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1

Integrated cation–anion\\/volatile fluid inclusion analysis by gas and ion chromatography; methodology and examples  

Microsoft Academic Search

Combined gas and ion chromatographic analysis of well characterized, small (?1 g) fluid inclusion-bearing samples is a powerful, but simple, means for obtaining integrated fluid concentrations of major and trace, volatile and ionic fluid constituents without using microthermometrically determined salinity for normalization. The methodology, which is described and assessed in detail, involves crushing a carefully cleaned sample at ?105°C in

D. M. DeR Channer; C. J Bray; E. T. C Spooner

1999-01-01

2

Major sources of exposure to benzene and other volatile organic chemicals  

Microsoft Academic Search

The major sources of human exposure to about a dozen volatile organic chemicals (VOCs) have recently been identified. For nearly every chemical, the major sources of exposure are completely different from the major sources of emissions. This finding implies that current environmental regulations and control strategies are misdirected. Important sources of exposure are typically not regulated in any way, whereas

Lance Wallace

1990-01-01

3

Ion mobility spectrometry for detection of skin volatiles  

PubMed Central

Volatile organic compounds (VOCs) released by humans through their skin were investigated in near real time using ion mobility spectrometry after gas chromatographic separation with a short multi-capillary column. VOCs typically found in a small nitrogen flow covering the skin are 3-methyl-2-butenal, 6-methylhept-5-en-2-one, sec-butyl acetate, benzaldehyde, octanal, 2-ethylhexanol, nonanal and decanal at volume fractions in the low part per billion-(ppb) range. The technique presented here may contribute to elucidating some physiological processes occurring in the human skin. PMID:23217311

Ruzsanyi, Veronika; Mochalski, Pawel; Schmid, Alex; Wiesenhofer, Helmut; Klieber, Martin; Hinterhuber, Hartmann; Amann, Anton

2012-01-01

4

Majority ion heating near the ion-ion hybrid layer in tokamaks  

SciTech Connect

Efficient direct majority ion heating in a deuterium-tritium (D-T) reactor-grade plasma via absorption of fast magnetosonic waves in the ion cyclotron range of frequencies (ICRF) is discussed. Majority ion heating results from resonance overlap between the cyclotron layers and the D-T ion-ion hybrid layer in hot, dense plasmas for fast waves launched with high parallel wavenumbers. Analytic and numerical models are used to explore the regime in ITER plasmas.

Phillips, C.K.; Hosea, J.C.; Ignat, D.; Majeski, R.; Rogers, J.H.; Schilling, G.; Wilson, J.R.

1995-08-01

5

Effect of packaging materials and storage on major volatile compounds in three Australian native herbs.  

PubMed

Lemon myrtle, anise myrtle, and Tasmanian pepper leaf are commercial Australian native herbs with a high volatile or essential oil content. Packaging of the herbs in high- or low-density polyethylene (HDPE and LDPE) has proven to be ineffective in preventing a significant loss of volatile components on storage. This study investigates and compares the effectiveness of alternate high-barrier property packaging materials, namely, polyvinylidene chloride coated polyethylene terephthalate/casted polypropylene (PVDC coated PET/CPP) and polyethylene terephthalate/polyethylene terephthalate/aluminum foil/linear low-density polyethylene (PET/PET/Foil/LLDPE), in prevention of volatile compound loss from the three native herbs stored at ambient temperature for 6 months. Concentrations of major volatiles were monitored using gas chromatography-mass spectrometry (GC-MS) techniques. After 6 months of storage, the greatest loss of volatiles from lemon myrtle was observed in traditional LDPE packaging (87% loss) followed by storage in PVDC coated PET/CPP (58% loss) and PET/PET/Foil/LLDPE (loss of 23%). The volatile loss from anise myrtle and Tasmanian pepper leaf stored in PVDC coated PET/CPP and PET/PET/Foil/LLDPE packaging was <30%. This study clearly indicates the importance of selecting the correct packaging material to retain the quality of herbs with high volatile content. PMID:23682630

Chaliha, Mridusmita; Cusack, Andrew; Currie, Margaret; Sultanbawa, Yasmina; Smyth, Heather

2013-06-19

6

Chemical composition of major ions in rainwater.  

PubMed

The present study investigated the chemical composition of rainwater at Kabir nagar, Nari, Nagpur, Maharashtra, India. The rainwater samples were collected on event basis during June-July-August-2006 and were analyzed for pH, major anions Cl, NO(3), SO(4)) and cations (Ca, Mg, Na, K, NH4). The pH value varied from 6.0 to 7.3 (avg. 6.3 +/- 0.3) indicating alkaline nature of rainwater. The pH of the rainwater was found well above the reference pH (5.6), showing alkalinity during the monsoon season. The average and standard deviation of ionic composition was found to be 98.1 +/- 10.6 micro eql(-1). The total anions contribute 45.1% and cations 54.9%, respectively to rainwater. Neutralization factors (NF) followed a sequence of NF(Ca) > NF(Mg) > NF(NH4) with factors of 1.1, 0.38 and 0.15 indicating the crustal components are responsible for neutralization of anions. The average ratio of (NO(3) + Cl)/SO(4) observed as 1.1 indicates that nitric and hydrochloric acid influences the acidity of rainwater. The ratio of NH(4)/NO(3) and NH(4)/SO(4) was observed as 0.68 and 0.34 indicate that the possible compounds which may predominate in the atmosphere are NH(4)NO(3) and (NH(4))(2)SO(4). Ionic correlation was established to identify sources of origin. A good correlation was seen between Ca and Mg (r = 0.95); suggesting the common occurrence of these ions from crustal origin. Similarly, the acidic ions SO(4) and NO(3) correlated well (r = 0.60) indicating their origin from similar sources. Other relatively significant correlations were observed between Ca and SO4 (r = 0.92), Mg and SO(4) (r = 0.83), Ca and NO(3) (r = 0.09), Ca and Cl (r = 0.34) and Mg and Cl (r = 0.31), and Mg and NO(3) (r = 0.71). The observed rainwater ratio of Cl/Na (1.1) is closer to that of seawater ratio (1.16) indicates fractionation of sea-salt and modifications by non-marine constituents as the site is 834 km away from the sea coast. The nss-Ca contribution was observed as 95.7% suggesting their crustal origin whereas nss-Mg and nss-K shows their contribution as 87.9% and 83.2% indicating influence of soil sources. The nss-SO(4) contributed as 87.4% shows anthropogenic origin. PMID:18196188

Salve, P R; Maurya, A; Wate, S R; Devotta, Sukumar

2008-03-01

7

Assessment of ambient volatile organic compounds (VOCs) near major roads in urban Nanjing, China  

NASA Astrophysics Data System (ADS)

Volatile organic compounds (VOCs) are a major component of atmospheric pollutants in Nanjing, a large city in the east of China. Accordingly, 12-h diurnal monitoring for ten consecutive days was performed adjacent to major roads in five districts, ca.1.5 m above ground level, in April, July and October 2006, and January 2007. The most numerous species of VOCs (benzene, toluene, ethylbenzene, m/ p-xylene, o-xylene, 1,2,4-trimethylbenzene, 1,3,5-trimethylbenzene, tetrachloromethane, trichloroethane and tetrachloroethane) were selected as the target pollutants for this field study of atmospheric distribution. The eleven VOCs were mostly found in gas phase due to their high vapor pressures. Gas-phase concentrations ranged between 0.6 and 67.9 ?g m - 3 . Simultaneously, the levels of those VOCs measured near major roads were associated slightly with their regional background level. For all these areas, as expected, the high traffic area was the highest in terms of concentration. A positive correlation was also found between the VOC levels and traffic density. Our studies also provided VOC distribution, and vertical/horizontal profiles. The results show that traffic-related exposure to VOCs in major road microenvironments is higher than elsewhere and poses a potential threat to pedestrians, commuters, and traffic-exposed workers.

Wang, P.; Zhao, W.

2008-08-01

8

Determination of volatile biogenic amines in muscle food products by ion mobility spectrometry  

Microsoft Academic Search

The extent of spoilage of muscle food products was determined through measurement of volatile biogenic amines that emanated from food samples. The release of the amines was enhanced by addition of a few drops of an alkaline solution and the amines were monitored by ion mobility spectrometry (IMS). The limit of detection of the method for trimethylamine (TMA) was 2ng

Zeev Karpas; Boris Tilman; Rachel Gdalevsky; Avraham Lorber

2002-01-01

9

A volatile organic analyzer for Space Station: Description and evaluation of a gas chromatography/ ion mobility  

NASA Technical Reports Server (NTRS)

A Volatile Organic Analyzer (VOA) is being developed as an essential component of the Space Station's Environmental Health System (EHS) air quality monitoring strategy to provide warning to the crew and ground personnel if volatile organic compounds exceed established exposure limits. The short duration of most Shuttle flights and the relative simplicity of the contaminant removal mechanism have lessened the concern about crew exposure to air contaminants on the Shuttle. However, the longer missions associated with the Space Station, the complex air revitalization system and the proposed number of experiments have led to a desire for real-time monitoring of the contaminants in the Space Station atmosphere. Achieving the performance requirements established for the VOA within the Space Station resource (e.g., power, weight) allocations led to a novel approach that joined a gas chromatograph (GC) to an ion mobility spectrometer (IMS). The authors of this paper will discuss the rational for selecting the GC/IMS technology as opposed to the more established gas chromatography/mass spectrometry (GC/MS) for the foundation of the VOA. The data presented from preliminary evaluations will demonstrate the versatile capability of the GC/IMS to analyze the major contaminants expected in the Space Station atmosphere. The favorable GC/IMS characteristics illustrated in this paper included excellent sensitivity, dual-mode operation for selective detection, and mobility drift times to distinguish co-eluting GC peaks. Preliminary studies have shown that the GC/IMS technology can meet surpass the performance requirements of the Space Station VOA.

Limero, Thomas F.; James, John T.

1994-01-01

10

Temporal variation of volatile organic compounds and their major emission sources in Seoul, Korea.  

PubMed

This study examines the characteristics of volatile organic compounds (VOCs) and their major emission sources at the Bulgwang site in Seoul, Korea. The annual levels of VOCs (96.2-121.1 ppb C) have shown a decreasing trend from 2004 to 2008. The most abundant component in Seoul was toluene, which accounted for over 23.5 % of the total VOCs on the parts per billion on a carbon basis, and the portions of alkanes with two to six carbons constituted the largest major lumped group, ranging from 40.1 to 48.4 % (45.3 ± 3.7 %) of the total VOCs. Major components of the solvent (toluene, m/p-xylene, o-xylene, and ethylbenzene) showed high in daytime and summer and low in nighttime and winter due mainly to the variation of the ambient temperature. The species mostly emitted from gasoline vapor (i/n-butane, i/n-pentane, n-hexane, and 2-methylpentane) and vehicular exhaust (ethylene, acetylene, and benzene) showed bimodal peaks in the diurnal variation around the commuting hours because of the high traffic volume. For the 14 out of 15 highest concentration species, the weekend effect was only evident on Sundays because of the stepwise implementation of the 5-day work-week system. Principal components analysis (PCA) was applied in order to identify the sources of the 15 highest concentration VOCs and, as a result, three principal components such as gasoline vapor (48.9 %), vehicular exhaust (17.9 %), and evaporation of solvents (9.8 %) were obtained to explain a total of 76.6 % of the data variance. Most influential contributing sources at the sampling site were traffic-related ones although the use of solvent was the dominant emission source based on the official emission inventory. PMID:23728967

Shin, H J; Roh, S A; Kim, J C; Lee, S J; Kim, Y P

2013-12-01

11

Volatile Emissions from Subduction-related Volcanoes: Major and Trace Elements  

NASA Astrophysics Data System (ADS)

Present-day volatile emissions associated with subduction zone volcanism can be estimated in two ways. One approach is to assume magma production rate at arcs is 20% that of MOR and scale to the MOR 3He flux (1000 mol/yr) to obtain a mantle-derived arc He-3 flux of 200+/-40 mol/yr. This flux and measured gas ratios (xI/3He where xI is the gas species of interest) obtained from volcanic and hydrothermal samples is then used to calculate volatile emissions. A global arc CO2 flux of 0.3 to 3.1 x 1012 mol/yr has been obtained in this way. Another approach is to use individual arc volcano SO2 fluxes (determined by remote sensing) in combination with CO2/SO2 ratios of high temperature fumaroles to calculate volcanic CO2 fluxes. Integrating over an individual arc, and using a power-law distribution to include non-measured volcanoes, it is possible to produce a volatile flux estimate for a particular arc. Summing over all arcs allows a global estimate (e.g. ˜ 1.6 x1012 mol/yr for arc CO2). There are caveats with both methods. In the former case, it is assumed that the mantle wedge is characterized by a similar 3He content to MORB-source. In the latter case, the distribution of SO2 fluxes is decidedly uneven necessitating poorly-justified extrapolations. For example, there is little data available from the I-B-M, Lesser Antilles and Philippines whereas Central American volcanoes have numerous published SO2 fluxes. A further issue (in addition to geographical bias), is the absence of volatile fluxes from submarine arcs. Despite these problems, global estimates of SO2 and CO2 fluxes by both methods vary by only one order of magnitude [1]. It is emphasized that these are present-day estimates as paleo-degassing rates of arc magmas are poorly constrained and depend entirely on estimates of magma intrusion and extrusion rates [2]. The same approach has been used for other species although the flux of magmatic N2, H2O, HCl, HF from arcs remains poorly constrained (N2: ˜ 6 x108 to 2 x1010 mol/yr; H2O: ˜ 8 x1012 mol/yr; HCl ˜1 x1010 to 4x1011 mol/yr, HF: ˜3 x109 to 3 x1011 mol/yr)[1,3]. Due to the preferential partitioning of HCl and HF into volcano hosted hydrothermal systems, fluxes from magma bodies are probably much larger than what is emitted into the atmosphere. Trace element emissions from subduction related volcanoes are also poorly constrained but are potentially significant. High temperature (>700C) volcanic gas samples show that concentrations of Be, Rb, Sr, Ru, Rh, Pd, Cd, W, Re, Pt, Pb, Bi, Se, Sc are in the 5 to 1300 ug/L range and up to 25000 ug/L of B have been measured [4,5]. Using these concentrations and the global arc SO2 flux gives estimates of trace element fluxes on the order of 3 x104 to 8 x106 mol/yr (and 3 x109 mol/yr of B). These flux estimates are certainly upper limits because low temperature (<200C) gases that make up the majority of emissions have much lower trace element concentrations. Further work is needed to better constrain volatile contributions of volcanoes to the atmosphere, and to improve global geochemical models which assess the impact of volcanic gases on the atmosphere. {[1]} Hilton, Fischer & Marty (2002) Rev. Min. vol 47 for review [2] Kerrick Rev. Geophys. (2001) vol. 39 #4. [3] Symnods, Rose & Reed (1988) nature vol 334, p. 415 [4] Fischer, Shuttleworth & O'Day (1998) Fres. J. Anal. Chem. vol 362, p. 457 [5] Taran et al., (1995) Gochim. Cosmochim. Acta vol. 59, p. 1749

Fischer, T. P.; Hilton, D. R.

2003-12-01

12

Ion-trap detection of volatile organic compounds in alveolar breath  

SciTech Connect

We describe a method for the collection and microanalysis of the volatile organic compounds in human breath. A transportable apparatus supplies subjects with purified air and samples their alveolar breath; the volatile organic compounds are captured in an adsorptive trap containing activated carbon and molecular sieve. The sample is thermally desorbed from the trap in an automated microprocessor-controlled device, concentrated by two-stage cryofocusing, and assayed by gas chromatography with ion-trap detection. Compounds are identified by reference to a computer-based library of mass spectra with subtraction of the background components present in the inspired air. We used this device to study 10 normal subjects and determined the relative abundance of the volatile organic compounds in their alveolar breath. The breath-collecting apparatus was convenient to operate and was well tolerated by human volunteers.

Phillips, M.; Greenberg, J. (Department of Medicine, St. Vincent's Medical Center of Richmond, Staten Island, NY (United States))

1992-01-01

13

Enantiomer distribution of major chiral volatile organic compounds in selected types of herbal honeys.  

PubMed

In this article, volatile organic compounds in 14 honey samples (rosemary, eucalyptus, orange, thyme, sage, and lavender) were identified. Volatile organic compounds were extracted using a solid phase microextraction method followed by gas chromatography connected with mass spectrometry analysis. The studied honey samples were compared based on their volatile organic compounds composition. In total, more than 180 compounds were detected in the studied samples. The detected compounds belong to various chemical classes such as terpenes, alcohols, acids, aldehydes, ketones, esters, norisoprenoids, benzene and furane derivatives, and organic compounds containing sulfur and nitrogen heteroatom. Ten chiral compounds (linalool, trans-linalool oxide, cis-linalool oxide, 4-terpineol, ?-terpineol, hotrienol, and four stereoisomers of lilac aldehydes) were selected for further chiral separation. Chirality 26:670-674, 2014. © 2014 Wiley Periodicals, Inc. PMID:25099214

Pažitná, Alexandra; Džúrová, Jana; Spánik, Ivan

2014-10-01

14

Separation of Ions from Volatile Organic Compounds Using High-Field Asymmetric Waveform Ion Mobility Spectrometry-Mass Spectrometer  

NASA Astrophysics Data System (ADS)

A combination of high-field asymmetric waveform ion mobility spectrometry (FAIMS) with mass spectrometer (MS) was analyzed. FAIMS separates ions from the volatile organic compounds in the gas-phase as an ion-filter for MS. The sample ions were created at ambient pressure by ion source, which was equipped with a 10.6 eV UV discharge lamp (Å = 116.5 nm). The drift tube of FAIMS is composed of two parallel planar electrodes and the dimension is 10 mm × 8 mm × 0.5 mm. FAIMS was investigated when driven by the high-filed rectangular asymmetric waveform with the peak-to-peak voltage of 1.36 kV at the frequency of 1 MHz and the duty cycle of 30%. The acetone, the butanone, and their mixture were adopted to characterize the FAIMS-MS. The mass spectra obtained from MS illustrate that there are ion-molecular reactions between the ions and the sample neutral molecular. And the proton transfer behavior in the mixture of the acetone and the butanone is also observed. With the compensation voltage tuned from -30 V to 10 V with a step size of 0.1 V, the ion pre-separation before MS is realized.

Li, Hua; Wang, Xiao-hao; Tang, Fei; Yang, Ji; Ding, Li

2010-04-01

15

Ion mobility spectrometry for microbial volatile organic compounds: a new identification tool for human pathogenic bacteria.  

PubMed

Presently, 2 to 4 days elapse between sampling at infection suspicion and result of microbial diagnostics. This delay for the identification of pathogens causes quite often a late and/or inappropriate initiation of therapy for patients suffering from infections. Bad outcome and high hospitalization costs are the consequences of these currently existing limited pathogen identification possibilities. For this reason, we aimed to apply the innovative method multi-capillary column-ion mobility spectrometry (MCC-IMS) for a fast identification of human pathogenic bacteria by determination of their characteristic volatile metabolomes. We determined volatile organic compound (VOC) patterns in headspace of 15 human pathogenic bacteria, which were grown for 24 h on Columbia blood agar plates. Besides MCC-IMS determination, we also used thermal desorption-gas chromatography-mass spectrometry measurements to confirm and evaluate obtained MCC-IMS data and if possible to assign volatile compounds to unknown MCC-IMS signals. Up to 21 specific signals have been determined by MCC-IMS for Proteus mirabilis possessing the most VOCs of all investigated strains. Of particular importance is the result that all investigated strains showed different VOC patterns by MCC-IMS using positive and negative ion mode for every single strain. Thus, the discrimination of investigated bacteria is possible by detection of their volatile organic compounds in the chosen experimental setup with the fast and cost-effective method MCC-IMS. In a hospital routine, this method could enable the identification of pathogens already after 24 h with the consequence that a specific therapy could be initiated significantly earlier. PMID:22327321

Jünger, Melanie; Vautz, Wolfgang; Kuhns, Martin; Hofmann, Lena; Ulbricht, Siobhán; Baumbach, Jörg Ingo; Quintel, Michael; Perl, Thorsten

2012-03-01

16

The partitioning of sulfur and chlorine between andesite melts and magmatic volatiles and the exchange coefficients of major cations  

NASA Astrophysics Data System (ADS)

Andesite melts were equilibrated with an H-O-S-bearing volatile phase to determine the partition coefficients for S and Cl as a function of melt composition and oxygen fugacity. The experiments were conducted in rapid-quench MHC vessel assemblies at 200 MPa and 1000 °C, and over a range of imposed fO2 between NNO-1.2 and NNO+1.8. High fluid/melt mass ratios (˜15) were employed, allowing precise and accurate partition coefficients to be obtained by mass balance calculations. Chlorine exhibits Henrian behavior at ClO-0.5 activities typical for arc magmas, with DClvolatile/melt=1.36±0.06 (1?) below 0.2 wt.% Cl in the melt; at higher ClO-0.5 activities, DClvolatile/melt increases linearly to 2.11 ± 0.02 at 1 wt.% Cl in the melt. In the volatile phase: FeCl2 ˜ NaCl > KCl ˜ HCl. The determination of cation exchange coefficients for major cations yielded: KK,Navolatile/melt=1.23±0.10 (1?) and ?KFe,Navolatile/melt=DFevolatile/melt/DNavolatile/melt=1.08±0.16 (1?). Under these conditions, the concentration of HCl in the vapor is negatively correlated with the (Na + K)/(Al + Fe3+) ratio in the melt. Reduced sulfur (S2-) appears to obey Henry's law in andesite melt-volatile system at fH2S below pyrrhotite saturation. The partition coefficient for S at fO2 = NNO-0.5 correlates negatively with the FeO concentration in the melt, changing from 254 ± 25 at 4.0 wt.% FeO to 88 ± 6 at 7.5 wt.% FeO. Pyrrhotite saturation is reached when approximately 3.2 mol% S is present in the volatile phase at fO2 = NNO-0.5. At the sulfide/sulfate transition, the partition coefficient of S drops from 171 ± 23 to 21 ± 1 at a constant FeO content of ˜6 wt.% in the melt. At fO2 = NNO+1.8, anhydrite saturation is reached at ˜3.3 mol% S present in the volatile phase. Aqueous volatiles exsolving from intermediate to mafic magmas can efficiently extract S, and effect its transfer to sites of magmatic-hydrothermal ore deposit formation.

Zajacz, Zoltán; Candela, Philip A.; Piccoli, Philip M.; Sanchez-Valle, Carmen

2012-07-01

17

Multi-Capillary Column-Ion Mobility Spectrometry of Volatile Metabolites Emitted by Saccharomyces Cerevisiae  

PubMed Central

Volatile organic compounds (VOCs) produced during microbial fermentations determine the flavor of fermented food and are of interest for the production of fragrances or food additives. However, the microbial synthesis of these compounds from simple carbon sources has not been well investigated so far. Here, we analyzed the headspace over glucose minimal salt medium cultures of Saccharomyces cerevisiae using multi-capillary column-ion mobility spectrometry (MCC-IMS). The high sensitivity and fast data acquisition of the MCC-IMS enabled online analysis of the fermentation off-gas and 19 specific signals were determined. To four of these volatile compounds, we could assign the metabolites ethanol, 2-pentanone, isobutyric acid, and 2,3-hexanedione by MCC-IMS measurements of pure standards and cross validation with thermal desorption–gas chromatography-mass spectrometry measurements. Despite the huge biochemical knowledge of the biochemistry of the model organism S. cerevisiae, only the biosynthetic pathways for ethanol and isobutyric acid are fully understood, demonstrating the considerable lack of research of volatile metabolites. As monitoring of VOCs produced during microbial fermentations can give valuable insight into the metabolic state of the organism, fast and non-invasive MCC-IMS analyses provide valuable data for process control. PMID:25197771

Halbfeld, Christoph; Ebert, Birgitta E.; Blank, Lars M.

2014-01-01

18

Revalidation of the Volatile Organic Analyzer Following a Major On-Orbit Maintenance Activity  

NASA Technical Reports Server (NTRS)

The Volatile Organic Analyzer (VOA) contributes to the assessment of air quality aboard the International Space Station (ISS) by identifying and quantifying target airborne volatile organic contaminants in the module air. This on-orbit contaminant monitoring capability becomes particularly important during an air quality degradation event such as a system leak. During several ISS air quality degradations, the VOA has generated near real-time data that was used to make decisions or to better understand the contingency. The VOA was operational from January 2002 through June 2003, during which time it was validated by comparing VOA data to simultaneously acquired grab sample containers (GSCs). In January 2003, one of the two analytical channels of the VOA was shutdown because of a component failure, but a redundant channel continued to supply the necessary analytical data. In June 2003, the sole remaining channel was deactivated. Initial assessments of the channel shutdowns pointed to failed fuses or heaters, but neither was considered repairable on orbit. In 2005, it was determined that failed fuses could be replaced on orbit and the crew conducted a diagnostic procedure to identify the failed component. The crew discovered that both channels incurred failed fuses, which lead to a subsequent on orbit maintenance activity and return of the VOA to operational status in December 2005. The VOA has been providing data on the ISS atmosphere since its reactivation in 2005 and this paper will present the VOA data collected during 2006. Special emphasis will be placed upon the revalidation of the repaired VOA using GSCs as well as a summary of the diagnostic and repair procedures.

Limero, Thomas; James, John T.

2007-01-01

19

A Volatile Organic Analyzer for Space Station - Description and evaluation of a gas chromatography/ion mobility spectrometer  

NASA Technical Reports Server (NTRS)

An on-board Volatile Organic Analyzer (VOA), an essential component of the Environmental Health System (EHS) air-quality monitoring strategy, is described. The strategy is aimed at warning the crew and ground personnel if volatile compounds exceed safe exposure limits. The VOA uses a combination of gas chromatography (GC) and ion-mobility spectrometry (IMS) for environmental monitoring and analysis. It is concluded that the VOA dual-mode detection capability and the ion mobilities in the drift region are unique features that can assist in the resolution of coeluting GC peaks. The VOA is capable of accurately identifying and quantifying target compounds in a complex mixture.

Limero, Thomas; Brokenshire, John; Cumming, Colin; Overton, ED; Carney, Ken; Cross, Jay; Eiceman, Gary; James, John

1992-01-01

20

Detection of volatile compounds produced by microbial growth in urine by selected ion flow tube mass spectrometry (SIFT-MS)  

Microsoft Academic Search

Selected ion flow tube-mass spectrometry has been used to measure the volatile compounds occurring in the headspace of urine samples inoculated with common urinary tract infection (UTI)-causing microbes Escherichia coli, Proteus vulgaris, Pseudomonas aeruginosa, Staphylococcus aureus, Staphylococcus epidermidis, Klebsiella pneumoniae, Enterococcus faecalis, or Candida albicans. This technique has the potential to offer rapid and simple diagnosis of the causative agent

Malina K. Storer; Kim Hibbard-Melles; Brett Davis; Jenny Scotter

2011-01-01

21

Major ion toxicity of six produced waters to three freshwater species: Application of ion toxicity models and TIE procedures  

SciTech Connect

Previous research to characterize the acute toxicity of major ions to freshwater organisms resulted in the development of statistical toxicity models for three freshwater species (Ceriodaphnia dubia, Pimephales promelas, and Daphnia magna). These ion toxicity models estimate the toxicity of seven major ions utilizing logistic regression. In this study, the ion toxicity models were used in conjunction with Phase 1 toxicity identification evaluation (TIE) procedures to evaluate the contribution of major ion toxicity to the total toxicity of six produced water samples ranging in total salinity from 1.7 to 58.1 g/L. Initial toxicities of all six samples were compared to the model predictions. Four produced waters were found to have toxicity consistent with toxicity attributable to major ion concentrations only. Two produced waters were found to exhibit more toxicity than expected from ion concentrations alone. These samples were subjected to Phase 1 TIE procedures. Toxicities were reduced by specific Phase 1 TIE manipulations to those predicted by the ion toxicity models. Mock effluents were used to verify the results. The combination of the ion toxicity models with Phase 1 TIE procedures successfully quantified the toxicity due to major ions in six produced water samples.

Tietge, J.E.; Hockett, J.R. [ENSR Consulting and Engineering, Fort Collins, CO (United States); Evans, J.M. [Gas Research Inst., Chicago, IL (United States)

1997-10-01

22

Major ion concentrations and the inorganic carbon chemistry of the Humber rivers  

Microsoft Academic Search

Measurements of major ion concentrations in the main rivers draining into the Humber estuary show two dominant spatial patterns, related to anthropogenic sources from catchments draining urban\\/industrial areas and background weathering sources from the rural catchments. Most major ions exhibit dilution effects with flow, with higher concentrations at baseflow compared with stormflow conditions. This suggests a predominance of point (effluent)

Helen P. Jarvie; Colin Neal; David V. Leach; Geoffery P. Ryland; W. Alan House; Alice J. Robson

1997-01-01

23

Volatile single-source molecular precursor for the lithium ion battery cathode.  

PubMed

The first single-source molecular precursor for a lithium-manganese cathode material is reported. Heterometallic ?-diketonate LiMn(2)(thd)(5) (1, thd = 2,2,6,6-tetramethyl-3,5-heptanedionate) was obtained in high yield by simple one-step solid-state reactions employing commercially available reagents. Substantial scale-up preparation of 1 was achieved using a solution approach. The crystal structure of the precursor contains discrete Li:Mn = 1:2 trinuclear molecules held together by bridging diketonate ligands. The complex is relatively stable in open air, highly volatile, and soluble in all common solvents. It was confirmed to retain its heterometallic structure in solutions of non-coordinating solvents. The heterometallic diketonate 1 was shown to exhibit clean, low-temperature decomposition in air/oxygen that results in nanosized particles of spinel-type oxide LiMn(2)O(4), one of the leading cathode materials for lithium ion batteries. PMID:22443098

Navulla, Anantharamulu; Huynh, Lan; Wei, Zheng; Filatov, Alexander S; Dikarev, Evgeny V

2012-04-01

24

Characteristics of major secondary ions in typical polluted atmospheric aerosols during autumn in central Taiwan.  

PubMed

In autumn of 2008, the chemical characteristics of major secondary ionic aerosols at a suburban site in central Taiwan were measured during an annually occurring season of high pollution. The semicontinuous measurement system measured major soluble inorganic species, including NH(4)(+), NO(3)(-), and SO(4)(2-), in PM(10) with a 15 min resolution time. The atmospheric conditions, except for the influences of typhoons, were dominated by the local sea-land breeze with clear diurnal variations of meteorological parameters and air pollutant concentrations. To evaluate secondary aerosol formation at different ozone levels, daily ozone maximum concentration (O(3,daily max)) was used as an index of photochemical activity for dividing between the heavily polluted period (O(3,daily max) ?80 ppb) and the lightly polluted period (O(3,daily max)<80 ppb). The concentrations of PM(10), NO(3)(-), SO(4)(2-), NH(4)(+) and total major ions during the heavily polluted period were 1.6, 1.9, 2.4, 2.7 and 2.3 times the concentrations during the lightly polluted period, respectively. Results showed that the daily maximum concentrations of PM(10) occurred around midnight and the daily maximum ozone concentration occurred during daytime. The average concentration of SO(2) was higher during daytime, which could be explained by the transportation of coastal industry emissions to the sampling site. In contrast, the high concentration of NO(2) at night was due to the land breeze flow that transport inland urban air masses toward this site. The simulations of breeze circulations and transitions were reflected in transports and distributions of these pollutants. During heavily polluted periods, NO(3)(-) and NH(4)(+) showed a clear diurnal variations with lower concentrations after midday, possibly due to the thermal volatilization of NH(4)NO(3) during daytime and transport of inland urban plume at night. The diurnal variation of PM(10) showed the similar pattern to that of NO(3)(-) and NH(4)(+) aerosols. This indicated that the formatted secondary aerosols in the inland urban area could be transported to the coastal area by the weak land breeze and deteriorated the air quality in the coastal area at night. PMID:21320743

Fang, Guor-Cheng; Lin, Shih-Chieh; Chang, Shih-Yu; Lin, Chuan-Yao; Chou, Charles-C K; Wu, Yun-Jui; Chen, Yu-Chieh; Chen, Wei-Tzu; Wu, Tsai-Lin

2011-06-01

25

Major Ion Chemistry of Shark River Slough, Everglades National Park  

NASA Astrophysics Data System (ADS)

Shark River Slough (SRS) is the dominant surface water flow way in Everglades National Park and its water chemistry is currently being monitored at 6 sites as part of the Florida Coastal Everglades-Long Term Ecological Research program. In order to determine the sources of water, the interactions between the sources of water as well as to calculate residence times of different water source reservoirs and evaporative enrichment, surface water samples were analyzed for major anion and cation concentrations (i.e., Cl, SO2, Ca, K, Mg, and Na). Surface water samples were collected at each site using an ISCO 6172 autosampler, that was programmed to collect a 250-ml sample every 18 h and to composite four such samples into the same 1-liter bottle. Thus, each 1 liter sample represented a 3-day composite. Autosamplers were serviced monthly, and the collected 1 liter of water was split in the laboratory, with one half analyzed for major cations and anions at FIUs hydrogeology laboratory and the other analyzed for total nutrient concentrations at SERCs Nutrient Laboratory. Prior to being analyzed for major cations and anions, the sample was filtered and split again with one half acidified with 10% HCl for the cations analysis. This poster presents the results of the major cations and anions data collected in 2008 and 2009. Chloride and sulfate concentrations in the surface water of SRS tended to be lower and more variable at the most upstream freshwater site as compared to the downstream freshwater sites. The higher variability of the anion concentrations at the most upstream SRS site may be due to its proximity to the water discharge gates along Tamiami Trail that deliver water from the upstream water conservation areas into SRS. The higher concentration and less variability in chloride and sulfate concentrations at the more downstream freshwater sites may be related to greater exposure of the surface water to evaporation.

Neira, N. M.; Matthews, F. A.; Lagomasino, D.; Price, R. M.

2010-12-01

26

Zonation of volatile and major elements in basaltic melt inclusions: a snapshot of syn-eruptive processes  

NASA Astrophysics Data System (ADS)

Significant zonation in volatile and major elements has been discovered in olivine-hosted melt inclusions (MIs) from glassy pillow margins from the Siqueiros Fracture Zone [samples previously studied in 1]. For the most part, components that are compatible in olivine (e.g. MgO) are depleted at the edges of the zoned MIs relative to their centers, whereas components that are incompatible in olivine (e.g. Al2O3, SiO2, Na2O, and S) are enriched near the MI edges. H2O and F are exceptions in that they are incompatible, yet in several MIs they are depleted near the olivine-melt boundary. FeO and CaO are also exceptions in that they show complex features attributable to uphill diffusion. Another complexity is the similarity between the shapes of the SiO2 and Na2O profiles (despite significant differences in measured self and tracer diffusivities of these components [2, 3]), suggesting that the diffusion of these components is strongly coupled. All MIs from this sample suite exhibit zoning profiles, as do a suite of MIs from the Galapagos Islands and the inclusions studied in [4], so this feature may be common in rapidly quenched, glassy inclusions. Preservation of strong zonation in the Siqueiros MIs suggests that it formed in response to crystallization of olivine on the walls of the MIs during or just prior to eruption because, based on known diffusion coefficients, such profiles would be erased by diffusion on time scales on the order of 1 hr. The MgO concentration profiles in several Siqueiros MIs have been used to constrain the cooling history of the inclusions using the results of [5]. The profiles are consistent with an initial slow cooling rate followed by a period of more rapid cooling over a total timescale of ~10 min. Given that they are incompatible in olivine, the observed decreases in the concentrations of H2O and F toward the edges of some Siqueiros inclusions could suggest either uphill diffusion of H2O and F (as observed for H2O in [6] in a granitic composition) or loss of H2O and F into/through the host olivine (observed for H2O in [7-9]). The latter hypothesis would complement the results of [10], who observed elevated H2O and F in olivine adjacent to volatile-rich MIs. [1] Saal et al. (2002) Nature, 419, 451-455. [2] Lesher et al. (1996) Geochimica et Cosmochimica Acta, 60, 405-413. [3] Jambon (1982) Journal of Geophysical Research, 87, 10797-10810. [4] Mercier (2009) PhD thesis, Université Paris - Sud 11. [5] Chen & Zhang (2008) GCA, 72, 4756-4777. [6] Mungall et al. (1998) American Mineralogist, 83, 685-699. [7] Hauri (2002) Chemical Geology, 183, 115-141. [8] Massare et al. (2002) Chemical Geology, 183, 87-98. [9] Portnyagin et al. (2008) EPSL, 272, 541-552. [10] Le Voyer et al. (2010) AGU abstract #V23E-07.

Newcombe, M.; Fabbrizio, A.; Zhang, Y.; Le Voyer, M.; Guan, Y.; Ma, C.; Eiler, J. M.; Saal, A. E.; Stolper, E. M.

2011-12-01

27

Detection of characteristic metabolites of Aspergillus fumigatus and Candida species using ion mobility spectrometry-metabolic profiling by volatile organic compounds.  

PubMed

Volatile metabolites of Aspergillus fumigatus and Candida species can be detected by gas chromatography/mass spectrometry (GC/MS). A multi-capillary column - ion mobility spectrometer (MCC-IMS) was used in this study to assess volatile organic compounds (VOCs) in the headspace above A. fumigatus and the four Candida species Candida albicans, Candida parapsilosis, Candida glabrata and Candida tropicalis in an innovative approach, validated for A. fumigatus and C. albicans by GC/MS analyses. For the detection of VOCs, a special stainless steel measurement chamber for the microbial cultures was used. The gas outlet was either attached to MCC-IMS or to adsorption tubes (Tenax GR) for GC/MS measurements. Isoamyl alcohol, cyclohexanone, 3-octanone and phenethylalcohol can be described as discriminating substances by means of GC/MS. With MCC-IMS, the results for 3-octanone and phenethylalcohol are concordant and additionally to GC/MS, ethanol and two further compounds (p_0642_1/p_683_1 and p_705_3) can be described. Isoamyl alcohol and cyclohexanone were not properly detectable with MCC-IMS. The major advantage of the MCC-IMS system is the feasibility of rapid analysis of complex gas mixtures without pre-concentration or preparation of samples and regardless of water vapour content in an online setup. Discrimination of fungi on genus level of the investigated germs by volatile metabolic profile and therefore detection of VOC is feasible. However, a further discrimination on species level for Candida species was not possible. PMID:21668516

Perl, Thorsten; Jünger, Melanie; Vautz, Wolfgang; Nolte, Jürgen; Kuhns, Martin; Borg-von Zepelin, Margarete; Quintel, Michael

2011-11-01

28

Determination of volatile organics in drinking water with USEPA method 524.2 and the ion trap detector.  

PubMed

New drinking water regulations require the monitoring of eight volatile organic compounds that have established maximum contaminant levels (MCLs) and 51 other volatile organics for which MCLs are not established. A laboratory analytical method (Method 524.2) for the determination of 58 of these compounds is investigated, and precision and accuracy data are obtained. The method uses a standard inert gas purge extraction, isolation of the volatile organics on a three-stage solid-phase trap, thermal desorption into a gas chromatograph, separation with a fused-silica capillary column, and identification and measurement with a relatively low cost, benchtop ion trap detector that functions as a mass spectrometer. At a concentration of 2 micrograms/L (2 parts per billion), the grand mean measurement accuracy for 54 compounds was 95% of the true value with a mean relative standard deviation (RSD) of 4%. At 0.2 micrograms/L (200 parts per trillion), the grand mean measurement accuracy for 52 compounds was 95% of the true value with a mean RSD of 3%. PMID:2273069

Eichelberger, J W; Bellar, T A; Donnelly, J P; Budde, W L

1990-09-01

29

On-site Rapid Detection of Trace Non-volatile Inorganic Explosives by Stand-alone Ion Mobility Spectrometry via Acid-enhanced Evaporization  

PubMed Central

New techniques for the field detection of inorganic improvised explosive devices (IEDs) are urgently developed. Although ion mobility spectrometry (IMS) has been proved to be the most effective method for screening organic explosives, it still faces a major challenge to detect inorganic explosives owing to their low volatilities. Herein, we proposed a strategy for detecting trace inorganic explosives by thermal desorption ion mobility spectrometry (TD-IMS) with sample-to-sample analysis time less than 5?s based on in-situ acidification on the sampling swabs. The responses for typical oxidizers in inorganic explosives, such as KNO3, KClO3 and KClO4 were at least enhanced by a factor of 3000 and their limits of detection were found to be subnanogram. The common organic explosives and their mixtures with inorganic oxidizers were detected, indicating that the acidification process did not affect the detection of organic explosives. Moreover, the typical inorganic explosives such as black powders, firecrackers and match head could be sensitively detected as well. These results demonstrated that this method could be easily employed in the current deployed IMS for on-site sensitive detection of either inorganic explosives or organic ones. PMID:25318960

Peng, Liying; Hua, Lei; Wang, Weiguo; Zhou, Qinghua; Li, Haiyang

2014-01-01

30

On-site Rapid Detection of Trace Non-volatile Inorganic Explosives by Stand-alone Ion Mobility Spectrometry via Acid-enhanced Evaporization  

NASA Astrophysics Data System (ADS)

New techniques for the field detection of inorganic improvised explosive devices (IEDs) are urgently developed. Although ion mobility spectrometry (IMS) has been proved to be the most effective method for screening organic explosives, it still faces a major challenge to detect inorganic explosives owing to their low volatilities. Herein, we proposed a strategy for detecting trace inorganic explosives by thermal desorption ion mobility spectrometry (TD-IMS) with sample-to-sample analysis time less than 5 s based on in-situ acidification on the sampling swabs. The responses for typical oxidizers in inorganic explosives, such as KNO3, KClO3 and KClO4 were at least enhanced by a factor of 3000 and their limits of detection were found to be subnanogram. The common organic explosives and their mixtures with inorganic oxidizers were detected, indicating that the acidification process did not affect the detection of organic explosives. Moreover, the typical inorganic explosives such as black powders, firecrackers and match head could be sensitively detected as well. These results demonstrated that this method could be easily employed in the current deployed IMS for on-site sensitive detection of either inorganic explosives or organic ones.

Peng, Liying; Hua, Lei; Wang, Weiguo; Zhou, Qinghua; Li, Haiyang

2014-10-01

31

On-site Rapid Detection of Trace Non-volatile Inorganic Explosives by Stand-alone Ion Mobility Spectrometry via Acid-enhanced Evaporization.  

PubMed

New techniques for the field detection of inorganic improvised explosive devices (IEDs) are urgently developed. Although ion mobility spectrometry (IMS) has been proved to be the most effective method for screening organic explosives, it still faces a major challenge to detect inorganic explosives owing to their low volatilities. Herein, we proposed a strategy for detecting trace inorganic explosives by thermal desorption ion mobility spectrometry (TD-IMS) with sample-to-sample analysis time less than 5?s based on in-situ acidification on the sampling swabs. The responses for typical oxidizers in inorganic explosives, such as KNO3, KClO3 and KClO4 were at least enhanced by a factor of 3000 and their limits of detection were found to be subnanogram. The common organic explosives and their mixtures with inorganic oxidizers were detected, indicating that the acidification process did not affect the detection of organic explosives. Moreover, the typical inorganic explosives such as black powders, firecrackers and match head could be sensitively detected as well. These results demonstrated that this method could be easily employed in the current deployed IMS for on-site sensitive detection of either inorganic explosives or organic ones. PMID:25318960

Peng, Liying; Hua, Lei; Wang, Weiguo; Zhou, Qinghua; Li, Haiyang

2014-01-01

32

Perturbations in major ion chemistry of Taylor Slough, Everglades National Park, Florida, USA  

NASA Astrophysics Data System (ADS)

Wetland ecosystems are influenced by perturbations in the cycling of water, nutrients, and other biogeochemically active elements. The purpose of this study was focused on identifying perturbations in major ion chemistry of Taylor Slough, Everglades National Park (ENP) Florida, and to attempt to identify the sources of the perturbations. Water samples were collected from 5 Florida Coastal Everglades-Long Term Ecological Research sites located along a freshwater upland to coastal transect. Composite samples were collected every three days using an ISCO sampler, and were analyzed for major cations and anions during a two-year period ranging from 2008-2010. As expected, the surface water chemistry at the upland sites contained lower ion concentrations than the coastal sites. However, a decrease in ion concentrations at the upland sites in a downstream direction varied from an increase in ion concentration at the coastal sites. This variation may be due to retardation of the ions by sediments and vegetation and proximity to Florida Bay respectively. Seasonal differences in the ion concentrations were observed as well as episodic changes in response to the passage of hurricanes.

Sandoval, E.; Price, R. M.

2010-12-01

33

MAJOR ION HYDROGEOCHEMICAL BUDGETS AND ELEVATED CHLORIDE CONCENTRATIONS IN SENECA LAKE, NEW YORK  

Microsoft Academic Search

Water samples were periodically collected from four lake sites (surface and 2 deep water samples) and seventeen streams within the Seneca Lake watershed from May 2000 through November 2004 and analyzed for the major ions (Cl - , Na + , SO4 2- , K + ,

John D. Halfman; Caterina M. Caiazza; Robert J. Stewart; Suzanne M. Opalka; Clare K. Morgan

34

New developments for direct monitoring of volatile compounds with an ion trap/time-of-flight mass spectrometer  

SciTech Connect

A new type of direct air-monitoring has been developed that provides real-time, trace detection of a broad range of volatile compounds. This system is being designed for low to sub-part-per-trillion detection and analysis rates of 10-100 milliseconds per scan. To achieve these objectives, an atmospheric-sampling glow discharge ionization (ASGDI) source has been combined with an ion storage trap/time-of-flight mass spectrometer (IS/TOF-MS). The ASGDI source has a high ionization efficiency for a broad class of compounds (comparable to atmospheric pressure ionization), but is separated by one less vacuum stage from the mass analyzer chamber. The ion storage trap serves to interface the ASGDI source and the TOF-MS by providing an effective means for converting the continuum ion beam into discrete pulses. TOF-MS was chosen for this application for its high transmission efficiency (i.e., near 50%) and fast analysis times (i.e., 1000 Da in under 100 {mu}s).

Chambers, D.M.; Thomas, S.W.; Andresen, B.D. [Lawrence Livermore National Lab., CA (United States)

1994-12-31

35

Origin of major ions in monthly rainfall events at the Bamenda Highlands, Northwest Cameroon.  

PubMed

Rainwater characteristics can reveal emissions from various anthropogenic and natural sources into the atmosphere. The physico-chemical characteristics of 44 monthly rainfall events (collected between January and December 2012) from 4 weather stations (Bamenda, Ndop plain, Ndawara and Kumbo) in the Bamenda Highlands (BH) were investigated. The purpose was to determine the sources of chemical species, their seasonal inputs and suitability of the rainwater for drinking. The mean pH of 5 indicated the slightly acidic nature of the rainwater. Average total dissolved solids (TDS) were low (6.7 mg/L), characteristic of unpolluted atmospheric moisture/air. Major ion concentrations (mg/L) were low and in the order K(+) > Ca(2+) > Mg(2+) > Na(+) for cations and NO3(-)?HCO3(-)>SO4(2-)>Cl(-)>PO4(3-)>F(-) for anions. The average rainwater in the area was mixed Ca-Mg-SO4-Cl water type. The Cl(-)/Na(+) ratio (1.04) was comparable to that of seawater (1.16), an indication that Na(+) and Cl(-) originated mainly from marine (Atlantic Ocean) aerosols. High enrichments of Ca(2+), Mg(2+) and SO(2-)4 to Na(+) ratios relative to seawater ratios (constituting 44% of the total ions) demonstrated their terrigenous origin, mainly from Saharan and Sahelian arid dusts. The K(+)/Na(+) ratio (2.24), which was similar to tropical vegetation ash (2.38), and NO3(-) was essentially from biomass burning. Light (< 100 mm) pre-monsoon and post-monsoon convective rains were enriched in major ions than the heavy (> 100 mm) monsoon rains, indicating a high contribution of major ions during the low convective showers. Despite the acidic nature, the TDS and major ion concentrations classified the rainwater as potable based on the WHO guidelines. PMID:25079410

Wirmvem, Mengnjo J; Ohba, Takeshi; Fantong, Wilson Y; Ayonghe, Samuel N; Hogarh, Jonathan N; Suila, Justice Y; Asaah, Asobo Nkengmatia E; Ooki, Seigo; Tanyileke, Gregory; Hell, Joseph V

2014-04-01

36

ICRH of JET and LHD Majority Ions at Their Fundamental Cyclotron Frequency  

NASA Astrophysics Data System (ADS)

Results of the experimental studies of ICRH at the fundamental cyclotron frequency of the majority deuterons in JET plasmas with near-tangential deuteron neutral beam injection (NBI) are presented. 1D, 2D and 3D ICRH modeling indicated that several ITER relevant mechanisms of heating may occur simultaneously in this heating scheme: fundamental ion cyclotron resonance heating of majority and beam D ions, impurity ion heating and electron heating due to Landau damping and TTMP. These mechanisms were studied in JET experiments with a ˜90% D, 5% H plasma including traces of Be and Ar. Up to 2MW of ICRH power was applied at 25 MHz to NBI heated plasmas. In most of the discharges the toroidal magnetic field strength was 3.3T, but in one it was equal to 3.6T. The E+ component of the electric field governs the ion cyclotron heating of not too fast particles. The Doppler shifted RF absorption of the beam deuterons away from the cold resonance at which E+ is small was exploited to enhance the RF power absorption efficiency. Fundamental ICRH experiments were also carried out in LHD hydrogen plasma with high energy hydrogen NBI. ICRH was performed at 38MHz with injected power <1 MW. The effect of fundamental ICRH was clearly demonstrated in both machines.

Krasilnikov, A. V.; Van Eester, D.; Lerche, E.; Ongena, J.; Mailloux, J.; Stamp, M.; Jachmich, S.; Leggate, H.; Vdovin, V.; Walden, A.; Mayoral, M.-L.; Bonheure, G.; Santala, M.; Kiptily, V.; Popovichev, S.; Biewer, T.; Crombe, K.; Esposito, B.; Marocco, D.; Riva, M.; Kaschuck, Yu. A.; Amosov, V. N.; Ericsson, G.; Giacomelli, L.; Hellesen, C.; Hjalmarsson, A.; Kallne, J.; Isobe, M.; Nishiura, M.; Sasao, M.; Nishimura, H.; Saito, K.; Seki, T.; Mutoh, T.; Kumazawa, R.; Takeiri, Y.; Osakabe, M.; Goto, M.; Murakami, S.; Goncharov, P.

2007-09-01

37

Energy spectra of the major ion species in the ring current during geomagnetic storms  

Microsoft Academic Search

Using the University of Maryland\\/Max-Planck-Institut fuer Aeronomie charge-energy-mass (CHEM) spectrometer on the AMPTE Charge Composition Explorer (CCE) spacecraft, we have examined the nearly equatorial storm time energy spectra of four major magnetospheric ions, H\\/sup +\\/, O\\/sup +\\/, He\\/sup +\\/, and He\\/sup - -\\/, over the energy range 1--300 keV\\/e in the L range 3--6. The data were obtained during the

L. M. Kistler; F. M. Ipavich; D. C. Hamilton; G. Gloeckler; B. Wilken; G. Kremser; W. Stuedemann

1989-01-01

38

Strontium isotope and major ion chemistry of the rainwaters from Guiyang, Guizhou Province, China  

Microsoft Academic Search

Twenty-two rainwater samples from Guiyang city, southwestern China, have been analyzed for their chemical compositions and 87Sr\\/86Sr ratios, with a main purpose to get a better understanding of the general features of rainwater in Guiyang city and their correspondences to human activities. The rainwaters studied are almost acidic (pH=4.53) and show big changes in major ion composition. Ca2+ and Mg2+

Guilin Han; Cong-Qiang Liu

2006-01-01

39

Effects of hydrogen peroxide on the content of major volatile halogenated compounds in the red alga Asparagopsis taxiformis (Bonnemaisoniaceae)  

Microsoft Academic Search

The genus Asparagopsis is a prolific source of halogenated metabolites. Due to its commercial applications, it has been intensively cultivated in\\u000a southern Portugal. In the present study, we assess if the internal levels of the major halogenated metabolites (bromoform\\u000a and dibromoacetic acid) in Asparagopsis taxiformis can be increased with hydrogen peroxide (H2O2) addition. Previous studies with red algae showed that

Leonardo Mata; Helena Gaspar; Fátima Justino; Rui Santos

40

Sources and cycling of major ions and nutrients in Devils Lake, North Dakota  

USGS Publications Warehouse

Devils Lake is a saline lake in a large, closed drainage basin in northeastern North Dakota. Previous studies determined that major-ion and nutrient concentrations in Devils Lake are strongly affected by microbially mediated sulfate reduction and dissolution of sulfate and carbonate minerals in the bottom sediments. These studies documented substantial spatial variability in the magnitude of calculated benthic fluxes coincident with the horizontal salinity gradient in Devils Lake. The purpose of the present study is to evaluate seasonal variability in benthic-flux rates, and to understand the effect of these fluxes on the major- chemistries in Devils Lake between May and October 1991. During the study period, the water column was well mixed, and specific conductance, pH, and temperature did not vary with depth. Dissolved oxygen was enriched near the lake surface due to photosynthesis. Major-ion concentrations and nutrient concentrations did not vary with depth. Because the water-quality data were obtained during open-water periods, the vertical profiles reflect well-mixed conditions. However, the first and last profiles for the study period did document near-bottom maxima of major cations. Secchi-disk depth varied from 0.82 meter on May 7, 1991, to 2.13 meters on June 5, 1991. The mean Secchi-disk depth during the study period was 1.24 meters. Seasonal variations in Secchi-disk depths were attributed to variations in primary productivity and phytoplankton communities. Nutrient cycles in Devils Lake were evaluated using gross primary productivity rate data, sediment trap data, and major-ion and nutrient benthic-flux rate data. Gross primary productivity rate was smallest in May (0.076 gram of carbon per square meter per day) and largest in September (1.8 grams of carbon per square meter per day). Average gross primary productivity for the study period was 0.87 gram of carbon per square meter per day. Average gross primary productivity is consistent with historic data from Devils Lake and with data from other eutrophic lakes. The average flux of organic carbon for the study period was 12 grams per square meter per day. The calculated carbon to nitrogen to phosphorus ratio (317:25:1) is similar to the Redfield ratio (106:16:1); therefore, most organic matter probably is derived from lacustrine phytoplankton. Calculated benthic-flux rates indicated that bottom sediments are important sources of majorions and nutrients to Devils Lake. Only one of the cores collected during this study indicated a net sulfate flux from the lake into the sediments. Seasonal variations in major-ion and nutrient benthic fluxes generally were small. However, there were important differences between the calculated benthic fluxes for this study and the calculated benthic fluxes for 1990. Calculated benthic fluxes of bicarbonate, ammonia, and phosphorus for this study were smaller than calculated benthic fluxes for 1990. The large differences between fluxes for 1990 and 1991 were attributed to calm, stratified water-column conditions in 1990 and well-mixed water-column conditions in 1991. The role of benthic fluxes in the chemical mass balances in Devils Lake was evaluated by calculating response times for major ions and nutrients in Devils Lake. The calculated response times for major ions in Devils Lake ranged from 6.7 years for bicarbonate to 34 years for sulfur (as S04). The response times for major ions are significantly shorter than previous estimates that did not include benthic fluxes. In addition, the relatively short response times for nitrogen (4.2 years) and phosphorus (0.95 year) indicate that nutrients are recycled rapidly between bottom sediments and the lake. During the study period, benthic fluxes were the dominant source of major ions and nutrients to Devils Lake and greatly reduced the response times of all major ions and nutrients for Devils Lake. As a result, bottom-sediment processes appear to buffer major-ion and nutrient concent

Lent, R.M.

