Screening of resonant magnetic perturbation fields assuming various plasma flow models

SummaryAn accurate catheter-free technique for clinical determination simultaneouslyof glomerular filtration rate and effective renal plasma flow by means of radioisotopes has been developed. The renal function is estimated by the amount of radioisotopes necessary to maintain a constant concentration in the patient’s blood. The infusion pumps are steered by a feedback system, the pumps being automatically turned on when the radiation measured over the patient’s head falls below a certain preset level and turned off when this level is again readied. 131I-iodopyracet was used for the estimation of effective renal plasma flow and125I-iothalamate estimation of the glomerular filtration rate. These clearances were compared to the conventional bladder clearances and good correlation was found between these two clearance methods (correlation coefficients 0.97 and.90 respectively). The advantages and disadvantages of this new clearance technique are discussed.

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RENAL FUNCTION AND KIDNEY SIZE FOLLOWING HYPOPHYSECTOMY IN MAN

Acta Endocrinologica ◽

10.1530/acta.0.0480348 ◽

1965 ◽

Vol 48 (3) ◽

pp. 348-354 ◽

Cited By ~ 33

Author(s):

Thomas Falkheden ◽

Ingmar Wickbom

Keyword(s):

Renal Function ◽

Diabetic Retinopathy ◽

Glomerular Filtration Rate ◽

Plasma Flow ◽

Mammary Carcinoma ◽

Filtration Rate ◽

Renal Plasma Flow ◽

Kidney Weight ◽

Kidney Size ◽

Before And After

ABSTRACT Measurements of glomerular filtration rate (GFR) and renal plasma flow (RPF) were performed in close connection with roentgenographic estimation of kidney size, before and after hypophysectomy, in 10 patients (four cases of metastatic mammary carcinoma, five cases of diabetic retinopathy and one case of acromegaly). Hypophysectomy was regularly followed by a decrease in GFR and RPF. In most cases, a reduction in the roentgenographic kidney size was also observed. However, the changes in the roentgenographic kidney size and calculated kidney weight after hypophysectomy were smaller and occurred at a slower rate than the alterations in GFR and RPF. The results favour the view that, primarily, the decrease in GFR and RPF following hypophysectomy is essentially functional rather than due to a reduced kidney mass.

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Avalanche Stratification - Experimental Tests of the “Metastable Wedge” and “Continuous Flow” Models

MRS Proceedings ◽

10.1557/proc-627-bb2.6 ◽

2000 ◽

Vol 627 ◽

Author(s):

M. E. Swanson ◽

M. Landreman ◽

J. Michel ◽

J. Kakalios

Keyword(s):

Continuous Flow ◽

Granular Media ◽

Experimental Tests ◽

Coarse Sand ◽

Angle Of Repose ◽

Flow Models ◽

Maximum Angle ◽

Stratification Effect ◽

Upward Moving ◽

Moving Layer

ABSTRACTWhen an initially homogeneous binary mixture of granular media such as fine and coarse sand is poured near the closed edge of a “quasi-two-dimensional” Hele-Shaw cell consisting of two vertical transparent plates held a narrow distance apart, the mixture spontaneously forms alternating segregated layers. Experimental measurements of this stratification effect are reported in order to determine which model, one which suggests that segregation only occurs when the granular material contained within a metastable heap between the critical and maximum angle of repose avalanches down the free surface, or one for which the segregation results from smaller particles becoming trapped in the top surface and being removed from the moving layer during continuous flow. The result reported here indicate that the Metastable Wedge model provides a natural explanation for the initial mixed zone which precedes the formation of the layers, while the Continuous Flow model explains the observed upward moving kink of segregated material for higher granular flux rates, and that both mechansims are necessary in order to understand the observed pairing of segregated layersfor intermediate flow rates and cell separations.

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