Showing papers by "University of Patras published in 2014"

Valorization of industrial waste and by-product streams via fermentation for the production of chemicals and biopolymers

Abstract: The transition from a fossil fuel-based economy to a bio-based economy necessitates the exploitation of synergies, scientific innovations and breakthroughs, and step changes in the infrastructure of chemical industry. Sustainable production of chemicals and biopolymers should be dependent entirely on renewable carbon. White biotechnology could provide the necessary tools for the evolution of microbial bioconversion into a key unit operation in future biorefineries. Waste and by-product streams from existing industrial sectors (e.g., food industry, pulp and paper industry, biodiesel and bioethanol production) could be used as renewable resources for both biorefinery development and production of nutrient-complete fermentation feedstocks. This review focuses on the potential of utilizing waste and by-product streams from current industrial activities for the production of chemicals and biopolymers via microbial bioconversion. The first part of this review presents the current status and prospects on fermentative production of important platform chemicals (i.e., selected C2-C6 metabolic products and single cell oil) and biopolymers (i.e., polyhydroxyalkanoates and bacterial cellulose). In the second part, the qualitative and quantitative characteristics of waste and by-product streams from existing industrial sectors are presented. In the third part, the techno-economic aspects of bioconversion processes are critically reviewed. Four case studies showing the potential of case-specific waste and by-product streams for the production of succinic acid and polyhydroxyalkanoates are presented. It is evident that fermentative production of chemicals and biopolymers via refining of waste and by-product streams is a highly important research area with significant prospects for industrial applications.

Social acceptance of renewable energy sources: A review of contingent valuation applications

Abstract: This paper presents a literature review addressing the public acceptance of renewable energy as a replacement for fossil fuels in electricity production. This review was motivated by the global tendency for a substitution of conventional fuels by renewable energy sources (RES) during the global financial crisis. It studies research on the preferences and attitudes of local communities towards investments in renewable energy projects and their perception of the use of new energy technologies in their daily lives, through various case studies worldwide. An effort is made to identify the parameters that influence consumers' energy behaviour, together with their interest, or lack thereof, in the environmental impact of using fossil fuels to produce energy and their willingness to reduce it. Applications of contingent valuation are examined, which are employed to analyse public attitudes towards the use of RES for electricity production. Willingness-to-pay is observed to be correlated to socioeconomic characteristics including education, interest in environmental issues and knowledge of RES. Finally, the profile of a typical green energy consumer and appropriate policy paths for the penetration of RES into the energy market are outlined.

Updates of the HbVar database of human hemoglobin variants and thalassemia mutations

Abstract: HbVar (http://globin.bx.psu.edu/hbvar) is one of the oldest and most appreciated locus-specific databases launched in 2001 by a multi-center academic effort to provide timely information on the genomic alterations leading to hemoglobin variants and all types of thalassemia and hemoglobinopathies. Database records include extensive phenotypic descriptions, biochemical and hematological effects, associated pathology and ethnic occurrence, accompanied by mutation frequencies and references. Here, we report updates to >600 HbVar entries, inclusion of population-specific data for 28 populations and 27 ethnic groups for α-, and β-thalassemias and additional querying options in the HbVar query page. HbVar content was also inter-connected with two other established genetic databases, namely FINDbase (http://www.findbase.org) and Leiden Open-Access Variation database (http://www.lovd.nl), which allows comparative data querying and analysis. HbVar data content has contributed to the realization of two collaborative projects to identify genomic variants that lie on different globin paralogs. Most importantly, HbVar data content has contributed to demonstrate the microattribution concept in practice. These updates significantly enriched the database content and querying potential, enhanced the database profile and data quality and broadened the inter-relation of HbVar with other databases, which should increase the already high impact of this resource to the globin and genetic database community.

Conceptual design of the International Axion Observatory (IAXO)

Abstract: The International Axion Observatory (IAXO) will be a forth generation axion helioscope. As its primary physics goal, IAXO will look for axions or axion-like particles (ALPs) originating in the Sun via the Primakoff conversion of the solar plasma photons. In terms of signal-to-noise ratio, IAXO will be about 4–5 orders of magnitude more sensitive than CAST, currently the most powerful axion helioscope, reaching sensitivity to axion-photon couplings down to a few × 10−12 GeV−1 and thus probing a large fraction of the currently unexplored axion and ALP parameter space. IAXO will also be sensitive to solar axions produced by mechanisms mediated by the axion-electron coupling gae with sensitivity — for the first time — to values of gae not previously excluded by astrophysics. With several other possible physics cases, IAXO has the potential to serve as a multi-purpose facility for generic axion and ALP research in the next decade. In this paper we present the conceptual design of IAXO, which follows the layout of an enhanced axion helioscope, based on a purpose-built 20 m-long 8-coils toroidal superconducting magnet. All the eight 60cm-diameter magnet bores are equipped with focusing x-ray optics, able to focus the signal photons into ~ 0.2 cm2 spots that are imaged by ultra-low-background Micromegas x-ray detectors. The magnet is built into a structure with elevation and azimuth drives that will allow for solar tracking for ~ 12 h each day.

