PROSPECTS OF AN IMPROVED SYSTEM PROTECTION SCHEME AGAINST VOLTAGE INSTABILITY IN THE RTE SYSTEM
Capitanescu, Florin ; ; et al
This paper reports on prospective tests of a system protection scheme against long-term voltage instability relying on a set of distributed controllers, each monitoring a transmission voltage, blocking ... [more ▼]
This paper reports on prospective tests of a system protection scheme against long-term voltage instability relying on a set of distributed controllers, each monitoring a transmission voltage, blocking tap changers and shedding loads in a zone. The emergency actions adjust in magnitude and location to the disturbance. Each controller acts in closed loop, which guarantees robustness. The method is illustrated on a real-life model of the Western region of the RTE system. The choice of the controller settings is discussed in some detail and examples of performance are given, combining the above remedial action with capacitor switching and secondary voltage control. [less ▲]Detailed reference viewed: 80 (7 ULg)
Prospects of application to the French system of fast methods for transient stability and voltage security assessment
; ; et al
in Proc. 1992 CIGRE Conference (1992, August)Detailed reference viewed: 19 (1 ULg)
The prospects of detecting exo-planets with the Ground-based European Nulling Interferometer Experiment (GENIE)
; Absil, Olivier ; et al
in Aime, C.; Vakili, F. (Eds.) Direct Imaging of Exoplanets: Science & Techniques (2006)
The European Space Agency's Darwin and NASA's Terrestrial Planet Finder (TPF) are among the most challenging space science missions ever considered. Their principal objective is to detect Earth-like ... [more ▼]
The European Space Agency's Darwin and NASA's Terrestrial Planet Finder (TPF) are among the most challenging space science missions ever considered. Their principal objective is to detect Earth-like planets around nearby stars and to characterize their atmospheres. Darwin and TPF-I are currently conceived as nulling interferometers with free-flying telescopes. Within the frame of the Darwin program, the ESA and the European Southern Observatory (ESO), supported by European industries and scientific institutes, have performed two parallel Phase A studies of a ground-based nulling interferometry experiment (GENIE) at the site of ESO's Very Large Telescope Interferometer (VLTI) in Paranal, Chile. GENIE will demonstrate several key technologies required for the Darwin mission. Its science objectives include the detection and characterization of dust disks and low-mass companions around nearby stars. These studies have established detailed instrumental designs, in which GENIE will operate in the L' band around 3.8 microns as a single Bracewell nulling or constructive interferometer, using either two Auxiliary or two Unit Telescopes. The studies were supported by detailed numerical simulations which indicated the possibility of detection and low-resolution spectroscopy in nulling mode of extra-solar giant planets (EGPs) with atmospheric temperatures down to 700 K, provided that a proper calibration of instrumental effects is applied. Detection of circumstellar exo-zodiacal (EZ) dust clouds is possible down to 0.5 mJy, with interesting prospects for the characterization of planet-forming disks. [less ▲]Detailed reference viewed: 3 (0 ULg)
Prostaglandin D2 affects the differentiation and functions of human dendritic cells: impact on the T cell response.
