2,156 research outputs found

    Modification of the optical response of alpha quartz via the deposition of gold nanoparticles in etched ion tracks

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    ”This study addresses the experimental methods used to develop and characterize plasmonic devices capable of modifying the optical response of alpha quartz via the deposition of gold nanoparticles in etched ion tracks. In the first part of the research, the microstructural characterization of latent and etched ion tracks produced in alpha quartz (α-SiO2) is presented. Single crystals of α-SiO2 were irradiated with two highly energetic ions to different nominal fluences. As expected, the morphology of the resulting ion tracks depends on the energy of the incident ion and their stopping powers within the target material. Subsequent chemical vapor-etching was conducted to create nanowells in the crystal structure. The etching process resulted in facetted nanowells, whose superficial dimensions increased with etching times and etchant concentrations. It was found that the etching rate is highly dependent on crystal orientation. Additionally, Raman spectroscopic analysis of the phonon confinement effect and strain due to the ion tracks is presented. Results show that the optical phonon modes undergo a shift towards higher frequencies while broadening asymmetrically compared to the unirradiated samples due to phonon confinement effects. In the second part of the research, the deposition of gold nanoparticles inside of the nanowells was conducted. The modification of the optical response of quartz by depositing gold nanoparticles in the nanowells is discussed. An increase in the Raman intensity was observed thanks to the enhancement of the electromagnetic field produced by localized surface plasmons at the surface of the gold nanoparticles. The deposition of nanoparticles in etched ion tracks in fused silica was also achieved and is also briefly discussed”--Abstract, page iv

    Reinforcement of the Plasmon–phonon Coupling in Α-Quartz Via Deposition of Gold Nanoparticles in Etched Ion Tracks

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    This study reports a large reinforcement of the plasmon–phonon coupling in alpha quartz achieved through the controlled deposition of gold nanoparticles into nano templates produced through chemical etching of ion tracks. Preferential agglomeration of nanoparticles within the etched ion tracks (nano wells) was observed in Scanning Electron Microscopy and Atomic Force Microscopy images. Raman characterization of quartz substrates with different nanoparticle concentrations revealed a relationship between the plasmon–phonon coupling intensity and nanoparticle concentration. Reinforcement of the plasmon–phonon coupling was observed as an increase in the Raman intensity with increasing concentration of deposited nanoparticles. The intensity initially increased linearly with nanoparticle concentration up to about 4 x 106 nps/”L where a saturation regime was identified. In the saturation regime, a roughly 200-fold increase in the scattering intensity was measured in the first micron of the specimen. At higher nanoparticle concentrations, the Raman intensity decreased exponentially following the Beer–Lambert Law. The reduction in the Raman intensity is attributed to increased laser absorption with increasing nanoparticle layer thickness. Comparatively weak reinforcement of Raman scattering was observed when nanoparticles were deposited on unirradiated and unetched samples, suggesting that the reinforcement of plasmon–phonon coupling may be favored by the anisotropic geometry of the nano wells. In particular, the etched tracks promote nanoparticles agglomeration likely promoting the formation of plasmon hotspots

    Non-linear classifiers applied to EEG analysis for epilepsy seizure detection

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    This work presents a novel approach for automatic epilepsy seizure detection based on EEG analysis that exploits the underlying non-linear nature of EEG data. In this paper, two main contributions are presented and validated: the use of non-linear classifiers through the so-called kernel trick and the proposal of a Bag-of-Words model for extracting a non-linear feature representation of the input data in an unsupervised manner. The performance of the resulting system is validated with public datasets, previously processed to remove artifacts or external disturbances, but also with private datasets recorded under realistic and non-ideal operating conditions. The use of public datasets caters for comparison purposes whereas the private one shows the performance of the system under realistic circumstances of noise, artifacts, and signals of different amplitudes. Moreover, the proposed solution has been compared to state-of-the-art works not only for pre-processed and public datasets but also with the private datasets. The mean F1-measure shows a 10% improvement over the second-best ranked method including cross-dataset experiments. The obtained results prove the robustness of the proposed solution to more realistic and variable conditions. (C) 2017 Elsevier Ltd. All rights reserved

