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See detailThe massive binary HD 152218 revisited: A new colliding wind system in NGC 6231
Sana, H.; Nazé, Yaël ULg; O'Donnell, B. et al

in New Astronomy (2008), 13(4), 202-215

We present the results of an optical and X-ray monitoring campaign on the short-period massive SB2 binary HD 152218. Combining our HiRes spectroscopic data with previous observations, we unveil the ... [more ▼]

We present the results of an optical and X-ray monitoring campaign on the short-period massive SB2 binary HD 152218. Combining our HiRes spectroscopic data with previous observations, we unveil the contradictions between the published orbital solutions. In particular, we solve the aliasing on the period and derive a value close to 5.604 d. Our eccentricity e = 0.259 +/- 0.006 is slightly lower than previously admitted. We show that HD 152218 is probably undergoing a relatively rapid apsidal motion of about 3 degrees yr(-1) and we confirm the O9IV + O9.7V classification. We derive minimal masses of 15.82 +/- 0.26 M-circle dot and 12.00 +/- 0.19 M-circle dot and constrain the radius of the components to R-1 = 10.3 +/- 1.3 R-circle dot and R-2 = 7.8 +/- 1.7 R-circle dot. We also report the results of an XMM-Newton monitoring of the HD 152218 X-ray emission throughout its orbital motion. The averaged X-ray spectrum is relatively soft and it is well reproduced by a 2-T optically thin thermal plasma model with component temperatures about 0.3 and 0.7 keV. The system presents an increase of its X-ray flux by about 30% near apastron compared to periastron, which is interpreted as the signature of an ongoing wind-wind interaction process occurring within the wind acceleration region. (C) 2007 Elsevier B.V. All rights reserved. [less ▲]

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See detailMassive Depletion of Bovine Leukemia Virus Proviral Clones Located in Genomic Transcriptionally Active Sites During Primary Infection
Gillet, Nicolas ULg; Gutiérrez, Gerónimo; Rodriguez, Sabrina ULg et al

in PLoS Pathogens (2013), 9(10),

Deltaretroviruses such as human T-lymphotropic virus type 1 (HTLV-1) and bovine leukemia virus (BLV) induce a persistent infection generally asymptomatic but can also lead to leukemia or lymphoma. These ... [more ▼]

Deltaretroviruses such as human T-lymphotropic virus type 1 (HTLV-1) and bovine leukemia virus (BLV) induce a persistent infection generally asymptomatic but can also lead to leukemia or lymphoma. These viruses replicate by infecting new lymphocytes (i.e. the infectious cycle) or via clonal expansion of the infected cells (mitotic cycle). The relative importance of these two cycles in viral replication varies during infection. The majority of infected clones are created early before the onset of an efficient immune response. Later on, the main replication route is mitotic expansion of pre-existing infected clones. Due to the paucity of available samples and for ethical reasons, only scarce data is available on early infection by HTLV-1. Therefore, we addressed this question in a comparative BLV model. We used high-throughput sequencing to map and quantify the insertion sites of the provirus in order to monitor the clonality of the BLV-infected cells population (i.e. the number of distinct clones and abundance of each clone). We found that BLV propagation shifts from cell neoinfection to clonal proliferation in about 2 months from inoculation. Initially, BLV proviral integration significantly favors transcribed regions of the genome. Negative selection then eliminates 97% of the clones detected at seroconversion and disfavors BLV-infected cells carrying a provirus located close to a promoter or a gene. Nevertheless, among the surviving proviruses, clone abundance positively correlates with proximity of the provirus to a transcribed region. Two opposite forces thus operate during primary infection and dictate the fate of long term clonal composition: (1) initial integration inside genes or promoters and (2) host negative selection disfavoring proviruses located next to transcribed regions. The result of this initial response will contribute to the proviral load set point value as clonal abundance will benefit from carrying a provirus in transcribed regions. [less ▲]

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See detailMassive Depletion of Bovine Leukemia Virus Proviral Clones Located in Genomic Transcriptionally Active Sites During Primary Infection
Gillet, Nicolas ULg; geronimo, gutierrez; rodriguez, sabrina et al

Poster (2014, April)

Deltaretroviruses such as human T-lymphotropic virus type 1 (HTLV-1) and bovine leukemia virus (BLV) induce a persistent infection generally asymptomatic but can also lead to leukemia or lymphoma. These ... [more ▼]

