Biogenic emission as a potential source of atmospheric aromatic hydrocarbons: Insights from a cyanobacterial bloom-occurring eutrophic lake.

As important precursors of ozone (O3) and secondary organic aerosol (SOA), reactive aromatic hydrocarbons (AHs) have typically been classified as anthropogenic air pollutants. However, biogenic emission can also be a potential source of atmospheric AHs. Herein, field observations in a eutrophic lake were combined with laboratory incubation experiments to investigate the biogenic AH emission. Field work showed that the water-air fluxes of AHs measured at sites with high cyanobacteria abundance could reach an order of magnitude greater than those at sites with low cyanobacteria abundance, suggesting that cyanobacteria could be the important contributor to measured AHs. Laboratory incubation experiments further confirmed the AH emission of cyanobacteria and revealed that the emission could change significantly over the lifespan of cyanobacteria and varied to their growing conditions. By combining field observations and laboratory incubation experiments, it has been suggested that the emission of different AH species from cyanobacteria could be modulated by variable biogeochemical mechanisms and that the biochemical process of toluene could be different from that of other AHs. This study investigates AH emissions from inland aquatic ecosystem and suggests that biogenic emission could be a potential source of atmospheric AHs.

A comparative study on the formation of nitrogen-containing organic compounds in cloud droplets and aerosol particles.

Nitrogen-containing organic compounds (NOCs) may potentially contribute to aqueous secondary organic aerosols, yet the different formation of NOCs in aerosol particles and cloud droplets remains unclear. With the in-situ measurements performed at a mountain site (1690 m a.s.l.) in southern China, we investigated the formation of NOCs in the cloud droplets and the cloud-free particles, based on their mixing state information of NOCs-containing particles by single particle mass spectrometry. The relative abundance of NOCs in the cloud-free particles was significantly higher than those in cloud residual (cloud RES) particles. NOCs were highly correlated with carbonyl compounds (including glyoxalate and methylglyoxal) in the cloud-free particles, however, limited correlation was observed for cloud RES particles. Analysis of their mixing state and temporal variations highlights that NOCs was mainly formed from the carbonyl compounds and ammonium in the cloud-free particles, rather than in the cloud RES particles. The results support that the formation of NOCs from carbonyl compounds is facilitated in concentrated solutions in wet aerosols, rather than cloud droplets. In addition, we have identified the transport of biomass burning particles that facilitate the formation of NOCs, and that the observed NOCs is most likely contributed to the light absorption. These findings have implications for the evaluation of NOCs formation and their contribution to light absorption.

Administration of Lactobacillus plantarum GUANKE alleviates SARS-CoV-2-induced pneumonia in mice.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) targets epithelial cells in the respiratory tract, triggering an acute proinflammatory response and chronic lung inflammation. Probiotic supplementation has shown promise in reducing the nasopharyngeal SARS-CoV-2 viral load, diminishing symptom frequency and duration, and mitigating inflammation; thus, it is a potential strategy for treating coronavirus disease 2019 (COVID-19), which is caused by SARS-CoV-2 infection. In this study, we evaluated the effects of the oral administration of the Lactobacillus plantarum GUANKE strain, a gram-positive bacterium originally isolated from a healthy individual, on SARS-CoV-2 infection in a human ACE2 transgenic mouse model. We found that GUANKE significantly reduced inflammatory cell infiltration and pulmonary interstitial exudation in mice. The transcription of CCL2, TNFA, IL1B, IL6, and IL17C in the lungs was reduced. The protein levels of TNF-α, IL-1ß, IL-6, and IL-17 in the lungs were significantly lower in GUANKE-treated mice than in control mice. The viral load in GUANKE-treated mice was lower than that in saline-treated mice, although this difference did not reach statistical significance. L. plantarum GUANKE can decrease SARS-CoV-2-induced lung inflammation in mice, suggesting its potential for use as an agent for treating SARS-CoV-2 infection. IMPORTANCE: Most otherwise healthy individuals develop only mild or moderate symptoms of coronavirus disease 2019 (COVID-19) caused by current strains of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and virus replication is mainly confined to the upper respiratory tract; however, the virus can infect the lower respiratory tract and promote inflammation. Probiotic supplementation has been shown to reduce nasopharyngeal SARS-CoV-2 viral load, reduce the overall number and duration of symptoms, and attenuate inflammation in clinical trials. We showed that a novel L. plantarum GUANKE strain alleviated SARS-CoV-2-induced pneumonia in mice. The transcription and production of inflammatory cytokines were suppressed, and GUANKE moderately reduced the viral load. L. plantarum GUANKE has the potential to become a candidate drug for the treatment of COVID-19 or other viral respiratory infections.

