The presented thesis is a continuation of the bachelor work, in which the effects of monovalent ions on neutral model lipid membranes were characterized. Herein physical properties of physiologically relevant anionic membranes in the presence of monovalent cations and oxidized lipids were studied. Hydration and mobility of the lipid bilayer at glycerol level were investigated using fluorescent solvent relaxation technique. In the first part of this work the interactions of cations (Na+ , K+ , Cs+ ) with negatively charged POPC/POPS lipid mixture, which is a good model of inner leaflet of cellular membrane, were studied. The presence of cations resulted in dehydration and substantial hinderence of mobility of hydrated lipids at the glycerol level probed by Laurdan. Clear specificity of those effects, which correlated with Hofmeister series have been observed. In the second part of the work truncated oxidized phospholipids, oxPLs (PazePC, PoxnoPC, PGPC, POVPC), which are known to be important in pathophysiology of numerous diseases, were investigated. 10 mol% of each oxPL was incorporated into neutral and anionic lipid bilayers, the hydration and mobility of which were measured in water or in KCl solution. The results reveal complex interactions between oxPLs, negatively charged lipids, and K+ . In...

Luminescence sensors based on LED were prepared by modification of LED poly- carbonate surface and following binding of luminescence dyes on this surface. Two methods of modification were utilized. The first one was the oxidation of the surface yielding free carboxylic groups. Such modified LEDs were then covered by cationic cresyl violet dye. The second modification consisted of nitration and consequent reduction to free amino groups followed by binding of anionic sulforhodamine dye. The stability of emission and the stability of dye binding were studied. Then, the response of constructed sensors to toluene as analyte in gas and liquid phase was measured.

This thesis deals with the further development of the technique of generation of volatile compounds as derivatization methods by speciation analysis of selenium compounds. Specifically, this diploma thesis compares technique chemical and electrochemical generation of selected species of selenium (inorganic Se (IV) inorganic Se (VI), selenomethionine (Se- Met), selenocysteine (Se-Cys), methyl-selenocysteine (Met-Se-Cys) and seleno-urea (Se-U)). The achieved basic analytical characteristics are compared of each species in non-column arrangement with atomic fluorescence spectrometry. The effect of pre- reduction/decomposition unit are tested, using the pre-reduction agent KBr and hydrochloric acid at higher temperature and in the presence of UV radiation. Keywords Selenium, speciation analysis, chemical hydride generation, electrochemical hydride generation, atomic fluorescence spectrometry

The complexity of cell membranes is far from being only a simple assembly of lipids and proteins separating cells from the surrounding environment. Each of the thousands of different membrane components performs its specific role in cellular functions, since a multitude of biological processes is mediated by membranes. The understanding of the molecular basis of these processes is one of the important aims of current biological research. Our research employing single- molecule fluorescence methods (e.g. FCS, FCCS, FLIM-FRET) has made a contribution to the knowledge of membrane lateral organization or mechanism of membrane fusion. Furthermore, we revealed the mechanism of membrane activity of a small natural compound. As native cell membranes are very complex structures, we performed the experiments on simplified model lipid membranes that allow studying lipid-lipid or lipid-protein interactions at the molecular level in a controlled way. The first part of this thesis deals with the mode of action of a membrane active secondary metabolite didehydroroflamycoin (DDHR). We demonstrated that DDHR is a pore-forming agent and that this activity is influenced by the presence of cholesterol. Direct visualization of intrinsic fluorescence of DDHR revealed its preferential partitioning into membrane areas...

This Licentiate thesis presents research accomplished at theSection of Atomic and Molecular Physics at the Royal Instituteof Technology in Stockholm using photon induced fluorescencespectroscopy (PIFS) during the last two years. The main results presented are summarized: - Neutral photodissociation in CO was observed aftersynchrotron photon excitation in the range 19-26 eV bycollecting dispersed fluorescence from excited neutral C atoms.Follow-up ab initio calculations point out CO Rydberg seriesconverging to the CO+ C and D states as precursors. - The branching ratio between N2 + (B-X)(v’=1,v’’=2) and (v’=0,v’’=1)transitions in the 20-46 eV energy range reveals strongnon-Franck-Condon effects. Ab initio calculations indicate thatthe autoionization of certain superexcited states areresponsible for some of the structures present in the branchingratio curve, confirming the important role of non-Rydbergdoubly excited resonant states (NRDERS) in de-excitationprocesses above the ionization potential. - Photon induced neutral dissociation processes in NO arereported. Neither Rydberg series nor other molecular states inNO known so far can account for the collected data. From abinitio calculations more information regarding the NO precursorstates and the mechanism behind the observed neutraldissociation were obtained. - The details of a new experimental set-up for gas phasefluorescence measurements using synchrotron radiation aredescribed. It is able to perform simultaneous measurements ofdispersed and total fluorescence in the visible range. Thefirst results obtained with this set-up are presented,concerning fluorescence after excitation of the N2 molecules inthe N 1s edge. These four studies conform the set of papers enclosed in theLicentiate thesis. Finally a pre-study to further apply PIFS to speciespreviously excited by microwave discharge is included as futureplans. / NR 20140805

This thesis describes the design, fabrication, and characterization of the Implantable Fluorescence Imager (IFI): a camera chip with a needle-like form factor designed for imaging neuronal activity in the deep brain. It is fabricated with a complementary metal oxide semiconductor (CMOS) process, allowing for hundreds or thousands of single- photon-sensitive photodetectors to be densely packed onto a device width comparable to a single-channel fiber optic cannula (~100 μm). The IFI uses a combination of spectral and temporal filters as a fluorescence emission filter, and per-pixel Talbot gratings for 3D light-field imaging. The IFI has the potential to overcome the imaging depth limit of multi-photon microscopes imposed by the scattering and absorption of photons in brain tissue, and the resolution limit of noninvasive imaging techniques, such as functional magnetic resonance imaging and photoacoustic imaging. It competes with graded index lens-based miniaturized microscopes in imaging depth, but offers several comparative advantages. First, its cross sectional area is at least an order of magnitude smaller for an equal field of view. Second, the distribution of pixels along its entire length allows the study of multi- layer or multi-region dynamics. Finally, the scalability advantage of silicon integrated circuit technology in system miniaturization and data bandwidth may allow thousands of such imaging shanks to be simultaneously deployed for large-scale volumetric recording.

