5,547 research outputs found

    Enhancing sewage sludge anaerobic 're-digestion' with combinations of ultrasonic, ozone and alkaline treatments

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    This study investigated the feasibility of using ultrasonic (ULS), ozone assisted ultrasonic (ULS-Ozone) and alkaline assisted ultrasonic (ULS+ALK) post-treatment to target the persistent organic fraction in anaerobically digested sludge in order to increase methane recovery. Synergistic COD solubilization in digested sludge was observed when ozone (0.012 g O3 g-1 TS) and alkaline (0.02M for 10 min.) treatment was combined with ULS treatment. The digested sludge Soluble Chemical Oxygen Demand (SCOD) increased from 200 mg/L to 1,500, 2,600 and 2,650 mg/L after the ULS, ULS-Ozone and ULS+ALK treatments, respectively. Different compounds were, however, solubilized after the ULS-Ozone and ULS+ALK treatments as indicated by size exclusion chromatography (SEC). ULS+ALK treatment primarily solubilized macromolecules with molecular weight (MW) over 500 kDa; while, the ULS-Ozone treatment solubilized macromolecules with MW higher than 500 kDa and also organics with MW around 103 kDa. The methane production from “re-digestion” of the treated digested sludge increased by 28.3%, 48.3% and 39.5% after the ULS, ULS-Ozone and ULS+ALK treatments, respectively

    Transient Super-strong Coronal Lines and Broad Bumps in the Galaxy SDSS J074820.67+471214.3

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    Variable super-strong coronal emission lines were observed in one galaxy, SDSS J095209.56+214313.3, and their origin remains controversy. In this paper, we report the detection of variable broad spectral bumps, reminiscent of supernova (SN) II-Plateau (II-P) spectra taken a few days after the shock breakout, in the second galaxy with variable super-strong coronal lines, SDSS J074820.67+471214.3. The coronal line spectrum shows unprecedented high ionization with strong [Fe X], [Fe XI], [Fe XIV], [S XII] and [Ar XIV], but without detectable optical [Fe VII] lines. The coronal line luminosities are similar to that observed in bright Seyfert galaxies, and 20 times more luminous than that reported in the hottest Type IIn SN 2005ip. The coronal lines (σ 120−240\sigma ~120-240 km s-1) are much broader than the narrow lines (σ∌40\sigma \sim 40 km/s) from the star forming regions in the galaxy, but at nearly the same systematic redshift. We also detected a variable non-stellar continuum in optical and UV. In the follow-up spectra taken 4-5 years later, the coronal lines, SN-like feature, and non-stellar continuum disappeared, while the [O III] intensity increased by about a factor of ten. Our analysis suggests that the coronal line region should be at least ten light days in size, and be powered either by a quasi-steady ionizing source with a soft X-ray luminosity at least a few 10^{42} erg s-1 or by a very luminous soft X-ray outburst. These findings can be more naturally explained by a star tidally disrupted by the central black hole than by an SN explosion.Comment: 21 pages, 6 figures, accepted to Ap

    NMR Methods for Determining Lipid Turnover via Stable Isotope Resolved Metabolomics

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    Lipids comprise diverse classes of compounds that are important for the structure and properties of membranes, as high-energy fuel sources and as signaling molecules. Therefore, the turnover rates of these varied classes of lipids are fundamental to cellular function. However, their enormous chemical diversity and dynamic range in cells makes detailed analysis very complex. Furthermore, although stable isotope tracers enable the determination of synthesis and degradation of complex lipids, the numbers of distinguishable molecules increase enormously, which exacerbates the problem. Although LC-MS-MS (Liquid Chromatography-Tandem Mass Spectrometry) is the standard for lipidomics, NMR can add value in global lipid analysis and isotopomer distributions of intact lipids. Here, we describe new developments in NMR analysis for assessing global lipid content and isotopic enrichment of mixtures of complex lipids for two cell lines (PC3 and UMUC3) using both 13C6 glucose and 13C5 glutamine tracers

    Characterization and biodegradability of sludge from a high rate A-stage contact tank and B-stage membrane bioreactor of pilot-scale AB system treating municipal wastewaters

