The acidic, non-oxidative dissolution of galena nanocrystals has been studied using both microscopic and wet-chemical methods. The effects of particle size, shape, aggregation state, and grain proximity on dissolution rates were investigated. Nearly monodisperse galena nanocrystals with an average diameter of 14.4 nm and a truncated cubic shape were synthesized. In the dissolution experiments of dispersed nanocrystals, galena nanocrystals attached on the surface of a TEM grid were exposed to deoxygenated HCl solutions (pH 3) at 25 °C. Capping groups on nanocrystals were removed via a washing process, and chemistry of nanocrystals was examined using X-ray photoelectron spectroscopy (XPS). The evolution of the size and shape of the pre- and post-dissolution nanocrystals were studied using transmission electron microscopy (TEM), and the dissolution rate was calculated directly according to the size shrinking of galena nanocrystals. To assess the size effect, galena microcrystals (~ 3 μm) were synthesized and dissolved under similar conditions to the dispersed nanocrystals. The results showed that the nanocrystals dissolved at a surface area normalized rate of one order of magnitude faster than the microcrystals. In addition, dissolution rate is orientationdependent on a single nanocrystal. High-resolution TEM (HRTEM) images indicated the {111} and {110} faces dissolve faster than {100} faces on galena nanocrystals, rationalized by the average coordination number of ions on each of these faces. To assess the aggregation effect, dissolution experiments of aggregated galena nanocrystals were conducted using a wet-chemical method, and the results were compared with the rates of microcrystals and dispersed nanocrystals. These experiments showed that the rate of aggregated nanocrystals is in the same order of magnitude as the rate of microcrystals, but one order of magnitude smaller than that of dispersed nanocrystals. Finally, the effect of the close proximity between nanocrystals on dissolution was observed by HRTEM. Dissolution was greatly inhibited on nanocrystal surfaces that were closely adjacent (1-2nm, or less) to other nanocrystals, which is probably relevant to the slow dissolution of aggregated nanocrystals. The dissolution phenomena of galena nanocrystals observed in this study is likely important for understanding the environmental fate and behavior of nanoparticles in aquatic systems. / Ph. D.

This dissertation offers a conceptual framework capturing forecasting related activities in a formal organizational context, and it empirically assesses how and how well an organization utilizes forecasting tools and results. Specifically, a multilevel model is formulated that suggests that forecasting capabilities and forecasting processes predict forecasting effectiveness. The model is tested through a field study utilizing a qualitative and quantitative research design. The findings suggest that there are great differences in how forecasting is done among mangers within the same organization, and that in the absence of process congruency (i.e., similar procedures for similar forecasters), the use of a bottom-up approach to forecasting contributes to inconsistent forecasting results. Further, the findings suggest that when it is difficult to establish solid market information, managers often look to competitors in order to establish pseudo-estimates of supply and demand. With respect to content congruency (i.e., the imposition of higher level forecasts onto lower level entities), the dissertation examines the consequences of making decisions based on data from different levels of analyses (and with different geographic scopes).The results highlight the consequences of relying on higher level forecasts when a mismatch exists between organizational and national “footprints”. Using various economic variables to predict housing starts across levels, the analyses found disparate results for the lower level of analysis. The results also reveal great differences in the strength of the forecasting models between different levels of analysis and between different entities at the same level. Different combinations of variables contribute toward predicting the key dependent variable, housing starts, at different levels, and even between geographic markets at the same level of analysis. The findings suggest that traditional organizational forecasting performed at the national level presents decision makers with a “hit or miss” scenario when trying to predict housing demand in the local markets. The inability to generate strong forecasts utilizing the same variables in different markets appears to be problematic. Thus, a “bottoms-up” approach to the technical generation of forecasts is desirable Recommendations for both future research and practice are suggested. / Ph. D.

