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Subacute static magnetic field exposure in rat induces a pseudoanemia status with increase in MCT4 and Glut4 proteins in glycolytic muscle Full text
2016
Elferchichi, Miryam | Mercier, Jacques | Ammari, Mohamed | Belguith, Hatem | Abdelmelek, Hafedh | Sakly, Mohsen | Vajradevi,
The purpose of this study was to investigate the effect of subacute exposure to static magnetic fields (SMF) on hematological and muscle biochemical parameters in rats. Male Wistar rats, daily exposed to SMF, were exposed to SMF (128 mT, 1 h/day) during 15 consecutive days. SMF-exposed rats showed a significant decrease in red blood cell (RBC) count, hemoglobin (Hb), and hematocrit (Ht) values compared to sham-exposed rats (p < 0.05). Concomitant decreases of plasma iron level against increase in transferrin amount were also observed after SMF exposure (p < 0.0.05). In postprandial condition, SMF-exposed rats presented higher plasma lactate (p < 0.01). Additionally, SMF exposure increased monocarboxylate transporters (MCT4) and glucose transporter 4 (Glut4)’s contents only in glycolytic muscle (p < 0.05). SMF exposure induced alteration of hematological parameters; importantly, we noticed a pseudoanemia status, which seems to affect tissue oxygen delivery. Additionally, SMF exposure seems to favor the extrusion of lactate from the cell to the blood compartment. Given that, these arguments advocate for an adaptive response to a hypoxia status following SMF exposure.
Show more [+] Less [-]Catalytic ozonation of sulfamethoxazole by composite iron-manganese silicate oxide: cooperation mechanism between adsorption and catalytic reaction Full text
2016
Gao, Guoying | Kang, Jing | Shen, Jimin | Chen, Zhonglin | Zhu, Wei
A systematic investigation of the cooperation mechanism between adsorption and catalytic reaction during the catalytic ozonation of sulfamethoxazole (SMX) by composite iron-manganese silicate oxide (FMSO) was carried out in this work. Results showed that the total organic carbon (TOC) removal increased significantly from 27 % (sole-ozonation) to 79.8 % (FMSO catalytic ozonation). The presence of FMSO in the ozonation process effectively enhanced the ozone utilization efficiency and accelerated the transformation of ozone into hydroxyl radicals. The latter result was verified by the indirect method, using NaHSO₃ as the reductor, and the direct electron spin resonance (ESR) determination technology. The adsorption of SMX on FMSO was minimal (1.8 %). However, ozone rapidly converted SMX into various intermediates, which was exhibited by the much higher adsorption affinity on the surface of FMSO than that of SMX. The accumulation of various intermediates on the FMSO surface also increased their contact probability with the ·OH radicals generated by the ozone decomposition. The continuous interaction of intermediates with ·OH radicals could further promote the benign cycling of the release of adsorption sites and the succeeding adsorption/decomposition of ozone and intermediates on FMSO. This could be another reason for the higher and faster TOC removal rate.
