(n.) The act or process of freeing from nitrogen; also, the condition resulting from the removal of nitrogen.
Example Sentences:
(1) Hb was added to an anaerobic bacterial suspension and denitrification was initiated with either KNO2 or KNO3.
(2) A spectrophotometric method has been developed that uses extracellular hemoglobin (Hb) to trap nitric oxide (NO) released during denitrification as nitrosyl hemoglobin (HbNO).
(3) When [15]nitrite was used as substrate for the N2-forming denitrification, 15N2O, 15NO, and 14N15N were obtained as the products.
(4) Simultaneous processes of nitrification and denitrification were observed in optimal aerated manure similar to activated sludge processes.
(5) In faecal slurries, however, denitrification was a relatively minor route of NO3- dissimilation, since only about 3% of the NO3- was converted to gaseous products, with NO3- being mainly reduced to NO2- and NH4+.
(6) Conversely, energy was conserved when either nitrate, nitrite or nitrous oxide functioned as the oxidants during denitrification-dependent proton translocation experiments.
(7) A highly sensitive denitrification bioassay was developed for detection of NO3- and NO2- in rhizosphere soil samples.
(8) The kinetics of each step of denitrification was examined in resting cell suspensions.
(9) Effects of illumination on denitrification varied with electron donors.
(10) Effects of various inhibitors on denitrification were examined in light-succinate and dark-lactate systems.
(11) The regulation of nitrate respiration at the level of transport by oxygen may represent a major mechanism by which the entire denitrification pathway is regulated in P. aeruginosa.
(12) Mineralization of the labile fraction of the soil organic carbon via microbial denitrification occurred without an observed acclimation period and was rapid compared with PAH degradation.
(13) Denitrification by two of the strains was quantitatively studied using cell suspensions.
(14) Comparison of the cell growth during denitrification indicated that the dissimilatory reduction of nitrate to nitrite is an energetically favorable process in F. oxysporum; however, further reduction of nitrite to N2O might be energy-exhausting and may function as a detoxification mechanism.
(15) The yields varied with sparging rates in agreement with a quantitative model of denitrification (Betlach, M. P., and Tiedje, J.M.
(16) Effects of illumination on the denitrification of nitrite were similar to those involving nitrate.
(17) Our observations provide evidence for a denitrification pathway in vivo of NO2(-)----NO----N2O, and N,N-bond formation catalyzed by NO reductase and not by cytochrome cd1.
(18) One of the reasons for this change is the process of denitrification due to changes in the hydrogeochemical conditions in a layer.
(19) The bulk of the denitrification activity was associated with the accumulation of NO3- in the oxidized surface zone of the sediment, but a secondary denitrification zone was occasionally found in the deeper layers where oxidized patches had been introduced by the burrowing activity of the macrofauna.
(20) Reports of the simultaneous use of oxygen and denitrification by different species of bacteria have become more common over the past few years.
Devitrification
Definition:
(n.) The act or process of devitrifying, or the state of being devitrified. Specifically, the conversion of molten glassy matter into a stony mass by slow cooling, the result being the formation of crystallites, microbites, etc., in the glassy base, which are then called devitrification products.
Example Sentences:
(1) This suggests that the devitrification occurring during the use of these materials in high-temperature environments will not necessarily enhance their adverse biological activities despite the production of one phase of crystalline silica.
(2) Devitrification (ice formation during warming) is one of the primary obstacles to successful organ vitrification (solidification without ice formation).
(3) The fibres were examined in the 'as-manufactured' state and after heating at 1200 and 1400 degrees C. Devitrification of the fibres at 1200 degrees C probably gave mullite crystals on the surface and caused the formation of the high-temperature form of cristobalite and, in zirconia grade fibres, the high-temperature, tetragonal form of zirconia as well.
(4) The highest heating rates we observed using catheters occurred at temperatures ranging from about -70 to -40 degrees C, the temperature zone where devitrification usually appears in unstable solutions during slow warming.
(5) Biological data showed that this devitrification was associated with severe loss of cell function.
(6) This, together with the RGA results, suggests the absence of devitrification or ice crystal growth during the drying procedure.
(7) Of particular note is the anomalous shift in devitrification temperature (Td) to lower temperatures following increased time of annealing at sub-Tg temperatures.
(8) The purpose of the present studies was to define the devitrification process: to determine nucleation rates, ice-crystal growth rates, and the distribution of ice-crystal size and to evaluate the applicability of existing quantitative models of these processes which have successfully approximated the behavior of other aqueous systems.
(9) Very high rates of survival (77-89%) of oocytes exposed to the cryoprotectant media, but without the vitrification, together with extreme variability in results between straws in the vitrified groups, suggest that losses in viability during vitrification may result from ice damage during devitrification of the medium.
(10) Devitrification is a major problem which must be overcome for successful organ cryopreservation.
(11) However, if these cell suspensions were warmed rapidly to -70 degrees C and then held for 5 min, allowing devitrification to occur, the preparation contained significant amounts of both intra- and extracellular ice.
(12) Results obtained indicate that drying is complete below the devitrification temperature of amorphous phase tissue water.
(13) It appears that it should be possible to warm vitrified rabbit kidneys rapidly enough under high-pressure conditions to protect them from devitrification.
(14) As a result of these studies we concluded that: intracellular freezing is lethal, but avoidance of freezing during fast cooling is not sufficient to provide complete protection; a subtle freezing injury in the cryoprotected monocytes can be correlated with a measurable increase in devitrification on warming; and the cell contents form more stable glasses than the Hanks' balanced salt solution with fetal calf serum used as the extracellular medium.
(15) In both cases, high survival requires that subsequent warming be rapid, to prevent recrystallization or devitrification.
(16) A systematic study of the errors of low-temperature recording of kinetics of the cytochrome oxidase-CO reaction had identified the classic devitrification process of Keilin & Hartree [(1950) Nature (London)165, 504-505].
(17) Devitrification can be initiated on fracture planes and on bubbles, but the focus of attention here is on devitrification by ordinary heterogeneous and homogeneous mechanisms, which are the most relevant for organ preservation by vitrification.
(18) An apparatus has been produced that can remove amorphous phase tissue water via molecular distillation without devitrification or rehydration.
(19) Whether corneas can be cooled fast enough in these solutions to achieve vitrification and warmed fast enough to avoid devitrification remains to be determined.
(20) Glass transitions, devitrification, recrystallization and melting behaviour of aqueous solutions of polyvinylpyrrolidone, hydroxyethyl starch and dextran have been established.