Epidemiology of pediatric spinal trauma with neurological deficits in Catalonia: a 36-year experience.

PURPOSE: Existing literature on pediatric traumatic spinal cord injury (PTSCI) demonstrates large variations in characteristics, incidence, time-periods and etiology, worldwide. Epidemiological studies addressing injuries to the total spine, conducted in Southern European regions are remarkably scarce; therefore we aimed to investigate long-term trends analyzing etiology, fracture location and type, single or multiple fractures, associated lesions and neurological status in Catalonia, Spain. METHODS: We conducted a retrospective observational study. We analyzed post-acute patients after PTSCI, aged 0-17, admitted with neurological deficits between 1986 and 2022 to a specialized hospital in Catalonia. Neurological deficits were assessed using the American Spinal Injury Association Impairment Scale (AIS). RESULTS: Two hundred and forty nine children were included, 174 (69.9%) boys and 75 (30.1%) girls; mean age was 13.9 years (range, 2 months to 17 years). Two hundred and four children (82%) had ≥ 1 spinal fractures, 66 (26.5%) dislocations and 8 (3.2%) SCIWORA. Fractures were multilevel contiguous in 108 (43.4%) cases. Fracture types comprised 81 vertebral compactions (32.5%), 22 burst fractures (8.8%), 7 odontoid (2.8%) and 4 tear-drops (1.6%). There were ≥ 1 associated lesions in 112 cases (45%): in limbs in 23 cases (9.2%), thorax or abdomen in 59 (23.7%) and skull or face in 81 (32.5%). In 44 cases (39% of the 112) there were multiple lesions. Locations comprised cervical spine in 105 cases (42%), thoracic spine in 124 (49%), lumbar spine in 18 (7%), and sacrum in 2 (0.8%). Road traffic accidents (RTAs) were the main etiology (62.2%) over the whole period. However, from 2016 onwards, RTAs dropped below the rate of falls and sports injuries. The most common sites for injury in those aged 9 years or older were in the cervical (41.1%) and thoracic (50.7%) regions. Those aged 8 or under were far more likely to sustain a complete SCI (80.0%) or an accompanying traumatic brain injury (45.0%) likely due to higher numbers of pedestrian versus car RTAs. A significant peak in the occurrence of cases during 2006-2010 (20.1%) was identified with an absolute drop immediately after, during 2011-2015 (8.8%). A marked shift in trend is observed between 2016-2022 regarding age of injuries (an increase in 9 years or older), etiology (increase in falls and sports versus RTA), AIS grade (increase in incomplete lesions AIS B-D versus AIS A), severity (increase in tetraplegia versus paraplegia) and location (increase in cervical versus lumbar and thoracic injuries). CONCLUSIONS: A shift in trend is observed in the past 7 years regarding age of injuries (increase in those older than 9), etiology (increase in falls and sports versus RTA), AIS grade (increase in incomplete lesions AIS B-D versus AIS A), severity (increase in tetraplegia versus paraplegia) and location (increase in cervical). LEVEL OF EVIDENCE: IV.

Calorie Restriction and Time-Restricted Feeding: Effective Interventions in Overweight or Obese Patients Undergoing Radiotherapy Treatment with Curative Intent for Cancer.

This study assesses the feasibility of calorie restriction (CR) and time-restricted feeding (TRF) in overweight and obese cancer patients who realized little to no physical activity undergoing curative radiotherapy, structured as a prospective, interventional, non-randomized open-label clinical trial. Of the 27 participants initially enrolled, 21 patients with breast cancer were selected for analysis. The participants self-selected into two dietary interventions: TRF, comprising a sugar and saturated fat-free diet calibrated to individual energy needs consumed within an 8 h eating window followed by a 16 h fast, or CR, involving a 25% reduction in total caloric intake from energy expenditure distributed across 4 meals and 1 snack with 55% carbohydrates, 15% protein, and 30% fats, excluding sugars and saturated fats. The primary goal was to evaluate the feasibility of these diets in the specific patient group. The results indicate that both interventions are effective and statistically significant for weight loss and reducing one's waist circumference, with TRF showing a potentially stronger impact and better adherence. Changes in the LDL, HDL, total cholesterol, triglycerides, glucose and insulin were not statistically significant.

