391 research outputs found
Critical thickness and orbital ordering in ultrathin La0.7Sr0.3MnO3 films
Detailed analysis of transport, magnetism and x-ray absorption spectroscopy
measurements on ultrathin La0.7Sr0.3MnO3 films with thicknesses from 3 to 70
unit cells resulted in the identification of a lower critical thickness for a
non-metallic, non-ferromagnetic layer at the interface with the SrTiO3 (001)
substrate of only 3 unit cells (~12 Angstrom). Furthermore, linear dichroism
measurements demonstrate the presence of a preferred (x2-y2) in-plane orbital
ordering for all layer thicknesses without any orbital reconstruction at the
interface. A crucial requirement for the accurate study of these ultrathin
films is a controlled growth process, offering the coexistence of
layer-by-layer growth and bulk-like magnetic/transport properties.Comment: 22 pages, 6 figures, accepted for publication in Physical Review
PMH29 SWITCHING FROM BRANDED TO GENERIC RISPERIDONE IN PATIENTS WITH SCHIZOPHRENIA: AN ESTIMATION OF POTENTIAL ECONOMIC CONSEQUENCES IN THE NETHERLANDS
Determination of the spin-flip time in ferromagnetic SrRuO3 from time-resolved Kerr measurements
We report time-resolved Kerr effect measurements of magnetization dynamics in
ferromagnetic SrRuO3. We observe that the demagnetization time slows
substantially at temperatures within 15K of the Curie temperature, which is ~
150K. We analyze the data with a phenomenological model that relates the
demagnetization time to the spin flip time. In agreement with our observations
the model yields a demagnetization time that is inversely proportional to T-Tc.
We also make a direct comparison of the spin flip rate and the Gilbert damping
coefficient showing that their ratio very close to kBTc, indicating a common
origin for these phenomena
Enhanced piezoelectric properties of (110)-oriented PbZr1âxTixO3 epitaxial thin films on silicon substrates at shifted morphotropic phase boundary
Piezoelectrical, ferroelectrical, and structural properties of epitaxial pseudocubic (110)pc oriented 500ânm thick PbZr1âxTixO3 thin films, prepared by pulsed laser deposition on (001) silicon substrates, were measured as a function of composition. The dependence of the measurement data on the Ti content is explained by an abrupt transition from the rhombohedral r-phase to the tetragonal (c/a) 45 phase for xâ ââ 0.6, indicating a shift of the Morphotropic Phase Boundary to this value, where the effective piezoelectric coefficient e3 1 ,eff and dielectric constant Δ33 ,eff reach their maximum values. These findings are of great significance for Si-based piezo-micro electro mechanical systems, in particular energy harvesters. The largest value of the figure-of-merit for such devices was found for xâ =â0.6, FOM=24.0âGP
Group based prenatal care in a low-and high risk population in the Netherlands: a study protocol for a stepped wedge cluster randomized controlled trial
Background. CenteringPregnancy (CP) is a multifaceted group based care-model integrated in routine prenatal care, combining health assessment, education, and support. CP has shown some positive results on perinatal outcomes. However, the effects are less obvious when limited to the results of randomized controlled trials: as there are few trials and there is a variation in reported outcomes. Furthermore, former research was mostly conducted in the United States of America and in specific (often high risk) populations. Our study aims to evaluate the effects of CP in the Netherlands in a general population of pregnant women (low and high risk). Furthermore we aim to explore the mechanisms leading to the eventual effects by measuring potential mediating factors. Design. We will perform a stepped wedge cluster randomized controlled trial, in a Western region in the Netherlands. Inclusion criteria are <24 weeks of gestation and able to communicate in Dutch (with assistance). Women in the control period will receive individual care, women in the intervention period (starting at the randomized time-point) will be offered the choice between individual care or CP. Primary outcomes are maternal and neonatal morbidity, retrieved from a national routine database. Secondary outcomes are health behavior, psychosocial outcomes, satisfaction, health care utilization and process outcomes, collected through self-administered questionnaires, group-evaluations and individual interviews. We will conduct intention-to-treat analyses. Also a per protocol analysis will be performed comparing the three subgroups: control group, CP-participants and non-CP-participants, using multilevel techniques to account for clustering effects. Discussion. This study contributes to the evidence regarding the effect of CP and gives a first indication of the effect and implementation of CP in both low and high-risk pregnancies in a high-income Western society other than the USA. Also, measuring factors that are hypothesized to mediate the effect of CP will enable to explain the mechanisms that lead to effects on maternal and neonatal outcomes. Trial registration. Dutch Trial Register, NTR4178, registered September 17th 2013
