51 research outputs found
Commentary: Luster ceramics: a 9th century AD nanotechnology
Climent-Font, A., "Commentary: Luster ceramics: a 9th century AD nanotechnology", Journal of Nanophotonics, Society of Photo-optical Instrumentation Engineers, 6 (1), 060303 (2012). © Copyright 2012 Society of Photo Optical Instrumentation Engineers. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibite
A multi-ion beam microanalysis approach for the characterization of plasma polymerized allylamine films
EPJ Applied Physics 56. 2 (2011): 24021 with kind permission of The European Physical Journal (EPJ)A full characterization of plasma polymerized biofunctional films requires the use of multi-analytical approaches to determine the chemical composition, topography and potential interaction mechanisms of such films with biomolecules and cells. In this work we aim at underlining the versatility of ion-based techniques to contribute to the chemical characterization of plasma polymerized surfaces. The simultaneous use of energy recoil detection (ERD) and Rutherford backscattering (RBS) spectroscopies with incident He ions is an example of this versatility. Performing sequential measurements and the use of correlating computing tools for ERD-RBS interpretation allows providing in-depth concentration profiles of light elements, including namely hydrogen. More accurate analysis of light elements in polymer films can be increased by looking for particular ions with resonant backscattering responses (i.e., non-Rutherford Scattering). In particular, proton beams of 1.765 MeV are used to increase the detection of C and N, and particular incidence and detector angles to diminish the Si substrate contribution. These analytical tools have been applied to allylamine films and multi-layers crosslinked in a capacitive plasma onto both Si and porous Si substratesWe acknowledge MICINN funding provided by Grant No. MAT2008-06858-C02-01 and grant from Fundación Domingo Martíne
El oro de Guarrazar
Se presentan los primeros resultados analíticos del oro del Tesoro visigodo
de Guarra/ar (Guadamur. Toledo) enmarcado en un proyecto para caracterizar
estas producciones orfebres y su nivel tecnológico. Así mismo, se pretende acla
rar ciertos aspectos sobre su estado actual, como las asociaciones entre materia
les o la identificación de partes originales y reconstruidas. Los análisis de com
posición se han realizado mediante PIXE
The colour and golden shine of early silver Islamic lustre
A selection of lustres including 9th century AD polychrome and 10th century AD
monochrome Abbasid lustres from Iraq, and 10th to 12th centuries AD Fatimid lustres from Egypt
and Syria is studied in the present paper. The selection is based on previous studies that
demonstrated that all of them contain metal silver nanoparticles and copper, which, when present,
appears either as Cuþ or Cu2þ dissolved in the glaze. They show different colours, green, yellow,
amber, and brown, and may also show or lack a golden-like reflectivity, which results mainly from
average size and concentration in the layer of the silver nanoparticles. In this paper, a depth profile
composition of the lustre layers is determined using Rutheford Backscattering Spectroscopy,
allowing the determination of the total silver content, concentration of silver, copper to silver ratio,
and thickness of the lustre layers. We show that the enhanced golden-like reflectivity occurs only
for layers with a high concentration of silver, and that the addition of PbO to the alkaline glaze
helps the formation of more concentrated layers. The results obtained provide new hints concerning the lead enrichment of the glazes during this period.Peer ReviewedPostprint (published version
Technology of production of Syrian lustre (11th to 13th century)
Lustre is a decoration consisting of a surface layer of silver and copper metal nanoparticles, a few hundreds of nanometres thick and incorporated into the glaze. It shows a colourful metallic and iridescent appearance which makes use of the quantum confined optical response of the metallic nanoparticles. Three apparently unrelated lustre decorations, yellow-orange golden (Tell Minis), a dark brown-reddish with iridescences (Raqqa) and yellow-brown golden (Damascus) were produced in the same area in successive periods over tin and lead-free glazes which is known to require specific strategies to obtain a metallic shiny lustre. The composition and nanostructure of the lustre layers are analysed and the materials and specific firing conditions followed in their production determined. The optical properties of the lustre layers have been analysed in terms of the nanostructure obtained and correlated to the specific processing conditions.Peer ReviewedPostprint (author's final draft
Optical properties and refractive index sensitivity of reactive sputtered oxide coatings with embedded Au clusters
