Untersuchungen zum Amphibienbestand eines Feuchtgebietes in Osnabrück : mit 2 Tabellen

Im Rahmen der Projekt-Lehrveranstaltung "Angewandte Biotopforschung" an der Universität Osnabrück wurden im Jahre 1987 in einem kleinen Feuchtgebiet des Osnabrükker Stadtteils Atter Untersuchungen an den dortigen Amphibienbeständen durchgeführt. Dabei konnten 9 Arten nachgewiesen werden: Erdkröte (Bufo bufo), Grasfrosch (Rana temporaria), Moorfrosch (Rana arvalis), Wasserfrosch (Rana esculenta), Laubfrosch (Hyla arborea), Teichmolch (Triturus vulgaris), Fadenmolch (T. helveticus), Bergmolch (T. alpestris) und Kammolch (T. cristatus). 4 der Arten stehen auf der Roten Liste. Bedingt durch das kalte Frühjahr 1987 erfolgten die Wanderungen zu den Laichgewässern sehr spät. Negative Entwicklungen und Einflüsse, die im Gebiet beobachtbar sind, sollten durch die Ausweisung als "Flächenhaftes Naturdenkmal" eingedämmt werden. Über einen Pflege- und Entwicklungsplan wäre das Gelände zu verbessern

XeNA: an automated ‘open-source’ 129Xe hyperpolarizer for clinical use

Here we provide a full report on the construction, components, and capabilities of our consortium’s “open-source” large-scale (~ 1 L/h) 129Xe hyperpolarizer for clinical, pre-clinical, and materials NMR/MRI (Nikolaou et al., Proc. Natl. Acad. Sci. USA, 110, 14150 (2013)). The ‘hyperpolarizer’ is automated and built mostly of off-the-shelf components; moreover, it is designed to be cost-effective and installed in both research laboratories and clinical settings with materials costing less than $125,000. The device runs in the xenon-rich regime (up to 1800 Torr Xe in 0.5 L) in either stopped-flow or single-batch mode—making cryo-collection of the hyperpolarized gas unnecessary for many applications. In-cell 129Xe nuclear spin polarization values of ~ 30%–90% have been measured for Xe loadings of ~ 300–1600 Torr. Typical 129Xe polarization build-up and T1 relaxation time constants were ~ 8.5 min and ~ 1.9 h respectively under our spin-exchange optical pumping conditions; such ratios, combined with near-unity Rb electron spin polarizations enabled by the high resonant laser power (up to ~ 200 W), permit such high PXe values to be achieved despite the high in-cell Xe densities. Importantly, most of the polarization is maintained during efficient HP gas transfer to other containers, and ultra-long 129Xe relaxation times (up to nearly 6 h) were observed in Tedlar bags following transport to a clinical 3 T scanner for MR spectroscopy and imaging as a prelude to in vivo experiments. The device has received FDA IND approval for a clinical study of chronic obstructive pulmonary disease subjects. The primary focus of this paper is on the technical/engineering development of the polarizer, with the explicit goals of facilitating the adaptation of design features and operative modes into other laboratories, and of spurring the further advancement of HP-gas MR applications in biomedicine

NMR hyperpolarization techniques of gases

Nuclear spin polarization can be significantly increased through the process of hyperpolarization, leading to an increase in the sensitivity of nuclear magnetic resonance (NMR) experiments by 4–8 orders of magnitude. Hyperpolarized gases, unlike liquids and solids, can often be readily separated and purified from the compounds used to mediate the hyperpolarization processes. These pure hyperpolarized gases enabled many novel MRI applications including the visualization of void spaces, imaging of lung function, and remote detection. Additionally, hyperpolarized gases can be dissolved in liquids and can be used as sensitive molecular probes and reporters. This Minireview covers the fundamentals of the preparation of hyperpolarized gases and focuses on selected applications of interest to biomedicine and materials science

Ecological modeling of small mammal populations at hazardous waste sites : [an honors thesis (HONRS 499)]

This study is concerned with one small but important part of the Comprehensive Environmental Response, Compensation, and Liability Act (the CERCLA process). It involves learning about the food, habitat, life, and habits of some small mammal species of deciduous forest and grassland ecosystems, how they affect the ecosystem under natural conditions, how they are affected by chemical contaminants, and incorporating this knowledge into ecological modeling efforts at contaminated sites. I will be identifying potential effects that toxic chemicals have on a general contaminated site based on the nature of the contaminant and the use of research results from small mammal studies. The information can be sued to evaluate an existing site to determine what the possible effects of a contaminant are to that site, small mammals at that site, and the entire ecosystem in general.Thesis (B.?.)Honors Colleg

Surface studies using optical pumping magic angle spinning nuclear magnetic resonance

Nuclear Magnetic Resonance (NMR) has proven to be a very valuable technique for the study of a variety of compounds and materials due to its chemical selectivity, non-destructive detection, and quantitative ability. However, due to low sensitivity and lack of surface selectivity, NMR has not been used a great deal for the study of surfaces and interfaces. This thesis discusses a method known as optical pumping magic angle spinning NMR using hyperpolarized xenon to examine surfaces. The optical pumping process is described as well as the uses of hyperpolarized xenon. Experiments detecting hyperpolarized xenon and transferring polarization of hyperpolarized xenon to surface nuclei are described. Two major methods of polarization transfer, Spin Polarization Induced Nuclear Overhauser Effect (SPINOE) and Cross-Polarization (CP), are described in detail and compared. More complex two-dimensional experiments are described. Finally, new instrumentation is developed to further enhance the polarization of xenon used in NMR experiments