Critical Role of Simultaneous Reduction of Atmospheric Odd Oxygen for Winter Haze Mitigation.

The lockdown due to COVID-19 created a rare opportunity to examine the nonlinear responses of secondary aerosols, which are formed through atmospheric oxidation of gaseous precursors, to intensive precursor emission reductions. Based on unique observational data sets from six supersites in eastern China during 2019-2021, we found that the lockdown caused considerable decreases (32-61%) in different secondary aerosol components in the study region because of similar-degree precursor reductions. However, due to insufficient combustion-related volatile organic compound (VOC) reduction, odd oxygen (Ox = O3 + NO2) concentration, an indicator of the extent of photochemical processing, showed little change and did not promote more decreases in secondary aerosols. We also found that the Chinese provinces and international cities that experienced reduced Ox during the lockdown usually gained a greater simultaneous PM2.5 decrease than other provinces and cities with an increased Ox. Therefore, we argue that strict VOC control in winter, which has been largely ignored so far, is critical in future policies to mitigate winter haze more efficiently by reducing Ox simultaneously.

Sample-to-cutoff ratios using Architect HIV Ag/Ab Combo: The influence with the results of supplemental tests and optimal cutoff value to predict HIV infection.

BACKGROUND: The Architect HIV Ag/Ab Combo has excellent performance for HIV screening; however, the false-positive rate (FPR) was high in low HIV prevalence setting. OBJECTIVES: The purpose of this study was to analyze the influence of sample-to-cutoff (s/co) ratios by Architect HIV Ag/Ab Combo with the results of confirmatory test and explore the potential utility of s/co to predict HIV infection. METHODS: A retrospective review on Architect HIV Ag/Ab Combo reactive results was performed at a teaching hospital in Xi'an. The s/co values in different groups, that is, true positives (TP) and false positives (FP), different Western blotting (WB) bands among WB-positive cases, were compared. The receiver operating characteristic curve (ROC) analysis was used to determine the optimal cutoff value for predicting HIV infection. RESULTS: During the study period, 219 out of 84 702 patients were reactive by ARCHITECT with a 0.0992% of HIV prevalence and a 56.25% of FPR. The mean s/co ratios in TP were significantly higher than that in FP (458.15 vs 3.11, P < 0.0001). Among the WB-positive cases, the s/co ratios increased significantly with the increase in the number of bands, P = 0.0065. The optimal cutoff (24.44) by ROC analysis can provide the highest sum of sensitivity (100%) and specificity (100%) with no FP results. CONCLUSIONS: For Architect HIV Ag/Ab Combo, the FPR is reduced when s/co ratios increase, and the s/co ≥24.44 may be reliable to predict HIV infection.

Degradable Chitosan-Collagen Composites Seeded with Cells as Tissue Engineered Heart Valves.

BACKGROUND: Degradable collagen-chitosan composite materials have been used to fabricate tissue engineered heart valves. The aims of this study were to demonstrate that the collagen-chitosan composite scaffolds are cytocompatible, and endothelial cells can be differentiated from bone marrow mesenchymal stem cells (BMSCs) when seeded onto the scaffolds. The adhesion and biological activities of the seeded cells were also investigated. METHODS: Collagen-chitosan composite material was used as the cell matrix, and smooth muscle cells, fibroblasts and BMSCs were used as seed cells. After four weeks of in vitro culture, the smooth muscle cells, fibroblasts, and BMSCs were sequentially seeded into the collagen-chitosan composite material. After four weeks in culture, the cellular density and activity were assessed on segments of the tissue engineered heart valve scaffolds to determine the cell viability and proliferation in the collagen-chitosan composite material. RESULTS: The tissue engineered heart valves stained positively for both smooth muscle actin and endothelial cell factor VIII, suggesting that the seeded cells were in fact smooth muscle cells, fibroblasts, and endothelial cells. The 6-ketone prostaglandin content, as measured by radioimmunoassay, of the collagen-chitosan cell culture fluid was higher than that of the serum-free medium (P <0.01). Light and electron microscopy showed that the seeded cells had shapes similar to the morphology of smooth muscle cells, fibroblasts, and endothelial cells. CONCLUSIONS: Endothelial cells can be differentiated from BMSCs when seeded onto the collagen-chitosan composite scaffolds. The seeded cells retained their biological activity after being cultured in vitro and seeded into the collagen-chitosan composite material.

