136 research outputs found

    Domain configuration and magnetization switching in arrays of permalloy nanostripes

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    The proximity effect in the collective behavior of arrays of magnetic nanostripes is currently a subject of intensive research. The imperative of reducing the size and distances between elements in order to achieve higher storage capacity, faster access to the information as well as low energy consumption, brings consequences about the isolated behavior of the elements and devices. Parallel to each other permalloy nanostripes with high aspect ratio have been prepared by the nanolithography technique. The evolution of the closure domains and the magnetization direction in individual nanostructures has been imaged under applied magnetic fields using Variable Field Magnetic Force Microscopy. Moreover, the magnetostatic interactions between neighboring elements and the proximity effects in arrays of such nanostructures have been quantitatively analyzed by Magnetic Force Microscopy and micromagnetic simulations. The agreement between simulations and the experimental results allows us to conclude the relevance of those interactions depending on the geometry characteristics. In particular, results suggest that the magnetostatic coupling between adjacent nanostripes vanishes for separation distances higher than 500 nm

    Determination of closure domain penetration in electrodeposited microtubes by combined magnetic force microscopy and giant magneto-impedance techniques

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    The domain structure of electrodeposited Co90P10 microtubes exhibiting radial magnetic anisotropy and giant magneto-impedance effect has been characterized by combined magnetic force microscopy imaging and impedance measurements. It has been shown that the size of the closure domains increases with the CoP layer thickness. Furthermore, the depth of the closure domains has been quantitatively determined from the high frequency behavior.The authors want to thank Professor J. Miltat for helpful discussions. This work has been performed under Project No. CAM/07N/0033/1998. A. Asenjo would like to thank the CAM (Spain) for the postdoctoral fellowship. J. P. Sinnecker thanks the Brazilian agencies CNPq and FAPERJ for the financial support.Peer reviewe

    3D plasmonic chiral colloids

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    3D plasmonic chiral colloids are synthesized through deterministically grouping of two gold nanorod AuNRs on DNA origami. These nanorod crosses exhibit strong circular dichroism (CD) at optical frequencies which can be engineered through position tuning of the rods on the origami. Our experimental results agree qualitatively well with theoretical predictions. © 2014 The Royal Society of Chemistry.Peer Reviewe

    Evaluación de una experiencia de ApS como Instrumento del Aprendizaje Interdisciplinar en el Grado de Enfermería

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    Realizar un servicio a la comunidad es uno de los métodos de aprendizaje más eficaces, porque los estudiantes encuentran el auténtico sentido a lo que estudian cuando aplican sus conocimientos y habilidades en una práctica solidaria, favoreciendo así el aprendizaje significativo, mejorando la propia motivación y los resultados académicos y promoviendo el desarrollo personal y social. A través de estrategias de aprendizaje-servicio (ApS) los docentes podemos estar más cerca de conseguir el verdadero éxito de la educación en la Universidad: abrir las aulas y vincular la adquisición de competencias interdisciplinares y transdiciplinares. Los resultados del presente estudio muestran que estudiantes valoran las actividades de ApS vinculadas a la promoción de la salud muy positivamente en relación con las expectativas, la autopercepción, el logro de los objetivos de aprendizaje y de servicio, el enfoque de la actividad, el logro de las competencias, el nivel de participación, su impacto y proyección social, así como su visión desde el campo profesional. ApS permite crear escenarios reales donde puedan desarrollarse todas las competencias, puesto que el mero conocimiento teórico no garantiza la formación de una ciudadanía participativa, solidaria, capaz de desarrollar proyectos individuales y colectivos

    Cadmium (Cd) and Lead (Pb) topsoil levels and incidence of childhood leukemias

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    There are few well-established risk factors for childhood leukemias. While the frequency of childhood leukemias might be partially attributable to some diseases (accounting for a small fraction of cases) or ionizing radiation, the role of heavy metals has not been assessed. The objective of our study was to assess the potential association between levels of cadmium (Cd) and lead (PB) in soil and childhood leukemias incidence. We conducted a population-based case-control study of childhood leukaemia in Spain, covering 2897 incident cases gathered from the Spanish Registry of Childhood Tumours and including 14 Spanish Regions with a total population of 5,307,433 children (period 1996-2015). Cd and Pb bioavailable levels at every children's home address were estimated using data from the Geochemical Atlas of Spain. We used logistic regression to estimate odds ratios (ORs) and their 95% confidence intervals (95%CIs); we included as covariates: sex, rurality, employment rate and socioeconomic status. Metal levels were analysed according to two definitions: as continuous variable assuming linearity and as categorical variables to explore a potentially nonlinear association (quantiles). Increases in both Cd and Pb topsoil levels were associated with increased probability of childhood leukemias incidence. The results for the models with the continuous variables showed that a unit increase on the topsoil level was associated with an OR of 1.11 for Cd (95%CI 1.00-1.24) and an OR of 1.10 for Pb (95%CI 0.99-1.21). Our study may point towards a possible link between residential Cd and Pb topsoil levels and the probability of childhood leukemias incidence. Residing in a location with the highest concentrations of these heavy metals compared to those locations with the lowest could increase the risk around a 20%, for both Cd and Pb.This work was supported by Carlos III Health Institute: FIS 12/01416, AESI PI16CIII/00009, AESI PI19CIII/00025.S

