777 research outputs found
Does psychological stress mediate social deprivation in tooth loss?
No full textCopyright © 2007 International and American Associations for Dental ResearchIt is unclear which theoretical dimension of psychological stress affects health status. We hypothesized that both distress and coping mediate the relationship between socio-economic position and tooth loss. Cross-sectional data from 2915 middle-aged adults evaluated retention of < 20 teeth, behaviors, psychological stress, and sociodemographic characteristics. Principal components analysis of the Perceived Stress Scale (PSS) extracted ’distress’ (a = 0.85) and ’coping’ (a =0.83) factors, consistent with theory. Hierarchical entry of explanatory variables into age- and sex-adjusted logistic regression models estimated odds ratios (OR) and 95% confidence intervals [95% CI] for retention of < 20 teeth. Analysis of the separate contributions of distress and coping revealed a significant main effect of coping (OR = 0.7 [95% CI = 0.7–0.8]), but no effect for distress (OR = 1.0 [95% CI = 0.9–1.1]) or for the interaction of coping and distress. Behavior and psychological stress only modestly attenuated socio-economic inequality in retention of < 20 teeth, providing evidence to support a mediating role of coping.A.E. Sanders, G.D. Slade, G. Turrell, A.J. Spencer, and W. Marcene
DS_10.1177_0022034518774331 – Supplemental material for Water Fluoridation and Dental Caries in U.S. Children and Adolescents
No full textSupplemental material, DS_10.1177_0022034518774331 for Water Fluoridation and Dental Caries in U.S. Children and Adolescents by G.D. Slade, W.B. Grider, W.R. Maas and A.E. Sanders in Journal of Dental Research</p
Affluent neighborhoods reduce excess risk of tooth loss among the poor
No full textThe effect of neighborhood on health may vary according to the characteristics of the residents. We tested the hypothesis that, in affluent neighborhoods, low-income adults retain more teeth than their income-equivalent peers in poor neighborhoods. In 2003, the Adelaide Small Area Dental Study collected sociodemographic and tooth retention information from 2860 adults in 60 neighborhoods. Neighborhood socio-economic position was a census-based composite measure. Using multilevel modelling, we fitted a series of two-level random intercept variance component models. Findings revealed significant main effects for individual and neighborhood predictors and a significant interaction between neighborhood disadvantage and low income. In affluent areas, disparities in tooth retention were negligible, but in poor neighborhoods, substantial variation in tooth retention between individuals was found based on their level of income. Low-income adults appeared to benefit from living in affluent areas, while wealthier adults living in poor neighborhoods did not lose their oral health advantage.A.E. Sanders, G. Turrell and G.D. Slad
O impacto da doença periodontal na qualidade de vida
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Engenharia de Produção
Access to dental care among adults with physical and intellectual disabilities: residence factors
No full text© 2009 Australian Dental AssociationBackgroundThere is limited information about access and barriers to dental care among adults with disabilities.MethodsA mailed questionnaire survey of carers of 18-44-year-old South Australians with physical and intellectual disabilities (care recipients; n = 485) in family homes, community housing and institutions. Bivariate associations were tested using chi-square tests. Odds ratios (ORs) and 95 per cent confidence intervals (CI) were estimated for irregular dental visits (IDV).ResultsCarers from family homes and community housing were more likely to report problems in obtaining dental care than those at institutions (p ConclusionsCare recipients in institutions and community housing had better access to dental care than those at family homes. The shortage of dentists in SND and treatment costs needs to be addressed.A Pradhan, G.D. Slade, A.J. Spence
Trend of income-related inequality of child oral health in Australia
No full textIt is important that we monitor socio-economic inequality in health. Inequality in child oral health has been expected to widen because of widening socio-economic inequality. This study aimed to evaluate trends in income-related inequality in caries experience of Australian children. Cross-sectional studies in 1992/93 and 2002/03 collected data on deciduous caries experience of 5- to 10-year-olds and permanent caries experience of 6- to 12-year-olds. Household composition and income was used to calculate quartiles of equivalized income. Slope Index of Inequality (SII), Concentration Index (CI), and regression-based rate ratios were used to quantify income-related inequality and to evaluate trends. Income-related inequality in caries experience was evident regardless of time and dentition. The three indicators of inequality indicate a significant increase in income-related inequality in child deciduous caries experience during the decade. The income inequality in permanent caries experience did not change significantly. Income inequalities increased in deciduous teeth, but not in permanent teeth, among Australian children.L.G. Do, A.J. Spencer, G.D. Slade, D.H. Ha, K.F. Roberts-Thomson and P. Li
