36 research outputs found
Emmer wheat using and growing in the Czech Republic
Emmer wheat [(Triticum dicoccum Schrank (Schuebl)] is after bread, durum and spelt wheat further species of wheat
used for economic purposes. Organic farmers and producers have become more and more interested in marginal crops
such as the tetraploid emmer wheat because of its suitability for organic farming. In spite of its historical role, present distribution of emmer is very limited. The work analyzes the problem of growing possibilities of emmer and its suitability for cultivation in organic farming. In the Czech Republic it is grown only a few farms, but in Austria is more popular now. Possible candidates for the cultivation of emmer has several options about where to obtain a suitable variety. The best option appears to be the choice of legally protected variety Rudico. Another option would be to obtain seed from abroad or multiplication of seed of its own genetic resources. Among important properties of emmer belongs e.g. considerably high resistance to some fungal diseases, which make it advantageous in organic system of growing. Hulled grain requires procedure of peeling. High grain quality, first of all high protein content, predetermines emmer wheat for preparation of healthy dishes in bio quality. The grains are suitable for the production of unyeasted products
because of their specific quality. As the emmer wheat is grown especially in the organic farming system, the processing of grains has to respect the individuality of this obsolete cereal species. It may be used for the production of healthy regional food products
Proximity Induced Superconductivity in CdTe-HgTe Core-Shell Nanowires
In this letter we report on proximity superconductivity induced in CdTe-HgTe
core-shell nanowires, a quasi-one-dimensional heterostructure of the
topological insulator HgTe. We demonstrate a Josephson supercurrent in our
nanowires contacted with superconducting Al leads. The observation of a sizable
product, a positive excess current and multiple Andreev reflections
up to fourth order further indicate a high interface quality of the junctions.Comment: Accepted for publication in Nano Letter
Josephson Effect and Charge Distribution in Thin BiTe Topological Insulators
Thin layers of topological insulator materials are quasi-two-dimensional
systems featuring a complex interplay between quantum confinement and
topological band structure. To understand the role of the spatial distribution
of carriers in electrical transport, we study the Josephson effect,
magnetotransport, and weak anti-localization in bottom-gated thin BiTe
topological insulator films.We compare the experimental carrier densities to a
model based on the solutions of the self-consistent Schr\"odinger-Poisson
equations and find excellent agreement. The modeling allows for a quantitative
interpretation of the weak antilocalization correction to the conduction and of
the critical current of Josephson junctions with weak links made from such
films without any ad hoc assumptions.Comment: 18 pages, 6 figure
Conduction spectroscopy of a proximity induced superconducting topological insulator
The combination of superconductivity and the helical spin-momentum locking at
the surface state of a topological insulator (TI) has been predicted to give
rise to p-wave superconductivity and Majorana bound states. The
superconductivity can be induced by the proximity effect of a an s-wave
superconductor (S) into the TI. To probe the superconducting correlations
inside the TI, dI/dV spectroscopy has been performed across such S-TI
interfaces. Both the alloyed BiSbTeSe and the
stoichiometric BiSbTeSe have been used as three dimensional TI. In the case
of BiSbTeSe, the presence of disorder induced
electron-electron interactions can give rise to an additional zero-bias
resistance peak. For the stoichiometric BiSbTeSe with less disorder, tunnel
barriers were employed in order to enhance the signal from the interface. The
general observations in the spectra of a large variety of samples are
conductance dips at the induced gap voltage, combined with an increased sub-gap
conductance, consistent with p-wave predictions. The induced gap voltage is
typically smaller than the gap of the Nb superconducting electrode, especially
in the presence of an intentional tunnel barrier. Additional uncovered
spectroscopic features are oscillations that are linearly spaced in energy, as
well as a possible second order parameter component.Comment: Semiconductor Science and Technology; Special Issue on Hybrid Quantum
Materials and Device
Manipulating electronic states at oxide interfaces using focused micro X-rays from standard lab-sources
Recently, x-ray illumination, using synchrotron radiation, has been used to
manipulate defects, stimulate self-organization and to probe their structure.
Here we explore a method of defect-engineering low-dimensional systems using
focused laboratory-scale X-ray sources. We demonstrate an irreversible change
in the conducting properties of the 2-dimensional electron gas at the interface
between the complex oxide materials LaAlO3 and SrTiO3 by X-ray irradiation. The
electrical resistance is monitored during exposure as the irradiated regions
are driven into a high resistance state. Our results suggest attention shall be
paid on electronic structure modification in X-ray spectroscopic studies and
highlight large-area defect manipulation and direct device patterning as
possible new fields of application for focused laboratory X-ray sources.Comment: 12 pages, 4 figure
Stencil lithography of superconducting contacts on MBE-grown topological insulator thin films
Topological insulator (Bi0.06Sb0.94)2Te3 thin films grown by molecular beam epitaxy have been capped in-situ with a 2 nm Al film to conserve the pristine topological surface states. Subsequently, a shadow mask - structured by means of focus ion beam - was in-situ placed underneath the sample to deposit a thick layer of Al on well-defined microscopically small areas. The 2 nm thin Al layer fully oxidizes after exposure to air and in this way protects the TI surface from degradation. The thick Al layer remains metallic underneath a 3–4 nm thick native oxide layer and therefore serves as (super-) conducting contacts. Superconductor-Topological Insulator-Superconductor junctions with lateral dimensions in the nm range have then been fabricated via an alternative stencil lithography technique. Despite the in-situ deposition, transport measurements and transmission electron microscope analysis indicate a low transparency, due to an intermixed region at the interface between topological insulator thin film and metallic Al
Elimination of T cell reactivity to pancreatic β cells and partial preservation of β cell activity by peptide blockade of LFA-1:ICAM-1 interaction in the NOD mouse model
In insulin dependent diabetes mellitus (T1D), self-reactive T cells infiltrate pancreatic islets and induce beta cell destruction and dysregulation of blood glucose. A goal is to control only the self-reactive T cells, leaving the remainder of the T cell population free to protect the host. One approach is blockade of the second signal for T cell activation while allowing the first (antigen-specific) signal to occur. This work proposes that small peptides that block interaction of second signals delivered through the counter receptors LFA-1:ICAM-1 will induce attacking T cells (receiving the antigen signal) to become anergic or undergo apoptosis. In NOD mice, the peptides eliminated T cell reactivity against pancreatic antigens and reduced cellular infiltration into islets, which retained stronger density of insulin staining at five weeks after cessation of therapy. In in vitro studies the peptides induced nonresponsiveness during activation of T cells from mice and from human peripheral blood