BackgroundIn the past decade, the use of technologies to persuade, motivate, and activate individuals’ health behavior change has been a quickly expanding field of research. The use of the Web for delivering interventions has been especially relevant. Current research tends to reveal little about the persuasive features and mechanisms embedded in Web-based interventions targeting health behavior change. ObjectivesThe purpose of this systematic review was to extract and analyze persuasive system features in Web-based interventions for substance use by applying the persuasive systems design (PSD) model. In more detail, the main objective was to provide an overview of the persuasive features within current Web-based interventions for substance use. MethodsWe conducted electronic literature searches in various databases to identify randomized controlled trials of Web-based interventions for substance use published January 1, 2004, through December 31, 2009, in English. We extracted and analyzed persuasive system features of the included Web-based interventions using interpretive categorization. ResultsThe primary task support components were utilized and reported relatively widely in the reviewed studies. Reduction, self-monitoring, simulation, and personalization seem to be the most used features to support accomplishing user’s primary task. This is an encouraging finding since reduction and self-monitoring can be considered key elements for supporting users to carry out their primary tasks. The utilization of tailoring was at a surprisingly low level. The lack of tailoring may imply that the interventions are targeted for too broad an audience. Leveraging reminders was the most common way to enhance the user-system dialogue. Credibility issues are crucial in website engagement as users will bind with sites they perceive credible and navigate away from those they do not find credible. Based on the textual descriptions of the interventions, we cautiously suggest that most of them were credible. The prevalence of social support in the reviewed interventions was encouraging.ConclusionsUnderstanding the persuasive elements of systems supporting behavior change is important. This may help users to engage and keep motivated in their endeavors. Further research is needed to increase our understanding of how and under what conditions specific persuasive features (either in isolation or collectively) lead to positive health outcomes in Web-based health behavior change interventions across diverse health contexts and populations.

This study presents the results of an aging stability study of complete blood count (CBC) and leukocyte differential parameters using the Abbott CELL-DYN Sapphire hematology analyzer. Stability studies showed no substantial change in CBC parameters up to 24-48 h at +23 +/- 2 degrees C (room temperature), except for optical platelet count (PLTo). For specimens aged over 24, the value of impedance platelet count yielded more reliable results than the routine PLTo. White blood cell (WBC) differential parameters, except eosinophils, were stable for up to 48 h at +23 +/- 2 degrees C. CBC parameters were stable for 72 h, except mean platelet volume, which slightly increased between 48 and 72 h, at +4 degrees C. WBC differentials were stable 48-72 h, with a slight decrease observed in absolute neutrophils and lymphocytes at +4 degrees C.

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