Role of equilibrium plasma flow on damping of slow MHD waves

Abstract. The role of intense high-altitude electric field (E-field) peaks for large-scale plasma convection is investigated with the help of Cluster E-field, B-field and density data. The study covers 32 E-field events between 4 and 7 RE geocentric distance, with E-field magnitudes in the range 500–1000 mV/m when mapped to ionospheric altitude. We focus on E-field structures above the ionosphere that are typically coupled to discrete auroral arcs and their return current region. Connected to such E-field peaks are rapid plasma flows directed along the discrete arcs in opposite directions on each side of the arc. Nearly all the E-field events occur during active times. A strong dependence on different substorm phases is found: a majority of intense E-field events appearing during substorm expansion or maximum phase are located on the nightside oval, while most recovery events occur on the dusk-to-dayside part of the oval. For most expansion and maximum phase cases, the average background plasma flow is in the sunward direction. For a majority of recovery events, the flow is in the anti-sunward direction. The net plasma flux connected to a strong E-field peak is in two thirds of the cases in the same direction as the background plasma flow. However, in only one third of the cases the strong flux caused by an E-field peak makes an important contribution to the plasma transport within the boundary plasma sheet. For a majority of events, the area covered by rapid plasma flows above discrete arcs is too small to have an effect on the global convection. This questions the role of discrete auroral arcs as major driver of plasma convection.

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Water metabolism after cisplatin in the rat

AJP Renal Physiology ◽

10.1152/ajprenal.1982.243.1.f36 ◽

1982 ◽

Vol 243 (1) ◽

pp. F36-F43 ◽

Cited By ~ 3

Author(s):

J. A. Gordon ◽

L. N. Peterson ◽

R. J. Anderson

Keyword(s):

Renal Failure ◽

Acute Renal Failure ◽

Water Intake ◽

Plasma Flow ◽

Water Metabolism ◽

Water Load ◽

Interstitial Solute ◽

Plasma Vasopressin ◽

And Control

A polyuric state is often observed after cis-dichlorodiammine platinum (cisplatin). To study the mechanism of this polyuria we gave 5-6 mg/kg cisplatin to conscious rats and observed polydipsia and a polyuric form of mild acute renal failure. A defect in renal concentrating ability was observed 1 and 8 days after cisplatin. Animals demonstrated diminished postdehydration plasma vasopressin at 1 but not at 8 days after cisplatin, and exogenous vasopressin corrected the renal concentration defect at 1 but not at 8 days after cisplatin. To assess the role of polydipsia in the concentration defect, water intake in cisplatin-treated animals was matched to pair-fed controls. Prevention of polydipsia improved the polyuria but not the concentration defect seen 8 days after cisplatin. To assess intrarenal factors in the renal concentration defect, postdehydration interstitial solute was measured and was significantly lower in cisplatin-treated than in control animals. To determine whether the diminished interstitial solute was due to vascular mechanisms, inner medullary plasma flow was measured and was identical in cisplatin-treated and control rats. Treatment with cisplatin also resulted in decreased excretion of a water load. We conclude that either impaired synthesis or release of vasopressin is the cause of the impaired renal concentration seen 1 day after cisplatin. Eight days after cisplatin, the renal concentration defect is due in part to decreased interstitial tonicity.

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Role of perovskite-type metal oxides on atmospheric pressure non-equilibrium plasma generation

Thin Solid Films ◽

10.1016/s0040-6090(00)01666-7 ◽

2001 ◽

Vol 386 (2) ◽

pp. 147-151 ◽

Cited By ~ 4

Author(s):

Kazutoshi Kiyokawa ◽

Kazuo Sugiyama ◽

Manabu Tomimatsu ◽

Hideki Kurokawa ◽

Hiroshi Miura

Keyword(s):

Metal Oxides ◽

Atmospheric Pressure ◽

Equilibrium Plasma ◽

Plasma Generation ◽

Perovskite Type ◽

Non Equilibrium

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The role of photo-ionization and residual electrons in atmospheric pressure non-equilibrium plasma jets

2015 IEEE International Conference on Plasma Sciences (ICOPS) ◽

10.1109/plasma.2015.7179518 ◽

2015 ◽

Author(s):

