42 research outputs found
Breast MRI Utilization in Older Patients with Newly Diagnosed Breast Cancer
Recently, use of advanced imaging modalities, such as MRI, has increased dramatically. One novel but still evolving use for MRI is in the diagnosis and clinical staging of newly diagnosed breast cancer patients. Compared with mammography, MRI is more sensitive, but less specific, and far more expensive. The purpose of this study is to examine the prevalence and predictors of MRI use for clinical staging in older women with newly diagnosed breast cancer
Phase 2 Study of the Safety and Tolerability of Maraviroc-Containing Regimens to Prevent HIV Infection in Men Who Have Sex With Men (HPTN 069/ACTG A5305)
Maraviroc (MVC) is a candidate for human immunodeficiency virus (HIV) pre-exposure prophylaxis
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Transiting Exoplanet Survey Satellite
The Transiting Exoplanet Survey Satellite (TESS) will search for planets transiting bright and nearby stars. TESS has been selected by NASA for launch in 2017 as an Astrophysics Explorer mission. The spacecraft will be placed into a highly elliptical 13.7-day orbit around the Earth. During its 2-year mission, TESS will employ four wide-field optical charge-coupled device cameras to monitor at least 200,000 main-sequence dwarf stars with IC≈4−13IC≈4−13 for temporary drops in brightness caused by planetary transits. Each star will be observed for an interval ranging from 1 month to 1 year, depending mainly on the star’s ecliptic latitude. The longest observing intervals will be for stars near the ecliptic poles, which are the optimal locations for follow-up observations with the James Webb Space Telescope. Brightness measurements of preselected target stars will be recorded every 2 min, and full frame images will be recorded every 30 min. TESS stars will be 10 to 100 times brighter than those surveyed by the pioneering Kepler mission. This will make TESS planets easier to characterize with follow-up observations. TESS is expected to find more than a thousand planets smaller than Neptune, including dozens that are comparable in size to the Earth. Public data releases will occur every 4 months, inviting immediate community-wide efforts to study the new planets. The TESS legacy will be a catalog of the nearest and brightest stars hosting transiting planets, which will endure as highly favorable targets for detailed investigations.Astronom
Development of Simple Sequence Repeat Markers for \u3ci\u3eChionanthus Retusus\u3c/i\u3e (Oleaceae) and Effective Discrimination of Closely Related Taxa
The genus Chionanthus (Oleaceae Hoffmans. & Link) includes deciduous or evergreen trees and shrubs distributed widely in tropical and sub-tropical areas, including a few temperate species. Although Chionanthus species are planted as ornamental garden plants and commercialized for natural products, genetic information for Chionanthus spp. is lacking. We created micro satellite-enriched libraries of Chionanthus retusus Lindl. & Paxton, assembled 1072 contigs, and detected 1010 repeats. The frequency of the repeats decreased with the increase in repeat length, and the most abundant motifs were: AG, AC, AAG, ACC, AT, and ACTC. We screened 384 markers on 12 accessions of four related taxa that included C. retusus, Chionanthus virginicus L., Chionanthus pygmaeus Small, and Osmanthus americanus (L.) Benth. & Hook. A total of 195 simple sequence repeat (SSR) markers amplified and discriminated six accessions of C. retusus and 57 SSR markers amplified and discriminated across the four Oleaceae species screened. To identify the best markers to use in future experiments, the ‘‘Unique Pattern Informative Combination’’ (UPIC) values were calculated for all the markers and the 100 markers that were most effective are reported here. The percentage of heterozygous loci across the 384 markers was lowest for C. retusus (29.3%) and highest for O. americanus (68.9%). The SSR markers developed here could assist in taxonomy and hybridization investigations for breeding programs and authentication of varieties used as medicinal plants
Regulation of gene expression in roots of the pH-sensitive Vaccinium corymbosum and the pH-tolerant Vaccinium arboreum in response to near neutral pH stress using RNA-Seq
Abstract Background Blueberries are one of the few horticultural crops adapted to grow in acidic soils. Neutral to basic soil pH is detrimental to all commonly cultivated blueberry species, including Vaccinium corymbosum (VC). In contrast, the wild species V. arboreum (VA) is able to tolerate a wider range of soil pH. To assess the molecular mechanisms involved in near neutral pH stress response, plants from pH-sensitive VC (tetraploid) and pH-tolerant VA (diploid) were grown at near neutral pH 6.5 and at the preferred pH of 4.5. Results Transcriptome sequencing of root RNA was performed for 4 biological replications per species x pH level interaction, for a total of 16 samples. Reads were mapped to the reference genome from diploid V. corymbosum, transforming ~55% of the reads to gene counts. A quasi-likelihood F test identified differential expression due to pH stress in 337 and 4867 genes in VA and VC, respectively. Both species shared regulation of genes involved in nutrient homeostasis and cell wall metabolism. VA and VC exhibited differential regulation of signaling pathways related to abiotic/biotic stress, cellulose and lignin biosynthesis, and nutrient uptake. Conclusions The specific responses in VA likely facilitate tolerance to higher soil pH. In contrast, response in VC, despite affecting a greater number of genes, is not effective overcoming the stress induced by pH. Further inspection of those genes with differential expression that are specific in VA may provide insight on the mechanisms towards tolerance
Complete chloroplast genome comparisons for Pityopsis (Asteraceae).
