Lithium Diffusion in Ion-Beam Sputtered Amorphous LiAlO2

We investigated lithium self-diffusion in amorphous lithium aluminate (LiAlO2) layers between room temperature and 473 K. For the experiments, amorphous 6LiAlO2 (30 nm)/7LiAlO2 (1200 nm) isotope hetero-structures were deposited by ion-beam sputtering on sapphire substrates. Diffusion profiles were analysed by secondary ion mass spectrometry (SIMS). The results show that the diffusivities obey the Arrhenius law with an activation enthalpy of (0.94 ± 0.02) eV. This is not much different to the activation enthalpy of 1.14 eV found for LiAlO2 single crystals by impedance spectroscopy. It rationalizes the only modest enhancement of diffusivities in amorphous lithium aluminate compared to single crystals of three to five orders of magnitude in the temperature range studied, when compared with, e.g., lithium niobate. © 2015 Walter de Gruyter

Patient motivation as a predictor of digital health intervention effects: A meta-epidemiological study of cancer trials

The objective of this meta-epidemiological study was to develop a rating that captures participants’ motivation at the study level in digital health intervention (DHI) randomised controlled trials (RCTs). The rating was used to investigate whether participants’ motivation is associated with the effect estimates in DHI RCTs for cancer patients. The development of the rating was based on a bottom-up approach involving the collection of information that captures participants’ baseline motivation in empirical studies from the Smartphone-RCCT Database. We specified three indicators for rating: indicator 1 captures whether the study team actively selects or enhances the motivation of the potential study participants; indicator 2 captures the study participants’ active engagement before the treatment allocation; and indicator 3 captures the potential bond and trust between the study participants and the person/institution referring to the study. The rating of each indicator and the overall rating varies between high motivation, moderate motivation, and low motivation. We applied the rating across 27 DHI RCTs with cancer patients. We performed meta-regression analysis to examine the effect of patient motivation on quality of life (QoL), psychological outcomes, and attrition. The intraclass correlation coefficient (ICC) indicated moderate to poor inter-rater reliability. The meta-regression showed that cancer patients’ overall motivation before engaging in the intervention was associated with the treatment effect of QoL. Patient motivation was not found to be associated with psychological outcomes or attrition. Subgroup analyses revealed that the clinical effects of DHIs were more prevalent in the high-motivation subgroups, whereas the low-motivation subgroups were unlikely to show intervention benefits. The likelihood of dropouts from DHIs seems to be especially high among the low-bond (indicator 3) subgroup. We suggest using single indicators since they reflect specific content. Better reporting about baseline motivation is required to enable meaningful interpretations in not only primary studies but also in evidence syntheses

NMR and Impedance Spectroscopy Studies on Lithium Ion Diffusion in Microcrystalline γ-LiAlO2

In this work nuclear magnetic resonance (NMR) and impedance spectroscopy (IS) studies on Li ion dynamics in microcrystalline γ-LiAlO2 are presented. The sample was prepared by solid state synthesis between Li2CO3 and Al2O3 in air, followed by a quenching procedure. The presence of phase-pure γ-LiAlO2 was confirmed by X-ray powder diffraction including Rietveld refinement. Further structural characterization was done with 6Li, 7Li and 27Al NMR. Several NMR techniques such as spin-lattice relaxation measurements, motional narrowing experiments, as well as spin-alignment echo were employed for the investigation of Li ion diffusion. The measurements were carried out at high temperatures (up to 970 K) in order to access the regime of Li ion motion being very slow. The dc conductivities measured by IS in the temperature range from 680 K to 870 K were converted to diffusion coefficients being compatible with those obtained by NMR. © 2015 Walter de Gruyter

Local Ion Dynamics in Polycrystalline β-LiGaO2: A Solid-State NMR Study

Solid-state nuclear magnetic resonance spectroscopy is an efficient technique to characterize dynamics and structure of materials. It has been widely used to elucidate ion dynamics in lithium ion conductors. Fast moving lithium ions are needed in energy storage devices, whereas slow ion motion is exploited in some materials used, for example, as blankets in fusion reactors. β-lithium gallium oxide (LiGaO2) is a slow Li+ ionic conductor similar to γ-lithium aluminum oxide (LiAlO2). In an ion conductor, in addition to the main diffusion process, localized motions (to-and-fro jumps) may be present. In the present work, with the help of solid-state NMR experiments, we report on the localized movements of Li+ ionic species in β-LiGaO2 in the temperature range between 300 K and 450 K. In this work, we have mainly extracted the peculiarities of ion dynamics from 7Li spin-alignment echo NMR measurements and the observation of the motional narrowing of the central transition signal of 7Li. © 2017 Walter de Gruyter GmbH, Berlin/Boston 2017

The New IDS Corpus Analysis Platform: Challenges and Prospects

The present article describes the first stage of the KorAP project, launched recently at the Institut für Deutsche Sprache (IDS) in Mannheim, Germany. The aim of this project is to develop an innovative corpus analysis platform to tackle the increasing demands of modern linguistic research. The platform will facilitate new linguistic findings by making it possible to manage and analyse primary data and annotations in the petabyte range, while at the same time allowing an undistorted view of the primary linguistic data, and thus fully satisfying the demands of a scientific tool. An additional important aim of the project is to make corpus data as openly accessible as possible in light of unavoidable legal restrictions, for instance through support for distributed virtual corpora, user-defined annotations and adaptable user interfaces, as well as interfaces and sandboxes for user-supplied analysis applications. We discuss our motivation for undertaking this endeavour and the challenges that face it. Next, we outline our software implementation plan and describe development to-date

Evaluation of a portable retinal imaging device: towards a comparative quantitative analysis for morphological measurements of retinal blood vessels

This study investigated the possibility of using low-cost, handheld, retinal imaging devices for the automatic extraction of quantifiable measures of retinal blood vessels. Initially, the available handheld devices were compared using a Zeiss model eye incorporating a USAF resolution test chart to assess their optical properties. The only suitable camera of the five evaluated was the Horus DEC 200. This device was then subjected to a detailed evaluation in which images in human eyes taken from the handheld camera were compared in a quantitative analysis with those of the same eye from a Canon CR-DGi retinal desktop camera. We found that the Horus DEC 200 exhibited shortcomings in capturing images of human eyes by comparison with the Canon. More images were rejected as being unevaluable or suffering failures in automatic segmentation than with the Canon, and even after exclusion of affected images, the Horus yielded lower measurements of vessel density than the Canon. A number of issues affecting handheld cameras in general and some features of the Horus in particular have been identified that might contribute to the observed differences in performance. Some potential mitigations are discussed which might yield improvements in performance, thus potentially facilitating use of handheld retinal imaging devices for quantitative retinal microvascular measurements

Slow Lithium Transport in Metal Oxides on the Nanoscale

This article reports on Li self-diffusion in lithium containing metal oxide compounds. Case studies on LiNbO3, Li3NbO4, LiTaO3, LiAlO2, and LiGaO2 are presented. The focus is on slow diffusion processes on the nanometer scale investigated by macroscopic tracer methods (secondary ion mass spectrometry, neutron reflectometry) and microscopic methods (nuclear magnetic resonance spectroscopy, conductivity spectroscopy) in comparison. Special focus is on the influence of structural disorder on diffusion. © 2017 Walter de Gruyter GmbH, Berlin/Boston