811 research outputs found
Libero De Libero
No full textIl contributo rende conto delle citazioni e dei riferimenti biblici presenti nell'opera di Libero De Libero
Presentazione del volume : Agostino di Ippona De gratia et libero arbitrio La grazia e il libero arbitrio. Traduzione e Introduzione di G. Balido, Editrice Domenicana Italiana, Napoli 2016
No full textIl trattato de gratia et libero arbitrio composto da Agostino nel 426-7, si inserisce a pieno titolo nei problemi che si dibattono in questi anni su problemi antropologici che sempre più di vanno infittendo coinvolgendo tematiche come grazia, libero arbitrio, tema battesimale. Problemi che coinvolgono i rapporti tra Pelagio, con i circoli pelagiani, e Agostino. Nel nostro trattato il binomio grazia-libertà trova esplicitazione attraverso tre ordini di ragioni:-la Sacra Scrittura afferma in modo inequivocabile che l’uomo è dotato di libero arbitrio;-i molteplici precetti che Dio dà all’uomo che sarebbero inspiegabili se l’uomo non fosse dotato di libero arbitrio; -il giudizio divino retribuirà ciascuno secondo le proprie opere. Il principio fondamentale della dottrina del libero arbitrio di Agostino era che esso non viene annullato dalla grazia, poiché le Scritture mostrano chiaramente che gli esseri umani possiedono una libera volontà gr. et lib. arb.: un’affermazione supportata da una lunga serie di testi biblici. Rivolgendosi ad ambiente monastico infatti richiama alla mente i passi scritturistici da cui si evince la necessità del libero arbitrio per poter adempiere ai precetti divini, che sono presentati all’uomo in maniera così manifesta da rendergli vana qualsiasi giustificazione di ignoranza per i peccati commessi.In realtà con il 426 siamo all’inizio di un fittissimo rincorrersi di opere che arrivano fino al contra Iulianum opus imperfectum del 429-430 in cui Agostino rimprovera ai pelagiani di ostinarsi a non volere ammettere la possibilità che la natura umana fosse stata mutata da peccato originale. In questi anni si susseguono dopo il de gratia et de libero arbitrio in rapida successione: il de correptione et gratia del 426 /427; il de praedestinatione sanctorum; il de dono perseverantiae (428/ 429)
Antigen-presentation of non-peptidic antigens lipid trafficking and loading
No full textT cells recognize a broad variety of antigens, including peptides, lipids and non-peptidic phosphorylated metabolites. Clarification of the rules rendering non-peptidic molecules immunogenic is essential to understand and to influence the reactions of the immune system to this class of substances in health and disease. Despite recent advances in research about immune responses to non-peptidic compounds, important issues remain unanswered. Molecular mechanisms governing the immunogenicity of non-peptidic ligands such as their cell internalization, trafficking within intracellular organelles, association with dedicated antigen-presenting molecules, induction of central and peripheral tolerance, and finally their role in autoimmune diseases as well as in protection during infections are unknown to date.
The aims of this thesis were to assess some of the immunological functions and cell biological rules governing the immunogenicity of non-peptidic antigens, with particular emphasis on cell trafficking of non-peptidic antigens and antigen-presenting molecules. It focused on (i) the antigen reactivity and presence of human invariant natural killer T (iNKT) cells in diseases, (ii) the role of CD1a trafficking in lipid antigen presentation by this protein, and (iii) the requirements of membrane translocation of phosphorylated mevalonate metabolites that stimulate human T cell receptor (TCR) gamma-delta cells.
With the development of alpha-galactosylceramide (alpha-GC)-loaded soluble CD1d dimers, which specifically interact with the TCR of iNKT cells, we have the perfect tool in our hands to perform detailed studies on iNKT cells. Analysis of the iNKT cells in blood unveiled large differences in their fluorescence intensity suggesting the presence of semi-invariant iNKT TCR with large disparities in the affinity for the alpha-GC-CD1d complex. Unexpectedly, established iNKT cell clones showed no correlation between CD1d dimer-staining levels and alpha-GC reactivity, indicating that additional mechanisms control responsiveness of iNKT cells, at least to this lipid antigen.
The identification of lipid antigens stimulating exclusively some desired functions in human iNKT cells might lead to new medical therapies or vaccines. To screen a variety of synthetic lipids for their capacity to activate iNKT cells, we devised an in vitro model based on plastic-bound CD1d. Piperidinones, molecules with a ceramide- or sphingosine-like structure, revealed that a single lipid tail is sufficient to form stimulatory complexes with CD1d. Interestingly, piperidinones preferentially induce TH1-like cytokines, predicting a possible role as novel leader molecules to functionally direct iNKT cell responses deployable in clinical therapies.
