Insulator-to-metal transition in vanadium supersaturated silicon: variable-range hopping and Kondo effect signatures

We report the observation of the insulator-to-metal transition in crystalline silicon samples supersaturated with vanadium. Ion implantation followed by pulsed laser melting and rapid resolidification produce high quality single-crystalline silicon samples with vanadium concentrations that exceed equilibrium values in more than 5 orders of magnitude. Temperature-dependent analysis of the conductivity and Hall mobility values for temperatures from 10K to 300K indicate that a transition from an insulating to a metallic phase is obtained at a vanadium concentration between 1.1 × 10^(20) and 1.3 × 10^(21) cm^(−3) . Samples in the insulating phase present a variable-range hopping transport mechanism with a Coulomb gap at the Fermi energy level. Electron wave function localization length increases from 61 to 82 nm as the vanadium concentration increases in the films, supporting the theory of impurity band merging from delocalization of levels states. On the metallic phase, electronic transport present a dispersion mechanism related with the Kondo effect, suggesting the presence of local magnetic moments in the vanadium supersaturated silicon material

Vertical Jumping as a Monitoring Tool in Endurance Runners: A Brief Review

[EN] umping performance (e.g., countermovement jump [CMJ]), as a measure of neuromuscular performance, has been suggested as an easy-to-use tool which simultaneously provides neuromuscular and metabolic information and, thereby, allows coaches to confidently monitor the status of their athletes during a workout. This hypothesis has been satisfactorily tested with sprint athletes. However, the rationale for the use of CMJ height loss as an index to monitor the workload during an endurance running session is not sufficiently evidence-based. First, it is assumed that a CMJ height loss occurs during typical interval training for endurance runners. Second, it is also assumed that a significant relationship between metabolic stress and the neuromuscular strain induced during these endurance workouts exists. These two assumptions will be questioned in this review by critically analyzing the kinetics of CMJ performance during and after running workouts, and the relationship between neuromuscular and physiological stress induced during different protocols in endurance runners. The current evidence shows that fatigue induced by common running workouts for endurance runners does not counterbalance the potentiation effect in the CMJ height. Additionally, the findings reported among different studies are consistent regarding the lack of association between CMJ height loss and physiological stress during interval sessions in endurance runners. In practical terms, the authors suggest that this marker of neuromuscular fatigue may not be used to regulate the external training load during running workouts in endurance runners. Nevertheless, the analysis of CMJ height during running workouts may serve to monitor chronic adaptations to training in endurance runners

Prediction of bronchopulmonary dysplasia in very preterm infants: competitive risk model nomogram

[Abstract] Objective: To develop predictive clinical models of bronchopulmonary dysplasia (BPD) through competing risk analysis. Methods: Retrospective observational cohort study, including preterm newborns ≤32 weeks gestational age, conducted between January 1, 2013 and September 30, 2022 in a third-level Neonatal Intensive Care Unit in Spain. A prediction study was carried out using competing risk models, where the event of interest was BPD and the competing event was death. A multivariate competing risk model was developed separately for each postnatal day (days 1, 3, 7 and 14). Nomograms to predict BPD risk were developed from the coefficients of the final models and internally validated. Results: A total of 306 patients were included in the study, of which 73 (23.9%) developed BPD and 29 (9.5%) died. On day 1, the model with the greatest predictive capacity was that including birth weight, days since rupture of membranes, and surfactant requirement (area under the receiver operating characteristic (ROC) curve (AUC), 0.896; 95% CI, 0.792–0.999). On day 3, the final predictive model was based on the variables birth weight, surfactant requirement, and Fraction of Inspired Oxygen (FiO2) (AUC, 0.891; 95% CI, 0.792–0.989). Conclusions: Competing risk analysis allowed accurate prediction of BPD, avoiding the potential bias resulting from the exclusion of deceased newborns or the use of combined outcomes. The resulting models are based on clinical variables measured at bedside during the first 3 days of life, can be easily implemented in clinical practice, and can enable earlier identification of patients at high risk of BPD.info:eu-repo/grantAgreement/ISCIII/Programa Estatal de Generación de Conocimiento y Fortalecimiento del Sistema Español de I+D+I/PI21%2F01601/ES/HAPLOGRUPOS DE ADN MITOCONDRIAL Y NIVELES DE ADN MITOCONDRIAL CIRCULANTES EN PACIENTES GRANDES PREMATUROS CON DISPLASIA BRONCOPULMONA

