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Analysis of vibrational spectra of selected environmental contaminants
Valášková, Martina ; Profant, Václav (advisor) ; Procházka, Marek (referee)
This bachelor thesis deals with the study of the vibrational spectra of melamine and thiram molecules using methods of Raman spectroscopy. Quantum chemical simulations are then used for a detailed interpretation of the measured spectra. Melamine is used as an industrial chemical in plastics and adhesives. However, its ingestion can lead to urinary bladder or kidney stones and, in extreme cases, cause death. Thiram is used as a fungicide and animal repellent, but it is toxic. The investigations included the variability of the Raman spectra of both contaminants in the polycrystalline and liquid phase and the spectra obtained by using the drop coating deposition Raman spectroscopy at different concentrations. 1
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Evaporation of simple and complex fluids at different surface wettability
Májek, Juraj ; Ryabov, Artem (advisor) ; Procházka, Marek (referee)
In this work, we investigate the evaporation dynamics of sessile droplets in two scenarios: (i) droplets evaporating on Teflon plasma polymer coated sur- faces, exhibiting anomalously long evaporation lifetime for their size, (ii) drying droplets with liposome suspensions that gradually spread while evaporating. (i) By observing water droplets evaporating on a silicon wafer coated with a Teflon thin film, we discover that the water disintegrates and penetrates the Teflon film. The droplets hide some of their volume underneath, which then does not evaporate. This leads to anomalously long evaporation times. We attribute this effect to structural instability of the Teflon layer, stemming from the contact of non-polar Teflon and polar SiO2. By using Teflon surfaces at most week old, this effect can be prevented. We further identify and describe typical features of the penetration, allowing for its early detection. (ii) We measure the spreading of liposome-laden droplets and find an increase of radius up to 30% of the initial value. During the increase, the droplet contact line spreads in bursts, or protrusions, not uniformly. Existing literature shows that liposomes adsorb on both the air/water and the water/surface interface and reduce the corresponding surface tensions γgl and γsl. We find that when the...
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HDO Raman spectrum
Šubr, Martin ; Štěpánek, Josef (advisor) ; Procházka, Marek (referee)
Title: HDO Raman spectrum Author: Martin Šubr Department: Institute of Physics of Charles University Supervisor: Prof. RNDr. Josef Štěpánek, CSc., Institute of Physics of Charles University Abstract: The main aim of this thesis is to determine the HDO Raman spectrum. This spectrum cannot be measured separately in its liquid form, but it is possible to obtain it by a specific mathematical processing of sets of measured spectra with different H/D ratios. In this work we measured Raman spectra of liquid water with different mole fractions of water and heavy water, which were evaluated by factor analysis. Except for well-known spectra of water and heavy water, spectrum of HDO was determined. For fitting of this spectrum and its analysis, model with equilibrium constant and linear correction of the spectral shape with respect to the relative ratio of D was used. Keywords: Raman scattering, water and heavy water, HDO, factor analysis
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Surface-enhanced Raman spectral detection of bilirubin and temporally synchronized monitoring of its photochemical transformations in selected solvents by SERS and electronic absorption spectroscopy
Hrnčířová, Jana ; Vlčková, Blanka (advisor) ; Procházka, Marek (referee)
Surface-enhanced Raman scattering (SERS)-active systems based on macroscopic Ag nanosponge aggregates as well as the conditions of SERS spectral measurements were optimized for selective and sensitive detection of a biomedically important, amphiphilic bile pigment bilirubin (BR) in alkaline aqueous solutions and in its solutions in a selected water miscible solvent, namely dimethylsulfoxide (DMSO) and/or water-immiscible solvent, namely CH2Cl2. Ag nanosponges assembled by using HCl as a pre-aggregation agent were found to be the optimal SERS-active systems for a reliable detection of BR in all the above-mentioned solvents. In all cases, the protonated form of adsorbed BR has been detected upon BR incorporation into Ag nanosponges, and its marker bands have been established by SERS spectral probing at excitation wavelengths in the 445-780 nm range. The sensitivity of SERS spectral detection was evaluated in terms of the concentration values of SERS spectral detection limits (SERS LODs) of BR incorporated into Ag nanosponges. In particular, the SERS LOD for BR incorporated from its alkaline aqueous solution is 1 x 10-8 M (at 532 nm excitation), for BR incorporated from its solution in DMSO, its value is also 1 x 10-8 M (at 532 and/or 633 nm excitations), and for incorporation from the solution of BR...
