Through the combination of surface sensitive photoelectron spectroscopy and molecular dynamics simulation, the relative surface propensities of guanidinium and ammonium ions in aqueous solution are characterized. The fact that the N 1s binding energies differ between these two species was exploited to monitor their relative surface concentration through their respective photoemission intensitie...

Quaternary ammonium ions were applied to the inside of single myelinated nerve fibers by diffusion from a cut end. The resulting block of potassium channels in the node of Ranvier was studied under voltage-clamp conditions. The results agree in almost all respects with similar studies by Armstrong of squid giant axons. With tetraethylammonium ion (TEA), pentyltriethylammonium ion (C(5)), or non...

a new polymorph crystalline silica composition having uniform pore dimensions were synthesized by calcining a crystalline hydrated alkyl-ammonium silicate. the pore dimensions approximately were 6 angstrom for silicalite-1 and 11 angstrom for silicalite-2 units. the silicalite-1 was prepared hydrothermally at a ph of about 10 from a reaction mixture consist of water, amorphous silica and a quat...

Hydration of the ammonium ion plays a key role in determining the biomolecular structure as well as local structure of water in aqueous environments. Experimental data obtained by cryogenic ion mobility-mass spectrometry (cryo-IM-MS) show that dehydration of alkyl diammonium cations induces a distinct unfolding transition at a critical number of water molecules, n = 21 to 23, n = 24 to 26, and ...

The effects of light, 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), and ammonium ion on pool sizes of ATP were studied in Lemna paucicostata 6746 (wild type) and a photosynthetic mutant (strain 1073) with abnormal flowering responses. Wild type fronds were capable of endogenous and phenazine methosulfate-catalyzed cyclic photophosphorylation. The endogenous cyclic photophosphorylation was inh...

In order to know the relationship between inorganic ion composition of saliva and dental caries prevalence, saliva from children was studied. The saliva samples were collected from 30 subjects aged 3 to 18 years. Each inorganic ion concentration and pH of saliva was measured and their relationship to dental caries was studied. The results were as follows: 1. Significant relationship was noted b...

Eight quaternary ammonium compounds were tested for their ability to induce contact dermatitis in guinea pigs by using a modified Freund's complete adjuvant test together with the guinea pig maximization test. Only two quaternary ammonium salts of the eight tested could be designated as strong allergens. These two active substances were shown to be capable of stable association with membrane li...

The most promising technologies to remove perchlorate from water are ion exchange and biological reduction. Although successful, ion exchange only separates perchlorate from water; it does not eliminate it from the environment. The waste streams from these systems contain the caustic or saline regenerant solutions used in the process as well as high levels of perchlorate. Biological reduction c...