This diploma thesis deals with the preparation and characterization of negatively charged catanionic vesicular systems and their combination with selected polycations. The catanionic vesicular system was prepared by mixing of two oppositely charged surfactants SDS and CTAB. The negative charge as well as the stability of the vesicular system was provided by the incorporation of phosphatidic acid. Polycations, DEAE and TMC, have been selected for use in a pharmaceutical applications. Characterization of the prepared systems was performed by measuring DLS and ELS. The results indicate that we were able to prepare stable negatively charged vesicles that were eligible to non-covalently interact with selected polycations.

A particle counting instrument, the Coherent Optical Particle Spectrometer (COPS) has been developed for measuring particles in aerosol systems. It optically counts and sizes single particles one at a time as they pass through an optically defined inspection region so particle size distributions can be directly measured. COPS uses the coherent nature of light available in a laser beam to measure the phase shift in the scattered light, which is fundamentally different from previous intensity based techniques. The Van-Cittert-Zernike theorem shows that scattered light from small particles will be coherent if viewed upon at the focal point of a gathering lens. Optical homodyne detection can then be used to measure the extent of the phase shift due to the particle. Scattering mechanisms can relate the phase shift to particle diameter so particle size can be determined. An optical inspection region is given by the resolution limited blur spot diameter and depth of focus of the gathering lens. Particles scattering outside this zone will not contribute to measured phase signals. Calculations show that COPS can count in concentrations of 10('9) particles per cubic centimeter with 5% coincidence error. Mie scattering calculations, coupled with homodyne theory, predict a minimum detectable particle diameter ranging from 0.03 to 0.3 micrometers, depending on optical configuration. Theory shows that small, strongly absorbing particles impart a much larger phase shift than refractive particles so a lower detection limit is predicted for particles such as soot and silicon. Particles above one micrometer show classic resonance typical of Mie calculations. An experimental COPS system verified the predicted results from the model. Resolution of particle size ranged from 25 to 60 percent of particle diameter. Preliminary experiments showed that COPS has in situ sampling possibilities and will work for liquid systems as well. Coherent detection of scattered light shows promise for in situ measurement of submicrometer aerosols in high particle laden streams with maximum sensitivity for strongly absorbing particles.

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An investigation is presented into methods of characterising cirrus ice crystals from in-situ light scattering data. A database of scattering patterns from modelled crystals was created using the Ray Tracing with Diffraction on Facets (RTDF) model from the University of Hertfordshire, to which experimental and modelled data was fitted. Experimental data was gathered in the form of scattering patterns from ice analogue crystals with similar optical properties and hexagonal symmetry to ice, yet stable at room temperature. A laboratory rig is described which images scattering patterns from single particles while allowing precise control over the orientation of the particle with respect to the incident beam. Images of scattering patterns were captured and compared to patterns from modelled crystals with similar geometry. Methods for introducing particles en-masse and individually to the Small Ice Detector (SID) instruments are discussed, with particular emphasis on the calibration of the gain of the SID-2 instrument. The variation in gain between detector elements is found to be significant, variable over the life of the detector, and different for different detectors. Fitting was performed by comparison of test scattering patterns (either modelled or experimental) to the reference database. Representation of the two dimensional scattering patterns by asymmetry factor, moment invariants, azimuthal intensity patterns (AIP) and the Fourier transform of the AIP are compared for fitting accuracy. Direct comparison of the AIP is found to be the most accurate method. Increased resolution of the AIP is shown to improve the fitting substantially. Case studies are presented for the fitting of two ice analogue crystals to the modelled database. Fitting accuracy is found to be negatively influenced by small amounts of surface roughness and detail not currently considered by the RTDF model. Fitting of in-situ data gathered by the SID-3 instrument during the HALO 02 campaign at the AIDA cloud chamber in Germany is presented and discussed. Saturation of detector pixels is shown to affect pattern fitting. In-flight operation of the instrument involves the variation of gain of the whole detector (as opposed to individual elements) in order to obtain unsaturated images of both large and small particles.

