Derivatives of p-aminobenzoic acid and their action on the growth of bacteria
SummaryVarious derivatives of P.A.B. obtained by introduction of substituents in the benzene-nucleus have been examined for their action on the growth ofAerobacter aerogenes in a simple synthetic medium and ofDiplococcus pneumoniae in ascites-broth without peptone.The following results have been obtained:1.The 2-amino, 3-amino, 3-chloro, 3-bromo, 2-methyl, 3-methyl, and 2.3-dimethyl derivatives of P.A.B., and also 2-sulfanilamido-4-aminobenzoic acid have sulfonamide activity.2.The 2-hydroxy, 2-fluoro, and 2-nitro derivatives have an antisulfonamide activity similar to the activity of P.A.B., although weaker.3.The 3-hydroxy, 2-chloro, and 2-bromo derivatives show sulfonamide-activity in relatively high concentrations. In lower concentrations they act as anti-sulfonamides.4.The 3-nitro, 2.6-dimethyl, and 3.5-dimethyl derivatives, and methyl 2-acetamino-4-amino-benzoate are completely inactive. These results have been compared with those of other investigators and the causes of some contradictions have been elucidated.
Mechanism of Sulfonamide Action. III. Biological Action of Substituted p-Aminobenzoic Acids.∗
Summary The biological action of substituted p-aminobenzoic acids studied in this series of experiments is summarized in Table V. Substitutions on the ring of p-aminobenzoic acid resulted in compounds which were either inactive or had varying degrees of sulfonamide or antisulfonamide action. Although the compounds with sulfonamide action are relatively non-toxic, their value in systemic chemotherapy has not been demonstrated.
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.