VARIATION SIMULATION OF RADON CONCENTRATION IN THE TISSUES AND ORGANS OF THE BODY BY AN ELECTRICAL CIRCUIT

2019 ◽  
Vol 187 (3) ◽  
pp. 390-401
Author(s):  
Milad Pirmoradi ◽  
Ali Negarestani ◽  
Amin Baghizadeh
Keyword(s):  
Cardiac Output ◽  
Human Body ◽  
Absorbed Dose ◽  
Electrical Circuit ◽  
The Body ◽  
Inert Gases ◽  
Inert Gas ◽  
Voltage Source ◽  
Red Marrow ◽  
Inhalation Rate

Abstract In this study, a new model based on electric circuit theory has been introduced to simulate the dynamics of radioactive chemically inert gases in the human body. For this manner, it is assumed that inert gas is transported through the body to various organs via the blood stream. In this simulation, a voltage source is equivalent to gas generation in the atmosphere, the conductivity is equivalent to the cardiac output of the organ, the capacitor capacitance is equivalent to the volume of blood or tissue and voltage across a capacitor is equivalent to the gas concentration in air or blood or a tissue. This simulation can be used to study the dynamics of any inert gas whose partition coefficients are known. We use this simulation to study the dynamics of radon in human body. The physiologically based pharmacokinetic (PBPK) model that describes the fate of radon in systemic tissue has been used for this simulation. Using this simulation, the effective dose equivalent resulting from inhalation of radon has been estimated. The calculated values agree with the previously reported value. Also, using the model, it has been shown that after inhalation of radon gas, absorbed dose has been decreased in different tissues by increasing the inhalation rate without radon. So that, by doubling the inhalation rate and the rate of cardiac output, the value of the absorbed dose has been decreased 11.88% in the adipose tissue, 25.49% in the red marrow tissue and 20.3% in the liver organ.

Inert gas-exchange theory using an electric analogue

1964 ◽  
Vol 19 (6) ◽  
pp. 1193-1198 ◽  
Author(s):  
W. W. Mapleson
Keyword(s):  
Alveolar Ventilation ◽  
The Body ◽  
Exchange Theory ◽  
Inert Gases ◽  
Inert Gas ◽  
Respiratory Pattern ◽  
Whole Body ◽  
High Solubility ◽  
Systematic Analysis ◽  
Inhaled Anesthetics

When an inert gas of moderate or high solubility in blood is inhaled, the rate at which the alveolar concentration rises toward the inspired concentration increases as the inspired concentration is increased. The only previous systematic analysis of whole-body uptake of inert gases to allow for this effect was restricted to a single, artificial, respiratory pattern and the numerical calculations had to be made on a digital computer. This paper develops the theory for a range of respiratory patterns and shows how the computations may be made on a slightly modified form of a simple electric analogue. It is shown that the rate of saturation of the body increases less markedly with inspired concentration if the inspired alveolar ventilation, rather than the expired alveolar ventilation, is kept constant during the saturation process. Conversely, washout is more rapid with a constant inspired ventilation than with a constant expired ventilation. The theory is extended to show how the uptake of one inert gas may substantially affect the uptake of another, administered simultaneously. uptake, distribution and elimination; induction; recovery; drugs; inhaled anesthetics; nitrous oxide; diethyl ether; halothane; computers; ventilation; concentration effect; alveolar ventilation Submitted on February 13, 1964

scholarly journals Lead: A concise review of its toxicity, mechanism and health effect

2021 ◽  
Vol 15 (1) ◽  
pp. 055-062
Author(s):  
Aliyu Haruna Sani ◽  
Musa Amanabo
Keyword(s):  
Human Body ◽  
Health Effect ◽  
Chemical Properties ◽  
Absorbed Dose ◽  
Lead Toxicity ◽  
The Body ◽  
Long Run ◽  
Environmental Disease ◽  
Route Of Exposure ◽  
Physical And Chemical

Heavy metal toxicity over the years has been proven to be a source of diverse health risks. Thou these metals, play certain biological roles, they are in excess amount get accumulated in the body and food chain displaying a chronic effect in the long run. Lead toxicity is an important environmental disease and its effects on the human body are devastating with its toxicity dependent upon the absorbed dose, the route of exposure as well as the duration of exposure. There is almost no function in the human body which is not affected by lead toxicity. Lead is highly persistent in the environment and because of its continuous use, its levels rise in almost every country particularly in developing countries like Nigeria where it occupies unique physical and chemical properties that make it suitable for a large number of applications. Various public health measures have been undertaken to control, prevent and treat lead toxicity occurring at various levels, such as occupational exposure, accidents and environmental factors. This article reviews the works listed in scientific literatures with recent updates regarding the toxicity of lead. Focus is also on the biomarkers of lead toxicity on the renal, hematological and oxidative stress conditions.

