PHYSICAL CHEMISTRY

Author: GALLARDO MORENO AMPARO MARÍA.
Year: 2001.
University: EXTREMADURA.
Place of defense: FACULTAD DE CIENCIAS.
Place of preparation: FACULTAD DE CIENCIAS.

Summary: The aim of this thesis has been the study of the initial stage of the accession of pathogenic microorganisms (Enterococcus faecalis and Candida parapsilosis) for various substrates (glass, silicon, polystyrene n-hexadecano and chloroform). Para ello se ha hecho una characterization physicochemistry of the cells and the surfaces where it conducts accession, getting their zeta potential and surface tension (characterization thermodynamics), and using an atomic force microscope (AFM). From these data has been interpreted theoretically the accession using models DLVO and XDLVO and have contrasted these results with experimental data accession Invitro using a static adhesióm and a dynamic, which is based on the use of a laminar flow chamber and that resembles the conditions of accession ade in the body humano.También it has been determined the cell surface hydrophobicity of using different techniques, MATH, MATH dynamic and MATS. Completing the study, we analyzed the influence of serum, antibiotics, temperature measurement, temperature and liquid suspension culture in the previous physico-chemical properties and behavior of the adhesive microorganisms, noting that all these factors alter these properties and that prediciones thermodynamic based on the changes in the free energy of interaction, they agree on the changes observed in the accession.

Author: HERRERO GÒâMEZ MIGUEL.
Year: 2003.
University: COMPLUTENSE DE MADRID.
Place of defense: FACULTAD DE CIENCIAS QUҍMICAS.
Place of preparation: FACULTAD CC. QUҍMICAS UNIV. COMPLUTENSE.

Summary: PVC occupies a prominent place in the market for materials plÃÂ ¡sticos.Es a polÃÂmero versÃÂ ¡til, with an excellent balance of properties, good resistance to agents quÃÂmicos and low coste.En This paper deals with the study of obtenciÃÂ ³ No new polÃÂmetros derivatives of PVC with potential applications in membranes separaciÃÂ charges of gases and materials antibioadhesiÃÂ ³ n. The first part of the work has been studied modificaciÃÂ ³ n homogÃÂ © line of PVC by sustituciÃÂ ³ nucleÃÂ ³ row and gas transport properties of these new polÃÂmeros. Furthermore, we have obtained pelÃÂculas of polyvinyl chloride and polystyrene superficially modificadas.La caracterizaciÃÂ charges of surfaces obtained are realizÃÂ ³ through microscopÃÂa Raman confocal. Finally, a study has been made of the surface mobility and adhersiÃÂ ³ n bacterial new polÃÂmetros PVC.

Author: HERNҁNDEZ VELASCO REBECA.
Year: 2003.
University: COMPLUTENSE DE MADRID.
Place of defense: FACULTAD CIENCIAS QUҍMICAS.
Place of preparation: UNIVERSIDAD COMPLUTENSE MADRID.

Summary: For several aÃÂ ± os gels polimÃÂ © rich have experienced a very important development as multifunctional materials introducing a series of caracterÃÂsticas and structural properties fÃÂsicas individuals. This work has been approached from the perspective of a study bÃÂ ¡sico on formaciÃÂ ³ n, structure and properties of hydrogels for polialcohol vinÃÂlico formed by cycles congelaciÃÂ ³ n-descongelaciÃÂ charges and potential applications derived from mismos.Se have prepared and characterized by various tÃÂ © cnicas as reologÃÂa, DSC, measures swelling and tÃÂ © cynical espectroscÃÂ ³ spades as FT-IR And NMR in etado sÃÂ ³ lido, based systems higrogeles PVA as networks interpenetradas PVA / PAAc and hydrogels PVA with y-ciclodextrina (y-CD) . The results have helped to define the structure generated in hydrogels PVA due to the aplicaciÃÂ ³ n cycles congelaciÃÂ ³ n-descongelaciÃÂ charges and propose a possible mechanism gelificaciÃÂ ³ n.Asimismo have been identified the best conditions for the formaciÃÂ ³ n networks interpenetradas PVA / PAAc, studied the properties and the possible separaciÃÂ charges of phases in funciÃÂ ³ n different parÃÂ ¡meters how the concentraciÃÂ ³ n PVA, cycles congelaciÃÂ ³ n-descongelaciÃÂ charges or the degree of intersecting of PÃâ ¬ Ac.El study hydrogels PVA-YCD has allowed carectizar complex of inclusiÃÂ ³ n formed between PVA and yCD adopts a structure of type channel and confirm the mechanism gelificaciÃÂ charges for hydrogels PVA obtained by cycles congelaciÃÂ ³ n-descongelaciÃÂ ³ n.

Author: PUENTEDURA RODRҍGUEZ OLGA.
Year: 2003.
University: COMPLUTENSE DE MADRID.
Place of defense: FACULTAD DE CIENCIAS QUҍMICAS.
Place of preparation: FACULTAD CC QUҍMICAS.

