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Chuchu Huang, Qing Li, Jiamei Mo, Zheng Wang
We herein describe a novel method of hydride generation (HG) coupled to a newly designed atmospheric pressure solution-cathode glow discharge (SCGD) spectrometric technique for the ultratrace determination of tin, germanium, and selenium. In this novel SCGD process, gas introduction was permitted using a hollow titanium tube as both the anode and sampling port. In these experiments, the analytes were converted into volatile hydrides upon passing through the hydride generator, and were introduced into the near-anode region of the SCGD system, where they were detected directly by atomic emission spectrometry (AES)...
October 25, 2016: Analytical Chemistry
Arvo Tullus, Priit Kupper, Ants Kaasik, Hardi Tullus, Krista Lõhmus, Anu Sõber, Arne Sellin
The interactive effects of climate variables and tree-tree competition are still insufficiently understood drivers of forest response to global climate change. Precipitation and air humidity are predicted to rise concurrently at high latitudes of the Northern Hemisphere. We investigated if the growth response of deciduous trees to elevated air humidity varies with their competitive status. The study was conducted in seed-originated silver birch and monoclonal hybrid aspen stands grown at the Free Air Humidity Manipulation (FAHM) experimental site in Estonia, in which manipulated stands (n = 3 for both species) are exposed to artificially elevated relative air humidity (6-7% over the ambient level)...
October 25, 2016: Global Change Biology
Tao-Tao Liu, Jun Liang, Yuan-Biao Huang, Rong Cao
A bifunctional cationic porous organic polymer based on a Salen-(Al) metalloligand (Al-CPOP) containing imidazolium functionality exhibited enhanced activity and good recyclability in the cycloaddition of carbon dioxide to produce cyclic carbonates without the addition of co-catalysts at atmospheric pressure.
October 25, 2016: Chemical Communications: Chem Comm
Pyeong-Koo Lee, Soonyoung Yu, Hye Jung Chang, Hye Young Cho, Min-Ju Kang, Byung-Gon Chae
Spherical black carbon aggregates were frequently observed in dust dry deposition in Daejeon, Korea. They were tens of micrometers in diameter and presented a mixture of black carbon and several mineral phases. Transmission electron microscopy (TEM) observations with energy-dispersive X-ray spectroscopy (EDS) and selected area diffraction pattern (SADP) analyses confirmed that the aggregates were compact and included significant amounts of lead chromate (PbCrO4). The compositions and morphologies of the nanosized lead chromate particles suggest that they probably originated from traffic paint used in roads and were combined as discrete minerals with black carbon...
October 25, 2016: Scientific Reports
Dong Xiao, Ping Zhao, Yue Wang, Xiuji Zhou
This study investigates the response of large-scale atmospheric circulation over the Asian-Pacific sector and precipitation over eastern China to transient orbital changes during the Holocene summer using an intermediate-complexity climate model. Corresponding to variations in the incoming solar radiation, the eddy sea level pressure (SLP) exhibited an out-of-phase relationship between the North Pacific and the Eurasian landmass that was similar to the present-day Asia-Pacific Oscillation (APO) pattern and was defined as the paleo-APO...
October 25, 2016: Scientific Reports
Yancheng Zhang, Xu Zhang, Cristiano M Chiessi, Stefan Mulitza, Xiao Zhang, Gerrit Lohmann, Matthias Prange, Hermann Behling, Matthias Zabel, Aline Govin, André O Sawakuchi, Francisco W Cruz, Gerold Wefer
Abundant hydroclimatic evidence from western Amazonia and the adjacent Andes documents wet conditions during Heinrich Stadial 1 (HS1, 18-15 ka), a cold period in the high latitudes of the North Atlantic. This precipitation anomaly was attributed to a strengthening of the South American summer monsoon due to a change in the Atlantic interhemispheric sea surface temperature (SST) gradient. However, the physical viability of this mechanism has never been rigorously tested. We address this issue by combining a thorough compilation of tropical South American paleorecords and a set of atmosphere model sensitivity experiments...
October 25, 2016: Scientific Reports
Ji Hoon Park, Minsup Kim, Masaharu Shiratani, Art E Cho, Eun Ha Choi, Pankaj Attri
Over the last few years, the variation in liquid chemistry due to the development of radicals generated by cold atmospheric plasma (CAP) has played an important role in plasma medicine. CAP direct treatment or CAP activated media treatment in cancer cells shows promising anticancer activity for both in vivo and in vitro studies. However, the anticancer activity or antimicrobial activity varies between plasma devices due to the different abilities among plasma devices to generate the reactive oxygen and nitrogen species (RONS) at different ratios and in different concentrations...
