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https://www.readbyqxmd.com/read/28723191/highly-enriched-controllable-continuous-aerosol-sampling-using-inertial-microfluidics-and-its-application-to-real-time-detection-of-airborne-bacteria
#1
Jeongan Choi, Seung Chan Hong, Woojin Kim, Jae Hee Jung
We report a novel microfluidic technique for sampling of aerosols into liquids. The two-phase fluid, sampling air and collecting liquid, forms a stratified flow in the curved microchannel. By passing fluids through the curved region, the particles are transferred from air into the liquid phase by the particle centrifugal and drag forces. This microfluidic-based aerosol-into-liquid sampling system, called the MicroSampler, is driven by particle inertial differences. To evaluate the physical particle collection efficiency of the MicroSampler, we used standard polystyrene-latex (PSL) particles ranging in size from 0...
April 28, 2017: ACS Sensors
https://www.readbyqxmd.com/read/28723156/effect-of-drying-rate-on-aerosol-particle-morphology
#2
Muhammad Bilal Altaf, Miriam Arak Freedman
The morphology of aerosol particles impacts their role in the climate system. In the submicron size regime, the morphology of particles that undergo liquid-liquid phase separation is dependent on their size, where for some systems, small particles are homogeneous and large particles are phase separated. We use cryogenic-transmission electron microscopy to probe the morphology of model organic aerosol systems. We observe that the transition region (where both homogeneous and phase separated morphologies are seen) spans 121 nm at the fastest drying rates with a midpoint diameter > 170 nm...
July 19, 2017: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/28720799/reduced-ultrafine-particle-levels-in-s%C3%A3-o-paulo-s-atmosphere-during-shifts-from-gasoline-to-ethanol-use
#3
Alberto Salvo, Joel Brito, Paulo Artaxo, Franz M Geiger
Despite ethanol's penetration into urban transportation, observational evidence quantifying the consequence for the atmospheric particulate burden during actual, not hypothetical, fuel-fleet shifts, has been lacking. Here we analyze aerosol, meteorological, traffic, and consumer behavior data and find, empirically, that ambient number concentrations of 7-100-nm diameter particles rise by one-third during the morning commute when higher ethanol prices induce 2 million drivers in the real-world megacity of São Paulo to substitute to gasoline use (95% confidence intervals: +4,154 to +13,272 cm(-3))...
July 18, 2017: Nature Communications
https://www.readbyqxmd.com/read/28720537/inhaled-powder-formulation-of-naked-sirna-using-spray-drying-technology-with-l-leucine-as-dispersion-enhancer
#4
Michael Y T Chow, Yingshan Qiu, Fiona F K Lo, Hinson H S Lin, Hak-Kim Chan, Philip C L Kwok, Jenny K W Lam
Pulmonary delivery of short interfering RNA (siRNA) has been widely studied in both animal and clinical studies to treat various respiratory diseases by gene silencing through RNA interference. Some of these studies showed that the administration of naked siRNA (without the use of any delivery vectors) could achieve satisfactory gene silencing effect, a unique feature to pulmonary delivery. Liquid aerosols were mostly used with very limited studies on the use of powder aerosols for siRNA. In this study, siRNA was co-spray dried with mannitol and L-leucine, the latter being a dispersion enhancer...
July 15, 2017: International Journal of Pharmaceutics
https://www.readbyqxmd.com/read/28718049/good-things-in-small-packages-an-innovative-delivery-approach-for-inhaled-insulin
#5
James B Fink, Lisa Molloy, John S Patton, Valdecir Castor Galindo-Filho, Jacqueline de Melo Barcelar, Luciana Alcoforado, Simone Cristina Soares Brandão, Armèle Dornelas de Andrade
PURPOSE: The design development of a small, hand held, battery operated, breath actuated inhaler as a drug/device platform for inhaled insulin posed a number of technical challenges. Our goal was to optimize lung deposition and distribution with aerosol generators producing 3-6 μm particle size distribution. METHODS: In silico modeling with computational fluid dynamics (CFD) and in vitro testing of device components were assessed using an Alberta idealized adult airway (Copley, UK) to optimize mouthpiece and aerosol path design for dose delivered distal to the trachea...
