Surface modification and corrosion properties of implanted and DLC coated stainless steel by plasma based ion implantation and deposition

The aim of this investigation was to find a suitable pretreatment for the subsequent deposition of DLC films on a steel substrate. The implantation should on the one hand improve the corrosion properties of the steel substrate and on the other hand increase the adhesion of the DLC film to the substrate. Three different gases (oxygen, nitrogen, ethylene) were used for the implantation (voltage pulses of -10 kV), and the deposition (-15 kV) was performed with C2H4 on stainless steel substrates and silicon wafer by plasma based ion implantation and deposition (PBII&D). The influence of the different implantation gases on the composition, structure and corrosion resistance of the surface was studied. The surface morphology was changed depending on the working gas. In all implantation samples a composition gradient layer in the surface was confirmed by measurement of the depth distribution by SIMS and XPS. The DLC films as prepared with C2H4 PBII&D exhibited roughness, hardness, and friction properties similar to those of DLC films prepared by other hydrocarbon gases. The corrosion protection potential in an aqueous environment was evaluated by cyclic voltammetry. The oxygen and nitrogen implantations improved the corrosion protection properties. These two pretreatments also exhibited a good corrosion protection in combination with the DLC film coatings. This is due to the resulting bonding states in the implanted surface and due to an increased adhesion of the DLC films to the substrates as could be seen after the corrosion tests

Bioactive phytochemicals and their bioaccessibility in four unexploited tropical fruits grown in Queensland, Australia

Tropical fruits are a popular target for health-conscious consumers worldwide. The phytochemical composition, in particular polyphenols and carotenoids, of these “exotics” is of emerging interest due to the potential health benefits of these compounds. The anthocyanin, quercetin glycoside and carotenoid composition in hog plum (Spondia dulcis), peanut butter fruit (Bunchosia armeniaca), chupa-chupa (Martisia cordata) and kwai muk (Artocarpus hypargyreus) grown in North Queensland was determined in the present study. Additionally, the release/ bioaccessibility of the determined phytochemicals as an initial measure to predict their availability for intestinal absorption was assessed using an in-vitro digestion model. Six anthocyanins could be identified in Kwai muk with cyanidin-3-glucoside as the predominant pigment (80% of total amount). Quercetin glycosides ranged between 5.6 and 8.4 mg 100 g-1 fresh weight (fw). Lycopene was identified as the main carotenoid in peanut butter fruit (21.3 mg 100 g-1 fw), whereas β-carotene was predominant in chupa-chupa (5.84 mg 100 g-1 fw), kwai muk (1.66 mg 100 g-1 fw) and hog plum (0.21 mg 100 g-1 fw). The lycopene content in peanut butter fruit was considerable and even higher than that reported for tomatoes, a popular dietary source of lycopene. Total anthocyanins (10.5 mg 100 g-1 fw) and quercetin glycosides were in the same range as reported for other fruits such as gooseberries, red currants and blueberries. Between 1-3% of carotenoids, 7-25% of quercetin glycosides and 37% of anthocyanins were released/bioaccessible after the in vitro digestion procedure. The observed low release of carotenoids from unprocessed fruits is in the same range as reported for unprocessed carrots. However, processing (e.g., blending, thermal treatment) and the addition of lipids can significantly increase the release/bioaccessibility of these lipophilic compounds. The present study clearly identified peanut butter fruit as a promising candidate for follow-up studies, in vitro and in vivo, evaluating its potential as a novel dietary source of lycopene

Preparation of Ag-containing diamond-like carbon films on the interior surface of tubes by a combined method of plasma source ion implantation and DC sputtering

Adhesive diamond-like carbon (DLC) films can be prepared by plasma source ion implantation (PSII), which is also suitable for the treatment of the inner surface of a tube. Incorporation of a metal into the DLC film provides a possibility to change the characteristics of the DLC film. One source for the metal is DC sputtering. In this study PSII and DC sputtering were combined to prepare DLC films containing low concentrations of Ag on the interior surfaces of stainless steel tubes. A DLC film was deposited using a C2H4 plasma with the help of an auxiliary electrode inside of the tube. This electrode was then used as a target for the DC sputtering. A mixture of the gases Ar and C2H4 was used to sputter the silver. By changing the gas flow ratios and process time, the resulting Ag content of the films could be varied. Sample characterizations were performed by X-ray photoelectron spectroscopy, secondary ion mass spectrometry, atomic force microscopy and Raman spectroscopy. Additionally, a ball-on-disk test was performed to investigate the tribological properties of the films. The antibacterial activity was determined using Staphylococcus aureus bacteria. (C) 2014 Elsevier B.V. All rights reserved

PTPIP51: A New Interaction Partner of the Insulin Receptor and PKA in Adipose Tissue

Aims. Our previous experiments revealed an association of PTPIP51 (protein tyrosine phosphatase interacting protein 51) with the insulin signalling pathway through PTP1B and 14-3-3beta. We aimed to clarify the role of PTPIP51 in adipocyte metabolism. Methods. Four groups of ten C57Bl/6 mice each were used. Two groups were fed a standard diet; two groups were fed a high-fat diet. Two groups (one high-fat diet and one standard diet) were submitted to endurance training, while the remaining two groups served as untrained control groups. After ten weeks, we measured glucose tolerance of the mice. Adipose tissue samples were analyzed by immunofluorescence and Duolink proximity ligation assay to quantify interactions of PTPIP51 with either insulin receptor (IR) or PKA. Results. PTPIP51 and the IR and PTPIP51 and PKA, respectively, were colocalized in all groups. Standard diet animals that were submitted to endurance training showed low PTPIP51-IR and PTPIP51-PKA interactions. The interaction levels of both the IR and PKA differed between the feeding and training groups. Conclusion. PTPIP51 might serve as a linking protein in adipocyte metabolism by connecting the IR-triggered lipogenesis with the PKA-dependent lipolysis. PTPIP51 interacts with both proteins, therefore being a potential gateway for the cooperation of both pathways