pH-Abhängige Einflüsse apparativer Parameter auf den Diffusionsfluß durch Lipoidmembranen

pH Dependent Influences of Apparatus Parameters on the Flux of Diffusion Through Lipoid Membranes The pH dependence of the diffusion of salicylic acid through membranes containing dodecanol was investigated. The lower the pH, the more does the aqueous layer resist the flux of diffusion. For this reason, apparatus parameters that control the convection of the aqueous phase variously influence the diffusion rate at different pH values. The diffusion resistance of the aqueous layer can be calculated from experimental data.     

Komplexbildung zwischen 1-Methylbarbital und Dimethylacetamid

Complexation between 1-Methylbarbital and Dimethylacetamide The complexation between 1-methylbarbital and dimethylacetamide by hydrogen bond was investigated by means of the light absorption in the near infrared and by NMR-spectroscopy taking into account the self-association of 1-methylbarbital. An 1 : 1-complex is formed, its association constant and enthalpy were determined.     

Synthesen von Flavon-2′-carbonsäuren und Chromono-(2′,3′-3,4)-isocumarin-derivaten

Synthesis of Flavone-2′-carboxylic Acids and Chromonoisocoumarines When we tried to synthesize 1,2-bischromonylbenzene derivatives from phthalic acid and o-hydroxy-acetophenone derivatives by Baker-Venkataraman-rearrangement flavone-2′-carboxylic acid derivatives are obtained in one step. This is a simple way to get flavone-2′ carboxylic acids and chromonoisocoumarines.     

Treatment of malignant melanoma with dinitrochlorobenzene ointment

35 patients with malignant melanomas in different stages were treated with dinitrochlorobenzene according to Malek-Mansour in the last three years. Nine typical cases are demonstrated. The treatment is more effective when the tumor lies close to skin surface and has not yet spread. Distant metastases may react--but normally these metastases cannot be removed. Regarding effects and side effects of DNCB, the methods of treatment and the range of indications are described.     

A novel in vitro microbial-based model for studying caries formation--development and initial testing

We report on the development and the initial testing of a new microbial-based caries model. Specimens were fixed on a rotating mount within a reaction chamber hermetically surrounded by a sterilised glove box. A cariogenic environment was obtained by inoculation with Streptococcus mutans (ATCC 25175) combined with a continuously repeating supply of sucrose solution, trypticase soy broth and artificial saliva applied by dripping. Twenty-five caries-free upper premolars were used. The mesial parts of the occlusal fissures had been sealed with a resin-based fissure sealant (test group 1). To produce marginal gaps, the distal parts had been moistened with saliva before resin application (test group 2). Five teeth served as control and were exposed to all fluids under sterile conditions before being removed from the system after 7 days. Test specimens were infected with S. mutans and were incubated for another 14 days. No unintentional contamination occurred during the 3-week period of operation. Demineralizations were evaluated by using confocal laser scanning microscopy. Only the test specimens showed clearly visible signs of biofilm formation and caries-like lesions. The mean primary lesion depth did not differ significantly between test groups. Wall lesion depths and surface areas of demineralizations underneath the fissure sealants were significantly higher in test group 2. Thus, our model allows the simultaneous production of primary and secondary caries-like enamel lesions in a considerable number of specimens and facilitates the possibility to manipulate and transfer them without necessarily terminating the experiment, opening new possibilities for in vitro caries research.