A Manufacturing Technique for Binary Clathrate Hydrates for Cold and Very Cold Neutron Production.

Intense sources of very cold neutrons (VCNs) would be beneficial for various neutron scattering techniques and low-energy particle physics experiments. Binary clathrate hydrates hosting deuterated tetrahydrofuran (THF-d) and dioxygen show promise as potential moderators for such sources due to a rich spectrum of localized low-energy excitations of the encaged guest molecules. In this article, we present a reliable manufacturing technique for such hydrates.

Stridor in multiple system atrophy: Consensus statement on diagnosis, prognosis, and treatment.

Multiple system atrophy (MSA) is a neurodegenerative disorder characterized by a combination of autonomic failure, cerebellar ataxia, and parkinsonism. Laryngeal stridor is an additional feature for MSA diagnosis, showing a high diagnostic positive predictive value, and its early occurrence might contribute to shorten survival. A consensus definition of stridor in MSA is lacking, and disagreement persists about its diagnosis, prognosis, and treatment.

Combined spatial and retrospective analysis of fluoroalkyl chemicals in fluvial sediments reveal changes in levels and patterns over the last 40 years.

Bed sediments and a dated sediment core were collected upstream and downstream from the city of Lyon (France) to assess the spatial and temporal trends of contamination by per- and polyfluoroalkyl substances (PFASs) in this section of the Rhône River. Upstream from Lyon, concentrations of total PFASs (ΣPFASs) in sediments are low (between 0.19 and 2.

Role of the floodplain lakes in the methylmercury distribution and exchanges with the Amazon River, Brazil.

Seasonal variability of dissolved and particulate methylmercury (F-MeHg, P-MeHg) concentrations was studied in the waters of the Amazon River and its associated Curuai floodplain during hydrological year 2005-2006, to understand the MeHg exchanges between these aquatic systems. In the oxic white water lakes, with neutral pH, high F-MeHg and P-MeHg concentrations were measured during the rising water stage (0.70±0.

Exposure to low environmental concentrations of manganese, lead, and cadmium alters the serotonin system of blue mussels.

Serotonin plays a crucial role in mussel survival and reproduction. Although the serotonin system can be affected by metals, the effects of environmental concentrations of metals such as manganese (Mn), lead (Pd), and cadmium (Cd) have never been studied in blue mussels. The present study aimed to determine the effects of exposure to Mn, Pb, or Cd on serotonin levels, monoamine oxidase (MAO) activity, and serotonin transporter (SERT) levels in the blue mussel Mytilus edulis.

Dosimetric Characteristics of an EMF Delivery System Based on a Real-Time Impedance Measurement Device.

In this paper, the dosimetric characterization of an EMF exposure setup compatible with real-time impedance measurements of adherent biological cells is proposed. The EMF are directly delivered to the 16-well format plate used by the commercial xCELLigence apparatus. Experiments and numerical simulations were carried out for the dosimetric analysis.

Imaging critical fluctuations of pure fluids and binary mixtures.

We use optical microscopy techniques to directly visualize the structures that emerge in binary mixtures and pure fluids near their respective critical points. We attempt to understand these structures by studying the image formation using both a phase contrast and a dark field filter to our microscope. We found that images of critical fluctuations for both liquid-liquid and liquid-gas critical systems have gray level intensity histograms with Gaussian shape.

Membrane nanowaves in single and collective cell migration.

We report the characterization of three-dimensional membrane waves for migrating single and collective cells and describe their propagation using wide-field optical profiling technique with nanometer resolution. We reveal the existence of small and large membrane waves the amplitudes of which are in the range of ∼ 3-7 nm to ∼ 16-25 nm respectively, through the cell. For migrating single-cells, the amplitude of these waves is about 30 nm near the cell edge.

The fragmented character of Middle Palaeolithic stone tool technology.

The importance of the transport of stone artefacts in structuring Neandertal lithic assemblages has often been addressed, but the degree to which this led to fragmentation of lithic reduction over Middle Palaeolithic landscapes has not been explicitly studied thus far. Large-scale excavations of Middle Palaeolithic open-air sites and refitting studies of the retrieved assemblages have yielded new, high-resolution data on the mobile aspects of Neandertal stone tool technology. In this paper, we integrate lithic technology and raw material data from recent studies of Middle Palaeolithic open-air and rock shelter sites in Western Europe.

