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Ambient pressure has a certain inhibiting effect on underwater welding droplet transfer and the stability of welding process. Good droplet transfer of underwater welding plays an important role in improving repairing quality of underwater structures. As an additional droplet separating force, laser provides effective means in improving the welding quality. For quantitative analysis and comparison of laser enhanced effect on droplet transfer, a high-speed camera system to shoot the process of welding droplet transfer was designed and by adopting the frequency domain operation, a filter aiming at image processing of welding droplet was also designed to filter the ambient noise and diffraction fringe. Through edge detection algorithm, edges of droplet images were detected, and the size of droplet was computed accurately with welding wire as the reference. At last, droplets’ statues under different welding parameters were compared. The results show that the clear images of GMAW droplet separated from the noise background can be acquired, which makes the high-precision quantitative analysis of laser enhanced effect possible. All of the results lay a foundation for further test of laser enhanced hyperbaric underwater welding.

Organic nucleation is an important source of atmospheric aerosol number concentration, especially in pristine continental regions and during the preindustrial period. Here, we improve on previous simulations that overestimate boundary layer nucleation in the tropics and add changes to climate and land use to evaluate climate forcing. Our model includes both pure organic nucleation and heteromolecular nucleation of sulfuric acid and organics and reproduces the profile of aerosol number concentration measured in the Amazon. Organic nucleation decreases the sum of the total aerosol direct and indirect radiative forcing by 12.5%. The addition of climate and land use change decreases the direct radiative forcing (-0.38 W m-2) by 6.3% and the indirect radiative forcing (-1.68 W m-2) by 3.5% due to the size distribution and number concentration change of secondary organic aerosol and sulfate. Overall, the total radiative forcing associated with anthropogenic aerosols is decreased by 16%.

Biological particles, as a fraction of organic particles, potentially play a crucial role in ice nucleation processes. However, the contributions and relationships of biological components and organic matter (OM) to atmospheric ice nucleation remain largely unexplored. Here, total ice nucleating particles (INPs), heat‐resistant INPs, lysozyme‐resistant INPs, nanoscale INPs (<0.22 μm), and heat‐resistant nanoscale INPs in precipitation collected at the summit of Mt. Lu, China, were determined using droplet freezing assays coupled with corresponding pretreatments. Heat‐sensitive INPs and lysozyme‐sensitive INPs were considered as biological INPs and bacterial INPs, respectively. Microorganisms and OM molecules in precipitation were identified by high‐throughput sequencing technology and ultrahigh‐resolution mass spectrometry, respectively. Results revealed a predominant biological (heat‐sensitive) composition (78.8% and 93.2%) of total and nanoscale INPs at temperatures above −15°C. Specifically, bacterial (lysozyme‐sensitive) INPs accounted for 36.1% of the biological INPs at temperatures above −15°C. A notable correlation between sulfur‐containing organic compounds, mainly proteinaceous and lignin‐like substances, and INPs was uncovered, with a co‐occurrence network linking these compounds to Gram‐positive bacteria and Agaricomycetes. This study underscored the possible significance of sulfur‐containing organic compounds in the ice nucleation capacity of biological INPs, further shedding light on the ice nucleation mechanisms and potential sources of biological INPs. Plain Language Summary: Ice nucleating particles (INPs) are particles that facilitate the freezing of water at temperatures above the homogenous freezing point, impacting cloud formation and precipitation processes in the atmosphere. This study identified different types of INPs, microbes, and organic matter in precipitation sampled from Mt. Lu in southeastern China and investigated the connections among them. The findings suggested that a significant portion of INPs were of biological origin. Sulfur‐containing organic compounds likely played an important role in ice nucleation, which may originate from certain microbial taxa. This study helps us understand the role of microbes and organic molecules in ice formation, which has broader implications in areas such as preserving biological materials at low temperatures or facilitating artificial snow production. Key Points: Biological materials predominated among the ice nucleating particles (INPs) identified in precipitationSulfur‐containing organic compounds, associated with specific microbial taxa, likely acted as efficient INPs in precipitationThis study provides a preliminary understanding of the connections among INPs, organic matter, and microorganisms [ABSTRACT FROM AUTHOR]

