Cellulose acetates from linters and sisal: correlation between synthesis conditions in DMAc/LiCl and product properties.

We report the acetylation of celluloses from sisal (untreated and alkali treated) and cotton linters (alkali treated), under homogeneous solution conditions, using DMAc/LiCl as solvent system. Our target was to evaluate the effects of cellulose dissolution and reactions conditions on the product properties. The products were characterized in terms of degree of substitution (DS) by 1H NMR, and molar weight distribution (MWD) by size exclusion chromatography.

[Influence of blockades with local anesthetics on the stimulation ability of a nerve by peripheral nerve stimulation. Results of a randomized study].

In the present study we examined the influence of local anesthetics on the ability to stimulate a nerve by means of peripheral nerve stimulation. In 35 patients either 5 ml saline (group 1, n=18) or local anesthetics (group 2, n=17) were injected close to the sciatic nerve in a randomized and double-blind manner. The current needed to stimulate the nerve was measured 30 s and 2 min after injection.

Studies on the homogeneous acetylation of cellulose in the novel solvent dimethyl sulfoxide/tetrabutylammonium fluoride trihydrate.

The novel solvent dimethyl sulfoxide (DMSO)/tetrabutylammonium fluoride trihydrate (TBAF . 3H(2)O) was studied for acetylation of linters cellulose. In order to control the degree of substitution (DS), acetylation of the macromolecule was carried out at different reaction time and temperature, molar ratio of reactants, as well as under variation of the concentration of TBAF .

[Vertical infraclavicular blockade of the brachial plexus (VIP). A modified method to verify the puncture point under consideration of the risk of pneumothorax].

Introduction: The vertical infraclavicular blockade of the brachial plexus (VIP) according to Kilka et al.is a technique which has gained more importance over the past years. This method distinguishes itself from other periclavicular techniques by a very low risk of pneumothorax (0.