Management of cerebral azole-resistant Aspergillus fumigatus infection : a role for intraventricular liposomal-amphotericin B
Objectives: In the pre-azole era, central nervous system (CNS) infections with Aspergillus had a dismal outcome. Survival improved with voriconazole but CNS infections caused by azole-resistant Aspergillus fumigatus preclude its use. Intravenous liposomal-amphotericin B (L-AmB) is the preferred treatment option for azole-resistant CNS infections but has suboptimal brain concentrations. Methods: We describe three patients with biopsy-proven CNS aspergillosis where intraventricular L-AmB was added to systemic therapy. Two patients with azole-resistant aspergillosis and one patient with azole-susceptible CNS aspergillosis were treated with intraventricular L-AmB at a dose of 1 mg weekly. Results: We describe three patients successfully treated with a combination of intravenous and intraventricular L-AmB. All three patients survived but one patient developed serious headaches, most likely not related to this treatment. Conclusions: Intraventricular L-AmB may have a role in the treatment of therapy-refractory CNS aspergillosis when added to systemic therapy. (C) 2020 The Author(s). Published by Elsevier Ltd on behalf of International Society for Antimicrobial Chemotherapy
Parallel electron-hole bilayer conductivity from electronic interface reconstruction
The perovskite SrTiO-LaAlO structure has advanced to a model system
to investigate the rich electronic phenomena arising at polar interfaces. Using
first principles calculations and transport measurements we demonstrate that an
additional SrTiO capping layer prevents structural and chemical
reconstruction at the LaAlO surface and triggers the electronic
reconstruction at a significantly lower LaAlO film thickness than for the
uncapped systems. Combined theoretical and experimental evidence (from
magnetotransport and ultraviolet photoelectron spectroscopy) suggests two
spatially separated sheets with electron and hole carriers, that are as close
as 1 nm.Comment: Phys. Rev. Lett., in pres
Magnetic effects at the interface between nonmagnetic oxides
The electronic reconstruction at the interface between two insulating oxides
can give rise to a highly-conductive interface. In analogy to this remarkable
interface-induced conductivity we show how, additionally, magnetism can be
induced at the interface between the otherwise nonmagnetic insulating
perovskites SrTiO3 and LaAlO3. A large negative magnetoresistance of the
interface is found, together with a logarithmic temperature dependence of the
sheet resistance. At low temperatures, the sheet resistance reveals magnetic
hysteresis. Magnetic ordering is a key issue in solid-state science and its
underlying mechanisms are still the subject of intense research. In particular,
the interplay between localized magnetic moments and the spin of itinerant
conduction electrons in a solid gives rise to intriguing many-body effects such
as Ruderman-Kittel-Kasuya-Yosida (RKKY) interactions, the Kondo effect, and
carrier-induced ferromagnetism in diluted magnetic semiconductors. The
conducting oxide interface now provides a versatile system to induce and
manipulate magnetic moments in otherwise nonmagnetic materials.Comment: Nature Materials, July issu
Induction of labor with Foley catheter and risk of subsequent preterm birth : followâup study of two randomized controlled trials (PROBAATâ1 and â2)
Acknowledgements We thank all the women who participated in the PROBAAT trials and all participating institutions and their staff for their contribution to this follow-up study. Funding The original PROBAAT-2 trial was funded by FondsNutsOhra. For the PROBAAT-1 trial and this follow-up study, no funding was received. MV received a doctoral grant for teachers by the Netherlands Organisation for Scientific Research (023.011.051). BM is supported by a NHMRC Practitioner Fellowship (GNT1082548). Funding sources had no role in design, execution, analyses, interpretation, or decision to submit results.Peer reviewedPublisher PD
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