keyword
MENU ▼
Read by QxMD icon Read
search

Earth

keyword
https://www.readbyqxmd.com/read/28107947/surface-enhanced-raman-spectroscopy-sers-as-a-method-for-the-toxicological-analysis-of-synthetic-cannabinoids
#1
Thaddeus Mostowtt, Bruce McCord
Synthetic cannabinoids (K2, spice) present problems in forensic investigations because standard presumptive methods, such as immunoassays, are insufficiently specific for the wide range of potential target compounds. This issue can lead to problems with low sensitivity and yield false negative results. A potential solution to this problem is surface enhanced Raman spectroscopy (SERS). In this study we demonstrate the analysis of a set of structurally similar synthetic cannabinoids using SERS. The procedure involves mixing the analyte with gold nanoparticles prepared in a solution containing alkali or alkaline earth salt solutions...
March 1, 2017: Talanta
https://www.readbyqxmd.com/read/28107742/heavy-rare-earth-elements-affect-early-life-stages-in-paracentrotus-lividus-and-arbacia-lixula-sea-urchins
#2
Rahime Oral, Giovanni Pagano, Antonietta Siciliano, Maria Gravina, Anna Palumbo, Immacolata Castellano, Oriana Migliaccio, Philippe J Thomas, Marco Guida, Franca Tommasi, Marco Trifuoggi
BACKGROUND: Heavy rare earth elements (HREEs) have been scarcely studied for their toxicity, in spite of their applications in several technologies. Thus HREEs require timely investigations for their adverse health effects. METHODS: Paracentrotus lividus and Arbacia lixula embryos and sperm were exposed to trichloride salts of five HREEs (Dy, Ho, Er, Yb and Lu) and to Ce(III) as a light REE (LREE) reference to evaluate: 1) developmental defects (% DD) in HREE-exposed larvae or in the offspring of HREE-exposed sperm; 2) mitotic anomalies; 3) fertilization success; and 4) reactive oxygen species (ROS) formation, and nitric oxide (NO) and malondialdehyde (MDA) levels...
January 17, 2017: Environmental Research
https://www.readbyqxmd.com/read/28107476/origin-and-dispersal-history-of-two-colonial-ascidian-clades-in-the-botryllus-schlosseri-species-complex
#3
Marie L Nydam, Kirsten B Giesbrecht, Emily E Stephenson
Human-induced global warming and species introductions are rapidly altering the composition and functioning of Earth's marine ecosystems. Ascidians (Phylum Chordata, Subphylum Tunicata, Class Ascidiacea) are likely to play an increasingly greater role in marine communities. The colonial ascidian B. schlosseri is a cryptic species complex comprising five genetically divergent clades (A-E). Clade A is a global species, and Clade E has so far been identified in European waters only. Using the largest mitochondrial cytochrome oxidase I datasets yet assembled, we determine the origin and dispersal history of these species...
2017: PloS One
https://www.readbyqxmd.com/read/28107051/the-size-dependence-of-phytoplankton-growth-rates-a-trade-off-between-nutrient-uptake-and-metabolism
#4
Ben A Ward, Emilio Marañón, Boris Sauterey, Jonathan Rault, David Claessen
Rates of metabolism and population growth are often assumed to decrease universally with increasing organism size. Recent observations have shown, however, that maximum population growth rates among phytoplankton smaller than ∼6 μm in diameter tend to increase with organism size. Here we bring together observations and theory to demonstrate that the observed change in slope is attributable to a trade-off between nutrient uptake and the potential rate of internal metabolism. Specifically, we apply an established model of phytoplankton growth to explore a trade-off between the ability of cells to replenish their internal quota (which increases with size) and their ability to synthesize new biomass (which decreases with size)...
February 2017: American Naturalist
https://www.readbyqxmd.com/read/28106143/effect-of-gallium-environment-on-infrared-emission-in-er-3-doped-gallium-antimony-sulfur-glasses
#5
Qing Jiao, Ge Li, Lini Li, Changgui Lin, Guoxiang Wang, Zijun Liu, Shixun Dai, Tiefeng Xu, Qinyuan Zhang
Gallium-based Ga-Sb-S sulfide glasses was elaborated and studied. A relationship between the structure, composition, and optical properties of the glass has been established. The effects of the introduction of Ga on the structure using infrared and Raman spectroscopies and on the Er(3+)-doped IR emission have been discussed. The results show that incorporation of Ga induced the dissociation of [SbS3] pyramids units and the formation of tetrahedral [GaS4] units. The dissolved rare earth ions are separated around the Ga-S bonding and the infrared emission quenching are controlled...
