Aliphatic amines, such as n-hexylamine (primary), di-n-hexylamine (secondary) and tri-n-hexylamine (tertiary amine), react with tetrabromophenolphthalein ethyl ester molecules (TBPEH) to form reddish or red-violet charge-transfer complexes (CT complexes) in 1,2-dichloroethane (DCE). The absorption maxima of the CT complexes with all primary amines occur at around 560 nm, with secondary amines a...

The determination of biogenic amines in alcoholic beverages is important to assess the potential risks associated with the consumption of high concentrations of these compounds. In addition, product storage conditions and the length of storage can cause the formation of biogenic amines that reduce product quality. We report a new method using cation-exchange chromatography with either suppresse...

Aliphatic amines were determined in sediments and sediment pore waters from several contrasting sites in Chesapeake Bay. The aliphatic amines diethylamine, set-butylamine, n-propylamine, and i-propylamine were detected in a limited number of pore-water samples at concentrations generally less than 0.6 /IM. The occurrence of these amines showed no obvious correlation to other sediment geochemica...

We examined the effects of weakly basic amines on the secretion and post-translational modifications of secretory proteins in cultured rat hepatocytes. Weakly basic amines such as methylamine, chloroquine and NH4Cl strongly inhibited not only protein secretion, but also the proteolytic conversion of a proform of complement C3, allowing the precursor to be released into the medium. The amines, h...

The existence of protonated hydroxymethylamines of sec+ ondary amines, RzNHCHtOH, in equilibrium with hydroxymethylamines and protonated amines, has been demonstrated by titration at equilibrium and by rapid titration of the protonated hydroxymethylamines. Analogous compounds, . R3NCHeOH, are formed from formaldehyde and the sterically favorable tertiary amines: pyridine, iv-methylimidazole, an...

The existence of protonated hydroxymethylamines of sec+ ondary amines, RzNHCHtOH, in equilibrium with hydroxymethylamines and protonated amines, has been demonstrated by titration at equilibrium and by rapid titration of the protonated hydroxymethylamines. Analogous compounds, . R3NCHeOH, are formed from formaldehyde and the sterically favorable tertiary amines: pyridine, iv-methylimidazole, an...

In recent years, the use of the Blended Learning (BL) methods has experienced worldwide uptake and is responsible for enormous changes, not only in developed country education, but in developing country education, particularly sub-Saharan Africa. Given the role that blended learning can play in educational development, educational institutions, students, employers, and governments are increasin...

JavaScript is widely used in Web applications; however, its dynamism renders static analysis ineffective. Our JavaScript Blended Analysis Framework is designed to handle JavaScript dynamic features. It performs a flexible combined static/dynamic analysis. The blended analysis focuses static analysis on a dynamic calling structure collected at runtime in a lightweight manner, and refines the sta...

The purpose of this paper is to provide a discussion of the transformative potential of blended learning in the context of the challenges facing higher education. Based upon a description of blended learning, its potential to support deep and meaningful learning is discussed. From here, a shift to the need to rethink and restructure the learning experience occurs and its transformative potentia...

An acoustic wave based-chemical sensor utilizing a crystal substrate and a coating of at least two blended materials is disclosed. The blended materials comprise a combination of (a) a high glass transition temperature polymer or a material of high melting point, and (b) a low glass transition temperature polymer or a material having a low melting point. Transducers are connected to the crystal...