A new approach for the dynamic modelling of the human knee

Mathematical models of the knee joint are important tools which have both theoretical and practical applications. They are used by researchers to fully understand the stabilizing role of the components of the joint, by engineers as an aid for prosthetic design, by surgeons during the planning of an operation or during the operation itself, and by orthopedists for diagnosis and rehabilitation purposes. The principal aims of knee models are to reproduce the restraining function of each structure of the joint and to replicate the relative motion of the bones which constitute the joint itself. It is clear that the first point is functional to the second one. However, the standard procedures for the dynamic modelling of the knee tend to be more focused on the second aspect: the motion of the joint is correctly replicated, but the stabilizing role of the articular components is somehow lost. A first contribution of this dissertation is the definition of a novel approach — called sequential approach — for the dynamic modelling of the knee. The procedure makes it possible to develop more and more sophisticated models of the joint by a succession of steps, starting from a first simple model of its passive motion. The fundamental characteristic of the proposed procedure is that the results obtained at each step do not worsen those already obtained at previous steps, thus preserving the restraining function of the knee structures. The models which stem from the first two steps of the sequential approach are then presented. The result of the first step is a model of the passive motion of the knee, comprehensive of the patello-femoral joint. Kinematical and anatomical considerations lead to define a one degree of freedom rigid link mechanism, whose members represent determinate components of the joint. The result of the second step is a stiffness model of the knee. This model is obtained from the first one, by following the rules of the proposed procedure. Both models have been identified from experimental data by means of an optimization procedure. The simulated motions of the models then have been compared to the experimental ones. Both models accurately reproduce the motion of the joint under the corresponding loading conditions. Moreover, the sequential approach makes sure the results obtained at the first step are not worsened at the second step: the stiffness model can also reproduce the passive motion of the knee with the same accuracy than the previous simpler model. The procedure proved to be successful and thus promising for the definition of more complex models which could also involve the effect of muscular forces.

The social construction of cooperation: exchange, identification and collective intentions within the organization

My aim is to develop a theory of cooperation within the organization and empirically test it. Drawing upon social exchange theory, social identity theory, the idea of collective intentions, and social constructivism, the main assumption of my work implies that both cooperation and the organization itself are continually shaped and restructured by actions, judgments, and symbolic interpretations of the parties involved. Therefore, I propose that the decision to cooperate, expressed say as an intention to cooperate, reflects and depends on a three step social process shaped by the interpretations of the actors involved. The first step entails an instrumental evaluation of cooperation in terms of social exchange. In the second step, this “social calculus” is translated into cognitive, emotional and evaluative reactions directed toward the organization. Finally, once the identification process is completed and membership awareness is established, I propose that individuals will start to think largely in terms of “We” instead of “I”. Self-goals are redefined at the collective level, and the outcomes for self, others, and the organization become practically interchangeable. I decided to apply my theory to an important cooperative problem in management research: knowledge exchange within organizations. Hence, I conducted a quantitative survey among the members of the virtual community, “www.borse.it” (n=108). Within this community, members freely decide to exchange their knowledge about the stock market among themselves. Because of the confirmatory requirements and the structural complexity of the theory proposed (i.e., the proposal that instrumental evaluations will induce social identity and this in turn will causes collective intentions), I use Structural Equation Modeling to test all hypotheses in this dissertation. The empirical survey-based study found support for the theory of cooperation proposed in this dissertation. The findings suggest that an appropriate conceptualization of the decision to exchange knowledge is one where collective intentions depend proximally on social identity (i.e., cognitive identification, affective commitment, and evaluative engagement) with the organization, and this identity depends on instrumental evaluations of cooperators (i.e., perceived value of the knowledge received, assessment of past reciprocity, expected reciprocity, and expected social outcomes of the exchange). Furthermore, I find that social identity fully mediates the effects of instrumental motives on collective intentions.

Study of the circulation processes in the northern Adriatic sea - coastal area and Venice lagoon inlets

