Calculated energy loss of swift light ions in platinum and gold: importance of the target electronic excitation spectrum

Understanding and predicting the energy loss of swift ions in metals is important for many applications of charged particle beams, such as analysis and modification of materials, and recently for modelling metal nanoparticle radiosensitisation in ion beam cancer therapy. We have calculated the stopping power of the transition metals Pt and Au for protons and alpha particles in a wide energy range, using the dielectric formalism, which realistically accounts for the excitation spectrum of each metal through the Mermin Energy Loss Function - Generalised Oscillator Strength methodology. For each combination of projectile, energy and target, we have considered: (i) the equilibrium charge state of the projectile through the target, (ii) the energy-loss due to electron capture and loss processes, and (iii) the energy loss resulting from the polarisation of the projectile's electronic cloud due to the self-induced electric field. Our calculated stopping powers show a fairly good agreement with the available experimental data for platinum and gold, particularly the most recent ones around the stopping power maximum, which validates the methodology we have used to be further extended to other transition metals. For the materials studied (platinum and gold), two commonly used and different sources of the experimental excitation spectrum yield comparable calculated stopping powers and mean excitation energies, the latter being closer to the most recent data provided in a recent ICRU Report than to previous compilations. Despite the small differences in the sources of excitation spectra of these metals, they lead to practically the same stopping power results as far as they reproduce the main excitation features of the material and fulfil physically motivated sum rules.Comment: 7 pages, 2 figure

Encapsulation and sedimentation of nanomaterials through complex coacervation

Altres ajuts: the ICN2 is funded by the CERCA programme/Generalitat de Catalunya.Hypothesis: Nanoparticles removal from seawage water is a health and environmental challenge, due to the increasing use of these materials of excellent colloidal stability. Herein we hypothesize to reach this objective through complex coacervation, a straightforward, low-cost process, normally accomplished with non-toxic and biodegradable macromolecules. Highly dense polymer-rich colloidal droplets (the coacervates) obtained from a reversible charge-driven phase separation, entrap suspended nanomaterials, allowing their settling and potential recovery. Experiments: In this work we apply this process to highly stable aqueous colloidal dispersions of different surface charge, size, type and state (solid or liquid). We systematically investigate the effects of the biopolymers excess and the nanomaterials concentration and charge on the encapsulation and sedimentation efficiency and rate. This strategy is also applied to real laboratory water-based wastes. Findings: Long-lasting colloidal suspensions are succesfully destabilized through coacervate formation, which ensures high nanomaterials encapsulation efficiencies (~85%), payloads and highly tranparent supernatants (%T ~90%), within two hours. Lower polymer excess induces faster clearance and less sediments, while preserving effective nanomaterials removal. Preliminary experiments also validate the method for the clearance of real water residuals, making complex coacervation a promising scalable, low-cost and ecofriendly alternative to concentrate, separate or recover suspended micro/nanomaterials from aqueous sludges

Colloidal systems in bone regeneration. Is the size important

Poly lactic-co-glycolic acid (PLGA) is one of the most widely used synthetic polymers for development of delivery systems for drugs and therapeutic biomolecules. Its properties and versatility make it a reference polymer in the manufacturing of nano and microparticles to encapsulate and deliver a wide variety of hydrophobic and hydrophilic molecules, including biomolecules such as proteins or nucleic acids that must be released in a controlled way [1]. Delivery of growth factors such as bone morphogenetic proteins, and specially BMP-2, is an attractive therapeutic strategy for bone tissue engineering. However, their administration is problematic due to their short biological half-lives, localized action and rapid clearance. Consequently, its clinical use requires high doses far exceeding its physiological concentration which implies possible side effects and high costs. These barriers might be overcome by developing new delivery systems which allow a better control of the release rate in order to achieve the desired concentrations in specific site and time [2]. With this aim, in this preliminary study we have synthesized PLGA particles with different diameters, from nano (200 nm) to micro scale (12.5 μm) via double emulsion procedure, in order to study the influence of size in the release profile of lysozyme, which has been selected as an appropriate model for BMP2. A physico-chemical characterization of the particles was done, followed by a complete study on the encapsulation efficiency, cumulative protein release and bioactivity of the released enzyme with and without co-encapsulated bovine serum albumin, a protective biomolecule that can prevent protein instability during emulsification process. Additionally, fluorescently labeled lysozyme was used to study the protein distribution and the influence of particle size on the in vitro cellular uptake.Universidad de Málaga. Campus Internacional de Andalucía Tec

