15 resultados para Fold and flip bifurcation curves
em AMS Tesi di Dottorato - Alm@DL - Università di Bologna
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This thesis has the aim to give an overview about the tectonic history of the Epiligurian units, which crop out in the axial portion of the Northern Apennines fold-and-thrust belt, from a structural and thermal point of view, through a multiscalar and multitecnique approach. I focused on a key example of Epiligurian wedge-top basin, (Marzabotto Basin) proceeding from macro-to-microscale approach. The study started from a remote sensing analysis of the lineaments and morphostructures which affected the study area to obtain the regional faulting pattern and an overview about the main tectonic structures, used as basis for the structural investigation at the mesoscale. On the basis of this, it was possible to reconstruct the succession of tectonic events that affected the Marzabotto Basin, consisting in: i) two sets of thrusts indicating a NE-SW and NW-SE shortening of the sedimentary succession; ii) NE-SW-left lateral transtensional faults related to a strike-slip tectonic phase; iii) three main sets of extensional structures which cut and displace the previous thrusts. Normal faults are related to the post-orogenic evolution and have been dated with U-Th method, getting an age of Middle-Late Pleistocene. From a thermal point of view, apatite fission-tracks and (U-Th)/He analyses of detrital minerals and thermal modelling on the middle-upper Eocene siliciclastic deposits allowed me to better constrain the local exhumation history and correlate it with the large-scale tectonic evolution of the Northern Apennines. In particular, the Marzabotto Basin experienced a complex burial-exhumation history, consisting in two cooling cooling phases related to the growth of the Northern Apennines belt (Oligo-Miocene in age) and a later cooling which tracks the accretion in the orogenic wedge concomitant with rollback-driven extension (late Miocene-Pliocene in age). In conclusion it is possible to affirm that the study shed new light on poorly constrained elements of fold-and-thrust belt.
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Myocardial perfusion quantification by means of Contrast-Enhanced Cardiac Magnetic Resonance images relies on time consuming frame-by-frame manual tracing of regions of interest. In this Thesis, a novel automated technique for myocardial segmentation and non-rigid registration as a basis for perfusion quantification is presented. The proposed technique is based on three steps: reference frame selection, myocardial segmentation and non-rigid registration. In the first step, the reference frame in which both endo- and epicardial segmentation will be performed is chosen. Endocardial segmentation is achieved by means of a statistical region-based level-set technique followed by a curvature-based regularization motion. Epicardial segmentation is achieved by means of an edge-based level-set technique followed again by a regularization motion. To take into account the changes in position, size and shape of myocardium throughout the sequence due to out of plane respiratory motion, a non-rigid registration algorithm is required. The proposed non-rigid registration scheme consists in a novel multiscale extension of the normalized cross-correlation algorithm in combination with level-set methods. The myocardium is then divided into standard segments. Contrast enhancement curves are computed measuring the mean pixel intensity of each segment over time, and perfusion indices are extracted from each curve. The overall approach has been tested on synthetic and real datasets. For validation purposes, the sequences have been manually traced by an experienced interpreter, and contrast enhancement curves as well as perfusion indices have been computed. Comparisons between automatically extracted and manually obtained contours and enhancement curves showed high inter-technique agreement. Comparisons of perfusion indices computed using both approaches against quantitative coronary angiography and visual interpretation demonstrated that the two technique have similar diagnostic accuracy. In conclusion, the proposed technique allows fast, automated and accurate measurement of intra-myocardial contrast dynamics, and may thus address the strong clinical need for quantitative evaluation of myocardial perfusion.
