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Phospholamban (PLN) is an integral membrane protein that regulates the sarco(endo)plasmic Ca2+-ATPase (SERCA2a) within the cardiac sarcoplasmic reticulum (CSR). SERCA2a regulates intracellular Ca2+- handling and thus plays a critical role in initiating cardiac contraction and relaxation. It is believed that dysregulation of SERCA2a is a contributing factor in human heart failure patients. Even though there have been substantial advancements in understanding heart failure pharmacological therapies, patient prognosis remains poor. Nitroxyl (HNO), a new candidate heart failure drug therapy, has been shown to enhance overall cardiovascular function in both healthy and failing hearts, at least in part, by increasing Ca²⁺ re-uptake into the CSR. Previous research has shown that activation of SERCA2a by HNO is PLN-dependent; however, the mechanism of action of HNO remains unknown. We propose that HNO, a thiol oxidant, modifies one or more of the three PLN cysteine residues (C36, C41, C46) affecting the regulatory potency of PLN toward SERCA2a. To test this hypothesis, a series of PLN mutants were constructed containing single, double and triple cysteine substitutions. Using the baculovirus expression insect cell system, each PLN cysteine mutant was expressed alone and co-expressed with SERCA2a in insect cells and isolated in cellular endoplasmic reticulum (ER) microsomes. Samples were treated with Angeli's salt (an HNO donor) to determine the role of each PLN cysteine residue in the mechanism of SERCA2a activation by nitroxyl. Using a standard phosphate activity assay and SDS-PAGE/immunoblot techniques, we determined that the PLN cysteine residues at positions 41 and 46 are important in HNO activation of SERCA2a. Both SERCA2a + 41C PLN and SERCA2a + 46C PLN microsomal samples showed a ΔK0.5 of ~0.33 μM and evidence of reversible HNO induced disulfide bond formation. These studies provide important new insight into the mechanism of action of HNO on cardiac SR and thereby help evaluate the drug as a candidate therapy for congestive heart failure. / Ph. D.

In order that further steps could be taken in the attempt to defeat corrosion, it was desirable to find a method for electrodepositing aluminum on other metal surfaces. To meet this need, an investigation was conducted to attempt to find an electrolyte that would be suitable from the field of molten inorganic aluminum and alkali salts. The principal work by other investigators on the electrodeposition of aluminum has been with aqueous solutions which have been proved unusable and with fused alkali-aluminum halide mixtures that have produced crystalline, poorly adherent aluminum coatings. In the present investigations, seven inorganic, fused salt systems were studied. These systems were chloride, fluoride, cyanide, sulfide, thiocyanate, formate and fluoborate. No electrolyte was found that gave a compact, adherent aluminum deposit. Investigation of a fused electrolyte containing 66 mol per cent aluminum chloride, 20 mol per cent sodium chloride and 14 mol per cent potassium chloride at 160 °C produced poorly adherent, dendritic aluminum deposits on a copper cathode at a current density of 0.833 ampere per square decimeter. This coating formed a surface alloy between aluminum and copper when electroplated pieces of copper were heat treated in an electric furnace at 550 °C for 45 minutes and at 1000 °C for one minute. The piece treated at 1000 °C seemed to have deeper penetration of the aluminum. Ratios of 45 to 55, 42 to 58 and 40 to 60 mol per cent aluminum fluoride to potassium fluoride failed to produce a composition that would have a low viscosity at a temperature below the melting point of aluminum, 660 °C. A fused bath of 70 weight per cent potassium sulfide, K₂S₈, and 30 weight per cent aluminum sulfide, Al₂S₇, did not yield aluminum after electrolysis at current densities of 2.5 and 5.0 amperes per square decimeter for three hours at a temperature of 300 °C and using platinum electrodes. A plot of cell potential versus current for the sulfide system indicated oxidation and reduction of the electrolyte with ultimate passivity of the anode. Systems of cyanide, fluoborate and formate proved to be impractical because of the difficulty in handling or obtaining the chemicals involved. Aluminum thiocyanate showed promise as an electrolyte but limitation of time prevented experimental work on this system. / Master of Science

