Current rectification in molecular junctions produced by local potential fields

The transport properties of a octane-dithiol (ODT) molecule coupled to Au(001) leads are analyzed using density functional theory and non-equilibrium Green functions. It is shown that a symmetric molecule can turn into a diode under influence of a local electric field created by an external charged probe. The origin of the asymmetry of the current--voltage ($I-V$) dependence is traced back to the appearance of a probe induced quasi--local state in the pseudogap of the ODT molecule. The induced state affects electron transport, provided it is close to the Fermi level of the leads. An asymmetric placement of the charged probe along the alkane chain makes the induced quasi--local state in the energy gap very sensitive to the bias voltage and results in rectification of the current. The results based on DFT are supported by independent calculations using a simple one--particle model Hamiltonian.Comment: 7 pages, 6 figure

Tuning the electrical conductivity of nanotube-encapsulated metallocene wires

We analyze a new family of carbon nanotube-based molecular wires, formed by encapsulating metallocene molecules inside the nanotubes. Our simulations, that are based on a combination of non-equilibrium Green function techniques and density functional theory, indicate that these wires can be engineered to exhibit desirable magnetotransport effects for use in spintronics devices. The proposed structures should also be resilient to room-temperature fluctuations, and are expected to have a high yield.Comment: 4 pages, 6 figures. Accepted in Physical Review Letter

Epidemiologic surveillance of nosocomial infections in a Pediatric Intensive Care Unit of a developing country

<p>Abstract</p> <p>Background</p> <p>Nosocomial Infections (NI) are a frequent and relevant problem. The purpose of this study was to determine the epidemiology of the three most common NI in a Pediatric Intensive Care Unit from a developing country.</p> <p>Methods</p> <p>We performed a prospective study in a single Pediatric Intensive Care Unit during 12 months. Children were assessed for 3 NI: bloodstream infections (BSI), ventilator-associated pneumonia (VAP) and urinary tract infections (UTI), according to Center for Disease Control criteria. Use of devices (endotracheal tube [ETT], central venous catheter [CVC] and urinary catheter [UC]) was recorded.</p> <p>Results</p> <p>Four hundred fourteen patients were admitted; 81 patients (19.5%) developed 85 NIs. Density of incidence of BSI, VAP and UTI was 18.1, 7.9 and 5.1/1000 days of use of CVC, ETT and UC respectively. BSI was more common in children with CVCs than in those without CVCs (20% <it>vs</it>. 4.7%, p < 0.05). <it>Candida </it>spp. was the commonest microorganism in BSI (41%), followed by Coagulase-negative <it>Staphylococcus </it>(17%). <it>Pseudomonas </it>(52%) was the most common germ for VAP and <it>Candida </it>(71%) for UTI. The presence of NI was associated with increased mortality (38.2% <it>vs</it>. 20.4% in children without NI; p < 0.001) and the median length of ICU stay (23 <it>vs</it>. 6 days in children without NI; p < 0.001). Children with NI had longer average hospital stay previous to diagnosis of this condition (12.3 <it>vs</it>. 6 days; p < 0.001).</p> <p>Conclusions</p> <p>One of every 5 children acquires an NI in the PICU. Its presence was associated with increased mortality and length of stay. At the same time a longer stay was associated with an increased risk of developing NI.</p

