Adsorption of Cu, Ag, and Au atoms on graphene including van der Waals interactions

We performed a systematic density functional study of the adsorption of copper, silver, and gold adatoms on graphene, especially accounting for van der Waals interactions by the vdW-DF and the PBE+D2 methods. In particular, we analyze the preferred adsorption site (among top, bridge, and hollow positions) together with the corresponding distortion of the graphene sheet and identify diffusion paths. Both vdW schemes show that the coinage metal atoms do bind to the graphene sheet and that in some cases the buckling of the graphene can be significant. The results for silver are at variance with those obtained with GGA, which gives no binding in this case. However, we observe some quantitative differences between the vdW-DF and the PBE+D2 methods. For instance the adsorption energies calculated with the PBE+D2 method are systematically higher than the ones obtained with vdW-DF. Moreover, the equilibrium distances computed with PBE+D2 are shorter than those calculated with the vdW-DF method

Early indication of decompensated heart failure in patients on home-telemonitoring: a comparison of prediction algorithms based on daily weight and noninvasive transthoracic bio-impedance

Background: Heart Failure (HF) is a common reason for hospitalization. Admissions might be prevented by early detection of and intervention for decompensation. Conventionally, changes in weight, a possible measure of fluid accumulation, have been used to detect deterioration. Transthoracic impedance may be a more sensitive and accurate measure of fluid accumulation. Objective: In this study, we review previously proposed predictive algorithms using body weight and noninvasive transthoracic bio-impedance (NITTI) to predict HF decompensations. Methods: We monitored 91 patients with chronic HF for an average of 10 months using a weight scale and a wearable bio-impedance vest. Three algorithms were tested using either simple rule-of-thumb differences (RoT), moving averages (MACD), or cumulative sums (CUSUM). Results: Algorithms using NITTI in the 2 weeks preceding decompensation predicted events (P<.001); however, using weight alone did not. Cross-validation showed that NITTI improved sensitivity of all algorithms tested and that trend algorithms provided the best performance for either measurement (Weight-MACD: 33%, NITTI-CUSUM: 60%) in contrast to the simpler rules-of-thumb (Weight-RoT: 20%, NITTI-RoT: 33%) as proposed in HF guidelines. Conclusions: NITTI measurements decrease before decompensations, and combined with trend algorithms, improve the detection of HF decompensation over current guideline rules; however, many alerts are not associated with clinically overt decompensation

LuxTrace: indoor positioning using building illumination

Tracking location is challenging due to the numerous constraints of practical systems including, but not limited to global cost, device volume and weight, scalability and accuracy; these constraints are typically more severe for systems that should be wearable and used indoors. We investigate the use of wearable solar cells to track changing light conditions (a concept that we named LuxTrace) as a source of user displacement and activity data. We evaluate constraints of this approach and present results from an experimental validation of displacement and activity estimation. The results indicate that a distance estimation accuracy of 21cm (80% quantile) can be achieved. A simple method to combine LuxTrace with complementary absolute location estimation methods is also presented. We apply carpet-like distributed RFID tags to demonstrate online learning of new lighting environment

Hydrogen site occupancy and strength of forces in nano-sized metal hydrides

The dipole force components in nano-sized metal hydrides are quantitatively determined with curvature and x-ray diffraction measurements. Ab-initio density functional theory is used to calculate the dipole components and the symmetry of the strain field. The hydrogen occupancy in a 100 nm thick V film is shown to be tetrahedral with a slight asymmetry at low concentration and a transition to octahedral occupancy is shown to take place at around 0.07 [H/V] at 360 K. When the thickness of the V layer is reduced to 3 nm and biaxially strained, in a Fe_0.5V_0.5/V superlattice, the hydrogen unequivocally occupies octahedral z-like sites, even at and below concentrations of 0.02 [H/V]

Characterizing infection in anti-neutrophil cytoplasmic antibody-associated vasculitis:results from a longitudinal, matched-cohort data linkage study

