Propiedades biológicas de matrices porosas y no porosas de PCL/PFIP

Actualmente existe un alto interés en el estudio de polímeros sintéticos biodegradables para su aplicación como andamiajes biocompatibles en distintas áreas de ingeniería de tejidos. Poli(e-caprolactona) (PCL) y poli(diisopropilfumarato) (PDIPF) han demostrado ser buenos sustratos para la adhesión, el crecimiento y la diferenciación de dos líneas de células osteoblásticas, MC3T3E1 derivadas de células de calvaria ratón y UMR106 osteosarcoma de rata, sugiriendo que estos polímeros pueden ser útiles en la regeneración de tejido óseo. Para obtener un material con buenas propiedades mecánicas y una tasa de degradación intermedia entre ambos homopolímeros se ha preparado una mezcla de PCL y PDIPF compatibilizada por ultrasonido de alta intensidad. Esta mezcla ha demostrado poseer mejores propiedades mecánicas y mayor biocompatibilidad que los homopolímeros correspondientes. El objetivo de este trabajo es evaluar la actividad de células UMR106 frente a matrices porosas y no porosas de la mezcla de PCL-PFIP compatibilizadas. Las matrices porosas se obtuvieron mediante electrospraying de una solución de la mezcla en cloroformo. Las matrices no porosas se obtuvieron por casting de una solución en cloroformo. Las películas obtenidas se evaluaron por SEM y microscopia óptica, usando el software “Image J” para caracterizarlas morfológicamente. En ambas matrices se realizaron ensayos de adhesión (a 1h), proliferación (a 24 h) y actividad de Fosfatasa Alcalina (ALP) (a 24 y 48 h, control: superficie de placa de cultivo). La técnica de electrospraying permitió la obtención de matrices porosas formadas por microgotas tal como se observa mediante SEM. La adhesión y proliferación y la actividad de ALP de las células crecidas sobre las películas aumento significativamente sobre la matriz porosa respecto a la matriz no porosa. El aumento del área superficial proporcionada por la estructura porosa incrementó los marcadores de actividad celular

Coherent radiation reaction effects in laser-vacuum acceleration of electron bunches

The effects of coherently enhanced radiation reaction on the motion of subwavelength electron bunches in interaction with intense laser pulses are analyzed. The radiation reaction force behaves as a radiation pressure in the laser beam direction, combined with a viscous force in the perpendicular direction. Due to Coulomb expansion of the electron bunch, coherent radiation reaction effects only occur in the initial stage of the laser-bunch interaction while the bunch is still smaller than the wavelength. It is shown that this initial stage can have observable effects on the trajectory of the bunch. By scaling the system to larger bunch charges, these effects may be increased to such an extent that they can suppress the radial instability normally found in ponderomotive acceleration schemes, thereby enabling the full potential of laser-vacuum electron bunch acceleration to GeV energies.Comment: 31 pages, 4 figure

The home environment : influences on the health of young-old and old-old adults in Australia

The physical and societal characteristics of home have been established as important in influencing the health and wellbeing of older adults, yet these have rarely been explored together. There is also limited research into variation across age groups, with older adults often examined as a homogenous group of those 65 years and over. This study advances the knowledge base by using the concept of person–environment (P-E) fit to analyse differences in personal and home environment (physical and societal) characteristics between young-old (65–74 years) and old-old (75 and above) age groups, and to assess how these characteristics influence their self-perceived health. This cross-sectional study draws upon survey data from 1,999 older adult participants from the Australian Housing Conditions Dataset. Descriptive statistics and inferential analysis were used to assess for significant differences between age groups and a binomial logistic regression was utilised to examine influences on health. The analysis found that the factors which influence health varies appreciably between age groups. For the young-old financial strain, being on the fixed-income pension and hypertension were important contributing factors, in contrast for the old-old gender (being male), having depression and the home being modified for disability were key influences. For both age groups heart disease was a contributing factor to perceived health. The results indicate the important contribution to knowledge of incorporating a wide range of person and environment characteristics when exploring P-E fit for older adults. The inclusion of societal aspects, such as financial strain, fixed-income pension, tenure and access to community aged care services when exploring influences on health, arises as a key conclusion of the study. In terms of impact, this research is significant given rising inequalities globally and specifically in the Australian context, the need for policy measures to address income inequality, and its health and social implications for older households.https://www.cambridge.org/core/journals/ageing-and-societyFinancial Managemen

Low anti-staphylococcal IgG responses in granulomatosis with polyangiitis patients despite long-term Staphylococcus aureus exposure

