Influence of the structure of the mesogenic core on the thermotropic properties of ω-unsaturated fluorinated liquid crystals

Three series of calamitic liquid crystals have been prepared, consisting of a mesogenic core attached to which is a perfluorinated chain via a thioester linkage, and a hydrocarbon chain containing a terminal double bond. The rigid core is either a monophenyl, biphenyl or phenyl benzoate group. The mesomorphic properties were characterized by polarizing optical microscopy and differential scanning calorimetry. The influence of the structure of the mesogenic core and of the hydrocarbon chain length on mesomorphic behaviour was studied. Increasing the length of the alkyl chain strongly reduces the mesomorphic behaviour while increasing the number of aromatic rings in the core increases the transition temperatures, with the widest LC range observed for derivatives with the phenyl benzoate core. The introduction of a single ring as the mesogenic core is considered of great interest in the development of low cost liquid crystal materials.     

Contra-directional and other power flows in periodic iris-loaded circular waveguide (H-waves)

Physics of H-eigenwaves in a periodic iris-loaded circular waveguide is generally characterized using a number of the typical power flows. Both the reflectionless flows and the ones contra-directional over the guide's cross-section are included, as well as the curlsome ones and others.     

Preparative route to 2‐ethoxycarbonylimidazole‐4‐phosphonate and diethylimidazole‐2,4‐dicarboxylate

Practical synthesis of 2‐ethoxycarbonylimidazole‐4‐phosphonate ( 1a ) and diethyl imidazole‐2,4‐dicar‐boxylate ( 1b ) are described.     

Stabilisation d'un système de la thermoélasticité anisotrope avec feedbacks non linéaires

In this Note we study the stabilization of an anisotropic thermoelasticity system with (natural) Neumann boundary condition and nonlinear internal and/or boundary feedbacks. Our method consists of showing the exponential stability of the linear system by using an integral inequality, obtained by the technique of Bey et al. [E.J.D.E. 78 (2001) 1–23]; the stabilisation of the nonlinear system is deduced owing to the results from Nicaise [Rendiconti Di Matematica, Ser. VII 23 (2003) 83–116]. To cite this article: A. Heminna et al., C. R. Acad. Sci. Paris, Ser. I 339 (2004).     

Some Improvements in the Method of the Weakly Conjugate Operator

We present some improvements in the method of the weakly conjugate operator, one variant of the Mourre theory. When applied to certain two-body Schrödinger operators, this leads to a limiting absorption principle that is uniform on the positive real axis.     

Small and Large Scale Behavior of the Poissonized Telecom Process

The stable Telecom process has infinite variance and appears as a limit of renormalized renewal reward processes. We study its Poissonized version where the infinite variance stable measure is replaced by a Poisson point measure. We show that this Poissonized version converges to the stable Telecom process at small scales and to the Gaussian fractional Brownian motion at large scales. This process is therefore locally as well as asymptotically self-similar. The value of the self-similarity parameter at large scales, namely the self-similarity parameter of the limit fractional Brownian motion, depends on the form the Poissonized Telecom process. The Poissonized Telecom process is a Poissonized mixed moving average. We investigate more general Poissonized mixed moving averages as well.     

The heat equation under conditions on the moments in higher dimensions

We consider the heat equation on the N‐dimensional cube (0, 1)^N and impose different classes of integral conditions, instead of usual boundary ones. Well‐posedness results for the heat equation under the condition that the moments of order 0 and 1 are conserved had been known so far only in the case of , for which such conditions can be easily interpreted as conservation of mass and barycenter. In this paper we show that in the case of general N the heat equation with such integral conditions is still well‐posed, upon suitably relaxing the notion of solution. Existence of solutions with general initial data in a suitable space of distributions over (0, 1)^N are proved by introducing two appropriate realizations of the Laplacian and checking by form methods that they generate analytic semigroups. The solution thus obtained turns out to solve the heat equation only in a certain distributional sense. However, one of these realizations is tightly related to a well‐known object of operator theory, the Krein–von Neumann extension of the Laplacian. This connection also establishes well‐posedness in a classical sense, as long as the initial data are L²‐functions.     

In-spray supercharging of intact proteins by capillary electrophoresis–electrospray ionization–mass spectrometry using sheath liquid interface

Capillary electrophoresis (CE) coupled with electrospray ionization (ESI) mass spectrometry (MS) is a suitable technique for the analysis of intact proteins. The main configuration to realize this coupling is the sheath liquid interface, which is characterized by the addition of a make-up liquid providing the electric contact as well as the appropriate flow and solvent composition for optimal ionization and evaporation. One main advantage of this interface is that the composition of the sheath liquid can be tuned to modify the ionization without affecting CE selectivity and efficiency. In the case of protein ionization, this feature is particularly interesting to modulate their charge-state distribution (CSD), while keeping the separation performance unchanged.     

Online Microreactor Titanium Dioxide RPLC-LTQ-Orbitrap MS Automated Platform for Shotgun Analysis of (Phospho) Proteins in Human Amniotic Fluid

Biomarkers in amniotic fluid (AF) include both non-modified and phosphorylated proteins and can be used in the diagnosis of pregnancy-associated pathologic conditions. In this work, an integrated LC–MS method for selective, sensitive and reproducible analysis of phosphorylation in proteins has been applied to AF. Online digestion of (phospho) proteins was coupled with the selective enrichment on a TiO₂ trap, and separated by RPLC–MSⁿ of both normal and phosphorylated produced peptides. First, an AF-pooled sample was analyzed and a general map of contained proteins and biomarkers was derived in a single run. Then, individual AF samples were analyzed with a downscaled platform with improved sensitivity. On purpose, a trypsin-based CIM^® minidisk was used for online digestion of AF. The obtained protein profile was highly consistent with the one obtained with traditional off-line digestions. Moreover, the use of a specific phospho-enrichment tool followed by LTQ-Orbitrap, enhanced the confidence in the determination of protein phosphorylation state and phosphorylation sites. The phosphorylation sites of IGFBP-1 and osteopontin present in the AF of two individual samples were monitored with a total of 24 and 17 phosphopeptides, respectively, encoding for 12 putative novel phosphorylation sites in addition to known sites.     

Acronycine Analog: New Selective Synthesis of 6‐Methoxy‐3,3‐dimethyl‐3H,7H‐pyrano[2,3‐c]xanthen‐7‐one

A new, convenient, and selective route to the dimethylpyrano[2,3‐c]xanthen‐7‐one, analog of acronycine, via aromatization and dehydrogenation reactions from the corresponding saturated hexahydro intermediate is described.