Chemical Preparation of Bimetallic Fe/Ag Core/Shell Composite Nanoparticles.

Bimetallic iron/silver (Fe/Ag) core/shell nanoparticles were prepared by chemical reduction from ferrous sulfate in the presence of sodium borohydride as a reducing agent in water, followed then by redox transmetalation with addition of silver nitrate (AgNO3) solution. When the reduction temperature was increased from room temperature to 85 °C, Fe nanoparticles with a reduced crystallite size ranging from 5.5 to 2.0 nm resulted. The particles changed from spherical to plate-like morphology as the temperature reached 85 °C. Addition of trisodium citrate was able to protect the precipitated Fe nanoparticles from oxidation; nonetheless, the citrate would facilitate chelation of the Fe clusters so that dense Fe aggregates with a mean diameter greater than 100 nm were found as the concentration of trisodium citrate exceeded 3.33 mM. A continuous Ag film was formed on the Fe surface by the redox transmetalation. This Ag film became a raspberry structure involving preferential deposition of particulate Ag on the Fe particles when the AgNO3 concentration exceeded 76.9 mM. Magnetic saturation was found to reduce with the increasing Ag concentration in the bimetallic composite nanoparticles.

Modified novel technique for improving the success rate of applying seprafilm by using laparoscopy.

STUDY OBJECTIVE: To describe a modified surgical procedure for applying the adhesion barrier Seprafilm laparoscopically. DESIGN: Retrospective analysis with videos and illustrations showing laparoscopic application of Seprafilm. SETTING: University hospital. PATIENTS: Women undergoing fertility-sparing laparoscopic surgery (myomectomy, endometriotic ovarian cyst or dermoid cyst enucleation, and tuboplasty) via a modified technique. INTERVENTION: Two layers of Seprafilm with plastic covering were rolled together and delivered through a 10-mm trocar, and an irrigation tube was used to moisten the Seprafilm and cover the irregular postoperative rough surface of the organ. After application of Seprafilm, the patient was placed in a reverse Trendelenburg position to check whether the Seprafilm remained in situ on the target surgical surface to act as a physical barrier to adhesion development. MEASUREMENTS AND MAIN RESULTS: After changing the patient's position, illustrations and videos showed that the Seprafilm remained on the postoperative surgical surface, creating a site-specific physical barrier. On day 4 after myomectomy, second-look laparoscopy in 2 patients showed that the Seprafilm had become gel-like and remained between the intestine and posterior rough surface of the uterus. There were no systemic second-look laparoscopic data. CONCLUSION: It is feasible and easier to apply Seprafilm adhesion barrier laparoscopically using the modified technique. Further studies are warranted to prove its efficacy after such use.

A novel technique to apply a Seprafilm (hyaluronate-carboxymethylcellulose) barrier following laparoscopic surgeries.

OBJECTIVE: To describe a novel technique for application of a Seprafilm (modified hyaluronate-carboxymethylcellulose) barrier laparoscopically, and to assess the adequacy of coverage of desired sites. DESIGN: Retrospective cohort study. SETTING: University tertiary hospital. PATIENT(S): One hundred twenty-seven patients who underwent fertility-sparing laparoscopic surgery. INTERVENTION(S): The Seprafilm was rolled up in a plastic package, then delivered through the main trocar. It was unrolled and positioned to cover the traumatized surface of the uterus, ovaries, and tubes. During application, the pelvis was photographed, videotaped, and the pictures were reviewed by two surgeons. MAIN OUTCOME MEASURE(S): The adequacy of the application was divided into three levels as to whether the Seprafilm could cover all the traumatized surfaces. RESULTS: Of the first 15 patients, 4 of 15 (26%) had successful coverage of the traumatized surface with the first sheet of Seprafilm. Of the following 112 patients, 97 of 112 (86.5%) had successful coverage with the first sheet. The success rate climbed to 96% after the second or third sheet. The average time for the application of six pieces (one sheet cut into six pieces) was 21 +/- 4 minutes. The posterior cul-de-sac is difficult to apply well. CONCLUSION(S): It is feasible to apply the antiadhesion barrier Seprafilm laparoscopically. Further studies will be needed to assess the efficacy of reducing adhesion following such use.

Design of Talbot array illuminators for three-dimensional intensity distributions.

The self-imaging phenomenon is investigated as the basis for designing diffractive optical elements to generate three-dimensional diffraction patterns. The phase-only diffractive element is related to the intensity distribution at a finite and discrete set of Fresnel diffraction planes by use of the matrix formalism of the fractional Talbot effect. This description provides a framework to determine the degrees of freedom which can be exploited for design. It also helps to identify inherent symmetries of periodic wavefronts, which limit the set of intensity patterns that can be implemented. A simulated annealing algorithm is used to exploit the design freedom. Our discussion includes an example to illustrate observations.