Summary: The monÃÂ ³ xido bromine plays an important role in the balance of the ozone layer, both at activaciÃÂ ³ n chlorine in the polar regions and its destructive capability of ozone at any latitude and ÃÂ © little of aÃÂ ± o. This paper presents the first steps of the evoluciÃÂ ³ n seasonal monÃÂ ³ xido bromine conducted in subtropical regions analyzing spectra radiaciÃÂ ³ n diffuse the bÃÂ ³ ban celestial through espectroscopÃÂa of absorciÃÂ ³ n differential (DOAS) UV-vis ground. We have used two geometrÃÂas of observaciÃÂ ³ n: geometrÃÂa zenith and geometrÃÂa "off-axis" with the entry of light oriented horizon. With the first type of observaciÃÂ ³ n is obtained informaciÃÂ charges of absorbent whose center of mass is in the stratosphere while the second one can infer the distribuciÃÂ ³ n vertical absorbent in the free troposphere. Resigrar the absorciÃÂ charges due to species like monÃÂ ³ xido bromine whose thickness ÃÂ ³ ptico differential is of the order of 0.05% implies a strong challenge from the point of view of development of instrumentaciÃÂ ³ n. The instrument used especÃÂficamente to optimize measures gases with absorciÃÂ ³ n very dÃÂ © bil in the near ultraviolet has been developed at ÃÂ area of InvestigaciÃÂ ³ n InstrumentaciÃÂ ³ n AtmosfÃÂ © rich AIIA INTA. The espectrÃÂ ³ graph estÃÂ ¡calibrated for measuring BrO in atmÃÂ ³ sfera by the NDSC (Net for the Detection of Stratospheric Change) raÃÂz of participaciÃÂ charges in the intercomparaciÃÂ charges of instrumentaciÃÂ ³ n DOAS land for the average BrO and LEISURE developed last aÃÂ ± or Andoya (Norway). Measurements are performed by the Center AtmosfÃÂ © rich IzaÃÂ ± a (28ÃÂ º N), located at regiÃÂ ³ n subtropical between January 2002 and December 2003. IzaÃÂ ± a is an excellent location for observaciÃÂ ³ n ÃÂ ³ ptica of atmÃÂ ³ sfera. We have obtained the vertical columns of BrO during the measure, which allows its seasonal variability in this regiÃÂ ³ n. By comparaciÃÂ charges measures instrument GOME (Globaln Ozone Monitoring Experiment), embarked on satÃÂ © lite ERS-2, and results obtained with the 3D model MWC SLIMCAT of U.de Cambridge, has made the first estimaciÃÂ charges of distribuciÃÂ charges of monÃÂ ³ xido bromine in the layer lÃÂmite marina, the free troposphere and the stratosphere, marking the first time that takes place this distribuciÃÂ charges in subtropical latitudes.

Author: MANDADO ALONSO MARCOS.
Year: 2003.
University: VIGO.
Place of defense: FACULTAD DE QUÍMICA.
Place of preparation: FACULTAD DE CIENCIAS.

Summary: Using the theory of atoms in molecules has been studied transferability of the hydroxyl group and methylene groups in linear alcohols primary, secondary and terciarios.Se has analyzed the effect of the change conformacional, the level of calculation and the effect on the distortion of the chain alquílada is the replacement for the role nitrilo.Se has also investigated the effect of molecular size on energy atómica.Se has also investigated the effect of molecular size on atomic energy, finding qu this stems from the dependence between the ratio of virial and size molecular.Tamaño molecular about atomic energy, finding that this stems from the dependence between ociente the virial and size molecular.También was implemented AIM theory in the study of the link higrógeno both intermolecular as intramolecular.Se have found more significant results as the characterization of a new trímero methanol, and the lack of liaison intramolecular in compounds 1,2-dioles. characterization of a new trímero has led to the first assignment Full IR spectrum of methanol in the region OH.Por its part in the study of the link hydrogen as the sole criterion rigorous finding the presence of a critical liaison (BCP) and a bondpath linking atoms giver and aceptor.Se has applied the theory of atoms in molecules in the study of the acid derived from phenol, finding linear relationships between pka and local properties of the density of population and electronics protón.A turn has been completed, through the determination of rates of offshoring burden, inadequate model reosonancia in the justification for the stability of fenolatos.Un study of the antioxidant activity of acidic benzoicos of natural origin has shown the relationship between antioxidant activity and the potential for ionization, his has been found quela electronic distribution of orbital HOMO not justify load variations experienced by atoms after the process ionización.Por past has done a comparison of some of the results obtained with the theory using the method of AIM participation atomic Hirshfeld.Confirmando that traditional ways of representing the redeployment after loading processes protonación and adding hydride ion are incorrect and that the model of resonance does not justify changing loads experienced in atomic molecules with delocalización load.

Author: CEREZO BUENO CAROLINA.
Year: 2003.
University: COMPLUTENSE DE MADRID.
Place of defense: FACULTAD DE CIENCIAS FÍSICAS.
Place of preparation: INSTITUTO DE QUÍMICA FÍSICA ROCASOLANO C.S.I.C.

