<p>Ekstrakcijom heksanom, a zatim 80% etanolom predhodno pripremljenog tropa od<br />IZ odabranih genotipova Bačka, Knjaz, Novosadski niski, O₂, Rutgers i Saint Pierre<br />paradajza, dobijeni su heksanski i etanolni ekstrakti tropa. Sadržaj karotenoida u<br />heksanskim i polifenolnih jedinjenja, flavonoida i askorbinske kiseline u etanolnim<br />ekstraktima određen je spektrofotometrijskim metodama. Identifikacija i<br />kvantifikacija pojedinih karotenoida u heksanskim i polifenolnih jedinjenja u<br />etanolnim ekstraktima tropa paradajza izvedena je HPLC analizom. U ostacima<br />nakon ekstrakcija tropa paradajza određen je sadržaj prehrambenih vlakana.<br />Spektrofotometrijskim testovima određena je antiradikalska aktivnost na DPPH<br />radikale i redukciona sposobnost dobijenih ekstrakata. ESR spektroskopijom<br />ispitan je uticaj etanolnih ekstrakata na reaktivne hidroksil i superoksid anjon<br />radikale. Pored toga, ispitana je i helirajuća sposobnost etanolnih ekstrakata.<br />Antiradikalsko delovanje na DPPH radikale ostataka nakon ekstrakcija tropa<br />paradajza radikale, takođe je utvrđeno. Ispitana je in vitro antiproliferativna<br />aktivnost frakcija ekstrakata, njihovim delovanjem na rast tri histolo&scaron;ki različite<br />humane ćelijske linije: MCF-7 (adenokarcinom dojke), HeLa (epitelni karcinom<br />cerviksa) i MRC-5 (fetalni fibroblastni karcinom pluća). Rezultati ispitivanja<br />hemijskog sastava, antioksidativne i antiproliferativne aktivnosti ekstrakata, kao i<br />ostataka nakon ekstracija tropa odabranih genotipova paradajza ukazuju na<br />mogućnost iskori&scaron;ćenja ovog sporednog proizvoda kao potencijalnog izvora<br />prirodnih antioksidanata, koji bi na&scaron;li primenu u prehrambenoj, farmaceutskoj i<br />kozmetičkoj industriji.</p> / <p>Tomato pomaces obtained from selected tomato genotypes (Bačka, Knjaz, Novosadski niski,<br />O2, Rutgers and Saint Pierre) were extracted sequentially with hexane and 80% ethanol. The<br />content of carotenoids i hexane and total polyphenolics, flavonoids and ascorbic acid in<br />ethanolic extracts was determined by spectrophotometric methods. Identification and<br />quantification of individual carotenoids in hexane and polyphenolics in ethanolic extracts<br />was determined by HPLC analysis. The content of dietary fiber was determined in the<br />residues after extraction of tomato pomaces. The scavenging activity on DPPH radicals and<br />reducing power of the obtained extracts were determined spectrophotometrically. The<br />influence of ethanolic extracts on reactive hydroxyl and superoxide anion radicals was<br />examined by electron spin resonance (ESR) spectroscopy. In addition, the chelating ability of<br />ethanolic extracts was investigated. Scavenging effect on DPPH radicals of the residue after<br />extraction of tomato pomace, has also been established. Antiproliferative activity of<br />investigated extracts was determined in vitro, testing their influence on the growth of three<br />histologically different human cell lines: MCF-7 (breast adenocarcinoma), HeLa (cervix<br />epithelioid carcinoma) and MRC-5 (fetal lung). Based on the results of chemical analysis,<br />significant antioxidant and antiproliferative activity of the tomato waste extracts, as well as<br />residues after extraction showed that tomato waste obtained from different tomato genotypes<br />should be regarded as potential source of natural antioxidants, which can be used for various<br />purposes in the food, pharmaceutical and cosmetic industry.</p>

