52 research outputs found

    Tyrian purple : an ancient natural dye for cross-conjugated n-type charge transport

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    Herein, we present two novel organic semiconducting polymers synthesised from an ancient dye. By employing cross-conjugation within the polymer backbone as a synthetic strategy, we are able to engineer optical gaps such that the novel materials absorb over the entire visible spectrum. The cross-conjugated polymers exhibited relatively high n-type charge transport performance in organic field-effect transistors, a rare characteristic for this type of polymer. Quantum chemical calculations provide insight into this behaviour, suggesting that, whilst conjugation along the HOMO is indeed inhibited via molecular design, these materials possess highly delocalized LUMOs, facilitating high n-type charge transport

    Ecology of neotropical mistletoes: an important canopy-dwelling component of Brazilian ecosystems

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    Long-lasting decreases of type II calmodulin kinase expression in kindled rat brains

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    The kindling model of epilepsy is associated with long-lasting changes in type II calmodulin kinase (CaM kinase) activity and immunoreactivity. In order to determine the mechanism of these alterations, we measured gene expression of CaM kinase using in situ hybridization in septally kindled rat brains and paired controls using a 35S-labeled riboprobe for the β subunit of the enzyme. We found CaM kinase mRNA concentrated in the hippocampus and other limbic structures. Kindling decreased hippocampal CaM kinase mRNA by 30% in CA1, 34% in CA2, 35% in CA3 41% in CA4, and 29% in the dentate gyrus. Hybridization was also decreased by 21% in the cerebral cortex but not in the lateral septum. These changes are similar in distribution and direction to those previously measured by immunohistochemistry. These data suggest that altered CaM kinase activity and immunoreactivity associated with kindling reflect long-lasting alterations in gene expression of this important synaptic protein, and provide further evidence for its possible importance in the kindling phenomenon. © 1992.SCOPUS: ar.jinfo:eu-repo/semantics/publishe
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