1994-01-01

41

[Major ion chemistry of surface water in the Xilin River Basin and the possible controls].  

PubMed

Under the increasing pressure of water shortage and steppe degradation, information on the hydrological cycle in the steppe region in Inner Mongolia is urgently needed. Major ions are widely used to identify the hydrological processes in a river basin. Based on the analysis results of 239 river water samples collected in 13 sections along the Xilin River system during 2006 to 2008, combined with data from groundwater and precipitation samples collected in the same period and the meteorological and hydrological data in the Xilin River Basin, hydrochemical characteristics and the chemistry of major ions of the Xilin River water have been studied by means of Piper triangle plots and Gibbs diagrams. The results showed that: (1) the total dissolved solid (TDS) in river water mainly ranged between 136.7 mg x L(-1) and 376.5 mg x L(-1), and (2) it had an increasing trend along the river flow path. (3) The major cations and anions of river water were Ca2+ and HCO3-, respectively, and the chemical type of the river water varied from HCO3- -Ca2+ in the headwater area to HCO(3-)-Ca2+ Mg2+ in the lower part. (4) The variation in the concentration of major irons in surface water was not significant at the temporal scale. Usually, the concentration values of major irons were much higher in May than those in other months during the runoff season, while the values were a bit lower in 2007 than those in 2006 and 2008. Except for SO4(2-), the concentrations of other ions such as Ca2+, Na+, Mg2+, K+, Cl- and HCO3- showed a upward trend along the river flow path. Comparing major ion concentrations of the river water with those of local groundwater and precipitation, the concentration in river water was between those of precipitation and groundwater but was much closer to the concentration of groundwater. This indicated that the surface water was recharged by a mixture of precipitation and groundwater, and groundwater showed a larger impact. The Gibbs plot revealed that the chemical compositions of the river water were mainly affected by rock weathering in the drainage area. PMID:24720196

Tang, Xi-Wen; Wu, Jin-Kui

2014-01-01

42

Detection of volatile organic compounds (VOCs) in exhaled breath of patients with chronic obstructive pulmonary disease (COPD) by ion mobility spectrometry  

Microsoft Academic Search

COPD is a disease characterised by a chronic inflammation of the airways and a not fully reversible airway obstruction. The\\u000a spirometry is considered as gold-standard to diagnose the disease and to grade its severity. In this study we used the methodology\\u000a of Ion Mobility Spectometry in order to detect Volatile Organic Compounds (VOCs) in exhaled breath of patients with COPD.

Vasiliki Bessa; Kaid Darwiche; Helmut Teschler; Urte Sommerwerck; Thomas Rabis; Joerg I. Baumbach; Lutz Freitag

2011-01-01

43

Statistical models to predict the toxicity of major ions to Ceriodaphnia dubia, Daphnia magna and Pimephales promelas (fathead minnows)  

Microsoft Academic Search

Toxicity of fresh waters with high total dissolved solids has been shown to be dependent on the specific ionic composition of the water. To provide a predictive tool to assess toxicity attributable to major ions, the authors tested the toxicity of over 2,900 ion solutions using the daphnids, Ceriodaphnia dubia and Daphnia magna, and fathead minnows (Pimephales promelas). Multiple logistic

David R. Mount; David D. Gulley; J. Russell Hockett; Tyler D. Garrison; James M. Evans

1997-01-01

44

Determination of the volatile fraction of Polygonum bistorta L. at different growing stages and evaluation of its antimicrobial activity against two major honeybee (Apis mellifera) pathogens.  

PubMed

The composition of the volatile fraction of Polygonum bistorta L. (also known as bistort or snakeroot) was investigated. Fresh aerial parts of this plant species were collected in the Western Italian Alps during the summer at three different phenological stages, namely vegetative, flowering, and fruiting, and steam-distilled in a Clevenger-type apparatus. The oils accounted for 0.004 to 0.010% of the fresh plant material, and their compositions were determined by GC/FID and GC/MS. The composition of the oils during the vegetative period varied both in quantity and quality; several classes of compounds were found with a predominance of alcohols in the vegetative phase, terpenes and linear-chained saturated hydrocarbons in the flowering phase, while saturated aliphatic acids and their methyl esters were predominant in fruiting phase. The most abundant compounds were 3-methylbut-3-en-1-ol in the vegetative phase, linalool in the flowering phase, and dodecanoic acid and its methyl ester in the fruiting phase. The obtained essential oils were then tested against two major bee pathogens, i.e., Paenibacillus larvae and Melissococcus plutonius, and against a reference bacterial species, Bacillus subtilis. Data were compared to those obtained with reference standards used against those pathogens such as the essential oils obtained from leaves and bark of Cinnamomum zeylanicum (cinnamon), and the antibiotic oxytetracyclin. PMID:22344911

Cecotti, Roberto; Carpana, Emanuele; Falchero, Luca; Paoletti, Renato; Tava, Aldo

2012-02-01

45

Major ion chemistry and weathering processes in the Midyan Basin, northwestern Saudi Arabia.  

PubMed

Chemical characteristics of 72 groundwater samples collected from Midyan Basin have been studied to evaluate major ion chemistry together with the geochemical and weathering processes controlling the water composition. Water chemistry of the study area is mainly dominated by Na, Ca, SO4, and Cl. The molar ratios of (Ca?+?Mg)/total cations, (Na?+?K)/total cations, (Ca?+?Mg)/(Na?+?K), (Ca?+?Mg)/(HCO3?+?SO4), (Ca?+?Mg)/HCO3, and Na/Cl reveal that water chemistry of the Midyan Basin is controlled by evaporite dissolution (gypsum and/or anhydrite, and halite), silicate weathering, and minor contribution of carbonate weathering. The studied groundwater samples are largely undersaturated with respect to dolomite, gypsum, and anhydrite. These waters are capable of dissolving more of these minerals under suitable physicochemical conditions. PMID:23609922

Ghrefat, Habes A; Batayneh, Awni; Zaman, Haider; Zumlot, Taisser; Elawadi, Eslam; Nazzal, Yousef

2013-10-01

46

Time study of trace elements and major ions during two cloud events at the Mt. Brocken  

NASA Astrophysics Data System (ADS)

Cloud water investigations have been performed at the highest elevation of Central Germany in 1997. Results of extensive trace element measurements are presented. Besides conductivity, pH, liquid water content and major ions the data set includes 49 minor and trace elements. Estimation of crustal enrichment factors (EFs) provides an indication of the anthropogenic contributions to the cloud water concentrations. The variation of cloud composition with time has been illustrated for two selected events with different air mass origins. The chemical composition of the cloud condensation nuclei on which the droplets grow mainly determines the cloud water chemistry. For a cloud event in June 1997 the concentrations of the crustally derived elements Si, Al, Fe, Ti, Ce, La and Nd follow each other closely. The fact that SO 42-, NO 3- and NH 4+ are only moderately correlated with the particular pollutants with high enrichment factors such as Cd, Sb, Pb, Zn, Cu, As, Bi, Sn, Mo, Ni, Tl and V indicates that their source regions are more widespread. During an event in October 1997 the time trends for most minor and trace elements follow rather closely those for the major ions NH 4+, SO 42- and NO 3-. Back trajectories show that the transport from continental and marine European sources was the likely cause of the sample concentrations. EFs of trace elements in cloud water samples during the June and October event show a strong correlation with those obtained for urban particulate matter. Although both events are influenced by air masses of different origin, there is a good agreement between the EF signatures.

Plessow, K.; Acker, K.; Heinrichs, H.; Möller, D.

47

Solar Ion Processing of Major Element Surface Compositions of Mature Mare Soils: Insights from Combined XPS and Analytical TEM Observations  

NASA Technical Reports Server (NTRS)

Solar wind ions are capable of altering the sur-face chemistry of the lunar regolith by a number of mechanisms including preferential sputtering, radiation-enhanced diffusion and sputter erosion of space weathered surfaces containing pre-existing compositional profiles. We have previously reported in-situ ion irradiation experiments supported by X-ray photoelectron spectroscopy (XPS) and analytical TEM that show how solar ions potentially drive Fe and Ti reduction at the monolayer scale as well as the 10-100 nm depth scale in lunar soils [1]. Here we report experimental data on the effect of ion irradiation on the major element surface composition in a mature mare soil.

Christoffersen, R.; Dukes, C.; Keller, L. P.; Baragiola, R.

2012-01-01

48

Volatile (sulphur and chlorine), major, and trace element geochemistry of mafic to intermediate tephras from the Chilean Southern Volcanic Zone (33-43°S)  

NASA Astrophysics Data System (ADS)

Here we present the first systematic investigation of volatile geochemistry along the Southern Volcanic Zone (SVZ) of Chile. Holocene olivine-hosted melt inclusions in the most mafic tephras sampled from 16 volcanoes along the volcanic front of the SVZ between 33°S and 43°S were analysed for pre-eruptive sulphur, chlorine, and major element contents. These results are combined with trace element compositions of the host whole rocks. The highest fractionation-corrected gas contents occur in the least-degassed melt inclusions from small monogenetic cones of Los Hornitos, Cabeza de Vaca, and Apagado from both the transitional and the southern-central SVZ, reaching ~3,000 ?g/g S and 1,400 ?g/g Cl, while the lowest abundances of ~1,100 ?g/g S and ~600 ?g/g Cl were found in the central SVZ at Volcán Lonquimay, Volcán Llaima, and Volcán Villarrica. Chlorine co-varies with trace element indicators for the degree of melting and/or source enrichment, such that the lowest Cl contents are found in high-degree melts from the most depleted mantle sources. The size of the volcanic edifices correlates inversely with Cl abundances in the melt. This could reflect more extensive degassing during ascent through the complex magma plumbing systems beneath the stratovolcanoes or greater dilution during larger degrees of melting of more depleted sources, or a combination of these factors. Compared to other subduction zones, the SVZ melt inclusions exhibit Cl and S abundances in the same range as most of those from the Central American and those from the Marianas arcs.

Wehrmann, Heidi; Hoernle, Kaj; Jacques, Guillaume; Garbe-Schönberg, Dieter; Schumann, Kai; Mahlke, Julia; Lara, Luis E.

2014-10-01

49

Fractional contribution of major ions to the membrane potential of Drosophila melanogaster oocytes.  

PubMed

In ovarian follicles of Drosophila melanogaster, ion substitution experiments revealed that K(+) is the greatest contributor (68%) in setting oocyte steady-state potential (E(m)), while Mg(2+) and a metabolic component account for the rest. Because of the intense use made of Drosophila ovarian follicles in many lines of research, it is important to know how changes in the surrounding medium, particularly in major diffusible ions, may affect the physiology of the cells. The contributions made to the Drosophila oocyte membrane potential (E(m)) by [Na(+)](o), [K(+)](o), [Mg(2+)](o), [Ca(2+)](o), [Cl(-)](o), and pH (protons) were determined by substitutions made to the composition of the incubation medium. Only K(+) and Mg(2+) were found to participate in setting the level of E(m). In follicles subjected to changes in external pH from the normal 7.3 to either pH 6 or pH 8, E(m) changed rapidly by about 6 mV, but within 8 min had returned to the original E(m). Approximately half of all follicles exposed to reduced [Cl(-)](o) showed no change in E(m), and these all had input resistances of 330 kOmega or greater. The remaining follicles had smaller input resistances, and these first depolarized by about 5 mV. Over several minutes, their input resistances increased and they repolarized to a value more electronegative than their value prior to reduction in [Cl(-)](o). Together, K(+) and Mg(2+) accounted for up to 87% of measured steady-state potential. Treatment with sodium azide, ammonium vanadate, or chilling revealed a metabolically driven component that could account for the remaining 13%. PMID:19241411

Munley, Susan M; Kinzeler, Sandra; Lizzano, Rebecca; Woodruff, Richard I

2009-04-01

50

Seasonal Variability of Major Ions and ?13CDIC in Permafrost Watersheds of Arctic Alaska  

NASA Astrophysics Data System (ADS)

Models and observations predict that climate change will have more severe effects at higher latitudes. Many effects may already be underway. Increasing temperatures are expected to thaw permafrost soils, changing the hydrology and biogeochemistry of Arctic watersheds. These changes are particularly important because permafrost thaw could destabilize a large carbon reservoir, potentially leading to sizable greenhouse gas emissions. Tracking soil thaw and concomitant changes in carbon export are therefore critical to predicting feedbacks between Arctic climate change and global warming. As the climate warms, the seasonally thawed active layer will extend into deeper, previously frozen, mineral-rich soils, increasing the signal of chemical weathering in streams. Historical methods of monitoring active layer thaw depth are labor intensive and may not capture the heterogeneity of Arctic soils, whereas stream geochemistry provides a unique opportunity to integrate signals across vast spatial distances. We present major ion geochemistry and ?13C of dissolved inorganic carbon (DIC) variations that relate to seasonal changes in permafrost thaw depths. Samples were collected from six watersheds on the North Slope of Alaska. All rivers drain continuous permafrost but three drain tussock tundra-dominated watersheds and three drain bare bedrock catchments with minor tundra influences. Water samples were collected from April until October in 2009 and 2010. The major ion and ?13CDIC trends of tundra streams suggest that silicate weathering dominates during the spring melt while carbonate weathering dominates as the active layer deepens in the summer. In tundra streams, early season ?13CDIC values indicate carbonic acid-silicate weathering. Summer ?13CDIC values indicate carbonic acid-carbonate weathering. In both cases, carbonic acid forms from CO2 produced by the microbial decomposition of C3 organic matter. Bedrock streams have nearly constant ?13CDIC values and high dissolved sulfate concentrations through the year, indicating sulfuric acid-carbonate weathering. In late fall of 2010, ?13CDIC decreases in all streams suggest increased CO2 from a source with relatively negative ?13C values, possibly methane oxidation in soils. The difference between the tundra and bedrock streams allows us to clearly isolate the effect of soil thaw on stream geochemistry. Our initial findings illustrate how seasonal changes in mineral weathering have potential for tracking active layer dynamics.

Lehn, G. O.; Jacobson, A. D.; Douglas, T. A.; McClelland, J. W.; Khosh, M. S.; Barker, A. J.

2011-12-01

51

Two-stage chemical fractionation method for the analysis of elements and non-volatile inorganic ions in PM10 samples: Application to ambient samples collected in Rome (Italy)  

NASA Astrophysics Data System (ADS)

A two-stage micro-analytical scheme for the determination of metals and ions in atmospheric particulate matter collected on only one Teflon filter was developed. In the first stage the collected particles are chemically fractionated for their solubility in a pH-buffered extracting solution; in the second stage the residue is mineralised. The major non-volatile inorganic ions (Cl -, NO 3-, SO 42-, Na +, NH 4+, Ca 2+, Mg 2+) are determined in the first fraction by ion-chromatography (IC), while metals and metalloids (Al, As, Cd, Cr, Cu, Fe, Mg, Mn, Ni, Pb, S, Sb, Se, Si, Ti, V, Zn) are determined in both the acetate extractable and the mineralised residual fractions by inductively coupled plasma optical emission spectroscopy (ICP-OES). The procedure was applied to ambient 24-h PM 10 samples collected on Teflon filters during two field campaigns carried out at two sites in the area of Rome (Italy). The variations in the chemical composition of the collected particles during the two periods were interpreted in the light of the dilution properties of the lower atmosphere and of the back-trajectories of the air masses. The difference in the results between the two locations was interpreted in the light of their proximity to the emission sources. It was found that the acetate extractable and the mineralised residual fraction of some metals exhibit a different temporal pattern, suggesting the existence of different emission sources of the two fractions.

Canepari, Silvia; Cardarelli, Enrico; Perrino, Cinzia; Catrambone, Maria; Pietrodangelo, Adriana; Strincone, Marco

52

Assessment of seawater impact using major hydrochemical ions: a case study from Sadras, Tamilnadu, India.  

PubMed

The impact of seawater intrusion was investigated using major hydrogeochemical ions to evaluate the origin of salinity in Sadras watershed located between Buckingham Canal and Bay of Bengal in the southeastern coast of India. From empirical data collected twice during pre- and post-monsoon seasons, it was found that groundwater was slightly acidic to mildly alkaline, and more than 44% of groundwater samples had EC > 3,000 ?S/cm in both the seasons. Results of principle component analysis (PCA) showed that Na(?+?), Cl(?-?), Mg(2?+?), and SO[Formula: see text] concentrations had the highest loading factor and the samples affected by saline/seawater were separated from the cluster. Hydrochemical processes that accompany the saline/seawater were identified using ionic changes. It was observed during sampling periods that the mixing due to saline/seawater intrusion varied from 4.82-7.86%. Negative values of ionic change (e (change)) for Na(?+?) and K(?+?) decreased with the increasing fraction of seawater. Furthermore, salinity, sodium adsorption ratio, percentage of sodium Na (%), and exchangeable sodium percentage in well samples showed that groundwater was unsuitable for irrigation purposes. PMID:20711862

Mondal, N C; Singh, V S; Saxena, V K; Singh, V P

2011-06-01

53

Ion Channel-Forming Alamethicin Is a Potent Elicitor of Volatile Biosynthesis and Tendril Coiling. Cross Talk between Jasmonate and Salicylate Signaling in Lima Bean1  

PubMed Central

Alamethicin (ALA), a voltage-gated, ion channel-forming peptide mixture from Trichoderma viride, is a potent elicitor of the biosynthesis of volatile compounds in lima bean (Phaseolus lunatus). Unlike elicitation with jasmonic acid or herbivore damage, the blend of substances emitted comprises only the two homoterpenes, 4,11-dimethylnona-1,3,7-triene and 4,8,12-trimethyltrideca-1,3,7,11-tetraene, and methyl salicylate. Inhibition of octadecanoid signaling by aristolochic acid and phenidone as well as mass spectrometric analysis of endogenous jasmonate demonstrate that ALA induces the biosynthesis of volatile compounds principally via the octadecanoid-signaling pathway (20-fold increase of jasmonic acid). ALA also up-regulates salicylate biosynthesis, and the time course of the production of endogenous salicylate correlates well with the appearance of the methyl ester in the gas phase. The massive up-regulation of the SA-pathway (90-fold) interferes with steps in the biosynthetic pathway downstream of 12-oxophytodienoic acid and thereby reduces the pattern of emitted volatiles to compounds previously shown to be induced by early octadecanoids. ALA also induces tendril coiling in various species like Pisum, Lathyrus, and Bryonia, but the response appears to be independent from octadecanoid biosynthesis, because inhibitors of lipoxygenase and phospholipase A2 do not prevent the coiling reaction. PMID:11154344

Engelberth, Jurgen; Koch, Thomas; Schuler, Gode; Bachmann, Nadine; Rechtenbach, Jana; Boland, Wilhelm

2001-01-01

54

GC/MS-positive ion chemical ionization and MS/MS study of volatile benzene compounds in five different woods used in barrel making.  

PubMed

Extracts from acacia, chestnut, cherry, mulberry, and oak wood, used in making barrels for aging wine and spirits were studied by GC/MS positive ion chemical ionization (PICI). Wood chips were extracted by a 50% water/ethanol solution and a tartrate buffer pH 3.2-12% ethanol (model wine) solution. The principal compounds identified in extracts were guaiacol-containing aldehydes and alcohols, such as benzaldehyde and derivatives, vanillin and syringaldehyde, cinnamaldehyde and coniferaldehyde, eugenol and methoxyeugenol, guaiacol and methoxyguaiacol derivatives. PICI using methane as reagent gas produced a high yield of the protonated molecular ion of volatile phenols, compound identification was confirmed by collision-induced-dissociation (CID) experiments on [M + H](+) species. MS/MS fragmentation patterns were studied with standard compounds: guaiacol-containing molecules were characterized by neutral methyl and methanol losses, benzaldehyde derivatives by CO loss. Acacia wood extracts contained significant syringaldehyde and anisaldehyde, but no eugenol and methoxyeugenol. Significant syringaldehyde, eugenol and methoxyeugenol, and high vanillin were found in chestnut and oak wood extracts; low presence of volatile benzene compounds was found in mulberry wood extracts. Cherry wood extracts were characterized by the presence of several benzaldehyde derivatives and high trimethoxyphenol. PMID:17370248

Flamini, Riccardo; Dalla Vedova, Antonio; Cancian, Davide; Panighel, Annarita; De Rosso, Mirko

2007-05-01

55

Cometary coma ions. [which occur when water is the major constituent  

NASA Technical Reports Server (NTRS)

For comets whose nuclei are composed of water ice conglomerates it is shown that the ion H3O(+) can predominate to distances of 5000 km in the subsolar direction. Beyond this distance H2O(+) is the most important ion. The crossover point is a sensitive function of the rate of evaporation from the nucleus. The presence of ammonia or metals such as sodium, in concentrations greater than 0.1% H2O, can lead to NH4(+) and Na(+) ions.

Aikin, A. C.

1974-01-01

56

Major ion chemistry of the Ganga-Brahmaputra river system: Weathering processes and fluxes to the Bay of Bengal  

Microsoft Academic Search

The Ganga-Brahmaputra, one of the world's largest river systems, is first in terms of sediment transport and fourth in terms of water discharge. A detailed and systematic study of the major ion chemistry of these rivers and their tributaries, as well as the clay mineral composition of the bed sediments has been conducted. The chemistry of the highland rivers (upper

M. M. Sarin; S. Krishnaswami; K. Dilli; B. L. K. Somayajulu; W. S. Moore

1989-01-01

57

Resection is a major repair pathway of heavy ion-induced DNA lesions  

NASA Astrophysics Data System (ADS)

Space radiation include densely ionizing heavy ions, which can produce clustered DNA damage with high frequency in human cells. Repair of these complex lesions is generally assumed to be more difficult than for simple double-strand breaks. We show here that human cells use break resection with increasing frequency after exposure to heavy ions. Resection can lead to misrepair of the DNA lesion, via microhomology mediated end-joining. Resection can therefore be responsible for the increased effectiveness of heavy ions in the induction of mutations and genetic late effects.

Durante, Marco; Averbeck, Nicole; Taucher-Scholz, Gisela

58

DIRECT TRACE ANALYSIS OF VOLATILE ORGANIC COMPOUNDS IN AIR USING ION TRAP MASS SPECTROMETERS WITH FILTERED NOISE FIELDS  

EPA Science Inventory

Two ion trap mass spectrometers and direct air sampling interfaces are being evaluated in the laboratory for monitoring toxic air pollutants in real time. he mass spectrometers are the large, laboratory-based Finnigan MAT ion trap (ITMS) and the compact, field-deployable Teledyne...

59

Fully automated micro- and nanoscale one- or two-dimensional high-performance liquid chromatography system for liquid chromatography–mass spectrometry compatible with non-volatile salts for ion exchange chromatography  

Microsoft Academic Search

A one- or two-dimensional high performance liquid chromatography system for electrospray ionization mass spectrometers has been developed that is optimized for ion exchange and reversed phase separations. A unique and simple valve configuration permits the use of a variety of non-volatile salts; ammonium sulfate was used in an example of strong cation exchange separations. The system was designed and evaluated

Junichi Masuda; Dawn M. Maynard; Masayuki Nishimura; Teruhisa Ueda; Jeffrey A. Kowalak; Sanford P. Markey

2005-01-01

60

Characteristics of major secondary ions in typical polluted atmospheric aerosols during autumn in central Taiwan  

Microsoft Academic Search

In autumn of 2008, the chemical characteristics of major secondary ionic aerosols at a suburban site in central Taiwan were measured during an annually occurring season of high pollution. The semicontinuous measurement system measured major soluble inorganic species, including NH4+, NO3?, and SO42?, in PM10 with a 15 min resolution time. The atmospheric conditions, except for the influences of typhoons, were dominated

Guor-Cheng Fang; Shih-Chieh Lin; Shih-Yu Chang; Chuan-Yao Lin; Charles-C. K. Chou; Yun-Jui Wu; Yu-Chieh Chen; Wei-Tzu Chen; Tsai-Lin Wu

2011-01-01

61

Statistical models to predict the toxicity of major ions to Ceriodaphnia dubia, Daphnia magna and Pimephales promelas (fathead minnows)  

SciTech Connect

Toxicity of fresh waters with high total dissolved solids has been shown to be dependent on the specific ionic composition of the water. To provide a predictive tool to assess toxicity attributable to major ions, the authors tested the toxicity of over 2,900 ion solutions using the daphnids, Ceriodaphnia dubia and Daphnia magna, and fathead minnows (Pimephales promelas). Multiple logistic regression was used to relate ion composition to survival for each of the three test species. In general, relative ion toxicity was K{sup +} > HCO{sub 3}{sup {minus}} {approx} Mg{sup 2+} > Cl{sup {minus}} > SO{sub 4}{sup 2{minus}}; Na{sup +} and Ca{sup 2+} were not significant variables in the regressions, suggesting that the toxicity of Na{sup +} and Ca{sup 2+} salts was primarily attributable to the corresponding anion. For C. dubia and D. magna, toxicity of Cl{sup {minus}}, SO{sub 4}{sup 2{minus}}, and K{sup +} was reduced in solutions enriched with more than one cation. Final regression models showed a good quality of fit to the data (R{sup 2} = 0.767--0.861). Preliminary applications of these models to field-collected samples indicated a high degree of accuracy for the C. dubia model, while the D. magna and fathead minnow models tended to overpredict ion toxicity. Studies of oil and gas produced waters, irrigation drain waters, shale oil leachates, sediment pore waters, and industrial process waters have shown toxicity caused by elevated concentrations of common ions.

Mount, D.R. [Environmental Protection Agency, Duluth, MN (United States); Gulley, D.D. [Univ. of Wyoming, Laramie, WY (United States); Hockett, J.R.; Garrison, T.D. [ENSR Consulting and Engineering, Fort Collins, CO (United States); Evans, J.M. [Gas Research Inst., Chicago, IL (United States)

1997-10-01

62

Magma plumbing system of the 2000 eruption of Miyakejima volcano, Japan, deduced from volatile and major component contents of olivine-hosted melt inclusions  

Microsoft Academic Search

Chemical analyses of 56 olivine-hosted melt inclusions and their host olivines from the explosive eruption of Miyakejima volcano, Japan, on 18 August 2000 were carried out by electron probe micro analyzer and secondary ion mass spectrometry in order to investigate the magma plumbing system of the eruption. The bimodal olivine core composition, relatively small rims, and diffusion profiles of the

Genji Saito; Yuichi Morishita; Hiroshi Shinohara

2010-01-01

63

A Major Constituent of Brown Algae for Use in High-Capacity Li-Ion Batteries  

NASA Astrophysics Data System (ADS)

The identification of similarities in the material requirements for applications of interest and those of living organisms provides opportunities to use renewable natural resources to develop better materials and design better devices. In our work, we harness this strategy to build high-capacity silicon (Si) nanopowder-based lithium (Li)-ion batteries with improved performance characteristics. Si offers more than one order of magnitude higher capacity than graphite, but it exhibits dramatic volume changes during electrochemical alloying and de-alloying with Li, which typically leads to rapid anode degradation. We show that mixing Si nanopowder with alginate, a natural polysaccharide extracted from brown algae, yields a stable battery anode possessing reversible capacity eight times higher than that of the state-of-the-art graphitic anodes.

Kovalenko, Igor; Zdyrko, Bogdan; Magasinski, Alexandre; Hertzberg, Benjamin; Milicev, Zoran; Burtovyy, Ruslan; Luzinov, Igor; Yushin, Gleb

2011-10-01

64

Highly treated mine waters may require major ion addition before environmental release.  

PubMed

Mining operations often use passive and/or active water treatments to improve water quality prior to environmental release. Key considerations in choosing a treatment process include the extent to which the water quality is actually improved, and the potential residual environmental risks of the release of such water. However, there are few published studies concerning the environmental impacts of treated waste waters. This study used toxicity identification evaluation (TIE) methods to quantify and identify the "toxic" constituents of a highly-treated water (distillate) produced by brine concentration of a mining process water. Exposure of five freshwater species (Chlorella sp., Lemna aequinoctialis, Hydra viridissima, Moinodaphnia macleayi and Mogurnda mogurnda) to a concentration range of the distillate (0, 25, 50 and 100%) found that it was toxic to H. viridissima (50-100% effect when exposed to 100% distillate). TIE tests demonstrated that the effect wasn't due to residual ammonia (~1 mg L(-1)N) or trace organics, and unlikely to be due to manganese (Mn; 130-230 ?g L(-1)). Conversely, addition of 0.2 and 0.5 mg L(-1) calcium improved the growth rate of H. viridissima by 61 and 66%, respectively, while addition of calcium, sodium and potassium (0.5, 1.0 and 0.4 mg L(-1), respectively) to levels comparable to that in the local aquatic environment resulted in 100% recovery. Further assessment on the likelihood of residual metal toxicity indicated that Mn concentrations in the distillate were at levels that could inhibit the growth of H. viridissima. Ultimately, the results demonstrated that ion deficiency should be considered as a potential stressor in risk/impact assessments of the discharge of treated wastewaters, and these may need to be supplemented with the deficient ions to reduce environmental impacts. The findings have highlighted the need for water managers to consider the possibility of unintended environmental risks from the discharge of highly-treated wastewaters. PMID:23183225

Harford, Andrew J; Jones, David R; van Dam, Rick A

2013-01-15

65

Wet deposition of major ions in a rural area impacted by biomass burning emissions  

NASA Astrophysics Data System (ADS)

This work concerns the influence of industrialized agriculture in the tropics on precipitation chemistry. A total of 264 rain events were sampled using a wet-only collector in central São Paulo State, Brazil, between January 2003 and July 2007. Electroneutrality balance calculations (considering H +, K +, Na +, NH4+, Ca 2+, Mg 2+, Cl -, NO3-, SO42-, F -, PO43-, H 3CCOO -, HCOO -, CO42- and HCO3-) showed that there was an excess of cations (˜15%), which was attributed to the presence of unmeasured organic anion species originating from biomass burning and biogenic emissions. On average, the three ions NH4+, NO 3- and H + were responsible for >55% of the total ion concentrations in the rainwater samples. Concentrations (except of H +) were significantly higher ( t-test; P = 0.05), by between two to six-fold depending on species, during the winter sugar cane harvest period, due to the practice of pre-harvest burning of the crop. Principal component analysis showed that three components could explain 88% of the variance for measurements made throughout the year: PC1 (52%, biomass burning and soil dust resuspension); PC2 (26%, secondary aerosols); PC3 (10%, road transport emissions). Differences between harvest and non-harvest periods appeared to be mainly due to an increased relative importance of road transport/industrial emissions during the summer (non-harvest) period. The volume-weighted mean (VWM) concentrations of ammonium (23.4 ?mol L -1) and nitrate (17.5 ?mol L -1) in rainwater samples collected during the harvest period were similar to those found in rainwater from São Paulo city, which emphasizes the importance of including rural agro-industrial emissions in regional-scale atmospheric chemistry and transport models. Since there was evidence of a biomass burning source throughout the year, it appears that rainwater composition will continue to be affected by vegetation fires, even after sugar cane burning is phased out as envisaged by recent São Paulo State legislation.

Coelho, Cidelmara H.; Allen, Andrew G.; Fornaro, Adalgiza; Orlando, Eduardo A.; Grigoletto, Tahuana L. B.; Campos, M. Lucia A. M.

2011-09-01

66

Seasonal fluxes of major ions to a high altitude cold alpine glacier  

NASA Astrophysics Data System (ADS)

A 13 m fimcore was recovered in April 1991 at Col du Dome (4250 m.a.s.l.), located below the Mont Blanc summit (Northern French Alps). The core spans a complete sequence of 3.5 years of high alpine precipitation, as indicated by the stratigraphic and the isotopic profiles. Subsamples were analysed for Na +, NH 4+, K +, Mg 2+, Ca 2+, Cl -, NO 3- and SO 42- using ion chromatography, and for H + or HCO 3- using a titration technique. In absence of alkaline Saharan dust, the snow is slightly acid (2-20 ? Eq l-1. All analysed ions show a sharply pronounced seasonal pattern, with concentrations, extremely low in winter, increasing in spring and reaching a maximum in summer. This picture supports the idea that in winter the high alpine sites are generally not affected by polluted air masses from lower altitudes, whereas during spring and summer, vertical convective transport significantly affects the highest sites located well above 4000 m a.s.l. The lowest impurity levels of alpine winter snow are comparable with central Greenland values, suggesting that at this time, and just in opposite to what occurs in the Arctic, the highest alpine regions are representative of the continental free troposphere. Annual and seasonal deposition fluxes are calculated. In order to assess the spatial representativeness of these results, a comparison is made with similar records obtained from a 10m firncore recovered in summer 1991, at the low accumulation site Colle Gnifetti (4450 m.a.s.l.) located in the Swiss Alps, 80 km east of Col du Dôme. An excellent agreement is found between the overall mean isotopic and chemical composition of the two firncores, suggesting that, since clean winter snow is well preserved at Col du Dome, this site is presumably more influenced by precipitation during summer. Finally, the attractive perspectives for deep drilling in the Mont Blanc area are assessed, and the merits of making use of both sites, where comparable and complementary information can be obtained, are outlined.

Maupetit, F.; Wagenbach, D.; Weddeling, P.; Delmas, R. J.

67

Ambient orchard volatiles from California almonds  

Microsoft Academic Search

The volatile emissions of various plant parts of almonds have been studied via various techniques in the past. These analyses have typically been performed on single cultivars and hence may not be representative of the volatiles found in an entire almond orchard. Recent reports suggest some almond volatiles exhibit semiochemical activities for the navel orangeworm (NOW), a major insect pest

John J. Beck; Bradley S. Higbee; Wai S. Gee; Klaus Dragull

2011-01-01

68

Groundwater quality in Scotland: major ion chemistry of the key groundwater bodies.  

PubMed

Groundwater in Scotland is, for the most part, weakly to moderately mineralised and dominated by the Ca and HCO3 ions. The aquifer systems are almost entirely unconfined and most groundwater remains in contact with oxygen; some reducing groundwaters occur in deeper isolated cracks and joints within the many fractured bedrock aquifers such as Devonian sandstones. Groundwater depleted in oxygen is also common in the Coal Measures in the Midland Valley as a direct result of past coal and oil shale mining, when iron and other metals are taken into solution as the abandoned mine workings are allowed to flood. Low pH groundwaters are rare but do occur where calcite is absent in some basement rocks. Marine intrusion of coastal aquifers occurs locally in East Lothian and parts of Morayshire. Deeper circulating groundwaters are responsible for some of the more exotic spa waters, notably at Bridge of Earn near Perth. Nitrate contamination of groundwater is increasing in some areas, and is most prevalent in the south of Scotland. The Devonian aquifer in Fife and parts of the Permian sandstone aquifers of south-west Scotland are the worst affected. PMID:12169011

Robins, N S

2002-07-22

69

On the volatility of volatility  

NASA Astrophysics Data System (ADS)

The Chicago Board Options Exchange (CBOE) Volatility Index, VIX, is calculated based on prices of out-of-the-money put and call options on the S&P 500 index (SPX). Sometimes called the “investor fear gauge”, the VIX is a measure of the implied volatility of the SPX, and is observed to be correlated with the 30-day realized volatility of the SPX. Changes in the VIX are observed to be negatively correlated with changes in the SPX. However, no significant correlation between changes in the VIX and changes in the 30-day realized volatility of the SPX are observed. We investigate whether this indicates a mispricing of options following large VIX moves, and examine the relation to excess returns from variance swaps. The sense in which the term “mispricing” is used is discussed in the paper.

Hsu, Stephen D. H.; Murray, Brian M.

2007-07-01

70

A 20 Year Record of Major Ions in Aerosol and Rainwater from a Remote Location in the North Atlantic  

NASA Astrophysics Data System (ADS)

High frequency ambient air sampling conducted near continuously for a period of 20 years from 1989 to 2009 at the second highest point of land on the island of Bermuda has provided a valuable record of major ion (H+, Na+, K+, Ca2+, Mg2+, SO42-, Cl-, and NO3-) chemistry in aerosol and rainwater representative of the marine atmospheric boundary layer over the North Atlantic Ocean. Over this period the acidity of rainwater has shown a significant decrease from a monthly volume weighted mean pH 4.4 to pH 5.5, and the monthly volume weighted mean concentration of non-sea-salt sulfate in rainfall also exhibited a significant decrease over the same time period, suggesting a decrease in anthropogenic sources of acidifying species in rainwater. The long term record of major ion constituents in rainwater and in aerosol are presented, and relationships between the chemical constituents and regional seasonal meteorology are analyzed and discussed.

Peters, A.

2013-12-01

71

One-year observations of size distribution characteristics of major aerosol constituents at a coastal receptor site in Hong Kong - Part 1: Inorganic ions and oxalate  

NASA Astrophysics Data System (ADS)

Size distribution data of major aerosol constituents are essential in source apportioning of visibility degradation, testing and verification of air quality models incorporating aerosols. We report here 1-year observations of mass size distributions of major inorganic ions (sulfate, nitrate, chloride, ammonium, sodium, potassium, magnesium and calcium) and oxalate at a coastal suburban receptor site in Hong Kong, China. A total of 43 sets of size-segregated samples in the size range of 0.056-18 ?m were collected from March 2011 to February 2012. The size distributions of sulfate, ammonium, potassium and oxalate were characterized by a dominant droplet mode with a mass mean aerodynamic diameter (MMAD) in the range of ~ 0.7-0.9 ?m. Oxalate had a slightly larger MMAD than sulfate on days with temperatures above 22 °C as a result of the process of volatilization and repartitioning. Nitrate was mostly dominated by the coarse mode but enhanced presence in fine mode was detected on winter days with lower temperature and lower concentrations of sea salt and soil particles. This data set reveals an inversely proportional relationship between the fraction of nitrate in the fine mode and product of the sum of sodium and calcium in equivalent concentrations and the dissociation constant of ammonium nitrate (i.e., (1/([Na+] + 2[Ca2+]) × (1/Ke')) when Pn_fine is significant (> 10%). The seasonal variation observed for sea salt aerosol abundance, with lower values in summer and winter, is possibly linked with the lower marine salinities in these two seasons. Positive matrix factorization was applied to estimate the relative contributions of local formation and transport to the observed ambient sulfate level through the use of the combined data sets of size-segregated sulfate and select gaseous air pollutants. On average, the regional/super-regional transport of air pollutants was the dominant source at this receptor site, especially on high-sulfate days while local formation processes contributed approximately 30% of the total sulfate. This work provides field-measurement-based evidence important for understanding both local photochemistry and regional/super-regional transport in order to properly simulate sulfate aerosols in air quality models.

Bian, Q.; Huang, X. H. H.; Yu, J. Z.

2014-09-01

72

Application of ion-implantation for improved non-volatile resistive random access memory (ReRAM)  

NASA Astrophysics Data System (ADS)

Resistive switching in transition metal oxides is believed to be controlled by the migration of oxygen vacancies and many interesting device structures employ substoichiometric oxide layers as a source of these active defects. However, the growth of thin (˜10 nm) oxide/suboxide heterostructures (e.g. HfO2/HfOx or Ta2O5/TaOx) is difficult using conventional film deposition techniques. In this study, ion-implantation is shown to provide an alternative means of synthesizing such structures, with results reported for Ta2O5/TaOx heterostructures fabricated by oxygen-implantation of Ta. The electrical properties of the fabricated heterostructures are discussed with reference to the physical structure of the samples determined from transmission electron microscopy and X-ray photoelectron spectroscopy.

Elliman, R. G.; Saleh, M. S.; Kim, T.-H.; Venkatachalam, D. K.; Belay, K.; Ruffell, S.; Kurunczi, P.; England, J.

2013-07-01

73

Electron impact and chemical ionization mass spectral analysis of a volatile uranyl derivative  

SciTech Connect

Quadrupole mass spectral analysis of the volatile uranium ligand complex bis (1,1,1,5,5,5-hexafluoro-2,4-pentanedionato) dioxouranium-di-n-butyl sulfoxide is described utilizing electron impact (EI) and methane chemical ionization (CI) ion sources. All major ions are tentatively identified and the potential usefulness of this complex for determining uranium isotope /sup 235/U//sup 238/U abundance is demonstrated.

Reutter, D.J.; Hardy, D.R.

1981-01-01

74

87Sr/86Sr and major ion composition of rainwater of Ahmedabad, India: Sources of base cations  

NASA Astrophysics Data System (ADS)

Rainwater samples from Ahmedabad, an urban site in India are analysed for their chemical composition and Sr isotopic ratio. Dominance of Ca in the cation budget indicates its importance in the acid neutralization whereas SO4 and NO3 dominate the anion budget. The major ion concentrations measured in this study are on the lower side of the range reported in the previous study (Rastogi and Sarin, 2007) from the same site. Na and Cl show very good correlation with ratio similar to the seawater ratio, implying their marine origin. Na concentration in these samples has been used as a proxy to calculate the non sea salt fraction of other major ions. Non sea salt Ca and Mg vary from 99.0% to 99.6% and 24.6% to 89.1% of the measured Ca and Mg respectively whereas non sea salt component of SO4 and HCO3 contribute 84.3% to 98.9% and 99.1% to 99.9% respectively. Sr concentrations in these rainwaters vary from 32 to 191 nM and 87Sr/86Sr ranges from 0.70878 to 0.71027. Sr concentration shows a very good correlation (coefficient 0.93) with the non-sea salt component of Ca and Mg indicating their continental sources and having similar provenances. Carbonates and basalts seem to contribute significantly to dissolved base cations of the rainwaters. The basalts from Deccan region, which is isotopically indistinguishable from the African basalts and the silicate and carbonates from African region along with the sediments from the Ganga plain (which is originated from the Himalayan lithologies) could be potential dust sources for this particular site. The sources of dissolved base cations deduced from Sr isotope composition of the rainwaters are consistent with wind back trajectory data obtained from NOAA HYSPLIT model.

Chatterjee, Jayati; Singh, Sunil Kumar

2012-12-01

75

Use of reconstituted waters to evaluate effects of elevated major ions associated with mountaintop coal mining on freshwater invertebrates.  

PubMed

In previous laboratory chronic 7-d toxicity tests conducted with the cladoceran Ceriodaphnia dubia, surface waters collected from Appalachian sites impacted by coal mining have shown toxic effects associated with elevated total dissolved solids (TDS). The objective of the present study was to evaluate the effects of elevated major ions in chronic laboratory tests with C. dubia (7-d exposure), a unionid mussel (Lampsilis siliquoidea; 28-d exposure), an amphipod (Hyalella azteca; 28-d exposure), and a mayfly (Centroptilum triangulifer; 35-d exposure) in 3 reconstituted waters designed to be representative of 3 Appalachian sites impacted by coal mining. Two of the reconstituted waters had ionic compositions representative of alkaline mine drainage associated with mountaintop removal and valley fill-impacted streams (Winding Shoals and Boardtree, with elevated Mg, Ca, K, SO?, HCO?), and a third reconstituted water had an ionic composition representative of neutralized mine drainage (Upper Dempsey, with elevated Na, K, SO?, and HCO?). The waters with similar conductivities but, with different ionic compositions had different effects on the test organisms. The Winding Shoals and Boardtree reconstituted waters were consistently toxic to the mussel, the amphipod, and the mayfly. In contrast, the Upper Dempsey reconstituted water was toxic to the mussel, the amphipod, and the cladoceran but was not toxic to the mayfly. These results indicate that, although elevated TDS can be correlated with toxicity, the specific major ion composition of the water is important. Moreover, the choice of test organism is critical, particularly if a test species is to be used as a surrogate for a range of faunal groups. PMID:24243594

Kunz, James L; Conley, Justin M; Buchwalter, David B; Norberg-King, Teresa J; Kemble, Nile E; Wang, Ning; Ingersoll, Christopher G

2013-12-01

76

The Income Volatility See-Saw: Implications for School Lunch  

Microsoft Academic Search

Income volatility challenges the effectiveness of the safety net that USDA food assistance programs provide low-income families. This study examines income volatility among households with children and the implications of volatility for eligibility in the National School Lunch Program (NSLP). The results show that income volatility was higher for successively lower income groups and that the major determinants of changes

Constance Newman

2006-01-01

77

Chemosystematic analyses of Gingidia volatiles.  

PubMed

The leave volatiles of six Gingidia species from New Zealand and Australia and the seed volatiles of G. grisea were characterized by solid-phase microextraction (SPME)-GC/MS analysis. This technique, using a small quantity of samples and automated extraction, gave repeatable results, with maximum sensitivity for medium volatility compounds. The major monoterpenes among the volatiles, i.e., ?-phellandrene (4), limonene (6), and ?-terpinene (5), and phenylpropanoids, i.e., estragole (3), (E)-anethole (7), and myristicin (1), showed to be useful chemotaxonomic markers. For G. grisea leaves and seeds, similar compositions were detected, characterized by high contents of 4. As leaves were more readily available for study than seeds, they were used for further investigations. The G. grisea leaf volatiles showed infraspecific variation in the ratio of 4/5 between and within sites of collection. The G. montana leaf volatiles also showed infraspecific variation, with high contents of 3 at one site and high contents of 7 at another. The SPME-GC/MS analysis of G. montana herbarium voucher specimens resulted in the identification of further chemotypes for this species. The volatiles of the G. amphistoma samples were all dominated by 7 and those of the G. haematitica samples were rich in 5. Moreover, single plants of two Australian Gingidia species were analyzed; the volatiles of G. harveyana showed high concentrations of 5 and 7, whereas those of G. rupicola were dominated by 5 and 1. PMID:24327443

Sansom, Catherine E; Heenan, Peter B; Perry, Nigel B; Smallfield, Bruce M; van Klink, John W

2013-12-01

78

Quantitative Analysis of Isomeric Volatile Organic Compounds in a Northern Hardwood Forest by Proton Transfer Reaction Linear Ion Trap (PTR-LIT) Mass Spectrometry  

NASA Astrophysics Data System (ADS)

Several low molecular weight, isomeric volatile organic compounds (VOCs) occur in the atmosphere in the low ppb to ppt range, including methyl vinyl ketone (MVK) and (MACR) from isoprene oxidation, and aerosol precursor monoterpenes and sesquiterpenes. Although proton transfer reaction mass spectrometry (PTR- MS) quantifies VOCs with low ppt limits of detection (LOD), it cannot differentiate isomers or isobaric molecules. A proton transfer reaction - linear ion trap (PTR-LIT) mass spectrometer was developed and utilized to quantify and distinguish isomers as well as test for interferants by allowing for MSn experiments while retaining LOD in the 100 ppt range for most compounds. The PTR-LIT was deployed at the PROPHET tower site at the University of Michigan Biological Station (UMBS) from July to mid-August 2008 to sample air above a mixed deciduous/coniferous forest canopy. The extended capabilities of the PTR-LIT were used to address local ozone formation from the oxidation of isoprene by monitoring speciated MVK and MACR. Good agreement existed between [MVK+MACR] in MS1 mode and [MVK] + [MACR] in MS2 mode. Possible interferences at common masses were directly addressed by comparing the MS2 spectra of atmospheric masses to those of standards. Aerosol formation and size distribution data were compared to VOC oxidation. In particular isoprene oxidation was monitored by using MVK, MACR, and glyoxal, a fifth generation oxidation product. Furthermore, total monoterpene concentration was monitored and oxidation rates were calculated. Finally, total sesquiterpenes were not observed above the limit of detection making them an unlikely source for either aerosol growth or the missing OH reactivity previously observed at UMBS.

Mielke, L. H.; Slade, J.; Alaghmand, M.; Galloway, M.; Kammrath, A.; Keutsch, F.; Bertman, S.; Carroll, M.; Stevens, P.; Dusanter, S.; Erickson, D.; McLuckey, S. A.; Shepson, P. B.

2008-12-01

79

HCO+ Observations toward Comet Hale-Bopp (C/1995 O1): Ion-Molecule Chemistry and Evidence for a Volatile Secondary Source  

NASA Astrophysics Data System (ADS)

Several millimeter-wave transitions of HCO+ have been detected toward comet Hale-Bopp (C/1995 O1) using the Arizona Radio Observatory 12 m telescope. The J=2-->1 transition at 178 GHz was observed toward the comet nucleus near perihelion on 1997 March 10 and 20, as well as the J=3-->2 transition at 268 GHz on 1997 March 9, with angular resolutions of 36" and 23", respectively. These data all show a slight velocity shift (~1.2 km s-1) from the nominal comet velocity, and the J=3-->2 profile is asymmetric with a redshifted wing. These differences likely arise from ion acceleration by the solar wind. A rotational diagram analysis of the data yielded a column density of 1.1×1012 cm-2 for HCO+ in Hale-Bopp, which corresponds to an average number density of 36 cm-3. The data taken on March 9 show a second velocity component redshifted by 7.0+/-0.6 km s-1, which is considerably weaker than the main feature and appears to have a counterpart in the HNC, J=3-->2 data, observed within an hour of the HCO+ measurements. The velocity difference between the main and secondary emission lines deprojected onto the extended solar radius vector is ~10 km s-1 for both HCO+ and HNC, and the weak-to-strong line intensity ratios (~5%) are identical to within observational errors, suggesting a common high-velocity volatile secondary source. A plausible model that may account for the redshifted velocity components is a comoving, localized debris field of submicron refractory grains accelerated by solar radiation pressure located ~105-106 km from the nucleus. The parent material of the weaker redshifted HNC and HCO+ lines may be predominately complex organic polymers. An examination of the production rates for HCO+ suggests that the reaction H2+CO+ is likely to be an important route to this ion in the outer coma beyond the collisionopause, where it has its peak abundance.

Milam, S. N.; Savage, C.; Ziurys, L. M.; Wyckoff, S.

2004-11-01

80

Chemical erosion in the eastern Himalaya: Major ion composition of the Brahmaputra and ? 13C of dissolved inorganic carbon  

NASA Astrophysics Data System (ADS)

Major ion composition of waters, ? 13C of its DIC (dissolved inorganic carbon), and the clay mineral composition of bank sediments in the Brahmaputra River System (draining India and Bangladesh) have been measured to understand chemical weathering and erosion and the factors controlling these processes in the eastern Himalaya. The time-series samples, collected biweekly at Guwahati, from the Brahmaputra mainstream, were also analyzed for the major ion composition. Clay mineralogy and chemical index of alteration (CIA) of sediments suggest that weathering intensity is relatively poor in comparison to that in the Ganga basin. This is attributed to higher runoff and associated physical erosion occurring in the Brahmaputra basin. The results of this study show, for the first time, spatial and temporal variations in chemical and silicate erosion rates in the Brahmaputra basin. The subbasins of the Brahmaputra watershed exhibit chemical erosion rates varying by about an order of magnitude. The Eastern Syntaxis basin dominates the erosion with a rate of ˜300 t km -2 y -1, one of the highest among the world river basins and comparable to those reported for some of the basaltic terrains. In contrast, the flat, cold, and relatively more arid Tibetan basin undergoes much slower chemical erosion (˜40 t km -2 y -1). The abundance of total dissolved solids (TDS, 102-203 mg/L) in the time-series samples collected over a period of one year shows variations in accordance with the annual discharge, except one of them, cause for which is attributable to flash floods. Na* (Na corrected for cyclic component) shows a strong positive correlation with Si, indicating their common source: silicate weathering. Estimates of silicate cations (Na sil+K sil+Ca sil+Mg sil) suggest that about half of the dissolved cations in the Brahmaputra are derived from silicates, a proportion higher than that for the Ganga system. The CO 2 consumption rate due to silicate weathering in the Brahmaputra watershed is ˜6 × 10 5 moles km -2 y -1; whereas that in the Eastern Syntaxis subbasin is ˜19 × 10 5 moles km -2 y -1, similar to the estimates for some of the basaltic terrains. This study suggests that the Eastern Syntaxis basin of the Brahmaputra is one of most intensely chemically eroding regions of the globe; and that runoff and physical erosion are the controlling factors of chemical erosion in the eastern Himalaya.

Singh, Sunil K.; Sarin, M. M.; France-Lanord, Christian

2005-07-01

81

REDUCTION OF INGESTION EXPOSURE TO TRIHALOMETHANES DUE TO VOLATILIZATION. (R825362)  

EPA Science Inventory

Ingestion of tap water is one of the principal exposure pathways for disinfection byproducts (DBPs). One major class of DBPs, trihalomethanes (THM), are highly volatile, and volatilization will tend to lower ingestion exposures. This study quantifies volatilization...

82

Spatial Concentration Fields of Trace Elements and Major Ions Over a Large and Highly Inaccessible Area of Antarctica  

NASA Astrophysics Data System (ADS)

Over-snow traverses, such as those conducted by the International Trans-Antarctic Scientific Expedition (ITASE), provide the data needed at a high enough spatial and temporal resolution to form a more accurate assessment of the regional chemical and climate differences between deep core sites. This study focuses on a collection of snow pits and surface snow samples collected along the 2002/03 (ITASE-02), 2003/04 (ITASE- 03), 2006/07 (ITASE-06), and 2007/08 (ITASE-07) US ITASE traverses - total distance >5000 km. The ITASE-02 traverse started from Byrd Station, West Antarctica, and progressed southward, ultimately ending at the South Pole. The ITASE-03 traverse began at the South Pole and proceeded over the interior of East Antarctica to the Automated Geophysical Observatory number 4 (AGO4). From AGO4 the traverse traveled northward along the Transantarctic Mountain seismic sensor line, passing through the area known as Megadunes, and finishing up at Taylor Dome. The ITASE-06 traverse began at Taylor Dome and traveled in a southwesterly direction ending up approximately 300 km inland from Byrd Glacier mouth. The ITASE-07 traverse began where the ITASE-06 traverse left off, and continued in a southwesterly direction for 200 km before heading directly south and ending up at South Pole. Several snow pits were collected along the traverses and >250 surface snow samples were collected every ~20-50 km. All samples were analyzed using an ion chromatograph for their soluble major ion content (Na, K, Mg, Ca, Cl, NO3, SO4). Additionally, the surface snow samples were all analyzed for their trace element content (Sr, Cd, Cs, Ba, La, Ce, Pr, Pb, Bi, U, As, Al, Ti, V, Cr, Mn, Fe, Co, Cu, Zn) using inductively coupled plasma mass spectrometry. Snow pit data indicate summer concentration values for most of the surface snow samples. However, the seasonality of the surface snow samples is most uncertain between AGO4 and the Megadunes. The ice sheet surface around the Megadunes area is most likely composed of redistributed or reworked (probably through ablation processes) snow. The process of surface ablation has the effect of concentrating chemistry on the surface. Summer concentrations of several trace elements in West Antarctica are below detection limits. However, there are high concentrations around the South Pole and Megadunes areas. These concentration variations may be a consequence of chemical and/or precipitation differences between the traverse years.

