Philippe Moreau

Electronic structures and charge transfer in lithium and mercury intercalated titanium disulfides

Mercury can be intercalated into TiS2 by a reaction between elemental mercury and TiS2 at room temperature. The structure of the obtained compound Hg1.24TiS2 can be described as two non-commensurate monoclinic sublattices. The mercury atoms form metal chains inserted into trigonal prismatic channels created by the expanded TiS2 host lattice. The structural arrangement and interatomic distances for this compound indicate the presence of primarily neutral mercury, with very low charge transfer, and relatively weak Hgue5f8S interactions. In order to understand this peculiar behaviour, electron band structure calculations have been made using the extended Huckel method and compared with experimental data from different spectroscopies: XAFS, EELS and XPS. Pristine TiS2 and its lithium and mercury intercalated compounds have been investigated. The experimental data are in good agreement with the calculated electronic structures. The main conclusion is that 0.24 electrons are transferred by lithium atom to the TiS2 host structure for the composition Li1TiS2. This transfer is almost equivalent on titanium (0.09 electrons) and sulphur (0.075 electrons per atom). For the mercury intercalated TiS2 phase, both calculations and experimental data show an electronic transfer from mercury to TiS2 very close to zero.

Numerical optimization of a new robotized glass blowing process

To answer an increasing need for glass product manufacturing in both small and medium series, the first glass-blower robot was recently developed. In the face of this new technology, which particularly interests crystal glass-makers, expertise remains the main decision-making element which intervenes in the choices of the design and implementation of these new processes. Finite element models of this new blowing process were developed. After the analysis of the process and of these stages, an initial sensibility study allowed us to find the essential parameters for the success of the operation. With the results of these sensitivity analyses, an optimizer was developed to adjust virtually the forming process of a linear cylindrical vase by determining the optimal forming parameters. A second optimization allowed us to determine the initial shape of the parison, an essential parameter in the successful forming of a convex cylindrical vase. Finally, the numerical tools were validated during trial campaigns carried out in crystal glass-makers.

How I treat myeloma with new agents

At present, multiple classes of agents with distinct mechanisms of action are available for the treatment of patients with multiple myeloma (MM), including alkylators, steroids, immunomodulatory agents (IMiDs), proteasome inhibitors (PIs), histone deacetylase inhibitors (DACIs), and monoclonal antibodies (mAbs). Over the last 5 years, several new agents, such as the third-generation IMiD pomalidomide, the second-generation PIs carfilzomib and ixazomib, the DACI panobinostat, and 2 mAbs, elotuzumab and daratumumab, have been approved, incorporated into clinical guidelines, and have transformed our approach to the treatment of patients. These agents may be part of doublet or triplet combinations, or incorporated into intensive strategies with autologous stem cell transplantation. In this review, I discuss the different treatment options available today for the treatment of MM in frontline and relapse settings.

Mercury sublattice melting transition in the misfit intercalation compound H1.24TiS2

Abstract Mercury can be intercalated into TiS 2 to form a compound, Hg 1.24 TiS 2 , which exhibits novel behavior, including superstoichiometric mercury uptake, no, or at most a very small degree of, guest-host charge transfer, and the formation of incommensurate Hg chains in the guest galleries. Herein, X-ray powder diffraction (XPD) and differential scanning calorimetry (DSC) have been used to determine the effects of temperature on the Hg 1.24 TiS 2 structure from ambient temperature to 500 K. DSC studies reveal the presence of a reversible thermal transition near 473 K. The XPD patterns taken below the transition temperature are all characteristic of the ambient temperature structure together with modest sublattice thermal expansion with increasing temperature. However, above the transition temperature, all of the reflections uniquely associated with the Hg sublattice disappear, while the positions and intensities of the (001) reflections confirm the Hg remains intercalated. Thus, above the 473 K transition the in-plane Hg-sublattice structure and the associated intercalant Hg chains have melted to form guest layers with liquid-like disorder. The evolution of the host and Hg sublattice cell parameters as a function of temperature exhibits the expected discontinuous behavior associated with such a first-order transition.

