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The selective catalytic reduction by ammonia (NH3-SCR) of nitrogen oxides (NOx) is a promising technology that is applied to eliminate NOx pollutants from combustion sources like diesel engines. Mn-based oxides are considered a promising catalyst for this process and many efforts were exerted by scholars to make improvements, including addition of other elements to the catalyst framework. The present study investigates the reaction mechanism and pathways using in-situ DRIFTS FTIR analysis for three Mn-based catalysts: a) mixed metal oxide MnCeTiOx, b) Mn impregnated on mesoporous titanium silicate-1 Mn/MesoTS1, and c) Mn/MesoTS1 after protection by secondary growth of silicalite-1 abbreviated as SG-Mn/MesoTS1. Various experiments were carried out on all the catalysts involving pre adsorbing NH3 then introducing NO+O2 to react with the pre adsorbed species and vice versa. It was found that the mixed metal oxide, MnCeTiOx, exhibited higher activity due to variation of different metals and higher metal content compared to the Mn-zeolite catalysts, approximately 29 Wt% Mn vs 4 Wt %, respectively. However, from comparing the two Mn-zeolite catalysts, each containing roughly 5 Wt% Mn, the catalyst after protection by secondary growth, SG-Mn/MesoTS1, showed improvement in the adsorption capability enhancing the overall performance due to the higher amount of acid sites than Mn/MesoTS1, explained by the presence of additional Brønsted and Lewis acid sites. From DRIFTS experiments, both E-R and L-H mechanism could be coexisting and taking place at 150C for all three catalysts. However, it was concluded that although both mechanisms could take place during the reaction, the acid sites on the catalyst surface for all three samples mostly favor the adsorption of NH3 species over NOx species making the E-R mechanism more assertive at 150C.

Intercritically annealed medium manganese steels are a promising third-generation advanced high-strength steel candidate, relying on large fractions of Mn-enriched retained austenite for excellent strength-ductility combinations. The present study proposes a novel cyclic intercritical annealing to promote nucleation and efficient stabilization of austenite in a medium Mn microstructure. Design of the heat treatment is driven by the hypothesis that the distribution of ductile austenite is key in mitigating the strain incompatibility that accelerates failure in these steels. Development and preliminary testing of the heat treatment are first detailed and compared with literature results for equivalent isothermal annealing. The effects of cyclic annealing parameters on the amount and stability of retained austenite are also explored through diffraction methods and mechanical testing. Finally, steps are taken towards quantifying austenite formation during the cyclic treatment, and recommendations are made for adapting the designed heat treatment to thicker gauges.

<p> Intercritically annealed steels, such as dual-phase steels, have found widespread use in automotive structural components due to their high strength and ductility. Elements such as Mn, Al and Si, added to improve the mechanical properties are selectively oxidized during heat treatment and limit the ability of the alloy to be reactively wet during continuous hot-dip galvanizing. Subsequently, a limit has been placed on the amount of alloy which can be used if the steel is to be subsequently galvanized. The specifics of this limit have not been explored in detail, nor has the mechanism of decreased wettability been well demonstrated in the literature other than to say that the galvanizing reaction is limited by oxides on the surface.</p> <p> Using a force balance, it is shown that the presence of MnO on the surface of steels greatly reduces the wettability with a typical galvanizing bath (Zn-0.2wt%Al, Fe-saturated, 460°C). Furthermore, it was determined that this is caused by the additional and rate-limiting step of aluminothermic reduction of the oxide layer with the bath Al, required for subsequent inhibition layer formation. By using a low pO2 during annealing, the wettability was improved by reducing the thickness of the MnO layer when compared to intermediate and industrially common values of pO2. Using a high pO2 also resulted in improved wettability since the internal oxide which was formed did not reduce the wettability since it was not exposed to the bath alloy.</p> <p> Improvements in hardenability were also explored via dilatometry showing that the formation of bainite is delayed with increasing Mn content, as well as a decrease in transformation temperatures from γ during cooling (i.e. Ms and Bs). At ~5wt% Mn, only the the transformation to αM could be observed. This opens the door to higher strength, galvanized steels - as well as possibly galvanized martensitic steels.</p> / Thesis / Master of Applied Science (MASc)

京都大学 / 新制・課程博士 / 博士(工学) / 甲第23156号 / 工博第4800号 / 新制||工||1750(附属図書館) / 京都大学大学院工学研究科材料工学専攻 / (主査)教授 辻 伸泰, 教授 奥田 浩司, 教授 安田 秀幸 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

The effect of Mn(III)-salophen, a superoxide scavenger, against oxidative stress was evaluated in <i>Escherichia coli sodA- sodB-</i>. Oxidative stress was imposed by exposure of the cells to paraquat or hyperoxia. Cells were grown in LB medium overnight, washed and resuspended in the indicated glucose/salts medium supplemented with casamino acids. The effect of Mn(III)-salophen in the oxidative stress model <i>in vivo</i> was measured in terms of the cell growth. Mn(III)-salophen ( 60 nM) completely protected <i>E. coli</i>JI132<i>sodA- sodB-</i>against 1.0 μM paraquat. Equivalent amounts of Mn(III) acetate, a Mn(III)-salophen component, also protected against paraquat toxicity in aerobic <i>E. coli</i> JI132<i>sodA- sodB-</i>. Fe(III)-salophen which has no superoxide scavenging activity, did not protect the cells against paraquat toxicity. The protective effect of Mn(III)-salophen against the paraquat toxicity was proposed to come from the intracellular superoxide scavenging activity of either the complex itself, its component Mn(III), or both, but not by inhibiting the uptake of paraquat. The protective effect of Mn(III)-salophen and Mn(III) in the glucose/salts medium containing casamino acids was also observed in <i>E. coli sodA- sodB-</i> in 100% and 50% oxygen. Hyperoxia increases intracellular levels of superoxide radicals that are intercepted by Mn(III)salophen and Mn(III). / Master of Science

