4,606 research outputs found

    Using Large Institutional or National Databases to Evaluate Prostate Cancer Outcomes and Patterns of Care: Possibilities and Limitations

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    Prostate cancer is the most common non–skin-related cancer in men. With advances in technology, the care and treatment for men with this disease continues to become more complex. Large databases offer researchers a unique opportunity to conduct prostate cancer research in various areas, and provide important information that helps patients and providers determine prognosis after treatment. Furthermore, the studies using these databases may provide information on how side effects from various treatments can affect one's quality of life. Finally, information from these datasets can help to identify factors that determine why patients receive the treatments they do. Despite this, these databases are not without limitations. In this review, we discuss various available, national, multicenter, and institutional databases in the context of prostate cancer research, citing numerous important studies that have impacted on our understanding of prostate cancer outcomes

    Direct observation of a hypersonic band gap in two-dimensional single crystalline phononic structures

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    Brillouin light scattering is employed to record the phonon dispersion relation of two-dimensional (2D) hypersonic phononic crystals with square lattice plane group p4mm symmetry. The samples are single crystalline arrays of cylindrical holes with a lattice constant of 750 nm and 35% porosity patterned in epoxy using interference lithography. The dispersion relation reveals the presence of a phononic band gap between 1.21 and 1.57 GHz at the edge of the first Brillouin zone for elastic waves propagating along the [10] direction and conclusively demonstrates a band gap in a single crystalline 2D polymer based phononic structure at hypersonic frequencies.open312

    Determination of vancomycin and gentamicin clearance in an in vitro, closed loop dialysis system

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    Background\ud The purpose of this study was to evaluate the feasibility of utilizing an in-vitro, closed loop hemodialysis system as a method to assess drug clearance. Secondarily, this study tested the influence of variables (blood flow rate, dialysate flow rate, and type of filter) in the hemodialysis procedure on the clearance of vancomycin and gentamicin.\ud \ud Methods\ud An in-vitro, closed loop hemodialysis system was constructed. The vancomycin (30 mg/L) and gentamicin (25 mg/L) were added to a simulated blood system (SBS). Four conditions (C1-C4) were tested by defining the filter (Polyflux 170H or F180) and the blood and dialysate flow rates (BFR and DFR). All hemodialysis sessions were 3 hours in length and each condition was completed in duplicate. Dialysate effluent was collected in a 50 gallon polyethylene drum. Samples were collected (in duplicate) from the SBS and the dialysate effluent at baseline and at the end of the hemodialysis session. Samples were analyzed for vancomycin and gentamicin with an ultrahigh performance liquid chromatography/tandem mass spectrometry method.\ud \ud Results\ud A total of eight 3-hour hemodialysis sessions were conducted. For all tested conditions (C1-C4), vancomycin was undetectable in the SBS at the end of dialysis. However, total vancomycin recovery in the dialysis effluent was 85±18%, suggesting that up to 15% may have adsorbed to the dialysis filter or tubing. Gentamicin clearance from SBS was >98% in all tested conditions. Average gentamicin recovery in the dialysate effluent was 99±15%.\ud \ud Conclusion\ud Both vancomycin and gentamicin were readily removed by high-flux hemodialysis under all conditions studied. No significant differences in drug clearance were observed between conditions used in this in vitro study. The clinical implications of changing these hemodialysis parameters are unknown

    Gravitational Wavetrains in the Quasi-Equilibrium Approximation: A Model Problem in Scalar Gravitation

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    A quasi-equilibrium (QE) computational scheme was recently developed in general relativity to calculate the complete gravitational wavetrain emitted during the inspiral phase of compact binaries. The QE method exploits the fact that the the gravitational radiation inspiral timescale is much longer than the orbital period everywhere outside the ISCO. Here we demonstrate the validity and advantages of the QE scheme by solving a model problem in relativistic scalar gravitation theory. By adopting scalar gravitation, we are able to numerically track without approximation the damping of a simple, quasi-periodic radiating system (an oscillating spherical matter shell) to final equilibrium, and then use the exact numerical results to calibrate the QE approximation method. In particular, we calculate the emitted gravitational wavetrain three different ways: by integrating the exact coupled dynamical field and matter equations, by using the scalar-wave monopole approximation formula (corresponding to the quadrupole formula in general relativity), and by adopting the QE scheme. We find that the monopole formula works well for weak field cases, but fails when the fields become even moderately strong. By contrast, the QE scheme remains quite reliable for moderately strong fields, and begins to breakdown only for ultra-strong fields. The QE scheme thus provides a promising technique to construct the complete wavetrain from binary inspiral outside the ISCO, where the gravitational fields are strong, but where the computational resources required to follow the system for more than a few orbits by direct numerical integration of the exact equations are prohibitive.Comment: 15 pages, 14 figure

    A life story in three parts: the use of triptychs to make sense of personal digital data

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    Many social media platforms support the curation of personal digital data, and, more recently, the use of that data for review and reflection. We explored the process of reflection by asking users to create a meaningful ‘triptych’ of photographs drawn from their Facebook accounts. In a first study, we asked participants to manually trawl their own accounts and select three relevant images, which we then framed and used as an interview probe. In a second study, we designed an automated triptych generation system and assessed participants’ experiences of using this system. We conducted qualitative analyses of participant interviews from both studies. Consistent with other ‘slow technology’ work, we found the act of creating a physical artefact from social media data gave that data new meaning, albeit with notable differences between manual vs automatically generated triptychs. We conclude by discussing possible improvements to the design of the automated triptych system

