Search

Background: The unrelenting emergence of SARS-CoV-2 variants has significantly challenged the efficacy of existing COVID-19 vaccines. Enhancing the stability and immunogenicity of the spike protein is critical for improving vaccine performance and addressing variant-driven immune evasion. Methods: We developed an mRNA-based vaccine, RV-1730, encoding the Delta variant spike protein with the S6P mutation to enhance stability and immunogenicity. The vaccine's immunogenicity and protective efficacy were evaluated in preclinical models, including monovalent (RV-1730) and bivalent (RV-1731) formulations targeting the Delta and BA.1 variants. Additionally, the effectiveness of RV-1730 as a heterologous booster following primary vaccination with BNT162b2 (Pfizer-BioNTech) and mRNA-1273 (Moderna-NIAID) was assessed. Results: RV-1730 elicited significantly stronger B and T cell responses and more durable neutralizing antibodies compared to S2P-based vaccines. The bivalent RV-1731 vaccine demonstrated broad neutralizing activity against emerging variants, including XBB1.5 and JN.1. Importantly, RV-1730, when used as a heterologous booster following initial immunization with BNT162b2 or mRNA-1273, significantly enhanced neutralizing antibody titers against multiple variants, including Delta and Omicron. Both RV-1730 and RV-1731 provided superior protection in preclinical models, indicating enhanced efficacy due to the S6P mutation. Conclusion: The incorporation of the S6P mutation into the Delta variant spike protein significantly enhances the immunogenicity and efficacy of mRNA-based COVID-19 vaccines. The strong performance of RV-1730 as a heterologous booster and the broad-spectrum activity of the bivalent RV-1731 vaccine underscore their potential as versatile and effective vaccination strategies against SARS-CoV-2 and its evolving variants. [ABSTRACT FROM AUTHOR]

The physicochemical properties and origins of atmospheric aerosols in the Tibetan Plateau (TP) region are a research topic of great interest, but an in‐depth understanding of this topic is challenging, partially due to a lack of intensive in situ observations. Thus, a field campaign was conducted over Yadong, a remote area on the south slope of the TP from June 11 to 31 August 2021. The aerosol loading was low, with a black carbon mass concentration of 147.4 ± 98.4 ng·m−3. Aerosol single‐scattering albedo was low (0.73 ± 0.11 at 550 nm) and increased from 450 to 700 nm wavelength. Organic matter (OM) accounting for 69.6% of the total aerosol mass and relatively high secondary organic carbon ratios, highlighting the importance of secondary formation. An interesting phenomenon observed was that the evolution of aerosols was mainly characterized by diurnal variation, which could not be explained by large‐scale atmospheric processes such as Indian summer monsoon. Instead, it was found that regional mountain‐valley winds between the Himalayas and South Asia transported polluted air masses toward the TP, especially in the afternoon when regional valley wind are expected to be the strongest and the boundary layer in South Asia is deepest. Additionally, daytime local valley wind further elevated these aerosols to higher altitudes on the TP. This paper provides insights into the transport mechanisms of aerosols from South Asia to the TP. These findings are of great importance since aerosols exhibit significant diurnal variations in the TP region. Plain Language Summary: Previous studies focused on the analysis of the physical or chemical properties of aerosols on the Tibetan Plateau, but this study provides a comprehensive examination of both. The findings reveal that aerosols on the southern slope of the Tibetan Plateau exhibit strong absorption efficiency. Aerosol single‐scattering albedo was low (0.73 ± 0.11 at 550 nm), which may be attributed to aerosol secondary generation and coating. Finally, the mechanism of pollutant transport from South Asia to the Tibetan Plateau was analyzed relies on site observations, satellite, and reanalysis data to highlight the link between diurnal variations of pollutants and transport mechanism. The specific transport mechanism be understood uniformly across different scales, including Indian summer monsoon, regional mountain‐valley winds between the Himalayas and South Asia, and local mountain‐valley winds circulation. Key Points: Aerosol single‐scattering albedo was low (0.73 ± 0.11 at 550 nm) and secondary organic matter was the major aerosol componentThe evolution of aerosols was mainly characterized by diurnal variation that was related to transport mechanism over YadongThe Himalayas‐South Asia regional mountain‐valley winds combined with local mountain‐valley winds transport aerosols to the Tibetan Plateau [ABSTRACT FROM AUTHOR]

