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Deep learning-based approaches for automatic depression recognition offer advantages of low cost and high efficiency. However, depression symptoms are challenging to detect and vary significantly between individuals. Traditional deep learning methods often struggle to capture and model these nuanced features effectively, leading to lower recognition accuracy. This paper introduces a novel multimodal depression recognition method, HYNMDR, which utilizes hypergraphs to represent the complex, high-order relationships among patients with depression. HYNMDR comprises two primary components: a temporal embedding module and a hypergraph classification module. The temporal embedding module employs a temporal convolutional network and a negative sampling loss function based on Euclidean distance to extract feature embeddings from unimodal and cross-modal long-time series data. To capture the unique ways in which depression may manifest in certain feature elements, the hypergraph classification module introduces a threshold segmentation-based hyperedge construction method. This method is the first attempt to apply hypergraph neural networks to multimodal depression recognition. Experimental evaluations on the DAIC-WOZ and E-DAIC datasets demonstrate that HYNMDR outperforms existing methods in automatic depression monitoring, achieving an F1 score of 91.1% and an accuracy of 94.0%. [ABSTRACT FROM AUTHOR]

Perfluorooctane sulfonate (PFOS) is a synthetic persistent organic compound that is widely used in industrial products. Studies have shown that PFOS can accumulate in environment and pose a threat to human health. As the kidney is the main excretory organ for PFOS, it is important to study PFOS damage to the kidney to investigate its toxicity. Human proximal tubular epithelial cells (HK-2) were treated with 200 μM PFOS or 1 μM Fer-1. Cell viability, the levels of MDA, GSH, intracellular iron ion, and GPX-4 were determined. The expression of KIM-1 and endoplasmic reticulum stress (ERS) related proteins were determined. The expression levels of KIM-1, a marker of renal tubular injury, and ERS-related proteins, GRP78, ATF6, IRE1, and PERK, were significantly increased in HK-2 cells exposed to PFOS. The levels of MDA and intracellular total iron ion also were significantly increased in HK-2 cells exposed to PFOS and the levels of GSH and GPX-4 were significantly decreased. PFOS can damage HK-2 cells through ferroptosis and endoplasmic reticulum stress, which provides a theoretical foundation for exploring the toxicity of PFOS to the kidney. [ABSTRACT FROM AUTHOR]

The popularisation of mobile information technology has provided access to the living habits and activity trajectories of residents and enabled the accurate measurement of the impact of urban haze disasters on residents' lives, supporting urban haze risk response. Using the main urban area of Gaoyou City as a case study, this study identifies the spatial range and trajectory characteristics of the daily activities of residents in a haze disaster environment, based on air pollution monitoring and resident travel positioning data. We constructed an evaluation index system to measure the corresponding relationship between residential activities and haze disasters. The results indicate that the interference with residential activities and the adaptability of built environments are key indicators for evaluating urban resilience in haze environments, with weights of 0.57 and 0.43, and correlation indices of 0.67 and 0.81, respectively. The interference with residential activities and the adaptability of built environments exhibit spatial characteristics of cold and hot 'multi-core' agglomeration and 'strip' agglomeration, respectively. Specific indicators show that the residential activity exposure index is significantly influenced by the built environment factor index, with the vegetation coverage index showing a significant positive correlation (0.837) and the public transportation facility accessibility index showing a significant negative correlation (−1.242). Planning should focus on improving the adaptability of the built environment or reducing the interference with residential activities and enhancing the matching degree of the two at the spatial facility level. [ABSTRACT FROM AUTHOR]

The spatiotemporal variation of fog reflects the complex interactions among fog, boundary layer thermodynamics and synoptic systems. Previous studies revealed that fog can present a fast spatial propagation feature and attribute it to the boundary layer low-level jet (BLLJ), but the effect of the BLLJ on fog propagation is not quantitatively understood. Here we analyze a large-scale fog event in Jiangsu, China, from 20 to 21 January 2020. Satellite retrievals show that fog propagates from the southeast coastal area to the northwest inland area with a speed of 9.6 m s -1 , which is 3 times larger than the ground wind speeds. The ground meteorologies are insufficient to explain the fast fog propagation, which is further investigated by Weather Research and Forecasting model (WRF) simulations. The fast fog propagation could be attributed to the BLLJ occurring between 50 and 500 m, because the wind speeds (10 m s -1) and directions (southeast) of the BLLJ core are consistent with fog propagation. Through sensitive experiments and process analysis, three possible mechanisms of the BLLJ are revealed: (1) the abundant oceanic moisture is transported inland, increasing the humidity of the boundary layer and promoting condensation; (2) the oceanic warm air is transported inland, enhancing the inversion layer and favoring moisture accumulation; and (3) the moisture advection probably promotes low-stratus formation, and later it subsides to become ground fog by turbulent mixing of fog droplets. The fog propagation speed would decrease notably by 6.4 m s -1 (66 %) in the model if the BLLJ-related moisture and warm advections were turned off. [ABSTRACT FROM AUTHOR]

