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Einverleibung e «organismo sociale». Modelli e metafore della relazione individuo, stato e società in Nietzsche.
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Design, synthesis and structural characterization of functional coordination polymers for storage and separation of gases of energetic and environmental relevance.
No full textThe research about new fuels, as an alternative to traditional fossil fuels, is one of the most important and pressing topics of the last decades. With this purpose, several strategies have been proposed:
the more promising ones involve the use of hydrogen and methane as energy carriers. Even if, in principle, these gases seem to be the best alternative to liquid traditional fuels, their application in stationary and mobile systems, from a practical point of view, shows some di_culties. The most important obstacle to the development of an economy based on hydrogen is the di_culty to store this gas, both because of its physical characteristics and because of its low volumetric energy density, especially if compared to that of gasoline.
In this sense, the Department of Energy of the US government has stated precise targets, for hydrogen storage and transportation parameters, that ful_ll safety and economic requirements. Among the great number of materials and methods proposed to store hydrogen and other gases of environmental interest, one of the more recent and promising one is based on MOFs (Metalorganic Open Frameworks), that is porous coordination polymers. This kind of systems is constituted by metal ions or metallic clusters connected with each other by organic ligands in order to build an open network with channels and cavities capable to include, in a selective way, guest molecules.
The work presented in this doctoral thesis _ts in a wider project of synthesis and characterization of porous coordination polymers, with the aim of obtaining materials suitable for the adsorption and separation of environmentally relevant gases. Particularly, we have studied compounds of divalent metallic ions of the _rst transition period, with polyazaaromatic ligands functionalized with carbonylic and carboxylic groups. The synthetic methods used led, in most cases, to the formation of polycrystalline products that, for this reason, have been structurally characterized by means of X-ray powder di_raction (XRPD). Therefore, the adopted structural solution method from powder di_raction data is described in details in Chapter 2, as well as other analysis techniques that have supported the de_nition of a correct structural model. With this intent, elemental and thermal analysis (TGA and DSC) have been performed on the obtained products, in order to evaluate the materials composition and their thermal stability range. Besides, the thermal behavior of the materials has been studied through thermodi_ractometric measurements, thus obtaining information about the formation of polymers and about possible phase transitions induced by the gradual heating of the studied products.
After the structural characterization of the compounds, the magnetic and adsorptive properties of the obtained materials have been studied; we have paid particular attention to the adsorption processes of nitrogen and hydrogen at 77 K and carbon dioxide and methane at 273 K. The _rst group of studied compounds includes three species, with general formula [fM(F-pymo)2gn]_2:5nH2O (M = Co, Zn, and Co0:21Zn0:79), based on the 5-uoropyrimidin-2-olate (F-pymo) ligand. In the three compounds the F-pymo ligands adopt an N,N'-exobidentate coordination mode, bridging the M(II) ions within a tridimensional sodalitic structure.
Heating the species [fM(F-pymo)2gn]_2:5nH2O (M = Co, Zn), as described in detail in Chapter 3, at _rst leads to the formation of an anhydrous sodalitic phase; further heating induces the polymorphic transformation of this phase into a bidimensional layered structure. Through this chapter the adsorption measurements results toward H2 and N2 at 77 K and CH4 et CO2 at 273 K of the thermally activated sodalitic species will be also illustrated. A \gate-opening" mechanism, together with the polar nature of the pores and with exclusion e_ects due to the di_erent dimensions of the adsorbate molecules, lead to the exclusive adsorption of CO2, starting from a speci_c \gate-pressure".
Mn(II) compounds with the pyrimidine-4,6-dicarboxylate (pmdc) ligand have been examined in Chapter 4: the variation of the synthetic conditions led to the isolation of four di_erent species, two monodimensional, one bidimensional and one porous tridimensional; a mixed iron(II) and manganese(II) compound has been also prepared, with a monodimensional polymeric structure.
The 1D compounds with formula f[Mn(_-pmdc)(H2O)3] _ 2H2Ogn, f[Mn2(_-pmdc)2(H2O)5] _ 2H2Ogn,f[FeMn(_-pmdc)2(H2O)5] _ 2H2Ogn, and the bidimensional compound f[Mn(_3-pmdc)(H2O)] _ H2Ogn, have been characterized from the point of view of the magnetic properties, showing in general an antiferromagnetic behavior; N2 adsorption measurements have con_rmed the lack of permanent porosity in these materials.
