The discoveries and subsequent developments within the field of metamaterials have opened up for novel light-matter interactions towards the engineering of light behavior. The astonishing phenomenon of negative refraction remains challenging to realize for visible frequencies, and non-magnetic gain metamaterials have been proposed towards this end. This thesis pursues this idea by presenting a conceptual framework for which to understand the requirements and possibilities emerging from the causal behavior of the dielectric response. This results in clear and concrete instructions on how the dielectric response must be designed towards negative refraction. These are offered in terms of a novel perspective employing zero- and pole placements in rational functions and analysis of the dielectric function in its complex plane. A number of negative index systems are evaluated including two component media and low gain negative index media. Negative index concepts are introduced to the Electromagnetically Induced Transparency system. A strategy towards design and realization of arbitrary dielectric responses in terms of Krein and Nudel'man causal extrapolation is also presented.

Experimental and simulation studies of nucleic acid transport through nanosized channels, both biological and synthetic, has become a rapidly growing research area over the last decade. While the utilization of the alpha-hemolysin channel as a sequencing device is soon to be realized, other biological nanochannels may hold advantages that are yet unknown. Motivated by this, the first reported molecular dynamics simulations of DNA translocation through a connexon 26 channel were accomplished, for single-strandeed DNA with a length of 24 nucleotides and with a sequence containing only adenine, cytosine, guanine or thymine bases. Transmembrane voltages between 40 mV and 8.4 V were applied for up to ~2 ns, and the minimum voltage needed for translocation was found to be at 2.4 V. Higher voltages led to shorter translocation times in most cases. Non-translocation or slow translocation events were normally the result of a high degree of foldedness at the entrance of the “funnel” region, the narrowest part of the connexon channel. Distinct differences were seen between the bases, in particular through slower translocations for the purines than for the pyrimidines. Comparison with published literature of alpha-hemolysin translocation found that some of the results were on the same order of magnitude for translocation through connexon channels subject to constraints. It was concluded that to characterize the translocation mechanisms, further investigations should be carried out; both by the use of experiments as well as more simulation studies.

Ultrafast pump-probe spectroscopy is a powerful technique for measuring decay times for an optically excited system, e.g. a semiconductor, on the pico- to femtosecond time scale. We present both a classical approach and a quantum mechanical density matrix approach to simulate the pump-probe signal and compare the two. The main features of a typical pump-probe experiment are explained and the "coherent artifact" is accounted for. With a three-level density matrix approach we explain some experimental features from pump-probe studies of gallium arsenide (GaAs). A simple model for simulating pump-probe of semiconductors is introduced, and the relation to the density matrix approach is derived. We also show how the semiconductor model reproduces the main features of experimental data from pump-probe studies of GaAs.

The effect of optical coatings on the longitudinal magneto-optic Kerr effect response from 10 nm thin films of permalloy (Ni84Fe16) has been studied. Enhancement of the magneto-optic Kerr effect signal contrast of a factor 1.76 has been observed for P- polarized incident light on a trilayer configuration of aluminium, magnesium fluoride, and permalloy. A quadrilayer structure where the trilayer is overcoated with zinc sulphide enhances the signal contrast by a factor 4.05 for P-polarized light. The enhancement is also observed for S-polarized light, and is shown to be reproducible using nickel as the magnetic material and gold instead of aluminium.The experimental data are compared to a simplified theoretical model where the electric field components are calculated using a 4 x 4 matrix algorithm. The model is found to be inadequate in predicting the longitudinal magneto-optic Kerr effect response from complex multilayer structures. This is believed to be due to a simplification in the model disregarding the phase factors of the different components reflected off the multilayered samples.

