333 research outputs found
[photograph] Portret van Richard Jean Raepsaet.
No full textOp achterzijde foto staat handgeschreven nota in potlood : "Chamoin R-J Raepsaet"Op drager onder foto : handgeschreven nota in inkt : "Richard Jean Raepsaet. / Vicaire général, archidiacre, doyen du chapitre de / S. Bavon et directeur des dites écoles. (Dominicales Episcopales) / Chevalier des ordres de Léopold et de la croix de Fer. / Né à Audenarde le 7 Nov' 1792, décédé à Gand le 21 Octobre 1863. / De Heer Raepsaet voormalige seminarist te Gent in 1813, werd van daer naer / Wezel gestuert als soldaat. Bij zijne wederkomst in Gent, benoemde men hem / tot lid van l'Association Philantropique Belge des frères d'armes des anciennes / armées de l'Ampire français. / Hij ontving deze vereering openhertig, zeggende dat hij wel een oud gediende is / maer ook een der oudste deserteurs."Bijzondere collectie
Essay : De rol van plasmiden van L. lactis subsp. lactis in kaaszuursels
No full textDe begeleider en/of auteur heeft geen toestemming gegeven tot het openbaar maken van de scriptie.
The supervisor and/or the author did not authorize public publication of the thesis.
Augmented reality turning cues to reduce freezing of gait in Parkinson’s disease
No full textBackground: Freezing of gait (FOG) – defined as: brief, episodic absence or marked reduction of forward progression of the feet, despite the intention to walk – is a debilitating motor symptom that occurs in up to 60% of patients with Parkinson’s disease (PD) . Turning in place is arguably the most frequent trigger for FOG. External cueing, using visual or auditory cues, has shown to be a valuable strategy to prevent or overcome FOG. In this study we have used smart glasses for interactive visual cueing in augmented reality (AR) during turning in place. The cues consist of targets surrounding the user and a Pacman figure, whose movement is linked to head rotation. The targets can be interactively reached with the Pacman figure by turning around. Our cueing system is intended to promote goal-directed movement, to direct the attention to gait and to provide spatial reference for enforcing appropriate amplitude generation.
Aims: We investigated the effectivity of our AR visual cueing system in reducing FOG severity and improving gait performance. Furthermore, we assessed the relative effectivity of our AR cueing system, compared to conventional auditory cueing.
Methods: We tested 8 subjects with PD and regular FOG during ‘end of dose’ state. Subjects performed 180 degrees turns around the axis during different cueing conditions: visual, auditory or no cueing. FOG severity was rated by an expert clinician using video recordings, and gait performance was measured using an inertial measurement system. Our endpoints were: number of FOG episodes, time spent freezing, stride length, step height, turn time, cadence and stride time variability.
Results: We found no significant difference in the number of FOG episodes, nor in the percentage of time spent freezing, between cueing conditions in the tested group of patients. We observed large between-subject variability in the effects of different cueing conditions on FOG severity. Step height was significantly decreased in the visual cueing condition when compared to other conditions. There were no significant differences in the median turn time, stride length or cadence between different cueing conditions. The variability of stride time was significantly reduced in the auditory cueing condition, compared to the control and visual cueing conditions.
