Decomposing data sets into skewness modes

We derive the nonlinear equations satisfied by the coefficients of linear combinations that maximize their skewness when their variance is constrained to take a specific value. In order to numerically solve these nonlinear equations we develop a gradient-type flow that preserves the constraint. In combination with the Karhunen-Lo\`eve decomposition this leads to a set of orthogonal modes with maximal skewness. For illustration purposes we apply these techniques to atmospheric data; in this case the maximal-skewness modes correspond to strongly localized atmospheric flows. We show how these ideas can be extended, for example to maximal-flatness modes.Comment: Submitted for publication, 12 pages, 4 figure

Silicon fractionation in Mollic Fluvisols along the Central Elbe River, Germany

Quantification of Si in its different forms in soil is a prerequisite to understand the geochemical distribution and fate of Si along with their driving biogeochemical processes. However, different Si fractions in floodplain soils have not been quantified yet, and little is known about the processes driving Si fractionation in these soils. The aim of this study was to clarify the processes that drive formation and distribution of Si among fractions in floodplain soils. We obtained and quantified these fractions using a sequential Si extraction method (Georgiadis et al., 2013) in three Mollic Fluvisols along the Central Elbe River. The highest Si proportion apart from the residual fraction was found in minerogenic amorphous silica (up to 5.6% of total Si), followed by Si occluded in pedogenic oxides and hydroxides (up to 0.7% of total Si). Silicon from biogenic amorphous silica amounted to 0.02-0.6% of total Si. The smallest proportion of Si was found in the mobile Si fraction and made up about 0.01% of the total Si. The results of this study demonstrate the importance of the soil water budget on the accumulation of easy-to-mobilise Si, Si occluded in pedogenic oxides and hydroxides and amorphous silica. Reductive dissolution of Fe and Mn oxides may induce Si release into the soil solution, subsequent oxidizing conditions may induce Si accumulation by adsorption, co-precipitation and occlusion of Si on/with newly formed Fe and Mn oxides. Accumulation of bio-opal after flooding may induce larger amounts of biogenic amorphous silica in floodplain soils than in terrestrial soils. Finally, floodplain soils may accumulate larger amounts of Si bound to occluded particulate SOM than terrestrial soils, which experience less input of particulate SOM than floodplain soils

The evolution of Runx genes I. A comparative study of sequences from phylogenetically diverse model organisms

BACKGROUND: Runx genes encode proteins defined by the highly conserved Runt DNA-binding domain. Studies of Runx genes and proteins in model organisms indicate that they are key transcriptional regulators of animal development. However, little is known about Runx gene evolution. RESULTS: A phylogenetically broad sampling of publicly available Runx gene sequences was collected. In addition to the published sequences from mouse, sea urchin, Drosophila melanogaster and Caenorhabditis elegans, we collected several previously uncharacterised Runx sequences from public genome sequence databases. Among deuterostomes, mouse and pufferfish each contain three Runx genes, while the tunicate Ciona intestinalis and the sea urchin Strongylocentrotus purpuratus were each found to have only one Runx gene. Among protostomes, C. elegans has a single Runx gene, while Anopheles gambiae has three and D. melanogaster has four, including two genes that have not been previously described. Comparative sequence analysis reveals two highly conserved introns, one within and one just downstream of the Runt domain. All vertebrate Runx genes utilize two alternative promoters. CONCLUSIONS: In the current public sequence database, the Runt domain is found only in bilaterians, suggesting that it may be a metazoan invention. Bilaterians appear to ancestrally contain a single Runx gene, suggesting that the multiple Runx genes in vertebrates and insects arose by independent duplication events within those respective lineages. At least two introns were present in the primordial bilaterian Runx gene. Alternative promoter usage arose prior to the duplication events that gave rise to three Runx genes in vertebrates

Updates in Mechanical Thrombectomy

Strokes are a major source of morbidity and mortality worldwide. The long-standing gold standard in stroke therapy, intravenous administration of tissue plasminogen activator (tPA), is limited by strict timing parameters and modest efficacy in large strokes caused by thrombi in the proximal cerebral vasculature. Multiple recent randomized controlled trials have demonstrated the efficacy of mechanical thrombectomy for patients with large vessel occlusions (LVOs). Recent clinical guidelines have been updated to include mechanical thrombectomy as a standard of care in properly selected stroke patients, with ongoing and future studies working to refine the optimal clinical and technical variables of this approach

