1,015 research outputs found
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, non-Abelian anyons
We study an exactly solvable model of 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: 1â 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: CuCoCl-FeCl graphite bi-intercalation compound
Static and dynamic behavior of short-range Ising-spin glass
CuCoCl-FeCl graphite bi-intercalation compounds
(GBIC) has been studied with SQUID DC and AC magnetic susceptibility. The
dependence of the zero-field relaxation time above a spin-freezing
temperature (= 3.92 0.11 K) is well described by critical slowing
down. The absorption below decreases with
increasing angular frequency , which is in contrast to the case of 3D
Ising spin glass. The dynamic freezing temperature at which
dd, is determined as a function of
frequency (0.01 Hz 1 kHz) and magnetic field (0 5 kOe). The dynamic scaling analysis of the relaxation time
defined as at suggests the absence of
SG phase in the presence of (at least above 100 Oe). Dynamic scaling
analysis of and near
leads to the critical exponents ( = 0.36 0.03, = 3.5
0.4, = 1.4 0.2, = 6.6 1.2, = 0.24
0.02, and = 0.13 0.02). The aging phenomenon is studied through
the absorption below . It obeys a
power-law decay with an exponent . 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 three-dimensional Ising model with a longitudinal
anisotropic bond randomness on the simple cubic lattice. The random exchange
interaction is applied only in the direction, whereas in the other two
directions, - 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 âmilitarism and internationalism. Our survey evidence indicates the existence of an âissue publicâ 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
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