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See detailMethods and models for brain connectivity assessment across levels of consciousness
Amico, Enrico ULg

Doctoral thesis (2016)

The human brain is one of the most complex and fascinating systems in nature. In the last decades, two events have boosted the investigation of its functional and structural properties. Firstly, the ... [more ▼]

The human brain is one of the most complex and fascinating systems in nature. In the last decades, two events have boosted the investigation of its functional and structural properties. Firstly, the emergence of novel noninvasive neuroimaging modalities, which helped improving the spatial and temporal resolution of the data collected from in vivo human brains. Secondly, the development of advanced mathematical tools in network science and graph theory, which has recently translated into modeling the human brain as a network, giving rise to the area of research so called Brain Connectivity or Connectomics. In brain network models, nodes correspond to gray-matter regions (based on functional or structural, atlas-based parcellations that constitute a partition), while links or edges correspond either to structural connections as modeled based on white matter fiber-tracts or to the functional coupling between brain regions by computing statistical dependencies between measured brain activity from different nodes. Indeed, the network approach for studying the brain has several advantages: 1) it eases the study of collective behaviors and interactions between regions; 2) allows to map and study quantitative properties of its anatomical pathways; 3) gives measures to quantify integration and segregation of information processes in the brain, and the flow (i.e. the interacting dynamics) between different cortical and sub-cortical regions. The main contribution of my PhD work was indeed to develop and implement new models and methods for brain connectivity assessment in the human brain, having as primary application the analysis of neuroimaging data coming from subjects at different levels of consciousness. I have here applied these methods to investigate changes in levels of consciousness, from normal wakefulness (healthy human brains) or drug-induced unconsciousness (i.e. anesthesia) to pathological (i.e. patients with disorders of consciousness). [less ▲]

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See detailExtremophile plants as source of biopesticides against European damageable plant pathogens
Ben Kaab, Sofiène ULg; Parisi, Olivier ULg; De Clerck, Caroline ULg et al

Poster (2016, September 14)

The use of plant-derived products in postharvest disease management may be a valid alternative to conventional chemical treatments (Pane et al., 2016). Unfavorable environmental conditions (such as salt ... [more ▼]

The use of plant-derived products in postharvest disease management may be a valid alternative to conventional chemical treatments (Pane et al., 2016). Unfavorable environmental conditions (such as salt and drought) increase production and accumulation of reactive oxygen species (ROS). Consequently, extremophile plants have developed adaptive responses including the synthesis of specific bioactive molecules used for medical and nutritional purposes (Ksouri et al., 2012). In that context, the main objective of the present study was the identification of effective plant extracts and essential oils from extremophile plants against the most important plant pathogens in Europe (in term of loss, treatment necessity and/or cost). The study began with the selection of four endemic medicinal species suspected to be antimicrobial due to their wealth of phenolic and terpene compounds, such as flavonoids, phenolic acids, and coumarins (Ksouri et al., 2012). Each of the aerial plant materials was grounded and macerated with solvent (methanol or chloroform) for 24 h. The solvent was then eliminated along rotavapor. The yield of plant extract varied between 1.56 and 6.7%. Kinetics of growth of the 3 pathogens cultivable in liquid medium was determined before testing the impact of plant extracts and essential oils. Methanolic and chloroform plant extracts (EM1, EM2, EC1 and EC2) and essential oils (EO1, EO2) were compared for their antifungal potential. The chemical composition of the essential oils obtained by hydrodistillation from the aerial parts was analyzed by GC/MS. Yield of essential oil varied between 0.7 and 1.2%. Therefore, antifungal activity of plant extracts and essential oils was evaluated using ELISA microplates with a blocked randomized design, as described previously (Parisi et al., 2013). The results obtained showed that EM2 at 7 mg/ml has a very high fungistatic activity against Fusarium culmorum, F. oxysporum and Penicillium italicum. It was characterized with a high amount of polyphenols, flavonoids and condensed tannins. Statistical analysis showed that the efficiency of methanol extracts significantly differed from those of the chloroform extracts. In addition, essential oils significantly reduced spores germination in a dose-dependent manner. Their fungistatic activity reached 100% at 6000 ppm. In conclusion, this work allowed us to open new perspectives on the application of extremophile plant extracts as novel biocontrol strategy against plant pathogens. [less ▲]

