1,121 research outputs found
Christophe Flament, Le monnayage en argent d’Athènes de l’époque archaïque à l’époque hellénistique (c. 550 – c. 40 av. J.-C.)., 2007
No full textVan Driessche-Godfrind Véronique. Christophe Flament, Le monnayage en argent d’Athènes de l’époque archaïque à l’époque hellénistique (c. 550 – c. 40 av. J.-C.)., 2007. In: L'antiquité classique, Tome 77, 2008. pp. 616-617
Fabrice Delrieux, Les monnaies des cités grecques de la Basse Vallée de l’Harpasos en Carie (IIe s. a. C. – IIe s. p. C.). Bordeaux, Ausonius, 2008
No full textVan Driessche-Godfrind Véronique. Fabrice Delrieux, Les monnaies des cités grecques de la Basse Vallée de l’Harpasos en Carie (IIe s. a. C. – IIe s. p. C.). Bordeaux, Ausonius, 2008. In: L'antiquité classique, Tome 79, 2010. pp. 610-611
Het hof ter Welle te Beveren /
No full textOverdruk uit: Annalen van de Koninklijke oudheidkundige kring van het Land van Waas; (1976)79, p. 147-15
Veroudering en spierfunctie: Bijzondere aandacht voor responstijd, contractietype, bewegingscomplexiteit en mate van versnelling
No full textLife expectancy is rising globally, which is a human success story. However, aging is accompanied by a loss of functional performance capacity and a higher risk of falling, leading to a loss of autonomy. Due to these changes, the rising medical costs and the higher need for primary health care, a major clinical and economic burden for the society exists. Therefore, detection of early declines in muscular function during aging and prevention of the loss in functional performance capacity are of paramount importance. However, the current methodologies used in clinical practice are rather limited to capture the complex functioning of muscles during human movements and hence the age-related decline in muscular function. Factors such as response time, contraction type, movement complexity and acceleration rate are shown to have a clear influence on muscular function. However, how these factors are affected by aging is not well understood. Therefore, we aimed to identify age-related changes in muscular function and get more insight into the functional outcomes of the aging process by investigating the effect of aging on muscular function with the focus on response time, contraction type, movement complexity and acceleration rate. In addition, we aimed to gain a better insight into the underlying mechanisms of the age-related changes in muscular function, which could help to develop effective strategies to counteract these age-related deteriorations. Generally, this doctoral thesis, which consists of three chapters, aims to create awareness in clinical practice about less known age-related problems that can have a high impact and to bring new insights into the field of aging research to help finding solutions for the loss of functionality.
Chapter 1 focusses on factors such as response time and contraction type. More specifically, the reliability and the age-related decline of time-dependent measures of knee extensor function obtained through isotonic testing is investigated. In article 1, it is shown that maximal and time-dependent measures of muscular function such as pP and RPD are good to highly reliable in older adults. Therefore, pP and RPD can be considered as consistent measures of muscular function. In article 2, it is found that RPD differentiates more between young and older adults compared with pP, due to an additional age-related increase in the time to pP. Furthermore, all power-related parameters show a strong relationship with functional performance tests, such as 7.5-meter fast walk, timed-up-and-go and stair climbing, in well-functioning community-dwelling older adults. These results underline the importance of time-dependent measures to detect age-related changes in muscular function, in particular they emphasize the inability to generate power rapidly at older age.
Chapter 2 focusses on movement complexity. In article 3, the effect of age on power production of the leg extensors in single- versus multi-joint movements is evaluated across the adult life span. In both single- and multi-joint tests, it is shown that the age-related decline in RPD exceeds the decline in pP. In addition, it is found that RPD declines more in the multi-joint compared with the single-joint test. This phenomenon is true for tests at different velocities. Moreover, it is found that RPD multi-joint is more associated with squat jump height compared with RPD single-joint. Therefore, research and clinical practice should consider focusing on the initial phase of rapid power development and multi-joint testing for the detection of functional disability during aging.
Chapter 3 investigates the effect of aging on power production at different accelerations and aims to gain a better insight in the underlying mechanisms of the age-related decline in muscular function in terms of neural activation and in vivo fascicle behavior. In article 4, it is shown that RPD largely declines with aging with the steepest decline at the highest acceleration. Neuromuscular activation declines more at higher compared to lower acceleration for rectus femoris (RF) and vastus lateralis (VL) muscles. The age-related changes at high relative to lower acceleration in RF and VL activity are associated with the age-related decline in RPD across the sample. These findings emphasize the magnitude of the age-related decline in leg extensor RPD in response to abrupt changes in movement velocity across the adult life span and its association with impairments in neuromuscular activity. In article 5, it is shown that VL fascicle shortening and shortening velocity increase significantly with aging with no difference between accelerations. This age-related change is mainly due to a higher shortening during the phase of electromechanical delay. VL fascicle shortening and shortening velocity are positively associated with RPD. These findings demonstrate that the age-related decline in RPD in fast actions is accompanied by an increase in fascicle shortening and shortening velocity. While in vivo fiber shortening velocity seems to be no limiter, specific fiber force may have a bigger influence on rapid power production at advancing age than its capacity to shorten fast. Increased VL fascicle shortening might result in less optimal fiber lengths, which may be due to decreased stiffness of the series elastic element with aging.