    Quantum Step Heights in Hysteresis Loops of Molecular Magnets

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    We present an analytical theory on the heights of the quantum steps observed in the hysteresis loops of molecular magnets. By considering the dipolar interaction between molecular spins, our theory successfully yields the step heights measured in experiments, and reveals a scaling law for the dependence of the heights on the sweeping rates hidden in the experiment data on Fe8_8 and Mn4_4. With this theory, we show how to accurately determine the tunnel splitting of a single molecular spin from the step heights.Comment: 4 pages, 5 figure

    Planetary Candidates Observed by Kepler V: Planet Sample from Q1-Q12 (36 Months)

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    The Kepler mission discovered 2842 exoplanet candidates with 2 years of data. We provide updates to the Kepler planet candidate sample based upon 3 years (Q1-Q12) of data. Through a series of tests to exclude false-positives, primarily caused by eclipsing binary stars and instrumental systematics, 855 additional planetary candidates have been discovered, bringing the total number known to 3697. We provide revised transit parameters and accompanying posterior distributions based on a Markov Chain Monte Carlo algorithm for the cumulative catalogue of Kepler Objects of Interest. There are now 130 candidates in the cumulative catalogue that receive less than twice the flux the Earth receives and more than 1100 have a radius less than 1.5 Rearth. There are now a dozen candidates meeting both criteria, roughly doubling the number of candidate Earth analogs. A majority of planetary candidates have a high probability of being bonafide planets, however, there are populations of likely false-positives. We discuss and suggest additional cuts that can be easily applied to the catalogue to produce a set of planetary candidates with good fidelity. The full catalogue is publicly available at the NASA Exoplanet Archive.Comment: Accepted for publication, ApJ

    The Kuroshio and Luzon Undercurrent east of Luzon Island

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    Author Posting. © The Oceanography Society, 2015. This article is posted here by permission of The Oceanography Society for personal use, not for redistribution. The definitive version was published in Oceanography 28, no. 4 (2015): 54–63, doi:10.5670/oceanog.2015.81.Current structure, transport, and water mass properties of the northward-flowing Kuroshio and the southward-flowing Luzon Undercurrent (LU) were observed for nearly one year, June 8, 2012–June 4, 2013, across the Kuroshio path at 18.75°N. Observations were made from four platforms: an array of six subsurface ADCP moorings, two Seagliders, fivepressure inverted echo sounders (PIES), and five horizontal electric field (HEF) sensors, providing the most detailed time series of the Kuroshio and Luzon Undercurrent water properties to date. Ocean state estimates of the western boundary current system were performed using the MIT general circulation model—four-dimensional variational assimilation (MITgcm-4D-Var) system. Prominent Kuroshio features from observations are simulated well by the numerical model. Annual mean Kuroshio transport, averaged over all platforms, is ~16 Sv with a standard deviation ~4 Sv. Kuroshio and LU transports and water mass pathways east of Luzon are revealed by Seaglider measurements. In a layer above the salinity maximum associated with North Pacific Tropical Water (NPTW), Kuroshio transport is ~7 Sv and contains North Equatorial Current (NEC) and Western Philippine Sea (WPS) waters, with an insignificant amount of South China Sea water on the shallow western flank. In an intermediate layer containing the core of the NPTW, Kuroshio transport is ~10 Sv, consisting mostly of NEC water. In the lower layer of the Kuroshio, transport is ~1.5 Sv of mostly North Pacific Intermediate Water (NPIW) as a part of WPS waters. Annual mean Luzon Undercurrent southward transport integrated to 1,000 m depth is ~2.7 Sv with a standard deviation ~2 Sv, carrying solely WPS waters below the salinity minimum of the NPIW. The transport of the western boundary current integrated over the full ocean depth east of Luzon Island is ~14 ± 4.5 Sv. Sources of the water masses in the Kuroshio and Luzon Undercurrent are confirmed qualitatively by the numerical model.This work was supported by the US Office of Naval Research (N00014-10-1-0273 and N00014-15-1-2285 to BDC, N00014-10-1-0273 to GG, N00014-14-1-0065 to ALG, N00014-10-1-0468 to TBS, N0001-10-1-0273 to LRC, N00014-10-1-0308 to CML, N00014-10-1-0397 and N00014-10-1-0273 to BM, N00014-10-1-0397 to RCL, and N00014-10-1-0268 to SRJ) and the Taiwan Ministry of Science and Technology. Yang, Chang, and Mensah are supported by the Taiwan Ministry of Science and Technology

    Detailed single crystal EPR lineshape measurements for the single molecule magnets Fe8Br and Mn12-ac

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    It is shown that our multi-high-frequency (40-200 GHz) resonant cavity technique yields distortion-free high field EPR spectra for single crystal samples of the uniaxial and biaxial spin S = 10 single molecule magnets (SMMs) [Mn12O12(CH3COO)16(H2O)4].2CH3COOH.4H2O and [Fe8O2(OH)12(tacn)6]Br8.9H2O. The observed lineshapes exhibit a pronounced dependence on temperature, magnetic field, and the spin quantum numbers (Ms values) associated with the levels involved in the transitions. Measurements at many frequencies allow us to separate various contributions to the EPR linewidths, including significant D-strain, g-strain and broadening due to the random dipolar fields of neighboring molecules. We also identify asymmetry in some of the EPR lineshapes for Fe8, and a previously unobserved fine structure to some of the EPR lines for both the Fe8 and Mn12 systems. These findings prove relevant to the mechanism of quantum tunneling of magnetization in these SMMs.Comment: Phys. Rev. B, accepted with minor revision
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