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Food packaging protects food, but it can sometimes become a source of undesired contaminants. Paper based materials, despite being perceived as “natural” and safe, can contain volatile contaminants (especially if made from recycled paper) able to migrate to food, as mineral oil, phthalates and photoinitiators. Mineral oil is a petroleum product used as printing ink solvent for newspapers, magazines and packaging. From paperboard printing and from recycled fibers (if present), mineral oil migrates into food, even if dry, through the gas phase. Its toxicity is not fully evaluated, but a temporary Acceptable Daily Intake (ADI) of 0.6 mg kg-1 has been established for saturated mineral oil hydrocarbons (MOSH), while aromatic hydrocarbons (MOAH) are more toxic. Extraction and analysis of MOSH and MOAH is difficult due to the thousands of molecules present. Extraction methods for packaging and food have been optimized, then applied for a “shopping trolley survey” on over 100 Italian and Swiss market products. Instrumental analyses were performed with online LC-GC/FID. Average concentration of MOSH in paperboards was 626 mg kg-1. Many had the potential of contaminating foods exceeding temporary ADI tens of times. A long term migration study was then designed to better understand migration kinetics. Egg pasta and müesli were chosen as representative (high surface/weight ratio). They were stored at different temperatures (4, 20, 30, 40 and 60°C) and conditions (free, shelved or boxed packs) for 1 year. MOSH and MOAH kinetic curves show that migration is a fast process, mostly influenced by temperature: in egg pasta (food in direct contact with paperboard), half of MOSH is transferred to food in a week at 40°C and in 8 months at 20°C. The internal plastic bag present in müesli slowed down the startup of migration, creating a “lag time” in the curves.
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Background. Abiraterone acetate is a potent inhibitor of cytochrome P450 17 α-hydrolase (CYP17A1) that causes a reduction in the synthesis of testosterone in the adrenal glands, testes and tumor microenvironment. Blocking androgen production, abiraterone has been shown to prolong progression-free survival (PFS) and overall survival (OS) in patients with metastatic castration-resistant prostate cancer (CRPC) previously submitted to chemotherapy. The aim of our study was to verify the role of single nucleotide polymorphisms (SNPs) in predicting clinical outcome in CRPC patients treated with abiraterone after chemotherapy. Methods. We analyzed 48 CRPC consecutive patients treated with abiraterone after at least one chemotherapeutic regimen with docetaxel. DNA was extracted from peripheral blood and genotyped for four polymorphisms in the CYP17A1 gene (rs743572, rs10883783, rs17115100, rs284849). PFS and OS survival curves were used to identify statistical associations between haplotypes and clinical outcome. Results. Forty-eight Caucasian patients with metastatic CRPC treated with abiraterone were genotyped for polymorphisms in the CYP17A1 gene. All samples were evaluable for both sequencing and TaqMan Genotyping assay. The CRPC patients treated with abiraterone had a median PFS and OS of 7.6 months (95% CI: 4.3-10.5) and 17.6 months (95% CI: 10.5-19.0), respectively Statistical analyses highlighted a difference approaching statistical significance (log-rank test p = 0.0534) between rs10883783 and PFS. Other polymorphisms were not associated with a benefit from treatment with abiraterone. Conclusions. In our case series of 48 treated patients, rs10883783 only was identified as a possible predictive marker, results showing a trend toward statistical significance. Further analysis of this polymorphism is needed in larger series of patients to confirm our findings.
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In prokaryotic organisms, lower eukaryotes and plants, some important biological reactions are catalyzed by nickel-dependent enzymes, making this metal ion essential microelement for their life. On the other hand, excessive concentration of nickel into the cell, or prolonged exposure to nickel compounds, has toxic effects in living organisms. In addition, nickel has been classified by IARC as Group I human carcinogen, because of the correlation between its inhalation and increased incidence of nasal and lung cancers. The aim of this work was to investigate the nickel impact on human health, considering both its direct role on human cells and its indirect effect as essential element for human important bacteria. In humans, nickel induces N-myc downstream regulated gene 1 (NDRG1) expression, recently proposed as new target in cancer therapy. CD, light scattering and ITC were applied on the recombinant full-length protein and its C-terminal intrinsically disordered domain, for studying the NDRG1 structural and functional properties. In particular, the fold and dynamics of the C-terminal region were examined by NMR spectroscopy and site-directed spin labeling coupled to EPR, showing the features of an intrinsically disordered region. In nickel-dependent bacteria, nickel metabolism is strictly regulated, through the activity of different transcription factors. In Streptomyces griseus the expression of two superoxide dismutases (SODs) is antagonistically regulated by nickel thanks to the transcriptional complex SgSrnR/SgSrnQ. The SgSrnR protein was heterologously expressed and its activity as possible nickel sensor studied. DNaseI footprinting and β-galactosidase gene reporter assays revealed that SgSrnR functions as transcriptional activator, prompting the hypothesis of a new model to describe the activity of this complex. In addition, ITC, NMR and X-ray crystallography demonstrated that SgSrnR presents the fold typical of ArsR/SmtB transcription factors and low metal binding affinity, non compatible with a role as a nickel-sensor, function probably played by its partner SgSrnQ.
