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We present a powerful kinetic Monte Carlo (KMC) algorithm that allows one to simulate the growth of nanocrystalline silicon by plasma enhanced chemical vapor deposition (PECVD) for film thicknesses as large as several hundreds of monolayers. Our method combines a standard n-fold KMC algorithm with an efficient Markovian random walk scheme accounting for the surface diffusive processes of the species involved in PECVD. These processes are extremely fast compared to chemical reactions, thus in a brute application of the KMC method more than 99% of the computational time is spent in monitoring them. Our method decouples the treatment of these events from the rest of the reactions in a systematic way, thereby dramatically increasing the efficiency of the corresponding KMC algorithm. It is also making use of a very rich kinetic model which includes 5 species (H, SiH3, SiH2, SiH, and Si2H5) that participate in 29 reactions. We have applied the new method in simulations of silicon growth under several conditions (in particular, silane fraction in the gas mixture), including those usually realized in actual PECVD technologies. This has allowed us to directly compare against available experimental data for the growth rate, the mesoscale morphology, and the chemical composition of the deposited film as a function of dilution ratio. [ABSTRACT FROM AUTHOR]

In a previous paper, we investigated the role of inherent structures in the vitrification process of glass-forming materials, showing that the dynamical transitions between inherent structures (states) can be well predicted by a first-order kinetic scheme based on infrequent-event theory at low temperatures. In this work, we utilize and extend that methodology in order to completely reconstruct the system dynamics in the form of the mean square atomic displacement as a function of time at finite temperatures on the basis of the succession of transitions in a network of states, the vibrational contribution being evaluated on the basis of short molecular dynamics runs artificially trapped within each one of the states. In order to do so, we provide the mathematical formulation for lifting the coarse-grained Poisson process model of transitions between states back to the atomistic level and thereby reproducing the full dynamics of the atomistic system within the Poisson approximation. Our result shows excellent agreement for temperatures around and below the glass transition temperature of our model Lennard-Jones two-component mixtures. Clearly, our approach is able to reproduce the full dynamics of the atomistic system at low temperatures, where the Poisson approximation is valid.

Introduction: Ureteropelvic stenosis occurs as a result of intraluminal or extraluminal alterations at the ureteropelvic junction. It is the most common cause of upper urinary tract obstruction., Case Report: We report about a rare case of a man with ureteropelvic junction obstruction and a renal pelvic stone accompanied by other congenital anomalies, including a sinistral inferior vena cava and agenesis of the opposite kidney. Multiple vessels were present in front of the renal pelvis, while the renal vein itself was situated dorsal to the left renal pelvis, resulting in compression and obstruction of the ureteropelvic junction. Dismembered pyeloplasty using the Anderson-Hynes technique was performed placing the ureter dorsal to the renal vein., Conclusion: Various vascular anomalies, especially in the region of the vena cava, can result in renal vasculature abnormalities and development of secondary ureteropelvic stenosis. Ureteropelvic stenosis may coexist with other congenital defects.

From 1994 to 1998, 54 Tenckhoff peritoneal catheters were implanted in 49 patients undergoing continuous ambulatory peritoneal dialysis. The implantation technique included bedside insertion of peritoneal catheters via trocar under local anesthesia. Early and late complications of this technique were comparable with surgical techniques. Cumulative survival of all catheters was 91% after one year, 78% after two years, 71% after three years, and 68% after four years. Our results suggest that the percutaneous technique for insertion of peritoneal catheters remains an easy, safe, and useful technique in the management of end-stage renal disease patients.