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Find video protocols related to scientific articles indexed in Pubmed.
[Analysis of body composition in patients with Crohn's disease].
Zhonghua Wei Chang Wai Ke Za Zhi
PUBLISHED: 10-25-2014
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To investigate the differences in body composition between Crohn's disease(CD) patients and healthy subjects as well as the characteristics of human body composition in various types of CD.
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Altered imprinted gene expression and methylation patterns in mid-gestation aborted cloned porcine fetuses and placentas.
J. Assist. Reprod. Genet.
PUBLISHED: 08-30-2014
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To determine the expression patterns of imprinted genes and their methylation status in aborted cloned porcine fetuses and placentas.
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Impacts of powdered activated carbon addition on trihalomethane formation reactivity of dissolved organic matter in membrane bioreactor effluent.
Chemosphere
PUBLISHED: 08-21-2014
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Characteristics and trihalomethane (THM) formation reactivity of dissolved organic matter (DOM) in effluents from two membrane bioreactors (MBRs) with and without powdered activated carbon (PAC) addition (referred to as PAC/MBR and MBR, respectively) were examined to investigate the effects of PAC addition on THM formation of MBR effluent during chlorination. PAC addition increased the specific UV absorbance. Hydrophobic DOM especially hydrophobic acids in PAC/MBR effluent (50%) were more than MBR effluent (42%). DOM with molecular weight <1kDa constituted 12% of PAC/MBR effluent DOM, which was less than that of MBR effluent (16%). Data obtained from excitation and emission matrix fluorescence spectroscopy revealed that PAC/MBR effluent DOM contained more simple aromatic protein, but had less fulvic acid-like and soluble microbial by-product-like. PAC addition reduced the formation of bromine-containing THMs during chlorination of effluents, but increased THM formation reactivity of effluent DOM.
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Compound bioflocculant and polyaluminum chloride in kaolin-humic acid coagulation: Factors influencing coagulation performance and floc characteristics.
Bioresour. Technol.
PUBLISHED: 07-25-2014
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The objective of this study was to investigate the influence of coagulant dosage and pH on coagulation performance and floc properties using polyaluminum chloride (PAC) and compound bioflocculant (CBF) dual-coagulant in kaolin-humic acid (HA) treatment. Results showed that as PAC dosage rose, comparatively better coagulation efficiencies and floc characteristics were achieved due to stronger charge neutralization and sweeping effect. Addition of CBF could enhance coagulation performance and floc properties, including size, strength and recoverability, except fractal dimension. Solution pH had a significant effect on coagulation efficiencies and flocs formation. Under acidic condition, flocs showed higher strength and recoverability but lower fractal dimension, where charge neutralization was the foremost mechanism. More compact flocs were generated under alkaline condition due to the sweeping effect of hydrolyzed Al species.
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Floc properties and membrane fouling of polyferric silicate chloride and polyferric chloride: the role of polysilicic acid.
Environ Sci Pollut Res Int
PUBLISHED: 07-21-2014
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Impact of polysilicic acid (pSi) in polyferric silicate chloride (PFSiC) on coagulation-ultrafiltration process was investigated in comparison with polyferric chloride (PFC). The Fe(III) species distribution in PFSiC and PFC was measured by a timed complexation spectroscopy method. Characteristics of flocs produced by PFSiC and PFC were studied using a laser diffraction particle sizing device. Moreover, membrane fouling was evaluated using a dead-end batch ultrafiltration unit under two operation modes, coagulation-ultrafiltration (C-UF) and coagulation-sedimentation-ultrafiltration (CSUF). The results indicated that PFSiC with various Si/Fe ratios had better turbidity removal efficiency but inferior organic matter removal. Flocs formed by PFSiC were larger than those by PFC. In case of PFSiC, floc size increased with Si/Fe ratio increasing. PFSiC with various Si/Fe ratios resulted in more compact and weaker flocs than PFC. Ultrafiltration experiments indicated that under C-UF mode, PFSiC with Si/Fe ratios of 0.07 and 0.10 presented better membrane performance than PFC. Under CSUF mode, addition of pSi could alleviate membrane fouling.
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First polar body morphology affects potential development of porcine parthenogenetic embryo in vitro.
Zygote
PUBLISHED: 07-04-2014
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Summary Previous studies have reported that the first polar body (PB1) morphology reflects embryo development competence, but the effects of PB1 on porcine embryo development remain unknown. This study aims to determine whether the ability of porcine embryo development is related to oocytes' PB1 in vitro. The distribution of type II cortical granules (CGs) of porcine matured oocytes in grade B PB1 is significantly greater compared with those in grades A and C PB1 (71.43% versus 52.46% and 50%; P < 0.05). The ratio of porcine parthenogenetic blastocysts and the mean cell number in each blastocyst in the group with grade B PB1 is significantly greater than that with grades A and C PB1 (30.81% vs. 19.02% and 15.15%; P < 0.05) and (36.67 versus 24.67, 28.67; P < 0.05), and no significant differences are found in the embryo cleavage for all groups (79.75%, 84.30%, and 78.18% in grades A, B, and C PB1; P > 0.05). The acetylation level of porcine embryos in the group with grade B PB1 is significantly greater compared with those in the other groups (P < 0.05), and is almost 2.5 times higher than that in grade A. Therefore, porcine oocytes with PB1 in grade B are more competitive in cytoplasmic maturation and further embryo development in vitro.
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Effects of sludge retention times on reactivity of effluent dissolved organic matter for trihalomethane formation in hybrid powdered activated carbon membrane bioreactors.
Bioresour. Technol.
PUBLISHED: 04-01-2014
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In this study, real municipal wastewater intended for reuse was treated by two identical hybrid PAC/MBRs (membrane bioreactors with powdered activated carbon addition), which were operated at sludge retention times (SRTs) of 30 and 180 days, respectively. In order to investigate the effects of SRT on trihalomethane (THM) formation in chlorinated PAC/MBR effluents, characteristics and THM formation reactivity of effluent dissolved organic matter (EfOM) at different SRTs were examined. PAC/MBR-180 had higher level of EfOM, which contained less simple aromatic proteins and exhibited lower specific UV absorbance. EfOM with molecular weight <5 kDa from PAC/MBR-30 (23%) was lower than PAC/MBR-180 (26%). About 50% of EfOM from PAC/MBR-30 was hydrophobic acids, which was higher than that from PAC/MBR-180 (about 36%). EfOM at SRT 180 days exhibited higher hydrophilicity. Prolonging SRT greatly reduced THM formation reactivity of EfOM, but increased the formation of bromine-containing species during chlorination of PAC/MBR effluents.
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Disruption of imprinted gene expression and DNA methylation status in porcine parthenogenetic fetuses and placentas.
Gene
PUBLISHED: 03-17-2014
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Parthenogenetically activated oocytes cannot develop to term in mammals due to the lack of paternal gene expression and failed X chromosome inactivation (XCI). To further characterize porcine parthenogenesis, the expression of 18 imprinted genes was compared between parthenogenetic (PA) and normally fertilized embryos (Con) using quantitative real-time PCR (qRT-PCR). The results revealed that maternally expressed genes were over-expressed, whereas paternally expressed genes were significantly reduced in PA fetuses and placentas. The results of bisulfite sequencing PCR (BSP) demonstrated that PRE-1 and Satellite were hypermethylated in both Con and PA fetuses and placentas, while XIST DMRs were hypomethylated only in PA samples. Taken together, these results suggest that the aberrant methylation profile of XIST DMRs and abnormal imprinted gene expression may be responsible for developmental failure and impaired growth in porcine parthenogenesis.
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Adsorption of ammonium and phosphate by feather protein based semi-interpenetrating polymer networks hydrogel as a controlled-release fertilizer.
Environ Technol
PUBLISHED: 03-08-2014
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A new feather protein-grafted poly(potassium acrylate)/polyvinyl alcohol (FP-g-PKA/PVA) semi-interpenetrating polymer networks (semi-IPNs) hydrogel was produced through graft copolymerization with FP as a basic macromolecular skeletal material, acrylic acid as a monomer and PVA as a semi-IPNs polymer. The adsorption of ammonium and phosphate ions from aqueous solution using the new hydrogel as N and P controlled-release fertilizer with water-retention capacity was studied. The effects of pH value, concentration, contact time and ion strength on NH4+ and PO3-4 removal by FP-g-PKA/PVA semi-IPNs hydrogel were investigated using batch adsorption experiments. The results indicated that the hydrogel had high adsorption capacities and fast adsorption rates for NH4+ and PO3-4 in wide pH levels ranging from 4.0 to 9.0. Kinetic analysis presented that both NH4+ and PO3-4 removal were closely fitted with the pseudo-second-order model. Furthermore, the adsorption isotherms of hydrogel were best represented by the Freundlich model. The adsorption-desorption experimental results showed the sustainable stability of FP-g-PKA/PVA semi-IPNs hydrogel for NH4+ and PO3-4 removal. Overall, FP-g-PKA/PVA could be considered as an efficient material for the removal and recovery of nitrogen and phosphorus with the agronomic reuse as a fertilizer.
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The role of sodium alginate in improving floc size and strength and the subsequent effects on ultrafiltration membrane fouling.
Environ Technol
PUBLISHED: 03-08-2014
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Dosing environment-friendly polymer as coagulant aids is an encouraging method in water treatment to obtain desirable floc characteristics. Sodium alginate (SA) was used as the coagulant aid for synthetic humic acid (HA) water treatment to investigate the effect on flocs characteristics and ultrafiltration (UF) membrane fouling.
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Genomic imprinting analysis of Igf2/H19 in porcine cloned fetuses using parthenogenetic somatic cells as nuclear donors.
Biotechnol. Lett.
