585 research outputs found
Thermal stability of ultrasoft Fe–Zr–N films
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
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
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
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A Quasi-Universal Nonword Repetition Task as a Diagnostic Tool for Bilingual Children Learning Dutch as a Second Language.
PURPOSE: This study evaluated a newly developed quasi-universal nonword repetition task (Q-U NWRT) as a diagnostic tool for bilingual children with language impairment (LI) who have Dutch as a 2nd language. The Q-U NWRT was designed to be minimally influenced by knowledge of 1 specific language in contrast to a language-specific NWRT with which it was compared. METHOD: One hundred twenty monolingual and bilingual children with and without LI participated (30 per group). A mixed-design analysis of variance was used to investigate the effects of LI and bilingualism on the NWRTs. Receiver operating characteristic analyses were conducted to evaluate the instruments' diagnostic value. RESULTS: Large negative effects of LI were found on both NWRTs, whereas negative effects of bilingualism only occurred on the language-specific NWRT. Both instruments had high clinical accuracy in the monolingual group, but only the Q-U NWRT had high clinical accuracy in the bilingual group. CONCLUSIONS: This study indicates that the Q-U NWRT is a promising diagnostic tool to help identify LI in bilingual children learning Dutch as a 2nd language. The instrument was clinically accurate in both a monolingual and bilingual group of children and seems better able to disentangle LI from language disadvantage than more language-specific measures
What risk factors for Developmental Language Disorder can tell us about the neurobiological mechanisms of language development
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
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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