34 research outputs found

    Extreme Ultra-Violet Spectroscopy of the Lower Solar Atmosphere During Solar Flares

    Full text link
    The extreme ultraviolet portion of the solar spectrum contains a wealth of diagnostic tools for probing the lower solar atmosphere in response to an injection of energy, particularly during the impulsive phase of solar flares. These include temperature and density sensitive line ratios, Doppler shifted emission lines and nonthermal broadening, abundance measurements, differential emission measure profiles, and continuum temperatures and energetics, among others. In this paper I shall review some of the advances made in recent years using these techniques, focusing primarily on studies that have utilized data from Hinode/EIS and SDO/EVE, while also providing some historical background and a summary of future spectroscopic instrumentation.Comment: 34 pages, 8 figures. Submitted to Solar Physics as part of the Topical Issue on Solar and Stellar Flare

    Origins of the Ambient Solar Wind: Implications for Space Weather

    Full text link
    The Sun's outer atmosphere is heated to temperatures of millions of degrees, and solar plasma flows out into interplanetary space at supersonic speeds. This paper reviews our current understanding of these interrelated problems: coronal heating and the acceleration of the ambient solar wind. We also discuss where the community stands in its ability to forecast how variations in the solar wind (i.e., fast and slow wind streams) impact the Earth. Although the last few decades have seen significant progress in observations and modeling, we still do not have a complete understanding of the relevant physical processes, nor do we have a quantitatively precise census of which coronal structures contribute to specific types of solar wind. Fast streams are known to be connected to the central regions of large coronal holes. Slow streams, however, appear to come from a wide range of sources, including streamers, pseudostreamers, coronal loops, active regions, and coronal hole boundaries. Complicating our understanding even more is the fact that processes such as turbulence, stream-stream interactions, and Coulomb collisions can make it difficult to unambiguously map a parcel measured at 1 AU back down to its coronal source. We also review recent progress -- in theoretical modeling, observational data analysis, and forecasting techniques that sit at the interface between data and theory -- that gives us hope that the above problems are indeed solvable.Comment: Accepted for publication in Space Science Reviews. Special issue connected with a 2016 ISSI workshop on "The Scientific Foundations of Space Weather." 44 pages, 9 figure

    Virtual Ontogeny of Cortical Growth Preceding Mental Illness

    Get PDF
    Background: Morphology of the human cerebral cortex differs across psychiatric disorders, with neurobiology and developmental origins mostly undetermined. Deviations in the tangential growth of the cerebral cortex during pre/perinatal periods may be reflected in individual variations in cortical surface area later in life. Methods: Interregional profiles of group differences in surface area between cases and controls were generated using T1-weighted magnetic resonance imaging from 27,359 individuals including those with attention-deficit/hyperactivity disorder, autism spectrum disorder, bipolar disorder, major depressive disorder, schizophrenia, and high general psychopathology (through the Child Behavior Checklist). Similarity of interregional profiles of group differences in surface area and prenatal cell-specific gene expression was assessed. Results: Across the 11 cortical regions, group differences in cortical area for attention-deficit/hyperactivity disorder, schizophrenia, and Child Behavior Checklist were dominant in multimodal association cortices. The same interregional profiles were also associated with interregional profiles of (prenatal) gene expression specific to proliferative cells, namely radial glia and intermediate progenitor cells (greater expression, larger difference), as well as differentiated cells, namely excitatory neurons and endothelial and mural cells (greater expression, smaller difference). Finally, these cell types were implicated in known pre/perinatal risk factors for psychosis. Genes coexpressed with radial glia were enriched with genes implicated in congenital abnormalities, birth weight, hypoxia, and starvation. Genes coexpressed with endothelial and mural genes were enriched with genes associated with maternal hypertension and preterm birth. Conclusions: Our findings support a neurodevelopmental model of vulnerability to mental illness whereby prenatal risk factors acting through cell-specific processes lead to deviations from typical brain development during pregnancy

    The Link Between Autonomic Nervous System and Rheumatoid Arthritis : From Bench to Bedside

    Get PDF
    Neuronal stimulation is an emerging field of research focused on the management and treatment of various diseases through the reestablishment of physiological homeostasis. Electrical vagus nerve stimulation has recently been proposed as a revolutionary therapeutic option for rheumatoid arthritis (RA) in combination with or even as a replacement for conventional and biological drugs. In the past few years, disruption of the autonomic system has been linked to RA onset and activity. Novel research on the link between the autonomic nervous system and the immune system (immune-autonomics) has paved the way for the development of innovative RA management strategies. Clinical evidence supports this approach. Cardiovascular involvement, in terms of reduced baroreflex sensitivity and heart rate variability-derived indices, and mood disorders, common comorbidities in patients with RA, have been linked to autonomic nervous system dysfunction, which in turn is influenced by increased levels of circulating pro-inflammatory cytokines. This narrative review provides an overview of the autonomic nervous system and RA connection, discussing most of the common cardiac and mental health-related RA comorbidities and their potential relationships to systemic and joint inflammation

    Advances in poly(4-aminodiphenylaniline) nanofibers preparation by electrospinning technique

