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Magnetic Resonance Imaging Dec 2005The aim of this experimental study was to evaluate the potential of a simple expiration technique by means of magnetic resonance imaging (MRI) in an animal model to...
PURPOSE
The aim of this experimental study was to evaluate the potential of a simple expiration technique by means of magnetic resonance imaging (MRI) in an animal model to detect pulmonary air-trapping areas after artificial bronchial obstruction.
MATERIAL AND METHODS
Sixteen pigs were evaluated by means of a modified T1-weighted FLASH with fat saturation in respiratory arrest (TR=4.6 ms, TE=1.8 ms, alpha=10 degrees, S.D.=3-5 mm). A measurement of the signal intensity (SI) in the peripheral lung tissue was made in both inspiration and expiration before and after inhalation of 2 ml of 0.5% acetylcholine to simulate a bronchial obstruction. A final measurement of the lung SI was also made after bronchospasmolytic induction through salbutamol (beta2-mimetic bronchodilator).
RESULTS
In expiration, a mean SI increase in peripheral lung tissue of about 183% was seen in comparison to inspiration (mean SI increase of 11-32). After inhalation of 0.5% acetylcholine, the expirational signal increase in peripheral lung tissue was only 114% of the original SI. The expirational signal homogeneity decreased after inhalation of acetylcholine. After inhalation of salbutamol, the lung tissue signal elevation in expiration was 193%.
CONCLUSION
We interpret the low expiratory signal elevation after acetylcholine inhalation as a result of an air-trapped bronchial constriction in certain areas. The simple expiratory technique in an animal model showed that it is suitable to demonstrate obstructive air trapping using MRI.
Topics: Acetylcholine; Albuterol; Animals; Bronchodilator Agents; Lung Diseases, Obstructive; Magnetic Resonance Imaging; Pulmonary Ventilation; Respiration; Swine
PubMed: 16376182
DOI: 10.1016/j.mri.2005.10.001 -
Nano Letters Apr 2010The details of air nanobubble trapping at the interface between water and a nanostructured hydrophobic silicon surface are investigated using X-ray scattering and...
The details of air nanobubble trapping at the interface between water and a nanostructured hydrophobic silicon surface are investigated using X-ray scattering and contact angle measurements. Large-area silicon surfaces containing hexagonally packed, 20 nm wide hydrophobic cavities provide ideal model surfaces for studying the morphology of air nanobubbles trapped inside cavities and its dependence on the cavity depth. Transmission small-angle X-ray scattering measurements show stable trapping of air inside the cavities with a partial water penetration of 5-10 nm into the pores, independent of their large depth variation. This behavior is explained by consideration of capillary effects and the cavity geometry. For parabolic cavities, the liquid can reach a thermodynamically stable configuration-a nearly planar nanobubble meniscus-by partially penetrating into the pores. This microscopic information correlates very well with the macroscopic surface wetting behavior.
Topics: Air; Hydrophobic and Hydrophilic Interactions; Nanostructures; Nanotechnology; Particle Size; Silicon; Surface Properties
PubMed: 20180525
DOI: 10.1021/nl9042246 -
Archives of Iranian Medicine Mar 2011The purpose of this study was to examine whether the degree of air trapping in high resolution computed tomography (HRCT) of patients with histories of sulfur mustard...
OBJECTIVE
The purpose of this study was to examine whether the degree of air trapping in high resolution computed tomography (HRCT) of patients with histories of sulfur mustard gas exposure during suspended full expiration correlated with various parameters of the cardiopulmonary exercise test as the gold standard for assessment of pulmonary function.
METHODS
In this analytic study 75 male patients, each with a history of sulfur mustard gas exposure, were investigated. Each participant underwent an incremental cardiopulmonary exercise test, pulmonary function test and arterial oxygen saturation for hemoglobin measurement. For HRCT examination, both lungs were divided into three parts (upper, middle, and lower) and in each part images were separately observed from the involved area point of view (<25% ≤6/24; >25% ≥6/24).
RESULTS
A total of 49.3% of the patients (37/75) had evidence of air trapping in over 25% of their lung segments. The mean age±SD in the patients with air trapping of =25% or <25% were 41.1±6.8 and 39.7±4.0 years, respectively (P=0.281). In our study there was no significant difference in pulmonary function test findings (FEV1, FVC and FEV1/FVC) between the two groups. There was no significant correlation with air trapping of =25% and any of the exercise test parameters. Also, no correlation was found between significant air trapping and exercise test findings in maximum exercise and anaerobic situations.
CONCLUSIONS
No correlation was found between HRCT and cardiopulmonary exercise test findings. HRCT is neither pathognomic of the disease nor a good predictor of disease severity but it might be suggestive of mustard lung injuries.
