Tran Mai Thi
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PreprintMapping birefringence in three dimensions using polarized light field microscopy : the case of the juvenile clamshell( 2018-05) Tran, Mai Thi ; Oldenbourg, RudolfWe report methods to generate three dimensional maps of birefringence, its position and orientation in juvenile shells of the Atlantic hard clamshell (Mercenaria mercenaria). For measuring the retardance and optic axis orientation of curved shell surfaces in three dimensions, we developed enhanced acquisition and processing algorithms and combined results from conventional and light field imaging approaches to reconstruct the three dimensional shell shape and its anisotropic optical properties. Our work represents the first successful attempt to generate such maps at a spatial resolution of about 2 m and angular steps of about 9° in terms of the inclination angles of the optic axis. The maps of clamshell birefringence provide structural insights into the early mineralization during juvenile clamshell development.
ArticlePostnatal structural development of mammalian basilar membrane provides anatomical basis for the maturation of tonotopic maps and frequency tuning(Nature Research, 2021-04-07) Tani, Tomomi ; Koike-Tani, Maki ; Tran, Mai Thi ; Shribak, Michael ; Levic, SnezanaThe basilar membrane (BM) of the mammalian cochlea constitutes a spiraling acellular ribbon that is intimately attached to the organ of Corti. Its graded stiffness, increasing from apex to the base of the cochlea provides the mechanical basis for sound frequency analysis. Despite its central role in auditory signal transduction, virtually nothing is known about the BM’s structural development. Using polarized light microscopy, the present study characterized the architectural transformations of freshly dissected BM at time points during postnatal development and maturation. The results indicate that the BM structural elements increase progressively in size, becoming radially aligned and more tightly packed with maturation and reach the adult structural signature by postnatal day 20 (P20). The findings provide insight into structural details and developmental changes of the mammalian BM, suggesting that BM is a dynamic structure that changes throughout the life of an animal.
ArticlePoint spread function of the polarized light field microscope(Optica, 2022-05-26) Tran, Mai Thi ; Oldenbourg, RudolfWe examined the point spread function of the polarized light field microscope and established a computational framework to solve the forward problem in polarized light field imaging, for the purpose of furthering its use as a quantitative tool for measuring three-dimensional maps of the birefringence of transparent objects. We recorded experimental polarized light field images of small calcite crystals and of larger birefringent objects and compared our experimental results to numerical simulations based on polarized light ray tracing. We find good agreement between all our experiments and simulations, which leads us to propose polarized light ray tracing as one solution to the forward problem for the complex, nonlinear imaging mode of the polarized light field microscope. Solutions to the ill-posed inverse problem might be found in analytical methods and/or deep learning approaches that are based on training data generated by the forward solution presented here.