With the improvement in residents' living standards, non-commuting has gradually become an important daily transportation behaviour for residents. The intensity of non-commuting flow can reflect the level of urban functional services and external attractiveness and can intuitively characterise the interconnection pattern and relationship among various cities within the metropolitan area. Related research is also a key topic in the fields of urban planning and transportation geography from a humanistic perspective. Taking the Shanghai Metropolitan Area as an example, this study explored the characteristics of the non-commuting flow of residents in the region and between cities and its nonlinear influencing factors with the help of the mobile phone signalling data and the gradient lifting decision tree model. Three conclusions were identified: first, non-commuting flow within each city in the metropolitan area was concentrated in the central urban area, while non-commuting flow between cities was concentrated in the central urban area of the urban border and strong core cities. Second, the built environment had a nonlinear impact on residents' non-commuting flow. Different types of large-scale service facilities had different impact mechanisms on non-commuting flow, and public service facilities and transportation infrastructure jointly affected residents' non-commuting flow. Third, transportation facilities had a more significant impact on the non-commuting flow between cities. Large tourism, cultural, and medical service facilities had a more significant impact on non-commuting flow within cities, with upper or lower thresholds according to the type of facility. The planning strategy needs to conduct targeted planning, regulation, and facility configuration based on the area's actual needs. In addition, this study identified the characteristics of non-commuter flow differentiation in street towns and the nonlinear impact of the built environment. [ABSTRACT FROM AUTHOR]

Aerosol–cloud interaction (ACI) in fog and planetary boundary layer (PBL) conditions plays critical roles in the fog life cycle. However, it is not clear how ACI in the first fog (Fog1) affects the PBL and subsequently affects ACI in the second fog (Fog2), which is important information for understanding the interaction between ACI and the PBL, as well as their effects on fog properties. To fill this knowledge gap, we simulate two successive radiation fog events in the Yangtze River Delta, China, using the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem). Our simulations indicate that the PBL conditions conducive to Fog2 formation are affected by ACI with high aerosol loading in Fog1; subsequently, the PBL promotes ACI in Fog2, resulting in a higher liquid water content, higher droplet number concentration, smaller droplet size, larger fog optical depth, wider fog distribution, and longer fog lifetime in Fog2 than in Fog1. This phenomenon is related to the following physical factors. The first factor involves meteorological conditions conducive to Fog2 formation, including low temperature, high humidity, and high stability. The second factor is the feedbacks between microphysics and radiative cooling. A higher fog droplet number concentration increases the liquid water path and fog optical depth, thereby enhancing long-wave radiative cooling and condensation near the fog top. The third factor is the feedbacks between macrophysics, radiation, and turbulence. A higher fog top presents stronger long-wave radiative cooling near the fog top than near the fog base, which weakens temperature inversion and strengthens turbulence, ultimately increasing the fog-top height and fog area. In summary, under polluted conditions, ACI postpones the dissipation of Fog1 owing to these two feedbacks and generates PBL meteorological conditions that are more conducive to the formation of Fog2 than those prior to Fog1. These conditions promote the earlier formation of Fog2, further enhancing the two feedbacks and strengthening the ACI in Fog2. Our findings are critical for studying the interaction between aerosols, fog, and the PBL; moreover, they shed new light on ACI. [ABSTRACT FROM AUTHOR]

There are few existing studies from a spatial perspective that explore the mechanism of the living environment, relocated direction and relocated distance on the elderly's physical and mental health. Based on the 2019 household survey questionnaire data, this study utilizes a binomial logistic regression model and residents' in-depth interviews to study relocated behavior in Nanjing. We analyzed the spatial–temporal characteristics of relocated behaviors, the accumulation effect at different stages and the influence of relocated intention on physical and mental health among the elderly. The findings are as follows: (1) The mode of relocation among the elderly includes long-term cumulative effects and short-term effects. Frequent relocation has a cumulative negative impact on the physical and mental health of the elderly. (2) The elderly relocated in the short-term had a great negative impact on their mental health but had no significant impact on their physical health. (3) In the last relocation, active relocation had a significantly positive impact on physical health. The "centrifugal relocation" from the main urban area to the surrounding new cities has a significant positive impact on mental health. Moreover, long-distance relocations adversely affected mental health. [ABSTRACT FROM AUTHOR]

