Porous Nb-Ti based alloy produced from plasma spheroidized powder

Spherical Nb-Ti based alloy powder was prepared by the combination of plasma spheroidization and mechanical alloying. Phase constituents, microstructure and surface state of the powder, and pore characteristics of the resulting porous alloy were investigated. The results show that the undissolved W and V in the mechanically alloyed powder is fully alloyed after spheroidization, and single β phase is achieved. Particle size of the spheroidized powder is in the range of 20–110 μm. With the decrease of particle size, a transformation from typical dendrite solidification structure to fine cell microstructure occurs. The surface of the spheroidized powder is coated by a layer of oxides consisting mainly of TiO2 and Nb2O5. Probabilities of sinter-neck formation and particle coalescence increases with increasing sintering temperature. Porous skeleton with relatively homogeneous pore distribution and open pore channel is formed after vacuum sintering at 1700 °C, and the porosity is 32%. The sintering kinetic analysis indicates that grain boundary diffusion is the primary mass transport mechanism during sintering process. Keywords: Powder metallurgy, Nb-Ti based alloy, Porous material, Mechanical alloying, Plasma spheroidizing, Solidification microstructur

Physiological, Metabolic and Transcriptional Responses of Basil (<i>Ocimum basilicum</i> Linn. var. <i>pilosum</i> (Willd.) Benth.) to Heat Stress

As a medicinal and edible plant, basil (Ocimum basilicum Linn. var. pilosum (Willd.) Benth.) has rich nutrition and significant economic value. The increase in heat stress caused by global warming adversely affects the growth and yield of plants. However, the response mechanism of basil to heat stress is poorly understood. This work investigated the changes in phenotype, metabolome, and transcriptome in basil under heat stress. The results showed that heat stress triggered severe oxidative damage and photosynthesis inhibition in basil. Metabonomic analysis showed that, compared to the control group, 29 significantly differentially accumulated metabolites (DAMs) were identified after 1 d of heat treatment, and 37 DAMs after the treatment of 3 d. The DAMs were significantly enriched by several pathways such as glycolysis or gluconeogenesis; aminoacyl-tRNA biosynthesis; and alanine, aspartate, and glutamate metabolism. In addition, transcriptomic analysis revealed that 15,066 and 15,445 genes were differentially expressed after 1 d and 3 d of heat treatment, respectively. Among them, 11,183 differentially expressed genes (DEGs) were common response genes under 1 d and 3 d heat treatment, including 5437 down-regulated DEGs and 6746 up-regulated DEGs. All DEGs were significantly enriched in various KEGG (Kyoto Encyclopedia of Genes and Genomes) pathways, most dominated by glyoxylate and dicarboxylate metabolism, followed by starch and sucrose metabolism, and by the biosynthesis and metabolism of other secondary metabolites. Overall, all the above results provided some valuable insights into the molecular mechanism of basil in response to heat stress

Physiological, Metabolic and Transcriptional Responses of Basil (Ocimum basilicum Linn. var. pilosum (Willd.) Benth.) to Heat Stress

As a medicinal and edible plant, basil (Ocimum basilicum Linn. var. pilosum (Willd.) Benth.) has rich nutrition and significant economic value. The increase in heat stress caused by global warming adversely affects the growth and yield of plants. However, the response mechanism of basil to heat stress is poorly understood. This work investigated the changes in phenotype, metabolome, and transcriptome in basil under heat stress. The results showed that heat stress triggered severe oxidative damage and photosynthesis inhibition in basil. Metabonomic analysis showed that, compared to the control group, 29 significantly differentially accumulated metabolites (DAMs) were identified after 1 d of heat treatment, and 37 DAMs after the treatment of 3 d. The DAMs were significantly enriched by several pathways such as glycolysis or gluconeogenesis; aminoacyl-tRNA biosynthesis; and alanine, aspartate, and glutamate metabolism. In addition, transcriptomic analysis revealed that 15,066 and 15,445 genes were differentially expressed after 1 d and 3 d of heat treatment, respectively. Among them, 11,183 differentially expressed genes (DEGs) were common response genes under 1 d and 3 d heat treatment, including 5437 down-regulated DEGs and 6746 up-regulated DEGs. All DEGs were significantly enriched in various KEGG (Kyoto Encyclopedia of Genes and Genomes) pathways, most dominated by glyoxylate and dicarboxylate metabolism, followed by starch and sucrose metabolism, and by the biosynthesis and metabolism of other secondary metabolites. Overall, all the above results provided some valuable insights into the molecular mechanism of basil in response to heat stress

Conducting Polyaniline/Au Nanorods Composite Film for High-Performance Electrochromic Device

Conducting polymers are promising candidate materials in next-generation electrochromic applications due to their multicolour changes, flexible and large-scale production capability; however, poor cycling stability and relatively low optical modulation limit their widespread application. In this article, a simple electrochemical deposition method is used to create a polyaniline (PANI)/Au nanorods composite electrochromic film on ITO glass as an electrode. This PANI/Au nanorods composite film has better electrochromic properties than the straight PANI film. Moreover, the electrochromic device (ECD) was successfully fabricated by PANI/Au nanorods composite film as anode and poly(3,4-ethyloxylthiophene) as the cathode. This resultant device exhibits perfect electrochromic performance, including higher optical modulation (56%), a faster response time (0.6 s for bleaching and 0.9 s for colouring) and good cycling stability (sustained 85% after 6750 cycles). Notably, the geometric structure of the film is formed by the Au nanorods coated with PANI, which not only can provide transport channel and ion storage space but also improving the conductivity. In addition, the composite structure can provide larger surface area and benefit the electrolyte ions insertion and extraction from the composite electrode film. The rational design of stacking nanocomposites on electrodes may be a useful method for fabricating high-performance ECDs

A Novel Semi‐Cannulated Screw Enhanced Bone Cement Augmentation and Pullout Strength in Posterior Cervical Lateral Mass Screw Fixations: An In Vitro Biomechanical and Morphological Study

Objective To develop a novel semi‐cannulated lateral mass screw (SC‐LMS) for cervical posterior fixations and compare the fixation stability and safety of SC‐LMS with regular solid lateral mass screw (S‐LMS) in bone cement augmentation and pullout strength using fresh cadaveric cervical vertebrae. Methods The conventional multiaxial screw for cervical lateral mass fixation was modified to a cannulated screw with two lateral holes, used for bone cement injection in situ. Eight fresh human cervical vertebrae (C3, C4, and C5) were collected and used. μCT scan was performed to evaluate the bone quality of the lateral masses, including bone mineral density (BMD), trabecular thickness (Tb.Th), and trabecular separation (Tb.Sp). SCLMS or S‐LMS were randomly inserted into the paired cervical vertebrae and pulled out as a screw loosening model. These screws were reinserted in with bone cement augmentation, scanned by μCT to obtain the bone cement distribution along the screws, and pulled out to test the screw purchase strength. Results Fmax values exhibited strong positive correlations with the local BMD ( = 0.8640, p < 0.0001) and Tb.Th ( = 0.6795, p = 0.0038), whereas a negative correlation with Tb.Sp ( = −0.5567, p = 0.0251). A significant difference was observed between the Fmax before and after PMMA injection on the SC‐LMS side (p = 0.019). The SC‐LMS exhibited lower risk of cement leakage than S‐LMS after PMMA injection, and a positive correlation was observed between max and the distribution volumes on the SC‐LMS side. Conclusion The novel SC‐LMS provides more robust fixation stability and is safer than the S‐LMS for PMMA augmentation, which may be related to the cement‐screw‐cement‐bone complex formation