Kinetics of accumulation of radioiodine by thyroid gland: longer time intervals

1962 ◽  
Vol 202 (1) ◽  
pp. 189-192 ◽  
Author(s):  
Seymour H. Wollman
Keyword(s):  
Simple Model ◽  
Thyroid Gland ◽  
Blood Serum ◽  
Model Analysis ◽  
Time Interval ◽  
Time Intervals ◽  
Rate Of Increase ◽  
Corrected Data ◽  
Almost All ◽  
Kinetics Of

The radioiodide and the protein-bound radioiodine (PBI131) concentrations in the thyroid gland and the serum radioiodide concentrations in mice and rats were measured at various time intervals (up to 25 hr) after injection of radioiodide. The ratio of the radioiodide concentrations in the thyroid gland and serum (T/S) increased progressively with the time interval after injection. If it is assumed that a small but constant fraction of the thyroid PBI131 decomposed during the fractionation of the thyroid I131, the corrected thyroid radiodiode concentration yielded a constant T/S up to 4 hr after injection and the rate of increase of the thyroid PBI131 was proportional to the thyroid radioiodide concentration. The corrected data were therefore consistent with a previously published simple model. Analysis of the source of thyroid radioiodide indicated that at 4 hr after injection almost all was derived from blood serum, but at 25 hr most could have been derived from thyroidal PBI131 by physiological degradation.

Kinetics of accumulation of radioiodine by thyroid gland: short time intervals

1962 ◽  
Vol 202 (1) ◽  
pp. 182-188 ◽  
Author(s):  
Seymour H. Wollman ◽  
Franklin E. Reed
Keyword(s):  
Experimental Data ◽  
Thyroid Gland ◽  
Blood Serum ◽  
Compartment Model ◽  
Time Intervals ◽  
Binding Process ◽  
Three Compartment Model ◽  
Short Time ◽  
Rats And Mice ◽  
Kinetics Of

The protein-bound radioiodine and radioiodide concentrations in the thyroid gland and serum radioiodide concentrations in rats and mice were measured between 3 and 16 min after injection of radioiodide. The data were compared with predictions of a simple open three-compartment model of the thyroid gland. The model generally fitted the experimental data well. The amount of radioiodine incorporated into organic binding each minute varied from one-third to twice the amount of radioiodide in the thyroid, depending on diet. The data were also compared with previously published results on duplicate sets of animals in which the formation of protein-bound iodine was acutely blocked by a goitrogen. The ability of the thyroid to maintain a concentration of radioiodide elevated above that of blood serum was much less when binding was permitted than when blocked and seems to be due to removal of thyroid radioiodide by the binding process and, in addition in the rat, by increased transport of radioiodide from thyroid to blood.

The Imposition of Empirical Acceptability Conditions on Sequences of Single Measurements

1969 ◽  
Vol 24 (1) ◽  
pp. 86-96 ◽  
Author(s):  
Paul A. Benioff
Keyword(s):  
Quantum Mechanics ◽  
Classical Mechanics ◽  
Physical Principle ◽  
Small Time ◽  
Time Interval ◽  
Single Measurement ◽  
Time Intervals ◽  
Regression Problem ◽  
Expectation Value ◽  
Almost All

AbstractHere, some difficulties resulting from the application of any empirical acceptability conditions on sequences of single measurements are investigated. In particular, the often used acceptability requirement that each single measurement be made under the "same conditions" is discussed. In quantum mechanics, this means that each single measurement is made of the same physical quantity on a system in a ensemble of identically prepared systems. One of the resultant difficulties is that such an application leads to an infinite regression of sequences of single measurements. That is, it does not account for the fact that an observer must start the process of measurement or knowledge acquisition. Furthermore, it is seen that there are some basic sequences of single measurements for which an observer can not possibly know at the outset that the "same condition" requirements are satisfied. These include those measurements by which the homogeneity of space-time is tested. The possible relevance of these difficulties to physics is shown by first considering two possi­bilities of avoiding these difficulties. One is that the "same condition" requirements can be given the weaker interpretation that there be no physical principle forbidding an observer from knowing in terms of limit empirical means, that they are satisfied at the outset of any sequence. This gets rid of the infinite regression problem as it does not mean that an observer must know in fact that these requirements are satisfied. The other possibility is that if physics does not forbid one in principle from measuring an expectation value in an arbitrarily small time interval then both the basic sequence as well as those by which one knows the "same" requirements are satisfied can be relegated to arbitrarily small time intervals. As far as physics is concerned, then the epistemological difficulties while existing in these small intervals, do not exist for other times, or almost all time. It is then shown that quantum mechanics, as distinct from classical mechanics, and the special relativity require that an infinite time interval is necessary to measure, as a limit mean, any expectation value. Thus physics denies both the above possibilities as it forbids an observer from knowing even in principle, by any finite time that the "same" requirements are satisfied. Also, physics forbids the relegation of the epistemological problems to arbitrarily small time intervals.

