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See detailControl of puberty by excitatory amino acid neurotransmitters and its clinical implications
Parent, Anne-Simone ULg; Matagne, V.; Bourguignon, Jean-Pierre ULg

in Endocrine (2005), 28(3), 281-285

Excitatory amino acids, glutamate in particular, have a marked stimulatory effect on the reproductive axis, particulary at puberty. Glutamate, N-methyl-D-aspartate (NMDA), and kainate stimulate ... [more ▼]

Excitatory amino acids, glutamate in particular, have a marked stimulatory effect on the reproductive axis, particulary at puberty. Glutamate, N-methyl-D-aspartate (NMDA), and kainate stimulate gonadotropin-releasing hormone (GnRH) secretion in immature mammals and NMDA receptor stimulation results in precocious puberty in rats and monkeys. Puberty is characterized by an increased sensitivity of GnRH to glutamate as well as an increase in glutaminase activity in the hypothalamus. Glutamatergic and GABAergic regulation of GnRH secretion seem strongly interdependent around puberty. in addition to the transsynaptic glutamatergic regulation of GnRH secretion, a coordinated activity of glutamatergic neurons and astroglial cells has been shown to play an active role in puberty. The participation of kainate receptors in the estradiol-induced advancement of puberty suggest that these receptors may be involved in the estradiol-mediated activation of GnRH secretion at puberty. A case of precocious puberty associated with hyperglycinemia illustrates the NMDA involvement in puberty in humans. in this patient, the occurrence of precocious puberty was thought to result from excessive stimulation by glycine of the NMDA receptors linked to the GnRH neurons. Glutamate plays several roles in the hypothalamic mechanism of puberty as it has been shown in animal models, but there are still few clinical data supporting the role of glutamate in human puberty. [less ▲]

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See detailControl of Pulsatile Secretion of Gonadotrophin Releasing Hormone from Hypothalamic Explants
Bourguignon, Jean-Pierre ULg; Gerard, Arlette ULg; Alvarez Gonzalez, Maria-Luz ULg et al

in Human Reproduction (1993), 8 Suppl 2(NULL), 18-22

We have studied the secretion of gonadotrophin releasing hormone (GnRH) from hypothalamic explants of male rats at different ages in an attempt to delineate the neuroendocrine mechanism of the onset of ... [more ▼]

We have studied the secretion of gonadotrophin releasing hormone (GnRH) from hypothalamic explants of male rats at different ages in an attempt to delineate the neuroendocrine mechanism of the onset of puberty. In this paper, we review some of our recent studies and we provide evidence of a dual control played by receptors to neuroexcitatory amino acids. We showed previously that isolated explants of rat hypothalamus could secrete GnRH in a pulsatile manner. The onset of puberty was characterized by a 2-fold increase in frequency of GnRH secretory pulses. This reduction of the interval between GnRH pulses involved an inhibitory autofeedback effect of GnRH on the pulse generator which was shut off following a secretory episode. This period of refractoriness was longer before puberty than after the onset of puberty. Activation of receptors to neuroexcitatory amino acids (N-methyl-D-aspartate; NMDA-type) was involved in the mechanism of pulsatile GnRH secretion. Striking developmental changes in NMDA-receptor-mediated GnRH secretion were demonstrated with a maximal activity around the time of the onset of puberty. Similar changes occurred in orchidectomized animals, indicating that this maturational process was gonad-independent. While evidence accumulated that NMDA receptors were involved in a stimulatory control of GnRH secretion, we found that NMDA receptors mediated an inhibitory effect on GnRH secretion. This inhibitory effect was very potent in the immature hypothalamus and it showed a marked reduction in potency before onset of puberty.(ABSTRACT TRUNCATED AT 250 WORDS) [less ▲]

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See detailControl of radical reactions by bimetallic systems
Richel, Aurore ULg

Conference (2002)

The original application of ruthenium-titanium bimetallic systems either in ATRP or in Kharasch addition (ATRA) is presented

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See detailControl of radical reactions by transition-metal complexes
Richel, Aurore ULg

Doctoral thesis (2007)

The overall goal of this Ph.D. is to contribute to the conception, the synthesis and the characterisation of original homogeneous ruthenium-based catalytic systems (or heterobimetallic ruthenium-titanium ... [more ▼]

