Search results for "Tact"
showing 10 items of 1313 documents
Physically-Based Approach to the Mechanics of Strong Non-Local Linear Elasticity Theory
2009
In this paper the physically-based approach to non-local elasticity theory is introduced. It is formulated by reverting the continuum to an ensemble of interacting volume elements. Interactions between adjacent elements are classical contact forces while long-range interactions between non-adjacent elements are modelled as distance-decaying central body forces. The latter are proportional to the relative displacements rather than to the strain field as in the Eringen model and subsequent developments. At the limit the displacement field is found to be governed by an integro-differential equation, solved by a simple discretization procedure suggested by the underlying mechanical model itself…
The mechanically-based approach to 3D non-local linear elasticity theory: Long-range central interactions
2010
Abstract This paper presents the generalization to a three-dimensional (3D) case of a mechanically-based approach to non-local elasticity theory, recently proposed by the authors in a one-dimensional (1D) case. The proposed model assumes that the equilibrium of a volume element is attained by contact forces between adjacent elements and by long-range forces exerted by non-adjacent elements. Specifically, the long-range forces are modelled as central body forces depending on the relative displacement between the centroids of the volume elements, measured along the line connecting the centroids. Further, the long-range forces are assumed to be proportional to a proper, material-dependent, dis…
Pertussis-specific cell-mediated immunity in infants after vaccination with a tricomponent acellular pertussis vaccine.
1996
The aim of this study was to investigate pertussis-specific cell-mediated immunity in infants vaccinated with a tricomponent acellular vaccine. Infants were investigated during a primary vaccination schedule from the third month of life to the sixth month as well as before and after a booster at 15 to 24 months. This is the first report of specific cell-mediated immune responses to pertussis-related antigens in infants below the age of 12 months. Our data show that the vaccine induces T-cell responses specific for the vaccine components, detoxified pertussis toxin, filamentous hemagglutinin, and pertactin, that increase progressively over the course of the vaccination schedule. In contrast …
Comparative study of a whole-cell pertussis vaccine and a recombinant acellular pertussis vaccine.
1994
The safety and immunogenicity of an acellular pertussis vaccine containing the genetically detoxified pertussis toxin PT-9K/129C, filamentous hemagglutinin, and pertactin, together with diphtheria and tetanus toxoids, were compared with those of a whole-cell pertussis component-diphtheria-tetanus vaccine. Four hundred eighty infants were enrolled into this prospective, multicenter, double-blind study. Each infant was randomly given three doses of one of the two vaccines at 2, 4, and 6 months of age. Both local and systemic adverse reactions, reported within 48 hours and 7 days of each injection, were less frequent after the acellular vaccine than after the whole-cell vaccine. The enzyme-lin…
Halloysite nanotubes loaded with peppermint essential oil as filler for functional biopolymer film
2016
Abstract The purpose of this paper is to show how a functional bionanocomposite film with both antioxidant and antimicrobial activities was successfully prepared by the filling of a pectin matrix with modified Halloysite nanotubes (HNT) containing the essential peppermint oil (PO). Firstly, HNT surfaces were functionalized with cucurbit[6]uril (CB[6]) molecules with the aim to enhance the affinity of the nanofiller towards PO, which was estimated by means of HPLC experiments. The HNT/CB[6] hybrid was characterized by several methods (thermogravimetry, FT-IR spectroscopy and scanning electron microscopy) highlighting the influence of the supramolecular interactions on the composition, therma…
Low zone tolerance induced by systemic application of allergens inhibits TC1-mediated skin inflammation
2005
Background The induction of tolerance may be a promising target of strategies aimed at preventing harmful allergic diseases. Low zone tolerance (LZT), induced by epicutaneous application of low doses of contact allergens, inhibits the development of T C 1-mediated contact hypersensitivity (CHS). Objective We evaluated the effect of systemic (oral, intravenous) administration of low amounts of haptens on specific immune reactions and tolerance induction. Methods By using the mouse model of LZT, we analyzed immune reactions in vivo (skin inflammation) and T-cell responses in vitro after oral, intravenous, or epicutaneous application of low amounts of the contact allergen 2,4,6-trinitro-1-chlo…
Critical role of IL-10 in the induction of low zone tolerance to contact allergens
2003
The development and mechanisms of tolerance to allergens are poorly understood. Using the murine low zone tolerance (LZT) model, where contact hypersensitivity (CHS) is prevented by repeated topical low-dose applications of contact allergens, we show that LZT induction is IL-10 dependent. IL-10 is required for the generation of LZT effector cells, that is, CD8+ regulatory T cells. Only T cells from tolerized IL-10+/+ mice or IL-10-/- mice reconstituted with IL-10 during LZT induction adoptively transferred LZT to naive mice and prevented CHS, whereas T cells from IL-10-/- mice failed to do so. The IL-10 required for normal LZT development is derived from lymph node CD4+ T cells, the only sk…
Epicutaneous and Oral Low-Zone Tolerance Protects from Colitis in Mice
2016
Tolerance to environmental antigens that encounter the organism at interfaces like skin or gut prevents deleterious systemic immune responses. The aim of this study was to analyze whether and how low doses of haptens, by entry through the skin or gastrointestinal tract, affect the outcome of the predominantly Th1/Th17-mediated 2,4,6-trinitro-benzenesulfonic acid-induced colitis, which mimics an autoimmune bowl disease in man. Epicutaneous and oral applications of low doses of the allergen resulted in the induction of low-zone tolerance (LZT) and protected from colitis development, demonstrated by a significantly reduced inflammatory response of the gut in vivo. In line with this observation…
Induction of regulatory T cells by leflunomide in a murine model of contact allergen sensitivity.
2006
Allergic contact dermatitis and contact hypersensitivity (CHS) are characterized by allergen-specific activation of CD8 + and CD4 + T cells and the production of cytokines resulting in an inflammatory response and tissue damage. We show here that the immunosuppressive compound leflunomide ( N -[4-trifluoro-methylphenyl]-5-methylisoxazol-4 carboxamide, HWA 486) (LF) inhibited the contact allergic response induced in mice by epicutaneous application of the haptens dinitrofluorobenzene (DNFB) and oxazolone. The extent of ear swelling remained significantly reduced following repeated challenge with DNFB for up to 18 weeks. LF and DNFB had to be applied simultaneously for inhibition to occur. Th…
Induction of CD4+/CD25+ regulatory T cells by targeting of antigens to immature dendritic cells
2003
AbstractCoupling of ovalbumin (OVA) to anti–DEC-205 monoclonal antibody (mAb) (αDEC) induced the proliferation of OVA-specific T cells in vivo. Expansion was short-lived, caused by dendritic cells (DCs), and rendered T cells anergic thereafter. Phenotypic analysis revealed the induction of CD25+/CTLA-4+ T cells suppressing proliferation and interleukin-2 (IL-2) production of effector CD4+ T cells. The findings were supported by 2 disease models: (1) CD4+ T-cell–mediated hypersensitivity reactions were suppressed by the injection of αDEC-OVA and (2) the application of hapten-coupled αDEC-205 reduced CD8+ T-cell–mediated allergic reactions. Thus, targeting of antigens to immature DCs through …