Deltaretroviruses such as human T-lymphotropic virus type 1 (HTLV-1) and bovine leukemia virus (BLV) induce a persistent infection generally asymptomatic but can also lead to leukemia or lymphoma. These viruses replicate by infecting new lymphocytes (i.e. the infectious cycle) or via clonal expansion of the infected cells (mitotic cycle). The relative importance of these two cycles in viral replication varies during infection. The majority of infected clones are created early before the onset of an efficient immune response. Later on, the main replication route is mitotic expansion of pre-existing infected clones. Due to the paucity of available samples and for ethical reasons, only scarce data is available on early infection by HTLV-1. Therefore, we addressed this question in a comparative BLV model. We used high-throughput sequencing to map and quantify the insertion sites of the provirus in order to monitor the clonality of the BLV-infected cells population (i.e. the number of distinct clones and abundance of each clone). We found that BLV propagation shifts from cell neoinfection to clonal proliferation in about 2 months from inoculation. Initially, BLV proviral integration significantly favors transcribed regions of the genome. Negative selection then eliminates 97% of the clones detected at seroconversion and disfavors BLV-infected cells carrying a provirus located close to a promoter or a gene. Nevertheless, among the surviving proviruses, clone abundance positively correlates with proximity of the provirus to a transcribed region. Two opposite forces thus operate during primary infection and dictate the fate of long term clonal composition: (1) initial integration inside genes or promoters and (2) host negative selection disfavoring proviruses located next to transcribed regions. The result of this initial response will contribute to the proviral load set point value as clonal abundance will benefit from carrying a provirus in transcribed regions. [less ▲]

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See detailMassive Depletion of Bovine Leukemia Virus Proviral Clones Located in Genomic Transcriptionally Active Sites During Primary Infection
Gillet, Nicolas ULg; Gutiérrez, Gerónimo; Rodriguez, Sabrina et al

Conference (2013, June 29)

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See detailMassive Ketonuria During Sedation with Propofol in a 12 Year Old Girl with Severe Head Trauma
Canivet, Jean-Luc ULg; Gustad, K.; Leclercq, P. et al

in Acta Anaesthesiologica Belgica (1994), 45(1), 19-22

Severe ketonuria developed during sedation with propofol in a 12 year old girl with brain injury. Deep sedation with propofol (5.1 mg/kg/h) was required because of agitation and severe intracranial ... [more ▼]

Severe ketonuria developed during sedation with propofol in a 12 year old girl with brain injury. Deep sedation with propofol (5.1 mg/kg/h) was required because of agitation and severe intracranial hypertension; as a part of our management protocol, glucose intake was restricted to 5 Kcal/h. After 18 hours of propofol infusion there was intense ketonuria (8+ by Ketostix) without any evidence of metabolic acidosis (pH, HCO3- and anion gap were within normal values). At this time, indirect calorimetry (Deltatrac) confirmed that energy expenditure was principally based on fat consumption (70% of energy expenditure). Lowering the propofol infusion rate and increasing glucose intake reduced fat consumption to 39% within 8 hours: at this time, Ketostix was negative for ketone bodies. This case illustrates a potential risk of ketonuria during prolonged sedation with propofol (a 10% solution of intralipid), particularly if glucose intake is restricted. Monitoring urinary ketone bodies is recommended under these circumstances. [less ▲]

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See detailMassive Non-Thermal Radio Emitters: New Data and their Modeling
Volpi, D.; Blomme, R.; De Becker, Michaël ULg et al

in Astronomical Society of the Pacific Conference Series (2013, January 01)

During recent years some non-thermal radio emitting OB stars have been discovered to be binary or multiple systems. The non-thermal emission is due to synchrotron radiation that is emitted by electrons ... [more ▼]

During recent years some non-thermal radio emitting OB stars have been discovered to be binary or multiple systems. The non-thermal emission is due to synchrotron radiation that is emitted by electrons accelerated up to high energies. The electron acceleration occurs at the strong shocks created by the collision of radiatively-driven winds. Here we summarize the available radio data and more recent observations for the binary Cyg OB2 No. 9. We also show a new emission model which is being developed to compare the theoretical total radio flux and the spectral index with the observed radio light curves. This comparison will be useful in order to solve fundamental questions, such as the determination of the stellar mass-loss rates, which are perturbed by clumping. [less ▲]

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See detailMassive non-thermal radio emitters: new data and their modelling
Volpi, D.; Blomme, R.; De Becker, Michaël ULg et al

Poster (2011)

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See detailA massive parsec-scale dust ring nebula around the yellow hypergiant Hen 3-1379
Hutsemekers, Damien ULg; Cox, N. L. J.; Vamvatira-Nakou, Chloi ULg

in Astronomy and Astrophysics (2013), 552

On the basis of far-infrared images obtained by the Herschel Space Observatory, we report the discovery of a large and massive dust shell around the yellow hypergiant Hen 3-1379. The nebula appears as a ... [more ▼]

