215 research outputs found

    Using olive mill wastewate to improve performance in producing electricity from domestic wastewater by using single-chamber microbial fuel cell

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    Improving electricity generation from wastewater (DW) by using olive mill wastewater (OMW) was evaluated using single-chamber microbial fuel cells (MFC). Doing so single-chambers air cathode MFCs with platinum anode were fed with domestic wastewater (DW) alone and mixed with OMW at the ratio of 14:1 (w/w). MFCs fed with DW + OMW gave 0.38 V at 1 kO, while power density from polarization curve was of 124.6mW m 2. The process allowed a total reduction of TCOD and BOD5 of 60% and 69%, respectively, recovering the 29% of the coulombic efficiency. The maximum voltage obtained from MFC fed with DW + OMW was 2.9 times higher than that of cell fed with DW. DNA-fingerprinting showed high bacterial diversity for both experiments and the presence on anodes of exoelectrogenic bacteria, such as Geobacter spp. Electrodes selected peculiar consortia and, in particular, anodes of both experiments showed a similar specialization of microbial communities independently by feeding used

    Drf1-dependent Kinase Interacts with Claspin through a Conserved Protein Motif

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    The Dbf4/Drf1-dependent kinase (DDK) is required for the initiation of DNA replication in eukaryotes. Another protein, Claspin, mediates the activation of a cellular checkpoint response to stalled replication forks and is also a regulator of replication. In this study, we found that DDK phosphorylates Claspin in vitro and forms a nuclear complex containing Cdc7, Drf1, and Claspin in Xenopus egg extracts. In addition, purified Claspin and DDK are capable of a direct in vitro interaction. We identified a conserved binding site on Claspin required for its interaction with DDK. This site corresponds to the first of two sequence repeats in the Chk1-binding domain of Claspin. Furthermore, we have established that two amino acids in this motif, Asp^(861) and Gln^(866), are essential for the interaction between Claspin and DDK. We found that mutant forms of Claspin incapable of interacting with DDK are still able to associate with and activate Chk1 in response to DNA replication blockages. However, Claspin-depleted egg extracts that have been reconstituted with these mutants of Claspin undergo DNA replication more slowly. These findings suggest that the interaction of DDK with Claspin mediates a checkpoint-independent function of Claspin related to DNA replication

