A selective filter for cytoplasmic transport at the axon initial segment.

Distinct molecules are segregated into somatodendritic and axonal compartments of polarized neurons, but mechanisms underlying the development and maintenance of such segregation remain largely unclear. In cultured hippocampal neurons, we observed an ankyrin G- and F-actin-dependent structure that emerged in the cytoplasm of the axon initial segment (AIS) within 2 days after axon/dendrite differentiation, imposing a selective filter for diffusion of macromolecules and transport of vesicular carriers into the axon. Axonal entry was allowed for KIF5-driven carriers of synaptic vesicle protein VAMP2, but not for KIF17-driven carriers of dendrite-targeting NMDA receptor subunit NR2B. Comparisons of transport rates between chimeric forms of KIF17 and KIF5B, with the motor and cargo-binding domains switched, and between KIF5 loaded with VAMP2 versus GluR2 suggest that axonal entry of vesicular carriers depends on the transport efficacy of KIF-cargo complexes. This selective AIS filtering may contribute to preferential trafficking and segregation of cellular components in polarized neurons.

Dynamic Nomogram for Predicting the Risk of Perioperative Neurocognitive Disorders in Adults.

BACKGROUND: Simple and rapid tools for screening high-risk patients for perioperative neurocognitive disorders (PNDs) are urgently needed to improve patient outcomes. We developed an online tool with machine-learning algorithms using routine variables based on multicenter data. METHODS: The entire dataset was composed of 49,768 surgical patients from 3 representative academic hospitals in China. Surgical patients older than 45 years, those undergoing general anesthesia, and those without a history of PND were enrolled. When the patient's discharge diagnosis was PND, the patient was in the PND group. Patients in the non-PND group were randomly extracted from the big data platform according to the surgical type, age, and source of data in the PND group with a ratio of 3:1. After data preprocessing and feature selection, general linear model (GLM), artificial neural network (ANN), and naive Bayes (NB) were used for model development and evaluation. Model performance was evaluated by the area under the receiver operating characteristic curve (ROCAUC), the area under the precision-recall curve (PRAUC), the Brier score, the index of prediction accuracy (IPA), sensitivity, specificity, etc. The model was also externally validated on the multiparameter intelligent monitoring in intensive care (MIMIC) Ⅳ database. Afterward, we developed an online visualization tool to preoperatively predict patients' risk of developing PND based on the models with the best performance. RESULTS: A total of 1051 patients (242 PND and 809 non-PND) and 2884 patients (6.2% patients with PND) were analyzed on multicenter data (model development, test [internal validation], external validation-1) and MIMIC Ⅳ dataset (external validation-2). The model performance based on GLM was much better than that based on ANN and NB. The best-performing GLM model on validation-1 dataset achieved ROCAUC (0.874; 95% confidence interval [CI], 0.833-0.915), PRAUC (0.685; 95% CI, 0.584-0.786), sensitivity (72.6%; 95% CI, 61.4%-81.5%), specificity (84.4%; 95% CI, 79.3%-88.4%), Brier score (0.131), and IPA (44.7%), and of which the ROCAUC (0.761, 95% CI, 0.712-0.809), the PRAUC (0.475, 95% CI, 0.370-0.581), Brier score (0.053), and IPA (76.8%) on validation-2 dataset. Afterward, we developed an online tool (https://pnd-predictive-model-dynnom.shinyapps.io/ DynNomapp/) with 10 routine variables for preoperatively screening high-risk patients. CONCLUSIONS: We developed a simple and rapid online tool to preoperatively screen patients' risk of PND using GLM based on multicenter data, which may help medical staff's decision-making regarding perioperative management strategies to improve patient outcomes.

Retracted: Withaferin-A Inhibits Growth of Drug-Resistant Breast Carcinoma by Inducing Apoptosis and Autophagy, Endogenous Reactive Oxygen Species (ROS) Production, and Inhibition of Cell Migration and Nuclear Factor kappa B (Nf-κB)/Mammalian Target of Rapamycin (m-TOR) Signalling Pathway.