The region surrounding the Tibetan Plateau (TP) is widely considered a primary global dust source, with mineral dust comprising a significant proportion of aerosols over the TP. Current research on TP dust has mainly focused on transport from the surrounding deserts, with little focus on dust emissions from the TP's interior. The erodibility factor used by the WRF‐Chem (ERODDEF) is 0 for the TP, so the model cannot simulate the dust emissions inside the plateau. Thus, we constructed a high‐resolution erodibility data set (ERODSDS) based on a reliable dust source distribution and intensity map. Based on the modified EROD map, the WRF‐Chem model was used to simulate dust emissions and direct radiative forcing on the TP in 2018. With the modified EROD map, WRF‐Chem can well simulate the temporal variation and spatial pattern of mineral dust on the plateau, which greatly improves the model's dust emissions simulation accuracy on the TP. Plain Language Summary: Due to certain limitations of the ERODDEF, the previous WRF‐Chem model was unable to accurately simulate dust emissions from the TP's interior. Thus, we constructed a more realistic ERODSDS and improved simulations of dust emissions and dust direct radiative forcing within the plateau. The west‐central part of the plateau is also an important source of dust emissions, and the amount of dust emitted within the plateau should not be neglected. Key Points: The WRF‐Chem model seriously underestimates local dust emissions on the Tibetan PlateauHigh‐precision erodibility data on the Tibetan Plateau is constructed to accurately describe the surface dust emission potentialThe temporal and spatial distribution of the local dust emission on the Tibetan Plateau was estimated [ABSTRACT FROM AUTHOR]

Turbulence intermittency driven by submeso motions limits the progress of turbulence theory. Field observations from the Horqin Atmospheric Boundary‐Layer and Environment Experimental Station, China were used to investigate turbulence intermittency. An automated algorithm to Separate and reconstruct Submeso and Turbulent motions (SST) was improved for more accurately extraction and quantitative characterization of submeso motions. The existing intermittency intensity indexes, the local intermittency strength of turbulence (LIST) and intermittency strength (IS), which are based on kinetic energy only, are revised by considering the potential energy of submeso and turbulent motions to quantify intermittency intensity more comprehensively. The analysis of eight cases revealed that turbulent intermittency events are characterized by quiescent (pulsation, material, and energy transportation are weak) and burst (pulsation, material, and energy transportation fluctuate violently) periods. The conversion of both the kinetic and potential energy of submeso to turbulent motion contributes to the transition from quiescent to burst periods. The transition always occurs after ∆TE$$ \Delta \mathrm{TE} $$ <0 (the total energy difference between the submeso motion and turbulence), followed by a significant increase in ∆TE$$ \Delta \mathrm{TE} $$. Atmospheric stability decreases during the transition from quiescent to burst periods in most cases. In a totally intermittent night, the burst periods take up most of the material and energy transport, and the amount transported is not smaller than that during a totally turbulent night. The weaker the intermittency at night, the greater the capacity of turbulent transport. A comparison of five types of turbulence intermittency intensity indexes highlights the consistency and advantages between LIST (IS) and indexes in the literature. Finally, we found that turbulent intermittency events tended to occur more easily in the atmospheric boundary layer (ABL) with small winds (U < 2 m s−1) or stable stratification (Rib > 1), although they can also occur in ABL with unstable stratification and in the non‐stationary state of the day–night transition. [ABSTRACT FROM AUTHOR]

Because of the unique geographical location of the Tibetan Plateau and its important role in global climate change, aerosol variability over the plateau has been of wide interest to the academic community. Most studies have focused on the influence of external aerosols; however, a few studies have been conducted on dust aerosols within the plateau. In this study, the plateau was divided into three regions, west, south, and north based on surface vegetation and climatic characteristics, and the Weather Research and Forecasting model with Chemistry was used to simulate the Tibetan Plateau from 2004 to 2006 to quantify the spatial and temporal variability of dust within the plateau with high resolution. The dust sources of the plateau are located in the northern part of the Qiangtang Plateau, the Yarlung Tsangpo River basin, the Namucuo and Lhasa regions, the Qaidam Basin, the source areas of the Yellow and Yangtze Rivers, and the Qinghai Lake and its surrounding areas. Owing to windy weather and arid soil conditions, the dust emissions of the three regions reached 11.00 × 107 (west), 3.30 × 107 (south) and 4.50 × 107 (north) μg·m-2, during winter, and remained at a low level from May to October. Although the annual variation in dust emissions was relatively consistent across the three regions, there were substantial differences in dust loading, with almost no dust present in the atmosphere in the south, a peak dust loading of 94.00 × 105 μg·m-2 in January in the west, and a bimodal structure in the north with peaks in April and October and a maximum value of 13.00 × 1010 μg·m-2, which was primarily influenced by the temperature 2 m above the ground. In summer 10 % of the dust that starts in the interior of the plateau can be transported to the upper troposphere (above 8 km). [ABSTRACT FROM AUTHOR]

