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Document Server@UHasselt (58.026 recursos)

Repository of the University of Hasselt containing publications in the fields of statistics, computer science, information strategies and material from the Institute for behavioural sciences.

Applied and Analytical Chemistry

Mostrando recursos 1 - 20 de 181

  1. Exploring the rhizospheric and endophytic bacterial communities of Acer pseudoplatanus growing on a TNT-contaminated soil: towards the development of a rhizocompetent TNT-detoxifying plant growth promoting consortium

    THIJS, Sofie; Van Dillewijn, Pieter; SILLEN, Wouter; TRUYENS, Sascha; HOLTAPPELS, Michelle; D'HAEN, Jan; CARLEER, Robert; WEYENS, Nele; AMELOOT, Marcel; Ramos, Juan-Luis; VANGRONSVELD, Jaco
    Background and aims Numerous microorganisms have been isolated from trinitrotoluene (TNT)-contaminated soils, however TNT tends to persist, indicating that the microbial biomass or activity is insufficient for degradation. Deep-rooting trees at military sites have been found to take-up contaminants from groundwater, and the extensive root and endosphere provide ideal niches for microbial TNT-transformations. Methods We characterised the rhizosphere, root endosphere and endo-phyllosphere bacteria of Acer pseudoplatanus growing at a historically TNT-contaminated location, using 16S rRNA gene fingerprinting, bacteria isolation, oxidoreductase gene-cloning, in planta growth-promotion (PGP) tests, inoculation, plant physiology measurements and microscopy. Results Based on terminal-restriction-fragment-length-polymorphism analysis, bulk soil and...

  2. Evaluation of the Thickness and Oxygen Transmission Rate before and after Thermoforming Mono- and Multi-layer Sheets into Trays with Variable Depth

    BUNTINX, Mieke; WILLEMS, Gert; KNOCKAERT, Griet; Adons, Dimitri; YPERMAN, Jan; CARLEER, Robert; PEETERS, Roos
    During thermoforming, plastic sheets are heated and subsequently deformed through the application of mechanical stretching and/or pressure. This process directly impacts sheet properties such as material thickness in walls, corners, and bottom, crystallinity in the constituent layers, and particularly the oxygen gas permeability. The aim of this study was to quantify the impact of thermoforming on thickness and oxygen transmission rate (OTR) of selected packaging materials (polypropylene (PP); PP/ethylene-vinyl alcohol co-polymer/PP (PP/EVOH/PP); polystyrene/EVOH/polyethylene (PS/EVOH/PE); amorphous polyethylene terephtalate/PE (APET/PE); APET/PE/EVOH/PE; polyamide/PE (PA/PE); and (PE/)PA/EVOH/PA/PE). These materials were extruded in two different thicknesses and thermoformed into trays with the same top dimensions...

  3. Factors Influencing the Conductivity of Aqueous Sol(ution)-Gel-Processed Al-Doped ZnO Films

    DAMM, Hanne; ADRIAENSENS, Peter; DE DOBBELAERE, Christopher; Capon, Boris; ELEN, Ken; DRIJKONINGEN, Jeroen; CONINGS, Bert; MANCA, Jean; D'HAEN, Jan; Detavernier, Christophe; Magusin, Pieter C. M. M.; Hadermann, Joke; HARDY, An; VAN BAEL, Marlies
    Solution processing of Al-doped ZnO (AZO) is interesting from an economical point of view for reducing synthesis and deposition costs in comparison to that for vacuum methods. Several (aqueous) chemical solution deposition routes have been explored for AZO, but the question that has never been answered is how state-of-the-art conductivity is achieved. Here, we fine tune an aqueous solution precursor for AZO, resulting in resistivities within the 10???3 Ohm cm range after a reductive treatment. Profound insights are gained through the study of the density of the film, the crystal phase, the optimum Al doping, and the effect of Al...

  4. Differential response of Arabidopsis leaves and roots to cadmium: Glutathione-related chelating capacity vs antioxidant capacity

    JOZEFCZAK, Marijke; KEUNEN, Els; Schat, Henk; Bliek, Mattijs; Hernandez, Luis E.; CARLEER, Robert; REMANS, Tony; BOHLER, Sacha; VANGRONSVELD, Jaco; CUYPERS, Ann
    This study aims to uncover the spatiotemporal involvement of glutathione (GSH) in two major mechanisms of cadmium (Cd)-induced detoxification (i.e. chelation and antioxidative defence). A kinetic study was conducted on hydroponically grown Arabidopsis thaliana (L Heyhn) to gain insight into the early events after exposure to Cd. Cadmium detoxification was investigated at different levels, including gene transcripts, enzyme activities and metabolite content. Data indicate a time-dependent response both within roots and between plant organs. Early on in roots, GSH was preferentially allocated to phytochelatin (PC) synthesis destined for Cd chelation. This led to decreased GSH levels, without alternative pathways activated...