Cardiac output and mixed venous oxygen content measurements by a tracer bolus method: theory

1997 ◽  
Vol 83 (3) ◽  
pp. 884-896 ◽  
Author(s):  
Justin S. Clark ◽  
Yuxiang J. Lin ◽  
Michael J. Criddle ◽  
Antonio G. Cutillo ◽  
Adelbert H. Bigler ◽  
...  
Keyword(s):  
Cardiac Output ◽  
Oxygen Content ◽  
Practical Method ◽  
Parameter Extraction ◽  
Extraction Process ◽  
Inert Gases ◽  
Inert Gas ◽  
Venous Oxygen Content ◽  
Sinusoidal Input ◽  
Mixed Venous

Clark, Justin S., Yuxiang J. Lin, Michael J. Criddle, Antonio G. Cutillo, Adelbert H. Bigler, Fred L. Farr, and Attilio D. Renzetti, Jr. Cardiac output and mixed venous oxygen content measurements by a tracer bolus method: theory. J. Appl. Physiol. 83(3): 884–896, 1997.—We present a bolus method of inert-gas delivery to the lungs that facilitates application of multiple inert gases and the multiple inert-gas-exchange technique (MIGET) model to noninvasive measurements of cardiac output (CO) and central mixed venous oxygen content[Formula: see text]Reduction in recirculation error is made possible by 1) replacement of sinusoidal input functions with impulse inputs and 2) replacement of steady-state analyses with transient analyses. Recirculation error reduction increases the inert-gas selection to include common gases without unusually high (and difficult to find) tissue-to-blood partition coefficients for maximizing the systemic filtering efficiency. This paper also presents a practical method for determining the recirculation contributions to inert expired profiles in animals and determining their specific contributions to errors in the calculations of CO and[Formula: see text] from simulations applied to published ventilation-perfusion ratio (V˙/Q˙) profiles. Recirculation errors from common gases were found to be reducible to the order of 5% or less for both CO and[Formula: see text] whereas simulation studies indicate that measurement bias contributions from recirculation, V˙/Q˙ mismatch, and the V˙/Q˙ extraction process can be limited to 15% for subjects with severeV˙/Q˙ mismatch and high inspired oxygen fraction levels. These studies demonstrate a decreasing influence of V˙/Q˙ mismatch on parameter extraction bias as the number of inert gases are increased. However, the influence of measurement uncertainty on parameter extraction error limits improvement to six gases.

A new class of biophysical models for predicting the probability of decompression sickness in scuba diving

2007 ◽  
Vol 103 (2) ◽  
pp. 484-493 ◽  
Author(s):  
Saul Goldman
Keyword(s):  
Decompression Sickness ◽  
Risk Function ◽  
Central Compartment ◽  
The Body ◽  
Inert Gases ◽  
Inert Gas ◽  
Washout Rate ◽  
Peripheral Compartment ◽  
New Class ◽  
Better Than

Interconnected compartmental models have been used for decades in physiology and medicine to account for the observed multi-exponential washout kinetics of a variety of solutes (including inert gases) both from single tissues and from the body as a whole. They are used here as the basis for a new class of biophysical probabilistic decompression models. These models are characterized by a relatively well-perfused, risk-bearing, central compartment and one or two non-risk-bearing, relatively poorly perfused, peripheral compartment(s). The peripheral compartments affect risk indirectly by diffusive exchange of dissolved inert gas with the central compartment. On the basis of the accuracy of their respective predictions beyond the calibration regime, the three-compartment interconnected models were found to be significantly better than the two-compartment interconnected models. The former, on the basis of a number of criteria, was also better than a two-compartment parallel model used for comparative purposes. In these latter comparisons, the models all had the same number of fitted parameters (four), were based on linear kinetics, had the same risk function, and were calibrated against the same dataset. The interconnected models predict that inert gas washout during decompression is relatively fast, initially, but slows rapidly with time compared with the more uniform washout rate predicted by an independent parallel compartment model. If empirically verified, this may have important implications for diving practice.