Excitation and ionisation cross-sections in condensed-phase biomaterials by electrons down to very low energy: application to liquid water and genetic building blocks

Electronic excitations and ionisations produced by electron impact are key processes in the radiation-induced damage mechanisms in materials of biological relevance, underlying important medical and technological applications, including radiotherapy, radiation protection in manned space missions and nanodevice fabrication techniques. However, experimentally measuring all the necessary electronic interaction cross-sections for every relevant material is an arduous task, so it is necessary having predictive models, sufficiently accurate yet easily implementable. In this work we present a model, based on the dielectric formalism, to provide reliable ionisation and excitation cross-sections for electron-impact on complex biomolecular media, taking into account their condensed-phase nature. We account for the indistinguishability and exchange between the primary beam and excited electrons, for the molecular electronic structure effects in the electron binding, as well as for higher-order corrections to the first Born approximation. The resulting approach yields total ionisation cross-sections, energy distributions of secondary electrons, and total electronic excitation cross-sections for condensed-phase biomaterials, once the electronic excitation spectrum is known, either from experiments or from a predictive model. The results of this methodology are compared with the available experimental data in water and DNA/RNA molecular building blocks, showing a very good agreement and a great predictive power in a wide range of electron incident energies, from the large values characteristic of electron beams down to excitation threshold. The proposed model constitutes a very useful procedure for computing the electronic interaction cross-sections for arbitrary biological materials in a wide range of electron incident energies.Comment: 18 pages, 10 figure

Use of a truncated conical tank to improve underwater acoustic experiments

Peer Reviewe

Expression of Musashi-1 During Osteogenic Differentiation of Oral MSC: An In Vitro Study

Supplementary materials can be found at https://www.mdpi.com/1422-0067/20/9/2171/s1Background: Musashi-1 (MSI1) is a negative regulator of mesenchymal stromal cell (MSC) differentiation which in turn favors cell proliferation. However, little is known about its expression by MSC from the oral cavity and in the context of osteogenic differentiation. Aim: The aim of this study was to analyze the expression of MSI1 in the context of osteogenic differentiation of MSC derived from the oral cavity. Material/methods: For this in vitro study, MSC were isolated from six different origins of the oral cavity. They were extensively characterized in terms of proliferative and clonogenicity potential, expression of stemness genes (MYC, NANOG, POU5F1, and SOX2), expression of surface markers (CD73, CD90, CD105, CD14, CD31, CD34, and CD45) and adipo-, chondro- and osteogenic differentiation potential. Then, osteogenic differentiation was induced and the expression of MSI1 mRNA and other relevant markers of osteogenic differentiation, including RUNX2 and Periostin, were also evaluated. Results: Cell populations from the alveolar bone (pristine or previously grafted with xenograft), dental follicle, dental germ, dental pulp, and periodontal ligament were obtained. The analysis of proliferative and clonogenicity potential, expression of the stemness genes, expression of surface markers, and differentiation potential showed similar characteristics to those of previously published MSC from the umbilical cord. Under osteogenic differentiation conditions, all MSC populations formed calcium deposits and expressed higher SPARC. Over time, the expression of MSI1 followed different patterns for the different MSC populations. It was not significantly different than the expression of RUNX2. In contrast, the expression of MSI1 and POSTN and RUNX2 were statistically different in most MSC populations. Conclusion: In the current study, a similar expression pattern of MSI1 and RUNX2 during in vitro osteogenic differentiation was identified.The authors of this investigation were partially supported by Research Groups #CTS-138 (F.O.) and #CTS-1028 (M.P.-M., P.G.-M.) (Junta de Andalucía, Spain), a grant from MIS Implant Technologies Ltd. (M.P.-M., D.A.-G., P.G.-M.), the Youth Employment Initiative (YEI) from the European Commission (R.S.-U.), and the Instituto de Salud Carlos III, Spain (www.isciii.es) and Fondo Europeo de Desarrollo Regional (FEDER, from the European Union), through the research grants PI15/00794 and CPII15/00032 (P.A)

