Search Results (1,184)

The increasing demand for lightweight and high-performance brake rotors has led to the exploration of aluminum–metal matrix composites (Al-MMCs) as alternatives to conventional cast iron rotors. This study evaluated the tribological performance of squeeze-cast Al-MMC brake rotors using an AK Master dynamometer test and compared it with that of conventional gray cast iron (GCI) rotors. The Al-MMC rotors demonstrated stable coefficients of friction (CoFs) with reduced wear rates, compared to the GCI rotors. Surface analysis identified the predominant wear mechanisms, including abrasive and oxidative wear. The Al-MMC rotors exhibited sensitivity to pressure and speed, with a CoF range of 0.35–0.47 that decreased at higher pressures and speeds, whereas the GCI rotors maintained a stable CoF range of 0.38–0.44. At elevated temperatures, the GCI rotors displayed superior thermal stability and fade resistance compared to the Al-MMCs, which experienced a 40–60% loss in CoF. Wear analysis indicated material transfer from brake pads to Al-MMC rotors, resulting in protective tribofilm formation, whereas GCI rotors exhibited conventional abrasive wear. These findings highlight the potential of squeeze-cast Al-MMCs for automotive braking applications, offering advantages in weight reduction and wear resistance, but also suggest the need for further material optimization to enhance high-temperature performance and friction stability. Full article

In this paper, a lightweight permanent magnet in-wheel (LW-PMIW) motor is proposed. This research focuses on using a multi-modulation design to enhance the amplitude of the fundamental wave while suppressing high-order harmonics, thereby enabling the motor to achieve high output torque, a light weight, and a high efficiency. Firstly, a combined trade-off factor related to motor mass, losses, and torque is defined specifically to provide guidance for the design. Secondly, a dual-rotor structure is adopted, and a harmonic injection (HI) design is applied to the permanent magnets (PMs). By designing a targeted harmonic injection ratio coefficient, the non-working harmonics of the PM magnetomotive force (MMF) can be weakened. Then, two iron modulating blocks are introduced to asynchronously modulate the PM MMF, which can further enhance the fundamental amplitude and improve the distribution of the airgap magnetic field. Finally, to verify the effectiveness of the multi-modulation design, the electromagnetic performance of the motor is evaluated and analyzed. The analytical and simulation results show that the torque of the proposed motor can reach 35.4 Nm, which is an increase of 19.6% while the torque ripple remains unchanged compared with the initial motor. Meanwhile, the output power increased by 0.37 kW. Hence, the rationality and effectiveness of the motor design are verified. Full article

Rubella is typically a mild viral illness, but it can lead to severe complications when contracted during pregnancy, such as pregnancy loss or developmental defects in the fetus (congenital rubella syndrome). Therefore, it is crucial to develop and maintain protective immunity in women of childbearing age. In this study, we assessed the transcriptional factors associated with rubella-specific immune outcomes (IgG binding antibody and avidity, neutralizing antibody, and memory B cell ELISpot response) following a third MMR vaccine dose in women of reproductive age to identify key factors/signatures impacting the immune response. We identified baseline (Day 0) and differentially expressed (Day 28–Day 0) genes associated with several RV-specific immune outcomes, including the transferrin receptor 2 (TFR2), which is an important factor regulating iron homeostasis and macrophage functional activity, and a close functional homolog of TFR1, the cellular receptor of the New World hemorrhagic fever arenaviruses. We also identified enriched KEGG pathways, “cell adhesion molecules”, “antigen processing and presentation”, “natural killer cell-mediated cytotoxicity”, and “immune network for IgA production”, relevant to immune response priming and immune activation to be associated with RV-specific immune outcomes. This study provides novel insights into potential biomarkers of rubella-specific immunity in women of childbearing age. Full article

Exposure of LIB materials to ambient conditions with some level of humidity, either accidentally owing to imperfect fabrication or cell damage, or deliberately due to battery opening operations for analytical or recycling purposes, is a rather common event. As far as humidity-induced damage is concerned, on the one hand the general chemistry is well known, but on the other hand, concrete structural details of these processes have received limited explicit attention. The present study contributes to this field with an investigation centered on the use of Raman spectroscopy for the assessment of structural modifications using common lithium iron phosphate (LFP) and nickel–cobalt–manganese/lithium–manganese oxide (NCM-LMO) cathodes. The impact of humidity has been followed through the observation of differences in Raman bands of pristine and humidity-exposed cathode materials. Vibrational spectroscopy has been complemented with morphological (SEM), chemical (EDS), and electrochemical analyses. We have thus pinpointed the characteristic morphological and compositional changes corresponding to corrosion and active material dissolution. Electrochemical tests with cathodes reassembled in coin cells allowed for the association of specific capacity losses with humidity damaging. Full article

