keyword
MENU ▼
Read by QxMD icon Read
search

aerosol particle

keyword
https://www.readbyqxmd.com/read/29154770/density-and-shape-factor-terms-in-stokes-equation-for-aerodynamic-behavior-of-aerosols
#1
Anthony J Hickey, David A Edwards
Pharmaceutical aerosols are used to treat many pulmonary diseases. The use of low density powders has proven useful to support efficient drug delivery. Measurements must account for the low density, spherical particle features contributing to aerodynamic behavior. Ideally, the aerodynamic particle size distribution (APSD) is measured experimentally. Without formal measurement of APSD, calculations may be performed using surrogate measures such as bulk or tapped density and dynamic shape factor in Stokes' equation...
November 14, 2017: Journal of Pharmaceutical Sciences
https://www.readbyqxmd.com/read/29154207/particle-size-distribution-and-respiratory-deposition-estimates-of-airborne-perfluoroalkyl-acids-during-the-haze-period-in-the-megacity-of-shanghai
#2
Mengjie Guo, Yan Lyu, Tingting Xu, Bo Yao, Weihua Song, Mei Li, Xin Yang, Tiantao Cheng, Xiang Li
This study presents the particle size distribution and respiratory deposition estimates of airborne perfluoroalkyl acids (PFAAs) during the haze period. Size-segregated haze aerosols were collected from an urban location in Shanghai using an eight-stage air sampler. The samples were analyzed for eight PFAAs using ultra-high-performance liquid chromatography tandem triple quadrupole mass spectrometry. The quantification results showed that the concentrations of particle-bound Σ 8PFAAs ranged from 0.26 to 1...
November 16, 2017: Environmental Pollution
https://www.readbyqxmd.com/read/29150676/severe-pollution-in-china-amplified-by-atmospheric-moisture
#3
Xuexi Tie, Ru-Jin Huang, Junji Cao, Qiang Zhang, Yafang Cheng, Hang Su, Di Chang, Ulrich Pöschl, Thorsten Hoffmann, Uli Dusek, Guohui Li, Douglas R Worsnop, Colin D O'Dowd
In recent years, severe haze events often occurred in China, causing serious environmental problems. The mechanisms responsible for the haze formation, however, are still not well understood, hindering the forecast and mitigation of haze pollution. Our study of the 2012-13 winter haze events in Beijing shows that atmospheric water vapour plays a critical role in enhancing the heavy haze events. Under weak solar radiation and stagnant moist meteorological conditions in winter, air pollutants and water vapour accumulate in a shallow planetary boundary layer (PBL)...
November 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29148753/kinetics-of-the-aqueous-phase-reactions-of-atmospherically-relevant-monoterpene-epoxides
#4
Diego A Cortes, Matthew J Elrod
Laboratory and field measurements have demonstrated that an isoprene-derived epoxide intermediate (IEPOX) is the origin of a wide range of chemical species found in ambient secondary organic aerosol (SOA). In order to explore the potential relevance of a similar mechanism for the formation of monoterpene-derived SOA, nuclear magnetic resonance techniques were used to study kinetics and reaction products of the aqueous phase reactions of several monoterpene epoxides: β-pinene oxide, limonene oxide, and limonene dioxide...
November 17, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/29148736/formation-of-metal-cyanide-complexes-in-deliquescent-airborne-particles-a-new-possible-sink-for-hcn-in-urban-environments
#5
Chiara Giorio, Daniele Marton, Gianni Formenton, Andrea Tapparo
Hydrogen cyanide is a ubiquitous gas in the atmosphere and a biomass burning tracer. Reactive gasses can be adsorbed onto aerosol particles where they can promote heterogeneous chemistry. In the present study, we report for the first time on the measurement and speciation of cyanides in atmospheric aerosol. Filter samples were collected at an urban background site in the city center of Padua (Italy), extracted and analyzed with headspace gas chromatography and nitrogen-phosphorous detection. The results showed that strongly bound cyanides were present in all aerosol samples at a concentration ranging between 0...