This work is a detailed study of hydrodynamic processes in a defined area, the littoral in front of the Venice Lagoon and its inlets, which are complex morphological areas of interconnection. A finite element hydrodynamic model of the Venice Lagoon and the Adriatic Sea has been developed in order to study the coastal current patterns and the exchanges at the inlets of the Venice Lagoon. This is the first work in this area that tries to model the interaction dynamics, running together a model for the lagoon and the Adriatic Sea. First the barotropic processes near the inlets of the Venice Lagoon have been studied. Data from more than ten tide gauges displaced in the Adriatic Sea have been used in the calibration of the simulated water levels. To validate the model results, empirical flux data measured by ADCP probes installed inside the inlets of Lido and Malamocco have been used and the exchanges through the three inlets of the Venice Lagoon have been analyzed. The comparison between modelled and measured fluxes at the inlets outlined the efficiency of the model to reproduce both tide and wind induced water exchanges between the sea and the lagoon. As a second step, also small scale processes around the inlets that connect the Venice lagoon with the Northern Adriatic Sea have been investigated by means of 3D simulations. Maps of vorticity have been produced, considering the influence of tidal flows and wind stress in the area. A sensitivity analysis has been carried out to define the importance of the advection and of the baroclinic pressure gradients in the development of vortical processes seen along the littoral close to the inlets. Finally a comparison with real data measurements, surface velocity data from HF Radar near the Venice inlets, has been performed, which allows for a better understanding of the processes and their seasonal dynamics. The results outline the predominance of wind and tidal forcing in the coastal area. Wind forcing acts mainly on the mean coastal current inducing its detachment offshore during Sirocco events and an increase of littoral currents during Bora events. The Bora action is more homogeneous on the whole coastal area whereas the Sirocco strengthens its impact in the South, near Chioggia inlet. Tidal forcing at the inlets is mainly barotropic. The sensitivity analysis shows how advection is the main physical process responsible for the persistent vortical structures present along the littoral between the Venice Lagoon inlets. The comparison with measurements from HF Radar not only permitted a validation the model results, but also a description of different patterns in specific periods of the year. The success of the 2D and the 3D simulations on the reproduction both of the SSE, inside and outside the Venice Lagoon, of the tidal flow, through the lagoon inlets, and of the small scale phenomena, occurring along the littoral, indicates that the finite element approach is the most suitable tool for the investigation of coastal processes. For the first time, as shown by the flux modeling, the physical processes that drive the interaction between the two basins were reproduced.

New catalytic processes for the synthesis of adipic acid

The aim of my Ph.D. research was to study the new synthetic ways for the production of adipic acid. Three different pathways were studied: i) oxidation of cyclohexanone with molecular oxygen using Keggin – heteropolycompounds as the catalyst, ii) Baeyer – Villiger oxidation of cyclohexanone with hydrogen peroxide in the presence of two different heterogeneous catalysts, titanium silicalite and silica grafted decatungstate, iii) two step synthesis of adipic acid starting from cyclohexene via 1,2-cyclohexanediol. The first step was catalyzed by H2WO4 in the presence of the phase transfer catalyst, the oxidant was hydrogen peroxide. The second step, oxidation of 1,2 – cyclohexanediol was performed in the presence of oxygen and the heterogeneous catalyst – ruthenium on alumina. The results of my research showed that: i) Oxidation of cyclohexanone with molecular oxygen using Keggin heteropolycompounds is possible, anyway the conversion of ketone is low and the selectivity to adipic acid is lowered by the consecutive reaction to from lower diacids. Moreover it was found out, that there are two mechanisms involved: redox type and radicalic chain-reaction autoxidation. The presence of the different mechanism is influenced by the reaction condition. ii) It is possible to perform thermally activated oxidation of cyclohexanone and obtain non negligible amount of the products (caprolactone and adipic acid). Performing the catalyzed reaction it was demonstrated that the choice of the reaction condition and of the catalyst plays a crucial role in the product selectivity, explaining the discrepancies between the literature and our research. iii) Interesting results can be obtained performing the two step oxidation of cyclohexene via 1,2-cyclohexanediol. In the presence of phase transfer catalyst it is possible to obtain high selectivity to alcohol with stoichiometric amount of oxidant. In the second step of the synthesis, the conversion of alcohol is rather low with modest selectivity to adipic acid

Influence of genetic variants and post transcriptional factors on imatinib transporters as determinants of the pharmacological response

