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Search Results: 1 - 10 of 1076 matches for " Heidi Noels "
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A Theoretical Framework for Soft-Information-Based Synchronization in Iterative (Turbo) Receivers
Noels Nele,Lottici Vincenzo,Dejonghe Antoine,Steendam Heidi
EURASIP Journal on Wireless Communications and Networking , 2005,
Abstract: This contribution considers turbo synchronization, that is to say, the use of soft data information to estimate parameters like carrier phase, frequency, or timing offsets of a modulated signal within an iterative data demodulator. In turbo synchronization, the receiver exploits the soft decisions computed at each turbo decoding iteration to provide a reliable estimate of some signal parameters. The aim of our paper is to show that such “turbo-estimation” approach can be regarded as a special case of the expectation-maximization (EM) algorithm. This leads to a general theoretical framework for turbo synchronization that allows to derive parameter estimation procedures for carrier phase and frequency offset, as well as for timing offset and signal amplitude. The proposed mathematical framework is illustrated by simulation results reported for the particular case of carrier phase and frequency offsets estimation of a turbo-coded 16-QAM signal.
A Theoretical Framework for Soft-Information-Based Synchronization in Iterative (Turbo) Receivers
Noels Nele,Lottici Vincenzo,Dejonghe Antoine,Steendam Heidi
EURASIP Journal on Wireless Communications and Networking , 2005,
Abstract: This contribution considers turbo synchronization, that is to say, the use of soft data information to estimate parameters like carrier phase, frequency, or timing offsets of a modulated signal within an iterative data demodulator. In turbo synchronization, the receiver exploits the soft decisions computed at each turbo decoding iteration to provide a reliable estimate of some signal parameters. The aim of our paper is to show that such "turbo-estimation" approach can be regarded as a special case of the expectation-maximization (EM) algorithm. This leads to a general theoretical framework for turbo synchronization that allows to derive parameter estimation procedures for carrier phase and frequency offset, as well as for timing offset and signal amplitude. The proposed mathematical framework is illustrated by simulation results reported for the particular case of carrier phase and frequency offsets estimation of a turbo-coded 16-QAM signal.
The Dark Side of EGFP: Defective Polyubiquitination
Mathijs Baens, Heidi Noels, Vicky Broeckx, Sofie Hagens, Sabine Fevery, An D. Billiau, Hugo Vankelecom, Peter Marynen
PLOS ONE , 2006, DOI: 10.1371/journal.pone.0000054
Abstract: Enhanced Green Fluorescent Protein (EGFP) is the most commonly used live cell reporter despite a number of conflicting reports that it can affect cell physiology. Thus far, the precise mechanism of GFP-associated defects remained unclear. Here we demonstrate that EGFP and EGFP fusion proteins inhibit polyubiquitination, a posttranslational modification that controls a wide variety of cellular processes, like activation of kinase signalling or protein degradation by the proteasome. As a consequence, the NF-κB and JNK signalling pathways are less responsive to activation, and the stability of the p53 tumour suppressor is enhanced in cell lines and in vivo. In view of the emerging role of polyubiquitination in the regulation of numerous cellular processes, the use of EGFP as a live cell reporter should be carefully considered.
Semi-convection: What is the underlying physical context?
Arlette Noels
Physics , 2015, DOI: 10.1007/978-3-642-33380-4_10
Abstract: Stellar conditions leading to a possible semi-convective mixing are discussed in three relevant cases: (1) low mass MS stars in which the CNO cycle takes progressively the lead over the PP chain due to the increase in temperature as core hydrogen burning proceeds, (2) massive MS stars which experience a large contri- bution of the radiation pressure to the total pressure and (3) core helium burning stars for which the production of carbon in the core increases the opacity. A short discussion of semi-convection in terms of instability of non radial modes follows.
