National Repository of Grey Literature 381 records found  1 - 10nextend  jump to record: Search took 0.05 seconds. 
Preparation of nanoparticles and nanofibers for application in anti-acne products
Tilšarová, Kamila ; Veselá, Mária (referee) ; Skoumalová, Petra (advisor)
The diploma thesis was focused on the preparation and characterization of nanoparticles and nanofibres with active substances from chosen herbs with the aim to apply this materials to the products against acne. Various types of extracts were tested on the content of polyphenols, flavonoids and antioxidation activity. These extracts were encapsulated to the liposomes and fibres of polyhydroxybutyrate. Prepared liposomes and fibres were tested mainly on antioxidation activity and antimicrobial activity against the strain Propionibacterium acnes. Then, liposomes were applied to cosmetic emulsions. These creams reported high antioxidation activity and excellent stability determined by analytical centrifugation. Prepared nanofibres also reported high antioxidation activity and antimicrobial effect as well. Finally, particles and fibres were tested in contact with human cells. In appropriate concentration, there was no cytotoxic effect and tested materials can be used in applications on problems with acne.
Influence of nanoparticles on the properties of electroinsulation varnish
Michlíček, Petr ; Havlíček, Svatopluk (referee) ; Polsterová, Helena (advisor)
This work deals with issues of dielectric composite materials. The general aim is to observe how the amout of nanofilling influence dielectric spectrum in dependence on relative humidity and temperature which is measured on prepared samples. For this purpose had been created variety of a samples of electroinsulating varnish with different percentage of filling with nanoparticles. Experimental material is epoxy resin NH91 LV filled by Al2O3 nanoparticles.
Study of organs of mice in inhalation experiments
Vrlíková, Lucie ; Diviš, Pavel (referee) ; Dočekal, Bohumil (advisor)
The diploma thesis is devoted to study potential risks for living organisms resulting from inhalation of nanoparticles of chosen heavy metals. The main aim of this work is the investigation of organs from experimental white mice after their guided inhalation of lead nanoparticles. The samples of liver and lungs from these animals are taken in time periods during the inhalation experiments and processed by specific methods for their evaluation. After pressurized microwave assisted decomposition of selected samples of mice organs in high purity concentrated nitric acid the content of lead is determined by atomic absorption spectrometry with electrothermal atomization. Furthermore, the changes are monitored using the microscopy of histological slides stained with hematoxylin-eosin. The results of both approaches are evaluated and compared within the frame of this work.
Nanoparticles of platinum metals in the environment
Berka, Michal ; Kučerík, Jiří (referee) ; Komendová, Renata (advisor)
Platinum nanoparticles, mainly released from automotive catalysts, pose a potential risk to the environment. The aim of this bachelor thesis is to investigate the effect of platinum nanoparticles on soil properties at different humidities. Specifically, how nanoparticles affect the stability of hydrogen bridges, the stability of aliphatic crystals, and water retention in soil. For the analysis of relations between platinum nanoparticles, water and soil, a method of thermal analysis was used, namely differential scanning calorimetry. The theoretical part is devoted to the general introduction to platinum metals and nanoparticles. And the preparation of nanoparticles, their characterization and their properties. The result of the experiments is that platinum nanoparticles affect the soil properties relatively significantly.
The development of ultra-high strength (UHPC) and reactive powder (RPC) composites
Rundt, Lukáš ; Hela,, Vlastimil (referee) ; Hela, Rudolf (advisor)
Bachelor’s thesis studies ultra-high strength concrete and reactive powder composites. In theoretical part there are researched and described properties of raw materials used for their production, mainly additions. Design methodology, processing and types of curing are also studied. Psychical mechanic and durability properties of fresh and hardened concrete are described. In practical part 4 mixtures were designed and prepared and their rheological properties, strengths after 7 and 90 days in case of UHPC and strengths after 7, 28 and 60 days in case of RPC were tested.
