696 research outputs found

    Interaction of Cd(II) and Ni(II) terpyridine complexes with model polynucleotides: a multidisciplinary approach

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    Two metal complexes of 2,2′:6′,2″-terpyridine (terpy), i.e. Cd(terpy)Cl2 and Ni(terpy)Cl2·3H2O, have been prepared and extensively characterized. The interaction of Cd(terpy)Cl2 with synthetic DNA models, poly(dA-dT)·poly(dA-dT) (polyAT) and poly(dG-dC)·poly(dG-dC) (polyGC), has been studied by CD, fluorescence and UV-vis electronic absorption spectroscopy at several metal/polynucleotide-phosphate ratios and for different NaCl concentrations. All the experimental results indicate an intercalative mechanism of interaction. The optimized geometry of the cadmium complex intercalated between the sixth and seventh base pairs of (AT) and (GC) dodecanucleotide duplexes, obtained by quantum mechanics/molecular mechanics (QM/MM) calculations, lends support to the proposed mechanism. The calculated models provide some additional structural details of the intercalation complex at the molecular level. To evidence the influence of the charge and geometry of the metal complex on the mechanism of interaction with polynucleotides, the nickel complex-polyAT system has been studied to some extent by means of CD and UV-vis spectroscopy, and by thermal melting experiments. The results suggest that the octahedral complex cation [Ni(terpy)(H2O)2Cl]+ interacts with polyAT by partial intercalation assisted by electrostatic interaction with the negative charges of the backbone phosphate groups

    Autonomous Observations in Antarctica with AMICA

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    The Antarctic Multiband Infrared Camera (AMICA) is a double channel camera operating in the 2-28 micron infrared domain (KLMNQ bands) that will allow to characterize and exploit the exceptional advantages for Astronomy, expected from Dome C in Antarctica. The development of the camera control system is at its final stage. After the investigation of appropriate solutions against the critical environment, a reliable instrumentation has been developed. It is currently being integrated and tested to ensure the correct execution of automatic operations. Once it will be mounted on the International Robotic Antarctic Infrared Telescope (IRAIT), AMICA and its equipment will contribute to the accomplishment of a fully autonomous observatory.Comment: 12 pages, 4 figures, Advances in Astronomy Journal, Special Issue "Robotic Astronomy", Accepted 11 February 201

    Featured Facsimile: Mauro Giuliani’s \u3ci\u3eZwölf neue Wald-Ländler\u3c/i\u3e (Twelve New Forest-Ländler), Op. 23

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    Giuliani\u27s Zwölf neue Wald-Ländler (Twelve New Forest-Ländler), Op. 23, in score. It was first published by the prestigious firm of Artaria & Co., with plate no. 2710, advertised for sale on 27 January 1810. Characteristic of these waltzes were the chordal (triadic) melodies, inspired stylistically by yodelers and yodeling. The intervallic tuning of the guitar favors the performance of such melodies as these, which evoke a style of folk music that runs deep in Austrian musical consciousness. Usually performed in sets of twelve, all in the same key, a Ländler-reihe (set, or row) usually began slowly, accelerated gradually toward the middle of the set, and slowed down again towards the end

    Metals in Sediment Cores from Nine Coastal Lagoons in Central Vietnam

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    Problem statement: After being dramatically hit by war events, Vietnam is presently experiencing a huge economical and social development. However, very few data, relative to pollution levels and trends, are available for the correct management of critical areas such as coastal lagoons, where many economical activities are linked to high value environmental features. Approach: A set of sediment cores from nine coastal lagoons of central Vietnam (Lang Co, Truong Giang, An Khe, Nuoc Man, Nuoc Ngot, Thi Nai, O Loan, Thuy Trieu and Dam Nai) were sampled in 2008 and analyzed to assess metal and (Al, Cd, Cr, Cu, Fe, Hg, Li, Mn, Ni, Pb, V, U and Zn) and As levels and historical trends. Results: Concentrations are generally low, with the exception of As, which often exceeds ERL guidelines and Ni that does the same at O Loan. In some cases, concentrations-depth profiles account for recent increasing trends but surficial values are still low when compared to both international guidelines and polluted sediments all around the world. Sediment grain size seems to affect the depth distribution of a number of metals and when normalized to the content of silt and clay, values are particularly high at Dam Nai and Thi Nai, due to the very coarse composition of surficial sediments. Conclusion: Metal concentrations in lagoon sediments derive from the composition of rocks and soils in the watersheds. However, recent increasing trends need for further monitoring

    Deal2lkit: a Toolkit Library for High Performance Programming in deal.II

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    We propose a software design for the efficient and flexible handling of the building blocks used in high performance finite element simulations, through the pervasive use of parameters (parsed through parameter files). In the proposed design, all the building blocks of a high performance finite element program are built according to the command and composite design patterns.We present version 1.1.0 of the deal2lkit (deal.II ToolKit) library, which is a collection of modules and classes aimed at providing high level interfaces to several deal.II classes and functions, obeying the command and composite design patterns, and controlled via parameter files. Keywords: Object-orientation, Software design, Finite element methods, C+

    Clastogenicity and aneuploidy in newborn and adult mice exposed to 50 Hz magnetic fields.

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    Purpose:?To detect possible clastogenic and aneugenic properties of a 50 Hz, 650 ?T magnetic field. Materials and methods:?The micronucleus test with CREST (Calcinosis, Raynaud's phenomenon, Esophageal dismotility, Sclerodactility, Telangectasia) antibody staining was performed on liver and peripheral blood sampled from newborn mice exposed to an ELF (Extremely Low Frequency) magnetic field during the whole intra-uterine life (21 days), and on bone marrow and peripheral blood sampled from adult mice exposed to the same magnetic field for the same period. Results:?Data obtained in newborn mice show a significant increase in micronuclei frequencies. In absolute terms, most of the induced micronuclei were CREST-negative (i.e., formed by a chromosome fragment). However, in relative terms, ELF exposure caused a two-fold increase in CREST-negative micronuclei and a four-fold increase in CREST-positive micronuclei (i.e., formed by a whole chromosome). No significant effect was recorded on exposed adults. Conclusions:?These findings suggest the need for investigation of aneugenic properties of ELF magnetic fields in order to establish a possible relationship to carcinogenesis

    Anthracyclines gels: Chemical structure and functional behaviour

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    Anthracyclines are a family of antibiotics often used in cancer chemotherapy. Daunorubicin (DA) was the first isolated from a strain of Streptomyces peucetius back in 1960 and still in use for the treatment of several malignancies together with the even more frequently used analogue Doxorubicin (DX, also called Adriamycin) and its semisynthetic derivative Epirubicyn (EPI). Despite their extremely close chemical formula (Figure 1), their properties when in solution are enormously different. In fact, whereas the increase of the ionic strength induces the formation of a gel with DX1-3, in the case of the related EPI and DA molecules what is observed are only the well-known self-association phenomena documented in the literature from decades4. Please click Additional Files below to see the full abstract
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