    BIOHYDROGEN PRODUCTION FROM AGRICULTURAL AND LIVESTOCK RESIDUES WITHIN AN INTEGRATED BIOENERGY CONCEPT

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    Concerns about energy security, fossil fuel prices, and climate change issues, are leading to increasing renewable energy demand. Hydrogen is considered as one of the main possible energy carriers in future, due to its environmental (it can be converted to energy with the solely emission of water) and energetic (energy content of 120 MJ/kg, three times higher of the gasoline content of 44 MJ/kg) unique properties. If hydrogen is currently being produced mainly by fossil sources, its production from renewable sources answers to the demand of more environment-friendly exploiting alternatives, possibly leading to a renewable-based hydrogen economy. Biomasses are an important renewable source ranging from energy-dedicated crops to livestock waste effluents, agro-industrial wastewaters, food-processing industry residues and organic fractions of the municipal solid waste (OFMSW). Thus the agricultural sector may acquire a renewed importance in the mid-term as a producer of energy sources for renewable biohydrogen production. Among the biological ways to exploit biomasses for hydrogen production, this thesis focused its interest on anaerobic dark fermentation, which can simultaneously guarantee the production of an high-value product (H2) at high evolution rates and the treatment of wastes, thus transformed from an environmental pollution and greenhouse gases emissions source into a valuable resource. If on the one hand this process has lots in common with anaerobic digestion, which already is a well-established technology for treating different biomass types in real-scale plants, on the other hand it is a relatively new approach, which needs to be further studied for improving its performances and being concretely applicable. As a matter of fact, the main disadvantage of dark fermentation is its relatively low yield, compared to other bio-hydrogen production methods, which typically are between 2.4 and 3 mol H2/mol glucose. This represents just the 20-25% of the 12 mol of H2 theoretically obtainable by glucose fermentation. Therefore, generally two different (but not mutually exclusive) options could be chosen for improving the process and making it ready for full-scale applications: the optimization of the biological, biochemical, chemical-physical operative parameters that regulate process; or the coupling of this bioprocess with other technologies capable of exploiting the organic matter not fully used by the dark fermentative approach. For example, Microbial Electrolysis Cells (MECs) are able to biologically oxidize the organic matter (from simple substrates like volatile fatty acids, lactic acid, glucose, cellulose, to actual wastewaters) releasing electrons from an anode to a cathode where potentially pure hydrogen can be formed from protons in the water. Papers I and II basically belong to the first strategy. In Paper I indeed, two waste biomasses were co-digested: in consideration that in the Po Valley area (Italy) swine manures (SM) are yearly produced at high waste density levels and could be a cause of environmental problems, this waste was used as a co-substrate for biohydrogen production by the thermophilic fermentation of easily degradable and carbohydrate-rich materials, such as fruit and vegetable market waste (FVMW). Biohydrogen production rates and process stability were thus simultaneously maximized, thanks to the endogenous buffer capacity of manure, through the combination of a suitable composition (as FVMW/SM) of the feeding material and the hydraulic retention time (HRT) of the process. Thus, livestock manure represented not only a renewable source for supplying the production of biohydrogen, but also a source of alkali to be used for avoiding the addition of exogenous chemicals (alkali) to maintain the pH, and so the metabolic pathways and bacterial communities, into an optimal domain for biohydrogen production. To further study and optimize the bio-H2 production in laboratory-scale processes, but also to find applicable tools for favoring dark fermentation application in full-scale biogas plants, Paper II succeeded in obtaining mixed microbial cultures from natural sources (soil-inocula and anaerobically digested materials) which reached high hydrogen yields with glucose and were used to explore the potential of bio-hydrogen production from four organic substrates of possible interest for full-scale plants (market bio-wastes, maize silage, swine manure, OFMSW). In direct prosecution of the positive co-digestion results shown in Paper I and looking for future transfer of this bioprocess technical solutions to full-scale systems, Paper II used the enriched mixed microflora for evaluating the co-fermentation of a mixture of OFMSW and swine manure in a lab-scale continuously-fed CSTR (continuously stirred tank reactor) digester. Despite the good results obtained, our study suggested that further efforts are needed for future applications of effective biohydrogen fermentation in full-scale plants. Paper III and IV are more focused on the second scientific strategy. Paper III joins the interest toward implementation of bio-H2 in full-scale plants and the strategy of improving the overall recovery of the energy contained in the biomass associating hydrogen production to other bioprocesses. Many authors report that the two-stage anaerobic digestion (AD) process, if compared to traditional and extensively real-scale applied single-stage AD, has also other advantages, such as differentiating the biofuel production (bio-hydrogen and bio-methane), potentially reducing the plant dimensions and costs, improving the overall biogas production yields and allowing higher CH4 concentrations in the biogas produced in the second stage, thus decreasing the biogas purification costs. Therefore, a two-stage laboratory-scale CSTR anaerobic digester, fed with a mixture of agricultural and livestock residues, was monitored for a long run (approximately 700 hours) and compared to a similar one-stage reactor. This study obtained a good hydrogen yield per kg of biomass treated and partially confirmed the advantages previously illustrated, even if it reached almost the same overall energy recovery of the single stage process. Aiming at other possible biological strategies to improve the energy and hydrogen recovery efficiency with the use of effluents from a first dark fermentative stage, a relatively new electrohydrogenesis device (MEC) was studied. Paper IV explores the rate and the yield of biogas (a mixture of H2, CH4 and CO2) produced by MEC exploiting an actual industrial wastewater with high methanol content, a compound never before reported to be used in a MEC device. The energetic recovery and treatment performance of the process was evaluated and also compared with a simulation of anaerobic digestion of the same wastewater, revealing the economical competitiveness of the MEC technology with the AD process. This leads to future research perspectives aiming to realize a laboratory-scale two-stage reactor with a MEC using the volatile-rich effluent of a first dark fermentative stage

    The ITALY ELT ARCHIVE: implications for second language awareness research and teacher education