Weak turbulence often occurs during heavy pollution events in eastern China. However, existing mesoscale models cannot accurately simulate turbulent diffusion under weakened turbulence, particularly under the nocturnal stable boundary layer (SBL), often leading to significant turbulent diffusivity underestimation and surface aerosol simulation overestimation. In this study, based on the Weather Research and Forecasting model coupled with the Chemistry model (WRF-Chem 3.9.1), a new parameterization of minimum turbulent diffusivity (Kzmin) is tested and applied in PM2.5 simulations in eastern China under SBL conditions. Sensitivity experiments show that there are different value ranges of available Kzmin over the northern (0.8 to 1.3 m2·s-1) and southern (1.0 to 1.5 m2·s-1) regions of East China. The geographically related Kzmin could be parameterized by means of two factors: sensible heat flux (H) and latent heat flux (LE), which also exhibited a regional difference related to the climate and underlying surface. The revised Kzmin scheme obviously enhanced the turbulent diffusion (north: 0.88 m2·s-1, south: 1.17 m2·s-1 on average) under the SBL, simultaneously improving the PM2.5 simulations, with the PM2.5 relative bias decreasing from 43.0 % to 15.6 % on the surface. The improvement in the mean bias of the surface simulation was more noticeable in the north (54.01 to 3.79 ug·m-3) than in the south (37.05 to 17.99 ug·m-3). It also increased the PM2.5 concentration in the upper SBL. Furthermore, we discussed the physical relationship between Kzmin and two factors. Kzmin was inversely correlated with sensible heat flux (negative) and latent heat flux (positive) in the SBL. Process analysis showed that vertical mixing is the key process to improve PM2.5 simulations on the surface in the revised scheme. The increase in the PM2.5 concentration in the upper SBL was attributed to vertical mixing, advection, and aerosol chemistry. This study highlights the importance of improving turbulent diffusion in current mesoscale models under the SBL and has great significance for aerosol simulation research under heavy air pollution events. [ABSTRACT FROM AUTHOR]

Ultraviolet-B (UVB) radiation is an important factor in causing skin damage. The study is to explore whether 1,25-Dihydroxvitamin D3(1,25(OH)2D3) will attenuate the damage of human immortalised keratinocytes (HaCaT) cells caused by UVB and relevant underlying mechanisms. CCK-8 was employed to determine the UVB irradiation intensity and 1,25(OH)2D3 concentration. Western blot was used to detect the expression of NF-κB, Caspase9, Caspase3, Bax, Bcl2, FADD, CytC, Beclin-1; Flowcytometry was applied to measure the production of ROS. The concentration of 1,25(OH)2D3 used in the study was 100 nM and the UVB irradiation intensity was 20 mJ/cm2. Compared with the HaCaT cells irradiated with UVB, the HaCaT cells that were pre-treated with 1,25(OH)2D3 had lower production of ROS, lower expression of NF-κB, Caspase9, Caspase3, Bax, FADD, CytC and Beclin-1(P < 0.05). 1,25(OH)2D3 could inhibit the development of oxidative stress and apoptosis in HaCaTs triggered by UVB. This inhibition might be achieved through the suppression of mitochondria-modulated apoptosis and autophagy. Vitamin D may be a potential UVB protective component. [ABSTRACT FROM AUTHOR]

Tropospheric ozone, an important secondary pollutant, is greatly impacted by aerosols within boundary layer (BL). Previous studies have mainly attributed ozone variation to either aerosol–BL or aerosol–photolysis interactions at the near-surface level. In this study, we analyze the sensitivities of ozone response to aerosol mixing states (e.g., mixing behavior hypothesis of scattering and absorbing components) in the vertical direction and address the effects of aerosol–BL and aerosol–photolysis interactions on ozone profiles in autumn by Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) simulations. The aerosol internal mixing state experiment reasonably reproduces the vertical distribution and time variation in meteorological elements and ozone. Sensitivity experiments show that aerosols lead to turbulent suppression, precursor accumulation, lower-level photolysis reduction, and upper-level photolysis enhancement. Consequently, ozone basically decreases within entire the BL during daytime (08:00–17:00 LT), and the decrease is the least in the external mixing state (2.0 %) when compared with internal (10.5 %) and core shell mixing states (8.6 %). The photolysis enhancement is the most significant in the external mixing state due to its strong scattering ability. By process analysis, lower-level ozone chemical loss is enhanced due to photolysis reduction and NO x accumulation under a volatile organic compound (VOC)-limited regime. Upper-level ozone chemical production is accelerated due to a higher photolysis rate resulting from aerosol backscattering. Therefore, the increased ozone entrainment from BL aloft to the surface induced by the boosted ozone vertical gradient outweighs the decreased ozone entrainment induced by turbulent suppression after 11:00 LT. Additional simulations support the finding that the aerosol effect on precursors, photolysis, and ozone is consistent under different underlying surface and pollution conditions. [ABSTRACT FROM AUTHOR]