Summary: TARGET Study deactivation colisional and transfer of rotational energy of the excited states in radical metilideno. METHODOLOGY The experimental method followed analyzes the emitted fluorescence from a distribution of rotational levels in the metilideno excited formed in the fotólisis of the parent molecule. To study the rotational energy transfer is registered with the emission spectral and temporal resolution of radical metilideno excited in the presence of different pressures Ar. Data provided by the previous experimental findings are discussed with a kinetic model in order to determine the rotational constants of relaxation. To study the deactivation electróica is isolated spectrally emission from a level rovibrónico selected and analyzed by the method of Stern-Volmer, traces temporary registered at different pressures desactivador to obtain constant speed. The experiments have been performed using deactivation Ar excess in order to separate the contribution due to the rotational relaxation. RESULTS The constant rotational relaxation of radical metilideno deuterado in the state A2 * collision with Ar can be represented by a law with the exponential leap in power (where the rotational constants of relaxation from the level of departure Neither the final level vary exponentially with Nf the amount of energy exchanged in the process of relaxation). Sections effective electronic deactivation of radical metilideno in the state A2 * show a reliance on rotational excitation different for each of the three desactivdores considered (CO Xe and H2): in the case of CO decreases slowly with increasing rotational energy and in the case of H2 remain constant for low rotational levels within the range of error, after rising by increasing rotational energy to the deactivation by Xe shows a complex behavior since it increases with eln úmero rotational energy levels for the lower in 1000 cm-1 and decreases for high rotational levels. The species protonada and deuterada behave in a similar manner. The trend observed in the case of CO would be compatible with a model based on forces attractive anisótropas far-reaching. This model does not reflect the behavior in the case of H2, indicating the presence of a barrier in the potential energy surface.

Author: TOERRE-ENCISO HERNANZ MARTA.
Year: 2003.
University: COMPLUTENSE DE MADRID.
Place of defense: FACULTAD DE FARMACIA.
Place of preparation: FACULTAD DE FARMACIA DE LA UCM.

Summary: The theoretical and experimental work done, it has been initially based on the assumption that conventional -formados by phospholipid liposomes high temperature transition fase- not cross the "estratum corneum of the skin, a situation that needed to reach the active ingredients or well bloodstream or the lining of the dermis. To remedy the problem, which is currently being designed other types of vesicles; called elastic -compuesta of phospholipid vesicles with a chain alifática insaturada- or liposomes ultradeformables -compuestos by mixtures of phospholipids with surface active agents. In the first phase of this work, have been prepared and characterized vesicles elastic and you have determined the properties mecano-elásticas of bicapas lipid parameters through: Young module, module comprensabilidad and elasticity. A subsequent study has been the preparation of liposomes ultradeformables, calculating the relationship in which coexist bicapas mixed and subsequent physical characterization of these systems. To comprobrar the provision skin of these systems has been carried out a study of diffusion in vitro via mouse skin with an active ingredient -aciclovir- commonly used in diseases like Herpex, which exerts its action pharmacology at baseline in the dermis. To carry it out, it has become a comparative study between preparations in the previous studies showed greater stability and good physical properties mecano-elásticas, and has been compared to conventional liposomes and a commercial formulation of the active ingredient. From the results obtained, it has been able to verify the hypothesis heading, liposomes ultradeformables show a greater willingness of acyclovir in the dermis.

Author: GARCIA MUÑOZ MERCEDES.
Year: 2003.
University: COMPLUTENSE DE MADRID.
Place of defense: FACULTAD CIENCIAS QUIMICAS.
Place of preparation: FACULTAD CIENCIAS QUIMICAS.

Summary: In the doctoral thesis of this paper have studied the properties interfaciales three systems surfactants. The first of these, a water-soluble ionic surfactant, chloride dodecilamonio (DAC). In this case, it has studied the influence of electrostatic interactions in the topcoat adsorvidas at the interface aire-agua, with a strong dependence of this both the equilibrium and dynamic properties. Secondly, we have studied the topcoat of a material insoluble in water, L-dodecanol, having seen a transition phase liquid -sólido 2D at T = 312 K. Lastly, have studied the properties of balance and dynamics of the topcoat formed by the copolcimeros tribloque type (ethylene oxide) -poli (propylene oxide) -poli (ethylene oxide). Have been studied both in the topcoat Gibbs as the topcoat of Langmuir, obsevándse equivalence between states like surface pressure.

Author: CURUTCHET BARAT CARLES EDUARD.
Year: 2004.
University: BARCELONA.
Place of defense: FACULTAD DE QUÍMICA.
Place of preparation: FACULTAD DE QUÍMICA, UNIVERSIDAD DE BARCELONA.

