We describe a procedure for the determination of hydrochloric acid concentration in gastric juice by means of a conductometric titration of the 50-fold diluted sample with an aqueous ammonia solution. The conductometric method of endpoint indication leads to a definite location of the equivalence point in the titration of hydrochloric acid. The proposed method is simple and accurate and shows a...

Despite great public interest and desperate need, progress toward a viable human immunodeficiency virus (HIV) vaccine remains incredibly slow. Since Merck began its HIV vaccine research in 1985, the pharmaceutical company has yet to produce a vaccine capable of passing Phase II testing. Merck Laboratories President Peter S. Kim recently delivered a speech at Yale University that detailed his co...

H and C nuclear magnetic resonance (NMR) spectra were recorded at 400 MHz on a Bruker ARX-400 NMR spectrometer (Germany) with tetramethylsilane as internal standard. Column chromatography was performed using Merck (Germany) silica gel (230-400 mesh). Thin layer chromatography (TLC) was performed using Merck silica gel GF254, 0.25 mm thickness. For visualization, TLC plates were placed under aci...

This paper deals with the chemical treatments with selected organic compounds that have been applied to Miscanthus to upgrade it, for pulp production or fractionation purposes. Organosolv processes have demonstrated their effectiveness as fractionation treatments; therefore special emphasis is placed on these systems and, in particular, those making use of carboxylic acids. That is, Acetosolv p...

Professor Karl August Folkers (Figure 1), a biochemist from the United States, was the head of one of the two research groups, one in England and one in the United States. In 1948, the two groups independently and simultaneously reported the isolation of vitamin B12 [1,2]. Most of Folkers’ work was carried out while working at the Merck Company (later Merck Sharp & Dohme) from 1934 to 1963. His...