All together, the findings of the different papers highlight that time-dependent measures of muscular function could be considered as potential identifiers of muscular aging in research and clinical practice, especially in dynamic, multi-joint testing at high accelerations. Preventive exercise interventions should not only focus on improving muscle mass and maximal strength, but also neural activation, fiber properties and tendon stiffness.status: Publishe
Financieringsmodellen van ziekenhuis- en transmurale zorg, voor toepassing in het vernieuwd Vlaamse gezondheidsbeleid
No full textnot availabl
Financieringsmodellen van ziekenhuis- en transmurale zorg, voor toepassing in het vernieuwd Vlaamse gezondheidsbeleid
No full textnot availabl
Sign patterns that allow strong eventual nonnegativity
No full textA new class of sign patterns contained in the class of sign patterns that allow eventual nonnegativity is introduced and studied. A sign pattern is potentially strongly eventually nonnegative (PSEN) if there is a matrix with this sign pattern that is eventually nonnegative and has some power that is both nonnegative and irreducible. Using Perron-Frobenius theory and a matrix perturbation result, it is proved that a PSEN sign pattern is either potentially eventually positive or r-cyclic. The minimum number of positive entries in an n x n PSEN sign pattern is shown to be n, and PSEN sign patterns of orders 2 and 3 are characterized.This article is published as Catral, M., C. Erickson, L. Hogben, D. Olesky, and P. Van Den Driessche. "Sign patterns that allow strong eventual nonnegativity." The Electronic Journal of Linear Algebra 23 (2012): 1-10. DOI: 10.13001/1081-3810.1502. Posted with permission.</p
Ontwerpstudio C
No full textWorking in Venice means working in a context that is geographically, hydrographically and historically strongly defined. A city where it is nearly impossible to intervene without positioning oneselves with respect to its cultural context, its history, its building traditions. A city where the introduction of modernity not only has a long history of resistance, but is also a necessity for its survival. Hence, Venice is a good place to reflect upon issues at stake in current architectural practice world wide, in particular the many problematic aspects of globalization in architecture and urban planning. Venice is a good context to think about what remains of the the power of the project within an architectural production of ‘a world without qualities’; a good context to reflect upon possible resistances against a world of non-lieux (Marc Augé, 1992). This text explains the aims of our Master Studio, 'Ontwerpstudio C', and illustrates its intentions with three student projects, made during the second semester of 2012-2013
The surface chemistry of metal oxide nanocrystals : a solution NMR study
No full textCeramic nanocrystals (NCs) are of general interest because of their potential applications in catalysis, gas sensing, LED’s, and other areas. However, the formed particles need to be processed in order to be used in a specific application. Gaining knowledge about the surface chemistry of the NCs is therefore of special importance and NMR provides us with the tools to address this due to the extensive T2 relaxation of bound ligands.
HfO2 NCs are solvothermally synthesized in benzyl alcohol with microwave heating. The surface of the obtained charge stabilized NCs can subsequently be modified with fatty acids and oleylamine to allow solubility in nonpolar solvents.1 During this process, clusters are broken up and the constituent particles are obtained. We present here a detailed study of the fundamental acid/base processes during the surface modification, using 1D proton, NOESY and DOSY NMR. We demonstrate that there is a crucial difference in surface chemistry between metal oxide NCs and the more widely studied chalcogenide NCs, such as PbS and CdSe.2 The electronegative property of oxygen allows for protons to be accommodated at the surface of HfO2 NCs which was shown with the help of exchange experiments with deuterated acid. The binding event of a carboxylic acid on a metal oxide NC is thus a dissociative process, see scheme 1.
Subsequently, we show the practical implications of these findings. First, we show that ligand exchange reactions, which were considered impossible, do take place at the metal oxide NC surface. We examined the exchange of X-type ligands for L-type ligands by performing titration experiments which were followed by 1D proton and DOSY NMR. Secondly, we demonstrate that acid catalyzed organic reactions could proceed in the presence of the HfO2 NCs due to the surface attached protons. As an example of such catalytic process, we monitored in situ the esterification of ethanol and oleic acid with 1D proton NMR and characterized the final compound with HMBC, HSQC and COSY.
In conclusion, metal oxide NCs hold protons on the surface, in contrast to metal selenides or sulfides. This property allows unexpected catalytic activity and ligand exchange to take place.
1. De Roo, J.; De Keukeleere, K.; Feys, J.; Lommens, P.; Hens, Z.; Van Driessche, I. J. Nanopart. Res. 2013, 15, 1778.
2. De Roo, J.; Van den Broeck, F.; De Keukeleere, K.; Martins, J. C.; Van Driessche, I.; Hens, Z. J. Am. Chem. Soc. 2014, 136, 9650-9657
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