Biosynthesis of gold and silver nanoparticles by natural precursor clove and their functionalization with amine group

We report a simple and cost effective way for synthesis of metallic nanoparticles (Au and Ag) using natural precursor clove. Au and Ag nanoparticles have been synthesized by reducing the aqueous solution of AuCl₄ and AgNO₃ with clove extract. One interesting aspect here is that reduction time is quite small (few minutes instead of hours as compared to other natural precursors). We synthesized gold and silver nanoparticles of different shape and size by varying the ratio of AuCl₄ and AgNO₃ with respect to clove extract, where the dominant component is eugenol. The evolution of Au and Ag nanoparticles from the reduction of different ratios of AuCl₄ and AgNO₃ with optimised concentration of the clove extract has been evaluated through monitoring of surface plasmon behaviour as a function of time. The reduction of AuCl₄ and AgNO₃ by eugenol is because of the inductive effect of methoxy and allyl groups which are present at ortho and para positions of proton releasing –OH group as two electrons are released from one molecule of eugenol. This is followed by the formation of resonating structure of the anionic form of eugenol. The presence of methoxy and allyl groups has been confirmed by FTIR. To the best of our knowledge, use of clove as reducing agent, the consequent very short time (minutes instead of hours and without any scavenger) and the elucidation of mechanism of reduction based on FTIR analysis has not been attempted earlier.     

Experimental Investigations on Highly Conducting Solid Bio-Polymer Electrolytes Based on Latex of Calotropis gigantea Plant

The study has prepared highly conducting polymer electrolyte films using solution cast technique with poly(vinylidene fluoride-co-hexafluoropropylene) PVDF-HFP, mixture of ethylene carbonate (EC), and propylene carbonate (PC) as plasticizer and latex of Calotropis gigantea (CGL) as an ionic source. In this study, four films are prepared using PVDF-HFP:CGL in ratio 1:1 with the increasing concentration of EC+PC as 1, 2, 3, and 4 M named as 1:1:1, 1:1:2, 1:1:3, 1:1:4. The prepared polymer electrolyte is examined by polarized optical microscopy (POM), elemental dispersive X-ray technique (EDX), and complex impedance spectroscopy. EDX and POM are studied for the surface morphology of all prepared samples and to investigate the porous nature of films. The enhancement in ionic conductivity occurs due to CGL and increasing amount of EC-PC. Conductivity of highest composition (1:1:4) polymer electrolyte film is found to be ≈10⁻³ S cm⁻¹. The optimized polymer electrolyte film is considered as a promising candidate for application in supercapacitors.     

Quantitative determination of macroelement and microelement content of fresh and processed bamboo shoots by wavelength dispersive X-ray fluorescence spectrometry

Bamboo shoots are considered as healthy and nutritional food as they supply proteins, dietary fiber, phenols, phytosterols, vitamins, and minerals in considerable quantities and capture a novel place in the spectrum of plant foods. Besides nutrients and bioactive compounds, shoots also contain antinutrient (cyanogen) that needs to be removed by adequate processing prior to consumption. This study was undertaken to investigate the effects of fermentation, brine preservation, and boiling on levels of mineral elements in shoots of Dendrocalamus hamiltonii using wavelength dispersive X-ray fluorescence (WD-XRF) spectrometry. WD-XRF spectrometry is a method that causes the least destruction to the raw plant material as no harsh chemicals are used and gives the most accurate results. Fermentation process resulted in significant increase in the levels of Rb (9%), S (11%), Mg (12%), Zn (46%), Ca (56%), and Fe (87%); however, Na (18.79 g/100 g, dry weight), Cl (24.73 g/100 g, dry weight), and Br (20.0 mg/100 g, dry weight) content increased drastically after brine preservation. Boiling increased the levels of Fe by 139% but did not affect the Rb (20.0 mg/100 g, dry weight) and Zn content (10.2 mg/100 g, dry weight) of the shoots. In general, fermentation, which led to the lowest loss of mineral elements, appears the best method in enhancement and retention of the mineral content in bamboo shoots and holds the prospect at industrial and society levels.     

Quantum dynamics of h(2)(+) in intense laser fields on time-dependent potential energy surfaces

We have exploited the fully time-dependent Born-Oppenheimer approximation to develop time-dependent potential energy surfaces for the lowest two states of H(2)(+) in the presence of intense, time-varying, few-cycle laser fields of 2-8 fs duration. Quantum dynamics are explored on these field-dressed, time-dependent potentials. Our results show that the potential well in the lowest-energy state of H(2)(+) (i) collapses as the laser pulse reaches its peak amplitude and (ii) regains its form on the trailing edge of the pulse, and (iii) the trapped nuclear wavepacket has a higher probability of leaking out from the well in the case of longer laser pulses. The carrier envelope phase is found to have negligible effect on the nuclear dynamics.     

Explicit determination of certain minimal constabelian codes

Constabelian codes can be viewed as ideals in twisted group algebras over finite fields. In this paper we study decomposition of semisimple twisted group algebras of finite abelian groups and prove results regarding complete determination of a full set of primitive orthogonal idempotents in such algebras. We also explicitly determine complete sets of primitive orthogonal idempotents of twisted group algebras of finite cyclic and abelian p-groups. We also describe methods of determining complete set of primitive idempotents of abelian groups whose orders are divisible by more than one prime and give concrete (numerical) examples of minimal constabelian codes, illustrating the above mentioned results.     

The role of hydrogen bonding in pseudo-macrocyclic ring formation in 2,6-dimethyl-1,3,5,7-cyclooctatetraene 1,3,5,7-tetracarboxylic acid monohydrate

2,6-Dimethyl-1,3,5,7-cyclooctatetraene-1,3,5,7-tetracarboxylic acid 3, C₁₄H₁₄O₉, was prepared by thermolysis of the corresponding semibullvalene and characterized by spectroscopic and single-crystal X-ray diffraction studies. The monohydrate of 3 crystallizes in the tetrahedral space group P-4n2, a = 11.0924(3) Å, c = 12.6799(5) Å, V = 1560.15(9) ų, Z = 4. The cyclooctatetraene ring adopts a tub-shaped conformation with a crystallograpically imposed twofold rotational symmetry, and is composed of localized C=C double bonds in the 1,3,5, and 7 positions with an average interatomic distance of 1.327 (5) Å and C–C single bonds with an average interatomic distance of 1.489(5) Å. The average C=C–C angle in the ring is 122.6(3)°. Each symmetry generated eight-membered ring contains four carboxyl groups, two of which are coplanar with the methyl groups across the C=C ring atoms. However, across the C–C bonds the carboxyl groups and the methyl groups show a torsion angle of 64.3(4)°. The presence of a water molecule in the crystal lattice generates a three-dimensional network of close hydrogen bondings between water and the carboxyl groups of multiple rings. This creates a network of orthogonal 10-membered rings between the 8-membered rings. Two given cyclooctatetraene rings are intermolecularly hydrogen bonded not only directly through their carboxyl groups but also via a bridging water molecule. This effect is rare in polycarboxylic acids and their monohydrates which bond only with water or among themselves.