Characterization of y-type high-molecular-weight glutenins in tetraploid species of Leymus.

Three y-type high-molecular-weight (HMW) glutenin gene open reading frames (ORFs), Chiy1, Chiy2, and Racy, were isolated and characterized from Leymus chinensis PI499516 and Leymus racemosus ssp. racemosus W623305. They shared an extra glutamine in the N-terminal and LAAQLPAMCRL peptides in the C-terminal with x-type HMW glutenins but had different N-terminal lengths. Like other y-type HMW glutenins, Chiy2 and Racy had 104 (or 105) amino acid (aa) residues at the N-terminal and started with EGEASR, whereas Chiy1 had 99 aa in this domain and started with QLQCER because of the deletion of EGEASR. Five other y-type glutenins, including those from Elymus ciliaris, Pseudoroegneria libanotica, and Leymus mollis, were similar to Chiy1. The ORF of Chiy2 was probably not expressed. The ORFs of both Chiy1 and Racy were expressed in bacteria. The maximum likelihood phylogenic tree based on the signal peptide and N-terminal and C-terminal aa residues revealed two clades of y-type HMW glutenins in Triticeae; the first contained Ay, By, Cy, Dy, Eey, Gy, Ky, Ry, Tay, and Uy, while the second clade contained the remaining y types, including those from Leymus. Within the second clade, HMW glutenins lacking the EGEASR peptide formed a subclade. These y-type HMW glutenins in Leymus could not be targeted to the Xm or Ns genome.

High-intensity focused ultrasound selective annealing induced patterned and gradient crystallization behavior of polymer.

High-intensity focused ultrasound (HIFU) was developed as a spatial selective annealing method to control the crystallization behavior and performance of polymer using amorphous polyethylene terephthalate (PET) as an example for demonstration. The spatial crystallization and morphological details of HIFU induced crystallization areas at the lamellar level and spherulite scale were studied by Micro-Focus hard X-ray diffraction, small angle X-ray scattering and optical microscopy. According to the distribution of crystallinity of PET, we can indirectly detect the history of thermal distribution of the ultrasonic focal point, which is hard to obtain by other methods. The crystallinity and the area of the crystalline region of PET sample increased with ultrasound power or irradiation time. Different from common crystalline structure of polymer materials, HIFU induced crystallinity of PET has a significant gradient distribution. The gradient crystal structure leads to a better mechanical performances, which can realize the good balance between toughness and strength. Ultrasound annealing, as a complement and development of the traditional annealing technology, has the characteristics of high efficient and spatial selectivity, showing great application prospect in post processing field.

HIFU induced particles redistribution in polymer matrix via synchrotron radiation X-ray microtomography.

High-intensity Focused Ultrasound (HIFU) was used to stimulate the embedded copper sulfate (CuSO4) particles to release from the crosslinked poly (methyl methacrylate-co-butyl acrylate) copolymer solid matrix. In order to better understand the ultrasound release mechanism for drug/polymer delivery systems, the synchrotron radiation X-ray computed microtomography (SR-CT) was used to non-destructively investigate the structure of drug/polymer delivery systems after different HIFU treatment time. For the first time, we clearly demonstrate that ultrasonic waves can overcome the constraints of the polymer chain and drive the filler to move from the strong region to the weak region in the solid polymer matrix, thus resulting in a change in distribution of the filler in solid polymers. This result also demonstrates that SR-CT is a powerful technique which can be used to quantitatively study the 3D structure of fillers/polymers composite as it can take a broader and overall view than the conventional localized two-dimensional analysis method such as SEM, TEM.