Topics: Adult; Air; Chemical Warfare Agents; Chronic Disease; Exercise Test; Exhalation; Humans; Lung Diseases; Male; Middle Aged; Mustard Gas; Respiratory Function Tests; Severity of Illness Index; Tomography, X-Ray Computed
PubMed: 21361713
DOI: No ID Found -
Journal of Thoracic Imaging Nov 2010First, to test the hypothesis that air trapping in diseased patients follows a gravitational gradient and is more extensive in dependent than in nondependent lung...
PURPOSE
First, to test the hypothesis that air trapping in diseased patients follows a gravitational gradient and is more extensive in dependent than in nondependent lung regions. Second, to test the hypothesis that the dependent lung regions on combined supine and prone expiratory computed tomography (CT) examinations will show more air trapping than would a supine expiratory CT examination alone.
MATERIALS AND METHODS
For this ethics committee-approved study, supine and prone multidetector-row CT (4×1 mm collimation, 0.5 s rotation time, 140 kVp, and effective 80 mAs) was performed at full end-expiration on 47 lung transplant recipients (mean age 41±12 y; 18 without bronchiolitis, 18 with potential bronchiolitis, and 11 with bronchiolitis). The extent of air trapping was visually quantified in the supine and prone positions, and in dependent and nondependent lung regions. Individual air trapping scores from these regions were thus available and could be combined for later analysis. Differences in the extent of air trapping between the positions and regions were tested with a Wilcoxon signed-rank test.
RESULTS
Air trapping was significantly more extensive in the combined dependent lung regions than in the combined nondependent lung regions (15.00% vs. 5.77%; P<0.001). Air trapping was also significantly more extensive in the combined dependent regions than in the supine body position (15.00% vs. 7.50%; P<0.001). No statistically significant difference in the extent of air trapping was found between the supine and the prone positions (7.50% vs. 12.14%; P=0.735).
CONCLUSIONS
In patients with suspected or overt small airways disease, air trapping follows a gravitational gradient. A change from the supine to the prone position can make air trapping visible in formerly nondependent lung regions. The combined readings from supine and prone CT examinations in dependent lung regions show more air trapping than a standard supine CT examination alone.
Topics: Adult; Air; Bronchiolitis Obliterans; Exhalation; Female; Gravitation; Humans; Image Processing, Computer-Assisted; Lung; Lung Transplantation; Male; Middle Aged; Observer Variation; Posture; Prone Position; Prospective Studies; Respiratory Function Tests; Supine Position; Tomography, X-Ray Computed; Young Adult
PubMed: 20395871
DOI: 10.1097/RTI.0b013e3181cbc28b -
Insects Nov 2022Assemblages of insects need to be quantitatively sampled in the context of various research questions. Light trapping is the most widely used method for sampling...
Assemblages of insects need to be quantitatively sampled in the context of various research questions. Light trapping is the most widely used method for sampling nocturnal Lepidoptera. Attracting moths to sugar baits offers a viable alternative. However, this method is rarely used in professional research despite its popularity among amateur lepidopterists. As the activity of insects is strongly dependent on ambient conditions, the sensitivity of any trapping method to weather parameters needs to be known for the quantitative interpretation of trapping results. In the present paper, we report data on the weather dependence of moth catches obtained by automatic bait traps. The study was performed in Estonia, representing the European hemiboreal forest zone. Portable weather stations set up next to each of the traps were used for collecting weather data. Both abundance and diversity of the moths in the catches depended strongly positively on temperature and negatively on air humidity. Diversity was also negatively correlated with air pressure and positively with the change in pressure during the night. The results show that in situ recording of weather parameters in connection to insect trapping provides useful insights for the study of insect behaviour and the interpretation of the results of monitoring projects.
PubMed: 36554997
DOI: 10.3390/insects13121087 -
Analytical Sciences : the International... Jan 2024The comparative evaluation of two aerosol droplets of different chemical compositions using the dual-beam laser trapping technique can be employed for highly sensitive...
The comparative evaluation of two aerosol droplets of different chemical compositions using the dual-beam laser trapping technique can be employed for highly sensitive and accurate measurements of the water activities of such droplets. However, it is technically difficult to load droplets of different chemical compositions into adjacent optical traps that are only a few tens of micrometers apart. To overcome this challenge, a chamber with an overhanging roof was created. This roof prevented the initially trapped droplets from being contaminated by aerosol droplets that were subsequently introduced into the chamber. Herein, we report the simultaneous laser trapping of an aqueous ammonium sulfate (AS) droplet and an aqueous succinic acid (SA) droplet in air using the dual-beam laser trapping technique. Two droplets were successfully fused through optical manipulation to form a mixed inorganic/organic droplet in air. This experimental approach is advantageous because it forms mixed inorganic/organic droplets under constant relative humidity (RH) conditions. However, in previous studies, it was necessary to compensate for changes in RH prior to and after droplet fusion. To assess the validity of theoretical predictions of the water activity of droplets containing AS and SA, the equilibrium radii of the droplet were compared with those calculated using certain theoretical models.
