4,593 research outputs found
Neutrino Oscillometry
Neutrino oscillations are studied employing sources of low energy
monoenergetic neutrinos following electron capture by the nucleus and measuring
electron recoils. Since the neutrino energy is very low the oscillation length
appearing in this electronic neutrino disappearance experiment can be so small
that the full oscillation can take place inside the detector. Thus one may
determine very accurately all the neutrino oscillation parameters. In
particular one can measure or set a better limit on the unknown parameter
theta13. One, however, has to pay the price that the expected counting rates
are very small. Thus one needs a very intensive neutrino source and a large
detector with as low as possible energy threshold and high energy and position
resolution. Both spherical gaseous and cylindrical liquid detectors are
studied. Different source candidates are consideredComment: 6 pages, 1 table 3 figures. Presented in the conferences PASCOS10,
Valencia spain and Neutrino 2010, Athens Greec
Impulse oscillometry identifies peripheral airway dysfunction in children with adenosine deaminase deficiency.
Adenosine deaminase-deficient severe combined immunodeficiency (ADA-SCID) is characterized by impaired T-, B- and NK-cell function. Affected children, in addition to early onset of infections, manifest non-immunologic symptoms including pulmonary dysfunction likely attributable to elevated systemic adenosine levels. Lung disease assessment has primarily employed repetitive radiography and effort-dependent functional studies. Through impulse oscillometry (IOS), which is effort-independent, we prospectively obtained objective measures of lung dysfunction in 10 children with ADA-SCID. These results support the use of IOS in the identification and monitoring of lung function abnormalities in children with primary immunodeficiencies
Novel Device for Measuring Lung Function using Oscillometry
The forced oscillation technique (FOT) is a non-invasive means of measuring lung mechanics. Broad-band oscillations in flow are delivered to the lungs while the resultant pressure oscillations are recorded. These signals are processed to yield the input impedance of the respiratory system (Zrs), which encapsulates the mechanical properties of the lung over the frequency range spanned by the oscillations. Clinically, can be used to assess pulmonary pathologies such as asthma and COPD. Standard methods of performing FOT are limited to the non-ambulatory clinical setting. Production of a light-weight device that operates without an external power source would allow real-time measurements of in a wide variety of more natural settings. Breath-driven oscillators, such as the Smith’s Medical Acapella and D R Burton vPEP, are currently used clinically to help cystic fibrosis patients clear mucus from their lungs by generating pressure oscillations that travel into the airways. We hypothesized that these oscillations could be used to determine . We performed FOT on healthy individuals without history of lung disease using a calibrated piston oscillator (Flexivent) to determine reference between 1 and 20 Hz. We then measured airway pressure and flow using the same sensors but with the oscillations produced by the Acapella and vPEP during tidal breathing. Respiratory resistance (Rrs), elastance (Ers) and Inertance (Irs) were determined by fitting the single-compartment model of the respiratory system to the time-domain signals from all three measurement devices. Correlation coefficients, Bland-Altman plots, and coefficients of variation were used to compare the results obtained with the three devices. We found bias values of 0.633857 [0.214382378, 1.053331908] cmH2O.s.L-1, 0.041333 [-0.38432604, 0.46699271] cmH2O.s.L-1 for comparing the Flexivent against the Acapella and vPEP, respectively. Coefficients of variation of 9.003%, 9.855%, and 9.643% were obtained for the Flexivent, Acapella, and vPEP, respectively. These results demonstrate that breath-driven oscillators are promising alternatives to conventional powered oscillators for the measurement of
Reference values of impulse oscillometric lung function indices in adults of advanced age.
Impulse oscillometry (IOS) is a non-demanding lung function test. Its diagnostic use may be particularly useful in patients of advanced age with physical or mental limitations unable to perform spirometry. Only few reference equations are available for Caucasians, none of them covering the old age. Here, we provide reference equations up to advanced age and compare them with currently available equations.
IOS was performed in a population-based sample of 1990 subjects, aged 45-91 years, from KORA cohorts (Augsburg, Germany). From those, 397 never-smoking, lung healthy subjects with normal spirometry were identified and sex-specific quantile regression models with age, height and body weight as predictors for respiratory system impedance, resistance, reactance, and other parameters of IOS applied.
Women (n = 243) showed higher resistance values than men (n = 154), while reactance at low frequencies (up to 20 Hz) was lower (p<0.05). A significant age dependency was observed for the difference between resistance values at 5 Hz and 20 Hz (R5-R20), the integrated area of low-frequency reactance (AX), and resonant frequency (Fres) in both sexes whereas reactance at 5 Hz (X5) was age dependent only in females. In the healthy subjects (n = 397), mean differences between observed values and predictions for resistance (5 Hz and 20 Hz) and reactance (5 Hz) ranged between -1% and 5% when using the present model. In contrast, differences based on the currently applied equations (Vogel & Smidt 1994) ranged between -34% and 76%. Regarding our equations the indices were beyond the limits of normal in 8.1% to 18.6% of the entire KORA cohort (n = 1990), and in 0.7% to 9.4% with the currently applied equations.
Our study provides up-to-date reference equations for IOS in Caucasians aged 45 to 85 years. We suggest the use of the present equations particularly in advanced age in order to detect airway dysfunction
Probing the fourth neutrino existence by neutral current oscillometry in the spherical gaseous TPC
It is shown that, if the "new neutrino" implied by the Reactor Neutrino
Anomaly exists and is in fact characterized by the suggested relatively high
mass squared difference and reasonably large mixing angle, it should clearly
reveal itself in the oscillometry measurements. For a judicious neutrino source
the "new oscillation length L14 is expected shorter than 3m. Thus the needed
measurements can be implemented with a gaseous spherical TPC of modest
dimensions with a very good energy and position resolution, detecting nuclear
recoils following the coherent neutrino-nucleus elastic scattering. The best
candidates for oscillometry, yielding both monochromatic neutrinos as well as
antineutrinos, are discussed. A sensitivity in the mixing angle theta14,
(sin(2\theta14))^2=0.1 (99 %), can be reached after a few months of data
handling.Comment: 18 LaTex pages, 11 figures, 2 table
Prenatal Vitamin D Supplementation and Child Respiratory Health: A Randomised Controlled Trial
PMCID: PMC3691177This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
CHLOROBENZENE AS A DIFFERENTIATING SOLVENT FOR THE OSCILLOMETRIC TITRATION OF WEAK ORGANIC BASES
What can we learn about COPD from impulse oscillometry?
Impulse oscillometry (IOS) is the most commonly used type of forced oscillation technique in clinical practice, although relatively little is known about its application in COPD. Resistance at 20 Hz (R20) is unrelated to COPD severity and does not improve with bronchodilatation or bronchoconstriction, inferring a lack of large airway involvement in COPD. Peripheral airway resistance expressed as frequency dependent heterogeneity between 5 Hz and 20 Hz (R5-R20), and peripheral airway compliance as area under the reactance curve (AX), are both closely related to COPD severity and exacerbations. Both R5-R20 and AX markedly improve in response to long acting bronchodilators, while AX appears to be more sensitive than R5-R20 in response to bronchoconstriction. Future studies may be directed to assess if IOS in combination with spirometry is more sensitive at predicting future exacerbations. Perhaps AX might also be useful as a screening tool in early stage disease or to monitor long term decline in COPD.</p
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