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  • Author or Editor: P. Yu x
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Complex cell walls of barley hulls contain phenolic constituents — hydroxycinnamic acids, mainly ferulic acid (3-methoxy-4-hydroxy-cinnamic acid, FA) and para-coumaric acid (4-hydroxycinnamic acid, PCA). Ferulic acid is produced via the phenylpropanoid biosynthetic pathway and is covalently cross-linked to polysaccharides by ester bonds and to components of lignin mainly by ether bonds. Various studies have consistently indicated that FA is among the factors most inhibitory to the biodegradability of plant cell wall polysaccharides. PCA is also covalently linked to polysaccharides (minor) and lignin (major), but PCA does not form the inhibitory cross-linkages as FA does. It is considered to represent plant cell wall lignification. The objective of this study was to determine the genotypic variation and magnitude of difference in the concentration of the hydroxycinnamic acids in terms of FA and PCA as well as their ratios in barley hull and seeds in sixteen varieties of barley collected during three years. These data will be correlated to barley nutrient availability in future study. The barley varieties included CDC Cowboy, Valier, TR251, Newdale, RCSL97, KXN/TLN-147 (AU), WABAR2160 (AU), Harrington, CDC Copeland, CDC Kendall, AC Metcalfe, CDC Dolly, McLeod, CDC Bold, CDC Helgason and CDC Trey. The focus of this study was on ferulic acid because of its inhibitory effect on rumen degradation and digestion which are highly related to nutrient availability in animals. The results showed significant differences (P < 0.01) a mong the barley varieties in ferulic acid and p-coumaric acid and their ratio. Whole barley seed contained higher (P<0.05) ferulic acid concentration than p-coumaric acid, ranging from 509 to 679 μg/g DM for ferulic acid and 131 to 345 μg/g DM for p-coumaric acid. The ratios of ferulic acid to p-coumaric acid ranged from 1.8 to 3.9. The ferulic acid concentration in hull was higher (P < 0.05) than that in whole seed, ranging from 2,320 to 4,206 μg/g DM. Percentage of ferulic acid content in hull and dehulled seed ranged from 38 to 70% and 30 to 62%, respectively. Growth year affect affected the hydroxycinnamic acid profiles in barley seed and hull. In conclusion, there were large differences in the ferulic acid and para-coumaric acid among the barley varieties indicating genotypic variation. Harrington contained highest and Valier contained lowest FA in whole seed. Barley TR251 contained lowest % of FA content in the hull and highest % of FA content in the dehulled seed. Future study is needed to understand the relationship between the hydroxycinnamic acid profile in barley seeds and hull and nutrient utilization and availability of barley in animals.

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A numerical study of the thermodynamic properties of a superconducting quantum cylinder in a longitudinal magnetic field is carried out. Closed-form expressions for the critical temperature, the free energy, the heat capacity jump, and the magnetization difference between the superconducting and normal phases as functions of the nanotube parameters are obtained in limit cases.

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Summary By employing a novel idea and simple techniques, we substantially generalize the Turán type inequality for rational functions with real zeros and prescribed poles established by Min [5] to include L p spaces for 1≤ p ≤ ∞ while loosing the restriction ρ > 2 at the same time.

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Abstract  

We present an improved methodology for a thermal transient method enabling simultaneous measurement of thermal conductivity and specific heat of nanoscale structures with one-dimensional heat flow. The temporal response of a sample to finite duration heat pulse inputs for both short (1 ns) and long (5 μs) pulses is analyzed and exploited to deduce the thermal properties. Excellent agreement has been obtained between the recovered physical parameters and computational simulations through choosing an optimized pulse width.

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Journal of Thermal Analysis and Calorimetry
Authors: Yu. K. Godovsky and V. P. Privalko
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A thermodynamic analysis of the uniaxial stretching of polyurethanes of various compositions and mechanical histories was carried out by using deformation calorimetry. The initial small strain deformations were found to result from the volume elasticity of the hard phase. The intramolecular energy contributions of the soft blocks were estimated. The hard block contributions were shown to depend on their content and on the degree of sample stretching. The predominant role of the soft component is proved to be manifested only in softened samples with a hard block content not exceeding 30%. The thermodynamics of the softening and hysteresis phenomena were studied. The dependence of the deformation mechanism on the hard block content and mechanical history is discussed.

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Effects of the nature of functional groups (namely, hydroxyl, methyl, silicon hydride, amino, and vinyl) on the surface of pristine and modified silicas on polymerization of 2-hydroxyethylmethacrylate (HEMA) and on structural characteristics of the filled composites have been studied. DSC, FTIR spectroscopy and equilibrium water sorption (ESI) techniques were applied for the composites characterization. Results obtained testify that the chemical nature of the grafted groups has a strong influence on the monomer orientation in the surface layer of the filler. More uniform and cross-linked structures were detected in the composites with particularly methylated silica. Filler with chemically active silicon hydride groups promotes formation of ordered structure with rigid macromolecules. The presence of amino and vinyl groups on the silica surface results in formation of flexible polymer chains with a low cross-linking density or with a low polymerization degree, even at 2 wt% filling degree. Water uptake for composites with vinyl- and amine-containing silicas was low, indicating the close-packing of polymeric molecules in the filled polyHEMA.

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Journal of Thermal Analysis and Calorimetry
Authors: V. M. Egorov, Yu. M. Baykov, V. A. Bershtein, Yu. P. Stepanov and F. A. Chudnovskii

DSC investigations have been performed for a series of compounds Ba2YCu3Oy with the oxygen content varying in the rangey=6.0...6.9 by means of various heat treatments at 800–1200 K followed by quenching, or through the chemical extraction of oxygen by placing the sample in dihydrogen at 470–490 K. The sample preserving a constant oxygen content during heating in nitrogen exhibited exothermal effects between 450 and 850 K. It has been shown that the ΔH vs. y function reaches maximum aty ≈ 6.5. Kinetic measurements have shown that the diffusive mobility of oxygen atoms in the lattice is responsible for these effects, viz. the Arrhenius and cooperative processes of reorganization in the non-equilibrium oxygen subsystem of the bulk.

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Abstract

Novel double complex salts [M(NH3)5Br][AuBr4]2·nH2O, M = Rh, Ir, have been synthesized and examined. The processes of thermal decomposition of the compounds in inert and reductive atmospheres have been studied and intermediate products identified. Simultaneous thermal analysis with parallel mass-spectrometric analysis of evolved gases (STA-EGA) has been employed for identification of main gaseous products of thermolysis in inert atmosphere. It has been revealed that the final products of decomposition in inert or reductive atmospheres are fine powders of gold and the corresponding platinum metal with sizes of crystallites 4–40 nm. The possibility of preparation of the metastable solid solution Au0.05Ir0.95 on thermolysis of [Ir(NH3)5Br][AuBr4]2·H2O in inert atmosphere has been demonstrated.

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