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Ultrafine particles

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https://www.readbyqxmd.com/read/28925870/pollution-and-sun-exposure-a-deleterious-synergy-mechanisms-and-opportunities-for-skin-protection
#1
Laurent Marrot
Pollutants are highly diverse chemical entities, including gases such as ozone or nitrogen and sulphur oxides and particulate matter of different sizes and with different chemical constituents. PM2.5 is composed of particles that are sometimes about ten nanometres or so in size (ultrafine particles) which can be deposited in lung alveoli, translocated into capillaries and then distributed to all organs through blood circulation. PM2.5 is often associated with toxic chemicals such as heavy metals or polycyclic aromatic hydrocarbons (PAHs) and some photo-reactive PAHs can induce strong oxidative stress under UVA exposure...
September 18, 2017: Current Medicinal Chemistry
https://www.readbyqxmd.com/read/28916396/ultrafine-particle-transport-and-deposition-in-a-large-scale-17-generation-lung-model
#2
Mohammad S Islam, Suvash C Saha, Emilie Sauret, Tevfik Gemci, Ian A Yang, Y T Gu
To understand how to assess optimally the risks of inhaled particles on respiratory health, it is necessary to comprehend the uptake of ultrafine particulate matter by inhalation during the complex transport process through a non-dichotomously bifurcating network of conduit airways. It is evident that the highly toxic ultrafine particles damage the respiratory epithelium in the terminal bronchioles. The wide range of in silico available and the limited realistic model for the extrathoracic region of the lung have improved understanding of the ultrafine particle transport and deposition (TD) in the upper airways...
September 5, 2017: Journal of Biomechanics
https://www.readbyqxmd.com/read/28916281/explaining-the-spatiotemporal-variation-of-fine-particle-number-concentrations-over-beijing-and-surrounding-areas-in-an-air-quality-model-with-aerosol-microphysics
#3
Xueshun Chen, Zifa Wang, Jie Li, Huansheng Chen, Min Hu, Wenyi Yang, Zhe Wang, Baozhu Ge, Dawei Wang
In this study, a three-dimensional air quality model with detailed aerosol microphysics (NAQPMS + APM) was applied to simulate the fine particle number size distribution and to explain the spatiotemporal variation of fine particle number concentrations in different size ranges over Beijing and surrounding areas in the haze season (Jan 15 to Feb 13 in 2006). Comparison between observations and the simulation indicates that the model is able to reproduce the main features of the particle number size distribution...
September 12, 2017: Environmental Pollution
https://www.readbyqxmd.com/read/28916279/the-role-of-il-6-released-from-pulmonary-epithelial-cells-in-diesel-ufp-induced-endothelial-activation
#4
Rossella Bengalli, Eleonora Longhin, Sara Marchetti, Maria C Proverbio, Cristina Battaglia, Marina Camatini
Diesel exhaust particles (DEP) and their ultrafine fraction (UFP) are known to induce cardiovascular effects in exposed subjects. The mechanisms leading to these outcomes are still under investigation, but the activation of respiratory endothelium is likely to be involved. Particles translocation through the air-blood barrier and the release of mediators from the exposed epithelium have been suggested to participate in the process. Here we used a conditioned media in vitro model to investigate the role of epithelial-released mediators in the endothelial cells activation...
September 12, 2017: Environmental Pollution
https://www.readbyqxmd.com/read/28914166/repeated-iron-soot-exposure-and-nose-to-brain-transport-of-inhaled-ultrafine-particles
#5
Laurie E Hopkins, Emilia A Laing, Janice L Peake, Dale Uyeminami, Savannah M Mack, Xueting Li, Suzette Smiley-Jewell, Kent E Pinkerton
Particulate exposure has been implicated in the development of a number of neurological maladies such as multiple sclerosis, amyotrophic lateral sclerosis, Alzheimer's disease, and idiopathic Parkinson's disease. Only a few studies have focused on the olfactory pathway as a portal through which combustion-generated particles may enter the brain. The primary objective of this study was to define the deposition, uptake, and transport of inhaled ultrafine iron-soot particles in the nasal cavities of mice to determine whether combustion-generated nanoparticles reach the olfactory bulb via the olfactory epithelium and nerve fascicles...
