288 research outputs found

    Psychoacoustic measurement of phase and level for cross-talk cancellation using bilateral bone transducers: Comparison of methods

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    Two bone-conduction hearing aids (BCHAs) could deliver improved stereo separation using cross-talk cancellation. Sound vibrations from each BCHA would be cancelled at the contralateral cochlea by an out-of-phase signal of the same level from the ipsilateral BCHA. A method to measure the level and phase required for these cancellation signals was developed and cross-validated with an established technique that combines air- and bone-conducted sound. Three participants with normal hearing wore bone transducers (BTs) on each mastoid and insert earphones. Both BTs produced a pure tone and the level and phase were adjusted in the right BT in order to cancel all perceived sound at that ear. To cross-validate, one BT was stimulated with a pure tone and participants cancelled the resultant signal at both cochleae via adjustment of the phase and level of signals from the earphones. Participants achieved cancellation using both methods between 1.5 and 8 kHz. Levels measured with each method differed by <1 dB between 3 and 5 kHz. The phase results also corresponded well for the cancelled ear (11° mean difference) but poorly for the contralateral ear (38.4° mean difference). The first method is transferable to patients with middle-ear dysfunction, but covers a limited frequency range

    Measurements of inter-cochlear level and phase differences of bone-conducted sound

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    Bone-anchored hearing aids are a widely used method of treating conductive hearing loss, but the benefit of bilateral implantation is limited due to interaural cross-talk. The present study measured the phase and level of pure tones reaching each cochlea from a single, mastoid placed bone transducer on normal hearing participants. In principle, the technique could be used to implement a cross-talk cancellation system in those with bilateral bone conductors. The phase and level of probe tones over two insert earphones was adjusted until they canceled sound from a bone transducer (i.e., resulting in perceived silence). Testing was performed in 50-Hz steps between 0.25 and 8 kHz. Probe phase and level results were used to calculate inter-cochlear level and phase differences. The inter-cochlear phase differences of the bone-conducted sound were similar for all three participants showing a relatively linear increase between 4 and 8 kHz. The attenuation characteristics were highly variable over the frequency range as well as between participants. This variability was thought to be related to differences in skull dynamics across the ears. Repeated measurements of cancellation phase and level of the same frequency produced good consistency across sessions from the same participant

    The utility of renal ultrasonography in the diagnosis of renal colic in emergency department patients

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    Objective: Computed tomography (CT) is an imaging modality used to detect renal stones. However, there is concern about the lifetime cumulative radiation exposure attributed to CT. Ultrasonography (US) has been used to diagnose urolithiasis, thereby avoiding radiation exposure. The objective of this study was to determine the ability of US to identify renal colic patients with a low risk of requiring urologic intervention within 90 days of their initial emergency department (ED) visit. Methods: We completed a retrospective medical record review for all adult patients who underwent ED-ordered renal US for suspected urolithiasis over a 1-year period. Independent, double data extraction was performed for all imaging reports and US results were categorized as normal, suggestive of ureterolithiasis, ureteric stone seen or disease unrelated to urolithiasis. Charts were reviewed to determine how many patients underwent subsequent CT and urologic intervention. Results: Of the 817 renal US procedures ordered for suspected urolithiasis during the study period, the results of 352 (43.2%) were classified as normal, and only 2 (0.6%) of these patients required urologie intervention. The results of 177 (21.7%) renal US procedures were suggestive of ureterolithiasis. Of these, 12 (6.8%) patients required urologie intervention. Of the 241 (29.5%) patients who had a ureteric stone seen on US, 15 (6.2%) required urologie intervention. The rate of urologie intervention was significantly lower in those with normal results on US (p \u3c 0.001) than in those with abnormal results on US. Conclusion: A normal result on renal US predicts a low likelihood for urologie intervention within 90 days for adult ED patients with suspected urolithiasis

    Normal renal sonogram identifies renal colic patients at low risk for urologic intervention: A prospective cohort study