Retracted, due to breach of publishing guidelines, following the identification of non-original and manipulated figure images. Reference: Xiaokang Liu, Yu Li, Qiang Ma, Yanwei Wang, Ai Lin Song: Withaferin-A Inhibits Growth of Drug-Resistant Breast Carcinoma by Inducing Apoptosis and Autophagy, Endogenous Reactive Oxygen Species (ROS) Production, and Inhibition of Cell Migration and Nuclear Factor kappa B (Nf-kappaB)/Mammalian Target of Rapamycin (m-TOR) Signalling Pathway. Med Sci Monit 2019; 25:6855-6863. 10.12659/MSM.916931.

Chemoresistance in gastric cancer is attributed to the overexpression of excision repair cross-complementing 1 (ERCC1) caused by microRNA-122 dysregulation.

MicroRNAs are deemed as key regulators of gene expression. In particular, the elevated expression of excision repair cross-complementing 1 (ERCC1) significantly reduced the effectiveness of gastric cancer treatment by cisplatin (CDDP)-based therapies. In this paper, qRT-PCR and western blot were adopted to measure miR-122 and ERCC1 messenger RNA (mRNA) expression in all samples. Luciferase assay was carried out to verify the role of ERCC1 as a target of miR-122. The CCK-8 assay was carried out to study the effect of ERCC1 and miR-122 on cell survival and apoptosis. The results demonstrated that miR-122 expression was reduced in cisplatin-resistant gastric cancer. Using bioinformatic analysis, miR-122 was shown to target the 3'-UTR of human ERCC1. A dual-luciferase assay demonstrated that miR-122 downregulated ERCC1 expression, while the mutations in ERCC1 3'-UTR abolished its interaction with miR-122. Transfection of miR-122 mimics decreased the levels of ERCC1 mRNA and protein expression, while the transfection of miR-122 inhibitors increased the levels of both ERCC1 mRNA and protein expression. Furthermore, we found that overexpressed miR-122 promoted the proliferation of MKN74 cells and reduced their apoptotic by targeting ERCC1. In addition, the levels of miR-122 and ERCC1 were negatively correlated in gastric cancer samples. In summary, the reduced miR-122 expression may play an essential role in the induction of cisplatin-resistance by increasing ERCC1 expression.

Withaferin-A Inhibits Growth of Drug-Resistant Breast Carcinoma by Inducing Apoptosis and Autophagy, Endogenous Reactive Oxygen Species (ROS) Production, and Inhibition of Cell Migration and Nuclear Factor kappa B (Nf-κB)/Mammalian Target of Rapamycin (m-TOR) Signalling Pathway.

BACKGROUND The main purpose of this study was to assess in vitro and in vivo the anticancer effect of withaferin-A in human breast carcinoma cells (MDA-MB-231), and to assess its effects on autophagy, cell apoptosis, ROS production, cell migration and invasion, and Nf-kappaB/m-TOR signalling pathway. MATERIAL AND METHODS Proliferation of MDA-MB-231 cells at various doses of the drug was studied by CCK8 cell viability assay. Effects on cell apoptosis were studied by fluorescence microscopy in combination with flow cytometry and Western blot analysis. Effects on autophagy were evaluated by transmission electron microscopy and Western blot. Effects on cellular migration were examined in vitro by wound healing assay. RESULTS The results indicated that withaferin-A led to significant reduction of MDA-MB-231 cell viability. The anticancer action of withaferin-A was shown to be due to the stimulation of autophagy, which was accompanied by enhancement of LC3 expression. Withaferin-A prompted mitochondrial apoptosis, which was also associated with increased level of Bax and decreased Bcl-2 in MDA-MB-231 cells. It was also observed that withaferin-A has decreases cellular migration and invasion of the tested human breast cancer cells. The effects of withaferin-A were also investigated in vivo, and it was found that this molecule could inhibit the growth of tumor xenografts in tested mice. Withaferin-A led to suppression of the Nf-kappaB/m-TOR signalling pathway. CONCLUSIONS In brief, the withaferin-A molecule has great potential as an anticancer agent against drug-resistant breast cancer, and as such needs to be further studied in detail.

