Thesis (Ph. D.) -- Lincoln University, 2009. / Also available via the World Wide Web.

Thesis (Ph. D.)--University of Hong Kong, 1996. / Includes bibliographical references (leaves 158-160).

Thesis (M.S. in environmental science)--Washington State University, May 2010. / Title from PDF title page (viewed on July 21, 2010). "School of Earth and Environmental Science." Includes bibliographical references (p. 23-28).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1968. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliography.

Thesis (M.Phys.Ed.)--Memorial University of Newfoundland, 2004. / Includes bibliographical references.

Deaerated acidic, neutral, and basic aqueous N₂0 solutions were irradiated with Co-60 γ -rays in order to: 1) determine the primary yields, and 2) resolve anomalies in relative rate constant ratios of the type k(e⁻aq +S)/k(e⁻aq +N₂0). The yields of the gaseous products N₂, 0₂, and H₂ were determined as a function of both pH and [N₂0]. About 10⁻² M N₂0 is commonly used to evaluate relative rate constant ratios, but this [N₂0] scavenges not only hydrated electrons (e⁻aq ) but also another species, X, (where G(X) = 0.65±0.1), resulting in erroneous rate constant ratios. Yields of primary species found were: Ge⁻aq = 2.4±0.1, G H₂O* ̴ 1.6, and G,H₂⁺, = 0.35±0.05. Kinetic competition studies of the reaction of N₂0 and H⁺ with e⁻aq were undertaken in the concentration ranges 3 x 10⁻⁵ to 2 x 10⁻⁴ M H⁺ and 10⁻⁴ to 10⁻³ M N₂O. The results cannot be explained by: 1) simple competition; 2) charge transfer, or 3) two species being scavenged. They may be explained by assuming a conversion of N₂O to another species in acid solution. This acid species, suggested to be H₂N₂O₂, is apparently five times less reactive toward e⁻aq than is N₂0 in neutral solution. Deaerated neutal N₂0 solutions were irradiated at extremely high intensity with very short pulses of 0.52 Mev electrons. The yields of the gaseous products N₂, O₂, and H₂ were studied in order to examine an expected decrease in solute products, and to determine primary yields at high dose rates. As predicted, significant scavenging occurs for high dose rates only at N₂0 concentrations an order of magnitude larger than those at low dose rates. Also the scavenging, which is complete at ~ 10⁻² M N₂O for low intensity irradiations, is not complete at 2.6 x 10⁻² M N₂0 for high intensity irradiations. These results indicate that the radiation yield of scavengable hydrated electrons is significantly larger at the high intensity used. The yield of hydrogen in pure water (G(H₂) = 1.15±0.2) can be explained on the basis of inter-spur reactions of e⁻aq, H, and OH. / Science, Faculty of / Chemistry, Department of / Graduate

Since the industrial revolution human activities have more than doubled the amount of bioavailable nitrogen (N) on earth leading to far-reaching ecological consequences for coastal marine ecosystems. Salt marsh systems, including their intertidal creek and mudflat sediments, serve as nutrient filters transforming nitrogen and removing it through denitrification. However, as hotspots of nitrogen transformation, these ecosystems are also thought to be sources of nitrous oxide, a powerful greenhouse gas, to the atmosphere. We investigated the influence of various scales of anthropogenic fertilization on the nitrogen cycling in intertidal creek and mudflat sediments in the salt marsh ecosystem of Plum Island Ecosystem Long Term Ecological Research site in northern Massachusetts, USA. Benthic fluxes from whole core incubations showed that long-term fertilization of tidal creek sediment stimulated net denitrification with significantly higher rates in the fertilized creek compared to the reference (162.7 ± 32 and 0.74 ± 39 μmol N m^-2 hr^-1, respectively). However, fertilization also appeared to stimulate dissimilatory nitrate reduction to ammonium (DNRA) with calculated rates also significantly higher in the fertilized compared to reference creek and representing 45 and 11% of total nitrate uptake, respectively. These results indicate that DNRA may outcompete denitrification at higher nitrate concentrations, thus anthropogenic fertilization may be driving tidal creek sediments toward this N regeneration process and thus inhibiting the overall nitrogen removal capacity of the ecosystem. Conversely, a smaller scale, short-term nitrogen addition experiment had no significant impact on nearby tidal flat sediments likely because the fertilization exposure time on the tidal sediments was too short. Overall benthic flux rates were lower in the tidal flat compared to the tidal creeks. However, the tidal flat was also a net N filter with an average net N2 flux of 5.7 ± 2.6 μmol N N m^-2 hr^-1. Rates of nitrification and therefore coupled nitrification-denitrification appeared to be affected by the active microphytobenthos (MPB) community within the tidal flat sediments with oxygen production from photosynthesis fueling coupled denitrification in the light while N fixation dominated under dark conditions. As in the tidal creeks, we found evidence that DNRA is also an important N transformation process within tidal flat sediments. Finally, sediment microprofiling measurements showed these tidal mudflat sediments to be a net sink of N2O (average -6.9 ± 1.7 μmol N2O N m^-2 hr^-1) with significantly higher rates of uptake the longer sediments were exposed to the atmosphere at low tide. Fluxes were shown to be driven by nutrient supply and nitrate limitation of denitrifiers with tidal pulsing. Additionally, smaller, core scale nutrient additions revealed an increase in N2O flux with dissolved inorganic nitrogen (DIN) addition. Importantly, N2O uptake was found to be phosphorus limited. Again, nutrient enrichment appeared to stimulate DNRA over denitrification indicating that fertilization may not only hamper nitrogen removal capacity, but also increase N2O flux to the atmosphere.

