In situ electrical characterization of palladium-based single electron transistors made by electromigration technique

We report the fabrication of single electron transistors (SETs) by feedback-controlled electromigration of palladium and palladium-nickel alloy nanowires. We have optimized a gradual electromigration process for obtaining devices consisting of three terminals (source, drain and gate electrodes), which are capacitively coupled to a metallic cluster of nanometric dimensions. This metal nanocluster forms into the inter-electrode channel during the electromigration process and constitutes the active element of each device, acting as a quantum dot that rules the electron flow between source and drain electrodes. The charge transport of the as-fabricated devices shows Coulomb blockade characteristics and the source to drain conductance can be modulated by electrostatic gating. We have thus achieved the fabrication and in situ measurement of palladium-based SETs inside a liquid helium cryostat chamber.Fil: Arzubiaga, L.. CIC nanoGUNE; EspañaFil: Golmar, Federico. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina. Instituto Nacional de Tecnología Industrial; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Llopis, R.. CIC nanoGUNE; EspañaFil: Casanova, F.. CIC nanoGUNE; España. IKERBASQUE; EspañaFil: Hueso, Luis E.. CIC nanoGUNE; España. IKERBASQUE; Españ

Propagation and nanofocusing of infrared surface plasmons on tapered transmission lines: Influence of the substrate

We study the propagation of mid-infrared surface plasmons on non-tapered and tapered two-wire transmission lines on Si and CaF 2 substrates, the two materials representing substrates with large and small refractive index, respectively. A comparative numerical study predicts a larger effective wavelength and an increased propagation length (i.e. weaker damping) for the CaF 2 substrate. By near-field microscopy we image the near-field distribution along the transmission lines and experimentally verify surface plasmon propagation. Amplitude- and phase-resolved near-field images of a non-tapered transmission line on CaF 2 reveal a standing wave pattern caused by back-reflection of the surface plasmons at the open-ended transmission line. Calculated and experimental near-field images of tapered transmission lines on Si and CaF 2 demonstrate that for both substrates the mid-IR surface plasmons are compressed when propagating along the taper. Importantly, the nanofocus at the taper apex yields a stronger local field enhancement for the low-refractive index substrate CaF 2. We assign the more efficient nanofocusing on CaF 2 to the weaker damping of the surface plasmons.Fil: Sarriugarte, P.. No especifíca;Fil: Schnell, M.. No especifíca;Fil: Alonso González, P.. No especifíca;Fil: Arzubiaga, L.. No especifíca;Fil: Golmar, Federico. Instituto Nacional de Tecnología Industrial; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Casanova, F.. No especifíca;Fil: Hueso, L. E.. No especifíca;Fil: Hillenbrand, R.. No especifíca

In situ electrical characterization of palladium-based single electron transistors made by electromigration technique

We report the fabrication of single electron transistors (SETs) by feedback-controlled electromigration of palladium and palladium-nickel alloy nanowires. We have optimized a gradual electromigration process for obtaining devices consisting of three terminals (source, drain and gate electrodes), which are capacitively coupled to a metallic cluster of nanometric dimensions. This metal nanocluster forms into the inter-electrode channel during the electromigration process and constitutes the active element of each device, acting as a quantum dot that rules the electron flow between source and drain electrodes. The charge transport of the as-fabricated devices shows Coulomb blockade characteristics and the source to drain conductance can be modulated by electrostatic gating. We have thus achieved the fabrication and in situ measurement of palladium-based SETs inside a liquid helium cryostat chamber.Fil: Arzubiaga, L.. CIC nanoGUNE; EspañaFil: Golmar, Federico. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina. Instituto Nacional de Tecnología Industrial; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Llopis, R.. CIC nanoGUNE; EspañaFil: Casanova, F.. CIC nanoGUNE; España. IKERBASQUE; EspañaFil: Hueso, Luis E.. CIC nanoGUNE; España. IKERBASQUE; Españ

[Ansiedad, depresión y estrés por COVID-19 en profesionales de la salud de Latinoamérica: Características y factores asociados]

La principal preocupación fue el regresar a casa y contagiar a su familia (22% muy de acuerdo), seguido por el sentir el maltrato porque no le dan la cantidad necesaria de equipos de protección personal (13% muy de acuerdo) y percibir agotamiento mental por todas las actividades que realizaba (12% muy de acuerdo). En el análisis multivariado, a mayor edad hubo una menor percepción de repercusión mental (RPa: 0,98; IC95%: 0,97-0,99; valor p=0,012); además, los que tuvieron una mayor percepción de repercusiones en la esfera mental también tuvieron más ansiedad en nivel bajo (RPa: 1,84; IC95%: 1,14-2,98; valor p=0,013) y estrés post traumático (RPa: 2,28; IC95%: 1,61-3,22; valor p<0,001), ajustado por la depresión y el estrés. A pesar de ser un análisis exploratorio, se encontró importantes asociaciones en la esfera mental; lo que debería seguir investigándose en estudios más extensos

Ansiedad, depresión y estrés COVID-19 en profesionales de la salud de Latinoamérica: características y factores asociados

