CNRS Nanosciences Research Laboratory

Reims, France

CNRS Nanosciences Research Laboratory

Reims, France
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Troyon M.,CNRS Nanosciences Research Laboratory | Abbes F.,University of Reims Champagne Ardenne | Garcia Guzman J.A.,Pontifical Bolivarian University
Scanning | Year: 2012

Kaupp and Naimi-Jamal (2010) claimed that the analysis of published loading curves reveals the exponent 3/2 to the depth for nanoindentations with sharp pyramidal or conical tips. To demonstrate this, they plotted the load vs. the penetration depth to the power 3/2. We show, through examples, the authors' assertion is not credible because the methodology used is misleading and it cannot be asserted that the exponent 3/2 has a universal validity that applies to all kinds of materials. © Wiley Periodicals, Inc.

Mouetsi S.,University of Oum El Bouaghi | El Hdiy A.,CNRS Nanosciences Research Laboratory
Journal of Applied Physics | Year: 2013

The 1/f noise is investigated in an epitaxial AlGaAs/GaAs/AlGaAs heterostructure in the temperature range of [4-300 K]. The sample is biased at very low voltage to avoid velocity saturation at low temperature. Hooge parameters are determined at very low frequency assuming the absence of correlation between existing noise sources. These parameters are weakly fluctuating but do not show clear variation with temperature; αH varies in the range of 10-5 to 10-2, which are higher than theoretical values based on the mobility fluctuations. γ remains close to unity. αH and γ values suggest that the 1/f noise originates from the mobility fluctuation due to the lattice scattering, but the difference between theoretical and experimental αH suggests the existence of the noise originating from electron number fluctuations. © 2013 AIP Publishing LLC.

Kadota K.,CNRS Nanosciences Research Laboratory
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2016

Design For Manufacturing (DFM) where the state-of-the-art nano-devices of the sub-20nm node to a subject, for each of the technology has been intricately sophisticated, comprehensive optimization to predict the performance of the device came become very important. [1] To get effective solutions on these subjects, one of the lithographic key is a nano Optical Proximity Correction (OPC) control with SMO technology, and another is TCAD approach using the most advanced computer simulations. And, it is very important to obtain DFM solutions by integrating both. On the other hand, to meet the needs of low-voltage drive and the characteristic variability reduction, in order to obtain a state-of-the-art device performance, the Fin-type transistors are introduced globally as the mainstream because of wider process control margin. This paper, from the point of view of the sub-20nm node DFM, the simulation are conducted on ArF-imm. technology with SMO in SPT, DPT and QPT on TachyonTM [2], and the guideline of design rules are obtained. Furthermore, the simulated transistor pattern shape are directly migrated into TCAD process flow on HyENEXSSTM [3]. Then calculated I-V characteristics on 6 transistors under the various parameters on TCAD, and finally summarized Static Noise Margin (SNM) of SRAMs. Here, various parameters that determine the performance of SRAMs (Fin width, height, angle, dopant concentrations, electric field strength, work function, drive voltage, and operation speed) are intentionally varied and calculated on the TCAD. This computational method is highly sophisticated DFM technology to predict for the leading-edge nano-devices toward for the sub-20nm nodes era [4] [5] [6] [7]. © 2016 SPIE.

Bayan S.,CNRS Nanosciences Research Laboratory | Das U.,CNRS Nanosciences Research Laboratory | Mohanta D.,CNRS Nanosciences Research Laboratory
European Physical Journal D | Year: 2011

Barbules of the peacock feather have been used as the natural template for developing assemblies of zinc oxide (ZnO) nanospheres. The different colored barbules consisting of various photonic crystals (extracted from eye-pattern) were characterized in terms of the stop-bands identified in the respective Reflectance spectra. The stop-bands of the photonic crystals are found to get red-shifted after the loading of ZnO nanospheres and was reasoned to the modification of photonic band gap. The ZnO nanosphere decorated barbules show well defined photoluminescence response with dominant defect related emission of ZnO. The artificially grown inorganic structures on natural templates form a basis of new hybrid system that can help in exploiting photonic band gap engineering and light wave modulation with high selectivity. © 2010 EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg.

Guillard T.,Reims University Hospital Center | Guillard T.,University of Reims Champagne Ardenne | Lebreil A.-L.,University of Reims Champagne Ardenne | Hansen L.H.,Reims University Hospital Center | And 9 more authors.
Antimicrobial Agents and Chemotherapy | Year: 2015

We developed a two-step PCR-based strategy to detect genes encoding OqxAB, allowing a specific assignment of Tn6010-associated oqxAB in Enterobacteriaceae. Chromosomal location in this setup was confirmed by hybridization with I-CeuI-restricted genomes. This approach led us to find that Klebsiella sp. and Raoultella sp. reference strains chromosomally carried oqxAB. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Khanna P.K.,Indian Defence Institute of Advanced Technology | Kate K.,CNRS Nanosciences Research Laboratory | Dhanabalan K.,Indian Defence Institute of Advanced Technology | Banerjee S.,Indian Defence Institute of Advanced Technology | And 3 more authors.
Journal of Nanoscience and Nanotechnology | Year: 2012

Herein we describe synthesis of ZnO nanoparticles by using alkaline solution of ZnX 2 (X = NO 3, Cl) under ultrasound energy of 20 KHz. The reaction can be completed in about 1-2 hours. As prepared powders were analyzed by XRD measurement to find that the product is hexagonal phase pure ZnO. UV-Visible measurement of aq. solution showed absorption band at ̃365 nm and photoluminescence (PL) indicated multiple bands in visible region due to deep traps owing to high temperature sintering. The hydrophilicity can be imparted by use of a suitable polyelectrolyte. Freshly prepared samples showed good dispersion in aqueous and alcoholic medium. The thick films derived from the ZnO nano-particles showed excellent sensing for hydrogen sulphide gas. Copyright © 2012 American Scientific Publishers.