Summary: The work done on this dissertation focuses on two lines of research aimed at improving the estimation of the theoretical and computational chemistry in the description of the effects of the environment in chemical systems. The first part focuses on the effect of solvent, in particular in developing models of quantum continuous solvatación, and the derivation of models solvatación fractional obtained from continuous methods capable of breaking down free energy transfer between solvatación and solvents contributions associated with fragments of a chemical molecule. This allows to obtain the three-dimensional profile of the regions hydrophobic / hydrophilic of a molecule from its contributions to the fractional solvatación, this being very useful information on building relationships quantitative structure for the development of new drugs, or in the definitions hydrophobic similarity index, based on the similarity of this three-dimensional profile between two compounds. With this goal has been prametrizado satisfactorily the continuing MST model for predicting rates of participation ocatanol / water and energy free solvatación water, cloroforma, carbon tetrachloride and octanol, both ab initio HF/6-31G (d ) as at semiempíricos AM1 and PM3. It has also been MST parameterized model for the study of ionic species in solution. Finally, it has conducted a comparison between the electrostatic response obtained from different models continuous SCRF (MST, SM5.42R and ASM), illustrating the big differences s can be found between the electrostatic and non-electrostatic contributions as model used, and thus demonstrate the close relationship to be considered among these contributions to the solvatación and parameterization of each specific model continuum. The methodology used solvatación fractional has enabled further illustrate the dependence of these contributions fragmentales regarding electronic effects, estérico so tautoméricos. The second part of this work focuses on the development of methodologies for efficient and accurate description of the forces of polarization in camps forces classics. We have studied two methodologies, one based on an implicit treatment of these forces from a double burden model, which allows satisfactorily describe the distribution of burden of a molecule in an isolated environment, and against the action of an external field, respectively, allowing adequately reproduce the energies of polarization for a series of complex bridge hydrogen and catión-pi. It has also been studied including the effects of polarization induced by dipoles punctual. In this regard, it has deepened a methodology capable of obtaining models distributed polarizabilidades atomic isotropic computationally very efficient and allowing reproduce accurately the polarizabilidad overall molecules to the series of derivatives bencénicos studied, as well as the contribution of polarization their energies of interaction catión-pi with a sodium cation.

Author: BAÑUELOS PRIETO JORGE.
Year: 2004.
University: PAÍS VASCO.
Place of defense: FACULTAD DE CIENCIA Y TECNOLOGIA.
Place of preparation: FACULTAD DE CIENCIA Y TECNOLOGIA.

Summary: The recent advance in Photonics has promoted the study of fotofísica new organic dyes. This paper evaluates the properties fotofísicas of pirrometenos to correlacionarlas with its laser characteristics. The study is complemented by the determination of geometric parameters and load distribution system aromatic obtained by calculation mecanocuánticos. We are analyzing the structural and environmental factors that affect the properties of absorption and fluorescence pirrometenos both in liquid solutions as a solid polymer matrices. The primary objective is to find the conditions that optimize the properties laser pirrometenos.

Author: FERNANDEZ SANCHEZ JULIO JUAN.
Year: 2004.
University: POLITÉCNICA DE MADRID.
Place of defense: E.T.S. INGENIEROS TELECOMUNICACION.
Place of preparation: E.T.S. INGENIEROS TELECOMUNICACION.

Summary: This thesis develops the study of two possible photovoltaic materials whose yields are photovoltaic improved by the presence of a band that makes intermediate step between the valence band and driving: Ga4As4Ti and Ga4P3Ti. The study of the two materials is raised and theoretically trying to solve the equation of Schrà ¶ dinger. There are numerous ways to solve the problem here, as each of them carries some other approaches. The thesis was decided to choose the method based on performance criteria and the size of the system to be studied, since they are composed of a large number of atoms. The method chosen was the theory of functional density.

Author: GARCÍA MORAL M. FLOR.
Year: 2004.
University: COMPLUTENSE DE MADRID.
Place of defense: FACULTAD DE CIENCIAS QUÍMICAS.
Place of preparation: INSTITUTO DE QUÍMICA FÍSCIA ROCASOLANO - CSIC.

Summary: The alfa-sarcina is best characterized member from the point of view of the structural and dynamic family of ribotoxinas. Its mode of action is highly specific catalyzing the hydrolysis of a single link fosfodiésteer located in a highly conserved region of the ribosomal subunit's largest RN. Breaking such link inhibit biosynthesis of machinery in the cell and leads to cell death. The basis of the aforementioned specific cytotoxicity and are still not well enlightened. The study of the thermodynamic stability of cytotoxin, and the electrostatic energy from its core asset addressed in this report, are required to contribute to a better understanding of these processes. The studies raised require a structure 3D highly refined, it is part of the structure as determined by high-resolution NMR refined with residual dipolar coupling measured in vectors NH amídicos in half magnetically targeted. An analysis of various procedures for the incorporation of these new restrictions in the calculation of structures reveals that the conditions may be more favorable for refinement. The characterization of the active electrostatic cytotoxin addresses from far pKa values by nuclear magnetic resonance 1H in various mutants isolated (H50Q, E96Q, H137Q, H50/137Q) designed to eliminate one or more charges. The experimental results are compared with theoretical calculations which, based on the structure 3D, interpreting the data in terms of the combination of interactions affecting individual waste, and reveal that the interactions carga-carga play an important role in the modulation the pKa values of the catalytic residues. The pilot thermal denaturation and theoretical calculations based on a model that uses electrostatic the pKa values, have helped analyze the dependence of the stability of the alfa-sarcina and its mutants as a function of pH, and identify waste and interactions specific contributing positively to the stability. The actions of proton exchange 1H/2H of NH providing additional information concerning the skeleton plipeptídico. Finally, it determines the three-dimensional structure in solution of n mutant disposal (14 residues) in the most N-terminal end, absent in the ribonucleasas not cytotoxic. The new biological properties of the mutant is a solid foundation in their new dynamic properties and reorganizations locally detected. The models coupling with the crystalline structure of the ribosome allow propose that this fragment removed could contact ribosomal proteins and essential to be specific recognition of the ribosome by the ribotoxinas.

