W pracy podjęto próbę doboru odpowiedniego roztworu i warunków do identyfikacji stopnia uczulenia stali austenitycznej AISI 201 za pomocą metody bicyklicznej elektrochemicznej potencjokinetycznej reaktywacji (ang. double – loop electrochemical potentiokinetic reactivation test DL – EPR). Badany materiał został poddany procesowi przesycania, a następnie uczulania w temperaturze 650°C w czasie 120 minut. Do badań użyto roztworu testowego, w skład którego wchodził H2SO4 (1,0–2,0 M) oraz Na2SO4 (0,5 M). Pomiary były prowadzone w temperaturze 28°C przy szybkości skanowania 1,66 mV/s. Stopień uczulenia (S) wyznaczono przez określenie stosunku maksymalnej gęstości prądu skanowania reaktywacyjnego (Ir) do maksymalnej gęstości prądu skanowania aktywacyjnego (Ia). Najwyższą wartość S odnotowano dla roztworu 2,0 M H2SO4 + 0,5 M Na2SO4; wynosiła ona 26,13%.
EN
In the work attempts were taken to find a suitable solution and the selection of the optimal conditions for the identification of the degree of sensitization austenitic steel AISI 201 by the method of the double – loop electrochemical potentiokinetic reactivation (DL – EPR) test. The test material was given annealed and sensitized at 650°C for 120 minutes. The test solutions containing H2SO4 (1.0–2.0 M) and Na2SO4 (0.5 M) were used. Measurements were conducted at 28ºC with a scan rate of 1.66 mV / s. The degree of sensitization (S) was determined by specifying the ratio of the maximum current density scan reactivation (Ir) to the maximum current density scan activation (Ia). The highest value of the S reported for a solution of 2.5 M H2SO4 + 0.5 M Na2SO4 it was 26.13%.
Macrophages remove foreign material from the body and are recruited to sites were there are particles present. Multinucleate giant cells from by the fusion of macrophages. In the presence of particles, macrophages produce various chemical mediators, known as cytokines, as well as enzymes. Some of the cytokines are pro-inflammatory (for example, IL1Beta, IL6 and TNFalpha) while others promote giant cell formation (GM-CSF, M-CSF, TGF). The presence of these cellular products can be shown by examining tissue sections with immunohistochemistry and by western blotting. The message (mRNA) for the synthesis of these molecules can be demonstrated by in situ hybridization and the polymerase chain reaction. Macrophages process ingested material and present it as antigen to lymphocytes. Antigen-presenting macrophages play an important part in the initiation of metal sensitization. Surface receptors and their counterligands are expressed on macrophages and lymphocytes during antigen presentation. The particles present in tissues around joint prostheses have been isolated and characterized. Over 95% of these are less than 1 micron (ECD) in size. Transmission electron microscopy has revealed nanoparticles of metal in the range 15-20 nm. Such particles are too small to be phagocytosed. Hydroxyapatite, diamond-like carbon (nano-diamond) and metal particles are being studied and results compared with those of particles in the micrometer range. There is a different response to different nanoparticles.
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