Differential Radiosensitizing Effect of 50 nm Gold Nanoparticles in Two Cancer Cell Lines.

Radiation therapy is widely used as an anti-neoplastic treatment despite the adverse effects it can cause in non-tumoral tissues. Radiosensitizing agents, which can increase the effect of radiation in tumor cells, such as gold nanoparticles (GNPs), have been described. To evaluate the radiosensitizing effect of 50 nm GNPs, we carried out a series of studies in two neoplastic cell lines, Caco2 (colon adenocarcinoma) and SKBR3 (breast adenocarcinoma), qualitatively evaluating the internalization of the particles, determining with immunofluorescence the number of γ-H2AX foci after irradiation with ionizing radiation (3 Gy) and evaluating the viability rate of both cell lines after treatment by means of an MTT assay.

Enhancing the sensitivity to small phase changes in double-exposure stroboscopic television holography.

We present a new technique for enhancing the sensitivity of double-exposure stroboscopic television holography (TVH) to detect and measure vibrations of small amplitude. The technique is based in the modulation of the phase of the reference beam in synchronism with the vibration of the measurand and derives from a former technique that we originally contrived for phase evaluation. We propose two variants, characterized by the demodulation process used to generate the secondary correlograms, with different behaviors in terms of the sensitivity to the sign of the measurand and of the ease in detecting the presence and shape of the vibration.

Transient Deformation Measurement by Double-Pulsed-Subtraction TV Holography and the Fourier Transform Method.

We report the measurement of transient bending waves with double-pulsed-subtraction TV holography. The correlation fringe patterns are automatically quantitatively analyzed by the application of Fourier methods. A novel optical setup with two different object-beam optical paths is demonstrated for the generation of carrier fringes.

PLD bioactive ceramic films: the influence of CaO-P2O5 glass additions to hydroxyapatite on the proliferation and morphology of osteblastic like-cells.

This work consists on the evaluation of the in vitro performance of Ti6Al4V samples PLD (pulsed laser deposition) coated with hydroxyapatite, both pure and mixed with a CaO-P2O5 glass. Previous studies on immersion of PLD coatings in SBF, showed that the immersion apatite films did not present the usual cauliflower morphology but replicated the original columnar structure and exhibited good bioactivity. However, the influence of glass associated to hydroxyapatite concerning adhesion, proliferation and morphology of MG63 cells on the films surface was unclear.

In vitro testing of Nd:YAG laser processed calcium phosphate coatings.

Nd:YAG laser cladding is a new method for deposition of a calcium phosphate onto metallic surfaces of interest in implantology. The aim of this study was to compare the biologic response of MG-63 human osteoblast-like cells grown on Ti-6Al-4V substrates coated with a calcium phosphate layer applied using different methods: plasma spraying as reference material and Nd:YAG laser cladding as test material. Tissue culture polystyrene was used as negative control.

Structural analysis of calcium phosphate coatings produced by pulsed laser deposition at different water-vapour pressures.

Calcium phosphate coatings have been produced by pulsed laser deposition (PLD) at different water-vapour pressures. Rietveld refinement of X-ray diffraction (XRD) data allows us to determine that the structure of these coatings is apatitic with carbonate substitution for phosphate. The carbonate substitution decreases when the chamber pressure is raised, a fact that has been corroborated by Fourier transform-infrared (FT-IR) spectroscopy.

Hydroxyapatite coatings: a comparative study between plasma-spray and pulsed laser deposition techniques.

A comparative study between hydroxyapatite coatings produced by two different techniques, plasma spray (PS) and pulsed-laser deposition (PLD) was carried out. Plasma spray is currently commercially used for coating dental and orthopaedical implant devices, and pulsed-laser deposition (or laser-ablation deposition) gave good results in the field of high critical temperature superconductive thin films, and is being applied to produce calcium phosphate coatings for biomedical purposes. X-ray diffraction was used to control the crystallinity of the coatings, scanning electron microscopy for the surface and cross-sectional morphology, and the pull test to determine the tensile strength of the coatings.

Influence of the non-bridging oxygen groups on the bioactivity of silicate glasses.

The effect of the composition and bonding configuration of the bioactive silica-based glasses on the initial stage in vitro bioactivity is presented. Information of the IR active Si-O groups of glass in the system SiO(2)-P(2)O(5)-CaO-Na(2)O-K(2)O-MgO-B(2)O(3) was obtained by fourier transform Infrared (FTIR) spectroscopy. Two different bands associated to non-bridging oxygen stretching vibrations (Si-O-1NBO and Si-O-2NBO) and a gradual shifting of the bridging oxygen stretching vibration (Si-O) have been observed and evaluated.

Alloying of hydroxyapatite onto Ti6Al-4V by high power laser irradiation.

