Failure of hydrogenation in protecting polycyclic aromatic hydrocarbons from fragmentation

A recent study of soft X-ray absorption in native and hydrogenated coronene cations, C$_{24}$H$_{12+m}^+$ $m=0-7$, led to the conclusion that additional hydrogen atoms protect (interstellar) Polycyclic Aromatic Hydrocarbon (PAH) molecules from fragmentation [Reitsma et al., Phys. Rev. Lett. 113, 053002 (2014)]. The present experiment with collisions between fast (30-200 eV) He atoms and pyrene (C$_{16}$H$_{10+m}^+$, $m=0$, 6, and 16) and simulations without reference to the excitation method suggests the opposite. We find that the absolute carbon-backbone fragmentation cross section does not decrease but increases with the degree of hydrogenation for pyrene molecules.Comment: 10 pages, 5 figure

Body-worn triaxial accelerometer coherence and reliability related to static posturography in unilateral vestibular failure

Poichè le alterazioni della funzione vestibolare possono essere causa di disequilibrio, i principali reperti sviluppati ad oggi per misurare il controllo posturale e lintegrazione sensoriale nel danno vestibolare sono stati ottenuti grazie alla posturografia. Tuttavia, al fine di superare i problemi legati a tale genere di tecnologia, sono stati proposti gli accelerometri indossabili (ACC) come unalternativa portatile e a basso costo per la misurazione delloscillazione corporea in ambienti confortevoli. Daltro canto, nessuno studio ad oggi ha dimostrato la validità sperimentale delle misurazioni ottenute con ACC - rispetto a quelle derivanti dalla posturografia - in soggetti affetti da deficit vestibolare. Pertanto, lobiettivo del presente lavoro è stato quello di i) sviluppare e validare una strumentazione pratica che potesse consentire la misurazione dei disordini delloscillazione corporea nellambito della valutazione otoneurologica attraverso gli ACC e ii) fornire unanalisi delle oscillazioni affidabile ed automatica, che potesse implementare in modo sensibile ed accurato la possibile discriminazione di pazienti affetti da deficit vestibolare unilaterale (UVF). A tale scopo, un gruppo di 13 pazienti (sette femmine, 6 maschi; età media 48.6 ± 6.4 anni) affetti da UVF da almeno 6 mesi e un altro omogeneo di 13 soggetti sani sono stati invitati a mantenere la posizione eretta durante lesecuzione della posturografia statica (FBP) mentre indossavano a livello lombare - vicino al centro di massa - un sensore Movit® (by Captiks) costituito da accelerometri 3-D. La correlazione product-moment secondo Pearson ha dimostrato un elevato livello di corrispondenza di quattro misure, estratte da ACC e da FBP, nel dominio del tempo e di tre in quello della frequenza. Inoltre il t-test ha evidenziato che due parametri nel dominio del tempo e due in quello della frequenza si sono dimostrati affidabili nel discriminare i soggetti affetti da UVF. Tali aspetti, nel loro complesso, dovrebbero focalizzare lattenzione in ambito clinico e di ricerca su tale tecnica di registrazione, considerato larricchimento quantitativo e qualitativo di informazioni utili nella discriminazione, diagnosi e trattamento di pazienti affetti da UVF. In conclusione, noi riteniamo che la misurazione basata su ACC offra unalternativa confortevole, affidabile, economica ed efficiente utile, assieme ai test clinici di equilibrio e mobilità, in molteplici circostanze così come negli studi implicati nella diagnosi, controllo e riabilitazione di pazienti affetti da UVF

Early Noise-Induced Hearing Loss Accelerates Presbycusis Altering Aging Processes in the Cochlea

Several studies identified hearing loss as a risk factor for aging-related processes, including neurodegenerative diseases, as dementia and age-related hearing loss (ARHL). Although the association between hearing impairment in midlife and ARHL has been widely documented by epidemiological and experimental studies, the molecular mechanisms underlying this association are not fully understood. In this study, we used an established animal model of ARHL (C57BL/6 mice) to evaluate if early noise-induced hearing loss (NIHL) could affect the onset or progression of age-related cochlear dysfunction. We found that hearing loss can exacerbate ARHL, damaging sensory-neural cochlear epithelium and causing synaptopathy. Moreover, we studied common pathological markers shared between hearing loss and ARHL, demonstrating that noise exposure can worsen/accelerate redox status imbalance [increase of reactive oxygen species (ROS) production, lipid peroxidation, and dysregulation of endogenous antioxidant response] and vascular dysfunction [increased expression of hypoxia-inducible factor-1alpha (HIF-1α) and vascular endothelial growth factor C (VEGFC)] in the cochlea. Unveiling the molecular mechanisms underlying the link between hearing loss and aging processes could be valuable to identify effective therapeutic strategies to limit the effect of environmental risk factors on age-related diseases

