4,314 research outputs found
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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 buprenorphineâs 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)
Constraining anomalous Higgs boson couplings to virtual photons
We present a study of Higgs boson production in vector boson fusion and in
association with a vector boson and its decay to two vector bosons, with a
focus on the treatment of virtual loops and virtual photons. Our analysis is
performed with the JHU generator framework. Comparisons are made to several
other frameworks, and the results are expressed in terms of an effective field
theory. New features of this study include a proposal on how to handle
singularities involving Higgs boson decays to light fermions via photons,
calculation of the partial Higgs boson width in the presence of anomalous
couplings to photons, a comparison of the next-to-leading-order electroweak
corrections to effects from effective couplings, and phenomenological
observations regarding the special role of intermediate photons in analysis of
LHC data in the effective field theory framework. Some of these features are
illustrated with projections for experimental measurements with the full LHC
and HL-LHC datasets.Comment: 32 pages, 14 figure
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Beer-Lambert law along non-linear mean light pathways for the rational analysis of Photoplethysmography
Photoplethysmography (PPG) is a technique that uses light to noninvasively obtain a volumetric measurement of an organ with each cardiac cycle. A PPG-based system emits monochromatic light through the skin and measures the fraction of the light power which is transmitted through a vascular tissue and detected by a photodetector. Part of thereby transmitted light power is modulated by the vascular tissue volume changes due to the blood circulation induced by the heart beating. This modulated light power plotted against time is called the PPG signal. Pulse Oximetry is an empirical technique which allows the arterial blood oxygen saturation (SpO2 â molar fraction) evaluation from the PPG signals. There have been many reports in the literature suggesting that other arterial blood chemical components molar fractions and concentrations can be evaluated from the PPG signals. Most attempts to perform such evaluation on empirical bases have failed, especially for components concentrations. This paper introduces a non-empirical physical model which can be used to analytically investigate the phenomena of PPG signal. Such investigation would result in simplified engineering models, which can be used to design validating experiments and new types of spectroscopic devices with the potential to assess venous and arterial blood chemical composition in both molar fractions and concentrations non-invasively
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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
The development and evaluation of the Writing Assessment Measure (WAM) to assess children's narrative writing.
The study evaluated the reliability and validity of the Writing Assessment Measure (WAM), developed to reflect the skills which children of different abilities are expected to achieve in written expression, as part of the National Curriculum guidelines in England and Wales. The focus was on its potential use in investigations of children's written narrative in order to inform and target related interventions. The study involved 97 children aged 7â11 from one urban primary school in England. Prompt 1 was administered to all the children in their classrooms together with a standardised written expression test. After three weeks, the same procedure was followed and Prompt 2 was administered. Statistical analyses of the reliability and validity of the instrument showed that it is consistent over time and can be scored reliably by different raters. Content validity of the instrument was demonstrated through inspection of item total correlations which were all significant. Analyses for concurrent validity showed that the instrument correlates significantly with the Wechsler Written Expressive Language sub-test. Significant differences between children of different age and writing skill were also found. The findings indicate that the instrument has potential utility to professionals assessing children's writing
'I would rather die': reasons given by 16-year-olds for not continuing their study of mathematics
Improving participation rates in specialist mathematics after the subject ceases to be compulsory at age 16 is part of government policy in England. This article provides independent and recent support for earlier findings concerning reasons for non- participation, based on free response and closed items in a questionnaire with a sample of over 1500 students in 17 schools, close to the moment of choice. The analysis supports findings that perceived difficulty and lack of confidence are important reasons for students not continuing with mathematics, and that perceived dislike and boredom, and lack of relevance, are also factors. There is a close relationship between reasons for non-participation and predicted grade, and a weaker relation to gender. An analysis of the effects of schools, demonstrates that enjoyment is the main factor differentiating schools with high and low participation indices. Building on discussion of these findings, ways of improving participation are briefly suggested
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Investigation of finger reflectance photoplethysmography in volunteers undergoing a local sympathetic stimulation
Optical sensors used in clinical applications have gained great popularity over the last few decades, especially the photoplethysmographic (PPG) technique used in estimating arterial blood oxygen saturation in the well-known medical devices called pulse oximeters. In this study we investigate the photoplethysmogram further in an effort to understand its origin better, as there is a significant void in the current knowledge on the PPG quantitative measurement. The photoplethysmographic signal provides a heart rhythm pulsating AC component, and a non-pulsating DC component. The signal is commonly believed to originate from tissue volume changes only and hasn't been investigated intensively. This in vivo study examines the source of the PPG signal in relation to pulse amplitude and pulse rhythm while volunteers undergo a right hand ice immersion. It was found that the PPG signal is sensitive in detecting the sympathetic stimulation which corresponds to volumetric and heart rate changes. During the immersion, AC pulse amplitudes (PA) from both hands decreased significantly, while DC levels increased significantly in the right hand and non-significantly in the left hand. Also, a significant decrease in the pulse repetition time (PRT) was observed. Using blood pressure-flow theories, these results suggest that there are possibly other factors in the blood flow regulation that alter the blood optical density which contributes to the detected signal. Further studies need to investigate PPGs in relation to blood optical density and the dynamics of the pulsatile flow effects besides volumetric changes. Such investigations might explore further applications of the PPG in medicine
Optimization Based Partitioning Selection for Improved Contaminant Detection Performance
Indoor Air Quality monitoring is an essential
ingredient of intelligent buildings. The release of various airborne contaminants into the buildings, compromises the health and safety of occupants. Therefore, early contaminant detection is of paramount importance for the timely activation of proper contingency plans in order to minimize the impact of
contaminants on occupants health. The objective of this work is to enhance the performance of a distributed contaminant detection methodology, in terms of the minimum detectable contaminant release rates, by considering the joint problem of partitioning selection and observer gain design. Towards this direction, a detectability analysis is performed to derive
appropriate conditions for the minimum guaranteed detectable contaminant release rate for specific partitioning configuration and observer gains. The derived detectability conditions are then exploited to formulate and solve an optimization problem for jointly selecting the partitioning configuration and observer
gains that yield the best contaminant detection performance
Snowmass White Paper: Prospects of CP-violation measurements with the Higgs boson at future experiments
The search for CP violation in interactions of the Higgs boson with either
fermions or bosons provides attractive reference measurements in the Particle
Physics Community Planning Exercise (a.k.a. "Snowmass"). Benchmark measurements
of CP violation provide a limited and well-defined set of parameters that could
be tested at the proton, electron-positron, photon, and muon colliders, and
compared to those achieved through study of virtual effects in electric dipole
moment measurements. We review the current status of these CP-sensitive studies
and provide projections to future measurements.Comment: Snowmass White Paper. 23 pages, 6 figure
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