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See detailCharacterization of the discoidal complexes formed between apoA-I-CNBr fragments and phosphatidylcholine.
Vanloo, B.; Morrison, J.; Fidge, N. et al

in Journal of Lipid Research (1991), 32(8), 1253-64

The structure, composition, and physico-chemical properties of lipid-protein complexes generated between dimyristoylphosphatidylcholine (DPMC) and the CNBr fragments of human apoA-I were studied. The ... [more ▼]

The structure, composition, and physico-chemical properties of lipid-protein complexes generated between dimyristoylphosphatidylcholine (DPMC) and the CNBr fragments of human apoA-I were studied. The fragments were separated by high performance liquid chromatography and purified on a reversed-phase column. The complexes with DMPC were isolated on a Superose column; their dimensions were obtained by gradient gel electrophoresis and by electron microscopy. The secondary structure of the protein in the complexes was studied both by circular dichroism and by attenuated total reflection infrared spectroscopy. The fragments 1 and 4 of apoA-I, containing, respectively, two and three amphipathic helices, recombined with the phospholipid to generate discoidal particles with sizes similar to that of apoA-I- and apoA-II-DMPC complexes. The infrared measurements indicated that in all complexes the apolipoprotein helical segments were oriented parallel to the phospholipid acyl chains and that the protein was located around the edges of the discs. Computer modelling of the complexes based on energy minimization techniques proposed a model for these particles in agreement with the dimensions measured experimentally. In conclusion, we propose that apoA-I and its longest CNBr fragments are able to generate discoidal particles with DMPC, with apolipoprotein helical segments oriented parallel to the acyl chains of the phospholipids. [less ▲]

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See detailCharacterization of the erosive power of the suspension used within the framework of accelerated wear tests of spraying nozzles.
Loyen, S.; Huyghebaert, B.; Debouche, Charles ULg et al

in Mededelingen van de Faculteit Landbouwkundige en Toegepaste Biologische Wetenschappen (Rijksuniversiteit te Gent) (2000), 65(2b), 907-918

The study concerns the application techniques of agrochemical products and especially focuses on the wear of spraying nozzles. This one leads to a modification of the spraying characteristics and the ... [more ▼]

The study concerns the application techniques of agrochemical products and especially focuses on the wear of spraying nozzles. This one leads to a modification of the spraying characteristics and the homogeneity of distribution deteriorates. An accelerated wear process of nozzles is defined by the standard ISO 5682-1, which makes it possible to compare the wear resistance of the different nozzles available on the market. In order to accelerate the process, an erosive suspension is used in the test rig, but this suspension looses its characteristics during the utilisation time. This is the reason why a system measuring continuously the erosive power has been set up. This system is validated by different discontinuous measurement and the correlation observed have a coefficient of about 0,99. From the signal detected by the new device, two calculations have been carried out. A first one determining continuously the total wear quantity of the nozzles. A second one identifying continuously the erosive power of the suspension. On the one hand, we obtain a basis allowing to compare the wear resistance of nozzles and on the other hand, a parameter indicating the appropriate time to change the suspension. [less ▲]

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See detailCharacterization of the gaseous companion κ Andromedae b. New Keck and LBTI high-contrast observations
Bonnefoy, M.; Currie, T.; Marleau, G.-D. et al

in Astronomy and Astrophysics (2014), 562

Context. We previously reported the direct detection of a low-mass companion at a projected separation of 55 ± 2 AU around the B9-type star κ Andromedae. The properties of the system (mass ratio ... [more ▼]