The differential scattering cross section for diffuse scattering of X-rays from thinfilm structures is discussed within the framework of the distorted wave Born ap-proximation (DWBA). In contrast to the standard Born approximation (BA), thedistorted wave approach succeeds in calculating scattering from surfaces near thecritical angle of reflection. The method is particularly useful for studying averagesurface properties.Compromises made in the derivation of the model substantially simplify thefinal expression, but also limit its range of validity, which depends on the surfaceroot mean square roughness &#963; and the momentum transfer between the incidentand scattered X-rays perpendicular to the surface, Qz . The approximation is validso long as (Qz x &#963;) << 1.However, this is also the only regime where it is necessary togo beyond the simpler Born approximation.A computer simulation software based on the DWBA is implemented in Python.The implemented DWBA depends on the fractal dimension of the surface featuresthrough a parameter h (D = 3 &#8722; h) and an in-plane correlation cut off length &#950;.The various effects of changing key model parameters, among them &#950; and h, isdemonstrated. Comparison between experimental data and the DWBA modellooks promising although there are some challenges in relation to determiningthe fractal dimension.Finally, the feasibility of implementing the DWBA model in a multi-parameterfitting algorithm is discussed.

RGD-functionalized and non-functionalized oil-in-water nanoemulsions of approximately 100 nm containing DSPC, PEGylated DSPE, cholesterol and Gd-DTPA-DSA at a molar ratio of 1.1/0.15/1/0.75 were prepared. In vitro uptake and trafficking in HUVECs of the nanoemulsions was characterized using confocal laser scanning microscopy and flow cytometry. The RGD peptide recognizes &amp;#945;v&amp;#946;3 and &amp;#945;v&amp;#946;5 integrin receptors, which play central roles in angiogenesis. Moreover, the &amp;#945;v&amp;#946;3 integrin receptor is overexpressed in the endothelium of angiogenic tumor vasculature. It was found that the RGD-emulsion showed a remarkably high uptake in HUVECs expressing &amp;#945;v&amp;#946;3 integrins compared to its non-conjugated control version. Furthermore, the RGD-emulsion was able to evade the lysosomes at least within the first 3 hours of incubation, while the control-emulsion was not. The uptake of both emulsions was mainly facilitated by caveolae-mediated endocytosis, but also to a lesser extent by clathrin-mediated endocytosis and other un- known mechanisms. It was shown that RGD and control-emulsions were internalized or sorted into distinct vesicles. Both emulsions bypassed the early endosomes, and it was hypothesized that they were mainly trafficked to caveosomes before subsequent traffick- ing of control-emulsion to late endosomes/lysosomes and of RGD-emulsion to cis-Golgi or endoplasmatic reticulum. The results suggest that the RGD-emulsion has promising feasibility as a site-specific targetable delivery system.

An increasingly important part of food technology is nanotechnology. Inorganic nanoparticles are added directly or indirectly to food in order to create new tastes, appetizing looks or to preserve it longer. Exposure to these nanoparticles is fairly unknown, and there is a need to evaluate the dose that humans are exposed to. In this master thesis, two inorganic substances have been chosen. The first one is silver nanoparticles, commonly known as an antimicrobial agent and added to plastic food containers to preserve food. The second is the food colour E171, titanium dioxide. This is not defined as a nanoparticle because of an average particle size of 200-300 nm, but it is assumed that the size distribution may include nanoparticles. In both cases the intention has been to create an exposure model. For silver, experiments were performed to evaluate the leaching from the food containers to food simulant. The experiments show that first time use of the plastic container will give a concentration in the food simulant of up to a total of 30 ng Ag/g. However, after some use the concentration will be lower than 1 ng Ag/g. The silver experiments show that usage of silver doped food containers will not result in an increase in silver exposure and in general the food containers will not have the claimed antimicrobial effect. However, disposable packaging containing silver may be of concern as the dose of silver leaching from this may be larger.Titanium dioxide data is based on a literature review. Analysis of an E171 sample, showed that up to 50 % of the particles were nanoparticles with a size smaller than 100 nm. Modeling of the exposure to titanium dioxide (TiO2) shows that exposure is diet dependent with an average of 1-3 mg/day/kgbw. The modeling shows that children consume a larger dose than adults, and are more exposed to dietary products containing TiO2. For TiO2 the average dose is larger than the background of 5 mg/day, but lack of an effect threshold makes it difficult to conclude whether this is a unsafe or safe dose.Exposure to inorganic nanoparticles through food will be very dependent on the way of distribution. If added to consumer products the exposure is likely to be less than nanoparticles added directly to the food. Some of the results in this project have been unexpected, like the lack of silver leaching from the plastic containers and a large fraction of nanoparticles in E171. The project only includes two substances and further research into human exposure to other inorganic materials is recommended.

