Search results for "aerosols"
showing 10 items of 105 documents
Computational Study of the Effect of Glyoxal–Sulfate Clustering on the Henry’s Law Coefficient of Glyoxal
2014
We have used quantum chemical methods to investigate the molecular mechanism behind the recently reported ( Kampf , C. J. ; Environ. Sci. Technol . 2013 , 47 , 4236 - 4244 ) strong dependence of the Henry's law coefficient of glyoxal (C2O2H2) on the sulfate concentration of the aqueous phase. Although the glyoxal molecule interacts only weakly with sulfate, its hydrated forms (C2O3H4 and C2O4H6) form strong complexes with sulfate, displacing water molecules from the solvation shell and increasing the uptake of glyoxal into sulfate-containing aqueous solutions, including sulfate-containing aerosol particles. This promotes the participation of glyoxal in reactions leading to secondary organic…
The 2009 Edition of the GEISA Spectroscopic Database
2011
The updated 2009 edition of the spectroscopic database GEISA (Gestion et Etude des Informations Spectroscopiques Atmosphériques; Management and Study of Atmospheric Spectroscopic Information) is described in this paper. GEISA is a computer-accessible system comprising three independent sub-databases devoted, respectively, to: line parameters, infrared and ultraviolet/visible absorption cross-sections, microphysical and optical properties of atmospheric aerosols. In this edition, 50 molecules are involved in the line parameters sub-database, including 111 isotopologues, for a total of 3,807,997 entries, in the spectral range from 10-6 to 35,877.031cm-1.The successful performances of the new …
Reactive oxygen species formed in aqueous mixtures of secondary organic aerosols and mineral dust influencing cloud chemistry and public health in th…
2017
Mineral dust and secondary organic aerosols (SOA) account for a major fraction of atmospheric particulate matter, affecting climate, air quality and public health. How mineral dust interacts with SOA to influence cloud chemistry and public health, however, is not well understood. Here, we investigated the formation of reactive oxygen species (ROS), which are key species of atmospheric and physiological chemistry, in aqueous mixtures of SOA and mineral dust by applying electron paramagnetic resonance (EPR) spectrometry in combination with a spin-trapping technique, liquid chromatography-tandem mass spectrometry (LC-MS/MS), and a kinetic model. We found that substantial amounts of ROS includi…
Microbiology and atmospheric processes: research challenges concerning the impact of airborne micro-organisms on the atmosphere and climate
2011
Cet article a fait l'objet d'une discussion dans "Morris, C. E., Sands, D. C., Bardin, M., Jaenicke, R., Vogel, B., Leyronas, C., Ariya, P. A., and Psenner, R.: Microbiology and atmospheric processes: an upcoming era of research on bio-meteorology, Biogeosciences Discuss., 5, 191-212, doi:10.5194/bgd-5-191-2008, 2008."; International audience; For the past 200 years, the field of aerobiology has explored the abundance, diversity, survival and transport of micro-organisms in the atmosphere. Micro-organisms have been explored as passive and severely stressed riders of atmospheric transport systems. Recently, an interest in the active roles of these micro-organisms has emerged along with prop…
Potent bronchoprotective effect of deep inspiration and its absence in asthma
2000
In the absence of deep inspirations, healthy individuals develop bronchoconstriction with methacholine inhalation. One hypothesis is that deep inspiration results in bronchodilation. In this study, we tested an alternative hypothesis, that deep inspiration acts as a bronchoprotector. Single-dose methacholine bronchoprovocations were performed after 20 min of deep breath inhibition, in nine healthy subjects and in eight asthmatics, to establish the dose that reduces forced expiratory volume in 1 s by >15%. The provocation was repeated with two and five deep inspirations preceding methacholine. Additional studies were carried out to assess optimization and reproducibility of the protocol …
Effects of Inhaled Fenoterol on the Circadian Rhythm of Expiratory Flow in Allergic Bronchial Asthma
1983
Metered-dose aerosol treatment with fenoterol for three consecutive days, in eight patients suffering from allergic asthma, caused the disappearance of FEV1 and MEF50 circadian rhythm. We attribute such behavior to the suppression of the bronchomotor tone induced by fenoterol. The administration on different days of a single dose of fenoterol aerosol in another group of eight patients pointed out the variability of the effects of the drug at different hours of the day. We believe the results obtained are important for a better dosage and time distribution of the therapy with beta2 agonists.
Systemic chemotherapy and pressurized intraperitoneal aerosol chemotherapy (PIPAC): A bidirectional approach for gastric cancer peritoneal metastasis
2019
Abstract Background Few patients affected by gastric cancer peritoneal metastasis (GCPM) are offered locoregional treatment, despite several proof-of-efficacy trials. Pressurized intraperitoneal aerosol chemotherapy (PIPAC) has emerged in recent years as a promising tool to control peritoneal carcinomatosis. The combination of PIPAC with systemic chemotherapy may offer a greater clinical benefit than standard treatment alone. Methods A single-center cohort of 28 consecutive patients affected by GCPM was scheduled for bidirectional treatment, comprising PIPAC and systemic chemotherapy, from September 2017 to September 2019. Data recorded included safety, efficacy and survival outcomes. Ascit…
Atherosclerosis and Cerebral Ischemic Attacks: Intakes of Cerebrography With Xenon133 Inhaled and Platelet Tests in the Diagnosis, Clinical and Thera…
1984
A study of patients to develop the significance of the role of the blood plate lets in the recurrence of transient cerebral ischemic attacks in patients with cerebral atheromatous, develop the effectiveness of dipyridamole in the prophy lactic therapeutic regimen. In the group treated with dipyridamole, a 76.3% clinical improvement was recorded (mean increases of 11.2 ml/min. and 11.4 ml/min. of the cerebral hemispheric flows), 15.8% of cases stabilized (mean increases of 1.7 ml/min. and 1.2 ml/min.) and 7.9% failures (mean decreases of 10.4 ml/min. and 14.3 ml/min.) of these same flows. The cerebrography with xenon 133 inhaled as well as the platelet tests used, constitute unfailing means…
Mass Output and Particle Size Distribution of Glucocorticosteroids Emitted from Different Inhalation Devices Depending on Various Inspiratory Paramet…
2002
Efficient inhalation therapy depends on successful delivery of the drug to the lung. The efficacy of drug delivery is not only influenced by the characteristics of the inhalation device, but also by the patient's handling of the device and by the inspiratory maneuver achieved through the device. We analyzed the output characteristics of three different chlorofluorocarbon (CFC)-free breath-actuated inhalers for inhaled glucocorticosteroids (BUD Turbohaler, FP Diskus/Accuhaler and HFA-BDP Autohaler, respectively). Mass output and particle size distribution of drug aerosol delivered by the inhalers were determined depending on different inhalation parameters in vitro using an Andersen cascade …
Aerosol properties of the Eyjafjallajökull ash derived from sun photometer and satellite observations over the Iberian Peninsula
2012
The Eyjafjallajökull ash that crossed over Spain and Portugal on 6e12 May 2010 has been monitored by a set of operational sun photometer sites within AERONET-RIMA and satellite sensors. The sun photometer observations (aerosol optical depth, coarse mode concentrations) and ash products from IASI and SEVIRI satellite sensors, together with FLEXPART simulations of particle transport, allow identifying the volcanic aerosols. The aerosol columnar properties derived from inversions were investigated, indicating specific properties, especially regarding the absorption. The single scattering albedo was high (0.95 at 440 nm) and nearly wavelength independent, although with slight decrease with wave…