November 17, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/29148717/raman-spectroscopy-of-single-light-absorbing-carbonaceous-particles-levitated-in-air-using-an-annular-laser-beam
#6
Masaru Uraoka, Keisuke Maegawa, Shoji Ishizaka
A laser trapping technique is a powerful means to investigate the physical and chemical properties of single aerosol particles in a non-contact manner. However, optical trapping of strongly light-absorbing particles such as black carbon or soot is quite difficult because the repulsive force caused by heat is orders of magnitude larger than the attractive force of radiation pressure. In this study, a laser trapping and Raman microspectroscopy system using an annular laser beam was constructed to achieve non-contact levitation of single light-absorbing particles in air...
November 17, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/29144737/infant-and-adult-inhalation-exposure-to-resuspended-biological-particulate-matter
#7
Tianren Wu, Martin Taubel, Rauno Holopainen, Anna-Kaisa Viitanen, Sinikka Vainiotalo, Timo Tuomi, Jorma Keskinen, Anne Hyvärinen, Kaarle Hämeri, Sampo Saari, Brandon Boor
Human-induced resuspension of floor dust is a dynamic process that can serve as a major indoor source of biological particulate matter (bioPM). Inhalation exposure to the microbial content of indoor dust is associated with adverse and protective health effects. This study evaluates infant and adult inhalation exposures and respiratory tract deposited dose rates of resuspended bioPM from carpets. Chamber experiments were conducted with a robotic crawling infant and an adult performing a walking sequence. Breathing zone (BZ) size distributions of resuspended fluorescent biological aerosol particles (FBAPs), a bioPM proxy, were monitored in real-time...
November 16, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/29136418/nano-object-release-during-machining-of-polymer-based-nanocomposites-depends-on-process-factors-and-the-type-of-nanofiller
#8
Yaobo Ding, Wendel Wohlleben, Mael Boland, Klaus Vilsmeier, Michael Riediker
We tested the nanomaterial release from composites during two different mechanical treatment processes, automated drilling and manual sawing. Polyurethane (PU) polymer discs (1-cm thickness and 11-cm diameter) were created using different nanomaterial fillers: multiwall carbon nanotubes (MWCNT), carbon black (CB), silicon dioxide (SiO2), and an unfilled PU control. Drilling generated far more submicron range particles than sawing. In the drilling experiments, none of the tested nanofillers showed a significant influence on particle number concentrations or sizes, except for the PU/MWCNT samples, from which larger particles were released than from control samples...
November 10, 2017: Annals of Work Exposures and Health
https://www.readbyqxmd.com/read/29135231/solid-semi-solid-and-liquid-phase-states-of-individual-submicrometer-particles-directly-probed-using-atomic-force-microscopy
#9
Hansol D Lee, Kamal K Ray, Alexei V Tivanski
Currently, the impact of various phase states of aerosols on the climate is not well understood, especially for submicrometer sized aerosol particles that typically have extended life time in the atmosphere. This is largely due to the inherent size-limitations present in current experimental techniques that aim to directly assess the phase states of fine aerosol particles. Here-in we present a technique that uses atomic force microscopy (AFM) to directly probe for the phase states of individual, submicrometer particles by using nanoindentation and nano-Wilhelmy methodologies as a function of relative humidity (RH) and ambient temperature conditions...
November 14, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/29134986/phase-separation-in-organic-aerosol
#10
Miriam Arak Freedman
Organic aerosol is ubiquitous in the atmosphere, and impacts climate through the scattering and absorption of light and through the formation of nuclei for cloud droplets. These aerosol particles, which are composed of organic compounds and salts, are of great recent interest due to the complex chemistry that occurs within the particles as well as at the air-aerosol interface. Historically, organic aerosol was thought to undergo two phase transitions as the relative humidity around the particles is varied: efflorescence (crystallization) and deliquescence (water uptake)...
November 14, 2017: Chemical Society Reviews
https://www.readbyqxmd.com/read/29132719/a-multidimensional-comparison-between-modis-and-viirs-aod-in-estimating-ground-level-pm2-5-concentrations-over-a-heavily-polluted-region-in-china
#11
Fei Yao, Menglin Si, Weifeng Li, Jiansheng Wu
Satellite-derived aerosol optical depth (AOD) has been proven effective for estimating ground-level particles with an aerodynamic diameter <2.5μm (PM2.5) concentrations. Using a time fixed effects regression model, we compared the capacity of two AOD sources, Moderate Resolution Imaging Spectroradiometer (MODIS) and Visible Infrared Imaging Radiometer Suite (VIIRS), to estimate ground-level PM2.5 concentrations over a heavily polluted region in China. Regarding high-quality AOD data, the results show that the VIIRS model performs better than the MODIS model with respect to all model accuracy evaluation indexes (e...
