o the optical axis by the numerical aperture of condenser and objective lenses. The missing angle produces an artifact, which can be suppressed by regularization techniques using various kinds of a priori knowledge. For example, we have shown that the positivity constraint can suppress the missing cone artifact by generating new data in the missing region . We are developing an algorithm that can further suppress the missing cone artifact and increase the accuracy of refractive index prediction.
Long-term observation of biological specimens is critical in many applications including cell cycle studies and monitoring the role of various chemicals inducing such effect as apoptosis in cancer cells. Label-free and 3-D imaging capability of TPM makes it highly appropriate for long-term observation of biological specimens because it is free from artifacts of the exogenous agents, which are invasive, and experience the problem of non-uniform binding and temporal degradation of signals. By installing a live-cell chamber, we are trying to develop an on-stage culture system that can be used for the tomographic phase microscopy. In addition, we are trying to speed up the data acquisition to minimize photo-induced damage on the biological specimen. This will extend the applicability of the instruments from observing the structure of biological specimens to studying their activities.
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- Lue, N; Choi, W; Popescu, G; Badizadegan, K; Dasari, RR; Feld, MS, "Synthetic aperture tomographic phase microscopy for 3D imaging of live cells in translational motion", OPTICS EXPRESS, vol. 16, (2008), p. 16240., "
- Choi, W; Yu, CC; Fang-Yen, C; Badizadegan, K; Dasari, RR; Feld, MS, "Field-based angle-resolved light-scattering study of single live cells", OPTICS LETTERS, vol. 33, (2008), p. 1596., "
- Park, YK; Diez-Silva, M; Popescu, G; Lykotrafitis, G; Choi, WS; Feld, MS; Suresh, S, "Refractive index maps and membrane dynamics of human red blood cells parasitized by Plasmodium falciparum", PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, vol. 105, (2008), p. 13730., "10.1073/pnas.080610010 "
- Choi, W; Fang-Yen, C; Badizadegan, K; Oh, S; Lue, N; Dasari, RR; Feld, MS, "Tomographic phase microscopy", NATURE METHODS, vol. 4 (9), (2007), p 717.,"