1,287 research outputs found

    Implant-Based Reconstruction following Mastectomy in Patients Who Have Had a Previous Breast Augmentation:Lessons from the National Multicenter Implant Breast Reconstruction Evaluation Study

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    Background: Breast augmentation is the most commonly performed cosmetic procedure, and increasingly women in this group present with breast cancer or request risk-reducing surgery, but their optimal management is unclear. The authors explored the clinical and patient-reported outcomes of patients undergoing immediate implant-based breast reconstruction following previous augmentation and compared these with outcomes of patients who had not had cosmetic implants in the Implant Breast Reconstruction Evaluation (iBRA) Study.   Methods: Patients undergoing immediate implant-based breast reconstruction were prospectively recruited from breast and plastic surgical units across the United Kingdom. Demographic, operative, and oncologic data, and information regarding complications within 3 postoperative months were collected. Patient-reported outcomes at 18 months were assessed using the BREAST-Q. The clinical and patient-reported outcomes of patients undergoing immediate implant-based breast reconstruction with and without previous breast augmentation were compared.   Results: A total of 2108 women were included in the iBRA Study, of whom 49 had undergone a previous augmentation. Women in the augmentation group were younger (median age, 45 years versus 50 years; p = 0.01), had a lower body mass index (22.8 kg/m2 versus 24.9 kg/m2; p < 0.01), and had smaller tumors (15 mm versus 25 mm; p = 0.01) than patients without augmentation. No differences were seen in operative technique between the groups. Complications at 3 months were similar in both groups and there were no significant differences in patient-reported outcomes at 18 months.   Conclusions: The clinical and patient-reported outcomes of patients undergoing immediate implant-based breast reconstruction following previous augmentation are consistent with those observed in the wider iBRA Study cohort, supporting the safety of this approach

    Corrigendum to “Comparative genomics and pan-genomics of the Myxococcaceae, including a description of five novel species:Myxococcus eversor sp. nov., Myxococcus llanfairpwllgwyngyllgogerychwyrndrobwllllantysiliogogogochensis sp. nov., Myxococcus vastator sp. nov., Pyxidicoccus caerfyrddinensis sp. nov. and Pyxidicoccus trucidator sp. nov.” [Genome Biol. Evol. 12(12) (2020) 2289-2302]

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    FIG. 2.—Scanning electron micrographs of typical myxobacterial cells. (A) strain AM401, (B) strain CA060A. Bars are 5 mm long.Published as part of Chambers, James, Sparks, Natalie, Sydney, Natashia, Livingstone, Paul G, Cookson, Alan R & Whitworth, David E, 2020, Comparative Genomics and Pan-Genomics of the Myxococcaceae, including a Description of Five Novel Species: Myxococcus eversor sp. nov., Myxococcus llanfairpwllgwyngyllgogerychwyrndrobwllllantysiliogogogochensis sp. nov., Myxococcus vastator sp. nov., Pyxidicoccus caerfyrddinensis sp. nov., and Pyxidicoccus trucidator sp. nov., pp. 2289-2302 in Genome Biology and Evolution 12 (12) on page 2294, DOI: 10.1093/gbe/evaa212, http://zenodo.org/record/456162

    Gravitational quasinormal modes for Anti-de Sitter black holes

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    Quasinormal mode spectra for gravitational perturbations of black holes in four dimensional de Sitter and anti-de Sitter space are investigated. The anti-de Sitter case is relevant to the ADS-CFT correspondence in superstring theory. The ADS-CFT correspondence suggests a prefered set of boundary conditions.Comment: 12 pages, 6 figures in ReVTe

    The effects of dibutyryl cyclic adenosine 3': 5'-monophosphate on concanavalin a-stimulated sterol and fatty acid synthesis in mouse spleen lymphocytes

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    Substantial increases in both 3[beta]-OH sterol and fatty acid synthesis were observed after concanavalin A addition to mouse spleen lymphocytes cultured in serum-free media. The rate of sterol synthesis increased linearly up to 60 h. The rate of fatty acid synthesis increased up to 20 h, reaching a plateau in synthetic activity which was the maintained. CO2 production from acetate was slightly stimulated by concanavalin A. In contrast to sterol and fatty acid synthesis, the rate of CO2 production in both mitogen-stimulated and resting cultures declined with time. Dibutyryl cyclic AMP had a strong inhibitory effect on concanavalin A-stimulated sterol and fatty acid synthesis from acetate, but only a slight effect on CO2 production. Delayed addition of dibutyryl cyclic AMP resulted in reduced inhibition. The data suggest a sequence of initiation for fatty acid and sterol synthesis prior to DNA synthesis and a possible regulatory role of cyclic AMP in this initiation. The results support the hypothesis that lymphocyte activation is sequential within the spleen cell population and is accompanied by fatty acid and sterol synthesis.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/22613/1/0000163.pd

