BackgroundPost-surgical macular edema (ME) is a common cause of prolonged visual impairment. Here we report on the feasibility and clinical outcomes from the use of a novel suprachoroidal... Show moreBackgroundPost-surgical macular edema (ME) is a common cause of prolonged visual impairment. Here we report on the feasibility and clinical outcomes from the use of a novel suprachoroidal microcatheter to treat post-surgical chronic ME by the posterior suprachoroidal placement of a triamcinolone acetonide (TA) suspension.MethodsTwo patients were catheterized with the Oxulumis suprachoroidal delivery system on two separate occasions starting 5 and 10 mm posterior to the limbus. The catheter only remains in the suprachoroidal space for the time of the drug administration. Visual acuity and spectral domain optical coherence tomography (SD-OCT) changes were followed over several weeks to months to determine the duration of ME resolution.ResultsSuprachoroidal microcatheterization for posterior delivery of triamcinolone was possible in all attempts using the illuminated Oxulumis catheter. No reflux, scleral or choroidal trauma was observed. There was no intraocular pressure rise during the follow-up period. The triamcinolone deposit was visible on infrared imaging and on SD-OCT a choroidal elevation was visible. Both progressively disappeared over time. A rapid resolution of ME associated with improved vision was observed following each injection for 3 to 7 months with a TA dose of 2.4 mg or 4 mg.ConclusionsIn these patients with poorly responsive ME, posterior suprachoroidal TA led to a visible suprachoroidal drug deposit and prolonged visual improvement. The Oxulumis microcatheterization device performed as expected and was not associated with any complications. Show less
Context. A complex environment exists in the inner few astronomical units of planet-forming disks. High-angular-resolution observations play a key role in our understanding of the disk structure... Show moreContext. A complex environment exists in the inner few astronomical units of planet-forming disks. High-angular-resolution observations play a key role in our understanding of the disk structure and the dynamical processes at work.Aims: In this study we aim to characterize the mid-infrared brightness distribution of the inner disk of the young intermediate-mass star HD 163296 from early VLTI/MATISSE observations taken in the L- and N-bands. We put special emphasis on the detection of potential disk asymmetries.Methods: We use simple geometric models to fit the interferometric visibilities and closure phases. Our models include a smoothed ring, a flat disk with an inner cavity, and a 2D Gaussian. The models can account for disk inclination and for azimuthal asymmetries as well. We also perform numerical hydrodynamical simulations of the inner edge of the disk.Results: Our modeling reveals a significant brightness asymmetry in the L-band disk emission. The brightness maximum of the asymmetry is located at the NW part of the disk image, nearly at the position angle of the semimajor axis. The surface brightness ratio in the azimuthal variation is 3.5 ± 0.2. Comparing our result on the location of the asymmetry with other interferometric measurements, we confirm that the morphology of the r < 0.3 au disk region is time-variable. We propose that this asymmetric structure, located in or near the inner rim of the dusty disk, orbits the star. To find the physical origin of the asymmetry, we tested a hypothesis where a vortex is created by Rossby wave instability, and we find that a unique large-scale vortex may be compatible with our data. The half-light radius of the L-band-emitting region is 0.33 ±0.01 au, the inclination is 52°(-7°/+5°), and the position angle is 143° ± 3°. Our models predict that a non-negligible fraction of the L-band disk emission originates inside the dust sublimation radius for μm-sized grains. Refractory grains or large (≳10 μm-sized) grains could be the origin of this emission. N-band observations may also support a lack of small silicate grains in the innermost disk (r ≲ 0.6 au), in agreement with our findings from L-band data. Show less
This thesis is about the study of hydrocarbons via infrared spectroscopy. Hydrocarbons play an important role in the chemistry of a variety of astronomical environments from the diffuse... Show moreThis thesis is about the study of hydrocarbons via infrared spectroscopy. Hydrocarbons play an important role in the chemistry of a variety of astronomical environments from the diffuse interstellar medium to dense hydrocarbon atmospheres of solar system bodies (e.g., planetary atmospheres of Jupiter and Saturn’s moon Titan) and exoplanets. For most astronomical objects, the determination of chemical abundances, and consequently an understanding of the chemical evolution relies upon the observation of molecular spectra. However, to date astronomical models need to make assumptions, because not all of the molecules expected have been observed. This is due, in part, to a lack of accurate spectral data, which is needed for unambiguous identification. Using a combination of high-resolution infrared experiments and/or high level ab initio calculations of vibration frequencies and ground state spectroscopic constants, the infrared spectral data of HC2H, HC4H, HC6H, HC8H, C3H4, c-C3H3+ and Dn-PAHs (polycyclic aromatic hydrocarbons, PAH) are studied and presented, in order to fill in some of the missing spectral data. Show less
