Unveiling the crystal and magnetic texture of iron oxide nanoflowers.

Iron oxide nanoflowers (IONF) are densely packed multi-core aggregates known for their high saturation magnetization and initial susceptibility, as well as low remanence and coercive field. This study reports on how the local magnetic texture originating at the crystalline correlations among the cores determines the special magnetic properties of individual IONF over a wide size range from 40 to 400 nm. Regardless of this significant size variation in the aggregates, all samples exhibit a consistent crystalline correlation that extends well beyond the IONF cores. Furthermore, a nearly zero remnant magnetization, together with the presence of a persistently blocked state, and almost temperature-independent field-cooled magnetization, support the existence of a 3D magnetic texture throughout the IONF. This is confirmed by magnetic transmission X-ray microscopy images of tens of individual IONF, showing, in all cases, a nearly demagnetized state caused by the vorticity of the magnetic texture. Micromagnetic simulations agree well with these experimental findings, showing that the interplay between the inter-core direct exchange coupling and the demagnetizing field is responsible for the highly vortex-like spin configuration that stabilizes at low magnetic fields and appears to have partial topological protection. Overall, this comprehensive study provides valuable insights into the impact of crystalline texture on the magnetic properties of IONF over a wide size range, offering a deeper understanding of their potential applications in fields such as biomedicine and water remediation.

Grado de conocimientos sobre el riesgo de conducta suicida de los profesionales de Atención Primaria en un área de salud / [Degree of knowledge about the risk of suicidal behavior of Primary Care professionals in a health area]

Introducción: En los últimos años ha aumentado el número de suicidios en nuestro país con 4003 suicidios en 2021 (el mayor número desde que existen datos), representando también la 1ª causa de muerte externa. A su vez un 77% de las personas que se suicidan tuvieron contacto con algún profesional de atención primaria en el año previo y un 45% el mes previo al suicidio. Material y método: Se empleó un formulario autoadministrado de Google para recoger información acerca del conocimiento de la conducta e ideación suicida, los factores de riesgo y las acciones que se llevan a cabo ante esta situación en Atención Primaria por parte de los profesionales de Enfermería y Medicina. Resultados: A través de la encuesta autoadministrada, se concluyó que casi la totalidad de los participantes están de acuerdo en la relevancia del aumento del número de suicidios en 2022 en España. Más del 50% de la muestra afirma tener un conocimiento escaso o ningún conocimiento acerca de la conducta de riesgo suicida, su detección y abordaje desde Atención Primaria. Además, más del 75% indica no haber recibido formación sobre la prevención de la ideación suicida, considerando necesaria una preparación específica para el adecuado abordaje en la prevención y atención del riesgo de suicidio. Conclusiones: La presente investigación identifica la necesidad de una mayor formación de los profesionales de Atención Primaria en el área de salud estudiada, para realizar un correcto abordaje del paciente suicida. (AU)

Caso clínico: “Nadie lo hará por mí” / [Clinical case: “No one will do it for me”]

La adherencia terapéutica, es un hecho variante y complejo ya que son diversos los factores que influyen en él. En los países desarrollados la adherencia terapéutica de los pacientes que padecen enfermedades crónicas es del 50%, requiriendo acciones de prevención y promoción de la salud, que se ven intensificadas cuando la falta de adherencia terapéutica está unida al abuso de sustancias y la dependencia de alcohol. El señor D.R. es un paciente varón de 69 años con paresia crural izquierda, trastorno de la marcha, dependencia para las ABVD y AIVD, HTA, ateromatosis carotidea, mala adherencia terapéutica, abuso de alcohol, sobrepeso e hipercolesterolemia, que ingresa en el hospital en el servicio de Neurología tras sufrir un ictus isquémico. Durante este ingreso, se distingue el progreso en el nivel de implicación y compromiso del paciente con su propia salud. A través de la taxonomía NANDA-I, NOC y NIC, se llevó a cabo un plan de cuidados, aplicando un lenguaje estandarizado y con intervenciones basadas en la evidencia científica. (AU)

Imaging of Antiferroelectric Dark Modes in an Inverted Plasmonic Lattice.