On the basis of far-infrared images obtained by the Herschel Space Observatory, we report the discovery of a large and massive dust shell around the yellow hypergiant Hen 3-1379. The nebula appears as a detached ring of 1 pc diameter which contains 0.17 M[SUB]&sun;[/SUB] of dust. We estimate the total gas mass to be 7 M[SUB]&sun;[/SUB], ejected some 1.6 × 10[SUP]4[/SUP] years ago. The ring nebula is very similar to nebulae found around luminous blue variables (LBVs) except it is not photoionized. We argued that Hen 3-1379 is in a pre-LBV stage, providing direct evidence that massive LBV ring nebulae can be ejected during the red supergiant phase. [less ▲]

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See detailMassive renal and adrenal calcifications in a young dialysis patient with familial Mediterranean fever
Delanaye, Pierre ULg; Krzesinski, Jean-Marie ULg

in Nephrology Dialysis Transplantation (2005), 20(1), 238-238

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See detailThe massive runaway stars HD 14633 and HD 15137
Boyajian, T. S.; Beaulieu, T. D.; Gies, D. R. et al

in Astrophysical Journal (2005), 621(2, Part 1), 978-984

We present results from a radial velocity study of two runaway O-type stars, HD14633 (ON8.5V) and HD 15137 [O9.5 III(n)]. We find that HD 14633 is a single-lined spectroscopic binary with an orbital ... [more ▼]

We present results from a radial velocity study of two runaway O-type stars, HD14633 (ON8.5V) and HD 15137 [O9.5 III(n)]. We find that HD 14633 is a single-lined spectroscopic binary with an orbital period of 15.4083 days. The second target, HD 15137, is a radial velocity variable and a possible single-lined spectroscopic binary with a period close to 1 month. Both binaries have large eccentricity, small semiamplitude, and a small mass function. We show the trajectories of the stars in the sky based on an integration of motion in the Galactic potential, and we suggest that both stars were ejected from the vicinity of the open cluster NGC 654 in the Perseus spiral arm. The binary orbital parameters and runaway velocities are consistent with the idea that both these stars were ejected by supernova explosions in binaries and that they host neutron star companions. We find that the time of flight since ejection is longer than the predicted evolutionary timescales for the stars. This discrepancy may indicate that the stars have a lower mass than normally associated with their spectral classifications, that they were rejuvenated by mass transfer prior to the supernova, or that their lives have been extended through rapid rotation. [less ▲]

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See detailThe massive star binary fraction in young open clusters - I. NGC 6231 revisited
Sana, H.; Gosset, Eric ULg; Nazé, Yaël ULg et al

in Monthly Notices of the Royal Astronomical Society (2008), 386(1), 447-460

We present the results of a long-term high-resolution spectroscopy campaign on the O-type stars in NGC 6231. We revise the spectral classification and multiplicity of these objects and we constrain the ... [more ▼]

We present the results of a long-term high-resolution spectroscopy campaign on the O-type stars in NGC 6231. We revise the spectral classification and multiplicity of these objects and we constrain the fundamental properties of the O-star population. Almost three quarters of the O-type stars in the cluster are members of a binary system. The minimum binary fraction is 0.63, with half the O-type binaries having an orbital period of the order of a few days. The eccentricities of all the short-period binaries are revised downward, and henceforth match a normal period-eccentricity distribution. The mass ratio distribution shows a large preference for O + OB binaries, ruling out the possibility that, in NGC 6231, the companion of an O-type star is randomly drawn from a standard initial mass function. Obtained from a complete and homogeneous population of O-type stars, our conclusions provide interesting observational constraints to be confronted with the formation and early evolution theories of O-stars. [less ▲]

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See detailThe massive star binary fraction in young open clusters - II. NGC6611 (Eagle Nebula)
Sana, H.; Gosset, Eric ULg; Evans, C. J.

in Monthly Notices of the Royal Astronomical Society (2009), 400

Based on a set of over 100 medium- to high-resolution optical spectra collected from 2003 to 2009, we investigate the properties of the O-type star population in NGC6611 in the core of the Eagle Nebula ... [more ▼]

Based on a set of over 100 medium- to high-resolution optical spectra collected from 2003 to 2009, we investigate the properties of the O-type star population in NGC6611 in the core of the Eagle Nebula (M16). Using a much more extended data set than previously available, we revise the spectral classification and multiplicity status of the nine O-type stars in our sample. We confirm two suspected binaries and derive the first SB2 orbital solutions for two systems. We further report that two other objects are displaying a composite spectrum, suggesting possible long-period binaries. Our analysis is supported by a set of Monte Carlo simulations, allowing us to estimate the detection biases of our campaign and showing that the latter do not affect our conclusions. The absolute minimal binary fraction in our sample is f[SUB]min[/SUB] = 0.44 but could be as high as 0.67 if all the binary candidates are confirmed. As in NGC6231 (see Paper I), up to 75 per cent of the O star population in NGC6611 are found in an O+OB system, thus implicitly excluding random pairing from a classical IMF as a process to describe the companion association in massive binaries. No statistical difference could be further identified in the binary fraction, mass-ratio and period distributions between NGC6231 and NGC 6611, despite the difference in age and environment of the two clusters. [less ▲]