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See detailDYNAMIC MODELING OF WASTE HEAT RECOVERY ORGANIC RANKINE CYCLE SYSTEMS IN THE AMESIM PLATFROM
Guillaume, Ludovic ULg; Ameel, Bernd; Criens, Chris et al

Conference (2016, September 14)

ORC waste heat recovery is a very promising technology for reducing fuel consumption and consequently the CO2 emissions of future heavy-duty trucks. Because of the transient nature of the heat sources ... [more ▼]

ORC waste heat recovery is a very promising technology for reducing fuel consumption and consequently the CO2 emissions of future heavy-duty trucks. Because of the transient nature of the heat sources encountered on a truck, dynamic simulations are an essential part of the design process of ORC systems for truck applications. Dynamic models are useful for component design, control design and transient evaluation of ORC systems. To ease the burden of building numerous dynamic models of different candidate ORCs while the design process is ongoing, a library of generic dynamic models of ORCs is built in this work. These models work in synergy with a steady-state ORC design tool in which is added a function to automatically populate the parameters of the dynamic models. In this work, the dynamic model library and their parameterization process in LMS AMESim are described. The platform is largely used in automotive industry and offers a variety of libraries: Engine, Control, Two-Phase Flow, etc. Finally, the dynamic models are compared against the steady-state models and experimental data. [less ▲]

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See detailTHERMO-ECONOMIC OPTIMIZATION OF ORGANIC RANKINE CYCLE SYSTEMS FOR WASTE HEAT RECOVERY FROM EXHAUST AND RECIRCULATED GASES OF HEAVY DUTY TRUCKS
Guillaume, Ludovic ULg; Legros, Arnaud; Lemort, Vincent ULg

Conference (2016, September 14)

Waste heat recovery (WHR) ORC is a very promising technology for reducing fuel consumption and consequently the CO2 emissions of future heavy-duty trucks (HDT). Nonetheless, the adoption of this ... [more ▼]

Waste heat recovery (WHR) ORC is a very promising technology for reducing fuel consumption and consequently the CO2 emissions of future heavy-duty trucks (HDT). Nonetheless, the adoption of this technology in the automotive domain requires specific R&D activities going from the system definition to the on-board integration. This study focuses on the preliminary design phase of ORC systems recovering the heat wasted from two of the sources available on a HDT: the exhaust and recirculated gases. From these heat sources and their combinations, 6 possible architectures are identified. On the other hand, 4 volumetric expansion machine technologies are considered (Scroll, Screw, Piston and Vane Expanders). At the end, 24 topologies are modelled considering only the main components (Pump, Heat exchangers, Expansion machines). A three-step optimization method is proposed to identify the most promising system. First, the most suitable design conditions are identified using a simple model of expansion machine. In a second step, the design phase, using more detailed models for the expansion machines, a thermodynamic and economic optimizations are performed. Finally, in a third step, the output power of the latter system models is maximized in off-design conditions. [less ▲]

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See detailMix and match: Essays on collective dynamics in nascent social entrepreneurship
Dufays, Frédéric ULg

Doctoral thesis (2016)

Social entrepreneurship is increasingly recognized both in research and practice as a form of entrepreneurship that is inherently hybrid as it combines a social-welfare logic with a commercial logic at ... [more ▼]

