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Preparation and Characterization of Magnetic Carriers from Hypercrosslinked Polystyrene Microspheres and their Application in a Biosensor.
Šálek, Petr ; Šňupárek, Jaromír (referee) ; Šafařík,, Ivo (referee) ; Horák, Daniel (advisor)
With the aim to develop and characterize a functionalized highly magnetic polymer carrier of micrometer size and of a narrow particle size distribution that will be suitable for biological application, hypercrosslinked microspheres were prepared. Simultaneously, the relation between structure and properties of product was observed. Condition of dispersion polymerization were optimized to obtain starting monodisperse poly(styrene-co-divinylbenzene) [P(St-DVB)] microspheres. The P(St-DVB) microspheres of different degree of crosslinking were prepared and effect of some polymerization parameters such as type of solvent, initiator, concentration and mode of DVB addition on morphology, size and particle size distribution were investigated. The starting microspheres were hypercrosslinked to obtain microporous inner structure. Hyperosslinked particles had very large specific surface area (> 1000 m2/g) and a high content of micropores (ca. 0.6 ml/g). First, P(St-DVB) microspheres were chloromethylated using three different chloromethylation agents to regulate their porous properties. Hypercrosslinking was achieved by the addition of stannic chloride as a catalyst and by increasing a temperature. The hypercrosslinked microspheres were then functionalized with sulfo- or aminogroups. The functional groups captured precipitated iron oxide inside the porous structure of the microspheres and also served as a reactive site for intended immobilization of the protein. A solution of ferrous and ferric chloride was imbibed under vacuum into the porous structure and the iron oxide was precipitated by an aqueous ammonia solution. Finally, the magnetic functionalized hypercrosslinked micropsheres were integrated into a biosensor for qualitative detection of ovalbumin.
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Nanofiber membranes generating singlet oxygen with magnetic separation
Liška, Vojtěch ; Mosinger, Jiří (advisor) ; Kubíček, Vojtěch (referee)
This thesis focuses on the preparation and study of a new type of photoactive polyurethane nanofiber membrane with encapsulated 5,10,15,20-meso-tetraphenylporphyrin (TPP) photosensitizer and maghemite nanoparticles. The membrane was prepared by electrospinning and shows effective photogeneration of O2 (1 Δg) and photoantibacterial effect on the surface. The membrane can be easily separated by a magnetic field. The magnetic behaviour of the maghemite nanoparticles was studied using Mössbauer spectroscopy. Their size was estimated by DLS. The final nanofiber membrane was characterized by UV-VIS, emission spectroscopy, and by electronic microscopy (SEM). The kinetics of O2 (1 Δg) generation was studied by time-resolved spectroscopy and the relative efficiency of photooxidation was studied using external acceptor of O2 (1 Δg). Significant photoantibacterial properties against bacteria strain Escherichia coli were detected on the surface of the membrane functionalized with TPP photosensitizer.
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The calculation of magnetic field distribution in nonlinear anisotropic media using the finite element method
Kunický, Zdeněk
Title: The calculation of magnetic field distribution in nonlinear anisotropic media Author: Zdeněk Kunický Department: Department of Numerical Mathematics, Faculty of Mathematics and Physics, Charles University in Prague Supervisor: RNDr. Tomáš Vejchodský, Ph.D., Mathematical Institute of the Academy of Sciences of the Czech Republic Supervisor's e-mail address: vejchod@math.cas.cz Abstract: In the present work we study the modelling of stationary magnetic fields in nonlinear anisotropic media by FEM. The magnetic characteristics of such materials are thouroughly examined and eventually applied to the construction of a full 2D model of an anisotropic steel sheet. Some improvements in the construction in comparision with the ones previously published were achieved. We point out that the standard formulations and the subsequent theorems for the boundary value problems do not in fact correspond with the physical situation. Instead, we propose new formulations that reflect real physical properties of matter. General existence and uniqueness theorems for the obtained boundary value problems are proved as well as the convergence theo- rems for the discrete solutions. The conventional and full 2D model of an anisotropic steel sheet are compared in two transformer core models using the adaptive Newton- Raphson...