Chronic nasal carriage of the bacterium Staphylococcus aureus in patients with the autoimmune disease granulomatosis with polyangiitis (GPA) is a risk factor for disease relapse. To date, it was neither known whether GPA patients show similar humoral immune responses to S. aureus as healthy carriers, nor whether specific S. aureus types are associated with GPA. Therefore, this study was aimed at assessing humoral immune responses of GPA patients against S. aureus antigens in relation to the genetic diversity of their nasal S. aureus isolates. A retrospective cohort study was conducted, including 85 GPA patients and 18 healthy controls (HC). Humoral immune responses against S. aureus were investigated by determining serum IgG levels against 59 S. aureus antigens. Unexpectedly, patient sera contained lower anti-staphylococcal IgG levels than sera from HC, regardless of the patients' treatment, while total IgG levels were similar or higher. Furthermore, 210 S. aureus isolates obtained from GPA patients were characterized by different typing approaches. This showed that the S. aureus population of GPA patients is highly diverse and mirrors the general S. aureus population. Our combined findings imply that GPA patients are less capable of mounting a potentially protective antibody response to S. aureus than healthy individuals

Evidence for a mixed mass composition at the `ankle' in the cosmic-ray spectrum

We report a first measurement for ultra-high energy cosmic rays of the correlation between the depth of shower maximum and the signal in the water Cherenkov stations of air-showers registered simultaneously by the fluorescence and the surface detectors of the Pierre Auger Observatory. Such a correlation measurement is a unique feature of a hybrid air-shower observatory with sensitivity to both the electromagnetic and muonic components. It allows an accurate determination of the spread of primary masses in the cosmic-ray flux. Up till now, constraints on the spread of primary masses have been dominated by systematic uncertainties. The present correlation measurement is not affected by systematics in the measurement of the depth of shower maximum or the signal in the water Cherenkov stations. The analysis relies on general characteristics of air showers and is thus robust also with respect to uncertainties in hadronic event generators. The observed correlation in the energy range around the `ankle' at $\lg(E/{\rm eV})=18.5-19.0$ differs significantly from expectations for pure primary cosmic-ray compositions. A light composition made up of proton and helium only is equally inconsistent with observations. The data are explained well by a mixed composition including nuclei with mass $A > 4$. Scenarios such as the proton dip model, with almost pure compositions, are thus disfavoured as the sole explanation of the ultrahigh-energy cosmic-ray flux at Earth.Comment: Published version. Added journal reference and DOI. Added Report Numbe

Relativistic Laser-Matter Interaction and Relativistic Laboratory Astrophysics

The paper is devoted to the prospects of using the laser radiation interaction with plasmas in the laboratory relativistic astrophysics context. We discuss the dimensionless parameters characterizing the processes in the laser and astrophysical plasmas and emphasize a similarity between the laser and astrophysical plasmas in the ultrarelativistic energy limit. In particular, we address basic mechanisms of the charged particle acceleration, the collisionless shock wave and magnetic reconnection and vortex dynamics properties relevant to the problem of ultrarelativistic particle acceleration.Comment: 58 pages, 19 figure

ENIGMA and global neuroscience: A decade of large-scale studies of the brain in health and disease across more than 40 countries

This review summarizes the last decade of work by the ENIGMA (Enhancing NeuroImaging Genetics through Meta Analysis) Consortium, a global alliance of over 1400 scientists across 43 countries, studying the human brain in health and disease. Building on large-scale genetic studies that discovered the first robustly replicated genetic loci associated with brain metrics, ENIGMA has diversified into over 50 working groups (WGs), pooling worldwide data and expertise to answer fundamental questions in neuroscience, psychiatry, neurology, and genetics. Most ENIGMA WGs focus on specific psychiatric and neurological conditions, other WGs study normal variation due to sex and gender differences, or development and aging; still other WGs develop methodological pipelines and tools to facilitate harmonized analyses of "big data" (i.e., genetic and epigenetic data, multimodal MRI, and electroencephalography data). These international efforts have yielded the largest neuroimaging studies to date in schizophrenia, bipolar disorder, major depressive disorder, post-traumatic stress disorder, substance use disorders, obsessive-compulsive disorder, attention-deficit/hyperactivity disorder, autism spectrum disorders, epilepsy, and 22q11.2 deletion syndrome. More recent ENIGMA WGs have formed to study anxiety disorders, suicidal thoughts and behavior, sleep and insomnia, eating disorders, irritability, brain injury, antisocial personality and conduct disorder, and dissociative identity disorder. Here, we summarize the first decade of ENIGMA's activities and ongoing projects, and describe the successes and challenges encountered along the way. We highlight the advantages of collaborative large-scale coordinated data analyses for testing reproducibility and robustness of findings, offering the opportunity to identify brain systems involved in clinical syndromes across diverse samples and associated genetic, environmental, demographic, cognitive, and psychosocial factors