Mechanical properties and surface characteristics of SiC fibers irradiated by swift heavy ions

SiC fibers were irradiated by 414.4-MeV^(112)Sn^(27.3+)ions to different fluences(5.0×10^(12),6.0×10^(13),1.6×10^(14),and 1.92×10^(15)ions/cm^(2)).^(112)Sn^(27.3+)deposited its energy mainly via electron energy loss and passed through the SiC fiber.Then,the mechanical properties and surface characteristics of fibers were studied using a specific single filament tensile test and field emission scanning electron microscopy.Results revealed that the carbon concentration on the fiber surface increased while the silicon concentration decreased.Moreover,the addition of oxygen was found to correlate with an increase in ion fluence.Meanwhile,the fiber surface morphology of the least fluence(5.0×10^(12)ions/cm^(2))irradiated specimen displayed no obvious changes and its diameter was slightly reduced.With successive increases of ion fluence,large grains/bubbles on the fiber surface first appeared and then disappeared,and the diameter of fibers evidently increased.Moreover,at the highest fluence(1.92×10^(15)Sn ions/cm^(2))irradiated specimen,some fibers were brittle fractured.As a result,the mean tensile strength and the average elastic modulus of the fibers generally decreased with respect to the ion fluence.The degradation mechanisms of mechanical properties of SiC fibers under irradiation are discussed in detail.

The different interactions of Colletotrichum gloeosporioides with two strawberry varieties and the involvement of salicylic acid

The disease symptoms recognized as‘Anthracnose’are caused by Colletotrichum spp.and lead to large-scale strawberry(Fragaria×ananassa Duchesne)losses worldwide in terms of both quality and production.Little is known regarding the mechanisms underlying the genetic variations in the strawberry–Colletotrichum spp.interaction.In this work,Colletotrichum gloeosporioides(C.gloeosporioides)infection was characterized in two varieties exhibiting different susceptibilities,and the involvement of salicylic acid(SA)was examined.Light microscopic observation showed that C.gloeosporioides conidia germinated earlier and faster on the leaf surface of the susceptible cultivar compared with the less-susceptible cultivar.Several PR genes were differentially expressed,with higher-amplitude changes observed in the less-susceptible cultivar.The less-susceptible cultivar contained a higher level of basal SA,and the SA levels increased rapidly upon infection,followed by a sharp decrease before the necrotrophic phase.External SA pretreatment reduced susceptibility and elevated the internal SA levels in both varieties,which were sharply reduced in the susceptible cultivar upon inoculation.The less-susceptible cultivar also displayed a more sensitive and marked increase in the transcripts of NB-LRR genes to C.gloeosporioides,and SA pretreatment differentially induced transcript accumulation in the two varieties during infection.Furthermore,SA directly inhibited the germination of C.gloeosporioides conidia;NB-LRR transcript accumulation in response to SA pretreatment was both dose-and cultivar-dependent.The results demonstrate that the less-susceptible cultivar showed reduced conidia germination.The contribution of SA might involve microbial isolate-specific sensitivity to SA,cultivar/tissue-specific SA homeostasis and signaling,and the sensitivity of R genes and the related defense network to SA and pathogens.

Damage produced on GaN surface by highly charged Krq+irradiation

Surface morphology, compositions, microstructure and optical properties of GaN film irradiated by highly charged Kr^(q+)(q = 23, 15, 11) in two geometries to a fluence of 1×10^(15)kr^(q+)/cm^2 were studied using AFM,XPS, PL, Raman scattering and UV–visible spectroscopy.The AFM observation shows that the irradiated GaN area is a swollen terrace. The swelling rate increased with the charge state(potential energy). For the same charge state,the swelling rate of tilted incidence was greater than that for normal incidence. The XPS measurements reveal that N deficiency, Ga enrichment and Ga–O and Ga dangling bonds generated on the irradiated GaN surface increased with the charge state, and more N was lost for normal incidence than that for tilted incidence. The UV–Vis results show that the transmittance decreased with increasing charge state. For the same charge state, the transmittance for tilted incidence is higher than that for normal incidence.The PL spectra present that, with increasing charge state,the YL band intensity decreased, with a blueshift in its peak position; while the NBE peak intensity increased firstand then reduced, and a blue luminescence band appeared.A rapid quenching of both the YL and the NEB for normal incidence was observed. Raman spectra display that screw dislocations perhaps were produced near the surface for normal incidence.

Identification and characterization of microRNAs in the white-backed planthopper, Sogatella furcifera

MicroRNAs （miRNAs） are a novel class of small, non-coding endogenous RNAs that play critical regulatory roles in many metabolic activities in eukaryotes. Reports of the identification of miRNAs in Sogatella furcifera （white-backed planthopper）, the insect that acts as the only confirmed vector of the southern rice black-streaked dwarf virus （SRBSDV）, are limited. In this study, a total of 382 miRNAs were identified in S. furcifera, including 106 conserved and 276 novel miRNAs, using high-throughput sequencing based on two small RNA libraries from viruliferous and non-viruliferous S. furcifera, and these miRNAs belonged to 52 conserved miRNA families and 58 S. furcifera-specific families, respectively. Comparison with miRNAs from 26 insect species and five other species in miRBase showed that more than half of the conserved miRNA families are highly conserved in Hexapoda, while other miRNAs are only conserved in non- dipterans. Furthermore, 4 117 target genes predicted for the 382 identified miRNAs could be categorized into 45 functional groups annotated by Gene Ontology. Compared with non-viruliferous cells, eight up-regulated miRNAs and four down-regulated miRNAs were identified in cells inoculated with SRBSDV, among which miR-14 and miR-n98a may be involved in the immune response to SRBSDV infection. Analyses of the identified miRNAs will provide insights into the roles of these miRNAs in the regulation and expression of genes involved in the metabolism, development and viral infection of S. furciJbra.

BHONEM:Binary High-Order Network Embedding Methods for Net worked-Guarantee Loans

Networked-guarantee loans may cause systemic risk related concern for the government and banks in China.The prediction of the default of enterprise loans is a typical machine learning based classification problem, and the networked guarantee makes this problem very difficult to solve. As we know, a complex network is usually stored and represented by an adjacency matrix. It is a high-dimensional and sparse matrix, whereas machine-learning methods usually need lowdimensional dense feature representations. Therefore, in this paper, we propose a binary higher-order network embedding method to learn the low-dimensional representations of a guarantee network. We first set vertices of this heterogeneous economic network by binary roles (guarantor and guarantee), and then define high-order adjacent measures based on their roles and economic domain knowledge. Afterwards, we design a penalty parameter in the objective function to balance the importance of network structure and adjacency. We optimize it by negative sampling based gradient descent algorithms,which solve the limitation of stochastic gradient descent on weighted edges without compromising efficiency. Finally, we test our proposed method on three real-world network datasets. The result shows that this method outperforms other start-of-the-art algorithms for both classification accuracy and robustness, especially in a guarantee network.