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Transition metal-catalyzed alkoxylation and amination reactions involving propargyl or allyl derivatives.
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Persona e diritto nella Spagna visigota. La rielaborazione del pensiero classico sullo status libertatis nell'opera di Isidoro di Siviglia.
Full text linkThe research describes the re-elaboration of classical thought on the status personarum in the work of Isidore of Seville, with a specific focus on the status libertatis.
After a reconstruction of the context, made by a quick overview both of Visigothic Spain and of the life and works of St. Isidore, from which many legally relevant steps have been selected and translated, the analysis focuses on some basic concepts regarding freedom and slavery. It stresses their evolution, due to the revision that the Bishop of Seville performs according to his Christian faith, as well as the peculiar meaning that he assigns to certain categories, such as those of servi and famuli on one hand and ingenui, liberti and libertine on the other.
This is followed by the analysis of some passages that deal with the issues of the status civitatis, in which one can note how, always starting from the data of legal and literary tradition, the Author introduces substantial differences in accordance with his personal outlook on the world. Particularly relevant are both the associative purposes due to which St. Isidore thinks man organizes himself in societies and some key concepts, such as those of populus and plebs, peregrine and alienigena etc.
The work ends with a chapter on the status familiae, that highlights the re - interpretation, based on patristics, of the classic models of filiation and adoption.
Transversal to the three chapters are the linked concepts of pater, familia and paterfamilias
Secure information sharing on Decentralized Social Networks.
Full text linkDecentralized Social Networks (DSNs) are web-based platforms built on distributed systems (federations) composed of multiple providers (pods) that run the same social networking service. DSNs have been presented as a valid alternative to Online Social Networks (OSNs), replacing the centralized paradigm of OSNs with a decentralized distribution of the features o↵ered by the social networking platform.
Similarly to commercial OSNs, DSNs o↵er to their subscribed users a number of distinctive features, such as the possibility to share resources with other subscribed users or the possibility to establish virtual relationships with other DSN users. On the other hand, each DSN user takes part in the service, choosing to store personal data on his/her own trusted provider inside the federation or to deploy his/her own provider on a private machine. This, thus, gives each DSN user direct control of his/hers data and prevents the social network provider from performing data mining analysis over these information.
Unfortunately, the deployment of a personal DSN pod is not as simple as it sounds. Indeed, each pod’s owner has to maintain the security, integrity, and reliability of all the data stored in that provider. Furthermore, given the amount of data produced each day in a social network service, it is reasonable to assume that the majority of users cannot a↵ord the upkeep of an hardware capable of handling such amount of information.
As a result, it has been shown that most of DSN users prefer to subscribe to an existing provider despite setting up a new one, bringing to an indirect centralization of data that leads DSNs to su↵er of the same issues as centralized social network services. In order to overcome this issue in this thesis we have investigated the possibility for DSN providers to lean on modern cloud-based storage services so as to o↵er a cloudbased information sharing service. This has required to deal with many challenges. As such, we have investigated the definition of cryptographic protocols enabling DSN users to securely store their resources in the public cloud, along with the definition of communication protocols ensuring that decryption keys are distributed only to authorized users, that is users that satisfy at least one of the access control policies specified by data owner according to Relationship-based access control model (RelBAC) [20, 34]. In addition, it has emerged that even DSN users have the same difficulties as OSN users in defining RelBAC rules that properly express their attitude towards their own privacy. Indeed, it is nowadays well accepted that the definition of access control policies is an error-prone task. Then, since misconfigured RelBAC policies may lead to harmful data release and may expose the privacy of others as well, we believe that DSN users should be assisted in the RelBAC policy definition process. At this purpose, we have designed a RelBAC policy recommendation system such that it can learn from DSN users their own attitude towards privacy, and exploits all the learned data to assist DSN users in the definition of RelBAC policies by suggesting customized privacy rules.
