990 resultados para injection vs rapid,


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Serious concerns have been raised about the ecological effects of industrialized fishing1, 2, 3, spurring a United Nations resolution on restoring fisheries and marine ecosystems to healthy levels4. However, a prerequisite for restoration is a general understanding of the composition and abundance of unexploited fish communities, relative to contemporary ones. We constructed trajectories of community biomass and composition of large predatory fishes in four continental shelf and nine oceanic systems, using all available data from the beginning of exploitation. Industrialized fisheries typically reduced community biomass by 80% within 15 years of exploitation. Compensatory increases in fast-growing species were observed, but often reversed within a decade. Using a meta-analytic approach, we estimate that large predatory fish biomass today is only about 10% of pre-industrial levels. We conclude that declines of large predators in coastal regions5 have extended throughout the global ocean, with potentially serious consequences for ecosystems5, 6, 7. Our analysis suggests that management based on recent data alone may be misleading, and provides minimum estimates for unexploited communities, which could serve as the ‘missing baseline’8 needed for future restoration efforts.

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With the target to design and develop new functionalized green triplet light emitters that possess distinctive electronic properties for robust and highly efficient phosphorescent organic light-emitting diodes (PHOLEDs), a series of bluish-green to yellow-green phosphorescent tris-cyclometalated homoleptic iridium(III) complexes [Ir(ppy-X)(3)] (X=SiPh3, GePh3, NPh2, POPh2, OPh, SPh, SO2Ph, Hppy=2-phenylpyridine) have been synthesized and fully characterized by spectroscopic, redox, and photophysical methods

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Polyethylenimine (PEI)-protected Prussian blue nanocubes have been simply synthesized by heating an acidic mixture of PEI, FeCl3, K3Fe(CN)(6), and KCI. The experiment results presented here demonstrate that the pH of the mixture plays an important role in controlling the shape and composition of the resultant product.

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We have reported a facile and general method for the rapid synthesis of hollow nanostructures with urchinlike morphology. In-situ produced Ag nanoparticles can be used as sacrificial templates to rapidly synthesize diverse hollow urchinlike metallic or bimetallic (such as Au/Pt) nanostructures. It has been found that heating the solution at 100 degrees C during the galvanic replacement is very necessary for obtaining urchinlike nanostructures. Through changing the molar ratios of Ag to Pt, the wall thickness of hollow nanospheres can be easily controlled; through changing the diameter of Ag nanoparticles, the size of cavity of hollow nanospheres can be facilely controlled; through changing the morphologies of Ag nanostructures from nanoparticle to nanowire, hollow Pt nanotubes can be easily designed. This one-pot approach can be extended to synthesize other hollow nanospheres such as Pd, Pd/Pt, Au/Pd, and Au/Pt. The features of this technique are that it is facile, quick, economical, and versatile.

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In this paper, we described a simple and rapid method, capillary electrophoresis with electrochemiluminescence (CE-ECL) detection using tris(2,2'-bipyridyl)ruthenium(II) (Ru(bpy)(3)(2+)), to simultaneously detect pethidine and methadone. Analytes were injected to separation capillary of 67.5 cm length (25 mu m i.d., 360 mu m o.d.) by electrokinetic injection for 10 s at 10 kV.

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The effect of the initial states (disordered perpendicular cylinder structure vs. parallel cylinder structure) on the crystallization of polystyrene-block-poly(ethylene oxide) (PS-b-PEO) thin films during cyclohexane annealing was investigated. The cylindrical domains perpendicular or parallel to the surface were obtained by controlling the film thickness. During solvent annealing, for the film with the perpendicular cylinders, the ordering degree of cylinders was increased.

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A soluble nonionic surfactant, polyethylenimine 80% ethoxylated (PEIE) solution, was used as the electron injection material in inverted bottom-emission organic light emitting diodes (OLEDs). The transparent PEIE film was formed on indium-tin-oxide cathode by simple spin-coating method and it was found that the electron injection was greatly enhanced. The devices with PEIE electron injection layer had achieved significant enhancement in luminance and efficiency. The maximum luminance reached 47 000 cd/m(2), and the maximum luminance efficiency and power efficiency arrived at 19.7 cd/A and 10.6 lm/W, respectively.

