Engineering of biofunctional scaffolds to precisely regulate cell behavior and tissue growth is of significance in regenerative medicine. Protein-based biomaterials are attractive candidates for functionalization of scaffold surfaces since the ability to precisely control protein sequence and structure allows for fine-tuning of cell-substrate interactions that regulate cell behavior. In this thesis, a series of de novo proteins for bio-functionalization of interfaces was designed, synthesized, and studied. These proteins are based on a diblock motif consisting of a surface-active, amphiphilic block β-sheet domain linked to a disordered, water-soluble block with a terminal functional domain. Several types of functional domains were investigated, including sequences that act as ligands for cell surface receptors and sequences that act as templates for the growth of inorganic particles. Under moderate temperature and pH conditions, the amphiphilic β-sheet block was shown to have a strong affinity to a variety of scaffold materials and to form stable protein coatings on hydrophobic materials by self-assembly. Moreover, the surface adsorption of the proteins was shown to have minimal impact on the presentation of the functional end domains in the soluble block. For the case of diblocks with the RGDS integrin binding sequence, the capability for mediating cell attachment and spreading was demonstrated via control over ligand density on hydrophobic polymer surfaces. The case of diblock proteins with templating domains for inorganic materials was investigated for two systems. First, hydroxyapatite-binding domains were ligated to the end terminus of the water-soluble block to develop proteins for possible bone regeneration applications. It was demonstrated that the hydroxyapatite-binding domain had strong affinity to hydroxyapatite nanoparticles and was able to induce calcium phosphate mineralization on the surfaces coated with diblock proteins from dilute solutions with Ca2+.and PO43-. Next, a silver-binding domain was ligated to the end terminus to create a diblock protein for potential antimicrobial surface applications. The silver-binding domain was shown to accumulate and reduce silver ions, resulting in the formation of silver nanoparticles on the surfaces functionalized by the protein.

Traditional computational protein design (CPD) calculations model sequence perturbations and evaluate their stabilities using a single fixed protein backbone template in an approach referred to as single‐state design (SSD). However, certain design objectives require the explicit consideration of multiple conformational states. Cases where a multistate framework may be advantageous over the single‐state approach include the computer aided discovery of new enzyme substrates, the prediction of protein stabilities, and the design of protein dynamics. These design objectives can be tackled using multistate design (MSD). However, it is often the case that a design objective requires the consideration of a protein state having no available structure information. For such circumstances the multistate framework cannot be applied. In this thesis I present the development of two template and ensemble preparation methodologies and their application to three projects. The purpose of which is to demonstrate the necessary ensemble modeling strategies to overcome limitations in available structure information. Particular emphasis is placed on the ability to recapitulate experimental data to guide modelling of the design space. Specifically, the use of MSD allowed for the accurate prediction of a methyltransferase recognition motif and new substrates, the prediction of mutant sequence stabilities with quantitative accuracy, and the design of dynamics into the rigid Gβ1 scaffold producing a set of dynamic variants whose tryptophan residue exchanges between two conformations on the millisecond timescale. Implementation of both the ensemble, coordinate perturbation followed by energy minimization (PertMin), and template, rotamer optimization followed by energy minimization (ROM), generation protocols developed here allow for exploration and manipulation of the structure space enabling the success of these applications.

