Fluoridated elastomers: effect on disclosed plaque

OBJECTIVE: To investigate the effect of fluoridated elastomers on the quantity of disclosed dental plaque surrounding an orthodontic bracket in vivo. DESIGN: A randomized, prospective, longitudinal clinical trial, employing a split mouth, crossover design. Setting: The Orthodontic Departments of Liverpool and Sheffield Dental Hospitals. Subjects and methods: The subjects were 30 individuals about to start fixed orthodontic treatment. The study consisted of two experimental periods of 6 weeks with a washout period between. Fluoridated elastomers were randomly assigned at the first visit to be placed around brackets on 12, 11, 33 or 22, 21, 43. Non-fluoridated elastomers were placed on the contra-lateral teeth. After 6 weeks (visit 2) the elastomers were removed, the teeth disclosed and a photograph taken. Non-fluoridated elastomers were placed on all brackets for one visit to allow for a washout period. At visit 3, fluoridated elastomers were placed on the contra-lateral teeth to visit 1. At visit 4, the procedures at visit 2 were repeated. The photographs were scanned, then the area and proportion of the buccal surface covered with disclosed plaque was measured using computerized image analysis. A mixed-effects ANOVA was carried out with the dependent variable being the area or percentage area of disclosed plaque. RESULTS: There was no evidence of a systematic error and substantial agreement for the repeat readings of the same images. The only significant independent variable for the area of disclosed plaque was the subject (p<0.001). The significant independent variables for the proportion of disclosed plaque were the subject (p<0.001) and the tooth type (p=0.002). The independent variable describing the use of fluoridated or non-fluoridated elastomers was not significant for either the area or the proportion of disclosed plaque. CONCLUSION: Fluoridated elastomers do not affect the quantity of disclosed plaque around an orthodontic bracket

Ground-state phase diagram for a system of interacting, D(D3)D(D_3) non-Abelian anyons

We study an exactly solvable model of $D(D_3)$ non-Abelian anyons on a one-dimensional lattice with a free coupling parameter in the Hamiltonian. For certain values of the coupling parameter level crossings occur, which divide the ground-state phase diagram into four regions. We obtain explicit expressions for the ground-state energy in each phase, for both closed and open chain boundary conditions. For the closed chain case we show that chiral phases occur which are characterised by non-zero ground-state momentum.Comment: 21 pages, accepted to be published in Nucl. Phys.

Resin-modified glass ionomer cement vs composite for orthodontic bonding: A multicenter, single-blind, randomized controlled trial

Introduction In this study, we aimed to compare the incidence of new demineralized lesions and bond failures between 2 groups of participants wearing fixed orthodontic appliances bonded with either light-cured resin-modified glass ionomer cement or light-cured composite. Methods This trial was a multicenter (6 centers: 2 teaching hospitals, 4 specialist orthodontic practices), single-blinded, randomized controlled trial with 2 parallel groups. Patients aged 11 years or older, in the permanent dentition, and about to start fixed orthodontic treatment in these 6 centers were randomly allocated to have either resin-modified glass ionomer cement or light-cured composite for bonding brackets, forward of the first molars. Pretreatment and day-of-debond digital photographic images were taken of the teeth and assessed by up to 5 clinical and 3 lay assessors for the presence or absence of new demineralized lesions and the esthetic impact. The assessors were masked as to group allocation. Results We randomized 210 participants, and 197 completed the trial. There were 173 with complete before-and after-digital images of the teeth. The incidence of new demineralized lesions was 24%; but when the esthetic impact was taken into account, this was considerably lower (9%). There was no statistically significant difference between the bracket adhesives in the numbers with at least 1 new demineralized lesion (risk ratio,1.25; 95% confidence interval, 0.74-2.13; P = 0.403) or first-time bracket failure (risk ratio,0.88; 95% confidence interval, 0.67-1.16; P = 0.35). There were no adverse effects. Conclusions There is no evidence that the use of resin modified glass ionomer cement over light-cured composite for bonding brackets reduces the incidence of new demineralized lesions or bond failures. There might be other reasons for using resin modified glass ionomer cement

A comparative histological study of the osteoderms in the lizards Heloderma suspectum (Squamata: Helodermatidae) and Varanus komodoensis (Squamata: Varanidae)

This is the peer reviewed version of the following article: Kirby, A, Vickaryous, M, Boyde, A, et al. A comparative histological study of the osteoderms in the lizards Heloderma suspectum (Squamata: Helodermatidae) and Varanus komodoensis (Squamata: Varanidae). J Anat. 2020; 00: 1– 9. https://doi.org/10.1111/taja.13156 which has been published in final form at https://doi.org/10.1111/taja.13156

Dynamic scaling and aging phenomena in short-range Ising spin glass: Cu0.5_{0.5}Co0.5_{0.5}Cl2_{2}-FeCl3_{3} graphite bi-intercalation compound

