42 CFR 84.172 - Breathing tubes; minimum requirements.

Code of Federal Regulations, 2013 CFR

2013-10-01

...) Restriction of free head movement; (b) Disturbance of the fit of facepieces, mouthpieces, hoods, or helmets; (c) Interference with the wearer's activities; and (d) Shutoff of airflow due to kinking, or from...

Development of a miniaturized diffusive sampler for true breathing-zone sampling and thermal desorption gas chromatographic analysis.

PubMed

Lindahl, Roger; Levin, Jan-Olof; Sundgren, Margit

2009-07-01

Exposure measurements should be performed as close as possible to the nose and mouth for a more correct assessment of exposure. User-friendly sampling equipment, with a minimum of handling before, during and after measurement, should not affect ordinary work. In diffusive (passive) sampling, no extra equipment as sampling pumps is needed, making the measurements more acceptable to the user. The diffusive samplers are normally attached on a shoulder, on a breast-pocket or on the lapel. There are, however, difficulties if true breathing-zone sampling is to be performed, since available diffusive samplers normally cannot be arranged close to the nose/mouth. The purpose of this work was to study the performance of a miniaturized tube type diffusive sampler attached to a headset for true breathing-zone sampling. The basis for this miniaturization was the Perkin Elmer ATD tube. Both the size of the tube and the amount of adsorbent was decreased for the miniaturized sampler. A special tube holder to be used with a headset was designed for the mini tube. The mini tube is thermally desorbed inside a standard PE tube. The new sampler was evaluated for the determination of styrene, both in laboratory experiments and in field measurements. As reference method, diffusive sampling with standard Perkin Elmer tubes, thermal desorption and gas chromatographic (GC) analysis was used. The sampling rate was determined to 0.356 mL min(-1) (CV 9.6%) and was not significantly affected by concentration, sampling time or relative humidity.

Impact of endotracheal tube shortening on work of breathing in neonatal and pediatric in vitro lung models.

PubMed

Mohr, Rebecca; Thomas, Jörg; Cannizzaro, Vincenzo; Weiss, Markus; Schmidt, Alexander R

2017-09-01

Work of breathing accounts for a significant proportion of total oxygen consumption in neonates and infants. Endotracheal tube inner diameter and length significantly affect airflow resistance and thus work of breathing. While endotracheal tube shortening reduces endotracheal tube resistance, the impact on work of breathing in mechanically ventilated neonates and infants remains unknown. The objective of this in vitro study was to quantify the effect of endotracheal tube shortening on work of breathing in simulated pediatric lung settings. We hypothesized that endotracheal tube shortening significantly reduces work of breathing. We used the Active-Servo-Lung 5000 to simulate different clinical scenarios in mechanically ventilated infants and neonates under spontaneous breathing with and without pressure support. Endotracheal tube size, lung resistance, and compliance, as well as respiratory settings such as respiratory rate and tidal volume were weight and age adapted for each lung model. Work of breathing was measured before and after maximal endotracheal tube shortening and the reduction of the daily energy demand calculated. Tube shortening with and without pressure support decreased work of breathing to a maximum of 10.1% and 8.1%, respectively. As a result, the calculated reduction of total daily energy demand by endotracheal tube shortening was between 0.002% and 0.02%. In this in vitro lung model, endotracheal tube shortening had minimal effects on work of breathing. Moreover, the calculated percentage reduction of the total daily energy demand after endotracheal tube shortening was minimal. © 2017 John Wiley & Sons Ltd.

A visual stethoscope to detect the position of the tracheal tube.

PubMed

Kato, Hiromi; Suzuki, Akira; Nakajima, Yoshiki; Makino, Hiroshi; Sanjo, Yoshimitsu; Nakai, Takayoshi; Shiraishi, Yoshito; Katoh, Takasumi; Sato, Shigehito

2009-12-01

Advancing a tracheal tube into the bronchus produces unilateral breath sounds. We created a Visual Stethoscope that allows real-time fast Fourier transformation of the sound signal and 3-dimensional (frequency-amplitude-time) color rendering of the results on a personal computer with simultaneous processing of 2 individual sound signals. The aim of this study was to evaluate whether the Visual Stethoscope can detect bronchial intubation in comparison with auscultation. After induction of general anesthesia, the trachea was intubated with a tracheal tube. The distance from the incisors to the carina was measured using a fiberoptic bronchoscope. While the anesthesiologist advanced the tracheal tube from the trachea to the bronchus, another anesthesiologist auscultated breath sounds to detect changes of the breath sounds and/or disappearance of bilateral breath sounds for every 1 cm that the tracheal tube was advanced. Two precordial stethoscopes placed at the left and right sides of the chest were used to record breath sounds simultaneously. Subsequently, at a later date, we randomly entered the recorded breath sounds into the Visual Stethoscope. The same anesthesiologist observed the visualized breath sounds on the personal computer screen processed by the Visual Stethoscope to examine changes of breath sounds and/or disappearance of bilateral breath sound. We compared the decision made based on auscultation with that made based on the results of the visualized breath sounds using the Visual Stethoscope. Thirty patients were enrolled in the study. When irregular breath sounds were auscultated, the tip of the tracheal tube was located at 0.6 +/- 1.2 cm on the bronchial side of the carina. Using the Visual Stethoscope, when there were any changes of the shape of the visualized breath sound, the tube was located at 0.4 +/- 0.8 cm on the tracheal side of the carina (P < 0.01). When unilateral breath sounds were auscultated, the tube was located at 2.6 +/- 1.2 cm on the bronchial side of the carina. The tube was also located at 2.3 +/- 1.0 cm on the bronchial side of the carina when a unilateral shape of visualized breath sounds was obtained using the Visual Stethoscope (not significant). During advancement of the tracheal tube, alterations of the shape of the visualized breath sounds using the Visual Stethoscope appeared before the changes of the breath sounds were detected by auscultation. Bilateral breath sounds disappeared when the tip of the tracheal tube was advanced beyond the carina in both groups.

49 CFR 40.267 - What problems always cause an alcohol test to be cancelled?

Code of Federal Regulations, 2012 CFR

2012-10-01

... breath tube ASD). (4) The breath tube ASD is tested with an analyzer which has not been pre-calibrated... the case of a screening test conducted on a saliva ASD or a breath tube ASD: (1) The STT or BAT reads... § 40.245(a)(8) for the saliva ASD and § 40.245(b)(8) for the breath tube ASD). (2) The saliva ASD does...

49 CFR 40.267 - What problems always cause an alcohol test to be cancelled?

Code of Federal Regulations, 2013 CFR

2013-10-01

... breath tube ASD). (4) The breath tube ASD is tested with an analyzer which has not been pre-calibrated... the case of a screening test conducted on a saliva ASD or a breath tube ASD: (1) The STT or BAT reads... § 40.245(a)(8) for the saliva ASD and § 40.245(b)(8) for the breath tube ASD). (2) The saliva ASD does...

49 CFR 40.267 - What problems always cause an alcohol test to be cancelled?

Code of Federal Regulations, 2014 CFR

2014-10-01

... breath tube ASD). (4) The breath tube ASD is tested with an analyzer which has not been pre-calibrated... the case of a screening test conducted on a saliva ASD or a breath tube ASD: (1) The STT or BAT reads... § 40.245(a)(8) for the saliva ASD and § 40.245(b)(8) for the breath tube ASD). (2) The saliva ASD does...

49 CFR 40.245 - What is the procedure for an alcohol screening test using a saliva ASD or a breath tube ASD?

Code of Federal Regulations, 2010 CFR

2010-10-01

... a breath tube ASD? (a) As the STT or BAT, you must take the following steps when using the saliva... ATF. (b) As the STT or BAT, you must take the following steps when using the breath tube ASD: (1... the manufacturer's directions. (11) You must note the fact that you used a breath tube device in Step...

Role of the superior pharyngeal constrictor muscle in forced breathing in dogs.

PubMed

Yaman, Z; Kogo, M; Senoo, H; Iida, S; Ishii, S; Matsuya, T

2000-03-01

Respiratory-related electromyographic (EMG) activity of the superior pharyngeal constrictor (SPC) muscle was analyzed during the early stage of forced breathing. Four adult dogs anesthetized with sodium pentobarbital were used. In the first part of the study, oral and nasal breathing tubes were placed into the respective cavities, and a tracheotomy tube was placed in the second part of the study. Two conditions, the presence (oral-nasal tube breathing) and absence (tracheotomy breathing) of airflow in the upper airway, were achieved in each dog. Following quiet breathing, animals were connected to a closed breathing system, first by an oral-nasal tube and then by a tracheotomy tube. We proposed to induce a forced breathing condition mechanically by using this system for 1 minute. We increased resistance to airflow during forced breathing by means of connecting tubes and a bag. Our aim was not to produce chemical drive but to produce a forced respiration by increasing the resistance to airflow. Tidal volume, breathing frequency, minute volume, chest wall movement, and EMG activity of the SPC muscle were measured and analyzed. During quiet breathing through an oral-nasal or tracheotomy tube, low-amplitude EMG activity of the SPC muscle corresponding to the expiratory cycle of the respiration was observed. In both study conditions, phasic expiratory EMG activity increased immediately after the advent of the breathing from the closed system. Tidal volumes and frequencies also increased rapidly during forced breathing. An increase in the resistance to airflow increased the activity of the SPC muscle. This augmented respiratory activity probably assists the patency of the upper airway. The augmented respiratory activity was independent of the local reflex pathways. Respiratory-related activity of the SPC muscle may help dilate and stiffen the pharyngeal airway, promoting airway patency.

Coaxial Tubing Systems Increase Artificial Airway Resistance and Work of Breathing.

PubMed

Wenzel, Christin; Schumann, Stefan; Spaeth, Johannes

2017-09-01

Tubing systems are an essential component of the ventilation circuit, connecting the ventilator to the patient's airways. Coaxial tubing systems incorporate the inspiratory tube within the lumen of the expiratory one. We hypothesized that by design, these tubing systems increase resistance to air flow compared with conventional ones. We investigated the flow-dependent pressure gradient across coaxial, conventional disposable, and conventional reusable tubing systems from 3 different manufacturers. Additionally, the additional work of breathing and perception of resistance during breathing through the different devices were determined in 18 healthy volunteers. The pressure gradient across coaxial tubing systems was up to 6 times higher compared with conventional ones (1.90 ± 0.03 cm H 2 O vs 0.34 ± 0.01 cm H 2 O, P < .001) and was higher during expiration compared with inspiration ( P < .001). Additional work of breathing and perceived breathing resistance were highest in coaxial tubing systems, accordingly. Our findings suggest that the use of coaxial tubing systems should be carefully considered with respect to their increased resistance. Copyright © 2017 by Daedalus Enterprises.

21 CFR 868.5280 - Breathing tube support.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Breathing tube support. 868.5280 Section 868.5280 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5280 Breathing tube support. (a...

21 CFR 868.5280 - Breathing tube support.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Breathing tube support. 868.5280 Section 868.5280 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5280 Breathing tube support. (a...

21 CFR 868.5280 - Breathing tube support.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Breathing tube support. 868.5280 Section 868.5280 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5280 Breathing tube support. (a...

Bronchial intubation could be detected by the visual stethoscope techniques in pediatric patients.

PubMed

Kimura, Tetsuro; Suzuki, Akira; Mimuro, Soichiro; Makino, Hiroshi; Sato, Shigehito

2012-12-01

We created a system that allows the visualization of breath sounds (visual stethoscope). We compared the visual stethoscope technique with auscultation for the detection of bronchial intubation in pediatric patients. In the auscultation group, an anesthesiologist advanced the tracheal tube, while another anesthesiologist auscultated bilateral breath sounds to detect the change and/or disappearance of unilateral breath sounds. In the visualization group, the stethoscope was used to detect changes in breath sounds and/or disappearance of unilateral breath sounds. The distance from the edge of the mouth to the carina was measured using a fiberoptic bronchoscope. Forty pediatric patients were enrolled in the study. At the point at which irregular breath sounds were auscultated, the tracheal tube was located at 0.5 ± 0.8 cm on the bronchial side from the carina. When a detectable change of shape of the visualized breath sound was observed, the tracheal tube was located 0.1 ± 1.2 cm on the bronchial side (not significant). At the point at which unilateral breath sounds were auscultated or a unilateral shape of the visualized breath sound was observed, the tracheal tube was 1.5 ± 0.8 or 1.2 ± 1.0 cm on the bronchial side, respectively (not significant). The visual stethoscope allowed to display the left and the right lung sound simultaneously and detected changes of breath sounds and unilateral breath sound as a tracheal tube was advanced. © 2012 Blackwell Publishing Ltd.

An in vitro evaluation of the influence of neonatal endotracheal tube diameter and length on the work of breathing.

PubMed

Miyake, Fuyu; Suga, Rika; Akiyama, Takahiro; Namba, Fumihiko

2018-04-06

Neonates, particularly premature babies, are often managed with endotracheal intubation and subsequent mechanical ventilation to maintain adequate pulmonary gas exchange. There is no consensus on the standard length of endotracheal tube. Although a short tube reduces resistance and respiratory dead space, it is believed to increase the risk of accidental extubation. There are not entirely coherent data regarding the effect of endotracheal tube length on work of breathing in infants. The aim of this study was to evaluate the impact of neonatal endotracheal tube diameter and length on the work of breathing using an infant in vitro lung model. We assessed the work of breathing index and mechanical ventilation settings with various endotracheal tube diameters and lengths using the JTR100 in vitro infant lung model. The basic parameters of the model were breathing frequency of 20 per minutes, inspiratory-expiratory ratio of 1:3, and positive end-expiratory pressure of 5 cmH 2 O. In addition, the diaphragm driving pressure to maintain the set tidal volume was measured as the work of breathing index. The JTR100 was connected to the Babylog 8000plus through the endotracheal tube. Finally, we monitored the peak inspiratory pressure generated during assist-control volume guarantee mode with a targeted tidal volume of 10-30 mL. The diaphragm driving pressure using a 2.0-mm inner diameter tube was twice as high as that using a 4.0-mm inner diameter tube. To maintain the targeted tidal volume, a shorter tube reduced both the diaphragm driving pressure and ventilator-generated peak inspiratory pressure. The difference in the generated peak inspiratory pressure between the shortest and longest tubes was 5 cmH 2 O. In our infant lung model, a shorter tube resulted in a lower work of breathing and lower ventilator-generated peak inspiratory pressure. © 2018 John Wiley & Sons Ltd.

Bedside diagnosis of alcohol intoxication with a pocket-size breath-alcohol device: sampling from unconscious subjects and specificity for ethanol.

PubMed

Falkensson, M; Jones, W; Sörbo, B

1989-06-01

We describe a novel mouth-cup device for sampling breath from unconscious subjects and analysis with a hand-held breath-alcohol instrument, the "Alcolmeter SD-2." This equipment was evaluated in healthy volunteers after they drank a moderate dose of alcohol. Three kinds of breath were analyzed: (a) end-expired air from a conventional mouth-tube, (b) breath sampled from the mouth-cup, and (c) air from a nasal tube supplied with the breath analyzer. The ethanol concentration in breath from the mouth-cup was slightly less than in end-expired air but significantly greater than in nasal air. Results with mouth-tube and mouth-cup correlated highly with blood-ethanol concentration as determined by gas chromatography; nasal-tube air correlated less well. The Alcolmeter responded not only to ethanol but also to methanol, 1-propanol, and 2-propanol, whereas ethylene glycol gave no response. The time-response curve for methanol was different, and this might permit differential diagnosis of methanol poisoning.

49 CFR 40.245 - What is the procedure for an alcohol screening test using a saliva ASD or a breath tube ASD?

Code of Federal Regulations, 2011 CFR

2011-10-01

... test using a saliva ASD or a breath tube ASD? 40.245 Section 40.245 Transportation Office of the... Alcohol Screening Tests § 40.245 What is the procedure for an alcohol screening test using a saliva ASD or a breath tube ASD? (a) As the STT or BAT, you must take the following steps when using the saliva...

Effect of tracheostomy tube on work of breathing: Comparison of pre- and post-decannulation.

PubMed

Villalba, Darío; Feld, Viviana; Leiva, Valeria; Scrigna, Mariana; Distéfano, Eduardo; Pratto, Romina; Rodriguez, Matías; Collins, Jesica; Rocco, Ana; Matesa, Amelia; Rossi, Damián; Areas, Laura; Virgilio, Sacha; Golfarini, Nicolás; Gil-Rosetti, Gregorio; Diaz-Ballve, Pablo; Planells, Fernando

2016-01-01

To describe and compare the work of breathing (WOB) during spontaneous breathing under four conditions: (1) breathing through a tracheostomy tube with an inflated cuff, (2) breathing through the upper airway (UA) with a deflated cuff and occluded tube, (3) breathing through the UA with an occluded cuffless tube, and (4) postdecannulation. Patients who tolerated an occluded cuffless tube were included. Ventilatory variables and esophageal pressure were recorded. The pressure-time product (PTP), PTP/min, and PTP/min/tidal volume (PTP/min/VT) were measured. Each condition was measured for 5 min with a 15 min time interval between evaluations. Quantitative data are expressed as mean ± standard deviation. Single-factor analysis of variance was used, and the Games-Howell test was used for post hoc analysis of comparisons between group means ( P ≤ 0.05). Eight patients were studied under each of the four conditions described above. Statistically significant differences were found for PTP, PTP/min, and PTP/min/VT. In the post hoc analysis for PTP, significant differences among all conditions were found. For PTP/min, there was no significant difference between Conditions 2 and 4 ( P = 0.138), and for PTP/min/VT, there was no significant difference between Conditions 1 and 2 ( P = 0.072) or between Conditions 2 and 3 ( P = 0.106). A trend toward a higher PTP, PTP/min, and PTP/min/VT was observed when breathing through a cuffless tracheostomy tube. The four conditions differed with respect to WOB. Cuff inflation could result in a reduced WOB because there is less dead space. Cuffless tracheostomy tubes generate increased WOB, perhaps due to the material deformity caused by body temperature.

Exposure to potentially toxic hydrocarbons and halocarbons released from the dialyzer and tubing set during hemodialysis.

PubMed

Lee, Hyun Ji Julie; Meinardi, Simone; Pahl, Madeleine V; Vaziri, Nostratola D; Blake, Donald R

2012-10-01

Although much is known about the effect of chronic kidney failure and dialysis on the composition of solutes in plasma, little is known about their impact on the composition of gaseous compounds in exhaled breath. This study was designed to explore the effect of uremia and the hemodialysis (HD) procedure on the composition of exhaled breath. Breath samples were collected from 10 dialysis patients immediately before, during, and after a dialysis session. To determine the potential introduction of gaseous compounds from dialysis components, gasses emitted from dialyzers, tubing set, dialysate, and water supplies were collected. Prospective cohort study. 10 HD patients and 10 age-matched healthy individuals. Predictors include the dialyzers, tubing set, dialysate, and water supplies before, during, and after dialysis. Changes in the composition of exhaled breath. A 5-column/detector gas chromatography system was used to measure hydrocarbon, halocarbon, oxygenate, and alkyl nitrate compounds. Concentrations of 14 hydrocarbons and halocarbons in patients' breath rapidly increased after the onset of the HD treatment. All 14 compounds and 5 others not found in patients' breath were emitted from the dialyzers and tubing sets. Contrary to earlier reports, exhaled breath ethane concentrations in our dialysis patients were virtually unchanged during the HD treatment. Single-center study with a small sample size may limit the generalizability of the findings. The study documented the release of several potentially toxic hydrocarbons and halocarbons to patients from the dialyzer and tubing sets during the HD procedure. Because long-term exposure to these compounds may contribute to the morbidity and mortality in dialysis population, this issue should be considered in the manufacturing of the new generation of dialyzers and dialysis tubing sets. Copyright © 2012 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

Epiglottitis

MedlinePlus

... used. This examination is best done in the operating room or a similar setting where sudden breathing problems ... (ICU). Treatment involves methods to help the person breathe, including: Breathing tube ( ...

Hydrocarbon pneumonia

MedlinePlus

... pneumonia is caused by drinking or breathing in gasoline , kerosene , furniture polish , paint thinner, or other oily ... Arterial blood gas monitoring Breathing support, including oxygen, inhalation treatment, breathing tube and ventilator (machine), in severe ...

42 CFR 84.141 - Breathing gas; minimum requirements.

Code of Federal Regulations, 2010 CFR

2010-10-01

... respirators shall be respirable breathing air and contain no less than 19.5 volume-percent of oxygen. (b... Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from American..._locations.html. (c) Compressed, liquefied breathing air shall meet the applicable minimum grade requirements...

42 CFR 84.74 - Apparatus containers; minimum requirements.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 42 Public Health 1 2011-10-01 2011-10-01 false Apparatus containers; minimum requirements. 84.74...-Contained Breathing Apparatus § 84.74 Apparatus containers; minimum requirements. (a) Apparatus may be...) Containers supplied by the applicant for carrying or storing self-contained breathing apparatus will be...

42 CFR 84.74 - Apparatus containers; minimum requirements.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 42 Public Health 1 2010-10-01 2010-10-01 false Apparatus containers; minimum requirements. 84.74...-Contained Breathing Apparatus § 84.74 Apparatus containers; minimum requirements. (a) Apparatus may be...) Containers supplied by the applicant for carrying or storing self-contained breathing apparatus will be...

42 CFR 84.87 - Compressed gas filters; minimum requirements.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 42 Public Health 1 2010-10-01 2010-10-01 false Compressed gas filters; minimum requirements. 84.87...-Contained Breathing Apparatus § 84.87 Compressed gas filters; minimum requirements. All self-contained breathing apparatus using compressed gas shall have a filter downstream of the gas source to effectively...

42 CFR 84.87 - Compressed gas filters; minimum requirements.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 42 Public Health 1 2013-10-01 2013-10-01 false Compressed gas filters; minimum requirements. 84.87...-Contained Breathing Apparatus § 84.87 Compressed gas filters; minimum requirements. All self-contained breathing apparatus using compressed gas shall have a filter downstream of the gas source to effectively...

42 CFR 84.87 - Compressed gas filters; minimum requirements.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 42 Public Health 1 2011-10-01 2011-10-01 false Compressed gas filters; minimum requirements. 84.87...-Contained Breathing Apparatus § 84.87 Compressed gas filters; minimum requirements. All self-contained breathing apparatus using compressed gas shall have a filter downstream of the gas source to effectively...

42 CFR 84.87 - Compressed gas filters; minimum requirements.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 42 Public Health 1 2012-10-01 2012-10-01 false Compressed gas filters; minimum requirements. 84.87...-Contained Breathing Apparatus § 84.87 Compressed gas filters; minimum requirements. All self-contained breathing apparatus using compressed gas shall have a filter downstream of the gas source to effectively...

42 CFR 84.87 - Compressed gas filters; minimum requirements.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 42 Public Health 1 2014-10-01 2014-10-01 false Compressed gas filters; minimum requirements. 84.87...-Contained Breathing Apparatus § 84.87 Compressed gas filters; minimum requirements. All self-contained breathing apparatus using compressed gas shall have a filter downstream of the gas source to effectively...

Adhesion of volatile propofol to breathing circuit tubing.

PubMed

Lorenz, Dominik; Maurer, Felix; Trautner, Katharina; Fink, Tobias; Hüppe, Tobias; Sessler, Daniel I; Baumbach, Jörg Ingo; Volk, Thomas; Kreuer, Sascha

2017-08-21

Propofol in exhaled breath can be measured and may provide a real-time estimate of plasma concentration. However, propofol is absorbed in plastic tubing, thus estimates may fail to reflect lung/blood concentration if expired gas is not extracted directly from the endotracheal tube. We evaluated exhaled propofol in five ventilated ICU patients who were sedated with propofol. Exhaled propofol was measured once per minute using ion mobility spectrometry. Exhaled air was sampled directly from the endotracheal tube and at the ventilator end of the expiratory side of the anesthetic circuit. The circuit was disconnected from the patient and propofol was washed out with a separate clean ventilator. Propofol molecules, which discharged from the expiratory portion of the breathing circuit, were measured for up to 60 h. We also determined whether propofol passes through the plastic of breathing circuits. A total of 984 data pairs (presented as median values, with 95% confidence interval), consisting of both concentrations were collected. The concentration of propofol sampled near the patient was always substantially higher, at 10.4 [10.25-10.55] versus 5.73 [5.66-5.88] ppb (p < 0.001). The reduction in concentration over the breathing circuit tubing was 4.58 [4.48-4.68] ppb, 3.46 [3.21-3.73] in the first hour, 4.05 [3.77-4.34] in the second hour, and 4.01 [3.36-4.40] in the third hour. Out-gassing propofol from the breathing circuit remained at 2.8 ppb after 60 h of washing out. Diffusion through the plastic was not observed. Volatile propofol binds or adsorbs to the plastic of a breathing circuit with saturation kinetics. The bond is reversible so propofol can be washed out from the plastic. Our data confirm earlier findings that accurate measurements of volatile propofol require exhaled air to be sampled as close as possible to the patient.

42 CFR 84.81 - Compressed breathing gas and liquefied breathing gas containers; minimum requirements.

Code of Federal Regulations, 2010 CFR

2010-10-01

... APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Self-Contained Breathing Apparatus § 84.81 Compressed breathing... the container. (d) Compressed breathing gas contained valves or a separate charging system or adapter...

42 CFR 84.81 - Compressed breathing gas and liquefied breathing gas containers; minimum requirements.

Code of Federal Regulations, 2014 CFR

2014-10-01

... APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Self-Contained Breathing Apparatus § 84.81 Compressed breathing... the container. (d) Compressed breathing gas contained valves or a separate charging system or adapter...

42 CFR 84.81 - Compressed breathing gas and liquefied breathing gas containers; minimum requirements.

Code of Federal Regulations, 2011 CFR

2011-10-01

... APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Self-Contained Breathing Apparatus § 84.81 Compressed breathing... the container. (d) Compressed breathing gas contained valves or a separate charging system or adapter...

42 CFR 84.81 - Compressed breathing gas and liquefied breathing gas containers; minimum requirements.

Code of Federal Regulations, 2013 CFR

2013-10-01

... APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Self-Contained Breathing Apparatus § 84.81 Compressed breathing... the container. (d) Compressed breathing gas contained valves or a separate charging system or adapter...

42 CFR 84.81 - Compressed breathing gas and liquefied breathing gas containers; minimum requirements.

Code of Federal Regulations, 2012 CFR

2012-10-01

... APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Self-Contained Breathing Apparatus § 84.81 Compressed breathing... the container. (d) Compressed breathing gas contained valves or a separate charging system or adapter...

Heat Losses from a Breathing System with a Heated-water Humidifier

PubMed Central

Lunn, J. N.; Mapleson, W. W.; Hillard, E. K.

1971-01-01

Air was “breathed” in the laboratory through a heated-water humidifier and a breathing tube. Several different humidifiers and tubes were used. The temperature rise of the air on passing through the humidifier and the temperature drop on passing through the tube were measured. Both were dependent on ventilation. Insulating the tube and humidifier together with the insertion of baffles in the latter reduced the rise and fall and their dependence on ventilation. With suitable design the dependence on ventilation and the need to use high water temperatures could be greatly reduced. In addition, a thermostat with a reduced dead zone is needed. PMID:5289685

Tracheostomy tube - speaking

MedlinePlus

... most of the air from passing through your vocal cords. Instead, your breath (air) goes out through your tracheostomy tube (trach). At the time of your surgery, the first trach tube will have a balloon ( ...

Benzene poisoning

MedlinePlus

... treated. The person may receive: Blood and urine tests. Breathing support, including a tube through the mouth into the lungs, and a breathing machine (ventilator). Chest x-ray. Endoscopy -- camera placed down ...

Breath alcohol test

MedlinePlus

... a glass tube. The tube is filled with bands of yellow crystals. The bands in the tube change colors (from yellow to ... Results Mean With the balloon method: 1 green band means that the blood-alcohol level is 0. ...

Asphalt cement poisoning

MedlinePlus

... treated. The person may receive: Blood and urine tests. Breathing support, including a tube through the mouth into the lungs, and a breathing machine (ventilator). Bronchoscopy -- camera placed down the throat to ...

Chronic Bronchitis

MedlinePlus

... bronchial tubes produce a lot of mucus. This leads to coughing and difficulty breathing. Cigarette smoking is the most common cause. Breathing in air pollution, fumes, or dust over a long period of ...

42 CFR 84.85 - Breathing bags; minimum requirements.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 42 Public Health 1 2011-10-01 2011-10-01 false Breathing bags; minimum requirements. 84.85 Section 84.85 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Self...

42 CFR 84.85 - Breathing bags; minimum requirements.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 42 Public Health 1 2014-10-01 2014-10-01 false Breathing bags; minimum requirements. 84.85 Section 84.85 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Self...

42 CFR 84.85 - Breathing bags; minimum requirements.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 42 Public Health 1 2010-10-01 2010-10-01 false Breathing bags; minimum requirements. 84.85 Section 84.85 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Self...

42 CFR 84.85 - Breathing bags; minimum requirements.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 42 Public Health 1 2013-10-01 2013-10-01 false Breathing bags; minimum requirements. 84.85 Section 84.85 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Self...

42 CFR 84.85 - Breathing bags; minimum requirements.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 42 Public Health 1 2012-10-01 2012-10-01 false Breathing bags; minimum requirements. 84.85 Section 84.85 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Self...

Design of a ram accelerator mass launch system

NASA Technical Reports Server (NTRS)

Aarnio, Michael; Armerding, Calvin; Berschauer, Andrew; Christofferson, Erik; Clement, Paul; Gohd, Robin; Neely, Bret; Reed, David; Rodriguez, Carlos; Swanstrom, Fredrick

1988-01-01

The ram accelerator mass launch system has been proposed to greatly reduce the costs of placing acceleration-insensitive payloads into low earth orbit. The ram accelerator is a chemically propelled, impulsive mass launch system capable of efficiently accelerating relatively large masses from velocities of 0.7 km/sec to 10 km/sec. The principles of propulsion are based on those of a conventional supersonic air-breathing ramjet; however the device operates in a somewhat different manner. The payload carrying vehicle resembles the center-body of the ramjet and accelerates through a stationary tube which acts as the outer cowling. The tube is filled with premixed gaseous fuel and oxidizer mixtures that burn in the vicinity of the vehicle's base, producing a thrust which accelerates the vehicle through the tube. This study examines the requirement for placing a 2000 kg vehicle into a 500 km circular orbit with a minimum amount of on-board rocket propellant for orbital maneuvers. The goal is to achieve a 50 pct payload mass fraction. The proposed design requirements have several self-imposed constraints that define the vehicle and tube configurations. Structural considerations on the vehicle and tube wall dictate an upper acceleration limit of 1000 g's and a tube inside diameter of 1.0 m. In-tube propulsive requirements and vehicle structural constraints result in a vehicle diameter of 0.76 m, a total length of 7.5 m and a nose-cone half angle of 7 degrees. An ablating nose-cone constructed from carbon-carbon composite serves as the thermal protection mechanism for atmospheric transit.

Lactose Intolerance (For Parents)

MedlinePlus

... Doctors usually diagnose lactose intolerance through a simple hydrogen breath test. A person blows into a tube ... there is a higher than average level of hydrogen and methane in the breath. That's because undigested ...

42 CFR 84.141 - Breathing gas; minimum requirements.

Code of Federal Regulations, 2013 CFR

2013-10-01

... SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Supplied-Air...) Compressed, gaseous breathing air shall meet the applicable minimum grade requirements for Type I gaseous air set forth in the Compressed Gas Association Commodity Specification for Air, G-7.1, 1966 (Grade D or...

42 CFR 84.141 - Breathing gas; minimum requirements.

Code of Federal Regulations, 2011 CFR

2011-10-01

... SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Supplied-Air...) Compressed, gaseous breathing air shall meet the applicable minimum grade requirements for Type I gaseous air set forth in the Compressed Gas Association Commodity Specification for Air, G-7.1, 1966 (Grade D or...

42 CFR 84.141 - Breathing gas; minimum requirements.

Code of Federal Regulations, 2014 CFR

2014-10-01

... SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Supplied-Air...) Compressed, gaseous breathing air shall meet the applicable minimum grade requirements for Type I gaseous air set forth in the Compressed Gas Association Commodity Specification for Air, G-7.1, 1966 (Grade D or...

42 CFR 84.141 - Breathing gas; minimum requirements.

Code of Federal Regulations, 2012 CFR

2012-10-01

... SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Supplied-Air...) Compressed, gaseous breathing air shall meet the applicable minimum grade requirements for Type I gaseous air set forth in the Compressed Gas Association Commodity Specification for Air, G-7.1, 1966 (Grade D or...

Status of selected ion flow tube MS: accomplishments and challenges in breath analysis and other areas.

PubMed

Smith, David; Španěl, Patrik

2016-06-01

This article reflects our observations of recent accomplishments made using selected ion flow tube MS (SIFT-MS). Only brief descriptions are given of SIFT-MS as an analytical method and of the recent extensions to the underpinning analytical ion chemistry required to realize more robust analyses. The challenge of breath analysis is given special attention because, when achieved, it renders analysis of other air media relatively straightforward. Brief overviews are given of recent SIFT-MS breath analyses by leading research groups, noting the desirability of detection and quantification of single volatile biomarkers rather than reliance on statistical analyses, if breath analysis is to be accepted into clinical practice. A 'strengths, weaknesses, opportunities and threats' analysis of SIFT-MS is made, which should help to increase its utility for trace gas analysis.

Evaluation of Bio-VOC Sampler for Analysis of Volatile Organic Compounds in Exhaled Breath

PubMed Central

Kwak, Jae; Fan, Maomian; Harshman, Sean W.; Garrison, Catherine E.; Dershem, Victoria L.; Phillips, Jeffrey B.; Grigsby, Claude C.; Ott, Darrin K.

2014-01-01

Monitoring volatile organic compounds (VOCs) from exhaled breath has been used to determine exposures of humans to chemicals. Prior to analysis of VOCs, breath samples are often collected with canisters or bags and concentrated. The Bio-VOC breath sampler, a commercial sampling device, has been recently introduced to the market with growing use. The main advantage for this sampler is to collect the last portion of exhaled breath, which is more likely to represent the air deep in the lungs. However, information about the Bio-VOC sampler is somewhat limited. Therefore, we have thoroughly evaluated the sampler here. We determined the volume of the breath air collected in the sampler was approximately 88 mL. When sampling was repeated multiple times, with the succeeding exhalations applied to a single sorbent tube, we observed linear relationships between the normalized peak intensity and the number of repeated collections with the sampler in many of the breath VOCs detected. No moisture effect was observed on the Tenax sorbent tubes used. However, due to the limitation in the collection volume, the use of the Bio-VOC sampler is recommended only for detection of VOCs present at high concentrations unless repeated collections of breath samples on the sampler are conducted. PMID:25532709

49 CFR 40.267 - What problems always cause an alcohol test to be cancelled?

Code of Federal Regulations, 2011 CFR

2011-10-01

... the case of a screening test conducted on a saliva ASD or a breath tube ASD: (1) The STT or BAT reads... § 40.245(a)(8) for the saliva ASD and § 40.245(b)(8) for the breath tube ASD). (2) The saliva ASD does... printed on the device or on its package (see § 40.245(a)(1) for the saliva ASD and § 40.245(b)(1) for the...

Massive gas insufflation without effect on esophageal reflectometry profiles

NASA Astrophysics Data System (ADS)

Raphael, David T.; Arnaudov, Dimiter; Benbassat, Maxim

2003-10-01

Time-domain acoustic reflectometry generates a ``one-dimensional'' image of the interior of a cavity in the form of an area-distance profile. After patient intubation with a breathing tube, the characteristic reflectometry profile consists of a constant-area segment corresponding to the length of the tube, followed either by a rapid increase in the area beyond the carina (lung) or by a sudden decrease in the area to zero (esophagus). In the cardiac arrest setting, during mistaken placement of the breathing tube into the esophagus, followed by aggressive manual ventilation, is it possible to markedly distend the esophagus, such that the esophageal profile looks like a tracheal profile? With approval of the USC IUCAC Committee, an animal study was conducted with anesthetized, tracheally intubated, and mechanically ventilated dogs. With a separate breathing tube in the esophagus, aggressive esophageal ventilation (comparable to that seen in the cardiopulmonary resuscitation setting) was accomplished with a manual resuscitation bag. A Benson Hood Labs two-microphone reflectometer was used to obtain esophageal profiles with and without the above ventilation. In this pilot study, there was no significant esophageal distention as a result of the above ventilation. [Research supported by the Alfred E. Mann Institute.

A chlorate candle/lithium hydroxide personal breathing apparatus

NASA Technical Reports Server (NTRS)

Martin, F. E.

1972-01-01

A portable coal mine rescue and survival equipment is reported that consists of a chlorate candle with a lithium hydroxide carbon-dioxide absorbent for oxygen generation, a breathing bag and tubing to conduct breathing to and from the man. A plastic hood incorporating a mouth piece for communication provides also eye protection and prevents inhalation through the nose. Manned testing of a prototype system demonstrated the feasibility of this closed circuit no-maintenance breathing apparatus that provides for good voice communication.

42 CFR 84.79 - Breathing gas; minimum requirements.

Code of Federal Regulations, 2011 CFR

2011-10-01

... SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Self... respiratory tract irritating compounds. (c) Compressed, gaseous breathing air shall meet the applicable...

42 CFR 84.79 - Breathing gas; minimum requirements.

Code of Federal Regulations, 2012 CFR

2012-10-01

... SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Self... respiratory tract irritating compounds. (c) Compressed, gaseous breathing air shall meet the applicable...

42 CFR 84.79 - Breathing gas; minimum requirements.

Code of Federal Regulations, 2014 CFR

2014-10-01

... SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Self... respiratory tract irritating compounds. (c) Compressed, gaseous breathing air shall meet the applicable...

42 CFR 84.79 - Breathing gas; minimum requirements.

Code of Federal Regulations, 2010 CFR

2010-10-01

... SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Self... respiratory tract irritating compounds. (c) Compressed, gaseous breathing air shall meet the applicable...

42 CFR 84.79 - Breathing gas; minimum requirements.

Code of Federal Regulations, 2013 CFR

2013-10-01

... SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Self... respiratory tract irritating compounds. (c) Compressed, gaseous breathing air shall meet the applicable...

Mask versus Nasal Tube for Stabilization of Preterm Infants at Birth: Respiratory Function Measurements.

PubMed

van Vonderen, Jeroen J; Kamlin, C Omar; Dawson, Jennifer A; Walther, Frans J; Davis, Peter G; te Pas, Arjan B

2015-07-01

To compare the nasal tube with face mask as interfaces for stabilization of very preterm infants at birth by using physiological measurements of leak, obstruction, and expired tidal volumes during positive pressure ventilation (PPV). In the delivery room, 43 infants <30 weeks gestation were allocated to receive respiratory support by nasal tube or face mask. Respiratory function, heart rate, and oxygen saturation were measured. Occurrence of obstruction, amount of leak, and tidal volumes were compared using a Mann-Whitney U test or a Fisher exact test. The first 5 minutes after initiation of PPV were analyzed (1566 inflations in the nasal tube group and 1896 inflations in the face mask group). Spontaneous breathing coincided with PPV in 32% of nasal tube and 34% of face mask inflations. During inflations, higher leak was observed using nasal tube compared with face mask (98% [33%-100%] vs 14 [0%-39%]; P < .0001). Obstruction occurred more often (8.2% vs 1.1%; P < .0001). Expired tidal volumes were significantly lower during inflations when using nasal tube compared with face mask (0.0 [0.0-3.1] vs 9.9 [5.5-12.8] mL/kg; P < .0001) and when spontaneous breathing coincided with PPV (4.4 [2.1-8.4] vs 9.6 [5.4-15.2] mL/kg; P < .0001) but were similar during breathing on continuous positive airway pressure (4.7 [2.8-6.9] vs 4.8 [2.7-7.9] mL/kg; P > 0.05). Heart rate was not significantly different between groups, but oxygen saturation was significantly lower in the nasal tube group the first 2 minutes after start of respiratory support. The use of a nasal tube led to large leak, more obstruction, and inadequate tidal volumes compared with face mask. Trial registration Registered with the Dutch Trial Registry (NTR 2061) and the Australia and New Zealand Clinical Trials Register (ACTRN 12610000230055). Copyright © 2015 Elsevier Inc. All rights reserved.

Visiting your baby in the NICU

MedlinePlus

... the baby. This can seem scary to new parents. They are not hurting the baby. Some tubes and wires are connected to monitors. They check the baby's breathing, heart rate, blood pressure, and temperature at all times. A tube through ...

AIRFIX: the first digital postoperative chest tube airflowmetry--a novel method to quantify air leakage after lung resection.

PubMed

Anegg, Udo; Lindenmann, Jorg; Matzi, Veronika; Mujkic, Dzenana; Maier, Alfred; Fritz, Lukas; Smolle-Jüttner, Freyja Maria

2006-06-01

Prolonged air leak after pulmonary resection is a common complication and a major limiting factor for early discharge from hospital. Currently there is little consensus on its management. The aim of this study was to develop and evaluate a measuring device which allows a simple digital bed-side quantification of air-leaks compatible to standard thoracic drainage systems. The measuring device (AIRFIX) is based upon a 'mass airflow' sensor with a specially designed software package that is connected to a thoracic suction drainage system. Its efficacy in detecting pulmonary air-leaks was evaluated in a series of 204 patients; all postoperative measurements were done under standardized conditions; the patients were asked to cough, to take a deep breath, to breathe out against the resistance of a flutter valve, to keep breath and to breathe normally. As standard parameters, the leakage per breath or cough (ml/b) as well as the leakage per minute (ml/min) were displayed and recorded on the computer. Air-leaks within a range of 0.25-45 ml/b and 5-900 ml/min were found. Removal of the chest tubes was done when leakage volume on Heimlich valve was less than 1.0 ml/b or 20 ml/min. After drain removal based upon the data from chest tube airflowmetry none of the patients needed re-drainage due to pneumothorax. The AIRFIX device for bed-side quantification of air-leaks has proved to be very simple and helpful in diagnosis and management of air-leaks after lung surgery, permitting drain removal without tentative clamping.

Use of a least absolute shrinkage and selection operator (LASSO) model to selected ion flow tube mass spectrometry (SIFT-MS) analysis of exhaled breath to predict the efficacy of dialysis: a pilot study.

PubMed

Wang, Maggie Haitian; Chong, Ka Chun; Storer, Malina; Pickering, John W; Endre, Zoltan H; Lau, Steven Yf; Kwok, Chloe; Lai, Maria; Chung, Hau Yin; Ying Zee, Benny Chung

2016-09-28

Selected ion flow tube-mass spectrometry (SIFT-MS) provides rapid, non-invasive measurements of a full-mass scan of volatile compounds in exhaled breath. Although various studies have suggested that breath metabolites may be indicators of human disease status, many of these studies have included few breath samples and large numbers of compounds, limiting their power to detect significant metabolites. This study employed a least absolute shrinkage and selective operator (LASSO) approach to SIFT-MS data of breath samples to preliminarily evaluate the ability of exhaled breath findings to monitor the efficacy of dialysis in hemodialysis patients. A process of model building and validation showed that blood creatinine and urea concentrations could be accurately predicted by LASSO-selected masses. Using various precursors, the LASSO models were able to predict creatinine and urea concentrations with high adjusted R-square (>80%) values. The correlation between actual concentrations and concentrations predicted by the LASSO model (using precursor H 3 O + ) was high (Pearson correlation coefficient  =  0.96). Moreover, use of full mass scan data provided a better prediction than compounds from selected ion mode. These findings warrant further investigations in larger patient cohorts. By employing a more powerful statistical approach to predict disease outcomes, breath analysis using SIFT-MS technology could be applicable in future to daily medical diagnoses.

Tube Law of the Pharyngeal Airway in Sleeping Patients with Obstructive Sleep Apnea.

PubMed

Genta, Pedro R; Edwards, Bradley A; Sands, Scott A; Owens, Robert L; Butler, James P; Loring, Stephen H; White, David P; Wellman, Andrew

2016-02-01

Obstructive sleep apnea (OSA) is characterized by repetitive pharyngeal collapse during sleep. However, the dynamics of pharyngeal narrowing and re-expansion during flow-limited breathing are not well described. The static pharyngeal tube law (end-expiratory area versus luminal pressure) has demonstrated increasing pharyngeal compliance as luminal pressure decreases, indicating that the airway would be sucked closed with sufficient inspiratory effort. On the contrary, the airway is rarely sucked closed during inspiratory flow limitation, suggesting that the airway is getting stiffer. Therefore, we hypothesized that during inspiratory flow limitation, as opposed to static conditions, the pharynx becomes stiffer as luminal pressure decreases. Upper airway endoscopy and simultaneous measurements of airflow and epiglottic pressure were performed during natural nonrapid eye movement sleep. Continuous positive (or negative) airway pressure was used to induce flow limitation. Flow-limited breaths were selected for airway cross-sectional area measurements. Relative airway area was quantified as a percentage of end-expiratory area. Inspiratory airway radial compliance was calculated at each quintile of epiglottic pressure versus airway area plot (tube law). Eighteen subjects (14 males) with OSA (apnea-hypopnea index = 57 ± 27 events/h), aged 49 ± 8 y, with a body mass index of 35 ± 6 kg/m(2) were studied. A total of 163 flow limited breaths were analyzed (9 ± 3 breaths per subject). Compliances at the fourth (2.0 ± 4.7 % area/cmH2O) and fifth (0.0 ± 1.7 % area/cmH2O) quintiles were significantly lower than the first (12.2 ± 5.5 % area/cmH2O) pressure quintile (P < 0.05). The pharyngeal tube law is concave (airway gets stiffer as luminal pressure decreases) during respiratory cycles under inspiratory flow limitation. © 2016 Associated Professional Sleep Societies, LLC.

The ram accelerator - A chemically driven mass launcher

NASA Technical Reports Server (NTRS)

Kaloupis, P.; Bruckner, A. P.

1988-01-01

The ram accelerator, a chemically propelled mass driver, is presented as a viable new approach for directly launching acceleration-insensitive payloads into low earth orbit. The propulsion principle is similar to that of a conventional air-breathing ramjet. The cargo vehicle resembles the center-body of a ramjet and travels through a tube filled with a pre-mixed fuel and oxidizer mixture. The launch tube acts as the outer cowling of the ramjet and the combustion process travels with the vehicle. Two drive modes of the ram accelerator propulsion system are described, which when used in sequence are capable of accelerating the vehicle to as high as 10 km/sec. The requirements are examined for placing a 2000 kg vehicle into a 500 km orbit with a minimum of on-board rocket propellant for circularization maneuvers. It is shown that aerodynamic heating during atmospheric transit results in very little ablation of the nose. An indirect orbital insertion scenario is selected, utilizing a three step maneuver consisting of two burns and aerobraking. An on-board propulsion system using storable liquid propellants is chosen in order to minimize propellant mass requirements, and the use of a parking orbit below the desired final orbit is suggested as a means to increase the flexibility of the mass launch concept. A vehicle design using composite materials is proposed that will best meet the structural requirements, and a preliminary launch tube design is presented.

Technology transfer from space to earth - The NASA Firefighter's Breathing System

NASA Technical Reports Server (NTRS)

Mclaughlan, P. B.; Anuskiewicz, T.; Keune, F. A.

1976-01-01

Responding to the recent demand of fire services for a better equipment, NASA has prepared two improved versions of Firefighter's Breathing System (FBS) by taking advantage of the spacesuit design. In the new FBS, the conventional oxygen tube is replaced by a 40% lighter air tube with twice as much pressure. The load is attached to a wide waist belt and distributed on the hips instead of the shoulder, thus making it easier to carry. The two versions of the FBS are essentially the same, the only difference being the capacities of the air tubes. Also the face mask used is smaller, lighter and provides better vision and mobility. The FBS had a notable impact, with the fire departments reporting improved efficiency. Unlike other technology transfer cases, the FBS concept is commercially successful in finding diverse fields of application.

Trajectory optimization and guidance for an aerospace plane

NASA Technical Reports Server (NTRS)

Mease, Kenneth D.; Vanburen, Mark A.

1989-01-01

The first step in the approach to developing guidance laws for a horizontal take-off, air breathing single-stage-to-orbit vehicle is to characterize the minimum-fuel ascent trajectories. The capability to generate constrained, minimum fuel ascent trajectories for a single-stage-to-orbit vehicle was developed. A key component of this capability is the general purpose trajectory optimization program OTIS. The pre-production version, OTIS 0.96 was installed and run on a Convex C-1. A propulsion model was developed covering the entire flight envelope of a single-stage-to-orbit vehicle. Three separate propulsion modes, corresponding to an after burning turbojet, a ramjet and a scramjet, are used in the air breathing propulsion phase. The Generic Hypersonic Aerodynamic Model Example aerodynamic model of a hypersonic air breathing single-stage-to-orbit vehicle was obtained and implemented. Preliminary results pertaining to the effects of variations in acceleration constraints, available thrust level and fuel specific impulse on the shape of the minimum-fuel ascent trajectories were obtained. The results show that, if the air breathing engines are sized for acceleration to orbital velocity, it is the acceleration constraint rather than the dynamic pressure constraint that is active during ascent.

Role of upper airway in ventilatory control in awake and sleeping dogs.

PubMed

Stradling, J R; England, S J; Harding, R; Kozar, L F; Andrey, S; Phillipson, E A

1987-03-01

We examined the role of the upper airway in the regulation of the pattern of breathing in six adult dogs during wakefulness and sleep. The dogs breathed through a fenestrated endotracheal tube inserted through a tracheostomy. The tube was modified to allow airflow to be directed either through the nose or through the tracheostomy. When airflow was diverted from nose to tracheostomy there was an abrupt increase in the rate of expiratory airflow, resulting in prolongation of the end-expiratory pause but no change in overall expiratory duration or respiratory frequency. Furthermore, electromyogram recordings from implanted diaphragmatic and laryngeal muscle electrodes did not show any changes that could be interpreted as an attempt to delay expiratory airflow or increase end-expiratory lung volume. The effects of switching from nose to tracheostomy breathing could be reversed by adding a resistance to the endotracheal tube so as to approximate upper airway resistance. The findings indicate that under normal conditions in the adult dog upper airway receptors play little role in regulation of respiratory pattern and that the upper airway exerts little influence on the maintenance of end-expiratory lung volume.

Mobile selected ion flow tube mass spectrometry (SIFT-MS) devices and their use for pollution exposure monitoring in breath and ambient air-pilot study.

PubMed

Storer, Malina; Salmond, Jennifer; Dirks, Kim N; Kingham, Simon; Epton, Michael

2014-09-01

Studies of health effects of air pollution exposure are limited by inability to accurately determine dose and exposure of air pollution in field trials. We explored the feasibility of using a mobile selected ion flow tube mass spectrometry (SIFT-MS) device, housed in a van, to determine ambient air and breath levels of benzene, xylene and toluene following exercise in areas of high motor vehicle traffic. The breath toluene, xylene and benzene concentration of healthy subjects were measured before and after exercising close to a busy road. The concentration of the volatile organic compounds (VOCs), in ambient air were also analysed in real time. Exercise close to traffic pollution is associated with a two-fold increase in breath VOCs (benzene, xylene and toluene) with levels returning to baseline within 20 min. This effect is not seen when exercising away from traffic pollution sources. Situating the testing device 50 m from the road reduced any confounding due to VOCs in the inspired air prior to the breath testing manoeuvre itself. Real-time field testing for air pollution exposure is possible using a mobile SIFT-MS device. This device is suitable for exploring exposure and dose relationships in a number of large scale field test scenarios.

Breathing zone air sampler

DOEpatents

Tobin, John

1989-01-01

A sampling apparatus is provided which comprises a sampler for sampling air in the breathing zone of a wearer of the apparatus and a support for the sampler preferably in the form of a pair of eyeglasses. The sampler comprises a sampling assembly supported on the frame of the eyeglasses and including a pair of sample transport tubes which are suspended, in use, centrally of the frame so as to be disposed on opposite sides of the nose of the wearer and which each include an inlet therein that, in use, is disposed adjacent to a respective nostril of the nose of the wearer. A filter holder connected to sample transport tubes supports a removable filter for filtering out particulate material in the air sampled by the apparatus. The sample apparatus is connected to a pump for drawing air into the apparatus through the tube inlets so that the air passes through the filter.

Operation and testing of Mark 10 Mod 3 underwater breathing apparatus

NASA Technical Reports Server (NTRS)

Milwee, W. I., Jr.

1972-01-01

Performance tests on a closed circuit, mixed gas underwater breathing apparatus are reported. The equipment is designed to provide a minimum diving duration of four hours at 1500 ft below sea surface; it senses oxygen partial pressure in the breathing gas mix and controls oxygen content of the breathing gas within narrow limits about a preset value. The breathing circuit subsystem provides respirable gas to the diver and removes carbon dioxide and moisture from the expired gas. Test results indicate undesirable variations in oxygen partial pressure with oxygen addition and insufficient carbon dioxide absorption.

Prediction of radial breathing-like modes of double-walled carbon nanotubes with arbitrary chirality

NASA Astrophysics Data System (ADS)

Ghavanloo, Esmaeal; Fazelzadeh, S. Ahmad

2014-10-01

The radial breathing-like modes (RBLMs) of double-walled carbon nanotubes (DWCNTs) with arbitrary chirality are investigated by a simple analytical model. For this purpose, DWCNT is considered as double concentric elastic thin cylindrical shells, which are coupled through van der Waals (vdW) forces between two adjacent tubes. Lennard-Jones potential and a molecular mechanics model are used to calculate the vdW forces and to predict the mechanical properties, respectively. The validity of these theoretical results is confirmed through the comparison of the experimental results. Finally, a new approach is proposed to determine the diameters and the chiral indices of the inner and outer tubes of the DWCNTs with high precision.

A New Differential Pressure Flow Meter for Measurement of Human Breath Flow: Simulation and Experimental Investigation

PubMed Central

Bridgeman, Devon; Tsow, Francis; Xian, Xiaojun; Forzani, Erica

2016-01-01

The development and performance characterization of a new differential pressure-based flow meter for human breath measurements is presented in this article. The device, called a “Confined Pitot Tube,” is comprised of a pipe with an elliptically shaped expansion cavity located in the pipe center, and an elliptical disk inside the expansion cavity. The elliptical disk, named Pitot Tube, is exchangeable, and has different diameters, which are smaller than the diameter of the elliptical cavity. The gap between the disk and the cavity allows the flow of human breath to pass through. The disk causes an obstruction in the flow inside the pipe, but the elliptical cavity provides an expansion for the flow to circulate around the disk, decreasing the overall flow resistance. We characterize the new sensor flow experimentally and theoretically, using Comsol Multiphysics® software with laminar and turbulent models. We also validate the sensor, using inhalation and exhalation tests and a reference method. PMID:27818521

Influence of condensing equipment and temperature on exhaled breath condensate pH, total protein and leukotriene concentrations.

PubMed

Czebe, Krisztina; Barta, Imre; Antus, Balázs; Valyon, Márta; Horváth, Ildikó; Kullmann, Tamás

2008-05-01

Exhaled breath condensate analysis is an attractive but still not fully standardised method for investigating airway pathology. Adherence of biomarkers to various condensing surfaces and changes in condensing temperature has been considered to be responsible for the variability of the results. Our aims were to compare the efficacy of different types of condensers and to test the influence of condensing temperature on condensate composition. Breath condensates from 12 healthy persons were collected in two settings: (1) by using three condensers of different type (EcoScreen, R-Tube, Anacon) and (2) by using R-Tube condenser either cooled to -20 or -70 degrees C. Condensate pH at standardised CO(2) level was determined; protein content was measured by the Bradford method and leukotrienes by EIA. Breath condensates collected using EcoScreen were more alkaline (6.45+/-0.20 vs. 6.19+/-0.23, p<0.05 and 6.10+/-0.26, p<0.001) and contained more protein (3.89+/-2.03 vs. 2.65+/-1.98, n.s. and 1.88+/-1.99 microg/ml, p<0.004) as compared to the other devices. Only parameters obtained with R-Tube and Anacon correlated. Condensing temperature affected condensate pH (5.99+/-0.20 at -20 degrees C and 5.82+/-0.07 at -70 degrees C, p<0.05) but not protein content. Leukotriene B(4) was not found in any sample and cysteinyl-leukotriene was not found in condensates collected with R-Tube or Anacon. Condenser type influences sample pH, total protein content and cysteinyl-leukotriene concentration. Condensing temperature influences condensate pH but not total protein content. These results suggest that adherence of the biomarkers to condenser surface and condensing temperature may play a role but does not fully explain the variability of EBC biomarker levels.

30 CFR 49.16 - Equipment and maintenance requirements.

Code of Federal Regulations, 2013 CFR

2013-07-01

... TRAINING MINE RESCUE TEAMS Mine Rescue Teams for Underground Coal Mines § 49.16 Equipment and maintenance... team members. (1) Twelve self-contained breathing apparatus, each with a minimum of 4 hours capacity... apparatus and sufficient to sustain each team for 8 hours while using the breathing apparatus during rescue...

30 CFR 49.16 - Equipment and maintenance requirements.

Code of Federal Regulations, 2011 CFR

2011-07-01

... TRAINING MINE RESCUE TEAMS Mine Rescue Teams for Underground Coal Mines § 49.16 Equipment and maintenance... team members. (1) Twelve self-contained breathing apparatus, each with a minimum of 4 hours capacity... apparatus and sufficient to sustain each team for 8 hours while using the breathing apparatus during rescue...

30 CFR 49.16 - Equipment and maintenance requirements.

Code of Federal Regulations, 2014 CFR

2014-07-01

... TRAINING MINE RESCUE TEAMS Mine Rescue Teams for Underground Coal Mines § 49.16 Equipment and maintenance... team members. (1) Twelve self-contained breathing apparatus, each with a minimum of 4 hours capacity... apparatus and sufficient to sustain each team for 8 hours while using the breathing apparatus during rescue...

30 CFR 49.16 - Equipment and maintenance requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... TRAINING MINE RESCUE TEAMS Mine Rescue Teams for Underground Coal Mines § 49.16 Equipment and maintenance... team members. (1) Twelve self-contained breathing apparatus, each with a minimum of 4 hours capacity... apparatus and sufficient to sustain each team for 8 hours while using the breathing apparatus during rescue...

30 CFR 49.16 - Equipment and maintenance requirements.

Code of Federal Regulations, 2012 CFR

2012-07-01

... TRAINING MINE RESCUE TEAMS Mine Rescue Teams for Underground Coal Mines § 49.16 Equipment and maintenance... team members. (1) Twelve self-contained breathing apparatus, each with a minimum of 4 hours capacity... apparatus and sufficient to sustain each team for 8 hours while using the breathing apparatus during rescue...

Hydrogen sulphide in human nasal air quantified using thermal desorption and selected ion flow tube mass spectrometry.

PubMed

Wondimu, Taddese; Wang, Rui; Ross, Brian

2014-09-01

The discovery that hydrogen sulphide (H2S) acts as a gasotransmitter when present at very low concentrations (sub-parts per billion (ppbv)) has resulted in the need to quickly quantify trace amounts of the gas in complex biological samples. Selected ion flow tube mass spectrometry (SIFT-MS) is capable of real-time quantification of H2S but many SIFT-MS instruments lack sufficient sensitivity for this application. In this study we investigate the utility of combining thermal desorption with SIFT-MS for quantifying H2S in the 0.1-1 ppbv concentration range. Human orally or nasally derived breath, and background ambient air, were collected in sampling bags and dried by passing through CaCl2 and H2S pre-concentrated using a sorbent trap optimised for the capture of this gas. The absorbed H2S was then thermally desorbed and quantified by SIFT-MS. H2S concentrations in ambient air, nasal breath and oral breath collected from 10 healthy volunteers were 0.12  ±  0.02 (mean ± SD), 0.40  ±  0.11 and 3.1  ±  2.5 ppbv respectively, and in the oral cavity H2S, quantified by SIFT-MS without pre-concentration, was present at 13.5  ±  8.6 ppbv. The oral cavity H2S correlates well with oral breath H2S but not with nasal breath H2S, suggesting that oral breath H2S derives mainly from the oral cavity but nasal breath is likely pulmonary in origin. The successful quantification of such low concentrations of H2S in nasal air using a rapid analytical procedure paves the way for the straightforward analysis of H2S in breath and may assist in elucidating the role that H2S plays in biological systems.

Fuel control for gas turbine with continuous pilot flame

DOEpatents

Swick, Robert M.

1983-01-01

An improved fuel control for a gas turbine engine having a continuous pilot flame and a fuel distribution system including a pump drawing fuel from a source and supplying a line to the main fuel nozzle of the engine, the improvement being a control loop between the pump outlet and the pump inlet to bypass fuel, an electronically controlled throttle valve to restrict flow in the control loop when main nozzle demand exists and to permit substantially unrestricted flow without main nozzle demand, a minimum flow valve in the control loop downstream of the throttle valve to maintain a minimum pressure in the loop ahead of the flow valve, a branch tube from the pilot flame nozzle to the control loop between the throttle valve and the minimum flow valve, an orifice in the branch tube, and a feedback tube from the branch tube downstream of the orifice to the minimum flow valve, the minimum flow valve being operative to maintain a substantially constant pressure differential across the orifice to maintain constant fuel flow to the pilot flame nozzle.

Automatic Tube Compensation versus Pressure Support Ventilation and Extubation Outcome in Children: A Randomized Controlled Study

PubMed Central

El-beleidy, Ahmed Saad El-din; Khattab, Asser Abd EL-Hamied; El-Sherbini, Seham Awad; Al-gebaly, Hebatalla Fadel

2013-01-01

Background. Automatic tube compensation (ATC) has been developed to overcome the imposed work of breathing due to artificial airways during spontaneous breathing trials (SBTs). Objectives. This study aimed to assess extubation outcome after an SBT (spontaneous breathing trial) with ATC compared with pressure support ventilation (PSV) and to determine the risk factors for extubation failure. Methods. Patients ready for extubation were randomly assigned to two-hour spontaneous breathing trial with either ATC or pressure support ventilation. Results. In the ATC group (n = 17), 11 (65%) patients passed the SBT with subsequent extubation failure (9%). While in PSV group (n = 19), 10 (53%) patients passed the SBT with subsequent extubation failure (10%). This represented a positive predictive value for ATC of 91% and PSV of 90% (P = 0.52). Five (83%) of the patients who failed the SBT in ATC group were reintubated. This represented a higher negative predictive value for ATC of 83% than for PSV which was 56%. None of the assessed risk factors were independently associated with extubation failure including failed trial. Conclusion. ATC was equivalent to PSV in predicting patients with successful extubation. A trial failure in ATC group is associated with but does not definitely predict extubation failure. PMID:23533800

Firefighter's compressed air breathing system pressure vessel development program

NASA Technical Reports Server (NTRS)

Beck, E. J.

1974-01-01

The research to design, fabricate, test, and deliver a pressure vessel for the main component in an improved high-performance firefighter's breathing system is reported. The principal physical and performance characteristics of the vessel which were required are: (1) maximum weight of 9.0 lb; (2) maximum operating pressure of 4500 psig (charge pressure of 4000 psig); (3) minimum contained volume of 280 in. 3; (4) proof pressure of 6750 psig; (5) minimum burst pressure of 9000 psig following operational and service life; and (6) a minimum service life of 15 years. The vessel developed to fulfill the requirements described was completely sucessful, i.e., every category of performence was satisfied. The average weight of the vessel was found to be about 8.3 lb, well below the 9.0 lb specification requirement.

Energetics of the Ventilatory Piston Pump of the Lugworm, a Deposit-feeding Polychaete Living in a Burrow.

PubMed

Toulmond, A; Dejours, P

1994-04-01

The aim of this study was to tentatively estimate the energy cost of breathing in the lugworm, Arenicola marina (L.), a gallery-dwelling, piston-pump breather that moves water in a tail-to-head direction. Each tested lugworm was placed in a horizontal glass tube. The caudal end of the tube was connected to a well-aerated seawater reservoir at 20{deg}C, and the cephalic end attached to a drop meter through a tube resistance. At the exit of the cephalic chamber the O2 tension was recorded via an in situ O2 electrode, and the hydrostatic pressure of the exhaled water was also recorded. Water flow rate, total O2 uptake rate {Mdot}TOTO2, O2 extraction coefficient, and the mechanical power necessary to pump water through the resistive anterior exit of the apparatus ({Wdot}MEC), were computed. The basal metabolic rate of each animal ({Mdot}CONFO2) was separately estimated by the confinement method. {Mdot}CONFO2 subtracted from {Mdot}TOTO2 approximates {Mdot}CBO2, the O2 uptake rate necessary to activate the piston-pump breathing mechanism and to ensure the corresponding mechanical work rate, {Wdot}MEC. The results show that the energy cost of breathing, {Mdot}CBO2, of the piston-pump-breathing Arenicola is very high, with mean values approximating 47% of the {Mdot}TOTO2 value; that the mechanical power we measured, {Wdot}MEC, is very low; and that the mechanical-to-metabolic efficiency, the ratio {Wdot}MEC/{Mdot}CBO2, does not exceed 1%. These observations are compared to those obtained in other piston-pump breathers, such as Chaetopterus variopedatus and Urechis caupo, and in ciliary filter feeders including polychaetes, bivalves, and ascidians.

Minimum wear tube support hole design

DOEpatents

Glatthorn, Raymond H.

1986-01-01

A minimum-wear through-bore (16) is defined within a heat exchanger tube support plate (14) so as to have an hourglass configuration as determined by means of a constant radiused surface curvature (18) as defined by means of an external radius (R3), wherein the surface (18) extends between the upper surface (20) and lower surface (22) of the tube support plate (14). When a heat exchange tube (12) is disposed within the tube support plate (14) so as to pass through the through-bore (16), the heat exchange tube (12) is always in contact with a smoothly curved or radiused portion of the through-bore surface (16) whereby unacceptably excessive wear upon the heat exchange tube (12), as normally developed by means of sharp edges, lands, ridges, or the like conventionally part of the tube support plates, is eliminated or substantially reduced.

Tracheostomy care

MedlinePlus

Respiratory failure - tracheostomy care; Ventilator - tracheostomy care; Respiratory insufficiency - tracheostomy care ... Before you leave the hospital, health care providers will teach you how ... and suction the tube Keep the air you breathe moist Clean ...

Prochlorperazine overdose

MedlinePlus

... AND THROAT Blurred vision Drooling Dry mouth Nasal congestion Small pupils Yellow eyes STOMACH AND INTESTINES Constipation ... symptoms Activated charcoal Laxative Breathing support, including a tube through the mouth into the lungs and connected ...