A robust deep learning detector for sleep spindles and K-complexes: towards population norms.

Sleep spindles (SSs) and K-complexes (KCs) are brain patterns involved in cognitive functions that appear during sleep. Large-scale sleep studies would benefit from precise and robust automatic sleep event detectors, capable of adapting the variability in both electroencephalography (EEG) signals and expert annotation rules. We introduce the Sleep EEG Event Detector (SEED), a deep learning system that outperforms existing approaches in SS and KC detection, reaching an F1-score of 80.5% and 83.7%, respectively, on the MASS2 dataset. SEED transfers well and requires minimal fine-tuning for new datasets and annotation styles. Remarkably, SEED substantially reduces the required amount of annotated data by using a novel pretraining approach that leverages the rule-based detector A7. An analysis of 11,224 subjects revealed that SEED's detections provide better estimates of SS population statistics than existing approaches. SEED is a powerful resource for obtaining sleep-event statistics that could be useful for establishing population norms.

Chemistry and microstructure of C-supported Ru catalyst nanoparticles: A correlative study.

Ru@Pt core shell nanoparticles possess optimal catalytic properties that facilitate the anodic oxidation reaction of H2 with decreased Pt loading in hydrogen fuel cells. Moreover, since they preferentially oxidize CO, Pt poisoning is considerably reduced, which significantly improves the stability of the cell. The Ru cores used in this system are usually synthesized by dissolving a RuCl3*H2O precursor in an ethylene glycol-carbon black-NaOH mixture. However, the possibility that remnant Cl and Na from the synthesis process are present in the Ru nanoparticles has not been extensively studied. Therefore, due to the challenges in detecting impurities with traditional characterization methods, here correlative atom probe tomography (APT) with scanning transmission electron microscopy ((S)TEM) techniques were implemented. The capabilities of APT to obtain chemical information with high sensitivity at the nanoscale, in combination with the high spatial resolving power of (S)TEM, provide the necessary resolution to fully characterize the structure and chemical makeup of Ru nanoparticles.

Insights into the performance and degradation of Ru@Pt core-shell catalysts for fuel cells by advanced (scanning) transmission electron microscopy.

Ru@Pt core-shell nanoparticles are currently being explored as carbon monoxide tolerant anode catalysts for proton exchange membrane fuel cells. However, little is known about their degradation under fuel cell conditions. In the present work, two types of Ru@Pt nanoparticles with nominal shell thicknesses of 1 (Ru@1Pt) and 2 (Ru@2Pt) Pt monolayers are studied as synthesized and after accelerated stress tests. These stress tests were designed to imitate the degradation occurring under fuel cell operating conditions. Our advanced (scanning) transmission electron microscopy characterization explains the superior initial electrochemical performance of Ru@1Pt. Moreover, the 3D reconstruction of the Pt shell by electron tomography reveals an incomplete shell for both samples, which results in a less stable Ru metal being exposed to an electrolyte. The degree of coverage of the Ru cores provides insights into the higher stability of Ru@2Pt during the accelerated stress tests. Our results explain how to maximize the initial performance of Ru@Pt-type catalysts, without compromising their stability under fuel cell conditions.

Evaluation of functional layers thinning of high temperature polymer electrolyte membrane fuel cells after long term operation.