On the contribution of atmospheric reactive nitrogen deposition to nitrogen burden in a eutrophic Lake in eastern China.

Although it has been demonstrated that atmospheric reactive nitrogen (i.e., Nr mainly including NH3, NH4+, NOx, NO3- and etc.) deposition has substantial impacts on nitrogen pools in remote and/or sensitive lakes, there is a scarcity of systematic evaluations regarding the impact on nitrogen burden in eutrophic lakes with riverine input as primary nitrogen source. Utilizing a regional atmospheric chemical transport model, combined with observation-based estimates of atmospheric nitrogen deposition fluxes and riverine nitrogen inputs, we investigate the contribution of atmospheric Nr deposition to the fifth largest freshwater lake located in eastern China, i.e., the Chaohu Lake which is facing frequent outbreaks of algal bloom. The results indicate that in the studied year of 2022, riverine total nitrogen (TN) input to the lake was 11553.3 t N yr-1 and atmospheric TN deposition was 2326.0 t N yr-1. For Nr species which are directly available for the biosphere supporting algae and plant growth, riverine NH4+ input was 1856.1 t N yr-1 and atmospheric NHx (NH3 and NH4+) deposition was 824.5 t N yr-1. The latter accounts for 30.8% of total NHx input to the lake. For NOy (HNO3 and NO3-), riverine NO3- input was estimated as 2621.7 t N yr-1, while atmospheric NOy deposition was 629.3 t N yr-1, accounting for 19.4%. In all, atmospheric Nr deposition accounts for 24.5 % of total Nr input to the lake. Our results suggest that even in regions with dense human activities with primary riverine N input, atmospheric deposition of Nr could also contribute significantly to the bio-available nitrogen in lake systems, and addressing eutrophication in Lake Chaohu and other eutrophic lakes will also need to consider the influence of atmospheric Nr deposition which is related to NH3 and NOx (i.e., NO + NO2, the precursor of NOy) emissions, in addition to the mitigation of riverine N input.

[Analysis of Ozone Pollution and Precursor Control Strategies in the Pearl River Delta During Summer and Autumn Transition Season].

To analyze the causes of ozone pollution in the Pearl River Delta （PRD） Region during the summer and autumn transition seasons, a case study was carried out in Guangzhou, which is located in the center of the PRD Region, to analyze the ozone photochemical production and destruction pathways as well as emission reduction scenarios using a box model based on comprehensive observation. The results showed that the stagnant meteorological conditions and high temperature during the observation period were suitable for the photochemical production of ozone, which led to widespread and prolonged ozone pollution. Aromatic hydrocarbons （AHs） contributed the most to the ozone formation potential （OFP）, and m/p-xylene, toluene, and o-xylene were the major three VOC species contributing to the OFP. Box model analysis revealed that the averaged net O3 production rate during the polluted period was 23.2×10-9 h-1 and the peak reached 39.2×10-9 h-1. The HO2·+NO and NO2+·OH reaction pathways contributed the most to the local photochemical ozone production （51.2%） and destruction （47.0%）, respectively. Observed ozone concentration was primarily controlled by both the local photochemical O3 production and the export-dominated transport. The RIR and EKMA analyses showed that O3 formation in Guangzhou during the summer-autumn transition seasons was mainly a VOC-limited regime and AHs showed the greatest sensitivity to O3 production. Toluene, m/p-xylene, o-xylene, n-butane, and propylene were the five key components affecting O3 generation. The analysis of reduction scenarios showed that reducing anthropogenic VOC emissions was the most favorable way to reduce O3 concentrations； however, if NOx emission was controlled after reducing VOCs, the O3 concentration would rebound in a short time. Our results suggested that the synergistic reduction of VOCs and NOx while mainly focusing on VOCs alleviation should be implemented to continuously reduce ozone concentrations in the future.

