Determinación experimental del tiempo de evolución de procesos de cambios conformacionales en Hemoglobina humana mediante técnicas de Resonancia Magnética Nuclear

Tesis (Lic.en Física)--Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física, 2010.Este trabajo se orienta al estudio de procesos de cambios conformacionales de la molécula de hemoglobina A al ser extraída de su ambiente natural (eritrocitos). Para ello se realizaron mediciones del tiempo de relajación espín-red de protones en función del tiempo y de campo local en el sistema rotante. Estos experimentos fueron complementados con cromatografía de filtración molecular, filtraciones por centrifugación y espectroscopía de infrarrojo. A partir de los resultados obtenidos es posible determinar los tiempos de evolución de dos procesos diferentes, que en este trabajo se atribuyen a la dimerización del tetrámero de hemoglobina A debido al proceso de desoxigenación espontanea, y en segundo lugar, a una gelificación débil por afinidad de los dímeros.Carla Cecilia Fraenza

Caracterización de la dinámica molecular en nanoestructuras supramoleculares globulares mediante relaxometría magnética nuclear

Tesis (Doctor en Física)--Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía, Física y Computación, 2016.Utilizando diferentes técnicas de resonancia magnética nuclear, principalmente la relaxometría con ciclado rápido de campo magnético, se llevaron a cabo estudios de dinámica molecular, los que permitieron analizar propiedades mesoscópicas en diferentes estructuras supramoleculares globulares. Se midió la tasa de relajación espín-red de protones con esta técnica, en liposomas unilamelares. Se extendió exitosamente a sistemas más complejos (liposomas dopados con colesterol o detergente) un modelo previamente desarrollado para interpretar la dispersión de dicha tasa. Este modelo proporciona información general sobre la dinámica de los lípidos que conforman la membrana de los liposomas y nos permite inferir sobre las propiedades elásticas de la misma por medio de la constante elástica de flexión k. En el caso de mediciones de k para liposomas rígidos dopados con colesterol (k ~15-20kBT), fue posible dilucidar experimentalmente la cantidad de lípidos que son afectados por cada molécula de colesterol.Using different nuclear magnetic resonance techniques, mainly fast field cycling relaxometry, molecular dynamics studies were carried out, and that allowed analyzing mesoscopic properties of different globular supramolecular structures. Protons spin-lattice relaxation rate of unilamellar liposomes was measured through this technique. A previous developed model to interpret the dispersion of that rate was extended to more complex systems successfully (liposomes with cholesterol or detergent). This model provides general information about the dynamics of lipids of the liposome membrane and allows us to infer about elastic properties of the membrane by means of the bending modulus k. For measurements of k of rigid liposomes with cholesterol (k ~15-20kBT), it was possible to elucidate the amount of lipids affected by every cholesterol molecule, experimentally

Evolution of microscopic heterogeneity and dynamics in choline chloride-based deep eutectic solvents

Deep eutectic solvents (DESs) are an emerging class of non-aqueous solvents that are potentially scalable, easy to prepare and functionalize for many applications ranging from biomass processing to energy storage technologies. Predictive understanding of the fundamental correlations between local structure and macroscopic properties is needed to exploit the large design space and tunability of DESs for specific applications. Here, we employ a range of computational and experimental techniques that span length-scales from molecular to macroscopic and timescales from picoseconds to seconds to study the evolution of structure and dynamics in model DESs, namely Glyceline and Ethaline, starting from the parent compounds. We show that systematic addition of choline chloride leads to microscopic heterogeneities that alter the primary structural relaxation in glycerol and ethyleneglycol and result in new dynamic modes that are strongly correlated to the macroscopic properties of the DES formed

Dynamical regimes of lipids in additivated liposomes with enhanced elasticity: A field-cycling NMR relaxometry approach

