Periodic Arrays of Dopants in Silicon by Ultralow Energy Implantation of Phosphorus Ions through a Block Copolymer Thin Film.

In this work, block copolymer lithography and ultralow energy ion implantation are combined to obtain nanovolumes with high concentrations of phosphorus atoms periodically disposed over a macroscopic area in a p-type silicon substrate. The high dose of implanted dopants grants a local amorphization of the silicon substrate. In this condition, phosphorus is activated by solid phase epitaxial regrowth (SPER) of the implanted region with a relatively low temperature thermal treatment preventing diffusion of phosphorus atoms and preserving their spatial localization. Surface morphology of the sample (AFM, SEM), crystallinity of the silicon substrate (UV Raman), and position of the phosphorus atoms (STEM- EDX, ToF-SIMS) are monitored during the process. Electrostatic potential (KPFM) and the conductivity (C-AFM) maps of the sample surface upon dopant activation are compatible with simulated I-V characteristics, suggesting the presence of an array of not ideal but working p-n nanojunctions. The proposed approach paves the way for further investigations on the possibility to modulate the dopant distribution within a silicon substrate at the nanoscale by changing the characteristic dimension of the self-assembled BCP film.

Mental health assessment of Spanish frontline healthcare workers during the SARS-CoV-2 pandemic.

Background and objective: The Covid-19 pandemic continues challenging health systems globally, exposing healthcare workers to constant physical and psychological stressors. To date, several studies have already shown the catastrophic impact on the mental health of medical personnel during the early period of the pandemic. Nevertheless, literature evidences the dearth of works that evaluate the effect over time, understanding the pandemic as a sustained extreme stressor. The present study examines the effect of the pandemic on the mental health of Covid-19 frontline healthcare workers at six months follow-up. Material and methods: A total of 141 frontline healthcare workers from two tertiary hospitals were recruited between July and November 2020. Healthcare workers were evaluated psychologically at baseline and six months follow-up (January to May 2021) using psychometric tests for the assessment of acute stress (VASS, PSS-10, PCL-5), anxiety (STAI) and depression (PHQ-2). Results: Overall, there was a general worsening of the mental health between the two psychological assessments, especially regarding depression and predisposition to perceiving the situations as a threat. Nurses and nurse aides showed poorer mental health while physicians improved over time. Reduced working hours and higher physical exercise resulted in better mental health among healthcare workers. Women and nursing staff were the most affected by psychological distress at baseline and six months follow-up. Conclusion: Reduced working hours, adequate resting periods, physical exercise, and efficient intervention strategies are of utmost importance in preventing, controlling, and reducing psychological distress among healthcare workers when coping with critical scenarios such as the current pandemic.

Antecedentes y objetivo: La pandemia Covid-19 sigue desafiando a los sistemas sanitarios, exponiendo al personal asistencial a estresores físicos y psicológicos. Actualmente, varios estudios han demostrado el impacto catastrófico en la salud mental del personal asistencial durante la primera etapa de la pandemia, pero pocos han considerado el seguimiento de los síntomas. El presente estudio examina el efecto de la pandemia en la salud mental del personal sanitario de primera línea a los 6 meses de seguimiento. Material y métodos: Se evaluó psicológicamente a 141 trabajadores sanitarios de primera línea de 2 hospitales terciarios al inicio del estudio (julio-noviembre, 2020) y a los 6 meses (enero-mayo, 2021) mediante pruebas psicométricas para el estrés agudo (VASS, PSS-10, PCL-5), la ansiedad (STAI) y la depresión (PHQ-2). Resultados: En general, se observó un empeoramiento de la salud mental entre las 2 evaluaciones psicológicas, especialmente en depresión y predisposición a percibir las situaciones como una amenaza. La salud mental del personal de enfermería empeoró con el tiempo, mientras que los médicos mejoraron. La reducción de la jornada laboral y el aumento del ejercicio físico mejoraron la salud mental. Las mujeres y el personal de enfermería fueron los más afectados por el malestar psicológico al inicio y a los 6 meses de seguimiento. Conclusión: Jornadas laborales reducidas, períodos de descanso adecuados, ejercicio físico y estrategias de intervención eficientes son de suma importancia para prevenir, controlar y reducir el malestar psicológico entre el personal sanitario ante escenarios críticos como la pandemia actual.

