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T-cell proliferation on immunopathogenic mechanism of psoriasis: a control based theoretical approach

Datta A., Roy P. K.

Control and Cybernetics

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2013

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Vol. 42, no. 2

365--386

EN

Psoriasis vulgaris is a common, worldwide autoimmune skin disorder characterized by T-cells mediated hyperproliferation of keratinocytes. The feature of T-cells arbitrated psoriatic lesions is the epidermal infiltration of oligoclonal CD8+ T-cells and also of CD4+ T-cells in the dermis. Psoriatic scratches are identified by red and enlarged lesions along with silver whitish scales. In this article, we propose a mathematical model for psoriasis, involving a set of differential equations, concerning T-cells, dendritic cells and epidermal keratinocytes. We introduce T-cell proliferation in the system, where T-cells are generated through expansion of accessible CD4+ T-cells from precursors. We are interested in observing how the cell biological system develops through T-cell proliferation in presence of control with respect to T-cells and keratinocytes. We study the model in both implicit and explicit ways and measure the effect of drug on the system through impulsive drug therapy.

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The microstructure of HS 6-5-2 steel in the areas overlapping remelting obtained by the use of GTAW method

Dziedzic A.

Archives of Foundry Engineering

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2008

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Vol. 8, iss. 3

47-52

EN

The work presents microstructures of HS 6-5-2 high-speed steel from the areas overlapping remelting. The surface layer of the steel was remelted using the GTAW method. The microstructure photos were taken with LM and SEM microscopes. On microstructure photos there are visible results of heat effect overlapping remelting. The conclusions of the work show that as a result of crystallization in the zone of first remelting a system of crystals is formed which is forced the direction of heat removal from the front of the crystallization through the solid phase. With overlapping the second remelting on the first one, as a result of retreating crystallization on the border of the second and the first remelting the direction of crystals packing changes. Additionally, the heat influence zone of the second remelting changes the structure of the first remelting significantly. Aforementioned factors determine the decrease of the microhardness value of the surface layer within the areas overlapping remelting.

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Microhardness changes of surface layer of HS 6-5-2 steel in the areas overlapping remelting obtained with the use of GTAW method

Bylica A., Dziedzic A.

Archives of Foundry Engineering

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2008

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Vol. 8, iss. 3

25-28

EN

The work presents test results of microhardness of surface layer of HS 6-5-2 high-speed steel from areas overlapping remelting. The surface layer of the steel was remelted using the GTAW method. The microhardness was measured using the Vickers method. The work shows that the area, where the heat influence zone of the second remelting overlapping on the first remelting zone is characterizes by the microhardness lower about approx. 200 HV0,065.

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Microstructure of remelted zone of HS 6-5-2 high speed steel

Dziedzic A.

Archives of Foundry Engineering

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2007

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Vol. 7, iss. 3

43-46

EN

The work presents microstructures of the remelted zone of HS 6-5-2 high-speed steel. Zones of this kind can be created as a result of treating the material with a CO2 laser beam. The laser processing parameters have been chosen in such a way that the surface layer of steel remelted. The microstructures' images were taken using a scanning microscope. The tests focused on both the directional and volumetric crystallization structures. They imply that - depending on the crystallization conditions - in the remelted zone cells, dendritic cells or dendrites may be formed.