HIV infection in Xi'an, China: epidemic characterization, risk factors to false positives and potential utility of the sample-to-cutoff index to identify true positives using Architect HIV Ag/Ab combo.

Background: In China, although tremendous efforts has been made, the HIV/AIDS is still not controlled. Objectives: The study was carried out to determine the epidemic of HIV infection in Xi'an, analyse false positives (FP) risk factors and potential utility of sample-to-cutoff index to identify true positives using Architect HIV Ag/Ab Combo. Methods: A retrospective review for HIV screening by Architect HIV Ag/Ab Combo was performed in a teaching hospital in Xi'an between 2015 and 2016. The prevalence of HIV, positive predictive value (PPV) at different cut-off indexices (COI) were calculated. The epidemic of infections and risk factors for FP results were investigated. Results: In the study, the HIV prevalence and FP rate of Architect HIV Ag/Ab Combo were 0.076 and 46.08%, respectively. The Han Chinese, males and people aged < 40 years accounted for the majority of infections (98.29, 76.07 and 73.5%, respectively). 85.47% of the infections were transmitted through sexual contact (35.04% of male homosexual and 50.43% of heterosexual). COI at 1-10, 10-30 and ≥ 30, the PPVs were 0, 50 and 100%, respectively. The independent risk factors for FP, i.e., pregnancy and malignancy had a statistically significant association with FP (p < 0.05), and age had a very strong statistically significant association with FP (p < 0.001). Conclusions: In Xi'an, sexual contact was the most important transmission mode for HIV, and the infections were predominantly identified in Han Chinese, males, young and middle-aged people. For Architect HIV Ag/Ab Combo, it can achieve 100% of PPV with COI ≥30, and the age was strongly statistically associated with FP.

[Bioinformatics analysis of programmed cell death ligand 1 co-expression genes and their regulatory network in head and neck squamous cell carcinoma].

OBJECTIVE: This study aimed to construct a network of programmed celldeath ligand 1 (PD-L1) co-expression genes and screen potential biomarkers for PD-L1 expression in head and neck squamous cell carcinoma (HNSCC) by bioinformatics analysis. Moreover, the genes and pathways participating in PD-L1 and regulating the tumor immune status were determined. METHODS: The HNSCC transcriptomic dataset in TCGA was selected to retrieve gene sets on the cBioPortal platform, where PD-L1 co-expressional genes were acquired. With these genes, GO-BP, KEGG, and string analyses were performed in R clusterProfiler. Cytoscape was used for network analysis and hub gene screening. RESULTS: A total of 117 co-expression genes were obtained, most of which were enriched in immune regulation and response to viral processes. Node degree analysis indicated that STAT1, IFNG, CXCL10, CCR5, FCGR3A, CXCL9, GBP5, CD86, GZMB, IRF1 were the highest connected genes and functioned as hub genes. Survival analysis of these hub genes resulted in CCR5, CXCL9, and GZMB as the prognostic biomarkers for patients with HNSCC, all of which were involved in immune regulation and their expression levels were related to PD-L1 (Pearson correlation coefficient was 0.30, 0.35, 0.39; P<0.01). High expression levels of these three hub genes were protective factors in patients with HNSCC. CONCLUSIONS: PD-L1 co-expression hub genes are related to immunity, among which CCR5, CXCL9, and GZMB are prognostic markers with the possibility to be involved in programmed cell death protein 1 (PD-1)/PD-L1-induced tumor immune escape. These genes provide new clues to study the mechanism and precision target medicine of PD-1/PD-L1 in HNSCC.

Evaluation of the performance of two tuberculosis interferon gamma release assays (IGRA-ELISA and T-SPOT.TB) for diagnosing Mycobacterium tuberculosis infection.

This data contains information from 3727 patients and shows the performance of two IGRAs tests (T-SPOT.TB and IGRA-ELISA) used in China for screening and diagnostic Mycobacterium tuberculosis infection. The positive results were divided into four groups according with the test values, and the proportions of positives in each group were compared. The positive predictive values (PPVs) at different cutoffs for diagnostic active TB and value change trend for the two IGRAs tests were analyzed.

Evaluation of the performance of two tuberculosis interferon gamma release assays (IGRA-ELISA and T-SPOT.TB) for diagnosing Mycobacterium tuberculosis infection.

