2,072 research outputs found
Palaeohydrology of the Mulhouse Basin: are fluid inclusions in halite tracers of past seawater composition?
Brine reactions processes were the most important factors controlling the major-ion evolution in the Oligocene, Mulhouse Basin (France) evaporite basin. The combined
analysis of fluid inclusions in primary textures in halite by Cryo-SEM-EDS with sulfate-δ34S, δ18O and 87Sr/86Sr isotope
ratios reveals hydrothermal inputs and recycling of Permian evaporites, particularly during advanced stages of evaporation in the Salt IV member which ended with sylvite formation. The lower part of the Salt IV evolved from an originally
marine input. Sulfate-δ34S shows Oligocene marine-like signatures at the base of the member (Fig.1). However, enriched sulfate-δ18O reveals the importance of re-oxidation
processes. As evaporation progressed other non-marine or marine-modified inputs from neighbouring basins became more important. This is demonstrated by an increase in K
concentrations in brine inclusions, Br in halite and variations in sulfate isotopes trends and 87Sr/86Sr ratios. The recycling of
previously precipitated evaporites was increasingly important with evaporation. Therefore, regardless of the apparent marine
sequence (gypsum, halite, potassic salts), the existence of diverse inputs and the consequent chemical changes to the brine preclude the use of trapped brine inclusions in direct reconstruction of Oligocene seawater chemistry.European Association for Geochemistry; Geochemical Societ
Effet magnéto-optique et optique des couches minces à base de ferrite de cobalt
Cette étude a pour but la mesure des effets magnéto-optiques (rotation Faraday) en fonction du champ magnétique appliqué et en fonction de la longueur d’onde, ainsi que la mesure de la transmittance (effet optique) des couches minces à base de ferrite de cobalt. Les résultats montrent une forte rotation Faraday spécifique avec des cycles d'hystérésis et des spectres de transmittance d'une bonne transparence dans la gamme Télécom (≈1550 nm).Mots-clés: ferrite de cobalt, sol-gel, couches minces, rotation Faraday, transmittance. Magneto-optical effect and optical thin films cobalt ferriteThis study was designed to measure the magneto-optical effect (Faraday rotation) according to the applied magnetic field and a function of the wavelength and the transmittance measurement (optical effect) thin film based on cobalt ferrite. The results show a high specific Faraday rotation with hysteresis cycles and transmittance spectra of a good transparency in the range Telecom (≈1550 nm).Keywords: cobalt ferrite, sol-gel thin films, Faraday rotation, transmittance
The fusion band in V1: a simple ECG guide to optimal resynchronization? An echocardiographic case report
BACKGROUND: Patients with left bundle branch block have a preserved right bundle branch conduction and the efficacy of left ventricular pacing could be explained with the fusion between artificial pulse delivered in the left lateral wall and the spontaneous right ventricular activation. Moreover, the efficacy of left ventricular pacing could be enhanced with an optimal timing between the spontaneous right ventricular activation and the left ventricular pulse. CASE PRESENTATION: We evaluated a patient (male, 47 yrs) with surgically corrected mitral regurgitation, sinus rhythm and left bundle branch block, heart failure (NYHA class III) despite medical therapy and low ejection fraction (25%): he was implanted with a biventricular device. We programmed ventricular pacing only through the left ventricular lead. We defined what we called electrocardiographic "fusion band" as follow: programming OFF the stimulator, we recorded the native electrocardiogram and measured, through the device, the intrinsic atrioventricular interval. Then, atrioventricular interval was progressively shortened by steps of 20 ms down to 100 ms. Twelve leads electrocardiogram was recorded at each step. The fusion band is the range of AV intervals at which surface electrocardiogram (mainly in V1 lead) presents an intermediate morphology between the native left bundle branch block (upper limit of the band) and the fully paced right bundle branch block (lower limit). The patient underwent echocardiographic examination at each atrioventricular interval chosen inside the fusion band. The following parameters were evaluated: ejection fraction, diastolic filling time, E wave deceleration time, aortic velocity time integral and myocardial performance index. All the echocardiographic parameters showed an improvement inside the fusion band, with a "plateau" behaviour. As the fusion band in this patient ranged from an atrioventricular delay of 200 ms to an atrioventricular delay of 120 ms, we chose an intermediate atrioventricular delay of 160 ms, presuming that this might guarantee the persistence of fusion even during any possible physiological (autonomic, effort) atrioventricular conduction variation. CONCLUSION: In this heart failure patient with left bundle branch block, tailoring of the atrioventricular interval resynchronized myocardial contraction with left ventricular pacing alone, utilizing a sensed right atrial activity and the surface electrocardiographic pattern
