The process of massive star formation greatly influences its surroundings through their outflows, vast UV output and shocks from their supernova death. They form at great distances from the Earth, enshrouded by dust and gas and have relatively short lifetimes. Astrophysical masers which form in these environments may act as locators of the star forming regions. The aim of this thesis is to study massive star formation using masers to probe these regions. The three main masers used in this thesis are the Class I and Class II methanol masers and the 6035 MHz ex-OH maser. The methanol masers are divided into two groups, Class I and Class II, based on their distance from a central source. The Class I masers are separated 1-2 pc from a central source, the central source is the star forming region. The Class II masers are associated close to a star forming source. They are often associated with a 6035 MHz ex-OH maser. The 6035 MHz ex-OH masers are less common than the 6668 MHz Class I methanol masers. They are often found at sites of the 6668 MHz Class I masers and 1665/7 MHz OH masers. This thesis presents two maser surveys, the Methanol Multibeam (MMB) survey and the Class I survey. The MMB survey is currently surveying the entire Galactic Plane for the 6668 MHz Class II methanol maser and the 6035 MHz ex-OH maser. Over 60\% of the survey in the Southern hemisphere is now complete using the Parkes telescope. Over 900 6668 MHz Class I methanol masers and 110 6035 MHz ex-OH masers have been detected, with all of these masers pinpoint the location of newly forming high mass stars. Follow up observations to determine the precise locations of the 6668 MHz methanol and 6035 MHz ex-OH masers are currently underway. The first ever unbiased Class I survey has observed 1 sq degree of the Galactic Plane for the 44 GHz Class I methanol masers using the Mopra telescope in Australia. The 44 GHz Class II methanol masers are hypothesised to be associated with the outflows of high mass stellar objects. The Class I survey has detected 25 44 GHz methanol masers, with 23 being new detections. A smaller survey for 36 GHz Class I masers was also conducted using the Mopra telescope centered on the region with the highest population of 44 GHz Class I masers.

Background: Methanol poisoning survivors in their lives seen big changes, especially in sphere of quality of life. Aims: The aim of this thesis is to analyze changes in the quality of life for survivors after a methanol poisoning that took place in a large affair in 2012-2013, when there were many tens of poisoning. Sample and Methods: A cohort of 47 patients, 40 men and 7 women out of ten regions of the Czech Republic, who survived poisoning by methanol in 2012-2013. For the purpose of the research was elected standardized questionnaire WHOQOL-100, which was subsequently processed in MS Excel. Results: The research has confirmed that the quality of life has deteriorated after a methane affair. The patient said they had the biggest problems in the area of finance; Mobility; Energy and fatigue; Sleep and rest; Perception of body and appearance; Everyday activities. Highest values were recorded in the areas of Experience; Thinking, learning, memory and concentration. In conclusion, low value items are predominant and no maximum value of 20 has been recorded. Conclusion: The presented results are a clear indicator that the quality of life has deteriorated in the case of the surviving metallurgical case in the Czech Republic. Key words: quality of life, poisoning, methanol, survivors.

Carbon dioxide levels in atmosphere are linked with a number of adverse environmental impacts including climate change. CO2 utilization is one of the available technologies to reduce CO2 emissions released into atmosphere by its conversion into value added products. Hydrogenation of CO2 into hydrocarbons (with methanol being an intermediate) can be achieved in a single-pot using bi-functional catalysis system composed of metal/metal-oxide and zeolite. In this study, activated novel indium cobalt (InCo) and zeolite beta samples (BEA) were used for the conversion of CO2 into a hydrocarbon mixture rich of iso-paraffins via methanol in a single pot. The objective was to investigate the effect of zeolite beta acidity (represented by SiO2/Al2O3 ratio) and the configuration of the reactor on the overall performance of the above mentioned bi-functional system. Three samples of zeolite beta with different SiO2/Al2O3 ratios were synthesized in-house (Beta-20, Beta-100 and Beta-300) and used along with commercial beta as methanol to hydrocarbons catalysts. XRD patterns of the synthesized samples showed that all of the obtained samples are zeolite beta with high crystallinity. Adsorption-desorption isotherms of the studied zeolites revealed micro-mesoporosity of the samples. Analysis of SEM images suggests that the particles of the studied samples are of a similar range of size (100-200 nm). Each zeolite sample was used to fill two reactor configurations: dual bed and mixed bed. Samples were tested at a temperature of 300 oC, a pressure of 50 bar and CO2:H2 ratio of 1:4 except for Beta-100 sample which was tested at a CO2:H2 ratio of 1:3. CO2 conversion is a characteristic of the methanol synthesis catalyst (InCo) and it ranged between 15% to 20% for all cases. Dimethyl ether (DME) generation in dual bed configuration was much faster and at much higher rates than in mixed bed configuration for all tested samples, indicating that mixed bed configuration is more stable for this particular system. Heavier hydrocarbons (C6 and C7) are generated in higher amounts over low acidic zeolite beta than over beta of high acidity. More acidic zeolite beta, however, was found to be more stable than beta of less acidity.