High pressure behaviour of AIP04-5 in penetrating/ non penetrating pressure medium
No full textAluminophosphate are objects of a growing research interest due to their potential technologieal and industriaI applications [e.g 1,2]. Their large channels serve as ideaI host for organie compounds and small polymers. Among those, AIP0-5 is a synthetic zeolite characterized by an open-framework of (P,AI)O4 tetrahedra. The tetrahedra are connected to form six-and twelve-membered rings, in such a way that a large channel (0~7.3À), parallel to the [001] direction, occurs. Klap et al. [3] underlines that every crystal of AIP0-5 is built up by three different microdomains, in which the positions of the framework oxygen atoms are slightly different; the main effect of the structural disorder is the very large anisotropie displacement parameters of the framework oxygens. We performed two in situ single-crystal synchrotron X-ray diffraction experiments using both penetrating (methanol:ethanol:H20 mix, m:e:w) and non-penetrating (silicon oil) pressure media [4]. The structure refinements showed that: 1) for compression in m:e:w mix, H20 molecules are absorbed at low-P regime, forming a H20-network by H-bonding interaction; 2) the elastic parameters of the super-hydrated AIP04 5 are different if compared to the one compressed in silicon oil; 3) the structural deformation mechanisms of super-hydrated and regular AIP04 -5 are different; 4) evidence of a incommensurately modulated structure occur (according to [3]), and there is an evolution of the non-Bragg reflections with pressure.
The author acknowledges the ltalian Ministry of Education, MIUR-Project: "Futuro in Ricerca 2012 -ImPACT-RBFR12CLQD".
[lJ Tang Z.K. et al. Applied Physies Letters 1998; 73, 2287-2289.
[2] Yang W.S. et al. Microporous and mesoporous materials 20i6; 219,87-92. [3J Klap G.J. et al. Mieroporous and mesoporous materials 2000; 38,403-412. [4J Gatta, G.D. Mieroporous and Mesoporous Material 2010; 128, 78-84
F.C. Hawthorne, Landmark papers : structure topology
No full textIn this second volume of the Mineralogical Society’s ‘Landmark’ series, Prof. Frank Hawthorne has selected a number of key papers, some of which are true milestones of mineralogy and crystallography, showing the acceleration of research and the increase in knowledge in the field of crystal-chemistry. The papers follow in chronological sequence, allowing the reader to see how crystallography and, particularly, mineralogy have evolved during the last 80 years. He has chosen the papers on the basis of three related aspects: (a) the nature of chemical bonds, and (b) their relation to bond topology, leading to (c) the prediction of bond topologies and their hierarchical organization. His commentaries on the selected papers provided a coherent narrative thread running through the volume. In the first chapter ‘Bond topology and Minerals’, Hawthorne reviews the long history of the mineralogy and crystallography, reporting the evolution of the knowledge and the experimental findings in the last 2,000 years. The author introduces the mathematical concept of topology and how to use this tool for the description of the structural configuration in crystals. In addition, he discusses the motivation of mineralogists for understanding and developing principles of bond topology. In chapter 2, two milestone papers by Linus Pauling (both published in 1929) on the structure of complex ionic crystals are reported and enriched with comments. Chapter 3 is devoted to a further milestone paper for mineralogy written by W.L. Bragg (1930), on the structure classification of the silicate minerals, the isomorphous replacement in silicates and on the application of the Pauling’s rules to this class of minerals. In Chapter 4, we jump to the 1970s with the paper of P.B. Moore (1970) on the stereoisomerism among octahedral and tetrahedral chains. Moore based his study not on a specific mineral structure, but examined the different ways in which polyhedra could link via vertices to form chains. He defines the concept of ‘‘structural hierarchy’’ as a general scheme that ties together a certain number of arrangements. An extension of the structural analysis of Moore is found in chapter 6, which is devoted to his systematic study of edge-sharing clusters, deriving the possible arrangements based solely on topological and geometrical principles according to the notions of energy minima and stability (Moore 1974). Chapter 5 deals with the paper by Brown and Shannon (1973), on the empirical bond-valence/ bond-length curves for oxides. A further refinement of the Brown and Shannon approach, into a comprehensive theory that addresses many aspects of the chemical bonding, was developed by Brown (1981), and is presented in chapter 8. Bond-valence analysis of inorganic crystal structures is an essential check on the validity of any structure determination. In his