Social entrepreneurship is increasingly recognized both in research and practice as a form of entrepreneurship that is inherently hybrid as it combines a social-welfare logic with a commercial logic at its core. Collective dynamics, whether they point at an networked individual or a team, appear particularly salient both in the discourse on social entrepreneurship and in its practice. These would constitute a distinguishing feature of social entrepreneurship, which this dissertation examines through a set of four related research papers. First, social entrepreneurship as generically collective is taken as a starting point to review the literature. In particular, it identifies how the social network concept is used in relation to social entrepreneurship and develops research proposals aiming to explain social entrepreneurship emergence through this lens. Considering the entrepreneurial team as a crystallized social network that allows for bridging distinct logics constitutes one of these proposals, which is further explored in the second paper. Grounded in institutional theory, it develops a processual model describing how hybridity emerges and sustains throughout the entrepreneurial process and suggests that the entrepreneurial team may be a carrier of hybridity. The empirical part of the dissertation examines particular moments of this process. The third paper questions the collective dimension by seeking individuals’ meanings of entrepreneuring in team in the context of social entrepreneurship. Located a bit further in time in the entrepreneurial process, the fourth paper looks at organizational tensions in social entrepreneurial teams and nascent social enterprises and seeks to portray the manifestations of hybridity. Overall, this dissertation contributes to institutional theory by exploring the emergence of hybrid organizations; to team entrepreneurship literature by unravelling its antecedents and by explaining tensions in a context of institutional complexity; and to knowledge on social entrepreneurship by examining its collective dynamics at the early stages of the process. [less ▲]

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See detailWhat’s with the hyphens? A social studies perspective on science-technology-society
Van Oudheusden, Michiel ULg

Scientific conference (2016, September 13)

This presentation highlights the roles social scientists (notably in the field of science and technology studies) can/should play in nuclear research and development. Three cases are briefly described and ... [more ▼]

This presentation highlights the roles social scientists (notably in the field of science and technology studies) can/should play in nuclear research and development. Three cases are briefly described and assessed: citizen science after Fukushima, incident reporting at the Belgian Nuclear Research Centre SCK-CEN, and the "microbiologization" of radioactive waste management. [less ▲]

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See detailOrganocatalytic ring-opening polymerization towards polyphosphoesters
Clément, Benoit; Vanslambrouck, Stépanie; Carion, Stéphan ULg et al

Conference (2016, September 13)

Hydrolytically degradable and biocompatible aliphatic polyesters are widely applied for biomedical applications as implants, scaffolds for tissue engineering and, finally, as nanocarriers for drug ... [more ▼]

Hydrolytically degradable and biocompatible aliphatic polyesters are widely applied for biomedical applications as implants, scaffolds for tissue engineering and, finally, as nanocarriers for drug delivery. Aliphatic phophoesters, known since the pioneering work of S. Penczek in the 70’s, exhibit the same properties of hydrolytic degradability and biocompatibility and are thus more and more studied for biomedical applications as well. In the field of materials, anti-fire properties opens up new perspectives. The difference between polyesters and polyphosphoesters in terms of synthesis and properties will be highlighted. Polyphosphosphoesters are synthesized by step-growth and chain growth polymerization. When these polyphosphoesters are synthesized by ring-opening polymerization of cyclic phosphoesters, organocatalysts turned out to be very efficient compared to coodination processes. The last part of the talk will deal with te implementation of ROP of cyclic phosphates towards a series of amphiphilic PEO-block-polyphosphate copolymers of tailored hydrophobicity depending on the length of the lateral alkyl group. These polymers are able to self assemble into nanoparticles by direct dissolution in water, thus in the absernce of any organic solvent. The so-obtained micelles were studied by a set of techniques (Pyrene Fluorescence, Dynamic Light Scattering, Tensiometry). Finally, the influence of the hydrophobicity of the polyphosphate block of the micelle on the encapsulation and the release of a model drug was investigated. [less ▲]

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See detailInvestigating the effect of plant-derived amendments on PAHs degradation in brownfield contaminated soils
Davin, Marie ULg; Starren, Amandine ULg; Colinet, Gilles ULg et al

Conference (2016, September 13)

Polycyclic aromatic hydrocarbons (PAHs) are a class of persistant organic compounds of major concern that tend to accumulate in the environment, damaging ecosystems and health. Brownfields represent an ... [more ▼]