In nanoparticle research it is common to perform optical measurements on particle films during deposition, to help understand the growth process. GranFilm is a software under development which can calculate the optical properties of an array of truncated nanoparticles supported on a substrate. The theory behind these calculations is based on the work of Bedeaux and Vlieger. One feature which was missing from the software until now was the ability to do such simulations on the case of truncated spheroidal nanoparticles with an arbitrary number of coatings of different materials. In the beginning of this work, the equations needed to perform these simulations are derived, and then reduced to previously derived special cases for verification. The new equations are then implemented into GranFilm, and the new code is put through numerical tests. Finally, the new functionality is tested with the help of experimental data from an oxidation process of a silver nanoparticle film. The qualitative evolution of the optical properties of the film is reproduced quite successfully, but some issues remain.

With the prospect of producing superhydrophobic and mechanically stable biomimetic surfaces, the water repellent properties of springtail cuticles are investigated quantitatively. The analysis is based on apparent contact angle measurements on nine springtail species and SEM and AFM images of their cuticles. It is argued that water exists in a metastable Cassie-Baxter state on the cuticle and that three-phase line tension of the order of 10^-8 J/m contributes to high apparent contact angles. A model is developed to assess the significance of a recently reported re-entrant geometry of the cuticle granules and to study the resistance of the cuticle against wetting. The model estimates that springtails resist wetting under hydrostatic pressures up to 10^4 - 10^5 Pa, and that re-entrant granule profiles increase the wetting resistance by 50 - 400%. To explain the low contact angle hysteresis observed on the cuticles, new equations are proposed to include the effect of three-phase line tension. Again, a line tension magnitude of the order of 10^-8 J/m can account for the experimental findings. This work indicates that the sub-micron size scale of the springtail cuticle granules provides an elegant approach for achieving water repellent and mechanically stable surfaces. Two springtail species are singled out as especially promising for biomimetic applications.

This project aims at the fabrication of a rough polydimethylsiloxane(PDMS) surface with patterned smooth areas. The idea is that such a surface will allow for water capturing on the smooth areas of the surface. The applications for this kind of surface are many, but especially the prospects of a surface able to trap droplets of cells in suspension by simply dipping the surface into the suspension is intriguing.From a previous project[1], and another student&#146;s master&#146;s thesis[2], the use of an etched copper surface seemed promising for the fabrication of a rough mold. This was abandoned after sandpaper turned out to be an even better mold, giving superhydrophobic PDMS(162, 33 &#177; 1, 40degrees).The negative photoresist SU-8 5 was used to pattern the sandpaper with small, circular features on the P1000 sandpaper(400&amp;#956;m and 1mm in diameter). The PDMS replica from this mold was a rough surface with smooth wells. This was not able to capture water droplets effectively, partly because air bubbles were trapped in the wells during the immersion in water. To avoid this, another mold was procured by the silanization of the previously made PDMS surface. The PDMS replica of the silanized PDMS had smooth pillars instead of wells, and did not succeed in trapping water droplets either. In fact, the smooth wells seemed to better at capturing the water.This project has succeeded in producing high enough roughness on PDMS to alter the contact angle with water by &amp;#8764; 61 degrees to a contact angle exceeding the lower limit for superhydrophobic surfaces by &amp;#8764; 12 degrees. The use of a sandpaper mold has proven to is simple, inexpensive and effective at producing PDMS with high contact angles.