Search results for "nitrate"

Ceric Ammonium Nitrate - a versatile oxidizing reagent

1994

ChemInform Abstract: Ceric Ammonium Nitrate - A Versatile Oxidizing Reagent

2010

The bleaching efficacy of carbamide peroxide gels containing potassium nitrate desensitizer

2020

Background To evaluate the bleaching efficacy of at-home carbamide peroxide (CP) gels in two concentrations, containing or not a desensitizing agent. Material and methods Forty incisors were divided into four groups (n=10), according to gel concentrations (10% or 22%), and presence or not of 3% potassium nitrate in the gel. A thin layer of gel was applied to the buccal surface of each tooth for 2h/day for 4 weeks. Bleaching efficacy was measured using a spectrophotometer, and ∆E*ab, ∆E00 and ∆WID were calculated. Measurements were performed at baseline, 7, 14, 21, 28, and 35 days following the first gel application. Data were analyzed by two-way RM-ANOVA and Tukey's test (α=0.05). Results R…

Environmental noise aggravates oxidative DNA damage, granulocyte oxidative burst and nitrate resistance in Ogg1−/− mice

2020

Variability in inorganic and organic nitrogen uptake associated with riverine nutrient input in the Gulf of Riga, Baltic Sea

2001

Concentrations and rates of uptake of dissolved organic nitrogen (DON, free amino acids, and urea) and inorganic nitrogen (DIN, nitrate, and ammonium) were measured along two transects in the Gulf of Riga, a sub-basin of the Baltic Sea, during May and July 1996. Concentrations of total dissolved nitrogen (TDN) were 23±3 μg-at N 1−1 in the northern region (mouth) and 41±5 μg-at N 1−1 in the southern region (head) of the Gulf. Rates of nitrogen uptake, determined with15N-labeled substrates, reflected differences in TDN concentration between the regions. In May, uptake of DIN+DON measured 0.17 and 0.43 μg-at N 1−1 h−1 in the northern and southern parts of the Gulf, respectively. In July, DIN+D…

Abundance and activity of nitrate reducers in an arable soil are more affected by temporal variation and soil depth than by elevated atmospheric [CO2]

2011

Elevated atmospheric carbon dioxide concentrations ([CO2]) might change the abundance and the function of soil microorganisms in the depth profile of agricultural soils by plant-mediated reactions. The seasonal pattern of abundance and activity of nitrate-reducing bacteria was studied in a Mini-FACE experiment planted with oilseed rape (Brassica napus). Three depths (0–10, 10–20 and 20–30 cm) were sampled. Analyses of the abundances of total (16S rRNA gene) and nitrate-reducing bacteria (narG, napA) revealed strong influences of sampling date and depth, but no [CO2] effects. Abundance and activity of nitrate reducers were higher in the top soil layer and decreased with depth but were not re…

MANAGING SUBTERRANEAN CLOVER, ANNUAL MEDIC AND VETCH FOR SICILIAN VINEYARD SUSTAINABILITY

2004

During 2005/2006 a vineyards, located in south-west of Sicily (37° 60’ N – 12° 30 E), were subjected to five different soil managements: “conventional” ( T ) soil management using up to eight soil plowing with a five furrow plow; natural cover cropping ( N ), vetch cover cropping ( V ) (Vicia sativa L.); subclover cover cropping ( S ) (trifolium subterraneum var. Clare); medic cover cropping ( M ) (medicago polymorpha var. Santiago). In the layer 0-25 cm, soil moisture, total N, NO3, NH4, and soil organic matter were determined. Fresh and dry biomass weight, and total nitrogen percentage were determined on nine one square meter subplots for each thesis. Soil erosion was measured, using a Ge…

Salinity affects nitrate removal and microbial composition of denitrifying woodchip bioreactors treating recirculating aquaculture system effluents

2019

Abstract This study investigated the effect of salinity on microbial composition and denitrification capacity of woodchip bioreactors treating recirculating aquaculture system (RAS) effluents. Twelve laboratory-scale woodchip bioreactors were run in triplicates at 0, 15, 25, and 35 ppt salinities, and water chemistry was monitored every third day during the first 39 days of operation. Microbial communities of the woodchips bioreactors were analyzed at the start, after one week, and at the end of the trial. Woodchip bioreactors removed nitrate at all salinities tested. The highest NO3-N removal rate of 22.0 ± 6.9 g NO3-N/m3/d was obtained at 0 ppt, while 15.3 ± 4.9, 12.5 ± 5.4 and 11.8 ± 4.0…

Functional stability of the nitrate-reducing community in grassland soils towards high nitrate supply

2006

Abstract To study the effects of short-term fluctuation of nitrate concentrations on the nitrate-reducing community, repacked soil cores were amended with 0, 100 and 300 μ g NO 3 - ‐ N g - 1 soil and incubated for 3, 7 and 14 days, respectively. The nitrate reductase activity was determined in a laboratory-based enzyme assay. In parallel, the community structure of nitrate-reducing microorganisms was characterised by RFLP-PCR using the functional gene narG , which encodes the catalytic site of the membrane-bound nitrate reductase. The community structure remained constant over the experimental period indicating that this functional community is characterised by a high resistance towards flu…

Denitrifying microbial communities along a boreal stream with varying land-use

2019

Streams have an important role in regulating nitrogen (N) transportation from terrestrial ecosystems to downstream waters. Here, we examined how catchment land-use affects potential denitrification rates and the function and composition of denitrifier communities in boreal stream sediments, using stable isotope incubations and qPCR and 454-pyrosequencing targeted on nirS, nirK and nosZ genes. Although land-use influenced the water chemistry as higher nitrite + nitrate (NO x − ) concentration at the agriculture-affected sampling point, sediment organic matter content was found to be the key factor in regulating potential denitrification rates. However, the abundance as well as the diversity …