Search results for " Cavity"

Effectiveness of a new method of disinfecting the root canal, using Er, Cr:YSGG laser to kill Enterococcus faecalis in an infected tooth model.

2013

Some lasers have demonstrated to provide effective disinfection when used as adjunctive device to the conventional treatment. The aim of this in vitro study was to determine the effectiveness of the erbium, chromium:yttrium scandium gallium garnet (Er, Cr:YSGG) laser by measuring its bactericidal effect inside the root canal experimentally colonized with Enterococcus faecalis. The laser was tested at different irradiation times (30 and 60 s) and energy of impulses (75 and 25 mJ). A total of 52 single-rooted extracted human teeth were endodontically prepared with rotary instrumentation. All were sterilized and inoculated with a suspension of E. faecalis (105 bacteria/ml). The teeth were rand…

Stafne bone cavity: Magnetic resonance imaging

2006

A case of Stafne bone cavity (SBC) affecting the body of the mandible of a 51-year-old female is reported. The imaging modalities included panoramic radiograph, computed tomography (CT) and magnetic resonance (MR) imaging. Panoramic radiograph and CT were able to determine the outline of the cavity and its three dimentional shape, but failed to precisely diagnose the soft tissue content of the cavity. MR imaging demonstrated that the bony cavity is filled with soft tissue that is continuous and identical in signal with that of the submandibular salivary gland. Based on the MR imaging a diagnosis of SBC was made and no further studies or surgical treatment were initated. MR imaging should be…

Accuracy of Computer-Aided Dynamic Navigation Compared to Computer-Aided Static Procedure for Endodontic Access Cavities: An In Vitro Study

2020

: Purpose: To analyze the accuracy of two computer-aided navigation techniques to guide the performance of endodontic access cavities compared with the conventional access procedure. Materials and Methods: A total of 30 single-rooted anterior teeth were selected, which were randomly distributed into three study groups: Group A&mdash

Proprietà e applicazioni a microonde del MgB2

2008

Microwave response of a cylindrical cavity made of bulk MgB2 superconductor

2008

We report on the microwave properties of a resonant cylindrical cavity made of bulk MgB2 superconductor, produced by the reactive liquid Mg infiltration process. The frequency response of the cavity has been measured in the range 5-13GHz. Among the various modes, the TE011, resonating at 9.79GHz, exhibits the highest quality factor. For this mode, we have determined the temperature dependence of the quality factor, obtaining values of the order of 10^5 in the temperature range 4.2-30K. The values of the surface resistance deduced from the measurements of the quality factor agree quite well with those independently measured in a small sample of MgB2 extracted from the same specimen from whic…

Superconducting Microwave Cavity Made of Bulk MgB2

2006

We report the successful manufacture and characterization of a microwave resonant cylindrical cavity made of bulk MgB2 superconductor (Tc = 38.5 K), which has been produced by the Reactive Liquid Mg Infiltration technique. The quality factor of the cavity for the TE011 mode, resonating at 9.79 GHz, has been measured as a function of the temperature. At T = 4.2 K, the unloaded quality factor is 2.2x10^5; it remains of the order of 10^5 up to T ~ 30 K. We discuss the potential performance improvements of microwave cavities built from bulk MgB2 materials produced by reactive liquid Mg infiltration.

Nest modifications by the acorn ant Temnothorax crassispinus (Hymenoptera: Formicidae)

2019

Many ant species construct nests and during the process considerably influence the environment such as by changing soil structure and creating new habitat for other species. However, other ant species dwell in ready-for-use cavities. Ants of the genus Temnothorax inhabit small cavities such as acorns and under rocks, but under natural conditions, good nest sites are limited resources. During field and laboratory experiments, I studied how the acorn ant Temnothorax crassispinus (Karawajew, 1926) modifies nesting sites. Temnothorax crassispinus is a forest species, which typically lives in cavities in fallen twigs and acorns; colonies usually number from a few dozen to about 200 workers. Alth…

Acorn Ants May Create and Use Two Entrances to the Nest Cavity

2021

Many ant species construct large nests that are inhabited by numerous workers, but other species dwell in ready-for-use cavities and live in small colonies. Ants of the genus Temnothorax inhabit small cavities, e.g., in acorns, twigs, and under rocks. Although a preference for nest sites with a narrower entrance is known, recent studies have shown that they also use cavities with wider entrances and may modify the size of such entrances. As good cavities for nest sites are a limited resource, the possibility to modify a potential nest site, including a reduction in the size of the hole, should be a favorable matter for the ants. Through field and laboratory experiments, I studied the acorn …

Thermalization and condensation in an incoherently pumped passive optical cavity

2011

International audience; We study theoretically and numerically the condensation and the thermalization of classical optical waves in an incoherently pumped passive Kerr cavity. We show that the dynamics of the cavity exhibits a turbulent behavior that can be described by the wave turbulence theory. A mean-field kinetic equation is derived, which reveals that, in its high finesse regime, the cavity behaves essentially as a conservative Hamiltonian system. In particular, the intracavity turbulent field is shown to relax adiabatically toward a thermodynamic equilibrium state of energy equipartition. As a consequence of this effect of wave thermalization, the incoherent optical field undergoes …

Cavités plasmoniques et nanosources optiques

2013

Optical microcavities exhibit high resonance quality, so that, they are of key interest for the design of low-threshold lasers or for achieving strong coupling regime. But, such systems support modes whose the volume remain diffraction limited.In this manuscript, we are interested in their plasmonic counterparts because they support confined modes at the sub-wavelength scale. First, we study an in-plane plasmonic cavity which is the transposition of 1D optical cavity to surface wave. We characterize the cavity by measuring the fluorescence lifetime of dye molecules deposited inside.Then, we are interested in 3-dimension mode confinement achieved by spherical metal nanoparticles. We discuss …