Polyaniline/multi-walled carbon nanotube (PANI/MWNT) composites were prepared by in situ polymerization. Transmission electron
microscope (TEM), X-ray diffraction (XRD) and Fourier transform infrared (FTIR) were used to characterize the PANI/MWNT composites.
Thermal stability and glass transition temperature (Tg) were measured by thermogravimetry (TG) and temperature modulated differential scanning calorimetry (TMDSC), respectively.
The TG and derivative thermogravimetry (DTG) curves indicated that with augment of MWNTs content, the thermal stability of
PANI/MWNT composites increased continuously. While, Tg increased and then decreased with the MWNTs content increasing from 0 to 20 mass%.
Polyaniline/α-Al2O3 (PANI/α-Al2O3) composites were synthesized by in situ polymerization through ammonium persulfate ((NH4)2S2O8, APS) oxidized aniline using HCl as dopant. XRD and FTIR were used to characterize the PANI/α-Al2O3 composites. The thermal stabilities and glass transition temperature (Tg) of PANI/α-Al2O3 composites were tested using thermogravimetric (TG) method and modulated differential scanning calorimetry (MDSC) technique.
The results of TG showed that the thermal stability of PANI/α-Al2O3 composite increased and then decreased with the increase in α-Al2O3 content. The derivative thermogravimetry (DTG) curves showed one step degradation of PANI when the α-Al2O3 content was lower than 52.5 mass%, and exhibited two steps degradation when the α-Al2O3 content was higher than 63.6 mass%. The MDSC curves showed that the Tg of PANI/α-Al2O3 composites increased and then decreased with the augment of α-Al2O3 for the interaction between PANI chains and the surface of α-Al2O3.
Authors:X. Zhang, C. Shi, J. Wu, S. Yue, and Y. Qi
Developmental genetics of phenylalanine content in
hybrid rice (
L.) have been studied through 7
rice crossed with 5
rice by using the developmental genetic models and corresponding statistical approaches for quantitative traits of triploid seeds in cereal crops. The unconditional genetic model was used to analyze the cumulative genetic effects (from flowering to a specific time) along the developmental stages, and the conditional genetic model was used to analyze the genetic effects in one specially developmental stage from one filling time to another time (
). Results showed that phenylalanine content of
hybrid rice was simultaneously controlled by the triploid endosperm effects, cytoplasm effects, diploid maternal effects and their genotype × environment interaction effects. Endosperm dominance effect, maternal additive effect and cytoplasmic effect were more important at the initial stage of rice development than endosperm additive effect and maternal dominance effect. With regard to the components of heritability, maternal and cytoplasm general heritability and their interaction heritability were higher for phenylalanine content at all 5 developmental stages. Respectively, it occupied 68.3, 92.4, 100.0, 100.0 and 78.9% among all the component of heritability. It was suggested that improving the phenylalanine content of
hybrid rice would be more efficient when selection was based on maternal plants at early generations in rice breeding program.
Authors:Y. Wang, L. Yin, G. Lv, Y. Xu, L. Xu, Y. Qi, L. Zheng, and J. Peng
In the present paper, a simple and reliable high-performance liquid chromatography-diode array detection (HPLC-DAD) method was developed both for quantitative determination and fingerprint analysis of Agrimonia pilosa Ledeb for quality control. Under the optimized HPLC conditions, seven bioactive compounds including rutin, quercetin-3-rhamnoside, luteoloside, tiliroside, apigenin, kaempferol, and agrimonolide were determined simultaneously. For fingerprint analysis, 11 common peaks were selected as the characteristic peaks to evaluate the similarities of 16 different samples collected from different origins in China. Besides, hierarchical cluster analysis (HCA) was also performed to evaluate the variation of the raw materials. This is the first report of using a simple method for quality control of A. pilosa Ledeb through multi-component determination and chromatographic fingerprint analysis to the best of our knowledge.
Authors:Z. Huang, H. Long, Y. Wei, P. Qi, Z. Yan, and Y. Zheng
The most abundant seed storage proteins of wheat are gliadins and glutenins. Gliadins, including
types, are normally monomeric proteins and account for about 50% of the gluten proteins. In this study, 55 sequences of
-gliadin genes were obtained from species of
section, the deduced B genome donors of wheat. Despite the high sequence similarities to the known
-gliadin genes, extensive variations were also found. Using the extensive sequence information deposited in database and obtained in this study, a comprehensive classification of the
-gliadin multigene families were performed based on the primary structures and phylogenic analysis. All the
-gliadin genes analyzed could be divided into 2 types, which contain 8 and 9 cysteines, respectively. Type I (with 8 cysteines) and type II (with 9 cysteines) are further classified to 7 and 4 groups, respectively, and several subgroups are also identified. The genes derived from A, B and D genomes of common wheat were clustered distinctly, indicating that there was apparent genomic specificity in
-gliadins genes. Besides the high homology between
-gliadin genes from
species and B genome of wheat, some unique groups or subgroups were also identified in
section, suggesting that it could be considered as a valuable source of
-gliadin genes. The comparison of deduced primary structures of each group and/or subgroup was conducted, from which their evolution and quality properties were also speculated.
