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https://www.readbyqxmd.com/read/29793196/seasonal-cycles-of-secondary-organic-aerosol-tracers-in-rural-guangzhou-southern-china-the-importance-of-atmospheric-oxidants
#1
Qi Yuan, Senchao Lai, Junwei Song, Xiang Ding, Lishan Zheng, Xinming Wang, Yan Zhao, Junyu Zheng, Dingli Yue, Liuju Zhong, Xiaojun Niu, Yingyi Zhang
Thirteen secondary organic aerosol (SOA) tracers of isoprene (SOAI ), monoterpenes (SOAM ), sesquiterpenes (SOAS ) and aromatics (SOAA ) in fine particulate matter (PM2.5 ) were measured at a Pearl River Delta (PRD) regional site for one year. The characteristics including their seasonal cycles and the factors influencing their formation in this region were studied. The seasonal patterns of SOAI , SOAM and SOAS tracers were characterized over three enhancement periods in summer (I), autumn (II) and winter (III), while the elevations of SOAA tracer (i...
May 21, 2018: Environmental Pollution
https://www.readbyqxmd.com/read/29793082/atmospheric-impacts-of-a-natural-gas-development-within-the-urban-context-of-morgantown-west-virginia
#2
Philip J Williams, Matthew Reeder, Natalie J Pekney, David Risk, John Osborne, Michael McCawley
The Marcellus Shale Energy and Environment Laboratory (MSEEL) in West Virginia provides a unique opportunity in the field of unconventional energy research. By studying near-surface atmospheric chemistry over several phases of a hydraulic fracturing event, the project will help evaluate the impact of current practices, as well as new techniques and mitigation technologies. A total of 10 mobile surveys covering a distance of approximately 1500 km were conducted through Morgantown. Our surveying technique involved using a vehicle-mounted Los Gatos Research gas analyzer to provide geo-located measurements of methane (CH4 ) and carbon dioxide (CO2 )...
May 21, 2018: Science of the Total Environment
https://www.readbyqxmd.com/read/29792755/dalangtan-saline-playa-in-a-hyperarid-region-on-tibet-plateau-i-evolution-and-environments
#3
Fanjing Kong, Mianping Zheng, Bin Hu, Alian Wang, Nina Ma, Pablo Sobron
Since 2008, we have been studying a saline lake, Dalangtan (DLT) Playa, and its surroundings in a hyperarid region of the Qaidam Basin on the Tibetan Plateau as a potential Mars analog site. We describe the evolution of saline deposits in the Qaidam Basin (including DLT), based on investigative findings accumulated over the course of 60 years of geological surveys. In addition, we report regional meteorological patterns recorded for the past 32 years along with meteorological station recorded data at DLT since 2012...
May 24, 2018: Astrobiology
https://www.readbyqxmd.com/read/29792704/double-hydrogen-atom-exchange-reactions-of-hx-x-f-cl-br-i-with-ho2
#4
Rex T Skodje, Jonathan R Church
A novel double hydrogen atom exchange process, HX+H'O2H'X+HO2 for the halogen series X=F, Cl, Br, and I, is identified using theoretical methods. These concerted reactions are mediated through a stabilized five-member planar ring transition state structure. The transition state barrier for the double exchange process is found to be significantly lower than that for the abstraction reaction of a single hydrogen atom, . Density functional theory employing the M11 exchange functional is used to compute parameters of the potential energy surface and the rate coefficients are obtained using transition state theory with small curvature tunneling...
May 24, 2018: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/29792673/recent-advances-on-sodium-oxygen-batteries-a-chemical-perspective
#5
Hossein Yadegari, Xueliang Sun
Releasing greenhouse gases into the atmosphere because of widespread use of fossil fuels by humankind has resulted in raising the earth's temperature during the past few decades. Known as global warming, increasing the earth's temperature may in turn endanger civilization on the earth by starting a cycle of environmental changes including climate change and sea level rise. Therefore, replacing fossil fuels with more sustainable energy resources has been considered as one of the main strategies to tackle the global warming crisis...
