Pathologisches Glücksspiel (PG) ist eine psychiatrische Erkrankung, die gerade erst im DSM-5 der gleichen Kategorie wie substanzgebundene Suchterkrankungen zugeordnet wurde. Bildgebungsstudien zu Substanzabhängigkeit beobachteten funktionelle und strukturelle Veränderungen im präfrontalen Kortex (PFC) und mesolimbischen Belohnungssystem (d.h. Striatum). Für PG wurden ähnliche Veränderungen berichtet; jedoch gibt es kaum Studien, die sich mit verschiedenen Aspekten funktioneller und struktureller Korrelate in diesen Regionen beschäftigen. Diese Arbeit untersuchte PG Patienten, alkoholabhängige (AD) Patienten und Kontrollpersonen (HC) mit Magnetresonanztomografie. In Analyse I wurden funktionelle Gehirndaten während der Belohnungsaufgabe zwischen den drei Gruppen verglichen. In Analyse II wurde das Volumen grauer Substanz mit voxelbasierter Morphometrie und in Analyse III die intrinsische Gehirnaktivität mit einer seedbasierten funktionellen Konnektivitätsanalyse von PG Patienten und HC ausgewertet. Die Analysen ergaben veränderte Aktivierungen in frontostriatalen Arealen während der Verarbeitung von Verlustvermeidung für PG Patienten im Vergleich zu HC. PG Patienten unterschieden sich dabei in ihrer Aktivierung von AD Patienten während der Antizipation von Geldverlust. Weiterhin zeigten PG Patienten erhöhte Volumina grauer Substanz und eine erhöhte funktionelle Konnektivität in frontostriatalen Arealen im Vergleich zu HC. Die Ergebnisse liefern weitere Hinweise für eine veränderte Belohnungsverarbeitung in PG und betonen die Bedeutung der Verlustvermeidungsverarbeitung. Die Volumenveränderungen im und die erhöhte Konnektivität zwischen dem PFC and Belohnungssystem deuten auf eine veränderte Interaktion zwischen diesen Regionen hin. Da solche Veränderungen in kortikostriatalen Systemen Ähnlichkeiten zu denen in Substanzabhängigkeiten aufweisen, unterstützen die Ergebnisse die neue Klassifikation des PG im DSM-5. / Pathological gambling (PG) is a psychiatric disorder newly classified under the same category as substance use disorders in the DSM-5. Neuroimaging studies on substance-related addictions reported functional and structural changes in the prefrontal cortex (PFC) and the mesolimbic reward system (i.e., striatum). For PG, findings are not that extensive, but also demonstrate altered reward processing and prefrontal function. However, there is a lack of studies focusing on different aspects of functional and structural correlates within these areas in PG. This thesis investigated PG patients, alcohol dependent (AD) patients and healthy controls with magnetic resonance imaging (MRI). In analysis I, functional brain data of a reward paradigm was compared between the three groups. In analysis II, local gray matter volume of PG patients and controls was processed via voxel-based morphometry. Resting-state data of PG patients and controls was analyzed via seed-based functional connectivity in analysis III. Results revealed altered brain responses in fronto-striatal areas during loss avoidance processing in PG patients as compared to controls. Importantly, PG patients differed in their brain responses from AD patients during the prospect of monetary loss. Moreover, PG patients showed an increase in local gray matter volume and functional connectivity in frontal-striatal areas as compared to controls. Our results add further evidence for an altered reward processing in PG and underline the importance of loss avoidance processing. Moreover, our findings of volumetric alterations within and increased connectivity between PFC and reward system, suggest an altered interaction between these brain regions. Since such alterations in cortico-striatal circuits resemble those reported for substance-related addictions, our findings support the new classification of PG in the DSM-5.

