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As a first step in the development of real-time stress monitoring during foal training, modelling techniques are used to obtain off-line stress monitoring. Based on the model parameters of dynamic autoregressive models of the foal’s HR, features are calculated and used to monitor stress. Some of the features enable the monitoring of stress, while others can be used to detect high levels of stress. One of the features defined in this research is able to detect high stress levels with on average an accuracy of almost 70 %. The HR measurements are also used to calculate HR measures that can be used to evaluate the progress of the foals in their training program. In a training session, the easily calculated median, mean and minimum (min) HR were good representatives for the mean stress level of the foals during the training. Based on the mean HR, it is observed that – in an ideal training program – the foals experience significantly (p = 0.00330) less stress at the end of the initial training program with respect to the first training session, which is confirmed by the behaviour-based gold standard stress levels. The progress of the foal in the program, involving the decrease of the mean stress level, is observed when taking into account the full training, but also for every respective part of the training: HEADSTALL ON (p = 0.00764), ROPE ON (p = 0.00260), LIFTING LEGS (p = 0.00180), TOURS (p = 0.00190), ROPE OFF (p = 0.02830), HEADSTALL OFF (p = 0.02160) and TOUCH HEAD (p = 0.01789). The occurrence and intensity of short moments of high stress levels are represented by the maximum (max) HR and were found to be also significantly (p = 0.02341) lower in the last initial training session with respect to the first. Also, the dynamic range of the HR, represented by the standard deviation (std) of the measured HRs, decreases throughout the training program, with already in the sixth training session a significant (p = 0.04525) decrease with respect to the first training. Meanwhile, it is interesting to evaluate the stress within a training session. In the beginning of a training session when the headstall is put on, stress is induced and only decreases again significantly (p = 0.00030 for stress level 1 and p = 0.01350 for level 3) once the headstall is taken off again, which indicates the end of the training. Based on the mean HR, the significant (p = 0.04640) higher stress level in the beginning, in this case when the rope is put on, and the end of the training session when the rope is taken off again, is also observed. Thus, based on HR measurements, the stress levels of the foals can be monitored off-line using dynamic autoregressive models, while the progress of the foals can be evaluated both within a training session and as well as throughout the training program using HR measures.

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When a person shows clinical symptoms, a general practitioner is consulted. To make the correct diagnosis, the practitioner often prescribes one or more diagnostic tests such as a blood test. A blood test is performed in general laboratories, meaning the blood sample is sent to a centralised laboratory, where it is often tested with bulky instruments requiring trained operators. To circumvent this lengthy process, point-of-care (POC) diagnostic tests are being developed, which are diagnostic tests performed near the patient, often as lab-on-chips (LOCs). Such LOCs process small volumes of reagents and samples, by performing operations similar to classical laboratory operations to make a correct diagnosis. To be used as POC devices, these LOCs must be cheap, easy to use and portable. The SIMPLE or "self-powered imbibing microfluidic pump by liquid encapsulation" meets these requirements and is therefore a promising platform in POC diagnostics. The design of the SIMPLE platform still heavily relies on a trial-and-error approach. Therefore, in this thesis, a model was developed to simulate the flow in the paper pumps used in the SIMPLE platform, thus avoiding the trial-and-error method to design the pumps. Afterwards, the model was validated by experiments using the SIMPLE platform. Different shapes and paper types were tested to determine the influence of shape and paper type on the flow. Whatman 40 (W40) filter paper was used to test a narrow, straight strip. Both the model and the experiments showed high variability in this case, which was possibly caused by the structure or a possible compression of the paper. Whatman 598 (W598) filter paper was then tested in a narrow, straight strip and in five fan shapes with different angles, since such fan shapes are often used in the SIMPLE platform. The variability was smaller in this case, but, with the strip, the flow in the experiments was much faster than in the simulation. This difference may have been caused by the testing method, so further experiments are needed to accurately validate the model for a narrow, straight strip. For fan shapes, the experiments and simulations were in better agreement, meaning the model was able to accurately predict the fluid flow in fan shaped W598 paper.