Dixon, D. A.; Mayewski, P. A.; Sneed, S. B.; Handley, M. J.; Maasch, K. A.; Kreutz, K. J.; Hamilton, G. S.; Carleton, A. M.

2008-12-01

83

Estimates of average major ion concentrations in bulk precipitation at two high-altitude sites near the continental divide in Southwestern Colorado  

USGS Publications Warehouse

The composition of bulk precipitation from two high-altitude sites, established in 1971 near the Continental Divide in southwestern Colorado, has been monitored by season during the past decade. Calcium ions are the predominant cationic species; sulfate is the major anionic constituent. Bulk precipitation major ion concentrations exhibit log-normal distributions. Representative mean and standard deviation values for the major inorganic ionic species present in bulk precipitation have been calculated for three years of consecutive seasons. Standard deviations for all species, except nitrate, are similar. For two years of data grouped into quarters, deviations from mean values fall well within the plus or minus two standard deviation limit. There does not seem to be a systematic deviation from the mean concentration values, with respect to either ionic component or season.

Reddy, M.M.; Claassen, H.C.

1985-01-01

84

Major ions, nutrients, and trace elements in the Mississippi River near Thebes, Illinois, July through September 1993  

USGS Publications Warehouse

Extensive flooding in the upper Mississippi River Basin during summer 1993 had a significant effect on the water quality of the Mississippi River. To evaluate the change in temporal distribution and transport of dissolved constituents in the Mississippi River, six water samples were collected by a discharge-weighted method from July through September 1993 near Thebes, Illinois. Sampling at this location provided water-quality information from the upper Mississippi, the Missouri, and the Illinois River Basins. Dissolved major constituents that were analyzed in each of the samples included bicarbonate, calcium (Ca), carbonate (CO3), chloride (C1), dissolved organic carbon, magnesium (Mg), potassium (K), silica (SiO2) , sodium (Na), and sulfate (SO4). Dissolved nutrients included ammonium ion (NH4), nitrate (NO3), nitrite (NO2), and orthophosphate (PO4). Dissolved trace elements included aluminum (A1), arsenic (As), barium (Ba), boron (B), beryllium (Be), bromide (Br), cadmium (Cd), chromium (Cr), cobalt, (Co), copper (Cu), fluoride (F), iron (Fe), lead, lithium (Li), manganese (Mn), mercury (Hg), molybdenum (Mo), nickel (Ni), strontium (Sr), thallium, uranium (U), vanadium (V), and zinc (Zn). Other physical properties of water that were measured included specific conductance, pH and suspended-sediment concentration (particle size, less than 63 micrometers). Results of this study indicated that large quantifies of dissolved constituents were transported through the river system. Generally, pH, alkalinity, and specific conductance and the concentrations of B, Br, Ca, C1, Cr, K, Li, Mg, Mo, Na, SO4, Sr, U, and V increased as water discharge decreased, while concentrations of F, Hg, and suspended sediment sharply decreased as water discharge decreased after the crest of the flood. Concentrations of other constituents, such as A1, As, Ba, Be, Co, Cu, Ni, NO3, NO2, NH4, PO 4, and SiO2, varied with time as discharge decreased after the crest of the flood. For most constituents, the load transported during floods generally is much greater than that transported during low-flow conditions. However, for Cd, Cr, Fe, Mn, V, and Zn, loads increased substantially as water discharge decreased after the crest of the flood.

Taylor, Howard E.; Antweiler, Ronald C.; Brinton, Terry I.; Roth, David A.; Moody, John A.

1994-01-01

85

Comparisons between ion distributions retrieved from ENA images of the ring current and contemporaneous, multipoint ion measurements recorded in situ during the major magnetic storm of 15 May 2005  

Microsoft Academic Search

The Neutral Atom Detector Unit (NUADU) aboard the TC-2 spacecraft recorded energetic neutral atom (ENA) image data for >3 h during part of the main and recovery phases of a major magnetic storm on 15 May 2005. A custom designed, constrained linear inversion method was applied to retrieve ring current ion distributions in the ENA records out to L =

L. Lu; S. McKenna-Lawlor; S. Barabash; P. C. Brandt; J. Balaz; Z. X. Liu; Z. H. He; G. D. Reeves

2010-01-01

86

Geochemistry of the upper Han River basin, China. 2: Seasonal variations in major ion compositions and contribution of precipitation chemistry to the dissolved load.  

PubMed

A total of 252 water samples were collected from 42 sites across the upper Han River basin during the time period from 2005-2006. Major ions (Cl(-), NO3(-), SO4(2-), HCO3(-), Na+, K+, Ca2+ and Mg2+), Si, water temperature, pH, EC and TDS were determined and consequently correlation matrix, analysis of variance, factor analysis and principal component analysis were performed in order to identify their seasonal variations and atmospheric inputs into river solutes. The results reveal that pH, EC, TDS, Cl(-), SO4(2-), HCO3(-), Ca2+ and Mg2+, K+ and Si generally tend to show the minimum compositions in months belong to the rainy season, while the dry season for NO3(-) and Na+. NO3(-), Mg2+ and Si have the maximum concentrations in months belong to the rainy season. By comparing the major ions relating to hydrological regime, NO3(-), contrary to other elements, has higher concentration in the rainy season. The overall water quality is non-polluted, while there are indications of enrichment of inorganic anions including NO3(-) causing water entrophication in the near future. The atmospheric inputs contribute to river solutes is limited with a mean inputs of approximate 1% in the basin. The understanding of the major ion dynamics would help water quality conservation in the basin for China's interbasin water transfer project. PMID:19523765

Li, Siyue; Zhang, Quanfa

2009-10-30

87

Identification of muscadine wine sulfur volatiles: pectinase versus skin-contact maceration.  

PubMed

Muscadine grapes ( Vitis rotundifolia ) are widely grown in the southern United States, as the more common Vitis vinifera cannot be cultivated due to Pierce's disease. There is interest to determine if certain cultivars can be used for good-quality wine production. This study compared the effect of pectolytic enzyme pretreatment with conventional skin-contact fermentation on Muscadine (Noble, Vitis rotundifolia ) wine major volatiles, aroma active volatiles, and volatile sulfur compounds (VSCs). Volatile composition, aroma activity, and VSCs in the initial juice and wine samples after 3 years were determined by gas chromatography in combination with mass spectrometry (GC-MS), olfactory detection (GC-O), and pulsed flame photometric detection (GC-PFPD). Forty-three nonethanol MS volatiles were common to all samples. Total ion chromatogram (TIC) MS peak area increased 91% in the skin-contact wines from the initial juice but only 24% in the enzyme-treated wine. Thirty-one VSCs were detected. Twenty-four sulfur volatiles were identified by matching their retention characteristics on polar and nonpolar columns with those of standards or MS spectrum matches. Six of these (sulfur dioxide, 1-propanethiol, 3-mercapto-2-pentanone, 3-mercapto-2-butanone, 2,8-epithio-cis-p-menthane, and 1-p-menthene-8-thiol) were reported for the first time in muscadine wine. Five additional VSCs were tentatively identified by matching standardized retention values with literature values, and two remain unidentified. Total sulfur peak areas increased 400% in the skin-contact wine and 560% in the enzyme-treated wine compared to the initial juice. There were 42 aroma-active volatiles in the initial juice, 48 in the skin-contact wine, and 66 in the enzyme-treated wine. Eleven aroma-active volatiles in the skin-contact wine and 16 aroma volatiles in the enzyme-treated wine appear to be due to sulfur volatiles. Pectolytic enzyme-treated wines contained less total volatiles but more sulfur and aroma-active volatiles than the traditional skin-contact wine. PMID:23289372

Gürbüz, Ozan; Rouseff, June; Talcott, Stephen T; Rouseff, Russell

2013-01-23

88

A Test of a Major-ion Toxicity Model to Predict the Toxicity of Coal Bed Methane Product Waters to Aquatic Biota  

NASA Astrophysics Data System (ADS)

Coal bed methane (CBM) accounts for about 7.5% of the total natural gas production in the United States, and the Powder River Basin (PRB) in Montana and Wyoming has recently become a major production area. During CBM extraction, a coal seam is partially de-watered to relieve hydraulic pressure, thus causing methane gas to desorb. Some of this water (called product water) is discharged on the land surface and allowed to run into local drainages in the PRB. Due to the massive amounts of product water being discharged (rates up to 64,000 L/day per well), studies are needed to examine the potential effects on aquatic organisms. Additionally, models to predict such effects would be useful regulatory screening tools. To that end, we tested the ability of a multivariate logistic regression model of the toxicity of major inorganic ions (i.e., Na+, K+, Ca2+, Mg2+, Cl-, HCO3-, SO42-) to predict the acute toxicity of CBM-related waters to two aquatic invertebrates (Ceriodaphnia dubia and Daphnia magna) and fathead minnows (Pimephales promelas). First, we entered water chemistry data for several CBM product and receiving waters from the PRB into the major-ion model. Then we compared the model's predicted survival to the survival of the three species in toxicity tests we had previously conducted with those waters. For the majority of CBM product water and stream water samples in which CBM product water constituted the entire flow of the stream, the major-ion model consistently under-predicted survival by >50%. Therefore, from a regulatory standpoint, this model is conservative for detecting toxicity of CBM product waters (i.e., it over-predicts toxicity). Although the model appeared to be an excellent predictor of survival for receiving waters that contained no inputs from CBM processing (i.e., the difference between predicted and observed survival was <=10%), the majority of those cases were inconclusive tests of the model because the predicted and observed survival were either both >90% or both <10%. In such cases, it was not possible to test the accuracy of the regression coefficients in the major-ion model.

Forbes, M. B.; Meyer, J. S.

2003-12-01

89

Characterization of natural scale deposits formed in southern Algeria groundwater. Effect of its major ions on calcium carbonate precipitation  

Microsoft Academic Search

The structure and morphology of natural scale deposits formed in Ouargla's pipelines, southern Algeria, were characterized by using ICP-AES, X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy and energy dispersive spectroscopy (SEM\\/EDS). The precipitate is mainly composed of CaCO3 with the prevalence of the aragonite phase. Groundwater of this region was also analyzed. The principal ions identified are Ca2+, Mg2+,

Rachid Ketrane; Lydia Leleyter; Fabienne Baraud; Marc Jeannin; Otavio Gil; Boualem Saidani

2010-01-01

90

Atmospheric trace element and major ion concentrations over the eastern Mediterranean Sea: Identification of anthropogenic source regions  

NASA Astrophysics Data System (ADS)

Concentrations of elements and ions measured in aerosol samples collected from March 1992 to the end of December 1993 were investigated to identify source regions affecting chemical composition of aerosols in the eastern Mediterranean atmosphere. Collected samples were analyzed for approximately 40 elements and ions using a combination of atomic absorption spectrometry, instrumental neutron activation analysis, ion chromatography and colorimetry. Statistical techniques, such as enrichment factors and a non-parametric bootstrapped potential source contribution function, were applied on the data set to determine main source types and source regions of anthropogenic particles in the eastern Mediterranean basin. Source regions of two previously defined anthropogenic components, namely a long-range transported component and a local pollution component, were identified. The main source areas for pollutants reaching the eastern Mediterranean basin were determined as southern and western parts of Turkey, central and eastern regions of Ukraine, east of Belarus, Greece, Georgia, Romania, coastal areas along France and Spain and coastal areas around the Black Sea, Russia. More distant source regions in the South of UK and Sweden, the central part of Algeria, the northeastern part of Turkey, Russia, Germany, Hungary, Czech Republic, Bosnia and Herzegovina, and coastal areas of Egypt, Israel and Italy do affect aerosol composition in the eastern Mediterranean, but transport from these regions cannot account for the highest 20% of the measured pollutant concentrations.

Güllü, Gülen; Do?an, Güray; Tuncel, Gürdal

91

Establishing the occurrence of major and minor glucosinolates in Brassicaceae by LC-ESI-hybrid linear ion-trap and Fourier-transform ion cyclotron resonance mass spectrometry.  

PubMed

Glucosinolates (GLSs) are sulfur-rich plant secondary metabolites which occur in a variety of cruciferous vegetables and among various classes of them, genus Brassica exhibits a rich family of these phytochemicals at high, medium and low abundances. Liquid chromatography (LC) with electrospray ionization in negative ion mode (ESI-) coupled to a hybrid quadrupole linear ion trap (LTQ) and Fourier transform ion cyclotron resonance mass spectrometer (FTICRMS) was employed for the selective and sensitive determination of intact GLSs in crude sample extracts of broccoli (Brassica oleracea L. Var. italica), cauliflower (B. oleracea L. Var. Botrytis) and rocket salad (Eruca sativa L.) with a wide range of contents. When LTQ and FTICR mass analyzers are compared, the magnitude of the limit of detection was ca. 5/6-fold lower with the FTICR MS. In addition, the separation and detection by LC-ESI-FTICR MS provides a highly selective assay platform for unambiguous identification of GLSs, which can be extended to lower abundance (minor) GLSs without significant interferences of other compounds in the sample extracts. The analysis of Brassicaceae species emphasized the presence of eight minor GLSs, viz. 1-methylpropyl-GLS, 2-methylpropyl-GLS, 2-methylbutyl-GLS, 3-methylbutyl-GLS, n-pentyl-GLS, 3-methylpentyl-GLS, 4-methylpentyl-GLS and n-hexyl-GLS. The occurrence of these GLSs belonging to the saturated aliphatic side chain families C(4), C(5) and C(6), presumably formed by chain elongation of leucine, homoleucine and dihomoleucine as primary amino acid precursors, is described. Based on their retention behavior and tandem MS spectra, all these minor compounds occurring in plant extracts of B. oleracea L. Var. italica, B. oleracea L. Var. Botrytis and E. sativa L. were tentatively identified. PMID:22030302

Lelario, Filomena; Bianco, Giuliana; Bufo, Sabino A; Cataldi, Tommaso R I

2012-01-01

92

Transactions, Volume, and Volatility  

Microsoft Academic Search

We show that the positive volatility-volume relation documented by numerous researchers actually reflects the positive relation between volatility and the number of transactions. Thus, it is the occurrence of transactions per se, and not their size, that generates volatility; trade size has no information beyond that contained in the frequency of transactions. Our results suggest that theoretical research needs to

Charles M. Jones; Gautam Kaul; Marc L Lipson

1994-01-01

93

Biogeochemical processes controlling the mobility of major ions and trace metals in aquitard sediments beneath an oil sand tailing pond: laboratory studies and reactive transport modeling.  

PubMed

Increased production and expansion of the oil sand industry in Alberta are of great benefit to the economy, but they carry major environmental challenges. The volume of fluid fine tailings requiring storage is 840×10(6) m(3) and growing, making it imperative that we better understand the fate and transport of oil sand process-affected water (OSPW) seepage from these facilities. Accordingly, the current study seeks to characterize both a) the potential for major ion and trace element release, and b) the principal biogeochemical processes involved, as tailing pond OSPW infiltrates into, and interacts with, underlying glacial till sediments prior to reaching down gradient aquifers or surface waters. Objectives were addressed through a series of aqueous and solid phase experiments, including radial diffusion cells, an isotope analysis, X-ray diffraction, and sequential extractions. The diffusion cells were also simulated in a reactive transport framework to elucidate key reaction processes. The experiments indicate that the ingress and interaction of OSPW with the glacial till sediment-pore water system will result in: a mitigation of ingressing Na (retardation), displacement and then limited precipitation of exchangeable Ca and Mg (as carbonates), sulfate reduction and subsequent precipitation of the produced sulfides, as well as biodegradation of organic carbon. High concentrations of ingressing Cl (~375 mg L(-1)) and Na (~575 mg L(-1)) (even though the latter is delayed, or retarded) are expected to migrate through the till and into the underlying sand channel. Trace element mobility was influenced by ion exchange, oxidation-reduction, and mineral phase reactions including reductive dissolution of metal oxyhydroxides - in accordance with previous observations within sandy aquifer settings. Furthermore, although several trace elements showed the potential for release (Al, B, Ba, Cd, Mn, Pb, Si, Sr), large-scale mobilization is not supported. Thus, the present results suggest that in addition to the commonly cited naphthenic acids, remediation of OSPW-impacted groundwater will need to address high concentrations of major ions contributing to salinization. PMID:23727691

Holden, A A; Haque, S E; Mayer, K U; Ulrich, A C

2013-08-01

94

Glycine betaine and potassium ion are the major compatible solutes in the extremely halophilic methanogen Methanohalophilus strain Z7302.  

PubMed Central

Methanohalophilus strain Z7302 was previously isolated from a hypersaline environment and grows over a range of NaCl concentrations from 1.7 to 4.4 M. We examined the relationships between cell growth rate, cell volume, and intracellular solute concentrations with increasing salinity. This extremely halophilic methanogen synthesized three zwitterionic compounds, beta-glutamine, N epsilon-acetyl-beta-lysine, and glycine betaine, and also accumulated potassium ion as compatible solutes to balance the external and internal osmotic pressures. Potassium and glycine betaine were the predominant compatible solutes when Methanohalophilus strain Z7302 was grown at high external NaCl concentrations and approached intracellular levels of 3 and 4 M, respectively. PMID:1429470

Lai, M C; Gunsalus, R P

1992-01-01

95

Effect of ?-irradiation on the volatile compounds of medicinal herb, Paeoniae Radix  

NASA Astrophysics Data System (ADS)

A study was carried out to find the effect of ?-irradiation on contents of volatile compounds from medicinal herb, Paeoniae Radix ( Paenia albiflora Pallas var. trichocarpa Bunge). The volatile compounds of control, 1, 3, 5 and 10 kGy irradiated samples were extracted by simultaneous steam distillation and extraction (SDE) method and analyzed by gas chromatograph-mass spectrometer. The major volatile compounds were paeonol, ( E)-carveol, ( E, E)-2,4-octadienal, methyl salicylate, myrtanol and eugenol acetate. Volatile compounds belonging to chemical classes of acids, alcohols, aldehydes, esters, hydrocarbons and miscellaneous were identified in all experimental samples. The types of volatile compounds in irradiated samples were similar to those of non-irradiated sample and the concentrations of these compounds differed between treatments. 1,3-Bis (1,1-dimethylethyl)-benzene was identified by using the selected ion monitoring (GC/MS-SIM) mode. The concentration of this compound increased with the increase of irradiation dose level. These results suggest that it could be used as the base data for the effect of ?-irradiation on medicinal herb.

Shim, Sung-Lye; Hwang, In-Min; Ryu, Keun-Young; Jung, Min-Seok; Seo, Hye-young; Kim, Hee-Yeon; Song, Hyun-Pa; Kim, Jae-Hun; Lee, Ju-Woon; Byun, Myung-Woo; Kwon, Joong-Ho; Kim, Kyong-Su

2009-07-01

96

Current status of fluoride volatility method development  

SciTech Connect

The Fluoride Volatility Method is based on a separation process, which comes out from the specific property of uranium, neptunium and plutonium to form volatile hexafluorides whereas most of fission products (mainly lanthanides) and higher transplutonium elements (americium, curium) present in irradiated fuel form nonvolatile tri-fluorides. Fluoride Volatility Method itself is based on direct fluorination of the spent fuel, but before the fluorination step, the removal of cladding material and subsequent transformation of the fuel into a powdered form with a suitable grain size have to be done. The fluorination is made with fluorine gas in a flame fluorination reactor, where the volatile fluorides (mostly UF{sub 6}) are separated from the non-volatile ones (trivalent minor actinides and majority of fission products). The subsequent operations necessary for partitioning of volatile fluorides are the condensation and evaporation of volatile fluorides, the thermal decomposition of PuF{sub 6} and the finally distillation and sorption used for the purification of uranium product. The Fluoride Volatility Method is considered to be a promising advanced pyrochemical reprocessing technology, which can mainly be used for the reprocessing of oxide spent fuels coming from future GEN IV fast reactors.

Uhlir, J.; Marecek, M.; Skarohlid, J. [UJV - Nuclear Research Institute, Research Centre Rez, CZ-250 68 Husinec - Rez 130 (Czech Republic)

2013-07-01

97

Evaluation of fast volatile analysis for detection of Botrytis cinerea infections in strawberry.  

PubMed

Grey mold (Botrytis cinerea) is one of the major phytopathogens causing serious losses during strawberry postharvest and storage. B. cinerea-host interaction affect emissions of volatile compounds during infection resulting in a characteristic earthy, mushroom odor. Therefore, the objective of this study was to evaluate two analytical techniques based on fast volatile analysis on their performance for monitoring evolution and early detection of B. cinerea infections in strawberry. In a first experiment headspace multi-capillary column-ion mobility spectrometry (HS MCC-IMS) has been successfully used to evaluate development of strawberry aroma during shelflife. In a second experiment the same technique has been used to detect the degree of B. cinerea infection through changes in the volatile profile. Additionally, these samples were analyzed with headspace solid-phase-microextraction fast GC-MS (HS SPME fast GC-MS). Both HS MCC-IMS and HS SPME fast GC-MS could determine the changes in volatile composition as a function of the degree of B. cinerea infection as determined by an enzyme-linked immunosorbent assay (ELISA) and could be used to follow the evolution of infection. According to the ELISA data, some fruit were infected even without any symptoms and volatiles produced by the fungus may be overshadowed by the fruit volatiles. Therefore, both analytical techniques could not be used for early detection of B. cinerea infections. After identification of the volatile compounds and multivariate data analysis, potential biomarkers specific for B. cinerea were highlighted, being 3-methylbutanal, cis-4-decenal, 2-methyl-1-butanol, 2-methyl-1-propanol, 1-octen-3-one and 1-octen-3-ol. PMID:22986207

Vandendriessche, Thomas; Keulemans, Johan; Geeraerd, Annemie; Nicolai, Bart M; Hertog, Maarten L A T M

2012-12-01

98

Correlations in Price Changes and Volatility across International Stock Markets  

Microsoft Academic Search

The short-run interdependence of prices and price volatility across three major international stock markets is studied. Daily opening and closing prices of major stock indexes for the Tokyo, London, and New York stock markets are examined. The analysis utilizes the autoregressive conditionally heteroskedastic (ARCH) family of statistical models to explore these pricing relationships. Evidence of price volatility spillovers from New

Yasushi Hamao; Ronald W Masulis; Victor Ng

1990-01-01

99

Application of solid phase-microextraction (SPME) and electronic nose techniques to differentiate volatiles of sesame oils prepared with diverse roasting conditions.  

PubMed

Headspace volatiles of sesame oil (SO) from sesame seeds roasted at 9 different conditions were analyzed by a combination of solid phase microextraction (SPME)-gas chromatography/mass spectrometry (GC/MS), electronic nose/metal oxide sensors (MOS), and electronic nose/MS. As roasting temperature increased from 213 to 247 °C, total headspace volatiles and pyrazines increased significantly (P < 0.05). Pyrazines were major volatiles in SO and furans, thiazoles, aldehydes, and alcohols were also detected. Roasting temperature was more discrimination factor than roasting time for the volatiles in SO through the principal component analysis (PCA) of SPME-GC/MS, electronic nose/MOS, and electronic nose/MS. Electronic nose/MS showed that ion fragment 52, 76, 53, and 51 amu played important roles in discriminating volatiles in SO from roasted sesame seeds, which are the major ion fragments from pyrazines, furans, and furfurals. SO roasted at 213, 230, and 247 °C were clearly differentiated from each other on the base of volatile distribution by SPME-GC/MS, electronic nose/MOS, and electronic nose/MS analyses. Practical Application: The results of this study are ready to apply for the discriminating samples using a combinational analysis of volatiles. Not only vegetable oils prepared from roasting process but also any food sample possessing volatiles could be targets for the SPME-GC/MS and electronic nose assays. Contents and types of pyrazines in sesame seed oil could be used as markers to track down the degree of roasting and oxidation during oil preparation. PMID:21535659

Park, Min Hee; Jeong, Min Kyu; Yeo, JuDong; Son, Hee-Jin; Lim, Chae-Lan; Hong, Eun Jeung; Noh, Bong-Soo; Lee, JaeHwan

2011-01-01

100

Major ion chemistry and hydrochemical studies of groundwater of parts of Palar river basin, Tamil Nadu, India.  

PubMed

Groundwater is almost globally important for human consumption as well as for the support of habitat and for maintaining the quality of base flow to rivers, while its quality assessment is essential to ensure sustainable safe use of the resources for drinking, agricultural, and industrial purposes. In the current study, 50 groundwater samples were collected from parts of Palar river basin to assess water quality and investigate hydrochemical nature by analyzing the major cations (Ca, Mg, Na, K) and anions (HCO(3), Cl, F,SO(4), NO(3), PO(4),CO(3), HCO(3), and F) besides some physical and chemical parameters (pH, electrical conductivity, alkalinity, and total hardness). Also, geographic information system-based groundwater quality mapping in the form of visually communicating contour maps was developed using ArcGIS-9.2 to delineate spatial variation in physicochemical characteristics of groundwater samples. Wilcox classification and US Salinity Laboratory hazard diagram suggests that 52% of the groundwater fall in the field of C2-S1, indicating water of medium salinity and low sodium, which can be used for irrigation in almost all types of soil with little danger of exchangeable sodium. Remaining 48% is falling under C1-SI, indicating water of low salinity and low sodium. PMID:20886289

Dar, Mithas Ahmad; Sankar, K; Dar, Imran Ahmad

2011-05-01

101

Multivariate Stochastic Volatility  

Microsoft Academic Search

We provide a detailed summary of the large and vibrant emerging literature that deals with the multivariate modeling of conditional\\u000a volatility of financial time series within the framework of stochastic volatility. The developments and achievements in this\\u000a area represent one of the great success stories of financial econometrics. Three broad classes of multivariate stochastic\\u000a volatility models have emerged: one that

Siddhartha Chib; Yasuhiro Omori; Manabu Asai

2007-01-01

102

Food price volatility  

PubMed Central

The high food prices experienced over recent years have led to the widespread view that food price volatility has increased. However, volatility has generally been lower over the two most recent decades than previously. Variability over the most recent period has been high but, with the important exception of rice, not out of line with historical experience. There is weak evidence that grains price volatility more generally may be increasing but it is too early to say. PMID:20713400

Gilbert, C. L.; Morgan, C. W.

2010-01-01

103

Lunar Magmatic Volatiles  

Microsoft Academic Search

Samples returned from the Apollo Missions prompted a variety of experimental investigations (e.g., [1-4]) which form the basis of our current understanding of lunar compositional evolution. The observed low abundances of solidus temperature-suppressing volatiles justified volatile-free experiments. However, the low-pressure nature of the samples makes it unlikely that volatiles were retained during magma ascent and eruption. In an effort to

H. Nekvasil; F. M. McCubbin; D. H. Lindsley

2009-01-01

104

Food price volatility.  

PubMed

The high food prices experienced over recent years have led to the widespread view that food price volatility has increased. However, volatility has generally been lower over the two most recent decades than previously. Variability over the most recent period has been high but, with the important exception of rice, not out of line with historical experience. There is weak evidence that grains price volatility more generally may be increasing but it is too early to say. PMID:20713400

Gilbert, C L; Morgan, C W

2010-09-27

105

The expanded tomato fruit volatile landscape.  

PubMed

The present review aims to synthesize our present knowledge about the mechanisms implied in the biosynthesis of volatile compounds in the ripe tomato fruit, which have a key role in tomato flavour. The difficulties in identifiying not only genes or genomic regions but also individual target compounds for plant breeding are addressed. Ample variability in the levels of almost any volatile compound exists, not only in the populations derived from interspecific crosses but also in heirloom varieties and even in commercial hybrids. Quantitative trait loci (QTLs) for all tomato aroma volatiles have been identified in collections derived from both intraspecific and interspecific crosses with different wild tomato species and they (i) fail to co-localize with structural genes in the volatile biosynthetic pathways and (ii) reveal very little coincidence in the genomic regions characterized, indicating that there is ample opportunity to reinforce the levels of the volatiles of interest. Some of the identified genes may be useful as markers or as biotechnological tools to enhance tomato aroma. Current knowledge about the major volatile biosynthetic pathways in the fruit is summarized. Finally, and based on recent reports, it is stressed that conjugation to other metabolites such as sugars seems to play a key role in the modulation of volatile release, at least in some metabolic pathways. PMID:24692651

Rambla, José L; Tikunov, Yury M; Monforte, Antonio J; Bovy, Arnaud G; Granell, Antonio

2014-08-01

106

Integrated Chemical and Microorganism Monitoring of Air Using Gas Chromatography/Ion Mobility Spectometry: Toward an Expanded-Use Volatile Organic Analyzer (VOA)  

NASA Technical Reports Server (NTRS)

The work described in this research program originated with the choice by NASA of an ion mobility spectrometer for air quality monitoring on-board the international spacestation. Though the gas chromatograph-ion mobility spectrometer analyzer known as VOA met or exceeded expectations, limitations in the basic understanding of response and the utilization of foundational principles into usable technology was considered unacceptable. In this research program, a comprehensive model for the origins of mobility spectra was proposed, tested and verified. The principles considered responsible for the appearance of mobility spectra have now been elucidated through this project. This understanding has been applied in automated identification of mobility spectra using neural networks and routine procedures for this now exist. Finally, the limitation on linear range has been shown to be a technical limitation and not a fundamental limitation so that a hardware component was crafted to extend the linear range of a mobility spectrometer by 10X. This project has led to one Ph.D. dissertation and one MS thesis. In addition, over ten public presentations at professional meetings and six journal publications have resulted from this program of research. The findings are so plentiful that total analysis of the findings may require four to six years or more. The findings confirm that the decision to use VOA was sound and that the chemical and physical principles of mobility spectrometry are both understandable and predictable.

Eiceman, G. A.

1999-01-01

107

Project EARTH-12-MH2: The volatile history of past explosive eruptions  

E-print Network

a record of nearly all the major volatiles. This project will use the volatile contents of zoned apatites from relatively small eruptions to the highly explosive Campanian Ignimbrite. The student will sample

Henderson, Gideon

108

A BENCH SCALE STUDY ON BIODEGRADATION AND VOLATILIZATION OF ETHYLBENZOATE IN AQUIFERS. (R825549C039)  

EPA Science Inventory

Experiments were conducted to investigate the fate of ethylbenzoate and soil microorganisms in shallow aquifers. Biodegradation and volatilization have been identified as the major mechanisms in attenuating ethylbenzoate in contaminated soils. The rate of volatilization was ex...

109

Kinetics of the reactions of acetone and glyoxal with O2+ and NO+ ions and application to the detection of oxygenated volatile organic compounds in the atmosphere by chemical ionization mass spectrometry  

NASA Astrophysics Data System (ADS)

In situ measurements of oxygenated volatile organic compounds (OVOC) in the upper troposphere-lower stratosphere (UTLS) have gained strong interest because these compounds may be transported during convective events to the UTLS, where they may contribute to the HOx budget thus influencing the chemistry of ozone. With the aim to quantify OVOC of similar mass (58 u) by chemical ionization mass spectrometry (CIMS), ion-molecule reactions of acetone and glyoxal with O2+ and NO+ have been studied. O2+ reacts at the theoretical collision rate with acetone and glyoxal, with room-temperature rate constant values of (3.1 ± 0.7) × 10-9 and (1.8 ± 0.4) × 10-9 cm3 molecule-1 s-1, respectively, independent of pressure. The charge transfer product ion (m/z 58) and a specific fragment product ion are formed for each reaction. NO+ reacts with acetone and glyoxal with a rate constant lower than the collision rate in N2 buffer gas at 1.7 hPa, leading to the formation of the association product in both cases as single reaction productE The rate constants increase with pressure at 295 K for both ranges of 1.2-19.2 hPa N2 and 1.3-2.6 hPa He, indicating a falloff kinetic regime. These results are analysed using conventional statistical calculations. Consistency of the rate constants is obtained for both buffer gases and pressure ranges employed, and high-pressure limits are in agreement with the collision rate constants. Troe analytical expressions of the rate constants are derived for use under any pressure and temperature. From the reaction kinetics and mechanisms obtained in this study and others, a scheme is discussed to quantify separately acetone, glyoxal, and propanal in the UTLS by CIMS, using NO+, O2+, and H3O+ as reagent ions, taking into account potential interferences from other important OVOC such as acetaldehyde and from non-methane hydrocarbons such as n-propane, butane and 2-methyl propane.

Guimbaud, C.; Catoire, V.; Bergeat, A.; Michel, E.; Schoon, N.; Amelynck, C.; Labonnette, D.; Poulet, G.

2007-06-01

110

Volatile Analyzer for Lunar Polar Missions  

NASA Technical Reports Server (NTRS)

One of the major questions remaining for the future exploration of the Moon by humans concerns the presence of volatiles on our nearest neighbor in space. Observational studies, and investigations involving returned lunar samples and using robotic spacecraft infer the existence of volatile compounds particularly water [1]. It seems very likely that a volatile component will be concentrated at the poles in circumstances where low-temperatures exist to provide cryogenic traps. However, the full inventory of species, their concentration and their origin and sources are unknown. Of particular importance is whether abundances are sufficient to act as a resource of consumables for future lunar expeditions especially if a long-term base involving humans is to be established. To address some of these issues requires a lander designed specifically for operation at a high-lunar latitude. A vital part of the payload needs to be a volatile analyzer such as the Gas Analysis Package specifically designed for identification quantification of volatile substances and collecting information which will allow the origin of these volatiles to be identified [1]. The equipment included, particularly the gas analyzer, must be capable of operation in the extreme environmental conditions to be encountered. No accurate information yet exists regarding volatile concentration even for sites closer to the lunar equator (because of contamination). In this respect it will be important to understand (and thus limit) contamination of the lunar surface by extraneous material contributed from a variety of sources. The only data for the concentrations of volatiles at the poles comes from orbiting spacecraft and whilst the levels at high latitudes may be greater than at the equator, the volatile analyzer package under consideration will be designed to operate at the highest specifications possible and in a way that does not compromise the data.

Gibons, Everett K.; Pillinger, Colin T.; McKay, David S.; Waugh, Lester J.

2011-01-01

111

Detection and validation of volatile metabolic patterns over different strains of two human pathogenic bacteria during their growth in a complex medium using multi-capillary column-ion mobility spectrometry (MCC-IMS).  

PubMed

Headspace analyses over microbial cultures using multi-capillary column-ion mobility spectrometry (MCC-IMS) could lead to a faster, safe and cost-effective method for the identification of pathogens. Recent studies have shown that MCC-IMS allows identification of bacteria and fungi, but no information is available from when on during their growth a differentiation between bacteria is possible. Therefore, we analysed the headspace over human pathogenic reference strains of Escherichia coli and Pseudomonas aeruginosa at four time points during their growth in a complex fluid medium. In order to validate our findings and to answer the question if the results of one bacterial strain can be transferred to other strains of the same species, we also analysed the headspace over cultures from isolates of random clinical origin. We detected 19 different volatile organic compounds (VOCs) that appeared or changed their signal intensity during bacterial growth. These included six VOCs exclusively changing over E. coli cultures and seven exclusively changing over P. aeruginosa cultures. Most changes occurred in the late logarithmic or static growth phases. We did not find differences in timing or trends in signal intensity between VOC patterns of different strains of one species. Our results show that differentiation of human pathogenic bacteria by headspace analyses using MCC-IMS technology is best possible during the late phases of bacterial growth. Our findings also show that VOC patterns of a bacterial strain can be transferred to other strains of the same species. PMID:23467822

Kunze, Nils; Göpel, Julia; Kuhns, Martin; Jünger, Melanie; Quintel, Michael; Perl, Thorsten

2013-04-01

112

Emerging equity market volatility  

Microsoft Academic Search

Understanding volatility in emerging capital markets is important for determining the cost of capital and for evaluating direct investment and asset allocation decisions. We provide an approach that allows the relative importance of world and local information to change through time in both the expected returns and conditional variance processes. Our time-series and cross-sectional models analyze the reasons that volatility

Geert Bekaert; Campbell R. Harvey

1997-01-01

113

Bond Illiquidity and Excess Volatility  

E-print Network

We find that the empirical volatilities of corporate bond and CDS returns are higher than implied by equity return volatilities and the Merton model. This excess volatility may arise because structural models inadequately ...

Bao, Jack

114

Volatility modeling in financial markets  

E-print Network

Volatility modeling in financial markets Master Thesis Sergiy Ladokhin of volatility modeling in financial markets. It begins with a general description of volatility and its properties, and discusses its usage in financial risk management. The research is divided into two

Bhulai, Sandjai

115

Nanosims Imaging of Volatile Elements (H, C, F and S) in Shergottites  

NASA Technical Reports Server (NTRS)

Volatiles, especially water, play a critical role in the evolution of Mars and other planetary bodies. Though the detection limit and spatial resolution in measuring volatiles in different phases of Martian meteorites have been greatly improved using ion microprobes (SIMS), it remains a challenge to accurately determine volatile concentrations due to contamination by terrestrial volatiles. Most Martian meteorites experienced cracking and shattering from the high-pressure shock either on the Martian surface and/or when coming to Earth. Martian meteorites generally contain volatiles in cracks even after careful sample preparation for SIMS analysis. We used the Cameca NanoSIMS 50L at Carnegie Institution of Washington to image volatile (H, C, F and S) distributions in two shergottite meteorites, LAR 06319 (L2) and Y-980456 (Y3). The mapping of volatiles in these meteorites greatly assisted us in understanding the distribution of volatile contamination and in improving future volatile measurement methods

Wang, J.; Usui, T.; Alexander, C. M. O'D.; Simon, J. I.; Jones, J. H.

2012-01-01

116

Ecological functions of volatile organic compounds in aquatic systems  

Microsoft Academic Search

In terrestrial ecosystems, volatile organic compounds (VOCs) are widely acknowledged as an important group of infochemicals. They play a major role in pollinator attraction by terrestrial plants and as insect pheromones. Furthermore, they are the mediating agent of so-called ‘tritrophic interactions’. When plants are attacked by herbivorous insects, volatile signal substances are emitted, which act as attractants for parasitoids that

Patrick Fink

2007-01-01

117

The maize lipoxygenase, ZmLOX10, mediates green leaf volatile, jasmonate and herbivore-induced plant volatile  

E-print Network

-induced plant volatile production for defense against insect attack Shawn A. Christensen1,§ , Andriy Nemchenko1 insect herbivores; however, major regulatory genes and the signals that modulate these defense in herbivore-induced plant volatiles (HIPVs) and attractiveness to parasitoid wasps. Because LOX10 is under

Jackson, David

118

Sodium Channels as Targets for Volatile Anesthetics  

PubMed Central

The molecular mechanisms of modern inhaled anesthetics are still poorly understood although they are widely used in clinical settings. Considerable evidence supports effects on membrane proteins including ligand- and voltage-gated ion channels of excitable cells. Na+ channels are crucial to action potential initiation and propagation, and represent potential targets for volatile anesthetic effects on central nervous system depression. Inhibition of presynaptic Na+ channels leads to reduced neurotransmitter release at the synapse and could therefore contribute to the mechanisms by which volatile anesthetics produce their characteristic end points: amnesia, unconsciousness, and immobility. Early studies on crayfish and squid giant axon showed inhibition of Na+ currents by volatile anesthetics at high concentrations. Subsequent studies using native neuronal preparations and heterologous expression systems with various mammalian Na+ channel isoforms implicated inhibition of presynaptic Na+ channels in anesthetic actions at clinical concentrations. Volatile anesthetics reduce peak Na+ current (INa) and shift the voltage of half-maximal steady-state inactivation (h?) toward more negative potentials, thus stabilizing the fast-inactivated state. Furthermore recovery from fast-inactivation is slowed, together with enhanced use-dependent block during pulse train protocols. These effects can depress presynaptic excitability, depolarization and Ca2+ entry, and ultimately reduce transmitter release. This reduction in transmitter release is more potent for glutamatergic compared to GABAergic terminals. Involvement of Na+ channel inhibition in mediating the immobility caused by volatile anesthetics has been demonstrated in animal studies, in which intrathecal infusion of the Na+ channel blocker tetrodotoxin increases volatile anesthetic potency, whereas infusion of the Na+ channels agonist veratridine reduces anesthetic potency. These studies indicate that inhibition of presynaptic Na+ channels by volatile anesthetics is involved in mediating some of their effects. PMID:22479247

Herold, Karl F.; Hemmings Jr., Hugh C.

2012-01-01

119

Volatile terpenoids from aeciospores of Cronartium fusiforme.  

NASA Technical Reports Server (NTRS)

Identification of the terpenoids present in the volatile fraction from aeciospores of the gall rust fungus Cronartium fusiforme. The major monoterpenoid hydrocarbons found to be present with only traces of camphene include alpha-pinene, beta-pinene, delta(3)-carene, myrcene, linonene, beta-phellandrene, and delta-terpinene. A number of monoterpenoid alcohols, acyclic sesquiterpenes, and aromatic compounds were also present.

Laseter, J. L.; Weete, J. D.; Walkinshaw, C. H.

1973-01-01

120

Volatile halocarbons in water  

SciTech Connect

Volatile halocarbons in drinking water have attracted increasing attention during recent years. These substances are also found in body fluids. All disinfectant chemicals used in water treatment seem to produce by-products. Of particular concern are the following substances from the use of various disinfectants according to US EPA: chlorine, bromine and iodine, and chlorine dioxide. The aim of the present study was to follow the formation and occurrence of volatile halocarbons in different types of water.

Kroneld, R.

1986-11-01

121

Theoretical predictions of volatile bearing phases and volatile resources in some carbonaceous chondrites  

NASA Technical Reports Server (NTRS)

Carbonaceous chondrites are usually believed to be the primary constituents of near-Earth asteroids and Phobos and Diemos, and are potential resources of fuels which may be exploited for future planetary missions. The nature and abundances are calculated of the major volatile bearing and other phases, including the vapor phase that should form in C1 and C2 type carbonaceous chondrites as functions of pressure and temperature. The results suggest that talc, antigorite plus or minus magnesite are the major volatile bearing phases and are stable below 400 C at 1 bar in these chondritic compositions. Simulated heating of a kilogram of C2 chondrite at fixed bulk composition between 400 and 800 C at 1 bar yields about 135 gm of volatile, which is made primarily of H2O, H2, CH4, CO2 and CO. The relative abundances of these volatile species change as functions of temperature, and on a molar basis, H2 becomes the most dominant species above 500 C. In contrast, Cl chondrites yield about 306 gm of volatile under the same condition, which consist almost completely of 60 wt percent H2O and 40 wt percent CO2. Preliminary kinetic considerations suggest that equilibrium dehydration of hydrous phyllosilicates should be attainable within a few hours at 600 C. These results provide the framework for further analyses of the volatile and economic resource potentials of carbonaceous chondrites.

Ganguly, Jibamitra; Saxena, Surendra K.

1989-01-01

122

One-year observations of carbonaceous and nitrogenous components and major ions in the aerosols from subtropical Okinawa Island, an outflow region of Asian dusts  

NASA Astrophysics Data System (ADS)

Ambient aerosol samples (TSP, n = 50) were collected for 12 months at subtropical Okinawa Island, Japan, an outflow region of Asian dusts in the western North Pacific and analysed for organic carbon (OC), elemental carbon (EC), water-soluble organic carbon (WSOC), water-soluble total nitrogen (WSTN), water-soluble organic nitrogen (WSON) and major ions to better understand the formation and transformation of East Asian aerosols during long-range atmospheric transport. Concentration ranges of these components are; OC: 0.76-7.1 ?g m-3 (av. 1.7 ± 1.0 ?g m-3), EC: 0.07-0.96 ?g m-3 (0.28 ± 0.19 ?g m-3), WSOC: 0.27-1.9 ?g m-3 (0.73 ± 0.38 ?g m-3), WSTN: 0.77 to 3.0 ?g m-3 (0.58 ± 0.46 ?g m-3) and WSON: 0.0-2.2 ?g m-3 (0.12 ± 0.23 ?g m-3). Higher OC concentrations were obtained in active biota seasons; spring (av. 2.4 ?g m-3) and summer (1.8 ?g m-3). EC and WSOC concentrations maximized in spring (av. 0.41 ?g m-3 and 0.95 ?g m-3, respectively) followed by winter (0. 70 and 0.90 ?g m-3) whereas they became lowest in summer (0.19 and 0.52 ?g m-3). In contrast, WSTN concentrations were highest in winter (0.86 ?g m-3) and lowest in summer (0.37 ?g m-3) and autumn (0.34 ?g m-3). Concentrations of WSON are higher in early summer (av. 0.26 ?g m-3) due to the emission from marine biota. The high ratios of OC / EC (av. 7.6) and WSOC / OC (44%) suggest a secondary formation of organic aerosols. Strong correlation between OC and MSA- (0.81) in spring suggests that springtime aerosols are influenced by additional marine and terrestrial biogenic sources. The positive correlation of Ca2+ and TSP in spring (r = = 0.81) demonstrates a significant contribution of Asian dust whereas high abundances of NO3- and nss-SO42- in winter suggest an important contribution from anthropogenic sources including biomass burning, vehicular emission and coal combustion. NH4-N/WSTN ratios peaked in winter (0.56), indicating a significant contribution of biomass burning to WSTN in cold season. In contrast, higher NO3-N/WSTN ratio in spring than winter suggests that the atmospheric transport of vehicular emissions maximizes in spring. Correlation analyses of major ions suggest that NH4+ and Ca2+ play major role in the neutralization of acidic aerosols forming NH4HSO4, (NH4)2SO4 and CaSO4.

Kunwar, B.; Kawamura, K.

2014-02-01

123

Examining Stock Volatility in the Segmented Chinese Stock Markets: A SWARCH Approach  

Microsoft Academic Search

This study adopts the SWARCH model to examine the volatile behavior and volatility linkages among the four major segmented Chinese stock indices. We find strong evidence of a regime shift in the volatility of the four markets, and the SWARCH model appears to outperform standard generalized autoregressive conditional heteroskedasticity (GARCH) family models. The evidence suggests that, compared with the A-share

Zhuo Qiao; Weiwei Qiao; Wing-Keung Wong

2010-01-01

124

Evaluation of ?-radiation on green tea odor volatiles  

NASA Astrophysics Data System (ADS)

The aim of this study was to evaluate the gamma radiation effects on green tea odor volatiles in green tea at doses of 0, 5, 10, 15 and 20 kGy. The volatile organic compounds were extracted by hydrodistillation and analyzed by GC/MS. The green tea had a large influence on radiation effects, increasing the identified volatiles in relation to control samples. The dose of 10 kGy was responsible to form the majority of new odor compounds following by 5 and 20 kGy. However, the dose of 5 kGy was the dose that degraded the majority of volatiles in non-irradiated samples, following by 20 kGy. The dose of 15 kGy showed has no effect on odor volatiles. The gamma radiation, at dose up to 20 kGy, showed statistically no difference between irradiated and non irradiated green tea on odors compounds.

Fanaro, G. B.; Duarte, R. C.; Araújo, M. M.; Purgatto, E.; Villavicencio, A. L. C. H.

2011-01-01

125

Lunar volatiles: balancing science and resource development  

NASA Astrophysics Data System (ADS)

In the context of human exploration of the moon, the volatiles postulated to exist at the lunar poles have value as resources as well as scientific significance. Once sustained human operations commence on the moon, society will move from a paradigm in which examination of planetary materials has been unconstrained to one where use of those materials will support habitability and further exploration. A framework for the scientific investigation of lunar volatiles that allows for eventual economic exploitation can guide both activities and resolve the conflicts that will inevitably develop if the postulated lunar volatiles prove to be both extant and accessible. Scientific constraints on the framework include characterization at both poles of the isotopes, elements, and molecules in the volatiles, their relative and absolute abundances, and their horizontal and vertical distribution. A subset of this data is necessary in order to assess, develop, and initiate resource exploitation. In addition, the scientific record of volatiles in the cold traps can be contaminated by the cold-trapping of migrating volatiles released from operations elsewhere on the moon even if the indigenous, cold-trapped volatiles are not utilized. Possible decision points defining the transition from science-dominated to exploitation-dominated use include technology limits in the 70K environment, evolving science priorities (funding), and the resolution of major science issues. Inputs to policy development include any North vs. South Pole differences in volatile characteristics and the suitability of the volatiles to enable further scientific exploration of the moon. In the absence of national sovereignty on the moon, enforcement of any framework is an open question, particularly if science and commercial interests are in competition. The framework, processes, and precedent set by how we as a society choose to handle the scientific bounty and resource promise of lunar volatiles may eventually apply to Mars and near-earth asteroids. We believe there are useful lessons to be learned from the terrestrial experience with protected areas such as national parks, wilderness areas, and archeological sites. International agreements such as the Antarctic Treaty (in force since 1961), the Outer Space Treaty (1967), and the Moon Treaty (1979) carry relevant lessons as well.

Crider, Dana

126

Apoptosis-mediated proliferation inhibition of human colon cancer cells by volatile principles of Citrus aurantifolia  

Microsoft Academic Search

Fruits of Citrus aurantifolia were subjected to hydro-distillation using Clevenger type apparatus to obtain volatile oil. Chemical composition of volatile oil was analysed by GC–MS. Twenty-two compounds representing more than 89.5% of the volatile oil were identified. d-limonene (30.13%) and d-dihydrocarvone (30.47%) were found to be the major compounds in the lime volatile oil. This oil showed 78% inhibition of

Jaiprakash R. Patil; G. K. Jayaprakasha; K. N. Chidambara Murthy; Shane E. Tichy; Mahadev B. Chetti; Bhimanagouda S. Patil

2009-01-01

127

Major ion chemistry in the headwaters of the Yamuna river system:. Chemical weathering, its temperature dependence and CO 2 consumption in the Himalaya  

NASA Astrophysics Data System (ADS)

The Yamuna river and its tributaries in the Himalaya constitute the Yamuna River System (YRS). The YRS basin has a drainage area and discharge comparable in magnitude to those of the Bhagirathi and the Alaknanda rivers, which merge to form the Ganga at the foothills of the Himalaya. A detailed geochemical study of the YRS was carried out to determine: (i) the relative significance of silicate, carbonate and evaporite weathering in contributing to its major ion composition; (ii) CO 2 consumption via silicate weathering; and (iii) the factors regulating chemical weathering of silicates in the basin. The results show that the YRS waters are mildly alkaline, with a wide range of TDS, ˜32 to ˜620 mg l-1. In these waters, the abundances of Ca, Mg and alkalinity, which account for most of TDS, are derived mainly from carbonates. Many of the tributaries in the lower reaches of the Yamuna basin are supersaturated with calcite. In addition to carbonic acid, sulphuric acid generated by oxidation of pyrites also seems to be supplying protons for chemical weathering. Silicate weathering in YRS basin contributes, on average, ˜25% (molar basis) of total cations on a basin wide scale. Silicate weathering, however, does not seem to be intense in the basin as evident from low Si/(Na*+K) in the waters, ˜1.2 and low values of chemical index of alteration (CIA) in bed sediments, ˜60. CO 2 drawdown resulting from silicate weathering in the YRS basin in the Himalaya during monsoon ranges between (4 to 7) × 10 5 moles km -2 y -1. This is higher than that estimated for the Ganga at Rishikesh for the same season. The CO 2 consumption rates in the Yamuna and the Ganga basins in the Himalaya are higher than the global average value, suggesting enhanced CO 2 drawdown in the southern slopes of the Himalaya. The impact of this enhanced drawdown on the global CO 2 budget may not be pronounced, as the drainage area of the YRS and the Ganga in the Himalaya is small. The CO 2 drawdown by silicates in the YRS basin is marginally higher than the reported values of CO 2 release from oxidation of organic rich sediments, estimated using Re as a proxy. This comparison shows the need to constrain CO 2 sources and sinks better to balance its budget in a regional scale. The results also show that silicate weathering rate in the YRS basin is ˜10 mm ky -1 and on the Ganga basin, it is ˜5 mm ky -1, which are several times lower than the carbonate weathering rates. The significantly higher silicate weathering rate observed in the YRS basin seems to be governed by rapid physical erosion in this region. The apparent activation energy for overall silicate weathering in the YRS basin, derived from Na* and Si concentrations and water temperature, ranges from ˜50 to 80 kJ mol -1. These values are comparable to those reported for granitoid weathering in natural watersheds and feldspar weathering in laboratory experiments. This study brings to light the sources contributing to major ions, enhanced chemical weathering rates in the Yamuna River Basin and interdependence of silicate weathering on physical erosion and temperature.

Dalai, T. K.; Krishnaswami, S.; Sarin, M. M.

2002-10-01

128

Volatiles of Chrysanthemum zawadskii var. latilobum K.  

PubMed

The volatile aroma constituents of Chrysanthemum zawadskii var. latilobum K. were separated by hydro distillation extraction (HDE) method using a Clevenger-type apparatus, and analyzed by gas chromatography-mass spectrometry (GC/MS). The yield of C. zawadskii var. latilobum K. flower essential oil (FEO) was 0.12% (w/w) and the color was light green. Fifty-five volatile chemical components, which make up 88.38% of the total aroma composition, were tentatively characterized. C. zawadskii var. latilobum K. FEOs contained 27 hydrocarbons, 12 alcohols, 7 ketones, 4 esters, 1 aldehyde, 1 amine, and 3 miscellaneous components. The major functional groups were terpene alcohol and ketone. Borneol (12.96), (±)-7-epi-amiteol (12.60), and camphor (10.54%) were the predominant volatiles. These compounds can be used in food and pharmaceutical industries due to their active bio-functional properties. PMID:24471090

Chang, Kyung-Mi; Kim, Gun-Hee

2012-09-01

129

Biogenic volatile emissions from the soil.  