La gélatine est un ingrédient utilisé dans de nombreuses industries et sa solubilité influence beaucoup ses propriétés fonctionnelles. Des défauts de solubilité sont parfois constatés, notamment suite à un stockage de la gélatine en grains à température élevée et humidité importante. Cette perte de solubilité pourrait être due à la présence de molécules de haut poids moléculaire. L'objectif de ce travail est d’apporter des éléments de compréhension sur la perte de solubilité observée dans les solutions de gélatine. L'utilisation d’une technique de Fractionnement par Flux-Force couplée à une diffusion de la lumière Multiangulaire, a mis en évidence la présence d’agrégats de haut poids moléculaires dans les solutions de gélatine (de 9.5 à 30.2.105 g.mol-1). Ces agrégats n’avaient jamais pu être identifiés par les techniques classiques d'exclusion stérique car elles sont souvent éliminées dans le volume d'exclusion des colonnes. La quantité d'agrégats formés ne cesse d'augmenter lors d'un traitement thermique à 75 °C, aboutissant à l'insolubilité de la gélatine. La compréhension du mécanisme à l’origine de cette perte de solubilité montre l'implication de la lysine disponible, dans l'apparition des agrégats. La lysine libre réagissant au cours du traitement thermique provoquerait la formation d'agrégats qui modifient le comportement de la gélatine en solution aqueuse. Les paramètres de caractérisation de l’AFlFFF-MALS permettent de discriminer partiellement des échantillons de gélatine dont les comportements en solubilité sont différents. Rajoutés aux paramètres classiques de caractérisation comme la viscosité à 6.67% et au dosage de la lysine disponible, la discrimination devient parfaite. / Gelatin is an important product for several industries and its solubility dramatically influences its functional properties. The lack of solubility observed in gelatine is supposed to be due to the occurrence of molecules with high molecular weights, especially after heat treatments. In order to be able to predict the gelatin behaviour, a new technique for its analysis has been developed with an Asymmetrical Flow Field-Flow Fractionation (AFlFFF-MALS) coupled to a multiangular light scattering. The AFlFFF-MALS analysis showed high molecular weight fractions in gelatin ranging from 9.5 to 30.2 105 g.mol-1 which has not been shown previously with alternative techniques such as size exclusion chromatography. After heat treatment of dry gelatine in an oven at 75°C, some huge aggregates appeared, of which size and density increased and led to partial insolubilisation of gelatin into water. The mechanism responsible for this phenomenon involved lysine residues which plays a very important role in gelatin properties. Quantification of available lysine in gelatin samples by LC-UV has been developed. Thermal treatment during 8 days led to a decrease of free lysine content whereas, at the same time, the molecular weight of gelatin fractions increased and α helixes formation in solution was strongly affected. Intermolecular cross-links led to high molar mass compounds and limited protein chain unfolding. From an industrial point of view, AFlFFF-MALS analysis can help to discriminate gelatine samples in regard to their solubility. If other parameters are added (6.67 % viscosity and free lysine) the discrimination was perfect.

Today, thin film based devices are found in a wide field of applications. The main reasons are that thin film technology enables access to unique physical properties and possibilities to miniaturize devices. Thin film devices are generally described in terms such as electrical, optical and magnetical properties. However, the lifetime of these devices is often limited by mechanical stresses causing plastic deformation. An effect of the plastic deformation is hillocking where isolated features are created on the film surface. The continual need to improve performance, reduce size as well as cost is pushing thin film structures close to or beyond present fundamental understanding. Further progress requires better understanding of basic phenomena where analytical methods for characterization of thin film deformation play a crucial role. To follow the initial hillock formation during thermal treatments it is essential to have a suitable tool for achieving real-time measurements with high sensitivity over a relatively large area that does not considerably affect the film surface. Methods based on light scattering are generally very sensitive to changes in the surface topography and allow contact free measurements at high speed. In this thesis light scattering methods are investigated as tools for stress analysis of thin metal films. Detection and characterization of isolated surface features using angular resolved scattering has been investigated by simulations. Results were used in development of an optical instrument for simultaneous measurements of initial hillocking and changes in overall film stress. The instrument combines light scattering and laser beam deflection techniques. It is shown how the onset of initial hillocking in aluminum films is accompanied by stress relaxation. Real-time dark field microscopy was demonstrated as a technique for analysis of the lateral hillock distribution. Analysis of the distribution show clustering of hillocks which is supposed to be related to the microstructure of the film. It is demonstrated that copper inclusion can be used to strengthen aluminum films to withstand higher stress before hillocking occurs. The copper content also reduces the grain size and thereby the surface roughness, which results in good or even better optical performance than for pure aluminum films. / <p>NR 20140805</p>

During production of different Hyaluronic acid (HA) products Galderma use a high concentration of NaOH in the crosslinking process of HA. HA’s degradation kinetics are widely unknown at higher pH’s and is interesting for the future of product development of HA. Static Light Scattering (SLS) was used to determine the weight average molecular weight (MW ) of samples with four different NaOH concentrations, four temperatures, three reaction times and one t0  sample. The results were evaluated in forms of Arrhenius-graphs for different NaOH concentrations, the activation energy (EA ) with respect to pH and the reaction rate for each temperature with respect to NaOH concentration. It was found that the degradation of HA was more strongly affected by temperature than by NaOH concentration and that the EA  did not show any significant signs of change between higher concentrations of NaOH.

