The electrical conductivity of extrinsically conducting polymer composite systems passes through a transition state known as percolation threshold. A discussion has been made on how different Sigmoidal models (S-models), such as Sigmoidal–Boltzmann (SB), Sigmoidal–Dose Response (SD), Sigmoidal–Hill (SH), Sigmoidal–Logistic (SL), and Sigmoidal–Logistic-1 (SL-1), can be applied to predict the percolation threshold of electrical conductivity for ethylene vinyl acetate copolymer (EVA) and acrylonitrile butadiene copolymer (NBR) conducting composite systems filled with different carbon fillers. An interesting finding that comes from these observations is that the percolation threshold for electrical conductivity determined by SB and SD models are similar, whereas, the other models give different result when estimated for a particular composite system. This similarity and discrepancy in the results of percolation threshold have been discussed by considering the strength, weakness, and limitation of the models. The percolation threshold value for the composites has also been determined using the classical percolation theory and compared with the sigmoidal models. Moreover, to check the universal applicability, these Sigmoidal models have also been tested on results from some published literature. Finally, it is revealed that, except SL-1 model, the remaining models can successfully be used to determine the percolation threshold of electrical conductivity for extrinsically conductive polymer composites.

Two-dimensional superconductors, especially the covalent metals such as borophene, have received significant attention due to their new fundamental physics, as well as potential applications. Furthermore, the bilayer borophene has recently ignited interest due to its high stability and versatile properties. Here, the mechanical and superconducting properties of bilayer-${\mathsf{\delta }}_6$ borophene are explored by means of first-principles computations and anisotropic Migdal–Eliashberg analytics. We find that the coexistence of strong covalent bonds and delocalized metallic bonds endows this structure with remarkable mechanical properties (maximum 2D-Young’s modulus of ~570 N/m) and superconductivity with a critical temperature of ~20 K. Moreover, the superconducting critical temperature of this structure can be further boosted to ~46 K by applied strain, which is the highest value known among all borophenes or two-dimensional elemental materials.

Light-driven heterogeneous photocatalysis has gained great significance for generating solar fuel; the challenging charge separation process and sluggish surface catalytic reactions significantly restrict the progress of solar energy conversion using a semiconductor photocatalyst. Herein, we propose a novel and feasible strategy to incorporate dihydroxy benzene (DHB) as a conjugated monomer within the framework of urea containing CN (CNU-DHBx) to tune the electronic conductivity and charge separation due to the aromaticity of the benzene ring, which acts as an electron-donating species. Systematic characterizations such as SPV, PL, XPS, DRS, and TRPL demonstrated that the incorporation of the DHB monomer greatly enhanced the photocatalytic CO₂ reduction of CN due to the enhanced charge separation and modulation of the ionic mobility. The significantly enhanced photocatalytic activity of CNU–DHB_15.0 in comparison with parental CN was 85 µmol/h for CO and 19.92 µmol/h of the H₂ source. It can be attributed to the electron–hole pair separation and enhance the optical adsorption due to the presence of DHB. Furthermore, this remarkable modification affected the chemical composition, bandgap, and surface area, encouraging the controlled detachment of light-produced photons and making it the ideal choice for CO₂ photoreduction. Our research findings potentially offer a solution for tuning complex charge separation and catalytic reactions in photocatalysis that could practically lead to the generation of artificial photocatalysts for efficient solar energy into chemical energy conversion.

