41 research outputs found

    System Level Analysis of Millimetre-wave GaN-based MIMO Radar for Detection of Micro Unmanned Aerial Vehicles

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    The detection of Unmanned Aerial Vehicles (UAVs) of micro/nano dimensions, is becoming a hot topic, due to their large diffusion, and represents a challenging task from both the system architecture and components point of view. The Frequency Modulated Continuous Wave (FMCW) radar architecture in a Multi-Input Multi-Output configuration has been identified as the most suitable solution for this purpose, due to both its inherent short-range detection capability and compact implementation. This paper describes the operation and technology challenges inherent to the development of a millimeter-wave FMCW MIMO radar for small UAVs detection. In particular it analyzes the sub-systems specifications and the expected system performance with respect to a chip set designed and developed in GaN at 37.5 GHz applications

    Development of an in vitro cell system from zebrafish suitable to study bone cell differentiation and extracellular matrix mineralization

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    Mechanisms of bone formation and skeletal development have been successfully investigated in zebrafish using a variety of in vivo approaches, but in vitro studies have been hindered due to a lack of homologous cell lines capable of producing an extracellular matrix (ECM) suitable for mineral deposition. Here we describe the development and characterization of a new cell line termed ZFB1, derived from zebrafish calcified tissues. ZFB1 cells have an epithelium-like phenotype, grow at 28 degrees C in a regular L-15 medium supplemented with 15% of fetal bovine serum, and are maintained and manipulated using standard methods (e.g., trypsinization, cryopreservation, and transfection). They can therefore be propagated and maintained easily in most cell culture facilities. ZFB1 cells show aneuploidy with 2n=78 chromosomes, indicative of cell transformation. Furthermore, because DNA can be efficiently delivered into their intracellular space by nucleofection, ZFB1 cells are suitable for gene targeting approaches and for assessing gene promoter activity. ZFB1 cells can also differentiate toward osteoblast or chondroblast lineages, as demonstrated by expression of osteoblast- and chondrocyte-specific markers, they exhibit an alkaline phosphatase activity, a marker of bone formation in vivo, and they can mineralize their ECM. Therefore, they represent a valuable zebrafish-derived in vitro system for investigating bone cell differentiation and extracellular matrix mineralization.FISHCELL project [PTDC/MAR/105313/2008]; Portuguese Science and Technology Foundation (FCT); European Regional Development Fund (ERDF) through the COMPETE Program; National Fund through FCT [PEst-C/MAR/LA0015/2011]; FCT [SFRH/BPD/39189/2007]; Association of European Marine Biological Laboratories through the ASSEMBLE project [FP7/227799]info:eu-repo/semantics/publishedVersio

    Opportunities for Energy Demand and Carbon Emissions Reduction in the Chemicals Sector

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    The opportunities and challenges to reducing industrial energy demand and carbon dioxide (CO2) emissions in the Chemicals sector are evaluated with a focus is on the situation in the United Kingdom (UK), although the lessons learned are applicable across much of the industrialised world. This sector can be characterised as being quite heterogeneous, and as sitting on the boundary between energy-intensive (EI) and non-energy-intensive (NEI) industrial sectors. Currently-available technologies will lead to further, short-term energy and CO2 emissions savings in chemicals processing, but the prospects for the commercial exploitation of innovative technologies by mid-21st century are far more speculative. The chemicals sector has long been the largest owner of generating plant in UK industry. Most generation is from CHP plant with significant amounts of excess electricity exported to the grid or other industrial sectors. Special care was taken not to ‘double count’ auto-generation and grid decarbonisation; so that the relative contributions to decarbonisations of each was accounted for separately. There are a number of non-technological barriers to the take-up of such technologies going forward. Consequently, the transition to a low carbon future in UK industry by 2050 will exhibit rather large uncertainties. The attainment of significant falls in carbon emissions over this period will depends critically on the adoption of a small number of key technologies [e.g., carbon capture and storage (CCS), energy efficiency techniques, and bioenergy], alongside a decarbonisation of the electricity supply

    Enhanced transfection of cell lines from Atlantic salmon through nucoleofection and antibiotic selection

