585 research outputs found

    Thermal stability of ultrasoft Fe–Zr–N films

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    The thermal stability of nanocrystalline ultrasoft magnetic (Fe98Zr2)1−xNx films with x = 0.10–0.25 was studied using thermal desorption spectrometry, positron beam analysis and high resolution transmission electron microscopy. The results demonstrate that grain growth during the heat treatment is accompanied by an increase of the free volume and nitrogen relocation and desorption. All these phenomena can drastically degrade the ultrasoft magnetic properties. The nitrogen desorption has already started at temperatures around 400 K. Nevertheless, most of the nitrogen leaves the sample at a temperature above 800 K. We found that nitrogen out-diffusion is significantly retarded compared with the prediction of the diffusion in bulk α-Fe. A qualitative model is proposed in which the nitrogen out-diffusion in nanocrystalline material is retarded by trapping at immobile defects, namely Zr atoms, and also by voids at grain boundaries. From a certain temperature, nitrogen migrates from the interior of the nanograins to the nanovoids at the grain boundaries and the out-diffusion to the outer surface is controlled by transport between the voids.

    Nonverbal Switching Ability of Monolingual and Bilingual Children with and without Developmental Language Disorder

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    Bilingualism is associated with enhanced switching skills, while a developmental language disorder (DLD) may negatively impact switching ability. However, both studies with bilinguals as well as studies including children with DLD have revealed mixed results. Moreover, the interaction of bilingualism and DLD has not been addressed and the origin of the stronger or weaker switching performance is unknown. The current study aimed to fill these gaps. Monolingual and bilingual children with and without DLD (n = 32 in each of the four groups) completed a nonverbal color/shape switching task when they were 7 to 8 years old, and a Continuous Performance Task two years earlier. The latter tapped into their response inhibition and sustained attention skills, which may underlie switching ability. No differences between monolinguals and bilinguals were found on the switching task. Children with DLD had higher mixing costs than peers without DLD, which was driven by differences in sustained attention skills. These results add to the body of research indicating that the cognitive advantages of bilingualism are unstable. Additionally, the results substantiate the hypothesis that attention processes are foundational for complex cognitive skills, such as switching, and suggest cascading effects for children with weaker attention skills, such as children with DLD

    The contemporary pulmonary artery catheter. Part 1:placement and waveform analysis

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    Nowadays, the classical pulmonary artery catheter (PAC) has an almost 50-year-old history of its clinical use for hemodynamic monitoring. In recent years, the PAC evolved from a device that enabled intermittent cardiac output measurements in combination with static pressures to a monitoring tool that provides continuous data on cardiac output, oxygen supply and-demand balance, as well as right ventricular (RV) performance. In this review, which consists of two parts, we will introduce the difference between intermittent pulmonary artery thermodilution using cold bolus injections, and the contemporary PAC enabling continuous measurements by using a thermal filament which at random heats up the blood. In this first part, the insertion techniques, interpretation of waveforms of the PAC, the interaction of waveforms with the respiratory cycle and airway pressure as well as pitfalls in waveform analysis are discussed. The second part will cover the measurements of the contemporary PAC including measurement of continuous cardiac output, RV ejection fraction, end-diastolic volume index, and mixed venous oxygen saturation. Limitations of all of these measurements will be highlighted there as well. We conclude that thorough understanding of measurements obtained from the PAC are the first step in successful application of the PAC in daily clinical practice

    What risk factors for Developmental Language Disorder can tell us about the neurobiological mechanisms of language development

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    Language is a complex multidimensional cognitive system that is connected to many neurocognitive capacities. The development of language is therefore strongly intertwined with the development of these capacities and their neurobiological substrates. Consequently, language problems, for example those of children with Developmental Language Disorder (DLD), are explained by a variety of etiological pathways and each of these pathways will be associated with specific risk factors. In this review, we attempt to link previously described factors that may interfere with language development to putative underlying neurobiological mechanisms of language development, hoping to uncover openings for future therapeutical approaches or interventions that can help children to optimally develop their language skills

    The Reduction in Right Ventricular Longitudinal Contraction Parameters Is Not Accompanied by a Reduction in General Right Ventricular Performance During Aortic Valve Replacement:An Explorative Study

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    Objective: The aim of the present study was to identify whether the decrease of longitudinal parameters after cardiothoracic surgery (ie, tricuspid annular systolic plane excursion [TAPSE] and systolic excursion velocity [S']) is accompanied by a reduction in global right ventricular (RV) performance. Design: Prospective, observational study. Setting: Single-center explorative study in a tertiary teaching hospital. Participants: The study comprised 20 patients who underwent aortic valve replacement with or without coronary artery bypass grafting. Interventions: During cardiac surgery, simultaneous measurements of RV function were performed with a pulmonary artery catheter and transesophageal echocardiography. Measurements and Main Results: TAPSE and S’ were reduced significantly directly after surgery compared with the time before surgery (TAPSE from 20.8 [16.6-23.4] mm to 9.1 [5.6-15.5] mm; p < 0.001 and S’ from 8.7 [7.9-10.7] cm/s to 7.2 [5.7-8.6] cm/s; p = 0.041). However, the reduction in TAPSE and S’ was not accompanied by a reduction in RV performance, as assessed with the TEE-derived myocardial performance index (MPI) and pulmonary artery catheter–derived RV ejection fraction (RVEF). Both remained statistically unaltered before and after the procedure (MPI from 0.52 [0.43-0.58] to 0.50 [0.42-0.88]; p = 0.278 and RVEF from 27% [22%-32%] to 26% [22%-28%]; p = 0.294). Conclusions: In the direct postoperative phase, the reduction of echocardiographic parameters of longitudinal RV contractility (TAPSE and S’) were not accompanied by a reduction in global RV performance, expressed as MPI and RVEF. Solely relying on a single RV parameter as a marker for global RV performance may not be adequate to assess the complex adaptation of the right ventricle to aortic valve replacement
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