Navegando por Autor "Dasari, Ramachandra Rao"

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    Label-free route to rapid, nanoscale characterization of cellular structure and dynamics through opaque media.
    (2013) Joshi, Bipin; Barman, Ishan; Dingari, Narahara Chari; Cardenas, Nelson; Soares, Jaqueline dos Santos; Dasari, Ramachandra Rao; Mohanty, Samarendra
    We report a novel technique for label-free, rapid visualization of structure and dynamics of live cells with nanoscale sensitivity through traditionally opaque media. Specifically, by combining principles of near-infrared (NIR) spectroscopy and quantitative phase imaging, functional characterization of cellular structure and dynamics through silicon substrates is realized in our study. We demonstrate the efficacy of the new approach by full-field imaging of erythrocyte morphology in their native states with a nm path length sensitivity. Additionally, we observe dynamic variations of human embryonic kidney cells, through a silicon substrate, in response to hypotonic stimulation with ms temporal resolution that also provides unique insight into the underlying biophysical changes. The proposed technology is fundamentally suited for high-performance investigations of biological specimens and significantly expands the options for visualization in complex microfluidic devices fabricated on silicon.
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    Raman spectroscopic sensing of carbonate intercalation in breast microcalcifications at stereotactic biopsy.
    (2015) Sathyavathi, R.; Saha, Anushree; Soares, Jaqueline dos Santos; Spegazzini, Nicolas; McGee, Sasha; Dasari, Ramachandra Rao; Fitzmaurice, Maryann; Barman, Ishan
    Microcalcifications are an early mammographic sign of breast cancer and frequent target for stereotactic biopsy. Despite their indisputable value, microcalcifications, particularly of the type II variety that are comprised of calcium hydroxyapatite deposits, remain one of the least understood disease markers. Here we employed Raman spectroscopy to elucidate the relationship between pathogenicity of breast lesions in fresh biopsy cores and composition of type II microcalcifications. Using a chemometric model of chemical-morphological constituents, acquired Raman spectra were translated to characterize chemical makeup of the lesions. We find that increase in carbonate intercalation in the hydroxyapatite lattice can be reliably employed to differentiate benign from malignant lesions, with algorithms based only on carbonate and cytoplasmic protein content exhibiting excellent negative predictive value (93–98%). Our findings highlight the importance of calcium carbonate, an underrated constituent of microcalcifications, as a spectroscopic marker in breast pathology evaluation and pave the way for improved biopsy guidance.