Caractérisation non destructive de la proportion de carie et du module d'élasticité du bois d'érable à sucre par tomographie acoutique

L’érable à sucre est une essence abondante dans les forêts du Nord-Est de l’Amérique du Nord et très prisée pour des applications d’apparence et de structure. Cependant, la présence de la coloration et de la carie dans le bois des érables, particulièrement dans la portion nord de sa répartition géographique provoque une diminution considérable de la qualité des tiges ainsi qu’une dégradation des propriétés mécaniques et physiques du bois. Il est ainsi important de détecter et de quantifier la carie dans les peuplements d’érable à sucre. Ainsi, nous visons à évaluer le potentiel de tomographie acoustique pour la détection et la quantification de la carie sur les arbres debout d’une façon non destructive. L’objectif général de ce projet consiste à évaluer le potentiel du tomographe acoustique pour la détection de la carie dans les peuplements d’érable à sucre et l’évaluation de son impact sur les propriétés mécaniques de son bois. Plus spécifiquement, le projet vise à caractériser la proportion de la carie par tomographie acoustique; évaluer l’impact de la carie sur les propriétés mécaniques du bois notamment les modules d’élasticité statique (MOE) et dynamique (MOED) mesurés par deux techniques; évaluer le potentiel de tomographie acoustique pour prédire l’impact de la carie sur le comportement mécanique du bois. Cinquante-trois arbres ont été échantillonnés aléatoirement dans deux sites situés à La Tuque (Québec, Canada). Le MOED dépend de deux paramètres physiques soient la vitesse de propagation de l’onde sonore et la masse volumique du bois. Chaque arbre a été mesuré par le tomographe acoustique pour déterminer la variation radiale de la vitesse de propagation de l’onde sonore et une carotte a été prélevée de chaque arbre pour déterminer le profil radial de la masse volumique en utilisant le densitomètre à rayon X. Afin d’évaluer et de valider le potentiel des outils de caractérisation non destructifs (le tomographe acoustique, le densitomètre à rayon X) pour la mesure des propriétés élastiques du bois, des essais de caractérisation destructifs ont été réalisés (tests de compression et de flexion). En effet, dix-huit billes d’érable à sucre, de hauteur 50 cm, ayant différents diamètres et récoltés de deux sites de l’Abitibi-Témiscamingue (Québec, Canada), ont été analysés par les outils non destructifs (le tomographe acoustique et la méthode d’ultrason) et en même temps avec des outils destructifs afin d’établir des corrélations entre les modules d’élasticité déterminés par les deux méthodes. Les résultats suggèrent un effet significatif de la coloration et de la carie sur les propriétés mécaniques du bois. Ces propriétés diminuent du bois sain vers le bois coloré ou carié avec des pertes d’utilisation à des fins commerciales allant jusqu'à 60%. De plus, le tomographe s’avère un outil non destructif efficace pour évaluer la qualité des érables à sucre. Il peut être avantageusement substitué au tronçonnage et à la récolte de billes de bois

Editorial: Exercise intervention for prevention, management of and rehabilitation from COVID-19

exercise, prevention, rehabilitation, infection, COVID-1

Power Approaches for Implantable Medical Devices.

Implantable medical devices have been implemented to provide treatment and to assess in vivo physiological information in humans as well as animal models for medical diagnosis and prognosis, therapeutic applications and biological science studies. The advances of micro/nanotechnology dovetailed with novel biomaterials have further enhanced biocompatibility, sensitivity, longevity and reliability in newly-emerged low-cost and compact devices. Close-loop systems with both sensing and treatment functions have also been developed to provide point-of-care and personalized medicine. Nevertheless, one of the remaining challenges is whether power can be supplied sufficiently and continuously for the operation of the entire system. This issue is becoming more and more critical to the increasing need of power for wireless communication in implanted devices towards the future healthcare infrastructure, namely mobile health (m-Health). In this review paper, methodologies to transfer and harvest energy in implantable medical devices are introduced and discussed to highlight the uses and significances of various potential power sources