Large areas of space are filled by molecular clouds that consist of gas and dust grains that are the remnants of dead stars. When these clouds start collapsing, the decreasing temperature and... Show moreLarge areas of space are filled by molecular clouds that consist of gas and dust grains that are the remnants of dead stars. When these clouds start collapsing, the decreasing temperature and increasing density cause gas particles to start accreting onto dust grain surfaces. This results in layered geometries of partially mixed ices on top of the grains that act as molecule reservoirs and cryogenic catalysts on which both simple and complex molecules form in surface reactions. These grains form the material from which celestial bodies form. A good understanding of the elementary processes taking place in dark interstellar clouds, therefore, is necessary to understand the chemical inventory of stellar systems, like our own Solar system.This thesis focuses on laboratory studies investigating the surface chemistry of CO-rich ices on dust grains at temperatures as low as 10 K. The formation mechanisms of complex organic molecules (COMs) are investigated by non-energetic processes (e.g., hydrogenation) and energetic processes (e.g., photolysis). Moreover, the net transfer of the newly formed hydrogenated species from grain surfaces into the gas phase through non-thermal desorption is investigated to link the detection of COMs in the gas phase to their formation in the solid state. Show less
This thesis presents the anharmonic infrared spectra of a series of polycyclic aromatic hydrocarbons. Comparisons and characterizations are made based on high-resolution low-temperature gas-phase... Show moreThis thesis presents the anharmonic infrared spectra of a series of polycyclic aromatic hydrocarbons. Comparisons and characterizations are made based on high-resolution low-temperature gas-phase experimental spectra. Show less
The thesis "Spinning Worlds" is about the characterisation of two types of gas-giant exoplanets: Hot Jupiters, with orbital periods of fewer than five days, and young, wide-orbit gas giants,... Show moreThe thesis "Spinning Worlds" is about the characterisation of two types of gas-giant exoplanets: Hot Jupiters, with orbital periods of fewer than five days, and young, wide-orbit gas giants, with orbital periods as long as thousands of years. The thesis is based on near-infrared observations of 1 hot Jupiter and 3 wide-orbit gas giants at high spectral resolution. The observing strategies and the analyses are unique for the two types. For the hot Jupiter, HD 209458 b, the focus is the vertical temperature structure of the atmosphere. This particular hot Jupiter was previously thought to have an atmospheric layer where the temperature increases with altitude, but we found evidence against the existence of such a layer. The three wide-orbit gas giants are all in the early stages of their lives, and we measured their rotation and found a correlation with age: The very youngest objects rotate more slowly than the slightly older (20 million years) objects. We interpret this as the initially hot and bloated exoplanets cooling down and contracting, causing them to spin-up, until the contraction slows down as they approach a radius comparable to that of Jupiter. Show less
In this thesis I study in detail the conditions of the interstellar medium of a three starburst galaxies that cover a wide range of metallicities and star formation areas. I have shown a strong... Show moreIn this thesis I study in detail the conditions of the interstellar medium of a three starburst galaxies that cover a wide range of metallicities and star formation areas. I have shown a strong support for efficient destruction of PAH molecules by UV photons in NGC 5253, independently of variations of metallicity. In a more luminous central starburst galaxy such as M82, the radiation field is about 40 times softer than in NGC 5253 with little spatial variation, and the star formation has been strongly suppressed in the last 5 Myr as a result of feedback effects. On scales larger than a few kiloparsecs, large scale events like galaxy interactions become relevant. From studying Arp 143, I found strong support for the scenario in which a radially expanding, large-scale shock wave from a head-on galaxy-galaxy collision has swept up the interstellar medium and triggered the formation of these clusters. Finally, I investigated the properties of the dust emission in starburst environments. A small fraction of galaxies require a very cold component with T<14 K. Most of these "cold" galaxies are mergers and exhibit a high fraction of stochastically heated very small grains (VSGs). Either a large amount of big, very cold silicate grains in the diffuse ISM, or a significantly higher fraction of VSGs. Show less
In this thesis we use the very large telescope interferometer in order to observe dust residing in the nuclei of active galaxies. We compare our observations with the commonly accepted unified... Show moreIn this thesis we use the very large telescope interferometer in order to observe dust residing in the nuclei of active galaxies. We compare our observations with the commonly accepted unified model for active galaxies Show less
