RESUMO
The magnetic cooling effect originates from a large change in entropy by the forced magnetization alignment, which has long been considered to be utilized as an alternative environment-friendly cooling technology compared to conventional refrigeration. However, an ultimate timescale of the magnetic cooling effect has never been studied yet. Here, we report that a giant magnetic cooling (up to 200 K) phenomenon exists in the Co/Pt nano-multilayers on a femtosecond timescale during the photoinduced demagnetization and remagnetization, where the disordered spins are more rapidly aligned, and thus magnetically cooled, by the external magnetic field via the lattice-spin interaction in the multilayer system. These findings were obtained by the extensive analysis of time-resolved magneto-optical responses with systematic variation of laser fluence as well as external field strength and direction. Ultrafast giant magnetic cooling observed in the present study can enable a new avenue to the realization of ultrafast magnetic devices.The forced alignment of magnetic moments leads to a large change in entropy, which can be used to reduce the temperature of a material. Here, the authors show that this magnetic cooling effect occurs on a femtosecond time scale in cobalt-platinum nano-multilayers.
RESUMO
This paper presents a case series of furcation involved teeth complicated with endodontic involvement which were treated with periodontal, endodontic and restorative procedures using different bone regenerative materials like; (a) Calcium phosphosilicate bone substitute having bioactive glass 69% mixed with glycerin 19% and poly-ethylene 12% dispensed in a putty form; (b) hydroxyapatite 70% and ß-tricalcium phosphate 30% dispensed in granular form. All the cases were randomly selected having Grade II furcation defect with primary or secondary endodontic involvement. All cases were under observation for a period of 9 months. Measurements at 9 months post-surgery demonstrated that dental putty as bone graft substitute which was in combination of bioactive glass mixed with glycerine and polyethylene glycol showed better result as compared granular bone graft which was in combination of hydroxyapatite and ß-tricalcium phosphate.
RESUMO
BACKGROUND: As per many studies endodontically treated teeth are widely considered to be more susceptible to fracture than vital teeth. Obturation strains and post placement have been a major cause of vertical root fracture. Present study was conducted to compare in vitro fracture resistance after filling with either Gutta-percha or Resilon by lateral condensation techniques in root canals. This study evaluated a new thermoplastic synthetic polymer based on polyester, which contains bioactive and radiopaque filler, Resilon performs every way as Gutta-percha except that it allows the bonding agent to attach to the resin core and the dentin wall thus forming a monoblock. MATERIALS AND METHODS: In the present study 90 freshly extracted single-rooted human mandibular premolar teeth endodontically treated, were cut at the cemento-enamel junction, and were randomly divided into three groups of 30 each as teeth of Group A (Control) received no obturation, Group B teeth were obturated using Gutta-percha/AH26, and Group C teeth were obturated using Resilon/Epiphany obturating kit. Each specimen were mounted in acrylic in a polyvinyl ring and then tested for fracture resistance with the help of an universal testing machine. A compressive force was applied until the root is fractured. The data were subjected to analysis of variance for comparing mean difference of fracture resistance among three groups. Multiple comparisons among these groups were carried out by non-parametric Kruskal-Wallis analysis. A p value of <0.0001 was considered a statistically significant difference. RESULTS: The results obtain after analysis showed no significant differences in the fracture resistance between the two tested groups of endodontic sealers. CONCLUSION: Within the limitation of the present in-vitro study, Resilon/Epiphany sealer performs better than Gutta-percha/AH 26 sealer with lateral condensation technique.