  5. Valorisatie van varkensmest door pyrolyse - Cleantech business case in Limburg

    KUPPENS, Tom; MAGGEN, Jens; CARLEER, Robert; YPERMAN, Jan; VAN DAEL, Miet; VAN PASSEL, Steven
    i-Cleantech Vlaanderen

  6. Factors Influencing the Conductivity of Aqueous Sol(ution)−Gel- Processed Al-Doped ZnO Films

    DAMM, Hanne; Adriaensens, P.; De Dobbelaere, Christopher; Capon, Boris; ELEN, Ken; DRIJKONINGEN, Jeroen; CONINGS, Bert; MANCA, Jean; D'Haen, Jan; Detavernier, Christophe; Magusin, Pieter C. M. M.; Hadermann, Joke; HARDY, An; VAN BAEL, Marlies
    Solution processing of Al-doped ZnO (AZO) is interesting from an economical point of view for reducing synthesis and deposition costs in comparison to that for vacuum methods. Several (aqueous) chemical solution deposition routes have been explored for AZO, but the question that has never been answered is how state-of-the-art conductivity is achieved. Here, we fine tune an aqueous solution precursor for AZO, resulting in resistivities within the 10−3 Ohm cm range after a reductive treatment. Profound insights are gained through the study of the density of the film, the crystal phase, the optimum Al doping, and the effect of Al...

  7. Formulation of itraconazole nanococrystals and evaluation of their bioavailability in dogs

    De Smet, Lieselotte; Saerens, Lien; De Beer, Thomas; CARLEER, Robert; ADRIAENSENS, Peter; Van Bocxlaer, Jan; Vervaet, Chris; Remon, Jean Paul
    The aim of the study is to increase the bioavailability of itraconazole (ITRA) using nanosized cocrystals prepared via wet milling of ITRA in combination with dicarboxylic acids. Wet milling was used in order to create a nanosuspension of ITRA in combination with dicarboxylic acids. After spray-drying and bead layering, solid state was characterized by MDSC, XRD, Raman and FT-IR. The release profiles and bioavailability of the nanococrystalline suspension, the spray-dried and bead layered formulation were evaluated. A monodisperse nanosuspension (549 +/- 51 nm) of ITRA was developed using adipic acid and Tween (R) 80. Solid state characterization indicated the formation...

  8. Electronic Structure of the Positive Radical of C-13-Labeled Poly(3-Octylthienylene Vinylene) Polymer

    Ling, Yun; DILIEN, Hanne; VANDERZANDE, Dirk; ADRIAENSENS, Peter; VAN DOORSLAER, Sabine
    Poly(3-octylthienylene vinylene) (O-PTV) has a great potential as low-bandgap p-type semiconductor for photovoltaic applications. Here, the positive radical state (positive polaron) is induced chemically in the O-PTV polymer in which the vinylene sites are selectively C-13-labeled. Using multi-frequency continuous wave and pulsed electron paramagnetic resonance, the g tensor and maximum H-1 and C-13 hyperfine couplings are determined. A comparative density functional theory (DFT) analysis of PTV-like oligomers is performed. The experimental parameters suggest a larger localization of the positive polaron than follows from the DFT analysis. The counter anion may play a crucial role in localizing the polaron.

  9. Bacteria associated with yellow lupine grown on a metal-contaminated soil: in vitro screening and in vivo evaluation for their potential to enhance Cd phytoextraction

    WEYENS, Nele; GIELEN, Marijke; BECKERS, Bram; BOULET, Jana; VAN DER LELIE, Daniel; Taghavi, S.; CARLEER, Robert; VANGRONSVELD, Jaco
    In order to stimulate selection for plant-associated bacteria with the potential to improve Cd phytoextraction, yellow lupine plants were grown on a metal-contaminated field soil. It was hypothesised that growing these plants on this contaminated soil, which is a source of bacteria possessing different traits to cope with Cd, could enhance colonisation of lupine with potential plant-associated bacteria that could then be inoculated in Cd-exposed plants to reduce Cd phytotoxicity and enhance Cd uptake. All cultivable bacteria from rhizosphere, root and stem were isolated and genotypically and phenotypically characterised. Many of the rhizobacteria and root endophytes produce siderophores, organic acids,...

