objective: corrosion resistance is among the most important properties of metal alloys used in the oral cavity. consumption of acidic foods reduces the salivary ph and intensifies the corrosion of brackets and orthodontic wires. this study aimed to compare electro galvanic corrosion of different orthodontic brackets and wires and determine the amount of ions released into acidic artificial sali...

Complementing the previous paper in the series, this paper classifies |2|-graded parabolic geometries, listing their important properties: the group G0, the graded tangent bundle gr(T ) and its algebräıc bracket, the relevant cohomology spaces and the standard Tractor bundle T . Several of these geometries are then explored in more detail, and the paper ends with a case study that that partiall...

Abstract. The traditional Hamiltonian structure of the equations governing conservative Rayleigh-Bénard convection (RBC) is singular, i.e. it’s Poisson bracket possesses nontrivial Casimir functionals. We show that a special form of one of these Casimirs can be used to extend the bilinear Poisson bracket to a trilinear generalised Nambu bracket. It is further shown that the equations governing ...

To Vladimir Igorevich Arnol'd with admiration, on occasion of his 60 th birthday. Abstract Heisenberg motion equations in Quantum mechanics can be put into the Hamilton form. The difference between the commutator and its principal part, the Poisson bracket, can be accounted for exactly. Canonical transformations in Quantum mechanics are not, or at least not what they appear to be; their propert...

A series of tests on cold-formed steel (CFS) wall plate system subjected to uplift force at the mid span of the wall plate is presented. The aim of the study was to study the behaviour and identify the modes of failure of CFS wall plate system. Two parameters were considered in these studies: 1) different dimension of U-bracket at the supports and 2) different sizes of lipped Cchannel. The lipp...

BACKGROUND AND AIMS Diverse gauges have been used to measure and determine bracket height for correct bracket positioning. The aim of the present study was to determine and compare bracket positioning accuracy by using height bracket positioning gauge (HBPG) and Boone gauge (BG). MATERIALS AND METHODS Nineteen sets of stone models were prepared from one patient. One set was employed to de-ter...

We present the third in the series of papers describing Poisson properties of planar directed networks in the disk or in the annulus. In this paper we concentrate on special networks Nu,v in the disk that correspond to the choice of a pair (u, v) of Coxeter elements in the symmetric group S n and the corresponding networks N u,v in the annulus. Boundary measurements for Nu,v represent elements ...

Objective: To evaluate the effect of tactile and kinesthetic stimulation on behavioral and clinical development in preterm neonates while still in the hospital. Methods: Thirty-two clinically stable preterm infants weighing <2500 grams, with no significant perinatal asphyxia, were allocated to two groups: a control group (CG) in which no intervention was made (n=16) and a study group (SG) in wh...

For any n ≥ 2 we define an isotopy invariant, 〈Γ〉n , for a certain set of n-valent ribbon graphs Γ in R, including all framed oriented links. We show that our bracket coincides with the Kauffman bracket for n = 2 and with the Kuperberg’s bracket for n = 3. Furthermore, we prove that for any n, our bracket of a link L is equal, up to normalization, to the SUn quantum invariant of L. We show a nu...

INTRODUCTION The aim of this study was to evaluate the differences in quality of life impacts between subjects treated with Invisalign aligners (Align Technology, Santa Clara, Calif) and those with fixed appliances during the first week of orthodontic treatment. METHODS A prospective, longitudinal cohort study involving 60 adult orthodontic patients (33 with Invisalign aligners, 27 with fixed...