Biological development and progression are managed by a diverse macromolecular group called proteins. Protein structure results from a complex folding process that leads to a final active form. This protein state is susceptible to changes in the surrounding environment and an incorrect structure can be produced. Changes in the protein conformation can lead to the formation of protein aggregates. Adsorption of proteins onto surfaces is utilized in many research analyses, but is capable of irreversibly changing the protein structure and causing aggregation. Albumin is a plasma protein that adsorbs on many different surfaces because the structure easily rearranges. The structure of albumin once adsorbed has been shown to deteriorate; however, outcomes of both stabilization and aggregation have been found. A dynamic laser light scattering instrument will be utilized to measure the differences in size and determine the amount of aggregation. Our lab has developed a z-axis translating laser light scattering device (ZATLLS) that has been used to measure the sedimentation velocity of several different materials in solution. In this case, bovine serum albumin (BSA) will be adsorbed onto polystyrene particles and the particle settling velocity determined. The settling solution viscosity and density will also be ascertained, so Stoke's law can infer the average aggregate size of each experiment. BSA-coated polystyrene particles displayed a more controlled settling behavior compared to non-coated polystyrene particles. Although the BSA-coated particles had a smaller sedimentation velocity, a larger aggregate size was found due to the greater solution viscosity. Therefore, the ZATLLS instrument can be employed to measure sedimentation velocities of multiple interactions and the aggregation level inferred. Although most albumin molecules are remarkably similar, there are subtle differences in amino acid residues, length, and charge. Sedimentation velocities for human serum albumin (HSA) coated polystyrene particles and BSA-coated polystyrene particles only had a small difference. However an almost 50% higher solution viscosity was measured in BSA experiment solutions, and resulted in the slower settling of the larger aggregates compared to HSA-coated particles. Viscosity calibration curves for each albumin species were used to determine the amount of protein desorbed from the particles during the settling process. The larger solution viscosity for BSA-coated particle experiments led to a much larger degree of desorption. HSA was shown to be the more stable albumin species when adsorbed onto polystyrene particles. Temperature denaturing was performed to aid in the determination of the stability of BSA. Reversible and irreversible conformational changes in BSA were produced at 46ºC and 76ºC respectively. The solutions were cooled to room temperature before adsorption ontopolystyrene particles and the sedimentation velocities measured. A 50% difference in average viscosity between the reversibly and irreversibly changed BSA was found. This caused the larger aggregates formed in the 76ºC BSA experiments to have an almost equivalent sedimentation velocity to those in the reversibly denatured BSA experiments. Average aggregate size for reversibly denatured BSA was well within the ranges found for non-denatured BSA. In conclusion, irreversibly denatured BSA formed larger aggregates and was more likely to desorb from the polystyrene particles than reversibly changed BSA. / Master of Science

Many companies, including Strike Pharma, are developing biologicals for individualized immunotherapeutic cancer treatments. The possibility to combine a bispecific antibody with a myriad of endogenous antigenic peptides opens the doors for highly personalized therapies. Setting up and using analytical assays is key to evaluate aggregation and overcome aggregation patterns of biologicals during CMC development. The aim of this project was to assess size exclusion chromatography (SEC) as an analytical method and subsequently evaluate several drug formulations that could be suitable for subcutaneous administration of a peptide and antibody conjugate mix. The formulations were based on a 25 mM histidine buffer pH 6.0, that had been optimized for the antibody alone, with different additives. By utilizing SEC coupled to UV-detection at 280 nm, aggregates were detected and quantified. The most effective excipients were dimethyl sulfoxide, polyethylene glycol 400 and arginine. Two different peptide-tags were compared and the pTag9mer-mut2 variant was more favorable than pTag9mer-mut1 in limiting aggregate formation with highest success rates at 1.5 mg/mL protein concentrations and the fulfillment of the high molecular weight ≤ 5% criterion. Combining antibody and peptide containing pTag9mer-mut1 in a pH 9.0 histidine buffer with added arginine engendered the least aggregates compared to any pH 6.0 formulation. However, the instability of the antibody in pH 9.0 and the risk of deamidation makes this less suitable. Future considerations include changing the administration method or using pump injection strategy, which allows higher injection volumes to limit aggregation by lowering protein concentrations.