OBJECTIVES: The IGRA-ELISA and T-SPOT.TB are widely used in China. The aim of the study was to evaluate the performance of the two assays in diagnosis Mycobacterium tuberculosis infection. METHODS: Of the 3727 patients in the study, 204 underwent testing using both the T-SPOT.TB and IGRA-ELISA, 1794 were tested using the T-SPOT.TB only, and 1729 were tested using the IGRA-ELISA only. The positive rate and consistency of the two assays were analyzed, and their sensitivity and specificity for diagnosing active tuberculosis were compared. RESULTS: There were no significant differences in the positive rate between the T-SPOT.TB test (25.8%) and IGRA-ELISA (28.6%), p = .065. The two assays were highly consistent, with a kappa value of 0.852 (p < .0001) and a total coincidence rate of 92.7%. For the diagnosis of active tuberculosis, the sensitivity and specificity values of the T-SPOT.TB test were 82.9% (107/129) and 78.6% (1309/1665), respectively, and those of IGRA-ELISA were 81.7% (94/115) and 75.2% (1214/1614), respectively. There were no significant differences in sensitivity (p > .05), but the specificity of the T-SPOT.TB test was slightly higher than that of IGRA-ELISA (p = .023). CONCLUSION: Both in terms of diagnosing M. tuberculosis infection and ruling out active tuberculosis, the performance of the IGRA-ELISA-a simple, almost labor-free assay that allows simultaneous processing of a very large number of samples-was well-matched with that of T-SPOT.TB test. However, IGRAs cannot be used as the only test to diagnose active tuberculosis.

[Distribution Characteristics of Air Pollutants and Aerosol Chemical Components Under Different Weather Conditions in Jiaxing].

Distribution characteristics of air pollutants and aerosol chemical components under different weather conditions were investigated in Jiaxing between May 1 and 31, 2015. The particulate matter (PM), gaseous pollutants, chemical components in PM1.0, and aerosol number concentrations ranging from 10 nm to 10 µm were measured using the SHARP-5030 monitoring instrument, Thermo EMS system, Aerodyne Aerosol Chemical Speciation Monitor (ACSM), and Wide-Range Particle Spectrometer (WPS), respectively. The average concentrations of PM2.5, PM1.0, SO2, NO2, O3, and CO were 52.8 µg·m-3, 37.2 µg·m-3, 10.3 µg·m-3, 38.1 µg·m-3, 92.1 µg·m-3, and 1.2 mg·m-3 during the observation period. The chemical components of OA, SO42-, NO3-, NH4+, and Cl-in PM1.0 had average concentrations of 2.18, 1.24, 0.87, 0.63, and 0.08 µg·m-3, respectively. The aerosol number concentrations were mainly centralized in Aitken mode (20-100 nm), with a value of 12411.2 cm-3. The nuclei mode aerosols (10-20 nm) followed the number concentrations with 4946.6 cm-3. The concentration distributions and diurnal variations of PM and gaseous pollutants, and the distributions of chemical components of PM1.0 varied under different weather conditions. The concentrations of chemical components were ranked in the order of OA > SO42- > NO3- > NH4+ > Cl- on rainy days and sunny days, and in the order of OA > NO3- > SO42- > NH4+ > Cl- on new particle formation (NPF) days. The OA and NO3- concentrations on NPF days were 1.61 and 1.42 times larger than those on sunny days, suggesting that the components of OA and NO3- were the main substances influencing the NPF events. Additionally, the diurnal variations of aerosols in different modes varied under different types of weather conditions.

[Dimethylsulfide emission in Qingdao near-shore waters and atmospheric dimethylsulfide concentration variation].

To investigate the emission of dimethylsulfide in near-shore waters seriously disturbed by human activities in China, using the solid absorption-desorption and cryogenic preconcentration method, sampling and analysis of seawater and atmospheric DMS in Qingdao near-shore waters were carried out during 2001-2002. The results showed that the spatial distribution and seasonal variation of seawater DMS concentrations and sea-air fluxes were evident. In summer, the average of seawater DMS concentrations was highest, amounting to 1169.47 ng x L(-1) and lowest in spring, only 226.99 ng x L(-1). The obvious concentration gradient in estuarine, landscape and Olympic Game areas were observed in summer, but in spring and autumn is not so evident. Sea-air flux of DMS was mainly determined by seawater concentration, therefore the sea-air flux coincided with seawater concentration. Average atmospheric DMS concentration was higher in the summer (256.44 ng x m(-3)) and lower in the autumn (195.64 ng x m(-3)). The diurnal variation of atmospheric DMS was discussed in paper.