; ; et al
in European Journal of Immunology (2005), 35(5), 1491-1500
The local environment in which dendritic cells (DC) differentiate is important for the acquisition of their immunostimulatory properties. Since prostaglandin D(2) (PGD(2)), a major prostanoid produced ... [more ▼]
The local environment in which dendritic cells (DC) differentiate is important for the acquisition of their immunostimulatory properties. Since prostaglandin D(2) (PGD(2)), a major prostanoid produced during inflammatory reactions, is involved in the control of immune responses, its effect on the differentiation and functions of human monocyte-derived dendritic cells (MDDC) was studied. We show that DC differentiated in the presence of PGD(2) (PG/DC) have an unusual phenotype, with modifications in the expression of molecules involved in antigen (Ag) capture and presentation, leading to higher endocytic and Ag-processing activities. However, under conditions that necessitated Ag processing and presentation, PG/DC have an impaired ability to stimulate naive T cells, whereas superAg-pulsed DC efficiently promote their proliferation. Upon lipopolysaccharide or TNF-alpha/IL-1beta stimulation, PG/DC phenotypically mature but produce abnormal amounts of immunoregulatory cytokines (decreased IL-12p70/IL-10 ratio). Moreover, mature PG/DC fail to up-regulate the chemokine receptor CCR7 and show an impaired migration towards its ligand CCL19. Finally, PG/DC favor the differentiation of naive T cells toward Th2 cells, an effect dependent on IL-10 and inducible costimulator ligand expression by DC. Most of the herein described effects of PGD(2) on MDDC can be reproduced, usually with a higher efficacy, with a selective D prostanoid receptor (DP)1, but not DP2, agonist. Taken as a whole, these results demonstrate that PGD(2) impacts DC differentiation and functions, and extend the concept that it exerts important roles in immunity [less ▲]Detailed reference viewed: 12 (2 ULg)
Prostaglandin D2 affects the differentiation of human dendritic cells
; Bureau, Fabrice ; et al
Poster (2003)Detailed reference viewed: 4 (0 ULg)
Prostaglandin D2 affects the maturation of human monocyte-derived dendritic cells: consequence on the polarization of naive Th cells.
; Bureau, Fabrice ; et al
in Journal of Immunology (2003), 170(10), 4943-52
Among the factors produced at inflammatory sites and those capable of modulating dendritic cell (DC) functions, PGD(2) may be important in the outcome of immune responses. The biological roles for PGD(2 ... [more ▼]
Among the factors produced at inflammatory sites and those capable of modulating dendritic cell (DC) functions, PGD(2) may be important in the outcome of immune responses. The biological roles for PGD(2) are in part effected through two plasma membrane G protein-coupled receptors: the D prostanoid (DP) receptor and the chemoattractant receptor-homologous molecule expressed on Th2 lymphocytes (CRTH2). In this report, we studied the effects of PGD(2) and of its major physiological metabolite, 15-deoxy-Delta(12,14)-PGJ(2) (15d-PGJ(2)), on the functions of human monocyte-derived DC. First, we show that PGD(2) exerts in vitro chemotactic effects on monocytes via CRTH2 activation while it inhibits the chemokine-driven migration of monocyte-derived DC through DP. We also report that PGD(2) and 15d-PGJ(2) alter the LPS- and allergen-induced DC maturation and enhance the CD80/CD86 ratio on mature DC in a DP- and CRTH2-independent manner. Moreover, PGD(2) and 15d-PGJ(2) strongly reduce the secretion of the Th1 promoting cytokine IL-12 and affect the synthesis of chemokines involved in Th1 cell chemotaxis, particularly CXCL10. Inhibition of cytokine/chemokine secretion implicates at least in part DP, but not CRTH2. The effects exerted by PGD(2) are associated with the phosphorylation of CREB, but do not parallel with the deactivation of the NF-kappa B and mitogen-activated protein kinase pathways. In contrast, 15d-PGJ(2) seems to target other cellular proteins. Finally, in a model of Th CD45RA(+) differentiation induced by allergen- and superantigen-pulsed DC, PGD(2) impacts on the orientation of the immune response by favoring a Th2 response [less ▲]Detailed reference viewed: 32 (4 ULg)
Prostaglandin D2 inhibits the production of interleukin-12 in murine dendritic cells through multiple signaling pathways.
