Design and study of a photo-switchable polymeric system in the presence of ZnS nanoparticles under the influence of UV light irradiation

Recent progress in the field of photosensitive materials has prompted a need to develop efficient methods to synthesize materials with basic intermolecular architectural designs and novel properties. Accordingly, in this work we design and study a photoactive polymer as a photo-switchable polymeric system in the presence and absence of ZnS nanoparticles (average size < 10 nm) at 5 wt.%. The influence of UV light irradiation on its properties were also studied. The photoactive block copolymer was obtained from styrene (S) and methyl methacrylate (MMA) as monomers and 1-(2-hydroxyethyl)-3,3-dimethylindoline-6-nitrobenzopyran (SP) was grafted to the block copolymer backbone as a photochromic agent. Furthermore, the incorporation of ZnS (NPs) as photo-optical switch component into the system enhances the purple colored photo-emission, with the open form of the spiropyran derivative (merocyanine, MC). The ZnS stabilize the isomeric equilibrium in the MC interconversion of the photochromic agent. The photo-switchable properties of the PS-b-PMMA-SP in the presence of ZnS (NPs) were examined using UV-VIS spectroscopy, Photoluminescence (PL) spectroscopy, optical fluorescence and scanning electronic microscopy (SEM-EDX.). The observed changes in the absorbance, fluorescence and morphology of the system were associated to the reversible interconversion of the two states of the photochromic agent which regulates the radiative deactivation of the luminescent ZnS NPs component. After UV irradiation the photoactive polymer becomes purple in color. Therefore, these basic studies can lead to the development of innovative functional and nanostructured materials with photosensitive character as photosensitive molecular switches

Porous Surface Films With Tunable Morphologies and Hydrophobic Properties Based on Block Copolymer Under the Effects of Thermal Annealing

The fabrication of porous-structured polymer films with patterned surface structures has recently attracted increased interest within the material science field. In this work, a series of microstructure scale patterned polymer films were obtained via breath figure methods (BF) with hydrophobic surface films based on self-assembled diblock copolymers by atom-transfer radical polymerization (ATRP). The surface characteristics and morphological properties, pore size, roughness, thickness, and wettability of the block copolymer films was studied in response to variation of the hydrophilic co-monomer structures. A significant improvement of the quality and order of the hydrophobic films was observed in response to thermal annealing and a consequent optimization of the assembly process

Creutzfeldt-Jakob disease:recent developments

Creutzfeldt-Jakob disease (CJD) is a rare prion disorder that has been the subject of both professional and public interest following the identification of variant CJD as a zoonotic disorder. There have been recent advances in diagnostic techniques, including real-time quaking-induced conversion and magnetic resonance imaging brain scan, that have allowed more accurate case recognition in all forms of CJD. Although the epidemic of variant CJD is clearly in decline, prevalence studies suggest that it may be premature to be complacent about concerns for public health

Protective Ag :TiO2 thin films for pressure sensors in orthopedic prosthesis: the importance of composition, structural and morphological features on the biological response of the coatings

DC reactive magnetron sputtered Ag:TiO2 nanocomposite thin films were developed to be used as protective coatings in pressure sensor devices. The coatings, with Ag content varying from 0 to about 30 at.%, were prepared and characterized in order to study their biological response. The as-deposited samples were annealed in vacuum at 500 °C in order to evaluate the influence of their morphological and structural differences over the response elicited upon contact with simulated bodily fluids and cultured human cells, as well as selected microorganisms. The results showed that the annealing treatment produced less porous films with an enhanced structure, with a significant reduction in structural defects and improved crystallinity. Additionally, samples with higher Ag contents (≥12.8 at.%) exhibited Ag agglomerates/clusters at the surface, a result anticipated from the XRD data. The crystallization of the TiO2 matrix was also observed by XRD analysis, albeit delayed by the dispersion of Ag into the matrix. Biological characterization showed that the antimicrobial activity and cytotoxicity of the coatings were directly related with their composition, closely followed by the particular structural and morphological features, namely those resulting from annealing process.This research is partially sponsored by FEDER funds through the program COMPETE—Programa Operacional Factores de Competitividade and by national funds through FCT—Fundação para a Ciência e a Tecnologia, under the projects PEst-C/EME/UI0285/2011, PTDC/SAU-ENB/116850/2010, PTDC/CTM-NAN/112574/2009P. T Matamá acknowledges FCT for Grant SFRH/BPD/47555/2008

