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Magnetite is both a common inorganic rock-forming mineral and a biogenic product formed by a diversity of organisms. Magnetotactic bacteria produce intracellular magnetites of high purity and crystallinity (magnetosomes) arranged in linear chains of crystals. Magnetosomes and their fossils (magnetofossils) have been identified using transmission electron(More)
Transmission electron microscopy studies have been used to argue that magnetite crystals in carbonate from Martian meteorite ALH84001 have a composition and morphology indistinguishable from that of magnetotactic bacteria. It has even been claimed from scanning electron microscopy imaging that some ALH84001 magnetite crystals are aligned in chains.(More)
Distinct morphological characteristics of magnetite formed intracellularly by magnetic bacteria (magnetosome) are invoked as compelling evidence for biological activity on Earth and possibly on Mars. Crystals of magnetite produced extracellularly by a variety of bacteria including Geobacter metallireducens GS-15, thermophilic bacteria, and psychrotolerant(More)
Manganese oxide (Mn oxide) minerals from bacterial sources produce electron paramagnetic resonance (EPR) spectral signatures that are mostly distinct from those of synthetic simulants and abiogenic mineral Mn oxides. Biogenic Mn oxides exhibit only narrow EPR spectral linewidths (∼500 G), whereas abiogenic Mn oxides produce spectral linewidths that are 2-6(More)
For the purpose of in-situ plancatry exploration, such as chemical characterization of Martian surface materials by miniature instruments,. we have ,diveloped T-miniature Magnetic Resonanoe Spectrometers (MRS) namely, Nuclear Magnetic Resonanee (NMR) and Ekctron Paramagnetic Resonanee (H'R) spectrometers at JPL. They are; Proton-NMR spectrometer for the(More)
and Space Administration (grant # 1248565). We would like to thank Dr. Soon Sam Kim for having given us an opportunity to work on this project and for his continued interest in our research. We would like to thank Dr. Pannirselvam Kanagaratnam of the RSL lab for his kind help. We also acknowledge and thank the students and faculty of RSL and ITTC for their(More)
This paper presents a method to improve the contrast of digital X-ray image using CUDA program on a GPU. The histogram is commonly used to get the statistical distribution of the contrast in image processing. To increase the visibility of the image in real time, we use the histogram stretching function. It is difficult to implement the function on a GPU(More)
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