Introduction – Although imatinib (IM) is a recognized gold standard in chronic myeloid leukemia (CML) therapy, resistance has emerged in a significant proportion of patients. Aim – The aim of this study was: (1) to investigate the role of genetic variants in genes encoding for IM transporters, as candidate of IM responsiveness and (2) to test the influence of miRNAs on IM response, focusing on efflux transporters. Methods – As a first step, a panel of polymorphisms (SNPs) was genotyped in a subgroup population of 189 patients enrolled in the Tyrosine Kinase Inhibitor Optimization and Selectivity (TOPS) trial. The association with cytogenetic response and molecular response (MR) was assessed for each SNP. As a second step, an in vitro IM-resistant model (K-562 CML cell line) was established. miRNAs profiles were analyzed using Taqman arrays and in silico search was performed for miRNAs deregulated after IM treatment. mRNA and protein expression were quantified using TaqMan realtime PCR and Western blotting, respectively. Results – (1) Among Caucasian patients, ABCB1 rs60023214 significantly correlated with complete MR (P = 0.005). Concerning SNPs combination in IM uptake transporters, the associations with treatment outcomes were statistically significant for both major and complete MR (P = 0.005 and P = 0.01, respectively). (2) ABCB1 protein was not expressed under any conditions of treatment, differently from ABCG2. Two deregulated miRNAs, namely miR-212 and miR-328, were identified to be inversely correlated with ABCG2 (r2= 0.57; p=0.03 and r2=0.47; p=0.06, respectively). Experiments of loss and gain of function confirmed the functional influence of these miRNAs on ABCG2. Conclusion – The multiple candidate gene approach identified single and combination of SNPs that can be proposed as predictor of IM response. The in vitro study suggested that IM resistance could be mediated by miRNA-dependent mechanism. Further studies are needed to validate these preliminary findings.

Memoria e short story postcoloniale femminile: Anita Desai e Alice Munro

In ogni capitolo, l’atto del ricordare viene indagato nelle diverse valenze che lo mettono in rapporto diretto con la nostalgia e l’oblio. L’analisi dei testi letterari copre un arco di tempo di quasi un secolo, partendo dalle innovazioni tecnico-stilistiche realizzate da Katherine Mansfield fino all’eccezionale ricchezza e al meritato successo di pubblico e critica della scrittrice canadese Alice Munro. La bibliografia dei testi primari e secondari è strutturata con criteri tematici e cronologici.

Capitale sociale e sistema del valore: Il caso del pesce azzurro in Puglia

The aim of my project is to find operational strategies for increasing the commercial exploitation of fish in Apulia region and to acquire a thorough knowledge of several important aspects of this system order to propose concrete, suitable and appropriate development tools. The plan is to analyze the impact that the socio-economic context has on blue fish systems of fishing and marketing in the various maritime regions. The sector of fishery is typified by a settled downward trend due to both communitarian policies driving towards a reduction of the fishery effort and to reduction of fishing resources. In the same time in Italy a increasing of costs (expecially fuel) and a reduction of market prices, because of the increasing of imports, are observed. Although a big part of Italian fishing fleet is to be referred to Apulia region, this dynamics are worsen, here, also because of market inefficiency and lack of integration and cooperation among fishermen. In this first part of my work I have investigated two areas that are relevant for regional fishery. On a first step I have evaluated fish amount for each kind of dealer working in each one of the two areas than, according to Porter's value chain analysis theory. Than i have applied the approach of value system to evaluate the value chains of the firm's supplier, the firm of fishery itself, and the firms distribution channels. Distribution of value has been resulted different but very unfavorable to fisherman in both investigated areas. The second step of my study has been the evaluation of the social capital value in both areas, defining the networks of fishery consistence and number of their mutual relationship. Results lay stress on a relation to an higher social capital value and a distribution of value system more profitable for fishermen.

Physiological and structural aspects of fruit and vegetable mild processing

Over the past years fruit and vegetable industry has become interested in the application of both osmotic dehydration and vacuum impregnation as mild technologies because of their low temperature and energy requirements. Osmotic dehydration is a partial dewatering process by immersion of cellular tissue in hypertonic solution. The diffusion of water from the vegetable tissue to the solution is usually accompanied by the simultaneous solutes counter-diffusion into the tissue. Vacuum impregnation is a unit operation in which porous products are immersed in a solution and subjected to a two-steps pressure change. The first step (vacuum increase) consists of the reduction of the pressure in a solid-liquid system and the gas in the product pores is expanded, partially flowing out. When the atmospheric pressure is restored (second step), the residual gas in the pores compresses and the external liquid flows into the pores. This unit operation allows introducing specific solutes in the tissue, e.g. antioxidants, pH regulators, preservatives, cryoprotectancts. Fruit and vegetable interact dynamically with the environment and the present study attempts to enhance our understanding on the structural, physico-chemical and metabolic changes of plant tissues upon the application of technological processes (osmotic dehydration and vacuum impregnation), by following a multianalytical approach. Macro (low-frequency nuclear magnetic resonance), micro (light microscopy) and ultrastructural (transmission electron microscopy) measurements combined with textural and differential scanning calorimetry analysis allowed evaluating the effects of individual osmotic dehydration or vacuum impregnation processes on (i) the interaction between air and liquid in real plant tissues, (ii) the plant tissue water state and (iii) the cell compartments. Isothermal calorimetry, respiration and photosynthesis determinations led to investigate the metabolic changes upon the application of osmotic dehydration or vacuum impregnation. The proposed multianalytical approach should enable both better designs of processing technologies and estimations of their effects on tissue.

