First high-resolution BrO column retrievals from TROPOMI

For more than 2 decades, satellite observations from instruments such as GOME, SCIAMACHY, GOME-2, and OMI have been used for the monitoring of bromine monoxide (BrO) distributions on global and regional scales. In October 2017, the TROPOspheric Monitoring Instrument (TROPOMI) was launched on board the Copernicus Sentinel-5 Precursor platform with the goal of continuous daily global trace gas observations with unprecedented spatial resolution. In this study, sensitivity tests were performed to find an optimal wavelength range for TROPOMI BrO retrievals under various measurement conditions. From these sensitivity tests, a wavelength range for TROPOMI BrO retrievals was determined and global data for April 2018 as well as for several case studies were retrieved. Comparison with GOME-2 and OMI BrO retrievals shows good consistency and low scatter of the columns. The examples of individual TROPOMI overpasses show that due to the better signal-to-noise ratio and finer spatial resolution of 3.5×7&thinsp;km2, TROPOMI BrO retrievals provide good data quality with low fitting errors and unique information on small-scale variabilities in various BrO source regions such as Arctic sea ice, salt marshes, and volcanoes.</p

Magnetic Anisotropy and Relaxation of Pseudotetrahedral [N2O2] Bis Chelate Cobalt II Single Ion Magnets Controlled by Dihedral Twist Through Solvomorphism

The methanol solvomorph 1 amp; 8201; amp; 8901; amp; 8201;2MeOH of the cobalt II complex [Co LSal,2 amp; 8722;Ph 2] 1 with the sterically demanding Schiff base ligand 2 [1,1 amp; 8242; biphenyl] 2 ylimino methyl phenol HLSal,2 amp; 8722;Ph shows the thus far largest dihedral twist distortion between the two chelate planes compared to an ideal pseudotetrahedral arrangement. The cobalt II ion in 1 amp; 8201; amp; 8901; amp; 8201;2MeOH exhibits an easy axis anisotropy leading to a spin reversal barrier of 55.3 amp; 8197;cm amp; 8722;1, which corresponds to an increase of about 17 amp; 8201; induced by the larger dihedral twist compared to the solvent free complex 1. The magnetic relaxation for 1 amp; 8201; amp; 8901; amp; 8201;2MeOH is significantly slower compared to 1. An in depth frequency domain Fourier transform FD FT THz EPR study not only allowed the direct measurement of the magnetic transition between the two lowest Kramers doublets for the cobalt II complexes, but also revealed the presence of spin phonon coupling. Interestingly, a similar dihedral twist correlation is also observed for a second pair of cobalt II based solvomorphs, which could be benchmarked by FD FT THz EP

Comprehensive evaluation of the Copernicus Atmosphere Monitoring Service (CAMS) reanalysis against independent observations: Reactive gases

The Copernicus Atmosphere Monitoring Service (CAMS) is operationally providing forecast and reanalysis products of air quality and atmospheric composition. In this article, we present an extended evaluation of the CAMS global reanalysis data set of four reactive gases, namely, ozone (O-3), carbon monoxide (CO), nitrogen dioxide (NO2), and formaldehyde (HCHO), using multiple independent observations. Our results show that the CAMS model system mostly provides a stable and accurate representation of the global distribution of reactive gases over time. Our findings highlight the crucial impact of satellite data assimilation and emissions, investigated through comparison with a model run without assimilated data. Stratospheric and tropospheric O-3 are mostly well constrained by the data assimilation, except over Antarctica after 2012/2013 due to changes in the assimilated data. Challenges remain for O-3 in the Tropics and high-latitude regions during winter and spring. At the surface and for short-lived species (NO2), data assimilation is less effective. Total column CO in the CAMS reanalysis is well constrained by the assimilated satellite data. The control run, however, shows large overestimations of total column CO in the Southern Hemisphere and larger year-to-year variability in all regions. Concerning the long-term stability of the CAMS model, we note drifts in the time series of biases for surface O-3 and CO in the Northern midlatitudes and Tropics and for NO2 over East Asia, which point to biased emissions. Compared to the previous Monitoring Atmospheric Composition and Climate reanalysis, changes in the CAMS chemistry module and assimilation system helped to reduce biases and enhance the long-term temporal consistency of model results for the CAMS reanalysis

Investigation of meteorological conditions and BrO during ozone depletion events in Ny-Ålesund between 2010 and 2021

During polar spring, ozone depletion events (ODEs) are often observed in combination with bromine explosion events (BEEs) in Ny-Ålesund. In this study, two long-term ozone data sets (2010–2021) from ozonesonde launches and in situ ozone measurements have been evaluated between March and May of each year to study ODEs in Ny-Ålesund. Ozone concentrations below 15 ppb were marked as ODEs. We applied a composite analysis to evaluate tropospheric BrO retrieved from satellite data and the prevailing meteorological conditions during these events. During ODEs, both data sets show a blocking situation with a low-pressure anomaly over the Barents Sea and anomalously high pressure in the Icelandic Low area, leading to transport of cold polar air from the north to Ny-Ålesund with negative temperature and positive BrO anomalies found around Svalbard. In addition, a higher wind speed and a higher, less stable boundary layer are noticed, supporting the assumption that ODEs often occur in combination with polar cyclones. Applying a 20 ppb ozone threshold value to tag ODEs resulted in only a slight attenuation of the BrO and meteorological anomalies compared to the 15 ppb threshold. Monthly analysis showed that BrO and meteorological anomalies are weakening from March to May. Therefore, ODEs associated with low-pressure systems, high wind speeds, and blowing snow more likely occur in early spring, while ODEs associated with low wind speed and stable boundary layer meteorological conditions seem to occur more often in late spring. Annual evaluations showed similar weather patterns for several years, matching the overall result of the composite analysis. However, some years show different meteorological patterns deviating from the results of the mean analysis. Finally, an ODE case study from the beginning of April 2020 in Ny-Ålesund is presented, where ozone was depleted for 2 consecutive days in combination with increased BrO values. The meteorological conditions are representative of the results of the composite analysis. A low-pressure system arrived from the northeast to Svalbard, resulting in high wind speeds with blowing snow and transport of cold polar air from the north.</p

