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C Saloma

Publications and source records attributed to C Saloma.

5 recordsLinked to original sources
PubMed2001

Solving N-body problems with neural networks.

We show a new approach for solving the N-body problems based on neural networks. Without loss of generality, we derived a network solution for the time-dependent positions of N bodies in self-gravitating systems. The simulation is limited to a system of collisionless disks-a case for determining the spatial distributions of dark matter and in reproducing global effects such as formation of spiral galaxies. Our approach yields a solution that is analytic with time-reversed path-tracing capabilities that could lead to new findings in the study of the collective behavior of N-body systems.

Journal Article↗
PubMed2000

Long-depth imaging of specific gene expressions in whole-mount mouse embryos with single-photon excitation confocal fluorescence microscopy and FISH.

Long-depth imaging of specific gene expression in the midgestation whole-mount mouse embryo (WME) is demonstrated with single-photon excitation (1PE) confocal fluorescence microscopy and fluorescence in situ hybridization. Expression domains of Pax-6 mRNA transcripts were labeled with an in situ hybridization probe that is a RNA sequence complementary to the cloned gene fragment and were rendered visible using two fluorochrome-conjugated antibodies that fluoresce at peak wavelengths of lambda(F) = 0.525 microm and lambda(F) = 0. 580 microm, respectively. Distributions of Pax-6 mRNA domains as deep as 1000 microm in the day 9.5 WME were imaged with a long-working-distance (13.6 mm) objective lens (magnification 5x). The scattering problem posed by the optically thick WME sample is alleviated by careful control of the detector pinhole size and the application of simple but fast postdetection image enhancement techniques, such as space and wavelength averaging to produce high-quality fluorescence images. A three-dimensional reconstruction that clearly shows the Pax-6 mRNA expression domains in the forebrain, diencephalon, optic cup, and spinal cord of the day 9.5 WME is obtained. The advantages of 1PE confocal fluorescence imaging over two-photon excitation fluorescence imaging are discussed for the case of long-depth imaging in highly scattering media. Imaging in midgestation WMEs at optical depths of more than 350 microm has not yet been realized with two-photon fluorescence excitation.

Animals↗
PubMed1998

Site-specific confocal fluorescence imaging of biological microstructures in a turbid medium.

Normally transparent biological structures in a turbid medium are imaged using a laser confocal microscope and multiwavelength site-specific fluorescence labelling. The spatial filtering capability of the detector pinhole in the confocal microscope limits the number of scattered fluorescent photons that reach the photodetector. Simultaneous application of different fluorescent markers on the same sample site minimizes photobleaching by reducing the excitation time for each marker. A high-contrast grey-level image is also produced by summing confocal images of the same site taken at different fluorescence wavelengths. Monte Carlo simulations are performed to obtain the quantitative behaviour of confocal fluorescence imaging in turbid media. Confocal images of the following samples were also obtained: (i) 15 microm diameter fluorescent spheres placed 1.16 mm deep beneath an aqueous suspension of 0.0823 microm diameter polystyrene latex spheres, and (ii) hindbrain of a whole-mount mouse embryo (age 10 days) that was stained to fluoresce at 515 nm and 580 nm peak wavelengths. Expression of RNA transcripts of a gene within the embryo hindbrain was detected by a fluorescence-based whole-mount in situ hybridization procedure that we recently tested.

Animals↗