Objectives: Infection exerts a major burden in ANCA-associated vasculitis (AAV), however, its precise extent and nature remains unclear. In this national study we aimed to longitudinally quantify, characterize and contextualize infection risk in AAV. Methods: We conducted a multicentre matched cohort study of AAV. Complementary data on infections were retrieved via data linkage with the population-based Scottish microbiological laboratory, hospitalization and primary care prescribing registries. Results: A total of 379 AAV patients and 1859 controls were followed up for a median of 3.5 years (interquartile range 1.9-5.7). During follow-up, the proportions of AAV patients with at least one laboratory-confirmed infection, severe infection and primary care antibiotic prescription were 55.4%, 35.6% and 74.6%, respectively. The risk of infection was higher in AAV than in matched controls {laboratory-confirmed infections: incidence rate ratio [IRR] 7.3 [95% confidence interval (CI) 5.6, 9.6]; severe infections: IRR 4.4 [95% CI 3.3, 5.7]; antibiotic prescriptions: IRR 2.2 [95% CI 1.9, 2.6]}. Temporal trend analysis showed that AAV patients remained at a higher risk of infections throughout the follow-up period, especially year 1. Although the Escherichia genus was the most commonly identified pathogen (16.6% of AAV, 5.5% of controls; P &lt; 0.0001), AAV patients had the highest risk for Herpes [IRR 12.5 (95% CI 3.7, 42.6)] and Candida [IRR 11.4 (95% CI 2.4, 55.4)]. Conclusion: AAV patients have up to seven times higher risk of infection than the general population and the overall risk remains significant after 8 years of follow-up. The testing of enhanced short- to medium-term prophylactic antibiotic regimes should be considered.</p

Early indication of decompensated heart failure in patients on home-telemonitoring: a comparison of prediction algorithms based on daily weight and noninvasive transthoracic bio-impedance.

Heart Failure (HF) is a common reason for hospitalization. Admissions might be prevented by early detection of and intervention for decompensation. Conventionally, changes in weight, a possible measure of fluid accumulation, have been used to detect deterioration. Transthoracic impedance may be a more sensitive and accurate measure of fluid accumulation.In this study, we review previously proposed predictive algorithms using body weight and noninvasive transthoracic bio-impedance (NITTI) to predict HF decompensations.We monitored 91 patients with chronic HF for an average of 10 months using a weight scale and a wearable bio-impedance vest. Three algorithms were tested using either simple rule-of-thumb differences (RoT), moving averages (MACD), or cumulative sums (CUSUM).Algorithms using NITTI in the 2 weeks preceding decompensation predicted events (P<.001); however, using weight alone did not. Cross-validation showed that NITTI improved sensitivity of all algorithms tested and that trend algorithms provided the best performance for either measurement (Weight-MACD: 33%, NITTI-CUSUM: 60%) in contrast to the simpler rules-of-thumb (Weight-RoT: 20%, NITTI-RoT: 33%) as proposed in HF guidelines.NITTI measurements decrease before decompensations, and combined with trend algorithms, improve the detection of HF decompensation over current guideline rules; however, many alerts are not associated with clinically overt decompensation

Physico-chemical properties of extrudates and their relation to lipid incorporation and lipid oxidation

Extrusion cooking is a key technology in food processing used to produce a wide range of products and extrudates such as cereals, cornflakes and snacks. In addition, extrusion plays a central role in the production of animal food. The oxidation of lipids in extrudates is problematic as this is associated with considerable quality deteriorations. Most conspicuous is the rancid off-flavour. Lipids can interact differently with the matrix in an extrudate and be incorporated into the matrix to different degrees. The aim of this thesis is to understand the relationship between lipid oxidation and the structural properties of the extrudate and the interaction of lipids with the matrix in order to create a basis for reducing oxidation processes in extrudates. A fractionated lipid extraction was developed, which enabled the characterization and investigation of oxidation processes in different regions of an extrudate. Three fractions were obtained which can be assigned to surface lipids, lipids adsorbing on the inner lamellas of the extrudate and matrix-incorporated lipids. Matrix-incorporated lipids are finely dispersed in the amylose-amylopectin matrix and can only be extracted after an amylase treatment which causes a degradation of the starch matrix. It was shown that the water content of the extrusion mass influences the microstructure and the expansion. The higher the proportion of lipids incorporated in the matrix, the higher is the oxidative stability of the extrudate. Furthermore, the effects of a lipid-based coating on lipid oxidation in extrudates with different microstructures were investigated. Coating with MCT oil inhibited lipid oxidation in corn extrudates beyond the effects of dilution. This effect was particularly pronounced in porous extrudates, as it could be shown that the coating adheres mainly to the surface, migrates only slightly into the core and closes micro cracks. The formation of radicals in model systems and extrudates was investigated by electron paramagnetic resonance spectroscopy. The extrusion process formed stable protein radicals and lipid radical concentration increased simultaneously with the formation of hydroperoxides in the model system. In addition, it was demonstrated that the reaction rate of lipid oxidation is influenced by the matrix. However, the logarithmic plot of the reaction rate, based on the increase of hydroperoxide formation after the lag phase, led to an overestimation of lipid oxidation at room temperature and requires the application of more complex models. Within this thesis, different mechanisms and matrix effects could be identified that influence lipid oxidation during extrusion and storage. They provide a basis for the derivation of factors to increase the oxidative stability of extrudates