[A review on behavior and brain imaging research of human visually-guided action].

Bipedalism (using only two legs for walking) and having the capability to use tools have long been considered characteristic features that differentiate human beings from animals. Being able to walk upright freed up human hands, allowing us to reach, grasp, carry food, make and use tools, which greatly increased the survivability of our ancestors. Hand actions not only involve muscles and joints to execute actions but also require computations in the brain to analyze the visual environment and select the appropriate action, as well as formulate the action before execution and correct it in real-time during execution. Here, we review the behavioral and brain imaging research of human hand actions from a perspective of cognitive neuroscience. The review includes the research contents and methods of visually-guided action, existing theories, current debates, new evidence of existing theories, and the applications of action research in robotics and artificial intelligence.

Interleukin-17A Promotes Aortic Endothelial Cell Activation via Transcriptionally and Post-translationally Activating p38 Mitogen-activated Protein Kinase (MAPK) Pathway.

Interleukin-17 (IL-17)-secreting T helper 17 cells were recently identified as a CD4(+) T helper subset and implicated in various inflammatory and autoimmune diseases. The issues of whether and by what mechanism hyperlipidemic stress induces IL-17A to activate aortic endothelial cells (ECs) and enhance monocyte adhesion remained largely unknown. Using biochemical, immunological, microarray, experimental data mining analysis, and pathological approaches focused on primary human and mouse aortic ECs (HAECs and MAECs) and our newly generated apolipoprotein E (ApoE)(-/-)/IL-17A(-/-) mice, we report the following new findings. 1) The hyperlipidemia stimulus oxidized low density lipoprotein up-regulated IL-17 receptor(s) in HAECs and MAECs. 2) IL-17A activated HAECs and increased human monocyte adhesion in vitro. 3) A deficiency of IL-17A reduced leukocyte adhesion to endothelium in vivo. 3) IL-17A activated HAECs and MAECs via up-regulation of proinflammatory cytokines IL-6, granulocyte-macrophage colony-stimulating factor (GM-CSF), chemokine CXC motif ligand 1 (CXCL1), and CXCL2. 4) IL-17A activated ECs specifically via the p38 mitogen-activated protein kinases (MAPK) pathway; the inhibition of p38 MAPK in ECs attenuated IL-17A-mediated activation by ameliorating the expression of the aforementioned proinflammatory cytokines, chemokines, and EC adhesion molecules including intercellular adhesion molecule 1. Taken together, our results demonstrate for the first time that IL-17A activates aortic ECs specifically via p38 MAPK pathway.

Metabolic profile of salidroside in rats using high-performance liquid chromatography combined with Fourier transform ion cyclotron resonance mass spectrometry.

A high-performance liquid chromatography coupled to Fourier transform ion cyclotron resonance mass spectrometry (HPLC-FT-ICR MS) method was developed to study the in vivo metabolism of salidroside for the first time. Plasma, urine, bile, and feces samples were collected from male rats after a single intragastric gavage of salidroside at a dose of 50 mg/kg. Besides the parent drug, a total of seven metabolites (three phase I and four phase II metabolites) were detected and tentatively identified by comparing their mass spectrometry profiles with those of salidroside. Results indicated that metabolic pathways of salidroside in male rats included hydroxylation, dehydrogenation, glucuronidation, and sulfate conjugation. Among them, glucuronidation and sulfate conjugation were the major metabolic reactions. And most important, the detection of the sulfation metabolite of p-tyrosol provides a clue for whether the deglycosylation of salidroside occurs in vivo after intragastric gavage. In summary, results obtained in this study may contribute to the better understanding of the safety and mechanism of action of salidroside.

An Improved Zero Potential Circuit for Readout of a Two-Dimensional Resistive Sensor Array.

