Publications by authors named "P Louvat"

Article Synopsis
  • This study is the first to report selenium (Se) isotopes in marine top predators, specifically focusing on giant petrels, and provides extensive characterization of Se isotopes in animals.
  • A new methodology was developed using hydride generation and mass spectrometry to analyze various internal organs of the seabirds, revealing different Se isotopic signatures among tissues.
  • The findings show that the liver has higher concentrations of heavier Se isotopes and indicate a strong correlation between the presence of selenoneine and shifts in Se isotopic composition, suggesting a promising avenue for further understanding Se dynamics in animals.
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This paper introduces an enhanced technique for analyzing iron isotopes in complex marine and biological samples. A dedicated iron purification method for biological marine matrices, utilizing three ion exchange columns, is validated. The MC-ICPMS in pseudo-high-resolution mode determines precise iron isotopic ratios, with sensitivity improved through the DSN-100 desolvating nebulizer system and Apex-IR.

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Infiltration of effluents from wastewater treatment plants (WWTP) into groundwater can be a source of Contaminants of Emerging Concern (CECs), such as pharmaceutical compounds, that are not fully removed during the treatment processes. A multi-tracer approach, based on hydrogeochemical, isotopic, and organic tracers, is applied in the Vistrenque Aquifer (Gard, France) to assess the dispersion of such unintentional plumes and its potential implication on groundwater quality for CECs in a small catchment area. In this area, a point source of WWTP effluent causes contaminant infiltration and unintentional transfer to the aquifer.

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Iron is geologically important and biochemically crucial for all microorganisms, plants and animals due to its redox exchange, the involvement in electron transport and metabolic processes. Despite the abundance of iron in the earth crust, its bioavailability is very limited in nature due to its occurrence as ferrihydrite, goethite, and hematite where they are thermodynamically stable with low dissolution kinetics in neutral or alkaline environments. Organisms such as bacteria, fungi, and plants have evolved iron acquisition mechanisms to increase its bioavailability in such environments, thereby, contributing largely to the iron cycle in the environment.

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Chronic kidney disease induces disruption of the intestinal epithelial barrier, leading to gut bacterial translocation. Here, we appreciated bacterial translocation by analyzing circulating lipopolysaccharides (LPS) using two methods, one measuring only active free LPS, and the other quantifying total LPS as well as LPS lipid A carbon chain length. This was done in end-stage renal disease (ESRD) patients and healthy volunteers (HV).

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