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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Komplexy aminoalkylfosfinoxidů / Complexes of aminoalkylphosphineoxides

Mészáros, Bence January 2017 (has links)
Title: Comlpexes of aminoalkylphosphineoxides Author: Bence Mészáros Department: Department of Inorganic Chemistry, Faculty of Science UK Supervisor: doc. RNDr. Vojt ch Kubí ek, Ph.D. Supervisor's e-mail address: kubicek@natur.cuni.cz Three selected aminoalkylphosphine oxides were synthesized: Aminomethyl(diphenyl)phosphine oxide, N-piperidylmethyl(diphenyl)phosphine oxide, N,N-diethylaminomethylbis(hydroxomethyl)phosphine oxide. All prepared substances were characterized by NMR spectroscopy and mass spectrometry. The aminomethyl(diphenyl)phosphine oxide and N-piperidylmethyl(diphenyl)phosphine oxide were obtained in the solid state as single crystals and their structure was determined by X-ray analysis. Acid-base and complexing properties of the studied compounds were studied by potentiometric titration and NMR titration. Protonation constants of all three compounds were obtained, stability constants were not determined because of the low solubility of the complexes in water or low stability of the complexes. The structure of the aminomethyl(diphenyl)phosphine oxide complex with Cu2+ was determined by X-ray analysis. Keywords: complexes, organophosphorus synthesis, phosphine oxides, acid-base and complexation properties
22

Vývoj technik pulsního značení pro studium dynamiky proteinových komplexů. / Development of pulse labelling technology for studying the dynamics of protein complexes.

Fiala, Jan January 2021 (has links)
(IN ENGLISH) Structural mass spectrometry (MS) is an evolving field of structural biology introducing novel techniques for the characterization of biomolecules. Although MS-based techniques only can provide "low-resolution" information compared to standard high-resolution techniques representing by X-ray crystallography, cryo-electron microscopy or nuclear magnetic resonance, its uniqueness lies in the ability to easily obtain structural information about various biomolecules in their native or native-like environment. By employing various approaches, from protein covalent labelling through chemical cross- linking to ion mobility, structural MS provides insight into the structure and dynamics of proteins and their complexes over a broad timescale. This thesis is dedicated to the development of novel structural MS approaches based on pulse covalent labelling and chemical cross-linking. Employing the developed quench-flow microfluidics apparatus, we performed footprinting experiments on proteins and protein complexes in timescale from a few microseconds to single seconds. Specifically, fast photochemical oxidation of proteins (FPOP) and novel fast fluoro alkylation of proteins (FFAP) techniques were utilized to track structural changes of myoglobin upon release of the prosthetic heme group....
23

Stabilita komplexů huminových kyselin s těžkými kovy / Stability of complexes of humic acids with heavy metals

Nováčková, Kristýna January 2011 (has links)
Tato diplomová práce je zaměřena na porovnání termo-oxidační a chemické stability kovových komplexů huminových kyselin. Pro tyto experimenty byly vybrány tři prvky reprezentující skupinu těžkých kovů (kobalt, měď a nikl). Použitá huminová kyselina byla extrahována z Jihomoravského lignitu. Pro přípravu komplexů byly využito různě koncentrovaných roztoků kovů, aby bylo možné pozorovat vliv jejich počáteční koncentrace na obě studované stability připravených komplexů. Chemická stabilita kovových komplexů byla posuzována z hlediska uvolňování kovových iontů ze struktury huminové kyseliny do dvou různých extrakčních činidel (HCl, MgCl2). Termo-oxidační chování bylo zkoumáno pomocí technik termické analýzy: diferenční kompenzační kalorimetrie (DSC) a zejména termogravimetrické analýzy (TGA). Výsledky této práce přinášejí hlubší poznatky o problematice interakce kovů s humifikovanou částí půdní organické hmoty, využitelné k osvětlení problematiky kovových polutantů v životním prostředí a prohloubení žádoucích znalostí procedur jako jsou dekontaminace půdy a remediace.
24

Tolerance poškození DNA novými, biologicky aktivními komplexy platiny / Tolerance of DNA damage by novel biologically active platinum complexes