Mental health assessment of Spanish frontline healthcare workers during the SARS-CoV-2 pandemic

Background and objectiveThe Covid-19 pandemic continues challenging health systems globally, exposing healthcare workers to constant physical and psychological stressors. To date, several studies have already shown the catastrophic impact on the mental health of medical personnel during the early period of the pandemic. Nevertheless, literature evidences the dearth of works that evaluate the effect over time, understanding the pandemic as a sustained extreme stressor. The present study examines the effect of the pandemic on the mental health of Covid-19 frontline healthcare workers at six months follow-up.Material and methodsA total of 141 frontline healthcare workers from two tertiary hospitals were recruited between July and November 2020. Healthcare workers were evaluated psychologically at baseline and six months follow-up (January to May 2021) using psychometric tests for the assessment of acute stress (VASS, PSS-10, PCL-5), anxiety (STAI) and depression (PHQ-2)ResultsOverall, there was a general worsening of the mental health between the two psychological assessments, especially regarding depression and predisposition to perceiving the situations as a threat. Nurses and nurse aides showed poorer mental health while physicians improved over time. Reduced working hours and higher physical exercise resulted in better mental health among healthcare workers. Women and nursing staff were the most affected by psychological distress at baseline and six months follow-up.ConclusionReduced working hours, adequate resting periods, physical exercise, and efficient intervention strategies are of utmost importance in preventing, controlling, and reducing psychological distress among healthcare workers when coping with critical scenarios such as the current pandemic. (AU)

Antecedentes y objetivoLa pandemia Covid-19 sigue desafiando a los sistemas sanitarios, exponiendo al personal asistencial a estresores físicos y psicológicos. Actualmente, varios estudios han demostrado el impacto catastrófico en la salud mental del personal asistencial durante la primera etapa de la pandemia, pero pocos han considerado el seguimiento de los síntomas. El presente estudio examina el efecto de la pandemia en la salud mental del personal sanitario de primera línea a los 6 meses de seguimiento.Material y métodosSe evaluó psicológicamente a 141 trabajadores sanitarios de primera línea de 2 hospitales terciarios al inicio del estudio (julio-noviembre, 2020) y a los 6 meses (enero-mayo, 2021) mediante pruebas psicométricas para el estrés agudo (VASS, PSS-10, PCL-5), la ansiedad (STAI) y la depresión (PHQ-2).ResultadosEn general, se observó un empeoramiento de la salud mental entre las 2 evaluaciones psicológicas, especialmente en depresión y predisposición a percibir las situaciones como una amenaza. La salud mental del personal de enfermería empeoró con el tiempo, mientras que los médicos mejoraron. La reducción de la jornada laboral y el aumento del ejercicio físico mejoraron la salud mental. Las mujeres y el personal de enfermería fueron los más afectados por el malestar psicológico al inicio y a los 6 meses de seguimiento.ConclusiónJornadas laborales reducidas, períodos de descanso adecuados, ejercicio físico y estrategias de intervención eficientes son de suma importancia para prevenir, controlar y reducir el malestar psicológico entre el personal sanitario ante escenarios críticos como la pandemia actual. (AU)

Mental health assessment of Spanish frontline healthcare workers during the SARS-CoV-2 pandemic.

BACKGROUND AND OBJECTIVE: The Covid-19 pandemic continues challenging health systems globally, exposing healthcare workers to constant physical and psychological stressors. To date, several studies have already shown the catastrophic impact on the mental health of medical personnel during the early period of the pandemic. Nevertheless, literature evidences the dearth of works that evaluate the effect over time, understanding the pandemic as a sustained extreme stressor. The present study examines the effect of the pandemic on the mental health of Covid-19 frontline healthcare workers at six months follow-up. MATERIAL AND METHODS: A total of 141 frontline healthcare workers from two tertiary hospitals were recruited between July and November 2020. Healthcare workers were evaluated psychologically at baseline and six months follow-up (January to May 2021) using psychometric tests for the assessment of acute stress (VASS, PSS-10, PCL-5), anxiety (STAI) and depression (PHQ-2) RESULTS: Overall, there was a general worsening of the mental health between the two psychological assessments, especially regarding depression and predisposition to perceiving the situations as a threat. Nurses and nurse aides showed poorer mental health while physicians improved over time. Reduced working hours and higher physical exercise resulted in better mental health among healthcare workers. Women and nursing staff were the most affected by psychological distress at baseline and six months follow-up. CONCLUSION: Reduced working hours, adequate resting periods, physical exercise, and efficient intervention strategies are of utmost importance in preventing, controlling, and reducing psychological distress among healthcare workers when coping with critical scenarios such as the current pandemic.

Mental health assessment of Spanish healthcare workers during the SARS-CoV-2 pandemic. A cross-sectional study.