October 25, 2016: Scientific Reports
Zhenchuan Niu, Weijian Zhou, Peng Cheng, Shugang Wu, Xuefeng Lu, Xiaohu Xiong, Hua Du, Yunchong Fu
Six months to more than one year of atmospheric Δ14CO2 were measured in 2014-2015 at one global background site in Waliguan (WLG) and four regional background sites at Shangdianzi (SDZ), Lin'an (LAN), Longfengshan (LFS) and Luhuitou (LHT), China. The objectives of the study are to document the Δ14CO2 background levels at each site and to trace the variations in fossil fuel CO2 (CO2ff) inputs at regional background sites. Δ14CO2 at WLG varied from 7.1±2.9‰ to 32.0±3.2‰ (average 17.1±6.8‰) in 2015, with high values generally in autumn/summer and low values in winter/spring...
October 25, 2016: Environmental Science & Technology
Bruno Gamarra, Ansgar Kahmen
RATIONALE: Leaf wax n-alkanes are long-chained aliphatic compounds that are present in the cuticle of terrestrial plant leaves. Their δ(2) H values are used for the reconstruction of past environments and for plant ecological investigations. The timing of n-alkane synthesis during leaf development and the rate of synthesis of secondary n-alkanes in fully matured leaves are still a matter of debate. METHODS: Using a (2) H-labeling approach we estimated secondary leaf wax n-alkane synthesis rates in mature leaf blades of six C3 grass species grown in climate chambers under controlled environmental conditions...
October 25, 2016: Rapid Communications in Mass Spectrometry: RCM
Garold Murdachaew, Gilbert M Nathanson, R Benny Gerber, Lauri Halonen
Deprotonation of organic acids at aqueous surfaces has important implications in atmospheric chemistry and other disciplines, yet it is not well-characterized or understood. This article explores the interactions of formic acid (FA), including ionization, in collisions at the air-water interface. Ab initio molecular dynamics simulations with dispersion-corrected density functional theory were used. The 8-50 picosecond duration trajectories all resulted in the adsorption of FA within the interfacial region, with no scattering, absorption into the bulk or desorption into the vapor...
October 25, 2016: Physical Chemistry Chemical Physics: PCCP
Hannah E Aichelman, Joseph E Townsend, Travis A Courtney, Justin H Baumann, Sarah W Davies, Karl D Castillo
Anthropogenic increases in atmospheric carbon dioxide concentration have caused global average sea surface temperature (SST) to increase by approximately 0.11°C per decade between 1971 and 2010 - a trend that is projected to continue through the 21st century. A multitude of research studies have demonstrated that increased SSTs compromise the coral holobiont (cnidarian host and its symbiotic algae) by reducing both host calcification and symbiont density, among other variables. However, we still do not fully understand the role of heterotrophy in the response of the coral holobiont to elevated temperature, particularly for temperate corals...
September 2016: Ecology and Evolution
Jian Wang, Radovan Krejci, Scott Giangrande, Chongai Kuang, Henrique M J Barbosa, Joel Brito, Samara Carbone, Xuguang Chi, Jennifer Comstock, Florian Ditas, Jost Lavric, Hanna E Manninen, Fan Mei, Daniel Moran-Zuloaga, Christopher Pöhlker, Mira L Pöhlker, Jorge Saturno, Beat Schmid, Rodrigo A F Souza, Stephen R Springston, Jason M Tomlinson, Tami Toto, David Walter, Daniela Wimmer, James N Smith, Markku Kulmala, Luiz A T Machado, Paulo Artaxo, Meinrat O Andreae, Tuukka Petäjä, Scot T Martin
The nucleation of atmospheric vapours is an important source of new aerosol particles that can subsequently grow to form cloud condensation nuclei in the atmosphere. Most field studies of atmospheric aerosols over continents are influenced by atmospheric vapours of anthropogenic origin (for example, ref. 2) and, in consequence, aerosol processes in pristine, terrestrial environments remain poorly understood. The Amazon rainforest is one of the few continental regions where aerosol particles and their precursors can be studied under near-natural conditions, but the origin of small aerosol particles that grow into cloud condensation nuclei in the Amazon boundary layer remains unclear...
October 24, 2016: Nature
Shaw D Bamber, Stig Westerlund
Sub-sea geological storage of carbon dioxide (CO2) provides a viable option for the Carbon Capture and Storage (CCS) approach for reducing atmospheric emissions of this greenhouse gas. Although generally considered to offer a low risk of major leakage, it remains relevant to establish the possible consequences for marine organisms that live in or on sediments overlying these storage areas if such an event may occur. The present study has used a series of laboratory exposures and behavioral bioassays to establish the sensitivity of Arctica islandica to simulated leakages of CO2...