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    Introduction: Determining which patients with ureterolithiasis are likely to require urologic intervention is a common challenge in the emergency department (ED). The objective was to determine if normal renal sonogram could identify low-risk renal colic patients, who were defined as not requiring urologic intervention within 90 days of their initial ED visit and can be managed conservatively. Methods: This was a prospective cohort study involving adult patients presenting to the EDs of a tertiary care centre with suspected renal colic over a 20-month period. Renal ultrasonography (US) was performed in the diagnostic imaging department by trained ultrasonographers, and the results were categorized into four mutually exclusive groups: normal, suggestive of ureterolithiasis, visualized ureteric stone, or findings unrelated to urolithiasis. Electronic medical records were reviewed to determine if patients received urologic intervention within 90 days of their ED visit. Results: Of 610 patients enrolled, 341 (55.9%) had US for suspected renal colic. Of those, 105 (30.8%) were classified as normal; none of these patients underwent urologic intervention within 90 days of their ED visit. Ninety (26.4%) US results were classified as suggestive, and nine (10%) patients received urologic intervention. A total of 139 (40.8%) US results were classified as visualized ureteric stone, and 34 (24.5%) patients had urologic intervention. Seven (2.1%) US results were classified as findings unrelated to urolithiasis, and none of these patients required urologic intervention. The rate of urologic intervention was significantly lower in those with normal US results (p \u3c 0.001) than in those with abnormal findings. Conclusion: A normal renal sonogram predicts a low likelihood for urologic intervention within 90 days for adult ED patients with suspected renal colic

    A protocol for investigation of the effects of outdoor air pollution on stroke incidence, phenotypes and survival using the South London Stroke Register.

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    Stroke is a major cause of death and disability. About 5.3 million people die every year from stroke worldwide with over 9 million people surviving at any one time after suffering a stroke. About 1 in 4 men and 1 in 5 women aged 45 years will suffer a stroke if they live to their 85th year. It is estimated that by 2023 there will be an absolute increase in the number of people experiencing a first ever stroke of about 30% compared with 1983. In the UK, stroke is the third commonest cause of death and the most common cause of adult physical disability and consumes 5% of the health and social services budget. Stroke is assuming strategic public health importance because of increased awareness in society, an ageing population and emerging new treatments. It is an NHS health service and research priority, being identified as a target in Our Healthier Nation and the NSF for Older People for prevention and risk factor control and in the NHS Plan as a disease requiring intermediate care planning and reduction in inequalities of care. Whilst a number of risk factors for stroke are well known (e.g. increasing age, ethnicity, socioeconomic deprivation, hypertension), the potential importance of outdoor air pollution as a modifiable risk factor is much less well recognised. This is because studies to date are inconclusive or have methodological limitations. In Sheffield, we estimated that 11% of stroke deaths may be linked to current levels of outdoor air pollution and this high figure is explained by the fact that so many people are exposed to air pollution.We plan to study the effects of outdoor air pollution on stroke using a series of epidemiological (i.e. population based) studies. The purpose of this project is: to examine if short term increases in pollution can trigger a stroke in susceptible individuals, to investigate if the occurrence of stroke is higher amongst people living in more polluted areas (which would be explained by a combination of exposure to short term increases and longer term exposure to higher pollution levels), and to see if people living in more polluted areas have reduced survival following their stroke. We will use geographical information systems, robust statistical methods and powerful grid computing facilities to link and analyse the data. The datasets we will use are the South London Stroke Register database, daily monitored pollution data from national monitoring networks and modelled pollution data for London from the Greater London Authority. The South London Stroke Register records information on all patients who suffer a stroke ("incident" cases) living within a defined area. This stroke incidence dataset offers major advantages over previous studies examining the effects of pollution on hospital admissions and mortality, as not all patients with stroke are admitted or die and there may be a delay between the onset of stroke and admission or death. In addition, it contains other useful information, particularly the type of stroke people have suffered. Air pollution is a potentially modifiable risk factor for stroke. This study will provide robust population level evidence regarding the effects of outdoor air pollution on stroke. If it confirms the link, it will suggest to policy-makers at national and international levels that targeting policy interventions at high pollution areas may be a feasible option for stroke prevention

