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Peer Reviewed
See detailComparison of Ce and LC methods for the determination of B vitamins in pharmaceutical dosage forms
Fotsing, Lucas ULg; Fillet, Marianne ULg; Bechet, I. et al

in Journal de Pharmacie de Belgique (1995), 50

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See detailComparison of centralized, distributed and hierarchical model predictive control schemes for electromechanical oscillations damping in large-scale power systems
Wang, Da ULg; Glavic, Mevludin ULg; Wehenkel, Louis ULg

in International Journal of Electrical Power & Energy Systems (2014), 58

The paper investigates the feasibility of applying Model Predictive Control (MPC) as a viable strategy to damp wide-area electromechanical oscillations in large-scale power systems. First a fully ... [more ▼]

The paper investigates the feasibility of applying Model Predictive Control (MPC) as a viable strategy to damp wide-area electromechanical oscillations in large-scale power systems. First a fully centralized MPC scheme is considered, and its performances are evaluated first in ideal conditions and then by considering state estimation errors and communication delays. This scheme is further extended into a distributed scheme with the aim of making it more viable for very large-scale or multi-area systems. Finally, a robust hierarchical multi-area MPC scheme is proposed, introducing a second layer of MPC based controllers at the level of individual power plants and transmission lines. Simulations are carried out using a 70-bus test system. The results reveal all three MPC schemes as viable solutions to supplement existing controllers in order to improve the system performance in terms of damping. The hierarchical scheme is the one combining the best performances in nominal conditions and the best robustness with respect to partial component failures and various modeling and measurement errors. [less ▲]

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See detailComparison of change in bone resorption and bone mineral density with once-weekly alendronate and daily risedronate: a randomised, placebo-controlled study
Hosking, D.; Adami, S.; Felsenberg, D. et al

in Current Medical Research & Opinion (2003), 19(5), 383-394

Objective: To compare the effects of alendronate (ALN) 70 mg once weekly (OW) and risedronate (RIS) 5 mg daily between-meal dosing on biochemical markers of bone turnover and bone mineral density (BMD) in ... [more ▼]

Objective: To compare the effects of alendronate (ALN) 70 mg once weekly (OW) and risedronate (RIS) 5 mg daily between-meal dosing on biochemical markers of bone turnover and bone mineral density (BMD) in postmenopausal women with osteoporosis. Research design and methods: This was a 3-month, randomised, double-blind, placebo-controlled study with a double-blind extension to 12 months. The study enrolled 549 postmenopausal women (ALN 219, RIS 222 and placebo (PBO) 108) who were : 60 years of age at outpatient centres. Main outcome measures: The primary endpoint was reduction in urine N-telopeptides of type 1 collagen (NTx) corrected for creatinine level at 3 months. Secondary parameters included change in BMD at the spine and hip at 6 and 12 months, NTx at 1, 6 and 12 months, and serum bone-specific alkaline phosphatase (BSAP) at 1, 3, 6 and 12 months. Adverse experiences (AEs) were recorded throughout the study for an assessment of treatment safety profiles and tolerability. Results: Over 3 months, ALN produced a significantly greater mean reduction in urine NTx than did RIS (-52% vs -32%, p < 0.001), which was maintained at 12 months. ALN produced a significantly greater mean BMD increase than did RIS at 6 months, and it was maintained at 12 months at the lumbar spine (4.8% vs 2.8%, p < 0.001) and total hip (2.7% vs 0.9%, p < 0.001), as well as at the trochanter and femoral neck. Significant reductions in BSAP with ALN compared to RIS were maintained over the 12 months of treatment. Study size did not allow for meaningful assessment of differences in fracture rates. Tolerability was generally similar between ALN, RIS and PBO, and the incidence of upper GI AEs causing discontinuation and oesophageal AEs was similar in the ALN and RIS groups. Conclusion: In this study, ALN 70 mg OW produced a 50% greater reduction in bone resorption as measured by urine NTx and significantly greater increases in lumbar spine and hip BMD than did RIS 5 mg daily. The treatments had similar safety profiles and were generally well-tolerated. Additional studies are needed comparing OW ALN with OW RIS, which became available after the commencement of the present study. [less ▲]