Debido a la pandemia se ha reportado un aumento de los problemas de salud mental en miembros del personal de salud, siendo el autorreporte una forma inicial de evaluarlo. El objetivo fue el determinar los factores asociados a la percepción de repercusiones en la esfera mental en profesionales de la salud de Latinoamérica ante el COVID-19. Se ejecutó un estudio transversal analítico, entre junio y agosto del 2020 en Latinoamérica. Se midió la percepción de repercusiones a través de un instrumento previamente validado en Perú, que fue tomado de forma virtual a 406 médicos, enfermeras y otros; esto fue cruzado versus otras variables. La principal preocupación fue el regresar a casa y contagiar a su familia (22% muy de acuerdo), seguido por el sentir el maltrato porque no le dan la cantidad necesaria de equipos de protección personal (13% muy de acuerdo) y percibir agotamiento mental por todas las actividades que realizaba (12% muy de acuerdo). En el análisis multivariado, a mayor edad hubo una menor percepción de repercusión mental (RPa: 0,98; IC95%: 0,97-0,99; valor p=0,012); además, los que tuvieron una mayor percepción de repercusiones en la esfera mental también tuvieron más ansiedad en nivel bajo (RPa: 1,84; IC95%: 1,14-2,98; valor p=0,013) y estrés post traumático (RPa: 2,28; IC95%: 1,61-3,22; valor p<0,001), ajustado por la depresión y el estrés. A pesar de ser un análisis exploratorio, se encontró importantes asociaciones en la esfera mental; lo que debería seguir investigándose en estudios más extensos.Due to the pandemic, an increase in mental health problems has been reported in members of the health personnel, with the self-report being an initial way of evaluating it. The objective was to determine the factors associated with the perception of repercussions in the mental sphere in health professionals in Latin America before COVID-19. An analytical cross-sectional study was carried out between June and August 2020 in Latin America. The perception of repercussions was measured through an instrument previously validated in Peru, which was taken virtually from 406 doctors, nurses and others; this was crossed versus other variables. The main concern was returning home and infecting their family (22% strongly agree), followed by feeling the abuse because they do not give them the necessary amount of personal protective equipment (13% strongly agree) and perceiving mental exhaustion for all the activities they did (12% strongly agree). In the multivariate analysis, the older there was a lower perception of mental repercussion (aPR: 0.98; 95% CI: 0.97-0.99; p value = 0.012); In addition, those who had a greater perception of repercussions in the mental sphere also had more anxiety at a low level (aPR: 1.84; 95% CI: 1.14-2.98; p value = 0.013) and post-traumatic stress (aPR: 2.28; 95% CI: 1.61-3.22; p value <0.001), adjusted for depression and stress. Despite being an exploratory analysis, important associations were found in the mental sphere; which should continue to be investigated in larger studies

Nanoscale chemical mapping using three-dimensional adiabatic compression of surface plasmon polaritons

Abstract: We propose and demonstrate a novel photonic-plasmonic antenna capable of confining electromagnetic radiation at several mid-infrared wavelengths to a single sub-wavelength spot. The structure relies on the coupling between the localized surface plasmon resonance of a bow-tie nanoantenna with the photonic modes of surrounding multi-periodic particle arrays. Far-field measurements of the transmission through the central bowtie demonstrate the presence of Fano-like interference effects resulting from the interaction of the bow-tie antenna with the surrounding nanoparticle arrays. The near-field of the multi-wavelength antenna is imaged using an aperture-less near-field scanning optical microscope. This antenna is relevant for the development of near-field probes for nanoimaging, spectroscopy and biosensing. Hillenbrand, &quot;Nanoscale free-carrier profiling of individual semiconductor nanowires by infrared near-field nanoscopy,&quot; Nano Lett. 10(4), 1387-1392 (2010). 3. F. Huth, M. Schnell, J. Wittborn, N. Ocelic, and R. Hillenbrand, &quot;Infrared-spectroscopic nanoimaging with a thermal source,&quot; Nat. Mater. 10(5), 352-356 (2011). 4. S. Kawata and Y. Inouye, &quot;Scanning probe optical microscopy using a metallic probe tip,&quot; Ultramicroscopy 57(2-3), 313-317 (1995). 5. B. Knoll and F. Keilmann, &quot;Near-field probing of vibrational absorption for chemical microscopy,&quot; Nature 399(6732), 134-137 (1999). 6. F. Zenhausern, Y. Martin, and H. K. Wickramasinghe, &quot;Scanning interferometric apertureless microscopy: optical imaging at 10 angstrom resolution,&quot; Science 269(5227), 1083-1085 (1995). C. Andreani, and E. Di Fabrizio, &quot;Nanoscale chemical mapping using three-dimensional adiabatic compression of surface plasmon polaritons,&quot; Nat. Nanotechnol. 5(1), 67-72 (2010). 11. S. V. Boriskina and L. Dal Negro, &quot;Multiple-wavelength plasmonic nanoantennas,&quot; Opt. Lett. 35(4), 538-540 (2010). 12. D. T. Schaafsma, R. Mossadegh, J. S. Sanghera, I. D. Aggarwal, J. M. Gilligan, N. H. Tolk, M. Luce, R. ©2011 Optical Society of America Generosi, P. Perfetti, A. Cricenti, and G. Margaritondo, &quot;Singlemode chalcogenide fiber infrared SNOM probes,&quot; Ultramicroscopy 77(1-2), 77-81 (1999). 13. S. Zou and G. C. Schatz, &quot;Silver nanoparticle array structures that produce giant enhancements in electromagnetic fields,&quot; Chem. Phys