Decompression outcome following saturation dives with multiple inert gases in rats

1985 ◽  
Vol 59 (5) ◽  
pp. 1503-1514 ◽  
Author(s):  
R. S. Lillo ◽  
E. T. Flynn ◽  
L. D. Homer
Keyword(s):  
Decompression Sickness ◽  
Equation Model ◽  
Hill Equation ◽  
The Body ◽  
Inert Gases ◽  
Inert Gas ◽  
Albino Rats ◽  
Experimental Conditions ◽  
Decompression Stress ◽  
Relative Potencies

This investigation examined the question of whether gas mixtures containing multiple inert gases provide a decompression advantage over mixtures containing a single inert gas. Unanesthetized male albino rats, Rattus norvegicus, were subjected to 2-h simulated dives at depths ranging from 145 to 220 fsw. At pressure, the rats breathed various He-N2-Ar-O2 mixtures (79.1% inert gas-20.9% O2); they were then decompressed rapidly (within 10 s) to surface pressures. The probability of decompression sickness (DCS), measured either as severe bends symptoms or death, was related to the experimental variables in a Hill equation model incorporating parameters that account for differences in the potencies of the three gases and the weight of the animal. The relative potencies of the three gases, which affect the total dose of decompression stress, were determined as significantly different in the following ascending order of potency: He less than N2 less than Ar; some of these differences were small in magnitude. With mixtures, the degree of decompression stress diminished as either N2 or Ar was replaced by He. No obvious advantage or disadvantage of mixtures over the least potent pure inert gas (He) was evident, although limits to the expectation of possible advantage or disadvantage of mixtures were defined. Also, model analysis did not support the hypothesis that the outcome of decompression with multiple inert gases in rats under these experimental conditions can be explained totally by the volume of gas accumulated in the body during a dive.

Calculation of the radiation doses occurring in the human body for inadvertent ingestion of soil and other soil exposure pathways

2003 ◽  
Vol 81 (11) ◽  
pp. 1303-1307
Author(s):  
F Öner ◽  
N T Okumuşoğlu
Keyword(s):  
Human Body ◽  
Absorbed Dose ◽  
Whole Body ◽  
Radiation Doses ◽  
Dose Calculations ◽  
Bone Surface ◽  
Soil Ingestion ◽  
Red Marrow ◽  
Soil Exposure ◽  
Effective Doses

We estimate the radiation doses in the human body, in the Gudalore region in India, following the inadvertent ingestion of soil and exposure to other soil pathways by measuring 232Th, 238U, and 40K. We estimate the equivalent dose in eleven different organs and the absorbed dose calculations for the whole body. The annual effective doses are calculated, the lowest is in Kariyasolai at 7.8 × 10–3 mSv whereas the highest is in Ponnur at 8.9 × 10–2 mSv. In all regions, the lowest equivalent doses through inadvertent soil ingestion are calculated in the kidney and thyroid whereas the highest doses are in the red marrow and on the bone surface. PACS No.: 87.50.–a

Uptake of cyclopropane by the human body

1959 ◽  
Vol 14 (6) ◽  
pp. 887-890 ◽  
Author(s):  
P. H. Sechzer ◽  
R. D. Dripps ◽  
H. L. Price
Keyword(s):  
Human Body ◽  
Human Subjects ◽  
The Body ◽  
Fair Agreement ◽  
Inert Gases ◽  
Tissue Mass ◽  
Saturation Process ◽  
Homogeneous Tissue ◽  
Expired Air

The uptake of cyclopropane was measured in 5 human subjects who breathed a 1% concentration of the gas in oxygen for periods ranging from 7 to 62 minutes. The measured concentrations of cyclopropane in end-expired air were compared with those predicted by Kety's equation ( Pharmacol. Rev. 3:1, 1951) describing the saturation process for inert gases. Although fair agreement was found between the measured and predicted data, it was noted that the measured values increased more rapidly than theory predicted. This difference apparently resulted from Kety's simplifying assumption that the body consists of a homogeneous tissue mass. Submitted on May 25, 1959

Approaches to assess the impact of nanoparticles on the human body

2020 ◽  
Vol 99 (5) ◽  
pp. 443-447
Author(s):  
Nikolay A. Kashuba
Keyword(s):  
Physicochemical Properties ◽  
Human Body ◽  
Size Range ◽  
Biological Systems ◽  
Absorbed Dose ◽  
The Body ◽  
Methodological Approaches ◽  
Working Day ◽  
The Impact

