Endothelial cell-oligodendrocyte interactions in small vessel disease and aging

Cerebral small vessel disease (SVD) is a prevalent, neurological disease that significantly increases the risk of stroke and dementia. The main pathological changes are vascular, in the form of lipohyalinosis and arteriosclerosis, and in the white matter (WM), in the form of WM lesions. Despite this, it is unclear to what extent the key cell types involved–the endothelial cells (ECs) of the vasculature and the oligodendrocytes of the WM–interact. Here, we describe the work that has so far been carried out suggesting an interaction between ECs and oligodendrocytes in SVD. As these interactions have been studied in more detail in other disease states and in development, we explore these systems and discuss the role these mechanisms may play in SVD

Poly(vinylidene fluoride)-based macroporous separators for supercapacitors

International audienceMacroporous polymer separators based on poly(vinylidene fluoride) (PVdF) and several VdF copolymers were prepared by a phase inversion process using acetone as a solvent. The resulting macroporous separators were characterized in terms of morphology, swelling behaviour, thermal and mechanical properties and ionic conductivity. The PVdF separator had a highly porous structure (80%) and exhibited good mechanical properties. Once filled by a molar solution of tetraethylammonium tetrafluoroborate (TEABF4) in acetonitrile (AN) it provided enhanced conductivity (18 mS cm−1 at 25 °C) compared with commercial cellulose and Celgard™ separators

Assessment of ventilatory thresholds from heart rate variability in well-trained subjects during cycling.

The purpose of this study was to implement a new method for assessing the ventilatory thresholds from heart rate variability (HRV) analysis. ECG, VO2, VCO2, and VE were collected from eleven well-trained subjects during an incremental exhaustive test performed on a cycle ergometer. The "Short-Term Fourier Transform" analysis was applied to RR time series to compute the high frequency HRV energy (HF, frequency range: 0.15 - 2 Hz) and HF frequency peak (fHF) vs. power stages. For all subjects, visual examination of ventilatory equivalents, fHF, and instantaneous HF energy multiplied by fHF (HF.fHF) showed two nonlinear increases. The first nonlinear increase corresponded to the first ventilatory threshold (VT1) and was associated with the first HF threshold (T(RSA1) from fHF and HFT1 from HF.fHF detection). The second nonlinear increase represented the second ventilatory threshold (VT2) and was associated with the second HF threshold (T(RSA2) from fHF and HFT2 from HF.fHF detection). HFT1 , T(RSA1), HFT2, and T(RSA2) were, respectively, not significantly different from VT1 (VT1 = 219 +/- 45 vs. HFT1 = 220 +/- 48 W, p = 0.975; VT1 vs. T(RSA1) = 213 +/- 56 W, p = 0.662) and VT2 (VT2 = 293 +/- 45 vs. HFT2 = 294 +/- - 48 W, p = 0.956; vs. T(RSA2) = 300 +/- 58 W, p = 0.445). In addition, when expressed as a function of power, HFT1, T(RSA1), HFT2, and T(RSA2) were respectively correlated with VT1 (with HFT1 r2 = 0.94, p < 0.001; with T(RSA1) r2 = 0.48, p < 0.05) and VT2 (with HFT2 r2 = 0.97, p < 0.001; with T(RSA2 )r2 = 0.79, p < 0.001). This study confirms that ventilatory thresholds can be determined from RR time series using HRV time-frequency analysis in healthy well-trained subjects. In addition it shows that HF.fHF provides a more reliable and accurate index than fHF alone for this assessment

Assessment of ventilatory thresholds from heart rate variability in well-trained subjects during cycling.

The purpose of this study was to implement a new method for assessing the ventilatory thresholds from heart rate variability (HRV) analysis. ECG, VO2, VCO2, and VE were collected from eleven well-trained subjects during an incremental exhaustive test performed on a cycle ergometer. The "Short-Term Fourier Transform" analysis was applied to RR time series to compute the high frequency HRV energy (HF, frequency range: 0.15 - 2 Hz) and HF frequency peak (fHF) vs. power stages. For all subjects, visual examination of ventilatory equivalents, fHF, and instantaneous HF energy multiplied by fHF (HF.fHF) showed two nonlinear increases. The first nonlinear increase corresponded to the first ventilatory threshold (VT1) and was associated with the first HF threshold (T(RSA1) from fHF and HFT1 from HF.fHF detection). The second nonlinear increase represented the second ventilatory threshold (VT2) and was associated with the second HF threshold (T(RSA2) from fHF and HFT2 from HF.fHF detection). HFT1 , T(RSA1), HFT2, and T(RSA2) were, respectively, not significantly different from VT1 (VT1 = 219 +/- 45 vs. HFT1 = 220 +/- 48 W, p = 0.975; VT1 vs. T(RSA1) = 213 +/- 56 W, p = 0.662) and VT2 (VT2 = 293 +/- 45 vs. HFT2 = 294 +/- - 48 W, p = 0.956; vs. T(RSA2) = 300 +/- 58 W, p = 0.445). In addition, when expressed as a function of power, HFT1, T(RSA1), HFT2, and T(RSA2) were respectively correlated with VT1 (with HFT1 r2 = 0.94, p < 0.001; with T(RSA1) r2 = 0.48, p < 0.05) and VT2 (with HFT2 r2 = 0.97, p < 0.001; with T(RSA2 )r2 = 0.79, p < 0.001). This study confirms that ventilatory thresholds can be determined from RR time series using HRV time-frequency analysis in healthy well-trained subjects. In addition it shows that HF.fHF provides a more reliable and accurate index than fHF alone for this assessment

