Damage identification on spatial Timoshenko arches by means of genetic algorithms

In this paper a procedure for the dynamic identification of damage in spatial Timoshenko arches is presented. The proposed approach is based on the calculation of an arbitrary number of exact eigen-properties of a damaged spatial arch by means of the Wittrick and Williams algorithm. The proposed damage model considers a reduction of the volume in a part of the arch, and is therefore suitable, differently than what is commonly proposed in the main part of the dedicated literature, not only for concentrated cracks but also for diffused damaged zones which may involve a loss of mass. Different damage scenarios can be taken into account with variable location, intensity and extension of the damage as well as number of damaged segments. An optimization procedure, aiming at identifying which damage configuration minimizes the difference between its eigen-properties and a set of measured modal quantities for the structure, is implemented making use of genetic algorithms. In this context, an initial random population of chromosomes, representing different damage distributions along the arch, is forced to evolve towards the fittest solution. Several applications with different, single or multiple, damaged zones and boundary conditions confirm the validity and the applicability of the proposed procedure even in presence of instrumental errors on the measured data.Comment: 34 pages, 19 figure

AMOA, Associazione Medici Oculisti per l'Africa, un esempio di solidariet\ue0 istituzionalizzata. La missione Zimbabwe.

AMOA (Associazione Medici Oculisti per l\u2019Africa), \ue8 un\u2019associazione di volontariato legalmente costituita, con sede a Bologna, aconfessionale che non persegue fini di lucro. L\u2019associazione, improntata al volontariato, svolge metodicamente e con continuit\ue0 attivit\ue0 di cooperazione allo sviluppo in favore delle popolazioni del Terzo Mondo ed in particolare di quelle africane. A tale scopo l\u2019associazione stabilisce con le Autorit\ue0 nazionali dei Paesi in cui opera, con le istituzioni nazionali ed internazionali operanti localmente e le organizzazioni sociali, una fattiva collaborazione nel rispetto delle sovranit\ue0 nazionali e secondo i principi della cooperazione internazionale definiti dalla Carta delle Nazioni Unite. Essa opera per mezzo di medici e paramedici volontari che offrono gratuitamente una parte del loro tempo per servire ai bisogni sanitari delle popolazioni di questi Paesi che si trovano in uno stadio di sottosviluppo sanitario in campo oculistico per mancanza di strutture, risorse economiche e umane. Tra le varie missioni effettuate possiamo menzionare quelle in Senegal, Togo, Etiopia, Madagascar, Rwanda, Cameroun, Zimbabwe. L\u2019analisi del presente lavoro verter\ue0 sull\u2019operato della\u2019associazione in Zimbabwe evidenziando: l\u2019epidemiologia delle patologie oculari della zona di intervento; il trattamento delle cause pi\uf9 frequenti di cecit\ue0: cataratta, glaucoma, malposizione palpebrale da tracoma, i traumi del bulbo oculare; lo screening delle deficienze visive nell\u2019et\ue0 scolare: ipermetropia, miopia, astigmatismo, ambliopia; la correzione della presbiopia che riduce la capacit\ue0 lavorativa dopo i 40 anni; la promozione dell\u2019educazione sanitaria nelle scuole e nei dispensari per la prevenzione primaria e secondaria delle carenze visive; l\u2019addestramento del personale scolastico locale a misurare la capacit\ue0 visiva dei bambini a partire dal periodo prescolare; l\u2019aggiornamento del personale medico alla chirurgia mediante soggiorni sia in loco che in Italia ed infine le ricadute sulle condizioni di salute e benessere dei soggetti coinvolti

Acetaldehyde, motivation and stress: Behavioral evidence of an addictive ménage à trois

