Bone Formation and Inhibition of Bone Loss by Dynamic Muscle Stimulation With Altered Interstitial Fluid Pressure

2007 ◽  
Author(s):  
Yi-Xian Qin ◽  
Hoyan Lam
Keyword(s):  
Fluid Flow ◽  
Interstitial Fluid ◽  
Fluid Pressure ◽  
Tissue Level ◽  
Bone Strain ◽  
Bone Fluid Flow ◽  
Muscle Dynamics ◽  
Key Players ◽  
Flow Through ◽  
Bone Physiology

Tissue-level mechanisms and functions, including bone strain and muscle, are the potential key players in bone physiology and adaptation [1,2,3]. However, the mechanisms are not yet fully understood. Exercise such as muscle contraction appears to increase blood flow to the skeletal tissues, i.e., bone and muscle. These evidences imply that bone fluid flow induced by muscle dynamics may be an important role in regulating fluid flow through coupling of muscle and bone via microvascular system.

Initiation and Extension of Hydraulic Fractures in Rocks

1967 ◽  
Vol 7 (03) ◽  
pp. 310-318 ◽  
Author(s):  
Bezalel Haimson ◽  
Charles Fairhurst
Keyword(s):  
Fluid Flow ◽  
Hydraulic Fracturing ◽  
Cross Section ◽  
Elastic Constants ◽  
Fluid Pressure ◽  
Principal Stresses ◽  
Regional Stress ◽  
Flow Through ◽  
Elastic Rock ◽  
Regional Stresses

Abstract A criterion is proposed for the initiation of vertical hydraulic fracturing taking into consideration the three stress fields around the wellbore. These fields arise fromnonhydrostatic regional stresses in earththe difference between the fluid pressure in the wellbore and the formation fluid pressure andthe radial fluid flow through porous rock from the wellbore into the formation due to this pressure difference. The wellbore fluid pressure required to initiate a fracture (assuming elastic rock and a smooth wellbore wall) is a function o/ the porous elastic constants of the rock, the two unequal horizontal principal regional caresses, the tensile strength of the rock and the formation fluid pressure. A constant injection rate will extend the fracture to a point where equilibrium is reached and then, to keep the fracture open, the pressure required is a function of the porous elastic constants of the rock, the component of the regional stress normal to the plane of the fracture, the formation fluid pressure and the dimensions of the crack. The same expression may also be used to estimate the vertical fracture width, provided all other variables are known. The derived equations for the initiation and extension pressures in vertical fracturing may be employed to solve for the two horizontal, regional, principal stresses in the rock. Introduction Well stimulation by hydraulic fracturing is a common practice today in the petroleum industry. However, this stimulation process is not a guaranteed success; hence, the deep interest shown by the petroleum companies in better 'understanding the mechanism that brings about rock fracturing, fracture extension and productivity increase. Geologists and mining people became interested in hydraulic fracturing from a different point of view: the method may possibly be employed to determine the magnitude and direction of the principal stresses of great depth. Numerous articles in past years have dealt with the theory of hydraulic fracturing, but they all seem to underestimate the effect of stresses around the wellbore due to penetration of some of the injected fluid into the porous formation. Excellent papers on stresses in porous materials due to fluid flow have been published but no real attempt has been made to show the effect of these stresses in the form of a more complete criterion for vertical hydraulic fracturing initiation and extension. This paper is such an attempt. ASSUMPTIONS It is assumed that rock in the oil-bearing formation is elastic, porous, isotropic and homogeneous. The formation is under a nonhydrostatic state of regional stress with one of the principal regional stresses acting parallel to the vertical axis of the wellbore. This assumption is justified in areas where rock formations do not dip at steep angles and where the surface of the earth is relatively flat. This vertical principal regional stress equals the pressure of the overlying rock, i.e. S33= -pD where S33 is the total vertical principal stress (positive for tension), p is average density of the overlying material and D is the depth of the point where S 33 is calculated. The wellbore wall in the formation is considered to be smooth and circular in cross-section. The fluid flow through the porous elastic rock obeys Darcy's law. The whole medium is looked upon as an infinitely long cylinder with its axis along the axis of the wellbore. The radius of the cylinder is also very large. Over the range of depth at which the oil-bearing formation occurs, it will be assumed that any horizontal cross-section of the cylinder is subjected to the same stress distribution, and likewise that it will deform in the same manner. SPEJ P. 310ˆ