The distribution of organic contaminant in aged tar-oil contaminated soils

One of the most common soil contamination sources in Germany are former manufactured gas plants. Many of them were destroyed during the World War II or abandoned in late XXth century. As the result a lot of potentially fertile soils were contaminated with specific viscous tar oil wastes. We studied a small tar oil waste basin. The age of the contamination was assessed to be at least 30 years. Natural attenuation processes resulted in formation of three soil layers. The upper layer (about 7cm in thickness) was rooted by weak grass vegetation and had features of newly formed humic-like organic matter. The total petroleum hydrocarbon (TPH) content was 28 mg/g. Below this layer (7-15 cm) we observed the most contaminated stratum with 90 mg/g TPH. The layer underneath (15-22 cm) had smaller concentrations of 16 mg/g TPH. Underlying strata had no visual evidence of contamination. Microbial biomass analyses showed that the most contaminated layer had 2-3 times more bacteria than the control soils. We suppose that during the aging processes a new microbial consortium capable of transforming high-molecular weight hydrocarbons has developed. Optical and FTIR-microscopy allowed us to observe the microstructure of contaminated soils. The tar oil formed dense spherical aggregates within the soil, which contained almost no mineral phase. Root channels and macropores were identified as preferential pathflows for the viscous tar oil, as they seemed to be coated with hydrocarbons even in less contaminated underlayers. We presume that open pores could initially act as remediation spots with aerobic conditions. Future oil migration might clog these pores, cease oxidation processes and slow down the remediation. High contents of total Fe and both dithionite-extractable and oxalate-extractable Fe as well as the occurrence of large siderite crystals in the most contaminated layer suggested that there might be isolated zones with anaerobic conditions to support this assumption

Rare glutamic acid methyl ester peptaibols from Sepedonium ampullosporum Damon KSH 534 exhibit promising antifungal and anticancer activity

Fungal species of genus Sepedonium are rich sources of diverse secondary metabolites (e.g., alkaloids, peptaibols), which exhibit variable biological activities. Herein, two new peptaibols, named ampullosporin F (1) and ampullosporin G (2), together with five known compounds, ampullosporin A (3), peptaibolin (4), chrysosporide (5), c(Trp-Ser) (6) and c(Trp-Ala) (7), have been isolated from the culture of Sepedonium ampullosporum Damon strain KSH534. The structures of 1 and 2 were elucidated based on ESI-HRMS(n) experiments and intense 1D and 2D NMR analyses. The sequence of ampullosporin F (1) was determined to be Ac-Trp(1)-Ala(2)-Aib(3)-Aib(4)-Leu(5)-Aib(6)-Gln(7)-Aib(8)-Aib(9)-Aib(10)-GluOMe(11)-Leu(12)-Aib(13)-Gln(14)-Leuol(15), while ampullosporin G (2) differs from 1 by exchanging the position of Gln(7) with GluOMe(11). Furthermore, the total synthesis of 1 and 2 was carried out on solid-phase to confirm the absolute configuration of all chiral amino acids as L. In addition, ampullosporin F (1) and G (2) showed significant antifungal activity against B. cinerea and P. infestans, but were inactive against S. tritici. Cell viability assays using human prostate (PC-3) and colorectal (HT-29) cancer cells confirmed potent anticancer activities of 1 and 2. Furthermore, a molecular docking study was performed in silico as an attempt to explain the structure-activity correlation of the characteristic ampullosporins (1–3)

Beeinflusst die Landnutzungsintensität im Grünland die mikrobielle Besiedlung von organo-mineralischen Komplexen sowie die Ressourcenverteilung innerhalb der mikrobiellen Bodengemeinschaft?