Acetaldehyde (ACD) contributes to alcohol’s psychoactive effects through its own rewarding properties. Recent studies shed light on the behavioral correlates of ACD administration and the possible interactions with key neurotransmitters for motivation, reward and stress-related response, such as dopamine and endocannabinoids. This mini review article critically examines ACD psychoactive properties, focusing on behavioral investigations able to unveil ACD motivational effects and their pharmacological modulation in vivo. Similarly to alcohol, rats spontaneously drink ACD, whose presence is detected in the brain following chronic self-administration paradigm. ACD motivational properties are demonstrated by operant paradigms tailored to model several drug-related behaviors, such as induction and maintenance of operant self-administration, extinction, relapse and punishment resistance. ACD-related addictive-like behaviors are sensitive to pharmacological manipulations of dopamine and endocannabinoid signaling. Interestingly, the ACD-dopamine-endocannabinoids relationship also contributes to neuroplastic alterations of the NPYergic system, a stress-related peptide critically involved in alcohol abuse. The understanding of the ménage-a-trois among ACD, reward- and stress-related circuits holds promising potential for the development of novel pharmacological approaches aimed at reducing alcohol abuse

Role of cannabinoids in the treatment of Tinnitus

Tinnitus is a frequent symptom in audiological clinical practice characterized by an abnormal noise perceived in one or both ears or in the head, in which a patient has a conscious hearing percept in absence of external sound. Tinnitus might be caused by a homeostatic response of central dorsal cochlear nucleus auditory neurons that makes them hyperactive in compensation to auditory input loss. One hypothesis suggests that tinnitus is a sensory form of epilepsy that involves the cochlear nucleus and the inferior colliculus, which display impairment in the electrical activity in the auditory system. This alteration determines a synaptic plasticity in the dorsal cochlear nucleus that becomes a target for pharmacological compounds able to treat tinnitus. There is no effective drug treatment for tinnitus, but different studies propose the use of cannabinoid receptors agonist for their anti-epileptic activity, although their practical effects are still unclear. In this review, we want to analyze the emerging pharmacological approaches of cannabinoid receptor agonists to the therapy of tinnitus

Night-time shift work and related stress responses: A study on security guards

Work-related stress can induce a break in homeostasis by placing demands on the body that are met by the activation of two different systems, the hypothalamic\u2013pituitary\u2013adrenal axis and the sympathetic nervous system. Night-shift work alters the body\u2019s exposure to the natural light\u2013 dark schedule and disrupts circadian (daily) rhythms. The greatest effect of night-shift work is the disruption of circadian rhythms. The impact that these disruptions may have on the pathogenesis of many diseases, including cancer, is unknown. This study aims to discover the relationship among three different job activities of security guards and their stress-related responses by evaluating salivary cortisol levels and blood pressure. Methods: Ninety security guards, including night-time workers and night-time and daily-shift workers, were recruited for this study. Each security guard provided two saliva samples before and after three scheduled time points: (i) at 22:00, (ii) at 06:30, and (iii) at 14:00. Results: The results of the study showed a significant alteration in cortisol levels. Night-time shift cortisol levels significantly increased before and after the work shifts. A physiological prevalence of the vagal tone on the cardiocirculatory activity was found during night-shift work. Conclusions: This study indicates that cortisol levels and blood pressure are sensitive markers of biological responses to severe work stress. Shift-change consequences may occur at the end of the night shift when there is a significant increase in the cortisol level and a significant variation in cardiovascular parameters

Evidence that autophagy, but not the unfolded protein response, regulates the expression of IL-23 in the gut of patients with ankylosing spondylitis and subclinical gut inflammation.

OBJECTIVES: Interleukin (IL)-23 has been implicated in the pathogenesis of ankylosing spondylitis (AS). The aim of the study was to clarify the mechanisms underlying the increased IL-23 expression in the gut of AS patients. METHODS: Consecutive gut biopsies from 30 HLA-B27(+) AS patients, 15 Crohn's disease (CD) patients and 10 normal subjects were obtained. Evidence for HLA-B27 misfolding was studied. Unfolded protein response (UPR) and autophagy were assessed by RT-PCR and immunohistochemistry. The contribution of UPR and autophagy in the regulation of IL-23 expression was evaluated in in vitro experiments on isolated lamina propria mononuclear cells (LPMCs). RESULTS: Intracellular colocalisation of SYVN1 and FHCs but not a significant overexpression of UPR genes was observed in the gut of AS patients. Conversely, upregulation of the genes involved in the autophagy pathway was observed in the gut of AS and CD patients. Immunohistochemistry showed an increased expression of LC3II, ATG5 and ATG12 but not of SQSTM1 in the ileum of AS and CD patients. LC3II was expressed among infiltrating mononuclear cells and epithelial cells resembling Paneth cells (PC) and colocalised with ATG5 in AS and CD. Autophagy but not UPR was required to modulate the expression of IL-23 in isolated LPMCs of AS patients with chronic gut inflammation, CD patients and controls. CONCLUSIONS: Our data suggest that HLA-B27 misfolding occurs in the gut of AS patients and is accompanied by activation of autophagy rather than a UPR. Autophagy appears to be associated with intestinal modulation of IL-23 in AS