    Effects of mindfulness-based interventions on biomarkers in healthy and cancer populations: a systematic review

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    Background: Only a small number of articles have investigated the relationship between mindfulness-based interventions (MBIs) and biomarkers. The aim of this systematic review was to study the effect of MBIs on specific biomarkers (cytokines, neuropeptides and C-reactive protein (CRP)) in both healthy subjects and cancer patients. Methods: A search was conducted using PubMed, EMBASE, PsycINFO and the Cochrane library between 1980 and September 2016. Results: A total of 13 studies with 1110 participants were included. In the healthy population, MBIs had no effect on cytokines, but were found to increase the levels of the neuropeptide insulin-like growth factor 1 (IGF-1). With respect to neuropeptide Y, despite the absence of post-intervention differences, MBIs may enhance recovery from stress. With regard to CRP, MBIs could be effective in lower Body Mass Index (BMI) individuals. In cancer patients, MBIs seem to have some effect on cytokine levels, although it was not possible to determine which specific cytokines were affected. One possibility is that MBIs might aid recovery of the immune system, increasing the production of interleukin (IL)-4 and decreasing interferon gamma (IFN-gamma). Conclusions: MBIs may be involved in changes from a depressive/carcinogenic profile to a more normalized one. However, given the complexity and different contexts of the immune system, and the fact that this investigation is still in its preliminary stage, additional randomized controlled trials are needed to further establish the impact of MBI programmes on biomarkers in both clinical and non-clinical populations.Instituto de Salud Carlos III of the Spanish Ministry of Economy and CompetitivenessNetwork for Prevention and Health Promotion in primary Care from the Instituto de Salud Carlos III of the Ministry of Economy and Competitiveness (Spain)European Union ERDF fundsAragon Hlth Sci Inst IACS, Zaragoza, SpainShowa Univ, Dept Psychiat, Sch Med, Tokyo, JapanPrimary Care Prevent & Hlth Promot Res Network RE, Barcelona, SpainUniv Zaragoza, Miguel Servet Univ Hosp, Dept Psychiat, Zaragoza, SpainUniv Zaragoza, Fac Social & Human Sci, Dept Psychol & Sociol, Teruel, SpainFed Univ Sao Paulo UNIFESP, Dept Prevent Med, Mente Aberta Brazilian Ctr Mindfulness & Hlth Pro, Sao Paulo, BrazilHosp Israelita Albert Einstein, Sao Paulo, BrazilUniv Zaragoza, Fac Hlth Sci & Sports, Huesca, SpainUniv Balearic Isl, Res Inst Hlth Sci IUNICS, Palma De Mallorca, SpainFed Univ Sao Paulo UNIFESP, Dept Prevent Med, Mente Aberta Brazilian Ctr Mindfulness & Hlth Pro, Sao Paulo, BrazilInstituto de Salud Carlos III of the Spanish Ministry of Economy and Competitiveness: PI13/01637Network for Prevention and Health Promotion in primary Care from the Instituto de Salud Carlos III of the Ministry of Economy and Competitiveness (Spain): RD12/0005Web of Scienc

    Process evaluation of the health education resource Abre los Ojos for street-involved youth in MedellĂ­n

