1,115 research outputs found
In Vitro Evaluation Of The Abrasiveness Of A Commercial Low-abrasive Dentifrice And An Experimental Dentifrice Containing Vegetable Oil
Toothpastes usually contain detergents, humectants, water colorant, fluoride and thickeners (e.g. silica). Tooth wear has a multi-factorial etilology and the use of abrasive dentifrices is related to abrasion of dental tissues during toothbrushing. This study evaluated in vitro the abrasiveness of a commercial silica gel low-abrasive dentrifice compared to an experimental dentifrice containing vegetable (almond) oil. Distilled water served as a control group. Acrylic specimens (8 per group) were submitted to simulated toothbrushing with slurries of the commercial dentifrice experimental dentifrice, almond oil and water in an automatic brushing machine programmed to 30,000 brush strokes for each specimen which is equivalent to 2 years of manual toothbrushing. Thereafter, surface roughness (Ra) of the specimens was analyzed with a Surfcorder SE 1700 profilometer. Data were analyzed statistically by ANOVA and Tukey's test at 5% significance level. There was no statistically significant differences (p>0.05) in the surface roughness after brushing with water almond oil experimental dentifrice. The commercial dentifrice produced rougher surfaces compared to the control and abrasive free products (p<0.05). Further studies are necessary in confirm the potential benefits of using vegetable oil in toothpaste as an alternative in abrasives in an attempt to minimize the tooth wear caused by toothbrushing.72415261530Löe, H., Kleinman, D.V., (1986) Dental Plaque Control Measures and Oral Hygiene Practices, , Oxford: IRL Press;, 332pBueno, M.A.M., Toledo, S., Sallum, E.A., Nociti Junior, F.H., Influência da escovação dental orientada na redução do sangramento gengival, em áreas próximas a restauraç-tioes metálicas. (1998) Rev ABO Nac, 6, pp. 44-47Andrade Junior, A.C.C., Andrade, M.R.T.C., Machado, W.A.S., Fischer, R.G., Abrasividade de dentifrícios: Revisão de literatura. (1997) Rev Periodontia, 6, pp. 25-30Baxter, P.M., Davis, W.B., Jackson, J., Toothpaste abrasive requirements to control naturally stained pellicle (1981) J Oral Rebabil, 8, pp. 19-26Hefferren, J.J., Schemehon, B., Storek, A., Lerck, M., Li, N., Silica as a reference for laboratory dentifrice assessment methods: Multiple collaborative study (2007) J Clin Dent, 8, pp. 12-16Stookey, G., Muhler, J., Laboratory studies concerning the enamel and dentin abrasion properties of common dentifrice polishing agents (1968) J Dent Res, 47, pp. 524-532Glantz, P.O., Larsson, L.A., Surface roughness of composite resins before and after toothbrushing (1972) Acta Odont Scand, 30, pp. 335-347Prampero, A.L., Lara, E.H.G., Tastes, R.C.A., Ogasawara, M.S., Panzeri, H., (1992) Relação das escovas com dentifrícios: Estudo da interação de escovas dentais de diferentes tipos de cerdas com preparações básicas para dentifr-acicios, 40, pp. 298-302. , RGOSlop, D., Rooij, J.F., Arends, J., Abrasion of enamel. 1. An in vitro investigation (1983) Caries Res, 17, pp. 242-248Heath, J., Wilson, J., Abrasion of restorative materials by toothpaste (1976) J Oral Rehabil, 3, pp. 121-138Patrão FGD, Sinhoreti MAC, Consani S, Correr Sobrinho L, Milan FM. Avaliação in vitro da rugosidade produzida por escovas dentais e dentifríicios em resina para base de prótese. Rev Fac Odontol Univ Passo Fundo. 19983: 7-14Correr Sobrinho, L., Francisco, M.U., Consani, S., Sinhoreti, M.A.C., Consani, R.L.X., Influência da escovação na rugosidade de superfície de materiais restauradores estéticos. (2001) PGR Pós-Grad Rev Fac Odontol São Jose dos Campos, 4, pp. 47-55Lara, E.H.G., Panzeri, H., Ogasawara, M.S., Ciampo, J.O.D., Moraes, J.T., Avaliação laboratorial dos dentifrícios cornerciais. (1996) Rev ABO Nac, 4, pp. 176-180Addy, M., Goodfield, S., Harrison, A., The use of acrylic to compare the abrasivity and stain removal proprieties of toothpastes (1991) Clin Mater, 7, pp. 219-225Addy, M., Evaluation of clinical trials of agents and procedures to prevent caries and periodontal disease: Choosing products and recommending procedures (1995) Int Dent J, 45, pp. 185-196Shaw, L., al-Dlaigan, Y.H., Smith, A., Childhood asthma and dental erosion (2000) J Dent Child, 67, pp. 102-106Al-Dlaigan, Y.H., Shaw, L., Smith, A.J., Is there a relationship between asthma and dental erosion? A case control study (2002) Int J Paediatric Dent, 12, pp. 189-200Aguiar, A.A.A., Moraes Filho, F.C., A interferência do óleo vegetal na