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The tolyporphin A structure contains a tetrapyrrolic bacteriochlorin macrocycle and also consists of two glycosyl groups directly connected to the pyrroles. In this thesis, 3-glycosylated pyrrole was reacted with Eschenmoser's salt to produce N,N-dimethylamino methylated derivative in 95 % yield. Then, the product was reacted with pyrrole under microwave irradiation to produce glycosylated dipyrromethane in 44 % yield. Mono-glycosylated porphyrin was formed by reacting glycosylated dipyrromethane with 1,9-bis (imino)-5-phenyl dipyrromethane under the standard procedure, 1H NMR was used to confirm the new products.

Thesis advisor: Rudolph Hon / Road salt deicers are necessary for road safety, yet pose a risk to wildlife and public water supplies by increasing major ion loads above EPA limits. To better understand the fate of deicers after application, we need to know the migration routes and subsurface pathways that deicers take from their sources to points of discharge. This project used sediment core analysis and major ion chemistry analysis of water quality to evaluate the pathways of NaCl and CaCl2 through the subsurface of a shallow glacial aquifer in south east New England. Assessment of sediment cores revealed a heterogeneous subsurface with great variation in hydraulic conductivity. Analysis of major ion concentrations and ion ratios showed both short, direct pathways and deeper, longer pathways indicative of yearly salt retention in the aquifer. Ion chemistry also revealed deicer sources by their variable NaCl to CaCl2 ratios. / Thesis (MS) — Boston College, 2015. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Earth and Environmental Sciences.

Fuel cells are one of the most promising clean energy technologies under development. But a constraining factor in their further development is related to operating temperature ranges of current fuel cell systems, which is either low or high temperature. The intermediate temperature (200¡ÃƒÂ£C to 600¡ÃƒÂ£ C) would be the most desirable temperature range for a fuel cell for most applications, but there is no existing mature fuel cell technology in this range, mainly because of an absence of appropriate electrolytes. An effort to develop an intermediate-temperature molten-salt electrolyte fuel cell (IT-MSFC) was undertaken in this study. As a start, molten KOH was used as an electrolyte around 200¡ÃƒÂ£ C supported on a porous matrix. Tests used Pt loaded carbon cloth to be the electrode-catalyst layer, hydrogen and oxygen as fuel. The major challenge for this fuel cell was to hold electrolyte within a suitable porous support layer, without crossover of fuel gas during operation. Performance was short-lived, thus several ceramic materials were investigated in this research, including Zirconia felt, Zirconia disk, and porous NiO. To evaluate the properties of KOH molten salts working for IT-MSFCs, the performances were compared to fuel cell tests with KOH saturated solution and phosphoric acid with the same electrolyte support. KOH molten salt has large potential to work as electrolyte, with an open circuit voltage (OCV) of 1.0 V, and had linear performance curve between 1.0 V and 0.6 V, which is characteristic of fuel cells with low kinetic overpotentials. The highest performance was got by using porous NiO support in certain porosity range. Longevity of the fuel cell was a little better than the former, but still far from practical application. The result suggested that the capillarity, permeability and compatibility of support material are essential for performance of this type of fuel cell. Besides the problem of electrolyte II retention by the support matrix, unsuitable water management, degradation of the gas diffusion layer and catalyst may also reduce the fuel cell performance. Although this work is at a preliminary stage, it has demonstrated the immense potential of IT-MSFC, and a great deal of additional work will be required to produce a practical fuel cell.

Salt-sensitive hypertension, a key component of essential hypertension, affects approximately 50% of hypertensive patients and dramatically increases the risk of adverse cardiovascular events. Excess dietary sodium intake is an established cause of hypertension, but there remains no clear understanding of the central molecular pathways acting to facilitate sodium homeostasis and normotension in salt-resistant phenotypes, or potential derangements in these antihypertensive systems in salt-sensitive hypertension. Therefore, there exists a critical need to elucidate the neural mechanisms that account for the phenotypic difference between salt-resistance and salt-sensitivity. The current studies hypothesize that hypothalamic paraventricular nucleus (PVN) Gαi2 proteins mediate the central responses activated to counter the development of salt-sensitive hypertension. Salt-resistant (Sprague-Dawley, Dahl salt-resistant, Brown Norway) and salt-sensitive (Dahl salt-sensitive, 8-congenic Dahl salt-sensitive) rat phenotypes were utilized to investigate the role of central Gαi2 proteins in the physiological regulation of blood pressure in response to acute and chronic challenges to sodium homeostasis. Salt-resistant animals remain normotensive following chronic high salt intake and exhibit an endogenous site-specific increase in PVN Gαi2 proteins. Exogenous oligodeoxynucleotide-mediated downregulation of Gαi2 proteins throughout the brain evokes rapid renal nerve-dependent hypertension, sodium retention, and sympathoexcitation in animals typically salt-resistant. In salt-sensitive animals, Gαi2 protein downregulation exacerbated salt-sensitive hypertension via a renal nerve-dependent mechanism. Central Gαi2 protein downregulation also resulted in prolonged elevated blood pressure mediated by an attenuated activation of parvocellular PVN neurons. The PVN is the critical brain site at which the antihypertensive compensatory action of Gαi2 protein mediated signal transduction influences blood pressure regulation. PVN Gαi2 protein-mediated signal transduction represents a conserved central molecular pathway mediating sympathoinhibitory renal nerve-dependent responses evoked to maintain sodium homeostasis and a salt-resistant phenotype. This also differentially influences PVN parvocellular neuronal activation, sympathetic outflow, and arterial pressure in response to sodium challenges, independently of actions on magnocellular neurons and vasopressin release. Impairment of this signaling mechanism contributes to the development of salt-sensitive hypertension. Collectively, this work highlights the complex interaction between the CNS and kidney, and the role of the sympathetic nervous system, in the short and long-term regulation of blood pressure.

