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Abstract Surface visibility (SV), a key indicator of atmospheric transparency, is used widely in the fields of environmental monitoring, transportation, and aviation. However, the sparse distribution and limited number of SV monitoring sites make it difficult to fulfill the urgent need for spatiotemporally seamless fine-scale monitoring. Here, we developed the operational real-time SV retrieval (RT-SVR) framework for China that incorporates information from multiple data sources, including Chinese Land Data Assimilation System meteorological data, in situ observations, and other ancillary data. Seamless hourly SV data with 6.25-km spatial resolution are available in real time via the operational RT-SVR model, which was built using a two-layer stacked ensemble approach that combines multiple machine learning algorithms and a deep learning module. Sample-based cross-validation of the RT-SVR model on approximately 41.3 million data pairs revealed strong robustness and high accuracy, with a Pearson correlation coefficient (R) value of 0.95 and a root mean square error (RMSE) of 3.17 km. An additional hindcast-validation experiment, performed with continuous observations obtained over one year (approximately 20.8 million data pairs), demonstrated the powerful generalization capabilities of the RT-SVR model, albeit with slight degradation in performance (R = 0.85, RMSE = 5.28 km). The seamless hourly SV data with real-time update capability enable tracking of the generation, development, and dissipation of various low-SV events (e.g., fog, haze, and dust storms) in China. The developed framework might also prove useful for quantitative retrieval of aerosol-related parameters (e.g., PM2.5, PM10, and aerosol optical depth).

Water regime plays a determinant role in plant community development and patterns of plant zonation in wetlands. The waters located in the middle reach of the Yangtze River (China) have experienced a large decrease in wetland area from human activities for a long time, especially after the hydrological drought events in recent years. This outdoor study was conducted to clarify the morphological responses and reproductive strategy of Vallisneria spinulosa to water depth gradients (0.6 m, 1.0 m, 1.5 m) and to drawdown (down to 0.3 m). In static water, water depth of 1.0 m was the best condition for V. spinulosa to grow, manifested as high biomass of vegetative parts, tubers and sexual structures. However, V. spinulosa growing in water depth of 1.5 m was able to adapt to the decline in water depth in autumn, expressed as increased ramet number, stolon weight and belowground biomass. The low water depth of 0.6 m produced small plants with slight vegetative biomass and drawdown produced more tuber biomass. The drawdown caused a decline in vegetative ratio of V. spinulosa. Moreover, it caused an increase in clonal ratio at water levels of 1.5 m and 0.6 m, and a decline in sexual ratio at water levels of 1.5 m and 1.0 m. The results show that under the condition of relatively large fluctuations in water level, V. spinulosa will reduce the allocation of sexual biomass and increase the allocation of clonal biomass in order to cope with environmental changes so that it can proliferate better. Thus, water level changes have a great influence on the growth and reproduction of V. spinulosa.

The problem of seasonal drought has intensified in recent years. Unfortunately, dry seasons can lead to poor water quality due to nitrogen (N) accumulation, which, in turn, may result in the gradual decline or even disappearance of submerged plants. This outdoor study was conducted to determine the morphological, biomass responses and C/N metabolism of Vallisneria spinulosa to the high N content and low water level. We used two N contents (i.e., low and high) and three simulated water levels (i.e., gradual water level increase from 60 cm to 150 cm over four periods (C), low water level of 60 cm maintained for three periods followed by an abrupt increase to 150 cm in the fourth period (CE) and low water levels of 60 ± 30 cm maintained for three periods followed by an abrupt increase to 150 cm in the fourth period (E)). For the low N content, low water levels for CE and E treatments caused increased ramet number and biomass of V. spinulosa. However, for the high N content, the low water levels did not cause such big changes in V. spinulosa. High N contents demonstrated a remarkably negative influence on the biomass of each organ (included leaf, stolon, root and tuber) of V. spinulosa and flowering ramet number. For C water level, the high N content caused an increase in free-amino acid (FAA) content in stolons and leaves, and no difference in soluble carbohydrate (SC) content. For E water level, there was no significant increase in FAA content of V. spinulosa under high N treatment; furthermore, there was no significant change in SC content under high N treatment except for leaves. In conclusion, low water levels exacerbated the damage to V. spinulosa caused by high nitrogen level.

Smoke aerosols released through frequent springtime fire activity over the Indochina Peninsula (ICP) seriously affect regional air quality, climate, and human health. However, the mechanisms driving the interannual variability of these smoke aerosols are not well understood. By analyzing multi-source historical (1980–2020) smoke aerosols and meteorological reanalysis data, we explore the response of springtime smoke aerosol changes over the ICP to the interannual variability of the Indian Ocean (IO) sea-surface temperature (SST). Our findings show a positive correlation between the variability of springtime smoke aerosol loading and the preceding winter Southeast IO (SEIO) SST anomalies. Warmer SEIO SST tends to weaken the trans-equatorial flow (TEF) and the local Hadley circulation. This weakening of the TEF impedes cyclone development in the Bay of Bengal (BOB), thereby reducing southwest water vapor transport. Simultaneously, enhanced westerly winds over the northern BOB are blocked by the northwestern mountains of ICP. These winds converge and rise on the windward slopes, while descending on the leeward side with diminished humidity. Collectively, these dynamics lead to drier and hotter local meteorological conditions that favored fire-induced smoke aerosol emissions. Our findings highlight the role of the SEIO in regulating smoke aerosol variability and provide a scientific basis for developing strategies to manage smoke aerosol emissions over the ICP.

