5 research outputs found

    Raman chemical imaging, a new tool in kidney stone structure analysis: Case-study and comparison to Fourier Transform Infrared spectroscopy

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    <div><p>Background and objectives</p><p>The kidney stone’s structure might provide clinical information in addition to the stone composition. The Raman chemical imaging is a technology used for the production of two-dimension maps of the constituents' distribution in samples. We aimed at determining the use of Raman chemical imaging in urinary stone analysis.</p><p>Material and methods</p><p>Fourteen calculi were analyzed by Raman chemical imaging using a confocal Raman microspectrophotometer. They were selected according to their heterogeneous composition and morphology. Raman chemical imaging was performed on the whole section of stones. Once acquired, the data were baseline corrected and analyzed by MCR-ALS. Results were then compared to the spectra obtained by Fourier Transform Infrared spectroscopy.</p><p>Results</p><p>Raman chemical imaging succeeded in identifying almost all the chemical components of each sample, including monohydrate and dihydrate calcium oxalate, anhydrous and dihydrate uric acid, apatite, struvite, brushite, and rare chemicals like whitlockite, ammonium urate and drugs. However, proteins couldn't be detected because of the huge autofluorescence background and the small concentration of these poor Raman scatterers. Carbapatite and calcium oxalate were correctly detected even when they represented less than 5 percent of the whole stones. Moreover, Raman chemical imaging provided the distribution of components within the stones: nuclei were accurately identified, as well as thin layers of other components. Conversion of dihydrate to monohydrate calcium oxalate was correctly observed in the centre of one sample. The calcium oxalate monohydrate had different Raman spectra according to its localization.</p><p>Conclusion</p><p>Raman chemical imaging showed a good accuracy in comparison with infrared spectroscopy in identifying components of kidney stones. This analysis was also useful in determining the organization of components within stones, which help locating constituents in low quantity, such as nuclei. However, this analysis is time-consuming, making it more suitable for research studies rather than routine analysis.</p></div

    Raman mapping of sample 3.

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    <p>Raman mapping of the calcium oxalate dihydrate (A), calcium oxalate monohydrate (B) and apatite (C) and their correspondent Raman spectra. Step size: 50 ÎĽm. The yellow to dark blue scale represents the high density of a component or its absence. The peripheral spikes of the stones are mainly made of calcium oxalate dihydrate, while its center has turned into calcium oxalate monohydrate.</p

    Raman mapping of sample 9.

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    <p>Raman mapping of whitlockite (A), calcium oxalate dihydrate (B), apatite (C), and brushite (D). Step size: 50 ÎĽm. The yellow to dark blue scale represents the high density of a component or its absence. The core of the stone was absent and provided low signal. The rest of the stone was made of whitlockite and apatite, probably due to former urinary tract infection, while the brushite coat is associated to recent hypercalciuria.</p

    sj-docx-1-asp-10.1177_00037028231201653 - Supplemental material for In-Field Implementation of Near-Infrared Quantitative Methods for Analysis of Medicines in Tropical Environments

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    Supplemental material, sj-docx-1-asp-10.1177_00037028231201653 for In-Field Implementation of Near-Infrared Quantitative Methods for Analysis of Medicines in Tropical Environments by Christelle Ange Waffo Tchounga, Djang’eing’a Marini, Emmanuel Nnanga Nga, Patient Ciza Hamuli, Rose Ngono Mballa, Philippe Hubert, Eric Ziemons and Pierre-Yves Sacré in Applied Spectroscopy</p
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