2,801 research outputs found
Wrist-worn Accelerometry for Runners: Objective Quantification of Training Load.
PURPOSE: This study aimed to apply open-source analysis code to raw habitual physical activity data from wrist-worn monitors to: 1) objectively, unobtrusively, and accurately discriminate between "running" and "nonrunning" days; and 2) develop and compare simple accelerometer-derived metrics of external training load with existing self-report measures. METHODS: Seven-day wrist-worn accelerometer (GENEActiv; Activinsights Ltd, Kimbolton, UK) data obtained from 35 experienced runners (age, 41.9 ± 11.4 yr; height, 1.72 ± 0.08 m; mass, 68.5 ± 9.7 kg; body mass index, 23.2 ± 2.2 kg·m; 19 [54%] women) every other week over 9 to 18 wk were date-matched with self-reported training log data. Receiver operating characteristic analyses were applied to accelerometer metrics ("Average Acceleration," "Most Active-30mins," "Mins≥400 mg") to discriminate between "running" and "nonrunning" days and cross-validated (leave one out cross-validation). Variance explained in training log criterion metrics (miles, duration, training load) by accelerometer metrics (Mins≥400 mg, "workload (WL) 400-4000 mg") was examined using linear regression with leave one out cross-validation. RESULTS: Most Active-30mins and Mins≥400 mg had >94% accuracy for correctly classifying "running" and "nonrunning" days, with validation indicating robustness. Variance explained in miles, duration, and training load by Mins≥400 mg (67%-76%) and WL400-4000 mg (55%-69%) was high, with validation indicating robustness. CONCLUSIONS: Wrist-worn accelerometer metrics can be used to objectively, unobtrusively, and accurately identify running training days in runners, reducing the need for training logs or user input in future prospective research or commercial activity tracking. The high percentage of variance explained in existing self-reported measures of training load by simple, accelerometer-derived metrics of external training load supports the future use of accelerometry for prospective, preventative, and prescriptive monitoring purposes in runners
Fabrication of high quality plan-view TEM specimens using the focused ion beam
We describe a technique using a focused ion beam instrument to fabricate high quality plan-view specimens for transmission electron microscopy studies. The technique is simple, site-specific and is capable of fabricating multiple large, >100 μm2 electron transparent windows within epitaxially-grown thin films. A film of La0.67Sr0.33MnO3 is used to demonstrate the technique and its structural and functional properties are surveyed by high resolution imaging, electron spectroscopy, atomic force microscopy and Lorentz electron microscopy. The window is demonstrated to have good thickness uniformity and a low defect density that does not impair the film’s Curie temperature. The technique will enable the study of in–plane structural and functional properties of a variety of epitaxial thin film systems
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A prospective, randomised, double-blind, double-dummy, placebo-controlled trial to assess the respiratory effects of buprenorphine versus morphine in anaesthetised patients
Despite its long history and widespread use, some questions remain over buprenorphine’s respiratory safety profile. This study investigated respiratory depression and potential reversibility by naloxone at two buprenorphine doses, of which the intramuscularly administered dose was designed to achieve the plasma concentration range seen with transdermal delivery. The buprenorphine doses were compared to morphine administered intravenously.
The IM route was proposed to avoid the characteristic high peak seen after IV bolus injection, to achieve a slow-rising plasma concentration which plateaus at five minutes, The selected intramuscular buprenorphine dose (0.85 mcg/kg) was chosen to achieve a similar plasma concentration at a steady state to that seen with transdermal buprenorphine at 35mcg/h(the Transtec 35mcg/h patch)
A Xenon Condenser with a Remote Liquid Storage Vessel
We describe the design and operation of a system for xenon liquefaction in
which the condenser is separated from the liquid storage vessel. The condenser
is cooled by a pulse tube cryocooler, while the vessel is cooled only by the
liquid xenon itself. This arrangement facilitates liquid particle detector
research by allowing easy access to the upper and lower flanges of the vessel.