Plasmonic lattice nanostructures are of technological interest because of their capacity to manipulate light below the diffraction limit. Here, we present a detailed study of dark and bright modes in the visible and near-infrared energy regime of an inverted plasmonic honeycomb lattice by a combination of Au+ focused ion beam lithography with nanometric resolution, optical and electron spectroscopy, and finite-difference time-domain simulations. The lattice consists of slits carved in a gold thin film, exhibiting hotspots and a set of bright and dark modes. We proposed that some of the dark modes detected by electron energy-loss spectroscopy are caused by antiferroelectric arrangements of the slit polarizations with two times the size of the hexagonal unit cell. The plasmonic resonances take place within the 0.5-2 eV energy range, indicating that they could be suitable for a synergistic coupling with excitons in two-dimensional transition metal dichalcogenides materials or for designing nanoscale sensing platforms based on near-field enhancement over a metallic surface.

Selective anisotropic growth of Bi2S3 nanoparticles with adjustable optical properties.

We report on the controlled synthesis and functionalization in two steps of elongated Bi2S3 nanoparticles within a wide range of sizes. First, we show the effect of the temperature and reaction time on the synthesis of two series of nanoparticles by the reaction of thioacetamide with bismuth(III) neodecanoate in the presence of organic surfactants. At 105 °C and long reaction times, nanoneedles of about 45 nm in length containing larger crystallites are obtained, while highly crystalline nanorods of about 30 nm in length are dominant at 165 °C, regardless of the reaction time. The optical properties of both types of nanoparticles show an enhancement of the band gap compared to bulk Bi2S3. This is likely to arise from quantum confinement effects caused by the small particle dimensions relative to the typical exciton size, together with an increase in near-infrared absorption due to the anisotropic particle shape. Second, a ligand exchange approach has been developed to transfer the Bi2S3 nanoparticles to aqueous solutions by grafting dimercaptosuccinic acid onto the surface of the particles. The as-prepared coated nanoparticles show good stability in water, in a wide biological pH range, and in phosphate-buffered saline solutions. Overall, this work highlights the controlled design at all levels - from the inorganic core to the organic surface coating - of elongated Bi2S3 nanoparticles, leading to a tunable optical response by tuning their morphology and size.

A pesar del tratamiento no mejoro / Despite the treatment, i did not improve

Las caídas son un problema de salud pública de primer orden, y su pre vención es algo clave en el manejo de las mismas. El paciente protagonista del caso clínico ha tenido una caída casual en el baño de su domicilio lo que le ha provocado una fractura de cadera y, por tanto, una pérdida de independencia y calidad de vida. Para su valoración se utilizó la Teoría de Rango Medio de “Los síntomas desagradables” cuya autoría lidera la enfermera y doctora en sociolo gía Elisabeth Lenz y teniendo a Linda Pugh, Renee Milligan y Andreu Gift como colaboradoras. Tras esto, se realiza un plan de cuidados individualizado utilizan do el lenguaje estandarizado enfermero NANDA, NOC y NIC. Finalmente, el pa ciente es capaz de conseguir una mejora en su salud a través de la adhesión al plan y de nuestra intervención desde el ámbito familiar y comunitario (AU)

Falls are a public health problem, and their prevention is key in managing them. Out patient suffers a casual fall in the bathroom of his home that ends with a hip fracture and therefore a loss of in dependence and quality of life. For its assessment, the “Mid-Range Theory of Unpleasant Symptoms” is used, whose authorship is led by the nurse and doctor in sociology Elisabeth Lenz and she has to Linda Pugh, Renee Milligan and An dreu Gift as collaborators. A care plan is made through the standardized languages NANDA, NOC and NIC. The patient achieved an impro vement in his health through adherence to the plan and our intervention from the community setting (AU)

Tunable circular dichroism through absorption in coupled optical modes of twisted triskelia nanostructures.