Author: CANO VAQUERO ANDRES.
Year: 2004.
University: AUTÓNOMA DE MADRID.
Place of defense: DEPARTAMENTO DE FISICA DE LA MATERIA CONDENSADA.
Place of preparation: DEPARTAMENTO DE FISICA DE LA MATERIA CONDENSADA.

Summary: Introduction and main resultádnos Low temperatures and near a transition phase of the second order, they represent two regions in which a. Ideal system should show a universal behavior, namely conduct involving a limited number of degrees of freedom, and that share similar systems. These degrees of freedom normally associated with the described properties scales grandes.footnote (As an example we have the law of Debye for the specific heat at low temperatures, which law is derived from the fonones acoustic wave vectors with smaller.) Therefore, the use of a theory half continued in the regions of universality above this fully justified. The real systems, however, have defects. If it is possible to formulate a theory similar to one that describes systems ideals, and if 1.0 is, what are their characteristics genuine, Guales are their limits of applicability, etc.. Is today a topic of research in which it invests a great effort. That argument can be understood as a contribution to this activity. Contribution focuses on the study of the influence of defects on structural phase transitions, interactions between solitons (or topological defects) mediated deformation fields, and the influence of defects in the properties of real systems at low temperaturas.Se may follow different procedures, but we have tried to exploit the applicability of the theory, half continued in the limit in which the system has no flaws, this is the tactic that followed, for example, to study the Helium superfluido and superconductors, and its success is widely recognized for some time. In fact, in these cases, this tactic has no rival. It is virtually the only way to study, for example, the properties of the respective states of vortices (ie phases containing topological defects) and the "pinning" of vortices which leads to dissipation in transit superconductors (phenomena involve impurities), This tactic will be shown "successful also in dealing with problems that are studied in this thesis. also fits into a context whose concepts and techniques are such that it is relatively easy to make analogies between different problems, Initially, unrelated to each other. Over the thesis we will see a few of these analogies, Major resultactosA then outlines the main findings of the thesis that, later, will be deducted in self chapters. defects and structural phase transitions (Part I) Phase Transitions in two-dimensional systems: Sn / Ge (111) and Pb / Ge (111) In chapter ef (T _C2) presents a phenomenological study of the phase transitions of $ (sqrt (3) imes sqrt (3)) $ R30 $ ") (circ leftrightarrow (3 imes 3) $ taking place in the interfaces Pb / Ge (111) and Sn / Ge (111). The Landau theory is the starting point of this study. The critical behavior that (theoretically) is expected in these areas, and the corresponding influence of defects are discussed in detail. Arguments symmetry show that, contrary to what is generally assumed, emph (behavior of these critical areas are essentially different). The theory of Landau serves as a basis for analyzing the influence of defects in a consistent and large, as well as for ínterpretar experimental data in the literature. In the case of Sn / Ge (111), he pays special attention to the influence of "hopping defects." Among other results is obtained that this influence is such that emph (length correlation may not present any anomaly at the point of transition.) Defects and continuity of almost all transitions phase N-ICCasi all transitions normal-inconmensurable (N-IC) to be observed experimentally are continuous. However, as we shall see in Chapter ef (T C3), in a perfect crystal there is no theoretical reason for the 8 gives this 1ba1 overall performance. A transition phase N-IC will not be too far from the so-called "mean-field tricritical point" should be discoiitinua, and it is highly unlikely that absolutely all transitions N-IC shown experimentally do not meet this requirement. To understand what happens experimentally "in Chapter ef (T _C3) explores the influence of defects on a transition phase N-IC that, in an ideal crystal, it would be of the first order. Influence This is radically different from that normally it is for other tran.siciones first order. Varying discontinuity parameter orders negative and formally diverges within our theory rough. this happens and with a decrease finitá the temperature of the transition. These results interpreted as an indication that at least some of the emph (transitions phase N-IC, which aparentemerite are second order in the experiments are transition is first order in the absence of defects). interaction mediated by the topological defects elasticity (Part II) Vórtices in type II superconductors in chapter ef ~ C5) T (sp c alcula the emph (contribution to the network of energy vortexes that comes from the deformations induced by these vortices, calculation that lieva out for the entire region of magnetic field that defines the state mixed. co); nparación with previous results shows that in most of this joint statement, that contribution has been significantly underestimated so far; The assumption that only "cores" of vortices cause deformation is what gives rise to such understatement. Actually, all variations of space, producing deformation parameter order. True. "cores" regions are important because they parameter disorder can vary greatly. regions But that does not constitute the "core," in which prodúceen variations more gentle parameter, order, can be even more important if they are extensive enough. turns out that in superconductors in which the parameter kappa $ $ Ginzburg is large, where "non-core regions" are actually very extensive, emph (the greatest contribution to the interaction between vortices mediated elasticity comes these "non-core regions . ") Walls dominioEn chapter ef (T C4) is shown that, in three-dimensional solids, there is a emph (universal mechanism of attraction between solitons long-range) and therefore discontinuity of any transition phase conmensurable-inconmensurable ( C-IC). This mechanism is due to the emph (dependence on autoenergía of solitons with deformities and emph () specific features of the elasticity of the solid state.) This mechanism is studied in detail considering a class C transitions CI where the modulation is immeasurable dimensional, anisotropia in the order parameter space is small, and the symmetry of the systems allows for the existence of invariant Lifshitz. In this case, there are two other mechanisms attraction between solitons, but the universal mechanism that is considered in chapter ef (T _C4) becomes more important in circumstances determined. estimates conducted for the transition C-IC which takes place at $ m] K_2SeO- $ 4, probably Transition C - IC studied in more detail in literatúra show that. thermal anomalies observed experimentally know can be interpreted as the result of "smearing" of this transition that, in theory, should be discontínuaDefectos and properties at low temperatures (Part III) Specific Heat of real crystals at low temperaturasEn chapter ef (T _C6) indicates that the properties of glassy crystalline systems need not necessarily be associated with localized excitation (() almost localized). real crystals, the presence of defects ago much as optical vibration acoustic wavelengths short amortiguen, even at zero temperature. If this buffer is independent of the frequency, what happens for example in the case of defects "planar" or defects, loaded, these emph (optical vibration and acoustic wavelengths shorter provide a contríbuéión the specific heat of the corresponding crystalline network, to temperatures sufficiently low, it is linear in T $ $.) temperatures suficieptemente casualties therefore, this contribution will be most imp:> ; rtante that of the acoustic vibrations of wavelengths long (Debye contribution). These two contributions are found to be in the same order at a temperature T propto sqrt $ $ N, where N $ $ is the concentration of defects giving rise to buffer. Estimates show that this temperature is observable. Chapter ef (T_C6) also proposes an explanation for the anomalies of vitreo type that are seen in the specific heat of immeasurable phases at low temperatures. This explanation is based on adequately consider the buffer "fasones" when calculating the thermodynamic quantities, and is presented in three possible scenarios: an fason without gap, a gap static and dynamic gap of origin. data and nuclear magnetic resonance inelastic scattering indicate that these three scenarios are appropriate for biphenyl, blue bronze K_ $ m (O.30) MoO_3 $ and acps respectively. estimates for specific heat at low temperatures reasonably consistent with the experiments. Phase Transitions structural casualties temperatures in the chapter ef (T_C7) is carrying out a desk study of transitions deJase structural low temperatures in considering, emph (both dynamic parameter order type fonónico as dynamic relaxation rate). Whilst the first case limit has been studied previously by other authors, the second is studied here emph (first). Particular attention he pays to conduct asintóticó at low temperatures ae susceptibility widespread. For relaxation, this susceptibi [ity varies $ sim (P2-T_cA2) (-1) $ for times of relaxation independent of temperature in a wide region of diagram phases temperatura-presión. Contrary to what is obtained in the case fonónico, interactions long-range forces such as dipolar, piezoelectric effect, and so on. do not change dramatically this behavior.