PUBLISHED: 02-28-2014
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To gain insight into parthenogenesis in pigs, we report for the first time that using parthenogenetic somatic cells as nuclear donors (PSCNT), the porcine parthenogenetic fetus can develop to gestational day 39. Weight and morphological analysis revealed that PSCNT fetuses were smaller and developmentally retarded when compared to normally fertilized controls. Quantitative gene expression analysis indicated that in PSCNT fetuses, H19 was over-expressed, whereas Igf2 was significantly reduced (p < 0.05) compared with their controls. In addition, bisulfite-sequencing PCR results demonstrated that H19 differentially DNA methylated regions (DMRs) were hypomethylated in PSCNT fetuses, while Igf2 DMRs were hypermethylated in both PSCNT and control fetuses. Our results suggest that extended development of the porcine parthenogenetic fetus can be accomplished using PSCNT and that abnormal DNA methylation of H19 DMRs might contribute to the critical barrier of parthenogenesis in pigs.
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Influences of dissolved organic matter characteristics on trihalomethanes formation during chlorine disinfection of membrane bioreactor effluents.
Bioresour. Technol.
PUBLISHED: 02-23-2014
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Dissolved organic matter (DOM) in MBR-treated municipal wastewater intended for reuse was fractionated through ultrafiltration and XAD-8 resin adsorption and characterized by fluorescence spectroscopy. To probe the influences of DOM characteristics on trihalomethanes (THMs) formation reactivity during chlorination, THMs yield and speciation of DOM fractions was investigated. It was found that chlorine reactivity of DOM decreased with the decrease of molecular weight (MW), and MW>30kDa fractions produced over 55% of total THMs in chlorinated MBR effluent. Hydrophobic organics had much higher THMs formation reactivity than hydrophilic substances. Particularly, hydrophobic acids exhibited the highest chlorine reactivity and contributed up to 71% of total THMs formation. Meanwhile, low-MW and hydrophilic DOM were susceptible to produce bromine-containing THMs. Of the fluorescent DOM in MBR effluent, aromatic moieties and humic acid-like had higher chlorine reactivity. Conclusively, macromolecular and hydrophobic organics containing aromatic moieties and humic acid-like must be removed to reduce THMs formation.
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Effects of compound bioflocculant on coagulation performance and floc properties for dye removal.
Bioresour. Technol.
PUBLISHED: 02-23-2014
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A series of jar tests was conducted to investigate the coagulation performance of using compound bioflocculant (CBF) as a coagulant aid with aluminum sulfate (AS) and polyaluminum chloride (PAC) in synthetic dyeing wastewater treatment. Floc size, growth, breakage, re-growth and sedimentation natural were investigated by PDA2000. The results showed that the corresponding dual-coagulants of AS and PAC enhanced the color removal efficiency, especially at low aluminum dosage. Results also indicated that the floc generated by aluminum salts and CBF had larger size and higher growth rate. In addition, for both AS and PAC the floc recoverability was improved by addition of CBF. The adsorption and bridging effect of CBF performed a positive role in dye wastewater treatment.
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Characterization and swelling-deswelling properties of wheat straw cellulose based semi-IPNs hydrogel.
Carbohydr Polym
PUBLISHED: 02-22-2014
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A novel wheat straw cellulose-g-poly(potassium acrylate)/polyvinyl alcohol (WSC-g-PKA/PVA) semi-interpenetrating polymer networks (semi-IPNs) hydrogel was prepared by polymerizing wheat straw and an aqueous solution of acrylic acid (AA), and further semi-interpenetrating with PVA occurred during the chemosynthesis. The swelling and deswelling properties of WSC-g-PKA/PVA semi-IPNs hydrogel and WSC-g-PKA hydrogel were studied and compared in various pH solutions, salt solutions, temperatures, particle sizes and ionic strength. The results indicated that both hydrogels had the largest swelling capacity at pH=6, and the effect of ions on the swelling of hydrogels was in the order: Na(+)>K(+)>Mg(2+)>Ca(2+). The Schott's pseudo second order model can be effectively used to evaluate swelling kinetics of hydrogels. Moreover, the semi-IPNs hydrogel had improved swelling-deswelling properties compared with that of WSC-g-PKA hydrogel.
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MicroRNA expression profile and functional analysis reveal that miR-206 is a critical novel gene for the expression of BDNF induced by ketamine.
Neuromolecular Med.
PUBLISHED: 02-19-2014
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Depression is a major social and health concern, and ketamine exerts a quick, remarkable and persistent anti-depressive effect. microRNAs (miRNAs) show remarkable potential in the treatment of clinical depression. Here, we determined the expression profile of miRNAs in the hippocampus of rats treated with ketamine (15 mg/kg). The results suggest that multiple miRNAs were aberrantly expressed in rat hippocampus after ketamine injection (18 miRNAs were significantly reduced, while 22 miRNAs were significantly increased). Among them, miR-206 was down-regulated in ketamine-treated rats. In both cultured neuronal cells in vitro and hippocampus in vivo, we identified that the brain-derived neurotrophic factor (BDNF) was a direct target gene of miR-206. Via this target gene, miR-206 strongly modulated the expression of BDNF. Moreover, overexpression of miR-206 significantly attenuated ketamine-induced up-regulation of BDNF. The results indicated that miRNA-206 was involved in novel therapeutic targets for the anti-depressive effect of ketamine.
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Study of Enteromorpha polysaccharides as a new-style coagulant aid in dye wastewater treatment.
Carbohydr Polym
PUBLISHED: 02-18-2014
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Enteromorpha is one of the common fouling green algae, which has brought serious environmental problems in past years. This study was aimed to apply it in water treatment process. Enteromorpha polysaccharides (Ep) were used as a new-style coagulant aid to assess its effect on coagulation behavior and floc characteristics. Color removal was used to evaluate coagulation effects and floc properties were investigated by Photometric Dispersion Analyzer (PDA). Results showed that when Ep was used in combination with aluminum chloride (AC), color removal could be apparently improved, and the optimal solution pH ranged 6.0-8.0. The growth rate and average size of flocs formed by AC-Ep were larger than those by AC in steady-state after floc growth phase, and meanwhile the distribution of floc size had a wider range. Besides, floc recoverability could be significantly improved when Ep was used as coagulant aid.
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The placental specific gene, PLAC1, is induced by the Epstein-Barr virus and is expressed in human tumor cells.
Virol. J.
PUBLISHED: 02-05-2014
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The Epstein-Barr virus (EBV) is a causal agent in a number of malignancies in humans including hematopoietic tumors and non-hematopoietic tumors. Burkitt's lymphoma cell lines containing the Epstein-Barr virus have been shown to form tumors in nude mice while clonal derivatives of such cell lines in which the viral genome has been lost do not (JID 177: 1194-1201, 1998; JV 72: 9150-9156, 1998; JV 68: 6069-6073, 1994). The re-introduction of EBV into these EBV negative BLs reconstitutes the tumor phenotype. Thus, EBV-induced cellular genes play critical role in EBV-related tumors.
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Global Bidirectional Transcription of the Epstein-Barr Virus Genome During Reactivation.
J. Virol.
PUBLISHED: 11-20-2013
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Epstein-Barr Virus (EBV) reactivation involves the ordered induction of approximately 90 viral genes that participate in the generation of infectious virions. Using strand specific RNA-seq to assess the EBV transcriptome during reactivation, we found extensive bidirectional transcription extending across nearly the entire genome. In contrast, only 4% of the EBV genome is currently bidirectionally annotated. Most of the newly identified transcribed regions show little evidence of coding potential, supporting noncoding roles for most of these RNAs. Based on previous cellular long noncoding RNA size calculations, we estimate that there are likely hundreds more EBV genes expressed during reactivation than was previously known. Limited 5 and 3 rapid amplification of cDNA ends (RACE) experiments and findings of novel splicing events by RNA-seq suggest that the complexity of the viral genome during reactivation may be even greater. Further analysis of antisense transcripts at some of the EBV latency gene loci showed that they are "late" genes, they are nuclear, and they tend to localize in areas of the nucleus where others find newly synthesized viral genomes. This raises the possibility that these transcripts perform functions such as new genome processing, stabilization, organization, etc. The finding of a significantly more complex EBV transcriptome during reactivation changes our view of the viral production process from one that is facilitated and regulated almost entirely by previously identified viral proteins to a process that also involves the contribution of a wide array of virus encoded noncoding RNAs.
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Enhanced adsorption of chromium onto activated carbon by microwave-assisted H3PO4 mixed with Fe/Al/Mn activation.
J. Hazard. Mater.
PUBLISHED: 09-04-2013
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FeCl3, AlCl3 and MnCl2 were used as the assisted activation agent in activated carbon preparation by H3PO4 activation using microwave heating method. The physico-chemical properties of activated carbons were investigated by scanning electron microscope (SEM), N2 adsorption/desorption, Boehms titration, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). To investigate the adsorption performances of chromium onto these newly developed activated carbons, a batch of experiments were performed under different adsorption conditions: solution pH, initial Cr(VI) ion concentration, contact time and co-existing ions. The results suggested that carbon with MnCl2 as assisted activation agent displayed the highest BET surface area (1332m(2)/g) and the highest pore volume (1.060cm(3)/g). FeCl3, AlCl3 and MnCl2 had successfully improved Cr(VI) adsorption and activated carbon with FeCl3 as assisted activation agent exhibited the best uptake capacity. To study the transformation of Cr(VI) in adsorption process, total chromium in the aqueous solution was also recorded. The ratio of the amount of Cr(VI) to Cr(III) on each adsorbent was explained by XPS analysis results. Both the co-existing salts (Na2SO4 and NaNO3) demonstrated promoted effects on Cr(VI) removal by four carbons. The pseudo-second-order model and Freundlich equation displayed a good correlation with adsorption data.
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The dye or humic acid water treatment and membrane fouling by polyaluminum chloride composited with sodium alginate in coagulation-ultrafiltration process.
Water Sci. Technol.
