Co2FeO4@rGO composite: Towards trifunctional water splitting in alkaline media

Development of efficient, low cost and multifunctional electrocatalysts for water splitting to harvest hydrogen fuels is a challenging task, but the combination of carbon materials with transition metal-based compounds is providing a unique and attractive strategy. Herein, composite systems based on cobalt ferrite oxide-reduced graphene oxide (Co₂FeO₄) @(rGO) using simultaneous hydrothermal and chemical reduction methods have been prepared. The proposed study eliminates one step associated with the conversion of GO into rGO as it uses direct GO during the synthesis of cobalt ferrite oxide, consequently rGO based hybrid system is achieved in-situ significantly, the optimized Co₂FeO₄@rGO composite has revealed an outstanding multifunctional applications related to both oxygen evolution reaction (OER) and hydrogen counterpart (HER). Various metal oxidation states and oxygen vacancies at the surface of Co₂FeO₄@rGO composites guided the multifunctional surface properties. The optimized Co₂FeO₄@rGO composite presents excellent multifunctional properties with onset potential of 0.60 V for ORR, an overpotential of 240 mV at a 20 mAcm^?2 for OER and 320 mV at a 10 mAcm^?2 for HER respectively. Results revealed that these multifunctional properties of the optimized Co₂FeO₄@ rGO composite are associated with high electrical conductivity, high density of active sites, crystal defects, oxygen vacancies, and favorable electronic structure arisinng from the substitution of Fe for Co atoms in binary spinel oxide phase. These surface features synergistically uplifted the electrocatalytic properties of Co₂FeO₄@rGO composites. The multifunctional properties of the Co₂FeO₄@ rGO composite could be of high interest for its use in a wide range of applications in sustainable and renewable energy fields.     

Eco-friendly tape casting of borosilicate glass/Al2O3 sheets for LTCC applications

This work reports the innovative development of a borosilicate glass/Al₂O₃ tape for LTCC applications using an eco-friendly aqueous tape casting slurry. Polyvinylpyrrolidone (PVP) and polyacrylic acid (PAA) were the respective dispersants, while carboxymethyl cellulose (CMC) and styrene acrylic emulsion (SA) were the respective binders. The results showed that PVP was more suitable than PAA as the dispersant for the aqueous casting slurry, and that 1.5 wt% PVP would achieve well dispersion of CABS glass/Al₂O₃ powder in the aqueous slurry. Moreover, a small amount of 2.0 wt% CMC binder could yield smooth CABS glass/Al₂O₃ tapes crack free. A high-quality CABS glass/Al₂O₃ tape with a smooth surface was made from an aqueous slurry containing 1.5 wt% PVP dispersant, 2.0 wt% CMC binder, and 2.0 wt% PEG-400 plasticizer. The density, tensile strength, and surface roughness of the green tape were 2.05 g/cm³, 0.87 MPa, and 148 nm, respectively. The resulting CABS glass/Al₂O₃ composites sintered at 875 °C exhibited a bulk density of 3.14 g/cm³, a dielectric constant of 8.09, a dielectric loss of 1.0 × 10^?3, a flexural strength of 213 MPa, a thermal expansion coefficient of 5.30 ppm/^°C, and a thermal conductivity of 3.2 W m^?1 K^?1, thus demonstrating its broad prospects in LTCC applications.     

Essential (Mg,Fe, Zn and Cu) and Non-Essential (Cd and Pb) Elements in Predatory Insects (Vespa crabro and Vespa velutina): A Molecular Perspective

The recent introduction of the Asian yellow-legged hornet, Vespa velutina, into Europe has raised concern regarding the threat to honeybees and the competition with the European hornet, Vespa crabro. The aim of this study was to investigated essential (Mg, Fe, Zn, Cu) and non-essential (Cd and Pb) elements in these two species. Element concentrations were determined in the whole body and separately in the head, thorax and abdomen using atomic absorption spectrometry (AAS). The changes in essential element concentration and speciation during metamorphosis were also studied using size exclusion chromatography followed by AAS and proteomic analysis. In both species, the essential elements were more concentrated in the abdomen due to the presence of fat bodies. Magnesium, Fe and Zn concentrations were significantly higher in V. crabro than in V. velutina and could have been related to the higher aerobic energy demand of the former species required to sustain foraging flight. Low concentrations of Cd and Pb were indicative of low environmental exposure. The concentration and speciation of essential elements, particularly Fe, varied among the developmental stages, indicating a modification of ligand preferences during metamorphosis. Overall, the results in the present study provide a better understanding of the hornet metal metabolism and a foundation for additional studies.     