Cooperative and reciprocal chiral structure formation of an alanine-based peptide confined at the surface of cationic surfactant membranes.

The confinement of anionic oligoalanine peptides at the surface of cationic membranes can cooperatively reinforce peptide/peptide interactions and induce secondary-structure formation, and, reciprocally, induce chirality expression of the membrane at the mesoscopic level, thus leading to the formation of three-dimensional chiral fibrillar networks. Such a strong binding effect of peptides with cationic membranes and the resulting cooperative assembly behaviors are observed with two different types of cationic surfactant, namely, two-head two-tail gemini and one-head two-tail surfactants. The ensemble of assembly properties, such as critical micellar concentration (cmc), Krafft temperature (T(k) ), molecular area at the air/water interface, molecular organization (as studied by FTIR attenuated total reflectance (ATR) measurements and small-angle X-ray scattering), and morphology of the aggregates (as observed by optical and electron microscopy studies), are reported.

Tugging graphs faster: efficiently modifying path-preserving hierarchies for browsing paths.

Many graph visualization systems use graph hierarchies to organize a large input graph into logical components. These approaches detect features globally in the data and place these features inside levels of a hierarchy. However, this feature detection is a global process and does not consider nodes of the graph near a feature of interest.

Immobilization of selenite on Fe3O4 and Fe/Fe3C ultrasmall particles.

The sorption of selenite ions onto Fe3O4 and Fe/Fe3C nanoparticles (NPs) was studied in aqueous solutions under anoxic conditions using gamma spectrometry and X-ray absorption spectrometry (XAS) techniques. This is the first study related to the remedial applications of Fe/Fe3C NPs. FesO4 NPs have been prepared by conventional coprecipitation of Fe(II) and Fe(III) in basic solutions.

Planar waveguides formed by Ag+-Na+ ion exchange in nonlinear optical glasses: diffusion and optical properties.

All-optical communication systems are the subject of intense research related to the integration of nonlinear optical materials. In sodiocalcic borophosphate glasses that contain niobium oxide and exhibit high nonlinear optical indices, planar waveguides have been formed by a Ag(+)-Na(+) ion-exchange technique. WKB analysis has been used to characterize the diffusion profiles of silver ions exchanged in glass substrate samples chemically by an electron microprobe technique and optically by an M-line technique.

"Click" dendrimers: synthesis, redox sensing of Pd(OAc)2, and remarkable catalytic hydrogenation activity of precise Pd nanoparticles stabilized by 1,2,3-triazole-containing dendrimers.

"Click" dendrimers containing 1,2,3-triazolyl ligands that coordinate to PdII(OAc)2 have been synthesized in view of catalytic applications. Five of these dendrimers contain ferrocenyl termini directly attached to the triazole ligand in order to monitor the number of PdII that are introduced into the dendrimers by cyclic voltammetry. Reduction of the PdII-triazole dendrimers by using NaBH4 or methanol yields Pd nanoparticles (PdNPs) that are stabilized either by several dendrimers (G0, DSN) or by encapsulation inside a dendrimer (G1 and G2: DEN), as confirmed by TEM.

[Tumor angiogenesis].

Following the work of Folkman, it appears that angiogenesis, which consists in the formation of new blood vessels able to deliver oxygen and nutriments to tumor cells, is a major step in the evolution of tumors, which can only grow after the onset of the angiogenic switch. Numerous factors play a role in angiogenesis stimulation or inhibition : the vascular endothelial growth factor and fibroblastic growth factors as well as angiopoietin are proangiogenic, whereas angiostatin and platelet factor 4 are anti-angiogenic. The discovery of these molecules and of the molecular mechanisms of their activity allowed the identification of new therapeutic targets, which appear relevant for the treatment of cancer.

Field-temperature phase diagrams in chiral tilted smectics, evidencing ferroelectric and ferrielectric phases.

Usual ferroelectric compounds undergo a paraelectric-to-ferroelectric phase transition when the susceptibility of the electric polarization density changes its sign. The temperature is the only thermodynamic field that governs the phase transition. Chiral tilted smectics may also present an improper ferroelectricity when there is a tilt angle between the average long axis direction and the layer normal.

Vibrational absorption and circular dichroism studies of trans-(3S,4S)-d6-cyclopentene in the gas phase.

