256 research outputs found

    Mechanical and optical properties of ultralarge flakes of a metal-organic framework with molecular thickness

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    The isolation of 2D-materials is already a success for graphene, graphene oxide, boron nitride and a few clays or metal chalcogenides, however despite the fact that some of them show very interesting physical properties, they lack useful functionalities. Metal-Organic Frameworks (MOFs) are multifunctional materials showing a wide range of physical and chemical properties that can be structurally designed by suitable selection of their building-blocks. This strategy may allow the production of layers with a variety of useful electronic and molecular recognition functionalities. Herein we isolate 2D-MOF flakes with areas of hundreds of square microns and an excellent control of the molecular thickness (from single up to ca. 50 layers). The samples exhibit such good photoluminescence and mechanical properties as to allow free-standing characterization of few layers' flakesThe authors acknowledge financial support from MICINN (MAT2013-46753-C2-1-P and MAT2013-46753-C2-2-P and Consolider CSD2010-00024

    Distribution and Characteristics of Listeria spp. in Pigs and Pork Production Chains in Germany

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    Listeria (L.) monocytogenes is a foodborne pathogen that can cause disease, mainly in elderly, pregnant or immunocompromised persons through consumption of contaminated food, including pork products. It is widespread in the environment and can also be found in asymptomatic carrier animals, for example, in different tissues of pigs. To learn more about their nature, 16 Listeria spp. isolates found in tonsils and intestinal content of pigs and 13 isolates from the slaughterhouse environment were characterized using next-generation sequencing (NGS). A wide distribution of clonal complexes was observed in pigs, as well as in the pork production chain, suggesting multiple sources of entry. Hypervirulent clones were found in pig tonsils, showing the potential risk of pigs as source of isolates causing human disease. The presence of closely related isolates along the production chain suggests a cross-contamination in the slaughterhouse or recontamination from the same source, strengthening the importance of efficient cleaning and disinfection procedures. The phenotypical antimicrobial resistance status of L. monocytogenes isolates was examined via broth microdilution and revealed a low resistance level. Nevertheless, genotypical resistance data suggested multiple resistances in some non-pathogenic L. innocua isolates from pig samples, which might pose a risk of spreading resistances to pathogenic species

    New energy carriers in vehicles and their impact on confined infrastructures Overview of previous research and research needs

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    International audienceThe global warming debate forces the vehicle industry to come up with new environmentally friendly solutions. In 10 years time, or even faster depending on the pressure from different governments in particular in Europe, vehicles will not only use gasoline, diesel and LPG, but also CNG, Hydrogen, ethanol, DME and other bio-fuels, as well as batteries and fuel cells. This quick development and the diversity of new energy carriers can jeopardize the safety in underground infrastructures such as tunnels or car parks. This can cause a major drawback in the adoption of new energy carriers as regulators or operators may prohibit use of these vehicles in underground systems if no new relevant measures will be taken. Unclear situation will also affect the implementation of international policies aiming at reducing the environmental footprint and especially CO2 emission in road traffic. The problem became clear after a workshop with the vehicle industry, tunnel operators, authorities, and safety experts organised in November 2008 by L-surF Services with the support of ITA-COSUF, ECTP and HYSAFE. This workshop demonstrated that the construction sector lacks appropriate design data and tools as well as knowledge to build safe underground infrastructure compatible with a diversity of new and alternative energy carriers. Vehicle industry, infrastructure operators and regulators have not yet addressed this problem. In a first part, an overview of the regulatory situation regarding safety and security of the admission of new energy carriers for vehicles in underground infrastructures is presented. Then, a detailed review of previous relevant research projects performed makes it possible to formulate recommendations in terms of a strategic research & development agenda. The overview shows that it is necessary to develop an integrated risk assessment and management method specific for underground transport systems, metros and hubs in confined spaces taking into account the "emerging risk" aspects

    Chemical composition of laurencia obtusa extract and isolation of a new C15-acetogenin

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    A new C15-acetogenin, sagonenyne (20), exhibiting an unusual single tetrahydropyran ring was isolated from an ethyl acetate extract of Laurencia obtusa collected on the Corsican coastline. Its structure was established by detailed NMR spectroscopic analysis, mass spectrometry, and comparison with literature data. Twenty-three known compounds were identified in the same extract by means of column chromatography steps, using a (13)C-NMR computer aided method developed in our laboratory. In addition to sesquiterpenes, which represent the main chemical class of this extract, diterpenes, sterols, and C15-acetogenins were identified. The crude extract was submitted to a cytotoxicity assay and was particularly active against THP-1 cells, a human leukemia monocytic cell line.info:eu-repo/semantics/publishedVersio

