Lubrication Studies with Alumina-on-Alumina, Steel-on-Steel, and Steel-on-Alumina Bearing Systems

In metal bearing systems, good lubricants for boundary lubrication generally show chemical interaction with the bearing surface under the conditions of temperature and pressure generated in the sliding contact. In this study, tests in a four-ball wear tester have been used to compare lubricants under similar loadings using steel-on-steel, steel-on-alumina, and alumina-on-alumina bearing systems. In general, the alumina appears to be far less reactive with lubricants than steel. Alumina-on-alumina bearing systems do show a sensitivity to lubricant chemical composition with generally higher wear values than the other two bearing systems. Steel-on-alumina bearing systems generally show better wear characteristics than the all-alumina systems which indicates the improved chemical interactions between the steel and the lubricant. This study shows that the chemical reactivity of the lubricant with the bearing surface is important in the wear process.     

Plasma Lipid Peroxidation and Vitamin E Supplementation during High Intakes of Fish-Oil Fatty Acids

High intakes of fish oil concentrates (15g/day MaxEPA) resulted in increased TBARS in plasma after 2 weeks irrespective of the vitamin E intake and plasma content. After 4 weeks TBARS values returned to normal despite continued MaxEPA supplementation and different vitamin E levels. Fish oil supplements resulted in increased whole-blood aggregation and higher plasma glucose concentrations which did not occur when extra vitamin E was given. No significant differences in plasma cholesterol levels were observed.     

Localization and physical analysis of dielectric weaknesses for state-of-the-art deep trench based DRAM products

Stressed deep trench capacitors of Dynamic Random Access Memories (DRAM) were analyzed regarding the localization within a test array. A preparation method to find the position within the failing trench and to give information for process improvements is reported. Differences between the dielectrics nitride/oxide and aluminumoxide were seen. The investigations were done mostly for trench geometries of a 110nm technology. One first preparation was also successful for a 90nm technology with enlarged trench surfaces by hemispherical silicon grains ( HSG ).     

Enhanced Osteoblast Adhesion to Epoxide‐Functionalized Surfaces

As an alternative to expensive extracellular matrix (ECM) proteins generally applied as coatings in Petri dishes used for cell binding, an innovative system based on epoxide‐functionalized monolayers capable of protein binding is proposed. Since cells bind to material surfaces through proteins, protein‐binding surfaces should also promote cell binding. Here we investigate how the cell‐binding properties of an epoxide‐functionalized surface compares with ECM protein gel coated surfaces and tissue culture polystyrene control surfaces. Glass surfaces are functionalized with glycidoxypropyltriethoxysilane (GOPS), which results in an epoxide‐functionalized surface capable of binding proteins through an epoxide–amine reaction. Advancing contact angle measurements and atomic force microscopy measurements confirm the formation of a homogeneous GOPS monolayer. This monolayer is micropatterned with fluorescein‐labeled ECM protein gel by microcontact printing (µCP). Confocal laser scanning microscopy (CLSM) shows accurately transferred ECM protein gel micropatterns. Osteoblasts that are seeded on these micropatterned substrates show a clear preference for adhering to the epoxide‐functionalized areas. The morphology of these cultured osteoblasts is needle‐like with high aspect ratios. As controls, osteoblasts are cultured on GOPS‐functionalized surfaces, unstructured ECM protein gel surfaces, and tissue culture polystyrene (TCPS). The GOPS surfaces demonstrate a drastic increase in cell adhesion after 2 h, whilst the other tests show no adverse effects of this surface on the osteoblasts as compared to ECM and TCPS. CLSM shows healthy cell morphologies on each surface. It is demonstrated for the first time that epoxide groups outperform ECM protein gel in cell adhesion, thereby providing new routes for cost‐effective coatings that improve biocompatibility as well as exciting, new methodologies to control and direct cell adhesion.