    No full text
    Polyaniline (PANI) nanofibers are drawing a great deal of interest from academia and industry due to their multiple applications, especially in biomedical field. PANI nanofibers were successfully electrospun for the first time by MacDiarmid and co-workers at the beginning of the millennium and since then many efforts have been addressed to improve their quality. However, traditional PANI prepared from aniline monomer shows some drawbacks, such as presence of toxic (i.e., benzidine) and inorganic (salts and metals) co-products, that complicate polymer post-treatment, and low solubilityin common organic solvents, making hard its processing by electrospinning technique. Some industrial sectors, such as medical and biomedical, need to employ materials free from toxic and polluting species. In this regard, the oxidative polymerization of N-(4-aminophenyl)aniline, aniline dimer, to produce poly(4-aminodiphenylaniline), P4ADA, a kind of PANI, represents an innovative alternative to the traditional synthesis because the obtained polymer results free from carcinogenic and/or polluting co-products, and, moreover, more soluble than traditional PANI. This latter feature can be exploited to obtain P4ADA nanofibers by electrospinning technique. In this paper we report the advances obtained in the P4ADA nanofibers electrospinnig. A comparison among polyethylene oxide (PEO), polymethyl methacrylate (PMMA) and polystyrene (PS), as the second polymer to facilitate the electrospinning process, is shown. In order to increase the conductivity of P4ADA nanofibers, two strategies were adopted and compared: selective insulating binder removal from electrospun nanofibers by a rinsing tratment, afterwards optimizing the minimum amount of binder necessary for the electrospinning process. Moreover, the effect of PEO/P4ADA weight ratio on the fibers morphology and conductivity was highlighted

    A multivariate neuromonitoring approach to neuroplasticity-based computerized cognitive training in recent onset psychosis

    Get PDF
    Two decades of studies suggest that computerized cognitive training (CCT) has an effect on cognitive improvement and the restoration of brain activity. Nevertheless, individual response to CCT remains heterogenous, and the predictive potential of neuroimaging in gauging response to CCT remains unknown. We employed multivariate pattern analysis (MVPA) on whole-brain resting-state functional connectivity (rsFC) to (neuro)monitor clinical outcome defined as psychosis-likeness change after 10-hours of CCT in recent onset psychosis (ROP) patients. Additionally, we investigated if sensory processing (SP) change during CCT is associated with individual psychosis-likeness change and cognitive gains after CCT. 26 ROP patients were divided into maintainers and improvers based on their SP change during CCT. A support vector machine (SVM) classifier separating 56 healthy controls (HC) from 35 ROP patients using rsFC (balanced accuracy of 65.5%, P\u2009<\u20090.01) was built in an independent sample to create a naturalistic model representing the HC-ROP hyperplane. This model was out-of-sample cross-validated in the ROP patients from the CCT trial to assess associations between rsFC pattern change, cognitive gains and SP during CCT. Patients with intact SP threshold at baseline showed improved attention despite psychosis status on the SVM hyperplane at follow-up (p\u2009<\u20090.05). Contrarily, the attentional gains occurred in the ROP patients who showed impaired SP at baseline only if rsfMRI diagnosis status shifted to the healthy-like side of the SVM continuum. Our results reveal the utility of MVPA for elucidating treatment response neuromarkers based on rsFC-SP change and pave the road to more personalized interventions

    Breaking the vicious circle: Onabotulinum toxin A in children with therapy-refractory dysfunctional voiding

    No full text
    Introduction An increased activity of the external urethral sphincter or pelvic floor muscles during voluntary voiding leads to dysfunctional voiding. Frequently reported symptoms are urinary incontinence, urinary tract infections and high post-void residuals. Dysfunctional voiding is a common problem in school-aged children and despite various treatment options, 10-40% of the children remain therapy-refractory. Objective The aim of this study is to evaluate the effectiveness of Onabotulinum toxin-A (BTX-A) injections in the external urethral sphincter in children with therapy-refractory dysfunctional voiding. Patients and methods Patients with therapy-refractory dysfunctional voiding who have received BTX-A injections in the external urethral sphincter from 2010 to 2013 were analysed. Children with known neuropsychiatric disorders were excluded. All children had abnormal flow patterns and increased pelvic floor tone during uroflowmetry/EMG studies. They had received at least five sessions of urotherapy and two sessions of pelvic floor physical therapy prior to treatment. A total of 100 IU of BTX-A was injected in the external urethral sphincter at the 3, 9 and 12 o\'clock positions. Our main outcome measures were urinary incontinence, recurrent urinary tract infections and post-void residual. Results A total of twenty patients, of whom 16 girls, with a median age of 9 years (range 5-14) were treated with BTX-A. The median follow-up was 13 months (range 5-34). Post-void residual decreased by 75% after BTX-A, from a median of 47.5 ml (16.3-88.5 ml) to 0 ml (0.0-28.0 ml) (p = 0.001) Six patients had a post-void residual < 20 ml prior to treatment. After BTX-A sixteen patients had a post-void residual <20 ml (Figure). No significant changes in uroflowmetry results was seen. Sixteen children are no longer daily incontinent, of whom 9 became completely dry (p = 0.0001). Eleven patients suffered from recurrent urinary tract infections prior to treatment. After BTX-A five children remained infection free, while the other six experienced only one urinary tract infection during follow-up (p = 0.003). Fourteen patients received additional urotherapy after BTX-A. Repeat injections were necessary in four patients after initial satisfactory results, with repeated good clinical responses. Two children showed no improvement after first BTX-A injection. No serious adverse events were reported. Discussion The results in this homogenous group of patients confirm the conclusions of previous studies in opting BTX-A in the external urethral sphincter to be a viable treatment option for the therapy-refractory group of patients with dysfunctional voiding. What is new, is that in most of our patients post-injection urotherapy was used to amplify the BTX-A effect. During our long-term follow-up the satisfactory results were sustained, similar to the results of the long-term follow-up presented by Vricella et al. [1]. The retrospective character and relative small sample size are limitations of this study. Conclusions This study shows safe and persistent satisfactory results during our average 13-month follow-up in 90% of our patients with therapy-refractory dysfunctional voiding. A prospective study using validated and standardized measurements will be performed to affirm our results and evaluate the exact role of post-injection urotherapy
    corecore