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The wheat storage proteins, especially the high molecular weight glutenin subunits (HMW-GS), play important roles in the determination of flour processing and bread-making quality. Compared with the traditional SDS-PAGE method, reversed-phase high-performance liquid chromatography (RP-HPLC) was shown to have many advantages for the separation and characterization of HMW-GS because of its high resolving power, repeatability and automation. In this work, HMW-GS from bread and tetraploid wheats were separated and characterized by RP-HPLC. The elution time ranking of different HMW-GS was: 1Ax > 1Bx > 1Dx > 1By > 1Dy. Several subunit pairs associated with good quality properties and those with similar mobilities on SDS-PAGE, such as 1Bx7 and 1Bx7*, 1By8 and 1By8*, 1Dx2 and 1Ax2*, 1Bx6 and 1Bx6.1, were well separated and readily identified through RP-HPLC. However, other subunit pairs, such as 1Dy10 — 1Dy12, 1Dx5 — 1By18 and 1Dx2 — 1By16, could not be adequately separated and identified by RP-HPLC, whereas they displayed different mobilities on SDS-PAGE gels. Because 1Dx5 and 1Dx2 showed different hydrophobicities, RP-HPLC could distinguish 1Dx5 + 1Dy10 and 1Dx2 + 1Dy12. A comparative analysis between RP-HPLC and SDS-PAGE showed that a combination of both methods provided more effective identification of HMW-GS in wheat quality improvement and germplasm screening.

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Fructose-bisphosphate aldolase (FBA, EC 4.1.2.13) catalyzes an aldol cleavage of fructose-1, 6-bisphosphate to dihydroxyacetone-phosphate and glyceraldehyde 3-phosphate and a reversible aldol condensation. Three candidate genes with 1077bp coding for fructose-bisphosphate aldolase were cloned and sequenced in wheat, barley and rye. These genes could encode 358 amino acid residues. Sequence analysis indicated that wheat, barley and rye FBA genes were conserved with high identity (94.13%), while maize sequence had a 9bp deletion near the 3’ terminal. According to the alignment of 75 amino acid sequences, conserved domains of the FBAs were detected. These conserved domains might be the important functional sites of the FBAs. The cytoplasmic FBAs of wheat, barley and rye were clustered together, and the cluster was close to maize and rice FBAs. Nine peptides of the FBAs and the last amino acid Tyr (necessary for preference for fructose 1,6-bisphosphate over fructose 1-phosphate) were most conserved in plants, animals and algae. Current findings suggested that the FBAs could be divided into three main subgroups: plant cytoplasmic FBA, plant chloroplastic FBA and animal FBA. These results also indicated that the active and binding sites of FBAs had rare variations during the long-term evolution.

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Two new y-type HMW-GSs in Ae. tauschii , 1Dy12.1* t and 1Dy12.2 t with the mobility order of 1Dy12.2 t > 1Dy12.1* t > 1Dy12.1 t >1Dy12, were identified by both SDS-PAGE and MALDI-TOF-MS. Molecular cloning and sequencing showed that the genes encoding subunits 1Dy12.1* t and 1Dy12.2 t had identical nucleotide acid sequences with 1,947 bp encoding a mature protein of 627 residues. Their deduced molecular weights were 67,347.6 Da, satisfactorily corresponding to that of 1Dy12.2 t subunit determined by MALDI-TOF-MS (67,015.7 Da), but was significantly smaller than that of the the 1Dy12.1* t subunit (68,577.1 Da). Both subunits showed high similarities to 1Dy10, suggesting that they could have a positive effect on bread-making quality. Interestingly, the expressed protein of the cloned ORF from accessions TD87 and TD130 in E. coli co-migrated with subunit 1Dy12.2 t , but moved slightly faster than 1Dy12.1* t on SDS-PAGE. The expressed protein in transgenic tobacco seeds, however, had the same mobility as the 1Dy12.1* t subunit, as confirmed by both SDS-PAGE and Western blotting. Although direct evidence of phosphoprotein could not be obtained by specific staining method, certain types of post-translational modifications (PTMs) of the 1Dy12.1* t subunit could not be excluded. We believe PTMs might be responsible for the molecular weight difference between the subunits 1Dy12.1* t and 1Dy12.2 t .

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Abstract

The thermal pyrolysis of carboxymethyl hydroxypropyl sesbania gum and hydroxypropyl sesbania gum in air and nitrogen atmospheres were studied in order to establish the thermal stability of carboxymethyl hydroxypropyl sesbania gum. The results indicate that the stability of carboxymethyl hydroxypropyl sesbania gum against pyrolysis is higher than that of hydroxypropyl sesbania gum. The main state of carboxymethyl hydroxypropyl sesbania gum and hydroxypropyl sesbania gum can be assigned as random noncrystalline.

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Abstract

The thermal decomposition of a new antibiotic agent, cefuroxime lysine, was investigated by thermogravimetry analysis/derivative thermogravimetry and differential scanning calorimetry (DSC) methods in anoxic and oxidative environments. The influence of heating rates (including 5, 10, 15, and 20 °C/min) on the thermal behavior of cefuroxime lysine was revealed. By the methods of Kissinger and Flynn–Wall–Ozawa, the thermal kinetic parameters of activation energy and pre-exponential factor for the exothermic processes under non-isothermal conditions were calculated using the analysis of corresponding DSC curves.