January 20, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28106057/improper-electric-polarization-in-simple-perovskite-oxides-with-two-magnetic-sublattices
#6
Hong Jian Zhao, L Bellaiche, Xiang Ming Chen, Jorge Íñiguez
ABO3 perovskite oxides with magnetic A and B cations offer a unique playground to explore interactions involving two spin sublattices and the emergent effects they may drive. Of particular interest is the possibility of having magnetically driven improper ferroelectricity, as in the much studied families of rare-earth orthoferrites and orthochromites; yet, the mechanisms behind such effects remain to be understood in detail. Here we show that the strongest polar order corresponds to collinear spin configurations and is driven by non-relativistic exchange-strictive mechanisms...
January 20, 2017: Nature Communications
https://www.readbyqxmd.com/read/28104887/regional-and-global-sea-surface-temperatures-during-the-last-interglaciation
#7
Jeremy S Hoffman, Peter U Clark, Andrew C Parnell, Feng He
The last interglaciation (LIG, 129 to 116 thousand years ago) was the most recent time in Earth's history when global mean sea level was substantially higher than it is at present. However, reconstructions of LIG global temperature remain uncertain, with estimates ranging from no significant difference to nearly 2°C warmer than present-day temperatures. Here we use a network of sea-surface temperature (SST) records to reconstruct spatiotemporal variability in regional and global SSTs during the LIG. Our results indicate that peak LIG global mean annual SSTs were 0...
January 20, 2017: Science
https://www.readbyqxmd.com/read/28103294/community-based-entomological-surveillance-reveals-urban-foci-of-chagas-disease-vectors-in-sobral-state-of-cear%C3%A3-northeastern-brazil
#8
Cynara Carvalho Parente, Fernando S M Bezerra, Plutarco I Parente, Raimundo V Dias-Neto, Samanta C C Xavier, Alberto N Ramos, Filipe A Carvalho-Costa, Marli M Lima
BACKGROUND: The aim of this work was to explore the potential risk of vector-borne Chagas disease in urban districts in northeastern Brazil, by analyzing the spatiotemporal distributions and natural infection rates with Trypanosoma cruzi of triatomine species captured in recent years. The main motivation of this work was an acute human case of Chagas disease reported in 2008 in the municipality of Sobral. METHODOLOGY/PRINCIPAL FINDINGS: We analyzed data from community-based entomological surveillance carried out from 2010 to 2014...
2017: PloS One
https://www.readbyqxmd.com/read/28103108/secondary-school-students-knowledge-and-opinions-on-astrobiology-topics-and-related-social-issues
#9
Raquel Oreiro, Jordi Solbes
Astrobiology is the study of the origin of life on Earth and the distribution of life in the Universe. Its multidisciplinary approach, social and philosophical implications, and appeal within the discipline and beyond make astrobiology a uniquely qualified subject for general science education. In this study, student knowledge and opinions on astrobiology topics were investigated. Eighty-nine students in their last year of compulsory education (age 15) completed a written questionnaire that consisted of 10 open questions on the topic of astrobiology...
January 2017: Astrobiology
https://www.readbyqxmd.com/read/28103107/star-masses-and-star-planet-distances-for-earth-like-habitability
#10
David Waltham
This paper presents statistical estimates for the location and duration of habitable zones (HZs) around stars of different mass. The approach is based upon the assumption that Earth's location, and the Sun's mass, should not be highly atypical of inhabited planets. The results support climate-model-based estimates for the location of the Sun's HZ except models giving a present-day outer-edge beyond 1.64 AU. The statistical approach also demonstrates that there is a habitability issue for stars smaller than 0...
