186 research outputs found
Controlling hole spin dynamics in two‐dimensional hole systems at low temperatures
With the recent discovery of very long hole spin decoherence times in GaAs/AlGaAs heterostructures of more than 70 ns
in two-dimensional hole systems, using the hole spin as a viable alternative to electron spins in spintronic applications seems
possible. Furthermore, as the hyperfine interaction with the nuclear spins is likely to be the limiting factor for electron spin
lifetimes in zero dimensions, holes with their suppressed Fermi contact hyperfine interaction due to their p-like nature should
be able to show even longer lifetimes than electrons. For spintronic applications, electric-field control of hole spin dynamics
is desirable.
Here, we report on time-resolved Kerr rotation and resonant spin amplification measurements on a two-dimensional hole
system in a p-doped GaAs/AlGaAs heterostructure. Via a semitransparent gate, we tune the charge density within the sample.
We are able to observe a change in the hole g factor, as well as in the hole spin dephasing time at high magnetic fields
Resonant spin amplification of hole spin dynamics in two‐dimensional hole systems: experiment and simulation
Spins in semiconductor structures may allow for the realization of scalable quantum bit arrays, an essential
component for quantum computation schemes. Specifically, hole spins may be more suited for this purpose than electron
spins, due to their strongly reduced interaction with lattice nuclei, which limits spin coherence for electrons in quantum dots.
Here, we present resonant spin amplification (RSA) measurements, performed on a p-modulation doped GaAs-based quantum
well at temperatures below 500 mK. The RSA traces have a peculiar, butterfly-like shape, which stems from the initialization
of a resident hole spin polarization by optical orientation. The combined dynamics of the optically oriented electron and hole
spins are well-described by a rate equation model, and by comparison of experiment and model, hole spin dephasing times of
more than 70 ns are extracted from the measured data
Field dependence of non-reciprocal magnons in chiral MnSi
Spin waves in chiral magnetic materials are strongly influenced by the
Dzyaloshinskii-Moriya interaction resulting in intriguing phenomena like
non-reciprocal magnon propagation and magnetochiral dichroism. Here, we study
the non-reciprocal magnon spectrum of the archetypical chiral magnet MnSi and
its evolution as a function of magnetic field covering the field-polarized and
conical helix phase. Using inelastic neutron scattering, the magnon energies
and their spectral weights are determined quantitatively after deconvolution
with the instrumental resolution. In the field-polarized phase the imaginary
part of the dynamical susceptibility is shown to
be asymmetric with respect to wavevectors longitudinal to the applied
magnetic field , which is a hallmark of chiral magnetism. In the
helimagnetic phase, becomes increasingly
symmetric with decreasing due to the formation of helimagnon bands
and the activation of additional spinflip and non-spinflip scattering channels.
The neutron spectra are in excellent quantitative agreement with the low-energy
theory of cubic chiral magnets with a single fitting parameter being the
damping rate of spin waves.Comment: Paper: 10 pages, 5 figures Supplement: 8 pages, 11 figure
Face masks suitable for preventing COVID-19 and pollen allergy. A study in the exposure chamber
Background: Since the outbreak of the coronavirus pandemic, the population in Germany has been asked to wear face masks in public areas. The masks are accepted by the public. People with a pollen allergy have an interest in knowing whether masks can also provide protection against pollen and thus prevent symptoms even without medication.
Method: In order to evaluate the potential 'antipollen effect' of face masks, 14 adults with confirmed grass pollen-induced allergic rhinoconjunctivitis were exposed to grass pollen for a period of two hours following a standardised protocol. The test was conducted outside of the grass pollen season. The subjects wore either no mask, a medical mask or a FFP2 mask.
Results: Subjects wearing either mask were clearly able to avoid both nasal and conjunctival symptoms. There were no significant differences between the two masks in terms of effect. Mask wearing to prevent pollen exposure clearly supports overall well-being.
Conclusion: Wearing a mask during pollen season can be recommended as an effective nondrug option for people with a pollen allergy.