We study the molecular dynamics of lipids in binary large unilamellar liposomes suspended in D2O composed of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) or soy phosphatidylcholine (SPC) additivated with different percentiles of sodium deoxycholate (SDC). We use the fast field-cycling proton NMR relaxometry technique over a wide timescale and at diverse temperatures. A model previously validated in different formulations is here employed for the relaxometric analysis of elastic vesicles. A new dynamical regime is observed for the first time in additivated DMPC and additivated/non-additivated SPC liposomes. This surprising feature is discussed in terms of vesicle shape fluctuations, enhanced elasticity and lipid & additive diffusion within the membrane. The continuum elastic theory is revisited for a better understanding of recent experiments and those here presented. We address the point of deformability measurements across rigid permeable barriers versus measurements of the bending elastic modulus in free-standing vesicles.Fil: Fraenza, Carla Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; ArgentinaFil: Anoardo, Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentin

The Effect of Cholesterol on Membrane Dynamics on Different Timescales in Lipid Bilayers from Fast Field-Cycling NMR Relaxometry Studies of Unilamellar Vesicles

The general applicability of fast field-cycling nuclear magnetic resonance relaxometry in the study of dynamics in lipid bilayers is demonstrated through analysis of binary unilamellar liposomes composed of 1,2-dioleoyl-sn-glycero-3-posphocholine (DOPC) and cholesterol. We extend an evidence-based method to simulating the NMR relaxation response, previously validated for single-component membranes, to evaluate the effect of the sterol molecule on local ordering and dynamics over multiple timescales. The relaxometric results are found to be most consistent with the partitioning of the lipid molecules into affected and unaffected portions, rather than a single averaged phase. Our analysis suggests that up to 25 mol%, each cholesterol molecule orders three DOPC molecules, providing experimental backup to the findings of many molecular dynamics studies. A methodology is established for studying dynamics on multiple timescales in unilamellar membranes of more complex compositions.Fil: Fraenza, Carla Cecilia. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; ArgentinaFil: Meledandri, Carla J.. Universidad de Dublin; Irlanda. University of Otago; Nueva ZelandaFil: Anoardo, Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; ArgentinaFil: Brougham, Dermot F.. Universidad de Dublin; Irland

Nuclear Magnetic Resonance Relaxation Pathways in Electrolytes for Energy Storage

Nuclear Magnetic Resonance (NMR) spin relaxation times have been an instrumental tool in deciphering the local environment of ionic species, the various interactions they engender and the effect of these interactions on their dynamics in conducting media. Of particular importance has been their application in studying the wide range of electrolytes for energy storage, on which this review is based. Here we highlight some of the research carried out on electrolytes in recent years using NMR relaxometry techniques. Specifically, we highlight studies on liquid electrolytes, such as ionic liquids and organic solvents; on semi-solid-state electrolytes, such as ionogels and polymer gels; and on solid electrolytes such as glasses, glass ceramics and polymers. Although this review focuses on a small selection of materials, we believe they demonstrate the breadth of application and the invaluable nature of NMR relaxometry

Use of 1H-NMR spectroscopy, diffusometry and relaxometry for the characterization of thermally-induced degradation of motor oils

We explore the capability of 1H NMR spectroscopy, relaxation and diffusion for the characterization of thermally-induced degradation of fresh motor oils. Temperature dependent measurements of diffusion show a weak sensitivity to thermal degradation. In contrast, both the transverse relaxation at 1H Larmor frequencies of 20 MHz and 400 MHz, as well as the longitudinal relaxation at 60 kHz showed to be sensitive to thermally-induced effects at measured temperatures within the range −10 °C to 30 °C. Results show that the highest sensitivity significance can be reached by fast field-cycling NMR relaxometry measurements at low magnetic fields.Fil: Fraenza, Carla Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; ArgentinaFil: Förster, E.. Karlsruher Institut fur Technologie; AlemaniaFil: Guthausen, Gisela. Karlsruher Institut fur Technologie; AlemaniaFil: Nirschl, Hermann. Karlsruher Institut fur Technologie; AlemaniaFil: Anoardo, Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentin

NMR relaxometry analysis of molecular degradation in internal combustion engine lubricants