Static and dynamic behavior of short-range Ising-spin glass Cu$_{0.5}$Co$_{0.5}$Cl$_{2}$-FeCl$_{3}$ graphite bi-intercalation compounds (GBIC) has been studied with SQUID DC and AC magnetic susceptibility. The $T$ dependence of the zero-field relaxation time $\tau$ above a spin-freezing temperature $T_{g}$ (= 3.92 $\pm$ 0.11 K) is well described by critical slowing down. The absorption $\chi^{\prime\prime}$ below $T_{g}$ decreases with increasing angular frequency $\omega$, which is in contrast to the case of 3D Ising spin glass. The dynamic freezing temperature $T_{f}(H,\omega)$ at which d$M_{FC}(T,H)/$d$H=\chi^{\prime}(T,H=0,\omega)$, is determined as a function of frequency (0.01 Hz $\leq \omega/2\pi \leq$ 1 kHz) and magnetic field (0 $\leq H \leq$ 5 kOe). The dynamic scaling analysis of the relaxation time $\tau(T,H)$ defined as $\tau = 1/\omega$ at $T = T_{f}(H,\omega)$ suggests the absence of SG phase in the presence of $H$ (at least above 100 Oe). Dynamic scaling analysis of $\chi^{\prime \prime}(T, \omega)$ and $\tau(T,H)$ near $T_{g}$ leads to the critical exponents ($\beta$ = 0.36 $\pm$ 0.03, $\gamma$ = 3.5 $\pm$ 0.4, $\nu$ = 1.4 $\pm$ 0.2, $z$ = 6.6 $\pm$ 1.2, $\psi$ = 0.24 $\pm$ 0.02, and $\theta$ = 0.13 $\pm$ 0.02). The aging phenomenon is studied through the absorption $\chi^{\prime \prime}(\omega, t)$ below $T_{g}$. It obeys a $(\omega t)^{-b^{\prime \prime}}$ power-law decay with an exponent $b^{\prime \prime}\approx 0.15 - 0.2$. The rejuvenation effect is also observed under sufficiently large (temperature and magnetic-field) perturbations.Comment: 14 pages, 19 figures; to be published in Phys. Rev. B (September 1, 2003

Critical aspects of three-dimensional anisotropic spin-glass models

We study the $\pm J$ three-dimensional Ising model with a longitudinal anisotropic bond randomness on the simple cubic lattice. The random exchange interaction is applied only in the $z$ direction, whereas in the other two directions, $xy$ - planes, we consider ferromagnetic exchange. By implementing an effective parallel tempering scheme, we outline the phase diagram of the model and compare it to the corresponding isotropic one, as well as to a previously studied anisotropic (transverse) case. We present a detailed finite-size scaling analysis of the ferromagnetic - paramagnetic and spin glass - paramagnetic transition lines, and we also discuss the ferromagnetic - spin glass transition regime. We conclude that the present model shares the same universality classes with the isotropic model, but at the symmetric point has a considerably higher transition temperature from the spin-glass state to the paramagnetic phase. Our data for the ferromagnetic - spin glass transition line are supporting a forward behavior in contrast to the reentrant behavior of the isotropic model.Comment: 10 pages, 9 eps figures, 1 table, corrected symbolis

Foreign policy beliefs and support for Stephen Harper and the Conservative Party

Similar to other recent Canadian elections, foreign policy did not feature prominently in the 2011 federal election campaign. In fact, many doubt Canadian public opinion on international affairs is linked to the actions taken by recent Governments. In this paper, we examine Canadian public opinion toward a range of foreign policy issues and argue that the survey questions measure two latent dimensions —militarism and internationalism. Our survey evidence indicates the existence of an “issue public” which is prepared to endorse military action and is skeptical of human rights and overseas aid programs, and this group is far more supportive of Prime Minister Harper and the Conservative Party than other Canadians. The absence of an elite discussion, either among politicians or between media elites, about the direction of Canadian foreign policy does not prevent the Canadian voter from thinking coherently about questions pertaining to this issue domain and employing these beliefs to support or oppose political parties and their leaders

Advances in ab-initio theory of Multiferroics. Materials and mechanisms: modelling and understanding

Within the broad class of multiferroics (compounds showing a coexistence of magnetism and ferroelectricity), we focus on the subclass of "improper electronic ferroelectrics", i.e. correlated materials where electronic degrees of freedom (such as spin, charge or orbital) drive ferroelectricity. In particular, in spin-induced ferroelectrics, there is not only a {\em coexistence} of the two intriguing magnetic and dipolar orders; rather, there is such an intimate link that one drives the other, suggesting a giant magnetoelectric coupling. Via first-principles approaches based on density functional theory, we review the microscopic mechanisms at the basis of multiferroicity in several compounds, ranging from transition metal oxides to organic multiferroics (MFs) to organic-inorganic hybrids (i.e. metal-organic frameworks, MOFs)Comment: 22 pages, 9 figure

Ripples in a pond: Do social work students need to learn about terrorism?

In the face of heightened awareness of terrorism, however it is defined, the challenges for social work are legion. Social work roles may include working with the military to ensure the well-being of service-men and women and their families when bereaved or injured, as well as being prepared to support the public within the emergency context of an overt act of terrorism. This paper reviews some of the literature concerning how social work responds to confl ict and terrorism before reporting a smallscale qualitative study examining the views of social work students, on a qualifying programme in the UK, of terrorism and the need for knowledge and understanding as part of their education