Dynamic Modeling and Controller Design of a Novel Marine Energy Converter

Aerospace Engineerin

Accessing Molecular Dynamics in Cells by Fluorescence Correlation Spectroscopy.

Fluorescence correlation spectroscopy (FCS) ana-lyzes spontaneous fluctuations in the fluorescenceemission of small molecular ensembles, thus provid-ing information about a multitude of parameters,such as concentrations, molecular mobility and dy-namics of fluorescently labeled molecules. Per-formed within diffraction-limited confocal volume el-ements, FCS provides an attractive alternative tophotobleaching recovery methods for determining in-tracellular mobility parameters of very low quantitiesof fluorophores. Due to its high sensitivity sufficientfor single molecule detection, the method is subjectto certain artifact hazards that must be carefully con-trolled, such as photobleaching and intramoleculardynamics, which introduce fluorescence flickering.Furthermore, if molecular mobility is to be probed,nonspecific interactions of the labeling dye with cel-lular structures can introduce systematic errors. Incytosolic measurements, lipophilic dyes, such as cer-tain rhodamines that bind to intracellular mem-branes, should be avoided. To study free diffusion,genetically encoded fluorescent labels such as greenfluorescent protein (GFP) or DsRed are preferablesince they are less likely to nonspecifically interactwith cellular substructures

Pollen discrimination and classification by Fourier transform infrared (FT-IR) microspectroscopy and machine learning

The discrimination and classification of allergy-relevant pollen was studied for the first time by mid-infrared Fourier Transform Infrared (FT-IR) microspectroscopy together with unsupervised and supervised multivariate statistical methods. Pollen samples of eleven different taxa were collected, whose outdoor air concentration during the flowering time is typically measured by aerobiological monitoring networks. Unsupervised hierarchical cluster analysis provided valuable information about the reproducibility of FT-IR spectra of the same taxon acquired either from one pollen grain in a 25 m x 25 m area or from a group of grains inside a 100 m x 100 m area. As regards the supervised learning method, best results were achieved using a K nearest neighbors classifier and the leave-one-out cross-validation procedure on the dataset composed of single pollen grain spectra (overall accuracy 84%). FT-IR microspectroscopy is therefore a reliable method for discrimination and classification of allergenic pollen. The limits of its practical application to the monitoring performed in the aerobiological stations were also discussed

Light-induced flickering of DsRed provides evidence for distinct and interconvertible fluorescent states.

Green fluorescent protein (GFP) from jellyfish Aequorea victoria, the powerful genetically encoded tag presently available in a variety of mutants featuring blue to yellow emission, has found a red-emitting counterpart. The recently cloned red fluorescent protein DsRed, isolated from Discosoma corals (), with its emission maximum at 583 nm, appears to be the long awaited tool for multi-color applications in fluorescence-based biological research. Studying the emission dynamics of DsRed by fluorescence correlation spectroscopy (FCS), it can be verified that this protein exhibits strong light-dependent flickering similar to what is observed in several yellow-shifted mutants of GFP. FCS data recorded at different intensities and excitation wavelengths suggest that DsRed appears under equilibrated conditions in at minimum three interconvertible states, apparently fluorescent with different excitation and emission properties. Light absorption induces transitions and/or cycling between these states on time scales of several tens to several hundreds of microseconds, dependent on excitation intensity. With increasing intensity, the emission maximum of the static fluorescence continuously shifts to the red, implying that at least one state emitting at longer wavelength is preferably populated at higher light levels. In close resemblance to GFP, this light-induced dynamic behavior implies that the chromophore is subject to conformational rearrangements upon population of the excited state