Context. We previously reported the direct detection of a low-mass companion at a projected separation of 55 ± 2 AU around the B9-type star κ Andromedae. The properties of the system (mass ratio, separation) make it a benchmark for understanding the formation and evolution of gas giant planets and brown dwarfs on wide orbits. <BR /> Aims: We present new angular differential imaging (ADI) images of the system at 2.146 (K[SUB]s[/SUB]), 3.776 (L'), 4.052 (NB_4.05), and 4.78 μm (M') obtained with Keck/NIRC2 and LBTI/LMIRCam, as well as more accurate near-infrared photometry of the star with the MIMIR instrument. We aim to determine the near-infrared spectral energy distribution of the companion and use it to characterize the object. <BR /> Methods: We used analysis methods adapted to ADI to extract the companion flux. We compared the photometry of the object to reference young, and old objects and to a set of seven PHOENIX-based atmospheric models of cool objects accounting for the formation of dust. We used evolutionary models to derive mass estimates considering a wide range of plausible initial conditions. Finally, we used dedicated formation models to discuss the possible origin of the companion. <BR /> Results: We derive a more accurate J = 15.86 ± 0.21, H = 14.95 ± 0.13, K[SUB]s[/SUB] = 14.32 ± 0.09 mag for κ And b. We detect the companion in all our high-contrast observations. We confirm previous contrasts obtained at K[SUB]s[/SUB] and L' band. We derive NB_4.05 = 13.0 ± 0.2, and M' = 13.3 ± 0.3 mag and estimate log [SUB]10[/SUB](L/L[SUB]⊙[/SUB]) = -3.76 ± 0.06. Atmospheric models yield T[SUB]eff[/SUB] = 1900[SUP]+100[/SUP][SUB]-200[/SUB] K. They do not set any constraint on the surface gravity. "Hot-start" evolutionary models predict masses of 14[SUP]+25[/SUP][SUB]-2[/SUB] M[SUB]Jup[/SUB] based on the luminosity and temperature estimates, and when considering a conservative age range for the system (30[SUP]+120[/SUP][SUB]-10[/SUB] Myr), "warm-start" evolutionary tracks constrain the mass to M ≥ 10M[SUB]Jup[/SUB]. <BR /> Conclusions: The mass of κ Andromedae b mostly falls in the brown-dwarf regime, owing to remaining uncertainties in age and in mass-luminosity models. According to the formation models, disk instability in a primordial disk may account for the position and a wide range of plausible masses of κ And b. The LBT is an international collaboration among institutions in the United States, Italy, and Germany. LBT Corporation partners are: The University of Arizona on behalf of the Arizona university system; Instituto Nazionale di Astrofisica, Italy; LBT Beteiligungsgesellschaft, Germany, representing the Max-Planck Society, the Astrophysical Institute Potsdam, and Heidelberg University; The Ohio State University, and The Research Corporation, on behalf of the University of Notre Dame, University of Minnesota, and University of Virginia.Appendices are available in electronic form at <A href="http://www.aanda.org/10.1051/0004-6361/201322119/olm">http://www.aanda.org</A> [less ▲]

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See detailCharacterization of the hot Neptune GJ 436 b with Spitzer and ground-based observations
Demory, B*-O; Gillon, Michaël ULg; Barman, T. et al

in Astronomy and Astrophysics (2007), 475

We present Spitzer Space Telescope infrared photometry of a secondary eclipse of the hot Neptune GJ 436 b. The observations were obtained using the 8-mum band of the InfraRed Array Camera (IRAC). The data ... [more ▼]

We present Spitzer Space Telescope infrared photometry of a secondary eclipse of the hot Neptune GJ 436 b. The observations were obtained using the 8-mum band of the InfraRed Array Camera (IRAC). The data spanning the predicted time of secondary eclipse show a clear flux decrement with the expected shape and duration. The observed eclipse depth of 0.58 mmag allows us to estimate a blackbody brightness temperature of T[SUB]p[/SUB] = 717 ± 35 K at 8 mum. We compare this infrared flux measurement to a model of the planetary thermal emission, and show that this model reproduces properly the observed flux decrement. The timing of the secondary eclipse confirms the non-zero orbital eccentricity of the planet, while also increasing its precision (e = 0.14 ± 0.01). Additional new spectroscopic and photometric observations allow us to estimate the rotational period of the star and to assess the potential presence of another planet. Our final secondary eclipse, photometric and Ca II H+K index time series are available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/475/1125 [less ▲]

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See detailCharacterization of the human Fc gamma RIIB gene promoter: human zinc-finger proteins (ZNF140 and ZNF91) that bind to different regions function as transcription repressors
Nishimura, Tadahiro; Narita, Tadashi; Miyazaki, Emi et al

in International Immunology (2001), 13(8), 1075-84

Expression of the human low-affinity Fc receptors for IgG (human Fc gamma RII) is differentially regulated. We report here the characterization of the promoter structure of the human Fc gamma RIIB gene ... [more ▼]