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The main goal of the Airborne project is to develop, at technology readiness level 8 (TRL8), a few selected robotic aerial technologies for quick localization of victims by avalanches by equipping drones with two forefront sensors used in SAR operations in case of avalanches, namely the ARVA and RECCO. This thesis focuses on the design, development, and guidance of the TRL8 quadrotor developed during the project. We present and describe the design method that allowed us to obtain an EMI shielded UAV capable of integrating both RECCO and ARVA sensors. Besides, is presented the avionics and power train design and building procedure in order to obtain a modular UAV frame that can be easily carried by rescuers and achieves all the performance benchmarks of the project. Additionally, in addition to the onboard algorithms, a multivariate regressive convolutional neural network whose goal is the localization of the ARVA signal is presented. On guidance, the automatic flight procedure is described, and the onboard waypoint generator algorithm is presented. The goal of this algorithm is the generation and execution of an automatic grid pattern without the need to know the map in advance and without the support of a control ground station (CGS). Moreover, we present an iterative trajectory planner that does not need pre-knowledge of the map and uses Bézier curves to address optimal, dynamically feasible, safe, and re-plannable trajectories. The goal is to develop a method that allows local and fast replannings in case of an obstacle pop up or if some waypoints change. This makes the novel planner suitable to be applied in SAR operations. The introduction of the final version of the quadrotor is supported by internal flight tests and field tests performed in real operative scenarios by the Club Alpino Italiano (CAI).
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This study aims at defining the tectonic evolution of a portion of the Caucasian region, in Georgia, which experienced a complex pattern of deformation events throughout Mesozoic and Cenozoic times. An integrated approach was applied to unravel the thermo-tectonic history of three inverted sedimentary basins from burial to exhumation. Additionally, this dissertation provides examples of structural inversion of sedimentary basins in response to far-field transmission of compressional stresses away from collision zones, contributing to elucidate the dynamics of stress partitioning during continental collisions. The Adjara-Trialeti fold-and-thrust belt in south-western Georgia results from the structural inversion of a Middle Eocene continental back-arc rift basin opened as a consequence of the Northern Neotethys slab rollback. This study quantitatively defines the subsidence and exhumation history of the Adjara-Trialeti basin, constraining its Middle Miocene inception of structural inversion. The western Kura Basin is a flexural foreland basin trapped between the Lesser Caucasus to the south and the Greater Caucasus to the north. This study constrains successive and competing episodes of flexural subsidence during Oligocene-Miocene times, followed by partial inversion through thick- and thin-skinned tectonics in response to continued convergence between the adjacent, oppositely verging orogenic belts. The Greater Caucasus results from the structural inversion of a Jurassic continental back-arc basin, but the timing of its growth is still debated. An across-strike transect in its southern central domain was studied, indicating that this sector of the Greater Caucasus experienced two phases of structural inversion during Late Cretaceous-Paleocene and Late Miocene times. Overall, the dataset presented in this dissertation points to a complex and episodic history of incremental deformation, characterised by successive phases of extensional and compressional tectonics which developed in response to sequential terrane accretion at the southwestern margin of Eurasia since Late Cretaceous times, eventually determining the current configuration of the Arabia-Eurasia collision zone.
