296 research outputs found

    Cloning and sequence analysis of benzo-a-pyreneinducible cytochrome P450 1A in Nile tilapia (Oreochromis niloticus)

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    Polycyclic aromatic hydrocarbons (PAHs), dioxins, dibenzofurans and polychlorinated biphenyls (PCBs) present in polluted environment induce cytochrome P4501A (CYP1A) isozyme in fish which inturn results in a marked increased production of carcinogenic metabolites. The induction of hepatic CYP1A in fish by certain classes of chemicals has been suggested as an early warning system, a “mostsensitive biological response” for assessing environmental contamination conditions. This has implications for human fish consumption as well as for the health status of aquatic organisms.Considering the importance of Oreochromis niloticus fish as a laboratory animal, the common CYP1A sequence was determined from cDNA and genomic DNA after intraperitoneal injection with benzo-apyrene (BaP). The full-length cDNA was 2530 bp long and contained an open reading frame of 1566 bp encoding a protein of 521 amino acids and a stop codon. The sequence exhibited 5' and 3' noncodingregions of 134 and 830 bp, respectively. The deduced amino acid sequence of O. niloticus CYP1A shows similarities of 80.5, 79.3, 79.1, 77.8, 77.6, 74.3, 72.4, 77.2, 71.8, 70.7 and 50.8% with Europeanflounder CYP1A, scup CYP1A, killifish CYP1A, butterfly fish CYP1A, European sea bass CYP1A, rainbow trout CYP1A, Japanese eel CYP1A, toad fish CYP1A, European eel CYP1A, red sea bream CYP1A and common carp CYP1A, respectively. The phylogenetic tree based on the amino acid sequences clearly shows tilapia CYP1A and killifish CYP1A to be more closely related to each other than to the other CYP1A subfamilies. Sequence analysis of 3727 bp of genomic DNA showed that the clone obtained was the structural gene of CYP1A which consists of seven exons and six introns, the initiation codon was not found in the first exon but in the second one as was reported for the CYP1A genes of fish and mammals

    Development and application of a real-time quantitative PCR assay for determining expression of benzo-apyrene- Inducible cytochrome P450 1A in Nile tilapia (Oreochromis niloticus)

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    Cytochrome P4501A’s (CYP1A) constitute a ubiquitous family of proteins associated with the detoxification of organic compounds such as PCB (polychlorinated biphenyl), PAH (polyaromatic hydrocarbons) and dioxin. These compounds are documented to induce the CYP1A gene in a variety of tissues of many fish species. Consequently, changes in CYP1A gene expression have been used as a biomarker for contaminant exposure in fish populations using a variety of techniques. Of all of thesemethods, quantitative PCR appears to be the most sensitive. It has been used to assess impact of environmental pollution in marine ecosystems using different fish models. Subsequently, for measuring benzo-a-pyrene (BaP) induction of CYP1A mRNA in different organs of tilapia (Oreochromis niloticus), ribosomal protein large P0-like protein (RPLP0-like protein) and -actin genes as internal controls were selected based on previous studies to assess their expression variability. Real-time polymerase chainreaction (real-time PCR) analysis of liver, intestine, gills and kidney revealed a distinct induced expression in liver and intestine (127.1 and 79.3 in liver, 26 and 56.1 in intestine using RPLP0 and -actin genes respectively as internal controls) with no detectable expression in the other organs studied

    A review of size and geometrical factors influencing resonant frequencies in metamaterials

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    Although metamaterials and so-called left-handed media have originated from theoretical considerations, it is only by their practical fabrication and the measurement of their properties that they have gained credibility and can fulfil the potential of their predicted properties. In this review we consider some of the more generally applicable fabrication methods and changes in geometry as they have progressed, exhibiting resonant frequencies ranging from radio waves to the visible optical region

    Ultrahigh Surface Area Three-Dimensional Porous Graphitic Carbon from Conjugated Polymeric Molecular Framework

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    Porous graphitic carbon is essential for many applications such as energy storage devices, catalysts, and sorbents. However, current graphitic carbons are limited by low conductivity, low surface area, and ineffective pore structure. Here we report a scalable synthesis of porous graphitic carbons using a conjugated polymeric molecular framework as precursor. The multivalent cross-linker and rigid conjugated framework help to maintain micro- and mesoporous structures, while promoting graphitization during carbonization and chemical activation. The above unique design results in a class of highly graphitic carbons at temperature as low as 800 ??C with record-high surface area (4073 m2 g-1), large pore volume (2.26 cm-3), and hierarchical pore architecture. Such carbons simultaneously exhibit electrical conductivity >3 times more than activated carbons, very high electrochemical activity at high mass loading, and high stability, as demonstrated by supercapacitors and lithium-sulfur batteries with excellent performance. Moreover, the synthesis can be readily tuned to make a broad range of graphitic carbons with desired structures and compositions for many applications.clos

