The Experts below are selected from a list of 318 Experts worldwide ranked by ideXlab platform
Wolfram Miekisch - One of the best experts on this subject based on the ideXlab platform.
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continuous real time breath analysis in ruminants effect of eructation on exhaled voc profiles
Journal of Breath Research, 2018Co-Authors: Pete Oertel, Anne Kuntzel, Petra Reinhold, Heike Kohle, Joche K Schube, Joha Kolb, Wolfram MiekischAbstract:Background. The analysis of volatile organic compounds (VOCs) in breath allows non-invasive investigations of diseases. Animal studies are conducted as a model to perform research of VOCs and their relation to diseases. In large animal models ruminants were often used as experimental targets. The effect of their physiological eructation on VOC Exhalation has not been examined yet and is the objective of this study. Methods. Continuous breath profiles of two young cattle, four adult goats and four adult sheep were measured through a mask, covering mouth and nose, in real-time (200 ms) by means of proton transfer reaction time of flight mass spectrometry. Each animal was analysed twelve times for 3 consecutive minutes. Results. Real-time monitoring yielded a distinction of different episodes in the breath profiles of ruminants. An algorithm to separate eructation episodes and alveolar breath was established. In the first Exhalation after eructation at least 19 VOC concentrations increased (up to 36-fold) and went back to initial levels in subsequent Exhalations in all investigated ruminants. Decay of concentrations was substance specific. In goats, less VOCs were affected by the eructation compared to cattle and sheep. Breath profiles without exclusion of eructation episodes showed higher variations and median values than profiles where eructation episodes were excluded. Conclusion. Real-time breath analysis of ruminants enables the discrimination and characterisation of alveolar breath and eructation episodes. This leads to a better understanding of variation in breath data and possible origins of VOCs: breath or digestion related. To avoid impairment of breath gas results and to gain further information on bacterial products from the rumen, eructation and alveolar breath data should be analysed separately.
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FEV manoeuvre induced changes in breath VOC compositions: an unconventional view on lung function tests
Scientific Reports, 2016Co-Authors: Pritam Sukul, Jochen K. Schubert, Peter Oertel, Svend Kamysek, Khushman Taunk, Phillip Trefz, Wolfram MiekischAbstract:Breath volatile organic compound (VOC) analysis can open a non-invasive window onto pathological and metabolic processes in the body. Decades of clinical breath-gas analysis have revealed that changes in exhaled VOC concentrations are important rather than disease specific biomarkers. As physiological parameters, such as respiratory rate or cardiac output, have profound effects on exhaled VOCs, here we investigated VOC Exhalation under respiratory manoeuvres. Breath VOCs were monitored by means of real-time mass-spectrometry during conventional FEV manoeuvres in 50 healthy humans. Simultaneously, we measured respiratory and hemodynamic parameters noninvasively. Tidal volume and minute ventilation increased by 292 and 171% during the manoeuvre. FEV manoeuvre induced substance specific changes in VOC concentrations. pET-CO_2 and alveolar isoprene increased by 6 and 21% during maximum Exhalation. Then they decreased by 18 and 37% at forced expiration mirroring cardiac output. Acetone concentrations rose by 4.5% despite increasing minute ventilation. Blood-borne furan and dimethyl-sulphide mimicked isoprene profile. Exogenous acetonitrile, sulphides, and most aliphatic and aromatic VOCs changed minimally. Reliable breath tests must avoid forced breathing. As isoprene Exhalations mirrored FEV performances, endogenous VOCs might assure quality of lung function tests. Analysis of exhaled VOC concentrations can provide additional information on physiology of respiration and gas exchange.
Jian Kang - One of the best experts on this subject based on the ideXlab platform.
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Which Nebulizer Position Should Be Avoided? An Extended Study of Aerosol Delivery and Ventilator Performance during Noninvasive Positive Pressure Ventilation
Respiration, 2017Co-Authors: Yun Peng, Bing Dai, Wei Tan, Hong-wen Zhao, Jian KangAbstract:Background: Research on the effect of nebulizer location on aerosol delivery during noninvasive ventilation has reached inconsistent conclusions. Objective: To investigate the effects of nebulizer position on aerosol delivery efficiency and ventilator performance during noninvasive ventilation. Methods: The Active Servo Lung 5000 respiratory simulation system (ASL5000) was used to simulate a COPD patient. The noninvasive ventilator was set to the spontaneous breathing mode. Six nebulizer positions, 2 Exhalation valve types (single-arch Exhalation port and whisper swivel), 4 combinations of inspiratory and expiratory pressure, and 2 respiratory rates were used. Results: Significant differences between nebulizer positions existed in aerosol delivery (p < 0.05). Aerosol delivery efficiency was lower for nebulizer locations on either side of the Exhalation valve and next to the ventilator outlet. When the nebulizer was located between the Exhalation valve and the simulated lung, increased inspiratory pressure increased and increased expiratory pressure decreased delivery efficiency (both p < 0.05). When the nebulization device was located between the Exhalation valve and the ventilator, no obvious trend was observed. Compared to baseline, nebulization lowered the air leakage volume displayed on the ventilator. There were no differences in ventilator performance between different nebulizer positions. Conclusions: The closer the nebulizer was to the Exhalation valves or ventilator, the lower the aerosol delivery efficiency. Nebulizer position had little clinically significant effect on ventilator performance.