Diagnosis of Rolling Bearing by Measuring Time Interval of AE Generation

1999 ◽  
Vol 121 (3) ◽  
pp. 468-472 ◽  
Author(s):  
Takeo Yoshioka ◽  
Atsushi Korenaga ◽  
Hiroki Mano ◽  
Takashi Yamamoto
Keyword(s):  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Rolling Bearing ◽  
Rolling Contact ◽  
Time Interval ◽  
Measuring Time ◽  
Time Intervals ◽  
Measured Time ◽  
Ae Signal ◽  
Kinetics Of

We have developed a new method for measuring time intervals of Acoustic Emission (AE) generation for diagnosis of a radial rolling bearing. The method makes the AE signal itself a trigger of the oscillation of the clock pulse and measures the time interval of AE generation by integration of the clock pulses. The measurement device consists of the threshold, clock, time interval measurement and memory circuit, and was applied to rolling contact fatigue experiments. It was confirmed by the experiments that the measured time intervals of AE generation on the inner raceway or the ball agreed with the value calculated based on the kinetics of the rolling bearing. Moreover, we could identify the elements in which a fatigue crack was propagating by the method before the spalling appeared. The identified elements agreed with the failed elements.

scholarly journals THE FORMATION OF FIBRILS FROM COLLAGEN SOLUTIONS

1961 ◽  
Vol 9 (1) ◽  
pp. 193-209 ◽  
Author(s):  
M. K. Keech
Keyword(s):  
Fiber Formation ◽  
Time Interval ◽  
Electron Microscopic ◽  
Time Intervals ◽  
Human Dermis ◽  
Varying Length ◽  
Kinetics Of ◽  
Rna And Dna ◽  
Soluble Components

The kinetics of collagen reprecipitation from solutions of salt-extracted calf dermis in the presence of small amounts of mucopolysaccharide and nucleic acids (0.005 per cent in the final reaction mixture) has been reported by Wood (1960). The present paper is a parallel study using the same materials, and describes the electron microscopic (EM) morphology of the collagen precipitates replicated after 24 hours at room temperature. Satisfactory, uncontaminated EM preparations were obtained which showed that all the deposits were fibrous and bore the 640 A cross-banding characteristic of collagen except some narrow, background fibrils 200 to 1000 A wide precipitated in the presence of heparin. These exhibited fine striations about 220 A apart. Chondroitin sulfate greatly increased the rate of precipitation to give a deposit of low optical density consisting of narrow, rigid, discrete fibrils resembling fresh dermis. In contrast, heparin prevented macroscopic gelation, delayed precipitation, and only produced a scanty deposit of abnormal, short, wide, striated tactoids and compound fibers of varying length. The control preparations and the deposits formed in the presence of hyaluronic acid were intermediate between these two extremes. Delayed precipitation was associated with a coarser deposit and aggregation of the fibrils. A duplicate series of deposits precipitated in the presence of RNA and DNA, together with their controls, were examined after ½, 1, 1½, 3, 9, and 24 hours. One set employed an acetic extract of whole calf dermis and the other salt-extracted dermis. The presence of 0.005 per cent DNA in the reaction mixture markedly delayed collagen precipitation with the slow formation of abnormal, short, wide tactoids and compound fibers. RNA also interfered with the quantity and quality of the deposits which contained far less collagen resembling unfixed, normal, adult human dermis, than the controls at the corresponding time intervals. Comparison of the experiments employing whole calf dermis with those employing the salt-extracted material demonstrated that at every time interval in all the experiments the deposits were retarded when salt-extracted dermis was used. This suggests that the salt-soluble components of the dermis play a part in fiber formation.