With one operational amplifier (op-amp) in negative feedback, the traditional zero potential circuit could access one element in the two-dimensional (2-D) resistive sensor array with the shared row-column fashion but it suffered from the crosstalk problem for the non-scanned elements' bypass currents, which were injected into array's non-scanned electrodes from zero potential. Firstly, for suppressing the crosstalk problem, we designed a novel improved zero potential circuit with one more op-amp in negative feedback to sample the total bypass current and calculate the precision resistance of the element being tested (EBT) with it. The improved setting non-scanned-electrode zero potential circuit (S-NSE-ZPC) was given as an example for analyzing and verifying the performance of the improved zero potential circuit. Secondly, in the S-NSE-ZPC and the improved S-NSE-ZPC, the effects of different parameters of the resistive sensor arrays and their readout circuits on the EBT's measurement accuracy were simulated with the NI Multisim 12. Thirdly, part features of the improved circuit were verified with the experiments of a prototype circuit. Followed, the results were discussed and the conclusions were given. The experiment results show that the improved circuit, though it requires one more op-amp, one more resistor and one more sampling channel, can access the EBT in the 2-D resistive sensor array more accurately.

NEDD8 ultimate buster-1 long (NUB1L) protein promotes transfer of NEDD8 to proteasome for degradation through the P97UFD1/NPL4 complex.

The NEDD8 protein and neddylation levels in cells are modulated by NUB1L or NUB1 through proteasomal degradation, but the underlying molecular mechanism is not well understood. Here, we report that NUB1L down-regulated the protein levels of NEDD8 and neddylation through specifically recognizing NEDD8 and P97/VCP. NUB1L directly interacted with NEDD8, but not with ubiquitin, on the key residue Asn-51 of NEDD8 and with P97/VCP on its positively charged VCP binding motif. In coordination with the P97-UFD1-NPL4 complex (P97(UFD1/NPL4)), NUB1L promotes transfer of NEDD8 to proteasome for degradation. This mechanism is also exemplified by the canonical neddylation of cullin 1 for SCF (SKP1-cullin1-F-box) ubiquitin E3 ligases that is exquisitely regulated by the turnover of NEDD8.

Discovery of a new sesquiterpenoid from Phellinus ignarius with antiviral activity against influenza virus.

Seven natural products, including one new sesquiterpenoid (eudesm-1ß, 6α, 11-triol, compound 1), one ergosta -4, 6, 8(14), 22-tetraen-3-one (compound 2), four polyphenols (compounds 3, 4, 5, 6), and one pyrone (3-hydroxy-2-methyl-4-pyrone, compound 7) were isolated from cultures of Phellinus ignarius by column chromatography. The detailed structure of compound 1 was determined using a combination of one- and two-dimensional nuclear magnetic resonance, mass spectrometry and infrared spectroscopy. The antiviral activity of these compounds against H5N1 influenza A virus was investigated using an MTT colorimetric assay system in Madin-Darby canine kidney cells. The results indicate that compound 1 possesses significant ability to inhibit influenza virus. The 50 % effective concentration was 0.14 ± 0.04 µM. Molecular modeling further suggested that the anti-influenza virus activity of this compound was partially attributed to the interactions of hydroxyl groups with an amino acid residue (Asn 170) of neuraminidase (NA) at the binding site. Moreover, the results of enzyme inhibition assays indicated that 50 % inhibition of NA was achieved by compound 1 at a concentration of 0.657 ± 0.325 mg/mL, which suggested that compound 1 is likely to interact with the NA enzyme.

Self-amplifying autocrine actions of BDNF in axon development.

