1,050 research outputs found

    Localised enamel hypoplasia of human deciduous canines: genotype or environment?

    Get PDF
    The document attached has been archived with permission from the Australian Dental Association (9th Jan 2008). An external link to the publisher’s copy is included.A discrete area of defective enamel formation that appears on the labial surface of the crowns of deciduous canine teeth has been described in both recent and prehistoric human population, with reported frequencies varying from 1 to 45 per cent. Suggestions about the aetiology of this localized hypoplasia range from genotypic factors to environmental conditions and systemic effects. The major aims of this study were to describe the frequency of occurrence and pattern of expression of the lesion in Australian Aboriginal and Caucasian ethnic groups, and to clarify the role of genetic factors by examining a sample of twins. The study sample consisted of dental casts of 181 pairs of Australian Caucasian twins, 215 Aborigines and 122 Caucasian singletons, together with 253 extracted deciduous canines. Examination of dental casts and extracted teeth was undertaken under 2X magnification with emphasis being placed upon location and expression of the lesion. The defect was observed in 49 per cent of twins and 44 per cent of Aborigines, but only 36 per cent of singletons. The percentages of affected teeth in each group were: 18 per cent in twins, 17 per cent in Aborigines and 13 per cent in Caucasians. A significant proportion of the defects occurred on the mesial aspect of the labial surface, in the middle area incisocervically, with the majority in the lower jaw. Anumber of significant differences in frequency were observed between groups, sexes, arches and sides. The results confirm some of the findings of previous studies, but also suggest that none of environmental, genetic or systemic factors can be ruled out as being involved in aetiology of the defect. The higher incidence of the lesion occurring on the mesial aspect of the labial surface is suggestive of physical trauma. Also, the vulnerability of the prominent developing mandibular canine, with its thin or missing labial covering of bone, would be expected to lead to higher prevalence of the lesion in the lower jaw. Although not definitive, the results of concordance analyses in twins were suggestive of a possible genetic predisposition in the formation of the lesion. Further research with a greater clinical orientation and emphasis on determing specific aetiological factors within any given environment in different ethnic groups may provide better insight into the ambiguous aetiology of the hypoplastic enamel defect.Sue Taji, Toby Hughes, Jim Rogers, Grant Townsen

    A study of primary dental enamel from preterm and full-term children using light and scanning electron microscopy

    Get PDF
    Purpose: The aim of this study was to examine the enamel thickness of the maxillary primary incisors of preterm children with very low birth weight (< 1,500 g) compared to full-term children with normal birth weight. Methods: A total of 90 exfoliated maxillary primary central incisors were investigated using light microscopy and scanning electron microscopy (SEM). Three serial buccolingual ground sections of each tooth were examined under light microscopy, and maximum dimensions of the prenatally and postnatally formed enamel were measured. Results: The enamel of preterm teeth was approximately 20% thinner than that for fullterm teeth. Most of the reduction was observed in the prenatally formed enamel. This was 5 to 13 times thinner than that for full-term children (P < .001). The catch-up thickness of postnatally formed enamel did not compensate fully for the decrease in prenatal enamel (P < .001). Although none of the teeth used in this study had enamel defects visible to the naked eye, 52% of preterm teeth showed enamel hypoplasia under SEM, compared with only 16% found on full-term teeth (P < .001). These defects were present as pits or irregular, shallow areas of missing enamel. Conclusions: Preterm primary dental enamel is abnormal in surface quality, and is significantly thinner compared to full-term enamel. The thinner enamel is due mainly to reduced prenatal growth and results in smaller dimensions of the primary dentition

