Search Results (27)

In this work, we synthesized the Co_0.85Bi_0.15Fe_1.9X_0.1O₄ (X = Ce³⁺, Sm³⁺, Ho³⁺, and Er³⁺) nanoparticles via the auto-combustion method. The cell viability against two breast cancer cells (MDA-MB-231 and T-47D cells) and the PC3 prostate cancer cells were carefully analyzed and correlated with the structural parameters and particle size values as well as the chemical composition. The produced compounds’ morphological and structural characteristics were performed using scanning transmission microscopy (TEM) and X-ray Diffraction (XRD). For all compounds, the analyses of the XRD experimental data revealed a structurally reversed cubic spinel with space group Fd-3m. All of the compounds had crystallites smaller than 45 nm which concorded well with the particle size values deduced from TEM images. Co_0.85Bi_0.15Fe_1.9Ho_0.1O₄ nanoparticles induced a high mortality of breast and prostate cancer cells (MDA-MB-231, T-47D, and PC3) while the Co_0.85Bi_0.15Fe_1.9Sm_0.1O₄ compound (higher particle size) reduced almost 35% of MDA-MB-231 cancer cells. With very low cytotoxicity against normal human cells, the Co_0.85Bi_0.15Fe_1.9Ho_0.1O₄ nanoparticles play a significant role in the elimination of cancer cells. Full article

We report a method for synthesizing different phases of samarium–cobalt particles through microwave-assisted combustion combined with high-temperature reduction and diffusion, and identify the optimal temperature for forming the 1:5 phase using this approach. Initially, the samarium-to-cobalt ratio in a nitrate solution was determined. Using urea as both a reductant and fuel, samarium–cobalt oxides were synthesized via microwave-assisted combustion. The main components of the oxides were confirmed to be SmCoO₃ and Co₃O₄. Subsequently, samarium–cobalt particles were synthesized at various diffusion temperatures. The results indicate that at 700 °C, the oxides were reduced to elemental Sm and Co. As the reduction temperature increased, the alloying of samarium and cobalt occurred, and the particle size gradually increased. At 900 °C, a pure 1:5 phase was formed, with particle sizes of approximately 800 nm, a coercivity of 35 kOe, and a maximum energy product of 14 MGOe. Based on the microwave-assisted combustion method, this study clarifies the transition temperatures of samarium–cobalt phases during the reduction and diffusion process, and further establishes the synthesis temperature for the 1:5 phase, providing new insights into the preparation and development of samarium–cobalt materials and potentially other rare earth materials. Full article

The tetragonal R_1−xZr_x(FeCo)₁₁Ti alloys, where R is a rare earth and Ti a transition metal, are promising candidates for permanent magnets. Sm_1−xZr_x(Fe_0.8Co_0.2)_12−yTi_y (x = 0 and 0.25; y = 1 and 0.7) master alloys were prepared by arc melting under argon atmosphere. Some of the samples were almost single-phase compounds at 1:12, with a very small amount of a-Fe(Co). Partially replacing Sm with Zr produced alloys with small amounts of Sm(FeCo)₂ Laves-type phases. The as-cast ingots were milled using high-energy ball milling (HEBM) for different times in an argon atmosphere and then annealed at 973 K–1173 K at different interval times (15–90 min). After annealing, the sample milled for 4 h contained a large variation of grain size from 2–4 μm to 20 μm or larger, while, after annealing, the other sampled milled for 8 h exhibited grains size in the range of 2–6 μm; therefore, their coercivity was higher, reaching a maximum value of 5.5 kOe for SmFe₉Co₂Ti annealed at 1123 K for 60 min. Coercivity was strongly affected by the annealing temperature and time. The microstructure evolution with emphasis on the particles size during annealing and their correlation with coercivity are herein discussed. Full article

