Contradictory evidence exists as to the acid necessary for producing optimum enamel etching on buccal tooth surfaces. The aims of this study were to (1) compare the etching abilities of four different acids; (2) identify the acid concentrations required for optimum etching; and (3) determine the concentration stability of phosphoric acid solutions. Crowns of caries-free molar teeth were pumiced...

In this research, gibbsite (GB) samples calcined at 200-1000°C (GB200-GB1000) were produced. These GBs were used to adsorb orthophosphoric, pyrophosphoric, and tripolyphosphoric acids from aqueous solutions. The properties (amounts of hydroxyl groups, specific surface areas, mean pore diameters, and solution pHs) of the GBs were investigated, and their adsorption capacities for phosphoric acids...

Glycerol is a by-product of biodiesel produced by transesterification and is contained in the glycerol phase together with many other materials such as soaps, remaining catalyst, water, and esters formed during the process. The content of glycerol is approximately 30-60 wt.%. In this paper, treatments of the glycerol phase to obtain glycerol with a purity of 86 wt.% (without distillation) and a...

Addition of Potassium cyanide to a mixture of Schiff base and lithium perchlorate afforded a-aminonitriles in high yields. Addition of potassium cyanide to a methanolic solution of Schiff base and phosphoric acid afforded a-aminonitriles. When the reaction mixture was refluxed it gave a-amino acids in high yields.

In a previous report (1) the isolation, toxicity and some chemical data concerning the lipopolysaccharide endotoxin of Neisseria gonorrhoeae was described. The present investigation includes the following: (a) an improved modification of lipopolysaccharide phosphoric acid ester preparation; (b) hydrolysis of lipopolysaccharide phosphoric acid ester and removal of fatty acids; (c) separation of ...