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    Background Cell lines from Atlantic salmon kidney have made it possible to culture and study infectious salmon anemia virus (ISAV), an aquatic orthomyxovirus affecting farmed Atlantic salmon. However, transfection of these cells using calcium phosphate precipitation or lipid-based reagents shows very low transfection efficiency. The Amaxa Nucleofector technology™ is an electroporation technique that has been shown to be efficient for gene transfer into primary cells and hard to transfect cell lines. Findings Here we demonstrate, enhanced transfection of the head kidney cell line, TO, from Atlantic salmon using nucleofection and subsequent flow cytometry. Depending on the plasmid promoter, TO cells could be transfected transiently with an efficiency ranging from 11.6% to 90.8% with good viability, using Amaxa's cell line nucleofector solution T and program T-20. A kill curve was performed to investigate the most potent antibiotic for selection of transformed cells, and we found that blasticidin and puromycin were the most efficient for selection of TO cells. Conclusions The results show that nucleofection is an efficient way of gene transfer into Atlantic salmon cells and that stably transfected cells can be selected with blasticidin or puromycin

    Comparison of four different colorimetric and fluorometric cytotoxicity assays in a zebrafish liver cell line

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    Background: A broad spectrum of cytotoxicity assays is currently used in the fields of (eco)toxicology and pharmacology. To choose an appropriate assay, different parameters like test compounds, detection mechanism, specificity, and sensitivity have to be considered. Furthermore, tissue or cell line can influence test performance. For zebrafish (Danio rerio), as emerging model organism, cell lines are now increasingly used, but few studies examined cytotoxicity in these cell systems. Therefore, we compared four cytotoxicity assays in the zebrafish liver cell line, ZFL, to test four differently acting model compounds. The tests comprised two colorimetric assays (MTT assay using 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide, and the LDH assay detecting lactate dehydrogenase activity) and two fluorometric assays (alamarBlue® using resazurin, and CFDA-AM based on 5-carboxyfluorescein diacetate acetoxymethyl ester). Model compounds were the pharmaceutical Tamoxifen, its metabolite 4-Hydroxy-Tamoxifen, the fungicide Flusilazole and the polycyclic aromatic hydrocarbon Benzo[a]pyrene. Results: All four assays performed well in the ZFL cells and led to reproducible dose-response curves for all test compounds. Effective concentrations causing 10% or 50% loss of cell viability (EC10 and EC50 values) varied by a maximum factor of 7.0 for the EC10 values and a maximum factor of 1.8 for the EC50 values. The EC values were not statistically different between the four assays, which is due to the assessed unspecific effects of the compounds. However, most often, the MTT assay and LDH assay showed the highest and lowest EC values, respectively. Nevertheless, the LDH assay showed the highest intra- and inter-assay variabilities and the lowest signal-to-noise ratios. In contrast to MTT, the other three assays have the advantage of being non-destructive, easy to handle, and less time consuming. Furthermore, AB and CFDA-AM can be combined on the same set of cells without damaging the cells, allowing later on their use for the investigation of other endpoints. Conclusions: We recommend the alamarBlue and CFDA-AM assays for cytotoxicity assessment in ZFL cells, which can be applied either singly or combined.JRC.H.5-Rural, water and ecosystem resource

    Mitogenic activity from trout embryos.

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    In vivo assay for the developmental competence of embryo-derived zebrafish cell lines

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    We have produced chimeric zebrafish embryos by transplanting permanent embryo-derived cell lines into blastula-stage embryos. Furthermore, we have established a fluorescent in vivo assay to monitor the developmental effects and fate of such transplanted cells using confocal laser scanning microscopy. All zebrafish embryonic cell lines tested (ZEM2, ZF13, ZF29, ZF29-C1, and ZF29-C2), when introduced as small groups of less than 20 cells, survived at least several days after transplantation, whereas a control cell line isolated from adult goldfish fin (CAR) soon displayed necrosis and cell death. The ZEM2 cells, isolated from blastula-stage embryos, appeared to contribute to different germ layers, whereas the ZF29 cells derived from 22- to 28-somite embryos differentiated mainly into mesenchymal-like cells in vivo. Interestingly, when transplanted as groups of 50 to 150 cells, the ZF29 cells were capable of profound developmental effects, the most prominent being the induction of ectopic notochord and neural tissue, sometimes resulting in a partial secondary body axis. This effect was observed more frequently when cells were transplantated into young blastula-stage embryos, and occurred mostly in the prechordal head region of the embryo. In contrast, ZEM2 cells never induced ectopic tissues after transplantation. The methods and results described here will be useful in future efforts to select and characterize putative embryonic stem cell lines from zebrafish
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