Origin of tryptophan fluorescence lifetimes. Part 2: fluorescence lifetimes origin of tryptophan in proteins.

Fluorescence intensity decays of L-tryptophan in proteins dissolved in pH 7 buffer, in ethanol and in 6 M guanidine pH 7.8 and in lyophilized proteins were measured. In all protein conditions, three lifetimes were obtained along the emission spectrum (310-410 nm).

Proteomics applied to the authentication of fish glue: application to a 17th century artwork sample.

This work provides the first identification of fish glue from a few micrograms of a 17(th) century artwork sample using an adapted proteomics approach. Fish glue has been widely used as a binder in various art objects such as paintings, manuscripts or polychrome objects however its authentication remains particularly challenging. The lack of information on fish species in genomic and proteomic databases represents a major drawback.

Laser-induced growth of nanocrystals embedded in porous materials.

Space localization of the linear and nonlinear optical properties in a transparent medium at the submicron scale is still a challenge to yield the future generation of photonic devices. Laser irradiation techniques have always been thought to structure the matter at the nanometer scale, but combining them with doping methods made it possible to generate local growth of several types of nanocrystals in different kinds of silicate matrices. This paper summarizes the most recent works developed in our group, where the investigated nanoparticles are either made of metal (gold) or chalcogenide semiconductors (CdS, PbS), grown in precursor-impregnated porous xerogels under different laser irradiations.

Identification of cell wall proteins in the flax (Linum usitatissimum) stem.

Sequential salt (CaCl2 , LiCl) extractions were used to obtain fractions enriched in cell wall proteins (CWPs) from the stem of 60-day-old flax (Linum usitatissimum) plants. High-resolution FT-ICR MS analysis and the use of recently published genomic data allowed the identification of 11 912 peptides corresponding to a total of 1418 different proteins. Subcellular localization using TargetP, Predotar, and WoLF PSORT led to the identification of 152 putative flax CWPs that were classified into nine different functional classes previously established for Arabidopsis thaliana.

Formal Laurent series in several variables.

We explain the construction of fields of formal infinite series in several variables, generalizing the classical notion of formal Laurent series in one variable. Our discussion addresses the field operations for these series (addition, multiplication, and division), the composition, and includes an implicit function theorem.

Further insights in the ability of classical nonadditive potentials to model actinide ion-water interactions.

Pursuing our efforts on the development of accurate classical models to simulate radionuclides in complex environments (Réal et al., J. Phys.

Probing the nature of chemical bonding in uranyl(VI) complexes with quantum chemical methods.

To assess the nature of chemical bonds in uranyl(VI) complexes with Lewis base ligands, such as F(-), Cl(-), OH(-), CO(3)(2-), and O(2)(2-), we have used quantum chemical observables, such as the bond distances, the internal symmetric/asymmetric uranyl stretch frequencies, and the electron density with its topology analyzed using the quantum theory of atoms-in-molecules. This analysis confirms that complex formation induces a weakening of the uranium-axial oxygen bond, reflected by the longer U-O(yl) bond distance and reduced uranyl-stretching frequencies. The strength of the ligand-induced effect increases in the order H(2)O < Cl(-) < F(-) < OH(-) < CO(3)(2-) < O(2)(2-).

Structure-dependent interatomic dispersion coefficients in oxides with maximally localized Wannier functions.

The interatomic C(6) dispersion coefficients in crystalline and amorphous SiO(2) and ZrO(2) structures were obtained with the approach proposed by Silvestrelli (2008 Phys. Rev. Lett.

H2-induced copper and silver nanoparticle precipitation inside sol-gel silica optical fiber preforms.

Ionic copper- or silver-doped dense silica rods have been prepared by sintering sol-gel porous silica xerogels doped with ionic precursors. The precipitation of Cu or Ag nanoparticles was achieved by heat treatment under hydrogen followed by annealing under air atmosphere. The surface plasmon resonance bands of copper and silver nanoparticles have been clearly observed in the absorption spectra.