From the point of view of porous materials preparation for gas adsorption, the most relevant compound is the tridimensional one. This material, that displays a zeomimetic sodalitic structure, shows permanent porosity. Worthy of note, the anhydrous phase contains coordinatively unsaturated (square planar) Mn2+ centers, that are very unusual and could be interesting in adsorption processes and in catalysis. Adsorption measurements of N2 at 77 K and CO2 at 273 K has been interpreted in the light of this structure. The pmdc ligand has been also used in the preparation of Fe(II), Co(II), Ni(II) and Cu(II) compounds, described in Chapter 5. The obtained products, of general formula f[M(_-pmdc)(H2O)2] _ H2Ogn, at room temperature are monodimensional polymers. The study of the thermal behavior of these species showed that, when heated, at _rst they lose a water molecule, a_ording monodimensional bishydrated polymers. A further thermal treatment lead to the formation of the anhydrous phases, that are characterized by a low crystallinity. Only in the case of compound f[Cu(pmdc)]gn we have obtained information about the structural change that takes place during the thermal dehydration. During this process, the carboxylate groups deviate from coplanarity with the pyrimidinic ring, bridging the metal centers of adjacent chains and giving rise to the formation of bidimensional ordered layers. The observed conformational change of the ligands can be justi_ed by considering a Jahn-Teller distortion of the Cu(II) metal centers.
The third and last ligand presented in this thesis is the 1,3,5-triazine- 4,6-dione-2-carboxylate (Hoxonate) dianion. The compounds formed by this ligand with the Cu(II) ion are discussed in Chapter 6.
The _rst compound presented, f[Cu(Hoxonato)(H2O)]gn, is a monodimensional polymer characterized by a high thermal stability. Indeed, thermodi_ractometric studies have demonstrated that this material remains unchanged until the decomposition temperature (513 K), without losing the coordination water. The second copper(II) compound, f[Cu(Hoxonato)(4; 40-bpy)0:5] _ 1:5H2Ogn, is a tridimensional coordination polymer in which layers of [Cu(Hoxonato)]n are connected by 4,4'-bpy ligands, that act as pillars. Clathrated water molecules are hosted in isolated cavities. Even if the structural characteristics are not those of a porous compound, adsorption measurements of CO2 at 273 K have demonstrated that the system is capable to adsorb this gas in an e_cient and reversible way. This result is distinct from that obtained with CH4, of which a minimum quantity is retained at high pressure. The selectivity shown by this material motivated us to investigate its behavior in the separation of mixtures of CH4/CO2. These results are described at the end of this Chapter. The last Chapter of the thesis is dedicated to the description of Mn(II), Co(II), Ni(II) and Zn(II) compounds with the Hoxonato ligand. Also in this case the compounds containing only the Hoxonic ligand are 1D polymers, with formula f[M(Hoxonato)(H2O)2] _ H2Ogn (M = Mn, Co, Zn) and f[Ni(Hoxonato)(H2O)4]gn. By using also the 4,4'-bipyridine ligand we have instead obtained two crystalline compounds, one of Zn(II) and the other one of Ni(II): in the case of zinc the compound is bidimensional, while it was not possible to structurally characterize the species containing Ni, even if the gas adsorption and the magnetic data show that we are dealing with an extended ultramicroporous system. The latter is the only one, among the compounds presented in Chapter 7, with permanent porosity. The results presented show that the ligands used in this thesis work had an extremely versatile behavior, as it is reected in the structural diversity and in the properties of the obtained products.
The symmetric and anionic nature of the employed ligands favors the formation of extended robust systems that do not need the presence of counterions hosted in the hollows of the structure. This characteristic permits that the compounds obtained with a tridimensional framework show, in all cases, a porous structure suitable for the adsorption of probe gases of environmental interest.
The high selectivity shown in some adsorption processes opens possibilities in the use of these systems in processes of separation and catalysis of gases of industrial and environmental interest. Furthermore, we could demonstrate that it is possible to use non conventional synthetic strategies in coordination chemistry, that lead to the formation of the described compounds.
The results described in this thesis work have given rise to _ve sci-16 enti_c papers. Four of these have been already published and are collected in Appendix A while a _fth is in preparation
New anti-tumor vaccine and immunotherapeutic strategies based on optimal stimulation of CD4+ T Helper cells.
