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MHC molecules are found in all jawed vertebrates and are known to present peptides to T lymphocytes. In mammals, peptides can hang out either end of the peptide-binding groove of classical class II molecules, whereas the N and C termini of peptides are typically tightly bound to specific pockets in classical class I molecules. The chicken MHC, like many nonmammalian vertebrates, has a single dominantly expressed classical class I molecule encoded by the BF2 locus. We determined the structures of BF2*1201 bound to two peptides and found that the C terminus of one peptide hangs outside of the groove with a conformation much like the peptides bound to class II molecules. We found that BF2*1201 binds many peptides that hang out of the groove at the C terminus, and the sequences and structures of this MHC class I allele were determined to investigate the basis for this phenomenon. The classical class I molecules of mammals have a nearly invariant Tyr (Tyr84 in humans) that coordinates the peptide C terminus, but all classical class I molecules outside of mammals have an Arg in that position in common with mammalian class II molecules. We find that this invariant Arg residue switches conformation to allow peptides to hang out of the groove of BF2*1201, suggesting that this phenomenon is common in chickens and other nonmammalian vertebrates, perhaps allowing the single dominantly expressed class I molecule to bind a larger repertoire of peptides.

After nearly 20 years of development, the advanced technology of remote tower have become increasingly mature and have been approved for operation in many cities. This paper introduces the concept and operation mode of remote tower, summarizes the application status of remote tower in different countries, studies the key technologies and verification methods involved in remote tower system, and analyzes the application prospect of remote tower in China. Finally, the challenges and difficulties in the research of remote tower system are presented.

In order to accelerate domestic civil aviation technology development, raise the level of high-tech application, and keep up with the development trend of international civil aviation technology, an Evolution-Simulation-Verification framework was proposed in this paper. First, sort out the evolution model of the improvement area, clarify its roadmap, and then use digital twins or other numerical simulation methods to verify the concept and principle. When the corresponding product is developed, it will be deployed in the verification airport for testing. After the function and performance of the product meet the requirements, add it to the product library for selection. Through the above process, current problems could be handled, meanwhile, the evolution model can be continuously optimized and keep the roadmap advanced. The simulation and verification work can fully use the existing digital and physical resources to form an ecology to promote and guarantee the development of the aviation industry.

Background: Coronavirus disease 2019 (COVID-19) is a new viral respiratory disease and whether pregnant women are at increased risk of infection is unknown. Viral pneumonia is an important indirect cause of maternal death. Little is known about the effects of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) during pregnancy. Objective: To describe the clinical characteristics of COVID-19 in pregnancy and their newborn infant, and we sought to explored whether the SARS-CoV-2 can be intrauterine vertically transmitted. Study Design: The study was a case series study conducted in the obstetric ward of Tongji Hospital affiliated to Huazhong University of science and technology, Wuhan, China. Demographic, clinical, laboratory and radiological profiles of the SARS-CoV-2 infection case series. A systematic testing procedure for SARS-CoV-2 infection using oropharyngeal swab, placenta tissue, vaginal mucus, and breast milk of mothers. and oropharyngeal swab, umbilical cord blood, and serum of newborns was conducted. Results: We have conducted the most thorough virological assessment to date, and we include a longer clinical observation in mother-infant dyads during hospitalization. The clinical course and outcomes of three pregnant women who acquired SARS-CoV-2 infection late pregnancy are described in mother-infant dyads. Two had caesarean delivery in their third trimester. All patients showed an uneventful perinatal course, and a successful outcome. No infants became infected by vertical transmission or during delivery. Conclusion: No evidence to suggest the potential risk of intrauterine vertical transmission in the case series and further in-depth study is needed. Both the pregnancy woman and infant showed fewer adverse maternal and neonatal outcomes.

By successive impregnation method, the Ce-modified Cu-O/γ-Al2O3 catalyst was prepared and characterized using nitrogen adsorption-desorption, scanning electron microscopy energy dispersive X-ray analysis (SEM-EDS), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman, and H2-Temperature programming reduction (H2-TPR). In catalytic wet-air oxidation (CWAO) process for the printing and dyeing wastewater (PDW), the effects of Ce addition on performance, mechanism and kinetics of the catalyst were investigated. The Ce addition increases the Brunauer-Emmett-Teller (BET) surface area and pore volume of the catalyst and makes the active components uniformly distributed on the catalyst surface. Formation of a stable CuAl2O4 solid solution by anchoring Cu onto the γ-Al2O3 crystal lattice leads to a significant decrease in metal leaching of the Ce-modified catalyst. The proportion of lattice oxygen in the catalyst substantially increases and the apparent activation energy of Cu-O/γ-Al2O3 catalyst decreases owing to Ce addition. Therefore, the catalytic activity and stability of the Ce-modified catalyst are considerably improved. The scavengers experiments identify the active species existed in the CWAO reaction system, with the order of reactivity: h+ > O2•− > H2O2 > HO•. This novel Cu-Ce-O/γ-Al2O3 catalyst has great potential in applications for treatment of concentrated organic wastewater due to its superior catalytic activity and improved stability.

A series of novel Pt-modified Cu–Fe–La/γ-Al2O3 catalysts were prepared by an incipient-wetness impregnation method, and their performances were evaluated in catalytic wet air oxidation (CWAO) of printing and dyeing wastewater (PDW). The as-prepared catalysts were characterized by X-ray photoelectron spectroscopy (XPS), nitrogen adsorption–desorption, X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), Raman spectroscopy, and temperature programmed reduction by hydrogen (H2-TPR). The effects of catalyst composition and calcination temperature on the catalytic performance were investigated. The chemical oxygen demand (COD) removal efficiency and decolorization rate are satisfactory over Cu1.5Fe1.5La3/γ-Al2O3 catalyst, with poor stability under CWAO conditions. In contrast, catalytic performance and stability of all Pt-modified catalysts are significantly improved. With increasing calcination temperatures from 350 °C to 750 °C, the activity of the catalysts significantly decreases from 97.3% to 84.6%, and the size of the particles varies from 4.71–6.95 nm. The XRD, HRTEM, and XPS results indicate that the Pt1Cu1Fe1La3/γ-Al2O3 catalyst mostly comprises Pt, CuO, Fe3O4, and La2O3, and the incorporation of Pt increases the binding energies (BEs) of the metal elements in the catalyst, owing to synergistic interactions between the Pt and the Cu, Fe, and La elements. After five cycles, the COD removal efficiency and decolorization rate for PDW over the Pt1Cu1Fe1La3/γ-Al2O3 catalyst calcined at 650 °C remain comparable with the fresh catalyst, indicating that Pt-modified Cu–Fe–La/γ-Al2O3 ternary oxide is a promising catalyst with high activity and stability for CWAO treatment.