Nevertheless, despite the presence of the above mentioned policy recommender, it is reasonable to assume that misconfigured RelBAC rules may appear in the system. However, rather than considering all misconfigured policies as leading to potentially harmful situations, we have considered that they might even lead to an exacerbated data restriction that brings to a loss of utility to DSN users. As an example, assuming that a low resolution and an high resolution version of the same picture are uploaded in the network, we believe that the low-res version should be granted to all those users who are granted to access the hi-res version, even though, due to a misconfiurated system, no policy explicitly authorizes them on the low-res picture. As such, we have designed a technique capable of exploiting all the existing data dependencies (i.e., any correlation between data) as a mean for increasing the system utility, that is, the number of queries that can be safely answered. Then, we have defined a query rewriting technique capable of extending defined access control policy authorizations by exploiting data dependencies, in order to authorize unauthorized but inferable data.
In this thesis we present a complete description of the above mentioned proposals, along with the experimental results of the tests that have been carried out so as to verify the feasibility of the presented techniques
Pythagorica medica. Scienza e sapienza nella tradizione pre-ippocratica.
No full textThe Pythagorean interest in medicine finds its natural collocation among the μαθήματα of the school, holding a privileged role. This wisdom heritage becomes a model for the σοφοί and survives throughout the centuries. Finding out its traces means reconstructing a web of cultural exchanges, particularly lively in the Greek West between the VI and IV century B.C. That’s why this research aims at pointing out some lines of persistency in the wisdom tradition, especially with regard to the field of medicine, through the guiding principles traced by the Pythagorean thought.
The enquiry starts from the wisdom and temple medicine in order to highlight its continuity with the Hippocratic tradition. The research path focuses on four archetypal topics which justify the priest skill in medical field and testify the overlap of wisdom and art of healing in ancient times. Birth, Death, Purification and Oath are four anthropological themes: studying them allows to show both the widespread and pervasive nature of the ancient medicine and the role played by the ancient Pythagoreanism.
The widespread nature of the documents, especially at the most ancient stage of the history of medicine, imposes to take into account wide historical cultural contexts and face extremely heterogeneous textual typologies which should be integrated with iconographic and archaeological data. That’s why the topic of the research needs to be analised through a multidisciplinary approach
La nozione di neutralità nella consulenza di etica clinica. The notion of neutrality in clinical ethics consultation.
No full textEthics consultation as a function performed by ethics committees, small groups of ethicists or individual consultants has developed in North America starting from the ‘70s. Despite the increasing implementation of ethics support services globally and a great deal of effort towards professionalization in the field, it is still an open question whether or not the consultant should remain neutral when her intervention is requested to address ethical conflicts and uncertainties. In particular, it is not settled whether she is allowed to express an opinion, make a recommendation or give advice.
This work is meant to analyze the notion of neutrality in ethics consultation through the critical assessment of different theoretical positions. The first chapter explains what ethics consultation is and deals with, by analyzing well-known American publications; the second explores the most common theses on the role or approach of the ethics consultant, as well as different interpretations of the terms “recommendation” and “advice”; the third focuses on the possibility and ethical acceptability of notions like ethics expertise and moral authority uncovering the main related critical positions; the last chapter offers an interpretation of the role of the consultant by considering the nature and goals of ethics consultation and it proposes four specifications of the term neutrality when it is applied: (1) to the parties involved in the consult, including the ethics consultant, (2) to the argumentations offered by the consultant to help parties make a decision, (3) to the values and norms in the case discussed, (4) to the outcome of the consultation proces
Dopaminergic modulation of phenotypical and functional characteristics of human T lymphocytes: perspectives for nonconventional immunomodulation.
Full text linkDopamine (DA) besides its action in the nervous system, plays an important role in immune cells interactions. Emerging role of DA as a regulator of CD4+ T cells physiology is important since dysregulation of different T cell subsets, showing abnormal cell numbers, functions, expression of dopamine receptors (DR) and/or response to DA, could contribute to the onset and development of some immune-related disorders. Thus, directly and indirectly acting dopaminergic therapeutics, currently used in approved clinical indications, could represent an attractive source of non-conventional agents for the modulation of CD4+ T cell functions.
The aim of the present work was to develop in vitro methods to investigate the effects of dopaminergic agents, currently used in the pharmacotherapy, on the functional responses of CD4+ T cells, namely: (i) CD4+ T naïve (Tn), T central memory (TCM) and T effector memory (TEM) cells, and their responses to recall antigen (Ag); (ii) CD4+ T regulatory cells (Treg), and their suppressive effects on T effector cells (Teff) and (iii) CD4+ T naïve cells, and their ability to differentiate towards different T helper (Th) lineages (Th1/Th2/Th17).
