Challenges in Using mHealth Data From Smartphones and Wearable Devices to Predict Depression Symptom Severity: Retrospective Analysis

A number of challenges exist for the analysis of mHealth data: maintaining participant engagement over extended time periods and therefore understanding what constitutes an acceptable threshold of missing data; distinguishing between the cross-sectional and longitudinal relationships for different features to determine their utility in tracking within-individual longitudinal variation or screening individuals at high risk; and understanding the heterogeneity with which depression manifests itself in behavioral patterns quantified by the passive features. From 479 participants with MDD, we extracted 21 features capturing mobility, sleep, and smartphone use. We investigated the impact of the number of days of available data on feature quality using the intraclass correlation coefficient and Bland-Altman analysis. We then examined the nature of the correlation between the 8-item Patient Health Questionnaire (PHQ-8) depression scale (measured every 14 days) and the features using the individual-mean correlation, repeated measures correlation, and linear mixed effects model. Furthermore, we stratified the participants based on their behavioral difference, quantified by the features, between periods of high (depression) and low (no depression) PHQ-8 scores using the Gaussian mixture model. We demonstrated that at least 8 (range 2-12) days were needed for reliable calculation of most of the features in the 14-day time window. We observed that features such as sleep onset time correlated better with PHQ-8 scores cross-sectionally than longitudinally, whereas features such as wakefulness after sleep onset correlated well with PHQ-8 longitudinally but worse cross-sectionally. Finally, we found that participants could be separated into 3 distinct clusters according to their behavioral difference between periods of depression and periods of no depression

Remote assessment of disease and relapse in major depressive disorder (RADAR-MDD): recruitment, retention, and data availability in a longitudinal remote measurement study

BACKGROUND: Major Depressive Disorder (MDD) is prevalent, often chronic, and requires ongoing monitoring of symptoms to track response to treatment and identify early indicators of relapse. Remote Measurement Technologies (RMT) provide an opportunity to transform the measurement and management of MDD, via data collected from inbuilt smartphone sensors and wearable devices alongside app-based questionnaires and tasks. A key question for the field is the extent to which participants can adhere to research protocols and the completeness of data collected. We aimed to describe drop out and data completeness in a naturalistic multimodal longitudinal RMT study, in people with a history of recurrent MDD. We further aimed to determine whether those experiencing a depressive relapse at baseline contributed less complete data. METHODS: Remote Assessment of Disease and Relapse – Major Depressive Disorder (RADAR-MDD) is a multi-centre, prospective observational cohort study conducted as part of the Remote Assessment of Disease and Relapse – Central Nervous System (RADAR-CNS) program. People with a history of MDD were provided with a wrist-worn wearable device, and smartphone apps designed to: a) collect data from smartphone sensors; and b) deliver questionnaires, speech tasks, and cognitive assessments. Participants were followed-up for a minimum of 11 months and maximum of 24 months. RESULTS: Individuals with a history of MDD (n = 623) were enrolled in the study,. We report 80% completion rates for primary outcome assessments across all follow-up timepoints. 79.8% of people participated for the maximum amount of time available and 20.2% withdrew prematurely. We found no evidence of an association between the severity of depression symptoms at baseline and the availability of data. In total, 110 participants had > 50% data available across all data types. CONCLUSIONS: RADAR-MDD is the largest multimodal RMT study in the field of mental health. Here, we have shown that collecting RMT data from a clinical population is feasible. We found comparable levels of data availability in active and passive forms of data collection, demonstrating that both are feasible in this patient group. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12888-022-03753-1

HIGH-TC-SUPERCONDUCTORS PREPARED BY CVD

YBa2Cu3O7-δ - deposition experiments were carried out in a cold wall stagnation flow CVD-reactor on single crystalline (100)-oriented SrTiO3-substrates at a total pressure of 10 mbar. As source materials different β-diketonate derivates of yttrium, barium and copper were investigated concerning their volatility and decomposition behaviour. Finally for the YBa2Cu3O7-δ deposition process Y(thd)3, Ba(thd)2 and Cu(thd)2 were used. The evaporation temperatures Tv were 112, 208 and 117 °C respectively. High quality films can be obtained with the c-axis perdendicular to the substrate surface at temperatures higher than 850 °C. The transition temperatures of the coatings are higher than 90 K and the critical current densities are in the order of jc = 106 A/cm2 at 77 K and self magnetic field

THE Ba-PROBLEM IN CVD-YBa2 Cu3 O7-[MATH] HTC SUPERCONDUCTORS

The evaporation behaviour of Ba(thd)2 in a CVD-process for HTc-Superconductors is presented. The long-time stability as well as possibilities to increase the evaporation rates by changing the geometry of the evaporator and the process conditions are discussed

Plasmatechnische Untersuchung zur Realisierung einer inkohaerenten Hochleistungs-UV-Strahlungsquelle Teilprojekt C: Verfahrenstechnische Untersuchungen zur Realisierung von UV-Hochleistungsstrahlern. Abschlussbericht 1991-1993

New powerful UV sources can have a drastic impact on the growing UV-market. Within this subproject C various engineering solutions towards the realization of high-power radiation sources (excimer-UV-lamps) were investigated. Starting from the state of the art (section A, B) new concepts for excimer-UV-equipment (e.g. large area or internal radiators) which could be transferred directly to industrial plants (sections C - G) were developed. In addition, emphasis was put on the application of these excimer UV lamps in areas, such as surface metallization, modification of polymer surfaces, and UV-induced decomposition of hazardous materials. Also, a brief discussion regarding the evaluation and marketability of the excimer-UV technology was included. (orig.)SIGLEAvailable from TIB Hannover: F94B1445+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany)DEGerman