On the usability of authentication security communication

Information technology has become more and more ubiquitous in recent times, and it affects almost all aspects of modern life. To protect this technology and its underlying resources, the relevance of computer security has increased as well. However, the past has shown that in many regards, computer security not only depends on secure software and strong cryptography, but is also highly influenced by how humans interact with it. Therefore, usable security and privacy has emerged as a novel research area. It ex- amines how users understand security tooling and measures, and how they interact with them. Furthermore, its main goal is to improve security and related processes to make them easy to understand or use even for novices. In consequence, communication of security risks and potential mitigations is a major factor of usable security. In this thesis, I examine how security is communicated in different areas and between different stakeholders, with the overarching goal of evaluating in which ways communication can be improved, and what consequences a lack of communication can have. In my presented research, I evaluate the usability of authentication measures as a prime example of security measures that are both highly relevant for every type of users, and highly damaging when security is breached. Therefore, I present three peer-reviewed papers in this thesis: In the first, I investigate the setup process of password managers, a tedious task in which users ideally add all passwords at once, while updating them to stronger alternatives. I examine both the onboarding features that password managers provide, and survey end users to inquire how they handled the task of setting up their password managers. In the second work, I examine the communication of multi-factor authentication, especially regarding its recovery after the additional factors become inaccessible. Therefore, I collected authentication and recovery methods mentioned on websites, and conduct a user experience study to gauge whether the described processes are accurate. In the final one, I examine an expert cohort by conducting interviews with open- source contributors, asking them about their individual security measures, such as usage of password managers, and how individual security is communicated to and between contributors. Overall, I find that communication is lacking in various areas: In my research, service providers failed to clearly communicate their policies by either not providing guidance or not updating it, leading to a confusing status quo and insecure decision-making. In other areas, developers preferred to not communicate their security measures and best practices, leading to a volatile environment of unspoken expectations. The results of my research suggest that a more precise and clear communication of both risks and their mitigations can achieve a higher understanding, and in consequence, adoption of security measures. What needs to be communicated or enforced to reach people and increase their authentication security varies, however, with more research and diligence, these challenges can be overcome

Cerebral Small Vessel Disease burden is increased in Systemic Lupus Erythematosus

BACKGROUND AND PURPOSE—: Systemic lupus erythematosus (SLE) increases stroke risk, but the mechanism is uncertain. This study aimed to determine the association between SLE and features on neuroimaging of cerebral small vessel disease (SVD), a risk factor for stroke. METHODS—: Consecutive patients attending a clinic for SLE were recruited. All patients underwent brain magnetic resonance imaging; had blood samples taken for markers of inflammation, endothelial dysfunction, cholesterol, and autoantibodies; and underwent cognitive and psychiatric testing. The data were compared with sex- and age-matched healthy controls and patients with minor stroke. Features of SVD were measured, a total SVD score calculated, and associations sought with vascular risk factors, cognition, SLE activity, and disease duration. RESULTS—: Fifty-one SLE patients (age: 48.8 years; SD: 14.3 years) had a greater total SVD score compared with healthy controls (1 versus 0; P<0.0001) and stroke patients (1 versus 0; P=0.02). There were higher perivascular spaces and deep white matter hyperintensity scores and more superficial brain atrophy in SLE patients versus healthy controls. Despite fewer vascular risk factors than similarly aged stroke patients, SLE patients had similar or more of some SVD features. The total SVD score was not associated with SLE activity, cognition, disease duration, or any blood measure. CONCLUSIONS—: In this data set, SLE patients had a high burden of SVD features on magnetic resonance imaging, particularly perivascular spaces. A larger longitudinal study is warranted to determine the causes of SVD features in SLE and clinical implications