1,013 research outputs found
Damage-imperfection indicators for the assessment of multi-leaf masonry walls under different conditions
The complexity of multi-leaf masonry walls suggests further researches on the dy- namic behaviour mainly characterized by incoherent response between the different layers. The intrinsic discontinuity and the manufacturing imperfections are amplified by the incre- mental damage that triggers different failure mechanisms that affect the dynamic parameters, such as modal shapes, frequencies and damping ratios. The dynamic identification with out- put only methodology has been proposed in this work on different multi-leaf masonry walls subjected to uniaxial compressive load. The responses of full infill, damaged infill and strengthened infill masonry panels with different widespread damage have been recorded. The evolution of the damage scenario changes the modal shapes, the related frequencies and the damping ratios that through the comparison with the data of the initial conditions can de- tect the anomalies and then the intrinsic vulnerabilities. Through the curvature modal shape methods and the structural irregularity indices applied to different phases, it was possible evaluate the imperfection and the induced damage entity
Dynamic investigation on the Mirandola bell tower in post-earthquake scenarios
After the seismic events of the 20th and 29th of May 2012 in Emilia (Italy), most of the monumental and historic buildings of the area were severely damaged. In a few structures, partial collapse mechanisms were observed (e.g. façade tilting, out-of-plane overturning of panels…). This paper presents the case-study of the bell tower of the Santa Maria Maggiore cathedral, located in Mirandola (Italy). The dynamic response of the structure was evaluated through operational modal analysis using ambient vibrations, a consolidated non-destructive procedure that estimates the dynamic parameters of the bell-tower. The dynamic tests were carried out in pre-intervention and post-intervention conditions in order to understand the sensitivity of dynamic measurements to safety interventions. Furthermore, a comparative study is made with similar cases of undamaged masonry towers up to the 6th mode. Finally, an investigation on the state of connections and of the building itself is carried out via FE model updating
Buckling of built-up columns of pultruded fiber-reinforced polymer C-sections
This paper presents the test results of an experimental investigation to evaluate the buckling behavior of built-up columns of pultruded profiles, subjected to axial compression. Specimens are assembled by using four (off the shelf) channel shaped profiles of E-glass fiber-reinforced polymer (FRP), having similar detailing to strut members in a large FRP structure that was executed in 2009 to start the restoration of the Santa Maria Paganica church in L’Aquila, Italy. This church had partially collapsed walls and no roof after the April 6, 2009, earthquake of 6.3 magnitude. A total of six columns are characterized with two different configurations for the bolted connections joining the channel sections into a built-up strut. Test results are discussed and a comparison is made with closed-form equation predictions for flexural buckling resistance, with buckling resistance values established from both eigenvalue and geometric nonlinear finite element analyses. Results show that there is a significant role played by the end loading condition, the composite action, and imperfections. Simple closed-form equations overestimate the flexural buckling strength, whereas the resistance provided by the nonlinear analysis provides a reasonably reliable numerical approach to establishing the actual buckling behavior
Spontaneous nerve root cerebrospinal fluid leaks and intracranial hypotension: case report
