Etablierung und Evaluation eines direkten Pankreasfunktionstests am Universitätsklinikum Gießen und Marburg, Standort Marburg, sowie Isolierung von RNA aus dem gewonnenen Pankreassekret

Die in dieser Studie durchgeführte modifizierte Version eines endoskopischen Pankreasfunktionstests konnte am Universitätsklinikum Gießen und Marburg, Standort Marburg, etabliert werden. Der optimale Zeitpunkt der Messung der Lipase-Aktivität konnte festgelegt und der Einfluss der Verdünnung auf die Messung aufgezeigt werden. Die Untersuchung ist gut tolerabel. Um die diagnostische Wertigkeit des in dieser Form angewandten Pankreasfunktionstests zu überprüfen sowie Referenzbereiche festzulegen, muss dieser an Patienten mit nachgewiesener chronischer Pankreatitis durchgeführt werden. Dieser Pankreasfunktionstest kann in Kombination mit anderen bildgebenden Verfahren wie der Endosonographie bei Patienten mit unklaren Bauchschmerzen zum Ausschluss einer chronischen Pankreatitis verwenden werden. Im gewonnenen Pankreassaft konnte RNA isoliert werden. Bei der maschinellen Analyse der RNA-Qualität der gewonnenen Proben zeigte sich eine stark fragmentierte RNA von geringerer Qualität, welche eine sichere PCR-Analyse nur unzureichend zulässt. Ob die festgestellte geringe Qualität der isolierten RNA ausreicht, um die Expression bestimmter Indikatorgene eines Pankreaskarzinoms zu messen, muss in Folgestudien untersucht werden

Hyperspectral remote sensing of cyanobacterial pigments as indicators for cell populations and toxins in eutrophic lakes

The growth of mass populations of toxin-producing cyanobacteria is a serious concern for the ecological status of inland waterbodies and for human and animal health. In this study we examined the performance of four semi-analytical algorithms for the retrieval of chlorophyll a (Chl a) and phycocyanin (C-PC) from data acquired by the Compact Airborne Spectrographic Imager-2 (CASI-2) and the Airborne Imaging Spectrometer for Applications (AISA) Eagle sensor. The retrieval accuracies of the semi-analytical models were compared to those returned by optimally calibrated empirical band-ratio algorithms. The best-performing algorithm for the retrieval of Chl a was an empirical band-ratio model based on a quadratic function of the ratio of re!ectance at 710 and 670 nm (R2=0.832; RMSE=29.8%). However, this model only provided a marginally better retrieval than the best semi-analytical algorithm. The best-performing model for the retrieval of C-PC was a semi-analytical nested band-ratio model (R2=0.984; RMSE=3.98 mg m−3). The concentrations of C-PC retrieved using the semi-analytical model were correlated with cyanobacterial cell numbers (R2=0.380) and the particulate and total (particulate plus dissolved) pools of microcystins (R2=0.858 and 0.896 respectively). Importantly, both the empirical and semi-analytical algorithms were able to retrieve the concentration of C-PC at cyanobacterial cell concentrations below current warning thresholds for cyanobacteria in waterbodies. This demonstrates the potential of remote sensing to contribute to early-warning detection and monitoring of cyanobacterial blooms for human health protection at regional and global scales

Time-domain observation of interlayer exciton formation and thermalization in a MoSe2/WSe2 heterostructure

: Vertical heterostructures of transition metal dichalcogenides (TMDs) host interlayer excitons with electrons and holes residing in different layers. With respect to their intralayer counterparts, interlayer excitons feature longer lifetimes and diffusion lengths, paving the way for room temperature excitonic optoelectronic devices. The interlayer exciton formation process and its underlying physical mechanisms are largely unexplored. Here we use ultrafast transient absorption spectroscopy with a broadband white-light probe to simultaneously resolve interlayer charge transfer and interlayer exciton formation dynamics in a MoSe2/WSe2 heterostructure. We observe an interlayer exciton formation timescale nearly an order of magnitude (~1 ps) longer than the interlayer charge transfer time (~100 fs). Microscopic calculations attribute this relative delay to an interplay of a phonon-assisted interlayer exciton cascade and thermalization, and excitonic wave-function overlap. Our results may explain the efficient photocurrent generation observed in optoelectronic devices based on TMD heterostructures, as the interlayer excitons are able to dissociate during thermalization

Evaluating and Improving the Performance of MPI-Allreduce on QLogic HTX/PCIe InifiniBand HCA

This thesis analysed the QLogic InfiniPath QLE7140 HCA and its onload architecture and compared the results to the Mellanox InfiniHost III Lx HCA which uses an offload architecture. As expected, the QLogic InfiniPath QLE7140 HCA can outperform the Mellanox InfiniHost III Lx HCA in latency and bandwidth terms on our test system in various test scenarios. The benchmarks showed, that sending messages with multiple threads in parallel can increase the bandwidth greatly while bi-directional sends cut the effective bandwidth for one HCA by up to 30%. Different all-reduce algorithms where evaluated and compared with the help of the LogGP model. The comparison showed that new all-reduce algorithms can outperform the ones already implemented in Open MPI for different scenarios. The thesis also demonstrated, that one can implement multicast algorithms for InfiniBand easily by using the RDMA-CM API