We have demonstrated an organic light-emitting diode based on molybdenum oxide ͑MoO x ͒ doped 4,4Ј ,4Љ-tris͑3-methylphenylphenylamino͒triphenylamine ͑m-MTDATA͒ as a p-type doping hole injection layer. The tris-͑8-hydroxyquinoline͒ aluminum ͑Alq 3 ͒-based organic light-emitting diodes show high brightness at very low operating voltage, 100 cd/ m 2 at 3.2 V and 1000 cd/ m 2 at 4.4 V, corresponding to a low turn-on voltage of 2.4 V. Such improved properties are attributed to the formation of the charge transfer complex produced by doping MoO x into m-MTDATA, which provides much more free hole carriers, and the introduction of an efficient electron-injecting layer to improve the performance.
Complementary to endocytosis, cell-penetrating
peptides (CPPs)
at high concentrations can penetrate the cell membrane in a direct
way, which further makes CPPs popular candidates for delivering therapeutic
or diagnostic agents. Although featured as rapid uptake, the translocation
efficiency and potential toxicity of the direct penetration are usually
affected by cargoes, which is still unclear. Here, using coarse-grained
molecular dynamics simulations, we show that the polyarginine (R8) peptides penetrate the membrane through a water pore in
the membrane, and the transmembrane efficiency is improved by conjugating
to small nanoparticles (NPs) with proper linkers. It can be attributed
to both the extension of the lifetime of the water pore by the NPs
and outward diffusion of negative lipids in the asymmetry membrane,
which induces the surrounding R8–NP conjugates to
the water pore before it is closed. The translocation efficiency is
closely related to the length of the linkers, and it gets the maximum
value when the length of the linkers is around half of the membrane
thickness. Overlong linkers not only decrease the transmembrane efficiency
because of the blockage of NPs in the water pore but may also cause
cytotoxicity because of the unclosed water pore. The results provide
insights into the internalization of CPPs and facilitate the design
of CPP and drug conjugates with high efficiency and low toxicity.
Articles you may be interested inControl of magnetoconductance through modifying the amount of dissociated excited states in tris-(8hydroxyquinoline) aluminum-based organic light-emitting diodes Appl. Phys. Lett. 96, 203303 (2010); 10.1063/1.3430044 Highly efficient tris(8-hydroxyquinoline) aluminum-based organic light-emitting diodes utilized by balanced energy transfer with cosensitizing fluorescent dyes
Within a hydro-inspired blast-wave model, we combine the single-particle m t spectra of π − and transverse mass dependence of two-pion HBT radius R s to extract the thermal freeze-out temperature T and the surface radial flow rapidity ρ 0 for six centrality classes in Au+Au collisions at √ s NN = 200 GeV measured by the STAR Collaboration at the RHIC. The obtained T and ρ 0 are consistent with those of simultaneous fits of the single-particle m t spectra of π ± , K ± , p and p except for the peripheral collisions. The data can be well described by the blast-wave model, and the assumption that π ± , K ± , p and p freeze-out with the same thermal temperature and transverse flow profile is relatively good for central and mid-central collisions. Furthermore, we simulate the blast-wave emitting source by a Monte Carlo method and use the program CRAB to get the transverse mass dependence of the kaon HBT radius R s . The 1σ chi-square contours of m t spectrum and HBT radius R s of kaon have a relatively wide overlap region in the T-ρ 0 plane, which leads to large errors when we combine both observables of kaon to extract its temperature and flow velocity.
We describe the transverse momentum spectra or transverse mass spectra of
π
±
,
K
±
,
p
, and
p
¯
produced in central gold-gold (Au-Au), central lead-lead (Pb-Pb), and inelastic proton-proton (pp) collisions at different collision energies range from the AGS to LHC by using a two-component (in most cases) Erlang distribution in the framework of multisource thermal model. The fitting results are consistent with the experimental data, and the final-state yield ratios of negative to positive particles are obtained based on the normalization constants from the above describing the transverse momentum (or mass) spectra. The energy-dependent chemical potentials of light hadrons (
π
,
K
, and
p
) and quarks (
u
,
d
, and
s
) in central Au-Au, central Pb-Pb, and inelastic (pp) collisions are then extracted from the modified yield ratios in which the contributions of strong decay from high-mass resonance and weak decay from heavy flavor hadrons are removed. The study shows that most types of energy-dependent chemical potentials decrease with increase of collision energy over a range from the AGS to LHC. The curves of all types of energy-dependent chemical potentials, obtained from the fits of yield ratios vs. energy, have the maximum at about 3.510 GeV, which possibly is the critical energy of phase transition from a liquid-like hadron state to a gas-like quark state in the collision system. At the top RHIC and LHC, all types of chemical potentials become small and tend to zero at very high energy, which confirms that the high energy collision system possibly changes completely from the liquid-like hadron-dominant state to the gas-like quark-dominant state and the partonic interactions possibly play a dominant role at the LHC.
Using the AMPT model with string melting, we investigate the effect of collective phase transition of partons on the two-pion HBT radii. The results indicate that collective hadronization of partons at t = 5 fm/c flattens the transverse mass dependence of HBT radii, especially for transverse radii R o and R s . The radii calculated from the pion emission function (exclude pions with freeze-out time after 30 fm/c) are consistent with the HBT radii obtained by Gaussian fit to the correlation function. The r-t correlation and coordinate-momentum correlation of a pion source for collective hadronization are relatively weaker than those for parton-wise hadronization.
Using atomistic empirical pseudopotentials, we have calculated the electronic structures of CdSe nanowires with a bulged area. The localized state wavefunctions and their binding energies are calculated, and their dependences on the bulged area shape are analyzed. We find that both the binding energy and the wavefunction localization strongly depend on the bulged area shape, with the most compact shape produces the largest binding energy and strongest wavefunction localization. We also find that the top of the valence band state has a weaker localization than the bottom of the conduction band state due to an effective mass anisotropy.
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