Interstitial fluid pressure gradient measured by micropuncture in excised dog lung

1984 ◽  
Vol 56 (2) ◽  
pp. 271-277 ◽  
Author(s):  
J. Bhattacharya ◽  
M. A. Gropper ◽  
N. C. Staub
Keyword(s):  
Fluid Flow ◽  
Pressure Gradient ◽  
Pressure Difference ◽  
Airway Pressure ◽  
Interstitial Fluid ◽  
Fluid Pressure ◽  
Interstitial Fluid Pressure ◽  
Pleural Pressure ◽  
Alveolar Wall ◽  
Fluid Filtration

We have directly measured lung interstitial fluid pressure at sites of fluid filtration by micropuncturing excised left lower lobes of dog lung. We blood-perfused each lobe after cannulating its artery, vein, and bronchus to produce a desired amount of edema. Then, to stop further edema, we air-embolized the lobe. Holding the lobe at a constant airway pressure of 5 cmH2O, we measured interstitial fluid pressure using beveled glass micropipettes and the servo-null method. In 31 lobes, divided into 6 groups according to severity of edema, we micropunctured the subpleural interstitium in alveolar wall junctions, in adventitia around 50-micron venules, and in the hilum. In all groups an interstitial fluid pressure gradient existed from the junctions to the hilum. Junctional, adventitial, and hilar pressures, which were (relative to pleural pressure) 1.3 +/- 0.2, 0.3 +/- 0.5, and -1.8 +/- 0.2 cmH2O, respectively, in nonedematous lobes, rose with edema to plateau at 4.1 +/- 0.4, 2.0 +/- 0.2, and 0.4 +/- 0.3 cmH2O, respectively. We also measured junctional and adventitial pressures near the base and apex in each of 10 lobes. The pressures were identical, indicating no vertical interstitial fluid pressure gradient in uniformly expanded nonedematous lobes which lack a vertical pleural pressure gradient. In edematous lobes basal pressure exceeded apical but the pressure difference was entirely attributable to greater basal edema. We conclude that the presence of an alveolohilar gradient of lung interstitial fluid pressure, without a base-apex gradient, represents the mechanism for driving fluid flow from alveoli toward the hilum.

Seepage Mechanics Mechanism of Undercompacted Mudstone's Formation

2013 ◽  
Vol 459 ◽  
pp. 693-697 ◽  
Author(s):  
Chong Feng ◽  
Hua Cai
Keyword(s):  
Fluid Flow ◽  
Flow Regime ◽  
Oil And Gas ◽  
Fluid Pressure ◽  
Fluid Flows ◽  
Pore Fluid ◽  
Pore Fluid Pressure ◽  
Flow Through ◽  
Physical Quantities ◽  
Practical Sense

Buried mudstones general have undercompacted phenomenon. Undercompacted mudstones have the characteristics that the porosity and pore fluid pressure are abnormal bigger. In order to disclosure the seepage mechanics mechanism of undercompacted mudstones formation, this paper has summed up the seepage mechanics relationship when fluid flows through the mudstone, and has verified the relationships between the key physical quantities with the minimal pressure (pressure that can let the fluid flow in the mudstone) by the experiments in physics. This paper has also analysis the formations process of undercompacted mudstone. The result shows that, the flow regime of fluid in the mudstone is the low speed seepage, and it is not applicable by Darcy equation; the fluid what flow through the thick and heavy compacted mudstone has the big minimal pressure. At the beginning or during the deposit, the rule of fluid flow in the mudstone decides that the fluid inside of the mudstone is more difficult to flow out than the fluid surface of the mudstone, and the inside mudstone becomes undercompacted. Because of the undercompacted mudstone is more important for the exploration of oil and gas, it has theoretic and practical sense to analysis the formations mechanism of the undercompacted mudstone.

scholarly journals Investigating low-velocity fluid flow in tumours using convection-MRI

2017 ◽  
Author(s):  
Simon Walker-Samuel ◽  
Thomas A. Roberts ◽  
Rajiv Ramasawmy ◽  
Jake Burrell ◽  
S. Peter Johnson ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Interstitial Fluid ◽  
Fluid Pressure ◽  
Interstitial Fluid Pressure ◽  
Tumor Xenograft ◽  
Low Velocity ◽  
Targeting Therapy ◽  
Vascular Flow ◽  
Velocity Flow ◽  
Magnetic Resonance Imaging Mri