Minerale bzw. die Oberflächen von organo-mineralischen Komplexen sind neben der Rhizo- und Detritussphäre mikrobielle ´Hot Spots` in Böden. Die Besiedlung dieser Mikrohabitate ist abhängig von biotischen und abiotischen Eigenschaften des Bodens. Es ist daher anzunehmen, dass unterschiedliche mikrobielle Ressourcennutzungsstrategien zur räumlichen Verteilung von Bodenmikroorganismen auf lokaler Ebene beitragen können. Bis heute ist unklar, inwiefern sich dies auf die Struktur und Funktion der mikrobiellen Gemeinschaft unter Freilandbedingungen in Grünlandböden auswirkt. Im Rahmen der Biodiversitäts-Exploratorien versuchen wir zwei Forschungsfragen zu beantworten 1) Welche Organismen sind beim Wurzelabbau in Grünlandböden unter verschiedenen Landnutzungsintensitäten die Hauptakteure? 2) Wer profitiert wann am meisten? Hierzu wurde innerhalb des Forschungsprojektes im September 2014 ein randomisiertes Feldexperiment mit Mikrokosmen auf 10 Flächen der Schwäbischen Alb angelegt. Die Flächen unterscheiden sich in ihrer Landnutzungsintensität (fünf Flächen mit hohem und fünf mit niedrigem LUI-Index), nicht aber hinsichtlich des Bodentyps (Rendzina). Befüllt wurde jeder Mikrokosmos mit einem standortangepassten Mineral-Wurzelgemisch bestehend aus: 71,4% Illit, 9,6% Goethit, 17% Quarz-Schluff und 2% Quarzsand sowie doppelt markierten Feinwurzeln, Dactylis glomerata/ Lolium perenne (13,1 Atom-% C-13 und 12,1 Atom-% N-15). Die Ernte der Mikrokosmen, des angrenzenden Bodens sowie der Vegetation direkt über den Mikrokosmen wird nach 1, 3, 6, 12 und 18 Monaten durchgeführt. Zur Beantwortung der Forschungsfragen werden a) die mikrobielle Gemeinschaftsstruktur mit Hilfe von CFE, PLFA und molekularbiologischen Methoden (qPCR), sowie b) das mikrobielle Nahrungsnetz mittels isotopischer Verfahren analysiert

Bildung und Eigenschaften anorganischer Kieselsäure-Schadstoffverbindungen im Boden

Verschiedene Studien demonstrieren den positiven Effekt von Si-Dünger auf die Widerstandsfähigkeit einiger Pflanzen gegenüber anorganischen Schadstoffen, wie Pb, Cd und Cu. Als eine der Ursachen wird die Schadstoffimmobilisierung nach Si-Zugabe durch eine Komplexierungsreaktion angesehen, sodass die Schadstoffe mit der Kieselsäure in einer für die Pflanze nicht verfügbaren Form gebunden werden. Dieser Prozess wurde jedoch bisher nicht systematisch untersucht und aufgeklärt. Das Hauptziel dieser Arbeit ist es die Prozesse der Immobilisierung von Pb, Cd und Cu im Boden mittels Kieselsäure zu klären. Dafür sollen die Interaktionen zur Bildung von Kieselsäure-Schadstoffverbindungen zwischen der gelösten Kieselsäure und den Metallkationen in wässriger Lösung in einer Reihe von Fällungsexperimenten untersucht werden. Im ersten Schritt wird die Bildung der Kieselsäure-Schadstoffverbindungen in wässriger Lösung bei variierenden Synthesebedingungen (Si-Metall-Verhältnis und Zeit) und Raumtemperatur untersucht. Für die Synthese werden Tetraethylorthosilikat (TEOS) als Si-Quelle sowie die drei gelösten Metallsalze Pb(NO3)2, Cd(NO3)2 bzw. Cu(NO3)2 verwendet. Zur Untersuchung der Selektivität des Si gegenüber den genannten Metallkationen wird TEOS zu einer äquimolaren Lösung aller drei Metalle gegeben. Die Erfassung der Zeitabhängigkeit des Partikelwachstums erfolgt mittels Entnahme eines 50 ml Aliquots an 10 unterschiedlichen Terminen. Nach Dialyse in Reinstwasser werden die Proben mittels dynamischer Lichtstreuung und Elektrophorese analysiert, um die Größenverteilung und die Ladung der kolloidalen Partikel zu ermitteln. Die Bestimmung der relativen Partikelkonzentration in den Suspensionen erfolgt durch Messung der optischen Dichte mittels UV/VIS-Spektroskopie. Die chemische Zusammensetzung der dialysierten Suspension wird mittels ICP-OES ermittelt. Die synthetisierten Verbindungen werden mittels FTIR- und 29Si-NMR-Spektroskopie charakterisiert