Dominant Contribution of Non-dust Primary Emissions and Secondary Processes to Dissolved Aerosol Iron.

Solubility largely determines the impacts of aerosol Fe on marine ecosystems and human health. Currently, modeling studies have large uncertainties in aerosol Fe solubility due to inadequate understanding of the sources of dissolved Fe. This work investigated seasonal variations of Fe solubility in coarse and fine aerosols in Qingdao, a coastal city in the Northwest Pacific, and utilized a receptor model for source apportionment of total and dissolved aerosol Fe. Desert dust was found to be the main source of total Fe, contributing 65 and 81% annually to total Fe in coarse and fine particles, respectively; in contrast, dissolved aerosol Fe originated primarily from combustion, industrial, and secondary sources. The annual average contributions to dissolved Fe in coarse and fine particles were 68 and 47% for the secondary source and 32 and 33% for the combustion source, respectively. Aerosol Fe solubility was found to be highest in summer and lowest in spring, showing seasonal patterns similar to those of aerosol acidity. Increase in Fe solubility in atmospheric particles, when compared to desert dust, was mainly caused by secondary processing and combustion emission, and the effect of secondary processes was dictated by aerosol acidity and liquid water content.

Impact of corticosteroids on initiation and half-year durability of humoral response in COVID-19 survivors.

Background: The impact of corticosteroids on humoral responses in coronavirus disease 2019 (COVID-19) survivors during the acute phase and subsequent 6-month period remains unknown. This study aimed to determine how the use of corticosteroids influences the initiation and duration of humoral responses in COVID-19 survivors 6 months after infection onset. Methods: We used kinetic antibody data from the lopinavir-ritonavir trial conducted at Jin Yin-Tan Hospital in January 2020, which involved adults hospitalized with severe COVID-19 (LOTUS, ChiCTR2000029308). Antibody samples were collected from 192 patients during hospitalization, and kinetic antibodies were monitored at all available time points after recruitment. Additionally, plasma samples were collected from 101 COVID-19 survivors for comprehensive humoral immune measurement at the half-year follow-up visit. The main focus was comparing the humoral responses between patients treated with systemic corticosteroid therapy and the non-corticosteroid group. Results: From illness onset to day 30, the median antibody titre areas under the receiver operating characteristic curve (AUCs) of nucleoprotein (N), spike protein (S), and receptor-binding domain (RBD) immunoglobulin G (IgG) were significantly lower in the corticosteroids group. The AUCs of N-, S-, and RBD-IgM as well as neutralizing antibodies (NAbs) were numerically lower in the corticosteroids group compared with the non-corticosteroid group. However, peak titres of N, S, RBD-IgM and -IgG and NAbs were not influenced by corticosteroids. During 6-month follow-up, we observed a delayed decline for most binding antibodies, except N-IgM (ß -0.05, 95% CI [-0.10, 0.00]) in the corticosteroids group, though not reaching statistical significance. No significant difference was observed for NAbs. However, for the half-year seropositive rate, corticosteroids significantly accelerated the decay of IgA and IgM but made no difference to N-, S-, and RBD-IgG or NAbs. Additionally, corticosteroids group showed a trend towards delayed viral clearance compared with the non-corticosteroid group, but the results were not statistically significant (adjusted hazard ratio 0.71, 95% CI 0.50-1.00; P = 0.0508). Conclusion: Our findings suggested that corticosteroid therapy was associated with impaired initiation of the antibody response but this did not compromise the peak titres of binding and neutralizing antibodies. Throughout the decay phase, from the acute phase to the half-year follow-up visit, short-term and low-dose corticosteroids did not significantly affect humoral responses, except for accelerating the waning of short-lived antibodies.

Positive feedback loop PU.1-IL9 in Th9 promotes rheumatoid arthritis development.