Synthesized titanium oxide nanoparticles (TiO₂-NPs) nanotubes were used for the disinfection of new emerging corona virus-19 (SARS-CoV-2) in this study. The newly synthesized TiO₂-NPs (nanotubes) were characterized by chemical spectroscopic analysis Fourier-transform infrared spectroscopy and ultraviolet FT-IR and UV. The chemical purity and Zeta potential distribution of the TiO₂-NPs (nanotubes) were evaluated to confirm their nano-range, and their surface morphology was determined by scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HR-TEM), and energy dispersive X-ray analysis (EDX). The antiviral activity of the TiO₂-NPs (nanotubes) against SARS-CoV-2 was evaluated using 10% (Dimethyl sulfoxide) DMSO and dist.H₂O using a cytotoxicity assay and inhibitory concentration assay (to determine the cytotoxic half concentration CC₅₀ and half maximal inhibitory concentration IC₅₀). The current results confirmed that TiO₂-NPs exhibit strong anti-SARS-CoV-2 activity at very low cytotoxic concentrations in vitro with a non-significant selectivity index (CC₅₀/IC₅₀ ≤ 1). The obtained results indicate that TiO₂-NPs and nanotubes have potent antiviral activity at a very low concentrations (IC₅₀ = 568.6 ng/mL), with a weak cytotoxic effect on the cellular host (CC₅₀ = 399.1 ng/mL). Thus, we highly recommend the use of TiO₂-NPs (nanotubes) in vitro and in wall coatings as a potent disinfectant to combat SARS-CoV-2 with little irritation of the cellular hosts. Furthermore, we also recommend more and excessive prospective studies on the complexation of natural active or natural compounds with TiO₂-NPs (nanotubes) to minimize their cytotoxicity, enhance their antiviral activity, and increase their inhibition of SARS-CoV-2.

Little information is available on the potential ecotoxicity of nanomaterials in the marine environment. In particular, the aquatic ecotoxicity impact of titanium dioxide (TiO₂) has been rarely reported. To carefully address this issue, we report on the synthesis of TiO₂ NPs using solvothermal process. The structure and morphology of the prepared TiO₂ nanoparticles were characterised using different techniques. To study the potential ecotoxicity effect of TiO₂, antioxidant system of mediterranean bivalves (Mytilus galloprovincialis) was used, measuring three oxidative biomarkers (ROS production, SOD activity and GSH/GSSG level). No considerable effect was found in the digestive glands of any of the groups treated with TiO₂ with concentration gradients ranging from 1 to 100 mg/L. Thus, the level of the superoxide anion, the activity of an antioxidant enzyme superoxide dismutase (SOD) and the GSH/GSSG ratio showed no significantly differences in digestive glands of all treated groups compared to the control. However, slight modifications were observed in the gills at high concentrations. These results demonstrated that TiO₂ appears to exert little toxicity on marine mussels after a short-term exposure at high concentration. However, before considering the use of this nanomaterial in various applications, further complementary studies are required in order to ensure the environmental safety of these NPs.

Applications of medicinal uses of metals and their complexes have been gaining major clinical significance, especially during the COVID-19 pandemic. The ligation behavior of quercetin (Q), a flavonoid, and Zn metal, i.e., the Zn/Q complex, was fully characterized based on molar conductance, infrared (IR) spectra, elemental analysis, electronic spectra, thermogravimetric analysis, proton nuclear magnetic resonance (¹H-NMR), and transmission electron microscopy (TEM) in our lab. Hepatotoxicity was induced by cadmium (CdCl₂). A total of 40 male albino rats were randomly distributed into the following four groups: Control, hepatotoxic group (CdCl₂), Zn/Q-treated group, and group treated with a combination of CdCl₂ and Zn/Q. Serum hepatic enzymes (AST, ALT, and LDH), total protein, and enzymatic and nonenzymatic antioxidant levels were determined. Histology and TEM for hepatic tissues, in addition to the gene expression of SOD as an antioxidant enzyme in the hepatic tissues, were evaluated. The Q/Zn treatment demonstrated potent protective effects against CdCl₂-induced sever oxidative stress and suppressed hepatic toxicity, genotoxicity, liver enzyme disturbances, and structural alterations. In conclusion, the Zn/Q complex produced a high potent antioxidant effect against the oxidative injury and genotoxicity induced by CdCl₂ and could be considered to be a potent ameliorative hepatoprotective agent against CdCl₂ hepatotoxicity, which could be beneficial during the COVID-19 pandemic.