Understanding cloud droplet relative dispersion is critical for mitigating the confounding effect of aerosol‐cloud interactions in the simulation of the global climatic patterns. Diverse dispersion effects, meaning that the correlation between relative dispersion (ε) and fog droplet number concentration (Nf) changes from positive to negative as Nf increases at a fixed liquid water content (LWC) condition, were found in the urban fog observed during the winters of 2017 and 2018 in Nanjing, China. The dominant microphysical processes driving the diverse dispersion effects were found to be activation, condensation, deactivation, evaporation, and sedimentation. The critical first bin (diameter range of 2–4 μm) strength and volume‐mean diameter (Dv) for classifying the diverse dispersion effects are 0.3–0.4 and 10–12 μm, respectively. The mean dispersion offset (DO) was −27.6% for weakening the Twomey effect and 27.5% for enhancing it. Assuming the Gamma distribution for the fog droplet number size distribution, the mean dispersion effect was significantly underestimated at DO < 0. Based on the measured nonmonotonic relationship between ε and Dv, we establish ε parameterization using a Nelder function, which can be applied to the diverse dispersion effects. The mean deviation for diagnosing DO was less than 10% for DO > 0 and less than 50% for DO < 0. These results could shed new light on understanding the diverse dispersion effects, which cloud help reduce the uncertainties in the simulation of aerosol‐cloud interactions. Plain Language Summary: Cloud droplet relative dispersion, defined as the standard deviation over the mean droplet size, is of central importance in determining and understanding aerosol indirect effects. Field fog experiments are an effective way to study the dispersion effect; this is due to the ease of accessing fog, since it is essentially a grounded cloud. Diverse dispersion effects were found in urban fog observed in eastern China. The dominant microphysical processes driving the diverse dispersion effects were found to be activation, condensation, deactivation, evaporation, and sedimentation. Whether the small droplet segment of the fog maintains its peak in droplet number size distribution is a key factor in determining the various dispersion effects. A nonmonotonic parameterization of the relative dispersion was established to diagnose the dispersion effects. Our results could shed new light on the dispersion effects, in turn, improving simulation of aerosol‐cloud interactions. Key Points: Diverse dispersion effects were found in urban fogPossible microphysical mechanisms were proposed for explaining the elucidated dispersion effectsA nonmonotonic parameterization of relative dispersion was established to diagnose the dispersion effects [ABSTRACT FROM AUTHOR]

Studies on the vitality of urban residents' daily commuting and air pollution are scarce. Based on the cell phone mobile signaling data, urban air quality observation data, and urban transportation infrastructure environment data of Nanjing in 2019, and through the panel regression model and the standard deviation ellipse analysis (SDE) to measure the impact of air pollution on residents' daily traffic vitality, we construct the survey panel matrix data system with streets as spatial units. Through SDE and panel regression model analysis, we measured the restraining effect of air pollution on the traffic vitality. The scope of the traffic vitality area SDE was found to shrink as the air quality index (AQI) increases. The study found three main characteristics: (1) Under different transportation models and different location conditions, there are obvious differences in traffic vitality. The entire city presents a trend of "northeast-southwest" axial expansion in the spatial pattern of the traffic vitality. Compared with the urban core area, the traffic vitality of residents in the north-south areas of Nanjing's periphery has declined significantly. (2) The inhibitory effect of air pollution on public traffic vitality and self-driving traffic vitality are differences. Approximately one-tenth of traffic activities may be inhibited by air pollution. The weakening of traffic vitality greatly reduces the city's ability to attract and gather people, materials, and resources. (3) The inhibitory effect of air pollution on traffic vitality is heterogeneous under different transportation infrastructure environments. The higher the public transportation station density and public transportation frequency of the street, the more obvious the suppression effect of air pollution. The higher the parking density, station accessibility, road intersections density, and transportation facility diversity, the lower the suppression effect of air pollution. This study elucidates the relationship among air pollution, the transportation infrastructure environment, and the traffic vitality, and provides significant guidelines for optimizing the organization of elements in the transportation infrastructure environment, thereby mitigating the inhibitory effect of air pollution on traffic vitality. [ABSTRACT FROM AUTHOR]

(1) Background: Perfluorooctane sulfonate (PFOS) is a persistent organic pollutant, and it is receiving increasing attention regarding its human health risks due to its extensive use. Endothelial dysfunction is a mark of cardiovascular disease, but the basic mechanism of PFOS-induced endothelial dysfunction is still not fully understood. Ferroptosis is a newly defined regulatory cell death driven by cellular metabolism and iron-dependent lipid peroxidation. Although ferroptosis has been shown to be involved in the pathogenesis of cardiovascular diseases, the involvement of ferroptosis in the pathogenesis of endothelial dysfunction caused by PFOS remains unclear. (2) Purpose: To explore the role of ferroptosis in the dysfunction of endothelial cells and underlying mechanisms. (3) Methods: Human umbilical vein endothelial cells (HUVECs) were exposed to PFOS or PFOS and Fer-1. The viability, morphology change under electronic microscope, lipid-reactive oxygen species (lipid-ROS), and production of nitric oxide (NO) were determined. The expression of glutathione peroxidase 4(GPX4), ferritin heavy chain protein 1 (FTH1), heme oxygenase 1 (HO-1) and Acyl-CoA synthetase long-chain family member 4 (ACSL4) were analyzed via Western blot analysis. (4) Results: PFOS was shown to cause a decrease in viability and morphological changes of mitochondria, and well as an increase in lipid droplets. The expression of GPX4, FTH1 and HO-1 was decreased, and that of ACSL4 was increased after exposure to PFOS. In addition to the above-mentioned ferroptosis-related manifestations, there was also a reduction in NO content. (5) Conclusions: PFOS induces ferroptosis by regulating the GPX4 and ACSL4 pathways, which leads to HUVEC dysfunction. [ABSTRACT FROM AUTHOR]

