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Nonlinear eigenvalue Neumann problems with discontinuities
No full textAbstractIn this paper we study nonlinear eigenvalue problems with Neumann boundary conditions and discontinuous terms. First we consider a nonlinear problem involving the p-Laplacian and we prove the existence of a solution for the multivalued approximation of it, then we pass to semilinear problems and we prove the existence of multiple solutions. The approach is based on the critical point theory for nonsmooth locally Lipschitz functionals
Existence of solutions for differential inclusions without convexity
No full textIn questo lavoro otteniamo due teoremi di esistenza per inclusioni
differenziali. Nel primo teorema proviamo una condizione per l'esistenza
di soluzioni del problema di Cauchy:
,
ove ``F'' è un operatore multiunivoco di
ed ``f'' è una perturbazione monodroma. Questo risultato contiene
i teoremi di esistenza conseguiti in e .
Nel secondo teorema studiamo l'esistenza di soluzioni per il problema
più generale:
ove ``G'' è una perturbazione multiunivoca.In this note we obtain two existence theorems for differential inclusions.
In the first theorem we prove a condition for the existence of solutions
to the Cauchy problem:
,
where ``F'' is multivalued operator of di
and ``f'' is a singlevalued perturbation. This result improves the
existence Theorems obtained in and .
In the second theorem we study the existence of solutions for the
more general problem:
where ``G'' is a multivalued perturbation
La K-midpoint* convessità (concavità) e la semicontinuità inferiore (superiore) di una multifunzione
No full textSolvability of Strongly Nonlinear Boundary Value Problems for Second Order Differential Inclusions
No full textIn this paper we study a problem for a second order differential
inclusion with Dirichlet, Neumann and mixed boundary conditions. The
equation is driven by a nonlinear, not necessarily homogenous,
differential operator satisfying certain conditions and containing,
as a particular case, the p-Laplacian operator. We prove the
existence of solutions both for the case in which the multivalued
nonlinearity has convex values and for the case in which it has not
convex values. The presence of a maximal monotone operator in the
equation make the results applicable to gradient systems with
non-smooth, time invariant, convex potential and differential
variational inequalities
Strongly nonlinear multivalued systems involving singular -Laplacian operators
No full textIn this paper we study two vector problems with homogeneous Dirichlet boundary conditions for second order strongly nonlinear differential inclusions involving a maximal monotone term. The first is governed by a nonlinear differential operator of the form x bar right arrow(k(t)Phi(x'))', where k is an element of C(T, IR(+)) and Phi is an increasing homeomorphism defined on a bounded domain. In this problem the maximal monotone term need not be defined everywhere in the state space R(N), incorporating into our framework differential variational inequalities. The second problem is governed by the more general differential operator of the type x bar right arrow (a(t,x)Phi(x'))', where a(t,x) is a positive and continuous scalar function. In this case the maximal monotone term is required to be defined everywhere
Analisi del programma tollerogenico delle cellule soppressorie di origine mieloide
Full text linkSUMMARY
Tumor can activate a complex network of negative control of the immune response, inducing immunological tolerance. Antitumor chemotherapy causes immunosuppression but also favours activation of immune effectors by either triggering immunogenic cancer cell death or removing immunosoppressive constraints established in the host by growing tumors. In this work we demonstrated that the antimetabolite 5-fluoruracil can reduce for a long time the number of myeloid derived suppressor cells (MDSCs) residing in the spleen. This chemothrapeutic drug does not affect directly cancer cells but perturb a biological niche shared by central memory CD8+ T cells and a population of tumor-induced, actively proliferating, immunosuppressive myeloid cells. Depletion of this niche by surgical removal completely abrogates tumor-induced tolerance.
Moreover, we began to characterize the effects of ATP on the suppressive function of MDSCs; in particularly we focused on the ATP effects mediated by P2 purinergic receptors. The preliminary data that we obtained in this study open a new prospective on a different set of metabolites that can determine the functional properties of MDSCs. This is of particular interest in cancer therapies since the extra-cellular concentration of ATP at the tumor site is abnormally elevated.RIASSUNTO
Le cellule tumorali sono in grado di modulare la reattività del sistema immunitario mediante un insieme di processi che regolano negativamente la risposta immunitaria. Questo processo è meglio noto come tolleranza immunologica. La chemioterapia antitumorale causa immunosoppressione ma favorisce anche l’attivazione di cellule effettrici del sistema immunitario sia, promuovendo la morte immunogenica delle cellule tumorali, che riducendo una componente cellulare fondamentale nella deregolazione della risposta immune indotta dal tumore. In questo lavoro abbiamo mostrato come il farmaco antimetabolita 5-fluorouracile induca un riduzione della popolazione mieloide soppressoria residente nella milza, attraverso una duratura azione che non influenza direttamente le cellule tumorali e che dipende integralmente dalla perturbazione della nicchia biologica condivisa dalle cellule CD8+ T central memory (TCM) e da un popolazione di cellule mieloidi attivate dal tumore, altamente proliferanti e dotate di una potente azione immunosoppressiva. L’eliminazione di questa nicchia mediante rimozione chirurgica della milza abroga completamente la tolleranza immunitaria indotta dal tumore.
Inoltre, allo scopo di studiare i complessi meccanismi molecolari responsabili della funzione soppressoria delle MDSC, abbiamo caratterizzato la risposta purinergica P2-mediata indotta da ATP nelle cellule mieloidi, gettando le basi per una futura e approfondita indagine degli effetti mediati da questo messaggero extracellulare presente in elevate concentrazioni nel microambiente tumorale
Heteroclinic solutions for second order non-autonomous boundary value problems on the real line
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