A transmission line format is presented which takes the form of a Multilayer Ridged Substrate Integrated Waveguide, for which signal energy is transmitted within standard PCB substrates, within a wave-guiding structure formed from conducting tracks in the horizontal plane and arrays of through-plated vias in the vertical plane. The Substrate Integrated Waveguide (SIW) is a recent development into which research is so far concentrated on single-layer rectangular variants which, like traditional rectangular waveguide, are amenable to analytic computation of the cutoff eigenvalues. Recent publications have offered empirically-derived relationships with which a Substrate Integrated Waveguide can be analysed by equivalence of the horizontal dimensions with a conventional waveguide, allowing such structures to be designed with minimal effort. We propose a ridged form of this structure, in which multiple PCB layers are stacked to obtain the desired height and the published equivalent width is used to obtain the horizontal dimensions. The proposed structure combines the increased bandwidth of ridged waveguide with SIW’s greatly reduced cost of manufacture and integration, relative to conventional waveguide, and improved power handling capacity and loss susceptibility relative to microstrip. Ridged variants have not yet been studied in the literature, however, in part because the eigenspectrum can not be obtained analytically. We thus present a semi-analytical software model with which to synthesise and analyse the cutoff spectrum in ridged Substrate Integrated Waveguide, verified by comparison with analytical solutions, where they exist, simulation in finite-element software and a physical prototype. Agreement with simulated and measured results is within 1 % in certain subsets of the parameter space and 11 % generally, and individual results are returned in times of the order of seconds. We use the model to analyse the relationship between geometry and frequency response, constructing an approximating function for the early modes which is significantly faster, such that think it can be used for first-pass optimisation. A range of optimal parameters are presented which maximise bandwidth within anticipated planar geometric constraints, and typical design scenarios are explored.

Vattenkraftens effekter på vandrande fiskarter har varit kända länge och väldigt få har de anpassningar som behövs för att vara funktionella för både upp-och nedströmsvandring för migrerande arter. Numera vet man det även finns ett behov för svagsimmande arter att använda fiskpassager och för att underlätta för dessa så har man testat olika alternativ som ska fungera för flera olika arter, bl.a. att placera substrat i form av sten eller grus i kulvertar. Vilket har visat sig vara effektivt för just svagsimmande arter genom att det sänker energikostnaden att passera och ökar attraktionen till en mer naturlig struktur. För att öka kunskapen om substrat har en effekt även vid nedströmspassage, så utfördes en experimentell studie om hur substrat påverkar nedströmspassage för mört vid avledning vid ingången till en passageöppning i en artificiell strömränna. Mörten märktes med PIT-tags och kameror placerades ut i olika vinklar för att analysera mörtens beteende. Resultatet visade att mörtar utan substrat hade en snabbare passagetid än mörtar med substrat, men även att mörtar utan substrat tog sig till flyktöppningen snabbare än mörtar med substrat. Orsaken till den långsammare passagetiden kan bero på att substratet framkallade turbulens som därmed fördröjde mörten till att undersöka flyktrännan, då inget annat beteende skiljde mellan de olika behandlingarna. Ytterligare analyser hade behövts av mörtens beteende innan flyktöppningen för att se var de blev fördröjde och då kanske få reda på orsaken. Att fortsätta undersöka fiskars beteende är viktigt för att kunna få fram fungerande alternativ på förbättringar för migrerande fiskar, det måste vara funktionellt för fler arter för att kunna gynna både miljön, naturen och vattenkraften. / The effects of hydropower on migratory fish species have been known for a long time, but very few are adapted for both upstream and downstream migration. Nowadays it is known that there is also a need for weak-swimming species to be able to use fish passages and to facilitate these, various alternatives have been tested that are functional for several different species, for instance placing substrate in the form of stone or gravel in culverts. Which has proven to be effective for weak-swimming species, because it lowers the energy cost of passing and increases the attraction to a more natural structure. In order to increase knowledge about substrate and if it also has an effect on downstream passage, an experimental study was carried out on how substrate affects downstream passage for roach through a bypass. The roach were marked with PIT-tags and cameras were placed at different angles to analyze the3roach´s behavior. The results showed that roach without substrate had a quicker passage time than roach with substrate and that roach without substrate reached the bypass faster than roach with substrate. The reason for the slower passage time may be due to the substrate causing turbulence and therefore delayed the roach to examine the bypass, as no other behavior differed between the different treatments. Further analyzes had been needed of the roach behavior before the bypass to be able to see where they were delayed and then perhaps find out what caused it. Continuing to investigate fish behavior is important in order to be able to develop alternatives to improvements for migratory fish, it must be functional for more species in order for the environment, nature and hydropower to benefit from the measure.