    Perceptual sensitivity is modulated by what others can see

    Get PDF
    Previous work has established that social cues such as the direction of others’ gaze or their perspective on a scene may influence one’s own perceptual judgments. However, up until now it has remained unclear whether such influences are exerted at a perceptual or decisional locus, as most previous studies have used response times as their primary dependent measure. Here, we asked whether perceptual sensitivity is also dependent on social cognition. To test this hypothesis, we asked participants to evaluate whether low-contrast Gabor patterns embedded in noise were visible from either their own or an avatar’s perspective. Across three experiments, we found that observers’ detection performance was increased if an avatar also shared perception of the stimulus location. By leveraging signal detection modelling, we show that this effect is driven by a change in perceptual sensitivity (dâ€Č), independent of decisional or response interference. Furthermore, by Bblindfolding^ the avatar, we show that the boosting effect of shared perception on detection sensitivity is only obtained when the participant believes the avatar can also see the stimulus, ruling out an influence of low-level directional cues. We interpret these results within a framework in which the avatar’s perspective boosts top-down spatial attention by prioritising particular spatial locations at which perception is shared. In summary, we reveal that perceptual sensitivity is modulated by the perspective of others

    High tea consumption diminishes salivary 17beta-estradiol concetration in Polish women

    Get PDF
    ArtykuƂ recenzowany / peer-reviewed articleWe hypothesized that among reproductive-age women consuming large quantities of tea, the production of estradiol would be suppressed. It has been shown that catechins and theaflavines, the major constituents of tea, inhibit aromatase, an enzyme which catalyses the conversion of androgens to estrogens. Our study included Polish women living in urban (N=61) and rural (N=48) areas. Women collected daily saliva samples for one complete menstrual cycle and filled out dietary questionnaires. Saliva samples were analyzed by radioimmunoassay for concentration of 17-ÎČ estradiol (E2). Women with high (above the median) average daily consumption of black tea had reduced levels of salivary E2, in comparison with women who drank less black tea (below median). This effect was observed within the whole study group, as well as separately within urban (p = 0.0006) and rural (p = 0.013) groups. High intake of the sum of subclasses of tea catechins and epigallocatechin gallate, assessed using the USDA database [http://www.nal.usda.gov], was also associated with lower concentrations of E2 within all women (p = 0.01 and p = 0.0001, respectively) and within the urban group (p = 0.0001 and p = 0.004, respectively). Similar relationships were observed between the sum of subclasses of theaflavines and thearubigines and E2 levels for the whole group (p = 0.002) and for urban women (p = 0.02). Women with high consumption of tea had lower levels of E2 concentration throughout the entire menstrual cycle. These results may have implications for reducing hormone-related cancer risk by a relatively easy dietary intervention.the State Committee for Scientific Research, Warsaw, Poland, project No. 3 P05E 016 25 and 6 P05D 112 20, the Radcliffe Institute of Advanced Study, Harvard University and the Norwegian Cancer Society

    Benefits for public healthcare buildings towards Net Zero Energy Buildings (NZEBs): initial reviews

    Get PDF
    NZEBs concept has received incrementing attention especially since European Union Parliament are progressively moving towards regulation in which all new buildings to be “nearly Zero-Energy” Buildings by 2020. Even though this concept delivers promising benefits, previous studies found that the benefit of NZEB is still in vague to the Malaysian construction industry, mostly for healthcare buildings. The NZEBs concept implementation is critical in healthcare building as it seen as a key part of the needed transition towards sustainable development. This paper aims to define benefits of NZEBs practices through initial investigation among architects. Several existing energies works of literature and pilot studies by using semi-structured interviews were conducted. The findings divulge that, although the term ‘NZEBs design strategies’ is not being used largely across construction industry in Malaysia, some sustainable practices related to the design stage of construction has been implemented. The findings are also promising in growing awareness, practices and implementation of NZEBs design strategies by the practitioner in Malaysia. It is foreseen that the paper will provide a straightforward knowledge for future research in NZEBs design strategies practices for healthcare buildings construction in Malaysia

    Treatment of landfill leachate using ASBR combined with zeolite adsorption technology

