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At least 487 records · Page 27

A method to load tellurium in liquid scintillator for the study of neutrinoless double beta decay

Herein, a method has been developed to load tellurium into liquid scintillator so as to permit searches for neutrinoless double beta decay with high sensitivity. The approach involves the synthesis of an oil-soluble tellurium compound from telluric acid and an organic diol. The process utilises distillable chemicals that can be safely handled underground and affords low radioactive backgrounds, low optical absorption and high light yields at loading levels of at least several percent Te by weight.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

New directions and principles for solvent extraction for recovery of lithium from aqueous brines and mineral leachates: A brief review

Increasing demand for lithium for manufacturing of batteries is fueling the unprecedented search for improved recovery and alternative sources. Wider source distribution, lower energy consumption, and greater sustainability make extraction of lithium from brines, both natural and process-derived, an attractive alternative to mineral ores. Solvent extraction, used industrially for production of metals, salts, and pharmaceuticals, has been investigated as a methodology for lithium recovery for several decades. However, industrial application of solvent extraction for lithium recovery has so far been limited. In contrast, direct lithium extraction using adsorbents based on inorganic minerals has rapidly advanced from research to commercialization. A comparison of solvent extraction processes to adsorption highlights these issues and explains the preference for adsorbents. Although the application of solvent extraction has been criticized for use of large amounts of acid, alkali, and organic solvents, steady progress has been made to improve its potential for industrial lithium production, spurred on generally by the advantages of solvent extraction in selectivity and throughput. Previously developed beta-diketone, organophosphate, and crown ether ligands are being adapted and improved. Their novel use with ionic liquids, deep eutectic solvents, and membrane technologies promises to expand capabilities for extraction of lithium from dilute aqueous sources while improving sustainability. Possibilities for further discovery and innovation abound. In this review, we provide a unique perspective from the field of solvent extraction starting with fundamentals such as ion-transfer theory and apply them to understanding lithium selectivity and extraction behavior. In conclusion, the results are cast in the light of the practical realities of developing economical solvent extraction processes.

Brine↗

Transcriptional, metabolic, physiological and developmental responses of switchgrass to phosphorus limitation

Abstract Knowing how switchgrass ( Panicum virgatum L . ) responds and adapts to phosphorus (P)‐limitation will aid efforts to optimize P acquisition and use in this species for sustainable biomass production. This integrative study investigated the impacts of mild, moderate, and severe P‐stress on genome transcription and whole‐plant metabolism, physiology and development in switchgrass. P‐limitation reduced overall plant growth, increased root/shoot ratio, increased root branching at moderate P‐stress, and decreased root diameter with increased density and length of root hairs at severe P‐stress. RNA‐seq analysis revealed thousands of genes that were differentially expressed under moderate and severe P‐stress in roots and/or shoots compared to P‐replete plants, with many stress‐induced genes involved in transcriptional and other forms of regulation, primary and secondary metabolism, transport, and other processes involved in P‐acquisition and homeostasis. Amongst the latter were multiple miRNA399 genes and putative targets of these. Metabolite profiling showed that levels of most sugars and sugar alcohols decreased with increasing P stress, while organic and amino acids increased under mild and moderate P‐stress in shoots and roots, although this trend reversed under severe P‐stress, especially in shoots.

59 BASIC BIOLOGICAL SCIENCES↗

Aircraft measurements of aerosol and trace gas chemistry in the eastern North Atlantic

