Effect of Na adsorption on the structural and electronic properties of Si(111)√3 × âˆš3-Au surface.

Adsorption of ∼0.1 ML of Na onto the Si(111)√3 × âˆš3-Au surface held at 300 °C has been found to induce pronounced changes in its structural and electronic properties. Domain wall networks, characteristic of the pristine surface, are removed completely, leading to the formation of a highly ordered homogeneous surface. The original atomic arrangement of the Si(111)√3 × âˆš3-Au is preserved and Na atoms occupy T4 adsorption sites at the centers of surface Si trimers. Upon Na adsorption, a pronounced metallic S1 surface-state band develops. It is characterized by a large spin splitting (momentum splitting at the Fermi level Δk∥ = 0.027 Å(-1) and consequent energy splitting ΔEF = 110 meV), large electron filling (on the order of 0.5 electrons per √3 × âˆš3 unit cell) and small effective electron mass of (0.028 ± 0.006)me. The natural consequence of the latter properties is a high surface conductivity of the Si(111)√3 × âˆš3-(Au, Na) surface.

[Transurethral plasmokinetic resection and vaporization is a new method of treatment of prostatic adenoma].

Clinical efficacy and safety ofplasmakinetic resection and vaporization were studied in 28 patients with prostatic adenoma (mean age 68 years, mean size of the prostate 65 cm3). Complaints by IPSS scale, quality of life index, results of uroflowmetry and prostatic ultrasonography were assessed before surgery (transurethral plasmakinetic resection and prostatic vaporization) and 1, 3, 6 and 12 months after it. Twenty-five and 15 patients after 6 and 12 months after the operation were examined with the following results: IPSS was 6 scores, on the average (22.5 scores before the operation), quality of life index--3.1 (5.3 scores). Qmax was in 3 months 20 ml/s, on the average (7.5 ml/s), residual urine was under 35 ml (130.7 ml). Pilot results point to high clinical efficacy and safety of plasmakinetic resection and vaporization in patients with prostatic adenoma. Therefore, further studies of the method and accumulation of clinical experience are necessary.

[Postoperative urological complications of transurethral electrosurgical interventions on the prostate for adenoma].

The aim of the study was comparison of urological complications after transurethral resection and its low-invasive alternatives: vaporization, rotoresection, vaporization resection, prostatic incision. Case histories were studied of 5401 patients operated endoscopically for prostatic adenoma in 1991-2003. Standard TUR was made in 5003 patients, incision--in 112, vaporization--in 119, vaporizing resection--in 107, rotoresection--in 60 patients. Of early complications after TUR hemorrhage was the most dangerous, hemotransfusion was made in 3.9% cases. No hemorrhagic complications occurred in rotoresection, no hemotransfusions were made in vaporization and vaporizing resection, prostatic incision was complicated by hemorrhage only in 0.9% cases. By infection complications rate (0.9-7.5%), the differences were not significant. Of late complications, sclerosis of the urinary bladder cervis was most frequent (10.7-11.2%) after rotoresection and vaporizing resection, urethral stricture--after TUR (6.9%). By number of complications, incision was least invasive. Thus, basic problem after TUR is hemorrhage. Low-invasive alternative methods resolve this problem. But they have limitations. The best way out is improvement of intraoperative hemostasis during TUR.