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    Il ruolo centrale degli archivi e delle collezioni speciali nell’educazione, in particolare nelle scienze umane, è stato studiato per molti anni. Tuttavia, l’uso degli archivi digitali per la formazione degli insegnanti di seconda lingua sembra essere stato trascurato. Inoltre, mentre la ricerca sulla storia dell’insegnamento delle seconde lingue è un campo in espansione in Europa, la storia dell’insegnamento della lingua inglese (ELT) in Italia è ancora poco sviluppata. Per colmare queste lacune, presso l’Università degli Studi di Milano è in corso un progetto per la creazione di un archivio online, ad accesso libero, di materiali ELT pubblicati nel XX secolo e destinati agli studenti italiani di inglese, l’Italy ELT Archive (IELTA). Lo scopo è quello di promuovere la ricerca e di fornire agli insegnanti in servizio e pre-servizio gli strumenti per comprendere i principi alla base dei materiali ELT e sviluppare la loro consapevolezza dei metodi di insegnamento della seconda lingua. Nella prima parte di questo articolo, descriviamo come IELTA è stato progettato e sviluppato per soddisfare sia gli scopi di ricerca che quelli educativi. Nella seconda parte, forniamo esempi di come IELTA possa essere utilizzato per la ricerca sulle variazioni linguistiche e sugli atteggiamenti linguistici, al fine di migliorare la consapevolezza degli insegnanti su questi fenomeni linguistici. Una questione critica nella formazione degli insegnanti è quella di colmare il divario tra la conoscenza teorica dei metodi di insegnamento delle seconde lingue e la loro applicazione pratica. Nell’ultima parte, forniamo esempi di come l’IELTA sia stato utilizzato per migliorare la consapevolezza degli studenti insegnanti sui metodi di insegnamento attraverso l’analisi e la valutazione dei materiali ELT.The pivotal role of archives and special collections in education, particularly in the humanities, has been researched for many years. However, the use of digital archives for second language teacher education appears to have been overlooked. Moreover, while research into the history of second language teaching is an expanding field in Europe, the history of English Language Teaching (ELT) in Italy is still undeveloped. To fill these gaps, a project is underway at the University of Milan to create an online, open-access archive of ELT materials published in the twentieth century targeting Italian learners of English, the Italy ELT Archive (IELTA). The purpose is to promote research and provide in-service and pre-service teachers with tools to understand the principles underpinning ELT materials and develop their awareness of second language teaching methods. In thefirst part of this article, we describe how IELTA was designed and developed to fulfil both research and education purposes. In the second part, we provide examples of how IELTA can be used to research language variation and language attitudes to enhance teachers’ awareness of these linguistic phenomena. One critical issue in teacher education is bridging the gap between theoretical knowledge of second language teaching methods and their practical implementation. In the last part, we provide examples of how IELTA was used to enhance student teachers’ awareness of teaching methods through the analysis and evaluation of ELT materials

    PAEDIATRIC-ONSET PRIMARY SCLEROSING CHOLANGITIS: CLINICAL COURSE AND OUTCOME

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    ABSTRACT BACKGROUND AND AIMS The natural history of paediatric onset PSC and PSC/AIH overlap syndrome is poorly known. Thus, this study was aimed at evaluating the clinical course and outcome of patients with a paediatric onset of disease. MATERIALS AND METHODS Between December 1993 and December 2011, thirty-five patients (median age at diagnosis 15 years), with confirmed PSC by cholangiography (ERC) and PSC/AIH by cholangiography and the modified score for AIH, were traced at Helsinki University Central Hospital. Clinical characteristics (symptoms and signs, associated diseases), diagnostic procedures (lab tests, liver biopsy, ERC) and long-term follow-up (mortality, liver transplantation, recurrence of the disease in the graft, malignancy) were reassessed until December 2013. RESULTS The original diagnosis was PSC in 22 children (63%) and PSC/AIH overlap syndrome in 13 (37%). At diagnosis most of the children had an insidious onset and most an associated IBD, being UC the most common form. Still, 4/35 (11%) had cirrhosis. Endoscopic retrograde cholangiography during follow-up was available for all of the patients and images showed a progression of intra-hepatic disease in 13/28 (46.4%) (p=0.0102). In the last follow-up (median 8 years), all patients were alive. Twenty-eight out of 35 patients (80%) and 13/35 patients (40%) were taken UDCA and immunosuppressive therapy, respectively; 3 patients were without treatment. Transaminases and GGT improved significantly. Four patients (11%) had undergone liver transplantation (after a median 7.5 years) and one was listed; and additional patient was transplanted because of Budd-Chiari syndrome. No difference in graft free survival was seen between patients with PSC and PSC/AIH. Three patients (two with PSC and one with PSC/AIH overlap syndrome) presented with cirrhosis. No malignancy occurred. CONCLUSION The clinical outcome of primary sclerosing cholangitis and overlap syndrome seems comparable including their progression to cirrhosis and requirement for liver transplantation. \u200

    Surveillance of primary sclerosing cholangitis with ERC and brush cytology : risk factors for cholangiocarcinoma

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    Objective: Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disease leading to bile duct strictures and fibrosis, and predisposing to cholangiocarcinoma (CCA). Biliary dysplasia is a known precursor of CCA. In our unit, PSC patients undergo regular surveillance with ERC and brush cytology (BC), and liver transplantation is an option in case with biliary dysplasia. We evaluated the risk factors for biliary dysplasia and CCA based on ERC imaging, BC and liver function tests. Patients and methods: Seven hundred and eighty-eight ERCs were performed with BC for 447 PSC patients. ERC images were evaluated using the modified Amsterdam score, neutrophilic inflammation was assessed in BC, and liver function tests were collected. Ploidy analysis with DNA flow cytometry was performed in cases with advanced PSC or previous suspicious BC/aneuploidy. The endpoint was either a benign disease course (follow-up for >= 2.4 years after the latest ERC), benign histology, biliary dysplasia or CCA. Results: Benign disease course was seen in 424/447 (including 23 cases with biliary dysplasia), and CCA in 17 (3.8%) patients. Gallbladder carcinoma/carcinoma in situ was diagnosed in three patients. Advanced ERC findings, male gender, suspicious BC, aneuploidy in flow cytometry, inflammation, and elevation of ALP, bilirubin, ALT, AST, GGT, CEA and CA19-9 represented significant risk factors for CCA in univariate analysis. Conclusions: PSC patients with advanced bile duct disease and elevated liver enzymes, CEA or CA19-9, inflammation or suspicious BC are most likely to develop CCA. These patients may benefit from surveillance with BC if early liver transplantation is possible.Peer reviewe

