Distensibility of small veins of the dog lung

1992 ◽  
Vol 73 (5) ◽  
pp. 2158-2165 ◽  
Author(s):  
A. al-Tinawi ◽  
A. V. Clough ◽  
D. R. Harder ◽  
J. H. Linehan ◽  
D. A. Rickaby ◽  
...  
Keyword(s):  
Vascular Resistance ◽  
Negative Correlation ◽  
Pressure Range ◽  
High Pressures ◽  
X Ray ◽  
Average Value ◽  
Isolated Lung ◽  
Weak Negative Correlation ◽  
Intravascular Pressure ◽  
Lung Lobes

To determine the distensibility of the intrapulmonary veins (250–2,900 microns diam) of the dog lung, we obtained X-ray angiograms from isolated lung lobes over a vascular pressure range of approximately 0–30 Torr. Over this pressure range the diameter vs. pressure curves tended to flatten out at the high pressures. In the pressure range of 0–19 Torr, we characterized the vessel distensibility by alpha (the ratio of the slope, beta, of the graph of diameter vs. intravascular pressure to the intercept, Do). The average value of alpha was approximately 1.2%/Torr. There was a weak negative correlation (r = -0.32) between alpha and Do. Infusion of enough norepinephrine to produce approximately 50% increase in total lobar vascular resistance produced a decrease in Do and alpha of approximately 33 and 32%, respectively.

Studying Mechanical Properties Of Thin Films Under High Pressures

1990 ◽  
Vol 188 ◽  
Author(s):  
B. C. Cai ◽  
D. Kuhlmann-Wilsdorf ◽  
R. B. Nelson
Keyword(s):  
Work Hardening ◽  
Deformation Behavior ◽  
Recrystallization Texture ◽  
Pressure Range ◽  
High Pressures ◽  
Sample Thickness ◽  
Thickness Effect ◽  
X Ray ◽  
Significant Difference ◽  
Shear Strains

ABSTRACTWork-hardening curves of aluminum foils and of stacks of O.1μm thick 22 ct. gold foils, deformed between rotating Bridgman anvils, have been obtained for pressures up to 1533 MPa and shear strains to 400,000%. No sample thickness effect has been found between 5μm and 3μm, nor any significant difference between homogeneous foils and multi-layer foils, but heat-treatments do affect the results, as apparently does the introduction of 50nm thick sputtered copper layers between stacks of gold foils. Increases of strength with pressure appear to be due to corresponding increases of the Peierls-Nabarro stress. X-ray evidence indicates the reorientation of the foils from an initial (001) recrystallization texture after rolling to the (111) texture that was to be expected. Ordinary deformation behavior is indicated throughout, except for a tendency for slight negative work-hardening in the lower pressure range. At the extreme, assuming homogeneous deformation, the foils thinned to 60nm.

X-ray diffraction study of HgBa2CuO4+δ at high pressures

1997 ◽  
Vol 12 (2) ◽  
pp. 106-112
Author(s):  
Eduardo J. Gonzalez ◽  
Winnie Wong-Ng ◽  
Gasper J. Piermarini ◽  
Christian Wolters ◽  
Justin Schwartz
Keyword(s):  
High Pressure ◽  
Bulk Modulus ◽  
Pressure Range ◽  
High Pressures ◽  
Anisotropy Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Anisotropic Elastic ◽  
High Pressure Study

An in situ high pressure study using energy dispersive X-ray diffraction has been carried out on the polycrystalline high-Tc superconductor, HgBa2CuO4+δ (Hg-1201), to study its phase stability under pressure and also to measure its compressibility and bulk modulus. No evidence of pressure-induced polymorphism was found in the pressure range investigated, i.e., from 0.1 MPa (1 atm) to 5 GPa. The compound exhibited anisotropic elastic properties. The axial compressibility along the c axis was measured to be (3.96±0.35)×10−3GPa−1 and along the a axis (3.42±0.13)×10−3GPa−1, corresponding to an anisotropy ratio of 1.16±0.11. The bulk modulus was determined to be (94.7±4.2) GPa and, assuming a Poisson's ratio of 0.2, Young's modulus was estimated to be (170±8) GPa.

Pulmonary capillary pressure in intact dog lungs

1978 ◽  
Vol 235 (5) ◽  
pp. H569-H573
Author(s):  
J. C. Gabel ◽  
R. E. Drake
Keyword(s):  
Capillary Pressure ◽  
Pulmonary Vascular Resistance ◽  
Vascular Resistance ◽  
Pressure Range ◽  
Gravimetric Method ◽  
Average Value ◽  
Pulmonary Capillary ◽  
Pulmonary Capillary Pressure

We used a gravimetric method to determine the ratio (gamma) of pulmonary venous to total pulmonary vascular resistance in intact dog lungs. From this ratio, pulmonary capillary pressure (Pc) can be calculated. The average value of gamma was 0.50 +/- 0.06 (mean +/- SD) in 10 dogs. We found no correlation between gamma and PO2, PCO2, pH, or hematocrit in the narrow ranges of these experiments. Over the capillary pressure range of 22.4--35.2 mmHg we found no correlation between gamma and Pc. The value of gamma found in this study is not significantly different from the value found in isolated perfused lungs.