Genomic organization and nucleotide sequence of a long mosaic repetitive DNA in the mouse genome

A long mosaic repetitive sequence (LMRS) was isolated from a mouse liver genome library using a mouse repetitive DNA as a probe. LMRS exhibits the following features: (1) it is almost 15 kb in length; (2) it is partly organized in tandem array and frequently interrupted by other repeated sequences; and (3) it is located predominantly on the A3 band of the mouse X Chromosome (Chr). One fragment of LMRS (B6) shows restriction fragment length polymorphism (RFLP) between different mouse strains, and is thus potentially useful for mapping studies. The nucleotide sequence confirms a mosaic organization of LMRS which includes three repeats in the 5′ part, showing similarity with the 5′ end of L1Md-A2, and seven long A+T rich segments in the central part of the element. Our findings suggest that this sequence may have arisen from the duplication of an ancestral motif and has expanded by successive waves of amplification and invasion by foreign sequences.

Magneto-active substrates for local mechanical stimulation of living cells

Cells are able to sense and react to their physical environment by translating a mechanical cue into an intracellular biochemical signal that triggers biological and mechanical responses. This process, called mechanotransduction, controls essential cellular functions such as proliferation and migration. The cellular response to an external mechanical stimulation has been investigated with various static and dynamic systems, so far limited to global deformations or to local stimulation through discrete substrates. To apply local and dynamic mechanical constraints at the single cell scale through a continuous surface, we have developed and modelled magneto-active substrates made of magnetic micro-pillars embedded in an elastomer. Constrained and unconstrained substrates are analysed to map surface stress resulting from the magnetic actuation of the micro-pillars and the adherent cells. These substrates have a rigidity in the range of cell matrices, and the magnetic micro-pillars generate local forces in the range of cellular forces, both in traction and compression. As an application, we followed the protrusive activity of cells subjected to dynamic stimulations. Our magneto-active substrates thus represent a new tool to study mechanotransduction in single cells, and complement existing techniques by exerting a local and dynamic stimulation, traction and compression, through a continuous soft substrate.

Mercury Intercalation into Lamellar Transition Metal Disulfides

Abstract Mercury can be intercalated at room or moderate temperature into lamellar titanium and tantalum disulfides. The structure of intercalated compounds is described by two incommensurate sublattices corresponding to the disulfide host layers and the intercalated mercury, respectively. Depending on the synthetic procedure two different phases are obtained for mercury intercalated tantalum disulfide, which mainly differ in the relative orientation of disulfide and mercury networks. Mercury intercalation of 1T-TaS2 results in a tantalum coordination change from octahedral to trigonal prismatic. The mercury-to-host charge transfer is very low and more heavily involves the sulfur orbitals than previously observed for lithium intercalated compounds.

A novel multisite confocal system for rapid Ca2+ imaging from submicron structures in brain slices

In brain slices, resolving fast Ca2+ fluorescence signals from submicron structures is typically achieved using 2-photon or confocal scanning microscopy, an approach that limits the number of scanned points. The novel multiplexing confocal system presented here overcomes this limitation. This system is based on a fast spinning disk, a multimode diode laser and a novel high-resolution CMOS camera. The spinning disk, running at 20 000 rpm, has custom-designed spiral pattern that maximises light collection, while rejecting out-of-focus fluorescence to resolve signals from small neuronal compartments. Using a 60× objective, the camera permits acquisitions of tens of thousands of pixels at resolutions of ~250 nm per pixel in the kHz range with 14 bits of digital depth. The system can resolve physiological Ca2+ transients from submicron structures at 20 to 40 μm below the slice surface, using the low-affinity Ca2+ indicator Oregon Green BAPTA-5N. In particular, signals at 0.25 to 1.25 kHz were resolved in single trials, or through averages of a few recordings, from dendritic spines and small parent dendrites in cerebellar Purkinje neurons. Thanks to an unprecedented combination of temporal and spatial resolution with relatively simple implementation, it is expected that this system will be widely adopted for multisite monitoring of Ca2+ signals.

Modelling thermal contact resistance on glass forming processes with special interface finite elements

The forming process of glass containers is a complex coupled thermal/mechanical problem with interaction between the heat transfer analysis and the viscous flow of molten glass. The transfer of heat and change of viscosity are fundamental phenomena in this process. The changes in temperature influence the very process of heat transfer since the thermal properties of glass change with temperature. On the other hand the great dependence of glass viscosity with the temperature influences dramatically the flow of the material and therefore the final product. The successive changes in shape produced by gravity and blow pressure, which depend on the actual properties that are influenced by temperature, affect subsequently the heat transfer process.

Mercury Intercalation in Titanium and Tantalum Disulfides

Mercury intercalation in TiS2 and TaS2 can be carried out using “soft chemistry”, techniques, i.e at room or low (T<200°C) temperatures.