Automatic detection of hippocampal atrophy on magnetic resonance images.

An automatic method for identifying hippocampal atrophy on magnetic resonance (MR) images obtained from patients with clinical evidence of temporal lobe epilepsy (TLE) is described. The method is based on the analysis of image intensity differences between patients and controls within a volume of interest (VOI) centred on the hippocampus. The core of the method is a fully automatic signal intensity-based inter-subject image registration technique. In particular, a global affine registration to a reference image is performed, followed by a local affine registration within the VOI. A mask produced by manual segmentation of the mean hippocampus for 30 control subjects enabled investigations to be restricted to a specified region of the VOI approximately corresponding to the hippocampus. Normal variations of hippocampal signal intensity were computed from images obtained for the 30 control subjects. The manual method of hippocampal volumetry, currently an important component of the pre-surgical evaluation of patients with clinical evidence of medically intractable TLE, is used to determine the lower 1st percentile limits of normal hippocampal volume. Hippocampi with volumes below this limit are defined as atrophic. We investigated whether the automatic method can correctly distinguish between 15 patients with significant hippocampal atrophy according to absolute volumes and a further 14 controls. ROC curves enabled evaluation of sensitivity and specificity in respect of an intensity threshold. 100% specificity is required when determining suitability of patients for neurosurgery, resulting in levels of 50% and 70% sensitivity in detecting atrophy in the right and left hippocampus, respectively. We propose that the method can be developed as an automatic screening procedure.     

Hydrogenation Size-Selective Pt/Hollow Beta Catalysts

The aim of the present work is to synthesize a zeolite-based catalyst with a hollow morphology and highly dispersed metal nanoparticles (NPs) encapsulated inside the zeolite micropores. For this purpose, we have studied a treatment using tetraalkylammonium (TAA) bromides for the selective removal of a large Pt particle from the outer surface of a hollow Beta zeolite. TEM analysis reveals that we succeeded in the synthesis of a hollow beta zeolite single crystal with encapsulated particles, with a high dispersion of 50–60 %. The molecular-sieve-type mechanism of the obtained catalysts was evaluated in the model reaction of toluene and mesitylene catalytic hydrogenation. Thanks to the high dispersion. a 10-fold activity enhancement has been obtained with respect to hollow beta zeolites with encapsulated NPs recently described in the literature.     

Periodic reiterated homogenization for elliptic functions

In this paper, we study reiterated homogenization for equations of the form . We assume that a is a Carathéodory function and satisfies some monotonicity and growth conditions and its reiterated unfolding converges almost everywhere to a Carathéodory type function. Under these assumptions, we show that the sequence of solutions converges to the solution of a limit variational problem. In particular this contains the case , where a is periodic in the second and third arguments, and continuous in each argument.     

Addition of Sulphur to Graphene Nanoflakes Using Thermal Plasma for Oxygen Reduction Reaction in Alkaline Medium

A batch process is developed to generate sulphur functionalized graphene nanoflakes (S-GNFs), corresponding to nanoparticles of stacked graphene. The growth and functionalization of the catalysts are done in a single thermal plasma reactor. The GNFs are first grown through the decomposition of methane in the thermal plasma volume followed by homogeneous nucleation of the nanoparticles in the well-controlled recombining plasma stream allowing the 2-dimensional evolution of the nanoparticle morphology. The precursor feeding conditions are then changed to liquid carbon disulphide in order to generate sulphur-based functional groups on the nanoparticles. The plasma conditions and carbon disulphide injection are varied, and samples with tuneable amount of sulphur between 4 and 28 at% are obtained. The functional groups generated include polythiophene polymer partly covering the GNFs, sulphur functionalities implemented directly on the graphitic structure, and traces of orthorhombic sulphur. The S-GNFs exhibit higher electrocatalytic activity toward the oxygen reduction reaction in alkaline medium for the samples containing the highest amounts of sulphur.     