Spontaneous intracranial hypotension is a rare syndrome, characterized by pressure in the cerebrospinal fluid ranging between 50 and 70 mmH2O and postural headache. Its diagnosis is made through the clinical presentation, measurement of the cerebrospinal fluid pressure and neurorimage features. The clinical recognition of this pathology has been increasing and the differential diagnosis must be made with inflammatory meningeal processes and tumor. We report a case of spontaneous nerve root cerebrospinal fluid leaks in a 34 year-old man and intracranial hypotension. A literature review was performed evaluating the clinical, diagnostic and therapeutic aspects of this unusual pathology.A hipotensão intracraniana espontânea é síndrome rara, caracterizada pela diminuição da pressão no líquido cefalorraquidiano (LCR), nos valores de 50 a 70 mm H2O, e cefaléia postural. O diagnóstico é feito através do quadro clínico, da medida da pressão do LCR e do estudo radiológico do encéfalo e da coluna vertebral. O reconhecimento dessa patologia tem sido crescente em razão de suas características próprias que permitem distingui-la de processos meníngeos inflamatórios ou de tumores, evitando assim investigações desnecessárias. Relatamos um caso de hipotensão intracraniana secundária a fístula liquórica radicular espontânea em um homem de 34 anos e fizemos revisão da literatura sobre os aspectos clínicos, diagnósticos e terapêuticos dessa entidade de incidência incomum.Fundação Universidade de Caxias do Sul Disciplina de NeurologiaUniversidade Federal de São Paulo (UNIFESP) Escola Paulista de MedicinaUniversidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Departamento de Neurologia e NeurocirurgiaUniversidade de Caxias do SulUNIFESP, EPM, Depto. de Neurologia e NeurocirurgiaSciEL
Sensitivity analysis of damaged monumental structures: the example of S. Maria del Suffragio in L'Aquila
In Italy, which accounts for an impressive number of architectural heritage sites, a large part of the territory is subject to seismic risk. Nonetheless, also the two recent examples of the 2009 L'Aquila earthquake and 2012 Emilia earthquake confirmed and highlighted the vulnerability of cultural heritage structures to these types of events. In this paper the church of Santa Maria del Suffragio (Anime Sante) in L'Aquila is used as a benchmark for the experimental validation of a finite element model on the basis of the data gathered by the permanent structural health monitoring system installed on the building by IUAV in 2009. Structural health monitoring techniques have been largely applied to cultural Heritage buildings in recent times, mostly because of their non-destructive nature, and they have proven to be a valid tool in assessing the damage evolution and in characterising the global dynamic behaviour of the structure. In particular, a global sensitivity analysis technique has been applied to a finite element model. The model underwent a model updating procedure on the parameters chosen in the sensitivity analysis. The calibrated model is an invaluable tool in assessing the dynamic behaviour of the structure and may serve for several purpose
Risk factors and outcomes of oncohematologic patients admitted to Pediatric Intensive Care Unit: ONCOTIPNET, an Italian multicenter study
openNegli ultimi decenni sono stati fatti grandi progressi nell’ambito dell’oncologia pediatrica grazie a una conoscenza più profonda della biologia del cancro, che ha permesso di migliorare l’outcome dei pazienti attraverso protocolli di cura ottimizzati. Tuttavia i bambini con tumore possono sviluppare gravi complicanze legate alla malattia di base e ai trattamenti oncologici e possono necessitare di cure intensivistiche. L’obbiettivo primario del nostro studio è descrivere la popolazione di bambini affetti da tumore ricoverati nelle terapie intensive italiane considerando le variabili legate al periodo antecedente al ricovero in TIP e al ricovero in TIP stesso. L’obbiettivo secondario è identificare i fattori di rischio associati alla mortalità e alla durata di degenza.
Materiali e metodi: Questo lavoro è uno studio multicentrico a cui hanno partecipato 14 terapie intensive pediatriche italiane, costituito da una parte retrospettiva e da una parte prospettica. Nello studio sono stati inclusi 538 pazienti ricoverati in terapia intensiva pediatrica tra gennaio 2019 e aprile 2022. La fase retrospettiva ha coinvolto 239 pazienti, mentre la prospettica 299. I dati registrati riguardano sia variabili relative alla fase precedente al ricovero in terapia intensiva che al ricovero in TIP stesso. Nel nostro lavoro sono state analizzate la popolazione generale dello studio, la popolazione di pazienti con tumore solido in rapporto a quella di pazienti con tumore ematologico e la popolazione di bambini trapiantati in rapporto ai bambini non trapiantati. I fattori di rischio per mortalità e durata di degenza relativi al pre-ricovero in TIP e alla degenza in TIP sono stati analizzati mediante analisi univariate e multivariate.
