307 research outputs found
Multilateral climate finance coordination: politics and depoliticization in practice
The governance of public climate finance for mitigation and adaptation in developing countries is fragmented on both the international and national levels, with a high diversity of actors with overlapping mandates, preferences, and areas of expertise. In the absence of one unifying actor or institution, coordination among actors has emerged as a response to this fragmentation. In this article, we study the coordination efforts of the two most important multilateral climate funds, the Climate Investment Funds (CIF) and the Green Climate Fund (GCF), on the global level as well as within two recipient countries, Kenya and Zambia. The CIF and the GCF are anchored within the World Bank and the United Nations Framework Convention on Climate Change, respectively, and represent two diverging perspectives on climate finance. We find that on both levels, coordination was depoliticized by treating it as a technical exercise, rendering invisible the political divergences among actors. The implications of this depoliticization are that both funds coordinate mainly with actors with similar preferences, and consequently, coordination did not achieve its objectives. The article contributes to the literatures on coordination, climate finance, and environmental governance by showing how a response to the fragmentation of climate governance did not overcome political fault lines but rather reinforced them
Enzyme prodrug therapy achieves site-specific, personalized physiological responses to the locally produced nitric oxide
Nitric oxide (NO) is a highly potent but short-lived endogenous radical with a wide spectrum of physiological activities. In this work, we developed an enzymatic approach to the site-specific synthesis of NO mediated by biocatalytic surface coatings. Multilayered polyelectrolyte films were optimized as host compartments for the immobilized β-galactosidase (β-Gal) enzyme through a screen of eight polycations and eight polyanions. The lead composition was used to achieve localized production of NO through the addition of β-Gal–NONOate, a prodrug that releases NO following enzymatic bioconversion. The resulting coatings afforded physiologically relevant flux of NO matching that of the healthy human endothelium. The antiproliferative effect due to the synthesized NO in cell culture was site-specific: within a multiwell dish with freely shared media and nutrients, a 10-fold inhibition of cell growth was achieved on top of the biocatalytic coatings compared to the immediately adjacent enzyme-free microwells. The physiological effect of NO produced via the enzyme prodrug therapy was validated ex vivo in isolated arteries through the measurement of vasodilation. Biocatalytic coatings were deposited on wires produced using alloys used in clinical practice and successfully mediated a NONOate concentration-dependent vasodilation in the small arteries of rats. The results of this study present an exciting opportunity to manufacture implantable biomaterials with physiological responses controlled to the desired level for personalized treatment
A Model for the Analysis of Caries Occurrence in Primary Molar Tooth Surfaces
Recently methods of caries quantification in the primary dentition have moved away from summary ‘whole mouth’ measures at the individual level to methods based on generalised linear modelling (GLM) approaches or survival analysis approaches. However, GLM approaches based on logistic transformation fail to take into account the time-dependent process of tooth/surface survival to caries. There may also be practical difficulties associated with casting parametric survival-based approaches in a complex multilevel hierarchy and the selection of an optimal survival distribution, while non-parametric survival methods are not generally suitable for the assessment of supplementary information recorded on study participants. In the current investigation, a hybrid semi-parametric approach comprising elements of survival-based and GLM methodologies suitable for modelling of caries occurrence within fixed time periods is assessed, using an illustrative multilevel data set of caries occurrence in primary molars from a cohort study, with clustering of data assumed to occur at surface and tooth levels. Inferences of parameter significance were found to be consistent with previous parametric survival-based analyses of the same data set, with gender, socio-economic status, fluoridation status, tooth location, surface type and fluoridation status-surface type interaction significantly associated with caries occurrence. The appropriateness of the hierarchical structure facilitated by the hybrid approach was also confirmed. Hence the hybrid approach is proposed as a more appropriate alternative to primary caries modelling than non-parametric survival methods or other GLM-based models, and as a practical alternative to more rigorous survival-based methods unlikely to be fully accessible to most researchers
of Cariogenic Biofilms What Constitutes Dental Caries? Histopathology of Carious Enamel and Dentin Related to the Action
A comparative study of ultrasonic direct contact, immersion, and layer resonance methods for assessment of enamel thickness in teeth
Wear of dental enamel is a growing problem, but is clinically difficult to diagnose and monitor. An accurate and easy-to-use non-destructive method for the measurement of enamel thickness would be useful for early diagnosis of enamel loss and for monitoring progression. Ultrasound has been identified by several researchers as a potential tool suitable for enamel thickness measurement. However, in vitro studies have shown that while the method is feasible, it suffers from wide variability. The methods proposed to date rely on the measurement of the time of flight of an ultrasonic pulse through the enamel layer. This requires the operator to locate the enamel-dentine junction. In this work, three methods are evaluated to try to reduce this variability and to investigate some practicalities of the approach. Time-of-flight methods using both contact and immersion transducers were used. Immersion transducers gave the most accurate results, within 10-15 per cent of values deduced from tooth sections, but would be harder to arrange for in vivo measurements. Preliminary studies have also shown that it is possible to achieve a resonance in the enamel layer and to measure thickness that way. While this approach needs further experimental refinement, it has the potential to be used for much thinner enamel layer thicknesses
Factors Associated to Endemic Dental Fluorosis in Brazilian Rural Communities
The present paper examines the relationship between hydrochemical characteristics and endemic dental fluorosis, controlling for variables with information on an individual level. An epidemiological survey was carried out in seven rural communities in two municipalities in the state of Minas Gerais, Brazil. The Thystrup & Fejerskov index was employed by a single examiner for the diagnosis of dental fluorosis. A sampling campaign of deep groundwater in the rural communities of interest was carried out concomitantly to the epidemiological survey for the determination of physiochemical parameters. Multilevel modeling of 276 individuals from seven rural communities was achieved using the non-linear logit link function. Parameters were estimated using the restricted maximum likelihood method. Analysis was carried out considering two response variables: presence (TF 1 to 9) or absence (TF = 0) of any degree of dental fluorosis; and presence (TF ≥ 5—with loss of enamel structure) or absence of severe dental fluorosis (TF ≤ 4—with no loss of enamel structure). Hydrogeological analyses revealed that dental fluorosis is influenced by the concentration of fluoride (OR = 2.59 CI95% 1.07–6.27; p = 0.073) and bicarbonate (OR = 1.02 CI95% 1.01–1.03; p = 0.060) in the water of deep wells. No other variable was associated with this prevalence (p > 0.05). More severe dental fluorosis (TF ≥ 5) was only associated with age group (p < 0.05). No other variable was associated to the severe dental fluorosis (p > 0.05). Dental fluorosis was found to be highly prevalent and severe. A chemical element besides fluoride was found to be associated (p > 0.05) to the prevalence of dental fluorosis, although this last finding should be interpreted with caution due to its p value
The effect of fluoride on enamel and dentin formation in the uremic rat incisor
Renal impairment in children is associated with
tooth defects that include enamel pitting and hypoplasia.
