Microcosm studies for neutralization of hypolimnic acid mine pit lake water (pH 2.6)

Ten microcosms of 0.088 m3 water volume (0.3 m i.d. and 1.20 m height) were designed for neutralization studies representing hypolimnic ecosystem models for acid mine pit lakes. Sediment and water were collected from an acid lignite mine pit lake (Brandenburg, Germany) and filled into the microcosms. To determine the efficacy of controlled in situ organic carbon amendments as a possible neutralization method, sediment and water were treated with ethanol and Carbokalk with and without wheat straw. The water chemistry was monitored for 1 yr. At start-up and end of the experiments, the sedimentwas characterized. Iron and sulfate were removed with varying intensity from the water phase as a result of microbial iron and sulfate reduction together with a subsequent precipitation of unsoluble sulfide minerals to the sediment. The pH rose, and alkalinity generation and bacterial growth were observed. Neutralization rates were calculated using equivalents of accumulated total reduced inorganic sulfur together with the nonsulfidic reactive ferrous iron in the sediment. In the treated microcosms, the neutralization rates were between 6 and 15 equiv m(-2) a(-1). Carbokalk was most effective in stimulating growth of sulfate-reducing bacteria and probably also served as inoculum. With Carbokalk together with wheat straw, the pH increased from 2.6 to around 6.5 within the whole microcosm. The critical revision of the results indicates that the application of Carbokalk (approximately 3.9 kg m(-2)) together with the application of wheat straw (approximately 9.3 kg m(-2)) is most suitable for further experiments in outdoor enclosures (mesocosms). For that case, the prediction of the water quality for a lake water column after multiple lake turnover events is presented based on batch reaction simulation using the geochemical model PHREEQC.     

The G-Protein-Coupled Estrogen Receptor (GPER/GPR30) in Ovarian Granulosa Cell Tumors

Ovarian granulosa cell tumors (GCTs) are thought to arise from cells of the ovarian follicle and comprise a rare entity of ovarian masses. We recently identified the G-protein-coupled estrogen receptor (GPER/GPR30) to be present in granulosa cells, to be regulated by gonadotropins in epithelial ovarian cancer and to be differentially expressed throughout folliculogenesis. Thus, supposing a possible role of GPER in GCTs, this study aimed to analyze GPER in GCTs. GPER immunoreactivity in GCTs (n = 26; n (primary diagnosis) = 15, n (recurrence) = 11) was studied and correlated with the main clinicopathological variables. Positive GPER staining was identified in 53.8% (14/26) of GCTs and there was no significant relation of GPER with tumor size or lymph node status. Those cases presenting with strong GPER intensity at primary diagnosis showed a significant reduced overall survival (p = 0.002). Due to the fact that GPER is regulated by estrogens, as well as gonadotropins, GPER may also be affected by endocrine therapies applied to GCT patients. Moreover, with our data supposing GPER to be associated with GCT prognosis, GPER might be considered as a possible confounder when assessing the efficacy of hormone-based therapeutic approaches in GCTs.     

Deformable Polymer Adaptive Optical Mirrors

The design, fabrication, and evaluation of deformable polymer-based micromirror devices for adaptive optic applications are described. For the mirror membranes, a freestanding polymer foil is used, which features key advantages with respect to its mechanical behavior when compared with the silicon-micromachined membranes. The fabrication technology, mirror-membrane design, packaging, and operation in a feedback-controlled closed-loop system are outlined. The feasibility for the use of the prototypes in advanced adaptive optic systems is evaluated.     

Thermal expansion in Cr:LiSrGaF6

High-temperature behaviour of LiSrGaF₆ doped with 1.5 at.% of Cr³⁺ was studied with high-resolution synchrotron angle-dispersive X-ray powder diffraction in the temperature range 298-539 K. No phase transitions were detected. The origin of negative thermal expansion along the c axis is discussed based on the temperature dependencies of structural parameters and octahedral distortions obtained with the Rietveld method. The SrF₆ slab contracts with increasing temperatures because of the diminishing F-Sr-F octahedral angles without any changes in the F-F octahedral edges not only around strontium but also around lithium and gallium. At the same time, the angular distortions of the SrF₆ octahedra are largely diminished. Such a behaviour is discussed in comparison with the thermal expansion of LiCaAlF₆ and LiSrAlF₆.     

Polymerpulvergewinnung aus Chlorierlösungen

A general process for obtaining powders of solution-chlorinated polymers with residual solvent content of less than 0.1% has been presented. The developed emulsion-precipitation process makes use of conventional technological equipment, it can be carried out in a closed circulation loop and it is free of wastes. The conditions of the technological process applied to chlorinated PVC, PE and NR differ only very little.