Profile of immunoglobulin G N-glycome in COVID-19 patients: A case-control study

Coronavirus disease 2019 (COVID-19) remains a major health challenge globally. Previous studies have suggested that changes in the glycosylation of IgG are closely associated with the severity of COVID-19. This study aimed to compare the profiles of IgG N-glycome between COVID-19 patients and healthy controls. A case-control study was conducted, in which 104 COVID-19 patients and 104 age- and sex-matched healthy individuals were recruited. Serum IgG N-glycome composition was analyzed by hydrophilic interaction liquid chromatography with the ultra-high-performance liquid chromatography (HILIC-UPLC) approach. COVID-19 patients have a decreased level of IgG fucosylation, which upregulates antibody-dependent cell cytotoxicity (ADCC) in acute immune responses. In severe cases, a low level of IgG sialylation contributes to the ADCC-regulated enhancement of inflammatory cytokines. The decreases in sialylation and galactosylation play a role in COVID-19 pathogenesis via the activation of the lectin-initiated alternative complement pathway. IgG N-glycosylation underlines the complex clinical phenotypes of SARS-CoV-2 infection

Supercritical Carbon Dioxide Extraction of Bioactive Compounds from Ampelopsis grossedentata Stems: Process Optimization and Antioxidant Activity

Supercritical carbon dioxide (SC-CO2) extraction of bioactive compounds including flavonoids and phenolics from Ampelopsis grossedentata stems was carried out. Extraction parameters such as pressure, temperature, dynamic time and modifier, were optimized using an orthogonal array design of L9 (34), and antioxidant activities of the extracts were evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assay and ferrous ion chelating (FIC) assay. The best conditions obtained for SC-CO2 extraction of flavonoids was 250 bar, 40 °C, 50 min, and with a modifier of methanol/ethanol (1:3, v/v), and that for phenolics extraction was 250 bar, 40 °C, 50 min, and with a modifier of methanol/ethanol (1:1, v/v). Meantime, flavonoids and phenolics were found to be mainly responsible for the DPPH scavenging activity of the extracts, but not for the chelating activity on ferrous ion according to Pearson correlation analysis. Furthermore, several unreported flavonoids such as apigenin, vitexin, luteolin, etc., have been detected in the extracts from A. grossedentata stems

Short-Term Synaptic Plasticity Mimicked on Ionic/Electronic Hybrid Oxide Synaptic Transistor Gated by Nanogranular SiO2 Films

An indiumezinc-oxide (IZO) based ionic/electronic hybrid synaptic transistor gated by field-configurable nanogranular SiO2 films was reported. The devices exhibited a high current ON/OFF ratio of above 107, a high electron mobility of similar to 14 cm(2) V-1 s(-1) and a low subthreshold swing of similar to 80 mV/decade. The gate bias would modulate the interplay between protons and electrons at the channel/dielectric interface. Due to the dynamic modulation of the transient protons flux within the nanogranular SiO2 films, the channel current would be modified dynamically. Short-term synaptic plasticities, such as short-term potentiation and short-term depression, were mimicked on the proposed IZO synaptic transistor. The results indicate that the synaptic transistor proposed here has potential applications in future neuromorphic devices

Catecholated graphene-filled polyimide with enhanced mechanical, thermal, and tribological properties

In order to achieve good dispersion of graphene in polyimide (PI), catecholated graphene (G-Cat) was prepared by 1,3-dipolar cycloaddition reaction ofN-methylglycine and 3,4-dihydroxybenzaldehyde with graphene sheets. G-Cat/PI composites were prepared by in situ polymerization with pyromellitic dianhydride and 4,4-oxydianiline in the presence of G-Cat. The successful modification of graphene was proved by infrared spectroscopy, Raman spectroscopy, and transmission electron microscopy. The comprehensive properties of G-Cat/PI composites were studied by tensile, dynamic mechanical analysis, thermogravimetric analysis, and friction and wear tests. By observing the morphology of wear marks, the friction and wear properties of the composites were emphatically analyzed. Therefore, graphene/PI composites were expected to have broad application prospects in lubrication and wear resistance

An Analytical Model for the Excavation Damage Zone in Tunnel Surrounding Rock

An accurate theoretical model to predict the extent and mechanical behavior of the excavation damage zone (EDZ) in the surrounding rock of deep-buried tunnel is of great importance for the practical engineering applications. Using the elastic-plastic theory and combined with the analysis on the stress characteristics of the tunnel surrounding rock, this paper present a predict model for the EDZ formation and evolution. A three-zone composite mechanical model was established for the tunnel surround rock and the corresponding stress state and displacement field of three zones were derived. The effects of the strain softening and dilatancy during rock deformation was taken into account. The correctness of the proposed model was validated by the existing theoretical models. A sensitivity analysis for different influencing factors in this model was also performed. The results can benefit for the future numerical and experimental studies

Influence of bias voltage on structure and tribocorrosion properties of TiSiCN coating in artificial seawater

The TiSiCN coatings deposited at different bias voltages were fabricated on Ti6Al4V alloy by arc ion plating. The structure and properties of the TiSiCN coating were characterized using scanning electron microscope, X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, nanoindentation, potentiostat and ball-on-plate wear tests. As the bias voltage increases, the TiSiCN coating shows a nanocrystallite/amorphous structure, whereas the phase constitution and grain size changed slightly, and its hardness and tribocorrosion properties also change correspondingly. When the bias voltage is -100 V, the coating has a composite structure of typical nanocrystallite/amorphous, and a small amount of MAX phase of Ti3SiC2. Moreover, the protection potential applied on the coating effectively prevents the electrochemical corrosion of the coating. However, the applied protection potential will accelerate the degradation of the coating when the channel formed between the surface of the wear track and substrate. (C) 2017 Elsevier Inc. All rights reserved

Influence of carbon contents on the structure and tribocorrosion properties of TiSiCN coatings on Ti6Al4V

The TiSiCN coatings were fabricated on Ti6Al4V. The effect of carbon contents on the structure and tribocorrosion properties were studied. The coatings consist of TiN, TiC and Ti(C,N) nanocrystallites, amorphous Si3N4, SiC and little amorphous carbon. The coating (11.9 at% C) exhibits maximum hardness of 39.8 GPa and the best tribocorrosion resistance, which is attributed to the special nanocomposite structure, and the lower friction coefficient of the TiSiCN coating associated with the graphitization effect during sliding in atmosphere. Moreover, the results of tribocorrosion indicate that the volume loss of TiSiCN coatings ascribed to main wear loss and a little corrosion loss, and the synergy between wear and corrosion is a key factor in degenerating the TiSiCN coating