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This PhD thesis aimed to assess the status of common sole, one of the main commercial stocks in the Adriatic Sea, using a mix of conventional and innovative techniques to provide more reliable estimates of stock status compared to past advice. First, a meta-analysis was carried out using data-poor assessment model to analyze the whole catch assemblage of rapido fishery. The outcomes were used to estimate rebuilding time and forecast catches under different harvest control rule scenarios, with a reduction of 20% of fishing effort being suggested as a way to allow most of the species to recover to sustainable levels. Secondly, an ensemble of data-rich assessment models was developed to better incorporate uncertainty by using alternative hypotheses of main parameters. This was the first time an ensemble of models has been used in the Mediterranean to provide management advice. Consistent with data-poor analysis results, the ensemble outcomes indicated that the common sole stock was showing a recovering trend probably due to the effective management actions underway in the area rather than the moderate effort reduction according to the actual management plan. Moreover, back-calculation measurements were used to fit and compare monophasic and biphasic growth curves through the use of non-linear mixed effects models. The analyses revealed that the fitting of the biphasic curve was superior, confirming the theory that growth in size would decrease as a consequence of reproductive effort. A stock assessment simulation showed how the use of the monophasic pattern would result in a critical overestimation of biomass that could lead to a greater risk of overfishing. As a final step, a simulation-testing procedure was applied to determine the best performing reference points using stock-specific characteristic. The procedure could be routinely adopted to increase transparency in reference points calculation enhancing the credibility of scientific advice.
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The aim of this research is to improve the understanding of the factors that control the formation of karst porosity in hypogene settings and its associated patterns of void-conduit networks. Subsurface voids created by hypogene dissolution may span from few microns to decametric tubes providing interconnected conduit systems and forming highly anisotropic permeability domains in many reservoirs. Characterizing the spatial-morphological organization of hypogene karst is a challenging task that has dramatic implications for the applied industry, given that only partial data can be acquired from the subsurface by indirect techniques. Therefore, two outcropping cave analogues are examined: the Cavallone-Bove Cave in the Majella Massif (Italy), and the karst systems of the Salitre Formation (Brazil). In the latter, a peculiar example of hypogene speleogenesis associated with silicification has been studied, providing an analogue of many karstified reservoirs hosted in cherts or cherty-carbonates within mixed sedimentary sequences. The first part of the thesis is focused on the relationships between fracture patterns and flow pathways in deformed units in: 1) a fold-and-thrust setting (Majella Massif); 2) a cratonic block (Brazil). These settings represent potential playgrounds for the migration and accumulation of geofluids, where hypogene conduits may affect flow pathways, fluid storage, and reservoir properties. The results indicate that localized deformation producing cross-formational fracture zones associated with anticline hinges or fault damage zones is critical for hypogene fluid migration and karstification. The second part of the thesis deals with the multidisciplinary study of hydrothermal silicification and hypogene dissolution in Calixto Cave (Brazil). Petrophysical analyses and a geochemical characterization of silica deposits are used to unravel the spatial-morphological organization of the conduit system and its speleogenesis. The novel results obtained from this cave shed new light on the relationship between hydrothermal silicification, hypogene dissolution and the development of multistorey cave systems in layered carbonate-siliciclastic sequences.
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This PhD dissertation presents a profound study of the vulnerability of buildings and non-structural elements stemming from the investigation of the Mw 5.2 Lorca 2011 earthquake; which constitutes one of the most significant earthquakes in Spain. It left nine fatalities due to falling debris from reinforced concrete buildings, 394 injured and material damage valued at 800 million euros. Within this framework, the most relevant initiatives concerning the vulnerability of buildings and the exposure of Lorca are studied. This work revealed two lines of research: the elaboration of a rational method to determine the adequacy of a specific fragility curve for the particular seismic risk study of a region; and the relevance of researching the seismic performance of non-structural elements. As a consequence, firstly, a method to assess and select fragility curves for seismic risk studies from the catalogue of those available in the literature is elaborated and calibrated by means of a case study. The said methodology is based on a multidimensional index and provides a ranking that classifies the curves in terms of adequacy. Its results for the case of Lorca led to the elaboration of new fragility curves for unreinforced masonry buildings. Moreover, a simplified method to account for the unpredictable directionality of the seism in the creation of fragility curves is contributed. Secondly, the characterisation of the seismic capacity and demand of the non-structural elements that caused most of the human losses is studied. Concerning the capacity, an analytical approach derived from theoretical considerations to characterise the complete out-of-plane seismic response curve of unreinforced masonry cantilever walls is provided; as well as a simplified and more practical trilinear version of it. Concerning the demand, several methods for characterising the Floor Response Spectra of reinforced concrete buildings are tested through case studies.