OBJECTIVES: T helper 9 (Th9) cells are recognised for their characteristic expression of the transcription factor PU.1 and production of interleukin-9 (IL-9), which has been implicated in various autoimmune diseases. However, its precise relationship with rheumatoid arthritis (RA) pathogenesis needs to be further clarified. METHODS: The expression levels of PU.1 and IL-9 in patients with RA were determined by ELISA, western blotting (WB) and immunohistochemical staining. PU.1-T cell-conditional knockout (KO) mice, IL-9 KO and IL-9R KO mice were used to establish collagen antibody-induced arthritis (CAIA), respectively. The inhibitor of PU.1 and IL-9 blocking antibody was used in collagen-induced arthritis (CIA). In an in vitro study, the effects of IL-9 were investigated using siRNAs and IL-9 recombinant proteins. Finally, the underlying mechanisms were further investigated by luciferase reporter analysis, WB and Chip-qPCR. RESULTS: The upregulation of IL-9 expression in patients with RA exhibited a positive correlation with clinical markers. Using CAIA and CIA model, we demonstrated that interventions targeting PU.1 and IL-9 substantially mitigated the inflammatory phenotype. Furthermore, in vitro assays provided the proinflammatory role of IL-9, particularly in the hyperactivation of macrophages and fibroblast-like synoviocytes. Mechanistically, we uncovered that PU.1 and IL-9 form a positive feedback loop in RA: (1) PU.1 directly binds to the IL-9 promoter, activating its transcription and (2) Th9-derived IL-9 induces PU.1 via the IL-9R-JAK1/STAT3 pathway. CONCLUSIONS: These results support that the PU.1-IL-9 axis forms a positive loop in Th9 dysregulation of RA. Targeting this signalling axis presents a potential target approach for treating RA.

Short-chain fatty acids regulate erastin-induced cardiomyocyte ferroptosis and ferroptosis-related genes.

Background: Ferroptosis has been proven to contribute to the progression of myocardial ischemia/reperfusion (I/R) injury and can be inhibited or promoted by ATF3. Short-chain fatty acids (SCFAs) have shown benefits in various cardiovascular diseases with anti-inflammatory and antioxidant effects. However, the impact of SCFAs on ferroptosis in ischemic-stimulated cardiomyocytes remains unknown. This study aimed to investigate the effect of SCFAs on cardiomyocyte ferroptosis, the expression of ATF3, and its potential upstream regulators. Methods and results: The expression of ATF3, ferroptosis pathway geneset (FPG), and geneset of potential regulators for ATF3 (GPRA, predicted by the PROMO database) was explored in the public human myocardial infarction single-cell RNA-seq (sma) dataset. Cardiomyocyte data was extracted from the dataset and re-clustered to explore the FPG, ATF3, and GPRA expression patterns in cardiomyocyte subclusters. A dose-dependent toxic experiment was run to detect the suitable dose for SCFA treatment. The erastin-induced ferroptosis model and hypoxia-reoxygenation (H/R) model (10 h of hypoxia followed by 6 h of reoxygenation) were adopted to assess the effect of SCFAs via the CCK8 assay. Gene expression was examined via RT-PCR and western blot. Ferroptosis markers, including lipid peroxides and Fe2+, were detected using the liperfluo and ferroOrange probes, respectively. In the sma dataset, upregulated ferroptosis pathway genes were mainly found in the infarction-stimulated cardiac cells (border zone and fibrotic zone), particularly the cardiomyocytes and adipocytes. The ATF3 and some of its potential transcription factors (VDR, EGR3, PAX5, and SP1) can be regulated by SCFA. SCFA can attenuate erastin-induced lipid peroxidation in cardiomyocytes. SCFA treatment can also reverse erastin-induced Fe2+ increase but may strengthen the Fe2+ in the H/R model. We also precisely defined a ferroptosis subcluster of cardiomyocytes (CM09) that highly expressed FPG, ATF3, and GPRA. Conclusion: The ATF3 and the ferroptosis pathway are elevated in cardiomyocytes of injury-related cardiac regions (border zone, ischemic zone, and fibrotic zone). SCFA can attenuate cardiomyocyte ferroptosis and regulate the expression of ATF3. Our study offers novel insights into the potential targets of SCFAs in the cardiovascular system.

Infection­associated bile acid disturbance contributes to macrophage activation in patients with cirrhosis.

