Micromagnetic simulations of persistent oscillatory modes excited by spin-polarized current in nanoscale exchange-biased spin valves

We perform 3D micromagnetic simulations of current-driven magnetization dynamics in nanoscale exchange biased spin-valves that take account of (i) back action of spin-transfer torque on the pinned layer, (ii) non-linear damping and (iii) random thermal torques. Our simulations demonstrate that all these factors significantly impact the current-driven dynamics and lead to a better agreement between theoretical predictions and experimental results. In particular, we observe that, at a non-zero temperature and a sub-critical current, the magnetization dynamics exhibits nonstationary behaviour in which two independent persistent oscillatory modes are excited which compete for the angular momentum supplied by spin-polarized current. Our results show that this multi-mode behaviour can be induced by combined action of thermal and spin transfer torques.Comment: 7pages, 2 figures, submitted JAP via MMM 200

Sevoflurane and cardioprotection

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Time domain study of frequency-power correlation in spin-torque oscillators

This paper describes a numerical experiment, based on full micromagnetic simulations of current-driven magnetization dynamics in nanoscale spin valves, to identify the origins of spectral linewidth broadening in spin torque oscillators. Our numerical results show two qualitatively different regimes of magnetization dynamics at zero temperature: regular (single-mode precessional dynamics) and chaotic. In the regular regime, the dependence of the oscillator integrated power on frequency is linear, and consequently the dynamics is well described by the analytical theory of current-driven magnetization dynamics for moderate amplitudes of oscillations. We observe that for higher oscillator amplitudes, the functional dependence of the oscillator integrated power as a function of frequency is not a single-valued function and can be described numerically via introduction of nonlinear oscillator power. For a range of currents in the regular regime, the oscillator spectral linewidth is a linear function of temperature. In the chaotic regime found at large current values, the linewidth is not described by the analytical theory. In this regime we observe the oscillator linewidth broadening, which originates from sudden jumps of frequency of the oscillator arising from random domain wall nucleation and propagation through the sample. This intermittent behavior is revealed through a wavelet analysis that gives superior description of the frequency jumps compared to several other techniques.Comment: 11 pages, 4 figures to appear in PR

Allogeneic peripheral blood stem cell transplantation with reduced intensity conditioning in primary refractory prolymphocytic leukemia: graft-versus-leukemia effect without graft-versus-host disease

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Current Trends in Urinary Diversion in Men

Prior to the introduction of the ileal conduit more than four decades ago, the options for urinary diversion after cystectomy were extremely limited. Direct cutaneous anastomoses of the collecting system (cutaneous pyelostomies, ureterostomies) offered patients a short-term diversion, but the benefits were outweighed by significant complications: recession or stenosis of the stoma. The first choice of diversion was the ureterosigmoidostomy with or without antireflux technique. Then it fell in popularity and was replaced with continent/non-continent uretero-ileo-cutaneous diversions. Only in the last years the continent orthotopic neobladder has been widely employed as first procedure choice. At present, patients can be offered a non-continent cutaneous diversion, a continent cutaneous diversion or an orthotopic neobladder urinary reconstructio

PP020—Effects of aripiprazole and risperidone on ventricular repolarization in children and adolescents

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Evaluation of acute cardiovascular effects of immediate-release methylphenidate in children and adolescents with attention-deficit hyperactivity disorder

