Different methods for administering 17β-estradiol to ovariectomized rats result in opposite effects on ischemic brain damage

Background  

Numerous stroke studies have controversially shown estrogens to be either neuroprotective or neurodamaging. The discordant results observed in rat brain ischemia models may be a consequence of discrepancies in estrogen administration modes resulting in plasma concentration profiles far from those intended. To test this hypothesis we reproduced in detail and extended an earlier study from our lab using a different mode of 17β-estradiol administration; home-made silastic capsules instead of commercial slow-release 17β-estradiol pellets. Four groups of female rats (n = 12) were ovariectomized and administered 17β-estradiol or placebo via silastic capsules. All animals underwent MCAo fourteen days after ovariectomy and were sacrificed three days later.     

Poincaré duality for p-adic Lie groups

We establish Poincaré duality for continuous group cohomology of p-adic Lie groups with rational coefficients and compare integral structures under this duality.     

High pressure-induced structural effects in plastic packaging

Today, flexible vacuum packages are predominantly used for products to be subjected to high pressure treatment. However, tray packages with a modified atmosphere are in demand, which provide a high failure rate with respect to gas and water vapour permeability and packaging integrity. Methods to follow permeation processes under high pressure were developed and used together with optical microscopy, confocal scanning laser microscopy, Raman spectroscopy and atomic force microscopy to identify the mechanisms for changes in permeability and damage to the packaging materials. Single film samples and pouch packages filled with model products were studied. Results indicate a reversible decrease in the coefficients of diffusion and permeation under the impact of high pressure, due to the compression of the polymeric bulk. Irreversible changes in the polymeric materials are associated with gases in the packaging head space, which cause high local temperatures and create damage due to rapid deliberation upon the pressure drop at the end of the high pressure cycle.     

On the Weak Order of Orthogonal Groups

A complete lattice structure is defined on the underlying set of the orthogonal group of a real Euclidean space, by a construction analogous to that of the weak order of Coxeter systems in terms of root systems. This produces a complete rootoid in the sense of Dyer, with the orthogonal group as underlying group. It is shown that this complete lattice has a saturation property which is used along with other properties of the lattice to characterize the maximal totally ordered subsets of the lattice as collections of initial sections with respect to a total ordering on the positive roots.     

The low temperature magnetic phase diagram of EuxSr1−xTiO3

Specific heat and magnetization measurements demonstrate that the antiferromagnetic (AFM) phase transition at T _N  = 5.7 K of EuTiO₃ is rapidly suppressed with Sr doping in Eu _x Sr_1?x TiO₃. Close to x = 0.25, T _N  = 0 K and AFM order vanishes. Above this critical concentration a finite transition temperature to an AFM phase is observed. The exchange couplings are derived as a function of x and the corresponding low temperature phase diagram is presented.     

Convex Geometries on Root Systems

This article investigates several convex closure operators on a finite root system. It is shown that a natural closure operator on the positive root system of a finite Weyl group satisfies the anti-exchange condition for all root systems except type F ₄.     

Atomic‐Scale Observation of the Metal–Promoter Interaction in Rh‐Based Syngas‐Upgrading Catalysts

The direct conversion of syngas to ethanol, typically using promoted Rh catalysts, is a cornerstone reaction in CO₂ utilization and hydrogen storage technologies. A rational catalyst development requires a detailed structural understanding of the activated catalyst and the role of promoters in driving chemoselectivity. Herein, we report a comprehensive atomic‐scale study of metal–promoter interactions in silica‐supported Rh, Rh–Mn, and Rh–Mn–Fe catalysts by aberration‐corrected (AC) TEM. While the catalytic reaction leads to the formation of a Rh carbide phase in the Rh–Mn/SiO₂ catalyst, the addition of Fe results in the formation of bimetallic Rh–Fe alloys, which further improves the selectivity and prevents the carbide formation. In all promoted catalysts, Mn is present as an oxide decorating the metal particles. Based on the atomic insight obtained, structural and electronic modifications induced by promoters are revealed and a basis for refined theoretical models is provided.     

Sensitive detection of hydroxymethylcytosine levels in normal and neoplastic cells and tissues

A new sensitive analytical method using capillary electrophoresis with laser induced fluorescence (CE‐LIF) was applied for the simultaneous detection of DNA methylation and hydroxymethylation levels in human cancers of different origin. DNA hydroxymethylation, measured as 5‐hydroxymethylcytosine (5hmC) levels, was decreased in gliomas with mutation in the isocitrate dehydrogenase 1 (IDH1) gene when compared to IDH1‐wildtype gliomas. Independent from IDH1 mutation, 5hmC levels were decreased in lung carcinomas when compared to normal lung tissue. Reduced DNA hydroxymethylation was also observed upon dedifferentiation in cultured murine embryonic fibroblasts. Our data show that reduced DNA hydroxymethylation is related to cellular dedifferentiation and can be detected in various types of cancers, independent from the IDH1 mutation status. Quantitative determination of altered 5hmC levels may therefore have potential as a biomarker linked to cellular differentiation and tumorigenesis.