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  • Author or Editor: Y. Zheng x
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Abstract  

Hair samples of mildly mentally retarded (LR), moderately mentally retarded (MR), severely mentally retarded (SR) and normal children were collected and measured, using neutron activation analysis and X-ray fluorescence to determine the concentrations of Al, Sb, As, Ca, Cu, I, Fe, Pb, Mg, Mn, Hg, K, Sr, S, V and Zn. The groups of children were of ages between 5 and 13. Difference in the mean concentration of each element between groups was tested by Student"s t-test. No trend, either decreasing or increasing, has been established as the degree of severity increased from normal to SR children, except for the case of Cu. The present work may shed some light in the interpretation of findings on the effects of trace elements on neurobehavioral functions.

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Abstract  

Epoxidized natural rubbers (ENRs) with different extents of epoxidation (B) were prepared under various reaction conditions. The effects of the amount of H2O2 and the reaction time on B are discussed. The glass transition temperature T g, the thermal degradation temperature and the activation energy of thermal degradation of the ENRs increase with B. The results indicate that the thermal stability of the ENRs increases with B.

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Abstract  

The isotope fractionation of potassium in an aqueous (KOH)/amalgam system has been studied. Two types of isotope effects with opposite isotope enrichment directions were observed in the electrolysis of potassium from the aqueous into the amalgam phase under constant electrolytic potentials. It was found that the first isotope effect causing the light isotope enriched in the amalgam is related to the kinetic process of the mass transfer through the aqueous/amalgam interface, while the second one leading to the enrichment of the heavy isotope in the amalgam phase is produced by the isotope-exchange equilibrium. The temperature dependence of the equilibrium isotope effect was also investigated using single-stage and multi-stage techniques. It was observed that the equilibrium isotope effect increases as the temperature increases in the range of 293-371 K. An empirical equation was used to fit the variations of the isotope effects with temperature for potassium together with the other alkaline and alkaline earth metals studied in the same system. The origin of the equilibrium isotope fractionation in the electron-exchange system was discussed. Furthermore, the mass dependence of the separation coefficients of the alkaline and alkaline earth metals observed in aqueous/amalgam and ion-exchange systems were compared. At 293 K the equilibrium isotope separation coefficient for the 39K/41K isotopes in the amalgam system was determined as (5.6±0.6).10-3.

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Abstract  

The trace element profiles of the scalp hair of NPC patients, aged between 30 and 69, were measured using neutron activation analysis and compared with those of normal healthy people within the same age bracket. The washing method of using detergent and washing powder was found to be comparable to that of using ether. Difference in the mean concentration of each element in the two groups was tested by Student's t-test. A significantly lower value of strontium (Sr) and significantly higher values of arsenic (As), iron (Fe) and vanadium (V) were found in the hair of NPC patients. The relative values of As and Fe found were consistent with the results of other findings on NPC patients, using different measuring methods. The V content in the hair of NPC patients was three times that of healthy people.

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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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A novel HMW-GS of Dx5** with slightly faster migration rate than that of Dx5, was found in a Tibet bread wheat landrace using SDS-PAGE. Moreover, Dx5** is the subunit with the fastest migration rate in Glu-Dx locus. The gene for this subunit was isolated and its sequence was obtained in the present study. This gene was very similar to Dx5 both in nucleotide and deduced amino acid sequence. At the nucleotide sequence level, Dx5** different from Dx5 by the deletion of a 27 bp fragment and two nucleotide replacements at position 353(G/C) and 692(C/G), respectively. At the amino acid sequence level, Dx5** different from Dx5 by the deletion of a hexaploid (LGQGQQ) and a tripeptide (GQQ) repetitive motif and two amino acid replacements at position 118(C/S) and 231(A/G), respectively. These results suggested that the Dx5** was a derivation of Dx5 and was formed by replication slippage. Moreover, the specific cysteine (C) located at the beginning of the repetitive domain of Dx5, which proved to be critical for the end-use quality of wheat flours, was replaced by serine (S) in Dx5**.

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Changes in microbial population, pH, sugar, organic acid, anthocyanins, total soluble phenolics, and anti-glucosidase contents were measured during fermentation of mulberry juice at 30 °C by probiotic Leuconostoc mesenteroides showing rapid growth after an approximately 1-day lag phase and reaching a maximum of 8.6 log CFU ml−1 after 4 d. During the rapid growth phase, the main mulberry juice sugars, glucose and fructose, were largely consumed, and the acidic metabolites, lactic acid and acetic acid, were produced accordingly. A slow decrease in the concentration of the main organic acid, citric acid, was also observed during fermentation. After 4 d fermentation, anthocyanin content showed a 44.4% reduction, but the total amount of soluble phenolics and α-glucosidase inhibitory activity showed no significant changes (P>0.05). This suggests that L. mesenteroides fermentation of mulberry juice is a good strategy to enhance its probiotic value and to decrease the sugar content without changing the anti-glucosidase activity, which is required to reduce postprandial rise in blood glucose.

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ERECTA is an ancient family of leucine-rich repeat receptor-like kinases (RLKs) that coordinate growth and development of plant. TaERECTA, one copy of the ERECTA homologs in wheat, was isolated from bread wheat Chinese Spring. The Ser/Thr kinase of TaERECTA was expressed in E. coli after IPTG induction and confirmed by immunoblot. TaERECTA showed higher expression in younger organs with rapid development, as well as great expression in younger spikes at booting stage. Under exogenous application of gibberellin (GA3) and abscisic acid (ABA), and Mg2+ stress, the expression of TaERECTA was largely suppressed, whereas under exogenous application of indole acetic acid (IAA) and brassinolide (BR), and dehydration stress, its expression was initially suppressed and then up-regulated. Natural variation was apparent in the relative expression of TaERECTA among 9 different bread wheat lines, and its expression level was negatively correlated with the stomatal density. These results suggested that TaERECTA could be exploitable for manipulating agronomical traits important through regulating stomata density, with potential implication for bread wheat improvement.

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Summary

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.

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