One pot synthesis of polymer protected gold nanoparticles and nanoprisms in glycerol

Uniform and stable polymer protected spherical gold nanoparticles were synthesized using glycerol as reducing agent. Further it was observed that the morphology of the particles varied from spherical to triangular prismatic gold nanoparticles when the reaction was changed from normal mode of reflux condition to microwave mode (MW) of heating. Further a brief mechanism relating the formation of prisms with the orientation of polymer and nucleation period has been discussed. Formation of triangular prismatic and spherical gold nanoparticles were characterised using UV–vis spectroscopy, transmission electron microscopy (TEM) and X-ray diffraction (XRD) analysis.     

Profiling bioactive flavonoids and carotenoids in select south Indian spices and nuts

Abstract

The objective of this study was to examine the bioactive flavonoids and carotenoids concentration in fifteen south Indian spice and two tree nut species using high performance liquid chromatography (HPLC). Among four flavonoids, catechin concentration was the highest in all spices and nuts and ranged between 97.1 and 1745.4 µg g^?1. Quercetin concentration was the greatest in cinnamon, followed by garlic and cumin and ranged from 0.4 to 65 µg g^?1 in other spices and nuts. Lutein concentration ranged from 0.1 to 102.8 µg g^?1. Of the spices and nuts studied, β-carotene concentration was highest in coriander leaves (74.7 µg g^?1), followed by red pepper (12.5 µg g^?1) and curry leaves (8.5 µg g^?1). This research shows that consumption of south Indian spices and nuts could substantially benefit consumers living in regions experiencing Vitamin A and other micronutrient deficiencies.     

Reversal of stability on metalation of pentagonal-bipyramidal (1-MB6H7(2-) 1-M-2-CB5H7(1-) and 1-M-2,4-C2B4H7) and Icosahedral (1-MB11H12(2-) 1-M-2-CB10H12(1-) and 1-M-2,4-C2B9H12) boranes (M = Al, Ga, In, and Tl): energetics of condensation and relationship to binuclear metallocenes

The usual assumption of the extra stability of icosahedral boranes (2) over pentagonal-bipyramidal boranes (1) is reversed by substitution of a vertex by a group 13 metal. This preference is a result of the geometrical requirements for optimum overlap between the five-membered face of the ligand and the metal fragment. Isodesmic equations calculated at the B3LYP/LANL2DZ level indicate that the extra stability of 1-M-2,4-C(2)B(4)H(7) varies from 14.44 kcal/mol (M = Al) to 15.30 kcal/mol (M = Tl). Similarly, M(2,4-C(2)B(4)H(6))(2)(1-) is more stable than M(2,4-C(2)B(9)H(11))(2)(1-) by 9.26 kcal/mol (M = Al) and by 6.75 kcal/mol (M = Tl). The preference for (MC(2)B(4)H(6))(2) over (MC(2)B(9)H(11))(2) at the same level is 30.54 kcal/mol (M = Al), 33.16 kcal/ mol (M = Ga) and 37.77 kcal/mol (M = In). The metal-metal bonding here is comparable to those in CpZn-ZnCp and H(2)M-MH(2) (M= Al, Ga, and In).     

Level structures of 95,97Mo — A comparative study

High-spin states of ^95,97Mo (Z=42, N=53,55) nuclei have been investigated through ⁸²Se(¹⁸O, xn) reaction at Eb=60 MeV. The level scheme in ⁹⁵Mo has been observed upto ≏ 10 MeV in the present experiment. The level structure shows mainly single particle character. In ⁹⁷Mo, the ground state level sequence has been extended to ≏ 4.5 MeV while the previous information had been up to 2.4 MeV. A negative parity band built on 1437 keV (11/2⁻) excited state has been extended to 5.5 MeV. The structure seems to show a coexistence of single particle and collective modes of excitation. Properties of both the nuclei have been compared with shell model calculations using OXBASH.     

