The late stages of evolution of stars like our Sun are dominated by several episodes of violent mass loss. Space based observations of the resulting objects, known as Planetary Nebulae, show a... Show moreThe late stages of evolution of stars like our Sun are dominated by several episodes of violent mass loss. Space based observations of the resulting objects, known as Planetary Nebulae, show a bewildering array of highly symmetric shapes. The interplay between gasdynamics and radiative processes determines the morphological outcome of these objects, and numerical models for astrophysical gasdynamics have to incorporate these effects. This thesis presents new numerical techniques for carrying out high-resolution three-dimensional radiation hydrodynamical simulations. Such calculations require parallelization of computer codes, and the use of state-of-the-art supercomputer technology. Numerical models in the context of the shaping of Planetary Nebulae are presented, providing insight into their origin and fate. Show less
Light harvesting (LH) lies at the basis of photosynthesis, the process in which energy from the sun is stored by a photochemical reaction. The photophysics of light absorption and energy transfer... Show moreLight harvesting (LH) lies at the basis of photosynthesis, the process in which energy from the sun is stored by a photochemical reaction. The photophysics of light absorption and energy transfer is the key to a detailed understanding of the first steps in this process. This thesis describes the investigation of four types of LH systems that are expressed by bacteria, depending on light conditions. All systems have been studied by optical single-particle spectroscopy in order to eliminate the averaging effects that are typical for ensemble measurements. In this way, the spectral details of the individual systems are reveiled, allowing for a better understanding of the photodynamics that are associated with their spatial structures. Show less
This thesis describes a variety of asymmetric cis- and trans-platinum(II) complexes. The major aim of this research has been the design of complexes with high antitumor activity that may overcome... Show moreThis thesis describes a variety of asymmetric cis- and trans-platinum(II) complexes. The major aim of this research has been the design of complexes with high antitumor activity that may overcome cisplatin resistance, and to establish a comparison between complexes with both geometries. These new type of asymmetric platinum complexes contain in all cases the iPram ligand and in addition either aliphatic amines or azole ligands. Furthermore, a strong emphasis on asymmetric trans-Pt(II) complexes with azole ligands is presented in this research. Show less
Inspired by cisplatin, the inorganic drug discovered by Barnett Rosenberg in 1965, the research described in this thesis uses targeting ligands, or ligands varied in a combinatorial fashion, to... Show moreInspired by cisplatin, the inorganic drug discovered by Barnett Rosenberg in 1965, the research described in this thesis uses targeting ligands, or ligands varied in a combinatorial fashion, to find platinum complexes with more specific modes of action. These studies have lead to the development of novel (solid-phase) synthetic methods and to the discovery of several compounds with promising biological properties. Show less
Because of their information storing and processing capabilities, nucleic acids are interesting building blocks for molecular scale computers. Potential applications of such DNA computers range... Show moreBecause of their information storing and processing capabilities, nucleic acids are interesting building blocks for molecular scale computers. Potential applications of such DNA computers range from massively parallel computation to computational gene therapy. In this thesis, several implementations of molecular computations are described, using new algorithms and technologies. Show less
There are many diseases of the central nervous system (CNS), like Parkinson's disease, Alzheimer's disease, depression, schizophrenia, epilepsy, migraine headache, and HIV infection in the brain.... Show moreThere are many diseases of the central nervous system (CNS), like Parkinson's disease, Alzheimer's disease, depression, schizophrenia, epilepsy, migraine headache, and HIV infection in the brain. However, treatment is difficult since many drugs cannot reach the brain in sufficient quantities due to the existence of the blood-brain barrier (BBB). This barrier is situated at the interface of blood and brain and its primary function is to maintain the homeostasis of the brain. The research described in this thesis was initiated to meet the challenge of drug delivery across the BBB. The focus was to explore the possibilities for drug delivery to the brain via the transferrin receptor (TfR). Although drug delivery to the brain via the TfR is not selective, it is effective. A mechanistic approach was chosen in which the binding and association of Tf, Tf-drug conjugates and Tf-tagged liposomes by BCEC in vitro was determined. The efficiency of delivery depends mainly on the size of the cargo: a 40 kDa protein does not affect the association of Tf by the TfR, while a liposomal drug carrier (100 nm in diameter) affects both the association and the intracellular routing. Show less
