Silica glass and polycrystalline alumina slides were implanted with palladium ions. Irradiations at 47 and 2 keV energies have been performed on silica samples, at 2 keV energy on alumina. Different ...fluences have been used in the 10
16 ion cm
−2 range. Samples have been characterized by X-ray and ultraviolet photoelectron spectroscopies (UPS), transmission electron microscopy (TEM), Rutherford backscattering spectrometry (RBS) and optical absorption spectroscopy. In all samples, metallic palladium is present in the form of clusters whose diameter depends on the local dopant concentration. Moreover, palladium silicide compounds have been observed in the 5
×
10
16 Pd
+ cm
−2 implanted silica sample. The valence band of these composites has been measured.
New zinc borate glasses of composition 4PbO·2ZnO·5B
2O
3· and 2PbO·4ZnO·5B
2O
3 doped with Pr
3+, Nd
3+, Eu
3+, Dy
3+, Ho
3+ and Er
3+ were prepared. Absorption and luminescence spectra were measured ...and the Judd–Ofelt parameters were calculated. The spectroscopic behaviour appears to be strongly influenced by the presence of the highly polarizable Pb
2+ ion. The values of stimulated emission cross sections for selected laser transition appear to be relatively high, suggesting that these materials can be considered as interesting candidates for optical applications.
The development and application of three-dimensional unstructured hierarchical spectral/hp element algorithms has highlighted the need for efficient preconditioning for elliptic solvers. Building on ...the work of Bica (Ph.D. thesis, Courant Institute, New York University, 1997) we have developed an efficient preconditioning strategy for substructured solvers based on a transformation of the expansion basis to a low-energy basis. In this numerically derived basis the strong coupling between expansion modes in the original basis is reduced thus making it amenable to block diagonal preconditioning. The efficiency of the algorithm is maintained by developing the new basis on a symmetric reference element and ignoring, in the preconditioning step, the role of the Jacobian of the mapping from the reference to the global element. By applying an additive Schwarz block preconditioner to the low-energy basis combined with a coarse space linear vertex solver we have observed reductions in execution time of up to three times for tetrahedral elements and 10 times for prismatic elements when compared to a standard diagonal preconditioner. Full details of the implementation and validation of the tetrahedral and prismatic element preconditioning strategy are set out below.
Density functional molecular cluster calculations have been used to investigate the interaction of CO with the M2O3(101̄2) (M = Al and Ti) nonpolar surface. The electronic structure of the clean ...surface, the adsorbate geometry, vibrational parameters, and chemisorption enthalpies are computed and discussed. Theoretical results pertaining to the clean surface agree quite well with experimental measurements and other theoretical investigations. As far as the adsorbate−substrate interaction is concerned, our data indicate that the CO−M2O3(101̄2) bonding is charaterized, in both Al2O3 and Ti2O3, by a two-way electron flow involving both donation from CO based σ levels into virtual orbitals of the unsaturated surface Lewis acid site and back-donation from surface states into the CO π* virtual levels. However, the nature of surface orbitals involved in back-donation and the concomitant effects on the adsorbate structure are very different in the two cases. CO is only slightly affected upon chemisorption on Al2O3(101̄2), while perturbations induced into the CO electronic and molecular structure by the interaction with the Ti2O3(101̄2) surface are very intense and, consistently with experimental data, the C−O bond becomes strongly weakened.
To compare the use of low pneumoperitoneum pressure (LPP; 8 mm Hg) vs standard pneumoperitoneum pressure (SPP; 12 mm Hg) during mini-laparoscopic hysterectomy (MLH).
Randomized controlled trial ...(Canadian Task Force classification I).
Tertiary care center.
Forty-two consecutive women scheduled to undergo MLH to treat benign uterine disease.
Women were randomly selected to undergo MLH using LPP (n = 20) or SPP (n = 22). MLH was performed via 3-mm ancillary ports.
The primary outcome was to evaluate changes in abdominal and shoulder-tip pain via a 100-mm visual analog scale at 1, 3, and 24 hours postoperatively. All procedures were completed via mini-laparoscopy without the need to increase intra-abdominal pressure or convert to conventional laparoscopy or open surgery. Intraoperatively, 1 episode of severe bradycardia occurred in the LPP group, whereas no intraoperative complications were recorded in the SPP group (p = .47). No postoperative complications were recorded (p > .99). Abdominal pain was similar between groups at each time point. Incidence and intensity of shoulder-tip pain at 1 and 3 hours postoperatively was lower in the LPP group than in the SPP group (p < .05), whereas no between-group differences were observed at 24 hours (p > .05). Rescue analgesic requirement did not differ statistically between the LPP and SPP groups (20% vs 41%, respectively; p = .19; odds ratio, 2.7; 95% confidence interval, 0.69-11.08).
In experienced hands, use of LPP is safe and feasible. During performance of MLH, compared with SPP, LPP is a simple method that offers advantages of less shoulder-tip pain.
