dr. elahe yazdani

We have reported the fabrication of boric acid incorporated into surface of magnetite nanoparticles. The catalyst was characterized using spectroscopic, magnetic and thermal techniques (FT-IR, SEM, XRD, ICP, VSM and TGA). It catalyzed Mukaiyama aldol reaction of a ketene silyl acetal type nucleophile ((1-methoxy-2-methylprop-1-enyloxy) trimethylsilane), and various aldehydes (aromatic, aliphatic, α,β-unsaturated), in acetonitrile and the yields were in the range of 45-98%. Magnetic Fe3O4-boric acid was multi-functional. The Fe3O4 core of the catalyst made easy separation and recycling while its boric acid portion catalyzed Mukaiyama aldol reaction. Nano size nature of the catalyst increased its activity in a way that boric acid, which is a weak Lewis acid, functioned similar to a more strong one like BF3. Boric acid functionality had the advantage of being moisture insensitive, economically reasonable and environmentally friendly. Furthermore Fe3O4@ SiO2@Boric acid was magnetically recovered via an external permanent magnet and was reused at least 6 times with a negligible change in its activity.

Diagnosis of periapical pathology is of paramount importance in enabling the clinician to provide immediate and appropriate dental treatment. Both intraoral digital radiography and film radiography are used to detect periapical pathology. The purpose of this study was to compare the accuracy of digital radiographic imaging with conventional radiography in detecting chemically created lesions. For conducting this experimental study one cow cadaver mandibular Jaw was used. After building four 1×1cm2 pools at first molar areas, 35% Hydrochloric acid solution used to create chemically lesions. The designed time for chemically lesions was 4, 12, 24 and 36 hrs following acid exposure. Then, 1 digital and 1 conventional image with E-Speed film was taken from each half-jaw and images evaluated by five examiners. Wilcoxon signed Ranks test used for statistical analysis. The results of this study showed that diagnosis were more precise in detecting lesions with RVG than conventional radiography. This difference was statistically significant (p<0.05). Regarding the acceptable quality of digital radiographs comparing to conventional radiographs we suggest using this method for detecting bone lesions.