Thioridazine overdose

MedlinePlus

... AND THROAT Blurred vision Drooling Dry mouth Nasal congestion Swallowing difficulties Ulcers in the mouth, on the ... urine tests Breathing support, including oxygen and a tube through the mouth into the lungs CT scan ( ...

Nasal Cancer

MedlinePlus

... the way to your throat as you breathe. Cancer of the nasal cavity and paranasal sinuses is ... be like those of infections. Doctors diagnose nasal cancer with imaging tests, lighted tube-like instruments that ...

Treatment and Management

MedlinePlus

... measures such as placement of a breathing tube (mechanical ventilator) and administration of medications intravenously (i.e. ... be regulated. The procedure involves implanting a small mechanical device under the skin of the chest or ...

Collapsed lung (pneumothorax)

MedlinePlus

... provider will listen to your breathing with a stethoscope. If you have a collapsed lung, there are ... rupture, chest x-ray Pneumothorax - chest x-ray Respiratory system Chest tube insertion - series Pneumothorax - series References ...

Clinical comparison of a new manual toothbrush on breath volatile sulfur compounds.

PubMed

Williams, Malcolm I; Vazquez, Joe; Cummins, Diane

2004-10-01

The objective of this randomized, crossover study was to compare the effectiveness of a newly designed manual toothbrush (Colgate 360 degrees) to two commercially available manual toothbrushes (Oral-B Indicator and Oral-B CrossAction) and a battery-powered toothbrush (Crest SpinBrush PRO) for their ability to reduce overnight volatile sulfur compounds (VSC) associated with oral malodor. The study followed a four-period crossover design. Following a washout period, prospective subjects arrived at the testing facility without eating, drinking, or performing oral hygiene for baseline evaluation of breath VSC levels. For each phase of the study, subjects were given one of the test tooth-brushes and a tube of regular toothpaste to take home, and they were instructed to brush their teeth in their customary manner for 1 minute. When using the Colgate 360 degrees toothbrush, subjects were instructed to clean their tongue with the implement on the back of the brush head for 10 seconds. The following morning, subjects reported to the testing facility, again without performing oral hygiene, eating, or drinking, for the overnight evaluation. After a minimum 2-day washout period, subjects repeated the same regimen using the other toothbrushes. The levels of breath VSC were evaluated instrumentally using a gas chromatograph equipped with a flame photometric detector. Measurements were taken in duplicate and then averaged. The levels of VSC were expressed as parts per billion (ppb) in mouth air. Sixteen men and women completed the study. At baseline, the mean levels of VSC in mouth air for the 4 toothbrushes were 719.8 ppb+/-318.4 ppb, 592.8 ppb+/-264.6 ppb, 673.8 ppb+/-405.9 ppb, and 656.2 ppb+/-310.2 ppb for the Colgate 360 degrees, Oral-B Indicator, Crest SpinBrush PRO, and Oral-B CrossAction, respectively. Overnight, the mean breath VSC levels after using the four toothbrushes were lower than those observed at baseline. The respective mean levels of breath VSC were 266.5 ppb+/-269.9 ppb, 545.2 ppb+/-346.1 ppb, 567 ppb+/-335.7 ppb, and 554.6 ppb+/-398.4 ppb. Only the Colgate 360 degrees toothbrush provided a statistically significant reduction (P < .05) in breath VSC vs baseline. Additionally, the Colgate 360 degrees toothbrush was statistically significantly better (P < .05) than the three commercial toothbrushes in reducing breath VSC. Therefore, the results of this randomized, crossover clinical study indicate that a newly designed manual toothbrush with a tongue-cleaning implement on the back of the brush head was significantly more effective than three commercially available toothbrushes in reducing morning breath VSC associated with oral malodor.

A decrease in nasal CO2 stimulates breathing in the tegu lizard.

PubMed

Coates, E L; Furilla, R A; Ballam, G O; Bartlett, D

1991-10-01

Tegu lizards decrease ventilatory frequency (f) when constant CO2, as low as 0.4%, is delivered to the nasal cavities. In contrast, CO2, as high as 6%, pulsed into the nasal cavities during the expiratory phase of the breathing cycle does not alter f. The purpose of the present study was to investigate further the effect of nasal CO2 pattern on f in tegu lizards. Specifically, we tested: (1) whether f was affected by CO2 delivered to the nasal cavities during the inspiratory phase of the breathing cycle, and (2) whether pulsed decreases in nasal CO2 from 4% to 2% and from 4% to 0% would remove the f inhibition caused by constant nasal CO2. Ventilation was measured using a pneumotachograph and pressure transducer in-line with an endotracheal T-tube inserted through the glottis. CO2 was delivered to the nasal cavities through small tubes inserted into the external nares. Ventilatory frequency was not significantly altered when 4% CO2 was pulsed into the nasal cavities during inspiration. Dropping the CO2 in the nasal cavities from 4% to 0% at either 15 cycles/min (0.25 Hz) or for one cycle stimulated breathing. There was no significant difference between the f response to a drop in CO2 from 4% to 0% and that to a drop in CO2 from 4% to 2%. The failure to link the phasic CO2 ventilatory response to a phase in the respiratory cycle indicates that the nasal CO2 receptors do not participate in the breath-by-breath regulation of breathing in these lizards. The observation that small decreases in nasal CO2 abolished the f inhibition caused by constant nasal CO2 provides further evidence for the ability of the nasal CO2 receptors to distinguish between pulsed and constant CO2.

Amitriptyline and perphenazine overdose

MedlinePlus

... MOUTH Blurred vision Dry mouth Enlarged pupils Nasal congestion Unpleasant taste in mouth HEART AND BLOOD Irregular ... symptoms Activated charcoal Laxative Breathing support, including a tube through the mouth into the lungs and connected ...

Leukotriene-B4 concentrations in exhaled breath condensate and lung function after thirty minutes of breathing technically dried compressed air.

PubMed

Neubauer, Birger; Struck, Niclas; Mutzbauer, Till S; Schotte, Ulrich; Langfeldt, Norbert; Tetzlaff, Kay

2002-01-01

In previous studies it had been shown that leukotriene-B4 [LTB4] concentrations in the exhaled breath mirror the inflammatory activity of the airways if the respiratory tract has been exposed to occupational hazards. In diving the respiratory tract is exposed to cold and dry air and the nasopharynx, as the site of breathing-gas warming and humidification, is bypassed. The aim of the present study was to obtain LTB4-concentrations in the exhaled breath and spirometric data of 17 healthy subjects before and after thirty minutes of technically dried air breathing at normobar ambient pressure. The exhaled breath was collected non-invasively, via a permanently cooled expiration tube. The condensate was measured by a standard enzyme immunoassay for LTB4. Lung function values (FVC, FEV1, MEF 25, MEF 50) were simultaneously obtained by spirometry. The measured pre- and post-exposure LTB4- concentrations as well as the lung function values were in the normal range. The present data gave no evidence for any inflammatory activity in the subjects' airways after thirty minutes breathing technically dried air.

[Continuous inflation of a leaking cuff of an intubation tube].

PubMed

Boussard, N; Helmer, J; Rose, E; Lascombes, P

1988-01-01

Perforation of the cuff of the endotracheal tube peroperatively is a very serious problem, especially when it occurs in a patient prone on an orthopaedic table. This is even more dramatic when the patient is not breathing spontaneously and he cannot be turned over to be reintubated. Given the unusual character of this situation, an apparatus has been designed to keep the cuff inflated permanently. It was a circuit consisting of a manual pressure valve, flexible tubing, a peripheral catheter and the cuff supply tube. The gas used was medical air at 3 bar pressure. This method proved perfectly safe and efficient, the operation having continued without reintubation.

Chest tube insertion - series (image)

MedlinePlus

... cause the lung to collapse, such as: air leaks from the lung into the chest (pneumothorax) bleeding ... nursing staff will carefully check for possible air leaks, breathing difficulties, and need for additional oxygen. Frequent ...

Genetics Home Reference: spondylocostal dysostosis

MedlinePlus

... spina bifida and a brain abnormality called a Chiari malformation. Although breathing problems can be fatal early in ... Resources MedlinePlus (6 links) Encyclopedia: Scoliosis Health Topic: Chiari Malformation Health Topic: Neural Tube Defects Health Topic: Scoliosis ...

Critical Care Team

MedlinePlus

... to improve the health of the patient who lacks nutrients. The registered dietitian can lead or perform feedings by mouth, tube or vein. Respiratory therapist: A caregiver who has special knowledge and practice in healing patients with breathing problems. ...

Material Compatability with Threshold Limit Value Levels of Monomethyl Hydrazine

DTIC Science & Technology

1988-10-26

supply was house- compressed air conditioned by passing through a series of demisters, a hot Hopcalite catalyst bed, a reciprocating dual-tower...recorded. At the end of a test, the tubing was rinsed with methanol and dried with compressed breathing air . Cleaning the tubing material between tests had...niecessary and identify by block wbr -’Materials were evaluated for potential use as ambient air sample lines for hydrazines. Fluorinated poly- mers

An in vitro evaluation of aerosol delivery through tracheostomy and endotracheal tubes using different interfaces.

PubMed

Ari, Arzu; Harwood, Robert J; Sheard, Meryl M; Fink, James B

2012-07-01

Previous research reporting factors influencing aerosol delivery in intubated patients has been largely focused on the endotracheal tube (ETT) during mechanical ventilation, with little comparative analysis of effect of types of artificial airways and their interfaces on aerosol delivery during spontaneous breathing. The purpose of this study was to compare aerosol delivery via tracheostomy tube (TT) and ETT, using interfaces such as T-piece, tracheostomy collar, and manual resuscitation bag. A teaching manikin was intubated with either an ETT (8.0 mm inner diameter) and TT (8 mm inner diameter). Both bronchi were connected to a collecting filter, attached to a sinusoidal pump simulating the breathing pattern of a spontaneously breathing adult (tidal volume 450 mL, respiratory rate 20 breaths/min, inspiratory-expiratory ratio 1:2). Albuterol sulfate (2.5 mg/3 mL) was nebulized through a jet nebulizer, using each airway and interface as appropriate (n = 3). Drug on the filter was eluted and analyzed with spectrophotometry, and expressed as mean percent of loaded dose delivered. Descriptive statistics, the Student t test, and one-way analysis of variance were applied. A greater percentage of nominal dose was delivered via TT than ETT with both T-piece (13.79 ± 2.59% vs 9.05 ± 0.70%) and manual resuscitation bag (45.75 ± 1.8% vs 27.23 ± 8.98%, P = .038 and P = .025, respectively). Use of manual resuscitation bag with both TT and ETT increased lung dose more than 3-fold. Inhaled dose with tracheostomy collar was (6.92 ± 0.81%) less than T-piece with TT (P = .01). In this adult model of spontaneous ventilation, aerosol therapy through ETT was less efficient than TT, while the manual resuscitation bag was more efficient than T-piece or tracheostomy collar.

Saccular lung cannulation in a ball python (Python regius) to treat a tracheal obstruction.

PubMed

Myers, Debbie A; Wellehan, James F X; Isaza, Ramiro

2009-03-01

An adult male ball python (Python regius) presented in a state of severe dyspnea characterized by open-mouth breathing and vertical positioning of the head and neck. The animal had copious discharge in the tracheal lumen acting as an obstruction. A tube was placed through the body wall into the caudal saccular aspect of the lung to allow the animal to breathe while treatment was initiated. The ball python's dyspnea immediately improved. Diagnostics confirmed a bacterial respiratory infection with predominantly Providencia rettgeri. The saccular lung (air sac) tube was removed after 13 days. Pulmonary endoscopy before closure showed minimal damage with a small amount of hemorrhage in the surrounding muscle tissue. Respiratory disease is a common occurrence in captive snakes and can be associated with significant morbidity and mortality. Saccular lung cannulation is a relatively simple procedure that can alleviate tracheal narrowing or obstruction, similar to air sac cannulation in birds.

Minimum-Risk Path Finding by an Adaptive Amoebal Network

NASA Astrophysics Data System (ADS)

Nakagaki, Toshiyuki; Iima, Makoto; Ueda, Tetsuo; Nishiura, Yasumasa; Saigusa, Tetsu; Tero, Atsushi; Kobayashi, Ryo; Showalter, Kenneth

2007-08-01

When two food sources are presented to the slime mold Physarum in the dark, a thick tube for absorbing nutrients is formed that connects the food sources through the shortest route. When the light-avoiding organism is partially illuminated, however, the tube connecting the food sources follows a different route. Defining risk as the experimentally measurable rate of light-avoiding movement, the minimum-risk path is exhibited by the organism, determined by integrating along the path. A model for an adaptive-tube network is presented that is in good agreement with the experimental observations.

Effect of tubing deposition, breathing pattern, and temperature on aerosol mass distribution measured by cascade impactor.

PubMed

Gurses, Burak K; Smaldone, Gerald C

2003-01-01

Aerosols produced by nebulizers are often characterized on the bench using cascade impactors. We studied the effects of connecting tubing, breathing pattern, and temperature on mass-weighted aerodynamic particle size aerosol distributions (APSD) measured by cascade impaction. Our experimental setup consisted of a piston ventilator, low-flow (1.0 L/min) cascade impactor, two commercially available nebulizers that produced large and small particles, and two "T"-shaped tubes called "Tconnector(cascade)" and "Tconnector(nebulizer)" placed above the impactor and the nebulizer, respectively. Radiolabeled normal saline was nebulized using an airtank at 50 PSIG; APSD, mass balance, and Tconnector(cascade) deposition were measured with a gamma camera and radioisotope calibrator. Flow through the circuit was defined by the air tank (standing cloud, 10 L/min) with or without a piston pump, which superimposed a sinusoidal flow on the flow from the air tank (tidal volume and frequency of breathing). Experiments were performed at room temperature and in a cooled environment. With increasing tidal volume and frequency, smaller particles entered the cascade impactor (decreasing MMAD; e.g., Misty-Neb, 4.2 +/- 0.9 microm at lowest ventilation and 2.7 +/- 0.1 microm at highest, p = 0.042). These effects were reduced in magnitude for the nebulizer that produced smaller particles (AeroTech II, MMAD 1.8 +/- 0.1 to 1.3 +/- 0.1 microm; p = 0.0044). Deposition on Tconnector(cascade) increased with ventilation but was independent of cascade impactor flow. Imaging of the Tconnector(cascade) revealed a pattern of deposition unaffected by cascade impactor flow. These measurements suggest that changes in MMAD with ventilation were not artifacts of tubing deposition in the Tconnector(cascade). At lower temperatures, APSD distributions were more polydisperse. Our data suggest that, during patient inhalation, changes in particle distribution occur that are related to conditions in the tubing and may reduce the diameters of particles entering the patient. This effect is more significant for nebulizers producing large particles. Changes in ambient temperature did not affect these observations.

The effect of user experience and inflation technique on endotracheal tube cuff pressure using a feline airway simulator.

PubMed

White, Donna M; Redondo, José I; Mair, Alastair R; Martinez-Taboada, Fernando

2017-09-01

The effect of user experience and inflation technique on endotracheal tube cuff pressure using a feline airway simulator. Prospective, experimental clinical study. Participants included veterinary students at the beginning (group S1) and end (group S2) of their 2-week anaesthesia rotation and veterinary anaesthetists (group A). The feline airway simulator was designed to simulate an average size feline trachea, intubated with a 4.5 mm low-pressure, high-volume cuffed endotracheal tube, connected to a Bain breathing system with oxygen flow of 2 L minute -1 . Participants inflated the on-endotracheal tube cuff by pilot balloon palpation and by instilling the minimum occlusive volume (MOV) required for loss of airway leaks during manual ventilation. Intracuff pressures were measured by manometers obscured to participants and ideally were 20-30 cm H 2 O. Student t, Fisher exact, and Chi-squared tests were used where appropriate to analyse data (p < 0.05). Participants were 12 students and eight anaesthetists. Measured intracuff pressures for palpation and MOV, respectively, were 19 ± 12 and 29 ± 19 cm H 2 O for group S1, 10 ± 5 and 20 ± 11 cm H 2 O for group S2 and 13 ± 6 and 29 ± 18 cm H 2 O for group A. All groups performed poorly at achieving intracuff pressures within the ideal range. There was no significant difference in intracuff pressures between techniques. Students administered lower (p = 0.02) intracuff pressures using palpation after their training. When using palpation and MOV for cuff inflation operators rarely achieved optimal intracuff pressures. Experience had no effect on this skill and, as such, a cuff manometer is recommended. Copyright © 2017 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.

Breath analysis using external cavity diode lasers: a review

NASA Astrophysics Data System (ADS)

Bayrakli, Ismail

2017-04-01

Most techniques that are used for diagnosis and therapy of diseases are invasive. Reliable noninvasive methods are always needed for the comfort of patients. Owing to its noninvasiveness, ease of use, and easy repeatability, exhaled breath analysis is a very good candidate for this purpose. Breath analysis can be performed using different techniques, such as gas chromatography mass spectrometry (MS), proton transfer reaction-MS, and selected ion flow tube-MS. However, these devices are bulky and require complicated procedures for sample collection and preconcentration. Therefore, these are not practical for routine applications in hospitals. Laser-based techniques with small size, robustness, low cost, low response time, accuracy, precision, high sensitivity, selectivity, low detection limit, real-time, and point-of-care detection have a great potential for routine use in hospitals. In this review paper, the recent advances in the fields of external cavity lasers and breath analysis for detection of diseases are presented.

Benchtop study of leakages across the Portex, TaperGuard, and Microcuff endotracheal tubes under simulated clinical conditions.

PubMed

Lau, Arthur C W; Lam, S M; Yan, W W

2014-02-01

OBJECTIVES. To compare three endotracheal tubes for leakage across the cuff (microaspiration) under a comprehensive set of simulated clinical situations. These were the Mallinckrodt TaperGuard (Covidien, US) with a tapered polyvinyl chloride cuff; the KimVent Microcuff (Kimberly-Clark Health Care, US) with a cylindrical polyurethane cuff; and a conventional Portex (Smiths Medical International Ltd, UK) with a globular polyvinyl chloride cuff. DESIGN. A benchtop experimental study. SETTING AND MATERIALS. A silicone cylinder serving as the model trachea was intubated with each of the three endotracheal tubes, one at a time. A total of 20 mL of water were added above the cuff and leakage measured every minute for 20 minutes under five simulated mechanical ventilation scenarios, including different positive end-expiratory pressure levels, and disconnection with and without spontaneous breathing efforts. Each scenario was studied under three cuff pressures of 10, 20 and 30 cm H2O, and then repeated with the application of a continuous suction force of 200 cm H2O, and leakage measured every minute for 3 minutes. RESULTS. The outcome of interest was the cumulative amount of leakage. The Microcuff endotracheal tubes with an ultrathin polyurethane cuff consistently provided the best protection against microaspiration under all simulated clinical situations, followed by TaperGuard with a tapered cuff, and lastly Portex with a globular polyvinyl chloride cuff. Clinical scenarios associated with the greatest leakage were mechanical ventilation with zero positive end-expiratory pressure, circuit disconnection with spontaneous breathing efforts, application of suction, and a low cuff pressure. CONCLUSIONS. Microcuff endotracheal tubes outperformed TaperGuard and Portex endotracheal tubes in preventing microaspiration, which is one of the major mechanisms for ventilator-associated pneumonia.

Tracheal rupture

MedlinePlus

... collapsed lung is treated with a chest tube connected to suction, which re-expands the lung. For people who have breathed a foreign body into the airways, bronchoscopy may be used to take out the object. Antibiotics are used in people with an infection ...

Cuff deflation: rehabilitation in critical care.

PubMed

Bach, John R; Gonçalves, Miguel R; Rodriguez, Pedro Landete; Saporito, Louis; Soares, Luisa

2014-08-01

This is a case series of rehabilitation failures that resulted in severe reactive depression from patients unnecessarily bereft of verbal communication by being left to breathe or be ventilated via tracheostomy tubes, with or without inflated cuffs, for months to years.

Metal anesthesia circuit components stop the progression of laser fires.

PubMed

Sosis, M B; Braverman, B

1994-01-01

To determine whether metallic Y-pieces and elbows would halt the progression of a laser-induced endotracheal tube fire. A segment of polyvinyl chloride endotracheal tube was attached to either an all-plastic anesthesia circle breathing system (n = 5) or a circuit consisting of a metal Y-piece and elbow with plastic hoses (n = 5). In each case, an Nd-YAG laser was used to ignite the endotracheal tube segment and attached anesthesia circuit as 5 L/min of oxygen was flowing through them. Research laboratory of a university-affiliated metropolitan medical center. The flames from the endotracheal tubes burned through the 22 mm hoses that were part of the all-plastic circuits in 49.5 +/- 8.8 seconds (mean +/- SD). In none of the trials with the metal components did the fire advance beyond the endotracheal tube's 15 mm adapter. Metal circuit components halt the progression of laser-induced endotracheal tube fires toward the anesthesia machine.

Siphon flows in isolated magnetic flux tubes. V - Radiative flows with variable ionization

NASA Technical Reports Server (NTRS)

Montesinos, Benjamin; Thomas, John H.

1993-01-01

Steady siphon flows in arched isolated magnetic flux tubes in the solar atmosphere are calculated here including radiative transfer between the flux tube and its surrounding and variable ionization of the flowing gas. It is shown that the behavior of a siphon flow is strongly determined by the degree of radiative coupling between the flux tube and its surroundings in the superadiabatic layer just below the solar surface. Critical siphon flows with adiabatic tube shocks in the downstream leg are calculated, illustrating the radiative relaxation of the temperature jump downstream of the shock. For flows in arched flux tubes reaching up to the temperature minimum, where the opacity is low, the gas inside the flux tube is much cooler than the surrounding atmosphere at the top of the arch. It is suggested that gas cooled by siphon flows contribute to the cool component of the solar atmosphere at the height of the temperature minimum implied by observations of the infrared CO bands at 4.6 and 2.3 microns.

Material Capability for Transport of Unsymmetrical Dimethylhydrazine

DTIC Science & Technology

1990-07-13

is shown in Figure 1. The air supply was house compressed air conditioned by passing it through a series of demisters, a hot Hopcalite catalyst bed...required to reach that value was recorded. At the end of a test, the tubing was rinsed with methanol and dried with compressed breathing air or filtered... compressed house air . Solvents such as acetone were not used as they react with hydrazines (8]. Table 2 lists the combinations of tubing length, UDMH or

Analysis of aldehydes in human exhaled breath condensates by in-tube SPME-HPLC.

PubMed

Wang, ShuLing; Hu, Sheng; Xu, Hui

2015-11-05

In this paper, polypyrrole/graphene (PPy/G) composite coating was prepared by a facile electrochemical polymerization strategy on the inner surface of a stainless steel (SS) tube. Based on the coating tube, a novel online in-tube solid-phase microextraction -high performance liquid chromatography (IT-SPME-HPLC) was developed and applied for the extraction of aldehydes in the human exhaled breath condensates (EBC). The hybrid PPy/G nanocomposite exhibits remarkable chemical and mechanical stability, high selectivity, and satisfactory extraction performance toward aldehyde compounds. Moreover, the proposed online IT-SPME-HPLC method possesses numerous superiorities, such as time and cost saving, process simplicity, high precision and sensitivity. Some parameters related to extraction efficiency were optimized systematically. Under the optimal conditions, the recoveries of the aldehyde compounds at three spiked concentration levels varied in the range of 85%-117%. Good linearity was obtained with excellent correlation coefficients (R(2)) being larger than 0.994. The relative standard deviations (n = 5) of the method ranged from 1.8% to 11.3% and the limits of detection were between 2.3 and 3.3 nmol L(-1). The successful application of the proposed method in human EBC indicated that it is a promising approach for the determination of trace aldehyde metabolites in complex EBC samples. Copyright © 2015 Elsevier B.V. All rights reserved.

Houses need to breathe--right?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sherman, Max H.

2004-10-01

Houses need to breathe, but we can no longer leave the important functions associated with ventilation to be met accidentally. A designed ventilation system must be considered as much a part of a home as its heating system. Windows are a key part of that system because they allow a quick increase in ventilation for unusual events, but neither they nor a leaky building shell can be counted on to provide minimum levels.

Mapleson's Breathing Systems.

PubMed

Kaul, Tej K; Mittal, Geeta

2013-09-01

Mapleson breathing systems are used for delivering oxygen and anaesthetic agents and to eliminate carbon dioxide during anaesthesia. They consist of different components: Fresh gas flow, reservoir bag, breathing tubes, expiratory valve, and patient connection. There are five basic types of Mapleson system: A, B, C, D and E depending upon the different arrangements of these components. Mapleson F was added later. For adults, Mapleson A is the circuit of choice for spontaneous respiration where as Mapleson D and its Bains modifications are best available circuits for controlled ventilation. For neonates and paediatric patients Mapleson E and F (Jackson Rees modification) are the best circuits. In this review article, we will discuss the structure of the circuits and functional analysis of various types of Mapleson systems and their advantages and disadvantages.

Off-line breath acetone analysis in critical illness.

PubMed

Sturney, S C; Storer, M K; Shaw, G M; Shaw, D E; Epton, M J

2013-09-01

Analysis of breath acetone could be useful in the Intensive Care Unit (ICU) setting to monitor evidence of starvation and metabolic stress. The aims of this study were to examine the relationship between acetone concentrations in breath and blood in critical illness, to explore any changes in breath acetone concentration over time and correlate these with clinical features. Consecutive patients, ventilated on controlled modes in a mixed ICU, with stress hyperglycaemia requiring insulin therapy and/or new pulmonary infiltrates on chest radiograph were recruited. Once daily, triplicate end-tidal breath samples were collected and analysed off-line by selected ion flow tube mass spectrometry (SIFT-MS). Thirty-two patients were recruited (20 males), median age 61.5 years (range 26-85 years). The median breath acetone concentration of all samples was 853 ppb (range 162-11 375 ppb) collected over a median of 3 days (range 1-8). There was a trend towards a reduction in breath acetone concentration over time. Relationships were seen between breath acetone and arterial acetone (rs = 0.64, p < 0.0001) and arterial beta-hydroxybutyrate (rs = 0.52, p < 0.0001) concentrations. Changes in breath acetone concentration over time corresponded to changes in arterial acetone concentration. Some patients remained ketotic despite insulin therapy and normal arterial glucose concentrations. This is the first study to look at breath acetone concentration in ICU patients for up to 8 days. Breath acetone concentration may be used as a surrogate for arterial acetone concentration, which may in future have a role in the modulation of insulin and feeding in critical illness.

Deodorization of garlic breath volatiles by food and food components.

PubMed

Munch, Ryan; Barringer, Sheryl A

2014-04-01

The ability of foods and beverages to reduce allyl methyl disulfide, diallyl disulfide, allyl mercaptan, and allyl methyl sulfide on human breath after consumption of raw garlic was examined. The treatments were consumed immediately following raw garlic consumption for breath measurements, or were blended with garlic prior to headspace measurements. Measurements were done using a selected ion flow tube-mass spectrometer. Chlorophyllin treatment demonstrated no deodorization in comparison to the control. Successful treatments may be due to enzymatic, polyphenolic, or acid deodorization. Enzymatic deodorization involved oxidation of polyphenolic compounds by enzymes, with the oxidized polyphenols causing deodorization. This was the probable mechanism in raw apple, parsley, spinach, and mint treatments. Polyphenolic deodorization involved deodorization by polyphenolic compounds without enzymatic activity. This probably occurred for microwaved apple, green tea, and lemon juice treatments. When pH is below 3.6, the enzyme alliinase is inactivated, which causes a reduction in volatile formation. This was demonstrated in pH-adjusted headspace measurements. However, the mechanism for volatile reduction on human breath (after volatile formation) is unclear, and may have occurred in soft drink and lemon juice breath treatments. Whey protein was not an effective garlic breath deodorant and had no enzymatic activity, polyphenolic compounds, or acidity. Headspace concentrations did not correlate well to breath treatments. © 2014 Institute of Food Technologists®

Breath alcohol analysis incorporating standardization to water vapour is as precise as blood alcohol analysis.

PubMed

Grubb, D; Rasmussen, B; Linnet, K; Olsson, S G; Lindberg, L

2012-03-10

A novel breath-alcohol analyzer based on the standardization of the breath alcohol concentration (BrAC) to the alveolar-air water vapour concentration has been developed and evaluated. The present study compares results with this particular breath analyzer with arterial blood alcohol concentrations (ABAC), the most relevant quantitative measure of brain alcohol exposure. The precision of analysis of alcohol in arterial blood and breath were determined as well as the agreement between ABAC and BrAC over time post-dosing. Twelve healthy volunteers were administered 0.6g alcohol/kg bodyweight via an orogastric tube. Duplicate breath and arterial blood samples were obtained simultaneously during the absorption, distribution and elimination phases of the alcohol metabolism with particular emphasis on the absorption phase. The precision of the breath analyzer was similar to the determination of blood alcohol concentration by headspace gas chromatography (CV 2.40 vs. 2.38%, p=0.43). The ABAC/BrAC ratio stabilized 30min post-dosing (2089±99; mean±SD). Before this the BrAC tended to underestimate the coexisting ABAC. In conclusion, breath alcohol analysis utilizing standardization of alcohol to water vapour was as precise as blood alcohol analysis, the present "gold standard" method. The BrAC reliably predicted the coexisting ABAC from 30min onwards after the intake of alcohol. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Behavioral and physiological significance of minimum resting metabolic rate in king penguins.

PubMed

Halsey, L G; Butler, P J; Fahlman, A; Woakes, A J; Handrich, Y

2008-01-01

Because fasting king penguins (Aptenodytes patagonicus) need to conserve energy, it is possible that they exhibit particularly low metabolic rates during periods of rest. We investigated the behavioral and physiological aspects of periods of minimum metabolic rate in king penguins under different circumstances. Heart rate (f(H)) measurements were recorded to estimate rate of oxygen consumption during periods of rest. Furthermore, apparent respiratory sinus arrhythmia (RSA) was calculated from the f(H) data to determine probable breathing frequency in resting penguins. The most pertinent results were that minimum f(H) achieved (over 5 min) was higher during respirometry experiments in air than during periods ashore in the field; that minimum f(H) during respirometry experiments on water was similar to that while at sea; and that RSA was apparent in many of the f(H) traces during periods of minimum f(H) and provides accurate estimates of breathing rates of king penguins resting in specific situations in the field. Inferences made from the results include that king penguins do not have the capacity to reduce their metabolism to a particularly low level on land; that they can, however, achieve surprisingly low metabolic rates at sea while resting in cold water; and that during respirometry experiments king penguins are stressed to some degree, exhibiting an elevated metabolism even when resting.

Special wrench for B-nuts reduces torque stress in tubing

NASA Technical Reports Server (NTRS)

Stein, J. A.

1970-01-01

Gear-driven torque wrench with bearing support is used to tighten B-nut connection of partially supported fluid line with minimum stress to adjacent tubing and fittings. Wrench is useful for working with weak or brittle lines such as glass tubing.

Respiratory transfer value has fail-safe feature

NASA Technical Reports Server (NTRS)

Puccinelli, A. A.; Smith, J. R., Jr.

1965-01-01

Quick-acting, remote controlled valve connects either one of two oxygen or air supplies to a breathing tube. The valve, which is fall-safe, incorporates a cammed piston arrangement that is driven by a remote controlled reversible rotary solenoid or reversible electric motor.

Tunable Quantum Spin Liquidity in the 1 /6 th-Filled Breathing Kagome Lattice

NASA Astrophysics Data System (ADS)

Akbari-Sharbaf, A.; Sinclair, R.; Verrier, A.; Ziat, D.; Zhou, H. D.; Sun, X. F.; Quilliam, J. A.

2018-06-01

We present measurements on a series of materials, Li2 In1 -xScx Mo3 O8 , that can be described as a 1 /6 th-filled breathing kagome lattice. Substituting Sc for In generates chemical pressure which alters the breathing parameter nonmonotonically. Muon spin rotation experiments show that this chemical pressure tunes the system from antiferromagnetic long range order to a quantum spin liquid phase. A strong correlation with the breathing parameter implies that it is the dominant parameter controlling the level of magnetic frustration, with increased kagome symmetry generating the quantum spin liquid phase. Magnetic susceptibility measurements suggest that this is related to distinct types of charge order induced by changes in lattice symmetry, in line with the theory of Chen et al. [Phys. Rev. B 93, 245134 (2016), 10.1103/PhysRevB.93.245134]. The specific heat for samples at intermediate Sc concentration, which have the minimum breathing parameter, show consistency with the predicted U (1 ) quantum spin liquid.

Testing limits to airflow perturbation device (APD) measurements.

PubMed

Lopresti, Erika R; Johnson, Arthur T; Koh, Frank C; Scott, William H; Jamshidi, Shaya; Silverman, Nischom K

2008-10-31

The Airflow Perturbation Device (APD) is a lightweight, portable device that can be used to measure total respiratory resistance as well as inhalation and exhalation resistances. There is a need to determine limits to the accuracy of APD measurements for different conditions likely to occur: leaks around the mouthpiece, use of an oronasal mask, and the addition of resistance in the respiratory system. Also, there is a need for resistance measurements in patients who are ventilated. Ten subjects between the ages of 18 and 35 were tested for each station in the experiment. The first station involved testing the effects of leaks of known sizes on APD measurements. The second station tested the use of an oronasal mask used in conjunction with the APD during nose and mouth breathing. The third station tested the effects of two different resistances added in series with the APD mouthpiece. The fourth station tested the usage of a flexible ventilator tube in conjunction with the APD. All leaks reduced APD resistance measurement values. Leaks represented by two 3.2 mm diameter tubes reduced measured resistance by about 10% (4.2 cmH2O.sec/L for control and 3.9 cm H2O.sec/L for the leak). This was not statistically significant. Larger leaks given by 4.8 and 6.4 mm tubes reduced measurements significantly (3.4 and 3.0 cm cmH2O.sec/L, respectively). Mouth resistance measured with a cardboard mouthpiece gave an APD measurement of 4.2 cm H2O.sec/L and mouth resistance measured with an oronasal mask was 4.5 cm H2O.sec/L; the two were not significantly different. Nose resistance measured with the oronasal mask was 7.6 cm H2O.sec/L. Adding airflow resistances of 1.12 and 2.10 cm H2O.sec/L to the breathing circuit between the mouth and APD yielded respiratory resistance values higher than the control by 0.7 and 2.0 cm H2O.sec/L. Although breathing through a 52 cm length of flexible ventilator tubing reduced the APD measurement from 4.0 cm H2O.sec/L for the control to 3.6 cm H2O.sec/L for the tube, the difference was not statistically significant. The APD can be adapted for use in ventilated, unconscious, and uncooperative patients with use of a ventilator tube and an oronasal mask without significantly affecting measurements. Adding a resistance in series with the APD mouthpiece has an additive effect on resistance measurements, and can be used for qualitative calibration. A leak size of at least the equivalent of two 3.2 mm diameter tubes can be tolerated without significantly affecting APD measurements.

42 CFR 84.75 - Half-mask facepieces, full facepieces, mouthpieces; fit; minimum requirements.

Code of Federal Regulations, 2012 CFR

2012-10-01

... RESPIRATORY PROTECTIVE DEVICES Self-Contained Breathing Apparatus § 84.75 Half-mask facepieces, full... which shall not reduce the respiratory protective qualities of the apparatus. (c) Apparatus with...

42 CFR 84.75 - Half-mask facepieces, full facepieces, mouthpieces; fit; minimum requirements.

Code of Federal Regulations, 2011 CFR

2011-10-01

... RESPIRATORY PROTECTIVE DEVICES Self-Contained Breathing Apparatus § 84.75 Half-mask facepieces, full... which shall not reduce the respiratory protective qualities of the apparatus. (c) Apparatus with...

42 CFR 84.75 - Half-mask facepieces, full facepieces, mouthpieces; fit; minimum requirements.

Code of Federal Regulations, 2010 CFR

2010-10-01

... RESPIRATORY PROTECTIVE DEVICES Self-Contained Breathing Apparatus § 84.75 Half-mask facepieces, full... which shall not reduce the respiratory protective qualities of the apparatus. (c) Apparatus with...

42 CFR 84.75 - Half-mask facepieces, full facepieces, mouthpieces; fit; minimum requirements.

Code of Federal Regulations, 2014 CFR

2014-10-01

... RESPIRATORY PROTECTIVE DEVICES Self-Contained Breathing Apparatus § 84.75 Half-mask facepieces, full... which shall not reduce the respiratory protective qualities of the apparatus. (c) Apparatus with...

42 CFR 84.75 - Half-mask facepieces, full facepieces, mouthpieces; fit; minimum requirements.

Code of Federal Regulations, 2013 CFR

2013-10-01

... RESPIRATORY PROTECTIVE DEVICES Self-Contained Breathing Apparatus § 84.75 Half-mask facepieces, full... which shall not reduce the respiratory protective qualities of the apparatus. (c) Apparatus with...

An air-breathing enzymatic cathode with extended lifetime by continuous laccase supply.

PubMed

Kipf, Elena; Sané, Sabine; Morse, Daniel; Messinger, Thorsten; Zengerle, Roland; Kerzenmacher, Sven

2018-04-22

We present a novel concept of an air-breathing enzymatic biofuel cell cathode combined with continuous supply of unpurified laccase-containing supernatant of the white-rot fungus Trametes versicolor for extended lifetime. The air-breathing cathode design obviates the need for energy-intensive active aeration. In a corresponding long-term experiment at a constant current density of 50 µA cm -2 , we demonstrated an increased lifetime of 33 days (cathode potential above 0.430 V vs. SCE), independent of enzyme degradation. The obtained data suggest that theoretically a longer lifetime is feasible. However, further engineering efforts are required to prevent clogging and fouling of the supply tubes. These results represent an important step towards the realization of enzymatic biofuel cell cathodes with extended lifetime and enhanced performance. Copyright © 2018 Elsevier Ltd. All rights reserved.

[Polytrauma with tension pneumothorax with inserted chest tube].

PubMed

Genzwürker, H V; Volz, A; Isselhorst, C; Gieser, R; Neufang, T; Roth, H; Birmelin, M; Kerger, H

2005-12-01

The authors report a case of a 25-year-old woman with a polytrauma, caused by a free fall of 12 metres in suicidal intention. Following endotracheal intubation and mechanical ventilation by an emergency physician at the scene, the patient was delivered to the emergency room of an university hospital. An ultrasonic check of the abdomen revealed free fluid in the abdominal cavity, and a rupture of liver and spleen was suspected. Since breath sounds over the right lung were diminished, a chest tube was inserted immediately in the fifth intercostal space in the anterior axillary line. About 300 millilitres of blood were drained by the tube. Shortly thereafter, a laparotomy was performed, where spleen and liver rupture were confirmed and treated. After 60 minutes, the patient developed severe hypotension coupled with ventricular tachycardia and fibrillation, and resuscitation measures had to be initiated. Since breath sounds over the right lung were missing, a tension pneumothorax was suspected and a thoracotomy performed immediately. While huge amounts of air and blood were emerging from the thoracic cavity, a rupture of the right mainstem bronchus as well as of the right pulmonary artery and vena subclavia was identified. The chest tube was found dislocated into the subcutaneous tissue. Despite of open heart compression, application of adrenaline and noradrenaline and substitution of packed red blood cells and of crystalloid and colloid solutions, all resuscitation measures failed so that the patient died shortly after on the operation table. This case illustrates first the difficulties of an adequate thoracic trauma management, particularly, when clinical symptoms are discrete, second the problems of the insertion and control of a chest tube, and third risks associated with wrong position or secondary dislocation which may include - as in our case - "masking" of severe injury patterns and delay of life-saving measures such as an immediate thoracotomy. In order to improve prognosis of patients with poly-/thoracic trauma, establishment of spiral-CT in emergency centres, routine bronchoscopy and safe handling of chest tubes may be helpful.

75 FR 11433 - Airworthiness Directives; Hawker Beechcraft Corporation Model G58 Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-11

... brake reservoir tubing and the heater fuel pump wiring for minimum clearance and installing acceptable... of a power wire shorting out on the brake reservoir tube. We are issuing this AD to detect and correct inadequate clearance of the brake reservoir tubing and the heater fuel pump wiring, which could...

Volatile organic compounds as breath biomarkers for active and passive smoking.

PubMed

Gordon, Sydney M; Wallace, Lance A; Brinkman, Marielle C; Callahan, Patrick J; Kenny, Donald V

2002-07-01

We used real-time breath measurement technology to investigate the suitability of some volatile organic compounds (VOCs) as breath biomarkers for active and passive smoking and to measure actual exposures and resulting breath concentrations for persons exposed to tobacco smoke. Experiments were conducted with five smoker/nonsmoker pairs. The target VOCs included benzene, 1,3-butadiene, and the cigarette smoke biomarker 2,5-dimethylfuran. This study includes what we believe to be the first measurements of 1,3-butadiene in smokers' and nonsmokers' breath. The 1,3-butadiene and 2,5-dimethylfuran peak levels in the smokers' breath were similar (360 and 376 microg/m(3), respectively); the average benzene peak level was 522 microg/m(3). We found higher peak values of the target chemicals and shorter residence times in the body than previously reported, probably because of the improved time resolution made possible by the continuous breath measurement method. The real-time breath analyzer also showed the presence of the chemicals after exposure in the breath of the nonsmokers, but at greatly reduced levels. Single breath samples collected in evacuated canisters and analyzed independently with gas chromatography/mass spectrometry confirmed the presence of the target compounds in the postexposure breath of the nonsmokers but indicated that there was some contamination of the breath analyzer measurements. This was likely caused by desorption of organics from condensed tar in the analyzer tubing and on the quartz fiber filter used to remove particles. We used the decay data from the smokers to estimate residence times for the target chemicals. A two-compartment exponential model generally gave a better fit to the experimental decay data from the smokers than a single-compartment model. Residence times for benzene, 1,3-butadiene, and 2,5-dimethylfuran ranged from 0.5 (1,3-butadiene) to 0.9 min (benzene) for tau1 and were essentially constant (14 min) for tau2. These findings will be useful in models of environmental tobacco smoke exposure and risk.

49 CFR 40.245 - What is the procedure for an alcohol screening test using a saliva ASD or a breath tube ASD?

Code of Federal Regulations, 2013 CFR

2013-10-01

...'s directions. The result must be read from the analyzer no earlier then the required incubation time... this section and after having waited the required amount of time directed by the manufacturer for the...

49 CFR 40.245 - What is the procedure for an alcohol screening test using a saliva ASD or a breath tube ASD?

Code of Federal Regulations, 2014 CFR

2014-10-01

...'s directions. The result must be read from the analyzer no earlier then the required incubation time... this section and after having waited the required amount of time directed by the manufacturer for the...

49 CFR 40.245 - What is the procedure for an alcohol screening test using a saliva ASD or a breath tube ASD?

Code of Federal Regulations, 2012 CFR

2012-10-01

...'s directions. The result must be read from the analyzer no earlier then the required incubation time... this section and after having waited the required amount of time directed by the manufacturer for the...

Cavity-Enhanced Absorption Spectroscopy and Photoacoustic Spectroscopy for Human Breath Analysis

NASA Astrophysics Data System (ADS)

Wojtas, J.; Tittel, F. K.; Stacewicz, T.; Bielecki, Z.; Lewicki, R.; Mikolajczyk, J.; Nowakowski, M.; Szabra, D.; Stefanski, P.; Tarka, J.

2014-12-01

This paper describes two different optoelectronic detection techniques: cavity-enhanced absorption spectroscopy and photoacoustic spectroscopy. These techniques are designed to perform a sensitive analysis of trace gas species in exhaled human breath for medical applications. With such systems, the detection of pathogenic changes at the molecular level can be achieved. The presence of certain gases (biomarkers), at increased concentration levels, indicates numerous human diseases. Diagnosis of a disease in its early stage would significantly increase chances for effective therapy. Non-invasive, real-time measurements, and high sensitivity and selectivity, capable of minimum discomfort for patients, are the main advantages of human breath analysis. At present, monitoring of volatile biomarkers in breath is commonly useful for diagnostic screening, treatment for specific conditions, therapy monitoring, control of exogenous gases (such as bacterial and poisonous emissions), as well as for analysis of metabolic gases.

Low thermal flux glass-fiber tubing for cryogenic service

NASA Technical Reports Server (NTRS)

Hall, C. A.; Spond, D. E.

1977-01-01

This paper describes analytical techniques, fabrication development, and test results for composite tubing that has many applications in aerospace and commercial cryogenic installations. Metal liner fabrication is discussed in detail with attention given to resistance-welded liners, fusion-welded liners, chem-milled tubing liners, joining tube liners and end fittings, heat treatment and leak checks. Composite overwrapping, a second method of tubing fabrication, is also discussed. Test programs and analytical correlation are considered along with composite tubing advantages such as minimum weight, thermal efficiency and safety and reliability.

Laparoscopic insertion of the Moss feeding tube.

PubMed

Albrink, M H; Hagan, K; Rosemurgy, A S

1993-12-01

Placement of enteral feeding tubes is an important part of a surgeon's skill base. Surgical insertion of feeding tubes has been performed safely for many years with very few modifications. With the recent surge in interest and applicability of other laparoscopic procedures, it is well within the skills of the average laparoscopic surgeon to insert feeding tubes. We describe herein a simple technique for the insertion of the Moss feeding tube. The procedure described has a minimum of invasion, along with simplicity, safety, and accuracy.

TH-C-18A-11: Investigating the Minimum Scan Parameters Required to Generate Free-Breathing Fast-Helical CT Scans Without Motion-Artifacts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thomas, D; Neylon, J; Dou, T

Purpose: A recently proposed 4D-CT protocol uses deformable registration of free-breathing fast-helical CT scans to generate a breathing motion model. In order to allow accurate registration, free-breathing images are required to be free of doubling-artifacts, which arise when tissue motion is greater than scan speed. This work identifies the minimum scanner parameters required to successfully generate free-breathing fast-helical scans without doubling-artifacts. Methods: 10 patients were imaged under free breathing conditions 25 times in alternating directions with a 64-slice CT scanner using a low dose fast helical protocol. A high temporal resolution (0.1s) 4D-CT was generated using a patient specific motionmore » model and patient breathing waveforms, and used as the input for a scanner simulation. Forward projections were calculated using helical cone-beam geometry (800 projections per rotation) and a GPU accelerated reconstruction algorithm was implemented. Various CT scanner detector widths and rotation times were simulated, and verified using a motion phantom. Doubling-artifacts were quantified in patient images using structural similarity maps to determine the similarity between axial slices. Results: Increasing amounts of doubling-artifacts were observed with increasing rotation times > 0.2s for 16×1mm slice scan geometry. No significant increase in doubling artifacts was observed for 64×1mm slice scan geometry up to 1.0s rotation time although blurring artifacts were observed >0.6s. Using a 16×1mm slice scan geometry, a rotation time of less than 0.3s (53mm/s scan speed) would be required to produce images of similar quality to a 64×1mm slice scan geometry. Conclusion: The current generation of 16 slice CT scanners, which are present in most Radiation Oncology departments, are not capable of generating free-breathing sorting-artifact-free images in the majority of patients. The next generation of CT scanners should be capable of at least 53mm/s scan speed in order to use a fast-helical 4D-CT protocol to generate a motion-artifact free 4D-CT. NIH R01CA096679.« less

49 CFR Appendix G to Subchapter B... - Minimum Periodic Inspection Standards

Code of Federal Regulations, 2010 CFR

2010-10-01

... or broken cable strands. (b) Improper clamps or clamping. f. Saddle-Mounts. (1) Method of attachment... axle. (6) A tube-type radial tire without radial tube stem markings. These markings include a red band around the tube stem, the word “radial” embossed in metal stems, or the word “radial” molded in rubber...

Changes in the highest frequency of breath sounds without wheezing during methacholine inhalation challenge in children.

PubMed

Habukawa, Chizu; Murakami, Katsumi; Mochizuki, Hiroyuki; Takami, Satoru; Muramatsu, Reiko; Tadaki, Hiromi; Hagiwara, Satomi; Mizuno, Takahisa; Arakawa, Hirokazu; Nagasaka, Yukio

2010-04-01

It is difficult for clinicians to identify changes in breath sounds caused by bronchoconstriction when wheezing is not audible. A breath sound analyser can identify changes in the frequency of breath sounds caused by bronchoconstriction. The present study aimed to identify the changes in the frequency of breath sounds during bronchoconstriction and bronchodilatation using a breath sound analyser. Thirty-six children (8.2 +/- 3.7 years; males : females, 22 : 14) underwent spirometry, methacholine inhalation challenge and breath sound analysis. Methacholine inhalation challenge was performed and baseline respiratory resistance, minimum dose of methacholine (bronchial sensitivity) and speed of bronchoconstriction in response to methacholine (Sm: bronchial reactivity) were calculated. The highest frequency of inspiratory breath sounds (HFI), the highest frequency of expiratory breath sounds (HFE) and the percentage change in HFI and HFE were determined. The HFI and HFE were compared before methacholine inhalation (pre-HFI and pre-HFE), when respiratory resistance reached double the baseline value (max HFI and max HFE), and after bronchodilator inhalation (post-HFI and post-HFE). Breath sounds increased during methacholine-induced bronchoconstriction. Max HFI was significantly greater than pre-HFI (P < 0.001), and decreased to the basal level after bronchodilator inhalation. Post-HFI was significantly lower than max HFI (P < 0.001). HFI and HFE were also significantly changed (P < 0.001). The percentage change in HFI showed a significant correlation with the speed of bronchoconstriction in response to methacholine (P = 0.007). Methacholine-induced bronchoconstriction significantly increased HFI, and the increase in HFI was correlated with bronchial reactivity.

Variability of breath condensate pH may contribute to the better understanding of non-allergic seasonal respiratory diseases

NASA Astrophysics Data System (ADS)

Kullmann, Tamás; Szipőcs, Annamária

2017-09-01

The seasonal variability of certain non-allergic respiratory diseases is not clearly understood. Analysis of the breath condensate, the liquid that can be collected by breathing into a cold tube, has been proposed to bring closer to the understanding of airway pathologies. It has been assumed, that (1) airway lining fluid was a stable body liquid and (2) the breath condensate samples were representative of the airway lining fluid. Research was focussed on the identification of biomarkers indicative of respiratory pathologies. Despite 30 years of extended investigations breath condensate analysis has not gained any clinical implementation so far. The pH of the condensate is the characteristic that can be determined with the highest reproducibility. The present paper shows, that contrary to the initial assumptions, breath condensate is not a representative of the airway lining fluid, and the airway lining fluid is not a stable body liquid. Condensate pH shows baseline variability and it is influenced by drinking and by the ambient temperature. The changes in condensate pH are linked to changes in airway lining fluid pH. The variability of airway lining fluid pH may explain seasonal incidence of certain non-allergic respiratory diseases such as the catching of a common cold and the increased incidence of COPD exacerbations and exercise-induced bronchoconstriction in cold periods.

Study of 5 Volatile Organic Compounds in Exhaled Breath in Chronic Obstructive Pulmonary Disease.

PubMed

Jareño-Esteban, José Javier; Muñoz-Lucas, M Ángeles; Gómez-Martín, Óscar; Utrilla-Trigo, Sergio; Gutiérrez-Ortega, Carlos; Aguilar-Ros, Antonio; Collado-Yurrita, Luis; Callol-Sánchez, Luis Miguel

2017-05-01

A major risk factor for chronic obstructive pulmonary disease (COPD) is tobacco smoke, which generates oxidative stress in airways, resulting in the production of volatile organic compounds (VOC). The purpose of this study was to identify VOCs in exhaled breath and to determine their possible use as disease biomarkers. Exhaled breath from 100 healthy volunteers, divided into 3groups (never smokers, former smokers and active smokers) and exhaled breath from 57 COPD patients were analyzed. Samples were collected using BioVOC ® devices and transferred to universal desorption tubes. Compounds were analyzed by thermal desorption, gas chromatography and mass spectrometry. VOCs analyzed were linear aldehydesand carboxylic acids. The COPD group and healthy controls (never smokers and former smokers) showed statistically significant differences in hexanal concentrations, and never smokers and the COPD group showed statistically significant differences in nonanal concentrations. Hexanal discriminates between COPD patients and healthy non-smoking controls. Nonanal discriminates between smokers and former smokers (with and without COPD) and never smokers. Copyright © 2016 SEPAR. Publicado por Elsevier España, S.L.U. All rights reserved.

Patulous Eustachian Tube Dysfunction: Patient Demographics and Comorbidities.

PubMed

Ward, Bryan K; Ashry, Yehia; Poe, Dennis S

2017-10-01

The objective is to describe a large cohort of patients presenting with patulous Eustachian tube (pET) dysfunction. Retrospective patient series. Tertiary referral center. All outpatient visits (2004-2016) that were assigned ICD9 code (381.7-Patulous Eustachian tube) were screened. Only patients with observed tympanic membrane movements during ipsilateral nasal breathing or acoustic reflex decay testing demonstrating transmitted nasal breathing were included (n = 190, n = 239 ears). Demographics and nasopharyngoscopy/otomicroscopy findings by comorbidities. The majority (54%) was female and mean age of symptom onset was 38.0 (SD 20.0) years. Common symptoms included voice autophony (93%), breath autophony (92%), aural fullness (57%), pulsatile tinnitus (17%), and crackling or rumbling sounds (14%). Symptoms increased in frequency and duration with time (65%), were exacerbated with exercise (27%), and improved with placing the head in a dependent position (65%), sniffing (28%), upper respiratory infection (8%), and ipsilateral internal jugular vein compression (12%). In 52% pET was bilateral. Common comorbidities include environmental allergy (49%), weight loss (35%), laryngopharyngeal reflux (33%), anxiety (31%), autoimmunity (13%), and neuromuscular disease (8%). Allergy and anxiety patients were younger and more likely to have tonic contraction of the tensor veli palatini on exam (p < 0.05, χ). Allergy patients also had relief with sniffing and tympanic membrane retraction (p < 0.01, χ). Weight loss patients reported mean loss of 19.7 kg (SD 23.1), and were older, more rapidly diagnosed, and more likely to have persistent symptoms (p < 0.05). Initially, all patients were treated medically, with 47% eventually electing surgical intervention. pET is progressive, often bilateral, and possibly underdiagnosed. In this large series of pET, in addition to weight loss and chronic medical conditions, allergy and stress/anxiety were identified as novel risk factors. Most patients can be treated medically.

Reference respiratory waveforms by minimum jerk model analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anetai, Yusuke, E-mail: anetai@radonc.med.osaka-u.ac.jp; Sumida, Iori; Takahashi, Yutaka

Purpose: CyberKnife{sup ®} robotic surgery system has the ability to deliver radiation to a tumor subject to respiratory movements using Synchrony{sup ®} mode with less than 2 mm tracking accuracy. However, rapid and rough motion tracking causes mechanical tracking errors and puts mechanical stress on the robotic joint, leading to unexpected radiation delivery errors. During clinical treatment, patient respiratory motions are much more complicated, suggesting the need for patient-specific modeling of respiratory motion. The purpose of this study was to propose a novel method that provides a reference respiratory wave to enable smooth tracking for each patient. Methods: The minimummore » jerk model, which mathematically derives smoothness by means of jerk, or the third derivative of position and the derivative of acceleration with respect to time that is proportional to the time rate of force changed was introduced to model a patient-specific respiratory motion wave to provide smooth motion tracking using CyberKnife{sup ®}. To verify that patient-specific minimum jerk respiratory waves were being tracked smoothly by Synchrony{sup ®} mode, a tracking laser projection from CyberKnife{sup ®} was optically analyzed every 0.1 s using a webcam and a calibrated grid on a motion phantom whose motion was in accordance with three pattern waves (cosine, typical free-breathing, and minimum jerk theoretical wave models) for the clinically relevant superior–inferior directions from six volunteers assessed on the same node of the same isocentric plan. Results: Tracking discrepancy from the center of the grid to the beam projection was evaluated. The minimum jerk theoretical wave reduced the maximum-peak amplitude of radial tracking discrepancy compared with that of the waveforms modeled by cosine and typical free-breathing model by 22% and 35%, respectively, and provided smooth tracking for radial direction. Motion tracking constancy as indicated by radial tracking discrepancy affected by respiratory phase was improved in the minimum jerk theoretical model by 7.0% and 13% compared with that of the waveforms modeled by cosine and free-breathing model, respectively. Conclusions: The minimum jerk theoretical respiratory wave can achieve smooth tracking by CyberKnife{sup ®} and may provide patient-specific respiratory modeling, which may be useful for respiratory training and coaching, as well as quality assurance of the mechanical CyberKnife{sup ®} robotic trajectory.« less

14 CFR 23.1443 - Minimum mass flow of supplemental oxygen.

Code of Federal Regulations, 2011 CFR

2011-01-01

... displaced by water vapor pressure when the breathed air becomes saturated with water vapor at 37 °C). (2) STPD means Standard, Temperature, and Pressure, Dry (which is, 0 °C at 760 mm. Hg with no water vapor...

14 CFR 23.1443 - Minimum mass flow of supplemental oxygen.

Code of Federal Regulations, 2013 CFR

2013-01-01

... displaced by water vapor pressure when the breathed air becomes saturated with water vapor at 37 °C). (2) STPD means Standard, Temperature, and Pressure, Dry (which is 0 °C at 760mm Hg with no water vapor...

14 CFR 23.1443 - Minimum mass flow of supplemental oxygen.

Code of Federal Regulations, 2014 CFR

2014-01-01

... displaced by water vapor pressure when the breathed air becomes saturated with water vapor at 37 °C). (2) STPD means Standard, Temperature, and Pressure, Dry (which is 0 °C at 760mm Hg with no water vapor...

Optimization and Dose Estimation of Aerosol Delivery to Non-Human Primates.

PubMed

MacLoughlin, Ronan J; van Amerongen, Geert; Fink, James B; Janssens, Hettie M; Duprex, W Paul; de Swart, Rik L

2016-06-01

In pre-clinical animal studies, the uniformity of dosing across subjects and routes of administration is a crucial requirement. In preparation for a study in which aerosolized live-attenuated measles virus vaccine was administered to cynomolgus monkeys (Macaca fascicularis) by inhalation, we assessed the percentage of a nebulized dose inhaled under varying conditions. Drug delivery varies with breathing parameters. Therefore we determined macaque breathing patterns (tidal volume, breathing frequency, and inspiratory to expiratory (I:E) ratio) across a range of 3.3-6.5 kg body weight, using a pediatric pneumotachometer interfaced either with an endotracheal tube or a facemask. Subsequently, these breathing patterns were reproduced using a breathing simulator attached to a filter to collect the inhaled dose. Albuterol was nebulized using a vibrating mesh nebulizer and the percentage inhaled dose was determined by extraction of drug from the filter and subsequent quantification. Tidal volumes ranged from 24 to 46 mL, breathing frequencies from 19 to 31 breaths per minute and I:E ratios from 0.7 to 1.6. A small pediatric resuscitation mask was identified as the best fitting interface between animal and pneumotachometer. The average efficiency of inhaled dose delivery was 32.1% (standard deviation 7.5, range 24%-48%), with variation in tidal volumes as the most important determinant. Studies in non-human primates aimed at comparing aerosol delivery with other routes of administration should take both the inter-subject variation and relatively low efficiency of delivery to these low body weight mammals into account.

Towards Breath Gas Analysis Based on Millimeter-Wave Molecular Spectroscopy

NASA Astrophysics Data System (ADS)

Rothbart, Nick; Hübers, Heinz-Wilhelm; Schmalz, Klaus; Borngräber, Johannes; Kissinger, Dietmar

2018-03-01

Breath gas analysis is a promising non-invasive tool for medical diagnosis as there are thousands of Volatile Organic Compounds (VOCs) in human breath that can be used as health monitoring markers. Millimeter-wave/terahertz molecular spectroscopy is highly suitable for breath gas analysis due to unique fingerprint spectra of many VOCs in that frequency range. We present our recent work on sensor systems for gas spectroscopy based on integrated transmitters (TX) and receivers (RX) fabricated in IHP's 0.13 μm SiGe BiCMOS technology. For a single-band system, spectroscopic measurements and beam profiles are presented. The frequency is tuned by direct voltage-frequency tuning and by a fractional-n PLL, respectively. The spectroscopic system includes a folded gas absorption cell with gas pre-concentration abilities demonstrating the detection of a 50 ppm mixture of ethanol in ambient air corresponding to a minimum detectable concentration of 260 ppb. Finally, the design of a 3-band system covering frequencies from 225 to 273 GHz is introduced.

An improved technique for studying pleural fluid pressure and composition in rabbits.

PubMed

Del Fabbro, M

1998-07-01

Knowledge of pleural liquid pressure (Pliq) and composition is crucial for studies concerning intrapleural fluid dynamics, and pleural fluid turnover. We measured Pliq at intercostal and costal levels in anaesthetized spontaneously breathing rabbits using a minimally invasive method that assures a long-lasting hydraulic continuity between the pleural liquid and the recording system. Polyethylene tubes were glued either to the exposed endothoracic fascia or inserted into a rib to provide a scaled connection to the recording system. After inducing a pneumothorax with nitrous oxide (N2O) via an intrapleural cannula, a hole (approximately 0.7 mm2) was pierced in the parietal pleura through the tube lumen. The tubes were then connected to pressure transducers and the whole system was filled with heparinized saline to the level of the parietal pleura; finally the pneumo-thorax was removed after N2O washout and Pliq recordings were performed. A different kind of tube was used to obtain microsamples of pleural fluid (2.5-3 microliters) during spontaneous breathing; colloid osmotic pressure of the microsamples (pi liq) was measured with an osmometer, and averaged 9.3 +/- 1.5 cm H2o (n = 70 samples). When pooled and plotted against lung height end-expiratory intercostal and costal Pliq data scattered along a single regression line with a slope of -0.83 and -0.90 cm H2O cm(-1) in supine and prone animals, respectively. End-inspiratory costal Pliq was significantly more subatmospheric than intercostal in the ventral region of the chest (P < 0.05), and less subatmospheric in the dorsal region, regardless of posture. The techniques presented here could be helpful in gaining a greater insight into the physiology and pathophysiology of the pleural space in terms of pleural fluid dynamics and turnover.

Estimating Fluctuating Pressures From Distorted Measurements

NASA Technical Reports Server (NTRS)

Whitmore, Stephen A.; Leondes, Cornelius T.

1994-01-01

Two algorithms extract estimates of time-dependent input (upstream) pressures from outputs of pressure sensors located at downstream ends of pneumatic tubes. Effect deconvolutions that account for distoring effects of tube upon pressure signal. Distortion of pressure measurements by pneumatic tubes also discussed in "Distortion of Pressure Signals in Pneumatic Tubes," (ARC-12868). Varying input pressure estimated from measured time-varying output pressure by one of two deconvolution algorithms that take account of measurement noise. Algorithms based on minimum-covariance (Kalman filtering) theory.

A dryer for rapid response on-line expired gas measurements.

PubMed

Deno, N S; Kamon, E

1979-06-01

A dryer is described for use in on-line breath-by-breath gas analysis systems. The dryer continuously removes water vapor by condensation and controls the sample gas at 2 degrees C dew-point temperature or 5 Torr water vapor partial pressure. It is designed to operate at gas sampling flow rates from 0.5 to 1 1.min-1. The step-response time for the described system including a Beckman LB-2 CO2 analyzer, sampling tubing, and dryer is 120 ms at 1 l.min-1. The time required for gas samples to transport through the dryer is 105 ms at a gas sampling-flow rate of 1 l.min=1.

Waste anesthetic gas exposures to veterinarians and animal technicians

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wingfield, W.E.; Ruby, D.L.; Buchan, R.M.

1981-02-15

A survey of veterinarians was conducted in an 11-county region of eastern Colorado to determine the extent of usage of inhalation anesthetics and to measure exposures of veterinarians and their assistants to waste anesthetic gases. The survey indicated that inhalation anesthetics were used in 80.8% of the 210 practices. Exposures to waste anesthetics in veterinary practices were far less than reported in human hospitals. Waste anesthetic concentrations were affected by size of the patient, type of breathing system, and use of scavenging systems. Dilution ventilation had no effect on breathing zone concentrations. The endotracheal tube and occasionally the anesthetic machinemore » were the major sources of leakage of anesthetic gases.« less

SU-F-J-117: Impact of Motion Artifacts On Image Quality and Accuracy of Tumor Motion Reconstruction in 4D CT-On-Rails and MV-CBCT Scans: A Phantom Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, T; Ma, C

Purpose: To compare and quantify respiratory motion artifacts in images from free breathing 4D-CT-on-Rails(CTOR) and those from MV-Cone-beam-CT(MVCB) and facilitate respiratory motion guided radiation therapy. Methods: 4D-CTOR: Siemens Somatom CT-on-Rails system with Anzai belt loaded with pressure sensor load cells. 4D scans were performed in helical mode, pitch 0.1, gantry rotation time 0.5s, 1.5mm slice thickness, 120kVp, 400 mAs. Normal and fast breathing (>12rpm) scanning protocols were investigated. Helical scan, AIP(average intensity projection) and MIP(maximum intensity projection) were generated from 4D-CTOR scans with amplitude sorting into 10 phases.MVCB: Siemens Artiste diamond view(1MV)MVCB was performed with 5MU thorax protocol with 60more » second of full rotation.Phantom: Anzai AZ-733V respiratory phantom. The settings were set to normal and resp. modes with repetition rates at 15 rpm and 10 rpm. Surgical clips, acrylic, wooden, rubber and lung density, total six mock-ups were scanned and compared in this study.Signal-to-noise ratio(SNR), contrast-to-noise ratio(CNR) and reconstructed motion volume were compared to different respiratory setups for the mock-ups. Results: Reconstructed motion volume was compared to the real object volume for the six test mock-ups. It shows that free breathing helical in all instances underestimates the object excursions largest to −67.4% and least −6.3%. Under normal breathing settings, MIP can predict very precise motion volume with minimum 0.4% and largest −13.9%. MVCB shows underestimate of the motion volume with −1.11% minimum and −18.0% maximum. With fast breathing, AIP provides bad representation of the object motion; however, the MIP can predict the motion volume with −2.0% to −11.4% underestimate. Conclusion: Respiratory motion guided radiation therapy requires good motion recording. This study shows that regular CTOR helical scans provides bad guidance, 4D CTOR AIP cannot represent the fast breathing pattern, MIP can represent the best motion volume, MVCBCT can only be used for normal breathing with acceptable uncertainties.« less

Accuracy of the dose-shift approximation in estimating the delivered dose in SBRT of lung tumors considering setup errors and breathing motions.