Risultati: Tra i 538 pazienti inclusi nello studio il 54% erano maschi. L’età media è stata 7 anni (IRQ 2-12). Le diagnosi di malattia di base sono state le seguenti: tumore solido (51%), leucemia linfoblastica acuta (23%), leucemia mieloide acuta (6.2%), linfoma non Hodgkin (3.8%), linfoma di Hodgkin (6.1%), altro (15%). Il 19% dei pazienti erano stati sottoposti a trapianto di midollo. Le cause principali di ricovero sono state complicanze respiratorie (32%) e neurologiche (23%). La mortalità in terapia intensiva pediatrica è stata del 13%. 428 pazienti sono stati inclusi nelle analisi dei fattori di rischio per la mortalità in TIP e per la durata di degenza in TIP. Dall’analisi multivariata della mortalità sono risultate significative in pre-ricovero le seguenti variabili: HSCT (Hematopoietic Stem Cell Transplantation) (p=0.013), O-PEWS (Oncological Pediatric Early Warning Score) (p=0.010), PIM (Pediatric Index of Mortality) 3 score (p<0.001) and priorità (p=0.012); durante il ricovero le variabili: insufficienza multiorgano (p=0.004) e episodio di arresto cardiaco (p<0.001). Dall’analisi multivariata sulla durata della degenza in TIP è risultata significativa in pre-ricovero in TIP la variabile insufficienza multiorgano (p=0.049); durante la degenza le variabili: durata della ventilazione invasiva e/o non invasiva (p<0.001) e la presenza di NPT (p=0.004).
Conclusioni: Il nostro studio riporta una minor mortalità dei pazienti pediatrici oncologici ricoverati in terapia intensiva rispetto agli studi presenti in letteratura. Il riconoscimento precoce dei pazienti a più alto rischio, un’appropriata tempistica nel ricovero in TIP ed un’adeguata terapia potrebbero migliorare ancora di più la sopravvivenza dei pazienti. Il O-PEWS e lo score PIM 3 sono importanti strumenti per determinare la gravità del paziente. Hanno inoltre significato predittivo per la mortalità. Sarebbero tuttavia necessari nuovi aggiornamenti delle linee guida riguardo i criteri di ricovero in TIP, l’appropriatezza e le tempistiche del supporto intensivo in modo da poter assicurare il miglior approccio interdisciplinare e, di conseguenza, migliorare la sopravvivenzaIn the past decades, important progresses have been made in pediatric oncology thanks to a deep understanding of cancer biology that allowed improving patients’ survival and ameliorating their outcomes through the implementation of optimized treatment protocols. However, children with cancer still develop serious complications related either to their disease or to its treatment and may require intensive care. Thus, pediatric oncologic patients and particularly those who also undergo allogeneic hematopoietic stem cell transplantation during their treatment course are to be considered as a high-risk population for intensive care needs. The most common causes for pediatric intensive care unit (PICU) admission in these patients are respiratory and neurological complications, as well as sepsis and multiorgan failure. PICU treatments include respiratory support with invasive and non-invasive ventilation, renal replacement therapy, total parenteral nutrition and eventually extracorporeal membrane oxygenation. Despite various scores have been historically developed to assess the severity of patients’ clinical conditions during their hospitalization, evaluate the actual need for PICU admission and predict mortality, recent and robust studies regarding PICU admitted oncologic children are lacking in the literature.
Aim of the study: Our study is aimed at describing the pediatric oncologic population admitted to different Italian PICUs with regard to pre-PICU admission variables and during PICU stay variables. Our secondary endpoint is to identify risk factors associated with PICU mortality and length of PICU stay.
Materials and methods: This work is a multicenter retrospective and prospective study involving 14 Italian PICUs. Data were collected from a total of 538 patients admitted to 14 Italian PICUs between January 2019 and April 2022. The retrospective phase involved 239 patients, the prospective phase 299 patients. the data collected include before PICU admission variables and during PICU stay variables. These variables were analysed to describe the overall population of the study, the subpopulations of patients with solid tumor compared to children affected by an hematological neoplasm, and the subpopulations of children who underwent stem cell transplant compared to non-transplanted children. Univariate and multivariate analyses were performed to identify pre PICU admission and PICU stay risk factors for mortality outcome and for length of PICU stay outcome.