While seagrass ecosystems are acknowledged for their role as blue carbon sinks, significant uncertainties remain regarding the sequestration of sediment inorganic carbon (SIC) and its broader implications for carbon cycling. These knowledge gaps hinder a comprehensive assessment of the contribution of seagrass ecosystems to the global carbon budget. To address this gap, the drivers and sources of SIC in nine seagrass ecosystems in the tropical Indo-Pacific were analyzed using partial least squares path modeling and carbon and oxygen isotopes binding Bayesian mixing models. We found that SIC content varies regionally, ranging from 0.03% to 10.18%, and is positively correlated with seagrass biomass, temperature, salinity, and coarse-grained sediment. SIC stocks ranged from 1.53 to 203.17 Mg C ha -1 , confirming the role of tropical Indo-Pacific seagrass ecosystems as a significant pool for SIC. SIC content and stock beneath seagrass ecosystems are generally higher than those in unvegetated areas due to the capacity to trap particles of the seagrass canopy. SIC beneath seagrass ecosystems affected by runoff is mainly from terrestrial inputs. Conversely, SIC under seagrass ecosystems regulated by seawater is primarily derived from local production and inputs from adjacent ecosystems and fish farming wastewater. This study provides a robust method to enhance the accuracy of blue carbon accounting in seagrass ecosystems by the inclusion of inorganic carbon burial., (© 2025 John Wiley & Sons Ltd.)

Seagrass ecosystems have received a great deal of attention for contributing to uptake of atmospheric CO 2 , and thereby helping to mitigate global climate change ('blue carbon'). Carbon budgets for seagrass ecosystems are developed by estimating air-sea CO 2 fluxes. Data for air-sea CO 2 flux for tropical seagrass ecosystems are lacking, which is problematic for constraining global seagrass carbon budgets. Here, we sought to address this important data gap for tropical seagrass ecosystems (dominated by Thalassia hemprichii and Enhalus acoroides) from the Hainan Island of South China Sea, while also testing what the main factors driving the variations of air-sea CO 2 fluxes are. We found that air-sea CO 2 fluxes exhibited a U-shape diurnal variability from 6 a.m. to 6 a.m. of the next day, with the highest and lowest air-sea CO 2 fluxes values at early morning and afternoon, respectively. Biological processes were the driving force for mediating diurnal variations of seawater pCO 2 . The pCO 2, sea in different seasons displayed a trend of increasing from spring, reaching maximum in summer and then a decreasing trend after summer, where water temperature, wind speed and seagrass growth mainly drove the variations. This resulted in net uptake of CO 2 in all seasons except during summer in our study seagrass ecosystems, with greater negative values found in autumn (-3.63 ± 0.76 mmol m -2 d -1 ) than those in winter (-2.84 ± 0.60 mmol m -2 d -1 ). While the nutrient loading induced seagrass biomass changes (especially the seagrass T. hemprichii), which mediated the air-sea CO 2 fluxes changes among different seagrass meadows. Net annual CO 2 uptake potential under low nutrient loading (-0.77 ± 0.16 mol m -2  yr -1 ) was 23-54 % greater than high nutrient loading seagrass meadows, with the average annual air-sea CO 2 flux of the three seagrass meadows as -0.64 ± 0.13 mol m -2  yr -1 . These results suggest that tropical seagrass meadows of Hainan Island are a significant CO 2 sink of atmospheric CO 2 , but this capacity can be diminished by nutrient loading. Scaling up, we estimate the annual atmospheric CO 2 uptake by seagrass meadows of Hainan Island (total area 55.28 km 2 ) was 1544 t of CO 2 yr -1 , equivalent to the annual emissions from the wholesale, retail, accommodation and catering industries of 164,000 tourists in Hainan Island. With carbon neutrality becoming an important part of global climate governance, this study provides timely information for capitalising on the ability of seagrasses to contribute to natural climate solutions., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)