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    In light of global warming mitigation efforts, increasing sludge disposal costs, and need for reduction in the carbon footprint of wastewater treatment plants, innovation in treatment technology has been tailored towards energy self-sufficiency. The AB process is a promising technology for achieving maximal energy recovery from wastewaters with minimum energy expenditure and therefore inherently reducing excess sludge production. Characterization of this novel sludge and its comparison with the more conventional B-stage sludge are necessary for a deeper understanding of AB treatment process design. This paper presents a case study of a pilot-scale AB system treating municipal wastewaters as well as a bio- (biochemical methane potential and adenosine tri-phosphate analysis) and physico-chemical properties (chemical oxygen demand, sludge volume index, dewaterability, calorific value, zeta potential and particle size distribution) comparison of the organic-rich A-stage against the B-stage activated sludge. Compared to the B-sludge, the A-sludge yielded 1.4 to 4.9 times more methane throughout the 62-week operation

    Engineered Microenvironment for Manufacturing Human Pluripotent Stem Cell-Derived Vascular Smooth Muscle Cells

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    Human pluripotent stem cell-derived vascular smooth muscle cells (hPSC-VSMCs) are of great value for disease modeling, drug screening, cell therapies, and tissue engineering. However, producing a high quantity of hPSC-VSMCs with current cell culture technologies remains very challenging. Here, we report a scalable method for manufacturing hPSC-VSMCs in alginate hydrogel microtubes (i.e., AlgTubes), which protect cells from hydrodynamic stresses and limit cell mass to \u3c400 \u3eÎŒm ensure efficient mass transport. The tubes provide cells a friendly microenvironment, leading to extremely high culture efficiency.We have shown that hPSC-VSMCs can be generated in 10 days with high viability, high purity, and high yield (~5.0 x 108 cells/mL). Phenotype and gene expression showed that VSMCs made in AlgTubes and VSMCs made in 2D cultures were similar overall. However, AlgTube-VSMCs had higher expression of genes related to vasculature development and angiogenesis, and 2D-VSMCs had higher expression of genes related to cell death and biosynthetic processes

    A Previously Uncharacterized, Nonphotosynthetic Member of the Chromatiaceae Is the Primary CO_2-Fixing Constituent in a Self-Regenerating Biocathode

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    Biocathode extracellular electron transfer (EET) may be exploited for biotechnology applications, including microbially mediated O_2 reduction in microbial fuel cells and microbial electrosynthesis. However, biocathode mechanistic studies needed to improve or engineer functionality have been limited to a few select species that form sparse, homogeneous biofilms characterized by little or no growth. Attempts to cultivate isolates from biocathode environmental enrichments often fail due to a lack of some advantage provided by life in a consortium, highlighting the need to study and understand biocathode consortia in situ. Here, we present metagenomic and metaproteomic characterization of a previously described biocathode biofilm (+310 mV versus a standard hydrogen electrode [SHE]) enriched from seawater, reducing O_2, and presumably fixing CO_2 for biomass generation. Metagenomics identified 16 distinct cluster genomes, 15 of which could be assigned at the family or genus level and whose abundance was roughly divided between Alpha- and Gammaproteobacteria. A total of 644 proteins were identified from shotgun metaproteomics and have been deposited in the the ProteomeXchange with identifier PXD001045. Cluster genomes were used to assign the taxonomic identities of 599 proteins, with Marinobacter, Chromatiaceae, and Labrenzia the most represented. RubisCO and phosphoribulokinase, along with 9 other Calvin-Benson-Bassham cycle proteins, were identified from Chromatiaceae. In addition, proteins similar to those predicted for iron oxidation pathways of known iron-oxidizing bacteria were observed for Chromatiaceae. These findings represent the first description of putative EET and CO_2 fixation mechanisms for a self-regenerating, self-sustaining multispecies biocathode, providing potential targets for functional engineering, as well as new insights into biocathode EET pathways using proteomics

    Performance of A-stage process treating combined municipal-industrial wastewater

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    A biosorption column and a settling tank were operated for 6 months with combined municipal and industrial wastewaters (1 m3/hr) to study the effect of dissolved oxygen (DO) levels and Fe3ĂŸ dosage on removal efficiency of dissolved and suspended organics prior to biological treatment. High DO (>0.4 mg/L) were found to be detrimental for soluble chemical oxygen demand (COD) removals and iron dosing (up to 20 ppm) did not improve the overall performance. The system performed significantly better at high loading rate (>20 kg COD.m3.d1) where suspended solids and COD removals were greater than 80% and 60%, respectively. This is a significant improvement compared to conventional primary sedimentation tank and the process is a promising alternative for the pretreatment of industrial wastewater
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