    Aislamiento de un extracto de BMP y estudio anatomopatológico del fenómeno de inducción ósea tras su implante en defectos óseos

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    El objetivo del presente trabajo fue determinar el potencial osteogénico de la proteína morfogenética ósea (BMP) en la reparación de grandes defectos diafisarios. Además, se investiga la acción coadyuvante de la fibronectina (FN). La BMP fue extraída a partir de hueso cortical bovino. Se utilizaron un total de 108 ratas Sprague Dawley. En cada animal, se resecó un segmento de diáfisis femoral de 1.5 cm, siendo inmovilizado el defecto óseo con una aguja en omega. Se rellenó el defecto implantando 25 mg de BMP con o sin 0.5 mg de FN en una cápsula de gelatina (36 animales en ambos grupos). Los resultados se compararon con los obtenidos en otro grupo (36 animales) en el que sólo se implantó FN que sirvió como grupo control. El proceso de reparación se evaluó mediante métodos histológicos y ultraestructurales. La aparición del fenómeno de inducción ósea con reconstrucción del defecto óseo fue mayor en el grupo con implante de BMP más FN (23 animales, 64%) que en el grupo en el que sólo se implantó BMP (20 animales, 56%). Ningún animal del grupo control manifestaba signos de inducción ósea.The aim of the present work was to evaluate the osteogenic potential of Bone Morphogenetic Protein (BMP) for reparation of large segmental bone defects. In addition, the coadjuvant efect of fibronectin (FN) was investigated. BMP was partially purified from bovine cortical bone. A total of 108 Sprague Dawley rats were used in the experiment. Diaphyseal segments of the femur (1.5 cm) were removed in each animal, manteinant the bone defect with a wire. A gelatine capsula containing 25 mg of BMP without or with 0.5 mg of FN, were implanted into the bone defect (36 animal in each group). Results were compared to those obtained in a control group (36 animals) in which FN alone was implanted. The bone repair process was assessed by histologic and ultrastructural methods. Bone induction with reconstruction of the defect was found more of ten in the group with both BMP and FN implanted (23 animals, 64%) than in the group with BMP implant alone (20 animals, 56%). Animals of the control group showed no bone induction. The results suggest that BMP augments the capacity of the host bed to sucessfully regenerate large segmental bone defects. FN seens to increase bone induction. This protein migth stabilize BMP locally improving contact between BMP and the surrounding cells

    TELMA: Entorno de formación personalizada online en Cirugía de Mínima Invasión

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    TELMA es un entorno de formación y aprendizaje online basado en edición de vídeo laparoscópico, la gestión del conocimiento y el trabajo colaborativo con el fin de mejorar la efectividad y eficacia de los procesos de formación (inicial y continuada) de los cirujanos de Cirugía de Mínima Invasión (CMI). TELMA explota el uso del vídeo laparoscópico como el núcleo de los contenidos didácticos y hace uso de tecnologías de formación online y gestión de contenidos digitales multimedia, para mejorar la adaptación, calidad y eficiencia del servicio ofrecido al usuario. TELMA persigue acortar las curvas de aprendizaje, proporcionando a los cirujanos un acceso ubicuo a contenidos educativos y metodologías didácticas, dotando al aprendizaje de mayor interactividad y proporcionando a los alumnos un papel más activo, una mejor adquisición de los conocimientos y habilidades y un mayor uso de las fuentes de información disponibles

    A comprehensive dataset of annotated brain metastasis MR images with clinical and radiomic data.

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    Brain metastasis (BM) is one of the main complications of many cancers, and the most frequent malignancy of the central nervous system. Imaging studies of BMs are routinely used for diagnosis of disease, treatment planning and follow-up. Artificial Intelligence (AI) has great potential to provide automated tools to assist in the management of disease. However, AI methods require large datasets for training and validation, and to date there have been just one publicly available imaging dataset of 156 BMs. This paper publishes 637 high-resolution imaging studies of 75 patients harboring 260 BM lesions, and their respective clinical data. It also includes semi-automatic segmentations of 593 BMs, including pre- and post-treatment T1-weighted cases, and a set of morphological and radiomic features for the cases segmented. This data-sharing initiative is expected to enable research into and performance evaluation of automatic BM detection, lesion segmentation, disease status evaluation and treatment planning methods for BMs, as well as the development and validation of predictive and prognostic tools with clinical applicability

    Tumour heterogeneity in glioblastoma assessed by MRI texture analysis: a potential marker of survival