PubMed

Volatile compounds are usually associated with an appearance/presence in the atmosphere. Recent advances, however, indicated that the soil is a huge reservoir and source of biogenic volatile organic compounds (bVOCs), which are formed from decomposing litter and dead organic material or are synthesized by underground living organism or organs and tissues of plants. This review summarizes the scarce available data on the exchange of VOCs between soil and atmosphere and the features of the soil and particle structure allowing diffusion of volatiles in the soil, which is the prerequisite for biological VOC-based interactions. In fact, soil may function either as a sink or as a source of bVOCs. Soil VOC emissions to the atmosphere are often 1-2 (0-3) orders of magnitude lower than those from aboveground vegetation. Microorganisms and the plant root system are the major sources for bVOCs. The current methodology to detect belowground volatiles is described as well as the metabolic capabilities resulting in the wealth of microbial and root VOC emissions. Furthermore, VOC profiles are discussed as non-destructive fingerprints for the detection of organisms. In the last chapter, belowground volatile-based bi- and multi-trophic interactions between microorganisms, plants and invertebrates in the soil are discussed. PMID:24689847

Peñuelas, J; Asensio, D; Tholl, D; Wenke, K; Rosenkranz, M; Piechulla, B; Schnitzler, J P

2014-08-01

130

Volatiles in protoplanetary disks  

E-print Network

Volatiles are compounds with low sublimation temperatures, and they make up most of the condensible mass in typical planet-forming environments. They consist of relatively small, often hydrogenated, molecules based on the abundant elements carbon, nitrogen and oxygen. Volatiles are central to the process of planet formation, forming the backbone of a rich chemistry that sets the initial conditions for the formation of planetary atmospheres, and act as a solid mass reservoir catalyzing the formation of planets and planetesimals. This growth has been driven by rapid advances in observations and models of protoplanetary disks, and by a deepening understanding of the cosmochemistry of the solar system. Indeed, it is only in the past few years that representative samples of molecules have been discovered in great abundance throughout protoplanetary disks - enough to begin building a complete budget for the most abundant elements after hydrogen and helium. The spatial distributions of key volatiles are being mapped...

Pontoppidan, Klaus M; Bergin, Edwin A; Brittain, Sean; Marty, Bernard; Mousis, Olvier; Oberg, Karin L

2014-01-01

131

Volatile constituents of wild and in vitro cultivated Gloeophyllum odoratum.  

PubMed

The brown-rot fungus Gloeophyllum odoratum was collected from spruce stumps in southern Finland. The volatiles in the fruiting body and fungal cultures grown in malt extract and liquid medium were investigated. Chitin, chitosan and D-(+)-glucosamine at a concentration of 450 mgl-1 medium were used as elicitors. Chitosan completely inhibited growth in the solid medium. The main volatile(s) according to GC and GC-MS analysis were either linalool, citronellol, geraniol and methyl p-methoxyphenylacetate or drimenol depending on the culture type and elicitor. The composition of volatiles in the natural fungus differed slightly from that of the cultivated fungus since the major compound was methyl p-methoxyphenylacetate. The volatile oils were toxic to larvae of the brine shrimp, Artemia salina, indicating that they may possess insecticidal and cytotoxic activity. PMID:7765210

Kahlos, K; Kiviranta, J L; Hiltunen, R V

1994-07-01

132

Lunar Magmatic Volatiles  

NASA Astrophysics Data System (ADS)

Samples returned from the Apollo Missions prompted a variety of experimental investigations (e.g., [1-4]) which form the basis of our current understanding of lunar compositional evolution. The observed low abundances of solidus temperature-suppressing volatiles justified volatile-free experiments. However, the low-pressure nature of the samples makes it unlikely that volatiles were retained during magma ascent and eruption. In an effort to re-assess the lunar mantle volatile budget, we are focusing on the mineral apatite because of its incorporation of F, Cl, and OH as essential structural constituents and its greater ability to retain such volatiles relative to melt. Apatite grains analyzed from magnesian- and alkali-suite rocks (14161,7111, 14161,7269 and 14161,7264), KREEPy impact melt rocks associated with magnesian- and alkali-suite rocks (14161,7233; 14161,7110; 14161,7062; 12033,634-25; SaU 169-4), and mare basalts (79195; 12037,224; 74246; 12023,147,1; 10084; LAP 02205; LAP 03632; NWA 2977) by electron microprobe using the technique of [5,6] show two distinct compositional groups. Apatite from the mare basalts analyzed are primarily mixtures of fluor- "missing component" (OH?) apatite with low Cl abundance, while that from the magnesian- and alkali-suite rocks are fluor-chlor mixtures. Apatite/basaltic melt partition coefficients for F, Cl, and H2O from the data of [7] provide first estimates of magmatic volatile abundances in lunar magmas. They suggest that magmatic water may have been more abundant than F and Cl at the stage of apatite crystallization in mare basalts. In contrast, at this stage, the magmas that produced the Mg-and alkali suite minerals were F- and Cl-dominated. These results have wide-reaching implications regarding the chemical and physical evolution of the Moon and therefore, the next generation of experimental investigations. [1] Walker et al. 1973 EPSL 20, 325-336. [2] Walker et al. 1975 GCA 39, 1219-1235. [3] Longhi 1992 GCA 69, 1275-1286. [4] Longhi 2003 JGR 108, E8, doi:10.1029/2002JE001941. [5] Stormer et al. 1993 Am Min 78, 641. [6] McCubbin et al. 20081st NLSI Conference. [7] Mathez and Webster 2005 GCA 69, 1275-1286.

Nekvasil, H.; McCubbin, F. M.; Lindsley, D. H.

2009-05-01

133

Headspace sampling and detection of cocaine, MDMA, and marijuana via volatile markers in the presence of potential interferences by solid phase microextraction-ion mobility spectrometry (SPME-IMS).  

PubMed

The successful air sampling and detection of cocaine, methylenedioxymethylamphetamine (MDMA), and marijuana using SPME-IMS achieved by targeting their volatile markers (methyl benzoate, piperonal, and terpenes, respectively) is presented. Conventional methods of direct air sampling for drugs are ineffective because the parent compounds of these drugs have very low vapor pressures, making them unavailable for headspace sampling. Instead of targeting the parent drugs, IMS was set at the optimal operating conditions (determined in previous work) in order to detect their volatile chemical markers. SPME is an effective and rapid air sampling technique for the preconcentration of analytes which is especially useful in confined spaces such as cargo containers, where the volatile marker compounds of drugs can be found in sufficient concentrations. By sampling the air using a 100 microm polydimethyl siloxane (PDMS) SPME fiber for as little as one minute, enough mass of the targeted volatile markers in the headspace of a quart-sized metal paint can (gallon, approximately 1101 cm(3)) which contained sub-gram quantities of the drug samples was recovered for IMS detection. Additionally, several potentially interfering compounds found in goods commonly shipped in cargo containers were tested individually as well as in mixtures with the drugs. No peak interferences were observed for MDMA or marijuana, and minimal peak interferences were found for cocaine. PMID:18600317

Lai, Hanh; Corbin, Inge; Almirall, José R

2008-09-01

134

Analysis of volatile organic compounds from illicit cocaine samples  

SciTech Connect

Detection of illicit cocaine hydrochloride shipments can be improved if there is a greater understanding of the identity and quantity of volatile compounds present. This study provides preliminary data concerning the volatile organic compounds detected in a limited Set of cocaine hydrochloride samples. In all cases, cocaine was one of the major volatile compounds detected. Other tropeines were detected in almost all samples. Low concentrations of compounds that may be residues of processing solvents were observed in some samples. The equilibrium emissivity of. cocaine from cocaine hydrochloride was investigated and a value of 83 parts-per-trillion was determined.

Robins, W.H.; Wright, B.W.

1994-07-01

135

Major depression  

MedlinePLUS

... major; Depression - clinical; Clinical depression; Unipolar depression; Major depressive disorder ... Doctors do not know the exact causes of depression. It is believed ... responsible. This may be due to a problem with your genes. Or ...

136

Mechanism of Formation of the Major Estradiol Product Ions Following Collisional Activation of the Molecular Anion in a Tandem Quadrupole Mass Spectrometer  

NASA Astrophysics Data System (ADS)

The importance of the mass spectral product ion structure is highlighted in quantitative assays, which typically use multiple reaction monitoring (MRM), and in the discovery of novel metabolites. Estradiol is an important sex steroid whose quantitation and metabolite identification using tandem mass spectrometry has been widely employed in numerous clinical studies. Negative electrospray ionization tandem mass spectrometry of estradiol (E2) results in several product ions, including the abundant m/z 183 and 169. Although m/z 183 is one of the most abundant product ions used in many quantitative assays, the structure of m/z 183 has not been rigorously examined. We suggest a structure for m/z 183 and a mechanism of formation consistent with collision induced dissociation (CID) of E2 and several stable isotopes ([D4]-E2, [13C6]-E2, and [D1]-E2). An additional product ion from E2, namely m/z 169, has also been examined. MS3 experiments indicated that both m/z 183 and m/z 169 originate from only E2 [M - H]- m/z 271. These ions, m/z 183 and m/z 169, were also present in the collision induced decomposition mass spectra of other prominent estrogens, estrone (E1) and estriol (E3), indicating that these two product ions could be used to elucidate the estrogenic origin of novel metabolites. We propose two fragmentation schemes to explain the CID data and suggest a structure of m/z 183 and m/z 169 consistent with several isotopic variants and high resolution mass spectrometric measurements.

Wooding, Kerry M.; Barkley, Robert M.; Hankin, Joseph A.; Johnson, Christopher A.; Bradford, Andrew P.; Santoro, Nanette; Murphy, Robert C.

2013-10-01

137

Herbivore induced plant volatiles  

PubMed Central

Plants respond to herbivory through different defensive mechanisms. The induction of volatile emission is one of the important and immediate response of plants to herbivory. Herbivore-induced plant volatiles (HIPVs) are involved in plant communication with natural enemies of the insect herbivores, neighboring plants, and different parts of the damaged plant. Release of a wide variety of HIPVs in response to herbivore damage and their role in plant-plant, plant-carnivore and intraplant communications represents a new facet of the complex interactions among different trophic levels. HIPVs are released from leaves, flowers, and fruits into the atmosphere or into the soil from roots in response to herbivore attack. Moreover, HIPVs act as feeding and/or oviposition deterrents to insect pests. HIPVs also mediate the interactions between the plants and the microorganisms. This review presents an overview of HIPVs emitted by plants, their role in plant defense against herbivores and their implications for pest management. PMID:22105032

War, Abdul Rashid; Sharma, Hari Chand; Paulraj, Michael Gabriel; War, Mohd Yousf; Ignacimuthu, Savarimuthu

2011-01-01

138

How Markets Process Information: News Releases and Volatility  

Microsoft Academic Search

The authors examine the impact of scheduled macroeconomic news announcements on interest rate and foreign exchange futures markets. They find these announcements are responsible for most of the observed time-of-day and day-of-the-week volatility patterns in these markets. While the bulk of the price adjustment to a major announcement occurs within the first minute, volatility remains substantially higher than normal for

Louis H Ederington; Jae Ha Lee

1993-01-01

139

Atmospheric pressure chemical ionisation mass spectrometry for in vivo analysis of volatile flavour release  

Microsoft Academic Search

To follow volatile flavour release in the expired air of people during eating, several physiological and analytical constraints must be observed to obtain good quality data. An interface has been developed to sample air from the nose and ionise the volatile compounds contained therein by atmospheric pressure chemical ionisation. The ions formed are detected in a quadrupole mass spectrometer. The

A. J. Taylor; R. S. T. Linforth; B. A. Harvey; A. Blake

2000-01-01

140

Quorum-sensing quenching by rhizobacterial volatiles.  

PubMed

We show that volatile organic compounds (VOCs) produced by rhizospheric strains Pseudomonas fluorescens B-4117 and Serratia plymuthica IC1270 may act as inhibitors of the cell-cell communication quorum-sensing (QS) network mediated by N-acyl homoserine lactone (AHL) signal molecules produced by various bacteria, including strains of Agrobacterium, Chromobacterium, Pectobacterium and Pseudomonas. This quorum-quenching effect was observed when AHL-producing bacteria were treated with VOCs emitted by strains B-4117 and IC1270 or with dimethyl disulfide (DMDS), the major volatile produced by strain IC1270. LC-MS/MS analysis revealed that treatment of strains Pseudomonas chlororaphis 449, Pseudomonas aeruginosa PAO1 or Ps.?fluorescens 2-79 with VOCs emitted by strain IC1270 or DMDS drastically decreases the amount of AHLs produced by these bacteria. Volatile organic compounds produced by Ps.?chlororaphis 449 were able to suppress its own QS-induction activity, suggesting a negative interaction between VOCs and AHL molecules in the same strain. Quantitative RT-PCR analysis showed that treatment of Ps.?chlororaphis 449 with VOCs emitted by cells of IC1270, B-4117 or 449 itself, or with DMDS, leads to significant suppression of transcription of AHL synthase genes phzI and csaI. Thus, along with AHLs, bacterial volatiles might be considered another type of signal molecule involved in microbial communication in the rhizosphere. PMID:23761359

Chernin, Leonid; Toklikishvili, Natela; Ovadis, Marianna; Kim, Sofia; Ben-Ari, Julius; Khmel, Inessa; Vainstein, Alexander

2011-12-01

141

Compilation of toxicological data of major volatile essential oil components.  

E-print Network

??Seit Jahrhunderten werden ätherische Öle in der Volksmedizin weltweit verwendet um diverse Krankheiten zu therapieren. Auch in den Parfum-, Kosmetik- und Nahrungsmittelindustrien sind viele ätherische… (more)

El-Fadel, Tania

2013-01-01

142

Time-varying volatility in Malaysian stock exchange: An empirical study using multiple-volatility-shift fractionally integrated model  

NASA Astrophysics Data System (ADS)

This article investigated the influences of structural breaks on the fractionally integrated time-varying volatility model in the Malaysian stock markets which included the Kuala Lumpur composite index and four major sectoral indices. A fractionally integrated time-varying volatility model combined with sudden changes is developed to study the possibility of structural change in the empirical data sets. Our empirical results showed substantial reduction in fractional differencing parameters after the inclusion of structural change during the Asian financial and currency crises. Moreover, the fractionally integrated model with sudden change in volatility performed better in the estimation and specification evaluations.

Cheong, Chin Wen

2008-02-01

143

The glutamate-receptor ion channels (iGluRs), namely AMPA, kainate and NMDA receptors, are the major mediators of excitatory synaptic  

E-print Network

The glutamate-receptor ion channels (iGluRs), namely AMPA, kainate and NMDA receptors. These monitor changes in membrane potential and the presence of glutamate in the synaptic cleft4 . AMPA analysis of native glutamate receptors a formidable task. Biophysical studies have revealed many intriguing

Alford, Simon

144

ANALYSIS OF VOLATILES AND SEMIVOLATILES BY DIRECT AQUEOUS INJECTION  

EPA Science Inventory

Direct aqueous injection analysis (DAI) with gas chromatographic separation and ion trap mass spectral detection was used to analyze aqueous samples for g/L levels of 54 volatile and semivolatile compounds, and problematic non-purgeables and non-extractables. The method reduces ...

145

Major Ion Geochemistry of Horseshoe Lake, Mammoth Lakes, California: Water Quality in a Region with Elevated CO2 from Sub-Surface Leakage  

NASA Astrophysics Data System (ADS)

Tree-kill areas around Horseshoe Lake indicate how naturally high levels of carbon dioxide (CO2) emitted from a cooling magma chamber are affecting the ecosystem. CO2 leakage from geologically sequestered CO2 sites may have similar effects. Weathering processes and water quality changes are two other environmental impacts of high levels of CO2 leaking from subsurface CO2 reservoirs. This study’s focus was to conduct a geochemical study of Horseshoe Lake with emphasis on water chemistry to determine any quantifiable effects from the high release of volcanic CO2. We collected 22 water samples, including 5 samples from streams that drained into the lake. Two interior locations were sampled at the surface and at depths of 2-meter intervals. The interior lake samples showed increasing Mg and Ca concentrations from the surface to 12 m in depth, and increasing Sr and Si from the surface to 4 m in depth. Water samples were measured for temperature, conductivity, pH, alkalinity, and analyzed for major ions Ca2+, K+, Na+, Mg2+, Cl-, SO42-, and HCO3- (from alkalinity). Amounts of Al, Ca, K, Mg, Na, and high levels of Si from elemental data are consistent with waters in granitic environments. Temperature in the lakes and streams ranged from 3.5 to 16 °C, pH ranged from 5.9-7.2, conductivity ranged from 8.66 to 21.93 ?S/cm, and alkalinity ranged from 0.137- 0.408 meq/L. A TSI Q-Trak™ measured soil and ambient CO2 concentrations in July and a Vernier LabQuest was used in August. A bottomless bottle was placed in the soil in a10cm deep hole with the probe inserted in the top. A probe about 1 m above ground measured the ambient CO2 concentrations. To determine the flux of soil CO2, concentrations were read over a 5-minute time period. CO2 gas concentrations in the tree kill area ranged from 600 to 1,700 ppm in ambient air, and over 99,000 ppm in the soil. Maximum readings were exceeded so actual values of CO2 in the soil are not known. The stream samples had a different solute composition than the lake. Stream samples tended to have higher Al and Si concentrations than the lake. For Al 9.3 x 10-7 to 1.8 x 10-6 moles/L in the streams and 4.8 x 10-7 to 1.2 x 10-6 moles/L in the lake, and for Si 1.3 x 10-4 to 2.1 x 10 -4 moles/L in the streams, 1.1 x 10-4 to 1.2 x 10-4 moles/L in the lake. Stream samples had and lower concentrations of Mg and Ca than lake perimeter and interior surface samples. Values for Mg were 6.0 x 10-6 to 1.1 x 10-5 moles/L in the streams and about 1.1 x 10-5 in the lake, and for Ca 9.3 x 10-7 to 1.8 x 10-6 moles/L in the stream, 4.3 x 10-5 to 4.5 x 10-5 in the lake. The difference could be because of weathering processes or because of unknown other inputs such as springs or groundwater. Additionally, Horseshoe Lake may be stratified, with different solutes dominating at different depths. Evaporation from the lake could also cause more concentrated solutes in solution. The data was generally consistent with results from previous USGS, but our samples were more dilute showing the impact of high precipitation during 2009 and 2010.

Santilena, R.; Szutu, D.; Ellis, A. S.; Khachikian, C. S.

2010-12-01

146

Plants suppress their emission of volatiles when growing with conspecifics.  

PubMed

Plant volatiles mediate interactions with herbivores, herbivore enemies, and abiotic stresses, but these interactions mostly have been studied with individual isolated plants. It is not yet known how intra- and interspecific plant competition influence volatile emission. In a greenhouse experiment, we investigated the volatile emission by red clover (Trifolium pratense) growing alone, with a conspecific, or with an individual of the naturally co-occurring orchard grass, Dactylis glomerata. The individual and combined effects of above- and below ground plant contact were investigated. When T. pratense grew together with a conspecific, both total and herbivore-induced emission of volatiles was significantly reduced as compared to T. pratense growing with D. glomerata or growing alone. This reduction in emission occurred despite the fact that there was a significant reduction in T. pratense biomass due to competition with D. glomerata. The suppression of T. pratense volatile emission growing next to a conspecific was a general pattern observed for all major herbivore-induced volatiles and independent of whether plants were in contact above ground, below ground, or both above- and below ground. The reduction in volatile emission from plants growing with conspecifics may serve to reduce attack by specialist herbivores and minimize exploitation of herbivore attack information by neighbors. PMID:23525954

Kigathi, Rose N; Weisser, Wolfgang W; Veit, Daniel; Gershenzon, Jonathan; Unsicker, Sybille B

2013-04-01

147

Determination of volatile compounds in cider spirits by gas chromatography with direct injection.  

PubMed

Two analytical methods based on gas chromatography with direct injection are described for the quantitative analysis of volatile compounds (acetals, aldehydes, esters, alcohols, and volatile phenols) in cider brandies. Analytes were divided into major, 15, and minor volatile, 24, compounds depending on their usual concentration in samples. Parameters usually tested for method validation are evaluated. Correlation coefficients are calculated to estimate linearity, obtaining values higher than 0.999. Detection limits range between 0.325 mg/L (1-propanol) and 1.663 mg/L (methanol) among the major volatile compounds and between 0.086 mg/L (ethyl 2-methylbutyrate) and 0.332 mg/L (ethyl tetradecanoate) among the minor volatiles. Mean recoveries ranged between 109% (ethyl lactate) and 95% (1-butanol) for major volatiles and between 109% (1-octen-3-ol) and 94% (ethyl 2-methylbutyrate) for minor volatiles, thus confirming the accuracy of both methods. Reproducibility for major volatiles is < 5.4% (furfural) in all cases and < 9.6% (hexyl acetate) for minor volatiles. Moreover, the accuracy of the methods is evaluated by analyzing a certified whisky and five samples from interlaboratory assays, generally obtaining results in accordance with previous values. PMID:17725870

Rodríguez Madrera, Roberto; Suárez Valles, Belén

2007-08-01

148

Metal price volatility : a study of informative metrics and the volatility mitigating effects of recycling  

E-print Network

Metal price volatility is undesirable for firms that use metals as raw materials, because price volatility can translate into volatility of material costs. Volatile material costs and can erode the profitability of the ...

Fleming, Nathan Richard

2011-01-01

149

Major Programs  

Cancer.gov

The Division of Cancer Prevention supports major scientific collaborations and research networks at more than100 sites across the United States; investigator-initiated grants; postdoctoral training; and specialized resources for researchers.

150

Volatile constituents of dog ( Canis familiaris ) and coyote ( Canis latrans ) anal sacs  

Microsoft Academic Search

The volatile organic compounds from the anal sac secretions of male and female dogs and coyotes were examined using gas chromatography and gas chromatography-mass spectrometry. Short chain (C2–C6) acids and trimethylamine were major constituents. Changes in the type and abundance of the volatiles were examined across state of estrus, species, and gender. No consistent difference in the pattern of volatiles

George Preti; Earl L. Muetterties; Joseph M. Furman; James J. Kennelly; Bradford E. Johns

1976-01-01

151

Volatilizing toxic metals from soil  

Microsoft Academic Search

This study revealed that lead, cadmium, mercury, zinc, arsenic, and selenium can be volatilized from both spiked and actual contaminated soils by heating in inert or reducing atmospheres. Generally oxygen proved to be detrimental to the remediation process. An apparatus capable of rapidly heating soil samples to as high as 1,100 C was designed and built to volatilize toxic inorganic

D. A. Clifford; Shensin Chen; C. Reznik

1993-01-01

152

Expected stock returns and volatility  

Microsoft Academic Search

This paper examines the relation between stock returns and stock market volatility. We find evidence that the expected market risk premium (the expected return on a stock portfolio minus the Treasury bill yield) is positively related to the predictable volatility of stock returns. There is also evidence that unexpected stock market returns are negatively related to the unexpected change in

Kenneth R. French; G. William Schwert; Robert F. Stambaugh

1987-01-01

153

Volatile corrosion inhibitors: a review  

Microsoft Academic Search

Purpose – To provide a selective bibliography for graduate students and new faculty members with sources which can help them develop their academic career. Design\\/methodology\\/approach – A range of published (1951-2004) works, which aim to discuss the main parameters of the volatile corrosion inhibition process. The sources are sorted into sections: transport of the volatile corrosion inhibitor (VCI) to the

D. M. Bastidas; E. Cano; E. M. Mora

2005-01-01

154

Major depression.  

PubMed

Major depression is a common, disabling condition seen frequently in primary care practices. Non-psychiatrist ambulatory providers are increasingly responsible for diagnosing, and primarily managing patients suffering from major depressive disorder (MDD). The goal of this review is to help primary care providers to understand the natural history of MDD, identify practical tools for screening, and a thoughtful approach to management. Clinically challenging topics like co-morbid conditions, treatment resistant depression and pharmacotherapy selection with consideration to side effects and medication interactions, are also covered. PMID:25134869

Bentley, Susan M; Pagalilauan, Genevieve L; Simpson, Scott A

2014-09-01

155

Biofiltration of volatile organic compounds.  

PubMed

The removal of volatile organic compounds (VOCs) from contaminated airstreams has become a major air pollution concern. Improvement of the biofiltration process commonly used for the removal of odorous compounds has led to a better control of key parameters, enabling the application of biofiltration to be extended also to the removal of VOCs. Moreover, biofiltration, which is based on the ability of micro-organisms to degrade a large variety of compounds, proves to be economical and environmentally viable. In a biofilter, the waste gas is forced to rise through a layer of packed porous material. Thus, pollutants contained in the gaseous effluent are oxidised or converted into biomass by the action of microorganisms previously fixed on the packing material. The biofiltration process is then based on two principal phenomena: (1) transfer of contaminants from the air to the water phase or support medium, (2) bioconversion of pollutants to biomass, metabolic end-products, or carbon dioxide and water. The diversity of biofiltration mechanisms and their interaction with the microflora mean that the biofilter is defined as a complex and structured ecosystem. As a result, in addition to operating conditions, research into the microbial ecology of biofilters is required in order better to optimise the management of such biological treatment systems. PMID:15803311

Malhautier, Luc; Khammar, Nadia; Bayle, Sandrine; Fanlo, Jean-Louis

2005-07-01

156

Subduction and volatile recycling in Earth's mantle  

NASA Technical Reports Server (NTRS)

The subduction of water and other volatiles into the mantle from oceanic sediments and altered oceanic crust is the major source of volatile recycling in the mantle. Until now, the geotherms that have been used to estimate the amount of volatiles that are recycled at subduction zones have been produced using the hypothesis that the slab is rigid and undergoes no internal deformation. On the other hand, most fluid dynamical mantle flow calculations assume that the slab has no greater strength than the surrounding mantle. Both of these views are inconsistent with laboratory work on the deformation of mantle minerals at high pressures. We consider the effects of the strength of the slab using two-dimensional calculations of a slab-like thermal downwelling with an endothermic phase change. Because the rheology and composition of subducting slabs are uncertain, we consider a range of Clapeyron slopes which bound current laboratory estimates of the spinel to perovskite plus magnesiowustite phase transition and simple temperature-dependent rheologies based on an Arrhenius law diffusion mechanism. In uniform viscosity convection models, subducted material piles up above the phase change until the pile becomes gravitationally unstable and sinks into the lower mantle (the avalanche). Strong slabs moderate the 'catastrophic' effects of the instabilities seen in many constant-viscosity convection calculations; however, even in the strongest slabs we consider, there is some retardation of the slab descent due to the presence of the phase change.

King, S. D.; Ita, J. J.; Staudigel, H.

1994-01-01

157

First volatile inventory for Gorely volcano, Kamchatka  

NASA Astrophysics Data System (ADS)

We report here the very first assessment of volatile flux emissions from Gorely, an actively degassing volcano in Kamchatka. Using a variety of in situ and remote sensing techniques, we determined the bulk plume concentrations of major volatiles (H2O ˜93.5%, CO2, ˜2.6%, SO2 ˜2.2%, HCl 1.1%, HF 0.3%, H2 0.2%) and trace-halogens (Br, I), therefore estimating a total gas release of ˜11,000 tons·day-1 during September 2011, at which time the target was non-eruptively degassing at ˜900°C. Gorely is a typical arc emitter, contributing 0.3% and 1.6% of the total global fluxes from arc volcanism for CO2 and HCl, respectively. We show that Gorely's volcanic gas (H2O/SO2 ˜43, CO2/SO2 ˜1.2, HCl/SO2 ˜0.5) is a representative mean end-member for arc magmatism in the north-west Pacific region. On this basis we derive new constraints for the abundances and origins of volatiles in the subduction-modified mantle source which feeds magmatism in Kamchatka.

Aiuppa, A.; Giudice, G.; Liuzzo, M.; Tamburello, G.; Allard, P.; Calabrese, S.; Chaplygin, I.; McGonigle, A. J. S.; Taran, Y.

2012-03-01

158

Plant Volatile Analogues Strengthen Attractiveness to Insect  

PubMed Central

Green leaf bug Apolygus lucorum (Meyer-Dür) is one of the major pests in agriculture. Management of A. lucorum was largely achieved by using pesticides. However, the increasing population of A. lucorum since growing Bt cotton widely and the increased awareness of ecoenvironment and agricultural product safety makes their population-control very challenging. Therefore this study was conducted to explore a novel ecological approach, synthetic plant volatile analogues, to manage the pest. Here, plant volatile analogues were first designed and synthesized by combining the bioactive components of ?-ionone and benzaldehyde. The stabilities of ?-ionone, benzaldehyde and analogue 3 g were tested. The electroantennogram (EAG) responses of A. lucorum adult antennae to the analogues were recorded. And the behavior assay and filed experiment were also conducted. In this study, thirteen analogues were acquired. The analogue 3 g was demonstrated to be more stable than ?-ionone and benzaldehyde in the environment. Many of the analogues elicited EAG responses, and the EAG response values to 3 g remained unchanged during seven-day period. 3 g was also demonstrated to be attractive to A. lucorum adults in the laboratory behavior experiment and in the field. Its attractiveness persisted longer than ?-ionone and benzaldehyde. This indicated that 3 g can strengthen attractiveness to insect and has potential as an attractant. Our results suggest that synthetic plant volatile analogues can strengthen attractiveness to insect. This is the first published study about synthetic plant volatile analogues that have the potential to be used in pest control. Our results will support a new ecological approach to pest control and it will be helpful to ecoenvironment and agricultural product safety. PMID:24911460

Sun, Yufeng; Yu, Hao; Zhou, Jing-Jiang; Pickett, John A.; Wu, Kongming

2014-01-01

159

ANALYSIS OF VOLATILE COMPOUNDS FROM INFUSION AND HYDRODISTILLATE OBTAINED FROM THE SPECIES THYMUS PULEGIOIDES L. (LAMIACEAE)  

Microsoft Academic Search

The volatile compounds present in the species belonging to the Thymus genus (Lamiaceae) are responsible for the two well defined therapeutic effects demonstrated for these plants: antiseptic and spasmolytic effects. The essential oil which contains the majority of these compounds is hardly accessible and, as consequence, it is rarely used by the patient. That's why an analysis of the volatile

MARIANA PAVEL; ANA TEODOR; Carol Davila

2009-01-01

160

Syrtis Major  

NASA Astrophysics Data System (ADS)

A prominent dark, triangular albedo feature (dark by contrast with its surroundings) on the Martian equator, centered approximately at 10 °N, 70 °E. It takes its name from the historical name for the larger of two quicksands off the North African coast. Syrtis Major is prominent in telescopic views of the planet, and was in fact the first feature of Mars ever to be recorded, in a sketch made by C...

Murdin, P.

2000-11-01

161

Major ion chemistry of the Yarlung Tsangpo-Brahmaputra river: Chemical weathering, erosion, and CO 2 consumption in the southern Tibetan plateau and eastern syntaxis of the Himalaya  

NASA Astrophysics Data System (ADS)

The Yarlung Tsangpo-Brahmaputra river drains a large portion of the Himalaya and southern Tibetan plateau, including the eastern Himalayan syntaxis, one of the most tectonically active regions on the globe. We measured the solute chemistry of 161 streams and major tributaries of the Tsangpo-Brahmaputra to examine the effect of tectonic, climatic, and geologic factors on chemical weathering rates. Specifically, we quantify chemical weathering fluxes and CO 2 consumption by silicate weathering in southern Tibet and the eastern syntaxis of the Himalaya, examine the major chemical weathering reactions in the tributaries of the Tsangpo-Brahmaputra, and determine the total weathering flux from carbonate and silicate weathering processes in this region. We show that high precipitation, rapid tectonic uplift, steep channel slopes, and high stream power generate high rates of chemical weathering in the eastern syntaxis. The total dissolved solids (TDS) flux from the this area is greater than 520 tons km -2 yr -1 and the silicate cation flux more than 34 tons km -2 yr -1. In total, chemical weathering in this area consumes 15.2 × 10 5 mol CO 2 km -2 yr -1, which is twice the Brahmaputra average. These data show that 15-20% of the total CO 2 consumption by silicate weathering in the Brahmaputra catchment is derived from only 4% of the total land area of the basin. Hot springs and evaporite weathering provide significant contributions to dissolved Na + and Cl - fluxes throughout southern Tibet, comprising more than 50% of all Na + in some stream systems. Carbonate weathering generates 80-90% of all dissolved Ca 2+ and Mg 2+ cations in much of the Yarlung Tsangpo catchment.

Hren, Michael T.; Chamberlain, C. Page; Hilley, George E.; Blisniuk, Peter M.; Bookhagen, Bodo

2007-06-01

162

Arsenic(III, V) adsorption on a goethite-based adsorbent in the presence of major co-existing ions: Modeling competitive adsorption consistent with spectroscopic and molecular evidence  

NASA Astrophysics Data System (ADS)

Adsorption of the two oxyanions, arsenate (As(V)) and arsenite (As(III)), on a common goethite-based granular porous adsorbent is studied in the presence of major co-existing ions in groundwater (i.e., phosphate, silicic acid, sulfate, carbonate, magnesium, and calcium) and predicted using the extended triple layer model (ETLM), a dipole modified single-site triple layer surface complexation model consistent with spectroscopic and molecular evidence. Surface species of all ions were selected according to the previous ETLM studies and published experimental spectroscopic/theoretical molecular information. The adsorption equilibrium constants for all ions were determined using adsorption data obtained in single-solute systems. The adsorption equilibrium constants referenced to the site-occupancy standard state (indicated by K?) were compared with those for goethite in the literature if available. The values of these constants for the goethite-based adsorbent are found to be close to the values for goethite previously studied. These "constrained" adsorption equilibrium constants determined in single-solute systems were used in the ETLM to predict the competitive interactions of As(III, V) with the co-existing ions in binary-solute systems. The ETLM is capable of predicting As(III, V) adsorption in the presence of oxyanions (phosphate, silicic acid, sulfate, and carbonate). This study presents the first successful and systematic prediction of the competitive interactions of As(III, V) with these oxyanions using the ETLM. The ETLM prediction of surface (and aqueous) speciation also provides insights into the distinct adsorption behavior of As(III, V) in the presence of the oxyanions. Magnesium and calcium significantly enhanced As(V) adsorption at higher pH values, while they had little effect on As(III) adsorption. The enhanced adsorption of As(V), however, could not be predicted by the ETLM using the surface species proposed in previous ETLM studies. Further studies are necessary to identify ternary complexes, especially at high pH. Adsorption isotherms of As(V), a dominant form of arsenic in adsorptive water treatment systems, in the presence of the co-existing ions under relevant conditions of water treatment systems are also obtained and predicted by the ETLM to study and compare the effect of the co-existing ions on As(V) removal.

Kanematsu, Masakazu; Young, Thomas M.; Fukushi, Keisuke; Green, Peter G.; Darby, Jeannie L.

2013-04-01

163

Fig volatile compounds—a first comparative study  

Microsoft Academic Search

We analysed the compounds of volatile blends released by receptive figs of twenty Ficus species to attract their specific pollinating wasps. In all, 99 different compounds were identified. The compounds are mainly terpenoids, aliphatic compounds and products from the shikimic acid pathway. In each species blend, there are few major compounds, which are generally common among floral fragrances. Most species

Laure Grison-Pigé; Martine Hossaert-McKey; Jaco M. Greeff; Jean-Marie Bessière

2002-01-01

164

Volatile Constituents of the Flowers of Dipteryx odorata (Aubl.) Willd  

Microsoft Academic Search

The chemical composition of the volatile concentrates of the flowers of Dipteryx odorata, the cumaru (tonka) tree of the Amazon, was obtained by simultaneous distillation-extraction and analyzed by GC and GC\\/MS. The major components identified were germacrene D (31.1%), bicyclogermacrene (13.0%) and spathulenol (11.3%).

Eloisa Helena A. Andrade; Maria das Graças B. Zoghbi; Léa Maria M. Carreira; José Guilherme S. Maia

2003-01-01

165

Syrtis Major  

NASA Technical Reports Server (NTRS)

(Released 1 May 2002) The Science This image is from the region of Syrtis Major, which is dominated by a low-relief shield volcano. This area is believed to be an area of vigorous aeolian activity with strong winds in the east-west direction. The effects of these winds are observed as relatively bright streaks across the image, extending from topographic features such as craters. The brighter surface material probably indicates a smaller relative particle size in these areas, as finer particles have a higher albedo. The bright streaks seen off of craters are believed to have formed during dust storms. A raised crater rim can cause a reduction in the wind velocity directly behind it, which results in finer particles being preferentially deposited in this location. In the top half of the image, there is a large bright streak that crosses the entire image. There is no obvious topographic obstacle, therefore it is unclear whether it was formed in the same manner as described above. This image is located northwest of Nili Patera, a large caldera in Syrtis Major. Different flows from the caldera eruptions can be recognized as raised ridges, representing the edge of a flow lobe. The Story In the 17th century, Holland was in its Golden Age, a time of cultural greatness and immense political and economic influence in the world. In that time, lived a inquisitive person named Christian Huygens. As a boy, he loved to draw and to figure out problems in mathematics. As a man, he used these talents to make the first detailed drawings of the Martian surface - - only 50 years or so after Galileo first turned his telescope on Mars. Mars suddenly became something other than a small red dot in the sky. One of the drawings Huygens made was of a dark marking on the red planet's surface named Syrtis Major. Almost 350 years later, here we are with an orbiter that can show us this place in detail. Exploration lives! It's great we can study this area up close. In earlier periods of history, scientists were fascinated with Syrtis Major because this dark region varied so much through the seasons and years. Some people thought it might be a changing sea, and others thought it might be vegetation. Early spacecraft like Mariner and Viking revealed for the first time that the changes were caused by the wind blowing dust and sand across the surface. What we can see in this image is exactly that: evidence of a lot of wind action. Bright dust patches streak across this image, formed through wind interference from craters and other landforms. These wispy, bright streaks are spread on the surface by a vigorous, east-west wind that kicked up huge dust storms, scattering the fine particles of sand and dust in an almost etherial pattern. The bright streaks in the top part of the image might have formed in a slightly different way, because there is no landform standing in the wind's way. Beneath the bright surface dust are raised ridges that mark the edges of earlier lava flows from Nili Patera, a Martian 'caldera.' A caldera is a collapsed, bowl-shaped depression at the top of a volcano cone. Can you imagine how Christian Huygens would feel if he lived today and could see all of this knowledge unfold? Or how it would feel to be the first person to stand in this dark volcanic and cratered region, knowing how many discovers had paved the way to that moment? Yes, exploration lives!

2002-01-01

166

The distillation and volatility of ionic liquids  

NASA Astrophysics Data System (ADS)

It is widely believed that a defining characteristic of ionic liquids (or low-temperature molten salts) is that they exert no measurable vapour pressure, and hence cannot be distilled. Here we demonstrate that this is unfounded, and that many ionic liquids can be distilled at low pressure without decomposition. Ionic liquids represent matter solely composed of ions, and so are perceived as non-volatile substances. During the last decade, interest in the field of ionic liquids has burgeoned, producing a wealth of intellectual and technological challenges and opportunities for the production of new chemical and extractive processes, fuel cells and batteries, and new composite materials. Much of this potential is underpinned by their presumed involatility. This characteristic, however, can severely restrict the attainability of high purity levels for ionic liquids (when they contain poorly volatile components) in recycling schemes, as well as excluding their use in gas-phase processes. We anticipate that our demonstration that some selected families of commonly used aprotic ionic liquids can be distilled at 200-300°C and low pressure, with concomitant recovery of significant amounts of pure substance, will permit these currently excluded applications to be realized.

Earle, Martyn J.; Esperança, José M. S. S.; Gilea, Manuela A.; Canongia Lopes, José N.; Rebelo, Luís P. N.; Magee, Joseph W.; Seddon, Kenneth R.; Widegren, Jason A.

2006-02-01

167

Investigation of Ionized Volatiles and Interior Structure of the Moon: Implications from Restored Apollo Magnetic Field Data  

NASA Astrophysics Data System (ADS)

The restored Apollo magnetic field data have revealed ion cyclotron waves that suggest the presence of ionized volatiles from the Moon. Further restoration of the Apollo-era data can help probe the electrical conductivity of the lunar interior.

Chi, P. J.

2014-10-01

168

TREATMENT OF CHLORINATED VOLATILE ORGANIC COMPOUNDS IN UPFLOW WETLAND MESOCOSMS. (R828773C003)  

EPA Science Inventory

Sorption, biodegradation and hydraulic parameters were determined in the laboratory for two candidate soil substrate mixtures for construction of an upflow treatment wetland for volatile organic compounds (VOCs) at a Superfund site. The major parent contaminants in the groundw...

169

Volatile components of ethanolic extract from broccolini leaves.  

PubMed

Broccolini (Brassica oleracea Italica?×?Alboglabra) is a hybrid of broccoli and kai-lan, Chinese broccoli. To date, no study has been reported on the chemical composition of the volatile fractions of this raw material. In this study, the volatile constituents from the ethanolic extract of broccolini leaves were analysed by gas chromatography-mass spectrometry (GC-MS). Sixteen compounds were identified. The major components include 5-phenyl-undecane (11%), n-hexadecanoic acid (9.34%), octadecanoic acid (6.39%), 1,1,3-trimethyl-3-phenyl-indan (4.0%), 3-(2-phenylethyl)benzonitrile (3.48%) and phytol (3.37%). PMID:21859369

Wang, Xiaoqin; Zhang, Bochao; Wang, Bingfang; Zhang, Xuewu

2012-01-01

170

Ion Trap Mass Spectrometry  

SciTech Connect

This chapter describes research conducted in a few research groups in the 1990s in which RF quadrupole ion trap mass spectrometers were coupled to a powerful atomic ion source, the inductively coupled plasma used in conventional ICP-MS instruments. Major section titles for this chapter are: RF Quadrupole Ion Traps Features of RF Quadrupole Ion Trap Mass Spectrometers Selective Ion Trapping methods Inductively Coupled Plasma Source Ion Trap Mass Spectrometers

Eiden, Greg C.

2005-09-01

171

Surface application of ammonium thiosulfate fertilizer to reduce volatilization of 1,3-dichloropropene from soil  

Microsoft Academic Search

Atmospheric emission of the soil fumigant 1,3-dichloropropene (1,3-D) is of environmental concern because of its toxicity and carcinogenicity. Thiosulfate fertilizers have been found to rapidly transform 1,3-D in soil to non-volatile ions which are less toxic. We investigated the use of surface application of ammonium thiosulfate (ATS) for reducing 1,3-D volatilization. In packed soil columns, emission of 1,3-D applied by

Jianying Gan; J Ole Becker; Frederick F Ernst; Chad Hutchinson; James A Knuteson; Scott R Yates

2000-01-01

172

High density silicon nanocrystal embedded in sin prepared by low energy (<500eV) SiH\\/sub 4\\/ plasma immersion ion implantation for non-volatile memory applications  

Microsoft Academic Search

We report on the excellent memory properties of silicon nanocrystals (Si-NCs) embedded in SiN. Si-NCs were formed by SiH4 low-energy plasma immersion ion implantation. Compared with control Si+-implanted sample, additional hydrogen enhanced Si-NC density. By incorporating Si-NCs in SiN, improved program\\/erase efficiency, endurance and retention characteristics were observed due to the generation of additional accessible deep charge traps. Using conductive

Sangmoo Choi; Hyejung Choi; Tae-Wook Kim; Hyundeok Yang; Takhee Lee; Sanghun Jeon; Chungwoo Kim; Hyunsang Hwang

2005-01-01

173

Study of cesium volatility from sodium carbonate based melts  

SciTech Connect

Purpose of this study was to obtain thermodynamic data on cesium volatility from sodium carbonate-based molten salts for application to the Rockwell-ETEC molten salt oxidation process. At 1073 to 1373 K, volatility tests were conducted on a horizontal and a vertical transpiration apparatus using a carrier gas composed of CO{sub 2}(g) and H{sub 2}O(g) which was passed over or bubbled through a sodium carbonate bath containing cesium carbonate and various additives. The major vapor species was identified to be CsOH(g) except when greater than 3% chloride is present in the melt, then the major vapor species is CsCl(g). The decrease in volatility of cesium as a function of cesium concentration in Cs{sub 2}CO{sub 3{minus}}Na{sub 2}CO{sub 3} mixtures follows Raoult`s law very closely. Thus, this system exhibits close to ideal solution behavior. Addition of 22.5 wt % sodium sulfate decreases the cesium volatility by just under a factor of 2, and the addition of 10.0 wt % sodium chloride increases the cesium volatility about an order of magnitude. The addition of 2.0 wt % ash, molecular sieve, or silica show little or no effect. However, the data indicate that higher concentrations of ash will decrease the cesium volatility. For the addition of 22.5 wt % sodium sulfate the activity coefficient, {gamma}(Cs{sub 2}CO{sub 3}){sup {1/2}}, is calculated to be 0.720 {plus_minus} 0.068, and for the addition of 10.0 wt % sodium chloride, the activity coefficient, {gamma}(CsCl), is calculated to be 8.118 {plus_minus} 2.317. Assuming that Henry`s law applies, these activity coefficients are used to extrapolate the effect on cesium retention in the molten salt oxidizer of sulfate and chloride at lower cesium concentrations.

Ebbinghaus, B.B.; Krikorian, O.H.; Adamson, M.G.; Fleming, D.L.

1993-12-01

174

Identification of a volatile phytotoxin from algae  

NASA Technical Reports Server (NTRS)

The objectives were to develop a trap system for isolating fractions of volatile algal phytotoxin and to characterize the major components of the isolated phytotoxin fractions. A bioassay using Phaseolus vulgaris seedlings was developed to aid in investigating the properties of the phytotoxin produced by cultures of Euglena gracilis var. bacillaris and Chlorella vulgaris. Two traps were found, 1.0 M hydrochloric acid and 0 C, which removed the phytotoxin from the algal effluent and which could be treated to release that phytotoxin as judged with the bioassay procedure. It was also determined that pretraps of 1.0 M sodium hydroxide and 1.0 M potassium biocarbonate could be used without lowering the phytotoxin effect. Ammonia was identified in trap solutions by ninhydrin reaction, indophenol reaction and derivatization with dansyl chloride and phenylisothiocyanate. Ammonia at the gaseous concentrations detected was found to have the same effects in the bioassay system as the volatile phytotoxin. It is possible that other basic, nitrogen containing compounds which augment the effects of ammonia were present at lower concentrations in the algal effluent.

Garavelli, J. S.; Fong, F.; Funkhouser, E. A.

1984-01-01

175

Comets, volcanism, the salt-rich regolith, and cycling of volatiles on Mars  

NASA Astrophysics Data System (ADS)

Estimates of the total inventory of the volatile elements C, H, O, and N on Mars, based upon atmospheric gas tracers, vary by a factor of 25 among different authors. Accretion of comets as the source of volatiles can account for less than 5% of the actual inventory, assuming the chondritic S/Cl abundance ratio in comets and a Martian outgassing ratio for these two elements no lower than for the estimated excess volatile inventory on Earth. Sulfate salt formation with the igneous minerals in the regolith can be a major sink for H2O, but first will recycle C and N incorporated in carbonate and nitrate minerals back to the atmosphere. Extrusive and shallow intrusive volcanism, at a persistent but decreasing rate, can interfere with this volatile recycling by irreversibly masking much of the incorporated inventory, resulting in the inevitable evolution to a relatively volatile-poor environment at the outermost, observable surface of Mars.

Clark, B. C.

1987-08-01

176

Volatile halogenated hydrocarbons in foods  

Microsoft Academic Search

Volatile halogenated organic compounds were determined in foods. Statistical treatment of the data for 13 sampled from 20 families living in suburban Tokyo (Saitama prefecture) indicated that the foods were contaminated by water pollution and\\/or substances introduced by the process of food production. Butter and margarine were contaminated by chlorinated ethylene, ethane, and related compounds released by dry cleaning and

Makoto Miyahara; Masatake Toyoda; Yukio Saito

1995-01-01

177

5, 463499, 2008 Oxygenated volatiles  

E-print Network

of flooding on the exchange of the volatile C2-compounds ethanol, acetaldehyde and acetic acid between leaves and acetic acid was investigated with 2­3 years old tree seedlings of four Amazonian floodplain species significant emissions of any of the compounds. A slight deposition of acetaldehyde and acetic acid was mainly

Boyer, Edmond

178

Martian Solids with Volatile Elements  

NASA Astrophysics Data System (ADS)

Martian solids in air planet are mixed with quenched volatile elemnets remained in the interior,comparwed with water planet Earth and life materials. The mixed solids on Mars are easily changed to gas and/or fluids by impac-related processes shortly.

Miura, Y.; Tanosaki, T.

2014-11-01

179

Pyrolysis and volatilization of cocaine  

SciTech Connect

The increasing popularity of inhaling cocaine vapor prompted the present study, to determine cocaine's fate during this process. The free base of (3H)cocaine (1 microCi/50 mg) was added to a glass pipe, which was then heated in a furnace to simulate freebasing. Negative pressure was used to draw the vapor through a series of glass wool, ethanol, acidic, and basic traps. Air flow rate and temperature were found to have profound effects on the volatilization and pyrolysis of cocaine. At a temperature of 260 degrees C and a flow rate of 400 mL/min, 37% of the radioactivity remained in the pipe, 39% was found in the glass wool trap, and less than 1% in the remainder of the volatilization apparatus after a 10-min volatilization. Reducing the air flow rate to 100 mL/min reduced the amount of radioactivity collected in the glass wool trap to less than 10% of the starting material and increased the amount that remained in the pipe to 58%. GC/MS analysis of the contents of the glass wool trap after volatilization at 260 degrees C and a flow rate of 400 mL/min revealed that 60% of the cocaine remained intact, while approximately 6 and 2% of the starting material was recovered as benzoic acid and methylecgonidine, respectively. As the temperature was increased to 650 degrees C, benzoic acid and methylecgonidine accounted for 83 and 89% of the starting material, respectively, whereas only 2% of the cocaine remained intact. Quantitation of cocaine in the vapor during the course of volatilization revealed high concentrations during the first two min and low concentrations for the remaining time.

Martin, B.R.; Lue, L.P.; Boni, J.P. (Virginia Commonwealth Univ., Richmond (USA))

1989-05-01

180

Optimal portfolios when volatility can jump  

Microsoft Academic Search

We consider an asset allocation problem in a continuous-time model with stochastic volatility and jumps in both the asset price and its volatility. First, we derive the optimal portfolio for an investor with constant relative risk aversion. The demand for jump risk includes a hedging component, which is not present in models without volatility jumps. We further show that the

Nicole Branger; Christian Schlag; Eva Schneider

2008-01-01

181

Forecasting Volatility in Financial Markets: A Review  

Microsoft Academic Search

Financial market volatility is an important input for investment, option pricing, and financial market regulation. The emphasis of this review article is on forecasting instead of modelling; it compares the volatility forecasting findings in 93 papers published and written in the last two decades. Provided in this paper as well are volatility definitions, insights into problematic issues of forecast evaluation,

Ser-Huang Poon; Clive W. J. Granger

2003-01-01

182

Financial openness and business cycle volatility  

Microsoft Academic Search

This paper discusses whether the integration of international financial markets affects business cycle volatility. In the framework of a new open economy macro-model, we show that the link between financial openness and business cycle volatility depends on the nature of the underlying shock. Empirical evidence supports this conclusion. Our results also show that the link between business cycle volatility and

Claudia M. Buch; Joerg Doepke; Christian Pierdzioch

2005-01-01

183

The Role of Volatility in Forecasting  

Microsoft Academic Search

Theories of underinvestment propose a link between cash flow volatility and investment and subsequent cash flow and earnings levels. Consistent with these theories, our results indicate that forecasting models that include volatility as an explanatory variable have greater accuracy and lower bias than forecasting models that exclude volatility. The improvement in forecast accuracy and bias is greatest when the firm

Bernadette A. Minton; Catherine M. Schrand; Beverly R. Walther

2002-01-01

184

Volatile Semiochemicals Released from Undamaged Cotton Leaves  

Microsoft Academic Search

Cotton plants (Gossypium hirsutum L.), attacked by herbivorous insects release volatile semiochemicals (chemical signals) that at- tract natural enemies of the herbivores to the damaged plants. We found chemical evidence that volatiles are released not only at the damaged site but from the entire cotton plant. lhe release of volatiles was detected from upper, undamaged leaves after 2 to 3

Ursula S. R. Rose; Ara Manukian; Robert R. Heath; James H. Tumlinson

185

Volatility Forecasting: The Jumps Do Matter  

Microsoft Academic Search

This study reconsiders the role of jumps for volatility forecasting by showing that jumps have a positive and mostly significant impact on future volatility. This result becomes apparent once volatility is correctly separated into its continuous and discontinuous component. To this purpose, we introduce the concept of threshold multipower variation (TMPV), which is based on the joint use of bipower

Fulvio Corsi; Davide Pirino; Roberto Reno

2009-01-01

186

Inhibition of prostate cancer (LNCaP) cell proliferation by volatile components from Nagami kumquats.  

PubMed

Fresh Nagami kumquats (Fortunella margarita) were subjected to hydrodistillation using a Clevenger-type apparatus to obtain volatile oil. The chemical composition of the volatile oil was analyzed by GC-MS using Rtx-5 Sil MS and DB Wax columns. A total of 25 volatile compounds were identified by mass spectra, retention index, and comparison with known standards. The major identified compounds are d-limonene (41.64 %), ?-myrecene (16.54 %), linalyl propionate (9.55 %), and germacrene-D (5.93 %) from the Rtx-5 Sil MS column; d-limonene and ?-myrecene were also separated as major compounds on the DB wax column. The oil is rich in hydrocarbons (77.41 %) consisting of 60.05 % monoterpenes and 17.36 % sesquiterpenes. Interestingly, oxygenated hydrocarbons (17.6 %) were also found in kumquat volatile oil. Certain volatile compounds were also confirmed by positive chemical ionization and NMR spectra. Further, the volatile oil demonstrated good DPPH radical scavenging activity and antioxidant capacity. Kumquat volatile oil at 200 ppm concentration exhibited 55 %, 61 %, and 63.4 % inhibition of human prostate cancer (LNCaP) cell proliferation at 24, 48, and 72 h, respectively, by cell count assays. Significant increases in expression of bax/bcl2 and p53 proteins confirmed that volatile oil induces apoptosis. In addition, inhibition of inflammatory markers such as NF-?B and Cox-2 was observed. The cleavage of caspase-8 in the LNCaP cells treated with volatile oil demonstrated that apoptosis occurred through an extrinsic pathway. This is the first report of the identification and possible mechanisms of in vitro antiproliferative effects of kumquat volatile components on human prostate cancer (LNCaP) cells. PMID:22673830

Jayaprakasha, Guddadarangavvanahally K; Murthy, Kotamballi N Chidambara; Demarais, Rock; Patil, Bhimanagouda S

2012-06-01

187

Volatile fraction of lavender and bitter fennel infusion extracts.  