Exploratory study of the acute and mid-term effects of using a novel dynamic meeting environment (Aeris®) on cognitive performance and neurophysiological responses

The purpose of the present study was to assess the acute and mid-term effects of the dynamic aeris®-meeting- environment on brain activity, cognitive performance, heart rate variability (HRV), sleepiness, mental workload (EEG-MWI), as well as local experienced discomfort (LED) in healthy adults. Twenty-four healthy adults (16 females, age: 25.2 ± 3.1 years old) were randomly assigned to either the control (i.e., conventional meeting environment, CG) or experimental (Aeris® dynamic meeting-environment, DG) group with a 1:1 allocation. Participants reported to the laboratory on two test sessions separated by a 2-week intervention period (5 meetings of 90 min each week). Spontaneous resting EEG and HRV activities, as well as attentional (D2-R test) and vigilance (PVT) cognitive performances, sleepiness perceptions, and EEG-MWI, were recorded at the beginning of each test session and immediately following the 90-min meeting. The LED was measured pre- and post-intervention. The changes (Δ) from pre- to post-90 min meeting and from pre- to post- intervention were computed to further examine the acute and mid-term effects, respectively. Compared to the CG, the DG showed higher Δ (pre-post 90 min-meeting) in fronto-central beta (z = −2.41, p = 0.016, d = 1.10) and gamma (z = −2.34, p = 0.019, d = 0.94) frequencies at post-intervention. From pre- to post-intervention, only the DG group showed a significant increase in fronto-central gamma response (Δ) to the meeting session (z = −2.09, p = 0.04, d = 1.08). The acute use of the Aeris®-meeting-environment during the 90-min meeting session seems to be supportive for (i) maintaining vigilance performance, as evidenced by the significant increase in N-lapses from pre- to post-90 min session only in the CG (p = 0.04, d = 0.99, Δ = 2.5 ± 3 lapses), and (ii) improving alertness, as evidenced by the lower sleepiness score (p = 0.05, d = −0.84) in DG compared to CG. The mid-term use of such an environment showed to blind the higher baseline values of EEG-MWI recorded in DG compared to CG (p = 0.01, d = 1.05) and may prevent lower-back discomfort (i.e., a significant increase only in CG with p = 0.05 and d = 0.78), suggesting a less mentally and physically exhausting meeting in this environment. There were no acute and/or mid-term effects of the dynamic meeting environment on any of the HRV parameters. These findings are of relevance in the field of neuroergonomics, as they give preliminary support to the advantages of meeting in a dynamic office compared to a static office environment

Relationship between motor and cognitive learning abilities among primary school-aged children

Background: The relationship between motor and cognitive development has already been proven in young children. However, in relation to the academic achievement the association between motor and cognitive performance still not well established. Therefore, the aim of this study was to examine the levels of motor and cognitive learning abilities and their independent and combined associations among German primary school-children.Methods: Participants were (n = 197) between the ages of six to eight. The German motor test (DMT), the cognitive abilities test (KFT), height, weight, and body mass index (BMI) were measured.Results: ANOVA testing found that boys perform better in long jumping and in the six minutes running test while girls perform better in balancing backwards and in deductive thinking test (p < 0.05). With maturation from ages six to eight the achievement level of both populations showed a higher performance in motor and cognitive learning abilities (p < 0.001). Concerning the combined and independent associations between the tested abilities, a significant correlation was shown between total motor and total cognitive learning abilities (p < 0.001, r = 0.60) with higher contribution of balancing backwards, six minutes running and push-up levels (r = 0.63, r = 0.62, r = 0.60, respectively) in the performance of the cognitive learning abilities (i.e. mathematical thinking, r = 0.62 and language understanding, r = 0.59).Conclusions: In conclusion, fostering the childrens’ physical fitness during the primary school age could enhance both motor and cognitive learning abilities related to the academic achievement