935 research outputs found

    Polyhydroxyalkanoate as a slow-release carbon source for in situ bioremediation of contaminated aquifers: from laboratory investigation to pilot-scale testing in the field

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    A pilot-scale study aiming to evaluate the potential use of poly-3-hydroxy-butyrate (PHB) as an electron donor source for in situ bioremediation of chlorinated hydrocarbons in groundwater was conducted. Compared with commercially available electron donors, PHB offers a restricted fermentation pathway (i.e., through acetic acid and molecular hydrogen) by avoiding the formation of any residual carbon that could potentially spoil groundwater quality. The pilot study was carried out at an industrial site in Italy, heavily contaminated by different chlorinated aliphatic hydrocarbons (CAHs). Prior to field testing, PHB was experimentally verified as a suitable electron donor for biological reductive dechlorination processes at the investigated site by microcosm studies carried out on site aquifer material and measuring the quantitative transformation of detected CAHs to ethene. Owing to the complex geological characteristics of the aquifer, the use of a groundwater circulation well (GCW) was identified as a potential strategy to enable effective delivery and distribution of electron donors in less permeable layers and to mobilise contaminants. A 3-screened, 30-m-deep GCW coupled with an external treatment unit was installed at the site. The effect of PHB fermentation products on the in situ reductive dechlorination processes were evaluated by quantitative real-time polymerase chain reaction (qPCR). The results from the first 4 months of operation clearly demonstrated that the PHB fermentation products were effectively delivered to the aquifer and positively influenced the biological dechlorination activity. Indeed, an increased abundance of Dehalococcoides mccartyi (up to 6.6 fold) and reduced CAH concentrations at the installed monitoring wells were observed

    Swelling, mechanical and barrier properties of albedo-based films prepared in the presence of phaseolin crosslinked or not by transglutaminase

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    Edible films were obtained from Citrus paradisi grapefruit albedo homogenates and bean protein phaseolin modified or not by the enzyme transglutaminase. Swelling capability, barrier performance to water vapor, oxygen and carbon dioxide, and mechanical properties of such films were investigated. The addition of the protein, mostly in the presence of transglutaminase, provide films less swellable at pH values above 5 compared to films made by albedo homogenates only, whereas the action of the enzyme clearly improves mechanical properties producing more stretchable and elastic films. Moreover, transglutaminase-mediated cross-linking of phaseolin gives rise to films less permeable to carbon dioxide and able to offer a high barrier to water vapor. These findings suggest that albedo-phaseolin film prepared in the presence of transglutaminase can be a promising candidate to be used as food edible wrap

    Impact of transglutaminase treatment on properties and in vitro digestibility of white bean (Phaseolus vulgaris L.) flour

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    Common beans (Phaseolus vulgaris L.) are rich in nutrients and have significant amounts of proteins and complex carbohydrates, besides to be rich in unsaturated fatty acids and dietary fibres. Consumption of beans could be improved by processing them into flour. In this study the effect of microbial transglutaminase (TG) on the structure, physical (colour parameters, moisture, water holding capacity), thermal properties and in vitro digestion of undehulled (WB) and manually dehulled (SB) flour samples from white common beans (P. vulgaris L.) was evaluated. Flour samples were incubated in the absence and presence of TG (WB/TG and SB/TG). We observed that the enzyme is able to catalyse the formation of polymers, suggesting that the proteins occurring in the bean flour act as TG substrates. Microstructure of samples was examined by Scanning Electron Microscopy (SEM), while thermal properties were studied by Differential Scanning Calorimetry. Microstructural results showed that the TG-treated samples possess a more compact structure, made of starch granules surrounded by proteins that, presumably, contain TG-catalysed polymers. Moreover, TG treatment had a major impact on colour, water holding capacity (WHC) and thermal properties. In particular, WB and SB samples presented a darker colour than WB/TG and SB/TG samples, while the latter showed reduced WHC that was only 30% and 37% of WB and SB samples, respectively. The transition enthalpy (ΔH) in the temperature range from 57 to 70 °C (WB, WB/TG) and from 60 to 68 °C (SB, SB/TG) followed the order: WB/TG > WB and SB/TG > WB, respectively. In vitro digestion experiments indicate that the presence of isopeptide bonds decreased the digestibility of TG-treated flour samples

    Microbial Community Changes in a Chlorinated Solvents Polluted Aquifer Over the Field Scale Treatment With Poly-3-Hydroxybutyrate as Amendment

