Green biosynthesis of gold nanoparticles using Croton sparsiflorus leaves extract and evaluation of UV protection,antibacterial and anticancer applications

Our study reports greener synthesis of gold nanoparticles (AuNPs) tethered to the extract of Croton sparsiflorus and in vitro evaluation of UV-protection, antibacterial and anticancer activities. Sophisticated instrumental analytical techniques such as UV–vis spectrophotometer, FT-IR, XRD, FE-SEM, and TEM were employed for the existence and confirmation of the nanoparticles. FT-IR and HPLC analysis were executed in the identification of the plausible functional groups implicated in the reduction of gold ions to AuNPs. UV protection property and antibacterial action of AuNPs-coated cotton fabric were also presented. Moreover, in vitro anticancer evaluation against HepG2 cell line was conducted by MTT assay for Croton sparsiflorus extract derived AuNPs in different concentrations (50 to 150 μg/ml). Thus, the results of this work revealed that greener synthesized AuNPs exhibited good therapeutic applications as UV-protection, antibacterial and anticancer agents.     

Concurrent genesis of color and electrical conductivity in leathers through in‐situ polymerization of aniline for smart product applications

We present a simple method to produce self‐colored and conducting leathers using in‐situ polymerization of aniline with ammonium persulfate as oxidant and hydrochloric acid as dopant. The structural and morphological features of treated leathers were examined using Fourier transformed infra‐red spectroscopy, X‐ray diffraction and scanning electron microscopic analyses. Results suggest the deposition of conducting emeraldine salt form of polyaniline on the leather substrate rather than other poorly conducting states. We also show that the treated leathers are bluish green through reflectance measurements thereby suggesting that the use of toxic and expensive dyes can be avoided for coloration process. Further, we demonstrate that a maximum electrical conductivity of 0.15 S/cm is obtained for the leather treated with optimal experimental conditions, which aids its application to operate touch‐screen devices. Copyright © 2015 John Wiley & Sons, Ltd.     

Aldo‐X Bifunctional Building Blocks for the Synthesis of Heterocycles

Compounds containing oxygen, nitrogen, or sulfur atoms inside the rings are attracting much attention and interest due to their biological importance. In recent years, several methods for the synthesis of such molecules have been reported by using aldo‐X bifunctional building blocks (AXB3 s) as substrates; these are a wide class of organic molecules that contain at least two reactive sites, among them, one aldehyde, acetal, or semiacetal group was involved. Because of the multiple reactivities, AXB3 s are widely used in the one‐pot synthesis of biologically important heterocycles. This review summarizes the synthesis of important heterocycles by using AXB3 s as pivotal components in establishing multicomponent reactions, tandem reactions, and so forth. In many cases, the established reaction systems with AXB3 s were characterized by some green properties, such as easy access to the substrate, mild and environmentally benign conditions, and wide scope of the substrate.     

Progress and Prospects on the Fabrication of Graphene-Based Nanostructures for Energy Storage,Energy Conversion and Biomedical Applications

Graphene, a two-dimensional (2D) layered material has attracted much attention from the scientific community due to its exceptional electrical, thermal, mechanical, biological and optical properties. Hence, numerous applications utilizing graphene-based materials could be conceived in next-generation electronics, chemical and biological sensing, energy conversion and storage, and beyond. The interaction between graphene surfaces with other materials plays a vital role in influencing its properties than other bulk materials. In this review, we outline the recent progress in the production of graphene and related 2D materials, and their uses in energy conversion (solar cells, fuel cells), energy storage (batteries, supercapacitors) and biomedical applications.     

Li ion conduction in TiO2 filled polyvinylidenefluoride-co-hexafluoropropylene based novel nanocomposite polymer electrolyte membranes with LiDFOB

This paper describes, nanocomposite polymer electrolyte (NCPE) based on polyvinylidenefluoride-co-hexafluoropropylene (PVdF-HFP), which comprises the novel lithium difluoro(oxalato)borate (LiDFOB). Ehtylene carbonate (EC) and diethyl carbonate (DEC) mixture was used as gelling agent and nanoparticulate TiO₂ used as filler. The NCPE membranes were subjected to a.c. impedance, tensile strength, Raman studies, TG/DTA and morphological studies. 5 wt% TiO₂ comprising membranes exhibited enhanced conductivity of 0.56 mS cm⁻¹and the Young’s modulus was increased from 1.32 to 2.74 MPa. The structural change of α to β phase was confirmed by Raman studies. The thermal stability of the NCPE membrane is found to be 130 °C. Calculation of activation energy and synthesis of LiDFOB has also been presented.     

Chemical approach to the realization of electronic devices in epitaxial graphene

We have shown that nitrophenyl groups may be added to the surface of few‐layer epitaxial graphene (EG) by the formation of covalent carbon–carbon bonds thereby changing the electronic structure and transport properties of EG from near‐metallic to semiconducting. In the present Letter we discuss the opportunities afforded by such chemical processes to engineer device functionality in graphene by modification of the electronic properties without physical patterning.

     

Multiwalled Carbon Nanotubes: Adsorbent for Ruthenium from Aqueous Solution

Journal of Radioanalytical and Nuclear Chemistry - This paper describes the adsorption behavior of ruthenium on multi walled carbon nanotubes (MWCNTs) from aqueous solution. The adsorption behavior...     

Synthesis and Antimicrobial Evaluation of 1,4-Naphthoquinone Derivatives as Potential Antibacterial Agents

1,4-Naphthoquinones are an important class of compounds present in a number of natural products. In this study, a new series of 1,4-naphthoquinone derivatives were synthesized. All the synthesized compounds were tested for in vitro antimicrobial activity. In this present investigation, two Gram-positive and five Gram-negative bacterial strains and one pathogenic yeast strain were used to determine the antibacterial activity. Naphthoquinones tested for its antibacterial potencies, among seven of them displayed better antimicrobial activity against Staphylococcus aureus (S. aureus; 30–70 μg/mL). Some of the tested compounds showed moderate to low antimicrobial activity against Pseudomonas aeruginosa (P. aeruginosa) and Salmonella bongori (S. bongori; 70–150 μg/mL). In addition, most active compounds against S. aureus were evaluated for toxicity to human blood cells using a hemolysis assay. For better understanding, reactive oxygen species (ROS) generation, time-kill kinetic study, and apoptosis, necrosis responses were investigated for three representative compounds.     

Some ABO3 oxides with defect pyrochlore structure

Studies on the formation, structures and properties of the ternary oxides TlNbO₃, TlTaO₃ and BiVO_3+x occurring in A₂B₂O_7-y defect pyrochlore structure are reported. The reaction of Tl₂ CO₃ with Nb₂O₅/Ta₂O₅ initially leads to the formation of TlNbO_3+x [x ～ 0.3] and TlTaO_3+x [x ～ 0.4]. On further heating, the phases lose oxygen forming TlTaO₃ and TlNbO₃. The occurrence of ABO₃ oxides having Tl⁺, Pb²⁺ or Bi³⁺ as the A cation in defect pyrochlore structure in preference to the perovskite structure is attributed to the formation of a “trap-mediated” A-A bond through 6s² electrons.