PubMed

The relative proportions of chemical classes (hydrocarbons, oxides, alcohols/ethers, aldehydes/ketones, acids/esters/lactones) in the essential oil of lavender (Lavendula angustifolia Mill., family Lamiaceae) and bitter fennel (Foeniculum vulgare Mill. subsp. vulgare var. vulgare (Mill.) Thellung, family Apiaceae) and in the volatile fraction of infusion extracts were examined and showed remarkable differences. The volatile compounds of infusions were isolated by hydrodistillation and solid phase extraction (SPE). Their qualitative and semiquantitative compositions were compared with the essential oil isolated by hydrodistillation directly from the plant material and analyzed by GC-MS. Furthermore, quantification of the major constituents of lavender oil and of the volatile fraction obtained by hydrodistillation of the infusion was performed. Comparison of the total essential oil yield quantified by hydrodistillation of the lavender infusion (0.7% v/w, corresponding to plant material) with the essential oil yield of the blossoms (5.1% v/w) revealed that only 13.9% of the initial oil could be extracted by infusion. The main constituents of the volatile fraction of the lavender infusion were (hydrodistillation/SPE): linalool (39.3%/28.2%), 1,8 cineole (24.8%/18.9%), cis-linalool oxide (furanoid) (5.8%/8.0%), trans-linalool oxide (furanoid) (4.1%/7.1%), camphor (5.3%/4.0%) and alpha-terpineol (4.0%/3.0%). The major constituents of lavender essential oil were linalool (28.8%), 1,8-cineole (18.05%), linalyl acetate (13.9%) and alpha-terpineol (4.0%). Most intriguing, in the volatile fraction of lavender infusion a significant proportional decrease of linalyl acetate and an increase of linalool oxides was recognized. The essential oil yield of fennel fruits was 12.5% v/w, whereas 1.8% v/w volatile fraction (corresponding to plant material) was obtained by hydrodistillation of the fennel infusion, which is equivalent to 14.5% of the initial fennel essential oil. The main constituents of the volatile fraction of the fennel infusion were (hydrodistillation/SPE): trans-anethole (56.4%/54.8%), fenchone (36.2%/39.5%) and estragole (2.5%/2.2%), which were also the major compounds of the genuine bitter fennel essential oil. In infusions, the proportion of ethers vs. ketones was shifted significantly towards a higher proportion of the latter compared with the essential oil obtained from the fruits. PMID:20923003

Tschiggerl, Christine; Bucar, Franz

2010-09-01

188

Direct injection ion chromatography for the control of chlorinated drinking water: simultaneous estimation of nine haloacetic acids and quantitation of bromate, chlorite and chlorate along with the major inorganic anions.  

PubMed

Most methods for the analysis of haloacetic acids published in recent years are based on ion chromatography with direct injection, employing a gradient elution with potassium hydroxide (KOH). This work reports the exploration of an alternative eluent, a buffer of sodium carbonate/sodium hydrogen carbonate, aimed at the simultaneous analysis of nine haloacetic acids along with bromate, chlorite and chlorate. The alternative of both a less alkaline eluent and a lower temperature of operation may prevent the partial decomposition of some of the haloacetic acids during the analytical process, especially the more vulnerable brominated ones. Gradient elution at temperature of 7 °C yielded the best results, with an acceptable separation of 17 analytes (which includes the major natural inorganic anions) and a good linearity. Precision ranges from 0.3 to 23.4 (% V.C.), and detection limits are within units of ?g L?¹, except for tribromoacetic acid - somewhat high in comparison with those of the official methods. Nonetheless, with the basic instrumentation setup herein described, this method may be suitable for monitoring when the drinking water treatments are to be optimized. This is especially interesting for small communities or for developing/developed countries in which regulations on disinfection by-products others than trihalomethanes are being addressed. PMID:25252348

Garcia-Villanova, Rafael J; Raposo Funcia, César; Oliveira Dantas Leite, M Vilani; Toruño Fonseca, Ivania M; Espinosa Nieto, Miguel; Espuelas India, Javier

2014-09-01

189

Color and volatile analysis of peanuts roasted using oven and microwave technologies.  

PubMed

Roasted peanut color and volatiles were evaluated for different time and temperature combinations of roasting. Raw peanuts were oven roasted at 135 to 204 °C, microwave roasted for 1 to 3 min, or combination roasted by microwave and oven roasting for various times and temperatures. Volatiles were measured using selected ion flow tube mass spectrometry. L* values were used to categorize peanuts as under-roasted, ideally roasted, and over-roasted. The total roasting time in order to achieve ideal color was not shortened by most of the combination treatments compared to their oven roasted equivalents. Oven before microwave roasting compared to the reverse was found to significantly increase the L* value. Peanuts with the same color had different volatile levels. Hexanal concentrations decreased then increased with roasting. Pyrazine levels increased as roasting time increased, although oven at 177 °C treatments had the highest and microwave treatments had the lowest levels. Volatile levels generally increased as roasting time or temperature increased. Oven 177 °C for 15 min generally had the highest level of volatiles among the roasting treatments tested. Soft independent modeling of class analogies based on volatile levels showed that raw peanuts were the most different, commercial samples were the most similar to each other, and oven, microwave, and combination roasting were all similar in volatile profile. PMID:25182117

Smith, Alicia L; Barringer, Sheryl A

2014-10-01

190

Volatile substance misuse : clinical considerations, neuropsychopharmacology and potential role of pharmacotherapy in management.  

PubMed

Volatile substance misuse is among the most prevalent and toxic forms of psychoactive drug use, and often results in highly deleterious social, psychological and medical consequences. The prevalence of this pernicious form of substance misuse owes in part to the fact that volatile substances of misuse are ubiquitous in the natural environment. Commonly misused commercial products include glue, shoe polish, nail polish remover, butane lighter fluid, gasoline and computer duster spray. National samples of volatile substance misusers tend to exhibit high rates of psychiatric problems and antisocial behaviour. In addition, cognitive impairments and affective dysregulation are often observed among these individuals. Volatile substances exert their complex neuropharmacological effects on dopaminergic, glutamatergic, GABAergic and serotoninergic receptor systems, as well as on cell membranes and ion channels. Concomitantly, pharmacotherapies for volatile substance abuse might profitably target a number of mechanisms, including reward circuitry in the brain, symptoms of craving and withdrawal, neuropsychiatric and emotional impairments that promote volatile substance abuse, and cognitive enhancement to rectify deficits in executive function. This review details the modes of use, subjective effects, epidemiology, adverse consequences, neuropsychopharmacology and drug treatment of volatile substance misuse, and discusses the potential role of novel forms of pharmacological intervention for this oft-overlooked public health threat of epidemic proportions. PMID:23018545

Garland, Eric L; Howard, Matthew O

2012-11-01

191

The Volatility of Liquidity and Expected Stock Returns  

E-print Network

Ekkehart Boehmer Committee Members, Michael F. Gallmeyer Asqhar Zardkoohi Head of Department, Sorin M. Sorescu August 2011 Major Subject: Finance iii ABSTRACT The Volatility of Liquidity and Expected Stock Returns. (August 2011... for periods of high liquidity to sell. v ACKNOWLEDGEMENTS I would like to thank my advisors, Dr. Sorin Sorescu, Dr Ekkehart Boehmer, and Dr. Michael Gallmeyer, for their support and guidance throughout the course of this research. I also want...

Akbas, Ferhat 1981-

2011-07-29

192

Fig volatile compounds—a first comparative study  

Microsoft Academic Search

Abstract We analysed the compounds,of volatile blends released by receptive figs of twenty Ficus species to attract their specific pollinating wasps.In all, 99 different compounds were identified.The compounds are mainly terpenoids, aliphatic compounds and products from the shikimic acid pathway.In each species blend, there are few major compounds, which are generally common among floral fragrances. Most species blends also include

Laure Grison-pige; Martine Hossaert-mckey; Jaco M. greeff; Jean-marie Bessie Re

193

Volatile components of Discaria americana Gillies & Hook (Rhamnaceae)  

Microsoft Academic Search

The volatile fraction from aerial parts (flowers, stems and leaves) of Discaria americana Gillies & Hook (Rhamnaceae) was obtained by hydrodistillation and the chemical composition of this oil was determined by gas chromatography and gas chromatography–mass spectrometry. The major constituents resulted to be 4-methylphenol (15.5%), eugenol (11%), 3-methylindole (9.7%) and ?-terpineol (6.2%). The essential oil of this plant displayed strong

Silvana Rodriguez; Ana Paula Murray

2008-01-01

194

Volatile Compounds in Cider: Inoculation Time and Fermentation Temperature Effects  

Microsoft Academic Search

J. Inst. Brew. 112(3), 210-214, 2006 A cider fermentation at laboratory scale with controlled inocula- tion with selected yeasts and malolactic bacteria was performed. The composition of the major volatile compounds with low boil- ing points (<145°C) was determined by gas chromatography throughout the fermentation process, under the different operat- ing conditions of inoculation time of the microorganisms (simul- taneous

Mónica Herrero; Luis A. García; Mario Díaz

195

Childhood income volatility and adult outcomes.  

PubMed

Using data linked across generations in the Panel Study of Income Dynamics, I estimate the relationship between exposure to volatile income during childhood and a set of socioeconomic outcomes in adulthood. The empirical framework is an augmented intergenerational income mobility model that includes controls for income volatility. I measure income volatility at the family level in two ways: (1) instability as measured by squared deviations around a family-specific mean; and (2) instability as percentage changes of 25 % or more. Volatility enters the model both separately and interacted with income level. I find that family income volatility during childhood has a modest negative association with educational attainment. Volatility has a smaller descriptive role in explaining intergenerational outcomes relative to permanent income. Across the income distribution, the negative association between volatility exposure and educational attainment is largest for young adults from moderate-income families. PMID:25280839

Hardy, Bradley L

2014-10-01

196

Volatiles in interplanetary dust particles  

NASA Technical Reports Server (NTRS)

Interplanetary dust particles (IDP's) collected by specially equipped aircraft flying in the stratosphere have generated a lot of interest during the last decade. These particles, consisting of primitive materials originating in small solar system bodies such as comets and asteroids, are complex heterogeneous species with a variety of components. In order to understand the past histories of IDP's, it is particularly important to know the nature of the volatiles present. Volatiles released from a number of IDP's have been studied; however, a large number of particles must be studied in order to establish trends, to classify types of IDP's, and to have comparison data for determining the origins of IDP's. This study involves the analysis of six IDP's using laser microprobe mass spectrometry.

Bustin, Roberta

1991-01-01

197

Evolution of Io's volatile inventory  

SciTech Connect

Voyager data are used to make crude estimates of the rate at which Io loses volatiles, by a variety of processes, to the surrounding magnetosphere, for the case of both the current, SO2-dominated atmosphere and hypothetical paleoatmospheres in which such other gases as N2 may have been the dominant constituent. Among the mechanisms making significant contributions to the prodigious rate at which Io is losing volatiles are: the interaction of the magnetospheric plasma with volcanic plume particles and the background atmosphere, the sputtering of ices on the surface, if the nightside atmospheric pressure is low enough and Jeans' escape of O as a dissociation product of SO2 gas. It is also argued that in the case of paleoatmospheres only the first two alternatives would have been possible and, nevertheless, insufficient to account for N2 loss over the life of the satellite.

Pollack, J.B.; Witteborn, F.C.

1980-01-01

198

Chirospecific analysis of plant volatiles  

NASA Astrophysics Data System (ADS)

Characteristic features of the analysis of plant volatiles by enantioselective gas (gas-liquid) chromatography and gas chromatography/mass spectrometry are discussed. The most recent advances in the design of enantioselective stationary phases are surveyed. Examples of the preparation of the most efficient phases based on modified cyclodextrins are given. Current knowledge on the successful analytical resolution of different types of plant volatiles (aliphatic and aromatic compounds and mono-, sesqui- and diterpene derivatives) into optical antipodes is systematically described. Chiral stationary phases used for these purposes, temperature conditions and enantiomer separation factors are summarised. Examples of the enantiomeric resolution of fragrance compounds and components of plant extracts, wines and essential oils are given.

Tkachev, A. V.

2007-10-01

199

Sorption and permeation of low molecular weight volatile compounds in polypropylene  

E-print Network

SORPTION AND PERMEATION OP LOW MOLECULAR WEIGHT VOLATILE COMPOUNDS IN POLYPROPYLENE A Thesis by ANTONIO RAMIRO SANTIAGO VIDAL JUNIOR Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment... of the requirements for the degree of MASTER OF SCIENCE August 1991 Major Subject: Mechanical Engineering SORPTION AND PERMEATION OF LOW MOLECULAR WEIGHT VOLATILE COMPOUNDS IN POLYPROPYLENE A Thesis by ANTONIO RAMIRO SANTIAGO VIDAL JUNIOR Approved...

Vidal, Antonio Ramiro Santiago

2012-06-07

200

???????????????????????????????????????????????????????????????????????????????????? Composition and antituberculosis activity of the volatile oil of Heliotropium indicum Linn  

Microsoft Academic Search

The volatile oil from the aerial parts of H. indicum was isolated by hydrodistillation and analyzed by a combination of gas chromatography (GC-FID) and gas chromatography-mass spectrometry (GC-MS). The essential oil was obtained in 0.004% yield as a light brown liquid. The major constituents of the volatile oil of H. indicum were phytol (49.1%), 1-dodecanol (6.4%) and ?-linalool (3.0%). In

Theeraphan Machan; John Korth; Boonsom Liawruangrath; Saisunee Liawruangrath; Stephen G. Pyne

201

Ammonia volatilization from surface application of ammonium sulfate to carbonate systems  

E-print Network

AMMONIA VOLATILIZATION FROM SURFACE APPLICATION OF AMMONIUM SULFATE TO CARBONATE SYSTEMS A Thesis by SAM EDWARD FEAGLEY Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement for the degree... of MASTER OF SCIENCE August 1976 Major Subject; Soil Science AMMONIA VOLATILIZATION FROM SURFACE APPLICATIONS OF AMMONIUM SULFATE TO CARBONATE SYSTEMS A Thesis SAM EDWARD FEAGLEY Approved as to style and content by: Chairman of Committee Head of Dep...

Feagley, Sam Edward

2012-06-07

202

Volatile fatty acid fermentation of lime-treated biomass by rumen microorganisms  

E-print Network

VOLATILE FATTY ACID FERMENTATION OF LIME-TREATED BIOMASS BY RUMEN MICROORGANISMS A Thesis by CHARLES ROBERT RAPIER Submitted to the Office of Cnaduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree... of MASTER OF SCIENCE August 1995 Major Subject: Chemical Engineeriug VOLATILE FATTY ACID FERMENTATION OF LIME-TREATED BIOMASS BY RUMEN MICROORGANISMS A Thesis by CHARLES ROBERT RAPIER Submitted to Texas AkM University in partial fultillment...

Rapier, Charles Robert

2012-06-07

203

Escape of volatiles from Venus  

NASA Astrophysics Data System (ADS)

A model for describing the loss of atmosphere in Venus in the geologic time is presented. The amount of volatiles degassed from Venus in 4.6 Ga is in the order of 286.9 Terrestrial Atmospheric Masses (TAM) (1 TAM = 5.28x1018 kg). If the drag of the solar wind acted since the birth of Venus, 4.6 Ga ago, a minimum limit of the amount of atmosphere lost by the planet is 6.76 TAM. The current atmosphere of Venus has 88.44 TAM of mass. The sum of the lost and the current atmosphere is 95.2 TAM. This result is 191.7 TAM smaller than the estimation of the mass degassed in all the history of Venus. Then we have a deficit of 191.7 TAM of volatiles on Venus. It is well known that the surface of Venus is geologically young (? 500 Ma) In all this period the model predicts that Venus lost, by the solar wind, only 0.08 TAM of atmosphere. From this we can assume that the deficit of volatiles is due to events that occur before that time or perhaps at that time. It is possible to speculate that the resurfacing of Venus, the massive loss of volatiles, and a change from prograde to retrograde rotation of the planet occur at the same time and could be produced by a gigantic impact with a planetary-size body. In this catastrophic event the angular momentum of the planet could change from the original (possibly prograde) to the current one, all the surface of Venus could be melt producing a resurfacing and the water and part of the CO2 in the atmosphere could be ejected to space.

Durand-Manterola, H. J.

204

Photodegradation and volatility of pesticides  

Microsoft Academic Search

Background and Objectives  Among the factors affecting the environmental fate of surface-applied pesticides several biological as well as abiotic factors,\\u000a such as volatilization and photochemical transformations are of particular interest. Whereas reliable measurement methods\\u000a and models for estimating direct photodegradation are already available for the compartments of water and atmosphere and individual\\u000a subprocesses have already been described in detail, there is

Thomas Kromer; Holger Ophoff; Andreas Stork; Fritz Fiihr

2004-01-01

205

Streptopyridines, volatile pyridine alkaloids produced by Streptomyces sp. FORM5  

PubMed Central

Summary Streptomyces sp. FORM5 is a bacterium that is known to produce the antibiotic streptazolin and related compounds. We investigated the strain for the production of volatiles using the CLSA (closed-loop stripping analysis) method. Liquid and agar plate cultures revealed the formation of new 2-alkylpyridines (streptopyridines), structurally closely related to the already known 2-pentadienylpiperidines. The structures of the streptopyridines A to E were confirmed by total synthesis. The analysis of the liquid phase by solvent extraction or extraction with an Oasis adsorbent showed that streptazolin and 2-pentadienylpiperidine are the major compounds, while the streptopyridines are only minor components. In the gas phase, only the streptopyridines could be detected. Therefore, an orthogonal set of analysis is needed to assess the metabolic profile of bacteria, because volatile compounds are obviously overlooked by traditional analytical methods. The streptopyridines are strain specific volatiles that are accompanied by a broad range of headspace constituents that occur in many actinomycetes. Volatiles might be of ecological importance for the producing organism, and, as biosynthetic intermediates or shunt products, they can be useful as indicators of antibiotic production in a bacterium. PMID:24991297

Groenhagen, Ulrike; Maczka, Michael; Dickschat, Jeroen S

2014-01-01

206

Volatiles in Earths interior (Invited)  

NASA Astrophysics Data System (ADS)

Water is certainly the most important volatile. Recycling of water into the mantle occurs in subduction zones where water also triggers melting in the mantle wedge above the subducted slab. However, both the flux of water into the zone of melting as well as the composition of the fluids are poorly constrained. Moreover, it is uncertain whether fluids percolate through the mantle wedge primarily by channelized flow or by pervasive flow, with major implications for the relative contributions of subducted slab and the mantle wedge to the trace element budget of island arc volcanics. To constrain the composition and the flux of fluids in subduction zones, we have measured the solubilities of UO2, ThSiO4, MoOx and WOx in fluids of variable salinity and over a range of oxygen fugacities (Bali et al., in prep). In separate sets of experiments, we measured the solubility of U, Th, Mo, and W in mantle minerals coexisting with the corresponding phases in order to determine fluid/mineral partition coefficients. Our data show that the U/Th ratio in calcalkaline volcanics is a sensitive indicator of redox state and salinity and observed enrichments of U over Th require transport by oxidizing and moderately saline fluids. W, on the other hand, is always very incompatible in mantle minerals and strongly partitioned into aqueous fluids, irrespective of oxidation state and salinity. W contents in magmas can therefore be used to constrain the amount of fluids involved in melting. To distinguish between channelized and pervasive flow in subduction zones, we also looked at the partitioning of halogens, particularly chlorine between aqueous fluids and mantle minerals (Bernini et al., in prep.). Chlorine is highly incompatible in upper mantle minerals, with concentrations below 1 ppm in mantle minerals in equilibrium with fluids containing several wt. % of NaCl. Since water solubility in mantle minerals is much higher than Cl solubility, fluids percolating through the mantle will loose much more water than chlorine and therefore become concentrated. From available data on the salinities of fluids released from the slab and the Cl/H2O ratio in primitive melt inclusions from arc volcanoes, we can estimate that the ratio of rock to fluid that must have reached chemical equilibrium must exceed 1000, implying that fluids percolate by pervasive flow through the mantle wedge. The relative abundance of noble gases on Earth, particularly the depletion of Xe relative to Ar must be due to some process occurring very early in Earth history. We show new experimental results (Shcheka & Keppler, in prep.) that demonstrate that argon is highly compatible in MgSiO3 perowskite, with concentrations reaching more than 1 wt. % at 24 GPa and 1600 C, while xenon solubility is negligible. We therefore suggest that during the crystallization of a magma ocean, argon was preferentially incorporated into perovskite, while most noble gases from the atmosphere were lost to space. Mantle convection later released argon, but not xenon from the deep mantle to the surface and therefore produced the high Ar/Xe ratio in Earths atmosphere. The depletion of Xe relative to Ar is therefore likely to be characteristic for a planet that underwent fractionation of silicate perovskite from a magma ocean.

Keppler, H.

2010-12-01

207

Detection of variable groundwater inflow in rivers with geochemical tracers: Using major ion chemistry and radiochemistry to evaluate radon 222Rn as possible tracer, an example from the Avon and Mitchell rivers, southeast Australia  

NASA Astrophysics Data System (ADS)

Surface water-groundwater interactions are an important part of the hydrological cycle from ecological and resource perspectives. The dynamics have implications for ecosystems, pollutant transport, and the quality and quantity of water supply for domestic use, agriculture and recreational purposes. Chemical tracers are a valuable tool for understanding the interaction of rivers and the surrounding groundwater. The Gippsland Basin is a significant agricultural area in Southeast Australia. Increasing population has resulted in increased demand of water resources for domestic and agricultural supply. Despite the fact that the Gippsland area receives substantial rainfall, irrigation is still necessary to maintain agricultural production during summer and drier years. The used water resources encompass mostly shallow groundwater and surface water (reservoirs and streams). The effect on the environment range from rising water levels and soil salinisation in the case of irrigation and falling water levels with subsequent necrotization of the vegetation and land subsidence in the case of communal and industrial water extraction. While the surface water components of the hydrological cycle are relatively well understood, groundwater has often been neglected. In particular, constraining the interaction between surface water and groundwater is required for sustainable water management. Gaining and loosing conditions in streams are subject to high temporal and spatial variability and hence, influence the amount of water accessible for agricultural purposes. Following a general assumption recharge to the aquifer occurs during the winter and spring month whereas the river receives water from the aquifer mainly during low flow (base flow) conditions in summer and autumn on a larger scale. Spatial variation, however, are a function of the hydraulic conductivity of the riverbed and the head differences between the aquifer and the river along the river banks. Infiltration and exfiltration rates from changing water levels in the river based on hydraulic models are often underestimated. The hydraulic models do not take into account the complexity of the system and are purely based on discharge figures. Radon (222Rn), stable isotopes and major ion chemistry were used to locate groundwater inputs to the Mitchell and Avon rivers. While stable isotopes and major ion chemistry are useful tracers to determine long-term variability, radon can be used to detect very localised groundwater discharge. Using hydrogeochemistry to locate and quantify groundwater discharge to rivers allows a more accurate assumption on the dynamics of the interaction between surface water and groundwater in the Gippsland area. Radon has been used in similar applications elsewhere. Input parameters for mass balance equations, however, were often approximated and averaged. Radioisotope concentrations in groundwater has been assessed from 20 bores and 5 soil profiles to deliver a more confidential groundwater input water radon concentration by assessing spatial variability and emanation potential of the above-mentioned elements.

Hofmann, H.; Cartwright, I.

2010-12-01

208

Stochastic volatility models and Kelvin waves  

NASA Astrophysics Data System (ADS)

We use stochastic volatility models to describe the evolution of an asset price, its instantaneous volatility and its realized volatility. In particular, we concentrate on the Stein and Stein model (SSM) (1991) for the stochastic asset volatility and the Heston model (HM) (1993) for the stochastic asset variance. By construction, the volatility is not sign definite in SSM and is non-negative in HM. It is well known that both models produce closed-form expressions for the prices of vanilla option via the Lewis-Lipton formula. However, the numerical pricing of exotic options by means of the finite difference and Monte Carlo methods is much more complex for HM than for SSM. Until now, this complexity was considered to be an acceptable price to pay for ensuring that the asset volatility is non-negative. We argue that having negative stochastic volatility is a psychological rather than financial or mathematical problem, and advocate using SSM rather than HM in most applications. We extend SSM by adding volatility jumps and obtain a closed-form expression for the density of the asset price and its realized volatility. We also show that the current method of choice for solving pricing problems with stochastic volatility (via the affine ansatz for the Fourier-transformed density function) can be traced back to the Kelvin method designed in the 19th century for studying wave motion problems arising in fluid dynamics.

Lipton, Alex; Sepp, Artur

2008-08-01

209

NATURAL EMISSIONS OF NON-METHANE VOLATILE ORGANIC COMPOUNDS, CARBON MONOXIDE, AND OXIDES OF NITROGEN FROM NORTH AMERICA. (R825259)  

EPA Science Inventory

Abstract The magnitudes, distributions, controlling processes and uncertainties associated with North American natural emissions of oxidant precursors are reviewed. Natural emissions are responsible for a major portion of the compounds, including non-methane volatile o...

210

NATURAL EMISSIONS OF NON-METHANE VOLATILE ORGANIC COMPOUNDS, CARBON MONOXIDE, AND OXIDES OF NITROGEN FROM NORTH AMERICA  

EPA Science Inventory

The magnitudes, distributions, controlling processes and uncertainties associated with North American natural emissions of oxidant precursors are reviewed. Natural emissions are repsonsible for a major portion of the compounds, including non-methane volatile organic compounds (N...

211

AMBIENT LEVEL VOLATILE ORGANIC COMPOUND (VOC) MONITORING USING SOLID ADSORBANTS - RECENT U.S. EPA STUDIES  

EPA Science Inventory

Ambient air spiked with 1-10 ppbv concentrations of 41 toxic volatile organic compounds (VOCs) listed in U.S. Environmental Protection Agency (EPA) Compendium Method TO-14A was monitored using solid sorbents for sample collection and a Varian Saturn 2000 ion trap mass spectrome...

212

PSYCHOLOGY MAJORS --1 PSYCHOLOGY MAJORS --2  

E-print Network

and the world: Developmental Psychology, Social Psy- chology, Cognitive Psychology, Theories of PersonalityPSYCHOLOGY MAJORS -- 1 #12;PSYCHOLOGY MAJORS -- 2 Handbook for Undergraduate Psychology Majors......................................................................................................................................2 A. Psychology Program Goals and Purpose B. Declaration of Major C. History of Marquette University

Sanders, Matthew

213

Volatile organic compound emissions from Siberian larch  

NASA Astrophysics Data System (ADS)

We determined hourly emissions of isoprene, monoterpenes and sesquiterpenes from Siberian larch, one of the major tree species in Siberian forests. Summer volatile organic compounds (VOCs) emission from Siberian larch consisted mainly of monoterpenes (about 90%). The monoterpene emission spectrum remained constant during the measurement period, almost half was sabinene and other major monoterpenes were ?3-carene, ?- and ?-pinene. During spring and summer, about 10% of the VOCs were sesquiterpenes, mainly ?-farnesene. The sesquiterpene emissions declined to 3% in the fall. Isoprene, 2-methyl-3-buten-2-ol (MBO) and 1,8-cineole contributed to less than 3% of the VOC emission during the whole period. The diurnal variation of the emissions could be explained using a temperature-dependent parameterization. Emission potentials normalized to 30 °C were 5.2-21 ?g g dw-1 h -1 (using ?-value of 0.09 °C -1) for monoterpenes and 0.4-1.8 ?g g dw-1 h -1 (using ?-value of 0.143 °C -1, mean of determined values) for sesquiterpenes. Normalized monoterpene emission potentials were highest in late summer and elevated again in late fall. Sesquiterpene emission potentials were also highest in late summer, but decreased towards fall.

Ruuskanen, T. M.; Hakola, H.; Kajos, M. K.; Hellén, H.; Tarvainen, V.; Rinne, J.

214

Production of volatile organic compounds by mycobacteria.  

PubMed

The need for improved rapid diagnostic tests for tuberculosis disease has prompted interest in the volatile organic compounds (VOCs) emitted by Mycobacterium tuberculosis complex bacteria. We have investigated VOCs emitted by Mycobacterium bovis BCG grown on Lowenstein-Jensen media using selected ion flow tube mass spectrometry and thermal desorption-gas chromatography-mass spectrometry. Compounds observed included dimethyl sulphide, 3-methyl-1-butanol, 2-methyl-1-propanol, butanone, 2-methyl-1-butanol, methyl 2-methylbutanoate, 2-phenylethanol and hydrogen sulphide. Changes in levels of acetaldehyde, methanol and ammonia were also observed. The compounds identified are not unique to M. bovis BCG, and further studies are needed to validate their diagnostic value. Investigations using an ultra-rapid gas chromatograph with a surface acoustic wave sensor (zNose) demonstrated the presence of 2-phenylethanol (PEA) in the headspace of cultures of M. bovis BCG and Mycobacterium smegmatis, when grown on Lowenstein-Jensen supplemented with glycerol. PEA is a reversible inhibitor of DNA synthesis. It is used during selective isolation of gram-positive bacteria and may also be used to inhibit mycobacterial growth. PEA production was observed to be dependent on growth of mycobacteria. Further study is required to elucidate the metabolic pathways involved and assess whether this compound is produced during in vivo growth of mycobacteria. PMID:22224870

McNerney, Ruth; Mallard, Kim; Okolo, Phyllis Ifeoma; Turner, Claire

2012-03-01

215

Localization of volatile isotopes on a cryotrap  

NASA Astrophysics Data System (ADS)

Neutron-induced fission of uranium allows for the production of high-intensity neutron-rich radioactive ion beams. However, also large quantities of unwanted volatile radioactive species are produced that have to be hindered from contaminating the beamline and vacuum system of the facility. In the framework of radioprotection studies within the MAFF project at the FRM II in Garching with 10 14 fission events/s [D. Habs et al., The Munich accelerator for fission fragments MAFF, Nucl. Instr. and Meth. B 204 (2003) 739], the performance of a cryotrap system has been studied, designed to localize gaseous radioactivity close to its origin. These studies provide important radioprotection information for the planned EURISOL facility with 10 15 fission events/s. Design considerations of a compact cryotrap operated with cold helium gas at a saturation temperature around 18 K will be presented. Activity distribution calculations of the fission source, the cryotrap and the subsequent vacuum system result in a prediction of the retention capability of the cryotrap system of 99.98%. These design calculations have been experimentally verified with three cryotrap prototypes differing in cold surface area as well as in their internal helium gas flow characteristics. Retention capabilities have been measured with and without passive shielding of the external thermal load (300 K) using different tracer gases and an inclusive pressure-related diagnostics as well as mass-spectroscopic measurements.

Thirolf, P. G.; Gross, M.; Habs, D.; Kohlhund, A.; Nebel, F.; Neumayr, J. B.; Stoepler, R.; Szerypo, J.

2008-10-01

216

Floral volatiles: from biosynthesis to function.  

PubMed

Floral volatiles have attracted humans' attention since antiquity and have since then permeated many aspects of our lives. Indeed, they are heavily used in perfumes, cosmetics, flavourings and medicinal applications. However, their primary function is to mediate ecological interactions between flowers and a diverse array of visitors, including pollinators, florivores and pathogens. As such, they ultimately ensure the plants' reproductive and evolutionary success. To date, over 1700 floral volatile organic compounds (VOCs) have been identified. Interestingly, they are derived from only a few biochemical networks, which include the terpenoid, phenylpropanoid/benzenoid and fatty acid biosynthetic pathways. These pathways are intricately regulated by endogenous and external factors to enable spatially and temporally controlled emission of floral volatiles, thereby fine-tuning the ecological interactions facilitated by floral volatiles. In this review, we will focus on describing the biosynthetic pathways leading to floral VOCs, the regulation of floral volatile emission, as well as biological functions of emitted volatiles. PMID:24588567

Muhlemann, Joëlle K; Klempien, Antje; Dudareva, Natalia

2014-08-01

217

Fatty Acid Composition and Volatile Constituents of Protaetia brevitarsis Larvae  

PubMed Central

A total of 48 different volatile oils were identified form P. brevitarsis larvae by gas chromatography/mass spectrometry (GC/MS). Acids (48.67%) were detected as the major group in P. brevitarsis larvae comprising the largest proportion of the volatile compounds, followed by esters (19.84%), hydrocarbons (18.90%), alcohols (8.37%), miscellaneous (1.71%), aldehydes (1.35%) and terpenes (1.16%). The major volatile constituents were 9-hexadecenoic acid (16.75%), 6-octadecenoic acid (14.88%) and n-hexadecanoic acid (11.06%). The composition of fatty acid was also determined by GC analysis and 16 fatty acids were identified. The predominant fatty acids were oleic acid (C18:1, 64.24%) followed by palmitic acid (C16:0, 15.89%), palmitoleic acid (C16:1, 10.43%) and linoleic acid (C18:2, 4.69%) constituting more than 95% of total fatty acids. The distinguished characteristic of the fatty acid profile of P. brevitarsis larvae was the high proportion of unsaturated fatty acid (80.54% of total fatty acids) versus saturated fatty acids (19.46% of total fatty acids). Furthermore, small but significant amounts of linoleic, linolenic and ?-linolenic acids bestow P. brevitarsis larvae with considerable nutritional value. The novel findings of the present study provide a scientific basis for the comprehensive utilization of the insect as a nutritionally promising food source and a possibility for more effective utilization. PMID:24471125

Yeo, Hyelim; Youn, Kumju; Kim, Minji; Yun, Eun-Young; Hwang, Jae-Sam; Jeong, Woo-Sik; Jun, Mira

2013-01-01

218

Bacterial volatiles and their action potential  

Microsoft Academic Search

During the past few years, an increasing awareness concerning the emission of an unexpected high number of bacterial volatiles\\u000a has been registered. Humans sense, intensively and continuously, microbial volatiles that are released during food transformation\\u000a and fermentation, e.g., the aroma of wine and cheese. Recent investigations have clearly demonstrated that bacteria also employ\\u000a their volatiles during interactions with other organisms

Marco Kai; Maria Haustein; Francia Molina; Anja Petri; Birte Scholz; Birgit Piechulla

2009-01-01

219

Predicting stock market volatility: A new measure  

Microsoft Academic Search

INTRODUCTIONThe CBOE Market Volatility Index (VIX) is an average of S&P 100option (OEX) implied volatilities. As such, it represents a market-consensus estimate of future stock market volatility. 1 The computationand dissemination of VIX on a real-time basis offers practitioners andacademics an important new source of information. Practitioners, forThis research was supported by the Futures and Options Research Center at the

Jeff Fleming; Barbara Ostdiek; Robert E. Whaley

1995-01-01

220

Silicon Nanowires for Non-Volatile Memory  

E-print Network

Silicon Nanowires for Non-Volatile Memory P R O J E C T L E A D E R : Curt A. Richter (NIST) C O L approaches for silicon nanowire non-volatile memory. K E Y A C C O M P L I S H M E N T S Fabricated novel non-volatile memory cells with silicon nanowire channels and Al2 O3 /HfO2 /SiO2 gate dielectric storage stacks

221

Flavour compounds in tomato fruits: identification of loci and potential pathways affecting volatile composition  

PubMed Central

The unique flavour of a tomato fruit is the sum of a complex interaction among sugars, acids, and a large set of volatile compounds. While it is generally acknowledged that the flavour of commercially produced tomatoes is inferior, the biochemical and genetic complexity of the trait has made breeding for improved flavour extremely difficult. The volatiles, in particular, present a major challenge for flavour improvement, being generated from a diverse set of lipid, amino acid, and carotenoid precursors. Very few genes controlling their biosynthesis have been identified. New quantitative trait loci (QTLs) that affect the volatile emissions of red-ripe fruits are described here. A population of introgression lines derived from a cross between the cultivated tomato Solanum lycopersicum and its wild relative, S. habrochaites, was characterized over multiple seasons and locations. A total of 30 QTLs affecting the emission of one or more volatiles were mapped. The data from this mapping project, combined with previously collected data on an IL population derived from a cross between S. lycopersicum and S. pennellii populations, were used to construct a correlational database. A metabolite tree derived from these data provides new insights into the pathways for the synthesis of several of these volatiles. One QTL is a novel locus affecting fruit carotenoid content on chromosome 2. Volatile emissions from this and other lines indicate that the linear and cyclic apocarotenoid volatiles are probably derived from separate carotenoid pools. PMID:19088332

Mathieu, Sandrine; Cin, Valeriano Dal; Fei, Zhangjun; Li, Hua; Bliss, Peter; Taylor, Mark G.; Klee, Harry J.; Tieman, Denise M.

2009-01-01

222

Study of the volatile compounds produced by Debaryomyces hansenii NRRL Y-7426 during the fermentation of detoxified concentrated distilled grape marc hemicellulosic hydrolysates.  

PubMed

The volatile compounds produced by Debaryomyces hansenii NRRL Y-7426 during the fermentation of detoxified concentrated distilled grape marc hemicellulosic hydrolysates was analysed by GC-MS. Thirty-five compounds corresponding to ten groups of volatile compounds: terpenes, higher alcohols, C? alcohols, aldehydes, volatile acids, acetates, ethyl esters, volatile phenols, sulphur compounds and hydrocarbons were identified. The supplementation with commercial nutrients increased the concentration of 2-phenylethanol, a commercial flavour and fragrance compound, with a rose-like odour, employed in cosmetics and food industries; and other positive compounds to the aroma such as terpenes and ethyl esters. Non-supplemented media produced the highest content in higher alcohols, volatile acids, sulphur compounds and in the majority of hydrocarbons detected, meanwhile supplementation with vinasses hardly produced volatile compounds. Only four volatile compounds contributed directly to the aroma according to the OAVs values higher than 1. Finally, a PCA analysis allowed accounting for 100 % of the variance. PMID:22806750

Salgado, José Manuel; González-Barreiro, Carmen; Rodríguez-Solana, Raquel; Simal-Gándara, Jesús; Domínguez, José Manuel; Cortés, Sandra

2012-11-01

223

Volatile components of vine leaves from two Portuguese grape varieties (Vitis vinifera L.), Touriga Nacional and Tinta Roriz, analysed by solid-phase microextraction.  

PubMed

The purpose of this work was to study the volatile composition of vine leaves and vine leaf infusion prepared from vine leaves collected at 30 and 60 days after grape harvest of two Vitis vinifera L. species. Eighteen volatile compounds were identified by gas chromatography-mass spectrometry in vine leaves and in vine leaf infusions. It was observed that the volatile compounds present in vine leaves are dependent on the time of harvest, with benzaldehyde being the major volatile present in vine leaves collected at 30 days after harvesting. There are significant differences in the volatile composition of the leaves from the two grape cultivars, especially in the sample collected at 60 days after grape harvest. This is not reflected in the volatile composition of the vine leaf infusion made from this two cultivars, the more important being the harvesting date for the volatile profile of vine leaf infusion than the vine leaves grape cultivar. PMID:25226431

Fernandes, Bruno; Correia, Ana C; Cosme, Fernanda; Nunes, Fernando M; Jordão, António M

2015-01-01

224

Deodorization of garlic breath volatiles by food and food components.  

PubMed

The ability of foods and beverages to reduce allyl methyl disulfide, diallyl disulfide, allyl mercaptan, and allyl methyl sulfide on human breath after consumption of raw garlic was examined. The treatments were consumed immediately following raw garlic consumption for breath measurements, or were blended with garlic prior to headspace measurements. Measurements were done using a selected ion flow tube-mass spectrometer. Chlorophyllin treatment demonstrated no deodorization in comparison to the control. Successful treatments may be due to enzymatic, polyphenolic, or acid deodorization. Enzymatic deodorization involved oxidation of polyphenolic compounds by enzymes, with the oxidized polyphenols causing deodorization. This was the probable mechanism in raw apple, parsley, spinach, and mint treatments. Polyphenolic deodorization involved deodorization by polyphenolic compounds without enzymatic activity. This probably occurred for microwaved apple, green tea, and lemon juice treatments. When pH is below 3.6, the enzyme alliinase is inactivated, which causes a reduction in volatile formation. This was demonstrated in pH-adjusted headspace measurements. However, the mechanism for volatile reduction on human breath (after volatile formation) is unclear, and may have occurred in soft drink and lemon juice breath treatments. Whey protein was not an effective garlic breath deodorant and had no enzymatic activity, polyphenolic compounds, or acidity. Headspace concentrations did not correlate well to breath treatments. PMID:24592995

Munch, Ryan; Barringer, Sheryl A

2014-04-01

225

Low volatile organic compound paints  

SciTech Connect

Increasingly stringent air emission standards in various states has dictated the elimination of engineering finishes which are derived from high volatile organic compound (VOC) paint chemistries. In July 1989, Allied-Signal, Inc., Kansas City Division, Kansas City, Missouri, voluntarily closed its paint facility, due to non-compliance with local air emission standards. The following details the materials selection and evaluations which led to current processing using low VOC paints, which permitted the Allied Signal, Inc., paint facility to achieve compliance and resume operations. 1 tab.

Martinez, F.E.

1991-01-01

226

Volatile halogenated hydrocarbons in foods  

SciTech Connect

Volatile halogenated organic compounds were determined in foods. Statistical treatment of the data for 13 sampled from 20 families living in suburban Tokyo (Saitama prefecture) indicated that the foods were contaminated by water pollution and/or substances introduced by the process of food production. Butter and margarine were contaminated by chlorinated ethylene, ethane, and related compounds released by dry cleaning and other operations. Soybean sprouts and tofu (soybean curd) contained chloroform and related trihalomethanes absorbed during the production process. 27 refs., 6 figs., 5 tabs.

Miyahara, Makoto; Toyoda, Masatake; Saito, Yukio [National Institute of Health Services, Tokyo (Japan)] [and others

1995-02-01

227

Volatile organic compound sensor system  

DOEpatents

Generally, this invention relates to the development of field monitoring methodology for new substances and sensing chemical warfare agents (CWAs) and terrorist substances. It also relates to a portable test kit which may be utilized to measure concentrations of halogenated volatile organic compounds (VOCs) in the field. Specifically it relates to systems for reliably field sensing the potential presence of such items while also distinguishing them from other elements potentially present. It also relates to overall systems and processes for sensing, reacting, and responding to an indicated presence of such substance, including modifications of existing halogenated sensors and arrayed sensing systems and methods.

Schabron, John F. (Laramie, WY); Rovani, Jr., Joseph F. (Laramie, WY); Bomstad, Theresa M. (Waxahachie, TX); Sorini-Wong, Susan S. (Laramie, WY); Wong, Gregory K. (Laramie, WY)

2011-03-01

228

Conference on Deep Earth and Planetary Volatiles  

NASA Technical Reports Server (NTRS)

The following topics are covered in the presented papers: (1) rare gases systematics and mantle structure; (2) volatiles in the earth; (3) impact degassing of water and noble gases from silicates; (4) D/H ratios and H2O contents of mantle-derived amphibole megacrysts; (5) thermochemistry of dense hydrous magnesium silicates; (6) modeling of the effect of water on mantle rheology; (7) noble gas isotopes and halogens in volatile-rich inclusions in diamonds; (8) origin and loss of the volatiles of the terrestrial planets; (9) structure and the stability of hydrous minerals at high pressure; (10) recycling of volatiles at subduction zones and various other topics.

1994-01-01

229

Citrus Leaf Volatiles as Affected by Developmental Stage and Genetic Type  

PubMed Central

Major volatiles from young and mature leaves of different citrus types were analyzed by headspace-solid phase microextraction (HS-SPME)-GC-MS. A total of 123 components were identified form nine citrus cultivars, including nine aldehydes, 19 monoterpene hydrocarbons, 27 oxygenated monoterpenes, 43 sesquiterpene hydrocarbons, eight oxygenated sesquiterpenes, two ketones, six esters and nine miscellaneous. Young leaves produced higher amounts of volatiles than mature leaves in most cultivars. The percentage of aldehyde and monoterpene hydrocarbons increased, whilst oxygenated monoterpenes and sesquiterpenes compounds decreased during leaf development. Linalool was the most abundant compound in young leaves, whereas limonene was the chief component in mature ones. Notably, linalool content decreased, while limonene increased, during leaf development in most cultivars. Leaf volatiles were also affected by genetic types. A most abundant volatile in one or several genotypes can be absent in another one(s), such as limonene in young leaves of lemon vs. Satsuma mandarin and ?-terpinene in mature leaves of three genotypes vs. the other four. Compositional data was subjected to multivariate statistical analysis, and variations in leaf volatiles were identified and clustered into six groups. This research determining the relationship between production of major volatiles from different citrus varieties and leaf stages could be of use for industrial and culinary purposes. PMID:23994837

Azam, Muhammad; Jiang, Qian; Zhang, Bo; Xu, Changjie; Chen, Kunsong

2013-01-01

230

Econometric analysis of realized volatility and its use in estimating stochastic volatility models  

Microsoft Academic Search

The availability of intraday data on the prices of speculative assets means that we can use quadratic variation-like measures of activity in financial markets, called realized volatility, to study the stochastic properties of returns. Here, under the assumption of a rather general stochastic volatility model, we derive the moments and the asymptotic distribution of the realized volatility error-the difference between

Ole E. Barndorff-Nielsen; Neil Shephard

2002-01-01

231

Birds exploit herbivore-induced plant volatiles to locate herbivorous prey.  

PubMed

Arthropod herbivory induces plant volatiles that can be used by natural enemies of the herbivores to find their prey. This has been studied mainly for arthropods that prey upon or parasitise herbivorous arthropods but rarely for insectivorous birds, one of the main groups of predators of herbivorous insects such as lepidopteran larvae. Here, we show that great tits (Parus major) discriminate between caterpillar-infested and uninfested trees. Birds were attracted to infested trees, even when they could not see the larvae or their feeding damage. We furthermore show that infested and uninfested trees differ in volatile emissions and visual characteristics. Finally, we show, for the first time, that birds smell which tree is infested with their prey based on differences in volatile profiles emitted by infested and uninfested trees. Volatiles emitted by plants in response to herbivory by lepidopteran larvae thus not only attract predatory insects but also vertebrate predators. PMID:24103093

Amo, Luisa; Jansen, Jeroen J; van Dam, Nicole M; Dicke, Marcel; Visser, Marcel E

2013-11-01

232

Principal volatile odorants and dynamics of their formation during the production of May Bryndza cheese.  

PubMed

Volatile aroma compounds were investigated along the production of May Bryndza cheese, a traditional Slovakian cheese produced from raw ewes' milk. Solid phase microextraction was used to isolate the volatile fractions, which were subsequently analysed by gas chromatography-olfactometry and gas chromatography-mass spectrometry. Twenty-seven key odorants were found and described in the intermediate product, ewes' curd ripened for 0, 1, 2, 4, and 8days, or in the final product. A major overall increase in the number of aroma-active volatile compounds and in their odour intensity or concentration took place during the first day of ripening of the ewes' curd, and the odour gradually culminated at the end of ripening. During the final technological step of Bryndza cheese production, when the ewes' curd ripened for 10days is decrusted, pressed and milled with NaCl solution, 8 aroma-active volatile compounds disappeared. PMID:24360454

Sádecká, Jana; Kolek, Emil; Pangallo, Domenico; Valík, Lubomír; Kuchta, Tomáš

2014-05-01

233

Antimicrobial activity of volatile components and various extracts of the red alga Jania rubens.  

PubMed

The methanol, dichloromethane, hexane, chloroform and volatile oil extracts of the red alga Jania rubens were tested in vitro for their antimicrobial activity (five Gram-positive, four Gram-negative bacteria and Candida albicans ATCC 10239). GC-MS analysis of the volatile components of J. rubens identified 40 compounds which constituted 77.53% of the total. The volatile components of J. rubens consisted of n-docosane (6.35%), n-eicosane (5.77%) and n-tetratriacontane (5.58%) as major components. The methanol and chloroform extracts (4 mg/disc) showed more potent antimicrobial activity than the hexane and dichloromethane extracts and the volatile oil of J. rubens. PMID:17128433

Karabay-Yavasoglu, N Ulku; Sukatar, Atakan; Ozdemir, Guven; Horzum, Zerrin

2007-02-01

234

Non-volatile memory based on transition metal perovskite oxide resistance switching  

NASA Astrophysics Data System (ADS)

Driven by the non-volatile memory market looking for new advanced materials, this dissertation focuses on the study of non-volatile resistive random access memory (RRAM) based on transition metal perovskite oxides. Pr0.7Ca0.3MnO3 (PCMO), one of the representative materials in this family, has demonstrated a large range of resistance change when short electrical pulses with different polarity are applied. Such electrical-pulse-induced resistance (EPIR), with attractive features such as fast response, low power, high-density and non-volatility, makes PCMO and related materials promising candidates for non-volatile RRAM application. The objective of this work is to investigate, optimize and understand the properties of this universal EPIR behavior in transition metal perovskite oxide, represented by PCMO thin film devices. The research work includes fabrication of PCMO thin film devices, characterization of these EPIR devices as non-volatile memories, and investigation of their resistive switching mechanisms. The functionality of this perovskite oxide RRAM, including pulse magnitude/width dependence, power consumption, retention, endurance and radiation-hardness has been investigated. By studying the "shuttle tail" in hysteresis switching loops of oxygen deficient devices, a diffusion model with oxygen ions/vacancies as active agents at the metal/oxide interface is proposed for the non-volatile resistance switching effect in transition metal perovskite oxide thin films. The change of EPIR switching behavior after oxygen/argon ion implantation also shows experiment support for the proposed model. Furthermore, the universality, scalability and comparison with other non-volatile memories are discussed for future application.

Nian, Yibo

235

Non-volatile, solid state bistable electrical switch  

NASA Technical Reports Server (NTRS)

A bistable switching element is made of a material whose electrical resistance reversibly decreases in response to intercalation by positive ions. Flow of positive ions between the bistable switching element and a positive ion source is controlled by means of an electrical potential applied across a thermal switching element. The material of the thermal switching element generates heat in response to electrical current flow therethrough, which in turn causes the material to undergo a thermal phase transition from a high electrical resistance state to a low electrical resistance state as the temperature increases above a predetermined value. Application of the electrical potential in one direction renders the thermal switching element conductive to pass electron current out of the ion source. This causes positive ions to flow from the source into the bistable switching element and intercalate the same to produce a non-volatile, low resistance logic state. Application of the electrical potential in the opposite direction causes reverse current flow which de-intercalates the bistable logic switching element and produces a high resistance logic state.

Williams, Roger M. (inventor)

1994-01-01

236

Volatile exchange between undamaged plants - a new mechanism affecting insect orientation in intercropping.  

PubMed

Changes in plant volatile emission can be induced by exposure to volatiles from neighbouring insect-attacked plants. However, plants are also exposed to volatiles from unattacked neighbours, and the consequences of this have not been explored. We investigated whether volatile exchange between undamaged plants affects volatile emission and plant-insect interaction. Consistently greater quantities of two terpenoids were found in the headspace of potato previously exposed to volatiles from undamaged onion plants identified by mass spectrometry. Using live plants and synthetic blends mimicking exposed and unexposed potato, we tested the olfactory response of winged aphids, Myzus persicae. The altered potato volatile profile deterred aphids in laboratory experiments. Further, we show that growing potato together with onion in the field reduces the abundance of winged, host-seeking aphids. Our study broadens the ecological significance of the phenomenon; volatiles carry not only information on whether or not neighbouring plants are under attack, but also information on the emitter plants themselves. In this way responding plants could obtain information on whether the neighbouring plant is a competitive threat and can accordingly adjust their growth towards it. We interpret this as a response in the process of adaptation towards neighbouring plants. Furthermore, these physiological changes in the responding plants have significant ecological impact, as behaviour of aphids was affected. Since herbivore host plants are potentially under constant exposure to these volatiles, our study has major implications for the understanding of how mechanisms within plant communities affect insects. This knowledge could be used to improve plant protection and increase scientific understanding of communication between plants and its impact on other organisms. PMID:23922710

Ninkovic, Velemir; Dahlin, Iris; Vucetic, Andja; Petrovic-Obradovic, Olivera; Glinwood, Robert; Webster, Ben

2013-01-01

237

Volatile Exchange between Undamaged Plants - a New Mechanism Affecting Insect Orientation in Intercropping  

PubMed Central

Changes in plant volatile emission can be induced by exposure to volatiles from neighbouring insect-attacked plants. However, plants are also exposed to volatiles from unattacked neighbours, and the consequences of this have not been explored. We investigated whether volatile exchange between undamaged plants affects volatile emission and plant-insect interaction. Consistently greater quantities of two terpenoids were found in the headspace of potato previously exposed to volatiles from undamaged onion plants identified by mass spectrometry. Using live plants and synthetic blends mimicking exposed and unexposed potato, we tested the olfactory response of winged aphids, Myzus persicae. The altered potato volatile profile deterred aphids in laboratory experiments. Further, we show that growing potato together with onion in the field reduces the abundance of winged, host-seeking aphids. Our study broadens the ecological significance of the phenomenon; volatiles carry not only information on whether or not neighbouring plants are under attack, but also information on the emitter plants themselves. In this way responding plants could obtain information on whether the neighbouring plant is a competitive threat and can accordingly adjust their growth towards it. We interpret this as a response in the process of adaptation towards neighbouring plants. Furthermore, these physiological changes in the responding plants have significant ecological impact, as behaviour of aphids was affected. Since herbivore host plants are potentially under constant exposure to these volatiles, our study has major implications for the understanding of how mechanisms within plant communities affect insects. This knowledge could be used to improve plant protection and increase scientific understanding of communication between plants and its impact on other organisms. PMID:23922710

Ninkovic, Velemir; Dahlin, Iris; Vucetic, Andja; Petrovic-Obradovic, Olivera; Glinwood, Robert; Webster, Ben

2013-01-01

238

IN-HOUSE REFORMULATION AND EVALUATION OF MAJOR MANUFACTURER'S VEHICLE REFINISHING COATINGS  

EPA Science Inventory

The goal is to develop high quality vehicle refinishing paint formulations that contain much less toxi and volatile solvents than the major manufacturer's Federal compliant and California complaint coatings. The reformulated coatings being developed will maintain or improve upo...

239

Volatile fingerprints of seeds of four species indicate the involvement of alcoholic fermentation, lipid peroxidation, and Maillard reactions in seed deterioration during ageing and desiccation stress.  