Determinants of Non-Performing Loans: The Case of Eurozone

Abstract: Summary: The purpose of the present study is to identify the factors affecting the non-performing loans rate (NPL) of Eurozone’s banking systems for the period 2000-2008, just before the beginning of the recession. In our days, Eurozone is in the middle of an unprecedented financial crisis, calling into question the soundness of the banking systems of European countries. Looking at both macro-variables (e.g. annual percentage growth rate of gross domestic product, public debt as % of gross domestic product, unemployment) and micro-variables (e.g. loans to deposits ratio, return on assets, return on equity), we investigate which factors determine NPL on aggregate level. Overall, our findings reveal strong correlations between NPL and various macroeconomic (public debt, unemployment, annual percentage growth rate of gross domestic product) and bank-specific (capital adequacy ratio, rate of nonperforming loans of the previous year and return on equity) factors.

Titanium dioxide (anatase and rutile): surface chemistry, liquid-solid interface chemistry, and scientific synthesis of supported catalysts.

Abstract: Solid Interface Chemistry, and Scientific Synthesis of Supported Catalysts Kyriakos Bourikas,† Christos Kordulis,‡,§ and Alexis Lycourghiotis*,‡ †School of Science and Technology, Hellenic Open University, Tsamadou 13-15, GR-26222 Patras, Greece ‡Department of Chemistry, University of Patras, GR-26500 Patras, Greece Institute of Chemical Engineering and High-Temperature Chemical Processes (FORTH/ICE-HT), P.O. Box 1414, GR-26500 Patras, Greece

Genome sequence of the tsetse fly (Glossina morsitans ): Vector of African trypanosomiasis

Abstract: Tsetse flies are the sole vectors of human African trypanosomiasis throughout sub-Saharan Africa. Both sexes of adult tsetse feed exclusively on blood and contribute to disease transmission. Notable differences between tsetse and other disease vectors include obligate microbial symbioses, viviparous reproduction, and lactation. Here, we describe the sequence and annotation of the 366-megabase Glossina morsitans morsitans genome. Analysis of the genome and the 12,308 predicted protein–encoding genes led to multiple discoveries, including chromosomal integrations of bacterial (Wolbachia) genome sequences, a family of lactation-specific proteins, reduced complement of host pathogen recognition proteins, and reduced olfaction/chemosensory associated genes. These genome data provide a foundation for research into trypanosomiasis prevention and yield important insights with broad implications for multiple aspects of tsetse biology.

Symbionts commonly provide broad spectrum resistance to viruses in insects: a comparative analysis of Wolbachia strains.

Abstract: In the last decade, bacterial symbionts have been shown to play an important role in protecting hosts against pathogens. Wolbachia, a widespread symbiont in arthropods, can protect Drosophila and mosquito species against viral infections. We have investigated antiviral protection in 19 Wolbachia strains originating from 16 Drosophila species after transfer into the same genotype of Drosophila simulans. We found that approximately half of the strains protected against two RNA viruses. Given that 40% of terrestrial arthropod species are estimated to harbour Wolbachia, as many as a fifth of all arthropods species may benefit from Wolbachia-mediated protection. The level of protection against two distantly related RNA viruses--DCV and FHV--was strongly genetically correlated, which suggests that there is a single mechanism of protection with broad specificity. Furthermore, Wolbachia is making flies resistant to viruses, as increases in survival can be largely explained by reductions in viral titer. Variation in the level of antiviral protection provided by different Wolbachia strains is strongly genetically correlated to the density of the bacteria strains in host tissues. We found no support for two previously proposed mechanisms of Wolbachia-mediated protection--activation of the immune system and upregulation of the methyltransferase Dnmt2. The large variation in Wolbachia's antiviral properties highlights the need to carefully select Wolbachia strains introduced into mosquito populations to prevent the transmission of arboviruses.

