Ammonia

Three sources of halitosis exist, potentially in any combination: mouth, nasal cavity or alveolar breath. There has been no universally accepted protocol which differentiates and quantifies each odour source separately. In this study a new gas measurement protocol is described and tested to determine whether each odour source can be separately detected without contamination. Ninety healthy volunteers were divided into three groups. Hydrogen sulphide (H2S), volatile organic compounds (VOCs) and hydrogen (H2) were artificially generated in the mouth, nose and pulmonary alveoli, respectively. VOC, ammonia (NH3), sulphur dioxide (SO2), H2S and H2 gas readings from mouth, nose and alveolar air were measured and compared. Measurements were taken before and during gas generation. Contamination of nasal air (2.8%) and alveolar air (5.0%) by oral H2S; alveolar air (2.06%) and oral air (4%) by nasal organic gas; nasal air (18.43%) and oral air (9.42%) by alveolar H2 was calculated. The result...

The objective of this study was to evaluate the effects of a diet supplemented with branched-chain amino acids (BCAA; 3.57% and 4.76%) on the performance and glycogen metabolism of trained rats. Thirty-six adult male Wistar rats received the control diet (AIN-93M) (n = 12) and two diets supplemented with BCAA (S1: AIN-93M + 3.57% BCAA, n = 12, and S2: AIN-93M + 4.76% BCAA, n = 12) for 6 weeks. The training protocol consisted of bouts of swimming exercise (60 min day −1 ) for 6 weeks at intensities close to the lactate threshold. On the last day of the experiment, all groups were trained for 1 h (1H) or were submitted to the exhaustion test (EX). The time to exhaustion did not differ between groups. The groups submitted to the exhaustion test presented a reduction in plasma glucose and an increase in plasma ammonia and blood lactate concentrations compared to the 1H condition. In the 1H condition, hepatic glycogen concentration was significantly higher in group S2 compared to the control diet and S1 groups (132% and 44%, respectively). Group S2 in the 1H condition presented a higher muscle glycogen concentration (45%) compared to the control diet group. In the EX condition, a significantly higher hepatic glycogen concentration was observed for group S2 compared to the control diet and S1 groups (262% and 222%, respectively). Chronic supplementation with BCAA promoted a higher hepatic and muscle glycogen concentration in trained animals, with this effect being dose dependent.

The aim of the study was to test the hypothesis that creatine supplementation with concomitant carbohydrate ingestion during recovery period after rapid body mass reduction accelerates the restoration of body mass and physical performance in well-trained wrestlers. A double-blind, placebo-controlled cross-over study was conducted on five young healthy male wrestlers, who reduced their body mass by 4.5-5.3% in two series of investigations separated by one month. During 17 hrs recovery period they consumed controlled diet supplemented in random order with glucose (GL trial) or with glucose plus creatine (GL+CR trial). The capacity of the subjects to perform submaximal and maximal (W(max)) intensity work was measured using 5 min intermittent intensity test exercise at the Cybex II device before (Test 1) and after body mass loss (Test 2), also after the recovery (Test 3) on both trials. There was no effect of treatment on the extent of body mass regain during 17 hrs recovery. A signific...

Comparative 16S rRNA sequencing was used to evaluate phylogenetic relationships among selected strains of ammonia- and nitrite-oxidizing bacteria. All characterized strains were shown to be affiliated with the proteobacteria. The study extended recent 16S rRNA-based studies of phylogenetic diversity among nitrifiers by the comparison of eight strains of the genus Nitrobacter and representatives of the genera Nitrospira and Nitrospina. The later genera were shown to be affiliated with the delta subdivision of the proteobacteria but did not share a specific relationship to each other or to other members of the delta subdivision. All characterized Nitrobacter strains constituted a closely related assemblage within the alpha subdivision of the proteobacteria. As previously observed, all ammonia-oxidizing genera except Nitrosococcus oceanus constitute a monophyletic assemblage within the beta subdivision of the proteobacteria. Errors in the 16S rRNA sequences for two strains previously d...