PubMed

The volatile compounds released by orthodox (desiccation-tolerant) seeds during ageing can be analysed using gas chromatography-mass spectrometry (GC-MS). Comparison of three legume species (Pisum sativum, Lathyrus pratensis, and Cytisus scoparius) during artificial ageing at 60% relative humidity and 50 °C revealed variation in the seed volatile fingerprint between species, although in all species the overall volatile concentration increased with storage period, and changes could be detected prior to the onset of viability loss. The volatile compounds are proposed to derive from three main sources: alcoholic fermentation, lipid peroxidation, and Maillard reactions. Lipid peroxidation was confirmed in P. sativum seeds through analysis of malondialdehyde and 4-hydroxynonenal. Volatile production by ageing orthodox seeds was compared with that of recalcitrant (desiccation-sensitive) seeds of Quercus robur during desiccation. Many of the volatiles were common to both ageing orthodox seeds and desiccating recalcitrant seeds, with alcoholic fermentation forming the major source of volatiles. Finally, comparison was made between two methods of analysis; the first used a Tenax adsorbent to trap volatiles, whilst the second used solid phase microextraction to extract volatiles from the headspace of vials containing powdered seeds. Solid phase microextraction was found to be more sensitive, detecting a far greater number of compounds. Seed volatile analysis provides a non-invasive means of characterizing the processes involved in seed deterioration, and potentially identifying volatile marker compounds for the diagnosis of seed viability loss. PMID:23175670

Colville, Louise; Bradley, Emma L; Lloyd, Antony S; Pritchard, Hugh W; Castle, Laurence; Kranner, Ilse

2012-11-01

240

Volatile fingerprints of seeds of four species indicate the involvement of alcoholic fermentation, lipid peroxidation, and Maillard reactions in seed deterioration during ageing and desiccation stress  

PubMed Central

The volatile compounds released by orthodox (desiccation-tolerant) seeds during ageing can be analysed using gas chromatography–mass spectrometry (GC-MS). Comparison of three legume species (Pisum sativum, Lathyrus pratensis, and Cytisus scoparius) during artificial ageing at 60% relative humidity and 50 °C revealed variation in the seed volatile fingerprint between species, although in all species the overall volatile concentration increased with storage period, and changes could be detected prior to the onset of viability loss. The volatile compounds are proposed to derive from three main sources: alcoholic fermentation, lipid peroxidation, and Maillard reactions. Lipid peroxidation was confirmed in P. sativum seeds through analysis of malondialdehyde and 4-hydroxynonenal. Volatile production by ageing orthodox seeds was compared with that of recalcitrant (desiccation-sensitive) seeds of Quercus robur during desiccation. Many of the volatiles were common to both ageing orthodox seeds and desiccating recalcitrant seeds, with alcoholic fermentation forming the major source of volatiles. Finally, comparison was made between two methods of analysis; the first used a Tenax adsorbent to trap volatiles, whilst the second used solid phase microextraction to extract volatiles from the headspace of vials containing powdered seeds. Solid phase microextraction was found to be more sensitive, detecting a far greater number of compounds. Seed volatile analysis provides a non-invasive means of characterizing the processes involved in seed deterioration, and potentially identifying volatile marker compounds for the diagnosis of seed viability loss. PMID:23175670

Colville, Louise

2012-01-01

241

Belief biases and volatility of assets  

NASA Astrophysics Data System (ADS)

Based on an overlapping generation model, this paper introduces the noise traders with belief biases and rational traders. With an equilibrium analysis, this paper examines the volatility of risky asset. The results show that the belief biases, the probability of economy state, and the domain capability are all the factors that have effects on the volatility of the market.

Lei-Sun, Wen-Zou, Hui

2014-10-01

242

Neonatal withdrawal from maternal volatile substance abuse  

Microsoft Academic Search

AIM: To determine whether neonates born to mothers who are volatile substance abusers are at risk for an abstinence syndrome. METHODS: A consecutive sample of infants born to volatile substance abusing mothers was studied over four years, in a university affiliated medical centre with a variable mix of primary, secondary, and tertiary care patients. Infants were clinically scored with the

M. Tenenbein; O. G. Casiro; M. M. Seshia; V. D. Debooy

1996-01-01

243

FOREIGN DIRECT INVESTMENT AND EXCHANGE RATE VOLATILITY  

Microsoft Academic Search

The objective of this paper is to empirically investigate the relationship between real exchange rate volatility and FDI. While the dominant approach from the policy perspective is that exchange rate stability enhances FDI, the empirical support associated with this argument is rather weak. Also new theoretical perspectives point to a more ambiguous relationship between exchange rate volatility and FDI flows.

Gianluigi Giorgioni

244

INSTITUTIONAL INVESTORS AND STOCK MARKET VOLATILITY*  

E-print Network

INSTITUTIONAL INVESTORS AND STOCK MARKET VOLATILITY* XAVIER GABAIX PARAMESWARAN GOPIKRISHNAN VASILIKI PLEROU H. EUGENE STANLEY We present a theory of excess stock market volatility, in which market movements are due to trades by very large institutional investors in relatively illiquid markets

Stanley, H. Eugene

245

Financial Openness and Business Cycle Volatility  

Microsoft Academic Search

This paper discusses whether the integration of international financial markets affects business cycle fluctuations. In the framework of a new open economy macro-model, we show that the link between financial openness and business cycle volatility depends on the nature of the underlying shock. Empirical evidence supports this conclusion. Our results also show that the link between business cycle volatility and

Claudia M. Buch; Jörg Döpke; Christian Pierdzioch

2002-01-01

246

Volatility Determinants: Heterogeneity, Leverage, and Jumps  

Microsoft Academic Search

We identify three main endogenous determinants in the dynamics of asset price volatility, namely heterogeneity, leverage, and jumps. We find that each of the three components plays a significant role in volatility forecasting and neglecting one of them is detrimental to the forecasting performance. Importantly, we find remarkable forecasting power for the negative past returns at all the considered frequencies,

Fulvio Corsi; Roberto Reno

247

An Overview of Volatiles in Bulk Silicate Mars  

NASA Astrophysics Data System (ADS)

Mars is distinctly richer in moderately volatile elements (e.g., alkalis) compared to Earth, but the planets have similar abundances of highly volatile elements. Half of the bulk inventory of incompatible volatile species is in the martian crust.

Taylor, G. J.

2014-11-01

248

Lunar Volatiles: An Earth-Moon Perspective  

NASA Technical Reports Server (NTRS)

It has generally been accepted that the Moon is depleted in volatile elements. However, the recent discovery of measurable water in lunar glasses and apatites suggests that volatiles are not as depleted as was once thought. And, in fact, some authors have claimed that water contents of the lunar and terrestrial mantles are similar. Moderately volatile alkali elements may have a bearing on this issue. In general, bulk Moon alkalis are depleted relative to the bulk silicate Earth. Although the bulk lunar chemical composition is difficult to reconstruct, good correlations of alkali elements with refractory lithophile incompatible trace elements make this conclusion robust. These observations have been taken to mean that the Moon overall is depleted in volatiles relative to the Earth. Since water is more volatile than any of the alkali elements, presumably this conclusion is true for water, or even more so.

Jones, John H.

2011-01-01

249

Wall-loss distribution of charge breeding ions in an electron cyclotron resonance ion sourcea)  

NASA Astrophysics Data System (ADS)

We investigated the ion-loss distribution on the sidewall of an electron cyclotron resonance (ECR) plasma chamber using the 18-GHz ECR charge breeder at the Tokai Radioactive Ion Accelerator Complex (TRIAC). Similarities and differences between the ion-loss distributions (longitudinal and azimuthal) of different ion species (i.e., radioactive 111In1+ and 140Xe1+ ions that are typical volatile and nonvolatile elements) was qualitatively discussed to understand the element dependence of the charge breeding efficiency. Especially, the similarities represent universal ion loss characteristics in an ECR charge breeder, which are different from the loss patterns of electrons on the ECRIS wall.

Jeong, S. C.; Oyaizu, M.; Imai, N.; Hirayama, Y.; Ishiyama, H.; Miyatake, H.; Niki, K.; Okada, M.; Watanabe, Y. X.; Otokawa, Y.; Osa, A.; Ichikawa, S.

2012-02-01

250

Wall-loss distribution of charge breeding ions in an electron cyclotron resonance ion source.  

PubMed

We investigated the ion-loss distribution on the sidewall of an electron cyclotron resonance (ECR) plasma chamber using the 18-GHz ECR charge breeder at the Tokai Radioactive Ion Accelerator Complex (TRIAC). Similarities and differences between the ion-loss distributions (longitudinal and azimuthal) of different ion species (i.e., radioactive (111)In(1+) and (140)Xe(1+) ions that are typical volatile and nonvolatile elements) was qualitatively discussed to understand the element dependence of the charge breeding efficiency. Especially, the similarities represent universal ion loss characteristics in an ECR charge breeder, which are different from the loss patterns of electrons on the ECRIS wall. PMID:22380251

Jeong, S C; Oyaizu, M; Imai, N; Hirayama, Y; Ishiyama, H; Miyatake, H; Niki, K; Okada, M; Watanabe, Y X; Otokawa, Y; Osa, A; Ichikawa, S

2012-02-01

251

Analysis of volatile organic compounds of ‘Fuji’ apples following electron beam irradiation and storage  

NASA Astrophysics Data System (ADS)

The volatile organic compounds of non-irradiated and electron-beam irradiated 'Fuji' apples (Malus domestica Borkh.) at 0, 0.5, and 1 kGy were isolated through simultaneous distillation extractions and analyzed using gas chromatograph-mass spectrometry. A total of 53 volatile organic compounds were characterized in 0 and 1 kGy irradiated samples, whereas two more compounds related to ketone and terpenoid group were identified in 0.5 kGy irradiated samples. The contents of volatile compounds were 24.33, 36.49, and 35.28 mg/kg in 0, 0.5, and 1 kGy irradiated samples, respectively. The major compounds identified were butanol, hexanal, [E]-2-hexenal, and hexanol in all samples. The relative content of alcohol increased after 30 days of storage in all samples, whereas that of aldehyde decreased. Although the contents of some volatile compounds were changed by electron-beam irradiation, the total yield and major flavor compounds of irradiated 'Fuji' apples were similar to, or even greater than, those of the control. Therefore, the application of e-beam irradiation if required for microbial decontamination of 'Fuji' apples is an acceptable method as it does not bring about any major quantitative changes of volatile organic compounds.

Song, Hyun-Pa; Shim, Sung-Lye; Lee, Sun-Im; Kim, Dong-Ho; Kwon, Joong-Ho; Kim, Kyong-Su

2012-08-01

252

Volatile organic compound sensing devices  

DOEpatents

Apparatus employing vapochromic materials in the form of inorganic double complex salts which change color reversibly when exposed to volatile organic compound (VOC) vapors is adapted for VOC vapor detection, VOC aqueous matrix detection, and selective VOC vapor detection. The basic VOC vapochromic sensor is incorporated in various devices such as a ground probe sensor, a wristband sensor, a periodic sampling monitor, a soil/water penetrometer, an evaporative purge sensor, and various vacuum-based sensors which are particularly adapted for reversible/reusable detection, remote detection, continuous monitoring, or rapid screening of environmental remediation and waste management sites. The vapochromic sensor is used in combination with various fiber optic arrangements to provide a calibrated qualitative and/or quantitative indication of the presence of VOCs. 15 figs.

Lancaster, G.D.; Moore, G.A.; Stone, M.L.; Reagen, W.K.

1995-08-29

253

Volatile organic compound sensing devices  

DOEpatents

Apparatus employing vapochromic materials in the form of inorganic double complex salts which change color reversibly when exposed to volatile organic compound (VOC) vapors is adapted for VOC vapor detection, VOC aqueous matrix detection, and selective VOC vapor detection. The basic VOC vapochromic sensor is incorporated in various devices such as a ground probe sensor, a wristband sensor, a periodic sampling monitor, a soil/water penetrometer, an evaporative purge sensor, and various vacuum-based sensors which are particularly adapted for reversible/reusable detection, remote detection, continuous monitoring, or rapid screening of environmental remediation and waste management sites. The vapochromic sensor is used in combination with various fiber optic arrangements to provide a calibrated qualitative and/or quantitative indication of the presence of VOCs.

Lancaster, Gregory D. (Idaho Falls, ID); Moore, Glenn A. (Idaho Falls, ID); Stone, Mark L. (Idaho Falls, ID); Reagen, William K. (Stillwater, MN)

1995-01-01

254

Microdistillation and analysis of volatiles from eight ornamental Salvia taxa.  

PubMed

Volatile compounds from seven Salvia species and one interspecific hybrid growing at the Dallas Arboretum and Botanical Garden, Texas, US. Salvia coccinea, S. farinacea, S. greggii, S. leucantha, S. longispicata x farinacea, S. madrensis, S. roemeriana and S. splendens were investigated for their chemical compositions using a microdistillation technique. Volatiles were analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC/MS). One hundred and twenty seven compounds were identified representing 94.3-99.7% of the oils. The major components in each of the seven species were as follows: S. coccinea (Z)-3-hexenal (31%), viridiflorol (19%); S. farinacea 1-octen-3-ol (30%) and (Z)-3-hexenal (23%); S. greggii 1,8-cineole (22%), borneol (17%), camphene (11%) and alpha-pinene (10%); S. leucantha limonene (35%) and alpha-pinene (17%); S. longispicata x farinacea 1-octen-3-ol (50%) and (Z)-3-hexenal (24%); S. madrensis (Z)-3-hexenal (53%); S. roemeriana limonene (49%) and alpha-pinene (20%); and S. splendens (Z)-3-hexenal (36%), 2,5-dimethoxy-p-cymene (19%) and linalool (11%). The microdistillation method was fast, practical and a useful technique that enabled the isolation of the volatiles in samples when only limited quantities were available. PMID:20923001

Tabanca, Nurhayat; Demirci, Betul; Turner, Jimmy L; Pounders, Cecil; Demirci, Fatih; Ba?er, Kemal Hüsnü Can; Wedge, David E

2010-09-01

255

The ESA Lunar Lander and the search for Lunar Volatiles  

NASA Astrophysics Data System (ADS)

Following the Apollo era the moon was considered a volatile poor body. Samples collected from the Apollo missions contained only ppm levels of water formed by the interaction of the solar wind with the lunar regolith [1]. However more recent orbiter observations have indicated that water may exist as water ice in cold polar regions buried within craters at concentrations of a few wt. % [2]. Infrared images from M3 on Chandrayaan-1 have been interpreted as showing the presence of hydrated surface minerals with the ongoing hydroxyl/water process feeding cold polar traps. This has been supported by observation of ephemeral features termed "space dew" [3]. Meanwhile laboratory studies indicate that water could be present in appreciable quantities in lunar rocks [4] and could also have a cometary source [5]. The presence of sufficient quantities of volatiles could provide a resource which would simplify logistics for long term lunar missions. The European Space Agency (ESA's Directorate of Human Spaceflight and Operations) have provisionally scheduled a robotic mission to demonstrate key technologies to enable later human exploration. Planned for launch in 2018, the primary aim is for precise automated landing, with hazard avoidance, in zones which are almost constantly illuminated (e.g. at the edge of the Shackleton crater at the lunar south pole). These regions would enable the solar powered Lander to survive for long periods > 6 months, but require accurate navigation to within 200m. Although landing in an illuminated area, these regions are close to permanently shadowed volatile rich regions and the analysis of volatiles is a major science objective of the mission. The straw man payload includes provision for a Lunar Volatile and Resources Analysis Package (LVRAP). The authors have been commissioned by ESA to conduct an evaluation of possible technologies to be included in L-VRAP which can be included within the Lander payload. Scientific aims are to demonstrate the extraction of volatiles and determine the volatile inventory of the moon with a view for future In-Situ Resource Utilization (ISRU). Surface samples will be collected by a robotic arm with the possibility of a rover to collect more distant samples. The concentration, chemical and accurate isotopic ratios (D/H, 12C/13C, 15N/14N, 18O/16O and noble gases) of liberated volatiles will be determined, possibly using similar technology to the Philae comet lander of the Rosetta mission [6]. An additional aim is the monitoring of the chemical and isotopic composition of the tenuous lunar atmosphere [7] which will become contaminated by active human exploration. The lunar atmosphere will provide information on the processes involved in forming lunar volatiles and their concentration mechanisms. Modelling the effects of contamination from the Lander is an essential part of this study so that these can be recognized and minimized.

Morse, A. D.; Barber, S. J.; Pillinger, J. M.; Sheridan, S.; Wright, I. P.; Gibson, E. K.; Merrifield, J. A.; Waltham, N. R.; Waugh, L. J.; Pillinger, C. T.

2011-10-01

256

Breath measurements as volatile organic compound biomarkers.  

PubMed Central

A brief review of the uses of breath analysis in studies of environmental exposure to volatile organic compounds (VOCs) is provided. The U.S. Environmental Protection Agency's large-scale Total Exposure Assessment Methodology Studies have measured concentrations of 32 target VOCs in the exhaled breath of about 800 residents of various U.S. cities. Since the previous 12-hr integrated personal air exposures to the same chemicals were also measured, the relation between exposure and body burden is illuminated. Another major use of the breath measurements has been to detect unmeasured pathways of exposure; the major impact of active smoking on exposure to benzene and styrene was detected in this way. Following the earlier field studies, a series of chamber studies have provided estimates of several important physiological parameters. Among these are the fraction, f, of the inhaled chemical that is exhaled under steady-state conditions and the residence times. tau i in several body compartments, which may be associated with the blood (or liver), organs, muscle, and fat. Most of the targeted VOCs appear to have similar residence times of a few minutes, 30 min, several hours, and several days in the respective tissue groups. Knowledge of these parameters can be helpful in estimating body burden from exposure or vice versa and in planning environmental studies, particularly in setting times to monitor breath in studies of the variation with time of body burden. Improvements in breath methods have made it possible to study short-term peak exposure situations such as filling a gas tank or taking a shower in contaminated water. PMID:8933027

Wallace, L; Buckley, T; Pellizzari, E; Gordon, S

1996-01-01

257

Ion composition and chemistry  

NASA Astrophysics Data System (ADS)

Measurements from the Vega and Giotto probes are used to study the composition and chemistry of Comet Halley. The missing parent molecules of the C+ and S+ ions which are very abundant in the outer coma of Comet Halley at a radial distance of 100,000 km are examined. Consideration is given to the atomic ions, C+, S+, He+, and Na+, the molecular ions, NH4(+), H2CN(+), and HCS(+), formaldehyde polymers and polycylic aromatic hydrogen carbons. It is suggested that the deficiency of N2 and NH3(+) and the abundance of CO and CO2 with a significant amount of H2CO cloud result from the condensation of volatile ices in the solar nebula.

Ip, W.-H.

258

Selenium detoxification by volatilization and precipitation in aquatic plants  

SciTech Connect

The narrow margin of requirement and toxicity for selenium makes it a difficult pollution problem to solve. Selenium bioaccumulation has been a major threat to wildlife in California and is becoming a major concern in the San Francisco Bay/Estuaries. Despite the past efforts in Se nutrition, chemistry, and remediation, its toxicity and detoxification mechanism(s) in wildlife, particularly primary producers, is still unclear, due to a lack of understanding in Se biochemistry. This is becoming a critical issue in assessing Se risk and remediation. To address this gap, the authors have been characterizing Se speciation and its linkage to detoxification mechanism(s) of two indigenous aquatic plants, duckweed (Lemna minor) and a microphyte (Chlorella). Using GT-MS analysis, they found that Chlorella monocultures transformed Se oxyanions into volatile dimethylselenide and dimethyidiselenide and into insoluble So at extremely high Se (up to 750 ppm) concentrations. This alga did not accumulate selenomethionine which is among the most toxic forms of Se to wildlife. Dimethylsulfide was also volatilized, consistent with the hypothesis that dimethylsulfide/dimethylselenide emissions share a similar biochemical pathway. Se-treated Chlorella biomass released dimethylsulfide/dimethylselenide upon alkaline hydrolysis, suggesting the presence of dimethylsulfonium and dimethylselenonium propionates. Dimethylsulfoniumpropionate is known as an osmoprotectant in marine phytoplankton and as a major contributor to global biogenic dimethylsulfide emissions. Dimethylselenoniumpropionate has not been identified previously and may be a byproduct of dimethylsulfoniumpropionate synthesis. The unusual Se tolerance of Chlorella may be due to its ability to volatilize and precipitate Se. Such activities may be utilized for in situ Se bioremediation. Similar investigations with duckweed is underway.

Fan, T.W.M.; Higashi, R.M. [Univ. of California, Davis, CA (United States)

1995-12-31

259

Native American Studies Major Major Advisors  

E-print Network

Native American Studies Major Major Advisors Laura Jimenez-Olvera & Dewey St. Germaine 532 & 530://ethnicstudies.berkeley.edu/ Undergraduate Program The Native American Studies Program exists to broaden the understanding of students interested in the history, culture, and contemporary situations of Native Americans in the United States

Walker, Matthew P.

260

Volatile components associated with bacterial spoilage of tropical prawns.  

PubMed

Analysis of headspace volatiles by gas chromatography/mass spectrometry from king (Penaeus plebejus), banana (P. merguiensis), tiger (P. esculentus/semisulcatus) and greasy (Metapenaeus bennettae) prawns stored in ice or ice slurry, which is effectively an environment of low oxygen tension, indicated the presence of amines at the early stages of storage (less than 8 days) irrespective of the nature of the storage media. Esters were more prevalent in prawns stored on ice (normal oxygen conditions) at the latter stages of storage (more than 8 days) and were only produced by Pseudomonas fragi, whereas sulphides and amines occurred whether the predominant spoilage organism was Ps. fragi or Shewanella putrefaciens. The free amino acid profiles of banana and king prawns were high in arginine (12-14%) and low in cysteine (0.1-0.17%) and methionine (0.1-0.2%). Filter sterilised raw banana prawn broth inoculated with a total of 15 cultures of Ps. fragi and S. putrefaciens and incubated for two weeks at 5 degrees C, showed the presence of 17 major compounds in the headspace volatiles analysed using gas chromatography/mass spectrometry (GC/MS). These were mainly amines, sulphides, ketones and esters. Principal Component Analysis of the results for the comparative levels of the volatiles produced by pure cultures, inoculated into sterile prawn broth, indicated three subgroupings of the organisms; I, Ps. fragi from a particular geographic location; II, S. putrefaciens from another geographic location; and III, a mixture of Ps. fragi and S. putrefaciens from different geographic locations. The sensory impression created by the cultures was strongly related to the chemical profile as determined by GC/MS. Organisms, even within the same subgrouping classified as identical by the usual tests, produced a different range of volatiles in the same uniform substrate. PMID:9706797

Chinivasagam, H N; Bremner, H A; Wood, A F; Nottingham, S M

1998-06-30

261

Investigation of the volatile constituents of different Gynura species from two Chinese origins by SPME/GC-MS.  

PubMed

GC-MS analyses of the volatile constituents obtained by solid phase microextraction (SPME) of two Gynura species, i.e., G. divaricata and G. bicolor, collected from Nanjing and Nanping areas in the east of China, enabled the identification of more than 50 different components. Generally, a higher contents of sesquiterpene compounds such as beta-caryophyllene, alpha-caryophyllene and alpha-copaene were found in G. bicolor than in G. divaricata, regardless of their origin. Qualitatively, the detected major volatiles of G. bicolor and G. divaricata originating from Nanjing were the same, i.e., beta-caryophyllene, alpha-caryophyllene, alpha-copaene, alpha-pinene and beta-pinene. The volatile profile of a third species, G. medica, also originating from Nanjing was different with sesquiterpenes gamma-cadinene, beta-caryophyllene, elixene and monoterpene limonene as the major components. The volatile profiles of G. bicolor and G. divaricata originating from Nanping were more diverse. For both species beta-caryophyllene, alpha-copaene and limonene were the major volatiles, but G. bicolor also produced gamma-caryophyllene and carvone as major constituents, whereas for G. divariata o-cymene was detected. Overall, these results indicate that the biosynthesis of volatiles by Gynura species is not only species related, but is also possibly influenced by the local environmental conditions of growth. PMID:22799100

Chen, Jian; Adams, An; Mangelinckx, Sven; Ren, Bing-Ru; Li, Wei-lin; Wang, Zheng-tao; De Kimpe, Norbert

2012-05-01

262

Changes in the chemical composition of volatiles released by the flowers and fruits of the red raspberry ( Rubus idaeus) cultivar glen prosen  

Microsoft Academic Search

Volatiles at various stages of inflorescence development, bud formation, flowering, fruit formation and ripening of a red raspberry, were entrained on the porous polymer Tenax TA and analysed by thermal desorption-gas chromatography-mass spectrometry. Major classes of compound identified included aliphatic and aromatic hydrocarbons, aldehydes, ketones, alcohols and esters, monoterpenes and sesquiterpenes. As the inflorescences matured, levels of green leaf volatiles

G. W. Robertson; D. W. Griffiths; J. A. T. Woodford; A. N. E. Birch

1995-01-01

263

Monitoring Trace Contaminants in Air Via Ion Trap Mass Spectrometry  

NASA Technical Reports Server (NTRS)

Recent passage of the Clean Air Act with its stricter regulation of toxic gas emissions, and the ever-growing number of applications which require faster turnaround times between sampling and analysis are two major factors which are helping to drive the development of new instrument technologies for in-situ, on-line, real-time monitoring. The ion trap, with its small size, excellent sensitivity, and tandem mass spectrometry capability is a rapidly evolving technology which is well-suited for these applications. In this paper, we describe the use of a commercial ion trap instrument for monitoring trace levels of chlorofluorocarbons (CFCs) and volatile organic compounds (VOCs) in air. A number of sample introduction devices including a direct transfer line interface, short column GC, and a cryotrapping interface are employed to achieve increasing levels of sensitivity. MS, MS/MS, and MS/MS/MS methods are compared to illustrate trade-offs between sensitivity and selectivity. Filtered Noise Field (FNF) technology is found to be an excellent means for achieving lower detection limits through selective storage of the ion(s) of interest during ionization. Figures of merit including typical sample sizes, detection limits, and response times are provided. The results indicate the potential of these techniques for atmospheric assessments, the High Speed Research Program, and advanced life support monitoring applications for NASA.

Palmer, Peter T.; Karr, Dane; Pearson, Richard; Valero, Gustavo; Wong, Carla

1995-01-01

264

On the mechanisms controlling the formation and properties of volatile particles in aircraft wakes  

NASA Astrophysics Data System (ADS)

New observations taken in aircraft wakes, including the DLR ATTAS, provide strong constraints on models of aircraft plume aerosols. Using a comprehensive microphysics code, we have performed sensitivity studies to identify the key microphysical mechanisms acting in such plumes. Analysis of these simulations reveals that the largest volatile plume particles—those most likely to contribute to the background abundance of condensation nuclei—are dominated by ion-mode particles when chemiions are included. Moreover, such modeling demonstrates that standard treatments of plume microphysics—in the absence of chemiions—fails to explain field measurements. The principal factor controlling the population of ultrafine plume particles is the number of chemiions emitted by the aircraft engines. Since the ions are a byproduct of the combustion itself, and their abundance in the exhaust stream is controlled by ion-ion recombination, the initial ion concentrations—and so the eventual emission indices for ion-mode particles—are expected to be relatively invariant. Our results indicate that reductions in fuel sulfur content, while not likely to lower the total number of volatile particles emitted, would decrease the size of the ion-mode particles in fresh aircraft wakes, reducing their atmospheric lifetimes and potential environmental effects.

Yu, Fangqun; Turco, Richard P.; Kärcher, Bernd; Schröder, Franz P.

265

Identification of Major Histocompatibility Complex-Regulated Body Odorants by Statistical Analysis of a Comparative Gas Chromatography/Mass Spectrometry Experiment  

SciTech Connect

Gas chromatography (GC), combined with mass spectrometry (MS) detection, is a powerful analytical technique that can be used to separate, quantify, and identify volatile compounds in complex mixtures. This paper examines the application of GC-MS in a comparative experiment to identify volatiles that differ in concentration between two groups. A complex mixture might comprise several hundred or even thousands of volatile compounds. Because their number and location in a chromatogram generally are unknown, and because components overlap in populous chromatograms, the statistical problems offer significant challenges beyond traditional two-group screening procedures. We describe a statistical procedure to compare two-dimensional GC-MS profiles between groups, which entails (1) signal processing: baseline correction and peak detection in single ion chromatograms; (2) aligning chromatograms in time; (3) normalizing differences in overall signal intensities; and (4) detecting chromatographic regions that differ between groups. Compared to existing approaches, the proposed method is robust to errors made at earlier stages of analysis, such as missed peaks or slightly misaligned chromatograms. To illustrate the method, we identify differences in GC-MS chromatograms of ether-extracted urine collected from two nearly identical inbred groups of mice, to investigate the relationship between odor and genetics of the major histocompatibility complex.

Willse, Alan R.; Belcher, Ann; Preti, George; Wahl, Jon H.; Thresher, Miranda; Yang, Peter; Yamazaki, Kunio; Beauchamp, Gary

2005-04-15

266

Potential interaction between the volatile and non-volatile fractions on the in vitro antimicrobial activity of three South African Pelargonium (Geraniaceae) species.  

PubMed

Previous studies have reported promising antimicrobial efficacy for the essential oils and solvent extracts of several indigenous Pelargonium species. This study aimed to determine if any pharmacological interaction (e.g. synergism or antagonism) exists between the volatile and non-volatile components when the different fractions were investigated. The antimicrobial activity of the following fractions were tested; the essential oil prepared by hydrodistillation (EO), non-volatile fraction (NV), prepared by extraction of plant material remaining in the distilling apparatus (having no or negligible volatile constituents) and solvent extracts prepared from fresh (FC) and dried (DC) plant material containing both volatile and non-volatile constituents. Pelargonium quercifolium oil was dominated by p-cymene (42.1%) and viridiflorol (16.9%), while P. graveolens and P. tomentosum oil had high levels of isomenthone (84.0 and 58.8%, respectively). Menthone was noted as a major constituent in the P. tomentosum EO sample. It was evident from the results that the presence of volatile constituents in the three species; P. graveolens, P. quercifolium and P. tomentosum is generally not a pre-requisite for antimicrobial activity. The most significant variations of antimicrobial activity were noted for P. tomentosum where poorer activity was noted for the FC and EO fractions against Bacillus cereus and Candida albicans. Studies on Staphylococcus aureus, however, showed the converse, where best activity was noted for the FC fraction (3.0 mg/mL). For P. quercifolium, the DC fraction indicated a notable increase in anti-staphylococcal activity (2.0 mg/mL) when compared with the FC (8.0 mg/mL) and EO (16.0 mg/mL) fractions. For P. tomentosum, the FC fraction indicated much lower antimicrobial activity (against both B. cereus and C. albicans) when compared with all other fractions, suggesting that the essential oils may impact negatively on the antimicrobial activity when tested against these two pathogens. PMID:20922997

Lalli, Jacqueline Y; Viljoen, Alvaro M; Van Vuuren, Sandy F

2010-09-01

267

Volatile-Mediated Killing of Arabidopsis thaliana by Bacteria Is Mainly Due to Hydrogen Cyanide? †  

PubMed Central

The volatile-mediated impact of bacteria on plant growth is well documented, and contrasting effects have been reported ranging from 6-fold plant promotion to plant killing. However, very little is known about the identity of the compounds responsible for these effects or the mechanisms involved in plant growth alteration. We hypothesized that hydrogen cyanide (HCN) is a major factor accounting for the observed volatile-mediated toxicity of some strains. Using a collection of environmental and clinical strains differing in cyanogenesis, as well as a defined HCN-negative mutant, we demonstrate that bacterial HCN accounts to a significant extent for the deleterious effects observed when growing Arabidopsis thaliana in the presence of certain bacterial volatiles. The environmental strain Pseudomonas aeruginosa PUPa3 was less cyanogenic and less plant growth inhibiting than the clinical strain P. aeruginosa PAO1. Quorum-sensing deficient mutants of C. violaceum CV0, P. aeruginosa PAO1, and P. aeruginosa PUPa3 showed not only diminished HCN production but also strongly reduced volatile-mediated phytotoxicity. The double treatment of providing plants with reactive oxygen species scavenging compounds and overexpressing the alternative oxidase AOX1a led to a significant reduction of volatile-mediated toxicity. This indicates that oxidative stress is a key process in the physiological changes leading to plant death upon exposure to toxic bacterial volatiles. PMID:21115704

Blom, Dirk; Fabbri, Carlotta; Eberl, Leo; Weisskopf, Laure

2011-01-01

268

Influence of sporophore development, damage, storage, and tissue specificity on the enzymic formation of volatiles in mushrooms (Agaricus bisporus).  

PubMed

The enzymic oxidation of the polyunsaturated fatty acid-linoleic acid leads, in fungi, to the formation of a unique class of nonconjugated hydroperoxides, which are cleaved to form eight-carbon volatiles characteristic of mushroom and fungal flavor. However, the enzymes involved in this biosynthetic pathway, the bioavailability of the fatty acid substrate, and the occurrence of the reaction products (hydroperoxides and eight-carbon volatiles) are not fully understood. This study investigated the lipids, fatty acids, and hydroperoxide levels, as well as eight-carbon volatile variations in the fungal model Agaricus bisporus, according to four parameters: sporophore development, postharvest storage, tissue type, and damage. Eight-carbon volatiles were measured using solid phase microextraction and gas chromatography-mass spectrometry. Tissue disruption had a major impact on the volatile profile, both qualitatively and quantitatively; 3-octanone was identified as the main eight-carbon volatile in whole and sliced sporophore, an observation overlooked in previous studies due to the use of tissue disruption and solvent extraction for analysis. Fatty acid oxidation and eight-carbon volatile emissions decreased with sporophore development and storage, and differed according to tissue type. The release of 1-octen-3-ol and 3-octanone by incubation of sporophore tissue homogenate with free linoleic acid was inhibited by acetylsalicylic acid, providing evidence for the involvement of a heme-dioxygenase in eight-carbon volatile production. PMID:19326947

Combet, Emilie; Henderson, Janey; Eastwood, Daniel C; Burton, Kerry S

2009-05-13

269

Prey and Non-prey Arthropods Sharing a Host Plant: Effects on Induced Volatile Emission and Predator Attraction  

PubMed Central

It is well established that plants infested with a single herbivore species can attract specific natural enemies through the emission of herbivore-induced volatiles. However, it is less clear what happens when plants are simultaneously attacked by more than one species. We analyzed volatile emissions of lima bean and cucumber plants upon multi-species herbivory by spider mites (Tetranychus urticae) and caterpillars (Spodoptera exigua) in comparison to single-species herbivory. Upon herbivory by single or multiple species, lima bean and cucumber plants emitted volatile blends that comprised mostly the same compounds. To detect additive, synergistic, or antagonistic effects, we compared the multi-species herbivory volatile blend with the sum of the volatile blends induced by each of the herbivore species feeding alone. In lima bean, the majority of compounds were more strongly induced by multi-species herbivory than expected based on the sum of volatile emissions by each of the herbivores separately, potentially caused by synergistic effects. In contrast, in cucumber, two compounds were suppressed by multi-species herbivory, suggesting the potential for antagonistic effects. We also studied the behavioral responses of the predatory mite Phytoseiulus persimilis, a specialized natural enemy of spider mites. Olfactometer experiments showed that P. persimilis preferred volatiles induced by multi-species herbivory to volatiles induced by S. exigua alone or by prey mites alone. We conclude that both lima bean and cucumber plants effectively attract predatory mites upon multi-species herbivory, but the underlying mechanisms appear different between these species. PMID:18185960

Hordijk, Cornelis A.; Posthumus, Maarten A.; Dicke, Marcel

2008-01-01

270

Flower Volatiles, Crop Varieties and Bee Responses  

PubMed Central

Pollination contributes to an estimated one third of global food production, through both the improvement of the yield and the quality of crops. Volatile compounds emitted by crop flowers mediate plant-pollinator interactions, but differences between crop varieties are still little explored. We investigated whether the visitation of crop flowers is determined by variety-specific flower volatiles using strawberry varieties (Fragaria x ananassa Duchesne) and how this affects the pollination services of the wild bee Osmia bicornis L. Flower volatile compounds of three strawberry varieties were measured via headspace collection. Gas chromatography showed that the three strawberry varieties produced the same volatile compounds but with quantitative differences of the total amount of volatiles and between distinct compounds. Electroantennographic recordings showed that inexperienced females of Osmia bicornis had higher antennal responses to all volatile compounds than to controls of air and paraffin oil, however responses differed between compounds. The variety Sonata was found to emit a total higher level of volatiles and also higher levels of most of the compounds that evoked antennal responses compared with the other varieties Honeoye and Darselect. Sonata also received more flower visits from Osmia bicornis females under field conditions, compared with Honeoye. Our results suggest that differences in the emission of flower volatile compounds among strawberry varieties mediate their attractiveness to females of Osmia bicornis. Since quality and quantity of marketable fruits depend on optimal pollination, a better understanding of the role of flower volatiles in crop production is required and should be considered more closely in crop-variety breeding. PMID:23977347

Klatt, Bjorn K.; Burmeister, Carina; Westphal, Catrin; Tscharntke, Teja; von Fragstein, Maximillian

2013-01-01

271

Securing non-volatile memory regions  

DOEpatents

Methods, apparatus and articles of manufacture to secure non-volatile memory regions are disclosed. An example method disclosed herein comprises associating a first key pair and a second key pair different than the first key pair with a process, using the first key pair to secure a first region of a non-volatile memory for the process, and using the second key pair to secure a second region of the non-volatile memory for the same process, the second region being different than the first region.

Faraboschi, Paolo; Ranganathan, Parthasarathy; Muralimanohar, Naveen

2013-08-20

272

Analyzing volatile compounds in dairy products.  

PubMed

Volatile compounds give the first indication of the flavor in a dairy product. Volatiles are isolated from the sample matrix and then analyzed by chromatography, sensory methods or an electronic nose. Isolation may be performed by solvent extraction or headspace analysis, and gas chromatography is often employed with various detectors to identify odorants. The human nose is also used as a detector, and electronic noses are being developed to qualitate and quantitate volatiles. A reliable technique for analyzing odorants in dairy products has not yet been invented. PMID:24549967

Tunick, Michael H

2014-07-01

273

Concentrations of Volatiles in the Lunar Regolith  

NASA Technical Reports Server (NTRS)

To set lower and upper limits on the overall amounts and types of volatiles released during heating of polar regolith, we examined the data for equatorial lunar regolith and for the compositions of comets. The purpose, specifically, was to answer these questions: 1. Upper/Lower limits and 'best guess' for total amount of volatiles (by weight %) released from lunar regolith up to 150C 2. Upper/Lower limit and 'best guess' for composition of the volatiles released from the lunar regolith by weight %

Taylor, Jeff; Taylor, Larry; Duke, Mike

2007-01-01

274

The effects of volatile anesthetics on synaptic and extrasynaptic GABA-induced neurotransmission.  

PubMed

Examination of volatile anesthetic actions at single synapses provides more direct information by reducing interference by surrounding tissue and extrasynaptic modulation. We examined how volatile anesthetics modulate GABA release by measuring spontaneous or miniature GABA-induced inhibitory postsynaptic currents (mIPSCs, sIPSCs) or by measuring action potential-evoked IPSCs (eIPSCs) at individual synapses. Halothane increased both the amplitude and frequency of sIPSCs. Isoflurane and enflurane increased mIPSC frequency while sevoflurane had no effect. These anesthetics did not alter mIPSC amplitudes. Halothane increased the amplitude of eIPSCs, with a decrease in failure rate (Rf) and paired-pulse ratio. In contrast, isoflurane and enflurane decreased the eIPSC amplitude and increased Rf, while sevoflurane decreased the eIPSC amplitude without affecting Rf. Volatile anesthetics did not change kinetics except for sevoflurane, suggesting that presynaptic mechanisms dominate changes in neurotransmission. Each anesthetic showed somewhat different GABA-induced response and these results suggest that GABA-induced synaptic transmission cannot have a uniformly common site of action as suggested for volatile anesthetics. In contrast, all volatile anesthetics concentration-dependently enhanced the GABA-induced extrasynaptic currents. Extrasynaptic receptors containing ?4 and ?5 subunits are reported to have high sensitivities to volatile anesthetics. Also, inhibition of GABA uptake by volatile anesthetics results in higher extracellular GABA concentration, which may lead to prolonged activation of extrasynaptic GABAA receptors. The extrasynaptic GABA-induced receptors may be major site of volatile anesthetic-induced neurotransmission. This article is part of a Special Issue entitled 'Extrasynaptic ionotropic receptors'. PMID:22925739

Kotani, Naoki; Akaike, Norio

2013-04-01

275

Volatile Evolution of Magma Associated with the Solchiaro Eruption in the Phlegrean Volcanic District (Italy)  

NASA Astrophysics Data System (ADS)

The Phlegrean volcanic district (PVD) in southern Italy is one of the best known volcanic hazard areas in the world. More than 1.5 million people live in close proximity to the volcanic centers. The PVD comprises three volcanic fields: the Campi Flegrei caldera and the islands of Ischia and Procida. The area contains many volcanic centers (cinder cones, tuff rings, calderas) and has been the site of episodic volcanic activity for more than 60 ka. Some of these eruptions have been extremely violent. We studied volatiles in the magma associated with the Solchiaro eruption on the Island of Procida, Italy, to gain a better understanding of the relationship between eruptive style and intensity and the volatile content of the magma. The Solchiaro eruption is one of the more primitive products erupted in the PVD and provides information on the source of later more evolved magmas associated with this volcanic system. The composition of the magma before eruption was determined by analyzing melt inclusions (MIs) in forsteritic olivine and diopside. Several different types of MIs were observed in both phases. Some MI contained only glass, others contained glass plus one or more bubbles, and some contained glass plus bubbles plus crystals. We analyzed MIs containing only glass and those containing one or two bubbles. The composition of MIs ranges from basaltic to trachy-basaltic. Among major elements potassium shows the highest variability, from 1.48 to 3.73 wt %. Laser ablation-inductively coupled plasma mass spectroscopy (LA-ICPMS) analysis of MIs combined with major element analysis suggest assimilation of LILE and halogens from wallrock. Diopside-hosted MI have a higher H2O content than olivine-hosted MI, based on Secondary Ion Mass Spectrometric (SIMS) analysis. MI in olivine contain from 1.13 to 1.38 wt % H2O. F, Cl, S, CO2 contents are highly variable in both olivine and diopside-hosted MIs. The trend in H2O versus CO2 suggests emplacement of an originally CO2-saturated magma at >5 km that rises through the crust as it is undergoing crystallization. The magma eventually ponds at shallow depths (<1 km) before eruption. The inferred emplacement and crystallization history of magma at Campi Flegrei is similar to what was observed at Mt. St. Helens in the months immediately preceding the May 1980 eruption.

Esposito, R.; Bodnar, R. J.; de Vivo, B.; Lima, A.; Fedele, L.; Shimizu, N.; Belkin, H.

2008-12-01

276

Muscodor albus Volatiles Control Toxigenic Fungi under Controlled Atmosphere (CA) Storage Conditions  

PubMed Central

Muscodor albus, a biofumigant fungus, has the potential to control post-harvest pathogens in storage. It has been shown to produce over 20 volatile compounds with fungicidal, bactericidal and insecticidal properties. However, M. albus is a warm climate endophyte, and its biofumigant activity is significantly inhibited at temperatures below 5 °C. Conidia of seven mycotoxin producing fungi, Aspergillus carbonarius, A. flavus, A. niger, A. ochraceus, Penicillium verrucosum, Fusarium culmorum and F. graminearum, were killed or prevented from germinating by exposure to volatiles from 2 g M. albus-colonized rye grain per L of headspace in sealed glass jars for 24 h at 20 °C. Two major volatiles of M. albus, isobutyric acid (IBA) and 2-methyl-1-butanol (2MB) at 50 ?L/L and 100 ?L/L, respectively, gave differential control of the seven fungi when applied individually at 20 °C. When the fungi were exposed to both IBA and 2MB together, an average of 94% of the conidia were killed or suppressed. In a factorial experiment with controlled atmosphere storage (CA) at 3 °C and 72 h exposure to four concentrations of IBA and 2MB combinations, 50 ?L/L IBA plus 100 ?L/L 2MB killed or suppressed germination of the conidia of all seven fungi. Controlled atmosphere had no significant effect on conidial viability or volatile efficacy. Major volatiles of M. albus may have significant potential to control plant pathogens in either ambient air or CA storage at temperatures below 5 °C. However, combinations of volatiles may be required to provide a broader spectrum of control than individual volatiles. PMID:23443097

Braun, Gordon; Vailati, Matteo; Prange, Robert; Bevis, Eric

2012-01-01

277

Volatile organic compounds in snow in the Quebec-Windsor Corridor  

Microsoft Academic Search

Volatile organic compounds (VOC) were determined in snow to investigate the role of the snowpack as an exchange medium for atmospherically active compounds of anthropogenic and biogenic origin. The major question was which VOC species occur in snow and how the species identity and selected concentrations are related to the sampling area and environmental conditions. Samples were collected using a

G. Kos; P. A. Ariya

2010-01-01

278

Volatile Production by Buds and Corollas of Two Sympatric, Confamilial Plants, Ipomopsis aggregata and Polemonium foliosissimum  

Microsoft Academic Search

We used solid-phase microextraction of headspace samples followed by gas chromatography and mass spectrometry to identify and quantify the major volatile compounds produced by the buds and corollas of Ipomopsis aggregata (Polemoniaceae), and we compared them to a sympatric, confamilial plant species, Polemonium foliosissimum. The two species have distinct floral morphologies and pollinators, but share a common predispersal seed predator

Rebecca E. Irwin; Bob Dorsett

2002-01-01

279

Production of volatile sulfides from freshwater algae and implications for the environment  

Microsoft Academic Search

Dimethyl sulfide (OMS) is the major volatile sulfide (VS) species of biogenic origin released to the atmosphere. Large amounts of OMS can originate from the decomposition of the metabolic precursor Dimethylsulfoniopropionate (DMSP) in marine algae. Quantitatively, the emissions of OMS and other VS to the atmosphere are in the same order of magnitude as atmospheric sulfur from man-made pollution. Therefore

François Caron

1990-01-01

280

Production of volatile sulfides from freshwater algae and implications to the environment  

Microsoft Academic Search

Dimethyl sulfide (DMS) is the major volatile sulfide (VS) species of biogenic origin released to the atmosphere. Large amounts of DMS can originate from the decomposition of the metabolic precursor Dimethylsulfoniopropionate (DMSP) in marine algae. Quantitatively, the emissions of DMS and other VS to the atmosphere are in the same order of magnitude as atmospheric sulfur from man-made pollution. Therefore

Francois Caron

1990-01-01

281

Chemical changes in the non-volatile fraction of Brazilian honeys during storage under tropical conditions  

Microsoft Academic Search

The chemical transformations of the non-volatile fraction of Brazilian honeys during storage in tropical condition were monitored. Five systems, namely: 1 – fresh samples; 2 and 3 – samples heated for 3 and 6 months at 35–40°C; 4 and 5 – samples left under similar conditions to systems 2 and 3, but containing sodium metabisulphite (120ppm), were tested. The major

Ricardo F. A. Moreira; Carlos A. B. De Maria; Márcia Pietroluongo; Luiz C. Trugo

2007-01-01

282

VOLATILE ORGANIC COMPOUNDS AND ISOPRENE OXIDATION PRODUCTS AT A TEMPERATE DECIDUOUS FOREST SITE  

EPA Science Inventory

Biogenic volatile compounds (BVOCs) and their role in atmospheric oxidant formation were investigated at a forest site near Oak Ridge, Tennessee, as part of the Nashville Southern Oxidants Study (SOS) in July 1995. Of 98 VOCs detected, a major fraction were anthropogenic VOCs suc...

283

Analysis of volatile compounds from supercritical extracted soybeans by headspace gas chromatography and thermal desorption of a polymer adsorbent  

Microsoft Academic Search

Soybean flakes were extracted with supercritical carbon dioxide to produce a solvent-free, good-quality soybean oil. Volatile compounds from the supercritical fluid extracted (SFE) oil and from a hexane-extracted crude soybean oil were analyzed by dynamic headspace gas chromatographic methods to deter- mine qualitative differences between the extraction methods. The major differ- ence in the volatile profiles was the higher concentration

Janet M Snyder; Jerry W King

1994-01-01

284

Ammonia volatilization from urea as affected by tropical?based palm oil mill effluent (Pome) and peat  

Microsoft Academic Search

Ammonia (NH3) volatilization is a major pathway of nitrogen (N) loss which limits the efficiency of urea as a fertilizer when surface?applied to soils. High pH and low cation exchange capacity in soils have been identified as the principal causes of NH3 volatilization from urea. The several approaches proposed to correct such inefficiency in urea were, thus far, fundamentally based

K. B. Siva; H. Aminuddin; M. H. A. Husni; A. R. Manas

1999-01-01

285

Seasonal Variation in Volatile Compound Profiles of Preen Gland Secretions of the Dark-eyed Junco ( Junco hyemalis )  

Microsoft Academic Search

Quantitative stir bar sorptive extraction methodology, followed by gas chromatography-mass spectrometry (GC-MS) and element-specific\\u000a atomic emission detection (AED) were utilized to analyze seasonal changes in volatile components of preen oil secretions in\\u000a Junco hyemalis. Juncos were held in long days to simulate breeding conditions, or short days to simulate nonbreeding conditions. Linear\\u000a alcohols (C10–C18) were the major volatile compounds found

Helena A. Soini; Sara E. Schrock; Kevin E. Bruce; Donald Wiesler; Ellen D. Ketterson; Milos V. Novotny

2007-01-01

286

Two terpene synthases are responsible for the major sesquiterpenes emitted from the flowers of kiwifruit (Actinidia deliciosa)  

Microsoft Academic Search

Kiwifruit vines rely on bees for pollen transfer between spatially separated male and female individuals and require synchronized flowering to ensure pollination. Volatile terpene compounds, which are important cues for insect pollinator attraction, were studied by dynamic headspace sampling in the major green-fleshed kiwifruit (Actinidia deliciosa) cultivar 'Hayward' and its male pollinator 'Chieftain'. Terpene volatile levels showed a profile dominated

Niels J. Nieuwenhuizen; Mindy Y. Wang; Adam J. Matich; Sol A. Green; Xiuyin Chen; Yar-Khing Yauk; Lesley L. Beuning; Dinesh A. Nagegowda; Natalia Dudareva; Ross G. Atkinson

2009-01-01

287

Microwave spectra of some volatile organic compounds  

NASA Technical Reports Server (NTRS)

A computer-controlled microwave (MRR) spectrometer was used to catalog reference spectra for chemical analysis. Tables of absorption frequency, peak absorption intensity, and integrated intensity are included for 26 volatile organic compounds, all but one of which contain oxygen.

White, W. F.

1975-01-01

288

VOLATILE ORGANIC ANALYSIS BY DIRECT AQUEOUS INJECTION  

EPA Science Inventory

Gas chromatographic environmental analysis by direct aqueous injection (DAI) was studied for 24 volatile organic analytes (VOAs). Internal standardization was used to determine the precision of analyzing these compounds by DAI. Aequous samples were directly introduced to a gas ch...

289

Reactive flash volatilization of fluid fuels  

DOEpatents

The invention provides methods for the production of synthesis gas. More particularly, various embodiments of the invention relate to systems and methods for volatilizing fluid fuel to produce synthesis gas by using a metal catalyst on a solid support matrix.

Schmidt, Lanny D.; Dauenhauer, Paul J.; Dreyer, Bradon J.; Salge, James R.

2013-01-08

290

TOXIC ORGANIC VOLATILIZATION FROM LAND TREATMENT SYSTEMS  

EPA Science Inventory

Methodology was evaluated for estimating volatilization of toxic organic chemicals from unsaturated soils. Projections were compared with laboratory data for simulated rapid infiltration wastewater treatment systems receiving primary municipal wastewater spiked with a suite of 18...

291

Volatile constituents in a wood pyrolysis oil  

E-print Network

Science VOLATILE CONSTITUTENTS IN A WOOD PYROLYSIS OIL A Thesis SHIH-CHIEN LIN Appro d as to style and content by: (Chairman of Committee) Head of epa tmen (Member Member Nay 1978 442936 ABSTRACT Volatile Constituents in a Wood Pyrolysis Oil..., 1958]. . . . . . . . . . . . 4 Pyrolysis products of cellulose and treated cellulose at 600oC f Chin, 1973]. . . . . . . . . . . . . . . 6 3. Pyrolysis products of lignin at 450-550 C [Allen and Nattil a, 1971] Properties of wood pyrolysis oil. 12...

Lin, Shih-Chien

2012-06-07

292

S&P 100 Index Option Volatility  

Microsoft Academic Search

Using transaction data on the S&P 100 index options, the authors study the effect of valuation simplifications that are commonplace in previous research on the time-series properties of implied market volatility. Using an American-style algorithm that accounts for the discrete nature of the dividends on the S&P 100 index, they find that spurious negative serial correlation in implied volatility changes

Campbell R Harvey; Robert E Whaley

1991-01-01

293

Alternative Models For Conditional Stock Volatility  

Microsoft Academic Search

This paper compares several statistical models for monthly stock return volatility. The focus is on U.S. data from 1834-19:5 because the post-1926 data have been analyzed in more detail by others. Also, the Great Depression had levels of stock volatility that are inconsistent with stationary models for conditional heteroskedasticity, We show the importance of nonlinearities in stock return behavior that

Adrian R. Pagan; G. William Schwert

1990-01-01

294

Mercury volatilization from salt marsh sediments  

Microsoft Academic Search

In situ volatilization fluxes of gaseous elemental mercury, Hg(0), were estimated for tidally exposed salt marsh sediments in the summer at the urban\\/industrial Secaucus High School Marsh, New Jersey Meadowlands (Secaucus, New Jersey) and in the early autumn at a regional background site in the Great Bay estuary (Tuckerton, New Jersey). Estimated daytime sediment-air mercury volatilization fluxes at the Secaucus

Lora M. Smith; John R. Reinfelder

2009-01-01

295

Majority Gate Networks  

Microsoft Academic Search

This paper presents methods for realizing simple threshold functions of n arguments by networks of k-input majority gates, where k?n. An optimal network realization of the 5-argument majority function using 3-input majority gates is given, and it is then generalized by steps with realizations for the (2n-l)-argument majority function (where n = 3, 4, ...) using (2n-3)-input majority gates, and

S. Amarel; G. Cooke; R. O. Winder

1964-01-01

296

Market volatility modeling for short time window  

NASA Astrophysics Data System (ADS)

The gain or loss of an investment can be defined by the movement of the market. This movement can be estimated by the difference between the magnitudes of two stock prices in distinct periods and this difference can be used to calculate the volatility of the markets. The volatility characterizes the sensitivity of a market change in the world economy. Traditionally, the probability density function (pdf) of the movement of the markets is analyzed by using power laws. The contributions of this work is two-fold: (i) an analysis of the volatility dynamic of the world market indexes is performed by using a two-year window time data. In this case, the experiments show that the pdf of the volatility is better fitted by exponential function than power laws, in all range of pdf; (ii) after that, we investigate a relationship between the volatility of the markets and the coefficient of the exponential function based on the Maxwell-Boltzmann ideal gas theory. The results show an inverse relationship between the volatility and the coefficient of the exponential function. This information can be used, for example, to predict the future behavior of the markets or to cluster the markets in order to analyze economic patterns.

de Mattos Neto, Paulo S. G.; Silva, David A.; Ferreira, Tiago A. E.; Cavalcanti, George D. C.

