| |
|
The study of photodynamic phenomenon on melanom cell lines
KOLÁČKOVÁ, Zdeňka
Photodynamic therapy (PDT) is a medical method combining the use of photodynamic active substance and light in presence of oxygen. It extends the treatment possibilities of tumor and non-tumor disorders. It complements surgical treatment, radiotherapy, chemotherapy and immunotherapy. An increased accumulation of photosensitive substance in pathological focus is the base of PDT. Subsequent irradiation by light of suitable wavelenght evokes photodynamic reactions leading to formation of reactive oxygen species and to biological answer leading to tumor cells damage. The final effect depends on sensitizer type, its concentration in target tissue and on used source of radiation. Aim of the thesis is to prove photodynamic properties of newly developed photodynamic active substance phtalocyanin CIAIPcS2 and possibilities of its usage to induce photodynamic phenomenon in melanom cells. Owing to absorption of light in sensitizer the formation of excited states happens, and then the excited form of sensitizer reacts directly with substrate. During this reaction free radicals of substrate form or transfer of energy from sentitizer to oxygen and formation of highly reactive singlet oxygen happen. Free radicals, especially radicals of lipid components of cell membranes, are the major cause of tumor destruction. Fruitfulness of PDT depends not only on type of sensitizer and level of oxygen in tumor cell but also on used light source. Luminiscence diodes (LEDs) were used as the source of light. Formation of ROS after PDT was detected with the help of fluorescent molecular probe CM-H2DCFDA on spectrofluorimeter Synergy HT and on fluorescent microscope Olympus IX 81 with image analysis. According to our results the production of ROS depends on concentration of sensitizer CIAIPcS2 and the radiation dose. We proved that the sensitizer CIAIPcS2 is suitable photodynamic active substance and evokes photodynamic phenomenon in tumor cells.
|
|
Investigation of parameters of ultrafast laser pulses
Chlouba, Tomáš ; Němec, Petr (advisor) ; Preclíková, Jana (referee)
In this work we investigate parameters of laser radiation coming from continual titan-sapphire laser 3900S, pulsed titan-sapphire laser Mai-Tai HP and from optical parametric oscillator Inspire made by Spectra Physics. We are particulary insterested in dependence of power, width of the beam, noise and beam pointing stability as a function of wavelength. We have also measured beam pointing stability in time and compared it with beam stability during change of wavelength. With pulse laser we are also interested in the spectra and time width of the pulses. We aim to compare the properties of both titan-sapphire lasers and to verify specifications of Mai-Tai and Inspire given by the manufacturer.
|
| |
|
Low temperature STM study of metal adsorption on Si(100)2×1
Majer, Karel ; Ošťádal, Ivan (advisor) ; Kocán, Pavel (referee)
The thesis covers the preparation of a UHV system enabling low-temperature measurements by scanning tunneling microscope and the study of one-dimensional aluminium structures on the Si(100)2 × 1 surface. Calibration measurements of deposition rate of Al from an evaporator, temperature of the silicon substrate during annealing and temperature of a cooling device during cooling have been carried out. A STM measurement has been carried out at the temperature of 60řC and aluminium chains on the silicon surface have been observed. Their lengths and forms have been analyzed and length distributions at various tem- perature have been created by using previously obtained data. The observed distributions have been discussed concerning the underlying physical processes. 1
|
|
STM/STS study of bimetallic nanostructures on silicon surfaces
Zimmermann, Petr ; Mysliveček, Josef (referee) ; Sobotík, Pavel (advisor)
In this study we examine linear nanostructures consisting of metals of III. (Al, In) and IV. (Sn) group on the Si(001)2×1 surface by means of scanning tunnelling microscopy & spectroscopy. Atoms on the surface align into atomic chains growing perpendicularly to the dimer rows of the surface reconstruction. The chain structure consists of dimers that adsorb in the troughs between the dimer rows of the surface reconstruction. We observe that the chains consist of sequences of homodimers of either elements combining with heterodimers. The InSn chain structure is analysed with regard to theoretical ab-initio calculations of the chain dimer structure. The model is then applied to the Al-Sn system. We observe that the Al-Sn chains tend to consist of aligned heterodimers. The appearance of heterodimers in STM depends on the chemical composition of the neighbouring dimers. We can also observe the tendency of chains to agglomerate and via Sn atoms create quasi periodic 2D structures. The electronic structure of an Al, Sn and mixed AlSn dimer is studied by means of tunnelling spectroscopy. Despite its small, nonzero density of states on the Fermi energy, the character of the mixed dimer appears to be rather non-conductive.