Analysis of biological significant substances
Maděránková, Denisa ; Rychtárik, Milan (referee) ; Roleček, Jiří (advisor)
Selected methods of Raman spectroscopy, like surface-enhanced Raman spectroscopy and single molecule Raman spectroscopy, are described in this diploma work. The basis of two methods for numerical modelling of optical properties of micro- and nanoparticles are prefaced. The methods are Discrete Dipole Approximation and Finite Difference Time Domain. Micro- and nanoparticles are used in surface enhanced Raman spectroscopy and other nanospectroscopic methods. Further, the main instrumentation needed for Raman spectroscopy is described. The first part of experimental section of this work is numerical modelling of photonic nanojet that occures behind dielectric microparticles. This phenomenon leads to a new technique of confocal microscopy with Raman spectra measuring. The second experimental section contains results of Raman spectra measurement with beta-carotene and surface-enhanced Raman spectra of beta-carotene in silver-sol solution.
Influence of PbO and CdO nanoparticles on particular physiological functions in mouse.
Svozilová, Eva ; Vrlíková, Lucie (referee) ; Večeřa, Zbyněk (advisor)
The aim of this bachelor´s thesis is to assess the long-term effects of inhalation of nanoparticles of lead oxide and cadmium oxide on the weight of selected organs of experimental white mice. The selected organs (spleen, liver, kidney, lungs, brain) were successively collected during a period of thirteen weeks. The effect of inhalation of both metal oxides was statistically evaluated. In both study groups of the experiment (PbO and CdO), the relation between organs weight and the length of inhalation and the relation between organs weight and inhalation of differing metal concentrations were evaluated, and results both of the study groups were compared to each other.
Surface Plasmon Resonances on Colloidal Nanoparticles
Beránek, Jiří ; Brzobohatý,, Oto (referee) ; Šikola, Tomáš (advisor)
The presented diploma thesis is focused on the Localized Surface Plasmons (LSP). The far-field optical response of the colloidal solutions of gold nanoparticles caused by LSP was investigated and compared with the numerical calculations. For the simulations, the Discrete Dipole Approximation (DDA) and Finite-Difference Time Domain (FDTD) techniques were employed. In particular, the shape and size effects of spherical particles and nanorods were studied. The simulations performed by both methods are in a good agreement for the spheres. For the nanorods, the resonance was found to be affected markedly by their geometry. Also, broader resonance peaks were found. This effect was assigned to the sample size distribution and its influence is discussed by comparing the simulations with experiments. In addition, synthesis of nanorods was carried out as well. Finally, the results on the study of optical properties of silver clusters formed under equilibrium conditions are presented.
Electrochemical Characterization of Nanostructured Surfaces Modified by Substancies with Thiol Bound
Urbánková, Kateřina ; Kynclová, Hana (referee) ; Hrdý, Radim (advisor)
This master thesis deals with nanotechnology, nanoparticles and nanostructured surfaces, electrochemical methods, especially voltammetry, cyclic voltammetry, electrochemical impedance spectroscopy and contact angle measurement. One part is focused on electrodes primarily nanostructured and modified by substancies with thiol bound. Tutorial for preparation of gold nanostructured electrods is introduced in practical section including SEM photos of electrode surface. Nanostructured and bare gold electrodes were modified by 11-mercaptoundecanoic acid, streptavidin, glycine and biotin and measured by cyclic voltammetry, electrochemical impedance spectroscopy and contact angle.
Study of the influence of nanoparticles on water properties
Šram, Matěj ; Komendová, Renata (referee) ; Řezáčová, Veronika (advisor)
This work deals with the study of the influence of platinum nanoparticles with a size of 3 nm on the properties of water in a porous system. SiO2 with a defined pore size was used as a porous system, which can simulate the mineral component of the soil. The theoretical part deals with the properties of free and porous water and the impact of nanoparticles on the environment. In the experimental part, the properties of free water, water in the porous system and the influence of the presence of platinum nanoparticles on these systems are investigated using differential scanning calorimetry (DSC). The observed processes were melting, solidification and evaporation, and derived quantities such as crystallization and melting point.

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