TRANSPERITONEAL LAPAROSCOPIC ADRENALECTOMY IN CHILDREN: INITIAL EXPERIENCE

PURPOSE: The use of mini-invasive approach for adrenalectomy is poorly defined in pediatric patients, although laparoscopic adrenalectomy is considered a standard procedure in adults. The aim of our study is to describe the safety and feasibility of minimally invasive adrenalectomy in children based on surgical skills and results. MATERIALS AND METHODS: This is a retrospective study of four pediatric laparoscopic adrenalectomies performed in our centre between 2009 and 2012. All patients underwent transperitoneal lateral laparoscopic adrenalectomy two of which were right adrenalectomies and two were left. RESULTS: Four laparoscopic adrenalectomies were performed. Indications for surgery were neuroblastoma in two patients, secernent adrenocortical tumor in one patient and adrenocortical nodular hyperplasia in the last one. Patients had a mean age of 87 months (range 17-156) at diagnosis and the average lesion size was 3.23 cm (range 0.7-6.4). All laparoscopic adrenalectomies were successful, no conversions to open surgery were required and no post- operative complications or deaths occurred. The average operating time was 105 minutes (range 80-130), blood loss during surgery was minimal and the mean post-operative hospital stay was 3.75 days (range 3-5). None of the patients showed signs of recurring disease at 15-months follow- up. CONCLUSIONS: Laparoscopic adrenalectomy is a safe, feasible and reproducible technique offering numerous advantages including shortening of operating times and post-operative hospital stays, as well as reduction of blood loss and complications. It also provides good visibility and easy access to other organs

Laparoscopic Adrenalectomy in Children

Adrenalectomia VL in età pediatrica: indicazioni e tecnica chirurgic

Chemisorption sites and reaction pathways for acetylene on Si(111)-(7x7)

The interaction between the acetylene molecule (C2H2) and the Si(1 1 1)-(7 x 7) surface is studied using both ab initio and empirical methods. Several possible chemisorption configurations are explored, which may be helpful to rationalize recent experimental results. The kinetics of the chemisorption process is also studied by means of accurate ab initio calculations, and low-energy paths leading to stable configurations are identified. It is shown that large-scale calculations based on the use of semi-empirical potentials, in tight cooperation with ab initio calculations, can be an efficient tool to achieve a broad overview of the chemisorption reactions of molecules occurring on complex semiconductor surfaces

Acetylene on Si(111) from computer simulations

The interaction between the acetylene molecule (C_2H_2) and the Si(111)-(7 x 7) surface is studied with the combined use of ab initio and empirical methods. Several possible chemisorption configurations are explored, which may be helpful to rationalize recent experimental results. The kinetics of the chemisorption process can be described by identifying the low-energy paths between pairs of stable configurations. This can be done by means of accurate ab initio calculations only for small-scale models of surface reconstructions. It is shown that large-scale calculations based on the use of semi-empirical potentials, validated by ab initio calculations for small-scale models, can be an efficient tool to study chemisorption reactions of molecules occurring on complex semiconductor surfaces

Ab initio investigation of the adsorption of organic molecules at Si(111) and Si(100) surfaces

I To investigate the early stages of SiC growth on silicon, we performed an ab initio study of the adsorption of C2H2 and other small organic molecules on different Si surfaces. Our calculations, based both on geometry optimization and on finite-temperature molecular dynamics simulations, show that for all the molecules that we have considered the preferred adsorption sites at low temperature are confined at the surface, with no sub-surface penetration. Adsorption occurs through the formation of Si-C bonds, accompanied by a distortion of the adsorbed molecule to adapt the Si-C distance to the SiC bulk bond length. We discuss similarities and differences upon changing the organic molecule and the crystal face. To complete the study with the computation of directly measurable quantities, we analyze the optical reflectance anisotropy of one simulated structure. (C) 2003 Elsevier Science B.V. All rights reserved

The suitability of disintegrating force kinetics for studying the effect of manufacturing parameters on spironolactone tablet properties

The aim of this paper was to study the effect of the granulate properties and tablet compression force on disintegrating force behavior in order to investigate the capability of the disintegrating force to characterize tablets that have the same composition but were manufactured in different conditions. Several tablets containing spironolactone in the external or internal granulated mixture of calcium carbonate and maize starch differing in particle size distribution, were prepared at 3 compression levels. The force developed by tablets during water uptake and disintegration was measured and plotted versus time. The curves obtained were analyzed by the Weibull equation in order to calculate the parameters characterizing the tablet disintegration kinetics. The disintegrating force time parameter, the maximum force developed, and the area under the curve were determined. In general, the reduction of time parameter value and/or the increase in maximum force developed corresponded to an acceleration in tablet disintegration. In addition, the area under the force curve increased in stronger tablets, monitoring in a sensitive way the tablet structural changes introduced by compression force. The results showed that the disintegrating force measurement can detect small changes in the structure of the tablet that cannot be discriminated by pharmacopoeia tests. The effect of manufacturing, in particular compression force, on tablet properties was quantified by the parameters of disintegrating force kinetics

The effect of residual water on antacid properties of sucralfate gel dried by microwaves

The aim of this work was to study the acid neutralization characteristics of microwave-dried sucralfate gel in relation to the water content and physical structure of the substance. Several dried sucralfate gels were compared with humid sucralfate gel and sucralfate nongel powder in terms of neutralization rate and buffering capacity. Humid sucralfate gel and microwave-dried gel exhibited antacid effectiveness. In particular, the neutralization rate of dried gel powders was inversely related to the water content: as the water content of dried powders decreased, the acid reaction rate linearly increased. The relationship was due to the different morphology of dried sucralfate gels. In fact, the porosity of the dried samples increased with the water reduction. However, the acid neutralization equivalent revealed that the dried sucralfate gel became more resistant to acid attack in the case of water content below 42%. Then, the microwave drying procedure had the opposite effect on the reactivity of the aluminum hydroxide component of dried sucralfate gel powders, since the rate of the reaction increased whereas the buffering capacity decreased as the amount of water was reduced