aderência da placa bacteriana dental. (1998) Rev Cienc Odontol, 1, pp. 21-25Aguiar, A.A.A., Saliba, N.A., Toothbrushing with vegetable oil: A clinical and laboratorial analysis (2004) Braz Oral Res, 18, pp. 168-173Meneghim, M.C., Pereira, A.C., Silva, F.R.B., Prevalência da cárie radicular e condiç-tiao periodontal em uma população idosa institucionalizada de Piracicaba - SP. (2002) Pesqui Odontol Bras, 16, pp. 50-56Fransson, C., Berglundh, T., Lindhe, J., The effect of age on the development of gingivitis. Clinical, microbiological and histological findings (1996) J Clin Periodontal, 23, pp. 379-385Lima FAP, Góes MF, Consani S. Avaliação in vitro da ação abrasiva de escovas dentais. Odonto. 1998;3:23-7Santos, P.H., (2000) Avaliação da porosidade interna e da rugosidade de superfície de resinas compostas para dentes posteriores submetidas à escovação, , Master's thesis, Piracicaba-SP: Piracicaba Dental School/UNICAMP;, 180pMoore, C., Addy, M., Wear of dentin in vitro by toothpaste abrasives and detergents alone and combined (2005) J Clin Periodontol, 32, pp. 1242-1246Joiner, A., Pickles, M.J., Tanner, C., Weader, E., Doyle, P., An in situ model to study the toothpaste abrasion of enamel (2004) J Clin Periodontol, 31, pp. 434-438Figueiredo, M.C., Bello, D., Avaliação comparativa entre a eficácia de uma escova alternativa e uma escova convencional na remoção de placa dent-acaria. (1999) Rev Fac Odontol Univ Passo Fundo, 4, pp. 13-2
Once again about quantum deformations of D=4 Lorentz algebra: twistings of q-deformation
This paper together with the previous one (arXiv:hep-th/0604146) presents the
detailed description of all quantum deformations of D=4 Lorentz algebra as Hopf
algebra in terms of complex and real generators. We describe here in detail two
quantum deformations of the D=4 Lorentz algebra o(3,1) obtained by twisting of
the standard q-deformation U_{q}(o(3,1)). For the first twisted q-deformation
an Abelian twist depending on Cartan generators of o(3,1) is used. The second
example of twisting provides a quantum deformation of Cremmer-Gervais type for
the Lorentz algebra. For completeness we describe also twisting of the Lorentz
algebra by standard Jordanian twist. By twist quantization techniques we obtain
for these deformations new explicit formulae for the deformed coproducts and
antipodes of the o(3,1)-generators.Comment: 17 page
Low Energy Excitations in Spin Glasses from Exact Ground States
We investigate the nature of the low-energy, large-scale excitations in the
three-dimensional Edwards-Anderson Ising spin glass with Gaussian couplings and
free boundary conditions, by studying the response of the ground state to a
coupling-dependent perturbation introduced previously. The ground states are
determined exactly for system sizes up to 12^3 spins using a branch and cut
algorithm. The data are consistent with a picture where the surface of the
excitations is not space-filling, such as the droplet or the ``TNT'' picture,
with only minimal corrections to scaling. When allowing for very large
corrections to scaling, the data are also consistent with a picture with
space-filling surfaces, such as replica symmetry breaking. The energy of the
excitations scales with their size with a small exponent \theta', which is
compatible with zero if we allow moderate corrections to scaling. We compare
the results with data for periodic boundary conditions obtained with a genetic
algorithm, and discuss the effects of different boundary conditions on
corrections to scaling. Finally, we analyze the performance of our branch and
cut algorithm, finding that it is correlated with the existence of
large-scale,low-energy excitations.Comment: 18 Revtex pages, 16 eps figures. Text significantly expanded with
more discussion of the numerical data. Fig.11 adde
PT-symmetric Solutions of Schrodinger Equation with position-dependent mass via Point Canonical Transformation
PT-symmetric solutions of Schrodinger equation are obtained for the Scarf and
generalized harmonic oscillator potentials with the position-dependent mass. A
general point canonical transformation is applied by using a free parameter.
Three different forms of mass distributions are used. A set of the energy
eigenvalues of the bound states and corresponding wave functions for target
potentials are obtained as a function of the free parameter.Comment: 13 page
Avaliação da incidência de antracnose, do desempenho e estado nutricional de variedades de mangueira, para cultivo orgânico, na região centro-norte do Estado de São Paulo.
