187 research outputs found
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Transfer RNA genes experience exceptionally elevated mutation rates.
Transfer RNAs (tRNAs) are a central component for the biological synthesis of proteins, and they are among the most highly conserved and frequently transcribed genes in all living things. Despite their clear significance for fundamental cellular processes, the forces governing tRNA evolution are poorly understood. We present evidence that transcription-associated mutagenesis and strong purifying selection are key determinants of patterns of sequence variation within and surrounding tRNA genes in humans and diverse model organisms. Remarkably, the mutation rate at broadly expressed cytosolic tRNA loci is likely between 7 and 10 times greater than the nuclear genome average. Furthermore, evolutionary analyses provide strong evidence that tRNA genes, but not their flanking sequences, experience strong purifying selection acting against this elevated mutation rate. We also find a strong correlation between tRNA expression levels and the mutation rates in their immediate flanking regions, suggesting a simple method for estimating individual tRNA gene activity. Collectively, this study illuminates the extreme competing forces in tRNA gene evolution and indicates that mutations at tRNA loci contribute disproportionately to mutational load and have unexplored fitness consequences in human populations
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Low work function material development for the microminiature thermionic converter.
Thermionic energy conversion in a miniature format shows potential as a viable, high efficiency, micro to macro-scale power source. A microminiature thermionic converter (MTC) with inter-electrode spacings on the order of microns has been prototyped and evaluated at Sandia. The remaining enabling technology is the development of low work function materials and processes that can be integrated into these converters to increase power production at modest temperatures (800 - 1300 K). The electrode materials are not well understood and the electrode thermionic properties are highly sensitive to manufacturing processes. Advanced theoretical, modeling, and fabrication capabilities are required to achieve optimum performance for MTC diodes. This report describes the modeling and fabrication efforts performed to develop micro dispenser cathodes for use in the MTC
The Vehicle, Spring 1994
Table of Contents
Thoughts in the IGASue Songerpage 6
The Cries of an Innocent Tea BagWojnarowski Yvonnepage 7
Proud HarpySusan Eisenhourpage 8
Bus Number TwoMindy Glazepage 9
My Home TownScott Langenpage 10
MemoriesMaggie Willpage 11
Vase (Artwork)Gail Valkerpage 12
The Last HuntMark Kannmacherpage 13
Corn DanceJulia A. Canhampage 14
Untitled (Photography)Rachel Corbettpage 14
Paradise (Artwork)Gail Valkerpage 15
Holding Back A ScreamElise Kirarpage 16
poetry isJonathan W. Iwanskipage 17
loveCatherine DeGraafpage 18
The OneTim Rileypage 18
Reading His Words on a Frosty EveningTom McGrathpage 19
UntitledBob Newellpage 19
The Ice StormMindy Glazepage 20
UntitledJonathan W. Iwanskipage 21
Untitled (Photography)Rachel Corbettpage 23
cityscapeChris Pomeroypage 24
Untitled (Photography)Rachel Corbettpage 25
Quarter Pound TemptationBryan Levekpage 26
Photograph (Artwork)Gail Valkerpage 29
Don\u27t Talk to StrangersJon Montgomerypage 30
Untitled (Photography)Rachel Corbettpage 33
Charleston, U.S.A. (Artwork)Gail Valkerpage 34
Fun With Nature (Artwork)Gail Valkerpage 34https://thekeep.eiu.edu/vehicle/1064/thumbnail.jp
Total Daily Pill Burden in HIV-Infected Patients in the Southern United States
The need for antiretroviral therapy coupled with treatment of chronic co-morbidities places HIV-infected patients at risk for polypharmacy. However, few studies have described overall pill burden among HIV-infected patients. HIV-infected outpatients of the UNC Infectious Diseases Clinic were enrolled in this cross-sectional study. Subjects were contacted prior to a scheduled appointment and asked to bring all their medications to the visit. Daily total pill burden and medication type were recorded. 151 subjects were recruited: 76% male, 58% African American, 97% receiving antiretrovirals (ARVs). Median age was 48 (IRQ: 42–54) years. The median number of medications per subject was 8 (IQR: 6–11), and the median individual daily pill burden was 8 pills (IQR: 5–15): 3 pills (range: 2–5) for ARVs and 6 (range: 3–12.5) pills for non-ARVs. Duration of ART (per 2 years increase) and more than 3 co-morbidities was significantly associated with high pill burden (over 10 pills per day) with adjusted OR of 2.09 (95% CI, 1.14–3.84) and 8.04 (95% CI, 2.30–28.15), respectively. As patients with HIV age, strategies to reduce pill burden and number of medications will become increasingly critical to maintaining adherence, preventing medication errors, and serious drug–drug interactions
Stability of SARS-CoV-2 phylogenies.