Cirrhosis impairs macrophage function and disrupts bile acid homeostasis. Although bile acids affect macrophage function in patients with sepsis, whether and how the bile acid profile is changed by infection in patients with cirrhosis to modulate macrophage function remains unclear. The present study aimed to investigate the changes in the bile acid profile of patients with cirrhosis and infection and their effects on macrophage function. Serum was collected from 20 healthy subjects, 18 patients with cirrhosis and 39 patients with cirrhosis and infection. Bile acid profiles were detected using high­performance liquid chromatography­triple time­of­flight mass spectrometer. The association between bile acid changes and infection was analysed using receiver operating characteristic (ROC) curves. Infection­altered bile acids were used in combination with lipopolysaccharides (LPS) to stimulate RAW264.7/THP­1 cells in vitro. The migratory capacity was evaluated using wound healing and Transwell migration assays. The expression of Arg­1, iNOS, IκBα, phosphorylated (p­)IκBα and p65 was examined with western blotting and immunofluorescence, Tnfα, Il1b and Il6 mRNA was examined with RT­qPCR, and CD86, CD163 and phagocytosis was measured with flow cytometry. The ROC curves showed that decreased hyodeoxycholic acid (HDCA) and deoxycholic acid (DCA) levels were associated with infection. HDCA or DCA combined with LPS enhanced the phagocytic and migratory ability of macrophages, accompanied by upregulation of iNOS and CD86 protein expression as well as Tnfα, Il1b, and Il6 mRNA expression. However, neither HDCA nor DCA alone showed an effect on these phenotypes. In addition, DCA and HDCA acted synergistically with LPS to increase the expression of p­IκBα and the intranuclear migration of p65. Infection changed the bile acid profile in patients with cirrhosis, among which the reduction of DCA and HDCA associated most strongly with infection. HDCA and DCA enhanced the sensitivity of macrophage function loss to LPS stimulation. These findings suggested a potential role for monitoring the bile acid profile that could help manage patients with cirrhosis and infection.

A Dual-Modal, Label-Free Raman Imaging Method for Rapid Virtual Staining of Large-Area Breast Cancer Tissue Sections.

As one of the most common cancers, accurate, rapid, and simple histopathological diagnosis is very important for breast cancer. Raman imaging is a powerful technique for label-free analysis of tissue composition and histopathology, but it suffers from slow speed when applied to large-area tissue sections. In this study, we propose a dual-modal Raman imaging method that combines Raman mapping data with microscopy bright-field images to achieve virtual staining of breast cancer tissue sections. We validate our method on various breast tissue sections with different morphologies and biomarker expressions and compare it with the golden standard of histopathological methods. The results demonstrate that our method can effectively distinguish various types and components of tissues, and provide staining images comparable to stained tissue sections. Moreover, our method can improve imaging speed by up to 65 times compared to general spontaneous Raman imaging methods. It is simple, fast, and suitable for clinical applications.

Profiling of viral load, antibody and inflammatory response of people with monkeypox during hospitalization: a prospective longitudinal cohort study in China.