Perfluorooctane sulfonate (PFOS) is a typical persistent organic pollutant and environmental endocrine disruptor that has been shown to be associated with the development of many diseases; it poses a considerable threat to the ecological environment and to human health. PFOS is known to cause damage to renal cells; however, studies of PFOS-induced ferroptosis in cells have not been reported. We used the CCK-8 method to detect cell viability, flow cytometry and immunofluorescence methods to detect ROS levels and Western blot to detect ferroptosis, endoplasmic reticulum stress, antioxidant and apoptosis-related proteins. In our study, we found that PFOS could induce the onset of ferroptosis in HK-2 cells with decreased GPx4 expression and elevated ACSL4 and FTH1 expression, which are hallmarks for the development of ferroptosis. In addition, PFOS-induced ferroptosis in HK-2 cells could be reversed by Fer-1. We also found that endoplasmic reticulum stress and its mediated apoptotic mechanism and P53-mediated antioxidant mechanism are involved in the toxic damage of cells by PFOS. In this paper, we demonstrated for the first time that PFOS can induce ferroptosis in HK-2 cells. In addition, we preliminarily explored other mechanisms of cytotoxic damage by PFOS, which provides a new idea to study the toxicity of PFOS as well as the damage to the kidney and its mechanism. [ABSTRACT FROM AUTHOR]

Perfluorooctane sulfonate (PFOS) is a persistent, widely present organic pollutant. PFOS can enter the human body through drinking water, ingestion of food, contact with utensils containing PFOS, and occupational exposure to PFOS, and can have adverse effects on human health. Increasing research shows that the liver is the major target of PFOS, and that PFOS can damage liver tissue and disrupt its function; however, the exact mechanisms remain unclear. In this study, we reviewed the adverse effects of PFOS on liver tissue and cells, as well as on liver function, to provide a reference for subsequent studies related to the toxicity of PFOS and liver injury caused by PFOS. [ABSTRACT FROM AUTHOR]

Vasoactive intestinal peptide (VIP) plays an important role in the neuro-endocrine-immune system. Mast cells (MCs) are important immune effector cells. This study was conducted to investigate the protective effect of L. casei ATCC 393 on Enterotoxigenic Escherichia coli (ETEC) K88-induced intestinal mucosal immune barrier injury and its association with VIP/MC signaling by in vitro experiments in cultures of porcine mucosal mast cells (PMMCs) and in vivo experiments using VIP receptor antagonist (aVIP) drug. The results showed that compared with the ETEC K88 and lipopolysaccharides (LPS)-induced model groups, VIP pretreatment significantly inhibited the activation of MCs and the release of β-hexosaminidase (β-hex), histamine and tryptase. Pretreatment with aVIP abolished the protective effect of L. casei ATCC 393 on ETEC K88-induced intestinal mucosal immune barrier dysfunction in C57BL/6 mice. Also, with the blocking of VIP signal transduction, the ETEC K88 infection increased serum inflammatory cytokines, and the numbers of degranulated MCs in ileum, which were decreased by administration of L. casei ATCC 393. In addition, VIP mediated the regulatory effect of L. casei ATCC 393 on intestinal microbiota in mice. These findings suggested that VIP may mediate the protective effect of L.casei ATCC 393 on intestinal mucosal immune barrier dysfunction via MCs. [ABSTRACT FROM AUTHOR]

Observations suggest that the vertical distributions of air pollutants, such as black carbon (BC), present as various types depending on the emission sources and meteorological diffusion conditions. However, the formation process and source appointment of some special BC profiles are not fully understood. In this paper, by using the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) with a BC-tagging technique, we investigate the formation mechanism and regional sources of a BC peak in the free troposphere observed by an aircraft flight in Beijing (BJ) on 5 May 2018. The results show that the contribution rate of the Beijing–Tianjin–Hebei (BTH) region to the surface BC of BJ exceeded 80 % in this case. Local sources dominated BC in BJ from the surface to approximately 700 m (78.5 %), while the BC peak in the free troposphere (∼4000 m) was almost entirely imported from external sources (99.8 %). Combining BC tracking and process analysis, we find that horizontal advection (HADV) and vertical advection (VADV) processes played an important role in the convergent and upward movement and the transport of BC. The BC originating from the surface in central provinces, including Shanxi (SX), Henan (HN), and Hebei (HB), had been uplifted through a cyclone system 16 h previously, was transported to a height of approximately 3000 m above BJ, and was then lifted by the VADV process to approximately 4000 m. At the surface, BJ and its surroundings were under the control of a weak pressure gradient, leading to the accumulation of BC within the boundary layer. Our results indicate that cyclone systems can quickly lift air pollutants, such as BC, up to the free troposphere, as well as extend their lifetimes and further affect the regional atmospheric environment and climate. [ABSTRACT FROM AUTHOR]