Description of a Simple Model for the Study of Bone Calcium Metabolism

1980 ◽  
Vol 19 (01) ◽  
pp. 11-15
Author(s):  
G. Roncari ◽  
L. Rapisardi ◽  
L. Conte ◽  
G. Pedroli
Keyword(s):  
Simple Model ◽  
Calcium Metabolism ◽  
Good Description ◽  
Radioactive Tracer ◽  
Normal Subjects ◽  
Bone Diseases ◽  
Compartment System ◽  
Bone Calcium ◽  
Finite Period ◽  
Kinetics Of

A simple model for the study of bone calcium metabolism is proposed. It describes the kinetics of a radioactive tracer in terms of an open single compartment system with an expanding volume for a finite period of time. In addition to the simplicity of the hypotheses introduced, the model is able to give a good description of the biological processes which regulate calcium kinetics. Moreover the functional parameters can be easily calculated, even just graphically. 15 normal subjects and 22 patients affected by various bone diseases were studied. The results were compared with those obtained by using the model proposed by Burkinshaw et al. and the method described by Reeve et al.

METABOLIC STUDIES WITH 131I-LABELED THYROXINE. II.

1963 ◽  
Vol 44 (3) ◽  
pp. 475-480 ◽  
Author(s):  
R. Grinberg
Keyword(s):  
Spinal Cord ◽  
Central Nervous System ◽  
Nervous System ◽  
Optic Nerve ◽  
Pituitary Gland ◽  
Time Interval ◽  
Time Intervals ◽  
Pituitary Glands ◽  
The Central Nervous System ◽  
Tentative Explanation

ABSTRACT Radiologically thyroidectomized female Swiss mice were injected intraperitoneally with 131I-labeled thyroxine (T4*), and were studied at time intervals of 30 minutes and 4, 28, 48 and 72 hours after injection, 10 mice for each time interval. The organs of the central nervous system and the pituitary glands were chromatographed, and likewise serum from the same animal. The chromatographic studies revealed a compound with the same mobility as 131I-labeled triiodothyronine in the organs of the CNS and in the pituitary gland, but this compound was not present in the serum. In most of the chromatographic studies, the peaks for I, T4 and T3 coincided with those for the standards. In several instances, however, such an exact coincidence was lacking. A tentative explanation for the presence of T3* in the pituitary gland following the injection of T4* is a deiodinating system in the pituitary gland or else the capacity of the pituitary gland to concentrate T3* formed in other organs. The presence of T3* is apparently a characteristic of most of the CNS (brain, midbrain, medulla and spinal cord); but in the case of the optic nerve, the compound is not present under the conditions of this study.

scholarly journals Neural Network Approach for Global Solar Irradiance Prediction at Extremely Short-Time-Intervals Using Particle Swarm Optimization Algorithm

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1213
Author(s):  
Ahmed Aljanad ◽  
Nadia M. L. Tan ◽  
Vassilios G. Agelidis ◽  
Hussain Shareef
Keyword(s):  
Neural Networks ◽  
Particle Swarm Optimization ◽  
Solar Irradiance ◽  
Particle Swarm ◽  
Time Interval ◽  
Time Intervals ◽  
Swarm Optimization ◽  
Backpropagation Neural Networks ◽  
Proposed Model ◽  
Short Time

Hourly global solar irradiance (GSR) data are required for sizing, planning, and modeling of solar photovoltaic farms. However, operating and controlling such farms exposed to varying environmental conditions, such as fast passing clouds, necessitates GSR data to be available for very short time intervals. Classical backpropagation neural networks do not perform satisfactorily when predicting parameters within short intervals. This paper proposes a hybrid backpropagation neural networks based on particle swarm optimization. The particle swarm algorithm is used as an optimization algorithm within the backpropagation neural networks to optimize the number of hidden layers and neurons used and its learning rate. The proposed model can be used as a reliable model in predicting changes in the solar irradiance during short time interval in tropical regions such as Malaysia and other regions. Actual global solar irradiance data of 5-s and 1-min intervals, recorded by weather stations, are applied to train and test the proposed algorithm. Moreover, to ensure the adaptability and robustness of the proposed technique, two different cases are evaluated using 1-day and 3-days profiles, for two different time intervals of 1-min and 5-s each. A set of statistical error indices have been introduced to evaluate the performance of the proposed algorithm. From the results obtained, the 3-days profile’s performance evaluation of the BPNN-PSO are 1.7078 of RMSE, 0.7537 of MAE, 0.0292 of MSE, and 31.4348 of MAPE (%), at 5-s time interval, where the obtained results of 1-min interval are 0.6566 of RMSE, 0.2754 of MAE, 0.0043 of MSE, and 1.4732 of MAPE (%). The results revealed that proposed model outperformed the standalone backpropagation neural networks method in predicting global solar irradiance values for extremely short-time intervals. In addition to that, the proposed model exhibited high level of predictability compared to other existing models.