Electrical equivalent circuit modeling of active components is one of the most important approaches for modeling high-frequency high-power devices. Amongst the most used microwave devices, AlGaN/GaN HEMTs demonstrated their superior performance, making them highly suitable for 5G, wireless and satellite communications. Despite the remarkable performance of AlGaN/GaN HEMTs, these devices reside on substrates that invoke limitations on the operating-frequency, power-efficiency, and current dispersion phenomenon. Also, there is a limitation in present parameters extraction techniques being not able to consider both the substrate effect (Silicon, Silicon Carbide, and Diamond) and the asymmetrical GaN HEMT structure. In this thesis work, a single extrinsic parameters extraction technique using a single small-signal topology takes into account both the asymmetrical GaN HEMT structure and the different substrate types with their parasitic conduction will be developed and studied for the first time. Moreover, large-signal modeling using Quasi-Physical Zone Division technique has been applied to both GaN/D and GaN/SiC to model the isothermal-trapping free drain current, and combined with a new simple technique for comparing performance between active devices in terms of current-dispersion. The models were verified by simulating the small-signal S-parameters, large-signal IV characteristics, and single-tone load-pull. High accuracy was achieved compared to the measurement data available in the technical literature and obtained from fabricated devices.

Cadmium telluride (CdTe) is a leading thin film photovoltaic (PV) material due to its near ideal band gap of 1.45 eV, its high optical absorption coefficient and availability of various device fabrication methods. Superstrate CdTe solar cells fabricated on glass have to-date exhibited efficiencies of 16.5%. Work on substrate devices has been limited due to difficulties associated with the formation of an ohmic back contact with CdTe. The most promising approach used to-date is based on the use of an interlayer between the CdTe and a metal electrode, an approach that is believed to yield a pseudo-ohmic contact. This research investigates the use of ZnTe and Sb2Te3 as the interlayer, in the development of efficient back contacts. Excellent adhesion and minimum stress are also required of a CdTe thin film solar cell device on a flexible stainless steel (SS) foil substrate. Foil substrate curvature, flaking, delamination and adhesion as a result of compressive strain due to the coefficient of thermal expansion (CTE) mismatch between the flexible SS foil substrate and the solar cell films have been studied. A potential problem with the use of a SS foil as the substrate is the diffusion of iron (Fe), chromium (Cr) and other elemental impurities into the layers of the solar cell device structure during high temperature processing. A diffusion barrier limiting the out diffusion of these substrate elements is being investigated in this study. Silicon nitride (Si3N4) films deposited on SS foils are being investigated as the barrier layer, to reduce or inhibit the diffusion of substrate impurities into the solar cell. Thin film CdTe solar cells have been fabricated and characterized by AFM, XRD, SEM, ASTM D3359-08 tape test, current-voltage (I-V) and spectral measurements. My individual contributions to this work include the Molybdenum (Mo) development, the adhesion studies, the silicon nitride (Si3N4) barrier studies, and EDS and SEM lines measurements and analysis of substrate out-diffused impurities. The rest of my colleagues focused on the development of CdTe, CdS, ZnTe, the CdCl2 heat treatment, and other back contact interlayer materials.

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京都大学 / 0048 / 新制・課程博士 / 博士(人間・環境学) / 甲第22671号 / 人博第957号 / 新制||人||227(附属図書館) / 2020||人博||957(吉田南総合図書館) / 京都大学大学院人間・環境学研究科相関環境学専攻 / (主査)教授 川本 卓男, 教授 宮下 英明, 教授 高田 穣 / 学位規則第4条第1項該当 / Doctor of Human and Environmental Studies / Kyoto University / DFAM

