Entity

Time filter

Source Type

Villeneuve-la-Rivière, France

Ayat M.,University of Science and Technology Houari Boumediene | Boarino L.,INRIM - Istituto Nazionale di Ricerca Metrologica | Boukherroub R.,Interdisciplinary Research Institute IRI | Kechouane M.,University of Science and Technology Houari Boumediene
Nanoscale Research Letters | Year: 2014

In this work, we report the fabrication of ordered silicon structures by chemical etching of silicon in vanadium oxide (V2O5)/hydrofluoric acid (HF) solution. The effects of the different etching parameters including the solution concentration, temperature, and the presence of metal catalyst film deposition (Pd) on the morphologies and reflective properties of the etched Si surfaces were studied. Scanning electron microscopy (SEM) was carried out to explore the morphologies of the etched surfaces with and without the presence of catalyst. In this case, the attack on the surfaces with a palladium deposit begins by creating uniform circular pores on silicon in which we distinguish the formation of pyramidal structures of silicon. Fourier transform infrared spectroscopy (FTIR) demonstrates that the surfaces are H-terminated. A UV-Vis-NIR spectrophotometer was used to study the reflectance of the structures obtained. A reflectance of 2.21% from the etched Si surfaces in the wavelength range of 400 to 1,000 nm was obtained after 120 min of etching while it is of 4.33% from the Pd/Si surfaces etched for 15 min. © 2014, Ayat et al.; licensee Springer. Source


Ayat M.,University of Science and Technology Houari Boumediene | Boarino L.,INRIM - Istituto Nazionale di Ricerca Metrologica | Boukherroub R.,Interdisciplinary Research Institute IRI
ECS Transactions | Year: 2015

In this work we report the fabrication of ordered macroporous silicion structures by chemical etching of silicon in vanadium oxide (V2O5) and hydrofluoric acid (HF) solution. The effects of the different etching parameters, including the etching time and the presence of metal catalyst film deposition (Pd, Ag), on the morphologies and the optical properties of the etched Si surfaces were studied. It has been found that the morphology depends on the etching time and on the presence and the type of the catalyst. The results show that the attack of the silicon surface coated with Palladium or Silver deposit begins by creating circular pores. In addition, long etching time leads to the formation of porous pyramidal structures inside the macropores. A reflectance around 1,64% and a contact angle of 148° for the Ag/Si structures were observed. © The Electrochemical Society. Source


Corbel C.,French National Center for Scientific Research | Corbel C.,University of Southern Brittany | Corbel C.,University of California at Santa Barbara | Zhang B.,North China Electrical Power University | And 9 more authors.
Chemistry and Biology | Year: 2015

Cyclin-dependent kinase 5 (CDK5) is a multifunctional enzyme that plays numerous roles, notably in brain development. CDK5 is activated through its association with the activators, p35 and p39, rather than by cyclins. Proteolytic procession of the N-terminal part of its activators has been linked to Alzheimer's disease and various other neuropathies. The interaction with the proteolytic product p25 prolongs CDK5 activation and modifies the substrate specificity. In order to discover small-molecule inhibitors of the interaction between CDK5 and p25, we have used a bioluminescence resonance energy transfer (BRET)-based screening assay. Among the 1,760 compounds screened, the generic drug tamoxifen has been identified. The inhibition of the CDK5 activity by tamoxifen was notably validated by monitoring the phosphorylation state of tau protein. The study of the molecular mechanism of inhibition indicates that tamoxifen interacts with p25 to block the CDK5/p25 interaction and pave the way for new treatments of tauopathies. © 2015 Elsevier Ltd. All rights reserved. Source


Saad N.,CNRS Institute of Electronics, Microelectronics and Nanotechnology | Saad N.,Lebanese University | Dufour R.,University of Lille Nord de France | Dufour R.,Interdisciplinary Research Institute IRI | And 11 more authors.
Journal of Applied Physics | Year: 2012

In this work, we propose acoustic characterization as a new method to probe wetting states on a superhydrophobic surface. The analysis of the multiple reflections of a longitudinal acoustic wave from solid-liquid and solid-vapor interfaces enables to distinguish between the two well known Cassie-Baxter and Wenzel wetting configurations. The phenomenon is investigated experimentally on silicon micro-pillars superhydrophobic surfaces and numerically using a finite difference time domain method. Numerical calculations of reflection coefficients show a good agreement with experimental measurements, and the method appears as a promising alternative to optical measurement methods. © 2012 American Institute of Physics. Source


Madani A.,Ferhat Abbas University Setif | Nessark B.,Ferhat Abbas University Setif | Boukherroub R.,Interdisciplinary Research Institute IRI | Chehimi M.M.,University Paris Diderot
Journal of Electroanalytical Chemistry | Year: 2011

PPy/CdS composite films made from polypyrrole (PPy) with embedded semiconductor (CdS) quantum dots were obtained by electropolymerization of pyrrole in the presence the CdS nanoparticles dispersed in the electrolytic aqueous solution. For the characterization of the modified surface electrode by PPy-CdS, the scan electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and UV-visible were used. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) have been used to investigate the electrochemical behaviour of the resulting materials. The illumination effects are also observed in the reduced form of the polymer. This study showed that the presence of CdS nanoparticles in the polypyrrole film improves the optical properties of PPy via a simple preparation method and show that these films have potential in the photoelectrochemical applications such as photovoltaic cells. © 2010 Elsevier B.V. All rights reserved. Source

Discover hidden collaborations