Crosslinking of poly(vinylene fluoride) separators by gamma-irradiation for electrochemical high power charge applications

Macroporous poly(vinylene fluoride) (PVdF) separators were prepared by phase inversion method and introduced to a gamma (γ) radiation with and without cross-linking agents. Triallyl isocyanurate (TAIC) and a macromonomer of ethylene oxide- propylene oxide (MEP) were used as a cross-linking agent. The resulting membranes were characterized in terms of thermal and mechanical properties. Ionic conductivities were determined in a molar solution of tetraethylammonium tetrafluoroborate (TEABF4) in acetonitrile (AN) and propylene carbonate (PC). Excellent mechanical properties (250 MPa at 25 °C) and conductivities (14 mS cm−1) were obtained for the cross-linked separator prepared with TAIC

Electrochemical and ab initio investigations to design a new phenothiazine based organic redox polymeric material for metal-ion battery cathodes

International audienceThanks to both electrochemical and ab initio calculation investigations, a new phenothiazine based polymeric material is proposed as a cathodic electrode for lithium batteries

Impact of fracture stratigraphy on the paleo-hydrogeology of the Madison Limestone in two basement-involved folds in the Bighorn basin, (Wyoming, USA)

International audienceBased on the study of the Madison Limestone at Sheep Mountain and Rattlesnake Mountain, a unique outcrop dataset including (1) facies and diagenetic analyses, (2) vertical persistence and cement stratigraphy of vein sets and (3) fluid inclusions thermometry are used to demonstrate the impact of folding and fracturing on paleo-hydrogeology. Quantification of the vertical persistence of fractures shows that Sheep Mountain and Rattlesnake Mountain differ by the vertical persistence of the pre-folding Laramide vein sets, which are strictly bed-confined in Sheep Mountain but cut across bedding at Rattlesnake Mountain, whereas the syn-folding veins are through-going in both. The emplacement chronology and the various sources of the fluids responsible for the paragenetic sequence are based on isotope chemistry and fluid inclusions analysis of the matrix and vein cements. At Sheep Mountain and Rattlesnake Mountain, the cements related to the burial are characterized by isotopic signatures of marine formation waters that were diluted during the karstification of the Madison Platform at the end of Mississippian. Meteoric fluids, presumably migrating during the Cenomanian from Wind River Range and Teton Range, recharge zones located in the south-west of the Bighorn Basin, were remobilized in the early bed-confined and through-going syn-folding veins of the Sheep Mountain Anticline. The former vein set drained only local fluids whose isotopic signature relates to an increase of temperature of the meteoric fluids during their migration, whereas the latter set allowed quick drainage of basinal fluids. © 2012 Elsevier B.V

Polyphased Inversions of an Intracontinental Rift: Case Study of the Marrakech High Atlas, Morocco

International audienceThe High and Middle Atlas intraplate belts in Morocco correspond to Mesozoic rifted basins inverted during the Cenozoic during Africa/Eurasia convergence. The Marrakech High Atlas lies at a key location between Atlantic and Tethyan influences during the Mesozoic rifting phase but represents today high reliefs. Age and style of deformation and the mechanisms underlying the Cenozoic inversion are nevertheless still debated. To solve this issue, we produced new low‐temperature thermochronology data (fission track and [U‐Th]/He on apatite). Two cross sections were investigated in the western and eastern Marrakech High Atlas. Results of inverse modeling allow recognizing five cooling events attributed to erosion since Early Jurassic. Apart from a first erosional event from Middle/Late Jurassic to Early Cretaceous, four stages can be related to the convergence processes between Africa and Europe since the Late Cretaceous. Our data and thermal modeling results suggest that the inversion processes are guided at first order by the fault network inherited from the rifting episodes. The sedimentary cover and the Neogene lithospheric thinning produced a significant thermal weakening that facilitated the inversion of this ancient rift. Our data show that the Marrakech High Atlas has been behaving as a giant pop‐up since the beginning of Cenozoic inversion stages

Extreme ion irradiation of oxide nanoceramics: Influence of the irradiation spectrum

Oxide nanoceramics combine the enhanced radiation tolerance of nanocrystalline materials with the chemical inertness of oxides, and are promising materials for highly corrosive and intense radiation environments. In this work, nanocrystalline Al 2 O 3 thin films are irradiated at 600 °C with either 12 MeV Au 5+ +18 MeV W 8+ or 4 MeV Ni 2+ ions. The radiation damage exposure exceeds 450 displacements per atom. A comprehensive analysis of the irradiated samples is accomplished by X-Ray Diffractometry (XRD), Transmission Electron Microscopy (TEM) and Scanning-TEM (STEM). Results are compared in an effort to establish correlations between the irradiation spectrum and the response of this class of materials to radiation environments. The results show that grain growth is the main microstructural change induced by ion irradiation in the material, regardless of the ion utilized in this work. The phase evolution may be depth-dependent, and depends strongly on the ion utilized and on the irradiation spectrum. 12 MeV Au 5+ +18 MeV W 8+ irradiations favor the formation of γ-Al 2 O 3 and α-Al 2 O 3 , while 4 MeV Ni 2+ irradiations yield mainly δ-Al 2 O 3 , accompanied by small α-Al 2 O 3 centers. Molecular dynamics simulations of displacement cascades are used to support discussions on the mass effect brought about by the different ions