The design of novel anticancer agents is one of the most active fields in Medicinal Chemistry, as the number of effective drugs for treatment of cancer is still very limited. This demand for new... Show moreThe design of novel anticancer agents is one of the most active fields in Medicinal Chemistry, as the number of effective drugs for treatment of cancer is still very limited. This demand for new drugs is even higher, considering the high cancer-prevalence rate in our society. The therapeutic application of metal complexes is an under-developed area of research and basic principles in the development of metallopharmaceuticals are lacking, or at least just recently being discovered. Metal-containing agents may offer unique therapeutic opportunities. However, significant obstacles, including potential metal accumulations and toxicities, require further research before a promising metal compound may be introduced in the clinic. In particular several ruthenium and gold coordination compounds have shown promising application as anticancer agents. In these terms, this thesis project, performed in the Coordination and Bioinorganic Chemistry group in the Leiden Institute of Chemistry, comprises the design, synthesis, detailed characterization (i.e. elemental analysis, UV-Vis spectroscopy, IR, far-IR, NMR, mass spectroscopy and X-ray single-crystal structure determination) and also the biological evaluation of novel gold compounds and ruthenium compounds. The promising cytotoxic activity developed for several of these compounds and the findings from this research are providing a better understanding of chemistry of Ru(III) and Ru(II) and Au(III) coordination compounds and their structure-activity relationships and may lead to the development of improved ruthenium and gold-chemotherapeutic drugs. Show less
The thesis describes infrared radiation and dust properties of the Magellanic Clouds, together with comparisons with emission at other wavelength regimes. Observations of the SMC and LMC were made... Show moreThe thesis describes infrared radiation and dust properties of the Magellanic Clouds, together with comparisons with emission at other wavelength regimes. Observations of the SMC and LMC were made with the IRAS satellite. Maps are presented at wavelengths of 12, 25, 60 and 100 _m. From these maps a list of discrete infrared sources is extracted. This source list is compared to known object lists (foreground stars, SMC stars, H_ nebulosities, clusters, supernova remnants, planetary nebula and dark clouds). There is a good correlation between HII regions and infrared emission from the SMC. For the LMC a similar presentation and discussion is given as for the SMC. A list of discrete sources is extracted, which is compared to similar source lists. As for the SMC, there is also a very good correlation of the infrared emission peaks with HII regions in the LMC. The Galactic infrared foreground emission is discussed. Foreground filaments disturb the image of this Cloud, and the IRAS data show significant variations in the foreground. The relation between the infrared foreground emission and the atomic hydrogen content is found to be non-linear. An estimate for the foreground infrared emission is derived, based on the average gas-to-dust ratio. The foreground towards the LMC varies from 0.07 to 0.17 magnitude, with an average of 0.10. A more or less constant foreground of 0.08 magnitude towards the SMC is found. Global properties of the Magellanic Clouds are discussed. Integrated infrared flux densities, infrared sizes, infrared luminosities and dust temperatures are derived. The infrared morphology is discussed, together with the temperature distribution. It turns out that the Greater 30 Doradus Region emits about 40 % of all infrared radiation. The density of the interstellar radiation field in the Clouds is derived. On average the fields are 7 times stronger than the Solar Neighbourhood field. A relation is found between infrared emission and the H_ supergiant shells in the LMC. Comparisons of the infrared maps are presented with ultraviolet data, H_ maps and with radio continuum observations. The SMC is 10 to 20 times weaker than the LMC in the infrared. The thesis describes dust properties in the Magellanic Clouds. The mid-infrared (12 and 25 _m) emission in the Clouds is less than that in the Local Group spiral galaxies. It is most likely that very small grains are responsible for this emission. Dust masses are derived for the combined warm (~50 K) and cool (25 K) dust components. The mass present in the cold (15 K) dust component is estimated to be between 1/3 and 1 times the mass of cool dust. Total dust masses of 550000 solar masses for the LMC and 24000 solar masses for the SMC are derived. Dust column density maps are presented for both Clouds. From a comparison of the infrared maps with atomic hydrogen maps, similar non-linear relations are found as for the Galactic foreground. Global properties of the Clouds are discussed in relation with irregular galaxies and in relation with Local Group spiral galaxies. The infrared colours of the Clouds are similar to the colours of other irregular galaxies. There are some exceptions, NGC 6822 and NGC 1569 have much lower f12 _m/f25 _m ratios than the Clouds, but their f60 _m/f100 _m ratios are similar. The luminosity-to-mass ratio of the SMC is similar to that of other irregular galaxies. That ratio of the LMC is an order of magnitude higher, and is comparable to that of spiral galaxies such as IC 342, M101and M33. Relative to the irregular galaxies, the gas-to-dust ratio in the LMC is low. The LMC gas-to-dust ratio is probably not very different from that in M31 and M33. For the LMC a ratio 3 times higher than for the Milky Way is found; for the SMC the ratio is 50 times higher than for the Milky Way. The LMC value agrees well with that of other authors, based on photometric B and V measurements and Ly_ absorption. The SMC value is, however, 3 to 6 times higher than those ratios. This difference is explained by Galactic foreground difficulties in photometric observations: high foreground extinction values from Chapter IV suggest large variations on small scales for individual stars. A new fit is made to the EB-V and NHI data, showing agreement with the dust mass based on infrared data. These findings also agree with the integrated ratio L100 _m/MHI, which is about 30 times lower for the SMC than for the Galaxy. Show less