Chemotherapy-induced peripheral neuropathy in adults: a comprehensive update of the literature

Abstract: Commonly used chemotherapeutic agents in oncology/hematology practice, causing toxic peripheral neuropathy, include taxanes, platinum compounds, vinca alkaloids, proteasome inhibitors, and antiangiogenic/immunomodulatory agents. This review paper intends to put together and discuss the spectrum of chemotherapy-induced peripheral neuropathy (CIPN) characteristics so as to highlight areas of future research to pursue on the topic. Current knowledge shows that the pathogenesis of CIPN still remains elusive, mostly because there are several sites of involvement in the peripheral nervous system. In any case, it is acknowledged that the dorsal root ganglia of the primary sensory neurons are the most common neural targets of CIPN. Both the incidence and severity of CIPN are clinically under- and misreported, and it has been demonstrated that scoring CIPN with common toxicity scales is associated with significant inter-observer variability. Only a proportion of chemotherapy-treated patients develop treatment-emergent and persistent CIPN, and to date it has been impossible to predict high-and low-risk subjects even within groups who receive the same drug regimen. This issue has recently been investigated in the context of pharmacogenetic analyses, but these studies have not implemented a proper methodological approach and their results are inconsistent and not really clinically relevant. As such, a stringent approach has to be implemented to validate that information. Another open issue is that, at present, there is insufficient evidence to support the use of any of the already tested chemoprotective agents to prevent or limit CIPN. The results of comprehensive interventions, including clinical, neurophysiological, and pharmacogenetic approaches, are expected to produce a consistent advantage for both doctors and patients and thus allow the registration and analysis of reliable data on the true characteristics of CIPN, eventually leading to potential preventive and therapeutic interventions.

Mortar-based systems for externally bonded strengthening of masonry

Abstract: Mortar-based composite materials appear particularly promising for use as externally bonded reinforcement (EBR) systems for masonry structures. Nevertheless, their mechanical performance, which may significantly differ from that of Fibre Reinforced Polymers, is still far from being fully investigated. Furthermore, standardized and reliable testing procedures have not been defined yet. The present paper provides an insight on experimental-related issues arising from campaigns on mortar-based EBRs carried out by laboratories in Italy, Portugal and Spain. The performance of three reinforcement systems made out of steel, carbon and basalt textiles embedded in inorganic matrices has been investigated by means of uniaxial tensile coupon testing and bond tests on brick and stone substrates. The experimental results contribute to the existing knowledge regarding the structural behaviour of mortar-based EBRs against tension and shear bond stress, and to the development of reliable test procedures aiming at their homogenization/standardization.

The PREDICTS database: a global database of how local terrestrial biodiversity responds to human impacts

Abstract: Biodiversity continues to decline in the face of increasing anthropogenic pressures such as habitat destruction, exploitation, pollution and introduction of alien species Existing global databases of species’ threat status or population time series are dominated by charismatic species The collation of datasets with broad taxonomic and biogeographic extents, and that support computation of a range of biodiversity indicators, is necessary to enable better understanding of historical declines and to project – and avert – future declines We describe and assess a new database of more than 16 million samples from 78 countries representing over 28,000 species, collated from existing spatial comparisons of local-scale biodiversity exposed to different intensities and types of anthropogenic pressures, from terrestrial sites around the world The database contains measurements taken in 208 (of 814) ecoregions, 13 (of 14) biomes, 25 (of 35) biodiversity hotspots and 16 (of 17) megadiverse countries The database contains more than 1% of the total number of all species described, and more than 1% of the described species within many taxonomic groups – including flowering plants, gymnosperms, birds, mammals, reptiles, amphibians, beetles, lepidopterans and hymenopterans The dataset, which is still being added to, is therefore already considerably larger and more representative than those used by previous quantitative models of biodiversity trends and responses The database is being assembled as part of the PREDICTS project (Projecting Responses of Ecological Diversity In Changing Terrestrial Systems – wwwpredictsorguk) We make site-level summary data available alongside this article The full database will be publicly available in 2015

Investigating hypoxia in aquatic environments: diverse approaches to addressing a complex phenomenon