The overall goal of this Ph.D. is to contribute to the conception, the synthesis and the characterisation of original homogeneous ruthenium-based catalytic systems (or heterobimetallic ruthenium-titanium systems), highly active and effective towards atom transfer radical addition (ATRA) and polymerisation (ATRP) of several representative vinyl monomers. As catalytic performances may be tuned by the nature and the structure of the ligands around the metallic core, we are intending to systematically elucidate (by NMR and electrochemistry) the relations between stereoelectronic ligands parameters and the catalytic activity. Microwave irradition is also considered as an unexpected heating source for performing radical reactions. [less ▲]

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See detailControl of radical reactions mediated by bimetallic systems
Richel, Aurore ULg; Delfosse, Sébastien; Demonceau, Albert ULg et al

Poster (2001)

We present herein preliminary results on the use of Ti-Ru bimetallic catalyst systems in Kharasch chemistry and atom transfer radical polymerisation

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See detailControl of Salmonella contamination of shell eggs – preharvest and postharvest methods: a review
Galis, Anca; Marcq, Christopher ULg; Marlier, Didier ULg et al

in Comprehensive Reviews in Food Science and Food Safety (2013), 12

Salmonella Enteritidis is one of the most prevalence foodborne pathogen, its most important reservoir being considered the shell egg. As the concerns related to the increasing human salmonellosis cases ... [more ▼]

Salmonella Enteritidis is one of the most prevalence foodborne pathogen, its most important reservoir being considered the shell egg. As the concerns related to the increasing human salmonellosis cases grow, the need for an application of preventive methods either at the farm level or during the processing steps is crucial for a better control of the foodborne outbreaks due to the consumption of this specific food product. This review focuses on the application of preventive methods at the farm level, on preharvest step, in order to reduce the risk of shell eggs contamination with Salmonella, especially S. Enteritidis, through a better control of the laying hens’ infection with this pathogen. As postharvest methods, a first approach is the egg storage conditions and the prevention of Salmonella spp. growth and multiplication. In addition, shell eggs may be subjected to eggshell decontamination, to reduce the risk of foodborne outbreaks. Several of these latter mentioned methods are already authorized to be put in place in different countries, as it is the case in the United States of America and Canada. Their efficacy has been proven and their use is regarded by some as mandatory for ensuring shell eggs safety for the consumers. [less ▲]

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See detailControl of Schistosoma mansoni egg-induced inflammation by IL-4-responsive CD4+CD25−CD103+Foxp3− cells is IL-10-dependent
Dewals, Benjamin G ULg; Hoving, Jennifer C.; Horsnell, William G.C. et al

in European Journal of Immunology (2010), 40

Host protection to helminth infection requires IL-4Rα signalling and the establishment of finely regulated Th2 responses. In the present study, the role of IL-4Rα-responsive T cells in Schistosoma mansoni ... [more ▼]

Host protection to helminth infection requires IL-4Rα signalling and the establishment of finely regulated Th2 responses. In the present study, the role of IL-4Rα-responsive T cells in Schistosoma mansoni egg-induced inflammation was investigated. Egg-induced inflammation in IL-4Rα-responsive BALB/c mice was accompanied with Th2-biased responses, whereas T cell-specific IL-4R-deficient BALB/c mice (iLckcreIl4ra−/lox) developed Th1-biased responses with heightened inflammation. The proportion of Foxp3+ Tregs in the draining lymph node of control mice did not correlate with the control of inflammation and was reduced in comparison to T cell-specific IL-4R-deficient mice. This was due to IL-4-mediated inhibition of CD4+Foxp3+ Tregs conversion, demonstrated in adoptively transferred Rag2−/− mice. Interestingly, reduced footpad swelling in Il4ra−/lox mice was associated with the induction of IL-4 and IL-10-secreting CD4+CD25−CD103+Foxp3− cells, confirmed in S. mansoni infection studies. Transfer of IL-4Rα-responsive CD4+CD25−CD103+ cells, but not CD4+CD25high or CD4+CD25−CD103− cells, controlled inflammation in iLckcreIl4ra−/lox mice. It finally turned out that the control of inflammation depended on IL-10, as transferred CD4+CD25−CD103+ cells from IL-10-deficient mice were not able to effectively downregulate inflammation. Together, these results demonstrate that IL-4 signalling in T cells inhibits Foxp3+ Tregs in vivo and promotes CD4+CD25−CD103+Foxp3− cells that control S. mansoni egg-induced inflammation via IL-10. [less ▲]