Environmental context: Atmospheric particulate NH4+, primarily produced from the reaction of NH3 and acids, is an important component of PM2.5. In this study, nitrogen stable isotope analyses and an atmospheric chemistry model were used to estimate the contribution of major NH3 sources to particulate NH4+ in Tianjin, a megacity in North China Plain (NCP). Our research has implications for investigations of NH3 emission sources and relevant pollution control in Tianjin and NCP. Rationale: The North China Plain (NCP) has been identified as an NH3 emission hotspot. Source apportionment of NH3 is a prerequisite for controlling NH3 or NH4+ pollution. Nitrogen stable isotope (δ 15N) analysis is a promising method for NH3 source apportionment but its accuracy is still in question. Methodology: In this study, daytime and nighttime PM2.5 samples were collected from two sites in Tianjin, NCP, in autumn. Concentrations and δ 15N of particulate NH4+ were then measured. Nitrogen stable isotope analyses and isotope mixing model (MixSIAR), and an atmospheric chemistry model (WRF-CMAQ-ISAM) were used to estimate the sources of NH3 in Tianjin. Results: Results from the MixSIAR and WRF-CMAQ-ISAM models suggested that all the sources including livestock breeding, N-fertiliser application, fossil fuels, NH3 slip (especially from traffic), human waste and biomass burning (mostly from bioapplication) were non-negligible to NH3 and NH4+ in Tianjin. This high complexity is due to significant agricultural and industrial production and residential life in Tianjin and the surrounding regions. Our results indicate all NH3 sources need to be considered if we want to reduce NH4+ pollution in Tianjin in autumn. Environmental context. Atmospheric particulate NH4+, primarily produced from the reaction of NH3 and acids, is an important component of PM2.5. In this study, nitrogen stable isotope analyses and an atmospheric chemistry model were used to estimate the contribution of major NH3 sources to particulate NH4+ in Tianjin, a megacity in North China Plain (NCP). Our research has implications for investigations of NH3 emission sources and relevant pollution control in Tianjin and NCP. Photograph by Libin Wu. This article belongs to the collection Dedication to Roy Harrison. [ABSTRACT FROM AUTHOR]

Isoprene is a crucial non-methane biogenic volatile organic compound (BVOC) that exhibits the largest emissions globally. It is chemically reactive in the atmosphere and serves as the primary source of generating secondary organic aerosols (SOA) in terrestrial and remote marine regions. However, a comprehensive estimation of marine isoprene emissions is currently lacking. Here we built a module to present a 20-year (2001–2020) global hourly dataset for marine isoprene emissions, including phytoplankton-generated biological emissions (BIO emissions) and photochemistry-generated emissions in the sea surface microlayer (SML emissions) based on the latest advancements in biological, physical, and chemical processes, with high spatial resolutions. Our dataset suggests the annual global marine isoprene emissions amount to 1.097±0.009 Tg yr -1. Among these, the BIO emissions are 0.481±0.008 Tg yr -1 while SML emissions contribute 0.616±0.003 Tg yr -1. The ability of this module to estimate marine isoprene emissions was evaluated through comparison with a series of observations of marine isoprene concentrations and emission fluxes. The annual total isoprene emissions across the tropical ocean show a declining trend from 2001 to 2020. Most ocean regions exhibit a 1-year emission period, whereas a significant intraseasonal period is found in the tropical ocean. This dataset can be employed as input for the simulation of marine SOA formation in earth system models. This work provides the foundation for further studies into the impact of the air–sea system on marine SOA formation and its climate effect. The DOI link for the dataset is 10.11888/Atmos.tpdc.300521 (Cui and Zhu, 2023). [ABSTRACT FROM AUTHOR]

To investigate the prognostic value of N6-methyladenosine (m6A)-, 5-methylcytosine (m5C)-, and N1-methyladenosine (m1A)-related genes in cervical cancer (CESC) and predicting immunotherapy response. We downloaded cervical cancer mRNA expression profiles, clinical data, and m6A, m5C, m1A-related genes from public databases, and subjected them to serial bioinformatics analysis and clinical sample validation. Differential analysis revealed 106 methylation-related differential genes (MEDs), including 44 differentially downregulated and 62 upregulated genes. We then obtained methylation models containing 10 genes by univariate and multifactorial COX analysis. High risk genes with HR > 1 include IQGAP3, PTBP1, STAC3, CUX1, SLC2A1, and CA2, and low risk genes with HR < 1 include IGBP1, DUOX1, CHAF1A, and STAC3. We verified the accuracy of the model from inside TCGA and outside GSE39001 (AUC = 0.729). K-M analysis showed shorter survival times in the High-risk group, and Immunocytic infiltration analysis showed model genes closely associated with six immune cells. The high-risk group may benefit more effectively from immunosuppressive therapy, especially anti-CTLA-4 therapy (p <.05). We also screened nine drugs for potential treatment and verified the expression of three key genes SLC2A1, CUX1, and CA2 using immunohistochemistry and RT-qPCR experiments with clinical samples. We identified a prognostic model using m6A/m5C/m1A-related genes in cervical cancer, which can predict survival time and correlate with immune cell infiltration. Additionally, anti-CTLA-4 may be used as an immunotherapeutic agent for cervical cancer. Cervical cancer still has a high mortality rate, we aim to establish a strong prognostic index and new treatment goals for improving patient survival. The role of three types of RNA methylation modifications, m6A, m5C, and m1A, in cervical cancer, remains unknown. Therefore, it is essential to explore the potential molecular mechanisms of m6A, m5C, and m1A methylation regulation in cervical cancer. We also screened nine drugs for potential treatment and anti-CTLA-4 may be used as an immunotherapeutic agent for cervical cancer. We verified the expression of three key genes SLC2A1, CUX1, and CA2 [ABSTRACT FROM AUTHOR]