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[Display omitted] Autosomal dominant polycystic kidney disease (ADPKD) is a common monogenic kidney disease. Emerging research indicates that the Notch signaling pathway plays an indispensable role in the pathogenesis of numerous kidney diseases, including ADPKD. Herein, we identified that Notch3 but not other Notch receptors was overexpressed in renal tissues from mice with ADPKD and ADPKD patients. Inhibiting Notch3 with γ-secretase inhibitors, which block a proteolytic cleavage required for Notch3 activation, or shRNA knockdown of Notch3 significantly delayed renal cyst growth in vitro and in vivo. Subsequent mechanistic study elucidated that the cleaved intracellular domain of Notch3 (N3ICD) and Hes1 could bind to the PTEN promoter, leading to transcriptional inhibition of PTEN. This further activated the downstream PI3K-AKT-mTOR pathway and promoted renal epithelial cell proliferation. Overall, Notch3 was identified as a novel contributor to renal epithelial cell proliferation and cystogenesis in ADPKD. We envision that Notch3 represents a promising target for ADPKD treatment. [ABSTRACT FROM AUTHOR]

Neonicotinoids have been often detected in aquatic environment with high concentrations; however, little is known about their risk and fate to/in fish. This study systematically investigated the bio-uptake, tissue distribution and metabolism of neonicotinoids in zebrafish, taking clothianidin (CLO) as an example. The results revealed the uptake and elimination kinetics of CLO in whole fish and different tissues was very similar, and its bioconcentration factor (<1) indicates the low bioaccumulation potential in zebrafish. The highest accumulative tissues for CLO were found to be intestine and liver. Eight biotransformation products were identified in intestine and liver, and the metabolic pathways were found to be N-demethylation and nitro-reduction. The metabolic kinetics of two products (desmethyl clothianidin and clothianidin urea) revealed the metabolism of CLO mainly occurred in liver and intestine. This suggested that the hepatobiliary system played an important role in the metabolism and elimination of CLO. This study provides a comprehensive evaluation of the toxicokinetics of CLO in zebrafish, and these results can contribute to its ecological risk assessment. [Display omitted] • Clothianidin (CLO) shows a low bioaccumulation potential in zebrafish. • The highest accumulative tissues for CLO in zebrafish are intestine and liver. • The proposed metabolic pathways for CLO are N-demethylation and nitro-reduction. • Hepatobiliary system plays a vital role in the metabolism and elimination of CLO. [ABSTRACT FROM AUTHOR]

Abstract: A kind of aromatic polyamide (PA) film containing phenylphosphine oxide group (PPO) was prepared. The experiment results indicated that the incorporation of the PPO group protects the PA film from eroding by atomic oxygen (AO), as compared with a kind of common aromatic polyamide (PA) without PPO groups. The chemical composition, surface morphology, mass loss, optical properties and tensile strength of the two samples, before and after AO irradiation, were compared in detail. XPS results indicated that, during the AO exposure, a passive phosphate rich layer, which protected the following under-layer from attacking by AO, was formed on the PA surface with PPO segments. SEM micrographs showed the surface morphology of both films changed intuitively. However, the PA with PPO segments didn''t take out so much surface change during the irradiation. The surface of PA was changed from smooth before irradiation, to a carpet-like character after 2 h irradiation and to a tree-root feature after 6 h irradiation. PA film with PPO segments also turned out lower mass change, less tensile strength reduction, and higher transmission after the AO irradiation as compared with the common PA film. [Copyright &y& Elsevier]

Implementing water-saving agriculture is an important measure to alleviate water resource shortage, improve agricultural ecological environment, and achieve sustainable agricultural development. However, both water-saving service companies (WSSCs) and farmers often lack the motivation to adopt water-saving practices due to the high implementation costs involved. To overcome this shortcoming, this study aims to design a blockchain-driven incentive mechanism based on the evolutionary game theory, in which the government, WSSCs and farmers are game subjects and the idea of cooperative incentive for the government is introduced. Through analyzing the complex interactions among various stakeholders and agricultural water-saving incentives, some findings of this study are obtained. Firstly, the usage of blockchain technology (BT) in the incentive mechanism for agricultural water-saving is reflected in supervision and additional default costs, which promote the sustainable cooperation among government, WSSCs and farmers in varying degrees. Secondly, the additional default costs brought by the usage of BT have a deterrent effect on WSSCs and farmers, which makes them to actively implement water-saving practices. Thirdly, the additional default cost brought by BT has become the main basis for the government to choose BT supervision. As the additional default cost increases, the government are not more inclined to use BT. It provides valuable insights into motivating diverse stakeholders to actively participate in water-saving practices, promoting sustainable water resources management in agriculture. [ABSTRACT FROM AUTHOR]

