2,031 research outputs found
Microstructural and physical aspects of heat treated wood, part 1: softwood
Heat treatment of wood is an effective method to improve the dimensional stability and durability against biodegradation. Optimisation of a two-stage heat treatment process at relatively mild conditions (<200°C) and its effect on the anatomical structure of softwoods were investigated by means of a light and scanning electron microscopic analysis. Heat treatment did have an effect on the anatomical structure of wood, although this depends on the wood species considered and on the process method and conditions used. Softwood species with narrow annual rings and/or an abrupt transition from earlywood into latewood were sensitive to tangential cracks in the latewood section. Radial cracks occurred mainly in impermeable wood species such as Norway spruce, caused by large stresses in the wood structure during treatment. Sapwood of treated pine species revealed some damage to parenchyma cells in the rays and epithelial cells around resin canals, whereas this phenomenon has not been noticed in the heartwood section. Treated radiata pine resulted in a very open and permeable wood structure limiting the applications of this species. Broken cell walls perpendicular to the fibre direction resulting in transverse ruptures have been noticed in treated softwood species. This contributes to abrupt fractures of treated wood as observed in bending tests which can lead to considerably different failure behavior after impact or mechanical stress. In some treated softwood species maceration (small cracks between tracheids) was noticed after heat treatment. Heat treatment did not cause damage to the ray parenchyma pit membranes, bordered pits and large window pit membranes; the margo fibrils appeared without damage. Compared to the other softwood timbers tested European grown Douglas fir was the timber that stands heat treatment the best
Îlpha 5 subunit-containing GABAA receptors in temporal lobe epilepsy with normal MRI
GABAA receptors containing the α5 subunit mediate tonic inhibition and are widely expressed in the limbic system. In animals, activation of α5-containing receptors impairs hippocampus-dependent memory. Temporal lobe epilepsy is associated with memory impairments related to neuron loss and other changes. The less selective PET ligand [11C]flumazenil has revealed reductions in GABAA receptors. The hypothesis that α5 subunit receptor alterations are present in temporal lobe epilepsy and could contribute to impaired memory is untested. We compared α5 subunit availability between individuals with temporal lobe epilepsy and normal structural MRI (âMRI-negativeâ) and healthy controls, and interrogated the relationship between α5 subunit availability and episodic memory performance, in a cross-sectional study. Twenty-three healthy male controls (median ± interquartile age 49â±â13âyears) and 11 individuals with MRI-negative temporal lobe epilepsy (seven males; 40â±â8) had a 90-min PET scan after bolus injection of [11C]Ro15-4513, with arterial blood sampling and metabolite correction. All those with epilepsy and six controls completed the Adult Memory and Information Processing Battery on the scanning day. âBandpassâ exponential spectral analyses were used to calculate volumes of distribution separately for the fast component [VF; dominated by signal from α1 (α2, α3)-containing receptors] and the slow component (VS; dominated by signal from α5-containing receptors). We made voxel-by-voxel comparisons between: the epilepsy and control groups; each individual case versus the controls. We obtained parametric maps of VF and VS measures from a single bolus injection of [11C]Ro15-4513. The epilepsy group had higher VS in anterior medial and lateral aspects of the temporal lobes, the anterior cingulate gyri, the presumed area tempestas (piriform cortex) and the insulae, in addition to increases of âŒ24% and âŒ26% in the ipsilateral and contralateral hippocampal areas (Pâ<â0.004). This was associated with reduced VF:VS ratios within the same areas (Pâ<â0.009). Comparisons of VS for each individual with epilepsy versus controls did not consistently lateralize the epileptogenic lobe. Memory scores were significantly lower in the epilepsy group than in controls (mean ± standard deviation â0.4â±â1.0 versus 0.7â±â0.3; Pâ=â0.02). In individuals with epilepsy, hippocampal VS did not correlate with memory performance on the Adult Memory and Information Processing Battery. They had reduced VF in the hippocampal area, which was significant ipsilaterally (Pâ=â0.03), as expected from [11C]flumazenil studies. We found increased tonic inhibitory neurotransmission in our cohort of MRI-negative temporal lobe epilepsy who also had co-morbid memory impairments. Our findings are consistent with a subunit shift from α1/2/3 to α5 in MRI-negative temporal lobe epilepsy
Patients' perspectives on a drug safety monitoring system for immune-mediated inflammatory diseases based on patient-reported outcomes
Patient-reported outcomes (PROs) on adverse drug reactions (ADRs) are increasingly used in cohort event monitoring (CEM) to obtain a better understanding of patientsâ real-world experience with drugs. Despite the leading role for patients, little is known about their perspectives on CEM systems. In a cross-sectional open survey following the rationale of the Technology Acceptance Model, we aimed to obtain insight in patientsâ perspectives on the perceived usefulness, ease of use and attitude toward using a PRO-based drug safety monitoring system for ADRs attributed to biologics. Patients considered structural reporting of ADRs in web-based questionnaires as useful and not burdensome. It was preferred to link the questionnaire frequency to regular hospital consultations or the biologic administration schedule. Various respondents were interested in sharing questionnaires with their medical specialist (49.0%) or pharmacist (34.2%), and suggested to minimize the questionnaire frequency in case of an unaltered situation or absence of ADRs. Patientsâ perspectives should be considered in the setup of PRO-based CEM studies, as this contributes to data quality and patient centeredness. Since incorporation of patientsâ perspectives in CEM studies is indispensable, a delicate balance should be found between user-friendliness and study aims.</p
Detection of Gamma-Ray Emission from the Starburst Galaxies M82 and NGC 253 with the Large Area Telescope on Fermi