Iodine is an essential nutrient for humans, which is often not ingested through food in adequate quantities. Currently, Germany is once again one of the countries in which there is an iodine deficiency in the population. Women between the ages of 20 and 40 are particularly affected, a critical situation since pregnant and lactating women have an increased iodine requirement. Iodization of table salt is a widely used prophylactic measure. However, this method is not sufficient and may become less important in the future if further dietary salt reduction occurs, as nutritionists are demanding. Alternative approaches are therefore needed to improve the supply. One of these approaches is the agronomic biofortification of food crops. In this process, iodine is applied via fertilization measures during the cultivation of the plants. This gives the plants the ability to take up the mineral, which is only available in the soil to a very limited extent. In recent years, many studies have been published on the biofortification of vegetables and cereals. Foliar fertilization measures have proven to be significantly more efficient than soil fertilization measures. Nevertheless, up to now few results are available on the biofortification of fruit crops. However, fruit is also important for a healthy diet and the iodine supply of humans can only be improved if as many iodine-rich foods as possible are available. Therefore, the aim of this work was to investigate iodine biofortification of berry and tree fruit species in more detail. In order to be able to achieve this objective, trials were performed over several years with strawberries, apple and pear trees. In addition to suitable application methods, the aim was to determine the iodine form (iodide and iodate) and the necessary iodine quantity. On the one hand, the measured iodine contents in the fruit and leaf tissue allowed conclusions to be drawn about the translocation of iodine in the plant. On the other hand, this made it possible to evaluate the basic suitability for iodine biofortification of the fruit crops investigated. Since iodine has a phytotoxic effect above a certain amount, the plant compatibility should also be tested. In addition, common household processing methods, such as washing or peeling the fruit, as well as fruit storage over several months, should provide information on the extent to which such measures could reduce the iodine content. Another study parameter was the soluble solids content, as there is evidence that iodine can affect the sugar content of fruit. Furthermore, a combined application of potassium nitrate and selenium was carried out and their influence on iodine and sugar content was investigated. Selenium is also an essential trace element, which is usually inadequately absorbed through the diet. The results of the investigations showed that it was possible, in principle, to raise the iodine content of strawberries, apples and pears to a level of 50 to 100 µg iodine per 100 g fresh mass. In the case of strawberries, however, this was only feasible if the plants were in their first year of cultivation and the iodine was applied by foliar fertilization shortly before harvest. In the 2nd and 3rd year of cultivation, the plants had a very dense canopy, which prevented direct wetting of the fruit. However, direct wetting of the fruit surface with the iodine solution is imperative, as this was the only way to achieve a reliably high iodine content in the fruit mass. Soil fertilization proved to be completely unsuitable in trials with strawberries and apple trees. The translocation of iodine after soil fertilization occurred mainly via the xylem transport into the strongly transpiring leaves and not into the fruits. In addition, compared to a foliar application, a significantly higher iodine application rate was required. Furthermore, experiments with apple trees cultivated in a plastic tunnel, protected from precipitation, showed that the iodine transfer via the phloem into the fruits was only marginal. With regard to the phytotoxic effect of iodine application, no consistent difference was observed between potassium iodide and potassium iodate. Both forms of iodine did not affect yield or average individual fruit weight. Damage to fruit was not observed in any variant. However, with increasing iodine levels, significant damage to leaves was noticeable. Apple and pear trees also showed early leaf fall. Iodide generally led to significantly higher iodine contents in the plant mass after foliar application, but this was also associated with high fluctuations. With iodate, it was possible to reliably achieve the targeted iodine content in the fruit mass of apple and pear trees with an application rate of 1.5 kg iodine per hectare and meter canopy height. Washing the fruit reduced the iodine content of strawberries by up to 30%. For apples and pears, this value was about 14% at harvest and about 12% after 3 months of storage. Peeled apples and pears showed a significantly reduced iodine content. 51% of the iodine in apples was bound in the fruit peel or the cuticular waxes. A reduction of 73% was determined for pears. Cold storage for 3 months resulted in a significant loss of iodine in parts of the apple peel. At this point, the release of volatile iodine compounds is probably the cause of the reduction. However, this would still have to be confirmed by further investigations. Iodine application had a negative effect on the soluble solids content of strawberries above a certain level. It was not possible to observe significant changes for pome fruit in the trials conducted. However, the application of potassium nitrate (alone and in combination with iodine) resulted in an increase. Iodine uptake remained unaffected by the combined application of potassium nitrate and selenium. However, it was shown that selenium has a comparable uptake and translocation pattern to iodine and that a combined biofortification with both minerals is, in principle, possible. Accordingly, apple and pear trees are well suited for biofortification with iodine by foliar fertilization. However, further trials in commercial orchards are necessary to implement this process. In the future, appropriately fortified fruit could make an important contribution to the alimentary iodine supply for humans.