14 research outputs found

    Polychlorinated biphenyls (PCBs) and hexachlorobenzene (HCB) in the equatorial Indian Ocean: Temporal trend, continental outflow and air-water exchange

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    Nineteen pairs of air and seawater samples collected from the equatorial Indian Ocean onboard the Shiyan I from 4/2011 to 5/2011 were analyzed for PCBs and HCB. Gaseous concentrations of Sigma(ICES)PCBs (ICES: International Council for the Exploration of the Seas) and HCB were lower than previous data over the study area. Air samples collected near the coast had higher levels of PCBs relative to those collected in the open ocean, which may be influenced by proximity to source regions and air mass origins. Dissolved concentrations of Sigma(ICES)PCBs and HCB were 1.4-14 pg L-1 and 0.94-13 pg L-1, with the highest concentrations in the sample collected from Strait of Malacca. Fugacity fractions suggest volatilization of PCBs and HCB from the seawater to air during the cruise, with fluxes of 0.45-34 ng m(-2) d(-1) and 0.36-18 ng m(-2) d(-1), respectively. (c) 2014 Elsevier Ltd. All rights reserved.Nineteen pairs of air and seawater samples collected from the equatorial Indian Ocean onboard the Shiyan I from 4/2011 to 5/2011 were analyzed for PCBs and HCB. Gaseous concentrations of Sigma(ICES)PCBs (ICES: International Council for the Exploration of the Seas) and HCB were lower than previous data over the study area. Air samples collected near the coast had higher levels of PCBs relative to those collected in the open ocean, which may be influenced by proximity to source regions and air mass origins. Dissolved concentrations of Sigma(ICES)PCBs and HCB were 1.4-14 pg L-1 and 0.94-13 pg L-1, with the highest concentrations in the sample collected from Strait of Malacca. Fugacity fractions suggest volatilization of PCBs and HCB from the seawater to air during the cruise, with fluxes of 0.45-34 ng m(-2) d(-1) and 0.36-18 ng m(-2) d(-1), respectively. (c) 2014 Elsevier Ltd. All rights reserved

    Investigating Effects of Heterogeneity and Fracture Distribution on Two-Phase Flow in Fractured Reservoir with adaptive time strategy

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    Modeling of fluid flow in porous media is a pillar in geoscience applications. Previous studies have revealed that heterogeneity and fracture distribution have considerable influence on fluid flow. In this work, a numerical investigation of two-phase flow in heterogeneous fractured reservoir is presented. First, the discrete fracture model is implemented based on a hybrid-dimensional modeling approach, and an equivalent continuum approach is integrated in the model to reduce computational cost. A multilevel adaptive strategy is devised to improve the numerical robustness and efficiency. It allows up to 4-levels adaption, where the adaptive factors can be modified flexibly. Then, numerical tests are conducted to verify the the proposed method and to evaluate its performance. Different adaptive strategies with 3-levels, 4-levels and fixed time schemes are analyzed to evaluate the computational cost and convergence history. These evaluations demonstrate the merits of this method compared to the classical method. Later, the heterogeneity in permeability field, as well as initial saturation, is modeled in a layer model, where the effect of layer angle and permeability on fluid flow is investigated. A porous medium containing multiple length fractures with different distributions is simulated. The fine-scale fractures are upscaled based on the equivalent approach, while the large-scale fractures are retained. The conductivity of the rock matrix is enhanced by the upscaled fine-scale fractures. The difference of hydraulic property between homogeneous and heterogeneous situations is analyzed. It reveals that the heterogeneity may influence fluid flow and production, while these impacts are also related to fracture distribution and permeability.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Delft Institute of Applied Mathematic

    Global effects of subchronic treatment of microcystin-LR on rat splenetic protein levels