Abstract: In this paper we provide an overview of new knowledge on oxygen depletion (hypoxia) and related phenomena in aquatic systems resulting from the EU-FP7 project HYPOX (“In situ monitoring of oxygen depletion in hypoxic ecosystems of coastal and open seas, and landlocked water bodies”, www.hypox.net). In view of the anticipated oxygen loss in aquatic systems due to eutrophication and climate change, HYPOX was set up to improve capacities to monitor hypoxia as well as to understand its causes and consequences. Temporal dynamics and spatial patterns of hypoxia were analyzed in field studies in various aquatic environments, including the Baltic Sea, the Black Sea, Scottish and Scandinavian fjords, Ionian Sea lagoons and embayments, and Swiss lakes. Examples of episodic and rapid (hours) occurrences of hypoxia, as well as seasonal changes in bottom-water oxygenation in stratified systems, are discussed. Geologically driven hypoxia caused by gas seepage is demonstrated. Using novel technologies, temporal and spatial patterns of watercolumn oxygenation, from basin-scale seasonal patterns to meter-scale sub-micromolar oxygen distributions, were resolved. Existing multidecadal monitoring data were used to demonstrate the imprint of climate change and eutrophication on long-term oxygen distributions. Organic and inorganic proxies were used to extend investigations on past oxygen conditions to centennial and even longer timescales that cannot be resolved by monitoring. The effects of hypoxia on faunal communities and biogeochemical processes were also addressed in the project. An investigation of benthic fauna is presented as an example of hypoxia-devastated benthic communities that slowly recover upon a reduction in eutrophication in a system where naturally occurring hypoxia overlaps with anthropogenic hypoxia. Biogeochemical investigations reveal that oxygen intrusions have a strong effect on the microbially mediated redox cycling of elements. Observations and modeling studies of the sediments demonstrate the effect of seasonally changing oxygen conditions on benthic mineralization pathways and fluxes. Data quality and access are crucial in hypoxia research. Technical issues are therefore also addressed, including the availability of suitable sensor technology to resolve the gradual changes in bottom-water oxygen in marine systems that can be expected as a result of climate change. Using cabled observatories as examples, we show how the benefit of continuous oxygen monitoring can be maximized by adopting proper quality control. Finally, we discuss strategies for state-of-the-art data archiving and dissemination in compliance with global standards, and how ocean observations can contribute to global earth observation attempts.

Chimera States in Networks of Nonlocally Coupled Hindmarsh–Rose Neuron Models

Abstract: We have identified the occurrence of chimera states for various coupling schemes in networks of two-dimensional and three-dimensional Hindmarsh–Rose oscillators, which represent realistic models of neuronal ensembles. This result, together with recent studies on multiple chimera states in nonlocally coupled FitzHugh–Nagumo oscillators, provide strong evidence that the phenomenon of chimeras may indeed be relevant in neuroscience applications. Moreover, our work verifies the existence of chimera states in coupled bistable elements, whereas to date chimeras were known to arise in models possessing a single stable limit cycle. Finally, we have identified an interesting class of mixed oscillatory states, in which desynchronized neurons are uniformly interspersed among the remaining ones that are either stationary or oscillate in synchronized motion.

RD-Connect: An Integrated Platform Connecting Databases, Registries, Biobanks and Clinical Bioinformatics for Rare Disease Research

Abstract: Research into rare diseases is typically fragmented by data type and disease Individual efforts often have poor interoperability and do not systematically connect data across clinical phenotype, genomic data, biomaterial availability, and research/trial data sets Such data must be linked at both an individual-patient and whole-cohort level to enable researchers to gain a complete view of their disease and patient population of interest Data access and authorization procedures are required to allow researchers in multiple institutions to securely compare results and gain new insights Funded by the European Union's Seventh Framework Programme under the International Rare Diseases Research Consortium (IRDiRC), RD-Connect is a global infrastructure project initiated in November 2012 that links genomic data with registries, biobanks, and clinical bioinformatics tools to produce a central research resource for rare diseases

Vertical Flow Constructed Wetlands: Eco-engineering Systems for Wastewater and Sludge Treatment

Abstract: Vertical flow constructed wetlands for wastewater and sludge treatment represent a relatively new and still growing technology. Vertical Flow Constructed Wetlands is the first book to present the state-of-the-art knowledge regarding vertical flow constructed wetlands theory and applications. In this book, you will learn about vertical flow systems with information about application and performance. Vertical Flow Constructed Wetlands also includes information on how different countries are applying the technology, with design guidelines to illustrate best practices worldwide. A focus on water conservation through reuse of treated water showcases the benefit of vertical flow construction, which has greatly increased the attractiveness of the technology in recent years. Features: all state-of-the-art knowledge regarding vertical flow constructed wetlands gathered in one book; a review of various constructed wetland approaches, including information about applications and performance, helps clarify what is currently known about constructed wetland principles and design; and discussion of how to manage the treated wastewater leaving the vertical flow for increasing biodiversity, providing food and habitat for birds, and producing harvestable biomass or crops. It includes case studies of constructed wetlands in developing countries.