The analysis of the behavior of nanoparticles in aerosols, their aerodynamic peculiarities and interaction with microparticles was made. The features of nanoparticle cumulation in the air of the working area of industrial premises during the working day, as well as during two, or three-shifts working day are studied; the features of the nanoparticles aggregation in aerosol with their subsequent degeneration into microparticles and further sedimentation are examined. The features of the transcutaneous entry of nanoparticles into a human body are considered. It was pointed out that nanoparticles of various sizes can differ in their physicochemical properties, and, correspondingly, their influence on biological systems. Therefore, it is shown that in order to establish the toxicological hazard of nanoparticles, it is necessary to establish the most sensitive system and weight concentrations of nanoparticles, as well as their most dangerous size range, i.e. it is necessary to take into account the dispersion distribution of nanoparticles. It was demonstrated that the solubility of micro- and nanoparticles can be crucial for assessing their influence on the body in case of the body transcutaneous entry or by inhalation. Possible approaches to assessing the intensity of the effect of nanoparticles on the human body are considered. New methodological approaches to assessing the effect of nanoparticles on the human body are proposed. The complexity and features of the regulation of nanoparticles in the air of the working area are described. It has been proposed to take into account the value of the “absorbed dose” while assessing the effect of aerosols containing micro- and nanoparticles.

Influence of blood flow on cutaneous permeability to inert gas

1984 ◽  
Vol 57 (4) ◽  
pp. 1167-1172 ◽  
Author(s):  
Y. C. Lin ◽  
N. Kakitsuba ◽  
D. K. Watanabe ◽  
G. W. Mack
Keyword(s):  
Blood Flow ◽  
Ambient Temperature ◽  
Gas Diffusion ◽  
The Body ◽  
Inert Gases ◽  
Inert Gas ◽  
Human Hand ◽  
Cutaneous Blood Flow ◽  
Diffusion Distance ◽  
Cutaneous Blood

A thermally regulated Plexiglas chamber was designed for investigation of transcutaneous diffusion of N2 and helium (He) in the human hand. Influence of cutaneous blood flow in this process was studied simultaneously with gas diffusion measurements. Changes in cutaneous blood flow (Q, in ml X min-1 X 100 ml tissue-1) were effected by altering ambient temperature (T) from 20 to 40 degrees C (Q = 0.08 X 100.07T). We found that the rate of inert gas diffusion through human skin, expressed as conductance (G, in ml STPD X h-1 X m-2 X atm-1), increases exponentially as a function of blood flow, and was indistinguishable between He and N2 (G = 21.19 X 100.0124Q). The permeability, diffusion coefficient per unit diffusion distance (D/h, in cm/h), also rose exponentially as a function of blood flow. But permeability for He (D/h = 0.1748 X 100.0203Q) was greater than that for N2 (D/h = 0.1678 X 100.0114Q). As cutaneous blood flow rises, because of increased temperature, the apparent diffusion distance falls linearly for both N2 and He. The change is more prominent for He than for N2 diffusion. Estimated replacement time for the body stores of N2 by transcutaneous diffusion alone was shortened from 26.8 h at 31 degrees C to 15.1 h at 37 degrees C. It is suggested from this study that beneficial results may be derived during decompression procedure 1) by maintaining an appropriate transcutaneous pressure gradient of inert gases, and 2) by elevating ambient temperature.

How does increased cardiac output increase shunt in pulmonary edema?

1982 ◽  
Vol 53 (5) ◽  
pp. 1273-1280 ◽  
Author(s):  
P. H. Breen ◽  
P. T. Schumacker ◽  
G. Hedenstierna ◽  
J. Ali ◽  
P. D. Wagner ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Pulmonary Edema ◽  
Pulmonary Blood Flow ◽  
Inert Gases ◽  
Inert Gas ◽  
Gas Transfer ◽  
Output Increase ◽  
Air Ventilation ◽  
The Relationship

In pulmonary edema, the relationship between cardiac output (QT) and shunt (QS/QT) may be due to a diffusion barrier for O2 transfer (incomplete alveolar-capillary equilibration) or to redistribution of increased pulmonary blood flow toward edematous units. We compared transfer of O2 and multiple inert gases in the left (LLL) and right (RLL) lower lobes and in the whole lungs of eight dogs having oleic acid edema in LLL. When mean QT was increased from 3.0 to 5.5 l X min-1 during O2 ventilation, relative perfusion of LLL did not increase but QS/QT increased because LLL shunt increased from 56 to 78%. We conclude that increased pulmonary blood flow is not redistributed toward edematous regions, but we cannot exclude such redistribution within LLL and other slightly edematous lobes. In LLL, inert gas shunt and O2 shunt were not systematically different during O2 ventilation, and lobar venous PO2 measured during air ventilation was not different from that predicted by inert gas transfer. We conclude that diffusion limitation for O2 does not contribute to QS/QT or to the increase in QS/QT when QT increases. Conceivably, increased QT increased QS/QT by increasing edema or hematocrit in edematous regions.

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