Autosomal dominant polycystic kidney disease (ADPKD) is a common monogenetic disease characterized by progressive development of renal cysts that leads to end stage renal disease. The aim of this study was to investigate the effect of Ganoderma triterpenes (GT), extracts from the natural product Ganoderma lucidum , on the development of kidney cysts. Our study revealed that GT significantly inhibited cyst growth in a dose-dependent manner in an in vitro cystogenesis model and an embryonic kidney cyst model. More importantly, GT was shown to attenuate the progression of cyst and reduce kidney mass in two ADPKD mouse models. To understand the underlying cyst-inhibiting mechanism of GT, a tubulogenesis assay was performed and showed that GT promoted epithelial tubule formation in MDCK cells, suggesting a possible effect on epithelial cell differentiation. The role of GT in regulating key signalling pathways that are involved in the pathogenesis of PKD was further investigated by immunoblotting. Our data revealed that GT specifically downregulated forskolin-induced activation of the Ras/MAPK signalling pathways in MDCK cells without a detectable effect on the mTOR pathway. We further screened 15 monomers that were purified from GT for their effects on inhibiting cyst formation in vitro . We demonstrated that CBLZ-7 (ethyl ganoderate C 2 ) had a potent inhibitory effect on cyst formation in vitro . In addition, like GT, CBLZ-7 was able to downregulate FSK induced activation of the Ras/MAPK pathway. Therefore, our study demonstrated that GT and its purified monomer, CBLZ-7, are potential therapeutic regents for treating cystic kidney diseases. [ABSTRACT FROM AUTHOR]

In this communication we demonstrate the role of turbulence intensity in the dual-front structure and self-similar propagation of spherical turbulent iron-methane hybrid flames. We first show that iron-methane hybrid mixture, whose iron concentration is below a critical threshold for the formation of a dust flame front in laminar or weak turbulent environment, can be burned strongly with both separated dual-front and merged single-front structures in intense turbulence. It is suggested that the formation of iron flame front would be attributed to local iron concentration accumulation by preferential sampling with near-unity Stocks number (St), heat transfer enhancement of iron particles to fluid and mixing promotion of iron particles with oxidants by strong turbulence. The propagation of iron front falls behind the methane front in the leading segments which is promoted by flame stretch for sub-unity Lewis number (Le), thus the separated dual-front structure occurs. Furthermore, the strong self-similar propagation of spherical turbulent iron-methane hybrid flame was observed under different turbulence intensities (u rms). Mechanistically, such strong self-similar propagation of the hybrid flame is the consequence of the couple effects of flame mode transition at high u rms with near-unity St and differential diffusion for sub-unity Le. [ABSTRACT FROM AUTHOR]

This study investigated the flame propagation and turbulent burning velocity of hydrogen/n-heptane/air mixtures subjected to differential diffusion and flame stretch induced by turbulence at different hydrogen molar fractions (X H2 = 0–100%), equivalence ratios (ϕ = 0.5–1.0) and turbulence intensities (u' = 0–3.62 m/s). The experiments were carried out on a medium-scale, fan-stirred cylindrical combustion chamber generating near-isotropic turbulence. Results show that as hydrogen content increases, the turbulent flame propagation speed tends to be affected by stronger differential diffusion and weakened turbulence, characterized by decreasing Lewis number (Le) and Karlovitz number (Ka) within a similar range of turbulence intensity. Among them, the effect of differential diffusion on the normalized turbulent propagation speed (d < r > / d t σ S L ) appears to be well correlated with Re T,flame Le -2, where Re T,flame represents the turbulent flame Reynolds number. However, inconsistencies in the fitting parameters for this scale are observed at different X H2 , highlighting the impact of substantial variations in flame stretch induced by turbulence. Therefore, the normalized turbulent flame propagation velocity under varying hydrogen contents is proposed to be accurately predicted by d < r > / d t σ S L -1 = 0.07 K a 0.32 (R e T , flame L e − 2) 0.5 . The synergistic effects of Le and Ka can also account for the peak phenomenon in the normalized turbulent burning velocity (S T / S L) observed at 85% hydrogen content. Furthermore, the quantitative characterization of turbulence and differential diffusion under extensive experimental data (Ka = 0.03–90) is studied. As evidenced by the Damköhler theoretical hypothesis, the two-stage trend between S T / S L and (u' / S L) Le -1 is identified with a transition near unity Ka. The modified correlations for turbulent burning velocity in terms of (u' / S L) Le -1 and Ka 0.2 are obtained with consideration of the differential diffusion and flame stretch rate induced by turbulence, which show good predictive performance for data at different turbulence regime diagrams regardless of fuel type and equipment size. [ABSTRACT FROM AUTHOR]