Distributions of vascular pressure and resistance in the lung

1988 ◽  
Vol 64 (1) ◽  
pp. 274-284 ◽  
Author(s):  
C. A. Dawson ◽  
T. A. Bronikowski ◽  
J. H. Linehan ◽  
D. A. Rickaby
Keyword(s):  
Vascular Resistance ◽  
Local Minimum ◽  
Vascular Volume ◽  
Low Viscosity ◽  
Vascular Bed ◽  
Residual Capacity ◽  
Capillary Bed ◽  
Arteries And Veins ◽  
Intravascular Pressure ◽  
Lung Lobes

The low-viscosity bolus method was used to determine the longitudinal distributions of vascular resistance and intravascular pressure with respect to cumulative vascular volume from the lobar artery to the lobar vein in isolated dog lung lobes near functional residual capacity under zone 3 conditions. We found that the resistance distribution had two modes, a larger one upstream and a smaller one downstream from a local minimum. Over the range of vascular pressures studied the total vascular resistance decreased and the vascular volume increased with increasing vascular pressure. However, the shape of the normalized resistance distribution was independent of vascular pressure. Comparisons of the resistance distributions with the distributions of arterial, capillary, and venous volumes suggest that the modes represent regions of relatively high resistance proximal and distal to the capillary bed. These results are consistent with the concept that within the lobar vascular bed the highest resistance per unit blood volume is in the smallest arteries and veins, as suggested by morphometric data from other sources.

Tilting of semi-rigid GaF6 octahedra in GaF3 at high pressures

2017 ◽  
Vol 32 (S1) ◽  
pp. S69-S73
Author(s):  
Jens-Erik Jørgensen ◽  
Yaroslav Filinchuk ◽  
Vladimir Dmitriev
Keyword(s):  
High Pressure ◽  
Pressure Range ◽  
High Pressures ◽  
Sphere Packing ◽  
Volume Reduction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Compression Mechanism ◽  
Measured Pressure ◽  
Linear Compressibility

The VF3-type compound GaF3 has been studied by high-pressure angle-dispersive X-ray diffraction in the pressure range from 0.0001 to 10 GPa. The compression mechanism was found to be highly anisotropic. The c-axis shows little pressure dependence (≈0.4%), but exhibits negative linear compressibility up to ≈3 GPa where it achieves its maximum length. In contrast, the length of the a-axis is reduced by ≈8.8% at the highest measured pressure and an anomalous reduction in the linear compressibility is observed at 4 GPa. The zero pressure bulk modulus B0 was determined to B0 = 28(1) GPa. The compression mechanism of GaF3 is discussed in terms of deformation of an 8/3/c2 sphere-packing model. The volume reduction of GaF3 is mainly achieved through coupled rotations of the GaF6 octahedra within the entire measured pressure range, which reduces the volume of the cubooctahedral voids. In addition, the volume of the GaF6 octahedra also decreases for p ≲ 4.0 GPa, but remains constant above this pressure. The volume reduction of the GaF6 octahedra is accompanied by an increasing octahedral strain. Isosurfaces of the procrystal electron density are used for visualization of the cubooctahedral voids at different pressures.

Morphology and Structure of Oxides Grown on Aluminum In Superheated Steam

CORROSION ◽  
1965 ◽  
Vol 21 (7) ◽  
pp. 222-234 ◽  
Author(s):  
R. K. HART ◽  
J. K. MAURIN
Keyword(s):  
Electron Microscopy ◽  
Pressure Range ◽  
Superheated Steam ◽  
High Pressures ◽  
Pure Aluminum ◽  
X Ray Diffraction ◽  
X Ray ◽  
Powder Product ◽  
Morphology And Structure ◽  
Products Of Reaction

Abstract Four methods (light microscopy, electron microscopy, electron diffraction and X-ray diffraction) have been employed to identify and estimate the-products of reaction of pure aluminum with steam; in a few instances gravimetric measurements were also made. At temperatures between 400 and 450 C (752 and 842 F) and intermediate to high pressures aluminum disintegrated to a white powder product within 6 hours. This powder product was a mixture of α- and γ-alumina together with a small amount of aluminum. At higher temperatures and over the whole pressure range only γ-alumina was formed. The morphology of this material was threefold. A thin, highly resistant film rapidly grew to approximately 300 Å and drastically slowed down the reaction process. Outcropping from this film were oxide crystallites between 0.1 and 1.0 micron in size, as well as thin platelets which grew out from the surface as much as 10 microns. After reaction, specimen surfaces were found to contain numerous gas blisters as well as pits of various shapes and sizes. These pits ranged in size from less than 1 micron up to 300 microns and were located at grain boundaries as well as within metal grains.