No / Small-scale heterogeneity of biogenic carbonate elemental composition can be a significant source of error in the accurate use of element/Ca ratios as geochemical proxies. In this study ion microprobe (SIMS) profiles showed significant small-scale variability of Mg/Ca, Sr/Ca and Mn/Ca ratios in new shell calcite of the marine bivalves Pecten maximus and Mytilus edulis that was precipitated during a constant-temperature culturing experiment. Elevated Mg/Ca, Sr/Ca and Mn/Ca ratios were found to be associated with the deposition of elaborate shell features, i.e. a shell surface stria in P. maximus and surface shell disturbance marks in both species, the latter a common occurrence in bivalve shells. In both species the observed small-scale elemental heterogeneity most likely was not controlled by variable transport of ions to the extra-pallial fluid, but by factors such as the influence of shell organic content and/or crystal size and orientation, the latter reflecting conditions at the shell crystalsolution interface. In the mid and innermost regions of the P. maximus shell the lack of significant small-scale variation of Mg/Ca ratios, which is consistent with growth at constant temperature, suggest a potential application as a palaeotemperature proxy. Cross-growth band element/Ca ratio profiles in the interior of bivalve shells may provide more promising palaeo-environmental tools than sampling from the outer region of bivalve shells.

Various approaches are currently used to treat and manage psoriasis, and biological treatments are often the latest approaches. All biological treatments have major side effects as they are given systemically via injections. One of the latest biological treatments for psoriasis, one which has shown great efficacy with fewer side effects, is Secukinumab. Secukinumab is an anti-IL17 antibody that works by stopping the action of IL17, a cytokine that is known to have a major role in the pathogenesis of psoriasis. This work is based on the development of a new way to commence drug therapy to reduce the side effects of the treatment. Our work is based on the studies of the genotoxicity of the drug Secukinumab in its bulk and liposome form using comet and micronucleus assays on lymphocytes. The results from both assays have illustrated the safety of the drug and demonstrated the reduction of the DNA damage induced in both healthy individuals and patients with psoriasis. Secukinumab significantly decreases-H2O2 induced damage and efficiently attenuates its adverse effects both in the comet (p<0.0001) and micronucleus assays (p<0.01). The two concentrations of Secukinumab used (2.1 and 2.8μg/ml) efficiently decreased H2O2-induced DNA damage in both groups to nearly the level of the negative control. Overall, Secukinumab reveals protective and anti-genotoxic effects by demonstrating its potential in reducing DNA damage caused by oxidative stress and by not inducing any further damage in the lymphocytes of either healthy individuals or patients. Liposomes are highly versatile which have been proven efficient for therapy and research applications. The discovery of new therapies in the treatment of psoriasis is a considerable challenge and is now a necessity. Our study was the first one to determine the genotoxicity of various concentrations of the drug in the lymphocytes of psoriasis patients compared to healthy individuals. In the MTT assay, the data showed a decrease in % cell survival rates after exposure to different concentrations of Secukinumab. Also, the results demonstrated no statistically significant differences on confounding factors such as ethnicity, smoking, drinking habits, gender and age among psoriasis patient and healthy controls. The regulation of gene expression levels of IL-17, IL-22 and RORC were assessed after treatment with Secukinumab in the bulk and liposome form via RT-PCR analysis. Secukinumab bulk (2.1μg/ml) treatment significantly down-regulated gene expression of IL-17, IL22 and RORC to 0.46-fold, 0.47-fold and 0.5-fold, respectively. However, Secukinumab liposome (2.1μg/ml) only decreased the expression of IL-17 and IL-22 significantly, by 0.46-fold and 0.53-fold, respectively. On the other hand, studying the expression of P53 and P21 using qPCR revealed that Secukinumab bulk and liposome has no effect on the expression of these genes in lymphocytes from healthy individuals and psoriasis patients. Western blotting was used to investigate the effect of Secukinumab in both forms on protein expression levels IL-17, IL-22 and RORC. Analysis of the results showed that Secukinumab bulk and liposome had no significant effect on expression levels of any of these proteins in lymphocytes derived from healthy individuals. However, there was a statistically significant down-regulation observed in the protein expression levels of IL-17, IL-22 and RORC in lymphocytes obtained from the psoriasis patients, confirming the sensitivity of the compromised lymphocytes from patient group to Secukinumab treatment. With Secukinumab (bulk form) administration, a 0.5-fold decrease was observed in IL-17, 0.59-fold decrease in IL-22, and a 0.6-fold decrease in RORC expression. However, liposome form reduced their levels to 0.47–fold, 0.5-fold and 0.47–fold, respectively, when compared to the control group. While it had no significant effect on expression of P53 and P21 proteins in lymphocytes from healthy individuals and psoriasis patients and there was no difference observed in their regulation. In conclusion, the use of Secukinumab liposome as topical drug delivery system may be suitable replacement for improving the drug bioavailability and its side effects. / Libyan Cultural Attaché and Libyan embassy