PubMed

Karlsson, Kristin; Lax, Ingmar; Lindbäck, Elias; Poludniowski, Gavin

2017-09-01

Geometrical uncertainties can result in a delivered dose to the tumor different from that estimated in the static treatment plan. The purpose of this project was to investigate the accuracy of the dose calculated to the clinical target volume (CTV) with the dose-shift approximation, in stereotactic body radiation therapy (SBRT) of lung tumors considering setup errors and breathing motion. The dose-shift method was compared with a beam-shift method with dose recalculation. Included were 10 patients (10 tumors) selected to represent a variety of SBRT-treated lung tumors in terms of tumor location, CTV volume, and tumor density. An in-house developed toolkit within a treatment planning system allowed the shift of either the dose matrix or a shift of the beam isocenter with dose recalculation, to simulate setup errors and breathing motion. Setup shifts of different magnitudes (up to 10 mm) and directions as well as breathing with different peak-to-peak amplitudes (up to 10:5:5 mm) were modeled. The resulting dose-volume histograms (DVHs) were recorded and dose statistics were extracted. Generally, both the dose-shift and beam-shift methods resulted in calculated doses lower than the static planned dose, although the minimum (D 98% ) dose exceeded the prescribed dose in all cases, for setup shifts up to 5 mm. The dose-shift method also generally underestimated the dose compared with the beam-shift method. For clinically realistic systematic displacements of less than 5 mm, the results demonstrated that in the minimum dose region within the CTV, the dose-shift method was accurate to 2% (root-mean-square error). Breathing motion only marginally degraded the dose distributions. Averaged over the patients and shift directions, the dose-shift approximation was determined to be accurate to approximately 2% (RMS) within the CTV, for clinically relevant geometrical uncertainties for SBRT of lung tumors.

U S Navy Diving Manual. Volume 2. Mixed-Gas Diving. Revision 1.

DTIC Science & Technology

1981-07-01

has been soaked in a solution of portant aspects of underwater physics and physiology caustic potash. This chemical absorbed the carbon as they...between the diver’s breathing passages and the circuit must be of minimum volume minimum of caustic fumes. Water produced by the to preclude deadspace and...strongly react with water to pro- space around the absorbent bed to reduce the gas duce caustic fumes and cannot be used in UBA’s. flow distance. The

77 FR 72250 - Airworthiness Directives; Cessna Aircraft Company Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-05

... rubbing against the right steering tube assembly during rudder pedal actuation. This proposed AD would require you to install the forward and aft fuel return line support clamps and brackets; inspect for a minimum clearance between the fuel return line assembly and the steering tube assembly and clearance...

Delineating the Ambulatory Care Nursing Activities in the Navy Medical Department. Phase 1. Workload Management System for Nursing Ambulatory Care Project

DTIC Science & Technology

1987-04-01

24 Nasal gastric tube insertion 23 54 ABGs 22 Physical examination 21 Spirometry 20 Occupational health assessment 20 Obtain legal blood/urine samples...restraint Apply wrist/ankle restraint : - Cough and deep breatheC :3 EXtubatton t: :2 Place infant on papoose board :: :2 Incentive spirom•eter t

Drawing of the Buddy Secondary Life Support System

NASA Image and Video Library

1970-12-22

S70-56965 (December 1970) --- Drawing of the newly developed Buddy Secondary Life Support System (BSLSS). The life-sustaining system will be provided for the first time on the Apollo 14 lunar landing mission. The two flexible hoses, to be used on the second Apollo 14 extravehicular activity (EVA), will be among the paraphernalia on the Modular Equipment Transporter (MET) or two-wheeled workshop, and readily accessible in an emergency. During EVAs the Portable Life Support System (PLSS) supplies the astronaut with breathing and suit-pressurizing oxygen and water flow for the liquid-cooling garment -- a suit of knitted long underwear with thin tubing woven in the torso and limbs. The tubes carry water from a reservoir in the PLSS, and the circulating water serves to carry the astronaut's metabolic heat to a heat exchanger in the PLSS. Before the BSLSS was devised, the emergency tank was required to furnish not only suit pressure and breathing oxygen, but also cooling through a high oxygen flow rate. The BSLSS, by sharing the water supply between the two crewmen, stretches the time of the emergency oxygen from about 40 minutes to 60 to 75 minutes.

Deodorization of Garlic Breath by Foods, and the Role of Polyphenol Oxidase and Phenolic Compounds.

PubMed

Mirondo, Rita; Barringer, Sheryl

2016-10-01

Garlic causes a strong garlic breath that may persist for almost a day. Therefore, it is important to study deodorization techniques for garlic breath. The volatiles responsible for garlic breath include diallyl disulfide, allyl mercaptan, allyl methyl disulfide, and allyl methyl sulfide. After eating garlic, water (control), raw, juiced or heated apple, raw or heated lettuce, raw or juiced mint leaves, or green tea were consumed immediately. The levels of the garlic volatiles on the breath were analyzed from 1 to 60 min by selected ion flow tube mass spectrometry (SIFT-MS). Garlic was also blended with water (control), polyphenol oxidase (PPO), rosemarinic acid, quercetin or catechin, and the volatiles in the headspace analyzed from 3 to 40 min by SIFT-MS. Raw apple, raw lettuce, and mint leaves significantly decreased all of the garlic breath volatiles in vivo. The proposed mechanism is enzymatic deodorization where volatiles react with phenolic compounds. Apple juice and mint juice also had a deodorizing effect on most of the garlic volatiles but were generally not as effective as the raw food, probably because the juice had enzymatic activity but the phenolic compounds had already polymerized. Both heated apple and heated lettuce produced a significant reduction of diallyl disulfide and allyl mercaptan. The presence of phenolic compounds that react with the volatile compounds even in the absence of enzymes is the most likely mechanism. Green tea had no deodorizing effect on the garlic volatile compounds. Rosmarinic acid, catechin, quercetin, and PPO significantly decreased all garlic breath volatiles in vitro. Rosmarinic acid was the most effective at deodorization. © 2016 Institute of Food Technologists®.

Bilateral Pneumothoraces in a Trauma Patient After Dobhoff Tube Insertion

PubMed Central

Abidali, Ali; Mangram, Alicia; Shirah, Gina R.; Wilson, Whitney; Abidali, Ahmed; Moeser, Phillip; Dzandu, James K.

2018-01-01

Patient: Male, 74 Final Diagnosis: Pneumothorax Symptoms: Hypoxemia • shortness of breath Medication: — Clinical Procedure: — Specialty: Surgery Objective: Diagnostic/therapeutic accidents Background: Dobhoff tube insertion is a common procedure used in the clinical setting to deliver enteral nutrition. Although it is often viewed as an innocuous bedside procedure, there are risks for numerous complications such as tracheobronchial insertion, which could lead to deleterious consequences. We present to our knowledge the first reported case of bilateral pneumothoraces caused by the insertion of a Dobhoff tube. In addition, we also discuss common pitfalls for confirming the positioning of Dobhoff tubes, as well as risk factors that can predispose a patient to improper tube placement. Case Report: We present the case of a 74-year-old male patient with multiple orthopedic injuries following an auto-pedestrian collision. Five attempts were made to place a Dobhoff tube to maintain enteral nutrition. Follow-up abdominal x-ray revealed displacement of the Dobhoff tube in the left pleural space. After removal of the tube, a follow-up chest x-ray revealed iatrogenic bilateral pneumothoraces. Acute hypoxemic respiratory failure ensued; therefore, bilateral chest tubes were placed. Over the next three weeks, the patient’s respiratory status improved and both chest tubes were removed. The patient was eventually discharged to a skilled nursing facility. Conclusions: Improper placement of Dobhoff tubes can lead to rare complications such as bilateral pneumothoraces. This unique case report of bilateral pneumothoraces after Dobhoff tube placement emphasizes the necessity of using proper diagnostic techniques for verifying proper tube placement, as well as understanding the risk factors that predispose a patient to a malpositioned tube. PMID:29503437

[Heated humidification during CPAP with and without tube insulation].

PubMed

Rühle, K-H; Domanski, U; Schröder, M; Franke, K J; Nilius, G

2010-05-01

Patients with obstructive sleep apnoea syndrome (OSAS) under continuous positive pressure (CPAP) often complain about drying-up of the throat and nasal mucosa. In many cases the problem can be eliminated with a heated humidifier (WLB). Especially in a cold environment condensation forming on cooling of the air in the tube and the mask can be observed. To avoid this, some patients use an insulating tube covering. We investigated the effect of temperature (T) and relative humidity (rH) of the environment, the ventilation pressure, mask leaks, insulation of tubing on the T and rH% of the delivered air at the end of the tube or in the mask in OSAS patients. All measurements were performed with a conventional WLB (S8, Resmed Fa) and a temperature and humidity sensor (Fa Testo, Lenzkirch). 8 patients with OSAS were examined during the day at a room temperature of 16.4 degrees C. The temperature at the outlet of the WLB increased with a higher ambient temperature. Through isolation with a hose cover the temperature drop in the tube was reduced by 2.3 degrees C. By tube insulation a mean increase in temperature between 1.6 and 1.0 C during normal breathing in dependence on the leakage flow in the mask was found. Due to additional insulation with a tube cover the mask temperature can be increased, albeit slightly, and the formation of condensation is reduced.

Ignition Study on a Rotary-valved Air-breathing Pulse Detonation Engine

NASA Astrophysics Data System (ADS)

Wu, Yuwen; Han, Qixiang; Shen, Yujia; Zhao, Wei

2017-05-01

In the present study, the ignition effect on detonation initiation was investigated in the air-breathing pulse detonation engine. Two kinds of fuel injection and ignition methods were applied. For one method, fuel and air was pre-mixed outside the PDE and then injected into the detonation tube. The droplet sizes of mixtures were measured. An annular cavity was used as the ignition section. For the other method, fuel-air mixtures were mixed inside the PDE, and a pre-combustor was utilized as the ignition source. At firing frequency of 20 Hz, transition to detonation was obtained. Experimental results indicated that the ignition position and initial flame acceleration had important effects on the deflagration-to-detonation transition.

Structure of sunspot penumbrae - Fallen magnetic flux tubes

NASA Technical Reports Server (NTRS)

Wentzel, Donat G.

1992-01-01

A model is presented of a sunspot penumbra involving magnetic flux tubes that have fallen into the photosphere and float there. An upwelling at the inner end of a fallen tube continuously provides additional gas. This gas flows along and lengthens the tube and is observable as the Evershed flow. Fallen flux tubes may appear as bright streaks near the upwelling, but they become dark filaments further out. The model is corroborated by recent optical high-resolution magnetic data regarding the penumbral filaments, by the 12-micron magnetic measurements relevant to the height of the temperature minimum, and by photographs of the umbra/penumbra boundary.

Dependence of exhaled breath composition on exogenous factors, smoking habits and exposure to air pollutants*

PubMed Central

Mochalski, P; Filipiak, A; Bajtarevic, A; Ager, C; Denz, H; Hilbe, W; Jamnig, H; Hackl, M; Dzien, A; Amann, A

2013-01-01

Non-invasive disease monitoring on the basis of volatile breath markers is a very attractive but challenging task. Several hundreds of compounds have been detected in exhaled air using modern analytical techniques (e.g. proton-transfer reaction mass spectrometry, gas chromatography-mass spectrometry) and have even been linked to various diseases. However, the biochemical background for most of compounds detected in breath samples has not been elucidated; therefore, the obtained results should be interpreted with care to avoid false correlations. The major aim of this study was to assess the effects of smoking on the composition of exhaled breath. Additionally, the potential origin of breath volatile organic compounds (VOCs) is discussed focusing on diet, environmental exposure and biological pathways based on other’s studies. Profiles of VOCs detected in exhaled breath and inspired air samples of 115 subjects with addition of urine headspace derived from 50 volunteers are presented. Samples were analyzed with GC-MS after preconcentration on multibed sorption tubes in case of breath samples and solid phase micro-extraction (SPME) in the case of urine samples. Altogether 266 compounds were found in exhaled breath of at least 10% of the volunteers. From these, 162 compounds were identified by spectral library match and retention time (based on reference standards). It is shown that the composition of exhaled breath is considerably influenced by exposure to pollution and indoor-air contaminants and particularly by smoking. More than 80 organic compounds were found to be significantly related to smoking, the largest group comprising unsaturated hydrocarbons (29 dienes, 27 alkenes and 3 alkynes). On the basis of the presented results, we suggest that for the future understanding of breath data it will be necessary to carefully investigate the potential biological origin of volatiles, e.g., by means of analysis of tissues, isolated cell lines or other body fluids. In particular, VOCs linked to smoking habit or being the results of human exposure should be considered with care for clinical diagnosis since small changes in their concentration profiles (typically in the pptv–ppbv range) revealing that the outbreak of certain disease might be hampered by already high background. PMID:22932429

Cuff depth and continuous chest auscultation method for determination of tracheal tube insertion depth in nasal intubation: observational study.

PubMed

Ouchi, Kentaro; Sugiyama, Kazuna

2016-04-01

Incorrect endobronchial placement of the tracheal tube can lead to serious complications. Hence, it is necessary to determine the accuracy of tracheal tube positioning. Markers are included on tracheal tubes, in the process of their manufacture, as indicators of approximate intubation depth. In addition, continuous chest auscultation has been used for determining the proper position of the tube. We examined insertion depth using the cuff depth and continuous chest auscultation method (CC method), compared with insertion depth determined by the marker method, to assess the accuracy of these methods. After induction of anesthesia, tracheal intubation was performed in each patient. In the CC method, the depth of tube insertion was measured when the cuff had passed through the glottis, and again when breath sounds changed in quality; the depth of tube insertion was determined from these values. In the marker method, the depth of tube insertion was measured and determined when the marker of the tube had reached the glottis, using insertion depth according to the marker as an index. Insertion depth by the marker method was 26.6 ± 1.2 cm and by the CC method was 28.0 ± 1.2 cm (P < 0.0001). The CC method indicated a significantly greater depth than the marker method. This study determined the safe range of tracheal tube placement. Tube positions determined by the CC method were about 1 cm deeper than those determined by the marker. This information is important to prevent accidental one-lung ventilation and accidental extubation. UMIN No. UMIN000011375.

Analysis of Exhaled Breath Volatile Organic Compounds in Inflammatory Bowel Disease: A Pilot Study.

PubMed

Hicks, Lucy C; Huang, Juzheng; Kumar, Sacheen; Powles, Sam T; Orchard, Timothy R; Hanna, George B; Williams, Horace R T

2015-09-01

Distinguishing between the inflammatory bowel diseases [IBD], Crohn's disease [CD] and ulcerative colitis [UC], is important for determining management and prognosis. Selected ion flow tube mass spectrometry [SIFT-MS] may be used to analyse volatile organic compounds [VOCs] in exhaled breath: these may be altered in disease states, and distinguishing breath VOC profiles can be identified. The aim of this pilot study was to identify, quantify, and analyse VOCs present in the breath of IBD patients and controls, potentially providing insights into disease pathogenesis and complementing current diagnostic algorithms. SIFT-MS breath profiling of 56 individuals [20 UC, 18 CD, and 18 healthy controls] was undertaken. Multivariate analysis included principal components analysis and partial least squares discriminant analysis with orthogonal signal correction [OSC-PLS-DA]. Receiver operating characteristic [ROC] analysis was performed for each comparative analysis using statistically significant VOCs. OSC-PLS-DA modelling was able to distinguish both CD and UC from healthy controls and from one other with good sensitivity and specificity. ROC analysis using combinations of statistically significant VOCs [dimethyl sulphide, hydrogen sulphide, hydrogen cyanide, ammonia, butanal, and nonanal] gave integrated areas under the curve of 0.86 [CD vs healthy controls], 0.74 [UC vs healthy controls], and 0.83 [CD vs UC]. Exhaled breath VOC profiling was able to distinguish IBD patients from controls, as well as to separate UC from CD, using both multivariate and univariate statistical techniques. Copyright © 2015 European Crohn’s and Colitis Organisation (ECCO). Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com.

A prospective gating method to acquire a diverse set of free-breathing CT images for model-based 4DCT

NASA Astrophysics Data System (ADS)

O'Connell, D.; Ruan, D.; Thomas, D. H.; Dou, T. H.; Lewis, J. H.; Santhanam, A.; Lee, P.; Low, D. A.

2018-02-01

Breathing motion modeling requires observation of tissues at sufficiently distinct respiratory states for proper 4D characterization. This work proposes a method to improve sampling of the breathing cycle with limited imaging dose. We designed and tested a prospective free-breathing acquisition protocol with a simulation using datasets from five patients imaged with a model-based 4DCT technique. Each dataset contained 25 free-breathing fast helical CT scans with simultaneous breathing surrogate measurements. Tissue displacements were measured using deformable image registration. A correspondence model related tissue displacement to the surrogate. Model residual was computed by comparing predicted displacements to image registration results. To determine a stopping criteria for the prospective protocol, i.e. when the breathing cycle had been sufficiently sampled, subsets of N scans where 5  ⩽  N  ⩽  9 were used to fit reduced models for each patient. A previously published metric was employed to describe the phase coverage, or ‘spread’, of the respiratory trajectories of each subset. Minimum phase coverage necessary to achieve mean model residual within 0.5 mm of the full 25-scan model was determined and used as the stopping criteria. Using the patient breathing traces, a prospective acquisition protocol was simulated. In all patients, phase coverage greater than the threshold necessary for model accuracy within 0.5 mm of the 25 scan model was achieved in six or fewer scans. The prospectively selected respiratory trajectories ranked in the (97.5  ±  4.2)th percentile among subsets of the originally sampled scans on average. Simulation results suggest that the proposed prospective method provides an effective means to sample the breathing cycle with limited free-breathing scans. One application of the method is to reduce the imaging dose of a previously published model-based 4DCT protocol to 25% of its original value while achieving mean model residual within 0.5 mm.

42 CFR 84.122 - Breathing resistance test; minimum requirements.

Code of Federal Regulations, 2012 CFR

2012-10-01

... Exhalation Front-mounted or back-mounted (without particulate filter) 60 75 20 Front-mounted or back-mounted (with approved particulate filter) 70 85 20 Chin-style (without particulate filter) 40 55 20 Chin-style (with approved particulate filter) 65 80 20 Escape (without particulate filter) 60 75 20 Escape (with...

42 CFR 84.122 - Breathing resistance test; minimum requirements.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Exhalation Front-mounted or back-mounted (without particulate filter) 60 75 20 Front-mounted or back-mounted (with approved particulate filter) 70 85 20 Chin-style (without particulate filter) 40 55 20 Chin-style (with approved particulate filter) 65 80 20 Escape (without particulate filter) 60 75 20 Escape (with...

42 CFR 84.122 - Breathing resistance test; minimum requirements.

Code of Federal Regulations, 2013 CFR

2013-10-01

... Exhalation Front-mounted or back-mounted (without particulate filter) 60 75 20 Front-mounted or back-mounted (with approved particulate filter) 70 85 20 Chin-style (without particulate filter) 40 55 20 Chin-style (with approved particulate filter) 65 80 20 Escape (without particulate filter) 60 75 20 Escape (with...

42 CFR 84.122 - Breathing resistance test; minimum requirements.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Exhalation Front-mounted or back-mounted (without particulate filter) 60 75 20 Front-mounted or back-mounted (with approved particulate filter) 70 85 20 Chin-style (without particulate filter) 40 55 20 Chin-style (with approved particulate filter) 65 80 20 Escape (without particulate filter) 60 75 20 Escape (with...

42 CFR 84.122 - Breathing resistance test; minimum requirements.

Code of Federal Regulations, 2014 CFR

2014-10-01

... Exhalation Front-mounted or back-mounted (without particulate filter) 60 75 20 Front-mounted or back-mounted (with approved particulate filter) 70 85 20 Chin-style (without particulate filter) 40 55 20 Chin-style (with approved particulate filter) 65 80 20 Escape (without particulate filter) 60 75 20 Escape (with...

High Power Microwave Tube Reliability Study

DTIC Science & Technology

1976-08-01

Factors . . . . . ................ 67 1. Environmental Factors . . . . . . . . . a. Ground Fixed ...... .......... 67 b. Ground Mobile ...including cube structure and operating parameters as factors in the models but also environment and aplication . Initially, the tubes to be included in...instLllations. Mobile ground based and seagoing systems have minimum restrictions, spacecraft systems the maximum and airborne system Y 6 .*.. restrictionts

Gluon correlations from a glasma flux-tube model compared to measured hadron correlations on transverse momentum (p t,p t) and angular differences (η Δ,φ Δ)

DOE PAGES

Trainor, Thomas A.; Ray, R. L.

2011-09-09

A glasma flux-tube model has been proposed to explain strong elongation on pseudorapidity η of the same-side two-dimensional (2D) peak in minimum-bias angular correlations from √( sNN)=200 GeV Au-Au collisions. The same-side peak or “soft ridge” is said to arise from coupling of flux tubes to radial flow whereby gluons radiated transversely from flux tubes are boosted by radial flow to form a narrow structure or ridge on azimuth. In this study we test the theory conjecture by comparing measurements to predictions for particle production, spectra, and correlations from the glasma model and from conventional fragmentation processes. We conclude thatmore » the glasma model is contradicted by measured hadron yields, spectra, and correlations, whereas a two-component model of hadron production, including minimum-bias parton fragmentation, provides a quantitative description of most features of the data, although η elongation of the same-side 2D peak remains undescribed.« less

All APAPs Are Not Equivalent for the Treatment of Sleep Disordered Breathing: A Bench Evaluation of Eleven Commercially Available Devices

PubMed Central

Zhu, Kaixian; Roisman, Gabriel; Aouf, Sami; Escourrou, Pierre

2015-01-01

Study Objectives: This study challenged on a bench-test the efficacy of auto-titrating positive airway pressure (APAP) devices for obstructive sleep disordered breathing treatment and evaluated the accuracy of the device reports. Methods: Our bench consisted of an active lung simulator and a Starling resistor. Eleven commercially available APAP devices were evaluated on their reactions to single-type SDB sequences (obstructive apnea and hypopnea, central apnea, and snoring), and to a long general breathing scenario (5.75 h) simulating various SDB during four sleep cycles and to a short scenario (95 min) simulating one sleep cycle. Results: In the single-type sequence of 30-minute repetitive obstructive apneas, only 5 devices normalized the airflow (> 70% of baseline breathing amplitude). Similarly, normalized breathing was recorded with 8 devices only for a 20-min obstructive hypopnea sequence. Five devices increased the pressure in response to snoring. Only 4 devices maintained a constant minimum pressure when subjected to repeated central apneas with an open upper airway. In the long general breathing scenario, the pressure responses and the treatment efficacy differed among devices: only 5 devices obtained a residual obstructive AHI < 5/h. During the short general breathing scenario, only 2 devices reached the same treatment efficacy (p < 0.001), and 3 devices underestimated the AHI by > 10% (p < 0.001). The long scenario led to more consistent device reports. Conclusion: Large differences between APAP devices in the treatment efficacy and the accuracy of report were evidenced in the current study. Citation: Zhu K, Roisman G, Aouf S, Escourrou P. All APAPs are not equivalent for the treatment of sleep disordered breathing: a bench evaluation of eleven commercially available devices. J Clin Sleep Med 2015;11(7):725–734. PMID:25766708

Numerical heat transfer analysis of transcritical hydrocarbon fuel flow in a tube partially filled with porous media

NASA Astrophysics Data System (ADS)

Jiang, Yuguang; Feng, Yu; Zhang, Silong; Qin, Jiang; Bao, Wen

2016-01-01

Hydrocarbon fuel has been widely used in air-breathing scramjets and liquid rocket engines as coolant and propellant. However, possible heat transfer deterioration and threats from local high heat flux area in scramjet make heat transfer enhancement essential. In this work, 2-D steady numerical simulation was carried out to study different schemes of heat transfer enhancement based on a partially filled porous media in a tube. Both boundary and central layouts were analyzed and effects of gradient porous media were also compared. The results show that heat transfer in the transcritical area is enhanced at least 3 times with the current configuration compared to the clear tube. Besides, the proper use of gradient porous media also enhances the heat transfer compared to homogenous porous media, which could help to avoid possible over-temperature in the thermal protection.

Tension bulla: a cause of reversible pulmonary hypertension.

PubMed

Waxman, Michael J; Waxman, Jacob D; Forman, John M

2015-01-01

A tension pneumothorax represents a medical emergency warranting urgent diagnosis and treatment. A rapidly expanding bulla may resemble the same clinical presentation but requires an entirely different treatment. A 53-year-old woman presented with increasing shortness of breath and her physical examination and chest x-ray were interpreted as showing a tension pneumothorax. A chest tube was placed which did not resolve the process. Placement of a second chest tube was likewise unsuccessful. A chest CT was then performed and was interpreted as showing an unresolved tension pneumothorax, despite seemingly adequate placement of the 2 chest tubes. Further review of the CT showed the border of a giant bulla and a tentative diagnosis was made of a rapidly expanding bulla with tension physiology. Echocardiogram revealed significant pulmonary hypertension. The bulla was surgically excised, the patient had marked improvement in her clinical symptoms and signs, and echocardiographic follow-up showed complete resolution of the pulmonary hypertension.

Improved Calibration Of Acoustic Plethysmographic Sensors

NASA Technical Reports Server (NTRS)

Zuckerwar, Allan J.; Davis, David C.

1993-01-01

Improved method of calibration of acoustic plethysmographic sensors involves acoustic-impedance test conditions like those encountered in use. Clamped aluminum tube holds source of sound (hydrophone) inside balloon. Test and reference sensors attached to outside of balloon. Sensors used to measure blood flow, blood pressure, heart rate, breathing sounds, and other vital signs from surfaces of human bodies. Attached to torsos or limbs by straps or adhesives.

An adult case of giant bronchogenic cyst mimicking tension pneumothorax.

PubMed

Yalcinkaya, Serhat; Vural, A Hakan; Ozal, Hasan

2010-10-01

Bronchogenic cysts are usually discovered only incidentally in the adult. A giant bronchogenic cyst in a 19-year-old woman presenting with pain and shortness of breath was mistaken for tension pneumothorax and initially treated with tube thoracostomy. Giant bullae were diagnosed by computed tomography. Bullae resection was undertaken, but the remaining lung tissue required pneumonectomy. Pathologic examination of the specimen confirmed bronchogenic cyst.

Daily nursing care on patients undergoing venous-venous extracorporeal membrane oxygenation: a challenging procedure!

PubMed

Redaelli, Sara; Zanella, Alberto; Milan, Manuela; Isgrò, Stefano; Lucchini, Alberto; Pesenti, Antonio; Patroniti, Nicolò

2016-12-01

Daily nursing in critical care patients may alter vital parameters, especially in the most critically ill patients. The aim of our study was to evaluate feasibility and safety of daily nursing on patients undergoing venous-venous extracorporeal membrane oxygenation (vv-ECMO) for severe respiratory failure. Daily nursing was performed following defined phases (sponge bath, elevation with scooping stretcher, change position of endotracheal tube, dressing replacement). We recorded physiological and ECMO parameters before and during daily nursing in 5 patients for several days (total: 25 daily nursing) and adverse events: desaturation, hypertension, reduction of mixed venous oxygen saturation, arterial oxygen saturation or ECMO blood flow and elevation in minute ventilation. Sedative drug dosage and additional bolus were recorded. Daily nursing was performed in 92 % of cases (23/25), with a minimum of two adverse events per daily nursing. Hypertension and tachycardia were mostly recorded at the beginning, while desaturation, reduction in mixed venous oxygen saturation and blood flow were recorded during elevation with scooping stretcher. Increase in minute ventilation was frequent in spontaneous breathing patients. Additional bolus of sedation was required before and/or during nursing. Daily nursing significantly alters physiologic parameters; thus, it should be performed only when physicians are readily available to treat adverse events.

Variation of the pressure limits of flame propagation with tube diameter for propane-air mixtures

NASA Technical Reports Server (NTRS)

Belles, Frank E; Simon, Dorothy M

1951-01-01

An investigation was made of the variation of the pressure limits of flame propagation with tube diameter for quiescent propane with tube diameter for quiescent propane-air mixtures. Pressure limits were measured in glass tubes of six different inside diameters, with a precise apparatus. Critical diameters for flame propagation were calculated and the effect of pressure was determined. The critical diameters depended on the pressure to the -0.97 power for stoichiometric mixtures. The pressure dependence decreased with decreasing propane concentration. Critical diameters were related to quenching distance, flame speeds, and minimum ignition energy.

All APAPs Are Not Equivalent for the Treatment of Sleep Disordered Breathing: A Bench Evaluation of Eleven Commercially Available Devices.

PubMed

Zhu, Kaixian; Roisman, Gabriel; Aouf, Sami; Escourrou, Pierre

2015-07-15

This study challenged on a bench-test the efficacy of auto-titrating positive airway pressure (APAP) devices for obstructive sleep disordered breathing treatment and evaluated the accuracy of the device reports. Our bench consisted of an active lung simulator and a Starling resistor. Eleven commercially available APAP devices were evaluated on their reactions to single-type SDB sequences (obstructive apnea and hypopnea, central apnea, and snoring), and to a long general breathing scenario (5.75 h) simulating various SDB during four sleep cycles and to a short scenario (95 min) simulating one sleep cycle. In the single-type sequence of 30-minute repetitive obstructive apneas, only 5 devices normalized the airflow (> 70% of baseline breathing amplitude). Similarly, normalized breathing was recorded with 8 devices only for a 20-min obstructive hypopnea sequence. Five devices increased the pressure in response to snoring. Only 4 devices maintained a constant minimum pressure when subjected to repeated central apneas with an open upper airway. In the long general breathing scenario, the pressure responses and the treatment efficacy differed among devices: only 5 devices obtained a residual obstructive AHI < 5/h. During the short general breathing scenario, only 2 devices reached the same treatment efficacy (p < 0.001), and 3 devices underestimated the AHI by > 10% (p < 0.001). The long scenario led to more consistent device reports. Large differences between APAP devices in the treatment efficacy and the accuracy of report were evidenced in the current study. © 2015 American Academy of Sleep Medicine.

The Humidity in a Low-Flow Dräger Fabius Anesthesia Workstation with or without Thermal Insulation or a Heat and Moisture Exchanger: A Prospective Randomized Clinical Trial.

PubMed

de Oliveira, Sergius A R; Lucio, Lorena M C; Modolo, Norma S P; Hayashi, Yoko; Braz, Mariana G; de Carvalho, Lídia R; Braz, Leandro G; Braz, José Reinaldo C

2017-01-01

During anesthesia, as compared with intensive care, the time of the tracheal intubation is much shorter. An inhaled gas minimum humidity of 20 mgH2O.L-1 is recommended to reduce the deleterious effects of dry gas on the airways during anesthesia with tracheal intubation. The Fabius GS Premium® anesthesia workstation (Dräger Medical, Lübeck, Germany) has a built-in hotplate to heat gases in the breathing circuit. A heat and moisture exchanger (HME) is used to further heat and humidify the inhaled gas. The humidity of the gases in the breathing circuit is influenced by the ambient temperature. We compared the humidity of the inhaled gases from a low-flow Fabius anesthesia workstation with or without thermal insulation (TI) of the breathing circuit and with or without an HME. We conducted a prospective randomized trial in 41 adult female patients who underwent elective abdominal surgery. The patients were allocated into four groups according to the devices used to ventilate their lungs using a Dräger Fabius anesthesia workstation with a low gas flow (1 L.min-1): control, with TI, with an HME or with TI and an HME (TIHME). The mean temperature and humidity of the inhaled gases were measured during 2-h after connecting the patients to the breathing circuit. The mean inhaled gas temperature and absolute humidity were higher in the HME (29.2±1.3°C; 28.1±2.3 mgH2O·L-1) and TIHME (30.1±1.2°C; 29.4±2.0 mgH2O·L-1) groups compared with the control (27.5±1.0°C; 25.0±1.8 mgH2O·L-1) and TI (27.2±1.1°C; 24.9±1.8 mgH2O·L-1) groups (P = 0.003 and P<0.001, respectively). The low-flow Fabius GS Premium breathing circuit provides the minimum humidity level of inhaled gases to avoid damage to the tracheobronchial epithelia during anesthesia. TI of the breathing circuit does not increase the humidity of the inhaled gases, whereas inserting an HME increases the moisture of the inhaled gases closer to physiological values.

Simple and fast orotracheal intubation procedure in rats.

PubMed

Tomasello, Giovanni; Damiani, Francesco; Cassata, Giovanni; Palumbo, Vincenzo Davide; Sinagra, Emanuele; Damiani, Provvidenza; Bruno, Antonino; Cicero, Luca; Cupido, Francesco; Carini, Francesco; Lo Monte, Attilio Ignazio

2016-05-06

Endotracheal intubation in the rat is difficult because of the extremely small size of anatomical structures (oral cavity, epiglottis and vocal cords), small inlet for an endotracheal tube and the lack of proper technical instruments. In this study we used seventy rats weighting 400-500 g. The equipment needed for the intubation was an operating table, a longish of cotton, a cotton tip, orotracheal tube, neonatal laryngoscope blades, KTR4 small animal ventilator and isoflurane for inhalation anaesthesia. Premedication was carried out by medetomidine hydrochloride 1 mg/mL; then, thanks to a closed glass chamber, a mixture of oxygen and isoflurane was administered. By means of a neonatal laryngoscope the orotracheal tube was advanced into the oral cavity until the wire guide was visualized trough the vocal cords; then it was passed through them. The tube was introduced directly into the larynx over the wire guide; successively, the guide was removed and the tube placed into the trachea. Breathing was confirmed using a glove, cut at the end of a finger, simulating a small balloon. We achieved a fast and simple orotracheal intubation in all animals employed. We believe that our procedure is easier and faster than those previously reported in scientific literature.

Optimal Area Profiles for Ideal Single Nozzle Air-Breathing Pulse Detonation Engines

NASA Technical Reports Server (NTRS)

Paxson, Daniel E.

2003-01-01

The effects of cross-sectional area variation on idealized Pulse Detonation Engine performance are examined numerically. A quasi-one-dimensional, reacting, numerical code is used as the kernel of an algorithm that iteratively determines the correct sequencing of inlet air, inlet fuel, detonation initiation, and cycle time to achieve a limit cycle with specified fuel fraction, and volumetric purge fraction. The algorithm is exercised on a tube with a cross sectional area profile containing two degrees of freedom: overall exit-to-inlet area ratio, and the distance along the tube at which continuous transition from inlet to exit area begins. These two parameters are varied over three flight conditions (defined by inlet total temperature, inlet total pressure and ambient static pressure) and the performance is compared to a straight tube. It is shown that compared to straight tubes, increases of 20 to 35 percent in specific impulse and specific thrust are obtained with tubes of relatively modest area change. The iterative algorithm is described, and its limitations are noted and discussed. Optimized results are presented showing performance measurements, wave diagrams, and area profiles. Suggestions for future investigation are also discussed.

Chest tube stripping in pediatric oncology patients: an experimental study.

PubMed

Oakes, L L; Hinds, P; Rao, B; Bozeman, P; Taylor, B; Stokes, D; Fairclough, D

1993-07-01

Stripping of chest tubes to promote drainage of the thorax of postthoracotomy patients has been routine practice, based on tradition. Recent published findings indicate that significant negative pressures are generated in the tube during stripping that could cause pain, bleeding and possible damage to the patient's lung tissue. To determine whether pediatric oncology patients whose chest tubes were not stripped would differ in frequency of pain, fever or lung complications from patients who underwent routine tube stripping. Data were collected at multiple points during the first 72-hour postoperative period from 16 patients assigned to the stripped or unstripped groups. Pain was measured by the Faces Pain Scale and the Visual Analogue Scale; temperature, by electronic thermometer; and lung complications, by stethoscope and radiographs. Both groups, which were comparable for age, primary diagnosis and prior history of lung problems, received identical supportive nursing and medical care, with the physicians blind to group assignment. The two groups did not differ significantly in frequency of pain, incidence of fever, breath sounds or radiographic findings across measurement points. A strong correlation was found between the pain scores using the two instruments. Patients whose tubes were not stripped did not have an increased risk of infection or lung complications. Study findings indicated that stripping did not increase the frequency of pain. Stripping of chest tubes as a routine postoperative measure is questioned.

Analysis of a deflating soap bubble

NASA Astrophysics Data System (ADS)

Jackson, David P.; Sleyman, Sarah

2010-10-01

A soap bubble on the end of a cylindrical tube is seen to deflate as the higher pressure air inside the bubble escapes through a tube. We perform an experiment to measure the radius of the slowly deflating bubble and observe that the radius decreases to a minimum before quickly increasing. This behavior reflects the fact that the bubble ends up as a flat surface over the end of the tube. A theoretical analysis reproduces this behavior and compares favorably with the experimental data.

Investigation of Sustained Detonation Devices: the Pulse Detonation Engine-Crossover System and the Rotating Detonation Engine System

NASA Astrophysics Data System (ADS)

Driscoll, Robert B.

An experimental study is conducted on a Pulse Detonation Engine-Crossover System to investigate the feasibility of repeated, shock-initiated combustion and characterize the initiation performance. A PDE-crossover system can decrease deflagration-to-detonation transition length while employing a single spark source to initiate a multi-PDE system. Visualization of a transferred shock wave propagating through a clear channel reveals a complex shock train behind the leading shock. Shock wave Mach number and decay rate remains constant for varying crossover tube geometries and operational frequencies. A temperature gradient forms within the crossover tube due to forward flow of high temperature ionized gas into the crossover tube from the driver PDE and backward flow of ionized gas into the crossover tube from the driven PDE, which can cause intermittent auto-ignition of the driver PDE. Initiation performance in the driven PDE is strongly dependent on initial driven PDE skin temperature in the shock wave reflection region. An array of detonation tubes connected with crossover tubes is developed using optimized parameters and successful operation utilizing shock-initiated combustion through shock wave reflection is achieved and sustained. Finally, an air-breathing, PDE-Crossover System is developed to characterize the feasibility of shock-initiated combustion within an air-breathing pulse detonation engine. The initiation effectiveness of shock-initiated combustion is compared to spark discharge and detonation injection through a pre-detonator. In all cases, shock-initiated combustion produces improved initiation performance over spark discharge and comparable detonation transition run-up lengths relative to pre-detonator initiation. A computational study characterizes the mixing processes and injection flow field within a rotating detonation engine. Injection parameters including reactant flow rate, reactant injection area, placement of the fuel injection, and fuel injection distribution are varied to assess the impact on mixing. Decreasing reactant injection areas improves fuel penetration into the cross-flowing air stream, enhances turbulent diffusion of the fuel within the annulus, and increases local equivalence ratio and fluid mixedness. Staggering fuel injection holes produces a decrease in mixing when compared to collinear fuel injection. Finally, emulating nozzle integration by increasing annulus back-pressure increases local equivalence ratio in the injection region due to increased convection residence time.

49 CFR Appendix G to Subchapter B... - Minimum Periodic Inspection Standards

Code of Federal Regulations, 2013 CFR

2013-10-01

... missing or in danger of falling away. d. Brake Hose. (1) Hose with any damage extending through the outer... braid reinforcement or color difference between cover and inner tube. Exposure of second color is cause... hoses improperly joined (such as a splice made by sliding the hose ends over a piece of tubing and...

49 CFR Appendix G to Subchapter B... - Minimum Periodic Inspection Standards

Code of Federal Regulations, 2014 CFR

2014-10-01

... missing or in danger of falling away. d. Brake Hose. (1) Hose with any damage extending through the outer... braid reinforcement or color difference between cover and inner tube. Exposure of second color is cause... hoses improperly joined (such as a splice made by sliding the hose ends over a piece of tubing and...

49 CFR Appendix G to Subchapter B... - Minimum Periodic Inspection Standards

Code of Federal Regulations, 2012 CFR

2012-10-01

... missing or in danger of falling away. d. Brake Hose. (1) Hose with any damage extending through the outer... braid reinforcement or color difference between cover and inner tube. Exposure of second color is cause... hoses improperly joined (such as a splice made by sliding the hose ends over a piece of tubing and...

Effects of ion channel noise on neural circuits: an application to the respiratory pattern generator to investigate breathing variability.

PubMed

Yu, Haitao; Dhingra, Rishi R; Dick, Thomas E; Galán, Roberto F

2017-01-01

Neural activity generally displays irregular firing patterns even in circuits with apparently regular outputs, such as motor pattern generators, in which the output frequency fluctuates randomly around a mean value. This "circuit noise" is inherited from the random firing of single neurons, which emerges from stochastic ion channel gating (channel noise), spontaneous neurotransmitter release, and its diffusion and binding to synaptic receptors. Here we demonstrate how to expand conductance-based network models that are originally deterministic to include realistic, physiological noise, focusing on stochastic ion channel gating. We illustrate this procedure with a well-established conductance-based model of the respiratory pattern generator, which allows us to investigate how channel noise affects neural dynamics at the circuit level and, in particular, to understand the relationship between the respiratory pattern and its breath-to-breath variability. We show that as the channel number increases, the duration of inspiration and expiration varies, and so does the coefficient of variation of the breath-to-breath interval, which attains a minimum when the mean duration of expiration slightly exceeds that of inspiration. For small channel numbers, the variability of the expiratory phase dominates over that of the inspiratory phase, and vice versa for large channel numbers. Among the four different cell types in the respiratory pattern generator, pacemaker cells exhibit the highest sensitivity to channel noise. The model shows that suppressing input from the pons leads to longer inspiratory phases, a reduction in breathing frequency, and larger breath-to-breath variability, whereas enhanced input from the raphe nucleus increases breathing frequency without changing its pattern. A major source of noise in neuronal circuits is the "flickering" of ion currents passing through the neurons' membranes (channel noise), which cannot be suppressed experimentally. Computational simulations are therefore the best way to investigate the effects of this physiological noise by manipulating its level at will. We investigate the role of noise in the respiratory pattern generator and show that endogenous, breath-to-breath variability is tightly linked to the respiratory pattern. Copyright © 2017 the American Physiological Society.

Proton-transfer reaction mass spectrometry (PTRMS) in combination with thermal desorption (TD) for sensitive off-line analysis of volatiles.

PubMed

Crespo, Elena; Devasena, Samudrala; Sikkens, Cor; Centeno, Raymund; Cristescu, Simona M; Harren, Frans J M

2012-04-30

When performing trace gas analysis, it is not always possible to bring the source of volatiles and the gas analyzer together. In these cases, volatile storage containers, such as thermal desorption (TD) tubes, can be used for off-line measurement. TD is routinely combined with gas chromatography/mass spectrometry (GC/MS), but so far not with proton-transfer reaction mass spectrometry (PTRMS), which has a faster response. A PTR-quadrupole-MS instrument and a PTR-ion-trap-MS instrument were separately coupled to a TD unit for off-line analysis of trace volatiles in air. Carbograph 1TD/Carbopack X sorbent tubes were filled with different concentrations of a trace gas mixture containing low molecular weight volatiles (32 g/mol up to 136 g/mol) and measured with the above-mentioned combinations. The carrier gas in the TD unit was changed from helium to nitrogen to be able to combine this instrument with the mass spectrometer. Good linearity and reproducibility with the amount of gas stored were obtained. The storage capacity over time (up to 14 days) showed larger variability (<11% for all compounds, except for acetone 27%). Several tubes were filled with breath of different persons, and the breath of a smoker showed increased levels of acetonitrile and benzene. The combination of the PTR ion-trap instrument with the TD unit was also investigated. Due to its higher sampling rate, the ion-trap system showed higher throughput capabilities than the quadrupole system. The combination of TD with PTRMS using both a quadrupole and an ion trap for off-line volatile analysis has been validated. TD tubes can be a robust and compact volatile storage method when the mass spectrometry and the sampling cannot be performed in the same place, for example in large screening studies. In addition, a higher measurement throughput than with GC/MS could be obtained. Copyright © 2012 John Wiley & Sons, Ltd.

29 CFR 1910.423 - Post-dive procedures.

Code of Federal Regulations, 2012 CFR

2012-07-01

... human occupancy; (ii) A built-in-breathing-system with a minimum of one mask per occupant; (iii) A two-way voice communication system between occupants and a dive team member at the dive location; (iv) A... location. (6) A dive team member shall be available at the dive location during and for at least one hour...

29 CFR 1910.423 - Post-dive procedures.

Code of Federal Regulations, 2013 CFR

2013-07-01

... human occupancy; (ii) A built-in-breathing-system with a minimum of one mask per occupant; (iii) A two-way voice communication system between occupants and a dive team member at the dive location; (iv) A... location. (6) A dive team member shall be available at the dive location during and for at least one hour...

29 CFR 1910.423 - Post-dive procedures.

Code of Federal Regulations, 2010 CFR

2010-07-01

... human occupancy; (ii) A built-in-breathing-system with a minimum of one mask per occupant; (iii) A two-way voice communication system between occupants and a dive team member at the dive location; (iv) A... location. (6) A dive team member shall be available at the dive location during and for at least one hour...

29 CFR 1910.423 - Post-dive procedures.

Code of Federal Regulations, 2014 CFR

2014-07-01

... human occupancy; (ii) A built-in-breathing-system with a minimum of one mask per occupant; (iii) A two-way voice communication system between occupants and a dive team member at the dive location; (iv) A... location. (6) A dive team member shall be available at the dive location during and for at least one hour...

29 CFR 1910.423 - Post-dive procedures.

Code of Federal Regulations, 2011 CFR

2011-07-01

... human occupancy; (ii) A built-in-breathing-system with a minimum of one mask per occupant; (iii) A two-way voice communication system between occupants and a dive team member at the dive location; (iv) A... location. (6) A dive team member shall be available at the dive location during and for at least one hour...

42 CFR Appendix - Tables to Subpart H of Part 84

Code of Federal Regulations, 2011 CFR

2011-10-01

... 42 Public Health 1 2011-10-01 2011-10-01 false Tables to Subpart H of Part 84 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Self-Contained Breathing Apparatus Gas tightness test; minimum requirements. Pt. 84,...

Pressure dependence of the radial mode frequency in carbon nanotubes

NASA Astrophysics Data System (ADS)

Venkateswaran, Uma; Masica, D.; Sumanasekara, G.; Eklund, P.

2003-03-01

Recently, an analytical expression for the radial breathing mode frequency, ω_R, was derived by considering the oscillations of a thin hollow cylinder.[1] Using this result and the experimental pressure-dependence of the elastic and lattice constants of graphite, we show that the pressure derivative of ωR depends inversely on the nanotube diameter, D. Since ωR also depends inversely on D, the above result implies that the logarithmic pressure derivative of ω_R, i.e., dlnω_R/dP should be independent of D. We have performed high-pressure Raman scattering experiments on HiPCO-SWNT bundles using different laser excitations, thereby probing the radial modes from different diameter tubes. These measurements show an increase in dlnω_R/dP with increasing D. This difference between the predictions and experiments suggests that the main contribution to ω_R's pressure dependence in SWNT bundles stems from the tube-tube interactions within the bundle and from pressure-induced distortions to the tube cross-section. [1] G.D. Mahan, Phys. Rev. B 65, 235402 (2002).

49 CFR 40.267 - What problems always cause an alcohol test to be cancelled?

Code of Federal Regulations, 2010 CFR

2010-10-01

... always cause an alcohol test to be cancelled? As an employer, a BAT, or an STT, you must cancel an alcohol test if any of the following problems occur. These are “fatal flaws.” You must inform the DER that... the case of a screening test conducted on a saliva ASD or a breath tube ASD: (1) The STT or BAT reads...

Evaluation of Contaminant-Promoted Ignition in Scuba Equipment and Breathing Gas Delivery Systems

NASA Technical Reports Server (NTRS)

Forsyth, Elliott T.; Durkin, Robert; Beeson, Harold D.

2000-01-01

As the underwater diving industry continues to use greater concentrations of oxygen in their scuba systems, ignition of contaminants in these systems becomes a greater concern. Breathing gas makeup and distribution systems typically combine pure oxygen with various diluents to supply high-pressure cylinders for scuba applications. The hazards associated with these applications of oxygen and NITROX (oxygen and nitrogen mixture) gases require an evaluation of inherent contaminant levels and their associated promoted-ignition thresholds in these environments. In this study, several scuba component assemblies were tested after one year of use at the NASA Johnson Space Center Neutral Buoyancy Lab. The components were rapidly impacted with 50% NITROX gas to demonstrate their ignition resistance, then disassembled to evaluate their cleanliness. A follow-up study was then performed on the ignition thresholds of hydrocarbon-bascd oil films in oxygen and NITROX environments in an attempt to define the cleaning requirements for these systems. Stainless steel tubes were contaminated and verified to known levels and placed in a pneumatic impact test system where they were rapidly pressurized with the test gas. Ignitions were determined using a photodiode connected to the end of the contaminated tube. The results of the scuba component tests, cleanliness evaluation, and contaminant ignition study are discussed and compared for 50% NITROX and 100% oxygen environments.

Tension pneumothorax secondary to automatic mechanical compression decompression device.

PubMed

Hutchings, A C; Darcy, K J; Cumberbatch, G L A

2009-02-01

The details are presented of the first published case of a tension pneumothorax induced by an automatic compression-decompression (ACD) device during cardiac arrest. An elderly patient collapsed with back pain and, on arrival of the crew, was in pulseless electrical activity (PEA) arrest. He was promptly intubated and correct placement of the endotracheal tube was confirmed by noting equal air entry bilaterally and the ACD device applied. On the way to the hospital he was noted to have absent breath sounds on the left without any change in the position of the endotracheal tube. Needle decompression of the left chest caused a hiss of air but the patient remained in PEA. Intercostal drain insertion in the emergency department released a large quantity of air from his left chest but without any change in his condition. Post-mortem examination revealed a ruptured abdominal aortic aneurysm as the cause of death. Multiple left rib fractures and a left lung laceration secondary to the use of the ACD device were also noted, although the pathologist felt that the tension pneumothorax had not contributed to the patient's death. It is recommended that a simple or tension pneumothorax should be considered when there is unilateral absence of breath sounds in addition to endobronchial intubation if an ACD device is being used.

Bilateral tension pneumothorax after acupuncture.

PubMed

Mohammad, Nurashikin

2018-04-19

Acupuncture is an ancient complementary medicine which is currently used worldwide. Many serious adverse events have been reported which include a spectrum of mild-to-fatal complications. However, the level of awareness with regard to complications is still low both to physicians and patients. We report a 63-year-old who presented with acute shortness of breath 2 hours after having had acupuncture. On examination, there was absent breath sound heard on the left lung and slightly reduced breath sound on the right lung. She had type 1 respiratory failure. Urgent chest radiograph confirmed bilateral pneumothorax which was more severe on the left with tension pneumothorax and mediastinal shift. Chest tubes were inserted bilaterally after failed needle aspiration attempts. Subsequently, the pneumothoraces resolved, and she was discharged well. The bilateral pneumothoraces caused by acupuncture were curable but could have been potentially fatal if diagnosis was delayed. This case report adds to the limited current literature on the complications of acupuncture leading to bilateral pneumothoraces. © BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Design of a Ram Accelerator mass launch system

NASA Technical Reports Server (NTRS)

1988-01-01

The Ram Accelerator, a chemically propelled, impulsive mass launch system, is presented as a viable concept for directly launching acceleration-insensitive payloads into low Earth orbit. The principles of propulsion are based on those of an airbreathing supersonic ramjet. The payload vehicle acts as the ramjet centerbody and travels through a fixed launch tube that acts as the ramjet outer cowling. The launch tube is filled with premixed gaseous fuel and oxidizer mixtures that combust at the base of the vehicle and produce thrust. Two modes of in-tube propulsion involving ramjet cycles are used in sequence to accelerate the vehicle from 0.7 km/sec to 9 km/sec. Requirements for placing a 2000 kg vehicle into a 500-km circular orbit, with a minimum amount of onboard rocket propellant for orbital maneuvers, are examined. It is shown that in-tube propulsion requirements dictate a launch tube length of 5.1 km to achieve an exit velocity of 9 km/sec, with peak accelerations not to exceed 1000 g's. Aerodynamic heating due to atmospheric transit requires minimal ablative protection and the vehicle retains a large percentage of its exit velocity. An indirect orbital insertion maneuver with aerobraking and two apogee burns is examined to minimize the required onboard propellant mass. An appropriate onboard propulsion system design to perform the required orbital maneuvers with minimum mass requirements is also determined. The structural designs of both the launch tube and the payload vehicle are examined using simple structural and finite element analysis for various materials.

Development of a 75-watt 60-GHz traveling-wave tube for intersatellite communications

NASA Technical Reports Server (NTRS)

Rousseau, A. L.; Tammaru, I.; Vaszari, J. P.

1988-01-01

This program covers the initial design and development of a 75 watt, 60 GHz traveling-wave tube for intersatellite communications. The objective frequency band was 59 to 64 GHz, with a minimum tube gain of 35 dB. The objective overall efficiency at saturation was 40 percent. The tube, designated the 961H, used a coupled-cavity interaction circuit with periodic permanent magnet beam focusing to minimize the weight. For efficiency enhancement, it incorporated a four-stage depressed collector capable of radiation cooling in space. The electron gun had a low-temperature (type-M) cathode and an isolated anode. Two tubes were built and tested; one feasibility model with a single-stage collector and one experimental model that incorporated the multistage collector.

Elimination characteristics of post-operative isoflurane levels in alveolar exhaled breath via PTR-MS analysis.

PubMed

Fernández Del Río, R; O'Hara, M E; Pemberton, P; Whitehouse, T; Mayhew, C A

2016-10-12

Isoflurane (1-chloro-2,2,2-trifluoroethyl difluoromethyl ether), C 3 H 2 ClF 5 O, is a commonly used inhalation anaesthetic. Using a proton transfer reaction mass spectrometer (PTR-MS) we have detected isoflurane in the breath of patients several weeks following major surgery. That isoflurane is detected in the breath of patients so long after being anaesthetised raises questions about when cognitive function has fully returned to a patient. Temporal profiles of isoflurane concentrations in breath are presented for five patients (F/M 3/2, mean age 50 years, min-max 36-58 years) who had undergone liver transplant surgery. In addition, results from a headspace analysis of isoflurane are presented so that the product ions resulting from the reactions of H 3 O + with isoflurane in PTR-MS could be easily identified in the absence of the complex chemical environment of breath. Six product ions were identified. In order of increasing m/z (using the 35 Cl isotope where appropriate) these are [Formula: see text] (m/z 51), CHFCl + (m/z 67), CF 3 CHCl + (m/z 117), C 3 F 4 OCl + (m/z 163), C 3 H 2 F 4 OCl + (m/z 165), and C 3 F 4 OCl + H 2 O (m/z 183). No protonated parent was detected. For the headspace study both clean air and CO 2 enriched clean air (4% CO 2 ) were used as buffer gases in the drift tube of the PTR-MS. The CO 2 enriched air was used to determine if exhaled breath would affect the product ion branching ratios. Importantly no significant differences were observed, and therefore for isoflurane the product ion distributions determined in a normal air mixture can be used for breath analysis. Given that PTR-MS can be operated under different reduced electric fields (E/N), the dependence of the product ion branching percentages for isoflurane on E/N (96-138 Td) are reported.

46 CFR 162.028-3 - Requirements.

Code of Federal Regulations, 2012 CFR

2012-10-01

... which are subjected to pressure, exclusive of the hose, shall be at least five times the maximum working... which will withstand a minimum bursting pressure of 6,000 p.s.i., and a discharge hose or tube which will withstand a minimum bursting pressure of 5,000 p.s.i. The hose shall be constructed with either a...

46 CFR 162.028-3 - Requirements.

Code of Federal Regulations, 2014 CFR

2014-10-01

... which are subjected to pressure, exclusive of the hose, shall be at least five times the maximum working... which will withstand a minimum bursting pressure of 6,000 p.s.i., and a discharge hose or tube which will withstand a minimum bursting pressure of 5,000 p.s.i. The hose shall be constructed with either a...

46 CFR 162.028-3 - Requirements.

Code of Federal Regulations, 2013 CFR

2013-10-01

... which are subjected to pressure, exclusive of the hose, shall be at least five times the maximum working... which will withstand a minimum bursting pressure of 6,000 p.s.i., and a discharge hose or tube which will withstand a minimum bursting pressure of 5,000 p.s.i. The hose shall be constructed with either a...

Enhancing the sensitivity of mid-IR quantum cascade laser-based cavity-enhanced absorption spectroscopy using RF current perturbation.

PubMed

Manfred, Katherine M; Kirkbride, James M R; Ciaffoni, Luca; Peverall, Robert; Ritchie, Grant A D

2014-12-15

The sensitivity of mid-IR quantum cascade laser (QCL) off-axis cavity-enhanced absorption spectroscopy (CEAS), often limited by cavity mode structure and diffraction losses, was enhanced by applying a broadband RF noise to the laser current. A pump-probe measurement demonstrated that the addition of bandwidth-limited white noise effectively increased the laser linewidth, thereby reducing mode structure associated with CEAS. The broadband noise source offers a more sensitive, more robust alternative to applying single-frequency noise to the laser. Analysis of CEAS measurements of a CO(2) absorption feature at 1890  cm(-1) averaged over 100 ms yielded a minimum detectable absorption of 5.5×10(-3)  Hz(-1/2) in the presence of broadband RF perturbation, nearly a tenfold improvement over the unperturbed regime. The short acquisition time makes this technique suitable for breath applications requiring breath-by-breath gas concentration information.

Comparison of power-plant condenser cooling-water fouling rates for spirally-indented and plain tubes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rabas, T.; Panchal, C.; Sasscer, D.

1991-01-01

This paper presents the fouling rates for twelve TVA power-plant condensers, nine of which were retubed with an enhanced tube. The overall heat-transfer coefficients were calculated from logged field data taken over periods from one to ten years. The fouling resistances were calculated with the separate-resistance method and with a bundle correction factor to the condensing, single-tube Nusselt prediction. The fouling rates with the enhanced tubes ranged from about the same as to about twice that of the plain tubes. The thermal performance with the enhanced tubes remained superior to that obtained with plain-tubes for more than a year withoutmore » cleaning. After one year of operation, the enhanced-tube fouling resistance values were less than the minimum value of the TEMA Standards and the plain-tube fouling resistance values were always less than one half of this value. After shutdown cleaning, the thermal performance values for both tubes were restored to essentially the new, clean levels. 28 refs., 9 figs., 2 tabs.« less

Thermodynamic Cycle and CFD Analyses for Hydrogen Fueled Air-breathing Pulse Detonation Engines

NASA Technical Reports Server (NTRS)

Povinelli, Louis A.; Yungster, Shaye

2002-01-01

This paper presents the results of a thermodynamic cycle analysis of a pulse detonation engine (PDE) using a hydrogen-air mixture at static conditions. The cycle performance results, namely the specific thrust, fuel consumption and impulse are compared to a single cycle CFD analysis for a detonation tube which considers finite rate chemistry. The differences in the impulse values were indicative of the additional performance potential attainable in a PDE.

Endotracheal intubation - A life saving procedure, still potential hazardous to upper airway: A case report.

PubMed

Afreen, Mahrukh; Ansari, Murtaza Ahsan

2015-12-01

Endotracheal intubation plays a key role in the management of upper airway obstruction in emergency situations. It is non-invasive and easily learned technique by medical professionals as compared to other more skilled, surgical procedures, e.g., tracheostomy and cricothyrotomies etc. But prolonged intubation may result in numerous complications, most notorious being tracheoesophageal fistula and narrowing of subglottic area. We report a profile of a patient who had been diagnosed as case of Guillian-Barre Syndrome, had difficulty in breathing due to paralysis of respiratory muscles. The patient was admitted in Medical Intensive Care Unit (MICU) for 40 days and was kept on artificial breathing through endotracheal intubation, which remained in place for 19 days. Later tracheostomy was performed. Patient ultimately developed severe subglottic stenosis and became dependent on tracheostomy tube.

Phenotyping of Sleep-Disordered Breathing in Patients With Chronic Heart Failure With Reduced Ejection Fraction-the SchlaHF Registry.

PubMed

Arzt, Michael; Oldenburg, Olaf; Graml, Andrea; Erdmann, Erland; Teschler, Helmut; Wegscheider, Karl; Suling, Anna; Woehrle, Holger

2017-11-29

Different sleep-disordered breathing (SDB) phenotypes, including coexisting obstructive and central sleep apnea (OSA-CSA), have not yet been characterized in a large sample of patients with heart failure and reduced ejection fraction (HFrEF) receiving guideline-based therapies. Therefore, the aim of the present study was to determine the proportion of OSA, CSA, and OSA-CSA, as well as periodic breathing, in HFrEF patients with SDB. The German SchlaHF registry enrolled patients with HFrEF receiving guideline-based therapies, who underwent portable SDB monitoring. Polysomnography (n=2365) was performed in patients with suspected SDB. Type of SDB (OSA, CSA, or OSA-CSA), the occurrence of periodic breathing (proportion of Cheyne-Stokes respiration ≥20%), and blood gases were determined in 1557 HFrEF patients with confirmed SDB. OSA, OSA-CSA, and CSA were found in 29%, 40%, and 31% of patients, respectively; 41% showed periodic breathing. Characteristics differed significantly among SDB groups and in those with versus without periodic breathing. There was a relationship between greater proportions of CSA and the presence of periodic breathing. Risk factors for having CSA rather than OSA were male sex, older age, presence of atrial fibrillation, lower ejection fraction, and lower awake carbon dioxide pressure (pco 2 ). Periodic breathing was more likely in men, patients with atrial fibrillation, older patients, and as left ventricular ejection fraction and awake pco 2 decreased, and less likely as body mass index increased and minimum oxygen saturation decreased. SchlaHF data show that there is wide interindividual variability in the SDB phenotype of HFrEF patients, suggesting that individualized management is appropriate. URL: https://www.clinicaltrials.gov/. Unique identifier: NCT01500759. © 2017 The Authors and ResMed Germany Inc. Published on behalf of the American Heart Association, Inc., by Wiley.

Sensing Technologies for Detection of Acetone in Human Breath for Diabetes Diagnosis and Monitoring

PubMed Central

Saasa, Valentine; Malwela, Thomas; Beukes, Mervyn; Mokgotho, Matlou; Liu, Chaun-Pu; Mwakikunga, Bonex

2018-01-01

The review describes the technologies used in the field of breath analysis to diagnose and monitor diabetes mellitus. Currently the diagnosis and monitoring of blood glucose and ketone bodies that are used in clinical studies involve the use of blood tests. This method entails pricking fingers for a drop of blood and placing a drop on a sensitive area of a strip which is pre-inserted into an electronic reading instrument. Furthermore, it is painful, invasive and expensive, and can be unsafe if proper handling is not undertaken. Human breath analysis offers a non-invasive and rapid method for detecting various volatile organic compounds thatare indicators for different diseases. In patients with diabetes mellitus, the body produces excess amounts of ketones such as acetoacetate, beta-hydroxybutyrate and acetone. Acetone is exhaled during respiration. The production of acetone is a result of the body metabolising fats instead of glucose to produce energy. There are various techniques that are used to analyse exhaled breath including Gas Chromatography Mass Spectrometry (GC–MS), Proton Transfer Reaction Mass Spectrometry (PTR–MS), Selected Ion Flow Tube-Mass Spectrometry (SIFT–MS), laser photoacoustic spectrometry and so on. All these techniques are not portable, therefore this review places emphasis on how nanotechnology, through semiconductor sensing nanomaterials, has the potential to help individuals living with diabetes mellitus monitor their disease with cheap and portable devices. PMID:29385067

Spectroscopic evidence for the origin of the dumbbell cyclic voltammogram of single-walled carbon nanotubes.

PubMed

Al-zubaidi, Ayar; Ishii, Yosuke; Yamada, Saki; Matsushita, Tomohiro; Kawasaki, Shinji

2013-12-21

We investigated the changes in charge carrier density responsible for the dumbbell-like cyclic voltammogram of single-walled carbon nanotubes (SWCNTs) used as electric double layer capacitor electrodes. We utilized in situ Raman spectroscopy of SWCNTs in the potential range where the dumbbell voltammogram is observed and electric double layer charging would be the dominant mechanism. The study revealed that, unexpectedly, the spectroscopic changes coinciding with the dumbbell steps on the voltammogram occur more sharply in metallic tubes, as seen from (1) the sudden enhancement in the intensity of the BWF Breit-Wigner-Fano (BWF) feature, (2) a considerably more significant frequency upshift of G(+) and G' bands, and (3) a drop in radial breathing mode intensity, compared to those in the spectra of semiconducting tubes. In addition, the spectroscopic changes observed with open-end SWCNT samples were more defined and correlated more accurately with the electronic structure of the tubes compared to those observed with closed-end SWCNTs.

[Use of the air-Q laryngeal airway and tube exchanger in a case of difficult tracheal extubation after maxillectomy].

PubMed

Komasawa, Nobuyasu; Ueki, Ryusuke; Iwasaki, Yohei; Tatara, Tsuneo; Tashiro, Chikara; Kaminoh, Yoshiroh

2012-10-01

A 79-year-old man was diagnosed with maxillary cancer and underwent total maxillectomy under general anesthesia. The oropharyngeal airway was needed for efficient mask ventilation during anesthesia induction. The maxilla was totally resected and reconstructed with skin from a femoral flap. Tracheal extubation was considered to be difficult given that mask ventilation was contraindicated due to reconstruction of the maxilla. After inserting a tube exchanger (TE) into the trachea, the tracheal tube was exchanged with an air-Q laryngeal airway through the TE. After confirming effective ventilation with the air-Q mask, the patient was awakened from anesthesia. We confirmed sufficient spontaneous breathing and no active bleeding in the pharynx. After re-inserting the TE thorough air-Q, the air-Q was removed, followed by removal of the TE. These findings suggest that the air-Q and TE were effective in a case of difficult extubation after maxillectomy.

The Humidity in a Low-Flow Dräger Fabius Anesthesia Workstation with or without Thermal Insulation or a Heat and Moisture Exchanger: A Prospective Randomized Clinical Trial

PubMed Central

de Oliveira, Sergius A. R.; Lucio, Lorena M. C.; Modolo, Norma S. P.; Hayashi, Yoko; Braz, Mariana G.; de Carvalho, Lídia R.; Braz, Leandro G.; Braz, José Reinaldo C.