Distensibility of small arteries of the dog lung

1991 ◽  
Vol 71 (5) ◽  
pp. 1714-1722 ◽  
Author(s):  
A. al-Tinawi ◽  
J. A. Madden ◽  
C. A. Dawson ◽  
J. H. Linehan ◽  
D. R. Harder ◽  
...  
Keyword(s):  
Transmural Pressure ◽  
Mean Values ◽  
Small Arteries ◽  
X Ray ◽  
Isolated Lung ◽  
Significant Difference ◽  
Pulmonary Arterial ◽  
The Mean ◽  
Lung Lobes

To obtain in situ measurements of the distensibility of small (100- to 1,000-microns-diam) pulmonary arterial vessels of the dog lung, X-ray angiograms were obtained from isolated lung lobes with the vascular pressure adjusted to various levels. The in situ diameter-pressure relationships were compared with the diameter-pressure relationships for small arteries that were dissected free from the lungs and cannulated with small glass pipettes for the measurement of diameter and transmural pressure. The diameter-vascular or diameter-transmural pressure curves from both in situ and cannulated vessels were sufficiently linear in the pressure range studied (0–30 Torr) that they could be characterized by linear regression to obtain estimates of D0, the diameter at zero vascular pressure, and beta, the change in diameter (micron) per Torr change in pressure. The vessel distensibility coefficient (alpha) was defined as alpha = beta/D0. The mean values of alpha were approximately 2.0 +/- 0.8%/Torr (SD) for the in situ vessels and 1.7 +/- 0.6%/Torr for the cannulated vessels, with no statistically significant difference between the two methods. The influence of vasoconstriction elicited by serotonin was evaluated in the in situ vessels. Serotonin-induced vasoconstriction caused a decrease in D0 and little change in alpha.

Capillary pressure and distribution of vascular resistance in isolated lung

1962 ◽  
Vol 202 (6) ◽  
pp. 1033-1036 ◽  
Author(s):  
Emilio Agostoni ◽  
Johannes Piiper
Keyword(s):  
Blood Flow ◽  
Vascular Resistance ◽  
Ringer Solution ◽  
External Pressure ◽  
Colloid Osmotic Pressure ◽  
Visceral Pleura ◽  
Average Value ◽  
Vascular Bed ◽  
Pulmonary Capillaries ◽  
Isolated Lung

Isolated lobes of dogs' lungs were perfused with constant nonpulsatile blood flow and expanded by negative external pressure. The pressure under which Ringer solution was absorbed through the visceral pleura was measured by an osmometric method. From this pressure and the plasma colloid osmotic pressure, the pressure in the subpleural capillaries was calculated. The average value of the latter was 8.8 mm Hg when the pulmonary artery and vein pressures were 13.4 and 1.8 mm Hg, respectively. Assuming that the pressure in the intrapulmonary capillaries is similar to that in the subpleural capillaries, the vascular resistance on the arterial and venous side of the effective midpoint of pulmonary capillaries could be calculated. The average vascular resistance on the venous side was found to be 60% of the total intrapulmonary vascular resistance. Notwithstanding the limitations of the method this result suggests that in the pulmonary vascular bed the resistance on the arterial side and that on the venous side of the effective midpoint of capillaries are similar.

Psoriasis and metabolic syndrome: comorbidity mechanisms

2019 ◽  
Vol 1 (7) ◽  
pp. 34-38
Author(s):  
E. V. Dontsova ◽  
O. Yu. Olisova ◽  
L. S. Kruglova
Keyword(s):  
Metabolic Syndrome ◽  
Negative Correlation ◽  
Inflammatory Cytokine ◽  
Antioxidant Ability ◽  
Weak Correlation ◽  
Strong Negative Correlation ◽  
The Metabolic Syndrome ◽  
Diagnostic Signs ◽  
Weak Negative Correlation ◽  
Correlation Link

Objectives: to study communications of separate components of the metabolic syndrome (MS) and immune and oxidative characteristics of patients with psoriasis in combination with MS. Methods. The research included 312 patients with psoriasis having diagnostic signs of a metabolic syndrome. Biochemical and immunological researches were conducted by means of immunofermental and immunokhemilyuminestsentny analyses. Results. At patients with psoriasis at a combination to MS abdominal obesity, a giperleptinemiya, insulin resistance, high oxidizing potential and hyperactivity of interleukins (ILS) -1β,-6,-8, a factor of a necrosis of tumors an alpha (FNO-α), interferon scale (INF-γ) are noted. the waist circle’ is characteristic direct weak correlation with the pro-inflammatory tsitokina oxidized by lipoproteins of blood (LDL-ok) and with the general oxidizing ability of blood (OOS), weak negative correlation of an indicator - with the general antioxidant ability of blood (OAS) and superoxide dismutase (SOD). The HOMA-IR index has direct correlation link of moderate force with levels of a leptin of blood, LDL-ok, OOS, pro-inflammatory tsitokin, negative correlation of moderate force - with OAS, SOD. At patients with psoriasis with MS direct strong correlation link of level of a leptin of blood with activity of the studied pro-inflammatory cytokine, LDL-ok, OOS moderated is established with the level of insulin in the blood., the HOMA-IR index, strong negative correlation with OAS, SOD. Conclusion. Presence at patients with psoriasis of signs of a metabolic syndrome is followed by increase in activity of immune and inflammatory mechanisms, development of oxidative stress.

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