415 research outputs found

    Surfactant Removal on Waste Water

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    Surfactants are among the most widespread pollutants that contribute significantly to the pollution profile of sewage and wastewater of all kinds. There are various methods of performing surfactant removal from wastewater, however, most of these methods are not economically feasible and consume a large amount of energy. This project investigates the method of surfactant removal using froth flotation. This method has proved to be comparatively economical and consumes less energy. It is a much simpler process and the equipment used are not complicated. The effects of various parameters such as flotation time, surfactant concentration and air flow rate were investigated. The optimum air flow rate value and flotation time will be determined for effective froth generation

    Surfactant Removal on Waste Water

    Get PDF
    Surfactants are among the most widespread pollutants that contribute significantly to the pollution profile of sewage and wastewater of all kinds. There are various methods of performing surfactant removal from wastewater, however, most of these methods are not economically feasible and consume a large amount of energy. This project investigates the method of surfactant removal using froth flotation. This method has proved to be comparatively economical and consumes less energy. It is a much simpler process and the equipment used are not complicated. The effects of various parameters such as flotation time, surfactant concentration and air flow rate were investigated. The optimum air flow rate value and flotation time will be determined for effective froth generation

    Efficient production of pullulan by Aureobasidium pullulans grown on mixtures of potato starch hydrolysate and sucrose

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    AbstractPullulan is a natural exopolysaccharide with many useful characteristics. However, pullulan is more costly than other exopolysaccharides, which limits its effective application. The purpose of this study was to adopt a novel mixed-sugar strategy for maximizing pullulan production, mainly using potato starch hydrolysate as a low-cost substrate for liquid-state fermentation by Aureobasidium pullulans. Based on fermentation kinetics evaluation of pullulan production by A. pullulans 201253, the pullulan production rate of A. pullulans with mixtures of potato starch hydrolysate and sucrose (potato starch hydrolysate:sucrose=80:20) was 0.212h−1, which was significantly higher than those of potato starch hydrolysate alone (0.146h−1) and mixtures of potato starch hydrolysate, glucose, and fructose (potato starch hydrolysate:glucose:fructose=80:10:10, 0.166h−1) with 100gL−1 total carbon source. The results suggest that mixtures of potato starch hydrolysate and sucrose could promote pullulan synthesis and possibly that a small amount of sucrose stimulated the enzyme responsible for pullulan synthesis and promoted effective potato starch hydrolysate conversion effectively. Thus, mixed sugars in potato starch hydrolysate and sucrose fermentation might be a promising alternative for the economical production of pullulan

    Self‐organization of ionic liquid‐modified organosilica hollow nanospheres and heteropolyacids: efficient preparation of 5‐HMF under mild conditions

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    As a biomass‐derived platform molecule, 5‐hydroxymethylfurfural (5‐HMF) is a highly desirable feedstock for manufacturing of high value‐added chemicals ranging from starting materials for polyesters to biofuels. In this work, we reported the fabrication of a series of multicomponent solid acid catalysts based on heteropolyacids immobilized ILs‐modified organosilica hollow nanospheres (denoted as PW12‐ILs‐Cn‐HNS), in which PW12 (PW12=H3PW12O40 ⋅ xH2O) provides Brønsted acid site, ILs show strong electrostatic interactions with PW12, Cn (Cn=alkyl chain) is attached for hydrophobicity and HNS represents organosilica hollow nanospheres. When applied for catalytic dehydration of fructose to 5‐HMF, the PW12‐ILs‐C4‐HNS catalyst with 15.2 % PW12 loading exhibited the best dehydration activity to 5‐HMF with 93.7 % yield in DMSO at 100 °C in 2 h. Compared with 2D hexagonal and 3D interconnected structures, the excellent porosity properties of hollow nanospherical structure can provide a high population of the PW12 sites and enough confined nanospace for the dehydration of fructose. Moreover, the PW12‐ILs‐Cn‐HNS catalyst showed excellent stability over six catalytic cycles without obvious loss of activity. Most importantly, careful identification of the observed intermediates revealed crucial information for the dehydration process of fructose to 5‐HMF. As such, the proposed heterogeneous catalysts show great potential in biomass conversion processes

    Spectroscopy of momentum state lattices

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    We explore a technique for probing energy spectra in synthetic lattices that is analogous to scanning tunneling microscopy. Using one-dimensional synthetic lattices of coupled atomic momentum states, we explore this spectroscopic technique and observe qualitative agreement between the measured and simulated energy spectra for small two- and three-site lattices as well as a uniform many-site lattice. Finally, through simulations, we show that this technique should allow for the exploration of the topological bands and the fractal energy spectrum of the Hofstadter model as realized in synthetic lattices.Comment: 9 pages, 5 figure

    Decision ambiguity is mediated by a late positive potential originating from cingulate cortex

