81 research outputs found

    Mitigating the effects of HIV/AIDs in small-scale farming

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    Ecological relevance of shipwrecks in the North Sea

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    This paper reports on observations made during wreck dive expeditions in 2010-2012, in order to investigate the ecological relevance of shipwrecks on the Dutch Continental Shelf (DCS). Shipwrecks are biodiversity hotspots. The number of species recorded on shipwrecks is similar to the number of species found in soft bottoms of the entire DCS. The soft substrates, however, represent a vastly larger habitat on the DCS than the shipwrecks. Amongst many other taxa, juvenile and large Atlantic cod, linear skeleton shrimp, goldsinny wrasses and leopard spotted gobies were found in the shipwreck habitats. The presence of these important species and their absence from many other habitats, illustrate that shipwrecks function as key habitats, nurseries, and refugia that are rare or absent anywhere else in the Netherlands

    Marine fauna of hard substrata of the Cleaver Bank and Dogger Bank

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    As most of the sea bottom in the Dutch part of the North Sea consists of sand, marine fauna that live in association with hard substrates are rarely monitored. We report here on the results of a species inventory in June 2011 done by scuba-diving while focusing on a wreck on the Dogger Bank and on rocky bottoms on the Cleaver Bank. This resulted in various new records of species for the Dutch part of the North Sea. This result appeared for a large part linked to the added value of monitoring with scuba-divers. It is therefore concluded that scuba-divers should be used in addition to the more traditional monitoring methods in which dredges and grabs are used, if one aims at getting an accurate view of the biodiversity present in marine regions like the North Sea

    Ionophoric properties of a tetra-tetrazole functionalised calix[4]arene

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    © 2015 Taylor & Francis. The synthesis and characterisation of p-t-butylcalix[4]arene functionalised at the lower rim with four tetrazole moieties is reported. The macrocycle is found to be a poorer ionophore for lanthanoid cations than the bis-tetrazole-substituted analogue. Solution-phase photophysical studies strongly suggested that the cations interacted only weakly with the calixarene ligand. A mixed sodium/triethylammonium salt of the calixarene ligand was crystallised in the presence of lanthanoid cations and structurally characterised. Strong intramolecular interactions are hypothesised to be the cause of the observed behaviour

    In vivo [64Cu]CuCl2 PET imaging reveals activity of Dextran-Catechin on tumor copper homeostasis

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    Given the strong clinical evidence that copper levels are significantly elevated in a wide spectrum of tumors, copper homeostasis is considered as an emerging target for anticancer drug design. Monitoring copper levels in vivo is therefore of paramount importance when assessing the efficacy of copper-targeting drugs. Herein, we investigated the activity of the copper-targeting compound Dextran-Catechin by developing a [64Cu]CuCl2 PET imaging protocol to monitor its effect on copper homeostasis in tumors. Methods: Protein expression of copper transporter 1 (CTR1) in tissue microarrays representing 90 neuroblastoma patient tumors was assessed by immunohistochemistry. Western blotting analysis was used to study the effect of Dextran-Catechin on the expression of CTR1 in neuroblastoma cell lines and in tumors. A preclinical human neuroblastoma xenograft model was used to study anticancer activity of Dextran-Catechin in vivo and its effect on tumor copper homeostasis. PET imaging with [64Cu]CuCl2 was performed in such preclinical neuroblastoma model to monitor alteration of copper levels in tumors during treatment. Results: CTR1 protein was found to be highly expressed in patient neuroblastoma tumors by immunohistochemistry. Treatment of neuroblastoma cell lines with Dextran-Catechin resulted in decreased levels of glutathione and in downregulation of CTR1 expression, which caused a significant decrease of intracellular copper. No changes in CTR1 expression was observed in normal human astrocytes after Dextran-Catechin treatment. In vivo studies and PET imaging analysis using the neuroblastoma preclinical model revealed elevated [64Cu]CuCl2 retention in the tumor mass. Following treatment with Dextran-Catechin, there was a significant reduction in radioactive uptake, as well as reduced tumor growth. Ex vivo analysis of tumors collected from Dextran-Catechin treated mice confirmed the reduced levels of CTR1. Interestingly, copper levels in blood were not affected by treatment, demonstrating potential tumor specificity of Dextran-Catechin activity. Conclusion: Dextran-Catechin mediates its activity by lowering CTR1 and intracellular copper levels in tumors. This finding further reveals a potential therapeutic strategy for targeting copper-dependent cancers and presents a novel PET imaging method to assess patient response to copper-targeting anticancer treatments