January 2017: Astrobiology
https://www.readbyqxmd.com/read/28103105/evolution-of-earth-like-extrasolar-planetary-atmospheres-assessing-the-atmospheres-and-biospheres-of-early-earth-analog-planets-with-a-coupled-atmosphere-biogeochemical-model
#11
S Gebauer, J L Grenfell, J W Stock, R Lehmann, M Godolt, P von Paris, H Rauer
Understanding the evolution of Earth and potentially habitable Earth-like worlds is essential to fathom our origin in the Universe. The search for Earth-like planets in the habitable zone and investigation of their atmospheres with climate and photochemical models is a central focus in exoplanetary science. Taking the evolution of Earth as a reference for Earth-like planets, a central scientific goal is to understand what the interactions were between atmosphere, geology, and biology on early Earth. The Great Oxidation Event in Earth's history was certainly caused by their interplay, but the origin and controlling processes of this occurrence are not well understood, the study of which will require interdisciplinary, coupled models...
January 2017: Astrobiology
https://www.readbyqxmd.com/read/28102364/indefinitely-stable-iron-iv-cage-complexes-formed-in-water-by-air-oxidation
#12
Stefania Tomyn, Sergii I Shylin, Dmytro Bykov, Vadim Ksenofontov, Elzbieta Gumienna-Kontecka, Volodymyr Bon, Igor O Fritsky
In nature, iron, the fourth most abundant element of the Earth's crust, occurs in its stable forms either as the native metal or in its compounds in the +2 or +3 (low-valent) oxidation states. High-valent iron (+4, +5, +6) compounds are not formed spontaneously at ambient conditions, and the ones obtained synthetically appear to be unstable in polar organic solvents, especially aqueous solutions, and this is what limits their studies and use. Here we describe unprecedented iron(IV) hexahydrazide clathrochelate complexes that are assembled in alkaline aqueous media from iron(III) salts, oxalodihydrazide and formaldehyde in the course of a metal-templated reaction accompanied by air oxidation...
January 19, 2017: Nature Communications
https://www.readbyqxmd.com/read/28101543/the-recent-development-of-efficient-earth-abundant-transition-metal-nanocatalysts
#13
REVIEW
Dong Wang, Didier Astruc
Whereas noble metal compounds have long been central in catalysis, Earth-abundant metal-based catalysts have in the same time remained undeveloped. Yet the efficacy of Earth-abundant metal catalysts was already shown at the very beginning of the 20th century with the Fe-catalyzed Haber-Bosch process of ammonia synthesis and later in the Fischer-Tropsch reaction. Nanoscience has revolutionized the world of catalysis since it was observed that very small Au nanoparticles (NPs) and other noble metal NPs are extraordinarily efficient...
January 19, 2017: Chemical Society Reviews
https://www.readbyqxmd.com/read/28100818/lowland-biotic-attrition-revisited-body-size-and-variation-among-climate-change-winners-and-losers
#14
Jedediah F Brodie, Matthew Strimas-Mackey, Jayasilan Mohd-Azlan, Alys Granados, Henry Bernard, Anthony J Giordano, Olga E Helmy
The responses of lowland tropical communities to climate change will critically influence global biodiversity but remain poorly understood. If species in these systems are unable to tolerate warming, the communities-currently the most diverse on Earth-may become depauperate ('biotic attrition'). In response to temperature changes, animals can adjust their distribution in space or their activity in time, but these two components of the niche are seldom considered together. We assessed the spatio-temporal niches of rainforest mammal species in Borneo across gradients in elevation and temperature...
January 25, 2017: Proceedings. Biological Sciences
https://www.readbyqxmd.com/read/28100493/large-14c-excursion-in-5480-bc-indicates-an-abnormal-sun-in-the-mid-holocene
#15
Fusa Miyake, A J Timothy Jull, Irina P Panyushkina, Lukas Wacker, Matthew Salzer, Christopher H Baisan, Todd Lange, Richard Cruz, Kimiaki Masuda, Toshio Nakamura
Radiocarbon content in tree rings can be an excellent proxy of the past incoming cosmic ray intensities to Earth. Although such past cosmic ray variations have been studied by measurements of (14)C contents in tree rings with ≥10-y time resolution for the Holocene, there are few annual (14)C data. There is a little understanding about annual (14)C variations in the past, with the exception of a few periods including the AD 774-775 (14)C excursion where annual measurements have been performed. Here, we report the result of (14)C measurements using the bristlecone pine tree rings for the period from 5490 BC to 5411 BC with 1- to 2-y resolution, and a finding of an extraordinarily large (14)C increase (20‰) from 5481 BC to 5471 BC (the 5480 BC event)...
