2,544 research outputs found
Science Models as Value-Added Services for Scholarly Information Systems
The paper introduces scholarly Information Retrieval (IR) as a further
dimension that should be considered in the science modeling debate. The IR use
case is seen as a validation model of the adequacy of science models in
representing and predicting structure and dynamics in science. Particular
conceptualizations of scholarly activity and structures in science are used as
value-added search services to improve retrieval quality: a co-word model
depicting the cognitive structure of a field (used for query expansion), the
Bradford law of information concentration, and a model of co-authorship
networks (both used for re-ranking search results). An evaluation of the
retrieval quality when science model driven services are used turned out that
the models proposed actually provide beneficial effects to retrieval quality.
From an IR perspective, the models studied are therefore verified as expressive
conceptualizations of central phenomena in science. Thus, it could be shown
that the IR perspective can significantly contribute to a better understanding
of scholarly structures and activities.Comment: 26 pages, to appear in Scientometric
Validation of test performance characteristics and minimal clinically important difference of the 6-minute walk test in patients with idiopathic pulmonary fibrosis
SummaryBackgroundThe 6-minute walk test distance (6MWD) has been shown to be a valid and responsive outcome measure in patients with idiopathic pulmonary fibrosis (IPF). The analyses were based, however, on a single phase 3 trial and require validation in an independent cohort.ObjectiveTo confirm the performance characteristics and estimates of minimal clinically important difference (MCID) of 6MWD in an independent cohort of patients with IPF.MethodsPatients randomized to placebo in the phase 3 CAPACITY trials who had a baseline 6MWD measurement were included in these analyses. The 6MWD and other functional parameters (lung function, dyspnea, and health-related quality of life) were measured at baseline and 24-week intervals. Validity and responsiveness were examined using Spearman correlation coefficients. The MCID was estimated using distribution- and anchor-based methods.ResultsThe analysis comprised 338 patients. Baseline 6MWD was significantly correlated with lung function measures, patient-reported outcomes, and quality-of-life measures (validity). Compared with baseline 6MWD, change in 6MWD (responsiveness) showed stronger correlations with change in lung function parameters and quality-of-life measures. Dyspnea measured by the University of California San Diego Shortness of Breath Questionnaire showed the strongest correlations with 6MWD (baseline: coefficient â0.35; 48-week change: coefficient â0.37; both p < 0.001). The distribution-based analyses of MCID using standard error of measurement yielded an MCID of 37 m, and distribution-based analyses by effect size resulted in 29.2 m. The MCID by anchor-based analysis using criterion referencing (health events of hospitalization or death) was 21.7 m.ConclusionsThe 6MWD is a valid and responsive clinical endpoint, which provides objective and clinically meaningful information regarding functional status and near-term prognosis. These results confirm previous findings in an independent cohort of patients with IPF
200 mm Sensor Development Using Bonded Wafers
Sensors fabricated from high resistivity, float zone, silicon material have
been the basis of vertex detectors and trackers for the last 30 years. The
areas of these devices have increased from a few square cm to for
the existing CMS tracker. High Luminosity Large Hadron Collider (HL-LHC), CMS
and ATLAS tracker upgrades will each require more than of silicon
and the CMS High Granularity Calorimeter (HGCAL) will require more than $600\
m^2200 mm$ wafers using wafer bonding technology. Results of development runs
with float zone, Silicon-on-Insulator and Silicon-Silicon bonded wafer
technologies are reported.Comment: 11 page
Biochemical parameters of silver catfish (Rhamdia quelen) after transport with eugenol or essential oil of Lippia alba added to the water
The transport of live fish is a routine practice in aquaculture and constitutes a considerable source of stress to the animals. The addition of anesthetic to the water used for fish transport can prevent or mitigate the deleterious effects of transport stress. This study investigated the effects of the addition of eugenol (EUG) (1.5 or 3.0 mu L L-1) and essential oil of Lippia alba (EOL) (10 or 20 mu L L-1) on metabolic parameters (glycogen, lactate and total protein levels) in liver and muscle, acetylcholinesterase activity (AChE) in muscle and brain, and the levels of protein carbonyl (PC), thiobarbituric acid reactive substances (TBARS) and nonprotein thiol groups (NPSH) and activity of glutathione-S-transferase in the liver of silver catfish (Rhamdia quelen; Quoy and Gaimard, 1824) transported for four hours in plastic bags (loading density of 169.2 g L-1). The addition of various concentrations of EUG (1.5 or 3.0 mu L L-1) and EOL (10 or 20 mu L L-1) to the transport water is advisable for the transportation of silver catfish, since both concentrations of these substances increased the levels of NPSH antioxidant and decreased the TBARS levels in the liver. In addition, the lower liver levels of glycogen and lactate in these groups and lower AChE activity in the brain (EOL 10 or 20 mu L L-1) compared to the control group indicate that the energetic metabolism and neurotransmission were lower after administration of anesthetics, contributing to the maintenance of homeostasis and sedation status.Fundacao de Amparo a Pesquisa do Estado do Rio Grande do Sul (FAPERGS/PRONEX) [10/0016-8]; Conselho Nacional de Pesquisa e Desenvolvimento Cientifico (CNPq) [470964/2009-0]; Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES); CNPqinfo:eu-repo/semantics/publishedVersio