Authors:Y. Q. Cheng, Y. X. Zhang, S. D. Qi, H. L. Chen, and X. G. Chen
1,7-Dihydroxy-3,8-dimethoxyxanthone (X1) and 1,8-dihydroxy-3,7-dimethoxyxanthone (X2) are two important xanthones of the Tibetan medicinal plant Gentianopsis paludosa (Hook. f.) Ma. They are very similar in structure, the only difference being exchange of OH and OCH3 at the 7 and 8 positions. By calculations based on the geometry of the molecules using the MM+ force field, the different distances between the hydroxyl groups of the two xanthones were obtained (4.64774 Å for X2 and 7.19412 Å for X1), therefore, the two hydroxyl groups of X1 should freely interact with more water molecules than those of X2 in aqueous solution. In other words, X2 is more hydrophobic than X1. Micellar electrokinetic capillary chromatography (MEKC) was therefore chosen for separation of the compounds. The optimum separation conditions were: 20 mm borate + 20 mm SDS (pH 9.8) as running buffer, 17.5 kV applied potential, and detection wavelength 260 nm. The two xanthones were well separated in 9.0 min, with Gaussian peak shapes. The repeatability of the MEKC method (expressed as RSD) for X1 and X2 was 0.9 and 1.1%, respectively, for migration time, and 3.1 and 1.4% for peak area. The limits of detection (S/N = 3) were 0.41 μg mL−1 for X1 and 0.82 μg mL−1 for X2. The recovery of the MEKC method for the two xanthones was also satisfactory.
Authors:S. Qiu, H. Chu, J. Zhang, Y. Qi, L. Sun, and F. Xu
The low-temperature molar heat capacities of CoPc and CoTMPP were measured by temperature modulated differential scanning
calorimetry (TMDSC) over the temperature range from 223 to 413 K for the first time. No phase transition or thermal anomaly
was observed in the experimental temperature range for CoPc. However, a structural change was found to be nonreversible for
CoTMPP in the temperature range of 368–403 K, which was further validated by the results of IR and XRD. The molar enthalpy
ΔHm and entropy ΔSm of phase transition of the CoTMPP were determined to be 3.301 kJ mol−1 and 8.596 J K−1 mol−1, respectively. The thermodynamic parameters of CoPc and CoTMPP such as entropy and enthalpy relative to reference temperature
298.15 K were derived based on the above molar heat capacity data. Moreover, the thermal stability of these two compounds
was further investigated through TG measurements. Three steps of mass loss were observed in the TG curve for CoPc and five
steps for CoTMPP.
Authors:C. Zhang, Y. Zhao, S. Feng, C. Qi, Z. Fu, F. Guo, and R. Wang
To increase the tumor uptake of Val-Gly-Gly (VGG), adenine was introduced into the peptide. N-mercaptoacetyl-VGG-adenine (MAVGG-adenine)
and MAVGG were labeled with 99mTc using a solution of SnCl2 and tartaric acid as reducing agent. Biodistribution in mice bearing the S180 tumor was measured and γ imaging was performed.
Compared with MAVGG, adenine conjugated MAVGG had higher tumor uptake and tumor to normal tissue ratios, which suggested that
the tumor uptake property of a peptide may be improved by introducing a nucleotide base. The high contrasted tumor images
of 99mTc-MAVGG-adenine also suggested its potential utility as tumor imaging agent.
Authors:Y. Zhao, C. Zhang, C. Qi, S. Feng, G. You, Z. Fu, F. Guo, and R. Wang
Two peptide ligands conjugated adenine, [9-N-(tritylmercapto acetyl diglycyl aminoethyl) adenine, Tr-MAG2-Ade] and [9-N-(tritylmercapto acetyl triglycyl aminoethyl) adenine, Tr-MAG3-Ade], are synthesized and labeled with 99mTc by directly labeling method. The stability of 99mTc-MAG2-adenine and 99mTc-MAG3-adenine in vitro is measured. The uptake radios of tumor to muscle at 3h post-injection are 5.70 and 4.92, respectively.
The biodistribution and scintigraphic imaging studies show that the two complexes have high localization in tumor and high
contrasted tumor images can be obtained, which suggest their potential utility as tumor imaging agents. But the high radioactivity
of abdomen could prevent the tumor imaging in this area.