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https://www.readbyqxmd.com/read/28930472/light-absorption-of-secondary-organic-aerosol-composition-and-contribution-of-nitro-aromatic-compounds
#1
Mingjie Xie, Xi Chen, Michael D Hays, Michael Lewandowski, John H Offenberg, Tadeusz Edward Kleindienst, Amara Holder
Secondary organic aerosol (SOA) might affect the atmospheric radiation balance through absorbing light at shorter visible and UV wavelengths. However, the composition and optical properties of light-absorbing SOA is poorly understood. In this work, SOA filter samples were collected during individual chamber experiments with three biogenic and eight aromatic volatile organic compound (VOC) precursors in the presence of NOX and H2O2. Compared with the SOA generated using the aromatic precursors, biogenic SOA in general exhibits negligible light absorption above 350 nm; the aromatic SOA generated in the presence of NOX showed stronger light absorption than that generated with H2O2...
September 20, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28929752/speciation-and-sources-of-brown-carbon-in-precipitation-at-seoul-korea-insights-from-excitation-emission-matrix-spectroscopy-and-carbon-isotopic-analysis
#2
Ge Yan, Guebuem Kim
Brown carbon (BrC) plays a significant role in the Earth's radiative balance, yet its sources and chemical composition remain poorly understood. In this work, we investigated BrC in the atmospheric environment of Seoul by characterizing dissolved organic matter in precipitation using excitation-emission matrix (EEM) fluorescence spectroscopy coupled with parallel factor analysis (PARAFAC). The two independent fluorescent components identified by PARAFAC were attributed to humic-like substance (HULIS) and biologically-derived material based on their significant correlations with measured HULIS isolated using solid-phase extraction and total hydrolyzable tyrosine...
September 20, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28923742/effects-of-calcination-temperature-and-heating-rate-on-the-photocatalytic-properties-of-zno-prepared-by-pyrolysis
#3
Lingling He, Zhifang Tong, Zhonghua Wang, Ming Chen, Ni Huang, Wei Zhang
A series of ZnO nanorods were prepared by pyrolysis of zinc acetate at different calcination temperatures and heating rates under ambient atmosphere. The as-prepared ZnO nanorods were characterized by X-ray diffractometer (XRD), scanning electron microscopy (SEM), UV-visible diffuse reflectance spectroscopy (DRS) and X-ray photoelectron spectroscopy (XPS). The photocatalytic performances of the ZnO nanorods were evaluated by the photodegradation of methyl orange (MO) and 4-nitrophenol (4-NP). The morphology, optical property, surface composition, and photocatalytic performance of the ZnO samples were affected by both calcination temperature and heating rate...
September 8, 2017: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/28922714/atmospheric-levels-and-cytotoxicity-of-polycyclic-aromatic-hydrocarbons-and-oxygenated-pahs-in-pm2-5-in-the-beijing-tianjin-hebei-region
#4
Xinyi Niu, Steven Sai Hang Ho, Kin Fai Ho, Yu Huang, Jian Sun, Qiyuan Wang, Yaqing Zhou, Zhuzi Zhao, Junji Cao
The chemical composition of PM2.5 and cellular effects from exposure to fine aerosol extracts were studied for samples collected in Beijing, Tianjin, Shijiazhuang, and Hengshui, China in winter 2015. Effects of priority polycyclic aromatic hydrocarbons (PAHs) and their oxygenated derivatives (OPAHs) in PM2.5 on cell cultures were a major focus of the study. Total quantified PAHs and OPAHs at Shijiazhuang and Hengshui were higher than at Beijing and Tianjin, and benz(a)anthracene, chrysene and 1,8-naphthalic anhydride were the most abundant species...
September 12, 2017: Environmental Pollution
https://www.readbyqxmd.com/read/28920759/spatial-distribution-of-polycyclic-aromatic-hydrocarbon-and-polychlorinated-biphenyl-sources-in-the-nakdong-river-estuary-south-korea
#5
Jun H Lee, Han J Woo, Kap S Jeong, Jeong W Kang, Jae U Choi, Eun J Jeong, Kap S Park, Dong H Lee
Our research team investigated the elemental composition and the presence of various toxic organic compounds, such as polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs), in estuary surface sediments to trace the spatial distribution of the sources of pollution deposited in Nakdong River, Busan, South Korea. The spatial patterns of elemental composition and toxic organic compounds were determined from the measurements of total organic carbon (TOC), total nitrogen, total sulfur, PAHs, and PCBs...
