Rotifers stimulate the specific uptake rate in lotic phototrophic biofilms

13C and 15N uptake measurements were carried out in the Indian sector of the Antarctic Ocean along a 66�30'E. transect. Integrated values ranged from 0.41 to 1.00 and from 0.03 to 0.12 mg-atom m-2 h-1 for inorganic carbon and nitrogen respectively. These low values were in contrast to the high nutrient concentrations and the total irradiation available. Nitrate-nitrogen concentrations for example were mostly above 20�g-atom l-1 and on-deck total irradiation integrated over the entire incubation period was on average 10 MJ m-2. Integrated values for particulate matter varied between 337.5 and 694.4 mg-atom m-2 for carbon and between 48.2 and 92.2 mg-atom m-2 for nitrogen. Carbon to nitrogen composition ratios of the particulate matter have been compared with the uptake ratios of the same elements. While euphotic zone profiles of the former ratio exhibited only small changes (6.0-8.1, all stations included), corresponding uptake ratios varied over a wide range (0.1-25.1). Generally, the latter ratio decreased with decreasing available radiation. Response curves of specific uptake rate for carbon and nitrogen to increasing available radiation were found to be hyperbolic in shape and yielded half-saturation constants ranging between 0.9 and 3.9% of surface quantum irradiance, or between 4.9 and 16.2 × 1021 quanta m-2 h-1, if expressed in absolute units. Specific uptake rate for nitrate was directly related to ambient water temperature along a north-south cross section, but this relationship may have been an indirect one as other factors were possibly involved (ammonium concentration for example). Maximum growth rates as doublings per day expected from water temperature were about an order of magnitude higher than the measured actual specific uptake rates for inorganic carbon and nitrogen. This was also observed in a culture of natural phytoplankton. However, measured growth rates obtained from cell counts in the same culture agreed very well with the calculated maximum expected growth rates. Phytoplankton cells from the shipboard culture continued to divide while decreasing the nutrient cell content and without a corresponding increase in specific nutrient uptake rate. The lack of intensive nutrient utilization reflected the field situation and the limiting factor could not be identified in the culture or in the field.

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99mTc Technetium Sulfide and the Scintillation Camera in the Rapid Diagnosis of Pericardial Effusion

Nuklearmedizin ◽

10.1055/s-0038-1624740 ◽

1971 ◽

Vol 10 (02) ◽

pp. 122-128

Author(s):

W. H. Blahd ◽

M. A. Winston ◽

G. T. Krishnamurthy ◽

P. B. Thomas ◽

E. Weiss

Keyword(s):

Pericardial Effusion ◽

Patient Positioning ◽

Rapid Diagnosis ◽

Scintillation Camera ◽

Technical Error ◽

Technetium 99M ◽

Sodium Pertechnetate ◽

Specific Uptake ◽

Speed Accuracy

SummaryBecause of its speed, accuracy, and reproducibility, radioisotopic angiocardiography appears to be the method of choice for the diagnosis of pericardial effusion. Technetium-99m sulfide is preferable to 99mTc sodium pertechnetate in these studies for the following reasons: (1) its specific uptake by the liver aids both in patient positioning and in the accuracy of diagnosis; and (2), studies can be repeated within 15—20 minutes should there be equiment or technical error.

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Quantitative analysis of renal function measured by simple renal uptake rate of 99mTc-DMSA scintigram

Journal of the Korean Radiological Society ◽

10.3348/jkrs.1991.27.5.727 ◽

1991 ◽

Vol 27 (5) ◽

pp. 727 ◽

Cited By ~ 2

Author(s):

Jong Wha Lee ◽

Min Yun Choi ◽

Tae Yong Moon ◽

Byung Soo Kim

Keyword(s):

Renal Function ◽

Quantitative Analysis ◽

Uptake Rate ◽

Renal Uptake

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Effect of N management approaches and planting densities on nitrogen accumulation by transplanted rice

Acta Agronomica Hungarica ◽

10.1556/aagr.53.2005.4.6 ◽

2005 ◽

Vol 53 (4) ◽

pp. 405-415 ◽

Cited By ~ 2

Author(s):

P. Janaki ◽

T. M. Thiyagarajan

Keyword(s):