Two-dimensional ECD FT-ICR mass spectrometry of peptides and glycopeptides.

2D FT-ICR MS allows the correlation between precursor and fragment ions by modulating ion cyclotron radii for fragmentation modes with radius-dependent efficiency in the ICR cell without the need for prior ion isolation. This technique has been successfully applied to ion-molecule reactions, Collision-induced dissociation and infrared multiphoton dissociation. In this study, we used electron capture dissociation for 2D FT-ICR MS for the first time, and we recorded two-dimensional mass spectra of peptides and a mixture of glycopeptides that showed fragments that are characteristic of ECD for each of the precursor ions in the sample.

Spatial propagation of coherency matrix in polarization optics.

In this work, the question of the coherency matrix propagation of a light beam is addressed by means of the analysis of interpolation processes between two physical situations. These physical situations are defined according to the second order statistical properties of the underlying process. Two states of a light beam or the path in a medium to go from a physical situation at distance z(1) to another one at distance z(2) is related to the correlation between both these physical situations.

Highly controlled synthesis of nanometric gold particles by citrate reduction using the short mixing, heating and quenching times achievable in a microfluidic device.

Homodispersed 1.8 nm gold nanoparticles were obtained reproducibly in high yields using the classical Turkevich protocol at a high concentration in a continuous flow capillary reactor. The microfluidic reactor made from commercially available items permitted short mixing, heating and quenching times which are the key parameters of this synthesis.

Interacting ultracold bosons in disordered lattices: sensitivity of the dynamics to the initial state.

We study the dynamics of a nonlinear one-dimensional disordered system obtained by coupling the Anderson model with the Gross-Pitaevskii equation. We introduce a single quantity globally characterizing the localization of the system. This quantity obeys a scaling law with respect to the width of the initial state, which can be used to characterize the dynamics independently of the initial state.

Spatial and temporal dynamics of size-structured photosynthetic parameters (PAM) and primary production (13C) of pico- and nano-phytoplankton in an atoll lagoon.

Atoll lagoons display a high diversity of trophic states due mainly to their specific geomorphology, and probably to their level and mode of human exploitation. We investigated the functioning of the Ahe atoll lagoon, utilized for pearl oyster farming, through estimations of photosynthetic parameters (pulse amplitude modulation fluorometry) and primary production ((13)C incorporation) measurements of the size structured phytoplankton biomass (<2 μm and >2 μm). Spatial and temporal scales of variability were surveyed during four seasons, over 16 months, at four sites within the lagoon.

Strategic cell-cycle regulatory features that provide mammalian cells with tunable G1 length and reversible G1 arrest.

Transitions between consecutive phases of the eukaryotic cell cycle are driven by the catalytic activity of selected sets of cyclin-dependent kinases (Cdks). Yet, their occurrence and precise timing is tightly scheduled by a variety of means including Cdk association with inhibitory/adaptor proteins (CKIs). Here we focus on the regulation of G1-phase duration by the end of which cells of multicelled organisms must decide whether to enter S phase or halt, and eventually then, differentiate, senesce or die to obey the homeostatic rules of their host.

Experimental test of universality of the Anderson transition.

We experimentally test the universality of the Anderson three dimensional metal-insulator transition, using a quasiperiodic atomic kicked rotor. Nine sets of parameters controlling the microscopic details have been tested. Our observation indicates that the transition is of second order, with a critical exponent independent of the microscopic details; the average value 1.

A human Polycomb isoform lacking the Pc box does not participate to PRC1 complexes but forms protein assemblies and represses transcription.

Polycomb repression controls the expression of hundreds of genes involved in development and is mediated by essentially two classes of chromatin-associated protein complexes. The Polycomb repressive complex 2 (PRC2) trimethylates histone H3 at lysine 27, an epigenetic mark that serves as a docking site for the PRC1 protein complex. Drosophila core PRC1 is composed of four subunits: Polycomb (Pc), Posterior sex combs (Psc), Polyhomeotic (Ph) and Sex combs extra (Sce).

