8,094 research outputs found

    The Mortality Response to Absolute and Relative Temperature Extremes

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    While the impact of absolute extreme temperatures on human health has been amply studied, far less attention has been given to relative temperature extremes, that is, events that are highly unusual for the time of year but not necessarily extreme relative to a location\u27s overall climate. In this research, we use a recently defined extreme temperature event metric to define absolute extreme heat events (EHE) and extreme cold events (ECE) using absolute thresholds, and relative extreme heat events (REHE) and relative extreme cold events (RECE) using relative thresholds. All-cause mortality outcomes using a distributed lag nonlinear model are evaluated for the largest 51 metropolitan areas in the US for the period 1975-2010. Both the immediate impacts and the cumulative 20-day impacts are assessed for each of the extreme temperature event types. The 51 metropolitan areas were then grouped into 8 regions for meta-analysis. For heat events, the greatest mortality increases occur with a 0-day lag, with the subsequent days showing below-expected mortality (harvesting) that decreases the overall cumulative impact. For EHE, increases in mortality are still statistically significant when examined over 20 days. For REHE, it appears as though the day-0 increase in mortality is short-term displacement. For cold events, both relative and absolute, there is little mortality increase on day 0, but the impacts increase on subsequent days. Cumulative impacts are statistically significant at more than half of the stations for both ECE and RECE. The response to absolute ECE is strongest, but is also significant when using RECE across several southern locations, suggesting that there may be a lack of acclimatization, increasing mortality in relative cold events both early and late in winter

    Adapting tissue-engineered in vitro CNS models for high-throughput study of neurodegeneration

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    Neurodegenerative conditions remain difficult to treat, with the continuing failure to see therapeutic research successfully advance to clinical trials. One of the obstacles that must be overcome is to develop enhanced models of disease. Tissue engineering techniques enable us to create organised artificial central nervous system tissue that has the potential to improve the drug development process. This study presents a replicable model of neurodegenerative pathology through the use of engineered neural tissue co-cultures that can incorporate cells from various sources and allow degeneration and protection of neurons to be observed easily and measured, following exposure to neurotoxic compounds - okadaic acid and 1-methyl-4-phenylpyridinium. Furthermore, the technology has been miniaturised through development of a mould with 6 mm length that recreates the advantageous features of engineered neural tissue co-cultures at a scale suitable for commercial research and development. Integration of human-derived induced pluripotent stem cells aids more accurate modelling of human diseases, creating new possibilities for engineered neural tissue co-cultures and their use in drug screening

    Atomic alignment and Diagnostics of Magnetic Fields in Diffuse Media

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    We continue our studies of atomic alignment in diffuse media, in particularly, in interstellar and circumstellar media, with the goal of developing new diagnostics of magnetic fields in these environments. We understand atomic alignment as alignment of atoms or ions in their ground state. Such atoms are sensitive to weak magnetic fields. In particular, we provide predictions of the polarization that arises from astrophysically important aligned atoms (ions) with fine structure of the ground level, namely, OI and SII and Ti II. Unlike our earlier papers which dealt with weak fields only, a substantial part of our current paper is devoted to the studies of atomic alignment when magnetic fields get strong enough to affect the emission from the excited level, i.e. with the regime when the magnetic splitting is comparable to the line-width. This is a regime of Hanle effect modified by the atomic alignment. Using an example of emission and absorption lines of SII ion we demonstrate how polarimetric studies can probe magnetic fields in circumstellar regions and accretion disks. In addition, we show that atomic alignment induced by anisotropic radiation can induce substantial variations of magnetic dipole transitions within the ground state, thus affecting abundance studies based on this emission. Moreover, the radio emission is polarized, provides a new way to study magnetic fields, e.g. at the epoch of Universe reionization.Comment: Minor changes, accepted to Ap

    Weekly doxorubicin and continuous infusional 5-fluorouracil for advanced breast cancer.

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    Drug scheduling alterations can improve the therapeutic index of both 5-fluorouracil and anthracyclines. We investigated a regimen of weekly doxorubicin and continuous infusional 5-fluorouracil (AcF) in loco-regionally recurrent and metastatic breast cancer. The aims of this phase II study were to use low-dose weekly anthracyclines in a patient group where liver metastases are a frequent problem, to optimise scheduling of 5-fluorouracil using continuous infusion and to conserve alkylating agent use for late intensification in responding patients. Fifty-six patients received 5-fluorouracil 200 mg m-2 day-1 and doxorubicin 20-30 mg m-2 week-1 for at least 6 weeks. Sixty-two percent were chemonaive. Patients were evaluated for dose intensity, response, toxicity and survival. Of the assessable patients, 76% achieved UICC response criteria (20% complete response, 56% partial response). WHO grade 3+ toxicities were: alopecia, 98%; mucositis, 62%; neutropenia, 22%; and grade 3 palmar-plantar syndrome, 24%. Median survival was 13 months, with visceral metastasis conferring a significantly worse outcome (P = 0.03). Grade 3+ mucositis was more frequent with planned doxorubicin dose intensity > or = 25 mg m-2 week-1 (P = 0.04). AcF is highly active in breast cancer with acceptable toxicities and can be used before alkylating agent-based high-dose therapy