STUDY
To evaluate perioperative outcomes and complications of laparoscopic hysterectomy (LH) in women with giant uteri (≥1.5 kg) compared with open abdominal hysterectomy (AH), which is considered ...the reference.
A retrospective analysis of prospectively collected data (Canadian Task Force Classification II-2).
An academic research center.
All consecutive women who underwent hysterectomy for uteri weighing ≥1500 g (total = 51) between 2000 and 2015 were analyzed. Twenty-seven (53%) patients had been scheduled for the laparoscopic approach (LH), whereas 24 (48%) had been scheduled for AH.
Hysterectomy ± mono/bilateral salpingo-oophorectomy.
Perioperative details, incidence, severity, and type of complications were analyzed according to surgical approach (AH vs LH). We also evaluated the trends over time in terms of perioperative outcomes.
AH was associated with a shorter operative time (97.5 vs 160 minutes, p = .004) compared with LH. Blood loss (200 vs 225 mL, p = .21) and the decrease in postoperative hemoglobin (-1.2 vs -1.1, p = .89) were similar between AH and LH. Intra- and postoperative complications were similar between the 2 groups; however, hospital stay was significantly shorter in the LH group (median = 3 days vs 1 day, p < .001). A significant trend toward a progressive increase in the use of the minimally invasive approach was registered through the years (p = .001). Parallel to this increase, we observed a significant reduction in terms of length of stay. Moreover, a decrease in the total number of complications, mainly because of a decrease in the rate of early minor events, was observed through the years.
Our experience shows that LH can be considered a feasible procedure, even in cases of uteri ≥1.5 kg, with significant advantages over open surgery in terms of postoperative hospital stay.
To investigate the effect of uterine weight on the mode of hysterectomy and on perioperative outcomes and to explore how the increasing experience in endoscopic techniques influenced our choice of ...surgical approach to hysterectomy to treat benign conditions.
Retrospective analysis (Canadian Task Force classification II-2).
University-based department of obstetrics and gynecology.
A series of 1518 consecutive women with benign uterine conditions other than pelvic organ prolapse who underwent hysterectomy at our department between January 2000 and December 2011.
Gradual implementation of the laparoscopic approach over years, with the goal of attempting endoscopic hysterectomy whenever possible and irrespective of uterine weight. Comparisons were made on the basis of various approaches to hysterectomy including vaginal hysterectomy (VH), abdominal hysterectomy (AH), and total laparoscopic hysterectomy (TLH) and on uterine weight.
Hysterectomies performed included 568 VH (37.4%), 234 AH (15.4%), and 716 TLH (47.2%). Postoperative complications were lower in the TLH group vs the AH group; no significant difference was observed between the VH vs TLH groups or the AH vs VH groups. A marked reduction in the need for open surgery was noted between 2000 and 2011 (p for trend <.001). Restricting the analysis to TLH, an increase in operative time and blood loss was observed, parallel to increasing uterine weight. Hospital stay and rate of intraoperative and postoperative complications were independent of uterine weight. In 45 women with uterus weight ≥1000 g, the initial approach was via laparoscopy, with a success rate of 95.6% (n = 43). A marked tendency toward reduction in the use of open surgery was observed through the years when uterine weight was ≥1 kg (p for trend <.001).
Systematic implementation of laparoscopic hysterectomy enables a marked reduction in the need for AH. In experienced hands, even very large uteri (≥1 kg) can be safely removed via laparoscopy.
The modality of surgical specimen extraction is extremely important in the setting of minimally invasive operations. To assess the feasibility, safety, and applicability of transvaginal specimen ...extraction through posterior colpotomy in women with uterus in situ, we present our 11-year experience with this technique and perform a systematic review of the available studies in the field of gynecologic laparoscopy.
A retrospective analysis and systematic review of the literature (Canadian Task Force classification II-2).
A tertiary care center.
Two hundred thirty women with uterus in situ undergoing minimally invasive surgery for gynecologic disease at our institution with transvaginal specimen removal in the period between 2001 and 2012. We then reviewed 17 studies, collecting data on a total of 899 transvaginal retrieval procedures.
Transvaginal specimen retrieval after operative laparoscopy.
Overall, 259 retrieval procedures were performed in the 230 patients operated on at our institution (including extraction of adnexal specimens n = 190, uterine myomectomies n = 36, bowel resections n = 17, and other n = 16). All interventions were completed laparoscopically. Two (0.8%) women required secondary surgery because of postoperative intraperitoneal bleeding. Three additional (1.3%) minor postoperative complications were observed. No intra- and postoperative complications associated with the extraction technique occurred. In our literature review, a total of 58 (6.5%) complications were recorded. Only 1 (0.1%) adverse event was related to the transvaginal extraction procedure.
Our data suggest that transvaginal specimen retrieval after operative laparoscopy represents a safe, feasible, and applicable technique. Further research is needed to assess the real advantages of this natural orifice extraction procedure.
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