September 18, 2017: Journal of Environmental Science and Health. Part A, Toxic/hazardous Substances & Environmental Engineering
https://www.readbyqxmd.com/read/28920627/site-preferences-in-hetero-metallic-fe9-xnix-clusters-a-combined-crystallographic-spectroscopic-and-theoretical-analysis
#6
Anastasia N Georgopoulou, Karrar Al-Ameed, Athanassios K Boudalis, Dimitrios F Anagnostopoulos, Vassilis Psycharis, John E McGrady, Yiannis Sanakis, Catherine P Raptopoulou
The reaction of mixtures of Fe(O2CMe)2·2H2O and Ni(O2CMe)2·4H2O of various compositions with di-2-pyridyl ketone (py2CO, dpk) in MeCN under an inert atmosphere afforded a family of hetero-metallic enneanuclear clusters with general formula [Fe9-xNix(μ4-OH)2(O2CMe)8(py2CO2)4] (2, x = 1.00; 3: x = 6.02; 4, x = 7.46; 5, x = 7.81). Clusters 2-5 are isomorphous to the homo-metallic [Fe9] cluster (1) previously reported by some of us, and also isostructural to the known homo-metallic [Ni9] cluster. All four clusters contain a central M(II) ion in an unusual 8-coordinate site and eight peripheral M(II) ions in distorted octahedral environments...
September 18, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28919900/preliminary-studies-to-characterize-the-temporal-variation-of-micronutrient-composition-of-the-above-ground-organs-of-maize-and-correlated-uptake-rates
#7
Karla Vilaça Martins, Durval Dourado-Neto, Klaus Reichardt, Quirijn de Jong van Lier, José Laércio Favarin, Felipe Fadel Sartori, Guilherme Felisberto, Simone da Costa Mello
The improvement of agronomic practices and the use of high technology in field crops contributes for significant increases in maize productivity, and may have altered the dynamics of nutrient uptake and partition by the plant. Official recommendations for fertilizer applications to the maize crop in Brazil and in many countries are based on critical soil nutrient contents and are relatively outdated. Since the factors that interact in an agricultural production system are dynamic, mathematical modeling of the growth process turns out to be an appropriate tool for these studies...
2017: Frontiers in Plant Science
https://www.readbyqxmd.com/read/28915541/temporal-variability-in-aerosol-characteristics-and-its-radiative-properties-over-patiala-northwestern-part-of-india-impact-of-agricultural-biomass-burning-emissions
#8
D Sharma, A K Srivastava, K Ram, A Singh, D Singh
A comprehensive measurements of aerosol optical depth (AOD), particulate matter (PM) and black carbon (BC) mass concentrations have been carried out over Patiala, a semi-urban site in northwest India during October 2008 to September 2010. The measured aerosol data was incorporated in an aerosol optical model to estimate various aerosol optical parameters, which were subsequently used for radiative forcing estimation. The measured AOD at 500 nm (AOD500) shows a significant seasonal variability, with maximum value of 0...
September 11, 2017: Environmental Pollution
https://www.readbyqxmd.com/read/28915375/the-presence-of-mercury-and-other-trace-metals-in-surface-soils-in-the-norwegian-arctic
#9
Katharina Halbach, Øyvind Mikkelsen, Torunn Berg, Eiliv Steinnes
Svalbard is an important study area for investigating the long-range transport of mercury (Hg) and other trace elements to the Arctic. Few studies have focused on their concentrations in Arctic soils. With ongoing climate change leading to thawing permafrost ground the soil compartment is of increasing importance in the Arctic. In this study, elemental composition and soil organic matter (SOM) content of surface and mineral soils in Svalbard are presented. The aim is to provide new data on soils in the Arctic and to gain more knowledge about the role of the soil in the biogeochemical cycle of mercury (Hg)...
September 7, 2017: Chemosphere
https://www.readbyqxmd.com/read/28910093/uptake-of-gaseous-alkylamides-by-suspended-sulfuric-acid-particles-formation-of-ammonium-aminium-salts
#10
Hangfei Chen, MingYi Wang, Lei Yao, Jianmin Chen, Lin Wang
Amides represent an important class of nitrogen-containing compounds in the atmosphere that can in theory interact with atmospheric acidic particles and contribute to secondary aerosol formation. In this study, uptake coefficients (γ) of six alkylamides (C1 to C3) by suspended sulfuric acid particles were measured using an aerosol flow tube coupled to a High Resolution Time-of-Flight Chemical Ionization Mass Spectrometer (HRToF-CIMS). At 293 K and < 3% relative humidity (RH), the measured uptake coefficients for six alkylamides were in the range of (4...
