Diatomées et centrifugation : évaluation des résultats par acquisition scanner

Abstract : Introduction: The diatom test is recognized as essential in forensic to diagnose drowning. However, this test still presents many biases and application issues. We are looking to improve methods the current for identifying and counting diatoms. Materials et method: On a solution loaded with diatoms, we applied two different chemical treatments: one combining the use of hydrochloric acid and heated hydrogen peroxide, and the other using sodium hypochlorite. We then centrifuged the processed solutions at different speeds and durations. After staining with methylene blue, one drop of each sample was placed and fixed on a slide. These slides were digitally scanned, then the diatoms were counted over a defined area, by differentiating between intact and fractured diatoms. Results: The use of hydrochloric acid and heated hydrogen peroxide is effective in removing impurities. A centrifugation at 500 rpm for 5 minutes is ideal for collecting as many diatoms as possible. The digitization of slides by microscopic scanning has proven to be an essential tool in the identification of diatoms. Discussion: These results have yet to be confirmed by a much larger number of samples and automated counting software for more exhaustive identification of diatoms.
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https://dumas.ccsd.cnrs.fr/dumas-02060370
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Submitted on : Thursday, March 7, 2019 - 1:13:30 PM
Last modification on : Saturday, March 30, 2019 - 2:02:17 AM
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Emma Lacaze Saint Jean. Diatomées et centrifugation : évaluation des résultats par acquisition scanner. Sciences du Vivant [q-bio]. 2019. ⟨dumas-02060370⟩

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