Function of duck (Anas platyrhynchos) major histocompatibility complex class I (Anpl-MHC I) molecules in binding peptides is through the peptide binding groove (PBG), which is thought to be influenced by the high polymorphism of α1 and α2 domains. However, little is known about the polymorphism of Anpl-MHC I peptide binding domain (PBD), especially in the domestic duck. Here, we analyzed the polymorphism of forty-eight Anpl-MHC I α1 and α2 domains from domestic duck breeds previously reported. All sequences were analyzed through multiple sequence alignment and a phylogenetic tree was constructed. The coefficient of variance of the peptide binding domains (PBDs) from WS, CV, JD, and SX duck breeds was estimated based on the Wu-Kabat variability index, followed by the location of the highly variable sites (HVSs) on reported crystal structure models. Analysis of α1 and α2 domains showed common features of classical MHC class I and high polymorphism, especially in α1 domain. The constructed phylogenetic tree showed that PBDs of domestic ducks did not segregate based on breeds and had a close phylogenetic relationship, even with wild ducks. In each breed, HVSs were mostly located in the PBG, suggesting that they might determine peptide-binding characteristics and subsequently influence peptide presentation and recognition. The combined results of sequence data and crystal structure provide novel valuable insights into the polymorphism and diversity of Anpl-MHC I PBDs that will facilitate further studies on disease resistance differences between duck breeds and the development of cytotoxic T-lymphocyte (CTL) epitope vaccines suited for preventing diseases in domestic ducks.
This study aims to design a novel air cleaning facility which conforms to the current situation in China, and moreover can satisfy our demand on air purification under the condition of poor air quality, as well as discuss the development means of a prototype product. Air conditions in the operating room of a hospital were measured as the research subject of this study. First, a suitable turbulence model and boundary conditions were selected and computational fluid dynamics (CFD) software was used to simulate indoor air distribution. The analysis and comparison of the simulation results suggested that increasing the area of air supply outlets and the number of return air inlets would not only increase the area of unidirectional flow region in main flow region, but also avoid an indoor vortex and turbulivity of the operating area. Based on the summary of heat and humidity management methods, the system operation mode and relevant parameter technologies as well as the characteristics of the thermal-humidity load of the operating room were analyzed and compiled. According to the load value and parameters of indoor design obtained after our calculations, the airflow distribution of purifying the air-conditioning system in a clean operating room was designed and checked. The research results suggested that the application of a secondary return air system in the summer could reduce energy consumption and be consistent with the concept of primary humidity control. This study analyzed the feasibility and energy conservation properties of cleaning air-conditioning technology in operating rooms, proposed some solutions to the problem, and performed a feasible simulation, which provides a reference for practical engineering.
Twinned dendrites in Al-Zn alloy with high Zn content (40% wt.%) were successfully prepared by directional solidification. At different directional solidification rates (1000 and 1500 μm/s), microstructures and growth orientation variations of Al twinned dendrite and non-twinned dendrite were characterized. By using the inverted trapezoidal graphite sleeve at 1000 μm/s, Al twinned dendrite were formed to developed feather crystal structures in longitudinal section. Its primary and secondary twinned dendrite were grew along  direction. Moreover the deviation angle between  direction of Al twinned dendrite and the heat flow direction was about 27.15°. While not using the inverted trapezoidal graphite sleeve at 1000 and 1500 μm/s, Al dendrite was the non-twinned dendrite and the twinned dendrite was not appeared. The experimental results showed that the higher temperature gradient, a certain pulling rate and convection environment were the formation conditions of twinned dendrites.