Introduction: The aim of this study was to assess the galvanic behavior of different bracket and archwire combinations that are commonly used in orthodontic treatments. Methods: Three types of orthodontic archwires with a diameter of 0.016×0.022 inch and 80 standard edgewise maxillary central incisor brackets were selected. Three groups consisted of different wire-bracket couples and one group ...

OBJECTIVE This article aims to analyze the difference in stresses generated in the bracket-cement-tooth system by means of a peel load in single and double-mesh bracket bases using a three-dimensional finite element computer model. MATERIAL AND METHODS A three-dimensional finite element model of the bracket-cement-tooth system was constructed and consisted of 40,536 bonds and 49,201 finite el...

Tensile bond strength and bond failure location were evaluated in vitro for two types of aesthetic brackets (non-silanated ceramic, polycarbonate) and one stainless steel bracket, using bovine teeth as the substrate and diacrylate resin as the adhesive. The results show that metallic bracket had the highest bond strength (13.21 N) followed by the new plastic bracket (12.01 N), which does not re...

Gene rearrangements within the process of gene assembly in ciliates can be represented using a 4-regular graph. Based on this observation, Burns et al. [Discrete Appl. Math., 2013] propose a graph polynomial abstracting basic features of the assembly process, like the number of segments excised. We show that this assembly polynomial is essentially (i) a single variable case of the transition po...

statement of problem: bracket de-bonding during initial orthodontic archwire placement immediately after bracket set up or following re-bonding a single bracket can be a clinical concern. purpose: the aim of this in vitro study was to assess the effect of time on the shear bond strength of a no-mix orthodontic composite adhesive. materials and methods: seventy freshly extracted human upper firs...

Orthogonal separability of finite-dimensional Hamiltonians is characterized by using various geometrical concepts, including Killing tensors, moving frames, the Nijenhuis tensor, bi-Hamiltonian and quasi-bi-Hamiltonian representations. In addition, a complete classification of separable metrics defined in two-dimensional locally flat Lorenzian spaces is presented.

By counting flags in finite vector spaces, we obtain a q-multinomial analog of a recursion for q-binomial coefficients proved by Nijenhuis, Solow, and Wilf. We use the identity to give a combinatorial proof of a known recurrence for the generalized Galois numbers.

Abstract. In this paper, we have studied a conformal transformation between two almost Hermitian manifolds and shown that the associated Nijenhuis tensor is conformally invariant under this transformation. We have also discussed the properties of contravariant almost analytic vector field, covariant almost analytic vector field and some other properties in almost Hermitian manifold under this t...

It is shown that a class of dynamical systems (encompassing the one recently considered by F. Calogero in [1]) is both quasi-bi-Hamiltonian and bi-Hamiltonian. The first formulation entails the separability of these systems; the second one is obtained trough a non canonical map whose form is directly suggested by the associated Nijenhuis tensor.

The symmetric group is generated by σ = (1 2 ··· n) and τ = (1 2). We answer an open problem of Nijenhuis and Wilf by constructing a Hamilton path in the directed Cayley graph for all n, and a Hamilton cycle for odd n. Dedicated to Herb Wilf (1931 – 2012).