Lattice dynamics of ß-V2O5: Raman spectroscopic insight into the atomistic structure of a high-pressure vanadium pentoxide polymorph.

We report here the Raman spectrum and lattice dynamics study of a well-crystallized ß-V(2)O(5) material prepared via a high-temperature/high-pressure (HT/HP) route, using α-V(2)O(5) as the precursor. Periodic quantum-chemical density functional theory calculations show good agreement with the experimental results and allow one to assign the observed spectral features to specific vibrational modes in the ß-V(2)O(5) polymorph. Key structure-spectrum relationships are extracted from comparative analysis of the vibrational states of the ß-V(2)O(5) and α-V(2)O(5) structures, and spectral patterns specific to the basic units of the two V(2)O(5) phases are proposed for the first time. Such results open the way for the use of Raman spectroscopy for the structural characterization of vanadium oxide-based host lattices of interest in the field of lithium batteries and help us to greatly understand the atomistic mechanism involved in the α-to-ß phase transition of vanadium pentoxide.

Formation of dissolved gaseous mercury in a tropical lake (Petit-Saut reservoir, French Guiana).

Formation of dissolved gaseous mercury (DGM) and its volatilization from aquatic systems can be considered as a natural attenuation process, which limits the methylation of mercury (Hg) and Hg accumulation in fish. Although gold-mining activity and erosion of tropical soils lead to increased Hg concentration in aquatic systems, little is known about DGM production and distribution in tropical aqueous systems. Our work explores the vertical distribution and principal sources of DGM in a meromictic Amazonian reservoir. Dissolved gaseous mercury measurements carried out in Petit-Saut reservoir (French Guiana, South America) revealed DGM increase in the surface waters and at the bottom layers of the reservoir during the dry season. As in arctic and temperate lakes, high DGM concentrations in surface waters were attributed to sunlight-mediated photochemical processes. Dissolved gaseous mercury concentrations in the anaerobic hypolimnion were larger than in temperate or arctic lakes. In order to elucidate Hg(II) reduction pathways in the bottom layer of tropical reservoir, laboratory Hg(II) reduction experiments were performed with anoxic aqueous suspensions of surface sediments either untreated or treated by gamma-ray and NaN3. Our results indicated that DGM production at the bottom layer of Petit-Saut reservoir was biologically mediated. Dissolved gaseous mercury formation rates in the surface sediment suspensions were of the same order of magnitude as formation rates in freshwater lakes reported in literature.

[Vesicoureteral reflux in renal transplantation].

Frequency of vesicoureteral reflux (VUR) variants was studied with miction cystography in 40 patients with chronic renal insufficiency. In 8 (20%) patients VUR was in their kidneys. The kidney was transplanted in 30 patients. The rate of urological complications was compared in ureterocystostomy by our technique and other procedures. In patients operated by our technique VUR did not occur. In 3 of 10 patients operated by other methods VUR into the transplant was found. Own kidney on the side of the reflux was removed in 4 patients after kidney transplantation. Indication for removal of own kidneys after allotransplantation of the kidney is urinary infection, arterial hypertension, pain in the lumbar spine. The proposed technique of ureterocystostomy has advantages in prevention of VUR into the renal transplant.

[Peritoneal dialysis in the treatment of chronic renal failure]. / Primenenie peritoneal'nogo dializa v lechenii KHPN.

Fifty-four patients were treated with peritoneal dialysis for terminal chronic renal failure. Clinical-laboratory indices were assessed in patients on chronic peritoneal dialysis. Advantages of continuous ambulatory peritoneal dialysis over hemodialysis are analysed in terms of social rehabilitation of the patients. Complications of chronic peritoneal dialysis as a method and algorithms of their treatment are outlined. The role of peritoneal dialysis as a preparatory stage before transplantation of the kidney is assessed.

[Advantages of epidural anesthesia in patients with end-stage chronic renal failure]. / Preimushchestva primeneniia épidural'noi anestezii u bol'nykh s terminal'noi khronicheskoi pochechnoi nedostatochnost'iu.

The authors analyze the experience gained in anesthesiological management of 667 surgeries in patients with the end-stage chronic renal failure. 206 patients were operated on under epidural anesthesia and 461 under general anesthesia. The technique of anesthesia, preparation of patients, and the management during and after surgery are described. 63 hemodialysis procedures were performed for 4 h before and 154 for 12 h after surgery. The complications occurring during and after anesthesia by both methods are analyzed. Epidural anesthesia was found to be more safe for patients with the end-stage chronic renal failure. General anesthesia more often led to hemodynamic, respiratory, metabolic disorders, and other hemostasis disturbances.

[Use of plasmapheresis in intensive therapy of acute steroid-resistant rejection reaction in renal transplants]. / Primenenie plazmafereza v intensivnoi terapii ostroi steroidrezistentnoi reaktsii ottorzheniia renal'nykh transplantatov.

For many years the treatment of steroid-resistant rejection (SSR) remains a common problem od renal transplantation. We used plasmapheresis (PPH) in the treatment of SRR in 29 renal transplant recipients. All patients had progressive deterioration of renal function and compatible biopsy histology. The first group (15 patients) was administered PPH with methylprednisolone (MP). The second group (14 patients) was treated by intravenous MP. There was no significant difference in the time of beginning and severity of rejection. In the PPH group the results were better: a significant increase in SSR reversion was attained (73.3%) in comparison with the control (42.8%), the number of grafts lost during the first year was less (26.7 versus 57.2%). Better results were observed in patients with high levels of serum anti-HLA antibodies. Their transplants functioned well during 12 months after SSR. Hence, PPH can be used in patients with SSR with high levels of anti-HLA antibodies.

[A comparative evaluation of the use of pyeloureterostomy and ureterocystostomy in treating the urological complications following kidney transplantation]. / Sravnitel'na otsenka primeneniia pieloureterostomii i ureterotsistostomii pri lechenii urologicheskikh oslozhnenii posle transplantatsii pochki.

Ureteral stricture and necrosis after allotransplantation of the cadaver kidney were corrected in 14 and 7 patients, respectively. 12 patients have undergone ureterocystostomy, 9 patients--pyeloureterostomy with the recipient's ureter. Shortly after ureterocystostomy anastomosis insufficiency developed in 7 out of 12 patients, after pyeloureterostomy in 1 of 9 patients (p < 0.05). Secondary complications led to the transplants' rejection in 5 of 12 and 1 of 9 patients, respectively (p < 0.05). 2 patients died due to septic complications after ureterocystostomy. Long after surgery stricture in anastomosis and distal ureter occurred in 3 recipients after ureterocystostomy; after pyeloureterostomy (6 months and 2 years) nephrectomy was conducted in 2 cases because of clinical manifestations of pyelonephritis. It is inferred that pyeloureterostomy with the recipient's ureter is preferable to ureterocystostomy in the treatment of ureteral necrosis and stricture following transplantation of the kidney.

[A familial form of nephrolithiasis in patients following kidney transplantation?]. / Semeinaia forma nefrolitiaza u bol'nykh posle transplantatsii pochki?

Causes and mechanisms underlying nephrolithiasis after transplantation of the kidney differ much from known in other urological patients. We have found calculi in transplanted kidney in 5 of 939 surgical patients. Two cases of concrement formation in the transplant in the members of the same family aged 22 and 26 years we report as interesting. Our experience and literature data suggested family nature of the concrements. One of the patients underwent pyelolithotomy, the other impulse lithotripsy. Both the transplants function normally 5 years after kidney transplantation.