The glass-forming composition ranges in Al-La-Ni and Mg-TM (Cu, Zn)-Y alloys were predicted using Miedema’s model. Glass-forming abilities of Al-La-Ni alloys and Mg-Cu-RE alloys were studied in terms of reduced glass transition temperature (Trg), supercooled liquid region (∆Tx) and γ parameters. The glass-forming ability parameters of Mg-Cu-RE (RE: rare-earth) alloys were correlated with Mendeleev number. The Miedema model has been used to determine glass-forming composition range in binary Al-La, Al-Ni and La-Ni alloy systems and the ternary Al-La-Ni system by neglecting the ternary interactions. The glass-forming composition range for Al-La, Al-Ni and La-Ni alloy systems extends from 5 to 90 at% La, 30 to 80 at% Ni and 5 to 95 at% Ni, respectively. In these systems the predicted glass-forming composition range is wider than the experimentally observed range. Miedema model, restricting the difference of enthalpy of formation between the amorphous and solid solution phases to within –10000 J/mole to –55000 J/mole gives rise to better prediction of glass-forming composition range compared to the original models. The concept of mixing enthalpy and mismatch entropy has been used in order to quantify Inoue’s criteria of glass formation. The mixing enthalpy and normalised mismatch entropy of the ternary Al-La-Ni alloys, calculated by the extended regular solution model, vary between –12 to –40 kJ/mol and 0.16 to 0.65, respectively. The enthalpy contour plot has been constructed to distinguish the glass-forming compositions on the basis of the increasing negative enthalpy of the composition. Six Al rich Al-La-Ni alloys with nominal compositions Al89La6Ni5, Al85La10Ni5, Al85La5Ni10, Al82La8Ni10, Al80La10Ni10 and Al60La20Ni20 three La rich Al-La-Ni alloys with nominal compositions Al34La33Ni33, Al40La40Ni20 and Al25La50Ni25 have been chosen from the Al-La-Ni ternary phase diagram, to study the glass-forming ability of Al-La-Ni ternary alloy system and the correlation between La-based and Al-based glasses. All the alloys have been prepared using arc melting unit. All the alloy ribbons have been prepared using single-wheel vacuum melt-spinning unit. Two different wheel speeds of 20 m/s and 40 m/s were used for preparing ribbons of all the nine alloys. All the Al-La-Ni compositions, excluding equi-atomic composition (Al34La33Ni33) and Al60La20Ni20, give rise to amorphous phases. The supercooled liquid region and reduced glass transition temperature of this system increases with a decrease in Al content and an increase in La content. The glass-forming ability of the Al rich Al-La-Ni alloys is lower than that of the La-rich Al-La-Ni alloys. The glass-forming ability has been explained by taking into account the binary heat of mixing and the atomic radius mismatch of the constituent elements. Preferential crystallisation takes place during the heat treatment of glassy ribbons. The crystalline products are partially influenced by composition and binary heat of mixing between elements. Mg65Cu25Y10 alloy is a classical glass former of a family of Mg-based alloys. The partial or complete substitution of Y with other rare earth elements has been introduced to correlate the Mendeleev Number with the glass-forming ability parameters: reduced glass transition temperatures (Trg = Tg/Tl), supercooled liquid regions (∆Tx = Tx – Tg) and γ-criterion (TX/(Tg + Tm)). Mg-Cu-RE alloys with nominal compositions Mg65Cu25Y10, Mg65Cu25Y5Gd5, Mg65Cu25Y5Nd5, Mg65Cu25Gd10 and Mg65Cu25Nd10 were chosen for this work. The high reduced glass transition temperature, wider supercooled liquid region and higher γ value of Mg-Cu-Gd-Y amorphous alloy compared to Mg-Cu-Y and Mg-Cu-Nd-Y systems indicates that Mg-Cu-Gd-Y alloys possess higher glass-forming ability. The devitrification of all Mg-Cu-RE glassy alloys used for this work give rise to Mg2Cu (oF48) phase, which is known as anti-Laves phase. The glass-forming composition range for binary and ternary Mg-Cu-Y systems was calculated using Miedema’s model. The development of accurate methods of prediction of glass-forming ability in metallic systems is an important challenge. Pettifor has pioneered the Structure Mapping approach to binary intermetallics. The Pettifor approach can be adapted to the designing of bulk metallic glasses (BMGs). This method has been used to design Al-based and Mg-based BMG’s. Pettifor introduced an integer parameter to characterize the elements, which he called the Mendeleev Number. Essentially, Pettifor’s scheme orders the elements in a sequence of increasing electronegativity. With respect to Mendeleev Number, the Mg-Cu-RE system can be regarded as a binary system, because of the closeness of Mg and Cu (Mg:73, Cu:72, Y:25, Gd:27 and Nd:30). For this system, Mendeleev Number is a more effective parameter than atomic size (Mg: 1.60 Å, Cu: 1.27 Å), as a predictor of glass-forming ability. The effect of Y and rare earth elements on glass forming ability is similar. The atomic number of Y (39) is away from that of the rare earth elements and the Mendeleev Number of Y (25) comes in between those of the rare earth elements. Mg-Zn-Y system is an interesting system for researchers because of higher strength of these alloys. This system draws the crystallographers’ attention due to its composition-dependent structure variations. The Mg-rich RS/PM Mg-Zn-Y alloys yield superior mechanical properties. Therefore, the Mg-rich Mg-Zn-Y system has been chosen to study the microstructural evolution, even though the theoretical calculations for the glass-forming composition range for the Mg-Zn-Y system shows that this system is not a good glass former. Mg-Zn-Y system with nominal compositions Mg97Zn1Y2, Mg97Zn2Y1, Mg97−xZn1Y2Zrx and Mg92Zn6.5Y1.5 were chosen to study the microstructural evolution of these alloys. A small increase in Zn amount (above 2 at.%) in Mg-rich Mg-Y system results in quasicrystalline particles embedded in the matrix, whereas the addition of Zn up to 2 at.% leads to microstructural changes in the α-Mg solid solution.

