225 research outputs found

    Application of design of experiments (DoE) for optimised production of micro- and mesoporous Norway spruce bark activated carbons

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    In this work, Norway spruce (Picea abies (Karst) L.) bark was employed as a precursor to prepare activated carbon using zinc chloride (ZnCl2) as a chemical activator. The purpose of this study was to determine optimal activated carbon (AC) preparation variables by the response surface methodology using a Box-Behnken design (BBD) to obtain AC with high specific surface area (S-BET), mesopore surface area (S-MESO), and micropore surface area (S-MICR). Variables and levels used in the design were pyrolysis temperature (700, 800, and 900 degrees C), holding time (1, 2, and 3 h), and bark/ZnCl2 impregnation ratio (1, 1.5, and 2). The optimal conditions for achieving the highest S-BET were as follows: a pyrolysis temperature of 700 degrees C, a holding time of 1 h, and a spruce bark/ZnCl2 ratio of 1.5, which yielded an S-BET value of 1374 m(2) g(-1). For maximised mesopore area, the optimal condition was at a pyrolysis temperature of 700 degrees C, a holding time of 2 h, and a bark/ZnCl2 ratio of 2, which yielded a S-MESO area of 1311 m(2) g(-1), where mesopores (S-MESO%) comprised 97.4% of total S-BET. Correspondingly, for micropore formation, the highest micropore area was found at a pyrolysis temperature of 800 degrees C, a holding time of 3 h, and a bark/ZnCl2 ratio of 2, corresponding to 1117 m(2) g(-1), with 94.3% of the total S-BET consisting of micropores (S-MICRO%). The bark/ZnCl2 ratio and pyrolysis temperature had the strongest impact on the S-BET, while the interaction between temperature and bark/ZnCl2 ratio was the most significant factor for S-MESO. For the S-MICRO, holding time was the most important factor. In general, the spruce bark AC showed predominantly mesoporous structures. All activated carbons had high carbon and low ash contents. Chemical characterisation indicated that the ACs presented disordered carbon structures with oxygen functional groups on the ACs' surfaces. Well-developed porosity and a large surface area combined with favourable chemical composition render the activated carbons from Norway spruce bark with interesting physicochemical properties. The ACs were successfully tested to adsorb sodium diclofenac from aqueous solutions showing to be attractive products to use as adsorbents to tackle polluted waters

    Simulation of a geothermal aquifer storage in Brussels showing the need for a better balanced system with regards to the local hydrogeological conditions

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    An Aquifer Thermal Energy Storage (ATES) system was started in 2014 in the center of Brussels using the Landenian confined aquifer for heat and cold needs of an administrative building. Unfortunately, the imbalance between the injection of warm and cold water combined with the local hydrogeological conditions, has led rapidly to thermal interferences between the heat plume and the cold wells. A second ATES system located nearby started to operate around August 2017 for the heat and cold needs of another large administrative building. In the scope of the MUSE project (GeoERA/ERA-NET program), a numerical model was built using FEFLOWÂź to simulate groundwater flow and heat transport in the confined aquifer. After calibration on the available piezometric and temperature data, realistic scenarios were simulated to determine possible interferences and to image the year after year persisting and growing heat plume in the aquifer. Results show that even if the heat plumes of the two systems had come into contact, the influence of the second system on the first one was negligible during the first two years of joint operation. Indeed, for a longer period, simulated results pointed out that due to the thermal imbalance and the limited advection in the aquifer, the groundwater temperature would rise inexorably in the warm and cold wells of both systems. A business as usual scenario will lead to a decrease in efficiency for both systems. This case-study is showing how it could be difficult to find an optimum with regards to the local hydrogeological conditions. If advection is very important, thermal energy cannot actually be stored locally as heat and cold plumes are transported far away from the wells. On the contrary, if advection is limited, a global thermal balance is required for hot and cold injections. If advection is moderate (as in this case study), a detailed simulation of the groundwater flow and heat transport in the aquifer is required to find out if the annual imbalance can be managed in relation to the specific local hydrogeological conditions

    Neurocranial development of the coelacanth and the evolution of the sarcopterygian head

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    The neurocranium of sarcopterygian fishes was originally divided into an anterior (ethmosphenoid) and posterior (otoccipital) portion by an intracranial joint, and underwent major changes in its overall geometry before fusing into a single unit in lungfishes and early tetrapods. Although the pattern of these changes is well-documented, the developmental mechanisms that underpin variation in the form of the neurocranium and its associated soft tissues during the evolution of sarcopterygian fishes remain poorly understood. The coelacanth Latimeria is the only known living vertebrate that retains an intracranial joint. Despite its importance for understanding neurocranial evolution, the development of the neurocranium of this ovoviviparous fish remains unknown. Here we investigate the ontogeny of the neurocranium and brain in Latimeria chalumnae using conventional and synchrotron X-ray microcomputed tomography as well as magnetic resonance imaging, performed on an extensive growth series for this species. We describe the neurocranium at the earliest developmental stage known for Latimeria, as well as the major changes that the neurocranium undergoes during ontogeny. Changes in the neurocranium are associated with an extreme reduction in the relative size of the brain along with an enlargement of the notochord. The development of the notochord appears to have a major effect on the surrounding cranial components, and might underpin the formation of the intracranial joint. Our results shed light on the interplay between the neurocranium and its adjacent soft tissues during development in Latimeria, and provide insights into the developmental mechanisms that are likely to have underpinned the evolution of neurocranial diversity in sarcopterygian fishes