May 24, 2018: Accounts of Chemical Research
https://www.readbyqxmd.com/read/29791884/rainfall-as-primary-driver-of-discharge-and-solute-export-from-rock-glaciers-the-col-d-olen-rock-glacier-in-the-nw-italian-alps
#6
Nicola Colombo, Stephan Gruber, Maria Martin, Mery Malandrino, Andrea Magnani, Danilo Godone, Michele Freppaz, Simona Fratianni, Franco Salerno
Three hypotheses exist to explain how meteorological variables drive the amount and concentration of solute-enriched water from rock glaciers: (1) Warm periods cause increased subsurface ice melt, which releases solutes; (2) rain periods and the melt of long-lasting snow enhance dilution of rock-glacier outflows; and (3) percolation of rain through rock glaciers facilitates the export of solutes, causing an opposite effect as that described in hypothesis (2). This lack of detailed understanding likely exists because suitable studies of meteorological variables, hydrologic processes and chemical characteristics of water bodies downstream from rock glaciers are unavailable...
May 20, 2018: Science of the Total Environment
https://www.readbyqxmd.com/read/29791370/band-optimization-of-passive-methane-gas-leak-detection-based-on-uncooled-infrared-focal-plane-array
#7
Zhang Xu, Weiqi Jin, Li Li, Xia Wang, Ji Chen, YuChao Jia
Current methane gas leak detection technology uses infrared imaging in the medium wave (MW) or long wave (LW) bands, essentially applying cooled infrared detectors. In this study, a simplified three-layer radiative transfer model is adopted based on methane gas detection theory, considering background radiation, atmospheric infrared absorption, gas absorption, and emission characteristics to analyze the contrast of methane gas thermography in different infrared bands. The analysis results suggest that under certain conditions, the 6...
May 20, 2018: Applied Optics
https://www.readbyqxmd.com/read/29791333/modeling-of-microjoule-and-millijoule-energy-lidars-with-pmt-sipm-apd-detectors-a-sensitivity-analysis
#8
Ravil Agishev
This paper demonstrates a renewed concept and applications of the generalized methodology for atmospheric light detection and ranging (LIDAR) capability prediction as a continuation of a series of our previous works, where the dimensionless parameterization appeared as a tool for comparing systems of a different scale, design, and applications. The modernized concept applied to microscale and milliscale LIDARs with relatively new silicon photomultiplier detectors and traditional photomultiplier tube and avalanche photodiode detectors allowed prediction of the remote sensing instruments' performance and limitations...
May 10, 2018: Applied Optics
https://www.readbyqxmd.com/read/29791235/long-term-planetary-habitability-and-the-carbonate-silicate-cycle
#9
Andrew J Rushby, Martin Johnson, Benjamin J W Mills, Andrew J Watson, Mark W Claire
The potential habitability of an exoplanet is traditionally assessed by determining whether its orbit falls within the circumstellar "habitable zone" of its star, defined as the distance at which water could be liquid on the surface of a planet (Kopparapu et al., 2013 ). Traditionally, these limits are determined by radiative-convective climate models, which are used to predict surface temperatures at user-specified levels of greenhouse gases. This approach ignores the vital question of the (bio)geochemical plausibility of the proposed chemical abundances...
May 2018: Astrobiology
https://www.readbyqxmd.com/read/29791234/searching-for-the-great-oxidation-event-in-north-america-a-reappraisal-of-the-huronian-supergroup-by-sims-sulfur-four-isotope-analysis
#10
Huan Cui, Kouki Kitajima, Michael J Spicuzza, John H Fournelle, Akizumi Ishida, Philip E Brown, John W Valley
Sedimentological observations from the Paleoproterozoic Huronian Supergroup are suggested to mark the rise in atmospheric oxygen at that time, which is commonly known as the Great Oxidation Event (GOE) and typically coupled with a transition from mass-independent fractionation (MIF) to mass-dependent fractionation (MDF) of sulfur isotopes. An early in situ study of S three-isotopes across the Huronian Supergroup by Papineau et al. ( 2007 ) identified a weak MIF-MDF transition. However, the interpretation and stratigraphic placement of this transition is ambiguous...