No / We report the structure of the electrical double layer, determined from molecular dynamics simulations, for a range of saline solutions (NaCl, KCl, MgCl2 and CaCl2) at both 0.16 and 0.60 mol kg(-1) on different facets of the gold and silver aqueous interfaces. We consider the Au/Ag(111), native Au/Ag(100) and reconstructed Au(100)(5×1) facets. For a given combination of metallic surface and facet, some variations in density profile are apparent across the different cations in solution, with the corresponding chloride counterion profiles remaining broadly invariant. All density profiles at the higher concentration are predicted to be very similar to their low-concentration counterparts. We find that each electrolyte responds differently to the different metallic surface and facets, particularly those of the divalent metal ions. Our findings reveal marked differences in density profiles between facets for a given metallic interface for both Mg(2+) and Ca(2+), with Na(+) and K(+) showing much less distinction. Mg(2+) was the only ion for which we find evidence of materials-dependent differences in interfacial solution structuring between the Ag and Au. / Veski, Air Force Office for Scientific Research grant #FA9550-12-1-0226

No / This study is primarily focused on proving the potential of miniaturized Raman systems to detect any biomolecular and mineral signal in natural geobiological samples that are relevant for future application of the technique within astrobiologically aimed missions on Mars. A series of evaporites of varying composition and origin from two extremely dry deserts were studied, namely Atacama and Mojave. The samples represent both dry evaporitic deposits and recent evaporitic efflorescences from hypersaline brines. The samples comprise halite and different types of sulfates and carbonates. The samples were analysed in two different ways: (i) directly as untreated rocks and (ii) as homogenized powders. Two excitation wavelengths of miniaturized Raman spectrometers were compared: 532 and 785 nm. The potential to detect carotenoids as biomarkers on Mars compared with the potential detection of carbonaceous matter using miniaturized instrumentation is discussed.

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Thesis advisor: Noah Snyder / Salt marshes are an essential ecosystem for connecting nutrients between coastal and land environments, protecting shorelines from erosion, and providing habitat for various species. Anthropogenic climate change causing sea level rise poses threats to salt marshes and the coastal communities nearby. In southern New Jersey, the relative rate of sea level rise (4.21 ± 0.15 mm/yr from 1911-2022; SLR; NOAA, 2023) is greater than the global average (3.4 ± 0.04 mm/yr). In this study, I measure chronologies, bulk density and organic content (loss on ignition, LOI) from cores collected in 2021-22 at four locations in the Seven Mile Island Innovation Lab (SMIIL) in Stone Harbor, New Jersey to determine multidecadal accretion rates. Chronologies are developed from a radionuclide dating analysis (using concentrations of 210Pb, 241Am, 137Cs and 7Be) following procedures similar to Boyd et al. (2017) and Landis et al. (2016). The accretion rates from 1911-2022 of the four cores analyzed are 4.3 ± 0.2 mm/year, 4.1 ± 0.1 mm/year, 5.2 ± 0.1 mm/yr, and 6.0 ± 0.2 mm/yr, respectively, which are similar to the local SLR rate and are within error of RSLR in Atlantic City. The mean LOI for the 4 four cores is 27.2 ± 19.0%, 21.3 ± 8.9%, 20.2 ± 7.5% and 14.2 ± 13.0%. The mean dry bulk density for the 4 cores is 437 ± 127 kg/m3, 380 ± 103 kg/m3, 415 ± 88 kg/m3, 657 ± 353 kg/m3. The higher accretion rates of the salt marshes in SMIIL compared to relative sea level rise and consistency with the Sadler Effect indicates that the salt marsh vertical accretion rate is keeping up with increases in sea level rise. Thus, the salt marshes are not in immediate risk for inundation from sea level rise and supports the adaptability and resiliency of the salt marsh ecosystem. / Thesis (BS) — Boston College, 2024. / Submitted to: Boston College. Morrissey School of Arts and Sciences. / Discipline: Earth and Environmental Sciences. / Discipline: Departmental Honors.

