High-efficiency orange and yellow organic light-emitting devices using platinum(II) complexes containing extended π -conjugated cyclometalated ligands as dopant materials

Two luminescent platinum(II) complexes 1 and 2 containing extended π -conjugated cyclometalated ligands have been used as dopant materials for the construction of two high-efficiency organic light-emitting devices I and II. Device I (containing dopant 1) emits orange emission and exhibits a maximum external quantum efficiency of 12.4%, a maximum luminous efficiency of 32.3 cdA, and a maximum power efficiency of 11.2 lmW. Device II (containing dopant 2) emits yellow light and exhibits a maximum external quantum efficiency of 16.1%, a maximum luminous efficiency of 51.8 cdA, and a maximum power efficiency of 23.2 lmW. © 2007 American Institute of Physics.published_or_final_versio

Oxidative stress and immunologic responses following a dietary exposure to PAHs in Mya arenaria

<p>Abstract</p> <p>Background</p> <p>The aim of this research was to investigate oxidative stress and immune responses following a dietary polycyclic aromatic hydrocarbon (PAH) exposure in a marine bioindicator organism, the soft shell clam, <it>Mya arenaria</it>. Immune parameters in hemolymph (haemocyte number, efficiency of phagocytosis and haemocyte activity) and assessment of oxidative stress using catalase (CAT) activity and levels of malondialdehyde (MDA) performed on the digestive gland were estimated as biomarkers in clams fed in mesocosm with PAH contaminated phytoplankton. MDA levels and CAT activities were also measured <it>in situ </it>in organisms sampled in a control site (Metis Beach, Québec, Canada) as well as organisms sampled in a site receiving domestic effluents (Pointe-au-Père, Québec, Canada), to assess effects of abiotic variables related to seasonal variations and mixed contamination on the selected parameters.</p> <p>Results</p> <p>Results on immune parameters suggest that the PAHs may interfere with the maturation and/or differentiation processes of haemocytes. MDA results showed that lipid peroxidation did not occur following the exposure. The levels of CAT activity corresponded to weak antioxidant activity (no significant differences). Recovery was noted for all the immune endpoints at the end of the experiment.</p> <p>Conclusion</p> <p>Results suggest that immune parameters are early biomarkers that can efficiently detect a physiological change during a short term exposure to low concentrations of PAHs. The <it>in situ </it>survey (in the natural environment) suggested that clams from the Pointe-au-Père site did not show any oxidative stress as well as the clams contaminated in mesocosm, probably due to the low concentrations of PAHs used for this study. MDA levels increased however in organisms from Metis Beach, a response probably related to domestic effluents or parasitism.</p

Validating a language scale for Cantonese Chinese preschool children

Language Sciences and Disorders Free Paper SessionOrganized by Division of Speech Therapy & Division of Audiology, Department of Otorhinolaryngology, Head and Neck Surgery, The Chinese University of Hong Kon

Platinum(II) complexes with π-conjugated, naphthyl-substituted, cyclometalated ligands (RC∧N∧N): Structures and photo- and electroluminescence

The crystal structures and photophysical properties of mononuclear [(RC∧N∧N)PtX](ClO 4) n ((RC∧N∧N) = 3-(6′-(2″-naphthyl)-2′-pyridyl)isoquinolinyl and derivatives; X = Cl, n = 0; X = PPh 3 or PCy 3, n = 1), dinuclear [(RC∧N∧N) 2Pt 2(μ-dppm)]-(ClO 4) 2 (dppm = bis(diphenyphosphi-no)methyl) and trinuclear [(RC∧N∧N) 3Pt 3(μ-dpmp)](ClO 4) 3 (dpmp = bis(diphenylphosphinomethyl)phenylphosphine) complexes are presented. The crystal structures show extensive intra- and/or intermolecular π⋯π interactions; the two (RC∧N∧N) planes of [(RC∧N∧N) 2Pt 2(μ-dppm)]-(ClO 4) 2 (R = Ph, 3,5-tBu 2Ph or 3,5-(CF 3) 2Ph) are in a nearly eclipsed configuration with torsion angles close to 0°. [(RC∧N∧N)PtCl], [(RC∧N∧N) 2Pt 2-(μ-dppm)](ClO 4) 2, and [(RC∧N∧N) 3Pt(μ-dpmp)](ClO 4) 3 are strongly emissive with quantum yields of up to 0.68 in CH 2Cl 2 or MeCN solution at room temperature. The [(RC∧N∧N)PtCl] complexes have a high thermal stability (T d = 470-549°C). High-performance light-emitting devices containing [(RC∧N∧N)PtCl] (R = H or 3,5-tBu 2Ph) as a light-emitting material have been fabricated; they have a maximum luminance of 63 000 cd m -2 and CIE 1931 coordinates at x = 0.36, y = 0.54. © 2007 Wiley-VCH Verlag GmbH & Co. KGaA.link_to_subscribed_fulltex

Biomarker studies on gold lined sea bream (Rhabdosargus sarba) exposed to benzo[a]pyrene

Gold-lined sea bream (Rhabdosargus sarba) were intraperitoneally injected with 35 mg/kg benzo [a] pyrene (in DMSO), with fish administered DMSO as the solvent control. Fish were sacrificed 3 days post injection and their livers dissected for the analysis of adenosine triphosphates (ATPase), glutathione-S-transferase (GST), DNA adducts and ethyoxyresorufin-O-deethylase (EROD). Exposure to B[a]P resulted in reduced ATPase activity, elevated GST activity and DNA adduct level, but no apparent change in EROD activity

Energy flow through marine ecosystems: confronting transfer efficiency

Transfer efficiency is a key parameter describing ecosystem structure and function and is used to estimate fisheries production; however, it is also one of the most uncertain parameters.Questions remain about how habitats, food resources, fishing pressure, spatiotemporal scales, as well as temperature, primary production, and other climate drivers impact transfer efficiency.Direct measurements of transfer efficiency are difficult, but observations of marine population abundances, diets, productivity, stable isotope analysis, and models integrating these constraints can provide transfer efficiency estimates.Recent estimates suggest that transfer efficiency is more variable than previously thought, compounding uncertainties in marine ecosystem predictions and projections.Increased understanding of factors contributing to variation in transfer efficiency will improve projections of fishing and climate change impacts on marine ecosystems

Integrated assessment of water quality of the Costa da Morte (Galicia, NW Spain) by means of mussel chemical, biochemical and physiological parameters

Publicado