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We give here the exact expression of the time dependent third order polarization predicted by the "box model" when a supercooled liquid is permanently subjected since time t = 0 to a strong electric field E(t) = E0 sin(ωt) , Dielectric Hole Burning experiment. We derive different forms of the time dependent susceptibilities, both at frequencies ω and 3ω, and examine particularly one of them. We also show that its susceptibility at ω should exhibit, at short times, presently undetected oscillations at frequency 2ω that are a signature of the "box model." We finally compare, for a large frequency range, the ω and 3ω time independent susceptibilities with the corresponding measurements on glycerol at 204.7 K. The agreement is good at frequency ω but, as already shown in Ladieu et al. [J. Chem. Phys. 134, 194507 (2011)], it is not the case at 3ω. [ABSTRACT FROM AUTHOR]

We present results of a series of experiments performed on LiBr, 6H20 from room temperature down to 172 K ≈ 1.2Tg. These ultrasound, Brillouin and depolarized light scattering, and transient grating experiments show that, above 215 K, this solution behaves like supercooled water: its zero frequency sound velocity C0 continuously decreases with decreasing temperature, and the reorientational dynamics of the water molecules can be directly detected at some temperatures of this domain. Conversely, below 215 K, a new regime sets in, where the apparent C0 is practically temperature independent and where a β, Arrenhius like, relaxation process coexists with the usual, Vogel-Fulcher like, α relaxation process of the supercooled liquid. These results are similar to those recently obtained in LiCl, 6H2O. The onset of the new regime is possibly due to an increase of the interaction of the water molecules with a neighboring Li+ ion when lowering the temperature. We also compare our results with published dielectric data on water solutions of glass forming polyalcohols. Some of them present a low temperature splitting of their relaxation time similar to what is found in LiBr, 6H2O. [ABSTRACT FROM AUTHOR]

We report the results of a series of ultrasound, Brillouin scattering, and optical heterodyne detected transient grating experiments performed on a LiCl, 6H2O solution from room temperature down to the vicinity of its liquid-glass transition, Tg∼138 K. Down to T∼215 K, the supercooled liquid has a behavior similar to what is expected for supercooled water: its zero frequency sound velocity, C0, continuously decreases while the corresponding infinite frequency velocity, C∞, sharply increases, reflecting the increasing importance of H bonding when temperature is lowered. Below 215 K, specific aspects of the solution, presumably related to the role of the Li+ and Cl- ions, modify the thermal behavior of C0, while a β relaxation process also appears and couples to the sound propagation. The origin of those two effects is briefly discussed. [ABSTRACT FROM AUTHOR]

Prigogine–Defay ratios and, more recently, their frequency extension have been proposed to be a measure of the number of nonmacroscopic processes involved in the relaxation dynamics of supercooled liquids. We show that the microscopic theory of the Navier–Stokes equations of those liquids provides a consistent thermodynamic framework in which all possible dynamical Prigogine–Defay ratios can be expressed in terms of the same relaxation functions and that these ratios provide less information than the microscopic theory itself. The latter shows that more than one relaxation process is certainly always involved in this relaxation dynamics, whatever is the molecular dynamics, or experimental, technique used to determine the latter. [ABSTRACT FROM AUTHOR]

We present here the calculation of the "time dependent" moduli of the third order, dielectric, susceptibilities measured at the frequency ω of the applied electric field and at the frequency 3ω. The calculation is performed within the frame work of the "box model," both in the ideal case of a pure third order polarization and in the practical case studied by Samanta and Richert [J. Chem. Phys. 140, 247101 (2014)] where a first order polarization contribution is also detected. We show that, in the two cases, those two modules have a largely different dynamics and that the results can be easily compared with experiments thanks to the data gathered by Samanta and Richert [J. Chem. Phys. 140, 247101 (2014)]. This should provide a new test on the validity of the "box model." [ABSTRACT FROM AUTHOR]

We present the results of a numerical study of the effects of the induced dipole–induced dipole interaction on the line shape of the internal ν1 and ν3 modes of NF3 in the plastic phase. Comparisons are made both with the experiment and with the results of a previous theoretical analysis of the effect. [ABSTRACT FROM AUTHOR]