Real-World Experience with Artificial Intelligence-Based Triage in Transferred Large Vessel Occlusion Stroke Patients

2021 ◽  
pp. 1-6
Author(s):  
Jacob R. Morey ◽  
Xiangnan Zhang ◽  
Kurt A. Yaeger ◽  
Emily Fiano ◽  
Naoum Fares Marayati ◽  
...  
Keyword(s):  
Artificial Intelligence ◽  
Clinical Outcomes ◽  
Warning System ◽  
Large Vessel ◽  
Time Interval ◽  
Large Vessel Occlusion ◽  
Time Intervals ◽  
Vessel Occlusion ◽  
Left Behind ◽  
Stroke Center

<b><i>Background and Purpose:</i></b> Randomized controlled trials have demonstrated the importance of time to endovascular therapy (EVT) in clinical outcomes in large vessel occlusion (LVO) acute ischemic stroke. Delays to treatment are particularly prevalent when patients require a transfer from hospitals without EVT capability onsite. A computer-aided triage system, Viz LVO, has the potential to streamline workflows. This platform includes an image viewer, a communication system, and an artificial intelligence (AI) algorithm that automatically identifies suspected LVO strokes on CTA imaging and rapidly triggers alerts. We hypothesize that the Viz application will decrease time-to-treatment, leading to improved clinical outcomes. <b><i>Methods:</i></b> A retrospective analysis of a prospectively maintained database was assessed for patients who presented to a stroke center currently utilizing Viz LVO and underwent EVT following transfer for LVO stroke between July 2018 and March 2020. Time intervals and clinical outcomes were compared for 55 patients divided into pre- and post-Viz cohorts. <b><i>Results:</i></b> The median initial door-to-neuroendovascular team (NT) notification time interval was significantly faster (25.0 min [IQR = 12.0] vs. 40.0 min [IQR = 61.0]; <i>p</i> = 0.01) with less variation (<i>p</i> &#x3c; 0.05) following Viz LVO implementation. The median initial door-to-skin puncture time interval was 25 min shorter in the post-Viz cohort, although this was not statistically significant (<i>p</i> = 0.15). <b><i>Conclusions:</i></b> Preliminary results have shown that Viz LVO implementation is associated with earlier, more consistent NT notification times. This application can serve as an early warning system and a failsafe to ensure that no LVO is left behind.

scholarly journals Optimal Perturbations of an Oceanic Vortex Lens

Fluids ◽  
2018 ◽  
Vol 3 (3) ◽  
pp. 63 ◽  
Author(s):  
Thomas Meunier ◽  
Claire Ménesguen ◽  
Xavier Carton ◽  
Sylvie Le Gentil ◽  
Richard Schopp
Keyword(s):  
Normal Mode ◽  
Growth Rates ◽  
Time Interval ◽  
Time Intervals ◽  
Horizontal Structure ◽  
Azimuthal Wave ◽  
Wave Numbers ◽  
Non Linear ◽  
Long Time ◽  
Short Time

The stability properties of a vortex lens are studied in the quasi geostrophic (QG) framework using the generalized stability theory. Optimal perturbations are obtained using a tangent linear QG model and its adjoint. Their fine-scale spatial structures are studied in details. Growth rates of optimal perturbations are shown to be extremely sensitive to the time interval of optimization: The most unstable perturbations are found for time intervals of about 3 days, while the growth rates continuously decrease towards the most unstable normal mode, which is reached after about 170 days. The horizontal structure of the optimal perturbations consists of an intense counter-shear spiralling. It is also extremely sensitive to time interval: for short time intervals, the optimal perturbations are made of a broad spectrum of high azimuthal wave numbers. As the time interval increases, only low azimuthal wave numbers are found. The vertical structures of optimal perturbations exhibit strong layering associated with high vertical wave numbers whatever the time interval. However, the latter parameter plays an important role in the width of the vertical spectrum of the perturbation: short time interval perturbations have a narrow vertical spectrum while long time interval perturbations show a broad range of vertical scales. Optimal perturbations were set as initial perturbations of the vortex lens in a fully non linear QG model. It appears that for short time intervals, the perturbations decay after an initial transient growth, while for longer time intervals, the optimal perturbation keeps on growing, quickly leading to a non-linear regime or exciting lower azimuthal modes, consistent with normal mode instability. Very long time intervals simply behave like the most unstable normal mode. The possible impact of optimal perturbations on layering is also discussed.

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