Background/Objectives: The endosomal escape of lipid nanoparticles (LNPs) is crucial for efficient mRNA-based therapeutics. Here, we present a cationic polymeric micelle (cPM) as a safe and potent co-delivery system with enhanced endosomal escape capabilities. Methods: We synthesized a cationic and ampholytic di-block copolymer, poly (poly (ethylene glycol)_4-5 methacrylate_a-co-hexyl methacrylate_b)_X-b-poly(butyl methacrylate_c-co-dimethylaminoethyl methacrylate_d-co-propyl acrylate_e)_Y (p(PEG_4-5MA_a-co-HMA_b)_X-b-p(BMA_c-co-DMAEMA_d-co-PAA_e)_Y), via reversible addition–fragmentation chain transfer polymerization. The cPMs were then formulated using the synthesized polymer by the dispersion–diffusion method and characterized by dynamic light scattering (DLS) and cryo-transmission electron microscopy (CryoTEM). The membrane-destabilization activity of the cPMs was evaluated by a hemolysis assay. We performed an in vivo functional assay of firefly luciferase (Fluc) mRNA using two of the most commonly studied LNPs, SM102 LNP and Dlin-MC3-DMA LNPs. Results: With a particle size of 61.31 ± 0.68 nm and a zeta potential of 37.76 ± 2.18 mV, the cPMs exhibited a 2–3 times higher firefly luciferase signal at the injection site compared to the control groups without cPMs following intramuscular injection in mice, indicating the high potential of cPMs to enhance the endosomal escape efficiency of mRNA-LNPs. Conclusions: The developed cPM, with enhanced endosomal escape capabilities, presents a promising strategy to improve the expression efficiency of delivered mRNAs. This approach offers a novel alternative strategy with no modifications to the inherent properties of mRNA-LNPs, preventing any unforeseeable changes in formulation characteristics. Consequently, this polymer-based nanomaterial holds immense potential for clinical applications in mRNA-based vaccines. Full article

The development and characterization of synthesis techniques for oxide materials based on ceria is a subject of extensive study with the objective of their wide-ranging applications in pursuit of sustainable development. The present study demonstrates the feasibility of controlled synthesis of Ce_1−xM_xO_2−δ (M = Fe, Ni, Co, Mn, Cu, Ag, Sm, Cs, x = 0.0–0.3) in combustion reactions from precursors comprising glycine, polyvinyl alcohol, polyvinylpyrrolidone, polyethylene glycol, and cellulose as organic components. Controlled synthesis is achieved by varying the composition of the precursor, the type of organic component, and the amount of organic component, which allows for the influence of the generation of high-density electrical charges and outgassing during synthesis. The intensity of charge generation is quantified by measuring the value of the precursor–ground potential difference. It has been demonstrated that an increase in the intensity of charge generation results in a more developed morphology, which is essential for the practical implementation of ceria as a catalyst to enhance contact with gases and solid particles. The maximum value of the potential difference, equal to 68 V, is obtained during the synthesis of Ce_0.7Ni_0.3O_2−δ with polyvinyl alcohol in stoichiometric relations, which corresponds to a specific surface area of 21.7 m² g⁻¹. A correlation is established between the intensity of gas release for systems with different organic components, the intensity of charge generation, morphology, and the value of the specific surface area of the samples. Full article

Energy harvesting plays an important role in advancing personalized wearables by enabling continuous monitoring, enhancing wearable functionality and facilitating sustainable solutions. We aimed to develop a flexible piezoelectric energy harvesting system based on inorganic piezoelectric materials that convert mechanical energy into electricity to power a wide range of mobile and portable electronic devices. There is significant interest in flexible piezoelectric energy harvesting systems that use inorganic piezoelectric materials due to their exceptional physical features and prospective applications. Herein, we successfully demonstrated a flexible piezoelectric nanogenerator (PENG) designed by the co-doped rare-earth element ceramics (RE-PMN-PT) embedded in PVDF and PDMS composite film and attained a significant output performance while avoiding electrical poling process. The impact of dielectric characteristics on the electrical output of nanogenerators was investigated, together with the structure of the composites. The Sm/La-PMN-PT particles effectively amplify both the voltage and current output, showcasing their potential to power portable and wearable devices, as demonstrated by their capacity to illuminate LEDs. The maximal output power of 2 mW was correlated with the high voltage (220 V) and current (90 µA) of Sm/La-PMN-PT/PVDF, which demonstrated that the device has the potential for energy harvesting in biomedical applications. Full article