    The pairing state in KFe2As2 studied by measurements of the magnetic vortex lattice

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    Understanding the mechanism and symmetry of electron pairing in iron-based superconductors represents an important challenge in condensed matter physics [1-3]. The observation of magnetic flux lines - "vortices" - in a superconductor can contribute to this issue, because the spatial variation of magnetic field reflects the pairing. Unlike many other iron pnictides, our KFe2As2 crystals have very weak vortex pinning, allowing small-angle-neutron-scattering (SANS) observations of the intrinsic vortex lattice (VL). We observe nearly isotropic hexagonal packing of vortices, without VL-symmetry transitions up to high fields along the fourfold c-axis of the crystals, indicating rather small anisotropy of the superconducting properties around this axis. This rules out gap nodes parallel to the c-axis, and thus d-wave and also anisotropic s-wave pairing [2, 3]. The strong temperature-dependence of the intensity down to T<<Tc indicates either widely different full gaps on different Fermi surface sheets, or nodal lines perpendicular to the axis.Comment: 13 pages, 3 figure

    The influence of poly (2-methoxyaniline-5-sulfonic acid) on the electrochemical and photochemical properties of a highly luminescent ruthenium complex

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    Immobilisation of a luminescent material on an electrode surface is well known to substantially modulate its photophysical and electrochemical properties. Here a positively charged ruthenium metal complex ([Ru(bpy)(3)](2+)) is immobilised on all electrode surface by ion paring with a sulfonated conducting polymer poly(2-methoxyaniline-5-sulfonic acid), (PMAS). Significantly, our study reveals that the electron transport between the ruthenium metal centres can be greatly enhanced due to the interaction with the conducting polymer when both are surface confined. Charge transfer diffusion rates in the present system are an order of magnitude faster than those found where the metal centre is immobilised within a non-conducting polymeric matrix. Electron transport appears to be mediated through the PMAS conjugated structure, contrasting with the electron hopping process typically observed in non-conducting metallopolymers. This increased regeneration rate causes the ruthenium-based electrochemiluminescence (ECL) efficiency to be increased. The impact of these observations on the ECL detection of low concentrations of disease biomarkers is discussed. (c) 2007 Published by Elsevier Ltd

    Detection of Vacuum Birefringence with Intense Laser Pulses

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    We propose a novel technique that promises hope of being the first to directly detect a polarization in the quantum electrodynamic (QED) vacuum. The technique is based upon the use of ultra-short pulses of light circulating in low dispersion optical resonators. We show that the technique circumvents the need for large scale liquid helium cooled magnets, and more importantly avoids the experimental pitfalls that plague existing experiments that make use of these magnets. Likely improvements in the performance of optics and lasers would result in the ability to observe vacuum polarization in an experiment of only a few hours duration.Comment: 4 pages, 1 figur

    Historical geography II: traces remain

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    The second report in this series turns to focus on the trace in relation to life-writing and biography in historical geography and beyond. Through attention to tracing journeys, located moments and listening to the presence of ghosts (Ogborn, 2005), this report seeks to highlight the range of different ways in which historical geographers have explored lives, deaths, and their transient traces through varied biographical terrains. Continuing to draw attention in historical geography to the darkest of histories, this piece will pivot on moments of discovering the dead to showcase the nuanced ways in which historical geography is opening doors into uncharted lives and unspoken histories

    Vortex lattice structure in BaFe2(As0.67P0.33)2 by the small-angle neutron scattering technique

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    We have observed a magnetic vortex lattice (VL) in BaFe2(As_{0.67}P_{0.33})2 (BFAP) single crystals by small-angle neutron scattering (SANS). With the field along the c-axis, a nearly isotropic hexagonal VL was formed in the field range from 1 to 16 T, which is a record for this technique in the pnictides, and no symmetry changes in the VL were observed. The temperature-dependence of the VL signal was measured and confirms the presence of (non d-wave) nodes in the superconducting gap structure for measurements at 5 T and below. The nodal effects were suppressed at high fields. At low fields, a VL reorientation transition was observed between 1 T and 3 T, with the VL orientation changing by 45{\deg}. Below 1 T, the VL structure was strongly affected by pinning and the diffraction pattern had a fourfold symmetry. We suggest that this (and possibly also the VL reorientation) is due to pinning to defects aligned with the crystal structure, rather than being intrinsic.Comment: 9 pages, 9 figure
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