2011-10-01

297

Long-memory volatility in derivative hedging  

NASA Astrophysics Data System (ADS)

The aim of this work is to take into account the effects of long memory in volatility on derivative hedging. This idea is an extension of the work by Fedotov and Tan [Stochastic long memory process in option pricing, Int. J. Theor. Appl. Finance 8 (2005) 381-392] where they incorporate long-memory stochastic volatility in option pricing and derive pricing bands for option values. The starting point is the stochastic Black-Scholes hedging strategy which involves volatility with a long-range dependence. The stochastic hedging strategy is the sum of its deterministic term that is classical Black-Scholes hedging strategy with a constant volatility and a random deviation term which describes the risk arising from the random volatility. Using the fact that stock price and volatility fluctuate on different time scales, we derive an asymptotic equation for this deviation in terms of the Green's function and the fractional Brownian motion. The solution to this equation allows us to find hedging confidence intervals.

Tan, Abby

2006-10-01

298

Ion and neutral mass spectrometry of the isotopic composition of Titan's upper atmosphere: Implications for the atmospheric dynamics and photochemistry, and the evolution of the major species over geological time scales  

NASA Astrophysics Data System (ADS)

The atmosphere of Titan, Saturn's largest moon, is an analog for the Earth's atmosphere in the distant past when life first emerged, and may also be used to study the distant future when the abundance of water in the atmosphere may be reduced by photochemical loss processes associated with climate change. This Dissertation investigates the evolution of Titan's atmosphere utilizing measurements of the stable isotope ratios in molecular nitrogen and methane. The Cassini Ion Neutral Mass Spectrometer (INMS) measures the composition of the ionosphere and neutral atmosphere as it flies through the atmosphere, approaching altitudes as low as 950 km above the surface. INMS measurements of the 14N/15N in N2 as a function of altitude for 30 Titan flybys are compared, using a basic diffusion model, to the Huygens Gas Chromatograph Mass Spectrometer (GCMS) measurement of the 14N/15N in N2 on the surface. This comparison provides the input parameters needed to extrapolate the INMS measurements of 12C/13C in CH4 from the upper atmosphere to the surface where the ratio is within the range of expected primordial values. Although the 12C/13C at Titan is close to the primordial value, escape and photochemistry fractionate the isotope ratio over time. This suggests that methane has been present in Titan's atmosphere for no more than one billion years. A cross-calibration of INMS ion densities with the electron densities measured by the Cassini Radio Plasma Wave Spectrometer (RPWS) constrains the energy response of INMS and provides a new approach for determining the densities of ions in Titan's ionosphere. These ion densities validate an updated coupled Ion-Neutral-Thermal model that constrains the fractionation of the nitrogen isotopes due to photochemistry. Modeling the evolution of the nitrogen isotopes over geological times scales based on chemistry and escape limits the initial 14N/15N to a heavier ratio than the 14N/ 15N observed in the Earth's atmosphere. The methodologies developed for this Dissertation are relevant not only to Titan, but also to Earth. They can be used to evaluate dynamics and photochemistry of the nitrogen isotopes in the upper atmosphere and to define future missions to study the composition of the Earth's thermosphere.

Mandt, Kathleen E.

299

Outgassing and degradation of polyimide induced by swift heavy ion irradiation at cryogenic temperature  

SciTech Connect

Polyimide foils were irradiated with energetic Kr (740 MeV) and Pb (890 MeV) ions at cryogenic temperature (12 K). Beam-induced degradation processes were monitored by residual gas analysis and online infrared spectroscopy. The outgassing components observed at low irradiation temperatures differ in quantity but are similar in mass distribution to those identified at room temperature exposure. Besides CO as major volatile fragment, a significant contribution of short hydrocarbons like C{sub 2}H{sub x} is released. In situ infrared spectroscopy indicates accumulation of CO and CO{sub 2} molecules at 12 K in the foils. During heat-up cycles, most of these frozen gases become mobile and outgas at a temperature between 35 and 55 K. The study is motivated by the application of polyimide foils as insulating material in high radiation environment of the future accelerator facility for antiproton and ion research (FAIR).

Severin, D. [Department of Materials Science, Darmstadt University of Technology, Petersenstr. 23, 64287 Darmstadt (Germany); GSI-Helmholtz Centre for Heavy Ion Research, Planckstr. 1, 64291 Darmstadt (Germany); Balanzat, E. [CIMAP-CIRIL, CEA-CNRS-ENSICAEN, 14050 Caen cedex 4 (France); Ensinger, W. [Department of Materials Science, Darmstadt University of Technology, Petersenstr. 23, 64287 Darmstadt (Germany); Trautmann, C. [GSI-Helmholtz Centre for Heavy Ion Research, Planckstr. 1, 64291 Darmstadt (Germany)

2010-07-15

300

Identification of volatiles in leaves of Alpinia zerumbet 'Variegata' using headspace solid-phase microextraction-gas chromatography-mass spectrometry.  

PubMed

Alpinia zerumbet 'Variegata' is an aromatic medicinal plant, its foliage producing an intense, unique fragrant odor. This study identified 46 volatile compounds in the leaf tissue of this plant using headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS). The major compounds included 1, 8-cineole (43.5%), p-cymene (14.7%), humulene (5.5%), camphor (5.3%), linalool (4.7%), (E)-methyl cinnamate (3.8%), gamma-cadinene (3.3%), humulene oxide II (2.1%) and a-terpineol (1.5%). The majority of the volatiles were terpenoids of which oxygenated monoterpenes were the most abundant, accounting for 57.2% of the total volatiles. Alcohols made up the largest (52.8%) and aldehydes the smallest (0.2%) portions of the volatiles. Many bioactive compounds were present in the volatiles. PMID:25230513

Chen, Jian Yan; Ye, Zheng Mei; Huang, Tian Yi; Chen, Xiao Dan; Li, Yong Yu; Wu, Shao Hua

2014-07-01

301

Gas chromatographic analysis of volatiles in fluid and gas inclusions  

USGS Publications Warehouse

Most geological samples and some synthetic materials contain fluid inclusions. These inclusions preserve for us tiny samples of the liquid and/or the gas phase that was present during formation, although in some cases they may have undergone significant changes from the original material. Studies of the current composition of the inclusions provide data on both the original composition and the change since trapping. These inclusions are seldom larger than 1 millimeter in diameter. The composition varies from a single major compound (e.g., water) in a single phase to a very complex mixture in one or more phases. The concentration of some of the compounds present may be at trace levels. We present here some analyses of inclusions in a variety of geological samples, including diamonds. We used a sample crusher and a gas chromatography-mass spectrometry (GC-MS) system to analyze for organic and inorganic volatiles present as major to trace constituents in inclusions. The crusher is a hardened stainless-steel piston cylinder apparatus with tungsten carbide crusing surfaces, and is operated in a pure helium atmosphere at a controlled temperature. Samples ranging from 1 mg to 1 g were crushed and the released volatiles were analyzed using multi-chromatographic columns and detectors, including the sensitive helium ionization detector. Identification of the GC peaks was carried out by GC-MS. This combination of procedures has been shown to provide geochemically useful information on the process involved in the history of the samples analyzed. ?? 1984.

Andrawes, F.; Holzer, G.; Roedder, E.; Gibson, E.K., Jr.; Oro, J.

1984-01-01

302

Volatile Emissions from Compressed Tissue  

PubMed Central

Since almost every fifth patient treated in hospital care develops pressure ulcers, early identification of risk is important. A non-invasive method for the elucidation of endogenous biomarkers related to pressure ulcers could be an excellent tool for this purpose. We therefore found it of interest to determine if there is a difference in the emissions of volatiles from compressed and uncompressed tissue. The ultimate goal is to find a non-invasive method to obtain an early warning for the risk of developing pressure ulcers for bed-ridden persons. Chemical analysis of the emissions, collected in compresses, was made with gas-chromatography – mass spectrometry and with a chemical sensor array, the so called electronic nose. It was found that the emissions from healthy and hospitalized persons differed significantly irrespective of the site. Within each group there was a clear difference between the compressed and uncompressed site. Peaks that could be certainly deemed as markers of the compression were, however, not identified. Nonetheless, different compounds connected to the application of local mechanical pressure were found. The results obtained with GC-MS reveal the complexity of VOC composition, thus an array of non-selective chemical sensors seems to be a suitable choice for the analysis of skin emission from compressed tissues; it may represent a practical instrument for bed side diagnostics. Results show that the adopted electronic noses are likely sensitive to the total amount of the emission rather than to its composition. The development of a gas sensor-based device requires then the design of sensor receptors adequate to detect the VOCs bouquet typical of pressure. This preliminary experiment evidences the necessity of studies where each given person is followed for a long time in a ward in order to detect the insurgence of specific VOCs pattern changes signalling the occurrence of ulcers. PMID:23874929

Dini, Francesca; Capuano, Rosamaria; Strand, Tillan; Ek, Anna-Christina; Lindgren, Margareta; Paolesse, Roberto; Di Natale, Corrado; Lundstrom, Ingemar

2013-01-01

303

The effect of chemical dispersants on the solution of volatile liquid hydrocarbons from spilled crude oil  

E-print Network

THE EFFECT OF CHEMICAL DISPERSANTS ON THE SOLUTION OF VOLATILE LIQUID HYDROCARBONS FROM SPILLED CRUDE OIL A Thesis by THOMAS JOSEPH McDONALD Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement... for the degree of MASTER OF SCIENCE August 1982 Major Subject: Oceanography THE EFFECT OF CHEMICAL DISPERSANTS ON THE SOLUTION OF VOLATILE LIQUID HYDROCARBONS FROM SPILLED CRUDE OIL A Thesis by THOMAS JOSEPH McDONALD Approved as to style and content by...

McDonald, Thomas Joseph

2012-06-07

304

Citrus essential oil of Nigeria. Part V: Volatile constituents of sweet orange leaf oil (Citrus sinensis).  

PubMed

The volatile oils extracted from leaves of eight cultivars of Citrus sinensis (L) Osbeck were comprehensively analysed by a combination of GC and GC-MS. Fifty four constituents accounting for 82.3-98.2% were identified. Sabinene (20.9-49.1%), delta-3-carene (0.3-14.3%), (E)-beta-ocimene (4.4-12.6%), linalool (3.7-11.1%) and terpinen-4-ol (1.7-12.5%) were the major constituents that are common to all the volatile oils. In addition, a cluster analysis was carried out and indicated at least four different chemotypes for the C. sinensis cultivars. PMID:21815430

Kasali, Adeleke A; Lawal, Oladipupo A; Eshilokun, Adeolu O; Olaniyan, Abayomi A; Opoku, Andy R; Setzer, William N

2011-06-01

305

Influence of the nature of the surface of polypyrrole films upon their interaction with volatile organic compounds  

Microsoft Academic Search

Although conducting polymers have been increasingly used in sensing devices to assess the quality of food and beverages, at present the details of the interaction mechanism between volatile organic compounds (VOCs) and the polymeric films used are not completely understood. In this work we examine how the sensitivity of polypyrrole films doped with different counter-ions (metanesulfonic acid sodium salt, octanesulfonic

C. P. de Melo; B. B. Neto; L. F. B. Lira; J. E. G. de Souza

2005-01-01

306

Proton Transfer Rate Coefficient Measurements of Selected Volatile Organic Molecules  

NASA Astrophysics Data System (ADS)

We have developed an apparatus based on the selected ion flow tube (SIFT)footnote D. Smith and N.G. Adams, Ads. At. Mol. Phys. 24, 1 (1987). that allows the study of proton transfer between various positive ions and volatile organic molecules. Reactions in the flow tube occur at pressures of approximately 300 mTorr, eliminating the requirement of thermal beam production. The proton donor molecule H_3O^+ has been produced using several types of electrical discharges in water vapor, such as a capacitively coupled RF discharge and a DC hollow cathode discharge. Presently we are developing an Asmussen-type microwave cavity discharge using the components of a standard microwave oven that has the advantages of simple design and operation, as well as low cost. We will be presenting the results of the microwave cavity ion source to produce H_3O^+, and compare it to the other studied sources. In addition, we will be presenting a preliminary measurement of the proton transfer rate coefficient in the reaction of H_3O^+ with acetone and methanol.

Brooke, G.; Popovi?, S.; Vuškovi?, L.

2002-05-01

307

Major Rock Groups  

NSDL National Science Digital Library

This resource from the University of Saskatchewan contains general information on the major rock groups: igneous, metamorphic and sedimentary. Describes the rock cycle and the properties and formation of each major rock group.

2008-08-21

308

EDITORIAL: Non-volatile memory based on nanostructures Non-volatile memory based on nanostructures  

NASA Astrophysics Data System (ADS)

Non-volatile memory refers to the crucial ability of computers to store information once the power source has been removed. Traditionally this has been achieved through flash, magnetic computer storage and optical discs, and in the case of very early computers paper tape and punched cards. While computers have advanced considerably from paper and punched card memory devices, there are still limits to current non-volatile memory devices that restrict them to use as secondary storage from which data must be loaded and carefully saved when power is shut off. Denser, faster, low-energy non-volatile memory is highly desired and nanostructures are the critical enabler. This special issue on non-volatile memory based on nanostructures describes some of the new physics and technology that may revolutionise future computers. Phase change random access memory, which exploits the reversible phase change between crystalline and amorphous states, also holds potential for future memory devices. The chalcogenide Ge2Sb2Te5 (GST) is a promising material in this field because it combines a high activation energy for crystallization and a relatively low crystallization temperature, as well as a low melting temperature and low conductivity, which accommodates localized heating. Doping is often used to lower the current required to activate the phase change or 'reset' GST but this often aggravates other problems. Now researchers in Korea report in-depth studies of SiO2-doped GST and identify ways of optimising the material's properties for phase-change random access memory [1]. Resistance switching is an area that has attracted a particularly high level of interest for non-volatile memory technology, and a great deal of research has focused on the potential of TiO2 as a model system in this respect. Researchers at HP labs in the US have made notable progress in this field, and among the work reported in this special issue they describe means to control the switch resistance and show that limiting the current during electroforming leads to the coexistence of two resistance switching modes in TiO2 memristive devices [2]. They also present spectromicroscopic observations and modelling results for the Joule heating during switching, providing insights into the ON/OFF switching process [3]. Researchers in Korea have examined in detail the mechanism of electronic bipolar resistance switching in the Pt/TiO2/Pt structure and show that degradation in switching performance of this system can be explained by the modified distribution of trap densities [4]. The issue also includes studies of TiO2 that demonstrate analog memory, synaptic plasticity, and spike-timing-dependent plasticity functions, work that contributes to the development of neuromorphic devices that have high efficiency and low power consumption [5]. In addition to enabling a wide range of data storage and logic applications, electroresistive non-volatile memories invite us to re-evaluate the long-held paradigms in the condensed matter physics of oxides. In the past three years, much attention has been attracted to polarization-mediated electronic transport [6, 7] and domain wall conduction [8] as the key to the next generation of electronic and spintronic devices based on ferroelectric tunnelling barriers. Typically local probe experiments are performed on an ambient scanning probe microscope platform under conditions of high voltage stresses, conditions highly conducive to electrochemical reactions. Recent experiments [9-13] suggest that ionic motion can heavily contribute to the measured responses and compete with purely physical mechanisms. Electrochemical effects can also be expected in non-ferroelectric materials such as manganites and cobaltites, as well as for thick ferroelectrics under high-field conditions, as in capacitors and tunnelling junctions where the ionic motion could be a major contributor to electric field-induced strain. Such strain, in turn, can affect the effective barrier width in tunnelling experiments, resulting in memristive ionic switching. These phenomena mu

Kalinin, Sergei; Yang, J. Joshua; Demming, Anna

2011-06-01

309

The Age of Majority.  

ERIC Educational Resources Information Center

During the past 2 years state laws lowering the age of majority to 18 and other statutes that confer some majority rights on minors have considerably altered the status of young people in our society. In 7 states, the age of majority has been lowered in an effort to relieve young people of the minority disabilities originally intended to protect…

Council of State Governments, Lexington, KY.

310

A study of the reactions of H3O+, NO+ and O2+ ions with nine alkoxy alcohols.  

PubMed

Following a selected ion flow tube mass spectrometry (SIFT-MS), analysis of the headspace of a commercial available nail polish remover pad in which gamma-butyrolactone (GBL) and 2-butoxy-1-ethanol were found to be the major volatiles, a study of the reactions of H3O+, NO+ and O2+* ions with nine alkoxy alcohols (R1-O-R2OH) was carried out using selected ion flow tube (SIFT) at a carrier gas (helium) pressure of 9. 3 x 10(1) Pa. Experiments were also performed at various carrier gas pressures (4 x 10(1)-1.1 x 10(2) Pa) for some reactions and under moist air condition. The number and distribution of the hydrates for the product ions were used to identify their structures and to investigate reaction mechanisms. The H3O+ reactions proceed via nascent ion-molecule complex (H3O+ .M)*, then produce R1-O-R2OH. H+, ( R1-O-R2)+, HOR2OH. H+ and R2=O. H+ ions through various channels. Similarly, via a nascent complex (NO+.M)*, NO+. M, (M-H)+ and (M-ROH)+ ions were produced in the NO+ reactions. The collisions between the nascent complexes (H3O+ .M)* and (NO+.M)* with a third body (He, N2 and O2 etc) have influence on the product ion distributions. The O2+ reactions produce mainly dissociative product ions and it is uncertain whether they proceed via the nascent ion-molecule complex (O2+ . M)*. This study provides rate coefficients and product ions in the SIFT-MS database for the analysis of these compounds in normal and humid air samples. It will be further utilised into addiction and drug abuse, respiratory medicine and other research areas using SIFT-MS. PMID:16836154

Wang, Tianshu

2006-04-01

311

Analysis and sensory evaluation of gooseberry (Ribes uva crispa L.) volatiles.  

PubMed

Volatiles of gooseberries (Ribes uva cripsa L.) were isolated by means of vacuum-headspace-extraction, and the obtained concentrates were analyzed via capillary gas chromatography-mass spectrometry. To ensure the quantitation of highly volatile compounds, headspace analysis was additionally performed on selected batches. C?-components (e.g., (Z)-hex-3-enal, (E)-hex-2-enal), derived from lipid oxidation, and short-chain esters (e.g., ethyl acetate, methyl butanoate, ethyl butanoate) turned out to be the major compound classes in the fresh fruit. The compositional variability was demonstrated by analyzing several gooseberry varieties at different stages of ripeness. The contributions of volatiles to the gooseberry aroma were assessed by using gas chromatography-olfactometry in combination with aroma extract dilution analysis and calculation of odor activity values. C?-components and esters were shown to be responsible for the green and fruity character of fresh gooseberries. PMID:23721163

Hempfling, Katrin; Fastowski, Oxana; Kopp, Markus; Nikfardjam, Martin Pour; Engel, Karl-Heinz

2013-07-01

312

Different isolation methods for determination of composition of volatiles from Nigella damascena L. seeds.  

PubMed

Volatile organic compounds (VOCs) from seeds of Nigella damascena L. were isolated using different techniques. The yield, as well as the qualitative and quantitative composition of the oils, was strongly influenced by the isolation method. In the hydrodistilled essential oil, the major components were the sesquiterpene hydrocarbons beta-elemene (59.1%), beta-selinene (12.8%) and alpha-selinene (12.6%). Conventional solvent extraction, followed by hydrodistillation, resulted in a volatile oil with a different composition than that of the hydrodistilled oil. The extracted oils predominantly contained sesquiterpene hydrocarbons, but also methyl anthranilate derivatives. By means of HS-SPME, it was possible to analyze not only sesquiterpenes and anthranilates, but also monoterpenes and the most volatile compounds, for example, the lower fatty acid (butyric, capronic) esters, which determine the characteristic sweet scent of N. damascena seeds. Using all testing methods, 55 compounds were identified, 40 of which are new for N. damascena seed VOCs. PMID:19967995

Wajs, Anna; Bonikowski, Radoslaw; Kalemba, Danuta

2009-11-01

313

Highly volatile constituents of Vetiveria zizanioides roots grown under different cultivation conditions.  

PubMed

Roots of Vetiveria zizanioides Nash (Mae Hae; Thai ecotype) planted in three different cultivation systems (normal soil, normal soil with added microbes and semi- hydroponically) were extracted using a simultaneous steam distillation and solvent extraction (SDE) apparatus. Yields of the essential oils obtained were 0.27, 0.18 and 0.06%, respectively. The separation profiles obtained by comprehensive two-dimensional gas chromatography (GCxGC) and solid phase microextraction (SPME)-GCxGC analyses of the crude essential oils showed a total of 156 and 48 well-resolved components, respectively. The highly volatile fractions isolated from the three essential oils by SPME were subjected to analysis by GC-MS and 42 compounds were identified in total. Volatile component profiles of the oils obtained by normal soil and semi-hydroponic cultivation were similar, whereas a quantitative difference was noted in some major volatiles when the cultivation system containing microbes was utilized. PMID:17971758

Pripdeevech, Patcharee; Wongpornchai, Sugunya; Promsiri, Ampan

2006-01-01

314

Analysis of roasted and unroasted Pistacia terebinthus volatiles using direct thermal desorption-GCxGC-TOF/MS.  

PubMed

The objective of this study was to determine the effects of roasting time on volatile components of Pistacia terebinthus L., a fruit growing wild in Turkey. The whole fruit samples were pan roasted for 0, 5, 10, 15, 20 and 25min at 200°C. Volatile compounds were isolated and identified using the direct thermal desorption (DTD) method coupled with comprehensive gas chromatography - time of flight mass spectrometry (GCxGC-TOF/MS). The major components of the fresh hull of P. terebinthus were ?-pinene (10.37%), limonene (8.93%), ?-pinene (5.53%), 2-carene (4.47%) and ?-muurolene (4.29%). Eighty-three constituents were characterised from the volatiles of fresh whole P. terebinthus fruits obtained by direct thermal desorption with ?-pinene (9.62%), limonene (5.54%), ?-cadinane (5.48%), ?-pinene (5.46%), ?-caryophyllene (5.24%) being the major constituents. The type and the number of constituents characterised were observed to change with differing roasting times. Limonene (5.56%), ?-pinene (4.84%), 5-methylfurfural (4.78%), 5-hydroxymethylfurfural (5-HMF, 3.89%), dimethylmetoxyfuranone (3.67%) and 3-methyl-2(5H)furanone (3.12%) were identified as the major components among the 104 compounds characterised in the volatiles of P. terebinthus, roasted for 25min. In addition, volatiles of fully roasted P. terebinthus fruits contained furans and furanones (15.42%), pyridines (4.45%) and benzene derivatives (3.81%) as the major groups. PMID:25212365

Gogus, F; Ozel, M Z; Kocak, D; Hamilton, J F; Lewis, A C

2011-12-01

315

The volatile metabolome of grapevine roots: First insights into the metabolic response upon phylloxera attack  

PubMed Central

Many plant species respond to herbivore attack by an increased formation of volatile organic compounds. In this preliminary study we analysed the volatile metabolome of grapevine roots [Teleki 5C (Vitis berlandieri Planch. × Vitis riparia Michx.)] with the aim to gain insight into the interaction between phylloxera (Daktulosphaira vitifoliae Fitch; Hemiptera: Phylloxeridae) and grapevine roots. In the first part of the study, headspace solid phase microextraction (HS-SPME) coupled to gas chromatography – mass spectrometry (GC–MS) was used to detect and identify volatile metabolites in uninfested and phylloxera-infested root tips of the grapevine rootstock Teleki 5C. Based on the comparison of deconvoluted mass spectra with spectra databases as well as experimentally derived retention indices with literature values, 38 metabolites were identified, which belong to the major classes of plant volatiles including C6-compounds, terpenes (including modified terpenes), aromatic compounds, alcohols and n-alkanes. Based on these identified metabolites, changes in root volatiles were investigated and resulted in metabolite profiles caused by phylloxera infestation. Our preliminary data indicate that defence related pathways such as the mevalonate and/or alternative isopentenyl pyrophosphate-, the lipoxygenase- (LOX) as well as the phenylpropanoid pathway are affected in root galls as a response to phylloxera attack. PMID:21764593

Lawo, Nora C.; Weingart, Georg J.F.; Schuhmacher, Rainer; Forneck, Astrid

2011-01-01

316

Contemporaneous aggregation and long-memory property of returns and volatility in the Korean stock market  

NASA Astrophysics Data System (ADS)

The principal objective of this study is to determine whether the long-memory property is real or a spurious result caused by contemporaneous aggregation. In order to assess the presence of long memory in returns and volatility, two different long-memory detection techniques (modified R/S analysis and the GPH test) were applied to the KOSPI 50 index and its 50 constituent individual stock prices. According to the empirical evidence gleaned from the two long-memory tests, we conclude that there exists significant evidence for the long-memory property in volatility in both the market index and in a majority of individual stocks. These findings indicate that the observed evidence of the long-memory feature in volatility of index series is not spurious, and that we can reject the hypothesis that spurious long-memory evidence in the volatility of index series is the consequence of contemporaneous aggregation. However, this conclusion should be considered cautiously, given that a considerable number of the individual stock volatilities in square returns strongly show a short-memory property, as the level of significance in statistical decisions is lowered to the 1% level.

Kang, Sang Hoon; Cheong, Chongcheul; Yoon, Seong-Min

2010-11-01

317

Trophic Complexity and the Adaptive Value of Damage-Induced Plant Volatiles  

PubMed Central

Indirect plant defenses are those facilitating the action of carnivores in ridding plants of their herbivorous consumers, as opposed to directly poisoning or repelling them. Of the numerous and diverse indirect defensive strategies employed by plants, inducible volatile production has garnered the most fascination among plant-insect ecologists. These volatile chemicals are emitted in response to feeding by herbivorous arthropods and serve to guide predators and parasitic wasps to their prey. Implicit in virtually all discussions of plant volatile-carnivore interactions is the premise that plants “call for help” to bodyguards that serve to boost plant fitness by limiting herbivore damage. This, by necessity, assumes a three-trophic level food chain where carnivores benefit plants, a theoretical framework that is conceptually tractable and convenient, but poorly depicts the complexity of food-web dynamics occurring in real communities. Recent work suggests that hyperparasitoids, top consumers acting from the fourth trophic level, exploit the same plant volatile cues used by third trophic level carnivores. Further, hyperparasitoids shift their foraging preferences, specifically cueing in to the odor profile of a plant being damaged by a parasitized herbivore that contains their host compared with damage from an unparasitized herbivore. If this outcome is broadly representative of plant-insect food webs at large, it suggests that damage-induced volatiles may not always be beneficial to plants with major implications for the evolution of anti-herbivore defense and manipulating plant traits to improve biological control in agricultural crops. PMID:23209381

Kaplan, Ian

2012-01-01

318

In situ microbial volatilization of selenium in soils: A case history  

SciTech Connect

A pilot-scale field experiment has been conducted since 1990 to test the effectiveness of microbial volatilization in removing selenium (Se) from soils contaminated with agricultural drainage water. The experiment, in which only irrigation and aeration were employed to enhance microbial processes, was designed to measure all major Se fluxes, including not only selenium loss via volatilization, but also advection with infiltrating rainwater, evapotranspirative transport, and plant uptake. The goal was to account for the total Se mass balance and address questions as to the significance of microbial volatilization relative to other fluxes. Although data collected from 1990 to 1994 showed decreases of Se concentrations in the top soil, subsequent data demonstrated that advective Se fluxes due to rainwater infiltration and evapotranspiration are largely responsible for the observed changes. Se volatilization was measured to account for an annual loss of only about 1%, with volatilization rates decreasing significantly with time, presumably due to the depletion of soil organic carbon. The integrated results of this project demonstrate the advantages and even necessity of an inter-disciplinary and multi-phase approach to evaluating the effectiveness of bioremediation strategies. Extreme caution needs to be taken in interpreting early results; long-term data collection and follow-up are indispensable.

Zawislanski, Peter T.; Benson, Sally M.; Jayaweera, Gamani R.; Wu, L.; Frankenberger, William T.

1999-01-02

319

Volatile-bearing phases in carbonaceous chondrites: Compositions, modal abundance, and reaction kinetics  

NASA Technical Reports Server (NTRS)

The spectral and density characteristics of Phobos and Deimos (the two small natural satellites of Mars) strongly suggest that a significant fraction of the near-earth asteroids are made of carbonaceous chondrites, which are rich in volatile components and, thus, could serve as potential resources for propellants and life supporting systems in future planetary missions. However, in order to develop energy efficient engineering designs for the extraction of volatiles, knowledge of the nature and modal abundance of the minerals in which the volatiles are structurally bound and appropriate kinetic data on the rates of the devolatilization reactions is required. Theoretical calculations to predict the modal abundances and compositions of the major volatile-bearing and other mineral phases that could develop in the bulk compositions of C1 and C2 classes (the most volatile rich classes among the carbonaceous chondrites) were performed as functions of pressure and temperature. The rates of dehydration of talc at 585, 600, 637, and 670 C at P(total) = 1 bar were determine for the reaction: Talc = 3 enstatite + quartz + water. A scanning electron microscopic study was conducted to see if the relative abundance of phases can be determined on the basis of the spectral identification and x ray mapping. The results of this study and the other studies within the project are discussed.

Ganguly, Jibamitra

1990-01-01

320

Potential Signatures of Semi-volatile Compounds Associated With Nuclear Processing  

SciTech Connect

Semi-volatile chemicals associated with nuclear processes (e.g., the reprocessing of uranium to produce plutonium for nuclear weapons, or the separation of actinides from processing waste streams), can provide sticky residues or signatures that will attach to piping, ducting, soil, water, or other surface media. Volatile compounds, that are more suitable for electro-optical sensing, have been well studied. However, the semi-volatile compounds have not been well documented or studied. A majority of these semi-volatile chemicals are more robust than typical gaseous or liquid chemicals and can have lifetimes of several weeks, months, or years in the environment. However, large data gaps exist concerning these potential signature compounds and more research is needed to fill these data gaps so that important signature information is not overlooked or discarded. This report investigates key semi-volatile compounds associated with nuclear separations, identifies available chemical and physical properties, and discusses the degradation products that would result from hydrolysis, radiolysis and oxidation reactions on these compounds.

Probasco, Kathleen M.; Birnbaum, Jerome C.; Maughan, A. D.

2002-06-01

321

Olfactory responses of banana weevil predators to volatiles from banana pseudostem tissue and synthetic pheromone.  

PubMed

As a response to attack by herbivores, plants can emit a variety of volatile substances that attract natural enemies of these insect pests. Predators of the banana weevil, Cosmopolites sordidus (Germar) (Coleoptera: Curculionidae) such as Dactylosternum abdominale (Coleoptera: Hydrophilidae) and Pheidole megacephala (Hymenoptera: Formicidae), are normally found in association with weevil-infested rotten pseudostems and harvested stumps. We investigated whether these predators are attracted to such environments in response to volatiles produced by the host plant, by the weevil, or by the weevil plant complex. We evaluated predator responses towards volatiles from banana pseudostem tissue (synomones) and the synthetic banana weevil aggregation pheromone Cosmolure+ in a two-choice olfactometer. The beetle D. abdominale was attracted to fermenting banana pseudostem tissue and Cosmolure+, whereas the ant P. megacephala was attracted only to fermented pseudostem tissue. Both predators were attracted to banana pseudostem tissue that had been damaged by weevil larvae irrespective of weevil presence. Adding pheromone did not enhance predator response to volatiles from pseudostem tissue fed on by weevils. The numbers of both predators recovered with pseudostem traps in the field from banana mats with a pheromone trap were similar to those in pseudostem traps at different distance ranges from the pheromone. Our study shows that the generalist predators D. abdominale and P. megacephala use volatiles from fermented banana pseudostem tissue as the major chemical cue when searching for prey. PMID:16222791

Tinzaara, W; Gold, C S; Dicke, M; van Huis, A

2005-07-01

322

Attraction of pea moth Cydia nigricana to pea flower volatiles.  

PubMed

The pea moth Cydia nigricana causes major crop losses in pea (Pisum sativum) production. We investigated attraction of C. nigricana females to synthetic pea flower volatiles in a wind tunnel and in the field. We performed electroantennogram analysis on 27 previously identified pea plant volatiles, which confirmed antennal responses to nine of the compounds identified in pea flowers. A dose-dependent response was found to eight of the compounds. Various blends of the nine pea flower volatiles eliciting antennal responses were subsequently studied in a wind tunnel. A four-compound blend comprising hexan-1-ol, (E)-2-hexen-1-ol, (Z)-?-ocimene and (E)-?-ocimene was equally attractive to mated C. nigricana females as the full pea flower mimic blend. We conducted wind-tunnel tests on different blends of these four pea flower compounds mixed with a headspace sample of non-flowering pea plants. By considering the effects of such green leaf background odour, we were able to identify (Z)- and (E)-?-ocimene as fundamental for host location by the pea moths, and hexan-1-ol and (E)-2-hexen-1-ol as being of secondary importance in that context. In the field, the two isomers of ?-ocimene resulted in trap catches similar to those obtained with the full pea flower mimic and the four-compound blend, which clearly demonstrated the prime significance of the ?-ocimenes as attractants of C. nigricana. The high level of the trap catches of female C. nigricana noted in this first field experiment gives a first indication of the potential use of such artificial kairomones in pea moth control. PMID:24508043

Thöming, Gunda; Knudsen, Geir K

2014-04-01

323

Knockout of the gene encoding the K(2P) channel KCNK7 does not alter volatile anesthetic sensitivity.  

PubMed

The molecular site of action for volatile anesthetics remains unknown despite many years of study. Members of the K(2P) potassium channel family, whose currents are potentiated by volatile anesthetics have emerged as possible anesthetic targets. In fact, a mouse model in which the gene for TREK-1 (KCNK2) has been inactivated shows resistance to volatile anesthetics. In this study we tested whether inactivation of another member of this ion channel family, KCNK7, in a knockout mouse displayed altered sensitivity to the anesthetizing effect of volatile anesthetics. KCNK7 knockout mice were produced by standard gene inactivation methods. Heterozygous breeding pairs produced animals that were homozygous, heterozygous or wild-type for the inactivated gene. Knockout animals were tested for movement in response to noxious stimulus (tail clamp) under varying concentrations of isoflurane, halothane, and desflurane to define the minimum alveolar concentration (MAC) preventing movement. Mice homozygous for inactivated KCNK7 were viable and indistinguishable in weight, general development and behavior from heterozygotes or wild-type littermates. Knockout mice (KCNK7-/-) displayed no difference in MAC for the three volatile anesthetics compared to heterozygous (+/-) or wild-type (+/+) littermates. Because inactivation of KCNK7 does not alter MAC, KCNK7 may play only a minor role in normal CNS function or may have had its function compensated for by other inhibitory mechanisms. Additional studies with transgenic animals will help define the overall role of the K(2P) channels in normal neurophysiology and in volatile anesthetic mechanisms. PMID:18572259

Yost, C Spencer; Oh, Irene; Eger, Edmond I; Sonner, James M

2008-11-21

324

Ion source  

DOEpatents

A magnetic filter for an ion source reduces the production of undesired ion species and improves the ion beam quality. High-energy ionizing electrons are confined by the magnetic filter to an ion source region, where the high-energy electrons ionize gas molecules. One embodiment of the magnetic filter uses permanent magnets oriented to establish a magnetic field transverse to the direction of travel of ions from the ion source region to the ion extraction region. In another embodiment, low energy 16 eV electrons are injected into the ion source to dissociate gas molecules and undesired ion species into desired ion species.

Leung, Ka-Ngo (Hercules, CA); Ehlers, Kenneth W. (Alamo, CA)

1984-01-01

325

Volatile Species Retention During Metallic Fuel Casting  

SciTech Connect

Metallic nuclear fuels are candidate transmutation fuel forms for advanced fuel cycles. Through the operation of the Experimental Breeder Reactor II metallic nuclear fuels have been shown to be robust and easily manufactured. However, concerns have been raised concerning loss of americium during the casting process because of its high vapor pressure. In order to address these concerns a gaseous diffusion model was developed and a series of experiments using both manganese and samarium as surrogates for americium were conducted. The modeling results showed that volatility losses can be controlled to essentially no losses with a modest overpressure. Experimental results also showed volatile species retention down to no detectable losses through overpressure, although the loss values varied from the model results the same trend was seen. Bases on these results it is very probably that americium losses through volatility can be controlled to no detectable losses through application of a modest overpressure during casting.

Randall S. Fielding; Douglas L. Proter

2013-10-01

326

Volatile species retention during metallic fuel casting  

NASA Astrophysics Data System (ADS)

Metallic nuclear fuels are candidate transmutation fuel forms for advanced fuel cycles. Through the operation of the Experimental Breeder Reactor II metallic nuclear fuels have been shown to be robust and easily manufactured. However, concerns have been raised concerning loss of americium during the casting process because of its high vapor pressure. In order to address these concerns a gaseous diffusion model was developed and a series of experiments using both manganese and samarium as surrogates for americium were conducted. The modeling results showed that volatility losses can be controlled to essentially no losses with a modest overpressure. Experimental results also showed volatile species retention down to no detectable losses through overpressure, and although the loss values varied from the model results the same trend was seen. Based on these results it is very probable that americium losses through volatility can be controlled to no detectable losses through application of a modest overpressure during casting.

Fielding, Randall S.; Porter, Douglas L.

2013-10-01

327

Catalyst for Oxidation of Volatile Organic Compounds  

NASA Technical Reports Server (NTRS)

Disclosed is a process for oxidizing volatile organic compounds to carbon dioxide and water with the minimal addition of energy. A mixture of the volatile organic compound and an oxidizing agent (e.g. ambient air containing the volatile organic compound) is exposed to a catalyst which includes a noble metal dispersed on a metal oxide which possesses more than one oxidation state. Especially good results are obtained when the noble metal is platinum, and the metal oxide which possesses more than one oxidation state is tin oxide. A promoter (i.e., a small amount of an oxide of a transition series metal) may be used in association with the tin oxide to provide very beneficial results.

Wood, George M. (Inventor); Upchurch, Billy T. (Inventor); Schryer, David R. (Inventor); Davis, Patricia P. (Inventor); Kielin, Erik J. (Inventor); Brown, Kenneth G. (Inventor); Schyryer, Jacqueline L. (Inventor); DAmbrosia, Christine M. (Inventor)

2000-01-01

328

Changes in dark chocolate volatiles during storage.  

PubMed

Chocolate storage is critical to the quality of the final product. Inadequate storage, especially with temperature fluctuations, may lead to a change in crystal structure, which may eventually cause fat bloom. Bloom is the main cause of quality loss in the chocolate industry. The impact of various storage conditions on the flavor quality of dark chocolate was determined. Dark chocolate was stored in different conditions leading to either fat or sugar bloom and analyzed at 0, 4, and 8 weeks of storage. Changes in chocolate flavor were determined by volatile analysis and descriptive sensory evaluation. Results were analyzed by analysis of variance (ANOVA), cluster analysis, principal component analysis (PCA), and linear partial least-squares regression analysis (PLS). Volatile concentration and loss were significantly affected by storage conditions. Chocolates stored at high temperature were the most visually and texturally compromised, but volatile concentrations were affected the least, whereas samples stored at ambient, frozen, and high relative humidity conditions had significant volatile loss during storage. It was determined that high-temperature storage caused a change in crystal state due to the polymorphic shift to form VI, leading to an increase in sample hardness. Decreased solid fat content (SFC) during high-temperature storage increased instrumentally determined volatile retention, although no difference was detected in chocolate flavor during sensory analysis, possibly due to instrumental and sensory sampling techniques. When all instrumental and sensory data had been taken into account, the storage condition that had the least impact on texture, surface roughness, grain size, lipid polymorphism, fat bloom formation, volatile concentrations, and sensory attributes was storage at constant temperature and 75% relative humidity. PMID:22482444

Nightingale, Lia M; Cadwallader, Keith R; Engeseth, Nicki J

2012-05-01

329

Volatilization of EPTC: Simulation and measurement  

SciTech Connect

Many of the organic chemicals used in agricultural production are susceptible to loss from the soil surface to the atmosphere by volatilization. Adequate prediction of the impact of these chemicals on the environment thus requires consideration of both downward movement through the soil to groundwater and upward movement in the gas phase to the atmosphere. We developed a method to mechanistically simulate volatilization within the framework of a conventionally formulated solute transport model and used it to simulate the gas-phase losses of EPTC, a commonly used volatile herbicide. The model considers efflux of a trace gas at the sod surface to be a process of unsteady diffusion, interrupted intermittently by dispersive events that can be thought of as eddies at the innermost scale. Model results were compared to measurements of volatilization during the first 7 d following application of EPTC, conducted with a Bowen ratio system in a 17-ha field at Rosemount, MN. The measurements indicated a relatively large initial flux (ca. 150 g ha{sup -1} h{sup -1}) that rapidly decreased to negligible levels within a day following application. The model agreed reasonably well on the first day, if a measured value for Henry`s constant was used rather than a value estimated from the saturation vapor pressure and the solubility. However, on subsequent days the model considerably overestimated volatilization, regardless of the Henry`s constant that was used. It is likely that hysteresis in sorption/desorption, particularly as surface soil dries following herbicide incorporation, may be the primary reason why volatile losses are lower than might be predicted on the basis of equilibrium partitioning theory. 42 refs., 5 figs., 1 tab.

Baker, J.M.; Koskinen, W.C.; Dowdy, R.H. [Univ. of Minnesota, St. Paul, MN (United States)

1996-01-01

330

Characterization of volatile compounds in Astraeus spp.  

PubMed

Astraeus spp. is consumed in several regions of Southeast Asia. C(8) compounds, including 1-octen-3-ol, are the main volatile compounds in fresh Astraeus spp. Other compounds typical of edible mushrooms, such as terpenoids and sulfur-containing compounds, were not detected in fresh Astraeus spp. The amounts of fatty acids, including linoleic acid, substantially decreased after homogenization of fresh Astraeus spp. This high metabolic activity possibly correlates with formation of the C(8) volatiles. Heating the mushrooms produced cyclohexene compounds, 2-n-pentyl-furan, furanyl compounds, and benzaldehyde. PMID:19966456

Kakumyan, Pattana; Matsui, Kenji

2009-12-01

331

The Relationship between Major Life Events and the Potential for Child Abuse.  

ERIC Educational Resources Information Center

High risk parenting and child abuse are the consequences of multiple and interactive factors. The occurrence of major life events such as death, divorce, marriage, and pregnancy frequently presents stressors that may ignite an already volatile family situation. This study was conducted to examine the incidence of reported major life events in…

Burdsal, Jeanne

332

Ion-ion neutralization  

NASA Astrophysics Data System (ADS)

A variable-temperature FALP/SIFT apparatus has been built which combines the essential features of the versatile Flowing Afterglow/Langmuir Probe (FALP) and Selected Ion Flow Tube (SIFT) apparatuses. It has been used to determine the coefficients for the recombination reactions of NO+ and 02+ ions with electrons over the temperature range 200-600 K and for the attachment reactions of SF6, CC14 and C12 with electrons at 300 K. The results of these studies are reported and are shown to resolve some of the differences which are apparent between the result of previous studies of some of these reactions. A reassessment, based on laboratory data, of the ion-ion recombination coefficients appropriate to the stratosphere is also presented and the new values are in good agreement with those derived from in-situ stratospheric observations by other workers.

Smith, D.; Adams, N. G.

1982-05-01

333

Volatile organic compounds from a Tuber melanosporum fermentation system.  

PubMed

A total of 59 volatile organic compounds (VOCs) were identified from Tuber melanosporum fermentation: 53 from its fermented mycelia and 32 from the fermentation broth. Alcohol-derived compounds were predominant in both the fermentation mycelia and the broth, although long chain fatty acids and isoprenoids were, for the first time, also found in the mycelia. The intense wine bouquet properties of the broth arose from several specific flavor substances, including sulfur compounds, pyrazines, furans and jasmones. Comparing the VOCs identified in this work with those previously reported, our results are more similar to the composition of the Tuber fruiting-body than previous Tuber fermentations. The composition and accumulation of flavor volatiles (e.g., pyrazines, sulfur compounds, and esters) and major constituents (e.g., 3-methyl-1-butanol and 2-phenylethanol) in this fermentation were significantly influenced by the sucrose concentration in the medium. The obtained information could therefore be useful in applications to convert the flavors of truffle mycelia similar to those of the fruiting-body by optimising the fermentation process. PMID:22980851

Li, Yuan-Yuan; Wang, Guan; Li, Hong-Mei; Zhong, Jian-Jiang; Tang, Ya-Jie

2012-12-15

334

Glycosidically bound volatiles and flavor precursors in Laurus nobilis L.  

PubMed

Glycosidically bound volatile compounds in different parts (leaves and buds) of Laurus nobilis L. were investigated. After isolation of extracts obtained by Amberlite XAD-2 adsorption and methanol elution, glycosides were analyzed after enzymatic hydrolysis by GC-MS or directly after trifluoroacetyl (TFA) derivatization by GC-MS in EI and NCI mode. In the leaves most of the glycosidically bound volatiles occur as beta-D-glucopyranosides. Among the disaccharides, primeverosides are predominant; smaller amounts of alpha-L-arabinofuranosyl-beta-D-glucopyranosides, rutinosides, and vicianocides could also be identified. Major aglycons comprised benzyl alcohol, some linalool-diols, 2-hydroxy-1,8-cineole and its derivatives such as 2,3-dehydro-1,8-cineole, sobrerols, and menthadien-8-ols. Among the identified nor-carotenoids, 3-oxo-alpha-ionol, the corresponding 7,8-dihydro derivative, and vomifoliol are predominant in leaves. 3-Hydroxy-beta-damascone and 3-hydroxy-7,8-didehydro-beta-ionol, precursors of the sensorially active damascenone, were identified only in the buds. PMID:15769161

Kilic, Ayben; Kollmannsberger, Hubert; Nitz, Siegfried

2005-03-23

335

Fatty Acid and Volatile Oil Compositions of Allomyrina dichotoma Larvae  

PubMed Central

Thirty-two different volatile oils were identified from Allomyrina dichotoma (A. dichotoma) larvae by gas chromatography/mass spectrometry (GC/MS). The major volatile components were 2,2,4-trimethyl-3-carboxyisopropyl pentanoic acid isobutyl ester (5.83%), phenol,2,6-bis(a,a-dimethyl ethyl)-4-(1-methyl-1-phenylethyl) (5.72%), heptacosane (5.49%) and phenol,2,4-bis(1-methyl-1-phenylethyl) (5.47%). The composition of the fatty acids in A. dichotoma larvae was also determined by gas chromatography (GC) and fourteen constituents were identified. Oleic acid (19.13%) was the most abundant fatty acid followed by palmitic acid (12.52%), palmitoleic acid (3.71%) and linoleic acid (2.08%) in 100 g of A. dichotoma larvae on a dry weight basis. The quantity of unsaturated fatty acids (64.00%) were higher than that of saturated ones (36.00%). The predominant fatty acids in A. dichotoma consist of monounsaturated fatty acid (MUFA, 57.70%) such as oleic acid, myristoleic acid and palmitoleic acid, followed by saturated fatty acids (36.00%) and polyunsaturated fatty acids (PUFA, 6.50%). In particular, the presence of essential fatty acids, such as linoleic (5.30%) and linolenic acid (0.40%) give A. dichotoma larvae considerable nutritional and functional value and it may be a useful source for food and/or industrial utilization. PMID:24471102

Youn, Kumju; Kim, Ji-Young; Yeo, Hyelim; Yun, Eun-Young; Hwang, Jae-Sam; Jun, Mira

2012-01-01

336

Volatiles of Curcuma mangga Val. & Zijp (Zingiberaceae) from Malaysia.  

PubMed

Analysis by GC and GC/MS of the essential oil obtained from Malaysian Curcuma mangga Val. & Zijp (Zingiberaceae) rhizomes allowed the identification of 97 constituents, comprising 89.5% of the total oil composition. The major compounds were identified as myrcene (1; 46.5%) and ?-pinene (2; 14.6%). The chemical composition of this and additional 13 oils obtained from selected Curcuma L. taxa were compared using multivariate statistical analyses (agglomerative hierarchical cluster analysis and principal component analysis). The results of the statistical analyses of this particular data set pointed out that 1 could be potentially used as a valuable infrageneric chemotaxonomical marker for C. mangga. Moreover, it seems that C. mangga, C. xanthorrhiza Roxb., and C. longa L. are, with respect to the volatile secondary metabolites, closely related. In addition, comparison of the essential oil profiles revealed a potential influence of the environmental (geographical) factors, alongside with the genetic ones, on the production of volatile secondary metabolites in Curcuma taxa. PMID:22083913

Wahab, Ikarastika Rahayu Abdul; Blagojevi?, Polina D; Radulovi?, Niko S; Boylan, Fabio

2011-11-01

337

Analysis of volatile organic compounds. [trace amounts of organic volatiles in gas samples  

NASA Technical Reports Server (NTRS)

An apparatus and method are described for reproducibly analyzing trace amounts of a large number of organic volatiles existing in a gas sample. Direct injection of the trapped volatiles into a cryogenic percolum provides a sharply defined plug. Applications of the method include: (1) analyzing the headspace gas of body fluids and comparing a profile of the organic volatiles with standard profiles for the detection and monitoring of disease; (2) analyzing the headspace gas of foods and beverages and comparing the profile with standard profiles to monitor and control flavor and aroma; and (3) analyses for determining the organic pollutants in air or water samples.

Zlatkis, A. (inventor)

1977-01-01

338

Volatile pheromone signalling in Drosophila  

PubMed Central

Once captured by the antenna, 11-cis vaccenyl acetate (cVA) binds to an extracellular binding protein called LUSH that undergoes a conformational shift upon cVA binding. The stable LUSH–cVA complex is the activating ligand for pheromone receptors present on the dendrites of the aT1 neurones, comprising the only neurones that detect cVA pheromone. This mechanism explains the single molecule sensitivity of insect pheromone detection systems. The receptor that recognizes activated LUSH consists of a complex of several proteins, including Or67d, a member of the tuning odourant receptor family, Orco, a co-receptor ion channel, and SNMP, a CD36 homologue that may be an inhibitory subunit. In addition, genetic screens and reconstitution experiments reveal additional factors that are important for pheromone detection. Identification and functional dissection of these factors in Drosophila melanogaster Meigen should permit the identification of homologous factors in pathogenic insects and agricultural pests, which, in turn, may be viable candidates for novel classes of compounds to control populations of target insect species without impacting beneficial species. PMID:24347807

Smith, Dean P.

2013-01-01

339

Music Majors ADVISING & REGISTRATION  

E-print Network

Music Majors ADVISING & REGISTRATION INFORMATION For any student looking to pursue a degree within the Department of Music please visit the following website for additional program information: http://www.fau.edu/music/ Advising and Registration Information: As a music major you will need to complete OARS as OARS provides

Fernandez, Eduardo

340

Thalassaemia major in Deutschland  

Microsoft Academic Search

Zusammenfassung Thalassaemia minor tritt sporadisch in der Bevölkerung Deutschlands auf. 1941 wurde auf Grund klinischer Befunde der erste Fall von Thalassaemia major bei einem deutschen Patienten beschrieben. In der vorliegenden Arbeit wird über ein deutsches, aus dem Westerwald stammendes Kind berichtet, bei dem die Diagnose einer Thalassaemia major durch Hämoglobinelektrophorese und Bestimmung des alkali-resistenten Hämoglobins gesichert werden konnte.

G. Flatz; H. Hauke; E. Kleihauer

1964-01-01

341

40 CFR 60.602 - Standard for volatile organic compounds.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Standard for volatile organic compounds. 60.602 Section 60...Standards of Performance for Synthetic Fiber Production Facilities § 60.602 Standard for volatile organic compounds. On and after...

2010-07-01

342

40 CFR 60.602 - Standard for volatile organic compounds.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 false Standard for volatile organic compounds. 60.602 Section 60...Standards of Performance for Synthetic Fiber Production Facilities § 60.602 Standard for volatile organic compounds. On and after...

2011-07-01

343

40 CFR 60.742 - Standards for volatile organic compounds.  

Code of Federal Regulations, 2010 CFR

...6 2010-07-01 2010-07-01 false Standards for volatile organic compounds. 60.742 Section 60.742 Protection...Supporting Substrates Facilities § 60.742 Standards for volatile organic compounds. (a) Each owner or operator...

2010-07-01

344

40 CFR 60.432 - Standard for volatile organic compounds.  

Code of Federal Regulations, 2010 CFR

... 6 2010-07-01 2010-07-01 false Standard for volatile organic compounds. 60.432 Section 60.432 Protection...Publication Rotogravure Printing § 60.432 Standard for volatile organic compounds. During the period of the...

2010-07-01

345

Information Technology and the Volatility of Firm Performance  

E-print Network

This study investigates the impact of IT investments and several contextual variables on the volatility of future earnings. We find evidence that IT investments strongly increases the volatility of future earnings and that ...

Hunter, Starling

2004-03-12

346

Storage Systems for Non-volatile Memory Devices  

E-print Network

This dissertation presents novel approaches to the use of non-volatile memory devices in building storage systems. There are many types of non-volatile memory devices, and they usually have better performance than regular magnetic hard disks...

Wu, Xiaojian

2011-10-21

347

Integration of Non-volatile Memory into Storage Hierarchy  

E-print Network

In this dissertation, we present novel approaches for integrating non-volatile memory devices into storage hierarchy of a computer system. There are several types of non- volatile memory devices, such as flash memory, Phase Change Memory (PCM), Spin...

