Potassium/calcium dating

Coleman ML (1971) Potassium-calcium dates from pegmatitic micas. Earth Planet Sci Lett 12 399-405 Condie KC (1993) Chemical composition and evolution of the upper continental crust contrasting results from surface samples and shales. Chem Geol 104 1-37... 

Date pulp is low in fat and protein but rich in sugars, mainly fructose and glucose, making it a potent source of caloric energy. It contains excellent amounts of amino acids for protein dietary minerals such as selenium, potassium, calcium, magnesium, manganese, and iron several B vitamins vitamin C omega fatty acids phytosterols and both insoluble and prebi-... 

UHT processing and storage have no effect on the total calcium content or calcium bioavailability. Calcium, phosphorus, and magnesium are shown to be equally bioavailable to rats from UHT milk, raw milk, and traditionally processed milk (Katz et al. 1981). Also, human infants retain similar amounts of calcium, potassium, and phosphorus whether fed UHT milk or conventionally pasteurized milk (Renner 1980 Mehta 1980). Data to date indicate no significant changes in the nutritional value of UHT milk under controlled heat treatment and subsequent storage. 

The use of oxidizers, such as potassium bromate, potassium iodate, and calcium peroxide as dough modifiers in the baking industry dates back many years. However, their mechanism has not been fully explained. Among authorities, there are at least two major viewpoints. It has been proposed that oxidizers inhibit proteolytic enzymes present in flour. It has also been proposed that the number of —S—S—bonds between protein chains is increased, forming a tenacious network of molecules, This action... 

The calcium-40 is not useful for radioactive dating because it cannot be distinguished from other calcium in the rock. The argon-40, however, can be measured. Figure 17 shows the decay of potassium-40 through four half-lives. 

This is a calcium-channel antagonist, which can produce potentiation of suxamethonium and non-depolarizing neuromuscular blockers at doses within the therapeutic range. Verapamil also exacerbates the increase in serum potassium levels after the administration of suxamethonium. To date, there are no established data about such interactions between other calcium-channel blockers and... 

Acetic acid INS No 260, FW 60.05 Chem. name ethanoic acid. The preservation of foods with acetic acid is an old technique that dates back to centuries. It is the main acid of vinegar and constitutes approximately 4%. It can be produced by fermentation or also by the oxidation of acetaldehyde, methanol, and carbon dioxide. The functional uses are as an acidifler and flavoring agent. The ADI is not limited for acetic acid and for its potassium and sodium salts [46], Potassium, sodium, and calcium salts of acetic acid are commonly used. 

Pectins " are high molecular weight polysaccharides with at least 65 wt% of a-(1 4)-linked d-galacturonic acid-based units, which may exist as free acid, salt (calcium, sodium, potassium, ammonium, etc.), naturally esterified with methanol, or as acid amide in ami-dated pectins. 

Two cannabinoid (CB) receptors with about 40 % homology have been identified and cloned to date, namely CBi and CB2. These receptors belong to the superfamily of G-protein coupled membrane receptors [29] and consequently they show a typical heptahelical structure. Interaction with cannabinoid receptors stimulates a cascade of signal transduction pathways, including interaction with potassium and calcium channels (for CBi) and several kinases (e.g., MAP kinase). Since a number of cannabinoid-Uke effects persist in CB1/CB2 knockout mice, the existence of other cannabinoid receptors different from CBi and CB2 has been suggested (e.g., GPR55) [[30], [31]], but their effective role still awaits to be clearly defined. 

Other compounds found in association include glaucophane and riebeckite, which have been identified in material from Knossos, Crete, dated to 2100 BC, and Thera (Santorini 1500 Bc) (Filippakis ei a/., 1976 Cameron ci /., 1977 Profie/a/., 1977). Differences in the compositions of samples from various geographical sources have also been noted in analyses. Tite et al. (1984), for example, have shown how Egyptian and Roman specimens have excess calcium oxide and higher alkali levels while Nimrud samples have an excess of copper(II) oxide and low concentrations of potassium and sodium. All samples seem to contain more silicon dioxide than required for stoichiometry. 

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