Comité national de mathématiques

editorial reviewe

Concours annuel 1952 : première question, rapport du premier commissaire

editorial reviewe

Co-doped Dy3+ and Pr3+ Ga5Ge20Sb10S65 fibers for mid-infrared broad emission

Rare earth ion doped materials are means to obtain cost-effective infrared light sources, with enough brilliance for applications such as gas sensing. Within a sulfide matrix, the simultaneous luminescence of both Pr3+ and Dy3+ in the Ga5Ge20Sb10S65 glass is reported. The use of these two rare earths is giving rise to a broad continuous luminescence in the 2.2–5.5 µm wavelength range, which could be used as a mid-infrared light source for gas-sensing applications. The demonstration of CO2 and CH4 detection using a fiber drawn from these materials is reported

Chalcogenide Glass Optical Waveguides for Infrared Biosensing

Due to the remarkable properties of chalcogenide (Chg) glasses, Chg optical waveguides should play a significant role in the development of optical biosensors. This paper describes the fabrication and properties of chalcogenide fibres and planar waveguides. Using optical fibre transparent in the mid-infrared spectral range we have developed a biosensor that can collect information on whole metabolism alterations, rapidly and in situ. Thanks to this sensor it is possible to collect infrared spectra by remote spectroscopy, by simple contact with the sample. In this way, we tried to determine spectral modifications due, on the one hand, to cerebral metabolism alterations caused by a transient focal ischemia in the rat brain and, in the other hand, starvation in the mouse liver. We also applied a microdialysis method, a well known technique for in vivo brain metabolism studies, as reference. In the field of integrated microsensors, reactive ion etching was used to pattern rib waveguides between 2 and 300 μm wide. This technique was used to fabricate Y optical junctions for optical interconnections on chalcogenide amorphous films, which can potentially increase the sensitivity and stability of an optical micro-sensor. The first tests were also carried out to functionalise the Chg planar waveguides with the aim of using them as (bio)sensors

MafB-restricted local monocyte proliferation precedes lung interstitial macrophage differentiation.

peer reviewedResident tissue macrophages (RTMs) are differentiated immune cells that populate distinct niches and exert important tissue-supportive functions. RTM maintenance is thought to rely either on differentiation from monocytes or on RTM self-renewal. Here, we used a mouse model of inducible lung interstitial macrophage (IM) niche depletion and refilling to investigate the development of IMs in vivo. Using time-course single-cell RNA-sequencing analyses, bone marrow chimeras and gene targeting, we found that engrafted Ly6C+ classical monocytes proliferated locally in a Csf1 receptor-dependent manner before differentiating into IMs. The transition from monocyte proliferation toward IM subset specification was controlled by the transcription factor MafB, while c-Maf specifically regulated the identity of the CD206+ IM subset. Our data provide evidence that, in the mononuclear phagocyte system, the ability to proliferate is not merely restricted to myeloid progenitor cells and mature RTMs but is also a tightly regulated capability of monocytes developing into RTMs in vivo

NMR parameters in alkali, alkaline earth and rare earth fluorides from first principle calculations

19F isotropic chemical shifts for alkali, alkaline earth and rare earth of column 3 basic fluorides are measured and the corresponding isotropic chemical shieldings are calculated using the GIPAW method. When using PBE exchange correlation functional for the treatment of the cationic localized empty orbitals of Ca2+, Sc3+ (3d) and La3+ (4f), a correction is needed to accurately calculate 19F chemical shieldings. We show that the correlation between experimental isotropic chemical shifts and calculated isotropic chemical shieldings established for the studied compounds allows to predict 19F NMR spectra of crystalline compounds with a relatively good accuracy. In addition, we experimentally determine the quadrupolar parameters of 25Mg in MgF2 and calculate the electric field gradient of 25Mg in MgF2 and 139La in LaF3 using both PAW and LAPW methods. The orientation of the EFG components in the crystallographic frame, provided by DFT calculations, is analysed in term of electron densities. It is shown that consideration of the quadrupolar charge deformation is essential for the analysis of slightly distorted environments or highly irregular polyhedra.Comment: 18 pages, 8 figures, 4 tables and ES

Systèmes différentiels à points critiques fixes. XI. Les systèmes différentiels polynomiaux stables (suite)

Bureau F.-J. Systèmes différentiels à points critiques fixes. XI. Les systèmes différentiels polynomiaux stables (suite). In: Bulletin de la Classe des sciences, tome 68, 1982. pp. 56-80

Systèmes différentiels à points critiques fixes. IX. Les systèmes différentiels polynomiaux stables (suite)

Bureau F.-J. Systèmes différentiels à points critiques fixes. IX. Les systèmes différentiels polynomiaux stables (suite) . In: Bulletin de la Classe des sciences, tome 67, 1981. pp. 755-781

Les équations différentielles du second ordre à points critiques fixes. II. Les intégrales de l'équation A4 de Painlevé

Bureau F.-J. Les équations différentielles du second ordre à points critiques fixes. II. Les intégrales de l'équation A4 de Painlevé. In: Bulletin de la Classe des sciences, tome 69, 1983. pp. 397-433

Systèmes différentiels à points critiques fixes. VII. Les systèmes différentiels polynomiaux stables

Bureau F.-J. Systèmes différentiels à points critiques fixes. VII. Les systèmes différentiels polynomiaux stables. In: Bulletin de la Classe des sciences, tome 67, 1981. pp. 512-528