87 research outputs found

    Alpha induced reaction cross section measurements on 162Er for the astrophysical γ process

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    Funding Details: NSF, National Science Foundation. ©2014 Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/3.0/). Funded by SCOAP3The cross sections of the Er162(α,γ)Yb166 and Er162(α,n)Yb165 reactions have been measured for the first time. The radiative alpha capture reaction cross section was measured from Ec.m.=16.09MeV down to Ec.m.=11.21MeV, close to the astrophysically relevant region (which lies between 7.8 and 11.48 MeV at 3 GK stellar temperature). The Er162(α,n)Yb165 reaction was studied above the reaction threshold between Ec.m.=12.19 and 16.09MeV. The fact that the Er162(α,γ)Yb166 cross sections were measured below the (α,n) threshold at first time in this mass region opens the opportunity to study directly the α-widths required for the determination of astrophysical reaction rates. The data clearly show that compound nucleus formation in this reaction proceeds differently than previously predicted. © 2014 Elsevier B.V.Peer reviewedFinal Published versio

    Capillary-Driven Pumping for Passive Degassing and Fuel Supply in Direct Methanol Fuel Cells

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    Abstract In this paper we present a new concept of creating and using capillary pressure gradients for passive degassing and passive methanol supply in direct methanol fuel cells (DMFCs). An anode flow field consisting of parallel tapered channels structures is applied to achieve the passive supply mechanism. The flow is propelled by the surface forces of deformed CO 2 bubbles, generated as a reaction product during DMFC operation. This work focuses on studying the influence of channel geometry and surface properties on the capillary-induced liquid flow rates at various bubbly gas flow rates. Besides the aspect ratios and opening angles of the tapered channels, the static contact angle as well as the effect of contact angle hysteresis has been identified to significantly influence the liquid flow rates induced by capillary forces at the bubble menisci. Applying the novel concept, we show that the liquid flow rates are up to thirteen times higher than the methanol oxidation reaction on the anode requires. Experimental results are presented that demonstrate the continuous passive operation of a DMFC for more than 15 h

    Tuning the 3D microenvironment of reprogrammed tubule cells enhances biomimetic modeling of polycystic kidney disease

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    Renal tubular cells frequently lose differentiation markers and physiological properties when propagated in conventional cell culture conditions. Embedding cells in 3D microenvironments or controlling their 3D assembly by bioprinting can enhance their physiological properties, which is beneficial for modeling diseases in vitro. A potential cellular source for modeling renal tubular physiology and kidney diseases in vitro are directly reprogrammed induced renal tubular epithelial cells (iRECs). iRECs were cultured in various biomaterials and as bioprinted tubular structures. They showed high compatibility with the embedding substrates and dispensing methods. The morphology of multicellular aggregates was substantially influenced by the 3D microenvironment. Transcriptomic analyses revealed signatures of differentially expressed genes specific to each of the selected biomaterials. Using a new cellular model for autosomal-dominant polycystic kidney disease, Pkd1/^{-/-} iRECs showed disrupted morphology in bioprinted tubules and a marked upregulation of the Aldehyde dehydrogenase 1a1 (Aldh1a1). In conclusion, 3D microenvironments strongly influence the morphology and expression profiles of iRECs, help to unmask disease phenotypes, and can be adapted to experimental demands. Combining a direct reprogramming approach with appropriate biomaterials will facilitate construction of biomimetic kidney tubules and disease models at the microscale

    Soil seed bank of the invasive Robinia pseudoacacia in planted Pinus nigra stands

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    Pinus nigra and Robinia pseudoacacia are exotic trees used for afforestation in Hungary. Pinus nigra was non-invasive, however R. pseudoacacia escaped from cultivation and invaded several vegetation types including pine plantations. It has recently been planned to cut P. nigra plantations and replace them by native tree stands, especially in nature reserves. The scattered presence of R. pseudoacacia specimens in pine stands might place constraints on planned tree replacement because of their vegetative resprouting and recolonization from an established seed bank. The aim of this study was to investigate the soil seed bank under the canopy of solitary R. pseudoacacia specimens found in P. nigra plantations. Altogether 250 soil samples were collected from the 0–6 and 6–12 cm soil layers under solitary Robinia trees of varying ages (with basal areas between 62.4 and 1089.3 cm2). Seeds were separated by sieving then scarified and germinated. Seed bank density ranged between 640 and 2285 seedsm–2 with an average distribution of 82.7% and 17.3% in the upper and lower soil layer, respectively. Total density of the seed bank and also the seed bank ratio of the lower soil layer increased with tree age. The accumulated seed bank of R. pseudoacacia should be considered in the careful planning of tree replacement operations in Pinus nigra stands

    Contributors

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    The Andrew W. Mellon Foundation and the National Library of Estonia organized a Conference on Union Catalogs which took place in Tallinn, in the National Library of Estonia on October 17–19, 2002. The Conference presented and discussed analytical papers dealing with various aspects of designing and implementing union catalogs and shared cataloging systems as revealed through the experiences of Eastern European, Baltic and South African research libraries. Here you can find the texts of the conference papers and the list of contributors and participants.The Andrew W. Mellon Foundation and the National Library of Estonia organized a Conference on Union Catalogs which took place in Tallinn, in the National Library of Estonia on October 17–19, 2002. The Conference presented and discussed analytical papers dealing with various aspects of designing and implementing union catalogs and shared cataloging systems as revealed through the experiences of Eastern European, Baltic and South African research libraries. Here you can find the texts of the conference papers and the list of contributors and participants

    On the reproducibility of extrusion-based bioprinting: round robin study on standardization in the field

