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Document Server@UHasselt (59.068 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.


Mostrando recursos 1 - 20 de 405

  1. Management of the Cardiorenal Syndrome in Decompensated Heart Failure

    VERBRUGGE, Frederik; GRIETEN, Lars; MULLENS, Wilfried
    Background: The management of the cardiorenal syndrome (CRS) in decompensated heart failure (HF) is challenging, with high-quality evidence lacking. Summary: The pathophysiology of CRS in decompensated HF is complex, with glomerular filtration rate (GFR) and urine output representing different aspects of kidney function. GFR depends on structural factors (number of functional nephrons and integrity of the glomerular membrane) versus hemodynamic alterations (volume status, renal perfusion, arterial blood pressure, central venous pressure or intra-abdominal pressure) and neurohumoral activation. In contrast, urine output and volume homeostasis are mainly a function of the renal tubules. Treatment of CRS in decompensated HF patients should...

  2. Implementation of transmural disease management in patients admitted with advanced heart failure

    Duchenne, Jurgen; VERBRUGGE, Frederik; DUPONT, Matthias; Vercammen, Jan; Jacobs, Linda; GRIETEN, Lars; VANDERVOORT, Pieter; MULLENS, Wilfried
    Objective The objective of this study was to assess the feasibility and impact on readmissions of transmural disease management across the borders of the cardiology department in patients with advanced heart failure (HF). Methods and results Consecutive patients, readmitted within one year for advanced HF by a dedicated specialist (n = 55), were followed for 22 10 months after implementation of a hospitalwide transmural disease management strategy. Participants received a tag in their electronic medical record, triggering a HF caregiver contact, with subsequent guideline-recommended, protocol-driven care on each cardiac or non-cardiac hospitalization as well as outpatient evaluation. Upon transition to...

  3. Large improvement of phosphorus incorporation efficiency in n-type chemical vapor deposition of diamond

    Ohtani, Ryota; Yamamoto, Takashi; JANSSENS, Stoffel; Yamasaki, Satoshi; Koizumi, Satoshi
    Microwave plasma enhanced chemical vapor deposition is a promising way to generate n-type, e.g., phosphorus-doped, diamond layers for the fabrication of electronic components, which can operate at extreme conditions. However, a deeper understanding of the doping process is lacking and low phosphorus incorporation efficiencies are generally observed. In this work, it is shown that systematically changing the internal design of a non-commercial chemical vapor deposition chamber, used to grow diamond layers, leads to a large increase of the phosphorus doping efficiency in diamond, produced in this device, without compromising its electronic properties. Compared to the initial reactor design, the doping...

  4. Visible-light sensitization of boron-doped nanocrystalline diamond through non-covalent surface modification

    Krysova, Hana; Vlckova-Zivcova, Zuzana; Barton, Jan; Petrak, Vaclav; NESLADEK, Milos; Cigler, Petr; Kavan, Ladislav
    A novel simple and versatile synthetic strategy is developed for the surface modification of boron-doped diamond. In a two-step procedure, polyethyleneimine is adsorbed on the hydrogenated diamond surface and subsequently modified with a model light-harvesting donor-pi-bridge-acceptor molecule (coded P1). The sensitized diamond exhibits stable cathodic photocurrents under visible-light illumination in aqueous electrolyte solution with dimethylviologen serving as an electron mediator. In spite of the simplicity of the surface sensitization protocol, the photoelectrochemical performance is similar to or better than that of other sensitized diamond electrodes which were reported in previous studies (2008-2014).

  5. An application of field-effect sensors for in-situ monitoring of degradation of biopolymers

    Schusser, S.; Poghossian, A.; Baecker, M.; Krischer, M.; Leinhos, M.; WAGNER, Patrick; Schoening, M. J.
    The characterization of the degradation kinetics of biodegradable polymers is mandatory with regard to their proper application. In the present work, polymer-modified electrolyte-insulator-semiconductor (PMEIS) field-effect sensors have been applied for in-situ monitoring of the pH-dependent degradation kinetics of the commercially available biopolymer poly(D,L-lactic acid) (PDLLA) in buffer solutions from pH 3 to pH 13. PDLLA films of 500 nm thickness were deposited on the surface of an Al-p-Si-SiO2-Ta2O5 structure from a polymer solution by means of spin-coating method. The PMEIS sensor is, in principle, capable to detect any changes in bulk, surface and interface properties of the polymer induced by...

  6. Universal theory of efficiency fluctuations

    Verley, Gatien; WILLAERT, Tim; VAN DEN BROECK, Christian; Esposito, Massimiliano
    Using the fluctuation theorem supplemented with geometric arguments, we derive universal features of the (long-time) efficiency fluctuations for thermal and isothermal machines operating under steady or periodic driving, close or far from equilibrium. In particular, the probabilities for observing the reversible efficiency and the least likely efficiency are identical to those of the same machine working under the time-reversed driving. For time-symmetric drivings, this reversible and the least probable efficiency coincide.

