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Metallophilic (metal-metal) interactions are weak interactions between closed-shell (d10, s2) or pseudo-closed-shell (d8) metal cations. This type of interaction is generally believed to be responsible for various intriguing structures, luminescence, catalysis and magnetism. To gain a better understanding of metallophilic interactions, both experimental and computational investigations have been carried out in this thesis. Chapter 1 gave an up-to-date literature review on the definition, significance, and methods of estimating metallophilic interactions. The disputed nature and strength of metallophilic interactions encouraged us to further understand them. Chapter 2 focused on aurophilic interactions between AuI cations. Aurophilic interactions were observed in the solid state, but not well expressed in solution. Further experimental and computational results suggested that the strength of aurophilic interactions were weaker than electrostatic interactions. The nature of aurophilic interactions arose from orbital interactions rather than dispersion. Chapter 3 presented the study of metallophilic interactions between group 10 metal centres, including PtII-PtII, PdII-PdII and NiII-NiII. A series of cyclometalated square-planar metal complexes with different metals or substituents were prepared. PtII-PtII interactions were found to be stronger than PdII-PdII and NiII-NiII interactions. The dimerization constants of the Pt-containing complexes increased in line with increasing electron-withdrawing ability. Chapter 4 investigated the solvent-induced and thermally dependent colour changes of the Pt-containing complexes synthesised in chapter 3. Metallophilic interactions were proposed to be important in influencing the luminescence properties.

Thesis (Ph. D.)--University of Hong Kong, 2007. / Title proper from title frame. Also available in printed format.

The solution structure determination of DNA molecules has been an important part of structural biology. NMR solution structures are a complement to structures solved via X-ray crystallography; the two methods are the only ways of obtaining three dimensional coordinates of macromolecules. Because of the nature of the molecule, the solution structure determination of DNA has been a challenging task. Assignments are the first and most important part of NMR structures, and can be simplified for DNA with the use of the rotating frame Overhauser spectroscopy (ROESY) experiment. The ROESY technique can be used for unambiguous assignments of H2' and H2" protons and for distinguishing the three main forms of DNA duplexes: A-form, B-form and Z-form. Many types of DNA have been examined using NMR spectroscopy, including drug-bound DNA complexes. Most previous studies of complexes of the anti-cancer drug Actinomycin D (ActD) and DNA used self- complementary sequences to identify stabilizing features. The studies presented in this thesis use non-self-complementary DNA hexamers to identify the two orientations in the binding of the asymmetric ActD drug. The largest preference of asymmetric binding was found for the d(CCGCCG)•d(CGGCGG) sequence; however, NMR spectral complications prevented the structure elucidation of this complex. Instead the solution structure was determined for the complex with the next largest orientational preference, ActD:d(CTGCGG)•d(CCGCAG), which has 67% of ActD molecules intercalated with the benzenoid side of ActD in the first strand. The solved structure identifies unusual DNA features, which could be due to the bound drug inducing structural changes to the B-DNA duplex or the presence of conformational motion. For seven of the eight sequences, the orientation of ActD intercalation within the DNA duplex was identified. The largest preference occurs when the benzenoid intercalation site is followed by a guanine. When this guanine is replaced by an inosine, a reduction in the asymmetric binding of ActD is observed, indicating that the guanine NH₂ group plays a role in the intermolecular contacts. Thus, the two orientations of ActD binding are not present in equal concentrations although their structures are similar, and the preference of orientation is influenced by the asymmetric DNA sequence flanking the intercalation site. / Graduation date: 2002

This dissertation examines the interaction of the linker histone with DNA and with nucleosomes. The first goal of the project was to characterize the interaction of the linker histone with DNA. Three factors previously reported to influence the linker histone's interaction with DNA were examined: ratio of linker histone to DNA sites of binding, monovalent ions in the local environment, and conformation of the DNA molecules. Evidence obtained through gel mobility shift assays demonstrates the strong preference by the linker histone for DNA with superhelical torsion, i.e., supercoiling, and the negative cooperative mode of binding that the linker histone exhibits in association with supercoiled DNA. The second part of the dissertation examines the location of linker histone binding on the nucleosome, and documents the pronounced tendency of the linker histone to bind to two DNA duplex strands. A preparation of homogeneous nucleosome core particles, consisting of a defined 238 base pair DNA fragment and the core histone octamer positioned precisely on this DNA, was used as a substrate for the UV-induced crosslinking of the linker histone to the DNA of this nucleosome. By site-specific labeling of a single site on the DNA of the nucleosome, the linker histone was observed crosslinked at that labeled site, confirming that the linker histone binds at the pseudo-dyad axis of the nucleosome. This evidence was used to support a model of linker histone binding to the nucleosome that invokes the association of the linker histone with no fewer than two duplex strands of DNA of the nucleosome. / Graduation date: 2004

