keyword
MENU ▼
Read by QxMD icon Read
search

Chemical speciation

keyword
https://www.readbyqxmd.com/read/27934158/soft-x-ray-spectroscopy-of-a-complex-heterojunction-in-high-efficiency-thin-film-photovoltaics-intermixing-and-zn-speciation-at-the-zn-o-s-cu-in-ga-se2-interface
#1
Michelle Mezher, Rebekah Garris, Lorelle M Mansfield, Monika Blum, Dirk Hauschild, Kimberly Horsley, Douglas A Duncan, Wanli Yang, Marcus Bär, Lothar Weinhardt, Kannan Ramanathan, Clemens Heske
The chemical structure of the Zn(O,S)/Cu(In,Ga)Se2 interface in high-efficiency photovoltaic devices is investigated using X-ray photoelectron and Auger electron spectroscopy, as well as soft X-ray emission spectroscopy. We find that the Ga/(Ga+In) ratio at the absorber surface does not change with the formation of the Zn(O,S)/Cu(In,Ga)Se2 interface. Furthermore, we find evidence for Zn in multiple bonding environments, including ZnS, ZnO, Zn(OH)2, and ZnSe. We also observe dehydrogenation of the Zn(O,S) buffer layer after Ar(+) ion treatment...
December 7, 2016: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/27931881/pm2-5-source-attribution-for-seoul-in-may-from-2009-to-2013-using-geos-chem-and-its-adjoint-model
#2
Hyung-Min Lee, Rokjin J Park, Daven K Henze, Seungun Lee, Changsub Shim, Hye-Jung Shin, Kwang-Joo Moon, Jung-Hun Woo
Enforcement of an air quality standard for PM2.5 in the Seoul metropolitan area (SMA) was enacted in 2015. From May to June of 2016, an international airborne and surface measurement campaign took place to investigate air pollution mechanisms in the SMA. The total and speciated PM2.5 concentrations since 2008 have been measured at an intensive monitoring site for the SMA operated by the National Institute of Environmental Research (NIER). To gain insight on the trends and sources of PM2.5 in the SMA in May, we analyze PM2...
December 5, 2016: Environmental Pollution
https://www.readbyqxmd.com/read/27920386/does-eutrophication-driven-evolution-change-aquatic-ecosystems
#3
REVIEW
Timothy J Alexander, Pascal Vonlanthen, Ole Seehausen
Eutrophication increases primary production and changes the relative abundance, taxonomic composition and spatial distribution of primary producers within an aquatic ecosystem. The changes in composition and location of resources alter the distribution and flow of energy and biomass throughout the food web. Changes in productivity also alter the physico-chemical environment, which has further effects on the biota. Such ecological changes influence the direction and strength of natural and sexual selection experienced by populations...
January 19, 2017: Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
https://www.readbyqxmd.com/read/27914647/human-exposure-to-dietary-inorganic-arsenic-and-other-arsenic-species-state-of-knowledge-gaps-and-uncertainties
#4
Francesco Cubadda, Brian P Jackson, Kathryn L Cottingham, Yoshira Ornelas Van Horne, Margaret Kurzius-Spencer
Inorganic arsenic (iAs) is ubiquitous in the environment as arsenite (AsIII) and arsenate (AsV) compounds and biotransformation of these toxic chemicals leads to the extraordinary variety of organoarsenic species found in nature. Despite classification as a human carcinogen based on data from populations exposed through contaminated drinking water, only recently has a need for regulatory limits on iAs in food been recognized. The delay was due to the difficulty in risk assessment of dietary iAs, which critically relies on speciation analysis providing occurrence data for iAs in food - and not simply for total arsenic...
November 30, 2016: Science of the Total Environment
https://www.readbyqxmd.com/read/27909925/phosphate-fertilizer-affected-rhizospheric-soils-speciation-of-cadmium-and-phytoremediation-by-chlorophytum-comosum
#5
Youbao Wang, Chengfeng Zhu, Hongfei Yang, Xiaowei Zhang
Experiments were conducted to investigate the effect of phosphate fertilization on chemical speciation of cadmium (Cd) in the rhizospheric soil of Chlorophytum comosum, a potential cadmium hyperaccumulator. The results revealed that when 200 mg kg(-1) phosphate was applied into the soil, the Cd contents in the exchangeable fraction (EXC), carbonate-binding fraction (CA), and Fe-Mn oxides-binding fraction (Fe-Mn) were the highest, and the Cd content in the residual fraction (RES) was the lowest. Phosphate fertilization could enhance Cd conversion from RES into CA and weak RES, thereby improving the bioavailability of Cd and enhancing Cd enrichment and adsorption by C...