Due to recent progress in theory and the growing number of physical realizations, low-dimensional quantum magnets continue to receive a considerable amount of attention. They serve as model systems for investigating numerous physical phenomena in spin systems with cooperative ground states, including the field-induced evolution of the ground-state properties and the corresponding rearrangement of their low-energy excitation spectra. This work is devoted to systematic studies of recently synthesized low-dimensional quantum spin systems by means of multi-frequency high-field electron spin resonance (ESR) investigations. In the spin- 1/2 chain compound (C6H9N2)CuCl3 [known as (6MAP)CuCl3] the striking incompatibility with a simple uniform S = 1/2 Heisenberg chain model employed previously is revealed. The observed ESR mode is explained in terms of a recently developed theory, revealing the important role of the alternation and next-nearest-neighbor interactions in this compound. The excitations spectrum in copper pyrimidine dinitrate [PM·Cu(NO3)2(H2O)2]n, an S = 1/2 antiferromagnetic chain material with alternating g-tensor and Dzyaloshinskii-Moriya interaction, is probed in magnetic fields up to 63 T. To study the high field behavior of the field-induced energy gap in this material, a multi-frequency pulsed-field ESR spectrometer is built. Pronounced changes in the frequency-field dependence of the magnetic excitations are observed in the vicinity of the saturation field, B ∼ Bs = 48.5 T. ESR results clearly indicate a transition from the soliton-breather to a spin-polarized state with magnons as elementary excitations. Experimental data are compared with results of density matrix renormalization group calculations; excellent agreement is found. ESR studies of the spin-ladder material (C5H12N)2CuBr4 (known as BPCB) completes the determination of the full spin Hamiltonian of this compound. ESR results provide a direct evidence for a pronounced anisotropy in this compound, that is in contrast to fully isotropic spin-ladder model employed previously for BPCB. Our observations can be of particular importance for describing the rich temperature-field phase diagram of this material. The frequency-field diagram of magnetic excitations in the quasi-two dimensional S = 1/2 compound [Cu(C4H4N2)2(HF2)]PF6 in the AFM-ordered state is studied. The AFM gap is observed directly. Using high-field magnetization and ESR results, parameters of the effective spin-Hamiltonian (exchange interaction, anisotropy and g-factor) are obtained and compared with those estimated from thermodynamic properties of this compound.

Die Arbeit befasst sich mit der Elektronenspinresonanz (ESR) stark korrelierter Elektronensysteme mit ferromagnetischen Wechselwirkungen. Es wurden dafür Messungen an den Kondogitter-Systemen CeRuPO und CeOsPO, der Dotierungsreihe CeFeAs1-xPxO, den niederdimensionalen frustrierten Quadratgittern AA’VO(PO4)2 sowie in dem schwach ferromagnetischen Metall Nb1-yFe2+y durchgeführt. Alle Verbindungen zeigen entweder eine ferromagnetische Ordnung oder befinden sich in der Nähe einer ferromagnetischen Instabilität, die die Eigenschaften des stark korrelierten Systems beeinflusst.:Abkürzungsverzeichnis xi Einleitung 1 1 Theoretische Modelle 5 1.1 Auswirkungen des Kristallfeldes 1.2 Phasenübergänge, Landau-Ginzburg Theorie und Quantenphasenübergänge 1.3 Physik Niederdimensionaler Spin-Systeme 1.3.1 Das zweidimensionale XY-Modell 1.3.2 Das J1-J2-Modell auf dem Quadratgitter 1.4 4f-Magnetismus, Kondoeffekt und Kondogitter 1.4.1 Vom freien Elektronengas zur Landau-Fermi-Flüssigkeit 1.4.2 Kondo-Effekt, RKKY-Wechselwirkung und Schwere Fermionen Systeme 1.4.3 Cer: 4f-Magnetismus 1.5 Schwach magnetische Metalle 1.5.1 Pauli-Suszeptibilität und spontan aufgespaltene Bänder 1.5.2 Spinfluktuationen in itineranten Magneten und marginale Fermiflüssigkeit 1.6 Dichtefunktionaltheorie 2 Grundlagen der Elektronenspinresonanz 31 2.1 Prinzip der magnetischen Resonanz und ESR Parameter 2.1.1 Linienform 2.1.2 Intensität 2.1.3 g-Faktor 2.1.4 Linienbreite und Spin-Relaxation 2.2 Experimenteller Aufbau 2.3 ESR in niederdimensionalen Systemen 2.4 ESR an Metallen und Kondogitter Systemen 2.4.1 Auswirkungen der Wechselwirkungen zwischen lokalen Momenten und Leitungselektronen auf die ESR 2.4.2 ESR in Kondogittersystemen 2.5 Leitungselektronenspinresonanz 2.5.1 Linienform in der LESR 2.5.2 Elliot-Yafet Theorie und ihre Verallgemeinerung 2.6 ESR an magnetischen Phasenübergängen 3 ESR in CeTPO (T=Ru, Os) und CeFeAs1-xPxO 59 3.1 Die Eigenschaften von CeTPO (T=Ru, Os) & CeFeAs1-xPxO 3.1.1 Das ferromagnetische Kondogitter CeRuPO 3.1.2 Das antiferromagnetische Kondogitter CeOsPO 3.1.3 Die Dotierungsreihe CeFeAs1-xPxO 3.2 CeRuPO und CeOsPO: Die Bedeutung FM Fluktuationen für die Beobachtbarkeit der ESR in Kondo-Gitter Systemen 3.3 ESR an CeRuPO Einkristallen 3.3.1 Anisotropie und Temperaturverhalten des g-Faktors 3.3.2 Anisotropie und Temperaturverhalten der Linienbreite 3.4 Entwicklung der ESR in der Dotierungsreihe CeFeAs1-xPxO 3.4.1 CeFeAs0.7P0.3O - Supraleitung und Ferromagnetismus 3.5 Zusammenfassung ESR in CeTPO und CeFeAs1-xPxO 4 ESR in den frustrierten Quadratgittern AA’VO(PO4)2 97 4.1 Struktur und magnetische Eigenschaften AA’VO(PO4)2 4.2 ESR an polykristallinen SrZnVO(PO4)2 & BaCdVO(PO4)2 4.2.1 SrZnVO(PO4)2 4.2.2 BaCdVO(PO4)2 4.3 ESR an Pb2VO(PO4)2-Einkristallen 4.3.1 Anisotropie der Resonanz 4.3.2 Temperaturabhängigkeit 4.4 Zusammenfassung der ESR in den frustrierten Quadratgittern 7 4.4.1 Analyse der Linienbreitendivergenz am Phasenübergang 5 Leitungselektronenspinresonanz in Nb1-yFe2+y 125 5.1 Das magnetische Phasendigramm von Nb1-yFe2+y 5.2 LESR in polykristallinen Nb1-yFe2+y 5.2.1 Proben mit ferromagnetischer Ordnung 5.2.2 Proben mit SDW-Ordnung 5.2.3 Zusammenfassung polykristalline Proben 5.3 Bandstruktur und verallgemeinerte Elliot-Yafet-Theorie in NbFe2 5.4 LESR in einkristallinen Proben von Nb1-yFe2+y 5.4.1 Fe-reicher Einkristall: y=0.016 5.4.2 Stöchiometrischer Einkristall: NbFe2 5.4.3 Nb-reicher Einkristall: y=-0.008 5.5 Zusammenfassung LESR in Nb1-yFe2+y 6 Zusammenfassung und Ausblick Anhang A.1 Das zweite Moment der Dipol-Dipol-Wechselwirkung A.2 Untersuchte CeFeAs1-xPxO-Proben Literaturverzeichnis

