Sclerostin is a protein secreted by osteocytes whose encoding gene SOST is regulated by mechanical stimuli, cytokines, and all-trans retinoic acid (ATRA) and mediates antianabolic effects on bone formation as an inhibitor of the canonical Wnt/β-catenin pathway. Interestingly, skeletal muscle has recently been identified as another source of sclerostin, suggesting that the musculature may play an important role in maintaining bone mass. However, regulators of muscular SOST expression are virtually unknown. This study investigates the influence of ATRA and the provitamin A derivative beta-carotene (β-C) on sclerostin synthesis in muscle cells. The impact of ATRA, its synthetic analog TTNPB, and β-C on Sost transcription was analyzed by qRT-PCR in C2C12 myotubes and the secreted sclerostin protein by ELISA. ATRA strongly increases the sclerostin synthesis in C2C12 myotubes in a dose-dependent manner. The stimulating effect of ATRA and TTNPB on Sost is largely reduced in the presence of the retinoic acid receptor inhibitor AGN193109. β-C also increases the Sost expression, but this effect vanishes when β-C is coincubated with beta-carotene 15,15′-monooxygenase 1 (BCMO1)-specific siRNA. Thus, ATRA is a potent stimulator of sclerostin release in muscle cells. β-C can also increase Sost mRNA abundance, but this effect depends on the conversion to a retinoid.

Background: Augmented reality (AR)-based systems offer novel opportunities for digital support in physiotherapy and rehabilitation. This is especially relevant in the context of an aging population and the growing shortage of healthcare professionals. Methods: This study employed a user-centered design with iterative prototype refinement and investigated the perceived usability and user acceptance of a prototype AR-based sports therapy system (“STAR”), developed within an ongoing interdisciplinary research project, from the perspectives of patients and healthcare professionals across one iteration cycle. After an initial needs analysis (T0), participants interacted in an observer role with the system at two time points (T1, T2) using an AR headset (Microsoft HoloLens 2). They did not perform exercises but only interacted with the application by navigating through the system and viewing the exercise demonstrations. Between T1 and T2, a tutorial was integrated, exercise animations and voiceovers were revised, and voiceover controls and navigation were optimized. Usability was measured using the System Usability Scale (SUS), and user acceptance via the Technology Usage Inventory (TUI). Results: A total of 15 participants (10 patients and 5 therapists) completed both testing sessions. The average SUS score across both patients and therapists improved from 54.5 (SD = 18.8) to 71.2 (SD = 13.1), reflecting a statistically significant increase in perceived usability (p < 0.001). The usability rating improved from “ok” to “good” according to the SUS interpretation scale. The TUI subscales skepticism, immersion, accessibility and usability improved significantly, while interest, usefulness and intention-to-use only showed trend-level changes. Conclusions: The findings suggest that a user-centered development process can enhance the perceived usability and user acceptance of AR- based virtual care tools during the prototype stage by providing early-stage empirical evidence linking specific user-centered design interventions to changes in Technology Acceptance Model-related acceptance constructs.

This study builds on initial ADApp research that identified the factors that influence the intention to use a pharmacy drone app for urgent medication delivery. While previous studies and theories have predominantly focused on user acceptance alone, the present qualitative study introduced a holistic model that integrates user acceptance theories as well as user-centered design principles and technology features. It focused on the user journey to derive core statements from the development of a drone-based application using a qualitative theory synthesis approach (study 1), and explored the perceived participatory collaboration between developers (software and drone developers) and co-developers (core group participants) using final tandem discussions and a qualitative content analysis method (study 2). Study 1 resulted in the identification of eight categories that serve as technical working goals for future participatory technology development. Study 2 identified five critical factors that provide insight into the unique challenges and goals of collaborative development. Both studies contribute to a better understanding of the essential factors that lead to successful participatory processes between developers and co-developers aimed at increasing usability and intention to use. Based on these findings, an integrated model is presented to support participatory design strategies in healthcare technology development.

Augmented reality (AR)-based systems offer novel opportunities for digital support in physiotherapy and rehabilitation. This is especially relevant in the context of an aging population and the growing shortage of healthcare professionals. This study employed a user-centered design with iterative prototype refinement and investigated the perceived usability and user acceptance of a prototype AR-based exercise therapy system (“STAR”) from the perspectives of patients and healthcare professionals across one iteration cycle. Participants interacted with the system at two time points (T1, T2) using an AR headset. Usability was measured using the System Usability Scale (SUS), user acceptance via the Technology Usage Inventory (TUI). A total of 15 participants (10 patients, 5 therapists) completed both testing sessions. The average SUS score improved from 54.5 (SD = 17.2) to 71.2 (SD = 16.1), reflecting a small but statistically significant increase in perceived usability (p < .001). The usability rating improved from “ok” to “good” according to the established SUS interpretation scale. On average there were improvements in scores for all scales of the TUI questionnaire. The findings suggest that a user-centered development process can substantially enhance the perceived usability of AR systems, particularly among target populations with limited prior exposure to digital technologies.

Independent mobility is crucial for social participation and quality of life in later life, especially in rural areas where public transport is limited. Light electric vehicles (LEVs) may offer a promisingalternativefor everyday mobility; however, it remains unclear which features and contextual conditions are necessary for their usability and acceptance among older adults in their rural settings. As an initial exploratory step within the LeiFlex project, this mixed-methods design study aimed to assess feasibility and generate preliminary insights for further development. A user-centred study was conducted with 20 participants (≥ 60 years) in rural Saxony-Anhalt, Germany. Participants completed supervised test drives with a commercially available LEV, followed by standardized usability and acceptance questionnaires (System Usability Scale, Technology Usage Inventory) and semi-structured focusgroup discussions. Qualitative data were analysed using content analysis and complemented by descriptive quantitative results. Overall, attitudes towards LEVs were positive, although usability was rated as marginal (SUS _mean = 53.0). Key requirements included intuitive braking logic, clear visual and acoustic feedback in safety-critical situations, ergonomic adjustability, and perceived safety. Gender differences were observed. Women reported lower usability and were more sceptical, despite having a similar intention to use. The findings suggest that acceptance of LEVs among older adults is shaped not only by modifiable usability and design characteristics, but also the conditions in which these vehicles are used. These preliminary results highlight the need for flexible, modular, and age-appropriate LEV concepts and provide a basis for further investigation in larger and more comprehensive studies.