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    The outcome of three-dimensional (3D) bioprinting heavily depends, amongst others, on the interaction between the developed bioink, the printing process, and the printing equipment. However, if this interplay is ensured, bioprinting promises unmatched possibilities in the health care area. To pave the way for comparing newly developed biomaterials, clinical studies, and medical applications (i.e. printed organs, patient-specific tissues), there is a great need for standardization of manufacturing methods in order to enable technology transfers. Despite the importance of such standardization, there is currently a tremendous lack of empirical data that examines the reproducibility and robustness of production in more than one location at a time. In this work, we present data derived from a round robin test for extrusion-based 3D printing performance comprising 12 different academic laboratories throughout Germany and analyze the respective prints using automated image analysis (IA) in three independent academic groups. The fabrication of objects from polymer solutions was standardized as much as currently possible to allow studying the comparability of results from different laboratories. This study has led to the conclusion that current standardization conditions still leave room for the intervention of operators due to missing automation of the equipment. This affects significantly the reproducibility and comparability of bioprinting experiments in multiple laboratories. Nevertheless, automated IA proved to be a suitable methodology for quality assurance as three independently developed workflows achieved similar results. Moreover, the extracted data describing geometric features showed how the function of printers affects the quality of the printed object. A significant step toward standardization of the process was made as an infrastructure for distribution of material and methods, as well as for data transfer and storage was successfully established

    On the reproducibility of extrusion-based bioprinting: round robin study on standardization in the field

    Get PDF
    The outcome of three-dimensional (3D) bioprinting heavily depends, amongst others, on the interaction between the developed bioink, the printing process, and the printing equipment. However, if this interplay is ensured, bioprinting promises unmatched possibilities in the health care area. To pave the way for comparing newly developed biomaterials, clinical studies, and medical applications (i.e. printed organs, patient-specific tissues), there is a great need for standardization of manufacturing methods in order to enable technology transfers. Despite the importance of such standardization, there is currently a tremendous lack of empirical data that examines the reproducibility and robustness of production in more than one location at a time. In this work, we present data derived from a round robin test for extrusion-based 3D printing performance comprising 12 different academic laboratories throughout Germany and analyze the respective prints using automated image analysis (IA) in three independent academic groups. The fabrication of objects from polymer solutions was standardized as much as currently possible to allow studying the comparability of results from different laboratories. This study has led to the conclusion that current standardization conditions still leave room for the intervention of operators due to missing automation of the equipment. This affects significantly the reproducibility and comparability of bioprinting experiments in multiple laboratories. Nevertheless, automated IA proved to be a suitable methodology for quality assurance as three independently developed workflows achieved similar results. Moreover, the extracted data describing geometric features showed how the function of printers affects the quality of the printed object. A significant step toward standardization of the process was made as an infrastructure for distribution of material and methods, as well as for data transfer and storage was successfully established

    Information professionals and copyright literacy: a multinational study

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    Purpose: The purpose of this paper is to present findings from a multinational survey on copyright literacy of specialists from libraries and other cultural institutions. Design/methodology/approach: This paper is based on a multinational survey of copyright literacy competencies of Library and Information Science (LIS) professionals and those who work in the cultural heritage sector (archives and museums), conducted in 13 countries, namely Bulgaria (BG), Croatia (CR), Finland (FI), France (FR), Hungary (HU), Lithuania (LT), Mexico (MX), Norway (NO), Portugal (PT), Romania (RO), Turkey (TR), UK and USA in the period July 2013-March 2015. An online survey instrument was developed in order to collect data from professionals regarding their familiarity with, knowledge and awareness of, and opinions on copyright-related issues. Findings: Findings of this study highlight gaps in existing knowledge of copyright, and information about the level of copyright literacy of LIS and cultural sector professionals. Also attitudes toward copyright learning content in academic education and continuing professional development training programs are investigated. Originality/value: This study aimed to address a gap in the literature by encompassing specialists from the cultural institutions in an international comparative context. The paper offers guidance for further understanding of copyright in a wider framework of digital and information literacy; and for the implementation of copyright policy, and the establishment of copyright advisor positions in cultural institutions. The recommendations support a revision of academic and continuing education programs learning curriculum and methods

    Global Geographic Distribution and Host Range of Fusarium circinatum, the Causal Agent of Pine Pitch Canker

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    Fusarium circinatum, the causal agent of pine pitch canker (PPC), is currently one of the most important threats of Pinus spp. globally. This pathogen is known in many pine-growing regions, including natural and planted forests, and can affect all life stages of trees, from emerging seedlings to mature trees. Despite the importance of PPC, the global distribution of F. circinatum is poorly documented, and this problem is also true of the hosts within countries that are affected. The aim of this study was to review the global distribution of F. circinatum, with a particular focus on Europe. We considered (1) the current and historical pathogen records, both positive and negative, based on confirmed reports from Europe and globally; (2) the genetic diversity and population structure of the pathogen; (3) the current distribution of PPC in Europe, comparing published models of predicted disease distribution; and (4) host susceptibility by reviewing literature and generating a comprehensive list of known hosts for the fungus. These data were collated from 41 countries and used to compile a specially constructed geo-database. A review of 6297 observation records showed that F. circinatum and the symptoms it causes on conifers occurred in 14 countries, including four in Europe, and is absent in 28 countries. Field observations and experimental data from 138 host species revealed 106 susceptible host species including 85 Pinus species, 6 non-pine tree species and 15 grass and herb species. Our data confirm that susceptibility to F. circinatum varies between different host species, tree ages and environmental characteristics. Knowledge on the geographic distribution, host range and the relative susceptibility of different hosts is essential for disease management, mitigation and containment strategies. The findings reported in this review will support countries that are currently free of F. circinatum in implementing effective procedures and restrictions and prevent further spread of the pathogen
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