The morphology of cobalt, palladium, and platinum nanoclusters grown on a gold surface is analyzed from both thermodynamic and kinetic viewpoints. Although the thermodynamic equilibrium shape as a ...function of cluster size is similar for all three elements and shows a morphology transition from monolayer to bilayer, only Co clusters meet their stable state and undergo a transition. Atomistic simulations on a picosecond to nanosecond time scale evidence kinetic limitations for Pt and Pd, and allow us to understand the experimentally observed morphology for the different species. It is shown that stress relaxation, by strongly influencing the energy activation for atom hopping from first to second cluster layer and the magnitude of vibration of the atoms, is the determinant parameter for the existence or absence of the cluster morphology transition.
We have studied the influence of Pt capping on the magnetic properties of self-organized Co nanodots by means of complementary structural and magnetic investigation techniques. The growth of ...monodisperse 5 nm diameter Co dots on a Au(111) surface and its progressive coverage by Pt were performed under ultrahigh vacuum conditions and imaged by scanning tunneling microscopy, revealing a weak mixing at room temperature. The Co/Pt core-shell structure was studied both by molecular-dynamics simulations and surface extended x-ray-absorption fine structure, showing a global dilatation of the Co core. Both magnetic moments and hysteresis cycles at various temperatures were measured using x-ray magnetic circular dichroism, revealing a slight increase of the magnetic moments and the out-of-plane magnetic anisotropy after Pt capping. Moreover, the variation of magnetic anisotropy as a function of capping was followed in situ by the magneto-optical Kerr effect. Our investigations demonstrate that interfacial hybridization between Co and Pt is dominant over magnetoelastic contribution in this system.
Fast adiabatic plasma heating of a thin solid target irradiated by a high intensity laser has been observed by optical fast interferometry diagnostic. It is driven by the hot electron current induced ...by the laser plasma interaction at the front side of the target. Radial and longitudinal temperature profiles are calculated to reproduce the observed rear side plasma expansion. The main parameters of the suprathermal electrons have been calculated from these observations.
METHODS: 15 patients suffering with anaphylaxis, 35 with mild symptoms upon peanut ingestion, and 8 peanut tolerant individuals with positive skin test were studied.
Motivated by recent experiments demonstrating the creation of atomically sharp interfaces between hexagonal sapphire and cubic SrTiO\(_3\) with finite twist, we here develop and study a general ...electronic band theory for this novel class of moiré heterostructures. We take into account the three-dimensional nature of the two crystals, allow for arbitrary combinations of Bravais lattices, finite twist angles, and different locations in momentum space of the low-energy electronic bands of the constituent materials. We analyze the general condition for a well-defined crystalline limit in the interface electron system and classify the associated "crystalline reference points". We discuss this in detail for the example of the two-dimensional lattice planes being square and triangular lattices on the two sides of the interface; this reveals non-trivial reference points at finite twist angle and lattice mismatch, leading to a novel form of magic angles, which we refer to as "geometric magic angles". We further show that band structures of mixed dimensionality naturally emerge, where quasi-one- and two-dimensional pockets coexist. Explicit computations for different bulk Bloch Hamiltonians yield a collection of interesting features, such as isolated bands localized at interfaces of non-topological insulators, Dirac cones, van Hove singularities, a non-trivial evolution of the band structures with Zeeman-field, and topological interface bands. Our work illustrates the potential of these heterostructures and is anticipated to provide the foundation for moiré interface design and for the analysis of correlated physics in these systems.
The electrons produced in the interaction of a high repetition rate laser with a thick tantalum target generate a continuous distribution of photons via the bremsstrahlung process occurring mainly in ...the target. The photon energy distributions, between 50 and 500 keV, are unfolded to obtain the true X-ray energy distributions. These distributions are used in a Monte Carlo simulation to infer the initial electron energy distributions. These properties have been studied at laser intensities ranging from 3 × 10
15
to 6 × 10
16
W cm
− 2
. The electron energy distributions are different above ≃2 × 10
16
W cm
− 2
as compared to lower intensities. This is evidence for a different laser plasma interaction regime.
Abstract
Background
Up to 25% of food allergic subjects in central
E
urope suffer from carrot allergy. Until now, two isoforms of the major carrot (
D
aucus carota
) allergen Dau c 1 have been ...described: Dau c 1.01, comprising five variants (Dau c 1.0101–Dau c 1.0105) and Dau c 1.02.
Objective
To investigate potential allergenic properties of a Dau c
PRP
like protein, a novel isoform of the
PR
‐10 protein family in carrot.
Methods
Dau c
PRP
like
cDNA
from carrot roots (cv
R
odelika
) was cloned after RT‐PCR and 5′RACE. Dau c
PRP
like protein was expressed in
E
. coli
, purified under native conditions by Ni‐NTA chromatography and analysed by
CD
spectroscopy. Immuno‐reactivity of the
rD
au c
PRP
like protein was compared with
rD
au c 1.0104 and
rD
au c 1.0201 in terms of IgE binding (immunoblotting, ImmunoCAP
™
), IgE cross‐reactivity (ELISA inhibition) and
in vitro
mediator release with sera from carrot allergic patients.
mRNA
expression of Dau c
PRP
like protein in wild‐type and transgenic carrot roots was analysed by
qRT
‐
PCR
.
Results
The Dau c
PRP
like protein was identified as a new allergenic isoform, Dau c 1.03, in carrot roots. 68% of carrot allergic patients were sensitized to
rD
au c 1.03. The IgE‐reactivity of
rD
au c 1.03 strongly correlated with reactivity to
rD
au c 1.0104, but not to
rD
au c 1.0201. The extent of IgE cross‐reactivity and allergenic potency of Dau c 1 isoforms varied between the individual sera tested. Dau c 1.03
mRNA
transcripts were up‐regulated in Dau c 1.01 and Dau c 1.02 gene‐silenced carrot roots.
Conclusion and clinical relevance
Dau c 1 isoforms display distinct IgE epitope heterogeneity. Dau c 1.03 appears to contribute to the allergenicity of carrots and the manifestation of carrot allergy. The epitope diversity of different Dau c 1 isoforms should be considered for component‐resolved diagnosis and gene silencing of carrot allergens.
Sensitivity of Plasmodium falciparum populations from Colombia (N = 38) and Tanzania (N = 45) to the newly developed, fully synthetic peroxide OZ277 was investigated using a standard isotopic ...microtest. OZ277 showed excellent activity against chloroquine-resistant isolates in Colombia with median IC(50) range values of 2.5 ng/mL 0.34-8 (4.4 nM 0.6-14) and Tanzania with 1.5 ng/mL 0.22-10 (2.65 nM 0.4-17.7). The potency of OZ277 was similar to artesunate, showing median IC(50) values of 1.5 ng/mL 0.42-8.6 (3.8 nM 1.1-22.3) and 1.8 ng/mL 0.2-10 (4.7 nM 0.5-26.04) in Colombia and Tanzania, respectively. These results support the development of this new antimalarial compound.
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