The operation related degradation processes of high temperature polymer electrolyte membrane fuel cell operated with hydrogen-rich reformate gas are studied. CO impurities from the reformate gas are strongly adsorbed by the catalyst surface, leading to poisoning and thus, reduction of the overall performance of the cell. Most of the studies are performed in a laboratory set-up by applying accelerated stress tests. In the present work, a high temperature polymer electrolyte membrane fuel cell is operated in a realistic configuration for 12 000 h (500 days). The fuel cell contains as electrocatalyst Pt in the cathode and a Pt-Ru alloy in the anode. The study of the degradation occurring in the functional layers, i.e. in different regions of cathode, anode and membrane layer, is carried out by scanning electron microscopy, (scanning) transmission electron microscopy and energy dispersive X-ray spectroscopy. We observed a thinning of the functional layers and a redistribution of catalyst material. The thinning of the cathode side is larger compared to the anode side due to harsher operation conditions likely causing a degradation of the support material via C corrosion and/or due to a degradation of the catalyst via oxidation of Pt and Ru. A thinning of the membrane caused by oxidation agents is also detected. Moreover, during operation, catalyst material is dissolved at the cathode side and redistributed. Our results will help to design and develop fuel cells with higher performance.

Going deep into schizophrenia with artificial intelligence.

Despite years of research, the mechanisms governing the onset, relapse, symptomatology, and treatment of schizophrenia (SZ) remain elusive. The lack of appropriate analytic tools to deal with the heterogeneity and complexity of SZ may be one of the reasons behind this situation. Deep learning, a subfield of artificial intelligence (AI) inspired by the nervous system, has recently provided an accessible way of modeling and analyzing complex, high-dimensional, nonlinear systems. The unprecedented accuracy of deep learning algorithms in classification and prediction tasks has revolutionized a wide range of scientific fields and is rapidly permeating SZ research. Deep learning has the potential of becoming a valuable aid for clinicians in the prediction, diagnosis, and treatment of SZ, especially in combination with principles from Bayesian statistics. Furthermore, deep learning could become a powerful tool for uncovering the mechanisms underlying SZ thanks to a growing number of techniques designed for improving model interpretability and causal reasoning. The purpose of this article is to introduce SZ researchers to the field of deep learning and review its latest applications in SZ research. In general, existing studies have yielded impressive results in classification and outcome prediction tasks. However, methodological concerns related to the assessment of model performance in several studies, the widespread use of small training datasets, and the little clinical value of some models suggest that some of these results should be taken with caution.

A plastic feedthrough suitable for high-voltage DC femtosecond electron diffractometers.

Highly energetic ultrashort electron bunches have the potential to reveal the ultrafast structural dynamics in relatively thicker in-liquid samples. However, direct current voltages higher than 100 kV are exponentially difficult to attain as surface and vacuum breakdown become an important problem as the electric field increases. One of the most demanding components in the design of a high-energy electrostatic ultrafast electron source is the high voltage feedthrough (HVFT), which must keep the electron gun from discharging against ground. Electrical discharges can cause irreversible component damage, while voltage instabilities render the instrument inoperative. We report the design, manufacturing, and conditioning process for a new HVFT that utilizes ultra-high molecular weight polyethylene as the insulating material. Our HVFT is highly customizable and inexpensive and has proven to be effective in high voltage applications. After a couple of weeks of gas and voltage conditioning, we achieved a maximum voltage of 180 kV with a progressively improved vacuum level of 1.8 × 10-8 Torr.

Fish predation hinders the success of coral restoration efforts using fragmented massive corals.

As coral reefs continue to decline globally, coral restoration practitioners have explored various approaches to return coral cover and diversity to decimated reefs. While branching coral species have long been the focus of restoration efforts, the recent development of the microfragmentation coral propagation technique has made it possible to incorporate massive coral species into restoration efforts. Microfragmentation (i.e., the process of cutting large donor colonies into small fragments that grow fast) has yielded promising early results. Still, best practices for outplanting fragmented corals of massive morphologies are continuing to be developed and modified to maximize survivorship. Here, we compared outplant success among four species of massive corals (Orbicella faveolata, Montastraea cavernosa, Pseudodiploria clivosa, and P. strigosa) in Southeast Florida, US. Within the first week following coral deployment, predation impacts by fish on the small (<5 cm2) outplanted colonies resulted in both the complete removal of colonies and significant tissue damage, as evidenced by bite marks. In our study, 8-27% of fragments from four species were removed by fish within one week, with removal rates slowing down over time. Of the corals that remained after one week, over 9% showed signs of fish predation. Our findings showed that predation by corallivorous fish taxa like butterflyfishes (Chaetodontidae), parrotfishes (Scaridae), and damselfishes (Pomacentridae) is a major threat to coral outplants, and that susceptibility varied significantly among coral species and outplanting method. Moreover, we identify factors that reduce predation impacts such as: (1) using cement instead of glue to attach corals, (2) elevating fragments off the substrate, and (3) limiting the amount of skeleton exposed at the time of outplanting. These strategies are essential to maximizing the efficiency of outplanting techniques and enhancing the impact of reef restoration.