Yan Shi Xie - One of the best experts on this subject based on the ideXlab platform.
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FRACTAL AND CHAOS ANALYSIS FOR DYNAMICS OF RADON Exhalation FROM URANIUM MILL TAILINGS
Fractals, 2016Co-Authors: Wanyu Tan, Kai Xuan Tan, Zehua Liu, Yan Shi XieAbstract:Tailings from mining and milling of uranium ores potentially are large volumes of low-level radioactive materials. A typical environmental problem associated with uranium tailings is radon Exhalation, which can significantly pose risks to environment and human health. In order to reduce these risks, it is essential to study the dynamical nature and underlying mechanism of radon Exhalation from uranium mill tailings. This motivates the conduction of this study, which is based on the fractal and chaotic methods (e.g. calculating the Hurst exponent, Lyapunov exponent and correlation dimension) and laboratory experiments of the radon Exhalation rates. The experimental results show that the radon Exhalation rate from uranium mill tailings is highly oscillated. In addition, the nonlinear analyses of the time series of radon Exhalation rate demonstrate the following points: (1) the value of Hurst exponent much larger than 0.5 indicates non-random behavior of the radon time series; (2) the positive Lyapunov exponent and non-integer correlation dimension of the time series imply that the radon Exhalation from uranium tailings is a chaotic dynamical process; (3) the required minimum number of variables should be five to describe the time evolution of radon Exhalation. Therefore, it can be concluded that the internal factors, including heterogeneous distribution of radium, and randomness of radium decay, as well as the fractal characteristics of the tailings, can result in the chaotic evolution of radon Exhalation from the tailings.
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Fractal Analysis of Spatial Distribution of Radon Exhalation Rates of Uranium Mill Tailings
Advanced Materials Research, 2012Co-Authors: Yan Shi Xie, Kai Xuan Tan, Liang Chen, Zheng Qing Wang, Xiu Cai WangAbstract:A uranium mill tailings, located in Guangdong, was selected for spatial distribution of the radon Exhalation rates measured by local static method. The two-dimension surface of radon Exhalation rates was established by Surfer using the data of spatial distribution of radon Exhalation rates measured at August 14, 2007 to 19 and 21, which was analyzed by fractal method of projective covering. The results show that the two-dimension surface of radon Exhalation rates is of fractal structure. The fractal dimension of surface of radon Exhalation rates from August 14, 2007 to 19 and 21 are 2.0535, 2.0173, 2.0029, 2.0084, 2.0079, 2.0057 and 2.0034, respectively, which indicates that the complexity of spatial distribution of the radon Exhalation rates at 14 and 15 are larger than that of the other days. The phenomenon results from the change of precipitation and temperature, as well as the features of uranium mill tailings, including mineral composition, particle size, radium content, porosity and pore connectivity, etc.
Y Tan - One of the best experts on this subject based on the ideXlab platform.
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No flow meter method for measuring radon Exhalation from the medium surface with a ventilation chamber
Applied radiation and isotopes : including data instrumentation and methods for use in agriculture industry and medicine, 2020Co-Authors: Y Tan, Hongzhi Yuan, Xie Yuxi, Can Liu, Xiaosong Liu, Fan Zhongkai, Kimberlee J. KearfottAbstract:The method for measuring radon Exhalation rate from the medium surface with a ventilation chamber is un-replaceable when surveying the radon Exhalation rate continuously. Generally, the pump flow rate is an important parameter to obtain the radon Exhalation rate from the measurement model. Our previous research indicated that the results of those measurements are inaccurate when the air change rate is not far larger than the effective decay constant. A no flow meter method is proposed for measuring radon Exhalation from the medium surface with a ventilation chamber. A constant K is used to replace the sum of the air change rate and the effective decay constant. The radon Exhalation rate and the value of K can be obtained by nonlinear data fitting through a novel model. The air flow rate is not a parameter of this model, and the flow meter is unnecessary in this measurement. The radon Exhalation rates obtained by verification experiments are within the accepted values for the reference value. This method can be applied to develop and improve the instruments for measuring radon Exhalation rate.