Abstract The hydrated electron (e aq −)-based reduction processes are promising for removing organic pollutants in water engineering systems. The reductive kinetics, especially the second order rate constants ( k e aq − ) of e aq − with organic compounds, is important for evaluating and modeling the advanced reduction processes. In this study, the k e aq − values for aliphatic compounds and phenyl-based compounds are, for the first time, modeled by the quantitative structure-activity relationship (QSAR) method. The structural features governing the reactivity of two classes of organic compounds toward e aq − were revealed, and the energy of the lowest unoccupied molecular orbital (E LUMO) , one-electron reduction potential (E RED) and polarizability (α) were found to be the important molecular parameters in both two models. The built QSAR models provide robust predictive tools for estimating the removal of emerging pollutants using e aq − during wastewater treatment processes. Additionally, quantum chemical calculations were employed to probe into the mechanism and feasibility of the single electron transfer (SET) pathway in the e aq −-based reduction process. The thermodynamic investigation suggests that the compounds with electron-withdrawing groups tend to possess higher k e aq − and lower Gibbs free energy (Δ G SET) and Gibbs free energies of activation (∆ ‡ G SET ∘) than the ones with electron-donating groups, indicating the SET process occurs more readily. It is also found that the refractory halogenated compounds can achieve dehalogenation via the SET pathway. Graphical abstract Image 1 Highlights • We developed QSAR models to predict e aq − reaction rate constants ( k e aq − ). • E LUMO is the most important molecular parameter governing the reactivity with e aq −. • Compounds with electron withdrawing groups possess higher reactivities with e aq −. • Compounds with electron withdrawing groups have lower Δ ‡ G S E T ° , Δ G SET and Δ H SET. [ABSTRACT FROM AUTHOR]

Insecticides are widely used in crop protection against insects and frequently detected in aquatic environment. Photolysis kinetics are directly related with exposure assessment and risk assessment. However, the photolysis mechanism of neonicotinoid insecticides with different structures has not been studied and compared systematically in the literature. In this paper, the photolysis rate constants in water were determined for eleven insecticides under irradiation of simulated sunlight. At the same time, the photolysis mechanism and effect of dissolved organic matter (DOM) on their photolysis were studied. The results showed that photolysis rates of eleven insecticides vary in a large range. The photolysis rates of nitro-substituted neonicotinoids and butenolide insecticide are much faster than that of cyanoimino-substituted neonicotinoids and sulfoximine insecticide. The ROS scavenging activity assays reveal that direct photolysis dominates the degradation of seven insecticides and, on the other hand, self-sensitized photolysis dominates four insecticides. The shading-effect from DOM can reduce the direct photolysis rates, on the other hand, ROSs generated by triplet-state DOM (3DOM*) can also accelerate photolysis of insecticides. According to the photolytic products identified from HPLC-MS, these eleven insecticides have different photolysis pathways. Six insecticides are degraded from the removal of nitro group from their parent compounds and four insecticides are degraded through ·OH reaction or singlet oxygen (1O 2) reaction. QSAR (quantitative structure-activity relationship) analysis showed that photolysis rate was directly related to the energy gap between the highest occupied molecular orbital to the lowest unfilled molecular orbital (E gap = E LUMO − E HOMO) and dipole moment (δ). These two descriptors reflect the chemical stability and reactivity of insecticides. The pathways developed from identified products and the molecular descriptors of QSAR models can well verify the photolysis mechanisms of eleven insecticides. [Display omitted] • The photolysis rate constants have been measured for eleven neonicotinoid insecticides. • The direct photolysis dominates the degradation of seven out of eleven insecticides. • Addition of ROS scavengers can significantly decrease photolysis rates of four insecticides. • Photolysis mechanisms have been verified from the photolysis pathways for eleven insecticides. • QSAR models reflect the photolysis mechanisms of eleven insecticides. [ABSTRACT FROM AUTHOR]