|
|
Investigation of Polyelectrolytes Interactions with Cationic Aminogroups-containing Amphiphiles
Zeman, Jan ; Běťák, Jiří (referee) ; Chytil, Martin (advisor)
The study deals with interactions of polyelectrolytes polystyrene sulfonate and hyaluronic acid with nitrogenic amphiphilic substances, represented by lysine and albumine. To study the interactions pH-metry, conductance, viscositic and turbidity measurement, DLS and reometry were used. All mixtures of different concentrations were measured and the data were compered with data obtained from measurement of samples with amphiphilic sumstances without polyelectrolytes. Observed interactions occured in the aminoacid concentrations between 0 to 20 mmoldm-3, then the PSS interaction groups were fully bonded by lysine and no more interactions were recognized. The same behaviour were observed in albumine solutions with concentration under 2 gdm-3.
|
|
The application of electrochemical impedance spectroscopy for investigation of enzyme kinetics
Pospíšilová, Michaela ; Sedláček, Jiří (referee) ; Fohlerová, Zdenka (advisor)
The application of electrochemical impedance spectroscopy (EIS) in theory and experiment for investigation of redox enzyme kinetics has been already described. The impedance studies are quite sensitive to the changes at the interface caused by adsorption of charged species and therefore can be used to study the kinetics of adsorption of macromolecules and also enables us to study enzyme kinetics since the action of the enzymes on their substrates involved modification and generation of charged species. In this work, we would explore the potential of electrochemical impedance technique to follow the kinetics of glucose oxidasesubstrate reactions on the immobilized surface. The enzyme will be allowed to interact with different concentrations of its substrate and the resulting reaction will be recorded in real time. Changes in the imaginary component of the impedance at various substrate concentrations will be expected to follow MichelisMenten kinetics. The experimental procedure should be simple and can be carried out directly in buffer solutions most suited for the required interaction to take place, without the requirement of any additional redox probes.
|
|
The study of spin-lattice and spin-spin NMR relaxation of 1H nuclei in water
Dvořák, Petr ; Englich, Jiří (advisor) ; Lang, Jan (referee)
The dependences of spin-lattice and spin-spin relaxation rates of 1H nuclei on the concentration of H2O in H2O-D2O mixtures were measured using experimental methods of high resolution NMR. Before this measurement, we investigated the influence of radiation damping, paramagnetic impurities and temperature upon measurement of relaxation rates, as well as methods of its reduction. We also measured the dependences of spin-lattice and spin-spin relaxation rates of 17O nuclei on the concentration of H2O in H2O-D2O mixtures. We discuss the results, aiming to verify the accurancy of prior interpretations and to assess the influence of chemical exchange.
|
|
Rheological study of high-molecular weight hyaluronan-protonated aminoacids interactions
Zeman, Jan ; Běťák, Jiří (referee) ; Chytil, Martin (advisor)
The study deals with interactions of hyaluronic acid with protonized amino acids Lysin and 6-aminocaproic acid. To study the interactions pH-metry, conductance measurement and reometry were used. The mixtures of hyaluronan and the aminoacids of different concentrations were measured and the data were compered with data obtained from measurement of amino acid samples in pure water. Observed interactions occured in the aminoacids concentrations between 0 to 10 mmolxdm3, then the HyA carboxylic groups were fully bonded by amino acids and no more interactions were recognized.
|
guest ::