High spin rotational bands in 65Zn

The nucleus ₃₀ ⁶⁵ Zn was studied using the ⁵²Cr(¹⁶O, 2pn)⁶⁵Zn reaction at a beam energy of 65 MeV. The level scheme is extended up to an excitation energy of 10.57 MeV for spin-parity (41/2?) with several newly observed transitions placed in it.     

Synthesis of gold and platinum nanoparticles using tetraaniline as reducing and phase transfer agent—A brief study and their role in the electrocatalytic oxidation of glucose

A one-pot synthesis of Au and Pt nanoparticles by the spontaneous reduction of chloroaurate and chloroplatinate ions using tetraaniline molecules has been elucidated. The importance of this work is that tetraaniline acts as a multifunctional molecule that accomplishes the complexation of aqueous chloroaurate and chloroplatinate ions by phase transferring them to organic medium and their subsequent reduction to yield Au and Pt nanoparticles in organic phase. The metal reduction is followed by polymerization of the amine to yield polyaniline, which subsequently caps the Au and Pt nanoparticles. Various analytical techniques have been used for probing the process of reduction of auric and platinic metal precursors like UV-vis, X-ray diffractogram (XRD) and transmission electron micrographic (TEM) analysis. Such prepared nanoparticles are utilized for the fabrication of novel modified electrodes towards the electrocatalytic oxidation of glucose.     

Beneficial effect of boron on the structural and magnetostrictive behavior of Fe77Ga23 alloy

Alloys of Fe₇₇Ga₂₃B_x (x=0, 0.025, 0.050, 0.075 and 0.1) were heat treated at 1000 °C/10 h and characterized for microstructural features and magnetostriction. The study indicates that the parent alloy consists of three phases viz. A2 as the major phase and L1₂ and DO₃ as minor phases. However, the volume fraction of L1₂ and DO₃ decreases with B addition and as a result magnetostriction improves. The decrease in volume fraction of these phases is attributed to B-segregation to the grain boundary, which seems to prevent the formation of these phases. The alloy with x=0.1, however, exhibits an additional Fe₂B phase and consequently its presence leads to the re-emergence of the DO₃ phase, affecting the magnetostriction.     

Photogeneration of reactive oxygen species and photoinduced plasmid DNA cleavage by novel synthetic chalcones

This paper describes the synthesis and photodynamic properties of six different chalcone derivatives. Using N,N-dimethyl-4-nitrosoaniline (RNO) bleaching assay, the singlet oxygen generating efficiencies of these chalcones are determined relative to rose bengal (RB). Superoxide dismutase (SOD) inhibitable cytochrome c reduction assay and electron magnetic resonance (EMR) spin trapping techniques are used to determine the superoxide anion radical (O?·?) yield upon photoirradiation. Photoinduced DNA scission studies show that O?·? is involved in the DNA strand break. In addition, antimicrobial activity of these chalcones is also investigated. Structure activity relationship accounts for the difference in the photogeneration of reactive oxygen species (ROS) by these sensitizers. Presence of electron releasing -OCH? groups enhances the photogeneration of ROS. Cyclic voltammetry studies indicate a correlation between enzymatic O?·? generation efficiency and redox potential of chalcones. Both O?·? (Type I) and 1O? (Type II) paths are involved in the photosensitization of chalcones. The LUMO energies obtained by molecular modeling correlate with the one-electron reduction potentials.     

Treatment of petroleum refinery wastewater by ultrasound-dispersed nanoscale zero-valent iron particles

Petroleum refineries release wastewater, which is rich in organic pollutants and cannot be treated easily. This study presents the treatment of petroleum refinery wastewater using nanoscale zero valent iron (NZVI) in the presence of ultrasonication. NZVI characteristics were analyzed using SEM and XRD. The influence of NZVI dosage and initial pH on % chemical oxygen demand (COD) reduction was studied. From the results, it can be inferred that a dosage of 0.15 g/l and an initial pH are optimum for the effective degradation of effluents. The degradation data were found to follow first order kinetics. The results indicate that using NZVI in combination with ultrasonication is an efficient method for the treatment of petroleum refinery wastewater.