January 1, 2017: Toxicologic Pathology
https://www.readbyqxmd.com/read/28889028/development-and-in-vitro-in-vivo-performance-of-self-nanoemulsifying-drug-delivery-systems-loaded-with-candesartan-cilexetil
#6
Khaled AboulFotouh, Ayat A Allam, Mahmoud El-Badry, Ahmed M El-Sayed
Candesartan cilexetil is widely used in the management of hypertension and heart failure. The drug delivery encounters obstacles of poor aqueous solubility, efflux by intestinal P-glycoprotein and vulnerability to enzymatic degradation in small intestine. Self-nanoemulsifying drug delivery systems (SNEDDS) loaded with candesartan cilexetil were successfully developed to overcome such obstacles. Preliminary screening was carried out to select proper surfactant, co-surfactant and oil combination for successful SNEDDS formulation...
September 6, 2017: European Journal of Pharmaceutical Sciences
https://www.readbyqxmd.com/read/28882703/pegylation-for-enhancing-nanoparticle-diffusion-in-mucus
#7
Justin T Huckaby, Samuel K Lai
The viscoelastic mucus secretions coating exposed organs such as the lung airways and the female reproductive tract can trap and quickly eliminate not only foreign pathogens and ultrafine particles but also particle-based drug delivery systems, thus limiting sustained and targeted drug delivery at mucosal surfaces. To improve particle distribution across the mucosa and enhance delivery to the underlying epithelium, many investigators have sought to develop nanoparticles capable of readily traversing mucus. The first synthetic nanoparticles shown capable of rapidly penetrating physiological mucus secretions utilized a dense coating of polyethylene glycol (PEG) covalently grafted onto the surface of preformed polymeric nanoparticles...
September 4, 2017: Advanced Drug Delivery Reviews
https://www.readbyqxmd.com/read/28871170/capturing-pm2-5-emissions-from-3d-printing-via-nanofiber-based-air-filter
#8
Chengchen Rao, Fu Gu, Peng Zhao, Nusrat Sharmin, Haibing Gu, Jianzhong Fu
This study investigated the feasibility of using polycaprolactone (PCL) nanofiber-based air filters to capture PM2.5 particles emitted from fused deposition modeling (FDM) 3D printing. Generation and aggregation of emitted particles were investigated under different testing environments. The results show that: (1) the PCL nanofiber membranes are capable of capturing particle emissions from 3D printing, (2) relative humidity plays a signification role in aggregation of the captured particles, (3) generation and aggregation of particles from 3D printing can be divided into four stages: the PM2...
September 4, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28866382/robustness-of-intra-urban-land-use-regression-models-for-ultrafine-particles-and-black-carbon-based-on-mobile-monitoring
#9
Jules Kerckhoffs, Gerard Hoek, Jelle Vlaanderen, Erik van Nunen, Kyle Messier, Bert Brunekreef, John Gulliver, Roel Vermeulen
Land-use regression (LUR) models for ultrafine particles (UFP) and Black Carbon (BC) in urban areas have been developed using short-term stationary monitoring or mobile platforms in order to capture the high variability of these pollutants. However, little is known about the comparability of predictions of mobile and short-term stationary models and especially the validity of these models for assessing residential exposures and the robustness of model predictions developed in different campaigns. We used an electric car to collect mobile measurements (n = 5236 unique road segments) and short-term stationary measurements (3 × 30min, n = 240) of UFP and BC in three Dutch cities (Amsterdam, Utrecht, Maastricht) in 2014-2015...
August 31, 2017: Environmental Research
https://www.readbyqxmd.com/read/28865356/chemical-composition-of-submicron-and-fine-particulate-matter-collected-in-krakow-poland-consequences-for-the-aparic-project
#10
Lucyna Samek, Leszek Furman, Magdalena Mikrut, Anna Regiel-Futyra, Wojciech Macyk, Grażyna Stochel, Rudi van Eldik
Submicron particulate matter containing particles with an aerodynamic diameter ≤1 μm (PM1) are not monitored continuously by Environmental Protection Agencies around the World and are seldom studied. Numerous studies have indicated that people exposed to ultrafine (≤100 nm), submicron and fine particulate matter containing particles with an aerodynamic diameter ≤2.5 μm (PM2.5), can suffer from respiratory track diseases, cardiovascular, immunological or heart diseases and others. Inorganic pollutants containing redox active transition metals and small gaseous molecules, are involved in the generation of reactive oxygen and reactive nitrogen species...