  10. LINGUISTIC CORRECTION EVALUATION OF 1H-NMR SPECTROSCOPY IN PREDICTING PLATINE-RELATED TOXICITIES IN LUNG CANCER PATIENTS

    VANHOVE, Karolien; MESOTTEN, Liesbet; THOMEER, Michiel; Louis, Evelyne; ADRIAENSENS, Peter

  11. Possible morphological substrates in the pathogenesis of rheumatoid arthritis in human finger joints

    VAN ZWIETEN, Koos Jaap; LAMBRICHTS, Ivo; DE BAKKER, Bernadette; KOSTEN, Lauren; DE MUNTER, Stephanie; GERVOIS, Pascal; ADRIAENSENS, Peter; SCHMIDT, Klaus; HELDER, Paul; LIPPENS, Peter
    In conclusion, we state that curiosity-driven research after normal synovial folds within the PIP-joint of the finger confirms their actual location. Neurovascular bundles in the normal PIP-joint???s capsule, and neurons in lamellated corpuscles within the Proper Collateral Ligament, may shed new light on the pathogenesis of rheumatoid arthritis in human finger joints.

  12. Geochemical study of maltenes from coal biodesulphurisation

    GONSALVESH, Lenia-Nezaet; STEFANOVA, Maia; Marinov, S. P.; CARLEER, Robert; YPERMAN, Jan
    The aim of the study is to examine by geochemical proxies the effect of biodesulphurisation on coal organic matter composition. Two Bulgarian and one Turkish low rank coals (R-r = 0.20-0.46%) were analysed. Prior to biotreatments, the coals were demineralised and depyritised. The white rot fungi Phanerochaete chrysosporium - ME446 and the thermophilic and acidophilic archae Sulfolobus solfataricus - ATCC 35091 were used. After desulphurisations the samples were extracted with chloroform to recover bitumens. Maltenes (portion soluble in n-hexane) were prepared after asphaltenes precipitation. They were fractionated into aliphatic, aromatic and polar fractions and the first two were GC/MS studied....

  13. Aqueous citrato-oxovanadate(IV) precursor solutions for VO2: synthesis, spectroscopic investigation and thermal analysis

    PEYS, Nick; ADRIAENSENS, Peter; VAN DOORSLAER, Sabine; GIELIS, Sven; PEETERS, Ellen; DE DOBBELAERE, Christopher; De Gendt, Stefan; HARDY, An; VAN BAEL, Marlies
    An aqueous precursor solution, containing citrato-VO2+ complexes, is synthesized for the formation of monoclinic VO2. With regard to the decomposition of the VO2+ complexes towards vanadium oxide formation, it is important to gain insights into the chemical structure and transformations of the precursor during synthesis and thermal treatment. Hence, the conversion of the cyclic [V4O12](4-) ion to the VO2+ ion in aqueous solution, using oxalic acid as an acidifier and a reducing agent, is studied by (51)Vanadium nuclear magnetic resonance spectroscopy. The citrate complexation of this VO2+ ion and the differentiation between a solution containing citrato-oxalato-VO2+ and citrato-VO2+ complexes are...

  14. Aqueous citrato-oxovanadate(IV) precursor solutions for VO2: synthesis, spectroscopic investigation and thermal analysis

    PEYS, Nick; ADRIAENSENS, Peter; VAN DOORSLAER, Sabine; GIELIS, Sven; PEETERS, Ellen; DE DOBBELAERE, Christopher; De Gendt, Stefan; HARDY, An; VAN BAEL, Marlies
    An aqueous precursor solution, containing citrato-VO2+ complexes, is synthesized for the formation of monoclinic VO2. With regard to the decomposition of the VO2+ complexes towards vanadium oxide formation, it is important to gain insights into the chemical structure and transformations of the precursor during synthesis and thermal treatment. Hence, the conversion of the cyclic [V4O12](4-) ion to the VO2+ ion in aqueous solution, using oxalic acid as an acidifier and a reducing agent, is studied by (51)Vanadium nuclear magnetic resonance spectroscopy. The citrate complexation of this VO2+ ion and the differentiation between a solution containing citrato-oxalato-VO2+ and citrato-VO2+ complexes are...

  15. Development and characterization of mucoadhesive chitosan films for ophthalmic delivery of cyclosporine A

    Hermans, Kris; Van den Plas, Dave; Kerimova, Sabina; CARLEER, Robert; ADRIAENSENS, Peter; Weyenberg, Wim; Ludwig, Annick
    Ocular chitosan films were prepared in order to prolong ocular delivery of cyclosporine A. The mucoadhesive films were prepared using the solvent casting evaporation method. A 24 full factorial design was used to evaluate the effect of 4 preparation parameters on the film thickness, swelling index and mechanical properties. Moreover, uniformity of content and in vitro drug release were investigated. Possible interactions between the film excipients were studied by FTIR analysis. In vitro experiments were performed in order to evaluate the cytotoxicity and anti-inflammatory activity of the chitosan films. Film thickness, water uptake, mechanical properties and in vitro release of...