    A farm-scale pilot plant for biohydrogen and biomethane production by two-stage fermentation

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    Hydrogen is considered one of the possible main energy carriers for the future, thanks to its unique environmental properties. Indeed, its energy content (120 MJ/kg) can be exploited virtually without emitting any exhaust in the atmosphere except for water. Renewable production of hydrogen can be obtained through common biological processes on which relies anaerobic digestion, a well-established technology in use at farm-scale for treating different biomass and residues. Despite two-stage hydrogen and methane producing fermentation is a simple variant of the traditional anaerobic digestion, it is a relatively new approach mainly studied at laboratory scale. It is based on biomass fermentation in two separate, seuqential stages, each maintaining conditions optimized to promote specific bacterial consortia: in the first acidophilic reactorhydrogen is produced production, while volatile fatty acids-rich effluent is sent to the second reactor where traditional methane rich biogas production is accomplished. A two-stage pilot-scale plant was designed, manufactured and installed at the experimental farm of the University of Milano and operated using a biomass mixture of livestock effluents mixed with sugar/starch-rich residues (rotten fruits and potatoes and expired fruit juices), afeedstock mixture based on waste biomasses directly available in the rural area where plant is installed. The hydrogenic and the methanogenic reactors, both CSTR type, had a total volume of 0.7m3 and 3.8 m3 respectively, and were operated in thermophilic conditions (55 2 °C) without any external pH control, and were fully automated. After a brief description of the requirements of the system, this contribution gives a detailed description of its components and of engineering solutions to the problems encountered during the plant realization and start-up. The paper also discusses the results obtained in a first experimental run which lead to production in the range of previous laboratory results, with a typical hydrogen and methane specific productivity of 2.2 and 0.5 Nm3/m3reactor per day, in the first and second stage of the plant respectively. At our best knowledge, this plant is one of the very first prototypes producing biohydrogen at farm scale, and it represents a distributed, small scale demonstration to obtain hydrogen from renewable waste-sources

    An operational strategy to produce Bio-hydrogen : the use of digestate for process control

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    A semi-continuous digester was fed twice a day with a concentrated solution of glucose (100 g l-1) and monitored for a 30-days period, with the aim of testing the possibility of utilizing the digestate of a traditional biogas plant, after a heat-shock at 100\ubaC, for controlling process parameters (organic loading rate OLR, pH, volatile fatty acids VFA concentration), by adding it to the fresh substrate at a ratio R of the total feeding volume. The process resulted instable for OLR=10 gVS L-1and R=0.7, while more stable for OLR of 5 gVS L-1and R=0.85. The maximum bio-hydrogen production rate in stable conditions was 100 NmLH2 h-1 and the conversion yields were 1.7 - 1.8 molH2 mol-1glucose. The produced biogas showed always complete absence of methane

    Yield of prolonged wireless pH monitoring in achalasia patients successfully treated with pneumatic dilation

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    Background: Gastro-oesophageal reflux disease (GORD) is a long-term complication of achalasia treatments. The aim of our study was to evaluate the yield of prolonged wireless pH monitoring in patients with successfully treated achalasia and its influence on proton pump inhibitor (PPI) use. Methods: Twenty-five patients with achalasia who underwent prolonged wireless pH monitoring after a successful treatment with pneumatic dilation were enrolled. pH variables were analysed in the first 24 hours of monitoring to determine if tracings were indicative of GORD; the same variables were analysed in the following 24-hour period in order to obtain a worst-day diagnosis of GORD. PPI therapy before and after the test was recorded. Results: Five out of 25 patients had GORD diagnosis during the first day of monitoring and four of them had oesophagitis at endoscopy. During the following days of monitoring four more patients had a diagnosis of GORD. Out of the 25 patients, PPIs were started after the test in six asymptomatic GORD-positive ones, whereas prescription of PPIs was stopped without detrimental effect on symptoms in three GORD-negative patients. Conclusions: Prolonged wireless pH monitoring is a useful test to be added to endoscopy in order to evaluate GORD and to optimise antisecretory treatment in successfully treated achalasia patients
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