181 research outputs found

    Calibration of the dynamic behaviour of incomplete structures in archeological sites: The case of Villa Diomede portico in Pompeii

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    This paper reports the research activities carried out on Villa Diomede in Pompeii, built during the "Pre-Roman period" (i.e. the 3rd century BC) and discovered between 1771 and 1774 during the archaeological excavations. It is one of the greatest private buildings of Pompeii and it is located on the western corner of the modern archeological site. Three levels compose the building: the ground floor, the lower quadriportico with a square plan and a series of colonnades on the four sides around the inner garden and the cryptoportico. Villa Diomede was damaged by the strong earthquake occurred in AD 63 that caused the collapse of the western pillars of the quadriportico and later damaged after the big eruption of Vesuvius in AD 79. In June 2015 a series of nondestructive tests (NDT) were carried out by the authors in order to obtain information on the state of conservation of the building and to assess its structural behavior. Direct and tomographic sonic pulse velocity tests, ground penetrating radar, endoscopies and operational modal analysis were performed on the remaining structural elements on the two levels of the Villa. The present paper reports the main outcomes and findings of ambient vibration tests implemented to extract the modal parameters in terms of eigenfrequencies, mode shapes and damping ratios. Operational modal analysis and output-only identification techniques were applied to single stone pillars of the quadriportico structure and then to the entire square colonnade of Villa Diomede. Results are then used to study the soil-structure interaction at a local level and extend the gained information for the numerical calibration of the whole structure. Thanks to this methodology a detailed model updating procedure of the quadriportico was performed to develop reliable numerical models for the implementation of advance structural and seismic analysis of this "incomplete" archaeological structure

    Operational modal analysis for the characterization of ancient water towers in Pompeii

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    In the framework of an investigation campaign carried out in June 2015 by the authors on four ancient water towers (10\u201320 BC) in the archaeological site of Pompeii, modal analysis and output-only identification techniques were employed to extract the dynamic properties in order to assess structural vulnerabilities and support numerical model updating. The four investigated towers (selected among the fourteen present within the archaeological site) are free-standing structures at least 6 m tall, belonging to the Castellum Aquae, i.e. the ancient aqueducts system of the city. During the Roman Age, until the destruction of Pompeii due to the volcanic eruption in 79 AD, water towers provided fresh water to houses, palaces and villas. This particular type of structures are classified as no. 1, 2, 3 and 4 by archaeological literature: no. 1 and 4 are made of soft stone masonry (tuff, limestone), while no. 2 and 3 are composed by brickwork masonry. The paper reports the outcomes of ambient vibration tests performed on four towers in terms of extracted modal parameters using various operational modal analysis techniques. Obtained data are then used to study numerically the soil-structure interaction problem and implement model updating procedures

    Patient’s assessment and prediction of recovery after stroke: a roadmap for clinicians

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    Background and purposeIn neurorehabilitation clinical practice, assessment is usually more oriented to evaluate patient's present status, than to plan interventions according to predicted outcomes. Therefore, we conducted an extensive review of current prognostic models available in the literature for recovery prediction of many functions and constructs, after stroke. We reported results in the form of a practical guide for clinicians, with the aim of promoting the culture of early clinical assessment for patient stratification, according to expected outcome.Recommendations for clinical practiceClinical assessment should be directed both towards the objective evaluation of the present health status, and to the prediction of expected recovery. The use of specific outcome measures with predictive value is recommended to help clinicians with the definition of sound therapeutic goals

    Use of Virtual Reality-Based Therapy in Patients with Urinary Incontinence: A Systematic Review with Meta-Analysis

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    It is estimated that over 400 million people worldwide experience some form of urinary incontinence (UI). Pelvic floor muscle training (PFMT) is commonly used in cases of urine loss. Game therapy (GT) has been suggested as a new conservative modality for UI treatments. GT represents a form of virtual reality (VR) that allows users to interact with elements of a simulated scenario. The purpose of this review was to assess the potential of using VR-based PFMT in the treatment of UI with a particular focus on the impact of this form of therapy on the patients’ muscle function, symptoms of UI and quality of life (QoL). The following electronic databases were searched: PubMed, Embase, Cochrane Library, Scopus and Web of Science. Systematic review methods were based on the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement. Electronic medical databases were searched from inception to 28 January 2021. From a total of 38 articles, 26 were analyzed after removing duplicates, then 22 records were excluded according to inclusion criteria and 4 were assessed as full texts. Finally, 2 randomized controlled trials (RCT) with 79 patients were included. For the International Consultation on Incontinence Questionnaire-Short Form (ICIQ-SF), the meta-analysis showed a significant difference in favor of the control condition (MD = 2.22; 95% CI 0.42, 4.01; I2 = 0%). Despite the popularity of the use of VR in rehabilitation, we found a scarcity of literature evaluating the application of VR in the field of UI therapy. Only one study matched all of the criteria established. The effects of VR training improved PFM function and QoL; however, these changes were comparable to those of traditional PFMT. It is not possible to reach final conclusions from one study; thus, further development of VR interventions in the field of UI treatments are needed

