369 research outputs found

    Household energy conservation with reality-enhanced serious games: Studies on effects in the real-world

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    In a reality-enhanced game player’s real-world activities, such as household energy saving activities, are integrated in the gameplay of a digital serious game. Players are then immersed in real-life situations that are generated by user interaction with the game, which stimulates the transfer of information between the game world and the real-world. This thesis presents empirical tests of principles that enhance the instructional design of reality-enhanced games to influence household energy conservation. For this research Powersaver Game is designed. We followed a user-centered game design methodology including two design-phases. In design-phase-1, principles are formulated to design a game prototype, and in design-phase-2 potential users evaluate this prototype. We conducted two studies. In a pretest-posttest design, both studies tested whether change in involved engagement, knowledge, attitude and behavior with respect to energy conservation in the household was different for participants playing Powersaver Game compared to a control condition (energy conservation dashboard or a basic version of the game). Families played Powersaver Game for more than three weeks (long-term duration) in their own household. Every day energy saving missions were provided by the game. The main goal was to reduce energy consumption. A real-time connection between the household energy meter and game server was accomplished. In the first study, effects were examined with respect to energy conservation in the household of the energy conservation game compared to an energy conservation dashboard. The form, timing and content of the information that the control condition receives from the energy conservation dashboard are as similar as possible as in the game condition, but excluded game elements. Our energy conservation game is effective in learning people to save energy in the household and to actually do that for the long term, while the energy dashboard does not change that behavior at all. In the second study, effects were examined of the game including the feature competition compared to a basic version of the game. We conclude that competition contributes to more change in energy saving behavior in the long term, and that higher awareness (more accessible knowledge) for a longer period leads to attitude change, which in turn results in behavior change in the long term; particularly the macro-attitude plays here a significant role. In general, we conclude that a digital energy conservation game with real energy conservation activities by monitoring real-life household energy consumption, which is developed in a thoughtful, iterative user-centered design process, significantly reduces energy consumption in the long term (in the weeks immediately following the intervention). In addition, the game feature competition contributes to even more change in energy conservation. Knowledge about saving energy at home increased, and engagement remained high during the whole intervention. In contrast, attitude change did not take place because it was already high from the beginning. Gamification by applying reality-enhanced games is still an emerging principle in research. It has a great potential for behavior change and attitude change in novel and engaging ways, and our results can be used in the development of effective games

    Review of Serious Energy Games : Objectives, Approaches, Applications, Data Integration, and Performance Assessment

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    In recent years, serious energy games (SEGs) garnered increasing attention as an innovative and effective approach to tackling energy-related challenges. This review delves into the multifaceted landscape of SEG, specifically focusing on their wide-ranging applications in various contexts. The study investigates potential enhancements in user engagement achieved through integrating social connections, personalization, and data integration. Among the main challenges identified, previous studies overlooked the full potential of serious games in addressing emerging needs in energy systems, opting for oversimplified approaches. Further, these studies exhibit limited scalability and constrained generalizability, which poses challenges in applying their findings to larger energy systems and diverse scenarios. By incorporating lessons learned from prior experiences, this review aims to propel the development of SEG toward more innovative and impactful directions. It is firmly believed that positive behavior changes among individuals can be effectively encouraged by using SEG

    Plasmin-cleaved von Willebrand factor as a biomarker for microvascular thrombosis

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    von Willebrand factor (VWF) is an essential contributor to microvascular thrombosis. Physiological cleavage by ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13) limits its prothrombotic properties, explaining why ADAMTS13 deficiency leads to attacks of microthrombosis in patients with thrombotic thrombocytopenic purpura (TTP). We previously reported that plasminogen activation takes place during TTP attacks in these patients. Furthermore, stimulation of plasminogen activation attenuates pathogenesis in preclinical TTP models in vivo. This suggests that plasmin is an endogenous regulator of VWF thrombogenicity, in particular when ADAMTS13 falls short to prevent microvascular occlusions. VWF cleavage by plasmin is biochemically distinct from cleavage by ADAMTS13. We hypothesized that plasmin-cleaved VWF (cVWF) holds value as a biomarker of microvascular thrombosis. Here, we describe the development of a variable domain of heavy-chain-only antibody (VHH)-based bioassay that can distinguish cVWF from intact and ADAMTS13-cleaved VWF in plasma. We validate this assay by tracking cVWF release during degradation of microthombi in vitro. We demonstrate that endogenous cVWF formation takes place in patients with TTP during acute attacks of thrombotic microangiopathy but not in those in remission. Finally, we show that therapeutic plasminogen activation in a mouse model of TTP amplifies cVWF formation, which is accompanied by VWF clearance. Our combined findings indicate that cVWF is released from microthrombi in the context of microvascular occlusion

    Platelets of patients with chronic kidney disease demonstrate deficient platelet reactivity in vitro

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    <p>Abstract</p> <p>Background</p> <p>In patients with chronic kidney disease studies focusing on platelet function and properties often are non-conclusive whereas only few studies use functional platelet tests. In this study we evaluated a recently developed functional flow cytometry based assay for the analysis of platelet function in chronic kidney disease.</p> <p>Methods</p> <p>Platelet reactivity was measured using flow cytometric analysis. Platelets in whole blood were triggered with different concentrations of agonists (TRAP, ADP, CRP). Platelet activation was quantified with staining for P-selectin, measuring the mean fluorescence intensity. Area under the curve and the concentration of half-maximal response were determined.</p> <p>Results</p> <p>We studied 23 patients with chronic kidney disease (9 patients with cardiorenal failure and 14 patients with end stage renal disease) and 19 healthy controls. Expression of P-selectin on the platelet surface measured as mean fluorescence intensity was significantly less in chronic kidney disease patients compared to controls after maximal stimulation with TRAP (9.7 (7.9-10.8) vs. 11.4 (9.2-12.2), P = 0.032), ADP (1.6 (1.2-2.1) vs. 2.6 (1.9-3.5), P = 0.002) and CRP (9.2 (8.5-10.8) vs. 11.5 (9.5-12.9), P = 0.004). Also the area under the curve was significantly different. There was no significant difference in half-maximal response between both groups.</p> <p>Conclusion</p> <p>In this study we found that patients with chronic kidney disease show reduced platelet reactivity in response of ADP, TRAP and CRP compared to controls. These results contribute to our understanding of the aberrant platelet function observed in patients with chronic kidney disease and emphasize the significance of using functional whole blood platelet activation assays.</p