In the biomedical field, the synthetic hydroxyapatite [Ca(10)(PO)(4)(OH)(2)], with similarity to the inorganic component of bone but brittle, has been considered as the appropriate coating on stronger implant materials, such as metallic implants, for presenting a surface which is conductive to bone formation. Many industrial and laboratory techniques were developed to apply hydroxyapatite onto metallic substrates, such as electrophoretic deposition, ion sputtering, hot isostatic pressing, pulsed laser deposition and the only widely used method commercially available: plasma spraying. This work presents a new approach on how to bind calcium phosphate (CaP) to the Ti alloy with a well-known technique in the metallurgical field: laser surface alloying, in order to overcome the drawbacks of plasma spraying.

New biomorphic SiC ceramics coated with bioactive glass for biomedical applications.

A new generation of light, tough and high-strength material for medical implants for bone substitutions with a good biological response is presented. The innovative product that fulfills all these requirements is based on biomorphic silicon carbide ceramics coated with a bioactive glass layer. The combination of the excellent mechanical properties and low density of the biomorphic SiC ceramics, used as a base material for implants, with the osteoconducting properties of the bioactive glass materials opens new possibilities for the development of alternative dental and orthopedic implants with enhanced mechanical and biochemical properties that ensures optimum fixation to living tissue.

Micro- and nano-testing of calcium phosphate coatings produced by pulsed laser deposition.

Micro- and nano-testing methods have been explored to study the thin calcium phosphate coatings with high adhesive strength. The pulsed laser deposition (PLD) technique was utilised to produce calcium phosphate coatings on metal substrates, because this type of coatings exhibit much higher adhesive strength with substrates than conventional plasma-sprayed coatings. Due to the limitations of the conventional techniques to evaluate the mechanical properties of these thin coatings (1 microm thick), micro-scratch testing has been applied to evaluate the coating-to-substrate adhesion, and nano-indentation to determine the coating hardness and elastic modulus.

Calcium phosphate coatings obtained by Nd:YAG laser cladding: physicochemical and biologic properties.

The plasma spray (PS) technique is the most popular method commercially in use to produce calcium phosphate (CaP) coatings to promote fixation and osteointegration of the cementless prosthesis. Nevertheless, PS has some disadvantages, such as the poor coating-to-substrate adhesion, low mechanical strength, and brittleness of the coating. In order to overcome the drawbacks of plasma spraying, we introduce in this work a new method to apply a CaP coating on a Ti alloy using a well-known technique in the metallurgical field: laser surface cladding.

Physicochemical properties of calcium phosphate coatings produced by pulsed laser deposition at different water vapour pressures.

Calcium phosphate coatings were produced by pulsed laser deposition from targets of non-stoichiometric hydroxyapatite (Ca/P = 1.70) at a substrate temperature of 485 degrees C and different processing pressures of water vapour: 0.15, 0.

Effect of heat treatment on pulsed laser deposited amorphous calcium phosphate coatings.

Amorphous calcium phosphate coatings were produced by pulsed laser deposition from targets of nonstoichiometric hydroxyapatite (Ca/P = 1.70) at a low substrate temperature of 300 degrees C. They were heated in air at different temperatures: 300, 450, 525 and 650 degrees C.

Measurement range analysis in moiré evaluation Fizeau interferometry.

Fizeau interferograms are evaluated by two-beam phase-stepping algorithms. The sinusoidal intensity profile pattern needed for the application of these algorithms is obtained by low-pass filtering the moiré pattern provided by the superposition of the interferogram onto a Ronchi grid. The phase modulation is performed by the in-plane displacement of the grid by means of a motorized stage.

Phase error calculation in a Fizeau interferometer by Fourier expansion of the intensity profile.

The spectrum of the intensity profile of multiple-beam Fizeau interferograms is presented. Knowledge of this spectrum provides valuable information about the characteristics of Fizeau interferograms, allowing one to calculate the phase error when the Fizeau profile is evaluated by means of two-beam phase-stepping algorithms, as is usual for low-reflectivity coefficients.

Fizeau phase-measuring interferometry using the moiré effect.

The automation of the fringe pattern analysis in Fizeau interferometry combining the moiré effect with the phase-stepping evaluation method is presented. In this case the phase modulator is a Ronchi grid placed at the interferometer image plane yielding a moiré image, and the necessary phase steps are obtained, simply translating the grid in its own plane, perpendicular to the optical axis. A detailed description of the moiré image formation as an incoherent superposition is developed.

Fringe localization control in holographic interferometry.

The practical use of holographic interferometry in nondestructive testing leads to many situations in which the characteristics of the fringe patterns make the observation and subsequent interpretation of the fringes difficult. Fringe control may then be employed to correct the troublesome parameters, the most commonly treated of which is fringe spacing. To gain more powerful control, a novel method is presented here that also permits one to change the localization of the fringe pattern.

Annulling parasitic fringes in real time holographic interferometry: a new method.

A method for annulling parasitic fringes in real time holographicin terferometrya nd its theoreticalj ustification is presented. The main advantage relates to cancellation of nondesired object motions or deformations with experimental simplicity.