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A V Gordeev

Publications and source records attributed to A V Gordeev.

At least 19 recordsLinked to original sources
PubMed2006

Depolarization of decaying counterflow turbulence in He II.

We present experimental evidence backed up by numerical simulations that the steady-state vortex tangle created in He II by heat-transfer counterflow is strongly polarized. When the heater that generates the counterflow turbulence is switched off, the vortex tangle decays, the vortex lines randomize their spatial orientation and the tangle's polarization decreases. The process of depolarization slows down the recovery of the transverse second sound signal which measures the vortex line density; at some values of parameters it even leads to a net decrease of the amplitude of the transverse second sound prior to reaching the universal -32 power temporal law decay typical of classical homogeneous isotropic turbulence in a finite-sized channel.

Journal Article↗
PubMed2003

Decay of counterflow He II turbulence in a finite channel: possibility of missing links between classical and quantum turbulence.

Decay of He II counterflow turbulence generated by applying a heat pulse to the closed end of a circular channel is investigated using second sound attenuation. Several orders of magnitude of decaying vortex line density display various regimes, starting with the inverse time decay predicted by Vinen towards distinct classical t(-3/2) power law occurring after saturation of the energy containing length scale by the size of the channel. The decaying counterflow turbulence displays a surprisingly close resemblance to recently reported decaying grid turbulence in He II, and both of them appear closely linked to classical grid generated turbulence.

Journal Article↗
PubMed2001

[Heterogeneity of causes of proteinuria in patients with non-insulin dependent diabetes mellitus].

AIM: To make a retrospective clinicomorphological (autopsy) study of proteinuria causes. MATERIAL AND METHODS: The records have been analysed for 231 patients with non-insulin-dependent diabetes mellitus (NIDDM) over 60 years of age who died in a general hospital between 1990 and 1999. The choice of patients with diabetic nephropathy (DN) for a further morphological investigation was based on the presence of proteinuria (> 0.5 g/day), normal renal function. 72 patients met the above criteria. Of them 26 were women. RESULTS: Proteinuria occurred more frequently in men (63.4%). A morphological examination of the kidneys revealed diabetic glomerulosclerosis (diffuse and focal) in 48(67%) patients. In 24(33%) patients proteinuria resulted from non-diabetic affection of the kidneys: amyloidosis, atherosclerotic and/or hypertensive nephroangiosclerosis, membraneous and myelomic nephropathy, mesangioproliferative glomerulonephritis. Glomerular changes were not registered in 4 patients. 35(72%) DN patients had diabetic retinopathy which was not found in patients with non-diabetic renal affection. CONCLUSION: Diabetic retinopathy in patients with NIDDM and proteinuria allows to conclude that the latter is consequent to DN. The absence of diabetic retinopathy in such patients promotes a search for other causes of proteinuria.

Age Factors↗
PubMed1998

[Renal lesions in elderly patients with diabetes mellitus].

AIM: To elucidate the role of some renal diseases, pyelonephritis in particular, in elderly patients with type 2 diabetes mellitus (DM). MATERIALS AND METHODS: The trial included 150 patients with diabetes mellitus type 2 aged over 60 years with DM duration 16.6 +/- 7.8 years. All the patients underwent general clinical examination, Reberg-Tareev test, urine seeding, renal ultrasonography. RESULTS: The diagnoses associated with renal pathology were made in 75% of patients, the specific renal parenchymal damage (diabetic nephropathy-DN) proper was much less common (73 patients with type 2 DM). 16 of them were found to have chronic renal failure. The concurrent abnormalities included pyelonephritis (21%), urolithiasis (14%), renal cysts (19%), their combination (43%). Concomitant pyelonephritis had the most significant impact on renal function. Essential hypertension occurred in 65% of patients. CONCLUSION: In old age, renal damage specific for DM develops in the presence of pyelonephritis, cystic degeneration of the parenchyma, involutional processes, atherosclerotic and hypertensive arteriolosclerosis.

Aged↗
PubMed1991

[Senile pyelonephritis with the arterial hypertension syndrome: the use of trental].

Eighteen patients with senile pyelonephritis and nephrogenic arterial hypertension were examined for the effect of trental monotherapy (600 mg/day) on intrarenal hemodynamics, the rate of glomerular filtration (effective renal blood flow, the intensity of blood flow in the medullary layer of the kidney), activity of the renin-angiotensin-aldosterone system (plasma renin activity, plasma and urine aldosterone), prostaglandin synthetic capacity of the kidneys (PGE and PGF2 alpha), water-electrolyte balance (circulating blood volume, sodium content in the serum and its excretion with urine), and on arterial pressure and general vascular peripheral resistance. Prolonged administration of the drug (from 3 weeks to 6 months) led to a significant improvement of the medullary blood flow, increase (p less than or equal to 0.05) of excretion of natriuretic PGE [correction of RGE] and lowering (p less than or equal to 0.05) of diurnal excretion of PGF2 alpha, which was accompanied by a rise of natriuresis (p less than or equal to 0.05) and diuresis.

Dinoprost↗
PubMed1990

[Arterial hypertension in senile pyelonephritis: the renal hemodynamics].

Eighteen patients aged 60 to 80 years suffering from chronic pyelonephritis (CPN) and nephrogenous arterial hypertension (AH) were examined for intrarenal hemodynamics: effective renal blood flow (ERBF), glomerular filtration rate (GFR), filtration fraction (FF), renal vascular resistance (R). Renal hemodynamics in patients with senile pyelonephritis and AH was found to be characterized by a decrease of ERBF, GFR, FF, an increase of R (p less than 0.01), with the alterations being related to the AH intensity, mass of the functioning renal parenchyma (for GFR) and partly (for R) to the pyelonephritis and AH standing. R which is dependent on the duration and course (number of exacerbations) of CPN is one of the factors that determine the development and gravity of AH in senile pyelonephritis.

Aged↗
PubMed1990

[The determination of the separate intrarenal hemodynamics and its place in the diagnosis of nephrogenic arterial hypertension].

Differential diagnosis between essential hypertension and secondary arterial hypertension (AH) that developed in the presence of chronic pyelonephritis was made in 12 patients with AH and the urinary syndrome (leukocyturia and bacteriuria). With that purpose in view for revealing functional renal asymmetry, a study was made of the effective renal plasma flow (ERPF) and glomerular filtration rate (GFR) in each kidney separately based on computation of 99Tc-DTPA and 131I-hippuran clearances. Some patients in whom AH was later regarded as essential manifested practically equal values of the ERPF and GFR from both sides, with the real characteristics of the latter ones being little different from the respective populational values calculated by computer bearing in mind the body surface of those patients. The other patients' group showed, along with a decrease of the total ERPF and GFR, a dramatic asymmetry of the intrarenal hemodynamics of both ERPF and GFR, which is fairly characteristic of chronic pyelonephritis. This allows the syndrome of AH to be regarded in those patients as secondary.

Aged↗