2017-01-01

Background During anesthesia, as compared with intensive care, the time of the tracheal intubation is much shorter. An inhaled gas minimum humidity of 20 mgH2O.L-1 is recommended to reduce the deleterious effects of dry gas on the airways during anesthesia with tracheal intubation. The Fabius GS Premium® anesthesia workstation (Dräger Medical, Lübeck, Germany) has a built-in hotplate to heat gases in the breathing circuit. A heat and moisture exchanger (HME) is used to further heat and humidify the inhaled gas. The humidity of the gases in the breathing circuit is influenced by the ambient temperature. We compared the humidity of the inhaled gases from a low-flow Fabius anesthesia workstation with or without thermal insulation (TI) of the breathing circuit and with or without an HME. Methods We conducted a prospective randomized trial in 41 adult female patients who underwent elective abdominal surgery. The patients were allocated into four groups according to the devices used to ventilate their lungs using a Dräger Fabius anesthesia workstation with a low gas flow (1 L.min-1): control, with TI, with an HME or with TI and an HME (TIHME). The mean temperature and humidity of the inhaled gases were measured during 2-h after connecting the patients to the breathing circuit. Results The mean inhaled gas temperature and absolute humidity were higher in the HME (29.2±1.3°C; 28.1±2.3 mgH2O·L-1) and TIHME (30.1±1.2°C; 29.4±2.0 mgH2O·L-1) groups compared with the control (27.5±1.0°C; 25.0±1.8 mgH2O·L-1) and TI (27.2±1.1°C; 24.9±1.8 mgH2O·L-1) groups (P = 0.003 and P<0.001, respectively). Conclusions The low-flow Fabius GS Premium breathing circuit provides the minimum humidity level of inhaled gases to avoid damage to the tracheobronchial epithelia during anesthesia. TI of the breathing circuit does not increase the humidity of the inhaled gases, whereas inserting an HME increases the moisture of the inhaled gases closer to physiological values. PMID:28129353

14 CFR 23.1443 - Minimum mass flow of supplemental oxygen.

Code of Federal Regulations, 2012 CFR

2012-01-01

..., minus 47 mm. Hg, which is the tracheal pressure displaced by water vapor pressure when the breathed air becomes saturated with water vapor at 37 °C). (2) STPD means Standard, Temperature, and Pressure, Dry (which is, 0 °C at 760 mm. Hg with no water vapor). [Doc. No. 26344, 58 FR 18978, Apr. 9, 1993] § 23.1443...

The pharmacological effects of intramuscular administration of alfaxalone combined with medetomidine and butorphanol in dogs.

PubMed

Tamura, Jun; Hatakeyama, Naohiro; Ishizuka, Tomohito; Itami, Takaharu; Fukui, Sho; Miyoshi, Kenjiro; Sano, Tadashi; Pasloske, Kirby; Yamashita, Kazuto

2016-07-01

The pharmacological effects of intramuscular (IM) administration of alfaxalone combined with medetomidine and butorphanol were evaluated in 6 healthy beagle dogs. Each dog received three treatments with a minimum 10-day interval between treatments. The dogs received an IM injection of alfaxalone 2.5 mg/kg (ALFX), medetomidine 2.5 µg/kg and butorphanol 0.25 mg/kg (MB), or their combination (MBA) 1 hr after the recovery from their instrumentation. Endotracheal intubation was attempted, and dogs were allowed to breath room air. Neuro-depressive effects (behavior changes and subjective scores) and cardiorespiratory parameters (rectal temperature, heart rate, respiratory rate, direct blood pressure, central venous pressure and blood gases) were evaluated before and at 2 to 120 min after IM treatment. Each dog became lateral recumbency, except for two dogs administered the MB treatment. The duration was longer in the MBA treatment compared with the ALFX treatment (100 ± 48 min vs 46 ± 13 min). Maintenance of the endotracheal tube lasted for 60 ± 24 min in five dogs administered the MBA treatment and for 20 min in one dog administered the ALFX treatment. Cardiorespiratory variables were maintained within clinically acceptable ranges, although decreases in heart and respiratory rates, and increases in central venous pressure occurred after the MBA and MB treatments. The MBA treatment provided an anesthetic effect that permitted endotracheal intubation without severe cardiorespiratory depression in healthy dogs.

Modeling Respiratory Gas Dynamics in the Aviator’s Breathing System. Volume 2. Appendices

DTIC Science & Technology

1994-05-01

Rideout, at at. Dfference-Differentlat Equations for Fluid C... Flow in Distensible Tubes. IEEE Transactions on Bio-Medlcat C... Enginhering. Vot INE-14...McGraw-Hill; 1970; Chapter 13: 433-450. 12. Astrand, PO; Saltin, B. Oxygen uptake during the first minutes of heavy muscular exercise. J Appl Physiol...1802-1814; 1986. 233. Linehan, JH; Haworth, ST; Nelin, LD; Krenz, GS; Dawson, CA. A Simple Distensible Vessel Model for Interpreting Pulmonary

In-depth survey report: Assisting furniture strippers in reducing the risk from methylene chloride stripping formulations at Los Angeles Stripping and Refinishing Center, Los Angeles, California

DOE Office of Scientific and Technical Information (OSTI.GOV)

Estill, C.F.; Kovein, R.J.; Jones, J.H.

1999-03-26

The National Institute for Occupational Safety and Health (NIOSH) is currently conducting research on ventilation controls to reduce furniture stripping exposures to methylene chloride to the OSHA PEL of 25 ppm. Low cost ventilation systems were designed by NIOSH researchers along with Benny Bixenman of Benco Sales, Inc. (Forney, TX). The controls were constructed and installed by Benco Sales. This report compares the methylene chloride levels of one worker stripping furniture using the recently installed ventilation controls and using the existing controls. During the survey, two different chemical stripping solutions (a standard formulation and a low methylene chloride content formulation)more » were used and compared. This survey tested three control combinations: (1) new ventilation, low methylene chloride stripper, (2) new ventilation, standard stripping solution, and (3) old ventilation, standard stripping solution. During each test, sorbent tube sampling and real-time sampling were employed. Sorbent tube, data collected in the worker's breathing zone, ranged from 300 to 387 ppm. Real-time data showed breathing zone exposures to range from 211 to 383 ppm while stripping and 164 to 230 ppm while rinsing. Data were inconclusive to determine which ventilation system or stripping solution produced the lowest exposures. Recommendations are made in the report to improve the newly installed ventilation controls.« less

Condensation heat transfer and pressure drop of R-410A in a 7.0 mm O.D. microfin tube at low mass fluxes

NASA Astrophysics Data System (ADS)

Kim, Nae-Hyun

2016-12-01

R-410A condensation heat transfer and pressure drop data are provided for a 7.0 mm O.D. microfin tube at low mass fluxes (50-250 kg/m2 s). The heat transfer coefficient of the microfin tube shows a minimum behavior with the mass flux. At a low mass flux, where flow pattern is stratified, condensation induced by surface tension by microfins overwhelms condensation induced by shear, and the heat transfer coefficient decreases as mass flux increases. At a high mass flux, where flow pattern is annular, condensation induced by shear governs the heat transfer, and the heat transfer coefficient increases as mass flux increases. The pressure drop of the microfin tube is larger than that of the smooth tube at the annular flow regime. On the contrary, the pressure drop of the smooth tube is larger than that of the microfin tube at the stratified flow regime.

Air-Flow-Driven Triboelectric Nanogenerators for Self-Powered Real-Time Respiratory Monitoring.

PubMed

Wang, Meng; Zhang, Jiahao; Tang, Yingjie; Li, Jun; Zhang, Baosen; Liang, Erjun; Mao, Yanchao; Wang, Xudong

2018-06-04

Respiration is one of the most important vital signs of humans, and respiratory monitoring plays an important role in physical health management. A low-cost and convenient real-time respiratory monitoring system is extremely desirable. In this work, we demonstrated an air-flow-driven triboelectric nanogenerator (TENG) for self-powered real-time respiratory monitoring by converting mechanical energy of human respiration into electric output signals. The operation of the TENG was based on the air-flow-driven vibration of a flexible nanostructured polytetrafluoroethylene (n-PTFE) thin film in an acrylic tube. This TENG can generate distinct real-time electric signals when exposed to the air flow from different breath behaviors. It was also found that the accumulative charge transferred in breath sensing corresponds well to the total volume of air exchanged during the respiration process. Based on this TENG device, an intelligent wireless respiratory monitoring and alert system was further developed, which used the TENG signal to directly trigger a wireless alarm or dial a cell phone to provide timely alerts in response to breath behavior changes. This research offers a promising solution for developing self-powered real-time respiratory monitoring devices.

Plasma dynamics on current-carrying magnetic flux tubes

NASA Technical Reports Server (NTRS)

Swift, Daniel W.

1992-01-01

A 1D numerical simulation is used to investigate the evolution of a plasma in a current-carrying magnetic flux tube of variable cross section. A large potential difference, parallel to the magnetic field, is applied across the domain. The result is that density minimum tends to deepen, primarily in the cathode end, and the entire potential drop becomes concentrated across the region of density minimum. The evolution of the simulation shows some sensitivity to particle boundary conditions, but the simulations inevitably evolve into a final state with a nearly stationary double layer near the cathode end. The simulation results are at sufficient variance with observations that it appears unlikely that auroral electrons can be explained by a simple process of acceleration through a field-aligned potential drop.

Respiratory reflexes in response to nasal administration of halothane to anesthetized, spontaneously breathing dogs.

PubMed

Mutoh, T; Kanamaru, A; Tsubone, H; Nishimura, R; Sasaki, N

2000-03-01

To characterize and determine the sensory innervation of respiratory reflexes elicited by nasal administration of halothane to dogs. 10 healthy Beagles. Dogs underwent permanent tracheostomy and, 2 to 3 weeks later, were anesthetized with thiopental and alpha-chloralose administered IV. The nasal passages were functionally isolated so that halothane could be administered to the nasal passages while dogs were breathing 100% O2 via the tracheostomy. Respiratory reflexes in response to administration of halothane at concentrations of 1.25, 1.75, and 2.5 times the minimum alveolar concentration (MAC), and 5% (administered in 100% O2 at a flow rate of 5 L/min) were recorded. Reflexes in response to administration of 5% halothane were also recorded following transection of the infraorbital nerve, transection of the caudal nasal nerve, and nasal administration of lidocaine. Nasal administration of halothane induced an inhibition of breathing characterized by a dose-dependent increase in expiratory time and a resultant decrease in expired volume per unit time. Effects were noticeable immediately after the onset of halothane administration and lasted until its cessation. Reflex responses to halothane administration were attenuated by transection of the caudal nasal nerve and by nasal administration of lidocaine, but transection of the infraorbital nerve had no effect. Nasal administration of halothane at concentrations generally used for mask induction of anesthesia induces reflex inhibition of breathing. Afferent fibers in the caudal nasal nerve appear to play an important role in the reflex inhibition of breathing induced by halothane administration.

Respiration rate detection based on intensity modulation using plastic optical fiber

NASA Astrophysics Data System (ADS)

Anwar, Zawawi Mohd; Ziran Nurul Sufia, Nor; Hadi, Manap

2017-11-01

This paper presents the implementation of respiration rate measurement via a simple intensity-based optical fiber sensor using optical fiber technology. The breathing rate is measured based on the light intensity variation due to the longitudinal gap changes between two separated fibers. In order to monitor the breathing rate continuously, the output from the photodetector conditioning circuit is connected to a low-cost Arduino kit. At the sensing point, two optical fiber cables are positioned in series with a small gap and fitted inside a transparent plastic tube. To ensure smooth movement of the fiber during inhale and exhale processes as well as to maintain the gap of the fiber during idle condition, the fiber is attached firmly to a stretchable bandage. This study shows that this simple fiber arrangement can be applied to detect respiration activity which might be critical for patient monitoring.

Conditioning of inspired air by a hygroscopic condenser humidifier.

PubMed

Primiano, F P; Moranz, M E; Montague, F W; Miller, R B; Sachs, D P

1984-08-01

The heat and water content of inspired air is critical to the pulmonary viability of patients with artificial airways. By continuously measuring gas conditions in the ventilator circuits of 6 adult ICU patients, we studied the heat and water reclaimed from expired air by a hygroscopic condenser humidifier (HCH) in the circuit. Temperature, partial pressure of water vapor (PH2O) and relative humidity (RH) were determined at the tracheal outlet of the endotracheal tube. The HCH was 63% efficient; the end-inspiratory gas delivered to the patients averaged 30.9 degrees C with a PH2O of 32.5 mm Hg and an RH of 97.3% or, equivalently, an RH of 69.2% referenced to 37 degrees C. These values are lower than those reported in the literature for gas in the trachea during nose breathing of ambient air, but greater than the values reported for mouth breathing of ambient air.

Anesthesia equipment malfunction: origins and clinical recognition.

PubMed Central

McIntyre, J. W.

1979-01-01

Equipment malfunction is a problem of particular importance during anesthesia and resuscitation. A review of published reports shows that the most common clinical events involve endotracheal tubes, the inspired oxygen concentration, the volume of inspired anesthetic vapours and gases, and pressures in the breathing or ventilation system. It is concluded that protection of a patient from equipment malfunction depends on: (a) appropriate application of standards set by a national standards association; (b) careful evaluation of equipment prior to purchase; (c) comprehension of equipment function by the user; (d) conscientious routine servicing of all systems concerned with anesthesia and resuscitation, and checking after service and before clinical use; (e) preanesthesia testing of equipment, including the use of an oxygen analyser in the breathing circuit; (f) early inclusion of equipment malfunction in the differential diagnosis of events during anesthesia; and (g) rapid action that cannot present a new hazard to the patient to correct the results of apparatus malfunction. PMID:436069

Final bubble lengths for aqueous foam coarsened in a horizontal cylinder

NASA Astrophysics Data System (ADS)

Sebag, V.; Roth, A. E.; Durian, D. J.

2011-12-01

We report on length statistics measured for bubbles in the equilibrium bamboo state, achieved by the coarsening of aqueous foam in long cylindrical tubes, such that the soap films are all flat and perpendicular to the axis of the tube. The average bubble length is found to be 0.88 times the tube diameter, independent of variation of the liquid filling fraction by a factor of nearly three. The actual distribution is well-approximated by a shifted Rayleigh form, with a minimum bubble size of 0.28 tube diameters. And, perhaps surprisingly, no correlations are found in the lengths of neighboring bubbles. The observed length distribution agrees with that of Fortes et al. for short bubbles, but not for long bubbles.

Exploratory breath analyses for assessing toxic dermal exposures of firefighters during suppression of structural burns.

PubMed

Pleil, Joachim D; Stiegel, Matthew A; Fent, Kenneth W

2014-09-01

Firefighters wear fireproof clothing and self-contained breathing apparatus (SCBA) during rescue and fire suppression activities to protect against acute effects from heat and toxic chemicals. Fire services are also concerned about long-term health outcomes from chemical exposures over a working lifetime, in particular about low-level exposures that might serve as initiating events for adverse outcome pathways (AOP) leading to cancer. As part of a larger US National Institute for Occupational Safety and Health (NIOSH) study of dermal exposure protection from safety gear used by the City of Chicago firefighters, we collected pre- and post-fire fighting breath samples and analyzed for single-ring and polycyclic aromatic hydrocarbons as bioindicators of occupational exposure to gas-phase toxicants. Under the assumption that SCBA protects completely against inhalation exposures, any changes in the exhaled profile of combustion products were attributed to dermal exposures from gas and particle penetration through the protective clothing. Two separate rounds of firefighting activity were performed each with 15 firefighters per round. Exhaled breath samples were collected onto adsorbent tubes and analyzed with gas-chromatography-mass spectrometry (GC-MS) with a targeted approach using selective ion monitoring. We found that single ring aromatics and some PAHs were statistically elevated in post-firefighting samples of some individuals, suggesting that fire protective gear may allow for dermal exposures to airborne contaminants. However, in comparison to a previous occupational study of Air Force maintenance personnel where similar compounds were measured, these exposures are much lower suggesting that firefighters' gear is very effective. This study suggests that exhaled breath sampling and analysis for specific targeted compounds is a suitable method for assessing systemic dermal exposure in a simple and non-invasive manner.

Effect of leak and breathing pattern on the accuracy of tidal volume estimation by commercial home ventilators: a bench study.

PubMed

Luján, Manel; Sogo, Ana; Pomares, Xavier; Monsó, Eduard; Sales, Bernat; Blanch, Lluís

2013-05-01

New home ventilators are able to provide clinicians data of interest through built-in software. Monitoring of tidal volume (VT) is a key point in the assessment of the efficacy of home mechanical ventilation. To assess the reliability of the VT provided by 5 ventilators in a bench test. Five commercial ventilators from 4 different manufacturers were tested in pressure support mode with the help of a breathing simulator under different conditions of mechanical respiratory pattern, inflation pressure, and intentional leakage. Values provided by the built-in software of each ventilator were compared breath to breath with the VT monitored through an external pneumotachograph. Ten breaths for each condition were compared for every tested situation. All tested ventilators underestimated VT (ranges of -21.7 mL to -83.5 mL, which corresponded to -3.6% to -14.7% of the externally measured VT). A direct relationship between leak and underestimation was found in 4 ventilators, with higher underestimations of the VT when the leakage increased, ranging between -2.27% and -5.42% for each 10 L/min increase in the leakage. A ventilator that included an algorithm that computes the pressure loss through the tube as a function of the flow exiting the ventilator had the minimal effect of leaks on the estimation of VT (0.3%). In 3 ventilators the underestimation was also influenced by mechanical pattern (lower underestimation with restrictive, and higher with obstructive). The inclusion of algorithms that calculate the pressure loss as a function of the flow exiting the ventilator in commercial models may increase the reliability of VT estimation.

Bio-sniffer (gas-phase biosensor) with secondary alcohol dehydrogenase (S-ADH) for determination of isopropanol in exhaled air as a potential volatile biomarker.

PubMed

Chien, Po-Jen; Suzuki, Takuma; Tsujii, Masato; Ye, Ming; Toma, Koji; Arakawa, Takahiro; Iwasaki, Yasuhiko; Mitsubayashi, Kohji

2017-05-15

Exhaled breath analysis has attracted lots of researchers attention in the past decades due to its advantages such as its non-invasive property and the possibility of continuous monitoring. In addition, several volatile organic compounds in breath have been identified as biomarkers for some diseases. Particularly, studies have pointed out that concentration of isopropanol (IPA) in exhaled air might relate with certain illnesses such as liver disease, chronic obstructive pulmonary (COPD), and lung cancer. In this study, a highly sensitive and selective biochemical gas sensor (bio-sniffer) for the breath IPA concentration determination was constructed and optimized. This bio-sniffer measures the concentration of IPA according to the fluorescence intensity of oxidized nicotinamide adenine dinucleotide (NADH), which was produced by an enzymatic reaction of secondary alcohol dehydrogenase (S-ADH). The NADH detection system employed an UV-LED as the excitation light, and a highly sensitive photomultiplier tube (PMT) as a fluorescence intensity detector. A gas-sensing region was developed using an optical fiber probe equipped with a flow-cell and enzyme immobilized membrane, and connected to the NADH measurement system. The calibration range of the IPA bio-sniffer was confirmed from 1ppb to 9060ppb that was comparable to other IPA analysis methods. The results of the analysis of breath IPA concentration in healthy subjects using the bio-sniffer showed a mean concentration of 16.0ppb, which was similar to other studies. These results have demonstrated that this highly sensitive and selective bio-sniffer could be used to measure the IPA in exhaled air, and it is expected to apply for breath IPA research and investigation of biomarkers for clinical diagnosis. Copyright © 2016 Elsevier B.V. All rights reserved.

Analysis of breath volatile organic compounds as a noninvasive tool to diagnose nonalcoholic fatty liver disease in children.

PubMed

Alkhouri, Naim; Cikach, Frank; Eng, Katharine; Moses, Jonathan; Patel, Nishaben; Yan, Chen; Hanouneh, Ibrahim; Grove, David; Lopez, Rocio; Dweik, Raed

2014-01-01

Nonalcoholic fatty liver disease (NAFLD) is one of the most common complications of childhood obesity. Our objective was to investigate the association of breath volatile organic compounds with the diagnosis of NAFLD in children. Patients were screened with an ultrasound of the abdomen to evaluate for NAFLD. Exhaled breath was collected and analyzed per protocol using selective ion flow tube mass spectrometry (SIFT-MS). Sixty patients were included in the study (37 with NAFLD and 23 with normal liver). All children were overweight or obese. The mean age was 14.1±2.8 years and 50% were female. A comparison of the SIFT-MS results of patients with NAFLD with those with normal liver on ultrasound revealed differences in concentration of more than 15 compounds. A panel of four volatile organic compounds can identify the presence of NAFLD with good accuracy (area under the receiver operating characteristic curve of 0.913 in the training set and 0.763 in the validation set). Breath isoprene, acetone, trimethylamine, acetaldehyde, and pentane were significantly higher in the NAFLD group compared with normal liver group (14.7 ppb vs. 8.9 for isoprene; 71.7 vs. 36.9 for acetone; 5.0 vs. 3.2 for trimethylamine; 35.1 vs. 26.0 for acetaldehyde; and 13.3 vs. 8.8 for pentane, P<0.05 for all). Exhaled breath analysis is a promising noninvasive method to detect fatty liver in children. Isoprene, acetone, trimethylamine, acetaldehyde, and pentane are novel biomarkers that may help to gain insight into pathophysiological processes leading to the development of NAFLD.

14 CFR 29.1323 - Airspeed indicating system.

Code of Federal Regulations, 2010 CFR

2010-01-01

... minimum practicable instrument calibration error when the corresponding pitot and static pressures are... pitot tube or an equivalent means of preventing malfunction due to icing. [Doc. No. 5084, 29 FR 16150...

A salivary incubation test for evaluation of oral malodor: a pilot study.

PubMed

Quirynen, Marc; Zhao, Hong; Avontroodt, Pieter; Soers, Catherine; Pauwels, Martine; Coucke, Wim; van Steenberghe, Daniel

2003-07-01

Breath odor is scored by different techniques, each with its own shortcomings. Organoleptic ratings are uncomfortable for the patient, subjective, influenced by external parameters including food and cosmetics, and especially lack international calibration. Portable sulphide monitors are relatively expensive and neglect several major malodorous molecules (e.g., butyric and propionic acids, putrescine, and cadaverine). Gas chromatography necessitates expensive devices and experienced technicians. This pilot study explored the applicability of a new technique (saliva incubation) by comparing its discrimination power, in a morning bad breath inhibition study of antiseptics, to those of hydrogen sulphide (H2S) measurement devices and organoleptic ratings. After a professional cleaning, 8 periodontally healthy students abstained from all means of mechanical plaque control for 5 experimental periods of 7 days, with intervening washout periods of at least 2 weeks. During each experimental period, the students rinsed only twice daily with different antiseptics. At day 7, morning breath was scored clinically (volatile sulphide compound [VSC] level and organoleptic ratings), and 1.5 ml of saliva was collected and divided between 3 glass tubes that were sealed and incubated (37 degrees C, anaerobic chamber). Immediately after collection and after 3 and 6 hours of incubation, the headspace air in one of the tubes was examined for VSC production and organoleptic measurements. The investigations of the incubated saliva correlated well with the 7-day intraoral VSC recordings and organoleptic ratings (P < or = 0.005). Moreover, evaluations showed a similar interproduct ranking for their efficacy in malodor control. The power analyses indicated a higher discrimination power for the saliva incubation test than for the intraoral registrations. The strong correlation between odor production of incubated saliva and clinical assessments suggests that the saliva incubation test may be used as an indirect method to measure oral malodor and can be employed to investigate the antimalodor effectiveness of oral hygiene products.

Vibrational energy transfer between carbon nanotubes and liquid water: a molecular dynamics study.

PubMed

Nelson, Tammie R; Chaban, Vitaly V; Kalugin, Oleg N; Prezhdo, Oleg V

2010-04-08

The rates and magnitudes of vibrational energy transfer between single-wall carbon nanotubes (CNTs) and water are investigated by classical molecular dynamics. The interactions between the CNT and solvent confined inside of the tube, the CNT and solvent surrounding the tube, as well as the solvent inside and outside of the tube are considered for the (11,11), (15,15), and (19,19) armchair CNTs. The vibrational energy transfer exhibits two time scales, subpicosecond and picosecond, of roughly equal importance. Solvent molecules confined within CNTs are more strongly coupled to the tubes than the outside molecules. The energy exchange is facilitated by slow collective motions, including CNT radial breathing modes (RBM). The transfer rate between CNTs and the inside solvent shows strong dependence on the CNT diameter. In smaller tubes, the transfer is faster and the solvent coupling to RBMs is stronger. The magnitude of the CNT-outside solvent interaction scales with the CNT surface area, while that of the CNT-inside solvent exhibits scaling that is intermediate between the CNT volume and surface. The Coulomb interaction between the solvent molecules inside and outside of the CNTs is much weaker than the CNT-solvent interactions. The results indicate that the excitation energy supplied to CNTs in chemical and biological applications is rapidly deposited to the active molecular agents and should remain localized sufficiently long in order to perform the desired function.

Volatile organic compounds in exhaled breath in a healthy population: effect of tobacco smoking.

PubMed

Jareño-Esteban, José Javier; Muñoz-Lucas, M Ángeles; Carrillo-Aranda, Belén; Maldonado-Sanz, José Ángel; de Granda-Orive, Ignacio; Aguilar-Ros, Antonio; Civera-Tejuca, Concepción; Gutiérrez-Ortega, Carlos; Callol-Sánchez, Luis Miguel

2013-11-01

Tobacco smoke is a source of free radicals and reactive oxygen and nitrogen species, which are the main causes of oxidative stress. The analysis of volatile organic compounds (VOC) in exhaled breath is an indirect method of measuring the level of oxidative stress that occurs in the airways caused by tobacco consumption. The aim of this study was to determine whether smoking influences the production of VOC, in a clinically healthy population. Exhaled breath from 89 healthy volunteers, divided into three groups (non-smokers, ex-smokers and smokers) was analysed. Samples were collected using Bio-VOC® devices and transferred to universal desorption tubes. Chemical compounds were analysed by thermal desorption, gas chromatography and mass spectrometry. We analysed hexanal, heptanal, octanal, nonanal, nonanoic acid and propanoic acid, all identified by retention time and mass spectra referenced in the NIST 08 mass spectral library; confirmation was carried out using reference standards of the pure chemical compound. These VOC were found in very low concentrations. Only nonanal showed significant quantitative and qualitative statistical differences among the study groups. Nonanal concentration is dependent on smoking, but is independent of the amount of tobacco consumed, age and gender. Nonanal in exhaled breath is associated with tobacco consumption, current or previous. Nonanal is a sub-product of the destruction of the cell membrane, and its finding may be indicative of cell damage in smokers. This result appears in many farmers who smoke. Copyright © 2013 SEPAR. Published by Elsevier Espana. All rights reserved.

High temperature heat exchangers for gas turbines and future hypersonic air breathing propulsion

NASA Astrophysics Data System (ADS)

Avran, Patrick; Bernard, Pierre

After surveying the results of ONERA's investigations to date of metallic and ceramic heat exchangers applicable to automotive and aircraft powerplants, which are primarily of finned-tube counterflow configuration, attention is given to the influence of heat-exchanger effectiveness on fuel consumption and exchanger dimensions and weight. Emphasis is placed on the results of studies of cryogenic heat exchangers used by airbreathing hypersonic propulsion systems. The numerical codes developed by ONERA for the modeling of heat exchanger thermodynamics are evaluated.

Heat and moisture exchangers and breathing system filters: their use in anaesthesia and intensive care. Part 1 - history, principles and efficiency.

PubMed

Wilkes, A R

2011-01-01

Heat and moisture exchangers and breathing system filters are intended to replace the normal warming, humidifying and filtering functions of the upper airways when these structures are bypassed during anaesthesia and intensive care. Guidance on their use continues to evolve. The aim of this part of the review is to describe the principles of their action and efficiency and to summarise the findings from clinical and laboratory studies. Based on previous studies, an appropriate minimum target for moisture output is 30 and 20 g.m⁻³ for long-duration use in intensive care and short-duration use in anaesthesia, respectively. The practice of reusing a breathing system in anaesthesia, provided it is protected by a filter, assumes that the filter is effective. However, there is wide variation in the gas-borne filtration performance, and contaminated condensate can potentially pass through some filters under typical pressures encountered during mechanical ventilation. © 2010 The Author. Anaesthesia © 2010 The Association of Anaesthetists of Great Britain and Ireland.

Respiratory sinus arrhythmia is a limited measure of cardiac parasympathetic control in man.

PubMed Central

Kollai, M; Mizsei, G

1990-01-01

1. Respiratory modulation of cardiac parasympathetic activity and the relationship between respiratory sinus arrhythmia and parasympathetic control has been studied in twenty-nine conscious, healthy young adult subjects. 2. Changes in heart period in propranolol-treated subjects were taken as the measure of changes in cardiac parasympathetic activity; respiratory sinus arrhythmia was quantified as the difference between maximum and minimum heart periods in a given respiratory cycle; cardiac parasympathetic control was defined as the change in heart period after administration of a full dose of atropine. 3. During normal quiet breathing the inspiratory level of cardiac parasympathetic activity was not reduced to zero. The expiratory level was influenced by excitatory inputs whose activation was related to respiratory cycle length. 4. Slow breathing was associated with augmented sinus arrhythmia, but in different individuals the influence on minimum and maximum heart periods varied so that mean heart period was increased in some subjects but decreased in others. This occurred both in control conditions and after administration of a full dose of propranolol. 5. During normal breathing the correlation across subjects between respiratory sinus arrhythmia and parasympathetic control, although significant, was not close (r = 0.61). The relationship was not affected by beta-adrenergic blockade (r = 0.63). The strength of the correlation improved when multiple regression of respiratory sinus arrhythmia was performed on three variables: parasympathetic control, respiratory cycle length and tidal volume (R = 0.93). 6. It is concluded that in conscious human subjects the respiratory modulation of cardiac parasympathetic activity is different from that observed in the anaesthetized dog, and that variations in the amplitude of respiratory sinus arrhythmia do not necessarily reflect proportional changes in cardiac parasympathetic control. PMID:2391653

Study of the motion and deposition of micro particles in a vertical tube containing uniform gas flow

NASA Astrophysics Data System (ADS)

Abolpour, Bahador; Afsahi, M. Mehdi; Soltani Goharrizi, Ataallah; Azizkarimi, Mehdi

2017-12-01

In this study, effects of a gaseous jet, formed in a vertical tube containing a uniform gas flow, on the injected micro particles have been investigated. A CFD model has been developed to simulate the particle motion in the tube. This simulation is very close to the experimental data. The results show that, increasing the flow rate of carrier gas or decreasing the flow rate of surrounding gas increases the effect of gaseous jet and also increases trapping rate of the particles by the tube wall. The minimum and maximum residence times of particles approach together with increasing the size of solid particles. Particles larger than 60 μm have a certain and fixed residence time at different flow rates of the carrier or surrounding gas. About 40 μm particle size has minimal trapping by the tube wall at various experimental conditions.

Application of a stepwise method for analyzing fouling in shell-and-tube exchangers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Prieto, M.M.; Miranda, J.; Sigales, B.

1999-12-01

This article presents the results of the application of a quite simple method for analyzing shell-side fouling in shell-and-tube exchangers, capable of taking into account the formation or irregular fouling deposits with variable thermal conductivity. This method, based on the utilization of elementary heat exchangers, has been implemented for E-shell TEMA-type heat exchangers with two tube passes. Several fouling deposit distributions have been simulated so as to ascertain their effects on the heat transfer rate. These distributions consider that fouling is concentrated in zones where the temperature of the fluids is maximum or minimum.

A compact large-format streak tube for imaging lidar

NASA Astrophysics Data System (ADS)

Hui, Dandan; Luo, Duan; Tian, Liping; Lu, Yu; Chen, Ping; Wang, Junfeng; Sai, Xiaofeng; Wen, Wenlong; Wang, Xing; Xin, Liwei; Zhao, Wei; Tian, Jinshou

2018-04-01

The streak tubes with a large effective photocathode area, large effective phosphor screen area, and high photocathode radiant sensitivity are essential for improving the field of view, depth of field, and detectable range of the multiple-slit streak tube imaging lidar. In this paper, a high spatial resolution, large photocathode area, and compact meshless streak tube with a spherically curved cathode and screen is designed and tested. Its spatial resolution reaches 20 lp/mm over the entire Φ28 mm photocathode working area, and the simulated physical temporal resolution is better than 30 ps. The temporal distortion in our large-format streak tube, which is shown to be a non-negligible factor, has a minimum value as the radius of curvature of the photocathode varies. Furthermore, the photocathode radiant sensitivity and radiant power gain reach 41 mA/W and 18.4 at the wavelength of 550 nm, respectively. Most importantly, the external dimensions of our streak tube are no more than Φ60 mm × 110 mm.

Cryogenic thermal emittance measurements on small-diameter stainless steel tubing

NASA Astrophysics Data System (ADS)

Jahromi, Amir E.; Tuttle, James G.; Canavan, Edgar R.

2017-12-01

The Mid Infrared Instrument aboard the James Webb Space Telescope includes a mechanical cryocooler which cools its detectors to their 6 K operating temperature. The refrigerant flows through several meters of ~2 mm diameter 304L stainless steel tubing, with some sections gold plated, and some not, which are exposed to their environment. An issue of water freezing onto the tube surfaces is mitigated by running a warm gas through the lines to sublimate the frozen water. To model the effect of this process on nearby instruments, an accurate measure of the tube emittance is needed. Previously we reported the absorptance of the gold plated stainless steel tubing as a function of source temperature (i.e. its environment). In this work the thermal emittance of the uncoated tubing is measured as a function of its temperature between 100 and 280 K. These values lead to an accurate prediction of the minimum length of time required to thermally recycle the system. We report the technique and present the results.

Reducing adhesion and agglomeration within a cloud of combustible particles

NASA Technical Reports Server (NTRS)

Ross, Howard D.

1988-01-01

The study of combustible particle clouds inside flame tubes is of fundamental scientific interest as well as a practical concern. Only the suspended concentration is important to the combustion process, so that assurances must be provided that a minimum of particles adheres to the tube wall. This paper demonstrates experimentally the ability to minimize adhesion and agglomeration of acoustically-mixed lycopodium particles within a 5-cm diameter lexan flame tube. The area density of particles (ADP) adhering to the wall of bare lexan tubes was measured at greater than 100 particles/sq mm. The nature of adhesion was found to be clearly electrostatic, with the ADP level aggravated by increased mixing time, vigor, and the concentration of particles. Increases in the conductivity of the air and the tube wall did not affect ADP levels substantially. However, the observed adhesion was reduced to less than 10 p/sq mm when the air was ionized by use of an alpha emitter mounted on the inner walls of the flame tube.

Cryogenic Thermal Emittance Measurements on Small-Diameter Stainless Steel Tubing

NASA Technical Reports Server (NTRS)

Jahromi, Amir E.; Tuttle, James G.; Canavan, Edgar R.

2017-01-01

The Mid Infrared Instrument aboard the James Webb Space Telescope includes a mechanical cryocooler which cools its detectors to their 6 K operating temperature. The refrigerant flows through several meters of 2 mm diameter 304L stainless steel tubing, with some sections gold plated, and some not, which are exposed to their environment. An issue of water freezing onto the tube surfaces is mitigated by running a warm gas through the lines to sublimate the frozen water. To model the effect of this process on nearby instruments, an accurate measure of the tube emittance is needed. Previously we reported the absorptance of the gold plated stainless steel tubing as a function of source temperature (i.e. its environment). In this work the thermal emittance of the uncoated tubing is measured as a function of its temperature between 100 and 280 K. These values lead to an accurate prediction of the minimum length of time required to thermally recycle the system. We report the technique and present the results.

Pulsed electron beam propagation in gases under pressure of 6.6 kPa in drift tube

NASA Astrophysics Data System (ADS)

Kholodnaya, G. E.; Sazonov, R. V.; Ponomarev, D. V.; Remnev, G. E.; Poloskov, A. V.

2017-02-01

This paper presents the results of an investigation of pulsed electron beam transport propagated in a drift tube filled with different gases (He, H2, N2, Ar, SF6, and CO2). The total pressure in the drift tube was 6.6 kPa. The experiments were carried out using a TEA-500 pulsed electron accelerator. The electron beam was propagated in the drift tube composed of two sections equipped with reverse current shunts. Under a pressure of 6.6 kPa, the maximum value of the electron beam charge closed on the walls of the drift tube was recorded when the beam was propagated in hydrogen and carbon dioxide. The minimum value of the electron beam charge closed on the walls of the drift tube was recorded for sulfur hexafluoride. The visualization of the pulsed electron beam energy losses onto the walls of the drift chamber was carried out using radiation-sensitive film.

Cryogenic Thermal Emittance Measurements on Small-Diameter Stainless Steel Tubing

NASA Technical Reports Server (NTRS)

Jahromi, A. E.; Tuttle, J. G.; Canavan, E. R.

2017-01-01

The Mid Infrared Instrument aboard the James Webb Space Telescoep includes a mechanical cryocooler which cools its detectors to their 6 K operating temperature. The refrigerant flows through several meters of approximately 2 mm diameter 304L stainless steel tubing, with some sections gold plated, and some not, which are exposed to their environment. An issue of water freezing onto the tube surfaces is mitigated by a running a warm gas through the lines to sublimate the water. To model the effect of this process on nearby instruments, an accurate measure of the tube emittance is needed. Previously we reported the abosprtance of the gold plated stainless steel tubing as a function of source temperature (i.e. its environment). In this work the thermal emittance of the uncoated tubing is measured as a function of its temperature between 100 and 300 K. This value leads to an accurate prediction of the minimum length of time required to thermally recycle the system. We report the technique and present the results.

First-principles simulations on suspended coinage-metal nanotubes composed of different atomic species.

PubMed

Fa, Wei; Zhou, Jian; Dong, Jinming

2013-04-07

Substitutional doping of gold and copper atoms in a (4, 4) silver single-wall nanotube has been investigated using first-principles simulations. It is found that the Au- and Cu-substitutional doping of the tip-suspended (4, 4) Ag tube can maintain the hollow tubular structure at different alloy compositions due to the existence of a local minimum in the string tension variation with their unit cell lengths. The bonding energy differences between the mono-elements and hetero-elements and string tension may play important roles in suppressing the "self-purification" effects so that the nanoalloy tubes can be formed. Analysis of the band structure suggests that the number of conduction channels of the Ag-Au alloy tubes may lie between the pure (4, 4) Ag and Au tubes.

In Vitro Effect of Zingiber officinale Extract on Growth of Streptococcus mutans and Streptococcus sanguinis.

PubMed

Azizi, Arash; Aghayan, Shabnam; Zaker, Saeed; Shakeri, Mahdieh; Entezari, Navid; Lawaf, Shirin

2015-01-01

Background and Objectives. Tooth decay is an infectious disease of microbial origin. Considering the increasing prevalence of antibiotic resistance due to their overuse and also their side effects, medicinal plants are now considered for use against bacterial infections. This study aimed to assess the effects of different concentrations of Zingiber officinale extract on proliferation of Streptococcus mutans and Streptococcus sanguinis in vitro. Materials and Methods. In this experimental study, serial dilutions of the extract were prepared in two sets of 10 test tubes for each bacterium (total of 20). Standard amounts of bacterial suspension were added; 100ƛ of each tube was cultured on prepared solid agar plates and incubated at 37°C for 24 hours. Serial dilutions of the extract were prepared in another 20 tubes and 100ƛ of each tube was added to blood agar culture medium while being prepared. The mixture was transferred to the plates. The bacteria were inoculated on plates and incubated as described. Results. The minimum inhibitory concentration (MIC) was 0.02 mg/mL for S. mutans and 0.3 mg/mL for S. sanguinis. The minimum bactericidal concentration (MBC) was 0.04 mg for S. mutans and 0.6 mg for S. sanguinis. Conclusion. Zingiber officinale extract has significant antibacterial activity against S. mutans and S. sanguinis cariogenic microorganisms.

In Vitro Effect of Zingiber officinale Extract on Growth of Streptococcus mutans and Streptococcus sanguinis

PubMed Central

Azizi, Arash; Aghayan, Shabnam; Zaker, Saeed; Shakeri, Mahdieh; Entezari, Navid; Lawaf, Shirin

2015-01-01

Background and Objectives. Tooth decay is an infectious disease of microbial origin. Considering the increasing prevalence of antibiotic resistance due to their overuse and also their side effects, medicinal plants are now considered for use against bacterial infections. This study aimed to assess the effects of different concentrations of Zingiber officinale extract on proliferation of Streptococcus mutans and Streptococcus sanguinis in vitro. Materials and Methods. In this experimental study, serial dilutions of the extract were prepared in two sets of 10 test tubes for each bacterium (total of 20). Standard amounts of bacterial suspension were added; 100ƛ of each tube was cultured on prepared solid agar plates and incubated at 37°C for 24 hours. Serial dilutions of the extract were prepared in another 20 tubes and 100ƛ of each tube was added to blood agar culture medium while being prepared. The mixture was transferred to the plates. The bacteria were inoculated on plates and incubated as described. Results. The minimum inhibitory concentration (MIC) was 0.02 mg/mL for S. mutans and 0.3 mg/mL for S. sanguinis. The minimum bactericidal concentration (MBC) was 0.04 mg for S. mutans and 0.6 mg for S. sanguinis. Conclusion. Zingiber officinale extract has significant antibacterial activity against S. mutans and S. sanguinis cariogenic microorganisms. PMID:26347778

Clinical evaluation of stethoscope-guided inflation of tracheal tube cuffs.

PubMed

Kumar, R D C; Hirsch, N P

2011-11-01

Tracheal tube cuffs are commonly inflated to pressures exceeding the recommended upper limit of 30 cmH(2)O. We evaluated whether a stethoscope-guided method of cuff inflation results in pressures within the recommended range. Patients were randomly assigned to receive one of two methods of cuff inflation. In the standard 'just seal' group, air was introduced into the tracheal cuff until the audible leak at the mouth disappeared. In the stethoscope-guided group, air was introduced into the cuff until a change from harsh to soft breath sounds occurred, whilst listening with a stethoscope bell placed over the thyroid cartilage. Twenty-five patients were recruited to each group. The median (IQR [range]) cuff pressure in the 'just seal' group was 34 (28-40 [18-49]) cmH(2)O, and in the stethoscope-guided group was 20 (20-26 [16-28]) cmH(2)O, p < 0.0001. The stethoscope-guided method of tracheal tube cuff inflation is a novel, simple technique that reliably results in acceptable tracheal cuff pressures. © 2011 The Authors. Anaesthesia © 2011 The Association of Anaesthetists of Great Britain and Ireland.

Application of ion chemistry and the SIFT technique to the quantitative analysis of trace gases in air and on breath

NASA Astrophysics Data System (ADS)

Smith, David; Španěl, Patrik

Our major objective in this paper is to describe a new method we have developed for the analysis of trace gases at partial pressures down to the ppb level in atmospheric air, with special emphasis on the detection and quantification of trace gases on human breath. It involves the use of our selected ion flow tube (Sift) technique which we previously developed and used extensively for the study of gas phase ionic reactions occurring in ionized media such as the terrestrial atmosphere and interstellar gas clouds. Before discussing this analytical technique we describe the results of our very recent Sift and flowing afterglow (FA) studies of the reactions of the H3O+ and OH- ions, of their hydrates H3O+(H2O)1,2,3 and OH- (H2O)1,2, and of NO+ and O2+, with several hydrocarbons and oxygen-bearing organic molecules, studies that are very relevant to our trace gas analytical studies. Then follows a detailed discussion of the application of our Sift technique to trace gas analysis, after which we present some results obtained for the analyses of laboratory air, the breath of a healthy non-smoking person, the breath of a person who regularly smokes cigarettes, the complex vapours emitted by banana and onion, and the molecules present in a butane/air flame. We show how the quantitative analysis of breath can be achieved from only a single exhalation and in real time (the time response of the instrument is only about 20 ms). We also show how the time variation of breath gases over long time periods can be followed, using the decay of ethanol on the breath after the ingestion of distilled liquor as an example, yet simultaneously following several other trace gases including acetone and isoprene which are very easily detected on the breath of all individuals because of their relatively high partial pressures (typically 100 to 1000 ppb). The breath of a smoker is richer in complex molecules, some nitrogen containing organics apparently being very evident at the 5 to 50 ppb level. These results and those for banana and onion vapours and butane/air flame forcibly demonstrate the value and the scope of our Sift ion chemistry approach to the analysis of very complex gas mixtures, and that this method is accurately quantitative if the appropriate ion chemistry is properly understood.

MO-DE-207A-12: Toward Patient-Specific 4DCT Reconstruction Using Adaptive Velocity Binning

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morris, E.D.; Glide-Hurst, C.; Wayne State University, Detroit, MI

2016-06-15

Purpose: While 4DCT provides organ/tumor motion information, it often samples data over 10–20 breathing cycles. For patients presenting with compromised pulmonary function, breathing patterns can change over the acquisition time, potentially leading to tumor delineation discrepancies. This work introduces a novel adaptive velocity-modulated binning (AVB) 4DCT algorithm that modulates the reconstruction based on the respiratory waveform, yielding a patient-specific 4DCT solution. Methods: AVB was implemented in a research reconstruction configuration. After filtering the respiratory waveform, the algorithm examines neighboring data to a phase reconstruction point and the temporal gate is widened until the difference between the reconstruction point and waveformmore » exceeds a threshold value—defined as percent difference between maximum/minimum waveform amplitude. The algorithm only impacts reconstruction if the gate width exceeds a set minimum temporal width required for accurate reconstruction. A sensitivity experiment of threshold values (0.5, 1, 5, 10, and 12%) was conducted to examine the interplay between threshold, signal to noise ratio (SNR), and image sharpness for phantom and several patient 4DCT cases using ten-phase reconstructions. Individual phase reconstructions were examined. Subtraction images and regions of interest were compared to quantify changes in SNR. Results: AVB increased signal in reconstructed 4DCT slices for respiratory waveforms that met the prescribed criteria. For the end-exhale phases, where the respiratory velocity is low, patient data revealed a threshold of 0.5% demonstrated increased SNR in the AVB reconstructions. For intermediate breathing phases, threshold values were required to be >10% to notice appreciable changes in CT intensity with AVB. AVB reconstructions exhibited appreciably higher SNR and reduced noise in regions of interest that were photon deprived such as the liver. Conclusion: We demonstrated that patient-specific velocity-based 4DCT reconstruction is feasible. Image noise was reduced with AVB, suggesting potential applications for low-dose acquisitions and to improve 4DCT reconstruction for irregular breathing patients. The submitting institution holds research agreements with Philips Healthcare.« less

Characterization of Carbon Dioxide Washout Measurement Techniques in the Mark-III Space Suit

NASA Technical Reports Server (NTRS)

Norcross, J.; Bekdash, O.; Meginnis, I.

2016-01-01

Providing adequate carbon dioxide (CO2) washout is essential to the reduction of risk in performing suited operations. Long term CO2 exposure can lead to symptoms such as headache, lethargy, dizziness, and in severe cases can lead to unconsciousness and death. Thus maintaining adequate CO2 washout in both ground testing and during in flight EVAs is a requirement of current and future suit designs. It is necessary to understand the inspired CO2 of suit wearers such that future requirements for space suits appropriately address the risk of inadequate washout. Testing conducted by the EVA Physiology Laboratory at the NASA Johnson Space Center aimed to characterize a method for noninvasively measuring inspired oronasal CO2 under pressurized suited conditions in order to better inform requirements definition and verification techniques for future CO2 washout limits in space suits. Prior work conducted by the EPL examined several different wearable, respirator style, masks that could be used to sample air from the vicinity surround the nose and mouth of a suited test subject. Previously published studies utilized these masks, some being commercial products and some novel designs, to monitor CO2 under various exercise and flow conditions with mixed results for repeatability and/or consistency between subjects. Based on a meta-analysis of those studies it was decided to test a nasal cannula as it is a commercially available device that is placed directly in the flow path of the user as they breathe. A nasal cannula was used to sample air inhaled by the test subjects during both rest and exercise conditions. Eight subjects were tasked with walking on a treadmill or operating an arm ergometer to reach target metabolic rates of 1000, 2000, and 3000 BTU/hr. Suit pressure was maintained at 4.3 psid for all tests, with supply flow rates of 6, 4, and 2 actual cubic feet per minute depending on the test condition. Each test configuration was conducted twice with subjects breathing either through their nose only, or however they felt comfortable. By restricting breathing through a single orifice, we are able to more accurately define exactly what flow stream the sampled CO2 is taken from. Oronasal CO2 was monitored using real time infrared gas analyzers fed via sample tubes connected to the nasal cannula within the suit. Two additional sampling tubes were placed at the head and chin of the test subject, in an effort to capture CO2 concentrations across the entire flow stream of the Mark-III vent system (flow path is head to neck). Metabolic rate was calculated via the exhaust CO2 concentration and used to adjust subject workload on either the treadmill or arm ergometer until the target was reached. Forward work will aim to characterize the historically accepted minimum ppCO2 in suit during EVA by repeating this study in the Extravehicular Mobility Unit (EMU) space suit. This will help to define washout requirements for future suits, be they NASA (e.g. Z-2) or Commercial Crew designed. Additionally it is important to determine the functional consequences of CO2 exposure during EVA. Severe CO2 symptoms are a result of very high concentration, acute exposures. While long term, low concentration exposures have been shown to result in slight cognitive decline, symptoms resolve upon quickly returning to nominal concentrations and it remains unknown the impact that minor deficits in cognitive performance can have on EVA performance.

Robust Adaptive Flight Control Design of Air-breathing Hypersonic Vehicles

DTIC Science & Technology

2016-12-07

dynamic inversion controller design for a non -minimum phase hypersonic vehicle is derived by Kuipers et al. [2008]. Moreover, integrated guidance and...stabilization time for inner loop variables is lesser than the intermediate loop variables because of the three-loop-control design methodology . The control...adaptive design . Control Engineering Practice, 2016. Michael A Bolender and David B Doman. A non -linear model for the longitudinal dynamics of a

Increased risk of Eustachian tube disorders in patients with sleep-disordered breathing.

PubMed

Chou, Meng-Shih; Chang, Wen-Dien; Lin, Che-Chen; Li, Yu-Fen; Tsou, Yung-An

2017-08-01

Sleep-disordered breathing (SDB) and Eustachian tube disorders (ETDs) share the same risk factors. The specific aim of this study was to determine the correlation between these 2 conditions and to determine whether treatments for SDB reduce the risk of ETD.This is a retrospective and large population-based cohort study. According to Taiwan's National Health Insurance Research Database, out of 1,000,000 insured patients, 24,251 patients were newly diagnosed with SDB from year 2000 through 2009. The control group for this study comprised 96,827 patients without SDB who were randomly selected from the same database at a ratio of 1:4, frequency matched for sex, age, and index year of SDB. The incidence of developing ETD was compared between these 2 groups; the main covariates were demographic data, interventions, and medical comorbidities.There was an increased risk of developing ETD among the SDB cohort compared with the control group (hazard ratio = 1.51, 95% confidence interval = 1.41-1.63). Compared with SDB patients who did not receive treatment, those who received the treatment, that is, pharyngeal or nasal surgery, CPAP, or multiple modalities (both surgery and CPAP), had a significantly reduced risk of developing ETD.This study showed that patients with SDB are at an increased risk of developing ETD and other comorbidities. The risk of developing ETD can be reduced by implementing prompt treatment for SDB. Multidisciplinary evaluation including ETD should be conducted in the management of patients presenting with SDB.

Radiostethoscopes: an innovative solution for auscultation while wearing protective gear.

PubMed

Candiotti, Keith A; Rodriguez, Yiliam; Curia, Luciana; Saltzman, Bruce; Shekhter, Ilya; Rosen, Lisa; Birnbach, David J

2011-01-01

To demonstrate a radiostethoscope that could be modified and successfully used while wearing protective gear to solve the problem of auscultation in a hazardous material or infectious disease setting. This study was a randomized, prospective, and blinded investigation. The study was conducted at the University of Miami-Jackson Memorial Hospital Center for Patient Safety. Two blinded anesthesiologists using a radiostethoscope performed a total of 100 assessments (50 each) to evaluate endotracheal tube position on a human patient simulator (HPS). Each lung of the HPS was ventilated separately using a double lumen tube. Four ventilation patterns (ie, right lung ventilation only; left lung ventilation only; ventilation of both lungs; and an esophageal intubation or no breath sounds) were simulated. The ventilation pattern was determined randomly and participants were blinded. An Ambu-Bag was used for ventilation. An assistant moved the radiostethoscope to the right and left lung fields and then to the abdomen of the HPS while ventilating. Subjects had to identify the ventilation pattern after listening to all three locations. A third member of the research team collected responses. Each subject, who wore both types of respirator (positive and negative), performed a total of 25 trials. Participants later compared the two types of respirators and their ability to auscultate for breath sounds. Subjects were able to verify the correct ventilation pattern in all attempts (100 percent). Radiostethoscopes appear to provide a viable solution for the problem of patient auscultation while wearing protective gear.

Filters Reduce the Risk of Bacterial Transmission from Contaminated Heated Humidifiers Used with CPAP for Obstructive Sleep Apnea

PubMed Central

Ortolano, Girolamo A.; Schaffer, Jeffrey; McAlister, Morven B.; Stanchfield, Ilia; Hill, Elizabeth; Vandenburgh, Liliana; Lewis, Michelle; John, Shirnett; Canonica, Francis P.; Cervia, Joseph S.

2007-01-01

Rationale: The treatment of choice for obstructive sleep apnea (OSA) is nasal continuous positive airway pressure (nCPAP) during sleep, but dryness of the upper airway compromises compliance. Heated humidifiers may mitigate such noncompliance; however, recent observations suggest that their use, particularly if not cleaned, increases the risk of respiratory infections. Humidifier water may be contaminated, but the long-held view that passive humidifiers cannot aerosolize water may obscure the perception of risk of infection. Objectives: This study challenges the long-held view that “passover” humidifiers do not aerosolize water. With such evidence, this study characterizes the performance of filters to reduce the potential risk of contamination. Methods: Heated humidifier water contaminated with bacteria was studied under conditions simulating week-long use of nCPAP for OSA. Results: Bacteria were recovered in 9 of 11 tests from the breathing tubes of CPAP devices fitted with heated humidifiers with water contaminated with Brevundimonas diminuta or Serratia marcescens. Recoverable bacteria ranged from tens to thousands of colony forming units when tested at air flow rates of 60 liters per minute for 90 minutes. Neither organism was recovered from the circuit tubing when a hydrophobic breathing-circuit filter was positioned between the humidifier and face-mask tubing with a commercially available nCPAP machine tested under simulated-use conditions. Conclusion: Data suggest that patients with OSA being treated with nCPAP fitted with humidifiers may be aerosolizing bacteria, putting them at risk for developing respiratory infections and that the use of a hydrophobic filter may attenuate the passage of microbes from contaminated humidifier water. Citation: Ortolano GA; Schaffer J; McAlister MB et al. Filters reduce the risk of bacterial transmission from contaminated heated humidifiers used with CPAP for obstructive sleep apnea. J Clin Sleep Med 2007;3(7):700–705. PMID:18198803

Breath Analysis as a Potential and Non-Invasive Frontier in Disease Diagnosis: An Overview

PubMed Central

Pereira, Jorge; Porto-Figueira, Priscilla; Cavaco, Carina; Taunk, Khushman; Rapole, Srikanth; Dhakne, Rahul; Nagarajaram, Hampapathalu; Câmara, José S.

2015-01-01

Currently, a small number of diseases, particularly cardiovascular (CVDs), oncologic (ODs), neurodegenerative (NDDs), chronic respiratory diseases, as well as diabetes, form a severe burden to most of the countries worldwide. Hence, there is an urgent need for development of efficient diagnostic tools, particularly those enabling reliable detection of diseases, at their early stages, preferably using non-invasive approaches. Breath analysis is a non-invasive approach relying only on the characterisation of volatile composition of the exhaled breath (EB) that in turn reflects the volatile composition of the bloodstream and airways and therefore the status and condition of the whole organism metabolism. Advanced sampling procedures (solid-phase and needle traps microextraction) coupled with modern analytical technologies (proton transfer reaction mass spectrometry, selected ion flow tube mass spectrometry, ion mobility spectrometry, e-noses, etc.) allow the characterisation of EB composition to an unprecedented level. However, a key challenge in EB analysis is the proper statistical analysis and interpretation of the large and heterogeneous datasets obtained from EB research. There is no standard statistical framework/protocol yet available in literature that can be used for EB data analysis towards discovery of biomarkers for use in a typical clinical setup. Nevertheless, EB analysis has immense potential towards development of biomarkers for the early disease diagnosis of diseases. PMID:25584743

Breath analysis as a potential and non-invasive frontier in disease diagnosis: an overview.

PubMed

Pereira, Jorge; Porto-Figueira, Priscilla; Cavaco, Carina; Taunk, Khushman; Rapole, Srikanth; Dhakne, Rahul; Nagarajaram, Hampapathalu; Câmara, José S

2015-01-09

Currently, a small number of diseases, particularly cardiovascular (CVDs), oncologic (ODs), neurodegenerative (NDDs), chronic respiratory diseases, as well as diabetes, form a severe burden to most of the countries worldwide. Hence, there is an urgent need for development of efficient diagnostic tools, particularly those enabling reliable detection of diseases, at their early stages, preferably using non-invasive approaches. Breath analysis is a non-invasive approach relying only on the characterisation of volatile composition of the exhaled breath (EB) that in turn reflects the volatile composition of the bloodstream and airways and therefore the status and condition of the whole organism metabolism. Advanced sampling procedures (solid-phase and needle traps microextraction) coupled with modern analytical technologies (proton transfer reaction mass spectrometry, selected ion flow tube mass spectrometry, ion mobility spectrometry, e-noses, etc.) allow the characterisation of EB composition to an unprecedented level. However, a key challenge in EB analysis is the proper statistical analysis and interpretation of the large and heterogeneous datasets obtained from EB research. There is no standard statistical framework/protocol yet available in literature that can be used for EB data analysis towards discovery of biomarkers for use in a typical clinical setup. Nevertheless, EB analysis has immense potential towards development of biomarkers for the early disease diagnosis of diseases.

Fabrication of Aluminum Tubes Filled with Aluminum Alloy Foam by Friction Welding

PubMed Central

Hangai, Yoshihiko; Nakano, Yukiko; Koyama, Shinji; Kuwazuru, Osamu; Kitahara, Soichiro; Yoshikawa, Nobuhiro

2015-01-01

Aluminum foam is usually used as the core of composite materials by combining it with dense materials, such as in Al foam core sandwich panels and Al-foam-filled tubes, owing to its low tensile and bending strengths. In this study, all-Al foam-filled tubes consisting of ADC12 Al-Si-Cu die-cast aluminum alloy foam and a dense A1050 commercially pure Al tube with metal bonding were fabricated by friction welding. First, it was found that the ADC12 precursor was firmly bonded throughout the inner wall of the A1050 tube without a gap between the precursor and the tube by friction welding. No deformation of the tube or foaming of the precursor was observed during the friction welding. Next, it was shown that by heat treatment of an ADC12-precursor-bonded A1050 tube, gases generated by the decomposition of the blowing agent expand the softened ADC12 to produce the ADC12 foam interior of the dense A1050 tube. A holding time during the foaming process of approximately tH = 8.5 min with a holding temperature of 948 K was found to be suitable for obtaining a sound ADC12-foam-filled A1050 tube with sufficient foaming, almost uniform pore structures over the entire specimen, and no deformation and minimum reduction in the thickness of the tube. PMID:28793629

Evaluation of the dependence of the exposure dose on the attenuation correction in brain PET/CT scans using 18F-FDG

NASA Astrophysics Data System (ADS)

Choi, Eun-Jin; Jeong, Moon-Taeg; Jang, Seong-Joo; Choi, Nam-Gil; Han, Jae-Bok; Yang, Nam-Hee; Dong, Kyung-Rae; Chung, Woon-Kwan; Lee, Yun-Jong; Ryu, Young-Hwan; Choi, Sung-Hyun; Seong, Kyeong-Jeong

2014-01-01

This study examined whether scanning could be performed with minimum dose and minimum exposure to the patient after an attenuation correction. A Hoffman 3D Brain Phantom was used in BIO_40 and D_690 PET/CT scanners, and the CT dose for the equipment was classified as a low dose (minimum dose), medium dose (general dose for scanning) and high dose (dose with use of contrast medium) before obtaining the image at a fixed kilo-voltage-peak (kVp) and milliampere (mA) that were adjusted gradually in 17-20 stages. A PET image was then obtained to perform an attenuation correction based on an attenuation map before analyzing the dose difference. Depending on tube current in the range of 33-190 milliampere-second (mAs) when BIO_40 was used, a significant difference in the effective dose was observed between the minimum and the maximum mAs (p < 0.05). According to a Scheffe post-hoc test, the ratio of the minimum to the maximum of the effective dose was increased by approximately 5.26-fold. Depending on the change in the tube current in the range of 10-200 mA when D_690 was used, a significant difference in the effective dose was observed between the minimum and the maximum of mA (p < 0.05). The Scheffe posthoc test revealed a 20.5-fold difference. In conclusion, because effective exposure dose increases with increasing operating current, it is possible to reduce the exposure limit in a brain scan can be reduced if the CT dose can be minimized for a transmission scan.

Demonstration and Validation of a Regenerated Cellulose Dialysis Membrane Diffusion Sampler for Monitoring Ground Water Quality and Remediation Progress at DoD Sites for Perchlorate and Explosives Compounds

DTIC Science & Technology

2010-09-01

Regulatory Council LRL Laboratory reporting level LDPE Low-density polyethylene MDL Minimum detection limit MNA Monitored natural attenuation...consists of a tubular-shaped bag made of flexible low-density polyethylene ( LDPE ) (Vroblesky, 2001a, 2001b). The LDPE tube is heat-sealed on one end...be constructed from small- diameter LDPE tubing that fits into small-diameter wells. These polyethylene diffusion bag (PDB) samplers have been

Demonstration and Validation of a Regenerated Cellulose Dialysis Membrane Diffusion Sampler for Monitoring Ground-Water Quality and Remediation Progress at DoD Site: Perchlorate and Ordnance Compounds

DTIC Science & Technology

2011-10-01

Regulatory Council LDPE low-density polyethylene MDL minimum detection limit NAVFAC ESC Naval Facilities Engineering Command Engineering Service...membrane sampler design consists of a tubular-shaped bag made of flexible low-density polyethylene ( LDPE ) (Vroblesky, 2001a, 2001b). The LDPE tube is...requirements, and can be constructed from small-diameter LDPE tubing that fits into small- 4 diameter wells. These polyethylene diffusion bag

Demonstration and Validation of a Regenerated Cellulose Dialysis Membrane Diffusion Sampler for Monitoring Ground-Water Quality and Remediation Progress at DoD Sites

DTIC Science & Technology

2010-04-01

LDPE low-density polyethylene LF low-flow purging LRL laboratory reporting level MDL minimum detection limit MNA monitored natural attenuation...shaped bag made of flexible low-density polyethylene ( LDPE ) (Vroblesky, 2001a, 2001b). The LDPE tube is heat-sealed on one end, filled with high...from small- diameter LDPE tubing that fits into small-diameter wells. These PDB samplers have been shown to be useful only for collection of VOCs

Numerical Design of Megawatt Gyrotron with 120 GHz Frequency and 50% Efficiency for Plasma Fusion Application

NASA Astrophysics Data System (ADS)

Kumar, Nitin; Singh, Udaybir; Kumar, Anil; Bhattacharya, Ranajoy; Singh, T. P.; Sinha, A. K.

2013-02-01

The design of 120 GHz, 1 MW gyrotron for plasma fusion application is presented in this paper. The mode selection is carried out considering the aim of minimum mode competition, minimum cavity wall heating, etc. On the basis of the selected operating mode, the interaction cavity design and beam-wave interaction computation are carried out by using the PIC code. The design of triode type Magnetron Injection Gun (MIG) is also presented. Trajectory code EGUN, synthesis code MIGSYN and data analysis code MIGANS are used in the MIG designing. Further, the design of MIG is also validated by using the another trajectory code TRAK. The design results of beam dumping system (collector) and RF window are also presented. Depressed collector is designed to enhance the overall tube efficiency. The design study confirms >1 MW output power with tube efficiency around 50% (with collector efficiency).

Treatment of displaced intra-articular calcaneal fractures with triangular tube-to-bar external fixation: long-term clinical follow-up and radiographic analysis.

PubMed

Roukis, Thomas S; Wünschel, Markus; Lutz, Hans-Peter; Kirschner, Peter; Zgonis, Thomas

2008-04-01

Sixty-six feet (62 patients) with displaced intra-articular calcaneal fractures underwent manual reduction and distraction with the use of a triangular tube-to-bar external fixation device and were retrospectively reviewed at a minimum of 1-year post-operative. Final radiographic follow-up revealed complete consolidation in all fractures, maintenance of reduction, and limited degenerative osteoarthrosis about the subtalar joint. Our results indicate that with proper application and attention to detail, restoration of calcaneal morphology using triangular tube-to-bar external fixation should be considered a viable alternative in the treatment of displaced intra-articular fractures of the calcaneus.

Determination of ethane, pentane and isoprene in exhaled air--effects of breath-holding, flow rate and purified air.

PubMed

Lärstad, M A E; Torén, K; Bake, B; Olin, A-C

2007-01-01

Exhaled ethane, pentane and isoprene have been proposed as biomarkers of oxidative stress. The objectives were to explore whether ethane, pentane and isoprene are produced within the airways and to explore the effect of different sampling parameters on analyte concentrations. The flow dependency of the analyte concentrations, the concentrations in dead-space and alveolar air after breath-holding and the influence of inhaling purified air on analyte concentrations were investigated. The analytical method involved thermal desorption from sorbent tubes and gas chromatography. The studied group comprised 13 subjects with clinically stable asthma and 14 healthy controls. Ethane concentrations decreased slightly, but significantly, at higher flow rates in subjects with asthma (P = 0.0063) but not in healthy controls. Pentane levels were increased at higher flow rates both in healthy and asthmatic subjects (P = 0.022 and 0.0063 respectively). Isoprene levels were increased at higher flow rates, but only significantly in healthy subjects (P = 0.0034). After breath-holding, no significant changes in ethane levels were observed. Pentane and isoprene levels increased significantly after 20 s of breath-holding. Inhalation of purified air before exhalation resulted in a substantial decrease in ethane levels, a moderate decrease in pentane levels and an increase in isoprene levels. The major fractions of exhaled ethane, pentane and isoprene seem to be of systemic origin. There was, however, a tendency for ethane to be flow rate dependent in asthmatic subjects, although to a very limited extent, suggesting that small amounts of ethane may be formed in the airways.

Increase of methanol in exhaled breath quantified by SIFT-MS following aspartame ingestion.