Clinical, epidemiological and therapeutic characterization of children with congenital heart disease

Introducción: la cardiología pediátrica ha evolucionado considerablemente en los últimos años sobre la base de nuevos conocimientos embriológicos, patológicos y fisiológicos. Este progreso no ha sido ajeno al desarrollo de nuevas tecnologías. Estimándose actualmente entre 650,000 y 1,300 000 adultos con malformaciones cardiacas. Objetivo: caracterizar de forma clínica, epidemiológica y terapéutica de los pacientes con cardiopatías congénitas ingresados en el Hospital Infantil Norte en el período comprendido de enero 2017 a diciembre del año 2019. Variables clínicas, epidemiológicas y terapéuticas.Métodos: se realizó un estudio descriptivo y transversal con el objetivo de caracterizar los pacientes ingresados en el Hospital Infantil Norte Docente “Juan de la Cruz Martínez Maceira” con el diagnóstico de Cardiopatías Congénitas.Resultados: se evidenció que el 71 % correspondió al sexo masculino, en pacientes de un año a cinco años fueron los de mayor número con (58 %) en este grupo predomino el sexo masculino con 39 %, el síntoma que tuvo mayor presencia fue el soplo cardiaco con 53 %, este a su vez en el sexo masculino con un 20 %. En lo referente al diagnóstico se observó dominio de los pacientes con comunicación interauricular, con un 37 % de estos un 20 % fueron del sexo masculino. Conclusiones: los pacientes con cardiopatías congénitas constituyen un grupo con especificidades tales como; la edad, el momento del diagnóstico y la terapéutica empleada, la cual los ubica como una entidad de observación relativamente frecuente en la población pediátrica.Introduction: pediatric cardiology has evolved considerably in recent years on the basis of new embryological, pathological and physiological knowledge. This progress has not been unrelated to the development of new technologies. It is currently estimated that between 650,000 and 1,300,000 adults have cardiac malformations. Objective: to characterize clinically, epidemiologically and therapeutically the patients with congenital heart disease admitted to the Hospital Infantil Norte from January 2017 to December 2019. Clinical, epidemiological and therapeutic variables.Methods: a descriptive and cross-sectional study was carried out with the aim of characterizing patients admitted to the Hospital Infantil Norte Docente "Juan de la Cruz Martínez Maceira" with the diagnosis of Congenital Heart Disease.ResResults: it was evidenced that 71 % corresponded to the male sex, in patients from one year to five years old were the ones with the highest number (58 %) in this group the male sex predominated with 39 %, the symptom that had the highest presence was the cardiac murmur with 53 %, this in turn in the male sex with 20 %. Regarding the diagnosis, 37% of the patients with atrial septal defect were male, 20 % of whom were male.Conclusions: patients with congenital heart disease constitute a group with specificities such as age, time of diagnosis and therapy used, which places them as an entity of relatively frequent observation in the pediatric population

The role of heart rate on the associations between body composition and heart rate variability in children with overweight/obesity : the ActiveBrains project

Background: Heart rate variability (HRV) is negatively associated with body mass index and adiposity in several populations. However, less information is available about this association in children with overweight and obesity, especially severe/morbid obesity, taking into consideration the dependence of HRV on heart rate (HR). Objectives: (1) to examine associations between body composition measures and HRV, (2) to study differences in HRV between children with overweight and severe/morbid obesity; and (3) to test whether relationships and differences tested in objectives 1 and 2, respectively are explained by the dependency of HRV on HR. Methods: A total of 107 children with overweight/obesity (58% boys, 10.03 +/- 1.13 years) participated in this study. Body composition measures were evaluated by Dual-energy X-ray absorptiometry (DXA). HRV parameters were measured with Polar RS800CXR (R). Results: Body composition measures were negatively associated with HRV indicators of parasympathetic activity (beta values ranging from -0.207 to -0.307, all p 0.05). Conclusion: All associations between adiposity/obesity and HRV could be explained by HR, suggesting a key confounding role of HR in HRV studies in children with weight disturbances