The Aerosol and Cloud Experiment in the Eastern North Atlantic (ACE-ENA) investigated properties of aerosols and subtropical marine boundary layer (MBL) clouds. Low subtropical marine clouds can have a large effect on Earth's radiative budget, but they are poorly represented in global climate models. In order to understand their radiative effects, it is imperative to understand the composition and sources of the MBL cloud condensation nuclei (CCN). The campaign consisted of two intensive operation periods (IOPs) (June–July 2017 and January–February 2018) during which an instrumented G-1 aircraft was deployed from Lajes Field on Terceira Island in the Azores, Portugal. The G-1 conducted research flights in the vicinity of the Atmospheric Radiation Measurement (ARM) Eastern North Atlantic (ENA) atmospheric observatory on Graciosa Island. An Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) and Ionicon proton-transfer-reaction mass spectrometer (PTR-MS) were deployed aboard the aircraft, characterizing chemistry of non-refractory aerosol and trace gases, respectively. The eastern North Atlantic region was found to be very clean, with an average non-refractory submicrometer aerosol mass loading of 0.6 µg m −3 in the summer and 0.1 µg m −3 in the winter, measured by the AMS. Average concentrations of the trace reactive gases methanol and acetone were 1–2 ppb; benzene, toluene and isoprene were even lower, <1 ppb. Mass fractions of sulfate, organics, ammonium and nitrate in the boundary layer were 69 %, 23 %, 7 % and 1 % and remained largely similar between seasons. The aerosol chemical composition was dominated by sulfate and highly processed organics. Particulate methanesulfonic acid (MSA), a well-known secondary biogenic marine species, was detected, with an average boundary layer concentration of 0.021 µg m −3 , along with its gas-phase precursor, dimethyl sulfide (DMS). MSA accounted for no more than 3 % of the submicron, non-refractory aerosol in the boundary layer. Examination of vertical profiles of aerosol and gas chemistry during ACE-ENA reveals an interplay of local marine emissions and long-range-transported aged aerosol. A case of transport of biomass burning emissions from North American fires has been identified using back-trajectory analysis. In the summer, the non-refractory portion of the background CCN budget was heavily influenced by aerosol associated with ocean productivity, in particular sulfate formed from DMS oxidation. Episodic transport from the continents, particularly of biomass burning aerosol, periodically increased CCN concentrations in the free troposphere. In the winter, with ocean productivity lower, CCN concentrations were overall much lower and dominated by remote transport. These results show that anthropogenic emissions perturb CCN concentrations in remote regions that are sensitive to changes in CCN number and illustrate that accurate predictions of both transport and regional aerosol formation from the oceans are critical to accurately modeling clouds in these regions.

54 ENVIRONMENTAL SCIENCES↗

Silazane elastomer remains resilient at 400 deg C

Smooth, unfoamed elastomer is unaffected by common acids, alkalies, and organic solvents. Its thermal stability, chemical resistance, and physical properties make it of interest for various applications.

Source record↗

Could life originate now?

Abiogenesis, discussing hydrogen, oxygen, carbon, nitrogen and sulfur conversion into amino acids for simple organic compounds formation

Fox, S. W.↗

Organic compounds in the Murchison meteorite.

Impressive supporting evidence for the concept of the chemical evolution of life has appeared in the discovery of biologically important compounds in extraterrestrial samples. The approaches pursued to detect extraterrestrial organic compounds include the study of interstellar space by radioastronomy, the evaluation of the Apollo lunar samples, and the analysis of meteorites, both ancient and recent. It has been found that the clouds of gas in the interstellar medium contain a wide variety of molecules, most of which are organic in nature. The carbonaceous chondrites contain polymeric organic matter. Amino acids have been detected in the Murchison meteorite.

Ponnamperuma, C.↗

Polyimide foam for the thermal insulation and fire protection

The preparation of chemically resistant and flame retardant foams from polyfunctional aromatic carboxylic acid derivatives and organic polyisocyanates is outlined. It was found that polyimide foams of reproducible density above 1 lb./ft. and below 6 lbs./cu ft. can be obtained by employing in the reaction of least 2% by weight of siloxane-glycol copolymer as a surfactant which acts as a specific density control agent. Polyimide foams into which reinforcing fibers such as silicon dioxide and carbon fibers may be incorporated were also produced.

Rosser, R. W.↗

Recent work in advanced hydrogen production concepts

The hydrogen photoelectrolytic conversion activity investigated the practicability of semiconductor electrolytic devises that use solar energy to decompose water into hydrogen and oxygen in an apparent single step process. The photocatalytic decomposition of inorganic hydrogen compounds; i.e., hydrobromic and hydriodic acids using rhodium organic bridge complexes were also studied. The feasibility of direct high temperature thermal decompositions of water with diffusion processes for separation of the equilibrium mixture of hydrogen and oxygen into usable energy sources was examined.

Lawson, D. D.↗

Photochemical synthesis of biomolecules under anoxic conditions

The long-wavelength UV anoxic photosynthesis of uracil, various sugars (including deoxyribose and glycoaldehyde), amino acids, and other organic photoproducts is reported. The reactions were conducted in a mixture of water, calcium carbonate, hydrazine, and formaldehyde which were subjected to 24 hr or 72 hr radiation. Product yields were greatest when the hydrazine/formaldehyde ratio was one, and when the reactant concentrations were low. These data suggest that organic products can be formed in variety from those amounts of formaldehyde and hydazine precursors which are themselves formed under anoxic UV photochemical conditions.