In cultured CD4+ T cells, our results have shown higher expression of DR in apoptotic cells in comparison to viable cells and stimulation-induced DR upregulation of all DR on viable cells. Addition of high concentrations of DA and L-DOPA (100 μM) have shown profound effect on survival of CD4+ T cells. Interestingly, based on preliminary experiments, our ex vivo data have shown trend of proliferating cells expressing DR in higher percentages that still need to be validated in subsequent studies on more subjects. So far, in vitro tested concentrations of dopaminergic agonists have not shown any major effects on proliferation of CD4+ T cells.
In addition, through the use of flow cytometric analysis, expression of DR was examined on human: CD4+ naïve T lymphocytes (CD3+CD4+CD45RA+CCR7+), TCM (CD3+CD4+CD45RA-CCR7+), TEM (CD3+CD4+CD45RA-CCR7-), Treg cells (CD4+CD25highCD127low), and also frequency of different Th subsets: Th1 (CD4+CXCR3+CCR4-CCR6-), Th2 (CD4+CXCR3-CCR4+CCR6-), Th17 (CD4+CXCR3-CCR4-CCR6+) and Th1/Th17 (CD4+CXCR3+CCR4-CCR6+) were analysed. DR expression of all five DR was confirmed on each subset, present in a different extension potentially represents an opportunity to develop targeted immunomodulating strategies.
Validated and developed in vitro method to test functional response of memory CD4+ T cells towards recall Ag have potential relevance for a wide range of different fields of T cell biology research in health and disease. Additionally, obtained preliminary results have confirmed in vitro experimental conditions likely appropriate to study commitment of naïve CD4+ T cells and factors mimicking specific polarisation routes (Th1/Th2/Th17), which are T subsets important in onset and development of some dopamine-related disorders.
Further, in vitro methods have shown CD4+CD25high T cell-dependent inhibition of CD4+ T effector lymphocyte proliferation. Treg cells also suppressed production of IFN-γ and TNF-α from Teff cells. In addition, effects of DA and L-DOPA treatments seems to suppress Treg suppressive capacity in healthy subjects and in the group of Parkinson’s disease (PD) patients who had never been treated (PD-dn), but not in PD patients that were on dopaminergic therapy (PD-dt).
Available evidence supports the possibility to repurpose dopaminergic agents as modulators of dopaminergic pathways, shifting the balance towards beneficial outcomes in some pathological conditions, such as PD. Over the last decades, an impressive number of studies in the animal model of immune diseases and in the clinical setting supported this evidence, and strongly required futher testing. The development of therapeutic protocols needs to take into account that DR exists in multiple subtypes and their patterns of expression, and that fuctional relevance differs among immune cells - and may even depend on the functional status (e.g. resting/activated) of specific cells.
Proposed in vitro methods examined and characterised the various CD4+ T cell lineages, providing both the conceptual as well as the experimental framework for more in-depth investigation of dopaminergic pathways modulating CD4+ T cell function
Clinical application of fluorescence guided surgery
No full textThe term fluorescence guided surgery (FGS) describes a medical technology based on real-time imaging intended to help and guide the surgeon during his operating practice.
In last years many innovations in surgical technique and minimally invasive technologies with laparoscopic, endoscopic and robotic techniques, has greatly improved surgical practice. Nevertheless, despite these constant advances, surgery still relies primarily on the surgeon's vision and on white-light reflectance.
The emerging field of fluorescent surgical imaging promises to be a powerful enhancement to improve surgical guidance.
Among all cromophores and fluorophores that could work as probes in medical imaging techniques, Near-infrared (NIR) fluorescence imaging with Indocyanine green (ICG) is emerging as major contributions to intraoperative surgical decisions and many different applications have already been described in literature.
ICG is a dye used in medicine since the mid-1950s for a variety of diagnostic applications in cardiology, ophthalmology and to test the hepatic clearance; however, its fluorescent properties have only recently been applied to new minimally invasive surgical instrumentations. ICG has some peculiar features that promote its widespread use: it is virtually harmless, due to lowest rate of adverse effects reported and to very high toxic dose for human body, and it is not expensive.