[Display omitted] • Enantiomers of TF show no stereoselective photolysis and photo-induced toxicity. • TN diastereomers show stereoselective photolysis and photo-induced toxicity. • Individual chiral monomers possess similar photolysis mechanism as the mixture. • Main photolytic pathways for TF and TN are removal of Cl and triazole groups. • Chiral mixture and monomers exhibit enhanced photo-induced toxicity to V. fischeri. The photochemical behaviors of chiral pollutants in aqueous solutions are rarely studied using chiral monomers, which may hamper their precise risk assessment and lead to suspicious conclusions. In this study, we systematically investigated the phototransformation behavior and toxicity evolution of two widely used chiral pesticides (triadimefon (TF) and triadimenol (TN)) at enantiomer and diastereomer levels, and proposed a calculation method of total photolysis rate constants of chiral mixture. Results show that TF and TN could be photodegraded faster in pure water than in natural waters, and the observed photolysis rate constants (k obs) of TN with two chiral centers exhibit enantioselectivity, i.e., k obs (TN-RS) = k obs (TN-SR) > k obs (TN-RR) = k obs (TN-SS). The photolysis of TF and TN mainly occurs through their excited singlet and triplet states, respectively. Their photodegradation pathways mainly include dechlorination and elimination of triazole ring. TF could also undergo ether bond cleavage. It is also found that, both TF and TN exhibit photo-induced toxicity to V. fischeri , due to the generation of more toxic products than parent compounds. Furthermore, TN exhibits enantioselective photo-induced toxicity after 240-min irradiation, which could be ascribed to the formation of chiral products. These results could benefit the understanding of enantioselective environmental behavior of chiral pollutants. [ABSTRACT FROM AUTHOR]

The acute toxicity of organic pollutants to fish, Daphnia magna , Tetrahymena pyriformis , and Vibrio fischeri was investigated. The results indicated that the Toxicity Ratio (TR) threshold of log TR = 1, which has been based on the distribution of toxicity data to fish, can also be used to discriminate reactive or specifically acting compounds from baseline narcotics for Daphnia magna and Vibrio fischeri . A log TR = 0.84 is proposed for Tetrahymena pyriformis following investigation of the relationships between the species sensitivity and the absolute averaged residuals (AAR) between the predicted baseline toxicity and the experimental toxicity. Less inert compounds exhibit relatively higher toxicity to the lower species ( Tetrahymena pyriformis and Vibrio fischeri ) than the higher species (fish and Daphnia magna ). A greater number of less inert compounds with log TR greater than the thresholds was observed for Tetrahymena pyriformis and Vibrio fischeri . This may be attributed to the hydrophilic compounds which may pass more easily through cell membranes than the skin or exoskeleton of organisms and have higher bioconcentration factors in the lower species, leading to higher toxicity. Most of classes of chemical associated with excess toxicity to one species also exhibited excess toxicity to other species, however, a few classes with excess toxicity to one species exhibiting narcotic toxicity to other species and thus may have different MOAs between species. Some ionizable compounds have log TR much lower than one because of the over-estimated log K OW . The factors that influence the toxicity ratio calculated from baseline level are discussed in this paper. [ABSTRACT FROM AUTHOR]

Clarifying the impact of human activities on polycyclic aromatic hydrocarbons (PAHs) in soil can provide a scientific basis to reduce PAHs pollution and formulate control measures to manage soil PAHs pollution, which are important to reduce global warming and support China's implementation of carbon neutrality goals. Here, we characterize the PAHs in 1055 samples of urban soil collected in China from 2000 to 2020. The total concentration of PAHs ranged from 2.75 to 38,865 ng g−1. PAHs concentrations in the Yangtze River Delta (YangtzeD) and Pearl River Delta exhibited an inverted U-shaped curve over time, and PAHs concentrations in Beijing have decreased. Air pollution prevention policies and vehicle emission standards in these regions reduced PAHs in the soil. We measured PAHs in soils of 18 major cities in YangtzeD, representing a typical area. Total concentration of PAHs was 3.88–2153 ng g−1 in YangtzeD, with 40.5%, 36.3%, and 23.2% of PAHs coming from industry and transportation, coal combustion, and biomass combustion, respectively by Positive matrix factorization (PMF) model. To explore how human activities affect the PAH concentrations, we screened three machine learning models and selected SHapley Additive explanation-extreme gradient boosting (XGB-SHAP) as the best model. The results of XGB-SHAP (R2 = 0.64) show that the main human activities affecting PAHs were carbon emissions, population size, and economic development (MAS = 709.1) and industrial waste gas emissions (MAS = 577.1), and these were positively correlated with PAHs. Therefore, effective ways to reduce PAHs may largely rely on industrial co-control. With the prevention and control of air pollution, clean energy, and green and low-carbon development policies constantly being implemented, PAH concentrations will continue to be reduced in the future. [ABSTRACT FROM AUTHOR]