PUBLISHED: 05-17-2013
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Composite flocculants have been extensively studied and applied in recent years in order to improve the water treatment efficiency. In this study, a new composite flocculant prepared by polyaluminum chloride (PAC) and sodium alginate (SA) was used to treat dye and humic acid water in the coagulation-ultrafiltration process. The subsequent effects of PAC/SA on ultrafiltration membrane fouling were investigated by calculating the Modified Fouling Index (MFI). The results showed that the application of PAC/SA could not only restrict the membrane fouling but also improve the removal efficiency of the coagulation-ultrafiltration process. MFI of PAC/SA was the lowest, followed by PAC and the raw water for coagulated effluents filtered by ultrafiltration membrane. For example, MFI of PAC/SA was 0.40 s mL(-2) for reactive blue KGL (denoted as RB-KGL) treatment, while that of PAC was 2.26 s mL(-2). The removal efficiencies were improved as coagulation was used as pretreatment of ultrafiltration membrane. And PAC/SA could form the higher removal efficiency than PAC, especially for RB-KGL. The color removal efficiency of PAC/SA was 96.36% for RB-KGL treated by coagulation-ultrafiltration process, which was higher than that of PAC (85.62%).
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OncomiR addiction is generated by a miR-155 feedback loop in Theileria-transformed leukocytes.
PLoS Pathog.
PUBLISHED: 04-01-2013
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The intracellular parasite Theileria is the only eukaryote known to transform its mammalian host cells. We investigated the host mechanisms involved in parasite-induced transformation phenotypes. Tumour progression is a multistep process, yet oncogene addiction implies that cancer cell growth and survival can be impaired by inactivating a single gene, offering a rationale for targeted molecular therapies. Furthermore, feedback loops often act as key regulatory hubs in tumorigenesis. We searched for microRNAs involved in addiction to regulatory loops in leukocytes infected with Theileria parasites. We show that Theileria transformation involves induction of the host bovine oncomiR miR-155, via the c-Jun transcription factor and AP-1 activity. We identified a novel miR-155 target, DET1, an evolutionarily-conserved factor involved in c-Jun ubiquitination. We show that miR-155 expression led to repression of DET1 protein, causing stabilization of c-Jun and driving the promoter activity of the BIC transcript containing miR-155. This positive feedback loop is critical to maintain the growth and survival of Theileria-infected leukocytes; transformation is reversed by inhibiting AP-1 activity or miR-155 expression. This is the first demonstration that Theileria parasites induce the expression of host non-coding RNAs and highlights the importance of a novel feedback loop in maintaining the proliferative phenotypes induced upon parasite infection. Hence, parasite infection drives epigenetic rewiring of the regulatory circuitry of host leukocytes, placing miR-155 at the crossroads between infection, regulatory circuits and transformation.
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Preparation of wheat straw based superabsorbent resins and their applications as adsorbents for ammonium and phosphate removal.
Bioresour. Technol.
PUBLISHED: 03-29-2013
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A novel wheat straw cellulose-g-poly (potassium acrylate)/polyvinyl alcohol (WSC-g-PKA/PVA) semi-interpenetrating polymer networks (semi-IPNs) superabsorbent resin (SAR) was prepared by graft copolymerization. The structure and performance of the WSC-g-PKA/PVA semi-IPNs SAR was studied and compared with those of wheat straw cellulose-g-poly (potassium acrylate) (WSC-g-PKA) SAR. The effects of various experimental parameters such as solution pH, concentration, contact time and ion strength on NH4(+) and PO4(3-) removal from solutions were investigated. Equilibrium isotherm data of adsorption of both NH4(+) and PO4(3-) were well fitted to the Freundlich model. Kinetic analysis showed that the pseudo-second-order kinetic model was more suitable for describing the whole adsorption process of NH4(+) and PO4(3-) on SARs. Overall, WSC-g-PKA/PVA semi-IPNs SAR showed better properties in comparison with WSC-g-PKA SAR and it could be considered as one efficient material for the removal and recovery of nitrogen and phosphorus with the agronomic reuse as a fertilizer.
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Uptake of perchlorate from aqueous solutions by amine-crosslinked cotton stalk.
Carbohydr Polym
PUBLISHED: 03-23-2013
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Virgin cotton stalk was produced into an effective biosorbent for perchlorate adsorption. Surface analysis including BET surface area and SEM illustrated the reduction of porous structure in amine-crosslinked cotton stalk (AC-CS). Elemental and zeta potential analysis validated the graft of some positively charged amine groups on surface of AC-CS. Spectra analysis (XPS, FTIR and Raman spectra) suggested that interaction between AC-CS and ClO4(-) should be based on electrostatic attraction. The maximum adsorption capacity (qmax) of AC-CS for perchlorate at different pHs (3.0, 6.0, 9.0 and 11.0) were calculated as 29.6, 42.6, 41.0 and 33.0 mg/g, respectively. The saturated perchlorate uptakes in column were in range of 25.0-38.1 mg/g at different pHs. In addition, the exhausted AC-CS column was regenerated by 0.5 mol/L of NaCl solution, which was adequate for almost complete desorption of the perchlorate.
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Application and advantages of novel clay ceramic particles (CCPs) in an up-flow anaerobic bio-filter (UAF) for wastewater treatment.
Bioresour. Technol.
PUBLISHED: 03-12-2013
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Utilization of clay ceramic particles (CCPs) as the novel filter media employed in an up-flow anaerobic bio-filter (UAF) was investigated. After a series of tests and operations, CCPs have presented higher total porosity and roughness, meanwhile lower bulk and grain density. When CCPs were utilized as fillers, the reactor had a shorter start up period of 45 days comparing with conventional reactors, and removal rate of chemical oxygen demand (COD) still reached about 76% at a relatively lower temperature during the stable state. In addition, degradation of COD and ammonia nitrogen (NH4-N) at different media height along the reactor was evaluated, and the dates showed that the main reduction process happened within the first 30 cm media height from the bottom flange. Five phases were observed according to different organic loadings during the experiment period, and the results indicated that COD removal increased linearly when the organic loading was increased.
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Floc characterization and membrane fouling of polyferric-polymer dual/composite coagulants in coagulation/ultrafiltration hybrid process.
J Colloid Interface Sci
PUBLISHED: 03-05-2013
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Papermaking sludge and spent pickling liquor were recycled to synthesize a macromolecular lignin-acrylamide polymer (LA) and polyferric chloride (PFC), respectively. The dual-coagulant PFC-LA (PFC and LA were dosed orderly), composite coagulant PFCLA (PFC and LA premixed before dosed) and PFC were used in coagulation/ultrafiltration hybrid process in surface water treatment. The objectives of this paper are to comparatively investigate final water quality after coagulation and coagulation/ultrafiltration process and floc properties, including floc size, strength, recoverability and floc structure, with or without LA addition. Additionally, the relationship between membrane fouling and floc characteristics was discussed. The results showed that best final water quality was obtained by PFC-LA, sequentially followed by PFCLA and PFC. Floc size, growth rate, strength and recoverability as well as fractal dimension were also in the order of PFC-LA>PFCLA>PFC. The maximum permeate fluxes before and after backwash operation were obtained by PFC-LA, which gave the largest and most compact flocs. Coagulation suspension after breakage resulted in much more serious membrane fouling for PFC, whereas permeate flux slightly decreased when LA was used in combination with PFC.
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Characterization of size, strength and structure of aluminum-polymer dual-coagulant flocs under different pH and hydraulic conditions.
J. Hazard. Mater.
PUBLISHED: 03-05-2013
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The objectives of this study are to investigate the impact of papermaking sludge product (LA) on coagulation performance and floc properties under different solution pH and hydraulic conditions. LA was synthetized by grafting acrylamide onto the lignin that contained in papermaking sludge. Characterization of LA, such as FTIR, SEM, zeta potential and molecular weight, showed that target product was obtained successfully. LA was used in combination with aluminum sulfate or polyaluminum chloride, namely Al-LA (Al was dosed firstly) and LA-Al (LA was dosed firstly), in humic acid water treatment. Floc properties and coagulation behaviors of aluminum salts and the dual-coagulants were comparatively evaluated. Results showed that DOC removal was improved by LA at pH 4 ~ 9 and the removal variations caused by different pH were decreased. Flocs formed at pH 5 and pH 8 gave quite large floc size. Floc recoverability declined as initial pH increased. Floc size, growth rate and recoverability were in the order of Al-LA>LA-Al>Al. Furthermore, flocs formed at pH 7 showed the weakest resistance to increasing shear force. Fractal dimension was rather high at pH 7 and 8 and it was in the following order: Al>LA-Al>Al-LA.
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Effects of dissolved organic matter size fractions on trihalomethanes formation in MBR effluents during chlorine disinfection.
Bioresour. Technol.
PUBLISHED: 02-27-2013
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In this study, effects of dissolved organic matter (DOM) size fractions on trihalomethanes (THMs) formation in MBR effluents during chlorination were investigated by fractionating DOM into >100, 30-100, 10-30, 5-10 and <5 kDa fractions using ultrafiltration (UF) membranes based on molecular weight (MW). Fractions of MW>30 kDa constituted 87% of DOM and were the main THMs precursors, which exhibited higher specific ultraviolet absorbance (SUVA) and THMs formation potential (THMFP) and should be reduced to control THMs formation. For these fractions, THMs formation was mostly attributed to slow chlorine decay, and THMs yield coefficients were low because halogenated intermediates derived from the macromolecular DOM were difficult to decompose to produce THMs. Moreover, there was a strong linear correlation between dissolved organic carbon (DOC) concentration and THMFP (R(2)=0.981), as well as between the SUVA and specific THMFP (R(2)=0.993) in all fractions.
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Synthesis of wheat straw cellulose-g-poly (potassium acrylate)/PVA semi-IPNs superabsorbent resin.
Carbohydr Polym
PUBLISHED: 01-17-2013
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To better use wheat straw and minimize its negative impact on environment, a novel semi-interpenetrating polymer networks (semi-IPNs) superabsorbent resin (SAR) composed of wheat straw cellulose-g-poly (potassium acrylate) (WSC-g-PKA) network and linear polyvinyl alcohol (PVA) was prepared by polymerization in the presence of a redox initiating system. The structure and morphology of semi-IPNs SAR were characterized by means of FTIR, SEM and TGA, which confirmed that WSC and PVA participated in the graft polymerization reaction with acrylic acid (AA). The factors that can influence the water absorption of the semi-IPNs SAR were investigated and optimized, including the weight ratios of AA to WSC and PVA to WSC, the content of initiator and crosslinker, neutralization degree (ND) of AA, reaction temperature and time. The semi-IPNs SAR prepared under optimized synthesis condition gave the best water absorption of 266.82 g/g in distilled water and 34.32 g/g in 0.9 wt% NaCl solution.
