The Homeless Etiquette : Social Interaction and Behavior Among the Homeless in Taito Ward, Tokyo

The thesis focuses on the social interaction and behavior of the homeless living in Tokyo's Taito Ward. The study is based on the author's own ethnographic field research carried out in the autumn 2003. The chosen methodologies were based on the methodology called "participant observation", and they were used depending on the context. The ethnographic field research was carried out from the mid-August to the beginning of the October in 2003. The most important targets of the research were three separate loosely knit groups placed in certain parts of Taito Ward. One of these groups was based in proximity to the Ueno train station, one group gathered every morning around a homeless support organization called San'yûkai, and one was based in Tamahime Park located in the old San'ya area of Tokyo. The analysis is based on the aspects of Takie Sugiyama Lebra's theory of "social relativism". Lebra's theory consists of the following, arguably universal aspects: belongingness, empathy, dependence, place in the society, and reciprocity. In addition, all the interaction and behavior is tied to the context and the situation. According to Lebra, ritual and intimate situations produce similar action, which is socially relative. Of these, the norms of the ritual behavior are more regulated, while the intimate bahavior is less spontaneous. On the contrary, an anomic situation produces anomic behavior, which is not socially relative. Lebra's theory is critically reviewed by the author of the thesis, and the author has attempted to modify the theory to make it more adaptable to the present-day society and to the analysis. Erving Goffman's views of the social interaction and Anthony Giddens' theories about the social structures have been used as complementary thoretical basis. The aim of the thesis is to clarify, how and why the interaction and the behavior of some homeless individuals in some situations follow the aspects of Lebra's "social relativism", and on the other hand, why in some situations they do not. In the latter cases the answers can be sought from regional and individual differences, or from the inaptness of the theory to analyze the presented situation. Here, a significant factor is the major finding of the field study: the so called "homeless etiquette", which is an abstract set of norms and values that influences the social interaction and behavior of the homeless, and with which many homeless individuals presented in the study complied. The fundamental goal of the thesis is to reach profound understanding about the daily life of the homeless, whose lives were studied. The author argues that this kind of profound understanding is necessary in looking for sustainable solutions in the areas of social and housing policy to improve the position of the homeless and the qualitative functioning of the society.

Capillary electrochromatography: a versatile instrumental technique for nanodomain interaction studies

This doctoral thesis describes the development of a miniaturized capillary electrochromatography (CEC) technique suitable for the study of interactions between various nanodomains of biological importance. The particular focus of the study was low-density lipoprotein (LDL) particles and their interaction with components of the extracellular matrix (ECM). LDL transports cholesterol to the tissues through the blood circulation, but when the LDL level becomes too high the particles begin to permeate and accumulate in the arteries. Through binding sites on apolipoprotein B-100 (apoB-100), LDL interacts with components of the ECM, such as proteoglycans (PGs) and collagen, in what is considered the key mechanism in the retention of lipoproteins and onset of atherosclerosis. Hydrolytic enzymes and oxidizing agents in the ECM may later successively degrade the LDL surface. Metabolic diseases such as diabetes may provoke damage of the ECM structure through the non-enzymatic reaction of glucose with collagen. In this work, fused silica capillaries of 50 micrometer i.d. were successfully coated with LDL and collagen, and steroids and apoB-100 peptide fragments were introduced as model compounds for interaction studies. The LDL coating was modified with copper sulphate or hydrolytic enzymes, and the interactions of steroids with the native and oxidized lipoproteins were studied. Lipids were also removed from the LDL particle coating leaving behind an apoB-100 surface for further studies. The development of collagen and collagen decorin coatings was helpful in the elucidation of the interactions of apoB-100 peptide fragments with the primary ECM component, collagen. Furthermore, the collagen I coating provided a good platform for glycation studies and for clarification of LDL interactions with native and modified collagen. All methods developed are inexpensive, requiring just small amounts of biomaterial. Moreover, the experimental conditions in CEC are easily modified, and the analyses can be carried out in a reasonable time frame. Other techniques were employed to support and complement the CEC studies. Scanning electron microscopy and atomic force microscopy provided crucial visual information about the native and modified coatings. Asymmetrical flow field-flow fractionation enabled size measurements of the modified lipoproteins. Finally, the CEC results were exploited to develop new sensor chips for a continuous flow quartz crystal microbalance technique, which provided complementary information about LDL ECM interactions. This thesis demonstrates the potential of CEC as a valuable and flexible technique for surface interaction studies. Further, CEC can serve as a novel microreactor for the in situ modification of LDL and collagen coatings. The coatings developed in this study provide useful platforms for a diversity of future investigations on biological nanodomains.