    An Experimental Platform for the Analysis of Polydisperse Systems Based on Light Scattering and Image Processing

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    In this work an experimental platform for light scattering analysis has been developed using image sensors, as CCD or CMOS. The main aim of this activity is the investigation of the feasibility of using these types of sensors for polydisperse systems analysis. The second purpose is the implementation of an experimental platform which is enough versatile to permit the observation of different phenomena in order to develop novel sensors/approach using data fusion

    Virtual Feedback for Arm Motor Function Rehabilitation after Stroke: A Randomized Controlled Trial

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    A single-blind randomized controlled trial was conducted to compare whether the con-tinuous visualization of a virtual teacher, during virtual reality rehabilitation, is more effective than the same treatment provided without a virtual teacher visualization, for the recovery of arm motor function after stroke. Teacher and no-teacher groups received the same amount of virtual reality therapy (i.e., 1 h/d, 5 dd/w, 4 ww) and an additional hour of conventional therapy. In the teacher group, specific feedback (“virtual-teacher”) showing the correct kinematic to be emulated by the patient was always displayed online during exercises. In the no-teacher group patients performed the same exer-cises, without the virtual-teacher assistance. The primary outcome measure was Fugl-Meyer Upper Extremity after treatment. 124 patients were enrolled and randomized, 62 per group. No differences were observed between the groups, but the same number of patients (χ2 = 0.29, p = 0.59) responded to experimental and control interventions in each group. The results confirm that the manipulation of a single instant feedback does not provide clinical advantages over multimodal feedback for arm rehabilitation after stroke, but combining 40 h conventional therapy and virtual reality provides large effect of intervention (i.e., Cohen’s d 1.14 and 0.92 for the two groups, respectively)

    Post-stroke deficit prediction from lesion and indirect structural and functional disconnection

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    Behavioural deficits in stroke reflect both structural damage at the site of injury, and widespread network dysfunction caused by structural, functional, and metabolic disconnection. Two recent methods allow for the estimation of structural and functional disconnection from clinical structural imaging. This is achieved by embedding a patient's lesion into an atlas of functional and structural connections in healthy subjects, and deriving the ensemble of structural and functional connections that pass through the lesion, thus indirectly estimating its impact on the whole brain connectome. This indirect assessment of network dysfunction is more readily available than direct measures of functional and structural connectivity obtained with functional and diffusion MRI, respectively, and it is in theory applicable to a wide variety of disorders. To validate the clinical relevance of these methods, we quantified the prediction of behavioural deficits in a prospective cohort of 132 first-time stroke patients studied at 2 weeks post-injury (mean age 52.8 years, range 22-77; 63 females; 64 right hemispheres). Specifically, we used multivariate ridge regression to relate deficits in multiple functional domains (left and right visual, left and right motor, language, spatial attention, spatial and verbal memory) with the pattern of lesion and indirect structural or functional disconnection. In a subgroup of patients, we also measured direct alterations of functional connectivity with resting-state functional MRI. Both lesion and indirect structural disconnection maps were predictive of behavioural impairment in all domains (0.16 < R2 < 0.58) except for verbal memory (0.05 < R2 < 0.06). Prediction from indirect functional disconnection was scarce or negligible (0.01 < R2 < 0.18) except for the right visual field deficits (R2 = 0.38), even though multivariate maps were anatomically plausible in all domains. Prediction from direct measures of functional MRI functional connectivity in a subset of patients was clearly superior to indirect functional disconnection. In conclusion, the indirect estimation of structural connectivity damage successfully predicted behavioural deficits post-stroke to a level comparable to lesion information. However, indirect estimation of functional disconnection did not predict behavioural deficits, nor was a substitute for direct functional connectivity measurements, especially for cognitive disorders
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