Aquaporin-3 (AQP3), a transporter of water, glycerol and H 2 O 2 , is expressed in basolateral membranes of principal cells in kidney collecting duct. Here, we report that AQP3 deletion in mice affects renal function and modulates renal injury. We found collecting duct hyperplasia and cell swelling in kidneys of adult AQP3 null mice. After mild renal ischemia-reperfusion (IR), AQP3 null mice had significantly greater blood urea nitrogen (57 mg/dl) and creatinine (136 μM) than wild-type mice (35 mg/dl and 48 μM, respectively), and showed renal morphological changes, including tubular dilatation, erythrocyte diapedesis and collecting duct incompletion. MPO, MDA and SOD following IR in AQP3 null mice were significantly different from that in wild-type mice (1.7 U/g vs 0.8 U/g, 3.9 μM/g vs 2.4 μM/g, 6.4 U/mg vs 11 U/mg, respectively). Following IR, AQP3 deletion inhibited activation of mitogen-activated protein kinase (MAPK) signaling and produced an increase in the ratios of Bax/Bcl-2, cleaved caspase-3/caspase-3 and p-p53/p53. Studies in transfected MDCK cells showed that AQP3 expression attenuated reduced cell viability following hypoxia-reoxygenation, with reduced apoptosis and increased MAPK signaling. Our results support a novel role for AQP3 in modulating renal injury and suggest the mechanisms involved in protection against hypoxic injury. [ABSTRACT FROM AUTHOR]

Although modes of action (MOAs) play a key role in the understanding of the toxic mechanism of chemicals, the MOAs have not been investigated for antibiotics to green algae. This paper is to discriminate excess toxicity from baseline level and investigate the MOAs of 13 different antibiotics to algae by using the determined toxicity values. Comparison of the toxicities shows that the inhibitors of protein synthesis to bacteria, such as azithromycin, doxycycline, florfenicol and oxytetracycline, exhibit significantly toxic effects to algae. On the other hand, the cell wall synthesis inhibitors, such as cefotaxime and amoxicillin, show relatively low toxic effects to the algae. The concentrations determined by HPLC indicate that quinocetone and amoxicillin can be easily photodegraded or hydrolyzed during the toxic tests. The toxic effects of quinocetone and amoxicillin to the algae are attributed to not only their parent compounds, but also their metabolites. Investigation on the mode of action shows that, except rifampicin, all the tested antibiotics exhibit excess toxicity to Pseudokirchneriella subcapitata ( P. subcapitata) . These antibiotics can be identified as reactive modes of action to the algae. They act as electrophilic mechanism of action to P. subcapitata . These results are valuable for the understanding of the toxic mechanism to algae. [ABSTRACT FROM AUTHOR]

Autosomal dominant polycystic kidney disease (ADPKD) is a monogenetic disease that still lacks effective therapy. Repulsive guidance molecule b (RGMb), a co-receptor for bone morphogenetic proteins (BMPs) and a ligand for neogenin, is expressed in renal tubular epithelial cells. Previous studies showed that RGMb plays negative roles in several types of tumors and prevents the immune system from over activation. The present study was designed to explore the effects of RGMb in ADPKD development. We found that expression of RGMb in kidney was less in PKD mice than wild-type mice. With stimulation of 8-bromo-cAMP, RGMb-null embryonic kidneys had greater cyst index, though their ureteric bud branched less than wild-type mice at E13.5. Postnatal RGMb-null kidneys showed interstitial hyperplasia and decreased tubular structures, especially in the boundary area of renal cortex and medulla. RGMb overexpression dramatically inhibited cyst development and promoted tubulogenesis in MDCK cells grown in 3D collagen gels. Biochemical analysis showed increased p-Smad1/5/8 and decreased p-ERK in RGMb-overexpressing MDCK cells, suggesting modulated BMP signaling. Specific inhibition of p-Smad1/5/8 by LDN193189 reversed the suppression of RGMb on MDCK cyst model. These results reveal RGMb as a novel regulator for ADPKD by promoting renal tubule branching and regulating BMP signaling pathway. Elevating RGMb and enhancing p-Smad1/5/8 are promising new strategies to treat ADPKD. [ABSTRACT FROM AUTHOR]