BACKGROUND: The dynamics of viral shedding and the specific humoral response against monkeypox virus (MPXV) have not been well characterized in patients across their disease course during hospitalisation. The aim of this study was to determine the viral load and the levels of antibodies against MPXV using longitudinal paired-collected samples from hospitalized patients. METHODS: Patients who were hospitalised with mpox were recruited at Beijing Ditan Hospital Capital Medical University in China between June 2 and September 23, 2023. Paired samples, including samples from skin lesions, the oropharynx, saliva, faeces, urine, plasma, and serum, were serially collected at days 1, 3, 7, and 14 after admission until discharge. Not all of the patients had samples obtained at all of the timepoints. All the samples were analysed via quantitative PCR. Virus isolation was performed by using clinical samples and Vero cells. The presence of IgM, IgA, IgG, and neutralising antibodies (NAbs) against MPXV was evaluated. The first collected plasma sample was taken when the patient was hospitalised, and the levels of cytokines and chemokines were measured in the sample. The demographic data, smallpox vaccination status, history of known exposure to MPVX, HIV status and other clinical data were collected using a standard case report form. FINDINGS: A total of 510 specimens were serially collected from 39 recruited people with mpox. Among all the samples, the skin lesions had the highest viral DNA detection rates and viral loads, and the saliva samples had the second highest rates and viral loads. One day before discharge, 85% of the dry scrabs (median Ct 28.2, range 19.0-38.3) and 70% of the saliva samples (median Ct 32.4, range 24.5-38.1) were positive for viral DNA, Of which, 23.1% of dry scrabs were positive in viral culture. The rate of viral DNA detection in the oropharyngeal, saliva, and faecal samples decreased with time, while the rates in the plasma, serum, and urine samples increased quickly before 10 days post symptom onset (PSO). The median days of appearance of MPXV-IgM, MPXV-IgA, MPXV-IgG, and NAb were at 8 (interquartile range [IQR] 7-9), 9 (7-10), 12 (9-15), and 12 (9-15) PSO, respectively. The IgM, IgA, IgG, and NAb titres increased with time. Between days 11 and 21 PSO, the NAb titres were lower in people living with HIV (PWH) than in people living without HIV (PWOH). Increased NAb titres were associated with decreased viral loads in the saliva (r = 0.28, p = 0.025), faeces (r = 0.35, p = 0.021), plasma (r = 0.30, p = 0.0044), and serum samples (r = 0.37, p = 0.001). Compared with PWOH, PWH had higher plasma levels of MIP-1α, MIP-1ß, G-CSF, IL-4, and FGF-basic. INTERPRETATION: The high positive viral culture rate of clinical samples of patients when they are discharged from the hospital indicates that effective public health management strategies are needed for people with mpox. The low NAb titres and high levels of cytokines in PWH shows that earlier treatment is needed to control inflammation in high-risk populations. FUNDING: National Natural Science Foundation of China, Chinese Academy of Medical Sciences, Fundamental Research Funds for the Central Universities for Peking Union Medical College, National Key R&D Program of China.

Characterization of biomass burning tracers in particulate matter at 12 sites in China: Significant increase of coal combustion emitted levoglucosan in northern China during winter.

Biomass burning (BB) is the largest contributor to carbonaceous aerosols globally. Specific organic tracers can track BB particles and identify BB types. At present, there is limited information on the composition of BB tracers on a continental scale. In this study, we conducted year-round sampling of particulate matter (PM) at 12 sites in China. Nine BB tracers were measured in PM with aerodynamic diameters <1.1 µm (PM<1.1), in the range of 1.1-3.3 µm (PM1.1-3.3), and > 3.3 µm (PM>3.3). The annual average concentration of these nine BB tracers (∑9 BB tracers) in the total PM was 366 ng m-3 with the majority of levoglucosan (66 %). The concentration of ∑9 BB tracers was higher in northern China than in southern China, especially in winter. ∑9 BB tracers were most enriched in PM<1.1 (50-61 % in mass), followed by PM1.1-3.3 and PM>3.3. The highest concentrations of ∑9 BB tracers were observed in winter, while satellite-recorded fire spots were intensive in autumn and spring. The mismatch of seasonal trends between them indicated that the high levels of BB tracers in winter was not due to open BB. The composition of 4-hydroxybenzoic acid, syringic acid and vanillic acid suggested that the burning of crop residues and softwoods were the major BB types in China. The ratio of levoglucosan to mannosan could neither identify the major BB types in China nor distinguish between BB and coal combustion. Correlation analysis and the PMF model demonstrated that non-BB sources contributed 7 %-58 % to levoglucosan at the 12 sites, with coal combustion being the predominant non-BB source in China, especially in northern urban sites during winter. Our findings suggest that caution should be taken in application of these organic tracers to identify BB types and estimate BB aerosols.

Polyoxometalate-derived electrocatalysts enabling progress in hydrogen evolution reactions.

