Wie vollständig ist der biologische Abbau: Ermittlung und Analytik refraktärer Verbindungen am Beispiel von linearem Alkylbenzolsulfonat (LAS)

Linear alkylbenzenesulfonate (LAS) is the worldwide most used synthetic surfactant. Its elimination in activated sludge goes nearly to completion. But in laboratory test systems a well primary but no total biodegradation, measured by removal of dissolved organic carbon (DOC), has been found till now. On a new test system to detect refractory organic carbon (ROC) a commercial LAS yields > 5% of ROC. With HPLC and GC/MS analysis the refractory organic compounds are determined as different isomers of sulfophenylcarboxylates and carboxylated dialkyltetralinesulfonates. Dialkyltetralinesulfonates are beside branched alkylbenzenesulfonates known impurities in commercial LAS. These impurities undergo a complete primary biodegradation in the used test system. It is estimated, that the detected refractory sulfophenylcarboxylates derived from branched alkylbenzenesulfonates and not from LAS. The test to detect ROC effects on the base of a trickling filter, where the test substance is dissolved in a mineral salt solution and trickles over activated sludge, which is fixed on a support. Eluate derived from the trickling filter is readded with new test substrate and fed again to the filter. Readdition is repeated till the content of nondegraded parts in the eluate is high enough. Then the eluate is fed to the filter without substrate readdition as long as the remaining organic carbon in the eluate is constant. The residual DOC is called refractory

Determinanten der Überlebenschancen neugegründeter Kleinbetriebe

"Mit Blick auf ihr Potential zur Schaffung neuer Arbeitsplätze gelten neugegründete Kleinbetriebe vielfach als Hoffnungsträger der Beschäftigungspolitik. Grund zur Hoffnung kann es allerdings nur für diejenigen Betriebe geben, die tatsächlich über einen längeren Zeitraum hinweg bestehen können. Auf der Basis einer empirischen Studie, in der Anfang 1990 rund 1.850 Unternehmensgründer der Jahre 1985/86 in München und Oberbayern interviewt wurden, untersucht der Beitrag Determinanten der Überlebenschancen neugegründeter Kleinbetriebe. Theoretische Perspektiven für die Auswahl möglicher Bestimmungsfaktoren der Überlebenschancen sind zum einen die Humankapitaltheorie und zum anderen der organisationsökologische Ansatz. Für die statistische Auswertung des Datenmaterials werden Methoden der Ereignisdatenanalyse verwendet. Wichtige Ergebnisse sind: Die Humankapitalressourcen des Unternehmensgründers (allgemeines Humankapital in Form von Bildung und Berufserfahrung sowie spezifisches Humankapital in Form von vorheriger Branchenerfahrung) und die Anfangsgröße eines Betriebes (Startkapital, Zahl der Beschäftigten zum Zeitpunkt der Gründung) sind die bedeutsamsten Einflußfaktoren der Überlebenschancen einer Neugründung. Für zahlreiche andere Faktoren (z.B. Geschlecht und Nationalität des Gründers, Einzel- versus Partnergründung, Standort) ergeben sich in der multivariaten Analyse keine signifikanten Effekte. Das Risiko einer Betriebsauflösung steigt im ersten Jahr an, erreicht nach neun bis zwölf Monaten ein Maximum und sinkt dann kontinuierlich ab." (Autorenreferat)Kleinbetrieb, Unternehmensgründung, Zukunftsperspektive - Determinanten, München, Bayern, Bundesrepublik Deutschland

The SNARE Machinery in Mast Cell Secretion

Mast cells are known as inflammatory cells which exert their functions in allergic and anaphylactic reactions by secretion of numerous inflammatory mediators. During an allergic response, the high-affinity IgE receptor, FcεRI, becomes cross-linked by receptor-bound IgE and antigen resulting in immediate release of pre-synthesized mediators – stored in granules – as well as in de novo synthesis of various mediators like cytokines and chemokines. Soluble N-ethylmaleimide-sensitive factor attachment protein (SNAP) receptors (SNARE) proteins were found to play a central role in regulating membrane fusion events during exocytosis. In addition, several accessory regulators like Munc13, Munc18, Rab GTPases, secretory carrier membrane proteins, complexins, or synaptotagmins were found to be involved in membrane fusion. In this review we summarize our current knowledge about the SNARE machinery and its mechanism of action in mast cell secretion