  7. Effect of Binder Content in Cu-In-Se Precursor Ink on the Physical and Electrical Properties of Printed CuInSe2 Solar Cells

    Buffiere, M.; Zaghi, A. E.; Lenaers, N.; Batuk, Maria; Khelifi, S.; DRIJKONINGEN, Jeroen; Hamon, J.; Stesmans, A.; Kepa, J.; Afanas'ev, V. V.; Hadermann, J.; D'HAEN, J.; MANCA, Jean; Vleugels, J.; MEURIS, Marc; POORTMANS, Jef
    Printed chalcopyrite thin films have attracted considerable attention in recent years due to their potential in the high-throughput production of photovoltaic devices. To improve the homogeneity of printed CuInSe2 (CISe) layers, chemical additives such as binder can be added to the precursor ink. In this contribution, we investigate the influence of the dicyandiamide (DCDA) content, used as a binder in the precursor ink, on the physical and electrical properties of printed CISe solar cells. It is shown that the use of the binder leads to a dense absorber, composed of large CISe grains close to the surface, while the bulk...

  8. Spectroscopic ellipsometry characterization of nano-crystalline diamond films prepared at various substrate temperatures and pulsed plasma frequencies using microwave plasma enhanced chemical vapor deposition apparatus with linear antenna delivery

    Mistrik, J.; Janicek, P.; Taylor, A.; Fendrych, F.; Fekete, L.; Jager, A.; NESLADEK, Milos
    A series of nanocrystalline diamond (NCD) films were deposited by a custom made microwave plasma enhanced chemical vapor deposition apparatus with linear antenna delivery at different substrate temperatures (520-600 degrees C) and pulsed plasma frequencies (2.7-14.3 kHz) in a hydrogen rich working gas mixture of H-2/CH4/CO2. Films were deposited onto naturally oxidized Si wafers pre-seeded with nanodiamond particles. Spectro-ellipsometry characterization of the NCD films was carried out considering various model structures (single and bi-layer models) and various NCD optical constant parameterizations (Tauc-Lorentz and effective medium approximation with different non-diamond component representations). It has been shown that substrate temperature can be...

  9. Ensemble and trajectory thermodynamics: A brief introduction

    VAN DEN BROECK, Christian; Esposito, M.
    We revisit stochastic thermodynamics for a system with discrete energy states in contact with a heat and particle reservoir. (C) 2014 Elsevier B.V. All rights reserved.

  10. Microstructural analysis of 9.7% efficient Cu2ZnSnSe4 thin film solar cells

    Buffiere, M.; BRAMMERTZ, Guy; Batuk, Maria; Verbist, C.; Mangin, Denis; Koble, C.; Hadermann, J.; MEURIS, Marc; POORTMANS, Jef
    This work presents a detailed analysis of the microstructure and the composition of our record Cu2ZnSnSe4 (CZTSe)-CdS-ZnO solar cell with a total area efficiency of 9.7%. The average composition of the CZTSe crystallites is Cu1.94Zn1.12Sn0.95Se3.99. Large crystals of ZnSe secondary phase (up to 400 nm diameter) are observed at the voids between the absorber and the back contact, while smaller ZnSe domains are segregated at the grain boundaries and close to the surface of the CZTSe grains. An underlying layer and some particles of CuxSe are observed at the Mo-MoSe2-Cu2ZnSnSe4 interface. The free surface of the voids at the back...

  11. 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...

  12. Multi-element-resolved electrochemical corrosion analysis. Part I. Dissolution behavior and passivity of amorphous Fe50Cr15Mo14C15B6

    Klemm, J.; Klemm, S. O.; Duarte, M. J.; Rossrucker, L.; Mayrhofer, K. J. J.; RENNER, Frank
    Multi-element dissolution analysis of amorphous Fe50Cr15Mo14C15B6 in 0.1 M H2SO4 was investigated electrochemically and by coupled online mass spectrometry. We fully discuss the most important aspects of the application of the newly-developed methodology to study complex multi-elemental alloys. The resulting partial dissolution rates of Fe, Cr and Mo reflect the passive behavior and are compared to the measured total current density as function of time. The deviations between the added elemental dissolution currents and the measured total current density are discussed. Furthermore, the inferred growth of oxide thickness was correlated to results obtained from surface analysis. (C) 2014 The Authors....

  13. Dynamic range extension of hybridization sensors

    Hadiwikarta, W. W.; Carlon, E.; HOOYBERGHS, Jef
    In hybridization based nucleic acid sensors the stringency of hybridization poses a challenge to design and experiment. For a given set of experimental parameters the affinity window of probe target interaction is always limited and vice versa for a given probe set design, changes in experimental conditions can easily bring some measurements out of detection range. In this paper we introduce and apply a strategy to extend this dynamic range for affinity sensors, sensors which measure the amount of hybridized molecules after equilibrium is reached. The method relies on concepts of additivity of nucleic acids hybridization free energies and on...

