Methodische Weiterentwicklung der Laser-induzierten Breakdown-Detektion (LIBD) und ihre Anwendung auf kolloidchemische Fragestellungen

Die Laser-induzierte Breakdown-Detektion (LIBD) konnte in den letzten zwanzig Jahren zu einer etablierten Methode zur quantitativen Charakterisierung von Kolloiden in aquatischen Systemen entwickelt werden. Sie ermöglicht die Bestimmung eines mittleren Kolloid-Durchmessers und der Anzahl- sowie Massenkonzentration (bei bekannter Dichte der Kolloide) in bisher nicht erreichten Größen- und Konzentrationsbereichen. Das Detektionsspektrum der entwickelten Instrumentierung liegt im Bereich zwischen ~ 20 nm und 1000 nm, wobei die Nachweisgrenze abhängig vom Partikeldurchmesser im Bereich von wenigen ng/L (entspricht 1e8 Partikel/L für 20 nm-Kolloide) bis hin zu einigen mg/L (entspricht 1e7 Partikel/L für 1000 nm-Kolloide1) reicht. Damit weist die LIBD im Vergleich zu konkurrierenden Methoden auf Basis der Laserlichtstreuung eine um mehrere Größenordnungen höhere Nachweisempfindlichkeit auf, wodurch sie insbesondere bei der nicht-invasiven Charakterisierung von kolloidarmen System bzw. von Kolloiden (Nanopartikeln) unter 100 nm die Methode der Wahl ist. Ein Schwerpunkt in dieser Arbeit lag in der methodischen Weiterentwicklung auf Basis der bisherigen Funktionalitäten der am Institut entwickelten Anlage � sowohl bezüglich der Datenevaluation als auch der Benutzerfreundlichkeit und der Optimierung der Anlage für die Anwendung auf neue kolloidchemische Fragestellungen. Der zweite Schwerpunkt der Arbeit bestand darin, das hohe Potential der LIBD-Technik mit ihren erweiterten Funktionalitäten als kolloidanalytische Methode durch den Einsatz bei verschiedenen Fragestellungen der aquatischen Kolloidchemie zu belegen. Neben der Analyse des partikulären Austrags aus Recyclingmaterialien und der Untersuchung von biogenen Fällungsprozessen in natürlichen Gewässern wurden im Rahmen eines dreijährigen Forschungsprojekts Trinkwasseraufbereitungsverfahren auf Basis der Membranfiltrationstechnologie untersucht. Die Filtrationseffizienz und Filtratqualität wurde an vier verschiedenen Standorten, die eine klein- oder großtechnische Membrananlage besitzen, erstmals mittels NPA/LIBD untersucht, indem Membranzu- und Abläufe systematisch bezüglich ihres Kolloid-Inventars charakterisiert wurden. Des Weiteren erfolgten umfassende Unter¬suchungen zum Foulingpotential (Verblocken der Membranen) von natürlichen Rohwässern (d. h. ihre Tendenz zum Verblocken der mit den Rohwässern beaufschlagten Membranen) und zur Membranintegrität von Ultra- und Mikrofiltrationsmembranen

Surface wax in the ancestral grapevine Vitis sylvestris correlate with partial resistance to Powdery Mildew

Background Powdery Mildew of Grapevine belongs to the major diseases in viticulture and requires intensive use of fungicides. Genetic introgression of resistance factors from wild grapes from North America and, recently, China, has been successful, but wine made from those varieties is still confronted with low consumer acceptance, due to differences in taste. Results The current work explores the potential of Vitis vinifera sylvestris, the wild ancestor of domesticated Grapevine, with respect to containing Erysiphe necator, the causative agent of Powdery Mildew. Making use of a germplasm collection comprising the entire genetic variability remaining in Germany, we show that there is considerable genetic variation in the formation of leaf surface waxes exceeding wax formation in commercial varieties. Conclusions High wax formation correlates with reduced susceptibility to controlled infection with E. necator linked with perturbations of appressoria formation. We propose V. vinifera sylvestris as novel source for resistance breeding since it is genetically much closer to domesticated grapevine than the hitherto used sources from beyond the species barrier

Intercellular communication is required for trap formation in the nematode-trapping fungus Duddingtonia flagrans

Nematode-trapping fungi (NTF) are a large and diverse group of fungi, which may switch from a saprotrophic to a predatory lifestyle if nematodes are present. Different fungi have developed different trapping devices, ranging from adhesive cells to constricting rings. After trapping, fungal hyphae penetrate the worm, secrete lytic enzymes and form a hyphal network inside the body. We sequenced the genome of Duddingtonia flagrans, a biotechnologically important NTF used to control nematode populations in fields. The 36.64 Mb genome encodes 9,927 putative proteins, among which are more than 638 predicted secreted proteins. Most secreted proteins are lytic enzymes, but more than 200 were classified as small secreted proteins (< 300 amino acids). 117 putative effector proteins were predicted, suggesting interkingdom communication during the colonization. As a first step to analyze the function of such proteins or other phenomena at the molecular level, we developed a transformation system, established the fluorescent proteins GFP and mCherry, adapted an assay to monitor protein secretion, and established gene-deletion protocols using homologous recombination or CRISPR/Cas9. One putative virulence effector protein, PefB, was transcriptionally induced during the interaction. We show that the mature protein is able to be imported into nuclei in Caenorhabditis elegans cells. In addition, we studied trap formation and show that cell-to-cell communication is required for ring closure. The availability of the genome sequence and the establishment of many molecular tools will open new avenues to studying this biotechnologically relevant nematode-trapping fungus