We find that an external xenon gas pump is useful for increasing the rate at
which cooling power is delivered to the vessel, and we present measurements of
the power and efficiency of the apparatus.Comment: 22 pages, 7 figures Corrected typos in authors lis
Advanced chronic liver disease in the last year of life: a mixed methods study to understand how care in a specialist liver unit could be improved
Objective: To identify the limitations in palliative care provision in the last year of life for people with liver cirrhosis and potential barriers to and enablers of palliative care. / Design: Mixed methods, including a retrospective case note review, qualitative focus groups and individual interviews. / Setting: A tertiary referral liver centre in the south of England (UK). / Participants: Purposively selected case notes of 30 people with cirrhosis who attended the tertiary referral liver centre and died during an 18-month period; a purposive sample of 22 liver health professionals who participated in either focus groups or individual interviews. / Primary and secondary outcomes: Data collected from case notes included hospital admissions, documented discussions of prognosis and palliative care provision. Qualitative methods explored management of people with cirrhosis, and barriers to and enablers of palliative care. / Results: Participants had high rates of hospital admissions and symptom burden. Clinicians rarely discussed prognosis or future care preferences; they lacked the skills and confidence to initiate discussions. Palliative care provision occurred late because clinicians were reluctant to refer due to their perception that reduced liver function is reversible, poor understanding of the potential of a palliative approach; palliative care was perceived negatively by patients and families. / Conclusions: People dying with cirrhosis have unpredictable trajectories, but share a common pathway of frequent admissions and worsening symptoms as death approaches. The use of clinical tools to identify the point of irreversible deterioration and joint working between liver services and palliative care may improve care for people with cirrhosis
Complete conversion between one and two photons in nonlinear waveguides: Theory of dispersion engineering
High-efficiency photon-pair production is a long-sought-after goal for many optical quantum technologies, and coherent photon conversion (CPC) processes are promising candidates for achieving this. We show theoretically how to control coherent conversion between a narrow-band pump photon and broadband photon pairs in nonlinear optical waveguides by tailoring frequency dispersion for broadband quantum frequency mixing. We reveal that complete deterministic conversion as well as pump-photon revival can be achieved at a finite propagation distance. We also find that high conversion efficiencies can be realised robustly over long propagation distances. These results demonstrate that dispersion engineering is a promising way to tune and optimise the CPC process. © 2022 The Author(s). Published by IOP Publishing Ltd on behalf of the Institute of Physics and Deutsche Physikalische Gesellschaft.Australian Research Council, ARC: DE180100070, DP160100619, DP190100277, FT170100399; Ministry of Education and Science of the Russian Federation, Minobrnauka: AAAA-A18-118020190095-4The authors acknowledge the support by the Australian Research Council (DE180100070, DP160100619, DP190100277). NKL is funded by the Australian Research Council Future Fellowship (FT170100399). Batalov S V acknowledges support by the Ministry of Education and Science of the Russian Federation (the theme ‘Quantum’, No. AAAA-A18-118020190095-4)
Optimal quantum cloning of orbital angular momentum photon qubits via Hong-Ou-Mandel coalescence
The orbital angular momentum (OAM) of light, associated with a helical
structure of the wavefunction, has a great potential for quantum photonics, as
it allows attaching a higher dimensional quantum space to each photon.
Hitherto, however, the use of OAM has been hindered by its difficult
manipulation. Here, exploiting the recently demonstrated spin-OAM information
transfer tools, we report the first observation of the Hong-Ou-Mandel
coalescence of two incoming photons having nonzero OAM into the same outgoing
mode of a beam-splitter. The coalescence can be switched on and off by varying
the input OAM state of the photons. Such effect has been then exploited to
carry out the 1 \rightarrow 2 universal optimal quantum cloning of OAM-encoded
qubits, using the symmetrization technique already developed for polarization.
These results are finally shown to be scalable to quantum spaces of arbitrary
dimension, even combining different degrees of freedom of the photons.Comment: 5 pages, 3 figure
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Investigation of oesophageal photoplethysmographic signals and blood oxygen saturation measurements in cardiothoracic surgery patients
Pulse oximeter probes attached to the finger may fail to estimate blood oxygen saturation (SpO2) in patients with compromised peripheral perfusion (e.g. hypothermic cardiopulmonary bypass surgery). The measurement of SpO2 from a central organ such as the oesophagus is suggested as an alternative to overcome this problem. A reflectance oesophageal pulse oximeter probe and a processing system implemented in LabVIEW were developed. The system was evaluated in clinical measurements on 50 cardiothoracic surgery patients. Oesophageal photoplethysmographic (PPG) signals with large amplitudes and high signal-to-noise ratios were measured from various depths within the oesophagus from all the cardiothoracic patients. The oesophageal PPG amplitudes from these patients were in good agreement with previous oesophageal PPG amplitude measurements from healthy anaesthetized patients. The oesophageal pulse oximeter SpO2 results agreed well with the estimated arterial oxygen saturation (SaO2) values inferred from the oxygen tension obtained by blood gas analysis. The mean (+/- SD) of the differences between the oesophageal pulse oximeter SpO2 readings and those from blood gas analysis was 0.02 +/- 0.88%. Also, the oesophageal pulse oximeter was found to be reliable and accurate in five cases of poor peripheral perfusion when a commercial finger pulse oximeter probe failed to estimate oxygen saturation values for at least 10 min. These results suggest that the arterial blood circulation to the oesophagus is less subject to vasoconstriction and decreased PPG amplitudes than are the peripheral sites used for pulse oximetry such as the finger. It is concluded that oesophageal SPO2 monitoring may be of clinical value
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