6,779 research outputs found

    The Efficacy of PET Staging for Small-Cell Lung Cancer: A Systematic Review and Cost Analysis in the Australian Setting

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    IntroductionThis study aimed to establish from the published literature the efficacy of a positron emission tomography (PET)-based strategy for the staging of small-cell lung cancer compared to conventional methods, the potential impact on patient management and outcomes, and cost implications for the Australian health system.MethodsEMBASE, Current Contents, PubMed, and OVID, databases were searched using relevant search terms. Reference lists of identified studies were examined for additional pertinent papers. Literature review identified 22 relevant studies containing data for 1663 patients. Studies were evaluated regarding the adequacy of pathological or clinical correlation of imaging findings. Efficacy of PET-staging was analyzed. The Medicare benefits schedule was used to compare costs of the two strategies.ResultsPublished data confirm that PET staging has a sensitivity approaching 100% and specificity exceeding 90%. Data suggest that compared to conventional staging, PET can alter management (including radiotherapy portal changes) in at least 28% of patients, can result in the addition of life-prolonging radiotherapy in 6%, and avert unnecessary radiotherapy with associated toxicity in 9%. PET-based staging costs 1603 Australian dollars (AUD) and conventional staging 1610 AUD per patient. An additional 540,354 AUD may be saved annually through avoidance of unnecessary radiotherapy.ConclusionsPET-based staging seems superior to conventional staging, and can significantly alter patient management particularly with regard to the inclusion, omission, and portal design of radiotherapy. The initial costs of the two strategies do not seem significantly different. PET may ultimately reduce healthcare costs through avoidance of inappropriate thoracic radiotherapy. The major advantages of PET-staging may, however, lie in averting unnecessary toxicity and in the appropriate addition of thoracic radiotherapy with potential survival gains

    Matrix isolation as a tool for studying interstellar chemical reactions

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    Since the identification of the OH radical as an interstellar species, over 50 molecular species were identified as interstellar denizens. While identification of new species appears straightforward, an explanation for their mechanisms of formation is not. Most astronomers concede that large bodies like interstellar dust grains are necessary for adsorption of molecules and their energies of reactions, but many of the mechanistic steps are unknown and speculative. It is proposed that data from matrix isolation experiments involving the reactions of refractory materials (especially C, Si, and Fe atoms and clusters) with small molecules (mainly H2, H2O, CO, CO2) are particularly applicable to explaining mechanistic details of likely interstellar chemical reactions. In many cases, matrix isolation techniques are the sole method of studying such reactions; also in many cases, complexations and bond rearrangements yield molecules never before observed. The study of these reactions thus provides a logical basis for the mechanisms of interstellar reactions. A list of reactions is presented that would simulate interstellar chemical reactions. These reactions were studied using FTIR-matrix isolation techniques

    Longitudinal Assessment of Older Drivers in a DMV Setting

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    A brief battery of functional assessments designed to detect crash riskamong older drivers was developed and evaluated initially in 1999 in Marylandmotor vehicle licensing sites following the routine vision screening exam. Thisbattery contained a number of cognitive tests (e.g., UFOV® subtest 2, the closuresubtest of the Motor Free Visual Perception Test (MVPT), Trails A and B, cuedrecall, delayed recall), and several physical measures (e.g., Rapid Pace Walk,Head and Neck Rotation, Foot Tap, Arm Reach). Older adults (N=4,173; meanage = 69 years) were approached by the staff after license renewal and asked tohelp evaluate the brief battery. Of the 4,173 older adults approached at the fieldsites, 2,114 individuals 55-96 years of age participated. Subsequently, the originalsample of 2,114 participants was invited to come in once again, during their fiveyearlicense renewal cycle, and the functional tests were administered once again.To date, 939 individuals have completed the second screening evaluation. Anexamination of the crash data from the interval between assessments for theseindividuals indicates that the same cognitive measures are predictive of at-faultcrashes. Furthermore, approximately 10% of those passing the assessment in 1999are now failing the assessment in 2004. Performance-based cognitive measuresare predictive of future at-fault motor vehicle collisions among older adults.Cognitive performance, in particular, is a salient predictor of subsequent crashinvolvement among older adults. High-risk older drivers can be identified throughbrief, performance-based measures administered in a DMV setting

    Computed tomographic atlas for the new international lymph node map for lung cancer: A radiation oncologist perspective

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    International audiencePurpose : To develop a reproducible definition for each mediastinal lymph node station based on the new TNM classification for lung cancer. Methods and Materials : This paper proposes an atlas using the new international lymph node map used in the seventh edition of the TNM classification for lung cancer. Four radiation oncologists and 1 diagnostic radiologist were involved in the project to put forward a reproducible radiologic description for the lung lymph node stations.Results : The International Association for the Study of Lung Cancer lymph node definitions for stations 1 to 11 have been described and illustrated on axial computed tomographic scan images using a certified radiotherapy planning system. Conclusions : This atlas will assist both diagnostic radiologists and radiation oncologists in accurately defining the lymph node stations on computed tomographic scan in patients diagnosed with lung cancer

