86 research outputs found
Use of hospitalisation history (lookback) to determine prevalence of chronic diseases: impact on modelling of risk factors for haemorrhage in pregnancy
<p>Abstract</p> <p>Background</p> <p>Concern about the completeness of comorbidity information in hospital records has been raised as a limitation of using hospital discharge data for research. The aim of this study is to assess the impact of additional comorbidity information from prior hospital admissions on estimation of prevalence and modelling of risk factors for obstetric haemorrhage.</p> <p>Methods</p> <p>A range of chronic disease prevalence for 53,438 women who had their first birth in New South Wales (NSW), Australia, 2005-2006, were ascertained for up to five years prior to the birth admission (for pregnancy, 2-, 3-, 4- and 5-year periods) and obstetric haemorrhage was identified from maternal hospital records for 2005 and 2006.</p> <p>Results</p> <p>The ascertainment of chronic disease prevalence increased with increasing length of lookback. However, the rate of the increase was slower after 2 to 3 years than for the more recent periods. The effect size of chronic diseases on obstetric haemorrhage risk decreased with the increased case ascertainment associated with longer lookback. Furthermore, longer lookback did not improve the predictive capacity (C-statistic: 0.624) of a model that was based only on the birth admission records.</p> <p>Conclusions</p> <p>Longer ascertainment periods resulted in improved identification of chronic disease history among pregnant women, but the additional information from prior admissions did little to improve the modelling of risk factors for obstetric haemorrhage.</p
Fifty-Year Fate and Impact of General Medical Journals
Background: Influential medical journals shape medical science and practice and their prestige is usually appraised by citation impact metrics, such as the journal impact factor. However, how permanent are medical journals and how stable is their impact over time? Methods and Results: We evaluated what happened to general medical journals that were publishing papers half a century ago, in 1959. Data were retrieved from ISI Web of Science for citations and PubMed (Journals function) for journal history. Of 27 eligible journals publishing in 1959, 4 have stopped circulation (including two of the most prestigious journals in 1959) and another 7 changed name between 1959 and 2009. Only 6 of these 27 journals have been published continuously with their initial name since they started circulation. The citation impact of papers published in 1959 gives a very different picture from the current journal impact factor; the correlation between the two is non-significant and very close to zero. Only 13 of the 5,223 papers published in 1959 received at least 5 citations in 2009. Conclusions: Journals are more permanent entities than single papers, but they are also subject to major change and their relative prominence can change markedly over time
Targeted LC–MS derivatization for aldehydes and carboxylic acids with a new derivatization agent 4-APEBA
Based on the template of a recently introduced derivatization reagent for aldehydes, 4-(2-(trimethylammonio)ethoxy)benzeneaminium dibromide (4-APC), a new derivatization agent was designed with additional features for the analysis and screening of biomarkers of lipid peroxidation. The new derivatization reagent, 4-(2-((4-bromophenethyl)dimethylammonio)ethoxy)benzenaminium dibromide (4-APEBA) contains a bromophenethyl group to incorporate an isotopic signature to the derivatives and to add additional fragmentation identifiers, collectively enhancing the abilities for detection and screening of unknown aldehydes. Derivatization can be achieved under mild conditions (pH 5.7, 10 °C). By changing the secondary reagent (1-ethyl-3-(3-dimethylaminopropyl) carbodiimide instead of sodium cyanoborohydride), 4-APEBA is also applicable to the selective derivatization of carboxylic acids. Synthesis of the new label, exploration of the derivatization conditions, characterization of the fragmentation of the aldehyde and carboxylic acid derivatives in MS/MS, and preliminary applications of the labeling strategy for the analysis of aldehydes in urine and plasma are described
Measurements of the branching fraction and CP-violation asymmetries in B-0 -> f(0)(980)K-S(0)
We present measurements of the branching fraction and CP-violating asymmetries in the decay B-0-->f(0)(980)K-S(0). The results are obtained from a data sample of 123x10(6) Y(4S)-->B (B) over bar decays. From a time-dependent maximum likelihood fit, we measure the branching fraction B(B-0-->f(0)(980)(-->pi(+)pi(-))K-0)=(6.0+/-0.9+/-0.6+/-1.2)x10(-6), the mixing-induced CP violation parameter S=-1.62(-0.51)(+0.56)+/-0.09+/-0.04, and the direct CP violation parameter C=0.27+/-0.36+/-0.10+/-0.07, where the first errors are statistical, the second systematic, and the third due to model uncertainties. We measure the f(0)(980) mass and width to be m(f0)(980)=(980.6+/-4.1+/-0.5+/-4.0) MeV/c(2) and Gamma(f0)(980)=(43(-9)(+12)+/-3+/-9) MeV/c(2), respectively
Search for radiative penguin decays B+->rho(+)gamma, B-0 ->rho(0)gamma, and B-0 ->omega gamma
A search for the decays B-->rho(770)gamma and B-0-->omega(782)gamma is performed on a sample of 211x10(6) Y(4S)-->B (B) over bar events collected by the BABAR detector at the SLAC PEP-II asymmetric-energy e(+)e(-) storage ring. No evidence for the decays is seen. We set the following limits on the individual branching fractions: B(B+-->rho(+)gamma)rho(0)gamma)omegagamma)(rho/omega)gamma]<1.2x10(-6), from which we determine a constraint on the ratio of Cabibbo-Kobayashi-Maskawa matrix elements |V-td|/|V-ts|
Search for the rare leptonic decay B-->tau(-)nu(tau)
We present a search for the decay B- -> tau(-)(tau) in a sample of 88.9 x 10(6) B (B) over bar pairs recorded with the BABAR detector at the Stanford Linear Accelerator Center B factory. One of the two B mesons from the Upsilon(4S) is reconstructed in a hadronic or a semileptonic final state, and the decay products of the other B in the event are analyzed for consistency with a B- -> tau(-)(tau) decay. We find no evidence of a signal and set an upper limit on the branching fraction of B((B) over bar -> tau(-)(tau)) < 4.2 x 10(-4) at the 90% confidence level
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