S. Wu ◽

X. Lu

Keyword(s):

Atmospheric Pressure ◽

Plasma Jets ◽

Equilibrium Plasma ◽

Photo Ionization ◽

Non Equilibrium

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Plasma Waves in the Inner Magnetosphere

10.1007/978-3-030-82167-8_4 ◽

2021 ◽

pp. 85-119

Author(s):

Hannu E. J. Koskinen ◽

Emilia K. J. Kilpua

Keyword(s):

Radiation Belt ◽

Low Frequency ◽

Plasma Waves ◽

Mhd Waves ◽

Particle Interactions ◽

Inner Magnetosphere ◽

Very Low Frequency ◽

Link Type ◽

Wave Modes

AbstractUnderstanding the role of plasma waves, extending from magnetohydrodynamic (MHD) waves at ultra-low-frequency (ULF) oscillations in the millihertz range to very-low-frequency (VLF) whistler-mode emissions at frequencies of a few kHz, is necessary in studies of sources and losses of radiation belt particles. In order to make this theoretically heavy part of the book accessible to a reader, who is not familiar with wave–particle interactions, we have divided the treatise into three chapters. In the present chapter we introduce the most important wave modes that are critical to the dynamics of radiation belts. The drivers of these waves are discussed in Chap. 10.1007/978-3-030-82167-8_5 and the roles of the wave modes as sources and losses of radiation belt particles are dealt with in Chap. 10.1007/978-3-030-82167-8_6.

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Renal Cortical Vasoconstriction Contributes to Development of Salt-Sensitive Hypertension after Angiotensin II Exposure

Journal of the American Society of Nephrology ◽

10.1681/asn.v12112263 ◽

2001 ◽

Vol 12 (11) ◽

pp. 2263-2271

Author(s):

MARTHA FRANCO ◽

EDILIA TAPIA ◽

JOSÉ SANTAMARÍA ◽

IGNACIO ZAFRA ◽

ROMEO GARCÍA-TORRES ◽

...

Keyword(s):

Angiotensin Ii ◽

Plasma Flow ◽

Critical Role ◽

Progressive Increase ◽

Tubulointerstitial Injury ◽

High Salt Diet ◽

Single Nephron ◽

Glomerular Hemodynamics ◽

Salt Sensitive Hypertension

Abstract. Rats that are administered angiotensin II (AngII) for 2 wk develop persistent salt-sensitive hypertension, which can be prevented by the immunosuppressor mycophenolate mofetil (MMF) given during the AngII infusion. This study examined the contribution of glomerular hemodynamics (GFR dynamics) in the post-AngII hypertensive response to a high-salt diet (HSD) and the effect of MMF treatment. During AngII administration, rats developed severe hypertension (systolic BP [SBP], 185 ± 3.9 mmHg), proteinuria, afferent and efferent vasoconstriction, and glomerular hypertension. Rats that received AngII+MMF showed similar responses to AngII; however, they developed lower proteinuria (P < 0.05). At 2 wk, AngII was withdrawn and SBP returned toward normal. Rats were then placed on an HSD (4% NaCl), resulting in a progressive increase in SBP (155 ± 8.2 mmHg at week 1 and 163 ± 4.5 mmHg at week 5). GFR dynamic alterations persisted after AngII was stopped, i.e., afferent and efferent vasoconstriction, decreased glomerular plasma flow and single-nephron GFR, and lower ultrafiltration coefficient. These changes correlated with the thickening of the afferent arteriole and with focal tubulointerstitial injury. In the AngII+MMF group, SBP remained unchanged throughout the HSD period (146 ± 2.3 mmHg at week 1 and 148 ± 4.4 mmHg at week 5) in association with less afferent arteriolar thickening and tubulointerstitial injury. Single-nephron GFR, glomerular plasma flow, efferent resistance, and ultrafiltration coefficient returned to normal with a significant reduction in afferent resistance. These results suggest a critical role of cortical vasoconstriction in salt-sensitive hypertension. The MMF-induced prevention of these changes suggests that immune mechanisms are involved in the vasoconstrictive response.

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Nitric oxide: a potential mediator of amino acid-induced renal hyperemia and hyperfiltration.

