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In this paper we present various educational activities with Photonics Explorer, an educational kit developed by the photonics research team B - PHOT at VUB (Vrije Universiteit Brussel) for students at secondary schools. The concept is a ‘lab-in-a-box’ that enables students of the 2 nd and 3 rd grade to do photonics experiments themselves at school with lasers, LEDs, lenses, optical fibers, and other high-tech components. Even though, the kit was developed for the secondary schools, we use experiments from the kit also for some other teaching activities such as lectures at the university, photonics workshops for teachers and children at primary/secondary schools or for events such as children's/youth's university or the night of sciences. In the frame of Austrian based project Phorsch! we have organized most of these activities which will be presented here.
Fibrin hydrogels have proven highly suitable scaffold materials for skeletal muscle tissue engineering in the past. Certain parameters of those types of scaffolds, however, greatly affect cellular mechanobiology and therefore the myogenic outcome. The aim of this study was to identify the influence of apparent elastic properties of fibrin scaffolds in 2D and 3D on myoblasts and evaluate if those effects differ between murine and human cells. Therefore, myoblasts were cultured on fibrin-coated multiwell plates (“2D”) or embedded in fibrin hydrogels (“3D”) with different elastic moduli. Firstly, we established an almost linear correlation between hydrogels’ fibrinogen concentrations and apparent elastic moduli in the range of 7.5 mg/ml to 30 mg/ml fibrinogen (corresponds to a range of 7.7–30.9 kPa). The effects of fibrin hydrogel elastic modulus on myoblast proliferation changed depending on culture type (2D vs 3D) with an inhibitory effect at higher fibrinogen concentrations in 3D gels and vice versa in 2D. The opposite effect was evident in differentiating myoblasts as shown by gene expression analysis of myogenesis marker genes and altered myotube morphology. Furthermore, culture in a 3D environment slowed down proliferation compared to 2D, with a significantly more pronounced effect on human myoblasts. Differentiation potential was also substantially impaired upon incorporation into 3D gels in human, but not in murine, myoblasts. With this study, we gained further insight in the influence of apparent elastic modulus and culture type on cellular behavior and myogenic outcome of skeletal muscle tissue engineering approaches. Furthermore, the results highlight the need to adapt parameters of 3D culture setups established for murine cells when applied to human cells.
Peripheral nerve injuries pose a major clinical concern world-wide, and functional recovery after segmental peripheral nerve injury is often unsatisfactory, even in cases of autografting. Although it is well established that angiogenesis plays a pivotal role during nerve regeneration, the influence of lymphangiogenesis is strongly under-investigated. In this study, we analyzed the presence of lymphatic vasculature in healthy and regenerated murine peripheral nerves, revealing that nerve autografts contained increased numbers of lymphatic vessels after segmental damage. This led us to elucidate the interaction between lymphatic endothelial cells (LECs) and Schwann cells (SCs) in vitro. We show that SC and LEC secretomes did not influence the respective other cell types' migration and proliferation in 2D scratch assay experiments. Furthermore, we successfully created lymphatic microvascular structures in SC-embedded 3D fibrin hydrogels, in the presence of supporting cells; whereas SCs seemed to exert anti-lymphangiogenic effects when cultured with LECs alone. Here, we describe, for the first time, increased lymphangiogenesis after peripheral nerve injury and repair. Furthermore, our findings indicate a potential lymph-repellent property of SCs, thereby providing a possible explanation for the lack of lymphatic vessels in the healthy endoneurium. Our results highlight the importance of elucidating the molecular mechanisms of SC-LEC interaction.
Temporary scaffolds that mimic the extracellular matrix's structure and provide a stable substratum for the natural growth of cells are an innovative trend in the field of tissue engineering. The aim of this study is to obtain and design porous 2D fibroin-based cell matrices by femtosecond laser-induced microstructuring for future applications in muscle tissue engineering. Ultra-fast laser treatment is a non-contact method, which generates controlled porosity-the creation of micro/nanostructures on the surface of the biopolymer that can strongly affect cell behavior, while the control over its surface characteristics has the potential of directing the growth of future muscle tissue in the desired direction. The laser structured 2D thin film matrices from silk were characterized by means of SEM, EDX, AFM, FTIR, Micro-Raman, XRD, and 3D-roughness analyses. A WCA evaluation and initial experiments with murine C2C12 myoblasts cells were also performed. The results show that by varying the laser parameters, a different structuring degree can be achieved through the initial lifting and ejection of the material around the area of laser interaction to generate porous channels with varying widths and depths. The proper optimization of the applied laser parameters can significantly improve the bioactive properties of the investigated 2D model of a muscle cell matrix.
Keywords: biopolymers; femtosecond laser processing; muscle cell matrix 2D model; muscle tissue engineering; silk fibroin.