A new approach is developed for estimating entrainment and detrainment rates in cumulus clouds based on aircraft observations. Equations relating entrainment and detrainment rates to gross entrainment and detrainment are derived. This approach is applied to the Holistic Interactions of Shallow Clouds, Aerosols, and Land‐Ecosystems field campaign, supported by the U.S. Department of Energy's Atmospheric Radiation Measurement program. The results show that both entrainment and detrainment rates decrease with increasing height. Sensitivity tests with different detrained air assumptions yield similar results. The entrainment and detrainment rates can reproduce the cloud thermodynamic variables. Partial correlation analysis indicates that entrainment rate is positively correlated with environmental relative humidity (RH), and detrainment rate is negatively correlated with environmental RH and positively correlated with entrainment rate. This new approach can be applied to other cloud observations to obtain a data set of entrainment and detrainment rates in cumulus clouds. Plain Language Summary: Entrainment and detrainment rates are key properties in the simulation of cumulus clouds. Previous studies have diagnosed entrainment and detrainment rates in simulation experiments. However, there is no published approach for simultaneous estimation of entrainment and detrainment rates using aircraft observations. A new approach is presented to fill this gap. This approach is applied to aircraft observations of shallow cumulus clouds. Both entrainment and detrainment rates decrease with increasing height. The results are verified by reproducing the variables in the cloud. Using the new approach to obtain a data set of entrainment and detrainment rates could help improve shallow convection parameterizations in models. Key Points: A new approach for simultaneously estimating entrainment and detrainment rates in cumulus clouds is presentedEstimated entrainment and detrainment rates can reproduce cloud thermodynamic variablesEffects of environmental relative humidity on entrainment rate and detrainment rate are consistent with buoyancy sorting [ABSTRACT FROM AUTHOR]

Long‐range transport of PM2.5 from the North China Plain (NCP) by cold frontal passage is considered to be an important haze formation mechanism in the Yangtze River Delta (YRD). However, detailed 3D distributions of PM2.5 and meteorological fields during the front moving through are not fully understood. Herein, in situ observations showed that most haze events in autumn and winter in the YRD were associated with cold frontal passages. A typical cold front episode on November 2–3, 2017, was investigated with unmanned aerial vehicle sounding and model simulations, which both revealed that PM2.5 in the upper air (∼1.0 km) reached the YRD earlier than that moving at the ground level. When the cold front reached the NCP, air pollutants ahead of the front was lifted from the ground level to the upper air. Subsequently, increased PM2.5 concentrations and higher wind speed in the upper air resulted in stronger PM2.5 outflow from the NCP to YRD compared to that at ground level. The maximum PM2.5 mass contribution from the NCP to YRD was 15.6 μg m−3 (accounted for 31.5% of the total PM2.5 in the YRD), which appeared at ∼1.0 km altitude. Compared to the noncold front period, the PM2.5 mass transported from the NCP was 10–15 times higher during the cold front episode. Results indicate that the combination of multisite sounding and elaborate simulation can effectively explain the impact of synoptic processes on the transport, distribution, and evolution of air pollution and provide precise pollution control directives. Key Points: Most haze events in autumn and winter in the Yangtze River Delta were associated with cold frontal passagesBoth unmanned aerial vehicle sounding and model simulation revealed a stronger and faster upper‐level transport of PM2.5 than at ground levelThe PM2.5 mass transported from the North China Plain was 10–15 times higher during a cold front episode [ABSTRACT FROM AUTHOR]