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See detailComparison of chitosan/siRNA and trimethylchitosan/siRNA complexes behaviour in vitro
Dehousse, Vincent ULg; Garbacki, Nancy ULg; Jaspart, Séverine ULg et al

in International Journal of Biological Macromolecules (2010), 46

Chitosan and trimethylchitosan (TMC)-siRNA nanoparticles were produced by simple complexation technique or by ionic gelation using tripolyphosphate (TPP). The obtained complexes were characterized in ... [more ▼]

Chitosan and trimethylchitosan (TMC)-siRNA nanoparticles were produced by simple complexation technique or by ionic gelation using tripolyphosphate (TPP). The obtained complexes were characterized in terms of physicochemical properties such as size, zeta potential, complexation efficiency and stability. Furthermore, cytotoxicity, cell uptake and transfection efficiency of polyplexes were evaluated in vitro. Under pH condition of cell culture medium, a strong decrease in siRNA condensation efficiency was observed with chitosan nanoparticles. This characteristic resulted in low transfection efficiencies in HEK293 cell line. Formulation of chitosan polyplexes with TPP led to improvement of polyplexes stability but no significant increase in transfection efficiency was observed compared to simple chitosan complexes. By contrast, TMC complexes did not have pH dependency on siRNA complexation. TMCsiRNA nanoparticles were stable in physiological condition. Accordingly, cellular uptake was increased compared to chitosan polyplexes. However, improvement of transfection efficiency was low regarding to cellular uptake of these complexes. Chitosan and TMC complexes present some characteristics favourable for siRNA delivery, such as ability to integrate siRNA into small discrete particles or low toxicity of the complexes. This study also highlights the importance of complexes stability in physiological environment for siRNA transfection purposes. [less ▲]

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See detailComparison of composition and quality traits of meat from young finishing bulls from Belgian Blue, Limousin and Aberdeen Angus breeds
Cuvelier, Christine ULg; Clinquart, Antoine ULg; Hocquette, Jean-François et al

in Meat Science (2006), 74(3), 522-531

Thirty-six young finishing bulls from three breeds (Belgian Blue, Limousin and Aberdeen Angus) were fattened over five months with finishing diets based either on sugar-beet pulp or on cereals ... [more ▼]

Thirty-six young finishing bulls from three breeds (Belgian Blue, Limousin and Aberdeen Angus) were fattened over five months with finishing diets based either on sugar-beet pulp or on cereals. Nutritional quality traits of meat - fat content and fatty acid composition with emphasis on the n - 6 and n - 3 polyunsaturated fatty acids - along with some organoleptic quality traits were measured. The Belgian Blue bulls had the lowest intramuscular fat content associated with lower saturated and monounsaturated fatty acid contents. The polyunsaturated fatty acid content did not differ to a large extent between the breeds, the Aberdeen Angus bulls showing slightly higher values. Relative to energy intake, the overall contribution of meat to the n - 3 fatty acid recommended intake was small, whatever the breed. By contrast, the contribution of meat to daily fat intake was of greater importance, especially for the Aberdeen Angus bulls. The quality traits of meat varied also according to the breed: compared to the Aberdeen Angus, the Belgian Blue bull meat had the stablest colour, the highest drip and the lowest cooking losses. The meat of Limousin bulls had intermediate characteristics for all the parameters. (c) 2006 Elsevier Ltd. All rights reserved. [less ▲]

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See detailComparison of conjugation procedures for the preparation of monoclonal antibody-enzyme conjugates
Jeanson, Antoinette; Cloes, Jean-Michel; Bouchet, Mireille et al

in Journal of Immunological Methods (1988), 111(2), 261-270

Four monoclonal antibodies belonging to different subclasses and with differing isoelectric points were coupled to horseradish peroxidase (HRP) and alkaline phosphatase (AP) using various conjugation ... [more ▼]