January 18, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28099815/stocks-flows-and-distribution-of-critical-metals-in-embedded-electronics-in-passenger-vehicles
#16
Eliette Restrepo, Amund N Løvik, Patrick Wäger, Rolf Widmer, Radek Lonka, Daniel B Müller
One of the major applications of critical metals (CMs) is in electrical and electronic equipment (EEE), which is increasingly embedded in other products, notably passenger vehicles. However, recycling strategies for future CM quantities in end-of-life vehicles (ELVs) are poorly understood, mainly due to a limited understating of the complexity of automotive embedded EEE. We introduce a harmonization of the network structure of automotive electronics that enables a comprehensive quantification of CMs in all embedded EEE in a vehicle...
January 18, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28099025/optical-line-width-broadening-mechanisms-at-the-10-khz-level-in-eu-3-y2o3-nanoparticles
#17
John G Bartholomew, Karmel de Oliveira Lima, Alban Ferrier, Philippe Goldner
We identify the physical mechanisms responsible for the optical homogeneous broadening in Eu(3+):Y2O3 nanoparticles to determine whether rare-earth crystals can be miniaturized to volumes less than λ(3) while preserving their appeal for quantum technology hardware. By studying how the homogeneous line width depends on temperature, applied magnetic field, and measurement time scale, the dominant broadening interactions for various temperature ranges above 3 K were characterized. Below 3 K the homogeneous line width is dominated by an interaction not observed in bulk crystal studies...
January 18, 2017: Nano Letters
https://www.readbyqxmd.com/read/28098994/hydrides-of-alkaline-earth-tetrel-aett-zintl-phases-covalent-tt-h-bonds-from-silicon-to-tin
#18
Henry Auer, Robin Guehne, Marko Bertmer, Sebastian Weber, Patrick Wenderoth, Thomas Christian Hansen, Jürgen Haase, Holger Kohlmann
Zintl phases form hydrides either by incorporating hydride anions (interstitial hydrides) or by covalent bonding of H to the polyanion (polyanionic hydrides), which yields a variety of different compositions and bonding situations. Hydrides (deuterides) of SrGe, BaSi, and BaSn were prepared by hydrogenation (deuteration) of the CrB-type Zintl phases AeTt and characterized by laboratory X-ray, synchrotron, and neutron diffraction, NMR spectroscopy, and quantum-chemical calculations. SrGeD4/3-x and BaSnD4/3-x show condensed boatlike six-membered rings of Tt atoms, formed by joining three of the zigzag chains contained in the Zintl phase...
January 18, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28098993/in-situ-hydrogenation-of-the-zintl-phase-srge
#19
Henry Auer, Dirk Wallacher, Thomas Christian Hansen, Holger Kohlmann
Hydrides (deuterides) of the CrB-type Zintl phases AeTt (Ae = alkaline earth; Tt = tetrel) show interesting bonding properties with novel polyanions. In SrGeD4/3-x (γ phase), three zigzag chains of Ge atoms are condensed and terminated by covalently bound D atoms. A combination of in situ techniques (thermal analysis and synchrotron and neutron powder diffraction) revealed the existence of two further hydride (deuteride) phases with lower H (D) content (called α and β phases). Both are structurally related to the parent Zintl phase SrGe and to the ZrNiH structure type containing variable amounts of H (D) in Sr4 tetrahedra...
January 18, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28098332/revisiting-the-optimized-doping-ratio-in-core-shell-nanostructured-upconversion-particles
#20
Bin Shen, Shengming Cheng, Yuyang Gu, Danrui Ni, Yilin Gao, Qianqian Su, Wei Feng, Fuyou Li
The development of rare-earth doped upconversion nanoparticles (RE-UCNPs) in various applications is fuelling the demand for nanoparticles with highly enhanced upconversion luminescence (UCL). Although the core/shell structure is proved to enhance the UCL effectively, there is still plenty of room to further improve the UCL by optimizing the doping ratio of the materials. In this article, a general strategy is demonstrated to achieve highly-enhanced visible UCL in core/shell nanostructured NaREF4 by increasing the doping ratio of Yb(3+) in the core region...
January 18, 2017: Nanoscale
keyword
keyword
113758
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"