December 1, 2016: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/27909425/thermodynamic-and-kinetic-response-of-microbial-reactions-to-high-co2
#6
Qusheng Jin, Matthew F Kirk
Geological carbon sequestration captures CO2 from industrial sources and stores the CO2 in subsurface reservoirs, a viable strategy for mitigating global climate change. In assessing the environmental impact of the strategy, a key question is how microbial reactions respond to the elevated CO2 concentration. This study uses biogeochemical modeling to explore the influence of CO2 on the thermodynamics and kinetics of common microbial reactions in subsurface environments, including syntrophic oxidation, iron reduction, sulfate reduction, and methanogenesis...
2016: Frontiers in Microbiology
https://www.readbyqxmd.com/read/27902885/recent-advances-and-applications-of-gas-chromatography-vacuum-ultraviolet-spectroscopy
#7
REVIEW
Inês C Santos, Kevin A Schug
The vacuum ultraviolet spectrophotometer was developed recently as an alternative to existing gas chromatography detectors. This detector measures the absorption of gas-phase chemical species in the range of 120-240 nm, where all chemical compounds present unique absorption spectra. Therefore, qualitative analysis can be performed and quantification follows standard Beer-Lambert law principles. Different fields of application, such as petrochemical, food, and environmental analysis have been explored. Commonly demonstrated is the capability for facile deconvolution of co-eluting analytes...
November 7, 2016: Journal of Separation Science
https://www.readbyqxmd.com/read/27885365/hydrolysis-of-trivalent-plutonium-and-solubility-of-pu-oh-3-am-under-electrolytic-reducing-conditions
#8
Hye-Ryun Cho, Young-Sang Youn, Euo Chang Jung, Wansik Cha
The aim of this work is to determine the solubility product of plutonium hydroxide under reducing conditions and to ascertain the stability of Pu(OH)3 (am) in water. Hydrolysis of Pu(iii) and solubility of Pu(OH)3 (am) were investigated at a constant ionic strength of 0.1 M NaClO4. Coulometric titration was adopted to adjust the pH of plutonium solutions, during which the electrolytic reducing conditions maintained the oxidation state of Pu(iii). Chemical speciation for dissolved plutonium was investigated using sensitive spectrophotometry coupled with a liquid waveguide capillary cell...
November 25, 2016: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/27884489/geochemical-speciation-bioavailability-and-source-identification-of-selected-metals-in-surface-sediments-of-the-southern-caspian-sea
#9
Kazem Darvish Bastami, Mahmoud Reza Neyestani, Marjan Esmaeilzadeh, Sarah Haghparast, Camelia Alavi, Sanaz Fathi, Shahram Nourbakhsh, Emam Ali Shirzadi, Reyhane Parhizgar
Geochemical speciation of As, Cd, Co, Cr, Cu, Ni, Pb, V and Zn were determined in the surface sediments of the southern Caspian Sea. A five-step sequential extraction technique was used to determine the chemical forms of metals. Mean concentrations (ppm) of heavy metals were (mean±S.D.) As: 9.94±1.71, Cd: 0.87±0.23, Co: 14.85±2.80, Cr: 72.29±19.48, Cu: 18.91±4.48, Ni: 32.87±5.25, Pb: 12.48±3.22, V: 86.07±20.71 and Zn: 66.85±10.11. Among the metals, Cu, As, Pb and Zn exhibited relatively higher mobility, while Cd, Co, Cr, Ni and V were found mainly in the residual fractions...
November 21, 2016: Marine Pollution Bulletin
https://www.readbyqxmd.com/read/27880923/in-situ-speciation-of-uranium-in-treated-acid-mine-drainage-using-the-diffusion-gradients-in-thin-films-technique-dgt
#10
Jorge Henrique Pedrobom, Carlos Eduardo Eismann, Amauri A Menegário, Juliana Aparecida Galhardi, Karen Silva Luko, Thiago de Araujo Dourado, Chang Hung Kiang
The exchange membranes P81 and DE81 and Chelex-100 resin were used to perform in situ speciation of uranium in treated acid mine drainage at the Osamu Utsumi mining site, Poços de Caldas city, Southeast Brazil. To investigate possible chemical modifications in the samples during analysis, the three ligands were deployed in situ and in a laboratory (in lab). The results obtained in situ were also compared to a speciation performed using Visual MINTEQ software. Chelex-100 retained total labile U for a period of up to 48 h...