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    Microcystin-LR (MCLR), released by toxic cyanobacterial blooms, has received worldwide concerns in the past decades for its hepatotoxicity. Recent studies show that microcystins (MCs) can be accumulated in immune organs and exert notable immunotoxicity. In order to better understand cellular responses in immune tissues disrupted by MCLR treatment, this work mainly focuses on the spleen impairments of rats. After a subchronic 50 d exposure (1 or 10 mu g/kg body weight per day), spleen index, MCLR accumulation, histological change and plasma lysozyme activity were detected in MCLR-treated rat. Results indicated that prolonged exposure of MCLR led to toxin accumulation and caused severe damage in spleen of rats, and eventually impaired the immune functions. To further our understanding of the toxic effects of MCLR on the spleen and the mechanisms behind it, a proteomic analysis was performed to determine the global effects of MCLR on splenetic protein levels. In total, 48 proteins were identified and showed a significant increase or decrease in abundance compared to the control after MCLR exposure. These proteins are mainly involved in immune response, oxidative stress, energetic metabolism and the cytoskeleton assembly, indicating that MCLR exerts complex toxic effects in rat spleen and jointly results in immunotoxicity. (C) 2012 Elsevier B.V. All rights reserved.Microcystin-LR (MCLR), released by toxic cyanobacterial blooms, has received worldwide concerns in the past decades for its hepatotoxicity. Recent studies show that microcystins (MCs) can be accumulated in immune organs and exert notable immunotoxicity. In order to better understand cellular responses in immune tissues disrupted by MCLR treatment, this work mainly focuses on the spleen impairments of rats. After a subchronic 50 d exposure (1 or 10 mu g/kg body weight per day), spleen index, MCLR accumulation, histological change and plasma lysozyme activity were detected in MCLR-treated rat. Results indicated that prolonged exposure of MCLR led to toxin accumulation and caused severe damage in spleen of rats, and eventually impaired the immune functions. To further our understanding of the toxic effects of MCLR on the spleen and the mechanisms behind it, a proteomic analysis was performed to determine the global effects of MCLR on splenetic protein levels. In total, 48 proteins were identified and showed a significant increase or decrease in abundance compared to the control after MCLR exposure. These proteins are mainly involved in immune response, oxidative stress, energetic metabolism and the cytoskeleton assembly, indicating that MCLR exerts complex toxic effects in rat spleen and jointly results in immunotoxicity. (C) 2012 Elsevier B.V. All rights reserved

    Eichhornia crassipes Cleans Wetlands by Enhancing the Nitrogen Removal and Modulating Denitrifying Bacteria Community

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    The role of floating macrophytes on modulating the microbial nitrogen removal is not well understood. In this study, the cultivation of Eichhornia crassipes in eutrophic water may affect the nitrogen (N) fate by modulating the denitrifying bacteria diversity and abundance. The gaseous N losses via denitrification were estimated by 15N stable isotope tracing and the diversity and abundance of denitrifying genes (nirS, nirK, and nosZ) were investigated by molecular tools. The denaturing gradient gel electrophoresis (DGGE) profiles showed that the diversity of denitrifying genes in the treatments with E. crassipes was significantly higher than that in the treatment without E. crassipes. The real-time PCR (qPCR) results showed the trend of denitrifier abundance in the entire system was in the order of N-ER (nitrate with just root of E. crassipes) and A-ER (ammonia with just root of E. crassipes)>N-R (nitrate with E. crassipes) and A-R (ammonia with E. crassipes)>N-W (nitrate without plant) and A-W (ammonia without plant). The gaseous 15N losses via denitrification were significantly and positively related to the abundance of nirK, nirS, and nosZ genes. The results indicated that cultivation of E. crassipes in eutrophic water could increase the diversity and abundance of denitrifying bacteria, resulting in more N being removed as gases via denitrification.The role of floating macrophytes on modulating the microbial nitrogen removal is not well understood. In this study, the cultivation of Eichhornia crassipes in eutrophic water may affect the nitrogen (N) fate by modulating the denitrifying bacteria diversity and abundance. The gaseous N losses via denitrification were estimated by 15N stable isotope tracing and the diversity and abundance of denitrifying genes (nirS, nirK, and nosZ) were investigated by molecular tools. The denaturing gradient gel electrophoresis (DGGE) profiles showed that the diversity of denitrifying genes in the treatments with E. crassipes was significantly higher than that in the treatment without E. crassipes. The real-time PCR (qPCR) results showed the trend of denitrifier abundance in the entire system was in the order of N-ER (nitrate with just root of E. crassipes) and A-ER (ammonia with just root of E. crassipes)>N-R (nitrate with E. crassipes) and A-R (ammonia with E. crassipes)>N-W (nitrate without plant) and A-W (ammonia without plant). The gaseous 15N losses via denitrification were significantly and positively related to the abundance of nirK, nirS, and nosZ genes. The results indicated that cultivation of E. crassipes in eutrophic water could increase the diversity and abundance of denitrifying bacteria, resulting in more N being removed as gases via denitrification

    Effects of risperidone and haloperidol on superoxide dismutase and nitric oxide in schizophrenia