A critical step in neuronal development is the formation of axon/dendrite polarity, a process involving symmetry breaking in the newborn neuron. Local self-amplifying processes could enhance and stabilize the initial asymmetry in the distribution of axon/dendrite determinants, but the identity of these processes remains elusive. We here report that BDNF, a secreted neurotrophin essential for the survival and differentiation of many neuronal populations, serves as a self-amplifying autocrine factor in promoting axon formation in embryonic hippocampal neurons by triggering two nested positive-feedback mechanisms. First, BDNF elevates cytoplasmic cAMP and protein kinase A activity, which triggers further secretion of BDNF and membrane insertion of its receptor TrkB. Second, BDNF/TrkB signaling activates PI3-kinase that promotes anterograde transport of TrkB in the putative axon, further enhancing local BDNF/TrkB signaling. Together, these self-amplifying BDNF actions ensure stable elevation of local cAMP/protein kinase A activity that is critical for axon differentiation and growth.

Two new indole-diterpenoids from the fungus Penicilliumcrustosum YN-HT-15.

Two new indole-diterpenoids named penijanthine B and penitrem H were isolated from the metabolites of the fungus Penicilliumcrustosum YN-HT-15, which was isolated from the red soil of Yunnan Province of China. The structures were determined on spectroscopic analyses and CD spectra.

[Short-term memory characteristics of vibration intensity tactile perception on human wrist].

In this study, a recall experiment and a recognition experiment were designed to assess the human wrist's short-term memory characteristics of tactile perception on vibration intensity, by using a novel homemade vibrotactile display device based on the spatiotemporal combination vibration of multiple micro vibration motors as a test device. Based on the obtained experimental data, the short-term memory span, recognition accuracy and reaction time of vibration intensity were analyzed. From the experimental results, some important conclusions can be made: (1) The average short-term memory span of tactile perception on vibration intensity is 3 ± 1 items; (2) The greater difference between two adjacent discrete intensities of vibrotactile stimulation is defined, the better average short-term memory span human wrist gets; (3) There is an obvious difference of the average short-term memory span on vibration intensity between the male and female; (4) The mechanism of information extraction in short-term memory of vibrotactile display is to traverse the scanning process by comparison; (5) The recognition accuracy and reaction time performance of vibrotactile display compares unfavourably with that of visual and auditory. The results from this study are important for designing vibrotactile display coding scheme.

Changes in posterior corneal elevation after small incision lenticule extraction for different myopic diopters.

AIM: To study the changes and effect factors of posterior corneal surface after small incision lenticule extraction (SMILE) with different myopic diopters. METHODS: Ninety eyes of 90 patients who underwent SMILE were included in this retrospective study. Patients were allocated into three groups based on the preoperative spherical equivalent (SE): low myopia (SE≥-3.00 D), moderate myopia (-3.00 D>SE>-6.00 D) and high myopia (SE≤-6.00 D). Posterior corneal surfaces were measured by a Scheimpflug camera preoperatively and different postoperative times (1wk, 1, 3, 6mo, and 1y). Posterior mean elevation (PME) at 25 predetermined points of 3 concentric circles (2-, 4-, and 6-mm diameter) above the best fit sphere was analyzed. RESULTS: All surgeries were completed uneventfully and no ectasia was found through the observation. The difference of myopia group was significant at the 2-mm ring at 1 and 3mo postoperatively (1mo: P=0.017; 3mo: P=0.018). The effect of time on ΔPME was statistically significant (2-mm ring: P=0.001; 4-mm ring: P<0.001; 6-mm ring: P<0.001). The effect of different corneal locations on ΔPME was significant except 1wk postoperatively (1mo: P=0.000; 3mo: P=0.000; 6mo: P=0.001; 1y: P=0.001). Posterior corneal stability was linearly correlated with SE, central corneal thickness, ablation depth, residual bed thickness, percent ablation depth and percent stromal bed thickness. CONCLUSION: The posterior corneal surface changes dynamically after SMILE. No protrusion is observed on the posterior corneal surface in patients with different degrees of myopia within one year after surgery. SMILE has good stability, accuracy, safety and predictability.

Length of the active-site crossover loop defines the substrate specificity of ubiquitin C-terminal hydrolases for ubiquitin chains.