Supplementary information: The online version of this article (10.1007/s40629-021-00180-8) contains supplementary material, which is available to authorized users
"WissensWert - Wert des Wissens": Kooperativer Bericht von der ODOK 2012 - 14. Österreichisches Online-Informationstreffen und 15. Österreichischer Dokumentartag in Wels (12.-14. September 2012)
cooperative report of the Austrian library conference ODOK "worth knowing - the worth of knowledge", September 201
Profiling the human response to physical exercise: a computational strategy for the identification and kinetic analysis of metabolic biomarkers
Correlation of EGFR expression, gene copy number and clinicopathological status in NSCLC
Background: Epidermal Growth Factor Receptor (EGFR) targeting therapies are currently of great relevance for the treatment of lung cancer. For this reason, in addition to mutational analysis immunohistochemistry (IHC) of EGFR in lung cancer has been discussed for the decision making of according therapeutic strategies. The aim of this study was to obtain standardization of EGFR-expression methods for the selection of patients who might benefit of EGFR targeting therapies. Methods: As a starting point of a broad investigation, aimed at elucidating the expression of EGFR on different biological levels, four EGFR specific antibodies were analyzed concerning potential differences in expression levels by Immunohistochemistry (IHC) and correlated with fluorescence in situ hybridization (FISH) analysis and clinicopathological data. 206 tumor tissues were analyzed in a tissue microarray format employing immunohistochemistry with four different antibodies including Dako PharmDx kit (clone 2-18C9), clone 31G7, clone 2.1E1 and clone SP84 using three different scoring methods. Protein expression was compared to FISH utilizing two different probes. Results: EGFR protein expression determined by IHC with Dako PharmDx kit, clone 31G7 and clone 2.1E1 (≤ 0.05) correlated significantly with both FISH probes independently of the three scoring methods; best correlation is shown for 31G7 using the scoring method that defined EGFR positivity when ≥ 10% of the tumor cells show membranous staining of moderate and severe intensity (p = 0.001). Conclusion: Overall, our data show differences in EGFR expression determined by IHC, due to the applied antibody. Highest concordance with FISH is shown for antibody clone 31G7, evaluated with score B (p = 0.001). On this account, this antibody clone might by utilized for standard evaluation of EGFR expression by IHC
A Cellular Automaton Framework for Infectious Disease Spread Simulation
In this paper, a cellular automaton framework for processing the spatiotemporal spread of infectious diseases is presented. The developed environment simulates and visualizes how infectious diseases might spread, and hence provides a powerful instrument for health care organizations to generate disease prevention and contingency plans. In this study, the outbreak of an avian flu like virus was modeled in the state of Tyrol, and various scenarios such as quarantine, effect of different medications on viral spread and changes of social behavior were simulated
Survival outcomes in a prospective randomized multicenter Phase III trial comparing patients undergoing anatomical segmentectomy versus standard lobectomy for non-small cell lung cancer up to 2 cm
OBJECTIVES
The oncological equivalence of anatomical segmentectomy for early stage non-small cell lung cancer (NSCLC) is still controversial. Primary aim of this study was survival outcomes in combination with improved quality of life after segmentectomy compared with lobectomy in patients with pathological stage Ia NSCLC (up to 2 cm, 7th edition) MATERIALS AND METHODS: We conducted a prospective, randomized, multicenter phase III trial to confirm the non-inferiority of segmentectomy to lobectomy in regard to prognosis (trial No. DRKS00004897). Patients were randomized to undergo either segmentectomy or lobectomy and followed up for 5-years survival and tumor recurrence. The 5-year hazard ratio comparing lobectomy with segmentectomy was required to remain above 0.5.
RESULTS
Between October 2013 and June 2016, 108 patients with verified or suspected NSCLC up to 2 cm diameter were enrolled; 54 were assigned to lobectomy and 54 (1 drop-out) to segmentectomy. In-hospital and 90 days mortality was 0% in both groups. Overall survival at 5 years was 86.52% in the lobectomy compared to 78.21% in the segmentectomy group (HR = 0.61, (95% CI 0.23-1.66), p-value of non-inferiority test, p-ni = 0.687). Disease free survival was 77.29% for the lobectomy and 77.96% for the segmentectomy patients (HR = 1.50, (95% CI 0.60-3.76), p-ni = 0.019). At a median follow-up of 5 years, no differences were noted in either the locoregional or distant recurrent disease in both groups (9.4% vs 7.4%, p-ni = 0.506).
CONCLUSION
Overall survival, locoregional and distant recurrences was not significantly difference for patients undergoing either segmentectomy or lobectomy for stage Ia NSCLC. The targeted non-inferiority of segmentectomy to lobectomy could not be proven for primary endpoint overall survival, but was significant for the secondary endpoint of disease free survival
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