Polycyclic aromatic hydrocarbons (PAHs) are a class of persistant organic compounds of major concern that tend to accumulate in the environment, damaging ecosystems and health. Brownfields represent an important tank for PAHs that require remediation. As an alternative to environmentally aggressive, expensive and often disruptive soil remediation strategies, experiences have been carried on to understand and develop techniques based on bioremediation and phytoremediation. PAHs degradation experiments were conducted in microcosms (laboratory scale) in order to determine whether several plant-derived amendments could enhance bioremediation. Briefly, samples of aged contaminated soils were treated with different concentrations of Medicago sativa or Trifolium pratense root exudates or dried roots, commercial saponin, a natural surfactant found in some plant roots such as some Fabaceae, and some samples were left unamended as controls. Soil samples were incubated for two and four weeks at controlled temperature (28°C). Carbon dioxide emission was monitored throughout the whole incubation. At the end of each experiment, dehydrogenase activity was measured as an indicator of microbiological activity and residual PAHs were determined using High-Performance Liquid Chromatography with Fluorimetric Detection (HPLC-FLD). In total, eleven amendment modalities and two incubation periods were tested and repeated four times. Preliminary experiments show promising results as amended samples seem to show different respiration activities. Ongoing studies will allow discussion as to whether or not PAHs degradation is influenced by the different modalities and if there are any differences according to the nature and concentration of the amendment. [less ▲]

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See detailDynamics of ligands on gold surface to obtain Janus nanoclusters: A theoretical and experimental investigation
Lugo Preciado, Jesús Gustavo ULg

Doctoral thesis (2016)

We performed a joint computational – experimental investigation of the dynamics of ligand exchange on gold nanoclusters (GNC) surface with the aim to understand how to control the structural and optical ... [more ▼]

We performed a joint computational – experimental investigation of the dynamics of ligand exchange on gold nanoclusters (GNC) surface with the aim to understand how to control the structural and optical properties of GNC through the design of their ligand shell. Our computational studies were carried out in the framework of the Kohn – Sham implementation of density functional theory in quantum chemistry. We analyzed the main features of UV – Vis spectra computed at the TD – DFT / CAM – B3LYP level for the Au13, Au25, and Au28 metallic cores protected by thiolate, chloride, and phosphine ligands. Our results show that it is possible to tune the energy of the lowest absorption band of gold clusters by ligand shell engineering in order to control the charge redistribution between ligand shell and metallic core. In parallel we synthesized a set of Au25(ATP)x(TP)18 – x clusters with different ATP/TP ratios using an adapted Demessence protocol by combining 4ATP (4 – aminothiophenol) and TP (thiophenol) ligands. ESI – MS measurements evidence that for these mixed ligand shells the Au25 nuclearity is preserved. However, the addition of the DDT (1 – dodecanethiol) ligand in the mixture leads to nanoparticle formation. FT – IR spectroscopy confirms the absorption of two different ligands on the gold surface and SAXS shows that we have a good correlation between the distance between two clusters and the length of the ligand protecting them. Furthermore, we collaborated with the Institut Charles Gerhardt in the Université de Montpellier, France whose experimental results show that several n – heterocyclic carbenes (NHC) bearing different groups on the N atoms exhibit similar reactivity when protecting a gold nanosurface. The formation of the bis(NHC) AuI gold complexes is evidenced by 13C NMR. In order to complement and interpret the experimental results, we carried out a computational study of the adsorption of a single NHC on Au38 which acts as a model for the gold surface, as well as of the fully NHC ligated Au38 cluster. The joint experimental – theoretical study, in particular the comparison between computed and 13C NMR spectra allows proposing a possible mechanism explaining the formation of [NHC – Au – NHC]+ complexes and the erosion experienced by the nanoparticle. Finally, we carried out a comparison of the mode of binding and the structural and optical properties of the fully ligated PH3 and NHC GNC with metallic cores of different nuclearities. Our computations show that the Au – P bond is weaker than the Au – NHC one. Additionally, our study confirms that the ligand – to – metal charge transfer is an important parameter for understanding the electronic transitions and the UV – Vis spectra in these clusters. Our computations on the PH3 – Au38 set of complexes show that there is a site selectivity for the reactivity for the PH3 interacting on the Au38 surface which allows predicting where the PH3 is likely to be adsorbed. This selectivity is not observed in the case of the binding of a single NHC ligand on the surface of the Au38 cluster. [less ▲]