Acute myeloid leukemia (AML) is malignant hematologic tumors with frequent recurrence and cause high mortality. Its fate is determined by abnormal intracellular competitive endogenous RNA (ceRNA) network and extracellular tumor microenvironment (TME). This study aims to build a ceRNA network related to AML TME to explore new prognostic and therapeutic targets. The RNA expression data of AML were obtained from The Cancer Genome Atlas (TCGA) database. First, we used the ESTIMATE algorithm to calculate the immune cells and stromal cells infiltration scores in the TME and found that all scores were highly correlated with AML’s prognostic characteristics. Subsequently, differentially expressed mRNAs and lncRNAs between high and low score groups were identified to construct a TME-related ceRNA network. Further, the Cox-lasso survival model was employed to screen out the hub prognostic ceRNA network composed of two mRNAs (EPB41L3, COL2A1), three miRNAs (hsa-mir-26a-5p, hsa-mir-148b-3p, hsa-mir-148a-3p), and two lncRNAs (CYP1B1-AS1, C9orf106), and construct nomograms. Finally, we used CIBERSORT algorithm and Kaplan-Meier survival analysis to identify the prognostic TME immune cells and found that naive B cells, M2-type macrophages, and helper follicular T cells were related to prognosis, and the hub ceRNAs were highly correlated with immune cell infiltration. This study provided a new perspective to elucidate how TME regulates AML process and put forward the new therapy strategies combining targeting tumor cells with disintegrating TME.

Retinal pigment epithelium (RPE) cellular senescence is an important etiology of age-related macular degeneration (AMD). Aging interventions based on the application of stem cells to delay cellular senescence have shown good prospects in the treatment of age-related diseases. This study aimed to investigate the potential of the embryonic stem cells (ESCs) to reverse the senescence of RPE cells and to elucidate its regulatory mechanism. The hydrogen peroxide (H2O2)-mediated premature and natural passage-mediated replicative senescent RPE cells were directly cocultured with ESCs. The results showed that the proliferative capacity of premature and replicative senescent RPE cells was increased, while the positive rate of senescence-associated galactosidase (SA-β-GAL) staining and levels of reactive oxygen species (ROS) and mitochondrial membrane potential (MMP) were decreased. The positive regulatory factors of cellular senescence (p53, p21WAF1/CIP1, p16INK4a) were downregulated, while the negative regulatory factors of cellular senescence (Cyclin A2, Cyclin B1, Cyclin D1) were upregulated. Furthermore, replicative senescent RPE cells entered the S and G2/M phases from the G0/G1 phase. TGFβ (TGFB1, SMAD3, ID1, ID3) and PI3K (PIK3CG, PDK1, PLK1) pathway-related genes were upregulated in premature and replicative senescent RPE cells after ESCs application, respectively. We further treated ESCs-cocultured premature and replicative senescent RPE cells with SB531542 and LY294002 to inhibit the TGFβ and PI3K pathways, respectively, and found that p53, p21WAF1/CIP1 and p16INK4a were upregulated, while Cyclin A2, Cyclin B1, Cyclin D1, TGFβ, and PI3K pathway-related genes were downregulated, accompanied by decreased proliferation and cell cycle transition and increased positive rates of SA-β-GAL staining and levels of ROS and MMP. In conclusion, we demonstrated that ESCs can effectively reverse the senescence of premature and replicative senescent RPE cells by a direct coculture way, which may be achieved by upregulating the TGFβ and PI3K pathways, respectively, providing a basis for establishing a new therapeutic option for AMD.

Cutaneous melanoma is the most life-threatening skin malignant tumor due to its increasing metastasis and mortality rate. The abnormal competitive endogenous RNA network promotes the development of tumors and becomes biomarkers for the prognosis of various tumors. At the same time, the tumor immune microenvironment (TIME) is of great significance for tumor outcome and prognosis. From the perspective of TIME and ceRNA network, this study aims to explain the prognostic factors of cutaneous melanoma systematically and find novel and powerful biomarkers for target therapies. We obtained the transcriptome data of cutaneous melanoma from The Cancer Genome Atlas (TCGA) database, 3 survival-related mRNAs co-expression modules and 2 survival-related lncRNAs co-expression modules were identified through weighted gene co-expression network analysis (WCGNA), and 144 prognostic miRNAs were screened out by univariate Cox proportional hazard regression. Cox regression model and Kaplan-Meier survival analysis were employed to identify 4 hub prognostic mRNAs, and the prognostic ceRNA network consisting of 7 lncRNAs, 1 miRNA and 4 mRNAs was established. After analyzing the composition and proportion of total immune cells in cutaneous melanoma microenvironment through CIBERSORT algorithm, it is found through correlation analysis that lncRNA-TUG1 in the ceRNA network was closely related to the TIME. In this study, we first established cutaneous melanoma’s TIME-related ceRNA network by WGCNA. Cutaneous melanoma prognostic markers have been identified from multiple levels, which has important guiding significance for clinical diagnosis, treatment, and further scientific research on cutaneous melanoma.