Anticancer Effects of 15d-Prostaglandin-J2 in Wild-Type and Doxorubicin-Resistant Ovarian Cancer Cells: Novel Actions on SIRT1 and HDAC

15-deoxy-delta-12,14-prostaglandin-J2 (15d-PGJ2), an arachidonic metabolite and a natural PPARγ agonist, is known to induce apoptosis in tumor cells. In this study, we investigated new therapeutic potentials of 15d-PGJ2 by determining its anticancer effects in wild-type and doxorubicin-resistant ovarian carcinoma cells. Despite high expression of resistance-inducing genes like MDR1, Bcl2 and Bcl-xl, 15d-PGJ2 strongly induced apoptosis in doxorubicin-resistant (A2780/AD) cells similar to the wild-type (A2780). This was found to be related to caspase-3/7- and NF-κB pathways but not to its PPARγ agonistic activity. 15d-PGJ2 also was able to reduce the doxorubicin resistance of A2780/AD cells at low doses as confirmed by the inhibition of gene expression of MDR1 (p-glycoprotein) and SIRT1 (a drug senescence gene). We also investigated effects of 15d-PGJ2 on cell migration and transformation using a wound-healing assay and morphological analyses, respectively. We found that 15d-PGJ2 inhibited migration most likely due to NF-κB inhibition and induced transformation of the round-shape A2780/AD cells into elongated epithelial cells due to HDAC1 inhibition. Using a 15d-PGJ2 analog, we found the mechanism of action of these new activities of 15d-PGJ2 on SIRT1 and HDAC1 gene expressions and enzyme activities. In conclusion, the present study demonstrates that 15d-PGJ2 has a high therapeutic potential to kill drug-resistant tumor cells and, the newly described inhibitory effects of this cyclo-oxygenase product on SIRT1 and HDAC will provide new opportunities for cancer therapeutics

The E-cadherin repressor Snail is associated with lower overall survival of ovarian cancer patients

Epithelial ovarian cancer is the leading cause of death among female genital malignancies. Reduced expression of the cell adhesion molecule E-cadherin was previously shown to be associated with adverse prognostic features. The role of the E-cadherin repressor Snail in ovarian cancer progression remains to be elucidated. We analysed formalin-fixed and paraffin-embedded specimens of 48 primary ovarian tumours and corresponding metastases for expression of E-cadherin and Snail by immunohistochemistry. We found a significant correlation between E-cadherin expression in primary cancers and their corresponding metastases (P<0.001). This correlation was found for Snail expression as well (P<0.001). There was a significant (P=0.008) association of reduced E-cadherin expression in primary ovarian cancer with shorter overall survival. Similarly, Snail expression in corresponding metastases (P=0.047) was associated with reduced overall survival of the patients. Additionally, the group of patients showing reduced E-cadherin and increased Snail immunoreactivity in primary tumours and corresponding metastases, respectively, had a significantly higher risk of death (P=0.002 and 0.022, respectively) when compared to the patient group with the reference expression profile E-cadherin positive and Snail negative. Taken together, the results of our study show that the E-cadherin repressor Snail is associated with lower overall survival of ovarian cancer patients

Sustained proliferation in cancer: mechanisms and novel therapeutic targets

Proliferation is an important part of cancer development and progression. This is manifest by altered expression and/or activity of cell cycle related proteins. Constitutive activation of many signal transduction pathways also stimulates cell growth. Early steps in tumor development are associated with a fibrogenic response and the development of a hypoxic environment which favors the survival and proliferation of cancer stem cells. Part of the survival strategy of cancer stem cells may manifested by alterations in cell metabolism. Once tumors appear, growth and metastasis may be supported by overproduction of appropriate hormones (in hormonally dependent cancers), by promoting angiogenesis, by undergoing epithelial to mesenchymal transition, by triggering autophagy, and by taking cues from surrounding stromal cells. A number of natural compounds (e.g., curcumin, resveratrol, indole-3-carbinol, brassinin, sulforaphane, epigallocatechin-3-gallate, genistein, ellagitannins, lycopene and quercetin) have been found to inhibit one or more pathways that contribute to proliferation (e.g., hypoxia inducible factor 1, nuclear factor kappa B, phosphoinositide 3 kinase/Akt, insulin-like growth factor receptor 1, Wnt, cell cycle associated proteins, as well as androgen and estrogen receptor signaling). These data, in combination with bioinformatics analyses, will be very important for identifying signaling pathways and molecular targets that may provide early diagnostic markers and/or critical targets for the development of new drugs or drug combinations that block tumor formation and progression

Substantial contribution of iodine to Arctic ozone destruction

Unlike bromine, the effect of iodine chemistry on the Arctic surface ozone budget is poorly constrained. We present ship-based measurements of halogen oxides in the high Arctic boundary layer from the sunlit period of March to October 2020 and show that iodine enhances springtime tropospheric ozone depletion. We find that chemical reactions between iodine and ozone are the second highest contributor to ozone loss over the study period, after ozone photolysis-initiated loss and ahead of bromine.Iodine chemistry plays a more important role than bromine chemistry in tropospheric ozone losses in the Arctic, according to ship-based observations of halogen oxides from March to October 2020.Peer reviewe