We reported the new synthesis of Sm₂Co₁₇ particles by a microwave-assisted combustion (MACS) method. This process enables the controlled decomposition of Sm(NO₃)₃ and Co(NO₃)₂ into SmCo-O particles, followed by calcium reduction-diffusion. This SmCo-O particle provides an approach for achieving high magnetic properties in Sm₂Co₁₇ magnetic materials. The rhombohedral Sm₂Co₁₇ particles can be incorporated into epoxy resin and oriented, displaying a square-like hysteresis loop. The particles display magnetic properties at room temperature, with a saturation magnetization of 112.3 emu/g, coercivity of 5.6 kOe, and a maximum energy product of 9.4 MGOe. This method improves the synthesis efficiency of rare earth cobalt-based nano-materials, expands the synthesis scope, and provides ideas for the synthesis and applications of other rare earth nano-materials. Full article

Photocatalysis is considered as simple, green, and the best strategy for elimination of hazardous organic contaminants from wastewater. Herein, new broad spectrum photocatalysts based on pure and Sm-doped CuO/ZnO/CuMn₂O₄ ternary composites were simply prepared by co-precipitation approach. The X-ray diffraction results proved the formation of a composite structure. The transmission electron microscope (TEM) images displayed that most particles have a spherical shape with average mean sizes within 26–29 nm. The optical properties of both samples signified that the addition of Sm ions significantly improves the harvesting of the visible light spectrum of CuO/ZnO/CuMn₂O₄ ternary composites. The photocatalytic study confirmed that 97% of norfloxacin and 96% of methyl green pollutants were photo-degraded in the presence of the Sm-doped CuO/ZnO/CuMn₂O₄ catalyst after 50 and 40 min, respectively. The total organic carbon analysis revealed the high mineralization efficiency of the Sm-doped CuO/ZnO/CuMn₂O₄ catalyst to convert the norfloxacin and methyl green to carbon dioxide and water molecules. During three cycles, this catalyst presented a high removal efficiency for norfloxacin and methyl green contaminants. As a dielectric energy storage material, the Sm-doped CuO/ZnO/CuMn₂O₄ ternary composite has large dielectric constant values, mainly at low frequencies, with low dielectric loss compared to a pure CuO/ZnO/CuMn₂O₄ composite. Full article

A new approach to preparing a series of Co/Sm₂O₃ catalysts for hydrogen production by the dry reforming of methane has been developed. The catalyst precursors were synthesized with a simple method, including the evaporation of aqueous solutions of cobalt and samarium nitrates, followed by a short-term calcination of the resulting material. The as-prepared and spent catalysts were characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, temperature-programmed reduction, and thermogravimetric analysis. The content of cobalt in the synthesized materials affects their phase composition and carbonization resistance in the dry reforming of the methane reaction. It has been shown that preheating in N₂ atmosphere produces catalysts that provide a stable yield of hydrogen and CO of 94–98% for at least 50 h at 900 °C. These yields are among the highest currently available for the dry reforming of methane catalysts made from Co-Sm complex oxides. It has been established that the decrease in the amount of cobalt in the catalyst and its preheating to an operating temperature of 900 °C in a nitrogen flow help to prevent the carbonization of the catalyst and the sintering of metal particles. Full article

Perovskite is the largest mineral on earth and has a variety of excellent physical and chemical properties. La_1−xR_xFeO₃ (R = Co, Al, Nd, Sm) were synthesized using the sol-gel method and analyzed by XRD, TG-DTA, and VSM. With the increase in the Co²⁺ doping content, the diffraction peak drifted in the direction of a larger angle. The grain size of La_1−xR_xFeO₃(R = Co) is mainly concentrated between 50.7 and 133.5 nm. As the concentration of Co²⁺ increased, the magnetic loop area and magnetization increased. La_1−xR_xFeO₃(R = Al) is an orthorhombic perovskite structure, the grain size decreased with the increase in Al³⁺ doping concentration, and the minimum crystallite is 17.9 nm. The magnetic loop area and magnetization increased with the increase in Al³⁺ ion concentration. The enclosed area of the M-H curve of the sample decreased, and the ferromagnetic order gradually weakened and tended to be antiferromagnetic, which may be due to the increase in sintering temperature, decrease in the iron oxide composition, and changes in the magnetic properties. Proper doping can improve the magnetization of La_1−xR_xFeO₃(R = Nd), refine the particles, and obtain better magnetic performance. As the Nd³⁺ ion concentration increased, the magnetic properties of the samples increased. Ms of La_0.85Co_0.15FeO₃ prepared by different calcination time increases with the increase in calcination time. As the Sm³⁺ ion concentration increased, the magnetic properties of the samples increased. Proper doping can improve the magnetization of La_1−xR_xFeO₃(R = Sm), refine the particles, and generate better magnetic performance. Full article

