A New Method for Preparing Titanium Aluminium Alloy Powder

Due to TiAl alloys’ excellent properties, TiAl alloys have received widespread attention from researchers. However, the high energy consumption and lengthy process of traditional preparation methods have always limited the large-scale application of TiAl alloys. This article develops a new method for preparing TiAl-based alloy powder via the magnesium thermal reduction of TiO2 in AlCl3-KCl molten salt. In this study, the proportion of AlCl3&KCl molten salts was determined. We conducted phase analysis on the final product by studying the changes in temperature and time. It was found that the TiAl3 alloy powder could be obtained by being kept at 750 °C for 2 h, with an oxygen content of 3.91 wt%. The reaction process for the entire experiment was determined through thermodynamic calculations and experimental analysis, and the principles of the reduction process are discussed

Evolutionarily conserved IL-27β enhances Th1 cells potential by triggering the JAK1/STAT1/T-bet axis in Nile tilapia

As a pleiotropic cytokine in the interleukin (IL)-12 family, IL-27β plays a significant role in regulating immune cell responses, eliminating invading pathogens, and maintaining immune homeostasis. Although non-mammalian IL-27β homologs have been identified, the mechanism of whether and how it is involved in adaptive immunity in early vertebrates remains unclear. In this study, we identified an evolutionarily conserved IL-27β (defined as OnIL-27β) from Nile tilapia (Oreochromis niloticus), and explored its conserved status through gene collinearity, gene structure, functional domain, tertiary structure, multiple sequence alignment, and phylogeny analysis. IL-27β was widely expressed in the immune-related tissues/organ of tilapia. The expression of OnIL-27β in spleen lymphocytes increased significantly at the adaptive immune phase after Edwardsiella piscicida infection. OnIL-27β can bind to precursor cells, T cells, and other lymphocytes to varying degrees. Additionally, IL-27β may be involved in lymphocyte-mediated immune responses through activation of Erk and JNK pathways. More importantly, we found that IL-27β enhanced the mRNA expression of the Th1 cell-associated cytokine IFN-γ and the transcription factor T-bet. This potential enhancement of the Th1 response may be attributed to the activation of the JAK1/STAT1/T-bet axis by IL-27β, as it induced increased transcript levels of JAK1, STAT1 but not TYK2 and STAT4. This study provides a new perspective for understanding the origin, evolution and function of the adaptive immune system in teleost

Deoxidation thermodynamics of Ti–O in hydrogen atmosphere: Preparation of TiH2 alloy powder by direct reduction of spent V2O5–WO3/TiO2 catalyst with magnesiothermic

The abundant metal Ti is a high-quality metal with lightweight, high strength, and corrosion resistance. However, due to its harsh preparation conditions, the price remains high, so titanium metal's simple and effective products have become a challenge for the world's scientific research community. In this paper, by calculating the oxygen potential of Ti–O, Ti–H, and Ti–H–O solid solutions, the oxygen potential of Ti–H–O was obtained when the oxygen content was 0.03 and 0.009. As H2 enters the Ti–O lattice, the oxygen potential of the Ti–H–O system increases with the increase of H content. Thermodynamic calculations showed that introducing hydrogen effectively destroyed the stability of Ti–O solid solutions. At the same time, this paper uses a magnesiothermic as a reducing agent. To verify the feasibility of the above thermodynamics, reduce the spent V2O5–WO3/TiO2 catalyst (Ti > 80 wt%) of titanium-rich materials in a hydrogen atmosphere. Finally, the spent V2O5–WO3/TiO2 catalyst was reduced at 750 °C for 8–24 h to obtain TiH2 powder with an oxygen content of 0.9 wt%

Influences of sintering temperature on pore morphology, porosity, and mechanical behavior of porous Ti