Possibilities for the healthy and nutritional improvement of confectionery and sweet products.

The overall objective of this PhD was to investigate the possibility to increase the nutritional value of confectionary products by the use of natural ingredients with healthy functions. The first part of the thesis focused on the possible substitution of the most characteristic component of confectionary products, i.e. refined sugar. Many natural whole sweetening alternatives are available, though not widely used; the use of molasses, the byproduct of sugar beet and cane production, still rich in healthy components as minerals and phytochemicals is hereby discussed; after having verified molasses effectiveness in oxidative stress counteraction on liver cultured cells, the higher antioxidant capacity of a sweet food prepared with molasses instead of refined sugar was confirmed. A second step of the project dealt with another main ingredient of various sweet products, namely wheat. Particularly, the exploitation of soft and durum wheat byproducts could be another sustainable strategy to improve the healthy value of confectionery. The isolation of oligosaccharides with bioactive functions form different fractions of the wheat milling stream was studied and the new ingredients were shown to have a high dietary fiber and antioxidants content. As valid alternative, product developers should consider the appealing and healthy addition of ancient grains flour to sweet baked goods. The possibility of substituting the modern whole durum wheat with the ancient Kamut® khorasan was considered, and the antioxidant and anti-inflammatory effects of these grains were evaluated and compared both in vitro and in vivo on rats. Finally, since high consumption of confectionery is a risk factor for obesity, a possible strategy for the counteraction of this disease was investigated. The ability of three bioactives in inhibiting adipocytes differentiation was investigated. In fact, theoretically, compounds able to influence adipogenesis could be used in the formulation of functional sweet products and contribute to prevent obesity.

A chemical-loop approach for the generation of hydrogen by means of ethanol reforming

The work investigates the feasibility of a new process aimed at the production of hydrogen with inherent separation of carbon oxides. The process consists in a cycle in which, in the first step, a mixed metal oxide is reduced by ethanol (obtained from biomasses). The reduced metal is then contacted with steam in order to split the water and sequestrating the oxygen into the looping material’s structure. The oxides used to run this thermochemical cycle, also called “steam-iron process” are mixed ferrites in the spinel structure MeFe2O4 (Me = Fe, Co, Ni or Cu). To understand the reactions involved in the anaerobic reforming of ethanol, diffuse reflectance spectroscopy (DRIFTS) was used, coupled with the mass analysis of the effluent, to study the surface composition of the ferrites during the adsorption of ethanol and its transformations during the temperature program. This study was paired with the tests on a laboratory scale plant and the characterization through various techniques such as XRD, Mössbauer spectroscopy, elemental analysis... on the materials as synthesized and at different reduction degrees In the first step it was found that besides the generation of the expected CO, CO2 and H2O, the products of ethanol anaerobic oxidation, also a large amount of H2 and coke were produced. The latter is highly undesired, since it affects the second step, during which water is fed over the pre-reduced spinel at high temperature. The behavior of the different spinels was affected by the nature of the divalent metal cation; magnetite was the oxide showing the slower rate of reduction by ethanol, but on the other hand it was that one which could perform the entire cycle of the process more efficiently. Still the problem of coke formation remains the greater challenge to solve.

Innovative techniques for sport turf managing: Agronomic and phyisiological implications

The growing substrate of the putting greens is considered a key factor for a healthy turf ecosystem. Actually detailed study on the effects of growth promoting bacteria and biostimulants on a professional sport turf are very limited. This thesis aimed to study the effectiveness of different microorganisms and biostimulants in order to improve the knowledge relative to the relationship between the beneficial microflora and root apparatus of sport turfs. The research project was divided in three principal steps: Initially, commercial products based on biostimulants and microorganisms were tested on a Lolium perenne L. essence grown in a controlled-environment. The principal evaluations were the study of the habitus of plants, biomass production and length of leaves and roots. Were studied the capacity of colonization of microorganisms within root tissues and rhizosphere. In the second step were developed two different biostimulant solutions based on effective microorganisms, mycorrhizae and humic acids. This test was conducted both on an Agrostis stolonifera putting green (Modena Golf & Country Club) in a semi-field condition and within a growth chamber on a Lolium perenne L. essence. Fungicide and chemicals applications were suspended in order to assess the effectiveness of the inoculants for nutrition and control of pests. In the last step, different microorganism mixes and biostimulants were tested on an experimental putting green in the Turf Research Center (TRC) (Virginia Tech, United States) in a real managing situation. The effects of different treatments were studied maintaining all chemicals and mechanicals managements scheduled during a sport season. Both growth-chamber and field results confirmed the capacity of microorganisms based biostimulants to promote the physiologic conditions of the plants, improve the growth of the roots and enhance the aesthetic performance of the turf. Molecular analysis confirmed the capacity of microorganisms to colonize the root tissues.