September 14, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28904378/end-cretaceous-akagan%C3%A3-ite-as-a-mineral-marker-of-deccan-volcanism-in-the-sedimentary-record
#11
Eric Font, Julie Carlut, Céline Rémazeilles, Tamsin A Mather, Anne Nédélec, José Mirão, Sandra Casale
An enigmatic chloride-rich iron (oxyhydr)oxide has been recently identified together with mercury anomalies in End-Cretaceous marine sediments coeval with the Deccan Traps eruptions. The mineral was observed in Bidart (France) and Gubbio (Italy), suggesting a widespread phenomenon. However, the exact nature and origin of this Cl-bearing mineral remained speculative. Here, we characterized the accurate composition and nanostructure of this chloride-rich phase by using micro-Raman spectroscopy, Transmission (TEM) and Scanning (SEM) Electron Microscopy on Focused Ion Beam foils...
September 13, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28902512/cloud-processing-of-secondary-organic-aerosol-from-isoprene-and-methacrolein-photooxidation
#12
Chiara Giorio, Anne Monod, Lola Brégonzio-Rozier, Helen Langley DeWitt, Mathieu Cazaunau, Brice Temime-Roussel, Aline Gratien, Vincent Michoud, Edouard Pangui, Sylvain Ravier, Arthur T Zielinski, Andrea Tapparo, Reinhilde Vermeylen, Magda Claeys, Didier Voisin, Markus Kalberer, Jean-Francois Doussin
Aerosol-cloud interaction contributes to the largest uncertainties in the estimation and interpretation of the Earth's changing energy budget. The present study explores experimentally the impacts of water condensation evaporation events, mimicking processes occurring in atmospheric clouds, on the molecular composition of secondary organic aerosol (SOA) from the photooxidation of methacrolein. A range of on- and off-line mass spectrometry techniques were used to obtain a detailed chemical characterization of SOA formed in control experiments in dry conditions, in triphasic experiments, i...
September 13, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28902199/tuning-the-electronic-structure-in-stanene-graphene-bilayers-using-strain-and-gas-adsorption
#13
Frank F Yun, D L Cortie, X L Wang
Epitaxial growth of stanene monolayers on graphene substrates is an attractive synthesis route for atomically-thin electronic components, however, it remains unclear how such composites will tolerate lattice strain and exposure to ambient atmosphere. Using density functional theory, we identified several epitaxial configurations for the stanene-graphene bilayer system and determined the effect of strain and water adsorption. In addition to previously reported co-aligned bilayers, we identify a second family of low energy structures involving rotation of one layer by thirty degrees...
September 13, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28900253/leaf-thermotolerance-in-tropical-trees-from-a-seasonally-dry-climate-varies-along-the-slow-fast-resource-acquisition-spectrum
#14
Aniruddh Sastry, Deepak Barua
Knowledge of the upper limits of temperature tolerance is essential to understand how tropical trees will respond to global warming. We quantified leaf thermotolerance in 41 tree species growing in a seasonally dry tropical region of the Indian subcontinent to examine: (1) differences between evergreen and deciduous species; (2) relationships with leaf mass per area (LMA) and leaf size; and, (3) seasonal variation in thermotolerance. Thermotolerance ranged from 45.5 °C to 50.5 °C among species, was higher for evergreen than deciduous species, and was negatively related to a continuous estimate of deciduousness...
September 12, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28894096/aerosols-as-a-source-of-dissolved-black-carbon-to-the-ocean
#15
Hongyan Bao, Jutta Niggemann, Li Luo, Thorsten Dittmar, Shuh-Ji Kao
Dissolved black carbon (DBC) is the largest known slow-cycling organic carbon pool in the world's oceans. Atmospheric deposition could significantly contribute to the oceanic DBC pool, but respective information is lacking. Here we estimate that, during the dust outbreak season, the atmospheric dry deposition of water-soluble black carbon (WSBC) is ~ 40% of the riverine input to the China coastal seas. The molecular composition of atmospheric WSBC determined by ultrahigh-resolution mass spectrometry, reveals similar soil-derived sources as for riverine discharge...
