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Abstract  

The molar heat capacities C p,m of 2,2-dimethyl-1,3-propanediol were measured in the temperature range from 78 to 410 K by means of a small sample automated adiabatic calorimeter. A solid-solid and a solid-liquid phase transitions were found at T-314.304 and 402.402 K, respectively, from the experimental C p-T curve. The molar enthalpies and entropies of these transitions were determined to be 14.78 kJ mol−1, 47.01 J K−1 mol for the solid-solid transition and 7.518 kJ mol−1, 18.68 J K−1 mol−1 for the solid-liquid transition, respectively. The dependence of heat capacity on the temperature was fitted to the following polynomial equations with least square method. In the temperature range of 80 to 310 K, C p,m/(J K−1 mol−1)=117.72+58.8022x+3.0964x 2+6.87363x 3−13.922x 4+9.8889x 5+16.195x 6; x=[(T/K)−195]/115. In the temperature range of 325 to 395 K, C p,m/(J K−1 mol−1)=290.74+22.767x−0.6247x 2−0.8716x 3−4.0159x 4−0.2878x 5+1.7244x 6; x=[(T/K)−360]/35. The thermodynamic functions H TH 298.15 and S TS 298.15, were derived from the heat capacity data in the temperature range of 80 to 410 K with an interval of 5 K. The thermostability of the compound was further tested by DSC and TG measurements. The results were in agreement with those obtained by adiabatic calorimetry.

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Citri Grandis Exocarpium (CGE) is a traditional Chinese medicine with a variety of biological activities. For efficient quality control of CGE, a simple, rapid, and accurate high-performance liquid chromatographic (HPLC) method was developed for simultaneous determination of four main compounds (naringin, rhoifolin, meranzin hydrate, and isoimperatorin) in this herb. These four compounds were separated on a C18 column by gradient elution with methanol and water. The flow rate was 1.0 mL·min−1, and the detection wavelength was 324 nm. The recoveries of the method ranged from 96.32% to 103.71%, and good linear relationships (r 2 > 0.9998) over relative wide concentration ranges were obtained. Then this validated method was successfully applied to the analysis of nine batches of CGE samples.

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Chinese endemic wheat landraces possess unique morphological features and desirable traits, useful for wheat breeding. It is important to clarify the relationship among these landraces. In this study, 21 accessions of the four Chinese endemic wheat landrace species were investigated using single-copy genes encoding plastid Acetyl-CoA carboxylase (Acc-1) and 3-phosphoglycerate kinase (Pgk-1) in order to estimate their phylogenetic relationship. Phylogenetic trees were constructed using maximum parsimony (MP), maximum likelihood (ML) and Bayesian, and TCS network and gene flow values. The A and B genome sequences from the Pgk-1 loci indicated that three accessions of Triticum petropavlovskyi were clustered into the same subclade, and the T. aestivum ssp. tibetanum and the Sichuan white wheat accessions were grouped into a separate subclade. Based on the Acc-1 gene, T. aestivum ssp. tibetanum and T. aestivum ssp. yunnanense were grouped into one subclade in the A genome; the B genome from T. petropavlovskyi and T. aestivum ssp. tibetanum, and the Sichuan white wheat complex and T. aestivum ssp. tibetanum were grouped in the same clades. The D genome of T. aestivum ssp. yunnanense clustered with T. petropavlovskyi. Our findings suggested that (1) T. petropavlovskyi is distantly related to the Sichuan white wheat complex; (2) T. petropavlovskyi, T. aestivum ssp. tibetanum and T. aestivum ssp. yunnanense are closely related; (3) T. aestivum ssp. tibetanum is closely related to T. aestivum ssp. yunnanense and the Sichuan white wheat complex; and (4) T. aestivum ssp. tibetanum may be an ancestor of Chinese endemic wheat landraces.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: D. Xu, Q. L. Ning, X. Zhou, C. L. Chen, X. L. Tan, A. D. Wu, and X. Wang

Summary  

Effects of ionic strength and of fulvic acid on the sorption of Eu(III) on alumina were investigated by using a batch technique. The experiments were carried out at T=25±1 °C, pH 4-6 and in the presence of 1M NaCl. The results indicate that sorption isotherms of Eu(III) are linear at low pH values. The sorption-desorption of Eu(III) on alumina at pH 4.4 is reversible, but a sorption-desorption hysteresis is found at pH 5.0. Fulvic acid has an obvious positive effect on the sorption of Eu(III) on alumina at low pH values. The migration of Eu(III) in alumina was studied by using column experiments and 152+154Eu(III) radiotracer at pH 3.8. For column experiments, Eu(III) sorbed on alumina can be desorbed completely from the solid surface at low pH values. The findings are relevant to the evaluation of lanthanide and actinide ions in the environment.

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Journal of Thermal Analysis and Calorimetry
Authors: Z. Xiao, D. Liu, C. Wang, Z. Cao, X. Zhan, Z. Yin, Q. Chen, H. Liu, F. Xu, and L. Sun

Abstract  

The effect of mechanical alloying on Zn-Sb alloy system is investigated with X-ray diffraction (XRD), laser grain size analysis and differential scanning calorimetry (DSC) respectively. The results of laser particle size analysis shows that the particle size decreases with increasing of the grinding time between 0 and 24 h. XRD and DSC results indicate that longer the grinding time of Zn-Sb is, the more content of Zn4Sb3 become in the product in this process.

