京都大学 / 新制・論文博士 / 博士(農学) / 乙第13413号 / 論農博第2896号 / 新制||農||1085(附属図書館) / 学位論文||R3||N5323(農学部図書室) / 京都大学大学院農学研究科農学専攻 / (主査)教授 松村 康生, 教授 白岩 立彦, 教授 丸山 伸之 / 学位規則第4条第2項該当 / Doctor of Agricultural Science / Kyoto University / DGAM

This thesis explores the evaporation kinetics of various polymer-solvent and binary solvent mixtures to explore possible connections between the solutions properties and their evaporation process. By looking at the evaporation of polymer-solutions and binary-solvent solutions, through the change in weight as the solvent evaporates and the evaporation rate of the evaporation process, potential connections could be found. The results indicate that the presence of polymers influence the solvent evaporation, with polystyrene (PS) generally accelerating and polymethyl methacrylate (PMMA) either decelerating or having minimal impact on evaporation rates. Binary solvent mixtures exhibited non-proportional increases in evaporation rates, suggesting complex intermolecular interactions, but no apparent patterns between their properties and deviation in the evaporation process. This would need further research to find possible connections to be able to predict the evaporation process. But these findings highlight the importance of understanding polymer-solvent compatibility and evaporation dynamics to enhance performance and to identify environmentally friendly solvents for organic photovoltaic (OPV) cell fabrication. / Detta examensarbete undersöker avdunstningskinetiken hos olika polymer-lösningsmedel och binära lösningsmedelsblandningar för att utforska möjliga samband mellan lösningarnas egenskaper och deras avdunstningsprocess. Genom att studera avdunstningen av polymer-lösningar och binära lösningsmedelslösningar, genom förändringen i vikt när lösningsmedlet avdunstar och avdunstningshastigheten, kan potentiella samband identifieras. Resultaten indikerar att närvaron av polymerer påverkar lösningsmedlets avdunstning, där polystyren (PS) generellt accelererar och polymetylmetakrylat (PMMA) antingen decelererar eller har minimal inverkan på avdunstningshastigheterna. Binära lösningsmedelsblandningar visade icke-proportionella ökningar i avdunstningstider, vilket tyder på komplexa intermolekylära interaktioner, men inga tydliga mönster mellan deras egenskaper och avvikelser i avdunstningsprocessen kunde identifieras. Ytterligare forskning behövs för att finna möjliga samband för att kunna förutsäga avdunstningsprocessen. Dessa fynd understryker vikten av att förstå polymer-lösningsmedelskompatibilitet och avdunstningsdynamik för att förbättra effektiviteten och kunna identifiera miljövänliga lösningsmedel för tillverkning av organiska solceller (OPV).

The objective of this research work was to understand the molecular mechanism of gas transport through amorphous glassy polymers. Especially, emphasis was placed on determining whether or not gas transport in amorphous glassy polymers is directly correlated with the free volume content. Free volume arguments are indeed commonly used to explain the gas transport process. The gas transport properties of bisphenol-A polycarbonate films were examined as a function of the cooling rate, physical aging, and orientation. Such conditions affect the free volume content and its size and shape distribution. Results obtained from permeation experiments were accompanied with dynamic mechanical and density measurements. The experimental results suggest that the diffusion coefficient of small gas molecules in glassy polycarbonate is influenced by the local dynamics or mobility of the polymer chains rather than by the overall free volume content. Indeed, the diffusion coefficient of nitrogen for instance was reduced in fast-cooled samples, despite of the fact that those samples possessed a greater overall free volume content. Fast cooling rates may generate highly restricted conformations which hinder local motions, and therefore tend to increase the activation energy of diffusion. As expected, the greater the free volume content, the greater was the solubility coefficient. The increase in the polymer relaxation times with aging time is believed to restrict the local chain motions, leading to enhanced activation energies of diffusion, and therefore to reduced diffusion coefficients. The change in the solubility coefficients with physical aging revealed that the aging process might not affect all the cavity sizes in polycarbonate equally. According to free volume arguments, one would anticipate that the physical aging of fast-cooled samples (which possess more free volume) should be enhanced compared to that of slowly-cooled samples. Quite interestingly, the decrease in the diffusion coefficient with aging was found to occur much slower in fast-cooled samples, despite of the higher initial free volume content. In contrast, properties directly related to the free volume content, such as density or isothermal DMTA measurements actually showed a greater aging rate in the sample containing the greatest amount of free volume. Slow-cooled samples that are in a low energy conformational state may loose their internal degrees of freedom more rapidly, due to the closer interchain packing and the possibly restricted segmental motions. Studies dealing with orientation and gas transport were complicated by several factors. For instance the fact that the permeation experiments were performed perpendicularly to the orientation of the chains and not along the orientation axis limited the sensitivity of the gas transport properties to orientation. This work points out that dynamic rather than static models should be developed to predict the gas transport phenomenon. / Ph. D.

