Studium der lebenden radikalischen Polymerisation mit der Differential Scanning Calorimetry (DSC)

The living radical polymerization of styrene, some styrene-analogous vinyl monomers as well as methyl methacrylate (MMA) and butyl methacrylate (BuMA) was investigated with a differential scanning calorimeter. The ability to polymerize was estimated by dynamic measurements, showing that p-methylstyrene, p-chlorostyrene, 3,4-dimethoxystyrene and 4-vinylpyridine polymerize in the presence of 2,2,6,6-tetramethyl-1-piperidine-N-oxyl (TEMPO) while MMA and BuMA do not. Isothermal measurements revealed an activation energy of E_A = 81 kJ mol^–1 for thermal bulk polymerization of styrene and values of E_A = 78–94 kJ mol^–1 were measured with different iniferter systems. These polymerizations have induction times which depend on the reaction temperature and the initial concentration of the iniferter systems. An influence of the kind of nitroxyl radical on the induction times was not observed.     

The Chemistry of the Postpharyngeal Gland of Female European Beewolves

Females of the European beewolf, Philanthus triangulum, possess a large glove-shaped gland in the head, the postpharyngeal gland (PPG). They apply the content of the PPG to their prey, paralyzed honeybees, where it delays fungal infestation. Here, we describe the chemical composition of the gland by using combined GC-MS, GC-FTIR, and derivatization. The PPG of beewolves contains mainly long-chain unsaturated hydrocarbons (C23–C33), lower amounts of saturated hydrocarbons (C14–C33), and minor amounts of methyl-branched hydrocarbons (C17–C31). Additionally, the hexane-soluble gland content is comprised of small amounts of an unsaturated C25 alcohol, an unknown sesquiterpene, an octadecenylmethylester, and several long-chain saturated (C25, C27) and unsaturated (C23–C27) ketones, some of which have not yet been reported as natural products. Surprisingly, we found a dimorphism with regard to the major component of the PPG with some females having (Z)-9-pentacosene, whereas others have (Z)-9-heptacosene as their predominant component. The biological relevance of the compounds for the prevention of fungal growth on the prey and the significance of the chemical dimorphism are discussed.     

Production and processing of foods as core aspects of nutrition-sensitive agriculture and sustainable diets

Some forms of malnutrition are partly due to agriculture not having nutrient outputs as an explicit goal. A better understanding of what is required from agricultural production and food processing for healthy and sustainable diets is needed. Besides nutritional quality or nutrient output, important factors are: water, soil, health hazards, agrobiodiversity and seasonality. Therefore, possible interactions among constituents of the food chain – human health, the environment, knowledge and education – should be considered from a systemic perspective. Nutrition-sensitive agriculture needs to consider and understand the role of biodiversity in improving dietary quality and dietary diversity as well as seasonality in food supply. Apart from improving agricultural systems in order to close the nutrition gap, efficient storage and food processing technologies to prolong shelf-life are required. If processing is poor, high food losses can cause food insecurity or increase the risk of producing unsafe and unhealthy food. Food storage and processing technologies, particularly at household level, are challenging and often not applicable to traditional crops. In order to achieve the aims of nutrition-sensitive agriculture, it is necessary to comprehend its complexity and the factors that influence it. This will require a trans-disciplinary approach, which will include the three sectors agriculture, nutrition and health at research, extension and political levels. Ensuring that farmers are knowledgeable about production systems, which sustainably provide adequate amounts of nutritious food while conserving the environment is an essential part of nutrition-sensitive agriculture. At the same time, for the benefits of nutrition-sensitive agriculture to be realized, educated consumers are required who understand what constitutes a healthy and sustainable diet.     

Supporting casual interactions between board games on public tabletop displays and mobile devices

As more interactive surfaces enter public life, casual interactions from passersby are bound to increase. Most of these users can be expected to carry a mobile phone or PDA, which nowadays offers significant computing capabilities of its own. This offers new possibilities for interaction between these users’ private displays and large public ones. In this paper, we present a system that supports such casual interactions. We first explore a method to track mobile phones that are placed on a horizontal interactive surface by examining the shadows which are cast on the surface. This approach detects the presence of a mobile device, as opposed to any other opaque object, through the signal strength emitted by the built-in Bluetooth transceiver without requiring any modifications to the devices’ software or hardware. We then go on to investigate interaction between a Sudoku game running in parallel on the public display and on mobile devices carried by passing users. Mobile users can join a running game by placing their devices on a designated area. The only requirement is that the device is in discoverable Bluetooth mode. After a specific device has been recognized, a client software is sent to the device which then enables the user to interact with the running game. Finally, we explore the results of a study which we conducted to determine the effectiveness and intrusiveness of interactions between users on the tabletop and users with mobile devices.     

Co-oxidation of carotene and crocin by soyabean lipoxygenase isoenzymes

Summary Three lipoxygenases that occur in soya beans were separated chromatographically. L-1 (optimum pH = 9.0), L-2 (pH 6.5), L-3 (pH 6.5). The velocities with which these enzymes co-oxidise-carotene or Crocin in the presence of linoleic acid or linoleyl sulphate weremeasured. The carotenoid turnover was related to each lipoxygenase activity.-carotene/linoleic acid = 55% (L-2), 43% (L-3), 6% (L-1), Crocin/linoleic acid = 17,8% (L-2), 14,3% (L-3), 3.3% (L-1), crocin/linoleyl sulphate = 24% (L-3), 4,2% (L-1).The relationship between the reaction rate of the Crocin bleaching and the concentrations of the enzyme, Crocin and linoleic acid was determined. To explain the differences between the pH-6.5 (L-2, L-3) and the alkaline (L-1) lipoxygenases it is supposed that L-2 and L-3 form specially active radicals that are able to co-oxidise polyenes. Both enzymes possess a hydrophobic bonding position, in the neighbourhood of the active site, for-carotene.