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See detailControl of the biodegradation rate of poly(DL-lactide) microparticles intended as chemoembolisation materials
Grandfils, Christian ULg; Flandroy, P.; Jérôme, Robert ULg

in Journal of Controlled Release (1996), 38(2-3), 109-122

There is an interest in polylactide microspheres that biodegrade within a few days, particularly for chemoembolization applications. For this purpose, two poly(DL-lactide) samples of a very different ... [more ▼]

There is an interest in polylactide microspheres that biodegrade within a few days, particularly for chemoembolization applications. For this purpose, two poly(DL-lactide) samples of a very different molecular weight have been combined. The basic concept relies upon the capability of the high molecular weight component (Mn: 65 000) to provide the microspheres with a high mechanical strength, whereas the low molecular weight component (Mn: 3500) should decrease the particle lifetime dramatically. It has been shown that changing the weight ratio of these two components is an efficient way to control the kinetics of the in vitro degradation of poly(DL-lactide) microspheres on the expected time scale. The microspheres have been prepared by the oil-in-water emulsion/evaporation process, and their final polymer content has been compared to the initial composition of the oil phase. They have also been analyzed by differential scanning calorimetry to know whether the two polymers form a monophase blend or not. Kinetics of the in vitro biodegradation has been estimated from the decrease in molecular weight of the constitutive poly(DL-lactide)s, the time-dependency of the microsphere weight and the observation of changes in the morphology by scanning electron microscopy. Progress in the hydrolysis of the ester groups has also been reckoned from the increasing acidity of the incubation medium and associated with the polymer. [less ▲]

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See detailControl of the Illegal Administration of Natural Steroid Hormones in the Plasma of Bulls and Heifers
Scippo, Marie-Louise ULg; Degand, Guy ULg; Duyckaerts, Anne et al

in Analyst (1994), 119(12), 2639-44

In the context of the control of the illegal administration of natural steroid hormones in cattle husbandry, an attempt was made to establish the decision levels for sex steroid hormones in the plasma of ... [more ▼]

In the context of the control of the illegal administration of natural steroid hormones in cattle husbandry, an attempt was made to establish the decision levels for sex steroid hormones in the plasma of adult cattle, taking into account the effect of the treatment. Bulls and heifers were treated with two injections, at a two week interval, of an estradiol-testosterone cocktail. Steroid hormone and biochemical precursor concentrations were measured in plasma samples by using specific radioimmunoassays, before and after the treatment. When the treatment significantly (p < 0.05) modified a hormone concentration, a decision level was established for that hormone concentration. At each decision level, a score was assigned that represented the percentage of treated animals detected when the decision limit was applied. For heifers, 17 beta-estradiol and testosterone concentrations in plasma, which increased after the treatment, are the best criteria to use to detect treated animals, with decision limits of 20 pg ml-1 and 125 pg ml-1, respectively. In the instance of bulls, both testosterone and steroid biochemical precursor concentrations decreased in the plasma after the treatment. We proposed decision limits of 1500 pg ml-1 and 28 pg ml-1 for testosterone and androstenedione concentrations, respectively, the bulls displaying concentrations below these limits being positive. We observed that the repetition of the injection increased the score of the decision limit. The scores for testosterone are 70%, 14d after the first injection and 100% 14 d after the second injection, and for androstenedione, these scores are 60 and 100%, respectively. [less ▲]

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See detailControl of the illegal administration of natural steroid hormones in urine and tissues of veal calves and in plasma of bulls
Scippo, Marie-Louise ULg; Gaspar, Pol; Degand, Guy ULg et al

in Analytica Chimica Acta (1993), 275(1-2), 57-74

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See detailControl of the porosity of anatase thin films prepared by EISA: Influence of thickness and heat treatment
Henrist, Catherine ULg; Dewalque, Jennifer ULg; Mathis, François ULg et al

in Microporous & Mesoporous Materials (2009), 117

Mesoporous anatase thin films were prepared by the evaporation-induced self-assembly process. This paper reports a study of the influence of several physical parameters on the long-range ordering of the ... [more ▼]