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We demonstrate highly efficient inverted bottom-emission organic light-emitting diodes (IBOLEDs) by using cesium hydroxide (CsOH) doped tris-(8-hydroxyquinoline) aluminum (Alq(3)) as the electron injection layer on indium tin oxide cathode, which could significantly enhance the electron injection, resulting in a large increase in luminance and efficiency. The maximum luminance, current efficiency, and power efficiency reach 21 000 cd/cm(2), 6.5 cd/A, and 3.5 lm/W, respectively, which are 40%-50% higher in efficiency than that of IBOLEDs with cesium carbonate (Cs2CO3) doped Alq(3) as the electron injection layer, where the efficiencies are only 4.5 cd/A and 2.2 lm/W.

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Amyloid beta peptide plays a critical role in the pathogenesis of Alzheimer's disease (AD). Metal ions are highly enriched in cerebral amyloid deposits in AD and are proposed to be able to mediate A beta conformation. Therefore, a rapid, low-cost, and sensitive detection of metal-induced A beta aggregation and their relation to AD is clearly needed for the clinical diagnosis and treatment. In this report, we study metal-induced A beta aggregation by a rapid, label-free electrochemical method and monitor both the aggregation kinetics and the morphology in the absence or presence of Zn (II) and Cu (II).

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Quantum-chemistry methods were explored to investigate the electronic structures, injection and transport properties, absorption and phosphorescence mechanism of a series of blue-emitting Ir(III) complexes {[(F-2-ppy)(2)Ir(pta -X/pyN4)], where F-2-ppy = (2,4-difluoro)phenylpyridine; pta = pyridine-1,2,4-triazole; X = phenyl(1); p-tolyl (2); 2,6-difluororophenyl (3); -CF3 (4), and pyN4 = pyridine-1,2,4-tetrazolate (5)}, which are used as emitters in organic light-emitting diodes (OLEDs). The mobility of hole and electron were studied computationally based on the Marcus theory. Calculations of Ionization potentials (IPs) and electron affinities (EAs) were used to evaluate the injection abilities of holes and electrons into these complexes.

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In this work, rapid fabrication of Au nanoparticle (Au NP) films has been simply achieved by alternate adsorption of citrate-stabilized Au NPs and poly(diallyldimethylammonium chloride) with the aid of centrifugal force. In contrast to conventional electrostatic assembly, we carried out the assembly process in a centrifuge with a rotating speed of 4000 rpm, where centrifugal force can be imposed on Au NPs. Scanning electron microscopy and cyclic voltammetry were employed to characterize the assembly procedure and the thus-prepared thin solid films. Our results demonstrate that centrifugal force can promote the assembly of Au NPs and therefore enable the rapid fabrication of functional Au NP films.

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Efficient inverted top-emitting organic light-emitting diodes with aluminum (Al) as both the cathode and semitransparent anode are investigated. It is found that introduction of the ultrathin molybdenum trioxide (MoO3)/fullerene (C-60) bilayer structure between the low work function Al top anode and the hole-transporting layer dramatically enhances the device performance as compared to the devices with sole MoO3 or C-60 buffer layer. The ultraviolet photoemission spectroscopy and x-ray photoelectron spectroscopy indicate that the hole injection barrier between Al anode and hole-transporting layer is effectively reduced via strong dipole effect at Al/MoO3/C-60 interfaces with its direction pointing from Al to C-60.

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By introducing an effective electron injection layer (EIL) material, i.e., lead monoxide (PbO), combined with the optical design in device structure, a high efficiency inverted top-emitting organic light-emitting diode (ITOLED) with saturated and quite stable colors for different viewing angles is demonstrated. The green ITOLED based on 10-(2-benzothiazolyl)-1, 1, 7, 7-tetramethyl-2, 3, 6, 7-tetrahydro-1H, 5H, 11H-[1] benzopyrano [6, 7, 8-ij] quinolizin-11-one exhibits a maximum current efficiency of 33.8 cd/A and a maximum power efficiency of 16.6 lm/W, accompanied by a nearly Lambertian distribution as well as hardly detectable color variation in the 140 forward viewing cone. A detailed analysis on the role mechanism of PbO in electron injection demonstrates that the insertion of the PbO EIL significantly reduces operational voltage, thus greatly improving the device efficiency.