    Population Genetic Structure of Listeria monocytogenes Strains as Determined by Pulsed-Field Gel Electrophoresis and Multilocus Sequence Typing

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    Listeria monocytogenes is a ubiquitous bacterium that may cause the foodborne illness listeriosis. Only a small amount of data about the population genetic structure of strains isolated from food is available. This study aimed to provide an accurate view of the L. monocytogenes food strain population in France. From 1999 to 2014, 1,894 L. monocytogenes strains were isolated from food at the French National Reference Laboratory for L. monocytogenes and classified according to the five risk food matrices defined by the European Food Safety Authority (EFSA). A total of 396 strains were selected on the basis of different pulsed-field gel electrophoresis (PFGE) clusters, serotypes, and strain origins and typed by multilocus sequence typing (MLST), and the MLST results were supplemented with MLST data available from Institut Pasteur, representing human and additional food strains from France. The distribution of sequence types (STs) was compared between food and clinical strains on a panel of 675 strains. High congruence between PFGE and MLST was found. Out of 73 PFGE clusters, the two most prevalent corresponded to ST9 and ST121. Using original statistical analysis, we demonstrated that (i) there was not a clear association between ST9 and ST121 and the food matrices, (ii) serotype IIc, ST8, and ST4 were associated with meat products, and (iii) ST13 was associated with dairy products. Of the two major STs, ST121 was the ST that included the fewest clinical strains, which might indicate lower virulence. This observation may be directly relevant for refining risk analysis models for the better management of food safety. IMPORTANCE This study showed a very useful backward compatibility between PFGE and MLST for surveillance. The results enabled better understanding of the population structure of L. monocytogenes strains isolated from food and management of the health risks associated with L. monocytogenes food strains. Moreover, this work provided an accurate view of L. monocytogenes strain populations associated with specific food matrices. We clearly showed that some STs were associated with food matrices, such as meat, meat products, and dairy products. We opened the way to source attribution modeling in order to quantify the relative importance of the main food matrices

    Closing gaps for performing a risk assessment on Listeria monocytogenes in ready-to-eat (RTE) foods : activity 3, the comparison of isolates from different compartments along the food chain, and from humans using whole genome sequencing (WGS) analysis

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    We would like to thank all the persons and institutes that have provided the project with isolates and accompanying information. Without them, this project would not have been possible. Lin Cathrine T. Brandal, Norwegian Institute of Public Health, Norway Julio Vázquez Moreno and Raquel Abad Torreblanca, Instituto de Salud Carlos III, Spain Marc Lecuit, Institut Pasteur, France Alexandre Leclercq, Institut Pasteur, France Iva Hristova, National Center of Infectious and Parasitic Diseases, Bulgaria Marija Trkov, National Laboratory of Health, Environment and Food, Slovenia Cecilia Jernberg, Public Health Agency of Sweden, Sweden Ariane Pietzka, Austrian Agency for Health and Food Safety, Austria Eelco Franz and Ingrid Friesema, RIVM, The Netherlands Carlo Spanu, University of Sassari Sardinia Ifip, French Institute for Pig and Pork Industry, Maisons-Alfort, France All the NRLs for providing the isolates from the EU baseline study Special thanks to Sylvain Brisse and Alexandra Moura, Institut Pasteur, France, for providing cgMLST data. The authors would also like to thank the EFSA staff members: Maria Teresa da Silva Felicio, Beatriz Guerra, Ernesto Lìebana and Valentina Rizzi as well as the members of the Working Group on Listeria monocytogenes contamination of ready-to-eat foods: Kostas Koutsoumanis, Roland Lindqvist, Moez Sanaa, Panagiotis Skandamis, Niko Speybroek, Johanna Takkinen and Martin Wagner for the support, revisions and suggestions during the development of the present procurement activity and report.Publisher PD

    LiSEQ – whole-genome sequencing of a cross-sectional survey of Listeria monocytogenes in ready-to-eat foods and human clinical cases in Europe