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See detailUn demi-siècle d''exploration de la planète Mars
Stiepen, Arnaud ULg

Conference given outside the academic context (2016)

Detailed reference viewed: 13 (0 ULg)
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See detailEffects of equine chorionic gonadotropin (eCG) on the sexual behaviour and ovulatory characteristics of female african N'Dama cattle.
Okouyi, M.W. Marcel; Hanzen, Christian ULg

in Revue de Médecine Vétérinaire (2016), 167(7-8), 211-215

This paper evaluated the effects of eCG on the characteristics of oestrus and ovulation after heifers and cows had been synchronised following vaginal administration of progesterone for seven days ... [more ▼]

This paper evaluated the effects of eCG on the characteristics of oestrus and ovulation after heifers and cows had been synchronised following vaginal administration of progesterone for seven days (Controlled Internal Drug Released) and a PGF2α injection two days after the end of treatment. The animals were randomly split into a non-treated control group (n=26) and four groups with increasing doses of eCG: 300 IU (n=25), 400 IU (n=24), 500 IU (n=23) and 600 IU (n=23), which were injected on the day of CIDR withdrawal. The animals were then followed (24 hours a day) for six days. Oestrus was confirmed on the basis of identifying 'standing oestrus', i.e., when the cow stood to be mounted. Seven to ten days after the CIDR® was withdrawn, the animals were slaughtered, and their ovaries were examined to identify and count the number of follicular and/or luteal structures. The onset of heat was 48.6 ± 5.3 hours after eCG injection, and the average length of oestrus was 9.9 ± 2 hours. The eCG dosage had no significant effect on these two parameters. In contrast, the observed rate of oestrus was significantly (p<0.05) higher in animals that had been treated (70.8 to 84.0%) in comparison with animals that had not been treated (50%). Similarly, the ovulation rate was significantly (p<0.05) higher in treated animals (88.0 to 100%) than in untreated animals (73.1%). The percentage of animals that presented multiple ovulations increased significantly (p <0.001) with the dosage of eCG administered (4.5% to 36.4%). [less ▲]

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See detailCaractérisation multiscalaire de contaminations en éléments traces dans les sols : distribution spatiale et verticale, évaluation du transfert sol-plante-vers de terre et gestion potentielle par amendements organiques
Liénard, Amandine ULg

Doctoral thesis (2016)

Human economic and technological development has a negative impact on the environment. The soil is not spared from this growing threat through its role in the environmental interface. Once degraded as a ... [more ▼]

Human economic and technological development has a negative impact on the environment. The soil is not spared from this growing threat through its role in the environmental interface. Once degraded as a result of contamination, it can no longer fulfill its ecosystem functions such as the protection of ecosystems, food production or preservation of the quality of surface water and groundwater. The studies presented in the thesis are on soil contaminated by atmospheric fallouts enriched by trace elements. This type of contamination increases the natural levels of contaminants in soils and particularly in surface horizons to exceed the maximum levels set by legislation. The first axe of research concerns the assessment of contamination at a landscape scale around a former zinc-lead ore-treatment plant. The spatial distribution of cadmium, lead and zinc in the topsoil (0-20 cm) was characterized using 247 samples taken in crop, grassland and forest on three major types of loam soils representative of the study area Sclaigneaux (Wallonia, Belgium). The distribution of contaminants is explained by the distance to the source of contamination, direction of dominant winds, land use and soil type. Subsequently, 22 soil profiles were sampled within the study area to estimate the vertical transfer of contaminants. Based on various indexes of contamination, no migration along the profiles has been demonstrated. Only some more clay horizons presented contaminant levels that increased relative to their upper horizons. The second approach studied the soil-plant transfer and soil-plant-worm transfer of contaminants. First, a field study of the quality of grains of barley (Hordeum vulgare L.) harvested in the study area Sclaigneaux was performed. It appears that the concentration of cadmium in the grain meets quality standards for placing the cereals on the market. However, 78% and 94% of zinc and cadmium, respectively, concentrations measured in grains exceed the expected levels of a non-impacted environment by human activity. Secondly, a study on microcosms was conducted with soils of agricultural parcels around Sclaigneaux on which two crops (faba bean, Vicia faba L. and corn, Zea mays L.) were grown and where earthworms (Eisenia fetida (Savigny)) were introduced. The life traits of E. fetida such as mortality and adult weight were not affected by the levels of contaminants unlike the presence of plants which limit their reproduction (weight and number of cocoons). Moreover, the presence of E. fetida in microcosms influenced the mobility and bioavailability of contaminants. The third approach deals with metal contaminations in vegetable gardens and their management using organic amendments. This method of stabilization aims to decrease the labile fraction of soil contaminants and further reduce their transfer to plants. To do so, two vegetables (spinach, Spinacia oleracea L. and lettuce, Lactuca sativa L.) were grown on contaminated garden soils enriched in various amendments sold in garden centers. The major finding of this study is that management by amendments does not allow a systematic decrease in the soluble fraction contaminants. This is mainly due to the direct intake of rapidly mobilized trace elements produced by the addition of some of the studied amendments. [less ▲]