Despite the fact that many Nigerian women have limited access to pharmacologic methods for pain management during labor,1,2 previous studies have indicated a demand for such options.3–5 Opioids are a frequently offered analgesic method,5,6 but there are associated risks to the fetus with this type of pain management.7 The use of epidurals, another common method of labor analgesia, has not become prevalent in Nigeria due to lack of awareness, lack of resources, expense, and women’s beliefs that it is not necessary and/or it is harmful.3 Nitrous oxide is an alternative labor analgesic that has reduced side effects compared to opioids and offers pain reduction without the loss of body movement and positioning as is seen with epidurals.7 Because Nigerian women have expressed an interest in increased options for labor analgesics, and nitrous oxide aligns with some of their cultural desires,8 offering nitrous oxide could increase maternal satisfaction.9–12 The literature review examines epidurals, opioids, and nitrous oxide for use as labor analgesics, including their mechanisms of action, benefits, and side effects. It also reviews Nigerian cultural beliefs, the advantages and disadvantages of using nitrous oxide in Nigeria, current practice in Nigeria regarding labor analgesia, Nigerian women’s and healthcare providers opinions on analgesia, additional maternal advantages of labor analgesia outside of pain relief, and birthing locations in Nigeria. The study will be an exploratory, descriptive cross-sectional study that will use a questionnaire to obtain data regarding pregnant women’s knowledge of, and attitudes toward, nitrous oxide as an analgesic during childbirth. It will be administered to 270 pregnant women who visit an antenatal clinic at the Primary Health Care facilities in Mushin Local Government Area located in the state of Lagos, Nigeria. Descriptive statistics of the participants will be reported, and the chi-squared test will be used to determine the associations between the demographics and awareness of various analgesic options, cultural acceptability of using nitrous oxide for labor pain management, and the desirability to use nitrous oxide as a labor analgesic. The use of nitrous oxide for labor analgesia could provide Nigerian women with an important option apart from only opioids or epidurals. It could decrease the use of opioids, thus decreasing their associated health risks during labor.3 Additionally, because vaginal deliveries are an important cultural desire of Nigerian women, nitrous oxide could provide a method for pain management during labor that does not lead to increased risk of cesarean section.13,14

When pediatric patients are admitted to the inpatient or outpatient hospital setting they potentially have to endure procedures that cause pain, fear, and anxiety which can have a lifelong impact on the child's response to future healthcare needs. The purpose of this project was to create a comprehensive program proposal for a nitrous oxide sedation program to minimize those perceptions towards medical procedures. The project utilized a systematic review of literature and secondary data to address the most important indicators for developing a comprehensive program proposal to present to the pediatric leadership team. Multiple studies have shown nitrous oxide having an excellent safety profile in the pediatric population while providing an almost pain and anxiety free procedure. The program proposal will be used to improve pain and anxiety management for pediatric patients requiring procedures such as intravenous access, venipuncture, voiding cystourethrograms, lumbar puncture, bone marrow biopsy, port-a-cath access, PICC line insertion, dressing changes, chest tubes, and wound care. Key stakeholders and content experts were brought together to create the nitrous oxide program proposal which included a new practice guideline, a comprehensive policy and procedure for nitrous oxide administration, and an education plan. The program proposal included other key components necessary for a safe and efficient program such as a pre-assessment to determine if the child is a candidate, monitoring and documentation of nitrous oxide administration, and education for the child/parent(s). The nitrous oxide program for pediatrics was designed as a minimal sedation method to minimize procedural pain, fear, and anxiety in children where medical procedures are a necessary part of treatment.

Indiana University-Purdue University Indianapolis (IUPUI) / Nitrous oxide (N2O) is an atmospheric constituent that contributes to climate warming and stratospheric ozone depletion. A large fraction of the anthropogenic N2O emission originates from agricultural soils suggesting therefore a strong connection between N2O accumulation in the atmosphere and agricultural land management. During the last 2-3 decades, no-till (NT) farming and integration of cover crops into crop rotation represent two major developments in agriculture, but much remains to be learned about the impact of these management approaches on N2O emission and underlying biological soil factors. This dissertation focuses on the contribution of different components of the soil microflora to N2O production, and how different types of cover crops (legume vs grass) affect the soil microbial community composition, mineral N availability, and N2O emission in plowed (PT) and NT soils. To address these questions, several laboratory and greenhouse experiments were conducted. Results of these experiments documented soil microbial community responses to cover crop addition and could inform the selection of cover crops most suitable to soils under different tillage practices.