Should the decision be made to immobilise the UK Pu inventory through a campaign of Hot Isostatic Pressing (HIP) in a zirconolite matrix, prior to placement in a geological disposal facility (GDF), a suite of disposability criteria must be satisfied. A GDF safety case should be able to demonstrate that post-closure criticality is not a significant concern by demonstrating that such an event would have a low likelihood of occurring and low consequence if it were to occur. In the case of ceramic wasteforms, an effective means of criticality control may be the co-incorporation of a requisite quantity of a suitable neutron absorbing additive, either through co-immobilisation within the host structure or the encapsulation of discrete particles within the grain structure. Following an initial screening of a range of potential neutron absorbing additives, a literature-based assessment of the solid solution limits of a number of potential additives (Gd, Hf, Sm, In, Cd, B) in the candidate zirconolite (CaZrTi₂O₇) wasteform is presented. Key areas of research that are in need of development to further support the safety case for nuclearised HIP for Pu inventories are discussed. Full article

The series of luminescent NaYF₄:Sm³⁺ nano- and microcrystalline materials co-doped by La³⁺, Gd³⁺, and Lu³⁺ ions were synthesized by hydrothermal method using rare earth chlorides as the precursors and citric acid as a stabilizing agent. The phase composition of synthesized compounds was studied by PXRD. All synthesized materials except ones with high La³⁺ content (where LaF₃ is formed) have a β-NaYF₄ crystalline phase. SEM images demonstrate that all particles have shape of hexagonal prisms. The type and content of doping REE significantly effect on the particle size. Upon 400 nm excitation, phosphors exhibit distinct emission peaks in visible part of the spectrum attributed to ⁴G_5/2→⁶H_J transitions (J = 5/2–11/2) of Sm³⁺ ion. Increasing the samarium (III) content results in concentration quenching by dipole–dipole interactions, the optimum Sm³⁺concentration is found to be of 2%. Co-doping by non-luminescent La³⁺, Gd³⁺ and Lu³⁺ ions leads to an increase in emission intensity. This effect was explained from the Sm³⁺ local symmetry point of view. Full article

The influence of samarium, as an additional alloying element, on the morphology and corrosion performance of the Zn-Co-Sm alloy electrodeposited coatings, was investigated by scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM/EDS) and electrochemical impedance spectroscopy (EIS) measurements. The Zn-Co-Sm coatings were electrodeposited from the aqueous solution containing Sm(NO₃)₃, ZnCl₂, and CoCl₂ as the metal ion source. The percentage of Sm in the coating may be very finely tuned by setting electrodeposition parameters, including cathodic current density, glycine concentration in the electroplating solution, and the solution temperature. The coatings with Sm content from 0.5 to 18.5 wt.% were produced. Since low deposition current densities (10–50 mA cm⁻²) were applied, the samples obtained were of good adhesion and compact. The presence of Sm₂O₃ inclusion was verified by XRD as the Sm₂O₃ crystalline phase. Samarium is incorporated in the coatings through the mechanism of oxide/hydroxide formation during the electroreduction of Zn and Co. Corrosion tests in NaCl solution show that the presence of Sm significantly increases the polarization resistance for the corrosion process of Zn-Co-Sm coatings (one order of magnitude, i.e., from ~500 Ω cm² measured without Sm to 2000–3000 Ω cm² with 12 wt.% Sm), giving evidence of the self-healing action that is provided by Sm particles in the coatings. This effect is more pronounced in the case when the coatings contain a higher Sm percentage. Full article

