2,797 research outputs found

    Preface

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    Adjusting for COPD severity in database research: developing and validating an algorithm

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    Purpose: When comparing chronic obstructive lung disease (COPD) interventions in database research, it is important to adjust for severity. Global Initiative for Chronic Obstructive Lung Disease (GOLD) guidelines grade severity according to lung function. Most databases lack data on lung function. Previous database research has approximated COPD severity using demographics and healthcare utilization. This study aims to derive an algorithm for COPD severity using baseline data from a large respiratory trial (UPLIFT).Methods: Partial proportional odds logit models were developed for probabilities of being in GOLD stages II, III and I V. Concordance between predicted and observed stage was assessed using kappa-statistics. Models were estimated in a random selection of 2/3 of patients and validated in the remainder. The analysis was repeated in a subsample with a balanced distributio

    Statistical Evaluations of the Reproducibility and Reliability of 3-Tesla High Resolution Magnetization Transfer Brain Images: A Pilot Study on Healthy Subjects

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    Magnetization transfer imaging (MT) may have considerable promise for early detection and monitoring of subtle brain changes before they are apparent on conventional magnetic resonance images. At 3 Tesla (T), MT affords higher resolution and increased tissue contrast associated with macromolecules. The reliability and reproducibility of a new high-resolution MT strategy were assessed in brain images acquired from 9 healthy subjects. Repeated measures were taken for 12 brain regions of interest (ROIs): genu, splenium, and the left and right hemispheres of the hippocampus, caudate, putamen, thalamus, and cerebral white matter. Spearman's correlation coefficient, coefficient of variation, and intraclass correlation coefficient (ICC) were computed. Multivariate mixed-effects regression models were used to fit the mean ROI values and to test the significance of the effects due to region, subject, observer, time, and manual repetition. A sensitivity analysis of various model specifications and the corresponding ICCs was conducted. Our statistical methods may be generalized to many similar evaluative studies of the reliability and reproducibility of various imaging modalities

    Patterns of medical management of overactive bladder (OAB) and benign prostatic hyperplasia (BPH) in the United States

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    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142147/1/nau23276.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142147/2/nau23276_am.pd

    Ruthenium polypyridyl complexes and their modes of interaction with DNA : is there a correlation between these interactions and the antitumor activity of the compounds?

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    Various interaction modes between a group of six ruthenium polypyridyl complexes and DNA have been studied using a number of spectroscopic techniques. Five mononuclear species were selected with formula [Ru(tpy) L1L2](2-n)?, and one closely related dinuclear cation of formula [{Ru(apy)(tpy)}2{l-H2N(CH2)6NH2}]4?. The ligand tpy is 2,20:60,200-terpyridine and the ligand L1 is a bidentate ligand, namely, apy (2,20-azobispyridine), 2-phenylazopyridine, or 2-phenylpyridinylmethylene amine. The ligand L2 is a labile monodentate ligand, being Cl-, H2O, or CH3CN. All six species containing a labile L2 were found to be able to coordinate to the DNA model base 9-ethylguanine by 1H NMR and mass spectrometry. The dinuclear cationic species, which has no positions available for coordination to a DNA base, was studied for comparison purposes. The interactions between a selection of four representative complexes and calf-thymus DNA were studied by circular and linear dichroism. To explore a possible relation between DNA-binding ability and toxicity, all compounds were screened for anticancer activity in a variety of cancer cell lines, showing in some cases an activity which is comparable to that of cisplatin. Comparison of the details of the compound structures, their DNA binding, and their toxicity allows the exploration of structure–activity relationships that might be used to guide optimization of the activity of agents of this class of compounds

    Supporting the Changing Research Practices of Asian Studies Scholars

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    Ithaka S+R’s Research Support Services Program investigates how the research support needs of scholars vary by discipline and includes reports on history, chemistry, art history, religious studies, agriculture, and public health. In 2017-2018, Ithaka S+R examined the changing research methods and practices of Asian studies scholars conducting research through U.S. institutions. This project was undertaken collaboratively with research teams at 11 academic libraries with the goal of identifying services to better support Asian studies scholars. This report aims to provide actionable findings for the organizations, institutions, and professionals who support the research process of Asian studies scholars. One hundred and sixty-nine scholars were interviewed during the project, and Ithaka S+R sampled 50 of the resulting transcripts for the analysis presented in this report. These transcripts yielded findings in several thematic areas in which Asian studies would benefit from new or improved services, including its position within the academy, discovering and accessing information, managing research workflows, and producing outputs that reach target audiences and have the desired impact

    Transverse energy production and charged-particle multiplicity at midrapidity in various systems from sNN=7.7\sqrt{s_{NN}}=7.7 to 200 GeV

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    Measurements of midrapidity charged particle multiplicity distributions, dNch/dΡdN_{\rm ch}/d\eta, and midrapidity transverse-energy distributions, dET/dΡdE_T/d\eta, are presented for a variety of collision systems and energies. Included are distributions for Au++Au collisions at sNN=200\sqrt{s_{_{NN}}}=200, 130, 62.4, 39, 27, 19.6, 14.5, and 7.7 GeV, Cu++Cu collisions at sNN=200\sqrt{s_{_{NN}}}=200 and 62.4 GeV, Cu++Au collisions at sNN=200\sqrt{s_{_{NN}}}=200 GeV, U++U collisions at sNN=193\sqrt{s_{_{NN}}}=193 GeV, dd++Au collisions at sNN=200\sqrt{s_{_{NN}}}=200 GeV, 3^{3}He++Au collisions at sNN=200\sqrt{s_{_{NN}}}=200 GeV, and pp++pp collisions at sNN=200\sqrt{s_{_{NN}}}=200 GeV. Centrality-dependent distributions at midrapidity are presented in terms of the number of nucleon participants, NpartN_{\rm part}, and the number of constituent quark participants, NqpN_{q{\rm p}}. For all AA++AA collisions down to sNN=7.7\sqrt{s_{_{NN}}}=7.7 GeV, it is observed that the midrapidity data are better described by scaling with NqpN_{q{\rm p}} than scaling with NpartN_{\rm part}. Also presented are estimates of the Bjorken energy density, ξBJ\varepsilon_{\rm BJ}, and the ratio of dET/dΡdE_T/d\eta to dNch/dΡdN_{\rm ch}/d\eta, the latter of which is seen to be constant as a function of centrality for all systems.Comment: 706 authors, 32 pages, 20 figures, 34 tables, 2004, 2005, 2008, 2010, 2011, and 2012 data. v2 is version accepted for publication in Phys. Rev.
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