The aerosol–cloud interaction (ACI) and aerosol–radiation interaction (ARI) have notable influences on clouds, but their effects on fog are rarely analyzed before. Previous studies indicate that fog frequency in East China has been decreasing, and we further reveal that fog duration increases during 1960–2010. We hypothesize that this trend is related to the increase of aerosol pollution and perform WRF‐Chem simulations to study the ARI and ACI effects. Results show that ACI significantly advances fog formation, delays fog dissipation, and increases fog duration by about 1 h in a case study, while ARI has negligible effect. The more but smaller fog droplets produced in polluted conditions significantly inhibit droplet sedimentation and reduce solar radiation, therefore provide favorable conditions for the duration of fog. Under extremely polluted conditions, ACI effect also far overweighs ARI effect. To shorten the duration of dense fog, our findings suggest the necessity for mitigating emissions. Plain Language Summary: Aerosols, the suspensions of solid or liquid particles in the air, affect clouds through aerosol–cloud interaction (ACI) and aerosol–radiation interaction (ARI). The ARI refers to that aerosols affect the meteorological conditions in clouds by scattering and absorbing radiation. The ACI refers to that clouds form on aerosols if aerosols absorb sufficient water vapor. Fog is a kind of near‐surface cloud. The ARI and ACI could have both notable influences on fog, but their effects are rarely analyzed before. Previous studies indicate that fog frequency in East China has been decreasing, and in this study we further reveal that fog duration increases during 1960–2010. We hypothesize that this trend is related to the increase of aerosol pollution and perform numerical simulations to study the ARI and ACI effects. Results show that ACI significantly advances fog formation, delays fog dissipation, and increases fog duration by about 1 h in the case study, while ARI has negligible effect. The ACI can significantly inhibit fog droplet sedimentation and reduce solar radiation, therefore provide favorable conditions for the duration of fog. Our findings suggest that reducing emissions could shorten fog duration and mitigate the hazards of fog. Key Points: Fog frequency in East China is decreasing, and fog duration is increasingThe increase in fog duration is mainly caused by aerosolsAerosol–cloud interaction plays a more important role in increasing fog duration than aerosol–radiation interaction [ABSTRACT FROM AUTHOR]

The apparent turbulent entrainment‐mixing mechanism between clouds and surrounding air is scale dependent; however, such scale dependence has been rarely studied, hindering development of scale‐aware entrainment‐mixing parameterizations. Here we extend our previous study on cumulus clouds to investigate scale dependence of entrainment‐mixing processes in stratocumulus clouds during Aerosol and Cloud Experiments in Eastern North Atlantic and Routine AAF (Atmospheric Radiation Measurement (ARM) Aerial Facility) Clouds with Low Optical Water Depths (CLOWD) Optical Radiative Observations (RACORO). In contrast to previous studies, two opposite scale dependencies are found: Entrainment mixing can become more homogeneous or more inhomogeneous with increasing averaging scales, which is quantified by the difference between homogeneous mixing degree at the 100 and 10 m resolutions. A new heuristic model and two new quantities are introduced. The observations and model show that microphysical properties near and far away from droplet‐free air and relative humidity of entrained air determine both the sign and strength of scale dependence, while droplet‐free air fraction only affects the strength. The results shed new light on developing scale‐aware parameterizations of entrainment‐mixing mechanisms. Plain Language Summary: Turbulent entrainment mixing between clouds and surrounding air significantly affects cloud microphysical properties over a wide range of scales, indicating that the apparent entrainment‐mixing mechanism is scale dependent. Previous studies have shown that entrainment‐mixing mechanisms tend to be more inhomogeneous when the sampling rate is lower. Surprisingly, the present study shows two opposite behaviors of scale dependence: The mechanisms can become more homogeneous or more inhomogeneous. To understand the physical mechanisms responsible for the scale dependence, a new heuristic model is established. Cloud microphysics and relative humidity of the entrained air determine both the sign and strength of scale dependence, while droplet‐free air fraction only determines the strength. Two new quantities combining all the factors are defined, and they can better quantify the effects of the factors on scale dependence than each individual factor. This study finds a new phenomenon of scale dependence and improves our physical understanding of entrainment mixing. Key Points: Entrainment‐mixing mechanisms can become more homogeneous or inhomogeneous with increasing averaging scalesScale dependence sign and strength are related to microphysical properties, entrained air relative humidity, and droplet‐free air fractionA new heuristic model and two new dimensionless parameters are introduced to quantify the scale dependence [ABSTRACT FROM AUTHOR]

The remarkable development of China has resulted in rapid urbanization (urban heat island and dry island) and severe air pollution (aerosol pollution). Previous studies demonstrate that these two factors have either suppressing or promoting effects on fog, but what are the extents of their individual and combined effects? In this study, a dense radiation fog event in eastern China in January 2017 was reproduced by the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem), and the individual and combined effects of urbanization and aerosols on fog (indicated by liquid water content – LWC) are quantitatively revealed. Results show that urbanization inhibits low-level fog, delays its formation and advances its dissipation due to higher temperatures and lower saturations. In contrast, upper-level fog could be enhanced because of the updraught-induced vapour convergence. Aerosols promote fog by increasing LWC, increasing droplet concentration and decreasing droplet effective radius. Further experiments show that the current pollution level in China could still be below the critical aerosol concentration that suppresses fog. Urbanization influences fog to a larger extent than aerosols do. When urbanization and aerosol pollution are combined, the much weaker aerosol-promoting effect is counteracted by the stronger urbanization-suppressing effect on fog. Budget analysis of LWC reveals that urban development (urbanization and aerosols) alters the LWC profile and fog structure mainly by modulating condensation–evaporation process. Our results infer that urban fog will be further reduced if urbanization keeps developing and air quality keeps deteriorating in the future. [ABSTRACT FROM AUTHOR]