Etude des propriétés magnéto-optiques des couches minces à base de ferrite de cobalt obtenues par voie sol-gel
Ce travail est consacré à l'étude des propriétés magnéto-optiques (rotation Faraday) de couches minces à base de ferrite de cobalt obtenues par voie sol-gel. La contribution de la méthode sol-gel utilisée est très importante et cela permet d’obtenir des couches minces ayant une bonne qualité optique. Cette démarche nécessite juste l’utilisation de liquides magnétiques ou ferro fluides, de précurseurs de silice (pas cher) et d’un substrat de verre. Le but est d’obtenir des couches minces et étudier leurs propriétés magnéto-optiques. Les courbes obtenues à la longueur d’onde de 820 nm présentent des cycles d’hystérésis avec des rotations rémanentes de 40, 60 et 81°/cm. Ces résultats présentent une excellente rotation Faraday de 212, 318 et 340°/cm à la longueur d’onde de 820 nm. Ceci montre la forte potentialité de la matrice sol-gel dopée.Mots-clés: nanoparticules magnétiques, ferrite de cobalt, sol-gel, couches minces, rotation Faraday. Study of themagneto-optical properties of thin films cobalt ferrite obtainedby the sol-gel This work is devoted to the study of magneto-optical (Faraday rotation) of thin cobalt ferrite layers obtained by sol-gel. The contribution of the sol-gel method is very important and it allows obtaining thin film shaving a good optical quality. This requires only the use of magnetic fluids or ferro fluids, silica precursors (cheap) and a glass substrate. The goal is to obtain thin layers and study their magneto-optical properties. The curves obtained for the wave length of 820 nm have hysteresis loops with retentive rotations of 40, 60 and 81°/ cm. These results show excellentFaradayrotation 212, 318 and 340°/cm ata wave length of 820 nm. This shows the high potential of the doped sol-gel matrix.Keywords: agnetic nanoparticles, cobalt ferrite, sol-gel, thin films, Faraday rotation
Déterminisme génétique du nombre de cæca pyloriques chez la Truite fario (Salmo Trutta, Linné) et la Truite arc-en-ciel (Salmo Gairdneri, Richardson) III. — Effet du génotype et de la taille des æufs sur la réalisation du caractère chez la Truite fario
International audienceAn analysis of the variation of the number of pyloric caeca in hatchery-reared brown trout showed that :- the sex of the animals has no significant influence;- an important part of variability is caused by additive genetic factors (approximate heritability 0.4);[br/]- there is a maternal effect which inheres to the size of eggs; alevins hatched from large eggs tend to have high numbers of caeca (correlation + 0,5)- lastly, the joined action of that maternal factor and other genetic and environmental factors apparently includes interactive effects; further studies on that point would be useful.L'analyse de la variation du nombre de caeca pyloriques chez la Truite fario élevée en pisciculture a montré que :- le sexe des animaux n'a aucune influence significative;- une part importante de variabilité est d'origine génétique additive (héritabilité approximative 0,4);- il existe un effet maternel inhérent à la taille des oeufs, les alevins issus de gros aeufs tendant à avoir des nombres de caeca élevés (corrélation +0,5);- enfin, l'action conjointe de ce facteur maternel et des autres facteurs génétiques et environnementaux semble comporter des effets interactifs dont l'étude plus approfondie serait utile
Experimental observation of nonlinear Thomson scattering
A century ago, J. J. Thomson showed that the scattering of low-intensity
light by electrons was a linear process (i.e., the scattered light frequency
was identical to that of the incident light) and that light's magnetic field
played no role. Today, with the recent invention of ultra-high-peak-power
lasers it is now possible to create a sufficient photon density to study
Thomson scattering in the relativistic regime. With increasing light intensity,
electrons quiver during the scattering process with increasing velocity,
approaching the speed of light when the laser intensity approaches 10^18
W/cm^2. In this limit, the effect of light's magnetic field on electron motion
should become comparable to that of its electric field, and the electron mass
should increase because of the relativistic correction. Consequently, electrons
in such high fields are predicted to quiver nonlinearly, moving in figure-eight
patterns, rather than in straight lines, and thus to radiate photons at
harmonics of the frequency of the incident laser light, with each harmonic
having its own unique angular distribution. In this letter, we report the first
ever direct experimental confirmation of these predictions, a topic that has
previously been referred to as nonlinear Thomson scattering. Extension of these
results to coherent relativistic harmonic generation may eventually lead to
novel table-top x-ray sources.Comment: including 4 figure
Dynamic Changes in Brain Mesenchymal Perivascular Cells Associate with Multiple Sclerosis Disease Duration, Active Inflammation, and Demyelination