京都大学 / 新制・課程博士 / 博士(医学) / 甲第25175号 / 医博第5061号 / 新制||医||1071(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 江藤 浩之, 教授 長尾 美紀, 教授 大鶴 繁 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

Three-dimensional printing is renowned for its ability to produce complex geometries. By utilizing a pressure-driven additive manufacturing (AM) process called direct ink write (DIW) with polymer composite ink, it is possible to create parts with tailored internal microstructures that enhance surface area and particle-particle adsorption kinetics for water remediation applications. However, DIW of particle-filled systems faces challenges, particularly nozzle clogging. This paper explores the relationship between dispersion of aggregate size, torsional rheology, and the capacity to print relatively highly particle-filled systems. Various characterization methods, including torsional rheology, dynamic light scattering (DLS), and field emission scanning electron microscopy (FESEM) were employed utilizing a chitosan-graphene-titanium dioxide (CS-G-TiO2) polymer composite ink composed of TiO2 nanoparticles (1 wt.% to 25 wt.%), graphene (1 wt.%), and chitosan (5 wt.% to 9 wt.%) to evaluate the effect of ultrasonication techniques (bath vs. probe) on aggregate size. Probe-sonicated dispersions showed a more narrow monodispersed and unimodal aggregate size distribution with a primary average aggregate size of 255 nm. In contrast, bath-sonicated dispersions exhibited a moderately polydispersed, trimodal distribution with modes centered at 90 nm, 295 nm, and 5.6 μm. Non-Newtonian rheological parameters such as yield stress, complex viscosity, storage, and loss moduli were higher for the probe-sonicated CS-G-TiO2 composite ink than for the bath-sonicated CS-G-TiO2 composite ink. This increase is likely attributed to enhanced particle interactions, which allow for greater CS adsorption. These findings offer valuable insights into optimizing formulations for desired rheological properties in DIW printing. The results enable the direct ink writing of intricate geometries with high surface areas and less shape distortion, providing significant insights into processing similar multi-component slurry-based composite inks for DIW. / Master of Science / Researchers are exploring new ways to remove harmful toxins from waterbodies using 3D printing technology. By employing a specialized additive manufacturing (AM) printing process called direct ink write (DIW) and a composite ink (CS-G-TiO2) composed of chitosan (CS), graphene (G), and titanium dioxide (TiO2), it is possible to create parts with a tailored internal microstructure that allows for greater surface area and enhanced particle-particle adsorption kinetics. However, challenges remain with DIW of particle-filled systems, particularly regarding nozzle clogging. This assessment focuses on how the size of aggregates in G-TiO2 dispersions affects printability and the rheological behavior of the CS-G-TiO2 composite inks. To address these issues, different ultrasonication techniques and their effects on aggregate size were investigated, as well as the shear-thinning and yield stress behavior of the inks. These findings could be further analyzed to understand the underlying mechanism in particle aggregation and optimize the formulation for desired rheological properties for direct ink write (DIW) printing.

Understanding the differences among public transit types allows for the development of more targeted policies at both local and regional levels. Examining how the built environment (BE) influences travel behavior (Delclòs-Alió et al.) and assessing data aggregation effects around different transit station types at the local level, along with identifying key predictors of ridership across transit modes at the regional level, offers valuable insights for policy efforts. Specifically, the dissertation comprises three studies that analyze BE-travel behavior associations and data aggregation effects locally, as well as variations in key predictors of rail and bus ridership at a regional scale within the United States. The findings emphasize the unique land-use and travel behavior associations for various public transit systems within transit catchment areas, the effects of data aggregation on BE-travel behavior models, and the critical predictors of rail and bus ridership at regional levels. The first study highlights nonlinear associations between BE attributes and commuting mode share within rail and Bus Rapid Transit (BRT) catchment areas, using data from approximately 2,790 transit stations across 34 U.S. metropolitan statistical areas. Applying a random forest model, this study reveals substantial differences between rail and BRT areas, with rail catchment areas showing greater sensitivity to BE factors in reducing car dependency. BRT, however, emerges as a viable alternative for sprawling areas lacking the compact development needed to support rail systems. The second study investigates how data aggregation influences the BE-mode share relationship around 2,794 rail and BRT stations, utilizing both inferential and machine learning approaches. Findings indicate that data aggregation affects BE-mode share models regardless of the analytical method. Optimal buffer sizes for capturing BE effects and minimizing sensitivity to data aggregation were identified as 800 meters for BRT stations and 1,000 meters for rail stations. Key BE features such as employment