130,609 research outputs found
Assessing the network connectivity of modifier ions in metaphosphate glass melts: A dynamic light scattering study of Na-Zn mixtures
No full text16164503-164501; 164503-814
Fundementals of Condensed Mater and Crystalline Physics: An Introduction for students of Physics and Materials Science
No full textCan rescuers accurately deliver subtle changes to chest compression depth if recommended by future guidelines?
No full textBackground A recent study reported that a compression depth of 4.56 cm optimised survival following cardiac arrest, which is at variance with the current guidelines of 5.0–6.0 cm. A reduction in recommended compression depth is only likely to improve survival if healthcare professionals can accurately deliver a relatively small change in target depth. This study aimed to determine if healthcare professionals could accurately judge their delivered compression depth by 0.5 cm increments. Method This randomised interventional trial asked BLS-trained healthcare professionals to complete two minutes of continuous chest compressions on an adult manikin, randomised (without any feedback device), to compress to one of three target depth ranges of 4.0–5.0 cm, 4.5–5.5 cm or 5.0–6.0 cm, at the recommended rate of 100–120 compressions min−1. Basic demographic data, compression rate, and compression depth were recorded. Results One hundred and one participants were recruited, of whom one withdrew. Median depths of 3.66 cm (IQR: 3.37–4.16 cm), 4.13 cm (IQR: 3.65–4.36 cm) and 4.76 cm (IQR: 4.16–5.24 cm) were found for the target depths of 4.0–5.0 cm (n = 30), 4.5–5.5 cm (n = 35) and 5.0–6.0 cm (n = 35) respectively (P < 0.001). Overall, 18 participants successfully compressed to their target depth. Conclusions Rescuers are able to judge 0.5 cm differences in compression depth with precision, but remain unable to accurately judge overall target depth. Reducing the current recommended compression depth to 4.56 cm is likely to result in delivered compressions significantly below the optimal depth.</p
Zeitschrift Fur Physikalische Chemie-International Journal of Research in Physical Chemistry & Chemical Physics
No full text11-Oct1161-117022
Physical Review. B, Condensed Matter and Materials Physics
No full textThe viscoelastic relaxation of glass-forming (Na2O)x(P2O5)1−x liquids was measured by photon correlation spectroscopy at temperatures near the glass transition for compositions extending from pure phosphorus pentoxide to the metaphosphate (x=0.5). Over this compositional range, alkali addition produces a continuous depolymerization of the covalently bonded structure from one of a three-dimensional network to that of polymer chains. Substantial increases in the fragility accompany the depolymerization and are shown to be identical to those seen in certain ion-free chalcogenide glass formers suggesting the time scale for viscoelastic relaxation in network-forming liquids is controlled only by the topology of the covalent structure. The relaxation is nonexponential and the stretching exponent shows a complex variation with regards to both composition and temperature that is believed to arise from a decoupling of ionic motions from those of the network occurring as the glass transition is approached.6064201-0642078
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