Dual Mechanism of Action of Curcumin in Experimental Models of Multiple Sclerosis

Background: Multiple sclerosis (MS) is characterized by a combination of inflammatory and demyelination processes in the spinal cord and brain. Conventional drugs generally target the autoimmune response, without any curative effect. For that reason, there is a great interest in identifying novel agents with anti-inflammatory and myelinating effects, to counter the inflammation and cell death distinctive of the disease. Methods and results: An in vitro assay showed that curcumin (Cur) at 10 µM enhanced the proliferation of C8-D1A cells and modulated the production of Th1/Th2/Th17 cytokines in the cells stimulated by LPS. Furthermore, two in vivo pathophysiological experimental models were used to assess the effect of curcumin (100 mg/kg). The cuprizone model mimics the de/re-myelination aspect in MS, and the experimental autoimmune encephalomyelitis model (EAE) reflects immune-mediated events. We found that Cur alleviated the neurological symptomatology in EAE and modulated the expression of lymphocytes CD3 and CD4 in the spinal cord. Interestingly, Cur restored motor and behavioral deficiencies, as well as myelination, in demyelinated mice, as indicated by the higher index of luxol fast blue (LFB) and the myelin basic protein (MBP) intensity in the corpus callosum. Conclusions: Curcumin is a potential therapeutic agent that can diminish the MS neuroimmune imbalance and demyelination through its anti-inflammatory and antioxidant effects.     

Comparative study of the texture and structure of aerogel and xerogel sulphated zirconia doped with nickel

Aerogels and xerogels based on sulphated zirconia doped with nickel in the same atomic ratios S/Zr?=?0.5 and Ni/Zr?=?0.1 have been synthesized by sol?Cgel method using two drying ways of the solvent in solid preparation steps. Aerogels obtained by drying in supercritical conditions of solvent stabilize zirconia tetragonal phase even at high calcination temperatures and present a developed surface area, whereas xerogels obtained by ordinary solvent drying in an oven are amorphous. TPR and XPS studies revealed that Ni seems to exist in different species in the two kinds of solids and it is more reducible in aerogels.     

A robust invariant bipolar representation for R 3 surfaces: applied to the face description

In this paper, we intend to introduce a novel invariant curved surface representation under the 3D motion group. It is constructed from the superposition of the two geodesic potentials generated from a given couple of surface points. By sampling this continuous representation, invariant points are extracted from a large neighborhood around these reference points. Different numerical methods are implemented in order to find an efficient approximation in the mean of the shape distance. The inference of small distortions of points positions applied to the reference points is analyzed. We apply the proposed representation to real 3D images. The experimentations are performed on the 3D facial database Bosphorus.     

A new dynamic model of hysteresis in harmonic drives

In this paper, we propose a new dynamic model to describe the hysteresis phenomenon in harmonic drives. The experimental observation of the dynamic torque-displacement relationship for a harmonic drive shows a hysteresis characteristic indicating the simultaneous presence of energy storage and energy dissipation mechanisms. To completely characterize these mechanisms and yet have a simple representation for control, we develop a new hysteresis model using the heredity concept of dynamic systems. This model represents the hysteresis phenomenon by a combination of a nonlinear stiffness component and a nonlinear damping component leading to a mathematically well-posed nonlinear differential equation. The parameters of the model are identified using optimization techniques. We present some important mathematical properties of the model that give insight into model behavior and thus establish a mathematical basis for control. Numerical simulations in comparison with experimental data using our Harmonic Drive Test Apparatus verify the accuracy of the proposed model to represent the complex hysteresis dynamics of harmonic drives.     

Synthesis and characterization of aerogel sulphated zirconia doped with chromium: <Emphasis Type="Italic">n</Emphasis>-hexane isomerization

Mesoporous aerogels based on sulphated zirconia doped with chromium have been synthesized by sol–gel method and dried in hypercritical conditions of the solvent. The characteristic properties of those solids were investigated using many techniques: the XRD, the physisorption of N₂, the IR, the UV-visible and the ESR sprectroscopies. The XRD revealed that ZrO₂ tetragonal phase is stabilized by both sulphate groups and metal at high temperature. The physisorption of N₂ showed that the sol–gel procedure coupled to the drying in the hypercritical conditions of the solvent provides to the zirconia based solids a developed porosity. The important role of chromium metal phase relies on the improvement of n-hexane isomerization by burning-off coke produced over sulphated zirconia. The calcination temperature plays an important role in the stabilization of a particular chromium oxidation state. This state seems to be responsible of the improvement of the catalytic performances of sulphated zirconia doped with chromium.     

Influence of the V + Mo/Al ratio on vanadium and molybdenum speciation and catalytic properties of V–Mo–ZSM-5 prepared by solid-state reaction

V–Mo–ZSM-5 catalysts with various composition prepared by solid-state ion exchange were investigated with respect to their physico-chemical characteristics using chemical analysis, XRD, BET, DRIFT, UV–vis, ²⁷Al MAS-NMR spectroscopy, H₂ TPR and TPD of NH₃. It was found that all the preparations leads to either metal ions sitting at the bridging oxygen of Si–OH–Al or anchored at Si–OH groups or deposited as oxide. These different solids were tested in the selective catalytic reduction of NO_x by ammonia. The main result is that upon addition of small amount of Mo to V–ZSM-5, catalytic performances were enhanced.