DFIGs), such electromechanical vibrations are especially important because they can degrade reliability, increase noise, and lead to severe damage if resonance-prone operating conditions are not identified in time. Although fault diagnosis in DFIGs has been widely investigated using current, voltage, and flux signatures, comparatively fewer studies have examined fault-specific vibration behaviour under stator and rotor interturn faults (ITTFs), particularly through a coupled EM structural framework. In addition, prior vibration-based studies have not examined the influence of end winding ITTFs, its location, severity, and modal interaction investigating resonance risk. This paper considers vibration characteristics of a variable-speed 2.8 MW DFIG used in a grid-connected Type-3 wind turbine unit (WTU) at no-load operating condition. The DFIG is modelled in ANSYS Academic Research v 2022 R2 Maxwell for EM behaviour assessment for ITTFs in both stator and rotor windings along with modal analysis (MA) in ANSYS Workbench to examine the undamped stator and rotor modes over a range of frequencies. This coupled approach enables identification of vibration signatures associated with different ITTF types. The results show the magnetic flux density near faulty end-winding region increases with fault severity and ranges from 4.19 T to 4.39 T in proximity to faulty windings. A dominant modal frequency band of 60–65 Hz is identified, where stator and rotor modes coincide, creating probable resonance conditions. A severe vibration response is observed for single-phase stator ITTF, showing an amplitude of 2116 mm/s at 480 Hz for a larger number of shorted turns, indicating that asymmetric faults can produce stronger EM excitation than multi-phase faults. The main contribution of this paper is demonstration of a fault-specific, MA and vibration-based Condition monitoring system (CMS) implementation workflow for a DFIG. Unlike prior vibration-based studies that primarily focus on general machine vibration, mechanical faults, bearings, etc., this paper links stator and rotor ITTF induced EM excitation to modal characteristics, resonance behaviour, and measurable vibration signatures, establishing vibration analysis (VA) as a practical complementary technique for CMS of ITTFs in DFIGs. Full article

In mesoscopic domain energy models of electrical steel sheets, the demagnetizing field H_d is usually held constant at its domain-wall-complete value throughout magnetization. This treatment overestimates the magnetostatic energy at intermediate states and distorts the simulated hysteresis loop. We introduce a field-dependent coefficient υ_H that scales the magnetostatic energy at each field step. The coefficient is calculated from the aligned-domain area measured by magneto-optical Kerr microscopy and is anchored at the negative coercivity point H = −H_c, where the macroscopic magnetization vanishes and the aligned-domain area S₀ is minimal. The definition follows from the linear relation H_d ≈ N_d·M that holds during domain-wall motion. Measurements in two observation zones of a grain-oriented steel give consistent υ_H curves, confirming the repeatability of the method. When the correction is incorporated into an Assembly Domain Structure Model, the coercivity error drops from 113% to 9–22% relative to the experimental average, with the predicted value falling inside the experimental range, and the remanence error drops from 39.9% to 15–17%. The same correction, applied to a second grain-oriented steel of a different grade, likewise reduces the coercivity and remanence errors (to about 23% and 18%, respectively), confirming that the method is applicable across grades. Full article

Ultrasonic thickness resonance can be effectively used to detect and quantify the level of corrosion in steel nuclear storage containers as well as other corrosion-prone thin-walled structures, such as pipes and storage tanks. Electro-Magnetic Acoustic Transducers (EMATs) have several advantages over more traditional piezoelectric-based transducers; namely, they can be used in a non-contact fashion on robotic platforms, allowing for measurements regardless of surface conditions or temperature. The major challenge of EMAT application is the power required to counteract the low actuation efficiency, which is achieved with a high-power ultrasonic pulse generator and a transformer circuit. Resonance techniques, in which most of the energy is concentrated near structural resonance frequencies, are preferable to improve efficiency of electro-magnetic acoustic measurements. This methodology was applied to 316L stainless steel thin plates subjected to uniform corrosion as well as pitting corrosion imitating different damage scenarios in a nuclear waste container. The resonant peak frequency shift was found to be proportional to the severity of corrosion for minimally corroded samples. However, the complete disappearance of the resonance peak was observed in the samples with severe corrosion damage. The EMAT liftoff distance was studied to quantify its effect on the amplitude, spread, and frequency of resonant peaks. Recommendations for use of EMATs for assessing corrosion damage are presented. The study demonstrates the success of frequency-based detection of corrosion damage in 316L stainless steel used in fabrication of nuclear waste storage containers. Full article

Background and Clinical Significance: Inflammatory myopericardial syndrome is an umbrella term recently introduced by the European Society of Cardiology, which encapsulates the overlap that exists in clinical practice between myocardial and pericardial disease. It has a heterogeneous aetiology and a broad spectrum of severity in terms of its clinical features. Toxoplasma gondii is a rare but recognised infectious cause of myopericarditis and is typically seen in immunocompromised individuals. Case Presentation: We present the case of a young, immunocompetent male, presenting with pleuritic chest pain following a recent flu-like illness. Investigations revealed an acute myocardial injury based on elevated troponin T levels, in the absence of ventricular dysfunction. Toxoplasma immunoserology was consistent with primary toxoplasma infection. The remainder of his viral panel was negative. There was prompt symptom improvement following commencement of treatment with colchicine and a non-steroidal anti-inflammatory agent. Cardiac magnetic resonance imaging post-discharge revealed findings consistent with prior myocarditis. Conclusions: This case is an example of the rare occurrence of toxoplasma myopericarditis in an immunocompetent individual. Cardiac MRI is an invaluable imaging modality used to evaluate myocardial function and tissue characteristics in patients presenting with inflammatory myopericardial syndrome. Full article