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Articles 1 - 10 of 10
Full-Text Articles in Physical Sciences and Mathematics
Variation Of Superparamagnetic Properties With Iron Loading In Mammalian Ferritin, Richard B. Frankel, G. C. Papaefthymiou, G. D. Watt
Variation Of Superparamagnetic Properties With Iron Loading In Mammalian Ferritin, Richard B. Frankel, G. C. Papaefthymiou, G. D. Watt
Physics
The average blocking temperatures of ferritin molecules containing differing amounts of iron were determined by Mossbauer spectroscopy. The results imply that the magnetic anisotropy of the ferritin core particles is a function of particle volume. By addition of 57Fe to ferritin core particles it was determined that, at a given temperature within the superpara-magnetic temperature region, the “last-in” ferric ions have average relaxation times that are shorter than those of the bulk ferric ions.
Inorganic Particles Produced By Microorganisms, Richard B. Frankel
Inorganic Particles Produced By Microorganisms, Richard B. Frankel
Physics
The processes by which microorganisms, particularly bacteria, produce inorganic mineral particles are reviewed.
Structure, Morphology And Growth Of Biogenic Greigite (Fe3S4), Brigid R. Heywood, Stephen Mann, Richard B. Frankel
Structure, Morphology And Growth Of Biogenic Greigite (Fe3S4), Brigid R. Heywood, Stephen Mann, Richard B. Frankel
Physics
Several species of aquatic bacteria are known to exploit the earth's geomagnetic field as a means of directing their motion towards suitable habitats. A feature common to these bacteria is the presence of discrete intracellular magnetic inclusions, magnetosomes, aligned in chains along the long axis of the organism. The size and orientation of the individual magnetic particles imparts a permanent magnetic dipole moment to the cell which is, in turn, responsible for the magnetotactic response. In all species examined to date the magnetic particles have been found to be well-ordered, single domain, membrane-bounded crystals with reproducible, species-specific morphologies. Until recently, …
Paper Or Plastic?, Matthew J. Moelter
Redox Capacity Of Apo Mammalian Ferritin, Gerald D. Watt, Richard B. Frankel
Redox Capacity Of Apo Mammalian Ferritin, Gerald D. Watt, Richard B. Frankel
Physics
No abstract provided.
Iron Biominerals: An Overview, Richard B. Frankel
Biomineralization Of Iron Sulfides In Magnetotactic Bacteria From Sulfidic Environments, Dennis A. Bazylinski, Richard B. Frankel, Anthony J. Garratt-Reed, Stephen Mann
Biomineralization Of Iron Sulfides In Magnetotactic Bacteria From Sulfidic Environments, Dennis A. Bazylinski, Richard B. Frankel, Anthony J. Garratt-Reed, Stephen Mann
Physics
No abstract provided.
Intercellular Junctions, Motility, And Magnetosome Structure In A Multicellular Magnetotactic Prokaryote, Frank G. Rodgers, Richard P. Blakemore, Nancy A. Blakemore, Richard B. Frankel, Dennis A. Bazylinski, Denise Maratea, Christine Rodgers
Intercellular Junctions, Motility, And Magnetosome Structure In A Multicellular Magnetotactic Prokaryote, Frank G. Rodgers, Richard P. Blakemore, Nancy A. Blakemore, Richard B. Frankel, Dennis A. Bazylinski, Denise Maratea, Christine Rodgers
Physics
A many-celled, magnetotactic, prokaryote obtained from brackish water possessed intercellular connections at points of contact between the outer membranes of constituent cells. These connections structurally resembled the "gap junctions" found in eukaryotes. Each aggregate organism consisted of 10 to 30 individual gram-negative cells containing material with the appearance of poly-𝛽-hydroxybutyrate and magnetosomes of unusual arrangement, structure and composition. The aggregate, which possessed prokaryotic-type flagella arranged at the outward surfaces of each cell, showed motility indicative of coordination between individual component cells. These results suggest that this organism is a multicellular prokaryote.
Electronic Properties Of Monocapped Prismane And Basket Iron-Sulphur Clusters, B. S. Snyder, M. S. Reynolds, R. H. Holm, G. C. Papaefthymiou, R. B. Frankel
Electronic Properties Of Monocapped Prismane And Basket Iron-Sulphur Clusters, B. S. Snyder, M. S. Reynolds, R. H. Holm, G. C. Papaefthymiou, R. B. Frankel
Physics
The ground state electronic properties of the mixed-valence clusters Fe7S6 (PEt3)4Cl3 (1), Fe6S6(PEt3)4L2 [L = Cl− (2), Br− (4), I− (5) and PhS− (6)], Fe6Se6 (PEt3)4Cl2 (3) and [Fe6S6(PEt)6]1− (9), have been investigated by magnetic susceptibility, magnetization and Mössbauer spectroscopic measurements. Cluster 1 has a (idealized C3v) monocapped prismane structure and clusters 2–6 and 9 adopt the C2v “basket” configuration based on the [Fe6 …
Magnetic Fine Particles In Biological Systems, Dominic P.E. Dickson, Richard B. Frankel
Magnetic Fine Particles In Biological Systems, Dominic P.E. Dickson, Richard B. Frankel
Physics
Two examples of biological magnetic fine particles are considered: iron-storage proteins and magnetotactic bacteria. These cover many aspects of this field, including the use of well-defined biological systems for testing theoretical models, using magnetic properties to distinguish between different biological materials, producing magnetic materials by biological processes, and using optimised biological magnetic systems as a guide to the production of synthetic magnetic materials.