Expression of the human low-affinity Fc receptors for IgG (human Fc gamma RII) is differentially regulated. We report here the characterization of the promoter structure of the human Fc gamma RIIB gene and the isolation of the promoter region-binding proteins by a yeast one-hybrid assay. The minimal 154-bp region upstream from the transcription start site of the human Fc gamma RIIB gene was shown to possess promoter activity in a variety of cells. An electrophoretic mobility shift assay indicated that multiple nuclear factors in cell extracts bind to the two regions [F2-3 (-110 to -93) and F4-3 (-47 to -31)] of the human Fc gamma RIIB gene promoter. Mutation analysis indicated that GGGAGGAGC (-105 to -97) and AATTTGTTTGCC (-47 to -36) sequences are responsible for binding to nuclear factors respectively. By using GGGAGGAGC and AATTTGTTTGCC as bait sequences, we cloned two zinc-finger proteins (ZNF140 and ZNF91) that bind to the F2-3 and F4-3 regions within the promoter of the human Fc gamma RIIB gene respectively. When the ZNF140 and ZNF91 were transfected with reporter plasmid, both showed repressor activity with additive effects. Thus, these results indicate that these cloned ZNF140 and ZNF91 proteins function as repressors for the human Fc gamma RIIB transcription. [less ▲]

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See detailCharacterization of the IGF system and analysis of the possible molecular mechanisms leading to IGF-II overexpression in a mesothelioma.
Hodzic, D.; Delacroix, Laurence ULg; Willemsen, P. et al

in Hormone & Metabolic Research (1997), 29(11), 549-55

The expression of members of the IGF system in a mesothelioma from a patient suffering from hypoglycemia, in term placenta and HT29 colon adenocarcinoma cells were compared. Very high levels of IGF-II ... [more ▼]

The expression of members of the IGF system in a mesothelioma from a patient suffering from hypoglycemia, in term placenta and HT29 colon adenocarcinoma cells were compared. Very high levels of IGF-II mRNA and protein were detected in the mesothelioma. Moreover, half of the IGF-II protein took the high-molecular-weight form. We also analyzed the parental imprinting status and the promoter usage of the IGF-II gene. Our results showed loss of imprinting (LOI) in the mesothelioma while the imprinting was maintained in HT29 cells, expressing moderate levels of the transcript. Promoter P4 was active in the three tissues we analyzed, whereas IGF-II mRNA transcription from promoter P3 was only detected in the mesothelioma and the placenta, expressing comparably high levels of the transcript. IGF-II gene structure was identical in the analyzed tissues and cells. The type-I receptor mRNA expression was very low in the tumor. IGFBP-2, -4 and -5 mRNAs were detected in the mesothelioma, while IGFBP-2, -3 and -5 transcripts were detected in the placenta. IGFBP-1 and -6 transcripts were not detected. [less ▲]

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See detailCharacterization of the impact of tillage and nitrogen fertilization on the root development of a winter wheat crop by use of NIR hyperspectral imaging combined to chemometrics
Fraipont, Guillaume ULg; Eylenbosch, Damien ULg; Fernández Pierna, Juan Antonio et al

Poster (2016, March 16)

The objective of this study is to characterize the impact of tillage management and nitrogen fertilization on the root system development of a winter wheat crop. To reach this objective, an innovative ... [more ▼]

The objective of this study is to characterize the impact of tillage management and nitrogen fertilization on the root system development of a winter wheat crop. To reach this objective, an innovative root quantification method that combines NIR hyperspectral imaging (NIR-HSI) and chemometric tools will be applied. [less ▲]

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See detailCharacterization of the impact of tillage on the root development and distribution of crop residues of a winter wheat crop by the use of NIR hyperspectral imaging
Fraipont, Guillaume ULg; Eylenbosch, Damien ULg; Fernández Pierna, Juan Antonio et al

Poster (2016, May 20)

The objectives of the study were to show the impact of tillage and crop residues management on the distribution of crop residues and root system of a winter wheat crop in the 0-30 cm soil profile.This ... [more ▼]

The objectives of the study were to show the impact of tillage and crop residues management on the distribution of crop residues and root system of a winter wheat crop in the 0-30 cm soil profile.This poster shows the results obtained during one crop year (2011-2012). This study is allowed by a rapid and innovative method of root system quantification based on the near infrared hyperspectral Imaging. [less ▲]