---

Co-oxidation von Carotin und Crocin durch Lipoxygenase-Isoenzyme aus der Sojabohne

Zusammenfassung Drei in Sojabohnen vorkommende Lipoxygenasen wurden chromatographisch getrennt: L-1 (pH-Optimum 9,0), L-2 (pH 6,5), L-3 (pH 6,5). Gemessen wurden die Geschwindigkeiten mit denen diese Enzyme-Carotin oder Crocin in Gegenwart von Linolsäure oder Linoleylsulfat co-oxydieren. Die Carotinoid-Umsätze wurden auf die jeweilige Lipoxygenase-Aktivität bezogen.-Carotin/Linolsäure: 55% (L-2), 43% (L-3), 6% (L-1), Crocin/Linolsäure: 17,8% (L-2),14,3% (L-3),3,3% (L-1), Crocin/Linoleylsulfat: 24% (L-3), 4,2% (L-1).Für die Crocin-Bleichung wurde die Abhängigkeit der Reaktionsgeschwindigkeit von der Enzym-, Crocin- und Linolsäure-Konzentration bestimmt.Zur Erklärung der Unterschiede zwischen den pH 6,5- (L-2, L-3) und der alkalischen Lipoxygenase (L-1) wird angenommen: L-2 und L-3 bilden besonders aktiv Radikale, welche die Polyene co-oxydieren können. Beide Enzyme besitzen in der Nähe des aktiven Zentrums eine hydrophobe Bindungsstelle für das-Carotin.

---

---

We are grateful to the Deutsche Forschungsgemeinschaft Bonn-Bad Godesberg for supporting this work.     

Does precontemplation represent a homogeneous stage category? A latent class analysis on German smokers.

The authors examined the subtype structure of smokers classified in the precontemplation stage of change within the transtheoretical model. From a general practice-based sample of 1,499 daily smoking patients from Germany (participation rate 80%), they used a subgroup of 929 smokers who were classified in the precontemplation stage and applied latent class analysis, using the pros and cons of nonsmoking and smoking cessation self-efficacy as the defining variables. Cross-sectional validation of the emerging classes was based on smoking behavior and processes of change variables. For longitudinal validation, generalized estimation equation analyses were used on motivational and abstinence criteria from 6-, 12-, 18-, and 24-month follow-ups. A 4-class model best represented the data. Three subtypes (labeled progressive, immotive, and disengaged pessimistic) were similar to clusters identified in U.S. studies. The 4th (disengaged optimistic), by contrast, was reminiscent of a type that had previously only emerged in a Dutch study. Cross-sectional and longitudinal validation results confirmed the distinctiveness and predictive power of the classes. The findings highlight the importance of tailoring interventions for smoking behavior change to the needs of different subgroups of precontemplating smokers. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Toxicity of different wheat gliadins in coeliac disease

Summary To determine the toxic effect of different gliadins on coeliac patients, which has been variably assessed in the literature, wheat prolamines (gliadin) were separated into the main fractions-, -, -, and-gliadins by chromatography on Sulfopropyl Sephadex C-50. The chemical compositions of the gliands were characterized by polyacrylamide gel electrophoresis, amino-acid analysis, determination of amide nitrogen and peptide maps.The peptide fractions B2 and B3 were isolated from the gliadins by a peptic tryptic digestion, ultrafiltration and gel filtration on Sephadex G-50.The gliadins and the peptide fractions were examined for coeliac activity by immunological tests (LIF tests) and by organ-culture tests.The results show that the peptide fractions are generally more active than their respective gliadins. The peptide fractions of all gliadins have a coeliac-specific toxic effect; their activities correlate with the chemical composition of the gliadins.

---

Untersuchungen von Gliadinfraktionen des Weizens auf Cöliakieaktivität

Zusammenfassung Zur Überprufung der teilweise widersprüchlichen Angaben in der Literatur über die cöliakieauslösende Wirkung einzelner Gliadinfraktionen wird Weizenprolamin (Gliadin) durch Ionenaustauschchromatographie an Sulfopropyl-Sephadex C-50 in die Hauptfraktionen-, -, - und-Gliadin aufgetrennt. Die Gliadine werden durch PAG-Elektrophorese, Aminosäureanalyse, Amid-N-Bestimmung und über die nach partieller enzymatischer Hydrolyse erhaltenen Peptidmuster in ihrer chemischen Zusammensetzung charakterisiert. Durch peptisch-tryptische Partialhydrolyse, Ultrafiltration und Gelchromatographie an Sephadex G-50 werden aus den einzelnen Gliadinen die Peptidfraktionen 132 und 133 gewonnen. Die Protein- und Peptidfraktionen werden in einem immunologischen Test (LIF-Test) bzw. in einem Organkultur-Test auf Cöliakieaktivität untersucht.Die Ergebnisse zeigen, daß die Peptidfraktionen durchweg größere Aktivität haben als die entsprechenden Proteine, und daß von den Peptidfraktionen aller Gliadine eine cöliakiespezifische Wirkung ausgeht, wobei die Aktivität mit der chemischen Zusammensetzung der Gliadine korreliert ist.

---

---

Supported by a grant from Stiftung Volkswagenwerk