National Institute Of Materials Physics - Romania

The electrodeposition process of Eosin Y/ZnO:Mn as films and nanowires performed using a solution containing zinc and manganese nitrates + lactic acid mixture was studied by linear voltammetry. The films and wires grown by polarization at -1.1 V/SCE electrode potential were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDX), and X-ray photoelectron spectroscopy (XPS). Additionally, the Eosin Y presence was evidenced by optical measurements as absorption and photoluminescence spectroscopy. The manganese content in films depends on the nature of support electrode used. On the other hand, the presence of Eosin Y species in the deposition bath increased significantly the manganese concentration in the ZnO:Mn nanowires electrodeposited at -1.1 V/SCE.

Sucrose is a natural osmolyte accumulated in the cells of organisms as they adapt to environmental stress. In vitro sucrose increases protein stability and forces partially unfolded structures to refold. Thin films of sucrose (C12H22O11) were deposited on thin cut glass substrates by the thermal evaporation technique (P similar to 10(-5) torr). Characteristics of thin films were put into evidence by Fourier Transform Infrared Spectroscopy (FTIR), X-ray Photoelectron Spectroscopy (XPS), scanning electron microscopy (SEM), and differential thermal analysis and thermal gravimetric analysis (TG/DTA). The experimental results confirm a uniform deposition of an adherent layer. In this paper we present a part of the characteristics of sucrose thin films deposited on glass in medium vacuum conditions, as a part of a culture medium for osteoblast cells. Osteoblast cells were used to determine proliferation, viability, and cytotoxicity interactions with sucrose powder and sucrose thin films. The osteoblast cells have been provided from the American Type Culture Collection (ATCC) Centre. The outcome of this study demonstrated the effectiveness of sucrose thin films as a possible nontoxic agent for biomedical applications.

The aim of this paper is the preparation and characterization of hydroxyapatite doped with europium (Eu3+, Eu:Hap). The nanopowders were obtained by coprecipitation method and analyzed through infrared spectroscopy (FT-IR) and Fourier transform Raman spectroscopy (FT-Raman). The preliminary results reveal the nanometric dimension of the particles and indicate that Eu3+ has been introduced into the framework of HAp. The Eu concentration effects of nano Eu: HAp were studied on human osteoblast MG 63 cells in vitro. Our results demonstrate that cell proliferation is not related to the Eu concentration in the HAp particles. This work provides an interesting view of the role of nano Eu: HAp as ideal biomedical materials in future clinical applications.

Europium doped hydroxyapatite (Eu:HAp) nanocristalline powders was synthesized by co-precipitation method by setting the atomic ratio of Eu/[Eu + Ca] at 0% and 2% and [Ca+Eu] /P at 1.67. The structural properties were characterized by X-ray diffraction (XRD). Nitrogen adsorption-desorption isotherms were obtained on different samples using BET method. The X-ray diffraction analysis revealed that hydroxyapatite is the unique crystalline constituent of all the samples, indicating that Eu has been successfully inserted into the HAp lattice. Based on N-2 adsorption-desorption isotherms investigation, the pore size, surface area and pore volume of europium doped hydroxyapatite are 16.57 nm, 115.06 m(2)/g and 0.48 cm(3)/g.

For the first time we presented the preliminary results of biocompatibility studies on bioceramic hydroxyapatite powders doped with europium Ca10-xEux(PO4)(6)(OH)(2), with 0.01 <= x(Eu) <= 0.2 prepared at low temperature by a simple coprecipitation approach. The X-ray diffraction (XRD) studies revealed the characteristic peaks of hydroxyapatite in each sample. No evidence for additional crystalline phases was found, proving the complete substitution of Eu in the HAp lattice in the whole range of concentrations. The scanning electron microscopy (SEM) observations suggest that these materials present a little different morphology, which reveals a homogeneous aspect of the synthesized particles for all samples. The PL investigations shown the PL intensity changed considerably by varying the x(Eu). The value of x(Eu) in the hydroxyapatite formula has almost no effect on the wavelength of emission peaks. In order to test Hap_Eu biocompatibility, the effect of europium substituted hydroxyapatite nanocristalline powders with different x(Eu) on cell viability and proliferation of HEK293 cell line were evaluated. The in vitro investigation showed no significant decrease of viability of HEK293 cell line and low levels of intracellular lipid peroxidation in the Hap_Eu treated cells. In conclusion, the results suggest that Eu doped HAp has low toxicity and exhibit a good biocompatibility.