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Nitrate removal from aqueous solution by Arundo donax L. reed based anion exchange resin.
J. Hazard. Mater.
PUBLISHED: 09-26-2011
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Arundo donax L. reed based anion exchange resin (ALR-AE resin) was prepared by the amination reaction for the adsorption of nitrate from aqueous solution. The physicochemical properties of the ALR-AE resin as well as its adsorption properties for nitrate were measured. Results indicated that large amounts of amine groups have been grafted onto the structure of the resin. The FTIR and Raman spectra validated the ion exchange mechanism for nitrate adsorption by ALR-AE resin. The adsorption data showed an exothermic nature for the adsorption of nitrate by ALR-AE resin, and the equilibrium time for the adsorption process was about 10 min. The maximum adsorption capacity (Q(max)) for nitrate was 44.61 mg/g. The saturated adsorption capacity of ALR-AE resin in column was about 38.9 mg/g, which accounted for about 87.2% of the resins Q(max). The preferential adsorption capacity of the ALR-AE resin followed the order as: SO(4)(2-)>NO(3)(-) ? PO(4)(3-)>NO(2)(-). In addition, the utilization of the resin in actual water samples indicated that the ALR-AE resin could be used for the treatment of many ionic polluted wastewaters.
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Preparation and mechanism of the sintered bricks produced from Yellow River silt and red mud.
J. Hazard. Mater.
PUBLISHED: 09-14-2011
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The preparation, characteristics and mechanisms of sintered bricks manufactured by Yellow River silt and red mud were studied. The sintering shrinkage, weight loss on ignition, water absorption and compressive strength were tested to determine the optimum preparation condition. Sintering mechanisms were discussed through linear regression analysis. Crystalline components of raw materials and bricks were analyzed by X-ray diffraction. Leaching toxicity of raw materials and bricks were measured according to sulphuric acid and nitric acid method. Radiation safety of the sintered bricks was characterized by calculating internal exposure index and external exposure index. The results showed that at the chosen best parameters (red mud content of 40%, sintering temperature of 1050°C and sintering time of 2h), the best characteristics of sintered bricks could be obtained. The weight loss on ignition of sintered bricks was principally caused by the removal of absorbed water and crystal water. The sintering shrinkage of sintered bricks mainly depended on sodium compounds and iron compounds of red mud. The sintering process made some components of raw materials transform into other crystals having better thermostability. Besides, the leaching toxicity and radioactivity index of sintered bricks produced under the optimum condition were all below standards.
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Preparation of activated carbon derived from cotton linter fibers by fused NaOH activation and its application for oxytetracycline (OTC) adsorption.
J Colloid Interface Sci
PUBLISHED: 09-09-2011
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The objective of this research is to produce high surface area-activated carbon derived from cotton linter fibers by fused NaOH activation and to examine the feasibility of removing oxytetracycline (OTC) from aqueous solution. The cotton linter fibers activated carbon (CLAC) was characterized by N(2) adsorption/desorption isotherms, Fourier transform infrared spectroscopy (FTIR), and scanning electron microscope (SEM). The results showed that CLAC had a predominantly microporous structure with a large surface area of 2143 m(2)/g. The adsorption system followed pseudo-second-order kinetic model, and equilibrium was achieved within 24h. The equilibrium data were described well by Langmuir isotherm. Thermodynamic study showed that the adsorption was exothermic reaction at low concentration and became endothermic nature with the concentration increasing. Competitive adsorption took place in the weakly acidic to neutral conditions. Under the strong acidity or strong alkaline condition, the adsorption of the oxytetracycline was hindered by electrostatic repulsion. The adsorption mechanism depended on the pH of the solutions as well as the pK(a) of the oxytetracycline.
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Adsorption of hexavalent chromium from aqueous solution by modified corn stalk: a fixed-bed column study.
Bioresour. Technol.
PUBLISHED: 09-02-2011
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Continuous fixed-bed column studies were carried out by using modified corn stalk (MCS) as an adsorbent for the removal of Cr(VI) from aqueous solution. The effect of various parameters like bed depths (1.4, 2.2 and 2.9 cm), flow rate (5, 10 and 15 mL/min), influent Cr(VI) concentrations (100, 200 and 300 mg/L) and influent solution pH (2.66, 4.91 and 5.66) was investigated. The exhaustion time increased with increase of bed depth, decrease of flow rate and influent concentration. The Adams-Bohart, Thomas and Yoon-Nelson models were applied to the adsorption under varying experimental conditions to predict the breakthrough curves and to evaluate the model parameters of the fixed-bed column that are useful for process design. The Thomas and Yoon-Nelson models were in good agreement with the experimental data. The MCS column study states the value of the excellent adsorption capacity for the removal of Cr(VI) from aqueous solution.
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Effect of dosing sequence and solution pH on floc properties of the compound bioflocculant-aluminum sulfate dual-coagulant in kaolin-humic acid solution treatment.
Bioresour. Technol.
PUBLISHED: 08-30-2011
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The compound bioflocculant (CBF)-aluminum sulfate (AS) dual-coagulant and AS were comparatively studied for the coagulation of kaolin-humic acid solution. Floc properties including floc growth rate, size, strength, recoverability and fractal dimension under different pH conditions were investigated by Mastersizer 2000. Results indicated that, the flocs formed by AS-CBF (AS dosed first) showed the largest size and the best recoverability across the pH range investigated. While flocs formed by CBF-AS gave the most compact structure. The three coagulants exhibited similar floc growth rate and strength. Moreover, flocs formed in acidic conditions were stronger and more recoverable but showed lower growth rate, smaller size and looser structure compared to those formed at pH>6 regardless of the coagulant used. Charge neutralization was the dominant mechanism for AS at low pH, while the coagulation mechanism transformed to enmeshment as the pH increased. There was an additional adsorption bridging effect for AS-CBF and CBF-AS.
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Influences of two antibiotic contaminants on the production, release and toxicity of microcystins.
Ecotoxicol. Environ. Saf.
PUBLISHED: 07-28-2011
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The influences of spiramycin and amoxicillin on the algal growth, production and release of target microcystins (MCs), MC-LR, MC-RR and MC-YR, in Microcystis aeruginosa were investigated through the seven-day exposure test. Spiramycin were more toxic to M. aeruginosa than amoxicillin according to their 50 percent effective concentrations (EC(50)) in algal growth, which were 1.15 and 8.03 ?g/l, respectively. At environmentally relevant concentrations of 100 ng/l-1 ?g/l, spiramycin reduced the total MC content per algal cell and inhibited the algal growth, while exposure to amoxicillin led to increases in the total MC content per algal cell and the percentage of extracellular MCs, without affecting the algal growth. Toxicity of MCs in combination with each antibiotic was assessed in the luminescent bacteria test using the toxic unit (TU) approach. The 50 percent effective concentrations for the mixtures (EC(50mix)) were 0.56 TU and 0.48 TU for MCs in combination with spiramycin and amoxicillin, respectively, indicating a synergistic interaction between MCs and each antibiotic (EC(50mix)<1TU). After seven-day exposure to 100 ng/l-1 ?g/l of antibiotics, spiramycin-treated algal media and amoxicillin-treated algal media showed significantly lower (p<0.05) and higher (p<0.05) inhibition on the luminescence of Photobacterium phosphoreum, respectively, compared with the untreated algal medium. These results indicated that the toxicity of MCs were alleviated by spiramycin and enhanced by amoxicillin, and the latter effect would increase threats to the aquatic environment.
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Properties improvement of paper mill sludge-based granular activated carbon fillers for fluidized-bed bioreactor by bentonite (Na) added and acid washing.
J. Hazard. Mater.
PUBLISHED: 06-17-2011
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Properties improvement of paper mill sludge (PMS) based granular activated carbon fillers for fluidized-bed bioreactor (FBBR) was investigated in this study. Bentonite (Na) powders were blended in the dewatered paper mill sludge powders to strengthen the abrasion resistance strength of the fillers. Different acid washing treatments were studied to produce FBBR fillers with optimum performance. The results indicated that granulation was easy and the abrasion resistance strength of the fillers increased by 15% with 8 wt% of bentonite (Na) added. Acid washing treatment prior to activation had a better effect on the removal of Fe than post-activation acid washing treatment. HCl was the most appropriate acid during the acid washing treatment. The optimum acid washing treatment was carried out prior to activation with 2M HCl soaking for 6h. After acid washing treatment, the fillers with grain density of 1170 kg/m(3), specific surface area of 176 m(2)/g were obtained.
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Characterization of peripheral blood T lymphocyte subsets in Chinese rhesus macaques with repeated or long-term infection with Plasmodium cynomolgi.
Parasitol. Res.
PUBLISHED: 05-20-2011
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T lymphocytes play a vital role in antimalaria immunity, but there is little information about the role of T cells in malaria infection. In order to explore the profile of T cells in malaria immunity, we infected Chinese rhesus macaques with the malaria parasite (Plasmodium cynomolgi) and examined the dynamics of T cell subsets. Both repeated and long-term infections were involved. Our results showed that the monkeys in the repeated infection group acquired protective immunity through primary infection, which was evidenced by a much lower parasitemia, milder anemia, and milder fever during reinfection; the monkeys in the long-term infection group also developed protective immunity, but this was not sufficient to eliminate the parasite. The total counts of leukocytes, neutrophils, CD3+ T cells, CD4+ or CD8+ T cells, and naïve and memory CD4+ and CD8+ T cells declined during the acute phase of malaria but increased after the parasite was controlled. The total number of activated CD4+ T cells significantly increased during malaria in animals with a long-term infection, which remained at least 3 months after the termination of malaria. However, the activated CD4+ T cells decreased during the acute phase of infection in the repeated infection group and converted to preinfection levels after malaria was cured. Regulatory CD4+ T cells continued to increase during the malaria infections and quickly reverted to preinfection levels after the parasite was controlled. Our study provides a systematic analysis of the kinetic profiles of T lymphocyte subsets during malaria infections and provides some experimental insight into malaria immunology.
