Green Synthesis of Iron Oxide Nanoparticle Using Coffee Seed Extract and Its Antibacterial Activity

The discovery of reliable and green processes for metal oxide nanoparticles synthesis is particularly crucial and exhibits huge potential in various applications. Thus, in this paper, a fast, single step and environmental-friendly method to synthesize iron oxide nanoparticles (Fe2O3-NPs) by bio-reduction of iron salts Fe2+ and Fe3+ under the presence of coffee seeds (CS) aqueous extract was demonstrated. The characteristics of the synthesised Fe2O3-NPs were investigated by using X-ray diffraction (XRD) and ultraviolet-visible (UV-Vis) spectrophotometry techniques. The XRD result revealed that the Fe2O3-NPs produced display highly crystalline property with a cubic structure and the average size of the resulted particle is ranging from 23.2 nm to 37.5 nm. Additionally, the energy band gap (Eg) calculated also showed that maghemite (γ-Fe2O3) nanoparticles was successfully synthesised by using CS extract. The resulted nanoparticles are highly feasible in the inhibition of the growth of pathogenic microorganism.

Synthesis and Liquid Crystalline Properties of Low Molecular Weight Bis-Chalcone Compounds

Aim: In this paper, we report on the synthesis and liquid crystalline properties of some low molecular weight bis-chalcone compounds derived from acetone, cyclopentanone and cyclohexanone mesogenic cores. Background: Structurally bis-chalcones belong to a broader family of chalcone compounds. Chalcone is a compound that consists of two aromatic rings linked by an unsaturated objective. Liquid crystalline chalcones are prepared by aliphatic chain substituents on two aromatic rings. Chalcones are well studied for their mesomorphic properties. Compared to a large number of chalcone based LCs reported, only a few articles have been published on the mesomorphic properties of bis-chalcone compounds. The target compounds of the present study varied not only in their central core but also in number and position of terminal aliphatic chain substitutiona key structural unit in deciding the liquid crystalline properties of a compound. Method: All target compounds were synthesized in good yield by base catalyzed Claisen-Schmidt condensation reaction. Molecular structures were confirmed by FT-IR, 1H NMR, 13C NMR, and mass spectroscopic methods. Liquid crystalline property of these compounds was evaluated using polarizing optical microscopy and differential scanning calorimetry. Results: Although none of the acetone based compounds exhibited mesomorphism, cyclopentanone and cyclohexanone based compounds with octyloxy chain at para position on either side of the dibenzylidine ring stabilized liquid crystalline smectic (SmA and SmC) and nematic (N) phases. The observed structure-liquid crystalline property relationship was explained by structural analysis of molecules using DFT calculations. Considering the inherent photoluminescence nature of the chalcone moiety, a preliminary study was carried out on a selected compound to reveal its fluorescence property. Conclusion: Our study brings about an important structure-liquid crystalline property relationship in a relatively unexplored class of bis-chalcone liquid crystals.

Chalcogenide Glass-Capped Fiber-Optic Sensor for Real-Time Temperature Monitoring in Extreme Environments

We demonstrate a novel chalcogenide glass (ChG)-capped optical fiber temperature sensor capable of operating within harsh environment. The sensor architecture utilizes the heat-induced phase change (amorphous-to-crystalline) property of ChGs, which rapidly (80–100 ns) changes the optical properties of the material. The sensor response to temperature variation around the phase change of the ChG cap at the tip of the fiber provides abrupt changes in the reflected power intensity. This temperature is indicative of the temperature at the sensing node. We present the sensing performance of six different compositions of ChGs and a method to interpret the temperature profile between 440 °C and 600 °C in real-time using an array structure. The unique radiation-hardness property of ChGs makes the devices compatible with high-temperature and high-radiation environments, such as monitoring the cladding temperature of Light Water (LWR) or Sodium-cooled Fast (SFR) reactors.

Recent advances in surface/interface engineering of noble-metal free catalysts for energy conversion reactions

Recent advances in characterization techniques and surface modification strategies of energy conversion catalysts are reviewed, with an emphasis on surface defect engineering, surface crystalline property modulation, surface structure tailoring and heterointerface construction.

La3+/Sr2+ Dual-Substituted Hydroxyapatite Nanoparticles as Bone Substitutes: Synthesis, Characterization, In Vitro Bioactivity and Cytocompatibility

The present study aims to synthesize biocompatible and bioactive lanthanum (La3+)/strontium (Sr2+) dual ion doped hydroxyapatite (HA) nanomaterials by sol–gel method. The discrete substitution of La3+ and Sr2+ in pure HA enhances the osteoconductivity. The co-substitution of various La3+ concentrations (0.03, 0.06 and 0.1 M) regulates the physical and In Vitro properties. The study also investigates the effect of La3+/Sr2+ substituents on the crystalline property, microstructure, photoluminescence and In Vitro bioactivity of HA samples. La3+/Sr2+ co-substitution decreases the crystallite size of HA without any significant distortion of the crystal structure. In addition, the dual ions doping influences nanoparticles morphology by reducing the particle size from 75 to 20 nm. The In Vitro bioactivity tests for the La3+/Sr2+ co-substituted HA confirm the osteoconductive boneapatite generating capacity. Bactericidal tests against Staphylococcus aureus and Pseudomonas aeruginosa stains show better resistivity of La3+/Sr2+-HA samples. To authenticate the biocompatibility and antimicrobial activity of the synthesized La3+/Sr2+ dual doped HA nanoparticles for bone implant applications, different tests like cell viability and toxicity were conducted using human lung A549 cells.

Synthesis and Structural Characterization of Some Lanthanide(III) Nitrate Complexes with a Mesogenic Schiff-Base, N,N’-di-4-(4’-heptadecyloxybenzoate) salicylidene-1,3-diaminopropane Derived from 2,4- dihydroxybenzaldehyde

Complexes of La(III), Pr(III), Nd(III), Sm(III), Gd(III) and Dy(III) with the Schiff-base, N,N′-di-4-(4’-heptadecyloxybenzoate)salicylidene-1,3-diaminopropane, (abbreviated as H2L) have been synthesized and characterized on the basis of elemental analyses, molar conductance, magnetic, electronic, infrared, 1H and 13C NMR spectral techniques. The nephelauxetic ratio (β), the bonding parameter (b1/2), Sinha’s parameter (%δ) and angular overlap parameter (η) have been calculated from the electronic spectra of Pr(III), Nd(III), Sm(III) and Dy(III) complexes. Infrared and NMR spectral data imply a bi-dentate bonding of the Schiff-base in its zwitterionic form (as LH2) to the Ln(III) ions through two phenolate oxygens, rendering the overall geometry around Ln(III) to distorted square antiprism. Polarized optical microscopy (POM) and differential scanning calorimetry (DSC) shows the liquid crystalline property of the ligand with a nematic (N) mesophase. Among the metal complexes, only that of the Gd(III) exhibits smectic B (SmB) and nematic (N) phases.