Enhanced saccharide enrichment in sea spray aerosols by coupling surface-active fatty acids.

The chemical composition of aerosols plays a significant role in aerosol-cloud interactions and, although saccharides make up their largest organic mass fraction, the current process model for understanding sea spray aerosol (SSA) composition struggles to replicate the enrichment of saccharides that has been observed. Here, we simulated the generation of SSA and quantified the enrichment of two soluble saccharides (glucose and trehalose) in SSA with a homemade sea spray aerosol generator. The results of the generation experiments demonstrated that both saccharides, especially trehalose, can promote the generation of SSA, whereas surface-active fatty acids primarily inhibit SSA production due to fewer bubble bursts caused by a large amount of foam accumulation. A significant decrease in surface tension of seawater with the addition of fatty acids was observed, while only a minor decrease was observed for seawater with the addition of only saccharide. Enrichment factors (EFs) of saccharides measured using high performance anion-exchange chromatography (HPAEC) with pulsed amperometric detection (PAD) revealed no enrichment of glucose in submicron SSA, while trehalose showed a slight enrichment. In the presence of surface-active fatty acids on the seawater surface, a significant increase in the enrichment of saccharides in SSA was observed, with glucose and trehalose showing EF of approximately 27-fold and 58-fold, respectively. Besides, this enrichment was accompanied by the accumulation of calcium and magnesium ions. The results presented here suggest that the coupling interaction mechanism of soluble saccharides and surface-active fatty acids on the ocean surface contributes to the enrichment of soluble saccharides in SSA.

Role and Therapeutic Potential for Targeting Fibroblast Growth Factor 10/FGFR1 in Relapsed Rheumatoid Arthritis.

OBJECTIVE: Fibroblast-like synoviocytes (FLSs) contribute to inflammation and joint damage in rheumatoid arthritis (RA). However, the regulatory mechanisms of FLSs in relapse and remission of RA remain unknown. Identifying FLS heterogeneity and their underlying pathogenic roles may lead to discovering novel disease-modifying antirheumatic drugs. METHODS: Combining single-cell RNA sequencing (scRNA-seq) and spatial transcriptomics, we sequenced six matched synovial tissue samples from three patients with relapse RA and three patients in remission. We analyzed the differences in the transcriptomes of the FLS subsets between the relapse and remitted phases. We validated several key signaling pathways using quantitative real-time PCR (qPCR) and multiplex immunohistochemistry (mIHC). We further targeted the critical signals in vitro and in vivo using the collagen-induced arthritis (CIA) model in rats. RESULTS: Lining and sublining FLS subsets were identified using scRNA-seq. Differential analyses indicated that the fibroblast growth factor (FGF) pathway was highly activated in the lining FLSs from patients with relapse RA for which mIHC confirmed the increased expression of FGF10. Although the type I interferon pathway was also activated in the lining FLSs, in vitro stimulation experiment suggested that it was independent of the FGF10 pathway. FGF10 knockdown by small interfering RNA in FLSs significantly reduced the expression of receptor activator of NF-κB ligand. Moreover, recombinant FGF10 protein enhanced bone erosion in the primary human-derived pannus cell culture, whereas the FGF receptor (FGFR) 1 inhibitor attenuated this process. Finally, administering an FGFR1 inhibitor displayed a therapeutic effect in a CIA rat model. CONCLUSION: The FGF pathway is a critical signaling pathway in relapse RA. Targeted tissue-specific inhibition of FGF10/FGFR1 may provide new opportunities to treat patients with relapse RA.

Atmospheric chemical processes of microcystin-LR at the interface of sea spray aerosol.