PubMed

Španěl, Patrik; Dryahina, Kseniya; Vicherková, Petra; Smith, David

2015-11-19

Aspartame, methyl-L-α-aspartyl-L-phenylalaninate, is used worldwide as a sweetener in foods and drinks and is considered to be safe at an acceptable daily intake (ADI) of 40 mg per kg of body weight. This compound is completely hydrolyzed in the gastrointestinal tract to aspartic acid, phenylalanine and methanol, each being toxic at high levels. The objective of the present study was to quantify the volatile methanol component in the exhaled breath of ten healthy volunteers following the ingestion of a single ADI dose of aspartame. Direct on-line measurements of methanol concentration were made in the mouth and nose breath exhalations using selected ion flow tube mass spectrometry, SIFT-MS, several times before aspartame ingestion in order to establish individual pre-dose (baseline) levels and then during two hours post-ingestion to track their initial increase and subsequent decrease. The results show that breath methanol concentrations increased in all volunteers by 1082   ±   205 parts-per-billion by volume (ppbv) from their pre-ingestion values, which ranged from 193 to 436 ppbv to peak values ranging from 981-1622 ppbv, from which they slowly decreased. These observations agree quantitatively with a predicted increase of 1030 ppbv estimated using a one-compartment model of uniform dilution of the methanol generated from a known amount of aspartame throughout the total body water (including blood). In summary, an ADI dose of aspartame leads to a 3-6 fold increase of blood methanol concentration above the individual baseline values.

Weaning from mechanical ventilation: why are we still looking for alternative methods?

PubMed

Frutos-Vivar, F; Esteban, A

2013-12-01

Most patients who require mechanical ventilation for longer than 24 hours, and who improve the condition leading to the indication of ventilatory support, can be weaned after passing a first spontaneous breathing test. The challenge is to improve the weaning of patients who fail that first test. We have methods that can be referred to as traditional, such as the T-tube, pressure support or synchronized intermittent mandatory ventilation (SIMV). In recent years, however, new applications of usual techniques as noninvasive ventilation, new ventilation methods such as automatic tube compensation (ATC), mandatory minute ventilation (MMV), adaptive support ventilation or automatic weaning systems based on pressure support have been described. Their possible role in weaning from mechanical ventilation among patients with difficult or prolonged weaning remains to be established. Copyright © 2012 Elsevier España, S.L. and SEMICYUC. All rights reserved.

Design of a Minimum Surface-Effect Three Degree-of-Freedom Micromanipulator

NASA Technical Reports Server (NTRS)

Goldfarb, Michael; Speich, John E.

1997-01-01

This paper describes the fundamental physical motivations for small-scale minimum surface-effect design, and presents a three degree-of-freedom micromanipulator design that incorporates a minimum surface-effect approach. The primary focus of the design is the split-tube flexure, a unique small-scale revolute joint that exhibits a considerably larger range of motion and significantly better multi-axis revolute joint characteristics than a conventional flexure. The development of this joint enables the implementation of a small-scale spatially-loaded revolute joint-based manipulator with well-behaved kinematic characteristics and without the backlash and stick-slip behavior that would otherwise prevent precision control

A case report of a spontaneous oesophageal pleural fistula.

PubMed

Kumar, Sanjeev; Singh, Arshdeep; Matreja, Prithpal S; Kler, Sanjiv Kumar

2013-03-01

We are reporting a case of an asthmatic patient who presented to us with retrosternal chest pain, constipation, and shortness of breath, with features which were suggestive of a hydropneumothorax and shock. On recovery from the shock, the patient was found to have increased chest tube drainage, which was suggestive of an oesophageal rupture. The Computerized Tomography (CT) scan showed a fistulous track. The patient was diagnosed as a case of a spontaneous oesophageal pleural fistula (Spontaneous EPF) on the basis of her clinical and radiological findings.

A Case Report of a Spontaneous Oesophageal Pleural Fistula

PubMed Central

Kumar, Sanjeev; Singh, Arshdeep; Matreja, Prithpal S; Kler, Sanjiv Kumar

2013-01-01

We are reporting a case of an asthmatic patient who presented to us with retrosternal chest pain, constipation, and shortness of breath, with features which were suggestive of a hydropneumothorax and shock. On recovery from the shock, the patient was found to have increased chest tube drainage, which was suggestive of an oesophageal rupture. The Computerized Tomography (CT) scan showed a fistulous track. The patient was diagnosed as a case of a spontaneous oesophageal pleural fistula (Spontaneous EPF) on the basis of her clinical and radiological findings. PMID:23634410

Association of Pulmonary Cysts and Nodules in a Young Female Patient.

PubMed

Dias, Olívia Meira; do Nascimento, Ellen Caroline Toledo; Carvalho, Carlos Roberto Ribeiro; Araujo, Mariana Sponholz; Freitas, Carolina Salim Gonçalves; Kairalla, Ronaldo Adib; Dolhnikoff, Marisa; Baldi, Bruno Guedes

2016-06-01

A 27-year-old female patient was referred to our outpatient clinic with a 1-year history of shortness of breath when walking fast on level ground or when climbing stairs. Symptoms worsened after a second episode of spontaneous left pneumothorax, when a chest tube was placed in another hospital for complete lung expansion. During this hospitalization, an open lung biopsy was performed. There was no history of rhinorrhea, nasal congestion, cough, hemoptysis, wheezing, or expectoration. Copyright © 2016 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.

GSTARS computer models and their applications, part I: theoretical development

USGS Publications Warehouse

Yang, C.T.; Simoes, F.J.M.

2008-01-01

GSTARS is a series of computer models developed by the U.S. Bureau of Reclamation for alluvial river and reservoir sedimentation studies while the authors were employed by that agency. The first version of GSTARS was released in 1986 using Fortran IV for mainframe computers. GSTARS 2.0 was released in 1998 for personal computer application with most of the code in the original GSTARS revised, improved, and expanded using Fortran IV/77. GSTARS 2.1 is an improved and revised GSTARS 2.0 with graphical user interface. The unique features of all GSTARS models are the conjunctive use of the stream tube concept and of the minimum stream power theory. The application of minimum stream power theory allows the determination of optimum channel geometry with variable channel width and cross-sectional shape. The use of the stream tube concept enables the simulation of river hydraulics using one-dimensional numerical solutions to obtain a semi-two- dimensional presentation of the hydraulic conditions along and across an alluvial channel. According to the stream tube concept, no water or sediment particles can cross the walls of stream tubes, which is valid for many natural rivers. At and near sharp bends, however, sediment particles may cross the boundaries of stream tubes. GSTARS3, based on FORTRAN 90/95, addresses this phenomenon and further expands the capabilities of GSTARS 2.1 for cohesive and non-cohesive sediment transport in rivers and reservoirs. This paper presents the concepts, methods, and techniques used to develop the GSTARS series of computer models, especially GSTARS3. ?? 2008 International Research and Training Centre on Erosion and Sedimentation and the World Association for Sedimentation and Erosion Research.

Design and development of multipurpose Kundt’s tube as physics learning media

NASA Astrophysics Data System (ADS)

Nursulistiyo, E.

2018-03-01

Research had been conducted to develop Multipurpose Kundt's tube as a physics learning media. Research background was the absence of sound waves visualization to improve the understanding of learners. The purposes of this research were to develop Multipurpose Kundt’s tube as physics learning media and to test its feasibility. The developed tool was tested to find the speed of sound in the air, showing the double slit interference phenomenon of the sound, and show the temperature changes in the cold and heat reservoirs in the thermoacoustic process. The development step that had been used was Preliminary Study, Development, Field Test, and Dissemination or known as PDFD Model. On the implementation, the dissemination process was not done. The test was done by the experts, peers, and college students to find out the media feasibility level. The speed of sound in the air which was measured using Multipurpose Kundt’s tube obtained v ± Δv = 263 ± 24 m/s with the closeness value of 76.63% closer to the theoretical value. Also, it was founded a calibration factor of 1.32. The tool was able to show sound waves on the open-end tube. The value of the distance between minimum and maximum interferences between the experimental results compared to theory was almost the same, so it was concluded that the phenomenon of double-slit interference of the sound could be shown by the tool. The thermoacoustic phenomenon could be observed and gave maximum temperature 31.4°C in the hot reservoir, and minimum temperature 24°C in the cold reservoir at the frequency of 119 Hz. Temperature differences obtained 7.4°C. The result of the feasibility test obtained the average result of 88.23 in a “Very Good” category.

The Role of Incentive Spirometry in Primary Spontaneous Pneumothorax.

PubMed

Pribadi, Rabbinu R; Singh, Gurmeet; Rumende, Cleopas M

2016-01-01

Pneumothorax is the presence of air in the pleural space. Its management consists of noninvasive and invasive therapies and it is determined based on clinical manifestations, type and size of pneumothorax. We present a case of a patient with diagnosis of primary spontaneous pneumothorax treated with incentive spirometry (noninvasive therapy). A 20 year old man came to respirology clinic with chief complaint of shortness of breath. He was recently diagnosed with left pneumothorax based on previous chest X-ray in another health care facilities and was advised to undergo tube thoracostomy but he refused the procedure. On physical examination, vital signs were normal. Chest X-ray showed 33% of pneumothorax or 1.2 cm. He was asked to perform incentive spirometry therapy at home. During 12 days of therapy, shortness of breath slowly disappeared and on repeated chest X-ray, it showed minimal pneumothorax in the left upper hemithorax. Noninvasive treatment such as incentive spirometry can be considered in patient with minimal symptoms and no signs of life-threatening respiratory distress.

Non-intubated uniportal left-lower lobe upper segmentectomy (S6)

PubMed Central

Navarro-Martinez, Jose; Bolufer, Sergio; Sesma, Julio; Lirio, Francisco; Galiana, Maria; Rivera, Maria Jesus

2017-01-01

Worldwide accepted indications of anatomical segmentectomies are mainly early stage primary adenocarcinomas, pulmonary metastasis and benign conditions. Their performance through uniportal VATS has become more and more popular due to the less invasiveness of the whole procedure under this approach. Recently, many efforts have focused on non-intubated spontaneously breathing management of lobectomies and anatomical segmentectomies, although specific selection criteria and main advantages are not completely standardized. In a 62-year-old thin man with two pulmonary residual metastasis from sigma adenocarcinoma, after chemotherapy plus antiangiogenic treatment, we indicated a single-incision video-assisted left-lower lobe (LLL) upper segmentectomy (S6) under spontaneous breathing and intercostal blockade. Total operation time was 240 minutes. Chest tube was removed at 24 hours and the patient was discharge on postoperative day 2 without any complication. Non-intubated uniportal VATS is a safe and reasonable approach for lung-sparing resections in selected patients, although more evidence is required for selecting which patients can benefit more over standard intubated procedures. PMID:29078611

Non-intubated uniportal left-lower lobe upper segmentectomy (S6).

PubMed

Galvez, Carlos; Navarro-Martinez, Jose; Bolufer, Sergio; Sesma, Julio; Lirio, Francisco; Galiana, Maria; Rivera, Maria Jesus

2017-01-01

Worldwide accepted indications of anatomical segmentectomies are mainly early stage primary adenocarcinomas, pulmonary metastasis and benign conditions. Their performance through uniportal VATS has become more and more popular due to the less invasiveness of the whole procedure under this approach. Recently, many efforts have focused on non-intubated spontaneously breathing management of lobectomies and anatomical segmentectomies, although specific selection criteria and main advantages are not completely standardized. In a 62-year-old thin man with two pulmonary residual metastasis from sigma adenocarcinoma, after chemotherapy plus antiangiogenic treatment, we indicated a single-incision video-assisted left-lower lobe (LLL) upper segmentectomy (S6) under spontaneous breathing and intercostal blockade. Total operation time was 240 minutes. Chest tube was removed at 24 hours and the patient was discharge on postoperative day 2 without any complication. Non-intubated uniportal VATS is a safe and reasonable approach for lung-sparing resections in selected patients, although more evidence is required for selecting which patients can benefit more over standard intubated procedures.

The Caenorhabditis elegans Excretory System: A Model for Tubulogenesis, Cell Fate Specification, and Plasticity

PubMed Central

Sundaram, Meera V.; Buechner, Matthew

2016-01-01

The excretory system of the nematode Caenorhabditis elegans is a superb model of tubular organogenesis involving a minimum of cells. The system consists of just three unicellular tubes (canal, duct, and pore), a secretory gland, and two associated neurons. Just as in more complex organs, cells of the excretory system must first adopt specific identities and then coordinate diverse processes to form tubes of appropriate topology, shape, connectivity, and physiological function. The unicellular topology of excretory tubes, their varied and sometimes complex shapes, and the dynamic reprogramming of cell identity and remodeling of tube connectivity that occur during larval development are particularly fascinating features of this organ. The physiological roles of the excretory system in osmoregulation and other aspects of the animal’s life cycle are only beginning to be explored. The cellular mechanisms and molecular pathways used to build and shape excretory tubes appear similar to those used in both unicellular and multicellular tubes in more complex organs, such as the vertebrate vascular system and kidney, making this simple organ system a useful model for understanding disease processes. PMID:27183565

Radium-226 body burden in U miners by measurement of Rn in exhaled breath.

PubMed

Srivastava, G K; Raghavayya, M; Kotrappa, P; Somasundaram, S

1986-02-01

Uranium miners were made to inhale Rn-free medical O2 and exhale through a 5.2-1 A1 chamber before reporting to work. The chamber was sealed and isolated from the sampling circuit. An electrostatic plate collected the freshly formed Rn-decay products. The subsequent programmed alpha counting of the plate yielded a Rn concentration in the exhaled breath. Assuming that the exhaled breath represents a certain fraction of the Rn produced inside the body, the body burden of 226Ra was calculated. Standardisation of this procedure and the data collected on 310 miners are discussed. The procedure is simple and applicable for routine measurements. The miner needs to be in the laboratory for only 10 min. The system is also portable for field application. For routine use, the minimum detectable concentration is 3.87 Bq X m-3 which corresponds to a body burden of 0.26 kBq in a typical miner, if one assumes the Rn release fraction from the body as 84%. The system offers a more convenient and sensitive alternative to whole-body counting of workers for 226Ra.

Molecular simulation of gas adsorption and diffusion in a breathing MOF using a rigid force field.

PubMed

García-Pérez, E; Serra-Crespo, P; Hamad, S; Kapteijn, F; Gascon, J

2014-08-14

Simulation of gas adsorption in flexible porous materials is still limited by the slow progress in the development of flexible force fields. Moreover, the high computational cost of such flexible force fields may be a drawback even when they are fully developed. In this work, molecular simulations of gas adsorption and diffusion of carbon dioxide and methane in NH2-MIL-53(Al) are carried out using a linear combination of two crystallographic structures with rigid force fields. Once the interactions of carbon dioxide molecules and the bridging hydroxyls groups of the framework are optimized, an excellent match is found for simulations and experimental data for the adsorption of methane and carbon dioxide, including the stepwise uptake due to the breathing effect. In addition, diffusivities of pure components are calculated. The pore expansion by the breathing effect influences the self-diffusion mechanism and much higher diffusivities are observed at relatively high adsorbate loadings. This work demonstrates that using a rigid force field combined with a minimum number of experiments, reproduces adsorption and simulates diffusion of carbon dioxide and methane in the flexible metal-organic framework NH2-MIL-53(Al).

Systems Modeling of a Hypothetical SSME Channel-Wall Nozzle

NASA Technical Reports Server (NTRS)

Greene, William D.; Thames, Mignon P.; Polsgrove, Robert H.

2003-01-01

A future upgrade to the Space Shuttle Main Engine (SSME) may be the replacement of the current regenerative cooled tube-wall nozzle with a nozzle using a regeneratively-cooled channel-wall design. The current tube-wall design represents the only major piece of SSME hardware that has not been dramatically updated throughout thc long history of the engine. There are a number of advantages to a channel-wall design including the promise of faster and lower cost fabrication and greater reliability in the field. The technical obstacles in the path of making this happen are many, particularly in the realms of metallurgy and manufacturing techniques. However, one technical area that can and should be addressed in the near term as part of the development of detailed component requirements is a systems type model of the fluid flow and heat transfer processes to which the new design will be exposed. This paper presents the results of an effort to develop a mathematical model of the internal flow for a generic channel-wall nozzle functioning as a direct replacement for the current tube-wall nozzle with a minimum of systems-level changes. Comparisons will be made to mathematical modeling results for the current tube-wall design and the results of various geometrical trade studies will be presented. It is the intent of this work to examine the feasibility of the concept of a direct replacement component with minimum systems-!eve impacts and to highlight potential areas of concern requiring further work in the future.

A novel coupled VM-PT cryocooler operating at liquid helium temperature

NASA Astrophysics Data System (ADS)

Pan, Changzhao; Zhang, Tong; Zhou, Yuan; Wang, Junjie

2016-07-01

This paper presents experimental results on a novel two-stage gas-coupled VM-PT cryocooler, which is a one-stage VM cooler coupled a pulse tube cooler. In order to reach temperatures below the critical point of helium-4, a one-stage coaxial pulse tube cryocooler was gas-coupled on the cold end of the former VM cryocooler. The low temperature inertance tube and room temperature gas reservoir were used as phase shifters. The influence of room temperature double-inlet was first investigated, and the results showed that it added excessive heat loss. Then the inertance tube, regenerator and the length of the pulse tube were researched experimentally. Especially, the DC flow, whose function is similar to the double-orifice, was experimentally studied, and shown to contribute about 0.2 K for the no-load temperature. The minimum no-load temperature of 4.4 K was obtained with a pressure ratio near 1.5, working frequency of 2.2 Hz, and average pressure of 1.73 MPa.

Motion induced interplay effects for VMAT radiotherapy.

PubMed

Edvardsson, Anneli; Nordström, Fredrik; Ceberg, Crister; Ceberg, Sofie

2018-04-19

The purpose of this study was to develop a method to simulate breathing motion induced interplay effects for volumetric modulated arc therapy (VMAT), to verify the proposed method with measurements, and to use the method to investigate how interplay effects vary with different patient- and machine specific parameters. VMAT treatment plans were created on a virtual phantom in a treatment planning system (TPS). Interplay effects were simulated by dividing each plan into smaller sub-arcs using an in-house developed software and shifting the isocenter for each sub-arc to simulate a sin 6 breathing motion in the superior-inferior direction. The simulations were performed for both flattening-filter (FF) and flattening-filter free (FFF) plans and for different breathing amplitudes, period times, initial breathing phases, dose levels, plan complexities, CTV sizes, and collimator angles. The resulting sub-arcs were calculated in the TPS, generating a dose distribution including the effects of motion. The interplay effects were separated from dose blurring and the relative dose differences to 2% and 98% of the CTV volume (ΔD 98% and ΔD 2% ) were calculated. To verify the simulation method, measurements were carried out, both static and during motion, using a quasi-3D phantom and a motion platform. The results of the verification measurements during motion were comparable to the results of the static measurements. Considerable interplay effects were observed for individual fractions, with the minimum ΔD 98% and maximum ΔD 2% being  -16.7% and 16.2%, respectively. The extent of interplay effects was larger for FFF compared to FF and generally increased for higher breathing amplitudes, larger period times, lower dose levels, and more complex treatment plans. Also, the interplay effects varied considerably with the initial breathing phase, and larger variations were observed for smaller CTV sizes. In conclusion, a method to simulate motion induced interplay effects was developed and verified with measurements, which allowed for a large number of treatment scenarios to be investigated. The simulations showed large interplay effects for individual fractions and that the extent of interplay effects varied with the breathing pattern, FFF/FF, dose level, CTV size, collimator angle, and the complexity of the treatment plan.

Motion induced interplay effects for VMAT radiotherapy

NASA Astrophysics Data System (ADS)

Edvardsson, Anneli; Nordström, Fredrik; Ceberg, Crister; Ceberg, Sofie

2018-04-01

The purpose of this study was to develop a method to simulate breathing motion induced interplay effects for volumetric modulated arc therapy (VMAT), to verify the proposed method with measurements, and to use the method to investigate how interplay effects vary with different patient- and machine specific parameters. VMAT treatment plans were created on a virtual phantom in a treatment planning system (TPS). Interplay effects were simulated by dividing each plan into smaller sub-arcs using an in-house developed software and shifting the isocenter for each sub-arc to simulate a sin6 breathing motion in the superior–inferior direction. The simulations were performed for both flattening-filter (FF) and flattening-filter free (FFF) plans and for different breathing amplitudes, period times, initial breathing phases, dose levels, plan complexities, CTV sizes, and collimator angles. The resulting sub-arcs were calculated in the TPS, generating a dose distribution including the effects of motion. The interplay effects were separated from dose blurring and the relative dose differences to 2% and 98% of the CTV volume (ΔD98% and ΔD2%) were calculated. To verify the simulation method, measurements were carried out, both static and during motion, using a quasi-3D phantom and a motion platform. The results of the verification measurements during motion were comparable to the results of the static measurements. Considerable interplay effects were observed for individual fractions, with the minimum ΔD98% and maximum ΔD2% being  ‑16.7% and 16.2%, respectively. The extent of interplay effects was larger for FFF compared to FF and generally increased for higher breathing amplitudes, larger period times, lower dose levels, and more complex treatment plans. Also, the interplay effects varied considerably with the initial breathing phase, and larger variations were observed for smaller CTV sizes. In conclusion, a method to simulate motion induced interplay effects was developed and verified with measurements, which allowed for a large number of treatment scenarios to be investigated. The simulations showed large interplay effects for individual fractions and that the extent of interplay effects varied with the breathing pattern, FFF/FF, dose level, CTV size, collimator angle, and the complexity of the treatment plan.

Fiber-Optic Bio-sniffer (Biochemical Gas Sensor) Using Reverse Reaction of Alcohol Dehydrogenase for Exhaled Acetaldehyde.

PubMed

Iitani, Kenta; Chien, Po-Jen; Suzuki, Takuma; Toma, Koji; Arakawa, Takahiro; Iwasaki, Yasuhiko; Mitsubayashi, Kohji

2018-02-23

Volatile organic compounds (VOCs) exhaled in breath have huge potential as indicators of diseases and metabolisms. Application of breath analysis for disease screening and metabolism assessment is expected since breath samples can be noninvasively collected and measured. In this research, a highly sensitive and selective biochemical gas sensor (bio-sniffer) for gaseous acetaldehyde (AcH) was developed. In the AcH bio-sniffer, a reverse reaction of alcohol dehydrogenase (ADH) was employed for reducing AcH to ethanol and simultaneously consuming a coenzyme, reduced form of nicotinamide adenine dinucleotide (NADH). The concentration of AcH can be quantified by fluorescence detection of NADH that was consumed by reverse reaction of ADH. The AcH bio-sniffer was composed of an ultraviolet light-emitting diode (UV-LED) as an excitation light source, a photomultiplier tube (PMT) as a fluorescence detector, and an optical fiber probe, and these three components were connected with a bifurcated optical fiber. A gas-sensing region of the fiber probe was developed with a flow-cell and an ADH-immobilized membrane. In the experiment, after optimization of the enzyme reaction conditions, the selectivity and dynamic range of the AcH bio-sniffer were investigated. The AcH bio-sniffer showed a short measurement time (within 2 min) and a broad dynamic range for determination of gaseous AcH, 0.02-10 ppm, which encompassed a typical AcH concentration in exhaled breath (1.2-6.0 ppm). Also, the AcH bio-sniffer exhibited a high selectivity to gaseous AcH based on the specificity of ADH. The sensor outputs were observed only from AcH-contained standard gaseous samples. Finally, the AcH bio-sniffer was applied to measure the concentration of AcH in exhaled breath from healthy subjects after ingestion of alcohol. As a result, a significant difference of AcH concentration between subjects with different aldehyde dehydrogenase type 2 (ALDH2) phenotypes was observed. The AcH bio-sniffer can be used for breath measurement, and further, an application of breath analysis-based disease screening or metabolism assessment can be expected due to the versatility of its detection principle, which allows it to measure other VOCs by using NADH-dependent dehydrogenases.

Antibacterial potential assessment of jasmine essential oil against e. Coli.

PubMed

Rath, C C; Devi, S; Dash, S K; Mishra, R K

2008-01-01

The antibacterial activity of Jasmine (Jasminum sambac L.) flower hydro steam distilled essential oil, synthetic blends and six major individual components was assessed against Escherichia coli (MTCC-443) strain. The activity was bactericidal. Minimum inhibitory concentration was determined by tube dilution technique, and the Minimum inhibitory concentration ranged between 1.9-31.25 mul/ml. Phenolcoefficient of the oil, synthetic blends and components varied between 0.6-1.7. The activity of the chemicals was possibly due to the inhibition of cell membrane synthesis.

The microspace launcher: first step to the fully air-breathing space launcher

NASA Astrophysics Data System (ADS)

Falempin, F.; Bouchez, M.; Calabro, M.

2009-09-01

A possible application for the high-speed air-breathing propulsion is the fully or partially reusable space launcher. Indeed, by combining the high-speed air-breathing propulsion with a conventional rocket engine (combined cycle or combined propulsion system), it should be possible to improve the average installed specific impulse along the ascent trajectory and then make possible more performing launchers and, hopefully, a fully reusable one. During the last 15 years, a lot of system studies have been performed in France on that subject within the framework of different and consecutive programs. Nevertheless, these studies never clearly demonstrated that a space launcher could take advantage of using a combined propulsion system. During last years, the interest to air-breathing propulsion for space application has been revisited. During this review and taking into account technologies development activities already in progress in Europe, clear priorities have been identified regarding a minimum complementary research and technology program addressing specific needs of space launcher application. It was also clearly identified that there is the need to restart system studies taking advantage of recent progress made regarding knowledge, tools, and technology and focusing on more innovative airframe/propulsion system concepts enabling better trade-off between structural efficiency and propulsion system performance. In that field, a fully axisymmetric configuration has been considered for a microspace launcher (10 kg payload). The vehicle is based on a main stage powered by air-breathing propulsion, combined or not with liquid rocket mode. A "kick stage," powered by a solid rocket engine provides the final acceleration. A preliminary design has been performed for different variants: one using a separated booster and a purely air-breathing main stage, a second one using a booster and a main stage combining air-breathing and rocket mode, a third one without separated booster, the main stage ensuring the initial acceleration in liquid rocket mode and a complementary acceleration phase in rocket mode beyond the air-breathing propulsion system operation. Finally, the liquid rocket engine of this third variant can be replaced by a continuous detonation wave rocket engine. The paper describes the main guidelines for the design of these variants and provides their main characteristics. On this basis, the achievable performance, estimated by trajectory simulation, are detailed.

Finite Element Modeling of Dieless Tube Drawing of Strain Rate Sensitive Material with Coupled Thermo-Mechanical Analysis

NASA Astrophysics Data System (ADS)

Furushima, Tsuyoshi; Sakai, Takashi; Manabe, Ken-ichi

2004-06-01

Dieless drawing is a unique deformation process without conventional dies, which can achieve a great reduction of wire and tube metals in single pass by means of local heating and cooling approach. In this study, for microtube forming, the dieless drawing process applying superplastic behavior was analyzed by finite element method (FEM) in order to clarify the effect of dieless tube drawing conditions such as tensile speed, moving speed of heating and cooling system, and material properties on deformation behavior of the tube. In the calculation, the material properties were dealt in a special subroutine, whose constitutive equation was defined as σ = Kɛnɛ˙m, and was linked to the solver. A coupled thermo-mechanical analysis was performed for the dieless tube drawing using the FEM. In the thermal analysis of dieless tube drawing, heat transfer was introduced to calculate the heat flux between heating coil and tube surface, and heat conduction in a tube. The influence of dieless tube drawing conditions on deformation behavior was clarified. As a result, for the strain rate sensitive material, the maximum reduction of area and the minimum outer diameter in single pass attain to 90.9% and 2.56mm, respectively. From the result, it is concluded that the dieless tube drawing is essential to produce an extrafine microtube by reason of keeping cylindrical tube diameter ratio constant with extremely high reduction.

Personal exposure to JP-8 jet fuel vapors and exhaust at air force bases.

PubMed

Pleil, J D; Smith, L B; Zelnick, S D

2000-03-01

JP-8 jet fuel (similar to commercial/international jet A-1 fuel) is the standard military fuel for all types of vehicles, including the U.S. Air Force aircraft inventory. As such, JP-8 presents the most common chemical exposure in the Air Force, particularly for flight and ground crew personnel during preflight operations and for maintenance personnel performing routine tasks. Personal exposure at an Air Force base occurs through occupational exposure for personnel involved with fuel and aircraft handling and/or through incidental exposure, primarily through inhalation of ambient fuel vapors. Because JP-8 is less volatile than its predecessor fuel (JP-4), contact with liquid fuel on skin and clothing may result in prolonged exposure. The slowly evaporating JP-8 fuel tends to linger on exposed personnel during their interaction with their previously unexposed colleagues. To begin to assess the relative exposures, we made ambient air measurements and used recently developed methods for collecting exhaled breath in special containers. We then analyzed for certain volatile marker compounds for JP-8, as well as for some aromatic hydrocarbons (especially benzene) that are related to long-term health risks. Ambient samples were collected by using compact, battery-operated, personal whole-air samplers that have recently been developed as commercial products; breath samples were collected using our single-breath canister method that uses 1-L canisters fitted with valves and small disposable breathing tubes. We collected breath samples from various groups of Air Force personnel and found a demonstrable JP-8 exposure for all subjects, ranging from slight elevations as compared to a control cohort to > 100 [mutilpe] the control values. This work suggests that further studies should be performed on specific issues to obtain pertinent exposure data. The data can be applied to assessments of health outcomes and to recommendations for changes in the use of personal protective equipment that optimize risk reduction without undue impact on a mission.

In Vitro Comparison of Aerosol Delivery Using Different Face Masks and Flow Rates With a High-Flow Humidity System.

PubMed

Lin, Hui-Ling; Harwood, Robert J; Fink, James B; Goodfellow, Lynda T; Ari, Arzu

2015-09-01

Aerosol drug delivery to infants and small children is influenced by many factors, such as types of interface, gas flows, and the designs of face masks. The purpose of this in vitro study was to evaluate aerosol delivery during administration of gas flows across the range used clinically with high-flow humidity systems using 2 aerosol masks. A spontaneous lung model was used to simulate an infant/young toddler up to 2 y of age and pediatric breathing patterns. Nebulized salbutamol by a vibrating mesh nebulizer positioned at the inlet of a high-flow humidification system at gas flows of 3, 6, and 12 L/min was delivered via pediatric face masks to a pediatric face mannequin attached to a filter. Aerosol particle size distribution exiting the vibrating mesh nebulizer and at the mask position distal to the heated humidifier with 3 flows was measured with a cascade impactor. Eluted drug from the filters and the impactor was analyzed with a spectrophotometer (n = 3). Statistical analysis was performed by analysis of variance with a significant level of P < .05. The inhaled mass was between 2.8% and 8.1% among all settings and was significantly lower at 12 L/min (P = .004) in the pediatric model. Drug delivery with pediatric breathing was greater than with infant breathing (P = .004). The particle size distribution of aerosol emitted from the nebulizer was larger than the heated humidified aerosol exiting the tubing (P = .002), with no difference between the 3 flows (P = .10). The flows of gas entering the mask and breathing patterns influence aerosol delivery, independent of the face mask used. Aerosol delivery through a high-flow humidification system via mask could be effective with both infant and pediatric breathing patterns. Copyright © 2015 by Daedalus Enterprises.

Popular on YouTube: a critical appraisal of the educational quality of information regarding asthma.

PubMed

Gonzalez-Estrada, Alexei; Cuervo-Pardo, Lyda; Ghosh, Bitan; Smith, Martin; Pazheri, Foussena; Zell, Katrina; Wang, Xiao-Feng; Lang, David M

2015-01-01

Asthma affects >300 million people globally, including 25 million in the United States. Patients with asthma frequently use the Internet as a source of information. YouTube is one of the three most popular Web sites. To determine the educational quality of YouTube videos for asthma. We performed a YouTube search by using the keyword "asthma." The 200 most frequently viewed relevant videos were included in the study. Asthma videos were analyzed for characteristics, source, and content. Source was further classified as asthma health care provider, other health care provider, patient, pharmaceutical company, and professional society and/or media. A scoring system was created to evaluate quality (-10 to 30 points). Negative points were assigned for misleading information. Two hundred videos were analyzed, with a median of 18,073.5 views, 31.5 likes, and 2 dislikes, which spanned a median of 172 seconds. More video presenters were male (60.5%). The most common type of video source was other health care providers (34.5%). The most common video content was alternative treatments (38.0%), including live-fish ingestion; reflexology; acupressure and/or acupuncture; Ayurveda; yoga; raw food, vegan, gluten-free diets; marijuana; Buteyko breathing; and salt therapy. Scores for videos supplied by asthma health care providers were statistically significantly different from other sources (p < 0.001) and had the highest average score (9.91). YouTube videos of asthma were frequently viewed but were a poor source of accurate health care information. Videos by asthma health care providers were rated highest in quality. The allergy/immunology community has a clear opportunity to enhance the value of educational material on YouTube.

Ultrasensitive, real-time analysis of biomarkers in breath using tunable external cavity laser and off-axis cavity-enhanced absorption spectroscopy

NASA Astrophysics Data System (ADS)

Bayrakli, Ismail; Akman, Hatice

2015-03-01

A robust biomedical sensor for ultrasensitive detection of biomarkers in breath based on a tunable external cavity laser (ECL) and an off-axis cavity-enhanced absorption spectroscopy (OA-CEAS) using an amplitude stabilizer is developed. A single-mode, narrow-linewidth, tunable ECL is demonstrated. A broadly coarse wavelength tuning range of 720 cm-1 for the spectral range between 6890 and 6170 cm-1 is achieved by rotating the diffraction grating forming a Littrow-type external-cavity configuration. A mode-hop-free tuning range of 1.85 cm-1 is obtained. The linewidths below 140 kHz are recorded. The ECL is combined with an OA-CEAS to perform laser chemical sensing. Our system is able to detect any molecule in breath at concentrations to the ppbv range that have absorption lines in the spectral range between 1450 and 1620 nm. Ammonia is selected as target molecule to evaluate the performance of the sensor. Using the absorption line of ammonia at 6528.76 cm-1, a minimum detectable absorption coefficient of approximately 1×10-8 cm-1 is demonstrated for 256 averages. This is achieved for a 1.4-km absorption path length and a 2-s data-acquisition time. These results yield a detection sensitivity of approximately 8.6×10-10 cm-1 Hz-1/2. Ammonia in exhaled breath is analyzed and found in a concentration of 870 ppb for our example.

Ultrasensitive, real-time analysis of biomarkers in breath using tunable external cavity laser and off-axis cavity-enhanced absorption spectroscopy.

PubMed

Bayrakli, Ismail; Akman, Hatice

2015-03-01

A robust biomedical sensor for ultrasensitive detection of biomarkers in breath based on a tunable external cavity laser (ECL) and an off-axis cavity-enhanced absorption spectroscopy (OA-CEAS) using an amplitude stabilizer is developed. A single-mode, narrow-linewidth, tunable ECL is demonstrated. A broadly coarse wavelength tuning range of 720 cm⁻¹ for the spectral range between 6890 and 6170 cm⁻¹ is achieved by rotating the diffraction grating forming a Littrow-type external-cavity configuration. A mode-hop-free tuning range of 1.85 cm⁻¹ is obtained. The linewidths below 140 kHz are recorded. The ECL is combined with an OA-CEAS to perform laser chemical sensing. Our system is able to detect any molecule in breath at concentrations to the ppbv range that have absorption lines in the spectral range between 1450 and 1620 nm. Ammonia is selected as target molecule to evaluate the performance of the sensor. Using the absorption line of ammonia at 6528.76 cm⁻¹, a minimum detectable absorption coefficient of approximately 1×10⁻⁸ cm⁻¹ is demonstrated for 256 averages. This is achieved for a 1.4-km absorption path length and a 2-s data-acquisition time. These results yield a detection sensitivity of approximately 8.6×10⁻¹⁰ cm⁻¹ Hz(-1/2). Ammonia in exhaled breath is analyzed and found in a concentration of 870 ppb for our example.

GATING CIRCUITS

DOEpatents

Merrill, L.C.

1958-10-14

Control circuits for vacuum tubes are described, and a binary counter having an improved trigger circuit is reported. The salient feature of the binary counter is the application of the input signal to the cathode of each of two vacuum tubes through separate capacitors and the connection of each cathode to ground through separate diodes. The control of the binary counter is achieved in this manner without special pulse shaping of the input signal. A further advantage of the circuit is the simplicity and minimum nuruber of components required, making its use particularly desirable in computer machines.

Miniature Rocket Motor for Aircraft Stall/Spin Recovery

NASA Technical Reports Server (NTRS)

Lucy, M. H.

1985-01-01

Design accommodates different thrust levels and burn times with minimum weight. Different thrust levels achieved by substituting other propellants of different diameter and burn-rate characteristics. Different burn times achieved by simply changing length of grain/tube assembly. Grain bond material also acts as insulator for fiberglass tube. Rocket motor attached to aircraft model and ignited from radio-controlled 4.8-volt power source. Device provides more than twice energy available in previous designs at only 60 percent of weight. Rocket motor used to identify energy requirements for aircraft stall/spin recovery positive propulsion system.

Estimation of tracheal pressure and imposed expiratory work of breathing by the endotracheal tube, heat and moisture exchanger, and ventilator during mechanical ventilation.

PubMed

Uchiyama, Akinori; Yoshida, Takeshi; Yamanaka, Hidenori; Fujino, Yuji

2013-07-01

The resistance of the endotracheal tube (ETT), the heat and moisture exchanger (HME), and the ventilator may affect the patient's respiratory status. Although previous studies examined the inspiratory work of breathing (WOB), investigation of WOB in the expiratory phase is rare. We estimated tracheal pressure at the tip of the ETT (Ptrach) and calculated expiratory WOB imposed by the ETT, the HME, and the expiratory valve. We examined imposed expiratory WOB in patients under a continuous mandatory ventilation (CMV) mode and during spontaneous breathing trials (SBTs). We hypothesized that imposed expiratory WOB would increase with heightened ventilatory demand. We measured airway pressure (Paw) and respiratory flow (V). We estimated Ptrach using the equation Ptrach = Paw - K1 × V(K2) - 2.70 × V(L/s)(1.42). K1 and K2 were determined by the inner diameter (ID) of the ETT. Imposed expiratory WOB was calculated from the area of Ptrach above PEEP versus lung volume. We examined imposed expiratory WOB and imposed expiratory resistance in relation to mean expiratory flow. We examined 28 patients under CMV mode, and 29 during SBT. During both CMV and SBT, as mean expiratory flow increased, imposed expiratory WOB increased. The regression curves between mean expiratory flow (x) (L/s) and imposed expiratory WOB (y) (J/L) were y = 1.35x(0.83) (R(2) = 0.79) for 7 mm ID ETT under CMV, y = 1.12x(0.82) (R(2) = 0.73) for 8 mm ID ETT under CMV, y = 1.07x(1.04) (R(2) = 0.85) for 7 mm ID ETT during SBT, and y = 0.84x(0.93) (R(2) = 0.75) for 8 mm ID ETT during SBT. Levels of imposed expiratory WOB were affected by ETT diameter and ventilator mode. The reason for increasing imposed expiratory WOB was an increase in expiratory resistance imposed by the ETT and HME. Under mechanical ventilation, imposed expiratory WOB should be considered in patients with higher minute ventilation.

Pitot-tube flowmeter for quantification of airflow during sleep.

PubMed

Kirkness, J P; Verma, M; McGinley, B M; Erlacher, M; Schwartz, A R; Smith, P L; Wheatley, J R; Patil, S P; Amis, T C; Schneider, H

2011-02-01

The gold-standard pneumotachograph is not routinely used to quantify airflow during overnight polysomnography due to the size, weight, bulkiness and discomfort of the equipment that must be worn. To overcome these deficiencies that have precluded the use of a pneumotachograph in routine sleep studies, our group developed a lightweight, low dead space 'pitot flowmeter' (based on pitot-tube principle) for use during sleep. We aimed to examine the characteristics and validate the flowmeter for quantifying airflow and detecting hypopneas during polysomnography by performing a head-to-head comparison with a pneumotachograph. Four experimental paradigms were utilized to determine the technical performance characteristics and the clinical usefulness of the pitot flowmeter in a head-to-head comparison with a pneumotachograph. In each study (1-4), the pitot flowmeter was connected in series with a pneumotachograph under either static flow (flow generator inline or on a face model) or dynamic flow (subject breathing via a polyester face model or on a nasal mask) conditions. The technical characteristics of the pitot flowmeter showed that, (1) the airflow resistance ranged from 0.065 ± 0.002 to 0.279 ± 0.004 cm H(2)O L(-1) s(-1) over the airflow rates of 10 to 50 L min(-1). (2) On the polyester face model there was a linear relationship between airflow as measured by the pitot flowmeter output voltage and the calibrated pneumotachograph signal a (β(1) = 1.08 V L(-1) s(-1); β(0) = 2.45 V). The clinically relevant performance characteristics (hypopnea detection) showed that (3) when the pitot flowmeter was connected via a mask to the human face model, both the sensitivity and specificity for detecting a 50% decrease in peak-to-peak airflow amplitude was 99.2%. When tested in sleeping human subjects, (4) the pitot flowmeter signal displayed 94.5% sensitivity and 91.5% specificity for the detection of 50% peak-to-peak reductions in pneumotachograph-measured airflow. Our data validate the pitot flowmeter for quantification of airflow and detecting breathing reduction during polysomnographic sleep studies. We speculate that quantifying airflow during sleep can differentiate phenotypic traits related to sleep disordered breathing.

Increased risk of Eustachian tube disorders in patients with sleep-disordered breathing

PubMed Central

Chou, Meng-Shih; Chang, Wen-Dien; Lin, Che-Chen; Li, Yu-Fen; Tsou, Yung-An

2017-01-01

Abstract Sleep-disordered breathing (SDB) and Eustachian tube disorders (ETDs) share the same risk factors. The specific aim of this study was to determine the correlation between these 2 conditions and to determine whether treatments for SDB reduce the risk of ETD. This is a retrospective and large population-based cohort study. According to Taiwan's National Health Insurance Research Database, out of 1,000,000 insured patients, 24,251 patients were newly diagnosed with SDB from year 2000 through 2009. The control group for this study comprised 96,827 patients without SDB who were randomly selected from the same database at a ratio of 1:4, frequency matched for sex, age, and index year of SDB. The incidence of developing ETD was compared between these 2 groups; the main covariates were demographic data, interventions, and medical comorbidities. There was an increased risk of developing ETD among the SDB cohort compared with the control group (hazard ratio = 1.51, 95% confidence interval = 1.41–1.63). Compared with SDB patients who did not receive treatment, those who received the treatment, that is, pharyngeal or nasal surgery, CPAP, or multiple modalities (both surgery and CPAP), had a significantly reduced risk of developing ETD. This study showed that patients with SDB are at an increased risk of developing ETD and other comorbidities. The risk of developing ETD can be reduced by implementing prompt treatment for SDB. Multidisciplinary evaluation including ETD should be conducted in the management of patients presenting with SDB. PMID:28767574

Effect of upper airway CO2 pattern on ventilatory frequency in tegu lizards.

PubMed

Ballam, G O; Coates, E L

1989-07-01

Nasal CO2-sensitive receptors are reported to depress ventilatory frequency in several reptilian species in response to constant low levels of inspired CO2. The purpose of this study was to determine the influence of phasic patterns of CO2 in the upper airways on ventilation. Awake lizards (Tupinambis nigropunctatus) breathed through an endotracheal tube from an isolated gas source. A second gas mixture was forced at constant flow into the external nares. A concentration of 4% CO2 was intermittently pulsed through the nares in a square-wave pattern with a frequency of 60, 12, 6, 4.2, 1.8, and 0.6 cycles/min. Concentrations of 2, 3, 4, and 6% CO2 were also pulsed through the nares at 12 cycles/min and compared with sustained levels of 1, 1.5, 2, and 3%. Additionally, 0 or 3% CO2 was forced through the upper airways with a servo system designed to mimic normal ventilatory flow and gas concentrations. No changes in breathing pattern were noted during any of the pulsing protocols, although a significant breathing frequency depression was present with sustained levels of CO2 of comparable mean concentrations. We conclude that ventilatory control is selectively responsive to sustained levels of environmental CO2 but not to phasic changes in upper airway CO2 concentration.

Hydrogen cyanide as a biomarker for Pseudomonas aeruginosa in the breath of children with cystic fibrosis.

PubMed

Enderby, Beth; Smith, David; Carroll, W; Lenney, W

2009-02-01

Hydrogen cyanide (HCN) is emitted by Pseudomonas aeruginosa (PA) in vitro. We hypothesized that exhaled HCN could be measured using Selected Ion Flow Tube Mass Spectrometry (SIFT-MS) and that concentrations would be higher in children with cystic fibrosis (CF) and PA infection than in children with asthma. Children aged 7-17 years with CF (n = 16) or asthma (n = 21) attending outpatient clinics provided breath samples between July and December 2007. HCN was measured using the SIFT-MS Profile 3 instrument. FeNO was measured with a Sievers NOA 280i analyzer. Baseline inter-group differences between HCN and FeNO concentrations were compared using the Mann-Whitney U test. Children were invited to re-attend fortnightly. Breath samples, spirometry, growth and clinical status were measured at each visit. There were significant baseline differences in exhaled HCN and FeNO concentrations between the two groups. Children with CF had higher median HCN concentrations than those with asthma: 13.5 parts per billion (ppb) (IQR 8.1-16.5) versus 2.0 ppb (IQR 0.0-4.8) (P < 0.001). Children with CF had lower median FeNO levels compared to children with asthma: 13.4 ppb (IQR 8.9-17.6) versus 57.9 ppb (IQR 34.0-85.7) (P < 0.001). Intra-subject variability was high and significant changes in HCN concentrations were not observed related to changes in lung function or clinical status. This study provides proof of principle that HCN is detectable in the breath of children with CF and is elevated compared to children with asthma. Further studies are required to capture data from acutely unwell children and more accurately delineate responses to treatment. (c) 2009 Wiley-Liss, Inc.

Postoperative environmental anesthetic vapour concentrations following removal of the airway device in the operating room versus the postanesthesia care unit.

PubMed

Cheung, Sara K; Özelsel, Timur; Rashiq, Saifee; Tsui, Ban C

2016-09-01

This study was designed to compare waste anesthetic gas (WAG) concentrations within patients' breathing zones after removal of the patient's airway device in the postanesthesia care unit (PACU) vs in the operating room (OR). Following Research Ethics Board approval and patient consent, we recruited patients undergoing surgery who received volatile anesthesia via an endotracheal tube or supraglottic airway. Patients had their airway device removed in the OR or in the PACU depending on the attending anesthesiologist's preference. Upon the patient's arrival in the PACU, concentrations of exhaled sevoflurane and desflurane were measured at their breathing zone (i.e., 15 cm from the patient's mouth and nose) using a single-beam infrared spectrophotometer. Seventy patients were recruited during the five-month study period. The median [interquartile range] WAG levels in the patients' breathing zones were higher when their airway devices were removed in the PACU vs in the OR. The WAG levels for sevoflurane were 0.7 [0.4-1.1] parts per million (ppm) vs 0.5 [0.4-0.7] ppm, respectively; median difference, 0.3; 95% confidence interval (CI), 0.1 to 0.6; P = 0.04. The WAG levels for desflurane were 2.4 [1.2-3.4] ppm vs 4.1 [2.5-5.2] ppm, respectively; median difference, 1.5; 95% CI, 0.3 to 2.7; P = 0.04. After a volatile-based anesthetic, our results suggest that removal of the airway device in the PACU vs in the OR increases the amount of waste anesthetic gas in a patient's breathing zone and thus potentially in the PACU nurse's working zone.

Metabolomic analysis of breath volatile organic compounds reveals unique breathprints in children with inflammatory bowel disease: a pilot study.

PubMed

Patel, N; Alkhouri, N; Eng, K; Cikach, F; Mahajan, L; Yan, C; Grove, D; Rome, E S; Lopez, R; Dweik, R A

2014-09-01

Breath testing is becoming an important diagnostic method to evaluate many disease states. In the light of rising healthcare costs, is important to develop a simple non-invasive tool to potentially identify paediatric patients who need endoscopy for suspected inflammatory bowel disease (IBD). To analyse exhaled volatile organic compounds (VOCs) and investigate the presence of a unique breath patterns to differentiate paediatric patients with (IBD) from healthy controls. A cross-sectional, single-centre study included paediatric IBD patients and healthy controls (age range, 5-21 years). The diagnosis of IBD was confirmed by endoscopic, histological and radiographic data. Exhaled breath was collected and analysed using a selective ion flow tube mass spectroscopy (SIFT-MS) to identify new markers or patterns of IBD. One hundred and seventeen patients (62 with IBD and 55 healthy controls) were included in the study. Linear discriminant analysis and principle component analysis of mass scanning ion peak data demonstrated 21 pre-selected VOCs correctly classify patients with IBD or as healthy controls; P < 0.0001. Multivariable logistic regression analysis further showed three specific VOCs (1-octene, 1-decene, (E)-2-nonene) had excellent accuracy for predicting the presence of IBD with an area under the curve (AUC) of 0.96 (95% CI: 0.93-0.99). No significant difference in VOCs was found between patients with Crohn's disease or ulcerative colitis, and no significant correlation was seen with disease activity. These pilot data support the hypothesis that a unique breathprint potentially exists for paediatric IBD in the exhaled metabolome. © 2014 John Wiley & Sons Ltd.

A novel personal air sampling device for collecting volatile organic compounds: a comparison to charcoal tubes and diffusive badges.

PubMed

Rossner, Alan; Farant, Jean-Pierre

2004-02-01

Evacuated canisters have been used for many years to collect ambient air samples for gases and vapors. Recently, significant interest has arisen in using evacuated canisters for personal breathing zone sampling as an alternative to sorbent sampling. A novel flow control device was designed and built at McGill University. The flow control device was designed to provide a very low flow rate, <0.5 mL/min, to allow a sample to be collected over an extended period of time. Previous experiments run at McGill have shown agreement between the mathematical and empirical models to predict flow rate. The flow control device combined with an evacuated canister (capillary flow control-canister) was used in a series of experiments to evaluate its performance against charcoal tubes and diffusive badges. Air samples of six volatile organic compounds were simultaneously collected in a chamber using the capillary flow control-canister, charcoal tubes, and diffusive badges. Five different concentrations of the six volatile organic compounds were evaluated. The results from the three sampling devices were compared to each other and to concentration values obtained using an online gas chromatograph (GC). Eighty-four samples of each method were collected for each of the six chemicals. Results indicate that the capillary flow control-canister device compares quite favorably to the online GC and to the charcoal tubes, p > 0.05 for most of the tests. The capillary flow control-canister was found to be more accurate for the compounds evaluated, easier to use, and easier to analyze than charcoal tubes and passive dosimeter badges.

SU-E-J-33: Cardiac Movement in Deep Inspiration Breath-Hold for Left-Breast Cancer Radiotherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, M; Lee, S; Suh, T

Purpose: The present study was designed to investigate the displacement of heart using Deep Inspiration Breath Hold (DIBH) CT data compared to free-breathing (FB) CT data and radiation exposure to heart. Methods: Treatment planning was performed on the computed tomography (CT) datasets of 20 patients who had received lumpectomy treatments. Heart, lung and both breasts were outlined. The prescribed dose was 50 Gy divided into 28 fractions. The dose distributions in all the plans were required to fulfill the International Commission on Radiation Units and Measurement specifications that include 100% coverage of the CTV with ≥ 95% of the prescribedmore » dose and that the volume inside the CTV receiving > 107% of the prescribed dose should be minimized. Displacement of heart was measured by calculating the distance between center of heart and left breast. For the evaluation of radiation dose to heart, minimum, maximum and mean dose to heart were calculated. Results: The maximum and minimum left-right (LR) displacements of heart were 8.9 mm and 3 mm, respectively. The heart moved > 4 mm in the LR direction in 17 of the 20 patients. The distances between the heart and left breast ranged from 8.02–17.68 mm (mean, 12.23 mm) and 7.85–12.98 mm (mean, 8.97 mm) with DIBH CT and FB CT, respectively. The maximum doses to the heart were 3115 cGy and 4652 cGy for the DIBH and FB CT dataset, respectively. Conclusion: The present study has demonstrated that the DIBH technique could help to reduce the risk of radiation dose-induced cardiac toxicity by using movement of cardiac; away from radiation field. The DIBH technique could be used in an actual treatment room for a few minutes and could effectively reduce the cardiac dose when used with a sub-device or image acquisition standard to maintain consistent respiratory motion.« less

Management of Pneumothorax in Emergency Medicine Departments: Multicenter Trial

PubMed Central

Ince, Abdulkadir; Ozucelik, Dogac Niyazi; Avci, Akkan; Nizam, Ozgur; Dogan, Halil; Topal, Mehmet Ali

2013-01-01

Background: Pneumothorax is common and life-threatening clinical condition which may require emergency treatment in Emergency Medicine Departments. Objectives: We aimed to reveal the epidemiological analysis of the patients admitted to the Emergency Department with pneumothorax. Material and Methods: This case-control and multi-center study was conducted in the patients treated with the diagnosis of pneumothorax between 01.01.2010-31.12.2010. Patient data were collected from hospital automation system. According to the etiology of the pneumothorax, study groups were arranged like spontaneous pneumothorax and traumatic pneumothorax. Results: 82.2% (n = 106) of patients were male and 17.8% (n = 23) of patients were female and mean age were 31.3 ± 20,2 (Minimum: 1, Maximum: 87). 68.2% (n = 88) of patients were spontaneous pneumothorax (61.36%, n=79 were primary spontaneous pneumothorax) and 31.8% (n = 41) of patients were traumatic pneumothorax (21.95% were iatrogenic pneumothorax). Main complaint is shortness of breath (52.3%, n=67) and 38% (n=49) of patients were smokers. Posteroanterior (PA) Chest X-Ray has been enough for 64.3% (n = 83) of the patients' diagnosis. Tube thoracostomy is applied to 84.5% (n = 109) of patients and surgery is applied to 9.3% (n = 12) of patients and 6.2% (n = 8) of patients were discharged with conservative treatment. Spontaneous pneumothorax showed statistically significant high recurrence compared with traumatic pneumothorax (P = 0.007). 4.65% of (n = 6) patients died. The average age of those who died (9.3 ± 19.9), statistically were significantly lower the mean age of living patients (32.4 ± 19.7) (t test, P = 0,006). 83.33% of the patients who died were neonatals and in the 0-1 years age group, and five of these patients were secondary spontaneous pneumothorax, and one of these patients were iatrogenic pneumothorax due to mechanical ventilation. Conclusions: Pneumothorax in adults can be treated by tube thoracostomy or surgically. Despite treatment, mortality of secondary and iatrogenic pneumothorax in newborns and 0-1 years age group is high. PMID:24693384

The effect of viscoelasticity on the stability of a pulmonary airway liquid layer

NASA Astrophysics Data System (ADS)

Halpern, David; Fujioka, Hideki; Grotberg, James B.

2010-01-01

The lungs consist of a network of bifurcating airways that are lined with a thin liquid film. This film is a bilayer consisting of a mucus layer on top of a periciliary fluid layer. Mucus is a non-Newtonian fluid possessing viscoelastic characteristics. Surface tension induces flows within the layer, which may cause the lung's airways to close due to liquid plug formation if the liquid film is sufficiently thick. The stability of the liquid layer is also influenced by the viscoelastic nature of the liquid, which is modeled using the Oldroyd-B constitutive equation or as a Jeffreys fluid. To examine the role of mucus alone, a single layer of a viscoelastic fluid is considered. A system of nonlinear evolution equations is derived using lubrication theory for the film thickness and the film flow rate. A uniform film is initially perturbed and a normal mode analysis is carried out that shows that the growth rate g for a viscoelastic layer is larger than for a Newtonian fluid with the same viscosity. Closure occurs if the minimum core radius, Rmin(t), reaches zero within one breath. Solutions of the nonlinear evolution equations reveal that Rmin normally decreases to zero faster with increasing relaxation time parameter, the Weissenberg number We. For small values of the dimensionless film thickness parameter ɛ, the closure time, tc, increases slightly with We, while for moderate values of ɛ, ranging from 14% to 18% of the tube radius, tc decreases rapidly with We provided the solvent viscosity is sufficiently small. Viscoelasticity was found to have little effect for ɛ >0.18, indicating the strong influence of surface tension. The film thickness parameter ɛ and the Weissenberg number We also have a significant effect on the maximum shear stress on tube wall, max(τw), and thus, potentially, an impact on cell damage. Max(τw) increases with ɛ for fixed We, and it decreases with increasing We for small We provided the solvent viscosity parameter is sufficiently small. For large ɛ ≈0.2, there is no significant difference between the Newtonian flow case and the large We cases.

Investigation of energy transport within a pulse tube

NASA Astrophysics Data System (ADS)

Waldauf, A.; Schmauder, T.; Thürk, M.; Seidel, P.

2002-05-01

A compact Four-Valve Pulse Tube Refrigerator (FVPTR) in U-tube configuration without a reservoir has been built. At present, the cooler provides a minimum temperature of 32 K and 100 W of cooling power at 90 K with a nominal input power of 5.6 kW. Experiments were performed to study the special refrigeration mechanisms of the FVPTR. The highly instrumented system that includes gas temperature sensors, hot wire anemometers and pressure sensors is used to assess the p-V work and enthalpy flow at the key locations in the pulse tube. The experiments have enabled us to verify the various analytical models of the FVPTR. Based on the first law of thermodynamics for open systems we have estimated the gross refrigeration power for this special type of pulse tube refrigerator. Furthermore our model takes typical loss processes into consideration to analyze the real FVPTR process. These calculations need some assumptions about the real flow behavior and the time-dependent temperatures within the pulse tube. The accuracy of these assumptions will be checked by our experiments. By using these results a further technical improvement of our FVPTR should be possible.

Concentric Tube Robot Design and Optimization Based on Task and Anatomical Constraints

PubMed Central

Bergeles, Christos; Gosline, Andrew H.; Vasilyev, Nikolay V.; Codd, Patrick J.; del Nido, Pedro J.; Dupont, Pierre E.

2015-01-01

Concentric tube robots are catheter-sized continuum robots that are well suited for minimally invasive surgery inside confined body cavities. These robots are constructed from sets of pre-curved superelastic tubes and are capable of assuming complex 3D curves. The family of 3D curves that the robot can assume depends on the number, curvatures, lengths and stiffnesses of the tubes in its tube set. The robot design problem involves solving for a tube set that will produce the family of curves necessary to perform a surgical procedure. At a minimum, these curves must enable the robot to smoothly extend into the body and to manipulate tools over the desired surgical workspace while respecting anatomical constraints. This paper introduces an optimization framework that utilizes procedureor patient-specific image-based anatomical models along with surgical workspace requirements to generate robot tube set designs. The algorithm searches for designs that minimize robot length and curvature and for which all paths required for the procedure consist of stable robot configurations. Two mechanics-based kinematic models are used. Initial designs are sought using a model assuming torsional rigidity. These designs are then refined using a torsionally-compliant model. The approach is illustrated with clinically relevant examples from neurosurgery and intracardiac surgery. PMID:26380575

Challenges to plant growing in space.

PubMed

Langhans, R W; Dreesen, D R

1988-04-01

Picture yourself a million miles from earth; it's lunch time. What will you eat: meat, fish, bread, fresh vegetables (cooked or uncooked), or food from a tube? What will happen to the waste products from the processed food or even from yourself? What will you breathe? These and hundreds of detailed questions must be answered. At present, we have little knowledge about a totally closed environment life support system (CELSS). We have developed in this paper a list of references that are pertinent to the problem. It is divided into subject areas and listed chronologically, rather than alphabetically.

Personal continuous air monitor

DOEpatents

Morgan, Ronald G.; Salazar, Samuel A.

2000-01-01

A personal continuous air monitor capable of giving immediate warning of the presence of radioactivity has a filter/detector head to be worn in the breathing zone of a user, containing a filter mounted adjacent to radiation detectors, and a preamplifier. The filter/detector head is connected to a belt pack to be worn at the waist or on the back of a user. The belt pack contains a signal processor, batteries, a multichannel analyzer, a logic circuit, and an alarm. An air pump also is provided in the belt pack for pulling air through the filter/detector head by way of an air tube.

Challenges to plant growing in space

NASA Technical Reports Server (NTRS)

Langhans, R. W.; Dreesen, D. R.

1988-01-01

Picture yourself a million miles from earth; it's lunch time. What will you eat: meat, fish, bread, fresh vegetables (cooked or uncooked), or food from a tube? What will happen to the waste products from the processed food or even from yourself? What will you breathe? These and hundreds of detailed questions must be answered. At present, we have little knowledge about a totally closed environment life support system (CELSS). We have developed in this paper a list of references that are pertinent to the problem. It is divided into subject areas and listed chronologically, rather than alphabetically.

Cavity ring down spectrometry for disease diagnostics using exhaled air

NASA Astrophysics Data System (ADS)

Revalde, G.; Grundšteins, K.; Alnis, J.; Skudra, A.

2017-12-01

In this paper we report the current stage of the development of a cavity ring-down spectrometer (CRDS) system using exhaled human breath analysis for the diagnostics of different diseases like diabetes and later lung cancer. The portable CRDS system is made in ultraviolet spectral region using Nd:Yag laser 266 nm pulsed light. Calibration of the CRDS system was performed using generated samples by KinTek automated permeation tube system and self-prepared mixtures with known concentration of benzene and acetone in air. First experiments showed that the limits of detection for benzene and acetone are several tens of ppb.

10 K high frequency pulse tube cryocooler with precooling

NASA Astrophysics Data System (ADS)

Liu, Sixue; Chen, Liubiao; Wu, Xianlin; Zhou, Yuan; Wang, Junjie

2016-07-01

A high frequency pulse tube cryocooler with precooling (HPTCP) has been developed and tested to meet the requirement of weak magnetic signals measurement, and the performance characteristics are presented in this article. The HPTCP is a two-stage pulse tube cryocooler with the precooling-stage replaced by liquid nitrogen. Two regenerators completely filled with stainless steel (SS) meshes are used in the cooler. Together with cold inertance tubes and cold gas reservoir, a cold double-inlet configuration is used to control the phase relationship of the HPTCP. The experimental result shows that the cold double-inlet configuration has improved the performance of the cooler obviously. The effects of operation parameters on the performance of the cooler are also studied. With a precooling temperature of 78.5 K, the maximum refrigeration capacity is 0.26 W at 15 K and 0.92 W at 20 K when the input electric power are 174 W and 248 W respectively, and the minimum no-load temperature obtained is 10.3 K, which is a new record on refrigeration temperature for high frequency pulse tube cryocooler reported with SS completely used as regenerative matrix.

Design, construction and long life endurance testing of cathode assemblies for use in microwave high-power transmitting tubes

NASA Technical Reports Server (NTRS)

Gorshe, R.

1982-01-01

The ability of state of the art cathode types to produce current densities of 2A/sq cm, respectively, over a minimum designed life of 30,000 hours of continuous operation without failures was demonstrated. The performance of the state of the art cathode types was evaluated by endurance testing while operating under identical electrical geometrical, and vacuum conditions that realistically duplicate the operating conditions present in a transmitter tube. Although there has been considerable life testing done on high current density types of cathodes, these have beem primarily limited to diodes. A diode and high power microwave tube are grossly different devices. A comparison of these two devices is provided. A diode and high power microwave tube are quite different; one could therefore assume different internal environments, especially in the cathode region. Therefore, in order to establish life capabilities of the cathodes just mentioned, they should be tested in a vehicle which has an internal environment similar to that of a high power microwave tube.

Antibacterial Potential Assessment of Jasmine Essential Oil Against E. Coli

PubMed Central

Rath, C. C.; Devi, S.; Dash, S. K.; Mishra, R. K.

2008-01-01

The antibacterial activity of Jasmine (Jasminum sambac L.) flower hydro steam distilled essential oil, synthetic blends and six major individual components was assessed against Escherichia coli (MTCC-443) strain. The activity was bactericidal. Minimum inhibitory concentration was determined by tube dilution technique, and the Minimum inhibitory concentration ranged between 1.9-31.25 μl/ml. Phenolcoefficient of the oil, synthetic blends and components varied between 0.6-1.7. The activity of the chemicals was possibly due to the inhibition of cell membrane synthesis. PMID:20046722

Pressure support versus T-tube for weaning from mechanical ventilation in adults.