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A high-speed counter-current chromatography (HSCCC) method was established for the isolation and purification of isochlorogenic acid A from Lonicera japonica Thunb. The two-phase solvent system was composed of n-hexane:ethyl acetate: isopropanol:water (2:3:2:5, v/v/v/v). From 150 mg of the ethyl acetate fraction of L. japonica Thunb, 19.65 mg of isochlorogenic acid A was obtained in a one-step HSCCC separation, with a purity of 99.1%, as determined by high-performance liquid chromatography (HPLC). The structure was further identified by ultraviolet (UV), mass spectrometry (MS) and nuclear magnetic resonance (NMR).

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Abstract  

N,N-dimethylhydroxylamine (DMHA) is a novel salt-free reducing reagent used in the separation U from Pu and Np in the reprocessing of power spent fuel. This paper reports on the radiolysis of aqueous DMHA solution and its radiolytic liquid organics. Results show that the main organics in irradiated DMHA solution are N-methyl hydroxylamine, formaldehyde and formic acid. The analysis of DMHA and N-methyl hydroxylamine were performed by gas chromatography, and that of formaldehyde was performed by ultraviolet–visible spectrophotometry. The analysis of formic acid was performed by ion chromatography. For 0.1–0.5 mol L−1 DMHA irradiated to 5–25 kGy, the residual DMHA concentration is (0.07–0.47) mol L−1, the degradation rate of DMHA at 25 kGy is 10.1–30.1%. The concentrations of N-methylhydroxylamine, formaldehyde and formic acid are (8.25–19.36) × 10−3, (4.20–36.36) × 10−3 and (1.35–10.9) × 10−4 mol L−1, respectively. The residual DMHA concentration decreases with the increasing dose. The concentrations of N-methylhydroxylamine and formaldehyde increase with the dose and initial DMHA concentration, and that of formic acid increases with the dose, but the relationship between the concentration of formic acid and initial DMHA concentration is not obvious.

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Abstract  

Molar heat capacities (C p,m) of aspirin were precisely measured with a small sample precision automated adiabatic calorimeter over the temperature range from 78 to 383 K. No phase transition was observed in this temperature region. The polynomial function of C p,m vs. T was established in the light of the low-temperature heat capacity measurements and least square fitting method. The corresponding function is as follows: for 78 K≤T≤383 K, C p,m/J mol-1 K-1=19.086X 4+15.951X 3-5.2548X 2+90.192X+176.65, [X=(T-230.50/152.5)]. The thermodynamic functions on the base of the reference temperature of 298.15 K, {ΔH TH 298.15} and {S T-S 298.15}, were derived. Combustion energy of aspirin (Δc U m) was determined by static bomb combustion calorimeter. Enthalpy of combustion (Δc H o m) and enthalpy of formation (Δf H o m) were derived through Δc U m as - (3945.262.63) kJ mol-1 and - (736.411.30) kJ mol-1, respectively.

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As one of the world’s earliest domesticated crops, barley is a model species for the study of evolution and domestication. Domestication is an evolutionary process whereby a population adapts, through selection; to new environments created by human cultivation. We describe the genome-scanning of molecular diversity to assess the evolution of barley in the Tibetan Plateau. We used 667 Diversity Arrays Technology (DArT) markers to genotype 185 barley landraces and wild barley accessions from the Tibetan Plateau. Genetic diversity in wild barley was greater than in landraces at both genome and chromosome levels, except for chromosome 3H. Landraces and wild barley accessions were clearly differentiated genetically, but a limited degree of introgression was still evident. Significant differences in diversity between barley subspecies at the chromosome level were observed for genes known to be related to physiological and phenotypical traits, disease resistance, abiotic stress tolerance, malting quality and agronomic traits. Selection on the genome of six-rowed naked barley has shown clear multiple targets related to both its specific end-use and the extreme environment in Tibet. Our data provide a platform to identify the genes and genetic mechanisms that underlie phenotypic changes, and provide lists of candidate domestication genes for modified breeding strategies.

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Journal of Thermal Analysis and Calorimetry
Authors: F. Xu, L. Sun, J. Zhang, Y. Qi, L. Yang, H. Ru, C. Wang, X. Meng, X. Lan, Q. Jiao, and F. Huang

Abstract  

Heat capacities of the carbon nanotubes (CNTs) with different sizes have been measured by modulated temperature differential scanning calorimetry (MDSC) and reported for the first time. The results indicated the values of C p increased with shortening length of CNTs when the diameters of CNTs were between 60 and 100 nm. However, the values of C p of CNTs were not affected by their diameter when the lengths of CNTs were 1–2 um, or not affected by the length of CNTs when their diameters were below 10 nm. The thermal stabilities of the CNTs have been studied by TG-DTG-DSC. The results of TG-DTG showed that thermal stabilities of CNTs were enhanced with their diameters increase. With lengths increase, the thermal stabilities of CNTs increased when their diameters were between 60 and 100 nm, but there is a slight decrease when their diameters were less than 60 nm. The further DSC analyses showed both released heat and T onset increased with the increase of CNTs diameters, which confirms the consistency of the results from both TG-DTG and DSC on CNTs thermal stability.

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