May 2018: Astrobiology
https://www.readbyqxmd.com/read/29791052/high-performance-liquid-chromatography-quantification-of-enantiomers-of-a-dihydroxylated-tetrahydrofuran-natural-product
#11
Ke Li, Skye D Fissette, Tyler J Buchinger, Zoe E Middleton, Alistair Boyer, Weiming Li
Both enantiomers of petromyroxol are putative pheromones in sea lamprey (Petromyzon marinus). Here, we describe the separation and quantification of the petromyroxol enantiomers using high-performance liquid chromatography tandem mass spectrometry. The separation was tested on a wide range of chiral columns with normal phases, and effects of the chromatographic parameters such as mobile phase and temperature on the separation were optimized. The AD-H column showed the best separation of enantiomers with n-hexane and ethanol as the mobile phase...
May 23, 2018: Chirality
https://www.readbyqxmd.com/read/29791031/ocean-acidification-stimulates-particulate-organic-carbon-accumulation-in-two-antarctic-diatom-species-under-moderate-and-high-natural-solar-radiation
#12
Jasmin P Heiden, Silke Thoms, Kai Bischof, Scarlett Trimborn
Impacts of rising atmospheric CO2 concentrations and increased daily irradiances from enhanced surface water stratification on phytoplankton physiology in the coastal Southern Ocean remain still unclear. Therefore, in the two Antarctic diatoms Fragilariopsis curta and Odontella weissflogii the effects of moderate and high natural solar radiation combined with either ambient or future pCO2 on cellular particulate organic carbon (POC) contents and photophysiology were investigated. Results showed that increasing CO2 concentrations had greater impacts on diatom physiology than exposure to increasing solar radiation...
May 23, 2018: Journal of Phycology
https://www.readbyqxmd.com/read/29790336/importance-of-dermal-absorption-of-polycyclic-aromatic-hydrocarbons-derived-from-barbecue-fumes
#13
Jia-Yong Lao, Shan-Yi Xie, Chen-Chou Wu, Lian-Jun Bao, Shu Tao, Eddy Y Zeng
Despite the ubiquity and carcinogenicity of polycyclic aromatic hydrocarbons (PAHs), their dermal absorption for the general population has not been adequately addressed. Aiming to verify the importance of dermal absorption of PAHs, barbecue (BBQ) in Guangzhou, China was chosen as a case study. Urine samples were collected and analyzed for nine hydroxyl (OH)-PAHs. Air, food, and cotton clothing samples were analyzed for 16 PAHs. Dietary exposure was the dominant exposure route with the greatest amounts of OH-PAH excretion and PAH intake...
May 23, 2018: Environmental Science & Technology
https://www.readbyqxmd.com/read/29789621/taxon-specific-aerosolization-of-bacteria-and-viruses-in-an-experimental-ocean-atmosphere-mesocosm
#14
Jennifer M Michaud, Luke R Thompson, Drishti Kaul, Josh L Espinoza, R Alexander Richter, Zhenjiang Zech Xu, Christopher Lee, Kevin M Pham, Charlotte M Beall, Francesca Malfatti, Farooq Azam, Rob Knight, Michael D Burkart, Christopher L Dupont, Kimberly A Prather
Ocean-derived, airborne microbes play important roles in Earth's climate system and human health, yet little is known about factors controlling their transfer from the ocean to the atmosphere. Here, we study microbiomes of isolated sea spray aerosol (SSA) collected in a unique ocean-atmosphere facility and demonstrate taxon-specific aerosolization of bacteria and viruses. These trends are conserved within taxonomic orders and classes, and temporal variation in aerosolization is similarly shared by related taxa...
May 22, 2018: Nature Communications
https://www.readbyqxmd.com/read/29789456/human-health-risk-assessment-of-toxic-elements-in-farmland-topsoil-with-source-identification-in-jilin-province-china
#15
Fengxu Li, Jiquan Zhang, Tiehua Cao, Sijia Li, Yanan Chen, Xuanhe Liang, Xin Zhao, Junwei Chen
The presence of toxic elements in agricultural soils from anthropogenic activities is a potential threat to human health through the food chain. In this study, the concentration of toxic elements in 122 agricultural topsoil composite samples were determined in order to study the current status, identify their sources and assess the level of pollution and human health risk. The results showed that the mean concentrations of Zn, Cu, Pb, Cd, Hg and As in the farmland topsoil were 21.72, 15.09, 36.08, 0.2451, 0...