The black liquor is a byproduct of the kraft pulping process that contains more than half of the exergy content in the total woody biomass fed to the digester, representing a key supply of renewable energy to the pulping process. In this work, the conventional scenario of the black liquor use (i.e., concentration and combustion) is compared with the black liquor upgrading (via) gasification process for ammonia production in terms of economics, exergy efficiency and environmental impact. The combined energy integration and exergy analysis is used to identify the potential improvements that may remain hidden to the energy analysis alone, namely, the determination and mitigation of the process irreversibility. As a result, the exergy efficiencies of the conventional and the integrated cases average 40% and 42%, respectively, whereas the overall emission balance varies from 1.97 to −0.69 tCO2/tPulp, respectively. The negative CO2 emissions indicate the environmental benefits of the proposed integrated process compared to the conventional kraft pulp mill.

The main objective of this article is to analyze the feasibility of producing ammonia as main component for the synthesis of nitrogen fertilizers in the state of Cear a e Brazil. The potential for the ammonia production, via the HabereBosch process with electrolytic wind and solar photovoltaic hydrogen, is described with maps showing it per unit area in each municipal division of the state. Thus, by using high resolution solar radiation digital databases and average wind regimes databases (speed, Weibull factor, terrain roughness) available for Cear a, news maps of the potentials for solar and wind hydrogen are developed. Then a map of renewable hydrogen as the sum of both was created along with the corresponding potential for ammonia production with this renewable hydrogen. Land use and environmental externalities were considered as areas where energy development would be restricted.

The present study investigated the chemical composition of precipitation at Comba, Madgaon, South Goa during southwest monsoon. The rainwater samples were collected on event basis during June-September 2008 and were analyzed for pH, major anions F, Cl, NO 3 , SO 4 ) and cations (Ca, Mg, Na, K, NH 4 ). The pH value varied from 5.36 to 6.91 (6.25 ± 0.28) indicating alkaline nature of rainwater and dominance of Cl and Na in precipitation. The Neutralization factors (NF) was found to be NFCa = 1.22, NFMg = 0.42, NFNH 4 = 0.37 and NFK = 0.14 indicating below cloud process in which crustal components are responsible for neutralization of anions.

Earlier studies demonstrated that oscars, endemic to ion-poor Amazonian waters, are extremely hypoxia tolerant, and exhibit a marked reduction in active unidirectional Na + uptake rate (measured directly) but unchanged net Na + balance during acute exposure to low P O 2 , indicating a comparable reduction in whole body Na + efflux rate. However, branchial O 2 transfer factor does not fall. The present study focused on the nature of the efflux reduction in the face of maintained gill O 2 permeability. Direct measurements of 22 Na appearance in the water from bladder-catheterized fish confirmed a rapid 55% fall in unidirectional Na + efflux rate across the gills upon acute exposure to hypoxia (P O 2 =10-20 torr; 1 torr=133.3 Pa), which was quickly reversed upon return to normoxia. An exchange diffusion mechanism for Na + is not present, so the reduction in efflux was not directly linked to the reduction in Na + influx. A quickly developing bradycardia occurred during hypoxia. Transepithelial potential, which was sensitive to water [Ca 2+ ], became markedly less negative during hypoxia and was restored upon return to normoxia. Ammonia excretion, net K + loss rates, and 3 H 2 O exchange rates (diffusive water efflux rates) across the gills fell by 55-75% during hypoxia, with recovery during normoxia. Osmotic permeability to water also declined, but the fall (30%) was less than that in diffusive water permeability (70%). In total, these observations indicate a reduction in gill transcellular permeability during hypoxia, a conclusion supported by unchanged branchial efflux rates of the paracellular marker [ 3 H]PEG-4000 during hypoxia and normoxic recovery. At the kidney, glomerular filtration rate, urine flow rate, and tubular Na + reabsorption rate fell in parallel by 70% during hypoxia, facilitating additional reductions in costs and in urinary Na + , K + and ammonia excretion rates. Scanning electron microscopy of the gill epithelium revealed no remodelling at a macro-level, but pronounced changes in surface morphology. Under normoxia, mitochondria-rich cells were exposed only through small apical crypts, and these decreased in number by 47% and in individual area by 65% during 3 h hypoxia. We suggest that a rapid closure of transcellular channels, perhaps effected by pavement cell coverage of the crypts, allows conservation of ions and reduction of ionoregulatory costs without compromise of O 2 exchange capacity during acute hypoxia, a response very different from the traditional osmorespiratory compromise.