Green Jobs and Climate Change: The Saxony Anhalt Region - Renewable Energies in the Perspective of the Economy and Vocational Education and Training

A study based on the final report of the international Workshop “Green Jobs and Climate Change”, Magdeburg, Saxony-Anhalt, Germany, from December 10 to December 13, 2012, on behalf of the Gesellschaft für  Internationale Zusammenarbeit (GIZ) and the German Federal Ministry of Economic Cooperation and Development (BMZ

Lobar Dementia due to Extreme Widening of Virchow-Robin Spaces in One Hemisphere

Widened perivascular spaces known as Virchow-Robin spaces (VRS) are often seen on MRI and are usually incidental findings. It is unclear if enlarged VRS can be associated with neurological deficits. In this report, we describe a case of lobar dementia associated with unusual VRS widening in one cerebral hemisphere. A 77-year-old woman, seen at a memory clinic, presented with progressive cognitive decline, left hemianopsia, and mild pyramidal signs on the left side. On MRI, unusually wide VRS were visible, predominantly in the right centrum semiovale and the right temporo-occipital white matter. The clinical syndrome was consistent with the extent and location of the abnormally dilated VRS. The high MR signal in white matter bridges between the VRS suggested parenchymal damage, possibly representing gliotic white matter. No evidence for another etiology was found on cerebral MRI and rCBF SPECT. As a conclusion, enlarged VRS in one cerebral hemisphere may be associated with cognitive change and neurological deficits

Isotope‐labeled amyloid‐β does not transmit to the brain in a prion‐like manner after peripheral administration

Findings of early cerebral amyloid-β deposition in mice after peripheral injection of amyloid-β-containing brain extracts, and in humans following cadaveric human growth hormone treatment raised concerns that amyloid-β aggregates and possibly Alzheimer’s disease may be transmissible between individuals. Yet, proof that Aβ actually reaches the brain from the peripheral injection site is lacking. Here, we use a proteomic approach combining stable isotope labeling of mammals and targeted mass spectrometry. Specifically, we generate 13C-isotope-labeled brain extracts from mice expressing human amyloid-β and track 13C-lysine-labeled amyloid-β after intraperitoneal administration into young amyloid precursor protein-transgenic mice. We detect injected amyloid-β in the liver and lymphoid tissues for up to 100 days. In contrast, injected 13C-lysine-labeled amyloid-β is not detectable in the brain whereas the mice incorporate 13C-lysine from the donor brain extracts into endogenous amyloid-β. Using a highly sensitive and specific proteomic approach, we demonstrate that amyloid-β does not reach the brain from the periphery. Our study argues against potential transmissibility of Alzheimer’s disease while opening new avenues to uncover mechanisms of pathophysiological protein deposition.Peer reviewe

Chasing Brane Inflation in String-Theory

We investigate the embedding of brane anti-brane inflation into a concrete type IIB string theory compactification with all moduli fixed. Specifically, we are considering a D3-brane, whose position represents the inflaton $\phi$, in a warped conifold throat in the presence of supersymmetrically embedded D7-branes and an anti D3-brane localized at the tip of the warped conifold cone. After presenting the moduli stabilization analysis for a general D7-brane embedding, we concentrate on two explicit models, the Ouyang and the Kuperstein embeddings. We analyze whether the forces, induced by moduli stabilization and acting on the D3-brane, might cancel by fine-tuning such as to leave us with the original Coulomb attraction of the anti D3-brane as the driving force for inflation. For a large class of D7-brane embeddings we obtain a negative result. Cancelations are possible only for very small intervals of $\phi$ around an inflection point but not globally. For the most part of its motion the inflaton then feels a steep, non slow-roll potential. We study the inflationary dynamics induced by this potential.Comment: 34 pages, 4 figures. Final version published in JCA