November 20, 2016: Chemosphere
https://www.readbyqxmd.com/read/27880879/arsenic-levels-among-pregnant-women-and-newborns-in-canada-results-from-the-maternal-infant-research-on-environmental-chemicals-mirec-cohort
#11
Adrienne S Ettinger, Tye E Arbuckle, Mandy Fisher, Chun Lei Liang, Karelyn Davis, Ciprian-Mihai Cirtiu, Patrick Bélanger, Alain LeBlanc, William D Fraser
Arsenic is a common environmental contaminant from both naturally-occurring and anthropomorphic sources and human exposure can be detected in various tissues. Its toxicity depends on many factors including the chemical form, valence state, bioavailability, metabolism and detoxification within the human body. Of paramount concern, particularly with respect to health effects in children, is the timing of exposure as the prenatal and early life periods are more susceptible to toxic effects. The Maternal-Infant Research on Environmental Chemicals (MIREC) cohort was established to obtain national-level biomonitoring data for approximately 2,000 pregnant women and their infants between 2008 and 2011 from 10 Canadian cities...
November 20, 2016: Environmental Research
https://www.readbyqxmd.com/read/27875717/comparative-study-on-the-mobility-and-speciation-of-heavy-metals-in-ashes-from-co-combustion-of-sewage-sludge-dredged-sludge-and-rice-husk
#12
Teng Wang, Yongjie Xue, Min Zhou, Yunjuan Yuan, Suyun Zhao, Gang Tan, Xian Zhou, Junjun Geng, Shaopeng Wu, Haobo Hou
The co-combustion of sludge (sewage and dredged sludge) with rice husk is expected to become a trend because of its economic and environmental benefits. However, the massive residues from the co-combustion process and the mobility of heavy metals (HMs) warrant special attention. The basic performance and environmental properties of the trace elements (Cr, Cu, Fe, Mn, Ba and Zn) from the co-combustion ashes were studied to promote the further utilization of these materials. These ashes have a shell particle shape, high specific area, high amorphous content and low crystalline phase content...
November 19, 2016: Chemosphere
https://www.readbyqxmd.com/read/27853207/implications-for-metal-and-volatile-cycles-from-the-ph-of-subduction-zone-fluids
#13
Matthieu E Galvez, James A D Connolly, Craig E Manning
The chemistry of aqueous fluids controls the transport and exchange-the cycles-of metals and volatile elements on Earth. Subduction zones, where oceanic plates sink into the Earth's interior, are the most important geodynamic setting for this fluid-mediated chemical exchange. Characterizing the ionic speciation and pH of fluids equilibrated with rocks at subduction zone conditions has long been a major challenge in Earth science. Here we report thermodynamic predictions of fluid-rock equilibria that tie together models of the thermal structure, mineralogy and fluid speciation of subduction zones...
November 16, 2016: Nature
https://www.readbyqxmd.com/read/27848092/estimation-and-influence-of-physicochemical-properties-and-chemical-fractions-of-surface-sediment-on-the-bioaccessibility-of-cd-and-hg-contaminant-in-langat-river-malaysia
#14
Safaa A Kadhum, Mohd Yusoff Ishak, Syaizwan Zahmir Zulkifli
This study applied the use of sequential extraction technique and simple bioaccessibility extraction test to quantify the bioavailable fractions and the human bioaccessible concentration of metals collected from nine stations in surface sediment of the Langat River. The concentrations of total and bioaccessible metals from different stations were in the range of 0.49-1.04, 0.10-0.32 μg g(-1) for T-Cd, Bio-Cd, respectively, and 12.9-128.03, 2.06-8.53 μg kg(-1) for T-Hg, Bio-Hg, respectively. The results revealed highest R-Bio-Cd in Banting station (55...
November 15, 2016: Environmental Geochemistry and Health
https://www.readbyqxmd.com/read/27847148/sulfamethazine-degradation-in-water-by-the-vuv-uv-process-kinetics-mechanism-and-antibacterial-activity-determination-based-on-a-mini-fluidic-vuv-uv-photoreaction-system
#15
Mengkai Li, Chen Wang, Miaoling Yau, James R Bolton, Zhimin Qiang
A mini-fluidic VUV/UV photoreaction system (MVPS) was developed in our previous study, and it was demonstrated as a powerful tool for studies on pollutant degradation by the VUV/UV process. In this study, we investigated the VUV/UV photodegradation of sulfamethazine (SMN), one of the most frequently detected antibiotics in the environment. The determination methods of photochemical kinetic parameters (e.g., photon fluence-based rate constant and quantum yield) were developed based on the MVPS. The photon fluence-based reaction rate constants for SMN degradation by UV alone and VUV/UV processes were determined as 0...