In this project, we have designed and synthesized a new series of long-chain, water-soluble, dendritic, anionic amphiphiles [3CAmn, RCONHC(CH₂CH₂COOH)₃, R= CnH2n+1] to alleviate the low aqueous solubility of fatty acids. The dendritictricarboxlyato headgroup improves aqueous solubility and allows us to measure the intrinsic biological activity of our amphiphiles without the potential hindrance of low aqueous solubility. The aqueous solubilities of the anionic amphiphiles have been measured and were vastly higher than that of fatty acids. For example, 3CAm17 (1700 μM at pH 7.2) has much better aqueous solubility than the C₁₈ fatty acid analog (<<1 micromol at pH 7.4). Following the determination of aqueous solubility, both anionic and nonionic amphiphiles were tested against a wide variety of microorganisms. The anionic amphiphiles were mostly active against Candida albicans (4.4 microgram/mL), Saccharomyces cerevisiae (4.4 μg/mL), and Mycobacterium smegmatis (18 microgram/mL) and exhibited modest activity against both Gram-negative (71–280 microgram/mL) and Gram-positive bacteria (36– >6300 microgram/mL). With the exception of Neisseria gonorrhoeae (9.8 microgram/mL), the nonionic amphiphiles were mostly minimally active or inactive against Gram-negative bacteria (630–5000 microgram/mL). The nonionic amphiphiles were similarly inactive against fungi (625–5000 microgram/mL). However, the nonionic amphiphiles exhibited good activity against M. smegmatis (20 microgram/mL) and exhibited the best activity against Grampositive bacteria, such as MRSA (22 microgram/mL), Staphylococcus aureus (20 microgram/mL), and Micrococcus luteus (20 microgram/mL). The anionic and nonionic amphiphiles were also tested for possible spermicidal and anti-human immunodefiency virus (HIV) activity. The anionic amphiphiles exhibited anti-HIV activity (EC₅₀, 73–340 microgram/mL), but lacked spermicidal activity. The series had comparable anti-HIV activity to the commercial product N-9 (80 microgram/mL). Except 3CAm13, all anionic amphiphiles (1.4–4) had better selectivity indices than that of N-9 (0.9). The nonionic amphiphiles exhibited both anti-HIV (44–67 microgram/mL) and spermicidal activity (226–2000 microgram/mL). The nonionic amphiphile were more spermicidal and antiviral than Nonoxynol-9. In addition to biological activity, we determined whether the anionic amphiphiles could be utilized as corrosion inhibitors or ore flotation enhancers. The anionic amphiphiles formed stable thin films on silver oxide that were resistant to ethanol washings. We also measured the water contact angles of the anionic amphiphiles on mineral surfaces [apatite (95°), calcite (92°)]. / Ph. D.

