(ZnSn)_1-xCu_xO nanocomposites (NCs) with nanorods and nanosheet morphologies were synthesized by a facile hydrothermal technique. (ZnSn)_1-xCu_xO NCs exhibited a gradual band gap redshift from UV to visible spectral region with increasing Cu-content. The room temperature magnetic hysteresis loop indicated the improvement of room temperature ferromagnetic (RTFM) behavior of (ZnSn)_1-xCu_xO NCs compared with nanostructured ZnSnO NCs induced by the exchange interaction of Cu-bound polarons with the localized spins and free carriers. The (ZnSn)₆₀Cu₄₀O NCs exhibited the highest saturation magnetization (M_s) of 0.539 emu·g⁻¹. Further increase in Cu-content resulted in the deterioration of crystalline domains and the reduction of M_s to 0.259 emu·g⁻¹. This behavior revealed that the electronic and magnetic properties of (ZnSn)_1-xCu_xO NCs were so sensitive to the dopant concentration that need to be utilized for improving their performance as good candidate NCs for spintronic applications.

We report here the FTIR, optical, and magnetic properties of Sn_1-x-yZn_xM_yO_z ceramics with various x, y, and M. The pure samples are called S1, S2, and S3 for ZnO, SnO₂, and SnZn. The co-substituted samples are called S4, S5, S6, and S7 for SnZnFe, SnZnCo, SnZnNi, and SnZnMn, with Zn = 0.50, Sn = 0.25, and M = 0.25. The Young's modulus, was decreased from 5.70 (D/cm²) for S3 to 4.59, 3.14, 2.59, and 3.05 (D/cm²) for S4, S5, S6, and S7. The E_g was decreased from 2.13 eV for S3 to 2.16, 2,2, and 1.6 eV for S4, S5, S6, and S7. The pure samples (S1–S3) exhibit ferromagnetic behavior at 300 K, and combination of paramagnetic and ferromagnetic behaviors at 10K. In contrast, the samples (S4–S7) exhibit a combination of paramagnetic and ferromagnetic behaviours at both temperatures. The Curie temperature (T_c) obtained through zero-field cooling (ZFC) and field cooling (FC) is close to 300 K for S1–S3, S5, S6, 200 K for S4, and 20 K for S7. The real saturated magnetization (M_s) of the ZnO sample was decreased by the addition of SnO₂, and then increased by the addition of Mn, Ni, Fe, and Co sequentially. M_s was increased from 12.31 (emu/g) for S3 at 300 to 16.24, 31.04, 27.27, and 10.49 (emu/g) for S4, S5, S6, and S7, and from 16 (emu/g) to 87, 730, 83, and 29 at 10 K. Remnant magnetization (M_r) decreases with the addition of SnO₂ to ZnO and is not affected by the addition of TMs, just in the case of Co, where it increases. The coercive field decreases, but the switching field increases markedly with the addition of Mn and Ni, transforming the system from a hard magnetization to a soft magnetization system.

Binder-free Mn₂O₃–MoS₂ hybrid composites (HCs) were fabricated using a room-temperature kinetic spray process under low-pressure conditions with various weight ratios of Mn₂O₃–MoS₂ (1:1, 1:2, and 1:4). The effect of the composition ratio on the electrocatalytic activity of Mn₂O₃–MoS₂ HCs toward the oxygen evolution reaction (OER) in an alkaline medium was investigated. The deposited MoS2 exhibits microrods (MRs) morphology, while pure Mn2O3 exhibits nanoflakes (NFs) morphology. The Mn₂O₃–MoS₂ HCs exhibited NFs-decorated MR morphology. Multilayer heterostructure morphology significantly improves the interfacial synergy between various electroactive species that were verified using various spectroscopic techniques such as micro-Raman and X-ray photoemission spectra. As the MoS₂ content in the Mn₂O₃–MoS₂ HCs increased, the
interfacial charge transfer kinetics associated with the reduction in the oxidation barrier potential improved. The Mn₂O₃–MoS₂ HCs with a 1:4 ratio demonstrated the optimum combination for OER with the smallest overpotential of 290 mV @10 mA cm⁻² and Tafel slope of 41 mV dec⁻¹. The long-term OER stability of the fabricated electrocatalysts was verified using chronopotentiometry techniques for 50 h at 50 mA cm⁻²

A detailed study of calcareous nannofossils was conducted on a well-exposed succession encompassing the Cretaceous-Paleogene (K-Pg) boundary interval at Wadi Nukhul, Sinai, Egypt, as a part of the southern Tethyan margin. The nannofossil biostratigraphic data show that the Nukhul succession sustains a complete K-Pg boundary interval. The nannofossil assemblage indicates a shift from cool/oligo-mesotrophic conditions in the late Maastrichtian Micula murus Zone to warm/oligotrophic in the latest Maastrichtian M. prinsii Zone prior to the K-Pg boundary. At the K-Pg boundary, diversity, and total abundance of the calcareous nannofossils remarkably decreased signifying unstable marine conditions. The post-impact assemblage (lowermost part of NP1 Zone) was marked by acme of Cervisiella operculata indicating oligotrophic conditions in the photic zone related to the diminished of the marine primary producers in the lowermost Danian. At the upper portion of NP1 Zone, the assemblage is still dominated by C. operculata, besides the successive occurrence of the small-sized incoming Paleocene taxa Biantholithus sparsus and Neobiscutum romeinii. This pattern was accompanied by increased frequencies of Zeugrhabdotus sigmoides indicating stressful cool/meso-eutrophic surface water conditions signify the initial recovery interval. Upward in the early Danian NP2-NP3 zones, the nannofossil species diversity and total abundance progressively increased. Also, the nannofossil assemblage is characterized by the existence of the new Paleocene oligotrophic indicators like Cruciplacolithus primus, Coccolithus pelagicus, and Ericsonia subpertusa. This probably indicates a tendency toward rebuilding of the biological pump efficiency and, therefore, a full recovery phase was resumed.

Abstract: Here, we have synthesized four series of polyamide-conductive polymers and used them to modify Fe3O4 NPs/ITO electrodes. The ability of the modified electrodes to detect methotrexate (MTX) anticancer drug electrochemically was investigated. Synthesis of the target-conducting polyamides, P1a–d, P2a–d, P3a, P3b, P3d, and P4c-d, based on different aromatic moieties, such as ethyl 4-(2-(4H-pyrazol-4-ylidene)hydrazinyl)benzoate, diphenyl sulfone, diphenyl ether or phenyl, has been achieved. They were successfully prepared in good yield via solution–polycondensation reaction of the diamino monomers with different dicarboxylic acid chlorides in the presence of N-methyl-2-pyrrolidone (NMP) as a solvent and anhydrous LiCl as a catalyst. A model compound 4 was synthesized from one mole of ethyl-4-(2-(3, 5-diamino-4H-pyrazol-4-ylidene)hydrazinyl) benzoate (diamino monomer) (3) with two moles benzoyl chloride. The structure of the synthesized monomers and polymers was confirmed by elemental and spectral analyses. In addition, thermogravimetric analysis evaluated the thermal stabilities of these polyamides. Furthermore, the morphological properties of selected polyamides were examined using an scanning electron microscope. Polyamide/Fe3O4/ITO electrodes were prepared, and the electrochemical measurements were performed to measure the new polyamides’ conductivity and to detect the MTX anticancer drug in phosphate buffer saline using cyclic voltammetry. The polyamides (P3b and P4b)/Fe3O4/ITO electrodes showed the highest sensitivity and reversibility towards MTX.