L' étude d'une technique originale de croissance cristalline, basée sur l'utilisation d'un échangeur thermique et nommée HEM (Heat Exchanger Method), a été entreprise. Un dispositif expérimental a été développé et optimisé. La modélisation des échanges thermiques a conduit a l'élaboration d'un code de calcul numérique. Ce dernier est valide par confrontation des résultats de la simulation aux données expérimentales obtenues lors de la croissance d'un matériau école, le germanium. Le champ d'application de la technique HEM a alors été étendu à l'obtention de céramiques texturées du supraconducteur à haute température critique YBa2Cu3O7-x. Après une étude de la microstructure des textures, un mécanisme de texturation est proposé. Enfin, des cristaux du compose NaMgF3 (perovskite) sont obtenus par HEM. Leur étude en température, par observation des domaines ferroélastiques et par spectroscopie Raman, révèle l'existence d' une seule transition de phase.

科学研究費補助金 研究種目:一般研究(B) 課題番号:05452196 研究代表者:後藤 俊夫 研究期間:1993-1994年度

科学研究費補助金 研究種目:基盤研究(B)(2) 課題番号:10555255 研究代表者:藤澤 敏治 研究期間:1998-2000年度

名古屋大学年代測定総合研究センターシンポジウム報告

This thesis describes two different sample preparation strategies for inductively coupled plasma atomic emission spectrometry (ICP-AES), and their ability regarding multi element quantification in complex samples. Sensitivity, repeatability, reproducibility and accuracy were investigated. The aim was to increase the over all efficiency, the speed of analysis, and/or the sensitivity of the analytical method. The intention was to measure analytes with concentrations ranging from ng/g to mg/g simultaneously. The aim was additionally to study chemical and physical processes occurring during the sample preparation, the sample transport to the plasma, and the atomization therein. In the first sample preparation strategy, a hydrophilic highly cross-linked iminodiacetate-agarose adsorbent, IDA-Novarose, was used for preconcentration of metal ions, and matrix elimination in natural water samples. The sorbent was synthesized with different binding capacities. The effect of the capacity on preconcentration, matrix elimination, and uptake capability at high flow rates was studied. For a high capacity IDA-Novarose (≥ 45 µmole/ml) quantitative uptake was seen even at high flow rates (100 ml/min) for Cu2+ with a high affinity to the adsorbent, and for Cd2+ with a moderate affinity. For lower capacities the uptake of Cd2+ was affected by the sample matrix and the flow rate. A method based on the determination of the conditional stability constant of the metal sorbent complex was suggested for the prediction of the sorbent capacity needed to obtain quantitative recovery and optimal matrix elimination. The sorbent was used in a flow system with online buffering for the analysis of a certified riverine water (SLRS-3), tap water and lake water. With few exceptions the results obtained by ICP-AES after preconcentration agreed well with the certified concentrations and results obtained by ICP-MS. The other sample preparation strategy discussed is a method for non digested biological samples from different animal organs for the multi element analysis by ICP-AES. This “mix and measure method” consists of a simple homogenization of the sample with a mixing rod in a small amount of neutral media, followed by dilution and direct measurement with ICP-AES. The total time of analysis is only a few minutes. The ability of this fast method to accurately quantify some elements of toxic, environmental, and/or physiological concern with the lowest possible sample dilution and the highest possible plasma load was evaluated. In 10 % liver slurry Cd, Co, and Sr, at concentration levels around 0.05 µg/g were quantified simultaneously with P and K around 2000 µg/g and with several other elements in between (Al, Ca, Cu, Fe, Mg, Mn, Pb, and Zn). The relative standard deviation of repeated measurements of samples was around 5 - 6 % for regardless of the concentration of the element. The method was also used for fast screening of the elemental distribution in mice organs (brain, heart, kidney, liver, lung and spleen).