    Participant experiences of attending a community CBT workshop for insomnia: A qualitative six-year follow-up

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    Objective/Background: Our aim was to qualitatively explore the experiences of people who attended a one-day sleep workshop six years previously. Participants: Of the 95 people who originally attended the workshop and a three-month follow-up, 14 individuals (mean age = 63.6 years) participated. Methods: Semi-structured interviews were used to explore: participants’ experiences of insomnia since the workshop, memories of the techniques and information provided and the perceived impact of the workshop on their lives. Qualitative data were analyzed using the principles of Framework Analysis. Results: Interviews produced rich accounts of attributions of changes in sleep, the application of taught strategies and general experiences of the workshop. Conclusions: This research highlights which aspects of a large-scale intervention may be most helpful for individuals experiencing sleep difficulties and what factors may contribute to changes in sleep over time

    Real-world outcomes of sipuleucel-T treatment in PROCEED, a prospective registry of men with metastatic castration-resistant prostate cancer.

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    BackgroundThe large registry, PROVENGE Registry for the Observation, Collection, and Evaluation of Experience Data (PROCEED)(NCT01306890), evaluated sipuleucel-T immunotherapy for asymptomatic/minimally symptomatic metastatic castration-resistant prostate cancer (mCRPC).MethodsPROCEED enrolled patients with mCRPC receiving 3 biweekly sipuleucel-T infusions. Assessments included overall survival (OS), serious adverse events (SAEs), cerebrovascular events (CVEs), and anticancer interventions (ACIs). Follow-up was for ≥3&nbsp;years or until death or study withdrawal.ResultsIn 2011-2017, 1976 patients were followed for 46.6&nbsp;months (median). The median age was 72&nbsp;years, and the baseline median prostate-specific antigen level was 15.0&nbsp;ng/mL; 86.7% were white, and 11.6% were African American. Among the patients, 1902 had 1 or more sipuleucel-T infusions. The median OS was 30.7&nbsp;months (95% confidence interval [CI], 28.6-32.2&nbsp;months). Known prognostic factors were independently associated with OS in a multivariable analysis. Among the 1255 patients who died, 964 (76.8%) died of prostate cancer (PC) progression. The median time from the first infusion to PC death was 42.7&nbsp;months (95% CI, 39.4-46.2&nbsp;months). The incidence of sipuleucel-T-related SAEs was 3.9%. The incidence of CVEs was 2.8%, and the rate per 100 person-years was 1.2 (95% CI, 0.9-1.6). The CVE incidence among 11,972 patients with mCRPC from the Surveillance, Epidemiology, and End Results-Medicare database was 2.8%; the rate per 100 person-years was 1.5 (95% CI, 1.4-1.7). One or more ACIs (abiraterone, enzalutamide, docetaxel, cabazitaxel, or radium 223) were received by 77.1% of the patients after sipuleucel-T; 32.5% and 17.4% of the patients experienced 1- and 2-year treatment-free intervals, respectively.ConclusionsPROCEED provides contemporary survival data for sipuleucel-T-treated men in a real-world setting of new life-prolonging agents, which will be useful in discussing treatment options with patients and in powering future trials with sipuleucel-T. The safety and tolerability of sipuleucel-T in PROCEED were consistent with previous findings

    KELT-6b: A P~7.9 d Hot Saturn Transiting a Metal-Poor Star with a Long-Period Companion