Journal of the American Society of Nephrology ◽

10.1681/asn.v1121271 ◽

1991 ◽

Vol 1 (12) ◽

pp. 1271-1277

Author(s):

A J King ◽

J L Troy ◽

S Anderson ◽

J R Neuringer ◽

M Gunning ◽

...

Keyword(s):

Nitric Oxide ◽

Glomerular Filtration Rate ◽

Amino Acid ◽

Glomerular Filtration ◽

Plasma Flow ◽

Filtration Rate ◽

Renal Plasma Flow ◽

Competitive Inhibitor ◽

Arterial Blood

The role of nitric oxide in the modulation of systemic and renal hemodynamics was examined by using N omega-monomethyl-L-arginine (L-NMMA, 110 micrograms/kg/min), a competitive inhibitor of the conversion of L-arginine to nitric oxide. L-NMMA or saline vehicle (9.6 microL/min) was infused intravenously into anesthetized euvolemic Munich-Wistar rats. After 30 min, L-NMMA resulted in a uniform increase in mean arterial blood pressure (111 +/- 1 to 128 +/- 2 mmHg; P less than 0.05) and a modest reduction in renal plasma flow rate (4.4 +/- 0.2 to 4.2 +/- 0.1 mL/min; P less than 0.05), without change in glomerular filtration rate (1.16 +/- 0.03 to 1.15 +/- 0.03 mL/min); vehicle had no effect on these renal parameters. These rats were then subdivided to receive an intravenous infusion (37 microL/min) of either 10% glycine, 11.4% mixed amino acids, or equiosmolar dextrose. L-NMMA pretreatment markedly attenuated glycine-induced hyperfiltration (10 +/- 6 versus 33 +/- 5%, L-NMMA versus vehicle; P less than 0.05) and obliterated the renal hyperemic response (-7 +/- 6 versus 16 +/- 4%, L-NMMA versus vehicle; P less than 0.05). L-NMMA also caused modest blunting of the mixed amino acid-induced hyperfiltration (18 +/- 4 versus 30 +/- 4%, L-NMMA versus vehicle; P = 0.056) but failed to curtail the renal hyperemia (16 +/- 6 versus 20 +/- 4%). Dextrose had no effect on glomerular filtration rate or renal plasma flow.(ABSTRACT TRUNCATED AT 250 WORDS)

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Role of deep nephrons and the terminal collecting duct in a mannitol-induced diuresis

AJP Renal Physiology ◽

10.1152/ajprenal.1981.240.5.f411 ◽

1981 ◽

Vol 240 (5) ◽

pp. F411-F422 ◽

Cited By ~ 4

Author(s):

J. Buerkert ◽

D. Martin ◽

J. Prasad ◽

D. Trigg

Keyword(s):

Plasma Flow ◽

Collecting Duct ◽

Renal Plasma Flow ◽

Distal Tubule ◽

Sodium Reabsorption ◽

Water Reabsorption ◽

Single Nephron ◽

Papillary Collecting Duct ◽

Reduced Water

Recollection micropuncture in Munich-Wistar rats was used to study the effects of intravenous hypertonic mannitol infusions on fluid reabsorption by surface nephrons, prior to the bend of Henle's loop of deep nephrons, and along the papillary collecting duct. During mannitol diuresis, single nephron glomerular filtration rate rose significantly in surface nephrons but fell in deep nephrons. Although mannitol increased the delivery of sodium and water to the end of the proximal tubule and to the first portion of the distal tubule of surface nephrons, water and sodium were reabsorbed between these two sites. In deep nephrons, water reabsorption prior to the bend of the loop of Henle was significantly decreased. Absolute sodium delivery to this site was reduced despite a marked decrease in fractional sodium reabsorption prior to the bend. Papillary osmolality was decreased. Renal plasma flow and inner medullary plasma flow (IMPF) increased proportionally. The reduced water extraction prior to the bend of deep nephrons and the decrease in papillary osmolality could have been partly due to a concomitant increase in IMPF and a decrease in sodium delivery to the medulla. The reabsorption of delivered sodium and water by the papillary collecting duct was reduced to a greater extent than could be expected from the increase in sodium delivery.

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