Platinum-based catalysts exhibit outstanding electrocatalytic performance in the hydrogen evolution reaction (HER). However, platinum-based catalysts face significant challenges due to their rarity and high cost. This paper endeavors to shed light on a promising alternative: polyoxometalate (POM)-based catalysts, which possess significant potential for the synthesis of non-noble metal-based catalysts for the HER. Utilizing POMs as raw materials to assemble POM-derived materials, including POM-derived crystalline materials, metal sulfides, phosphides, carbides, nitrides, and so on, has emerged as an effective approach for the synthesis of hydrogen evolution electrocatalysts. This approach offers advantages in both stability and electrocatalytic performance. This comprehensive review navigates through latest progress in the assembly strategy and HER performance of POM-based crystal materials, alongside discussion on transition metal compounds derived from POMs, such as carbides, phosphides, and sulfides. Besides, future developments in POM-derived electrocatalyst regulation of the electrochemical HER are prospected.

Observation-Based Diagnostics of Reactive Nitrogen Recycling through HONO Heterogenous Production: Divergent Implications for Ozone Production and Emission Control.

Understanding of nitrous acid (HONO) production is crucial to photochemical studies, especially in polluted environments like eastern China. In-situ measurements of gaseous and particulate compositions were conducted at a rural coastal site during the 2018 spring Ozone Photochemistry and Export from China Experiment (OPECE). This data set was applied to investigate the recycling of reactive nitrogen through daytime heterogeneous HONO production. Although HONO levels increase during agricultural burning, analysis of the observation data does not indicate more efficient HONO production by agricultural burning aerosols than other anthropogenic aerosols. Box and 1-D modeling analyses reveal the intrinsic relationships between nitrogen dioxide (NO2), particulate nitrate (pNO3), and nitric acid (HNO3), resulting in comparable agreement between observed and simulated HONO concentrations with any one of the three heterogeneous HONO production mechanisms, photosensitized NO2 conversion on aerosols, photolysis of pNO3, and conversion from HNO3. This finding underscores the uncertainties in the mechanistic understanding and quantitative parametrizations of daytime heterogeneous HONO production pathways. Furthermore, the implications for reactive nitrogen recycling, ozone (O3) production, and O3 control strategies vary greatly depending on the HONO production mechanism. On a regional scale, the conversion of HONO from pNO3 can drastically enhance O3 production, while the conversion from NO2 can reduce O3 sensitivity to NOx changes in polluted eastern China.

Laboratory studies on the infectivity of human respiratory viruses: Experimental conditions, detections, and resistance to the atmospheric environment.

The environmental stability of infectious viruses in the laboratory setting is crucial to the transmission potential of human respiratory viruses. Different experimental techniques or conditions used in studies over the past decades have led to diverse understandings and predictions for the stability of viral infectivity in the atmospheric environment. In this paper, we review the current knowledge on the effect of simulated atmospheric conditions on the infectivity of respiratory viruses, mainly focusing on influenza viruses and coronaviruses, including severe acute respiratory syndrome coronavirus 2 and Middle East respiratory syndrome coronavirus. First, we summarize the impact of the experimental conditions on viral stability; these involve the methods of viral aerosol generation, storage during aging and collection, the virus types and strains, the suspension matrixes, the initial inoculum volumes and concentrations, and the drying process. Second, we summarize and discuss the detection methods of viral infectivity and their disadvantages. Finally, we integrate the results from the reviewed studies to obtain an overall understanding of the effects of atmospheric environmental conditions on the decay of infectious viruses, especially aerosolized viruses. Overall, this review highlights the knowledge gaps in predicting the ability of viruses to maintain infectivity during airborne transmission.

Adhesion and Transparency Enhancement between Flexible Polyimide-PDMS Copolymerized Film and Copper Foil for LED Transparent Screen.

With the increasing demand for innovative electronic products, LED transparent screens are gradually entering the public eye. Polyimide (PI) materials combine high temperature resistance and high transparency, which can be used to prepare flexible copper-clad laminate substrates. The physical and chemical properties of PI materials differ from copper, such as their thermal expansion coefficients (CTEs), surface energy, etc. These differences affect the formation and stability of the interface between copper and PI films, resulting in a short life for LED transparent screens. To enhance PI-copper interfacial adhesion, aminopropyl-terminated polydimethylsiloxane (PDMS) can be used to increase the adhesive ability. Two diamine monomers with a trifluoromethyl structure and a sulfone group structure were selected in this research. Bisphenol type A diether dianhydride is a dianhydride monomer. All three of the above monomers have non-coplanar structures and flexible structural units. The adhesion and optical properties can be improved between the interface of the synthesized PI films and copper foil. PI films containing PDMS 0, 1, 3, and 5 wt% were analyzed using UV spectroscopy. The transmittance of the PI-1/3%, PI-1/5%, PI-2/3%, and PI-2/5% films were all more than 80% at 450 nm. Meanwhile, the Td 5% and Td 10% heat loss and Tg temperatures decreased gradually with the increase in PDMS. The peel adhesion of PI-copper foil was measured using a 180° peel assay. The effect of PDMS addition on peel adhesion was analyzed. PIs-3% films had the greatest peeling intensities of 0.98 N/mm and 0.85 N/mm.

