Analysis and Synthesis of Reverberation for Parametric Stereo Audio

We propose a parametric stereo coding analysis and synthesis directly in the MDCT domain using an analysis by synthesis parameter estimation. The stereo signal is represented by an equalized sum signal and spatialization parameters. Equalized sum signal and the spatialization parameters are obtained by sub-band analysis in the MDCT domain. The de-correlated signal required for the stereo synthesis is also generated in the MDCT domain. Subjective evaluation test using MUSHRA shows that the synthesized stereo signal is perceptually satisfactory and comparable to the state of the art parametric coders.

Enantiospecific synthesis of the ABC and ABD ring systems of the marine diterpenes aberraranes

Enantiospecific synthesis of the ABC and ABD ring systems present in the marine diterpenes aberraranes, starting from the readily available (S)-campholenaldehyde, has been accomplished. (C) 2011 Elsevier Ltd. All rights reserved.

Explorations en route to synthesis of tashironins: singlet oxygen cycloaddition to 1,3-cyclopentadienes embedded within allo-cedrane framework

In an approach directed toward a tashironin based complex natural product, efficacy of the singlet oxygen mediated [4+2]-cycloaddition to a tetracyclic cyclopentadiene has been evaluated to install the key cis-1,4-dihydroxy functionality. (C) 2011 Elsevier Ltd. All rights reserved.

Total synthesis of panaxytriol and panaxydiol

The enantioselective total synthesis of the diyne containing natural products panaxytriol and (3S,10R)-panaxydiol from L-tartaric acid is reported. Key steps in the synthesis include the elaboration of a gamma-hydroxy amide derived from tartaric acid to the required alkyne and the formation of the desired diyne unit by a Cadiot-Chodkiewicz coupling. (C) 2011 Elsevier Ltd. All rights reserved.

An Empirical Study of Synthesis of Multiple State Devices by Engineering Designers

Automated synthesis of mechanical designs is an important step towards the development of an intelligent CAD system. Research into methods for supporting conceptual design using automated synthesis has attracted much attention in the past decades. The research work presented here is based on an empirical study of the process of synthesis of multiple state mechanical devices. As a background to the work, the paper explores concepts of what mechanical device, state, single state and multiple state are, and in the context of the above observational studies, attempts to identify the outstanding issues for supporting multiple state synthesis of mechanical devices.

Efficient synthesis of carbonyl compounds: oxidation of azides and alcohols catalyzed by vanadium pentoxide in water using tert-butylhydroperoxide

Catalytic amount of vanadium reagent with tert-butylhydroperoxide as the oxidant was found to be an excellent oxidizing agent in aqueous medium. Vanadium pentoxide with aq tert-butylhydroperoxide readily oxidizes primary benzylic azides to the corresponding acids and secondary benzylic azides to the corresponding ketones in excellent yields. Further, vanadium pentoxide and aq tert-butylhydroperoxide combination turned out to be an effective catalyst for the oxidation of alcohols. Using vanadium pentoxide and aq tert-butylhydroperoxide primary alcohols were oxidized to the corresponding acids, whereas secondary alcohols underwent a smooth transformation to furnish corresponding ketones in excellent yields. All the oxidations are performed in water. (C) 2011 Elsevier Ltd. All rights reserved.

Hydrothermal synthesis of CdTe QDs: Their luminescence quenching in the presence of bio-molecules and observation of bistable memory effect in CdTe QD/PEDOT:PSS heterostructure

We report one-pot hydrothermal synthesis of nearly mono-disperse 3-mercaptopropionic acid capped water-soluble cadmium telluride (CdTe) quantum dots (QDs) using an air stable Te source. The optical and electrical characteristics were also studied here. It was shown that the hydrothermal synthesis could be tuned to synthesize nano structures of uniform size close to nanometers. The emissions of the CdTe QDs thus synthesized were in the range of 500-700 nm by varying the duration of synthesis. The full width at half maximum (FWHM) of the emission peaks is relatively narrow (40-90 nm), which indicates a nearly uniform distribution of QD size. The structural and optical properties of the QDs were characterized by transmission electron microscopy (TEM), photoluminescence (PL) and Ultraviolet-visible (UV-Vis) spectroscopy. The photoluminescence quenching of CdTe QDs in the presence of L-cysteine and DNA confirms its biocompatibility and its utility for biosensing applications. The room temperature current-voltage characteristics of QD film on ITO coated glass substrate show an electrically induced switching between states with high and low conductivities. The phenomenon is explained on the basis of charge confinement in quantum dots. (C) 2011 Elsevier B.V. All rights reserved.