Four monoclonal antibodies belonging to different subclasses and with differing isoelectric points were coupled to horseradish peroxidase (HRP) and alkaline phosphatase (AP) using various conjugation procedures. The conjugates were tested by enzyme immunoassay and their efficiency was characterized by the antibody and enzyme concentrations needed to obtain an arbitrary OD value. The suitability of antibody for conjugation through NH2 groups was tested by fluorodinitrobenzene (FDNB). HRP conjugates were produced by two variants of the sodium periodate procedure and two variants of the glutaraldehyde method, as well as by the heterobifunctional linker N-succinimidyl 3-(2-pyridyldithio)pro-pionate (SPDP). Two of the four antibodies were coupled by a third variant of the periodate method, through their carbohydrate moieties. The periodate-mediated conjugations, using sugar moieties on the enzyme, provided the most efficient HRP conjugates, regardless of the antibody subclass or isoelectric point. The glutaraldehyde procedures consistently gave the worst results. AP conjugates were prepared using the same methods. The most efficient and reproducible AP conjugates with all four monoclonal antibodies were obtained using the SPDP procedure. The efficiency of the other methods differed from one antibody to another. [less ▲]

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See detailComparison of continuous background in-situ and column integrated CO2 observations at Jungfraujoch with an urban site in the city of Bern
Schibig, Michael; Leuenberger, Markus; Nyfeler, Peter et al

in Geophysical Research Abstracts (2014), 16

A six and a half year (January 2005 to May 2011) comparison of CO2 concentration observations has been performed at Jungfraujoch, Switzerland and the city of Bern using two different measurement ... [more ▼]

A six and a half year (January 2005 to May 2011) comparison of CO2 concentration observations has been performed at Jungfraujoch, Switzerland and the city of Bern using two different measurement techniques run by the University of Bern (UBE) and the University of Liege (UL). The UBE systems at Jungfraujoch and Bern are both combined systems for atmospheric oxygen and CO2 measurements. The cryogenically dried air is analysed for CO2 with a Maihak analyser based on the broad-band infrared absorption technique. The measurement frequency is every second but the final reported data are averages of six minute periods. UL is measuring the solar infrared spectrum since 1950 at Jungfraujoch. On its way through the atmosphere, the solar spectrum is modulated depending on the abundant gas species and their amount in the column. Since some gases like CO2 absorb the solar infrared radiation at particular wavelengths and the extinction is proportional to the gas concentration, it is possible to determine the gas concentration in the column above the sensor. At the conference, we will present the three observational records for the six and a half year period. The results show for all three records a distinct, but different seasonality. The seasonalities of the UL and UBE record at Jungfraujoch are lower than the seasonality in the city of Bern, i.e. 4.5 ppm per year and 9 ppm per year for the column and the in- situ record respectively, whereas the seasonality in the city of Bern is 31 ppm per year. Also the maxima and minima of the Jungfraujoch measurements are delayed by several weeks compared to the measurements in the city of Bern. The annual increase of the CO2 concentration of the UBE and UL records of Jungfraujoch are in good agreement with 1.94 ppm per year and 1.90 ppm per year, respectively. The annual increase of the CO2 concentration at the urban site is a bit higher at 2.01 ppm per year. [less ▲]

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See detailA Comparison of Contrast and Sensitivity in Tc-99m Thyroid Scintigraphy between Nine Nuclear Medicine Centres of a geographic area
Seret, Alain ULg

in Alasbimn Journal (2006), 32

Purpose: To compare with Picker’s thyroid phantom the contrast and the sensitivity obtained with ten cameras used for Tc-99m thyroid scintigraphy in a geographic area. Methods: The phantom image was ... [more ▼]