In order to better characterize linker histone interactions with DNA, avian erythrocyte-specific linker H5 and the trypsin-resistant globular domain of H5 (GH5) were used in DNA binding studies. To begin, H5 displayed a considerably higher binding affinity for DNA than the isolated globular domain (GH5), supporting the importance of the terminal tail domains in binding. This conclusion is based upon binding curves conducted in low-salt solution, and on the considerably-higher salt concentration required to prevent protein-DNA contact. Linker histones also induce DNA-protein aggregation in a process that was found to result in protein insolubility in 2% SDS, and included protein-protein interactions that did not require the terminal tail domains. In addition, DNA supercoiling appeared to impede the aggregation process; this that may be attributable to binding of linker histones in isolated clusters, as gauged by a limit in the number of observed dithiobis (succinimidyl) propionate (DSP)-crosslinkable contacts. In a related study, the property of GH5 to bind, then organize onto DNA was investigated. GH5 crosslinked onto DNA with dithiobis (succinimidyl propionate), then cleaved with chymotrypsin, displayed highly uniform contacts that appeared to involve the C-terminal four amino acids, and suggests protein-protein interactions are important for binding. This finding may be relevant since GH5 (and H5) were observed to self-associate free in solution in an arguably specific manner. Finally, the exposure of Phe 93 to chymotrypsin was used to identify the surface of the globular domain that contacts DNA for the binding of intact H5. Results suggests that the side of the protein opposite to the recognition helix preferentially binds to DNA, supporting a novel winged-helix protein DNA-binding mechanism. Furthermore, parallel studies with octamers reconstituted onto a DNA fragment with twelve copies of the 208 b.p. rDNA 5s gene from Lytechinus variegatus, shows that H5 had a high binding affinity with all detectable protein binding to the reconstituted complex. H5 binding conferred protection to a site located near the dyad axis from endonuclease digestion, supporting the contention that H5 binds near or at the nucleosome dyad axis. H5 binding also was observed to condense fibers as observed from agarose gel electrophoresis, although velocity analytical sedimentation studies indicate that H5 in itself was not sufficient to fully compact chromatin fibers; rather H5 and 30 mM NaCl, in combination, were required. Results indicate that the chromatin-reconstituted "208-12 DNA" makes an excellent model for analyzing the effect of linker proteins on chromatin morphology. / Graduation date: 1998

Thesis (M.S.)--University of North Carolina at Greensboro, 2006. / Title from PDF title page screen. Advisor: Gregory Raner; submitted to the Dept. of Chemistry. Includes bibliographical references (p. 68-70).

This study examined the relation between attachment characteristics and intimacy experienced after one’s attachment style is activated. Attachment theory states that when an individual feels threatened by an attachment figure, attachment style is activated and dictates how that individual relates to his or her partner in that situation. This study tests this theory. Data were collected on 110 committed romantic couples from the community. Each individual completed a series of questionnaires, including the Adult Attachment Questionnaire. Couples then engaged in a series of four videotaped interactions in which both partners had an opportunity to discuss times in which their feelings were hurt by someone other than their partner and times in which their feelings were hurt by their partner. These interactions were regarded as low- and high-risk, respectively. The high-risk interaction was specifically targeted to activate attachment style and elicit attachment behaviors. Analyses were conducted using the Actor-Partner Interdependence Model (APIM). This model takes into account the interdependence of observations between partners. As a function of this model, both actor effects (the effect one’s own attachment style has on one’s own experiences of intimacy) and partner effects (the effect one’s own attachment style has on one’s partner’s experiences of intimacy) were examined. Intimacy was conceptualized in two different manners: state (post-interaction intimacy) and trait (overall intimacy in the relationship). It was hypothesized that individuals with insecure attachment characteristics would report lower feelings of both state and trait intimacy compared to securely attached individuals. It was also predicted that the partners of individuals with insecure attachment characteristics would report lower state and trait intimacy following the high-risk interaction compared to partners of secure individuals. The results of this study supported these hypotheses. Models testing the effect of the attachment characteristics avoidance, ambivalence, and avoidance-x-ambivalence found a relation between the presence of insecure attachment characteristics and lower levels of both state and trait intimacy. Implications of these results and future directions of study are discussed.