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    Objective: The main objective of this retrospective work was the study of three-dimensional (3D) heterogeneity measures of post-contrast pre-operative MR images acquired with T1 weighted sequences of patients with glioblastoma (GBM) as predictors of clinical outcome. Methods: 79 patients from 3 hospitals were included in the study. 16 3D textural heterogeneity measures were computed including run-length matrix (RLM) features (regional heterogeneity) and co-occurrence matrix (CM) features (local heterogeneity). The significance of the results was studied using Kaplan?Meier curves and Cox proportional hazards analysis. Correlation between the variables of the study was assessed using the Spearman?s correlation coefficient. Results: Kaplan?Meyer survival analysis showed that 4 of the 11 RLM features and 4 of the 5 CM features considered were robust predictors of survival. The median survival differences in the most significant cases were of over 6 months. Conclusion: Heterogeneity measures computed on the post-contrast pre-operative T1 weighted MR images of patients with GBM are predictors of survival. Advances in knowledge: Texture analysis to assess tumour heterogeneity has been widely studied. However, most works develop a two-dimensional analysis, focusing only on one MRI slice to state tumour heterogeneity. The study of fully 3D heterogeneity textural features as predictors of clinical outcome is more robust and is not dependent on the selected slice of the tumour

    Submillimetric GPS distance measurement over short baselines: case study in inner consistency

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    Distance determination in the open air with submillimetric accuracy is a challenging task usually carried out with the use of submillimetric distancemeters and costly observation campaigns. The present paper represents a first step in the research of the potential use of GPS for submillimetric distance determination for distances up to a few hundred metres consisting in the evaluation of GPS distance determination reproducibility. As will be concluded, reliable submillimetric precision is attainable after some hours of observation if the same equipment in both baseline ends is used, even considering that there still remain some long-term systematic effects of a few tenths of a millimetre. The need for precise absolute antenna calibration values is also shown to be critical for submillimetric distance reproducibility.This research is funded by the Spanish Ministry of Science and Innovation (AYA2011-23232). The authors are grateful to the editor and the anonymous reviewers for their valuable suggestions, corrections and comments that helped improve the original manuscript.Baselga Moreno, S.; García-Asenjo Villamayor, L.; Garrigues Talens, P. (2013). Submillimetric GPS distance measurement over short baselines: case study in inner consistency. Measurement Science and Technology. 24(7):750011-750018. https://doi.org/10.1088/0957-0233/24/7/075001S750011750018247Amiri-Simkooei, A. R., & Tiberius, C. C. J. M. (2006). Assessing receiver noise using GPS short baseline time series. GPS Solutions, 11(1), 21-35. doi:10.1007/s10291-006-0026-8Bruyninx, C., Altamimi, Z., Boucher, C., Brockmann, E., Caporali, A., Gurtner, W., … Weber, G. (2009). The European Reference Frame: Maintenance and Products. International Association of Geodesy Symposia, 131-136. doi:10.1007/978-3-642-00860-3_20Doloca, N. R., Meiners-Hagen, K., Wedde, M., Pollinger, F., & Abou-Zeid, A. (2010). Absolute distance measurement system using a femtosecond laser as a modulator. Measurement Science and Technology, 21(11), 115302. doi:10.1088/0957-0233/21/11/115302Dow, J. M., Neilan, R. E., & Rizos, C. (2009). The International GNSS Service in a changing landscape of Global Navigation Satellite Systems. Journal of Geodesy, 83(3-4), 191-198. doi:10.1007/s00190-008-0300-3Firuzabadì, D., & King, R. W. (2011). GPS precision as a function of session duration and reference frame using multi-point software. GPS Solutions, 16(2), 191-196. doi:10.1007/s10291-011-0218-8Hyun, S., Kim, Y.-J., Kim, Y., Jin, J., & Kim, S.-W. (2009). Absolute length measurement with the frequency comb of a femtosecond laser. Measurement Science and Technology, 20(9), 095302. doi:10.1088/0957-0233/20/9/095302Koivula, H., Häkli, P., Jokela, J., Buga, A., & Putrimas, R. (2011). GPS Metrology: Bringing Traceable Scale to a Local Crustal Deformation GPS Network. International Association of Geodesy Symposia, 105-112. doi:10.1007/978-3-642-20338-1_13Ray, J., Altamimi, Z., Collilieux, X., & van Dam, T. (2007). Anomalous harmonics in the spectra of GPS position estimates. GPS Solutions, 12(1), 55-64. doi:10.1007/s10291-007-0067-7Schuhler, N., Salvadé, Y., Lévêque, S., Dändliker, R., & Holzwarth, R. (2006). Frequency-comb-referenced two-wavelength source for absolute distance measurement. Optics Letters, 31(21), 3101. doi:10.1364/ol.31.003101Snay, R. A., & Soler, T. (2008). Continuously Operating Reference Station (CORS): History, Applications, and Future Enhancements. Journal of Surveying Engineering, 134(4), 95-104. doi:10.1061/(asce)0733-9453(2008)134:4(95
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