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    This study investigated the organohalide-respiring bacteria (OHRB) and the supporting microbial populations operating in a pilot scale plant employing poly-3-hydroxybutyrate (PHB), a biodegradable polymer produced by bacteria from waste streams, for the in situ bioremediation of groundwater contaminated by chlorinated solvents. The bioremediation was performed in ground treatment units, including PHB reactors as slow release source of electron donors, where groundwater extracted from the wells flows through before the re-infiltration to the low permeability zones of the aquifer. The coupling of the biological treatment with groundwater recirculation allowed to drastically reducing the contamination level and the remediation time by efficiently stimulating the growth of autochthonous OHRB and enhancing the mobilization of the pollutants. Quantitative PCR performed along the external treatment unit showed that the PHB reactor may efficiently act as an external incubator to growing Dehalococcoides mccartyi, known to be capable of fully converting chlorinated ethenes to innocuous end-products. The slow release source of electron donors for the bioremediation process allowed the establishment of a stable population of D. mccartyi, mainly carrying bvcA and vcrA genes which are implicated in the metabolic conversion of vinyl chloride to harmless ethene. Next generation sequencing was performed to analyze the phylogenetic diversity of the groundwater microbiome before and after the bioremediation treatment and allowed the identification of the microorganisms working closely with organohalide-respiring bacteria

    Metabolic synergies in the biotransformation of organic and metallic toxic compounds by a saprotrophic soil fungus

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    The saprotrophic fungus Penicillium griseofulvum was chosen as model organism to study responses to a mixture of hexachlorocyclohexane (HCH) isomers (α-HCH, β-HCH, γ-HCH, δ-HCH) and of potentially toxic metals (vanadium, lead) in solid and liquid media. The P. griseofulvum FBL 500 strain was isolated from polluted soil containing high concentrations of HCH isomers and potentially toxic elements (Pb, V). Experiments were performed in order to analyse the tolerance/resistance of this fungus to xenobiotics, and to shed further light on fungal potential in inorganic and organic biotransformations. The aim was to examine the ecological and bioremedial potential of this fungus verifying the presence of mechanisms that allow it to transform HCH isomers and metals under different, extreme, test conditions. To our knowledge, this work is the first to provide evidence on the biotransformation of HCH mixtures, in combination with toxic metals, by a saprotrophic non-white-rot fungus and on the metabolic synergies involved

    Differential cross section measurements for the production of a W boson in association with jets in proton–proton collisions at √s = 7 TeV

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    Measurements are reported of differential cross sections for the production of a W boson, which decays into a muon and a neutrino, in association with jets, as a function of several variables, including the transverse momenta (pT) and pseudorapidities of the four leading jets, the scalar sum of jet transverse momenta (HT), and the difference in azimuthal angle between the directions of each jet and the muon. The data sample of pp collisions at a centre-of-mass energy of 7 TeV was collected with the CMS detector at the LHC and corresponds to an integrated luminosity of 5.0 fb[superscript −1]. The measured cross sections are compared to predictions from Monte Carlo generators, MadGraph + pythia and sherpa, and to next-to-leading-order calculations from BlackHat + sherpa. The differential cross sections are found to be in agreement with the predictions, apart from the pT distributions of the leading jets at high pT values, the distributions of the HT at high-HT and low jet multiplicity, and the distribution of the difference in azimuthal angle between the leading jet and the muon at low values.United States. Dept. of EnergyNational Science Foundation (U.S.)Alfred P. Sloan Foundatio

    Juxtaposing BTE and ATE – on the role of the European insurance industry in funding civil litigation

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    One of the ways in which legal services are financed, and indeed shaped, is through private insurance arrangement. Two contrasting types of legal expenses insurance contracts (LEI) seem to dominate in Europe: before the event (BTE) and after the event (ATE) legal expenses insurance. Notwithstanding institutional differences between different legal systems, BTE and ATE insurance arrangements may be instrumental if government policy is geared towards strengthening a market-oriented system of financing access to justice for individuals and business. At the same time, emphasizing the role of a private industry as a keeper of the gates to justice raises issues of accountability and transparency, not readily reconcilable with demands of competition. Moreover, multiple actors (clients, lawyers, courts, insurers) are involved, causing behavioural dynamics which are not easily predicted or influenced. Against this background, this paper looks into BTE and ATE arrangements by analysing the particularities of BTE and ATE arrangements currently available in some European jurisdictions and by painting a picture of their respective markets and legal contexts. This allows for some reflection on the performance of BTE and ATE providers as both financiers and keepers. Two issues emerge from the analysis that are worthy of some further reflection. Firstly, there is the problematic long-term sustainability of some ATE products. Secondly, the challenges faced by policymakers that would like to nudge consumers into voluntarily taking out BTE LEI

    Penilaian Kinerja Keuangan Koperasi di Kabupaten Pelalawan

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    This paper describe development and financial performance of cooperative in District Pelalawan among 2007 - 2008. Studies on primary and secondary cooperative in 12 sub-districts. Method in this stady use performance measuring of productivity, efficiency, growth, liquidity, and solvability of cooperative. Productivity of cooperative in Pelalawan was highly but efficiency still low. Profit and income were highly, even liquidity of cooperative very high, and solvability was good
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