November 10, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/29131606/first-chemical-characterization-of-refractory-black-carbon-aerosols-and-associated-coatings-over-the-tibetan-plateau-4730-m-a-s-l
#12
Junfeng Wang, Qi Zhang, Min-Dong Chen, Sonya Collier, Shan Zhou, Xinlei Ge, Jianzhong Xu, Jinsen Shi, Conghui Xie, Jianlin Hu, Shun Ge, Yele Sun, Hugh Coe
Refractory black carbon (rBC) aerosol is an important climate forcer, and its impacts are greatly influenced by the species associated with rBC cores. However, relevant knowledge is particularly lacking at the Tibetan Plateau (TP). Here we report, for the first time, highly time-resolved measurement results of rBC and its coating species in central TP (4730 m a.s.l), by using an Aerodyne soot particle aerosol mass spectrometer (SP-AMS), which selectively measured rBC-containing particles. We found that the rBC was overall thickly coated with an average mass ratio of coating to rBC (RBC) of ~7...
November 13, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/29129332/aerosol-deposition-predictions-in-computed-tomography-derived-skeletons-from-severe-asthmatics-a-feasibility-study
#13
REVIEW
Shinjiro Miyawaki, Eric A Hoffman, Sally E Wenzel, Ching-Long Lin
BACKGROUND: The authors numerically investigated the correlation between airway skeletons of severe asthmatic human subjects and predicted aerosol deposition to shed light on the effect of environmental factors on asthma risk. We hypothesized that there are asthmatic subjects whose airway skeletal structure can expose the subject to a risk of higher local aerosol deposition compared to subjects with a more common/normal branching pattern. METHODS: From a population of severe asthmatics studied at total lung capacity via computed tomography we randomly selected 8 subjects whose Forced Expiratory Volume in 1s, percent predicted fell below 45% predicted...
November 4, 2017: Clinical Biomechanics
https://www.readbyqxmd.com/read/29125918/in-vitro-characterization-of-the-eflow-closed-system-nebulizer-with-glycopyrrolate-inhalation-solution
#14
Stephen Pham, Gary T Ferguson, Edward Kerwin, Thomas Goodin, Alistair Wheeler, Andrea Bauer
BACKGROUND: Glycopyrrolate administered by a novel, investigational eFlow(®) Closed System (CS) nebulizer (eFlow CS) is being evaluated for the maintenance treatment of chronic obstructive pulmonary disease (COPD). The eFlow CS is a hand-held, vibrating membrane nebulizer optimized to deliver 1 mL of glycopyrrolate solution into the lung in <3 minutes. Clinical studies have shown improvements in lung function of subjects treated with nebulized glycopyrrolate. METHODS: The aerosol performance of the eFlow CS nebulizer was characterized by delivered dose, aerodynamic droplet size distribution and nebulization time...
November 10, 2017: Journal of Aerosol Medicine and Pulmonary Drug Delivery
https://www.readbyqxmd.com/read/29125064/pulmonary-aerosol-delivery-and-the-importance-of-growth-dynamics
#15
Allen E Haddrell, David Lewis, Tanya Church, Reinhard Vehring, Darragh Murnane, Jonathan P Reid
Aerosols are dynamic systems, responding to variations in the surrounding environmental conditions by changing in size, composition and phase. Although, widely used in inhalation therapies, details of the processes occurring on aerosol generation and during inhalation have received little attention. Instead, research has focused on improvements to the formulation of the drug prior to aerosolization and the resulting clinical efficacy of the treatment. Here, we highlight the processes that occur during aerosol generation and inhalation, affecting aerosol disposition when deposited and, potentially, impacting total and regional doses...
