6,914 research outputs found

    Wavelength-independent coupler from fiber to an on-chip cavity, demonstrated over an 850nm span

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    A robust wide band (850 nm) fiber coupler to a whispering-gallery cavity with ultra-high quality factor is experimentally demonstrated. The device trades off ideality for broad-band, efficient input coupling. Output coupling efficiency can remain high enough for practical applications wherein pumping and power extraction must occur over very broad wavelength spans

    ErythropoieSIS stimulating agent (ESA) use is increased following missed dialysis sessions

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    Missed dialysis sessions can have a cascading effect on patient clinical outcomes. In addition to missing the dialysis itself, patients fail to receive medications—such as ESAs—that are dosed at each session. This analysis assessed ESA dose changes following missed session episodes in order to evaluate “catch-up dosing.”In a retrospective analysis, we assessed missed session and epoetin alfa (EPO) utilization data in 2010 from adult (≥ 18 yrs old), hemodialysis (HD) patients. Consecutive misses were considered part of a missed session “episode.” All misses were included (even if patient was hospitalized). Differences in EPO utilization in the periods 14 days, 30 days and 31-60 days before and after missed session episodes were calculated and stratified by length of episode, and whether additional sessions were missed in the before/after periods. Total monthly EPO dose was also calculated and stratified by number of missed sessions.Patients used significantly more EPO after a missed session episode, and differences in per session EPO dose were generally greater the longer the episode. For missed session episodes with no additional misses in the 30 day before/after period, increases of 18% to 30% per session were seen, depending on episode length. For longer episodes, usually due to hospitalization, differences were sustained over 60 days. Analyses which included additional missed sessions in the before/after period showed similar patterns. Beyond these per-session associations, the total amount of EPO used in a month increased with number of missed sessions (through up to 5 missed sessions), even though these patients (by definition) were not receiving as many administrations of EPO.Missed session episodes result in significant increases in ESA utilization in the post-miss period, and also in total monthly ESA use. Such increases should be considered in any assessment of impact of missed sessions: both clinical and economic

    Mgb2 Nonlinear Properties Investigated under Localized High RF Magnetic Field Excitation

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    In order to increase the accelerating gradient of Superconducting Radio Frequency (SRF) cavities, Magnesium Diboride (MgB2) opens up hope because of its high transition temperature and potential for low surface resistance in the high RF field regime. However, due to the presence of the small superconducting gap in the {\pi} band, the nonlinear response of MgB2 is potentially quite large compared to a single gap s-wave superconductor (SC) such as Nb. Understanding the mechanisms of nonlinearity coming from the two-band structure of MgB2, as well as extrinsic sources, is an urgent requirement. A localized and strong RF magnetic field, created by a magnetic write head, is integrated into our nonlinear-Meissner-effect scanning microwave microscope [1]. MgB2 films with thickness 50 nm, fabricated by a hybrid physical-chemical vapor deposition technique on dielectric substrates, are measured at a fixed location and show a strongly temperature-dependent third harmonic response. We propose that at least two mechanisms are responsible for this nonlinear response, one of which involves vortex nucleation and penetration into the film. [1] T. M. Tai, X. X. Xi, C. G. Zhuang, D. I. Mircea, S. M. Anlage, "Nonlinear Near-Field Microwave Microscope for RF Defect Localization in Superconductors", IEEE Trans. Appl. Supercond. 21, 2615 (2011).Comment: 6 pages, 6 figure

    Using the Systematic Review Methodology To Evaluate Factors That Influence the Persistence of Influenza Virus in Environmental Matrices