A mudança do perfil do consumidor, aliada aos riscos da contaminação por agrotóxicos, tem levado à busca de alternativas ecologicamente apropriadas para produção de frutas. Os objetivos deste trabalho foram avaliar a incidência de antracnose, o desempenho e estado nutricional de variedades de mangueira conduzidas organicamente na região de Pindorama-SP. Foram utilizadas 17 variedades de mangueira. O experimento foi instalado em delineamento experimental em blocos completos ao acaso, com 17 tratamentos (variedades) e seis repetições. Foi avaliada a severidade de antracnose nas folhas, através de uma escala diagramática, atribuindo-se notas aos sintomas. Foram avaliados o crescimento e o desenvolvimento (altura da planta, perímetro do tronco e da copa) e o estado nutricional, mediante análise foliar, das diferentes variedades utilizadas. Através dos resultados obtidos, podem-se considerar como muito suscetíveis à antracnose as variedades Bourbon, Rocha e Rosa; e resistentes, as variedades IAC 111, Alfa, Beta e Parvin; as variedades de manga apresentaram o mesmo padrão de crescimento; as maiores alturas da planta corresponderam aos maiores diâmetros do tronco e da copa; a variedade Parvin apresentou o melhor desempenho dentre as variedades estudadas, com relação à resistência à antracnose, altura e diâmetro do caule e da copa, podendo ser recomendada ao cultivo orgânico. As variedades Omega e Alfa também apresentaram bom crescimento, podendo ser indicadas para esse cultivo, pelo menos nessa fase inicial; as variedades Surpresa e Rosa não apresentaram bom desempenho, no campo, em relação às demais, não devendo ser recomendadas para o cultivo orgânico, principalmente a variedade Rosa, bastante suscetível à antracnose. As concentrações de N, P e K foram elevadas na fase vegetativa das plantas, comparadas à baixa concentração de Ca; houve carência de Boro em todas as variedades estudadas. A manga Rosa, provavelmente, sofreu toxicidade ao excesso de manganês, ocasionando diminuição em seu desenvolvimento
Magnetic Field Amplification in Galaxy Clusters and its Simulation
We review the present theoretical and numerical understanding of magnetic
field amplification in cosmic large-scale structure, on length scales of galaxy
clusters and beyond. Structure formation drives compression and turbulence,
which amplify tiny magnetic seed fields to the microGauss values that are
observed in the intracluster medium. This process is intimately connected to
the properties of turbulence and the microphysics of the intra-cluster medium.
Additional roles are played by merger induced shocks that sweep through the
intra-cluster medium and motions induced by sloshing cool cores. The accurate
simulation of magnetic field amplification in clusters still poses a serious
challenge for simulations of cosmological structure formation. We review the
current literature on cosmological simulations that include magnetic fields and
outline theoretical as well as numerical challenges.Comment: 60 pages, 19 Figure
Measurement of the branching fraction
The branching fraction is measured in a data sample
corresponding to 0.41 of integrated luminosity collected with the LHCb
detector at the LHC. This channel is sensitive to the penguin contributions
affecting the sin2 measurement from The
time-integrated branching fraction is measured to be . This is the most precise measurement to
date
Model-independent search for CP violation in D0→K−K+π−π+ and D0→π−π+π+π− decays
A search for CP violation in the phase-space structures of D0 and View the MathML source decays to the final states K−K+π−π+ and π−π+π+π− is presented. The search is carried out with a data set corresponding to an integrated luminosity of 1.0 fb−1 collected in 2011 by the LHCb experiment in pp collisions at a centre-of-mass energy of 7 TeV. For the K−K+π−π+ final state, the four-body phase space is divided into 32 bins, each bin with approximately 1800 decays. The p-value under the hypothesis of no CP violation is 9.1%, and in no bin is a CP asymmetry greater than 6.5% observed. The phase space of the π−π+π+π− final state is partitioned into 128 bins, each bin with approximately 2500 decays. The p-value under the hypothesis of no CP violation is 41%, and in no bin is a CP asymmetry greater than 5.5% observed. All results are consistent with the hypothesis of no CP violation at the current sensitivity
Measurement of the CP-violating phase \phi s in Bs->J/\psi\pi+\pi- decays
Measurement of the mixing-induced CP-violating phase phi_s in Bs decays is of
prime importance in probing new physics. Here 7421 +/- 105 signal events from
the dominantly CP-odd final state J/\psi pi+ pi- are selected in 1/fb of pp
collision data collected at sqrt{s} = 7 TeV with the LHCb detector. A
time-dependent fit to the data yields a value of
phi_s=-0.019^{+0.173+0.004}_{-0.174-0.003} rad, consistent with the Standard
Model expectation. No evidence of direct CP violation is found.Comment: 15 pages, 10 figures; minor revisions on May 23, 201
Measurement of charged particle multiplicities in collisions at TeV in the forward region
The charged particle production in proton-proton collisions is studied with
the LHCb detector at a centre-of-mass energy of TeV in different
intervals of pseudorapidity . The charged particles are reconstructed
close to the interaction region in the vertex detector, which provides high
reconstruction efficiency in the ranges and
. The data were taken with a minimum bias trigger, only requiring
one or more reconstructed tracks in the vertex detector. By selecting an event
sample with at least one track with a transverse momentum greater than 1 GeV/c
a hard QCD subsample is investigated. Several event generators are compared
with the data; none are able to describe fully the multiplicity distributions
or the charged particle density distribution as a function of . In
general, the models underestimate the charged particle production
- …