El Grup de Concurrència i Temps Real col·labora amb la branca d'estudiants de l'IEEE

Peer Reviewe

Geometrical locus of massive test particle orbits in the space of physical parameters in Kerr space-time

Gravitational radiation of binary systems can be studied by using the adiabatic approximation in General Relativity. In this approach a small astrophysical object follows a trajectory consisting of a chained series of bounded geodesics (orbits) in the outer region of a Kerr Black Hole, representing the space time created by a bigger object. In our paper we study the entire class of orbits, both of constant radius (spherical orbits), as well as non-null eccentricity orbits, showing a number of properties on the physical parameters and trajectories. The main result is the determination of the geometrical locus of all the orbits in the space of physical parameters in Kerr space-time. This becomes a powerful tool to know if different orbits can be connected by a continuous change of their physical parameters. A discussion on the influence of different values of the angular momentum of the hole is given. Main results have been obtained by analytical methods.Comment: 26 pages, 12 figure

Novel methods and devices to enhance transdermal drug delivery: The importance of laser radiation in transdermal drug delivery

Skin permeation-enhancement technology is a rapidly developing field, which could significantly increase the number of drugs suitable for transdermal delivery. In this review, we highlight recent advances in both 'passive and 'active transdermal drug-delivery technologies, as well as in the laser ablation method. This paper concludes with a brief forward-looking perspective discussing what can be expected as laser technology continues to develop in the coming years.Peer Reviewe

Cooperative effect of 5-aminolevulinic acid and gold nanoparticles for photodynamic therapy of cancer

An enhanced capacity for protoporphyrin IX (PpIX) synthesis through 5- aminolevulinic acid (ALA) administration has been reported in cancer cells. We compared the effect of ALA and ALA combined with gold nanoparticles (ALA–AuNPs) for photodynamic ther- apy (PDT) on human cervical cancer cell line. Because PpIX after photoactivation produces reactive oxygen species (ROS), ALA–AuNPs combinations can enhance this production and then induce higher phototoxicity. With this aim, two different-sized AuNPs (14 and 136 nm, AuNP1 and AuNP2, respectively) were successfully synthesized and characterized by UV–visi- ble spectrophotometry and transmission electron microscopy. AuNPs were combined with ALA to evaluate their cooperative action in the intracellular ROS production, cell viability, and cell death mechanism. Results showed that ALA–AuNPs combinations induced cell death via ROS- mediated apoptosis after PDT. When exposed to light at their resonance wavelength, AuNP2 combined with ALA result in cytotoxicity and cell injury in greater extension than ALA and ALA–AuNP1 combinationPeer Reviewe

In vitro transdermal and biological evaluation of ALA-loaded poly(N-isopropylacrylamide) and poly(N-isopropylacrylamide-co-acrylic acid) microgels for photodynamic therapy.

Peer Reviewe

Use of poly(N‐isopropylacrylamide) nanohydrogels for the controlled release of pimaricin in active packaging

We propose here a delivery drug‐polymer system using poly(N‐isopropylacrylamide) (PNIPA) nanohydrogels that enables pimaricin to be protected from hostile environments and allows the controlled release of the antifungal through environmental stimuli. We synthesized 2 nanohydrogels, 1 with 100% N‐isopropylacrylamide (PNIPA(5)) and 1 with 80% N‐isopropylacrylamide copolymerized and 20% acrylic acid (PNIPA‐20AA(5)). Both were then, loaded with a pimaricin aqueous solution. The pimaricin release profiles of these 2 nanohydrogels were considerably different: PNIPA(5) released 10% and PNIPA‐20AA(5) released 30% with respect to the free pimaricin release. Moreover, the diffusion experiments showed that pimaricin was released from the PNIPA‐20AA(5) nanohydrogel for up to 3 times longer than free pimaricin. Therefore, incorporating acrylic acid as comonomer into the PNIPA nanohydrogel resulted in a slower but more continuous release of pimaricin. The highest pimaricin levels were reached when the most hydrophilic nanohydrogel was used. The bioassay results showed that the pimaricin‐nanohydrogel system was highly effective in inhibiting the growth of the indicator strain in conditions of thermal abuse. The spoilage in acidified samples stored under fluorescent lighting was reduced by 80.94%± 33.02% in samples treated with a pimaricin‐loaded nanohydrogel, but only by 19.91%± 6.68% in samples treated with free pimaricin. Therefore, 2 conclusions emerge from this study. One is that the nanohydrogel delivery system could impede the degradation of pimaricin. The other is that the inhibitory effect of the antifungal on yeast growth is more pronounced when it is added included into the nanohydrogel to the food, especially in an acidic environment. Practical Application:  This article presents relevant results on the use of nanohydrogels in food packaging. Nanohydrogels could provide protection so that the pimaricin remains active for a longer time. They also allow the controlled release of pimaricin, which thus regulates the unnecessary presence of the antifungal in the food.Ministerio de Educación y Ciencia | Ref. MAT2006-11662-C03-01Ministerio de Educación y Ciencia | Ref. MAT2006-11662-C03-02Ministerio de Educación y Ciencia | Ref. MAT2006-11662-C03-03Ministerio de Ciencia e Innovación | Ref. MAT2010-21509-C03-01Ministerio de Ciencia e Innovación | Ref. /EUI 2008-00115Universidade de Vig