We wished to establish a reproducible model for fracture fixation to be used in fracture healing research and therefore developed an external fixation construct and surgical procedure adapted to SpragueDawley rats. We evaluated the mechanical properties of the construct in brass rods and rat bone, in an Instron test machine with axial and transverse loading, and the in vivo performance. We found that the mechanical properties of the construct in brass rods were predictable and could be repeated in rat femora. In all tests, the axial load was about 10 times the transverse for the same degree of deformation. The stiffness among fixators was uniform. 1 mm pins caused about 50% less stiffness than 1.2 mm pins in axial loading of rat bone (p < 0.001) and brass rods (p < 0.001) as well as in transverse loading of brass rods (p < 0.001). Loosening of 1 or 2 screws that lock the pins to the fixator reduced stiffness by about 50% in axial loading of rat bone (p = 0.009) and brass rods (p = 0.05). A change in the distance between the bone surface and the fixator was linearly related to the stiffness in axial loading of rat bone (p < 0.001) and brass rods (p < 0.001) and in transverse loading of brass rods (p < 0.001). If the bone ends touched each other, the axial stiffness of the construct increased almost 10 times (265 N/mm), as compared to a fracture gap size of 2 mm (31 N/mm). In vivo experiments had a complication rate of less than 10% when we used 1.2 mm pins, 6 mm offset and rats weighing 350-450 g.Our method and device for experimental external fixation of rat femora are reliable and the findings are reproducible. These can be used in bone repair and fracture healing research.

Problem gambling creates significant harm for the gambler and for concerned significant others (CSOs). While several studies have investigated the effects of individual cognitive behavioral therapy (CBT) for problem gambling, less is known about the effects of involving CSOs in treatment. Behavioral couples therapy (BCT) has shown promising results when working with substance use disorders by involving both the user and a CSO. This pilot study investigated BCT for problem gambling, as well as the feasibility of performing a larger scale randomized controlled trial. 36 participants, 18 gamblers and 18 CSOs, were randomized to either BCT or individual CBT for the gambler. Both interventions were Internet-delivered self-help interventions with therapist support. Both groups of gamblers improved on all outcome measures, but there were no differences between the groups. The CSOs in the BCT group lowered their scores on anxiety and depression more than the CSOs of those randomized to the individual CBT group did. The implications of the results and the feasibility of the trial are discussed.

Background and aims: The COVID-19 pandemic has dramatically changed life circumstances for adolescents worldwide. With schools being closed and regular activities being cancelled, gaming and social media use are activities that might gain in importance. There is a risk that these online behaviours have negative effects on other important activities, such as being physically active, sleeping, and studying, as well as general well-being. The aim of this study was to investigate the effects of the COVID-19 pandemic on gaming and social media use, and its effects on the well-being of adolescents. Methods: A total of 1232 adolescents (82.5% female) participated in an anonymous web survey containing questions on gaming, social media use, and perceived negative consequences of gaming and social media use during the COVID-19 pandemic. The results were analysed with a quasi-Poisson regression model. Results: The results indicated an increase in gaming and social media use, which was associated with negative consequences and perceived well-being. A majority of adolescents reported that they used social media more than they felt comfortable with. There were large differences between boys and girls, with girls being more negatively affected across measures. Discussion: The increase in gaming and social media use during the COVID-19 pandemic might have negative effects on the well-being of adolescents, and on other activities that are important to health. Our interpretation of the findings is that gaming and social media use might partly function as coping mechanisms to deal with stress and/or boredom resulting from COVID-19 restrictions. There is a risk that these coping strategies become maladaptive over time. Conclusions: The restrictions from the COVID-19 pandemic have resulted in an increase in the amount of time adolescents spend gaming and on social media, which might have negative effects on their well-being. This study highlights the urgent need to consider adaptive and healthy coping strategies for adolescents given the pandemic may mean that daily living could continue to be altered in the near future.

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