Regulation of nestin expression by thrombin and cell density in cultures of bone mesenchymal stem cells and radial glial cells

Background  

Bone marrow stromal cells and radial glia are two stem cell types with neural phenotypic plasticity. Bone marrow mesenchymal stem cells can differentiate into osteocytes, chondrocytes and adipocytes, but can also differentiate into non-mesenchymal cell, i.e. neural cells in appropriate in vivo and in vitro experimental conditions. Likewise, radial glial cells are the progenitors of many neurons in the developing cortex, but can also generate astrocytes. Both cell types express nestin, an intermediate filament protein which is the hallmark of neural precursors.     

The morphology of submicronsized core-shell latex particles: an electron microscopy study

The core-shell structure of a range of acrylic-acrylic latexes has been investigated by combining different specimen preparation methods with transmission electron microscopy (TEM), dark-field scanning transmission electron microscopy (DSTEM) and low-voltage scanning electron microscopy (LV-SEM), including the first reported use of LV-SEM to observe composite latex particles at ambient and subambient temperatures. Spin-coating of liquid latex dispersions directly onto TEM grids or SEM stubs is shown to be a relatively straightforward mean of avoiding film formation during specimen preparation. In conjunction with double staining techniques, it has been found to be particularly convenient for characterizing the fine structure of particles with diameters down to below 100 nm.     

CORSICA: correction of structured noise in fMRI by automatic identification of ICA components

When applied to functional magnetic resonance imaging (fMRI) data, spatial independent component analysis (sICA), a data-driven technique that addresses the blind source separation problem, seems able to extract components specifically related to physiological noise and brain movements. These components should be removed from the data to achieve structured noise reduction and improve any subsequent detection and analysis of signal fluctuations related to neural activity. We propose a new automatic method called CORSICA (CORrection of Structured noise using spatial Independent Component Analysis) to identify the components related to physiological noise, using prior information on the spatial localization of the main physiological fluctuations in fMRI data. As opposed to existing spectral priors, which may be subject to aliasing effects for long-TR data sets (typically acquired with TR >1 s), such spatial priors can be applied to fMRI data, regardless of the TR of the acquisitions. By comparing the proposed automatic selection to a manual selection performed visually by a human operator, we first show that CORSICA is able to identify the noise-related components for long-TR data with a high sensitivity and a specificity of 1. On short-TR data sets, we validate that the proposed method of noise reduction allows a substantial improvement of the signal-to-noise ratio evaluated at the cardiac and respiratory frequencies, even in the gray matter, while preserving the main fluctuations related to neural activity.     

Pressure-induced phase transition(s) in KMnF3 and the importance of the excess volume for phase transitions in perovskite structures

We report a pressure-dependent investigation of KMnF(3) by x-ray diffraction up to 30 GPa. The results are discussed in the framework of Landau theory and in relation to the isostructural phase transition in SrTiO(3). The phase transition temperature near 186 K in KMnF(3) shifts to room temperature at a critical pressure of P(c) = 3.4 GPa; the pressure dependence of the transition point follows ΔP(c)/ΔT(c) = 0.0315 GPa K(-1). The transition becomes second order under high pressure, close to the tricritical point. The phase transition is determined by the rotation of MnF(6) octahedra with their simultaneous expansion along the rotation axis. The rotation angle was found to increase to 10.5° at 24 GPa. An additional anomaly was observed at higher pressure around 25 GPa, suggesting a further phase transition.     

A Consistent BGK-Type Model for Gas Mixtures

We introduce a relaxation collision operator for a mixture of gases which satisfies several fundamental properties. Different BGK type collision operators for gas mixtures have been introduced earlier but none of them could satisfy all the basic physical properties: positivity, correct exchange coefficients, entropy inequality, indifferentiability principle. We show that all those properties are verified for our model, and we derive its Navier–Stokes limit by a Chapman–Enskog expansion.     

A short walk through quantum optomechanics

This paper gives a brief review of the basic physics of quantum optomechanics and provides an overview of some of its recent developments and current areas of focus. It first outlines the basic theory of cavity optomechanical cooling and gives a brief status report of the experimental state‐of‐the‐art. It then turns to the deep quantum regime of operation of optomechanical oscillators and covers selected aspects of quantum state preparation, control and characterization, including mechanical squeezing and pulsed optomechanics. This is followed by a discussion of the “bottom‐up” approach that exploits ultracold atomic samples instead of nanoscale systems. It concludes with an outlook that concentrates largely on the functionalization of quantum optomechanical systems and their promise in metrology applications.     

Etude de la restauration de l'aluminium irradié aux electrons (Etape III)

The nature of the electron bombarded aluminium electrical recovery process has been studied by combining quenches with irradiations. Measured Frenkel pair formation rates per incident electrons as well as annealing kinetics emphasize the role of impurity interstitial trapping.     

Electrical behaviour of laser-damaged silicon photodiodes

A measurement of the electrical parameters degradation of Si photodiodes irradiated by laser visible light has been performed. The laser is a Q-switched Nd:YAG, frequency doubled, operated in single pulse mode of 4 ns duration. The applied fluence levels range up to 90 J/cm². Two kinds of irradiation process were applied: either a part of the detector active area was irradiated in single pulse mode, or a scanning of the whole detector active area was performed with successive identical pulses. It has been shown that the fluence necessary to induce significant changes (local decrease of 35%) in responsivity is several times the surface melting threshold fluence (0.5 J/cm²). Conversely, the dark current is the most sensitive parameter, increasing by about four times for high irradiation. The in-depth dopant distribution is altered by high fluence irradiation in a way that cannot be explained by simple thermal modelling.     

Jack Polynomials in Superspace

This work initiates the study of orthogonal symmetric polynomials in superspace. Here we present two approaches leading to a family of orthogonal polynomials in superspace that generalize the Jack polynomials. The first approach relies on previous work by the authors in which eigenfunctions of the supersymmetric extension of the trigonometric Calogero-Moser-Sutherland Hamiltonian were constructed. Orthogonal eigenfunctions are now obtained by diagonalizing the first nontrivial element of a bosonic tower of commuting conserved charges not containing this Hamiltonian. Quite remarkably, the expansion coefficients of these orthogonal eigenfunctions in the supermonomial basis are stable with respect to the number of variables. The second and more direct approach amounts to symmetrize products of non-symmetric Jack polynomials with monomials in the fermionic variables. This time, the orthogonality is inherited from the orthogonality of the non-symmetric Jack polynomials, and the value of the norm is given explicitly.