Lightning serves as the dominant source of nitrogen oxides (NOx=NO+NO2) in the upper troposphere (UT), with a strong impact on ozone chemistry and the hydroxyl radical production. However, the production efficiency (PE) of lightning nitrogen oxides (L NOx) is still quite uncertain (32–1100 mol NO per flash). Satellite measurements are a powerful tool to estimate L NOx directly compared to conventional platforms. To apply satellite data in both clean and polluted regions, a new algorithm for calculating L NOx has been developed that uses the Berkeley High-Resolution (BEHR) v3.0B NO2 retrieval algorithm and the Weather Research and Forecasting model coupled with chemistry (WRF-Chem). L NOx PE over the continental US is estimated using the NO2 product of the Ozone Monitoring Instrument (OMI) data and the Earth Networks Total Lightning Network (ENTLN) data. Focusing on the summer season during 2014, we find that the lightning NO2 (L NO2) PE is 32±15 mol NO2 per flash and 6±3 mol NO2 per stroke while L NOx PE is 90±50 mol NOx per flash and 17±10 mol NOx per stroke. Results reveal that our method reduces the sensitivity to the background NO2 and includes much of the below-cloud L NO2. As the L NOx parameterization varies in studies, the sensitivity of our calculations to the setting of the amount of lightning NO (LNO) is evaluated. Careful consideration of the ratio of L NO2 to NO2 is also needed, given its large influence on the estimation of L NO2 PE. [ABSTRACT FROM AUTHOR]

Lactococcus lactis (L. lactis) NZ9000, which has been genetically modified, is the most commonly used host strain for nisin regulated gene expression. Selenium (Se) is an essential trace element in the diet of humans and animals important for the maintenance of health and growth. Biosynthesized Se nanoparticles (SeNPs) that use microorganisms as a vehicle are uniquely advantages in terms of low costs, low toxicity and high bioavailability. This study was aimed at preparing novel functionalized SeNPs by L. lactis NZ9000 through eco-friendly and economic biotechnology methods. Moreover, its physicochemical characteristics, antioxidant and anti-inflammatory activities were investigated. L. lactis NZ9000 synthesized elemental red SeNPs when co-cultivated with sodium selenite under anaerobic conditions. Biosynthesized SeNPs by L. lactis NZ9000 were mainly capped with polysaccharides and significantly alleviated the increase of malondialdehyde (MDA) concentration, the decrease of glutathione peroxidase (GPx) and total superoxide dismutase (T-SOD) activity in porcine intestinal epithelial cells (IPEC-J2) challenged by hydrogen peroxide (H2O2). SeNPs also prevented the H2O2-caused reduction of transepithelial electrical resistance (TEER) and the increase of FITC-Dextran fluxes across IPEC-J2. Moreover, SeNPs attenuated the increase of reactive oxygen species (ROS), the reduction of adenosine triphosphate (ATP) and the mitochondrial membrane potential (MMP) and maintained intestinal epithelial permeability in IPEC-J2 cells exposed to H2O2. In addition, SeNPs pretreatment alleviated the cytotoxicity of Enterotoxigenic Escherichia coli (ETEC) K88 on IPEC-J2 cells and maintained the intestinal epithelial barrier integrity by up-regulating the expression of Occludin and Claudin-1 and modulating inflammatory cytokines. Biosynthesized SeNPs by L. lactis NZ9000 are a promising selenium supplement with antioxidant and anti-inflammatory activities. [ABSTRACT FROM AUTHOR]

During the past five decades, China has witnessed frequent fog and haze events. Previous studies have revealed that in polluted regions of East China, such as the Beijing‐Tianjin‐Hebei (BTH) region, the Yangtze River Delta (YRD) region, and the Pearl River Delta (PRD) region, fog frequencies are impacted not only by climate change but also by fast urbanization and increasing air pollution. In this study, we find that haze days increased markedly in the three regions. However, fog days showed an initially increasing and then decreasing trend, with the turning point in the 1980s; moreover, the turning point occurred 5–15 years earlier in large cities than in small cities. We further attribute the long‐term fog variations over East China to three factors: regional‐scale climate change, urbanization, and air pollution (aerosol pollution). We quantitatively show that urbanization and aerosol pollution contributed at least 1.6 times more than climate change, and their contributions varied with urban development stages. Fog was dominantly promoted by abundant aerosols (45–85%) during the slow urbanization stage, while it was dominantly inhibited by urban heat island and dry island (53–60%) effects during the rapid urbanization stage. In the 53‐year period, aerosol pollution promoted fog formation (20–40%). Key Points: Air pollution (aerosols) dominates the increase in fog days during the slow urbanization stageUrbanization dominates the decrease in fog days during the fast urbanization stageUrbanization and air pollution (aerosols) contribute at least 1.6 times more to fog variation than does climate change [ABSTRACT FROM AUTHOR]