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    Oxidative stress may be involved in the pathophysiology of schizophrenia. No double-blind study has compared the effects of typical and atypical antipsychotics on both antioxidant enzyme activity and nitric oxide (NO) levels in schizophrenic patients. Seventy-eight inpatients with chronic schizophrenia were randomly assigned to 12 weeks of treatment with 6 mg/day of risperidone or 20 mg/day of haloperidol using a double-blind design. Clinical efficacy was determined using the Positive and Negative Syndrome Scale. Blood superoxide dismutase (SOD) and plasma NO levels were measured in patients and 30 normal controls. Our results showed that following a 2-week washout period, levels of SOD and NO were significantly increased in patients with schizophrenia compared to normal controls. Both risperidone and haloperidol equivalently reduced the elevated blood SOD levels in schizophrenia, but neither medication reduced the elevated plasma NO levels in schizophrenia. Low blood SOD levels at baseline predicted greater symptom improvement during treatment, and greater change in SOD was correlated with greater symptom improvement. These results suggest that both typical and atypical antipsychotic drugs may at least partially normalize abnormal free radical metabolism in schizophrenia, and some free radical parameters at baseline may predict antipsychotic responses of schizophrenic patients. (C) 2011 Elsevier Ltd. All rights reserved

    An Engineered Arginase FC Protein Inhibits Tumor Growth In Vitro and In Vivo

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    Arginine is a semiessential amino acid required for the growth of melanoma and hepatocellular carcinoma, and the enzymatic removal of arginine by pegylated arginine deiminase (ADI) or arginase is being tested clinically. Here, we report a genetically engineered arginase FC fusion protein exhibiting a prolonged half-life and enhanced efficacy. The use of this enzyme to treat different tumor lines both inhibited cell proliferation and impaired cellular migration in vitro and in vivo. Our data reinforce the hypothesis that nutritional depletion is a key strategy for cancer treatment

    Exploring the Polyadenylated RNA Virome of Sweet Potato through High-Throughput Sequencing

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    Background: Viral diseases are the second most significant biotic stress for sweet potato, with yield losses reaching 20% to 40%. Over 30 viruses have been reported to infect sweet potato around the world, and 11 of these have been detected in China. Most of these viruses were detected by traditional detection approaches that show disadvantages in detection throughput. Next-generation sequencing technology provides a novel, high sensitive method for virus detection and diagnosis. Methodology/Principal Findings: We report the polyadenylated RNA virome of three sweet potato cultivars using a high throughput RNA sequencing approach. Transcripts of 15 different viruses were detected, 11 of which were detected in cultivar Xushu18, whilst 11 and 4 viruses were detected in Guangshu 87 and Jingshu 6, respectively. Four were detected in sweet potato for the first time, and 4 were found for the first time in China. The most prevalent virus was SPFMV, which constituted 88% of the total viral sequence reads. Virus transcripts with extremely low expression levels were also detected, such as transcripts of SPLCV, CMV and CymMV. Digital gene expression (DGE) and reverse transcription polymerase chain reaction (RT-PCR) analyses showed that the highest viral transcript expression levels were found in fibrous and tuberous roots, which suggest that these tissues should be optimum samples for virus detection. Conclusions/Significance: A total of 15 viruses were presumed to present in three sweet potato cultivars growing in China. This is the first insight into the sweet potato polyadenylated RNA virome. These results can serve as a basis for further work to investigate whether some of the 'new' viruses infecting sweet potato are pathogenic

    Moderate Drought Stress Affected Root Growth and Grain Yield in Old, Modern and Newly Released Cultivars of Winter Wheat

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    To determine root growth and grain yield of winter wheat (Triticum aestivum L) under moderate drought stress, a nursery experiment and a field trial were conducted with or without water stress using three representative cultivars released in different years: CW134 (old landrace), CH58 (modern cultivar) and CH1 (new release). In the nursery experiment, plants were grown in soil-filled rhizoboxes under moderate drought (MD, 55% of field capacity) or well-watered (WW, 85% of field capacity) conditions. In the field trial, plots were either rainfed (moderate drought stress) or irrigated with 30 mm of water at each of stem elongation, booting and anthesis stages (irrigated). Compared to drought stress, grain yields increased under sufficient water supply in all cultivars, particular the newly released cultivar CH1 with 70% increase in the nursery and 23% in the field. When well-watered (nursery) or irrigated (field), CH1 had the highest grain yields compared to the other two cultivars, but produced similar yield to the modern cultivar (CH58) under water-stressed (nursery) or rainfed (field) conditions. When exposed to drought stress, CW134 had the highest topsoil root dry mass in topsoil but lowest in subsoil among the cultivars at stem elongation, anthesis, and maturity, respectively; while CH1 had the lowest topsoil and highest subsoil root dry mass at respective sampling times. Topsoil root mass and root length density were negatively correlated with grain yield for the two water treatments in nursery experiment. When water was limited, subsoil root mass was positively correlated with thousand kernel weight (TKW). In the field trial, CH1 and CH58 used less water during vegetative growth than CW134, but after anthesis stage, CH1 used more water than the other two cultivars, especially in the soil profile below 100 cm, which was associated with the increased TKW. This study demonstrated that greater root mass and root length density in subsoil layers, with enhanced access to subsoil water after anthesis, contribute to high grain yield when soil water is scarce