The systematic development of the harmonic, intermolecular, internal mode interaction energy in terms of symmetry adapted Wigner functions of the molecular orientations is given for a plastic crystal. This development is used for the study of the Raman profile of a mode with a strong induced dipole-induced dipole interaction between the vibrating molecules. An approximate form of the profile is proposed, and compared with measurements made on NF3 by Gilbert and Nectoux. [ABSTRACT FROM AUTHOR]

A molecular dynamics simulation of a realistic model of neopentane [C(CH3)4] in its plastic phase has been performed on a sample of 6×6×6 fcc unit cells (i.e., 864 molecules) at 135, 175, and 230 K. The molecules of the simulated sample interact through phenomenological exp-6, atom–atom potentials between all the atoms of nearest neighbor molecules. The orientational probability density function (opdf), the displacement probability density function (dpdf), and its second moment the Debye–Waller factor have been computed. We confirm the very large value and the important thermal variation of the Debye–Waller factor and the strong anisotropy of the opdf deduced from neutron diffraction experiments. The computed opdf is very well reproduced by a mean-field calculation making use only of the microscopic intermolecular potential and of the equilibrium position of the molecular centers of mass, a result in line with the isotropic character of the dpdf, but not valid for other plastic crystals made of molecules with different geometries. [ABSTRACT FROM AUTHOR]

Tissue macrophages in many adult organs originate from yolk sac (YS) progenitors, which invade the developing embryo and persist by means of local self-renewal. However, the route and characteristics of YS macrophage trafficking during embryogenesis are incompletely understood. Here we show the early migration dynamics of YS-derived macrophage progenitors in vivo using fate mapping and intravital microscopy. From embryonic day 8.5 (E8.5) CX3CR1+ pre-macrophages are present in the mouse YS where they rapidly proliferate and gain access to the bloodstream to migrate towards the embryo. Trafficking of premacrophages and their progenitors from the YS to tissues peaks around E10.5, dramatically decreases towards E12.5 and is no longer evident from E14.5 onwards. Thus, YS progenitors use the vascular system during a restricted time window of embryogenesis to invade the growing fetus. These findings close an important gap in our understanding of the development of the innate immune system. [ABSTRACT FROM AUTHOR]

A response from the author of the article "Third order susceptibilities in supercooled liquids and the "box model" theory versus experiments" in the June 27, 2014 issue is presented.

A brief review is presented of the situation concerning the dielectric hole burning technique applied to supercooled (molecular) liquids. Some of the problems related to recently obtained results are discussed. [ABSTRACT FROM AUTHOR]

The RNA alphavirus Semliki Forest (SFV) triggers apoptosis in various mammalian cells, but it has remained controversial at what infection stage and by which signalling pathways host cells are killed. Both RNA synthesis-dependent and -independent initiation processes and mitochondrial as well as death receptor signalling pathways have been implicated. Here, we show that SFV-induced apoptosis is initiated at the level of RNA replication or thereafter. Moreover, by expressing antiapoptotic genes from recombinant SFV (replicons) and by using neutralizing reagents and gene-knockout cells, we provide clear evidence that SFV does not require CD95L-, TRAIL (tumor necrosis factor-related apoptosis-inducing ligand)- or tumor necrosis factor-mediated signalling but mitochondrial Bak to trigger cytochrome c release, the fall in the mitochondrial membrane potential, apoptotic protease-activating factor-1/caspase-9 apoptosome formation and caspase-3/-7 activation. Of seven BH3-only proteins tested, only Bid contributed to effective SFV-induced apoptosis. However, caspase-8 activation and Bid cleavage occurred downstream of Bax/Bak, indicating that truncated Bid formation serves to amplify rather than trigger SFV-induced apoptosis. Our data show that SFV sequentially activates a mitochondrial, Bak-mediated, caspase-8-dependent and Bid-mediated death signalling pathway that can be accurately dissected with gene-knockout cells and SFV replicons carrying antiapoptotic genes.Cell Death and Differentiation (2008) 15, 1396–1407; doi:10.1038/cdd.2008.61; published online 25 April 2008 [ABSTRACT FROM AUTHOR]