Purpose: To compare with Picker’s thyroid phantom the contrast and the sensitivity obtained with ten cameras used for Tc-99m thyroid scintigraphy in a geographic area. Methods: The phantom image was acquired with the collimator and the acquisition parameters used in clinical practice. Contrast for the 12 mm hot (H12) and for the 9 and 12 mm cold (C9, C12) nodules was measured, as well as sensitivity (S in cp/MBq/s). Results: Measured minimum-maximum values were as follows. Pinhole cameras (6): S = 62-131; H12 = 0.66-0.77; C12 = 0.77-0.90; C9 = 0.59-0.76. Non-pinhole cameras (4): S = 55-85; H12 = 0.52-0.59; C12 = 0.62-0.75; C9 = 0.30-50. Conclusions: The pinhole collimators outclass the parallel hole ones in contrast. The sensitivity was the highest (S > 96) for five of the six pinhole collimators. As a direct consequence of this study, two centres decided to switch to pinhole collimator for thyroid scintigraphy. [less ▲]

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See detailComparison of contrast enhanced three dimensional echocardiography with MIBI gated SPECT for the evaluation of left ventricular function
Cosyns, Bernard; Haberman, David; Droogmans, Steven et al

in Cardiovascular Ultrasound (2009), 7

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See detaila comparison of control strategies applied to an existing ice-storage system
Lemort, Vincent ULg

(2005, April)

While ice storage systems are designed according to a defined strategy for warm day loads, it is interesting to consider other conventional control strategies for mid-season day loads. These different ... [more ▼]

While ice storage systems are designed according to a defined strategy for warm day loads, it is interesting to consider other conventional control strategies for mid-season day loads. These different control strategies, applied to an existing cooling plant, are compared in terms of operating costs and energy consumption. A simplified cooling plant model is built. The chillers, cooling towers, and the ice storage system are modeled as different systems connected together. A time stage equal to 15 minutes is considered to simulate the different control strategies. Existing technical constraints and set points are met. The operating costs of the cooling plant are evaluated by taking into account both the energy and the demand cost rate. In off-design conditions, savings of operating costs are made only if the storage tanks are fully discharged after being fully charged. In this case, ice storage systems reduce the operating costs of the cooling plant by shifting a significant fraction of on-peak energy consumption to off-peak periods and by reducing the on-peak demand. But at the same time, the introduction of an ice storage system in a cooling plant causes the electrical energy consumption to rise because the thermal efficiency of the chillers is reduced when working in ice formation mode. [less ▲]

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See detailComparison of control strategies for waste heat recovery Organic Rankine Cycle systems
Lemort, Vincent ULg; Zoughaib, Assaad; Quoilin, Sylvain ULg

(2011, October)

This paper investigates the control of waste heat recovery Organic Rankine Cycle systems. A dynamic simulation model of the system was developed under Modelica language. This model associates the sub ... [more ▼]

This paper investigates the control of waste heat recovery Organic Rankine Cycle systems. A dynamic simulation model of the system was developed under Modelica language. This model associates the sub-models of the different components of the system: the evaporator, a scroll expander, the condenser, the liquid receiver and the pump. Both the speeds of the expander and of the pump are controlled in order to adjust the evaporating pressure and maintain the superheat at the outlet of the evaporator. Two types of controllers were implemented: Proportional Integral (PI) and Model Predictive Control (MPC) controllers. The PI controller on the expander speed is able to adjust the evaporating pressure with a high accuracy. It is also shown that the MPC controller on the pump speed maintains the superheat close to the set point value with a much better performance than the PI controller. Hence, the use of a MPC controller allows decreasing the set point value on the superheat without any risk of feeding the expansion machine with liquid droplets. [less ▲]

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See detailComparison of copy-methods of computer-generated holograms in dichromated gelatin
Habraken, Serge ULg; Roose, Stéphane ULg

in Proceedings of HOLO 3 (1991, November 20)

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See detailComparison of corticosterone, cortisol, triglycerides, aspartateaminotransferase and uric acid plasma concentrations during a foie gras production period in male mule ducks (Anas platyrhynchos X Cairina moschata)
Flament, Aline; Delleur, Valéry ULg; Poulipoulis, Anastassios ULg et al

in British Poultry Science (2012), 53(4), 408-414

1 Corticosterone, cortisol, triglycerides, aspartate aminotransferase (AST) and uric acid (UA) plasma concentration were measured at 8 and 12 weeks of age, at slaughtering and 45 min after an ... [more ▼]

