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The absorption of three amino acids (leucine, alanine and lysine) from the washed, closed rumen was studied in a short-term (75 min) experiment in situ. The concentration of leucine and alanine did not change in the rumen during the experiment, while that of lysine continuously decreased, and 40% of the total lysine placed in the rumen was absorbed during the experimental period. The rate of absorption decreased in proportion to the fall of amino acid concentration.

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Abstract  

The complexes of rare earth bromides with alanine, REBr33AlanH2O (RE=Ce, Pr, Sm, Eu, Gd and Tb, n=3; RE=Dy and Y, n=2.5 Ala=alanine), were prepared and characterized by means of chemical analysis, elemental analysis, molar conductivity, thermogravimetry, IR spectra and X-ray diffraction. The thermal decomposition in N2 of these complexes was studied by means of TG-DTG techniques from ambient temperature to 1000C. During heating, the hydrated complexes of Ce, Pr and Y lose waters in one step, but the hydrated complexes of Sm, Eu, Gd, Tb and Dy lose waters in two steps. Then anhydrous complexes lose 2.5 alanine molecules except the complexes of Eu which lose three alanine molecules. Apparently, only be complex of Eu has an intermediate, EuOBr. All complexes finally decompose to oxides.

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Alanine- and taurine-salicylal Schiff base complexes of magnesium

Synthesis, characterization and thermal decomposition

Journal of Thermal Analysis and Calorimetry
Authors: S. Luan, Y. Zhu, and Y. Jia

Abstract  

The complexes of α-alanine-salicylal Schiff base of magnesium (α-ASSM), β-alanine-salicylal Schiff base of magnesium (β-ASSM) and taurine-salicylal Schiff base of magnesium (TSSM) were synthesized. The formulae of the complexes are Mg[OC6H4CHNCH(CH3)COO]·2H2O, Mg[OC6H4CHNCH2CH2COO]·2H2O and Mg[OC6H4CHNCH2CH2SO3]·2H2O. The crystal structure belongs to orthorhombic system with the lattice parameters: a=1.6954 nm, b=2.0873 nm and c=2.3037 nm for the β-ASSM, to orthorhombic system with the lattice parameters: a=1.5586 nm, b=1.8510 nm and c=2.6240 nm for the β-ASSM, to monoclinic system with the lattice parameters: a=1.3232 nm, b=1.4960 nm, c=2.1543 nm and β=98.04° for the TSSM, respectively. The results of the thermal decomposition processes and infrared spectra of the complexes show that the complexes may possess different coordination structures.

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Abstract  

The solid-state coordination reactions of lanthanum chloride with alanine and glycine, and lanthanum nitrate with alanine have been studied by classical solution calorimetry. The molar dissolution enthalpies of the reactants and the products in 2 mol L-1 HCl solvent of these three solid-solid coordination reactions have been measured using an isoperibol calorimeter. From the results and other auxiliary quantities, the standard molar formation enthalpies have been determined to be Δf H m θ[La(Ala)3Cl33H2O(s), 298.2 K]= -3716.3 kJ mol-1, Δf H m θ [La(Gly)3Cl35H2O(s), 298.2 K]= -4223.0 kJ mol-1 and Δf H m θ [La(Ala)4(NO3)3H2O(s), 298.2 K]= -3867.57 kJ mol-1, respectively.

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Abstract  

Four complexes of rare earth bromides with amino acids, REBr3·3L·3H2O (RE=La, Nd;L=glycine or alanine) were prepared and characterized by means of chemical analysis, elemental analysis, molar conductivity, thermogravimetry, IR spectra and X-ray diffraction. Their thermal decomposition kinetics from ambient temperature to 500°C were studied by means of TG-DTG techniques under non-isothermal conditions. The kinetic parameters (activation energyE and pre-exponential constantA) and the most probable mechanisms of thermal decomposition were obtained by using combined differential and integral methods. The thermal decomposition processes of these complexes are distinguished as being of two different types, depending mainly on the nature of the amino acid.

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Abstract  

The solid-state coordination reaction: Nd(NO3)36H2O(s)+4Ala(s) → Nd(Ala)4(NO3)3H2O(s)+5H2O(l) and Er(NO3)36H2O(s)+4Ala(s) → Er(Ala)4(NO3)3H2O(s)+5H2O(l) have been studied by classical solution calorimetry. The molar dissolution enthalpies of the reactants and the products in 2 mol L–1 HCl solvent of these two solid-solid coordination reactions have been measured using a calorimeter. From the results and other auxiliary quantities, the standard molar formation enthalpies of [Nd(Ala)4(NO3)3H2O, s, 298.2 K] and[Er(Ala)4(NO3)3H2O, s,298.2 K] at 298.2 K have been determined to be Δf H m 0 [Nd(Ala)4(NO3)3H2O,s, 298.2 K]=–3867.2 kJ mol–1, and Δf H m 0 [Er(Ala)4(NO3)3H2O, s, 298.2 K]=–3821.5 kJ mol–1.

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Abstract  

Irradiation of solid polycrystalline alanine creates a free radical, whose concentration can be measured from its ESR signal. The radical CH3 HCOO of practically unlimited stability at room temperature shows an electronic absorption spectrum in the UV. Modern methods of diffuse reflectance spectrophotometry allow to measure the radical concentration which is proportional to the absorbed dose of radiation. The alanine dosimeter is prepared in a thin layer, adequate both for the congested isodose curves in the case of accelerated electrons irradiation and the method of measurement. Thus the proposed dosimeter is applicable not only for gamma, but also for EB radiation processing in the range of 0.1 to 50 kGy. The application of the dosimeter does not demand to use the ESR spectrometer, even of the type dedicated to alanine dosimetry only, but may be performed by a UV-VIS spectrophotometer equipped with an integrating sphere, permitting measurements of the Kubelka-Munk function.

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acid compounds such as l -argininium dinitrate [ 6 ], l -arginine hydrochloride [ 7 ], l -alanine acetate [ 8 ], and glycine sodium nitrate [ 9 ] have been reported. The amino acid l -alanine forms a number of complexes in coordination with

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series, namely: glycine, l -alanine, and l -proline. However, the solubility of proline in water is much higher than even glycine and its enthalpy of solution in water is exothermic unlike other amino acids. It was shown that in terms of heat capacity

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Abstract  

The objects of investigation were single crystals of L-α-alanine, in which radical anion CH3 C˙H CO 2 has been formed by radiation induced deamination of alanine. Previously, this stable radical has been spectrally identified (λmax, ε=1100 M−1·cm−1), and its characteristics have found to be identical with characteristics of the same radical obtained by pulse radiolysis in aqueous solution. The mechanism of radical formation in the solid state is not known. Time resolved pulse radiolysis of single crystal alanine has shown more complicated way of the formation of the same radical in solid state than in aqueous solution. The electrons abstracted from the solid alanine molecule neutralise positive of zwitter-ion alanine. Ammonia is leaving the reaction-complex in time of milliseconds, leaving the stable radical anion.

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