Several metal oxide nanoparticles (NPs) were already obtained by mixing NaOH solution with chloride solution of the corresponding metal to form metal hydroxide or oxide precipitates and wash—dry—calcine the latter. However, the complete list of metal oxide NPs is missing with which this technology works well. The aim of this study was to fill this knowledge gap and to provide a full list of possible metals for which this technology probably works well. Our methodology was chemical thermodynamics, analyzing solubilities of metal chlorides, metal oxides and metal hydroxides in water and also standard molar Gibbs energy changes accompanying the following: (i) the reaction between metal chlorides and NaOH; (ii) the dissociation reaction of metal hydroxides into metal oxide and water vapor and (iii) the reaction between metal oxides and gaseous carbon dioxide to form metal carbonates. The major result of this paper is that the following metal-oxide NPs can be produced by the above technology from the corresponding metal chlorides: Al₂O₃, BeO, CaO, CdO, CoO, CuO, FeO, Fe₂O₃, In₂O₃, La₂O₃, MgO, MnO, Nd₂O₃, NiO, Pr₂O₃, Sb₂O₃, Sm₂O₃, SnO, Y₂O₃ and ZnO. From the analysis of the literature, the following nine nano-oxides have been already obtained experimentally with this technology: CaO, CdO, Co₃O₄, CuO, Fe₂O₃, NiO, MgO, SnO₂ and ZnO (note: Co₃O₄ and SnO₂ were obtained under oxidizing conditions during calcination in air). Thus, it is predicted here that the following nano-oxides can be potentially synthesized with this technology in the future: Al₂O₃, BeO, In₂O₃, La₂O₃, MnO, Nd₂O₃, Pr₂O₃, Sb₂O₃, Sm₂O₃ and Y₂O₃. The secondary result is that among the above 20 nano-oxides, the following five nano-oxides are able to capture carbon dioxide from air at least down to 42 ppm residual CO₂-content, i.e., decreasing the current level of 420 ppm of CO₂ in the Earth’s atmosphere at least tenfold: CaO, MnO, MgO, CdO, CoO. The tertiary result is that by mixing the AuCl₃ solution with NaOH solution, Au nano-particles will precipitate without forming Au-oxide NPs. The results are significant for the synthesis of metal nano-oxide particles and for capturing carbon dioxide from air. Full article

Bimetallic layered double oxide (LDO) NiM (M = Cr, Fe) catalysts with nominal compositions of Ni/M = 2 or 3 were tailored from layered double hydroxides (LDH) using a coprecipitation method to investigate the effects of the trivalent metal (Cr or Fe) and the amount of Ni species on the structural, textural, reducibility, and catalytic properties for CH₄/CO₂ reforming. The solids before (LDH) and after (LDO) thermal treatment at 500 °C were characterized using TGA-TD-SM, HT-XRD, XRD, Raman, and IR-ATR spectroscopies; N₂ physical adsorption; XPS; and H₂-TPR. According to the XRD and Raman analysis, a hydrotalcite structure was present at room temperature and stable up to 250 °C. The interlayer space decreased when the temperature increased, with a lattice parameter and interlayer space of 3.018 Å and 7.017 Å, respectively. The solids fully decomposed into oxide after calcination at 500 °C. NiO and spinel phases (NiM₂O₄, M = Cr or Fe) were observed in the NiM (M = Cr, Fe) catalysts, and Cr₂O₃ was detected in the case of NiCr. The NiFe catalysts show low activity and selectivity for DRM in the temperature range explored. In contrast, the chromium compound demonstrated interesting CH₄ and CO₂ conversions and generally excellent H₂ selectivity at low reaction temperatures. CH₄ and CO₂ conversions of 18–20% with H₂/CO of approx. 0.7 could be reached at temperatures as low as 500 °C, but transient behavior and deactivation were observed at higher temperatures or long reaction times. The excellent activity observed during this transient sequence was attributed to the stabilization of the metallic Ni particles formed during the reduction of the NiO phase due to the presence of NiCr₂O₄, opening the path for the use of these materials in periodic or looping processes for methane reforming at low temperature. Full article