    Zwitterionic polymer ligands: An ideal surface coating to totally suppress protein-nanoparticle corona formation?

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    International audienceIn the last few years, zwitterionic polymers have been developed as antifouling surface coatings. However, their ability to completely suppress protein adsorption at the surface of nanoparticles in complex biological media remains undemonstrated. Here we investigate the formation of hard (irreversible) and soft (reversible) protein corona around model nanoparticles (NPs) coated with sulfobetaine (SB), phosphorylcholine (PC) and carboxybetaine (CB) polymer ligands in model albumin solutions and in whole serum. We show for the first time a complete absence of protein corona around SB-coated NPs, while PC-and CB-coated NPs undergo reversible adsorption or partial aggregation. These dramatic differences cannot be described by naĂŻve hard/soft acid/base electrostatic interactions. Single NP tracking in the cytoplasm of live cells corroborate these in vitro observations. Finally, while modification of SB polymers with additional charged groups lead to consequent protein adsorption, addition of small neutral targeting moieties preserves antifouling and enable efficient intracellular targeting

    Orvieto, Angiolo

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    Objective. Although regular physical activity is an effective secondary prevention strategy for patients with a chronic disease, it is unclear whether patients change their daily physical activity after being diagnosed. Therefore, the aims of this study were to (1) describe changes in levels of physical activity in middle-aged women before and after diagnosis with a chronic disease (heart disease, diabetes, asthma, breast cancer, arthritis, depression); and to (2) examine whether diagnosis with a chronic disease affects levels of physical activity in these women. Methods. Data from 5 surveys (1998-2010) of the Australian Longitudinal Study on Women's Health (ALSWH) were used. Participants (N = 4840, born 1946-1951) completed surveys every three years, with questions about diseases and leisure time physical activity. The main outcome measure was physical activity, categorized as: nil/sedentary, low active, moderately active, highly active. Results. At each survey approximately half the middle-aged women did not meet the recommended level of physical activity. Between consecutive surveys, 41%-46% of the women did not change, 24%-30% decreased, and 24%-31% increased their physical activity level. These proportions of change were similar directly after diagnosis with a chronic disease, and in the years before or after diagnosis. Generalized estimating equations showed that there was no statistically significant effect of diagnosis with a chronic disease on levels of physical activity in women. Conclusion. Despite the importance of physical activity for the management of chronic diseases, most women did not increase their physical activity after diagnosis. This illustrates a need for tailored interventions to enhance physical activity in newly diagnosed patients. (C) 2015 Elsevier Inc. All rights reserved

    Cartographier en 3D avec MapIt : une plus-value pour un parcours de professionnalisation selon la perspective Ă©tudiante

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    Implication Statement During the pandemic, the MapIt app was integrated into an occupational therapy program to support remote learning of built environment adaptation. MapIt maps rooms in a home, then generates a 3D model for viewing and taking virtual measurements. The students express that the use of MapIt during their training leads to embodying the roles expected of an occupational therapist. To inspire other good pedagogical ideas, this article presents how MapIt can support learning in authentic situations, a key element of a professionalization path, approaching the realities experienced by patients, clients, or caregivers.ÉnoncĂ© des implications de la recherche Durant la pandĂ©mie, l’application MapIt a Ă©tĂ© intĂ©grĂ©e dans un programme d’ergothĂ©rapie pour soutenir l’apprentissage Ă  distance de l’adaptation de l’environnement bĂąti. MapIt permet de cartographier des piĂšces d’un domicile, puis d’en gĂ©nĂ©rer un modĂšle en 3D pour la visualisation et la prise de mesures virtuelles. Les Ă©tudiantes expriment que le recours Ă  MapIt durant leur formation mĂšne Ă  incarner les rĂŽles attendus d’une ergothĂ©rapeute. Pour inspirer d’autres bonnes idĂ©es pĂ©dagogiques, cet article prĂ©sente comment MapIt peut soutenir l’apprentissage en situations authentiques, un Ă©lĂ©ment clĂ© d’un parcours de professionnalisation, s’approchant des rĂ©alitĂ©s vĂ©cues par les personnes patientes, clientes ou intervenante
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