53 research outputs found

    High energy density storage of gaseous marine fuels: An innovative concept and its application to a hydrogen powered ferry

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    The upcoming stricter limitations on both pollutant and greenhouse gases emissions represent a challenge for the shipping sector. The entire ship design process requires an approach to innovation, with a particular focus on both the fuel choice and the power generation system. Among the possible alternatives, natural gas and hydrogen based propulsion systems seem to be promising in the medium and long term. Nonetheless, natural gas and hydrogen storage still represents a problem in terms of cargo volume reduction. This paper focuses on the storage issue, considering compressed gases, and presents an innovative solution, which has been developed in the European project GASVESSEL\uae that allows to store gaseous fuels with an energy density higher than conventional intermediate pressure containment systems. After a general overview of natural gas and hydrogen as fuels for shipping, a case study of a small Roll-on/Roll-off passenger ferry retrofit is proposed. The study analyses the technical feasibility of the installation of a hybrid power system with batteries and polymer electrolyte membrane fuel cells, fuelled by hydrogen. In particular, a process simulation model has been implemented to assess the quantity of hydrogen that can be stored on board, taking into account boundary conditions such as filling time, on shore storage capacity and cylinder wall temperature. The simulation results show that, if the fuel cells system is run continuously at steady state, to cover the energy need for one day of operation 140 kg of hydrogen are required. Using the innovative pressure cylinder at a storage pressure of 300 bar the volume required by the storage system, assessed on the basis of the containment system outer dimensions, is resulted to be 15.2 m3 with a weight of 2.5 ton. Even if the innovative type of pressure cylinder allows to reach an energy density higher than conventional intermediate pressure cylinders, the volume necessary to store a quantity of energy typical for the shipping sector is many times higher than that required by conventional fuels today used. The analysis points out, as expected, that the filling process is critical to maximize the stored hydrogen mass and that it is critical to measure the temperature of the cylinder walls in order not to exceed the material limits. Nevertheless, for specific application such as the one considered in the paper, the introduction of gaseous hydrogen as fuel, can be considered for implementing zero local emission propulsion system in the medium term

    Genotoxic effect of exposure to metal(loid)s. A molecular epidemiology survey of populations living and working in Panasqueira mine area, Portugal

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    Previous studies investigating the exposure to metal(loid)s of populations living in the Panasqueira mine area of central Portugal found a higher internal dose of elements such as arsenic, chromium, lead, manganese, molybdenum and zinc in exposed individuals. The aims of the present study were to evaluate the extent of genotoxic damage caused by environmental and occupational exposure in individuals previously tested for metal(loid) levels in different biological matrices, and the possible modulating role of genetic polymorphisms involved in metabolism and DNA repair. T-cell receptor mutation assay, comet assay, micronucleus (MN) test and chromosomal aberrations (CA) were performed in a group of 122 subjects working in the Panasqueira mine or living in the same region. The modifying effect of polymorphisms in GSTA2, GSTM1, GSTP1, GSTT1, XRCC1, APEX1, MPG, MUTYH, OGG1, PARP1, PARP4, ERCC1, ERCC4, and ERCC5 genes was investigated. Significant increases in the frequency of all biomarkers investigated were found in exposed groups, however those environmentally exposed were generally higher. Significant influences of polymorphisms were observed for GSTM1 deletion and OGG1 rs1052133 on CA frequencies, APEX1 rs1130409 on DNA damage, ERCC1 rs3212986 on DNA damage and CA frequency, and ERCC4 rs1800067 on MN and CA frequencies. Our results show that the metal(loid) contamination in the Panasqueira mine area induced genotoxic damage both in individuals working in the mine or living in the area. The observed effects are closely associated to the internal exposure dose, and are more evident in susceptible genotypes. The urgent intervention of authorities is required to protect exposed populations

