Julkaisuarkisto

Four αI domain-containing integrins (α1β1, α2β1, α10β1, and α11β1) have evolved to recognize various members of the collagen family. A defining structural feature of these receptors is the presence of the αC helix within their αI domains (Glu284–Arg288 in the α2I domain), a structure solely found in collagen-binding integrins, whose functional mechanism has remained unclear. To elucidate the functional role of the αC helix, and to assess the contribution of the mechanistically important Arg288-Glu318 ion pair in α2I domain activation, we created two variants α2IR288A and α2IE318A. Functional solid-phase binding assays and surface plasmon resonance revealed that these variants exhibit strikingly increased avidity for collagens I and IV, whereas affinities for triple-helical GFOGER peptides, representing a single binding motif, were only slightly increased. The variants displayed distinct ligand-binding profiles, including differences in association and dissociation constants. To understand these differences at a structural level, we determined four novel X-ray crystal structures of the variants, including both ligand-free and ligand-bound (succinic acid or malic acid) states. These structures revealed differences in the folding of the αC helix region, suggesting that its conformation regulates α2I domain activation and ligand specificity, consistent with our binding assays. Additionally, the structures captured the movements of the catalytic metal ion in the metal ion dependent adhesion site, providing a detailed view of the sophisticated activation mechanism of the α2I domain.

This paper presents a longitudinal ethical analysis of Untappd, a social drinking application that gamifies beer consumption through badges, streaks, and social sharing. Building on an exploratory study conducted in 2020, we revisit the platform in 2025 to examine how its gamification features and ethical framings have evolved. Drawing on traditional ethical theory and practical frameworks for Software Engineering, we analyze five categories of badges and their implications for user autonomy and well-being. Our findings show that, despite small adjustments and superficial disclaimers, many of the original ethical issues remain. We argue for continuous ethical reflection built embedded into software lifecycles to prevent the normalization of risky behaviors through design.

Photovoltaic (PV) production grows rapidly in the Nordics, but literature on calculating long-term PV performance losses remains limited in these conditions, leading to inaccurate yield estimations and economic losses. To fill this knowledge gap, this contribution (1) shows typical PV performance characteristics, (2) obtains performance loss rates (PLRs) from multiple systems, and (3) assesses the best practices of PLR calculation under these conditions. For these objectives, we compared various methods for all steps of PLR calculation, including data filters, performance metrics, aggregation intervals, and statistical models for five systems (with 2.5–6 years of data) across Finland, from 60° to 67° N. Dark winters and snow coverage caused gaps and anomalies to the performance time series during wintertime, resulting in unrealistic PLRs. Excluding these anomalies with performance threshold filter improved the results. As the different methods can drastically affect the PLR value, an ensemble method consisting of an assessment of average PLR with over 700 calculation approaches was validated to be essential in identifying robust PLRs. Using this ensemble method, the system PLR estimates ranged from −−0.41%/year to −−2.65%/year. The data and codes are made publicly available, contributing to open access of PV datasets and allowing wider application of the PLR methodology.