Vystrčilová, Jana January 2011 (has links)
The anti-tumor activity of platinum based drugs is mediated by their ability to attack DNA. Platinum complexes can alter the structure of DNA by modifying the bases, mainly guanines. The biological consequnces of such interactions are compromising replication and transcription. RNA polymerase complex can stall at a damaged site in DNA and mark the lesion for repair by proteins that are utilized to execute nucleotide excision repair, a pathway commonly associated with the removal of bulky DNA damage from the genome. This RNA polymerase-induced repair pathway is called transcription-coupled nucleotide excision repair. Main goal of this thesis was to study RNA polymerases tolerance of DNA damage by novel, biologically active platinum (II) complexes involving derivatives of aromatic cytokinines as the ligands; cis-[Pt(2-chloro-6-(4-methoxybenzylamino)-9-isopropylpurin)2Cl2](PR-001), cis-[Pt(2-chloro-6-(benzylamino)-9-isopropylpurin)2Cl2](PR-002 )and cis-[Pt(2-(3-hydroxypropylamino)-6-(benzylamino)-9-isopropylpurin)2Cl2](PR-005). DNA templates (constructs) that contain a single, site-specific DNA lesion and support transcription by human RNA polymerase II and bacteriophage T7 RNA polymerase were prepared. The method is making use of polymerase chain reaction (PCR) and biotin-streptavidin interactions and paramagnetic particles to purify the final product. Synthetic oligomers duplexes (75-mer, 56-mer and 15-mer) are ligated to 5´-biotin pCI-neo-G-lessT7 PCR fragment, the 15-mer is either unmodified or modified with a site-specific lesion of PR-005 and cisplatin. We also studied the inhibition of RNA polymerases activity on globally modified plasmid pCI-neo and pUC 19 by novel platinum complexes and cisplatin. We found that bifunctional adducts of complex PR-005 contrary to adducts of PR-001 and PR-002 effectively decrease amount of full lenght transcripts produced by both, human and bacterial RNA polymerases. This result can be explained by a sterical block, induced to DNA by intrastrand cross-link of PR-005 with bulky aromatic ligands.
25

Charakterizace podjednotky SEC15 poutacího komplexu exocyst u A. thaliana / Characterization of the exocyst complex SEC15 subunit in A. thaliana

Aldorfová, Klára January 2016 (has links)
The final step of secretion termed exocytosis is mediated by the exocyst complex. The exocyst is an evolutionary conserved protein complex that tethers secretory vesicle to the target membrane and consists of eight subunits: Sec3, Sec5, Sec6, Sec8, Sec10, Sec15, Exo84, and Exo70. Sec15 exocyst subunit was previously shown to connect the rest of the exocyst complex with a secretory vesicle in yeast, mammals and fruit fly via interaction with Rab GTPase and GEF of Rab GTPase. Here, I show that plant SEC15B potentially functions in evolutionary conserved manner. First, two mutant lines of Arabidopsis thaliana sec15b mutant were tested in characteristics typical for other exocyst mutants. Although some characteristics reach certain level of plasticity, both sec15b-1 and sec15b-2 show similar tendencies, which are mostly consistent with defects with other mutants in exocyst subunits. sec15b-1 has been determined as a stronger allele that is defective in formation of seed coat, elongation of etiolated hypocotyl, growth of stem and primary root, establishment of axillary branches and lateral roots, diameter of rosette and, unexpectedly, growth of pollen tubes. Phenotype of sec15b-1 was rescued by insertion of SEC15B gene under SEC15B promotor. Second, complementation test showed that SEC15B and SEC15A are...
26

Detekce kovalentních komplexů proteinů s DNA s použitím fluorescenční mikroskopie / The detection of protein covalent complexes with DNA using fluorescent microscopy

Melicharová, Růžena January 2020 (has links)
Charles University Faculty of Pharmacy in Hradec Králové Department od Biochemical Sciences Candidate: Růžena Melicharová Supervisor: PharmDr. Anna Jirkovská, Ph.D. Title of thesis: The detection of protein covalent complexes with DNA using fluorescent microscopy Anthracycline antibiotics are present one of the most potent antineoplastic drugs. The mechanism of their action is complex. They are reported to intercalate to DNA, form DNA adducts and interact with topoisomerase II (TopII) as its poisons. Catalytic cycle of TopII is interrupted when anthracyclines stabilize the covalent complex of DNA and TopII and that causes cell damage. However, using of anthracyclines is limited by several adverse effects e. g. myelotoxicity and cardiotoxicity. The mechanism of cardiotoxicity is still unclear but may be associated with poisoning of the TopIIβ isoform. Unlike the TopIIα, TopIIβ is present mostly in quiescent cells as cardiomyocytes. Furthermore, the only clinically approved cardioprotective drug dexrazoxane belongs to TopII catalytic inhibitors. Nevertheless, the details of the dexrazoxane-afforded protection are unclear. This thesis was aimed to optimize the TARDIS (trapped in agarose DNA immunostaining) assay to detect and quantify covalent cleavage complexes, compare different ways for analysis of...
27