Tailored-Made Polydopamine Nanoparticles to Induce Ferroptosis in Breast Cancer Cells in Combination with Chemotherapy

Ferroptosis is gaining followers as mechanism of selective killing cancer cells in a non-apoptotic manner, and novel nanosystems capable of inducing this iron-dependent death are being increasingly developed. Among them, polydopamine nanoparticles (PDA NPs) are arousing interest, since they have great capability of chelating iron. In this work, PDA NPs were loaded with Fe³⁺ at different pH values to assess the importance that the pH may have in determining their therapeutic activity and selectivity. In addition, doxorubicin was also loaded to the nanoparticles to achieve a synergist effect. The in vitro assays that were performed with the BT474 and HS5 cell lines showed that, when Fe³⁺ was adsorbed in PDA NPs at pH values close to which Fe(OH)₃ begins to be formed, these nanoparticles had greater antitumor activity and selectivity despite having chelated a smaller amount of Fe³⁺. Otherwise, it was demonstrated that Fe³⁺ could be released in the late endo/lysosomes thanks to their acidic pH and their Ca²⁺ content, and that when Fe³⁺ was co-transported with doxorubicin, the therapeutic activity of PDA NPs was enhanced. Thus, reported PDA NPs loaded with both Fe³⁺ and doxorubicin may constitute a good approach to target breast tumors.     

Anisotropic thermal expansion and ionic conductivity of a crystal-oriented,Mg2+-conducting NASICON-type solid electrolyte

Multivalent ion-conducting ceramics are required for the manufacture of high-safety, high-capacity rechargeable batteries. However, the low ionic conductivity of solid electrolytes and discrepancies in the thermal expansion between the battery components limit their widespread application. Furthermore, anisotropic thermal expansion in crystals during battery manufacturing and the charge-discharge cycles causes the formation of microcracks, which degrade the battery performance. The physical properties of ceramic materials with anisotropic crystal structures can be modified by varying the crystallographic orientation of their grains. In this study, a co-precipitation approach was used to synthesize an Mg²⁺-conducting (Mg_0.1Hf_0.9)_4/3.8Nb(PO₄)₃ solid electrolyte, and the grain orientation in the bulk sample was controlled using strong magnetic fields during the slip casting process. The results showed that inducing an orientation along the c-axis enhanced the apparent ionic conductivity of the bulk sample. It was also observed that (Mg_0.1Hf_0.9)_4/3.8Nb(PO₄)₃ crystal has a negative volumetric thermal expansion despite a positive linear thermal expansion along its c-axis. By adjusting the c-axis orientation of the grains, (Mg_0.1Hf_0.9)_4/3.8Nb(PO₄)₃ electrolytes with negative or positive linear thermal expansion coefficient have been produced. The findings of this study suggest that solid-electrolytes with negative, positive, or zero linear thermal expansion can be produced to create more compatible and higher-performance solid-state devices.     

硫磷混合酸溶样重铬酸钾容量法测定全铁

介绍了硫磷混合酸溶样重铬酸钾容量法测定矿石中铁含量的方法和步骤。重点讨论了一线生产中的质量控制。     

Hierarchical electromagnetic absorption in micro-waveguide stuffed with magnetic media for resin-based composites of graphene nanosheets and manganese oxides

Waveguide configurations of hierarchical system are proposed as new microstructures for composites in absorbing enhancement. Supercritical fluid (SCF) one-pot exfoliation of layered graphite and manganese oxide mixing materials is developed to obtain a hierarchical system, containing graphene nanosheets (GNS) and exfoliated manganese oxides (EMO) in different sizes. Composites with GNS–EMO embedded in epoxy resin matrix are produced for a design of dielectric and magnetic loss integrated absorber. Volume fraction of GNS–EMO in composites is given for an optimal quantity of resin epoxy in fixation and formation. The effect of mixing ratios between electric and magnetic components is provided for the design of dielectric and magnetic loss integrated absorbers. Frequency shifting phenomena are revealed in the component adjusting course. Excluding the offsetting sizes, reflection loss of composites is enhanced as thickness increases. Synergistic effect of electric and magnetic coordinated materials demonstrates the superiority of micro-waveguide structures in GNS–EMO composite absorber.     