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This thesis is concerned with the development of a compact, sensitive and reliable instrument for determination of the polarization of fluorescence of fluorescein tagged molecules in solution. The instrument as designed and constructed differs from others (2,3,4,5,6,8,9). The difference is that all of its optical system is aligned on a single axis. This was accomplished by the use of an ellipsoidal mirror positioned between the excitation source and the phototube fluorescence signal receiver. In addition, the excitation source, a 45 watt tungsten-iodide light was electronically regulated to control the intensity. Two types of determinations were made to verify the performance of the instrument. The first was the absolute sensitivity to varying fluorescein concentrations. Concentrations of fluorescein in 0.1 molar sodium phosphate buffer were prepared ranging from 10-6 molar to 10-11 molar. After the minimum detectable concentration was determined, five runs on samples of each concentration from the minimum detectable to 10-6 were made. The second check was for the sensitivity and linearity of the system in the measurement of polarization. Solutions of glycerol ranging from 62% to 90% were prepared with 10-6 molar fluorescein concentration. The data from the fluorescein sensitivity and polarization runs were averaged and the averages plotted on linear paper. In each case the instrument exhibited excellent linear response and reasonable standard deviation.

Laser Induced Fluorescence (LIF) is one of the chief methods for detecting ambient hydroxyl radicals. To measure the absolute concentration of this important atmospheric chemical species, accurately known quenching rate constants due to the dominant gases in the air are of paramount importance. Unfortunately, these rate constants have only been measured under conditions remote from those of ambient air. This dissertation reports the measurement of the rate constants of water, argon, nitrogen and oxygen under ambient conditions. As the LIF is carried out at atmospheric pressure, the OH fluorescence life-time becomes extremely short (about 1 ns). Time Correlated Photon Counting was used to study this short fluorescence phenomenon. The unique feature this study was that the deactivation processes of the excited OH could be described completely by a kinetic model. Detailed theoretical treatments of the LIF processes are presented. The data obtained are consistent with the accepted model, thereby demonstrating the usefulness and validity of the experimental approach. The rate constants (cc molecule('-1) sec('-1)) for quenching by water and argon were accurately measured. The vibrational relaxation rate constant by water (3.4 (+OR-) 0.6 x 10('-10)) is the first value ever reported, while the electronic quenching rate constants for water (k(,Q0) = 7.9 (+OR-) 0.47 x 10('-10), k(,Q1) = 1.48 (+OR-) 0.74 x 10('-10)) are the first measured at atmospheric pressure. The electronic quenching rate constants of the ('2)(SIGMA)(v' = 1) state (k(,Q1)) and the ('2)(SIGMA)(v' = 0) state (k(,Q0)) by argon are k(,Q0) = 0.48 (+OR-) 0.14 x 10('-12) and k(,Q1) = 0.24 (+OR-) 0.06 x 10('-11). The vibrational relaxation rate constant by argon is k(,10) = 0.34 (+OR-) 0.06 x 10('-11). The rate constants for oxygen (k(,Q1) (+OR-) k(,10) = 1.83 (+OR-) 0.43 x 10('-9) and k(,Q0) = 2.6 (+OR-) 0.6 x 10('-10)) are significantly higher than the limited measurements available at low pressure. The rate constants for nitrogen are k(,Q0) = 0.71 (+OR-) 0.08 x 10('-11) and k(,10) = 8.07 (+OR-) 0.65 x 10('-11). All these values are the first obtained at atmospheric pressure and although shown to be consistent with the widely scattered low pressure values, they allow more reliable analysis of ambient OH measurements, and result in a 31.2% increase in the published values.

The objectives of this study were to implement a system to measure mixing in nonreacting flows and to study the mass transfer characteristics of two actively excited turbulent jets. This thesis describes the acquisition and analysis of phase-locked concentration field data using planar Mie scattering from smoke particles and planar laser-induced fluorescence of acetone. Both techniques were shown to be effective in providing information for the actively excited nozzles. However, the laser-induced fluorescence technique was superior for revealing detail in the flowfield structure. Spatial mode control techniques were applied to a triangular nozzle with vibrating actuators as the three sides and a swirl nozzle with pulsating tangential air jets. The effect of the different spatial modes on jet column development and the far fields of both nozzles is presented. Two- and three-dimensional iso-intensity contours, showing the relative intensity of light scattered by the nozzle fluid marker, were generated to show the flow structure. The areas inside the iso-intensity contours in the far field were also measured to determine relative effectiveness of nozzle fluid transport. Large scale structures were visible in the three-dimensional iso-intensity contours from both nozzles. In addition, the transport of seeded nozzle fluid was enhanced by the spatial mode excitation for both nozzles. Spatial mode excitation was also able to affect the shape of the far field contour. In particular, the first counterrotating helical mode, m=±1, generated the greatest effect on nozzle fluid transport and the most pronounced elliptical contour shape in the far field. / Master of Science