UCHs [Ub (ubiquitin) C-terminal hydrolases] are a family of deubiquitinating enzymes that are often thought to only remove small C-terminal peptide tails from Ub adducts. Among the four UCHs identified to date, neither UCH-L3 nor UCH-L1 can catalyse the hydrolysis of isopeptide Ub chains, but UCH-L5 can when it is present in the PA700 complex of the proteasome. In the present paper, we report that the UCH domain of UCH-L5, different from UCH-L1 and UCH-L3, by itself can process the K48-diUb (Lys48-linked di-ubiquitin) substrate by cleaving the isopeptide bond between two Ub units. The catalytic specificity of the four UCHs is dependent on the length of the active-site crossover loop. The UCH domain with a long crossover loop (usually >14 residues), such as that of UCH-L5 or BAP1 [BRCA1 (breast cancer early-onset 1)-associated protein 1], is able to cleave both small and large Ub derivatives, whereas the one with a short loop can only process small Ub derivatives. We also found that elongation of the crossover loop enables UCH-L1 to have isopeptidase activity for K48-diUb in a length-dependent manner. Thus the loop length of UCHs defines their substrate specificity for diUb chains, suggesting that the chain flexibility of the crossover loop plays an important role in determining its catalytic activity and substrate specificity for cleaving isopeptide Ub chains.

Beneficial Root-Associated Microbiome during Drought and Flooding Stress in Plants.

Crop productivity is seriously threatened by the rise in the frequency and severity of drought and flood events around the world. Reduced drought and flooding stress in vulnerable species and ecosystems depends on our ability to comprehend how drought and flooding affect plant physiology and plant-associated microbes. Involvement of both abscisic acid ABA-dependent and ABA-independent pathways has been noted during drought. Hypoxic conditions impede hydraulic conductance, nutrient uptake and plant growth and development, as well as root aerobic respiration. The root microbiome, which works with the roots during drought and flood, is made up of plant growth-promoting rhizosphere, endophytes and mycorrhizas. A large number of phytohormones, primarily auxins, cytokinin and ethylene, as well as enzymes like 1-Aminocyclopropane-1-Carboxylate deaminase (ACC deaminase) and metabolites like exopolysaccharides are produced by rhizospheric microbes. These phytohormones, enzymes and metabolites have role in the induction of systemic drought tolerance in plants. Under hypoxia, anaerobic microbes with the potential to harm the plant due to their pathogenic behavior or soil denitrification ability are more likely to be present in the rhizosphere and roots. This review concentrates on the primary mechanisms of plant-microbe interactions under drought and flood stress as well as the importance of flood and drought-tolerant microbes in maintaining and increasing crop plant productivity under stress.

Drought Stress Decreases Morphophysiological Characteristics of Pongamia pinnata (L.) Pierre a Biodiesel Tree.

<b>Background and Objective:</b> Drought stress is a condition of water shortage in plants. One tree species targeted for planting on marginal lands is <i>Pongamia pinnata</i> which produces oil for biodiesel feedstock. The aims of the present study were to evaluate the morphophysiological response of <i>Pongamia pinnata</i> and its resistance mechanism under drought stress at the seedling stage. <b>Materials and Methods:</b> Three months old Pongamia seedlings were given 4 treatments of watering intervals, namely every day (control) and every 7th, 14th and 21st day at field capacity indicating no stress, moderate stress, high stress and very high stress, respectively. Measurement of growth parameters was carried out every month for 4 months. Data were analyzed using one-way analysis of variance at a significance level of 5%. <b>Results:</b> Very high drought stress reduced plant survival to 60% at 3 MAP (month after planting) and dead at 4 MAP. Both moderate and high drought stresses slow down height growth. Both specific leaf area and leaf area ratio decreased dramatically by 45.7 and 63.74%, respectively at a very high drought stress treatment at 3 MAP. Root length decreased slightly by 18.40% at very high drought stress. Total plant dry weight decreased by 15.9 and 46.4% by high and very high drought stress respectively. Leaf pigment content decreased sharply to very high drought stress. <b>Conclusion:</b> Pongamia seedlings survived under moderate and high drought stress. This was achieved by reducing plant height, leaf area, dry weights and pigment content. The resistance mechanism was drought avoidance, achieved by dropping leaves and maintaining root growth.