Salt stress, or salinity, is one of the most common environmental stresses affecting crop yield worldwide. Due to the prevalence of salinity stress, it is not surprising that plants have evolved mechanisms to tolerate osmotic and ionic stress caused by salinity. Dehydrins are intrinsically unstructured proteins that accumulate in photosynthetic organisms under dehydrating conditions, such as salinity, and are thought to confer stress tolerance through the stabilization of cellular membranes. <i>Thellungiella salsuginea</i>, a close relative of <i>Arabidopsis thaliana</i>, is a halophyte that thrives in the Canadian sub-Arctic (Yukon Territory), that is able to tolerate extreme conditions, including high salinity. TsDHN-2 is a basic dehydrin from <i>Thellungiella</i> whose transcript increases over 10-fold in response to salinity treatment. Using RNA interference (RNAi) methodology, TsDHN-2 has been silenced and these lines were used in this study to investigate the role TsDHN-2 may play in the salt tolerance of <i>Thellungiella</i>. RNAi line 7-8 presented a 41% reduced expression of TsDHN-2 in comparison to wild-type (WT). Seed of this line showed a 15% germination rate compared to 40% in WT in the presence of 100 mM NaCl. Salinity stress experiments were performed by treating the RNAi lines and WT plants with 300 mM NaCl for up to two weeks. Line 7-8 exhibited a 6.2% greater decrease in photochemical efficiency of photosystem II (PSII) as estimated by the variable to maximal fluorescence ratio (F_v/F_m) and showed 5% greater phenotypic damage than WT when estimated visually. Concentrations of the compatible osmolyte proline increased in response to salt treatment by 3.4-fold in WT and 8.1-fold in line 7-8, suggesting this compound may be a marker for salinity tolerance. Collectively, these data support the notion that TsDHN-2 plays a role in the salinity tolerance mechanisms of <i>Thellungiella</i>.

Salt stress, or salinity, is one of the most common environmental stresses affecting crop yield worldwide. Due to the prevalence of salinity stress, it is not surprising that plants have evolved mechanisms to tolerate osmotic and ionic stress caused by salinity. Dehydrins are intrinsically unstructured proteins that accumulate in photosynthetic organisms under dehydrating conditions, such as salinity, and are thought to confer stress tolerance through the stabilization of cellular membranes. <i>Thellungiella salsuginea</i>, a close relative of <i>Arabidopsis thaliana</i>, is a halophyte that thrives in the Canadian sub-Arctic (Yukon Territory), that is able to tolerate extreme conditions, including high salinity. TsDHN-2 is a basic dehydrin from <i>Thellungiella</i> whose transcript increases over 10-fold in response to salinity treatment. Using RNA interference (RNAi) methodology, TsDHN-2 has been silenced and these lines were used in this study to investigate the role TsDHN-2 may play in the salt tolerance of <i>Thellungiella</i>. RNAi line 7-8 presented a 41% reduced expression of TsDHN-2 in comparison to wild-type (WT). Seed of this line showed a 15% germination rate compared to 40% in WT in the presence of 100 mM NaCl. Salinity stress experiments were performed by treating the RNAi lines and WT plants with 300 mM NaCl for up to two weeks. Line 7-8 exhibited a 6.2% greater decrease in photochemical efficiency of photosystem II (PSII) as estimated by the variable to maximal fluorescence ratio (F_v/F_m) and showed 5% greater phenotypic damage than WT when estimated visually. Concentrations of the compatible osmolyte proline increased in response to salt treatment by 3.4-fold in WT and 8.1-fold in line 7-8, suggesting this compound may be a marker for salinity tolerance. Collectively, these data support the notion that TsDHN-2 plays a role in the salinity tolerance mechanisms of <i>Thellungiella</i>.