Ce travail consiste en létude de deux échantillons de quasars lumineux et proches. Tout dabord, nous effectuons une étude simultanée de données provenant du Hubble Space Telescope et du Very Large Telescope dans le but détudier dans le détail les caractéristiques des galaxies hôtes de 6 quasars. Un traitement adéquat des données spectrales du VLT et des images du HST, basé sur la méthode de déconvolution MCS, permet de décrire avec une grande précision la structure de la galaxie hôte ainsi que diverses propriétés du système. Ainsi, nous pouvons caractériser linfluence du quasar sur son environnement. Nos analyses prouvent en effet la présence de gaz ionisé par le quasar dans des régions éloignées du centre et apparemment dépourvues détoiles, mais aussi lexistence de zones galactiques réfléchissant le rayonnement du quasar via des électrons libres ou de la poussière. La dynamique du gaz entourant le quasar est analysée via la courbe de rotation du système. Nos méthodes permettent également de résoudre les régions centrales (< 1 kpc) des galaxies hôtes et den analyser le contenu. Suite à ce projet, une étude dun plus grand échantillon de 104 quasars de bas redshift a été menée. Les résultats obtenus pour un sous échantillon de 69 quasars (observé avec le NTT/SUSI2 et complété par des données darchives), formant lessentiel de la seconde partie du travail, peuvent se résumer comme suit : La magnitude absolue du quasar ne se corrèle pas fortement avec celle de la galaxie hôte sur lensemble de léchantillon. Cependant, la corrélation est plus robuste si lon ne considère que les galaxies elliptiques. La proportion de galaxies arborant des traces dinteractions gravitationnelles (' 60%) est assez élevée, mais cela ne permet pas de déterminer univoquement si elles influencent lactivation du quasar. Les hôtes possèdent en moyenne une plus grande quantité de gaz ionisé par rapport aux galaxies inactives. Cette tendance est encore plus forte pour les elliptiques, qui pourtant ne contiennent quune faible quantité de gaz lorsquelle sont inactives. Les galaxies hôtes les plus asymétriques, associées à des collisions galactiques majeures, contiennent également plus de gaz ionisé que les moins asymétriques. Quelques elliptiques de léchantillon possèdent un noyau actif décentré par rapport au centre de leur galaxie. Ce décentrage suggère une collision galactique importante, voire même une éjection du trou noir avec son disque daccrétion à partir de la fusion dun système binaire de trous noirs. Quelques cas particuliers, méritant dêtre observés à plus haute résolution spatiale et en spectro-3D, sont décrits pour la première fois. La thèse se compose des deux articles liés aux études résumées ci-dessus. Le premier, publié dans lAstrophysical Journal en juin 2008 (Letawe et al. [72]), traite des images HST et des spectres VLT, et le second, soumis au Monthly Notices of the Royal Astronomical Society en septembre 2009, contient lanalyse de léchantillon SUSI2. Ces articles sont complétés par des contextualisations et analyses supplémentaires non publiées. This work consists in the study of two samples of nearby luminous quasars. First of all,we compare quasar images obtained from the Hubble Space Telescope and slit spectra from the VLT/FORS1 in order to study the properties of six quasar host galaxies. An appropriate data processing, based on the MCS deconvolution method, allows to separate the central source from the host and to describe their content in detail. We are able to characterize the quasars influence on its surrounding. Indeed, our analysis proves the presence of gas ionized by the quasar in remote regions apparently devoid of stars, but also the presence of quasar emission lines reflected by free electrons or dust. The dynamics of the gas surrounding the quasar is revealed via rotation curves and information about the central regions (< 1 kpc) is accessible thanks to our powerful quasar-host separation methods. As a second part, a study of a larger sample of 104 nearby quasars is made. Results for a subsample of 69 quasars (observed with NTT/SUSI2 and completed with archive data) form the second part of this work. They can be summarized as follows : The quasars absolute magnitude does not correlate strongly with the host magnitude. However, this correlation becomes more robust if we consider only elliptical hosts. The proportion of galaxies showing signs of gravitational interactions is quite large (' 60%), but this does not allow to assess unequivocally their influence in the triggering of the quasar activity. There is a tendency for quasar hosts to contain more ionized gas than in inactive galaxies. This trend is even stronger for ellipticals, which, when inactive, do not usually contain much gas. The most asymmetric hosts, linked to strong merging processes, also tend to have more ionized gas than less asymmetric ones. A few ellipticals have their active nucleus shifted compared to the galactic center. Such ff-nuclear activity is suggestive of important galactic collisions, and may be due to a gravitational black hole recoil in the fusion of binary black holes system. A few peculiar cases, deserving higher resolution imaging or 3D-spectroscopy, are described here for the first time. The thesis is composed of two articles linked to the two studies summarized above. The first one, published in the Astrophysical Journal in June 2008 (Letawe et al. [72]), deals with HST and VLT data. The second one, submitted to the Monthly Notices of the Royal Astronomical Society in September 2009, contains the analysis of the SUSI2 sample. These articles are completed by introductions and unplublished supplementary analyses and results.

