1,064 research outputs found
Micronecton analysis from the insular shelf of the Kerguelen Islands: the amphipod <i>Themisto gaudichaudii</i>âs case
Future Practices and Technologies in Anthropometrics and Body Scanning
There have also been great strides in software development, to convert and manipulate 3D scan data, to make mannequins, lasts, patterns, tooling files, etc. The presenters invited to this special topic session are at the forefront of these research spaces, either through evaluating or utilizing these technologies for product design and developmen
Regional hydrological impacts of climatic change : hydroclimatic variability : proceedings of symposium S6 held during the seventh IAHS scientific assembly
Fast Measurements of the Electron Beam Transverse Size and Position on SOLEIL Storage Ring
On SOLEIL storage ring, three beamlines are dedicated to electron beam diagnostics: two in the X-ray range and one in the visible range. The visible range beamline uses the synchrotron radiation which is emitted in one of the ring dipoles and further extracted by a slotted mirror operated in surf-mode (surfing on the upper part of the synchrotron layer). The radiation in the visible range is then transported towards a diagnostic hutch in the experimental hall, allowing electron beam imaging at the source point onto a standard CCD camera. In the perspective of prototyping works for the eventually forthcoming upgrade of SOLEIL, and for the on-going commissioning of a new Multipole Injection Kicker (MIK), we recently installed in this hutch two new branches ended by two new cameras (a KALYPSO system and a standard CMOS camera). We report in this paper the optimization we performed on the mirror mode of operation, as well as on spectral filtering, polarization selection, image plane location, fast acquisition tools, to improve the resolution and increase the speed of our initial transverse beam size measurement at source point
The endothelial mineralocorticoid receptor regulates vasoconstrictor tone and blood pressure
Pathophysiological aldosterone (aldo)/mineralocorticoid receptor (MR) signaling has significant effects on the cardiovascular system, resulting in hypertension and cardiovascular remodeling; however, the specific contribution of the vascular MR to blood pressure regulation remains to be established. To address this question, we generated a mouse model with conditional overexpression of the MR in endothelial cells (MR-EC). In basal conditions, MR-EC mice developed moderate hypertension that could be reversed by canrenoate, a pharmacological MR antagonist. MR-EC mice presented increased contractile response of resistance arteries to vasoconstrictors (phenylephrine, thromboxane A(2) analog, angiotensin II, and endothelin 1) in the absence of vascular morphological alterations. The acute blood pressure response to angiotensin II or endothelin 1 infusion was increased in MR-EC mice compared with that in littermate controls. These observations demonstrate that enhanced MR activation in the endothelium generates an increase in blood pressure, independent of stimulation of renal tubular Na(+) transport by aldo/MR or direct activation of smooth muscle MR and establish one mechanism by which endothelial MR activation per se may contribute to impaired vascular reactivity
Turbo-égalisation des modulations MAQ-M sur canaux non stationnaires sélectifs en fréquences
- Dans cet article nous présentons un nouveau récepteur appelé turbo-égaliseur pour les modulations de type MAQ-M transmises sur des canaux sélectifs en fréquences non stationnaires. Ce récepteur utilise un traitement conjoint de l'égalisation adaptative et du codage de canal au travers d'un processus itératif. En utilisant un principe similaire au turbo-codes, on parvient pour certaines transmissions à supprimer totalement les dégradations dues à l'interférence entre symboles. Des résultats sont présentés pour les modulations MAQ-4 et MAQ-16
Inâsitu Bragg coherent Xâray diffraction during tensile testing of an individual Au nanowire
Nanomechanical testing methods have drawn significant attention in both scientific and industrial research fields owing to unique deformation mechanisms in constrained volumes that underpin new property regimes. In-situ imaging equipment is now routinely employed to monitor the live evolution of material response during mechanical loading, with many of the testing developments tailored for electron microscopes (EMs). More recently, progress towards quantitative in-situ testing at synchrotron beamlines1â3 enabled by innovations in source brightness, focusing optics, and large size detectors has been made. Novel techniques such as Bragg coherent X-ray diffraction promise 3D information with phase information related to displacement fields (elastic strain, defects) within the material. However, despite the rich information that can be collected, many challenges arise in the realization of in-situ imaging of single nanostructures using such methods, including meticulous sample preparation and complex data analysis in retrieving phase information.