Poly(L-lactic acid) (PLLA) and iron (Fe) are popular bioresorbable material candidates for biomedical implants. However, PLLA coronary stents are relatively too thick compared to metallic stents when providing the same mechanical strength, while iron degrades too slowly. Recent studies show that PLLA coatings can enhance iron’s corrosion rate, and iron has strong mechanical strength, making PLLA–Fe composites ideal for bioresorbable implants. Although PLLA coatings on iron samples have been studied, research on embedding iron wires in relatively thick PLLA matrices is limited. Moreover, no studies have yet explored 3D-printed metal wire-reinforced PLLA monofilaments for biomedical applications. To address these research gaps and investigate the in vitro degradation profile of PLLA/Fe wire monofilaments for bioresorbable stents, this study first developed a novel polymer filament–metal wire coextrusion 3D printer for printing PLLA/Fe wire monofilaments. In vitro degradation tests were then conducted on both PLLA/Fe and neat PLLA monofilaments at 50 °C. Thereafter, characterizations, including mass loss, pH, surface appearance and morphology, tensile tests, gel permeation chromatography (GPC), and differential scanning calorimetry (DSC), were performed. Results indicated that the overall degradation rate of PLLA/Fe monofilaments was higher than that of PLLA counterparts, while the degradation rate of PLLA matrix was not affected by the embedded iron wire according to molecular weight analysis. Notably, the Young’s modulus and stiffness of PLLA monofilaments were significantly improved by the iron wires during the early stages of degradation, but the reinforcement in tensile strength was negative after immersion due to the poor embedding quality of the iron wires in the PLLA monofilaments. With future improvement of the embedding quality of iron wire, the 3D-printed PLLA/Fe wire composites can have great potential in the development of biomedical devices using the novel 3D printing method, including most types of stents and bone scaffolds. Full article

Ferroptosis, a distinct form of programmed cell death characterized by iron-dependent lipid peroxidation, has emerged as a critical factor in the pathogenesis of various diseases. Given the increasing prevalence of osteoporosis worldwide and the increasing incidence of osteoporosis, understanding the molecular mechanisms underlying bone loss is imperative for developing targeted therapies. Recent evidence suggests that ferroptosis plays a pivotal role in osteoporosis by influencing the balance between osteoblast and osteoclast activity. This review examines the mechanistic basis of ferroptosis and its pathological implications in osteoporosis. By delineating the interplay between ferroptosis and skeletal remodeling, we highlight potential therapeutic strategies aimed at modulating ferroptosis to mitigate osteoporosis progression. Full article

To mitigate the consumption of active sites on co-catalysts by H₂O₂ and to enhance the efficiency and stability of co-catalytic Fenton reactions, an external circulation two-stage packed-bed reactor (ECTPBR) was developed using DPW (diatomite plate@polydopamine@WC) as a co-catalyst to degrade 4-nitrophenol (4-NP). Under suitable conditions, the ECTPBR could achieve over 91.97% 4-NP degradation, with low iron sludge production (11.97 mg/L) and minimal tungsten leaching (3.6363 mg/L). The two-stage strategy enabled spatial separation of Fe³⁺ reduction and Fenton reactions, minimizing the loss of active sites on DPW, ensuring long-term system stability, and reducing the toxicity of 4-NPdegradation products. In addition, external circulation enhanced mass transfer and improved resistance to shock loads. These advantages suggest that the ECTPBR may serve as an effective strategy for applying co-catalytic Fenton reactions in the treatment of toxic and refractory organic wastewater. Full article

Ferroptosis is an iron-dependent form of regulated cell death marked by lipid peroxidation in polyunsaturated phospholipids. In head and neck cancer (HNC), where resistance to chemotherapy and immunotherapy is common, ferroptosis offers a mechanistically distinct strategy to overcome therapeutic failure. However, cancer cells often evade ferroptosis via activation of nuclear factor erythroid 2-related factor 2 (Nrf2), a key regulator of antioxidant and iron-regulatory genes. HNC remains therapeutically challenging due to therapy resistance driven by redox adaptation. This review highlights the ferroptosis pathway—a form of regulated necrosis driven by iron and lipid peroxidation—and its regulation by Nrf2, a master antioxidant transcription factor. We detail how Nrf2 contributes to ferroptosis evasion in HNC and summarize emerging preclinical studies targeting this axis. The review aims to synthesize molecular insights and propose therapeutic perspectives for overcoming resistance in HNC by modulating Nrf2–ferroptosis signaling. We conducted a structured narrative review of the literature using PubMed databases. Relevant studies from 2015 to 2025 focusing on ferroptosis, Nrf2 signaling, and head and neck cancer were selected based on their experimental design, novelty, and relevance to clinical resistance mechanisms. In HNC, Nrf2 mediates resistance through transcriptional upregulation of GPX4 and SLC7A11, epigenetic stabilization by PRMT4 and ALKBH5, and activation by FGF5 and platelet-derived extracellular vesicles. Epstein–Barr virus (EBV) infection also enhances Nrf2 signaling in nasopharyngeal carcinoma. More recently, loss-of-function KEAP1 mutations have been linked to persistent Nrf2 activation and upregulation of NQO1, which confer resistance to both ferroptosis and immune checkpoint therapy. Targeting NQO1 in KEAP1-deficient models restores ferroptosis and reactivates antitumor immunity. Additionally, the natural alkaloid trigonelline has shown promise in reversing Nrf2-mediated ferroptosis resistance in cisplatin-refractory tumors. Pharmacologic agents such as auranofin, fucoxanthin, carnosic acid, and disulfiram/copper complexes have demonstrated efficacy in sensitizing HNC to ferroptosis by disrupting the Nrf2 axis. This review summarizes emerging mechanisms of ferroptosis evasion and highlights therapeutic strategies targeting the Nrf2–ferroptosis network. Integrating ferroptosis inducers with immune and chemotherapeutic approaches may provide new opportunities for overcoming resistance in head and neck malignancies. Full article