Vascular changes, including blood brain barrier destabilization, are common pathological features in multiple sclerosis (MS) lesions. Blood vessels within adult organs are reported to harbor mesenchymal stromal cells (MSCs) with phenotypical and functional characteristics similar to pericytes. We performed an immunohistochemical study of MSCs/pericytes in brain tissue from MS and healthy persons. Post-mortem brain tissue from patients with early progressive MS (EPMS), late stage progressive MS (LPMS), and healthy persons were analyzed for the MSC and pericyte markers CD146, platelet-derived growth factor receptor beta (PDGFRβ), CD73, CD271, alpha-smooth muscle actin, and Ki67. The MS samples included active, chronic active, chronic inactive lesions, and normal-appearing white matter. MSC and pericyte marker localization were detected in association with blood vessels, including subendothelial CD146+PDGFRβ+Ki67+ cells and CD73+CD271+PDGFRβ+Ki67– cells within the adventitia and perivascular areas. Both immunostained cell subpopulations were termed mesenchymal perivascular cells (MPCs). Quantitative analyses of immunostainings showed active lesions containing increased regions of CD146+PDGFRβ+Ki67+ and CD73+CD271+PDGFRβ+Ki67– MPC subpopulations compared to inactive lesions. Chronic lesions presented with decreased levels of CD146+PDGFRβ+Ki67+ MPC cells compared to control tissue. Furthermore, LPMS lesions displayed increased numbers of blood vessels harboring greatly enlarged CD73+CD271+ adventitial and perivascular areas compared to control and EPMS tissue. In conclusion, we demonstrate the presence of MPC subgroups in control human brain vasculature, and their phenotypic changes in MS brain, which correlated with inflammation, demyelination and MS disease duration. Our findings demonstrate that brain-derived MPCs respond to pathologic mechanisms involved in MS disease progression and suggest that vessel-targeted therapeutics may benefit patients with progressive MS
Exploring the hydrochemical evolution of brines leading to sylvite precipitation in ancient evaporite basins.
Sylvite is a very common mineral in ancient evaporite deposits. Due to the absence of current deposits, the natural geochemical mechanism/s for synsedimentary sylvite precipitation and accumulation are not well understood. Numerous sylvite deposits or portions of them have been described as a result of diagenesis (i.e. Sergipe subbasin,
Brasil). However, a number of deposits have been described as synsdimentary or being formed during primary evaporite deposition. It is the last group of deposits that can be studied to better understand the hydrochemical processes taking place in the brine at the onset of sylvite precipitation.
The Salt IV sylvite beds from the Mulhouse potash basin, Alsace (France) have been described as synsedimentary in origin (LOWENSTEIN and SPENCER, 1990; CENDON et al., 2008). While sylvite in itself does not contain fluid inclusions viable for micro analysis, primary textures in neighboring halite are used as a proxy to understand brine evolution. Two halite-sylvite cycles from the B1 and B2 layers of the potash lower seam were selected. These exhibited clear primary halite crystal textures with sylvite adapting to an irregular halite sedimentary surface and finishing with a flat surface. The nine halite samples, selected at centimeter scale, provided close to 100 single fluid inclusion analyses, representing both the transition towards sylvite precipitation and the post sylvite precipitation. The fluid inclusion analyses revealed strong fluctuations in K concentration, well over the analytical error (<10%). These variations, in the same halite crystal, seem aligned in growth bands, with fluid inclusions within a certain
growth band showing practically identical K concentrations, while neighboring bands exhibit a different concentration. Overall, the closer we are from a sylvite layer the higher K concentrations are. However, strong fluctuations continue when growth bands are compared. This pattern shows cycles of increasing K concentration along parallel
growth bands with sharp falls followed by the initiation of a new increasing trend. The small “growth band” scale of the K concentration variations, suggests very sensitive processes within the brine with potential environmental changes (i.e. seasonal variations, day-night temperature fluctuations cycles) leading towards the final mass precipitation of a sylvite layer
Regulation of pituitary MT1 melatonin receptor expression by gonadotrophin-releasing hormone (GnRH) and early growth response factor-1 (Egr-1) : in vivo and in vitro studies
Copyright: © 2014 Bae et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: This work was funded by the UK Biotechnology and Biological Sciences Research Council (BBSRC; grant BB/F020309/1; http://www.bbsrc.ac.uk/home/home.aspx). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD
Reply to the Editor-PQ-Segment Depression in Short QT Syndrome Patients: A Novel Marker for Diagnosing Short QT Syndrome?
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