May 22, 2018: International Journal of Environmental Research and Public Health
https://www.readbyqxmd.com/read/29789135/combined-effects-of-ocean-acidification-and-temperature-on-planula-larvae-of-the-moon-jellyfish-aurelia-coerulea
#16
Zhijun Dong, Tingting Sun
Rapidly rising levels of atmospheric CO2 have caused two environmental stressors, ocean acidification and seawater temperature increases, which represent major abiotic threats to marine organisms. Here, we investigated for the first time the combined effects of ocean acidification and seawater temperature increases on the behavior, survival, and settlement of the planula larvae of Aurelia coerulea, which is considered a nuisance species around the world. Three pH levels (8.1, 7.7 and 7.3) and two temperature levels (24 °C and 27 °C) were used in the present study...
May 16, 2018: Marine Environmental Research
https://www.readbyqxmd.com/read/29789085/acute-exposure-to-low-to-moderate-carbon-dioxide-levels-and-submariner-decision-making
#17
Christopher D Rodeheffer, Sarah Chabal, John M Clarke, David M Fothergill
BACKGROUND: Submarines routinely operate with higher levels of ambient carbon dioxide (CO2) (i.e., 2000 - 5000 ppm) than what is typically considered normal (i.e., 400 - 600 ppm). Although significant cognitive impairments are rarely reported at these elevated CO2 levels, recent studies using the Strategic Management Simulation (SMS) test have found impairments in decision-making performance during acute CO2 exposure at levels as low as 1000 ppm. This is a potential concern for submarine operations, as personnel regularly make mission-critical decisions that affect the safety and efficiency of the vessel and its crew while exposed to similar levels of CO2...
June 1, 2018: Aerospace Medicine and Human Performance
https://www.readbyqxmd.com/read/29788713/tribochemical-competition-within-a-mos2-ti-dry-lubricated-macroscale-contact-in-ultrahigh-vacuum-a-time-of-flight-secondary-ion-mass-spectrometry-investigation
#18
Guillaume Colas, Aurélien Saulot, David Philippon, Yves Berthier, Didier Leonard
Controlling and predicting the tribological behavior of dry lubricant is a necessity to ensure low friction, long life, and low particle generation. Understanding the tribochemistry of the materials as a function of the environment is of primary interest as synergistic effects exist between the mechanics, the physicochemistry, the thermodynamics within a contact. However, in most studies the role of the coating internal contaminants in the process is often discarded to the benefit of a more common approach in which the performances of the materials are compared as a function of different atmospheric pressure environments...
May 23, 2018: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/29788326/in-situ-transmission-electron-microscopic-observations-of-redox-cycling-of-a-ni-scsz-cermet-fuel-cell-anode
#19
Junko Matsuda, Tatsuya Kawasaki, Shotaro Futamura, Tsutomu Kawabata, Shunsuke Taniguchi, Kazunari Sasaki
In situ transmission electron microscopy (TEM) observations of a Ni(O)-Sc2O3-stabilized ZrO2 (ScSZ; 10 mol% Sc2O3, 1 mol% CeO2, 89 mol% ZrO2) anode in a solid oxide fuel cell (SOFC) have been performed at high temperatures under a hydrogen/oxygen gas atmosphere using an environmental transmission electron microscope (ETEM); the specimens were removed from cross-sections of the real SOFC by focused ion beam milling and lifting. When heating the NiO-ScSZ anode under a hydrogen atmosphere of 3 mbar in ETEM, nano-pores were formed at the grain boundaries and on the surface of NiO particles at around 400°C due to the volume shrinkage accompanying the reduction of NiO to Ni...
May 19, 2018: Microscopy
https://www.readbyqxmd.com/read/29787994/bioavailability-of-wilforlide-a-in-mice-and-its-concentration-determination-using-an-hplc-apci-ms-ms-method
#20
Zhijun Wang, Steven Yeung, Shang Chen, Yasmin Moatazedi, Moses S S Chow
Wilforlide A (WA), an active compound in Tripterygium wilfordii Hook F (TW) which is a traditional Chinese medicine for treatment of autoimmune diseases, is a quality control marker for TW product. At present, the bioavailability/pharmacokinetics of WA is not known. Such information is not only essential to evaluate the relevance of WA as a quality control maker, but also important for future clinical efficacy studies. Therefore, a high-performance liquid chromatography-atmospheric pressure chemical ionization tandem mass spectrometric method (HPLC-APCI-MS/MS) was developed and applied to a bioavailability/pharmacokinetic study of WA...
May 16, 2018: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
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