3D fractals as SERS active platforms: Preparation and evaluation for gas phase detection of G-nerve agents

One of the main limitations of the technique surface-enhanced Raman scattering (SERS) for chemical detection relies on the homogeneity, reproducibility and reusability of the substrates. In this work, SERS active platforms based on 3D-fractal microstructures is developed by combining corner lithography and anisotropic wet etching of silicon, to extend the SERS-active area into 3D, with electrostatically driven Au@citrate nanoparticles (NPs) assembly, to ensure homogeneous coating of SERS active NPs over the entire microstructured platforms. Strong SERS intensities are achieved using 3D-fractal structures compared to 2D-planar structures; leading to SERS enhancement factors for R6G superior than those merely predicted by the enlarged area effect. The SERS performance of Au monolayer-over-mirror configuration is demonstrated for the label-free real-time gas phase detection of 1.2 ppmV of dimethyl methylphosphonate (DMMP), a common surrogate of G-nerve agents. Thanks to the hot spot accumulation on the corners and tips of the 3D-fractal microstructures, the main vibrational modes of DMMP are clearly identified underlying the spectral selectivity of the SERS technique. The Raman acquisition conditions for SERS detection in gas phase have to be carefully chosen to avoid photo-thermal effects on the irradiated area

Calcificación parabicipital atípica en un cachorro de Terranova : caso clínico

Se describe un caso atípico de calcificación paratendinosa en la región de inserción del músculo bicipital en un Terranova macho de 1 año de edad. El diagnóstico del proceso se realizó mediante la historia clínica, y el estudio radiológico y tomográfico de la región del hombro. La masa calcificada se extrajo quirúrgicamente y la evolución postoperatoria fue excelente

Highly sensitive SERS quantification of organophosphorous chemical warfare agents: A major step towards the real time sensing in the gas phase

A surface-enhanced Raman scattering (SERS)-based sensor was developed for the label-free real-time gas phase detection of dimethyl methylphosphonate (DMMP); a surrogate molecule of the G-series nerve agents which are of particular concern due to its extreme toxicity, persistence and previous deployment. The SERS platform was designed using simple elements (Au nano-particles) coated with a citrate layer, and a self-assembly procedure that yields near- optimum distances among the nanoparticles. The citrate coating acts as an effective trap of the target molecules on the immediate vicinity of the Au nanoparticle surface under ambient conditions by reversible hydrogen bonding type interactions. For the first time, we have been able to detect sub-ppm concentrations of DMMP in gas phase (130 parts-per-billion), as might be found on potential emergency scenarios. The high sensitivity, simple preparation and reusability of the SERS platforms developed in this work open up the way for immediate detection of chemical warfare agents in realistic scenarios

New insights into the genetic etiology of Alzheimer's disease and related dementias

Characterization of the genetic landscape of Alzheimer's disease (AD) and related dementias (ADD) provides a unique opportunity for a better understanding of the associated pathophysiological processes. We performed a two-stage genome-wide association study totaling 111,326 clinically diagnosed/'proxy' AD cases and 677,663 controls. We found 75 risk loci, of which 42 were new at the time of analysis. Pathway enrichment analyses confirmed the involvement of amyloid/tau pathways and highlighted microglia implication. Gene prioritization in the new loci identified 31 genes that were suggestive of new genetically associated processes, including the tumor necrosis factor alpha pathway through the linear ubiquitin chain assembly complex. We also built a new genetic risk score associated with the risk of future AD/dementia or progression from mild cognitive impairment to AD/dementia. The improvement in prediction led to a 1.6- to 1.9-fold increase in AD risk from the lowest to the highest decile, in addition to effects of age and the APOE ε4 allele

Multiancestry analysis of the HLA locus in Alzheimer’s and Parkinson’s diseases uncovers a shared adaptive immune response mediated by HLA-DRB1*04 subtypes

Across multiancestry groups, we analyzed Human Leukocyte Antigen (HLA) associations in over 176,000 individuals with Parkinson’s disease (PD) and Alzheimer’s disease (AD) versus controls. We demonstrate that the two diseases share the same protective association at the HLA locus. HLA-specific fine-mapping showed that hierarchical protective effects of HLA-DRB1*04 subtypes best accounted for the association, strongest with HLA-DRB1*04:04 and HLA-DRB1*04:07, and intermediary with HLA-DRB1*04:01 and HLA-DRB1*04:03. The same signal was associated with decreased neurofibrillary tangles in postmortem brains and was associated with reduced tau levels in cerebrospinal fluid and to a lower extent with increased Aβ42. Protective HLA-DRB1*04 subtypes strongly bound the aggregation-prone tau PHF6 sequence, however only when acetylated at a lysine (K311), a common posttranslational modification central to tau aggregation. An HLA-DRB1*04-mediated adaptive immune response decreases PD and AD risks, potentially by acting against tau, offering the possibility of therapeutic avenues

Engineering plasmonic nanostructures for label-free SERS detection of neurotoxic gases

In this work, we explore the SERS based sensing capabilities of core-shell nanostructures for gas detection of neurotoxic agents at ppm level. These nanostructures generate intense localized surface plasmon resonances which are engineered by tuning geometrical parameters, in particular the aspect ratio of the metallic nanorods and the thickness of the silica mesoporous shell to extend the spectral window for the SERS based sensing from the visible to the near-infrared. This nanoarchitecture enables the integration of sampling preconcentration and detection of Sarin gas surrogate in a single SERS uni

Formación de conceptos : estrategias y niveles de asimilación de la realidad circundante al finalizar el Preescolar (5 años)

Desde el modelo piagetiano, se pretende medir los modelos o estrategias utilizados por los niños para conceptualizar, lo que incluye el análisis de tres aspectos: la naturaleza de los atributos utilizados preferentemente por los niños, si son, y en que medida, figurales (descripción externa) o no figurales (funcionales); y la relación de ambas categorías con las diferentes áreas de la experiencia infantil. La amplitud o dominio del campo semántico alcanzado por el niño de los conceptos que elabora. Los puntos de referencia o atributos más frecuentes elegidos por los niños para formar sus conceptos. 25 centros escolares con 244 casos, estratificados según sexo, tipo de enseñanza y medio sociológico. Partiendo de la hipótesis de que el proceso de conceptualización es una variable dependiente de los diferentes ámbitos en los que el niño vive sus experiencias, consideran tres ámbitos: experiencias corporales, natural y social; reduciendo el campo al estudio de tres conceptos: mano, lluvia, colegio. Utilizan técnicas gráficas, representación gráfica por parte del niño de los tres conceptos; y entrevista personal, con base a los propios dibujos del niño y en los modelos presentados por el investigador. Hay un 35 por ciento más de sujetos pertenecientes al subgrupo urbano que aluden a atributos funcionales en la prueba gráfica y totalmente espontánea, respecto a los otros dos subgrupos (rural y semiurbano), siendo, dicho grupo, el que más ampliamente domina los tres conceptos estudiados (mano, lluvia, colegio) a nivel de figural. Estos datos ponen de manifiesto el influjo del factor aprendizaje. El grupo urbano se manifiesta más evolucionado. El nivel alcanzado por el proceso conceptualizador depende de la amplitud con que se ha realizado el nivel inferior; así se alcanza el nivel funcional en la medida en que se manifiesta mayor riqueza en la asimilación figural.AragónBiblioteca de Educación del Ministerio de Educación, Cultura y Deporte; Calle San Agustín, 5 - 3 Planta; 28014 Madrid; Tel. +34917748000; Fax +34917748026; [email protected]