Show more [+] Less [-]Photocatalytic performance of electrospun CNT/TiO2 nanofibers in a simulated air purifier under visible light irradiation Full text
2016
Wongaree, Mathana | Chiarakorn, Siriluk | Chuangchote, Surawut | Sagawa, Takashi
The photocatalytic treatment of gaseous benzene under visible light irradiation was developed using electrospun carbon nanotube/titanium dioxide (CNT/TiO₂) nanofibers as visible light active photocatalysts. The CNT/TiO₂ nanofibers were fabricated by electrospinning CNT/poly(vinyl pyrrolidone) (PVP) solution followed by the removal of PVP by calcination at 450 °C. The molar ratio of CNT/TiO₂ was fixed at 0.05:1 by weight, and the quantity of CNT/TiO₂ loaded in PVP solution varied between 30 and 60 % wt. CNT/TiO₂ nanofibers have high specific surface area (116 m²/g), significantly higher than that of TiO₂ nanofibers (44 m²/g). The photocatalytic performance of the CNT/TiO₂ nanofibers was investigated by decolorization of 1 × 10⁻⁵ M methylene blue (MB) dye (in water solution) and degradation of 100 ppm gaseous benzene under visible light irradiation. The 50-CNT/TiO₂ nanofibers (calcined CNT/TiO₂ nanofibers fabricated from a spinning solution of 50 % wt CNT/TiO₂ based on PVP) had higher MB degradation efficiency (58 %) than did other CNT/TiO₂ nanofibers and pristine TiO₂ nanofibers (15 %) under visible light irradiation. The photocatalytic degradation of gaseous benzene under visible light irradiation on filters made of 50-CNT/TiO₂ nanofibers was carried out in a simulated air purifier system. Similar to MB results, the degradation efficiency of gaseous benzene by 50-CNT/TiO₂ nanofibers (52 %) was higher than by other CNT/TiO₂ nanofibers and pristine TiO₂ nanofibers (18 %). The synergistic effects of the larger surface area and lower band gap energy of CNT/TiO₂ nanofibers were presented as strong adsorption ability and greater visible light adsorption. The CNT/TiO₂ nanofiber prepared in this study has potential for use in air purifiers to improve air treatment efficiency with less energy.
Show more [+] Less [-]Degradation of monocrotophos by Starkeya novella YW6 isolated from paddy soil Full text
2016
Sun, Lina | Zhu, Shijun | Yang, Zhengzhong | Chen, Qing | Liu, Hongming | Zhang, Jun | Hu, Gang | Li, Shunpeng | Hong, Qing
A bacteria strain, YW6, capable of utilizing monocrotophos (MCP) as the sole carbon and nitrogen sources for growth was isolated from paddy soil and identified as Starkeya novella. Strain YW6 completely degraded 0.2 mM MCP within 36 h without any lag period. Addition of carbon source resulted in slowing down of the initial rate of degradation of MCP, while the presence of a more favorable source of nitrogen enhanced the degradation of MCP. In addition to the degradation of MCP, strain YW6 was also able to degrade a wide range of organophosphorus pesticides (OPs) containing P–O–C bond, but not dimethoate, which has P–S–C bond. A MCP degradation pathway was proposed on the basis of metabolite production patterns and identification of the metabolites. MCP is hydrolyzed at the P–O–C bond to form N-methylacetoacetamide and dimethyl phosphate; N-methylacetoacetamide is transformed to N-methyl-4-oxo-pentanamide, which was subsequently converted to 5-(methylamino)-5-oxo-pentanoic acid, and 5-(methylamino)-5-oxo-pentanoic acid is cleaved to glutaric acid and methylamine. These findings provide new insights into the microbial metabolism of MCP. To the best of our knowledge, this is the first report on the degradation of MCP by Starkeya bacteria.
Show more [+] Less [-]Effects of sediment dredging on nitrogen cycling in Lake Taihu, China: Insight from mass balance based on a 2-year field study Full text
2016
Yu, Juhua | Fan, Chengxin | Zhong, Jicheng | Zhang, Lu | Zhang, Lei | Wang, Changhui | Yao, Xiaolong
Sediment dredging can permanently remove pollutants from an aquatic ecosystem, which is considered an effective approach to aquatic ecosystem restoration. In this work, a 2-year field simulation test was carried out to investigate the effect of dredging on nitrogen cycling across the sediment-water interface (SWI) in Lake Taihu, China. The results showed that simulated dredging applied to an area rich in total organic carbon (TOC) and total nitrogen (TN) slightly reduced the NH₄ ⁺-N release from sediments while temporarily enhanced the NH₄ ⁺-N release in an area with lower TOC and/or TN (in the first 180 days), although the application had a limited effect on the fluxes of NO₂ ⁻-N and NO₃ ⁻-N in both areas. Further analysis indicated that dredging induced decreases in nitrification, denitrification, and anaerobic ammonium oxidation (anammox) in sediments, notably by 76.9, 49.0, and 89.9 %, respectively, in the TOC and/or TN-rich area. Therefore, dredging slowed down nitrogen cycling rates in sediments but did not increase N loading to overlying water. The main reason for the above phenomenon could be attributed to the removal of the surface sediments enriched with more TOC and/or TN (compared with the bottom sediments). Overall, to minimize internal N pollution, dredging may be more applicable to nutrient-rich sediments.