The following article appeared in Journal of Applied Physics 115.6 (2014): 063512 and may be found at http://scitation.aip.org/content/aip/journal/jap/115/6/10.1063/1.4861136In the present study, nanocomposite coatings of Au clusters embedded in two different oxides, TiO2 and Al2O3, were synthesized using pulsed DC magnetron sputtering. The depositions were carried out in three steps, by depositing the oxide, the Au clusters, and again the oxide. The deposition time of the Au clusters was varied in order to achieve different cluster sizes, morphologies, and nanocomposite topographies. The structure, microstructure, morphology, and the optical properties of the coatings were studied. With the increase in Au content, red-shifted surface plasmon resonance (SPR) peaks with higher intensity and increased widths were observed due to changes in the metal clusters sizes and morphology and due to interparticle effects. In order to relate the peculiar SPR extinction bands with the different clusters shapes and distributions, a simulation of the optical properties of the nanocomposites was performed making use of the Renormalized Maxwell-Garnett approach. A theoretical study concerning the refractive index sensitivity was made in order to predict the optimal coatings parameters for sensing experiments. The increased surface area and the strong SPR extinction bands make these coatings suitable for gas sensing and also catalysis, albeit many other application fields can be envisaged.This research was sponsored by FEDER funds through the program COMPETE, Programa Operacional Factores de Competitividade, by national funds through FCT, Fundacao para a Ciencia e a Tecnologia, under the Projects PEst-C/EME/UI0285/2013 and CENTRO-07-0224-FEDER-002001 (Mais Centro SCT_2011_02_001_4637), and through the Spanish Ministry of Science and Innovation by Projects FUNCOAT CSD2008-00023 and AIB2010PT-00241. R.E.G. wishes also to thank the MCINN for the financial support within the Ramón y Cajal programme. Funding by the European Community through Project Nano4Color is gratefully acknowledged
Composition, nanostructure, and optical properties of silver and silver-copper lusters
Lusters are composite thin layers of coinage metal nanoparticles in glass displaying peculiar optical
properties and obtained by a process involving ionic exchange, diffusion, and crystallization. In
particular, the origin of the high reflectance (golden-shine) shown by those layers has been subject of
some discussion. It has been attributed to either the presence of larger particles, thinner multiple
layers or higher volume fraction of nanoparticles. The object of this paper is to clarify this for which
a set of laboratory designed lusters are analysed by Rutherford backscattering spectroscopy,
transmission electron microscopy, x-ray diffraction, and ultraviolet-visible spectroscopy. Model
calculations and numerical simulations using the finite difference time domain method were also
performed to evaluate the optical properties. Finally, the correlation between synthesis conditions,
nanostructure, and optical properties is obtained for these materials
Nanostructured porous silicon micropatterns as a tool for substrate-conditioned cell research
The localized irradiation of Si allows a precise patterning at the microscale of nanostructured materials such as porous silicon (PS). PS patterns with precisely defined geometries can be fabricated using ion stopping masks. The nanoscale textured micropatterns were used to explore their influence as microenvironments for human mesenchymal stem cells (hMSCs). In fact, the change of photoluminescence emission from PS upon aging in physiological solution suggests the intense formation of silanol surface groups, which may play a relevant role in ulterior cell adhesion. The experimental results show that hMSCs are sensitive to the surface micropatterns. In this regard, preliminary β-catenin labeling studies reveal the formation of cell to cell interaction structures, while microtubule orientation is strongly influenced by the selective adhesion conditions. Relevantly, Ki-67 assays support a proliferative state of hMSCs on such nanostructured micropatterns comparable to that of standard cell culture platforms, which reinforce the candidature of porous silicon micropatterns to become a conditioning structure for in vitro culture of hMSCsThe authors gratefully acknowledge the financial support from MICINN under research project MAT2008-06858-C02-01/NAN and Comunidad de Madrid (Spain) under Project Microseres. Technical support from L García Pelayo is greatly appreciate
Engineering of silicon surfaces at the micro- and nanoscales for cell adhesion and migration control
The engineering of surface patterns is a powerful tool for analyzing cellular communication factors involved in the processes of adhesion, migration, and expansion, which can have a notable impact on therapeutic applications including tissue engineering. In this regard, the main objective of this research was to fabricate patterned and textured surfaces at micron- and nanoscale levels, respectively, with very different chemical and topographic characteristics to control cell–substrate interactions. For this task, one-dimensional (1-D) and two-dimensional (2-D) patterns combining silicon and nanostructured porous silicon were engineered by ion beam irradiation and subsequent electrochemical etch. The experimental results show that under the influence of chemical and morphological stimuli, human mesenchymal stem cells polarize and move directionally toward or away from the particular stimulus. Furthermore, a computational model was developed aiming at understanding cell behavior by reproducing the surface distribution and migration of human mesenchymal stem cells observed experimentally
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