; ; Bureau, Fabrice et al
in European Journal of Immunology (2003), 33(4), 889-898
Prostaglandin (PG) D(2), and its metabolites, are known to be important mediators during acute and chronic inflammation. However, their functions during the early phases of the immune response are poorly ... [more ▼]
Prostaglandin (PG) D(2), and its metabolites, are known to be important mediators during acute and chronic inflammation. However, their functions during the early phases of the immune response are poorly documented. In the present study, we show that PGD(2 )inhibits, in a dose-dependent manner, the CD40- and LPS-induced secretion of the Th1-driving factor IL-12 by murine splenic dendritic cells (DC), the most potent antigen-presenting cells. The inhibition of IL-12 production is mediated only in part by the cell surface G alpha s protein-coupled D prostanoid receptor (termed DP1) but not by the G alpha i protein-coupled DP receptor, DP2. We show that recruitment of DP1 in DC results in the activation of a cyclic AMP/protein kinase A pathway that is partially responsible for the inhibition of IL-12 production. We also suggest that the DP1-independent effects exerted by PGD(2) on IL-12 production may be due to the action of ist PGJ(2), but not PGF(2)alpha, metabolites. Electrophoretic mobility shift assays demonstrated that PGD(2) affects NF-kappa B activation through (the) DP1-independent pathway(s). Together these data suggest that PGD(2), by interacting with DP1 and by binding to other target cellular proteins, may regulate immune responses by affecting IL-12 production in DC [less ▲]Detailed reference viewed: 37 (1 ULg)
Prostaglandin E2 induces the expression of functional inhibitory CD94/NKG2A receptors in human CD8+ T lymphocytes by a cAMP-dependent protein kinase A type I pathway.
Zeddou, Mustapha ; Greimers, Roland ; et al
in Biochemical Pharmacology (2005), 70(5), 714-24
The CD94/NKG2A heterodimer is a natural killer receptor (NKR), which inhibits cell-mediated cytotoxicity upon interaction with MHC class I gene products. It is expressed by NK cells and by a small ... [more ▼]
The CD94/NKG2A heterodimer is a natural killer receptor (NKR), which inhibits cell-mediated cytotoxicity upon interaction with MHC class I gene products. It is expressed by NK cells and by a small fraction of activated T cells, predominantly of CD8+ phenotype. Abnormal upregulation of the CD94/NKG2A inhibitory NKR on cytotoxic T cells (CTLs) could be responsible for a failure of immunosurveillance in cancer or HIV infection. In an attempt to identify the mechanisms leading to inhibitory NKR upregulation on T cells, we analyzed the expression of the CD94/NKG2A heterodimer on human CTLs activated with anti-CD3 mAb in the presence of PGE2 or with 8-CPT-cAMP, an analogue of cyclic AMP. As previously described, anti-CD3 mAb-mediated activation induced the expression of CD94/NKG2A on a small fraction of CD8+ T cells. Interestingly, when low concentrations of PGE2 or 8-CPT-cAMP were present during the culture, the proportion of CD8+ T cells expressing CD94/NKG2A was two- to five-fold higher. This upregulation was partially prevented by PKA inhibitors, such as KT5720 and Rp-8-Br-cAMP (type I selective). We also report that cAMP induces upregulation of NKG2A at the mRNA level. We further demonstrated that cross-linking of CD94 on CD8+ T cells expressing the CD94/NKG2A heterodimer inhibits their cytotoxic activity in a bispecific antibody redirected lysis assay. Our findings clearly demonstrate that the PGE2/cAMP/PKA type I axis is involved in the expression of CD94/NKG2A receptor on human CD8+ T lymphocytes. [less ▲]Detailed reference viewed: 49 (4 ULg)
Prostaglandin E2, prostacyclin, and thromboxane changes during nonpulsatile cardiopulmonary bypass in humans.