September 11, 2017: Nature Communications
https://www.readbyqxmd.com/read/28892860/fine-particles-at-a-background-site-in-central-france-chemical-compositions-seasonal-variations-and-pollution-events
#16
Lin He, Hui Chen, Jérôme Rangognio, Abderrazak Yahyaoui, Patrice Colin, Jinhe Wang, Véronique Daële, Abdelwahid Mellouki
To expand our knowledge of regional fine particles in Central France (Centre-Val de Loire region), a field observation study of PM2.5 was carried out at Verneuil site (46.81467N, 2.61012E, 180m.a.s.l.) from 2011 to 2014. The mass concentrations of water-soluble inorganic ions (WSIIs), organic carbon (OC), elemental carbon (EC) and biomass burning tracer (Levoglucosan) in PM2.5 were measured. Annual average PM2.5 mass concentrations were 11.8, 9.5, 12.6 and 10.2μg·m(-3) in 2011, 2012, 2013 and 2014, respectively, three of four higher than the WHO guideline of 10μg·m(-3)...
September 7, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28887942/radiation-transport-simulation-of-the-martian-gcr-surface-flux-and-dose-estimation-using-spherical-geometry-in-phits-compared-to-msl-rad-measurements
#17
John Flores-McLaughlin
Planetary bodies and spacecraft are predominantly exposed to isotropic radiation environments that are subject to transport and interaction in various material compositions and geometries. Specifically, the Martian surface radiation environment is composed of galactic cosmic radiation, secondary particles produced by their interaction with the Martian atmosphere, albedo particles from the Martian regolith and occasional solar particle events. Despite this complex physical environment with potentially significant locational and geometric dependencies, computational resources often limit radiation environment calculations to a one-dimensional or slab geometry specification...
August 2017: Life Sciences in Space Research
https://www.readbyqxmd.com/read/28887940/evaluation-of-hzetrn-on-the-martian-surface-sensitivity-tests-and-model-results
#18
Tony C Slaba, Nicholas N Stoffle
The Mars Science Laboratory Radiation Assessment Detector (MSLRAD) is providing continuous measurements of dose, dose equivalent, and particle flux on the surface of Mars. These measurements have been highly useful in validating environmental and radiation transport models that will be heavily relied upon for future deep space missions. In this work, the HZETRN code is utilized to estimate radiation quantities of interest on the Martian surface. A description of the modeling approach used with HZETRN is given along with the various input models and parameters used to define the galactic cosmic ray (GCR) environment and Martian geometry...
August 2017: Life Sciences in Space Research
https://www.readbyqxmd.com/read/28887380/proteomic-signature-reveals-modulation-of-human-macrophage-polarization-and-functions-under-differing-environmental-oxygen-conditions
#19
Magali Court, Graciane Petre, Michèle El-Atifi, Arnaud Millet
Macrophages are innate immune cells which can react to a large number of environmental stimuli thanks to a high degree of plasticity. These cells are involved in a variety of tissue functions in homeostasis, and they play essential roles in pathological contexts. Macrophages’ activation state, which determines their functional orientation, is strongly influenced by the cellular environment. A large body of macrophage literature is devoted to better defining polarizations from a molecular viewpoint. It is now accepted that a multidimensional model of polarization is needed to grasp the broad phenotype repertoire controlled by environmental signals...
September 8, 2017: Molecular & Cellular Proteomics: MCP
https://www.readbyqxmd.com/read/28885688/changes-in-physiological-and-some-nutritional-nutraceuticals-chemical-physical-microbiological-and-sensory-quality-minimally-processed-cactus-pears-cvs-bianca-gialla-and-rossa-stored-under-passive-modified-atmosphere
#20
Amedeo Palma, Alberto Continella, Stefano La Malfa, Salvatore D'Aquino
BACKGROUND: Objective of this study was to compare the overall quality changes of minimally processed cactus pears cvs. 'Bianca', Gialla' and 'Rossa' stored at 4 °C for 10 d. Periodically in-package CO2 , O2 and C2 H4 were determined and fruit were assessed for overall quality changes (pH, acidity, sugars, phenolics, betacyanins and betaxantines, antioxidant capacity, colour, firmness, microbiological population and sensory attributes). In a preliminary study three different polymeric films were tested to select the most suitable to design a package with a short lag time to achieve steady state conditions...
September 8, 2017: Journal of the Science of Food and Agriculture
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