780 research outputs found

    The effect of ozone exposure on the release of eicosanoids in guinea-pig BAL fluid in relation to cellular damage and inflammation

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    The observed effects after ozone exposure strongly depend on ozone concentration and exposure time. We hypothesized that depending on the O3 exposure protocol, mainly either an oxidant damage or an inflammation will determine the O3 toxicity. We compared two different ozone exposure protocols: an acute exposure (3 ppm 2 h) for studying the oxidant damage and an exposure (1 ppm 12 h) where an inflammatory component is also probably involved. We measured LDH activity and protein and albumin exudation as markers for cellular damage. After the acute exposure an increase in LDH activity was measured and after exposure to 1 ppm ozone for 12 h the exudation of protein and albumin was also enhanced. The histological examinations showed a neutrophilic inflammatory response only after exposure to 1 ppm ozone for 12 h. The acute exposure protocol resulted in an increased release of PGE2, PGD2, PGF2α and 6-ketoPGF1α whereas exposure to 1 ppm ozone for 12 h led to an additional release of LTB4. No effects were measured on the release of TxB2 and LTC4/D4/E4. These changed amounts of eicosanoids will probably contribute to the ozone-induced lung function changes

    In-gas-cell laser ionization spectroscopy in the vicinity of 100Sn: Magnetic moments and mean-square charge radii of N=50-54 Ag

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    In-gas-cell laser ionization spectroscopy studies on the neutron deficient 97-101Ag isotopes have been performed with the LISOL setup. Magnetic dipole moments and mean-square charge radii have been determined for the first time with the exception of 101Ag, which was found in good agreement with previous experimental values. The reported results allow tentatively assigning the spin of 97,99Ag to 9/2 and confirming the presence of an isomeric state in these two isotopes, whose collapsed hyperfine structure suggests a spin of 1/2 . The effect of the N=50 shell closure is not only manifested in the magnetic moments but also in the evolution of the mean-square charge radii of the isotopes investigated, in accordance with the spherical droplet model predictions

    Low-energy Coulomb excitation of 62^{62}Fe and 62^{62}Mn following in-beam decay of 62^{62}Mn

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    Sub-barrier Coulomb-excitation was performed on a mixed beam of 62^{62}Mn and 62^{62}Fe, following in-trap ÎČ−\beta^{-} decay of 62^{62}Mn at REX-ISOLDE, CERN. The trapping and charge breeding times were varied in order to alter the composition of the beam, which was measured by means of an ionisation chamber at the zero-angle position of the Miniball array. A new transition was observed at 418~keV, which has been tentatively associated to a (2+,3+)→1g.s.+(2^{+},3^{+})\rightarrow1^{+}_{g.s.} transition. This fixes the relative positions of the ÎČ\beta-decaying 4+4^{+} and 1+1^{+} states in 62^{62}Mn for the first time. Population of the 21+2^{+}_{1} state was observed in 62^{62}Fe and the cross-section determined by normalisation to the 109^{109}Ag target excitation, confirming the B(E2)B(E2) value measured in recoil-distance lifetime experiments.Comment: 9 pages, 10 figure

    Improved Precision Measurement of the Casimir Force

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    We report an improved precision measurement of the Casimir force. The force is measured between a large Al coated sphere and flat plate using an Atomic Force Microscope. The primary experimental improvements include the use of smoother metal coatings, reduced noise, lower systematic errors and independent measurement of surface separations. Also the complete dielectric spectrum of the metal is used in the theory. The average statistical precision remains at the same 1% of the forces measured at the closest separation

    Coulomb excitation of 68^{68}Ni at safe energies

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    The B(E2;0+→2+)B(E2;0^+\to2^+) value in 68^{68}Ni has been measured using Coulomb excitation at safe energies. The 68^{68}Ni radioactive beam was post-accelerated at the ISOLDE facility (CERN) to 2.9 MeV/u. The emitted γ\gamma rays were detected by the MINIBALL detector array. A kinematic particle reconstruction was performed in order to increase the measured c.m. angular range of the excitation cross section. The obtained value of 2.8−1.0+1.2^{+1.2}_{-1.0} 102^2 e2^2fm4^4 is in good agreement with the value measured at intermediate energy Coulomb excitation, confirming the low 0+→2+0^+\to2^+ transition probability.Comment: 4 pages, 5 figure

