Atmospheric residence times and excess of unsupported 210Po in aerosol samples from the Kuwait bay-northern gulf

Chemosphere ◽  
2020 ◽  
Vol 261 ◽  
pp. 127690 ◽  
Author(s):  
A. Aba ◽  
A. Ismaeel ◽  
O. Al-Boloushi ◽  
H. Al-Shammari ◽  
A. Al-Boloushi ◽  
...  
Keyword(s):  
Residence Times ◽  
Kuwait Bay

Dosimetry with 188Re-labelled monoclonal anti-CD66 antibodies

2006 ◽  
Vol 45 (03) ◽  
pp. 134-138 ◽  
Author(s):  
T. Kull ◽  
N. M. Blumstein ◽  
D. Bunjes ◽  
B. Neumaier ◽  
A. K. Buck ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Bone Marrow ◽  
Gamma Camera ◽  
Absorbed Dose ◽  
Correlation Coefficients ◽  
Residence Times ◽  
Reliable Prediction ◽  
Red Bone Marrow ◽  
Antibody Preparation ◽  
Simplified Method

SummaryAim: For the therapeutic application of radiopharmaceuticals the activity is determined on an individual basis. Here we investigated the accuracy for a simplified assessment of the residence times for a 188Re-labelled anti-CD66 monoclonal antibody. Patients, methods: For 49 patients with high risk leukaemia (24 men, 25 women, age: 44 ± 12 years) the residence times were determined for the injected 188Re-labelled anti-CD66 antibodies (1.3 ± 0.4 GBq, 5–7 GBq/mg protein, >95% 188Re bound to the antibody) based on 5 measurements (1.5, 3, 20, 26, and 44 h p.i.) using planar conjugate view gamma camera images (complete method). In a simplified method the residence times were calculated based on a single measurement 3 h p.i. Results: The residence times for kidneys, liver, red bone marrow, spleen and remainder of body for the complete method were 0.4 ± 0.2 h, 1.9 ± 0.8 h, 7.8 ± 2.1 h, 0.6 ± 0.3 h and 8.6 ± 2.1 h, respectively. For all organs a linear correlation exists between the residence times of the complete method and the simplified method with the slopes (correlation coefficients R > 0.89) of 0.89, 0.99, 1.23, 1.13 and 1.09 for kidneys, liver, red bone marrow, spleen and remainder of body, respectively. Conclusion: The proposed approach allows reliable prediction of biokinetics of 188Re-labelled anti-CD66 monoclonal antibody biodistribution with a single study. Efficient pretherapeutic estimation of organ absorbed dose may be possible, provided that a more stable anti-CD66 antibody preparation is available.

Autecology of scum producing bacteria

1998 ◽  
Vol 37 (4-5) ◽  
pp. 527-530 ◽  
Author(s):  
Hilde Lemmer ◽  
George Lind ◽  
Margit Schade ◽  
Birgit Ziegelmayer
Keyword(s):  
Wastewater Treatment ◽  
Cell Surface ◽  
Wastewater Treatment Plants ◽  
Cell Surface Hydrophobicity ◽  
Surface Hydrophobicity ◽  
Residence Times ◽  
Loading Conditions ◽  
Emulsifying Activity ◽  
Substrate Preferences

Non-filamentous hydrophobic scum bacteria were isolated from scumming wastewater treatment plants (WWTP) by means of adhesion to hydrocarbons. They were characterized with respect to taxonomy, substrate preferences, cell surface hydrophobicity, and emulsification capability. Their role during flotation events is discussed. Rhodococci are selected by hydrolysable substrates and contribute to flotation both by cell surface hydrophobicity and emulsifying activity at long mean cell residence times (MCRT). Saprophytic Acinetobacter strains are able to promote flotation by hydrophobicity and producing emulsifying agents under conditions when hydrophobic substrates are predominant. Hydrogenophaga and Acidovorax species as well as members of the Cytophaga/Flavobacterium group are prone to proliferate under low loading conditions and contribute to flotation mainly by emulsification.