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Antitumor effect of malaria parasite infection in a murine Lewis lung cancer model through induction of innate and adaptive immunity.
PLoS ONE
PUBLISHED: 05-18-2011
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Lung cancer is the most common malignancy in humans and its high fatality means that no effective treatment is available. Developing new therapeutic strategies for lung cancer is urgently needed. Malaria has been reported to stimulate host immune responses, which are believed to be efficacious for combating some clinical cancers. This study is aimed to provide evidence that malaria parasite infection is therapeutic for lung cancer.
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The impact of pH on floc structure characteristic of polyferric chloride in a low DOC and high alkalinity surface water treatment.
Water Res.
PUBLISHED: 05-16-2011
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The adjustment of pH is an important way to enhance removal efficiency in coagulation units, and in this process, the floc size, strength and structure can be changed, influencing the subsequent solid/liquid separation effect. In this study, an inorganic polymer coagulant, polyferric chloride (PFC) was used in a low dissolved organic carbon (DOC) and high alkalinity surface water treatment. The influence of coagulation pH on removal efficiency, floc growth, strength, re-growth capability and fractal dimension was examined. The optimum dosage was predetermined as 0.150 mmol/L, and excellent particle and organic matter removal appeared in the pH range of 5.50-5.75. The structure characteristics of flocs formed under four pH conditions were investigated through the analysis of floc size, effect of shear and particle scattering properties by a laser scattering instrument. The results indicated that flocs formed at neutral pH condition gave the largest floc size and the highest growth rate. During the coagulation period, the fractal dimension of floc aggregates increased in the first minutes and then decreased and larger flocs generally had smaller fractal dimensions. The floc strength, which was assessed by the relationship of floc diameter and velocity gradient, decreased with the increase of coagulation pH. Flocs formed at pH 4.00 had better recovery capability when exposed to lower shear forces, while flocs formed at neutral and alkaline conditions had better performance under higher shear forces.
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Transition of tumor-associated macrophages from MHC class II(hi) to MHC class II(low) mediates tumor progression in mice.
BMC Immunol.
PUBLISHED: 05-07-2011
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Tumor-associated macrophages (TAMs) are the most abundant immune cells within the tumor stroma and play a crucial role in tumor development. Although clinical investigations indicate that high levels of macrophage (M?) infiltration into tumors are associated with a poor prognosis, the exact role played by TAMs during tumor development remains unclear. The present study aimed to investigate dynamic changes in TAM major histocompatibility complex (MHC) class II expression levels and to assess the effects of these changes on tumor progression.
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Characteristics of diethylenetriamine-crosslinked cotton stalk/wheat stalk and their biosorption capacities for phosphate.
J. Hazard. Mater.
PUBLISHED: 04-15-2011
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Two polymeric biosorbents were prepared from cotton stalk (CS) and wheat straw (WS) by the epichlorohydrin-diethylenetriamine-trimethylamine method. Amine-crosslinked cotton stalk (AC-CS) and wheat stalk (AC-WS) were used for the adsorption of phosphate, and their physicochemical properties as well as biosorption properties for phosphate were discussed intensively. Results indicated that the contents of holocellulose in CS and WS corresponded to the distinct phosphate adsorption capacities between AC-CS and AC-WS. Zeta potential and Raman spectra analysis illustrated the electrostatic attraction between phosphate ions and biosorbents. The adsorption of phosphate was not strongly pH dependent when the pH was about 4.0-9.0. The Langmuir isotherm provided the better fit and the maximum adsorption capacity (Q(max)) was 51.54 mg/g for AC-CS and 60.61 mg/g for AC-WS. The saturated adsorption capacities of AC-CS and AC-WS in column were 49.05 and 41.9 mg/g, which accounted for about 80.3% and 81.4% of these biosorbentsQ(max). NaCl and HCl solutions demonstrated the excellent regeneration capacities for the biosorbents, and after three times of adsorption-desorption cycles, the column adsorption capacities of these biosorbents were still higher than 92%.
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Influence of floc size and structure on membrane fouling in coagulation-ultrafiltration hybrid process--the role of Al13 species.
J. Hazard. Mater.
PUBLISHED: 04-14-2011
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Coagulation application prior to ultrafiltration process was carried out to increase humic acid (HA) removal and membrane permeability. The [Al(13)O(4)(OH)(24)(H(2)O)(12)](7+) polycation (Al(13) species) was used in the coagulant process and polyaluminum chloride (PACl) was also used for comparison. Characteristics of aggregates pre-coagulated by Al(13) species and PACl were investigated using a laser diffraction particle sizing device. Additionally, membrane fouling was investigated under different coagulation conditions. The various resistances caused by Al(13) and PACl treatment effluents were determined using the membrane fouling index equation. The results indicated that at dose of 1 and 3mg/L, Al(13) produced larger flocs than PACl; while when dosage further increased, the PACl-HA flocs were much larger. The flocs formed by Al(13) were strong and compact, and those formed by PACl were weak and loosely structured with the exception of the flocs generated at 1mg/L. The investigation of membrane fouling demonstrated that Al(13) contributed to the best effluent permeating at 5mg/L and the corresponding dose for PACl was 7 mg/L. The adsorption resistance of effluent pre-treated by Al(13) accounted for a smaller percentage of the total resistances compared with that by PACl.
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Performance of dithiocarbamate-type flocculant in treating simulated polymer flooding produced water.
J Environ Sci (China)
PUBLISHED: 04-12-2011
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Produced water from polymer flooding is difficult to treat due to its high polymer concentration, high viscosity, and emulsified characteristics. The dithiocarbamate flocculant, DTC (T403), was prepared by the amine-terminated polyoxypropane-ether compound known as Jeffamine-T403. The product was characterized by IR spectra and elemental analysis. The DTC agent chelating with Fe2+ produced a network polymer matrix, which captured and removed oil droplets efficiently. Oil removal by the flocculent on simulated produced water with 0, 200, 500, 900 mg/L of partially hydrolyzed polyacrylamide (HPAM) was investigated for aspects of effectiveness of DTC (T403) dosage and concentrations of HPAM and Fe2+ ions in the wastewater. Results showed that HPAM had a negative influence on oil removal efficiency when DTC (T403) dosage was lower than 20 mg/L. However, residual oil concentrations in tested samples with different concentrations of HPAM all decreased below 10 mg/L when DTC (T403) dosage reached 30 mg/L. The concentration of Fe2+ in the initial wastewater had a slight effect on oil removal at the range of 2-12 mg/L. Results showed that Fe3+ could not be used in place of Fe2+ as Fe3+ could not react with DTC under flocculated conditions. The effects of mineral salts ions were also investigated.
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Composites of polyaniline nanofibers and molecularly imprinted polymers for recognition of nitroaromatic compounds.
Chemistry
PUBLISHED: 04-06-2011
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This paper reports a monomer strategy for imprinting of 1,3-dinitrobenzene (DNB) molecules at the surface of conductive functional polyaniline nanofibers (PANI) for the first time. It has been demonstrated that the vinyl functional monomer layer on the PANI surface can not only direct the selective occurrence of imprinting polymerization, but can also drive DNB templates into the polymer through charge-transfer complexing interactions between DNB and functionalized PANI. These two basic processes lead to the formation of DNB-imprinted polymers at the surface of polyaniline nanofibers. The capacity to uptake DNB shows that selectivity coefficient in the nanofibers polymers is nearly three times as high as that of traditional imprinted materials and the nanofibers polymers also possess high selectivity toward DNB in comparison to similar nitroaromatic compounds. A linear response of DNB concentration between 2.20×10(-8) and 3.08×10(-6) M was exhibited with a detection limit of 7.33×10(-9) M (S/N=3). These results reported here could form the basis of a new strategy for preparing various polymer-coating layers on polyaniline supports and the molecular imprinting techniques discussed could also find applications in the fields of separation, trace detection, and environmental monitoring.
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Preparation of ceramic-corrosion-cell fillers and application for cyclohexanone industry wastewater treatment in electrobath reactor.
J. Hazard. Mater.
PUBLISHED: 03-20-2011
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As new media, ceramic-corrosion-cell fillers (Cathode Ceramic-corrosion-cell Fillers - CCF, and Anode Ceramic-corrosion-cell Fillers - ACF) employed in electrobath were investigated for cyclohexanone industry wastewater treatment. 60.0 wt% of dried sewage sludge and 40.0 wt% of clay, 40.0 wt% of scrap iron and 60.0 wt% of clay were utilized as raw materials for the preparation of raw CCF and ACF, respectively. The raw CCF and ACF were respectively sintered at 400°C for 20 min in anoxic conditions. The physical properties (bulk density, grain density and water absorption), structural and morphological characters and toxic metal leaching contents were tested. The influences of pH, hydraulic retention time (HRT) and the media height on removal of COD(Cr) and cyclohexanone were studied. The results showed that the bulk density and grain density of CCF and ACF were 869.0 kg m(-3) and 936.3 kg m(-3), 1245.0 kg m(-3) and 1420.0 kg m(-3), respectively. The contents of toxic metal (Cu, Zn, Cd, Pb, Cr, Ba, Ni and As) were all below the detection limit. When pH of 3-4, HRT of 6h and the media height of 60 cm were applied, about 90% of COD(cr) and cyclohexanone were removed.
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Synergy of the antiretroviral protease inhibitor indinavir and chloroquine against malaria parasites in vitro and in vivo.
Parasitol. Res.