    Analysis of parcel-based image classification methods for monitoring the activities of the Land Bank of Galicia (Spain)

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    [EN] The abandonment of agricultural plots entails a low economic productivity of the land and a higher vulnerability to wildfires and degradation of affected areas. In this sense, the local government of Galicia is promoting new methodologies based on high-resolution images in order to classify the territory in basic and generic land uses. This procedure will be used to control the sustainable management of plots belonging to the Land Bank. This paper presents an application study for maintaining and updating land use/land cover geospatial databases using parcel-oriented classification. The test is performed over two geographic areas of Galicia, in the northwest of Spain. In this region, forest and shrublands in mountain environments are very heterogeneous with many private unproductive plots, some of which are in a high state of abandonment. The dataset is made of high spatial resolution multispectral imagery, cadastral cartography employed to define the image objects (plots), and field samples used to define evaluation and training samples. A set of descriptive features is computed quantifying different properties of the objects, i.e. spectral, texture, structural, and geometrical. Additionally, the effect on the classification and updating processes of the historical land use as a descriptive feature is tested. Three different classification methodologies are analyzed: linear discriminant analysis, decision trees, and support vector machine. The overall accuracies of the classifications obtained are always above 90 % and support vector machine method is proved to provide the best performance. Forest and shrublands areas are especially undefined, so the discrimination between these two classes is low. The results enable to conclude that the use of automatic parcel-oriented classification techniques for updating tasks of land use/land cover geospatial databases, is effective in the areas tested, particularly when broad and well defined classes are required.The authors appreciate the collaboration and support provided by Xunta de Galicia, Sociedade para o Desenvolvemento Comarcal de Galícia, and Banco de Terras de Galicia. The financial support provided by the Spanish Ministerio de Ciencia e Innovación in the framework of the projects CGL2010-19591/BTE and CGL2009-14220 is also acknowledged.Hermosilla, T.; Díaz Manso, J.; Ruiz Fernández, LÁ.; Recio Recio, JA.; Fernández-Sarría, A.; Ferradáns Nogueira, P. (2012). Analysis of parcel-based image classification methods for monitoring the activities of the Land Bank of Galicia (Spain). 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    The Study of Quantum Interference in Metallic Photonic Crystals Doped with Four-Level Quantum Dots

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    In this work, the absorption coefficient of a metallic photonic crystal doped with nanoparticles has been obtained using numerical simulation techniques. The effects of quantum interference and the concentration of doped particles on the absorption coefficient of the system have been investigated. The nanoparticles have been considered as semiconductor quantum dots which behave as a four-level quantum system and are driven by a single coherent laser field. The results show that changing the position of the photonic band gap about the resonant energy of the two lower levels directly affects the decay rate, and the system can be switched between transparent and opaque states if the probe laser field is tuned to the resonance frequency. These results provide an application for metallic nanostructures in the fabrication of new optical switches and photonic devices

    Diagnosing Schistosomiasis by Detection of Cell-Free Parasite DNA in Human Plasma

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    Bilharzia (schistosomiasis) occurs in the tropics and subtropics and is one of the most important parasite diseases of humans. It is caused by flukes residing in the vessels of the gut or bladder, causing fever, pain, and bleeding. Bladder cancer or esophageal varices may follow. Diagnosis is difficult, requiring detection of parasite eggs in stool, urine, or gut/bladder biopsies. In this paper, we introduce a fundamentally new way of diagnosing bilharzia from the blood. It has been known for almost 20 years that patients with cancer have tumor-derived DNA circulating in their blood, which can be used for diagnostic purposes. During pregnancy, free DNA from the fetus can be detected in motherly blood, which can be used for diagnosing a range of fetal diseases and pregnancy-associated complications. We found that parasite DNA can be detected in the same way in the blood of patients with bilharzia. In patients with early disease, diagnosis was possible earlier than with any other test. DNA could be detected in all patients with active disease in our study. Patients after treatment had significantly lower parasite DNA concentrations and turned negative 1–2 years after treatment. Future studies should implement the method in large cohorts of patients and should define criteria for the confirmation of the success of treatment by comparing the concentration of fluke DNA before and after therapy

    Posters display III clinical outcome and PET

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