Vibrational absorption (IR) and circular dichroism (VCD) measurements of trans-(3S,4S)-d6-cyclopentene in the gas phase were performed in the C-H, C-D, and mid-infrared regions. In this study, we report the first VCD spectra recorded at high spectral resolution (up to 0.5 cm(-1)) with a very good signal-to-noise ratio (differential absorbance lower than 5 x 10(-6)).

Dissociated roles for the lateral and medial septum in elemental and contextual fear conditioning.

Extensive evidence indicates that the septum plays a predominant role in fear learning, yet the direction of this control is still a matter of debate. Increasing data suggest that the medial (MS) and lateral septum (LS) would be differentially required in fear conditioning depending on whether a discrete conditional stimulus (CS) predicts, or not, the occurrence of an aversive unconditional stimulus (US). Here, using a tone CS-US pairing (predictive discrete CS, context in background) or unpairing (context in foreground) conditioning procedure, we show, in mice, that pretraining inactivation of the LS totally disrupted tone fear conditioning, which, otherwise, was spared by inactivation of the MS.

Characterization of a heat flux sensor using short pulse laser calibration.

A method to calibrate classical heat flux sensors is presented. The classical approach to measure the temperature inside a known material by using a thermocouple fails when the measurement time is very short. In this work the surface heat flux is determined by solving the inverse heat conduction problem using a noninteger identified system as a direct model for the estimation process.

Defects in divided zinc-copper aluminate spinels: structural features and optical absorption properties.

Zn1-xCuxAl2O4 (0 < or = x < 0.30) compounds have been synthesized by polyesterification using metallic salts and annealing at low temperatures as well as by conventional solid state. XRD-powder data refinements (Rietveld method) have demonstrated that both compound series crystallize in the spinel structure (Fd3m) and exhibit similar inversion rates.

Mechanistic aspects of the solid-state transformation of ammonium cyanate to urea at high pressure.

The chemical transformation of ammonium cyanate into urea has been of interest to many generations of scientists since its discovery by Friedrich Wöhler in 1828. Although widely studied both experimentally and theoretically, several mechanistic aspects of this reaction remain to be understood. In this paper, we apply computational methods to investigate the behavior of ammonium cyanate in the solid state under high pressure, employing a theoretical approach based on the self-consistent-charges density-functional tight-binding method (SCC-DFTB).

Steric and electronic effects relating to the Cu2+ Jahn-Teller distortion in Zn(1-)xCuxAl2O4 spinels.

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Fmr1 KO mice as a possible model of autistic features.

Autism is a pervasive developmental disorder appearing before the age of 3, where communication and social interactions are impaired. It also entails stereotypic behavior or restricted interests. Although this disorder was first described in 1943, little is still known about its etiology and that of related developmental disorders.

Extinction of auditory fear conditioning requires MAPK/ERK activation in the basolateral amygdala.

Whereas the neuronal substrates underlying the acquisition of auditory fear conditioning have been widely studied, the substrates and mechanisms mediating the acquisition of fear extinction remain largely elusive. Previous reports indicate that consolidation of fear extinction depends on the mitogen-activated protein kinase/extracellular-signal regulated kinase (MAPK/ERK) signalling pathway and on protein synthesis in the medial prefrontal cortex (mPFC). Based on experiments using the fear-potentiated startle paradigm suggesting a role for neuronal plasticity in the basolateral amygdala (BLA) during fear extinction, we directly addressed whether MAPK/ERK signalling in the basolateral amygdala is necessary for the acquisition of fear extinction using conditioned freezing as a read-out.

CH-stretching overtone spectra of a fast rotating methyl group: 2-CH3 and 2-CHD2 pyridines.

The CH-stretching overtone spectra of the methyl group in gaseous 2-CH(3) and 2-CHD(2) methylpyridines are recorded with conventional Fourier transform near-infrared spectroscopy in the Deltav(CH) = 1-4 regions and by intracavity laser photoacoustic spectroscopy in the Deltav(CH) = 5 and 6 regions. All spectra exhibit a complex structure. They are analyzed with a theoretical model that incorporates, within the adiabatic approximation, the coupling of the anharmonic CH-stretch vibrations described by Morse potentials with the quasifree internal rotation of the methyl group and with isoenergetic combination states involving the six angle deformation modes of the methyl group.