No full textVaccination with a poorly or not immunogenic tumor fails to protect the host from a subsequent challenge with the same tumor. The mechanisms underlying the failure of these tumors to sensitize therapeutic T cells are not clearly understood, but the inability of host T cells to recognize tumor has been implicated. Previous works from our laboratory have shown that the highly aggressive BALB/c mammary adenocarcinoma TS/A, can be rejected if genetically modified to express MHC class II genes upon transfection of the MHC class II transactivator CIITA. MHC class II molecules are required for presenting antigenic peptides to T helper cell and thus activate the cascade of events leading to immune effector functions such as antibody production and cytolytic T cell activity. The purpose of my thesis was to investigate whether the above approach could be generalized and thus extended to tumors of distinct histological origin. Moreover, it was assessed whether anti-tumor lymphocytes generated by this approach could be used as an immunotherapeutic tool for established cancers. Beside the previously described TS/A-CIITA breast carcinoma cells, stable CIITA-transfectants of colon adenocarcinoma C51, renal adenocarcinoma RENCA, and sarcoma WEHI-164, were generated. Tumor cells transfectants were injected in vivo and their grow kinetics and recipient’s immune response were analyzed. Tumor rejection and/or retardation of growth was found for CIITA-transfected C51 and RENCA adenocarcinomas, as well as WEHI-164 sarcoma. As for TS/A, this tumor rejection correlated mostly with the stability and the amount of CIITA-induced MHC class II expression. Interestingly, mice rejecting CIITA-transfected tumors acquired specific immunological memory, as demonstrated by resistance to challenge with untransfected parental tumors. Adoptive cell transfer experiments demonstrated that tumor immunity correlates with CD4+ and CD8+ T lymphocytes. In this thesis, it is also shown that CIITA-induced MHC class II expression on tumor cells is able to generate antitumor therapeutic T cells. Indeed, T cells from TS/A-vaccinated mice were used in an adoptive cell immunotherapy (ACT) model of established tumors. The results showed the cure at early stages and a significantly prolonged survival at later stages of tumor progression. Importantly, CD4+ T cells were clearly superior to CD8+ T cells in anti-tumor protective function. Interestingly, the protective phenotype was associated to both a Th1 and Th2 polarization of the immune effectors. Of great importance, the T cells obtained from vaccinated mice were therapeutic also without other in vitro activation passages, like treatment with anti-CD3 and IL-2, differently to some other approaches of vaccination and ACT. Furthermore, ACT induced proliferation of tumor-specific immune splenocytes in receiving mice, leading to rejection of subsequent tumor challenge or to protection from metastasis in animals having established tumors. These data support our original idea that CIITA-expressing tumor cells can act as antigen-presenting cells (APCs) for their own tumor-associated antigens to CD4+ T cells, to induce specific and potent anti-tumor responses. These results establish the general application of our tumor vaccine model. This approach let us to envisage additional applications of this strategy for producing better lymphocyte effectors for adoptive anti-tumor cell immunotherapy, particularly in those cases of tumors non-responsive to existing therapies
Miniere, cave e torbiere: dottrina e giurisprudenza tra l'unità d'Italia e il 1927.
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Study of organic and inorganic size-segregated chemical composition of different types of tropospheric aerosol.
No full textTropospheric aerosol influences several important chemical and physical processes in the troposphere, due to its high variability in terms of origin, chemical composition, size-distribution and spatial distribution. In fact local and regional, biogenic and anthropogenic, primary and secondary sources as well as long-range transport affect aerosol properties over independent regions and layers.
For these reasons organic and inorganic chemical composition at the different size ranges must be well characterized in order to understand and properly described in models the physical and chemical processes occurring in the troposphere.
The present thesis provides a detailed description of factors controlling size-segregated inorganic and organic chemical properties of different types of tropospheric aerosol. Size segregated aerosol samples were collected during the experiments performed in 2006 within the European Project MAP (Marine Aerosol Production Project, http://macehead.nuigalway.ie/map/), and during three intensive campaigns performed in 2007 and 2008 within the Italian project MIUR-AEROCLOUDS (Study of the Direct and Indirect Aerosol Effects on Climate). A chemical characterization of both water soluble and water insoluble organic fractions and water insoluble inorganic ions was accomplished.