In addition FGS appears to have a great potential to become a standard in everyday clinical practice due to the multiple different possible applications and the ease of employ.
Our group started working on this technology since few years ago, cooperating with one of surgical imaging leading company on the market in developping new applications and tehcnical improvements.
As ICG, once injected, is excreted through the bile, it simply allows to outline the biliary tree anatomy by visualization under NIR light. This application find its ultimate use during laparoscopic cholecystectomy (LC).
LC is one of the most common procedure in general surgery worldwide (750.000 cases are performed every year in the United States); the most temible surgical complication of LC is biliary duct injuries (BDI), that could lead to severe consequences in terms of morbidity and mortality of patients. Several studies have already reported that the the primary cause of BDI is misinterpretation of biliary anatomy (71%-97% of all cases), in some cases influenced by lack of tactile feedback and anatomic variations. FGS with ICG can be used effectively in LC to visualize the biliary system and avoid injuries; to date in literature several authors published case reports or small data series on this methodic, nevertheless larger randomized controlled studies are needed to confirm and validate the potential role of this technology as gold standard for LC.
Another extremely interesting field of employment of ICG fluorescent guided surgery is intraoperative angiography; ICG injected into the bloodstream and excited by NIR light can give information about study vascular anatomy and parenchimal perfusion in various clinical situations.
Our group, at the beginning of our experience with ICG FGS, tested several possible “angiographic” applications (clarify vascular anatomy for dissection in delicate procedures or solid organ perfusion for transplants) but we decided to focus our studies on the assessment of bowel microperfusion before anastomosis creation.
Anastomotic leak (AL) is a frequent and serious complication in gastrointestinal resective surgery and adequate bowel perfusion has been stressed as one of the key elements for suture healing. Currently, there is no widespread method to assess and quantify the perfusion of gastrointestinal anastomoses intra- operatively, besides the subjective evaluation by the surgeon.
Real time intraoperative ICG fluorescent angiography (FA) is a feasible technique and a promising tool for everyday surgical practice. Nevertheless randomized controlled trials are needed to standardize technique and determine if ICG-FA might have positive impact on the AL rate in gastrointestinal anastomoses
Temporal properties of counter propagating twin photons
Full text linkTwin photon pairs generated through parametric downconversion (PDC) in a χ 2 medium is one of the most widely used source of entanglement. We focus here on a non-conventional geometry in which one of the twin photons propagates in the opposite direction with respect to the pump beam, exploiting quasi-phase-matching in a periodically poled crystal. Through predicted almost 50 years ago, this new PDC configuration has been realized experimentally only recently [1] thanks to new fabrication techniques achieving the required sub-micrometer poling period. Because of the presence of distributed feedback, the optical system has been shown to behave as a Mirrorless Optical Parametric Oscillator (MOPO) and exhibits peculiar spectral properties which strongly differ from those found in more common geometries involving co-propagating beams. In this work we provide a detailed analysis of the correlation and coherence properties of counter-propagating twin beams both in the purely spontaneous regime and in the neighborhood of the MOPO threshold. We consider on the on side the regime of spontaneous pair production where the characteristic narrow band of the counter-propagating twin beams offers the unique opportunity of generating heralded single photon states with a high degree of purity, a relevant property for applications in quantum communication. In this context, we investigate how the degree of separability of the twin photon state varies with the pump pulse duration τp. We find that two well separated time scales characterize the system dynamics: a short time scale τgvm, in the picoseconds range, corresponding to the typical temporal delay of co-propagating waves due to group-velocity mismatch, and a much longer time scale τgvs associated with the temporal separation of counter-propagating waves. Such a difference of time scales occurs naturally in the counterpropagating configuration, for basically any kind of material and tuning condition. Because of this same feature, counter-propagating twin photons in a pure state can in principle be heralded at any wavelength by choosing the appropriate poling period. We show that a high degree of separability can be achieved when the pump pulse duration satisfy the condition τgvm ≪ τp ≪ τgvs, as put in evidence from the evaluation of Schmidt