December 2017: Therapeutic Delivery
https://www.readbyqxmd.com/read/29123138/chemical-and-cellular-oxidant-production-induced-by-naphthalene-secondary-organic-aerosol-soa-effect-of-redox-active-metals-and-photochemical-aging
#16
Wing Y Tuet, Yunle Chen, Shierly Fok, Dong Gao, Rodney J Weber, Julie A Champion, Nga L Ng
Exposure to air pollution is a leading global health risk. Secondary organic aerosol (SOA) constitute a large portion of ambient particulate matter (PM). In this study, the water-soluble oxidative potential (OP) determined by dithiothreitol (DTT) consumption and intracellular reactive oxygen and nitrogen species (ROS/RNS) production was measured for SOA generated from the photooxidation of naphthalene in the presence of iron sulfate and ammonium sulfate seed particles. The measured intrinsic OP varied for aerosol formed using different initial naphthalene concentrations, however, no trends were observed between OP and bulk aerosol composition or seed type...
November 9, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29121601/nox-promotion-of-so2-conversion-to-sulfate-an-important-mechanism-for-the-occurrence-of-heavy-haze-during-winter-in-beijing
#17
Jinzhu Ma, Biwu Chu, Jun Liu, Yongchun Liu, Hongxing Zhang, Hong He
In this study, concentrations of NOx, SO2, O3 and fine particles (PM2.5) were measured at three monitoring stations in Beijing during 2015. For extreme haze episodes during 25 Nov. - 3 Dec. 2015, observation data confirmed that high concentrations of NOx promoted the conversion of SO2 to sulfate. Annual data confirmed that this is an important mechanism for the occurrence of heavy haze during winter in Beijing. Furthermore, in situ perturbation experiments in a potential aerosol mass (PAM) reactor were carried out at Shengtaizhongxin (STZX) station during both clean and polluted days...
November 6, 2017: Environmental Pollution
https://www.readbyqxmd.com/read/29120614/connecting-the-elementary-reaction-pathways-of-criegee-intermediates-to-the-chemical-erosion-of-squalene-interfaces-during-ozonolysis
#18
Nadja Heine, Frances A Houle, Kevin R Wilson
Criegee intermediates (CI), formed in alkene ozonolysis, are central for controlling the multiphase chemistry of organic molecules in both indoor and outdoor environments. Here, we examine the heterogeneous ozonolysis of squalene, a key species in indoor air chemistry. Aerosol mass spectrometry is used to investigate how the ozone (O3) concentration, relative humidity (RH), and particle size control reaction rates and mechanisms. Although the reaction rate is found to be independent of RH, the reaction products and particle size depend upon H2O...
November 20, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/29118127/peripheral-blood-biomarkers-of-disease-outcome-in-a-monkey-model-of-rift-valley-fever-encephalitis
#19
Elizabeth R Wonderlich, Amy L Caroline, Cynthia M McMillen, Aaron W Walters, Douglas S Reed, Simon M Barratt-Boyes, Amy L Hartman
Rift Valley Fever (RVF) is an emerging arboviral disease of livestock and people. Although a mosquito-borne virus, humans are infected through contact with or inhalation of virus-laden particles from contaminated animal carcasses. Some individuals infected with RVF virus (RVFV) develop meningoencephalitis resulting in morbidity and mortality. Little is known about the pathogenic mechanisms that lead to neurologic sequelae, and thus animal models that represent human disease are needed. African green monkeys (AGM) exposed to aerosols containing RVFV develop a reproducibly lethal neurological disease that resembles human illness...
November 8, 2017: Journal of Virology
https://www.readbyqxmd.com/read/29113734/cellular-responses-of-human-astrocytoma-cells-to-dust-from-the-acheson-process-an-in-vitro-study
#20
Yke Jildouw Arnoldussen, Torunn Kringlen Ervik, Balazs Berlinger, Ida Kero, Sergey Shaposhnikov, Shanbeh Zienolddiny
Silicon carbide (SiC) is largely used in various products such as diesel particulate filters and solar panels. It is produced through the Acheson process where aerosolized fractions of SiC and other by-products are generated in the work environment and may potentially affect the workers' health. In this study, dust was collected directly on a filter in a furnace hall over a time period of 24h. The collected dust was characterized by scanning electron microscopy and found to contain a high content of graphite particles, and carbon and silicon containing particles...
November 4, 2017: Neurotoxicology
keyword
keyword
121163
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"