Intermolecular Interactions of Noble-Gas-Containing Species

The importance of intermolecular interactions to chemistry, physics, and biology is difficult to overestimate. Without intermolecular forces, condensed phase matter could not form. The simplest way to categorize different types of intermolecular interactions is to describe them using van der Waals and hydrogen bonded (H-bonded) interactions. In the H-bond, the intermolecular interaction appears between a positively charged hydrogen atom and electronegative fragments and it originates from strong electrostatic interactions. H-bonding is important when considering the properties of condensed phase water and in many biological systems including the structure of DNA and proteins. Vibrational spectroscopy is a useful tool for studying complexes and the solvation of molecules. Vibrational frequency shift has been used to characterize complex formation. In an H-bonded system A∙∙∙H-X (A and X are acceptor and donor species, respectively), the vibrational frequency of the H-X stretching vibration usually decreases from its value in free H-X (red-shift). This frequency shift has been used as evidence for H-bond formation and the magnitude of the shift has been used as an indicator of the H-bonding strength. In contrast to this normal behavior are the blue-shifting H-bonds, in which the H-X vibrational frequency increases upon complex formation. In the last decade, there has been active discussion regarding these blue-shifting H-bonds. Noble-gases have been considered inert due to their limited reactivity with other elements. In the early 1930 s, Pauling predicted the stable noble-gas compounds XeF6 and KrF6. It was not until three decades later Neil Bartlett synthesized the first noble-gas compound, XePtF6, in 1962. A renaissance of noble-gas chemistry began in 1995 with the discovery of noble-gas hydride molecules at the University of Helsinki. The first hydrides were HXeCl, HXeBr, HXeI, HKrCl, and HXeH. These molecules have the general formula of HNgY, where H is a hydrogen atom, Ng is a noble-gas atom (Ar, Kr, or Xe), and Y is an electronegative fragment. At present, this class of molecules comprises 23 members including both inorganic and organic compounds. The first and only argon-containing neutral chemical compound HArF was synthesized in 2000 and its properties have since been investigated in a number of studies. A helium-containing chemical compound, HHeF, was predicted computationally, but its lifetime has been predicted to be severely limited by hydrogen tunneling. Helium and neon are the only elements in the periodic table that do not form neutral, ground state molecules. A noble-gas matrix is a useful medium in which to study unstable and reactive species including ions. A solvated proton forms a centrosymmetric NgHNg+ (Ng = Ar, Kr, and Xe) structure in a noble-gas matrix and this is probably the simplest example of a solvated proton. Interestingly, the hypothetical NeHNe+ cation is isoelectronic with the water-solvated proton H5O2+ (Zundel-ion). In addition to the NgHNg+ cations, the isoelectronic YHY- (Y = halogen atom or pseudohalogen fragment) anions have been studied with the matrix-isolation technique. These species have been known to exist in alkali metal salts (YHY)-M+ (M = alkali metal e.g. K or Na) for more than 80 years. Hydrated HF forms the FHF- structure in aqueous solutions, and these ions participate in several important chemical processes. In this thesis, studies of the intermolecular interactions of HNgY molecules and centrosymmetric ions with various species are presented. The HNgY complexes show unusual spectral features, e.g. large blue-shifts of the H-Ng stretching vibration upon complexation. It is suggested that the blue-shift is a normal effect for these molecules, and that originates from the enhanced (HNg)+Y- ion-pair character upon complexation. It is also found that the HNgY molecules are energetically stabilized in the complexed form, and this effect is computationally demonstrated for the HHeF molecule. The NgHNg+ and YHY- ions also show blue-shifts in their asymmetric stretching vibration upon complexation with nitrogen. Additionally, the matrix site structure and hindered rotation (libration) of the HNgY molecules were studied. The librational motion is a much-discussed solid state phenomenon, and the HNgY molecules embedded in noble-gas matrices are good model systems to study this effect. The formation mechanisms of the HNgY molecules and the decay mechanism of NgHNg+ cations are discussed. A new electron tunneling model for the decay of NgHNg+ absorptions in noble-gas matrices is proposed. Studies of the NgHNg+∙∙∙N2 complexes support this electron tunneling mechanism.

