37 research outputs found

    Idiopathic radiographic apical root resorption in wind instrument players

    Get PDF
    Root resorption of the permanent teeth involves an elaborate interaction among inflammatory cells resulting in loss of dental hard tissues. This report describes three clinical cases where idiopathic root resorption occurred in wind instrument playing patients. These patients produce adequate non-orthodontic forces, while playing their instruments, to expose their teeth to root resorbing force. Careful clinical monitoring of patients' teeth should be undertaken, as the additive effects of orthodontic treatment and musical habits are unknown

    Solution structure of the dimerization domain of ribosomal protein P2 provides insights for the structural organization of eukaryotic stalk

    Get PDF
    The lateral stalk of ribosome is responsible for kingdom-specific binding of translation factors and activation of GTP hydrolysis that drives protein synthesis. In eukaryotes, the stalk is composed of acidic ribosomal proteins P0, P1 and P2 that constitute a pentameric P-complex in 1: 2: 2 ratio. We have determined the solution structure of the N-terminal dimerization domain of human P2 (NTD-P2), which provides insights into the structural organization of the eukaryotic stalk. Our structure revealed that eukaryotic stalk protein P2 forms a symmetric homodimer in solution, and is structurally distinct from the bacterial counterpart L12 homodimer. The two subunits of NTD-P2 form extensive hydrophobic interactions in the dimeric interface that buries 2400 Å2 of solvent accessible surface area. We have showed that P1 can dissociate P2 homodimer spontaneously to form a more stable P1/P2 1 : 1 heterodimer. By homology modelling, we identified three exposed polar residues on helix-3 of P2 are substituted by conserved hydrophobic residues in P1. Confirmed by mutagenesis, we showed that these residues on helix-3 of P1 are not involved in the dimerization of P1/P2, but instead play a vital role in anchoring P1/P2 heterodimer to P0. Based on our results, models of the eukaryotic stalk complex were proposed

    Solution structure of the dimerization domain of ribosomal protein P2 provides insights for the structural organization of eukaryotic stalk

    Get PDF
    The lateral stalk of ribosome is responsible for kingdom-specific binding of translation factors and activation of GTP hydrolysis that drives protein synthesis. In eukaryotes, the stalk is composed of acidic ribosomal proteins P0, P1 and P2 that constitute a pentameric P-complex in 1: 2: 2 ratio. We have determined the solution structure of the N-terminal dimerization domain of human P2 (NTD-P2), which provides insights into the structural organization of the eukaryotic stalk. Our structure revealed that eukaryotic stalk protein P2 forms a symmetric homodimer in solution, and is structurally distinct from the bacterial counterpart L12 homodimer. The two subunits of NTD-P2 form extensive hydrophobic interactions in the dimeric interface that buries 2400 Å2 of solvent accessible surface area. We have showed that P1 can dissociate P2 homodimer spontaneously to form a more stable P1/P2 1 : 1 heterodimer. By homology modelling, we identified three exposed polar residues on helix-3 of P2 are substituted by conserved hydrophobic residues in P1. Confirmed by mutagenesis, we showed that these residues on helix-3 of P1 are not involved in the dimerization of P1/P2, but instead play a vital role in anchoring P1/P2 heterodimer to P0. Based on our results, models of the eukaryotic stalk complex were proposed

    The UK Biobank imaging enhancement of 100,000 participants: rationale, data collection, management and future directions

    Get PDF
    UK Biobank is a population-based cohort of half a million participants aged 40–69 years recruited between 2006 and 2010. In 2014, UK Biobank started the world’s largest multi-modal imaging study, with the aim of re-inviting 100,000 participants to undergo brain, cardiac and abdominal magnetic resonance imaging, dual-energy X-ray absorptiometry and carotid ultrasound. The combination of large-scale multi-modal imaging with extensive phenotypic and genetic data offers an unprecedented resource for scientists to conduct health-related research. This article provides an in-depth overview of the imaging enhancement, including the data collected, how it is managed and processed, and future direction

    A multi-nuclide approach to constrain landscape evolution and past erosion rates in previously glaciated terrains

    Get PDF
    Cosmogenic nuclides are typically used to either constrain an exposure age, a burial age, or an erosion rate. Constraining the landscape history and past erosion rates in previously glaciated terrains is, however, notoriously difficult because it involves a large number of unknowns. The potential use of cosmogenic nuclides in landscapes with a complex history of exposure and erosion is therefore often quite limited. Here, we present a novel multi-nuclide approach to study the landscape evolution and past erosion rates in terrains with a complex exposure history, particularly focusing on regions that were repeatedly covered by glaciers or ice sheets during the Quaternary. The approach, based on the Markov Chain Monte Carlo (MCMC) technique, focuses on mapping the range of landscape histories that are consistent with a given set of measured cosmogenic nuclide concentrations. A fundamental assumption of the model approach is that the exposure history at the site/location can be divided into two distinct regimes: i) interglacial periods characterized by zero shielding due to overlying ice and a uniform interglacial erosion rate, and ii) glacial periods characterized by 100% shielding and a uniform glacial erosion rate. We incorporate the exposure history in the model framework by applying a threshold value to the global marine benthic δ18O record and include the threshold value as a free model parameter, hereby taking into account global changes in climate. However, any available information on the glacial-interglacial history at the sampling location, in particular the timing of the last deglaciation event, is readily incorporated in the model to constrain the inverse problem. Based on the MCMC technique, the model delineates the most likely exposure history, including the glacial and interglacial erosion rates, which, in turn, makes it possible to reconstruct an exhumation history at the site. We apply the model to two landscape scenarios based on synthetic data and two landscape scenarios based on paired 10Be/26Al data from West Greenland, which makes it possible to quantify the denudation rate at these locations. The model framework, which currently incorporates any combination of the following nuclides 10Be, 26Al, 14C, and 21Ne, is highly flexible and can be adapted to many different landscape settings. The model framework may also be used in combination with physics-based landscape evolution models to predict nuclide concentrations at different locations in the landscape. This may help validate the landscape models via comparison to measured nuclide concentrations or to devise new effective sampling strategies
    corecore