Early cortical metabolic rearrangement related to clinical data in idiopathic sudden sensorineural hearing loss

Results in studies concerning cortical changes in idiopathic sudden sensorineural hearing loss (ISSNHL) are not homogeneous, in particular due to the different neuroimaging techniques implemented and the diverse stages of ISSNHL studied. Considering the recent advances in state-of-the-art positron emission tomography (PET) cameras, the aim of this study was to gain more insight into the neuroanatomical differences associated with the earliest stages of unilateral ISSNHL and clinical-perceptual performance changes.After an audiological examination including the mean auditory threshold (mean AT), mean speech discrimination score (mean SDS) and Tinnitus Handicap Inventory (THI), 14 right-handed ISSNHL patients underwent brain [F-18]fluorodeoxyglucose (FDG)-PET within 72 h of the onset of symptoms. When compared to an homogeneous group of 35 healthy subjects by means of statistical parametric mapping, a relative increase in FDG uptake was found in the right superior and medial frontal gyrus as well as in the right anterior cingulate cortex in ISSNHL patients. Conversely, the same group showed a significant relative decrease in FDG uptake in the right middle temporal, precentral and postcentral gyrus as well as in the left posterior cingulate cortex, left lingual, superior, middle temporal and middle frontal gyrus and in the left insula. Regression analysis showed a positive correlation between mean THI and glucose consumption in the right anterior cingulate cortex and a positive correlation between mean SDS and glucose consumption in the left precentral gyrus.The relative changes in FDG uptake found in these brain regions and the positive correlation with mean SDS and THI scores in ISSNHL could possibly highlight new aspects of cerebral rearrangement, contributing to further explain changes in those functions that support speech recognition during the sudden impairment of unilateral auditory input. (C) 2017 Elsevier B.V. All rights reserved

Vestibular rehabilitation in older adults with and without mild cognitive impairment: Effects of virtual reality using a head-mounted display

Purpose: Due to the gap in the knowledge in the field of vestibular rehabilitation the purpose of this randomized study is to highlight the outcomes of head-mounted display (HMD)implementation in older adults and patients with mild cognitive impairment (MCI), suffering from unilateral vestibular hypofunction (UVH). Materials and methods: Vestibulo-ocular reflex (VOR)gain, postural sway examination and dizziness-related and quality of life scores were collected in 12 UVH elderly and 12 UVH subjects suffering from MCI only undergoing vestibular rehabilitation and in 11 UVH elderly and 12 UVH subjects suffering from MCI undergoing a home-based HMD + vestibular rehabilitation protocol. Results: Although the within-subjects analysis found in all groups a significant (p < 0.05)improvement in posturography parameters and dizziness-related and quality of life scores and no changes in VOR gain, implementation of HMD demonstrated a significant (p < 0.05)increase in post-treatment between-group comparisons in the same tests and VOR gain with respect to those older adults and participants with MCI only undergoing vestibular rehabilitation. Positive correlations were discovered between Mini-Mental Score Exam values and pre-/post-treatment differences in (i)power spectra values in the low-frequency interval (r = 0.72)and in (ii)Dynamic Gait Index scores (r = 0.76). Conclusions: This study demonstrates that the implementation of a home-based virtual reality protocol may be a safe option in order to ameliorate VOR, postural control and the quality of life also in the vestibular impaired patients in whom the presence of cognitive decline could hinder the achievement of the goal of rehabilitation

Surgical treatment of otosclerosis leading to changes in postural control and quality of life

Objective: Evaluating postural function in patients with otosclerosis by assessing otoneurological function and balance-related quality of life before and 6 weeks after surgical treatment. Correlations between and clinical features were investigated. Methods: Thirty-three patients affected by otosclerosis underwent otoneurological examination, video Head Impulse Test (vHIT), and static posturography before and after stapedotomy. Quality of life and dizziness-related handicap were screened by means of validated questionnaires. Correlation analysis was performed in order to discover possible relations with audiological pre- and postoperative parameters. Results: A significant improvement in posturographic parameters was found. Correlation analysis yielded a negative correlation between preoperative bone conduction auditory threshold and both vHIT scores and postural performance improvement, evaluated by spectral analysis. Moreover, a positive correlation was also found between improvements in posturographic scores and quality-of-life questionnaires. Conclusion: The study results demonstrated an improvement in postural function and self-reported measures in a cohort of patients with otosclerosis 6 weeks after stapedotomy. The inverse correlation with preoperative auditory levels may reflect lesser chance for balance restoration in cases with worse sensorineural function. Possible implications for daily activities and overall quality of life were suggested by improved self-report questionnaire results. Level of Evidence: 4 Laryngoscope, 130:2448–2454, 2020