Attention-deficit hyperactivity disorder is a frequent condition in children and often extends into adulthood. Use of immediate-release methylphenidate (MPH) has raised concerns about potential cardiovascular adverse effects within a few hours after administration. This study was carried out to investigate acute effects of MPH on electrocardiogram (ECG) in a pediatric population. A total of 54 consecutive patients with attention-deficit hyperactivity disorder (51 males and 3 females; mean age =12.14±2.6 years, range 6–19 years), receiving a new prescription of MPH, underwent a standard ECG 2 hours before and after the administration of MPH 10 mg per os. Basal and posttreatment ECG parameters, including mean QT (QT interval when corrected for heart rate [QTc]), QTc dispersion (QTd) interval duration, T-peak to T-end (TpTe) intervals, and TpTe/QT ratio were compared. Significant modifications of both QTc and QTd values were not found after drug administration. QTd fluctuated slightly from 25.7±9.3 milliseconds to 25.1±8.4 milliseconds; QTc varied from 407.6±12.4 milliseconds to 409.8±12.7 milliseconds. A significant variation in blood pressure (systolic blood pressure 105.4±10.3 vs 109.6±11.5; P<0.05; diastolic blood pressure 59.2±7.1 vs 63.1±7.9; P<0.05) was observed, but all the data were within normal range. Heart rate moved from 80.5±15.5 bpm to 87.7±18.8 bpm. No change in TpTe values was found, but a statistically significant increase in TpTe/QTc intervals was found with respect to basal values (0.207±0.02 milliseconds vs 0.214±0.02 milliseconds; P<0.01). The findings of this study show no significant changes in ECG parameters. TpTe values can be an additional parameter to evaluate borderline cases

Disturbo dello Spettro Autistico e Sindrome Psicotica Attenuata: caratteristiche cliniche, neurofisiologiche e rischio di conversione al follow-up

Negli ultimi anni sono stati fatti importanti passi avanti nella comprensione della complessa relazione che intercorre tra Disturbo dello Spettro Autistico (ASD) e i Disturbi dello Spettro della Schizofrenia (SSDs). In particolare, vista la possibilità di co-occorrenza tra le due condizioni, nel corso degli ultimi anni sono aumentati gli studi volti ad esplorare le caratteristiche comuni e distintive tra la sintomatologia autistica e i sintomi psicotici, soprattutto nelle fasi precoci. Infatti, il riconoscimento di uno stato mentale a rischio per psicosi appare estremamente difficoltoso nella popolazione autistica a causa dei numerosi aspetti di sovrapposizione clinica delle due condizioni e alla ridotta disponibilità di strumenti diagnostici per il riconoscimento dei sintomi prodromici specificatamente disegnati per la popolazione ASD. Inoltre, rimane ancora poco chiaro se la presenza di sintomatologia autistica possa rappresentare un fattore di rischio per l’evoluzione verso una psicosi franca. Lo scopo di questa trattazione è dunque quello di fornire una panoramica delle evidenze attualmente disponibili nella letteratura scientifica in merito alla caratteriz- zazione clinica della sintomatologia psicotica prodromica nella popolazione con ASD, sul rischio di conversione in psicosi degli individui ASD che presentano uno stato mentale a rischio e sulle possibili caratteristiche neurofisiologiche comuni tra le due condizioni

One-year follow-up diagnostic stability of autism spectrum disorder diagnosis in a clinical sample of children and toddlers

Some studies show that the diagnosis of Autism Spectrum Disorder could be considered reliable and stable in children aged 18 to 24 months. Nevertheless, the diagnostic stability of early ASD diagnosis has not yet been fully demonstrated. This observational study examines the one-year diagnostic stability of autism spectrum disorder diagnosis in a clinical sample of 147 children diagnosed between 18 and 48 months of age. The ADOS-2 scores were used in order to stratify children in three levels of symptom severity: Autism (AD; comparison score 5–7), Autism Spectrum Disorder (ASD; comparison score 3–4), and Sub-Threshold Symptoms; (STS; comparison score 1–2). Results: Overall, the largest part of children and toddlers diagnosed with autism spectrum disorder between 18 and 48 months continued to show autistic symptoms at one-year follow-up evaluation. Neverthe-less, a significant percentage of children with higher ADOS severity scores exhibited a reduction of symptom severity and, therefore, moved towards a milder severity class one year later. Conversely, the number of subjects of the STS group meaningfully increased. Therefore, at one-year follow-up a statistically significant (χ2 (2) = 181.46, p < 0.0001) percentage of subjects (25.2% of the total) who had received a categorical diagnosis of Autistic Disorder or Autism Spectrum Disorder in baseline no longer met the criteria for a categorical diagnosis. Furthermore, children who no longer met the criteria for autism spectrum disorder continue to show delays in one or more neurodevelopmental areas, possibly related to the emergence of other neurodevelopmental/neuropsychiatric disorders. Overall, the comprehensive results of the study account for a high sensibility but a moderate stability of ASD early diagnosis