Quantifying transport into the lowermost stratosphere using simultaneous in-situ measurements of SF6 and CO2

The seasonality of transport and mixing of air into the lowermost stratosphere (LMS) is studied using distributions of mean age of air and a mass balance approach, based on in-situ observations of SF6 and CO2 during the SPURT (Spurenstofftransport in der Tropopausenregion, trace gas transport in the tropopause region) aircraft campaigns. Combining the information of the mean age of air and the water vapour distributions we demonstrate that the tropospheric air transported into the LMS above the extratropical tropopause layer (ExTL) originates predominantly from the tropical tropopause layer (TTL). The concept of our mass balance is based on simultaneous measurements of the two passive tracers and the assumption that transport into the LMS can be described by age spectra which are superposition of two different modes. Based on this concept we conclude that the stratospheric influence on LMS composition is strongest in April with extreme values of the tropospheric fractions (alpha1) below 20% and that the strongest tropospheric signatures are found in October with alpha1 greater than 80%. Beyond the fractions, our mass balance concept allows us to calculate the associated transit times for transport of tropospheric air from the tropics into the LMS. The shortest transit times (<0.3 years) are derived for the summer, continuously increasing up to 0.8 years by the end of spring. These findings suggest that strong quasi-horizontal mixing across the weak subtropical jet from summer to mid of autumn and the considerably shorter residual transport time-scales within the lower branch of the Brewer-Dobson circulation in summer than in winter dominates the tropospheric influence in the LMS until the beginning of next year's summer

Quantifying transport into the lowermost stratosphere using simultaneous in-situ measurements of SF6 and CO2

The seasonality of transport and mixing of air into the lowermost stratosphere (LMS) is studied using distributions of mean age of air and a~mass balance approach, based on in-situ observations of SF6 and CO2 during the SPURT (Spurenstofftransport in der Tropopausenregion, trace gas transport in the tropopause region) aircraft campaigns. Combining the information of the mean age of air and the water vapour distributions we demonstrate that the tropospheric air transported into the LMS above the extratropical tropopause layer (ExTL) originates predominantly from the tropical tropopause layer (TTL). The concept of our mass balance is based on simultaneous measurements of the two passive tracers and the assumption that transport into the LMS can be described by age spectra which are superposition of two different modes. Based on this concept we conclude that the stratospheric influence on LMS composition is strongest in April with tropospheric fractions (α1) below 20% and that the strongest tropospheric signatures are found in October with (α1 greater than 80%. Beyond the fractions, our mass balance concept allows to calculate the associated transit times for transport of tropospheric air from the tropics into the LMS. The shortest transit times (<0.3 years) are derived for the summer, continuously increasing up to 0.8 years by the end of spring. These findings suggest that strong quasi-horizontal mixing across the weak subtropical jet from summer to mid of autumn and the considerably shorter residual transport time-scales within the lower branch of the Brewer-Dobson circulation in summer than in winter dominates the tropospheric influence in the LMS until the beginning of next year's summer

On the structural changes in the Brewer-Dobson circulation after 2000

In this paper we present evidence that the observed increase in tropical upwelling after the year 2000 may be attributed to a change in the Brewer-Dobson circulation pattern. For this purpose, we use the concept of transit times derived from residual circulation trajectories and different in-situ measurements of ozone and nitrous dioxide. Observations from the Canadian midlatitude ozone profile record, probability density functions of in-situ N2O observations and a shift of the N2O-O3 correlation slopes, taken together, indicate that the increased upwelling in the tropics after the year 2000 appears to have triggered an intensification of tracer transport from the tropics into the extratropics in the lower stratosphere below about 500 K. This finding is corroborated by the fact that transit times along the shallow branch of the residual circulation into the LMS have decreased for the same time period (1993–2003). On a longer time scale (1979–2009), the transit time of the shallow residual circulation branch show a steady decrease of about −1 month/decade over the last 30 years, while the transit times of the deep branch remain unchanged. This highlights the fact that a change in the upwelling across the tropical tropopause is not a direct indicator for changes of the whole Brewer-Dobson circulation

On the pattern of interannual polar vortex–ozone co-variability during northern hemispheric winter