Folsome, C.↗

Gas stream purifier

A gas stream purifier has been developed that is capable of removing corrosive acid, base, solvent, organic, inorganic, and water vapors as well as particulates from an inert mixed gas stream using only solid scrubbing agents. This small, lightweight purifier has demonstrated the ability to remove contaminants from an inert gas stream with a greater than 99 percent removal efficiency. The Gas Stream Purifier has outstanding market and sales potential in manufacturing, laboratory and science industries, medical, automotive, or any commercial industry where pollution, contamination, or gas stream purification is a concern. The purifier was developed under NASA contract NAS9-18200 Schedule A for use in the international Space Station. A patent application for the Gas Stream Purifier is currently on file with the United States Patent and Trademark Office.

Adam, Steven J.↗

BOREAS TE-1 SSA Soil Lab Data

This data set was collected by TE-1 to provide a set of soil properties for BOREAS investigators in the SSA. The soil samples were collected at sets of soil pits in 1993 and 1994. Each set of soil pits was in the vicinity of one of the five flux towers in the BOREAS SSA. The collected soil samples were sent to a lab, where the major soil properties were determined. These properties include, but are not limited to, soil horizon; dry soil color; pH; bulk density; total, organic, and inorganic carbon; electric conductivity; cation exchange capacity; exchangeable sodium, potassium, calcium, magnesium, and hydrogen; water content at 0.01, 0.033, and 1.5 MPascals; nitrogen; phosphorus; particle size distribution; texture; pH of the mineral soil and of the organic soil; extractable acid; and sulfur. The data are stored in tabular ASCII text files. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

Hall, Forrest G.↗

BOREAS TE-2 NSA Soil Lab Data

This data set contains the major soil properties of soil samples collected in 1994 at the tower flux sites in the Northern Study Area (NSA). The soil samples were collected by Hugo Veldhuis and his staff from the University of Manitoba. The mineral soil samples were largely analyzed by Barry Goetz, under the supervision of Dr. Harold Rostad at the University of Saskatchewan. The organic soil samples were largely analyzed by Peter Haluschak, under the supervision of Hugo Veldhuis at the Centre for Land and Biological Resources Research in Winnipeg, Manitoba. During the course of field investigation and mapping, selected surface and subsurface soil samples were collected for laboratory analysis. These samples were used as benchmark references for specific soil attributes in general soil characterization. Detailed soil sampling, description, and laboratory analysis were performed on selected modal soils to provide examples of common soil physical and chemical characteristics in the study area. The soil properties that were determined include soil horizon; dry soil color; pH; bulk density; total, organic, and inorganic carbon; electric conductivity; cation exchange capacity; exchangeable sodium, potassium, calcium, magnesium, and hydrogen; water content at 0.01, 0.033, and 1.5 MPascals; nitrogen; phosphorus: particle size distribution; texture; pH of the mineral soil and of the organic soil; extractable acid; and sulfur. These data are stored in ASCII text files. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

Veldhuis, Hugo↗

Anaerovirgula multivorans gen. nov., sp. nov., a Novel Spore-Forming, Alkaliphilic Anaerobe Isolated from Owens Lake, California, USA

A novel, alkaliphilic, obligately anaerobic bacterium, strain SCAT, was isolated from mud sediments of a soda lake in California, USA. The rod-shaped cells were motile, Gram-positive, formed spores and were 0.4-0.5x2.5-5.0 micrometers in size. Growth occurred within the pH range 6.7-10.0 and was optimal at pH 8.5. The temperature range for growth was 10-45 degrees C, with optimal growth at 35 degrees C. NaCl was required for growth. Growth occurred at 0.5-9.0% (w/v) NaCl and was optimal at 1-2% (w/v). The novel isolate was a catalase-negative chemo-organoheterotroph that fermented sugars, proteolysis products, some organic and amino acids, glycerol, d-cellobiose and cellulose. It was also capable of growth by the Stickland reaction. Strain SCAT was sensitive to tetracycline, chloramphenicol, rifampicin and gentamicin, but it was resistant to ampicillin and kanamycin. The G+C content of the genomic DNA was 34.2 mol%. Major fatty acid components were C14:0, iso-C15:0, C16:1omega9c and C16:0. 16S rRNA gene sequence analysis of strain SCAT showed a similarity of approximately 97% with the type strains of Clostridium formicaceticum and Clostridium aceticum in clostridial cluster XI and a similarity of less than 94.2% to any other recognized Clostridium species and those of related genera in this cluster. Strain SCAT was clearly differentiated from C. formicaceticum and C. aceticum based on comparison of their phenotypic properties and fatty acid profiles, as well as low levels of DNA-DNA relatedness between strain SCAT and the type strains of these two species. Therefore, strain SCAT is considered to represent a novel species of a new genus, Anaerovirgula multivorans gen. nov., sp. nov., in clostridial cluster XI. The type strain is SCAT (=ATCC BAA-1084T=JCM 12857T=DSM 17722T=CIP 107910T).