Effect of gravity on colloid transport through water-saturated columns packed with glass beads: modeling and experiments.

Abstract: The role of gravitational force on colloid transport in water-saturated columns packed with glass beads was investigated. Transport experiments were performed with colloids (clays: kaolinite KGa-1b, montmorillonite STx-1b). The packed columns were placed in various orientations (horizontal, vertical, and diagonal) and a steady flow rate of Q = 1.5 mL/min was applied in both up-flow and down-flow modes. All experiments were conducted under electrostatically unfavorable conditions. The experimental data were fitted with a newly developed, analytical, one-dimensional, colloid transport model. The effect of gravity is incorporated in the mathematical model by combining the interstitial velocity (advection) with the settling velocity (gravity effect). The results revealed that flow direction influences colloid transport in porous media. The rate of particle deposition was shown to be greater for up-flow than for down-flow direction, suggesting that gravity was a significant driving force for colloid deposition.

Search for Solar Axions by the CERN Axion Solar Telescope with 3He Buffer Gas: Closing the Hot Dark Matter Gap

Abstract: The CERN Axion Solar Telescope has finished its search for solar axions with He-3 buffer gas, covering the search range 0.64 eV less than or similar to ma less than or similar to 1.17 eV. This closes the gap to the cosmological hot dark matter limit and actually overlaps with it. From the absence of excess x rays when the magnet was pointing to the Sun we set a typical upper limit on the axion-photon coupling of g(a gamma) less than or similar to 3.3 x 10(-10) GeV-1 at 95% C.L., with the exact value depending on the pressure setting. Future direct solar axion searches will focus on increasing the sensitivity to smaller values of g(a gamma), for example by the currently discussed next generation helioscope International AXion Observatory.

"Timed Up & Go" : A Screening Tool for Predicting 30-Day Morbidity in Onco-Geriatric Surgical Patients? A Multicenter Cohort Study

Abstract: OBJECTIVE: To determine the predictive value of the "Timed Up & Go" (TUG), a validated assessment tool, on a prospective cohort study and to compare these findings to the ASA classification, an instrument commonly used for quantifying patients' physical status and anesthetic risk. BACKGROUND: In the onco-geriatric surgical population it is important to identify patients at increased risk of adverse post-operative outcome to minimize the risk of over- and under-treatment and improve outcome in this population. METHODS: 280 patients ≥70 years undergoing elective surgery for solid tumors were prospectively recruited. Primary endpoint was 30-day morbidity. Pre-operatively TUG was administered and ASA-classification was registered. Data were analyzed using multivariable logistic regression analyses to estimate odds ratios (OR) and 95% confidence intervals (95%-CI). Absolute risks and area under the receiver operating characteristic curves (AUC's) were calculated. RESULTS: 180 (64.3%) patients (median age: 76) underwent major surgery. 55 (20.1%) patients experienced major complications. 50.0% of patients with high TUG and 25.6% of patients with ASA≥3 experienced major complications (absolute risks). TUG and ASA were independent predictors of the occurrence of major complications (TUG:OR 3.43; 95%-CI = 1.14-10.35. ASA1 vs. 2:OR 5.91; 95%-CI = 0.93-37.77. ASA1 vs. 3&4:OR 12.77; 95%-CI = 1.84-88.74). AUCTUG was 0.64 (95%-CI = 0.55-0.73, p = 0.001) and AUCASA was 0.59 (95%-CI = 0.51-0.67, p = 0.04). CONCLUSIONS: Twice as many onco-geriatric patients at risk of post-operative complications, who might benefit from pre-operative interventions, are identified using TUG than when using ASA.

Heat transfer and natural convection of nanofluids in porous media

Abstract: Natural convection of a nanofluid in a square cavity filled with a porous matrix is numerically investigated using a meshless technique. The Darcy–Brinkman and the energy transport equations are used to describe the nanofluid flow and the heat transfer process in the porous medium as these are generated by heating one of the cavity walls. The role of the nanofluid properties in the cooling performance of the medium and in the relevant heat process is thoroughly investigated. Numerical results are obtained for the stream function, the temperature profile, and the Nusselt number over a wide range of dimensionless quantities (Rayleigh number between 105 and 107, Darcy number between 10−5 and 10−3). The effect of the porous medium in the cooling efficiency of the nanofluidic system is also discussed. Alternative expressions are suggested for the estimation of the effective conductivity and the thermal expansion coefficient of the nanofluid and their effects on the heat transfer problem are investigated. Excellent agreement with experimental data and trends as well as with previously published numerical results for less complicated systems was found.