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As society becomes more reliant on the use of plastics, consumption grows every year and waste increases proportionally. Plastics are released in nature, polluting the environment, biological life, and ecosystems. Once discarded, plastics degrade to microplastics (<5 mm) and nanoplastics (<1 µm) due to weathering processes and photodegradation. Micro- and nanoplastics (MNP’s) can enter the human body via several pathways, and induce toxicological effects on human health. Very little is known regarding these adverse effects due to a lack of appropriate detection techniques. Also, localization of particles in biological samples is required to investigate local effects, meaning that the preservation of bio-context is essential to achieve this. Staining of MNP’s with Nile Red (NR), a solvatochromic dye, can serve as a fluorescent labeling technique for MNP’s, enabling high-resolution particle detection and polymer identification. However, since NR has a high affinity for lipophilic carbon structures, organic materials like lipids get co-stained, inducing false-positive results. Furthermore, biological samples often are opaque, limiting laser transmission due to light scattering. Thirdly, autofluorescence causes a lot of background signal, interfering with the signal obtained from small plastics and making detection of MNP’s more challenging. For this reason, optical clearing protocols are needed to resolve these issues by extracting these structures from biological samples. 3D spheroids (co-cultured with MNP’s) and tissue samples were prepared and anchored in an acrylamide gel. This enabled the preservation of bio-context, allowing particle localization in a subsequent stage. Next, optical clearing steps were added and different protocols were compared, starting from a protein digestion step. This resulted in a more effective removal of lipids, which enhanced laser transmission (decrease in scattering) and reduced autofluorescence. This facilitates future research towards MNP-detection with NR staining, as false positive results get ruled out more effectively.

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Micro-aggregates have several unique properties that make them suitable for tissue engineering: they are associated with increased cell viability, they enhance multilineage differentiation and they secrete trophic factors with an anti-inflammatory effect. In addition, micro-aggregates have the ability to fuse into one larger structure when brought into close contact. Hence, they are of great interest in bottom-up tissue engineering, in which large heterotypic tissues that mimic the native organisational tissue structure are gradually built up by using small units as building blocks. An important step for the application of micro-aggregates in tissue engineering is a complete understanding of their formation. During this formation, a change in cell morphology, determined by cell contractility and cortical tension, is required. These factors are both determined by the structure and functionality of the cytoskeleton. Therefore, the importance of different components of the cytoskeleton during the aggregation of hPDCs was studied by adding different inhibitors to the medium. In this thesis, Y-27632, a ROCK-inhibitor, and (S)-nitroblebbistatin, an inhibitor of MYH ATPase, were evaluated for their effect on aggregate formation. Two different aggregate sizes were tested since cell number might influence cell aggregation by affecting contact opportunities between cells and cell survival. The dynamics of the aggregation behaviour were captured using time-lapse microscopy. Area and circularity of the aggregates were extracted from the images and analysed using a data-based modelling approach. It is demonstrated that ROCK-inhibitor reduces compaction and slows down the formation of micro-aggregates compared to control conditions. Moreover, the effect of Y-27632 is found to be depended on aggregate size. Experiments with (S)-nitroblebbistatin were not coherent. Consequently, no conclusions concerning the contribution of myosin II to cellular aggregation could be made. In addition to time-lapse microscopy, aggregates treated with ROCK-inhibitor were imaged in confocal microscopy in order to quantify cell viability and visualise the actin network as well as the nucleus. Although this analysis did not reveal any statistically significant results, some clear trends are observed. First of all, it is stated that cells at the boundary have a higher volume compared to central cells. Secondly, it is seen that boundary cells have a tendency to become more spherical as the concentration of Y-27632 is increased. It is believed that a more complete insight in aggregate formation is the first step towards a better process control and thus would enhance the performance of the final engineered tissue.

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Technology has become indispensable in our daily life and has also found its way into the sports environment where it has proven its benefits. Sensors are implemented for measuring variables such as heart rate, blood pressure, speed and distance covered. One equally important but often forgotten variable in elite sport is the mental load of an athlete. Top performances cannot be reached when psychological aspects are unfavourable. This variable however remains difficult to measure, especially when using physiological signals. In this master’s thesis, a method is examined to establish an athlete’s mental state using real-time physiological measurements of the heart rate and the physical activity. Nine youth volleyball athletes were monitored during six trainings to assess the impact of coach interventions on their mental state. Athletic performance was established and the link with the obtained stress levels is explored. The possibility to simulate coach-related stressors is investigated and whether the extra stress generates a difference in heart rate-derived stress measures. Specific coach-related stress instants are examined more closely. The possibility to implement questionnaires is explored before summarizing the results and their link to competition. The mental HR, the raw HR, and the frequency analysis of the HRV showed no significant difference when comparing the two types of trainings. HR normalized to the physical activity suggested a higher value, around 20 bpm/m/s², in the stressful trainings. Match formats and services generated a higher mental HR (±15 bpm) compared to standard set, pass, and attack exercises. During the stress moments, specific responses were observed in all the different stress indicators. However, not all moments generated a response and not all indicators presented a response to the same stress instants. The performance during the stressful trainings appeared higher in the service exercises. Nevertheless, overall conclusions about the higher performance trend in the stressful environment could not be made and more data is needed to suggest individual trends. The results from the questionnaires were inconclusive, questioning the usefulness in underage athletes and whether a true discrepancy between the stressful and stressless training existed. We may conclude that it is hard to create a stressful environment during training but that the suggested stress indicators (especially the ones considering physical activity) could provide useful insight into specific stress moments.