August 30, 2017: Chemosphere
https://www.readbyqxmd.com/read/28858754/longitudinal-association-between-air-pollution-exposure-at-school-and-cognitive-development-in-school-children-over-a-period-of-3-5-years
#11
Joan Forns, Payam Dadvand, Mikel Esnaola, Mar Alvarez-Pedrerol, Mònica López-Vicente, Raquel Garcia-Esteban, Marta Cirach, Xavier Basagaña, Mònica Guxens, Jordi Sunyer
INTRODUCTION: Recently, we showed that exposure to traffic-related air pollutants (TRAPs) at school was negatively associated with cognitive development, specifically working memory and inattentiveness, in primary schoolchildren during a course of 12 months. The persistence of such associations over longer periods remains as an open question. OBJECTIVE: To study the longitudinal association between TRAPs at school and cognitive development over a period of 3.5 years...
September 1, 2017: Environmental Research
https://www.readbyqxmd.com/read/28841501/analysis-of-polycyclic-aromatic-hydrocarbons-pahs-in-air-using-passive-sampling-calibrated-with-active-measurements
#12
K M Ellickson, C M McMahon, C Herbrandson, M J Krause, C M Schmitt, C J Lippert, G C Pratt
There are limited ambient air measurements of extended (beyond EPA Priority 16) lists of polycyclic aromatic hydrocarbons (PAHs). We measured air concentrations of 45 PAHs using passive and active air sampling at 15 sites in a central urban community and one rural site for two years. Passive sampling was conducted with cylindrical XAD-based samplers deployed to capture spatial variability. High volume active samplers with quartz fiber filters for particles and XAD-4 absorbent for gases were deployed at two urban sites and the rural site to calibrate the passive measurements directly...
August 22, 2017: Environmental Pollution
https://www.readbyqxmd.com/read/28841286/high-rate-long-life-pored-nanoribbon-vnb9o25-built-by-interconnected-ultrafine-nanoparticles-as-anode-for-lithium-ion-batteries
#13
Shangshu Qian, Haoxiang Yu, Lei Yan, Haojie Zhu, Xing Cheng, Ying Xie, Nengbing Long, Miao Shui, Jie Shu
VNb9O25 is a novel lithium storage material, which has not been systematically investigated so far. Via electrospinning technology, VNb9O25 samples with two different morphologies, pored nanoribbon and rodlike nanoparticles, are prepared in relatively low temperature and time-saving calcination conditions. It is found that the formation process of different morphologies depends on the control of self-aggregation of the precursor by using different sample collectors. Compared with rodlike VNb9O25 (RL-VNb9O25), pored nanoribbon VNb9O25 (PR-VNb9O25) can deliver a higher specific capacity, lower capacity loss, and better cyclability...
September 13, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28825871/resistance-of-type-5-chemical-protective-clothing-against-nanometric-airborne-particles-behaviour-of-seams-and-zipper
#14
Ludwig Vinches, Stéphane Hallé
In the field of dermal protection, the use of chemical protective clothing (CPC) (including coveralls) are considered as the last barrier against airborne engineered nanomaterials (ENM). In the majority of cases, type 5 CPC, used against solid particles (ISO 13982-1), perform well against ENM. But in a recent study, a penetration level (PL) of up to 8.5% of polydisperse sodium chloride airborne nanoparticles has been measured. Moreover, in all the previous studies, tests were performed on a sample of protective clothing material without seams or zippers...
August 21, 2017: Journal of Occupational and Environmental Hygiene
https://www.readbyqxmd.com/read/28819141/constructing-the-novel-ultrafine-amorphous-iron-oxyhydroxide-g-c3n4-nanosheets-heterojunctions-for-highly-improved-photocatalytic-performance
#15
Hongcen Yang, Shouwei Zhang, Ruya Cao, Xiaolong Deng, Zhipeng Li, Xijin Xu
Ultrafine particles, more heterojunction interfaces and amorphous materials can effectively enhance the photocatalytic activity of photocatalysts. In this work, a facile in-situ precipitation method was developed to prepare ultrafine amorphous iron oxyhydroxide/ultrathin g-C3N4 nanosheets heterojunction composites. The amorphous iron oxyhydroxide possessed an ultrafine particle size and a wide range of visible light absorption. In this process, the ultrafine particles not only shortened the diffusion distance of photogenerated carriers, but also facilitated the formation of more heterojunctions with ultrathin g-C3N4 nanosheets...
