10 research outputs found
Thomas Manns streitbarer Nachbar
Bernard von Brentano (1901-1964) verbrachte seine iterarische Blütezeit in Küsnacht. Sein grosser Roman «Theodor Chindler» erschien in Zürich
The third cycle of the Bologna-Prozess - A critical analysis on the practise of a european aducational program
Die Arbeit untersucht die, durch den Bologna-Prozess angestrebte Förderung der Doktorandenausbildung für Fachhochschul-Master-Absolventen an deutschen Universitäten und die reale Umsetzung.The work analyses the pursuit of the Bologna-Process to improve the quality of doctoral education for the master´s graduates of higher education programs (Fachhochschule)in German universities. The realisation of this pursuit has also been analysed in this work
10-year Characteristics of Moisture Source Regions and Their Potential Effect on Seasonal Isotopic Signatures of δ18O in Tropical Trees of Southern Ecuador
Ratios of stable oxygen isotopes in tree rings (δ18O) are a valuable proxy for reconstructing past climates. Such reconstructions allow us to gain better knowledge of climate dynamics under different (eg warmer) environmental conditions, which also forms the basis for effective risk management. The latter aspect is particularly relevant for our study site on the western flanks of the Andes in Southern Ecuador, since the region is frequently affected by droughts and heavy precipitation events during the rainy season (January to April), leading to enormous social and economic losses. In particular, we focus on precipitation amounts and moisture source regions as they are known to influence the δ18O signature of tree rings. Moisture source regions are based on 240 h backward trajectories that were calculated with the trajectory model LAGRANTO for the rainy seasons 2008 to 2017. A moisture source diagnostic was applied to the air parcel pathways. The resulting moisture source regions were analyzed by calculating composites based on precipitation amounts, season, and calendar year. The precipitation amounts were derived from data of a local Automatic Weather Station (AWS). The analysis confirms that our study site receives its moisture both, from the Atlantic and the Pacific Oceans. Heavy precipitation events are linked to higher moisture contributions from the Pacific, and local SST anomalies along the coast of Ecuador are of higher importance than those off the coast toward the central Pacific. Moreover, we identified increasing moisture contributions from the Pacific over the course of the rainy season. This change and also rain amount effects are detectable in preliminary data of δ18O variations in tree rings of Bursera graveolens. These signatures can be a starting point for investigating atmospheric and hydroclimatic processes, which trigger δ18O variations in tree rings, more extensively in future studies
Bioactive S-alk(en)yl cysteine sulfoxide metabolites in the genus Allium: the chemistry of potential therapeutic agents
S-Alk(en)yl cysteine sulfoxides are odourless, non-protein sulfur amino acids typically found in members of the family Alliaceae and are the precursors to the lachrymatory and flavour compounds found in the agronomically important genus Allium. Traditionally, Allium species, particularly the onion (Allium cepa) and garlic (A. sativum), have been used for centuries in European, Asian and American folk medicines for the treatment of numerous human pathologies, however it is only recently that any significant progress has been made in determining their mechanisms of action. Indeed, our understanding of the role of Allium species in human health undoubtedly comes from the combination of several academic disciplines including botany, biochemistry and nutrition. During tissue damage, S-alk(en)yl cysteine sulfoxides are converted to their respective thiosulfinates or propanethial-S-oxide by the action of the enzyme alliinase (EC 4.4.1.4). Depending on the Allium species, and under differing conditions, thiosulfinates can decompose to form additional sulfur constituents including diallyl, methyl allyl, and diethyl mono-, di-, tri-, tetra-, penta-, and hexasulfides, the vinyldithiins and (E)- and (Z)-ajoene. Recent reports have shown onion and garlic extracts, along with several principal sulfur constituents, can induce phase II detoxification enzymes like glutathione-5-transferases (EC 2.5.1.18) and quinone reductase (QR) NAD(P)H: (quinine acceptor) oxidoreductase (EC 1.6.99.2) in mammalian tissues, as well as also influencing cell cycle arrest and apoptosis in numerous in vitro cancer cell models. Moreover, studies are also beginning to highlight a role of Allium-derived sulfur compounds in cardiovascular protection. In this review, we discuss the chemical diversity of S-alk(en)yl cysteine sulfoxide metabolites in the context of their biochemical and pharmacological mechanisms. © The Royal Society of Chemistry 2005