Total synthesis of (-)-ent-pachastrissamine (ent-Jaspine B)

The total synthesis of the enantiomer of the tetrahydrofuran containing natural product Jaspine B is reported. The key reactions in the synthesis include formation of the tetrahydrofuran unit by an acid mediated Williamson etherification and a subsequent elaboration with an olefin cross metathesis reaction. (C) 2011 Elsevier Ltd. All rights reserved.

New Insights into Selective Heterogeneous Nucleation of Metal Nanoparticles on Oxides by Microwave-Assisted Reduction: Rapid Synthesis of High-Activity Supported Catalysts

Microwave-based methods are widely employed to synthesize metal nanoparticles on various substrates. However, the detailed mechanism of formation of such hybrids has not been addressed. In this paper, we describe the thermodynamic and kinetic aspects of reduction of metal salts by ethylene glycol under microwave heating conditions. On the basis of this analysis, we identify the temperatures above which the reduction of the metal salt is thermodynamically favorable and temperatures above which the rates of homogeneous nucleation of the metal and the heterogeneous nucleation of the metal on supports are favored. We delineate different conditions which favor the heterogeneous nucleation of the metal on the supports over homogeneous nucleation in the solvent medium based on the dielectric loss parameters of the solvent and the support and the metal/solvent and metal/support interfacial energies. Contrary to current understanding, we show that metal particles can be selectively formed on the substrate even under situations where the temperature of the substrate Is lower than that of the surrounding medium. The catalytic activity of the Pt/CeO(2) and Pt/TiO(2) hybrids synthesized by this method for H(2) combustion reaction shows that complete conversion is achieved at temperatures as low as 100 degrees C with Pt-CeO(2) catalyst and at 50 degrees C with Pt-TiO(2) catalyst. Our method thus opens up possibilities for rational synthesis of high-activity supported catalysts using a fast microwave-based reduction method.

Existing and emerging strategies for the synthesis of nanoscale heterostructures

Development of new multifunctional nanostructures relies on the ability to make new materials at the nanoscale with control over size, shape and composition. While this control is extremely important to tune several properties, an alternative strategy is to create active interfaces between two or more nanostructures to form nanoscale heterostructures. In these heterostructures, the interfaces play a key role in stabilizing and enhancing the efficiency of the individual components for various applications. In this article, we discuss synthesis methods of different types of nanoscale heterostructures and the role of interfaces in various applications. We present the current state-of-the-art in designing heterostructures and possible upcoming synthetic strategies with their advantages and disadvantages. We present how such heterostructures are highly efficient for catalytic, photovoltaic and nanoelectronic applications drawing several examples from our own studies and from the literature.

An Enantiospecific Approach to Tetraquinane Diterpenes Crinipellins: Synthesis of Norcrinipellins

An enantiospecific approach to the synthesis of tetraquinane diterpene crinipellins is described. The cyclopentane ring in campholenaldehyde was identified as the B ring. Two rhodium carbenoid CH insertion reactions for the construction of A and C rings and an intramolecular Michael addition reaction for the D ring of crinipellins were employed as key strategies for the enantiospecific synthesis of norcrinipellins.

An Enantiospecific Approach to Irregular Ligusticum grayi Sesquiterpenes: Synthesis of cis-Preisothapsa-2,8(12)-diene

Enantiospecific syntheses of 1-epi- (or cis-)-preisothapsa-2,8(12)-diene and 1-epi- and 1,8-diepipreisothapsa-2-en-12-ols, starting from the readily available monoterpene (R)-carvone, have been accomplished.

Enantiospecific synthesis of angular triquinanes

The enantiospecific synthesis of angular triquinanes has been developed starting from the readily available (S)-campholenaldehyde. Two alternate strategies have been used, one employing a Johnson's orthoester Claisen rearrangement followed by an intramolecular cyclopropanation and regioselective cyclopropane ring cleavage, and a second one based on a RCM reaction. (C) 2011 Elsevier Ltd. All rights reserved.