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See detailCharacterization of the insulin-like growth (IGF) axis in the human thymus
Kecha, Ouafae; Achour, Imane; Martens, Henri ULg et al

in The Endocrine Society (Ed.) Proceedings of the 77th Annual Meeting of the Endocrine Society (1997)

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See detailCharacterization of the Insulin-Like Growth Factor Axis in the Human Thymus
Kecha, Ouafae; Martens, Henri ULg; Franchimont, Nathalie et al

in Journal of Neuroendocrinology (1999), 11(6), 435-40

The components of the insulin-like growth factor (IGF) axis have been investigated in the normal human thymus. Using ribonuclease protection assays (RPA), IGF-II transcripts were detected in the normal ... [more ▼]

The components of the insulin-like growth factor (IGF) axis have been investigated in the normal human thymus. Using ribonuclease protection assays (RPA), IGF-II transcripts were detected in the normal human thymus. By reverse transcriptase polymerase chain reaction (RT-PCR) analyses, promoters P3 and P4 were found to be active in the transcription of IGF2 gene within human thymic epithelial cells (TEC). No IGF-II mRNA could be detected in human lymphoid Jurkat T cells with 30 cycles of RT-PCR. By Northern blot analyses, IGFBP-2 to -6 (but not IGFBP-1) were found to be expressed in TEC with a predominance of IGFBP-4. Interestingly, Jurkat T cells only express IGFBP-2 but at high levels. The type 1 IGF receptor was detected in Jurkat T cells but not in human TEC. The identification of the components of the IGF axis within separate compartments of the human thymus adds further evidence for a role of this axis in the control of T-cell development. The precise influence of thymic IGF axis upon T-cell differentiation and immunological self-tolerance however needs to be further investigated. [less ▲]

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See detailCharacterization of the interaction between nanoformulated drugs and model lipid membranes towards improved drug delivery systems
De Battice, Laura; Frost, Rickard; Sevrin, Chantal ULg et al

Poster (2011, October)

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See detailCharacterization of the interaction between nanoformulated drugs and model lipid membranes towards improved drug delivery systems
De Battice, Laura; Frost, Rickard; Sevrin, Chantal ULg et al

Poster (2011, October 25)

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See detailCharacterization of the interaction of xylose-based bolaamphiphiles with biomimetic membrane systems
Nasir, Mehmet Nail ULg; Legrand, Vincent; Gatard, Sylvain et al

Conference (2012, July)

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See detailCharacterization of the interactions between fluoroquinolone antibiotics and lipids: a multitechnique approach.
Bensikaddour, Hayet; Fa, Nathalie; Burton, Ingrid et al

in Biophysical Journal (2008), 94(8), 3035-46

Probing drug/lipid interactions at the molecular level represents an important challenge in pharmaceutical research and membrane biophysics. Previous studies showed differences in accumulation and ... [more ▼]

Probing drug/lipid interactions at the molecular level represents an important challenge in pharmaceutical research and membrane biophysics. Previous studies showed differences in accumulation and intracellular activity between two fluoroquinolones, ciprofloxacin and moxifloxacin, that may actually result from their differential susceptibility to efflux by the ciprofloxacin transporter. In view of the critical role of lipids for the drug cellular uptake and differences observed for the two closely related fluoroquinolones, we investigated the interactions of these two antibiotics with lipids, using an array of complementary techniques. Moxifloxacin induced, to a greater extent than ciprofloxacin, an erosion of the DPPC domains in the DOPC fluid phase (atomic force microscopy) and a shift of the surface pressure-area isotherms of DOPC/DPPC/fluoroquinolone monolayer toward lower area per molecule (Langmuir studies). These effects are related to a lower propensity of moxifloxacin to be released from lipid to aqueous phase (determined by phase transfer studies and conformational analysis) and a marked decrease of all-trans conformation of acyl-lipid chains of DPPC (determined by ATR-FTIR) without increase of lipid disorder and change in the tilt between the normal and the germanium surface (also determined by ATR-FTIR). All together, differences of ciprofloxacin as compared to moxifloxacin in their interactions with lipids could explain differences in their cellular accumulation and susceptibility to efflux transporters. [less ▲]

Detailed reference viewed: 54 (2 ULg)