Enhanced performance of a Na3.5Co4[Bi2Co2W19.75O70(H2O)6]/porous graphitic carbon nitride heterojunction based photocatalyst realized by the addition of copper sulfide nanoparticles.

Photocatalytic hydrogen (H2) evolution can effectively solve the global energy problem, in which the key factor is the synthesis of efficient photocatalytic materials. In this study, we successfully synthesized a novel photocatalyst, BiWCo/CuS/PGCN, by functionalizing porous graphitic carbon nitride (PGCN) with sandwich-type polyoxometalate Na3.5Co4[Bi2Co2W19.75O70(H2O)6]·39.5H2O (BiWCo) and introducing copper sulfide (CuS) nanoparticles as a cocatalyst. This approach was aimed at enhancing the built inner electric field between interfaces, resulting in a significant improvement in photocatalytic H2 evolution performance. This research adopts a step-by-step method to synthesize BiWCo/CuS/PGCN composites with p-n heterojunctions, which has high visible light absorption and a synergistic effect of multiple elements. PGCN with a high specific surface area contributes to the uniform distribution of active sites. In addition, the nano-CuS cocatalyst provides abundant active sites and more electron transfer pathways for photocatalysis. Therefore, the H2 production efficiency of BiWCo/CuS/PGCN is 6.3 times that of PGCN, 4.5 times that of BiWCo and 2.5 times that of BiWCo/PGCN under visible light. The H2 production rate of BiWCo/CuS/PGCN reaches 3477.58 µmol g-1 h-1. At the same time, the ternary photocatalyst shows high stability after 30 hours and 5 cycles. This work demonstrates that BiWCo/CuS/PGCN has good application prospects in H2 evolution, and provides a new strategy for the design of efficient ternary photocatalytic materials.

Highly diverse sputum microbiota correlates with the disease severity in patients with community-acquired pneumonia: a longitudinal cohort study.

BACKGROUND: Community-acquired pneumonia (CAP) is a common and serious condition that can be caused by a variety of pathogens. However, much remains unknown about how these pathogens interact with the lower respiratory commensals, and whether any correlation exists between the dysbiosis of the lower respiratory microbiota and disease severity and prognosis. METHODS: We conducted a retrospective cohort study to investigate the composition and dynamics of sputum microbiota in patients diagnosed with CAP. In total, 917 sputum specimens were collected consecutively from 350 CAP inpatients enrolled in six hospitals following admission. The V3-V4 region of the 16 S rRNA gene was then sequenced. RESULTS: The sputum microbiota in 71% of the samples were predominately composed of respiratory commensals. Conversely, 15% of the samples demonstrated dominance by five opportunistic pathogens. Additionally, 5% of the samples exhibited sterility, resembling the composition of negative controls. Compared to non-severe CAP patients, severe cases exhibited a more disrupted sputum microbiota, characterized by the highly dominant presence of potential pathogens, greater deviation from a healthy state, more significant alterations during hospitalization, and sparser bacterial interactions. The sputum microbiota on admission demonstrated a moderate prediction of disease severity (AUC = 0.74). Furthermore, different pathogenic infections were associated with specific microbiota alterations. Acinetobacter and Pseudomonas were more abundant in influenza A infections, with Acinetobacter was also enriched in Klebsiella pneumoniae infections. CONCLUSION: Collectively, our study demonstrated that pneumonia may not consistently correlate with severe dysbiosis of the respiratory microbiota. Instead, the degree of microbiota dysbiosis was correlated with disease severity in CAP patients.