    Natuurwaarden Borkumse Stenen: project aanvullende beschermde gebieden

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    In dit rapport wordt de bodemfauna in het gebied ‘Borkumse Stenen’ beschreven. Het gebied ‘Borkumse Stenen’ ligt ten noorden van Schiermonnikoog en grenst aan de zuidzijde aan het Nederlandse Natura 2000-gebied Noordzeekustzone en aan de oostzijde aan het Duitse Natura 2000-gebied ‘Borkum Riffgrund’, dat o.a. vanwege de aanwezigheid van habitattype H1170 (‘riffen’) is aangewezen

    Digital strategies to a local cultural tourism development: Project e-Carnide

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    Digital humanities and smart economy strategies are being seen as an important link between tourism and cultural heritage, as they may contribute to differentiate the audiences and to provide different approaches. Carnide is a peripheral neighbourhood of Lisbon with an elderly population, visible traces of rurality, and strong cultural and religious traditions. The academic project e-Carnide concerns its tangible and intangible cultural heritage and the data dissemination through a website and a mobile app, with textual and visual information. The project aims to analyse the impact of technological solutions on cultural tourism development in a sub-region, involving interdisciplinary research in heritage, history of art, ethnography, design communication and software engineering and the collaboration between the university and local residents in a dynamic and innovative way. Framed by a theoretical approach about the role of smart economy for the cultural tourism development in peripheral areas, this paper focuses on a case study, dealing with documents, interviews and observations, in order to understand how the e-Carnide project evolves. The study comprises an analysis about the strengths, weaknesses, opportunities and threats (SWOT analysis) of the project in view to realize its social and cultural implications and to appreciate how it can be applied in other similar and enlarged projects. Results of the research indicates that the new technological strategies can promote the involvement of the population in the knowledge of its own heritage as a factor of cultural and creative tourism development centred on an authentic and immersive experience of the places

    Lanthanoid “Bottlebrush” Clusters: Remarkably Elongated Metal-Oxo Core Structures with Controllable Lengths

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    Large metal-oxo clusters consistently assume spherical or regular polyhedral morphologies rather than high-aspect-ratio structures. Access to elongated core structures has now been achieved by the reaction of lanthanoid salts with a tetrazole-functionalized calixarene in the presence of a simple carboxylate coligand.The resulting Ln19 and Ln12 clusters are constructed from apex-fused Ln5O6 trigonal bipyramids and are formed consistently under a range of reaction conditions and reagent ratios. Altering the carboxylate coligandstructure reliably controls the cluster length, giving access to a new class of rod-like clusters of variable length

    Capturing threshold responses of marine benthos along gradients of natural and anthropogenic change

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    1. Ecologists and managers need to understand what types of communities emerge with continued human alterations to ecosystems against a background of natural change. Both natural and anthropogenic drivers are well known to affect organisms’ distributions; however, it often remains unclear where along a range of environmental and anthropogenic gradients important compositional community changes occur. 2. We used a big-data approach, including over 175,000 presence records of benthic genera for the North Sea, to identify environmental (bed shear stress, sediment grain size, temperature) and anthropogenic parameters (trawling effort) driving benthic community composition over a 21-year period. We applied a Gradient Forest analysis, based on Random Forests, to estimate the locations and importance of thresholds where small cumulative increases in the predictors drive a much greater change in genus composition than would be expected from linear effects. 3. Shear stress was the most important predictor of benthic community composition. Trawling effort, temperature gradients and sediment grain size were of intermediate importance. This corroborates that current and wave effects (typically associated with seabed substrate types) are primary determinants of benthic communities. 4. Our results suggest that a genus composition threshold for both infauna and epifaunal benthic communities is crossed when the seafloor is trawled as little as once every 4 years. Higher trawling levels corresponded with gradual compositional change without obvious thresholds, which would be consistent with chronic fishing in the North Sea over the last two centuries having caused persistent, long-term changes in ecosystem structure and functioning. This was corroborated by the large-scale spatial patterns of benthic community composition undergoing limited temporal changes during the 21-year study period. 5. Synthesis and applications. Although well established in theory, threshold effects are poorly validated in the field. We generated new information on multi-organism responses to environmental change at the scale of a continental shelf ecosystem and over a multi-decadal time period. This will help pure and applied scientists better understand the conditions under which community thresholds are crossed and provide environmental managers with empirical evidence that is expected to reduce uncertainty regarding decisions on the protection and sustainable use of the marine environment
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