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1	A study of nitrification in lakes of the English Lake District Hall, G. H. January 1981 (has links) Nitrification became the dominant nitrogen transformation in a number of lakes which accumulated ammonium, in hypolimnetic water, under aerobic conditions. The timing and duration of this activity varied between lakes but was characterized by decreasing ammonium, and increasing nitrate, concentrations. In Grasmere lake this phase was found to be due to the activity of planktonic chemolithotrophic nitrifying bacteria. The observed nitrate concentration increased during this phase and accounted for up to 15% of the total oxygen deficit of the hypolimnion. At similar in situ temperatures nitrification rates and nitrifying bacterial populations were greater in oxidised sediments than in the water column. Littoral sediments were more important than profundal sediments as sites of nitrification due to higher temperatures and the persistance of oxidising conditions to greater depths into these deposits. Within the littoral zone the physical characteristics of the sediment were important with organic rich deposits sustaining greater rates of nitrification than sandy sediments. Nitrate reduction was the primary determining factor of nitrate concentrations in sediment interstitial waters. Some observations on the culture of chemolithotrophic nitrifying bacteria from lakewater were discussed. Reviews of the methodology for nitrification research and nitrification in the lacustrine environment are presented. 577
2	Urea and Non-Protein Nitrogen Metabolism in Infants : With Special Reference to the Sudden Infant Death Syndrome (SIDS) George, Mary January 2001 (has links) <p>A large amount of non-protein nitrogen, in the form of urea and ammonium, is present in human breastmilk; however its physiological role in the infant is as yet not fully understood. It has been hypothesized that an insufficient enteric metabolism of urea could play a role in the sudden infant death syndrome (SIDS). This thesis was undertaken to study the enteric metabolism of non- protein nitrogen in healthy infants, in comparison with those who had succumbed to SIDS.</p><p>Aerobic and anaerobic faecal microflora, were studied in healthy infants from birth to 6 months of age. They were found to appear in faeces within 3 days of birth and were present throughout the first 6 months of life. The effect of nitrate, nitrite and nitric oxide on faecal urease activity was investigated and found to be inhibitory in action. The sigmoid faecal urease activity and sigmoid faecal urea content of SIDS infants were compared to those of control infants; significantly lower sigmoid faecal urease activity and greater sigmoid faecal urea content were found in the SIDS infants. The total number of SIDS cases occurring in Sweden during the period 1990 through 1996 was analysed regarding geographical and seasonal distribution, in relation to the nitrate concentration in drinking water and changes in the groundwater level. The northernmost parts of the country had its highest incidence when the rest of the country had its lowest incidence, and the occurrence of individual deaths was associated with the recharge of groundwater, which is known to increase its nitrate content. The effect of ingested ammonium on carbon dioxide production was determined in healthy infants using the doubly labelled water technique. No change in carbon dioxide production was observed.</p><p>An insufficient enteric metabolism of urea in infants and peak or greatly varying nitrate concentrations in drinking water are associated with the occurrence of SIDS. Ingested ammonium supplements in the given doses did not influence carbon dioxide production in healthy infants.</p> Surgery Urea non-protein nitrogen metabolism SIDS drinking water nitrate concentration carbon dioxide production Kirurgi Surgery Kirurgi
3	Urea and Non-Protein Nitrogen Metabolism in Infants : With Special Reference to the Sudden Infant Death Syndrome (SIDS) George, Mary January 2001 (has links) A large amount of non-protein nitrogen, in the form of urea and ammonium, is present in human breastmilk; however its physiological role in the infant is as yet not fully understood. It has been hypothesized that an insufficient enteric metabolism of urea could play a role in the sudden infant death syndrome (SIDS). This thesis was undertaken to study the enteric metabolism of non- protein nitrogen in healthy infants, in comparison with those who had succumbed to SIDS. Aerobic and anaerobic faecal microflora, were studied in healthy infants from birth to 6 months of age. They were found to appear in faeces within 3 days of birth and were present throughout the first 6 months of life. The effect of nitrate, nitrite and nitric oxide on faecal urease activity was investigated and found to be inhibitory in action. The sigmoid faecal urease activity and sigmoid faecal urea content of SIDS infants were compared to those of control infants; significantly lower sigmoid faecal urease activity and greater sigmoid faecal urea content were found in the SIDS infants. The total number of SIDS cases occurring in Sweden during the period 1990 through 1996 was analysed regarding geographical and seasonal distribution, in relation to the nitrate concentration in drinking water and changes in the groundwater level. The northernmost parts of the country had its highest incidence when the rest of the country had its lowest incidence, and the occurrence of individual deaths was associated with the recharge of groundwater, which is known to increase its nitrate content. The effect of ingested ammonium on carbon dioxide production was determined in healthy infants using the doubly labelled water technique. No change in carbon dioxide production was observed. An insufficient enteric metabolism of urea in infants and peak or greatly varying nitrate concentrations in drinking water are associated with the occurrence of SIDS. Ingested ammonium supplements in the given doses did not influence carbon dioxide production in healthy infants. Surgery Urea non-protein nitrogen metabolism SIDS drinking water nitrate concentration carbon dioxide production Kirurgi Surgery Kirurgi