To optimize contrast agent in MRI scan region, e.g. to enhance paramagnetic relaxation in the MRI scan fields(0.1T-3T), one possible way is to slow down the tumbling of the paramagnetic complex. The effect of slowing down the reorientational motion of the complex to increase relaxivity is obvious and this strategy has already been employed in producing MRI contrast agent that can bind to specific proteins. An example is MS-325 binds to human serum albumin(HSA). The slow down effects on the ligands around paramagnetic ion, and on the zero field splitting(ZFS) interaction are under studies and the physics behind is still not clear. In this thesis, a generalized Solomon-Bloembergen-Morgan(GSBM) theory together with stochastic Liouville approach(SLA), is applied to investigate the mechanism behind the slow down effects. Two gadolinium complexes, MS-325+HSA and Gd(H2O)83++glycerol are studied by means of NMRD and ESR experiments. GSBM is a second order perturbation theory with closed analytical form. The computation based on this theory is fast, but it has its limitation and in the case of Gd(S=7/2) the ZFS strength times its correlation time(Δt.τƒ) should be less than 0.1. In comparison, the SLA is an "exact" theory that can evaluate the validity of GSBM calculation. However, the calculation in SLA is time consuming due to the large matrix it constructed. The major model used in GSBM is a two dynamic model, characterized by transient ZFS Δt and static ZFS Δs and their corresponding correlation time τƒ and τR, while in SLA the model is only described by Δt and τƒ. A combined NMRD and ESR analysis is used to understand the details of ZFS interaction. Both models can reproduce experimental NMRD profiles and model parameters are similar; for ESR linewidths the model parameters are quite different. The fitting results indicate the NMRD profiles are less sensitive to the detail expression of ZFS correlation function. In order to interpret both NMRD and ESR experiments with identical parameters, a more complex ZFS interaction model should be developed.