PubMed

Ladeira, Magdaline T; Vital, Flávia M R; Andriolo, Régis B; Andriolo, Brenda N G; Atallah, Alvaro N; Peccin, Maria S

2014-05-27

Mechanical ventilation is important in caring for patients with critical illness. Clinical complications, increased mortality, and high costs of health care are associated with prolonged ventilatory support or premature discontinuation of mechanical ventilation. Weaning refers to the process of gradually or abruptly withdrawing mechanical ventilation. The weaning process begins after partial or complete resolution of the underlying pathophysiology precipitating respiratory failure and ends with weaning success (successful extubation in intubated patients or permanent withdrawal of ventilatory support in tracheostomized patients). To evaluate the effectiveness and safety of two strategies, a T-tube and pressure support ventilation, for weaning adult patients with respiratory failure that required invasive mechanical ventilation for at least 24 hours, measuring weaning success and other clinically important outcomes. We searched the following electronic databases: Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2012, Issue 6); MEDLINE (via PubMed) (1966 to June 2012); EMBASE (January 1980 to June 2012); LILACS (1986 to June 2012); CINAHL (1982 to June 2012); SciELO (from 1997 to August 2012); thesis repository of CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior) (http://capesdw.capes.gov.br/capesdw/) (August 2012); and Current Controlled Trials (August 2012).We reran the search in December 2013. We will deal with any studies of interest when we update the review. We included randomized controlled trials (RCTs) that compared a T-tube with pressure support (PS) for the conduct of spontaneous breathing trials and as methods of gradual weaning of adult patients with respiratory failure of various aetiologies who received invasive mechanical ventilation for at least 24 hours. Two authors extracted data and assessed the methodological quality of the included studies. Meta-analyses using the random-effects model were conducted for nine outcomes. Relative risk (RR) and mean difference (MD) or standardized mean difference (SMD) were used to estimate the treatment effect, with 95% confidence intervals (CI). We included nine RCTs with 1208 patients; 622 patients were randomized to a PS spontaneous breathing trial (SBT) and 586 to a T-tube SBT. The studies were classified into three categories of weaning: simple, difficult, and prolonged. Four studies placed patients in two categories of weaning. Pressure support ventilation (PSV) and a T-tube were used directly as SBTs in four studies (844 patients, 69.9% of the sample). In 186 patients (15.4%) both interventions were used along with gradual weaning from mechanical ventilation; the PS was gradually decreased, twice a day, until it was minimal and periods with a T-tube were gradually increased to two and eight hours for patients with difficult and prolonged weaning. In two studies (14.7% of patients) the PS was lowered to 2 to 4 cm H2O and 3 to 5 cm H2O based on ventilatory parameters until the minimal PS levels were reached. PS was then compared to the trial with the T-tube (TT).We identified 33 different reported outcomes in the included studies; we took 14 of them into consideration and performed meta-analyses on nine. With regard to the sequence of allocation generation, allocation concealment, selective reporting and attrition bias, no study presented a high risk of bias. We found no clear evidence of a difference between PS and TT for weaning success (RR 1.07, 95% CI 0.97 to 1.17, 9 studies, low quality of evidence), intensive care unit (ICU) mortality (RR 0.81, 95% CI 0.53 to 1.23, 5 studies, low quality of evidence), reintubation (RR 0.92, 95% CI 0.66 to 1.26, 7 studies, low quality evidence), ICU and long-term weaning unit (LWU) length of stay (MD -7.08 days, 95% CI -16.26 to 2.1, 2 studies, low quality of evidence) and pneumonia (RR 0.67, 95% CI 0.08 to 5.85, 2 studies, low quality of evidence). PS was significantly superior to the TT for successful SBTs (RR 1.09, 95% CI 1.02 to 1.17, 4 studies, moderate quality of evidence). Four studies reported on weaning duration, however we were unable to combined the study data because of differences in how the studies presented their data. One study was at high risk of other bias and four studies were at high risk for detection bias. Three studies reported that the weaning duration was shorter with PS, and in one study the duration was shorter in patients with a TT. To date, we have found evidence of generally low quality from studies comparing pressure support ventilation (PSV) and with a T-tube. The effects on weaning success, ICU mortality, reintubation, ICU and LWU length of stay, and pneumonia were imprecise. However, PSV was more effective than a T-tube for successful spontaneous breathing trials (SBTs) among patients with simple weaning. Based on the findings of single trials, three studies presented a shorter weaning duration in the group undergoing PS SBT, however a fourth study found a shorter weaning duration with a T-tube.

What to Do if a Compact Fluorescent Light (CFL) Bulb or Fluorescent Tube Light Bulb Breaks: Printable Instructions

EPA Pesticide Factsheets

The broken bulb can continue to release mercury vapor until it is cleaned up and removed. This cleanup guidance represents minimum recommended actions to reduce mercury exposure, and will be updated as more efficient practices are identified.

A Large Tracking Detector In Vacuum Consisting Of Self-Supporting Straw Tubes

NASA Astrophysics Data System (ADS)

Wintz, P.

2004-02-01

A novel technique to stretch the anode wire simply by the gas over-pressure inside straw drift tubes reduces the necessary straw weight to an absolute minimum. Our detector will consist of more than 3000 straws filling up a cylindrical tracking volume of 1m diameter and 30cm length. The projected spatial resolution is 200μm. The detector with a total mass of less than 15kg will be operated in vacuum, but will have an added wall thickness of 3mm mylar, only. The detector design, production experience and first results will be discussed.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chow, Kam Kong; Zeng, Haishan, E-mail: hzeng@bccrc.ca; Short, Michael

Purpose: Breath analysis has a potential prospect to benefit the medical field based on its perceived advantages to become a point-of-care, easy to use, and cost-effective technology. Early studies done by mass spectrometry show that volatile organic compounds from human breath can represent certain disease states of our bodies, such as lung cancer, and revealed the potential of breath analysis. But mass spectrometry is costly and has slow-turnaround time. The authors’ goal is to develop a more portable and cost effective device based on Raman spectroscopy and hollow core-photonic crystal fiber (HC-PCF) for breath analysis. Methods: Raman scattering is amore » photon-molecular interaction based on the kinetic modes of an analyte which offers unique fingerprint type signals that allow molecular identification. HC-PCF is a novel light guide which allows light to be confined in a hollow core and it can be filled with a gaseous sample. Raman signals generated by the gaseous sample (i.e., human breath) can be guided and collected effectively for spectral analysis. Results: A Raman-cell based on HC-PCF in the near infrared wavelength range was developed and tested in a single pass forward-scattering mode for different gaseous samples. Raman spectra were obtained successfully from reference gases (hydrogen, oxygen, carbon dioxide gases), ambient air, and a human breath sample. The calculated minimum detectable concentration of this system was ∼15 parts per million by volume, determined by measuring the carbon dioxide concentration in ambient air via the characteristic Raman peaks at 1286 and 1388 cm{sup −1}. Conclusions: The results of this study were compared to a previous study using HC-PCF to trap industrial gases and backward-scatter 514.5 nm light from them. The authors found that the method presented in this paper has an advantage to enhance the signal-to-noise ratio (SNR). This SNR advantage, coupled with the better transmission of HC-PCF in the near-IR than in the visible wavelengths led to an estimated seven times improvement in the detection sensitivity. The authors’ prototype device also demonstrated a 100-fold improvement over a recently reported detection limit of a reflective capillary fiber-based Raman cell for breath analysis. Continued development is underway to increase the detection sensitivity further to reach practical clinical applications.« less

Delay time correction of the gas analyzer in the calculation of anatomical dead space of the lung.

PubMed

Okubo, T; Shibata, H; Takishima, T

1983-07-01

By means of a mathematical model, we have studied a way to correct the delay time of the gas analyzer in order to calculate the anatomical dead space using Fowler's graphical method. The mathematical model was constructed of ten tubes of equal diameter but unequal length, so that the amount of dead space varied from tube to tube; the tubes were emptied sequentially. The gas analyzer responds with a time lag from the input of the gas signal to the beginning of the response, followed by an exponential response output. The single breath expired volume-concentration relationship was examined with three types of expired flow patterns of which were constant, exponential and sinusoidal. The results indicate that the time correction by the lag time plus time constant of the exponential response of the gas analyzer gives an accurate estimation of anatomical dead space. Time correction less inclusive than this, e.g. lag time only or lag time plus 50% response time, gives an overestimation, and a correction larger than this results in underestimation. The magnitude of error is dependent on the flow pattern and flow rate. The time correction in this study is only for the calculation of dead space, as the corrected volume-concentration curves does not coincide with the true curve. Such correction of the output of the gas analyzer is extremely important when one needs to compare the dead spaces of different gas species at a rather faster flow rate.

A parametric study of the copper chloride laser

NASA Technical Reports Server (NTRS)

Nerheim, N. M.

1977-01-01

A parametric study of the double-pulsed copper chloride laser is reported. The effects of a wide range of variables on the laser energy density and on three characteristic time intervals (the minimum, maximum, and optimum delay time) between the two electrical-discharge pulses were studied. The geometric variables investigated included a tube diameter of 2.3 to 40 mm and a tube length of 3 to 60 cm. Three buffer gases, helium, neon, and argon, were studied over the pressure range 0.5-50 torr, and the tube temperature was varied from 270 to 500 C. The energy density and voltage of both the dissociation and pumping pulse were varied independently from less than 1 mJ/cu cm at 8.5 kV to over 500 mJ/cu cm at 20 kV. The optimum conditions for maximum laser energy density were found to be with 20 torr neon in a 10-mm by 30-cm tube at 400 C. The maximum energy density obtained was 22 microjoules/cu cm.

Mini-tapping sugar maples for sap-sugar testing

Treesearch

William J. Gabriel

1982-01-01

Describes a technique using cannulas, surgical tubing, and small containers to obtain sap samples for use in determining the sugar content of sap in small sugar maple trees. This technique is used on trees directly exposed to the weather, and sets a minimum tappable tree diameter of 1.5 cm.

46 CFR 28.835 - Fuel systems.

Code of Federal Regulations, 2012 CFR

2012-10-01

... flexible tubing or hose is permitted in the fuel supply line at or near the engine to prevent damage by vibration. If nonmetallic flexible hose is used it must: (1) Not exceed the minimum length needed to allow... with wire braid; (4) Be fitted with suitable, corrosion resistant, compression fittings; and (5) Be...

46 CFR 28.835 - Fuel systems.

Code of Federal Regulations, 2014 CFR

2014-10-01

... flexible tubing or hose is permitted in the fuel supply line at or near the engine to prevent damage by vibration. If nonmetallic flexible hose is used it must: (1) Not exceed the minimum length needed to allow... with wire braid; (4) Be fitted with suitable, corrosion resistant, compression fittings; and (5) Be...

46 CFR 28.835 - Fuel systems.

Code of Federal Regulations, 2013 CFR

2013-10-01

... flexible tubing or hose is permitted in the fuel supply line at or near the engine to prevent damage by vibration. If nonmetallic flexible hose is used it must: (1) Not exceed the minimum length needed to allow... with wire braid; (4) Be fitted with suitable, corrosion resistant, compression fittings; and (5) Be...

46 CFR 28.835 - Fuel systems.

Code of Federal Regulations, 2010 CFR

2010-10-01

... flexible tubing or hose is permitted in the fuel supply line at or near the engine to prevent damage by vibration. If nonmetallic flexible hose is used it must: (1) Not exceed the minimum length needed to allow... with wire braid; (4) Be fitted with suitable, corrosion resistant, compression fittings; and (5) Be...

Feeding tubes and health costs postinsertion in nursing home residents with advanced dementia.

PubMed

Hwang, Deborah; Teno, Joan M; Gozalo, Pedro; Mitchell, Susan

2014-06-01

The best evidence suggests that feeding tubes are ineffective in persons with advanced dementia. Little is known about their health care costs. To estimate Medicare costs attributable to inpatient care among nursing home (NH) residents with advanced dementia during the year following the placement of a percutaneous endoscopic gastrostomy (PEG) tube during an index hospitalization. Medicare claims (1999-2009) and Minimum Data Set data (1999-2009) were used to estimate Medicare costs attributable to inpatient care among NH residents with advanced dementia during the year following the placement of a PEG tube and compared with those who did not get a PEG tube. The study used a 3:1 propensity-matched cohort design. Matched residents with (n=1924, 68.9% female, 28.8% African American, average age 83.1 years) and without (weighted n=1924, unique n=4337) PEG insertion showed comparable sociodemographic characteristics, similar rates of feeding tube risk factors, and similar mortality (51.9% 180 day mortality among those with a feeding tube vs. 49.8% among those without a feeding tube, P=0.11). One year hospital costs were $2224 higher in NH residents with a feeding tube ($10,191 vs. $7967, 95% CI of difference=$1514, $2933), with those with a feeding tube likely to spend more time in an intensive care unit (1.92 vs. 1.29 days, 95% CI of difference=0.34, 0.92 days). In an analysis controlling for selection bias, PEG tube insertion is associated with a small but significant increase in annual inpatient health care costs, as well as in hospital and intensive care unit days, postinsertion. Copyright © 2014 U.S. Cancer Pain Relief Committee. Published by Elsevier Inc. All rights reserved.

Design and Control of a Mechatronic Tracheostomy Tube for Automated Tracheal Suctioning.

PubMed

Do, Thanh Nho; Seah, Tian En Timothy; Phee, Soo Jay

2016-06-01

Mechanical ventilation is required to aid patients with breathing difficulty to breathe more comfortably. A tracheostomy tube inserted through an opening in the patient neck into the trachea is connected to a ventilator for suctioning. Currently, nurses spend millions of person-hours yearly to perform this task. To save significant person-hours, an automated mechatronic tracheostomy system is needed. This system allows for relieving nurses and other carers from the millions of person-hours spent yearly on tracheal suctioning. In addition, it will result in huge healthcare cost savings. We introduce a novel mechatronic tracheostomy system including the development of a long suction catheter, automatic suctioning mechanisms, and relevant control approaches to perform tracheal suctioning automatically. To stop the catheter at a desired position, two approaches are introduced: 1) Based on the known travel length of the catheter tip; 2) Based on a new sensing device integrated at the catheter tip. It is known that backlash nonlinearity between the suction catheter and its conduit as well as in the gear system of the actuator are unavoidable. They cause difficulties to control the exact position of the catheter tip. For the former case, we develop an approximate model of backlash and a direct inverse scheme to enhance the system performances. The scheme does not require any complex inversions of the backlash model and allows easy implementations. For the latter case, a new sensing device integrated into the suction catheter tip is developed and backlash compensation controls are avoided. Automated suctioning validations are successfully carried out on the proposed experimental system. Comparisons and discussions are also introduced. The results demonstrate a significant contribution and potential benefits to the mechanical ventilation areas.

SIFT-MS and FA-MS methods for ambient gas phase analysis: developments and applications in the UK.

PubMed

Smith, David; Španěl, Patrik

2015-04-21

Selected ion flow tube mass spectrometry, SIFT-MS, a relatively new gas/vapour phase analytical method, is derived from the much earlier selected ion flow tube, SIFT, used for the study of gas phase ion-molecule reactions. Both the SIFT and SIFT-MS techniques were conceived and developed in the UK, the former at Birmingham University, the latter at Keele University along with the complementary flowing afterglow mass spectrometry, FA-MS, technique. The focus of this short review is largely to describe the origins, developments and, most importantly, the unique features of SIFT-MS as an analytical tool for ambient analysis and to indicate its growing use to analyse humid air, especially exhaled breath, its unique place as a on-line, real time analytical method and its growing use and applications as a non-invasive diagnostic in clinical diagnosis and therapeutic monitoring, principally within several UK universities and hospitals, and briefly in the wider world. A few case studies are outlined that show the potential of SIFT-MS and FA-MS in the detection and quantification of metabolites in exhaled breath as a step towards recognising pathophysiology indicative of disease and the presence of bacterial and fungal infection of the airways and lungs. Particular cases include the detection of Pseudomonas aeruginosa infection of the airways of patients with cystic fibrosis (SIFT-MS) and the measurement of total body water in patients with chronic kidney disease (FA-MS). The growing exploitation of SIFT-MS in other areas of research and commerce are briefly listed to show the wide utility of this unique UK-developed analytical method, and future prospects and developments are alluded to.

Effect of APAP and heated humidification with a heated breathing tube on adherence, quality of life, and nasopharyngeal complaints.

PubMed

Nilius, Georg; Franke, Karl J; Domanski, Ulrike; Schroeder, Maik; Ruhle, Karl H

2016-03-01

Positive airway pressure (PAP) therapy adherence can be affected by rhinitis sicca and xerostomia complaints. Additional heated humidification (HH) is the appropriate method when such complaints arise. The aim of this study was to determine if HH with a supplementary heated breathing tube can increase adherence, reduce subjective nasopharyngeal complaints (NPC), and improve sleepiness (ESS: Epworth Sleepiness Scale) and quality of life (FOSQ: Functional Outcome of Sleep Questionnaire). We subdivided 72 obstructive sleep apnea (OSA) patients into two groups before therapy initiation. The NPC risk group consists of subjects with NPC and the low-risk group without. The risk group was identified by a score of >9 in a 5-item 25-point NPC questionnaire and pathological ESS. All patients were eligible for automatic CPAP devices (APAP), which were randomly configured with or without HH during 6 weeks. The adherence differences with and without HH were not significant in the NPC risk group (330 ± 103 vs. 281 ± 118 min/night) and in the low-risk group (330 ± 116 vs. 321 ± 89). NPC and ESS scores in the risk group were both significantly reduced with HH. Daily function (FOSQ) in the risk group was significantly improved with HH (90.0 ± 11.9 vs. 82.0 ± 12.0 (p < 0.05)). HH showed a tendency to improve APAP adherence. The adherence in both groups was quite high, and for that reason, it is difficult to show a statistically significant effect. A differentiation into NPC risk groups before starting PAP treatment is useful. HH reduces side effects and sleepiness and improves quality of life in an NPC risk group.

Vocal warm-up and breathing training for teachers: randomized clinical trial

PubMed Central

Pereira, Lílian Paternostro de Pina; Masson, Maria Lúcia Vaz; Carvalho, Fernando Martins

2015-01-01

OBJECTIVE To compare the effectiveness of two speech therapy interventions, vocal warm-up and breathing training, focusing on teachers’ voice quality. METHODS A single-blind, randomized, parallel clinical trial was conducted. The research included 31 20 to 60-year old teachers from a public school in Salvador, BA, Northeasatern Brazil, with minimum workloads of 20 hours a week, who have or have not reported having vocal alterations. The exclusion criteria were the following: being a smoker, excessive alcohol consumption, receiving additional speech therapy assistance while taking part in the study, being affected by upper respiratory tract infections, professional use of the voice in another activity, neurological disorders, and history of cardiopulmonary pathologies. The subjects were distributed through simple randomization in groups vocal warm-up (n = 14) and breathing training (n = 17). The teachers’ voice quality was subjectively evaluated through the Voice Handicap Index (Índice de Desvantagem Vocal, in the Brazilian version) and computerized voice analysis (average fundamental frequency, jitter, shimmer, noise, and glottal-to-noise excitation ratio) by speech therapists. RESULTS Before the interventions, the groups were similar regarding sociodemographic characteristics, teaching activities, and vocal quality. The variations before and after the intervention in self-assessment and acoustic voice indicators have not significantly differed between the groups. In the comparison between groups before and after the six-week interventions, significant reductions in the Voice Handicap Index of subjects in both groups were observed, as wells as reduced average fundamental frequencies in the vocal warm-up group and increased shimmer in the breathing training group. Subjects from the vocal warm-up group reported speaking more easily and having their voices more improved in a general way as compared to the breathing training group. CONCLUSIONS Both interventions were similar regarding their effects on the teachers’ voice quality. However, each contribution has individually contributed to improve the teachers’ voice quality, especially the vocal warm-up. PMID:26465664

Breath-holding times in various phases of respiration and effect of respiratory training in lung cancer patients.

PubMed

Tibdewal, Anil; Munshi, Anusheel; Pathak, Rima; Misra, Shagun; Daptardar, Anuradha; Singh, Vincent; Agarwal, Jai Prakash

2015-08-01

Breath-holding (BH) technique is used for reducing the intrafraction-tumour motion in mobile lung tumours treated with radiotherapy (RT). There is paucity of literature evaluating differences in BH times in various phases of respiration in patients with lung cancer. One hundred consecutive patients with lung cancer planned for radical RT/chemoradiation were accrued in the study. Eighty-seven patients were eligible for analysis at RT conclusion. Baseline pulmonary function test (PFT) were performed in all patients, and respiratory training was given from the day of RT planning. Deep inspiration breath hold (DIBH), deep expiration breath hold (DEBH) and mid-ventilation breath hold (MVBH) were recorded manually with a stopwatch for each patient at four time points (RT planning/baseline, RT starting, during RT and RT conclusion). Median DIBH times at RT planning, RT starting, during RT and RT conclusion were 21.2, 20.6, 20.1 and 21.1 s, respectively. The corresponding median DEBH and MVBH times were 16.3, 18.2, 18.3, 18.5 s and 19.9, 20.5, 21.3, 22.1 s, respectively. Respiratory training increased MVBH time at RT conclusion compared to baseline, which was statistically significant (19.9-22.1 s, P = 0.002). DIBH or DEBH times were stable at various time points with neither a significant improvement nor decline. Among various patient and tumour factors Forced Vital Capacity pre-bronchodilation (FVCpre ) was the only factor that consistently predicted DIBH, DEBH and MVBH at all four time points with P value <0.05. BH was well tolerated by most lung cancer patients with minimum median BH time of at least 16 s in any of the three phases of respiration. Respiratory training improved MVBH time while consistently maintaining DIBH and DEBH times throughout the course of radiotherapy. © 2015 The Royal Australian and New Zealand College of Radiologists.

Failing left ventricle to ascending aorta conduit-Hybrid implantation of a melody valve and NuMed covered stent.

PubMed

Gössl, Mario; Johnson, Jonathan N; Hagler, Donald J

2014-04-01

We present the case of a 36-year-old woman with increasing shortness of breath, a new 3/4 diastolic murmur, and a complex history of LV outflow tract obstruction. She has undergone multiple surgeries including the replacement of her old LV apex to ascending aorta conduit with a 20-mm Gore-Tex tube graft, addition of a 24-mm homograft sutured between the conduit and the LV apex, and insertion of a 21-mm Freestyle porcine valve conduit between the Gore-Tex tube graft and allograft at age 23. The current assessment showed a failing Freestyle conduit prosthesis leading to left heart decompensation. Due to substantial surgical risk, the patient underwent successful implantation of a Melody valve into the Gore-Tex tube and exclusion of the failing Freestyle bioprosthesis with a NuMed CP stent in a hybrid procedure. The case nicely illustrates the collaborative potential of cardiovascular surgeons and interventional cardiologists in the new arena of a hybrid operating room. Complex hybrid procedures like the current one, especially those including percutaneous placements of valves, offer therapeutic options for patients that are otherwise too high risk for conventional open heart surgery. Copyright © 2013 Wiley Periodicals, Inc.

Formaldehyde exposure in gross anatomy laboratory of Suranaree University of Technology: a comparison of area and personal sampling.

PubMed

Saowakon, Naruwan; Ngernsoungnern, Piyada; Watcharavitoon, Pornpun; Ngernsoungnern, Apichart; Kosanlavit, Rachain

2015-12-01

Cadavers are usually preserved by embalming solution which is composed of formaldehyde (FA), phenol, and glycerol. Therefore, medical students and instructors have a higher risk of exposure to FA inhalation from cadavers during dissection. Therefore, the objective of this study was to evaluate the FA exposure in indoor air and breathing zone of medical students and instructors during dissection classes in order to investigate the relationship between them. The indoor air and personal air samples in breathing zone were collected three times during anatomy dissection classes (in January, August, and October of 2014) with sorbent tubes, which were analyzed by high-performance liquid chromatography (HPLC). The air cleaner machines were determined by weight measurement. Pulmonary function tests and irritation effects were also investigated. The mean of FA concentrations ranged from 0.117 to 0.415 ppm in the indoor air and from 0.126 to 1.176 ppm in the breathing zone of students and instructors. All the personal exposure data obtained exceeded the threshold limit of NIOSH and WHO agencies. The air cleaner machines were not significant difference. The pulmonary function of instructors showed a decrease during attention of classes and statistically significant decreasing in the instructors more than those of the students. Clinical symptoms that were observed in nose and eyes were irritations with general fatigue. We suggested that the modified exhaust ventilation and a locally ventilated dissection work table were considered for reducing FA levels in the gross anatomy dissection room.

Breathprints of childhood obesity: changes in volatile organic compounds in obese children compared with lean controls.

PubMed

Alkhouri, N; Eng, K; Cikach, F; Patel, N; Yan, C; Brindle, A; Rome, E; Hanouneh, I; Grove, D; Lopez, R; Hazen, S L; Dweik, Raed A

2015-02-01

The objective of this study was to investigate changes in volatile organic compounds (VOCs) in exhaled breath in overweight/obese children compared with their lean counterparts. Single exhaled breath was collected and analyzed per protocol using selective ion flow tube mass spectrometry (SIFT-MS). Sixty overweight/obese children and 55 lean controls were included. Compared with the lean group, the obese group was significantly older (14.1 ± 2.8 vs. 12.1 ± 3.0 years), taller (164.8 ± 10.9 vs. 153.3 ± 17.1 cm) and more likely to be Caucasian (60% vs. 35.2%); P < 0.05 for all. A comparison of the SIFT-MS results of the obese group with the lean group revealed differences in concentration of more than 50 compounds. A panel of four VOCs can identify the presence of overweight/obesity with excellent accuracy. Further analysis revealed that breath isoprene, 1-decene, 1-octene, ammonia and hydrogen sulfide were significantly higher in the obese group compared with the lean group (P value < 0.01 for all). Obese children have a unique pattern of exhaled VOCs. Changes in VOCs observed in this study may help to gain insight into pathophysiological processes and pathways leading to the development of childhood obesity. © 2014 The Authors. Pediatric Obesity © 2014 International Association for the Study of Obesity.

[Basic concepts of radiology physics].

PubMed

Gambini, D-J

2010-11-01

An x-ray tube mainly emits low-energy X-rays, with few maximum energy E₀ (equal in keV to the voltage U in kV) x-rays. Aluminium filtration (mandatory minimum thickness of 1.5 to 2.5 mm based on tube voltage) reduces soft X-rays and provides a mean energy equal to 2/3 E₀. The half value layer of a reference material characterizes the spectrum. X-ray attenuation in tissues is due to secondary electron interactions: photoelectric effect at low-energy, especially in dense materials with high Z number; compton effect at intermediate-energy, proportional to density. The optimization of acquisition parameters of a medically necessary examination is based on appropriate selection of the highest voltage (U in kV) providing the best contrast and lowest tube current (Q in mAs) providing a diagnostic image.

An allowable cladding peak temperature for spent nuclear fuels in interim dry storage

NASA Astrophysics Data System (ADS)

Cha, Hyun-Jin; Jang, Ki-Nam; Kim, Kyu-Tae

2018-01-01

Allowable cladding peak temperatures for spent fuel cladding integrity in interim dry storage were investigated, considering hydride reorientation and mechanical property degradation behaviors of unirradiated and neutron irradiated Zr-Nb cladding tubes. Cladding tube specimens were heated up to various temperatures and then cooled down under tensile hoop stresses. Cool-down specimens indicate that higher heat-up temperature and larger tensile hoop stress generated larger radial hydride precipitation and smaller tensile strength and plastic hoop strain. Unirradiated specimens generated relatively larger radial hydride precipitation and plastic strain than did neutron irradiated specimens. Assuming a minimum plastic strain requirement of 5% for cladding integrity maintenance in interim dry storage, it is proposed that a cladding peak temperature during the interim dry storage is to keep below 250 °C if cladding tubes are cooled down to room temperature.

Measurements and computations of mass flow and momentum flux through short tubes in rarefied gases

NASA Astrophysics Data System (ADS)

Lilly, T. C.; Gimelshein, S. F.; Ketsdever, A. D.; Markelov, G. N.

2006-09-01

Gas flows through orifices and short tubes have been extensively studied from the 1960s through the 1980s for both fundamental and practical reasons. These flows are a basic and often important element of various modern gas driven instruments. Recent advances in micro- and nanoscale technologies have paved the way for a generation of miniaturized devices in various application areas, from clinical analyses to biochemical detection to aerospace propulsion. The latter is the main area of interest of this study, where rarefied gas flow into a vacuum through short tubes with thickness-to-diameter ratios varying from 0.015 to 1.2 is investigated both experimentally and numerically with kinetic and continuum approaches. Helium and nitrogen gases are used in the range of Reynolds numbers from 0.02 to 770 (based on the tube diameter), corresponding to Knudsen numbers from 40 down to about 0.001. Propulsion properties of relatively thin and thick tubes are examined. Good agreement between experimental and numerical results is observed for mass flow rate and momentum flux, the latter being corrected for the experimental facility background pressure. For thick-to-thin tube ratios of mass flow and momentum flux versus pressure, a minimum is observed at a Knudsen number of about 0.5. A short tube propulsion efficiency is shown to be much higher than that of a thin orifice. The effect of surface specularity on a thicker tube specific impulse was found to be relatively small.

Personal exposure to JP-8 jet fuel vapors and exhaust at air force bases.

PubMed Central

Pleil, J D; Smith, L B; Zelnick, S D

2000-01-01

JP-8 jet fuel (similar to commercial/international jet A-1 fuel) is the standard military fuel for all types of vehicles, including the U.S. Air Force aircraft inventory. As such, JP-8 presents the most common chemical exposure in the Air Force, particularly for flight and ground crew personnel during preflight operations and for maintenance personnel performing routine tasks. Personal exposure at an Air Force base occurs through occupational exposure for personnel involved with fuel and aircraft handling and/or through incidental exposure, primarily through inhalation of ambient fuel vapors. Because JP-8 is less volatile than its predecessor fuel (JP-4), contact with liquid fuel on skin and clothing may result in prolonged exposure. The slowly evaporating JP-8 fuel tends to linger on exposed personnel during their interaction with their previously unexposed colleagues. To begin to assess the relative exposures, we made ambient air measurements and used recently developed methods for collecting exhaled breath in special containers. We then analyzed for certain volatile marker compounds for JP-8, as well as for some aromatic hydrocarbons (especially benzene) that are related to long-term health risks. Ambient samples were collected by using compact, battery-operated, personal whole-air samplers that have recently been developed as commercial products; breath samples were collected using our single-breath canister method that uses 1-L canisters fitted with valves and small disposable breathing tubes. We collected breath samples from various groups of Air Force personnel and found a demonstrable JP-8 exposure for all subjects, ranging from slight elevations as compared to a control cohort to > 100 [mutilpe] the control values. This work suggests that further studies should be performed on specific issues to obtain pertinent exposure data. The data can be applied to assessments of health outcomes and to recommendations for changes in the use of personal protective equipment that optimize risk reduction without undue impact on a mission. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 PMID:10706522

The development and evaluation of a non-pressurised, chemical oxygen reaction generation vessel and breathing system providing emergency oxygen for an extended duration.

PubMed

Dingley, J; Williams, D; Douglas, P; Douglas, M; Douglas, J O

2016-12-01

The objective was to develop a sodium percarbonate/water/catalyst chemical oxygen generator that did not require compressed gas. Existing devices utilising this reaction have a very short duration of action. Preliminary experiments with a glass reaction vessel, water bath and electronic flowmeter indicated that many factors affected oxygen production rate including reagent formulation, temperature, water volume and agitation frequency. Having undertaken full-scale experiments using a stainless steel vessel, an optimum combination of reagents was found to be 1 litre water, 0.75 g manganese dioxide catalyst, 60 g sodium percarbonate granules and 800 g of custom pressed 7.21 (0.28) g sodium percarbonate tablets. This combination of granules and slower dissolution tablets produced a rapid initial oxygen flow to 'purge' an attached low-flow breathing system allowing immediate use, followed by a constant flow meeting metabolic requirements for a minimum of 1 h duration. © 2016 The Association of Anaesthetists of Great Britain and Ireland.

Development of a highly sensitive one-tube nested real-time PCR for detecting Mycobacterium tuberculosis.

PubMed

Choi, Yeonim; Jeon, Bo-Young; Shim, Tae Sun; Jin, Hyunwoo; Cho, Sang-Nae; Lee, Hyeyoung

2014-12-01

Rapid, accurate detection of Mycobacterium tuberculosis is crucial in the diagnosis of tuberculosis (TB), but conventional diagnostic methods have limited sensitivity and specificity or are time consuming. A new highly sensitive nucleic acid amplification test, combined nested and real-time polymerase chain reaction (PCR) in a single tube (one-tube nested real-time PCR), was developed for detecting M. tuberculosis, which takes advantage of two PCR techniques, i.e., nested PCR and real-time PCR. One-tube nested real-time PCR was designed to have two sequential reactions with two sets of primers and dual probes for the insertion sequence (IS) 6110 sequence of M. tuberculosis in a single closed tube. The minimum limits of detection of IS6110 real-time PCR and IS6110 one-tube nested real-time PCR were 100 fg/μL and 1 fg/μL of M. tuberculosis DNA, respectively. AdvanSure TB/non-tuberculous mycobacteria (NTM) real-time PCR, IS6110 real-time PCR, and two-tube nested real-time PCR showed 100% sensitivity and 100% specificity for clinical M. tuberculosis isolates and NTM isolates. In comparison, the sensitivities of AdvanSure TB/NTM real-time PCR, single IS6110 real-time PCR, and one-tube nested real-time PCR were 91% (152/167), 94.6% (158/167), and 100% (167/167) for sputum specimens, respectively. In conclusion, IS6110 one-tube nested real-time PCR is useful for detecting M. tuberculosis due to its high sensitivity and simple manipulation. Copyright © 2014 Elsevier Inc. All rights reserved.

Aerophagia as a cause of ineffective phrenic nerve pacing in high tetraplegia: a case report.

PubMed

Colachis, Sam C; Kadyan, Vivek

2003-05-01

We report an unusual case of aerophagia after traumatic spinal cord injury (SCI), which shows the profound effects of abdominal distension on respiratory ability in such individuals. In this case, abdominal distension resulting from aerophagia reduced the effectiveness of phrenic nerve pacing on diaphragm function necessitating greater use of positive-pressure ventilatory (PPV) support. Reduction of postprandial gastric air and abdominal distension with insertion of a percutaneous endoscopic gastrostomy tube ameliorated the condition and allowed for more effective phrenic nerve pacing and greater PPV-free breathing. We are unaware of a similar case involving an individual with an SCI.

Flutist produces four resonances with a single bottle

NASA Astrophysics Data System (ADS)

Ruiz, Michael J.; Boysen, Erika

2017-03-01

In a dramatic physics demonstration, a professional flutist produces four resonances with a 12 ounce Boylan soda bottle solely through her breath control. The 22 cm bottle acts like a Helmholtz resonator for the lowest pitch. The three higher pitches fall near the 3rd, 5th, and 7th harmonics for a 22 cm closed pipe. A video of this remarkable feat is provided (Ruiz 2016 YouTube: Four Resonances with a 12-ounce Soda Bottle (https://youtu.be/ibtVrp2NF_k)). The video also reveals that a flutist can bend resonance pitches by as much as 10% through control of air speed.

Multi-layer thermoelectric-temperature-mapping microbial incubator designed for geo-biochemistry applications.

PubMed

Wu, Jin-Gen; Liu, Man-Chi; Tsai, Ming-Fei; Yu, Wei-Shun; Chen, Jian-Zhang; Cheng, I-Chun; Lin, Pei-Chun

2012-04-01

We demonstrate a novel, vertical temperature-mapping incubator utilizing eight layers of thermoelectric (TE) modules mounted around a test tube. The temperature at each layer of the TE module is individually controlled to simulate the vertical temperature profile of geo-temperature variations with depth. Owing to the constraint of non-intrusion to the filled geo-samples, the temperature on the tube wall is adopted for measurement feedback. The design considerations for the incubator include spatial arrangement of the energy transfer mechanism, heating capacity of the TE modules, minimum required sample amount for follow-up instrumental or chemical analysis, and the constraint of non-intrusion to the geo-samples during incubation. The performance of the incubator is experimentally evaluated with two tube conditions and under four preset temperature profiles. Test tubes are either empty or filled with quartz sand, which has comparable thermal properties to the materials in the geo-environment. The applied temperature profiles include uniform, constant temperature gradient, monotonic-increasing parabolic, and parabolic. The temperature on the tube wall can be controlled between 20 °C and 90 °C with an averaged root mean squared error of 1 °C. © 2012 American Institute of Physics

46 CFR 56.50-75 - Diesel fuel systems.

Code of Federal Regulations, 2013 CFR

2013-10-01

...-90. The fuel supply piping to engines shall be of seamless steel, annealed seamless copper or brass... except that flareless fittings of the nonbite type may be used when the tubing system is steel, nickel... having a minimum wall thickness of 0.035 inch except that piping of other materials such as seamless...

46 CFR 56.50-75 - Diesel fuel systems.

Code of Federal Regulations, 2010 CFR

2010-10-01

...-90. The fuel supply piping to engines shall be of seamless steel, annealed seamless copper or brass... except that flareless fittings of the nonbite type may be used when the tubing system is steel, nickel... having a minimum wall thickness of 0.035 inch except that piping of other materials such as seamless...

46 CFR 56.50-75 - Diesel fuel systems.

Code of Federal Regulations, 2014 CFR

2014-10-01

...-90. The fuel supply piping to engines shall be of seamless steel, annealed seamless copper or brass... except that flareless fittings of the nonbite type may be used when the tubing system is steel, nickel... having a minimum wall thickness of 0.035 inch except that piping of other materials such as seamless...

46 CFR 56.50-75 - Diesel fuel systems.

Code of Federal Regulations, 2012 CFR

2012-10-01

...-90. The fuel supply piping to engines shall be of seamless steel, annealed seamless copper or brass... except that flareless fittings of the nonbite type may be used when the tubing system is steel, nickel... having a minimum wall thickness of 0.035 inch except that piping of other materials such as seamless...

46 CFR 56.50-75 - Diesel fuel systems.

Code of Federal Regulations, 2011 CFR

2011-10-01

...-90. The fuel supply piping to engines shall be of seamless steel, annealed seamless copper or brass... except that flareless fittings of the nonbite type may be used when the tubing system is steel, nickel... having a minimum wall thickness of 0.035 inch except that piping of other materials such as seamless...

24 CFR 3280.703 - Minimum standards.

Code of Federal Regulations, 2014 CFR

2014-04-01

... Standard Specification for Pipe, Steel, Black and Hot-Dipped, Zinc-Coated, Welded and Seamless—ASTM A53-93. Standard Specification for Electric-Resistance-Welded Coiled Steel Tubing for Gas and Fuel Oil Lines—ASTM A539-1999. Pipe Threads, General Purpose (Inch)—ANSI/ASME B1.20.1-1983. Welding and Seamless Wrought...

46 CFR 162.039-3 - Requirements.

Code of Federal Regulations, 2013 CFR

2013-10-01

... fitted with hose of sufficient length to a nozzle or nozzles to provide for suitable application of the... the hose connection); shall weigh more than 55 pounds when fully charged; shall be self-contained, i.e... which will withstand a minimum bursting pressure of 6,000 p.s.i., and a discharge hose or tube which...

46 CFR 162.039-3 - Requirements.

Code of Federal Regulations, 2011 CFR

2011-10-01

... fitted with hose of sufficient length to a nozzle or nozzles to provide for suitable application of the... the hose connection); shall weigh more than 55 pounds when fully charged; shall be self-contained, i.e... which will withstand a minimum bursting pressure of 6,000 p.s.i., and a discharge hose or tube which...

46 CFR 162.039-3 - Requirements.

Code of Federal Regulations, 2014 CFR

2014-10-01

... fitted with hose of sufficient length to a nozzle or nozzles to provide for suitable application of the... the hose connection); shall weigh more than 55 pounds when fully charged; shall be self-contained, i.e... which will withstand a minimum bursting pressure of 6,000 p.s.i., and a discharge hose or tube which...

46 CFR 162.039-3 - Requirements.

Code of Federal Regulations, 2010 CFR

2010-10-01

... fitted with hose of sufficient length to a nozzle or nozzles to provide for suitable application of the... the hose connection); shall weigh more than 55 pounds when fully charged; shall be self-contained, i.e... which will withstand a minimum bursting pressure of 6,000 p.s.i., and a discharge hose or tube which...

46 CFR 162.039-3 - Requirements.

Code of Federal Regulations, 2012 CFR

2012-10-01

... fitted with hose of sufficient length to a nozzle or nozzles to provide for suitable application of the... the hose connection); shall weigh more than 55 pounds when fully charged; shall be self-contained, i.e... which will withstand a minimum bursting pressure of 6,000 p.s.i., and a discharge hose or tube which...

Effect of water on hydrogen permeability

NASA Technical Reports Server (NTRS)

Hulligan, David; Tomazic, William A.

1987-01-01

Doping of hydrogen with CO and CO2 was developed to reduce hydrogen permeation in Stirling engines by forming a low permeability oxide coating on the inner surface of the heater head tubes. Although doping worked well, under certain circumstances the protective oxide could be chemically reduced by the hydrogen in the engine. Some oxygen is required in the hydrogen to prevent reduction. Eventually, all the oxygen in the hydrogen gas - whatever its source - shows up as water. This is the result of hydrogen reducing the CO, CO2, or the protective inner surface oxides. This water can condense in the engine system under the right conditions. If the concentration of water vapor is reduced to a low enough level, the hydrogen can chemically reduce the oxide coating, resulting in an increase in permeability. This work was done to define the minimum water content required to avoid this reduction in the oxide coating. The results of this testing show that a minimum of approximately 750 ppm water is required to prevent an increase in permeability of CG-27, a high temperature metal alloy selected for Stirling engine heater tubes.

Convective heater

DOEpatents

Thorogood, Robert M.

1986-01-01

A convective heater for heating fluids such as a coal slurry is constructed of a tube circuit arrangement which obtains an optimum temperature distribution to give a relatively constant slurry film temperature. The heater is constructed to divide the heating gas flow into two equal paths and the tube circuit for the slurry is arranged to provide a mixed flow configuration whereby the slurry passes through the two heating gas paths in successive co-current, counter-current and co-current flow relative to the heating gas flow. This arrangement permits the utilization of minimum surface area for a given maximum film temperature of the slurry consistent with the prevention of coke formation.

Convective heater

DOEpatents

Thorogood, Robert M.

1983-01-01

A convective heater for heating fluids such as a coal slurry is constructed of a tube circuit arrangement which obtains an optimum temperature distribution to give a relatively constant slurry film temperature. The heater is constructed to divide the heating gas flow into two equal paths and the tube circuit for the slurry is arranged to provide a mixed flow configuration whereby the slurry passes through the two heating gas paths in successive co-current, counter-current and co-current flow relative to the heating gas flow. This arrangement permits the utilization of minimum surface area for a given maximum film temperature of the slurry consistent with the prevention of coke formation.

Convective heater

DOEpatents

Thorogood, R.M.

1983-12-27

A convective heater for heating fluids such as a coal slurry is constructed of a tube circuit arrangement which obtains an optimum temperature distribution to give a relatively constant slurry film temperature. The heater is constructed to divide the heating gas flow into two equal paths and the tube circuit for the slurry is arranged to provide a mixed flow configuration whereby the slurry passes through the two heating gas paths in successive co-current, counter-current and co-current flow relative to the heating gas flow. This arrangement permits the utilization of minimum surface area for a given maximum film temperature of the slurry consistent with the prevention of coke formation. 14 figs.

Forensic Fluid Dynamics and the Indian Spring (1991) cave collapse problem

NASA Astrophysics Data System (ADS)

Nof, D.

2013-05-01

The collapse of the Indian spring cave (Florida) in 1991 was unique because it occurred while cave divers were in the cave. For the most part, the submerged cave is large enough to accommodate a passing truck so the cave divers were not in touch with its walls and it is hard to imagine why would it naturally collapse just when the divers were in it. Recently, Nof and Paldor (2010) resolved this apparent paradox by suggesting that resonance in the air pockets in the cavern, created by breathing (open circuit) divers, may have contributed to the collapse. In this scenario, divers present in the cavern during the dive may have (unknowingly) caused the collapse through the pressurized air/gas that they release with each breath. When the breathing period of the diver(s) matches the natural oscillations period of the "cave oscillator", the ensuing resonance causes the air pressure in the pockets to increase uncontrollably. Here, we place the above theory on a more solid ground. To do so, we first extended the resonance theory from our original two-pockets, symmetrical U-tube model (with two identical branches that were not specifically identified within the cave system) to a one (identified) pocket in the cavern and a very broad basin (identified, of course) that serves as the other branch of the U-tube. Our methodology is to apply familiar fluid dynamics principles to the situation that occurred in the cave. We did so, step-by-step, on the basis of our interviews with four out of the five surviving cave-divers. Namely, we dissected their testimonies to arrive at a physically plausible scenario determined on basis of a fluid dynamics application to the natural flow in the cave and the flow induced by the compressed air released by the divers as well as the collapsed mud. We found that the oscillation period was larger than what we earlier calculated (still relevant to the case, nevertheless), and that, in contrast to what most cave divers believe, there was a temporary flow blocking during the collapse but no total flow reversal within the cave. Observed swirling in the basin during the collapse is attributed to a dipole flow corresponding to an inflow and outflow from the cave.

Progressive Return to Activity Following Acute Concussion/Mild Traumatic Brain Injury: Guidance for the Rehabilitation Provider in Deployed and Non-deployed Settings

DTIC Science & Technology

2014-01-01

activity requires minimum 2 hours of rest • Video games , driving simulation ― 20 minutes to maximum of 40 minutes, followed by 80 minutes cognitive...as breath-holding, exertion, playing video games and driving. He is encouraged to monitor his HR before and during activity (not to exceed 40 percent...walking at low speed b) Shopping in the exchange for a single item c) Video games d) Television with rest breaks each hour Knowledge Test

The basis for the development of a fuselage evacuation time for a ditched helicopter.

PubMed

Brooks, C J; Muir, H C; Gibbs, P N

2001-06-01

When a helicopter ditches or crashes in water, unless the buoyancy bags are inflated, it commonly sinks inverted. Thus, crew and passengers must make an underwater escape. It is postulated that later passengers in the escape sequence do not have the breath-holding ability to conduct a successful escape, particularly if the water is cold. This contributes to the 20-50% mortality rate in survivable accidents. There were 132 immersed subject evaluations which were conducted in daylight and darkness to measure escape times from a helicopter underwater escape trainer, configured to the Super Puma, seated for 15 and 18 passengers. The subjects were highly experienced instructors or Navy clearance divers. The time from when each subject's head disappeared underwater until each subject surfaced and total fuselage evacuation time were measured and any problems hampering escape were noted. Breath-holding for the last subject out ranged from 28 to 92 s. An emergency breathing system was used by a minimum of four subjects each time and a maximum of 11 subjects in one condition. The buoyancy of the survival suit was the principal component that hampered escape. Breath-holding times were too long for the later subjects to escape without resorting to an EBS, in spite of the fact that they were highly trained. For regular crew and passengers flying over water, this would explain the high mortality, etc. Therefore, a new helicopter standard should be developed requiring fuselage design to accommodate total evacuation within 20 s from underwater. For current helicopters, where this cannot be achieved, passengers should be provided with some form of air supply, or, after ditching, the helicopter should be modified so that it will stay afloat on its side and retain an air space in the cabin.

Ultra-short heart rate variability recording reliability: The effect of controlled paced breathing.

PubMed

Melo, Hiago M; Martins, Thiago C; Nascimento, Lucas M; Hoeller, Alexandre A; Walz, Roger; Takase, Emílio

2018-06-04

Recent studies have reported that Heart Rate Variability (HRV) indices remain reliable even during recordings shorter than 5 min, suggesting the ultra-short recording method as a valuable tool for autonomic assessment. However, the minimum time-epoch to obtain a reliable record for all HRV domains (time, frequency, and Poincare geometric measures), as well as the effect of respiratory rate on the reliability of these indices remains unknown. Twenty volunteers had their HRV recorded in a seated position during spontaneous and controlled respiratory rhythms. HRV intervals with 1, 2, and 3 min were correlated with the gold standard period (6-min duration) and the mean values of all indices were compared in the two respiratory rhythm conditions. rMSSD and SD1 were more reliable for recordings with ultra-short duration at all time intervals (r values from 0.764 to 0.950, p < 0.05) for spontaneous breathing condition, whereas the other indices require longer recording time to obtain reliable values. The controlled breathing rhythm evokes stronger r values for time domain indices (r values from 0.83 to 0.99, p < 0.05 for rMSSD), but impairs the mean values replicability of domains across most time intervals. Although the use of standardized breathing increases the correlations coefficients, all HRV indices showed an increase in mean values (t values from 3.79 to 14.94, p < 0.001) except the RR and HF that presented a decrease (t = 4.14 and 5.96, p < 0.0001). Our results indicate that proper ultra-short-term recording method can provide a quick and reliable source of cardiac autonomic nervous system assessment. © 2018 Wiley Periodicals, Inc.

Minimization of Dead-Periods in MRI Pulse Sequences for Imaging Oblique Planes

PubMed Central

Atalar, Ergin; McVeigh, Elliot R.

2007-01-01

With the advent of breath-hold MR cardiac imaging techniques, the minimization of TR and TE for oblique planes has become a critical issue. The slew rates and maximum currents of gradient amplifiers limit the minimum possible TR and TE by adding dead-periods to the pulse sequences. We propose a method of designing gradient waveforms that will be applied to the amplifiers instead of the slice, readout, and phase encoding waveforms. Because this method ensures that the gradient amplifiers will always switch at their maximum slew rate, it results in the minimum possible dead-period for given imaging parameters and scan plane position. A GRASS pulse sequence has been designed and ultra-short TR and TE values have been obtained with standard gradient amplifiers and coils. For some oblique slices, we have achieved shorter TR and TE values than those for nonoblique slices. PMID:7869900

Evidence of large empty lava tubes on the Moon using GRAIL gravity

NASA Astrophysics Data System (ADS)

Chappaz, Loic; Sood, Rohan; Melosh, Henry J.; Howell, Kathleen C.; Blair, David M.; Milbury, Colleen; Zuber, Maria T.

2017-01-01

NASA's GRAIL mission employed twin spacecraft in polar orbits around the Moon to measure the lunar gravity field at unprecedentedly high accuracy and resolution. The low spacecraft altitude in the extended mission enables the detection of small-scale surface or subsurface features. We analyzed these data for evidence of empty lava tubes beneath the lunar maria. We developed two methods, gradiometry and cross correlation, to isolate the target signal of long, narrow, sinuous mass deficits from a host of other features present in the GRAIL data. Here we report the discovery of several strong candidates that are either extensions of known lunar rilles, collocated with the recently discovered "skylight" caverns, or underlying otherwise unremarkable surfaces. Owing to the spacecraft polar orbits, our techniques are most sensitive to east-west trending near-surface structures and empty lava tubes with minimum widths of several kilometers, heights of hundreds of meters, and lengths of tens of kilometers.

Fluid Mechanics Optimising Organic Synthesis

NASA Astrophysics Data System (ADS)

Leivadarou, Evgenia; Dalziel, Stuart

2015-11-01

The Vortex Fluidic Device (VFD) is a new ``green'' approach in the synthesis of organic chemicals with many industrial applications in biodiesel generation, cosmetics, protein folding and pharmaceutical production. The VFD is a rapidly rotating tube that can operate with a jet feeding drops of liquid reactants to the base of the tube. The aim of this project is to explain the fluid mechanics of the VFD that influence the rate of reactions. The reaction rate is intimately related to the intense shearing that promotes collision between reactant molecules. In the VFD, the highest shears are found at the bottom of the tube in the Rayleigh and the Ekman layer and at the walls in the Stewardson layers. As a step towards optimising the performance of the VFD we present experiments conducted in order to establish the minimum drop volume and maximum rotation rate for maximum axisymmetric spreading without fingering instability. PhD candidate, Department of Applied Mathematics and Theoretical Physics.

Exposure to household air pollution from wood combustion and association with respiratory symptoms and lung function in nonsmoking women: results from the RESPIRE trial, Guatemala.

PubMed

Pope, Daniel; Diaz, Esperanza; Smith-Sivertsen, Tone; Lie, Rolv T; Bakke, Per; Balmes, John R; Smith, Kirk R; Bruce, Nigel G

2015-04-01

With 40% of the world's population relying on solid fuel, household air pollution (HAP) represents a major preventable risk factor for COPD (chronic obstructive pulmonary disease). Meta-analyses have confirmed this relationship; however, constituent studies are observational, with virtually none measuring exposure directly. We estimated associations between HAP exposure and respiratory symptoms and lung function in young, nonsmoking women in rural Guatemala, using measured carbon monoxide (CO) concentrations in exhaled breath and personal air to assess exposure. The Randomized Exposure Study of Pollution Indoors and Respiratory Effects (RESPIRE) Guatemala study was a trial comparing respiratory outcomes among 504 women using improved chimney stoves versus traditional cookstoves. The present analysis included 456 women with data from postintervention surveys including interviews at 6, 12, and 18 months (respiratory symptoms) and spirometry and CO (ppm) in exhaled breath measurements. Personal CO was measured using passive diffusion tubes at variable times during the study. Associations between CO concentrations and respiratory health were estimated using random intercept regression models. Respiratory symptoms (cough, phlegm, wheeze, or chest tightness) during the previous 6 months were positively associated with breath CO measured at the same time of symptom reporting and with average personal CO concentrations during the follow-up period. CO in exhaled breath at the same time as spirometry was associated with lower lung function [average reduction in FEV1 (forced expiratory volume in 1 sec) for a 10% increase in CO was 3.33 mL (95% CI: -0.86, -5.81)]. Lung function measures were not significantly associated with average postintervention personal CO concentrations. Our results provide further support for the effects of HAP exposures on airway inflammation. Further longitudinal research modeling continuous exposure to particulate matter against lung function will help us understand more fully the impact of HAP on COPD.

A Case of Massive Pleural Effusion: Pleurodesis by Bleomycin.

PubMed

Hasan, R; Khan, O S; Aftabuddin, M; Razzaque, A M; Chowdhury, G A

2016-04-01

Malignant pleural effusion is a common complication of primary and metastatic pleural malignancies. Pleurodesis for the management of malignant pleural effusion is intended to achieve symphysis between parietal and visceral pleura, and to prevent relapse of pleural effusion. Many chemical agents are tried to induce inflammation and damage of the pleural mesothelial layer to achieve this symphysis. Hemorrhagic pleural effusion, especially in the right hemithorax commonly occurs as presentation of primary and metastatic pleural malignancies. This case reports massive right-sided hemorrhagic pleural effusion as the sole manifestation of primary lung cancer in a 45 year old man. Patient attended our department of thoracic surgery complaining of cough, shortness of breath and right sided chest pain. A chest X-ray and chest computer tomography (CT) radiograph shows right sided massive pleural effusion. Right sided tube thoracotomy done. Pleural fluid study was done. Fluid for cytopathology was positive for malignant cell. Computed tomography guided fine needle aspiration cytology from right lung lesion was also done. Diagnosis was as small cell carcinoma. Pleural effusion resolved after 9(th) post operative day of chest tube insertion. Bleomycin pleurodesis was done. Day after pleurodesis intra thoracic tube was removed and patient was discharged from hospital on 10(th) Post operative day with an advice to attend the oncology department for further treatment. The protocol of tube thoracostomy and chemical pleurodesis was almost always successful in giving symptomatic relief of respiratory distress for a considerable period of time. However, chemical pleurodesis is not possible in all cases of malignant pleural effusion because it has got potential complication including death.

Proper size of endotracheal tube for cleft lip and palate patients and intubation outcomes.

PubMed

Abdollahifakhim, Shahin; Sheikhzadeh, Dariush; Shahidi, Nikzad; Nojavan, Gholamreza; Bayazian, Gholamreza; Aleshi, Hamideh

2013-05-01

The aim of the current study was to identify the proper size of endotracheal tube for intubation of cleft lip and palate patients and intubation outcomes in these patients. In this analytic cross-sectional study, 60 nonsyndromic cleft lip and palate patients were selected who had surgery between April 2010 and April 2012 at Pediatrics Hospital, Tabriz University of Medical Sciences, Iran. Demographic findings, previous admissions, and surgical history were registered. The proper tube size was measured by normal children formulas. Then tube size was confirmed by patients' minimum resistance to intubation, proper ventilation reported by anesthesiologist, and appropriate air leakage at an airway pressure of 15-20 cm H₂O. If intubation was unsuccessful then smaller size of endotracheal tube would be tried. Frequency of intubation trials and the biggest endotracheal tube size were recorded. Their average age, weight and height were 21.39 ± 4.95 months, 9.97 ± 1.18 kg and 74.30 ± 26.61 cm, respectively. The average tracheal tube size and frequency of intubation trials were 4.34 ± 0.78 and 1.63 ± 0.80, respectively. Seven cases required an endotracheal tube size smaller than the recommended size for that age including one case in unilateral cleft palate, three cases in unilateral cleft lip, one case in unilateral cleft lip and palate, and two cases in bilateral cleft lip and palate. Findings proved that considering subglottic stenosis incidence in these children, it is reasonable to determine the tube size for nonsyndromic cleft lip and palate patients by applying the currently available standards for normal children. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Recent Development Status of Stirling Type Pulse Tube Cryocooler for HTS

NASA Astrophysics Data System (ADS)

Hiratsuka, Y.; Nakano, K.; Kato, T.

2014-05-01

Sumitomo Heavy Industries, Ltd. (SHI) has been developing a high power stirling type pulse tube cryocooler. For the purpose of cooling high-temperature superconductor (HTS) devices, such as superconductor motor, SMES and current fault limiter, requested specifications from the devices to a cryocooler are compact size, light weight, high efficiency and high reliability. Especially, the cryocooler must be demanded COP > 0.1 in the efficiency. The experimental results of prototype pulse tube cryocooler were reported in June 2012 [1]. For an In-line type expander, the cooling capacity was 210 W at 77 K and the minimum temperature was 37 K when the compressor input power was 3.8 kW and the operating frequency was 49 Hz. Accordingly, COP was about 0.055. Moreover, for miniaturization a U type expander was tested and the performance is about 10 % less than that of an In-line type expander. After that, we have estimated that the cooling performance is influenced by the environment such as the effect of the pulse-tube inclination, the temperature and the flowing quantity of cooling water. The detailed results are reported in this paper.

Experimental investigation of spontaneous ignition and flame propagation at pressurized hydrogen release through tubes with varying cross-section.

PubMed

Duan, Qiangling; Xiao, Huahua; Gao, Wei; Gong, Liang; Sun, Jinhua

2016-12-15

An experimental investigation of spontaneous ignition and flame propagation at high-pressure hydrogen release via cylindrical tubes with varying cross-section is presented. Tubes with different transverse cross-sections are considered in the experiments: (1) local contraction, (2) local enlargement, (3) abrupt contraction, and (4) abrupt enlargement. The results show that the presence of the varying cross-section geometries can significantly promote the occurrence of spontaneous ignition. Compared to the tube with constant cross-section, the minimum pressure release needed for spontaneous ignition for the varying cross-sections tubes is considerably lower. Moreover, the initial ignition location is closer to the disk in the presence of varying cross-section geometries in comparison with straight channel. As the flame emerges from the outlet of the tube, the velocity of the flame front in the vicinity of the nozzle increases sharply. Then, a deflagration develops across the mixing zone of hydrogen/air mixture. The maximum deflagration overpressure increases linearly with the release pressure. Subsequently, a hydrogen jet flame is produced and evolves different shapes at different release stages. A fireball is formed after the jet flame spouts in the open air. Later, the fireball develops into a jet flame which shifts upward and continues to burn in the vertical direction. Copyright © 2016 Elsevier B.V. All rights reserved.

[Disturbed respiratory cycle accompanying hypoxic-ischemic encephalopathy].

PubMed

Saito, Yoshiaki; Masuko, Kaori; Kaneko, Kaori; Saito, Kazuyo; Chikumaru, Yuri; Iwamoto, Hiroko; Matsui, Akira; Kimura, Seiji

2005-09-01

We report the case of a 2-year-old boy who experienced total asphyxia at 4 months of age, and suffered abnormalities at specific phases of the respiratory cycle. The patient was bedridden due to severe tetraplegia and showed little response to external stimuli. He has been tube-fed since the initial asphyxia and a tracheotomy was performed after recurrent hypoxic episodes as a result of the respiratory dysfunction. Upon examination, his respiratory pattern was characterized by arrest during the inspiratory phase with a possible over-riding secondary inspiration. The respiratory pause at the inspiratory phase was markedly prolonged during an episode of pulmonary infection, resulting in recurrent cyanosis that necessitated artificial ventilation. The "second" inspiration typically occurred during the mid- or late-inspiratory phases, with this pattern often shown to be variable after epileptic seizures. The characteristic breathing of this patient suggested that difficulty in forming a normal respiratory cycle, other than during periods of hypoventilation or apnoea, could be a significant respiratory dysfunction following asphyxiation. Strategies for the management of such patients should be carefully designed after close observation of breathing patterns within the respiratory cycle, and with consideration for the influence of epileptic seizures and other inputs from somatic afferents.

Common and gender specific factors associated with one-year mortality in nursing home residents.

PubMed

Kiely, Dan K; Flacker, Jonathan M

2002-01-01

To identify common and gender-specific factors associated with mortality in two distinct nursing home (NH) populations: newly admitted (NA), and long-stay (LS) residents. A retrospective cohort study. NH facilities in the state of New York. A total of 59,080 NA female and 28,080 NA male NH residents, and 24,260 LS female and 8,928 LS male NH residents evaluated between June 1994 and December 1997 who were at least 65 years of age. Minimum Data Set information including measures of health, functional, cognitive, psychological, and social status. Multivariate proportional hazards regression results indicate that in NA residents, use of feeding tubes, bowel incontinence, and refuses fluids were associated with mortality in women only, whereas fever was associated with mortality in men only. Cancer and congestive heart failure (CHF) were more strongly associated with mortality in women than men. In LS residents, deterioration in communication, refuses fluids, use of indwelling catheters, and deterioration in cognition were associated with mortality in women but not men. Bedfast most of the time, use of new medications, and a balance problem were associated with mortality in men but not women. Shortness-of-breath was more strongly associated with mortality in women than men. In both NA and LS residents, although men and women share many common factors associated with mortality, each gender has some unique factors associated with mortality. Furthermore, the strength of some common factors is significantly different across genders. These readily available data could be useful in making medical decisions and advance directive planning, and in the development of quality improvement initiatives and mortality prediction models.

[Propofol for sedation in pediatric magnetic resonance imaging investigations].

PubMed

Reinhold, P; Graichen, B

1999-01-01

Magnetic Resonance Imaging requires immobilisation of the patients without excitement due to acoustic irritation. During childhood this is hardly to guarantee without anaesthesia or sedation. The problem is the magnetic field strength, which interferes with the monitoring devices and the anaesthesia machines interrupting the function and can produce thermal injury, but additionally the tools will cause image degradation. MR Imaging was done in 46 children with a mean age of 50.9 months (0.06 to 129) in a sedation with propofol during spontaneous breathing. The induction dose of propofol was 3.0 mg/kg bodyweight and the repetition dose was 1.0 mg/kg. During the radiological examination and the time of emergence the children were monitored with a MRI-compatible fiberoptic pulseoximeter (NONIN), a capnography by naso-pharyngeal canula (OHMEDA) and a noninvasive blood pressure oscillometer (CRITICON). The monitors were located outside the 0.5 Tesla area and were connected to the patient via extension tubing. Additionally there was a clinical observation by a present anaesthesiologist. In all children the investigation has been realized without any problem. Haemodynamics, ventilation and oxygenation have been in a normal range. Only 2 of the 186 sequences had to be repeated. After a mean time of investigation of 29 minutes (10 to 55) the emergence time until purposeful reaction was 7.7 minutes (5 to 20) and until full orientation was 13.4 minutes (5 to 30). This regime of sedation for children undergoing Magnetic Resonance Imaging is safe and suitable independent of age: there is a good control of vital functions, a minimum of side effects and a fine recovery characteristic with short times of emergence.

Investigation of the climatic extremes influence on the humane adaptive capacity by mass spectrometric analysis of exhaled breath condensate

NASA Astrophysics Data System (ADS)

Ryabokon, Anna; Larina, Irina; Kononikhin, Alexey; Starodubtceva, Nataliia; Popov, Igor; Nikolaev, Eugene; Varfolomeev, Sergey

Global climate change, which causes abnormal fluctuations in temperature and rainfall, has adverse effects on human health. Particularly people suffer with cardiovascular and respiratory system disease. Our research was concentrated on the changes in the regulation and adaptation systems of human organism related to hyperthermia and polluted air influence. Healthy individuals with the age from 22 to 45 years were isolated during 30 days in the ground based experimental facility located at Institute of medico-biological problems RAS (Moscow, Russia). In the ground based facility artificially climatic conditions of August, 2010 in Moscow were created. Exhaled breath condensate was collected before and after isolation by R-Tube collector, freeze dried, treated by trypsin and analyzed by nanoflow LC-MS/MS with a 7-Tesla LTQ-FT Ultra mass spectrometer (Thermo Electron, Bremen, Germany). Database search was performed using Mascot Server 2.2 software (Matrix Science, London, UK). Investigation of exhaled breath condensate (EBC) collected from participants of the 30 days isolation with hyper thermic and polluted air climate conditions was performed. After isolation reduction of the protein number was observed. Loss endothelial C receptor precursor - the main physiological anticoagulant - correlate with the clinical data of physicians to increase the propensity to thrombosis. Also COP9 signalosome protein, positive regulator of ubiquitin was identified in all EBC samples before isolation and was not detected for more than a half of donors after isolation. This phenomena may be due to violation of ubiquitin protection system of the cells from harmful proteins. During isolation the air was cleared from microdisperse particles.

Flow measurement in an in-vitro model of a single human alveolus

NASA Astrophysics Data System (ADS)

Chhabra, Sudhaker; Prasad, Ajay

2006-03-01

The alveolus is the smallest and most important unit in the acinar region of the human lung. It is responsible for gas exchange between the lungs and the blood. A complete knowledge of the airflow pattern in the acinar region is necessary to predict the transport and deposition of inhaled aerosol particles. Such knowledge will benefit the pharmaceutical community in its effort to deliver therapeutic aerosols for lung-specific as well as system-wide ailments. In addition, it can also help to assess the health effects of the toxic aerosols in the environment. We have constructed an in-vitro model of a single spherical alveolus on a circular tube. The alveolus is capable of expanding and contracting in phase with the oscillatory flow through the tube. Realistic breathing conditions are reproduced by matching Reynolds and Womersley numbers. Experimental methods such as particle imaging velocimetry and laser induced fluorescence are used to study the resulting flow patterns. In particular, recirculating flow within the alveolus, and the fluid exchange between the alveolar duct and the alveolus are important for better understanding the flow in the acinar region.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheng, Y.S.; Yeh, H.C.; Guilmette, R.A.

Very large and very small particles most often deposit in the nasal airways. Studies in airway models provide large data sets with which to evaluate the deposition mechanism, while in vivo deposition data are needed to validate results obtained with nasal models. Four adult male, nonsmoking, healthy human volunteers (ages 36-57 yr) participated in this study. Deposition was measured in each subject at constant flow rates of 4, 7.5, 10, and 20 L min{sup -1}. Monodisperse silver particles (5, 8, and 20 nm) and polystyrene latex particles (50 and 100 nm) were used. Bach subject held his breath for 30-60more » sec, during which time, the aerosol was drawn through the nasal airway and exhausted through a mouth tube. Aerosol concentrations in the intake and exhaust air were measured by an ultrafine condensation particle counter. The deposition efficiency in the nasal airway was calculated taking into account particle losses in the mask, mouth tube, and transport lines. Our results were consistent with the turbulent diffusional deposition model previously established from studies using nasal airway casts. 21 refs., 12 figs., 3 tabs.« less

Enhanced Raman Microprobe Imaging of Single-Wall Carbon Nanotubes

NASA Technical Reports Server (NTRS)

Hadjiev, V. G.; Arepalli, S.; Nikolaev, P.; Jandl, S.; Yowell, L.