Esta tesis doctoral es una colección de tres artículos. Los capítulos 1 y 2, co-autorados con Joachim Voth, investigan por qué Europa en 1700 ya era más rico que el resto del mundo y por qué Inglaterra fue el primer país en industrializarse. Encontramos que las dinámicas de la población, en lugar del crecimiento de la productividad, fueron los promotores más importantes del desarrollo económico de Europa Occidental durante la temprana edad moderna (1450-1700). Calibramos un modelo probabilístico para representar Inglaterra en 1700 y encontramos que ingresos iniciales más altos unidos a limitaciones de fertilidad aumentaron la probabilidad de industrialización. En el tercer capítulo, presento un nuevo hecho estilizado y analizo su contribución al sesgo del cambio tecnológico hacia los trabajadores más cualificados: El porcentaje de trabajadores cualificados en la producción intermedia está altamente correlacionado con la proporción de trabajo cualificado en la producción final. Esto genera un efecto multiplicador que refuerza la demanda de trabajo cualificado a lo largo de la cadena de producción. El efecto es importante, explica más de un tercio del aumento de la demanda de trabajadores cualificados en la industria manufacturera de EE.UU. / This dissertation is a collection of three essays. Chapters 1 and 2, co-authored with Joachim Voth, investigate the question why Europe in 1700 was ahead of the rest of the world and why England was the first country to industrialize. We find that population dynamics, rather than productivity growth, were the most important drivers for Western Europe to overtake China in the early modern period (1450-1700). We calibrate a probabilistic model to match England in 1700 and find that higher initial per capita incomes together with fertility limitation increased its industrialization probabilities. In the third chapter, I present a novel stylized fact and analyze its contribution to the skill bias of technical change: The share of skilled labor embedded in intermediate inputs correlates strongly with the skill share employed in final production. This delivers a multiplier that reinforces skill demand along the production chain. The effect is large, accounting for more than one third of the observed skill upgrading in U.S. manufacturing.

Ceramic metal matrix composites (CMMCs) are materials generally created by mixing of hard ceramic particles in a metal matrix. They were expected to combine the ductility and toughness of the metal with the high strength and elastic modulus of the ceramic. MMCs have potential applications in automotive, aeronautical and aerospace industries. Hence, a simple and economical method for fabricating MMCs is an area of intense research. In MMCs, damage evolution starts preferentially at particle matrix interface or at particle clusters in the matrix. This is due to the different physical and mechanical properties of the particle and matrix. Higher local particle volume content leads to higher stress triaxiality making it a preferential site for damage nucleation. Problems with lowering of ductility, fatigue, fracture and impact resistance, agglomeration of ceramic phase and issues related to the predictability of properties of MMCs have been the major issues that have limited their use. In order to overcome some of these shortcomings, the use of nano particles has been attracting increasing attention. The reason is their capability in improving the mechanical and physical properties of traditional MMCs. The dispersion of a nanoscale ceramic phase is needed in order to overcome the problems related to fatigue, fracture toughness, and creep behaviour at high temperatures. However, manufacturing costs, preparation of nano composites and environmental concerns have to be addressed. Agglomeration of nano particles, when produced by the melt stir casting route, the primary route to produce MMCs, is a serious issue that limits the use of nano-particles to produce MMCs with good properties. To avoid agglomeration of the ceramic phase MMCs/nano MMCs have been produced through the powder metallurgy route. Agglomeration is avoided as this is a solid state process. Secondary processing, such as extrusion and rolling are often needed to fully consolidate materials produced in this manner. A high extrusion ratio is often required to get MMCs without porosity. A new method of making nano-ceramic MMC using a polymer derived ceramics (PDC) has been reported. A polymer derived ceramic is a material that converts itself into a ceramic when heated above a particular temperature. In the PDC method a polymer precursor is dispersed in the metal and then converted in-situ to a ceramic phase. A feature of this process is that all the constituents of the ceramic phase are built into the organic molecules of the precursor (e.g., polysilazanes contain silicon, carbon, and nitrogen); therefore, a reaction between the polymer and the host metal or air is not required to produce the ceramic phase. The polymer can be introduced through casting or powder metallurgy route. In the casting route, the polymer powder is directly added to molten metal and pyrolyzed in-situ to create castings of metal-matrix composites. These composites have shown better properties at elevated temperatures but the problem of agglomeration of particles due to Van der Waal's forces and porosity still remains. In the powder method, the organic precursor was milled with copper powder and then plasma sprayed to produce a metal matrix composite. It is reported that these composites retains its mechanical strength close to the melting point of the copper. However, getting a nano sized distribution is difficult through this route as the plasma spray route is a melting and solidification method. Solid state processing by powder metallurgy is possibly a better method to produce well dispersed nano-MMCs. However, powder metallurgy routes are much more expensive and only parts of limited sizes can be produced by this method. Another solid state process Friction Stir Processing (FSP) has successfully evolved as an alternative technique to fabricating metal matrix composites. FSP is based on the principles of Friction Stir Welding (FSW). In FSW, a rotating tool with a pin and a shoulder is inserted into the material to be joined, and traversed along the line of the joint. The friction between the tool and the work piece result in localized heating that softens and plasticizes the material. During production of MMCs using FSP method, the material undergoes intense plastic deformation resulting in mixing of ceramic particles and the metal. FSP also results in significant grain refinement of the metal and has also been used to homogenize the microstructure. FSP technology has also been used to fabricate surface/bulk composites of Al-SiC, friction stir surfacing of cast aluminum silicon alloy with boron carbide and molybdenum disulphide powders and to produce ultra-fine grained Cu-SiC composites. A major problem in the FSP of MMCs is severe tool wear that results from abrasion with hard ceramic particles. The progressive wear of the tool has been reported to increase the likelihood of void or defect development. This change in geometry has been reported in the friction stir welding of several MMCs. The problems concerning the tool life has become a serious issue in the application of FSP for producing MMCs. In the present work the advantages of the PDC method and FSP have been combined to produce polymer derived nano ceramic MMCs. This method mainly consists of three steps. In the first step, a polymer, which pyrolysis to form a PDC at temperatures lower than the melting point of the metal, is dispersed in the metal by FSP. This step is different from the melt route where the PDC forms at temperatures above the melting point of the metal. In the second step, external pyrolysis of the polymer dispersed material is carried out. Since this is a solid state process at stresses much higher than the shear or fracture of the polymer is expected to get evenly and finely distribution in the metal. This is done by heating the polymer dispersed material to a temperature above the pyrolysation temperature of the ceramic but lower than the melting point of the metal matrix. It should be mentioned that some pyrolysis of the polymer is possible during the FSP process itself. In the third step FSP is carried out on the pyrolised material for removing porosity that would form due to gas evolution during pyrolysis and to get a more uniform dispersion of polymer derived ceramic particles in the matrix. This method will produce nano-scale metal matrix composites with a relatively high volume fraction of the ceramic phase. This method can be extended to big sheets or a particular region in a sheet with no or low wear of tools. The material selected for the present study were pure Copper (99.9%) and Nickel Aluminum Bronze (NAB) copper alloy. The polymer precursor was poly (urea methyl vinyl) silazane, which is available commercially as CERASET. The polymer consists of silicon, carbon, nitrogen, oxygen and hydrogen atoms. The liquid precursor was thermally cross-linked into a rigid polymer, which was milled into a powder. This powder, having angular shaped particles of an average size of 10 µm, was used as the reinforcement. The polysilazanes convert into a highly refractory and amorphous ceramic upon pyrolysis and is known as polymer-derived silicon carbonitride which consists principally of silicon, carbon and nitrogen. The in-situ process is feasible because copper melts above the temperature at which the organic phase begins to pyrolise. The polysilazanes