Cross-Sectional Comparison of Small Animal [F-18]-Florbetaben Amyloid-PET between Transgenic AD Mouse Models

We aimed to compare [F-18]-florbetaben PET imaging in four transgenic mouse strains modelling Alzheimer's disease (AD), with the main focus on APPswe/PS2 mice and C57Bl/6 mice serving as controls (WT). A consistent PET protocol (N = 82 PET scans) was used, with cortical standardized uptake value ratio (SUVR) relative to cerebellum as the endpoint. We correlated methoxy-X04 staining of beta-amyloid with PET results, and undertook ex vivo autoradiography for further validation of a partial volume effect correction (PVEC) of PET data. The SUVR in APPswe/PS2 increased from 0.95 +/- 0.04 at five months (N = 5) and 1.04 +/- 0.03 (p < 0.05) at eight months (N = 7) to 1.07 +/- 0.04 (p < 0.005) at ten months (N = 6), 1.28 +/- 0.06 (p < 0.001) at 16 months (N = 6) and 1.39 +/- 0.09 (p < 0.001) at 19 months (N = 6). SUVR was 0.95 +/- 0.03 in WT mice of all ages (N = 22). In APPswe/PS1G384A mice, the SUVR was 0.93/0.98 at five months (N = 2) and 1.11 at 16 months (N = 1). In APPswe/PS1dE9 mice, the SUVR declined from 0.96/0.96 at 12 months (N = 2) to 0.91/0.92 at 24 months (N = 2), due to beta-amyloid plaques in cerebellum. PVEC reduced the discrepancy between SUVR-PET and autoradiography from -22% to +2% and increased the differences between young and aged transgenic animals. SUVR and plaque load correlated highly between strains for uncorrected (R = 0.94, p < 0.001) and PVE-corrected (R = 0.95, p < 0.001) data. We find that APPswe/PS2 mice may be optimal for longitudinal amyloid-PET monitoring in planned interventions studies

Automated Spatial Brain Normalization and Hindbrain White Matter Reference Tissue Give Improved [F-18]-Florbetaben PET Quantitation in Alzheimer's Model Mice

Preclinical PET studies of 13-amyloid (A beta) accumulation are of growing importance, but comparisons between research sites require standardized and optimized methods for quantitation. Therefore, we aimed to evaluate systematically the (1) impact of an automated algorithm for spatial brain normalization, and (2) intensity scaling methods of different reference regions for A beta-PET in a large dataset of transgenic mice. PS2APP mice in a 6 week longitudinal setting (N = 37) and another set of PS2APP mice at a histologically assessed narrow range of A beta burden (N = 40) were investigated by florbetaben PET Manual spatial normalization by three readers at different training levels was performed prior to application of an automated brain spatial normalization and inter -reader agreement was assessed by Fleiss Kappa (kappa). For this method the impact of templates at different pathology stages was investigated. Four different reference regions on brain uptake normalization were used to calculate frontal cortical standardized uptake value ratios (SUVRc-rx/REF) relative to raw SUVCTX. Results were compared on the basis of longitudinal stability (Cohen's d), and in reference to gold standard histopathological quantitation (Pearson's R). Application of an automated brain spatial normalization resulted in nearly perfect agreement (all If kappa >= 0.99) between different readers, with constant or improved correlation with histology. Templates based on inappropriate pathology stage resulted in up to 2.9% systematic bias for SUVRc-Fx, /REF " All SUVRG-Fx, /REF methods performed better than SUVGTx both with regard to longitudinal stability (d >= 1.21 vs. d = 0.23) and histological gold standard agreement (R >= 0.66 vs. R >= 0.31). Voxel-wise analysis suggested a physiologically implausible longitudinal decrease by global mean scaling. The hindbrain white matter reference (R-mean = 0.75