The constitutive equations including the energy conservation aspect, for the long-wavelength dynamics of a liquid comprised of identical, axially symmetric, rigid molecules are microscopically derived. These equations are extended to the case where the dynamics is generated by the interactions of two coherent lasers (the pumps) with the liquid. This interaction corresponds to a weak energy absorption and also to the coupling of the pumps with fluctuations in the mass density, the molecular orientation density and the temperature of the liquid. The microscopic equations generalise those phenomenologically derived in Pick et al. [1] where the role of the temperature fluctuations was ignored. Constraints on the relaxation functions related to the temperature fluctuations and to their coupling with density are derived. [ABSTRACT FROM AUTHOR]

We present an analysis, based on a phenomenological set of Generalised Navier-Stokes equations, of Heterodyne Detected Transient Gratings on supercooled molecular liquids of anisotropic molecules. This set of equations generalises equations proven in Franosch, Latz and Pick [24] for the same type of liquids. It also takes into account the three different sources generated by the laser pumping process pertinent for these experiments. We give analytical expressions for the response functions that can be measured using the different polarisation of the experimental set-up. Specialising to the case of parallel polarisation (where longitudinal phonons are launched), we show that each response function is a sum of the same seven “elementary response functions” (ERFs) whose time and temperature evolutions are individually analysed. We also show that the response functions corresponding to two of the sources can be directly connected to the Laplace Transform of a light scattering signal. The ERFs generated by the heat-absorption process, which is the third source, are of a different nature. They do not have the same time and temperature behaviours and they can provide, inter alia, unique information on the rotation-translation coupling function characteristic of these liquids. [ABSTRACT FROM AUTHOR]

: We derive expressions for the intensity of the Brillouin polarized spectrum of a molecular liquid formed of axially symmetric molecules. These expressions take into account both the molecular dielectric anisotropy and the modulation of the local polarisability by density fluctuations. They also incorporate all the retardation effects which occur in such liquids. We show that the spectrum splits into a q-independent rotational contribution and q-dependent term, which reflects the propagation of longitudinal acoustic modes. In the latter, the two light scattering mechanisms enter on an equal footing and generate three scattering channels. We study the influence of the two new channels and show that they may substantially modify the Brillouin line-shape when the relaxation time of the supercooled liquid and the period of the acoustic excitation are of the same order of magnitude. [ABSTRACT FROM AUTHOR]

: The constitutive equations for the orientational dynamics of a liquid formed of linear molecules are derived microscopically. The resulting generalised Langevin equations coincide with the phenomenological approach of Dreyfus et al. [1]. Formally exact expressions are given for the phenomenological coefficients and various constraints are shown to be consequences of this microscopic approach. [ABSTRACT FROM AUTHOR]

Light scattering experiments were performed on two inorganic glass-forming liquids: ZnCl[sub 2] and 0.8TeO[sub 2]-0.2Na[sub 2]O up to 650°C. In ZnCl[sub 2], vertical-vertical and vertical-horizontal spectra were analysed with viscoelastic theory using either a Debye or a Cole-Davidson model for the memory function. We show that the Cole-Davidson memory function yields a consistent interpretation of all the spectra. The resulting shear and longitudinal relaxation times are equal within their error bars and are about 2.5 times smaller than the α-relaxation time previously determined. The static shear viscosity values deduced from the analysis of the propagating transverse waves agree, at all temperatures, with the measured viscosity values. [ABSTRACT FROM AUTHOR]

The dynamics of the fragile glass-forming liquid m-toluidine is investigated using the time-resolved optical Kerr effect. Its relaxation processes are measured with the help of a heterodyne detection technique from 10-14 to 10-9s, in the temperature range 266-295K. The measured signal decay can be fitted by expressions derived from mode-coupling theory, with a clear identification of the different dynamic regimes. The corresponding parameters agree with values derived from light scattering experiments. [ABSTRACT FROM AUTHOR]

The article evaluates the hypothesis that industrial segment sales and profit disclosure, together with industry sales projections provide significantly accurate estimates of total-entity sales and earnings. The development of the segment-based prediction model is constrained by the industrial statistics presently published in Great Britain. An examination of the annual reports for the chosen 50 companies for the six years reveals that only 34 disclosed industrial segment revenue and profit data. There are 10 companies that did not disclose any segment information throughout the period because, in the opinion of the directors, the company did not operate substantially in more than one class of business.

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