• A significant interspecies correlation equation has been developed between tadpole and worm toxicities. • A theoretical equation has been developed to explain the QSAR models. • Insecticides and fungicides can be classified as specifically-acting compounds to both tadpoles and worms. • Worms are more sensitive than tadpoles for reactive compounds because of their polar property. • Ionic compounds exhibit low toxicity to tadpoles and worms because of their poor bio-uptake potential. Insecticides, fungicides, dinitrobenzenes, resorcinols, phenols and anilines are widely used in agricultural and industrial productions. However, their modes of toxic action are unclear in some nontarget organisms, such as worms and tadpoles. In this study, acute toxicity data was experimentally collected for Limnodrilus hoffmeisteri worms and Rana chensinensis tadpoles, respectively. Interspecies correlation and excess toxicity were calculated to determine modes of action (MOAs) between the two species for class-based compounds. The result showed that, although the interspecies correlation of toxicity between the tadpoles and worms is significant with a coefficient of determination (R2) of 0.83, tadpoles are more sensitive than the worms and toxicity values between these two species are not identical with an overall 0.43 log unit difference. Regression analysis revealed that the toxicity of nonpolar narcotics or baseline compounds is linearly related to hydrophobicity for both the tadpoles and worms and the two baseline models are parallel, suggesting that these nonpolar narcotics share the same MOA between the two species. The difference of baseline toxicities between the two species is attributed to differences in bioconcentration factors. Analysis of the excess toxicity calculated from the toxicity ratio (TR) suggested that phenols and anilines can be classified as polar narcotics, not only to fish, but also to the tadpoles and worms. These compounds are more toxic than the baseline compounds and quantitative structure-activity relationship (QSAR) models show that their toxicity is linearly related to chemical hydrophobicity and polarity. Analysis of the excess toxicity reveals that aminophenols and resorcinols can be classified as reactive compounds, and insecticides and fungicides can be classified as specifically-acting compounds for both species. These compounds exhibited significantly greater toxic effect to both the tadpoles and worms. QSAR models have been developed to describe the toxic mechanisms for nonpolar narcotics, polar narcotics, reactive chemicals and specifically-acting compounds, and a theoretical equation has been derived to explain the effect of bio-uptake and interaction of the chemical with target receptors for both tadpole and worm toxicity. Our study reveals that tadpole toxicity can be estimated from worm toxicity data and the two species can serve as surrogates for each other in the safety evaluation of organic pollutants. [ABSTRACT FROM AUTHOR]

Neonicotinoids are widely used pesticides all over the world and pose severe water pollution. Although they can be degraded via absorbing sunlight, few attentions have been paid to the environmental risks of their photolysis products. In this paper, the photo-toxicity was investigated for four neonicotinoids (dinotefuran, nitenpyram, thiamethoxam and clothianidin) based on a series of experiments (i.e., photolysis kinetics, radical scavenging, bioluminescent inhibition test to Vibrio Fischeri and intermediate identification) and in-silico calculation of photolysis pathway. The results show that direct photolysis dominates the photolysis of the four neonicotinoids under simulated sunlight radiation. The bioluminescent inhibition kinetics shows that all four neonicotinoids have photo-induced toxicity to V. fischeri , but with different light-induced responses. Scavenging radicals (·OH and 1O 2) will decrease the photo-induced toxicity of all the four neonicotinoids, indicating radicals play important roles to the photo-chemical reactions of intermediates. Dissolved organic matters exhibit slightly shading effect to the photolysis rates of four parent compounds. However, the ROSs generated by DOM can accelerate the photo-chemical reactions of intermediates, leading to different photo-induced toxicity in present of DOM. According to the detected intermediates and Gaussian calculations, there are different photolysis pathways and mechanisms for the four neonicotinoids. The calculation for photo-sensitization reactions with 3O 2 indicates that both energy transfer reactions and electron transfer reactions can be produced under simulated sunlight radiation, which further consolidate that reactive oxygen species are involved in the photolysis process. A theoretical model has been developed to explain the toxicity variations of four neonicotinoids in different aqueous conditions. [Display omitted] • All the four neonicotinoids exhibit the photo-induced toxicity to V. fischeri , but with different toxic response. • ROSs are involved in and play important roles in the photo-chemical transformation of intermediates. • The amounts of ROSs play key roles in the photo-induced toxicity variation for the four neonicotinoids in different solution. • A developed theoretical equation can well explain the toxicity variations of four neonicotinoids to V. fischeri. [ABSTRACT FROM AUTHOR]