The purpose of this study was to determine the influences of the sintering temperature on the pore morphology, porosity, and mechanical behavior of titanium foams. Porous Ti samples were successfully manufactured using the metal powder metallurgy method in conjunction with sintering at the four temperatures (900, 1000, 1100, and 1200 °C). The sintering temperature significantly influenced the pore morphology, porosity, and mechanical behavior of the titanium foams. The titanium foams were characterized using an optical microscope in conjunction with scanning electron microscopy. A fracture showed the appearance and growth of a sintering neck between adjacent particles. As the sintering temperature increased, the sintering necks gradually became clearer. The porosity decreased from 56.48% to 46.83% as the sintering temperature increased from 900 °C to 1200 °C, while the initial yield strength of the porous titanium increased from 101.81 to 208.01 MPa. The porous titanium foams produced by the metal powder metallurgy method have a significant utilization potential in hard-tissue engineering

Large enhancement of Blocking temperature by control of interfacial structures in Pt/NiFe/IrMn/MgO/Pt multilayers

The Blocking temperature (TB) of Pt/NiFe/IrMn/MgO/Pt multilayers was greatly enhanced from far below room temperature (RT) to above RT by inserting 1 nm thick Mg layer at IrMn/MgO interface. Furthermore, the exchange bias field (Heb) was increased as well by the control of interfacial structures. The evidence for a significant fraction of Mn-O bonding at IrMn/MgO interface without Mg insertion layer was provided by X-ray photoelectron spectroscopy. The bonding between Mn and O can decrease the antiferromagnetism of IrMn film, leading to lower value of TB in Pt/NiFe/IrMn/MgO/Pt multilayers. Ultrathin Mg film inserted at IrMn/MgO interface acting as an oxygen sinking layer can suppress the oxidation reactions between Mn and O and reduce the formation of Mn-O bonding greatly. The oxidation suppression results in the recovery of the antiferromagnetism of IrMn film, which can enhance TB and Heb. Furthermore, the high resolution transmission electron microscopy demonstrates that the Mg insertion layer can efficiently promote a high-quality MgO (200) texture. This study will enhance the understanding of physics in antiferromagnet-based spintronic devices

S6K1/S6 axis-regulated lymphocyte activation is important for adaptive immune response of Nile tilapia

Ribosomal protein S6 kinase beta-1 (S6K1) is a serine/threonine kinase downstream of the mechanistic target of rapamycin (mTOR) pathway, and plays crucial roles in immune regulation. Although remarkable progress has been achieved with a mouse model, how S6K1 regulates adaptive immunity is largely unknown in early vertebrates. In this study, we identified an S6K1 from Nile tilapia Oreochromis niloticus (OnS6K1), and further investigated its potential regulatory role on the adaptive immunity of this fish species. Both sequence and structure of OnS6K1 were highly conserved with its homologs from other vertebrates and invertebrates. OnS6K1 was widely expressed in immune tissues, and with a relative higher expression level in the liver, spleen and head kidney. At the adaptive immune stage of Nile tilapia that infected with Aeromonas hydrophila, mRNA expression of OnS6K1 and its downstream effector S6 was significantly up-regulated in spleen lymphocytes. Meanwhile, their phosphorylation level was also enhanced during this process, suggesting that S6K1/S6 axis participated in the primary response of anti-bacterial adaptive immunity in Nile tilapia. Furthermore, after spleen lymphocytes were activated by the T cell-specific mitogen PHA or lymphocytes agonist PMA in vitro, mRNA and phosphorylation levels of S6K1 were elevated, and phosphorylation of S6 was also enhanced. Once S6K1 activity was blocked by a specific inhibitor, both mRNA and phosphorylation levels of S6 were severely impaired. More importantly, blockade of S6K1/S6 axis reduced the expression of T cell activation marker IFN-gamma and CD122 in PHA-activated spleen lymphocytes, indicating the essential role of S6K1/S6 axis in regulating T cell activation of Nile tilapia. Together, our study suggests that S6K1 and its effector S6 regulate lymphocyte activation of Nile tilapia, and in turn promote lymphocyte-mediated adaptive immunity. This study enriched the mechanism of adaptive immune response in teleost and provided useful clues to understand the evolution of adaptive immune system