July 17, 2017: Pharmaceutical Research
https://www.readbyqxmd.com/read/28711833/assessment-of-nanoparticles-release-into-the-environment-during-drilling-of-carbon-nanotubes-epoxy-and-carbon-nanofibres-epoxy-nanocomposites
#6
Kristof Starost, Evelien Frijns, Jo Van Laer, Nadimul Faisal, Ainhoa Egizabal, Cristina Elizextea, Maria Blazquez, Inge Nelissen, James Njuguna
The risk assessment, exposure and understanding of the release of embedded carbon nanotubes (CNTs) and carbon nanofibers (CNFs) from commercial high performance composites during machining processes are yet to be fully evaluated and quantified. In this study, CNTs and CNFs were dispersed in epoxy matrix through calendaring process to form nanocomposites. The automated drilling was carried out in a specially designed drilling chamber that allowed elimination of background noise from the measurements. Emission measurements were taken using condensed particle counter (CPC), scanning mobility particle sizer (SMPS) and DMS50 Fast Particulate Size Spectrometer...
June 27, 2017: Journal of Hazardous Materials
https://www.readbyqxmd.com/read/28709940/investigation-of-l-leucine-in-reducing-the-moisture-induced-deterioration-of-spray-dried-salbutamol-sulfate-power-for-inhalation
#7
Liang Li, Sharon Shui Yee Leung, Thomas Gengenbach, Jiaqi Yu, Ge Fiona Gao, Patricia Tang, Qi Tony Zhou, Hak-Kim Chan
The aim of this study was to investigate the ability of L-leucine (LL) in preventing moisture-induced deterioration in the in vitro aerosolization performance of spray-dried (SD) salbutamol sulfate (SS). Increasing mass fraction of LL (5-80%) were co-spray dried with SS, and the physicochemical properties of the powders were characterized by laser diffraction, X-ray powder diffraction (XRD) and dynamic vapour sorption (DVS). Furthermore, the surface morphology and chemistry of fine particles was analyzed by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS)...
July 11, 2017: International Journal of Pharmaceutics
https://www.readbyqxmd.com/read/28709369/deposition-and-light-absorption-characteristics-of-precipitation-dissolved-organic-carbon-doc-at-three-remote-stations-in-the-himalayas-and-tibetan-plateau-china
#8
Chaoliu Li, Fangping Yan, Shichang Kang, Pengfei Chen, Zhaofu Hu, Xiaowen Han, Guoshuai Zhang, Shaopeng Gao, Bin Qu, Mika Sillanpää
The concentrations, depositions and optical properties of precipitation DOC at three remote stations (Nam Co, Lulang and Everest) were investigated in the Himalayas and Tibetan Plateau (HTP). The results showed that their volume-weighted mean DOC concentrations were 1.05±1.01mgCL(-1), 0.83±0.85mgCL(-1) and 0.86±0.91mgCL(-1), respectively, close to those of other remote areas in the world and lower than those of typical polluted urban cities. Combined with precipitation amounts, the DOC depositions at these three stations were calculated to be 0...
July 10, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28707900/aerosol-fragmentation-driven-by-coupling-of-acid-base-and-free-radical-chemistry-in-the-heterogeneous-oxidation-of-aqueous-citric-acid-by-oh-radicals
#9
Matthew J Liu, Aaron A Wiegel, Kevin R Wilson, Frances A Houle
A key uncertainty in the heterogeneous oxidation of carboxylic acids by hydroxyl radicals (OH) in aqueous phase aerosol is how the free radical reaction pathways might be altered by acid-base chemistry. In particular, if acid-base reactions occur concurrently with acyloxy radical formation and unimolecular decomposition of alkoxy radicals, there is a possibility that differences in reaction pathways impact the partitioning of organic carbon between the gas and aqueous phases. To examine these questions, a kinetic model is developed for the OH initiated oxidation of citric acid aerosol at high relative humidity...
July 14, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28706240/gasoline-cars-produce-more-carbonaceous-particulate-matter-than-modern-filter-equipped-diesel-cars
#10
S M Platt, I El Haddad, S M Pieber, A A Zardini, R Suarez-Bertoa, M Clairotte, K R Daellenbach, R-J Huang, J G Slowik, S Hellebust, B Temime-Roussel, N Marchand, J de Gouw, J L Jimenez, P L Hayes, A L Robinson, U Baltensperger, C Astorga, A S H Prévôt
Carbonaceous particulate matter (PM), comprising black carbon (BC), primary organic aerosol (POA) and secondary organic aerosol (SOA, from atmospheric aging of precursors), is a highly toxic vehicle exhaust component. Therefore, understanding vehicle pollution requires knowledge of both primary emissions, and how these emissions age in the atmosphere. We provide a systematic examination of carbonaceous PM emissions and parameterisation of SOA formation from modern diesel and gasoline cars at different temperatures (22, -7 °C) during controlled laboratory experiments...