Nasal intermittent positive pressure ventilation and bronchopulmonary dysplasia among very preterm infants never intubated during the first neonatal admission: a multicenter cohort study

[Abstract] Introduction: While non-invasive positive-pressure ventilation (NIPPV) is increasingly used as a mode of respiratory support for preterm infants, it remains unclear whether this technique translates into improved respiratory outcomes. We assessed the association between NIPPV use and bronchopulmonary dysplasia (BPD)-free survival in never intubated very preterm infants. Methods: This multicenter cohort study analyzed data from the Spanish Neonatal Network SEN1500 corresponding to preterm infants born at <32 weeks gestational age and <1,500 g and not intubated during first admission. The exposure of interest was use of NIPPV at any time and the main study outcome was survival without moderate-to-severe BPD. Analyses were performed both by patients and by units. Primary and secondary outcomes were compared using multilevel logistic-regression models. The standardized observed-to-expected (O/E) ratio was calculated to classify units by NIPPV utilization and outcome rates were compared among groups. Results: Of the 6,735 infants included, 1,776 (26.4%) received NIPPV during admission and 6,441 (95.6%) survived without moderate-to-severe BPD. After adjusting for confounding variables, NIPPV was not associated with survival without moderate-to-severe BPD (OR 0.84; 95%CI 0.62–1.14). A higher incidence of moderate-to-severe BPD-free survival was observed in high- vs. very low-utilization units, but no consistent association was observed between O/E ratio and either primary or secondary outcomes. Conclusion: NIPPV use did not appear to decisively influence the incidence of survival without moderate-to-severe BPD in patients managed exclusively with non-invasive ventilation

Los discos de oro del Museo Arqueológico de Asturias: algunas observaciones sobre la orfebrería prehistórica

Se presenta un estudio detallado de dos discos de oro de procedencia desconocida que permanecen depositados desde mediados del s. xx en el Museo Arqueológico de Asturias. Pese a la abundante bibliografía sobre estas piezas, hasta el momento no se había realizado un análisis arqueométrico y arqueometalúrgico de las mismas. Los resultados permiten inferir observaciones interesantes acerca de su composición, manufactura y secuencia tecnológica de elaboración, así como sobre la posible procedencia del oro, confirmando, con los paralelos reconocidos para la decoración de estas placas, de una clara raigambre atlántica.Los ejemplares de las Islas Británicas se asocian con inhumaciones campaniformes. Para los objetos en estudio se consideró una cronología más moderna dada la ausencia de evidencias similares en Asturias. Sin embargo, la reciente identificación de las típicas cerámicas en espacios de transformación de mineral de cobre en el territorio central asturiano posibilita una nueva consideración, reforzada con los más recientes hallazgos áureos de similar cronología en la Península Ibérica que se reconocen como parte del ajuar de inhumaciones campaniformes. Todos los argumentos refuerzan la propuesta de la existencia de redes de intercambio entre las Islas Británicas y el continente a lo largo de aquel periodo

Circumcision Clamps for Adults

Circumcision is one of the surgical interventions with the longest historical tradition for various medical or non-medical, religious and social, reasons. Due to a high demand for this surgery, in recent years, a large number of plastic and disposable devices have emerged in order to optimize the technique. Although they were initially used in newborns and children, their use in recent years has been expanding to adults. The main objectives of these devices are to shorten the surgical time, simplify the technique, and maintain an adequate safety profile compared to the classic suture technique. All reviewed devices for adult circumcision appear to achieve these goals, making them a safe, fast, and feasible option for use in an outpatient setting or in high-demand areas

Early neglect associated to prefrontal structural disconnectivity in schizophrenia

[ES] Negligencia y descuido temprano asociado a la desconexión estructural prefrontal en la esquizofrenia