Investigation of Moisture Sorption,Permeability, Cytotoxicity and Drug Release Behavior of Carrageenan/Poly Vinyl Alcohol Films

This work describes moisture sorption behavior and water vapor permeability of glutaraldehyde-crosslinked carrageenan/polyvinyl alcohol (Carr/PVA) films. The moisture uptake has been studied under various relative humidity (RH) and the data obtained has been interpreted in the terms of various isotherm models such as GAB, Oswin and Halsey models. The moisture permeability through the films has been characterized in the terms of various parameters like water vapor transmission rate (WVTR), permeance (P) and water vapor permeability (WVP). It was found that these parameters are greatly affected by the degree of crosslinking of the films. Finally, the model drug Gentamycin Sulphate was loaded in to the films and its release was monitored kinetically in the physiological buffer (PF) at 37°C. The films exhibited diffusion controlled release mechanism. The films are non-cytotoxic.     

On-Demand Release of Urea From a Cellulosic Hydrogel Using a Sprinkler Based Irrigation (SBI) Model

In this work, epichlorohydrin (Ech) crosslinked cellulose hydrogels have been prepared and loaded with urea (Ur) for controlled release as a fertilizer. A detailed study of swelling behavior of these hydrogels and their urea releasing capacity has been carried out under various experimental conditions. The dynamic swelling and release data has been applied on various kinetic models. Finally, using a novel Sprinkler Based Irrigation (SBI) model, a model plant has been irrigated with water in the presence of urea-loaded hydrogel. It was found that plants, irrigated in the presence of urea-loaded hydrogel exhibited a better growth as compared to the control plant sample.     

A UNIQUE SUPRAMOLECULAR STRUCTURE OF POLY [μ-OXO -BIS(1,1,2,3,4,5-HEXAHYDRO-1-NITRATOTELLUROPHENE)] [(C4H8TENO3)2O]N WITH—0-TE-0-TE-0—CROSS LINKED CHAINS

Abstract

Poly [μ-oxo bis(1,1,2,3,4.5-hexahydro- 1-nitratotellurophene)] 1, is prepared by the room temperature reaction of 1,1,2,3,4,5-hexahydro- 1.1 -diiodotellurophene with silver nitrate in deionised water. Crystals of 1 are monoclinic. space group CUc with a=13.930(2) Å, b =11.665(2) Å, c=10.0682(11) Å, β=116.264(8)^O and Z=A. The monomeric unit of the title compound is centrosymmetric, with an angular TeOTe skeleton containing bridging O atom at the centre of symmetry. These monomeric units are linked together through —O-Te-O-Te-O—cross linked chains and the nitrate groups are asymmetrically bidentate with a primary Te-ONO₂ and a secondary Te—O semibonding interaction. Each nitrate group further participates in another Te–O semibonding interaction forming another asymmetric Te(NO₃)₂Te bridge. The structural characteristics of 1 are compared with related complexes.     

Synthesis and spectroscopic analysis of a stereoisomer library of the phytophthora mating hormone α1 and derived bis-Mosher esters

Fluorous mixture synthesis provided all eight diastereomers of the phytophthora hormone α1 with the R configuration at C11 as individual samples after demixing and detagging. The library of all possible bis-Mosher esters (16) was then made by esterification. Complete sets of (1)H, (13)C, and (for the Mosher esters) (19)F NMR spectra were recorded, assigned, and compared with each other and with published spectra. Not all of the spectra are unique, and the (1)H NMR spectra of the Mosher esters provided the most information. The previous assignment of the natural sample as an "all-R" stereoisomer mixed with its 3S-epimer was confirmed.     

Temperature-Gradient-Directed NMR Monitoring of a [3 + 3]-Cyclocondensation Reaction Between Alkynone and Ethyl 2-Amino-1H-indole-3-carboxylate Toward the Synthesis of Pyrimido[1,2-a]indole Catalyzed by Cs2CO3

We describe a NMR strategy to resolve temperature-gradient-monitored real-time chemical reaction involving a [3 + 3]-cyclocondensation reaction between alkynone and ethyl 2-amino-1H-indole-3-carboxylate toward the synthesis of pyrimido[1,2-a]indole catalyzed by Cs₂CO₃. The in situ NMR study clearly indicates that the reactant undergoes [3 + 3]-cyclocondensation reaction through a concerted mechanism, resulting in the product formation. The detailed NMR spectroscopic data led to the optimization of the reaction conditions and quantitative analysis of the product accurately and efficiently.

Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental file.     

The Moduli Space of Flat Connections on Oriented Surfaces with Boundary

A 2-form is constructed on the space of connections on a principal bundle over an oriented surface with boundary. This induces a symplectic structure for the moduli space of flat connections with boundary holonomies lying in prescribed conjugacy classes. The Yang-Mills quantum field measure is described for this situation. This measure converges to the normalized symplectic volume measure in the “classical” limit.     

Some results involving Bessel function and Fox’s H-function of two variables

In this paper, we have presented two integrals and employed them to establish one Fourier Bessel expansion for Fox’s H-function of two variables.     

A Mathematical Construction of the Non-Abelian Chern-Simons Functional Integral

We construct rigorously an infinite dimensional distribution which corresponds to the Chern-Simons (CS) functional integral associated with a principal fiber bundle over R ³ with structure group a compact connected Lie group. We determine the ‘moments’ of the CS distribution and show that these coincide with those used in informal studies of the CS integral. A locality property of the CS distribution is proven. The complexified theory of Fr?hlich and King is also discussed within our framework. Received: 2 April 1996 / Accepted: 15 August 1996