July 13, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28700243/impact-of-wildfire-emissions-on-chloride-and-bromide-depletion-in-marine-aerosol-particles
#11
Rachel Anne Braun, Hossein Dadashazar, Alexander B MacDonald, Abdulamonam M Aldhaif, Lindsay C Maudlin, Ewan Crosbie, Mojtaba Azadi Aghdam, Ali Hossein Mardi, Armin Sorooshian
This work examines particulate chloride (Cl(-)) and bromide (Br(-)) depletion in marine aerosol particles influenced by wildfires at a coastal California site in the summers of 2013 and 2016. Chloride exhibited a dominant coarse mode due to sea salt influence, with substantially diminished concentrations during fire periods as compared to non-fire periods. Bromide exhibited a peak in the submicrometer range during fire and non-fire periods, with an additional supermicrometer peak in the latter periods. Chloride and Br(-) depletions were enhanced during fire periods as compared to non-fire periods...
July 12, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28700203/mechanisms-of-atmospherically-relevant-cluster-growth
#12
Bryan R Bzdek, Joseph W DePalma, Murray V Johnston
Atmospheric aerosols impact global climate either directly by scattering solar radiation or indirectly by serving as cloud condensation nuclei, which influence cloud albedo and precipitation patterns. Our scientific understanding of these impacts is poor relative to that of, for instance, greenhouse gases, in part because it is difficult to predict particle number concentrations. One important pathway by which particles are added to the atmosphere is new particle formation, where gas phase precursors form molecular clusters that subsequently grow to the climatically relevant size range (50-100 nm diameter)...
July 12, 2017: Accounts of Chemical Research
https://www.readbyqxmd.com/read/28699827/evaluation-of-a-passive-method-for-determining-particle-penetration-through-protective-clothing-materials
#13
Peter A Jaques, Lee Portnoff
The risk of workers' exposure to aerosolized particles has increased with the upsurge in the production of engineered nanomaterials. Currently, a whole-body standard test method for measuring particle penetration through protective clothing ensembles is not available. Those available for respirators neglect the most common challenges to ensembles, because they use active vacuum-based filtration, designed to simulate breathing, rather than the positive forces of wind experienced by workers. Thus, a passive method that measures wind-driven particle penetration through ensemble fabric has been developed and evaluated...
July 12, 2017: Journal of Occupational and Environmental Hygiene
https://www.readbyqxmd.com/read/28697387/influence-of-continental-organic-aerosols-to-the-marine-atmosphere-over-the-east-china-sea-insights-from-lipids-pahs-and-phthalates
#14
Mingjie Kang, Fan Yang, Hong Ren, Wanyu Zhao, Ye Zhao, Linjie Li, Yu Yan, Yingjie Zhang, Senchao Lai, Yingyi Zhang, Yang Yang, Zifa Wang, Yele Sun, Pingqing Fu
Total suspended particle (TSP) samples were collected during a marine cruise in the East China Sea from May 18 to June 12, 2014. They were analyzed for solvent extractable organic compounds (lipid compounds, PAHs and phthalates) using gas chromatography/mass spectrometry (GC/MS) to better understand the sources and source apportionment of aerosol pollution in the western North Pacific. Higher concentrations were observed in the terrestrially influenced aerosol samples on the basis of five-day backward air mass trajectories, especially for aerosols collected near coastal areas...
July 8, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28696102/release-and-gas-particle-partitioning-behaviors-of-short-chain-chlorinated-paraffins-sccps-during-the-thermal-treatment-of-polyvinyl-chloride-flooring
#15
Faqiang Zhan, Haijun Zhang, Jing Wang, Jiazhi Xu, Heping Yuan, Yuan Gao, Fan Su, Jiping Chen
Chlorinated paraffin (CP) mixture is a common additive in polyvinyl chloride (PVC) products as a plasticizer and flame retardant. During the PVC plastic life cycle, intentional or incidental thermal processes inevitably cause an abrupt release of short-chain CPs (SCCPs). In this study, the thermal processing of PVC plastics was simulated by heating PVC flooring at 100-200 °C in a chamber. The 1-h thermal treatment caused the release of 1.9%-10.7% of the embedded SCCPs. A developed emission model indicated that SCCP release was mainly controlled by material-gas partitioning at 100 °C...
