Ammonium ions are ubiquitous in chemistry and molecular biology. Considerable efforts have been undertaken to develop synthetic receptors for their selective molecular recognition. The type of host compounds for organic ammonium ion binding span a wide range from crown ethers to calixarenes to metal complexes. Typical intermolecular interactions are hydrogen bonds, electrostatic and cation-π in...

Soybean cell suspension cultures grew on defined media with ammonium as the sole nitrogen source if Krebs cycle acids were added. Satisfactory growth was obtained with ammonium salts of citrate, malate, fumarate, or succinate, when compared with the regular medium containing nitrate and ammonium. Little or no growth occurred when ammonium salts of shikimate, tartrate, acetate, carbonate, or sul...

The present-day wastewater treatment practices can be significantly improved through the introduction of new microbial treatment technologies. Recently, several new processes for nitrogen removal have been developed. These new nitrogen removal technologies provide practicable options for treating nitrogen-laden wastewaters. The new processes are based on partial nitrification of ammonium to nit...

Ammonium production in the presence of specific inhibitors of sulfate reduction and methanogenesis was investigated in six marine sediments which differed in bulk properties and organic matter input. In all cases, little effect of the inhibitors on ammonium production was observed, although sulfate reduction was suppressed by molybdate. This gives evidence that the processes of fermentation and...

catalytic amount of ce(iv) as ceric triethylammonium nitrate (ctean) in dichloromethane or acetone can bring about an efficient tetrahydropyranylation of different types of alcohols to afford the corrsesponding tetrahydropyranyl ethers in high yields. deportection of tetrahydropyranyl ethers can also be achieved efficiently in the presence of this catalyst in methanol.

The metabolic capability of denitrifying sludge to oxidize ammonium and p-cresol was evaluated in batch cultures. Ammonium oxidation was studied in presence of nitrite and/or p-cresol by 55 hours. At 50 mg/L NH4 + -N and 76 mg/L NO2 -N, the substrates were consumed at 100% and 95%, respectively, being N2 the product. At 50 mg/L NH4 + -N and 133 mg/L NO2 -N, the consumption efficiencies decrease...

Isolation of bacteria able to utilize s-triazines as the sole and limiting nitrogen sources for growth is described. Three strains of Pseudomonas (A, D, and F) and two strains of Klebsiella pneumoniae (90 and 99) were examined. Strains D and F utilized N-ethylammelide, N-isopropylammelide, ammeline, ammelide, cyanuric acid, and ammonium ion as nitrogen sources. Strain A utilized melamine, ammel...

N,N-didecyl-N-methyl-poly(oxyethyl) ammonium propionate is a quaternary ammonium compound that is used to disinfect medical devices. Occupational allergic contact dermatitis caused by quaternary ammonium compounds in healthcare workers is an increasingly important issue (1). We report a case of severe allergic contact dermatitis caused by N,N-didecyl-N-methyl-poly(oxyethyl) ammonium propionate ...