We present a system consisting of two stacked chiral plasmonic nanoelements, so-called triskelia, that exhibits a high degree of circular dichroism. The optical modes arising from the interactions between the two elements are the main responsible for the dichroic signal. Their excitation in the absorption cross section is favored when the circular polarization of the light is opposite to the helicity of the system, so that an intense near-field distribution with 3D character is excited between the two triskelia, which in turn causes the dichroic response. Therefore, the stacking, in itself, provides a simple way to tune both the value of the circular dichroism, up to 60%, and its spectral distribution in the visible and near infrared range. We show how these interaction-driven modes can be controlled by finely tuning the distance and the relative twist angle between the triskelia, yielding maximum values of the dichroism at 20° and 100° for left- and right-handed circularly polarized light, respectively. Despite the three-fold symmetry of the elements, these two situations are not completely equivalent since the interplay between the handedness of the stack and the chirality of each single element breaks the symmetry between clockwise and anticlockwise rotation angles around 0°. This reveals the occurrence of clear helicity-dependent resonances. The proposed structure can be thus finely tuned to tailor the dichroic signal for applications at will, such as highly efficient helicity-sensitive surface spectroscopies or single-photon polarization detectors, among others.

Stochastic vs. deterministic magnetic coding in designed cylindrical nanowires for 3D magnetic networks.

Advances in cylindrical nanowires for 3D information technologies profit from intrinsic curvature that introduces significant differences with regards to planar systems. A model is proposed to control the stochastic and deterministic coding of remanent 3D complex vortex configurations in designed multilayered (magnetic/non-magnetic) cylindrical nanowires. This concept, introduced by micromagnetic simulations, is experimentally confirmed by magnetic imaging in FeCo/Cu multilayered nanowires. The control over the random/deterministic vortex states configurations is achieved by a suitable geometrical interface tilting of almost non-interacting FeCo segments with respect to the nanowire axis, together with the relative orientation of the perpendicular magnetic field. The proper design of the segments' geometry (e.g. tilting) in cylindrical nanowires opens multiple opportunities for advanced nanotechnologies in 3D magnetic networks.

An Inverted Honeycomb Plasmonic Lattice as an Efficient Refractive Index Sensor.

We present an efficient refractive index sensor consisting of a heterostructure that contains an Au inverted honeycomb lattice as a main sensing element. Our design aims at maximizing the out-of-plane near-field distributions of the collective modes of the lattice mapping the sensor surroundings. These modes are further enhanced by a patterned SiO2 layer with the same inverted honeycomb lattice, an SiO2 spacer, and an Au mirror underneath the Au sensing layer that contribute to achieving a high performance. The optical response of the heterostructure was studied by numerical simulation. The results corresponding to one of the collective modes showed high sensitivity values ranging from 99 to 395 nm/RIU for relatively thin layers of test materials within 50 and 200 nm. In addition, the figure of merit of the sensor detecting slight changes of the refractive index of a water medium at a fixed wavelength was as high as 199 RIU-1. As an experimental proof of concept, the heterostructure was manufactured by a simple method based on electron beam lithography and the measured optical response reproduces the simulations. This work paves the way for improving both the sensitivity of plasmonic sensors and the signal of some enhanced surface spectroscopies.

Driving magnetic domains at the nanoscale by interfacial strain-induced proximity.

We investigate the local nanoscale changes of the magnetic anisotropy of a Ni film subject to an inverse magnetostrictive effect by proximity to a V2O3 layer. Using temperature-dependent photoemission electron microscopy (PEEM) combined with X-ray magnetic circular dichroism (XMCD), direct images of the Ni spin alignment across the first-order structural phase transition (SPT) of V2O3 were obtained. We find an abrupt temperature-driven reorientation of the Ni magnetic domains across the SPT, which is associated with a large increase of the coercive field. Moreover, angular dependent ferromagnetic resonance (FMR) shows a remarkable change in the magnetic anisotropy of the Ni film across the SPT of V2O3. Micromagnetic simulations based on these results are in quantitative agreement with the PEEM data. Direct measurements of the lateral correlation length of the Ni domains from XMCD images show an increase of almost one order of magnitude at the SPT compared to room temperature, as well as a broad spatial distribution of the local transition temperatures, thus corroborating the phase coexistence of Ni anisotropies caused by the V2O3 SPT. We show that the rearrangement of the Ni domains is due to strain induced by the oxide layers' structural domains across the SPT. Our results illustrate the use of alternative hybrid systems to manipulate magnetic domains at the nanoscale, which allows for engineering of coercive fields for novel data storage architectures.

