Sintesi e caratterizzazione di polimeri coniugati per l'ottenimento di piste conduttive mediante tracciatura laser

Utilizzo di laser portatili per la creazione di piste conduttive su polimeri coniugati.

Distribution and state of fishery resources in the Northern and Central Adriatic Sea using trawl surveys data

The Ecosystem Approach to Fisheries represents the most recent research line in the international context, showing interest both towards the whole community and toward the identification and protection of all the “critical habitats” in which marine resources complete their life cycles. Using data coming from trawl surveys performed in the Northern and Central Adriatic from 1996 to 2010, this study provides the first attempt to appraise the status of the whole demersal community. It took into account not only fishery target species but also by-catch and discharge species by the use of a suite of biological indicators both at population and multi-specific level, allowing to have a global picture of the status of the demersal system. This study underlined the decline of extremely important species for the Adriatic fishery in recent years; adverse impact on catches is expected for these species in the coming years, since also minimum values of recruits recently were recorded. Both the excessive exploitation and environmental factors affected availability of resources. Moreover both distribution and nursery areas of the most important resources were pinpointed by means of geostatistical methods. The geospatial analysis also confirmed the presence of relevant recruitment areas in the North and Central Adriatic for several commercial species, as reported in the literature. The morphological and oceanographic features, the relevant rivers inflow together with the mosaic pattern of biocenoses with different food availability affected the location of the observed relevant nursery areas.

Operational Modal Analysis: the CEME Skywalk at UBC, Vancouver

Slender and lighter footbridges are becoming more and more popular to meet the transportation demand and the aesthetical requirements of the modern society. The widespread presence of such particular structures has become possible thanks to the availability of new, lightweight and still capable of carrying heavy loads material . Therefore, these kind of structure, are particularly sensitive to vibration serviceability problems, especially induced by human activities. As a consequence, it has been imperative to study the dynamic behaviour of such slender pedestrian bridges in order to define their modal characteristics. As an alternative to a Finite Element Analysis to find natural frequencies, damping and mode shape, a so-called Operational Modal Analysis is a valid tool to obtain these parameters through an ambient vibration test. This work provides a useful insight into the Operational Modal Analysis technique and It reports the investigation of the CEME Skywalk, a pedestrian bridge located at the University of British Columbia, in Vancouver, Canada. Furthermore, human-induced vibration tests have been performed and the dynamic characteristics derived with these tests have been compared with the ones from the ambient vibration tests. The effect of the dynamic properties of the two buildings supporting the CEME Skywalk on the dynamic behaviour of the bridge has been also investigated.

Studio reologico avanzato di bitumi modificati ed additivati:proposta di una nuova procedura di aging

Le problematiche ambientali e socio – economiche legate alla costruzione di nuove infrastrutture viarie, impongono la progettazione e costruzione di strade che combinino ad elevati standard prestazionali, la riduzione dell’impatto ambientale in fase realizzativa e manutentiva. Quanto detto avvalora il crescente utilizzo di materiali bituminosi modificati con polimeri ed additivati con cere. I primi conferiscono alla miscela maggiore elastoplasticità, incrementandone la durabilità e la resistenza a fatica. Nei secondi la presenza del materiale paraffinico contribuisce a ridurre la viscosità del bitume, il che consente il notevole abbassamento della temperatura di produzione e stesa della miscela. Numerosi studi inoltre hanno dimostrato che le caratteristiche meccaniche della pavimentazione sono fortemente influenzate dal grado di ossidazione delle componenti organiche del bitume, ovvero dal fenomeno dell’invecchiamento o aging. Risulta pertanto fondamentale affiancare allo studio reologico del bitume, prove di simulazione dell’ invecchiamento nel breve e lungo termine. Nel corso della seguente ricerca si provvederà pertanto ad analizzare leganti modificati ed additivati secondo la teoria della viscoelasticità, simulando le reali condizioni di carico ed invecchiamento alle quali il bitume è sottoposto. Tutte le prove di caratterizzazione reologica avanzata prevederanno l’utilizzo del DSR (Dynamic Shear Rheometer) in varie configurazioni di prova e si simulerà l’invecchiamento a breve termine mediante RTFOT (Rolling thin film oven test). Si proporrà inoltre una nuova procedura di aging invecchiando il bitume alla temperatura di equiviscosità o Twork , ovvero a quel valore della temperatura tale per cui, in fase di messa in opera, si avrà una distribuzione molecolare omogenea del modificante all’interno del bitume. Verranno quindi effettuate ulteriori prove reologiche sui leganti invecchiati a tale temperatura. Si darà infine supporto ai risultati della ricerca effettuando prove chimiche con la tecnica analitica FTIR (Fourier Transform Infrared Spectroscopy), analizzando i cambiamenti molecolari avvenuti nel bitume a seguito dell’aggiunta del modificante e dell’invecchiamento.