Highlights: [•] The mode of toxic action of chemicals is species dependent. [•] Same threshold needs to be used for the discrimination of excess toxicity from narcotic effect. [•] Not all the reactive compounds exhibit excess toxicity. [•] Discrimination of less inert compounds from baseline is difficult for hydrophobic compounds. [•] Bioconcentration and experimental uncertainty can lead to mis-classification of category. [Copyright &y& Elsevier]

Abstract: Prediction of the biodegradability of organic pollutants is an ecologically desirable and economically feasible tool for estimating the environmental fate of chemicals. In this paper, linear and nonlinear relationships between biological oxygen demand (BOD) and molecular descriptors/fragments have been investigated for 1130 organic chemicals. Significant relationships have been observed between the simple molecular descriptors and %BOD for some homologous compounds, but not for the whole set of compounds. Electronic parameters, such as EHOMO and ELUMO, are the dominant factors affecting the biodegradability for some homologous chemicals. However, other descriptors, such as molecular weight, acid dissociation constant and polarity still have a significant impact on the biodegradation. The best global model for %BOD prediction is that developed from a chain-based fragmentation scheme. At the same time, the theoretical relationship between %BOD and molecular descriptors/fragments has been investigated, based on a first-order kinetic process. The %BOD is nonlinearly, rather than linearly, related to the descriptors. The coefficients of determination can be significantly improved by using nonlinear models for the homologous compounds and the whole data set. After analysing 1130 ready and not ready biodegradable compounds using 23 simple descriptors and various fragmentation schemes, it was revealed that biodegradation could be well predicted from a chain-based fragmentation scheme, a decision tree and a %BOD model. The models were capable of separating NRB and RB with an overall accuracy of 87.2%, 83.0% and 82.5%, respectively. The best classification model developed was a chain-based model but it used 155 fragments. The simplest model was a decision tree which only used 10 structural fragments. The effect of structures on the biodegradation has been analysed and the biodegradation pathway and mechanisms have been discussed based on activating and inactivating fragments. [Copyright &y& Elsevier]

[Display omitted] • Various indices and PMF were used to explore contaminations, health risk and sources of metals heavy metal. • 86.91% of sampling points in the soil belong to moderate, high and extreme ecological risks. • Carcinogenic and non-carcinogenic risks of heavy metals to the human body are insignificant. • The four main sources mainly include natural sources, transportation sources, agricultural sources and industrial sources. For the purpose of pollution assessment, human health risk assessment and quantitative source apportionment of heavy metals in cultivated soils, a total of 382 cultivated soil samples were collected from cultivated of Lanzhou in September 2019. Various indices, including pollution index (PI), Nemerow integrated pollution index (NIPI) and potential ecological risk index (RI) were used to analyze the pollution levels caused by heavy metals. Human health risk assessment, geographic information system (GIS) and positive matrix factorization (PMF) receptor modeling were employed to analyze the human health risk and source of heavy metals. The results showed that mean concentrations of Hg exceeded the national soil pollution risk screening value (GB 15618–2018). Spatially, except Cr in the study area, Pb, Cd, As, Cu, Zn and Ni have high value in Chengguan and Qilihe. Hg has high values in study areas outside Chengguan, Anning and Qilihe. The Nemerow integrated pollution index showed that the moderate and severe samples sites were 37.70% and 3.66%, respectively. The potential ecological risk indicates that most of the sampling sites are moderate risks. According to the health risk assessment results, the carcinogenic and non-carcinogenic risks of heavy metals to the human body are insignificant. Based on positive matrix factorization, there are four main sources of eight heavy metals. Pb, Cd, Zn and Ni were attributed to traffic sources; Hg were closely related to agricultural activities and medical treatment; Cr, Cu and Ni originated from natural source, As was derived from industrial activity. In this study enhance understanding of the pollution levers of heavy metals in Lanzhou cultivated soils, and also serves as reference for pollution source apportionment in other regions. [ABSTRACT FROM AUTHOR]