Cryo-focused ion beam preparation of perovskite based solar cells for atom probe tomography.

Focused-ion beam lift-out and annular milling is the most common method used for obtaining site specific specimens for atom probe tomography (APT) experiments and transmission electron microscopy. However, one of the main limitations of this technique comes from the structural damage as well as chemical degradation caused by the beam of high-energy ions. These aspects are especially critical in highly-sensitive specimens. In this regard, ion beam milling under cryogenic conditions has been an established technique for damage mitigation. Here, we implement a cryo-focused ion beam approach to prepare specimens for APT measurements from a quadruple cation perovskite-based solar cell device with 19.7% efficiency. As opposed to room temperature FIB milling we found that cryo-milling considerably improved APT results in terms of yield and composition measurement, i.e. halide loss, both related to less defects within the APT specimen. Based on our approach we discuss the prospects of reliable atom probe measurements of perovskite based solar cell materials. An insight into the field evaporation behavior of the organic-inorganic molecules that compose the perovskite material is also given with the aim of expanding the applicability of APT experiments towards nano-characterization of complex organo-metal materials.

Trapping a Photoelectron behind a Repulsive Coulomb Barrier in Solution.

Multiply charged anions (MCAs) display unique photophysics and solvent-stabilizing effects. Well-known aqueous species such as SO42- and PO43- experience spontaneous electron detachment or charge-separation fragmentation in the gas phase owing to the strong Coulomb repulsion arising from the excess of negative charge. Thus, anions often present low photodetachment thresholds and the ability to quickly eject electrons into the solvent via charge-transfer-to-solvent (CTTS) states. Here, we report spectroscopic evidence for the existence of a repulsive Coulomb barrier (RCB) that blocks the ejection of "CTTS-like" electrons of the aqueous B12F122- dianion. Our spectroscopic experimental and theoretical studies indicate that despite the exerted Coulomb repulsion by the nascent radical monoanion B12F12-•aq, the photoexcited electron remains about the B12F12-• core. The RCB is an established feature of the potential energy landscape of MCAs in vacuo, which seems to extend to the liquid phase highlighting recent observations about the dielectric behavior of confined water.

Static and dynamic scavenging of ammoniated electrons by nitromethane.

We studied the time-resolved scavenging efficiency of nitromethane for transient electron species in liquid ammonia, at a temperature of 298 K. UV excitation of iodide ions produced fully solvated electrons, as well as transient (I, e-) and (counterion, e-) pairs, the overall concentration of which was monitored by NIR absorption with subpicosecond time resolution. After the UV pulse, the solution absorbance decays almost completely in a few hundreds of picoseconds due to geminate electron-iodine atom recombination and a competitive annihilation channel involving the scavenger. Recombination of transient (I, e-) pairs follows the well-known kinetic model, while the electron-nitromethane reaction proceeds by two distinct mechanisms: static scavenging (interpreted in terms of the encounter complex model), with a characteristic time shorter than the temporal resolution of the apparatus, or via a diffusion-limited bimolecular reaction, with a rate constant of 1.1 × 1011 M-1 s-1.

High flow rate nanofluidics for in-liquid electron microscopy and diffraction.

