R.M.S. dos Reis

Modified uterine manipulator and vaginal rings for total laparoscopic radical hysterectomy

At present, there is no standard technique that allows surgeons performing total laparoscopic radical hysterectomy to complete the colpotomy and remove an adequate (2-cm) margin of upper vaginal tissue while maintaining adequate pneumoperitoneum. We evaluated the feasibility and safety of using a modified uterine manipulator for total laparoscopic radical hysterectomy in patients with cervical or endometrial cancer. A retrospective review was performed in all patients who underwent total laparoscopic radical hysterectomy using a modified uterine manipulator at our institution during the period April 2004 to December 2006. This analysis included 30 patients who underwent surgery with the modified uterine manipulator. There were no reports of difficulty with placement of the instrument, multiple attempts at placement, difficulty with uterine manipulation, or uterine perforation. In no patient was a vaginal incision or episiotomy required to fit the instrument through the introitus. In no case was there loss of pneumoperitoneum during colpotomy. Additional upper vaginal tissue had to be removed after intraoperative assessment of the adequacy of the surgical specimen in five (16.7%) of 30 patients. Use of the modified uterine manipulator according to our technique is safe and feasible, allowing for adequate vaginal resection and maintenance of pneumoperitoneum

Ion beam synthesis of cubic-SiC layer on Si(111) substrate

We have investigated SiC layers produced by ion beam synthesis on Si(111) substrates using different procedures. Bare Si(111) and SiO2∕Si(111) structures were implanted with carbon at 40keV up to a fluence of 4×1017cm−2 at a temperature of 600°C. Postimplantation annealing was carried out at 1250°C for 2h in pure O2 or Ar (with 1% of O2). A SiC layer was synthesized for all the procedures involving annealing under Ar. However, for the samples annealed under pure O2 flux, only that employing implantation into the bare Si(111) resulted in SiC synthesis. Rutherford backscattering spectrometry shows that, after annealing, the stoichiometric composition is obtained. Transmission electron microscopy measurements demonstrate the synthesis of cubic-SiC layers that are completely epitaxial to the Si(111) substrate. However, there is a high density of nanometric twins, stacking faults, and also narrow amorphous inclusions of laminar shape between the crystalline regions. The procedure based on high temperature impl...

Carbon redistribution in nanometric Si1−xCx layers upon ion beam synthesis of SiC by C implantation into SIMOX(1 1 1)

Nanometric 3C SiC layers (~40 nm) between amorphous zones, i.e. SiO2/SiC/SiO2/Si, have been obtained using separation by implantation of oxygen (SIMOX) structures on bulk Si(1 1 1) as the starting material, i.e. Si(65 nm)/SiO2/Si(1 1 1) structures. We report mechanisms of carbon redistribution in the starting 65 nm silicon overlayer (SOV) upon SiC ion beam synthesis (IBS). Sequential C implantation steps (sample held at 600 °C), with 1250 °C annealing in between, have allowed us to register the evolution of the carbon composition (previously and after annealing) in the SOV under conversion when increasing the implantation fluence. Rutherford backscattering spectrometry (RBS) and transmission electron microscopy (TEM) reveal a two-sublayer structure of about the same thickness for the layer under conversion. The composition evolution of the sublayers (Si1−xCx) was monitored by evaluating Si composition changes measured by RBS analysis. High resolution TEM has demonstrated major differences in the structural quality of sublayers. We suggest that the observed structural differences are the main driving force for the observed C migration.