Smoothing of stationary random signal in continuous flow mixer with gamma-distribution of residence times

1985 ◽  
Vol 50 (11) ◽  
pp. 2545-2557
Author(s):  
Pavel Hasal ◽  
Vladimír Kudrna ◽  
Jitka Vyhlídková
Keyword(s):  
Theoretical Analysis ◽  
Gamma Distribution ◽  
Continuous Flow ◽  
Random Signal ◽  
Linear Filter ◽  
Residence Times ◽  
Statistical Parameters ◽  
Basic Parameters

The paper is focused on a theoretical analysis of the function of continuous flow mixer with the so-called gamma-distribution of fluid residence times, used as a linear filter smoothing undesirable fluctuations of input properties. A relation is derived expressing the degree of smoothing of the signal passing through the system, as a function of statistical parameters of this signal and of gamma-distribution of fluid-residence times in the mixer. The analysis of this relation leads to conclusions concerning the prediction of the operation of smoothing mixers or the design of their basic parameters.

On the time scales and structure of Lagrangian intermittency in homogeneous isotropic turbulence

2019 ◽  
Vol 867 ◽  
pp. 438-481 ◽  
Author(s):  
R. Watteaux ◽  
G. Sardina ◽  
L. Brandt ◽  
D. Iudicone
Keyword(s):  
Time Scales ◽  
Isotropic Turbulence ◽  
Flow Characteristics ◽  
Residence Times ◽  
Particle Trajectories ◽  
Local Flow ◽  
Available Energy ◽  
Homogeneous And Isotropic Turbulence ◽  
History Of ◽  
Optimum Manner

We present a study of Lagrangian intermittency and its characteristic time scales. Using the concepts of flying and diving residence times above and below a given threshold in the magnitude of turbulence quantities, we infer the time spectra of the Lagrangian temporal fluctuations of dissipation, acceleration and enstrophy by means of a direct numerical simulation in homogeneous and isotropic turbulence. We then relate these time scales, first, to the presence of extreme events in turbulence and, second, to the local flow characteristics. Analyses confirm the existence in turbulent quantities of holes mirroring bursts, both of which are at the core of what constitutes Lagrangian intermittency. It is shown that holes are associated with quiescent laminar regions of the flow. Moreover, Lagrangian holes occur over few Kolmogorov time scales while Lagrangian bursts happen over longer periods scaling with the global decorrelation time scale, hence showing that loss of the history of the turbulence quantities along particle trajectories in turbulence is not continuous. Such a characteristic partially explains why current Lagrangian stochastic models fail at reproducing our results. More generally, the Lagrangian dataset of residence times shown here represents another manner for qualifying the accuracy of models. We also deliver a theoretical approximation of mean residence times, which highlights the importance of the correlation between turbulence quantities and their time derivatives in setting temporal statistics. Finally, whether in a hole or a burst, the straining structure along particle trajectories always evolves self-similarly (in a statistical sense) from shearless two-dimensional to shear bi-axial configurations. We speculate that this latter configuration represents the optimum manner to dissipate locally the available energy.

059 Daridorexant: A dual, equipotent, and insurmountable antagonist of both orexin-1 and orexin-2 receptors

SLEEP ◽  
2021 ◽  
Vol 44 (Supplement_2) ◽  
pp. A25-A25
Author(s):  
Celia Mueller Grandjean ◽  
Manon Kiry ◽  
Catherine Vaillant ◽  
Oliver Nayler ◽  
John Gatfield
Keyword(s):  
Calcium Release ◽  
Brain Activity ◽  
Specific Treatment ◽  
Receptor Occupancy ◽  
Kinetic Properties ◽  
Receptor Subtypes ◽  
Residence Times ◽  
Binding Assays ◽  
Receptor System ◽  
Highly Effective