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See detailThe massive star binary fraction in young open clusters - III. IC 2944 and the Cen OB2 association
Sana, H.; James, G.; Gosset, Eric ULg

in Monthly Notices of the Royal Astronomical Society (2011), 416

Using an extended set of multi-epoch high-resolution high signal-to-noise ratio optical spectra, we readdress the multiplicity properties of the O-type stars in IC 2944 and in the Cen OB2 association. We ... [more ▼]

Using an extended set of multi-epoch high-resolution high signal-to-noise ratio optical spectra, we readdress the multiplicity properties of the O-type stars in IC 2944 and in the Cen OB2 association. We present new evidence of binarity for five objects and we confirm the multiple nature of another two. We derive the first orbital solutions for HD 100099, HD 101436 and HD 101190 and we provide additional support for HD 101205 being a quadruple system. The minimal spectroscopic binary fraction in our sample is f[SUB]min[/SUB]= 0.57. Using numerical simulations, we show that the detection rate of our observational campaign is close to 90 per cent, leaving thus little room for undetected spectroscopic binary systems. The statistical properties of the O-star population in IC 2944 are similar, within the uncertainties, to the results obtained in the earlier papers in this series despite the fact that sample size effects limit the significance of the comparison. Using newly derived spectroscopic parallaxes, we reassess the distance to IC 2944 and obtained 2.3 ± 0.3 kpc, in agreement with previous studies. We also confirm that, as far as the O stars are concerned, the IC 2944 cluster is most likely a single entity. [less ▲]

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See detailMassive stars and emission-line stars with GAIA
Blomme, Ronny; Frémat, Y.; Lobel, Alex et al

Poster (2009)

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See detailMassive Stars and High-Energy Emission in OB Associations
Rauw, Grégor ULg; Nazé, Yaël ULg; Blomme, Ronny et al

Book (2005)

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See detailMassive Stars in the Gaia-ESO Survey
Blomme, Ronny; Fremat, Yves; Lobel, Alex et al

in Massive Stars: From alpha to Omega (2013, June 01)

The Gaia-ESO Survey (GES) is an ambitious project to study the formation and evolution of the Milky Way and its stellar populations. It is led by Gerry Gilmore and Sofia Randich and includes about 350 Co ... [more ▼]

The Gaia-ESO Survey (GES) is an ambitious project to study the formation and evolution of the Milky Way and its stellar populations. It is led by Gerry Gilmore and Sofia Randich and includes about 350 Co-Investigators. During 300 nights (spread over 5 years) of order 10^5 Giraffe spectra and 10^4 UVES spectra will be taken. As part of the survey, about 13 clusters will be observed that were chosen specifically for their massive-star content. We report on the preliminary analysis of GES data from two such clusters: NGC 3293 and NGC 6705. We determine stellar parameters for the B-type stars in NGC 3293 and compare the A-type stars population between the two clusters. We also use a repeat observation to study binarity and use the radial velocity information to study cluster membership in NGC 3293. We also list our plans for future observations, which include the Carina nebula region. [less ▲]

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See detailMassive stars, a lifetime of influence
Nazé, Yaël ULg

Poster (2010)

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See detailMast cells: potential positive and negative roles in tumor biology.
Marichal, Thomas ULg; Tsai, Mindy; Galli, Stephen J.

in Cancer Immunology Research (2013), 1

Mast cells are immune cells that reside in virtually all vascularized tissues. Upon activation by diverse mechanisms, mast cells can secrete a broad array of biologically active products that either are ... [more ▼]

Mast cells are immune cells that reside in virtually all vascularized tissues. Upon activation by diverse mechanisms, mast cells can secrete a broad array of biologically active products that either are stored in the cytoplasmic granules of the cells (e.g., histamine, heparin, various proteases) or are produced de novo upon cell stimulation (e.g., prostaglandins, leukotrienes, cytokines, chemokines, and growth factors). Mast cells are best known for their effector functions during anaphylaxis and acute IgE-associated allergic reactions, but they also have been implicated in a wide variety of processes that maintain health or contribute to disease. There has been particular interest in the possible roles of mast cells in tumor biology. In vitro studies have shown that mast cells have the potential to influence many aspects of tumor biology, including tumor development, tumor-induced angiogenesis, and tissue remodeling, and the shaping of adaptive immune responses to tumors. Yet, the actual contributions of mast cells to tumor biology in vivo remain controversial. Here, we review some basic features of mast cell biology with a special emphasis on those relevant to their potential roles in tumors. We discuss how using in vivo tumor models in combination with models in which mast cell function can be modulated has implicated mast cells in the regulation of host responses to tumors. Finally, we summarize data from studies of human tumors that suggest either beneficial or detrimental roles for mast cells in tumors. [less ▲]

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