The multiplicity of O-type stars in NGC 2244

in Bulletin de la Societe Royale des Sciences de Liege (2011), 80

The investigation of the multiplicity of massive stars is crucial to determine a robust binary fraction but also for understanding the physical properties of these objects. In this contribution, we will ... [more ▼]

The investigation of the multiplicity of massive stars is crucial to determine a robust binary fraction but also for understanding the physical properties of these objects. In this contribution, we will present the main results from our long-term spectroscopic survey devoted to the young open cluster NGC 2244. We discuss the spectral classification, the projected rotational velocity (v sin{i}) and the multiplicity of O-stars. The stellar and wind parameters of each star, obtained using the CMFGEN atmosphere code, help us to better constrain the individual properties of these objects. Several of these stars were observed by the CoRoT satellite (SRa02) in the Asteroseismology channel. This intensive monitoring and the unprecedented quality of the light curves allow us to shed a new light on these objects. [less ▲]

A Multipotential Beta -1,6-N-Acetylglucosaminyl-Transferase Is Encoded by Bovine Herpesvirus Type 4

in Proceedings of the National Academy of Sciences of the United States of America (2000), 97(11), 5756-5761

The beta-1,6-N-acetylglucosaminyltransferase (beta1,6GnT) gene family encodes enzymes playing crucial roles in glycan synthesis. Important changes in beta1,6GnT expression are observed during development ... [more ▼]

The beta-1,6-N-acetylglucosaminyltransferase (beta1,6GnT) gene family encodes enzymes playing crucial roles in glycan synthesis. Important changes in beta1,6GnT expression are observed during development, oncogenesis, and immunodeficiency. The most characterized beta1,6GnTs in this gene family are the human (h) C2GnT-L and h-IGnT, which have core 2 [Galbeta1-->3(GlcNAcbeta1-->6)GalNAc] and I branching [GlcNAcbeta1-->3(GlcNAcbeta1-->6)Gal] activities, respectively. Recently, h-C2GnT-M was shown to be unique in forming core 2, core 4 [GlcNAcbeta1-->3(GlcNAcbeta1-->6)GalNAc], and I structures. To date, the beta1,6GnT gene family has been characterized only in mammals. Here, we describe that bovine herpesvirus type 4 (BHV-4) encodes a beta1,6GnT expressed during viral replication and exhibiting all of the core 2, core 4, and I branching activities. Sequencing of the BHV-4 genome revealed an ORF, hereafter called BORFF3-4, encoding a protein (pBORFF3-4) exhibiting 81.1%, 50.7%, and 36.6% amino acid identity with h-C2GnT-M, h-C2GnT-L, and h-IGnT, respectively. Reverse transcriptase-PCR analysis revealed that BORFF3-4 is expressed during BHV-4 replication. Expression of BORFF3-4 in Chinese hamster ovary cells directed the expression of core 2 branched oligosaccharides and I antigenic structures on the cell surface. Moreover, a soluble form of pBORFF3-4 had core 4 branching activity in addition to core 2 and I branching activities. Finally, infection of a C2GnT-negative cell line with BHV-4 induced expression of core 2 branched oligosaccharides. This study extends the beta1,6GnT gene family to a viral gene and provides a model to study the biological functions of a beta1,6GnT in the context of viral infection. [less ▲]

Multiproxy evidence of `Little Ice Age' palaeoenvironmental changes in a peat bog from northern Poland

in Holocene (2009), 19(4), 625-637

`Little Ice Age' (LIA) climatic deteriorations have been abundantly documented in various archives such as ice, lake sediments and peat bog deposits. Palaeoecological analyses of peat samples have ... [more ▼]

`Little Ice Age' (LIA) climatic deteriorations have been abundantly documented in various archives such as ice, lake sediments and peat bog deposits. Palaeoecological analyses of peat samples have identified these climatic deteriorations using a range of techniques, for example palynology, plant macrofossils, testate amoebae or carbon isotopic analyses. The use of inorganic geochemistry and the reconstruction of dust fluxes has remained a challenge in tracing the nature of LIA climatic changes. Although the idea of enhanced erosion conditions and storminess is commonly discussed, the conditions for dust deposition in peatlands over Europe during the LIA are rarely favourable, because the natural forest cover over Europe was much more important than nowadays, preventing dust deposition. This intense forest canopy masks the deposition of dust in peatlands. In northern Poland, near the Baltic shore, the S[l]owi[n]skie B[l]ota area was deforested around AD 1100, ie, just before the LIA, and therefore constitutes a key area for the reconstruction of LIA climatic change. With the support of a well-constrained chronology, climatic fluctuations are recorded in an ombrotrophic bog using inorganic geochemistry, plant macrofossils and carbon isotopic analyses. The reconstruction of LIA climatic changes is in good agreement with other records from Poland and NE Europe. However, a c. 50-year discrepancy can be observed between various records. This discrepancy is possibly due to progressive time-dependent cooling gradient from north to south Europe. [less ▲]

Multiproxy, multicore palaeoenvironmental study during the last millennium in the Misten peat bog (Hautes Fagnes, East Belgium).

Conference (2010)

Multiproxy, multicore palaeoenvironmental study during the last millennium in the Misten peat bog (Hautes Fagnes, East Belgium).

Poster (2010)

Multiqubit symmetric states with a high geometric entanglement

Poster (2010, July)

Multiradial Image Analysis in Optical Reflected Light Microscopy

in XIIIth European Congress for Microscopy (2004)

Multirisk assessment in postmenopausal women

in Osteoporosis International (2006, March), 17(Suppl.1), 112

A multiscalar quantitative approach to assess landscape dynamics and anthropogenic effects

Conference (2010)

Multiscale approach of fish responses to different types of environmental contaminations: A case study

in Science of the Total Environment (2006), 367(2-3), 715-731

In order to study the responses of wild fish to environmental contaminations, different sites (two references and three contaminated) were sampled across the Walloon hydrographical network (southern ... [more ▼]

In order to study the responses of wild fish to environmental contaminations, different sites (two references and three contaminated) were sampled across the Walloon hydrographical network (southern Belgium). The status of fish communities was characterized according to an index of biotic integrity (1131). Furthermore, population structure, reproductive parameters and biochemical assays were performed on chub (Leuciscus cephalus) as sentinel species. The results showed impaired responses in fish sampled downstream paper mill effluents (BKME), in a polychlorinated biphenyls (PCB) contaminated site, and in a river receiving pesticides (i.e. atrazine and hexachlorocyclohexane). High level of hepatic 7-ethoxyresorufin-Odeethylase (EROD) activity were evidence of direct toxicant exposure, while population structures showed unbalanced size-frequency distributions. Moreover, in the pesticide contaminated site, a higher proportion of atretic oocytes was found in females and abnormally high plasma alkali-labile phosphorus (ALP) values were noticed in males, compared to reference sites, suggesting that chubs were exposed to estrogenic compounds. IBI scores from both sites were also lower than in reference sites. On the other hand, no particular response was found in hepatic glutathione-S-transferase (GST) activities, hepatic heat-shock protein HSP70 concentrations and plasma sex steroids (estradiol-17 beta, 11-ketotestosterone and testosterone) in chubs from any sites. By using a multiparametric approach, a better understanding of response mechanisms to pollution in fish may be achieved in order to improve the ecological status of river ecosystems. (c) 2006 Elsevier B.V All rights reserved. [less ▲]