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  • Author or Editor: G. J. Yang x
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Quantitative trait loci (QTL) for 11 morphometric body measurements of the hybrids of silver (Hypophthalmichthys molitrix) and bighead carp (H. nobilis) including body weight (BW), standard length (SL), body depth (BD), body thickness (BT), head length (HL), head depth (HD), length of ventral keel (LVK), length of pectoral fin (Lpec), length of pelvic fin (Lpel), length of caudal fin (Lcau) and space between pectoral and pelvic fins (SPP) were located on the sex average microsatellite linkage map constructed using the hybrids of a female bighead and a male silver carp, on which 15 microsatellites were newly mapped. One locus was found to be responsible for BW, LV K and SPP, respectively. As many as 6 loci were found to be responsible for HD. The variances of remaining traits were partitioned by different numbers of loci varying between 2 and 5. The variance explained each locus ranged from 9.1% to 23.8% of the total. The variance explained by all loci responsible for each measurement ranged from 17.7% to 75.1%. It was noted that multiple measurements were mapped on the same locus. For example, a region bounded by Hym435 and Hym145 was found to be responsible for all the measurements analyzed.

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A simple and sensitive method of high-performance liquid chromatography with fluorescence detection (HPLC-FLD) was developed for the determination of icariin in capsules by precolumn chelation with aluminum. In order to obtain a stable fluorescence signal, the reaction conditions of the fluorescent chelation complex between icariin and aluminum were investigated in detail. Chromatography was carried out on an Agilent Zorbax Extend C18 column (150 mm × 4.6 mm, 5.0 μm) using methanol as mobile phase at a flow rate of 1.0 mL min−1. The excitation and emission wavelengths were set at 430 and 480 nm, respectively. At optimum conditions, the calibration curve was linear in the concentration range from 0.010 to 100.0 μg mL−1 with the limit of detection of 3.5 ng mL−1 (S/N = 3). A comprehensive method was validated for precision and accuracy. The method described here has been successfully applied for the determination of the icariin content in a capsule with satisfactory results.

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Abstract  

Monochromatic MeV-energy neutron source for secondary reaction was developed utilizing tritium embedded titanium (Ti-3H) thin film via 3H(p,n)3He reaction. We have measured the neutron energies and the energy spread by resonance reactions of 12C(n,tot) and 28Si(n,tot). The available energy was within the range from 0.6 to 2.6 MeV. Energy spread was 1.6% at energy of 2.077 MeV. The flux in the beam direction was determined to be 3.76·107 n/s/sr by irradiating 197Au by about 2 MeV neutrons. This source was shown to be useful for measurements of nuclear data by measuring the total cross sections of neutrons on Fe and comparing these data to the data of ENDF-6.

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Supramolecular 2,3- and 2,5-pyridinedicarboxylate (PDC) intercalated ZnAl-layered double hydroxides (2,3- and 2,5-PDC–ZnAl–LDHs) have been prepared by ion exchange method. The structure and composition of the intercalated materials have been studied by X-ray diffraction (XRD) and inductively coupled plasma emission spectroscopy (ICP). The study indicates that the 2,3-PDC and 2,5-PDC anions are accommodated as interdigitated bilayer and monolayer arrangement respectively between the sheets of LDHs. Furthermore, their thermal decomposition processes were studied by the use of in situ high temperature X-ray diffraction (HT-XRD), and the combined technique of thermogravimetry-differential thermal analysis-mass spectrometry (TG-DTA-MS) under N2 atmosphere. Based on the comparison study on the temperatures of both decarboxylation and complete decomposition of interlayer PDC, it can be concluded that 2,5-PDC–ZnAl–LDHs has higher thermal stability than that of 2,3-PDC–ZnAl–LDHs.

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Poly(AN—co—St) (PAS) and poly(AN—St—MMA)(PASM) were synthetized by emulsion polymerisation. The glass transition temperatures (T g) of the copolymers and the relationship between T g and the components of the copolymers were investigated by differential scanning calorimetry. The results show that T g for the AN—St bipolymers has apeak value in the range 115–118°C at a content of 50 mass% St. When methyl methacrylate was added, the T g of the terpolymer was decreased by about 2–6°C.The thermostability and the activation energy E of degradation were determined by thermogravimetric analysis.

