A New Type of Glucose Fermentation by Clostridium thermoaceticum
The thermophilic fermentation of cellulosic material is generally regarded -as a result of the combined action of several species of bacteria, some of which attack the cellulose and others the sugars formed from the breakdown of the cellulose. Much effort has been spent on attempts to isolate the cellulose fermenters but very little attention has been paid to the associated sugar-fermenting organisms. Snieszko and Kimball (1933) isolated and described two types of such bacteria but gave no chemical data on the fermentation products formed. It, therefore, seemed desirable to make such a study.
THE IODOMETRIC DETERMINATION OF COPPER AND ITS USE IN SUGAR ANALYSIS II. METHODS FOR THE DETERMINATION OF REDUCING SUGARS IN BLOOD, URINE, MILK, AND OTHER SOLUTIONS
In the course of a comparative study of several methods for the determination of sugar in blood, the results of which will be recorded elsewhere, it became desirable to investigate the reaction betsveen copper sulfate and potassium iodide which is concerned in a number of methods for sugar determination (Bang (l), Maclean (2), Scales (3), Lehmann (4), Riegler (4), Peters (4), Kendall (5)). In certain of these methods (Bang, Maclean, Scales) the cuprous oxide formed by the oxidation of the sugar is dissolved in acid1 and reoxidized to cupric salt by a known amount of standard iodine-potassium iodide, the excess of iodine being then titrated with thiosulfate. The oxidation takes place in the presence of considerable excess of cupric salts which under the conditions does not appear to inhibit the oxidation, the latter going apparently to completion. Essentially the same reaction between cupric salts and potassium iodide is the basis of the well known method for the iodometric determination of copper introduced by De Haen in 1854, the details of which have been studied especially by Gooc’h and Heath (6) who give the earlier literature. But in this case cupric salt is reduced to cuprous iodide in the presence of an excess of potassium iodide, with the liberation of free iodine
Enhancement of surface properties on Low Density Polyethylene packaging films using various fluorination routes
Nowadays, packaging market deployment requires an important attention. Influence of treatment with molecular (F2) or atomic (Fradical dot) fluorine on properties of Low Density Polyethylene (LDPE) films was investigated. The films were treated using direct fluorination conditions with F2 or a specific reagent XeF2, which releases atomic fluorine Fradical dot. Changes of LDPE chemical composition were investigated by FTIR and solid state NMR. Surface morphology was studied by several microscopy techniques (SEM and AFM). Finally to further characterize film properties after treatments, surface energy measurements and electron paramagnetic resonance (EPR) analyses were also carried out. An upper fluorinated layer, which contains mainly high amount of single bondCF2single bond, was formed during the direct fluorination conditions (F2). For the process performed with XeF2, specific groups single bondCHFsingle bond were detected not only on the polymer surface but also in the bulk. The final CHF/CF2 ratio depended on the fluorination route. Treatment with Fradical dot (originated from XeF2 decomposition) resulted in single bondCHFsingle bond groups in bulk prevailing formation whereas F2 formed mainly single bondCF2single bond groups. Regardless to the reactive species, radicals (dangling bonds) appeared during the fluorination and reacted with oxygen during the exposition to air after the treatment. Such a process resulted in oxygenated polar groups formation and consequently in the surface energy increase.