objectives : cleaning and shaping of the root canal system is an important step in endodontic therapy. new instruments incorporate new preparation techniques that can improve the efficacy of cleaning and shaping. the aim of this study was to compare the efficacy of mtwo and race rotary file systems in straightening the canal curvature using only one file or the conventional method. materials an...

The interaction of work fluid mechanics with that of the rotary system itself, basically composed of axes, bearings and rotors, is performed by inserting equivalent dynamic coefficients in the mathematical model of the rotor, the latter being obtained by the finite element method. In this paper, the dynamic coefficients of inertia, stiffness and damping of the flat seals analyzed here are evalu...

The theory of rotary resonance in multiple-quantum magic-angle spinning (MQMAS) experiment is presented. The rotary resonance effect can enhance the efficiency of MQMAS experiment for high-resolution NMR spectra of half-integer quadrupolar nuclei [J. Chem. Phys. 114 (2001) 4618]. Using a spin-1/2 formalism and Floquet theorem, the spin dynamics of a spin-3/2 under rf irradiation and magic-angle...

INTRODUCTION The retreatability of recent calcium silicate or mineral trioxide aggregate (MTA) sealers has not yet been assessed. The aim of this study was to evaluate the removal of 2 MTA-based sealers (MTA Fillapex [Angelus Soluções Odontológicas, Londrina, PR, Brazil] and MTA Plus [Prevest-Denpro, Jammu City, India]) using a rotary retreatment system, considering an epoxy resin sealer (AH Pl...

We report a systematic computational investigation of the possibility to accelerate the rate-limiting thermal isomerizations of the rotary cycles of synthetic light-driven overcrowded alkene-based molecular motors through modulation of steric interactions. Choosing as a reference system a second-generation motor known to accomplish rotary motion in the MHz regime and using density functional th...

in order to comparison of weeds mechanical control for sugar beet, a rotary cultivator was designed and constructed in first year, and compared with other mechanical control in second year. five treatments, included: rotary hoe cultivator, furrower cultivator, rotary cultivator, no weeding and manual weeding were compared. experiment design was random complete blocks design (rcbd) with three re...