Airway Wall Thickness By HRCT Does Not Affect Airway Distensibility In Asthma And COPD

The mineral ushkovite has been analyzed using a combination of electron microscopy with EDX and vibrational spectroscopy. Chemical analysis shows the mineral contains P, Mg with very minor Fe. Thus, the formula of the studied ushkovite is Mg3 2+(PO4)2 8H2O. The Raman spectrum shows an intense band at 953 cm 1 assigned to the m1 symmetric stretching mode. In the infrared spectra complexity exists with multiple antisymmetric stretching vibrations observed, due to the reduced tetrahedral symmetry. This loss of degeneracy is also reflected in the bending modes. Strong infrared bands around 827 cm 1 are attributed to water librational modes. The Raman spectra of the hydroxyl-stretching region are complex with overlapping broad bands. Hydroxyl stretching vibrations are identified at 2881, 2998, 3107, 3203, 3284 and 3457 cm 1. The wavenumber band at 3457 cm 1 is attributed to the presence of FeOH groups. This complexity is reflected in the water HOH bending modes where a strong infrared band centered around 1653 cm 1 is found. Such a band reflects the strong hydrogen bonding of the water molecules to the phosphate anions in adjacent layers. Spectra show three distinct OH bending bands from strongly hydrogen-bonded, weakly hydrogen bonded water and non-hydrogen bonded water. Vibrational spectroscopy enhances our knowledge of the molecular structure of ushkovite

The transitional gap transient AT 2018hso: new insights into the luminous red nova phenomenon

Context. The absolute magnitudes of luminous red novae (LRNe) are intermediate between those of novae and supernovae (SNe), and show a relatively homogeneous spectro-photometric evolution. Although they were thought to derive from core instabilities in single stars, there is growing support for the idea that they are triggered by binary interaction that possibly ends with the merging of the two stars. Aims. AT 2018hso is a new transient showing transitional properties between those of LRNe and the class of intermediate-luminosity red transients (ILRTs) similar to SN 2008S. Through the detailed analysis of the observed parameters, our study supports that it actually belongs to the LRN class and was likely produced by the coalescence of two massive stars. Methods. We obtained ten months of optical and near-infrared photometric monitoring, and 11 epochs of low-resolution optical spectroscopy of AT 2018hso. We compared its observed properties with those of other ILRTs and LRNe. We also inspected the archival Hubble Space Telescope (HST) images obtained about 15 years ago to constrain the progenitor properties. Results. The light curves of AT 2018hso show a first sharp peak (reddening-corrected M-r = -13.93 mag), followed by a broader and shallower second peak that resembles a plateau in the optical bands. The spectra dramatically change with time. Early-time spectra show prominent Balmer emission lines and a weak [Ca II] doublet, which is usually observed in ILRTs. However, the strong decrease in the continuum temperature, the appearance of narrow metal absorption lines, the great change in the H alpha strength and profile, and the emergence of molecular bands support an LRN classification. The possible detection of a M-I similar to -8 mag source at the position of AT 2018hso in HST archive images is consistent with expectations for a pre-merger massive binary, similar to the precursor of the 2015 LRN in M101. Conclusions. We provide reasonable arguments to support an LRN classification for AT 2018hso. This study reveals growing heterogeneity in the observables of LRNe than has been thought previously, which is a challenge for distinguishing between LRNe and ILRTs. This suggests that the entire evolution of gap transients needs to be monitored to avoid misclassifications