Neurofibrillary tangles and plaques are not accompanied by white matter pathology in aged triple transgenic-Alzheimer disease mice

Alzheimer's disease (AD) is a progressive neurodegenerative disorder that is the most common cause of dementia in aging populations. Although senile plaques and neurofibrillary tangles are well-established hallmarks of AD, changes in cerebral white matter correlate with cognitive decline and may increase the risk of the development of dementia. We used the triple transgenic (3xTg)-AD mouse model of AD, previously used to show that white matter changes precede plaque formation, to test the hypothesis that MRI detectable changes occur in the corpus callosum, external capsule and the fornix. T₂-weighted and diffusion tensor magnetic resonance imaging and histological stains were employed to assess white matter in older (11–17 months) 3xTg-AD mice and controls. We found no statistically significant changes in white matter between 3xTg-AD mice and controls, despite well-developed neurofibrillary tangles and beta amyloid immunoreactive plaques. Myelin staining was normal in affected mice. These data suggest that the 3xTg-AD mouse model does not develop MRI detectable white matter changes at the ages we examined.     

A cell-centered Lagrangian hydrodynamics scheme on general unstructured meshes in arbitrary dimension

We describe a cell-centered Godunov scheme for Lagrangian gas dynamics on general unstructured meshes in arbitrary dimension. The construction of the scheme is based upon the definition of some geometric vectors which are defined on a moving mesh. The finite volume solver is node based and compatible with the mesh displacement. We also discuss boundary conditions. Numerical results on basic 3D tests problems show the efficiency of this approach. We also consider a quasi-incompressible test problem for which our nodal solver gives very good results if compared with other Godunov solvers. We briefly discuss the compatibility with ALE and/or AMR techniques at the end of this work. We detail the coefficients of the isoparametric element in the appendix.     

Optical extinction spectroscopy of single silver nanoparticles

The extinction spectrum of single silver nanoparticles with size ranging from 20 to 80 nm is investigated with the spatial modulation spectroscopy technique using either a tunable laser or a white lamp as the broadband source. Results are in good agreement with the prediction of the Mie theory, permitting to extract the nanoparticle size from the measured absolute value of the optical extinction cross-section. In contrast, the deduced refractive index of the nanoparticle environment and the reduction of the electron mean free path show a large dependence on the precise value of the bulk silver dielectric function.     

Beta decay of22O

The beta-gamma spectroscopic study of²²O is presented. This nucleus, produced as a projectile-like fragment from the interaction of a 60 MeV/n⁴⁰Ar beam with a Be target, has been separated by the LISE spectrometer. Several gamma rays from²²O decay have been observed, from which a half-life of (2.25±0.15)s has been determined. Accurate excitation energies have been deduced for several states in²²F. A partial beta decay scheme of²²O has been established. Experimental results have been compared with shell model calculations.     

Nonaffine deformation of inherent structure as a static signature of cooperativity in supercooled liquids

We unveil the existence of nonaffinely rearranging regions in the inherent structures (IS) of supercooled liquids by numerical simulations of model glass formers subject to static shear deformations combined with local energy minimizations. In the liquid state IS, we find a broad distribution of large rearrangements which are correlated only over small distances. At low temperatures, the onset of the cooperative dynamics corresponds to much smaller displacements correlated over larger distances. This finding indicates the presence of nonaffinely rearranging domains of relevant size in the IS deformation, which can be seen as the static counterpart of the cooperatively rearranging regions in the dynamics. This idea provides new insight into possible structural signatures of slow cooperative dynamics of supercooled liquids and supports the connections with elastic heterogeneities found in amorphous solids.     