Metal nanoparticles have been widely used for many catalytic and electrocatalytic applications due to their larger surface area-to-volume ratios and higher densities of active sites compared to bulk materials. This has resulted in much interest in understanding the electrocatalytic behavior of metal nanoparticles with respect to their structure. However, most research on this topic has employed collections of nanoparticles. Due to difficulties in controlling and characterizing particle loading and interparticle distance in nanoparticle ensembles, single nanoparticles studies have recently become a topic of great interest. In this study, a soft nitriding technique was applied to chemical vapor-deposited carbon ultramicroelectrodes (UMEs) in order to immobilize ligand-free AuNPs onto the carbon substrate. The feasibility of this method is geared toward studying the properties of single AuNPs immobilized onto carbon nanoelectrodes. The ligand-free AuNPs immobilized onto the nitrided carbon UMEs were highly electrocatalytic toward methanol oxidation.

Emissions of CO$_2$ largely contribute to global warming. Carbon dioxide can be captured and used to produce value-added chemicals. This thesis focuses on bioelectrocatalysis as a green and sustainable approach. Our aim was to perform conversion of CO$_2$ to methanol via a multi-enzymatic cascade. However, for reactions involving oxidoreductases, ß-NAD is required as a cofactor. Its use in stoichiometric amounts is unprofitable. We address the issue by employing electrochemical regeneration of the cofactor. For the cascade, we expressed and purified formate dehydrogenase, formaldehyde dehydrogenase and alcohol dehydrogenase. Enzymes activity was tested and found to be low for two enzymes. A reliable method to detect methanol via headspace gas chromatography with a flame ionization detector was developed. We tested the cascade with employed in situ electrochemical cofactor regeneration. After two and a half hours of the reaction 4 µmol methanol were detected. Further research is needed to optimize the setup.

Problems presented in this paper concern the chemical equilibrium of methyl alcohol, formic acid, and methyl formate when combined.

The green production of formic acid and utilization of methanol over heterogeneous catalysis system were investigated in this study. The heterogeneous catalysts are widely used in the chemical industry. They offer high stability and reusability which can enhance the production ability and lower the production cost, it can be considered as the sustainable energy solution for the future. In this work, we demonstrated several different heterogeneous catalysts for sustainable formic acid production and methanol utilization, including the heteropoly acid supported mesoporous silica catalysts and multi-function mixed metal oxide catalysts. Detailed characterizations of the final products were carried out by N2 adsorption and desorption, XRD, HR-TEM, SEM, ICP-OES, XANES, NH3- TPD, Raman spectroscopy, and FTIR to identify the chemical properties and physical properties of the catalysts. We obtained 60 % glycerol conversion and 30 % formic acid selectivity with at least 3 rounds of usages in batch system over PV1Mo/SBA-15-p-DS catalyst. Moreover, the continuous methyl formate production with significantly high formation rate (16.7) has been achieved via our CuMgO-based catalysts, and the best Cu5MgO5 catalyst gives more than 80 % methanol conversion with constant selectivity to methyl formate even after 4 catalytic test (more than 200 h), revealing their potential for industrialization. For the methanol utilization reaction, the methanol homocoupling to form dimethoxymethane (DMM) has been investigated. The redox and acidic properties of catalysts both play a critical role in this reaction and the related to different product. The supported V2O5 catalyst achieves the best catalytic performance (62.1 % conversion and 85.6 % DMM selectivity) with a Ce/Al specific ratio of 1. This research not only provided the efficient catalysts for numerous application with high activity, but also discovered the relation between the catalytic performance and the nature of the materials. These findings might further help the researcher to solve the global environmental and energy issues in the near future.