In the framework of the Project MAP, main primary and secondary marine aerosol chemical components were investigated under clean marine conditions with relation to seasonal oceanic biological activity. Typical marine aerosol features were observed. Non sea salt sulphate (nss-SO4=) and ammonium (NH4+) dominated the submicrometer inorganic fraction, nitrate (NO3-) and sea salt are mainly distributed in the supermicrometer fraction but sea salt largely controlled the chemical composition of the supermicrometer particles. Water soluble (WSOM) and water insoluble (WIOM) organic matter mostly distributed in submicrometer particles with a large contribution. Primary organic matter (OM) resulted mostly insoluble and mainly produced by bubble bursting processes at the sea surface, as shown by Bubble Bursting experiments performed during MAP and thus indicating the prevalent secondary origin of WSOM.
The overall results clearly evidenced that concentration of the main secondary components (nss-SO4=, NH4+, WSOM, MSA) are driven by seasonality of oceanic biological productivity.
Furthermore, a new secondary component, alkylammonium salts, has been detected in marine aerosol samples. Dimethyl- (DMA+) and diethyl- (DEA+) ammonium, resulted the most abundant organic species, second only to MSA, detected in fine particles. These two species accumulate in submicrometer marine aerosol via acid-base reaction between gaseous biogenic amines and acidic sulphates. DMA+ and DEA+ show in analogy to the other biogenic secondary components, a variation in concentration clearly driven by biological activity. This result point to a potential important new source of marine SOA and atmospheric nitrogen at the global scale with a seasonal variation connected to the oceanic biological productivity.
In the framework of the project AEROCLOUDS, night-time and daytime size segregated aerosol samples were collected concurrently at the urban site of Torre Sarca (Milan), at the urban background site of Ispra (VA), at the rural site of San Pietro Capofiume (Bologna), at the mountain site of Mt. Cimone (2165 m a.s.l.) and at the urban background site of Montelibretti (Rome), during three typical patterns of the aerosol climatology in Italy:
• Aerosol accumulation in summer anticyclonic conditions (14 to18 July 2007);
• Aerosol accumulation in winter anticyclonic conditions (6 to 10 February 2008);
• Saharan dust long-range transport in spring (23 to 27 May 2007).
At the stations located within the Po basin (Milan, Ispra and San Pietro Capofiume), the main chemical aerosol components exhibited typical seasonal features observed in other highly populated and industrialized European areas. Organic compounds and nitrate maximises in winter. Sulphate exhibits higher background levels and a higher relative contribution in summer as its formation is related to photochemical activity. Sulphate and nitrate mainly occur as ammonium salts in the fine fraction as suggested by ionic balance. The winter maximum of organics, nitrate and ammonium mass concentration results in an increase in particulate matter levels due to different mechanisms which during stable atmospheric conditions occur favouring gas to
particles conversion of semi-volatile components such as ammonium nitrate and organics. The enhanced nucleation and condensation together with higher emission of fine particles accounts for a net increase of fine aerosol mass with respect to coarse mass as suggested by higher PM1/PM10 mass ratio in winter. Furthermore different diurnal cycle of boundary layer between wintertime and summertime induces differences in diurnal variation of aerosol concentration and chemical composition because in winter, when daytime mixing is very limited in height and time, the diurnal variability in aerosol mass concentration and chemical composition is less pronounced than in summer.
The night-time-daytime WSOC/TC ratio values during wintertime and summertime highlighted that higher photochemical activity enhances atmospheric oxidation processes converting biogenic and anthropogenic emissions of organic compounds into a more water soluble form and, therefore, secondary organic aerosol (SOA) formation.
At the mountain site of Mt. Cimone, differently from the Po valley stations, the daytime aerosol concentrations showed a clear seasonal pattern with the highest concentration in summer and the lowest in winter. This trend likely reflected the higher efficiency of vertical air masses transport during warmer months suggesting that daytime valley breezes and convective processes might transport polluted air masses from the regional boundary layer to the mountain site. Conversely, wintertime and night-time observations were less affected by influences from the PBL and are representative of the free tropospheric European baseline as suggested by fine aerosol chemical composition rich in sulphate and water-soluble organic compounds and poor in fine particulate nitrate and water insoluble carbonaceous compounds.