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Journal of Thermal Analysis and Calorimetry
Authors:
Hou-yin Zhao
,
Yan Cao
,
Zhi-zhong Kang
,
Yau-bang Wang
, and
Wei-ping Pan

Abstract

Chemical looping combustion (CLC) is a novel combustion technology with the capability for segregation of exhaust products (i.e., carbon dioxide/H2O or N2/O2). The combustion is performed in two interconnected reactors with a solid oxygen carrier circulating between them, transferring oxygen from the air to the fuel. The feasibility of a successful CLC system depends on the selection of an appropriate oxygen carrier. Cu-based oxygen carriers are good oxygen carriers due to high reactivity. However, it faces low melting point, agglomeration problems in fluidized bed. In this study, a circular reduction–oxidation reaction simulated to the cyclic operation of the Cu-based oxygen carrier was conducted on the thermogravimetric analyzer (TG). The thermal behaviors of the potential Cu-based oxygen carrier were investigated by using an X-ray diffraction (XRD), scanning electron microscope (SEM), and surface analyzer. Multiple TG results show that the weight loss was 3.4%, indicating that the loading CuO amount was 17%. Moreover, the weight loss and weight gain was equal during 73 redox cycles, suggesting the good thermal stability of the oxygen carrier. The conversion rate of reduction and oxidation for each redox cycle remained constant even after 73 redox cycles. XRD results show the new phase formation of CuAl2O4 during redox cycles, which promotes the thermal stabilization of the oxygen carrier. The surface area of the oxygen carrier decreased from 105 to 13 m2 g−1 after 73 redox cycles and the particle size distribution shifted from 5–15 nm to 15–30 nm, suggesting that the micorpores were blocked or collapsed. However, the reactivity of the oxygen carrier didn't decrease. SEM results show that CuO was evenly distributed on the surface of Al2O3 after 73 redox cycles. Overall, these results suggested that the Cu-based oxygen carrier was ready for fluidized bed tests.

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Abstract  

The influence of the concentration of sodium oleate (NaOL), alcohol and the nature of the internal water phase on the water content of microemulsion was studied. The effect of the concentration of NaOL, sodium stearate, alcohol, salting-out agent, Alamine 336 added and of the contact time, volume ratio of the aqueous to microemulsion (R) and temperature on the extraction yield of samarium was investigated. The result shows that the extraction of samarium is effective under well-defined conditions utilizing WinsorII microemulsion systems.

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Abstract  

An intelligent hydrogel with both pH and temperature sensitivity was obtained by grafting acrylic acid and dimethylaminoethylmethacrylate onto preirradiated polypropylene (PP) film by two-step reactions. The effect of first and second reactions on the degree of grafting was studied. The grafted sample films were checked by Fourier transform infrared spectrophotometry in the attenuated total reflectance mode. The morphology of the PP samples was observed by scanning electron microscope in different conditions before and after grafting, respectively.

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Abstract  

The bentonite/iron oxide magnetic composites were prepared by co-precipitation method, and characterized by Fourier transform infrared spectroscopy, X-ray powder diffraction and scanning electron microscope. The prepared bentonite/iron oxide magnetic composites were used as a sorbent for the removal of Co(II) ions from radioactive wastewater. The results demonstrated that the sorption of Co(II) was strongly dependent on pH and ionic strength at low pH values. The sorption of Co(II) was dominated by outer-sphere surface complexation or ion exchange at low pH whereas inner-sphere surface complexation was the main sorption mechanism at high pH. The presence of iron oxide in the composites also contributes to the sorption of Co(II) ions on the magnetic composites. The experimental data were well described by Langmuir model. The thermodynamic parameters (∆G °, ∆S °, ∆H °) calculated from the temperature-dependent sorption isotherms indicated that the sorption of Co(II) on bentonite/iron oxide magnetic composites was an endothermic and spontaneous processes.

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Patrinia scabiosaefolia Fisch. (PSF), a well-known traditional Chinese medicine, has been demonstrated to show therapeutic effects on inflammatory bowel disease. In this study, a rapid and sensitive method using ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UPLC/Q-TOF-MS) was developed for identification of the major constituents in PSF. The separation analysis was performed on Waters Acquity UPLC system, and the accurate mass of molecules and their fragment ions were determined by Q-TOF-MS. Thirty-one constituents, including triterpenoids, iridoids, flavonoids, and organic acids were detected and tentatively deduced on the basis of their element compositions, tandem mass spectrometry (MS/MS) data, and relevant literatures. Twelve constituents were discovered for the first time in PSF. The results demonstrated that hederagenin-type and oleanolic acid-type saponins were the main constituents of PSF. Our work provides a certain foundation for further quantitation of major chemical constituents and in vivo pharmacokinetic studies of PSF. Moreover, the analytical approach developed herein has proven to be generally applicable for profiling the chemical constituents in traditional Chinese medicines (TCMs) and other complicated mixtures.

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