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    Funding information This work was funded by EFSA, contract number C/EFSA/BIOCONTAM/2014/01-CT 1 on “Closing gaps for performing a risk assessment on Listeria monocytogenes in ready-to-eat (RTE) foods: activity 3, the comparison of isolates from different compartments along the food chain, and from humans using whole genome sequencing (WGS) analysis’, EFSA-Q-2014-00 026. Acknowledgements A. P., T. D. and K. G. are affiliated to the National Institute for Health Research – Health Protection Research Unit (NIHR HPRU) in Gastrointestinal Infections at University of Liverpool in partnership with Public Health England, in collaboration with the University of East Anglia, the University of Oxford and the Quadram Institute. A. P., T. D. and K. G. are based at Public Health England. The views expressed are those of the author(s) and not necessarily those of the NHS, the NIHR, the Department of Health or Public Health England.Peer reviewedPublisher PD

    Effets Des Technologies Membranaires Sur Les Caracteristiques Physicochimiques Des Extraits De Fruits De La Passion (Passiflora Edulis)

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    The passion fruit or grenadilla is usually consumed in the form of juice and its pleasant intensive aroma and flavor make it an attractive element for the food industry. The objective of the present work is to determine the effects of membrane technologies such as tangential microfiltration and reverse osmosis on the physicochemical characteristics of passion fruit extracts. The characteristics of the various extracts were determined according to conventional methods. In addition, statistical methods were applied to the data collected in order to determine the effects of membrane technologies. The results showed a yield of 89.33% for the extraction of the microfiltered juice and a volume reduction factor of 16.75 for the concentrate. In addition, the microfiltration-concentration process significantly (p <0.05) influenced the physicochemical parameters of the extracts produced. Thus, tangential microfiltration made it possible to clarify the crude extract by changing from a turbidity of 89.23 ± 1.71 to 0.72 ± 0.02 NTU. It has also resulted in a significant decrease in pH and flavonoids contents. Principal component analysis confirmed the existence of differences between the extracts produced despite the various correlations between their characteristics. It revealed that the JB and CMFT extracts are characterized by their high pH and low density. On the other hand, the COI extract is characterized by its brix degree, viscosity, conductivity and high vitamin C content. In addition, reverse osmosis has the advantage of concentrating the compounds of interest of clarified juice with a concentration factor ranging from 2.15 to 9.39

    Proyecto de creación de aplicación Pet & Care

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    Nuestro emprendimiento presenta la elaboración de una aplicación que une a las grandes veterinarias de Lima con las personas que necesiten de información y atención de los expertos en animales. A partir de los análisis realizados en entrevistas y conversaciones situacionales, aplicadas a personas que tienen una mascota en casa, hemos detectado factores que determinan el uso de la tecnología para encontrar lo que se requiere, en ese momento por lo que llegamos a definir lo siguiente: La principal ventaja es contar con la comunicación necesaria para poder atender las necesidades y emergencias que ocurren en todo momento. Los dueños de los animales necesitan de especialistas para poder atender las necesidades y emergencias que ocurren todos los días. Hoy en día, recurren a la tecnología para poder encontrar una solución, es por ello, que las redes sociales y los aplicativos se hayan convertido en un medio indispensable para poder encontrar servicios y productos que requieren sus mascotas. Lograr el desarrollar el aplicativo es un objetivo importante para el equipo ya que somos conscientes que es un mercado que aún tiene grandes necesidades. Por otro lado, el equipo también constató, mediante entrevistas a profundidad, que resultaría cómodo e interesante encontrar en un programa información de diferentes especialidades y Petshop para mascotas.Our venture presents the development of an application that unites people with experts that can offer exceptional quality of attention from the analyzes carried out in interviews and situational conversations, applied to people who have a pet at home, we have detected factors that determine the use of technology to find what is required, meanwhile, for which we came to define the following: The main advantage is having the necessary communication to provide the needs and emergencies for pets that occur at all times. Most veterinarians treat illnesses and injuries in veterinary clinics. Nowdays, owners are able to use technology to find a solution, which is why social networks and applications have become an indispensable means to find services and products that their pets require. Achieving the development of that application is an important objective for the team since we are aware that it is a market that still has great needs. On the other hand, the team also found, through in-depth interviews, that it would be convenient and interesting to find information on different specialties and Pet shop for pets in a program.Trabajo de investigació
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