16 research outputs found
Penetration of Commercial and Dental Waxes
Penetration of commercial and dental waxes was studied. Measurements indicated that resistance of paraffin and dental inlay waxes to penetration was closely related to the temperature at which solid-solid transformations occurred. Annealed waxes were more resistant to penetration than unannealed waxes.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67386/2/10.1177_00220345740530023701.pd
Differential Thermal Analysis of Commercial and Dental Waxes
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67104/2/10.1177_00220345670460051701.pd
The trans-activation domain of the sporulation response regulator Spo0A revealed by X-ray crystallography
Sporulation in Bacillus involves the induction of scores of genes in a temporally and spatially co-ordinated programme of cell development. Its initiation is under the control of an expanded two-component signal transduction system termed a phosphorelay. The master control element in the decision to sporulate is the response regulator, Spo0A, which comprises a receiver or phosphoacceptor domain and an effector or transcription activation domain. The receiver domain of Spo0A shares sequence similarity with numerous response regulators, and its structure has been determined in phosphorylated and unphosphorylated forms. However, the effector domain (C-Spo0A) has no detectable sequence similarity to any other protein, and this lack of structural information is an obstacle to understanding how DNA binding and transcription activation are controlled by phosphorylation in Spo0A. Here, we report the crystal structure of C-Spo0A from Bacillus stearothermophilus revealing a single alpha -helical domain comprising six alpha -helices in an unprecedented fold. The structure contains a helix-turn-helix as part of a three alpha -helical bundle reminiscent of the catabolite gene activator protein (CAP), suggesting a mechanism for DNA binding. The residues implicated in forming the sigma (A)-activating region clearly cluster in a flexible segment of the polypeptide on the opposite side of the structure from that predicted to interact with DNA. The structural results are discussed in the context of the rich array of existing mutational data
Phylogenomics and the rise of the angiosperms
Angiosperms are the cornerstone of most terrestrial ecosystems and human livelihoods1,2. A robust understanding of angiosperm evolution is required to explain their rise to ecological dominance. So far, the angiosperm tree of life has been determined primarily by means of analyses of the plastid genome3,4. Many studies have drawn on this foundational work, such as classification and first insights into angiosperm diversification since their Mesozoic origins5,6,7. However, the limited and biased sampling of both taxa and genomes undermines confidence in the tree and its implications. Here, we build the tree of life for almost 8,000 (about 60%) angiosperm genera using a standardized set of 353 nuclear genes8. This 15-fold increase in genus-level sampling relative to comparable nuclear studies9 provides a critical test of earlier results and brings notable change to key groups, especially in rosids, while substantiating many previously predicted relationships. Scaling this tree to time using 200 fossils, we discovered that early angiosperm evolution was characterized by high gene tree conflict and explosive diversification, giving rise to more than 80% of extant angiosperm orders. Steady diversification ensued through the remaining Mesozoic Era until rates resurged in the Cenozoic Era, concurrent with decreasing global temperatures and tightly linked with gene tree conflict. Taken together, our extensive sampling combined with advanced phylogenomic methods shows the deep history and full complexity in the evolution of a megadiverse clade
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Applying Normal PedEyeQ Thresholds to Assess Eye-related Quality of Life among Children with Strabismus
Purpose: To determine proportions of children with strabismus with below-normal Pediatric Eye Questionnaire (PedEyeQ) scores. Methods: Ninety-eight children with strabismus (70 aged 5â11 years; 28 aged 12â17 years) were evaluated. Children completed the Child 5â11 or 12â17 PedEyeQ (Functional Vision, Bothered by Eyes/vision, Social, and Frustration/worry domains). Parents completed the Proxy (same domains plus Eye Care) and Parent PedEyeQ (Impact on Parent and Family, Worry about Childâs Eye Condition, Worry about Childâs Self-perception and Interactions, and Worry about Functional Vision domains). Previously published normal (5th percentile) thresholds were applied to calculate proportions with below-normal scores for each domain. Results: For the Child PedEyeQ more than 20% of 5- to 11-year-olds scored below normal, on all but the Social domain, whereas more than 50% of 12- to 17-year-olds scored below normal on all domains. On the Proxy PedEyeQ, more than 50% scored below normal on all domains when parents reported on 5- to 11-year-olds and 12- to 17-year-olds. For the Parent PedEyeQ, more than 50% of the parents of both 5- to 11-year-olds and 12- to 17-year-olds scored below normal on all domains. Conclusions: The majority of children with strabismus have below-normal PedEyeQ scores, particularly children aged 12â17 years.12 month embargo; published online: 01 February 2022This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]