1 Corticosterone, cortisol, triglycerides, aspartate aminotransferase (AST) and uric acid (UA) plasma concentration were measured at 8 and 12 weeks of age, at slaughtering and 45 min after an adrenocorticotrophic hormone (ACTH) stimulation test (8 weeks of age) in twelve male mule ducks. 2 No significant increase of corticosterone was found during the force feeding period. 3 Comparison of corticosterone and cortisol levels indicates that cortisol can be considered as a reliable acute stress indicator in future routine examinations. 4 Triglycerides and AST plasma concentrations progressively increased from pre-force feeding period to slaughtering. 5 UA plasma concentrations also increased from the start at 8 weeks of age to mid-force feeding time but no difference was noticed between mid-force feeding period and slaughtering. [less ▲]

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See detailComparison of cross-field pitting in fresh, dried and charcoalified softwoods
Gerards, Thomas ULg; Damblon, Freddy ULg; Wauthoz, B. et al

in Iawa Journal (2007), 28(1), 49-60

Cross-field pitting is one of the most reliable characters for softwood identifi cation. During charcoalification, a range of severe qualitative and quantitative modifications may occur in cross-field ... [more ▼]

Cross-field pitting is one of the most reliable characters for softwood identifi cation. During charcoalification, a range of severe qualitative and quantitative modifications may occur in cross-field pitting. As most fossil or archaeological wood remains are preserved as charcoal (fusain), the question arises whether these modifications hamper the accurate identification of some taxa. This work is a systematic biometric study of a wide range of gymnosperm cross-field pitting after experimental charcoalification. We focused on the window-like, piceoid, taxodioid, cupressoid, araucarioid and podocarpoid cross-field pitting types. Our main results are the following: 1) Cross-field pits of wood specimens dried out before charcoalification are hidden by a thin closing wall; in this case, it is often impossible to discriminate between the various types of cross-field pitting. 2) Piceoid cross-field pitting becomes taxodioid-like after charcoalification. 3) Biometric study of charred softwood cross-field pitting dimensions shows that the ratios between height and width of pit aperture and border allow us to distinguish and characterise four types of pitting (window-like, piceoid, taxodioid, cupressoid + araucarioid + podocarpoid [= CAP]). The discrimination within the CAP type requires further investigation. [less ▲]

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See detailComparison of Data Transfer Methods between Meshes in the Frame of the Arbitrary Lagrangian Eulerien Formalism
Bussetta, Philippe ULg; Boman, Romain ULg; Ponthot, Jean-Philippe ULg

in Proceedings of "Fifth International Conference on Advanced COmputationalMethods in ENgineering" (2011, November)

In nonlinear solid Mechanics, the Arbitrary Lagrangian Eulerian (ALE) formalism is a common way to avoid mesh distortion when very large deformations occur in the modelled process. Usually, the ALE ... [more ▼]

In nonlinear solid Mechanics, the Arbitrary Lagrangian Eulerian (ALE) formalism is a common way to avoid mesh distortion when very large deformations occur in the modelled process. Usually, the ALE resolution procedure is based on an “operator split”, the second part of which is a Data Transfer between two meshes sharing the same topology (same number of nodes and same number of element neighbours for each of them). Thanks to this interesting property, classical ALE transfer algorithms can bemuchmore optimised in terms of CPU time than the ones that are used in the frame of a complete remeshing. However, the resulting CPU-efficient transfer schemes suffer from two main drawbacks. The first one is a spurious crosswind diffusion coming from the corner fluxes that have been neglected. The second issue is the number of explicit transfer steps which may become very large when the element size decreases. In this paper, these classical ALE Data Transfer methods are compared to more general algorithms which do not make any assumption on the topology of both meshes. [less ▲]

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