However, the specific effects of uremia on tooth formation
are not known. In this study, we used rat mandibular incisors,
which continuously erupt and contain all stages of tooth
formation, to characterize the effects of uremia on tooth
formation. We also tested the hypothesis that uremia
aggravates the fluoride (F)-induced changes in developing
teeth. Rats were subjected to a two-stage 5/6 nephrectomy or
sham operation and then exposed to 0 (control) or 50 ppm
NaF in drinking water for 14 days. The effects of these
treatments on food intake, body growth rate, and biochemical
serum parameters for renal function and calcium
metabolism were monitored. Nephrectomy reduced food
intake and weight gain. Intake of F by nephrectomized rats
increased plasma F levels twofold and further decreased food
intake and body weight gain. Uremia affected formation of
dentin and enamel and was more extensive than the effect of
F alone. Uremia also significantly increased predentin width
and induced deposition of large amounts of osteodentin-like
matrix-containing cells in the pulp chamber. In enamel
formation, the cells most sensitive to uremia were the
transitional-stage ameloblasts. These data demonstrate that
intake of F by rats with reduced renal function impairs F
clearance from the plasma and aggravates the already
negative effects of uremia on incisor tooth development
Effect of pH of amine fluoride containing toothpastes on enamel remineralization in vitro
<p>Abstract</p> <p>Background</p> <p>One of the important factors of the demineralization and remineralization equilibrium of enamel is the pH of the surrounding solutions. Effort has been laid in the formulation of different fluoride compounds and the fluoride content in toothpastes but much less is known about the influence of the pH of the toothpastes on their effectiveness. It was therefore the aim of this study to investigate the influence of different pH levels on enamel remineralization in an in vitro experiment using polarization light microscopy and EDX quantitative element analysis.</p> <p>Methods</p> <p>A 5 × 5 mm window on the enamel surface of 40 caries free extracted human premolars was demineralized in a hydroxyethylcellulose solution at pH 4.8. The teeth were divided into 8 groups and the lower half of the window was covered with varnish serving as control. Each group was then immersed in toothpaste slurry containing amine fluoride (1400 ppm) at pH 4.1, 4.5, 5.1 and 6.9 or control toothpaste slurry without fluoride at pH 4.3, 4.7, 5.3 and 7.0. Serial sections were cut through the lesions and investigated with polarization light microscopy and quantitative EDX element analysis.</p> <p>Results</p> <p>The PLM results showed a decreased porous volume of the body of the lesion after incubation with fluoridated toothpaste at pH 4.53 and 5.16. No differences between the experimental window and the control window were found in the other groups. The quantitative element analysis showed no differences in the element content of any of the groups.</p> <p>Conclusion</p> <p>From the results it can be concluded that slightly acidified fluoridated dentifrices may have a certain positive effect on enamel remineralization.</p
Linear enamel hypoplasia and historical change in a central Australian community
The document attached has been archived with permission from the Australian Dental Association. An external link to the publisher’s copy is included.Background: The current study extends the use of linear enamel hypoplasia (LEH) to examine the historical changes in living conditions encountered by Aboriginal people at Yuendumu who were born between 1890 and 1960. LEH provides health information beyond written records and gives insight into the relationship between individual health and living conditions during initial and ongoing contact with Europeans. Materials and Methods: The dental casts of 446 people, collected as part of the University of Adelaide longitudinal study of growth and development, were recorded for the presence of hypoplastic defects. Defects were recorded according to the Development Defects of the Enamel (DDE) standards and assigned to developmental units based on their crown position. Results: The frequency of LEH on the permanent dentitions increased five-fold from the 1890-1929 birth cohort to the 1955-1960 cohort. LEH also affected earlier developing enamel units. Deciduous defects did not show a strong temporal trend but overall prevalence was comparable to other disadvantaged groups. Conclusion: The changes in permanent LEH frequency and age distribution correspond to altered living conditions with the worst hypoplasia recorded after settlement of Aboriginal people at Yuendumu. Prior to that period LEH was comparable to precontact Australian populations indicating that resettlement had a dramatic impact on childhood morbidity.J Littleton and GC Townsen
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