Microcystins are the most toxic toxins released by cyanobacteria and they have adverse effects on aquatic ecosystems and even human health. Although the removal and detoxification of microcystins in various water bodies have been extensively studied, the interaction mechanism and reaction process of microcystins once they enter the atmosphere are largely unknown, especially at the organic-enriched sea spray aerosol (SSA) interface. Herein, using the surface technique of Langmuir trough coupled in-situ infrared reflection-absorption spectra, we studied the interfacial behavior of microcystin-LR (MC-LR) in artificial seawater containing humic acid and typical surfactants in the presence or absence of UV-irradiation. Zwitterionic 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) and anionic stearic acid (SA) were chosen as typical film-forming species, results obtained from the surface pressure-area isotherms showed that MC-LR caused greater expansion of the DSPC monolayer. The comparable results of MC-LR in DSPC/SA-containing systems indicated that the interaction ability was closely related to the monolayer molecular structure and was regulated by electrostatic interaction. Furthermore, the presence of humic acid (HA) could enhance the interaction between microcystin and monolayer molecules. UV-irradiation experiments showed that the photosensitized reaction greatly promoted the removal of microcystin embedded in the SSA surface compared with the direct photolysis effect in the absence of HA. These findings highlight that the toxic effects of microcystins after entering the atmosphere may be weakened by photochemical reactions.

Unraveling interfacial properties of organic-coated marine aerosol with lipase incorporation.

Marine aerosols are believed to have an organic surface coating on which fatty acids act as an important component due to their high surface activity. In addition, various kinds of enzyme species are abundantly found in seawater, some of which have been identified to exist in marine aerosols. Herein, from the perspective of marine aerosol interface simulation, we investigate the effect of Burkholderia cepacia lipase on the surface properties of stearic acid (SA) monolayer at the air-water interface by using surface-sensitive techniques of Langmuir trough and Infrared reflection-absorption spectroscopy (IRRAS). Our findings indicate that the stearic acid film undergoes a significant expansion, especially when the lipase concentration is 500 nM, because of the incorporation of lipase as observed from the surface pressure-area (π-A) isotherms. IRRAS spectra also show reduced intensities and ordering in the methylene stretching vibration region of stearic acid as a result of low surface density and disordered packing as the enzyme concentration increases. In particular, when the concentration of lipase is 500 nM, the lowest Ias/Is values are shown on both pure water subphase and artificial seawater subphase, indicating more gauche conformations for SA. Furthermore, SA films with lipase incorporation were also studied at three different pH of subphase environment, considering the decrease of pH caused by the reaction with acidic gases during the aerosol aging process. The results reflect a more pronounced expansion of SA monolayer in acidic environment at pH 2.5, suggesting that hydrophobic interaction plays an important role in the disorder of the SA monolayer. In view of the coexistence of fatty acids and enzymes in the marine environment, this study provides a further understanding of the surface organization and behavior of organic-coated marine aerosols and deepen the knowledge of lipid-enzyme interfacial interactions occurring in the atmosphere.

In Situ Generated Plasmonic Silver Nanoparticle-Sensitized Amorphous Titanium Dioxide for Ultrasensitive Photoelectrochemical Sensing of Formaldehyde.

Trace concentration of formaldehyde can damage human health and environment. Consequently, it is of great significance to develop an ultrasensitive sensor for its determination. Herein, an ingenious and efficient photoelectrochemical sensor for formaldehyde was constructed by amorphous TiO2 hollow spheres incorporated with Ag+ ions, which were brought about by silica template etching and then the exchange of Ag+/Na+ ions. The amorphous TiO2 acted the dual role of Ag+ ion probe carriers and photoelectric materials. Upon exposure to the increased concentration of formaldehyde, the Ag nanoparticles were produced in situ, and photocurrent amplification was then achieved in a proportional manner. It is attributed to the injection of hot electrons from plasmonic Ag nanoparticles into the conduction band of amorphous titanium dioxide and therefore enhanced the photocurrent. The linear relationship between 1 and 400 pmol L-1 resulted from the enhanced photocurrent and increased concentration of formaldehyde, and the detection limit was 0.4 pmol L-1. Benefiting from an in situ and unique sensitization strategy, this photoelectrochemical sensor exhibited many advantages such as sensitivity, selectivity, cost-effectiveness, convenience of fabrication, low power consumption, and stability.