  14. Echo states for detailed fluctuation theorems

    BECKER, Thijs; WILLAERT, Tim; CLEUREN, Bart; VAN DEN BROECK, Christian
    Detailed fluctuation theorems are statements about the probability distribution for the stochastic entropy production along a trajectory. It involves the consideration of a suitably transformed dynamics, such as the time reversed, the adjoint, or a combination of these. We identify specific, typically unique, initial conditions, called echo states, for which the final probability distribution of the transformed dynamics reproduces the initial distribution. In this case the detailed fluctuation theorems relate the stochastic entropy production of the direct process to that of the transformed one. We illustrate our results by an explicit analytical calculation and numerical simulations for a modulated two-state...

  15. Change of diamond film structure and morphology with N-2 addition in MW PECVD apparatus with linear antenna delivery system

    Krecmarova, Marie Jakl; Petrak, Vaclav; Taylor, Andrew; Kamatchi Jothiramalingam, Sankaran; Lin, I-Nan; Jaeger, Ales; Gaertnerova, Viera; Fekete, Ladislav; Drahokoupil, Jan; Laufek, Frantisek; Vacik, Jiri; Hubik, Pavel; Mortet, Vincent; Nesladek, Milos
    Deposition of nano-crystalline diamond (NCD) over large areas is of high interest for industrial applications. For instance NCD is an excellent substrate for cell growth but it is also interesting for photonic applications associated with nitrogen-vacancy (NV) centres. There have been many studies on the effect of nitrogen addition on the growth of diamond using conventional resonance cavity microwave plasmas (both H and Ar based) but none using MW PECVD apparatus with linear antenna delivery system (MW-LA-PECVD). In this work, we show that an ultra nano-crystalline diamond (UNCD) type of morphology can be prepared upon N-2 addition to H2CO2CH4 plasmas...

  16. Functional mitral stenosis after restrictive annuloplasty for secondary mitral regurgitation: does size really matter?

    Bertrand, P. B.; Smeets, C. J.; Verbrugge, F. H.; GRIETEN, Lars; MULLENS, Wilfried; GUTERMANN, Herbert; Verhaert, D.; Dion, R. A.; Vandervoort, P. M.

  17. 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...

  18. Evaluation of Histamine Imprinted Polypyrrole Deposited on Boron Doped Nanocrystalline Diamond

    Ratautaite, Vilma; NESLADEK, Milos; Ramanaviciene, Almira; Baleviciute, Ieva; Ramanavicius, Arunas
    This study describes the evaluation of histamine imprinted polypyrrole deposited on boron doped nanocrystalline diamond (NCD). Boron doped oxygen terminated NCD (B : NCD) was used as a conducting substrate for the design of here reported electrochemical sensor. Some peculiarities of B : NCD were evaluated and oxidation kinetics of both NCD and B : NCD was investigated. Both the NCD and B : NCD were modified by molecularly imprinted polypyrrole and not-imprinted polypyrrole. Histamine was used as a template for molecular imprinting of polypyrrole. Electrochemical impedance spectroscopy was applied for the evaluation of formed MIP and NIP layers.

  19. Thin silicon foils produced by epoxy-induced spalling of silicon for high efficiency solar cells

    Martini, Roberto; Kepa, J.; Debucquoy, M.; Depauw, V.; Gonzalez, M.; Gordon, I.; Stesmans, A.; POORTMANS, Jef
    We report on the drastic improvement of the quality of thin silicon foils produced by epoxy-induced spalling. In the past, researchers have proposed to fabricate silicon foils by spalling silicon substrates with different stress-inducing materials to manufacture thin silicon solar cells. However, the reported values of effective minority carrier lifetime of the fabricated foils remained always limited to similar to 100 mu s or below. In this work, we investigate epoxy-induced exfoliated foils by electron spin resonance to analyze the limiting factors of the minority carrier lifetime. These measurements highlight the presence of disordered dangling bonds and dislocation-like defects generated...

  20. Process-Induced Degradation of SiO2 and a-Si:H Passivation Layers for Photovoltaic Applications

    O'Sullivan, B. J.; Bearda, Twan; Nadupalli, S.; Labie, Roger; Baert, K.; Gordon, I.; POORTMANS, Jef
    The passivation characteristics of thermally grown silicon dioxide (SiO2) and hydrogenated amorphous silicon (a-Si:H) layers are investigated, using a combination of photoluminescence and capacitance-voltage analysis techniques. Key findings are the significant passivation degradation of SiO2 and a-Si:H layers induced by metallization through electron beam evaporation. The degradation correlates with an increase in silicon dangling bond defect density at the interface with silicon (for both SiO2 and a-Si:H) or in the passivation layer (a-Si:H). Performing the metallization by thermal evaporation is an effective method to avoid such process-induced damage, as is forming gas annealing at 450 degrees C, which effectively recovers...

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