Sökresultat

Filtyp

Din sökning på "*" gav 533928 sökträffar

X-ray nanodiffraction on a single SiGe quantum dot inside a functioning field-effect transistor

For advanced electronic, optoelectronic, or mechanical nanoscale devices a detailed understanding of their structural properties and in particular the strain state within their active region is of utmost importance. We demonstrate that X-ray nanodiffraction represents an excellent tool to investigate the internal structure of such devices in a nondestructive way by using a focused synchotron X-ray

Three-dimensional diffraction mapping by tuning the X-ray energy

Three-dimensional reciprocal-space maps of a single SiGe island around the Si(004) Bragg peak are recorded using an energy-tuning technique with a microfocused X-ray beam with compound refractive lenses as focusing optics. The map is in agreement with simulated data as well as with a map recorded by an ordinary rocking-curve scan. The energy-tuning approach circumvents both the comparatively large

Imaging the displacement field within epitaxial nanostructures by coherent diffraction : A feasibility study

We investigate the feasibility of applying coherent diffraction imaging to highly strained epitaxial nanocrystals using finite-element simulations of SiGe islands as input in standard phase retrieval algorithms. We discuss the specific problems arising from both epitaxial and highly strained systems and we propose different methods to overcome these difficulties. Finally, we describe a coherent mi

Three-dimensional X-ray fourier transform holography : The Bragg case

A novel approach to determine the structure of nanoscale crystals in three dimensions is proposed by the use of coherent x-ray Fourier transform holography in Bragg geometry. The full internal description is directly obtained by a single Fourier transform of the 3D intensity hologram. Together with the morphology, Bragg geometry gives access to the 3D displacement field within the crystal. This re

Excessive White Matter Hyperintensity Increases Susceptibility to Poor Functional Outcomes After Acute Ischemic Stroke

Objective: To personalize the prognostication of post-stroke outcome using MRI-detected cerebrovascular pathology, we sought to investigate the association between the excessive white matter hyperintensity (WMH) burden unaccounted for by the traditional stroke risk profile of individual patients and their long-term functional outcomes after a stroke. Methods: We included 890 patients who survived

Ion-induced nanopatterns on semiconductor surfaces investigated by grazing incidence x-ray scattering techniques

In this review we cover and describe the application of grazing incidence x-ray scattering techniques to study and characterize nanopattern formation on semiconductor surfaces by ion beam erosion under various conditions. It is demonstrated that x-rays under grazing incidence are especially well suited to characterize (sub)surface structures on the nanoscale with high spatial and statistical accur

Order parameter segregation in Ce0.7La0.3B6 : 4f octopole and 5d dipole magnetic order

The intriguing thermophysical properties of CeB6 have been subject to investigation for more than 20 years. In particular, an exotic ground state, phase IV, emerges under doping with La. We report resonant x-ray scattering results on the order parameter symmetries in phase IV of Ce0.7La0.3B6, which condenses below TIV=1.5K. The results reveal a degree of mesoscopic 5d dipole antiferromagnetic orde

Biaxial strain and orbital order in la2/3Ca 1/3MnO3 thin films

Biaxially strain is an important parameter in the complex phase diagram of the doped manganites that can lead to a different groundstate compared to bulk single crystals at the same doping level. For coherently strained La 2/3Ca1/3MnO3 thin films on SrTiO3 substrates, we report an unusual direction dependence of the electrical transport properties. For transport perpendicular to the substrate indu

Transport anisotropy in biaxially strained La2/3Ca1/3MnO3 thin films

Due to the complex interplay of magnetic, structural, electronic, and orbital degrees of freedom, biaxial strain is known to play an essential role in the doped manganites. For coherently strained La2/3Ca1/3MnO3 thin films grown on SrTiO3 substrates, we measured the magnetotransport properties both parallel and perpendicular to the substrate and found an anomaly of the electrical transport propert

Efficient high area OFETs by solution based processing of a π-electron rich donor

We report on the preparation of high performance field-effect transistors (FETs) based on large areas of aligned films of a TTF derivative, namely, tetrakis-(octadecylthio)-tetrathiafulvalene (TTF-4SC18). TTF-4SC18 assembles into one-dimensional stacks in which the long alkyl chains promote intermolecular π-π overlapping due to their extremely closely packed nature. The films were prepared from so

Spin and orbital magnetic moments in carbon-encapsulated Fe50 Pt50 nanoparticles

X-ray absorption and magnetic circular dichroism spectra of as-deposited and postannealed Fe50 Pt50 /C granular multilayers were measured at both the Fe and Pt L2,3 edges. We demonstrate that the partial L 10 ordering of the FePt nanoparticles induced by thermal annealing results in an increase of the effective spin magnetic moments by 200% at the Fe site and by 65% at the Pt site, while the orbit

Understanding prediction systems for HLA-binding peptides and T-cell epitope identification

Peptide binding to HLA molecules is a critical step in induction and regulation of T-cell mediated immune responses. Because of combinatorial complexity of immune responses, systematic studies require combination of computational methods and experimentation. Most of available computational predictions are based on discriminating binders from non-binders based on use of suitable prediction threshol

Suppression of HIV replication in vitro by CpG and CpG conjugated to the non toxic B subunit of cholera toxin

Administration of oligodeoxynucleotides (ODNs) containing CpG motifs generates a rapid and potent response of CC-chemokines, known as ligands of the HIV-1 co-receptor CCR5, in the murine female genital tract. The present study explored the potential HIV inhibitory activities of different human CpG prototypes either alone or conjugated to the non-toxic subunit of cholera toxin (CTB). Results showed

t(3;21)(q26;q22) with AML1 rearrangement in a de novo childhood acute monoblastic leukaemia

t(3;21)(q26;q22) is a recurrent chromosomal abnormality in Philadelphia-positive chronic myeloid leukaemia in blast crisis and in treatment-related myelodysplastic syndrome and acute myeloid leukaemia. The molecular consequences of the t(3;21) are presently being unravelled; various transcripts between the AML1 gene in 21q22 and several unrelated genes, i.e. EAP, EVI1 and MDS1, in 3q26 are generat

The plasminogen activator/plasmin system is essential for development of the joint inflammatory phase of collagen type II-induced arthritis

The plasminogen activator (PA) system has been proposed to have important roles in rheumatoid arthritis. Here we have used the autoinumme collagen type II (CII)-induced arthritis (CIA) model and mice deficient for urokinase-type PA (uPA) or plasminogen to investigate the role of the PA system for development of arthritis. Our data revealed that uPA-deficient mice have a lower severity and incidenc

Effect of propofol on isolated human omental arteries and veins

To elucidate the effect and mode of action of propofol on human vascular smooth muscle tension, we have investigated the effect of propofol alone and the effect of propofol on contractions induced by U46619, KCl and caffeine on isolated human omental vessels. Propofol 10(-3) mol litre-1 induced contractions in both arteries and veins attenuated the contraction elicited by U46619, KCl and caffeine

Glucagon secretion in relation to insulin sensitivity in healthy subjects.

Aims/hypothesis: The study evaluated whether glucagon secretion is regulated by changes in insulin sensitivity under normal conditions. Materials and methods: A total of 155 healthy women with NGT (aged 53-70 years) underwent a glucose-dependent arginine-stimulation test for evaluation of glucagon secretion. Arginine (5 g) was injected i.v. under fasting conditions (plasma glucose 4.8 +/- 0.1 mmol