2-Deoxy-D-Glucose Treatment of Endothelial Cells Induces Autophagy by Reactive Oxygen Species-Mediated Activation of the AMP-Activated Protein Kinase

Autophagy is a cellular self-digestion process activated in response to stresses such as energy deprivation and oxidative stress. However, the mechanisms by which energy deprivation and oxidative stress trigger autophagy remain undefined. Here, we report that activation of AMP-activated protein kinase (AMPK) by mitochondria-derived reactive oxygen species (ROS) is required for autophagy in cultured endothelial cells. AMPK activity, ROS levels, and the markers of autophagy were monitored in confluent bovine aortic endothelial cells (BAEC) treated with the glycolysis blocker 2-deoxy-D-glucose (2-DG). Treatment of BAEC with 2-DG (5 mM) for 24 hours or with low concentrations of H2O2 (100 µM) induced autophagy, including increased conversion of microtubule-associated protein light chain 3 (LC3)-I to LC3-II, accumulation of GFP-tagged LC3 positive intracellular vacuoles, and increased fusion of autophagosomes with lysosomes. 2-DG-treatment also induced AMPK phosphorylation, which was blocked by either co-administration of two potent anti-oxidants (Tempol and N-Acetyl-L-cysteine) or overexpression of superoxide dismutase 1 or catalase in BAEC. Further, 2-DG-induced autophagy in BAEC was blocked by overexpressing catalase or siRNA-mediated knockdown of AMPK. Finally, pretreatment of BAEC with 2-DG increased endothelial cell viability after exposure to hypoxic stress. Thus, AMPK is required for ROS-triggered autophagy in endothelial cells, which increases endothelial cell survival in response to cell stress

Informe Programas de Seguimiento en España: Especies Marinas Amenazadas

DISPONIBLE PRÓXIMAMENTEEste informe tiene como objetivo identificar por primera vez el grado de implementación y la tipología de los programas de seguimiento presentes en las costas españolas. Para ello, se han analizado los programas de seguimiento puestos en marcha por las comunidades autónomas de España mediante una exhaustiva revisión bibliográfica y un proceso de consulta con los administradores de los servicios responsables de la gestión de la biodiversidad correspondientes. El análisis se realizó sobre una selección de 255 especies (78% del total). Este conjunto incluye diversos grupos taxonómicos y consideramos que su análisis ofrece una imagen representativa del grado de implementación y tipología de los programas de seguimiento en las costas españolas. Los resultados obtenidos muestran que, de esas 255 especies amenazadas de España, sólo 76 cuentan con algún tipo de seguimiento en alguna comunidad autónoma, lo que constituye solo un 29,8% del total de especies analizadas. Por otra parte, si consideramos los programas de seguimiento a nivel de cada comunidad autónoma donde están presentes las especies amenazadas, los resultados muestran que de los 1837 programas de seguimiento que deberían haber sido implementados en España, solamente se realizan 214, lo que representa sólo un 11,6%. Ante la evidente falta de programas de seguimiento, este informe analiza también el potencial de aportar información sobre la distribución y estado de las poblaciones de las especies amenazadas en dos de las principales plataformas de ciencia ciudadana marina en España: Observadores del Mar y RedPROMAR. Hasta la fecha del presente análisis, las plataformas Observadores del Mar y RedPROMAR han reportado información sobre 66 y 104 especies respectivamente, lo que representa un 40,7% y un 60,8% de las especies amenazadas potencialmente reportables por cada plataforma. En conclusión, el grado de implementación de los programas de seguimiento de especies amenazadas en España es deficiente. Durante la realización de este informe se ha puesto claramente de manifiesto la falta de un sistema de comunicación dedicado al reporte de la información, en concreto, sobre los programas de seguimiento de las especies incluidas en el marco de los diferentes Convenios nacionales e internacionales. Ante esta falta de información, es urgente dar un impulso decidido a la implementación de programas de seguimiento en las diferentes comunidades autónomas, reforzando aquellos existentes e iniciando aquellos que faltan. Igualmente, se recomienda desarrollar un sistema de reporte de información de los seguimientos (u optimizar los existentes). También se recomienda incluir las iniciativas de ciencia ciudadana marina como Observadores del Mar y RedPROMAR para contribuir de forma complementaria a los programas de seguimiento. La adopción de estas recomendaciones permitirá evaluar de forma más eficaz el estado de conservación de las especies amenazadas en España y poder adptar medidas más efectivas.Peer reviewe