2003-01-01

We explore Raman microprobe capabilities to visualize single wall carbon nanotubes (SWCNTs). Although this technique is limited to a micron scale, we demonstrate that images of individual SWCNTs, bundles or their agglomerates can be generated by mapping Raman active elementary excitations. We measured the Raman response from carbon vibrations in SWCNTs excited by confocal scanning of a focused laser beam. Carbon vibrations reveal key characteristics of SWCNTs as nanotube diameter distribution (radial breathing modes, RBM, 100-300 cm(exp -1)), presence of defects and functional groups (D-mode, 1300-1350 cm(exp -1)), strain and oxidation states of SWCNTs, as well as metallic or semiconducting character of the tubes encoded in the lineshape of the G-modes at 1520-1600 cm(exp - 1). In addition, SWCNTs are highly anisotropic scatterers. The Raman response from a SWCNT is maximal for incident light polarization parallel to the tube axis and vanishing for perpendicular directions. We show that the SWCNT bundle shape or direction can be determined, with some limitations, from a set of Raman images taken at two orthogonal directions of the incident light polarization.

Increased risk of snoring and adenotonsillectomy in children referred for tympanostomy tube insertion.

PubMed

Tauman, Riva; Derowe, Ari; Ophir, Orna; Greenfeld, Michal; Sivan, Yakov

2010-02-01

Eustachian tube dysfunction and sleep-disordered breathing (SDB) share common pathophysiologic mechanisms. Our objective was to investigate whether children referred for isolated TTI (tympanostomy tube insertion) are at increased risk for snoring and upper airway procedures. Telephone interviews to parents of children who underwent isolated TTI and to age- and gender-matched controls were conducted. Four hundred fifty-seven children were included in the study; 352 had isolated TTI (study group) and 105 children were controls. Twenty-two percent of children in the study group were reported to snore compared with 7.6% in the controls (p=0.001). Eighteen percent of children in the study group were reported to have undergone adenotonsillectomy compared with 4.8% in the controls (p=0.0005). Future SDB, i.e., either snoring or adenotonsillectomy following TTI, was found in 34% of children in the study group compared with 11% in the controls (p=0.0004). Children who underwent isolated TTI were at increased risk for future snoring (OR=3.4, CI: 1.6-7.2) and future adenotonsillectomy (OR=4.4, CI: 1.7-11.2). Children who undergo isolated TTI are at increased risk for snoring and for adenotonsillectomy. We suggest that these children be followed for symptoms of SDB on a scheduled basis to allow for early diagnosis and intervention. 2009 Elsevier B.V. All rights reserved.

Aruna Shanbaug: Is Her Demise the End of the Road for Legislation on Euthanasia in India?

PubMed

Kanchan, Tanuj; Atreya, Alok; Krishan, Kewal

2016-08-01

Aruna Ramachandra Shanbaug breathed her last after 42 years of being in a persistent vegetative state. Euthanasia in any form is not permitted in India and it was only in the year 2011 that a petition was filed in the court that urged the cessation of her force feeding with a nasogastric tube and the request for her peaceful death. What followed was a string of arguments and counter arguments relating to Euthanasia. The sad demise of Aruna Shanbaug is not the end of an individual, but may be the end of the road for clear cut guidelines and legislation on Euthanasia in India.

Correlation of Nasal Mucosal Temperature With Subjective Nasal Patency in Healthy Individuals

PubMed Central

Bailey, Ryan S.; Casey, Kevin P.; Pawar, Sachin S.; Garcia, Guilherme J. M.

2016-01-01

Importance Historically, otolaryngologists have focused on nasal resistance to airflow and minimum airspace cross-sectional area as objective measures of nasal obstruction using methods such as rhinomanometry and acoustic rhinometry. However, subjective sensation of nasal patency may be more associated with activation of cold receptors by inspired air than with respiratory effort. Objective To investigate whether subjective nasal patency correlates with nasal mucosal temperature in healthy subjects. Design, Setting, and Participants Twenty-two healthy adults were recruited for this study. Subjects first completed the Nasal Obstruction Symptom Evaluation (NOSE) and a unilateral visual analog scale (VAS) to quantify subjective nasal patency. A miniaturized thermocouple sensor was then used to record nasal mucosal temperature bilaterally in two locations along the nasal septum: at the vestibule and across from the inferior turbinate head. Results The range of temperature oscillations during the breathing cycle, defined as the difference between end-expiratory and end-inspiratory temperatures, was greater during deep breaths (ΔTexp-insp = 6.2 ± 2.6°C) than during resting breathing (ΔTexp-insp = 4.2 ± 2.3°C) in both locations (p < 10−13). Mucosal temperature measured at the right vestibule had a statistically significant correlation with both right-side VAS score (Pearson r = −0.55, p=0.0076) and NOSE score (Pearson r = −0.47, p=0.028). No other statistically significant correlations were found between mucosal temperature and subjective nasal patency scores. Nasal mucosal temperature was lower in the first cavity to be measured, which was the right cavity in all subjects. Conclusions and Relevance The greater mucosal temperature oscillations during deep breathing is consistent with the common experience that airflow sensation is enhanced during deep breaths, thus supporting the hypothesis that mucosal cooling plays a central role in nasal airflow sensation. A possible correlation was found between subjective nasal patency scores and nasal mucosal temperature, but our results were inconsistent. The higher temperature in the left cavity suggests that the sensor irritated the nasal mucosa, affecting the correlation between patency scores and mucosal temperature. Future studies should consider non-contact temperature sensors to prevent mucosa irritation. PMID:27918749

Exercise during Short-Term and Long-Term Continuous Exposure to Hypoxia Exacerbates Sleep-Related Periodic Breathing

PubMed Central

Tellez, Helio Fernandez; Morrison, Shawnda A.; Neyt, Xavier; Mairesse, Olivier; Piacentini, Maria Francesca; Macdonald-Nethercott, Eoin; Pangerc, Andrej; Dolenc-Groselj, Leja; Eiken, Ola; Pattyn, Nathalie; Mekjavic, Igor B.; Meeusen, Romain

2016-01-01

Study Objectives: Exposure to hypoxia elevates chemosensitivity, which can lead to periodic breathing. Exercise impacts gas exchange, altering chemosensitivity; however, interactions between sleep, exercise and chronic hypoxic exposure have not been examined. This study investigated whether exercise exacerbates sleep-related periodic breathing in hypoxia. Methods: Two experimental phases. Short-Term Phase: a laboratory controlled, group-design study in which 16 active, healthy men (age: 25 ± 3 y, height: 1.79 ± 0.06 m, mass: 74 ± 8 kg) were confined to a normobaric hypoxic environment (FIO2 = 0.139 ± 0.003, 4,000 m) for 10 days, after random assignment to a sedentary (control, CON) or cycle-exercise group (EX). Long-Term Phase: conducted at the Concordia Antarctic Research Station (3,800 m equivalent at the Equator) where 14 men (age: 36 ± 9 y, height: 1.77 ± 0.09 m, mass: 75 ± 10 kg) lived for 12–14 months, continuously confined. Participants were stratified post hoc based on self-reported physical activity levels. We quantified apnea-hypopnea index (AHI) and physical activity variables. Results: Short-Term Phase: mean AHI scores were significantly elevated in the EX group compared to CON (Night1 = CON: 39 ± 51, EX: 91 ± 59; Night10 = CON: 32 ± 32, EX: 92 ± 48; P = 0.046). Long-Term Phase: AHI was correlated to mean exercise time (R2 = 0.4857; P = 0.008) and the coefficient of variation in night oxyhemoglobin saturation (SpO2; R2 = 0.3062; P = 0.049). Conclusions: Data indicate that exercise (physical activity) per se affects night SpO2 concentrations and AHI after a minimum of two bouts of moderate-intensity hypoxic exercise, while habitual physical activity in hypobaric hypoxic confinement affects breathing during sleep, up to 13+ months' duration Citation: Tellez HF, Morrison SA, Neyt X, Mairesse O, Piacentini MF, Macdonald-Nethercott E, Pangerc A, Dolenc-Groselj L, Eiken O, Pattyn N, Mekjavic IB, Meeusen R. Exercise during short-term and long-term continuous exposure to hypoxia exacerbates sleep-related periodic breathing. SLEEP 2016;39(4):773–783. PMID:26951389

The NASA, Marshall Space Flight Center drop tube user's manual

NASA Technical Reports Server (NTRS)

Rathz, Thomas J.; Robinson, Michael B.

1990-01-01

A comprehensive description of the structural and instrumentation hardware and the experimental capabilities of the 105-meter Marshall Space Flight Center Drop Tube Facility is given. This document is to serve as a guide to the investigator who wishes to perform materials processing experiments in the Drop Tube. Particular attention is given to the Tube's hardware to which an investigator must interface to perform experiments. This hardware consists of the permanent structural hardware (with such items as vacuum flanges), and the experimental hardware (with the furnaces and the sample insertion devices). Two furnaces, an electron-beam and an electromagnetic levitator, are currently used to melt metallic samples in a process environment that can range from 10(exp -6) Torr to 1 atmosphere. Details of these furnaces, the processing environment gases/vacuum, the electrical power, and data acquisition capabilities are specified to allow an investigator to design his/her experiment to maximize successful results and to reduce experimental setup time on the Tube. Various devices used to catch samples while inflicting minimum damage and to enhance turnaround time between experiments are described. Enough information is provided to allow an investigator who wishes to build his/her own furnace or sample catch devices to easily interface it to the Tube. The experimental instrumentation and data acquisition systems used to perform pre-drop and in-flight measurements of the melting and solidification process are also detailed. Typical experimental results are presented as an indicator of the type of data that is provided by the Drop Tube Facility. A summary bibliography of past Drop Tube experiments is provided, and an appendix explaining the noncontact temperature determination of free-falling drops is provided. This document is to be revised occasionally as improvements to the Facility are made and as the summary bibliography grows.

The Effects of Boundary Conditions and Friction on the Helical Buckling of Coiled Tubing in an Inclined Wellbore

PubMed Central

Ai, Zhijiu; Sun, Xu; Fu, Biwei

2016-01-01

Analytical buckling models are important for down-hole operations to ensure the structural integrity of the drill string. A literature survey shows that most published analytical buckling models do not address the effects of inclination angle, boundary conditions or friction. The objective of this paper is to study the effects of boundary conditions, friction and angular inclination on the helical buckling of coiled tubing in an inclined wellbore. In this paper, a new theoretical model is established to describe the buckling behavior of coiled tubing. The buckling equations are derived by applying the principles of virtual work and minimum potential energy. The proper solution for the post-buckling configuration is determined based on geometric and natural boundary conditions. The effects of angular inclination and boundary conditions on the helical buckling of coiled tubing are considered. Many significant conclusions are obtained from this study. When the dimensionless length of the coiled tubing is greater than 40, the effects of the boundary conditions can be ignored. The critical load required for helical buckling increases as the angle of inclination and the friction coefficient increase. The post-buckling behavior of coiled tubing in different configurations and for different axial loads is determined using the proposed analytical method. Practical examples are provided that illustrate the influence of the angular inclination on the axial force. The rate of change of the axial force decreases with increasing angular inclination. Moreover, the total axial friction also decreases with an increasing inclination angle. These results will help researchers to better understand helical buckling in coiled tubing. Using this knowledge, measures can be taken to prevent buckling in coiled tubing during down-hole operations. PMID:27649535

The Effects of Boundary Conditions and Friction on the Helical Buckling of Coiled Tubing in an Inclined Wellbore.

PubMed

Gong, Yinchun; Ai, Zhijiu; Sun, Xu; Fu, Biwei

2016-01-01

Analytical buckling models are important for down-hole operations to ensure the structural integrity of the drill string. A literature survey shows that most published analytical buckling models do not address the effects of inclination angle, boundary conditions or friction. The objective of this paper is to study the effects of boundary conditions, friction and angular inclination on the helical buckling of coiled tubing in an inclined wellbore. In this paper, a new theoretical model is established to describe the buckling behavior of coiled tubing. The buckling equations are derived by applying the principles of virtual work and minimum potential energy. The proper solution for the post-buckling configuration is determined based on geometric and natural boundary conditions. The effects of angular inclination and boundary conditions on the helical buckling of coiled tubing are considered. Many significant conclusions are obtained from this study. When the dimensionless length of the coiled tubing is greater than 40, the effects of the boundary conditions can be ignored. The critical load required for helical buckling increases as the angle of inclination and the friction coefficient increase. The post-buckling behavior of coiled tubing in different configurations and for different axial loads is determined using the proposed analytical method. Practical examples are provided that illustrate the influence of the angular inclination on the axial force. The rate of change of the axial force decreases with increasing angular inclination. Moreover, the total axial friction also decreases with an increasing inclination angle. These results will help researchers to better understand helical buckling in coiled tubing. Using this knowledge, measures can be taken to prevent buckling in coiled tubing during down-hole operations.

Multispecies breath analysis faster than a single respiratory cycle by optical-feedback cavity-enhanced absorption spectroscopy

NASA Astrophysics Data System (ADS)

Ventrillard-Courtillot, Irene; Gonthiez, Thierry; Clerici, Christine; Romanini, Daniel

2009-11-01

We demonstrate a first application, of optical-feedback cavity-enhanced absorption spectroscopy (OF-CEAS) to breath analysis in a medical environment. Noninvasive monitoring of trace species in exhaled air was performed simultaneous to spirometric measurements on patients at Bichat Hospital (Paris). The high selectivity of the OF-CEAS spectrometer and a time response of 0.3 s (limited by sample flow rate) allowed following the evolution of carbon monoxide and methane concentrations during individual respiratory cycles, and resolving variations among different ventilatory patterns. The minimum detectable absorption on this time scale is about 3×10-10 cm-1. At the working wavelength of the instrument (2.326 μm), this translates to concentration detection limits of ~1 ppbv (45 picomolar, or ~1.25 μg/m3) for CO and 25 ppbv for CH4, well below concentration values found in exhaled air. This same instrument is also able to provide measurement of NH3 concentrations with a detection limit of ~10 ppbv however, at present, memory effects do not allow its measurement on fast time scales.

Impact of different rectangular wires on torsional expression of different sizes of buccal tube.

PubMed

Ajami, Shabnam; Boroujeni, Afshar-Rasti

2018-01-01

Torsions in rectangular wires are the essential part of corrections in the finishing stage of treatment. Moreover the greatest amounts of torques are applied in the molar areas. a clinically effective moment is between 5 and 20 Nmm. In this study we have decided to evaluate the impact of different tube sizes and different dimensions of wires with different modulus of elasticities on the amount torsional bond strength of molar tubes. 60 human impacted molar teeth were collected. A buccal tube was bonded on the buccal surface of all the samples by using light cured adhesive resin. After that, the teeth were mounted in a hard acrylic block. According to the size of buccal tube and the rectangular wires to be tested 4 groups will be designed. Torsional force was applied by instron machine. The torque angle at 5Nmm and at 20Nmm point will be calculated: which means, how many degrees of torque is required to reach the maximum 20Nmm moment from the minimum 5Nmm.One-way ANOVA was used to compare torque angle in all of the groups. The least amount of clinically significant angle was 2.2 ᵒ in the 0.017×0.025 SS and the largest amount of it was 23.7 ᵒ in the 0.017×0.025 TMA in 0.018×0.025 slot molar tube. But, this angle was 19.9 ᵒand 13.6 ᵒ in 0.019×0.025 SS and 0.019×0.025 TMA archwire in 0.022×0.028 molar tube. The 0.017×0.025 SS archwire in 0.018×0.025 molar tube had the lowest clinically significant angle. The largest amount was seen in group 0.017×0.025 TMA in 0.018×0.025 slot molar tube. Key words: Torsional efficacy, rectangular wires, buccal tubes, torque angle.

Case Series: Keratolimbal Allograft as a Patch Graft for Glaucoma Drainage Devices.

PubMed

Ahmed, Sarah F; Schmutz, Mason; Mosaed, Sameh

2017-09-01

Tube exposure remains one of the most common complications after glaucoma drainage device (GDD) implantation, despite various types of patch grafts available today. We present a 4 patient case series following the effectivity of the keratolimbal allograft (KLAL) as a patch graft for cases of tube exposure. Given its inherent population of stem cells, our hypothesis was that this highly replicative, biological tissue would provide an adequate means of glaucoma tube coverage. The subset of patients chosen for the KLAL patch graft all had a history of abnormally scarred conjunctiva or thin sclera. The aim of utilizing the KLAL patch with its associated donor conjunctival and scleral ring was also to provide additional reinforcement and adequate tube coverage in the setting of compromised native tissue. Four patients comprised of 2 males and 2 females with a minimum postoperative period of 12 months. All GDDs were initially implanted with a limbal-based incision using either Ahmed glaucoma valve or Baerveldt drainage implant. Three of the 4 patients received the KLAL patch graft after tube exposure with scleral patch graft and 1 patient received KLAL as the primary graft during initial tube placement. Two of the 4 eyes experienced tube re-exposure postoperatively at 2 and 3 months, respectively. Both of these cases had a history of prior tube exposure after scleral patch graft and both were tubes placed in the pars plana. Interestingly, the patients with failed grafts were younger with a history of more ocular surgeries as compared with the patients with graft viable eyes. Through our case series, we found that the KLAL utilized as a patch graft over GDD tubes has the potential for favorable outcomes in certain subtypes of eyes. Although further large scale investigation will be necessary to better define the risk factors associated with graft failure, proving the graft's viability is a crucial first step.

Impact of different rectangular wires on torsional expression of different sizes of buccal tube

PubMed Central

Boroujeni, Afshar-Rasti

2018-01-01

Background Torsions in rectangular wires are the essential part of corrections in the finishing stage of treatment. Moreover the greatest amounts of torques are applied in the molar areas. a clinically effective moment is between 5 and 20 Nmm. In this study we have decided to evaluate the impact of different tube sizes and different dimensions of wires with different modulus of elasticities on the amount torsional bond strength of molar tubes. Material and Methods 60 human impacted molar teeth were collected. A buccal tube was bonded on the buccal surface of all the samples by using light cured adhesive resin. After that, the teeth were mounted in a hard acrylic block. According to the size of buccal tube and the rectangular wires to be tested 4 groups will be designed. Torsional force was applied by instron machine. The torque angle at 5Nmm and at 20Nmm point will be calculated: which means, how many degrees of torque is required to reach the maximum 20Nmm moment from the minimum 5Nmm.One-way ANOVA was used to compare torque angle in all of the groups. Results The least amount of clinically significant angle was 2.2 ᵒ in the 0.017×0.025 SS and the largest amount of it was 23.7 ᵒ in the 0.017×0.025 TMA in 0.018×0.025 slot molar tube. But, this angle was 19.9 ᵒand 13.6 ᵒ in 0.019×0.025 SS and 0.019×0.025 TMA archwire in 0.022×0.028 molar tube. Conclusions The 0.017×0.025 SS archwire in 0.018×0.025 molar tube had the lowest clinically significant angle. The largest amount was seen in group 0.017×0.025 TMA in 0.018×0.025 slot molar tube. Key words: Torsional efficacy, rectangular wires, buccal tubes, torque angle. PMID:29670712

21 CFR 800.20 - Patient examination gloves and surgeons' gloves; sample plans and test method for leakage defects...

Code of Federal Regulations, 2010 CFR

2010-04-01

... examination and by a water leak test method, using 1,000 milliliters (ml) of water. (i) Units examined. Each... inches up the fill tube.) (iii) Leak test examination. Immediately after adding the water, examine the glove for water leaks. Do not squeeze the glove; use only minimum manipulation to spread the fingers to...

Analysis of the interplay between neurochemical control of respiration and upper airway mechanics producing upper airway obstruction during sleep in humans.

PubMed

Longobardo, G S; Evangelisti, C J; Cherniack, N S

2008-02-01

Increased loop gain (a function of both controller gain and plant gain), which results in instability in feedback control, is of major importance in producing recurrent central apnoeas during sleep but its role in causing obstructive apnoeas is not clear. The purpose of this study was to investigate the role of loop gain in producing obstructive sleep apnoeas. Owing to the complexity of factors that may operate to produce obstruction during sleep, we used a mathematical model to sort them out. The model used was based on our previous model of neurochemical control of breathing, which included the effects of chemical stimuli and changes in alertness on respiratory pattern generator activity. To this we added a model of the upper airways that contained a narrowed section which behaved as a compressible elastic tube and was tethered during inspiration by the contraction of the upper airway dilator muscles. These muscles in the model, as in life, responded to changes in hypoxia, hypercapnia and alertness in a manner similar to the action of the chest wall muscles, opposing the compressive action caused by the negative intraluminal pressure generated during inspiration which was magnified by the Bernoulli Effect. As the velocity of inspiratory airflow increased, with sufficiently large increase in airflow velocity, obstruction occurred. Changes in breathing after sleep onset were simulated. The simulations showed that increases in controller gain caused the more rapid onset of obstructive apnoeas. Apnoea episodes were terminated by arousal. With a constant controller gain, as stiffness decreased, obstructed breaths appeared and periods of obstruction recurred longer after sleep onset before disappearing. Decreased controller gain produced, for example, by breathing oxygen eliminated the obstructive apnoeas resulting from moderate reductions in constricted segment stiffness. This became less effective as stiffness was reduced more. Contraction of the upper airway muscles with hypercapnia and hypoxia could prevent obstructed apnoeas with moderate but not with severe reductions in stiffness. Increases in controller gain, as might occur with hypoxia, converted obstructive to central apnoeas. Breathing CO2 eliminated apnoeas when the activity of the upper airway muscles was considered to change as a function of CO2 to some exponent. Low arousal thresholds and increased upper airway resistance are two factors that promoted the occurrence and persistence of obstructive sleep apnoeas.

Automatic tube current modulation technique for multidetector CT: is it effective with a 64-detector CT?

PubMed

Funama, Yoshinori; Awai, Kazuo; Hatemura, Masahiro; Shimamura, Masamitchi; Yanaga, Yumi; Oda, Seitaro; Yamashita, Yasuyuki

2008-01-01

To investigate whether it is possible to obtain adequate images at uniform image noise levels and reduced radiation exposure with our automatic tube current modulation (ATCM) technique for 64-detector CT. The study population consisted of 64 patients with known or suspected lung or abdominal disease. We used a 64-detector CT scanner (LightSpeed VCT, GE Healthcare, Waukesha, WI, USA) and a combined angular and longitudinal tube current modulation technique (Smart mA, GE Healthcare, Waukesha, WI, USA) to examine 34 patients. The scanning parameters were identical; the minimum and maximum tube current thresholds were 50 and 800 mA, respectively. For study of the constant tube current technique, 30 additional patients were examined at 350 mA. The CT number and image noise (SD of the CT number) were measured in the 64 patients at six levels, i.e., the center of the left ventricle, the liver dome, the porta hepatis, the center of the spleen and the right and left renal pelvis. When we used the ATCM technique, the mean image noise ranged from 8.40 at the center of the left ventricle to 11.31 at the porta hepatis; the mean tube current ranged from 105.9 mAs at the center of the left ventricle to 169.6 mAs at the center of the spleen. The mean dose reduction rate per constant tube current at 175 mAs ranged from 3.1 to 39.5%. By use of the ATCM technique, it is possible to maintain a constant image noise level with a 64-detector CT.

On limitations of laser-induced fluorescence diagnostics for xenon ion velocity distribution function measurements in Hall thrusters

NASA Astrophysics Data System (ADS)

Romadanov, I.; Raitses, Y.; Diallo, A.; Hara, K.; Kaganovich, I. D.; Smolyakov, A.

2018-03-01

Hall thruster operation is characterized by strong breathing oscillations of the discharge current, the plasma density, the temperature, and the electric field. Probe- and laser-induced fluorescence (LIF) diagnostics were used to measure temporal variations of plasma parameters and the xenon ion velocity distribution function (IVDF) in the near-field plasma plume in regimes with moderate (<18%) external modulations of applied DC discharge voltage at the frequency of the breathing mode. It was shown that the LIF signal collapses while the ion density at the same location is finite. The proposed explanation for this surprising result is based on a strong dependence of the excitation cross-section of metastables on the electron temperature. For large amplitudes of oscillations, the electron temperature at the minimum enters the region of very low cross-section (for the excitation of the xenon ions); thus, significantly reducing the production of metastable ions. Because the residence time of ions in the channel is generally shorter than the time scale of breathing oscillations, the density of the excited ions outside the thruster is low and they cannot be detected. In the range of temperature of oscillations, the ionization cross-section of xenon atoms remains sufficiently large to sustain the discharge. This finding suggests that the commonly used LIF diagnostic of xenon IVDF can be subject to large uncertainties in the regimes with significant oscillations of the electron temperature, or other plasma parameters.

Sensitive detection of nitric oxide using a 5.26 μm external cavity quantum cascade laser based QEPAS sensor

NASA Astrophysics Data System (ADS)

Tittel, Frank K.; Dong, Lei; Lewicki, Rafal; Lee, George; Peralta, Adjani; Spagnolo, Vincenzo

2012-01-01

The development and performance of a continuous wave (CW), thermoelectrically cooled (TEC) external cavity quantum cascade laser (EC-QCL) based sensor for quantitative measurements of nitric oxide (NO) concentrations in exhaled breath will be reported. Human breath contains ~ 400 different chemical species, usually at ultra low concentration levels, which can serve as biomarkers for the identification and monitoring of human diseases or wellness states. By monitoring exhaled NO concentration levels, a fast non-invasive diagnostic method for treatment of patients with asthma and chronic obstructive pulmonary disease (COPD) is feasible. The NO concentration measurements are performed with a 2f wavelength modulation based quartz enhanced photoacoustic spectroscopy (QEPAS) technique, which is very suitable for real time breath measurements, due to the fast gas exchange inside a compact QEPAS gas cell (<5 mm3 typical volume). In order to target the optimal interference free NO R (6.5) absorption doublet at 1900.08 cm-1(λ~5.263 μm) a Daylight Solutions Inc. widely tunable, mode-hop free 100 mW EC-QCL was used. The sensor reference channel includes a 10 cm long reference cell, filled with a 0.5% NO in N2 at 150 Torr, which is used for line-locking purpose. A minimum detection limit (1σ) for the EC-QCL based line locked NO sensor is ~5 ppbv with a 1 sec update time by a custom built control QCL compatible electronics unit.

Respiratory reflexes in spontaneously breathing anesthetized dogs in response to nasal administration of sevoflurane, isoflurane, or halothane.

PubMed

Mutoh, T; Kanamaru, A; Suzuki, H; Tsubone, H; Nishimura, R; Sasaki, N

2001-03-01

To characterize respiratory reflexes elicited by nasal administration of sevoflurane (Sevo), isoflurane (Iso), or halothane (Hal) in anesthetized dogs. 8 healthy Beagles. A permanent tracheostomy was created in each dog. Two to 3 weeks later, dogs were anesthetized by IV administration of thiopental and alpha-chloralose. Nasal passages were isolated such that inhalant anesthetics could be administered to the nasal passages while the dogs were breathing 100% O2 via the tracheostomy. Respiratory reflexes in response to administration of each anesthetic at 1.2 and 2.4 times the minimum alveolar concentration (MAC) and the full vaporizer setting (5%) were recorded. Reflexes in response to administration of 5% of each anesthetic also were recorded following administration of lidocaine to the nasal passages. Nasal administration of Sevo, Iso, and Hal induced an immediate ventilatory response characterized by a dose-dependent increase in expiratory time and a resulting decrease in expired volume per unit of time. All anesthetics had a significant effect, but for Sevo, the changes were smaller in magnitude. Responses to administration of each anesthetic were attenuated by administration of lidocaine to the nasal passages. Nasal administration of Sevo at concentrations generally used for mask induction of anesthesia induced milder reflex inhibition of breathing, presumably via afferent neurons in the nasal passages, than that of Iso or Hal. Respiratory reflexes attributable to stimulation of the nasal passages may contribute to speed of onset and could promote a smoother induction with Sevo, compared with Iso or Hal.

Technique for enhancing the power output of an electrostatic generator employing parametric resonance

DOEpatents

Post, Richard F.

2016-02-23

A circuit-based technique enhances the power output of electrostatic generators employing an array of axially oriented rods or tubes or azimuthal corrugated metal surfaces for their electrodes. During generator operation, the peak voltage across the electrodes occurs at an azimuthal position that is intermediate between the position of minimum gap and maximum gap. If this position is also close to the azimuthal angle where the rate of change of capacity is a maximum, then the highest rf power output possible for a given maximum allowable voltage at the minimum gap can be attained. This rf power output is then coupled to the generator load through a coupling condenser that prevents suppression of the dc charging potential by conduction through the load. Optimized circuit values produce phase shifts in the rf output voltage that allow higher power output to occur at the same voltage limit at the minimum gap position.

Atom Skimmers and Atom Lasers Utilizing Them

NASA Technical Reports Server (NTRS)

Hulet, Randall; Tollett, Jeff; Franke, Kurt; Moss, Steve; Sackett, Charles; Gerton, Jordan; Ghaffari, Bita; McAlexander, W.; Strecker, K.; Homan, D.

2005-01-01

Atom skimmers are devices that act as low-pass velocity filters for atoms in thermal atomic beams. An atom skimmer operating in conjunction with a suitable thermal atomic-beam source (e.g., an oven in which cesium is heated) can serve as a source of slow atoms for a magneto-optical trap or other apparatus in an atomic-physics experiment. Phenomena that are studied in such apparatuses include Bose-Einstein condensation of atomic gases, spectra of trapped atoms, and collisions of slowly moving atoms. An atom skimmer includes a curved, low-thermal-conduction tube that leads from the outlet of a thermal atomic-beam source to the inlet of a magneto-optical trap or other device in which the selected low-velocity atoms are to be used. Permanent rare-earth magnets are placed around the tube in a yoke of high-magnetic-permeability material to establish a quadrupole or octupole magnetic field leading from the source to the trap. The atoms are attracted to the locus of minimum magnetic-field intensity in the middle of the tube, and the gradient of the magnetic field provides centripetal force that guides the atoms around the curve along the axis of the tube. The threshold velocity for guiding is dictated by the gradient of the magnetic field and the radius of curvature of the tube. Atoms moving at lesser velocities are successfully guided; faster atoms strike the tube wall and are lost from the beam.

Air-Q® versus LMA Fastrach™ for fiberoptic-guided intubation: A randomized cross-over manikin trial.

PubMed

Portas, M; Canal, M I; Barrio, M; Alonso, M; Cabrerizo, P; López-Gil, M; Zaballos, M

2018-03-01

Airway management is still a major cause of anesthesia-associated morbidity and mortality. Supraglottic devices are recommended in difficult airway management guidelines. The aim of this study was to compare the performance of the Air-Q ® and the LMA Fastrach™ for fiberoptic guided tracheal intubation. Thirty-three anesthesia trainees participated in this randomized crossover study. Time to insert the dedicated airways (insertion of the airway into the manikin and delivery of two breaths), time to tracheal intubation (fiberoptic-guided tracheal intubation), time to remove the dedicated airway (removal of the Air-Q ® /LMA Fastrach™ over the tracheal tube) and the opinion of the ease of use of the anesthesia trainees were measured. There was 100% success rate for tracheal intubation with both devices on the first attempt. Time to insert the dedicated device and deliver two breaths was 10±3s for the Air-Q ® and 11±3s for the LMA Fastrach™, P=.07. Time taken to intubate the trachea was shorter with the air-Q ® , 38±15 s, than with the LMA Fastrach™, 47±19s, P=.017. Overall procedure time was significantly shorter with the Air-Q ® as compared with the LMA Fastrach™, with a mean time of 74±21s and 87±28s respectively, P=.002. Air-Q ® removal was considered easier than LMA Fastrach™ removal, P=.005. There were no tube dislodgements during the removal of the dedicated airways. Inexperienced anesthesia residents can perform fiberoptic-guided intubation through Air-Q ® and LMA Fastrach™ in a clinically acceptable time with high success. Copyright © 2017 Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor. Publicado por Elsevier España, S.L.U. All rights reserved.

Diagnosis and management of the patulous eustachian tube.

PubMed

Poe, Dennis S

2007-08-01

The patulous eustachian tube (ET) seems to be caused by a longitudinal concave defect in the mucosal valve at the superior aspect of its anterolateral wall and causes troublesome autophony of one's own voice and breathing sounds. Patulous ET reconstruction was evaluated to analyze whether submucosal graft implantation to fill in the concavity within the patulous tubal valve may produce lasting relief of symptoms. Prospective trial. Tertiary referral center, ambulatory surgery. Fourteen ETs in 11 adults with 1 or more years of confirmed continuous patulous ET symptoms refractory to medical care. Endoluminal patulous ET reconstruction was performed in 14 separate cases using a combined endoscopic transnasal and transoral approach under general anesthesia. A submucosal flap was raised along the anterolateral wall of the tubal lumen up to the valve and mobilized superiorly off of the basisphenoid. The pocket was filled with autologous cartilage graft or Alloderm implant, restoring the normal convexity and competence to the mucosal lumen valve. Autophony symptoms were scored as 1) complete relief; 2) significant improvement, satisfied; 3)significant improvement, dissatisfied; 4) unchanged; or 5)worse. All 14 cases reported immediate complete relief of autophony. Results with an average follow-up of 15.8 months are as follows: 1 (7%) case had complete relief; 5 (36%) had significant improvement, satisfied; 7 (50%) had significant improvement, dissatisfied; and 1 (7%) was unchanged. There were no complications. Correlation between patulous ET and other conditions was strongest with previous tubal dysfunction. Autophony of voice, but not breathing sounds, was also found to be experienced by 17 (94%) of 18 patients with superior semicircular canal dehiscence syndrome and could be easily mistaken for patulous ET autophony. Patulous ET seems to be caused by a concave defect in the tubal valve's anterolateral wall. Submucosal graft implantation to restore the normal convexity to the valve wall seems to provide lasting relief of symptoms. Long-term study is needed. It is important to differentiate between the autophony of semicircular canal dehiscence syndrome and patulous ET.

Evaluation of Endotracheal Tube Scraping on Airway Resistance.

PubMed

Scott, J Brady; Dubosky, Meagan N; Vines, David L; Sulaiman, Adewunmi S; Jendral, Kyle R; Singh, Gagan; Patel, Ankeet; Kaplan, Carl A; Gurka, David P; Balk, Robert A

2017-11-01

Spontaneous breathing trials (SBTs) are used to assess the readiness for discontinuation of mechanical ventilation. When airway resistance (R aw ) is elevated, the imposed work of breathing can lead to prolongation of mechanical ventilation. Biofilm and mucus build-up within the endotracheal tube (ETT) can increase R aw . Scraping the ETT can remove the biofilm build-up and decrease mechanical R aw . The primary aim of this study was to evaluate the impact of ETT scraping on R aw . The secondary aim was to determine whether decreasing R aw would impact subsequent SBT success. Intubated, mechanically ventilated subjects were enrolled if they failed an SBT and had an R aw of > 10 cm H 2 O/L/s. SBT failure was based on institutional guidelines, and R aw was calculated by subtracting the difference between the measured peak and plateau pressures using a square flow waveform with an inspiratory flow set at 60 L/min. The endOclear device was inserted into the ETT and withdrawn per manufacturer's guidelines. Scraping was repeated until the ETT was cleared. Change in R aw was compared pre- and post-ETT scraping using a paired t test. A Mann-Whitney U test evaluated the difference in percentage change in R aw between SBT groups. Twenty-nine subjects completed the study. The mean pre- and post-ETT scraping R aw values were 15.17 ± 3.83 and 12.05 ± 3.19 cm H 2 O/L/s, respectively ( P < .001). Subsequent SBT success was 48%; however, there was no difference in percentage change in R aw between subsequent passed SBT (18.61% [interquartile range 8.90-33.93%]) and failed SBT (23.88% [interquartile range 0.00-34.80%]), U = 78.5, z = -0.284, P = .78. No adverse events were noted with ETT scraping. This study demonstrated that ETT scraping can reduce R aw . The decrease in R aw post-ETT scraping did not affect subsequent SBT success. Copyright © 2017 by Daedalus Enterprises.

Quiet Short-Haul Research Airplane (QSRA) model select panel functional description

NASA Technical Reports Server (NTRS)

Watson, D. M.

1982-01-01

The QSRA, when equipped with programmable color cathode ray tube displays, a head up display, a general purpose digital computer and a microwave landing system receiver, will provide a capability to do handling qualities studies and terminal area operating systems experiments as well as to enhance an experimenter's ability to obtain repeatable aircraft performance data. The operating systems experiments include the capability to generate minimum fuel approach and departure paths and to conduct precision approaches to a STOLport runway. The mode select panel is designed to provide both the flexibility needed for a variety of flight test experiments and the minimum workload operation required by pilots flying into congested terminal traffic areas.

Developments on GM-Type Pulse Tube Cryorefrigerators with Large Cooling Power

NASA Astrophysics Data System (ADS)

Köttig, T.; Waldauf, A.; Thürk, M.; Seidel, P.

2004-06-01

Over the past several years the authors have participated in basic and prototype developments of four valve pulse tube refrigerators (FVPTR). Systematic studies have been carried out to characterize the basics of energy transport mechanisms, the flow distribution and loss mechanisms of this type of pulse tube refrigerator (PTR) with its active type of phase shifting. Based on the comprehension of these phenomena, several prototypes have been built and optimized for various applications. Recently a single-stage PTR in coaxial arrangement has been designed for maximum refrigeration power in the temperature range between 20 and 80 K limited by an available electrical input power of 7 kW. To reach this goal we used lead screens in the coldest part of the regenerator instead of spheres in order to decrease the pressure drop. The improvement of the regenerator prevents the reported fact that at higher temperatures the performance of a pulse tube with a regenerator partially filled with lead spheres can even be worse than a regenerator totally made of stainless steel. At the moment the cooler provides a cooling power of 120 W@74 K and 40 W@34 K. The minimum no-load temperature achieved is 18.6 K.

Online fault diagnostics and testing of area gamma radiation monitor using wireless network

NASA Astrophysics Data System (ADS)

Reddy, Padi Srinivas; Kumar, R. Amudhu Ramesh; Mathews, M. Geo; Amarendra, G.

2017-07-01

Periodical surveillance, checking, testing, and calibration of the installed Area Gamma Radiation Monitors (AGRM) in the nuclear plants are mandatory. The functionality of AGRM counting electronics and Geiger-Muller (GM) tube is to be monitored periodically. The present paper describes the development of online electronic calibration and testing of the GM tube from the control room. Two electronic circuits were developed, one for AGRM electronic test and another for AGRM detector test. A dedicated radiation data acquisition system was developed using an open platform communication server and data acquisition software. The Modbus RTU protocol on ZigBee based wireless communication was used for online monitoring and testing. The AGRM electronic test helps to carry out the three-point electronic calibration and verification of accuracy. The AGRM detector test is used to verify the GM threshold voltage and the plateau slope of the GM tube in-situ. The real-time trend graphs generated during these tests clearly identified the state of health of AGRM electronics and GM tube on go/no-go basis. This method reduces the radiation exposures received by the maintenance crew and facilitates quick testing with minimum downtime of the instrument.

Gaseous detonation initiation via wave implosion

NASA Astrophysics Data System (ADS)

Jackson, Scott Irving

Efficient detonation initiation is a topic of intense interest to designers of pulse detonation engines. This experimental work is the first to detonate propane-air mixtures with an imploding detonation wave and to detonate a gas mixture with a non-reflected, imploding shock. In order to do this, a unique device has been developed that is capable of generating an imploding toroidal detonation wave inside of a tube from a single ignition point without any obstruction to the tube flow path. As part of this study, an initiator that creates a large-aspect-ratio planar detonation wave in gas-phase explosive from a single ignition point has also been developed. The effectiveness of our initiation devices has been evaluated. The minimum energy required by the imploding shock for initiation was determined to scale linearly with the induction zone length, indicating the presence of a planar initiation mode. The imploding toroidal detonation initiator was found to be more effective at detonation initiation than the imploding shock initiator, using a comparable energy input to that of current initiator tubes.

Effect Of Water On Permeation By Hydrogen

NASA Technical Reports Server (NTRS)

Tomazic, William A.; Hulligan, David

1988-01-01

Water vapor in working fluid equilibrates with permeability-reducing oxides in metal parts. Report describes study of effects of water on permeation of heater-head tubes by hydrogen in Stirling engine. Experiments performed to determine minimum concentration of oxygen and/or oxygen-bearing gas maintaining oxide coverage adequate for low permeability. Tests showed 750 ppm or more of water effective in maintaining stable, low permeability.

Dissipative particle dynamics simulations of deformation and aggregation of healthy and diseased red blood cells in a tube flow

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ye, Ting; Phan-Thien, Nhan, E-mail: Nhan@nus.edu.sg; Khoo, Boo Cheong

In this paper, we report simulation results assessing the deformation and aggregation of mixed healthy and malaria-infected red blood cells (RBCs) in a tube flow. A three dimensional particle model based on Dissipative Particle Dynamics (DPD) is developed to predict the tube flow containing interacting cells. The cells are also modelled by DPD, with a Morse potential to characterize the cell-cell interaction. As validation tests, a single RBC in a tube flow and two RBCs in a static flow are simulated to examine the cell deformation and intercellular interaction, respectively. The study of two cells, one healthy and the othermore » malaria-infected RBCs in a tube flow demonstrates that the malaria-infected RBC (in the leading position along flow direction) has different effects on the healthy RBC (in the trailing position) at the different stage of parasite development or at the different capillary number. With parasitic development, the malaria-infected RBC gradually loses its deformability, and in turn the corresponding trailing healthy RBC also deforms less due to the intercellular interaction. With increasing capillary number, both the healthy and malaria-infected RBCs are likely to undergo an axisymmetric motion. The minimum intercellular distance becomes small enough so that rouleaux is easily formed, i.e., the healthy and malaria-infected RBCs are difficultly disaggregated.« less

Exercise during Short-Term and Long-Term Continuous Exposure to Hypoxia Exacerbates Sleep-Related Periodic Breathing.

PubMed

Tellez, Helio Fernandez; Morrison, Shawnda A; Neyt, Xavier; Mairesse, Olivier; Piacentini, Maria Francesca; Macdonald-Nethercott, Eoin; Pangerc, Andrej; Dolenc-Groselj, Leja; Eiken, Ola; Pattyn, Nathalie; Mekjavic, Igor B; Meeusen, Romain

2016-04-01

Exposure to hypoxia elevates chemosensitivity, which can lead to periodic breathing. Exercise impacts gas exchange, altering chemosensitivity; however, interactions between sleep, exercise and chronic hypoxic exposure have not been examined. This study investigated whether exercise exacerbates sleep-related periodic breathing in hypoxia. Two experimental phases. Short-Term Phase: a laboratory controlled, group-design study in which 16 active, healthy men (age: 25 ± 3 y, height: 1.79 ± 0.06 m, mass: 74 ± 8 kg) were confined to a normobaric hypoxic environment (FIO2 = 0.139 ± 0.003, 4,000 m) for 10 days, after random assignment to a sedentary (control, CON) or cycle-exercise group (EX). Long-Term Phase: conducted at the Concordia Antarctic Research Station (3,800 m equivalent at the Equator) where 14 men (age: 36 ± 9 y, height: 1.77 ± 0.09 m, mass: 75 ± 10 kg) lived for 12-14 months, continuously confined. Participants were stratified post hoc based on self-reported physical activity levels. We quantified apnea-hypopnea index (AHI) and physical activity variables. Short-Term Phase: mean AHI scores were significantly elevated in the EX group compared to CON (Night1 = CON: 39 ± 51, EX: 91 ± 59; Night10 = CON: 32 ± 32, EX: 92 ± 48; P = 0.046). Long-Term Phase: AHI was correlated to mean exercise time (R(2) = 0.4857; P = 0.008) and the coefficient of variation in night oxyhemoglobin saturation (SpO2; R(2) = 0.3062; P = 0.049). Data indicate that exercise (physical activity) per se affects night SpO2 concentrations and AHI after a minimum of two bouts of moderate-intensity hypoxic exercise, while habitual physical activity in hypobaric hypoxic confinement affects breathing during sleep, up to 13+ months' duration. © 2016 Associated Professional Sleep Societies, LLC.

Exhaled isoprene for monitoring recovery from acute hypoxic stress.

PubMed

Harshman, Sean W; Geier, Brian A; Qualley, Anthony V; Drummond, Leslie A; Flory, Laura E; Fan, Maomian; Pitsch, Rhonda L; Grigsby, Claude C; Phillips, Jeffrey B; Martin, Jennifer A

2017-11-29

Hypoxia-like incidents in-flight have increased over the past decade causing severe safety concerns across the aviation community. As a result, the need to monitor flight crews in real-time for the onset of hypoxic conditions is paramount for continued aeronautical safety. Here, hypoxic events were simulated in the laboratory via a reduced oxygen-breathing device to determine the effect of recovery gas oxygen concentration (21% and 100%) on exhaled breath volatile organic compound composition. Data from samples collected both serially (throughout the exposure), prior to, and following exposures yielded 326 statistically significant features, 203 of which were unique. Of those, 72 features were tentatively identified while 51 were verified with authentic standards. A comparison of samples collected serially between recovery and hypoxia time points shows a statistically significant reduction in exhaled breath isoprene (2-methyl-1,3-butadiene, log 2 FC -0.399, p = 0.005, FDR = 0.034, q = 0.033), however no significant difference in isoprene abundance was observed when comparing recovery gases (21% or 100% O 2 , p = 0.152). Furthermore, examination of pre-/post-exposure 1 l bag breath samples illustrate an overall increase in exhaled isoprene abundance post-exposure (log 2 FC 0.393, p = 0.005, FDR = 0.094, q = 0.033) but again no significant difference between recovery gas (21% and 100%, p = 0.798) was observed. A statistically significant difference in trend was observed between isoprene abundance and recovery gases O 2 concentration when plotted against minimum oxygen saturation (p = 0.0419 100% O 2 , p = 0.7034 21% O 2 ). Collectively, these results suggest exhaled isoprene is dynamic in the laboratory ROBD setup and additional experimentation will be required to fully understand the dynamics of isoprene in response to acute hypoxic stress.

Testosterone Conversion Blockade Increases Breathing Stability in Healthy Men during NREM Sleep

PubMed Central

Chowdhuri, Susmita; Bascom, Amy; Mohan, David; Diamond, Michael P.; Badr, M. Safwan

2013-01-01

Study Objectives: Gender differences in the prevalence of sleep apnea/hypopnea syndrome may be mediated via male sex hormones. Our objective was to determine the exact pathway for a testosterone-mediated increased propensity for central sleep apnea via blockade of the 5α-reductase pathway of testosterone conversion by finasteride. Design: Randomization to oral finasteride vs. sham, single-center study. Setting: Sleep research laboratory. Participants: Fourteen healthy young males without sleep apnea Intervention: Hypocapnia was induced via brief nasal noninvasive positive pressure ventilation during stable NREM sleep. Cessation of mechanical ventilation resulted in hypocapnic central apnea or hypopnea. Measurements and Results: The apnea threshold (AT) was defined as the end-tidal CO2 (PETCO2) that demarcated the central apnea closest to the eupneic PETCO2. The CO2 reserve was defined as the difference in PETCO2 between eupnea and AT. The apneic threshold and CO2 reserve were measured at baseline and repeated after at a minimum of 1 month. Administration of finasteride resulted in decreased serum dihydrotestosterone. In the finasteride group, the eupneic ventilatory parameters were unchanged; however, the AT was decreased (38.9 ± 0.6 mm Hg vs.37.7 ± 0.9 mm Hg, P = 0.02) and the CO2 reserve was increased (-2.5 ± 0.3 mm Hg vs. -3.8 ± 0.5 mm Hg, P = 0.003) at follow-up, with a significantly lower hypocapnic ventilatory response, thus indicating increased breathing stability during sleep. No significant changes were noted in the sham group on follow-up study. Conclusions: Inhibition of testosterone action via the 5α-reductase pathway may be effective in alleviating breathing instability during sleep, presenting an opportunity for novel therapy for central sleep apnea in selected populations. Citation: Chowdhuri S; Bascom A; Mohan D; Diamond MP; Badr MS. Testosterone conversion blockade increases breathing stability in healthy men during NREM sleep. SLEEP 2013;36(12):1793-1798. PMID:24293753

Power and Efficiency Optimized in Traveling-Wave Tubes Over a Broad Frequency Bandwidth

NASA Technical Reports Server (NTRS)

Wilson, Jeffrey D.

2001-01-01

A traveling-wave tube (TWT) is an electron beam device that is used to amplify electromagnetic communication waves at radio and microwave frequencies. TWT's are critical components in deep space probes, communication satellites, and high-power radar systems. Power conversion efficiency is of paramount importance for TWT's employed in deep space probes and communication satellites. A previous effort was very successful in increasing efficiency and power at a single frequency (ref. 1). Such an algorithm is sufficient for narrow bandwidth designs, but for optimal designs in applications that require high radiofrequency power over a wide bandwidth, such as high-density communications or high-resolution radar, the variation of the circuit response with respect to frequency must be considered. This work at the NASA Glenn Research Center is the first to develop techniques for optimizing TWT efficiency and output power over a broad frequency bandwidth (ref. 2). The techniques are based on simulated annealing, which has the advantage over conventional optimization techniques in that it enables the best possible solution to be obtained (ref. 3). Two new broadband simulated annealing algorithms were developed that optimize (1) minimum saturated power efficiency over a frequency bandwidth and (2) simultaneous bandwidth and minimum power efficiency over the frequency band with constant input power. The algorithms were incorporated into the NASA coupled-cavity TWT computer model (ref. 4) and used to design optimal phase velocity tapers using the 59- to 64-GHz Hughes 961HA coupled-cavity TWT as a baseline model. In comparison to the baseline design, the computational results of the first broad-band design algorithm show an improvement of 73.9 percent in minimum saturated efficiency (see the top graph). The second broadband design algorithm (see the bottom graph) improves minimum radiofrequency efficiency with constant input power drive by a factor of 2.7 at the high band edge (64 GHz) and increases simultaneous bandwidth by 500 MHz.

Technical note: optimization for improved tube-loading efficiency in the dual-energy computed tomography coupled with balanced filter method.

PubMed

Saito, Masatoshi

2010-08-01

This article describes the spectral optimization of dual-energy computed tomography using balanced filters (bf-DECT) to reduce the tube loadings and dose by dedicating to the acquisition of electron density information, which is essential for treatment planning in radiotherapy. For the spectral optimization of bf-DECT, the author calculated the beam-hardening error and air kerma required to achieve a desired noise level in an electron density image of a 50-cm-diameter cylindrical water phantom. The calculation enables the selection of beam parameters such as tube voltage, balanced filter material, and its thickness. The optimal combination of tube voltages was 80 kV/140 kV in conjunction with Tb/Hf and Bi/Mo filter pairs; this combination agrees with that obtained in a previous study [M. Saito, "Spectral optimization for measuring electron density by the dual-energy computed tomography coupled with balanced filter method," Med. Phys. 36, 3631-3642 (2009)], although the thicknesses of the filters that yielded a minimum tube output were slightly different from those obtained in the previous study. The resultant tube loading of a low-energy scan of the present bf-DECT significantly decreased from 57.5 to 4.5 times that of a high-energy scan for conventional DECT. Furthermore, the air kerma of bf-DECT could be reduced to less than that of conventional DECT, while obtaining the same figure of merit for the measurement of electron density and effective atomic number. The tube-loading and dose efficiencies of bf-DECT were considerably improved by sacrificing the quality of the noise level in the images of effective atomic number.

Effect of milk on the deodorization of malodorous breath after garlic ingestion.

PubMed

Hansanugrum, Areerat; Barringer, Sheryl A

2010-08-01

The effect of milk and milk components on the deodorization of diallyl disulfide (DADS), allyl methyl disulfide (AMDS), allyl mercaptan (AM), allyl methyl sulfide (AMS), and methyl mercaptan (MM) in the headspace of garlic as well as in the mouth- and nose-space after garlic ingestion was investigated using selected ion flow tube-mass spectrometry (SIFT-MS). Fat-free and whole milk significantly reduced the head-, mouth-, and nose-space concentrations of all volatiles. Water was the major component in milk responsible for the deodorization of volatiles. Due to its higher fat content, whole milk was more effective than fat-free milk in the deodorization of the more hydrophobic volatiles diallyl disulfide and allyl methyl disulfide. Milk was more effective than water and 10% sodium caseinate in the deodorization of allyl methyl sulfide, a persistent garlic odor, in the mouth after garlic ingestion. Addition of milk to garlic before ingestion had a higher deodorizing effect on the volatiles in the mouth than drinking milk after consuming garlic. Practical Application: Ingesting beverages or foods with high water and/or fat content such as milk may help reduce the malodorous odor in breath after garlic ingestion and mask the garlic flavor during eating. To enhance the deodorizing effect, deodorant foods should be mixed with garlic before ingestion.

Lung Motion Model Validation Experiments, Free-Breathing Tissue Densitometry, and Ventilation Mapping using Fast Helical CT Imaging

NASA Astrophysics Data System (ADS)

Dou, Hsiang-Tai

The uncertainties due to respiratory motion present significant challenges to accurate characterization of cancerous tissues both in terms of imaging and treatment. Currently available clinical lung imaging techniques are subject to inferior image quality and incorrect motion estimation, with consequences that can systematically impact the downstream treatment delivery and outcome. The main objective of this thesis is the development of the techniques of fast helical computed tomography (CT) imaging and deformable image registration for the radiotherapy applications in accurate breathing motion modeling, lung tissue density modeling and ventilation imaging. Fast helical CT scanning was performed on 64-slice CT scanner using the shortest available gantry rotation time and largest pitch value such that scanning of the thorax region amounts to just two seconds, which is less than typical breathing cycle in humans. The scanning was conducted under free breathing condition. Any portion of the lung anatomy undergoing such scanning protocol would be irradiated for only a quarter second, effectively removing any motion induced image artifacts. The resulting CT data were pristine volumetric images that record the lung tissue position and density in a fraction of the breathing cycle. Following our developed protocol, multiple fast helical CT scans were acquired to sample the tissue positions in different breathing states. To measure the tissue displacement, deformable image registration was performed that registers the non-reference images to the reference one. In modeling breathing motion, external breathing surrogate signal was recorded synchronously with the CT image slices. This allowed for the tissue-specific displacement to be modeled as parametrization of the recorded breathing signal using the 5D lung motion model. To assess the accuracy of the motion model in describing tissue position change, the model was used to simulate the original high-pitch helical CT scan geometries, employed as ground truth data. Image similarity between the simulated and ground truth scans was evaluated. The model validation experiments were conducted in a patient cohort of seventeen patients to assess the model robustness and inter-patient variation. The model error averaged over multiple tracked positions from several breathing cycles was found to be on the order of one millimeter. In modeling the density change under free breathing condition, the determinant of Jacobian matrix from the registration-derived deformation vector field yielded volume change information of the lung tissues. Correlation of the Jacobian values to the corresponding voxel Housfield units (HU) reveals that the density variation for the majority of lung tissues can be very well described by mass conservation relationship. Different tissue types were identified and separately modeled. Large trials of validation experiments were performed. The averaged deviation between the modeled and the reference lung density was 30 HU, which was estimated to be the background CT noise level. In characterizing the lung ventilation function, a novel method was developed to determine the extent of lung tissue volume change. Information on volume change was derived from the deformable image registration of the fast helical CT images in terms of Jacobian values with respect to a reference image. Assuming the multiple volume change measurements are independently and identically distributed, statistical formulation was derived to model ventilation distribution of each lung voxels and empirical minimum and maximum probability distribution of the Jacobian values was computed. Ventilation characteristic was evaluated as the difference of the expectation value from these extremal distributions. The resulting ventilation map was compared with an independently obtained ventilation image derived directly from the lung intensities and good correlation was found using statistical test. In addition, dynamic ventilation characterization was investigated by estimating the voxel-specific ventilation distribution. Ventilation maps were generated at different percentile levels using the tissue volume expansion metrics.

Free-breathing high-pitch 80kVp dual-source computed tomography of the pediatric chest: Image quality, presence of motion artifacts and radiation dose.

PubMed

Bodelle, Boris; Fischbach, Constanze; Booz, Christian; Yel, Ibrahim; Frellesen, Claudia; Beeres, Martin; Vogl, Thomas J; Scholtz, Jan-Erik

2017-04-01

To investigate image quality, presence of motion artifacts and effects on radiation dose of 80kVp high-pitch dual-source CT (DSCT) in combination with an advanced modeled iterative reconstruction algorithm (ADMIRE) of the pediatric chest compared to single-source CT (SSCT). The study was approved by the institutional review board. Eighty-seven consecutive pediatric patients (mean age 9.1±4.9years) received either free-breathing high-pitch (pitch 3.2) chest 192-slice DSCT (group 1, n=31) or standard-pitch (pitch 1.2) 128-slice SSCT (group 2, n=56) with breathing-instructions by random assignment. Tube settings were similar in both groups with 80 kVp and 74 ref. mAs. Images were reconstructed using FBP for both groups. Additionally, ADMIRE was used in group 1. Effective thorax diameter, image noise, and signal-to-noise ratio (SNR) of the pectoralis major muscle and the thoracic aorta were calculated. Motion artifacts were measured as doubling boarders of the diaphragm and the heart. Images were rated by two blinded readers for overall image quality and presence of motion artifacts on 5-point-scales. Size specific dose estimates (SSDE, mGy) and effective dose (ED, mSv) were calculated. Age and effective thorax diameter showed no statistically significant differences in both groups. Image noise and SNR were comparable (p>0.64) for SSCT and DSCT with ADMIRE, while DSCT with FBP showed inferior results (p<0.01). Motion artifacts were reduced significantly (p=0.001) with DSCT. DSCT with ADMIRE showed the highest overall IQ (p<0.0001). Radiation dose was lower for DSCT compared to SSCT (median SSDE: 0.82mGy vs. 0.92mGy, p<0.02; median ED: 0.4 mSv vs. 0.48mSv, p=0.02). High-pitch 80kVp chest DSCT in combination with ADMIRE reduces motion artifacts and increases image quality while lowering radiation exposure in free-breathing pediatric patients without sedation. Copyright © 2017 Elsevier B.V. All rights reserved.

Influence of different interfaces on synchrony during pressure support ventilation in a pediatric setting: a bench study.

PubMed

Conti, Giorgio; Gregoretti, Cesare; Spinazzola, Giorgia; Festa, Olimpia; Ferrone, Giuliano; Cipriani, Flora; Rossi, Marco; Piastra, Marco; Costa, Roberta

2015-04-01

In adults and children, patient-ventilator synchrony is strongly dependent on both the ventilator settings and interface used in applying positive pressure to the airway. The aim of this bench study was to determine whether different interfaces and ventilator settings may influence patient-ventilator interaction in pediatric models of normal and mixed obstructive and restrictive respiratory conditions. A test lung, connected to a pediatric mannequin using different interfaces (endotracheal tube [ETT], face mask, and helmet), was ventilated in pressure support ventilation mode testing 2 ventilator settings (pressurization time [Timepress]50%/cycling-off flow threshold [Trexp]25%, Timepress80%/Trexp60%), randomly applied. The test lung was set to simulate one pediatric patient with a healthy respiratory system and another with a mixed obstructive and restricted respiratory condition, at different breathing frequencies (f) (30, 40, and 50 breaths/min). We measured inspiratory trigger delay, pressurization time, expiratory trigger delay, and time of synchrony. At each breathing frequency, the helmet showed the longest inspiratory trigger delay compared with the ETT and face mask. At f30, the ETT had a reduced Tpress. The helmet had the shortest Tpress in the simulated child with a mixed obstructive and restricted respiratory condition, at f40 during Timepress50%/Trexp25% and at f50 during Timepress80%/Trexp60%. In the simulated child with a normal respiratory condition, the ETT presented the shortest Tpress value at f50 during Timepress80%/Trexp60%. Concerning the expiratory trigger delay, the helmet showed the best interaction at f30, but the worst at f40 and at f50. The helmet showed the shortest time of synchrony during all ventilator settings. The choice of the interface can influence patient-ventilator synchrony in a pediatric model breathing at increased f, thus making it more difficult to set the ventilator, particularly during noninvasive ventilation. The helmet demonstrated the worst interaction, suggesting that the face mask should be considered as the first choice for delivering noninvasive ventilation in a pediatric model. Copyright © 2015 by Daedalus Enterprises.

Comparison of quantitative regional ventilation-weighted fourier decomposition MRI with dynamic fluorinated gas washout MRI and lung function testing in COPD patients.

PubMed

Kaireit, Till F; Gutberlet, Marcel; Voskrebenzev, Andreas; Freise, Julia; Welte, Tobias; Hohlfeld, Jens M; Wacker, Frank; Vogel-Claussen, Jens

2018-06-01

Ventilation-weighted Fourier decomposition-MRI (FD-MRI) has matured as a reliable technique for quantitative measures of regional lung ventilation in recent years, but has yet not been validated in COPD patients. To compare regional fractional lung ventilation obtained by ventilation-weighted FD-MRI with dynamic fluorinated gas washout MRI ( 19 F-MRI) and lung function test parameters. Prospective study. Twenty-seven patients with chronic obstructive pulmonary disease (COPD, median age 61 [54-67] years) were included. For FD-MRI and for 19 F-MRI a spoiled gradient echo sequence was used at 1.5T. FD-MRI coronal slices were acquired in free breathing. Dynamic 19 F-MRI was performed after inhalation of 25-30 L of a mixture of 79% fluorinated gas (C 3 F 8 ) and 21% oxygen via a closed face mask tubing using a dedicated coil tuned to 59.9 MHz. 19 F washout times in numbers of breaths ( 19 F-n breaths ) as well as fractional ventilation maps for both methods (FD-FV, 19 F-FV) were calculated. Slices were matched using a landmark driven algorithm, and only corresponding slices with an overlap of >90% were coregistered for evaluation. The obtained parameters were correlated with each other using Spearman's correlation coefficient (r). FD-FV strongly correlated with 19 F-n breaths on a global (r = -0.72, P < 0.0001) as well as on a lobar level and with lung function test parameters (FD-FV vs. FEV1, r = 0.76, P < 0.0001). There was a small systematic overestimation of FD-FV compared to 19 F-FV (mean difference -0.03 (95% confidence interval [CI]: -0.097; -0.045). Regional ventilation-weighted Fourier decomposition-MRI is a promising noninvasive, radiation-free tool for quantification of regional ventilation in COPD patients. 2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;47:1534-1541. © 2017 International Society for Magnetic Resonance in Medicine.

Humidity and Inspired Oxygen Concentration During High-Flow Nasal Cannula Therapy in Neonatal and Infant Lung Models.

PubMed

Chikata, Yusuke; Ohnishi, Saki; Nishimura, Masaji

2017-05-01

High-flow nasal cannula therapy (HFNC) for neonate/infants can deliver up to 10 L/min of heated and humidified gas, and F IO 2 can be adjusted to between 0.21 and 1.0. With adults, humidification and actual F IO 2 are known to vary according to inspiratory and HFNC gas flow, tidal volume (V T ), and ambient temperature. There have been few studies focused on humidification and F IO 2 in HFNC settings for neonates/infants, so we performed a bench study to investigate the influence of gas flow, ambient temperature, and respiratory parameters on humidification and actual F IO 2 in a neonate/infant simulation. HFNC gas flow was set at 3, 5, and 7 L/min, and F IO 2 was set at 0.3, 0.5, and 0.7. Spontaneous breathing was simulated using a 2-bellows-in-a-box model of a neonate lung. Tests were conducted with V T settings of 20, 30, and 40 mL and breathing frequencies of 20 and 30 breaths/min. Inspiratory time was 0.8 s with decelerating flow waveform. The HFNC tube was placed in an incubator, which was either set at 37°C or turned off. Absolute humidity (AH) and actual F IO 2 were measured for 1 min using a hygrometer and an oxygen analyzer, and data for the final 3 breaths were extracted. At all settings, when the incubator was turned on, AH was greater than when it was turned off ( P < .001). When the incubator was turned off, as gas flow increased, AH increased ( P < .001); however, V T did not affect AH ( P = .16). As gas flow increased, actual F IO 2 more closely corresponded to set F IO 2 . When gas flow was 3 L/min, measured F IO 2 decreased proportionally more at each F IO 2 setting increment ( P < .001). AH was affected by ambient temperature and HFNC gas flow. Actual F IO 2 depended on V T when gas flow was 3 L/min. Copyright © 2017 by Daedalus Enterprises.

From catastrophic acceleration to deceleration of liquid plugs in prewetted capillary tubes

NASA Astrophysics Data System (ADS)

Magniez, Juan; Baudoin, Michael; Zoueshtiagh, Farzam; Lemac/Lics Team

2016-11-01

Liquid/gas flows in capillaries are involved in a multitude of systems including flow in porous media, petroleum extraction, imbibition of paper or flows in pulmonary airways in pathological conditions. Liquid plugs, witch compose the biphasic flows, can have a dramatic impact on patients with pulmonary obstructive diseases, since they considerably alter the circulation of air in the airways and thus can lead to severe breathing difficulties. Here, the dynamics of liquid plugs in prewetted capillary tube is investigated experimentally and theoretically, with a particular emphasis on the role of the prewetting films and of the driving condition (constant flow rate, constant pressure). For both driving conditions, the plugs can either experience a continuous increase or decrease of their size. While this phenomenon is regular in the case of imposed flow rate, a constant pressure head can lead to a catastrophic acceleration of the plug and eventually its rupture or a dramatic increase of the plug size. A theoretical model is proposed to explain the transition between theses two regimes. These results give a new insight on the critical pressure required for airways obstruction and reopening. IEMN, International Laboratory LEMAC/LICS, UMR CNRS 8520, University of Lille.

[Virtual bronchoscopy in the child using multi-slice CT: initial clinical experiences].

PubMed

Kirchner, J; Laufer, U; Jendreck, M; Kickuth, R; Schilling, E M; Liermann, D

2000-01-01

Virtual bronchoscopy of the pediatric patient has been reported to be more difficult because of artifacts due to breathing or motion. We demonstrate the benefit of the accelerated examination based on multislice spiral CT (MSCT) in the pediatric patient which has not been reported so far. MSCT (tube voltage 120 kV, tube current 110 mA, 4 x 1 mm Slice thickness, 500 ms rotation time, Pitch 6) was performed on a CT scanner of the latest generation (Volume Zoom, Siemens Corp. Forchheim, Germany). In totally we examined 11 patients (median age 48 months, range 2-122 months) suspected of having tracheoesophageal fistula (n = 2), tracheobronchial narrowing (n = 8) due to intrinsic or extrinsic factors or injury of the bronchial system (n = 1). In all patients we obtained sufficient data for 3D reconstruction avoiding general anesthesia. 6/11 examinations were described to be without pathological finding. A definite diagnosis was obtained in 10 patients. Virtual bronchoscopy could avoid other invasive diagnostic examination in 8/11 patients (73%). Helical CT provides 3D-reconstruction and virtual bronchoscopy in the newborn as well as the infant. It avoids additional diagnostic bronchoscopy in a high percentage of all cases.

Sturge-Weber syndrome: ear, nose, and throat issues and neurologic status.

