BACKGROUND AND OBJECTIVES This study was conducted to evaluate the effect of two soft drinks, Coca-Cola and Mirinda orange on bracket bond strength, on adhesive remnant on teeth after debonding the bracket, and to observe by means of scanning electron microscope (SEM) the effect of these drinks on intact and sealed enamel. METHODS 120 non-carious maxillary premolar teeth already extracted for...

INTRODUCTION Bracket debonding from the tooth surface is a common problem in fixed orthodontics. The aims of the present study were to assess the bond strength and failure sites in two ways of bonding technique, with metallic and ceramic brackets. MATERIALS AND METHODS One hundred premolars were assigned to 4 groups of 25 each: Group A, metallic brackets/conventional procedure; Group B, metal...

In order to study the application of lime-fly ash loess in permafrost subgrade engineering, uniaxial compressive test, fast direct shearing test and permeability tests were carried out on lime-fly ash loess under different curing ages and freeze-thaw cycles. Uniaxial compressive strength of lime-fly ash loess increases slowly with the curing ages, and can reach 3.5 Mpa after the curing ages of ...

The tensile properties of a Ni-Co-based superalloy were investigated from room temperature to 900 °C. From 25 650 °C, the yield strength and alloy decreased slightly, while elongation sharply. 760 °C greatly reduced, also had low value. With increase in temperature, deformation mechanism transformed anti-phase boundary shearing stacking fault shearing, then twinning Orowan bypassing, respective...

The mechanical response of clay mass can be significantly affected by the distribution and arrangement of the particles and the interaction between them. A series of compression and extension tests under drained and undrained conditions were performed on normally consolidated and heavily over-consolidated clay specimens with different microfabric. The experimental data indicates strong influenc...

A computer-controlled display of random dots was used to study perceptions of depth. In this display, a field of stationary random dots surrounded a rectangular area in which random dots moved with uniform velocity in a single direction. The boundaries of this rectangle did not move. When dot motion was perpendicular to the longer boundary of the rectangle (occluded motion), the rectangle seeme...

We study large-scale dynamo action due to turbulence in the presence of a linear shear flow. Our treatment is quasilinear and equivalent to the standard "first-order smoothing approximation." However it is non perturbative in the shear strength. We first derive an integrodifferential equation for the evolution of the mean magnetic field, by systematic use of the shearing coordinate transformati...

It is shown by enzymatic digestion of chromatin from rat liver or Guerin ascites tumour (GAT) that treatments, which abolish the 180 base pair repeat, as revealed by digestion with micrococcal nuclease (shearing in salt solutions of medium ionic strength, sonication, fixation with formaldehyde in the presence of 5 M urea), have little effect on the 10 nucleotide repeat, observed in deoxyribonuc...