Luminous, hot, massive stars can lose mass both through quasi-steady winds driven by line-scattering of the star’s continuum luminosity, and through transient eruptions identified as Luminous Blue Variables (LBVs). This paper compares and contrasts the processes involved in steady vs. eruptive mass loss, with an emphasis on their dependence on the star’s proximity to the classical Eddington limit. For winds, I examine the role of the iron opacity bump in initiating a quasi-continuum-driven outflow, which can induce atmospheric turbulence in O-stars, an envelope inflation cycle in LBVs, or enhanced wind mass loss in WR stars. In contrast, the giant eruptions of eruptive LBVs like $\eta$ Carinae require a sudden addition of energy to the stellar envelope, like that which can occur from stellar mergers. The positive net energy imparted to a substantial fraction (>10%) of the stellar mass leads to sudden ejection that closely follows an analytic exponential similarity solution. Moreover, the rapid rotation and enhanced luminosity of the post-merger star drive a super-Eddington wind. Due to equatorial gravity darkening, this wind is stronger over the poles, sculpting a bipolar structure in the ejected mass, consistent with observations of $\eta$ Carinae’s Homunculus nebula. Full article

This study provides a comparison between magnetic-to-thermal energy conversion efficiency in liquid and gel phases under high-frequency magnetic fields. Magnetite cores (11 ± 2 nm) were tested as water-based ferrofluids and as 5 wt% agar ferrogels, both with and without a biocompatible polydopamine (PDA) shell. A custom two-phase coil switched between rotating (RMF) and alternating (AMF) modes, enabling phase- and coating-dependent effects to be measured at identical field strengths and frequencies (100–300 kHz, 1–4 kA/m). Across all conditions, RMF generated 1.7–2.1 times more specific loss power (SLP) than AMF, and moving from the liquid to the gel phase reduced SLP by 5–8%, indicating that heating is controlled by Néel relaxation with negligible Brownian contribution. SLP rose with magnetic-field amplitude according to a power law, while hysteretic losses remained minimal. PDA improved colloidal stability and biocompatibility without harming the heating performance, lowering SLP by <17%. Within Brezovich limits, the system still exceeded therapeutic hyperthermia thresholds. Thus, in this iron-oxide/PDA system, neither medium viscosity nor the PDA shell’s non-magnetic mass significantly affects thermal energy output, an important finding for translating laboratory calorimetry data into reliable, application-oriented modelling for magnetic hyperthermia. Full article

Yttrium iron garnet (YIG), as a core material in microwave devices, remains a key focus in materials science for performance optimization. In this study, Y₃Fe_4.8Cu_0.1Sn_0.1O₁₂ samples were prepared via the solid-phase method with the co-doping of low-magnetic-anisotropy Cu²⁺ and Sn⁴⁺, combined with hot-press sintering under different conditions. Systematic analyses revealed that hot-press sintering optimized the microstructure, reduced porosity, and improved the compactness to 5.60 g/cm³. The sample hot-pressed sintered at 1200 °C achieved a maximum ε′ of 34, the lowest dielectric loss and a minimal FMR linewidth of 21 Oe, thus holding great potential for applications in high-frequency microwave devices requiring low loss and high integration. This work provides a viable approach to regulating the microstructure, dielectric properties, and magnetic properties of YIG ferrites. Full article