An Attempt to Relate Oleogel Properties to Wax Ester Chemical Structures

Wax esters are considered to have a dominant contribution in the gelling properties of wax-based oleogels. To understand their gelling behavior, oleogels of seven different wax esters (total carbon number from 30 to 46; c = 10% [m/m]) in medium-chain triglycerides oil were characterized. Scanning electron microscopy revealed that wax esters crystallize in rhombic platelets with a thickness of 80 to 115 monomolecular layers. Bright field microscopy showed that the regularity and face length of the crystals increased with the total carbon number and molecular symmetry of the respective wax ester. Oscillatory rheology was used to characterize the gel rigidity (Gmax*). Here, wax ester oleogels with smaller total carbon numbers yielded higher Gmax* values than those of wax esters with higher total carbon numbers. The gel rigidity (Gmax*) inversely correlated with the crystal face length. Smaller and optically less well-defined platelets promoted higher gel rigidities. In the case of the microstructure of a specific oleogel composition being manipulated by a variation in the cooling rates (0.8; 5; 10 K/min), this relationship persisted. The information compiled in this manuscript further elucidates the crystallization behavior of wax esters in oleogels. This contributes to the understanding of the composition&ndash;structure&ndash;functionality relationship of wax-based oleogels supporting future food applications

RELEASE OF NANOPARTICLES FROM ION EXCHANGE RESINS AND THEIR DETECTION

WOS: 000307240300002Nanoparticles released from commercial ion exchange resins were analyzed by laser-induced breakdown detection (LIBD). It was shown that virgin resins release a considerable amount of nanoparticles which may harm sensitive production lines, if the resins are used without proper pretreatment. Particle release is reduced to below 1 ppb after regeneration and rinsing of the resins. However, the nanoparticle concentration can still be detected quantitatively by LIBD.LLP-Erasmus programWe thank the LLP-Erasmus program for the support of O. Arar in performing this research work at the Karlsruhe Institute of Technology (KIT). We are also deeply thankful to Prof. Wolfgang Holl, who gave valuable input to this work and who unfortunately died much too early in May 2010

Surface wax in the ancestral grapevine Vitis sylvestris correlate with partial resistance to Powdery Mildew

Abstract Background Powdery Mildew of Grapevine belongs to the major diseases in viticulture and requires intensive use of fungicides. Genetic introgression of resistance factors from wild grapes from North America and, recently, China, has been successful, but wine made from those varieties is still confronted with low consumer acceptance, due to differences in taste. Results The current work explores the potential of Vitis vinifera sylvestris, the wild ancestor of domesticated Grapevine, with respect to containing Erysiphe necator, the causative agent of Powdery Mildew. Making use of a germplasm collection comprising the entire genetic variability remaining in Germany, we show that there is considerable genetic variation in the formation of leaf surface waxes exceeding wax formation in commercial varieties. Conclusions High wax formation correlates with reduced susceptibility to controlled infection with E. necator linked with perturbations of appressoria formation. We propose V. vinifera sylvestris as novel source for resistance breeding since it is genetically much closer to domesticated grapevine than the hitherto used sources from beyond the species barrier

Electric Impedance Recording - A Noninvasive Method of Rejection Diagnosis

The recording of electric tissue impedance reflects membrane function and changes of volume and electrolytes in intra-and extra-cellular space. The purpose of this study was to determine if acute cardiac allograft rejection can be diagnosed from alteration of electric transmyocardial impedance (ETMI). Nine Beagle dogs received a heterotopic neck heart transplant. The animals were immunosuppressed with cyclosporine and steroids for the first three postoperative days. ETMI was recorded twice daily. Transcutaneous biopsies were performed whenever the impedance varied by more than 10%. All hearts showed a uniform impedance decrease immediately after transplantation, reaching a stable plateau after three days. A subsequent increase of impedance by 12.4 +/-2.9% was accompanied by a histological diagnosis of mild rejection. A further increase of 23.2 +/-2.6% histologically showed acute moderate rejection. After treatment with steroids the impedance reached the basic plateau again. Compared with the biopsy the sensitivity and specificity were 100%. The results indicate that the inflammatory process of cardiac allograft rejection can be detected with this method. This technique will be clinically applicable when an implantable telemetric device for recording the impedance and its transmission will be developed

Predictors of preoperative depressive risk in patients undergoing coronary artery bypass graft surgery

Dunkel A, Kendel F, Lehmkuhl E, et al. Predictors of preoperative depressive risk in patients undergoing coronary artery bypass graft surgery. Clinical Research in Cardiology. 2009;98(10):643-650

Upscaling in socio-environmental systems modelling: Current challenges, promising strategies and insights from ecology

Sustainability challenges in socio-environmental systems (SES) are inherently multiscale, with global-level changes emerging from socio-environmental processes that operate across different spatial, temporal, and organisational scales. Models of SES therefore need to incorporate multiple scales, which requires sound methodologies for transferring information between scales. Due to the increasing global connectivity of SES, upscaling – increasing the extent or decreasing the resolution of a modelling study – is becoming progressively more important. However, upscaling in SES models has received less attention than in other fields (e.g., ecology or hydrology) and therefore remains a pressing challenge. To advance the understanding of upscaling in SES, we take three steps. First, we review existing upscaling approaches in SES as well as other disciplines. Second, we identify four main challenges that are particularly relevant to upscaling in SES: 1) heterogeneity, 2) interactions, 3) learning and adaptation, and 4) emergent phenomena. Third, we present an approach that facilitates the transfer of existing upscaling methods to SES, using two good practice examples from ecology. To describe and compare these methods, we propose a scheme of five general upscaling strategies. This scheme builds upon and unifies existing schemes and provides a standardised way to classify and represent existing as well as new upscaling methods. We demonstrate how the scheme can help to transparently present upscaling methods and uncover scaling assumptions, as well as to identify limits for the transfer of upscaling methods. We finish by pointing out research avenues on upscaling in SES to address the identified upscaling challenges