Landfill leachate concentrates is the waste solution trapped by nanofiltration/reverse osmosis (NF/RO) membrane in the biochemical effluent of landfill leachate. It has high content of salt and dissolved organic matter (DOM), especially refractory organic matter. Electrochemical oxidation of landfill leachate concentrates on Ti/RuO2-Ir/O2 anode, the electrolysis time and current density and plate distances was studied on the effects of the oxidation results. The results showed that, under the optimal conditions with initial pH value 7.8, current density 8 A/dm2, plate distances 1 cm, and electrolysis time 4 h, the chroma, COD, ammonia nitrogen and Cl- removal rates were 100%, 100%, 98% and 52%respectively. UV-vis spectrum analysis showed that the aromatization degree and relative molecular mass and polymerization degree decreased of DOM in the landfill leachate concentrates after electrolysis treatment. 3D-excitation emission matrix fluorescence spectra (3D-EEMFS) showed that humic acid was oxidized to humic acid with simpler structure and smaller relative molecular mass and soluble microbial degradation by-products in the landfill leachate concentrates after electrolysis treatment. FTIR analysis showed that the absorption intensity of organic compounds in the landfill leachate concentrates decreased and most organic compounds were oxidized and degraded after electrolysis treatment. [ABSTRACT FROM AUTHOR]

The safety of the direct reuse of the sludge water and the economic benefits of the direct reuse of the sludge water are analyzed by testing the conventional (e.g. pH, turbidity and NH3-N), organic matter (e.g. CODMn and UV254) and metal indicators (e.g. Al, Fe and Mn) of effluent water quality after the direct reuse of the sludge discharged from the sedimentation tank and by using Zeta potential and particle size distribution analysis. Results show that the direct reuse of the sludge water can enhance the effect of coagulation, that is, after reuse, CODMn will not exceed the standard and has a good removal effect. However, it has minimal effect on UV254 and will not change the classification of soluble substances in raw water. The turbidity, NH3-N, Al, Fe, and Mn of the after-sedimentation water all meet the effluent quality standards under an appropriate reflux ratio. Under controlled reflux ratio conditions, the sludge water can be reused directly, thereby not only saving water resources and bringing economic benefits to the water plant but also protecting the environment to achieve the environmental protection, energy conservation and emission reduction. [ABSTRACT FROM AUTHOR]

Sediments and overlying water were collected from 12 conventional lake sites and 5 conventional estuary sites to study the distribution and influencing factors of various nitrogen forms in sediments of different areas of Poyang Lake during the dry season. The sediment nitrogen is divided into ion-exchangeable nitrogen (IEF-N), weak acid-extractable nitrogen (WAEF-N), strong alkaline-extractable nitrogen (SAEF-N), strong oxidant-extractable nitrogen (SOEF-N) and non-transformable (NTN) by sequential extraction methods. Redundancy analysis and Pearson correlation coefficient are used to study the relationship between the physicochemical properties of sediment and overlying water and the various nitrogen forms. Results show that the sediment total nitrogen (TN) content is 480.79-3933.00 mg/kg, with a mean value of 2441.82 mg/kg, of which transformable nitrogen (TTN) accounts for 24.77% of TN. The contents of each TTN are in the order of SAEF-N > IEF-N > WAEF-N > SOEF-N. Except WAEF-N and SOEF-N, the distribution of IEF-N and SAEF-N is consistent with that of TN, which is in the order of central lake > northern lake > estuary. The distribution of nitrogen forms in the sediments is significantly influenced by the physicochemical properties of overlying water and sediments in Poyang Lake in winter, especially the DO and Chl-a in the overlying water, and TP and Chl-a in sediments. [ABSTRACT FROM AUTHOR]

In order to explore the variation law of pollutants in different underlying surfaces with time, a university in Nanchang was selected as the research area. Four types of underlying surfaces in this university, namely, the main road of the whole school, the main road of the student dormitory area, school leisure square and student dormitory roof, were selected for analysis. Under the circumstance of a single rainfall, the variation law of Suspended Solids (SS), Chemical Oxygen Demand (COD), Total Nitrogen (TN) and Total Phosphorus (TP) pollutants in the four aforementioned underlying surfaces with rainfall time was analyzed to figure out the variation process of pollutants with rainfall duration. The results have shown that the variation range and variation law of water quality were different for varied underlying surfaces and rainfalls. The pollutant concentration of rainfall runoff on the whole showed an attenuation trend, and the attenuation rate was fast in the early stage and became slower in the late stage. Finally, the main pollutants in rainfall runoff of four different underlying surfaces were obtained via analysis. [ABSTRACT FROM AUTHOR]