Mesoporous anatase thin films were prepared by the evaporation-induced self-assembly process. This paper reports a study of the influence of several physical parameters on the long-range ordering of the mesopores. A preliminary study was done to set the best humidity conditions during dip-coating and ageing of the films. The withdrawal speed, already known to modify the thickness of the deposited film, was shown to exert a strong influence on the percentage of porosity. This was studied by step profilometry combined with Rutherford backscattered spectrometry (RBS). In parallel, small angle X-ray scattering (SAXS), X-ray diffraction (XRD), transmission electron microscopy (TEM) and RBS were used to tune the precise thermal treatment applied to the so-obtained films, in order to preserve the porous mesostructure and promote the nanocrystallization of anatase TiO2. [less ▲]

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See detailControl of the Radical Polymerization by 2,2,15,15-tetramethyl-1-aza-4,7,10,13-tetraoxacyclopentadecan-1-oxyl and its Sodium Salt
Olive, Gilles ULg; Rozanska, Xavier; Smulders, Wilfred et al

in Macromolecular Chemistry and Physics (2002), 203(12), 1790-1796

The control of the radical polymerization of styrene by 2,2,15,15-tetramethyl-1-aza-4,7,10,13-tetraoxacyclopentadecan-1-oxyl is reported here in bulk at 90 °C, 120 °C and in miniemulsion. Similarly, the ... [more ▼]

The control of the radical polymerization of styrene by 2,2,15,15-tetramethyl-1-aza-4,7,10,13-tetraoxacyclopentadecan-1-oxyl is reported here in bulk at 90 °C, 120 °C and in miniemulsion. Similarly, the control by its sodium complex is reported in bulk at 90 °C. [less ▲]

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See detailControl of the radical polymerization of tert-butyl methacrylate in water by a novel combination of sodium nitrite and iron(II) sulfate
Detrembleur, Christophe ULg; Teyssié, Philippe; Jérôme, Robert ULg

in Macromolecules (2002), 35(5), 1611-1621

Addition of iron(II) sulfate to sodium nitrite is a new way to control the radical polymerization of tert-butyl methacrylate (tBMA) in water at 80 degreesC. Nitric oxide is released in the reaction medium ... [more ▼]

Addition of iron(II) sulfate to sodium nitrite is a new way to control the radical polymerization of tert-butyl methacrylate (tBMA) in water at 80 degreesC. Nitric oxide is released in the reaction medium as result of the reduction of sodium nitrite by FeSO4. This reaction is of utmost importance because three repeated additions of an alkyl radical to nitric oxide leads to the formation of nitroxide radicals. The basic mechanism for the control of the radical polymerization is thus a nitroxide-mediated process. [less ▲]

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See detailControl of the semi-rigid behaviour of civil engineering structural connections
Jaspart, Jean-Pierre ULg

in Control of the semi-rigid behaviour of civil engineering structural connections (1999)

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See detailControl of tumor size and hormonal hypersecretion in acromegaly : a large single-center experience
Daly, Adrian ULg; Tikhomirova, M.; Petrossians, Patrick ULg et al

in European Congress of Endocrinology - Abstract book (2005)

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See detailControl strategies study of a complete solar assisted air conditioning system in an office building using TRNSYS
Thomas, Sébastien ULg; Andre, Philippe ULg

(2009, September)

It is now clearly assumed that solar assisted air conditioning is able to minimize environmental impact and CO2 production of buildings operation. How to reach highest energy savings is still a work in ... [more ▼]

It is now clearly assumed that solar assisted air conditioning is able to minimize environmental impact and CO2 production of buildings operation. How to reach highest energy savings is still a work in progress. In former literature, equipment control has been point out as a critical feature of energy consumption. Control becomes more and more important as system is complex. The complete simulation environment was developed in previous work, it includes the absorption chiller itself, the rejection circuit (cooling tower), solar panels field, heater, storage device, pumps, heating-cooling networks, emission system and building. TRNSYS software modular approach provides the possibility to model and simulate this complete system. In this article, different strategies are proposed to minimize consumption for air-conditioning. [less ▲]

Detailed reference viewed: 80 (19 ULg)