Abstract Introduction The orexin neuropeptide–receptor system is a central sleep and wake regulator in the brain. The two orexin receptor subtypes, OX1R and OX2R, are expressed either alone or together in all major wake-promoting brain areas. OX1R and OX2R activation by orexins causes elevation of intracellular calcium, which enhances synaptic transmission in secondary, monoaminergic wake- and arousal-promoting neurotransmitter circuits. Orexin receptor antagonists represent a novel and specific treatment of insomnia, which is different from classical therapy that more broadly inhibits brain activity via GABAA activation. Here we describe the molecular pharmacology of daridorexant, an orexin receptor antagonist which has proven highly effective in improving sleep and daytime functioning in insomnia patients. Methods Orexin-A(OxA)-induced calcium release assays in OX1R- and OX2R-expressing recombinant cell lines were applied to measure the antagonistic potency and kinetic properties of daridorexant in functional assays. Whole-cell competitive binding assays, using an orthosteric tracer were employed to determine the Ki of daridorexant. Comparisons were made with suvorexant and lemborexant. Results In OxA-induced calcium release assays with 2-h pre-incubation time, daridorexant displayed apparent Kb values of 0.5 nM (OX1R) and 0.8 nM (OX2R) with insurmountable antagonism on both receptors, demonstrating equipotent and highly effective functional inhibition of both receptor subtypes. On-target residence times of daridorexant (37oC) expressed as receptor occupancy half-lives (ROt1/2) were 4 min (OX1R) and 8 min (OX2R). In binding assays, daridorexant behaved as highly potent orthosteric antagonist. Also suvorexant behaved as dual insurmountable antagonist at OX1R/OX2R (appKb=0.7nM/1.0nM; ROt1/2=9 min/6 min) and as potent orthosteric antagonist in binding assays. Interestingly, lemborexant displayed a different interaction profile at OX1R/OX2R (appKb=13nM/0.4nM, ROt1/2<2min/<2min), i.e. it behaved as preferential OX2R antagonist with a very short on-target residence time and little insurmountability. Conclusion Daridorexant displays the desired target interaction profile of a dual, equipotent, and insurmountable antagonist of both OX1R and OX2R, which ensures equally efficient inhibition of both arousal-/wake-promoting receptor subtypes. Daridorexant′s on-target residence times are long enough to cause insurmountable inhibition, but short enough to avoid pharmacodynamic effects after drug elimination. Support (if any) Funded by Idorsia Pharmaceuticals Ltd.

High-frequency operation of pulsatile ventricular assist devices: A computational study on circular and elliptically shaped pumps

2019 ◽  
Vol 42 (12) ◽  
pp. 725-734 ◽  
Author(s):  
Christian Loosli ◽  
Stephan Rupp ◽  
Bente Thamsen ◽  
Mathias Rebholz ◽  
Gerald Kress ◽  
...  
Keyword(s):  
High Frequency ◽  
Flow Patterns ◽  
Ventricular Assist Devices ◽  
Shear Stresses ◽  
Residence Times ◽  
Pump Frequency ◽  
Ventricular Assist ◽  
Assist Devices ◽  
High Frequency Operation ◽  
Wall Shear

Pulsatile positive displacement pumps as ventricular assist devices were gradually replaced by rotary devices due to their large volume and high adverse event rates. Nevertheless, pulsatile ventricular assist devices might be beneficial with regard to gastrointestinal bleeding and cardiac recovery. Therefore, aim of this study was to investigate the flow field in new pulsatile ventricular assist devices concepts with an increased pump frequency, which would allow lower stroke volumes to reduce the pump size. We developed a novel elliptically shaped pulsatile ventricular assist devices, which we compared to a design based on a circular shape. The pump size was adjusted to deliver similar flow rates at pump frequencies of 80, 160, and 240 bpm. Through a computational fluid dynamics study, we investigated flow patterns, residence times, and wall shear stresses for different frequencies and pump sizes. A pump size reduction by almost 50% is possible when using a threefold pump frequency. We show that flow patterns inside the circular pump are frequency dependent, while they remain similar for the elliptic pump. With slightly increased wall shear stresses for higher frequencies, maximum wall shear stresses on the pump housing are higher for the circular design (42.2 Pa vs 18.4 Pa). The calculated blood residence times within the pump decrease significantly with increasing pump rates. A smaller pump size leads to a slight increase of wall shear stresses and a significant improvement of residence times. Hence, high-frequency operation of pulsatile ventricular assist devices, especially in combination with an elliptical shape, might be a feasible mean to reduce the size, without any expectable disadvantages in terms of hemocompatibility.

scholarly journals Effect of bathymetric changes on residence time in Buenaventura bay (Colombia)

DYNA ◽  
2019 ◽  
Vol 86 (211) ◽  
pp. 241-248
Author(s):  
Francisco Fernando Garcia Renteria ◽  
Mariela Patricia Gonzalez Chirino
Keyword(s):  
Finite Elements ◽  
Residence Time ◽  
Particle Tracking ◽  
Hydrodynamic Model ◽  
Residence Times ◽  
Particle Tracking Model ◽  
Tracking Model ◽  
Bathymetric Changes

In order to study the effects of dredging on the residence time of the water in Buenaventura Bay, a 2D finite elements hydrodynamic model was coupled with a particle tracking model. After calibrating and validating the hydrodynamic model, two scenarios that represented the bathymetric changes generated by the dredging process were simulated. The results of the comparison of the simulated scenarios, showed an important reduction in the velocities fields that allow an increase of the residence time up to 12 days in some areas of the bay. In the scenario without dredging, that is, with original bathymetry, residence times of up to 89 days were found.

Sign in / Sign up

Export Citation Format

Share Document