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The scope of the thesis is to broaden the knowledge about axially loaded pipe piles, that can play as foundations for offshore wind turbines based on jacket structures. The goal of the work was pursued by interpreting experimental data on large-scale model piles and by developing numerical tools for the prediction of their monotonic response to tensile and compressive loads to failure. The availability of experimental results on large scale model piles produced in two different campaigns at Fraunhofer IWES (Hannover, Germany) represented the reference for the whole work. Data from CPTs, blow counts during installation and load-displacement curves allowed to develop considerations on the experimental results and comparison with empirical methods from literature, such as CPT-based methods and Load Transfer methods. The understanding of soil-structure interaction mechanisms has been involved in the study in order to better assess the mechanical response of the sand with the scope to help in developing predictive tools of the experiments. A lack of information on the response of Rohsand 3152 when in contact with steel was highlighted, so the necessity of better assessing its response was fulfilled with a comprehensive campaign of interface shear test. It was found how the response of the sand to ultimate conditions evolve with the roughness of the steel, which is a precious information to take account of when attempting the prediction of a pile capacity. Parallel to this topic, the work has developed a numerical modelling procedure that was validated on the available large-scale model piles at IWES. The modelling strategy is intended to build a FE model whose mechanical properties of the sand come from an interpretation of commonly available geotechnical tests. The results of the FE model were compared with other predictive tools currently used in the engineering practice.
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Il presente studio rappresenta la prima applicazione della tecnica CEUS in alcune delle più diffuse specie non convenzionali, nonché la prima nei rettili. In particolare è stata investigata la perfusione di fegato e milza in 10 conigli, 10 furetti e il fegato in 8 iguane. Per quanto riguarda i mammiferi, la tecnica è risultata di facile attuazione e i risultati ottenuti erano equiparabili a quelli documentati per i piccoli animali. Maggiore variabilità si è messa in evidenza a livello splenico in entrambe le specie e nel coniglio rispetto al furetto. Nelle iguane è stata necessaria una modifica del protocollo a seguito dei tempi più lunghi delle fasi di wash in e di wash out. Le curve ottenute erano caratterizzate da picchi più bassi e TTP più lunghi, con wash out incompleto anche dopo 10 minuti di indagine. Nelle iguane l’indagine del fegato è stata approfondita grazie all’esecuzione di TC dinamiche con MDC, studio pioneristico per quanto riguarda la medicina dei rettili. L’esecuzione è avvenuta senza problemi in anestesia generale. Diffusione del MDC e conseguenti variazione di HU a livello aortico e epatico sono state considerate contemporaneamente, con costruzione di curve HU-tempo piuttosto ripetibili, entrambe caratterizzate da un wash in rapido, un picco, particolarmente alto a livello aortico, e da una fase di wash out più lento, anche qui incompleto dopo i 600 secondi di indagine. Una certa variabilità è stata notata in tre individui, risultato attendibile conseguentemente alla forte dipendenza da fattori intriseci ed estrinseci del metabolismo e della funzionalità epatica dei rettili. L’intero protocollo è stato applicato in un furetto e due iguane patologiche, al fine di evidenziare le potenzialità cliniche delle tecniche. Sebbene il numero esiguo di casi non permetta di trarre conclusioni a questo riguardo, l’ultimo capitolo della tesi vuole essere uno spunto per studi futuri.
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DNA as powerful building molecule, is widely used for the assembly of molecular structures and dynamic molecular devices with different potential applications, ranging from synthetic biology to diagnostics. The feature of sequence programmability, which makes it possible to predict how single stranded DNA molecules fold and interact with one another, allowed the development of spatiotemporally controlled nanostructures and the engineering of supramolecular devices. The first part of this thesis addresses the development of an integrated chemiluminescence (CL)-based lab-on-chip sensor for detection of Adenosine-5-triphosphate (ATP) life biomarker in extra-terrestrial environments.Subsequently, we investigated whether it is possible to study the interaction and the recognition between biomolecules and their targets, mimicking the intracellular environment in terms of crowding, confinement and compartmentalization. To this purpose, we developed a split G-quadruplex DNAzyme platform for the chemiluminescent and quantitative detection of antibodies based on antibody-induced co-localization proximity mechanism in which a split G-quadruplex DNAzyme is led to reassemble into the functional native G-quadruplex conformation as the effect of a guided spatial nanoconfinement.The following part of this thesis aims at developing chemiluminescent nanoparticles for bioimaging and photodynamic therapy applications.In chapter5 a realistic and accurate evaluation of the potentiality of electrochemistry and chemiluminescence (CL) for biosensors development (i.e., is it better to “measure an electron or a photon”?), has been achieved.In chapter 6 the emission anisotropy phenomenon for an emitting dipole bound to the interface between two media with different refractive index has been investigated for chemiluminescence detection.