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Nanofiber membranes generating singlet oxygen with magnetic separation
Liška, Vojtěch ; Mosinger, Jiří (advisor) ; Kubíček, Vojtěch (referee)
This thesis focuses on the preparation and study of a new type of photoactive polyurethane nanofiber membrane with encapsulated 5,10,15,20-meso-tetraphenylporphyrin (TPP) photosensitizer and maghemite nanoparticles. The membrane was prepared by electrospinning and shows effective photogeneration of O2 (1 Δg) and photoantibacterial effect on the surface. The membrane can be easily separated by a magnetic field. The magnetic behaviour of the maghemite nanoparticles was studied using Mössbauer spectroscopy. Their size was estimated by DLS. The final nanofiber membrane was characterized by UV-VIS, emission spectroscopy, and by electronic microscopy (SEM). The kinetics of O2 (1 Δg) generation was studied by time-resolved spectroscopy and the relative efficiency of photooxidation was studied using external acceptor of O2 (1 Δg). Significant photoantibacterial properties against bacteria strain Escherichia coli were detected on the surface of the membrane functionalized with TPP photosensitizer.
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The calculation of magnetic field distribution in nonlinear anisotropic media using the finite element method
Kunický, Zdeněk
Title: The calculation of magnetic field distribution in nonlinear anisotropic media Author: Zdeněk Kunický Department: Department of Numerical Mathematics, Faculty of Mathematics and Physics, Charles University in Prague Supervisor: RNDr. Tomáš Vejchodský, Ph.D., Mathematical Institute of the Academy of Sciences of the Czech Republic Supervisor's e-mail address: vejchod@math.cas.cz Abstract: In the present work we study the modelling of stationary magnetic fields in nonlinear anisotropic media by FEM. The magnetic characteristics of such materials are thouroughly examined and eventually applied to the construction of a full 2D model of an anisotropic steel sheet. Some improvements in the construction in comparision with the ones previously published were achieved. We point out that the standard formulations and the subsequent theorems for the boundary value problems do not in fact correspond with the physical situation. Instead, we propose new formulations that reflect real physical properties of matter. General existence and uniqueness theorems for the obtained boundary value problems are proved as well as the convergence theo- rems for the discrete solutions. The conventional and full 2D model of an anisotropic steel sheet are compared in two transformer core models using the adaptive Newton- Raphson...
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Preparation and Characterization of Magnetic Carriers from Hypercrosslinked Polystyrene Microspheres and their Application in a Biosensor.
Šálek, Petr ; Šňupárek, Jaromír (referee) ; Šafařík,, Ivo (referee) ; Horák, Daniel (advisor)
With the aim to develop and characterize a functionalized highly magnetic polymer carrier of micrometer size and of a narrow particle size distribution that will be suitable for biological application, hypercrosslinked microspheres were prepared. Simultaneously, the relation between structure and properties of product was observed. Condition of dispersion polymerization were optimized to obtain starting monodisperse poly(styrene-co-divinylbenzene) [P(St-DVB)] microspheres. The P(St-DVB) microspheres of different degree of crosslinking were prepared and effect of some polymerization parameters such as type of solvent, initiator, concentration and mode of DVB addition on morphology, size and particle size distribution were investigated. The starting microspheres were hypercrosslinked to obtain microporous inner structure. Hyperosslinked particles had very large specific surface area (> 1000 m2/g) and a high content of micropores (ca. 0.6 ml/g). First, P(St-DVB) microspheres were chloromethylated using three different chloromethylation agents to regulate their porous properties. Hypercrosslinking was achieved by the addition of stannic chloride as a catalyst and by increasing a temperature. The hypercrosslinked microspheres were then functionalized with sulfo- or aminogroups. The functional groups captured precipitated iron oxide inside the porous structure of the microspheres and also served as a reactive site for intended immobilization of the protein. A solution of ferrous and ferric chloride was imbibed under vacuum into the porous structure and the iron oxide was precipitated by an aqueous ammonia solution. Finally, the magnetic functionalized hypercrosslinked micropsheres were integrated into a biosensor for qualitative detection of ovalbumin.
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