Electromagnetic Assessment of UHF-RFID Devices in Healthcare Environment

In this work, the evaluation of electromagnetic effect of Ultra High Frequency Radio Frequency Identification (UHF-RFID) passive tags used in the healthcare environment is presented. In order to evaluate exposure levels caused by EM field (865–868 MHz) of UHF-RFID readers, EM measurements in an anechoic chamber and in a real medical environment (Hospital Universitario de Canarias), as well as simulations by 3D Ray Launching algorithm, and of biophysical exposure effects in human models are presented. The results obtained show that the EM exposure is localized, in close vicinity of RFID reader and inversely proportional to its reading range. The EM exposure levels detected are sufficient to cause EM immunity effects in electronic devices (malfunctions in medical equipment or implants). Moreover, more than negligible direct effects in humans (exceeding relevant SAR values) were found only next to the reader, up to approximately 30% of the reading range. As a consequence, the EM risk could be firstly evaluated based on RFID parameters, but should include an in situ exposure assessment. It requires attention and additional studies, as increased applications of monitoring systems are observed in the healthcare sector—specifically when any system is located close to the workplace that is permanently occupied.This work was supported by Instituto de Salud Carlos III project “Electromagnetic “Characterization in Smart Environments of Healthcare, and their involvement in Personal, Occupational, and Environmental Health” (PI14CIII/00056) https://portalfis.isciii.es/es/Paginas/DetalleProyecto. aspx?idProyecto=PI14CIII%2f00056 (accessed on 24 July 2022), and project “ (PI19CIII/00033) TMPY 508/19 “ Metrics development for electromagnetic safety assessment in healthcare centers in the context of 5G“ https://portalfis.isciii.es/es/Paginas/DetalleProyecto.aspx?idProyecto=PI19 CIII%2f00033, (accessed on 24 July 2022) from Sub-Directorate-General for Research Assessment and Promotion. The results of a research task (II.PB.15) carried out within the National Programme “Improvement of safety and working conditions” partly supported in Poland in 2020-2022-within the scope of research and development-by the National Centre for Research and Development were also included.S

Low variability of single-molecule conductance assisted by bulky metal-molecule contacts

A detailed study of the trimethylsilylethynyl moiety, –C[triple bond]CSiMe3 (TMSE) , as an anchoring group in metalmoleculemetal junctions, using a combination of experiment and density functional theory is presented. It is shown that the TMSE anchoring group provides improved control over the molecule-substrate arrangement within metalmoleculemetal junctions, with the steric bulk of the methyl groups limiting the number of highly transmissive binding sites at the electrode surface, resulting in a single sharp peak in the conductance histograms recorded by both the in situ break junction and I(s) STM techniques. As a consequence of the low accessibility of the TMSE group to surface binding configurations of measurable conductance, only about 10% of gold break junction formation cycles result in the clear formation of molecular junctions in the experimental histograms. The DFT-computed transmission characteristics of junctions formed from the TMSE-contacted oligo(phenylene)ethynylene (OPE)-based molecules described here are dominated by tunneling effects through the highest-occupied molecular orbitals (HOMOs). This gives rise to similar conductance characteristics in these TMSE-contacted systems as found in low conductance-type junctions based on comparably structured OPE-derivatives with amine-contacts that also conduct through HOMO-based channels.R. R. F. thanks the Consejería de Educación del Principado de Asturias for a Severo Ochoa grant (BP11-069). V. M. G.-S. thanks the Spanish Ministerio de Economía y Competitividad for a Ramón y Cajal fellowship (RYC-2010-06053). R. R. F., J. F. and V. M. G.-S. wish to acknowledge financial support from the Spanish grant FIS2012-34858 and the Marie Curie Network MOLESCO. P. C. and S. M. are grateful for financial assistance from the Ministerio de Economía y Competitividad of Spain in the framework of the project CTQ2012-33198 as well as the award of the CTQ2013-50187-EXP grant. H. M. O., P. C., and S. M. thank the support from DGA and Fondos FEDER for funding through the Platon research group. H. M. O. is also grateful for financial assistance from the Secretaría Nacional de Educación Superior, Ciencia, Tecnología e Innovaciín from Ministerio de Educación (Ecuador). S. M. thanks the Ministerio de Educación from Spain for financial support through the framework of the Campus de Excelencia Internacional, CEI Iberus. S. J. H., R. J. N., P. J. L. and S. M.-G. thank the EPSRC for funding (EPSRC grants EP/K007785/1, EP/H035184/1, EP/K007548/1, EP/H005595/1). P. J. L. holds an Australian Research Council Future Fellowship (FT120100073) and gratefully acknowledges funding for this work from the ARC (DP140100855).Peer Reviewe

Follow-up care over 12months of patients with prostate cancer in Spain A multicenter prospective cohort study