Optimization of purification procedures in organic semiconductor synthesis for improving the performances of organic field-effect transistors

The aim of the research activity focused on the investigation of the correlation between the degree of purity in terms of chemical dopants in organic small molecule semiconductors and their electrical and optoelectronic performances once introduced as active material in devices. The first step of the work was addressed to the study of the electrical performances variation of two commercial organic semiconductors after being processed by means of thermal sublimation process. In particular, the p-type 2,2′′′-Dihexyl-2,2′:5′,2′′:5′′,2′′′-quaterthiophene (DH4T) semiconductor and the n-type 2,2′′′- Perfluoro-Dihexyl-2,2′:5′,2′′:5′′,2′′′-quaterthiophene (DFH4T) semiconductor underwent several sublimation cycles, with consequent improvement of the electrical performances in terms of charge mobility and threshold voltage, highlighting the benefits brought by this treatment to the electric properties of the discussed semiconductors in OFET devices by the removal of residual impurities. The second step consisted in the provision of a metal-free synthesis of DH4T, which was successfully prepared without organometallic reagents or catalysts in collaboration with Dr. Manuela Melucci from ISOF-CNR Institute in Bologna. Indeed the experimental work demonstrated that those compounds are responsible for the electrical degradation by intentionally doping the semiconductor obtained by metal-free method by Tetrakis(triphenylphosphine)palladium(0) (Pd(PPh3)4) and Tributyltin chloride (Bu3SnCl), as well as with an organic impurity, like 5-hexyl-2,2':5',2''-terthiophene (HexT3) at, in different concentrations (1, 5 and 10% w/w). After completing the entire evaluation process loop, from fabricating OFET devices by vacuum sublimation with implemented intentionally-doped batches to the final electrical characterization in inherent-atmosphere conditions, commercial DH4T, metal-free DH4T and the intentionally-doped DH4T were systematically compared. Indeed, the fabrication of OFET based on doped DH4T clearly pointed out that the vacuum sublimation is still an inherent and efficient purification method for crude semiconductors, but also a reliable way to fabricate high performing devices.

Verso il consumo sostenibile: i prodotti biologici nelle abitudini alimentari degli italiani

Scegliere di consumare in modo sostenibile significa passare ad un nuovo modello di consumo. Tale modello richiede una maggiore consapevolezza e responsabilità da parte dei consumatori, unite all'adozione di nuovi stili di vita e di scelte d’acquisto, che permettano il raggiungimento di elevati livelli di benessere nel rispetto dell'ambiente. Un notevole sforzo è stato compiuto recentemente dai policy maker per incoraggiare il consumo sostenibile quali implementazioni dello sviluppo sostenibile. Ancora lunga, tuttavia, è la strada da percorrere per raggiungere pienamente questo obiettivo. Tra i prodotti sostenibili, il biologico si è rivelato di gran lunga il più rappresentativo: le statistiche di questo mercato mostrano, infatti, tendenze positive, sebbene il consumo risulti ancora eterogeneo e contenuto rispetto al consumo di alimenti convenzionali. Ciò mostra che il comportamento dei consumatori non è ancora abbastanza reattivo alle suddette politiche. Il presente studio si propone di contribuire alla ricerca sul consumo sostenibile approfondendo i fattori che incoraggiano o impediscono il consumo di prodotti alimentari biologici in Italia. Adottando un nuovo approccio si cerca di capire come i diversi segmenti di diete alimentari affrontino gli alimenti biologici in termini di consumi e di atteggiamenti. Un'analisi multivariata a più fasi è stata condotta su un campione di 3.004 consumatori. Un’analisi delle componenti principali non lineare è stata applicata alle variabili ordinali che misurano il consumo di ventuno categorie di alimenti. Successivamente è stata applicata la cluster analysis che ha dato luogo a quattro segmenti di abitudini alimentari. I prodotti biologici sono diventati parte delle abitudini alimentari in Italia in quasi un terzo della popolazione. Il consumo sembra essersi affermato soprattutto nel segmento con abitudini alimentari sane. Una scarsa attenzione ad una dieta sana, gli stili di vita, il reddito, l'accessibilità, la mancanza di consapevolezza condizionano le abitudini alimentari a scapito di un consumo più sostenibile.