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In this present work, Zeolites species of aluminosilicate framework was synthesized by sol–gel method with different ratio of Si/Al (1:1, 1:5, 1:10 and 1:15).The prepared samples were studied by XRD, FTIR, TG/DTA, SEM, TEM,EDAX and SAED analysis. X-ray diffraction patterns indicate that the aluminosilicate have preferred orientation growth along (100) plane with mesoporous structure. The presence of major chemical compounds and network of Si–O–Si, Al–O–Al and Si–O–Al were identified by FTIR study. TG/DTA study shows high-thermal stability. SEM picture shows that highly powdery and heterogeneous.TEM analysis shows tiny tight mass of the active delaminated species gathered to form smooth surface. The SAED pattern reveals that platy structure and well-ordered in atomic scale. The gas sensitivity properties of aluminosilicate solid work in the ratio Al/Si = 1, 5, 10 and 15 as a function of operating temperature 30 °C for different ammonia concentrations from 100, 250 and 500 ppm. The ammonia gas-sensing analysis revealed that the Al/Si (10 ratio) showed higher gas response compared with other ratios. Al/Si = 10 exhibited the highest response of 30 when exposed to 500 ppm ammonia gas. The complex impedance of the aluminosilicate shows two distinguished semicircles and the diameter of the arcs got decreased in diameter as the increases the concentration of ammonia. [ABSTRACT FROM AUTHOR]

Herein, the p–PbS/n–Si photodiodes were fabricated by the cost-effective jet nebulizer spray pyrolysis technique. The PbS thin films were deposited at various substrate temperatures from 225 to 300 °C. The impact of substrate temperature on PbS thin films has been systematically investigated by various characteristics techniques. X-ray Diffraction (XRD) reveals that the prepared films are polycrystalline crystal structures of cubic phase with preferential orientation along the (200) plane. Field Emission Transmission Microscopy (FESEM) results indicate that sphere-like morphology changed into a triangle shape with maximum grain size as substrate temperature increased. The energy dispersive X-ray analysis (EDS) with mapping images confirms the existence of Pb and S. The chemical composition of PbS thin films was investigated by X-ray photoelectron spectroscopy (XPS). The UV–Vis absorption spectrum revealed that the bandgap value increased from 2.2 to 2.5 eV by increasing the deposition temperature from 225 to 300 °C. The I–V characteristics of the p–PbS/n–Si diode showed better rectification in dark and outstanding photovoltaic properties when exposed to light. The photoresponsivity of the fabricated diode increased from 2.525 to 18.140 mA/W with increasing the light intensity from 40 to 120 mW/cm2. Our findings showed that p-PbS/n-Si diodes based on PbS elements are promising for photodiode and ultraviolet photodetector applications. [ABSTRACT FROM AUTHOR]

The cholesterol level determination is a significant clinical diagnostic solution for heart and, thrombosis problems. In this work, we examined a novel non-enzymatic cholesterol biosensor using cholesterol oxidase (ChOx) enzyme immobilized on TiO2 nanoparticles influenced by reduced graphene oxide (rGO) - polypyrrole (PPy) (rGO-TiO2/PPy-GCE) nanocomposite was developed on a glassy carbon electrode (GCE) and the higher sensing response with lower detection limits were observed. The electrochemical properties of GCE modified PPy (PPy-GCE) were studied using CV (Cyclic Voltammetry) and DPV (Differential Pulse Voltammetry). The reported sensor exhibited piecewise linearity in the range of 0.1 µM to 1 µM and 1 µM to 600 µM with the sensing response of 61.665 and 0.1466 (2 µA µMxcm) respectively. The detection limits of the sensor were found to be 32 nm. The results were repeatable and reproducible and this sensor can be applied to determine the cholesterol at real sample with satisfactory results. [ABSTRACT FROM AUTHOR]

Hydrogen bond (H-bond) interactions between the two cyclo dipeptides, cyclo(glycyl-glycine) (CGG) and cyclo(glycyl-alanine) (CGA), and water have been studied using molecular dynamics (MD) and quantum chemical methods. The MD studies have been carried out on CGG and CGA in water using fixed charge force field (AMBER ff03) for over 10 ns with a MD time step of 2 fs. The results of this study show that the solvation pattern influences the conformations of the cyclo dipeptides. Following molecular simulations, post Hartree–Fock and density functional theory methods have been used to explore the molecular properties of the cyclo dipeptides in gaseous and aqueous phase environments. The self-consistent reaction field theory has been used to optimise the cyclopeptides in diethyl ether (ϵ = 4.3) and water (ϵ = 78.5), and the solvent effects have been analysed. A cluster of eight water molecules leads to the formation of first solvation shell of CGG and CGA and the strong H-bonding mainly contributes to the interaction energies. The H-bond interactions have been analysed by the calculation of electron density ρ(r) and its Laplacian ▽2ρ(r) at bond critical points using atoms in molecules theory. The natural bond orbital analysis was carried out to reveal the nature of H-bond interactions. In the solvated complexes, the keto carbons registered the maximum NMR chemical shifts. [ABSTRACT FROM AUTHOR]