Auto-Ubiquitination-Induced Degradation of MALT1-API2 Prevents BCL10 Destabilization in t(11;18)(q21;q21)-Positive MALT Lymphoma
Heidi Noels, Riet Somers, Hongxiang Liu, Hongtao Ye, Ming-Qing Du, Christiane De Wolf-Peeters, Peter Marynen, Mathijs Baens
PLOS ONE , 2009, DOI: 10.1371/journal.pone.0004822
Abstract: Background The translocation t(11;18)(q21;q21) is the most frequent chromosomal aberration associated with MALT lymphoma and results in constitutive NF-κB activity via the expression of an API2-MALT1 fusion protein. The properties of the reciprocal MALT1-API2 were never investigated as it was reported to be rarely transcribed. Principal Findings Our data indicate the presence of MALT1-API2 transcripts in the majority of t(11;18)(q21;q21)-positive MALT lymphomas. Based on the breakpoints in the MALT1 and API2 gene, the MALT1-API2 protein contains the death domain and one or both immunoglobulin-like domains of MALT1 (~90% of cases) - mediating the possible interaction with BCL10 - fused to the RING domain of API2. Here we show that this RING domain enables MALT1-API2 to function as an E3 ubiquitin ligase for BCL10, inducing its ubiquitination and proteasomal degradation in vitro. Expression of MALT1-API2 transcripts in t(11;18)(q21;q21)-positive MALT lymphomas was however not associated with a reduction of BCL10 protein levels. Conclusion As we observed MALT1-API2 to be an efficient target of its own E3 ubiquitin ligase activity, our data suggest that this inherent instability of MALT1-API2 prevents its accumulation and renders a potential effect on MALT lymphoma development via destabilization of BCL10 unlikely.
Uncertainties in models of stellar structure and evolution
Arlette Noels,Angela Bragaglia
Physics , 2014, DOI: 10.1007/978-3-319-10993-0_19
Abstract: Numerous physical aspects of stellar physics have been presented in Ses- sion 2 and the underlying uncertainties have been tentatively assessed. We try here to highlight some specific points raised after the talks and during the general discus- sion at the end of the session and eventually at the end of the workshop. A table of model uncertainties is then drawn with the help of the participants in order to give the state of the art in stellar modeling uncertainties as of July 2013.
Openness in Scandinavian Classrooms: Student Perceptions of Teaching Practices and High Achievers of Civic Knowledge  [PDF]
Lihong Huang, Heidi Biseth
Creative Education (CE) , 2016, DOI: 10.4236/ce.2016.75075
Abstract: In this paper, we explore how teaching practices in classrooms influence students’ civic knowledge achievement in three Scandinavian countries: Denmark, Norway, and Sweden. Using data from the 2009 International Civic and Citizenship Education Study (ICCS), our investigation focuses on the measures of “open classroom climate”, which include seven items that ask students how often they experience each of the seven teaching practices during regular lessons. From the students’ perspective of teaching practices in the classroom, we hypothesize and assume that there should be a balanced combination of classroom practices where each method/activity carries a different weight or level of importance. Applying logistic regression analysis, we assess the effect of each of the practices on the probability with which a student becomes a high achiever of civic knowledge (as represented by odds ratios). Our results show both similarities and differences in the combinations of classroom practices that have contributed to students’ high civic knowledge achievement in the three Scandinavian countries. Our findings provide useful messages to teachers in the classroom, and they also have implications for teacher education and research.
Asteroseismology of red giant stars: The potential of dipole modes
Montalbán J.,Noels A.
EPJ Web of Conferences , 2013, DOI: 10.1051/epjconf/20134303002
Abstract: Since the detection of non-radial solar-like oscillation modes in red giants with the CoRoT satellite, the interest in the asteroseismic properties of red giants and the link with their global properties and internal structure is increasing. Moreover, more and more precise data are being collected with the space-based telescopes CoRoT and Kepler. Particularly relevant has been the detection of mixed modes in a large number of G-K red giants. In this contribution we discuss the potential of these dipole mixed modes to provide information on core extra-mixing and transport of angular momentum.