Perspectives on Virtual Reality in Higher Education for Robotics and Related Engineering Disciplines
(2022)
Industrial engineering education has a strong focus on and affinity towards technology. While Virtual Reality hardware and applications advance and learning behaviour changes, it is particularly interesting to determine the possible use of Virtual Reality for teaching engineering subjects, for example fundamentals of robotics.
This paper presents a study which examines the possible use of Virtual Reality learning environments at higher learning institutions. The study shows perspectives of students and lecturers and identifies opportunities and challenges for the use of Virtual Reality in industrial engineering education. The results of the indicated study show that the participants have a positive attitude towards Virtual Reality and strong motivation for in class use. The study results also suggest, that Virtual Reality content creation should be included in engineering curricula.
In order to enhance the strength of 3D-printed parts made of polymer materials and reduce the anisotropy caused by the fused filament fabrication process, this paper proposes an inter-layer interleaved composite path planning method based on the directional partition of the principal stress field. This method not only ensures intra-layer reinforcement under specific working conditions but also increases the strength of the printed part by enhancing the adhesion of adjacent layers through staggered filling between layers. The mechanical performance is improved by 10 to 30% compared to other conventional filling patterns such as the zigzag filling algorithm. Inter-layer interleaved composite enhancement path planning method is suitable for path planning of structures with complex shapes and is easily integrated into existing general computer-aided engineering processes.
Hochschulen und Studiengänge sprechen Studieninteressierte nicht
bevölkerungsrepräsentativ an. Nach einem kurzen Abriss der aktuellen Lage und
der Diversitätsdimensionen werden anhand einer adaptierten Form der „4R-
Methode“ des Gender-Mainstreamings Kommunikationsarten, -medien und
-ebenen mit Blick auf Kommunizierende und Kontexte beleuchtet. Dieser Beitrag
soll Hochschulen und Studiengängen einen einfachen Leitfaden an die Hand
geben, die eigene Sprache auf den verschiedenen Kommunikationskanälen
kritisch zu reflektieren und inkludierender zu gestalten, um Stereotypisierung zu
vermeiden und alle anzusprechen
Dry powder inhalers are used by a large number of patients worldwide to treat respiratory diseases. The objective of this work is to experimentally investigate changes in aerosol particle diameter and particle number concentration of pharmaceutical aerosols generated by four dry powder inhalers under realistic inhalation and exhalation conditions. To simulate patients undergoing inhalation therapy, the active respiratory system model (xPULM™) was used. A mechanical upper airway model was developed, manufactured, and introduced as a part of the xPULM™ to represent the human upper respiratory tract with high fidelity. Integration of optical aerosol spectrometry technique into the setup allowed for evaluation of pharmaceutical aerosols. The results show that there is a significant difference (p < 0.05) in mean particle diameter between inhaled and exhaled particles with the majority of the particles depositing in the lung, while particles with the size of (>0.5 μm) are least influenced by deposition mechanisms. The fraction of exhaled particles ranges from 2.13% (HandiHaler®) over 2.94% (BreezHaler®), and 6.22% (Turbohaler®) to 10.24% (Ellipta®). These values are comparable to previously published studies. Furthermore, the mechanical upper airway model increases the resistance of the overall system and acts as a filter for larger particles (>3 μm). In conclusion, the xPULM™ active respiratory system model is a viable option for studying interactions of pharmaceutical aerosols and the respiratory tract regarding applicable deposition mechanisms. The model strives to support the reduction of animal experimentation in aerosol research and provides an alternative to experiments with human subjects.
Ziel dieser Studie war das überlagerte Elektromyogramm (ueEMG) und das decompositionierte (dEMG) auf deren Reliabilität und Aussagekraft zu überprüfen. Hierfür vollzogen zehn gesunde männliche Probanden zu drei Testzeitpunkten isometrische Ermüdungsmessungen. Hintergrund Bei der Messung des ueEMG werden die Motor Units Aktionspotentiale (MUAPS) elektrisch überlagert. Physiologische Muskelermüdung zeigt sich hier unter anderem in der Veränderung des Frequenzspektrums und der Signalamplitude. Letzteres steigt bei Ermüdung an, wohingegen die mediane Frequenz (MF) sinkt. Eine weitere Möglichkeit die Muskelermüdung mittels Oberflächen-EMG zu ermitteln ist die Anwendung des dEMGs. Dieses ermöglicht mithilfe einer Mustererkennungssoftware einzelne MUAPS zu erkennen. Studien zeigten, dass aktive Motor Units (MU) bei wiederholten oder anhaltenden submaximalen Kontraktionen als Muskelermüdung ihre Feuerungsrate erhöhen und neue MU rekrutiert werden. Bisher wurden diese Methoden jeweils einzeln betrachtet. Um sicherzustellen welcher Ansatz für klinische Daten geeigneter ist, wurden Datensätze zu beiden Methoden gleichzeitig generiert und hinsichtlich ihrer Aussagekraft und Wiederholbarkeit mit statistischen Mitteln verglichen.