Magnetite nanoparticles (MNPs) exhibit favorable heating responses under magnetic excitation, which makes them particularly suited for various hyperthermia applications. Herein, we report the detailed self-heating mechanisms of MNPs prepared via the Ko-precipitation Hydrolytic Basic (KHB) methodology. The as-prepared MNPs were fully characterized using various spectroscopic techniques including transmission electron microscopy (TEM), dynamic light scattering (DLS), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), and vibrating sample magnetometry (VSM). MNPs exhibited stable 15 nm quasi-spherical small-sized particles, pure crystalline cubic Fe₃O₄ phases, high saturation magnetizations (Ms = ~40 emu·g⁻¹), and superparamagnetic behavior. In response to alternating magnetic fields (AMFs), these MNPs displayed excellent self-heating efficiencies with distinctive heating responses, even when minimal doses of MNPs were used. Heating efficacies and specific absorption rate (SAR) values as functions of concentration, frequency, and amplitude were systematically investigated. Remarkably, within only a few minutes, MNPs (2.5 mg/mL) showed a rapid dissipation of heat energy, giving a maximum intrinsic loss power (ILP) of 4.29 nHm²/kg and a SAR of 261 W/g. Hyperthermia temperatures were rapidly reached in as early as 3 min and could rise up to 80 °C. In addition, Rietveld refinement, Langevin, and linear response theory (LRT) models were studied to further assess the magnetic and heating mechanisms. The LRT model was used to determine the Néel relaxation time (τ_R = 5.41 × 10⁻⁷ s), which was compared to the Brownian relation time value (τ_B = 11 × 10⁻⁷ s), showing that both mechanisms are responsible for heat dissipated by the MNPs. Finally, the cytotoxicity assay was conducted on aqueous dispersions of MNPs, indicating their biocompatibility and low toxicity. Our results strongly suggest that the as-prepared Fe₃O₄ MNPs are promising vehicles for potential magnetically triggered biomedical hyperthermia applications.

In this report, the heating efficiencies of γ-Fe₂O₃ and hybrid γ-Fe₂O₃-TiO₂ nanoparticles NPs under an alternating magnetic field (AMF) have been investigated to evaluate their feasible use in magnetic hyperthermia. The NPs were synthesized by a modified sol-gel method and characterized by different techniques. X-ray diffraction (XRD), Mössbauer spectroscopy and electron microscopy analyses confirmed the maghemite (γ-Fe₂O₃) phase, crystallinity, good uniformity and 10 nm core sizes of the as-synthesized composites. SQUID hysteresis loops showed a non-negligible coercive field and remanence suggesting the ferromagnetic behavior of the particles. Heating efficiency measurements showed that both samples display high heating potentials and reached magnetic hyperthermia (42 °C) in relatively short times with shorter time (~3 min) observed for γ-Fe₂O₃ compared to γ-Fe₂O₃-TiO₂. The specific absorption rate (SAR) values calculated for γ-Fe₂O₃ (up to 90 W/g) are higher than that for γ-Fe₂O₃-TiO₂ (~40 W/g)_, confirming better heating efficiency for γ-Fe₂O₃ NPs. The intrinsic loss power (ILP) values of 1.57 nHm²/kg and 0.64 nHm²/kg obtained for both nanocomposites are in the range reported for commercial ferrofluids (0.2–3.1 nHm²/kg). Finally, the heating mechanism responsible for NP heat dissipation is explained concluding that both Neel and Brownian relaxations are contributing to heat production. Overall, the obtained high heating efficiencies suggest that the fabricated nanocomposites hold a great potential to be utilized in a wide spectrum of applications, particularly in magnetic photothermal hyperthermia treatments.

O1 Regulation of genes by telomere length over long distances

This study reports a simple new technique for the preparation of novel hexagonal-shaped mixed metal oxides (MMO) nanorods using Zn/Al-layered double hydroxide (LDH) as a precursor for dye-sensitized solar cell (DSSC) application. The effect of the Zn to Al molar ratio demonstrated a sound correlation between the obtained nanorods’ diameter and the fabricated DSSCs efficiency. Additionally, the optical behavior of the fabricated MMO film as well as the absorption enhancement due to the utilized dye are also demonstrated; a cut-off phenomenon at around 376 nm corresponds to the attained hexagonal nanorods. The open-circuit voltage augmented noticeably from 0.6 to 0.64 V alongside an increase in the diameter of nanorods from 64 to 80 nm. The results indicated that an increment in the diameter of the nanorods is desirable due to the enhanced surface area through which a higher amount of dye N719 was loaded ($0.35 \mathrm{mM}/{\mathrm{cm}}^2$). This, in turn, expedited the transport of electrons within the MMO matrix resulting in an advanced short-circuit current. Of the devices fabricated, ZA-8 exhibited the highest fill factor and efficiency of 0.37% and 0.69%, respectively, because of its boosted short-circuit current and open-circuit voltage.

In this article, an in-depth optical investigation of Zn(Al)O-mixed metal oxide (MMO) film using Zn/Al-layered double hydroxide (LDH) was elucidated through co-precipitation and spin coating techniques. The field emission scanning electron microscopy (FE-SEM) analysis revealed the occurrence of a vertically aligned sheet-like structure with a thickness of 60 nm for pristine LDH, which further reduced to 45 nm after calcination at 300 °C. Additionally, pristine LDH showed multiple optical bandgaps of 5.18, 3.6, and 3.2 eV. Moreover, a good agreement of the obtained optical bandgaps was attained between both utilized methods, ultraviolet-visible light (UV-Vis), and photoluminescence (PL) spectroscopies. The optical bandgap decreased at higher calcination temperatures, which indicates the active role of the applied post-fabrication process on the optical profile of the deposited MMO film/s. The demonstrated transmittance spectra of the deposited MMO films exhibited a transparency between 85% and 95%; this indicates the usefulness and consistency of the proposed film for transparent conductive oxide (TCO) based optoelectronic applications.

In this report, we discuss the preparation of undoped and (Fe,Co) co-doped ZnO nanocomposites via an ultrasonicated probe, which were both under UV irradiation for 12 h and annealed at 400 °C for four hours in ambient air. Here, we investigated the different concentration of dopant transition metals (ZnO-Fe_1-x-Co_x) (x = 0.03, 0.05, and 0.07). X-ray diffraction (XRD) analyses confirmed the nanophase, crystallinity, good uniformity, and around 28 nm core sizes of all of the (ZnO-Fe_1-x-Co_x) as-synthesized composites with different rates. The optical properties of ZnO doped with a high percent of Fe nanoparticles displayed an increase in absorption in the UV region and a slight decrease in the energy band gap to 3.13 eV. Magnetic measurements revealed that doping enhanced the ferromagnetism of ZnO. Recent studies which aimed to improve the optical and magnetic properties of metal oxides, the most important of which being zinc oxide, have allowed their applications to diversify and multiply in the medical, industrial, and electronic fields.