    Generation of anti-idiotypic antibodies to detect anti-spacer antibody idiotopes in acute thrombotic thrombocytopenic purpura patients

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    In autoantibody-mediated autoimmune diseases, autoantibody profiling allows to stratify patients and link autoantibodies with disease severity and outcome. However, in immune-mediated thrombotic thrombocytopenic purpura patients, stratification according to antibody profiles and their clinical relevance has not been fully explored. We aimed at developing a new type of autoantibody profiling assay for immune-mediated thrombotic thrombocytopenic purpura based on the use of anti-idiotypic antibodies. Anti-idiotypic antibodies against 3 anti-spacer autoantibodies were generated in mice and were used to capture the respective anti-spacer idiotopes from 151 acute immune-mediated thrombotic thrombocytopenic purpura plasma samples. We next deciphered these anti-spacer idiotope profiles in immune-mediated thrombotic thrombocytopenic purpura patients and investigated if these limited idiotope profiles could be linked with disease severity. We developed 3 anti-idiotypic antibodies that recognized particular idiotopes in the anti-spacer autoantibodies II-1, TTP73 or I-9, that are involved in ADAMTS13 binding. Thirty-five, 24 and 42% of patients were positive for antibodies with the II-1, TTP73 and I-9 idiotopes, respectively. Stratifying patients according to the corresponding 8 anti-spacer idiotope profiles revealed an until now unknown insight into the anti-spacer II-1, TTP73 and I-9 idiotope profiles in these patients. Finally, these limited idiotope profiles showed no association with disease severity. We successfully developed 3 anti-idiotypic antibodies that allowed us to determine the profiles of the anti-spacer II-1, TTP73 and I-9 idiotopes in immune-mediated thrombotic thrombocytopenic purpura patients. Increasing the number of patients and/or future development of additional anti-idiotypic antibodies against other anti-ADAMTS13 autoantibodies might allow to identify idiotope profiles of clinical, prognostic value

    Predictors of bleeding complications during catHeter-dirEcted thrombolysis for peripheral arterial occlusions (POCHET)

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    Introduction The risk of major bleeding complications in catheter directed thrombolysis (CDT) for acute limb ischemia (ALI) remains high, with reported major bleeding complication rates in up to 1 in every 10 treated patients. Fibrinogen was the only predictive marker used for bleeding complications in CDT, despite the lack of high quality evidence to support this. Therefore, recent international guidelines recommend against the use of fibrinogen during CDT. However, no alternative biomarkers exist to effectively predict CDT-related bleeding complications. The aim of the POCHET biobank is to prospectively assess the rate and etiology of bleeding complications during CDT and to provide a biobank of blood samples to investigate potential novel biomarkers to predict bleeding complications during CDT. Methods The POCHET biobank is a multicentre prospective biobank. After informed consent, all consecutive patients with lower extremity ALI eligible for CDT are included. All patients are treated according to a predefined standard operating procedure which is aligned in all participating centres. Baseline and follow-up data are collected. Prior to CDT and subsequently every six hours, venous blood samples are obtained and stored in the biobank for future analyses. The primary outcome is the occurrence of non-access related major bleeding complications, which is assessed by an independent adjudication committee. Secondary outcomes are non-major bleeding complications and other CDT related complications. Proposed biomarkers to be investigated include fibrinogen, to end the debate on its usefulness, anti-plasmin and D-Dimer. Discussion and conclusion The POCHET biobank provides contemporary data and outcomes of patients during CDT for ALI, coupled with their blood samples taken prior and during CDT. Thereby, the POCHET biobank is a real world monitor on biomarkers during CDT, supporting a broad spectrum of future research for the identification of patients at high risk for bleeding complications during CDT and to identify new biomarkers to enhance safety in CDT treatment

    Severe Dengue Is Associated with Consumption of von Willebrand Factor and Its Cleaving Enzyme ADAMTS-13

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    Severe dengue infections are characterized by thrombocytopenia, clinical bleeding and plasma leakage. Activation of the endothelium, the inner lining of blood vessels, leads to the secretion of storage granules called Weibel Palade bodies (WPBs). We demonstrated that severe dengue in Indonesian children is associated with a strong increase in plasma levels of the WPB constituents von Willebrand factor (VWF), VWF propeptide and osteoprotegerin (OPG). An increased amount of the hemostatic protein VWF was in a hyperreactive, platelet binding conformation, and this was most pronounced in the children who died. VWF levels at enrollment were lower than expected from concurrent VWF propeptide and OPG levels and VWF levels did not correlate well with markers of disease severity. Together, this suggests that VWF is being consumed during severe dengue. Circulating levels of the VWF-cleaving enzyme ADAMTS-13 were reduced. VWF is a multimeric protein and a subset of children had a decrease in large and intermediate VWF multimers at discharge. In conclusion, severe dengue is associated with exocytosis of WPBs with consumption of VWF and low ADAMTS-13 activity levels. This may contribute to the thrombocytopenia and complications of dengue
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