Developmental and Reproductive Effects of Iron Oxide Nanoparticles in Arabidopsis thaliana

Increasing use of iron oxide nanoparticles in medicine and environmental remediation has led to concerns regarding exposure of these nanoparticles to the public. However, limited studies are available to evaluate their effects on the environment, in particular on plants and food crops. Here, we investigated the effects of positive (PC) and negative (NC) charged iron oxide (Fe₂O₃) nanoparticles (IONPs) on the physiology and reproductive capacity of Arabidopsis thaliana at concentrations of 3 and 25 mg/L. The 3 mg/L treated plants did not show evident effects on seeding and root length. However, the 25 mg/L treatment resulted in reduced seedling (positive-20% and negative-3.6%) and root (positive-48% and negative-negligible) length. Interestingly, treatment with polyethylenimine (PEI; IONP-PC coating) also resulted in reduced root length (39%) but no change was observed with polyacrylic acid (PAA; IONP-NC coating) treatment alone. However, treatment with IONPs at 3 mg/L did lead to an almost 5% increase in aborted pollen, a 2%–6% reduction in pollen viability and up to an 11% reduction in seed yield depending on the number of treatments. Interestingly, the treated plants did not show any observable phenotypic changes in overall size or general plant structure, indicating that environmental nanoparticle contamination could go dangerously unnoticed.     

Mutagenic Effects of Iron Oxide Nanoparticles on Biological Cells

In recent years, there has been an increased interest in the design and use of iron oxide materials with nanoscale dimensions for magnetic, catalytic, biomedical, and electronic applications. The increased manufacture and use of iron oxide nanoparticles (IONPs) in consumer products as well as industrial processes is expected to lead to the unintentional release of IONPs into the environment. The impact of IONPs on the environment and on biological species is not well understood but remains a concern due to the increased chemical reactivity of nanoparticles relative to their bulk counterparts. This review article describes the impact of IONPs on cellular genetic components. The mutagenic impact of IONPs may damage an organism’s ability to develop or reproduce. To date, there has been experimental evidence of IONPs having mutagenic interactions on human cell lines including lymphoblastoids, fibroblasts, microvascular endothelial cells, bone marrow cells, lung epithelial cells, alveolar type II like epithelial cells, bronchial fibroblasts, skin epithelial cells, hepatocytes, cerebral endothelial cells, fibrosarcoma cells, breast carcinoma cells, lung carcinoma cells, and cervix carcinoma cells. Other cell lines including the Chinese hamster ovary cells, mouse fibroblast cells, murine fibroblast cells, Mytilus galloprovincialis sperm cells, mice lung cells, murine alveolar macrophages, mice hepatic and renal tissue cells, and vero cells have also shown mutagenic effects upon exposure to IONPs. We further show the influence of IONPs on microorganisms in the presence and absence of dissolved organic carbon. The results shed light on the transformations IONPs undergo in the environment and the nature of the potential mutagenic impact on biological cells.     

Effect of Li2O on the crystallization behavior of CaO-Al2O3-SiO2-Li2O-Ce2O3 mold slags

The effect of Li₂O on the crystallization properties of CaO-Al₂O₃-SiO₂-Li₂O-Ce₂O₃ slags was investigated. With increasing the Li₂O content, LiAlO₂ and CaCeAlO₄ were the main crystalline phases. LiAlO₂ formed for the charge compensating of Li⁺ ions to [AlO₄^5?]-tetrahedrons, and CaCeAlO₄ formed as a result of the charge balance of Ce³⁺ ions, Ca²⁺ ions, and [AlO₆^9?]-octahedrons. Increasing the content of Li₂O to 10%, the crystallization temperature was the highest, and the incubation time was the shortest. The crystallization ability was strong due to the three factors of strengthening the interaction between ions and ion groups, decreasing the polymerization degree, and increasing the melting temperature. Further increasing the content of Li₂O, the crystallization performance was obviously suppressed, because the melting temperature and the force between the cations and the anion groups decreased.