Occurrence and carcinogenic potential of airborne PBDD/Fs and PCDD/Fs around a large-scale municipal solid waste incinerator: A long-term passive air sampling study.

Municipal solid waste incinerator (MSWI) not only is deemed one of the uppermost sources of polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs), but also produces substantial amount of polybrominated dibenzo-p-dioxins/furans (PBDD/Fs) owing to the existence of brominated flame retardants (BFRs) in the waste. So far, however, PBDD/Fs in the vicinal environments of MSWI and their associated risks remain rarely studied. Based on a one-year passive air sampling (PAS) scheme, we investigated airborne PBDD/Fs and PCDD/Fs around a large-scale MSWI that has been operated for multi-years. Both the concentrations of PBDD/Fs and PCDD/Fs showed spatially decreasing trends with the distance away from the MSWI, confirming the influence of the MSWI on the dioxin levels in its ambient air. But its influence on PBDD/Fs was less because PBDD/Fs exhibit lower volatility and therefore lower gaseous concentrations than PCDD/Fs. Compared to the existing global data of airborne PCDD/Fs and PBDD/Fs, our data of the MSWI vicinity were at medium levels, despite PAS samples only represent the concentrations of gaseous dioxins in theory. The seasonal data suggest that meteorological conditions exerted apparent influences over the concentrations and sources of airborne dioxins around the MSWI. As for PCDD/Fs, the MSWI was diagnosed as their uppermost source, followed by local traffic and volatilization/deposition. Whereas the top three PBDD/F sources were related to PBDEs, bromophenol/bromobenzene, and traffic vehicles, respectively. The bioassay-derived TEQs based on the aryl hydrocarbon receptor activation of airborne dioxins around the MSWI were one or two orders of magnitudes higher than their concentration-based TEQs, and the corresponding carcinogenic risks at some MSWI-vicinal sites exceeded the acceptable threshold proposed by the U. S. EPA (10-6 âˆ¼ 10-4) and deserve continuous attention.

Organophosphate esters (OPEs) in a heavily polluted river in South China: Occurrence, spatiotemporal trends, sources, and phase distribution.

In the past decade, organophosphate esters (OPEs) undergo rapid increase in production and use. Meanwhile, owing to their additive property, OPEs exhibit liability to escape from related products and therefore ubiquity in various environments. Moreover, numerous researches verify their bioavailability and negative effects on biota and human, hence their occurrence and associated risks have caught much concern, particularly those in aquatic systems. So far, however, OPEs in water are generally investigated as a whole, their phase distribution and behavior in waterbodies are incompletely characterized. We examined 25 OPEs in water (including dissolved and particulate phases), sediment, and sediment core samples from the Lian River, which flows through the Guiyu e-waste recycling zone and Shantou specific economic zone in South China. Compared to most global waterbodies, the Lian River showed high or ultrahigh OPE levels in both water and sediments, particularly in the reaches surrounded by e-waste recycling and plastic-related industries, which were the top two greatest OPE sources. Non-industrial and agriculture-related anthropogenic activities also contributed OPEs. Sediment core data suggested that OPEs have been present in waters in Guiyu since the 1960s and showed a temporal trend consistent with the local waste-recycling business. The phase distribution of OPEs in the Lian River was significantly correlated with their hydrophobicity and solubility. Owing to their wide range of physicochemical properties, OPE congeners showed significant percentage differences in the Lian River water and sediments. Generally, OPEs in water reflect their dynamic real-time inputs, while those in sediment signify their accumulative deposition, which is another cause of their phase distribution disparities in the Lian River. The physicochemical parameters of OPEs first imposed negative and then positive influences on their dissolved phase-sediment distribution, indicating the involvement of both the adsorption of dissolved OPEs and the deposition of particle-bound OPEs.