The title compound, propane-1,3-diammonium tetravanadate, (C3H12N2)[V4O10], represents a second polymorph of composition beta-[H3N(CH2)3NH3][V4O(10)]. It differs from the alpha polymorph [Riou & Ferey (1995). J. Solid State Chem. 120, 137-145] in the conformation of the propane-1,3-diammonium dication which, in the present example, lies on a twofold axis and adopts a syn-syn rather than a syn-a...

A rapid graphite-furnace atomic absorption spectrophotometric procedure is described for determining cadmium and lead in heparinized human whole blood. A known aliquot of the blood sample is diluted fivefold with an aqueous solution composed of 5 g each of diammonium hydrogen phosphate and Triton X-100 per liter, the solution is vigorously agitated, and a 10-microL aliquot is injected into a py...

To develop appropriate measures and means of fire protection at facilities, it is relevant to form an idea the phenomenology processes occurrence, evolution, termination combustion. This paper proposes procedures for building mathematical models energy component those physicochemical that occur in wood under influence fire, which make possible determine time from beginning such impact onset pha...

In the title compound, [NH(3)(CH(2))(5)NH(3)][PdCl(4)], the square-planar [PdCl(4)](2-) anions are centrosymmetric while the diammonium cation lies in a general position. In addition to electrostatic inter-actions, the two species are linked through N-H⋯Cl hydrogen bonds to form a three-dimensional network.

The invariance principle of enzyme enantioselectivity must be absolute because it is absolutely essential to the homochiral biological world. Most enzymes are strictly enantioselective, and tryptophanase is one of the enzymes with extreme absolute enantioselectivity for L-tryptophan. Contrary to conventional knowledge about the principle, tryptophanase becomes flexible to catalyze D-tryptophan ...

Hydroxyapatite powder has been prepared via sol-gel procedure using calcium nitrate tetrahydrate and diammonium hydrogen phosphate as the precursors for calcium and phosphorus, respectively. XRD measurement shows that the powder contains hydroxyapatite crystals with β-TCP and calcium oxide as secondary phases. Hydroxyapatite powder of higher purity, i. e., the correct Ca/P ratio, has been obtai...

Tryptophanase, an enzyme with extreme absolute stereospecificity for optically active stereoisomers, catalyzes the synthesis of l-tryptophan from l-serine and indole through a beta-substitution mechanism of the ping-pong type, and has no activity on d-serine. We previously reported that tryptophanase changed its stereospecificity to degrade d-tryptophan in highly concentrated diammonium hydroge...

The title compound 2C(8)H(14)N(2) (2+)·[B(14)O(20)(OH)(6)](4-), contains diprotonated C(8)H(14)N(2) (2+) cations and centrosymmetric tetra-deca-borate anions. The crystal structure is stabilized by O-H⋯O and N-H⋯O hydrogen bonds.