Purpose: 1) To estimate the threshold dose and the time evolution for cataract induction by near infrared radiation (IRR) in seconds exposure time domain; 2) to determine the ocular temperature development during the threshold exposure; 3) to investigate if near IRR induces cumulative lens damage considering irradiance exposure time reciprocity; 4) to experimentally estimate the temperature in the lens indirectly from the measurement of temperature-induced light scattering increase. Methods: Before exposure, 6-weeks-old albino rats were anesthetized and the pupils of both eyes were dilated. Then the animals were unilaterally exposed to 1090 nm IRR within the pupil area. Temperature was recorded with thermocouples placed in the selected positions of the eye. At the planned post-exposure time, the animal was sacrificed and the lenses were extracted for measurements of forward light scattering and macroscopic imaging (Paper I-III). In Paper IV, the lens was extracted from six-weeks-old albino Sprague-Dawley female rats and put into a temperature-controlled cuvette filled with balanced salt solution. Altogether, 80 lenses were equally divided on four temperature groups, 37, 40, 43 and 46 ºC. Each lens was exposed for 5 minutes to temperature depending on group belonging while the intensity of forward light scattering was recorded. Results: The in vivo exposure to 197 W/cm2 1090 nm IRR required a minimum 8 s for cataract induction. There was approximately 16 h delay between exposure and light scattering development in the lens. The same radiant exposure was found to cause a temperature increase of 10 °C at the limbus and 26 °C close to the retina. The in vivo exposure to 96 W/cm2 1090 nm IRR with exposure time up to 1 h resulted in an average temperature elevation of 7 °C at the limbus with the cornea humidified and no significant light scattering was induced one week after exposure. Arrhenius equation implies that the natural logarithm of the inclination coefficient for light scattering increase is linearly dependent on the inverse of the temperature. The proportionality constant and the intercept, estimated as CI(0.95)s, were 9.6±2.4 x103 K and 22.8±7.7. Further, it implies that if averaging 20 measurements of inclination coefficients in a new experiment at constant heat load, the confidence limits for prediction of temperature correspond to ±1.9 °C. Conclusions: It is indicated that IRR at 1090 nm produces thermal but not cumulatively photochemical cataract, probably by indirect heat conduction from absorption in tissues surrounding the lens. Applying the Arrhenius equation the in vivo temperature in the lens can be determined retrospectively with sufficient resolution.

The objective of this research is to further define the relationship between the charge state of insulin, and the self assembly properties of insulin and PEGylated insulin in solution. Polyethylene glycol (PEG) chains were covalently attached to insulin in order to evaluate their impact on insulin's systemic duration of action after pulmonary dosing. This thesis will focus on the assembly properties of the PEG-insulin and insulin, and also demonstrate how the charge state, which was modified by the covalent attachment of PEG, relates to different modes of behavior by anion and cation exchange chromatography. In addition, explain how modifying the assembly state extends to improving formulation properties of spray-dried insulin powders. This thesis is an investigation into the relationship of insulin's charge state controlled by pH and how the charge state affects the self assembly of insulin, especially when the zinc ion is removed. Ionic interaction is one of the major forces affecting insulin assembly. The theory that a change in the charge state of insulin could modulate the ionic interaction and reduce hexamer formation at alkaline conditions was investigated. Experiments were designed to measure the level of hexamer with light scattering, and the amount of hexamer was then correlated with the pH and zinc content of the solutions. The importance of the charge state of the monomer and its behavior extends to chromatography and purification modes as well. Specifically, the purification of various species of PEGylated insulin presents a challenge. By varying mobile phase pH which induces the charge to insulin, an ion exchange method demonstrated very high resolution and controllable interaction between the ion exchange media and the insulin derivatives. A highly accurate method for determining molecular weight and thus the average associated state of insulin in solution has been developed using the MALS (Multi-Angle Light Scattering). Insulin concentration, pH, and metal ion concentrations, were in pharmaceutically relevant ranges. The MALS method was developed to evaluate how the parameters above affect the self-assembly properties of insulin, and use the assembly properties to improve formulations of insulin or PEGylated insulin. To use the light scattering technique the dn/dc (change in refractive index with change in concentration) is required. During the method development, the dn/dc of insulin was measured at 690 nm, and a value of 0.185 mL/g based on theory was confirmed. A novel approach for preparing insulin powders with improved chemical stability, based on maintaining the dissociation of hexamers in solution during the spray drying process was developed. The mode presented here is to remove the zinc ions from solution, increase the pH from 6.6 to 7.8, and maintain a low concentration of insulin approximately 2 to 15 mg/mL. Each of these factors alone decreases the hexamer population in solution, but by combining all three factors, hexamers are driven to very low levels of equilibrium. The increased stability of the powders is predominately related to the decrease in covalent insulin dimer (CID). The data presented correlates a reduced hexamer population in the solution with lower levels of CID's in the dry powder compared to controls. The CID formation rate was reduced by 40% compared to a control.

This thesis examines the properties of transmission and transport of light and charged particles in periodic or quasiperiodic systems of solid state and optics, especially the nonlinear and external field effects and the dynamic properties of these systems.