Age-adapted percentiles of measured glomerular filtration in healthy individuals:extrapolation to living kidney donors over 65 years

OBJECTIVES: Most data on glomerular filtration rate (GFR) originate from subjects <65 years old, complicating decision-making in elderly living kidney donors. In this retrospective multi-center study, we calculated percentiles of measured GFR (mGFR) in donors <65 years old and extrapolated these to donors ≥65 years old. METHODS: mGFR percentiles were calculated from a development cohort of French/Belgian living kidney donors <65 years (n=1,983), using quantiles modeled as cubic splines (two linear parts joining at 40 years). Percentiles were extrapolated and validated in an internal cohort of donors ≥65 years (n=147, France) and external cohort of donors and healthy subjects ≥65 years (n=329, Germany, Sweden, Norway, France, The Netherlands) by calculating percentages within the extrapolated 5th-95th percentile (P5-P95). RESULTS: Individuals in the development cohort had a higher mGFR (99.9 ± 16.4 vs. 86.4 ± 14 and 82.7 ± 15.5 mL/min/1.73 m(2)) compared to the individuals in the validation cohorts. In the internal validation cohort, none (0%) had mGFR below the extrapolated P5, 12 (8.2%) above P95 and 135 (91.8%) between P5-P95. In the external validation cohort, five subjects had mGFR below the extrapolated P5 (1.5%), 25 above P95 (7.6%) and 299 (90.9%) between P5-P95. CONCLUSIONS: We demonstrate that extrapolation of mGFR from younger donors is possible and might aid with decision-making in elderly donors

Raman and FTIR Spectroscopy investigations of carbon-coated LixFePO4 materials

Raman and Fourier transform infrared (FTIR) spectroscopy investigations were performed on carbon-coated LiFePO4 materials differing by the temperature of their thermal treatments (575 and 800°C) and by their electrochemical performance, with that obtained at a higher temperature showing larger reversible capacity and better capacity retention at high rates. Raman spectra gave information on the carbon located at the surface of the LiFePO4 particles, which was shown for the two samples to be highly disordered with small in-plane correlation lengths (<3 nm). A UV Raman study has shown that these carbon coatings contain almost no sp3-type carbon hybridization. This study has also highlighted again that the sp3-type C/sp2-type C ratio cannot be determined straightforwardly from Raman spectra recorded with visible excitation (such as 632.8 nm), and thus that no direct correlation can be done between the Raman band intensity ratio ID/IG and the sp3-type C/sp2-type C ratio; a UV Raman study is necessary to get the true information on the sp3-type C contribution. The baseline and absolute intensity of the FTIR spectra were shown to be sensitive to changes in the electronic conductivity of the C-LiFePO4 samples. Furthermore, good crystallinity was maintained for LixFePO4 materials upon cycling, showing good reversibility of the lithium deintercalation/intercalation reaction

Reassessment of French breeding bird population sizes using citizen science and accounting for species detectability

Large-scale and long-term biodiversity monitoring can be improved by the use of Essential Biodiversity Variables, among which species population sizes provide key data for conservation programs. Relevant estimations and assessment of actual population sizes are critical for species conservation, especially in the current context of global biodiversity erosion. However, knowledge on population size varies greatly, depending on species conservation status and ranges. While the most threatened or restricted-range species generally benefit from exhaustive counts and surveys, monitoring efficiently common and widespread species tends to be neglected or is simply more challenging to achieve.In such a context, citizen science (CS) is a powerful tool for the long-term monitoring of common species through the engagement of various volunteers, permitting data acquisition on the long term and over large spatial scales. Despite this substantially increased sampling effort, detectability issues imply that even common species may remain unnoticed at suitable sites. The use of structured CS schemes, including repeated visits, enables to model the detection process, permitting reliable inferences of population size estimates.Here, we relied on a large French structured CS scheme (EPOC-ODF) comprising 27 156 complete checklists over 3 873 sites collected during the 2021-2023 breeding seasons to estimate the population size of 63 common bird species using Hierarchical Distance Sampling (HDS). These population size estimates were compared to the previous expert-based French breeding bird atlas estimations, which did not account for detectability issues.Our results indicate strong under-estimations for 65% of species in the French atlas, likely due to more conservative estimates inferred from semi-quantitative expert-based assessments. We also found a few over-estimations for species with long-range songs such as Cuculus canorus, Upupa epops or Turdus merula. Our study highlights the need to rely on sound statistical methodology to ensure unbiased ecological inferences with adequate uncertainty estimation and advocates for a higher reliance on structured CS in support of biodiversity monitoring

Structure and nonlinear optical properties of sodium–niobium phosphate glasses

International audienceThe structural description of xNb2O5–(1 − x)(NaPO3) (0 less-than-or-equals, slant x less-than-or-equals, slant 0.40) glass network is reported through high-field (18.8 T) 17O and 93Nb nuclear magnetic resonance, O1s X-ray photoelectron spectroscopy and Raman spectroscopy. The different oxygen sites (POP, PONa, NbOP and NbONb) are resolved on the spectra, their relative proportion determined and compared to indirect calculations obtained from the decomposition of 31P NMR spectra. A good agreement is obtained, thus confirming the formation of the Nb(OP)6−y(ONb)y units with increasing y leading to the clusterization of NbO6 octahedra, mainly for x > 0.2, which is related to the incomplete dissociation of Nb2O5 in the NaPO3 melt. The formation of these clusters is responsible for the large increase of the nonlinear optical properties, mainly due to the high polarizability of the Nb–O–Nb bond

Miniaturized heat flux sensor for high enthalpy plasma flow characterization

International audienceAn improved miniaturized heat flux sensor is presented aiming at measuring extreme heat fluxes of plasma wind tunnel flows. The sensor concept is based on an in-depth thermocouple measurement with a miniaturized design and an advanced calibration approach. Moreover, a better spatial estimation of the heat flux profile along the flow cross section is realized with this improved small sensor design. Based on the linearity assumption, the heat flux is determined using the impulse response of the sensor relating the heat flux to the temperature of the embedded thermocouple. The non-integer system identification (NISI) procedure is applied that allows a calculation of the impulse response from transient calibration measurements with a known heat flux of a laser source. The results show that the new sensor leads to radially highly resolved heat flux measurement for a flow with only a few centimetres in diameter, the so far not understood non-symmetric heat flux profiles do not occur with the new sensor design. It is shown that this former effect is not a physical effect of the flow, but a drawback of the classical sensor design

Second harmonic generation in poled tellurite glass

New opportunities for photonic components result from the discovering of the second harmonic generation (SHG) in thermally poled glasses in the earliest 1990s..

Second harmonic generation in poled tellurite glass

New opportunities for photonic components result from the discovering of the second harmonic generation (SHG) in thermally poled glasses in the earliest 1990s..

Second harmonic generation in poled tellurite glass

New opportunities for photonic components result from the discovering of the second harmonic generation (SHG) in thermally poled glasses in the earliest 1990s..

À la rencontre des Oiseaux (2023)

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