Background: Sclerema is an uncommon, life-threatening condition, usually of newborns, with a case-fatality rate ranging from 50 to 100%. Very little is known about factors influencing outcome. Aim: To identify clinical and biochemical predictors associated with fatal outcome of sclerema in infants with diarrhoea. Methods: Thirty infants with sclerema admitted to the Special Care Unit of the Dhaka Hospital of ICDDR,B with diarrhoea from May 2005 to end April 2006 were studied prospectively. Nine infants who died (30%) were considered to be cases while the 21 who survived constituted the comparison group. Hypothermia, severe malnutrition, septic shock, serum ammonia and CRP levels were considered to be predictors of death. Differences in proportions were compared by the x 2 test and mean differences were compared using Student's t-test or the Mann-Whitney test, as appropriate. Results: The mean age of the 30 infants was 2.1 months (range 12 d to 8 m). Fatal cases were more likely than survivors to be associated with severe underweight, a positive blood culture and higher serum ammonia and serum CRP levels. After adjusting for possible confounders in logistic regression analysis, the likelihood of death was higher in infants admitted with septic shock or who developed it soon after admission (OR 17.96, 95% CI 1.5-220.4, p50.024). Conclusions: Sclerema is associated with a high fatality rate and scleremic infants with diarrhoea who present with septic shock are at a greater risk of death.

The ammonia (NH3) and nitrate (NO3−) threshold concentrations in rearing water of juvenile pikeperch (Sander lucioperca) were assessed. Pikeperch with an initial mean (SD) weight of 17.7 (4.2) g were exposed to 0.9 (control), 3.6, 5.2, 7.1, 11.2 and 18.9 μM NH3 in the water for 42 days. Plasma NH4+ concentrations stayed at control levels (~650 μM) up to 11.2 μMNH3 in the water. At the highestwater NH3 concentration tested, plasma
NH4+ had more than doubled to 1400 μM. Based on the specific growth rate, the EC10 value for NH3 was 5.7 μM. When pikeperch (initial mean (SD) weight of 27.0 (4.9) g) were exposed to 0.1 (control), 1.5, 2.3, 3.7, 6.1, 10.2, 15.8 and 25.6 mM NO3− for 42 days, mean (SD) plasma NO3− concentrations increased linearly from 88 (47) to 5993 (899) μM at the highest ambient NO3− level. Feed intake, specific growth rate and feed conversion ratio were not affected. Neither NH3 nor NO3− exposure significantly affected haematocrit, plasma concentrations of cortisol, glucose, lactate, osmolality, gill morphology or branchial Na+/K+-ATPase activity in pikeperch. For juvenile pikeperch we advise not to exceed a water NH3 concentration of 3.4 μM(0.05 mg NH3–N/L), the lower limit of the 95% confidence interval of the EC10 value for SGR, to ensure proper physiology and growth. For NO3− we advise not to exceed 25 mM (350 mg NO3– - N/L). This criterion is based on the highest NO3− concentration tested (25.6 mM). As no negative effects were detected at the highest concentration tested, the actual NO3− threshold probably exceeds 25.6 mM.

Growth, morphology, NH 4 þ uptake and mineral allocation in Salvinia cucullata Roxb. ex Bory grown with different amounts of NH 4 þ were investigated. Plants of uniform size were grown on full strength Smart and Barko medium with different NH 4 þ concentrations (0.5, 1, 5, 10 and 15 mM) and incubated in a greenhouse for four weeks. Salvinia cucullata grew well in the medium with 0.5-1 mM NH 4 þ with a relative growth rate of 0.11-0.12 d À 1 without exhibiting NH 4 þ toxicity symptoms. With an NH 4