We introduce a nanofluidic platform that can be used to carry out femtosecond electron diffraction (FED) and transmission electron microscopy (TEM) measurements in liquid samples or in-liquid specimens, respectively. The nanofluidic cell (NFC) system presented herein has been designed to withstand high sample refreshing rates (over one kilohertz), a prerequisite to succeed with FED experiments in our lab. Short beam paths, below 1 µm, in combination with ultrathin membranes (less than 100 nm thick) are necessary conditions for in-liquid FED and TEM studies due to the strongly interacting nature of electrons. Depending on the application, the beam path in our NFC can be tuned between 50 nm and 10 µm with ultrathin stoichiometric silicon nitride (Si3N4) windows as thin as 20 nm. Stoichiometric Si3N4 has been selected to reduce membrane bulging owing to its higher tensile stress and transparency in the UV-vis-NIR region to allow for laser excitation in FED experiments. Key design parameters and improvements made over previous NFC systems are discussed, and some preliminary electron images obtained by 200 kV scanning TEM are presented.

How antagonistic salts cause nematic ordering and behave like diblock copolymers.

We present simulation results and an explanatory theory on how antagonistic salts affect the spinodal decomposition of binary fluid mixtures. We find that spinodal decomposition is arrested and complex structures form only when electrostatic ion-ion interactions are small. In this case, the fluid and ion concentrations couple and the charge field can be approximated as a polynomial function of the relative fluid concentrations alone. When the solvation energy associated with transferring an ion from one fluid phase to the other is of the order of a few kBT, the coupled fluid and charge fields evolve according to the Ohta-Kawasaki free energy functional. This allows us to accurately predict structure sizes and reduce the parameter space to two dimensionless numbers. The lamellar structures induced by the presence of the antagonistic salt in our simulations exhibit a high degree of nematic ordering and the growth of ordered domains over time follows a power law. This power law carries a time exponent proportional to the salt concentration. We qualitatively reproduce and interpret neutron scattering data from previous experiments of similar systems. The dissolution of structures at high salt concentrations observed in these experiments agrees with our simulations, and we explain it as the result of a vanishing surface tension due to electrostatic contributions. We conclude by presenting 3D results showing the same morphologies as predicted by the Ohta-Kawasaki model as a function of volume fraction and suggesting that our findings from 2D systems remain valid in 3D.

Experiments and characterization of low-frequency oscillations in a granular column.

The behavior of a vertically vibrated granular bed is reminiscent of a liquid in that it exhibits many phenomena such as convection and Faraday-like surface waves. However, when the lateral dimensions of the bed are confined such that a quasi-one-dimensional geometry is formed, the only phenomena that remain are bouncing bed and the granular Leidenfrost effect. This permits the observation of the granular Leidenfrost state for a wide range of energy injection parameters and more specifically allows for a thorough characterization of the low-frequency oscillation (LFO) that is present in this state. In both experiments and particle simulations we determine the LFO frequency from the power spectral density of the center-of-mass signal of the grains, varying the amplitude and frequency of the driving, the particle diameter, and the number of layers in the system. We thus find that the LFO frequency (i) is inversely proportional to the fast inertial timescale and (ii) decorrelates with a typical decay time proportional to the slow dissipative timescale in the system. The latter is consistent with the view that the LFO is driven by the inherent noise that is present in the granular Leidenfrost state with a low number of particles.

Mesoscopic electrohydrodynamic simulations of binary colloidal suspensions.

A model is presented for the solution of electrokinetic phenomena of colloidal suspensions in fluid mixtures. We solve the discrete Boltzmann equation with a Bhatnagar-Gross-Krook collision operator using the lattice Boltzmann method to simulate binary fluid flows. Solvent-solvent and solvent-solute interactions are implemented using a pseudopotential model. The Nernst-Planck equation, describing the kinetics of dissolved ion species, is solved using a finite difference discretization based on the link-flux method. The colloids are resolved on the lattice and coupled to the hydrodynamics and electrokinetics through appropriate boundary conditions. We present the first full integration of these three elements. The model is validated by comparing with known analytic solutions of ionic distributions at fluid interfaces, dielectric droplet deformations, and the electrophoretic mobility of colloidal suspensions. Its possibilities are explored by considering various physical systems, such as breakup of charged and neutral droplets and colloidal dynamics at either planar or spherical fluid interfaces.

Phase-coexisting patterns, horizontal segregation, and controlled convection in vertically vibrated binary granular mixtures.