Komplexy polydentátních ligandů / Complexes of polydentate ligands

Sedláčková, Simona January 2020 (has links)
Polydentate ligands are useful in many industries, mainly because of their ability to form complexes. The aim of this thesis is to study acid-base and coordination properties of polydentate ligands from the group of polyaminopolyphosphonates DTPMP and HMDTMP. The protonation constants of ligands as well as stability constants of complexes with biologically relevant ions Cu2+ , Zn2+ , Ni2+ , Mg2+ , Ca2+ , Co2+ , K+ and Na+ were determined by potentiometric titration. 31 P-NMR titration was used to determine pKa on nitrogen atoms, which could not be measured by potenciometric titration. Seven pKa for HMDTMP ligand and nine for DTPMP were obtained. The stability constants show that the HMDTMP ligand forms less stable complexes than the DTPMP ligand.
28

Development of new syntheses of condensed aromatic compounds / Development of new syntheses of condensed aromatic compounds

Kaiser, Reinhard Peter January 2018 (has links)
This work is divided into two parts that are focused on the synthesis and assessment of photophysical properties of two structurally related compounds: (i) 9,9'-spirobifluorenes (SBFs) and (ii) dispiroindeno[2,1-c]fluorenes (DS-IFs). (i) In the first part, a five-step synthetic approach to SBFs was developed and as the crucial step was used an intermolecular [2+2+2] cyclotrimerization of symmetrically or unsymmetrically substituted diynols with alkynes catalyzed by Rh-complexes. Catalyst screening showed that Wilkinson's catalyst (RhCl(PPh3)3) had the highest efficiency in yielding 1,2,3,4-substituted fluorenols - the key intermediates. The fluorenols were then converted into SBFs bearing various electron-donating and -withdrawing groups, aromatic substituents, and -extended aromatic hydrocarbon moieties (PAHs). Altogether 19 different SBFs were prepared and their photophysical properties screened. The fluorescent emission maxima em were in the range of 315-389 nm with excellent quantum yields s (up to 1.00). As far as the substituent effect is concerned the presence of electron-withdrawing substituents on the SBF scaffold results in the red-shift of the emission maxima. (ii) In the second part, a similar synthetic strategy was applied for synthesis DS-IFs. In this instance was utilized again the...
29

Elektroforetické stanovení tantalu v recyklátech chladicích kapalin / Electrophoretic Determination of Tantalum in Recycled Coolants

Gogulin, Semen January 2021 (has links)
This master thesis deals with the development of electrophoretic methods for determination of tantalum in recycled coolants used in the production of tantalum capacitors, as well as the separation of tantalum from chemically similar niobium. Developed methods are based on the formation of negatively charged complexes of tantalum and niobium with a number of ligands added to the separation electrolyte, especially tartaric and citric acid and 4-(2-pyridylazo)resorcinol. The separations were performed in a fused silica capillary of the inner diameter of 50 µm and the effective length of 36.5 cm, a negative voltage of -25 kV was applied to the capillary. Using a separation electrolyte containing 0.1 mol·l-1 of tartaric and citric acid at pH = 2, separation of niobium and tantalum was achieved in less than 3 minutes; the absorption spectrometric detection was carried out in the ultraviolet region at a wavelength of 200 nm, the detection limit was 2.8 ppm of tantalum, and the quantification limit was 9.2 ppm of tantalum. Addition of 4-(2-pyridylazo)resorcinol reduced the detection limit to 0.8 ppm of tantalum and the quantification limit to 2.6 ppm of tantalum; the electrolyte contained 0.1 mmol·l-1 of 4-(2-pyridylazo)resorcinol, 10 mmol·l-1 of tartaric acid, 10 mmol·l-1 of citric acid, and 25 mmol·l-1...
30

Komplexy 2,6-bis[(N-methylpiperazin-1-yl)methyl]-4-formyl fenolu / Complexes of 2,6-bis[(N-methylpiperazine-1-yl)methyl]-4-formyl phenol

Marečková, Vendula January 2012 (has links)
Thirteen new dinuclear complexes of ligand 2,6-bis[(N-methylpiperazine-1- yl)methyl]-4-formyl phenol (L1) were prepared. Copper(II) and palladium(II) salts were used for the syntheses. Following compounds were prepared: [Cu2L1(CH3COO)2]ClO4, [Cu2L1(CF3COO)2(ClO4)][Cu2L1(CF3COO)2]ClO4, [Pd2L1(CH3COO)3], [Pd2L1(CF3COO)3], [Pd2L1(Cl)4]. These ones should act as anion receptors. The acetates were exchanged for phenylphosphinates in the case of the complex cation [Cu2L1(CH3COO)2]+ and the structure of [Cu2L1(phPO2H)2]ClO4 was obtained. Geometry of coordination shell of Cu2+ - ions in prepared complexes is tetragonal pyramid. The UV-VIS spectroscopy was used for study of interactions in system of the ligand - metal - anion. Interactions between the ligand and metals in oxidation state 2 were observed as well as interactions between the complex [Cu2L1(CH3COO)2]ClO4 and sodium salts.

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