The Necessity of Having a Tetradentate Ligand to Extract Copper(II) Ions from Amyloids

The accumulation of redox-active metal ions, in particular copper, in amyloid plaques is considered to the cause of the intensive oxidation damage to the brain of patients with Alzheimers disease (AD). Drug candidates based on a bis(8-aminoquinoline) tetradentate ligand are able to efficiently extract Cu²⁺ from copper-loaded amyloids (Cu–Aβ). Contrarily, in the presence of a bidentate hydroxyquinoline, such as clioquinol, the copper is not released from Aβ, but remains sequestrated within a Aβ–Cu–clioquinol ternary complex that has been characterized by mass spectrometry. Facile extraction of copper(II) at a low amyloid/ligand ratio is essential for the re-introduction of copper in regular metal circulation in the brain. As, upon reduction, the Cu⁺ is easily released from the bis(8-aminoquinoline) ligand unable to accommodate Cu^I, it should be taken by proteins with an affinity for copper. So, the tetradentate bis(8-aminoquinoline) described here might act as a regulator of copper homeostasis.     

Generalized Lorenz‐Mie Theory for a Sphere with an Eccentrically Located Inclusion,and Optical Chaos

This paper deals with the case when a homogeneous spherical particle (called the inclusion) is embedded at an arbitrary location inside a sphere (called the main or host sphere). Similarly as for previous Generalized Lorenz‐Mie Theories, many applications are expected from this theory, in particular in the field of optical particle characterization. Another interesting prospect concerns the behavior of morphology‐dependent resonances (MDRs). From an electromagnetic point of view, these MDRs correspond to solutions of characteristic equations associated with boundary conditions and lead to internal fields which are concentrated near the rim of the scatterer. It is also shown that this geometrical optics approximation (expressed in terms of rays) is equivalent to a mechanical problem (expressed in terms of trajectories). This mechanical problem leads to chaotic behavior corresponding to optical chaos phenomena in the optical language. We therefore exhibit a class of particles (i) for which the electromagnetic problem is exactly solvable in the framework of a GLMT and (ii) which exhibits chaotic signatures. It is expected that these chaotic signatures would be revealed in salient features of the scattering diagrams, opening the way to refined optical particle characterization in the presence of inhomogeneities.     

Benzodiselenagermoles and spirobisbenzodiselenagermoles

Synthesis of benzodiselenagermoles and bisbenzodiselenagermoles was carried out by transmetallation group 4 → group 14 between diselenophenylenezirconocenes and dialkyl-, diaryl- or alkylaryldichlorogermanes, aryltrichlorogermane or germanium tetrachloride. The new compounds were studied by ¹H, ⁷⁷Se NMR and mass spectrometry. In the case of compounds with substituted phenyl groups, double irradiation and 2D NMR experiments were performed to determine the chemical shifts of the two selenium atoms. The crystal structure of a spirobisbenzodiselenagermole has been established by X-ray diffraction analysis.     

一种新型可配置全光分插复用器的设计

本文提出了一种新型的基于光纤光栅和光纤环形镜的可动态配置的全光分/插复用器,并对这种结构实现单信道、多信道或有选择性地对奇次信道或偶次信道进行下路或直通配置进行了模拟和分析,说明了这种结构的可行性.     

New strategy for the identification of amino acids by TLE and TLC using basic or buffered mobile phases

Summary Direct, simple and reliable means for characterization of the common amino acids, using mixtures of structural analogues of amino acids and combinations of low-voltage electrophoresis (1.04 mol dm^–3 formic acid) and chromatography (tert-butanol/methanol/pyridine/formic acid/water, 33:43:9.6:0.4:20, v/v, methanol/pyridine/formic acid/water, 70:9.6:0.4:20, v/v, or tertpentanol/methylethylketone/pyridine/water, 37.5:37.5:5:20, v/v) on amorphous cellulose thin-layer are given. The efficiency of the procedures is evaluated in various examples.Abbreviations used: TLC = thin-layer chromatography, TLE = thin-layer electrophoresis, TLP = thin-layer plate; other abbreviations: see Table I and end of text.for structural analogues of amino acids and glucosamine, see Table I.