The therapeutic approach is crucial to prostate cancer prognosis. We describe treatments and outcomes for a Spanish cohort of patients with prostate cancer during the first 12 months after diagnosis and identify the factors that influenced the treatment they received. This multicenter prospective cohort study included patients with prostate cancer followed up for 12 months after diagnosis. Treatment was stratified by factors such as hospital, age group (<70 and ≥70 years), and D'Amico cancer risk classification. The outcomes were Eastern Cooperative Oncology Group (ECOG) performance status, adverse events (AEs), and mortality. The patient characteristics associated with the different treatment modalities were analyzed using multivariate logistic regression. We included 470 men from 7 Spanish tertiary hospitals (mean (standard deviation) age 67.8 (7.6) years), 373 (79.4%) of which received treatment (alone or in combination) as follows: surgery (n = 163; 34.7%); radiotherapy (RT) (n = 149; 31.7%); and hormone therapy (HT) (n = 142; 30.2%). The remaining patients (n = 97) were allocated to no treatment, that is, watchful waiting (14.0%) or active surveillance (5.7%). HT was the most frequently administered treatment during follow-up and RT plus HT was the most common therapeutic combination. Surgery was more frequent in patients aged <70, with lower histologic tumor grades, Gleason scores <7, and lower prostate-specific antigen levels; while RT was more frequent in patients aged ≥70 with histologic tumor grade 4, and higher ECOG scores. HT was more frequent in patients aged ≥70, with histologic tumor grades 3 to 4, Gleason score ≥8, ECOG ≥1, and higher prostate-specific antigen levels. The number of fully active patients (ECOG score 0) decreased significantly during follow-up, from 75.3% at diagnosis to 65.1% at 12 months (P <.001); 230 (48.9%) patients had at least 1 AE, and 12 (2.6%) patients died. Surgery or RT were the main curative options. A fifth of the patients received no treatment. Palliative HT was more frequently administered to older patients with higher tumor grades and higher Gleason scores. Close to half of the patients experienced an AE related to their treatment

Reflexiones sobre los retos y oportunidades de la educación híbrida

3er Coloquio Fortalecimiento de los Colectivos de Docencia.Reconociendo que esta educación tiene características y metodologías pedagógicas diferentes a las presenciales, de cara al futuro hay que pensar en un formato híbrido que combine la noción presencial y la noción virtual de manera funcional. La modalidad actual funciona como respuesta a una emergencia, pero hay que desarrollar estrategias que sostengan este nuevo modelo en el mediano plazo. Integrantes del Colectivo de Docencia de Diseño Industrial del Departamento de Evaluación, nos reunimos en conferencia vía zoom, para discurrir sobre el tema. Algunas de las reflexiones se integran a la presentación en forma directa con el fin de evitar cualquier mala interpretación relacionada a las propuestas y sugerencias

IAA : Información y actualidad astronómica (25)

Sumario : La química del Universo y el origen de la vida.-- Vida humana en el espacio.-- HISTORIAS DE ASTRONOMÍA: Desmenuzando la materia.-- Examen final al Modelo Estándar de Partículas.-- CIENCIA: PILARES E INCERTIDUMBRES : Evolución del análisis armónico.-- DECONSTRUCCIÓN Y otros ENSAYOS : Las distintas escalas de un agujero negro.-- ACTUALIDAD.-- ENTRE BASTIDORES.-- ACTIVIDADES IAA .Esta revista se publica con la ayuda FCT-08-0130 del Programa Nacional de Fomento de la Cultura Científica y Tecnológica 2008.N

Aerosol concentration at two heights (2550 and 650 m a.s.l.) in SE Spain

Ponencia presentada en: XXXV Jornadas Científicas de la AME y el XIX Encuentro Hispano Luso de Meteorología celebrado en León, del 5 al 7 de marzo de 2018.The simultaneous aerosol sampling at two heights in southern Spain may provide valuable information on the vertical structure of the dust transport from North Africa to the Iberian Peninsula. It also allows the characterization of the ambient air at two sites with distinct anthropogenic impact. This work presents the results obtained from the first field campaign of the FRESA project (Impact of dust-laden African air masses and of stratospheric air masses in the Iberian Peninsula. Role of the Atlas Mountains), performed in the period July-November 2017 at El Albergue Universitario in Sierra Nevada (2550 m a.s.l.) and the city of Granada (650 m a.s.l.). The two sites were instrumented with a low-volume sampler with PM10 inlet for daily sampling and mass and chemical composition characterization, a high-volume sampler for total suspended particles (TSP) for weekly sampling and radionuclide activity determination, and with a GRIMM 365 optical particle counter that provides continuously the aerosol size distribution