number as a function of the pump pulse duration which reaches a minimum close to unity in this region. The separability is lost in the nearly monochromatic limit ( τp ≫ τgvs ) as well as for ultra-short pulses ( τp ≪ τgvm ), where the entanglement between the signal and idler frequencies can be inferred by the non factorable shape of the spectral biphoton amplitude. We offer a physical interpretation of such a behaviour, and a detailed analysis of the Schmidt number characterizing the entanglement of the state. We also considered a completely different regime of operation, close to the MOPO threshold, where the combined effect of stimulated PDC and distributed feedback affects dramatically the property of coherence of the field. Our analysis put in evidence a progressive narrowing of both the spectral twin beam correlation and the intensity spectra as the pump field intensity approaches its threshold value. This translates into a drastic increase of the correlation and coherence times in the temporal domain, a feature which can be attributed to the critical slowing down of the fluctuation dynamics characterizing the transition toward coherent emission occurring at the MOPO threshold. Furthermore, we investigate the potentiality of the source to generate squeezing and EPR type correlations in the threshold vicinity. In this regards, the obtained results shows that the system displays a behaviour which is very similar to that found in standard optical parametric oscillators enclosed in a resonant cavity. In the last part of the work, we present some preliminary results from numerical simulations illustrating the transition above the MOPO thresholds. We also take into account non collinear PDC emission, showing explicitely that the spatial and the temporal degrees of freedoms of the emitted twin photons are almost uncoupled. This feature strongly distinguish the counter-propagating configuration from standard co-propagating geometries where the phase-matching mechanism usually leads to strong angular dispersion
Synthesis and characterization of (cyclopentadienone)iron tricarbonyl complexes and their application to stereoselective catalytic transformations.
Full text linkIn recent years there has been a growing interest for developing efficient and selective homogeneous iron catalysts, thanks to the far lower cost and greater abundance of iron over the more precious metals.
During my PhD thesis, in order to improve the catalytic activities or achieve novel reactivity, we decided to modify the framework of the Knölker-type complex and to develop a small library of ten new chiral pre-catalysts, bearing a binaphthyl-derived backbone with different 3,3’-substituents, for the enantioselective hydrogenation of ketones (up to 52% ee). (Eur. J. Org. Chem., 2015, 5526-5536; Eur. J. Org. Chem., 2015, 1887-1893).
In addition to the ongoing development of chiral variants of the Knölker motif, our group was also interested in opening new vistas in catalyst design by accessing new catalyst structures easily to synthesize and with different reactivity profiles.
A new [bis(hexamethylene)cyclopentadienone]iron tricarbonyl complex was synthesized, which showed more stability and better reproducible results respect to the known Knölker-Casey catalyst underlined by TON, TOF and kinetic measurements.
Recently, we also developed a new generation of planar chiral (cyclopentadienone)iron tricarbonyl pre-catalyst, the results are promising but the research is still under investigation
Synthesis, structural characterization and functional properties of metal-organic frameworks based on poly(azolate) ligands.
Full text linkIn the firsts two Chapters, a brief introduction on the history of MOFs (Chapter 1), on the features of azolato- and poly(azolato)-based organic linkers and on the properties of fluorine and organofluorine compounds (Chapter 2) is exposed.
In Chapter 3 the synthesis of six new non-fluorinated and fluorinated poly(pyrazolato)-, poly(tetrazolato)-, and tetrazolato-derivatives is described. Each linker has been designed for the specific application to be tested.
In Chapter 4 the synthesis and characterization of a series of fluorinated and non fluorinated poly(pyrazolato)- poly(tetrazolato)-, and tetrazolato-based MOFs and N-PCPs are presented. The dielectric and CO2 adsorption properties of these new compounds have been investigated. In this context, the well known FMOF-1, has been successfully added to these compounds as a potential low- dielectric material.
The synthesis and characterization of the first two Zn(II)-based MOFs ever used as molecular and dipolar rotors is presented in Chapter 5. The investigation on the rotational speed of their aromatic core has been performed with solid state NMR studies.
Finally, using four known poly(pyrazolato)-based MOFs, we have tested their catalytic activity in the selective oxidation of hydroxymethylfurfural to diformylfuran. More important, we have disclosed the catalytic mechanism by means of DRIFT and in vacuo FT-IR spectroscopy. All the FT-IR measurements and catalytic results are discussed in Chapter 6