The balance of proinflammatory TH1 to regulatory TH2 cytokines is well-known to be decisive for the outcome of many diseases. Atherosclerosis (ATH) is a chronic inflammatory disease characterized by lipid accumulation in plaques. The disease is complicated by cardiovascular events provoked by plaque rupture or erosion. Because inflammation participates in lesion progression and rupture of plaques, the identification of its causes and of the culprit leukocyte populations involved in plaque destabilization is crucial for effective prevention of cardiovascular events. We used CD1d dimers to detect and characterize iNKT cells in ATH patients. We found that, in human atherosclerotic lesions, the abundance of CD1d-positive antigen-presenting cells (APC) and of iNKT cells correlates with disease severity and activity. CD1d-positive cells colonize advanced plaques in symptomatic patients and are most abundant in plaques with concomitant signs of ectopic neovascularization. In plaques, the frequency of iNKT cells among total T cells exceeds the one in blood. After having successfully isolated iNKT cell lines from plaque tissue, we showed that they promptly release proinflammatory cytokines upon lipid antigen stimulation and promote endothelial cell migration and microvascular sprout formation in vitro. This functional proangiogenic activity is ascribed to interleukin-8 released by iNKT cells after lipid recognition. These findings introduce iNKT cells as novel candidates to induce plaque neovascularization and destabilization in human ATH. Targeting iNKT cells could lead to late stage ATH treatment.
Another approach to understand the role of lipid-specific immune responses is to investigate the molecular rules of lipid-CD1 complex formation. Lipids distribute, due to their physicochemical properties or with the help of specific transporters and lipid transfer proteins, to different intracellular compartments and membrane domains. Thus, it is advantageous for the immune system to utilize multiple CD1 isoforms, each with a distinct trafficking pattern, to facilitate sampling of lipid antigens localized in various membranes. Several studies have addressed trafficking of CD1 isoforms. However, the molecular mechanisms are known in only a few cases.
We identified invariant chain (Ii) and lipid rafts as key regulators of CD1a organization on the surface of APC and of its immunological function as antigen-presenting molecule. Colocalization of CD1a with Ii is dependent on raft integrity and CD1a internalization is increased by Ii. The localization of CD1a in lipid rafts is functionally relevant as raft disruption inhibits CD1a-restricted antigen presentation.
Moreover, we found that CD1a is internalized independently of clathrin and dynamin and that it follows a Rab22a- and adenosine diphosphate ribosylation factor (ARF) 6-dependent recycling pathway, similar to other clathrin-independent cargo. Posttranslational S-acylation of the CD1a cytoplasmic tail may occur but neither determines the rate of internalization nor recycling nor its localization to detergent-resistant membrane microdomains. These findings place CD1a close to major histocompatibility complex (MHC) class I in its trafficking routes although CD1a loads lipids in recycling endosomes and not in the endoplasmic reticulum as MHC class I.
Strikingly, the glycolipid antigen sulfatide was found localized predominantly to early and recycling endosomes where CD1a is located. Swapping the cytoplasmic tail of CD1a for the one of CD1b and hence targeting the CD1a protein to the late endosomal and lysosomal compartments decreases its capacity to present sulfatide and shortens the half-life of stimulatory complexes. Thus, the physiological intracellular trafficking route of CD1a is critical for efficient presentation of lipid antigens that traffic through the early endocytic and recycling pathways.
Intracellular trafficking of another class of non-peptidic antigens, namely the phosphorylated metabolites which stimulate human TCR gamma-delta cells expressing the Vgamma9/Vdelta2 heterodimer, was examined. These T cells recognize a family of structurally related compounds produced in the eukaryotic mevalonate and prokaryotic methylerythritol phosphate (MEP) pathways. The endogenous self-ligands are generated within the cytoplasm and must cross the membrane in order to associate with dedicated antigen-presenting molecules, which remain unknown at present.
Using an in vitro transport assay, we demonstrated that the multidrug resistance-associated protein (MRP) 5 transporter is involved in membrane translocation of antigenic phosphorylated metabolites. Confocal microscopy illustrated that MRP5 is located in membranes of both endoplasmic reticulum and early endosomes. Both the intracellular localization and active role in antigen transport confer an immunological function to MRP5, resembling that of TAP (transporter associated with antigen processing) transporters involved in peptide antigen translocation. This indicates a similar strategy used for antigen presentation to TCR alpha-beta and gamma-delta T cells.