Callewaert M.,CNRS Institute of Molecular Chemistry - Reims | Dukic S.,French National Center for Scientific Research | Van Gulick L.,French National Center for Scientific Research | Vittier M.,French National Center for Scientific Research | And 4 more authors.
Journal of Biomedical Materials Research - Part A | Year: 2013

Etoposide (VP-16) is a hydrophobic anticancer agent inhibiting Topoisomerase II, commonly used in pediatric brain chemotherapeutic schemes as mildly toxic. Unfortunately, despite its appropriate solubilization in vehicle solvents, its poor bioavailability and limited passage of the blood-brain barrier concur to disappointing results requiring the development of new delivery system forms. In this study, etoposide formulated as a parenteral injectable solution (Teva®) was loaded into all-biocompatible poly(lactide-co-glycolide) (PLGA) or PLGA/P188-blended nanoparticles (size 110-130 nm) using a fully biocompatible nanoprecipitation technique. The presence of coprecipitated P188 on encapsulation efficacies and in vitro drug release was investigated. Drug encapsulation was determined using HPLC. Inflammatory response was checked by FACS analysis on human monocytes. Cytotoxic activity of the various simple (Teva®) or double (Teva®-loaded NPs) formulations was studied on the murine C6 and F98 cell lines. Obtained results suggest that, although noninflammatory neither nontoxic by themselves, the use of PLGA and PLGA/P188 nanoencapsulations over pre-existing etoposide formulation could induce a greatly improved cytotoxic activity. This approach demonstrated a promising perspective for parenteral delivery of VP16 and potential development of a therapeutic entity. © 2012 Wiley Periodicals, Inc.

PubMed | University of Reims Champagne Ardenne and CNRS Nanosciences Research Laboratory
Type: Journal Article | Journal: Neurobiology of aging | Year: 2015

The long complement receptor type 1 (CR1) isoform, CR1*2 (S), has been identified as being associated with Alzheimers disease (AD) risk. We aimed to analyze the phenotypic structural and expression aspects (length and density) of CR1 in erythrocytes of 135 Caucasian subjects (100 AD and 35 controls). CR1 length polymorphism was assessed at protein and gene levels using Western blot and high-resolution melting, respectively. CR1 sites on erythrocytes were enumerated by flow cytometry. CR1 gene analysis, spotting the rs6656401 and rs3818361 polymorphisms, was performed by pyrosequencing. The CR1 density was significantly lower in AD patients expressing the CR1*2 isoform compared with the controls (p = 0.001), demonstrating lower expression of CR1 in CR1*2 carriers. Our data suggested the existence of silent CR1 alleles. Finally, rs6656401 and rs3818361 were strongly associated with CR1 length polymorphism (p < 0.0001). These observations indicate that AD susceptibility is associated with the long CR1 isoform (CR1*2), albeit at a lower density, suggesting that AD results from insufficient clearance of plaque deposits rather than increased inflammation.

PubMed | CNRS Nanosciences Research Laboratory
Type: | Journal: Methods in molecular biology (Clifton, N.J.) | Year: 2014

The cell nucleus is a crowded volume in which the concentration of macromolecules is high. These macromolecules sequester most of the water molecules and ions which, together, are very important for stabilization and folding of proteins and nucleic acids. To better understand how the localization and quantity of water and ions vary with nuclear activity, it is necessary to study them simultaneously by using newly developed cell imaging approaches. Some years ago, we showed that dark-field cryo-Scanning Transmission Electron Microscopy (cryo-STEM) allows quantification of the mass percentages of water, dry matter, and elements (among which are ions) in freeze-dried ultrathin sections. To overcome the difficulty of clearly identifying nuclear subcompartments imaged by STEM in ultrathin cryo-sections, we developed a new cryo correlative light and STEM imaging procedure. This combines fluorescence imaging of nuclear GFP-tagged proteins to identify, within cryo ultrathin sections, regions of interest which are then analyzed by STEM for quantification of water and identification and quantification of ions. In this chapter we describe the new setup we have developed to perform this cryo-correlative light and STEM imaging approach, which allows a targeted nano analysis of water and ions in nuclear compartments.

PubMed | University of Reims Champagne Ardenne and CNRS Nanosciences Research Laboratory
Type: Journal Article | Journal: PloS one | Year: 2016

Many studies have demonstrated changes in the levels of several ions during apoptosis, but a few recent studies have reported conflicting results concerning the changes in water content in apoptotic cells. We used a correlative light and cryo-scanning transmission electron microscopy method to quantify water and ion/element contents simultaneously at a nanoscale resolution in the various compartments of cells, from the onset to the end of apoptosis. We used stably transfected HeLa cells producing H2B-GFP to identify the stages of apoptosis in cells and for a targeted elemental analysis within condensed chromatin, nucleoplasm, mitochondria and the cytosol. We found that the compartments of apoptotic cells contained, on average, 10% more water than control cells. During mitochondrial outer membrane permeabilization, we observed a strong increase in the Na+ and Cl- contents of the mitochondria and a strong decrease in mitochondrial K+ content. During the first step in apoptotic volume decrease (AVD), Na+ and Cl- levels decreased in all cell compartments, but remained higher than those in control cells. Conversely, during the second step of AVD, Na+ and Cl- levels increased considerably in the nucleus and mitochondria. During these two steps of AVD, K+ content decreased steadily in all cell compartments. We also determined in vivo ion status during caspase-3 activity and chromatin condensation. Finally, we found that actinomycin D-tolerant cells had water and K+ contents similar to those of cells entering apoptosis but lower Na+ and Cl- contents than both cells entering apoptosis and control cells.

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