Bone Marrow-Specific Knock-In of a Non-Activatable Ikkα Kinase Mutant Influences Haematopoiesis but Not Atherosclerosis in Apoe-Deficient Mice
Pathricia V. Tilstam, Marion J. Gijbels, Mohamed Habbeddine, Céline Cudejko, Yaw Asare, Wendy Theelen, Baixue Zhou, Yvonne D?ring, Maik Drechsler, Lukas Pawig, Sakine Simsekyilmaz, Rory R. Koenen, Menno P. J. de Winther, Toby Lawrence, Jürgen Bernhagen, Alma Zernecke, Christian Weber, Heidi Noels
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0087452
Abstract: Background The Ikkα kinase, a subunit of the NF-κB-activating IKK complex, has emerged as an important regulator of inflammatory gene expression. However, the role of Ikkα-mediated phosphorylation in haematopoiesis and atherogenesis remains unexplored. In this study, we investigated the effect of a bone marrow (BM)-specific activation-resistant Ikkα mutant knock-in on haematopoiesis and atherosclerosis in mice. Methods and Results Apolipoprotein E (Apoe)-deficient mice were transplanted with BM carrying an activation-resistant Ikkα gene (IkkαAA/AAApoe?/?) or with Ikkα+/+Apoe?/? BM as control and were fed a high-cholesterol diet for 8 or 13 weeks. Interestingly, haematopoietic profiling by flow cytometry revealed a significant decrease in B-cells, regulatory T-cells and effector memory T-cells in IkkαAA/AAApoe?/? BM-chimeras, whereas the naive T-cell population was increased. Surprisingly, no differences were observed in the size, stage or cellular composition of atherosclerotic lesions in the aorta and aortic root of IkkαAA/AAApoe?/? vs Ikkα+/+Apoe?/? BM-transplanted mice, as shown by histological and immunofluorescent stainings. Necrotic core sizes, apoptosis, and intracellular lipid deposits in aortic root lesions were unaltered. In vitro, BM-derived macrophages from IkkαAA/AAApoe?/? vs Ikkα+/+Apoe?/? mice did not show significant differences in the uptake of oxidized low-density lipoproteins (oxLDL), and, with the exception of Il-12, the secretion of inflammatory proteins in conditions of Tnf-α or oxLDL stimulation was not significantly altered. Furthermore, serum levels of inflammatory proteins as measured with a cytokine bead array were comparable. Conclusion Our data reveal an important and previously unrecognized role of haematopoietic Ikkα kinase activation in the homeostasis of B-cells and regulatory T-cells. However, transplantation of IkkαAA mutant BM did not affect atherosclerosis in Apoe?/? mice. This suggests that the diverse functions of Ikkα in haematopoietic cells may counterbalance each other or may not be strong enough to influence atherogenesis, and reveals that targeting haematopoietic Ikkα kinase activity alone does not represent a therapeutic approach.
The Creation and Physiological Relevance of Divergent Hydroxylation Patterns in the Flavonoid Pathway
Heidi Halbwirth
International Journal of Molecular Sciences , 2010, DOI: 10.3390/ijms11020595
Abstract: Flavonoids and biochemically-related chalcones are important secondary metabolites, which are ubiquitously present in plants and therefore also in human food. They fulfill a broad range of physiological functions in planta and there are numerous reports about their physiological relevance for humans. Flavonoids have in common a basic C 6-C 3-C 6 skeleton structure consisting of two aromatic rings (A and B) and a heterocyclic ring (C) containing one oxygen atom, whereas chalcones, as the intermediates in the formation of flavonoids, have not yet established the heterocyclic C-ring. Flavonoids are grouped into eight different classes, according to the oxidative status of the C-ring. The large number of divergent chalcones and flavonoid structures is from the extensive modification of the basic molecules. The hydroxylation pattern influences physiological properties such as light absorption and antioxidative activity, which is the base for many beneficial health effects of flavonoids. In some cases antiinfective properties are also effected.
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