Radiation effects in supported nanoparticles

Nanotechnology applications are entering the market in increasing numbers, nanoparticles being among the main classes of materials used. Particles can be used, e.g., for catalysing chemical reactions, such as is done in car exhaust catalysts today. They can also modify the optical and electronic properties of materials or be used as building blocks for thin film coatings on a variety of surfaces. To develop materials for specific applications, an intricate control of the particle properties, structure, size and shape is required. All these depend on a multitude of factors from methods of synthesis and deposition to post-processing. This thesis addresses the control of nanoparticle structure by low-energy cluster beam deposition and post-synthesis ion irradiation. Cluster deposition in high vacuum offers a method for obtaining precisely controlled cluster-assembled materials with minimal contamination. Due to the clusters small size, however, the cluster-surface interaction may drastically change the cluster properties on deposition. In this thesis, the deposition process of metal and alloy clusters on metallic surfaces is modelled using molecular dynamics simulations, and the mechanisms influencing cluster structure are identified. Two mechanisms, mechanical melting upon deposition and thermally activated dislocation motion, are shown to determine whether a deposited cluster will align epitaxially with its support. The semiconductor industry has used ion irradiation as a tool to modify material properties for decades. Irradiation can be used for doping, patterning surfaces, and inducing chemical ordering in alloys, just to give a few examples. The irradiation response of nanoparticles has, however, remained an almost uncharted territory. Although irradiation effects in nanoparticles embedded inside solid matrices have been studied, almost no work has been done on supported particles. In this thesis, the response of supported nanoparticles is studied systematically for heavy and light ion irradiation. The processes leading to damage production are identified and models are developed for both types of irradiation. In recent experiments, helium irradiation has been shown to induce a phase transformation from multiply twinned to single-crystalline nanoparticles in bimetallic alloys, but the nature of the transition has remained unknown. The alloys for which the effect has been observed are CuAu and FePt. It is shown in this thesis that transient amorphization leads to the observed transition and that while CuAu and FePt do not amorphize upon irradiation in bulk or as thin films, they readily do so as nanoparticles. This is the first time such an effect is demonstrated with supported particles, not embedded in a matrix where mixing is always an issue. An understanding of the above physical processes is essential, if nanoparticles are to be used in applications in an optimal way. This thesis clarifies the mechanisms which control particle morphology, and paves way for the synthesis of nanostructured materials tailored for specific applications.

Tuning the interfacial properties of supported metal nanoclusters

Nanoclusters are objects made up of several to thousands of atoms and form a transitional state of matter between single atoms and bulk materials. Due to their large surface-to-volume ratio, nanoclusters exhibit exciting and yet poorly studied size dependent properties. When deposited directly on bare metal surfaces, the interaction of the cluster with the substrate leads to alteration of the cluster properties, making it less or even non-functional. Surfaces modified with self-assembled monolayers (SAMs) were shown to form an interesting alternative platform, because of the possibility to control wettability by decreasing the surface reactivity and to add functionalities to pre-formed nanoclusters. In this thesis, the underlying size effects and the influence of the nanocluster environment are investigated. The emphasis is on the structural and magnetic properties of nanoclusters and their interaction with thiol SAMs. We report, for the first time, a ferromagnetic-like spin-glass behaviour of uncapped nanosized Au islands tens of nanometres in size. The flattening kinetics of the nanocluster deposition on thiol SAMs are shown to be mediated mainly by the thiol terminal group, as well as the deposition energy and the particle size distribution. On the other hand, a new mechanism for the penetration of the deposited nanoclusters through the monolayers is presented, which is fundamentally different from those reported for atom deposition on alkanethiols. The impinging cluster is shown to compress the thiol layer against the Au surface and subsequently intercalate at the thiol-Au interface. The compressed thiols try then to straighten and push the cluster away from the surface. Depending on the cluster size, this restoring force may or may not enable a covalent cluster-surface bond formation, giving rise to various cluster-surface binding patterns. Compression and straightening of the thiol molecules pinpoint the elastic nature of the SAMs, which has been investigated in this thesis using nanoindentation. The nanoindenation method has been applied to SAMs of varied tail groups, giving insight into the mechanical properties of thiol modified metal surfaces.