density, jobs per household, intersection density, residential density, distance from the central business district, job accessibility (active modes) demonstrated robustness against data aggregation for both rail and BRT stations. The third study examines changes in transit ridership predictors before and after the COVID-19 pandemic across 35 U.S. metropolitan areas. Using extreme gradient boosting on data spanning January 2019 to June 2023, the study identifies a shift from internal to external factors as key drivers of ridership post-pandemic. Socioeconomic factors, gasoline prices, telecommuting, population density, employment density and polycentric development emerged as influential for bus ridership post-pandemic, while traditional factors like vehicle revenue miles, fare, transit coverage, and service areas are more important for rail ridership. Additionally, the study uncovers unique threshold and interaction effects in the post-pandemic period, including positive interactions between African American population proportions and poverty rates for bus ridership, carless households and gasoline prices for bus ridership, and between VRM and polycentricity for rail ridership. This dissertation provides insights into the complex dynamics between BE, transit types, and travel behavior, offering valuable implications for urban transportation planning and policy development at multiple levels. / Doctor of Philosophy / This research explores how different aspects of urban design impact public transit use and helps identify what drives ridership on different types of transit. By studying connections between urban layouts and travel habits around transit stations, the findings offer guidance for creating tailored local and regional transit policies. Specifically, the research looks at three key areas: how built environments relate to travel choices locally, how data processing methods influence results, and what factors influence bus and rail ridership across U.S. cities. The first part reveals that the design of areas around rail and Bus Rapid Transit (BRT) stations affects travel patterns in unique ways. Rail stations tend to decrease car use in well-developed areas, while BRT stations work better in sprawling urban settings, where compact rail development isn't feasible. The second part shows that the way data is organized can change how we understand the link between urban form and transit use. For example, analyzing a broader area (up to 1,000 meters) around rail stations captures the effect of local design better, while an 800-meter radius is optimal for BRT. Certain features, like job density and proximity to the city center, consistently predict transit use, regardless of the data scale. Finally, the third part examines changes in what drives transit ridership since the COVID-19 pandemic. While pre-pandemic ridership was mostly influenced by operational factors like service coverage, post-pandemic ridership is more affected by external factors like gas prices and remote work trends. Unique patterns also emerge, such as links between certain demographics and bus ridership and between economic factors and rail use. Overall, this study helps planners and policymakers understand the unique needs of rail and bus systems, supporting strategies to make public transit more effective and responsive to community needs.

LTE heterogeneous wireless networks promise significant increase in data rates and improved coverage through (i) the deployment of relays and cell densification, (ii) carrier aggregation to enhance bandwidth usage and (iii) by enabling nodes to have dual connectivity. These emerging cellular networks are complex and large systems which are difficult to optimize with centralized control and where mobiles need to balance spectral efficiency, power consumption and fairness constraints. In this dissertation we focus on how decentralized and autonomous mobiles in multihop cellular systems can optimize their own local objectives by taking into account end-to-end or network-wide conditions. We propose several link-adaptive schemes where nodes can adjust their transmit power, aggregate carriers and select points of access to the network (relays and/or macrocell base stations) autonomously, based on both local and global conditions. Under our approach, this is achieved by disseminating the dynamic congestion level in the backhaul links of the points of access. As nodes adapt locally, the congestion levels in the backhaul links can change, which can in turn induce them to also change their adaptation objectives. We show that under our schemes, even with this dynamic congestion feedback, nodes can distributedly converge to a stable selection of transmit power levels and points of access. We also analytically derive the transmit power levels at the equilibrium points for certain cases. Moreover, through numerical results we show that the corresponding system throughput is significantly higher than when nodes adapt greedily following traditional link layer optimization objectives. Given the growing data rate demand, increasing system complexity and the difficulty of implementing centralized cross-layer optimization frameworks, our work simplifies resource allocation in heterogeneous cellular systems. Our work can be extended to any multihop wireless system where the backhaul link capacity is limited and feedback on the dynamic congestion levels at the access points is available. / Ph. D.

