Dual pulsed laser deposition of Ag nanoparticles on calcium phosphate coatings for biomedical applications.

Pulsed laser deposition (PLD) represents a promising bottom-up methodology for the synthesis and transference of nanoparticles to the surface of a biomedical device. Silver (Ag) nanoparticles directly incorporated on the metallic implant emerge as an alternative strategy for local action against prosthetic joint-associated infections. In the present research, a dual sequential PLD process is proposed to obtain a bilayer coating with (1) a bio-derived calcium phosphate (CaP) layer, to provide osteointegrative properties and (2) the controlled growth of the Ag nanoparticles over it, ranging the number of laser pulses from 100 to 500. The characterization by SEM, EDS, TEM, XPS and AFM revealed the uniform deposit of Ag rounded nanoparticles, with a narrow mean size distribution, in the original non-oxidized metallic state. Moreover, given the evidences from XPS and AFM techniques, the occurrence of a coalescence phenomenon from 400 pulses onwards was proposed together with the expected positive linear relation between the number of pulses and Ag contribution with a deposition rate of 0.05 at. % of Ag per pulse. Conversely, the decrease in roughness as the Ag content increased was also verified. Finally, the expected bacteriostatic activity for these PLD deposited metallic state Ag nanoparticles against the bacterial strainStaphylococcus aureuswas confirmed. Moreover, the evaluation of the osteoblast-like MG-63 cells viability on the Ag(100-500)-CaP coatings revealed a significant increased proliferation (p > 0.05) on the Ag100-CaP coating compared to the control (Ag0-CaP). When same coating was evaluated againstS. aureusthe effect was not significant. The possibility of modulating the amount of nanoparticles in the bilayer coating to obtain a greater or lesser effect in combination with CaP was revealed.

A methodology to quantify the differences between alternative methods of heart rate variability measurement.

This work proposes a systematic procedure to report the differences between heart rate variability time series obtained from alternative measurements reporting the spread and mean of the differences as well as the agreement between measuring procedures and quantifying how stationary, random and normal the differences between alternative measurements are. A description of the complete automatic procedure to obtain a differences time series (DTS) from two alternative methods, a proposal of a battery of statistical tests, and a set of statistical indicators to better describe the differences in RR interval estimation are also provided. Results show that the spread and agreement depend on the choice of alternative measurements and that the DTS cannot be considered generally as a white or as a normally distributed process. Nevertheless, in controlled measurements the DTS can be considered as a stationary process.

[Obtaining of serum (antibodies) of antitrophozoites of Giardia lamblia and non-specific factors. A practical method]. / Obtención de sueros (anticuerpos) de antitrofozitos de Giardia lamblia y elementos inespecíficos. Un método práctico.

According to some authors, the nonspecific elements belong to Candida albicans morphologic variables, and according to others, they represent an evolutive stage or are the result of Giardia lamblia. An immunitary methodology is developed in experimental animals combining intramuscular, intravascular and intraperitoneal pathways with soluble substances and extracts which can be absorbed in aluminium hydroxide of Giardia lamblia and nonspecific elements trophocytes. Sera (antibodies) to these organisms are obtained.

[Antigens from Giardia lamblia trophozoites and cysts. Detection and immunoallergic evaluation]. / Antígenos de trofozitos y quistes de Giardia lamblia. Obtención y evaluación immunoalérgica.

A suitable technique for the preparation of antigen extracts from Giardia lamblia trophozoites and cysts is described. The immunoallergic characteristics of the antibodies obtained with these extracts were studied using in vivo and in vitro tests in experimental animals and 50 healthy individuals. It was proved that the human is able to produce antibodies to Giardia lamblia trophozoites and cysts and also that these antibodies are directed to several antigenic determinants.