    Tunable diode laser absorption spectroscopy measurements of high-pressure ammonium dinitramide combustion

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    The working processes of the ADN-based liquid thruster are complex, utilizing catalytic decomposition in a catalyst bed and high-pressure combustion in the combustion chamber. The present study examines the experimental performance of high-pressure combustion in an ADN-based liquid thruster. Using the Tunable Diode Laser Absorption Spectroscopy (TDLAS) method, flow parameters such as gas temperature and the characteristic species concentration of CO in the combustion chamber were measured instantaneously under the atmospheric environment. The effects of propellant inlet pressure and the catalyst bed preheated temperature on the combustion process were evaluated. It was found that both an increase in the propellant inlet pressure and an increase in the catalyst bed preheated temperature led to an increase in the gas temperature and a decrease of the CO mole fraction in the combustion chamber. In a hot fire test in the vacuum chamber, the performance of the model thruster under steady operation was tested. The results showed that with the increase of propellant inlet pressure, the combustion chamber pressure and the combustion chamber wall temperature also increase. However, although the increase of the catalyst bed preheated temperature also led to the increase of the combustion chamber wall temperature, the combustion chamber pressure remained nearly constant. These results provide a better understanding of the mechanisms of high-pressure combustion with ADN-based liquid propellants, which is beneficial to the development of green aerospace propulsion techniques. (C) 2015 Elsevier Masson SAS. All rights reserved. The working processes of the ADN-based liquid thruster are complex, utilizing catalytic decomposition in a catalyst bed and high-pressure combustion in the combustion chamber. The present study examines the experimental performance of high-pressure combustion in an ADN-based liquid thruster. Using the Tunable Diode Laser Absorption Spectroscopy (TDLAS) method, flow parameters such as gas temperature and the characteristic species concentration of CO in the combustion chamber were measured instantaneously under the atmospheric environment. The effects of propellant inlet pressure and the catalyst bed preheated temperature on the combustion process were evaluated. It was found that both an increase in the propellant inlet pressure and an increase in the catalyst bed preheated temperature led to an increase in the gas temperature and a decrease of the CO mole fraction in the combustion chamber. In a hot fire test in the vacuum chamber, the performance of the model thruster under steady operation was tested. The results showed that with the increase of propellant inlet pressure, the combustion chamber pressure and the combustion chamber wall temperature also increase. However, although the increase of the catalyst bed preheated temperature also led to the increase of the combustion chamber wall temperature, the combustion chamber pressure remained nearly constant. These results provide a better understanding of the mechanisms of high-pressure combustion with ADN-based liquid propellants, which is beneficial to the development of green aerospace propulsion techniques. (C) 2015 Elsevier Masson SAS. All rights reserved.</p

    Abnormal baseline brain activity in bipolar depression: A resting state functional magnetic resonance imaging study

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    We examined resting state brain activity in the depressive phase of bipolar disorder (BD) by measuring the amplitude of low-frequency fluctuations (ALFF) in the functional magnetic resonance imaging (fMRI) signal. Unlike functional connectivity, the ALFF approach reflects local properties in specific regions and provides direct information about impaired foci. Groups of 26 patients with BD depression and 26 gender-, age-, and education-matched healthy subjects participated in fMRI scans. We examined group differences in ALFF findings as well as correlations between clinical measurements and ALFF in the regions showing significant group differences. Our results showed that patients with BD depression had significantly increased ALFF in the left insula, the right caudate nucleus, the temporal gyrus, the bilateral inferior frontal gyrus, and the posterior lobe of the cerebellum. They also had decreased ALFF in the left postcentral gyrus, the left parahippocampal gyrus, and the cerebellum. Moderate negative correlations were found between the Hamilton Depression Rating Scale score and ALFF in the left insular cortex in the patient group. These results support a model of BD that involves dysfunction in the prefrontal-limbic networks and associated striatal systems. We also demonstrated the feasibility of ALFF as a technique to investigate persistent cerebral dysfunction in BD. (C) 2012 Elsevier Ireland Ltd. All rights reserved
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