Search

Microtubules, polymerized from α-tubulin (TUA) and β-tubulin (TUB) monomers, play a pivotal role in shaping plant morphogenesis according to developmental and environmental cues. Salix psammophila C. Wang & C. Y. Yang is an important shrub plant in sand-fixing afforestation in arid regions, with three significantly distinct plant types shaped under various environments, namely, upright, intermediate, and scattered types. However, how tubulin genes respond to the developmental and environmental signs in S. psammophila has been far less studied. Here, based on RNA-seq, Sanger sequencing, and real-time PCR (RT-PCR) data, we analyzed the phylogeny of tubulins and their expression profiles in S. psammophila among the three plant types. Furthermore, we analyzed the genetic structure and expression pattern of SpsTUB10 in S. psammophila under various abiotic stress treatments. In total, we identified 26 SpsTubulin genes in S. psammophila. The homologous alignment and phylogenetic analysis revealed that these SpsTubulin genes can be classified into two groups, corresponding to the TUA and TUB genes. The expression profiles of these SpsTubulin genes in various organs showed that most SpsTubulin genes were mainly expressed in the root. SpsTUB10 is a member of the TUB IIa group, consisting of two intros and three exons. The SpsTUB10 protein contains a typical GTPase domain and a C-terminal domain, with α-helix and random coil dominant in the secondary and tertiary structures. The RT-PCR results of SpsTUB10 showed an extremely significant difference in expression levels among the root and stem-developing organs between the upright and scattered types, and the transcript level of SpsTUB10 had a significantly negative correlation with the crown-height ratio. Under different treatments, we found that cold, osmotic stress, and short daylight could significantly increase SpsTUB10 expression levels compared to those in the controls, thereby supporting the positive role of SpsTUB10 in stress-induced responses. These results will provide evidence for the SpsTubulin genes' response to the developmental and environmental cues in S. psammophila. [ABSTRACT FROM AUTHOR]

In this paper, a new nanoscale metal Ti particle-reinforced Mg-3Al-1Zn matrix composite was successfully designed and prepared, which is mainly characterized by the fact that in addition to the "light" advantages of magnesium matrix composite, it also realizes bidirectional improvement of strength and ductility of the composite, and can be used as an alternative material for military light vehicle armor and individual armor. The SEM test shows that the nano-Ti particles are uniformly distributed at the grain boundary under the extruded state, which nails the grain boundary, inhibits the grain growth, and significantly refines the grain. XRD tests show that the addition of nano-Ti particles increases the crystallinity of the composite, which is consistent with the SEM test results. In addition, the EBSD test shows that the weakening of the texture of Ti/Mg-3Al-1Zn matrix composites and the increase in the starting probability of slip system are the main reasons for the improvement in ductility. Mechanical tests show that the yield strength, tensile strength, and elongation of the 0.5 wt% Ti/Mg-3Al-1Zn matrix composites exceed the peak values of ASTM B107/B107M-13 by 38.6%, 26.7%, and 20%, respectively. [ABSTRACT FROM AUTHOR]

The copper-clad magnesium composite wire with a diameter of 3.12 mm and good interface bonding was prepared by cold rotary swaging. The effects of cold rotary swaging and annealing temperature on microstructure and properties of the wire were studied by electron backscatter diffraction, transmission electron microscopy, as well as mechanical and electrical properties tests. The results show that the multi-pass cold rotary swaging composite has a great effect on grain refinement, microstructure recovery and structural unit reorientation, and can also make the wire obtain good interfacial bonding quality, improve mechanical properties, and the tensile strength can reach 289 MPa. The width of the interface layer widened with the increase of temperature, and the increase improved significantly at annealing temperatures of 450 °C and 500 °C, and the intermetallic compounds Mg2Cu and MgCu2 were found in the longitudinal section of the wire, respectively. After a reasonable annealing process of 400 °C/1 h, the interface layer did not thicken significantly, and the ductility and conductivity of the wire were the best, and the elongation after fracture and conductivity could reach 17% and 81.1% IACS, which increased by 15.2% and 3.8% compared with before annealing, respectively. [ABSTRACT FROM AUTHOR]

In the field of metal matrix composites, it is a great challenge to improve the strength and elongation of magnesium matrix composites simultaneously. In this work, xTC4/AZ31 (x = 0.5, 1, 1.5 wt.%) composites were fabricated by spark plasma sintering (SPS) followed by hot extrusion. Scanning electron microscopy (SEM) showed that nano-TC4 (Ti-6Al-4V) was well dispersed in the AZ31 matrix. We studied the microstructure evolution and tensile properties of the composites, and analyzed the strengthening mechanism of nano-TC4 on magnesium matrix composites. The results showed that magnesium matrix composites with 1 wt.%TC4 had good comprehensive properties; compared with the AZ31 matrix, the yield strength (YS) was increased by 20.4%, from 162 MPa to 195 MPa; the ultimate tensile strength (UTS) was increased by 11.7%, from 274 MPa to 306 MPa, and the failure strain (FS) was increased by 21.1%, from 7.6% to 9.2%. The improvement in strength was mainly due to grain refinement and good interfacial bonding between nano-TC4 and the Mg matrix. The increase in elongation was the result of grain refinement and a weakened texture. [ABSTRACT FROM AUTHOR]