4	Nitratbericht 2005 / Nitrate report Kurzer, Hans-Joachim 18 September 2006 (has links) (PDF) Im Nitratbericht 2005 werden die Nitratuntersuchungen auf Dauertestflächen sowie die Bewertung verschiedener Einflussgrössen dargestellt. Landwirtschaft Bodenuntersuchung Nitratgehalt agriculture ground survey nitrate concentration ddc:630 rvk:ZA 57118 rvk:ZC 13631 Sachsen Landwirtschaft Umweltbelastung Nitration
5	Comparison of High-Nitrate versus Low-Nitrate Diets on Cardiovascular Health in Post-Menopausal Women January 2017 (has links) abstract: Background. Despite research aimed at understanding the mechanisms of essential hypertension, instances of this condition continue to rise. Recent findings indicate that the administration of dietary nitrates, in the form of beetroot juice and other nitrate-rich vegetables, may offer anti-hypertensive effects in various study populations. Objective. This randomized, placebo-controlled, crossover trial sought to compare the effects of high-nitrate vegetable salads to the effects of low-nitrate canned vegetables on plasma nitrate/nitrite concentration, peripheral and central-aortic systolic and diastolic blood pressures, pulse wave velocity, and flow-mediated dilation. Methods. Healthy, post-menopausal women (n=5; 80% Caucasian; 52.6 ± 5.7 years) with mildly elevated blood pressure (mean blood pressure ≥ 115/70 mm Hg and < 140/80 mm Hg) were randomly assigned to ingest a fresh, high-nitrate vegetable salad or a low-nitrate vegetable medley, twice per day, for a total of 10 consecutive days. Given the crossover design of the trial, participants observed a two to three week washout period followed by reassignment to the opposite condition. Findings were considered significant at a p-value < 0.05, and Wilcoxon Signed-Rank tests compared mean differences between conditions. Results. Plasma nitrate/nitrite concentration was significantly higher following consumption of the high-nitrate versus the low-nitrate condition (p = 0.043). Conversely, the differences in peripheral systolic and diastolic blood pressures were not statistically significant (p = 0.345 and p = 0.684 for systolic and diastolic pressures, respectively) nor were the differences in central-aortic systolic and diastolic blood pressures statistically significant (p = 0.225 and p = 0.465 for systolic and diastolic pressures, respectively). Similarly, when comparing the effects of the high-nitrate condition to the low-nitrate condition, the difference in pulse wave velocity was not statistically significant (p = 0.465). Finally, flow-mediated dilation tended to improve following consumption of the high nitrate condition (p = 0.080). Conclusion. Twice daily consumption of a fresh, high-nitrate vegetable salad significantly increased plasma nitrate/nitrite concentration. Although the trial was underpowered, there was a trend for improved flow-mediated dilation. Finally, twice daily consumption of a fresh, high-nitrate vegetable salad did not significantly lower peripheral or central-aortic systolic or diastolic blood pressures or pulse wave velocity. / Dissertation/Thesis / Masters Thesis Nutrition 2017 Nutrition Aging Blood Pressure Cardiovascular Central-aortic Blood Pressure Flow-mediated Dilation Plasma Nitrate Concentration Post-menopausal Women
6	Nitratbericht 2005 Kurzer, Hans-Joachim 18 September 2006 (has links) Im Nitratbericht 2005 werden die Nitratuntersuchungen auf Dauertestflächen sowie die Bewertung verschiedener Einflussgrössen dargestellt. info:eu-repo/classification/ddc/630 ddc:630
7	Vergleich dielektrisch behinderter Entladungen bezüglich der physikalischen Eigenschaften und der Wirkung auf Holz und Holzwerkstoffe / Comparison of dielectric barrier discharges regarding their physical properties and the influence on wood and wooden materials Peters, Frauke 22 October 2018 (has links) No description available. 570 Plasma Dielektrisch behinderte Entladung reduzierte elektrische Feldstärke Plasmabehandlung von Holz Oberflächenenergie Rotationstemperatur Vibrationstemperatur WPC Hochdichte Faserplatte HDF Ahorn pH Wert Nitratkonzentration Salpetersäure Pufferkapazität Gastemperatur Elektronentemperatur elektronische Temperatur dielectric barrier discharge plasma reduced electrical field strength plasma treatment of wood surface free energy rotational temperature vibrational temperature electron temperature electronical temperature maple wood plastic composite high density fibreboard remote plasma RP coplanar surface barrier discharge CSBD direct dielectric barrier discharge DDBD gas temperature pH nitrate concentration buffer capacity nitric acide Forstwirtschaft (PPN621305413)

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