Author: COCINERO PÉREZ EMILIO JOSÉ.
Year: 2005.
University: VALLADOLID.
Place of defense: CASA DEL ESTUDIANTE.
Place of preparation: UNIVERSIDAD DE VALLADOLID.

Summary: The research reported in this Doctoral thesis focuses on the study of the composition, structure and properties of alpha-aminoácidos isolated molecular gas phase. It has used a new technique espectroscópica developed in our group that combines laser ablation with microwave spectroscopy with Fourier transformation in supersonic jet (LA-MB-FTMW). The results demonstrate the dominant role of liaison hydrogen in stabilizing the preferred conformations of alpha-aminoácidos. The investigation confirmed that in the immediate future it will be possible to study the gas phase in a wide range of molecules of biological interest through LA-MB-FTMW (amino acids, neurotransmitters, nitrogenous bases, etc.) providing relevant information about its structural properties.

Author: FERNÁNDEZ RUIZ-GAVILÁN DAVID.
Year: 2005.
University: MÁLAGA.
Place of defense: FACULTAD DE CIENCIAS.
Place of preparation: FACULTAD DE CIENCIAS.

Summary: The main aim of the thesis was to show that the spectra SERs can be studied using the same theoretical methods that are used in other problems quimicofísicos. It has been shown that the mechanism for charge transfer is a very important contribution in SERS and in the case of aromatic molecules, it becomes who determines the relative intensities. The analysis methodology developed allows quantitative explanation of most of the experimental facts observed even small details of the spectra recorded. Metal has been included in the ab initio calculations used to obtain frequencies and intensities of the bands SERS, which has enhanced the capacity of analysis in several ways, for example, has been able to quantitatively explain the emergence of gangs and prohibited Raman appear in SERS, without any prior assumptions about the symmetry in the operational environment of the molecule is absorbed. It has been demonstrated that there is no guidance with respect to the surface the factor which determines the intensity of a band, but the effect of charge transfer, which is a major innovation that makes absoletas all interpretations based on the old rules selection of electromagnetic mechanism. Finally, it has become clear that the mechanism is completely fotobnico but involving intermediate steps heat, it is not radioactive.

Author: QUEZADA ALVAREZ MEDARDO ALBERTO.
Year: 2005.
University: COMPLUTENSE DE MADRID.
Place of defense: FACULTAD DE CIENCIAS QUÍMICAS.
Place of preparation: FAC. CIENCIAS QUÍMICAS.