PUBLISHED: 03-04-2011
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Many malaria-endemic areas are also associated with high rates of human immunodeficiency virus (HIV) infection. An understanding of the chemotherapeutic interactions that occur during malaria and HIV co-infections is important. Our previous studies have demonstrated that some antiretroviral protease inhibitors are effective in inhibiting Plasmodium falciparum growth in vitro. Currently, studies examining the interactions between antiretroviral protease inhibitors and antimalarial drugs are being conducted, but the data are limited. In this study, we examined the synergistic interactions between the antiretroviral protease inhibitor indinavir and chloroquine (CQ) in chloroquine-resistant and chloroquine-sensitive malaria parasites in vitro and in vivo. In vitro, by using modified fixed-ratio isobologram method, fractional inhibitory concentrations index (FICI) was calculated to indicate the interaction between the two drugs. The results demonstrated that indinavir interacted synergistically with chloroquine against both chloroquine-sensitive P. falciparum clone 3D7 (mean FICI 0.784) and multidrug-resistant P. falciparum clone Dd2 (mean FICI 0.599). In vivo drug interactions were measured using a 4-day suppressive test in a rodent malaria model infected with Plasmodium chabaudi. We observed that indinavir enhanced the antimalarial activity of chloroquine against both the chloroquine-sensitive line P. chabaudi ASS and the chloroquine-resistant line P. chabaudi ASCQ. More importantly, chloroquine had a 100% clearance of asexual parasites when used in combination with indinavir at an appropriate dose ratio (10 mg/kg CQ + 1.8 g/kg indinavir) where there was no obvious toxicity. We conclude from this study that the combination of indinavir and chloroquine may become a novel antimalarial drug regimen.
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Molecular docking study investigating the possible mode of binding of C.I. Acid Red 73 with DNA.
Int. J. Biol. Macromol.
PUBLISHED: 02-10-2011
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C.I. Acid Red 73 is a reactive azo dye with a variable potential carcinogenicity. The mechanism mediating interactions that occur between the dye and DNA have not been completely understood thus far. In this study, molecular docking techniques were applied to describe the most probable mode of DNA binding as well as the sequence selectivity of the C.I. Acid Red 73 dye. These docking experiments revealed that the dye is capable of interacting with the minor groove of the DNA on the basis of its curved shape, which fits well with the topology of double-stranded DNA. In addition, the dye can bind selectively to the minor groove of the DNA by applying CGT sequence selectivity. Further, the minor groove can be recognized although DNA targets present intercalation gaps. However, intercalative binding can also occur when the DNA target possesses an appropriate intercalation gap. Compared with the other eight DNA sequences that were studied, the DNA dodecamer d(CGCGATATCGCG)(2) (PDB ID: 1DNE) presents a very favorable target for the binding of C.I. Acid Red 73 to the minor groove, with the lowest binding free energy -9.19 kcal/mol. Results reported from this study are expected to provide useful information for research involving further simulations of molecular dynamics and toxicology investigations of the dye.
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Effect of OH-/Al3+ and Si/Al molar ratios on the coagulation performance and residual Al speciation during surface water treatment with poly-aluminum-silicate-chloride (PASiC).
J. Hazard. Mater.
PUBLISHED: 02-09-2011
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Coagulation performance, mechanism of poly-aluminum-silicate-chloride (PASiC) and residual Al speciation in the effluent with respect to a specific surface water treatment in China were comprehensively investigated in this study. The impact of OH(-)/Al(3+) and Si/Al molar ratios on the coagulation performance, mechanism and residual Al speciation of PASiC in surface water treatment was discussed as a function of coagulant dosage. It was intended to provide an insight into the relationship between coagulation performance and residual Al. Experimental results revealed that when OH(-)/Al(3+) molar ratio = 2.00 and Si/Al molar ratio = 0.0500 in PASiC coagulant, PASiC exhibited beneficial coagulation property and relatively lower content of residual Al. Surface bridging and entrapment was more effective compared with charge neutralization during the specific surface water treatment. The majority of residual Al in the effluent existed in the form of insoluble suspended or particulate Al. Dissolved organically bound Al was almost the major speciation in dissolved Al and dissolved inorganically bound monomeric Al was the only component in dissolved monomeric Al. Al in PASiC remained abundant at lower dosages and residual Al concentration could be effectively reduced at the dosages of 12.0-15.0mg/L as Al.
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Effect of aging period on the characteristics and coagulation behavior of polyferric chloride and polyferric chloride-polyamine composite coagulant for synthetic dying wastewater treatment.
J. Hazard. Mater.
PUBLISHED: 01-12-2011
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In this paper, a new composite inorganic-organic coagulant (PFC-EPI-DMA) was prepared by polyferric chloride (PFC) and epichlorohydrin-dimethylamine (EPI-DMA) under a given EPI-DMA/Fe and OH/Fe molar ratio. In comparison with PFC, the Fe (III) species and zeta potential of PFC-EPI-DMA were measured. Then their coagulation performance and coagulation kinetics for treating synthetic reactive dying wastewater were investigated. The results showed that the content of Fe(a) and Fe(b) in PFC-EPI-DMA and PFC coagulants decreased with increasing aging period. Compared to PFC, PFC-EPI-DMA had higher content of Fe(a) but lower content of Fe(b) and Fe(c). The zeta potentials of two coagulants decreased with increasing aging period within all tested pH range. For the treatment of reactive red 24, the color removal efficiency treated by PFC-EPI-DMA decreased, while that treated by PFC remained almost constant with increasing aging period. However, the color removal efficiencies of reactive blue 14 treated by two coagulants both decreased with increasing aging period. The results of floc aggregation process confirmed that with increasing aging period, the orders of floc growth rate, ratio and TWV treated by two coagulants were complicated.
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Effect of viscosity, basicity and organic content of composite flocculant on the decolorization performance and mechanism for reactive dyeing wastewater.
J Environ Sci (China)
PUBLISHED: 01-01-2011
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A coagulation/flocculation process using the composite flocculant polyaluminum chloride-epichlorohydrin dimethylamine (PAC-EPI-DMA) was employed for the treatment of an anionic azo dye (Reactive Brilliant Red K-2BP dye). The effect of viscosity (eta), basicity (B = [OH]/[Al]) and organic content (W(P)) on the flocculation performance as well as the mechanism of PAC-EPI-DMA flocculant were investigated. The eta was the key factor affecting the dye removal efficiency of PAC-EPI-DMA. PAC-EPI-DMA with an intermediate eta (2400 mPa x sec) gave higher decolorization efficiency by adsorption bridging and charge neutralization due to the co-effect of PAC and EPI-DMA polymers. The W(P) of the composite flocculant was a minor important factor for the flocculation. The adsorption bridging of PAC-EPI-DMA with eta of 300 or 4300 mPa x sec played an important role with the increase of W(P), whereas the charge neutralization of them was weaker with the increase of W(P). There was interaction between W(P) and B on the removal of reactive dye. The composite flocculant with intermediate viscosity and organic content was effective for the treatment of reactive dyeing wastewater, which could achieve high reactive dye removal efficiency with low organic dosage.
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Sorption of phosphate onto giant reed based adsorbent: FTIR, Raman spectrum analysis and dynamic sorption/desorption properties in filter bed.
Bioresour. Technol.
PUBLISHED: 09-02-2010
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A sorption process for the removal of phosphate was evaluated under various conditions using a filter bed packed with giant reed (GR) based adsorbent. FTIR spectrum measurement validated the existence of grafted amine groups in the adsorbent and Raman spectrum displayed the characteristic peaks of different forms of phosphate. The column sorption capacity of the adsorbent for phosphate was 54.67 mg g(-1) in comparison with the raw GR of 0.863 mg g(-1). Influent pH demonstrated an essential effect on the performance of the filter bed as compared to other influent conditions (flow rates and influent concentrations) and the optimal pH was selected at 5.0-10.0. Eluents of HCl, NaOH and NaCl solutions with concentrations of 0.01-0.1 mol l(-1) showed the excellent capacities for desorption of phosphate from the adsorbent, and their elution processes could be finished in 90 min.
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Synthesis and characterization of a novel super-absorbent based on wheat straw.
Bioresour. Technol.
PUBLISHED: 08-06-2010
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In order to develop an eco-friendly polymer, a novel super-absorbent polymer was prepared by graft copolymerization of acrylic acid (AA), acrylic amide (AM) and dimethyl diallyl ammonium chloride (DMDAAC) onto the pretreatment wheat straw (PTWS). The molecular structure of the super-absorbent was confirmed by FTIR. The factors that can influence absorbencies of the super-absorbent resin (SAR) were investigated, such as weight ratio between the monomers, the ratio of PTWS to monomers, the amount of initiator and cross-linker, temperature reaction time and neutralization degree of AA. The SAR has the water absorbency of 133.76 g/g in distilled water and 33.83 g/g in 0.9 wt.% NaCl solution.
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Preparation of ultra-lightweight sludge ceramics (ULSC) and application for pharmaceutical advanced wastewater treatment in a biological aerobic filter (BAF).
Bioresour. Technol.
PUBLISHED: 07-30-2010
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Novel media-ultra-lightweight sludge ceramics (ULSC) employed in an upflow lab-scale biological aerobic filter (BAF) were investigated for pharmaceutical advanced wastewater treatment. The influences of the volume ratio of pharmaceutical wastewater to domestic wastewater (PW/DW), hydraulic retention time (HRT) and air-liquid ratio (A/L) on chemical oxygen demand (CODCr) and ammonium (NH(4)(+)-N) of the effluent were investigated. When PW/DW of 4:1, HRT of 6 h, and A/L of 5:1 were applied, the mean effluent concentration of NH(4)(+)-N was 6.2 mg L(-1), and the maximum CODCr concentration in the effluent was 96 mg L(-1). Both NH(4)(+)-N and CODCr did not exceed the limits of the national discharge standards (NH(4)(+)-N ? 15 mg L(-1), CODCr ? 100 mg L(-1)). In addition, the BAF system showed a strong capacity of further removal from NH(4)(+)-N of the effluent.
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Equilibrium and a two-stage batch adsorber design for reactive or disperse dye removal to minimize adsorbent amount.
Bioresour. Technol.
PUBLISHED: 07-26-2010
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The adsorption of a reactive dye (Reactive Yellow K-4G) and a disperse dye (Disperse yellow brown S-2RFL) onto polyepicholorohydrin-dimethylamine (EPIDMA) cationic polymer modified bentonite (EPIDMA-bentonite) in batch adsorber was studied, respectively. Two equilibrium models, the Langmuir and Freundlich models were selected to follow the adsorption process. It was shown that the equilibrium experimental data for reactive dye adsorption could be well described by the Freundlich model, but for disperse dye the Langmuir model could be better. Based on the well correlated adsorption isotherm, an adsorption process design model was developed for the design of a two-stage batch adsorber to predict the minimum amount of adsorbent to achieve a specified percentage of dye removal at a given volume of wastewater effluents. The adsorption process design analysis indicated that compared with the single-stage batch adsorption, the two-stage process could significantly save adsorbent to meet the higher demands of dye removal efficiency.