Results: The 54% of the 538 study patients were males. Median age was 7 years (IRQ 2-12). The underlying diagnoses were: solid tumor (51%), acute lymphoblastic leukemia (23%), acute myeloid leukemia (6.2%), non-Hodgkin lymphoma (3.8%), Hodgkin lymphoma (6.1%), others (15%). 19% of the patients underwent HSCT. The most common admission causes were respiratory failure (32%) and neurological deficits (23%). Mortality in PICU was 13%. 428 patients were included in the analysis of risk factors for mortality in PICU and PICU length of stay (patients admitted after surgery who stayed in PICU less than 48 hours were excluded). The multivariate analysis for risk factors associated with mortality outcome showed significant values for the following pre-PICU admission predictors: HSCT (Hematopoietic Stem Cell Transplantation) (p=0.013), O-PEWS (Oncological Pediatric Early Warning Score) (p=0.010), PIM (Pediatric Index of Mortality) 3 score (p<0.001) and priority level (severity of illness) (p=0.012); PICU stay predictors: multiorgan failure (p=0.004) and cardiac arrest (p<0.001). The multivariate analysis for risk factors associated with length of PICU stay showed significant values for multiorgan failure (p=0.049) as before PICU admission predictor; PICU stay predictors: invasive and/or non-invasive ventilation length (p<0.001) and TPN (p=0.004).
Conclusions: Our study reports a lower mortality for pediatric oncologic patients admitted to PICU compared to literature
Ceramic characterization and factography of resin-ceramic adhesive interface after different ceramic surface treatments
Orientador: Alvaro Della Bona, Altair A. Del Bel CuryTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaResumo: Este estudo avaliou o efeito do tratamento de superfície na resistência adesiva à tração (s) entre resina e as cerâmicas IPS Empress®(E1) e VITAVM7®(V7) e o modo de falha nessa interface adesiva. A metodologia proposta teve por finalidade testar a hipótese de que a s entre resina e cerâmica é controlada pelo tratamento de superfície das cerâmicas. Foram confeccionados 10 blocos de uma cerâmica a base de leucita, (E1) e de uma cerâmica feldspática com duas fases vítreas (V7), que foram polidos até a granulação de 1 µm. Os blocos de cada cerâmica foram divididos aleatoriamente em dois grupos e tiveram suas superfícies tratadas como segue (n=5): Grupos E1HF e V7HF: aplicação de ácido hidrofluorídrico a 9,5% (HF - Ultradent) aplicado por 60 s; Grupos E1CS e V7CS: jateamento com partículas de alumina modificadas por sílica (CS ¿ Cojet System, 3M-Espe), aplicado por 15 s. As superfícies cerâmicas tratadas foram lavadas, secadas e o silano foi aplicado deixando-o evaporar. Aplicaram-se duas camadas finas de adesivo (Single Bond, 3M), seguido da aplicação de camadas de 2 mm de resina composta (Z250, 3M), que foram fotopolimerizadas durante 40 s cada uma. Os blocos cerâmica-adesivo-resina composta foram seccionados em dois eixos, x e y, obtendo-se corpos-de-prova em forma de barras (n=30), com área adesiva média de 1,04 mm2. Os corpos-de-prova foram armazenados em água destilada a 37°C por uma semana antes do teste de tração em uma máquina de ensaios universal com velocidade de carga de 1.0 mm.min-1, seguido da análise microscópica da superfície fraturada. A análise estatística foi realizada pela análise de variância, teste de Tukey (a=.01) e análise de Weibull. As médias e desvio padrão da s (MPa) foram: E1HF: 29,8±4,5(a); E1CS: 24,6±5,6(b); V7HF: 22,3±4,0(b); V7CS: 15,7±6,9(c). Os valores médios de s do Grupo E1HF foram significativamente maiores que os valores médios dos demais grupos (p=0,0001). As duas cerâmicas apresentaram valores médios de s significativamente maiores quando tratadas com HF do que com CS (p=0,0001). Todas as fraturas ocorreram dentro da zona adesiva. O módulo de Weibull (m) foi mais alto para o Grupo E1HF (7,66), e o Grupo V7CS mostrou o valor mais baixo de m (2,54). Os resultados confirmam a hipótese inicial de que a s da resina à cerâmica é controlada, primariamente, pelo tratamento de superfície do material cerâmicoAbstract: This study evaluated the effect of ceramic surface treatments on tensile bond strength (s) and the mode of failure of a resin bonded to two types of ceramics, testing the hypothesis that s of ceramics to resin is controlled by the ceramic surface treatment. Methods: Ten blocks of each the hot-pressed leucite-based ceramic (E1- IPS Empress) and the two-phase glassy feldspathic ceramic (V7-VITAVM7) were fabricated, polished through 1 µm alumina