Summary: In this research it was a screening of 416 microorganisms from different taxonomic groups (bacteria, yeasts, filamentous fungi and actinomycetes) in search of new cepasactivaas to oxidation esteroselectiva of secondary alcohols and reduction stereoselective compounds carbonilicos not showing secondary reactions . It was noted that the yeast showed an improved performance compared to the oxidation of alcohols and filamentous fungi to reducing compounds carbonilicos. The yeasts were selected: Pachysolen tannophilus Williopsis saturnus, Williopsis californica. His cell growth was followed by increase in absorbance at 660 nm watching their behavior at different stages of it. The mushrooms were selected; Monascus kaoliang and Diplogelasinospora grovesii; continued its growth by increasing the dry weight of his cell mass. In response pattern was taken oxidation cyclohexanol to cyclohexanone. All strains were stranded in various media such as agar, agarose, polyacrylamide, polyurethane foam, resin lewatit, etc.., Still the best medium for yeast agar special deterocladia A27/03 to 2.5% w / v for filamentous fungi polyurethane foams Isopropanol as co-sustrato being reused many times in batch conditions. Kinetic studies showed that the processes follow a pseudo first-order kinetics and determined the kinetic constants of disabling biocatalizador. Finally, we tested different substrates as ciclopentanol - ciclopentanona; cicloheptanol -cicloheptanona, ciclooctanol - ciclooctanonta, R-furiletanol - S-furiletanol - 2-acetilfurano, Mentona - Menthol, S-carvona - Carveol - Dihidrocarvona, Adamantanona - Adamantanol, 2-decalona - 2-decalol, etc. to assess the estereoselectividad of biocatalizador.

Author: HILLES HANI.
Year: 2005.
University: COMPLUTENSE DE MADRID.
Place of defense: FACULTAD DE CIENCIAS QUIMICAS.
Place of preparation: FACULTAD DE CIENCIAS QUÍMICAS, UNIVERSIDAD COMPLUTENSE.

Summary: This thesis has been carried out extensive research on him rheological behavior of insoluble polymer films at the interface aire-agua. The work can be divided into two big blocs. The study of the dynamic behavior of macromolecular chains in the interface, and the study of the transition from behavior vitreous fluid behavior in the topcoat. The first part has been studied with the concentration dependence, T, and the size of the chain, N of the dynamic relaxation terminal flexible polymers, analyzing the validity of the laws T6 and N3 of reptación in cuasi-2D. In these systems has been studied flow produced in response to an external effort, we found that the initial relaxation, controlled by the reptación, was followed by a steady flow in which there are effects of shear thickening. Finally, in this part have studied the relationship is fuerzo-deformación in two-dimensional gels entrecruzados. In the second part, devoted to the study of behavior vitreous in cuasi-2D, a study has been made dilatométrico of isobars cooling of a polymeric film packaged, obteniéndose coefficients of thermal expansion have been revealed in the dynamic effects cooperative near the transition packaging and the unit has been studied with the surface density and the temperature of the surface shear viscosity.

Author: DÍEZ PASCUAL ANA MARÍA.
Year: 2005.
University: COMPLUTENSE DE MADRID.
Place of defense: FACULTAD DE CIENCIAS QUÍMICAS.
Place of preparation: FACULTAD DE CIENCIAS QUÍMICAS DE LA UNIVERSIDAD COMPLUTENSE.

Summary: It has studied the adsorption surface relative liquid binary mixtures of organic compounds that have no links hydrogen from measures of surface tension and compressibility values determined by osmotic light transmission; values obtained have confirmed that all of them a preferential adsorption occurs at the interface of the component lower tenisón surface. The results have been compared with the predictions of theoretical models of contribution groups Check predictions of these models are rather poor. SE has studied the behavior surface, wide range of composition of a binary system alcoholic hydrogen bond, and the results were contrasted with the prediciones a theoretical model of network that takes this type of interactions intermoleculares. There has been the dynamic characterization of binary systems polimero-agua, where it is a polymer surfactant. Curves tenisón reveal the nature biomodal process of adsorption, with a first phase of very rapid diffusion of molecules to the surface and the second phase of reorganization of the same at the interface. The more concentrated solutions achieve balance in short time, while in the more diluted the balanced interface requires very long periods, even days. The experiments have shown that the isotherms of Gibbs and the Langmur are equivalent in the range of concentrations diluted. It has conducted a survey to determine the rheological properties viscoelasticas adjust values with the molding LVT, which reproduces the behavior of properly modulus of elasticity. The final part has been directed toward the study of the properties termofísicas mixtures in the vicinity of a critical point, analyzing system micelar cationic. It has been necessary to obtain highly accurate measures of health coexisting phases at different temperatures, which has allowed the interval verify validity of the laws of simple scale and critical exponents depending on the model Ising 3D. The analysis of the phases in a mixture has been made, based on the laws of scale, depending on the parameter of order and the diameter of the curve coexistence. To complete knowledge of this system has been measured variation with temperature as tensions surface líquido-aire of solutions homogeneous composition criticism, and the two branches of the curve coexistence, analyzing the results to verify the validity of relations universal amplitudes criticism. Experimental data satisfactorily verified equations established by Widom, introducing the second term development serial Wegner.