    Electron Affinity Calculations for Thioethers

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    Previous work indicated that polyphenyl thioethers possessed chemical properties, related to their electron affinities, which could allow them to function as vapor phase lubricants (VPL). Indeed, preliminary tribological tests revealed that the thioethers could function as vapor phase lubricants but not over a wide temperature and hertzian pressure range. Increasing the electron affinity of the thioethers may improve their VPL properties over this range. Adding a substituent group to the thioether will alter its electron affinity in many cases. Molecular orbital calculations were undertaken to determine the effect of five different substituent groups on the electron affinity of polyphenyl thioethers. It was found that the NO2, F, and I groups increased the thioethers electron affinity by the greatest amount. Future work will involve the addition of these groups to the thioethers followed by tribological testing to assess their VPL properties

    Evaluation of vaccination strategies for SIR epidemics on random networks incorporating household structure

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    This paper is concerned with the analysis of vaccination strategies in a stochastic SIR (susceptible → infected → removed) model for the spread of an epidemic amongst a population of individuals with a random network of social contacts that is also partitioned into households. Under various vaccine action models, we consider both household-based vaccination schemes, in which the way in which individuals are chosen for vaccination depends on the size of the households in which they reside, and acquaintance vaccination, which targets individuals of high degree in the social network. For both types of vaccination scheme, assuming a large population with few initial infectives, we derive a threshold parameter which determines whether or not a large outbreak can occur and also the probability and fraction of the population infected by such an outbreak. The performance of these schemes is studied numerically, focusing on the influence of the household size distribution and the degree distribution of the social network. We find that acquaintance vaccination can significantly outperform the best household-based scheme if the degree distribution of the social network is heavy-tailed. For household-based schemes, when the vaccine coverage is insufficient to prevent a major outbreak and the vaccine is imperfect, we find situations in which both the probability and size of a major outbreak under the scheme which minimises the threshold parameter are \emph{larger} than in the scheme which maximises the threshold parameter

    Symmetries and Asymmetries of B -> K* mu+ mu- Decays in the Standard Model and Beyond

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    The rare decay B -> K* (-> K pi) mu+ mu- is regarded as one of the crucial channels for B physics as the polarization of the K* allows a precise angular reconstruction resulting in many observables that offer new important tests of the Standard Model and its extensions. These angular observables can be expressed in terms of CP-conserving and CP-violating quantities which we study in terms of the full form factors calculated from QCD sum rules on the light-cone, including QCD factorization corrections. We investigate all observables in the context of the Standard Model and various New Physics models, in particular the Littlest Higgs model with T-parity and various MSSM scenarios, identifying those observables with small to moderate dependence on hadronic quantities and large impact of New Physics. One important result of our studies is that new CP-violating phases will produce clean signals in CP-violating asymmetries. We also identify a number of correlations between various observables which will allow a clear distinction between different New Physics scenarios.Comment: 56 pages, 18 figures, 14 tables. v5: Missing factor in eqs. (3.31-32) and fig. 6 corrected. Minor misprints in eq. (2.10) and table A corrected. Conclusions unchange

    Predicting Driving Performance in Older Adults with the Useful Field of View Test: A Meta-Analysis

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    This investigation examines the Useful Field of View (specifically theUFOV® test), as a predictor of objective measures of driving performance.PubMed and PsycInfo databases were searched to retrieve eight independentstudies reporting bivariate relationships between the UFOV® test and drivingmeasures (driving simulator performance, state-recorded crashes, and on-roaddriving). Cumulative meta-analysis techniques were used to examine thepredictive utility of the test, to determine whether the effect size was stable acrossstudies, and to assess whether a sufficient number of studies have been conductedto conclude that the test is an effective predictor of driving competence. Resultsshowed that the study samples could have been drawn from the same population.The weighted mean effect size across all studies revealed a large effect, Cohen’sd=0.945, with poorer UFOV® test performance associated with negative drivingoutcomes. This relationship was robust across multiple indices of drivingperformance and several research laboratories. A concrete measure of sufficiencyrevealed that an additional 513 studies averaging a null result must be conductedto bring the p-value for the cumulative effect size to greater than .05. Thisconvergence of evidence across different points in time and different researchteams confirms the importance of the UFOV® assessment as a valid and reliableindex of driving performance and safety. Corroborating this finding, a recent largefield study in Maryland has further established the UFOV® test as a usefulscreening instrument to identify at-risk older drivers. Taken together, thesefindings could have far-reaching implications for public policy
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