Background: Dietary salt intake in the South African population exceeds the physiological need. Excessive salt intake is associated with elevated blood pressure levels which may lead to hypertension and cardiovascular accidents. A lifestyle modification such as dietary salt restriction is an inexpensive, effective disease prevention option. Objective: The overall main objectives of this investigation was to: 1) compare salt intake, estimated from a short salt frequency intake questionnaire, with the 24-hour urinary salt excretion and blood pressure of young normotensive healthy white and black South Africans; and 2) compare 24-hour salt excretion and 24-hour blood pressure profiles of normotensive white and black individuals in terms of their knowledge, attitude and behaviour towards dietary salt intake. Study design: The study design was cross-sectional and nested in the baseline phase of the African Prospective Study on the Early Detection and Identification of Cardiovascular Disease and Hypertension in South Africa (African-PREDICT) study. Methods: Multiple methods of data collection were used including anthropometry, biochemical analyses, dietary intakes and cardiovascular measurements. Participants in the study completed the short salt frequency intake questionnaire, describing and quantifying habitual salt intake, and a questionnaire describing knowledge, attitude and behaviour regarding salt intake. Responses to the questionnaires were compared with actual salt intakes estimated from a single 24-hour urine sample and with the 24-hour blood pressure measurements. Results: There was no significant correlation between salt intake based on the questionnaire and 24-h urinary excretion in the white (r=0.07; p=0.40) and black (r=-0.53; p=0.56) participants before and after adjustment for covariates. Estimated salt intake from the questionnaire significantly correlated with systolic blood pressure in white participants (r=0.22, p=0.005) before adjustment for covariates and was no longer significant after adjustment. None of the correlations (unadjusted or adjusted) were significant for the black participants (all p>0.05). The Bland-Altman plots for salt intake showed that the mean difference between the methods used to determine salt intake for the white group is 0.5 g/day, and for the black group is -1.9 g/day. The urinary salt excretion may estimate salt intake to be 9.6 g/day above or 11.1 g/day below the questionnaire’s estimation in the white, and 10.8 g/day above and 18.4 g/day below in the black groups. The level of agreement (Cohen’s Kappa analyses) between the salt frequency questionnaire and the 24-hour urinary salt excretion were determined by categorising the participants in groups who meet the target of <5 grams salt per day or do not. The value of Kappa for the white participants was 0.17 (slight agreement) and for the black participant it was -0.06 (no agreement). In the white participants were a significant increase in both SBP and DBP with increasing tertiles of salt intake according to the questionnaire (p<0.006 and p<0.02 respectively). In the black participants there were no significant difference in BP levels (all p>0.05). The five foods/food groups that contributed most to dietary salt intake in both ethnic groups were discretionary salt, bread, gravy made with stock or gravy powder, soup and biltong. There were no differences in the BP levels between those who answered questions about their knowledge and attitude towards salt intake in both ethnic groups (all p>0.05). Also, there were no differences in their urinary salt excretion (all p>0.05). Only certain behaviours mentioned in the questionnaire were reflected in the salt intake levels and blood pressure. Conclusions: The short salt frequency intake questionnaire can be used to identify food items that contribute to total salt intake. However, the questionnaire considerably underestimates the dietary salt intake. The application of this questionnaire may be helpful in epidemiological studies that evaluate foods which contribute to the total salt intake in order to monitor the average salt intake of a population and to assess the proportion of the population that does not meet the target of less than 5 grams of salt intake per day. It cannot, however, be used to assess the salt intake of an individual. The knowledge, attitude and behaviour of women and men of both ethnic groups are poorly reflected in their actual salt intake and blood pressure, especially among the black participants. The majority of the participants in both ethnic groups consume dietary salt in much higher quantities than the recommended less than 5 grams per day. The current public awareness campaign to decrease salt intake to the target level of less than 5 grams per day by the South African National Department of Health and the Heart and Stroke Foundation is commendable. / MSc (Nutrition), North-West University, Potchefstroom Campus, 2015