Stratospheric ozone is important for both stratospheric and surface climate. In the lower stratosphere during winter, its variability is governed primarily by transport dynamics induced by wave–mean flow interactions. In this work, we analyze interannual co-variations between the distribution of zonal-mean ozone and the strength of the polar vortex as a easure of dynamical activity during northern hemispheric winter. Specifically, we study co-variability between the seasonal means of the ozone field from modern reanalyses and polar-capaveraged temperature at 100 hPa, which represents a robust and well-defined index for polar vortex strength. We focus on the vertically resolved structure of the associated extratropical ozone anomalies relative to the winter climatology and shed light on the transport mechanisms that are responsible for this response pattern. In particular, regression analysis in pressure coordinates shows that anomalously weak polar vortex years are associated with three pronounced local ozone maxima just above the polar tropopause, in the lower to mid-stratosphere and near the stratopause. In contrast, in isentropic coordinates, using ERA-Interim reanalysis data, only the midto lower stratosphere shows increased ozone, while a small negative ozone anomaly appears in the lowermost stratosphere. These differences are related to contributions due to anomalous adiabatic vertical motion, which are implicit in potential temperature coordinates. Our analyses of the ozone budget in the extratropical middle stratosphere show that the polar ozone response maximum around 600 K and the negative anomalies around 450 K beneath both reflect the combined effects of anomalous diabatic downwelling and quasi-isentropic eddy mixing, which are associated with consecutive counteracting anomalous ozone tendencies on daily timescales. We find that approx. 71 % of the total variability in polar column ozone in the stratosphere is associated with year-by-year variations in polar vortex strength based on ERA5 reanalyses for the winter seasons 1980–2022. MLS observations for 2005–2020 show hat around 86 % can be explained by these co-variations with the polar vortex

On the magnitude and sensitivity of the quasi-biennial oscillation response to a tropical volcanic eruption

Volcanic eruptions that inject sulfur dioxide into the stratosphere have the potential to alter large-scale circulation patterns, such as the quasi-biennial oscillation (QBO), which can affect weather and transport of chemical species. Here, we conduct simulations of tropical volcanic eruptions using the UM-UKCA aerosol-climate model with an explicit representation of the QBO. Eruptions emitting 60 Tg of SO2 (i.e. the magnitude of the 1815 Mt. Tambora eruption) and 15 Tg of SO2 (i.e. the magnitude of the 1991 Mt. Pinatubo eruption) were initiated at the Equator during two different QBO states. We show that tropical eruptions delay the progression of the QBO phases, with the magnitude of the delay dependent on the initial wind shear in the lower stratosphere and a much longer delay when the shear is easterly than when it is westerly. The QBO response in our model is driven by vertical advection of momentum by the stronger tropical upwelling caused by heating due to the increased volcanic sulfate aerosol loading. Direct aerosol-induced warming with subsequent thermal wind adjustment, as proposed by previous studies, is found to only play a secondary role. This interpretation of the response is supported by comparison with a simple dynamical model. The dependence of the magnitude of the response on the initial QBO state results from differences in the QBO secondary circulation. In the easterly shear zone of the QBO, the vertical component of the secondary circulation is upward and reinforces the anomalous upwelling driven by volcanic aerosol heating, whereas in the westerly shear zone the vertical component is downward and opposes the aerosol-induced upwelling. We also find a change in the latitudinal structure of the QBO, with the westerly phase of the QBO strengthening in the hemisphere with the lowest sulfate aerosol burden. Overall, our study suggests that tropical eruptions of Pinatubo magnitude or larger could force changes to the progression of the QBO, with particularly disruptive outcomes for the QBO if the eruption occurs during the easterly QBO shear

Enhanced expression of the stemness-related factors OCT4, SOX15 and TWIST1 in ectopic endometrium of endometriosis patients