pyrolise in the temperature range of 973 to 1273 K, which lie below the melting temperature of copper, 1356K.The precursor has a density of approximately 1 gcm-3 in the organic phase and approximately 2 gcm-3 in the ceramic state. In the present work, we seek to introduce approximately 20 vol% of the ceramic phase into copper. The microstructure and mechanical properties of the developed copper-based in-situ polymer derived nano MMCs have been characterized in detail to understand the distribution of particles. The microstructure of the as received, processed as well as the FSP composite material was characterized using Optical Microscope (OM), Scanning Electron Microscope (SEM), Electron Probe Micro Analyzer (EPMA) and Transmission Electron Microscope (TEM). OM and SEM microstructural observations show that PDC particles are distributed uniformly with a bimodal (submicron+micron) distribution. In addition, TEM micrographs reveal the formation of very fine PDC particles of diameter 10-30 nm. X-ray diffraction and Thermo-gravimetric analysis confirms the presence of ceramic phase (Si3N4/SiC) in the matrix. Significant improvement in mechanical properties of the FSP PD-MMCs has been observed. This in-situ formed Cu/PDC composites show five times increase in micro-hardness (260Hv - 2.5GPa) compared to processed copper base metal and in-situ NAB/PDC composite shows two times increase in micro-hardness (325Hv- 3.2GPa) compared to NAB matrix. The Cu-PDC composites exhibited better tensile strength at room temperature. In-situ formed Cu-PDC composite’s yield strength increased from 110MPa to 235MPa as compared to processed base metal, where as ultimate tensile strength increases from 246MPa to 312MPa compared to processed base metal at room temperature. This strengthening could be attributed to the presence of in-situ formed hard phases and the concomitant changes in the microstructure of the matrix material such as reduction in grain size and contribution from Orowan strengthening. In the present work, we have observed tool wear by observing tool after each FSP pass and apart from producing a significantly harder material with higher elastic modulus, possibly for the first time, the issue of tool wear has been overcome. This is due to the fact that the composite is made by the polymer route and that the ceramic fractures easily till it reaches the nano-size. Wear studies of this composite was carried out in a pin-on-disc machine by sliding a pin made from the composite against an alumina disc. The wear rate of the FSP PD-MMC composites increased from 1.63×10-5 to 5.72×10-6 mm3/Nm. Improved wear resistance could be attributed to the presence of the in-situ formed hard nano-phase.

This thesis describes the synthesis, characterisation and application of artificial metalloenzymes as catalysts. The focus was on two mutants of SCP-2L (SCP-2L A100C and SCP-2L V83C) both of which possess a hydrophobic tunnel in which apolar substrates can accumulate. The crystal structure of SCP-2L A100C was determined and discussed with a special emphasis on its hydrophobic tunnel. The SCP-2L mutants were covalently modified at their unique cysteine with two different N-ligands (phenanthroline or dipicolylamine based) or three different phosphine ligands (all based on triphenylphosphine) in order to increase their binding capabilities towards metals. The metal binding capabilities of these artificial proteins towards different transition metals was determined. Phenanthroline modified SCP-2L was found to be a promising scaffold for Pd(II)-, Cu(II)-, Ni(II)- and Co(II)-enzymes while dipicolylamine-modified SCP-2L was found to be a promising scaffold for Pd(II)-enzymes. The rhodium binding capacity of two additional phosphine modified protein scaffolds was also investigated. Promising scaffolds for Rh(I)- and Ir(I)-enzymes were identified. Rh-enzymes of the phosphine modified proteins were tested in the aqueous-organic biphasic hydroformylation of linear long chain 1-alkenes and compared to the Rh/TPPTS reference system. Some Rh-enzymes were found to be several orders of magnitude more active than the model system while yielding comparable selectivities. The reason for this remarkable reactivity increase could not be fully elucidated but several potential modes of action could be excluded. Cu-, Co-, and Ni-enzymes of N-ligand modified SCP-2L A100C were tested in the asymmetric Diels-Alder reaction between cyclopentadiene and trans-azachalcone. A promising 29% ee for the exo-product was found for the phenanthroline modified protein in the presence of nickel. Further improvement of these catalyst systems by chemical means (e.g. optimisation of ligand structure) and bio-molecular tools (e.g. optimisation of protein environment) can lead to even more active and (enantio)selective catalysts in the future.