  16. The Potential of the Ni-Resistant TCE-Degrading Pseudomonas putida W619-TCE to Reduce Phytotoxicity and Improve Phytoremediation Efficiency of Poplar Cuttings on A Ni-TCE Co-Contamination

    WEYENS, Nele; BECKERS, Bram; SCHELLINGEN, Kerim; VAN DER LELIE, Daniel; Newman, Lee; Ceulemans, Reinhart; CARLEER, Robert; VANGRONSVELD, Jaco; Taghavi, Safiyh
    To examine the potential of Pseudomonas putida W619-TCE to improve phytoremediation of Ni-TCE co-contamination, the effects of inoculation of a Ni-resistant, TCE-degrading root endophyte on Ni-TCE phytotoxicity, Ni uptake and trichloroethylene (TCE) degradation of Ni-TCE-exposed poplar cuttings are evaluated. After inoculation with P. putida W619-TCE, root weight of non-exposed poplar cuttings significantly increased. Further, inoculation induced a mitigation of the Ni-TCE phytotoxicity, which was illustrated by a diminished exposure-induced increase in activity of antioxidative enzymes. Considering phytoremediation efficiency, inoculation with P. putida W619-TCE resulted in a 45% increased Ni uptake in roots as well as a slightly significant reduction in...

  17. Tracking of myelin-reactive T cells in Experimental Autoimmune Encephalomyelitis (EAE) animals using small particles of iron oxide and MRI

    Baeten, Kurt; Adriaensens Peter; Hendriks, Jerome; Theunissen, Evi; Gelan, Jan; Hellings, Niels; Stinissen, Piet
    Myelin-reactive T cells are responsible for initiating the cascade of autoreactive immune responses leading to the development of multiple sclerosis. For better insights into the disease mechanism, it is of major importance to have knowledge on the sites at which these cells are active during disease progression. Herein, we investigated the feasibility of tracking myelin-reactive T cells, upon labelled with SPIO particles, in the central nervous system (CNS) of experimental autoimmune encephalomyelitis (EAE) animals by MRI. First, we determined the optimal labelling condition leading to a high particle uptake and minimal SPIO-Poly-l-lysine (PLL) aggregate formation using Prussian blue staining and...

  18. Valorization of raspberry seed cake by flash and slow pyrolysis: Product yield and characterization of the liquid and solid fraction

    SMETS, Koen; SCHREURS, Sonja; CARLEER, Robert; YPERMAN, Jan
    The valorization of raspberry seed cake by flash and slow pyrolysis is investigated in this study. During flash pyrolysis, temperature significantly affects the yield and properties of the products. The highest liquid yield (53.6 wt%) is found at 450 degrees C. This liquid has a water content (26.2 wt%), a HHV (18.6 MJ/kg) and a pH-value (3.2) that are comparable to those of pyrolysis liquids produced by flash pyrolysis of lignocellulosic biomass. In terms of added-value chemicals, levoglucosan and phenols are interesting compounds because of their high economic value. The solid residue has potential as solid energy carrier at industrial...

  19. Electronic structure of positive and negative polarons in functionalized dithienylthiazolo-[5,4-d]thiazoles: a combined EPR and DFT study

    Ling, Yun; VAN MIERLOO, Sarah; Schnegg, Alexander; Fehr, Matthias; ADRIAENSENS, Peter; LUTSEN, Laurence; VANDERZANDE, Dirk; MAES, Wouter; Goovaerts, Etienne; VAN DOORSLAER, Sabine
    2,5-Dithienylthiazolo[5,4-d]thiazole (DTTzTz) derivatives have high potential for solution-processed organic field-effect transistors and solar cells, both as electron acceptors and donors. Here, the electronic structure of positive and negative radicals (polarons) of two functionalized DTTzTz materials is studied using multi-frequency and multi-resonance electron paramagnetic resonance (EPR) in combination with density functional theory (DFT). It is shown that the negative and positive DTTzTz polarons can be distinguished on the basis of their characteristic EPR parameters. The chemically induced polarons are compared to light-generated states observed in a blend of one of the DTTzTz derivatives with a donor polymer. The study gives in-depth...

  20. Activated carbon from pyrolysis of brewer's spent grain: Production and adsorption properties

    VANREPPELEN, Kenny; VANDERHEYDEN, Sara; KUPPENS, Tom; SCHREURS, Sonja; YPERMAN, Jan; CARLEER, Robert
    Brewer???s spent grain is a low cost residue generated by the brewing industry. Its chemical composition (high nitrogen content 4.35 wt.%, fibres, etc.) makes it very useful for the production of added value in situ nitrogenised activated carbon. The composition of brewer???s spent grain revealed high amounts of cellulose (20.8 wt.%), hemicellulose (48.78 wt.%) and lignin (11.3 wt.%). The fat, ethanol extractives and ash accounted for 8.17 wt.%, 4.7 wt.% and 3.2 wt.%, respectively. Different activated carbons were produced in a lab-scale pyrolysis/activation reactor by applying several heat and steam activation profiles on brewer???s spent grain. Activated carbon yields from...

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