The impact of dust transport resulted in the increase in bulk aerosol mass concentration during dust transport, in the increased concentration of water soluble calcium in the coarse fraction and in the decrease in PM1/PM10 mass ratio values at all stations with respect to regional background conditions. These changes are all attributable to enrichment into coarse particles of crustal material of Saharan origin.
Furthermore we observed two chemical features indicating aerosol ageing during transport from North-African regions: the increase of WSOC contribution to TC and the
shift of nitrate size distribution in the coarse range at Mt. Cimone showing that mineral dust occurred at synoptic scale.
The impact of Saharan dust transport strongly affected total mass and chemistry of background aerosol at Mt. Cimone, while in urban and polluted sites at lower elevation, the impact on aerosol chemistry was much less pronounced even if specific markers such as calcium revealed that transport occurred
Gamma-ray and X-ray observations of GRBs: the INTEGRAL/ISRI sample and dust scattering expanding rings.
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Representing business processes: conceptual model and design methodology.
No full textIn this work we present our contributions to business processes modeling. Namely, we have undertaken a thorough analysis of the OMG standard BPMN, along with other related technologies like WS-BPEL and XPDL. Such analysis has pointed out several weaknesses that motivate our contributions. We propose a new conceptual model of BPMN called BPeX as a clear and principled way to represent and reason about business processes. We provide a three-phase design methodology to model business processes focusing on BPMN and we introduce the notion of business process normal form. We introduce also the concept of business process views and apply them to business processes access control. Finally, we provide an extension to BPMN with privacy policies. Relevant parts of BPMN conceptual model will be included as part of the forthcoming BPMN 2.0 standard
Electrophysiological characterization and drug interaction in glycine and GABA transporters.
No full textNeurotransmitter transporters are involved in various neurological disorders and are believed to be involved in the etiology of some mood disorders. Furthermore many of these molecules represent the target of therapeutical agents used in neurological pathologies or of drugs of abuse. In contrast to their medical and social relevance, the study of neurotransmitter transporters is not as advanced as the study of channels and other molecules involved in the synaptic transmission. Due to the coupling of the uptake of the substrate with transmembrane movement of the driver ion(s), whose electrochemical gradient represents the energy source of the process, most cotransporters generate electrical currents during their activity. For this reason it is possible to express the transporter RNA in heterologous systems and investigate their electric properties with electrophysiological techniques.
The electrophysiological and biophysical properties of glycine transporters GlyT1b and GlyT2a expressed in Xenopus oocytes were investigated with two electrode voltage clamp.
Integration of the transients isolated by subtraction of the traces in presence from those in absence of saturating glycine confirmed the intramembrane nature of the charge movement underlying the process. The sigmoidal Q/V relationships is much steeper for GlyT2a compared to GlyT1b, in agreement with different Na: Cl: glycine stoichiometry of the two transporters. The transient currents are best fitted by the sum of two exponentials, with the slow time constant (τslow) being larger for GlyT2a and in the order of tens of milliseconds. The apparent affinity for glycine is in the micromolar range and voltage-dependent, decreasing at positive potentials for both transporters. A simple, three-state model, is sufficient to explain the main features of GlyT1b operation, including the voltage-dependent affinity, while for GlyT2a a more complex scheme is required.
The effects of the tricyclic antidepressant imipramine on the activity of the GABA cotransporter GAT-1 have been studied with electrophysiological and confocal microscopy experiments on Xenopus oocytes transfected with GAT-1 cRNA. Imipramine at concentrations 10 – 1000 μM progressively inhibits the transient (presteady-state) currents in absence of GABA, as well as the currents associated to the neurotransmitter translocation. In contrast, the GAT-1-related uncoupled current, best seen in presence of Li+, appears to be unaffected by the drug. Redistribution studies using GAT1-GFP constructs on transfected HEK293 cells indicate no evident internalization of the transporter upon imipramine exposure. The drug also appears to inhibit a K+ M-like current endogenously present in the oocytes.
The effect of TCA on GAT-1 mutant K448E were investigated also. Lysine 448 of GAT-1 corresponds to aspartate 401 of LeuT, a residue found to be involved in the TCA binding. Desipramine is the antidepressant that shows the most powerful inhibition of transport and presteady state currents on the mutant compared to the wild type transporter. The result confirms the ability of TCAs to act on multiple targets, and the involvement of specific aminoacidic residues in substrate and inhibitor binding