59 research outputs found
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New electroactive macromonomers and multi-responsive PEDOT graft copolymers
Poly(3,4-ethylenedioxithiophene) (PEDOT) is the conducting polymer with the biggest prospects in the field of organic electronics due to its high electrical conductivity and transparency as thin films.Marie Curie IF BIKE Project No. 74286
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Role of Microbes as Biocolloids in the Transport of Actinides from a Deep Underground Radioactive Waste Repository
We investigated the interaction of dissolved actinides Th, U, Np Zgpu, and Am, with a pure and a mixed culture of halophilic bactezia isolated from the Waste Isolation H.Iot Plant repository under anaerobic conditions to evaluate their potentiaI transport as biocolloids from the waste site. The sizes of the bacterial cells studied ranged from ().54 x 0.48 pm to 7.7 x 0.67pm Using sequential mimofiltration, we determined the ~~ation of actinides with fi-ee-living (mobile) bacterial cells suspended in a fluid medium containing. NaCl or M=W12 brine, at various phaes of their growth cycIes. The number of suspended kcteria rangy-d born 106 to 109 cells ml-*. Tine amount of actinide associatd with the wspend~ cell fraction (cakzdated & mol cell-*) was very Iow: Th, 10-*2; U, 10-1s - 10-lS; - ~ Np, 1o-15- 10-19; Pu, 10-ls -10-21 ; and h, 10-1* - 10-*9 ; and it varied with the bacteihl - CUIture studied. l%e differe&es in the asswiation are amibuted to the extent of bioamxmdation and biosorption by the bacteria pH, the compo&on of the brine, and the speziation and bioavaiIability of the actinides
Tyrosine and tyramine increase endogenous ganglionic morphine and dopamine levels in vitro and in vivo: cyp2d6 and tyrosine hydroxylase modulation demonstrates a dopamine coupling
Background: The ability of animals to make morphine has been in question for the last 30 years. Studies have demonstrated that animals do contain morphine precursors and metabolites, as well as the ability to use some morphine precursors to make morphine. Material/Methods: The present study uses excised ganglia from the marine invertebrate Mytilus edulis as well as whole animals. Morphine and dopamine levels were determined by high performance liquid chromatography coupled to electrochemical detection and radioimmunoassay. Tissues and whole animals were also exposed to morphine precursors and exposed to the CYP2D6 inhibitor quinidine and the tyrosine hydroxylase inhibitor alpha-methyl-para-tyrosine (AMPT). Additionally, via RT-PCR, a cDNA fragment of the CYP2D6 enzyme in the ganglia of M. edulis was identified. Results: Pedal ganglia incubated with either tyramine or tyrosine, or whole animals receiving injections, exhibited a statistically significant concentration- and time-dependent increase in their endogenous morphine and dopamine levels (2.51 +/- 0.76 ng/g for tyrosine and 2.39 +/- 0.64 ng/g for tyramine compared to approximately 1.0 ng/g morphine wet weight). Incubation with quinidine and/or AMPT diminished ganglionic morphine and dopamine synthesis at various steps in the synthesis process. We also demonstrated that CYP2D6 mediates the tyramine to dopamine step in this process, as did tyrosine hydroxylase in the step from tyrosine to L-DOPA. Furthermore, via RT-PCR, we identified a cDNA fragment of the CYP2D6 enzyme in the ganglia, which exhibits 94% sequence identity with its human counterpart. Evidence that tyrosine and tyramine were, in part, being converted to dopamine then morphine, and that this process can be inhibited by altering either or both CYP2D6 or tyrosine hydroxylase, is also provided. Conclusions: It appears that animals have the ability to make morphine. This process also appears to be dynamic in that the inhibition of one pathway allows the other to continue with morphine synthesis. Moreover, dopamine and morphine synthesis were coupled
Radiation protection of workers associated with secondary neutrons produced by medical linear accelerators
This paper presents a measurement campaign carried out in six medical electron linear accelerator facilities to evaluate occupational exposure associated with photons and secondary neutrons for several encountered configurations. No strong correlation between dose and configuration has been observed. Assuming realistic hypotheses, the annual effective dose to staff due to external exposure has been estimated to 0.9 mSv, 54% associated with the decay of activation products and 7% due to exposure to leakage neutrons. © 2008 Elsevier Ltd. All rights reserved
Interface engineering for high performance, triple halide perovskite silicon tandem solar cells
Improved stability and efficiency of two terminal monolithic perovskite silicon tandem solar cells will require reductions in recombination losses. By combining a triple halide perovskite 1.68 electron volt bandgap with a piperazinium iodide interfacial modification, we improved the band alignment, reduced nonradiative recombination losses, and enhanced charge extraction at the electron selective contact. Solar cells showed open circuit voltages of up to 1.28 volts in p i n single junctions and 2.00 volts in perovskite silicon tandem solar cells. The tandem cells achieve certified power conversion efficiencies of up to 32.
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