Pan-genome analysis of the Burkholderia gladioli PV. Cocovenenans reveal the extent of variation in the toxigenic gene cluster.

Burkholderia gladioli has been reported as the pathogen responsible for cases of foodborne illness in many countries. The poisonous bongkrekic acid (BA) produced by B. gladioli was linked to a gene cluster absent in non-pathogenic strains. The whole genome sequence of eight bacteria strains, which were screened from the collected 175 raw food and environmental samples, were assembled and analyzed to detect a significant association of 19 protein-coding genes with the pathogenic status. Except for the common BA synthesis-related gene, several other genes, including the toxin-antitoxin genes, were also absent in the non-pathogenic strains. The bacteria strains with the BA gene cluster were found to form a single cluster in the analysis of all B. gladioli genome assemblies for the variants in the gene cluster. Divergence of this cluster was detected in the analysis for both the flanking sequences and those of the whole genome level, which indicates its complex origin. Genome recombination was found to cause a precise sequence deletion in the gene cluster region, which was found to be predominant in the non-pathogenic strains indicating the possible effect of horizontal gene transfer. Our study provided new information and resources for understanding the evolution and divergence of the B. gladioli species.

Effect of Ti Content on the Microstructure and Properties of CoCrFeNiMnTix High Entropy Alloy.

The aim of this study was to investigate the effects of the Ti element addition on the microstructure and properties of CoCrFeNiMn high entropy alloys. The Ti element modified CoCrFeNiMnTix high entropy alloys were prepared by vacuum arc melting processing. The Ti rich body-centered cubic structure phase was observed in CoCrFeNiMnTi0.25 and CoCrFeNiMnTi0.55 instead of a simple face-centered cubic structure in CoCrFeNiMn. The amount of the Ti-rich phase depicted an increasing trend with increasing Ti content. Simultaneously, the mechanical properties of CoCrFeNiMnTix were obviously improved. When the Ti content is 0, 0.25 and 0.55, the microhardness is 175 HV, 253 HV and 646 HV, which has an obvious increasing trend, while the ductility decreased. The tensile properties show a trend of first strengthening and then decreasing, changing from 461 MPa to 631 MPa and then to 287 MPa. When x was 0.55, the solid-liquid transition temperature of the alloy decreased, and the melting temperature range increased.

One-step selective laser patterning of copper/graphene flexible electrodes.

Flexible electrodes have attracted much attention in consumer electronic applications. In this work, laser direct writing is used to fabricate copper/graphene composite electrodes on a flexible substrate in one step. This direct writing process with a low power laser can reduce copper ions in thin films to form copper nanomaterials and spontaneously interconnect them to gain good conductivity, while the laser also induces the growth of multi-layer graphene that coats on copper to improve the oxidation resistance of electrodes. The electrical performance and chemical composition of flexible electrodes can be tuned by laser power, scanning speed, and defocus distance. A mechanism of in situ reduction and interconnection of copper nanomaterials during laser direct writing has been proposed. This method could largely reduce the oxidation issue by avoiding synthesis and sintering processes of copper nanomaterials. These as-written copper electrodes have good stability and have potential applications in flexible electronics, such as flexible heaters or antennas as demonstrated.

Expression and prognostic value of Ars2 in hepatocellular carcinoma.

BACKGROUND: Hepatocellular carcinoma (HCC) is one of the most common malignant tumors in China. Arsenic resistance protein 2 (Asr2) was reported to be important for microRNA (miR) biogenesis, and its depletion could reduce the levels of several miRs, including miR-21, which is over-expressed in HCC. We hypothesized that Ars2 is also overexpressed in HCC and may be involved in the biological properties of HCC. METHODS: Ars2 immunolabeling was evaluated in 132 HCCs. Ars2 immunolabeling, Ars2 qRT-PCR and miR-21 were evaluated in 20 HCCs and in paired normal tissues. Ars2 shRNA was transfected into SMCC-7721 and HepG2 HCC cells. The cell proliferation and expression of Ars2 and miR-21 were subsequently evaluated. RESULTS: Ars2 was expressed primarily in the nucleus of HCC cells. The expression of Ars2 was statistically correlated with the loss of HCC differentiation and pathological stage. The survival rates of patients with low Ars2 expression in HCC were statistically higher than patients with overexpressed Ars2 in HCC. Ars2 and miR-21 were more highly expressed in HCC specimens than normal tissues, and they were also correlated. The knockdown of Ars2 in HCC cells inhibited miR-21 expression and cell proliferation. CONCLUSIONS: Ars2 is overexpressed in HCC and may have prognostic value; it might play an important role in HCC proliferation and miR-21 expression.

Reinforcing Mechanism of WC Particles in Fe-Based Amorphous Matrix Coating on Magnesium Alloy Surface.

To protect magnesium alloy surfaces from wear and corrosion, an Fe-based amorphous coating was prepared on WE43 through the Ni60 interlayer by high-velocity oxygen-fuel (HVOF) spraying. The porosity was ~1%, and the amorphous content exceeded 90%. The wear and corrosion resistance of the composite coating with WC particles wrapped in a Ni layer as the reinforcing phase were compared with that of the completely amorphous coating. The friction coefficient (COF) of the composite coating was 0.3, which is only half of that of the WE43 substrate, and the composite coating exhibited a more stable wear behavior than the completely amorphous coating. The corrosion tendency of the composite coating is lower than that of stainless steel, with a corrosion potential of -0.331 V, and the addition of WC particles did not deteriorate the corrosion resistance considerably. The bonding mechanism of the bonding interface between the amorphous structure and the particles of the reinforcing phase was investigated by transmission electron microscopy (TEM). Reinforcing particles were confirmed to form metallurgical bonding with the coating. It was found that the Ni layer showed excellent bonding performance in the form of a mixture that is amorphous and nanocrystalline. Therefore, the Fe-based amorphous composite coating on a magnesium alloy surface shows a potential protective effect.