40 research outputs found

    The use of Invos™ somatic oximetry to measure variations in placental tissue oxygenation in laboring healthy term parturients with epidural analgesia: an observational study

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    Christian Loubert,1 Mélissa Ouellette,2 Valérie Zaphiratos,1 Issam Tanoubi1 1Department of Anesthesia, Maisonneuve-Rosemont Hospital, CIUSSS-de-l’Est de l’île de Montréal, University of Montreal, Montreal, 2Department of Anesthesia, Saint-Jerôme Hospital Center, CISSS des Laurentides, Saint-Jerôme, QC, Canada Purpose: Near-infrared spectroscopy provides a non-invasive continuous real-time monitoring of tissue oxygen saturation. As uterine contractions during labor may be associated with a transient uteroplacental hypoperfusion, this prospective, observational study investigates the ability of near-infrared spectroscopy to detect variation in uteroplacental oximetry during uterine contractions. Patients and methods: Four Invos™ oximetry probes (Medtronic®, Minneapolis, MN, USA) per subjects were applied on the placental surface (PLA), the abdomen (MYO), the forearm (ARM) and the leg (LEG), of twenty healthy laboring parturients with epidural analgesia. Measurements of mean tissue oxygen saturation and area under the curve (AUC) were made during 60 minutes. The primary outcome was the difference of the AUC measurements between the PLA probe and the MYO probe. Results: The AUC values for the PLA and MYO probes were not different. The mean saturation values recorded by the PLA probe were not different from the other probes. Conclusion: The Invos monitor was unable to detect variations in uteroplacental saturation during labor in healthy parturients. Keywords: near-infrared spectroscopy, uteroplacental perfusion, Invos™ monitor, tissue oxygenatio

    Coordination Modes of Americium in the Am2(C2O4)3(H2O)6·4H2O Oxalate: Synthesis, Crystal Structure, Spectroscopic Characterizations and Comparison in the M2(C2O4)3(H2O)6·nH2O (M = Ln, An) Series

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    International audienceAmericium oxalate single crystals, Am2(C2O4)3(H2O)6·4H2O, were prepared by in situ oxalic acid generation by slow hydrolysis of the diester. Their structure was determined by single-crystal X-ray diffraction and was solved by the direct methods and Fourier difference techniques. The structure (space group P21/c, a = 11.184(4) Å, b = 9.489(4) Å, c = 10.234(4) Å, ÎČ = 114.308(8)°, Z = 2) consists of layers formed by six-membered rings of actinide metals connected through oxalate ions. The americium atoms are nine-coordinated by six oxygen atoms from three bidentate oxalate ligands and three water molecules. The distances within the coordination sphere as well as infrared and Raman spectra of several isostructural lanthanide (Ce(III), Pr(III), Nd(III), Sm(III), Gd(III)) and actinide (Pu(III), Am(III)) oxalates were compared to evaluate the similarities and the differences between the two series

    Coordination Modes of Americium in the Am<sub>2</sub>(C<sub>2</sub>O<sub>4</sub>)<sub>3</sub>­(H<sub>2</sub>O)<sub>6</sub>·4H<sub>2</sub>O Oxalate: Synthesis, Crystal Structure, Spectroscopic Characterizations and Comparison in the M<sub>2</sub>(C<sub>2</sub>O<sub>4</sub>)<sub>3</sub>­(H<sub>2</sub>O)<sub>6</sub>·<i>n</i>H<sub>2</sub>O (M = Ln, An) Series

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    Americium oxalate single crystals, Am<sub>2</sub>­(C<sub>2</sub>O<sub>4</sub>)<sub>3</sub>­(H<sub>2</sub>O)<sub>6</sub>·​4H<sub>2</sub>O, were prepared by <i>in situ</i> oxalic acid generation by slow hydrolysis of the diester. Their structure was determined by single-crystal X-ray diffraction and was solved by the direct methods and Fourier difference techniques. The structure (space group <i>P</i>2<sub>1</sub>/<i>c</i>, <i>a</i> = 11.184(4) Å, <i>b</i> = 9.489(4) Å, <i>c</i> = 10.234(4) Å, ÎČ = 114.308(8)°, <i>Z</i> = 2) consists of layers formed by six-membered rings of actinide metals connected through oxalate ions. The americium atoms are nine-coordinated by six oxygen atoms from three bidentate oxalate ligands and three water molecules. The distances within the coordination sphere as well as infrared and Raman spectra of several isostructural lanthanide (Ce­(III), Pr­(III), Nd­(III), Sm­(III), Gd­(III)) and actinide (Pu­(III), Am­(III)) oxalates were compared to evaluate the similarities and the differences between the two series
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