Immune Characteristic Genes and Neutrophil Immune Transformation Studies in Severe COVID-19.

As a disease causing a global pandemic, the progression of symptoms to severe disease in patients with COVID-19 often has adverse outcomes, but research on the immunopathology of COVID-19 severe disease remains limited. In this study, we used mRNA-seq data from the peripheral blood of COVID-19 patients to identify six COVID-19 severe immune characteristic genes (FPR1, FCGR2A, TLR4, S100A12, CXCL1, and L TF), and found neutrophils to be the critical immune cells in COVID-19 severe disease. Subsequently, using scRNA-seq data from bronchoalveolar lavage fluid from COVID-19 patients, neutrophil subtypes highly expressing the S100A family were found to be located at the end of cellular differentiation and tended to release neutrophil extracellular traps. Finally, it was also found that alveolar macrophages, macrophages, and monocytes with a high expression of COVID-19 severe disease immune characteristic genes may influence neutrophils through intercellular ligand-receptor pairs to promote neutrophil extracellular trap release. This study provides immune characteristic genes, critical immune pathways, and immune cells in COVID-19 severe disease, explores intracellular immune transitions of critical immune cells and pit-induced intercellular communication of immune transitions, and provides new biomarkers and potential drug targets for the treatment of patients with COVID-19 severe disease.

Visualization analysis of research hotspots on structural topology optimization based on CiteSpace.

Structural topology optimization has gained widespread attention due to more possibilities of innovative structural design. The current research focus/hotspots, application areas, main research scholars, institutions and the countries involved in structural topology optimization are visually presented through clustering and visual analysis based on CiteSpace. The four metric dimensions of the literatures in this paper are as follows: annual quantity of papers and core countries, core authors and co-authors' institutions, hotspots and burst terms, and the highly co-cited papers. The results show the research hotspots in this field are concentrated on keywords such as "level set method", "sensitivity analysis", "homogenization", "genetic algorithm", etc. Regarding the research frontier, "moving morphable component (MMC)", "additive manufacturing (AM)" and "deep learning" are hot topics. In addition, Y. Sui, Z. Kang and O. Sigmund, etc. have high publications. M. Bendsøe and O. Sigmund have high citations. Dalian University of Technology, Technical University of Denmark, etc. are prominent institutions. Moreover, China accounts for more than 34% in the terms of original WOS literatures following by the USA and Australia. This paper could identify structural topology optimization development patterns for the scholars concerned with this field, especially novices, to quickly focus and track the research priorities.

REDUCTION OF PM2.5 TOXICITY ON HUMAN ALVEOLAR EPITHELIAL CELLS A549 BY TEA POLYPHENOLS.

Tea-derived polyphenols have anticancer and antioxidant properties, and they can regulate oxidative stress. This study was designed to quantify both the toxic effects of fine particulate matter with aerodynamic diameter less than 2.5 µm (PM2.5) and determine whether tea polyphenols could provide a protective effect against PM2.5 toxicity on human alveolar epithelial A549 cells in vitro. Cytotoxic effects of the PM2.5 on A549 cells were measured by means of cell viability, the expression of caspase-3, bax/bcl-2 and C/EBP-homologous protein (CHOP), and the generation of intracellular reactive oxygen species, malondialdehyde and superoxide dismutase. The results showed that tea polyphenols ameliorated some of the adverse effects of PM2.5 on A549 cell viability and superoxide dismutase levels. In addition, tea polyphenols decreased the production of reactive oxygen species, malondialdehyde generation, and apoptosis in response to PM2.5 exposure. Therefore, our results support a role for tea polyphenols in reducing the toxicity of PM2.5, particularly with regard to targeting oxidative stress and apoptosis.

A new 4-Amino-7-Nitro-2,1,3-Benzoxadiazole (ANBD)-Based Fluorescent Probe for the Detection of Hg2.

Based on the photoinduced electron transfer (PET) principle, 4-amino-7-nitro-2,1,3-benzoxadiazole (ANBD) has been used as a fluorophore to develop a new fluorescent probe, 4-(2-N,N-dimethylthioacetamide)amino-7-nitro-2,1,3-benzoxadiazole (2), for the detection of Hg2+. Upon the addition of Hg2+, a 46-fold fluorescence enhancement occurs. Moreover the probe 2 exhibits a high selectivity and sensitivity to Hg2+, even in the presence of other common metal ions. Under optimal reaction conditions, a good linearity can be obtained in the range of 0.5-2.5 µM, and the detection limit is 0.05 µM. In addition, the desulfurization reaction mechanism is proposed based on electrospray ionization mass spectrum. The present study is not only a supplement to the detection method of Hg2+, but also a merit to the development of ANBD-based fluorescent probes.

Development of multi-residue analysis of herbicides in cereal grain by ultra-performance liquid chromatography-electrospray ionization-mass spectrometry.

A rapid and sensitive method was developed for the determination of 50 herbicides in cereal grain by ultra-performance liquid chromatography-electrospray ionization-mass spectrometry (UPLC-ESI-MS). Using acetonitrile effectively extracted 22 kinds of triazine and other basic herbicides, and using 90:10 v/v acetonitrile-phosphate buffer (pH = 7.5) effectively extracted other 28 herbicides. Chromatographic separation was achieved using gradient elution with acetonitrile-water as a mobile phase for 22 triazine and phenylurea herbicides and with 5mM ammonium acetate aqueous solution containing 0.1% formic acid-acetonitrile as a mobile phase for other 28 herbicides. Using matrix-matched standard calibration curve effectively reduced the indirect matrix effects, ensured accurate quantification for these herbicides. The response was linear over two orders of magnitude with a correlation coefficients (r(2)) higher than 0.992. The limits of quantification for the herbicides varied from 0.2 to 25.6 µg kg(-1). The intra- and inter-day precisions (relative standard deviation, RSD) were 2.2-9.3% and 5.7-17.1%, respectively. The recovery varied from 61.6% to 110% with the RSD of 1.6-11.8%. Analyzing soybean, corn and wheat samples from 17 counties evaluated this method. The developed and validated method has high sensitivity, satisfactory recovery and precision, can ensure the multi-class multi-residue analysis at low µg kg(-1) level for the most herbicides in cereal grain.

Residues investigation of fluoroquinolones and sulphonamides and their metabolites in bovine milk by quantification and confirmation using ultra-performance liquid chromatography-tandem mass spectrometry.

A novel UPLC-MS/MS method for quantification and confirmation of eight fluoroquinolones, five sulphonamides (SAs) and four acetyled metabolites in milk is developed. Their main fragmentation pathways were presented. The limits of quantification were in the range of 0.01-0.29 µg kg(-1) for FQs and 0.13-1.68 µg kg(-1) for SAs. Mean recoveries ranging from 61% to 115% were achieved at spiked level of 0.5-100 µg kg(-1). The intra- and inter-day precisions were in the range of 6.3-10.7% and 9.0-13.4%, respectively. This novel approach has high speed and sensitivity, and can ensure the multiclass and multiresidue analysis of bovine milk at low µg kg(-1) level. The content of each analyte residue is much lower than the maximum residue limits. Some residues in milk were confirmed in according to the Commission Decision 657/2002/EC.