Background: Dietary salt intake in the South African population exceeds the physiological need. Excessive salt intake is associated with elevated blood pressure levels which may lead to hypertension and cardiovascular accidents. A lifestyle modification such as dietary salt restriction is an inexpensive, effective disease prevention option. Objective: The overall main objectives of this investigation was to: 1) compare salt intake, estimated from a short salt frequency intake questionnaire, with the 24-hour urinary salt excretion and blood pressure of young normotensive healthy white and black South Africans; and 2) compare 24-hour salt excretion and 24-hour blood pressure profiles of normotensive white and black individuals in terms of their knowledge, attitude and behaviour towards dietary salt intake. Study design: The study design was cross-sectional and nested in the baseline phase of the African Prospective Study on the Early Detection and Identification of Cardiovascular Disease and Hypertension in South Africa (African-PREDICT) study. Methods: Multiple methods of data collection were used including anthropometry, biochemical analyses, dietary intakes and cardiovascular measurements. Participants in the study completed the short salt frequency intake questionnaire, describing and quantifying habitual salt intake, and a questionnaire describing knowledge, attitude and behaviour regarding salt intake. Responses to the questionnaires were compared with actual salt intakes estimated from a single 24-hour urine sample and with the 24-hour blood pressure measurements. Results: There was no significant correlation between salt intake based on the questionnaire and 24-h urinary excretion in the white (r=0.07; p=0.40) and black (r=-0.53; p=0.56) participants before and after adjustment for covariates. Estimated salt intake from the questionnaire significantly correlated with systolic blood pressure in white participants (r=0.22, p=0.005) before adjustment for covariates and was no longer significant after adjustment. None of the correlations (unadjusted or adjusted) were significant for the black participants (all p>0.05). The Bland-Altman plots for salt intake showed that the mean difference between the methods used to determine salt intake for the white group is 0.5 g/day, and for the black group is -1.9 g/day. The urinary salt excretion may estimate salt intake to be 9.6 g/day above or 11.1 g/day below the questionnaire’s estimation in the white, and 10.8 g/day above and 18.4 g/day below in the black groups. The level of agreement (Cohen’s Kappa analyses) between the salt frequency questionnaire and the 24-hour urinary salt excretion were determined by categorising the participants in groups who meet the target of <5 grams salt per day or do not. The value of Kappa for the white participants was 0.17 (slight agreement) and for the black participant it was -0.06 (no agreement). In the white participants were a significant increase in both SBP and DBP with increasing tertiles of salt intake according to the questionnaire (p<0.006 and p<0.02 respectively). In the black participants there were no significant difference in BP levels (all p>0.05). The five foods/food groups that contributed most to dietary salt intake in both ethnic groups were discretionary salt, bread, gravy made with stock or gravy powder, soup and biltong. There were no differences in the BP levels between those who answered questions about their knowledge and attitude towards salt intake in both ethnic groups (all p>0.05). Also, there were no differences in their urinary salt excretion (all p>0.05). Only certain behaviours mentioned in the questionnaire were reflected in the salt intake levels and blood pressure. Conclusions: The short salt frequency intake questionnaire can be used to identify food items that contribute to total salt intake. However, the questionnaire considerably underestimates the dietary salt intake. The application of this questionnaire may be helpful in epidemiological studies that evaluate foods which contribute to the total salt intake in order to monitor the average salt intake of a population and to assess the proportion of the population that does not meet the target of less than 5 grams of salt intake per day. It cannot, however, be used to assess the salt intake of an individual. The knowledge, attitude and behaviour of women and men of both ethnic groups are poorly reflected in their actual salt intake and blood pressure, especially among the black participants. The majority of the participants in both ethnic groups consume dietary salt in much higher quantities than the recommended less than 5 grams per day. The current public awareness campaign to decrease salt intake to the target level of less than 5 grams per day by the South African National Department of Health and the Heart and Stroke Foundation is commendable. / MSc (Nutrition), North-West University, Potchefstroom Campus, 2015

No description available.