commentary on chapter 8, Hawthorne outlines the critical points introduced by Brown in the bond-valence theory, with interesting application in mineralogy, and presents the bond-valence theory as a molecular orbital theory and as an ionic theory. Chapter 7 is devoted to the paper by L.S. Dent Glasser (1979) on non-existent silicates, emphasizing that the observed arrangements in silicates represent only a small fraction of those topologically possible. Chapter 9 deals with the paper of Hawthorne (1983) on the graphical enumeration of polyhedral clusters. The author developed a ‘‘structural hierarchy’’ hypothesis which has an energetic basis and relates to paragenetic sequences. An example is Bowen’s reaction series shown as a function of the polymerization characteristic of the structure involved. A related topic is covered in chapter 10, which discusses the energetic content of bond topology with reference to the paper by Burdett et al. (1984). The last paper of this collection constituting chapter 11 is devoted to the role of OH and H2O in oxide and oxysalt minerals, based on Hawthorne (1992). The author analysed the roleplayed by (OH) , (H2O)0, (H3O)+ and (H5O2)2+ in controlling bonding topology, topological dimensionality and the role of H2O as a bond-valence transformer, which bears on the, often highly selective, uptake of interstitial cations by environmentally significant minerals. Chapter 12 is the coda, focusing on the prediction of bond topology and of the stoichiometry of stable compounds in a given chemical system. I think that the re-publication of these landmark papers, accompanied by the commentaries of Prof. Hawthorne, will be useful not only for undergraduate or PhD students, but for all structural mineralogists. This collection provides valuable insights into the evolution of structural mineralogy and its wider application to the petrology. As several of the milestone papers collected in this book are published in German journals (Zeitschrift fu ̈r Kristallographie, Neues Jahrbuch fu ̈r Mineralogie Monatshefte), I did a little inquiry and I found that these journals are often not readily available in departmental libraries, and so this is another good reason to have this book in your own library. In conclusion, I warmly recommend this volume to all mineralogists and to Earth sciences libraries.
G. DIEGO GATT
Ultra-fast escape of a deformable jet-propelled body
No full textIn this work a cephalopod-like deformable body that fills an internal cavity with fluid and expels it to propel an escape manoeuvre, while undergoing a drastic external shape change through shrinking, is shown to employ viscous as well as mainly inviscid hydrodynamic mechanisms to power an impressively fast start. First, we show that recovery of added-mass energy enables a shrinking rocket in a dense inviscid flow to achieve greater escape speed than an identical rocket in a vacuum. Next, we extend the shrinking body results of Weymouth & Triantafyllou (J. Fluid Mech., vol. 702, 2012, pp. 470–487) to three-dimensional bodies and show that three hydrodynamic mechanisms must be combined to achieve rapid escape performance in a viscous fluid: added-mass energy recovery; flow separation elimination; and an optimized energy storage and recovery. In particular, we show that the mechanism of separation elimination achieved through rapid body shrinking, coordinated with the mechanism of recovering the initially imparted added-mass energy, is critical to achieving a high escape speed. Hence a flexible, collapsing body can be vastly superior to a rigid-shell jet-propelled body
The paradox of better subjective oral health in older age
No full textWe analyzed data from the 2004-06 Australian National Survey of Adult Oral Health to investigate the paradoxical relationship of better subjective oral health in older adults compared with young or middle-aged adults. In interviews with 14,092 adults, prevalence of problems with eating or appearance was not significantly associated with age among dentate people with no denture(s). In contrast, among dentate denture-wearers, prevalence ranged from 18.7% in ≥ 65-year-olds to 46.7% in 25- to 34-year-olds (p < 0.01). Dentate interviewees (n = 3,724) underwent oral epidemiological examinations and completed the 14-item Oral Health Impact Profile (OHIP-14) questionnaire, evaluating adverse impacts of oral conditions. In multivariable analysis, mean OHIP-14 scores were only weakly associated with age among people who had none of 5 clinical conditions [≥ 5 missing teeth, denture(s), untreated decay, moderate/severe periodontitis, toothache]. However, for people with ≥ 2 clinical conditions, there was a three-fold, inverse association between age and mean OHIP-14 scores (p < 0.01). The findings show that experience of oral disease is more deleterious to subjective oral health when it occurs early in adulthood than when it occurs in old age, a pattern that likely reflects high expectations of young generations and, conversely, great resilience in Australia’s oldest generation.G.D. Slade and A.E. Sander
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