    Get PDF
    Sanitary landfilling is the most common way to dispose solid urban waste; however, improper landfill management may pose serious environmental threats through discharge of high strength polluted wastewater also known as leachate. The treatment of landfill leachate to fully reduce the negative impact on the environment, is nowadays a challenge. In this study, an aerobic sequencing batch reactor (ASBR) was proposed for the treatment of locally obtained real landfill leachate with initial ammoniacal nitrogen and chemical oxygen demand (COD) concentration of 1800 and 3200 mg/L, respectively. ASBR could remove 65 % of ammoniacal nitrogen and 30 % of COD during seven days of treatment time. Thereafter, an effective adsorbent, i.e., zeolite was used as a secondary treatment step for polishing the ammoniacal nitrogen and COD content that is present in leachate. The results obtained are promising where the adsorption of leachate by zeolite further enhanced the removal of ammoniacal nitrogen and COD up to 96 and 43 %, respectively. Furthermore, this combined biological–physical treatment system was able to remove heavy metals, i.e. aluminium, vanadium, chromium, magnesium, cuprum and plumbum significantly. These results demonstrate that combined ASBR and zeolite adsorption is a feasible technique for the treatment of landfill leachate, even considering this effluent’s high resistance to treatment

    Longitudinal Current Dissipation in Bose-glass Superconductors

    Full text link
    A scaling theory of vortex motion in Bose glass superconductors with currents parallel to the common direction of the magnetic field and columnar defects is presented. Above the Bose-glass transition the longitudinal DC resistivity ÏâˆŁâˆŁ(T)∌(T−TBG)Îœâ€Čzâ€Č\rho_{||}(T)\sim (T-T_{BG})^{\nu' z'} vanishes much faster than the corresponding transverse resistivity ρ⊄(T)∌(T−TBG)Îœâ€Č(zâ€Č−2)\rho_{\perp}(T)\sim (T-T_{BG})^{\nu' (z'-2)}, thus {\it reversing} the usual anisotropy of electrical transport in the normal state of layered superconductors. In the presence of a current J\bf J at an angle ΞJ\theta_J with the common field and columnar defect axis, the electric field angle ΞE\theta_E approaches π/2\pi/2 as T→TBG+T\rightarrow T_{BG}^+. Scaling also predicts the behavior of penetration depths for the AC currents as T→TBG−T\rightarrow T_{BG}^-, and implies a {\it jump discontinuity} at TBGT_{BG} in the superfluid density describing transport parallel to the columns.Comment: 5 pages, revte

    Melting of Flux Lines in an Alternating Parallel Current

    Full text link
    We use a Langevin equation to examine the dynamics and fluctuations of a flux line (FL) in the presence of an {\it alternating longitudinal current} J∄(ω)J_{\parallel}(\omega). The magnus and dissipative forces are equated to those resulting from line tension, confinement in a harmonic cage by neighboring FLs, parallel current, and noise. The resulting mean-square FL fluctuations are calculated {\it exactly}, and a Lindemann criterion is then used to obtain a nonequilibrium `phase diagram' as a function of the magnitude and frequency of J∄(ω)J_{\parallel}(\omega). For zero frequency, the melting temperature of the mixed phase (a lattice, or the putative "Bose" or "Bragg Glass") vanishes at a limiting current. However, for any finite frequency, there is a non-zero melting temperature.Comment: 5 pages, 1 figur

    Extracts of Feijoa Inhibit Toll-Like Receptor 2 Signaling and Activate Autophagy Implicating a Role in Dietary Control of IBD

    Get PDF
    Inflammatory bowel disease (IBD) is a heterogeneous chronic inflammatory disease affecting the gut with limited treatment success for its sufferers. This suggests the need for better understanding of the different subtypes of the disease as well as nutritional interventions to compliment current treatments. In this study we assess the ability of a hydrophilic feijoa fraction (F3) to modulate autophagy a process known to regulate inflammation, via TLR2 using IBD cell lines
    • 

    corecore