Organic Food and Health: A new project to study the effects of plant cultivation methods (organic and conventional) on nutritional value, health and reproduction in an animal experiment

Many consumers believe that food from plants grown under certain conditions, such as organic agriculture, will benefit health more than conventional food. This cannot be determined simply by analysing the material, since our understanding of the connections between food components and health is still to imprecise for such a purpose. Rather than waiting until basic research provides the knowledge needed for this approach, in the spring of 2001 we have initiated a project to study physiological effects of plant quality directly, in an animal experiment. The following cultivation treatments are used to grow plants that are typical ingredients for a human diet (potato, mature peas, kale, spring wheat, oilseed rape, carrots and apples): 1. A model of a distinct conventional cultivation system, with high input of mineral nutrients and use of as much pesticides as is allowed. 2. A model of a distinct organic cultivation system, with low input of organic plant nutrients and no use of pesticides. 3. A combination of model 1 and 2, with low input of nutrients and use of pesticides. The materials from each cultivation treatment will be thoroughly characterised, by measuring contents of nutrients (protein, minerals, energy content, vitamins), the biological value of major protein sources of feed plants will be assessed, selected secondary metabolites including known anti-nutrients will be measured and other quality indicators will be assessed including biocrystallization. Based on these results, 3 feed mixtures will be prepared, either based on defined weight percentages of each material from each treatment, or, if large variation in biological value is found, one or two feed mixtures can be adjusted to provide the same availability of protein and energy as the reference treatment (model 1). Potato, mature peas and kale will be cooked and freeze-dried, wheat is ground and baked to biscuits, oil is produced from the rapeseed, and raw carrots and apples are shredded and freeze dried, before feed pellets with the desired composition are prepared from the material. Three groups of rats are each provided one of the dietary treatments during 2.5 generation, and reproductive characteristics and performance are recorded. Subgroups of the last generation are selected for an intensive study in which uptake and excretion of energy and protein and selected micronutrients are determined. Respiration trials are performed to assess the energy metabolism, and simultaneous measurements of the activity levels of the rats are performed. In addition, blood and tissue samples of the rats will be obtained to study the effect of the dietary treatments on the immunological and antioxidant status of the rats. Data from the experiments are assembled and analysed using relevant statistical models, and the relationship to the nutritional characteristics of the plant material is described. Funding for the core project for a 4-year period is secured from the Danish Research Centre for Organic Farming (DARCOF). However, the intention is to provide a platform for international collaboration, since the well-documented material of plants and animals can provide multiple opportunities for associated projects. To investigate other aspects of plant composition or health than what is foreseen in the present project, or to follow up on it with additional experiments

Colloquium: Atomic spin chains on surfaces

In the present Colloquium, we focus on the properties of 1-D magnetic systems on solid surfaces. From the emulation of 1-D quantum phases to the potential realization of Majorana edge states, spin chains are unique systems to study. The advent of scanning tunnelling microscope (STM) based techniques has permitted us to engineer spin chains in an atom-by-atom fashion via atom manipulation and to access their spin states on the ultimate atomic scale. Here, we present the current state of research on spin correlations and dynamics of atomic spin chains as studied by the STM. After a brief review of the main properties of spin chains on solid surfaces, we classify spin chains according to the coupling of their magnetic moments with the holding substrate. This classification scheme takes into account that the nature and lifetimes of the spin-chain excitation intrinsically depend on the holding substrate. We first show the interest of using insulating layers on metals, which generally results in an increase in the spin state's lifetimes such that their quantized nature gets evident and they are individually accessible. Next, we show that the use of semiconductor substrates promises additional control through the tunable electron density via doping. When the coupling to the substrate is increased for spin chains on metals, the substrate conduction electron mediated interactions can lead to emergent exotic phases of the coupled spin chain-substrate conduction electron system. A particularly interesting example is furnished by superconductors. Magnetic impurities induce states in the superconducting gap. Due to the extended nature of the spin chain, the in-gap states develop into bands that can lead to the emergence of 1-D topological superconductivity and, consequently to the appearance of Majorana edge states

Überwachung von NSO-Heterocyclen an Teeröl-kontaminierten Standorten

Kurzfassung: An Teeröl-kontaminierten Standorten kommen neben Schadstoffen wie homocyclischen aromatischen Kohlenwasserstoffen auch NSO-heterocyclische Kohlenwasserstoffe vor, die bislang nicht routinemäßig überwacht werden, obwohl die Bundes-Bodenschutz- und Altlastenverordnung dies explizit fordert. Im Zuge des BMBF-Förderschwerpunktes "KORA - Kontrollierter natürlicher Rückhalt und Abbau von Schadstoffen bei der Sanierung kontaminierter Grundwässer und Böden” wurden mehrere Teeröl-kontaminierte Standorte in Deutschland untersucht und in Verbindung mit weiteren Literaturdaten zu Toxizität und Persistenz Prioritärsubstanzen abgeleitet, die wir empfehlen, in die Routineanalytik zur Beurteilung von Natural Attenuation- Prozessen aufzunehmen. Für den Nachweis und die Quantifizierung der Verbindungen wurden verschiedene Analysemethoden entwickel