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    ABSTRACT: Conduct a process evaluation of a health education resource (pamphlet)ž Abre los Ojos, designed for street-involved youth in MedellĂ­n. The primary foci of the evaluation were the process of developing the resource and youth’s subsequent perception of the resource. Methodology: Drawing upon both qualitative and quantitative data, a process evaluation was undertaken. Ninety four street-involved youth between the ages of 14–24 years completed surveys about the resource. These semi-structured interviews were key for the information about youth perception of the resource. In addition to individual interviews, prior to resource creation, a series of focus groups were integral for the development of the resource. Results: The process of consulting with the target population through the focus groups was effective in obtaining their ideas and feedback about what type of content they would like to see in a health education resource, and how they wanted that content presented. After distribution, participants described that Abre los Ojos contained information that was valuable and relevant to their experiences. While not a primary focus of this evaluation, the individual interviews were also able to provide some preliminary insight into whether Abre los Ojos was an effective means for participants to increase their knowledge of content included in the resource. Conclusion: The collaborative process of jointly developing the resource content in partnership with the youth proved very worthwhile. While our research team chose to include information about HIV, through focus group dialogue, the youth themselves determined the additional content themes (piercings, use of solvents, and description of life on the street). The resulting resource was well-received by members of the street-involved population who had not been involved in its design.RESUMEN: Evaluar el proceso de desarrollo del folleto educativo en salud Abre los ojos, diseñado para jĂłvenes en situaciĂłn de calle en MedellĂ­n. Se evaluaron tanto el proceso de su creaciĂłn como su percepciĂłn posterior entre los jĂłvenes. MetodologĂ­a: la evaluaciĂłn incluyĂł el anĂĄlisis de datos cuantitativos y cualitativos mediante entrevistas individuales y grupos focales con jĂłvenes en situaciĂłn de calle de MedellĂ­n. De estos jĂłvenes, 94, con edades entre 14 y 24 años, respondieron una encuesta de percepciones sobre el material. Resultados: los grupos focales fueron efectivos para recoger las ideas y sugerencias del tipo de contenido que ellos querĂ­an para el material educativo de salud y la forma de presentarlo. DespuĂ©s de distribuirlo, la respuesta general resultĂł positiva. Manifestaron que contenĂ­a informaciĂłn valiosa y relevante en relaciĂłn con sus experiencias. Pese a no ser el objeto principal de esta evaluaciĂłn, las entrevistas individuales proporcionaron resultados preliminares acerca de la posible efectividad del material educativo para incrementar el nivel de conocimiento de los participantes sobre los temas allĂ­ incluidos. ConclusiĂłn: el proceso colaborativo para desarrollar el contenido del material educativo, en asocio con los jĂłvenes, probĂł ser muy valioso. Mientras que los investigadores seleccionaron informaciĂłn sobre vih, los jĂłvenes seleccionaron informaciĂłn de otros temas como piercing, uso de solventes y lo que significa vivir en la calle. El material educativo resultante fue bien recibido por representantes de los jĂłvenes en situaciĂłn de calle de MedellĂ­n, diferentes a los que participaron en su diseño

    Low NKp30, NKp46 and NKG2D expression and reduced cytotoxic activity on NK cells in cervical cancer and precursor lesions

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    <p>Abstract</p> <p>Background</p> <p>Persistent high risk HPV infection can lead to cervical cancer, the second most common malignant tumor in women worldwide. NK cells play a crucial role against tumors and virus-infected cells through a fine balance between activating and inhibitory receptors. Expression of triggering receptors NKp30, NKp44, NKp46 and NKG2D on NK cells correlates with cytolytic activity against tumor cells, but these receptors have not been studied in cervical cancer and precursor lesions. The aim of the present work was to study NKp30, NKp46, NKG2D, NKp80 and 2B4 expression in NK cells from patients with cervical cancer and precursor lesions, in the context of HPV infection.</p> <p>Methods</p> <p>NKp30, NKp46, NKG2D, NKp80 and 2B4 expression was analyzed by flow cytometry on NK cells from 59 patients with cervical cancer and squamous intraepithelial lesions. NK cell cytotoxicity was evaluated in a 4 hour CFSE/7-AAD flow cytometry assay. HPV types were identified by PCR assays.</p> <p>Results</p> <p>We report here for the first time that NK cell-activating receptors NKp30 and NKp46 are significantly down-regulated in cervical cancer and high grade squamous intraepithelial lesion (HGSIL) patients. NCRs down-regulation correlated with low cytolytic activity, HPV-16 infection and clinical stage. NKG2D was also down-regulated in cervical cancer patients.</p> <p>Conclusion</p> <p>Our results suggest that NKp30, NKp46 and NKG2D down-regulation represent an evasion mechanism associated to low NK cell activity, HPV-16 infection and cervical cancer progression.</p

    Overexpression. of dehydrin tas14 gene improves the osmotic stress imposed by drought and salinity in tomato