    The SARS-coronavirus-host interactome

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    Coronaviruses (CoVs) are important human and animal pathogens that induce fatal respiratory, gastrointestinal and neurological disease. The outbreak of the severe acute respiratory syndrome (SARS) in 2002/2003 has demonstrated human vulnerability to (Coronavirus) CoV epidemics. Neither vaccines nor therapeutics are available against human and animal CoVs. Knowledge of host cell proteins that take part in pivotal virus-host interactions could define broad-spectrum antiviral targets. In this study, we used a systems biology approach employing a genome-wide yeast-two hybrid interaction screen to identify immunopilins (PPIA, PPIB, PPIH, PPIG, FKBP1A, FKBP1B) as interaction partners of the CoV non-structural protein 1 (Nsp1). These molecules modulate the Calcineurin/NFAT pathway that plays an important role in immune cell activation. Overexpression of NSP1 and infection with live SARS-CoV strongly increased signalling through the Calcineurin/NFAT pathway and enhanced the induction of interleukin 2, compatible with late-stage immunopathogenicity and long-term cytokine dysregulation as observed in severe SARS cases. Conversely, inhibition of cyclophilins by cyclosporine A (CspA) blocked the replication of CoVs of all genera, including SARS-CoV, human CoV-229E and -NL-63, feline CoV, as well as avian infectious bronchitis virus. Non-immunosuppressive derivatives of CspA might serve as broad-range CoV inhibitors applicable against emerging CoVs as well as ubiquitous pathogens of humans and livestock

    Mutations in the Cholesterol Transporter Gene ABCA5 Are Associated with Excessive Hair Overgrowth

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    Inherited hypertrichoses are rare syndromes characterized by excessive hair growth that does not result from androgen stimulation, and are often associated with additional congenital abnormalities. In this study, we investigated the genetic defect in a case of autosomal recessive congenital generalized hypertrichosis terminalis (CGHT) (OMIM135400) using whole-exome sequencing. We identified a single base pair substitution in the 5′ donor splice site of intron 32 in the ABC lipid transporter gene ABCA5 that leads to aberrant splicing of the transcript and a decrease in protein levels throughout patient hair follicles. The homozygous recessive disruption of ABCA5 leads to reduced lysosome function, which results in an accumulation of autophagosomes, autophagosomal cargos as well as increased endolysosomal cholesterol in CGHT keratinocytes. In an unrelated sporadic case of CGHT, we identified a 1.3 Mb cryptic deletion of chr17q24.2-q24.3 encompassing ABCA5 and found that ABCA5 levels are dramatically reduced throughout patient hair follicles. Collectively, our findings support ABCA5 as a gene underlying the CGHT phenotype and suggest a novel, previously unrecognized role for this gene in regulating hair growth

    The SARS-Coronavirus-Host Interactome: Identification of Cyclophilins as Target for Pan-Coronavirus Inhibitors

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    Coronaviruses (CoVs) are important human and animal pathogens that induce fatal respiratory, gastrointestinal and neurological disease. The outbreak of the severe acute respiratory syndrome (SARS) in 2002/2003 has demonstrated human vulnerability to (Coronavirus) CoV epidemics. Neither vaccines nor therapeutics are available against human and animal CoVs. Knowledge of host cell proteins that take part in pivotal virus-host interactions could define broad-spectrum antiviral targets. In this study, we used a systems biology approach employing a genome-wide yeast-two hybrid interaction screen to identify immunopilins (PPIA, PPIB, PPIH, PPIG, FKBP1A, FKBP1B) as interaction partners of the CoV non-structural protein 1 (Nsp1). These molecules modulate the Calcineurin/NFAT pathway that plays an important role in immune cell activation. Overexpression of NSP1 and infection with live SARS-CoV strongly increased signalling through the Calcineurin/NFAT pathway and enhanced the induction of interleukin 2, compatible with late-stage immunopathogenicity and long-term cytokine dysregulation as observed in severe SARS cases. Conversely, inhibition of cyclophilins by cyclosporine A (CspA) blocked the replication of CoVs of all genera, including SARS-CoV, human CoV-229E and -NL-63, feline CoV, as well as avian infectious bronchitis virus. Non-immunosuppressive derivatives of CspA might serve as broad-range CoV inhibitors applicable against emerging CoVs as well as ubiquitous pathogens of humans and livestock

    The role of Aip4/Itch, a member of Nedd4 family E3 ligases, in the ubiquitination of proteins involved in RTKs endocytosis