Light and heavy dansyl reporter groups in food chemistry: amino acid assay in beverages

5-Dimethylamino-1-sulfonyl naphthalene (DNS, commonly referred as dansyl) is a functionality, bearing well-established properties in directing the fragmentation, by mass spectrometry (MS), of the corresponding ionized sulfonylated derivatives. This property is shared also by its labeled analogs. The use of d(0)/d(6) DNS derivatives is now exploited in the application of the well-established isotope dilution mass spectrometric approach in the assay of complex mixtures. A new method for the quantitation of amino acids (AAs) in beverages is therefore presented, which relies on liquid chromatographic separation of their N-dansylated derivatives followed by comparative electrospray tandem MS/MS of the d(0)/d(6) isobaric mixtures. Labeled and unlabeled DNS derivatives of the selected AAs are readily available by microwave-assisted synthetic protocols. The novelty of the method is represented by the use of heavy and light DNS-isotopologue providing suitable reporter groups. Multiple-reaction monitoring has been applied in the assay of AAs in wine, pineapple juice and bergamot juice with good-to-excellent results as proved by both relative standard deviation, lower than 15%, and by the accuracy values in the range 90-110%.     

Extracting Past-Future Vacuum Correlations Using Circuit QED

We propose a realistic circuit QED experiment to test the extraction of past-future vacuum entanglement to a pair of superconducting qubits. The qubit P interacts with the quantum field along an open transmission line for an interval T_{on} and then, after a time-lapse T_{off}, the qubit F starts interacting for a time T_{on} in a symmetric fashion. After that, past-future quantum correlations will have transferred to the qubits, even if the qubits do not coexist at the same time. We show that this experiment can be realized with current technology and discuss its utility as a possible implementation of a quantum memory.     

Statistical approach to the analysis of cell desynchronization data

Experimental measurements on semi-synchronous tumor cell populations show that after a few cell cycles they desynchronize completely, and this desynchronization reflects the intercell variability of cell-cycle duration. It is important to identify the sources of randomness that desynchronize a population of cells living in a homogeneous environment: for example, being able to reduce randomness and induce synchronization would aid in targeting tumor cells with chemotherapy or radiotherapy. Here we describe a statistical approach to the analysis of the desynchronization measurements that is based on minimal modeling hypotheses, and can be derived from simple heuristics. We use the method to analyze existing desynchronization data and to draw conclusions on the randomness of cell growth and proliferation.     

Enhancement of high harmonics generated by field steering of electrons in a two-color orthogonally polarized laser field

We demonstrate enhancement by 1 order of magnitude of the high-order harmonics generated in argon by combining a fundamental field at 1300 nm (10(14) W cm(-2)) and its orthogonally polarized second harmonic at 650 nm (2 × 10(13) W cm(-2)) and by controlling the relative phase between them. This extends earlier work by ensuring that the main effect is the combined field steering the electron trajectory with negligible contribution from multiphoton effects compared to the previous schemes with 800/400 nm fields. We access a broad energy range of harmonics (from 20 eV to 80 eV) at a low laser intensity (far below the ionization saturation limit) and observe deep modulation of the harmonic yield with a period of π in the relative phase. Strong field theoretical analysis reveals that this is principally due to the steering of the recolliding electron wave packet by the two-color field. Our modeling also shows that the atto chirp can be controlled, leading to production of shorter pulses.     

Electrolyte based on fluorinated cyclic quaternary ammonium ionic liquids

Ionic liquids, ILs, based on fluorinated pyrrolidinium and piperidinium ammonium cations and imide anion were prepared and characterized. The physicochemical and electrochemical properties of these ILs including melting point, glass transition and degradation temperatures, viscosity, ionic conductivity, and electrochemical stability were determined and compared to alkyl pyrrolidinium and piperidinium ILs. The incorporation of a CF₃ group instead of a CH₃ induces an increase of the IL viscosity, thus a conductivity decrease. However, good ionic conductivity is obtained with fluorinated pyrrolidinium IL. Cyclic amine ILs with propyl alkyl chain or fluorinated ammonium exhibit very high electrochemical stability toward oxidation. The effect of the addition of LiTFSI on the IL properties was studied with the same methodology.