Libertà di manifestazione del pensiero e tecniche argomentative delle Corti costituzionali

La ricerca consta di quattro capitoli: nella prima parte si analizzano, in prospettiva empirica, i canoni argomentativi utilizzati dalla Corte costituzionale italiana. Tali canoni possono essere generalmente distinti in due grandi famiglie: giuridico-interpretativi per un verso, e ed empirico fattuali per un altro. In un secondo capitolo si è visto come la Corte costituzionale italiana ha frutto uso di questi canoni nella sua giurisprudenza italiana in tema di diritto soggettivo di libertà di espressione e di mezzi di comunicazione del pensiero. Nel primo caso la Corte costituzionale ha fatto ricorso a canoni interpretativi testuali, mentre nel secondo ad argomentazioni empiriche spesso accompagnate da un giudizio di proporzionalità sull'intervento legislativo. Nella terza parte del lavoro si è invece descritta la giurisprudenza della Corte Suprema americana: è stata analizzata l'evoluzione delle tecniche argomentativi in tema di libertà di espressione: partendo dall'ad hoc balancing e dal definitional balancing si è giunti alla descrizione dei diversi livelli di scrutinio e alla progressiva concettualizzazione delle categorie espressive. Infine nel quarto capitolo si sono messe a confronto le due giurisprudenze: si è potuto così notare che la progressiva categorizzazione del diritto di libertà negli Stati Uniti ha dato esiti maggiormente garantisti, mentre più liberisti in relazione alle concrete dinamiche di formazione del discorso pubblico. Viceversa, in Italia i canoni testuali hanno originato una giurisprudenza più restrittiva quanto al diritto soggettivo e più egualitaria quanto al sistema della libertà di espressione. In ogni caso, entrambe le esperienze evidenziano il ruolo di policy-maker delle Corti costituzionali nei moderni ordinamenti liberal-democratici.

ROS generate dalle NAD(P)H ossidasi nella segnalazione redox in linee cellulari leucemiche

Discovery of the Nox family has led to the concept that ROS are “intentionally” generated and are biologically functional in various cell types. Over the last decades, ROS have been shown to be involved in several physiological and pathological processes and ROS producing enzymes have been suggested as a target for drug development. The mechanism involved in the prosurvival effect of cytokines on the human acute myeloid leukaemia cell lines M07e and B1647 is investigated. A decrease in intracellular reactive oxygen species (ROS) content, glucose transport activity and cell survival was observed in the presence of inhibitors of plasma membrane ROS sources, such as DPI and apocynin, and by small interference RNA for NOX2 in M07e cells. Furthermore, Nox generated ROS are required to sustain B1647 cell viability and proliferation; in fact, antioxidants such as EUK-134 or Nox inhibitors and siRNA direct cells to apoptotic cell death, suggesting that manipulation of cellular NOX2 and NOX4 could affect survival of leukemic cells. Moreover, hydrogen peroxide has been long thought to be freely diffusible but recent evidence suggest that specific mammalian aquaporin homologues (AQP8) possess the capacity to channel H2O2 across membrane. In this thesis is shown that inhibition of aquaporins diminishes intracellular ROS accumulation either when H2O2 is produced by Nox enzymes or when is added exogenously to the medium. These data suggest that specific inhibition of Nox enzymes and AQP8 could be an interesting novel anti-leukemic strategy.

Theoretical studies of microfluidics: "walking" drops and "melting" snowflakes.

The present PhD thesis summarizes two examples of research in microfluidics. Both times water was the subject of interest, once in the liquid state (droplets adsorbed on chemically functionalized surfaces), the other time in the solid state (ice snowflakes and their fractal behaviour). The first problem deals with a slipping nano-droplet of water adsorbed on a surface with photo-switchable wettability characteristics. Main focus was on identifying the underlying driving forces and mechanical principles at the molecular level of detail. Molecular Dynamics simulation was employed as investigative tool owing to its record of successfully describing the microscopic behaviour of liquids at interfaces. To reproduce the specialized surface on which a water droplet can effectively “walk”, a new implicit surface potential was developed. Applying this new method the experimentally observed droplet slippage could be reproduced successfully. Next the movement of the droplet was analyzed at various conditions emphasizing on the behaviour of the water molecules in contact with the surface. The main objective was to identify driving forces and molecular mechanisms underlying the slippage process. The second part of this thesis is concerned with theoretical studies of snowflake melting. In the present work snowflakes are represented by filled von Koch-like fractals of mesoscopic beads. A new algorithm has been developed from scratch to simulate the thermal collapse of fractal structures based on Monte Carlo and Random Walk Simulations (MCRWS). The developed method was applied and compared to Molecular Dynamics simulations regarding the melting of ice snowflake crystals and new parameters were derived from this comparison. Bigger snow-fractals were then studied looking at the time evolution at different temperatures again making use of the developed MCRWS method. This was accompanied by an in-depth analysis of fractal properties (border length and gyration radius) in order to shed light on the dynamics of the melting process.

