Real-Time Monitoring of the Mechanical Properties of a Soy Protein and Rubber Polymer during its Production Using Transient Infrared Spectroscopy

Soy protein–based polymers offer promising performance properties, but their characteristics are sensitively dependent on production conditions, so on-line monitoring could help provide the needed control during production. Mid-infrared spectroscopy combined with partial least squares offer the needed analysis, but the opacity of many materials in the mid-infrared range limits its conventional application. Transient infrared spectroscopy is a method of acquiring mid-infrared spectra from moving streams in real time that avoids the opacity problem. We apply transient infrared spectroscopy to a polymer of soy protein and polyisoprene-graft-maleic anhydride–modified natural rubber during its compounding extrusion to measure tensile strength and Young's modulus.     

Design, synthesis and antiviral potential of 14-aryl/heteroaryl-14H-dibenzo[a,j]xanthenes using an efficient polymer-supported catalyst

Polyethyleneglycol bound sulfonic acid (PEG-OSO?H), a chlorosulphonic acid-modified polyethylene glycol was successfully used as an efficient and eco-friendly polymeric catalyst in the synthesis of 14-aryl/heteroaryl-14H-dibenzo[a,j]xanthenes obtained from the reaction of 2-naphthol and carbonyl compounds under solvent-free conditions with short reaction times and excellent yields. The biological properties of these synthesized title compounds revealed that compounds 3b, 3c, 3f and 3i showed highly significant anti-viral activity against tobacco mosaic virus.     

Optimization of size and shape of composite heat sinks with phase change materials

A composite heat sink is one in which a phase change material is interspersed with a high thermal conductivity base material to maximize the thermal performance of the device. Unlike constant area fins considered in literature, this work considers a repeating elemental composite heat sink (ECHS) with variable area fins. The base material is aluminium and the phase change material is n-Eicosane. An in house code was developed in MATLAB© to determine the time of operation for a vertical fins ECHS for a one dimensional approximation. This was followed by a two dimensional analysis of the problem using FLUENT 6.3. The effects of the shape of the interface surface on the time of operation and overall heat dissipated are determined and design modifications for the composite Heat Sinks based on the results obtained are suggested.     

4-Mercaptophenylacetic acid functionalized Mn2+-doped ZnS nanoparticles fluorescence quenching caused by the addition of Cu2+

This paper reports that 4-mercaptophenylacetic acid functionalized Mn²⁺-doped ZnS nanoparticles (4-MPAA-ZnS-Mn²⁺ NPs) as fluorescent probes for the detection of copper ions in solution. The fluorescence quenching was due to the aggregation of copper ions with 4-MPAA-ZnS-Mn²⁺ NPs. These aggregations were confirmed by using UV lamp, UV–visible spectroscopy and dynamic light scattering (DLS). These 4-MPAA-ZnS-Mn²⁺ NPs were applied as fluorescent probes to detect copper ions in aqueous solution.     

HPTLC Densitometric Quantification of Glycyrrhizin,Glycyrrhetinic Acid,Apigenin, Kaempferol and Quercetin from Glycyrrhiza glabra

Glycyrrhiza glabra Linn., commonly known as liquorice, is a reputed drug of Ayurveda. In the present work we developed and validated densitometric methods for quantification of glycyrrhizin, glycyrrhetinic acid, apigenin, kaempferol and quercetin using HPTLC. The developed methods were found to be precise and accurate. The amount of glycyrrhizin, glycyrrhetinic acid, and quercetin was found to be 1.070, 0.84 and 0.271% w/w, respectively. Apigenin and kaempferol were quantified in free (0.007 and 0.033% w/w) as well as bound (0.021 and 0.074% w/w) forms. This is the first report of simultaneous quantification of glycyrrhetinic acid and apigenin as well as kaempferol and quercetin from G. glabra. Furthermore, no TLC densitometric methods have been reported for the quantification of apigenin, kaempferol and quercetin from G. glabra.

     

HPTLC Densitometric Quantification of Glycyrrhizin, Glycyrrhetinic Acid, Apigenin, Kaempferol and Quercetin from Glycyrrhiza glabra

Glycyrrhiza glabra Linn., commonly known as liquorice, is a reputed drug of Ayurveda. In the present work we developed and validated densitometric methods for quantification of glycyrrhizin, glycyrrhetinic acid, apigenin, kaempferol and quercetin using HPTLC. The developed methods were found to be precise and accurate. The amount of glycyrrhizin, glycyrrhetinic acid, and quercetin was found to be 1.070, 0.84 and 0.271% w/w, respectively. Apigenin and kaempferol were quantified in free (0.007 and 0.033% w/w) as well as bound (0.021 and 0.074% w/w) forms. This is the first report of simultaneous quantification of glycyrrhetinic acid and apigenin as well as kaempferol and quercetin from G. glabra. Furthermore, no TLC densitometric methods have been reported for the quantification of apigenin, kaempferol and quercetin from G. glabra.     

Synthesis of polyamides and polyureas containing leucine–tyrosine linkages

Monomers with leucine–tyrosine linkages were synthesized using diphenyl phosphoryl azide as a coupling reagent. Leucyltyrosylpoly(propylene glycol) bis(2-aminopropyl ether) tyrosylleucine (monomer 1 ) has a longer spacer: poly(propylene glycol) bis(2-aminopropyl ether) (Jeffamine® D-400), and leucyltyrosyliminohexamethyleneiminotyrosylleucine (monomer 2 ) has a shorter spacer: hexamethylenediamine. Polyureas from monomers 1 and 2 with hexamethylene diisocyanate and methylenedi-p-phenyl diisocyanate were synthesized. Polyamide, polyesteramide from monomer 2 were synthesized. The characterization of these polymers using ¹H-NMR, ¹³C-NMR, solid-state ¹³C-NMR, IR, GPC, and also thermal analysis are presented. © 1997 John Wiley & Sons, Inc.