Selective Control over the Morphology and the Oxidation State of Iron Oxide Nanoparticles.

Iron oxide nanoparticles (NPs) have been extensively used for both health and technological applications. The control over their morphology, crystal microstructure, and oxidation state is of great importance to optimize their final use. However, while mature in understanding, it is still far from complete. Here we report on the effect of the amount of 1,2-hexadecanediol and/or 1-octadecene in the reaction mixture on the thermal decomposition of iron(III) acetylacetonate in oleic acid for two series of iron oxide NPs with sizes ranging from 6 to 48 nm. We show that a low amount of either compound leads to both large, mixed-phase NPs composed of magnetite (Fe3O4) and wüstite (FeO) and high reaction yields. In contrast, a higher amount of either 1,2-hexadecanediol or 1-octadecene gives rise to smaller, single-phase NPs with moderate reaction yields. By infrared spectroscopy, we have elucidated the role of 1,2-hexadecanediol, which mediates the particle nucleation and growth. Finally, we have correlated the magnetic response and the structural features of the NPs for the two series of samples.

Unveiling the Origin of Multidomain Structures in Compositionally Modulated Cylindrical Magnetic Nanowires.

CoNi/Ni multisegmented cylindrical nanowires were synthesized via an electrochemical route. The wires are 140 nm in diameter, with 1000 nm long Ni segments and CoNi segments between 600 and 1400 nm in length. The magnetic configuration was imaged by XMCD-PEEM in the demagnetized state and at remanence after magnetizing axially and perpendicularly. Ni segments, with cubic crystal symmetry, show an axial magnetic configuration with a small curling component at the surface. In turn, CoNi segments, with hexagonal crystal symmetry and a strong magnetocrystalline anisotropy perpendicular to the nanowires, show a single vortex state in the shorter segments and multivortex or multitransverse magnetic configurations in medium and long segments, respectively. A detailed study by micromagnetic simulations reveals that the magnetic configuration is determined mainly by the coupling between soft Ni and harder CoNi segments. For short CoNi segments, Ni segments are magnetostatically coupled and the chirality of the single vortex formed in CoNi remains the same as that of the curling in neighboring Ni segments. For longer CoNi segments, the remanent state is either the multivortex or multitransverse state depending on whether the previously applied field was parallel or perpendicular to the magnetocrystalline axis. The results point out the relevance of the cylindrical geometry to promote the occurrence of complex magneto-chiral effects and provide key information for the design of cylindrical magnetic nanowires for multiple applications.

Genome-wide association meta-analyses combining multiple risk phenotypes provide insights into the genetic architecture of cutaneous melanoma susceptibility.

Most genetic susceptibility to cutaneous melanoma remains to be discovered. Meta-analysis genome-wide association study (GWAS) of 36,760 cases of melanoma (67% newly genotyped) and 375,188 controls identified 54 significant (P < 5 × 10-8) loci with 68 independent single nucleotide polymorphisms. Analysis of risk estimates across geographical regions and host factors suggests the acral melanoma subtype is uniquely unrelated to pigmentation. Combining this meta-analysis with GWAS of nevus count and hair color, and transcriptome association approaches, uncovered 31 potential secondary loci for a total of 85 cutaneous melanoma susceptibility loci. These findings provide insights into cutaneous melanoma genetic architecture, reinforcing the importance of nevogenesis, pigmentation and telomere maintenance, together with identifying potential new pathways for cutaneous melanoma pathogenesis.

Geometric frustration in ordered lattices of plasmonic nanoelements.