Faymonville, Marie ; Deby, Ginette ; Larbuisson, Robert et al
in Journal of Thoracic and Cardiovascular Surgery (The) (1986), 91(6), 858-66
To study the effect of lung bypass on the production of prostaglandin E2, prostacyclin, and thromboxane A2, we measured simultaneously arterial and venous plasma concentrations of prostaglandin E2, 6-keto ... [more ▼]
To study the effect of lung bypass on the production of prostaglandin E2, prostacyclin, and thromboxane A2, we measured simultaneously arterial and venous plasma concentrations of prostaglandin E2, 6-keto-prostaglandin F1 alpha (stable metabolite of prostacyclin), and thromboxane B2 (stable metabolite of thromboxane A2) before, during, and after cardiopulmonary bypass. Seventeen patients (age range 46 to 69 years) undergoing aorta-coronary bypass grafts were investigated. The prostaglandin E2 production rose sharply immediately after the onset of bypass (baseline: 9.7 +/- 2.9 pg/ml to 85 +/- 16.6 pg/ml in venous and 87 +/- 12 pg/ml in arterial plasma, p less than 0.03) and rapidly decreased after pulmonary reperfusion (53 +/- 6.4 and 57 +/- 20 pg/ml, respectively, in venous and arterial plasma at the end of bypass). The increase in prostaglandin E2 was influenced by the heart-lung machine itself (as demonstrated by a closed "bypass" circuit) and by lung bypass. Pulmonary metabolism of prostaglandin E2 was maintained after bypass. The prostacyclin production rose significantly at the beginning of bypass (154 +/- 26 pg/ml venous prebypass level to 361 +/- 94 pg/ml after aortic clamping, p less than 0.03). Prostacyclin decreased progressively during rewarming of the patient, pulmonary reperfusion, and discontinuation of bypass. When prostacyclin decreased, thromboxane B2 production rose significantly and reached peak arterial levels when the lungs were reperfused (112 +/- 33 pg/ml prebypass levels to 402 +/- 101 pg/ml, p less than 0.01). Except for prostaglandin E2, there were no significant differences between arterial and venous plasma levels of these substances. The same prostanoids were also measured in five patients undergoing major orthopedic operations, and no significant changes in prostanoids were observed. Our data demonstrate significant production of prostaglandin E2 in the systemic circulation during cardiopulmonary bypass in humans. They further indicate that lung bypass disturbs the plasma prostaglandin/thromboxane balance. [less ▲]Detailed reference viewed: 32 (2 ULg)
La prostaglandine F2alpha. Voies d’utilisation et applications au traitement des endométrites chroniques chez la vache.
Conference given outside the academic context (2003)Detailed reference viewed: 24 (1 ULg)
Les prostaglandines : biosynthèse et pharmacologie
in Annales de Médecine Vétérinaire (1983), 127Detailed reference viewed: 62 (4 ULg)
Prostaglandines et cycle sexuel chez les animaux domestiques
; Ectors, Francis ; Beckers, Jean-François
in Bulletin et Mémoires de l'Académie Royale de Médecine de Belgique (1976), 131
In some domestic animal species, cow, ewe, sow, mare, luteal regression and therefore oestral regulation, depends on the action of a luteolytic of uterine origin. This luteolysine should be but a ... [more ▼]
In some domestic animal species, cow, ewe, sow, mare, luteal regression and therefore oestral regulation, depends on the action of a luteolytic of uterine origin. This luteolysine should be but a prostaglandin F2 alpha or an analogue. Progesterone is the regulator of the cycle; plasma level is low (basic level) at day of oestrus (0,5ng/ml) then increases gradually to reach a peak value of 6 to 9 ng/ml at days 6 to 16 of the cycle. Beta-oestradiol level fluctuates including a main peak before ovulation (9 pg/ml) and three accessory peaks at days 4-5, 8, 12-14 of the cycle; however the peak of the 8th day is inconstant. FSH and LH levels are constant during dioestrus, peak level values are observed at the beginning of oestrus, they are practically superposed and of a 6 to 9 hours duration. Administration of prostaglandins during luteal phase produces hormonal changes similar to those observed during the normal cycle. Because of its luteolytic action and its effect on uterine fibre, prostaglandin F2 alpha offers a special interest for stock farming and veterinary medicine. So a full expression can be given to AI and a more extended application of egg transfer can be foreseen. It constitutes an effective therapy in the case of corpus luteum persistence and a way to induce parturition. [less ▲]Detailed reference viewed: 573 (3 ULg)
Prostaglandines et physiologie de la reproduction humaine et animale.