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Transcriptome and targetome analysis in MIR155 expressing cells using RNA-seq.
RNA
PUBLISHED: 06-28-2010
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Previous studies have demonstrated the utility of microarray expression analysis to identify potential microRNA targets. Nevertheless, technical limitations intrinsic to this platform constrain its ability to fully exploit the potential of assessing transcript level changes to explore microRNA targetomes. High-throughput multiplexed Illumina-based next-generation sequencing (NGS) provides a digital readout of absolute transcript levels and imparts a higher level of accuracy and dynamic range than microarray platforms. We used Illumina NGS to analyze transcriptome changes induced by the human microRNA MIR155. This analysis resulted in a larger inferred targetome than similar studies carried out using microarray platforms. A comparison with 3 UTR reporter data demonstrated general concordance between NGS and corresponding 3 UTR reporter results. Nonharmonious results were investigated more deeply using transcript structure information assembled from the NGS data. This analysis revealed that transcript structure plays a substantial role in mitigated targeting and in frank targeting failures. With its high level of accuracy, its broad dynamic range, its utility in assessing transcript structure, and its capacity to accurately interrogate global direct and indirect transcriptome changes, NGS is a useful tool for investigating the biology and mechanisms of action of microRNAs.
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Removal natural organic matter by coagulation-adsorption and evaluating the serial effect through a chlorine decay model.
J. Hazard. Mater.
PUBLISHED: 06-04-2010
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The removal of natural organic matter (NOM) by coagulation and adsorption on modified wheat straw (MWS) was investigated. Two types of inorganic polymer coagulants, polyferric chloride (PFC) and polyaluminum chloride (PAC), were used during experiments. The removal efficiency of NOM in terms of UV(254), DOC and COD(Mn) increased with the dosage of coagulants and adsorbent increasing. Combined coagulation and adsorption showed better UV(254) and turbidity removal efficiency (61.8% and 95.8% respectively for PFC-MWS, and 61.5% and 94.2% respectively for PAC-MWS) than individual treatment. The effects of combination sequences on DOC fractionation and residual chlorine decay were analyzed and the chlorine data were fitted using a chlorine decay model. In general, the higher the molecular weight of NOM was, the better removal efficiency the combined treatment can achieve. MWS can enhance the removal of NOM with higher molecular weight. The disinfection by-products (DBPs) formation potential in the effluents from coagulation and subsequent adsorption was greater than that in the effluents from adsorption and subsequent coagulation.
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Differential expression of the miR-200 family microRNAs in epithelial and B cells and regulation of Epstein-Barr virus reactivation by the miR-200 family member miR-429.
J. Virol.
PUBLISHED: 05-19-2010
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The miR-200 microRNA family is important for maintaining the epithelial phenotype, partially through suppressing ZEB1 and ZEB2. Since ZEB1 inhibits Epstein-Barr virus (EBV) reactivation, we hypothesized that expression of miR-200 family members in epithelial cells may partly account for higher levels of EBV reactivation in this tissue (relative to nonplasma B cells). Here we show that, whereas miR-200 family members are expressed in epithelial cells, their expression is low in latently infected B cells. Furthermore, the miR-200 family member miR-429 shows elevated expression in plasma cell lines and is induced by B-cell-receptor activation in Akata cells. Lastly, expression of miR-429 can break latency.
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Chiral separation of neonicotinoid insecticides by polysaccharide-type stationary phases using high-performance liquid chromatography and supercritical fluid chromatography.
Chirality
PUBLISHED: 05-03-2010
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The enantiomeric separations of three neonicotinoid insecticides (identified as compounds 1, 2, and 3) were performed on three polysaccharide-type chiral columns, that is, Chiralcel OD-H, Chiralpak AD-H, and Chiralpak IB, by high-performance liquid chromatography (HPLC) and supercritical fluid chromatography (SFC). Effects of the modifier percentage and column temperature on chiral recognitions of chiral stationary phases were also studied. Both 1 and 2 could be resolved on all three columns selected, with the highest R(s) values obtained on Chiralpak AD-H and Chiralcel OD-H, respectively. However, satisfactory separation of the four stereoisomers of 3 was only achieved on Chiralcel OD-H. Considering the effects of ethanol on the values of k, ?, and R(s), we concluded that hydrogen bonding, ?-?, and/or dipole-dipole interactions might be all responsible for the chiral separation. In comparison to HPLC, a shorter run time was achieved for 1 and 2 by SFC. However, 3 could not be stereoselectively resolved using SFC. On the basis of the calculated thermodynamic parameters, we found that the separation processes of enantiomers of 1 and 2 were entropy controlled and enthalpy controlled, respectively.
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MicroRNA miR-155 inhibits bone morphogenetic protein (BMP) signaling and BMP-mediated Epstein-Barr virus reactivation.
J. Virol.
PUBLISHED: 04-28-2010
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MicroRNA miR-155 is expressed at elevated levels in human cancers including cancers of the lung, breast, colon, and a subset of lymphoid malignancies. In B cells, miR-155 is induced by the oncogenic latency gene expression program of the human herpesvirus Epstein-Barr virus (EBV). Two other oncogenic herpesviruses, Kaposis sarcoma-associated herpesvirus and Mareks disease virus, encode functional homologues of miR-155, suggesting a role for this microRNA in the biology and pathogenesis of these viruses. Bone morphogenetic protein (BMP) signaling is involved in an array of cellular processes, including differentiation, growth inhibition, and senescence, through context-dependent interactions with multiple signaling pathways. Alteration of this pathway contributes to a number of disease states including cancer. Here, we show that miR-155 targets the 3 untranslated region of multiple components of the BMP signaling cascade, including SMAD1, SMAD5, HIVEP2, CEBPB, RUNX2, and MYO10. Targeting of these mediators results in the inhibition of BMP2-, BMP6-, and BMP7-induced ID3 expression as well as BMP-mediated EBV reactivation in the EBV-positive B-cell line, Mutu I. Further, miR-155 inhibits SMAD1 and SMAD5 expression in the lung epithelial cell line A549, it inhibits BMP-mediated induction of the cyclin-dependent kinase inhibitor p21, and it reverses BMP-mediated cell growth inhibition. These results suggest a role for miR-155 in controlling BMP-mediated cellular processes, in regulating BMP-induced EBV reactivation, and in the inhibition of antitumor effects of BMP signaling in normal and virus-infected cells.
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The regeneration characteristics of various red mud granular adsorbents (RMGA) for phosphate removal using different desorption reagents.
J. Hazard. Mater.
PUBLISHED: 04-09-2010
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In this research, various red mud granular adsorbents (RMGA), which were made from red mud--a kind of waste residue from the alumina industry, were manufactured under different sintering temperatures (ST). For the purpose of investigating the regeneration characteristics of them for phosphate removal, systematic experiments were carried out, including adsorption, desorption (using different desorption reagents) and resorption tests. When RMGA were desorbed by HCl solutions, the desorption efficiencies were relatively higher due to acid erosion, but the corresponding resorption capacities became small owing to extraction of effective components. Although RMGA rarely released phosphate in desorption process when being desorbed by deionised water, it performed well on resorption of phosphate afterwards. It was assumed that the lower pH in resorption process, which was caused by the reductive release of CaO into solution, contributed to a weaker competition of OH(-) on phosphate resorption. When NaOH solution was employed as the desorption reagent, resorption capacities of RMGA were relatively larger and increased with the increase of NaOH concentration, because OH(-) might ameliorate the chemical composition on the surface of RMGA potentially. In addition, several RMGA manufactured under lower ST obtained larger resorption capacities than their original adsorption capacities, because of the comparatively unstable crystal structure which led to a stronger amelioration on them.
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Probing the molecular mechanism of C.I. Acid red 73 binding to human serum albumin.
Environ. Toxicol. Pharmacol.
PUBLISHED: 03-13-2010
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The molecular mechanism of C.I. Acid red 73 binding to human serum albumin (HSA) was investigated by spectroscopy and molecular docking procedures. The molecular docking results indicated that subdomain IB of HSA was the main active binding site for C.I. Acid red 73. The spectroscopic experiment results showed that the mechanism of the interaction between C.I. Acid red 73 and HSA was dominantly initiated by complex formation and the number of binding site (n) was 1.71 at 298K. The molecular docking study and thermodynamic analysis suggested that the forces acting was predominantly hydrophobic and hydrogen bond interactions. Far-UV circular dichroism (CD) spectroscopy also revealed that the conformation of the HSA changed slightly after C.I. Acid red 73 bound to the HSA. The mean distance between the bound dye and the Trp residue is 3.28nm as calculated from Förster energy transfer.
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Adsorption kinetics and desorption of Cu(II) and Zn(II) from aqueous solution onto humic acid.
J. Hazard. Mater.
PUBLISHED: 01-19-2010
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The adsorption kinetics of Cu(II) and Zn(II) from aqueous solution onto humic acid (HA) were investigated under different conditions. The results showed that HA was particularly effective for adsorbing heavy metals and that the effective pH range was above 6. The adsorption force was not single and dependent on solution pH. The experimental data were found to comply with the pseudo-second-order kinetic model with adsorption capacity, q(e cal) more close to the measured results. Increment of initial adsorbate concentration (1-4 mg/L) and temperature (283-303 K) are both favorable to adsorption process. Based on the desorption experiments, it is further indicated that the main adsorption force was complexation effect between organic ligands of HA surface and metal ions and the percentage of desorption is 50% for Cu and 30% for Zn, respectively.
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Equilibrium and kinetic adsorption study of the adsorptive removal of Cr(VI) using modified wheat residue.