PubMed

Irving, Natasha D; Lim, Jae Hyung; Cohen, Bernard; Ferenc, Lisa M; Comi, Anne M

2010-10-01

The pathophysiology of Sturge-Weber syndrome is poorly understood, and ear, nose, and throat involvement is possible. These issues can result in frequent illnesses or airway obstruction, affecting patients' neurologic status. Patients with definite brain involvement who reported potential ear, nose, and throat issues on intake questionnaires underwent retrospective reviews of their medical records. We examined the relationships between these issues, secondary surgical interventions, and patients' neurologic status. The most common complaints involved the sinuses and frequent ear infections. Six patients underwent placement of ear tubes, leading to improvements in migraines and stroke-like episodes in one patient, and improved seizure control in four others. Obstructive sleep apnea was confirmed in three patients who underwent sleep studies. Tonsil or adenoid removal occurred in another three patients. Surgery resulted in marked improvements regarding excessive drooling, daytime sleepiness, and breathing problems. These findings suggest that ear, nose, and throat problems occur frequently in patients with Sturge-Weber Syndrome, and when repeated ear infections are associated with uncontrolled seizures, early placement of ear tubes may be beneficial. Furthermore, patients with facial tissue hypertrophy may be at risk for obstructive sleep apnea, and should be appropriately evaluated. Copyright © 2010 Elsevier Inc. All rights reserved.

Investigation at Mach Numbers 2.98 and 2.18 of Axially Symmetric Free-jet Diffusion with a Ram-jet Engine

NASA Technical Reports Server (NTRS)

Hunczak, Henry R

1952-01-01

An investigation was conducted to determine the effectiveness of a free-jet diffuser in reducing the over-all pressure ratios required to operate a free jet with a large air-breathing engine as a test vehicle. Efficient operation of the free jet was determined with and without the considerations required for producing suitable engine-inlet flow conditions. A minimum operating pressure ration of 5.5 was attained with a ratio of nozzle-exit to engine-inlet area of 1.85. Operation of the free jet with unstable engine-inlet flow (buzz) is also included.

Underage access to online alcohol marketing content: a YouTube case study.

PubMed

Barry, Adam E; Johnson, Emily; Rabre, Alexander; Darville, Gabrielle; Donovan, Kristin M; Efunbumi, Orisatalabi

2015-01-01

With the proliferation of the Internet and online social media use, alcohol advertisers are now marketing their products through social media sites such as YouTube, Facebook and Twitter. As a result, new recommendations have been made by the Federal Trade Commission concerning the self-regulation of digital marketing strategies, including content management on social and digital media sites. The current study sought to determine whether alcohol companies were implementing the self-imposed mandates that they have developed for online marketing. Specifically, we examined whether alcohol companies were implementing effective strategies that would prevent persons under the minimum legal drinking age in the USA from accessing their content on YouTube. We assessed 16 alcohol brands (beer and liquor) associated with the highest prevalence of past 30 day underage alcohol consumption in the USA. Fictitious YouTube user profiles were created and assigned the ages of 14, 17 and 19. These profiles then attempted to access and view the brewer-sponsored YouTube channels for each of the 16 selected brands. Every underage profile, regardless of age, was able to successfully subscribe to each of the 16 (100%) official YouTube channels. On average, two-thirds of the brands' channels were successfully viewed (66.67%). Alcohol industry provided online marketing content is predominantly accessible to underage adolescents. Thus, brewers are not following some of the self-developed and self-imposed mandates for online advertising by failing to implement effective age-restriction measures (i.e. age gates). © The Author 2014. Medical Council on Alcohol and Oxford University Press. All rights reserved.

Fundamental basis and implementation of shell and tube heat exchanger project design: condenser and evaporator study

NASA Astrophysics Data System (ADS)

Dalkilic, A. S.; Acikgoz, O.; Tapan, S.; Wongwises, S.

2016-12-01

A shell and tube heat exchanger is used as a condenser and an evaporator in this theoretical study. Parametric performance analyses for various actual refrigerants were performed using well-known correlations in open sources. Condensation and evaporation were occurred in the shell side while the water was flowing in the tube side of heat exchanger. Heat transfer rate from tube side was kept constant for condenser and evaporator design. Condensing temperatures were varied from 35 to 60 °C whereas evaporating temperatures were ranging from -15 to 10 °C for the refrigerants of R12, R22, R134a, R32, R507A, R404A, R502, R407C, R152A, R410A and R1234ZE. Variation of convective heat transfer coefficients of refrigerants, total heat transfer coefficients with Reynolds numbers and saturation temperatures were given as validation process considering not only fouling resistance and omission of it but also staggered (triangular) and line (square) arrangements. The minimum tube lengths and necessary pumping powers were calculated and given as case studies for the investigated refrigerants considering validation criteria. It was understood that refrigerant type, fouling resistance and arrangement type are one of the crucial issues regarding the determination of heat exchanger's size and energy consumption. Consequently, R32 and R152a were found to require the shortest tube length and lowest pumping power in the condenser, whereas R507 and R407C have the same advantages in the evaporator. Their heat transfer coefficients were also determined larger than others as expectedly.

Impact of respiratory-correlated CT sorting algorithms on the choice of margin definition for free-breathing lung radiotherapy treatments.

PubMed

Thengumpallil, Sheeba; Germond, Jean-François; Bourhis, Jean; Bochud, François; Moeckli, Raphaël

2016-06-01

To investigate the impact of Toshiba phase- and amplitude-sorting algorithms on the margin strategies for free-breathing lung radiotherapy treatments in the presence of breathing variations. 4D CT of a sphere inside a dynamic thorax phantom was acquired. The 4D CT was reconstructed according to the phase- and amplitude-sorting algorithms. The phantom was moved by reproducing amplitude, frequency, and a mix of amplitude and frequency variations. Artefact analysis was performed for Mid-Ventilation and ITV-based strategies on the images reconstructed by phase- and amplitude-sorting algorithms. The target volume deviation was assessed by comparing the target volume acquired during irregular motion to the volume acquired during regular motion. The amplitude-sorting algorithm shows reduced artefacts for only amplitude variations while the phase-sorting algorithm for only frequency variations. For amplitude and frequency variations, both algorithms perform similarly. Most of the artefacts are blurring and incomplete structures. We found larger artefacts and volume differences for the Mid-Ventilation with respect to the ITV strategy, resulting in a higher relative difference of the surface distortion value which ranges between maximum 14.6% and minimum 4.1%. The amplitude- is superior to the phase-sorting algorithm in the reduction of motion artefacts for amplitude variations while phase-sorting for frequency variations. A proper choice of 4D CT sorting algorithm is important in order to reduce motion artefacts, especially if Mid-Ventilation strategy is used. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Imaging of cardiac perfusion of free-breathing small animals using dynamic phase-correlated micro-CT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sawall, Stefan; Kuntz, Jan; Socher, Michaela

Purpose:Mouse models of cardiac diseases have proven to be a valuable tool in preclinical research. The high cardiac and respiratory rates of free breathing mice prohibit conventional in vivo cardiac perfusion studies using computed tomography even if gating methods are applied. This makes a sacrification of the animals unavoidable and only allows for the application of ex vivo methods. Methods: To overcome this issue the authors propose a low dose scan protocol and an associated reconstruction algorithm that allows for in vivo imaging of cardiac perfusion and associated processes that are retrospectively synchronized to the respiratory and cardiac motion ofmore » the animal. The scan protocol consists of repetitive injections of contrast media within several consecutive scans while the ECG, respiratory motion, and timestamp of contrast injection are recorded and synchronized to the acquired projections. The iterative reconstruction algorithm employs a six-dimensional edge-preserving filter to provide low-noise, motion artifact-free images of the animal examined using the authors' low dose scan protocol. Results: The reconstructions obtained show that the complete temporal bolus evolution can be visualized and quantified in any desired combination of cardiac and respiratory phase including reperfusion phases. The proposed reconstruction method thereby keeps the administered radiation dose at a minimum and thus reduces metabolic inference to the animal allowing for longitudinal studies. Conclusions: The authors' low dose scan protocol and phase-correlated dynamic reconstruction algorithm allow for an easy and effective way to visualize phase-correlated perfusion processes in routine laboratory studies using free-breathing mice.« less

Effect of combined psycho-physiological stretching and breathing therapy on sexual satisfaction

PubMed Central

2013-01-01

Background During the last few decades, marital tensions and stresses have influenced various dimensions of life. The objective of the current study was to examine the effects of combined psycho-physiological therapy (stretching therapy combined with breathing exercise) on sexual satisfaction among heterosexual men. Methods For this research, we used “convenience sampling” to select 80 males, who were then split equally into two groups, the intervention group and the control group, both groups containing men who had voiced a desire to be in the experimental group. For collection of data, we used an identical quasi-experimental design called the “nonequivalent control group.” Therapy sessions, each lasting 90 to 120 min, were carried out on the same 3 days of the week (Sunday, Tuesday, and Thursday) for a total of 20 sessions. The volunteers were selected from heterosexual men with stable relationships, who had been married a minimum of 6 months and were ages 20 to 55 years of age. Pre-tests, post-tests, and follow-up tests were conducted in a clinic at the Hospital Universiti Sains Malaysia (HUSM [1] ). For assessment, we used the sexual satisfaction subscale of the ENRICH [2] questionnaire. Results The intervention group had better post-test scores than the control group. Also, follow-up test scores for the intervention group were marginally better than those for the control group, but the difference did not reach statistical significance. Conclusions Combined psycho-physiological therapy including stretching and breathing exercise leads to improved sexual satisfaction. PMID:23522405

30 CFR 7.27 - Test for flame resistance of brattice cloth.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Test for flame resistance of brattice cloth. 7... Ventilation Tubing § 7.27 Test for flame resistance of brattice cloth. (a) Test procedures. (1) Prepare 6... for a minimum of 24 hours at a temperature of 70 ±10 °F (21 ±5.5 °C) and a relative humidity of 55 ±10...

30 CFR 7.27 - Test for flame resistance of brattice cloth.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Test for flame resistance of brattice cloth. 7... Ventilation Tubing § 7.27 Test for flame resistance of brattice cloth. (a) Test procedures. (1) Prepare 6... for a minimum of 24 hours at a temperature of 70 ±10 °F (21 ±5.5 °C) and a relative humidity of 55 ±10...

30 CFR 7.27 - Test for flame resistance of brattice cloth.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Test for flame resistance of brattice cloth. 7... Ventilation Tubing § 7.27 Test for flame resistance of brattice cloth. (a) Test procedures. (1) Prepare 6... for a minimum of 24 hours at a temperature of 70 ±10 °F (21 ±5.5 °C) and a relative humidity of 55 ±10...

30 CFR 7.27 - Test for flame resistance of brattice cloth.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Test for flame resistance of brattice cloth. 7... Ventilation Tubing § 7.27 Test for flame resistance of brattice cloth. (a) Test procedures. (1) Prepare 6... for a minimum of 24 hours at a temperature of 70 ±10 °F (21 ±5.5 °C) and a relative humidity of 55 ±10...

30 CFR 7.27 - Test for flame resistance of brattice cloth.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Test for flame resistance of brattice cloth. 7... Ventilation Tubing § 7.27 Test for flame resistance of brattice cloth. (a) Test procedures. (1) Prepare 6... for a minimum of 24 hours at a temperature of 70 ±10 °F (21 ±5.5 °C) and a relative humidity of 55 ±10...

A novel reverse-osmosis wash water recycle system for manned space stations

NASA Technical Reports Server (NTRS)

Ray, R. J.; Babcock, W. C.; Barss, R. P.; Andrews, T. A.; Lachapelle, E. D.

1984-01-01

The preliminary development of a wash water recycle system utilizing an inside-skinned hollow-fiber membrane is described. This module configuration is based on tube-side feed and is highly resistant to fouling with a minimum of pretreatment. During an ongoing research program for NASA, these modules were operated on actual wash waters with no significant fouling for a period of 40 days. Due to the tube-side-feed flow in these hollow-fiber membranes, the fibers themselves become the pressure vessels, allowing the development of extremely lightweight membrane modules. During the NASA research program, a pre-prototype membrane module capable of processing 6 gallons per day of wash water at 97 percent recovery was developed that can be dry-stored and that weighs 120 g.

Measurement of sound velocity made easy using harmonic resonant frequencies with everyday mobile technology

NASA Astrophysics Data System (ADS)

Hirth, Michael; Kuhn, Jochen; Müller, Andreas

2015-02-01

Recent articles about smartphone experiments have described their applications as experimental tools in different physical contexts.1-4 They have established that smartphones facilitate experimental setups, thanks to the small size and diverse functions of mobile devices, in comparison to setups with computer-based measurements. In the experiment described in this article, the experimental setup is reduced to a minimum. The objective of the experiment is to determine the speed of sound with a high degree of accuracy using everyday tools. An article published recently proposes a time-of-flight method where sound or acoustic pulses are reflected at the ends of an open tube.5 In contrast, the following experiment idea is based on the harmonic resonant frequencies of such a tube, simultaneously triggered by a noise signal.

Sink fast and swim harder! Round-trip cost-of-transport for buoyant divers.

PubMed

Miller, Patrick J O; Biuw, Martin; Watanabe, Yuuki Y; Thompson, Dave; Fedak, Mike A

2012-10-15

Efficient locomotion between prey resources at depth and oxygen at the surface is crucial for breath-hold divers to maximize time spent in the foraging layer, and thereby net energy intake rates. The body density of divers, which changes with body condition, determines the apparent weight (buoyancy) of divers, which may affect round-trip cost-of-transport (COT) between the surface and depth. We evaluated alternative predictions from external-work and actuator-disc theory of how non-neutral buoyancy affects round-trip COT to depth, and the minimum COT speed for steady-state vertical transit. Not surprisingly, the models predict that one-way COT decreases (increases) when buoyancy aids (hinders) one-way transit. At extreme deviations from neutral buoyancy, gliding at terminal velocity is the minimum COT strategy in the direction aided by buoyancy. In the transit direction hindered by buoyancy, the external-work model predicted that minimum COT speeds would not change at greater deviations from neutral buoyancy, but minimum COT speeds were predicted to increase under the actuator disc model. As previously documented for grey seals, we found that vertical transit rates of 36 elephant seals increased in both directions as body density deviated from neutral buoyancy, indicating that actuator disc theory may more closely predict the power requirements of divers affected by gravity than an external work model. For both models, minor deviations from neutral buoyancy did not affect minimum COT speed or round-trip COT itself. However, at body-density extremes, both models predict that savings in the aided direction do not fully offset the increased COT imposed by the greater thrusting required in the hindered direction.

Multiwalled Carbon Nanotube/nanofiber Arrays as Conductive and Dry Adhesive Interface Materials

NASA Technical Reports Server (NTRS)

Tong, Tao; Zhao, Yang; Delzeit, Lance; Majumdar, Arun; Kashani, Ali

2004-01-01

We demonstrate the possibility of making conductive and dry adhesive interfaces between multiwalled carbon nanotube (MWNT) and nanofiber (MWNF) arrays grown by chemical vapor deposition with transition-metal as catalyst on highly Boron doped silicon substrates. The maximum observed adhesion force between MWNT and MWNF surfaces is 3.5 mN for an apparent contact area of 2 mm by 4 mm. The minimum contact resistance measured at the same time is approx.20 Omega. Contact resistances of MWNT-MWNT and MWNT-gold interfaces were also measured as pressure forces around several mN were applied at the interface. The resulting minimum contact resistances are on the same order but with considerable variation from sample to sample. For MWNT-MWNT contacts, a minimum contact resistance of approx.1 Omega is observed for a contact area of 2 mm by 1 mm. The relatively high contact resistances, considering the area density of the nanotubes, might be explained by the high cross-tube resistances at the contact interfaces.

Residual antibacterial activity of chlorhexidine and MTAD in human root dentin in vitro.

PubMed

Mohammadi, Zahed; Shahriari, Shahriar

2008-03-01

The purpose of this in vitro study was to compare the antimicrobial substantivity of BioPure MTAD, 2% chlorhexidine (CHX) and 2.6% sodium hypochlorite (NaOCl) in human root dentin. One hundred and ten dentin tubes prepared from human maxillary incisors were infected in vitro for 14 days with Enterococcus faecalis. The specimens were divided into five groups as follows: CHX; BioPure MTAD; NaOCl; infected dentin tubes (positive control); and sterile dentin tubes (negative control). Dentin chips were collected with round burs into Brain Heart Infusion (BHI) broth. After culturing, the number of colony-forming units (CFU) was counted. In all experimental groups, CFU was minimum after treatment (day 0), and the results obtained were significantly different from each other at any time period (P < 0.05). After treatment, the NaOCI group and BioPure MTAD group showed the lowest and highest number of CFU, respectively. In each group, the number of CFUs increased significantly by time-lapse (P < 0.05). In conclusion, the substantivity of BioPure MTAD was significantly greater than CHX and NaOCl.

A simple customized surgical guide for orthodontic miniplates with tube.

PubMed

Paek, Janghyun; Su, Ming-Jeaun; Kwon, Soon-Yong; Kim, Seong-Hun; Chung, Kyu-Rhim; Nelson, Gerald

2012-09-01

This article reports the use of a customized surgical guide for simple and precise C-tube plate placement with minimized incision. Patients who were planning to have orthodontic miniplate treatment because of narrow interradicular space were recruited for this study. A combined silicone and stainless steel wire surgical guide for the C-tube was fabricated on the cast model. The taller wire of the positioning guide is used to accurately start the incision. The incision guide-wire position is verified by placing the miniplate on the coronal horizontal wire to confirm that the incision will coordinate with the screw holes. Because the miniplate is firmly held in place, there is no risk of the miniplate anchoring screws (diameter, 1.5 mm; length, 4 mm) sliding on the bone surface during placement with a manual hand driver. The surgical guide was placed on the clinical site, and it allowed precise placement of the miniplate with minimum incision and preventing from slippage or path-of-insertion angulation errors that might interfere with accurate placement. Customized surgical guide enables precise planning for miniplate positions in anatomically complex sites.

Co-pyrolysis behaviors of saw dust and Shenfu coal in drop tube furnace and fixed bed reactor.

PubMed

Li, Shuaidan; Chen, Xueli; Wang, Li; Liu, Aibin; Yu, Guangsuo

2013-11-01

Co-pyrolysis behaviors of saw dust (SD) and Shenfu bituminous coal (SF) were studied in a drop tube furnace and a fixed bed reactor at different temperatures respectively. Six different biomass/coal ratios (B:C) were used. Compared the results with the calculated value obtained by the additional behavior, CO volume yields were lower while H2, CH4, CO2, volume yields were higher. Blend char yields had a good agreement with the calculated values, and their structures remained similar with SD and SF char's. Synergy effect occurred in gaseous phase, which was mainly caused by the secondary reactions. Compared the blend char yields in the drop tube furnace with those in the fixed bed reactor, the results showed the contacting way of biomass and coal particles had little influence on char yield in co-pyrolysis process. The reactivity index of blend char achieved the minimum at B:C=40:60 and the maximum at B:C=80:20. Copyright © 2013 Elsevier Ltd. All rights reserved.

Low vibration cooling using a pulse tube cooler and cryostat for the GRAVITY beam combiner instrument at the VLTI

NASA Astrophysics Data System (ADS)

Haug, M.; Haussmann, F.; Kellner, S.; Kern, L.; Eisenhauer, F.; Lizon, J.-L.; Dietrich, M.; Thummes, G.

2014-07-01

GRAVITY is a second generation VLTI instrument for high-precision narrow-angle astrometry and phase-referenced interferometric imaging in the astronomical K-band. The cryostat of the beam combiner instrument provides the required temperatures for the various subunits ranging from 40K to 290K with a milli-Kelvin temperature stability for some selected units. The bath cryostat is cooled with liquid nitrogen and makes use of the exhaust gas to cool the main optical bench to an intermediate temperature of 240K. The fringe tracking detector will be cooled separately by a single-stage pulse tube cooler to a temperature of 40K. The pulse tube cooler is optimized for minimum vibrations. In particular its warm side is connected to the 80K reservoir of the LN2 cryostat to minimize the required input power. All temperature levels are actively stabilized by electric heaters. The cold bench is supported separately from the vacuum vessel and the liquid nitrogen reservoir to minimize the transfer of acoustic noise onto the instrument.

Memristive Responses of Jammed Granular Copper Array Sensors to Mechanical Stress

DTIC Science & Technology

2014-03-27

called Industrial Tectonics Inc. (itiball.com) with the statement of 99.95% minimum copper; stating the residual is most likely silver [12]. Their...atmosphere hot plate and quartz tube furnace with controlled atmosphere were used to oxidize the spheres at various temperatures, the hot plate ...combination spheres, as was seen by Branly. Using a nitric acid etch and 15 minute (min.) hot plate oxidized sphere array consisting of four spheres

Novel imaging detailing the origins of a pneumothorax.

PubMed

Nakanishi, Kozo; Goto, Hidenori; Ito, Tomokazu; Nagata, Yasuhito; Hayashi, Shinichi; Ishihara, Toshihiro

2018-01-01

This is a prospective clinical study aimed at introducing a method to visualise the location of an air leak and to identify the bulla responsible on three-dimensional (3-D) cine CT. In 10 patients with spontaneous pneumothorax, dynamic 320-detector row CT was performed with injection of 0.9% saline into the affected pleural cavity via a preplaced chest tube. In eight cases, 3-D cine CT thoracography revealed the location of the air leak and the bulla responsible (7 cases: air stream sign; 1 case: repeated collapse and expansion of a bulla with the patient's breathing). Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Weld joint concepts for on-orbit repair of Space Station Freedom fluid system tube assemblies

NASA Technical Reports Server (NTRS)

Jolly, Steven D.

1993-01-01

Because Space Station Freedom (SSF) is an independent satellite, not depending upon another spacecraft for power, attitude control, or thermal regulation, it has a variety of tubular, fluid-carrying assemblies on-board. The systems of interest in this analysis provide breathing air (oxygen and nitrogen), a working fluid (two-phase anhydrous ammonia) for thermal control, and a monopropellant (hydrazine) for station reboost. The tube assemblies run both internally and externally with respect to the habitats. They are found in up to 50 ft. continuous lengths constructed of mostly AISI 316L stainless steel tubing, but also including some Inconel 625 nickel-iron and Monel 400 nickel-copper alloy tubing. The outer diameters (OD) of the tubes range from 0.25-1.25 inches, and the wall thickness between 0.028-.095 inches. The system operational pressures range from 377 psi (for the thermal control system) to 3400 psi (for the high pressure oxygen and nitrogen supply lines in the ECLSS). SSF is designed for a fifteen to thirty year mission. It is likely that the tubular assemblies (TA's) will sustain damage or fail during this lifetime such that they require repair or replacement. The nature of the damage will be combinations of punctures, chips, scratches, and creases and may be cosmetic or actually leaking. The causes of these hypothetical problems are postulated to be: (1) faulty or fatigued fluid joints--both QD's and butt-welds; (2) micro-meteoroid impacts; (3) collison with another man-made object; and (4) over-pressure strain or burst (system origin). While the current NASA baseline may be to temporarily patch the lines by clamping metal c-sections over the defect, and then perform high pressure injection of a sealing compound, it is clear that permanent repair of the line(s) is necessary. This permanent repair could be to replace the entire TA in the segment, or perhaps the segment itself, both alternatives being extremely expensive and risky. The former would likely require extensive EVA to release TA clamps and pose great risk to other engineering subsystems, and the latter would require major de-servicing of the Station.

A simple method for accurate endotracheal placement of an intubation tube in Guinea pigs to assess lung injury following chemical exposure.

PubMed

Nambiar, M P; Gordon, R K; Moran, T S; Richards, S M; Sciuto, A M

2007-01-01

ABSTRACT Guinea pigs are considered as the animal model of choice for toxicology and medical countermeasure studies against chemical warfare agents (CWAs) and toxic organophosphate pesticides because of the low levels of carboxylesterase compared to rats and mice. However, it is difficult to intubate guinea pigs without damaging the larynx to perform CWA inhalation experiments. We describe an easy technique of intubation of guinea pigs for accurate endotracheal placement of the intubation tube. The technique involves a speculum made by cutting the medium-size ear speculum in the midline leaving behind the intact circular connector to the otoscope. Guinea pigs were anesthetized with Telazol/meditomidine, the tongue was pulled using blunt forceps, and an otoscope attached with the specially prepared speculum was inserted gently. Insertion of the speculum raises the epiglottis and restrains the movements of vocal cord, which allows smooth insertion of the metal stylet-reinforced intubation tube. Accurate endotracheal placement of the intubation tube was achieved by measuring the length from the tracheal bifurcation to vocal cord and vocal cord to the upper front teeth. The average length of the trachea in guinea pigs (275 +/- 25 g) was 5.5 +/- 0.2 cm and the distance from the vocal cord to the front teeth was typically 3 cm. Coinciding an intubation tube marked at 6 cm with the upper front teeth accurately places the intubation tube 2.5 cm above the tracheal bifurcation. This simple method of intubation does not disturb the natural flora of the mouth and causes minimum laryngeal damage. It is rapid and reliable, and will be very valuable in inhalation exposure to chemical/biological warfare agents or toxic chemicals to assess respiratory toxicity and develop medical countermeasures.

The Effects of Bicycle Frame Geometry on Muscle Activation and Power During a Wingate Anaerobic Test

PubMed Central

Ricard, Mark D.; Hills-Meyer, Patrick; Miller, Michael G.; Michael, Timothy J.

2006-01-01

The purpose of this study was to compare the effects of bicycle seat tube angles (STA) of (72° and 82°) on power production and EMG of the vastus laeralis (VL), vastus medialis (VM), semimembranous (SM), biceps femoris (BF) during a Wingate test (WAT). Twelve experienced cyclists performed a WAT at each STA. Repeated measures ANOVA was used to identify differences in muscular activation by STA. EMG variables were normalized to isometric maximum voluntary contraction (MVC). Paired t-tests were used to test the effects of STA on: peak power, average power, minimum power and percent power drop. Results indicated BF activation was significantly lower at STA 82° (482.9 ± 166.6 %MVC·s) compared to STA 72° (712.6 ± 265.6 %MVC·s). There were no differences in the power variables between STAs. The primary finding was that increasing the STA from 72° to 82° enabled triathletes’ to maintain power production, while significantly reducing the muscular activation of the biceps femoris muscle. Key Points Road cyclists claim that bicycle seat tube angles between 72° and 76° are most effective for optimal performance in racing. Triathletes typically use seat tube angles greater than 76°. It is thought that a seat tube angle greater than 76° facilitates a smoother bike to run transition in the triathlon. Increasing the seat tube angle from 72 to 82 enabled triathletes’ to maintain power production, while significantly reducing the muscular activation of the biceps femoris muscle. Reduced hamstring muscular activation in the triathlon frame (82 seat tube angle) may serve to reduce hamstring tightness following the bike phase of the triathlon, allowing the runner to use a longer stride length. PMID:24198678

Analysis of Fuel Vaporization, Fuel-Air Mixing, and Combustion in Integrated Mixer-Flame Holders

NASA Technical Reports Server (NTRS)

Deur, J. M.; Cline, M. C.

2004-01-01

Requirements to limit pollutant emissions from the gas turbine engines for the future High-Speed Civil Transport (HSCT) have led to consideration of various low-emission combustor concepts. One such concept is the Integrated Mixer-Flame Holder (IMFH). This report describes a series of IMFH analyses performed with KIVA-II, a multi-dimensional CFD code for problems involving sprays, turbulence, and combustion. To meet the needs of this study, KIVA-II's boundary condition and chemistry treatments are modified. The study itself examines the relationships between fuel vaporization, fuel-air mixing, and combustion. Parameters being considered include: mixer tube diameter, mixer tube length, mixer tube geometry (converging-diverging versus straight walls), air inlet velocity, air inlet swirl angle, secondary air injection (dilution holes), fuel injection velocity, fuel injection angle, number of fuel injection ports, fuel spray cone angle, and fuel droplet size. Cases are run with and without combustion to examine the variations in fuel-air mixing and potential for flashback due to the above parameters. The degree of fuel-air mixing is judged by comparing average, minimum, and maximum fuel/air ratios at the exit of the mixer tube, while flame stability is monitored by following the location of the flame front as the solution progresses from ignition to steady state. Results indicate that fuel-air mixing can be enhanced by a variety of means, the best being a combination of air inlet swirl and a converging-diverging mixer tube geometry. With the IMFH configuration utilized in the present study, flashback becomes more common as the mixer tube diameter is increased and is instigated by disturbances associated with the dilution hole flow.

Surgical fires in laser laryngeal surgery: are we safe enough?

PubMed

Roy, Soham; Smith, Lee P

2015-01-01

Laser surgery of the larynx and airway remains high risk for the formation of operating room fire. Traditional methods of fire prevention have included use of "laser safe" tubes, inflation of a protective cuff with saline, and wet pledgets to protect the endotracheal tube from laser strikes. We tested a mechanical model of laser laryngeal surgery to evaluate the fire risk. Mechanical model. Laboratory. An intubation mannequin was positioned for suspension microlaryngoscopy. A Laser-Shield II cuffed endotracheal tube was placed through the larynx and the cuff inflated using saline. Wet pledgets covered the inflated cuff. A CO2 laser created an inadvertent cuff strike at varying oxygen concentrations. Risk reduction measures were implemented to discern any notable change in the outcome after fire. At 100% FiO2 an immediate fire with sustained flame was created and at 40% FiO2 a near immediate sustained flame was created. At 29% FiO2, a small nonsustained flame was noted. At room air, no fire was created. There was no discernible difference in the severity of laryngeal damage after the fire occurred whether the tube was immediately pulled from the mannequin or if saline was poured down the airway as a first response. While "laser safe" tubes provide a layer of protection against fires, they are not fire proof. Inadvertent cuff perforation may result in fire formation in low-level oxygen enriched environments. Placement of wet pledgets do not provide absolute protection. Endotracheal tube (ETT) cuffs should be placed distally well away from an inadvertent laser strike while maintaining the minimum supplemental oxygen necessary. © American Academy of Otolaryngology—Head and Neck Surgery Foundation 2014.

Low-Current, Xenon Orificed Hollow Cathode Performance for In-Space Applications

NASA Technical Reports Server (NTRS)

Domonkos, Matthew T.; Patterson, Michael J.; Gallimore, Alec D.

2002-01-01

An experimental investigation of the operating characteristics of 3.2-mm diameter orificed hollow cathodes was conducted to examine low current and low flow rate operation. Cathode power was minimized with an orifice aspect ratio of approximately one and the use of an enclosed keeper. Cathode flow rate requirements were proportional to orifice diameter and the inverse of the orifice length. The minimum power consumption in diode mode was 10-W, and the minimum mass flow rate required for spot-mode emission was approximately 0.08-mg/s. Cathode temperature profiles were obtained using an imaging radiometer and conduction was found to be the dominant heat transfer mechanism from the cathode tube. Orifice plate temperatures were found to be weakly dependent upon the flow rate and strongly dependent upon the current.

Flow and pressure regulation in the cardiovascular system. [engineering systems model

NASA Technical Reports Server (NTRS)

Iberall, A.

1974-01-01

Principles and descriptive fragments which may contribute to a model of the regulating chains in the cardiovascular system are presented. Attention is given to the strain sensitivity of blood vessels, the law of the autonomy of the heart beat oscillator, the law of the encapsulation of body fluids, the law of the conservation of protein, the law of minimum 'arterial' pressure, the design of the 'mammalian' kidney, questions of homeokinetic organization, and the development of self-regulatory chains. Details concerning the development program for the heart muscle are considered along with the speed of response of the breathing rate and the significance of the pulmonary vascular pressure-flow characteristics.

Equilibrium intermediate-state patterns in a type-I superconducting slab in an arbitrarily oriented applied magnetic field

DOE PAGES

Clem, John; Prozorov, Ruslan; Wijngaarden, Rinke J.

2013-09-04

The equilibrium topology of superconducting and normal domains in flat type-I superconductors is investigated. Important improvements with respect to previous work are that (1) the energy of the external magnetic field, as deformed by the presence of superconducting domains, is calculated in the same way for three different topologies and (2) calculations are made for arbitrary orientation of the applied field. A phase diagram is presented for the minimum-energy topology as a function of applied field magnitude and angle. For small (large) applied fields, normal (superconducting) tubes are found, while for intermediate fields, parallel domains have a lower energy. Themore » range of field magnitudes for which the superconducting-tubes structure is favored shrinks when the field is more in-plane oriented.« less

Application of quadratic optimization to supersonic inlet control.

NASA Technical Reports Server (NTRS)

Lehtinen, B.; Zeller, J. R.

1972-01-01

This paper describes the application of linear stochastic optimal control theory to the design of the control system for the air intake, the inlet, of a supersonic air-breathing propulsion system. The controls must maintain a stable inlet shock position in the presence of random airflow disturbances and prevent inlet unstart. Two different linear time invariant controllers are developed. One is designed to minimize a nonquadratic index, the expected frequency of inlet unstart, and the other is designed to minimize the mean square value of inlet shock motion. The quadratic equivalence principle is used to obtain a linear controller that minimizes the nonquadratic index. The two controllers are compared on the basis of unstart prevention, control effort requirements, and frequency response. It is concluded that while controls designed to minimize unstarts are desirable in that the index minimized is physically meaningful, computation time required is longer than for the minimum mean square shock position approach. The simpler minimum mean square shock position solution produced expected unstart frequency values which were not significantly larger than those of the nonquadratic solution.

Lack of Feeding Progression in a Preterm Infant: A Case Study

PubMed Central

White-Traut, Rosemary; Shapiro, Nicole; Healy-Baker, Elissa; Menchavez, Lina; Rankin, Kristin; Medoff-Cooper, Barbara

2012-01-01

Purpose To present the case of a premature infant who displayed immature feeding progression due to nasal occlusion. Subjects Two male preterm infants 33 weeks gestational age at birth from a larger randomized trial. Design Comparative case study. Methods Using a prospective design, feeding assessments were conducted weekly from initiation of oral feeding until hospital discharge. Sucking organization was measured using the Medoff-Cooper Nutritive Sucking Apparatus (M-CNSA) which measured negative sucking pressure generated during oral feedings. Oral and nasogastric (NG) intake and vital signs were recorded. Results At 35 weeks, Infant A demonstrated an immature feeding pattern with NG feedings prevailing over oral feedings. When attempting to feed orally, Infant A exhibited labored breathing and an erratic sucking pattern. During the third weekly feeding evaluation, nasal occlusion was discovered, the NG tube was discontinued, and neosynephrene and humidified air were administered. Following treatment, Infant A’s sucking pattern normalized and the infant maintained complete oral feeding. Infant B demonstrated normal feeding progression. Conclusion Nasal occlusion prevented Infant A from achieving successful oral feeding. The M-CNSA has the ability to help clinicians detect inconsistencies in the breath-suck-swallow feeding patterns of infants and objectively measures patterns of nutritive sucking. The M-CNSA has the potential to influence clinical decision making and identify the need for intervention. PMID:23722488

Needle thoracostomy for tension pneumothorax: the Israeli Defense Forces experience.

PubMed

Chen, Jacob; Nadler, Roy; Schwartz, Dagan; Tien, Homer; Cap, Andrew P; Glassberg, Elon

2015-06-01

Point of injury needle thoracostomy (NT) for tension pneumothorax is potentially lifesaving. Recent data raised concerns regarding the efficacy of conventional NT devices. Owing to these considerations, the Israeli Defense Forces Medical Corps (IDF-MC) recently introduced a longer, wider, more durable catheter for the performance of rapid chest decompression. The present series represents the IDF-MC experience with chest decompression by NT. We reviewed the IDF trauma registry from January 1997 to October 2012 to identify all cases in which NT was attempted. During the study period a total of 111 patients underwent chest decompression by NT. Most casualties (54%) were wounded as a result of gunshot wounds (GSW); motor vehicle accidents (MVAs) were the second leading cause (16%). Most (79%) NTs were performed at the point of injury, while the rest were performed during evacuation by ambulance or helicopter (13% and 4%, respectively). Decreased breath sounds on the affected side were one of the most frequent clinical indications for NT, recorded in 28% of cases. Decreased breath sounds were more common in surviving than in nonsurviving patients. (37% v. 19%, p < 0.001). A chest tube was installed on the field in 35 patients (32%), all after NT. Standard NT has a high failure rate on the battlefield. Alternative measures for chest decompression, such as the Vygon catheter, appear to be a feasible alternative to conventional NT.

Needle thoracostomy for tension pneumothorax: the Israeli Defense Forces experience

PubMed Central

Chen, LTC Jacob; Nadler, Capt Roy; Schwartz, Maj Dagan; Tien, Col Homer; Cap, LTC Andrew P.; Glassberg, Col Elon

2015-01-01

Background Point of injury needle thoracostomy (NT) for tension pneumothorax is potentially lifesaving. Recent data raised concerns regarding the efficacy of conventional NT devices. Owing to these considerations, the Israeli Defense Forces Medical Corps (IDF-MC) recently introduced a longer, wider, more durable catheter for the performance of rapid chest decompression. The present series represents the IDF-MC experience with chest decompression by NT. Methods We reviewed the IDF trauma registry from January 1997 to October 2012 to identify all cases in which NT was attempted. Results During the study period a total of 111 patients underwent chest decompression by NT. Most casualties (54%) were wounded as a result of gunshot wounds (GSW); motor vehicle accidents (MVAs) were the second leading cause (16%). Most (79%) NTs were performed at the point of injury, while the rest were performed during evacuation by ambulance or helicopter (13% and 4%, respectively). Decreased breath sounds on the affected side were one of the most frequent clinical indications for NT, recorded in 28% of cases. Decreased breath sounds were more common in surviving than in nonsurviving patients. (37% v. 19%, p < 0.001). A chest tube was installed on the field in 35 patients (32%), all after NT. Conclusion Standard NT has a high failure rate on the battlefield. Alternative measures for chest decompression, such as the Vygon catheter, appear to be a feasible alternative to conventional NT. PMID:26100771

Kinking and Torsion Can Significantly Improve the Efficiency of Valveless Pumping in Periodically Compressed Tubular Conduits. Implications for Understanding of the Form-Function Relationship of Embryonic Heart Tubes.

PubMed

Hiermeier, Florian; Männer, Jörg

2017-11-19

Valveless pumping phenomena (peristalsis, Liebau-effect) can generate unidirectional fluid flow in periodically compressed tubular conduits. Early embryonic hearts are tubular conduits acting as valveless pumps. It is unclear whether such hearts work as peristaltic or Liebau-effect pumps. During the initial phase of its pumping activity, the originally straight embryonic heart is subjected to deforming forces that produce bending, twisting, kinking, and coiling. This deformation process is called cardiac looping. Its function is traditionally seen as generating a configuration needed for establishment of correct alignments of pulmonary and systemic flow pathways in the mature heart of lung-breathing vertebrates. This idea conflicts with the fact that cardiac looping occurs in all vertebrates, including gill-breathing fishes. We speculate that looping morphogenesis may improve the efficiency of valveless pumping. To test the physical plausibility of this hypothesis, we analyzed the pumping performance of a Liebau-effect pump in straight and looped (kinked) configurations. Compared to the straight configuration, the looped configuration significantly improved the pumping performance of our pump. This shows that looping can improve the efficiency of valveless pumping driven by the Liebau-effect. Further studies are needed to clarify whether this finding may have implications for understanding of the form-function relationship of embryonic hearts.

Kinking and Torsion Can Significantly Improve the Efficiency of Valveless Pumping in Periodically Compressed Tubular Conduits. Implications for Understanding of the Form-Function Relationship of Embryonic Heart Tubes

PubMed Central

Hiermeier, Florian; Männer, Jörg

2017-01-01

Valveless pumping phenomena (peristalsis, Liebau-effect) can generate unidirectional fluid flow in periodically compressed tubular conduits. Early embryonic hearts are tubular conduits acting as valveless pumps. It is unclear whether such hearts work as peristaltic or Liebau-effect pumps. During the initial phase of its pumping activity, the originally straight embryonic heart is subjected to deforming forces that produce bending, twisting, kinking, and coiling. This deformation process is called cardiac looping. Its function is traditionally seen as generating a configuration needed for establishment of correct alignments of pulmonary and systemic flow pathways in the mature heart of lung-breathing vertebrates. This idea conflicts with the fact that cardiac looping occurs in all vertebrates, including gill-breathing fishes. We speculate that looping morphogenesis may improve the efficiency of valveless pumping. To test the physical plausibility of this hypothesis, we analyzed the pumping performance of a Liebau-effect pump in straight and looped (kinked) configurations. Compared to the straight configuration, the looped configuration significantly improved the pumping performance of our pump. This shows that looping can improve the efficiency of valveless pumping driven by the Liebau-effect. Further studies are needed to clarify whether this finding may have implications for understanding of the form-function relationship of embryonic hearts. PMID:29367548

Transmission probabilities of rarefied flows in the application of atmosphere-breathing electric propulsion

NASA Astrophysics Data System (ADS)

Binder, T.; Boldini, P. C.; Romano, F.; Herdrich, G.; Fasoulas, S.

2016-11-01

Atmosphere-Breathing Electric Propulsion systems (ABEP) are currently investigated to utilize the residual atmosphere as propellant for drag-compensating thrusters on spacecraft in (very) low orbits. The key concept for an efficient intake of such a system is to feed a large fraction of the incoming flow to the thruster by a high transmission probability Θ for the inflow while Θ for the backflow should be as low as possible. This is the case for rarefied flows through tube-like structures of arbitrary cross section when assuming diffuse wall reflections inside and after these ducts, and entrance velocities u larger than thermal velocities vt h∝√{kBT /m } . The theory of transmission for free molecular flow through cylinders is well known for u = 0, but less research results are available for u > 0. In this paper, the desired theoretical characteristics of intakes for ABEP are pointed out, a short review of transmission probabilities is given, and results of Monte Carlo simulations concerning Θ are presented. Based on simple algebraic relations, an intake can be optimized in terms of collection efficiency by choosing optimal ducts. It is shown that Θ depends only on non-dimensional values of the duct geometry combined with vth and u. The simulation results of a complete exemplary ABEP configuration illustrate the influence of modeling quality in terms of inflow conditions and inter-particle collisions.

Variations in pulmonary artery occlusion pressure to estimate changes in pleural pressure.

PubMed

Bellemare, Patrick; Goldberg, Peter; Magder, Sheldon A

2007-11-01

A readily available assessment of changes in pleural pressure would be useful for ventilator and fluid management in critically ill patients. We examined whether changes in pulmonary artery occlusion pressure (Ppao) adequately reflect respiratory changes in pleural pressure as assessed by changes in intraesophageal balloon pressure (Peso). We studied patients who had a pulmonary catheter and esophageal balloon surrounding a nasogastric tube as part of their care (n=24). We compared changes in Ppao (dPpao) to changes in Peso (dPeso) by Bland-Altman and regression analysis. Adequacy of balloon placement was assessed by performing Mueller maneuvers and adjusting the position to achieve a ratio of dPeso to change in tracheal pressure (dPtr) of 0.85 or higher. This was achieved in only 14 of the 24 subjects. We also compared dCVP to dPeso. The dPpao during spontaneous breaths and positive pressure breaths gave a good estimate of Peso but generally underestimated dPeso (bias=2.2 +8.2 and -3.9 cmH2O for the whole group). The dCVP was not as good a predictor (bias=2.9 +10.3 and -4.6). In patients who have a pulmonary artery catheter in place dPpao gives a lower estimate of changes in pleural pressure and may be more reliable than dPeso. The dCVP is a less reliable predictor than changes in pleural pressure.

Internal dosimetry of inhaled iodine-131.

PubMed

Kiani Nasab, Mitra; Rafat Motavalli, Laleh; Miri Hakimabad, Hashem

2018-01-01

In this paper, the dose assessment for the iodine inhalation exposure in 19 aerosol sizes and three gas/vapor forms at three levels of thyroid uptake, was performed. Two different modes of work (light vs. heavy) and breathing (nose vs. mouth) for aerosol inhalation were investigated. In order to calculate the cumulated activities per unit of inhaled activity, a combined model which included the latest models of both human respiratory and alimentary tract was developed. The S values for 131 I were computed based on the ICRP adult male and female reference voxel phantoms by the Monte Carlo method. Then, the committed equivalent and committed effective dose coefficients were obtained (The data are available at http://www.um.ac.ir/∼mirihakim). In general, for the nonzero thyroid uptakes, the maximum cumulated activity was found in the thyroid. When the thyroid is blocked, however, the maximum depends on the work and breathing mode and radioisotope form. Overall, the maximum CED coefficient was evaluated for the inhalation of elemental iodine at thyroid uptake of ∼27% (2.8 × 10 -8 Sv/Bq). As for the particle inhalation per se, mouth breathing of 0.6 nm and 0.2 μm AMTD particles showed to have the maximum (2.8 × 10 -8 Sv/Bq) and minimum (6.4 × 10 -9 Sv/Bq) CED coefficients, respectively. Compared to the reference CED coefficients, the authors found an increase of about 58% for inhalation of the aerosols with AMAD of 1 μm and 70% for 5 μm. Copyright © 2017 Elsevier Ltd. All rights reserved.

Intensity noise reduction of a high-power nonlinear femtosecond fiber amplifier based on spectral-breathing self-similar parabolic pulse evolution

NASA Astrophysics Data System (ADS)

Wang, Sijia; Liu, Bowen; Song, Youjian; Hu, Minglie

2016-04-01

We report on a simple passive scheme to reduce the intensity noise of high-power nonlinear fiber amplifiers by use of the spectral-breathing parabolic evolution of the pulse amplification with an optimized negative initial chirp. In this way, the influences of amplified spontaneous emission (ASE) on the amplifier intensity noise can be efficiently suppressed, owing to the lower overall pulse chirp, shorter spectral broadening distance, as well as the asymptotic attractive nature of self-similar pulse amplification. Systematic characterizations of the relative intensity noise (RIN) of a free-running nonlinear Yb-doped fiber amplifier are performed over a series of initial pulse parameters. Experiments show that the measured amplifier RIN increases respect to the decreased input pulse energy, due to the increased amount of ASE noise. For pulse amplification with a proper negative initial chirp, the increase of RIN is found to be smaller than with a positive initial chirp, confirming the ASE noise tolerance of the proposed spectral-breathing parabolic amplification scheme. At the maximum output average power of 27W (25-dB amplification gain), the incorporation of an optimum negative initial chirp (-0.84 chirp parameter) leads to a considerable amplifier root-mean-square (rms) RIN reduction of ~20.5% (integrated from 10 Hz to 10 MHz Fourier frequency). The minimum amplifier rms RIN of 0.025% (integrated from 1 kHz to 5 MHz Fourier frequency) is obtained along with the transform-limited compressed pulse duration of 55fs. To our knowledge, the demonstrated intensity noise performance is the lowest RIN level measured from highpower free-running femtosecond fiber amplifiers.

Upper-airway flow limitation and transcutaneous carbon dioxide during sleep in normal pregnancy.

PubMed

Rimpilä, Ville; Jernman, Riina; Lassila, Katariina; Uotila, Jukka; Huhtala, Heini; Mäenpää, Johanna; Polo, Olli

2017-08-01

Sleep during pregnancy involves a physiological challenge to provide sufficient gas exchange to the fetus. Enhanced ventilatory responses to hypercapnia and hypoxia may protect from deficient gas exchange, but sleep-disordered breathing (SDB) may predispose to adverse events. The aim of this study was to analyze sleep and breathing in healthy pregnant women compared to non-pregnant controls, with a focus on CO 2 changes and upper-airway flow limitation. Healthy women in the third trimester and healthy non-pregnant women with normal body mass index (BMI) were recruited for polysomnography. Conventional analysis of sleep and breathing was performed. Transcutaneous carbon dioxide (TcCO 2 ) was determined for each sleep stage. Flow-limitation was analyzed using the flattening index and TcCO 2 values were recorded for every inspiration. Eighteen pregnant women and 12 controls were studied. Pregnancy was associated with shorter sleep duration and more superficial sleep. Apnea-hypopnea index, arterial oxyhemoglobin desaturation, flow-limitation, snoring or periodic leg movements were similar in the two groups. Mean SaO 2 and minimum SaO 2 were lower and average heart rate was higher in the pregnant group. TcCO 2 levels did not differ between groups but variance of TcCO 2 was smaller in pregnant women during non-rapid eye movement (NREM). TcCO 2 profiles showed transient TcCO 2 peaks, which seem specific to pregnancy. Healthy pregnancy does not predispose to SDB. Enhanced ventilatory control manifests as narrowing threshold of TcCO 2 between wakefulness and sleep. Pregnant women have a tendency for rapid CO 2 increases during sleep which might have harmful consequences if not properly compensated. Copyright © 2017 Elsevier B.V. All rights reserved.

Implications of free breathing motion assessed by 4D-computed tomography on the delivered dose in radiotherapy for esophageal cancer.

PubMed

Duma, Marciana Nona; Berndt, Johannes; Rondak, Ina-Christine; Devecka, Michal; Wilkens, Jan J; Geinitz, Hans; Combs, Stephanie Elisabeth; Oechsner, Markus

2015-01-01

The aim of this study was to assess the effect of breathing motion on the delivered dose in esophageal cancer 3-dimensional (3D)-conformal radiotherapy (3D-CRT), intensity-modulated radiotherapy (IMRT), and volumetric modulated arc therapy (VMAT). We assessed 16 patients with esophageal cancer. All patients underwent 4D-computed tomography (4D-CT) for treatment planning. For each of the analyzed patients, 1 3D-CRT, 1 IMRT, and 1 VMAT (RapidArc-RA) plan were calculated. Each of the 3 initial plans was recalculated on the 4D-CT (for the maximum free inspiration and maximum free expiration) to assess the effect of breathing motion. We assessed the minimum dose (Dmin) and mean dose (Dmean) to the esophagus within the planning target volume, the volume changes of the lungs, the Dmean and the total lung volume receiving at least 40Gy (V40), and the V30, V20, V10, and V5. For the heart we assessed the Dmean and the V25. Over all techniques and all patients the change in Dmean as compared with the planned Dmean (planning CT [PCT]) to the esophagus was 0.48% in maximum free inspiration (CT_insp) and 0.55% in maximum free expiration (CT_exp). The Dmin CT_insp change was 0.86% and CT_exp change was 0.89%. The Dmean change of the lungs (heart) was in CT_insp 1.95% (2.89%) and 3.88% (2.38%) in CT_exp. In all, 4 patients had a clinically relevant change of the dose (≥ 5% Dmean to the heart and the lungs) between inspiration and expiration. These patients had a very cranially or caudally situated tumor. There are no relevant differences in the delivered dose to the regions of interest among the 3 techniques. Breathing motion management could be considered to achieve a better sparing of the lungs or heart in patients with cranially or caudally situated tumors. Copyright © 2015 American Association of Medical Dosimetrists. Published by Elsevier Inc. All rights reserved.

Implications of free breathing motion assessed by 4D-computed tomography on the delivered dose in radiotherapy for esophageal cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Duma, Marciana Nona, E-mail: Marciana.Duma@mri.tum.de; Berndt, Johannes; Rondak, Ina-Christine

2015-01-01

The aim of this study was to assess the effect of breathing motion on the delivered dose in esophageal cancer 3-dimensional (3D)-conformal radiotherapy (3D-CRT), intensity-modulated radiotherapy (IMRT), and volumetric modulated arc therapy (VMAT). We assessed 16 patients with esophageal cancer. All patients underwent 4D-computed tomography (4D-CT) for treatment planning. For each of the analyzed patients, 1 3D-CRT, 1 IMRT, and 1 VMAT (RapidArc—RA) plan were calculated. Each of the 3 initial plans was recalculated on the 4D-CT (for the maximum free inspiration and maximum free expiration) to assess the effect of breathing motion. We assessed the minimum dose (D{sub min})more » and mean dose (D{sub mean}) to the esophagus within the planning target volume, the volume changes of the lungs, the D{sub mean} and the total lung volume receiving at least 40 Gy (V{sub 40}), and the V{sub 30}, V{sub 20}, V{sub 10}, and V{sub 5}. For the heart we assessed the D{sub mean} and the V{sub 25}. Over all techniques and all patients the change in D{sub mean} as compared with the planned D{sub mean} (planning CT [PCT]) to the esophagus was 0.48% in maximum free inspiration (CT-insp) and 0.55% in maximum free expiration (CT-exp). The D{sub min} CT-insp change was 0.86% and CT-exp change was 0.89%. The D{sub mean} change of the lungs (heart) was in CT-insp 1.95% (2.89%) and 3.88% (2.38%) in CT-exp. In all, 4 patients had a clinically relevant change of the dose (≥ 5% D{sub mean} to the heart and the lungs) between inspiration and expiration. These patients had a very cranially or caudally situated tumor. There are no relevant differences in the delivered dose to the regions of interest among the 3 techniques. Breathing motion management could be considered to achieve a better sparing of the lungs or heart in patients with cranially or caudally situated tumors.« less

Voluntary control of breathing does not alter vagal modulation of heart rate

NASA Technical Reports Server (NTRS)

Patwardhan, A. R.; Evans, J. M.; Bruce, E. N.; Eckberg, D. L.; Knapp, C. F.

1995-01-01

Variations in respiratory pattern influence the heart rate spectrum. It has been suggested, hence, that metronomic respiration should be used to correctly assess vagal modulation of heart rate by using spectral analysis. On the other hand, breathing to a metronome has been reported to increase heart rate spectral power in the high- or respiratory frequency region; this finding has led to the suggestion that metronomic respiration enhances vagal tone or alters vagal modulation of heart rate. To investigate whether metronomic breathing complicates the interpretation of heart rate spectra by altering vagal modulation, we recorded the electrocardiogram and respiration from eight volunteers during three breathing trials of 10 min each: 1) spontaneous breathing (mean rate of 14.4 breaths/min); 2) breathing to a metronome at the rate of 15, 18, and 21 breaths/min for 2, 6, and 2 min, respectively; and 3) breathing to a metronome at the rate of 18 breaths/min for 10 min. Data were also collected from eight volunteers who breathed spontaneously for 20 min and breathed metronomically at each subject's mean spontaneous breathing frequency for 20 min. Results from the three 10-min breathing trials showed that heart rate power in the respiratory frequency region was smaller during metronomic breathing than during spontaneous breathing. This decrease could be explained fully by the higher breathing frequencies used during trials 2 and 3 of metronomic breathing. When the subjects breathed metronomically at each subject's mean breathing frequency, the heart rate powers during metronomic breathing were similar to those during spontaneous breathing. Our results suggest that vagal modulation of heart rate is not altered and vagal tone is not enhanced during metronomic breathing.

Engineering bioartificial tracheal tissue using hybrid fibroblast-mesenchymal stem cell cultures in collagen hydrogels.

PubMed

Naito, Hiroshi; Tojo, Takashi; Kimura, Michitaka; Dohi, Yoshiko; Zimmermann, Wolfram-Hubertus; Eschenhagen, Thomas; Taniguchi, Shigeki

2011-02-01

We aimed at providing the first in vitro and in vivo proof-of-concept for a novel tracheal tissue engineering technology. We hypothesized that bioartificial trachea (BT) could be generated from fibroblast and collagen hydrogels, mechanically supported by osteogenically-induced mesenchymal stem cells (MSC) in ring-shaped 3D-hydrogel cultures, and applied in an experimental model of rat trachea injury. Tube-shaped tissue was constructed from mixtures of rat fibroblasts and collagen in custom-made casting molds. The tissue was characterized histologically and mechanically. Ring-shaped tissue was constructed from mixtures of rat MSCs and collagen and fused to the tissue-engineered tubes to function as reinforcement. Stiffness of the biological reinforcement was enhanced by induction of osteogeneic differentiation in MSCs. Osteogenic differentiation was evaluated by assessment of osteocalcin (OC) secretion, quantification of calcium (Ca) deposit, and mechanical testing. Finally, BT was implanted to bridge a surgically-induced tracheal defect. A three-layer tubular tissue structure composed of an interconnected network of fibroblasts was constructed. Tissue collapse was prevented by the placement of MSC-containing ring-shaped tissue reinforcement around the tubular constructs. Osteogenic induction resulted in high OC secretion, high Ca deposit, and enhanced construct stiffness. Ultimately, when BT was implanted, recipient rats were able to breathe spontaneously.

How can we reduce alcohol-related road crash deaths among young Australians?

PubMed

Hall, Wayne D; Wallace, Angela L; Cobiac, Linda J; Doran, Christopher M; Vos, Theo

2010-04-19

In the United States, policy experiments over a 20-year period have demonstrated that road crash deaths among young adults can be substantially reduced by raising the minimum legal drinking age to 21 years. A recent evaluation of the cost-effectiveness of policies for reducing alcohol-related harm in Australia found that, if the US experience were to be replicated in Australia, raising the minimum legal drinking age would be more cost-effective than random breath testing and drink-driving campaigns. Given the major political obstacles to increasing the minimum legal drinking age, we propose another policy that could achieve a similar reduction in road crash deaths - requiring licensed drivers to maintain a blood alcohol concentration (BAC) of zero until at least the age of 21 years (close to the current policy of zero BAC until age 22 years in Victoria), and preferably until 25 years. This would allow young Australians to drink or drive but not to combine these activities for at least the first several years of driving. If all Australian jurisdictions had adopted this policy in 2003, 17 deaths could have been be averted among young Australians as they aged from 18 to 21 years and many more serious injuries could have been prevented each year. If we had enforced a zero BAC until age 25, the number of deaths averted until age 25 years could have been as high as 50.

The parasitophorous vacuole of Encephalitozoon cuniculi: biogenesis and characteristics of the host cell-pathogen interface.

PubMed

Bohne, Wolfgang; Böttcher, Karin; Gross, Uwe

2011-06-01

Microsporidia are obligate intracellular fungal pathogens of increasing importance in immunocompromised patients. They have developed a unique invasion mechanism, which is based on the explosive discharge of a hollow tubulus, the so-called polar tube. The infectious sporoplasm is subsequently extruded through this flexible tube and injected into the host cell. The model microsporidium Encephalitozoon cuniculi is a paradigm of a fungus with an extreme host cell dependency. This human pathogen possesses one of the smallest eukaryotic genomes (<3MB) identified so far and has reduced its own biosynthetic pathways to a minimum, thus depending on an efficient supply of metabolites from the host cell. E. cuniculi spends its entire intracellular life cycle inside a parasitophorous vacuole (PV), which is formed during invasion. We have provided here an overview of the biogenesis and characteristics of this important host cell-pathogen interface and suggest in this context a modified model for E. cuniculi invasion. According to the model, the host cell plasma membrane is not pierced by the polar tube, but is pushed at the contact site into the cell interior by the mechanical force of the expelled polar tube. This results in a channel-like invagination of the plasma membrane, from which finally the parasitophorous vacuole is pinched-off. Copyright © 2011 Elsevier GmbH. All rights reserved.

Task-Driven Tube Current Modulation and Regularization Design in Computed Tomography with Penalized-Likelihood Reconstruction.

PubMed

Gang, G J; Siewerdsen, J H; Stayman, J W

2016-02-01

This work applies task-driven optimization to design CT tube current modulation and directional regularization in penalized-likelihood (PL) reconstruction. The relative performance of modulation schemes commonly adopted for filtered-backprojection (FBP) reconstruction were also evaluated for PL in comparison. We adopt a task-driven imaging framework that utilizes a patient-specific anatomical model and information of the imaging task to optimize imaging performance in terms of detectability index ( d' ). This framework leverages a theoretical model based on implicit function theorem and Fourier approximations to predict local spatial resolution and noise characteristics of PL reconstruction as a function of the imaging parameters to be optimized. Tube current modulation was parameterized as a linear combination of Gaussian basis functions, and regularization was based on the design of (directional) pairwise penalty weights for the 8 in-plane neighboring voxels. Detectability was optimized using a covariance matrix adaptation evolutionary strategy algorithm. Task-driven designs were compared to conventional tube current modulation strategies for a Gaussian detection task in an abdomen phantom. The task-driven design yielded the best performance, improving d' by ~20% over an unmodulated acquisition. Contrary to FBP, PL reconstruction using automatic exposure control and modulation based on minimum variance (in FBP) performed worse than the unmodulated case, decreasing d' by 16% and 9%, respectively. This work shows that conventional tube current modulation schemes suitable for FBP can be suboptimal for PL reconstruction. Thus, the proposed task-driven optimization provides additional opportunities for improved imaging performance and dose reduction beyond that achievable with conventional acquisition and reconstruction.

The delivery of chlorofluorocarbon-propelled versus hydrofluoroalkane-propelled beclomethasone dipropionate aerosol to the mechanically ventilated patient: a laboratory study.

PubMed

Mitchell, Jolyon P; Nagel, Mark W; Wiersema, Kimberly J; Doyle, Cathy C; Migounov, Vladimir A

2003-11-01

We describe a laboratory investigation comparing the delivery of chlorofluorocarbon (CFC)- and hydrofluoroalkane (HFA)-formulated beclomethasone dipropionate (BDP) by metered-dose inhaler and holding chamber (AeroChamber HC MV) in a simulation of a mechanically ventilated adult patient. We equipped each HC MV (n = 5) with an 8.0 mm diameter endotracheal tube (ETT), locating the HC MV in the inspiratory limb of a breathing circuit linked to a mechanical ventilator set to simulate tidal breathing at tidal volume = 830 mL, respiratory rate = 15 breaths/min, inspiratory-expiratory ratio of 1:2.1, peak inspiratory pressure = 20 cm H(2)O. Temperature and humidity settings were 35+/-1 degrees C and 100% relative humidity (close to body conditions). We compared delivery of 5-actuations of CFC- and HFA-BDP (both 50 microg/actuation), measuring total emitted mass captured by a filter at the distal end of the ETT. In a separate study, we inserted the distal end of the ETT within the entry cone of a cascade impactor so that the aerosol particle size distribution could be determined with the circuit at similar environmental conditions as described previously. We made benchmark measurements with circuit temperature and humidity at room ambient conditions (21+/-1 degrees C and 54+/-5% RH respectively). Total emitted mass (5 measurements/device) was significantly greater for HFA-BDP (14.1+/-1.1 microg/actuation) compared with CFC-BDP (2.4+/-0.8 microg/actuation) (paired t test, p < 0.001). More HFA-BDP (2.7 +/- 0.2 microg/actuation) was lost from the delivery system during exhalation (0.9 +/- 0.4 microg/actuation for CFC-BDP) (p < 0.001). The mass median aerodynamic diameter (MMAD) increased from 1.2 microm (room ambient) to 2.8 microm (higher temperature and humidity conditions) for HFA-BDP. In contrast, MMAD for CFC-BDP remained close to 4.6 microm under either condition, but particles finer than about 4.0 microm increased in size when the circuit was saturated. Total emitted mass for HFA-BDP was increased by a factor of 5.8 compared with CFC-BDP, due largely to the finer particle size distribution of the HFA-based solution formulation. Additional water vapor required to operate the breathing circuit at close to body conditions resulted in fine particle growth with both formulations.

Analysis of breath volatile organic compounds in children with chronic liver disease compared to healthy controls.

PubMed

Eng, Katharine; Alkhouri, Naim; Cikach, Frank; Patel, Nishaben; Yan, Chen; Grove, David; Lopez, Rocio; Rome, Ellen; Dweik, Raed A

2015-04-20

Breath testing is increasingly being used as a non-invasive diagnostic tool for disease states across medicine. The purpose of this study was to compare the levels of volatile organic compounds (VOCs) as measured by mass spectrometry in healthy children and children with chronic liver disease (CLD). Patients between the ages of 6 and 21 were recruited for the study. Control subjects were recruited from a general pediatric population during well-child visits, while patients with CLD were recruited from pediatric gastroenterology clinic visits. The diagnosis of CLD was confirmed by clinical, laboratory, and/or histologic data. A single exhaled breath was collected and analyzed by means of selected-ion flow-tube mass spectrometry per protocol. A total of 104 patients were included in the study (49 with CLD and 55 healthy controls). Of the patients with CLD, 20 had advanced liver fibrosis (F3-F4). In the CLD cohort, levels of exhaled 1-decene, 1-heptene, 1-octene and 3 methylhexane were found to be significantly higher when compared to the control population (p < 0.001, p = 0.035, p < 0.001 and p = 0.004, respectively). Exhaled 1-nonene, (E)-2-nonene, and dimethyl sulfide levels were found to be significantly lower in patients with CLD patients when compared to controls (p < 0.001, p < 0.001 and p = 0.007, respectively). By utilizing a combination of five of the VOCs, the accuracy for predicting the presence of CLD was excellent (AUROC = 0.97). Our study demonstrates that children with CLD have a unique pattern of exhaled VOCs. Utilization of a combination of these VOCs represents a promising non-invasive diagnostic tool and may provide further insight into the pathophysiologic processes and pathways leading to pediatric liver disease. Further analysis of these compounds in external cohorts are needed to validate our findings.

Work of breathing using different interfaces in spontaneous positive pressure ventilation: helmet, face-mask, and endotracheal tube.

PubMed

Oda, Shinya; Otaki, Kei; Yashima, Nozomi; Kurota, Misato; Matsushita, Sachiko; Kumasaka, Airi; Kurihara, Hutaba; Kawamae, Kaneyuki

2016-08-01

Noninvasive positive pressure ventilation (NPPV) using a helmet is expected to cause inspiratory trigger delay due to the large collapsible and compliant chamber. We compared the work of breathing (WOB) of NPPV using a helmet or a full face-mask with that of invasive ventilation by tracheal intubation. We used a lung model capable of simulating spontaneous breathing (LUNGOO; Air Water Inc., Japan). LUNGOO was set at compliance (C) = 50 mL/cmH2O and resistance (R) = 5 cmH2O/L/s for normal lung simulation, C = 20 mL/cmH2O and R = 5 cmH2O/L/s for restrictive lung, and C = 50 mL/cmH2O and R = 20 cmH2O/L/s for obstructive lung. Muscle pressure was fixed at 25 cmH2O and respiratory rate at 20 bpm. Pressure support ventilation and continuous positive airway pressure were performed with each interface placed on a dummy head made of reinforced plastic that was connected to LUNGOO. We tested the inspiratory WOB difference between the interfaces with various combinations of ventilator settings (positive end-expiratory pressure 5 cmH2O; pressure support 0, 5, and 10 cmH2O). In the normal lung and restrictive lung models, WOB decreased more with the face-mask than the helmet, especially when accompanied by the level of pressure support. In the obstructive lung model, WOB with the helmet decreased compared with the other two interfaces. In the mixed lung model, there were no significant differences in WOB between the three interfaces. NPPV using a helmet is more effective than the other interfaces for WOB in obstructive lung disease.