Inspired by geometrically frustrated magnetic systems, we present the optical response of three cases of hexagonal lattices of plasmonic nanoelements. All of them were designed using a metal-insulator-metal configuration to enhance absorption of light, with elements in close proximity to exploit near-field coupling, and with triangular symmetry to induce frustration of the dipolar polarization in the gaps between neighboring structures. Both simulations and experimental results demonstrate that these systems behave as perfect absorbers in the visible and/or the near infrared. Besides, the numerical study of the time evolution shows that they exhibit a relatively extended time response over which the system fluctuates between localized and collective modes. It is of particular interest the echoed excitation of surface lattice resonance modes, which are still present at long times because of the geometric frustration inherent to the triangular lattice. It is worth noting that the excitation of collective modes is also enhanced in other types of arrays where dipolar excitations of the nanoelements are hampered by the symmetry of the array. However, we would like to emphasize that the enhancement in triangular arrays can be significantly larger because of the inherent geometric incompatibility of dipolar excitations and three-fold symmetry axes.

Geometric frustration in a hexagonal lattice of plasmonic nanoelements.

We introduce the concept of geometric frustration in plasmonic arrays of nanoelements. In particular, we present the case of a hexagonal lattice of Au nanoasterisks arranged so that the gaps between neighboring elements are small and lead to a strong near-field dipolar coupling. Besides, far-field interactions yield higher-order collective modes around the visible region that follow the translational symmetry of the lattice. However, dipolar excitations of the gaps in the hexagonal array are geometrically frustrated for interactions beyond nearest neighbors, yielding the destabilization of the low energy modes in the near infrared. This in turn results in a slow dynamics of the optical response and a complex interplay between localized and collective modes, a behavior that shares features with geometrically frustrated magnetic systems.

Magnetization Ratchet in Cylindrical Nanowires.

The unidirectional motion of information carriers such as domain walls in magnetic nanostrips is a key feature for many future spintronic applications based on shift registers. This magnetic ratchet effect has so far been achieved in a limited number of complex nanomagnetic structures, for example, by lithographically engineered pinning sites. Here we report on a simple remagnetization ratchet originated in the asymmetric potential from the designed increasing lengths of magnetostatically coupled ferromagnetic segments in FeCo/Cu cylindrical nanowires. The magnetization reversal in neighboring segments propagates sequentially in steps starting from the shorter segments, irrespective of the applied field direction. This natural and efficient ratchet offers alternatives for the design of three-dimensional advanced storage and logic devices.

Preparation of Alkyl Alkynyl Sulfones and Cyclic Vinyl Sulfones from Alkynyl(aryl)iodonium Salts.

The reaction of alkyl sulfinates with alkynyl(aryl)iodonium salts provides a facile access into otherwise difficult to obtain alkyl alkynyl sulfones and cyclic vinyl sulfones via 1,2-rearrangement or 1,5-CH insertion, respectively. In benzyl sulfinates, 1,5-CH insertion is not possible, so addition to the aromatic ring occurs, followed by ring expansion to generate novel bicyclic sulfones.

Direct observation of magnetic metastability in individual iron nanoparticles.

X-ray photoemission electron microscopy combined with x-ray magnetic circular dichroism is used to study the magnetic properties of individual iron nanoparticles with sizes ranging from 20 down to 8 nm. While the magnetocrystalline anisotropy of bulk iron suggests superparamagnetic behavior in this size range, ferromagnetically blocked particles are also found at all sizes. Spontaneous transitions from the blocked state to the superparamagnetic state are observed in single particles and suggest that the enhanced magnetic energy barriers in the ferromagnetic particles are due to metastable, structurally excited states with unexpected life times.

Hypoiodous acid initiated rearrangement of tertiary propargylic alcohols to α-iodoenones.

In the presence of an oxidant, sodium iodide is converted into hypoiodous acid which effects the rearrangement of tertiary propargylic alcohols to α-iodoenones in good yields.

Iodobenzene-catalyzed intramolecular oxidative cyclization reactions of δ-alkynyl ß-ketoesters.

Iodobenzene is shown to catalyze the 5-exo-dig cyclization of δ-alkynyl ß-ketoesters under oxidative conditions that generate hypervalent iodine species in situ. The cyclopentane products contain adjacent quaternary and tertiary stereocenters which are generated with excellent diastereoselectivity.