INTRODUCTION: The SARS-CoV-2 outbreak is posing unprecedented care scenarios, increasing the psychological distress among healthcare workers while reducing the efficiency of health systems. This work evaluated the psychological impact of the Covid-19 pandemic on Spanish frontline healthcare workers of two tertiary hospitals. MATERIAL AND METHODS: Healthcare workers were recruited from the medical units designated for the care of Covid-19 patients. The psychological assessment consisted of an individual, face-to-face session where gold-standard psychometric tests were administered to assess stress (VASS & PSS-10), anxiety (STAI), depression (PHQ-2) and posttraumatic stress disorder (PCL-5). Regression models were also fitted to identify predictors of psychological distress. RESULTS: Overall, almost 13% of healthcare workers showed severe anxiety, while more than 26% had high levels of perceived stress. More than 23% presented severe posttraumatic stress symptoms, and another 13% had PHQ-2 scores equal to or above 3, compatible with Major Depressive Disorder (MDD) diagnosis, respectively. Women, stress-related medication, overworking, performing in Covid-19 wards, and substance abuse were risk factors for increased psychological distress. Instead, practising exercise reduced the burden. CONCLUSION: This study outlines the severe psychological impact of the Covid-19 pandemic on Spanish frontline healthcare workers. The stress, depression and anxiety levels found were similar to those reported in similar works but much higher than in Wuhan healthcare workers. Knowledge of risk factors for increased psychological distress may help to develop comprehensive intervention strategies to prevent, control and reduce the mental health exacerbation of healthcare workers, thereby maintaining the effectiveness of health systems in critical scenarios.

Design and validation of an electrophysiological based tool to assess chronic stress. Case study: burnout syndrome in caregivers.

Caregiver burnout syndrome is an increasingly seen condition, although the subjective nature of self-administered psychometric tests and the lack of a consensual diagnostic tool might hinder a proper diagnosis. The availability of objective psychosomatic measures of stress might facilitate the early diagnosis and clinical management of these patients. For this reason, the aim of this work was to develop a quantitative tool to evaluate the stress level of caregivers in a noninvasive and repeatable manner. An observational, controlled, matched study was designed including a group of 38 principal caregivers of chronic patients and a control group of 38 non-caregivers. Psychometric, biochemical, and electrophysiological data were analyzed along with sociodemographic data. A quantitative chronic stress reference scale (CSRs) was constructed based on the weighted contribution of several psychometric and biochemical variables and afterwards, a predictive psychosomatic model (ESBSm) correlated with CSRs was elaborated from extracted variables of several electrophysiological signals monitored for 10 min. The resulting CSR scale shows a high power to discriminate caregivers from the control group while the ESBSm shows a 79% correlation with the CSR scale validated through a 5-fold process. Therefore, the results demonstrate that the ESBS model is an objective and validated tool to diagnose the degree of stress linked to burnout in caregivers of chronic patients from a 10-min session of noninvasive monitoring with a reliability equivalent to the questionnaires currently used to quantify stress in caregivers.

Multi-Frequency Resonance Behaviour of a Si FractalNEMS Resonator.

Novel Si-based nanosize mechanical resonator has been top-down fabricated. The shapeof the resonating body has been numerically derived and consists of seven star-polygons that forma fractal structure. The actual resonator is defined by focused ion-beam implantation on a SOIwafer where its 18 vertices are clamped to nanopillars. The structure is suspended over a 10 mtrench and has width of 12 m. Its thickness of 0.040 m is defined by the fabrication process andprescribes Young's modulus of 76 GPa which is significantly lower than the value of the bulk material.The resonator is excited by the bottom Si-layer and the interferometric characterisation confirmsbroadband frequency response with quality factors of over 800 for several peaks between 2 MHzand 16 MHz. COMSOL FEM software has been used to vary material properties and residual stressin order to fit the eigenfrequencies of the model with the resonance peaks detected experimentally.Further use of the model shows how the symmetry of the device affects the frequency spectrum.Also, by using the FEM model, the possibility for an electrical read out of the device was tested. Theexperimental measurements and simulations proved that the device can resonate at many differentexcitation frequencies allowing multiple operational bands. The size, and the power needed foractuation are comparable with the ones of single beam resonator while the fractal structure allowsmuch larger area for functionalisation.

Building on Margalef: Testing the links between landscape structure, energy and information flows driven by farming and biodiversity.