Pikuta, Elena V.↗

Correlating Mineralogy and Amino Acid Contents of Milligram-Scale Murchison Carbonaceous Chondrite Samples

Amino acids, the building blocks of proteins, have been found to be indigenous in most of the carbonaceous chondrite groups. The abundances of amino acids, as well as their structural, enantiomeric and isotopic compositions differ significantly among meteorites of different groups and petrologic types. This suggests that there is a link between parent-body conditions, mineralogy and the synthesis and preservation of amino acids (and likely other organic molecules). However, elucidating specific causes for the observed differences in amino acid composition has proven extremely challenging because samples analyzed for amino acids are typically much larger ((is) approximately 100 mg powders) than the scale at which meteorite heterogeneity is observed (sub mm-scale differences, (is) approximately 1-mg or smaller samples). Thus, the effects of differences in mineralogy on amino acid abundances could not be easily discerned. Recent advances in the sensitivity of instrumentation have made possible the analysis of smaller samples for amino acids, enabling a new approach to investigate the link between mineralogical con-text and amino acid compositions/abundances in meteorites. Through coordinated mineral separation, mineral characterization and highly sensitive amino acid analyses, we have performed preliminary investigations into the relationship between meteorite mineralogy and amino acid composition. By linking amino acid data to mineralogy, we have started to identify amino acid-bearing mineral phases in different carbonaceous meteorites. The methodology and results of analyses performed on the Murchison meteorite are presented here.

Burton, Aaron, S.↗

Indigenous Aliphatic Amines in the Aqueously Altered Orgueil Meteorite

The CI1 Orgueil meteorite is a highly aqueously altered carbonaceous chondrite. Ithas been extensively studied, and despite its extensive degree of aqueous alteration andsome documented instances of contamination, several indigenous organic compoundsincluding amino acids, carboxylic acids, and nucleobases have been detected in its carbon-rich matrix. We recently developed a novel gas chromatographic method for theenantiomeric and compound-specific isotopic analyses of meteoritic aliphatic monoamines inextracts and have now applied this method to investigate the monoamine content inOrgueil. We detected 12 amines in Orgueil, with concentrations ranging from 1.1 to332 nmol g1of meteorite and compared this amine content in Orgueil with that of theCM2 Murchison meteorite, which experienced less parent-body aqueous alteration.Methylamine is four times more abundant in Orgueil than in Murchison. As with otherspecies, the amine content in Orgueil extracts shows less structural diversity than that inMurchison extracts. We measured the compound-specific stable carbon isotopic ratios(d13C) for 5 of the 12 monoamines detected in Orgueil and found a range ofd13C valuesfrom–20 to+59&. Thesed13C values fall into the range of other meteoritic organiccompounds, although they are13C-depleted relative to their counterparts extracted from theMurchison meteorite. In addition, we measured the enantiomeric composition for the chiralmonoamines (R)- and (S)-sec-butylamine in Orgueil, and found it was racemic withinexperimental error, in contrast with theL-enantiomeric excess found for its amino acidstructural analog isovaline. The racemic nature ofsec-butylamine in Orgueil wascomparable to that previously observed in Murchison, and to other CM2 and CR2carbonaceous chondrites measured in this work (ALH 83100 [CM1/2], LON 94101 [CM2],LEW 90500 [CM2], LAP 02342 [CR2], and GRA 95229 [CR2]). These results allow us toplace some constraints on the effects of aqueous alteration observed over the monoamineconcentrations in Orgueil and Murchison, and to evaluate the primordial syntheticrelationships between meteoritic monoamines and amino acids.

Jose C Aponte↗