566 research outputs found
Comparative Analysis of RNA Families Reveals Distinct Repertoires for Each Domain of Life
The RNA world hypothesis, that RNA genomes and catalysts preceded DNA genomes
and genetically-encoded protein catalysts, has been central to models for the
early evolution of life on Earth. A key part of such models is continuity
between the earliest stages in the evolution of life and the RNA repertoires of
extant lineages. Some assessments seem consistent with a diverse RNA world, yet
direct continuity between modern RNAs and an RNA world has not been
demonstrated for the majority of RNA families, and, anecdotally, many RNA
functions appear restricted in their distribution. Despite much discussion of
the possible antiquity of RNA families, no systematic analyses of RNA family
distribution have been performed. To chart the broad evolutionary history of
known RNA families, we performed comparative genomic analysis of over 3 million
RNA annotations spanning 1446 families from the Rfam 10 database. We report
that 99% of known RNA families are restricted to a single domain of life,
revealing discrete repertoires for each domain. For the 1% of RNA
families/clans present in more than one domain, over half show evidence of
horizontal gene transfer, and the rest show a vertical trace, indicating the
presence of a complex protein synthesis machinery in the Last Universal Common
Ancestor (LUCA) and consistent with the evolutionary history of the most
ancient protein-coding genes. However, with limited interdomain transfer and
few RNA families exhibiting demonstrable antiquity as predicted under RNA world
continuity, our results indicate that the majority of modern cellular RNA
repertoires have primarily evolved in a domain-specific manner.Comment: 47 pages, 4 main figures, 3 supplementary figures, 4 supplementary
tables. Submitted to PLOS Computational Biolog
A combined experimental and computational study of the pressure dependence of the vibrational spectrum of solid picene C_22H_14
We present high-quality optical data and density functional perturbation
theory calculations for the vibrational spectrum of solid picene
(CH) under pressure up to 8 GPa. First-principles calculations
reproduce with a remarkable accuracy the pressure effects on both frequency and
intensities of the phonon peaks experimentally observed . Through a detailed
analysis of the phonon eigenvectors, We use the projection on molecular
eigenmodes to unambiguously fit the experimental spectra, resolving complicated
spectral structures, in a system with hundreds of phonon modes. With these
projections, we can also quantify the loss of molecular character under
pressure. Our results indicate that picene, despite a \sim 20 % compression of
the unit cell, remains substantially a molecular solid up to 8 GPa, with phonon
modes displaying a smooth and uniform hardening with pressure. The Grueneisen
parameter of the 1380 cm^{-1} a_1 Raman peak () is much lower
than the effective value () due to K doping. This is an
indication that the phonon softening in K doped samples is mainly due to charge
transfer and electron-phonon coupling.Comment: Replaced with final version (PRB
Detection of fixed points in spatiotemporal signals by clustering method
We present a method to determine fixed points in spatiotemporal signals. A
144-dimensioanl simulated signal, similar to a Kueppers-Lortz instability, is
analyzed and its fixed points are reconstructed.Comment: 3 pages, 3 figure
Combat‐Related Posttraumatic Stress Disorder and Comorbid Major Depression in U.S. Veterans: The Role of Deployment Cycle Adversity and Social Support
Posttraumatic stress disorder (PTSD) and major depressive disorder (MDD) commonly co‐occur in combat veterans, and this comorbidity has been associated with higher levels of distress and more social and economic costs compared to one disorder alone. In a secondary analysis of a multisite randomized controlled trial of a sample of veterans with combat‐related PTSD, we examined the associations among pre‐, peri‐, and postdeployment adversity, social support, and clinician‐diagnosed comorbid MDD. Participants completed the Deployment Risk and Resilience Inventory and the Beck Depression Inventory–II as well as structured clinical interviews for diagnostic status. Among 223 U.S. veterans of the military operations in Iraq and Afghanistan (86.9% male) with primary combat‐related PTSD, 69.5% had current comorbid MDD. After adjustment for sex, a linear regression model indicated that more concerns about family disruptions during deployment, f2 = 0.065; more harassment during deployment, f2 = 0.020; and lower ratings of postdeployment social support, f2 = 0.154, were associated with more severe self‐reported depression symptoms. Interventions that enhance social support as well as societal efforts to foster successful postdeployment reintegration are critical for reducing the mental health burden associated with this highly prevalent comorbidity in veterans with combat‐related PTSD.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/155948/1/jts22496_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/155948/2/jts22496.pd
Daily College Student Drinking Patterns Across the First Year of College
Objective:
Despite the long recognized importance and well-documented impact of drinking patterns on health and safety, college student drinking patterns are understudied. This study used a daily-level, academic-year-long, multisite sample to identify subpopulations of college student drinking patterns and to describe how these groups differ from one another before, during, and after their first year of college.