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    Understanding factors that influence persistence of influenza virus in an environment without host animals is critical to appropriate decision-making for issues such as quarantine downtimes, setback distances, and eradication programs in livestock production systems. This systematic review identifies literature describing persistence of influenza virus in environmental samples, i.e., air, water, soil, feces, and fomites. An electronic search of PubMed, CAB, AGRICOLA, Biosis, and Compendex was performed, and citation relevance was determined according to the aim of the review. Quality assessment of relevant studies was performed using criteria from experts in virology, disease ecology, and environmental science. A total of 9,760 abstracts were evaluated, and 40 appeared to report the persistence of influenza virus in environmental samples. Evaluation of full texts revealed that 19 of the 40 studies were suitable for review, as they described virus concentration measured at multiple sampling times, with viruses detectable at least twice. Seven studies reported persistence in air (six published before 1970), seven in water (five published after 1990), two in feces, and three on surfaces. All three fomite and five air studies addressed human influenza virus, and all water and feces studies pertained to avian influenza virus. Outcome measurements were transformed to half-lives, and resultant multivariate mixed linear regression models identified influenza virus surviving longer in water than in air. Temperature was a significant predictor of persistence over all matrices. Salinity and pH were significant predictors of persistence in water conditions. An assessment of the methodological quality review of the included studies revealed significant gaps in reporting critical aspects of study design

    Understanding orographic effects on surface observations at Macquarie Island

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    The meteorological observations on Macquarie Island have become of increasing value for efforts to understand the unique nature of atmospheric processes over the Southern Ocean. While the island is of modest elevation (peak altitude of 410 m), the orographic effects on observations on this island are still not clear. High-resolution numerical simulations [Weather Research and Forecasting (WRF) Model] with and without terrain have been used to identify orographic effects for four cases representing common synoptic patterns at Macquarie Island: a cold front, a warm front, postfrontal drizzle, and a midlatitude cyclone. Although the simulations cannot capture every possible feature of the precipitation, preliminary results show that clouds and precipitation can readily be perturbed by the island with the main enhancement of precipitation normally in the lee in accordance with the nondimensional mountain height being much less than 1. The weather station is located at the far north end of the island and is only in the lee to southerly and southwesterly winds, which are normally associated with drizzle. The station is on the upwind side for strong northwesterly winds, which are most common and can bring heavier frontal precipitation. Overall the orographic effect on the precipitation record is not found to be significant, except for the enhancement of drizzle found in southwesterly winds. Given the strong winds over the Southern Ocean and the shallow height of the island, the 3D nondimensional mountain height is smaller than 1 in 93.5% of the soundings. As a result, boundary layer flow commonly passes over the island, with the greatest impact in the lee

    Gender Differences in Urothelial Bladder Cancer: Effects of Natural Killer Lymphocyte Immunity

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    Men are more likely to develop cancer than women. In fact, male predominance is one of the most consistent cancer epidemiology findings. Additionally, men have a poorer prognosis and an increased risk of secondary malignancies compared to women. These differences have been investigated in order to better understand cancer and to better treat both men and women. In this review, we discuss factors that may cause this gender difference, focusing on urothelial bladder cancer (UBC) pathogenesis. We consider physiological factors that may cause higher male cancer rates, including differences in X chromosome gene expression. We discuss how androgens may promote bladder cancer development directly by stimulating bladder urothelium and indirectly by suppressing immunity. We are particularly interested in the role of natural killer (NK) cells in anti-cancer immunity

    Square or not Square--That’s the Question!

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    Background: Most heavy metals from industrial catalysts are harmful to human body; however, to function normally, the human body does need traces of essential metal cofactors. Histidine is one of the nine essential amino acids to the human body, and cobalt(II) ion is cost effective and is known to be less toxic to the body. Methods: This project investigates the binding reactions between the cobalt(II) ion and histidine amino acids. Due to unsuccessful attempts to crystalize Cobalt(II)-Histidine complex in the lab, the quantum mechanics modeling package, G09, was employed to provide the binding mode and interaction between the metal and histidine complex. Geometric parameters were attained in order to predict the crystal structure the complex. Results: The data confirms that complexes between cobalt ions and deprotonated histidine will only settle into a square planar geometry, regardless of the initial geometry. However, with neutral histidine, the complex is not in square planar formation at all. Instead, the five-member ring formed among cobalt and histidine’s N- and C-terminus forms an angle, where N-Co-N is almost linear (167.5°). Conclusion: Different reaction conditions will yield either tetrahedral and square planar geometry at the metal center, which will influence the band gap. Such influence can then be used to create a tunable and broadspectrum solar panel materials
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