ABSTRACT
Eleven fresh ex vivo porcine kidneys were perfused in the artery, vein and ureter with degassed Dulbecco׳s Modified Eagle Medium (DMEM). The effect of perfusion pressure was evaluated using ten different pressures combinations. The shear modulus of the tissues was estimated during perfusion using shear wave elastography. The organ weight change was measured by a digital scale and cameras were used to follow the changes of the dimensions after each pressure combination. The effect of perfusion on the weight and the thickness was non-reversible, whereas the effect on the shear modulus was reversible. Pressure was found to increase the average shear modulus in the cortex by as much as 73%. A pressure of 80 mmHg was needed to observe tissues shear modulus in the same range as in vivo tests (Gcortex=9.1 kPa, Gmedulla=8.5 kPa ex vivo versus Gcortex=9.1 kPa, Gmedulla=8.7 kPa in vivo in Gennisson et al., 2012).
Subject(s)
Elastic Modulus/physiology , Kidney/anatomy & histology , Kidney/physiology , Pressure/adverse effects , Shear Strength/physiology , Animals , Biomechanical Phenomena/physiology , Elasticity Imaging Techniques , Kidney/blood supply , Models, Animal , Organ Size/physiology , Perfusion/methods , Stress, Mechanical , SwineSubject(s)
Abdominal Injuries/diagnostic imaging , Abdominal Injuries/physiopathology , Multiple Trauma/diagnostic imaging , Multiple Trauma/physiopathology , Wounds, Nonpenetrating/diagnostic imaging , Wounds, Nonpenetrating/physiopathology , Abdomen , Aged, 80 and over , Cadaver , Elasticity , Humans , Motion , Pattern Recognition, Automated , Stress, Mechanical , UltrasonographyABSTRACT
Voyager 2 images of Neptune reveal a windy planet characterized by bright clouds of methane ice suspended in an exceptionally clear atmosphere above a lower deck of hydrogen sulfide or ammonia ices. Neptune's atmosphere is dominated by a large anticyclonic storm system that has been named the Great Dark Spot (GDS). About the same size as Earth in extent, the GDS bears both many similarities and some differences to the Great Red Spot of Jupiter. Neptune's zonal wind profile is remarkably similar to that of Uranus. Neptune has three major rings at radii of 42,000, 53,000, and 63,000 kilometers. The outer ring contains three higher density arc-like segments that were apparently responsible for most of the ground-based occultation events observed during the current decade. Like the rings of Uranus, the Neptune rings are composed of very dark material; unlike that of Uranus, the Neptune system is very dusty. Six new regular satellites were found, with dark surfaces and radii ranging from 200 to 25 kilometers. All lie inside the orbit of Triton and the inner four are located within the ring system. Triton is seen to be a differentiated body, with a radius of 1350 kilometers and a density of 2.1 grams per cubic centimeter; it exhibits clear evidence of early episodes of surface melting. A now rigid crust of what is probably water ice is overlain with a brilliant coating of nitrogen frost, slightly darkened and reddened with organic polymer material. Streaks of organic polymer suggest seasonal winds strong enough to move particles of micrometer size or larger, once they become airborne. At least two active plumes were seen, carrying dark material 8 kilometers above the surface before being transported downstream by high level winds. The plumes may be driven by solar heating and the subsequent violent vaporization of subsurface nitrogen.