PubMed: 37819572
DOI: 10.1007/s44211-023-00439-w -
Langmuir : the ACS Journal of Surfaces... Feb 2020Surface texturing is an easy way to control wettability as well as bacterial adhesion. Air trapped in the surface texture of an immersed sample was often proposed as the...
Surface texturing is an easy way to control wettability as well as bacterial adhesion. Air trapped in the surface texture of an immersed sample was often proposed as the origin of the low adhesion of bacteria to surfaces showing superhydrophobic properties. In this work, we identified two sets of femtosecond laser processing parameters that led to extreme superhydrophobic textures on a silicone elastomer but showed opposite behavior against (S. aureus, ATCC 25923) over a short incubation times (6 h). The main difference from most of the previous studies was that the air trapping was not evaluated from the extrapolation of the results of the classical sessile drop technique but from the drop rebound and Wilhelmy plate method. Additionally, all wetting tests were performed with bacteria culture medium and at 37 °C in the case of the Wilhelmy plate method. Following this approach, we were able to study the formation of the liquid/silicone interface and the associated air trapping for immersed samples that is, by far, most representative of the cell culture conditions than those associated with the sessile drop technique. Finally, the conversion of these superhydrophobic coatings into superhydrophilic ones revealed that air trapping is not a necessary condition to avoid retention on one of these two textured surfaces at short incubation times.
Topics: Air; Bacterial Adhesion; Hydrophobic and Hydrophilic Interactions; Lasers; Silicone Elastomers; Staphylococcus aureus; Wettability
PubMed: 31887046
DOI: 10.1021/acs.langmuir.9b03170 -
Nature Communications Mar 2016Confinement of living microorganisms and self-propelled particles by an external trap provides a means of analysing the motion and behaviour of active systems....
Confinement of living microorganisms and self-propelled particles by an external trap provides a means of analysing the motion and behaviour of active systems. Developing a tweezer with a trapping radius large compared with the swimmers' size and run length has been an experimental challenge, as standard optical traps are too weak. Here we report the novel use of an acoustic tweezer to confine self-propelled particles in two dimensions over distances large compared with the swimmers' run length. We develop a near-harmonic trap to demonstrate the crossover from weak confinement, where the probability density is Boltzmann-like, to strong confinement, where the density is peaked along the perimeter. At high concentrations the swimmers crystallize into a close-packed structure, which subsequently 'explodes' as a travelling wave when the tweezer is turned off. The swimmers' confined motion provides a measurement of the swim pressure, a unique mechanical pressure exerted by self-propelled bodies.
Topics: Acoustics; Air; Crystallization; Kinetics; Latex; Models, Statistical; Motion; Nanoparticles; Optical Tweezers; Stochastic Processes; Water
PubMed: 26961816
DOI: 10.1038/ncomms10694 -
Scientific Reports Mar 2021Flapping flight is one of the most costly forms of locomotion in animals. To limit energetic expenditures, flying insects thus developed multiple strategies. An...
Flapping flight is one of the most costly forms of locomotion in animals. To limit energetic expenditures, flying insects thus developed multiple strategies. An effective mechanism to reduce flight power expenditures is the harvesting of kinetic energy from motion of the surrounding air. We here show an unusual mechanism of energy harvesting in an insect that recaptures the rotational energy of air vortices. The mechanism requires pronounced chordwise wing bending during which the wing surface momentary traps the vortex and transfers its kinetic energy to the wing within less than a millisecond. Numerical and robotic controls show that the decrease in vortex strength is minimal without the nearby wing surface. The measured energy recycling might slightly reduce the power requirements needed for body weight support in flight, lowering the flight costs in animals flying at elevated power demands. An increase in flight efficiency improves flight during aversive manoeuvring in response to predation and long-distance migration, and thus factors that determine the worldwide abundance and distribution of insect populations.
Topics: Air Movements; Animals; Biomechanical Phenomena; Drosophila; Energy Metabolism; Flight, Animal; Models, Biological; Wings, Animal
PubMed: 33772058
DOI: 10.1038/s41598-021-86359-z -
Scientific Reports Sep 2018The leakage of sound waves in a resonance based rainbow trapping device prevents the sound wave being trapped in a specific location. In this study, we report a design...
The leakage of sound waves in a resonance based rainbow trapping device prevents the sound wave being trapped in a specific location. In this study, we report a design of sound trapping device based on coupled Helmholtz resonators, loaded to an air waveguide, which can effectively tackle the wave leakage issue. We show that coupled resonators structure can generate dips in the transmission spectrum by an analytical model derived from Newton's second law and numerical analysis based on finite-element method. An effective medium theory is derived, which shows that coupled resonators cause a negative effective bulk modulus near the resonance frequency and induce flat bands that give rise to the confinement of the incoming wave inside the resonators. We compute the transmission spectra and band diagram from the effective medium theory, which are consistent with the simulation results. Trapping and high absorption of sound wave energy are demonstrated with our designed device.
PubMed: 30218005
DOI: 10.1038/s41598-018-32135-5