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    [EN] One strategy to increase the level of drought and salinity tolerance is the transfer of genes codifying different types of proteins functionally related to macromolecules protection, such as group 2 of late embryogenesis abundant (LEA) proteins or dehydrins. The TAS14 dehydrin was isolated and characterized in tomato and its expression was induced by osmotic stress (NaCl and mannitol) and abscisic acid (ABA) [Godoy et al., Plant Mol Biol 1994;26:1921-1934], yet its function in drought and salinity tolerance of tomato remains elusive. In this study, transgenic tomato plants overexpressing tas14 gene under the control of the 35SCaMV promoter were generated to assess the function of tas14 gene in drought and salinity tolerance. The plants overexpressing tas14 gene achieved improved long-term drought and salinity tolerance without affecting plant growth under non-stress conditions. A mechanism of osmotic stress tolerance via osmotic potential reduction and solutes accumulation, such as sugars and K+ is operating in tas14 overexpressing plants in drought conditions. A similar mechanism of osmotic stress tolerance was observed under salinity. Moreover, the overexpression of tas14 gene increased Na+ accumulation only in adult leaves, whereas in young leaves, the accumulated solutes were K+ and sugars, suggesting that plants overexpressing tas14 gene are able to distribute the Na+ accumulation between young and adult leaves over a prolonged period in stressful conditions. Measurement of ABA showed that the action mechanism of tas14 gene is associated with an earlier and greater accumulation of ABA in leaves during short-term periods. A good feature for the application of this gene in improving drought and salt stress tolerance is the fact that its constitutive expression does not affect plant growth under non-stress conditions, and tolerance induced by overexpression of tas14 gene was observed at the different stress degrees applied to the long term. (C) 2011 Elsevier GmbH. All rights reserved.This work was supported by the Spanish Ministry of Science and Innovation through grant AGL2009-13388-C03 and by the Council of Science and Technology from the Region of Murcia (Spain) (Fundacion SENECA) through grant 04553/GERM/06.Muñoz Mayor, A.; Pineda Chaza, BJ.; García Abellån, JO.; Antón Martínez, MT.; García Sogo, B.; Sånchez Bel, P.; Flores, FB.... (2012). Overexpression. of dehydrin tas14 gene improves the osmotic stress imposed by drought and salinity in tomato. Journal of Plant Physiology. 169(5):459-468. https://doi.org/10.1016/j.jplph.2011.11.018S459468169

    Non-productive angiogenesis disassembles Aß plaque-associated blood vessels

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    The human Alzheimer’s disease (AD) brain accumulates angiogenic markers but paradoxically, the cerebral microvasculature is reduced around Aß plaques. Here we demonstrate that angiogenesis is started near Aß plaques in both AD mouse models and human AD samples. However, endothelial cells express the molecular signature of non-productive angiogenesis (NPA) and accumulate, around Aß plaques, a tip cell marker and IB4 reactive vascular anomalies with reduced NOTCH activity. Notably, NPA induction by endothelial loss of presenilin, whose mutations cause familial AD and which activity has been shown to decrease with age, produced a similar vascular phenotype in the absence of Aß pathology. We also show that Aß plaque-associated NPA locally disassembles blood vessels, leaving behind vascular scars, and that microglial phagocytosis contributes to the local loss of endothelial cells. These results define the role of NPA and microglia in local blood vessel disassembly and highlight the vascular component of presenilin loss of function in AD

    Search for chargino-neutralino production with mass splittings near the electroweak scale in three-lepton final states in √s=13 TeV pp collisions with the ATLAS detector

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    A search for supersymmetry through the pair production of electroweakinos with mass splittings near the electroweak scale and decaying via on-shell W and Z bosons is presented for a three-lepton final state. The analyzed proton-proton collision data taken at a center-of-mass energy of √s=13  TeV were collected between 2015 and 2018 by the ATLAS experiment at the Large Hadron Collider, corresponding to an integrated luminosity of 139  fb−1. A search, emulating the recursive jigsaw reconstruction technique with easily reproducible laboratory-frame variables, is performed. The two excesses observed in the 2015–2016 data recursive jigsaw analysis in the low-mass three-lepton phase space are reproduced. Results with the full data set are in agreement with the Standard Model expectations. They are interpreted to set exclusion limits at the 95% confidence level on simplified models of chargino-neutralino pair production for masses up to 345 GeV
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