J Colloid Interface Sci
PUBLISHED: 01-11-2010
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A new adsorbent modified from wheat residue was synthesized after reaction with epichlorohydrin and triethylamine by using the modifying agents of diethylenetriamine in the presence of organic medium of N,N-dimethylformamide. The performance of the modified wheat straw (MWS) was characterized by Fourier transform infrared spectroscopy and point of zero charge analysis. The adsorption was investigated in a batch adsorption system, including both equilibrium adsorption isotherms and kinetics. Results showed that MWR had great anion-adsorbing capacity, due to the existence of a large number of introduced amino groups, and the value of pH(PZC) was around 5.0. Equilibrium data were analyzed using the Langmuir, Freundlich, and Temkin isotherm models and were found to be best represented by the Freundlich isotherm model. Evaluation of the adsorption process identified its endothermic nature. The maximum adsorption capacity of MWS for the removal of Cr(VI) was 322.58mg/g at 328K, indicating that MWS has high chromium removal efficiency, compared to other adsorbents reported. The kinetics of adsorption followed the pseudo-second-order kinetic equation. The mechanism of adsorption was investigated using the intraparticle diffusion model. Thermodynamic parameters (free energy change, enthalpy change, and entropy change) revealed that the adsorption of Cr(VI) onto MWS was endothermic and spontaneous; additionally, the adsorption can be characterized as an ion-exchange process. The results suggest that MWS is an inexpensive and efficient adsorbent for removing Cr(VI) ions from aqueous solution.
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Effect of shear force and solution pH on flocs breakage and re-growth formed by nano-Al(13) polymer.
Water Res.
PUBLISHED: 09-12-2009
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The breakage and re-growth of flocs formed by polyaluminum chloride (PAC) and the Al(13)O(4) (OH)(24)(7+) (Al(13) for short) polymer were comparatively evaluated for the coagulation of humic acid (HA). A series of jar experiments were conducted to investigate the impacts of shear rate and solution pH on flocs breakage and re-aggregation potential. Results indicated that the responses of flocs to the increasing shear force and solution pH depend on the coagulant used. The ability of flocs to resist breakage decreased with the increasing shear rate. For all levels of shear force investigated in this study, the flocs formed by Al(13) polymer were weaker than those of PAC, whereas Al(13) polymer displayed a better recoverability than PAC. The similar results were obtained when pH of solution was changed. The flocs generated in acidic conditions were stronger and more recoverable than those generated in alkaline conditions no matter which coagulant was used.
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Flocculation performance of epichlorohydrin-dimethylamine polyamine in treating dyeing wastewater.
J. Environ. Manage.
PUBLISHED: 08-17-2009
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Epichlorohydrin-dimethylamine polymers with different intrinsic viscosity (eta) and cationicity (tau) were synthesized. The flocculation performance and mechanism of these polymers in the removal of the reactive and disperse dyes from synthetic wastewater was investigated in terms of flocculation dynamics and color removal efficiency. The polymer flocculation efficiency was compared with that of polyaluminum chloride (PAC) and a composite flocculant based on polyaluminum chloride-epichlorohydrin-dimethylamine polyamine. The results showed that epichlorohydrin-dimethylamine polymer was effective over a pH range of 2-10 for the reactive and disperse dye removal (Reactive Brilliant Red and Disperse Yellow dyes). Epichlorohydrin-dimethylamine polymer with the highest eta and tau gave the best reactive dye removal efficiency, and its adsorption-bridging and electric neutralization ability played important roles in the flocculation process. The higher the eta viscosity of the epichlorohydrin-dimethylamine polymer, the better the flocculation performance of epichlorohydrin-dimethylamine polyamine, and stronger adsorption-bridging ability was obtained for removing the disperse dye from dyeing wastewaters. Epichlorohydrin-dimethylamine polymer achieved better decolorization performance when used together with PAC.
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The coordination of the tetraselenidoantimonate [SbSe4]3- anion with trivalent lanthanide ions tuned by ethylene polyamines.
Inorg Chem
PUBLISHED: 08-12-2009
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The solvothermal synthetic system Ln/Sb/Se (Ln = La, Eu) was investigated in different ethylene polyamines, and a series of lanthanum and europium selenidoantimonates [La(en)(2)(dien)(eta(2)-SbSe(4))] (Ia), [La(dien)(2)(mu-eta(1),eta(2)-SbSe(4))] (Ib), [La(trien)(2)(H(2)O)]SbSe(4) (Ic), [La(en)(trien)(mu-eta(1),eta(2)-SbSe(4))] (Id), [Eu(en)(2)(dien)(SbSe(4))] (IIa), [Eu(en)(trien)(eta(2)-SbSe(4))] (IIb), and [Eu(dien)(2)(eta(2)-SbSe(4))] (IIc) (en = ethylenediamine, dien = diethylenetriamine, trien = triethylenetetramine) were prepared. A systematic investigation of the crystal structures showed that the soft Lewis basic ligand [SbSe(4)](3-) can be tuned to coordinate to the hard Lewis acidic lanthanide ions as a monodentate ligand, mono-SbSe(4); a bidentate chelating ligand, eta(2)-SbSe(4); or a tridentate bridging ligand, mu-eta(1),eta(2)-SbSe(4), by the ethylene polyamines or mixed ethylene polyamines used in the syntheses. The [SbSe(4)](3-) anion exhibited different coordination modes for La(3+) and Eu(3+) ions in the presence of the same ethylene polyamine because of the different coordination numbers of La(3+) and Eu(3+) ions.
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Research on the characteristics of red mud granular adsorbents (RMGA) for phosphate removal.
J. Hazard. Mater.
PUBLISHED: 08-11-2009
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Red mud (RM), a waste tailing from alumina industry, was employed with bentonite and starch as the main raw materials for producing granular adsorbents in this study. The important parameters, which greatly affect the characteristics of red mud granular adsorbents (RMGA), such as the mass ratio of three raw materials, preheating time, preheating temperature, sintering time and sintering temperature (ST), were investigated. Adsorption capacities for various RMGA were described in terms of removal of phosphate from aqueous solution according to the adsorption experiments, in which certain operation parameters (like stirring speed, reaction time, adsorbent dosage, initial pH and initial phosphate concentration) at three different aquatic temperatures (AT) were applied. The results showed that the optimum ST, under which the largest adsorption capacity was achieved for RMGA with certain RM ratio, varied with different AT in adsorption process. Based on the further characterizations of RMGA, it was speculated that the performance above was caused by the competitive interactions of chemical adsorption and physical adsorption on RMGA, since the increase in ST could lead to qualitative diversification on the surface and quantitative decrease of effective components for adsorption simultaneously.
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Effect of sludge-fly ash ceramic particles (SFCP) on synthetic wastewater treatment in an A/O combined biological aerated filter.
Bioresour. Technol.
PUBLISHED: 08-11-2009
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Novel media-sludge-fly ash ceramic particles (SFCP) employed in an upflow lab-scale A/O BAF were investigated for synthetic wastewater treatment. The influences of hydraulic retention time (HRT), air-liquid ratio (A/L) and recirculation on the removals of chemical oxygen demand (CODcr), ammonia (NH(4)(+)-N) and total nitrogen (TN) were discussed. The optimum operation conditions were obtained as HRT of 2.0 h, A/L of 15:1 and 200% recirculation. Under the optimal conditions, 90% CODcr, more than 98% NH(3)-N and approximately 70% TN were removed. The average consumed volumetric loading rates for CODcr, NH(4)(+)-N and TN with 200% recirculation were 4.06, 0.36 and 0.29 kg(m(3)d)(-1), respectively. The CODcr and TN removal mainly occurred in the anoxic zone, while nitrification was completed at the height of 70 cm from the inlet of the bottom due to a suitable column layout of biological aerated filter (BAF). The characteristics of wastewater and backwashing affected TN removal to a large degree. In addition, the features of media (SFCP) and synthetic wastewater contributed to a strong buffer capacity in the BAF system so that the effluent pH at different media height fluctuated slightly and was insensitive to recirculation.
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Preparation and mechanism of ultra-lightweight ceramics produced from sewage sludge.
J. Hazard. Mater.
PUBLISHED: 07-15-2009
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The preparation, characterization, preheating mechanism and bloating mechanism of ultra-lightweight ceramics (ULWC) manufactured by dehydrated sewage sludge (DSS) and clay were studied. Three experiments were designed to investigate the addition of DSS, the effect of preheating treatment and sintering treatment, respectively, and then the optimum conditions for preparing ULWC were determined. Chemical components, especially ratios of carbon content to iron oxide content (C/Fe-ratios), were used to explain the preheating mechanism; physical forces (surface tension and bloating force) combined with C/Fe-ratios were used to explain the bloating mechanism. The characterizations (physical properties, microstructure properties and toxic metal leaching properties) of ULWC that were prepared under the optimum conditions were tested. The results showed that the optimum addition of DSS was 20-30 wt.%, and the pellets which preheated at 400 degrees C for 20 min and sintered at 1150 degrees C for 10 min were beneficial to produce ULWC. Property tests of ULWC showed that ULWC was light (with a bulk density of 330.80 kg m(-3)), waterproof (with a water absorption of 5.30 wt.%), nontoxic (contents of toxic metal leaching test were all below the detection limit) and suitable for practical civil engineering.
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Determination of parathion in vegetables by electrochemical sensor based on molecularly imprinted polyethyleneimine/silica gel films.
J. Agric. Food Chem.
PUBLISHED: 07-10-2009
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A novel sensor for the determination of parathion based on coupled grafting of the functional macromolecule polyethyleneimine on surfaces of silica gel particles via a surface imprinting method using molecular imprinting technology was fabricated. The electrochemical behavior of parathion at the imprinted sensor was characterized by cyclic voltammetry and linear sweeping voltammetry. The imprinted films showed high selectivity toward parathion in comparison to similar organophosphates. A linear response over parathion concentration in the range of 0.015-15 mg kg(-1) was exhibited with a detection limit of 0.003 mg kg(-1) (S/N = 3). The imprinted film sensor has been applied to the determination of parathion in spiked vegetable samples and shows promise for fast and selective determination of trace levels of parathion in real samples.
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In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.