July 11, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28692913/particle-and-bioaerosol-characteristics-in-a-paediatric-intensive-care-unit
#16
Congrong He, Ian M Mackay, Kay Ramsay, Zhen Liang, Timothy Kidd, Luke D Knibbs, Graham Johnson, Donna McNeale, Rebecca Stockwell, Mark G Coulthard, Debbie A Long, Tara J Williams, Caroline Duchaine, Natalie Smith, Claire Wainwright, Lidia Morawska
The paediatric intensive care unit (PICU) provides care to critically ill neonates, infants and children. These patients are vulnerable and susceptible to the environment surrounding them, yet there is little information available on indoor air quality and factors affecting it within a PICU. To address this gap in knowledge we conducted continuous indoor and outdoor airborne particle concentration measurements over a two-week period at the Royal Children's Hospital PICU in Brisbane, Australia, and we also collected 82 bioaerosol samples to test for the presence of bacterial and viral pathogens...
July 7, 2017: Environment International
https://www.readbyqxmd.com/read/28691810/measurements-of-the-imaginary-component-of-the-refractive-index-of-weakly-absorbing-single-aerosol-particles
#17
Rose E Willoughby, Michael I Cotterell, Hongze Lin, Andrew J Orr-Ewing, Jonathan Philip Reid
The interaction of atmospheric aerosols with radiation remains a significant source of uncertainty in modelling radiative forcing. Laboratory measurements of the microphysical properties of atmospherically relevant particles is one approach to reduce this uncertainty. We report a new method to investigate light absorption by a single aerosol particle, inferring changes in the imaginary part of the refractive index with change in environmental conditions (e.g. relative humidity) and inferring the size dependence of the optical extinction cross-section...
July 10, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28691807/spectroscopic-determination-of-aerosol-ph-from-acid-base-equilibria-in-inorganic-organic-and-mixed-systems
#18
Rebecca Lynn Craig, Lucy Nandy, Jessica Lynne Axson, Cari S Dutcher, Andrew P Ault
Atmospheric aerosol acidity impacts key multiphase processes, such as acid-catalyzed reactions leading to secondary organic aerosol formation, which impact climate and human health. However, traditional indirect methods of estimating aerosol pH often disagree with thermodynamic model predictions, resulting in aerosol acidity still being poorly understood in the atmosphere. Herein, a recently developed method coupling Raman microspectroscopy with extended Debye-Hückel activity calculations to directly determine the acidity of individual particles was applied to a range of atmospherically-relevant inorganic and organic acid-base equilibria systems (HNO3/NO3-, HC2O4-/C2O42-, CH3COOH/CH3COO-, and HCO3-/CO32-) covering a broad pH range (-1 to 10), as well as an inorganic-organic mixture (sulfate-oxalate)...
July 10, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28690715/a-novel-aerodynamic-sizing-method-for-pharmaceutical-aerosols-using-image-based-analysis-of-settling-velocities
#19
Rami Fishler, Josué Sznitman
This article discusses a novel method to estimate aerodynamic particle size distributions (APSDs) of pharmaceutical aerosols through direct measurement of particle settling velocities using image-based analysis and particle tracking techniques. This simple, optical method provides accurate and fast measurements (approximately 1 minute) with few sources of bias due to specific device design choices or operation conditions. A proof-of-concept for the method is demonstrated by measuring APSDs for widely available commercial dry powder inhalers (DPIs), then comparing the results with previously published data from cascade impactors (CIs) and the Aerodynamic Particle Sizer (APS)...
June 2017: Inhalation
https://www.readbyqxmd.com/read/28689407/direct-on-line-determination-of-laser-induced-particle-size-distribution-by-icpms
#20
Ariane Donard, Fanny Claverie, Fabien Pointurier, Céline Blitz Frayret, Barbora Svatosova, Christophe Pecheyran
The characterization of the aerosol (size, composition and concentration) generated by Laser Ablation is of great interest due to its impact on the analytical performances when coupled to Inductively Coupled Plasma Mass Spectrometry (ICPMS). The capabilities of High Resolution ICPMS as a direct tool to characterize nanoparticles produced by femtosecond Laser Ablation of pure copper are presented. An analytical protocol, similar to the 'single particle ICPMS' technique used to characterize the size distribution of nanoparticles in solution, was developed in order to observe the signals of individual particles produced by a single ablation shot...
July 8, 2017: Analytical Chemistry
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