Grain Yield ◽

Uptake Rate ◽

Aboveground Biomass ◽

N Uptake ◽

Planting Density ◽

Transplanted Rice ◽

The Mean ◽

N Uptake Rate ◽

Management Approaches ◽

N Management

Field experiments were conducted during 1998 and 1999 in June-September with rice variety ASD18 at the wetland farm, Tamil Nadu Agricultural University, Coimbatore, India to find out theeffect of N management approaches and planting densities on N accumulation by transplanted rice in a split plot design.The main plot consisted of three plant populations (33, 66 and 100 hills m-2) and the sub-plot treatments of five N management approaches. The results revealed thatthe average N uptake in roots and aboveground biomass progressively increased with growth stages. The mean root and aboveground biomass Nuptake were 26.1 to 130.6 and 6.4 to 17.8 kg ha-1, respectively. The N uptake of grain and straw was higher in theSesbania rostratagreen manuring + 150 kg N treatment, but it was not effective in increasing the grain yield. The mean total N uptake was found to be significantly lower at 33 hills m-2(76.9 kg ha-1) and increased with an increase in planting density (100.9 and 117.2 kg ha-1at 66 and 100 hills m-2density). N application had a significant influence on N uptake and the time course of N uptake in all the SPAD-guided N approaches. A significant regression coefficient was observed between the crop N uptake and grain yield. The relationship between cumulative N uptake at the flowering stage and the grain yield was quadratic at all three densities. The N uptake rate (µN) was maximum during the active tillering to panicle initiation period and declined sharply after that. In general, µNincreased with an increase in planting density and the increase was significant up to the panicle initiation to flowering period.thereafter, the N uptake rate was similar at densities of 66 and 100 hills m-2.

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Morphogenesis of Phototrophic Biofilms is Controlled by Hydraulic Constraints and Enabled by Architectural Plasticity

SSRN Electronic Journal ◽

10.2139/ssrn.3681993 ◽

2020 ◽

Author(s):

Anna Depetris ◽

Hannes Peter ◽

Ankur Deep Bordoloi ◽

Hippolyte Bernard ◽

Amin Niayifar ◽

...

Keyword(s):

Phototrophic Biofilms ◽

Architectural Plasticity

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Modeling of mass transfer in biofilms in oscillatory flow conditions using k-ɛ turbulence model

Water Science & Technology Water Supply ◽

10.2166/ws.2003.0104 ◽

2003 ◽

Vol 3 (1-2) ◽

pp. 201-207

Author(s):

H. Nagaoka ◽

T. Nakano ◽

D. Akimoto

Keyword(s):

Numerical Simulation ◽

Mass Transfer ◽

Turbulence Model ◽

Uptake Rate ◽

Oscillatory Flow ◽

Substrate Uptake ◽

Flow Conditions ◽

Mass Transfer Mechanism ◽

Substrate Uptake Rate ◽

Good Agreement

The objective of this research is to investigate mass transfer mechanism in biofilms under oscillatory flow conditions. Numerical simulation of turbulence near a biofilm was conducted using the low Reynold’s number k-ɛ turbulence model. Substrate transfer in biofilms under oscillatory flow conditions was assumed to be carried out by turbulent diffusion caused by fluid movement and substrate concentration profile in biofilm was calculated. An experiment was carried out to measure velocity profile near a biofilm under oscillatory flow conditions and the influence of the turbulence on substrate uptake rate by the biofilm was also measured. Measured turbulence was in good agreement with the calculated one and the influence of the turbulence on the substrate uptake rate was well explained by the simulation.

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Verification of anoxic phosphate uptake as the main biochemical mechanism of the “dephanox” process

Water Science & Technology ◽

10.2166/wst.1997.0365 ◽

1997 ◽

Vol 35 (10) ◽

pp. 87-94 ◽

Cited By ~ 7

Author(s):

R. Sorm ◽

J. Wanner ◽

R. Saltarelli ◽

G. Bortone ◽

A. Tilche

Keyword(s):

Activated Sludge ◽

Nutrient Removal ◽

Uptake Rate ◽

Phosphate Uptake ◽

Biochemical Mechanism ◽

Batch Experiments ◽

Batch Tests ◽

Genetic Probes ◽

Activated Sludge Systems ◽

Removal System

The phenomenon of anoxic phosphate uptake with simultaneous denitrification was studied. For this purpose kinetic batch tests have been carried out by using the activated sludge samples from three modifications of nutrient removal activated sludge systems: two based on an anaerobic-anoxic-oxic (A2/O) system and a third on an anaerobic-oxic (A/O) system. The results showed significant differences in anoxic phosphate uptake rate between activated sludge which was alternatively exposed to anoxic conditions and activated sludge from the A/O arrangement. These differences were also accompanied by different denitrification rates. Simultaneously with batch experiments the microscopic observation of activated sludge samples was carried out. Neisser and Gram stained samples showed clear differences in shape, size and distribution of polyphosphate accumulating bacteria between A2/O and A/O Processes. Moreover, experiments performed using genetic probes confirmed the differences in microbiological composition of activated sludge samples from different nutrient removal system arrangements.

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