With the use of touch-screen enabled interfaces, came a new era for in-car interactions. Sadly, no technology comes without drawbacks, in this case the demand of visual attention, which is desperately needed to operate the vehicle in a safe manner. The main motivation for this project is finding a way to bring the sense of touch back to interfaces while retaining the flexibility that touch-screens have introduced. The collaborating partner for this project was Icon Incar, who also supported it in many ways. The research phase of this project has been carried out at the company HQ in Berlin. This included feedback sessions at the company, reading research papers on haptics and automotive interfaces, talking to experts in the field of haptics and the facilitation of a workshop. The research helped to confirm the initial problem statement and helped to form ideas in the ideation stage, of which there were many. Those ideas were a mixture of technologies and sensing abilities that went far beyond the initial problem statement in order keep a brother scope. There were many feedback session, with different people, which were necessary to weed out the bad ideas and keep the viable ones for testing. While building and testing the first prototypes, there was simultaneously a quest going on to find a solution for fully actuated and shape shifting displays, something that has not been done before. While coming up with dozens of possible technical solutions, the fact was overlooked that none of them would provide a good experience (except some far fetched futuristic granular systems). As it turns out, actuating the display itself would not cause any problems, but manipulating the actuation would, because it would not give the best experience. Manipulating actuated button would work and feel just fine, but sliders and knobs - whenever the finger has to move over a surface - would feel unnatural. After more analysis, I found that there is not one technology yet, that could stimulate all the different properties a human being can feel with the sense of touch. Therefor, there have to be many technologies working together to provide the best possible experience. More than a dozen haptic prototypes have been built and tested to help the users perform various tasks blindly. Those ranged from controlling the climate, scrolling throughout lists, identifying functions and getting feedback for selected options. Many of the ideas did not work out as expected and were discontinued after the haptic testing, which was a vital part of the process. The working ideas were then combined into a larger concept. To simplify the interface even more, a general list of features was thoroughly studied so that functions could be simplified, combined or discarded. Drivers and car dealers have been interviewed to understand what the most commonly used functions are. The analysis of existing interfaces has shown that there is currently only one function and type of information provided at any time. This means that the driver can not see directions while changing the music, for example. The concept layout will, therefore, provide information about all the basic functions (climate control, navigation, music and phone) where one function shows all information and others only the basics. To avoid visual clutter and ensure quick recognition, graphic elements have been distilled to their essential forms while still retaining a sense of visual pleasure. To identify, differentiate between and set climate control, the knob for heating would change its temperature, the ventilation knob blow air at the set speed and the air flow direction knob would tilt in the set direction. While the volume knob would react to the beat of the music. With the help of microfluidics, active buttons would pop out of the screen and can be identified by their shapes. When activating those shape shifting buttons, the driver would feel feedback, similar to the one of real buttons, provided by an actuator at the back of the display. The combination of all listed solutions would provide simpler interactions and help the drivers to keep their focus on the road. This would in turn make driving a better and safer experience.