Marcel Marschewski

Electron spectroscopic analysis of the human lipid skin barrier: cold atmospheric plasma-induced changes in lipid composition.

The lipids of the stratum corneum comprise the most important components of the skin barrier. In patients with ichthyoses or atopic dermatitis, the composition of the skin barrier lipids is disturbed resulting in dry, scaly, itching erythematous skin. Using the latest X‐Ray Photoelectron Spectroscopy (XPS) technology, we investigated the physiological skin lipid composition of human skin and the effects of cold atmospheric plasma treatment on the lipid composition. Skin lipids were stripped off forearms of six healthy volunteers using the cyanoacrylate glue technique, plasma treated or not and then subjected to detailed XPS analysis. We found that the human lipid skin barrier consisted of 84.4% carbon (+1.3 SEM%), 10.8% oxygen (+1.0 SEM%) and 4.8% nitrogen (+0.3 SEM%). The composition of physiological skin lipids was not different in males and females. Plasma treatment resulted in significant changes in skin barrier lipid stoichiometry. The total carbon amount was reduced to 76.7%, and the oxygen amount increased to 16.5%. There was also a slight increase in nitrogen to 6.8%. These changes could be attributed to reduced C‐C bonds and increased C‐O, C=O, C‐N and N‐C‐O bonds. The moderate increase in nitrogen was caused by an increase in C‐N and N‐C‐O bonds. Our results show for the first time that plasma treatment leads to considerable changes in the human skin lipid barrier. Our proof of principle investigations established the technical means to analyse, if plasma‐induced skin lipid barrier changes may be beneficial in the treatment of ichthyotic or eczematous skin.

Silver nano particle formation on Ar plasma – treated cinnamyl alcohol

Metastable induced electron spectroscopy, ultraviolet photoelectron spectroscopy, X-ray photoelectron spectroscopy, and atomic force microscopy are employed to study the adsorption of silver on cinnamyl alcohol films prepared on Au(111) substrates by thermal evaporation. Additionally, the impact of an Ar atmosphere dielectric barrier discharge plasma applied to the cinnamyl alcohol film preliminary to the Ag adsorption is investigated. In both cases silver nano particles with an average diameter of 9 nm are formed. These particles do not interact chemically with the underlying cinnamyl alcohol film. We do not find any influence of the preliminary Ar plasma-treatment on the adsorption behavior at all.

Mechanismen der Oberflächendesoxidation während des Vakuumlötens von Edelstählen

Das Vakuumloten von korrosions- und hitzebestandigen Edelstahlen ist eine wichtige-Fugetechnik, die unter anderem in der Produktion von Abgaskomponenten fur Kraftfahrzeuge eingesetzt wird. Die physikalischen und chemischen Vorgange, die wahrend des Lotprozesses an den Grenzflachen stattfinden, sind kaum untersucht. Mit dem Ziel, aus dem Verstandnis dieser Prozesse heraus die Lotbarkeit von Hochleistungsstahlen zu verbessern, wird ein Vergleich zwischen einem aluminiumhaltigen ferritischen Edelstahl und einem aluminiumfreien austenitischen Edelstahl gezogen. Anschliesend wird ein Ansatz zur Verbesserung der Lotfahigkeit von Edelstahlen in silandotiertem Argon-Grobvakuum vorgestellt.