Enzymes can catalyze reactions with high selectivity under mild conditions, and are therefore especially suited for the upgrading of C1 feedstocks into value-added products. Linear carbon ligation routes are of particular interest due to their simplicity and potential for high carbon efficiencies. A linear carbon fixation pathway can be constructed using a combination of NADH-dependent oxidoreductase enzymes and a formaldehyde carboligation enzyme, through which CO₂ is upgraded into C₂ and C₃ products. The stoichiometric NADH requirement imposed by the oxidoreductase enzymes and the poor performance of two core pathway enzymes (formaldehyde dehydrogenase and formolase) are the main obstacles to the efficient application of this linear carbon fixation pathway. In this dissertation, a host of fundamental enzyme engineering and characterization techniques are applied to study and address the thermodynamic, transport, and kinetic challenges arising from the use of enzyme cascades for multistep catalysis. In Chapter 2, a modular approach for the design of cofactor-independent transhydrogenases was explored and developed to enable catalysis and cofactor recycling in a single protein. Individual, unmodified active sites were modularly assembled and their activity catalytically coupled using biomimetic PEG-NAD(H) swing arms. Protein engineering and molecular design were used to increase the swing arm content and increase the activity of the transhydrogenases without detriment to their selectivity, circumventing the typical tradeoffs associated with modifications to the active site. The modularity of this approach was illustrated through the creation and characterization of four novel transhydrogenase enzymes with behavior that was predictable from that of the parent enzyme active sites. In Chapter 3, the kinetic behavior of the formolase (FLS) enzyme was comprehensively characterized to facilitate its use in carbon fixation cascades. A mechanistic rate equation and theory-based figures of merit were derived from first principles and used to capture and rank the full catalytic performance of 8 FLS variants under different conditions. The transition state specificity constant derived in this chapter was used to quantify product preference. In Chapter 4, the limiting performance of the formaldehyde dehydrogenase enzyme was explored within the context of a NADH-dependent pathway for the reduction of CO₂ to methanol. Protein engineering experiments targeting the elongated cofactor binding loop of the enzyme were investigated as a means of enhancing NADH-dependent formate reductase activity, but all mutations in the loop region dramatically reduced protein expression levels. Pathway flux was increased through the substitution of the formaldehyde dehydrogenase with a better performing homolog. In Chapter 5, a model carboligation pathway for the conversion of formaldehyde to glycerol and ethylene glycol was built using the FLS, glycerol dehydrogenase, and phosphite dehydrogenase enzymes. The impact of the low activity and substrate affinity of the FLS enzyme on pathway carbon and energy efficiencies was examined in purified proteins and crude lysates. High energy efficiencies, as quantified through the efficiency of NADH utilization, were achieved only with purified proteins. Cofactor regeneration was also shown to lower the cofactor requirement from stoichiometric to catalytic concentrations. In this work, we utilized a range of characterization techniques to study the limitations and challenges involved in the use of both NADH-dependent oxidoreductases and designed enzymes for multistep catalysis, and used protein engineering to address them. The insights gained from this work will facilitate the efficient use of these enzymes for linear carbon fixation as well as other biocatalysis applications.

A comparative study of the electro-oxidation of ethanol and methanol was carried out on a Pt/ceria composite electrode prepared by electro-deposition. Modification of the Pt electrode was realized by co-deposition from a 1.0 mM K₂PtCl₆ solution that also contained a 20 mM suspension of ceria. The electro-catalytic activities and stabilities of the Pt/ceria catalyst towards ethanol electro-oxidation reactions (EOR) and methanol electro-oxidation reactions (MOR) were investigated by potentiodynamic and potentiostatic methods in 0.5 M sulfuric acid and 1.0 M sodium hydroxide solutions at various concentrations of ethanol and methanol. The kinetics of ethanol and methanol on a Pt/ceria composite electrode were measured in 0.5 M sulfuric acid and 1.0 M sodium hydroxide solutions using a rotating disk electrode (RDE). Cyclic voltammetry was employed in temperatures ranging from 15 to 55°C to provide quantitative and qualitative information on the kinetics of alcohol oxidation. The temperature dependence of the electro-catalytic activities afforded the determination of apparent activation energies for ethanol and methanol oxidation.

京都大学 / 新制・課程博士 / 博士(エネルギー科学) / 甲第24922号 / エネ博第464号 / 新制||エネ||87(附属図書館) / 京都大学大学院エネルギー科学研究科エネルギー社会・環境科学専攻 / (主査)教授 河本 晴雄, 教授 亀田 貴之, 准教授 南 英治 / 学位規則第4条第1項該当 / Doctor of Energy Science / Kyoto University / DFAM