in Journal de Gynécologie, Obstétrique et Biologie de la Reproduction (1984), 13(4), 351-61
This review of 417 publications in the literature covers various aspects of the role of prostaglandins in human and animal reproductive physiology. The author points out that there are a variety of ... [more ▼]
This review of 417 publications in the literature covers various aspects of the role of prostaglandins in human and animal reproductive physiology. The author points out that there are a variety of prostaglandins all belonging to a family of substances that derive from arachadonic acid. They are present in many human and animal tissues, are extremely labile and are involved in reproduction in the ovary in follicular development and release of the follicle, in the tube in migration of the gametes, and in the uterus in implantation and delivery. The author says that the role of prostaglandins is not an exclusive one but they are linked with the hypothalamo-pituitary hormones, as well as with progesterone and oestrogens. It may be possible that PGE helps to initiate follicular development by stimulating the appearance of LH and FSH receptors. PGE is also luteotrophic. Indomethacin which is a prostaglandin inhibitor however does not modify the ability of LH to stimulate luteinization and maturation of the oocyte. The author postulates on the origin and the identification of the luteolytic factor and gives schematic illustration of the arterio-venous blood supply between the uterus and the ovary which is so important for the good function of the prostaglandins. It is possible that PGF type prostaglandins which are vasoconstrictor may reduce the flow of blood around the ovary, perhaps even specifically to luteal tissue. He postulates that PGF2 alpha in its relationship to its receptors is necessary but insufficient to explain the full luteolytic effect. Turning to the semen he shows that the nature and concentration of prostaglandins in semen varies from one species to another. He thinks that there is a triple role for prostaglandins with semen, which is: a participation in the events of ejaculation, an effect on the female genital tract, and an effect on the mobility of spermatozoa. He speaks of the role of prostaglandins on the Fallopian tubes and believes that they do have an effect on determining the movement of the tubes but cannot explain exactly what. [less ▲]Detailed reference viewed: 257 (3 ULg)
Prostaglandines et reproduction animale: données générales
Hanzen, Christian ; Drion, Pierre
in Le grand livre des prostaglandines (2003)Detailed reference viewed: 81 (15 ULg)
Prostaglandines, secretion d'insuline et diabete sucre.
; ; Scheen, André et al
in Diabète & Métabolisme (1988), 14(6), 721-7
The islets of Langerhans have the enzymatic equipment permitting the synthesis of the metabolites of arachidonic acid: cyclo-oxygenase and lipo-oxygenase. Numerous studies have shown that cyclo-oxygenase ... [more ▼]
The islets of Langerhans have the enzymatic equipment permitting the synthesis of the metabolites of arachidonic acid: cyclo-oxygenase and lipo-oxygenase. Numerous studies have shown that cyclo-oxygenase derivatives, mainly PGE2, reduce the insulin response to glucose whereas lipo-oxygenase derivatives, mainly 15-HPETE, stimulate insulin secretion. So, for instance, drugs that increase prostaglandins synthesis as colchicine or furosemide inhibit insulin secretion while non steroid anti-inflammator drugs, mainly salicylates, which inhibit cyclo-oxygenase, enhance the insulin response to various stimuli. In type-2 (non insulin-dependent) diabetes, an increased sensitivity to endogenous prostaglandins has been proposed as a possible cause for the insulin secretion defect which characterizes this disease. Play in favor of this hypothesis the fact that the administration of PGE inhibits the insulin response to arginine in type-2 diabetics but not in normal subject and the fact that the administration of salicylates could improve the insulin response to glucose in some of these patients. [less ▲]Detailed reference viewed: 57 (0 ULg)
Prostatic androgen repressed message-1 (PARM-1) may play a role in prostatic cell immortalisation.