A dynamical model of oocyte maturation unveils precisely orchestrated meiotic decisions.

Maturation of vertebrate oocytes into haploid gametes relies on two consecutive meioses without intervening DNA replication. The temporal sequence of cellular transitions driving eggs from G2 arrest to meiosis I (MI) and then to meiosis II (MII) is controlled by the interplay between cyclin-dependent and mitogen-activated protein kinases. In this paper, we propose a dynamical model of the molecular network that orchestrates maturation of Xenopus laevis oocytes.

Emission factors of gaseous pollutants from recent kerosene space heaters and fuels available in France in 2010.

Unlabelled: Laboratory measurements of the gaseous emission factors (EF) from two recent kerosene space heaters (wick and injector) with five different fuels have been conducted in an 8-m(3) environmental chamber. The two heaters tested were found to emit mainly CO(2), CO, NO, NO(2), and some volatile organic compounds (VOCs). NO(2) is continuously emitted during use, with an EF of 100-450 μg per g of consumed fuel.

Multicore fiber for cold-atomic cloud monitoring.

Thanks to an all solid core photonic crystal fiber (PCF) used as a multicore fiber, we propose and experimentally demonstrate what is to our knowledge a new optical detection scheme for the spontaneous emission collection of cold atoms. A Magneto-Optical Trap (MOT) is placed in front of a polished PCF end-face. As they display a higher optical index than the surrounding cladding silica, the 108 rods (equivalent to a 108 pixels camera) of this PCF are light guiding and behave like an array of detectors.

Convection-induced stabilization of optical dissipative solitons.

In spatially extended convective systems, the reflection symmetry breaking induced by drift effects leads to a striking nonlinear effect that drastically affects the formation and stability of dissipative solitons in optical parametric oscillators. The phenomenon of nonlinear-induced convection dynamics is revealed using a model of the complex quintic Ginzburg-Landau equation with nonlinear gradient terms in it. Mechanisms leading to stabilization of dissipative solitons by convection are singled out.

Pyrene measurements in sooting low pressure methane flames by jet-cooled laser-induced fluorescence.

This paper presents in detail the study we carried out concerning the pyrene measurement by jet-cooled laser-induced fluorescence (JCLIF) in different sooting low pressure methane flames. The aim of this paper is both to demonstrate the potentialities of this technique for the measurement of such moderately sized polycyclic aromatic hydrocarbons under sooting flame conditions and to provide new experimental data for the understanding and the development of chemical models of the soot formation processes. Several concentration profiles of pyrene measured in different sooting flame (various pressure and equivalence ratio) are presented.

Identification of animal glue species in artworks using proteomics: application to a 18th century gilt sample.

This study proposes a proteomic-based strategy for the identification of the origin species of glues used as binding media and adhesives in artworks. The methodology, based on FTICR high resolution mass spectrometry, was evaluated on glues from different animal origin (i.e.

Characterization of the Src/Abl hybrid kinase SmTK6 of Schistosoma mansoni.

Cellular protein-tyrosine kinases play key roles in signal transduction processes in eukaryotes. SmTK4 was the first Syk kinase identified in a parasite and found to be tissue-specifically transcribed in the gonads of adult Schistosoma mansoni. Functional analyses confirmed its role in oogenesis and spermatogenesis.

Direct-writing of PbS nanoparticles inside transparent porous silica monoliths using pulsed femtosecond laser irradiation.

Pulsed femtosecond laser irradiation at low repetition rate, without any annealing, has been used to localize the growth of PbS nanoparticles, for the first time, inside a transparent porous silica matrix prepared by a sol-gel route. Before the irradiation, the porous silica host has been soaked within a solution containing PbS precursors. The effect of the incident laser power on the particle size was studied.