Many previous studies of biological activity in a homologous series of amphiphiles have shown a cut-off effect, where the biological activity increases with an increase in chain length, after which the activity plateaus or weakens. One factor suspected to cause this problem is solubility issues. We have designed several series of very hydrophobic, water-soluble amphiphiles to overcome this problem. Three homologous series containing mobile hydrophobic moieties and two series of epimers containing rigid cholestane moieties have been synthesized; the hydrophobic moiety is connected to the first-generation, Newkome-type dendron via a ureido linker. We have demonstrated that as tris(triethanolammonium) salts, these amphiphiles show excellent solubility in water. The solubilities in aqueous triethanolamine solution of the three series containing mobile hydrophobic moieties are 19,500 to 25,700 μM depending on the formula weight of the homolog, while those containing rigid cholestane moieties are 18,900 and 17,400 μM. Having eliminated the solubility issue, the antimicrobial activity against a broad spectrum of microorganisms has been screened. We have demonstrated that the antimicrobial activity depends on the amphiphile-series, species, chain-length, or epimer specificities, as well as hydrophobicity. The one-tailed, tri-carboxylato amphiphiles are generally better than the other series, with two exceptions. First, the two-tailed tri-carboxylato amphiphiles, <b>3CUr1(11)₂</b> and <b>3CUr1(12)₂</b>, are more active against <i>Cryptococcus neoformans</i>; in fact, both amphiphiles (MICs are 6.9 and 7.2 μM, respectively) are considered to display good antifungal activity. Second, amphiphile <b>3CUr-β-cholestane</b>, whose MIC is 27 μM, is more active against <i>Staphylococcus aureus</i>. Overall, these new tri-carboxylato amphiphiles only exhibit moderate activity with two promising leads. Furthermore, we have demonstrated the intrinsic activity (MIC₀) of the one-tailed, tri-carboxylato amphiphile series (<b>3CUrn</b>) against <i>Mycobacterium smegmatis</i>. All the MIC₀s observed are at least 8-fold lower than the corresponding CMCs. Amphiphile <b>3CUr16</b> is the most active; the MIC₀ is 100-fold smaller than the CMC. With this consideration, we have suggested that the mechanism of action of the antimycobacterial activity in amphiphile <b>3CUr16</b> is not related to detergency. / Ph. D.

M.S.

This thesis reports an investigation of hydroxypropylmethylcellulose (HPMC) as a new solid-surface room-temperature phosphorescence (SSRTP) sample matrix. The high background phosphorescence originating from filter paper substrates can interfere with the detection and quantitation of trace-level analytes. High-purity grades of HPMC were investigated as SSRTP substrates in an attempt to overcome this limitation. When compared directly to filter paper, HPMC allows the spectroscopist to achieve greater sensitivity, lower limits of detection (LOD), and lower limits of quantitation (LOQ) for certain phosphor/heavy-atom combinations since SSRTP signal intensities are stronger. For example, the determination of the analytical figures of merit for a naphthalene/sodium iodide/HPMC system resulted in a calibration sensitivity of 2.79, LOD of 4 ppm (3 ng), and LOQ of 14 ppm (11 ng). Corresponding investigations of a naphthalene/sodium iodide/filter paper system produced a calibration sensitivity of 0.326, LOD of 33 ppm (26 ng), and LOQ of 109 ppm (86 ng). Extended purging with dry-nitrogen gas yields improved sensitivities, lower LOD's, and lower LOQ's in HPMC matrices when LOD and LOQ are calculated according to the IUPAC guidelines.To test the universality of HPMC, qualitative SSRTP spectra were obtained for a wide variety of probe phosphors offering different molecular sizes, shapes, and chemical functionalities. Suitable spectra were obtained for the following model polycyclic aromatic hydrocarbons (PAHs): naphthalene, p-aminobenzoic acid, acenaphthene, phenanthrene, 2-naphthoic acid, 2-naphthol, salicylic acid, and triphenylene.Filter paper and HPMC substrates are inherently anisotropic, non-heterogeneous media. Since this deficiency cannot be addressed experimentally, a robust statistical method is examined for the detection of questionable SSRTP data points and the deletion of outlying observations. If discordant observations are discarded, relative standard deviations are typically reduced to less than 10% for most SSRTP data sets. Robust techniques for outlier identification are superior to traditional methods since they operate at a high level of efficiency and are immune to masking effects.The process of selecting a suitable sample support material often involves considerable trial-and-error on the part of the analyst. A mathematical model based on Hansen's cohesion parameter theory is developed to predict favorable phosphor-substrate attraction and interactions. The results of investigations using naphthalene as a probe phosphor and sodium iodide as an external heavy-atom enhancer support the cohesion parameter model.This document includes a thorough description of the fundamental principles of phosphorimetry and provides a detailed analysis of the theoretical and practical concerns associated with performing SSRTP. In order to better understand the properties of both filter paper and HPMC, a chapter is devoted to the discussion of the cellulose biopolymer. Experimental results and interpretations are presented and suggestions for future investigations are provided. Together, these results provide a framework that will support additional advancements in the field of solid-surface room-temperature phosphorescence spectroscopy. / Ph. D.