Qiu, Sheng

2013-12-04

348

Workshop on Evolution of Martian Volatiles. Part 2  

NASA Technical Reports Server (NTRS)

Different aspects of martian science are discussed. Topics covered include: early Mars volatile inventory, evolution through time, geological influences, present atmospheric properties, soils, exobiology, polar volatiles, and seasonal and diurnal cycles

Jakosky, B. (Editor); Treiman, A. (Editor)

1996-01-01

349

An Operational Semantics including volatile for  

E-print Network

consistency restored. - Execution overhead of locks; - Danger of deadlock. But if mutation is rare, we can use CompoundData base; public void mutate() { synchronized (this) { base = base.clone().mutate(); } } public volatile CompoundData base; public void mutate() { synchronized (this) { base = base.clone

Boyland, John Tang

350

Shaken and Stirred: Explaining Growth Volatility  

Microsoft Academic Search

Abstract: This paper attempts to set forth a framework for thinking about growth volatility which is general enough to incorporatethe important structural, institutional, and policy variations among countries which might account for differences in theirmacroeconomic performance. And it focuses particularly on the role of the financial sector. The paper is divided into 2sections. The first discusses the importance of short

William Easterly; Roumeen Islam; Joseph E. Stiglitz

2000-01-01

351

Volatile organic compounds of Schenella pityophilus.  

PubMed

Volatile organic compounds of Schenella pityophilus have been identified via solid-phase microextraction-gas chromatography-mass spectrometry analysis. Ten compounds have been identified, in which 3-methylthio-1-propene was the most significant component. Some other components were previously identified in Tuber aestivum and Tuber melanosporum. PMID:22236093

D'Auria, Maurizio; Racioppi, Rocco; Rana, Gian Luigi

2013-01-01

352

Analytical aspects of volatile substance abuse (VSA).  

PubMed

Through a case report, the authors illustrate the volatile substance abuse (VSA) toxicological investigation difficulties mainly due to evaporation of the compounds from postmortem samples and to the lack of reference data for interpretation. A 17-year-old man, student in a chemistry institute, was found dead with a plastic bag placed over his head. Several chemical substances were found in his belongings. Autopsy findings included serious pulmonary lesions and hemorrhagic digestive ulcerations. A large screening of drugs and toxic compounds and selective analyses for several classes of drugs of abuse were carried out in the autopsy samples. In particular, a headspace (HS), -gas chromatography/-mass spectrometry (GC/MS) technique was used to screen for volatile substances and metabolites in the biological samples and for residues of volatile substances on the surface of the plastic bag and in the chemicals found on the scene. The main analytical finding was the presence of alkanes (heptane, methyl-2-pentane, methyl-3-hexane, methylcyclohexane) in the gastric content. The literature data, VSA practices, long time-delay between death and autopsy, preservation conditions of the biological samples before analysis, and in-lab experiments on evaporation of volatile substances were considered to interpret this result. The present fatality was attributed to VSA with a gasoline-based stain remover like "eau écarlate," associated with a hypoxic recreation practice using a plastic bag. PMID:12877311

Gaulier, Jean-Michel; Tonnay, Véronique; Faict, Thierry; Sayer, Hervé; Marquet, Pierre; Lachâtre, Gérard

2003-07-01

353

Volatiles in interplanetary dust particles and aerogels  

NASA Technical Reports Server (NTRS)

Volatiles measured in 25 interplanetary dust particles (IDPs) are a mixture of both indigenous materials and contaminants associated with the collection and processing of the ODPs prior to analysis. Most IDPs have been collected in the stratosphere using a silicone oil/freon mixture (20:1 ratio) coated on collector plates. Studies have shown that silicone oil, freon and hexane residues remain with the ODPs, despite attempts to clean the IDPs. Analysis of the IDPs with the LMMS-technique produces spectra with a mixture of indigeneous and contaminants components. The contamination signal can be identified and removed; however, the contamination signal may obscure some of the indigeneous component's signal. Employing spectra stripping techniques, the indigenous volatile constituents associated with the IDPs can be identified. Volatiles are similar to those measured in CI or CM carbonaceous chondrites. Collection of IDPs in low-Earth orbit utilizing a Cosmic Dust Collection Facility attached to Space Station Freedom has been proposed. The low-density material aerogel has been proposed as a collection substrate for IDPs. Our studies have concentrated on identifying volatile contaminants that are associated with aerogel. We have found that solvents used for the preparation of aerogel remain in aerogel and methods must be developed for removing the entrapped solvents before aerogels can be used for an IDP collection substrate.

Gibson, E. K., Jr.; Harmetz, C. P.

1991-01-01

354

Floral Volatiles of Elaeagnus umbellata Thunb  

Microsoft Academic Search

The floral volatiles of Elaeagnus umbellata Thunb. (autumn olive) were isolated by simultaneous steam distillation\\/extraction and “purge and trap” techniques. Extracts were analyzed by GC\\/M S. In the steam distillate, 84 peaks were detected of which 56 were assigned structures. In the “purge and trap” analysis, 47 peaks were detected with 37 assigned structures. The principal steam distillate constituents were

Thomas L. Potter

1995-01-01

355

A nonlinear structural model for volatility clustering  

Microsoft Academic Search

A simple nonlinear structural model of endogenous belief heterogeneity is proposed. News about fundamentals is an IID random process, but nevertheless volatility clustering occurs as an endogenous phenomenon caused by the interaction between different types of traders, fundamentalists and technical analysts. The belief types are driven by adaptive, evolutionary dynamics according to the success of the prediction strategies as measured

A. Gaunersdorfer; C. H. Hommes

2005-01-01

356

A Nonlinear Structural Model for Volatility Clustering  

Microsoft Academic Search

A simple nonlinear structural model of endogenous belief heterogeneity is proposed. News about fundamentals is an IID random process, but nevertheless volatility clustering occurs as an endogenous phenomenon caused by the interaction between different types of traders, fundamentalists and technical analysts. The belief types are driven by an adaptive, evolutionary dynamics according to the success of the prediction strategies in

Andrea Gaunersdorfer; Cars H. Hommes

2000-01-01

357

Positive volatility simulation in the Heston model  

Microsoft Academic Search

In the Heston stochastic volatility model, the transition probability of the variance process can be represented by a non-central chi-square density. We focus on the case when the number of degrees of freedom is small and the zero boundary is attracting and attainable, typical in foreign exchange markets. We prove a new representation for this density based on sums of

Simon J. A. Malham; Anke Wiese

2008-01-01

358

Volatile components in okra seed coat  

Microsoft Academic Search

The volatile compounds in the coat of okra seeds can be released by simple rubbing of the seeds. They were isolated by hexane extraction and steam distillation to give the essential oil (EO) and by head space (HS) condensation. 72 compounds were identified in the study (40 esters and 24 sesquiterpenes and derivatives).The most abundant compound was 2-methylbutyl 2-methylbutanoate which

Marius Camciuc; Jean Marie Bessière; Gérard Vilarem; Antoine Gaset

1998-01-01

359

Emerging Control Technologies for Volatile Organic Compounds  

Microsoft Academic Search

Environmental problems associated with volatile organic compounds (VOCs) in the atmosphere have provided the driving force for sustained fundamental and applied research in the area of environmental remediation. Conventional methods currently used to treat VOCs include incineration, condensation, adsorption, and absorption. Incineration and condensation are cost-effective only for moderate to high VOC concentrations. Adsorption and absorption do not destroy VOCs

Geeta Rani Parmar; N. N. Rao

2008-01-01

360

Exposure to Volatile Methacrylates in Dental Personnel  

Microsoft Academic Search

Dental personnel are exposed to acrylates due to the acrylic resin-based composites and bonding agents used in fillings. It is well known that these compounds can cause contact allergy in dental personnel. However, in the 1990s, reports emerged on asthma also caused by methacrylates. The main volatile acrylates in dentistry are 2-hydroxyethyl methacrylate and methyl methacrylate. The aim of this

Stig Hagberg; Göran Ljungkvist; Harriet Andreasson; Stig Karlsson; Lars Barregård

2005-01-01

361

ALIPHATIC HALOGENATED HYDROCARBONS PRODUCE VOLATILE 'SALMONELLA' MUTAGENS  

EPA Science Inventory

Production of volatile mutagenic metabolites from 5 halogenated promutagens was examined by a simple modification of the conventional Salmonella/microsome mutagenicity assay. This method incorporates the taping together of 2 agar plates face to face during the initial portion of ...

362

Financial Market Integration and Macroeconomic Volatility  

Microsoft Academic Search

The process of financial market integration is modeled in an intertemporal general equilibrium framework as the elimination of trading frictions between financial markets in different countries. Goods markets are assumed to be imperfectly competitive and goods prices are subject to sluggish adjustment. Simulation experiments show that increasing financial market integration increases the volatility of a number of variables when shocks

Alan Sutherland

1996-01-01

363

Volatile Sulphur Compounds in UHT Milk  

Microsoft Academic Search

Several volatile sulphur compounds have been detected in raw and processed milk. These are hydrogen sulphide, methanethiol, carbonyl sulphide, dimethyl sulphide, carbon disulphide, dimethyl disulphide, dimethyl trisulphide, dimethyl sulphoxide, and dimethyl sulphone. Many of these increase in milk during heat processing and are associated with the cooked flavor of heat-treated milks, particularly UHT and sterilized milk. Several researchers have attempted

Z. Al-Attabi; B. R. DArcy; H. C. Deeth

2008-01-01

364

Volatile organic compounds of Schenella pityophilus  

Microsoft Academic Search

Volatile organic compounds of Schenella pityophilus have been identified via solid-phase microextraction-gas chromatography–mass spectrometry analysis. Ten compounds have been identified, in which 3-methylthio-1-propene was the most significant component. Some other components were previously identified in Tuber aestivum and Tuber melanosporum.

Maurizio D’Auria; Rocco Racioppi; Gian Luigi Rana

2012-01-01

365

Biological Activity of Volatile Fungal Metabolites  

Microsoft Academic Search

A RECENT survey has measured the effects of volatile metabolites from sixty-two fungal cultures on chosen characters of growth and reproduction of five assay species, namely: Rhizopus sexualis (Smith) Callen, Chaetomium globosum Kunze ex Fr., Stereum hirsutum (Willd.) Fr., Aspergillus niger van Tiegh., and Botrytis cinerea Pers. ex Fr. The sixty-two species tested consisted of thirteen Phycomycetes, thirteen Ascomycetes, six

Christine M. Dick; S. A. Hutchinson

1966-01-01

366

COMPLETE CATALYTIC OXIDATION OF VOLATILE ORGANICS  

EPA Science Inventory

The paper reviews heterogeneous catalytic oxidation, focusing on its application to the control of volatile organic compounds (VOCs) at operating conditions typical of field applications. The parameters for this review are: low to moderate temperatures (25-400 C), atmospheric pre...

367

Volatility of the diglycolamine salt of dicamba  

E-print Network

Laboratory, the Texas A&M University campus and the Texas A&M Riverside campus near College Station, TX. Rate-response and herbicide volatility data were collected using cotton (Gossypium hirsutum L.) and soybean (Glycine max (L.) Merr.) as test...

Sciumbato, Audy Shane

2012-06-07

368

Bayesian Selection of Multivariate Stochastic Volatility Models  

Microsoft Academic Search

We propose a Bayesian approach for selecting restrictions on multivariate regression models where the errors exhibit deterministic or stochastic volatilities. The model space is large and ex- haustive comparison of all possible restrictions is infeasible. We develop a Bayesian stochastic search method through Markov Chain Monte Carlo (MCMC) algorithms that generate posterior restrictions on the regression coe-cients and Cholesky decompositions

Antonello Loddo; Dongchu Sun

2006-01-01

369

The nitrogen source impacts major volatile compounds released by Saccharomyces cerevisiae during alcoholic fermentation.  

PubMed

Sulphur-containing amino acids, cysteine and methionine, are generally found in very low concentrations in grape-juice. The objective of this study was to identify the effects of methionine on aroma compounds formation. Nitrogen source effects on growth, fermentative behaviour and aroma compounds formation were evaluated in three strains of Saccharomyces cerevisiae cultivated in batch under moderate nitrogen concentration, 267mg YAN/L, supplied as di-ammonium phosphate (DAP), a mixture of amino acids with (AA) or without methionine (AA(wMet)), and a mixture of AA plus DAP. Fermentative vigour and final biomass yields were dependent on the nitrogen source, for each of the strains tested, in particular for EC1118. Additionally, despite the strain-dependent behaviour with respect to the basal level of H(2)S produced, the comparison of treatments AA and AA(wMet) showed that presence of methionine suppressed H(2)S production in all strains tested, and altered aroma compound formation, particularly some of those associated with fruity and floral characters which were consistently more produced in AA(wMet). Moreover, DAP supplementation resulted in a remarkable increase in H(2)S formation, but no correlation between sulphide produced and yeast fermentative vigour was observed. Results suggest that the use of different nitrogen sources results in the production of wines with divergent aroma profiles, most notably when EC1118 strain is used. Methionine determination and its management prior to fermentation are crucial for suppressing H(2)S and to endowing beverages with diverse sensory traits. PMID:23177046

Barbosa, Catarina; Mendes-Faia, Arlete; Mendes-Ferreira, Ana

2012-11-15

370

The Influence of Topography on Volatile Transport  

NASA Astrophysics Data System (ADS)

Topography can exert important influences on volatile transport on bodies, such as Pluto and Triton, with global atmospheres supported by vapor pressure equilibrium with volatile frost on the surface. First, because local energy balance depends on the illumination angle, volatile frost will preferentially sublime from (condense on) areas tilted towards (away from) the Sun, as has been previously modelled at small spatial scales [e.g. 1]. Topographic features can also cause a completely different kind of vertical volatile transport resulting from the decrease in atmospheric pressure with altitude. On Pluto and Triton the sublimation flux from a topographic feature approximately one km high is comparable to the seasonal or inter-hemispheric sublimation flux (1 g/cm2^/year). To the extent that seasonal transport influences the distribution of volatile ices (and related characteristics such as albedo, emissivity, reflectance spectrum), topography-driven transport will exert a comparable influence around features a km or more above (or below) the global mean altitude of the frost deposits. This implies that in addition to there being a global "frost temperature" (defined by the temperature at which the frost vapor pressure equals the atmospheric pressure), there is a "frost altitude" (defined by the globally-averaged altitude of all the volatile frost). The sense of topography-driven volatile transport is to denude high areas. Consider two frost patches with equilibrium temperatures equal to the frost temperature, but at different altitudes. The high(low)-altitude patch is in contact with a lower(higher)-pressure atmosphere due to the e^(-z/H) dependence of atmospheric pressure. If the high(low)-altitude patch is above(below) the frost altitude, frost will sublime from (condense on) the high (low) frost patch, resulting in net downhill transport. We present models for the combined effects of illumination and altitude on frost transport rates for simple topographic features and discuss how these may influence the appearance of Pluto's surface as it will be seen by the New Horizons spacecraft in July 2015. [1] Yelle (1992) Science 255, 1553-1555.

Stansberry, John A.; Grundy, Will; Young, Leslie

2014-11-01

371

Forecasting Volatility in Stock Market Using GARCH Models  

E-print Network

for dealing with heteroscedastic time series. Keywords: Volatility Heteroscedastic time series GARCH (P,Q) model GJR-GARCH(P,Q) model EGARCH(P,Q) model v contents 1 Introduction 1.1 Volatility ?????????????????????????..1 1.2 Why... Forecasting Volatility is so important????????????..3 1.3 Heteroscedastic time series??????????????????...5 1.4 Some popular Volatility Models????????????????...6 1.4.1 Exponentially Weighted Moving Average (EWMA)???..???..6 1.4.2...

Yang, Xiaorong

2008-01-01

372

Does implied volatility of currency futures option imply volatility of exchange rates?  

NASA Astrophysics Data System (ADS)

By investigating currency futures options, this paper provides an alternative economic implication for the result reported by Stein [Overreactions in the options market, Journal of Finance 44 (1989) 1011-1023] that long-maturity options tend to overreact to changes in the implied volatility of short-maturity options. When a GARCH process is assumed for exchange rates, a continuous-time relationship is developed. We provide evidence that implied volatilities may not be the simple average of future expected volatilities. By comparing the term-structure relationship of implied volatilities with the process of the underlying exchange rates, we find that long-maturity options are more consistent with the exchange rates process. In sum, short-maturity options overreact to the dynamics of underlying assets rather than long-maturity options overreacting to short-maturity options.

Wang, Alan T.

2007-02-01

373

Proboscis extension reflex platform for volatiles and semi-volatiles detection  

DOEpatents

The present invention provides an apparatus for the detection of volatile and semi-volatile chemicals using the olfactory abilities of honey bees that are trained to respond to the presence of a specific chemical in a sample of gas with the proboscis extension reflex (PER). In particular, the geometry and arrangement of the parts of the apparatus are such that the amount of surface area in contact with the sample of gas prior to its introduction to the bees is minimized to improve the detection of particular volatile and semi-volatile that have a tendency to "stick" to contacting surfaces, especially certain chemicals associated with explosives and narcotics. According to another aspect of the present invention, a pre-concentrating means is incorporated with the device to effectively increase the concentration of "sticky" chemicals presented to the insects.

Wingo, Robert M. (Los Alamos, NM); McCabe, Kirsten J. (Los Alamos, NM); Haarmann, Timothy K. (Jemez Pueblo, NM)

2010-11-30

374

Globalization and Uncertainty: Earnings Volatility in Sweden, 1985–2003  

Microsoft Academic Search

Earnings volatility has been linked to economic integration only through contradictory conjectures. We assess globalization’s role by examining volatility trends in manufacturing, private services, and public services. If trade increases uncertainty, volatility trends should differ markedly across industries since manufacturing, in contrast to especially public services, is exposed to international competition. We analyze earnings trajectories in Sweden 1985–2003, a country

MARTIN HÄLLSTEN; TOMAS KORPI; MICHAEL TÅHLIN

2010-01-01

375

Globalization and Uncertainty: Earnings Volatility in Sweden, 1985-2003  

Microsoft Academic Search

Earnings volatility has been linked it to economic integration only through contradictory conjectures. We assess globalization’s role by examining volatility trends in manufacturing, private services, and public services. If trade increases uncertainty, volatility trends should differ markedly across industries since manufacturing, in contrast to especially public services, is exposed to international competition. We analyze earnings trajectories in Sweden 1985-2003, a

Martin Hällsten; Tomas Korpi; Michael Tåhlin

2009-01-01

376

Another Look at the Volatility of Stock Prices  

ERIC Educational Resources Information Center

Investors are interested in the volatility of a stock for various reasons. One investor may desire to purchase a low volatility stock for peace of mind. Another may be interested in a high volatility stock in order to have the opportunity to buy low and sell high as the price of the stock oscillates. This author had the fortunate timing of reading…

Maruszewski, Richard F., Jr.

2007-01-01

377

The impact of market volatility on the cell therapy industry.  

PubMed

Stock market volatility in the cell therapy industry has greatly hindered the investment necessary to fund translational therapies. Here, we review the volatility of leading companies and suggest that a distinct industry is maturing to a point at which the volatility should subside, providing a more attractive environment for future growth. PMID:22056137

Brindley, David A; Reeve, Brock C; Sahlman, William A; Bonfiglio, Greg A; Davie, Natasha L; Culme-Seymour, Emily J; Mason, Chris

2011-11-01

378

Ruminant fat volatiles as affected by diet. A review  

Microsoft Academic Search

Volatile compounds in meat have been widely studied for their favourable or undesirable effects on meat flavour, or for their potential use in tracing the animal feeding system. To date, the chemical mechanisms causing the appearance of volatile compounds in meat have been largely understood. Several variables are involved in the accumulation of volatiles in animal tissues and among them

V. Vasta; A. Priolo

2006-01-01

379

Stock returns and volatility in emerging financial markets  

Microsoft Academic Search

This paper studies the dynamics of expected stock returns and volatility in emerging financial markets. We find clustering, predictability and persistence in conditional volatility, as others have documented for mature markets. However, emerging markets exhibit higher conditional volatility and conditional probability of large price changes than mature markets. Exposure to high country-specific risk does not appear to be rewarded with

Selahattin imrohoroglu

1997-01-01

380

Exchange rate volatility and exports in South Africa 1  

Microsoft Academic Search

This paper examines the characteristics of short-term fluctuations\\/volatility of the South African exchange rate and investigates whether this volatility has affected the South Africa's exports flows. In particular the paper investigates the impact of exchange rate volatility on aggregate South African exports flows to the rest of the world, as well as on South African goods, services and gold exports.

K. R. Todani; T. V. Munyama

2005-01-01

381

Characteristics of Volatile Compounds of Starches Extracted with Aqueous Solutions  

Microsoft Academic Search

Volatile compounds of wheat, corn, and potato starches were determined prior to and upon extraction of the starches with aqueous solutions of sodium hydroxide (NaOH), ethanol, and sodium dodecyl sulfate (SDS). Aqueous NaOH extraction was effective in reducing the level of total volatiles and removing certain volatiles from both wheat and corn starches without increasing the level of hexanal, an

Abdulvahit Sayaslan

2006-01-01

382

System of extraction of volatiles from soil using microwave processes  

NASA Technical Reports Server (NTRS)

A device for the extraction and collection of volatiles from soil or planetary regolith. The device utilizes core drilled holes to gain access to underlying volatiles below the surface. Microwave energy beamed into the holes penetrates through the soil or regolith to heat it, and thereby produces vapor by sublimation. The device confines and transports volatiles to a cold trap for collection.

Ethridge, Edwin C. (Inventor); Kaukler, William F. (Inventor)

2013-01-01

383

Evolution of plant volatile production in insect-plant relationships  

Microsoft Academic Search

Summary The production of volatile secondary plant substances during the evolution of terrestrial plants is reviewed in regard to the defensive systems of plants to microorganisms and herbivores. Plant volatiles can be produced by both anabolic and catabolic processes. Although attraction of pollinators is a well-studied phenomenon, functions of volatiles range from excretion of waste products to the production of

Paul Harrewijn; Albert K. Minks; Chris Mollema

1994-01-01

384

Online measurements of the emissions of intermediate-volatility and semi-volatile organic compounds from aircraft  

E-print Network

A detailed understanding of the climate and air quality impacts of aviation requires measurements of the emissions of intermediate-volatility and semi-volatile organic compounds (I/SVOCs) from aircraft. Currently both the ...

Herndon, S. C.

385

Volatile Evolution of Magma Associated with the Solchiaro Eruption in the Phlegrean Volcanic District (Italy)  

NASA Astrophysics Data System (ADS)

The Phlegrean volcanic district (PVD) in southern Italy is one of the best known volcanic hazard areas in the world. More than 1.5 million people live in close proximity to the volcanic centers. The PVD comprises three volcanic fields: the Campi Flegrei caldera and the islands of Ischia and Procida. We studied volatiles plus major and trace elements in the magma associated with the Solchiaro eruption on the Island of Procida, Italy, to gain a better understanding of the relationship between pre-eruptive volatiles and magmatic evolution. The Solchiaro eruption is one of the more primitive products erupted in the PVD and provides information on the source of later more evolved magmas associated with this volcanic system. The composition of the magma before eruption was determined by analyzing 104 melt inclusions (MIs) in forsteritic olivine, glass embayment plus rim glasses, and high vesciculated glasses selected from 4 representative samples. The composition of MIs was recalculated and ranges from basaltic to trachy-basaltic. Among major elements potassium shows the highest variability, from 0.5 to 6 wt%. MI define a continuous trend based on major and minor element compositions. Embayments matrix glass and high vesciculated glasses define a field that suggests a discontinuous process. Compatible to incompatible trace element ratios in early melts are highly variable and represent the melt phase before or at the very beginning of assimilation-fractional crystallization (FCA) processes. Intermediate melt compositions reflect continuing FCA processes, late melt compositions suggest that the FCA process was aborted before eruption. Volatile contents of early melt are highly variable and reflect source heterogeneities, and the melts are interpreted to be undersaturated. Intermediate melts were volatile saturated and H2O-CO2 contents define a degassing path. Depths of trapping of MI range from 4.4 to 2.2 km, and are calculated based on Newman and Lowenstern (2002) and assuming a pressure gradient of 270 bar/Km. Pressures of crystallization of intermediate melts correlate with magma evolution associated with FCA processes. At the moment of the eruption, melt saturated in volatiles at 8 km continuously lost volatiles during its rapid ascent to the surface. Glass embayments and glass at the crystal/melt interface shows higher volatiles (especially CO2), compared to highly vesiculated matrix glass. Magma compositions relative to some MIs hosted in forsterite-rich olivine show extremely low contents of both K2O and Na2O and high CaO (0.5, 1.90 and 13.89 wt% respectively). Similar compositions have not been previously reported from the PVD but are characteristic of the Aeolian Arc.

Esposito, R.; Bodnar, R. J.; de Vivo, B.; Lima, A.; Fedele, L.; Shimizu, N.; Hunter, J.

2009-12-01

386

Realized Volatility and Absolute Return Volatility: A Comparison Indicating Market Risk  

PubMed Central

Measuring volatility in financial markets is a primary challenge in the theory and practice of risk management and is essential when developing investment strategies. Although the vast literature on the topic describes many different models, two nonparametric measurements have emerged and received wide use over the past decade: realized volatility and absolute return volatility. The former is strongly favored in the financial sector and the latter by econophysicists. We examine the memory and clustering features of these two methods and find that both enable strong predictions. We compare the two in detail and find that although realized volatility has a better short-term effect that allows predictions of near-future market behavior, absolute return volatility is easier to calculate and, as a risk indicator, has approximately the same sensitivity as realized volatility. Our detailed empirical analysis yields valuable guidelines for both researchers and market participants because it provides a significantly clearer comparison of the strengths and weaknesses of the two methods. PMID:25054439

Takaishi, Tetsuya; Stanley, H. Eugene; Li, Baowen

2014-01-01

387

Realized volatility and absolute return volatility: a comparison indicating market risk.  

PubMed

Measuring volatility in financial markets is a primary challenge in the theory and practice of risk management and is essential when developing investment strategies. Although the vast literature on the topic describes many different models, two nonparametric measurements have emerged and received wide use over the past decade: realized volatility and absolute return volatility. The former is strongly favored in the financial sector and the latter by econophysicists. We examine the memory and clustering features of these two methods and find that both enable strong predictions. We compare the two in detail and find that although realized volatility has a better short-term effect that allows predictions of near-future market behavior, absolute return volatility is easier to calculate and, as a risk indicator, has approximately the same sensitivity as realized volatility. Our detailed empirical analysis yields valuable guidelines for both researchers and market participants because it provides a significantly clearer comparison of the strengths and weaknesses of the two methods. PMID:25054439

Zheng, Zeyu; Qiao, Zhi; Takaishi, Tetsuya; Stanley, H Eugene; Li, Baowen

2014-01-01

388

for Undergraduate CHEMISTRY MAJORS  

E-print Network

Technology, Colloid and Surface Chemistry, Consumer Products, Food and Flavor Chemistry, Forensic ChemistryHANDBOOK for Undergraduate CHEMISTRY MAJORS DEPARTMENT OF CHEMISTRY Fall 2010 #12;#12;TABLE OF CONTENTS A Career in Chemistry - What It Means ___________________________________________ 4 What do

Stuart, Steven J.

389

CTEP — Major Initiatives  

Cancer.gov

Skip to Content Home | Investigator Resources | Protocol Development | Initiatives/Programs/Collaborations | Links to More Resources | Funding Opportunities | About CTEP Home | Sitemap | Contact CTEP Search this site Major Initiatives CTEP Home CTEP

390

Major Appliance Management Report.  

National Technical Information Service (NTIS)

Major appliances (also called 'white goods') have long been managed as part of the traditional municipal solid waste (MSW) stream, with the most common management method being landfill disposal. Over the past several years, it has become increasingly appa...

M. Robertson, K. F. O'Donnell

1990-01-01

391

Majors Available Connecticut  

E-print Network

Majors Available Connecticut Bioengineering Electrical Engineering Technology Forest Operations Management Technology Forest Operations, Bioproducts and Bioenergy Forestry Marine Science Mechanical Engineering Technology Parks, Recreation and Tourism Pulp and Paper Technology* Surveying Engineering

Thomas, Andrew

392

Majors Available Connecticut  

E-print Network

Majors Available Connecticut Biological Engineering Electrical Engineering Technology Forest Management Technology Forest Operations Science Forestry Marine Science Mechanical Engineering Technology Parks, Recreation and Tourism Pulp and Paper Technology* Surveying Engineering Technology Sustainable

Thomas, Andrew

393

Choosing a Major  

NSDL National Science Digital Library

By completing this tutorial, you should be able to: Find resources to help you find the correct business major for you. Access your business major options. Congratulations on choosing Utah State University and the Jon M. Huntsman School of Business as your educational partner. Now that you have been admitted to USU, you may have a few questions about where to go from here. Below you will find many resources that will help you ...

Heiniger, Joslyn

2009-09-27

394

The Accounting Major  

NSDL National Science Digital Library

By completing this tutorial, you should be able to: Find resources to aid in your research of the Accounting Major. Identify key aspects of an accounting career. Congratulations on choosing Utah State University and the Jon M. Huntsman School of Business as your educational partner. Now that you have been admitted to USU and selected accounting as your Huntsman major, you may have a few questions about where to go from here. Below you will ...

Heiniger, Joslyn

2009-12-04

395

Synergy Between Astrochemical Models and Cometary Taxonomies of Parent Volatiles  

NASA Astrophysics Data System (ADS)

The principal output in taxonomic studies of cometary primary (parent) volatiles is the suite of “mixing ratios” between observed species. These ratios relate the abundances of different molecules (CH4/C2H2/C2H6/H2CO/CH3OH/H2O, etc.) or isotopologues (HDO/H2O, CH3D/CH4, etc.). Infrared and radio observations have found strong evidence that mixing ratios vary substantially among comets. However, we still face serious uncertainties in decoding the cosmogonic significance of the measured abundances. The observed composition of comets may be an end product of a variety of processes, including chemical evolution in the protoplanetary disk, dynamical evolution in the young solar system, and (perhaps) thermal evolution during successive perihelion passages. Improved understanding of their relative importance requires additional sensitive measurements and a comprehensive synergy with astrochemical models. These models find that protoplanetary disks can be divided into three distinct regions: (1) a cold midplane, where ices freeze to dust grains; (2) a warm molecular layer, where ices sublimate and are processed via gas-phase reactions; and (3) a hot disk atmosphere containing predominantly atoms and atomic ions. Material from the different layers can be mixed by transport processes.We will show how this synergy is being realized via close collaboration between modeling and observing teams. The goal is a deeper insight into the processes preceding comet formation that may have influenced the composition - what chemical reaction pathways dominated the synthesis of cometary compounds? What processes in the protoplanetary disk have left strong signatures in cometary ices? Can models provide testable predictions for the chemical diversity observed among comets? Addressing these questions, we will show initial comparisons between relative abundances for several cometary volatiles and those predicted for the midplane of the protoplanetary disk where comets formed. We will also discuss how models link observations of volatiles in comets with studies of protoplanetary disks around solar type stars.This work is supported by NSF (AAG) and NASA (Astrobiology, PATM, PAST). Astrophysics at QUB is supported by a grant from STFC.

Bonev, Boncho P.; Willacy, Karen; Mumma, Michael J.; Gibb, Erika L.; Millar, Tom; Charnley, Steve; DiSanti, Michael A.; Villanueva, Geronimo L.; Paganini, Lucas

2014-11-01

396

Quantitative variation and biosynthesis of hindgut volatiles associated with the red turpentine beetle, Dendroctonus valens LeConte, at different attack phases.  

PubMed

The red turpentine beetle (RTB), Dendroctonus valens LeConte, is a destructive invasive forest pest in China. For such tree-killing species, how to initiate a volatile-mediated mass attack is of great importance during the course of establishment. To understand the hindgut volatile production mechanism underlying mass attack initiated by RTB, coupled gas chromatography-mass spectrometry and 13C-labelled precursors were applied to explore the quantitative variation and biosynthesis of volatiles associated with RTB at different attack phases. Five previously described volatiles, trans-verbenol, myrtenol, cis-verbenol, myrtenal and verbenone, were identified and quantified from extracts of female and male hindguts, with the first two compounds as the major components and the latter three as minor constituents. In newly emerged females and males, only minute amounts of these compounds were detected. The quantity of volatiles from female adults significantly increased after they fed on bolts. Male adults also yielded larger quantities of volatiles after they joined females in galleries, which suggested that RTB males could accelerate the mass colonization on host trees. We also confirmed that RTB produced the five volatiles through oxidizing the major host monoterpene, alpha-pinene, but not synthesized de novo since products were labeled without 13C. The implication of this study in understanding the successful invasion of RTB is discussed. PMID:19671207

Shi, Z-H; Sun, J-H

2010-06-01

397

Volatile components in scent gland secretions of garter snakes ( Thamnophis spp.)  

Microsoft Academic Search

Previous analyses of the scent gland secretions of snakes have focused on the nonvolatile components. Gas chromatography-mass spectrometry of secretions from North American garter snakes (Thamnophis butleri, T. couchi, T. elegans, T. melanogaster, andT. sirtalis) indicated the following seven major volatile components: acetic, propanoic, 2-methylpropanoic, butanoic, and 3-methylbutanoic acids, trimethylamine, and 2-piperidone. Five or more of these compounds were observed

William F. Wood; Joshua M. Parker; Paul J. Weldon

1995-01-01

398

Volatile Compounds From Fruits of Talisia esculenta (A. St.-Hil.) Radlk. (Sapindaceae)  

Microsoft Academic Search

The volatile compounds from fruits of Talisia esculenta harvested in northeastern Brazil, were obtained by hydrodistillation using Clevenger-type apparatus and analyzed by GC-FID and GC\\/MS. Nineteen compounds were identified and pyrazines were the major compounds (representing 64.8–70.4% of the oil), mainly 2,5-diethylpyrazine (64.2–69.1%). Oxygenated monoterpenes also predominated (6.6–6.8% of the oil) besides high abundance of furfural (18.0–22.8%).

Tatiana Kubota; Paulo C. L. Nogueira; Péricles B. Alves; Samísia M. F. Machado; Valéria R. S. Moraes

2009-01-01

399

Volatile organic components migrating from plastic pipes (HDPE, PEX and PVC) into drinking water  

Microsoft Academic Search

High-density polyethylene pipes (HDPE), crossbonded polyethylene pipes (PEX) and polyvinyl chloride (PVC) pipes for drinking water were tested with respect to migration of volatile organic components (VOC) to water. The odour of water in contact with plastic pipes was assessed according to the quantitative threshold odour number (TON) concept. A major migrating component from HDPE pipes was 2,4-di-tert-butyl-phenol (2,4-DTBP) which

Ingun Skjevrak; Anne Due; Karl Olav Gjerstad; Hallgeir Herikstad

2003-01-01

400

Volatilization of tin as stannane in anoxic environments  

NASA Astrophysics Data System (ADS)

Recent reports of volatilization of metals from the aquatic environment demonstrate a previously unsuspected loss from the aquatic metal budget. Volatilization can occur by various mechanisms. Arsenic volatilizes from the aquatic environment as trimethyl- and dimethylarsine formed by biomethylation1; plants and soils form volatile selenium compounds2; volatilization of mercury from the oceans might rival that of anthropogenic origin3; maritime air can contain a significantly higher fraction of alkyl-lead compounds to total lead than continental or urban air4. Finally, increasing evidence suggests the potential importance of tin volatilization through formation of tetramethyltin by chemical or biological methylation in the environment5 7. We recently described possible formation of tetramethyltin by the macroalgae Enteromorpha sp. under oxic conditions6. Here we examine the contribution of decaying algal material to environmental cycling of tin by describing formation of volatile stannane (SnH4) in anoxic environments.

Donard, Olivier F. X.; Weber, James H.

1988-03-01

401

Major international sport profiles.  

PubMed

Sports are part of the sociocultural fabric of all countries. Although different sports have their origins in different countries, many sports are now played worldwide. International sporting events bring athletes of many cultures together and provide the opportunity not only for athletic competition but also for sociocultural exchange and understanding among people. This article reviews five major sports with international appeal and participation: cricket, martial arts, field hockey, soccer, and tennis. For each sport, the major aspects of physiological and biomechanical demands, injuries, and prevention strategies are reviewed. PMID:12296532

Patel, Dilip R; Stier, Bernhard; Luckstead, Eugene F

2002-08-01

402

Enhanced Sensitivity for High Spatial Resolution Lipid Analysis by Negative Ion Mode MALDI Imaging Mass Spectrometry  

PubMed Central

We have achieved enhanced lipid imaging to a ~10 ?m spatial resolution using negative ion mode matrix assisted laser desorption ionization (MALDI) imaging mass spectrometry, sublimation of 2,5-dihydroxybenzoic acid as the MALDI matrix and a sample preparation protocol that uses aqueous washes. We report on the effect of treating tissue sections by washing with volatile buffers at different pHs prior to negative ion mode lipid imaging. The results show that washing with ammonium formate, pH 6.4, or ammonium acetate, pH 6.7, significantly increases signal intensity and number of analytes recorded from adult mouse brain tissue sections. Major lipid species measured were glycerophosphoinositols, glycerophosphates, glycerolphosphoglycerols, glycerophosphoethanolamines, glycerophospho-serines, sulfatides, and gangliosides. Ion images from adult mouse brain sections that compare washed and unwashed sections are presented and show up to fivefold increases in ion intensity for washed tissue. The sample preparation protocol has been found to be applicable across numerous organ types and significantly expands the number of lipid species detectable by imaging mass spectrometry at high spatial resolution. PMID:22243218

Angel, Peggi M.; Spraggins, Jeffrey M.; Baldwin, H. Scott; Caprioli, Richard

2012-01-01

403

Volatile organic compounds in ambient aerosols  

NASA Astrophysics Data System (ADS)

In order to investigate the concentration levels of volatile organic compounds (VOCs) in ambient aerosols, monocyclic aromatic hydrocarbons (MAHs) and chlorinated hydrocarbons (CHs) in the particulate phase were measured simultaneously with those in the gas phase in the urban atmosphere. Six compounds were detected in the aerosols at concentrations from 0.051 (1,2-dichloroethane) to 1.75 ng m - 3 (benzene). Benzene was detected as the most dominant compound in the aerosols, although toluene was the most dominant compound in the gas phase. The VOCs in the aerosols had concentrations comparable to those reported for some semi-volatile organic compounds (SOCs) in the aerosols. The concentrations of the VOCs in the aerosols were primarily controlled by the aerosol mass loading. Temperature and relative humidity had no significant effect on the gas/particle partitioning of the VOCs. Our results also suggested that the hygroscopic properties of the aerosols should be considered to discuss the partitioning of the VOCs.

Matsumoto, Kiyoshi; Matsumoto, Kumi; Mizuno, Riichi; Igawa, Manabu

2010-07-01

404

Volatile fingerprints of cancer specific genetic mutations  

PubMed Central

We report on a new concept for profiling genetic mutations of (lung) cancer cells, based on the detection of patterns of volatile organic compounds (VOCs) emitted from cell membranes, using an array of nanomaterial-based sensors. In this in-vitro pilot study we have derived a volatile fingerprint assay for representative genetic mutations in cancer cells that are known to be associated with targeted cancer therapy. Five VOCs were associated with the studied oncogenes, using complementary chemical analysis, and were discussed in terms of possible metabolic pathways. The reported approach could lead to the development of novel methods for guiding treatments, so that patients could benefit from safer, more timely and effective interventions that improve survival and quality of life while avoiding unnecessary invasive procedures. Studying clinical samples (tissue/blood/breath) will be required as next step in order to determine whether this cell-line study can be translated into a clinically useful tool. PMID:23428987

Peled, Nir; Barash, Orna; Tisch, Ulrike; Ionescu, Radu; Broza, Yoav Y.; Ilouze, Maya; Mattei, Jane; Bunn, Paul A.; Hirsch, Fred R.; Haick, Hossam

2014-01-01

405

Volatiles from rhizomes of Rhodiola rosea L.  

PubMed

Terpenes and aroma volatiles from rhizomes of Rhodiola rosea L. from Norway have been isolated by both steam distillation and headspace solid-phase micro-extraction coupled with gas chromatography and mass spectrometry analysis. The dried rhizomes contained 0.05% essential oil with the main chemical classes: monoterpene hydrocarbons (25.40%), monoterpene alcohols (23.61%) and straight chain aliphatic alcohols (37.54%). n-Decanol (30.38%), geraniol (12.49%) and 1,4-p-menthadien-7-ol (5.10%) were the most abundant volatiles detected in the essential oil, and a total of 86 compounds were identified in both the SD and HS-SPME samples. Geraniol was identified as the most important rose-like odour compound besides geranyl formate, geranyl acetate, benzyl alcohol and phenylethyl alcohol. Floral notes such as linalool and its oxides, nonanal, decanal, nerol and cinnamyl alcohol highlight the flowery scent of rose root rhizomes. PMID:11867098

Rohloff, Jens

2002-03-01

406

Noise-induced volatility of collective dynamics  

NASA Astrophysics Data System (ADS)

Noise-induced volatility refers to a phenomenon of increased level of fluctuations in the collective dynamics of bistable units in the presence of a rapidly varying external signal, and intermediate noise levels. The archetypical signature of this phenomenon is that—beyond the increase in the level of fluctuations—the response of the system becomes uncorrelated with the external driving force, making it different from stochastic resonance. Numerical simulations and an analytical theory of a stochastic dynamical version of the Ising model on regular and random networks demonstrate the ubiquity and robustness of this phenomenon, which is argued to be a possible cause of excess volatility in financial markets, of enhanced effective temperatures in a variety of out-of-equilibrium systems, and of strong selective responses of immune systems of complex biological organisms. Extensive numerical simulations are compared with a mean-field theory for different network topologies.

Harras, Georges; Tessone, Claudio J.; Sornette, Didier

2012-01-01

407

Effects of ethanol and long-chain ethyl ester concentrations on volatile partitioning in a whisky model system.  

PubMed

Ethanolic atmospheric pressure chemical ionization mass spectrometry (APCI-MS) was used to analyze the headspace concentrations of a test set of 14 whisky volatile compounds above a series of aqueous ethanolic solutions differing in alcohol content (5-40% ABV) and with regard to concentration of ethyl hexadecanoate (0-500 mg/L). The latter was selected to represent the long-chain ethyl esters found at various concentrations in new-make spirit. Headspace ion intensities were modeled against ethanol and ethyl hexadecanoate concentrations as factors. A separate model was prepared for each compound. Not surprisingly, ethanol content in the range of 5-40% ABV had a significant effect (P < 0.0001) on headspace volatile concentrations of all volatile compounds, whereas the ethyl hexadecanoate concentration had a selective effect of reducing headspace concentrations of the more hydrophobic compounds (log P > 2.5). This finding is discussed in terms of the "structuring" effects of ethyl hexadecanoate when present above critical micelle concentration, leading to the selective incorporation of hydrophobic volatile compounds into the interior of micelle-like structures. Data presented illustrate that dilution of whiskies to 23% ABV for "nosing" in the presence of long-chain ethyl esters is likely to change the balance of volatile compounds in the headspace and thus the perceived aroma character. PMID:22958228

Boothroyd, Emily L; Linforth, Robert S T; Cook, David J

2012-10-10

408

Liquid chromatography separation of non-volatile components of fossil fuels at very high resolution. Final report  

Microsoft Academic Search

Characterization of the non-volatile fractions of various fossil fuels is of technological and environmental importance. The aim of our work is to develop very high efficiency preparative and analytical separations which allow more detailed chemical identification of selected compounds of interest. Using crude synfuel materials as model mixtures, we have evaluated two major sample fractionation approaches and preparative high-pressure liquid

Novotny

1984-01-01

409

Natural emissions of non-methane volatile organic compounds, carbon monoxide, and oxides of nitrogen from North America  

Microsoft Academic Search

The magnitudes, distributions, controlling processes and uncertainties associated with North American natural emissions of oxidant precursors are reviewed. Natural emissions are responsible for a major portion of the compounds, including non-methane volatile organic compounds (NMVOC), carbon monoxide (CO) and nitric oxide (NO), that determine tropospheric oxidant concentrations. Natural sources include soil microbes, vegetation, biomass burning, and lightning. These sources are

Alex Guenther; Chris Geron; Tom Pierce; Brian Lamb; Peter Harley; Ray Fall

2000-01-01

410

The distribution of rare earth elements between monzogranitic melt and the aqueous volatile phase in experimental investigations at 800 °C and 200 MPa  

Microsoft Academic Search

The partitioning of the rare earth elements between a peraluminous monzogranitic melt and a chloride-bearing, sulfur- and\\u000a carbon dioxide-free, aqueous volatile phase was examined experimentally as a function of chloride and major element concentrations\\u000a at 800?°C and 200?MPa. The light rare earth elements (e.g. La, Ce) partition into the aqueous volatile phase to a greater\\u000a extent than the heavy rare

Marshall J. Reed; Philip A. Candela; Philip M. Piccoli

2000-01-01

411

The sublethal effects of the non volatile water soluble fraction of Southern Louisiana crude oil on the growth of Skeletonema costatum (Greve.) Cleve  

E-print Network

THE SUBLETHAL EFFECTS OF THE NON VOLATILE WATER SOLUBLE FRACTION OF SOUTHERN LOUISIANA CRUDE OIL ON THE GROWTH OF Skeletonema costatum (GREVE. ) CLEVE A Thesis by SUE MYHRE SCHAUFFLER Submitted to the Graduate College of Texas ~I University... in partial fulfillment of the requirement for the degree of MASTER OF SCIENCE December 1979 Major Subject: Oceanography THE SUBLETHAL EFFECTS OF THE NON VOLATILE WATER SOLUBLE FRACTION OF SOUTHERN LOUISIANA CRUDE OIL ON THE GROWTH OF Skeletonema...

Schauffler, Sue Myhre

2012-06-07

412

Volatile components in forest stands of Karelia  

SciTech Connect

Study of the qualitative and quantitative composition of volatile organic compounds in forests stands of Karelia is made. A decrease in temperature and an increase in the relative air humidity adversely affect their emission. To study the relationship between the processes of the synthesis of essential oils in woody plants and the release of their components into the environment, a qualitative and quantitative determination of essential oils in pine branches was carried out. 13 refs., 3 figs., 4 tabs.

Fuksman, I.L. [Institute of Forestry, Karelia (Russian Federation)

1995-09-01

413

Volatile metabolites of pathogens: a systematic review.  

PubMed

Ideally, invading bacteria are detected as early as possible in critically ill patients: the strain of morbific pathogens is identified rapidly, and antimicrobial sensitivity is known well before the start of new antimicrobial therapy. Bacteria have a distinct metabolism, part of which results in the production of bacteria-specific volatile organic compounds (VOCs), which might be used for diagnostic purposes. Volatile metabolites can be investigated directly in exhaled air, allowing for noninvasive monitoring. The aim of this review is to provide an overview of VOCs produced by the six most abundant and pathogenic bacteria in sepsis, including Staphylococcus aureus, Streptococcus pneumoniae, Enterococcus faecalis, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Escherichia coli. Such VOCs could be used as biological markers in the diagnostic approach of critically ill patients. A systematic review of existing literature revealed 31 articles. All six bacteria of interest produce isopentanol, formaldehyde, methyl mercaptan, and trimethylamine. Since humans do not produce these VOCs, they could serve as biological markers for presence of these pathogens. The following volatile biomarkers were found for identification of specific strains: isovaleric acid and 2-methyl-butanal for Staphylococcus aureus; 1-undecene, 2,4-dimethyl-1-heptane, 2-butanone, 4-methyl-quinazoline, hydrogen cyanide, and methyl thiocyanide for Pseudomonas aeruginosa; and methanol, pentanol, ethyl acetate, and indole for Escherichia coli. Notably, several factors that may effect VOC production were not controlled for, including used culture media, bacterial growth phase, and genomic variation within bacterial strains. In conclusion, VOCs produced by bacteria may serve as biological markers for their presence. Goal-targeted studies should be performed to identify potential sets of volatile biological markers and evaluate the diagnostic accuracy of these markers in critically ill patients. PMID:23675295

Bos, Lieuwe D J; Sterk, Peter J; Schultz, Marcus J

2013-05-01

414

Volatile Metabolites of Pathogens: A Systematic Review  

PubMed Central

Ideally, invading bacteria are detected as early as possible in critically ill patients: the strain of morbific pathogens is identified rapidly, and antimicrobial sensitivity is known well before the start of new antimicrobial therapy. Bacteria have a distinct metabolism, part of which results in the production of bacteria-specific volatile organic compounds (VOCs), which might be used for diagnostic purposes. Volatile metabolites can be investigated directly in exhaled air, allowing for noninvasive monitoring. The aim of this review is to provide an overview of VOCs produced by the six most abundant and pathogenic bacteria in sepsis, including Staphylococcus aureus, Streptococcus pneumoniae, Enterococcus faecalis, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Escherichia coli. Such VOCs could be used as biological markers in the diagnostic approach of critically ill patients. A systematic review of existing literature revealed 31 articles. All six bacteria of interest produce isopentanol, formaldehyde, methyl mercaptan, and trimethylamine. Since humans do not produce these VOCs, they could serve as biological markers for presence of these pathogens. The following volatile biomarkers were found for identification of specific strains: isovaleric acid and 2-methyl-butanal for Staphylococcus aureus; 1-undecene, 2,4-dimethyl-1-heptane, 2-butanone, 4-methyl-quinazoline, hydrogen cyanide, and methyl thiocyanide for Pseudomonas aeruginosa; and methanol, pentanol, ethyl acetate, and indole for Escherichia coli. Notably, several factors that may effect VOC production were not controlled for, including used culture media, bacterial growth phase, and genomic variation within bacterial strains. In conclusion, VOCs produced by bacteria may serve as biological markers for their presence. Goal-targeted studies should be performed to identify potential sets of volatile biological markers and evaluate the diagnostic accuracy of these markers in critically ill patients. PMID:23675295

Bos, Lieuwe D. J.; Sterk, Peter J.; Schultz, Marcus J.

2013-01-01

415

Volatile organic compounds (VOCs) in soils  

Microsoft Academic Search

Soils may act as sources or sinks of volatile organic compounds (VOCs). Many of the formed VOCs are produced by microorganisms,\\u000a and it would be a challenge to investigate soil microbial communities by studying their VOC profile. Such “volatilomics” would\\u000a have the advantage of avoiding extraction steps that are often a limit in genomic or proteomic approaches. Abundant literature\\u000a on

Heribert Insam; Martin S. A. Seewald

2010-01-01

416

Volatilization of ethylene dibromide from water  

USGS Publications Warehouse

Overall mass-transfer coefficients for the volatilization of ethylene dibromide from water were measured simultaneously with the oxygen absorption coefficient in a laboratory stirred tank. Coefficients were measured as a function of mixing conditions in the water for two windspeeds. The ethylene dibromide mass-transfer coefficient depended on windspeed; the ethylene dibromide liquid-film coefficient did not, in agreement with theory. A constant relation existed between the liquid-film coefficients for ethylene dibromide and oxygen.

Rathbun, R.E.; Tai, D.Y.

1987-01-01

417

Photochemistry complicates attribution of volatile organics  

NASA Astrophysics Data System (ADS)

Understanding the sources of air pollution is important in mitigation efforts. Commonly used models known as receptor models often do not take into account chemical reactions that may occur between the source of the emission and the site where measurements are taken. To determine to what extent photochemical reactions in the atmosphere may be affecting source attribution of volatile organic compounds (VOCs), Yuan et al. measured VOCs at an urban site in Beijing in August-September 2010 and identified emission sources.

Balcerak, Ernie

2013-02-01

418

Post-irradiation changes of the volatile oil constituents of Monodora myristica (Gaertn) Dunal.  

PubMed

Volatile oil rich spices cannot be sterilised by pasteurisation because of the presence of thermal-sensitive components. In this article, we report the effect of irradiation on the volatile constituents of Monodora myristica. The samples were irradiated at ambient conditions at dose levels of 0 and 15?kGy using a linear accelerator at a dose rate of approximately 10(7)?Gy?s(-1). The volatile oil was extracted via headspace analysis and the quantification carried out with a HP-5MS fused silica column. Twenty-three constituents were identified with alpha-phellandrene as the major constituent (53%). Electron-beam irradiation of M. myristica did not significantly affect the volatile constituent profile at 15?kGy. Except alpha-thujene, which was increased from 7.18% to 16.76%, the most affected constituents were those that constitute less than 0.10% of the oil. Irradiation could be an effective way for decontamination of M. myristica. PMID:22054412

Onyenekwe, Paul Chidozie; Stahl, Mario; Adejo, Godwin

2012-11-01

419

Rust and schreibersite in Apollo 16 highland rocks - Manifestations of volatile-element mobility  

NASA Technical Reports Server (NTRS)

Rust is a manifestation of halogen and volatile-metal mobility in the lunar environment. Schreibersite is stable as the primary phosphorus-bearing phase in the highland rocks, a consequence of the inherently low oxygen fugacity within impact-generated melts. Apatite and whitlockite are subordinate in these rocks. The partitioning of P into phosphide in impact-generated melts, and the failure of phosphate to crystallize, effects a decoupling of the halogens and phosphorus. Of the Apollo 16 rocks, 63% contain rust, 70% contain schreibersite, and 52% contain both phases, thereby establishing the pervasiveness of volatile-elements throughout the highland rocks. The major portion of these volatile-bearing phases occur in impact melt-rocks or in breccia matrices. Rhabdites of schreibersite in some of the FeNi grains indicate that there is a meteoritic contribution to the phosphorus in these rocks. Cl/P2O5 ratios in lunar highland rocks are a function of secondary effects, with any apparent Cl-P correlations being coincidential. The present observations preclude the validity of models based on such elemental ratios in these rocks. The presence of rust in the clast laden matrices of pristine rocks indicates fugitive element localization. Pristine clasts may have been contaminated. The basis for a pristine volatile chemistry is questioned.

Hunter, R. H.; Taylor, L. A.

1982-01-01

420

Detection of Volatile Indicators of Illicit Substances by the Olfactory Receptors of Drosophila melanogaster  

PubMed Central

Insects can detect a large range of odors with a numerically simple olfactory system that delivers high sensitivity and accurate discrimination. Therefore, insect olfactory receptors hold great promise as biosensors for detection of volatile organic chemicals in a range of applications. The array of olfactory receptor neurons of Drosophila melanogaster is rapidly becoming the best-characterized natural nose. We have investigated the suitability of Drosophila receptors as detectors for volatiles with applications in law enforcement, emergency response, and security. We first characterized responses of the majority of olfactory neuron types to a set of diagnostic odorants. Being thus able to correctly identify neurons, we then screened for responses from 38 different types of neurons to 35 agents. We identified 13 neuron types with responses to 13 agents. As individual Drosophila receptor genes have been mapped to neuron types, we can infer which genes confer responsiveness to the neurons. The responses were confirmed for one receptor by expressing it in a nonresponsive neuron. The fly olfactory system is mainly adapted to detect volatiles from fermenting fruits. However, our findings establish that volatiles associated with illicit substances, many of which are of nonnatural origin, are also detected by Drosophila receptors. PMID:20530374

Marshall, Brenton; Warr, Coral G.

2010-01-01