Conclusion: Our AR visual cueing system did not significantly reduce FOG severity. On the contrary, rather than improving gait performance, it significantly decreased the step height. Auditory cueing significantly reduced the variability of stride time, but was, unexpectedly, ineffective in reducing FOG severity and improving other gait parameters. These findings may either reflect some primary incompatibility of external cueing for turning in place, or limitations to our cueing system. Further and larger-scale research is required to investigate effectivity of AR visual cueing for reduction of FOG severity and improvement of gait performance during turning in place. Points of improvement in future cue designs may include the use of stimuli that provide spatial information that is directly linked to gait execution; provide an explicit goal to reduce required action selection processing; and minimize distraction. Implementation of external cueing for ambulant treatment of FOG during turning in place, may require a personalized approach
De bereiding van tetra-aethyllood: 2e gedeelte: bereiding van aethylchloride
No full textDocument(en) uit de collectie Chemische ProcestechnologieDelftChemTechApplied Science
Cortical mechanisms underlying low-level motion processing in the visual system of human and non-human primates
No full textBistability and Stabilization of Human Visual Perception under Ambiguous Stimulation
No full textWe discuss a computational model that describes stabilization of percept choices under intermittent viewing of an ambiguous visual stimulus at long stimulus intervals. Let Toff and Ton be the time that the stimulus is off and on, respectively. The behavior was studied by direct numerical simulation in a grid of (Toff, Ton) values in a 2007 paper of Noest, van Ee, Nijs, and van Wezel. They found that both alternating and repetitive sequences of percepts can appear stably, sometimes even for the same values of Toff and Ton. Longer Toff, however, always leads to a situation where, after transients, only repetitive sequences of percepts exist. We incorporate Toff and Ton explicitly as bifurcation parameters of an extended mathematical model of the perceptual choices. We elucidate the bifurcations of periodic orbits responsible for switching between alternating and repetitive sequences. We show that the stability borders of the alternating and repeating sequences in the (Toff, Ton) -parameter plane consist of curves of limit point and period-doubling bifurcations of periodic orbits. The stability regions overlap, resulting in a wedge with bistability of both sequences. We conclude by comparing our modeling results with the experimental results obtained by Noest, van Ee, Nijs, and van Wezel
Netwerkende breinen
No full textHoe leidt een netwerk van miljarden zenuwcellen tot bewuste en onbewuste waarneming? Hoe wordt dit omgezet in zinvolle acties? Daarvoor is het van belang apparatuur te ontwikkelen om hersenactiviteit te meten en te veranderen. Deze fundamentele kennis en nieuwe apparatuur kunnen worden gebruikt voor het nabouwen en uiteindelijk beinvloeden van hersenfuncties. De belangrijkste toepassing daarvan is begrip krijgen van en interventies vinden voor hersenziektes als epilepsie, dementie, schizofrenie, ziekte van Parkinson en depressies
Provoking freezing of gait in clinical practice: turning in place is more effective than stepping in place
No full textProvoking Freezing of Gait in Clinical Practice: Turning in Place is More Effective than Stepping in Place. K Dijsseldonk vanY WangR Wezel vanBR BloemJ Nonnekes..
Biomimetic Architectures for Peripheral Nerve Repair: A Review of Biofabrication Strategies.
No full textBiofabrication techniques have endeavored to improve the regeneration of the peripheral nervous system (PNS), but nothing has surpassed the performance of current clinical practices. However, these current approaches have intrinsic limitations that compromise patient care. The “gold standard” autograft provides the best outcomes but requires suitable donor material, while implantable hollow nerve guide conduits (NGCs) can only repair small nerve defects. This review places emphasis on approaches that create structural cues within a hollow NGC lumen in order to match or exceed the regenerative performance of the autograft. An overview of the PNS and nerve regeneration is provided. This is followed by an assessment of reported devices, divided into three major categories: isotropic hydrogel fillers, acting as unstructured interluminal support for regenerating nerves; fibrous interluminal fillers, presenting neurites with topographical guidance within the lumen; and patterned interluminal scaffolds, providing 3D support for nerve growth via structures that mimic native PNS tissue. Also presented is a critical framework to evaluate the impact of reported outcomes. While a universal and versatile nerve repair strategy remains elusive, outlined here is a roadmap of past, present, and emerging fabrication techniques to inform and motivate new developments in the field of peripheral nerve regeneration
Eye Blink Changes During Freezing of Gait in Parkinson's Disease
No full textFreezing of gait (FOG) in Parkinson's Dis-
ease (PD) patients can have a signi cant impact on the
daily lives of patients. Increased cognitive load has been
related to more FOG. Besides, cognitive load has been
found to have an in
uence on blink rate. However, the
relationship between FOG and blink rate has not yet
been investigated. Eye blink rates of 15 OFF medica-
tion PD patients were compared over three FOG stages
(non-FOG, pre-FOG & FOG). We found blink rate to
signi cantly decrease during FOG episodes as compared
to pre-FOG. Individual blink rate analyses yielded sig-
ni cant di erences for 5 out of 15 subjects. In to-
tal, 711 FOG episodes were measured. These results
might indicate subjects experience more load during
FOG episodes as compared to pre-FOG. Besides cog-
nitive load,
uctuations in dopamine modulation and
anxiety might also play a role in the processes underly-
ing and preceding FOG. These results contribute to ex-
posing physiological correlates of FOG. Moreover, these
results could potentially nd useful applications in de-
tecting and predicting FOG
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