In conclusion, these studies have underlined the physiological relevance of T cells recognizing non-peptidic ligands and have revealed unanticipated molecular mechanisms controlling the efficient presentation of such antigens
Oxford Latin Dictionary, ed. P. G. W. Glare. Fase. V (libero-pactum)
No full textLeroy Maurice. Oxford Latin Dictionary, ed. P. G. W. Glare. Fase. V (libero-pactum). In: Revue belge de philologie et d'histoire, tome 56, fasc. 2, 1978. Histoire (depuis l'Antiquité) — Geschiedenis (sedert de Oudheid) p. 452
Jean Chéné et Jacques Pintard, Saint Augustin. Aux moines d'Adrumète et de Provence. De gratia et libero arbitrio. De correptione et gratia. De praedestinatione sanctorum. De dono perseverantiae
No full textPréaux Jean G. Jean Chéné et Jacques Pintard, Saint Augustin. Aux moines d'Adrumète et de Provence. De gratia et libero arbitrio. De correptione et gratia. De praedestinatione sanctorum. De dono perseverantiae. In: L'antiquité classique, Tome 32, fasc. 2, 1963. pp. 684-685
Null sets with respect to a continuous function
No full textThis short paper concerns “peso nullo” subsets of the real line defined in The framework is that of integration with respect to a function g which is continuous but not necessarily of bounded variation. Here we shall call these sets g-null. Since the family of g-null sets is a sigma-ideal, the natural question is whether it is a family of null sets with respect to a Borel measure on the real line. The paper gives a negative answer to this question
Progettazione Ottimizzata di Motori Stirling a Pistone Libero
No full textThis paper presents an analytical-numerical procedure for the study of free-piston Stirling engines. The seeking of the dynamic stability conditions is the problem here considered in more detail. The presented method allows useful "design rules" to be defined that must be satisfied in order to guarantee a correct behavior of the engine. In the reported design example, such behavior is verified by means of a code, previously developed, performing a dynamic and thermodynamic simulation.Viene presentato un procedimento analitico-numerico per lo studio di motori Stirling a pistone libero. Si affronta in particolare il problema della ricerca delle condizioni di stabilità dinamica, pervenendo a definire opportune "regole di progetto" cui tali macchine devono soddisfare per avere un corretto funzionamento a regime. Nell'esempio di progetto riportato, tale funzionamento è verificato utilizzando un codice, precedentemente sviluppato, per la simulazione dinamica e termodinamica
Groups with the basis property
No full text"The first author is supported by an EPSRC Doctoral Training Grant"We study finite groups for which every minimal generating set has the same cardinality. A group has the basis property if it and every subgroup satisfies this condition on minimal generating sets. We classify all finite groups with the basis property.Peer reviewe
Guida alla lettura del "De libero arbitrio" di Agostino
No full textIl presente lavoro ore una guida alla lettura del De libero arbitrio. In quest’opera,
composta pochi anni dopo la conversione, Agostino si interroga sulla natura e
sull’origine del male morale, mostrando come per aver fatto dono all’uomo del libero
arbitrio Dio non possa essere considerato l’autore del male compiuto attraverso di
esso. Dio, creatore e ordinatore di tutte le cose, va pertanto ritenuto non solo buono e
onnipotente, ma anche giusto.
In this work a reading guide of the De libero arbitrio is oered. In the dialogue,
shortly after his conversion, Augustine questions the nature and the origin of moral
evil, showing that God cannot be considered the author of the voluntary evil for having
given man the gift of free will. God, the creator and supreme administrator of all things,
should therefore be thought of not only as good and omnipotent, but also just
Assessment of Three Recycling Pathways for Waste Cooking Oil as Feedstock in the Production of Biodiesel, Biolubricant, and Biosurfactant: A Multi-Criteria Decision Analysis Approach
No full textThe management of waste cooking oil (WCO) often poses significant challenges. The improper disposal of WCO results in negative environmental impacts and economic losses. However, from a circular economy perspective, WCO can be recycled and used as a sustainable feedstock for numerous industrial products, replacing virgin vegetable oils. This approach enables the recovery of resources while simultaneously addressing the problem of WCO disposal. By employing a multi-criteria decision analysis (MCDA) approach, the study assesses three alternative recycling pathways for WCO used as a feedstock in the production of (A1) biodiesel, (A2) biolubricant, and (A3) biosurfactant. The aim is to identify the optimal alternative, taking into account environmental, economic, and technical factors. The procedure involved a team of chemical engineers working in the WCO recycling sector who were selected as decision makers. The ‘priority scale’ combined with the Paired Comparison Technique was employed as a weighting method to evaluate the selected criteria. The results revealed that the decision makers considered environmental sustainability as the most crucial evaluation criterion, followed by the economic criterion. In contrast, the aspect of process management was deemed less significant. Among the compared alternatives, utilizing WCO as a feedstock for biosurfactant production was assessed as the optimal WCO recycling solution. This alternative not only demonstrated the lowest coefficient variation but was also deemed the most favourable option. Biolubricant production was determined to be the second-best alternative. The adopted MCDA approach proved to be a reliable and effective tool, enabling the clear identification of the preferred WCO recycling alternative among those assessed. This was achieved through the utilization of the decision makers’ expertise and knowledge
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