DNA replication stress restricts ribosomal DNA copy number
Ribosomal RNAs (rRNAs) in budding yeast are encoded by ~100â200 repeats of a 9.1kb sequence arranged in tandem on chromosome XII, the ribosomal DNA (rDNA) locus. Copy number of rDNA repeat units in eukaryotic cells is maintained far in excess of the requirement for ribosome biogenesis. Despite the importance of the repeats for both ribosomal and non-ribosomal functions, it is currently not known how ânormalâ copy number is determined or maintained. To identify essential genes involved in the maintenance of rDNA copy number, we developed a droplet digital PCR based assay to measure rDNA copy number in yeast and used it to screen a yeast conditional temperature-sensitive mutant collection of essential genes. Our screen revealed that low rDNA copy number is associated with compromised DNA replication. Further, subculturing yeast under two separate conditions of DNA replication stress selected for a contraction of the rDNA array independent of the replication fork blocking protein, Fob1. Interestingly, cells with a contracted array grew better than their counterparts with normal copy number under conditions of DNA replication stress. Our data indicate that DNA replication stresses select for a smaller rDNA array. We speculate that this liberates scarce replication factors for use by the rest of the genome, which in turn helps cells complete DNA replication and continue to propagate. Interestingly, tumors from mini chromosome maintenance 2 (MCM2)-deficient mice also show a loss of rDNA repeats. Our data suggest that a reduction in rDNA copy number may indicate a history of DNA replication stress, and that rDNA array size could serve as a diagnostic marker for replication stress. Taken together, these data begin to suggest the selective pressures that combine to yield a ânormalâ rDNA copy number
MINERvA neutrino detector response measured with test beam data
The MINERvA collaboration operated a scaled-down replica of the solid
scintillator tracking and sampling calorimeter regions of the MINERvA detector
in a hadron test beam at the Fermilab Test Beam Facility. This article reports
measurements with samples of protons, pions, and electrons from 0.35 to 2.0
GeV/c momentum. The calorimetric response to protons, pions, and electrons are
obtained from these data. A measurement of the parameter in Birks' law and an
estimate of the tracking efficiency are extracted from the proton sample.
Overall the data are well described by a Geant4-based Monte Carlo simulation of
the detector and particle interactions with agreements better than 4%, though
some features of the data are not precisely modeled. These measurements are
used to tune the MINERvA detector simulation and evaluate systematic
uncertainties in support of the MINERvA neutrino cross section measurement
program.Comment: as accepted by NIM
Expression of UDP-glucuronosyltransferase 1A4 in human placenta at term
The placenta contains a large variety of metabolizing enzymes, among them UDP-glucuronosyltransferase (UGT). Several UGT2B isozymes have so far been detected in human placenta, but little is known on placental expression of UGT1A isozymes. The antiepileptic drug lamotrigine (LTG) is a UGT1A4-substrate, and its serum concentration falls by over 50% during pregnancy, leading to impaired seizure control. The placenta may be involved in this. Microsomes from term placentas of 4 LTG-users and 10 healthy control subjects were prepared. Western blot analysis detected UGT1A proteins in all placentas. The presence of UGT1A4 in placenta from LTG users was confirmed with UGT1A4 commercial standard and a specific UGT1A4 primary antibody. Since LTG is primarily metabolized by UGT1A4 and this isozyme is shown to be present in placenta at term, it may be hypothesized that the placenta is involved in the fall of LTG serum concentrations during pregnancy
Consensus Analysis of Whole Transcriptome Profiles from Two Breast Cancer Patient Cohorts Reveals Long Non-Coding RNAs Associated with Intrinsic Subtype and the Tumour Microenvironment.
Long non-coding RNAs (lncRNAs) are emerging as crucial regulators of cellular processes and diseases such as cancer; however, their functions remain poorly characterised. Several studies have demonstrated that lncRNAs are typically disease and tumour subtype specific, particularly in breast cancer where lncRNA expression alone is sufficient to discriminate samples based on hormone status and molecular intrinsic subtype. However, little attempt has been made to assess the reproducibility of lncRNA signatures across more than one dataset. In this work, we derive consensus lncRNA signatures indicative of breast cancer subtype based on two clinical RNA-Seq datasets: the Utah Breast Cancer Study and The Cancer Genome Atlas, through integration of differential expression and hypothesis-free clustering analyses. The most consistent signature is associated with breast cancers of the basal-like subtype, leading us to generate a putative set of six lncRNA basal-like breast cancer markers, at least two of which may have a role in cis-regulation of known poor prognosis markers. Through in silico functional characterization of individual signatures and integration of expression data from pre-clinical cancer models, we discover that discordance between signatures derived from different clinical cohorts can arise from the strong influence of non-cancerous cells in tumour samples. As a consequence, we identify nine lncRNAs putatively associated with breast cancer associated fibroblasts, or the immune response. Overall, our study establishes the confounding effects of tumour purity on lncRNA signature derivation, and generates several novel hypotheses on the role of lncRNAs in basal-like breast cancers and the tumour microenvironment
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