January 1, 2017: Water Research
https://www.readbyqxmd.com/read/27842601/the-lutzomyia-longipalpis-complex-a-brief-natural-history-of-aggregation-sex-pheromone-communication
#16
REVIEW
Carolina N Spiegel, Denise B Dos Santos Dias, Alejandra S Araki, James G C Hamilton, Reginaldo P Brazil, Théresa M Jones
In this paper we review the natural history of pheromone communication and the current diversity of aggregation-sex pheromones in the sand fly Lutzomyia longipalpis. This species complex is the main vector of Leishmania infantum, the agent of visceral leishmaniasis in the Americas. The identification of variation in pheromone chemotypes combined with molecular and sound analyses have all contributed to our understanding of the extent of divergence among cryptic members of this complex. The importance of chemical signals as pre-mating barriers and drivers of speciation is discussed...
November 14, 2016: Parasites & Vectors
https://www.readbyqxmd.com/read/27836740/comparative-transcriptome-analysis-of-chemosensory-genes-in-two-sister-leaf-beetles-provides-insights-into-chemosensory-speciation
#17
Bin Zhang, Wei Zhang, Rui-E Nie, Wen-Zhu Li, Kari A Segraves, Xing-Ke Yang, Huai-Jun Xue
Divergence in chemosensory traits has been posited as an important component of chemosensory speciation in insects. In particular, chemosensory genes expressed in the peripheral sensory neurons are likely to influence insect behaviors such as preference for food, oviposition sites, and mates. Despite their key role in insect behavior and potentially speciation, the underlying genetic basis for divergence in chemosensory traits remains largely unexplored. One way to ascertain the role of chemosensory genes in speciation is to make comparisons of these genes across closely related species to detect the genetic signatures of divergence...
November 9, 2016: Insect Biochemistry and Molecular Biology
https://www.readbyqxmd.com/read/27808432/passage-of-fiproles-and-imidacloprid-from-urban-pest-control-uses-through-wastewater-treatment-plants-in-northern-california
#18
Akash M Sadaria, Rebecca Sutton, Kelly D Moran, Jennifer Teerlink, Jackson Vanfleet Brown, Rolf U Halden
Urban pest control insecticides, specifically fipronil and its four major degradates (fipronil sulfone, sulfide, desulfinyl, and amide) and imidacloprid, were monitored during drought conditions in eight San Francisco Bay wastewater treatment plants (WWTPs). In influent and effluent, ubiquitous detections were obtained in units of ng/L for fipronil (13-88), fipronil sulfone (1-28), fipronil sulfide (1-5) and imidacloprid (58-306). In influent, 100% of imidacloprid and 62 ± 9% of total fiproles (fipronil and degradates) were present in the dissolved state, with the balance being bound to filter-removable particulates...
November 3, 2016: Environmental Toxicology and Chemistry
https://www.readbyqxmd.com/read/27808288/fast-voltammetry-of-metals-at-carbon-fiber-microelectrodes-towards-an-online-speciation-sensor
#19
Pavithra Pathirathna, Thushani Siriwardhane, Shawn P McElmurry, Stephen L Morgan, Parastoo Hashemi
Speciation controls the chemical behavior of trace metals. Thus, there is great demand for rapid speciation analysis in a variety of fields. In this study, we describe the application of fast scan cyclic voltammetry (FSCV) and fast scan adsorption controlled voltammetry (FSCAV) to trace metal speciation analysis. We show that Cu(2+) can be detected using FSCAV in different matrices. We find that matrices with different Cu(2+) binding ability do not affect the equilibrium of Cu(2+) adsorption onto CFMs, and thus are an excellent predictor for free Cu(2+) ([Cu(2+)]free) in solution...
November 3, 2016: Analyst
https://www.readbyqxmd.com/read/27807676/pm2-5-pollution-from-household-solid-fuel-burning-practices-in-central-india-2-application-of-receptor-models-for-source-apportionment
#20
Jeevan Lal Matawle, Shamsh Pervez, Manas Kanti Deb, Anjali Shrivastava, Suresh Tiwari
USEPA's UNMIX, positive matrix factorization (PMF) and effective variance-chemical mass balance (EV-CMB) receptor models were applied to chemically speciated profiles of 125 indoor PM2.5 measurements, sampled longitudinally during 2012-2013 in low-income group households of Central India which uses solid fuels for cooking practices. Three step source apportionment studies were carried out to generate more confident source characterization. Firstly, UNMIX6.0 extracted initial number of source factors, which were used to execute PMF5...
November 2, 2016: Environmental Geochemistry and Health
keyword
keyword
29344
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"