Optimization of 3D Printing Parameters for Alumina Ceramic Based on the Orthogonal Test.

In this paper, an alumina ink with good rheological properties was successfully prepared using pseudoboehmite as the main component, nitric acid as the colloidal solvent, and sesbania powder as the lubricant. The impact of nine different ink formulations, namely, Ink1 to Ink9, on the printability and rheological features of the ink was investigated. Consequently, it was found that Ink3 with 5 wt % nitric acid and 5 wt % sesbania powder exhibited the most favorable formability. This ink was utilized to fabricate alumina samples with direct ink writing (DIW) three-dimensional (3D) printing technology. The printed alumina samples were characterized using an automatic Brunauer-Emmett-Teller, X-ray diffractometer, Fourier transform infrared spectroscopy, and scanning electron microscope. To obtain the optimal printing parameters, a three-factor and three-level orthogonal test was designed to research the influences of different 3D printing parameters (filling ratio, nozzle diameter, and layer thickness) on the specific surface area, pore characteristics (size and volume), and radial crushing strength of the alumina specimens. The primary and secondary orders of the effects on the radial crushing strength and pore structure were determined through analysis of the experimental data. The experimental results showed that the alumina sample with a filling ratio of 80%, nozzle diameter of 0.6 mm, and layer thickness of 0.3 mm was found to have better strength of 48.07 ± 9.53 N/mm and specific surface area of 185.7315 m2/g. This study provides a theoretical base for the preparation of alumina carriers by DIW 3D printing.

A novel type-II-II heterojunction for photocatalytic degradation of LEV based on the built-in electric field: carrier transfer mechanism and DFT calculation.

Heterojunctions play a crucial role in improving the absorption of visible light and performance of photocatalysts for organic contaminants degradation in water. In this work, a novel type-II-II Ag2CO3/Bi2WO6 (AB) heterojunction was synthesized by hydrothermal reaction and in situ-precipitation methods. The mechanisms of charge transfer and carrier separation at the interface of heterojunctions and the influence on the photocatalytic activity were investigated. The degradation of levofloxacin (LEV) under visible light irradiation was employed to evaluate the photocatalytic performance of AB. The results showed that 85.4% LEV was degraded by AB, which was 1.38 and 1.39 times higher than that of Bi2WO6 and Ag2CO3, respectively. The work functions of the different crystal planes in the AB heterojunction, which was calculated by density functional theory, are a significant difference. The Fermi energy (Ef) of Ag2CO3 (- 6.005 eV) is lower than Bi2WO6 (- 3.659 eV), but the conduction band (CB) is higher. Therefore, using AB heterojunctions as an example, the research explored the mechanism of type-II-II which CB and Ef of one semiconductor cannot simultaneously surpass those of another material, based on the built-in electric field theory. Through this analysis, a deeper understanding of type-II heterojunctions was achieved, and providing valuable insights into the behavior of this specific heterojunction system.

Comparative proteomic discovery of salt stress response in alfalfa roots and overexpression of MsANN2 confers salt tolerance.

Soil salinity constrains growth, development and yield of alfalfa (Medicago sativa L.). To illustrate the molecular mechanisms responsible for salt tolerance, a comparative proteome analysis was explored to characterize protein profiles of alfalfa seedling roots exposed to 100 and 200 mM NaCl for three weeks. There were 52 differentially expressed proteins identified, among which the mRNA expressions of 12 were verified by Real-Time-PCR analysis. The results showed increase in abundance of ascorbate peroxidase, POD, CBS protein and PR-10 in salt-stressed alfalfa, suggesting an effectively antioxidant and defense systems. Alfalfa enhanced protein quality control system to refold or degrade abnormal proteins induced by salt stress through upregulation of unfolded protein response (UPR) marker PDIs and molecular chaperones (eg. HSP70, TCP-1, and GroES) as well as the ubiquitin-proteasome system (UPS) including ubiquitin ligase enzyme (E3) and proteasome subunits. Upregulation of proteins responsible for calcium signal transduction including calmodulin and annexin helped alfalfa adapt to salt stress. Specifically, annexin (MsANN2), a key Ca2+-binding protein, was selected for further characterization. The heterologous of the MsANN2 in Arabidopsis conferred salt tolerance. These results provide detailed information for salt-responsive root proteins and highlight the importance of MsANN2 in adapting to salt stress in alfalfa.

Inhibition of Cell Apoptosis by Apicomplexan Protozoa-Host Interaction in the Early Stage of Infection.

Apicomplexan protozoa, which are a group of specialized intracellular parasitic protozoa, infect humans and other animals and cause a variety of diseases. The lack of research on the interaction mechanism between Apicomplexan protozoa and their hosts is a key factor restricting the development of new drugs and vaccines. In the early stages of infection, cell apoptosis is inhibited by Apicomplexan protozoa through their interaction with the host cells; thereby, the survival and reproduction of Apicomplexan protozoa in host cells is promoted. In this review, the key virulence proteins and pathways are introduced regarding the inhibition of cell apoptosis by the interaction between the protozoa and their host during the early stage of Apicomplexan protozoa infection. It provides a theoretical basis for the development of drugs or vaccines for protozoal diseases.