Method:
wo cohorts of first-year college students (n = 588; 59% female) reported daily drinking on a biweekly basis using web-based surveys and completed surveys before and after their first year of college.
Results:
Cluster analyses based on time series analysis estimates of within-person drinking differences (per weekday, semester, first 6 weeks) and other descriptors of day-to-day drinking identified five drinking patterns: two low (47% and 6%), two medium (24% and 15%), and one high (8%) drinking cluster. Multinomial logistic regression analyses examined cluster differences in pre-college characteristics (i.e., demographics, alcohol outcome expectancies, alcohol problems, depression, other substance use) and first-year college experiences (i.e., academic engagement, alcohol consequences, risky drinking practices, alcohol problems, drinking during academic breaks). Low-drinking students appeared to form a relatively homogeneous group, whereas two distinct patterns were found for medium-drinking students with different weekend and Thursday drinking rates. The Thursday drinking cluster showed lower academic engagement and greater participation in risky drinking practices.
Conclusions:
These findings highlight quantitative and qualitative differences in day-to-day drinking patterns and suggest a link between motivational differences and drinking patterns, which may be addressed in developing tailored interventional strategies
Discover EDS: Tales of Implementation and Use
This paper supplements the panel, which was delivered in a “Lively Lunch” format and included presentations by librarians who have employed EBSCO’s Discovery System (EDS) in their academic institutions. The panelists addressed several important aspects of launching a discovery system in an academic library, such as Implementation; Information Literacy; and Assessment, Usability and Customization. The implementation component included technical aspects, business requirements, enhancing the operability of link resolvers, launch preparation, and implementation success. The information literacy portion addressed how academic reference services and library instruction have been transformed because of EDS. Assessment, Usability and Customization focused on customizing the search box and assessing EDS using statistics and usability testing. Michael Gorrell, Executive Vice President of Technology and Chief Information Officer of EBSCO Publishing, was present, and a Q&A time was scheduled at the end of each session for audience members to ask questions, comment, and share experiences.
The implementation process of a Discovery Service involves many different aspects and is a large undertaking for any library. Depending on the size of the library, its technology infrastructure, and the number of staff involved, the implementation time can vary greatly. In addition, the planning processes and the considerations made prior to implementation are also affected by the nature and needs of end-users in these institutions. Selecting the resources to include in the discovery service, resolving technical issues, developing a strategy to publicize and market to end-users, and assessing and customizing the product are all part of a continuous course of implementing Discovery Services—a process that begins long before implementation and has no fixed completion. This process involves a collaborative and consorted effort from all areas of librarian expertise, from technical services to public services. The simplicity and comprehensiveness of discovery tools redefine how libraries deliver services across the board, changing the expectations users have of the experience of searching library resources and challenging librarians to redesign instruction and teach information literacy in new ways.
These considerations and our own experience with implementing EBSCO’s Discovery System (EDS) at the University of South Florida prompted us to open up a discussion across university and college libraries in the U.S. and across librarian functions, technical, and public services, in order to share, discuss, and learn from each other the lessons of Discovery Service implementation and use. We wanted to focus on the continuous nature of this process, involving the user perspective, as well as the perspective of the vendor, EBSCO. We believe that talking with our colleagues and collaborating with publishers makes us much better positioned to anticipate the changing needs of users and enhance the experience, accessibility, and discoverability of library content
Modular titanium alloy neck adapter failures in hip replacement - failure mode analysis and influence of implant material