Progetto e modellazione CAD di micro turbine eoliche

Progetto di due turbine eoliche di piccola potenza per alimentare utenze remote. Sia la turbina ad asse verticale che quella ad asse orizzontale sono state dimensionate andando ad ottimizzare il funzionamento per un vento di 7.5 m/s ed un carico dato da un alternatore da 500W. Entrambe le turbine sono poi state modellate al CAD e sono stati realizzati i disegni costruttivi di alcuni elementi delle stesse.

International cooperation in endourology: percutaneous and flexible ureteroscopic treatment of lower pole kidney stones

Introduction Lower pole kidney stones represent at time a challenge for the urologist. The gold standard treatment for intrarenal stones <2 cm is Extracorporeal Shock Wave Lithotripsy (ESWL) while for those >2 cm is Percutaneous Nephrolithotomy (PCNL). The success rate of ESWL, however, decreases when it is employed for lower pole stones, and this is particularly true in the presence of narrow calices or acute infundibular angles. Studies have proved that ureteroscopy (URS) is an efficacious alternative to ESWL for lower pole stones <2 cm, but this is not reflected by either the European or the American guidelines. The aim of this study is to present the results of a large series of flexible ureteroscopies and PCNLs for lower pole kidney stones from high-volume centers, in order to provide more evidences on the potential indications of the flexible ureteroscopy for the treatment of kidney stones. Materials and Methods A database was created and the participating centres retrospectively entered their data relating to the percutaneous and flexible ureteroscopic management of lower pole kidney stones. Patients included were treated between January 2005 and January 2010. Variables analyzed included case load number, preoperative and postoperative imaging, stone burden, anaesthesia (general vs. spinal), type of lithotripter, access location and size, access dilation type, ureteral access sheath use, visual clarity, operative time, stone-free rate, complication rate, hospital stay, analgesic requirement and follow-up time. Stone-free rate was defined as absence of residual fragments or presence of a single fragment <2 mm in size at follow-up imaging. Primary end-point was to test the efficacy and safety of flexible URS for the treatment of lower pole stones; the same descriptive analysis was conducted for the PCNL approach, as considered the gold standard for the treatment of lower pole kidney stones. In this setting, no statistical analysis was conducted owing to the different selection criteria of the patients. Secondary end-point consisted in matching the results of stone-free rates, operative time and complications rate of flexible URS and PCNL in the subgroup of patients harbouring lower pole kidney stones between 1 and 2 cm in the higher diameter. Results A total 246 patients met the criteria for inclusion. There were 117 PCNLs (group 1) and 129 flexible URS (group 2). Ninety-six percent of cases were diagnosed by CT KUB scan. Mean stone burden was 175±160 and 50±62 mm2 for groups 1 and 2, respectively. General anaesthesia was induced in 100 % and 80% of groups 1 and 2, respectively. Pneumo-ultrasonic energy was used in 84% of cases in the PCNL group, and holmium laser in 95% of the cases in the flexible URS group. The mean operative time was 76.9±44 and 63±37 minutes for groups 1 and 2 respectively. There were 12 major complications (11%) in group 1 (mainly Grade II complications according to Clavidien classification) and no major complications in group 2. Mean hospital stay was 5.7 and 2.6 days for groups 1 and 2, respectively. Ninety-five percent of group 1 and 52% of group 2 required analgesia for a period longer than 24 hours. Intraoperative stone-free rate after a single treatment was 88.9% for group 1 and 79.1% for group 2. Overall, 6% of group 1 and 14.7% of group 2 required a second look procedure. At 3 months, stone-free rates were 90.6% and 92.2% for groups 1 and 2, respectively, as documented by follow-up CT KUB (22%) or combination of intra-venous pyelogram, regular KUB and/or kidney ultrasound (78%). In the subanalysis conducted comparing 82 vs 65 patients who underwent PCNL and flexible URS for lower pole stones between 1 and 2 cm, intreoperative stone-free rates were 88% vs 68% (p= 0.03), respectively; anyway, after an auxiliary procedure which was necessary in 6% of the cases in group 1 and 23% in group 2 (p=0.03), stone-free rates at 3 months were not statistically significant (91.5% vs 89.2%; p=0.6). Conversely, the patients undergoing PCNL maintained a higher risk of complications during the procedure, with 9 cases observed in this group versus 0 in the group of patients treated with URS (p=0.01) Conclusions These data highlight the value of flexible URS as a very effective and safe option for the treatment of kidney stones; thanks to the latest generation of flexible devices, this new technical approach seems to be a valid alternative in particular for the treatment of lower pole kidney stones less than 2 cm. In high-volume centres and in the hands of skilled surgeons, this technique can approach the stone-free rates achievable through PCNL in lower pole stones between 1 and 2 cm, with a very low risk of complications. Furthermore, the results confirm the high success rate and relatively low morbidity of modern PCNL for lower pole stones, with no difference detectable between the prone and supine position.