Pheromone lures and trap crops are appealing pest management tools that use insect and/or plant volatiles to reduce pest populations on crops of interest. Generating pheromone-emitting trap plants may allow for a continuing and highly-specific attraction of insect pests without repeated and costly application of synthetic pheromones. These trap plants may also be used to develop area-wide pest management strategies. As a proof-of-principle study we tested the possibility of producing the pheromone of the crucifer flea beetle Phyllotreta cruciferae in transgenic plants. P. cruciferae is an important pest of Brassica crops. In the presence of a host plant, males emit an aggregation pheromone, which attracts both males and females. Himachaladiene, a sesquiterpene, has been identified as a key component of the aggregation pheromone of P. cruciferae. In a close relative, Phyllotreta striolata, the compound is synthesized by a two-step pathway with an isoprenyl diphosphate synthase (PsIDS3) making (Z,E)-farnesyl diphosphate (FPP), which is converted by a terpene synthase (PsTPS1) to himachaladiene. Transient transformation of N. benthamiana with PsIDS3-TPS1 co-localized to the plastid resulted in the emission of himachaladiene and other known PsTPS1 products. Daily emissions of himachaladiene were approximately 1 µg per plant, which is six-fold higher than emissions from individual male flea beetles. Stable transformation of Arabidopsis thaliana with the same vector construct resulted in transgenic plants that expressed PsTPS1 and PsIDS3 transcripts, but no himachaladiene or other PsTPS1 products were present in volatile collections or leaf extracts of these plants. Moreover, no PsTPS1 enzyme activity was observed, indicating that post-transcriptional/translational effects prevent proper expression or targeting of functional PsIDS3 and/or PsTPS1 proteins in A. thaliana. Overall, this study demonstrates that the key component of the P. cruciferae aggregation pheromone, himachaladiene, can be transiently produced and emitted in a plant system at rates that are biologically relevant for insect attraction. However, further work is required for the stable production of the pheromone in plants. In addition, preliminary results are presented for the development of simple two-choice arenas that may allow for assessment of the movement of beetles toward host plant leaf tissue. This work can inform future efforts in developing methods for the economic production of himachaladiene in a plant system or the establishment of transgenic plants for the production and deployment of himachaladiene in a field setting. / Master of Science / The crucifer flea beetle is an important pest of vegetable and oilseed Brassica crops such as broccoli, cabbage and canola. Feeding by beetles has its greatest impact on crop health and yield in the early spring, when adult beetles emerge from overwintering sites and feed on newly- emerging Brassica seedlings. Currently these insects are controlled using broad spectrum insecticides. A general awareness of the negative aspects of insecticides drives the search for alternative pest management strategies that could diversify our management strategies and reduce reliance on insecticides. Previous work has found that the crucifer flea beetle navigates to its host plants, in part, through plant-emitted volatiles. After locating the plant host, males emit a volatile aggregation pheromone that when blended with host plant volatiles increases attraction. Here work towards the development of a specialized trap crop is presented. Plants were engineered to emit a key component of the crucifer flea beetle aggregation pheromone. In an engineered non-host plant, Nicotiana benthamiana, transient production of the aggregation pheromone was established. However, in an engineered Brassica plant, Arabidopsis thaliana, no aggregation pheromone was detected despite evidence of the presence and expression of the required biosynthetic genes for its production. A discussion on alternative engineering strategies for A. thaliana is presented. In addition, preliminary results are presented for the development of a simple behavior assay to assess the attraction of beetles toward different smells. This work can inform future efforts aimed at developing methods for the economic production of the aggregation pheromone in a plant system or the establishment of plants for the production and deployment of the aggregation pheromone in a field setting.