In this work, we present the first successful systematic single nanowire tensile test while simultaneously recording 3D Bragg peaks using coherent X-rays. Defect free single crystalline \u3c110\u3e oriented Au nanowires were grown by physical vapor deposition4 and a 100 nm nanowire was harvested from the substrate and transferred to a nanotensile stage within a microelectromechanical system chip, which can be mounted to a coherent X-ray beamline. 3D Bragg peaks were recorded with nanofocused beam combined with 2D detector at each displacement step to discuss the evolution of strain and rotation of the nanowire during the tensile test. The movement of the peak sensitively depicted evolution of the deformation of the nanowire. In addition, the 3D Bragg coherent X-ray diffraction followed by phase retrieval has shown to reveal the internal strain state of nanostructure5 and this advanced technique is expected to reveal unique surface effects that mediate the overall mechanical performance of nano-scaled materials.
1. Cornelius, T. W. et al. In situ three-dimensional reciprocal-space mapping during mechanical deformation. J. Synchrotron Radiat. 19, 688â694 (2012).
2. Ren, Z. et al. Scanning force microscope for in situ nanofocused X-ray diffraction studies. J. Synchrotron Radiat. 21, 1128â1133 (2014).
3. Leclere, C. et al. In situ bending of an Au nanowire monitored by micro Laue diffraction. J. Appl. Crystallogr. 48, 291â296 (2015).
4. Richter, G. et al. Ultrahigh strength single crystalline nanowhiskers grown by physical vapor deposition. Nano Lett. 9, 3048â3052 (2009).
5. Haag, S. et al. Anomalous coherent diffraction of core-shell nano-objects: A methodology for determination of composition and strain fields. Phys. Rev. B 87, 35408 (2013)
Stability and Electronic Properties of TiO2 Nanostructures With and Without B and N Doping
We address one of the main challenges to TiO2-photocatalysis, namely band gap
narrowing, by combining nanostructural changes with doping. With this aim we
compare TiO2's electronic properties for small 0D clusters, 1D nanorods and
nanotubes, 2D layers, and 3D surface and bulk phases using different
approximations within density functional theory and GW calculations. In
particular, we propose very small (R < 0.5 nm) but surprisingly stable
nanotubes with promising properties. The nanotubes are initially formed from
TiO2 layers with the PtO2 structure, with the smallest (2,2) nanotube relaxing
to a rutile nanorod structure. We find that quantum confinement effects - as
expected - generally lead to a widening of the energy gap. However,
substitutional doping with boron or nitrogen is found to give rise to
(meta-)stable structures and the introduction of dopant and mid-gap states
which effectively reduce the band gap. Boron is seen to always give rise to
n-type doping while depending on the local bonding geometry, nitrogen may give
rise to n-type or p-type doping. For under coordinated TiO2 surface structures
found in clusters, nanorods, nanotubes, layers and surfaces nitrogen gives rise
to acceptor states while for larger clusters and bulk structures donor states
are introduced
A short leucocyte telomere length is associated with development of insulin resistance
International audienceAIMS/HYPOTHESIS:A number of studies have shown that leucocyte telomere length (LTL) is inversely associated with insulin resistance and type 2 diabetes mellitus. The aim of the present longitudinal cohort study, utilising a twin design, was to assess whether shorter LTL predicts insulin resistance or is a consequence thereof.METHODS:Participants were recruited between 1997 and 2000 through the population-based national Danish Twin Registry to participate in the GEMINAKAR study, a longitudinal evaluation of metabolic disorders and cardiovascular risk factors. Baseline and follow-up measurements of LTL and insulin resistance over an average of 12 years were performed in a subset of the Registry consisting of 338 (184 monozygotic and 154 dizygotic) same-sex twin pairs.RESULTS:Age at baseline examination was 37.4â±â9.6 (meanâ±âSD) years. Baseline insulin resistance was not associated with age-dependent changes in LTL (attrition) over the follow-up period, whereas baseline LTL was associated with changes in insulin resistance during this period. The shorter the LTL at baseline, the more pronounced was the increase in insulin resistance over the follow-up period (pâ<â0.001); this effect was additive to that of BMI. The co-twin with the shorter baseline LTL displayed higher insulin resistance at follow-up than the co-twin with the longer LTL.CONCLUSIONS/INTERPRETATION:These findings suggest that individuals with short LTL are more likely to develop insulin resistance later in life. By contrast, presence of insulin resistance does not accelerate LTL attrition
- âŠ