October 11, 2016: Aquatic Toxicology
Karell Martínez-Guijarro, Ashraf Ramadan, Bondi Gevao
A sampling campaign was carried out to assess the impact of the oil field activities on the concentrations of polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (dl-PCBs) in ambient air at Umm Al-Aish oil field in northern Kuwait. Sixteen samples were collected from March 2014 to January 2015. The concentrations of ΣPCDD/Fs were relatively high (33.6-586 fg I-TEQ/m(3); median: 94.7 fg I-TEQ/m(3); 31.2 to 516 fg WHO-TEQ2005/m(3); median: 83...
October 21, 2016: Chemosphere
Xiaolan Zeng, Jing Chen, Ruijuan Qu, Xiaoxue Pan, Zunyao Wang
The atmospheric chemical reactions of some polyfluorinated dibenzofurans (PFDFs) and polychlorinated dibenzofurans (PCDFs), initiated by OH radical, were investigated by performing theoretical calculations using density functional theory (DFT) and B3LYP/6-311++G(2df,p) method. The obtained results indicate that OH addition reactions of PFDFs and PCDFs occurring at C1∼4 and CA sites are thermodynamic spontaneous changes and the branching ratio of the PF(C)DF-OH adducts is decided primarily by kinetic factor...
October 21, 2016: Chemosphere
Chen Wang, Ying Duan Lei, Frank Wania
Dissolved inorganic salt(s) influence the partitioning of organic compounds into the aqueous phase. This influence is especially significant in atmospheric aerosol, which usually contains large amount of ions, including sodium, ammonium, chloride, sulfate and nitrate. However, empirical data on this salt effect are very sparse. Here, the partitioning of numerous organic compounds into solutions of Na2SO4, NH4Cl and NH4NO3 was measured and compared with existing data for NaCl and (NH4)2SO4. Salt mixtures were also tested in order to establish whether the salt effect is additive...
October 24, 2016: Environmental Science & Technology
Jillian M Petersen, Anna Kemper, Harald Gruber-Vodicka, Ulisse Cardini, Matthijs van der Geest, Manuel Kleiner, Silvia Bulgheresi, Marc Mußmann, Craig Herbold, Brandon K B Seah, Chakkiath Paul Antony, Dan Liu, Alexandra Belitz, Miriam Weber
Chemosynthetic symbioses are partnerships between invertebrate animals and chemosynthetic bacteria. The latter are the primary producers, providing most of the organic carbon needed for the animal host's nutrition. We sequenced genomes of the chemosynthetic symbionts from the lucinid bivalve Loripes lucinalis and the stilbonematid nematode Laxus oneistus. The symbionts of both host species encoded nitrogen fixation genes. This is remarkable as no marine chemosynthetic symbiont was previously known to be capable of nitrogen fixation...
October 24, 2016: Nature Microbiology
Mauro Zaninelli, Veronica Redaelli, Erica Tirloni, Cristian Bernardi, Vittorio Dell'Orto, Giovanni Savoini
The development of a monitoring system to identify the presence of laying hens, in a closed room of a free-range commercial organic egg production farm, was the aim of this study. This monitoring system was based on the infrared (IR) technology and had, as final target, a possible reduction of atmospheric ammonia levels and bacterial load. Tests were carried out for three weeks and involved 7 ISA (Institut de Sélection Animale) brown laying hens. The first 5 days was used to set up the detection sensor, while the other 15 days were used to evaluate the accuracy of the resulting monitoring system, in terms of sensitivity and specificity...
October 21, 2016: Sensors
Shijiao Han, Jiang Cheng, Huidong Fan, Junsheng Yu, Lu Li
High-response organic field-effect transistor (OFET)-based NO₂ sensors were fabricated using the synergistic effect the synergistic effect of zinc oxide/poly(methyl methacrylate) (ZnO/PMMA) hybrid dielectric and CuPc/Pentacene heterojunction. Compared with the OFET sensors without synergistic effect, the fabricated OFET sensors showed a remarkable shift of saturation current, field-effect mobility and threshold voltage when exposed to various concentrations of NO₂ analyte. Moreover, after being stored in atmosphere for 30 days, the variation of saturation current increased more than 10 folds at 0...
October 21, 2016: Sensors
Encheng Xin, Yong Ju, Haiwen Yuan
A space charge density wireless measurement system based on the idea of distributed measurement is proposed for collecting and monitoring the space charge density in an ultra-high-voltage direct-current (UHVDC) environment. The proposed system architecture is composed of a number of wireless nodes connected with space charge density sensors and a base station. The space charge density sensor based on atmospheric ion counter method is elaborated and developed, and the ARM microprocessor and Zigbee radio frequency module are applied...
October 20, 2016: Sensors
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