Biomedical subjects

Frank Marken

Publications and source records attributed to Frank Marken.

20 records · Page 2Linked to original sources

PubMed2002

An electrochemical redox couple activitated by microelectrodes for confined chemical patterning of surfaces.

Microelectrodes, printed as an array on the surface of a silicon chip, generate chemically active species in a solution of electrolyte held between the electrode array and a glass plate. The active species induce chemical change in molecules coupled to the surface of the glass plate, which is separated from the electrode array by a gap of several micrometers. This paper explores the nature and pattern of the induced chemical change. The patterning is discussed with respect to the electrolyte composition and the magnitude and duration of current applied to the microelectrodes. We show that under suitable conditions the active species is confined to micrometer-sized features and diffusion does not obscure the surface pattern produced.

Journal Article↗

PubMed2002

Voltammetric analysis of iron oxide pigments.

Eighteen earthy and four pure synthetic pigments containing alpha-Fe2O3 (hematite), alpha-FeOOH (goethite) and poorly crystalline Fe and Mn oxide species were analyzed by voltammetry of microparticles. Three natural samples were subjected to an interlaboratory test to evaluate the reproducibility of the voltammetric peak potentials and peak shapes. The results confirmed that linear-sweep voltammetry is able to distinguish between poorly crystalline, ferrihydrite-like oxides and well-crystalline hematite and goethite and to detect XRD-amorphous Mn(III,IV) oxides via the peak occurrence. Voltammetry is further able to distinguish between pigments containing well-crystalline goethite (according to its structural features) and hematite (according to its particle size). The microsamples of primers from two baroque paintings were also analyzed by XRD and voltammetry and shown to be analogous to common clayey ochres.

Journal Article↗