Show more [+] Less [-]Experimental and numerical characterization of floc morphology: role of changing hydraulic retention time under flocculation mechanisms Full text
2016
Nan, Jun | Yao, Meng | Chen, Ting | Wang, Zhenbei | Li, Qinggui | Zhan, Dan
The formation, breakage, and re-growth of flocs were investigated by using modified flocculation tests and numerical simulation to explore the evolution of floc morphology for different hydraulic retention times. The shorter the aggregation time was, the smaller the flocs produced for the same hydraulic conditions were. Another interesting discovery was that broken flocs that formed in shorter aggregation time had the capacity to completely recover, whereas those formed in a longer amount of time had rather worse reversibility of broken flocs. With the addition of the maximum motion step in the representative two-dimensional diffusion-limited aggregation (DLA) model, there was a transition for flocs from isotropic to anisotropic as the maximum motion step increased. The strength of flocs was mainly affected by the distribution of particles near the aggregated core rather than distant particles. A simplified breakage model, which found that broken flocs provided more chances for diffused particles to access the inner parts of flocs and to be uniformly packed around the aggregated core, was first proposed. Moreover, an important result showed that the floc fragments formed with a larger value of the maximum motion step had more growing sites than did those with a smaller msa value, which was a benefit of following the re-forming procedure.
Show more [+] Less [-]Monsoon-driven transport of atmospheric mercury to the South China Sea from the Chinese mainland and Southeast Asia—Observation of gaseous elemental mercury at a background station in South China Full text
2016
Liu, Ming | Chen, Laiguo | Xie, Donghai | Sun, Jiaren | He, Qiusheng | Cai, Limei | Gao, Zhiqiang | Zhang, Yiqiang
Concentrations of gaseous elemental mercury (GEM) were continuously monitored from May 2011 to May 2012 at the Wuzhishan State Atmosphere Background Monitoring Station (109°29′30.2″ E, 18°50′11.0″ N) located in Hainan Island. This station is an ideal site for monitoring long-range transport of atmospheric pollutants from mainland China and Southeast Asia to South China Sea. Annual average GEM concentration was 1.58 ± 0.71 ng m⁻³ during the monitoring period, which was close to background values in the Northern Hemisphere. GEM concentrations showed a clear seasonal variation with relatively higher levels in autumn (1.86 ± 0.55 ng m⁻³) and winter (1.80 ± 0.62 ng m⁻³) and lower levels in spring (1.16 ± 0.45 ng m⁻³) and summer (1.43 ± 0.46 ng m⁻³). Long-range atmospheric transport dominated by monsoons was a dominant factor influencing the seasonal variations of GEM. The GEM diel trends were related to the wind speed and long-range atmospheric mercury transport. We observed 30 pollution episodes throughout the monitoring period. The analysis of wind direction and backward trajectory suggested that elevated GEM concentrations at the monitoring site were primarily related to the outflows of atmospheric Hg from mainland China and the Indochina peninsula. The △GEM/△CO values also suggested that GEM was significantly affected by the long-range transport from the anthropogenic sources and biomass burning in Asia and Indochina peninsula.
