Refractive Index Tomogram
Refractive Index Tomogram - Related Videos
13:59
Reflection and Refraction
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2023
Source: Derek Wilson, Asantha Cooray, PhD, Department of Physics & Astronomy, School of Physical Sciences, University of California, Irvine, CA Light travels at different speeds depending on the material through which it is propagating. When light travels from one material to another, it will either slow down or speed up. In order to conserve energy and momentum, the light must change the direction in which it propagates. This bending of light is known as refraction. Some fraction of the...
09:54
Fabrication of Refractive-index-matched Devices for Biomedical Microfluidics
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Cited by 6 •
2018
This protocol describes the fabrication of microfluidic devices from MY133-V2000 to eliminate artifacts that often arise in microchannels due to the mismatching refractive indices between microchannel structures and an aqueous solution. This protocol uses an acrylic holder to compress the encapsulated device, improving adhesion both chemically and mechanically.
05:36
Subjective Refraction Test Using a Smartphone for Vision Screening
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Cited by 1 •
2024
This paper presents the protocols and clinical validation data for using a smartphone app to subjectively measure refractive error.
10:25
Deep Learning-Based Segmentation of Cryo-Electron Tomograms
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Cited by 53 •
2022
This is a method for training a multi-slice U-Net for multi-class segmentation of cryo-electron tomograms using a portion of one tomogram as a training input. We describe how to infer this network to other tomograms and how to extract segmentations for further analyses, such as subtomogram averaging and filament tracing.
01:26
Influence of Earth's Curvature and Atmospheric Refraction on Leveling
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2025
During leveling, the Earth's curvature and atmospheric refraction introduce deviations in the line of sight from a true horizontal reference. When the line of sight is leveled, it remains perpendicular to the plumb line only at a single point. Beyond this, it deviates due to the Earth’s curvature, represented by the correction C. For a sight distance D, the deviation can be derived using the relationship:This relationship shows that the deviation increases quadratically with distance. Over a...
FAQs
Each illumination angle produces transmitted or scattered-light information from a different perspective. Combining these measurements gives the computational reconstruction more information about the specimen’s internal refractive-index distribution than a single view could provide. This angular sampling is therefore central to resolving three-dimensional differences in cellular structure and supporting quantitative comparisons between experimental conditions.
Spatial variations in refractive index can indicate differences in cellular structure and composition, including changes in morphology, dry mass, and intracellular organization. In immunology and infection studies, these features may shift when immune cells become activated or when pathogens invade host cells. The resulting map connects measurable optical properties with cell-level structural phenotypes.
This approach provides label-free structural information, so measurements do not depend on fluorescent tags to reveal cellular changes. That distinction is useful when researchers want to observe morphology, dry mass, or intracellular organization without introducing labeling steps. Fluorescence-based or other molecular assays can then complement, rather than replace, the structural information obtained from the tomogram.
The workflow begins by measuring light transmitted through or scattered by the specimen under multiple illumination angles. Those measurements are then supplied to a computational reconstruction procedure that estimates the three-dimensional refractive-index distribution. Researchers can analyze the resulting map for structural, compositional, morphological, dry-mass, and intracellular-organization changes relevant to the experimental question.
Researchers can use the maps to examine cell-level changes associated with immune activation or pathogen invasion. Observable outcomes include altered morphology, dry mass, and intracellular organization, all measured without fluorescent labels. This makes the technique useful for connecting host or pathogen-related biochemical changes with structural phenotypes in individual cells.
Repeated label-free measurements can support longitudinal analysis of host-pathogen interactions, allowing structural changes to be followed over time rather than assessed at only one endpoint. When combined with molecular assays, the tomograms help relate biochemical findings to cellular organization and morphology. This paired perspective can clarify how infection-associated or immune-related changes develop.