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Full-Text Articles in Physical Sciences and Mathematics
Genetically Encoded Phase Contrast Agents For Digital Holographic Microscopy, Arash Farhadi, Manuel Bedrossian, Justin Lee, Gabrielle H. Ho, Mikhail G. Shapiro, Jay Nadeau
Genetically Encoded Phase Contrast Agents For Digital Holographic Microscopy, Arash Farhadi, Manuel Bedrossian, Justin Lee, Gabrielle H. Ho, Mikhail G. Shapiro, Jay Nadeau
Physics Faculty Publications and Presentations
Quantitative phase imaging and digital holographic microscopy have shown great promise for visualizing the motion, structure and physiology of microorganisms and mammalian cells in three dimensions. However, these imaging techniques currently lack molecular contrast agents analogous to the fluorescent dyes and proteins that have revolutionized fluorescence microscopy. Here we introduce the first genetically encodable phase contrast agents based on gas vesicles. The relatively low index of refraction of the air-filled core of gas vesicles results in optical phase advancement relative to aqueous media, making them a “positive” phase contrast agent easily distinguished from organelles, dyes, or microminerals. We demonstrate this …
Enhancing Final Image Contrast In Off-Axis Digital Holography Using Residual Fringes, Manuel Bedrossian, Kent Wallace, Eugene Serabyn, Chris Lindensmith, Jay Nadeau
Enhancing Final Image Contrast In Off-Axis Digital Holography Using Residual Fringes, Manuel Bedrossian, Kent Wallace, Eugene Serabyn, Chris Lindensmith, Jay Nadeau
Physics Faculty Publications and Presentations
We show that background fringe-pattern subtraction is a useful technique for removing static noise from off-axis holographic reconstructions and can enhance image contrast in volumetric reconstructions by an order of magnitude in the case for instruments with relatively stable fringes. We demonstrate the fundamental principle of this technique and introduce some practical considerations that must be made when implementing this scheme, such as quantifying fringe stability. This work also shows an experimental verification of the background fringe subtraction scheme using various biological samples.
Multiwavelength Digital Holographic Imaging And Phase Unwrapping Of Protozoa Using Custom Fiji Plug-Ins, David Cohoe, Iulia Hanczarek, J. Kent Wallace, Jay Nadeau
Multiwavelength Digital Holographic Imaging And Phase Unwrapping Of Protozoa Using Custom Fiji Plug-Ins, David Cohoe, Iulia Hanczarek, J. Kent Wallace, Jay Nadeau
Physics Faculty Publications and Presentations
Multiwavelength digital holographic microscopy (DHM) has been used to improve phase reconstructions of digital holograms by reducing 2p phase ambiguities. However, most samples used as test images have been solid or adhered to a surface, making it easy to determine focal planes and correct for chromatic aberration. In this study we apply 3-wavelength off-axis DHM to swimming protozoa containing distinct spectral features such as chlorophyll and carotenoids. We reconstruct the holograms into amplitude and phase images using the angular spectrum method. Methods for noise subtraction, chromatic aberration correction, and image registration are presented for both amplitude and phase. Approaches to …
Advances In Crystallographic Image Processing For Scanning Probe Microscopy, Peter Moeck, Taylor T. Bilyeu, A. Mainzer Koenig, Jack C. Straton
Advances In Crystallographic Image Processing For Scanning Probe Microscopy, Peter Moeck, Taylor T. Bilyeu, A. Mainzer Koenig, Jack C. Straton
Physics Faculty Publications and Presentations
Brief overview of advances in image processing for scanning probe microscopes, as related to high resolution images of crystals and arrays of membrane proteins.
Nanometrology Device Standards For Scanning Probe Mmicroscopes And Processes For Their Fabrication And Use, Peter Moeck
Nanometrology Device Standards For Scanning Probe Mmicroscopes And Processes For Their Fabrication And Use, Peter Moeck
Physics Faculty Publications and Presentations
Nanometrology device standards and methods for fabricating and using such devices in conjunction With scanning probe microscopes are described. The fabrication methods comprise: (1) epitaxial growth that produces nanometer sized islands of knoWn morphology, structural, morphological and chemical stability in typical nanometrology environments, and large height-to-width nano-island aspect ratios, and (2) marking suitable crystallographic directions on the device for alignment With a scanning direction.