Funder: Alfred P. Sloan Foundation; funder-id: http://dx.doi.org/10.13039/100000879Funder: European Molecular Biology Laboratory (EMBL)The SARS-CoV-2 pandemic has led to unprecedented, nearly real-time genetic tracing due to the rapid community sequencing response. Researchers immediately leveraged these data to infer the evolutionary relationships among viral samples and to study key biological questions, including whether host viral genome editing and recombination are features of SARS-CoV-2 evolution. This global sequencing effort is inherently decentralized and must rely on data collected by many labs using a wide variety of molecular and bioinformatic techniques. There is thus a strong possibility that systematic errors associated with lab-or protocol-specific practices affect some sequences in the repositories. We find that some recurrent mutations in reported SARS-CoV-2 genome sequences have been observed predominantly or exclusively by single labs, co-localize with commonly used primer binding sites and are more likely to affect the protein-coding sequences than other similarly recurrent mutations. We show that their inclusion can affect phylogenetic inference on scales relevant to local lineage tracing, and make it appear as though there has been an excess of recurrent mutation or recombination among viral lineages. We suggest how samples can be screened and problematic variants removed, and we plan to regularly inform the scientific community with our updated results as more SARS-CoV-2 genome sequences are shared (https://virological.org/t/issues-with-sars-cov-2-sequencing-data/473 and https://virological.org/t/masking-strategies-for-sars-cov-2-alignments/480). We also develop tools for comparing and visualizing differences among very large phylogenies and we show that consistent clade- and tree-based comparisons can be made between phylogenies produced by different groups. These will facilitate evolutionary inferences and comparisons among phylogenies produced for a wide array of purposes. Building on the SARS-CoV-2 Genome Browser at UCSC, we present a toolkit to compare, analyze and combine SARS-CoV-2 phylogenies, find and remove potential sequencing errors and establish a widely shared, stable clade structure for a more accurate scientific inference and discourse
Bringing People Back into Public Health Data: Community Feedback on a Set of Visualization Tools - Summary Report
This course-based study is a product of the University of Denver’s Spring 2022 The Social Determination of Health (ANTH 2424) class. The study aimed to understand how well a set of public health visualization tools tells the data stories about people in Colorado, and about important public health problems. For this, a team of almost sixty undergraduate students taking the class, coordinated by three graduate teaching assistants, and directed by the course instructor interviewed a total of fifty-six people from Colorado, qualitatively analyzed those interviews, and wrote reports that draw conclusions and recommendations
Interventions for hyperhidrosis in secondary care : a systematic review and value-of-information analysis
Background: Hyperhidrosis is uncontrollable excessive sweating that occurs at rest, regardless of temperature. The symptoms of hyperhidrosis can significantly affect quality of life. The management of hyperhidrosis is uncertain and variable. Objective: To establish the expected value of undertaking additional research to determine the most effective interventions for the management of refractory primary hyperhidrosis in secondary care. Methods: A systematic review and economic model, including a value-of-information (VOI) analysis. Treatments to be prescribed by dermatologists and minor surgical treatments for hyperhidrosis of the hands, feet and axillae were reviewed; as endoscopic thoracic sympathectomy (ETS) is incontestably an end-of-line treatment, it was not reviewed further. Fifteen databases (e.g. CENTRAL, PubMed and PsycINFO), conference proceedings and trial registers were searched from inception to July 2016. Systematic review methods were followed. Pairwise meta-analyses were conducted for comparisons between botulinum toxin (BTX) injections and placebo for axillary hyperhidrosis, but otherwise, owing to evidence limitations, data were synthesised narratively. A decision-analytic model assessed the cost-effectiveness and VOI of five treatments (iontophoresis, medication, BTX, curettage, ETS) in 64 different sequences for axillary hyperhidrosis only. Results and conclusions: Fifty studies were included in the effectiveness review: 32 randomised controlled trials (RCTs), 17 non-RCTs and one large prospective case series. Most studies were small, rated as having a high risk of bias and poorly reported. The interventions assessed in the review were iontophoresis, BTX, anticholinergic medications, curettage and newer energy-based technologies that damage the sweat gland (e.g. laser, microwave). There is moderate-quality evidence of a large statistically significant effect of BTX on axillary hyperhidrosis symptoms, compared with placebo. There was weak but consistent evidence for iontophoresis for palmar hyperhidrosis. Evidence for other interventions was of low or very low quality. For axillary hyperhidrosis cost-effectiveness results indicated that iontophoresis, BTX, medication, curettage and ETS was the most cost-effective sequence (probability 0.8), with an incremental cost-effectiveness ratio of £9304 per quality-adjusted life-year. Uncertainty associated with study bias was not reflected in the economic results. Patients and clinicians attending an end-of-project workshop were satisfied with the sequence of treatments for axillary hyperhidrosis identified as being cost-effective. All patient advisors considered that the Hyperhidrosis Quality of Life Index was superior to other tools commonly used in hyperhidrosis research for assessing quality of life. Limitations: The evidence for the clinical effectiveness and safety of second-line treatments for primary hyperhidrosis is limited. This meant that there was insufficient evidence to draw conclusions for most interventions assessed and the cost-effectiveness analysis was restricted to hyperhidrosis of the axilla. Future work: Based on anecdotal evidence and inference from evidence for the axillae, participants agreed that a trial of BTX (with anaesthesia) compared with iontophoresis for palmar hyperhidrosis would be most useful. The VOI analysis indicates that further research into the effectiveness of existing medications might be worthwhile, but it is unclear that such trials are of clinical importance. Research that established a robust estimate of the annual incidence of axillary hyperhidrosis in the UK population would reduce the uncertainty in future VOI analyses
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