Role of nitric oxide and endocannabinoids in synaptic plasticity in the perirhinal cortex and in visual recognition memory

Introduction and aims of the research Nitric oxide (NO) and endocannabinoids (eCBs) are major retrograde messengers, involved in synaptic plasticity (long-term potentiation, LTP, and long-term depression, LTD) in many brain areas (including hippocampus and neocortex), as well as in learning and memory processes. NO is synthesized by NO synthase (NOS) in response to increased cytosolic Ca2+ and mainly exerts its functions through soluble guanylate cyclase (sGC) and cGMP production. The main target of cGMP is the cGMP-dependent protein kinase (PKG). Activity-dependent release of eCBs in the CNS leads to the activation of the Gαi/o-coupled cannabinoid receptor 1 (CB1) at both glutamatergic and inhibitory synapses. The perirhinal cortex (Prh) is a multimodal associative cortex of the temporal lobe, critically involved in visual recognition memory. LTD is proposed to be the cellular correlate underlying this form of memory. Cholinergic neurotransmission has been shown to play a critical role in both visual recognition memory and LTD in Prh. Moreover, visual recognition memory is one of the main cognitive functions impaired in the early stages of Alzheimer’s disease. The main aim of my research was to investigate the role of NO and ECBs in synaptic plasticity in rat Prh and in visual recognition memory. Part of this research was dedicated to the study of synaptic transmission and plasticity in a murine model (Tg2576) of Alzheimer’s disease. Methods Field potential recordings. Extracellular field potential recordings were carried out in horizontal Prh slices from Sprague-Dawley or Dark Agouti juvenile (p21-35) rats. LTD was induced with a single train of 3000 pulses delivered at 5 Hz (10 min), or via bath application of carbachol (Cch; 50 μM) for 10 min. LTP was induced by theta-burst stimulation (TBS). In addition, input/output curves and 5Hz-LTD were carried out in Prh slices from 3 month-old Tg2576 mice and littermate controls. Behavioural experiments. The spontaneous novel object exploration task was performed in intra-Prh bilaterally cannulated adult Dark Agouti rats. Drugs or vehicle (saline) were directly infused into the Prh 15 min before training to verify the role of nNOS and CB1 in visual recognition memory acquisition. Object recognition memory was tested at 20 min and 24h after the end of the training phase. Results Electrophysiological experiments in Prh slices from juvenile rats showed that 5Hz-LTD is due to the activation of the NOS/sGC/PKG pathway, whereas Cch-LTD relies on NOS/sGC but not PKG activation. By contrast, NO does not appear to be involved in LTP in this preparation. Furthermore, I found that eCBs are involved in LTP induction, but not in basal synaptic transmission, 5Hz-LTD and Cch-LTD. Behavioural experiments demonstrated that the blockade of nNOS impairs rat visual recognition memory tested at 24 hours, but not at 20 min; however, the blockade of CB1 did not affect visual recognition memory acquisition tested at both time points specified. In three month-old Tg2576 mice, deficits in basal synaptic transmission and 5Hz-LTD were observed compared to littermate controls. Conclusions The results obtained in Prh slices from juvenile rats indicate that NO and CB1 play a role in the induction of LTD and LTP, respectively. These results are confirmed by the observation that nNOS, but not CB1, is involved in visual recognition memory acquisition. The preliminary results obtained in the murine model of Alzheimer’s disease indicate that deficits in synaptic transmission and plasticity occur very early in Prh; further investigations are required to characterize the molecular mechanisms underlying these deficits.

Il Libro del naufragio. Edizione e commento

Edizione e commento della raccolta di miracoli mariani denominata "Libro del Naufragio" secondo la lezione del ms Firenez, Laurenziana, Ashburham 546