Cornet, Anne ; ; et al
in Prostate (The) (2003), 56(3), 220-30
BACKGROUND: Prostatic androgen-repressed message-1 (PARM-1) has been cloned from the prostate. The transcript of the PARM-1 gene is overexpressed during regression of the prostate after androgen ... [more ▼]
BACKGROUND: Prostatic androgen-repressed message-1 (PARM-1) has been cloned from the prostate. The transcript of the PARM-1 gene is overexpressed during regression of the prostate after androgen withdrawal. The regulation of PARM-1 by androgens is limited to this organ. We have studied the effects of PARM-1 overexpression in malignant prostate cells. METHODS: The PARM-1 cDNA was introduced into the rat cancer cell line MAT LyLu along with a doxycycline-dependent regulator. RESULTS: Maximal expression of PARM-1 (fivefold induction) was achieved by incubating the cells with 2 microM doxycycline for 48 hr. A study investigating the effect of PARM-1 overexpression on the transcription of 588 genes has shown that the TLP1 gene (encoding rat telomerase protein component 1) was the most up-regulated (fourfold). In addition, a dose-dependent increase in telomerase activity was observed in cells overexpressing PARM-1. In vivo, the androgen-deprived prostate showed an increased TLP1 level and increased telomerase activity. CONCLUSIONS: Increased telomerase activity is often associated with the immortalisation of cancer cell lines, particularly prostatic ones. This could mean that PARM-1 is involved, via increased telomerase activity, in a survival program enabling certain prostatic cells to resist apoptosis, thus conferring a selective advantage to pre-cancerous or cancerous cells. [less ▲]Detailed reference viewed: 19 (1 ULg)
Prosthesis-patient mismatch after mitral valve replacement: Back to reality
; Magne, Julien ;
in Journal of Thoracic and Cardiovascular Surgery (The) (2008), 135(2), 464-465Detailed reference viewed: 5 (2 ULg)
Prosthesis-Patient Mismatch is an independent Predictor of Short-term Mortality Following Mitral Valve Replacement.
Magne, Julien ; ; et al
Conference (2008)Detailed reference viewed: 3 (0 ULg)
Prosthetic vascular infection complicated or not by aortoenteric fistula: comparison of treatment with and without cryopreserved allograft (homograft).
Lavigne, Jean-Paul ; Postal, Alain ; Kolh, Philippe et al
in European Journal of Vascular and Endovascular Surgery (2003), 25(5), 416-23
OBJECTIVES: in patients with vascular prosthesis infection, to compare surgical outcome and long-term results of cryopreserved allograft implantations to conventional surgery. DESIGN: retrospective study ... [more ▼]
OBJECTIVES: in patients with vascular prosthesis infection, to compare surgical outcome and long-term results of cryopreserved allograft implantations to conventional surgery. DESIGN: retrospective study. MATERIAL AND METHODS: two asynchronous series of 44 [series I: 1980-1994; 8 patients with aortoenteric fistula (AEF)] and 22 (series II: 1994-1997; 4 patients with AEF) patients were treated for prosthesis infection. All patients had prosthesis excision. In series I, there were 4 in situ reparations, 26 extra-anatomic bypass, 13 excision only, and one death at laparotomy. In series II, in situ cryopreserved allografts were implanted in all patients. RESULTS: operative mortality was 16% in series I and 13.6% in series II. For AEF patients, mortality was 37% in series I and 50% in series II. Among hospital survivors, infection-related late mortality was 13.5% in series I and 5% in series II. For AEF patients, late mortality was 20% in series I and 50% in series II. Incidence of reoperations was 54% in series I and 10.5% in series II (p<0.01). Hospital stay was 47.2+/-26.4 days in series I and 16.6+/-11.5 days in series II (p<0.001). CONCLUSIONS: compared to conventional treatment, incidence of reoperations and length of hospital stay are significantly decreased after cryopreserved allograft implantation. However, closure of aortic stump and extra-anatomic bypass gives better results for patients with AEF. [less ▲]Detailed reference viewed: 58 (0 ULg)