Mesoporous ordered silica structures modified by metal organic reagents and their application in catalytic Michael additions

Periodic mesoporous silica was modified with metal organic reagents via direct surface substitution reactions, thus introducing functional groups into the channels of the structure. Using materials functionalised with basic aromatic molecules as catalysts, the efficient Michael addition of diethyl malonate to trans-β-nitrostyrene was achieved. The catalysts anchored to the silica surface show high activity in the catalytic process even at low concentrations and low temperatures. The catalysts also prove to be stable during many recycling procedures. In combination with the remarkably reduced cost for the synthesis of these solid bases, the new hybrid systems are promising candidates for a new generation of catalysts.     

An English asylum in Africa: Space and order in Valkenberg Asylum.

The authors explore the use of space within and outside the buildings of Valkenberg, a Cape Colonial asylum. Valkenberg's design was conditioned by a complex interplay of factors: the way insanity itself was viewed by the colonial government, developments in medical knowledge, social-economic relations in the colonial setting, and practical forms of treatment. The internal structuring of space within the building, and the way the building was situated in the landscape, are graphic representations of 4 influences, in tension with each other: determination to reform the colony's psychiatric practices, a desire to reproduce British institutions in colonial settings, a stigmatizing fear of insanity and lunatics, and a desire to maintain strict segregation between White and Black staff and patients. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An investigation into the synthesis of polycarbazole squaraine derivatives

The polycondensation of squaric acid with 1,2-(9-Ethylcarbazol-3-yl)ethene and N-ethyliminostilbene in polyphosphoric acid yielded insoluble polymers which included substituted phosphate groups on the phenyl rings. The presence of phosphorus in these polymers was identified using solid-state ³¹P NMR and EDAX techniques. Furthermore the phosphate groups were not ionic, hence no charge-balancing anions were present. Both polymers did not electrically conduct but exhibited dielectric breakdown values of 0.1 and 0.06 MV cm⁻¹ respectively. Received: 16 December 1996/Revised: 10 March 1997/Accepted: 10 March 1997     

Production of mycotoxins byFusarium species isolated in Germany

Summary Cultures ofFusarium tricinctum 434 formed large amounts of the trichothecene mycotoxins deoxynivalenol (DON) and 3-acetyldeoxynivalenol (AcDON), as well as the macrocyclic secondary metabolite zearalenone on moistened, autoclaved maize, rice and oats. The formation of zearalenone was low, with levels from 15 to 72 mg/kg as compared to the trichothecene production with maximum quantities of 917 mg/kg of AcDON on rice and 750 mg/kg DON on oats. In the cultures ofF. graminearum 183, total mycotoxin amounts found were lower, with maximum levels of zearalenone up to 150 mg/kg and AcDON up to 160 mg/kg on rice. DON, however, was produced in quantities of about 740 mg/kg on rice.

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Produktion von Mykotoxinen durch in Deutschland isolierte Fusarium-Arten1. Zeitverlauf der Deoxynivalenol-, 3-Acetyldeoxynivalenol-, und Zearalenon-Bildung auf festen Substraten

Zusammenfassung Kulturen vonFusarium tricinctum 434 bildeten auf feuchtem, autoklaviertem Mais, Reis bzw. Hafer relativ hohe Mengen der Trichothecen-Mykotoxine Deoxynivalenol (DON) und 3-Acetyldeoxynivalenol (AcDON) sowie das zu den makrocyclischen Lactonen zählende Mykotoxin Zearalenon. Die Zearalenonbildung war mit Werten von 15 bis 72 mg/kg gegenüber der Trichothecenproduktion mit maximal 917 mg/kg AcDON auf Reis und 750 mg/kg DON auf Hafer deutlich niedriger. In den Kulturen vonF. graminearum 183 wurden insgesamt geringere Toxinmengen gefunden mit maximalen Zearalenon-konzentrationen bis zu 150 mg/kg sowie AcDON Mengen bis zu 160 mg/kg auf Reis. Dagegen erreichte die DON-Bildung auf Reis 740 mg/kg.