abrasive, and divided into two groups per ceramic (n=5): Groups E1HF and V7HF, 9.5% hydrofluoric acid (HF) was applied for 60 s; Groups E1CS e V7CS, silica coating (CS) using Cojet System (3M-Espe) for 15 s. The treated ceramic surfaces were washed and dried. Silane was applied and let to evaporate. An adhesive resin (Single Bond, 3M) followed by a resin composite (Z250, 3M) were applied on the ceramic treated surfaces and light cured. The composite-ceramic blocks were cut to produce bar-shaped specimens with a mean bonding area of 1.04 mm2 (n=30). Specimens were stored in 37°C distilled water for 1 week before tensile loading to failure in a universal testing machine with cross-head speed of 1.0 mm.min-1. Fracture surfaces were examined under scanning electron microscope (SEM). Results were statistically analyzed using one way ANOVA, Tukey¿s test and Weibull analyses. Results: Mean s and standard deviation (MPa) values were as follows: E1HF: 29.8±4.5(a); E1CS: 24.6±5.6(b); V7HF: 22.3±4.0(b); V7CS: 15.7±6.9(c). Mean s value of Group E1HF was statistically higher than the other Groups mean values (p=0.0001). HF treatment produced significantly higher mean s value than CS treatment, independent of the ceramic material (p=0.0001). All fractures occurred within the adhesion zone. E1HF showed the highest Weibull modulus (m) value (7.66) and V7CS exhibited the lowest m value (2.54). Conclusion: Results confirmed the testing hypothesis that s of ceramics to resin is controlled primarily by the ceramic surface treatmentDoutoradoProtese DentalDoutor em Clínica Odontológic
An overview on nature-inspired optimization algorithms for Structural Health Monitoring of historical buildings
Structural Health Monitoring (SHM) of historical building is an emerging field of research aimed at the development of strategies for on-line assessment of structural condition and identification of damage in the earliest stage. Built heritage is weak against operational and environmental condition and preservation must guarantee minimum repair and non-intrusiveness. SHM provides a cost-effective management and maintenance allowing prevention and prioritization of the interventions. Recently, in computer science, mimicking nature to address complex problems is becoming more frequent. Nature-inspired approaches turn out to be extremely efficient in facing optimization, commonly used to analyze engineering processes in SHM, providing interesting advantages when compared with classic methods. This paper begins with an introduction to Natural Computing. Then, focusing on its applications to SHM, possible improvements in built heritage conservation are shown and discussed suggesting a general framework for safety assessment and damage identification of existing structures.This work was financed by FEDER funds through the Competitiveness Factors Operational Programme COMPETE and by national funds through FCT - Foundation for Science and Technology within the scope of the project POCI-01-0145-FEDER-007633info:eu-repo/semantics/publishedVersio
Recursive partitioning and Gaussian Process Regression for the detection and localization of damages in pultruded Glass Fiber Reinforced Polymer material
In this paper, a methodology for the detection and localization of damages in composite pultruded members is proposed. This is particularly relevant to thin-walled pultruded members, which are typically characterized by orthotropic behavior, anisotropic along the fibers and isotropic in the cross section. Hence, a method to detect and localize damage, and the influence these might have on the performance of thin-walled Glass Fiber Reinforced Polymer (GFRP) members, is proposed and applied to both numerical and experimental data. Specifically, the numerical and experimental modal shapes of a narrow flange pultruded profile are analyzed. The reliability of the proposed semiparametric statistical method, which is based on Gaussian Processes Regression and Bayesian-based Recursive Partitioning, is analyzed on a narrow flange profile, artificially affected by sawed notches with incremental depth. The numerical investigation is carried out via finite element models (FEMs) of the cracked beam, where the dynamic parameters and the modal shapes are computed. In total, three different crack sizes are investigated, to compare the results with the experimental ones. Finally, the proposed approach is further extended and validated on numerically simulated frame structures
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