Abstract Background Current evidence suggests that endometrial-derived stem cells, spilled in the peritoneal cavity via retrograde menstruation, are key players in the establishment of endometriotic lesions. The aim of this study was to determine the presence and distribution of the stemness-related factors OCT4, SOX15, TWIST1 and DCAMLK1 in women with and without endometriosis. Methods Immunohistochemical analysis was used to determine stromal and epithelial expression of OCT4, SOX15, TWIST1 and DCAMLK1 in endometriosis patient (EP) endometrium (n = 69) and endometriotic tissue (n = 90) and in control endometrium (n = 50). Quantitative Real-Time PCR of OCT4, SOX15 TWIST1 and DCAMLK1 was performed in paired samples of EP endometrium and endometriotic tissue. Co-immunofluorescence staining was performed for OCT4 and SOX15. For statistical analyses we used unpaired t-test, Fisher combination test and Spearman test. For paired analyses, paired t-test and McNemar test were used. Results We detected a significant correlation between the expression of the established stem cell marker OCT4 and the stemness-related markers SOX15 (p < 0.001) and TWIST1 (p = 0.002) but not DCAMLK1. We showed a colocalization of SOX15 and OCT4 in epithelial and stromal cells of endometriotic tissue by coimmunofluorescence. A concordant expression of OCT4 and SOX15 in the same sample was observed in epithelial cells of the endometriotic tissue (71.7%). The expression of stemness-related factors was not associated with proliferative or secretory phase of the menstrual cycle in endometriosis patients but was found to be differentially expressed during the menstrual cycle in the control group. Increased expression of epithelial OCT4, SOX15 and TWIST1 was detected in endometriotic tissue compared to EP endometrium in paired (p = 0.021, p < 0.001 and p < 0.001) and unpaired analysis (p = 0.040, p < 0.001 and p = 0.001). Conclusion Our findings support the hypothesis that upregulation of stem cell-related factors contribute to the establishment of endometriotic lesions. Trial registration The study was approved by the institutional review board (545/2010 on 6th of May 2014) of the Medical University of Vienna ( http://ethikkommission.meduniwien.ac.at/fileadmin/ethik/media/dokumente/register/alle_2010.pdf )

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<p>Box plot analysis of serum concentrations of sRAGE (A), esRAGE (B), S100A9 (C) and HMGB1 (D) in patients with CTEPH (n = 26) and controls (n = 33). Independent Student’s t-test was used to compare groups. <i>RAGE</i> receptor for advanced glycation endproducts, <i>sRAGE</i> soluble RAGE, <i>esRAGE</i> endogenous secretory RAGE, <i>S100A9</i> member of S100 family of Ca+ binding proteins, <i>HMGB1</i> high mobility group box1, <i>CTEPH</i> chronic thromboembolic pulmonary hypertension.</p

Eplerenone prevents salt-induced vascular stiffness in Zucker diabetic fatty rats: a preliminary report

Background Aldosterone levels are elevated in a rat model of type 2 diabetes mellitus, the Zucker Diabetic fatty rat (ZDF). Moreover blood pressure in ZDF rats is salt-sensitive. The aim of this study was to examine the effect of the aldosterone antagonist eplerenone on structural and mechanical properties of resistance arteries of ZDF-rats on normal and high-salt diet. Methods After the development of diabetes, ZDF animals were fed either a normal salt diet (0.28%) or a high-salt diet (5.5%) starting at an age of 15 weeks. ZDF rats on high-salt diet were randomly assigned to eplerenone (100 mg/kg per day, in food) (ZDF+S+E), hydralazine (25 mg/kg per day) (ZDF+S+H), or no treatment (ZDF+S). Rats on normal salt-diet were assigned to eplerenone (ZDF+E) or no treatment (ZDF). Normoglycemic Zucker lean rats were also divided into two groups receiving normal (ZL) or high-salt diet (ZL+S) serving as controls. Systolic blood pressure was measured by tail cuff method. The experiment was terminated at an age of 25 weeks. Mesenteric resistance arteries were studied on a pressurized myograph. Specifically, vascular hypertrophy (media-to-lumen ratio) and vascular stiffness (strain and stress) were analyzed. After pressurized fixation histological analysis of collagen and elastin content was performed. Results Blood pressure was significantly higher in salt-loaded ZDF compared to ZDF. Eplerenone and hydralazine prevented this rise similarily, however, significance niveau was missed. Media-to-lumen ratio of mesenteric resistance arteries was significantly increased in ZDF+S when compared to ZDF and ZL. Both, eplerenone and hydralazine prevented salt-induced vascular hypertrophy. The strain curve of arteries of salt-loaded ZDF rats was significantly lower when compared to ZL and when compared to ZDF+S+E, but was not different compared to ZDF+S+H. Eplerenone, but not hydralazine shifted the strain-stress curve to the right indicating a vascular wall composition with less resistant components. This indicates increased vascular stiffness in salt-loaded ZDF rats, which could be prevented by eplerenone but not by hydralazine. Collagen content was increased in ZL and ZDF rats on high-salt diet. Eplerenone and hydralazine prevented the increase of collagen content. There was no difference in elastin content. Conclusion Eplerenone and hydralazine prevented increased media-to-lumen ratio in salt-loaded ZDF-rats, indicating a regression of vascular hypertrophy, which is likely mediated by the blood pressure lowering-effect. Eplerenone has additionally the potential to prevent increased vascular stiffness in salt-loaded ZDF-rats. This suggests an effect of the specific aldosterone antagonist on adverse vascular wall remodelling