The aim of this paper is to test two methodologies, applicable to different spatial scales (from regional to local), to predict the capacity of agroecosystems to provide habitats for the species richness of butterflies and birds, based on the ways their socio-metabolic flows change the ecological functionality of bio-cultural landscapes. First, we use the more general Intermediate Disturbance-Complexity (IDC) model to assess how different levels of human appropriation of photosynthetic production affect the landscape functional structure that hosts biodiversity. Second, we apply a more detailed Energy-Landscape Integrated Analysis (ELIA) model that focusses on the energy storage carried out by the internal biomass loops, and the energy information held in the network of energy flows driven by farmers, in order to correlate both (the energy reinvested and redistributed) with the energy imprinted in the landscape patterns and processes that sustain biodiversity. The results obtained after applying both models in the province and the metropolitan region of Barcelona support the Margalef's energy-information-structure hypothesis by showing positive relations between butterflies' species richness, IDC and ELIA, and between birds' species richness and energy information. Our findings support the view that strong relationships between farming energy flows, agroecosystem functioning and biodiversity can be detected, and highlight the importance of farmers' knowledge and labour to maintain bio-cultural landscapes.

Efficient light trapping and broadband absorption of the solar spectrum in nanopillar arrays decorated with deep-subwavelength sidewall features.

Silicon nanopillar (NP) arrays are known to exhibit efficient light trapping and broadband absorption of solar radiation. In this study, we consider the effect of deep subwavelength sidewall scalloping (DSSS) on the broadband absorption of the arrays. Practically, the formation of DSSS is a side effect of top-down dry etching of NP arrays of several microns height. We use finite-difference time-domain electromagnetic calculations to show that the presence of DSSS can result in efficient excitation of optical modes in both the arrays and the underlying substrates. We demonstrate a broadband absorption enhancement of >10% in a DSSS-NP array with an underlying substrate. Finally, we use device calculations to examine the effect of DSSS on the electrical performance of a photovoltaic cell, as the main concern is the degradation of the open-circuit voltage due to surface recombination (DSSS results in higher surface-to-volume ratio). We show that the effect of DSSS on open-circuit voltage is negligible. Finally, deep-subwavelength sidewall features offer a new, interesting photon management strategy towards absorption enhancement.

Laser Fabrication of Polymer Ferroelectric Nanostructures for Nonvolatile Organic Memory Devices.

Polymer ferroelectric laser-induced periodic surface structures (LIPSS) have been prepared on ferroelectric thin films of a poly(vinylidene fluoride-trifluoroethylene) copolymer. Although this copolymer does not absorb light at the laser wavelength, LIPSS on the copolymer can be obtained by forming a bilayer with other light-absorbing polymers. The ferroelectric nature of the structured bilayer was proven by piezoresponse force microscopy measurements. Ferroelectric hysteresis was found on both the bilayer and the laser-structured bilayer. We show that it is possible to write ferroelectric information at the nanoscale. The laser-structured ferroelectric bilayer showed an increase in the information storage density of an order of magnitude, in comparison to the original bilayer.

Top-down silicon microcantilever with coupled bottom-up silicon nanowire for enhanced mass resolution.

A stepped cantilever composed of a bottom-up silicon nanowire coupled to a top-down silicon microcantilever electrostatically actuated and with capacitive or optical readout is fabricated and analyzed, both theoretically and experimentally, for mass sensing applications. The mass sensitivity at the nanowire free end and the frequency resolution considering thermomechanical noise are computed for different nanowire dimensions. The results obtained show that the coupled structure presents a very good mass sensitivity thanks to the nanowire, where the mass depositions take place, while also presenting a very good frequency resolution due to the microcantilever, where the transduction is carried out. A two-fold improvement in mass sensitivity with respect to that of the microcantilever standalone is experimentally demonstrated, and at least an order-of-magnitude improvement is theoretically predicted, only changing the nanowire length. Very close frequency resolutions are experimentally measured and theoretically predicted for a standalone microcantilever and for a microcantilever-nanowire coupled system. Thus, an improvement in mass sensing resolution of the microcantilever-nanowire stepped cantilever is demonstrated with respect to that of the microcantilever standalone.

High-sensitivity linear piezoresistive transduction for nanomechanical beam resonators.

Highly sensitive conversion of motion into readable electrical signals is a crucial and challenging issue for nanomechanical resonators. Efficient transduction is particularly difficult to realize in devices of low dimensionality, such as beam resonators based on carbon nanotubes or silicon nanowires, where mechanical vibrations combine very high frequencies with miniscule amplitudes. Here we describe an enhanced piezoresistive transduction mechanism based on the asymmetry of the beam shape at rest. We show that this mechanism enables highly sensitive linear detection of the vibration of low-resistivity silicon beams without the need of exceptionally large piezoresistive coefficients. The general application of this effect is demonstrated by detecting multiple-order modes of silicon nanowire resonators made by either top-down or bottom-up fabrication methods. These results reveal a promising approach for practical applications of the simplest mechanical resonators, facilitating its manufacturability by very large-scale integration technologies.