Due to the extreme properties of diamond, such as extreme hardness, high thermal conductivity, high electrical breakdown strength, high electron and hole mobilities and large band gap, it is of interest to study this material in detail. Before advantage can be taken of diamond’s properties for high-temperature, high-power electronic applications successful doping/ion implantation of diamond must be achieved. This requires an understanding of the types of defects produced during ion irradiation. In the present work, type IIa diamond has been irradiated with various doses of 320keV Xe ions at room temperature. Analytical techniques used are electron spin resonance spectroscopy, Raman spectroscopy, transmission electron microscopy and electron energy loss spectroscopy. Previous models have suggested that upon ion impact, amorphous and/or graphitized clusters are formed in diamond, which will overlap at a critical dose to form a semi-continuous graphitized layer. (For complete abstract open document)

Due to the extreme properties of diamond, such as extreme hardness, high thermal conductivity, high electrical breakdown strength, high electron and hole mobilities and large band gap, it is of interest to study this material in detail. Before advantage can be taken of diamond’s properties for high-temperature, high-power electronic applications successful doping/ion implantation of diamond must be achieved. This requires an understanding of the types of defects produced during ion irradiation. In the present work, type IIa diamond has been irradiated with various doses of 320keV Xe ions at room temperature. Analytical techniques used are electron spin resonance spectroscopy, Raman spectroscopy, transmission electron microscopy and electron energy loss spectroscopy. Previous models have suggested that upon ion impact, amorphous and/or graphitized clusters are formed in diamond, which will overlap at a critical dose to form a semi-continuous graphitized layer. (For complete abstract open document)

<p>To optimize contrast agent in MRI scan region, e.g. to enhance paramagnetic relaxation in the MRI scan fields(0.1T-3T), one possible way is to slow down the tumbling of the paramagnetic complex. The effect of slowing down the reorientational motion of the complex to increase relaxivity is obvious and this strategy has already been employed in producing MRI contrast agent that can bind to specific proteins. An example is MS-325 binds to human serum albumin(HSA). The slow down effects on the ligands around paramagnetic ion, and on the zero field splitting(ZFS) interaction are under studies and the physics behind is still not clear. In this thesis, a generalized Solomon-Bloembergen-Morgan(GSBM) theory together with stochastic Liouville approach(SLA), is applied to investigate the mechanism behind the slow down effects. Two gadolinium complexes, MS-325+HSA and Gd(H₂O)₈³⁺+glycerol are studied by means of NMRD and ESR experiments.</p><p>GSBM is a second order perturbation theory with closed analytical form. The computation based on this theory is fast, but it has its limitation and in the case of Gd(S=7/2) the ZFS strength times its correlation time(Δ<i>t</i>.<i>τ</i>_ƒ) should be less than 0.1. In comparison, the SLA is an "exact" theory that can evaluate the validity of GSBM calculation. However, the calculation in SLA is time consuming due to the large matrix it constructed. The major model used in GSBM is a two dynamic model, characterized by transient ZFS Δ<i>t</i> and static ZFS Δ<i>s</i> and their corresponding correlation time <i>τ</i>_ƒ and <i>τR</i>, while in SLA the model is only described by Δ<i>t</i> and <i>τ</i>_ƒ. A combined NMRD and ESR analysis is used to understand the details of ZFS interaction. Both models can reproduce experimental NMRD profiles and model parameters are similar; for ESR linewidths the model parameters are quite different. The fitting results indicate the NMRD profiles are less sensitive to the detail expression of ZFS correlation function. In order to interpret both NMRD and ESR experiments with identical parameters, a more complex ZFS interaction model should be developed.</p>

<p>This thesis describes water proton and deuterium relaxation processes, as seen by Nuclear Magnetic Resonance (NMR) spectroscopy, using Brownian Dynamics (BD) or Molecular Dynamics (MD) simulations. The MD simulations reveal new detailed information about the dynamics and order of water molecules outside of a lipid bilayer. This is very important information in order to fully understand deuterium NMR measurements in lipid bilayer systems, which require an advanced analysis, because of the complicated water motion (such as tumbling and self-diffusion). The BD simulation methods are combined with the powerful Stochastic Liouville Equation (SLE) in its Langevin form (SLEL) to give new insight into both ¹H₂O and ²H₂O relaxation. The new simulation techniques which combine BD and SLEL can give important new information in cases where other methods do not apply. The deuterium relaxation is described in the context of a water/lipid interface and is in a very elegant way combined with the simulation of diffusion on curved surfaces developed by our research group. ¹H₂O spin-lattice relaxation is described for paramagneticsystems. With this we mean systems with paramagnetic transition metal ions or complexes, that are dissolved into a water solvent. The theoretical description of such systems are quite well investigated but such systems are not yet fully understood. An important consequence of the Paramagnetic Relaxation Enhancement (PRE) calculations when using the SLEL approach combined with BD simulations is that we obtain the electron correlation functions, which describe the relaxation of the paramagnetic electron spins. This means for example that it is also straight forward to generate Electron Spin Resonance (ESR) lineshapes.</p>

