Structure, optical simulation and thermal stability of the HfB2-based high-temperature solar selective absorbing coatings.

Transition metal borides are a kind of potential materials for high-temperature solar thermal applications. In this work, a novel SS/HfB2/Al2O3 tandem absorber was prepared, which exhibited high solar spectrum selectivity (α/ε) of 0.920/0.109. The optical constants of the coating were obtained using spectroscopic ellipsometry, and the dispersion model of the HfB2 layer was modeled with the Tauc-Lorentz dispersion formula. In addition, the reflectance spectrum simulated by the CODE software corroborated well with the experimental results. The thermal stability test indicated that the HfB2/Al2O3 solar absorber coating was thermally stable in vacuum at 600 °C for 2 h. When extending the annealing time to 100 h, the coating could maintain high spectral selectivity after aging at 500 °C irrespective of whether in air or vacuum. All these results indicate that the coating has good solar selectivity and is a promising candidate for high-temperature solar thermal applications.

Host-induced gene silencing of an essential chitin synthase gene confers durable resistance to Fusarium head blight and seedling blight in wheat.

Fusarium head blight (FHB) and Fusarium seedling blight (FSB) of wheat, caused by Fusarium pathogens, are devastating diseases worldwide. We report the expression of RNA interference (RNAi) sequences derived from an essential Fusarium graminearum (Fg) virulence gene, chitin synthase (Chs) 3b, as a method to enhance resistance of wheat plants to fungal pathogens. Deletion of Chs3b was lethal to Fg; disruption of the other Chs gene family members generated knockout mutants with diverse impacts on Fg. Comparative expression analyses revealed that among the Chs gene family members, Chs3b had the highest expression levels during Fg colonization of wheat. Three hairpin RNAi constructs corresponding to the different regions of Chs3b were found to silence Chs3b in transgenic Fg strains. Co-expression of these three RNAi constructs in two independent elite wheat cultivar transgenic lines conferred high levels of stable, consistent resistance (combined type I and II resistance) to both FHB and FSB throughout the T3 to T5 generations. Confocal microscopy revealed profoundly restricted mycelia in Fg-infected transgenic wheat plants. Presence of the three specific short interfering RNAs in transgenic wheat plants was confirmed by Northern blotting, and these RNAs efficiently down-regulated Chs3b in the colonizing Fusarium pathogens on wheat seedlings and spikes. Our results demonstrate that host-induced gene silencing of an essential fungal chitin synthase gene is an effective strategy for enhancing resistance in crop plants under field test conditions.

[Mapping of the loss of heterozygosity for chromosome 1 pter-36.21 in keloid].

OBJECTIVE: The aim of this study was to investigate the loss of heterozygosity (LOH) on chromosome 1 pter-36.21 of keloid in order to locate the deletion areas probably harboring scar suppressor genes. METHODS: Using polymerase chain reaction ( PCR )-denaturing polyacrylamide gel electrophoresis, 25 samples of keloid tissues and peripheral blood were analyzed. RESULTS: 15 out of 25 samples of keloid tissues exhibited LOH in at least one microsatellite locus. There were deletions at more than one locus of one keloid tissue. No MSI was found. The frequency of LOH was remarkably higher in the keloid tissues (n = 25, 15, 60%) than in the normal control samples (n = 25, 1, 4%). The frequency of LOH in D1S243, D1S468, D1S507 and D1S199 was as following: (n= 25, 7, 28%), (n =25, 10, 40%), (n = 25, 13, 52%) and (n= 25, 3, 12%). The frequency of LOH in D1S243, D1S468, D1S507 were statistically significant. CONCLUSION: The most common LOH occurred at D1S243-D1S468-D1S507 might imply the existence of potential tumor suppressor gene of a subset of keloid , while MSI on 1 pter-36.21 may not a crucial event.