August 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28818812/airborne-ultrafine-particles-in-a-pacific-island-country-characteristics-sources-and-implications-for-human-exposure
#16
C F Isley, P F Nelson, M P Taylor, M Mazaheri, L Morawska, A J Atanacio, E Stelcer, D D Cohen, Anthony L Morrison
The Pacific Islands carry a perception of having clean air, yet emissions from transport and burning activities are of concern in regard to air quality and health. Ultrafine particle number concentrations (PNCs), one of the best metrics to demonstrate combustion emissions, have not been measured either in Suva or elsewhere in the Islands. This work provides insight into PNC variation across Suva and its relationship with particle mass (PM) concentration and composition. Measurements over a short monitoring campaign provide a vignette of conditions in Suva...
August 14, 2017: Environmental Pollution
https://www.readbyqxmd.com/read/28813539/vectorization-by-nanoparticles-decreases-the-overall-toxicity-of-airborne-pollutants
#17
Rodolphe Carpentier, Anne Platel, Helena Maiz-Gregores, Fabrice Nesslany, Didier Betbeder
Atmospheric pollution is mainly composed of volatile pollutants and particulate matter that strongly interact. However, their specific roles in the induction of cellular toxicity, in particular the impact of the vectorization of atmospheric pollutants by ultrafine particles, remains to be fully elucidated. For this purpose, non-toxic poly-lactic co-glycolic acid (PLGA) nanoparticles were synthesized and three pollutants (benzo(a)pyrene, naphthalene and di-ethyl-hexyl-phthalate) were adsorbed on the surface of the nanoparticles in order to evaluate the toxicity (cytotoxicity, genotoxicity and ROS induction) of these complexes to a human airway epithelial cell line...
2017: PloS One
https://www.readbyqxmd.com/read/28810687/the-characterization-of-polycyclic-aromatic-hydrocarbons-in-northeastern-us-trucking-terminals
#18
Erica D Walker, Jaime E Hart, Eric Garshick, Jennifer M Cavallari, Mary E Davis, Thomas J Smith, Francine Laden
In recent years, significant attention has been given to polycyclic aromatic hydrocarbons (PAHs) exposures given their mutagenic and carcinogenic properties. However, levels of exposure and the key determinants of exposure are not well defined for the trucking industry. We measured ultrafine particle characteristics at 10 trucking terminals of varying operating size and location in the Northeast region of the United States using particle concentration counter and a surface area analyzer. Multivariate mixed-effects linear regression models were used to assess determinants of the concentration of total bound PAHs (tPAH), the total aerosol active surface area (AS), and the ratio tPAH/AS overall and individually within docks, trucking cabs, and administrative offices...
August 1, 2017: Annals of Work Exposures and Health
https://www.readbyqxmd.com/read/28810681/workplace-measurements-of-ultrafine-particles-a-literature-review
#19
Anna-Kaisa Viitanen, Sanni Uuksulainen, Antti J Koivisto, Kaarle Hämeri, Timo Kauppinen
Workers are exposed to ultrafine particles (UFP) in a number of occupations. In order to summarize the current knowledge regarding occupational exposure to UFP (excluding engineered nanoparticles), we gathered information on UFP concentrations from published research articles. The aim of our study was to create a basis for future epidemiological studies that treat UFP as an exposure factor. The literature search found 72 publications regarding UFP measurements in work environments. These articles covered 314 measurement results and tabled concentrations...
August 1, 2017: Annals of Work Exposures and Health
https://www.readbyqxmd.com/read/28773075/magnetic-hysteresis-in-nanocomposite-films-consisting-of-a-ferromagnetic-auco-alloy-and-ultrafine-co-particles
#20
Federico Chinni, Federico Spizzo, Federico Montoncello, Valentina Mattarello, Chiara Maurizio, Giovanni Mattei, Lucia Del Bianco
One fundamental requirement in the search for novel magnetic materials is the possibility of predicting and controlling their magnetic anisotropy and hence the overall hysteretic behavior. We have studied the magnetism of Au:Co films (~30 nm thick) with concentration ratios of 2:1, 1:1, and 1:2, grown by magnetron sputtering co-deposition on natively oxidized Si substrates. They consist of a AuCo ferromagnetic alloy in which segregated ultrafine Co particles are dispersed (the fractions of Co in the AuCo alloy and of segregated Co increase with decreasing the Au:Co ratio)...
June 28, 2017: Materials
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