Show more [+] Less [-]Biochemical biomarker responses to pollution in selected sentinel organisms across the Eastern Mediterranean and the Black Sea Full text
2016
Catherine, Tsangaris | Vanessa, Moschino | Evangelia, Strogyloudi | Valentina, Coatu | Andreja, Ramšak | Rana, Abu Alhaija | Susana, Carvalho | Serena, Felline | Alisa, Kosyan | Yiota, Lazarou | Ioannis, Hatzianestis | Andra, Oros | Daniela, Tiganus
Pollution effects were assessed by means of biochemical biomarkers (catalase, glutathione S-transferase and acetylcholinesterase activities, and metallothioneins content) in five species at selected coastal sites across the Eastern Mediterranean and the Black Sea. The mussel Mytilus galloprovincialis, a well-established sentinel species, was investigated in the Adriatic Sea, Aegean Sea, and Black Sea. The mussel Brachidontes pharaonis and the striped red mullet Mullus surmuletus were used in the Levantine Sea where M. galloprovincialis is not present. The white seabream Diplodus sargus sargus and the gastropod Rapana venosa were additionally sampled in the Adriatic and the Black Sea, respectively. Mussels showed catalase, glutathione S-transferase, and acetylcholinesterase responses to pollution in most geographical areas while the response of metallothioneins was restricted to a few sites. R. venosa showed marked responses of catalase and metallothioneins whereas both fish species did not generally exhibit variations in biomarker values among sites. The approach based on the reference deviation concept using the “Integrated Biological Responses version 2” index was useful for the interpretation of overall biomarker responses.
Show more [+] Less [-]Isolation, purification, and identification of antialgal substances in green alga Ulva prolifera for antialgal activity against the common harmful red tide microalgae Full text
2016
Sun, Ying-ying | Wang, Hui | Guo, Gan-lin | Pu, Yin-fang | Yan, Bin-lun | Wang, Chang-hai
Ten compounds (1~10) were successfully isolated from green algae Ulva prolifera through the combination of silica gel column chromatography, Sephadex LH-20 column chromatography and repeated preparative thin-layer chromatography. These ten compounds showed antialgal activity against red tide microalgae. Among them, compounds 3, 6, and 7 showed stronger antialgal activity against red tide microalgae. Furthermore, their structure was identified on the basis of spectroscopic data. There are three glycoglycerolipids: 1-O-octadecanoic acid-3-O-β-D-galactopyranosyl glycerol (2), 1-O-palmitoyl-3-O-β-D-galactopyranosyl glycerol (4), and 1-O-palmitoyl-2-O-oleoyl-3-O-β-D-galactopyranosyl glycerol (5); two monoglycerides: glycerol monopalmitate (1), 9-hexadecenoic acid, 2,3-dihydroxypropyl ester (3); two terpenoids: loliolide (6) and lsololiolide (7); one lipid-soluble pigments: zeaxanthin (8); one sterol: cholest-5-en-3-ol (9); and one alkaloid: pyrrolopiperazine-2,5-dione (10). These compounds were isolated from U. prolifera for the first time, and compounds 2, 3, 5, and 8 were isolated from marine macroalgae for the first time.
Show more [+] Less [-]Fast determination of 24 steroid hormones in river water using magnetic dispersive solid phase extraction followed by liquid chromatography–tandem mass spectrometry Full text
2016
Zhao, Yong-Gang | Zhang, Yun | Zhan, Ping-Ping | Chen, Xiao Hong | Pan, Sheng-Dong | Jin, Mi-Cong
The easiness-to-handle of the magnetic dispersive solid phase extraction (Mag-dSPE) procedure was developed for preconcentration of 24 steroid hormones in river water. Ethylenediamine-functionalized magnetic carbon nanotubes (EDA@Mag-CNTs) were synthesised by a simple one-pot reaction and were used as sorbent in Mag-dSPE procedure. The properties of the EDA@Mag-CNTs were characterized by transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). An ultra-fast liquid chromatography–tandem quadrupole mass spectrometry (UFLC-MS/MS) method for determination of 24 steroid hormones in river water at nanograms per liter had been developed with pretreatment of the samples by Mag-dSPE. The obtained results demonstrated the higher extraction capacity of EDA@Mag-CNT Mag-dSPE with recoveries between 82.1 and 113 %. The limits of quantification (LOQs) for the steroid hormone were between 0.020 and 1.00 ng/L. The developed method had been successfully applied to 60 river water samples, and it was confirmed that EDA@Mag-CNT Mag-dSPE was a highly effective extraction method for the steroid hormone analyses.
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