Université de Namur

About: Université de Namur is a education organization based out in Namur, Belgium. It is known for research contribution in the topics: Carbon nanotube & Population. The organization has 3924 authors who have published 9570 publications receiving 278750 citations. The organization is also known as: Facultés universitaires Notre-Dame de la Paix & FUNDP.

Carbon nanotubes: properties and application

Abstract: Carbon nanotubes are unique tubular structures of nanometer diameter and large length/diameter ratio. The nanotubes may consist of one up to tens and hundreds of concentric shells of carbons with adjacent shells separation of ∼0.34 nm. The carbon network of the shells is closely related to the honeycomb arrangement of the carbon atoms in the graphite sheets. The amazing mechanical and electronic properties of the nanotubes stem in their quasi-one-dimensional (1D) structure and the graphite-like arrangement of the carbon atoms in the shells. Thus, the nanotubes have high Young’s modulus and tensile strength, which makes them preferable for composite materials with improved mechanical properties. The nanotubes can be metallic or semiconducting depending on their structural parameters. This opens the ways for application of the nanotubes as central elements in electronic devices including field-effect transistors (FET), single-electron transistors and rectifying diodes. Possibilities for using of the nanotubes as high-capacity hydrogen storage media were also considered. This report is intended to summarize some of the major achievements in the field of the carbon nanotube research both experimental and theoretical in connection with the possible industrial applications of the nanotubes.

Seven temperate terrestrial planets around the nearby ultracool dwarf star TRAPPIST-1

Abstract: One aim of modern astronomy is to detect temperate, Earth-like exoplanets that are well suited for atmospheric characterization. Recently, three Earth-sized planets were detected that transit (that is, pass in front of) a star with a mass just eight per cent that of the Sun, located 12 parsecs away. The transiting configuration of these planets, combined with the Jupiter-like size of their host star—named TRAPPIST-1—makes possible in-depth studies of their atmospheric properties with present-day and future astronomical facilities. Here we report the results of a photometric monitoring campaign of that star from the ground and space. Our observations reveal that at least seven planets with sizes and masses similar to those of Earth revolve around TRAPPIST-1. The six inner planets form a near-resonant chain, such that their orbital periods (1.51, 2.42, 4.04, 6.06, 9.1 and 12.35 days) are near-ratios of small integers. This architecture suggests that the planets formed farther from the star and migrated inwards. Moreover, the seven planets have equilibrium temperatures low enough to make possible the presence of liquid water on their surfaces.

An overview of bilevel optimization

Abstract: This paper is devoted to bilevel optimization, a branch of mathematical programming of both practical and theoretical interest. Starting with a simple example, we proceed towards a general formulation. We then present fields of application, focus on solution approaches, and make the connection with MPECs (Mathematical Programs with Equilibrium Constraints).

Protocols to detect senescence-associated beta-galactosidase (SA-betagal) activity, a biomarker of senescent cells in culture and in vivo.

Abstract: Normal cells can permanently lose the ability to proliferate when challenged by potentially oncogenic stress, a process termed cellular senescence. Senescence-associated beta-galactosidase (SA-betagal) activity, detectable at pH 6.0, permits the identification of senescent cells in culture and mammalian tissues. Here we describe first a cytochemical protocol suitable for the histochemical detection of individual senescent cells both in culture and tissue biopsies. The second method is based on the alkalinization of lysosomes, followed by the use of 5-dodecanoylaminofluorescein di-beta-D-galactopyranoside (C12FDG), a fluorogenic substrate for betagal activity. The cytochemical method takes about 30 min to execute, and several hours to a day to develop and score. The fluorescence methods take between 4 and 8 h to execute and can be scored in a single day. The cytochemical method is applicable to tissue sections and requires simple reagents and equipment. The fluorescence-based methods have the advantages of being more quantitative and sensitive.