We report patterns consisting of coexistence of synchronous and asynchronous states [for example, a granular gas co-existing with (i) bouncing bed, (ii) undulatory subharmonic waves, and (iii) Leidenfrost-like states] in experiments on vertically vibrated binary granular mixtures in a Hele-Shaw cell. Most experiments have been carried out with equimolar binary mixtures of glass and steel balls of same diameter by varying the total layer height (F) for a range of shaking acceleration (Γ). All patterns as well as the related phase diagram in the (Γ,F) plane have been reproduced via molecular dynamics simulations of the same system. The segregation of heavier and lighter particles along the horizontal direction is shown to be the progenitor of such phase-coexisting patterns as confirmed in both experiment and simulation. At strong shaking we uncover a partial convection state in which a pair of convection rolls is found to coexist with a Leidenfrost-like state. The crucial role of the relative number density of two species on controlling the buoyancy-driven granular convection is demonstrated. The onset of horizontal segregation can be explained in terms of an anisotropic diffusion tensor.

Necesidades educativas especiales y educación física: las actividades en la naturaleza como instrumento socializador / Special educatives needs and physical education: the activities in the nature as socialized instrument

El escrito que se presenta a continuación es el resultado de un trabajo indagativo relacionado con las actividades en contacto con la naturaleza (ACN) y personas con necesidades educativas especiales (NEE). El objetivo de este estudio ha sido identificar la influencia que este tipo de actividades ejerce sobre los estudiantes con NEE y de qué forma afecta su entorno cercano y las relaciones sociales que sostiene en su diario vivir. La investigación se enmarca en la metodología cualitativa toda vez que lo central es conocer el sentido que se le otorga a esta línea de trabajo desde la perspectiva de la actividad física. Los resultados permiten concluir que el acercamiento y relación de los estudiantes con NEE a los espacios naturales tiene una influencia positiva y colabora asimismo en su autoconocimiento, autoestima, mejora de las relaciones sociales, con su entorno y familia.

The article that follows is the result of a investigative work related outdoor activities and people with special educatives needs (SEN). The aim of this study was to identify the influence that these activities have on students with SEN and how it affects their immediate environment and social relations holding. The research is part of the qualitative methodology given that the core is known the sense that gives this line of work from the perspective of physical activity. Results show that the approach and relationship of students with SEN to natural areas, has a positive influence and also works in his self-knowledge, self-esteem and improved social relationships with their immediate surroundings and family.

From the granular Leidenfrost state to buoyancy-driven convection.

Grains inside a vertically vibrated box undergo a transition from a density-inverted and horizontally homogeneous state, referred to as the granular Leidenfrost state, to a buoyancy-driven convective state. We perform a simulational study of the precursors of such a transition and quantify their dynamics as the bed of grains is progressively fluidized. The transition is preceded by transient convective states, which increase their correlation time as the transition point is approached. Increasingly correlated convective flows lead to density fluctuations, as quantified by the structure factor, that also shows critical behavior near the transition point. The amplitude of the modulations in the vertical velocity field are seen to be best described by a quintic supercritical amplitude equation with an additive noise term. The validity of such an amplitude equation, and previously observed collective semiperiodic oscillations of the bed of grains, suggests a new interpretation of the transition analogous to a coupled chain of vertically vibrated damped oscillators. Increasing the size of the container shows metastability of convective states, as well as an overall invariant critical behavior close to the transition.

Communication: Structure characterization of hard sphere packings in amorphous and crystalline states.

The channel size distribution in hard sphere systems, based on the local neighbor correlation of four particle positions, is investigated for all volume fractions up to jamming. For each particle, all three particle combinations of neighbors define channels, which are relevant for the concept of caging. The analysis of the channel size distribution is shown to be very useful in distinguishing between gaseous, liquid, partially and fully crystallized, and glassy (random) jammed states. A common microstructural feature of four coplanar particles is observed in crystalline and glassy jammed states, suggesting the presence of "hidden" two-dimensional order in three-dimensional random close packings.