• Colloform pyrite has a concentric-banded texture with the core composed of granular microcrystals (~300 nm). • Colloform pyrite has abrupt changes between a random CPO and <100>, or <110> CPOs. • The growth of pyrite transform from disordered microcrystals into elongated crystals is controlled by geometrical selection. Colloform pyrite textures have been detected in various geological bodies and have received much attention in recent years. Although these textures have been proved to be formed by the aggregation of micro-grains with different sizes, further work is needed to understand the mechanism for developing them. We carried out a detailed study on the micro-textures, crystal preferred orientations (CPOs), trace element, and sulfur isotope compositions of colloform pyrite aggregates from the Baiyunpu Pb–Zn deposit in Hunan, China. Results showed that the inner core of colloform pyrite had an irregular outline with flattening at their contact boundaries and was commonly formed by the compaction of multiple spherical aggregates. The outer layers concentrically grew around the core. Field emission-scanning electron microscope (FE-SEM) suggested both the inner core and the outer layers were composed of a large number of nano- or micron-scale grains (~300 nm granular crystals to acicular and elongated crystals up to ~100 μm in length). Electron backscatter diffraction (EBSD) revealed an initial random CPO in the core and either 〈1 0 0〉 or 〈1 1 0〉 CPOs in subsequent layers. In situ sulfur isotope compositions obtained by secondary-ion mass spectrometry (SIMS) showed that the δ34S values of colloform pyrite ranged from −8.4 to −0.2‰, which were interpreted to be mainly derived from thermochemical sulfate reduction (TSR). Colloform pyrite aggregates are considered to grow from the core outward through the accretion of layers, including (1) formation and aggregation of microcrystals in core A 1 and (2) growth and geometrical selection of crystals in outer layers. The growth and transformation of pyrite from disorderly granular microcrystals in the core to elongated crystals radiating from the aggregated center in the outer concentric zones is thought to be controlled by geometrical selection. Factors affecting the epitaxial relationship between the substrate and the growing crystals, such as interface energy, ambient temperature and degree of sulfur supersaturation, may control the abrupt changes in CPO recorded in colloform pyrite aggregates. [ABSTRACT FROM AUTHOR]

The ozonation-based advanced oxidation process is a promising treatment technology for wastewater with micropollutants. The second-order reaction rate constant (k O3) of ozone (O 3) with organic compounds is an important index for estimating removal efficiency of organic pollutants in engineered treatment; however, the experimental k O3 values are currently only available for hundreds of chemicals. In this study, two quantitative-structure activity relationship (QSAR) models were developed to predict k O3 of various organic chemicals with multiple linear regression (MLR) and support vector machine (SVM) methods. The built QSAR models cover a large dataset (136 chemicals) and more structurally diverse chemicals as compared to the existing models. The MLR model possesses satisfactory goodness-of-fit (R 2 tr = 0.734), robustness (Q 2 LOO = 0.700, Q 2 BOOT = 0.772) and predictive ability (R 2 ext = 0.797, Q 2 ext = 0.794), and the SVM model also has good fitness (R 2 tr = 0.862) and predictability (R 2 ext = 0.782, Q 2 ext = 0.775). The applicability domain of the models has been extended and includes chemicals (especially some emerging pollutants) that are rarely covered in many previous models. The underlying molecular structural factors influencing ozonation are revealed. The energy of the highest occupied molecular orbital (E HOMO) and the phenol/enol/carboxyl OH group (O-057) are the two most important molecular structural factors governing the reactivity of organic compounds with ozone. The developed models can serve as a prescreening tool for the removal prediction of organic pollutants by ozone. Unlabelled Image • The MLR and SVM models were developed for predicting O 3 reaction rate constants. • The built models cover a larger dataset and have broader applicability domains. • Two models possess satisfactory goodness-of-fit, robustness and predictive abilities. • The underlying molecular structural factors influencing ozonation are revealed. [ABSTRACT FROM AUTHOR]