1,130 research outputs found

    Evidence of environmental strains on charge injection in silole based organic light emitting diodes

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    Using d. functional theory (DFT) computations, the authors demonstrated a substantial skeletal relaxation when the structure of 2,5-bis-[4-anthracene-9-yl-phenyl]-1,1-dimethyl-3,4-diphenyl-silole (BAS) is optimized in the gas-phase comparing with the mol. structure detd. from monocrystal x-ray diffraction. The origin of such a relaxation is explained by a strong environmental strains induced by the presence of anthracene entities. Also, the estn. of the frontier orbital levels showed that this structural relaxation affects mainly the LUMO that is lowered of 190 meV in the gas phase. To check if these theor. findings would be confirmed for thin films of BAS, the authors turned to UV photoemission spectroscopy and/or inverse photoemission spectroscopy and electrooptical measurements. The study of the c.d. or voltage and luminance or voltage characteristics of an ITO/PEDOT/BAS/Au device clearly demonstrated a very unusual temp.-dependent behavior. Using a thermally assisted tunnel transfer model, this behavior likely originated from the variation of the electronic affinity of the silole deriv. with the temp. The thermal agitation relaxes the mol. strains in thin films as it is shown when passing from the cryst. to the gas phase. The relaxation of the intramol. thus induces an increase of the electronic affinity and, as a consequence, the more efficient electron injection in org. light-emitting diodes

    Benzo[1,2-b:4,5-b′]dithio­phene-4,8-dione

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    The title mol­ecule, C10H4O2S2, is situated on a crystallographic center of inversion. In the crystal, weak hydrogen bonding contributes to the packing of the mol­ecules

    M\"ossbauer, nuclear inelastic scattering and density functional studies on the second metastable state of Na2[Fe(CN)5NO]\cdot2H2O

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    The structure of the light-induced metastable state SII of Na2[Fe(CN)5NO]\cdot2H2O 14 was investigated by transmission M\"ossbauer spectroscopy (TMS) in the temperature range 15 between 85 and 135 K, nuclear inelastic scattering (NIS) at 98 K using synchrotron 16 radiation and density functional theory (DFT) calculations. The DFT and TMS results 17 strongly support the view that the NO group in SII takes a side-on molecular orientation 18 and, further, is dynamically displaced from one eclipsed, via a staggered, to a second 19 eclipsed orientation. The population conditions for generating SII are optimal for 20 measurements by TMS, yet they are modest for accumulating NIS spectra. Optimization 21 of population conditions for NIS measurements is discussed and new NIS experiments on 22 SII are proposed

    Incorporation by coordination and release of the iron chelator drug deferiprone from zinc-based metal–organic frameworks

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    A series of new zinc-based metal–organic framework materials has been prepared in which deferiprone is incorporated as a chelating ligand on infinite or tri-zinc secondary building units following deprotonation. Deferiprone is immediately released from the MOFs on treatments with 1 N hydrochloric acid or buffer, but slow release is observed in ethanoic acid

    COMMENTARY: ETHICAL ISSUES OF CURRENT HEALTH-PROTECTION POLICIES ON LOW-DOSE IONIZING RADIATION

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    The linear no-threshold (LNT) model of ionizing-radiation-induced cancer is based on the assumption that every radiation dose increment constitutes increased cancer risk for humans. The risk is hypothesized to increase linearly as the total dose increases. While this model is the basis for radiation safety regulations, its scientific validity has been questioned and debated for many decades. The recent memorandum of the International Commission on Radiological Protection admits that the LNT-model predictions at low doses are “speculative, unproven, undetectable and ‘phantom’.” Moreover, numerous experimental, ecological, and epidemiological studies show that low doses of sparsely-ionizing or sparsely-ionizing plus highly-ionizing radiation may be beneficial to human health (hormesis/adaptive response). The present LNT-model-based regulations impose excessive costs on the society. For example, the median-cost medical program is 5000 times more cost-efficient in saving lives than controlling radiation emissions. There are also lives lost: e.g., following Fukushima accident, more than 1000 disaster-related yet non-radiogenic premature deaths were officially registered among the population evacuated due to radiation concerns. Additional negative impacts of LNT-model-inspired radiophobia include: refusal of some patients to undergo potentially life-saving medical imaging; discouragement of the study of low-dose radiation therapies; motivation for radiological terrorism and promotion of nuclear proliferation

    Quest for barley canopy architecture genes in the hortillus population and whealbi germplasm collection

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    Barley grains are predominantly used for animal feed and malting, and breeding traditionally focused on increase of grain yield by partitioning biomass from straw to grains. The increasing demand for renewable energy sources makes straw, and specially barley straw characterized by the largest content of carbohydrates among the cereals, a valuable product for its potential conversion into biofuels and other products. The BarPLUS project aims at finding genes, alleles and candidate lines related to barley canopy architecture and photosynthesis, to maximize barley biomass and yield (https://barplus.wordpress.com/). In this framework, our research group focuses on identifying genes and alleles controlling tillering, leaf size and leaf angle traits in barley by exploiting both induced and natural allelic variation. Using a forward genetics approach, we screened the HorTILLUS population (Szurman-Zubrzycka et al., 2018) under both field and controlled conditions, identifying 5 mutants with increased tillering and/or erect leaves. After crossing with four reference cultivars, pools of F2 wild-type and mutant plants were selected to map and identify the underlying genes by exome sequencing (Mascher et al., 2014). In parallel, TILLING of the HorTILLUS population identified four lines carrying mutations in the LBO (Lateral branching oxidoreductase) gene involved in tiller number. In order to explore also natural genetic variation, we are taking advantage of the \u2018WHEALBI\u2019 germplasm collection, which includes 403 exome sequenced diverse accessions (BustosKorts et al., 2019): a field trial on a subset of 240 lines (Fiorenzuola d\u2019Arda, Italy) allowed us to conduct a preliminary genome wide association study based on high-throughput phenotyping for leaf angle (PocketPlant3D smartphone app) and quantitative image-analysis for leaf size. Results will be compared with those from a greenhouse experiment on the same 240 accessions to analyze a wide range of morphological traits and identify associated markers and genomic regions
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