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- Author or Editor: W. Liu x
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Abstract
Zinc formate dihydrate has been synthesized and characterized by powder X-ray diffraction, elemental analysis, FTIR spectra and thermal analysis. The molar heat capacity of the coordination compound was measured by a temperature modulated differential scanning calorimetry (TMDSC) over the temperature range from 200 to 330 K for the first time. The thermodynamic parameters such as entropy and enthalpy vs. 298.15 K based on the above molar heat capacity were calculated. The thermal decomposition characteristics of this compound were investigated by thermogravimetric analysis (TG) and differential scanning calorimetry (DSC). TG curve showed that the thermal decomposition occurred in two stages. The first step was the dehydration process of the coordination compound, and the second step corresponded to the decomposition of the anhydrous zinc formate. The apparent activation energy of the dehydration step of the compound was calculated by the Kissinger method using experimental data of TG analysis. There are three sharply endothermic peaks in the temperature range from 300 to 650 K in DSC curve.
Abstract
Phase behavior of dodecane–tetradecane (n-C12H26–C14H30, n-C12–C14) binary system in bulk and confined in SBA-15 (pore diameters 8 nm; 15.9 nm) has been investigated by differential scanning calorimetry and transmission electron microscopy. The bulk system possesses some special phases relating to the rotator phase in normal alkanes. Dodecane–tetradecane mixtures confined in SBA-15 (8 nm) are a system miscible both in solid and liquid states with a phase diagram of a smooth curve. Dodecane–tetradecane system confined in SBA-15 (15.9 nm) exhibits not only solid–liquid (s–l) in all compositions but solid–solid transition in mole fractions of tetradecane 0.1–0.6, which forms a phase diagram of “loop line” shape. Melting temperatures of n-C12–C14/SBA-15 (8 nm) are lower than those of n-C12–C14/SBA-15 (15.9 nm) in all mole fractions. The evolution of the phase diagram of n-C12–C14 confined in 8 nm, 15.9 nm pore sizes of SBA-15 and in bulk, respectively, shows a dramatic effect of confinement on phase behavior of normal alkane mixtures. The s–l phase boundary lines of n-C12–C14/SBA-15 (8, 15.9 nm) are fitted as 
being [
], where D is a polynomial ∑ a
i
x
i
, i = 1, 2,···, n (A = C14, B = C12).
Abstract
Bis(1-octylammonium) tetrachlorocuprate (1-C8H17NH3)2CuCl4(s) was synthesized by the method of liquid phase reaction. The crystal structure of the compound has been determined by X-ray crystallography. The lattice potential energy was obtained from the crystallographic data. Molar enthalpies of dissolution of (1-C8H17NH3)2CuCl4(s) at various molalities were measured at 298.15 K in the double-distilled water by means of an isoperibol solution-reaction calorimeter, respectively. In terms of Pitzer's electrolyte solution theory, the molar enthalpy of dissolution of (1-C8H17NH3)2CuCl4(s) at infinite dilution was determined to be 
and the sums of Pitzer's parameters 
and 
were obtained.
Abstract
Prorocentrum donghaiense caused large-scale red tides off Chinese coast in recent years. Expressed sequence tag (EST) analysis was carried out for this dinoflagellate in order to identify the genes involved in its proliferation and death. A cDNA library was constructed for P. donghaiense at late exponential growth phase, and 308 groups of EST were generated, which include 36 contigs and 272 singletons. Among 22 groups showed homologies with known genes, 2 matched significantly with caspase and proliferating cell nuclear antigen. Caspase and proliferating cell nuclear antigen are 2 key proteins involved in programmed cell death. Their identification evidenced preliminarily the induction of PCD in aging P. donghaiense. The identified included also calmodulin and protein phosphatase, two proteins involved in diverse cell processes including PCD by binding to or modifying others.
A reborn interest has occurred during the last decade toward wheat landraces for broadening genetic basis of modern wheat cultivars. The investigation of molecular traits within and between existing landraces of wheat can help scientists to develop appropriate strategies for their efficient maintenance and exploitation. The present study dealt with the gliadin characterization of forty-seven wheat landraces collected from wheat mainly planted areas of China, each of which was represented by a sample of at least 43 individuals. Twelve accessions selected on the basis of gliadin analysis were investigated further using 21 SSR markers. The results proved that landraces of wheat are a mixture of variable individuals genetically distinguishable from each other. Twelve of the analyzed 47 accessions were observed to be homogeneous, while 35 (74.5%) of them were heterogeneous in their gliadin composition. In total, 122 gliadin pattern were observed. On average, 10.1% (Gst) of the total variation arose from differentiation among regions, and 89.9% was attributed to within-region variation. Furthermore, nineteen of the 21 SSR markers were polymorphic across all the populations. The total number of the amplified DNA products was 110, with a mean of 6.11 alleles per locus. The values of genetic diversity within each landrace population varied from 0.006 to 0.351. Implications for the management of this valuable genetic resource are discussed.