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    People often make decisions in the face of ambiguous information, but it remains unclear how ambiguity is represented in the brain. We used three types of ambiguous stimuli and combined EEG and fMRI to examine the neural representation of perceptual decisions under ambiguity. We identified a late positive potential, the LPP, which differentiated levels of ambiguity, and which was specifically associated with behavioral judgments about choices that were ambiguous, rather than passive perception of ambiguous stimuli. Mediation analyses together with two further control experiments confirmed that the LPP was generated only when decisions are made (not during mere perception of ambiguous stimuli), and only when those decisions involved choices on a dimension that is ambiguous. A further control experiment showed that a stronger LPP arose in the presence of ambiguous stimuli compared to when only unambiguous stimuli were present. Source modeling suggested that the LPP originated from multiple loci in cingulate cortex, a finding we further confirmed using fMRI and fMRI-guided ERP source prediction. Taken together, our findings argue for a role of an LPP originating from cingulate cortex in encoding decisions based on task-relevant perceptual ambiguity, a process that may in turn influence confidence judgment, response conflict, and error correction

    Vesiclepedia 2019 : a compendium of RNA, proteins, lipids and metabolites in extracellular vesicles

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    Extracellular vesicles (EVs) are membranous vesicles that are released by both prokaryotic and eukaryotic cells into the extracellular microenvironment. EVs can be categorised as exosomes, ectosomes or shedding microvesicles and apoptotic bodies based on the mode of biogenesis. EVs contain biologically active cargo of nucleic acids, proteins, lipids and metabolites that can be altered based on the precise state of the cell. Vesiclepedia (http://www.microvesicles.org) is a web-based compendium of RNA, proteins, lipids and metabolites that are identified in EVs from both published and unpublished studies. Currently, Vesiclepedia contains data obtained from 1254 EV studies, 38 146 RNA entries, 349 988 protein entries and 639 lipid/metabolite entries. Vesiclepedia is publicly available and allows users to query and download EV cargo based on different search criteria. The mode of EV isolation and characterization, the biophysical and molecular properties and EV-METRIC are listed in the database aiding biomedical scientists in assessing the quality of the EV preparation and the corresponding data obtained. In addition, FunRich-based Vesiclepedia plugin is incorporated aiding users in data analysis

    Hydroxysafflor Yellow A protects spinal cords from ischemia/reperfusion injury in rabbits

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    <p>Abstract</p> <p>Background</p> <p>Hydroxysafflor Yellow A (HSYA), which is one of the most important active ingredients of the Chinese herb <it>Carthamus tinctorius L</it>, is widely used in the treatment of cerebrovascular and cardiovascular diseases. However, the potential protective effect of HSYA in spinal cord ischemia/reperfusion (I/R) injury is still unknown.</p> <p>Methods</p> <p>Thirty-nine rabbits were randomly divided into three groups: sham group, I/R group and HSYA group. All animals were sacrificed after neurological evaluation with modified Tarlov criteria at the 48th hour after reperfusion, and the spinal cord segments (L4-6) were harvested for histopathological examination, biochemical analysis and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) staining.</p> <p>Results</p> <p>Neurological outcomes in HSYA group were slightly improved compared with those in I/R group. Histopathological analysis revealed that HSYA treatment attenuated I/R induced necrosis in spinal cords. Similarly, alleviated oxidative stress was indicated by decreased malondialdehyde (MDA) level and increased superoxide dismutase (SOD) activity after HSYA treatment. Moreover, as seen from TUNEL results, HSYA also protected neurons from I/R-induced apoptosis in rabbits.</p> <p>Conclusions</p> <p>These findings suggest that HSYA may protect spinal cords from I/R injury by alleviating oxidative stress and reducing neuronal apoptosis in rabbits.</p

    Heteropolyacids and sulfonic acid-bifunctionalized organosilica spheres for efficient manufacture of cellulose acetate propionate with high viscosity

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    Cellulose acetate propionate (CAP), a high value-added chemical, is traditionally prepared using H2SO4 as catalyst. Replacement of the mineral acids by solid acids is current research focus for green and sustainable production of CAP. Herein, we reported the fabrication of novel solid acid catalyst HPW/Si(Et)Si-Dim-SO3H (Si(Et)Si = ethyl-bridged organosilica and Dim = dihydroimidazole) by incorporating phosphotungstic acid (HPW) and sulfonic acid-based Brønsted acidic ionic liquids onto the organosilica nanospheres of the designed catalyst for efficient manufacture CAP via esterification. The results indicated that the as-prepared HPW/Si(Et)Si-Dim-SO3H with 7.5% HPW loading showed the best catalytic performance at 45 °C in 3 h and the resulting CAP exhibited viscosity of 447 mPa s, Mw of 102,882 and DS of 2.69. Most importantly, the HPW/Si(Et)Si-Dim-SO3H exhibited high catalytic stability over six consecutive cycles and the obtained products were stable too with similar DS, Mw and viscosity. As such, the designed heteropolyacids and sulfonic acid-bifunctionalized heterogeneous catalyst is highly promising for biomass conversion under mild conditions
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