AbstractSeveral distinct fluid flow phenemena occur in solid tumours, including intravascular blood flow and interstitial convection. To probe low-velocity flow in tumors resulting from raised interstitial fluid pressure, we have developed a novel magnetic resonance imaging (MRI) technique named convection-MRI. It uses a phase-contrast acquisition with a dual-inversion vascular nulling preparation to separate intra- and extra-vascular flow. Here, we report the results of experiments in flow phantoms, numerical simulations and tumor xenograft models to investigate the technical feasibility of convection-MRI. We report a good correlation between estimates of effective fluid pressure from convection-MRI with gold-standard, invasive measurements of interstitial fluid pressure in mouse models of human colorectal carcinoma and show that convection-MRI can provide insights into the growth and response to vascular-targeting therapy in colorectal cancers.

Anabolic Fluid Flow as Dependent on It Dose and Frequency in Bone Formation and Inhibition of Bone Loss

2004 ◽  
Author(s):  
Yi-Xian Qin ◽  
Tamara Kaplan ◽  
Hoyan Lam
Keyword(s):  
Fluid Flow ◽  
Adaptive Response ◽  
Interstitial Fluid ◽  
Fluid Pressure ◽  
Bone Adaptation ◽  
Fluid Loading ◽  
Interstitial Fluid Flow ◽  
Flow Rates ◽  
Dynamic Components ◽  
One Year

Anabolic response of bone to interstitial fluid flow is strongly dependent on the dynamic components of the fluid pressure, implying that fluid flow is a critical regulatory component to bone mass and morphology. While the fluid stimulus can be potentially applied for therapeutic in promoting turnover, the hypothesis of fluid induced bone adaptation was evaluated in an avian ulna model using varied flow rates and magnitudes. Total of 12 one-year old male avian animals was used in this study. A sinusoidal fluid pressure was applied to the experimental ulna 10 min/day for 4 weeks. Three experimental groups of loading were performed at 1 and 30 Hz of fluid loading. The results reveal an increase of 22.7%±7.2 in trabecular volume for group of 30 Hz, 76mmHg loading, while it had only 0.5 % increase at 1Hz, 76 mmHg loading. Under physiologic fluid pressure, a higher flow rate of stimuli generates much higher remodeling response than a lower rate of loading. This implies that bone turnover may be sensitive to the dynamic components of fluid flow, thereby initiating the adaptive response.

scholarly journals Bone strain magnitude is correlated with bone strain rate in tetrapods: implications for models of mechanotransduction

2015 ◽  
Vol 282 (1810) ◽  
pp. 20150321 ◽  
Author(s):  
B. R. Aiello ◽  
J. Iriarte-Diaz ◽  
R. W. Blob ◽  
M. T. Butcher ◽  
M. T. Carrano ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Strain Rate ◽  
Flow Rate ◽  
Structural Integrity ◽  
Tissue Level ◽  
Bone Adaptation ◽  
Bone Strain ◽  
Mechanical Stimuli ◽  
Fluid Flow Rate ◽  
Strain Magnitude

Hypotheses suggest that structural integrity of vertebrate bones is maintained by controlling bone strain magnitude via adaptive modelling in response to mechanical stimuli. Increased tissue-level strain magnitude and rate have both been identified as potent stimuli leading to increased bone formation. Mechanotransduction models hypothesize that osteocytes sense bone deformation by detecting fluid flow-induced drag in the bone's lacunar–canalicular porosity. This model suggests that the osteocyte's intracellular response depends on fluid-flow rate, a product of bone strain rate and gradient, but does not provide a mechanism for detection of strain magnitude. Such a mechanism is necessary for bone modelling to adapt to loads, because strain magnitude is an important determinant of skeletal fracture. Using strain gauge data from the limb bones of amphibians, reptiles, birds and mammals, we identified strong correlations between strain rate and magnitude across clades employing diverse locomotor styles and degrees of rhythmicity. The breadth of our sample suggests that this pattern is likely to be a common feature of tetrapod bone loading. Moreover, finding that bone strain magnitude is encoded in strain rate at the tissue level is consistent with the hypothesis that it might be encoded in fluid-flow rate at the cellular level, facilitating bone adaptation via mechanotransduction.

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