Pityopsis includes several regionally and one federally endangered species of herbaceous perennials. Four species are highly localized, including the federally endangered P. ruthii. The genus includes several ploidy levels and interesting ecological traits such as drought tolerance and fire-dependent flowering. Results from previous cladistic analyses of morphology and from initial DNA sequence studies did not agree with one another or with the infrageneric taxonomic classification, with the result that infrageneric relationships remain unresolved. We sequenced, assembled, and compared the chloroplast (cp) genomes of 12 species or varieties of Pityopsis to better understand generic evolution. A reference cp genome 152,569 bp in length was assembled de novo from P. falcata. Reads from other sampled species were then aligned to the P. falcata reference and individual chloroplast genomes were assembled for each, with manual gapfilling and polishing. After removing the duplicated second inverted region, a multiple sequence alignment of the cp genomes was used to construct a maximum likelihood (ML) phylogeny for the twelve cp genomes. Additionally, we constructed a ML phylogeny from the nuclear ribosomal repeat region after mapping reads to the Helianthus annuus region. The chloroplast phylogeny supported two clades. Previously proposed clades and taxonomic sections within the genus were largely unsupported by both nuclear and chloroplast phylogenies. Our results provide tools for exploring hybridity and examining the physiological and genetic basis for drought tolerance and fire-dependent flowering. This study will inform breeding and conservation practices, and general knowledge of evolutionary history, hybridization, and speciation within Pityopsis
Population Structure and Genetic Diversity Within the Endangered Species Pityopsis ruthii (Asteraceae)
Pityopsis ruthii (Ruth’s golden aster) is a federally endangered herbaceous perennial endemic to the Hiwassee and Ocoee Rivers in southeastern Tennessee, United States. Comprehensive genetic studies providing novel information to conservationists for preservation of the species are lacking. Genetic variation and gene flow were evaluated for 814 individuals from 33 discrete locations using polymorphic microsatellites: seven chloroplast and twelve nuclear. A total of 198 alleles were detected with the nuclear loci and 79 alleles with the chloroplast loci. Gene flow was estimated, with the Hiwassee River (Nm = 2.16; FST = 0.15) showing higher levels of gene flow and lower levels of population differentiation than the Ocoee River (Nm = 1.28; FST = 0.19). Population structure was examined using Bayesian cluster analyses. Nuclear and chloroplast analyses were incongruent. From the chloroplast microsatellites, three clusters were identified; all were present in sampling sites at both rivers, indicating a lack of allele fixation along rivers. Nuclear markers revealed two clusters and separated by river. When the Hiwassee River locations were analyzed, four clusters were identified for both the chloroplast and nuclear microsatellites, though the individuals clustered differently. Analysis of the Ocoee River revealed two clusters for the chloroplast microsatellites and three for the nuclear microsatellites. We recommend P. ruthii be managed as four populations for the Hiwassee River and three populations for the Ocoee River. Our results provide critical genetic information for P. ruthii that can be used for species management decisions to drive future population augmentation/reintroduction and ex situ conservation efforts
Table_3_Population Structure and Genetic Diversity Within the Endangered Species Pityopsis ruthii (Asteraceae).DOCX
<p>Pityopsis ruthii (Ruth’s golden aster) is a federally endangered herbaceous perennial endemic to the Hiwassee and Ocoee Rivers in southeastern Tennessee, United States. Comprehensive genetic studies providing novel information to conservationists for preservation of the species are lacking. Genetic variation and gene flow were evaluated for 814 individuals from 33 discrete locations using polymorphic microsatellites: seven chloroplast and twelve nuclear. A total of 198 alleles were detected with the nuclear loci and 79 alleles with the chloroplast loci. Gene flow was estimated, with the Hiwassee River (N<sub>m</sub> = 2.16; F<sub>ST</sub> = 0.15) showing higher levels of gene flow and lower levels of population differentiation than the Ocoee River (N<sub>m</sub> = 1.28; F<sub>ST</sub> = 0.19). Population structure was examined using Bayesian cluster analyses. Nuclear and chloroplast analyses were incongruent. From the chloroplast microsatellites, three clusters were identified; all were present in sampling sites at both rivers, indicating a lack of allele fixation along rivers. Nuclear markers revealed two clusters and separated by river. When the Hiwassee River locations were analyzed, four clusters were identified for both the chloroplast and nuclear microsatellites, though the individuals clustered differently. Analysis of the Ocoee River revealed two clusters for the chloroplast microsatellites and three for the nuclear microsatellites. We recommend P. ruthii be managed as four populations for the Hiwassee River and three populations for the Ocoee River. Our results provide critical genetic information for P. ruthii that can be used for species management decisions to drive future population augmentation/reintroduction and ex situ conservation efforts.</p