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Despite the scientific achievement of the last decades in the astrophysical and cosmological fields, the majority of the Universe energy content is still unknown. A potential solution to the “missing mass problem” is the existence of dark matter in the form of WIMPs. Due to the very small cross section for WIMP-nuleon interactions, the number of expected events is very limited (about 1 ev/tonne/year), thus requiring detectors with large target mass and low background level. The aim of the XENON1T experiment, the first tonne-scale LXe based detector, is to be sensitive to WIMP-nucleon cross section as low as 10^-47 cm^2. To investigate the possibility of such a detector to reach its goal, Monte Carlo simulations are mandatory to estimate the background. To this aim, the GEANT4 toolkit has been used to implement the detector geometry and to simulate the decays from the various background sources: electromagnetic and nuclear. From the analysis of the simulations, the level of background has been found totally acceptable for the experiment purposes: about 1 background event in a 2 tonne-years exposure. Indeed, using the Maximum Gap method, the XENON1T sensitivity has been evaluated and the minimum for the WIMP-nucleon cross sections has been found at 1.87 x 10^-47 cm^2, at 90% CL, for a WIMP mass of 45 GeV/c^2. The results have been independently cross checked by using the Likelihood Ratio method that confirmed such results with an agreement within less than a factor two. Such a result is completely acceptable considering the intrinsic differences between the two statistical methods. Thus, in the PhD thesis it has been proven that the XENON1T detector will be able to reach the designed sensitivity, thus lowering the limits on the WIMP-nucleon cross section by about 2 orders of magnitude with respect to the current experiments.
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INTRODUCTION Aim of this multicentric study:to compare the short-and mid-term results of bare metal stents(BMS)and covered stents(CS)in the Kissing Stent(KS)technique. METHODS Patients undertaking a KS with BMS or CS between January 2017-August 2021 included. Morphological features of plaques were classified as per the extension of calcifications and thrombosis. Every endpoint and outcome was compared in relation to BMS or CS. All patients included received dual anti-platelets DAPT)for at least one month. RESULTS Thirty-four patients enrolled,17 treated with BMS and 17 with CS. Average age 66 years. The 80% of patients were part of TASC C-D categories. DAPT was administered to 82.4%(28/34)of patients with a mean duration of 4.4±1.6 months. Mean follow-up 32.1±17.8 months. Technical Success was 100%. Immediate Clinical Success was reached in 29 cases(85.3%). Immediate and 30-day Clinical Success was higher in CS(64.7% vs 100%, p=.01). Overall Clinical Success at 1-year follow-up was 91.2%,and resulted significantly higher in CS(82.4% vs 100%,p .04). Overall Primary Patency,Assisted Patency,and Secondary Patency at 30 days were 97.1%,97.1%,and 100%,without differences between BMS and CS(94.1% vs 100%,94.1% vs 100%,and 100% vs 100%;p =.7). Two cases(5.9%)of thrombosis were registered,and both occurred within 3 months after the procedure and both in the BMS,without statistical differences with the CS group(11.8% vs 0%,p .48). Both cases of thrombosis occurred in patients who were not treated with dual antiplatelet therapy(33.3% vs 0%,p .027). Survival statistically differed only at the mean follow-up in favour of CS(70.6% and 100%,p .04). CONCLUSIONS The endovascular approach is currently safe and effective in the treatment of AIOD,and KS offers excellent results in particular if performed with CS; however,no statistically significant differences emerged between the two types of stents in terms of patency,reintervention,and complications. DAPT seems to warrant the best results in terms of patency,although there is still no consensus about the ideal duration of administration.