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    We report the discovery of KELT-6b, a mildly-inflated Saturn-mass planet transiting a metal-poor host. The initial transit signal was identified in KELT-North survey data, and the planetary nature of the occulter was established using a combination of follow-up photometry, high-resolution imaging, high-resolution spectroscopy, and precise radial velocity measurements. The fiducial model from a global analysis including constraints from isochrones indicates that the V=10.38 host star (BD+31 2447) is a mildly evolved, late-F star with T_eff=6102 \pm 43 K, log(g_*)=4.07_{-0.07}^{+0.04} and [Fe/H]=-0.28 \pm 0.04, with an inferred mass M_*=1.09 \pm 0.04 M_sun and radius R_star=1.58_{-0.09}^{+0.16} R_sun. The planetary companion has mass M_P=0.43 \pm 0.05 M_J, radius R_P=1.19_{-0.08}^{+0.13} R_J, surface gravity log(g_P)=2.86_{-0.08}^{+0.06}, and density rho_P=0.31_{-0.08}^{+0.07} g~cm^{-3}. The planet is on an orbit with semimajor axis a=0.079 \pm 0.001 AU and eccentricity e=0.22_{-0.10}^{+0.12}, which is roughly consistent with circular, and has ephemeris of T_c(BJD_TDB)=2456347.79679 \pm 0.00036 and P=7.845631 \pm 0.000046 d. Equally plausible fits that employ empirical constraints on the host star parameters rather than isochrones yield a larger planet mass and radius by ~4-7%. KELT-6b has surface gravity and incident flux similar to HD209458b, but orbits a host that is more metal poor than HD209458 by ~0.3 dex. Thus, the KELT-6 system offers an opportunity to perform a comparative measurement of two similar planets in similar environments around stars of very different metallicities. The precise radial velocity data also reveal an acceleration indicative of a longer-period third body in the system, although the companion is not detected in Keck adaptive optics images.Comment: Published in AJ, 17 pages, 15 figures, 6 table

    KELT-8b: A highly inflated transiting hot Jupiter and a new technique for extracting high-precision radial velocities from noisy spectra

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    We announce the discovery of a highly inflated transiting hot Jupiter discovered by the KELT-North survey. A global analysis including constraints from isochrones indicates that the V = 10.8 host star (HD 343246) is a mildly evolved, G dwarf with Teff=575455+54T_{\rm eff} = 5754_{-55}^{+54} K, logg=4.0780.054+0.049\log{g} = 4.078_{-0.054}^{+0.049}, [Fe/H]=0.272±0.038[Fe/H] = 0.272\pm0.038, an inferred mass M=1.2110.066+0.078M_{*}=1.211_{-0.066}^{+0.078} M_{\odot}, and radius R=1.670.12+0.14R_{*}=1.67_{-0.12}^{+0.14} R_{\odot}. The planetary companion has mass MP=0.8670.061+0.065M_P = 0.867_{-0.061}^{+0.065} MJM_{J}, radius RP=1.860.16+0.18R_P = 1.86_{-0.16}^{+0.18} RJR_{J}, surface gravity loggP=2.7930.075+0.072\log{g_{P}} = 2.793_{-0.075}^{+0.072}, and density ρP=0.1670.038+0.047\rho_P = 0.167_{-0.038}^{+0.047} g cm3^{-3}. The planet is on a roughly circular orbit with semimajor axis a=0.045710.00084+0.00096a = 0.04571_{-0.00084}^{+0.00096} AU and eccentricity e=0.0350.025+0.050e = 0.035_{-0.025}^{+0.050}. The best-fit linear ephemeris is T0=2456883.4803±0.0007T_0 = 2456883.4803 \pm 0.0007 BJDTDB_{\rm TDB} and P=3.24406±0.00016P = 3.24406 \pm 0.00016 days. This planet is one of the most inflated of all known transiting exoplanets, making it one of the few members of a class of extremely low density, highly-irradiated gas giants. The low stellar logg\log{g} and large implied radius are supported by stellar density constraints from follow-up light curves, plus an evolutionary and space motion analysis. We also develop a new technique to extract high precision radial velocities from noisy spectra that reduces the observing time needed to confirm transiting planet candidates. This planet boasts deep transits of a bright star, a large inferred atmospheric scale height, and a high equilibrium temperature of Teq=167555+61T_{eq}=1675^{+61}_{-55} K, assuming zero albedo and perfect heat redistribution, making it one of the best targets for future atmospheric characterization studies.Comment: Submitted to ApJ, feedback is welcom
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