We report the detection of high-energy gamma-ray emission from two starburst
galaxies using data obtained with the Large Area Telescope on board the Fermi
Gamma-ray Space Telescope. Steady point-like emission above 200 MeV has been
detected at significance levels of 6.8 sigma and 4.8 sigma respectively, from
sources positionally coincident with locations of the starburst galaxies M82
and NGC 253. The total fluxes of the sources are consistent with gamma-ray
emission originating from the interaction of cosmic rays with local
interstellar gas and radiation fields and constitute evidence for a link
between massive star formation and gamma-ray emission in star-forming galaxies.Comment: Submitted to ApJ Letter
Fermi Gamma-ray Imaging of a Radio Galaxy
The Fermi Gamma-ray Space Telescope has detected the gamma-ray glow emanating
from the giant radio lobes of the radio galaxy Centaurus A. The resolved
gamma-ray image shows the lobes clearly separated from the central active
source. In contrast to all other active galaxies detected so far in high-energy
gamma-rays, the lobe flux constitutes a considerable portion (>1/2) of the
total source emission. The gamma-ray emission from the lobes is interpreted as
inverse Compton scattered relic radiation from the cosmic microwave background
(CMB), with additional contribution at higher energies from the
infrared-to-optical extragalactic background light (EBL). These measurements
provide gamma-ray constraints on the magnetic field and particle energy content
in radio galaxy lobes, and a promising method to probe the cosmic relic photon
fields.Comment: 27 pages, includes Supplementary Online Material; corresponding
authors: C.C. Cheung, Y. Fukazawa, J. Knodlseder, L. Stawar
GPs' attitudes towards digital technologies for depression : an online survey in primary care
BACKGROUND: Digital or electronic mental health (e-mental health) interventions can be useful approaches in reducing the burden of depression, with tools available for use in prevention, treatment, or relapse prevention. They may have specific benefit for primary care, as depression is often managed in this setting. However, little is known about attitudes and barriers among GPs towards e-mental health interventions for depression. AIM: This study aimed to assess attitudes, knowledge, use, and barriers for depression-focused e-mental health among GPs across the UK. DESIGN AND SETTING: An online survey of self-selecting GPs in the UK conducted over a 10-day period in December 2017. METHOD: The survey consisted of 13 multiple choice questions posted on the Doctors.net.uk (DNUK) website. RESULTS: In all, 1044 responses were included; 72% of GPs reported using at least one type of e-mental health intervention for depression. Overall, GPs reported that e-mental health interventions are most effective when delivered in a guided way, rather than in an unguided manner. In addition, 92% of GPs reported that neither they nor their colleagues received e-mental health training. CONCLUSION: A moderate number of GPs use e-mental health for depression in their services, and report it is likely that its use will increase. There is a gap in training and awareness of effective interventions. GPs consider guided e-mental health interventions to be most effective, in contrast to the unguided way it is mostly offered in primary care
Porewater methane transport within the gas vesicles of diurnally migrating Chaoborus spp.: An energetic advantage
We show that diurnally migrating Chaoborus sp. (phantom midge larvae), which can be highly abundant in eutrophic lakes with anoxic bottom, utilises sediment methane to inflate their tracheal sacs, which provides positive buoyancy to aid vertical migration. This process also effectively transports sediment methane bypassing oxidation to the upper water column, adding to the total methane outflux to the atmosphere
Fermi Large Area Telescope observations of PSR J1836+5925
The discovery of the gamma-ray pulsar PSR J1836+5925, powering the formerly
unidentified EGRET source 3EG J1835+5918, was one of the early accomplishments
of the Fermi Large Area Telescope (LAT). Sitting 25 degrees off the Galactic
plane, PSR J1836+5925 is a 173 ms pulsar with a characteristic age of 1.8
million years, a spindown luminosity of 1.1 erg s, and a
large off-peak emission component, making it quite unusual among the known
gamma-ray pulsar population. We present an analysis of one year of LAT data,
including an updated timing solution, detailed spectral results and a long-term
light curve showing no indication of variability. No evidence for a surrounding
pulsar wind nebula is seen and the spectral characteristics of the off-peak
emission indicate it is likely magnetospheric. Analysis of recent XMM
observations of the X-ray counterpart yields a detailed characterization of its
spectrum, which, like Geminga, is consistent with that of a neutron star
showing evidence for both magnetospheric and thermal emission.Comment: Accepted to Astrophysical Journa
Search for Dark Matter Annihilation in the Galactic Center with IceCube-79
The Milky Way is expected to be embedded in a halo of dark matter particles,
with the highest density in the central region, and decreasing density with the
halo-centric radius. Dark matter might be indirectly detectable at Earth
through a flux of stable particles generated in dark matter annihilations and
peaked in the direction of the Galactic Center. We present a search for an
excess flux of muon (anti-) neutrinos from dark matter annihilation in the
Galactic Center using the cubic-kilometer-sized IceCube neutrino detector at
the South Pole. There, the Galactic Center is always seen above the horizon.
Thus, new and dedicated veto techniques against atmospheric muons are required
to make the southern hemisphere accessible for IceCube. We used 319.7 live-days
of data from IceCube operating in its 79-string configuration during 2010 and
2011. No neutrino excess was found and the final result is compatible with the
background. We present upper limits on the self-annihilation cross-section,
\left, for WIMP masses ranging from 30 GeV up to
10 TeV, assuming cuspy (NFW) and flat-cored (Burkert) dark matter halo
profiles, reaching down to cm s, and
cm s for the
channel, respectively.Comment: 14 pages, 9 figures, Submitted to EPJ-C, added references, extended
limit overvie
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