This thesis describes water proton and deuterium relaxation processes, as seen by Nuclear Magnetic Resonance (NMR) spectroscopy, using Brownian Dynamics (BD) or Molecular Dynamics (MD) simulations. The MD simulations reveal new detailed information about the dynamics and order of water molecules outside of a lipid bilayer. This is very important information in order to fully understand deuterium NMR measurements in lipid bilayer systems, which require an advanced analysis, because of the complicated water motion (such as tumbling and self-diffusion). The BD simulation methods are combined with the powerful Stochastic Liouville Equation (SLE) in its Langevin form (SLEL) to give new insight into both 1H2O and 2H2O relaxation. The new simulation techniques which combine BD and SLEL can give important new information in cases where other methods do not apply. The deuterium relaxation is described in the context of a water/lipid interface and is in a very elegant way combined with the simulation of diffusion on curved surfaces developed by our research group. 1H2O spin-lattice relaxation is described for paramagneticsystems. With this we mean systems with paramagnetic transition metal ions or complexes, that are dissolved into a water solvent. The theoretical description of such systems are quite well investigated but such systems are not yet fully understood. An important consequence of the Paramagnetic Relaxation Enhancement (PRE) calculations when using the SLEL approach combined with BD simulations is that we obtain the electron correlation functions, which describe the relaxation of the paramagnetic electron spins. This means for example that it is also straight forward to generate Electron Spin Resonance (ESR) lineshapes.

ABSTRACT PLASMA SURFACE MODIFICATION AND CHARACTERIZATION OF PMMA FILMS &Ouml / zgen, &Ouml / zge M.Sc., Department of Polymer Science and Technology Supervisor: Prof. Dr. Nesrin Hasirci Co-supervisor: Prof. Dr. Vasif Hasirci December 2011, 114 pages Surface properties play an essential role for determining the behavior of a material for many applications such as coating, printing, adhesion and prosthesis implanting since the surface is the first part that comes in contact with the environment. Although the bulk properties of some materials are at the desired level, the surface may need to be modified for a better compatibility with its surrounding. Plasma treatment is one generally preferred technique because of its high potential to create various functional groups on the surface of the sample by changing the applied plasma parameters. Some molecules can be successfully immobilized onto these surfaces using these specific chemical functional groups created by plasma. The type of the functional group is important for intended purpose of covalent binding of different molecules on the surface of a material. Present study offers important routes for optimization of the surface functionality of (PMMA) films by changing the plasma parameters. For this purpose, solvent casted polymethylmetacrylate PMMA films were modified by, nitrogen, argon and oxygen plasma by using a radiofrequency (RF) generator / and with various powers (10W, 50W, 100W) for different periods (5min, 15min and 30min). The effects of these plasma parameters (gas type, applied power, plasma time) on hydrophilicity, surface free energy, surface chemistry, and surface topography were investigated. Also, the types of surface free radicals created with oxygen plasma treatment were analysed and the decay of these radicals were examined by Electron Spin Resonance Spectroscopy (ESR). In general, plasma treatment reduced the contact angle of PMMA films where the most hydrophilic surface was obtained for 100W 30 min argon plasma treated sample showing superhydrophilic character with the water contact angle value of ~10&deg / . Surface free energy measurements were carried out according to Geometric Mean, Harmonic Mean, Acid-Base approach and it was found that oxygen, nitrogen and argon plasma treatments increased the surface free energy for all samples by increasing the polar components and introducing functional groups on the surface. X-Ray Photoelectron Spectroscopy (XPS) analysis results revealed that free carbonyl and carbonate groups were formed by oxygen plasma treatment, whereas carboxylic acid and free carbonyl groups were formed after argon plasma treatment, and imine, primary amine, amide and nitrozo groups were formed by nitrogen plasma. Atomic Force Microscopy (AFM) analysis revealed that the roughness of the surface increased considerably from ~2 nm to ~75 nm for the 100W 30 min oxygen plasma treated samples. ESR analysis indicated the presence of peroxy radicals on the surface of the oxygen plasma treated PMMA and the intensity of these radicals increased with increasing plasma power. Decay study of the newly created radicals demonstrated that after 1 month under the atmospheric conditions there were still peroxy radicals on the surface of PMMA. This functionality is important in leading time for further process for binding of different molecules to the surface of the materials for specific purposes. As a result, RF plasma was found to be an effective tool for modification of surface properties of materials with product diversity for intended purposes.