We report on the development of a modified gas diffusion layer for fuel cells consisting of a simple or teflonized carbon cloth pulsed laser deposited with metal oxide nanostructures designed to operate both as co-catalyst, and oxidic support for other electrochemically active catalysts. We selected TiO2, ZnO and Al2O3 doped (2 wt.%) ZnO which were uniformly distributed over the surface of gas diffusion layers in order to improve the catalytic activity, stability and lifetime, and reduce the production costs of proton exchange membrane fuel cells. We evidenced by scanning electron microscopy and energy dispersive spectroscopy that our depositions consisted of TiO2 nanoparticles while in the case of ZnO and Al2O3 doped (2 wt.%) ZnO transparent quasi-continuous films were synthesized. (C) 2009 Elsevier BM. All rights reserved.

Iron oxide nanoparticles were synthesized in the presence of dextrin. The adsorption process of different dextrin molecules onto the surface of in water dispersed iron-oxide nanoparticles has been investigated to optimize the preparation of iron oxide magnetic fluids. An average iron oxide core size of 8 nm was found by transmission electron microscopy (TEM) for the samples. Scanning electron microscopy (SEM) micro-structural studies revealed a spherical shape of the particles. X-ray phase analysis revealed spinel structure of the iron oxide particles. The attachment of the dextrin on the particle surface was investigated by FTIR spectrometry. The dextrin coated iron oxide nanoparticles were used as targets in Pulsed Laser Deposition (PLD) experiments for thin films synthesis.

In this study the Matrix Assisted Pulsed Laser Evaporation (MAPLE) technique was used to prepare thin films from a low melting point (< 100 degrees C) organic compound (benzil). Optical properties of the films have been investigated by UV-VIS, FTIR and PL spectroscopy. Details about crystallinity were obtained by XRD measurements. FTIR spectra have confirmed the preservation of the chemical structure of the compound during the deposition process. SEM and AFM investigation have evidenced a topography of the MAPLE deposited films characterized by different grain size depending on the deposition conditions. Second harmonic generation measurements have revealed that the MAPLE deposited benzil films have preserved the optical nonliniar properties of the bulk crystalline benzil.

As2S3 on Ag heterostructures deposited onto microscope glass substrates have been prepared. The quality of the hetero-structures has been investigated by careful analysis of the scanning electron microscope pictures taken on the native cross-sections, produced after the vacuum deposition sequence and various green laser irradiation times. The As2S3 layer is not uniformly grown, but reveals a columnar-like structure and multi-scale aggregation.

The aim of this study is to investigate the influence of the different media, e.g. air, water, CCl4 (carbon tetrachloride) and C2Cl3F3 (tricloro-trifluoro-ethane), when irradiating a Si (100) substrate, with a 200 femtosecond (fs) laser pulses of a Ti:sapphire laser operating at 775 nm. Various micro and nanomorphologies could be achieved by changing the media, the laser pulse energy and the number of pulses. It is shown that the resulting Si (100) surface presents a regulated morphology in air consisting of parallel ripples and the formation of regular arrays of submicrometer spikes on Si (100) in CCl4 and C2Cl2F3, respectively. Irradiation of a Si (100) substrate immersed in water creates a regularly structured surface but it doesn't facilitate the spikes formation. The potential use of the patterned Si substrates as model scaffolds for the systematic exploration of the role of 3D micro/nano morphology on cell adhesion and growth is envisaged.