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See detailRaised interferon beta, type 3 interferon and interferon stimulated genes - evidence of innate immune activation in neutrophilic asthma.
da Silva, J.; Hilzendeger, Clarissa ULg; Moermans, Catherine et al

in Clinical & Experimental Allergy : Journal of the British Society for Allergy & Clinical Immunology (2016)

BACKGROUND: Interferons play an important role in innate immunity. Previous studies report deficiency in virus-induction of interferon (IFN)-alpha, -beta and -lambda in bronchial epithelial and bronchial ... [more ▼]

BACKGROUND: Interferons play an important role in innate immunity. Previous studies report deficiency in virus-induction of interferon (IFN)-alpha, -beta and -lambda in bronchial epithelial and bronchial lavage cells in atopic asthmatics. It is now recognized that asthma is a heterogeneous disease comprising different inflammatory phenotypes, some of which may involve innate immune activation in the absence of overt infection. OBJECTIVE: The aim of the study was investigate if the severity of asthma or a specific cellular sputum pattern may be linked to evidence of innate immune activation. METHODS: Here we investigate the expression of IFN-beta, IFN-lambda1 (IL-29), IFN-lambda2/3 (IL-28A/B) and the interferon-stimulated genes (ISGs) myxovirus resistance 1 (Mx1), oligoadenylate synthetase (OAS) and viperin in unstimulated sputum cells in 57 asthmatics (including 16 mild, 19 moderate and 22 severe asthma patients) and compared them with 19 healthy subjects. RESULTS: We observed increased expression of IFN-beta, IFN-lambda1/IL-29, OAS and viperin in asthmatic compared to healthy subjects while IL-28 was not expressed in any group. The overexpression was restricted to neutrophilic asthmatics (sputum neutrophils >/= 76%) while eosinophilic asthmatics (sputum eosinophils >/= 3%) did not differ from healthy subjects or even showed a lower expression of Mx1. No difference in interferon or ISG expression was seen according to clinical asthma severity. CONCLUSION AND CLINICAL RELEVANCE: Neutrophilic, but not eosinophilic, asthmatics display overexpression of IFN-beta, IFN-lambda1/IL-29 and ISGs in their sputum cells that may reflect ongoing innate immune activation. This article is protected by copyright. All rights reserved. [less ▲]

See detailSynthesis and characterizations of non-isocyanate polyurethane (NIPU) hydrogels
Gennen, Sandro ULg; Grignard, Bruno ULg; Thomassin, Jean-Michel ULg et al

Poster (2016, September 12)

Polyurethane (PU) is on of the most used polymers for the preparation of hydrogels due to its good biocompatibility, biodegradation and excellent mechanical properties. PU hydrogels are found in lot of ... [more ▼]