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    ABSTRACT E’ stata utilizzata una nuova tecnica di approccio genomico (WISE: Whole Interactome Scanning Experiment) per cercare, nell’intero proteoma umano, proteine contenenti peptidi in grado di interagire con i domini SH3 dell’anfifisina I e dell’endofilina, due proteine coinvolte nel traffico vescicolare. Dall’analisi dei risultati sono emersi degli interattori noti quali, la dinamina e la sinaptojanina e dei nuovi possibili interattori (Langraf et al.; 2004). Tra questi ultimi è stata focalizzata l’attenzione sulla proteina Aip4/Itch, una E3 ligasi appartenente alla famiglia di Nedd4, in quanto negli ultimi anni è stato dimostrato che l’ubiquitinazione ha un ruolo sempre più importante per la regolazione del traffico vescicolare. E’ stata confermato l’interazione interazione, in vitro, tra Itch e anfifisina, dimostrando che l’amfifisina I co-immunoprecipita con Itch, in vivo; tuutavia, nonostante il forte legame l’anfifisina non viene ubiquitinata da Itch. Questo fenomeno ha fatto supporre che il legame anfifisina-Itch possa promuovere la localizzazione e l’attività enzimatica di Itch a livello delle vescicole endocitiche e dei compartimenti endosomali. Alla luce di questa ipotesi sono state testate sistematicamente diverse proteine coinvolte nell’endocitosi dei recettori tirosin chinasici per verificare quali potevano essere bersaglio dell’attività ubiquitinante di Itch, sia in vivo che in vitro. Alla fine di questo lavoro di tesi è stato dimostrato che Itch è implicata nel legame e nell’ubiquitinazione di tre proteine: Hrs, STAM2 e Eps15. Queste tre proteine sono le costituenti di un etero-complesso multivalente essenziale per lo smistamento di proteine ubiquitinate nei diversi compartimenti vescicolari, in particolare sono implicate nel traffico vescicolare tra gli endosomi tardivi e i lisosomi.ABSTRACT We have used a recently developed genomic approach (WISE: Langraf et al.; 2004), to search the whole proteome for proteins containing peptides that could bind to the SH3 domains of amphiphysin I and endophilin, two proteins implicated in vesicle trafficking. Among the inferred candidate ligands we focused on the protein Itch, a HECT domain ubiquitin ligase that was recently shown to participate in ubiquitination processes affecting the internalization of the EGF receptor. Itch can be co-immunoprecipitated with Amphiphysin I, in vivo, suggesting that this interaction could promote the enzymatic activity of Itch in endocytic vesicles and endosome compartments. We are systematically testing a number of proteins involved in receptor endocytosis to see whether they are targets of the ubiquitination activity of Itch, in vivo or in vitro. We demonstrated that Itch is implicated in the binding and ubiquitination of three proteins HRS, STAM2, Eps15 that form a multivalent complex essential in sorting ubiquitinate

    Multi-objective optimization of hybrid PEMFC/Li-ion battery propulsion systems for small and medium size ferries

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    Hybrid Polymer Electrolyte Membrane Fuel Cells/Lithium-ion battery powertrains are a promising solution for zero-local-emissions marine propulsion. The present study aims to optimize the design and operation of such hybrid powertrain for small-size passenger ferries, taking into account the performance degradation of both fuel cells and batteries. A Mixed-Integer Linear-Programming approach and a hierarchical method are adopted to concurrently minimize the fuel cells degradation, the capital expenditure and the operating expenditure, while constraints are included in the model to limit the battery degradation. The results show that the proposed multi-objective optimization can lead to a reduction of fuel cells degradation by up to 65% compared to a cost-minimization only. However, this can imply an increase in the battery capacity by up to 136%. The proposed method has general validity, and it is a useful tool for both preliminary design and choice of the optimal energy management strategy for ships energy systems

    Comparison of different plant layouts and fuel storage solutions for fuel cells utilization on a small ferry

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    In the path towards the decarbonization of the maritime sector, Low Temperature Polymer Electrolyte Membrane Fuel Cells (LT-PEMFC) fed by hydrogen are gaining attention as they could guarantee zero local emissions propulsion. In this study, a process simulation model is implemented to analyze the influence of peak shaving in a hybrid LT-PEMFC/lithium-ion battery power plant for the propulsion of a small size RoRo car and passenger ferry in different operative conditions. Results show that battery peak shaving could allow a reduction of FC installed power of up to 72%. As for compressed H2 storage, the results show that for sailing time in the range of 5\u201310 min, Type I cylinders at 250 bar are a viable option. For longer routes, Type III cylinders at 350 bar or Type IV cylinders at 700 bar should be considered in order to avoid excessive reduction in the pay-load
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