This work presents a method for preparing an Fe₂O₃/MWCNT/Al composite electrode without the use of a binder. Synthesizing the composite material directly on conductive substrates allows one to obtain ready-made supercapacitor electrodes characterized by high values of specific capacity, as well as resistance to numerous charge/discharge cycles. Using an array of multi-walled carbon nanotubes (MWCNTs) as a conductive base for the synthesis of iron oxide allows for the production of a composite material that combines the positive properties of both materials. The Fe₂O₃/MWCNT/Al composite was formed using electrochemical oxidation of the MWCNT/Al material in a mixture of 0.1 M aqueous solution of Fe(NH₄)₂(SO₄)₂ (iron ammonium sulfate) and 0.08 M CH₃COONa (sodium acetate) in a 1:1 ratio. The proposed approaches to fabricating composite electrodes provide excellent performance characteristics, namely high cyclic stability and fast response time. For the first time, an Fe₂O₃/MWCNT/Al composite was obtained using electrochemical oxidation of Fe²⁺ on the surface of MWCNTs grown directly on aluminum foil. The specific capacitance of the obtained composite material reaches 175 F/g at a scanning rate of 100 mV/s. The capacity loss during cyclic measurements does not exceed 25% after 10,000 charge/discharge cycles. Full article

This study investigates the thermal performance of induction motors powered by multilevel H-bridge inverters using a novel pulse-width phase shift triangle modulation (PSTM-PWM) technique. Conventional PWM methods introduce significant harmonic distortion, increasing copper and iron losses and causing overheating and reduced motor lifespan. Through experimental testing and comparison with standard PWM techniques (LS-PWM and PS-PWM), the proposed PSTM-PWM reduces harmonic distortion by up to 64% compared to the worst one and internal motor losses by up to 5.5%. A first-order thermal model is used to predict motor temperature, validated with direct thermocouple measurements and infrared thermography. The results also indicate that the PSTM-PWM technique improves thermal performance, particularly at a triangular waveform peak value of 3.5 V, reducing temperature by around 6% and offering a practical and simple solution for industrial motor drive applications. The modulation order was set to M = 7 to reduce both the losses in the power inverter and to prevent the generation of very high voltage pulses (high dV/dt), which can deteriorate the insulation of the induction motor windings over time. Full article

Background: Fixed-dose combinations have advanced in many therapeutic areas, including otorhinolaryngology, where hearing disorders are increasingly prevalent. Objectives: The present study focuses on developing and evaluating a new capsule combining nicergoline (NIC), piracetam (PIR), and hawthorn extract (HE) for the management of sensorineural hearing loss. Methods: The first phase methodology comprised preformulation studies (DSC, FTIR, and PXRD) to assess compatibility among active substances and excipients. Subsequently, four formulations were prepared and tested for flowability, dissolution behavior in acidic and neutral media, and stability under oxidative, thermal, and photolytic stress. Quantification of the active substances and flavonoids was performed using validated spectrophotometric and HPLC-UV methods. Results: Among the tested variants, the F1 formulation (4.5 mg NIC, 200 mg PIR, 50 mg HE, 2.5 mg magnesium stearate, 2.5 mg sodium starch glycolate, and 240.5 mg monohydrate lactose per capsule) displayed optimal technological properties, superior dissolution in acidic media, and was further selected for evaluation. The antioxidant activity of the formulation was confirmed through the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, Trolox Equivalent Antioxidant Capacity (TEAC), and iron chelation tests, and was primarily attributed to the flavonoid content of the HE. Acute toxicity tests in mice and rats indicated a high safety margin (LD₅₀ > 2500 mg/kg), while ototoxicity assessments showed no adverse effects on auditory function. Conclusions: The developed formulation displayed good stability, safety, and therapeutic potential, while the applied workflow could represent a model for the development of future fixed-dose combinations. Full article

Electromagnetic and magnetic devices are increasingly prevalent in sectors such as transportation, industry, and renewable energy due to the ongoing electrification trend. These devices exhibit nonlinear behavior, particularly under signals rich in harmonics. They require precise and appropriate modeling for accurate sizing. Identifying model-specific parameters, which depend on frequency, is crucial. This article focuses on a specific frequency range where a circuit model with series resistance and inductance, along with a parallel resistance to account for iron losses (${\mathrm{R}}_{\mathrm{iron}}$), is applicable. While the determination of series elements is well documented, the determination of ${\mathrm{R}}_{\mathrm{iron}}$ remains complex and debated, with traditional methods neglecting operating conditions such as magnetic saturation. To address these limitations, an innovative experimental method is proposed, comprising two main steps: determining the complex impedance of the magnetic device and extracting ${\mathrm{R}}_{\mathrm{iron}}$ from the model. This method aims to provide a more precise and representative estimation of ${\mathrm{R}}_{\mathrm{iron}}$, improving the reliability and accuracy of electromagnetic and magnetic device simulations and designs. The obtained values of the iron loss equivalent resistance are different by at least 300% than those obtained by an impedance analyzer. The proposed method is expected to advance the understanding and modeling of losses in electromagnetic and magnetic devices, offering more robust tools for engineers and researchers in optimizing device performance and efficiency. Full article