Polyurethane (PU) is on of the most used polymers for the preparation of hydrogels due to its good biocompatibility, biodegradation and excellent mechanical properties. PU hydrogels are found in lot of applications such as wound dressing, soft contact lenses, drug delivery and scaffolds for tissue engineering. Classicaly, PU is produced by a step-growth polymerization between diols and diisocyanates. However, in order to avoid the use of harmful isocyanates compounds and because of regulations which tend to ban the use of isocyanates, we developed hydrogels based on a non-isocyanate polyurethane (NIPU) chemistry by valorizing CO2-sourced cyclic carbonates and amines. Precisely, NIPU hydrogels were prepared by a solvent-free copolymerization between bifunctional hydrophilic polyethylene glycol cyclic carbonates and diamines in presence of a triamine as a crosslinker, followed by a water swelling of the obtained cross-linked gel. Parameters such as the cross-linking ratio and diamine’s nature were optimized. Different clay contents (cloiste 30B) as nanofiller were dispersed in the ideal cyclic carbonate/diamine/triamine formulation prior polymerization in order to reinforce the compression properties of NIPU hydrogels. Finaly, we were able to prepare NIPU hydrogels with water content up to 80 % and good compression properties using low clay content. [less ▲]

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See detailPolyphosphoester containing amphiphilic block copolymers as drug nanocarriers
Ergül, Zeynep ULg; Vanslambrouck, Stéphanie; Thiry, Justine ULg et al

Poster (2016, September 12)

The design of drug delivery systems often requires biodegradable and biocompatible materials that allow safe retention and controlled release of the drug. In this respect, supramolecularly self-assembled ... [more ▼]

The design of drug delivery systems often requires biodegradable and biocompatible materials that allow safe retention and controlled release of the drug. In this respect, supramolecularly self-assembled amphiphilic block copolymers into spherical micelles are appropriate carriers for poorly soluble drugs. In that framework, we have designed novel functional poly(ethylene oxide)-b-polyphosphoester amphiphilic block copolymers able to cross-linked under UV and degrade in response to a reduction of the pH from neutral conditions. Therefore, an unsaturated alkene side-chain was introduced on the cyclic phosphate monomer according to a one-step reaction followed by its organocatalyzed polymerization initiated by a poly(ethylene oxide) macroinitiator. After self-assembly into water, the micelles were cross-linked by UV irradiation. Then, these cross-linked micelles have been loaded by doxorubicin, i.e. a drug used in cancer therapy. We observed that the doxorubicin loading increased with the number of double bonds on the polyphosphate block of non-cross-linked micelles. This diblock amphiphilic copolymer bearing pendant unsaturations appears thus particularly promising candidate to build micellar drug delivery systems for intravenous injection. [less ▲]

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See detailOverhanging Constraints in Addivitive Manufacturing Using Two Different Tools
Bauduin, Simon ULg; Collet, Maxime ULg; Duysinx, Pierre ULg

Conference (2016, September 12)

Topology optimization is widely used as a design tool for advanced application in mechanical, aerospace and automotive industries. This technique offers an optimal distribution of a predetermined amount ... [more ▼]

Topology optimization is widely used as a design tool for advanced application in mechanical, aerospace and automotive industries. This technique offers an optimal distribution of a predetermined amount of material in a given design space. In the last years, a lot of efforts has been invested into the development of high performance methods such as homogenization, SIMP or BESO. However as the state of the art in manufacturing experiences evolution, a coupling between topology optimization and additive manufacturing is needed. Additive manufacturing has numerous advantages that fits the characteristics of topology optimized designs. It can manufacture highly complex design without high cost increase and furthermore continuous density material of the SIMP method could be manufactured by lattice structures. With all the opportunities given by the additive manufacturing the urge to bind the last one to topology optimization is heavily required. Specific constraints related to manufacturing issues have to be taken into account such as the need of supports structures to ensure a good heat evacuation during the manufacturing process, as well as to hold up overhanging section. Some researches have been done to try to include this constraint in the optimization problem such as Leary and al or Andrew T. Gaynor. However this work focuses on 2 different methods (projection scheme and mechanical approach) to tackle the overhanging problem and compare them . [less ▲]

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See detailOrganocobalt complexes as source of radicals for the controlled polymerization of unconjugated monomers
Demarteau, Jérémy ULg; Cordella, Daniela ULg; Kermagoret, Anthony et al

Poster (2016, September 12)

Detailed reference viewed: 11 (2 ULg)