Properties of both chemical contaminants and polymers can impact contaminant diffusivity and solubility in new and aged polyethylene materials for pipes and geomembranes. Diffusivity, solubility, polymer and chemical properties were measured for thirteen contaminants and six polyethylene materials that were new and/or aged in chlorinated water. Tree regression was used to select variables, and linear regression was used to develop predictive equations for contaminant diffusivity and solubility in polyethylene. Organic contaminant properties had greater predictive capability than polyethylene properties. Model coefficients significantly changed between new materials to chlorine-aged materials, indicating changes of polyethylene properties impact the interaction between contaminants and polymers. The metallic flavor of copper in drinking water influences the taste of water and can cause the taste problems for water utilities. The mechanism of metallic flavor caused by these metals is related to free or soluble ions. Free copper concentrations were measured at different pH in diluted artificial saliva using a cupric ion selective electrode. Three major proteins in human saliva: α-amylase, mucin and lactoferrin, were added in the artificial saliva and the impacts on the chemical speciation of copper were analyzed. Inorganic saliva components, typically phosphate, carbonate and hydroxide combined with copper and greatly influenced the levels of free copper in the oral cavity. Proteins such as α-amylase, mucin and lactoferrin also impacted the chemical speciation of copper, with different affinity to copper. Mucin had the greatest affinity with copper than α-amylase. / Master of Science

Natamycin is an antimycotic with very low water solubility and extremely high photosensitivity, which is used to extend the shelf life of shredded cheese products. The objectives of this research are: (a) to find a new delivery system for natamycin, which increases its aqueous solubility and (b) to increase the chemical stability of natamycin so that it has a prolonged antifungal effect on the surface of the shredded cheese. Molecular inclusion complexes of natamycin were formed with β-, hydroxypropyl β-, and γ- cyclodextrins (CDs) which allowed large increases in aqueous solubility without the use of organic co-solvents or surfactants. The water solubility of natamycin was increased 16-fold, 73- fold, and 152-fold with β-CD, γ-CD, and hydroxypropyl β-CD, respectively. The natamycin:CD inclusion complexes resulted in nearly equivalent in vitro antifungal activity as natamycin in its free state. Nuclear magnetic resonance (NMR) was utilized to prove the formation of true inclusion complexes. 1H NMR shift titrations of N-(3 -N-dimethylaminosuccimido) natamycin with β- and γ-CDs enabled determination of the stoichiometry of both complexes as 1:1. Aqueous solutions of natamycin (20 mg/L) were found by quantitative HPLC to be completely degraded after 24 hours of exposure to 1000 lux fluorescent lighting at 4 °C. After 14 days of storage in darkness at 4 °C, 92.2% of natamycin remained in active form. Aqueous solutions of natamycin:β-CD complex and natamycin:γ-CD complex were significantly more stable (p < 0.05) than natamycin in its free state when stored in darkness at 4 °C. Clear poly(ethylene terephthalate) packaging with an ultraviolet light absorber allowed 85.0% natamycin to remain after 14 days of storage under 1000 lux fluorescent lighting at 4 °C. Such dramatic increases in water solubility and light stability will enable natamycin to function as a more effective antimycotic in the food industry. / Master of Science

Yes / In this paper, a dynamic model of fouling is presented to predict the crystallization of calcium carbonate and magnesium hydroxide inside the condenser tubes of Once-Through Multistage Flash (MSF-OT) desalination process. The model considers the combination of kinetic and mass diffusion rates taking into account the effect of temperature, velocity and salinity of the seawater. The equations for seawater carbonate system are used to calculate the concentration of the seawater species. The effects of salinity and temperature on the solubility of calcium carbonate and magnesium hydroxide are also considered. The results reveal an increase in the fouling inside the tubes caused by crystallization of CaCO3 and Mg(OH)2 with increase in the stage temperature. The intake seawater temperature and the Top Brine Temperature (TBT) are varied to investigate their impact on the fouling process. The results show that the (TBT) has greater impact than the seawater temperature on increasing the fouling.