Detecting the Deformation Behavior of Bimodal Ti-6Al-4V Using a Digital Image Correlation Technique.

The evolution of a local strain of the Ti-6Al-4V alloy subjected to tensile loading was investigated in situ by using the digital image correlation technique. The results show that some local strain concentration areas have already appeared in the elastic deformation stage, which then connected and became concentrated in the gauge region when the specimen yielded. The strain compatibility of grains in the macroscopic region is kept constant. The deformation process is further divided into six parts based on the development of the maximum strain gradient, and the strain compatibility of each stage of the alloy is summarized and analyzed. The quasi-in situ experiment reveals that the primary α(αp) grains undertake the main deformation at the micro-scale.

Molecular cloning and expression of a cucumber (Cucumis sativus L.) heme oxygenase-1 gene, CsHO1, which is involved in adventitious root formation.

Our previous work showed that in cucumber (Cucumis sativus), auxin rapidly induces heme oxygenase (HO) activity and the product of HO action, carbon monoxide (CO), then triggers the signal transduction events leading to adventitious root formation. In this study, the cucumber HO-1 gene (named as CsHO1) was isolated and sequenced. It contains four exons and three introns and encodes a polypeptide of 291 amino acids. Further results show that CsHO1 shares a high homology with plant HO-1 proteins and codes a 33.3 kDa protein with a 65-amino transit peptide, predicting a mature protein of 26.1 kDa. The mature CsHO1 was expressed in Escherichia coli to produce a fusion protein, which exhibits HO activity. The CsHO1:GFP fusion protein was localized in the chloroplast. Related biochemical analyses of mature CsHO1, including Vmax, Km, Topt and pHopt, were also investigated. CsHO1 mRNA was found in germinating seeds, roots, stem, and especially in leaf tissues. Several well-known adventitious root inducers, including auxin, ABA, hemin, nitric oxide donor sodium nitroprusside (SNP), CaCl(2), and sodium hydrosulfide (NaHS), differentially up-regulate CsHO1 transcripts and corresponding protein levels. These results suggest that CsHO1 may be involved in cucumber adventitious rooting.