    The acquisition of Sign Language: The impact of phonetic complexity on phonology

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    Research into the effect of phonetic complexity on phonological acquisition has a long history in spoken languages. This paper considers the effect of phonetics on phonological development in a signed language. We report on an experiment in which nonword-repetition methodology was adapted so as to examine in a systematic way how phonetic complexity in two phonological parameters of signed languages — handshape and movement — affects the perception and articulation of signs. Ninety-one Deaf children aged 3–11 acquiring British Sign Language (BSL) and 46 hearing nonsigners aged 6–11 repeated a set of 40 nonsense signs. For Deaf children, repetition accuracy improved with age, correlated with wider BSL abilities, and was lowest for signs that were phonetically complex. Repetition accuracy was correlated with fine motor skills for the youngest children. Despite their lower repetition accuracy, the hearing group were similarly affected by phonetic complexity, suggesting that common visual and motoric factors are at play when processing linguistic information in the visuo-gestural modality

    Dietary complexity and hidden costs of prey switching in a generalist top predator

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    Variation in predator diet is a critical aspect of food web stability, health, and population dynamics of predator/ prey communities. Quantifying diet, particularly among cryptic species, is extremely challenging, however, and differentiation between demographic subsets of populations is often overlooked. We used prey remains and data taken postmortem from otter Lutra lutra to determine the extent to which dietary variation in a top predator was associated with biotic, spatial, and temporal factors. Biotic data (e.g., sex, weight, and length) and stomach contents were taken from 610 otters found dead across England and Wales between 1994 and 2010. Prey remains were identified to species where possible, using published keys and reference materials. Multi‐model inference followed by model prediction was applied to test for and visualize the nature of associations. Evidence for widespread decline in the consumption of eels (Anguilla anguilla ) reflected known eel population declines. An association between eel consumption and otter body condition suggested negative consequences for otter nutrition. Consumption of Cottus gobio and stickleback spp. increased, but was unlikely to compensate (there was no association with body condition). More otters with empty stomachs were found over time. Otter sex, body length, and age‐class were important biotic predictors of the prey species found, and season, region, and distance from the coast were important abiotic predictors. Our study is unique in its multivariate nature, broad spatial scale, and long‐term dataset. Inclusion of biotic data allowed us to reveal important differences in costs and benefits of different prey types, and differences between demographic subsets of the population, overlaid on spatial and temporal variation. Such complexities in otter diet are likely to be paralleled in other predators, and detailed characterization of diet should not be overlooked in efforts to conserve wild populations

    Validation of skeletal muscle mass assessment at the level of the third cervical vertebra in patients with head and neck cancer

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    Background: Low skeletal muscle mass (SMM) is associated with adverse outcomes. SMM is often assessed at the third lumbar vertebra (L3) on abdominal imaging. Abdominal imaging is not routinely performed in patients with head and neck cancer (HNC). We aim to validate SMM measurement at the level of the third cervical vertebra (C3) on head and neck imaging. Material and methods: Patients with pre-treatment whole-body computed tomography (CT) between 2010 and 2018 were included. Cross-sectional muscle area (CSMA) was manually delineated at the level of C3 and L3. Correlation coefficients and intraclass correlation coefficients (ICCs) were calculated. Cohen's kappa was used to assess the reliability of identifying a patient with low SMM. Results: Two hundred patients were included. Correlation between CSMA at the level of C3 and L3 was good (r = 0.75, p < 0.01). Using a multivariate formula to estimate CSMA at L3, including gender, age, and weight, correlation improved (r = 0.82, p < 0.01). The agreement between estimated and actual CSMA at L3 was good (ICC 0.78, p < 0.01). There was moderate agreement in the identification of patients with low SMM based on the estimated lumbar skeletal muscle mass index (LSMI) and actual LSMI (Cohen's Îș: 0.57, 95%CI 0.45–0.69). Conclusions: CSMA at C3 correlates well with CSMA at L3. There is moderate agreement in the identification of patients with low SMM based on the estimated lumbar SMI (based on measurement at C3) and actual LSMI

    Complete roughness and conductivity corrections for the recent Casimir force measurement

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    We consider detailed roughness and conductivity corrections to the Casimir force in the recent Casimir force measurement employing an Atomic Force Microscope. The roughness of the test bodies-a metal plate and a sphere- was investigated with the Atomic Force Microscope and the Scanning Electron Microscope respectively. It consists of separate crystals of different heights and a stochastic background. The amplitude of roughness relative to the zero roughness level was determined and the corrections to the Casimir force were calculated up to the fourth order in a small parameter (which is this amplitude divided by the distance between the two test bodies). Also the corrections due to finite conductivity were found up to the fourth order in relative penetration depth of electromagnetic zero point oscillations into the metal. The theoretical result for the configuration of a sphere above a plate taking into account both corrections is in excellent agreement with the measured Casimir force
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