<p>Abstract</p> <p>Background</p> <p>Modular neck adapters for hip arthroplasty stems allow the surgeon to modify CCD angle, offset and femoral anteversion intraoperatively. Fretting or crevice corrosion may lead to failure of such a modular device due to high loads or surface contamination inside the modular coupling. Unfortunately we have experienced such a failure of implants and now report our clinical experience with the failures in order to advance orthopaedic material research and joint replacement surgery.</p> <p>The failed neck adapters were implanted between August 2004 and November 2006 a total of about 5000 devices. After this period, the titanium neck adapters were replaced by adapters out of cobalt-chromium. Until the end of 2008 in total 1.4% (n = 68) of the implanted titanium alloy neck adapters failed with an average time of 2.0 years (0.7 to 4.0 years) postoperatively. All, but one, patients were male, their average age being 57.4 years (36 to 75 years) and the average weight 102.3 kg (75 to 130 kg). The failures of neck adapters were divided into 66% with small CCD of 130° and 60% with head lengths of L or larger. Assuming an average time to failure of 2.8 years, the cumulative failure rate was calculated with 2.4%.</p> <p>Methods</p> <p>A series of adapter failures of titanium alloy modular neck adapters in combination with a titanium alloy modular short hip stem was investigated. For patients having received this particular implant combination risk factors were identified which were associated with the occurence of implant failure. A Kaplan-Meier survival-failure-analysis was conducted. The retrieved implants were analysed using microscopic and chemical methods. Modes of failure were simulated in biomechanical tests. Comparative tests included modular neck adapters made of titanium alloy and cobalt chrome alloy material.</p> <p>Results</p> <p>Retrieval examinations and biomechanical simulation revealed that primary micromotions initiated fretting within the modular tapered neck connection. A continuous abrasion and repassivation process with a subsequent cold welding at the titanium alloy modular interface. Surface layers of 10 - 30 μm titanium oxide were observed. Surface cracks caused by fretting or fretting corrosion finally lead to fatigue fracture of the titanium alloy modular neck adapters. Neck adapters made of cobalt chrome alloy show significantly reduced micromotions especially in case of contaminated cone connection. With a cobalt-chromium neck the micromotions can be reduced by a factor of 3 compared to the titanium neck. The incidence of fretting corrosion was also substantially lower with the cobalt-chromium neck configuration.</p> <p>Conclusions</p> <p>Failure of modular titanium alloy neck adapters can be initiated by surface micromotions due to surface contamination or highly loaded implant components. In the present study, the patients at risk were men with an average weight over 100 kg. Modular cobalt chrome neck adapters provide higher safety compared to titanium alloy material.</p
Efficacy and Tolerability of Adjunctive Intravenous Sodium Nitroprusside Treatment for Outpatients With Schizophrenia: A Randomized Clinical Trial
Importance: Antipsychotic medications for the treatment of schizophrenia have limitations, and new treatments are needed. A prior pilot investigation suggested that adjunctive sodium nitroprusside (SNP) administered intravenously had rapid efficacy in the treatment of patients with schizophrenia.
Objective: To determine the efficacy and tolerability of intravenous SNP infused at a rate of 0.5 mug/kg/min for 4 hours in patients with schizophrenia with some degree of treatment resistance.
Design, Setting, and Participants: Multicenter, randomized, double-blind acute treatment study using a sequential parallel comparison design conducted in two 2-week phases at 4 academic medical centers beginning May 20, 2015, and ending March 31, 2017. Participants were adults 18 to 65 years of age with a diagnosis of schizophrenia as confirmed by the Structured Clinical Interview for DSM-IV, taking antipsychotic medication for at least 8 weeks, and had at least 1 failed trial of an antipsychotic medication within the past year. A total of 90 participants consented, 60 participants enrolled, and 52 participants were included in the analyses. A modified intent-to-treat analysis was used.
Interventions: Participants were randomized in a 1:1:1 ratio to 1 of 3 treatment sequences: SNP and SNP, placebo and SNP, and placebo and placebo. The SNP and SNP group received SNP in phase 1 and SNP in phase 2 for the purpose of blinding, but the data from phase 2 were not included in the results. The placebo and SNP group received placebo in phase 1 and SNP in phase 2. If there was no response to placebo in phase 1, data from phase 2 were included in the analyses. The placebo and placebo group received placebo in both phases; if there was no response to placebo in phase 1, data from phase 2 were included in the analyses.
Main Outcomes and Measures: Effectiveness of SNP compared with placebo in improving Positive and Negative Syndrome Scale (PANSS) total, positive, and negative scores across each 2-week phase.
Results: Fifty-two participants (12 women and 40 men) were included in the study. In the SNP and SNP group, the mean (SD) age was 47.1 (10.5) years. In the placebo and SNP group, the mean (SD) age was 45.9 (12.3) years. In the placebo and placebo group, the mean (SD) age was 40.4 (11.0) years. There were no significant differences between the SNP and placebo groups at baseline or in change from baseline for PANSS-total (weighted beta = -1.04; z = -0.59; P = .57), PANSS-positive (weighted beta = -0.62; z = -0.93; P = .35), or PANSS-negative (weighted beta = -0.12; z = -0.19; P = .85) scores. No significant differences in safety or tolerability measures were identified.
Conclusions and Relevance: Although intravenous SNP is well tolerated, it was not an efficacious adjunctive treatment of positive or negative symptoms of psychosis among outpatients with schizophrenia with prior history of treatment resistance.
Trial Registration: ClinicalTrials.gov identifier: NCT02164981
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