Harlequin bugs are orange and black aggregation pheromone emitting stink bug pests, specifically of cole crops such as kale, broccoli and collards. This nearly loyal crop preference makes an interesting challenge for trapping them and helping farmers predict pest severity. Harlequin bugs can be found in much of North America, and are a serious problem in the southeastern United States. Presumably their persistence into northern regions is limited by extreme winters. In 2014 and 2015 the arctic polar vortex extended into mid-latitudes bringing a blanket of sustained sub-freezing temperatures to much of the United States. We used these events to determine effects of extreme winter weather on harlequin bug survival. In both years we observed nearly identical low temperatures of -15oC and this linked to high (80-96%) harlequin bug mortality. In the lab we measured exact lethal freezing temperatures in harlequin bugs (i.e. supercooling points) to see if a physiological metric could be used to predict overwinter survival. Harlequin bug adults froze and died at -10.4oC, and similarly, their larger juvenile stages freeze at -11.0oC. Freshly hatched harlequin bugs and unhatched eggs froze at considerably lower temperatures with eggs forming ice crystals at -23.2oC and recent hatches at -21.6oC. Now with an understanding of how harlequin bugs likely survive winter extreme, we can then work on developing a trap to tally their populations in the spring and predict summer and fall pest severity. In the lab and field, harlequin bug adults and large nymphs were more likely found on green and black colors, and statistically less frequently on yellow, white, purple or red colors with the exception of adult females, which were most attracted to red and green in the lab, but green and black in the field. To increase harlequin bug attraction to and termination at traps square corrugated plastic panels were wrapped with an insecticide netting and baited with harlequin bug aggregation pheromone, murgantiol. Bugs were effectively drawn to the panels, with green panels having significantly more dead harlequin bugs and fewer dead beneficial lady beetles (Coleoptera: Coccinellidae) at their base than yellow panels. Thus, green was chosen as the ideal trap color to use for another field experiment that evaluated three trap types -- a corrugated plastic square panel, pyramidal trap, and ramp trap -- each with three lure treatments, murgantiol alone or murgantiol plus a low or high rate of mustard oil. More bugs were killed with the pyramidal trap than with the panel trap or the ramp trap, and more bugs were killed at traps containing murgantiol combined with benzyl isothiocyanate than at those with murgantiol alone. This research demonstrated that with the proper visual elements and odors, harlequin bugs can be drawn to traps and effectively killed after contact with insecticide-incorporated netting. / MSLFS / Harlequin bugs are orange and black aggregation pheromone emitting stink bug pests, specifically of cole crops such as kale, broccoli and collards. This nearly loyal crop preference makes an interesting challenge for trapping them and helping farmers predict pest severity. Harlequin bugs can be found in much of North America, and are a serious problem in the southeastern United States. Presumably their persistence into northern regions is limited by extreme winters. In 2014 and 2015 the arctic polar vortex extended into mid-latitudes bringing a blanket of sustained sub-freezing temperatures to much of the United States. We used these events to determine effects of extreme winter weather on harlequin bug survival. In both years we observed nearly identical low temperatures of -15℃ and this linked to high (80-96%) harlequin bug mortality. In the lab we measured exact lethal freezing temperatures in harlequin bugs (i.e. supercooling points) to see if a physiological metric could be used to predict overwinter survival. Harlequin bug adults froze and died at -10.4℃, and similarly, their larger juvenile stages freeze at -11.0℃. Freshly hatched harlequin bugs and unhatched eggs froze at considerably lower temperatures with eggs forming ice crystals at -23.2℃ and recent hatches at -21.6℃. Now with an understanding of how harlequin bugs likely survive winter extreme, we can then work on developing a trap to tally their populations in the spring and predict summer and fall pest severity. In the lab and field, harlequin bug adults and large nymphs were more likely found on green and black colors, and statistically less frequently on yellow, white, purple or red colors with the exception of adult females, which were most attracted to red and green in the lab, but green and black in the field. To increase harlequin bug attraction to and termination at traps square corrugated plastic panels were wrapped with an insecticide netting and baited with harlequin bug aggregation pheromone, murgantiol. Bugs were effectively drawn to the panels, with green panels having significantly more dead harlequin bugs and fewer dead beneficial lady beetles (Coleoptera: Coccinellidae) at their base than yellow panels. Thus, green was chosen as the ideal trap color to use for another field experiment that evaluated three trap types – a corrugated plastic square panel, pyramidal trap, and ramp trap – each with three lure treatments, murgantiol alone or murgantiol plus a low or high rate of mustard oil. More bugs were killed with the pyramidal trap than with the panel trap or the ramp trap, and more bugs were killed at traps containing murgantiol combined with benzyl isothiocyanate than at those with murgantiol alone. This research demonstrated that with the proper visual elements and odors, harlequin bugs can be drawn to traps and effectively killed after contact with insecticide-incorporated netting.