Author: CONDEZO HOYOS LUIS ALBERTO.
Year: 2005.
University: COMPLUTENSE DE MADRID.
Place of defense: FACULTAD DE CIENCIAS QUÍMICAS.
Place of preparation: FACULTD DE CIENCIAS QUÍMICAS.

Summary: In this Doctoral Thesis we are finding new bacteria selective for the synthesis of pro-nucleoside exchange basis, develop a synthesis process in a step towards a more sustainable evaluate the possibility of intracellular enzymes to isolate and immobilize the whole cell to be able to reuse the biocatalizador. The primary and secondary screening and implementation of final selection criteria, such as operational stability, bacterial growth, reduction of secondary reactions and maximum value of productivity, allowed select a limited number of bacteria: B.atrophaeus and X. Translucens little active in the ADA and E.amnigenus and B.subtillis, very active in the ADA. Bacteria selected were used in the study of the influence of some variables in the synthesis such as potassium ion concentration, temperature, nature's buffer used as a means of reaction, ion concentration of phosphate, induction of nucleoside fosforilasas, molar relation m substrate and kinetics of the reaction. The B.atrophaeus can make the reaction of synthesis to 45 ° 1C with minimal training of secondary products. The nucleoside increase productivity by adding HEPES to the reaction medium, except in the case of E.amnigenus,. It reached induce expressed nucleoside fosforlasas in E. Amnigenus and B.subtilis, and the biosynthesis of adenosine, in the case of E.amnigenus, B.subtilis and X.translucens, can be accomplished in 20 minutes. The B.atrophaeus can ctalizar synthesis beta-D-arabinofuranosil-adenina (Ara-A), X.translucens the 2-fluor-2'desoxiuridina and beta-D-arabinofuranosil-adenina and E.amnigenus and the B.subtilis the nucleoside 2,6-diaminopurina, with conversions of 100% and 40% respectively. The E. Amnigenus and B.subtilis can be reused in a free in the synthesis of adenosine for 31 to 32 cycles and when immobilized by entrapment in dirogeles of aagarosa, reacicón of biosynthesis was controlled pot ls mass transfer intraparticular. It secuenció PNP's B.atrophaeus; also amplifico the gene coding for the PNP's B.creus ATCC 10987.

Author: MARTÍNEZ HEDO SONIA.
Year: 2005.
University: COMPLUTENSE DE MADRID.
Place of defense: FACULTAD DE CIENCIAS QUÍMICAS.
Place of preparation: FACULTAD DE CIENCIAS QUÍMICAS.

Summary: The efficient synthesis of copolymers etileno-estireno was carried out in recent years, thanks to the use of homogeneous catalysts. Through these materials available cover a wide range of properties ranging from for the polyethylene, semi-crystalline thermoplastic material with a glass transition temperature very low, at the poliesterieno, rigid thermoplastic material with a high glass transition temperature. These properties are dependent on the chemical composition of the copolymer, its structure and the arrangement estereoquímica of styrene in the polymeric chain. In this sense, the choice of catalyst is a factor of particular relevance in the polymerization reaction. Moreover, thanks to the development of computational chemistry, has been able to carry out theoretical studies relating to the mechanism of polymerization. In most of these studies, the employee is ethylene monomer and as representing the kind of active catalyst is taken cationic species cation or "naked". However, in the middle of this reaction is always another species known as cocatalizador that can significantly influence the process of polymerization, as well as the final characteristics of the polymer. In memory of this thesis used various methods of computational chemistry to study the process of copolymerization of etileno-estireno using different homogeneous catalysts. Despite the large number of published studies in both experimental literature concerning this copolymerization, as putacinales concerning the polymerization of ethylene, this thesis represents the first example of a computational study to try to clarify some of the theoretical aspects of the copolymerization of etileno-estireno. We have studied catalyst type monociclopentadienilo based titanium catalyst type ansa-metaloceno with ligands tetrahidroindenilos based on titanium and zirconium with catalysts and ligands moniciclopentadienil-amido based on titanium, known as catalysts geometry forced. They are frequently used to obtain such copolymers. It has taken the cationic species as representing the kind of active catalyst and emphasis has been placed on assessing the activity of the catalyst and the incorporation of styrene in the copolymer. For the catalyst type monociclopentadienilo proposes the existence of two different species: Ti (IV) and Ti (III) in the middle of reacicón. The first of these would be responsible for the synthesis of copolymer, while the other would produce styrene homopolymer, mainly. On the other hand, attempts to explain the reduced activity of the catalyst with ligands tetrahidroindenilos based on titanium with respect to the corresponding based xirconio, based on the differences between the two metals. It was also found that the catalyst geometry forced, because of its peculiar geometry, is the one that incorporates much of the styrene copolymer. In general, increasing the content of styrene in food decreases the activity of the catalyst increases and the content of the copolymer styrene. The results were compared with experimental data found in the literature or within our research group found, in most cases, a good agreement between the two. Finally, in order to carry out a more realistic means of reacicón, has included the presence of cocatalizador metilaluminoxano (MAO) in the theoretical model has been evaluated and the influence of this kind of barriers in the insertion of ethylene the catalyst for styrene and geometry forced. It has been found that, for this system, the effect of MAO is to increase the barriers to integration, the influence being very similar for both monomers.