    Sequence level mechanisms of human epigenome evolution

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    DNA methylation and chromatin states play key roles in development and disease. However, the extent of recent evolutionary divergence in the human epigenome and the influential factors that have shaped it are poorly understood. To determine the links between genome sequence and human epigenome evolution, we examined the divergence of DNA methylation and chromatin states following segmental duplication events in the human lineage. Chromatin and DNA methylation states were found to have been generally well conserved following a duplication event, with the evolution of the epigenome largely uncoupled from the total number of genetic changes in the surrounding DNA sequence. However, the epigenome at tissue-specific, distal regulatory regions was observed to be unusually prone to diverge following duplication, with particular sequence differences, altering known sequence motifs, found to be associated with divergence in patterns of DNA methylation and chromatin. Alu elements were found to have played a particularly prominent role in shaping human epigenome evolution, and we show that human-specific AluY insertion events are strongly linked to the evolution of the DNA methylation landscape and gene expression levels, including at key neurological genes in the human brain. Studying paralogous regions within the same sample enables the study of the links between genome and epigenome evolution while controlling for biological and technical variation. We show DNA methylation and chromatin divergence between duplicated regions are linked to the divergence of particular genetic motifs, with Alu elements having played a disproportionate role in the evolution of the epigenome in the human lineage

    An assessment of the methodological quality of published network meta-analyses: a systematic review

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    Objective To assess the methodological quality of published network meta-analysis. Design Systematic review. Methods We searched the medical literature for network meta-analyses of pharmaceuticals. We assessed general study characteristics, study transparency and reproducibility, methodological approach, and reporting of findings. We compared studies published in journals with lower impact factors with those published in journals with higher impact factors, studies published prior to January 1st, 2013 with those published after that date, and studies supported financially by industry with those supported by non-profit institutions or that received no support. Results The systematic literature search identified 854 citations. Three hundred and eighteen studies met our inclusion criteria. The number of network meta-analyses has grown rapidly, with 48% of studies published since January 2013. The majority of network meta-analyses were supported by a non-profit institution or received no support (68%). We found considerable inconsistencies among reviewed studies. Eighty percent reported search terms, 61% a network diagram, 65% sufficient data to replicate the analysis, and 90% the characteristics of included trials. Seventy percent performed a risk of bias assessment of included trials, 40% an assessment of model fit, and 56% a sensitivity analysis. Among studies with a closed loop, 69% examined the consistency of direct and indirect evidence. Sixty-four percent of studies presented the full matrix of head-to-head treatment comparisons. For Bayesian studies, 41% reported the probability that each treatment was best, 31% reported treatment ranking, and 16% included the model code or referenced publicly-available code. Network meta-analyses published in higher impact factors journals and those that did not receive industry support performed better across the assessment criteria. We found few differences between older and newer studies. Conclusions There is substantial variation in the network meta-analysis literature. Consensus among guidelines is needed improve the methodological quality, transparency, and consistency of study conduct and reporting

    Polarizing Grids, Their Assemblies and Beams of Radiation

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    This article gives an analysis of the behavior of polarizing grids and reflecting polarizers by solving Maxwell's equations, for arbitrary angles of incidence and grid rotation, for cases where the excitation is provided by an incident plane wave or a beam of radiation. The scattering and impedance matrix representations are derived and used to solve more complicated configurations of grid assemblies. The results are also compared with data obtained in the calibration of reflecting polarizers at the Owens Valley Radio Observatory (OVRO). From this analysis, we propose a method for choosing the optimum grid parameters (wire radius and spacing). We also provide a study of the effects of two types of errors (in wire separation and radius size) that can be introduced in the fabrication of a grid.Comment: 35 pages, 6 figure

    The Time-Domain Spectroscopic Survey: Understanding the Optically Variable Sky with SEQUELS in SDSS-III

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    The Time-Domain Spectroscopic Survey (TDSS) is an SDSS-IV eBOSS subproject primarily aimed at obtaining identification spectra of ~220,000 optically-variable objects systematically selected from SDSS/Pan-STARRS1 multi-epoch imaging. We present a preview of the science enabled by TDSS, based on TDSS spectra taken over ~320 deg^2 of sky as part of the SEQUELS survey in SDSS-III, which is in part a pilot survey for eBOSS in SDSS-IV. Using the 15,746 TDSS-selected single-epoch spectra of photometrically variable objects in SEQUELS, we determine the demographics of our variability-selected sample, and investigate the unique spectral characteristics inherent in samples selected by variability. We show that variability-based selection of quasars complements color-based selection by selecting additional redder quasars, and mitigates redshift biases to produce a smooth quasar redshift distribution over a wide range of redshifts. The resulting quasar sample contains systematically higher fractions of blazars and broad absorption line quasars than from color-selected samples. Similarly, we show that M-dwarfs in the TDSS-selected stellar sample have systematically higher chromospheric active fractions than the underlying M-dwarf population, based on their H-alpha emission. TDSS also contains a large number of RR Lyrae and eclipsing binary stars with main-sequence colors, including a few composite-spectrum binaries. Finally, our visual inspection of TDSS spectra uncovers a significant number of peculiar spectra, and we highlight a few cases of these interesting objects. With a factor of ~15 more spectra, the main TDSS survey in SDSS-IV will leverage the lessons learned from these early results for a variety of time-domain science applications.Comment: 17 pages, 14 figures, submitted to Ap
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