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Improving the quality of the “ventilation chamber” technique for surveying the radon Exhalation rate continuously
Stochastic Environmental Research and Risk Assessment, 2015Co-Authors: Y Tan, Hiromi Kudo-yokota, Chanis Pornnumpa, Paitoon WanabongseAbstract:The “ventilation chamber” technique is unreplaceable when the radon Exhalation rate is surveyed continuously. The air pressure difference between the chamber and the environment that leads the increase of radon Exhalation rate can be reduced by increasing the diameter of the air input tube. A sufficient condition for a standard measurement is the air change rate has to be far larger than the effective decay constant in the measurement. When the sufficient condition is false, the measured value of the radon Exhalation rate from the custom model is incorrect and it decreases with the air change rate. A new model is proposed to obtain the effective decay constant and the real radon Exhalation rate. The influence of thoron on the radon monitor without discrimination ability of the thoron increases with the flow rate. Finally, another sufficient condition is proposed to obtain the radon Exhalation rate when the radon distribution in the chamber is inhomogeneous but steady.
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Measurement of the radon Exhalation rate from the medium surface by tracing the radon concentration
Journal of Radioanalytical and Nuclear Chemistry, 2012Co-Authors: Y Tan, Detao XiaoAbstract:The paper will present a method based on the accumulation chamber technique for measuring of radon Exhalation from the medium surface. A radon monitor traces the change of radon concentration in the accumulation chamber, and then the radon Exhalation can be obtained accurately through linear fit. Based on our recent experiments, the radon Exhalation rate from the medium surface obtained from this method is in good agreement with the actual Exhalation rate of our simulation facility. This method is superior to the competition method which obtains the radon Exhalation through the exponential fit by an external PC-system. The calculation for the exponential fit is very easy by computer and related software. However, for portable instruments, the single chip microcomputer can’t calculate the exponential fit rapidly. Thus, this method is usable for developing the new portable instrument to classify building materials, etc.
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Measuring radon Exhalation rate through three cycles
Journal of Instrumentation, 2012Co-Authors: Y Tan, Detao XiaoAbstract:This paper proposes that the radon Exhalation rate can be calculated through three measurement cycles performed by a radon monitor based on the electrostatic collection method. The first cycle time is 20 min, the measured value in this cycle falls into disuse. The radon concentrations in the next two long cycles can be accurately measured. Because the 218Po concentration in the internal cell of the RAD7 is only dependent on the radon Exhalation rate and the effective decay constant of radon, the radon Exhalation can be obtained through two accurately measured values. The two equations that express the measured value in the second and third cycle can't be solved for the variable of radon Exhalation rate. However, the numerical root of the radon Exhalation rate can be searched. The radon Exhalation rates are in good agreement with the reference value (1.48±0.05 Bqm−2s−1). This method can be applied to develop and improve instruments for measuring the radon Exhalation rate.
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Revision for Measuring the Radon Exhalation Rate From the Medium Surface
IEEE Transactions on Nuclear Science, 2011Co-Authors: Y Tan, Detao XiaoAbstract:The radon Exhalation rate from the medium surface is commonly derived using a scheme involving a radon detector and an accumulation chamber. The accumulation chamber accumulates the radon gas to make its concentration level inside the chamber detectable by the radon detector in the scheme. The common calculation method for deriving the Exhalation rate is based on an assumption that the radon concentrations in the detector's internal cell and that in the accumulation chamber become equal with sufficient accumulation time. However, based on our recent experiments, this method tends to underestimate the actual Exhalation rates as generated by our simulation facility. To correct this, we develop a new method for computing the Exhalation rate based on the non-equilibrium concept. This paper presents the new method.
Yun Peng - One of the best experts on this subject based on the ideXlab platform.
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Which Nebulizer Position Should Be Avoided? An Extended Study of Aerosol Delivery and Ventilator Performance during Noninvasive Positive Pressure Ventilation
Respiration, 2017Co-Authors: Yun Peng, Bing Dai, Wei Tan, Hong-wen Zhao, Jian KangAbstract:Background: Research on the effect of nebulizer location on aerosol delivery during noninvasive ventilation has reached inconsistent conclusions. Objective: To investigate the effects of nebulizer position on aerosol delivery efficiency and ventilator performance during noninvasive ventilation. Methods: The Active Servo Lung 5000 respiratory simulation system (ASL5000) was used to simulate a COPD patient. The noninvasive ventilator was set to the spontaneous breathing mode. Six nebulizer positions, 2 Exhalation valve types (single-arch Exhalation port and whisper swivel), 4 combinations of inspiratory and expiratory pressure, and 2 respiratory rates were used. Results: Significant differences between nebulizer positions existed in aerosol delivery (p < 0.05). Aerosol delivery efficiency was lower for nebulizer locations on either side of the Exhalation valve and next to the ventilator outlet. When the nebulizer was located between the Exhalation valve and the simulated lung, increased inspiratory pressure increased and increased expiratory pressure decreased delivery efficiency (both p < 0.05). When the nebulization device was located between the Exhalation valve and the ventilator, no obvious trend was observed. Compared to baseline, nebulization lowered the air leakage volume displayed on the ventilator. There were no differences in ventilator performance between different nebulizer positions. Conclusions: The closer the nebulizer was to the Exhalation valves or ventilator, the lower the aerosol delivery efficiency. Nebulizer position had little clinically significant effect on ventilator performance.