Youzimai is a widespread wheat landrace and has been used extensively in breeding programs in China. In order to assess the genetic variation between and within Youzimai accessions, samples of 31 landrace accessions of wheat, all called ‘Youzimai’, were collected from 6 geographic regions in China and evaluated using morphological traits, seedling resistance to powdery mildew, gliadin and microsatellite markers. Typical differences among accessions were observed in morphological characteristics. Forty-five (58.4%) of 77 assayed SSR markers showed polymorphism over the entire collection and total 226 alleles were identified with an average of 5.02 alleles per locus. SSR data indicated that the accessions from Hebei province were the most diverse, as evidenced by greatest number of region-specific alleles and highest diversity index. These accessions, therefore, probably experienced the most substantial morphological and molecular evolution as a result of various natural and anthropomorphic influences. On the other hand, differentiation in gliadin phenotypes was found among seeds within 80.6% of total accessions and average 61.5% of entire collections showed heterogeneous and comprised resistant plants in reaction to powdery mildew, suggesting the presence of a wide diversity within the wheat landrace. By developing an intimate knowledge of the available wheat genotypes, appropriate selections can be made for commercial application in order to conserve and exploit the diversity of the wheat landraces.
Purple pericarp is an interesting and useful trait in Triticum aestivum, but the molecular mechanism behind this phenotype remains unclear. The allelic variation in the MYB transcriptors is associated with the phenotype of pigmented organs in many plants. In this study, a MYB transcription factor gene, TaMYB3, was isolated using homology-based cloning and a differentially expressed gene mining approach, to verify the function of the MYB transcriptor in the purple pericarp. The coding sequence of TaMYB3 in cultivar Gy115 was the same as that in cultivar Opata. TaMYB3 was localized to FL0.62–0.95 on chromosome 4BL. The TaMYB3 protein contains DNA-binding and transcription-activation domains, and clustered on a phylogenetic tree with the MYB proteins that regulates anthocyanin and proanthocyanin biosynthesis. TaMYB3 localized in the nuclei of Arabidopsis thaliana and wheat protoplasts after it was transiently expressed with PEG transformation. TaMYB3 induced anthocyanin synthesis in the pericarp cells of Opata in the dark in collaboration with the basic helix–loop–helix protein ZmR, which is also the function of ZmC1. However, TaMYB3 alone did not induce anthocyanin biosynthesis in the pericarp cells of the white grain wheat cultivar Opata in the light after bombardment, whereas the single protein ZmR did. Light increased the expression of TaMYB3 in the pericarp of Gy115 and Opata, but only induced anthocyanin biosynthesis in the grains of Gy115. Our results extend our understanding of the molecular mechanism of the purple pericarp trait in T. aestivum.
Effects of retorting factors on combustion properties of shale char
Part 4. Combustion characteristics
Abstract
For obtaining high shale oil yield as well as treating shale char efficiently and in an environmentally friendly way in a new comprehensive utilization system of oil shale, a series of fundamental experiments have been conducted for exploring the effects of retorting factors on shale oil yield and shale char characteristics. Based on these previous studies, in this article, combustion experiments of shale chars obtained under various retorting conditions were performed with a Q5000IR thermogravimetric analyzer and a Leitz II-A heatable stage microscope and the effects of retorting factors were discussed on the combustion characteristics of shale char. Among four studied retorting parameters, retorting temperature and residence time exert very significant influence on the combustion characteristics of shale char. Either elevating the retorting temperature from 430 to 520 °C or lengthening the residence time at a low retorting temperature will largely decrease residual organic matters within shale char, resulting in decreasing mass loss in the low-temperature stage of combustion process of shale char, an elevation of ignition temperature and a shift of ignition mechanism from homogeneous to heterogeneous. One set of retorting condition was also recommended as a reference for designing the comprehensive utilization system of oil shale studied in this work: retort temperature of 460–490 °C, residence time of 20–40 min, particle size of <3 mm, and low heating rate of <10 °C/min.
Summary
Oroxylin A (5,7-dihydroxy-6-methoxyflavone), which has showed multiple pharmacological effects, was semi-synthesized chemically as a pharmaceutical agent. Its impurities, degradation products and their formation pathways remain unknown. In the present study, two impurities (5,6,7-trihydroxyflavone, 5-hydroxy-6,7-dimethoxytlavone) and a degradation product (5,7-dihydroxy-8-methoxyflavone) in Oroxylin A bulk drug substance were identified, and their formation pathways were proposed. A reversed phase liquid chromatographic method for the simultaneous determination of Oroxylin A and the three compounds was developed on a C18 column using methanol-acetonitrile-0.1% acetic acid (54:23:23, v/v/v) as the mobile phase. The detection was performed at 271 nm. The method was validated to be robust, precise, specific and linear between 4 and 40 μg mL−1; the limits of detection and quantification of Oroxylin A were 0.01 and 0.04 μg mL−1, respectively. The developed method was found to be suitable to check the quality of bulk samples of Oroxylin A at the time of batch release and also during its stability studies (long term and accelerated stability).
