Study of Magnetic and Electrical Properties of Poly(o-phenylenediamine)/Manganese Substituted ZnFe2O4 Nanocomposites

Journal of Inorganic and Organometallic Polymers and Materials - Different concentrations of ZnFe2O4 and manganese substituted ZnFe2O4 nanoparticles (10%, 20% and 30%) dispersed...     

Selenium dioxide reaction of substituted diphenacyl sulfides: generation of α -ketoacids

The attempted selenium dioxide oxidation of substituted diphenacyl sulfides in anticipation of further functionalization led to a series of α -ketoacids 3 via oxidation followed by C?S bond cleavage. Two minor products, 5 and 6, have also been isolated and a mechanistic pathway for the formation of 3, 5 and 6 has been proposed.     

Synthesis and characterization of aromatic/cycloaliphatic poly(amide‐ imide‐imide)s from bis(4‐amino‐ 3,5‐dimethylphenyl) cycloalkane derivatives

A series of novel aromatic diamines containing cycloaliphatic moieties was synthesized by the reaction of cycloalkanones like cyclohexanone and cycloheptanone with 2,6‐dimethylaniline. The tetrimide diacid was synthesized using the prepared diamine with 3,3′,4,4′‐benzophenonetetracarboxylic acid dianhydride/pyromellitic dianhydride and p‐aminobenzoic acid. The polymers were prepared by treating the tetrimide diacid with different aromatic diamines. The structures of the monomers and polymers were identified using elemental analysis and Fourier transform infrared, ¹H NMR and ¹³C NMR spectroscopy. The polymers show excellent solubility. The polymers are amorphous and have high optical transparency. They also show good thermal stability and their T_g value is found to be in the range 268–305 °C. Copyright © 2007 Society of Chemical Industry     

Mathematical modeling of thermoelectric generator driven by solar parabolic dish collector

This paper presents mathematical modeling of thermoelectric power generator driven by solar parabolic dish collector. The system is modeled by set of mathamatical equations from the first law of thermonadynamics for the subcompoents of solar parabolic dish collector and thermoelectric power generator. The model is solved analytically for the a set of operating and design parameters. Modeling results can be useful for further development of the system to study it economic viability.     

Synthesis,characterization and properties of photoresponsive polymers comprising photocrosslinkable pendant chalcone moieties

New methacrylate monomers, namely 4‐methacryloyloxyphenyl‐4′‐fluorostyryl ketone and 4‐methacryloyloxyphenyl‐4′‐ethylstyryl ketone comprising a free radical polymerizable group and a photocrosslinkable group, were synthesized by reacting the respective hydroxychalcones with methacryloyl chloride in the presence of triethylamine. The monomers were polymerized in the presence of ethyl methyl ketone (EMK) at 70 °C using benzoyl peroxide as the initiator. The chemical structures were characterized using various spectroscopic techniques: ultraviolet, Fourier transform infrared, ¹H NMR and ¹³C NMR. The thermal stability of the polymers was studied using thermogravimetric analysis in nitrogen atmosphere. Differential scanning calorimetry was used to determine the glass transition temperature of the homopolymers. Photocrosslinking of the synthesized homopolymers was investigated in solution. The two homopolymers were crosslinked within 10–15 min. After crosslinking, the homopolymers were insoluble in the same solvent. Copyright © 2006 Society of Chemical Industry     

Specific Modulation of Protein Activity by Using a Bioorthogonal Reaction

Unnatural amino acids with bioorthogonal reactive groups have the potential to provide a rapid and specific mechanism for covalently inhibiting a protein of interest. Here, we use mutagenesis to insert an unnatural amino acid containing an azide group (Z) into the target protein at positions such that a “click” reaction with an alkyne modulator (X) will alter the function of the protein. This bioorthogonally reactive pair can engender specificity of X for the Z‐containing protein, even if the target is otherwise identical to another protein, allowing for rapid target validation in living cells. We demonstrate our method using inhibition of the Escherichia coli enzyme aminoacyl transferase by both active‐site occlusion and allosteric mechanisms. We have termed this a “clickable magic bullet” strategy, and it should be generally applicable to studying the effects of protein inhibition, within the limits of unnatural amino acid mutagenesis.     

Synthesis and characterisation of organosoluble polyimides containing the anisyl moiety

A new type of diamine monomer containing the anisyl moiety was synthesized via a straight‐forward one‐step procedure. Anisaldehyde was reacted with 2,6‐dimethylaniline in the presence of dry HCl to attain bis(4‐amino‐3,5‐dimethylphenyl)anisylmethane. A series of organo‐soluble polyimides were prepared using the anisyl diamine and various aromatic dianhydrides via a two step method involving thermal imidization. All polyimides are soluble in strong polar solvents such as N‐methyl‐2‐pyrollidone, N,N‐Dimethylformamide, and N,N‐DimethylAcetamide. The polyimides show excellent thermal stability and good mechanical properties. The glass transition temperatures of the polyimides are in the range 265–294 °C. The tensile strengths are in the range 79–99 MPa and the temperatures at which 10 % weight loss occurs are in the range 460–496 °C. Copyright © 2004 Society of Chemical Industry     

Biopreservative technologies of food: an alternative to chemical preservation and recent developments

Food Science and Biotechnology - Despite centuries of developing strategies to prevent food-associated illnesses, food safety remains a significant concern, even with multiple technological...