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The Comparison of the Photocatalytic Performance Shown by TiO <sub/>2</sub> and TiO <sub/>2</sub> /WO <sub/>3</sub> Composites— A Parametric and Kinetic Study
摘要: Kinetic and mechanistic related approaches for mostly titania were intensively studied in the literature. However, combined modelling and kinetic studies are few. Therefore, the present work focuses on modelling the dependence of the degradation kinetics of two model compounds (salicylic acid—SA and methyl orange—MO) on Evonik Aeroxide P25, hydrothermally prepared hierarchical TiO2 and P25/WO3 nanostars, obtained also by hydrothermal crystallization. The obtained individual semiconductors and the composites were characterized using XRD, DRS, SEM, while the photocatalytic degradation of the model pollutants were carried out varying the catalyst load, the initial pollutant concentration and incident light intensity. It was found that the degradation kinetics were independent from the hierarchical nature of the material, while significant dependencies of the degradation efficiency was found from the previously mentioned investigation parameters. All these parametric interdependences were successfully studied and a kinetic model was proposed for both bare TiO2 and TiO2/WO3 composite systems.
关键词: Degradation,Salicylic Acid,Methyl Orange,Kinetic Modelling,Composite Materials
更新于2025-09-23 15:22:29
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A unified framework for plasma data modelling in dynamic Positron Emission Tomography studies
摘要: Objective: Full quantification of dynamic PET data requires the knowledge of tracer concentration in the arterial plasma. However, its accurate measurement is challenging due to the presence of radiolabeled metabolites and measurement noise. Mathematical models are fitted to the plasma data for both radiometabolite correction and data denoising. However, the models used are generally not physiologically informed and not consistently applied across studies even when quantifying the kinetics of the same radiotracer, introducing methodological variability affecting the results interpretation. The aim of this study was to develop and validate a unified framework for the arterial data modelling to achieve an accurate and fully-automated description of the plasma tracer kinetics. Methods: The proposed pipeline employs basis pursuit techniques for estimating both radiometabolites and parent concentration models from the raw plasma measurements, allowing the resulting algorithm to be both robust and flexible to the different quality of data available. The pipeline was tested on four PET tracers ([11C]PBR28, [11C]MePPEP, [11C]WAY-100635 and [11C]PIB) with continuous and discrete blood sampling. Results: Compared to the standard procedure, the pipeline provided similar fit of the parent fraction but yielded a better description of the total plasma radioactivity, which in turn allowed a more accurate fit of the tissue PET data. Conclusion: The new method showed superior fits compared to the standard pipeline, for both continuous and discrete arterial sampling protocol, yielding to better description of PET data. Significance: The proposed pipeline has the potential to standardize the blood data modeling in dynamic PET studies given its robustness, flexibility and easiness of use.
关键词: Kinetic modelling,Positron Emission Tomography,Input function,Receptor imaging
更新于2025-09-23 15:22:29
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Kinetic Modelling of Transient Photoluminescence from Thermally Activated Delayed Fluorescence
摘要: A simplified state model and associated rate equations are used to extract the reverse intersystem crossing and other key rate constants from transient photoluminescence measurements of two high performance thermally activated delayed fluorescence materials. The values of the reverse intersystem crossing rate constant are in close agreement with established methods, but do not require a priori assumption of exponential decay kinetics, nor any additional steady state measurements. The model is also applied to measurements at different temperatures and found to reproduce previously reported thermal activation energies for the thermally activated delayed fluorescence process. Transient absorption measurements provide independent confirmation that triplet decay channels (neglected here) have no adverse effect on the fitting.
关键词: Thermally Activated Delayed Fluorescence,Transient Photoluminescence,Reverse Intersystem Crossing,Kinetic Modelling
更新于2025-09-10 09:29:36