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Abstract  

Positron annihilation induced Auger Electron Spectroscopy (PAES), makes use a beam of low energy positrons to excite Auger transitions by annihilating core electrons. This novel mechanism provides PAES with a number of unique features which distinguishes it from other methods of surface analysis. In PAES the very large collisionally induced secondary electron background which is present under the low energy Auger peaks using conventional tecniques can be eliminated by using a positron beam whose energy is below the range of Auger electron energies. In addition, PAES is more surface selective than conventional Auger Spectroscopy because the PAES signal originates almost exclusively from the topmost atomic layer due to the fact that the positrons annihilating with the core electrons are trapped in an image correlation well just outside the surface. In this paper, recent applications of Positron Annihilation Induced Auger Electron Spectroscopy (PAES) to the study of surface structure and surface chemistry will be discussed including studies of the growth, alloying and inter-diffusion of ultrathin layers of metals, metals on semiconductors, and semiconductors on semiconductors. In addition, the possibilities for future application of PAES to the study of catalysis and surface chemistry will be outlined.

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Wheat yellow rust resistance gene Yr17 was originated from the wheat-Aegilops ventricosa introgression, and still effective on the adult plant in Southern China. The previous studies located the gene Yr17 on the translocation of 2NS-2AS using the molecular and cytological markers. In the present study, we screened new PCR-based markers to map the gene Yr17 region from the investigation of a segregating 120 F2 population. All markers including four EST-PCR markers, a SCAR (sequence characterized amplified region) and a PLUG (PCR based landmark unique gene) marker specific to Yr17 gene were mapped on the chromosome 2AS, and located on the chromosomal deletion bin 2AS5-0.8–1.00 region. Based on the wheat-rice collinearity, we found that the sequences of the Yr17 gene linked markers were comparatively matched at rice chromosome 4 and chromosome 7. However, the identified closely linked genomic sequence of Yr17 gene is most likely collinear with genomic region of rice chromosome 4. The newly produced PCR based markers closely linked to Yr17 gene will be useful for the marker-assisted selection in wheat breeding for rust resistance.

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Global rice supplies have been found contaminated with unapproved varieties of genetically modified (GM) rice in recent years, which has led to product recalls in several of countries. Faster and more effective detection of GM contamination can prevent adulterated food, feed and seed from being consumed and grown, minimize the potential environmental, health or economic damage. In this study, a simple, reliable and cost-effective multiplex polymerase chain reaction (PCR) assay for identifying genetic modifications of TT51-1, Kemingdao1 (KMD1) and Kefeng6 (KF6) rice was developed by using the event-specific fragment. The limit of detection (LOD) for each event in the multiplex PCR is approximately 0.1%. Developed multiplex PCR assays can provide a rapid and simultaneous detection of GM rice.

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The effects of sowing date, nitrogen application level and timing on barley protein components and malt quality were investigated. There was a significant difference in total protein and its protein fractions among the four barley genotypes. The protein component was changeable over the different growing conditions, and the extent of change varied with protein fraction and genotype. Marked variation in malt quality over the different environments (sowing date, N fertilizer rate and applying time) was also observed. Increased N fertilizer application increased diastatic power (DP) value, but reduced malt extract. Grain protein content was significantly and positively correlated with albumin, globulin and hordein, but was not correlated with glutelin. However, glutelin was significantly related to other malt quality parameters.

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Three wheat varieties of Atlas66 (Al-tolerant genotype), EM12 (a major elite cultivar in China) and Scout66 (Al-sensitive genotype) were used to investigate their potential mechanisms of Al toxicity. Al concentrations of 50, 75, 100 μmol l −1 were used and the inhibition on root elongation between Scout66 and EM12 is significantly higher than that of Al-tolerant Atlas66, which is negative correlated to the Al absorption in root apices. Organic acids secretion was checked 24 h after Al stress and only malate was detected in Atlas66, but none of the organic acids were detected in the others, suggesting that secretion of malate in root is a major mechanism of Al resistance in Al-tolerant wheat genotype. The root cell ultrastructure showed less damage in Atlas66 than that in Scout66 and EM12 under Al stress by transmission electron microscopy (TEM) technique. Tissue culture was carried out and the callus induction frequencies were all decreased on the media containing Al. The decrease of callus induction frequencies was less in Atlas66 than that in the others. It is concluded that Al damages the cell ultrastructure, resulting in the inhibition of acids secretion and cell division, which implies that the damage of cell ultrastructure is probably the key factor in Al inhibition of root growth.

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