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Functional biomolecular coatings for affinity biosensors for medical diagnostics
Hemmerová, Erika ; Homola, Jiří (advisor) ; Procházka, Marek (referee) ; Skládal, Petr (referee)
OF THE DOCTORAL THESIS Title: Functional biomolecular coatings for affinity biosensors for medical diagnostics Author: Erika Hemmerová Department: Institute of Photonics and Electronics of the Czech Academy of Sciences Chaberská 1014/57, 182 51 Prague, Czech Republic Supervisor: Prof. Ing. Jiří Homola, CSc., DSc. Institute of Photonics and Electronics of the Czech Academy of Sciences Chaberská 1014/57, 182 51 Prague, Czech Republic Abstract: Detection and identification of diseases in their early stages represents one of the major goals of the contemporary medical diagnostics. This need drives a research of biomolecular processes behind the particular diseases and development of analytical devices for routine and long-term monitoring of the individuals' health. Surface plasmon resonance biosensors (SPR) have potential to contribute to addressing both of these challenges. This work aims at advancing multiple aspects of SPR biosensor method. It involves study and optimization of selected functional biomolecular coatings in order to improve the performance characteristics of SPR biosensors. It demonstrates utilization of these coatings in novel detection platforms for sensitive monitoring of multiple analytes, and in research of selected biomolecular interactions related to Alzheimer's disease. The...
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Surface-enhanced resonance Raman scattering of Zn(II) porphyrins in systems with aggregated and non-aggregated Ag nanoparticles
Spáčil, Dušan ; Vlčková, Blanka (advisor) ; Procházka, Marek (referee)
In this diploma thesis, SERRS(Surface - enhanced resonance Raman Scattering) and SERS (Surface - enhanced Raman Scattering), surface of plasmon extinction spectra and TEM images of systems with tetracationic zinc porphyrin ZnTMPyP and silver nanoparticles (Ag NPs) were studied and interpreted. The systems with isolated nanoparticles and the systems with compact aggregates were investigated. The systems with isolated nanoparticles were prepared by addition of ZnTMPyP to hydrosol of Ag NPs. NaCl was added to this system and so compact aggregates were prepared. SERRS and SERS spectra of ZnTMPyP were studied at excitation wavelengths λexc= 441.6 nm a 532 nm. Firstly, stationary systems and secondly dynamic development of hydrosol Ag NPs → Ag NPs/ ZnTMPyP → Ag NPs/ ZnTMPyP/ NaCl systems for 680 s was investigated. Time evolution of SERRS and SERS spectra were analyzed by factor analysis (FA) and time evolution of spectra extinction plasmon were measured. FA showed a strong increase of the signal of ZnTMPyP after the addition of NaCl, i.e. after conversion of isolated nanoparticles to compact aggregates. In these systems with high concentration of ZnTMPyP the increase of signal was succeeded by its decreased. With help of FA the limit of SERRS spectral detection (λexc= 441,6 nm) and limit of SERS spectral...
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Preparation and testing of silver immobilized nanoparticles for SERS spectroscopy of biomolecules
Molnár, Peter ; Procházka, Marek (advisor) ; Šmejkal, Petr (referee)
Main goal of this work was to develop methodology of immobilization of silver nanoparticles to silanized glass plates and employment of these substrates in biomolecular study using surface-enhanced Raman scattering (SERS). The suitable substrates for SERS spectroscopy, borohydride-reduced colloidal nanoparticles immobilized by mercapto- or aminosilane, have been found. Good SERS spectra of positively charged TMPyP porphyrin as well as of water insoluble TPP porphyrin (without interference of the solvent) have been obtained. Our results clearly show, that our substrates provide unique possibility how to measure SERS spectra of the porphyrins in his native free-base form (what is impossible directly from the colloid). Further experiments confirm that the porphyrins are protected against metalation due to the presence of the silane employed for the silver particles immobilization.
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