A set of experimental techniques headed by proton fast field-cycling nuclear magnetic resonance (1HFFC-NMR) were used to analyze the effects of degradation of lubricant oil used in an internal combustion engine (ICE). Its relaxometric, spectroscopic, and rheological properties were evaluated and interpreted in terms of changes in the chemical structure and the involved molecular dynamics. In order to better understand the relaxometric behavior, chemical changes induced by heat were investigated for selected n-alkanes, as model-systems due to their structural simplicity. Fourier transform infrared (FTIR) spectroscopy, viscosity measurements, and foaming were used to contrast NMR relaxometry experiments. Main observed changes associated with oil degradation can be attributed to molecular oxidation, fragmentation, and ramification. As an outstanding feature of this work, we show that the relaxometric analysis can be done without any special treatment of the sample, allowing results in less than 10 min.Fil: Erro, Eustaquio Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina. Universidad Nacional de Córdoba; Facultad de Matemática, Astronomía, Física y Computación; Laboratorio de Relaxometría y Técnicas Especiales (LaRTE); ArgentinaFil: Gerbino, Leandro Julian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina. Universidad Nacional de Córdoba; Facultad de Matemática, Astronomía, Física y Computación; Laboratorio de Relaxometría y Técnicas Especiales (LaRTE); ArgentinaFil: Fraenza, Carla Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina. Universidad Nacional de Córdoba; Facultad de Matemática, Astronomía, Física y Computación; Laboratorio de Relaxometría y Técnicas Especiales (LaRTE); ArgentinaFil: Anoardo, Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina. Universidad Nacional de Córdoba; Facultad de Matemática, Astronomía, Física y Computación; Laboratorio de Relaxometría y Técnicas Especiales (LaRTE); Argentin

Monitoring lubricant oil degradation using field-cycling NMR relaxometry

Proton fast field-cycling nuclear magnetic resonance (1 HFFC-NMR) was used to study the effect of thermal stress in mineral base oil. The base oil underwent controlled thermal degradation and its relaxometric response was evaluated and interpreted in terms of self-diffusion and molecular rotations. Our results show slight changes in the relaxometric behaviour corresponding to samples exposed at typical engine working temperature (T = 90◦C),), whereas extreme heating treatment (T= 270◦C)) have produced degradation that is clearly evidenced in the profiles, particularly at low Larmor frequencies. Additionally, diffusion coefficients were calculated using a simplified method, showing the expected physical tendency with temperature and degradation level.Fil: Erro, Eustaquio Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; ArgentinaFil: Fraenza, Carla Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; ArgentinaFil: Gerbino, Leandro Julian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; ArgentinaFil: Anoardo, Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentin

Rouse dynamics in PEO-PPO-PEO block-copolymers in aqueous solution as observed through fast field-cycling NMR relaxometry

We present a proton fast field-cycling (FFC) NMR relaxometry study of the molecular dynamics in three different deuterated water-dispersed triblock copolymers of ethylene oxide (EO) and propylene oxide (PO):EO80PO27EO80(F68), EO141PO44EO141 (F108), and EO101PO56EO101(F127). Independently of the phase and molecular arrangement, bi-exponential decays of the magnetization during the spin-lattice relaxation process could be observed for F127, while mono-exponential decays were measured for F68 and F108. This fact has been attributed to the relative ratio of PEO and PPO protons for each case. In F127, each component of the magnetization decay could be associated with a particular block of the co-polymer. A direct consequence of this fact is the independent characterization of the molecular dynamics of each block. It was found that the dominant relaxation mechanism can be attributed to the Rouse model, and it seems to be independent on whether the molecules are incorporated into a micelle, or as individual unimers in the aqueous solution. The experimental results and the provided explanation are consistent with entanglement-free self-assembled structures, and a fast exchange of unimers between the micellar structure and the solvent. This particular feature was also investigated in F68 and F108, although for these cases a mono-exponential decay of the magnetization was observed. NMR relaxometry results are complemented with other relaxation experiments in the rotating frame, NMR spectroscopy and atomic-force microscopy.Fil: Fraenza, Carla Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; ArgentinaFil: Mattea, Carlos. Technische Universität Ilmenau; AlemaniaFil: Farrher, German David. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; ArgentinaFil: Ordikhani Seyedlar, Amín. Tecnische Universität Ilmenau; AlemaniaFil: Stapf, Siegfried. Tecnische Universität Ilmenau; AlemaniaFil: Anoardo, Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentin